Secretory component and lactoferrin in pure pancreatic juice in chronic pancreatitis

To evaluate pathophysiological roles of proteins in pancreatic secretion, immunoreactive lactoferrin (LF) and secretory component (SC) were measured in the first fraction of the pure pancreatic juice obtained endoscopically from 17 control, 21 suspected (SCP), 14 noncalcified (NCP), and 14 calcified chronic pancreatitis (CCP) subjects. The protein and amylase tended to decrease both in concentration and output from control to CCP. LF concentration was elevated in CCP (18.0±4.9/ml) when compared with controls (2.3±0.2g/ml), and LF output in NCP (12.3±3.8 g/min) was increased from controls (3.8±0.6 g/min). The combination of high LF concentration with low protein output was observed in 10/14 in CCP but 0/14 in NCP and can be a biochemical discriminator of CCP from NCP. SC concentrations were also elevated in NCP (8.5±2.0 g/ml) and CCP (5.6±1.6 g/ml) from controls (1.2±0.2 g/ml). SC outputs in SCP (9.8±3.1 g/min) and NCP (21.1±4.8 g/min) were increased from controls (1.7±0.3 g/min), but there was no further increase in CCP. Hypersecretion of LF and SC in chronic pancreatitis is different, especially in CCP, although the mechanisms for hypersecretion are unknown.This study was supported in part by a research grant for intractable pancreatic disease from the Ministry of Health and Welfare, Japan.     

Klinisch-chemische Ultramikromethoden

Zusammenfassung Es werden Probleme und Möglichkeiten bei Arbeiten im Größenordnungsbereich von Mikrolitern (1 l=0.001 ml) dargestellt und eine Grundausrüstung beschrieben, welche es gestattet, klinisch-chemische Analysen ausgehend von kleinsten Probenmengen (5–20 l) einfach, rasch und zuverlässig auszuführen. Die Arbeitsweise von halbautomatischen Pipettenflaschen, einer Ultramikrobürette, eines speziellen Spektro-Kolorimeters und anderer apparativer Hilfsmittel wird dargestellt.

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Summary The problems and practicability of working with microliters (1 l=0.001 ml.) are presented. A basic apparatus is described, which permits the simple, rapid and reliable clinical-chemical analysis of very small samples (5–20 l.). Directions are given for the operation of semiautomatic pipettes, an ultramicroburette, a special spectrocolorimeter and other auxilliary apparatus.

     

Modulation of pacemaker activity in sheep cardiac Purkinje fibers by stimulation of β-adrenoceptor subtypes

The electrophysiological effects mediated by ₁- and ₂- in spontaneously active sheep cardiac Purkinje fibers were investigated using the non-selective agonist (–)-isoproterenol (IPN) and the selective agonists (–)-noradrenaline (₁) and procaterol (₂) in the absence and presence of the selective antagonists bisoprolol (₁) and ICI 118,551 (₂).IPN (0.01 mol/l) increased the spontaneous rate by 54% and the slope of diastolic depolarization by 68% of the respective control values. Further, IPN increased the action potential duration at –20 mV (APD –20 mV) from 96 to 154 ms, reduced the APD –70 mV by 17% and the duration of the diastole by 39% and slightly hyperpolarized the maximum diastolic potential. These effects were partially inhibited by ICI 118,551 (0.03 mol/l), diminished by bisoprolol (0.1 mol/l) and almost completely blocked by the combination of both antagonists. Concentration response curves of IPN were influenced by the selective antagonists as follows: ICI 118,551 (0.03 mol/l) shifted the curves to the right by 0.2–0.4 log units and increased the slope factor. Bisoprolol (0.1 mol/l) induced a greater shift to the right by 1.1–1.5 log units. Combination of bisoprolol with ICI 118,551 shifted the curves to the right by 1.5–1.7 log units.Noradrenaline (0.3 mol/l) elicited similar actions as IPN. Bisoprolol (0.1 mol/l) shifted the concentration response curves of noradrenaline to the right by 1.1–1.9 log units. Actions of procaterol (0.1 mol/l) were weak, attained only 15–35% of the maximal effects of IPN and could be blocked by ICI 118,551 (0.03 mol/l).These results show that the increase of pacemaker activity induced by catecholamines in sheep cardiac Purkinje fibers is predominantly mediated by stimulation of ₁. However, contribution of ₂ mediated effects could be demonstrated.Supported by Ministerium für Wissenschaft und Forschung, Nordrhein-Westfalen, Projekt-Nr, 40008786.     

Age-related Variations in the Neuroendocrine Control,More Than Impaired Receptor Sensitivity,Cause The Reduction in the GH-releasing Activity of GHRPs in Human Aging

The mechanisms underlying the reduction in the GH-releasing activity of GHRPs in aging are still unclear. Aim of our study was to verify in man whether age-related impairment of the neurohormonal control of GH secretion and/or receptor alterations are involved in the reduced GH response to GHRPs in aging. To this goal, in 16 normal elderly subjects (E, 66–81 yr) and 12 young controls (Y, 24–28 yr) we studied the effects of 1.0, 2.0 and 3.0 g/kg iv Hexarelin (HEX), a synthetic hexapeptide, or GHRH, as well as the interaction among HEX (2.0 g/kg), GHRH (2.0 g/kg) and arginine (ARG, 0.5 gr/kg) on GH secretion. In Y the GH response to increasing doses of HEX (1.0 vs. 2.0 vs. 3.0 g/kg; AUC0;v–120 ± SEM: 1728.4 ± 406.4 vs. 2265.9 ± 298.4 vs. 2934.3 ± 482.2 g//L/h, p < 0.05 for 1.0 vs. 2.0 g/kg) and GHRH (649.6 ± 111.4 vs. 792.2 ± 117.6 vs. 1402.6 ± 363.0 g/L/h) showed a progressive increase. Two g/kg HEX and 1 g/kg GHRH were the maximal effective doses. Similarly, in E the GH response to increasing doses of HEX (336.7 ± 50.0 vs. 742.8 ± 157.9 vs. 1205.1 ± 178.1 g/L/h, p < 0.05 for 1.0 vs. 2 g/kg, p < 0.001 for 1.0 vs. 3.0 g/kg and p < 0.03 for 2.0 vs. 3.0 g/kg) and GHRH (183.8 ± 27.3 vs. 260.9 ± 17.3 vs. 356.1 ± 46.3 g/L/h, p < 0.005 for 1.0 vs. 3.0 g/kg and p < 0.05 for 2.0 vs. 3.0 g/kg) showed a progressive increase. In E the GH response to 3 g/kg HEX or GHRH were clearly higher than those to 2 g/kg. However, at each dose the GH responses to HEX or GHRH in E were lower (p < 0.05) than those in Y. In Y the GH response to HEX + GHRH was synergistical (4259.2 ± 308.0 g/L/h, p < 0.05). ARG strikingly potentiated the GHRH-induced GH rise (2640.8 ± 273.6 g/L/h, p < 0.01) but not the HEX-induced one (2371.7 ± 387.2 g/L/h) as well as the synergistical effect of HEX and GHRH (4009.1 ± 360.8 g/L/h). In E the GH response to HEX and GHRH was still synergistical (1947.7 ± 306.0 g/L/h, p < 0.05) but these responses were lower than those in young (p < 0.01). On the other hand, in E ARG restored the GH response to GHRH (1858.9 ± 172.8 g/L/h, p < 0.01) and even those to HEX (2069.5 ± 528.7 g/L/h, p < 0.01) