Changes in trehalase activity and trehalose level during Ascaris suum (Nematoda) embryogenesis

Summary The levels of trehalose and the activity of trehalase during the development of Ascaris suum eggs were investigated. The level of trehalose in the zygote was high (2.96 ± 0.07 mg/g). During cleavage of eggs, it decreased (0.91 ± 0.35 mg/g). A higher concentration of the sugar was recorded at the blastula and during gastrulation, but it did not reach the uncleaved eggs level. In the early motile larvae, the concentration of trehalose was high (4.58 ± 2.01 mg/g). It decreased with development of L₁ larvae (3.10 ± 1.47 mg/g). A rapid increase in trehalose reserves was observed between the L₁ and L₂ stages. The highest content of trehalose was found in invasive L₂ larvae (5.78 ± 1.39 mg/g). The activity of trehalase at the zygote stage was high (560.22 ± 322.31 U/mg). It decreased at the beginning of cleavage. It was the lowest at the 4–6-cell stage (189.76 ± 114.97 U/mg). An increase in the enzyme activity occurred after reaching the blastula stage (348.44 ± 343.34 U/mg). The highest trehalase activity was recorded during the L₁ larvae stage (635.72 ± 251.16 U/mg). The activity of that enzyme was about three times lower in the invasive stage larvae than in the L₁ larvae.     

Distribution of larval anisakids in blue whiting off Portuguese fish market

Summary Specimens of Micromesistius poutassou (n=238) obtained in a fish market of Oporto, Portugal, were examined for the presence of larval anisakids. Anisakis sp. L₃ larvae (prevalence = 77.7 %; mean intensity = 5.8; mean abundance = 4.5) and Hysterothylacium sp. L₃ larvae (prevalence = 5 %; mean intensity = 4.1; mean abundance = 0.2) were found in body cavity, mesenteries, liver and muscles. The Anisakis sp. intensity and abundance were significantly related to the host body length. The percentage of Anisakis sp. in muscle was inversely related to the host length.     

Changes in hepatic glycogen cycling during a glucose load in healthy humans

Aims/hypothesis Glycogen cycling, i.e. simultaneous glycogen synthesis and glycogenolysis, affects estimates of glucose fluxes using tracer techniques and may contribute to hyperglycaemia in diabetic conditions. This study presents a new method for quantifying hepatic glycogen cycling in the fed state. Glycogen is synthesised from glucose by the direct and indirect (gluconeogenic) pathways. Since glycogen is also synthesised from glycogen, i.e. glycogen→glucose 1-phosphate→glycogen, that synthesised through the direct and indirect pathways does not account for 100% of glycogen synthesis. The percentage contribution of glycogen cycling to glycogen synthesis then equals the difference between the sum of the percentage contributions of the direct and indirect pathways and 100. Materials and methods The indirect and direct pathways were measured independently in nine healthy volunteers who had fasted overnight. They ingested ²H₂O (5 ml/kg body water) and were infused with [5-³H]glucose and acetaminophen (paracetamol; 1 g) during hyperglycaemic clamps (7.8 mmol/l) lasting 8 h. The percentage contribution of the indirect pathway was calculated from the ratio of ²H enrichments at carbon 5 to that at carbon 2, and the contribution of the direct pathway was determined from the ³H-specific activity, relative to plasma glucose, of the urinary glucuronide excreted between 2 and 4, 4 and 6, and 6 and 8 h. Results Glucose infusion rates increased (p<0.01) to ∼50 μmol kg⁻¹ min⁻¹. Plasma insulin and the insulin : glucagon ratio rose ∼3.6- and ∼8.3-fold (p<0.001), respectively. From the difference between 100% and the sum of the direct (2–4 h, 54±6%; 4–6 h, 59±5%; 6–8 h, 63±4%) and indirect (32±3, 38±4, 36±3%) pathways, glycogen cycling was seen to be decreased (p<0.05) from 14±4% (2–4 h) to 4±3% (4–6 h) and 1±3% (6–8 h). Conclusions/interpretation This method allows measurement of hepatic glycogen cycling in the fed state and demonstrates that glycogen cycling occurs most in the early hours after glucose loading subsequent to a fast.     

Post-marathon Paradox in IDDM: Unchanged Insulin Sensitivity in Spite of Glycogen Depletion

Acute physical exercise usually enhances insulin sensitivity. We examined the effect of a competitive 42 km marathon run on glucose uptake and lipid oxidation in 7 runners with insulin-dependent diabetes mellitus (IDDM), aged 36 ± 3 yr, BMI 23.9 ± 0.5 kg m⁻², VO_{2 max} 46 ± 1 ml kg⁻¹ min⁻¹, HbA_1c 7.7 ± 0.3 %, duration of diabetes 16 ± 5 yr, runtime 3 h 47 ± 8 min. On the marathon day, they reduced pre-race insulin doses by 26 ± 8 %, and ingested 130 ± 33 g carbohydrate before, 91 ± 26 g during, and 115 ± 20 g after the race. During the run, blood glucose concentration fell from 14.4 ± 2.0 to 7.4 ± 3.0 mmol l⁻¹ (p < 0.05) and serum insulin from 51 ± 8 to 33 ± 8 pmol l⁻¹ (p < 0.05). Serum NEFA increased by 4-fold (p < 0.05), but fell to the normal level by next morning. Muscle glycogen content was 56 % lower (p < 0.05) and glycogen synthase fractional activity 40 % greater (p < 0.05) in the morning after the marathon as compared to the resting control day. In spite of glycogen depletion, whole body glucose disposal (euglycaemic insulin clamp) was unchanged, while glucose oxidation (indirect calorimetry) was decreased by 49 % (p < 0.05) and lipid oxidation increased by 41 % (p < 0.01). There was an inverse correlation between the rates of lipid oxidation and glucose uptake after the marathon (r = −0.75; p < 0.05). In conclusion: after successfully managed marathon running in patients with IDDM, insulin sensitivity was not increased in spite of low glycogen content and enhanced glycogen synthase activity after marathon, probably because of increased lipid oxidation. © 1997 by John Wiley & Sons, Ltd.     

Hyperinsulinaemia during exercise does not suppress hepatic glycogen concentrations in patients with type 1 diabetes: a magnetic resonance spectroscopy study

Aims/hypothesis We compared in vivo changes in liver glycogen concentration during exercise between patients with type 1 diabetes and healthy volunteers. Methods We studied seven men with type 1 diabetes (mean ± SEM diabetes duration 10 ± 2 years, age 33 ± 3 years, BMI 24 ± 1 kg/m², HbA_1c 8.1 ± 0.2% and VO₂ peak 43 ± 2 ml [kg lean body mass]⁻¹ min⁻¹) and five non-diabetic controls (mean ± SEM age 30 ± 3 years, BMI 22 ± 1 kg/m², HbA_1c 5.4 ± 0.1% and VO₂ peak 52 ± 4 ml [kg lean body mass]⁻¹ min⁻¹, before and after a standardised breakfast and after three bouts (EX1, EX2, EX3) of 40 min of cycling at 60% VO₂ peak. ¹³C Magnetic resonance spectroscopy of liver glycogen was acquired in a 3.0 T magnet using a surface coil. Whole-body substrate oxidation was determined using indirect calorimetry. Results Blood glucose and serum insulin concentrations were significantly higher (p < 0.05) in the fasting state, during the postprandial period and during EX1 and EX2 in subjects with type 1 diabetes compared with controls. Serum insulin concentration was still different between groups during EX3 (p < 0.05), but blood glucose concentration was similar. There was no difference between groups in liver glycogen concentration before or after the three bouts of exercise, despite the relative hyperinsulinaemia in type 1 diabetes. There were also no differences in substrate oxidation rates between groups. Conclusions/interpretation In patients with type 1 diabetes, hyperinsulinaemic and hyperglycaemic conditions during moderate exercise did not suppress hepatic glycogen concentrations. These findings do not support the hypothesis that exercise-induced hypoglycaemia in patients with type 1 diabetes is due to suppression of hepatic glycogen mobilisation. K. Chokkalingam and K. Tsintzas contributed equally to this study.     

Inhibition of glucose production and stimulation of bile flow by R (+)‐α‐lipoic acid enantiomer in rat liver

Abstract: Aims/Background: R (+)‐α‐lipoic acid (RLA) has been suggested for the treatment of liver diseases, but has also been shown to improve glucose utilization in diabetic patients. Because detailed information of RLA action on carbohydrate metabolism in intact liver is lacking, we examined concentration‐dependent effects of RLA on hepatic glucose production. Methods: RLA (10^?6?10^?3 mol L^?1) or buffer (control) was infused in isolated livers of fasted rats during recirculating perfusion for 90 min (n = 4–6/group). Hepatic glucose and lactate fluxes and bile secretion were continuously monitored. Results: RLA reduced lactate (10 mmol L^?1)‐dependent glucose production in concentration‐dependent fashion (R = ? 0.780, P < 0.001) by up to 67% compared with control (0.36 ± 0.02 µmol min^?1 g^?1). In parallel, RLA dose dependently decreased lactate uptake (R = ? 0.592, P < 0.001) also by up to 67% (control: 0.58 ± 0.08 µmol min^?1 g^?1). RLA (10^?4 mol L^?1 and 10^?3 mol L^?1) stimulated bile flow by ～ 20 and ～ 50%, respectively (P < 0.02 vs. control). After 10^?3 mol L^?1 RLA infusion, liver glycogen was ～ 3 fold higher (5.2 ± 1.1 vs. control: 1.8 ± 0.2 µmol g^?1, P < 0.002). Also at low lactate concentrations (1 mmol L^?1), 10^?3 mol L^?1 RLA reduced glucose production by ～ 53% and lactate uptake by ～ 60%, but stimulated bile secretion by ～ 50% (P < 0.05). Conclusion: RLA reduces hepatic glucose release by inhibiting lactate‐dependent glucose production in a concentration‐dependent fashion.     

Estimating the Food Requirements and Prey Size Spectra of Larval American Shad

Abstract

Widespread declines in American shad Alosa sapidissima along the Atlantic coast have been attributed to overfishing, a decrease in water quality, and loss of habitat. Recent surveys along the Roanoke River and Albemarle Sound, North Carolina, suggest that stocks are continuing to decline despite extensive management and stock enhancement efforts. Laboratory experiments were conducted to evaluate the effect of prey density on the growth and survival of American shad and to determine whether larvae can survive and grow in a riverine environment with a limited forage base. Larvae were reared from 11 to 20 d posthatch in one of five treatments: (1) no food; (2) low food (1 prey/L), which simulated the prey densities in the Roanoke River; (3) medium food (50 prey/L), which simulated the prey densities typical of coastal watersheds; (4) high food (500 prey/L); and (5) Artemia spp. (500/L). Larval survival was 35 ± 7% (mean ± SE) and was not significantly different among treatments. Treatments with starved fish had the lowest survival (22 ± 12%), while the highest survival was observed in treatments with high densities of wild zooplankton (46 ± 18%) and Artemia (40 ± 16%). Length-specific growth rates were 0.017 mm/d for the starved treatments and 0.024, 0.029, 0.034, and 0.039 mm/d for the low-prey, medium-prey, high-prey, and Artemia treatments, respectively. Larval growth as a function of length was not significantly different between the Artemia and high-prey treatments; however, growth in these treatments was significantly higher than in those with lower prey densities. Weight-specific growth rates (G_w ) were significantly higher for the Artemia treatment (G_w = 0.129) than for all the other treatments (G_w = 0.081). Analysis of stomach contents indicated that American shad were selectively feeding on the smallest zooplankton (80–250 μm) and that larvae exhibited a strong preference for copepod nauplii and rotifers. These results suggest that spatial and temporal overlap between larvae and zooplankton is important for larval growth and survival.

Received March 31, 2011; accepted September 12, 2011     

The Effect of Intragastric Ammonia Production on Titratable Gastric Acid Output in Helicobacter pylori-Infected Patients with Chronic Gastritis

The purpose of this study was to assess whether intragastric neutralization of HCl by ammonia in Helicobacter pylori-infected patients could meaningfully affect the titratable acid output as a measure of gastric acid secretion in a relation to the severity of infection. In 79 patients with different degrees of Helicobacter pylori infection and chronic gastritis, the basal acid output (BAO) and maximal acid output (MAO) after pentagastrin (6 μg/kg s.c.) was estimated. Cl⁻ and NH₄⁺ contents in these fractions were also assayed. H⁺/Cl⁻ ratio in the MAO fraction was diminished in markedly infected patients (68.1 ± 3.9%, vs 84.1 ± 3.3% in noninfected patients; P < 0.005). Ammonium content was maximal in patients with marked infection (0.912 ± 0.086 vs 0.149 ± 0.034 mmol/hr in MAO [P < 0.001] and 0.475 ± 0.063 vs 0.105 ± 0.016 mmol/hr in BAO of noninfected patients [P < 0.001]), with intermediate values in mild and moderate infection. The NH₄⁺/(H⁺ + NH₄⁺) ratio reached 27.01 ± 7.34% in the BAO of moderately infected patients, vs 10.22 ± 3.81% in noninfected patients (P = 0.05), and 7.25 ± 1.06% in the MAO of markedly infected patients, vs 1.14 ± 0.33% in noninfected patients (P < 0.001). The intragastric ammonia production affects the titratable acid output in Helicobacter pylori-infected patients dependent on the severity of infection. Therefore this factor should be taken into consideration in the evaluation of gastric secretory function in Helicobacter pylori-infected patients. This study was supported by Medical University of Bialystok Grant 514 928.     

Contrasting action of short- and long-term adrenaline infusion on dog skeletal muscle glucose metabolism

Summary There are important differences between the short- and long-term effects of adrenaline on determinants of glucose tolerance. To assess this metabolic adaptation at tissue level, the present study examined the effect of acute and prolonged in vivo elevation of adrenaline on glycogen metabolism and glycolysis in skeletal muscle. Adrenaline (50 ng · kg⁻¹ · min⁻¹) was infused for 2 h or 74 h and the results compared with 1 h 0.9% NaCl infusion in six trained dogs. Muscle glycogen content was reduced by long-term adrenaline (161 ± 17 vs NaCl 250 ± 24 μmol/g dry weight;p < 0.05) but not short-term adrenaline (233 ± 21) indicating a sustained effect of adrenaline on glycogen metabolism. Acutely, glycogen synthase I was reduced (short-term adrenaline 12 ± 6 vs NaC122 ± 7μmol glycosyl units · g⁻¹ · min⁻¹;p < 0.05) but returned to normal with prolonged adrenaline infusion (20 ± 5). In contrast, K_m for glycogen phosphorylasea was not changed acutely (short-term adrenaline 31 ± 6 vs NaCl 27 ± 7 mmol/1 inorganic phosphate) but was reduced during long-term infusion (19 ± 4;p < 0.05 vs short-term adrenaline). Thus, with short- and long-term adrenaline infusion, there were different enzyme changes, although likely to promote glycogenolysis in both cases. In the glycolytic pathway the substrates glucose 6-phosphate and fructose 6-phosphate did not change significantly and hexokinase was not inhibited. Acutely, phosphofructokinase had reduced V_max (short-term adrenaline 34 ± 6 vs NaCl 44 ± 5 U/g; p < 0.05) but was still above the maximal operating rate in vivo. With prolonged adrenaline infusion, the K_m for phosphofructokinase was reduced (long-term adrenaline 0.32 ± 0.03 vs NaCl 0.44 ± 0.07 mmol/l fructose 6-phosphate;p < 0.05). In this situation of relatively low glycolytic flux, the sustained glycogenolytic effect of prolonged adrenaline infusion mediated by increased glycogen phosphorylase a ctivity occurs without a significant accumulation of hexose monophosphates or impairment of glycolysis.     

Endogenous glucose production, gluconeogenesis and liver glycogen concentration in obese non-diabetic patients

Summary Resting, post-absorptive endogenous glucose production (EGP), fractional gluconeogenesis and liver glycogen concentration were assessed in 6 lean and 5 obese non-diabetic subjects undergoing elective abdominal surgery. During the 2 days preceding these measurements, 0.3 g/day U-¹³C glucose had been added to their usual diet to label their endogenous glycogen stores. On the morning of day 3, EGP was measured with 6,6-²H glucose. Their endogenous ¹³C glycogen enrichment was calculated from ¹³CO₂ and respiratory gas exchanges. Fractional gluconeogenesis was assessed as 1-(¹³C glucose/¹³C glycogen) · 100. EGP was similar in lean subjects (113 ± 5 mg/min) and in obese subjects (111 ± 6). Fractional gluconeogenesis was higher in obese (59 ± 10 %) than in lean subjects (29 ± 8 %). However, overall EGP remained constant due to a decrease in glycogenolysis. Since an increased gluconeogenesis and a decreased glycogenolysis may both contribute to increase liver glycogen concentration in obesity, hepatic glycogen concentrations were assessed in hepatic needle biopsies obtained during surgery. Hepatic glycogen concentrations were increased in obese patients (515 ± 38 mg/g protein) compared to lean subjects (308 ± 58, p < 0.05). It is concluded that in obese patients: a) fractional gluconeogenesis is increased; b) overall EGP is unchanged due to a proportional inhibition of glycogenolysis; c) liver glycogen concentration is increased. [Diabetologia (1997) 40: 463–468] Received: 10 April 1996 and in final revised form: 31 December 1996     

Agonist-independent modulation of L-type Ca currents by basal Gs protein activities in single guinea pig ventricular myocytes

The modulation of L-type Ca²⁺ currents (I _Ca,L) by the basal activities of G proteins was studied in adult guinea pig ventricular myocytes by whole-cell patch-clamp techniques. With intrapipette guanosine triphosphate (GTP) (100 μM), a specific inhibition of G_i proteins by pertussis toxin (PTX) produced an increase in the basal density of I _Ca,L (from 11.0 ± 0.8, n = 13, to 25.0 ± 2.0 pA/pF, n = 11, at 0 mV test potential). In addition, PTX shifted the forskolin (Fsk) concentration–I _Ca,L response relation significantly leftward (EC₅₀ = 63.7 ± 12.5 vs 625 ± 75 nM). With intrapipette guanosine diphosphate (GDP)βS (1 mM), the Fsk–I _Ca,L relation was also shifted leftward (EC₅₀ = 197 ± 18.3 vs 781 ± 82.5 nM). However, chronic GDPβS dialysis accelerated the rundown of I _Ca,L significantly, suggesting a potential contribution of G_s proteins in maintaining basal I _Ca,L. In contrast, intra-pipette GTPγS (100 μM) produced a transient rise in I_Ca,L from 11.0 ± 3.0 to 22.8 ± 7.0 pA/pF (in 3.4 min after whole-cell formation at 0 mV, n = 9), presumably through the activation of G_s proteins. It was followed by a gradual decline in I _Ca,L (to 15.5 ± 3.5 pA/pF), which was still enhanced by Fsk (EC₅₀ = 1450 ± 98 nM), indicating that the current decay was not solely due to rundown but to activation of G_i proteins. G_s, in addition to G_i proteins, show sufficient basal activity to modulate I _Ca,L in an agonist-independent manner. Received: October 19, 2000 / Accepted: February 24, 2001     

Neonatal de-afferentation of capsaicin-sensitive sensory nerves increases in vivo insulin sensitivity in conscious adult rats

Summary Sensory neuropeptides, released from the peripheral nervous system, might modulate glucose homeostasis by antagonizing insulin action. The effects of de-afferentation of functional small diameter unmyelinated C-fibres (sensory nerves) on in vivo insulin-mediated intracellular glucose metabolism were investigated by using euglycaemic insulin (6 and 18 mU/kg.min) clamps with [3-³H]-glucose infusion in 24 adult rats, treated neonatally with either capsaicin (CAP) (50 mg/kg) or vehicle (CON). Following the clamp, skeletal muscle groups, liver and adipose tissue were freeze-clamped. At plasma insulin levels of approximately 90 mU/l, CAP-rats showed a 21 % increase in whole body glucose uptake compared with CON (24.4 ± 1.6 vs 20.1 ± 0.8 mg/kg · min, p < 0.02), which was paralleled by a 20 % increase in whole body glycolysis (12.6 ± 0.8 vs 10.5 ± 0.5 mg/kg.min p < 0.05) (concentration of ³H₂O in plasma). Whole body skeletal muscle glycogenesis was increased by 80 % in CAP-rats (5.7 ± 0.7 vs 3.1 ± 0.7 mg/kg · min, p < 0.05) with increased muscle glycogen synthase activity. Whole body (muscle, liver and adipose tissue combined) de novo lipogenesis also was increased in CAP-rats compared with CON (0.69 ± 0.10 vs 0.44 ± 0.06 mg/kg · min, p < 0.05) (incorporation of [3-³H]-glucose counts into glycogen or fat). Hepatic glucose production was lower in CAP-rats compared with CON (0.6 ± 0.6 vs 2.1 ± 0.7 mg/kg · min, p < 0.05). Plasma glucagon, corticosterone, epinephrine and norepinephrine levels were reduced in CAP-rats: 43 ± 2 compared with 70 ± 6 pg/ml, 855 ± 55 compared with 1131 ± 138 nmol/l, 513 ± 136 compared with 1048 ± 164 pmol/l and 928 ± 142 compared with 1472 ± 331 pmol/l, respectively, p < 0.05. At plasma insulin levels of approximately 400 mU/l, CAP-rats showed no differences in peripheral and hepatic insulin action compared with CON. We conclude that the removae of endogenous sensory neuropeptides, by de-afferentation of capsaicin-sensitive sensory nerves, increases in vivo insulin sensitivity, but not responsiveness: 1) primarily through an increased sensitivity of skeletal muscle glycogen synthesis to insulin; 2) through a reduction in the levels of counter-regulatory hormones, thereby creating a milieu which favours overall in vivo insulin sensitivity with respect to glucose uptake, glucose production, glycolysis, glycogenesis and lipogenesis. [Diabetologia (1998) 41: 813–820] Received: 10 November 1997 and in revised form 4 March 1998     

The effect of intense exercise on postprandial glucose homeostasis in Type II diabetic patients

Abstract Aims/hypothesis. The influence of postprandial high intensity exercise on glycaemia was studied in patients with Type II diabetes mellitus. Methods. Patients who were treated by diet only (n = 8) ate a standardised breakfast and 4 h later a standardised lunch. They were studied in the resting state (control day) and on another day (exercise day) when they did intermittent exercised at high intensity after breakfast) (4 bouts including 3 min at 56.5 ± 3.9 % V˙._{O2 max} (means ± SEM), 4 min at 98.3 ± 5.1 % V˙._{O2 max} and 6 min of rest). Responses were calculated as areas under the plasma concentration curve (AUC) during 4 h after either breakfast or lunch. Results. Breakfast-AUCs for glucose, insulin and C peptide were lower (p < 0.05) on the exercise day compared with the control day (glucose: 538 ± 94 vs 733 ± 64 mmol · l^–1· 240 min; insulin: 16 ± 4 vs 22 ± 3 pmol · ml^–1· 240 min; C peptide: 143 ± 22 vs 203 ± 29 pmol · ml^–1· 240 min). After breakfast glucose appearance was unaffected by exercise, whereas disappearance and clearance increased (p < 0.05). Muscle glycogen was diminished by exercise (p < 0.05). After lunch no differences were observed between experiments. Exercise-induced reductions in glucose, insulin and C peptide responses were similar (p > 0.05) in this study of intermittent, high intensity exercise and in a previous study of isocaloric but prolonged moderate (45 min at 53 ± 2 % V˙._{O2 max}) postprandial exercise. Conclusion/interpretation. Postprandial high intensity exercise does not deteriorate glucose homeostasis but reduces both glucose concentrations and insulin secretion. The effect of exercise is related to energy expenditure rather than to peak exercise intensity. Finally, postprandial exercise does not influence glucose homeostasis during a subsequent main meal. [Diabetologia (1999) 42: 1282–1292] Received: 7 May 1999 and in revised form: 5 July 1999     

Resting Physiological Correlates of Reduced Exercise Capacity in Smokers with Mild Airway Obstruction

Smokers with minor spirometric abnormalities can experience persistent activity-related dyspnea and exercise intolerance. Additional resting tests can expose heterogeneous physiological abnormalities, but their relevance and association with clinical outcomes remain uncertain. Subjects included sixty-two smokers (≥20 pack-years), with cough and/or dyspnea and minor airway obstruction [forced expiratory volume in one-second (FEV₁) ≥80% predicted and >5th percentile lower limit of normal (LLN) (i.e., z-score >?1.64) using the 2012-Global Lung Function Initiative equations]. They underwent spirometry, plethysmography, oscillometry, single-breath nitrogen washout, and symptom-limited incremental cycle exercise tests. Thirty-two age-matched nonsmoking controls were also studied. Thirty-three (53%) of smokers had chronic obstructive pulmonary disease by LLN criteria. In smokers [n = 62; age 65 ± 11 years; smoking history 43 ± 19 pack-years; post-bronchodilator FEV₁ z-score ?0.60 ± 0.72 and FEV₁/FVC z-score ?1.56 ± 0.87 (mean ± SD)] versus controls, peak oxygen uptake (?VO₂) was 21 ± 7 vs. 32 ± 9 ml/kg/min, and dyspnea/?VO₂ slopes were elevated (both p < 0.0001). Smokers had evidence of peripheral airway dysfunction and maldistribution of ventilation when compared to controls. In smokers versus controls: lung diffusing capacity for carbon monoxide (D_LCO) was 85 ± 22 vs. 105 ± 17% predicted, and residual volume (RV)/total lung capacity (TLC) was 36 ± 8 vs. 31 ± 6% (both p < 0.01). The strongest correlates of peak ?VO₂ were D_LCO% predicted (r = 0.487, p < 0.0005) and RV/TLC% (r = ?0.389, p = 0.002). D_LCO% predicted was also the strongest correlate of dyspnea/?VO₂ slope (r = ?0.352, p = 0.005). In smokers with mild airway obstruction, associations between resting tests of mechanics and pulmonary gas exchange and exercise performance parameters were weak, albeit consistent. Among these, DLCO showed the strongest association with important outcomes such as dyspnea and exercise intolerance measured during standardized incremental exercise tests.     

Persistent increased lung response to methacholine after normobaric hyperoxia in rabbits

This study was performed to determine the occurrence and time course of airway hyperreactivity following exposure to normobaric hyperoxia. Twenty-six rabbits were studied. Twelve served as control (group 1), and 14 were exposed to normobaric hyperoxia (Fi_O2 ≥ 95%) for 48 h: 9 rabbits (group 2) were studied after 1 day of recovery in room air and 5 (group 3) after 7 days. The rabbits were anesthetized, curarized and artificially ventilated. Respiratory resistance (Rrs) and elastance (Ers) and their respective changes induced by cumulative doses of aerosolized methacholine were assessed by the multiple linear regression analysis of airway pressure, tidal flow and volume. Weight-specific Rrs and Ers were significantly higher in group 2 (respectively, 87.7 ± 6.5 cmH₂O·L⁻¹·sec·kg and 1100.2 ± 87.1 cmH₂O·L⁻¹·kg, mean ± SEM) than in group 1 (respectively, 65.2 ± 3.2 cmH₂O·L⁻¹·sec·kg and 904.4 ± 49.7 cmH₂O·L⁻¹·kg (P < 0.05)), but were not different from group 3 (79.4 ± 7.9 cmH₂O·L⁻¹·sec·kg and 952.3 ± 125.0 cmH₂O·L⁻¹·kg, respectively). The dose of methacholine required to increase Rrs by 50% (PD_Rrs50) was significantly lower in both treated groups: 0.37 ± 0.11 mg in group 2 and 0.51 ± 0.19 mg in group 3 vs 2.07 ± 0.51 mg in group 1 (P < 0.05)). PD_Ers50 was significantly lower in group 2 (0.45 ± 0.15 mg) and 3 (0.75 ± 0.43 mg) compared with controls (1.11 ± 0.26 mg (P < 0.05)). These results show that hyperoxia induces an increase in Rrs and Ers, and airway hyperreactivity in the rabbit. The latter is prolonged beyond the immediate post-exposure period.     

Enzymatic and protein differences between infective larvae of Trichostrongylus colubriformis conditioned or not conditioned to hypobiosis

Summary The differences in protein and enzymatic profiles of infective larvae (L₃) of Trichostrongylus colubriformis, both induced and non-induced to hypobiosis, have been evaluated by means of SDS-PAGE and densitometric analysis as well as by semiquantitative micromethod API-ZYM (Bio-Mérieux, France). Quantitative differences were identified in protein levels between the induced and non-induced larvae, where the amount of two polypeptides (200–220 kDa) decreased in range 32.3–35.4 % and the amount of six polypeptides (20–28 kDa) increased in range 20.0–27.0 % in the samples of induced larvae. In contrast to non-induced larvae, on gelatin-substrate gel in L₃ in vitro released (IVR) proteases from larvae conditioned to hypobiosis, zones of proteolysis were observed between 21 and 34 kDa.     

Measurements of respiratory system resistance by the interrupter technique in healthy and asthmatic children

We studied respiratory system resistance by the interrupter technique (R_int) in healthy and asthmatic children, paying special attention to the effect of cheek compliance and the effects of supporting the cheeks, the influence of lung volume at which interruption was performed, the effect of direction of flow before occlusion (inspiration vs. expiration), and short-term reproducibility of this method. One hundred and thirty-two children (36 controls and 96 asthmatics) were included in the study (mean, 9.0 ± SD 3.6 years). R_int was calculated from the ratio of the alveolar pressure (estimated from mouth pressure during occlusion) to the flow prior to interruption. We observed that (1) underestimation of airway resistance due to upper airway compliance can be minimized by supporting the cheeks; R_int was significantly lower when measured without supporting the cheeks than with support of the cheeks in controls (3.9 ± 0.9 vs. 4.7 ± 1.2 cmH₂O · L⁻¹ · s, respectively) and asthmatics (5.2 ± 1.6 vs 6.9 7 plusmn; 2.0 cmH₂O · L⁻¹ · s); the quantitative differences of R_int with and without cheek support was larger in small children and in the most obstructed children; (2) performing occlusion at mid-tidal volume accurately reflected the respiratory system resistance of the whole respiratory cycle since we observed no difference in R_int when performing occlusion at different volumes during quiet respiration or at the middle of tidal volume; (3) R_int measured during expiration was higher than R_int obtained during inspiration in controls and in asthmatics; moreover, the effect of direction of flow before occlusion was greater in the small children; (4) R_int was closely correlated to height in controls (r = −0.82; P < 0.001); and (5) short-term reproducibility (at 15 min intervals) was satisfactory in controls and asthmatics (coefficients of variation were 9% and 7%, respectively). Pediatr. Pulmonol. 1997;24:78–85. © 1997 Wiley-Liss, Inc.     

Tpeak-Tend Interval as an Index of Global Dispersion of Ventricular Repolarization: Evaluations Using Monophasic Action Potential Mapping of the Epi- and Endocardium in Swine

The ECG interval from the peak to the end of the T wave (T_peak-T_end) has been used as an index of transmural dispersion of ventricular repolarization (DVR). The correlation between the T_peak-T_end interval and the global DVR, however, has not been well-evaluated. Methods: Monophasic action potentials (MAPs) were recorded from 51 ± 10 epicardial and 64 ± 9 endocardial sites in the left ventricles of 10 pigs, and from 41 ± 4 epicardial and 53 ± 2 endocardial sites in the right ventricles of 2 of the 10 pigs using the CARTO mapping system. The end of repolarization times over the epi- and endocardium were measured, and the end of repolarization dispersions over the epicardium (DVR-epi), over the endocardium (DVR-endo) and over both (DVR-total) were calculated. The QT_peak, QT_end and T_peak-T_end intervals as well as the QT_peak and QT_end dispersions were obtained from the simultaneously recorded 12-lead ECG. Results: The maximal T_peak-T_end intervals (57 ± 7 ms) were consistent with the DVR-total (58 ± 11 ms, p > 0.05), and significantly correlated with the DVR-total (r = 0.64, p < 0.05). However, the mean T_peak-T_end intervals (44 ± 5 ms), and T_peak-T_end intervals from lead II (41 ± 6 ms) and V₅ (43 ± 5 ms) were all significantly smaller than and poorly correlated with the DVR-total, as were the QT_peak and QT_end dispersions (15 ± 2 ms vs. 21 ± 4 ms). Conclusion: The maximal T_peak-T_end interval may be used as a noninvasive estimate for the global DVR, but not the QT_peak and QT_end dispersions, nor the mean T_peak-T_end interval and that from a single lead.     

Changes in serum amylase, lipase and leukocyte elastase during diabetic ketoacidosis and poorly controlled diabetes

Diabetic ketoacidosis (DKA) is frequently associated with pancreatic enzyme abnormalities. In order to determine the main factors that lead to this increase, serum total amylase (TA), pancreatic amylase (PA), lipase (L) and leukocyte elastase (LE), an early predictor of acute pancreatitis, were measured in four groups of patients on admission. Group 1 consisted of 52 patients with DKA (age: 41.9 ± 19.2 years; blood glucose (Glc): 27.4 ± 11.5 mmol/L; pH: 7.20 ± 0.16; plasma bicarbonate: 10.5 ± 6.2 mmol/L; blood urea nitrogen (BUN): 0.60 ± 0.44 g/L; HbA_1C: 12.5% ± 2.8%). Group 2 consisted of 90 patients with poorly controlled non-ketotic diabetes (age: 53.4 ± 16.0; Glc: 14.3 ± 0.6; HCO₃ ⁻: 26.6 ± 3.2; BUN: 0.38 ± 0.20; HbA_1C: 11.3 ± 2.1). Group 3 consisted of 22 patients with well-controlled diabetes (age: 53.7 ± 12.8; Glc: 10.1 ± 5.2; HCO₃ ⁻: 27.4 ± 3.8; BUN: 0.36 ± 0.19; HbA_1C: 6.8 ± 0.8). Group 4 (controls) comprised 27 non-diabetic patients (age: 46.0 ± 15.0; Glc: 4.9 ± 0.5; HCO₃ ⁻: 28.4 ± 2.5; BUN: 0.30 ± 0.16; HbA_1C: 5.2 ± 0.7) (means ± SD). Increased enzyme activities were more frequent in group 1 (TA: 30.7; PA: 27.0; L: 36.5; LE: 73%) than in groups 2 (TA: 8.9; PA: 7.1; L: 8.9; LE: 45.5%), 3 (TA: 13.6; PA: 9.0; L: 18.1; LE: 31.8%) and 4 (TA: 7.0; PA: 3.0; L: 0.0; LE: 29.6%). Mean serum enzyme activities were significantly different in the 4 groups (ANOVA, P < 0.01) and were higher in group 1 than in groups 2, 3 and 4 (Student's t-test; group 1 vs 2 or 3 or 4: P < 0.001). In groups 1 + 2 + 3 + 4 (all patients), the four enzymes correlated with one another and also with Glc, BUN and HCO₃ ⁻ (P < 0.001). In group 1, TA correlated negatively with HCO₃ ⁻ (P < 0.001) and pH (P < 0.05); PA and L correlated positively with Glc and BUN (P < 0.01) and negatively with HCO₃ ⁻ (respectively, p < 0.01 and 0.05). PA correlated positively with pH (P < 0.01); LE correlated with Glc (P < 0.05) and BUN (P < 0.01). In conclusion, this study suggests that the serum levels of pancreatic enzymes increase with the degree of diabetic disequilibrium, and mainly correlate with metabolic factors such as hyperglycaemia, dehydration and acidosis. Increased pancreatic enzyme activities in patients with DKA, even in combination with abdominal pain, should not be diagnosed as acute pancreatitis; this could be important, particularly for younger clinicians. Received: 18 September 1998 / Accepted in revised form: 24 February 1999     

Glycaemic and nonglycaemic effects of pioglitazone in triple oral therapy of patients with type 2 diabetes

Objectives. To examine pioglitazone as add‐on to metformin and insulin secretagogues in patients with type 2 diabetes and inadequate glycaemic control and its effect on glycaemic control, surrogate measures of insulin sensitivity (adiponectin) and β‐cell function (proinsulin/insulin) and fluid retention. Design and setting. Prospective open‐label study of 54 patients with type 2 diabetes and HbA_1c≥6.5% admitted to outpatient unit at Malmö University Hospital. The patients received 30–45 mg pioglitazone daily during 26 weeks in addition to their existing antidiabetic medication. After 26 weeks, one‐third of patients were followed for 3 months without pioglitazone. Results. HbA_1c decreased (7.8 ± 0.9–6.3 ± 0.9%, P < 0.001) with 61% of patients achieving levels <6.5%. However, in the group followed for another 3 months HbA_1c increased (6.1 ± 0.73–7.1 ± 0.9, n = 18, P < 0.001) after pioglitazone withdrawal. Adiponectin increased (6.1 ± 2.8–13.2 ±5.8 μg mL^?1, P < 0.001) and the proinsulin to insulin ratio decreased (0.89 ± 0.66–0.66 ± 0.53, P < 0.001). Nt‐proBNP increased from 487.3 ± 252.2 to 657.8 ± 392.1 pmol L^?1 (P < 0.001). Conclusions. Pioglitazone is effective in achieving glycaemic targets and reducing risk factors involved in atherosclerosis and improving β‐cell function when used as part of triple oral therapy in patients with type 2 diabetes and secondary drug failure. Nt‐proBNP increase with concomitant decrease in haemoglobin suggests a subclinical sign of fluid retention.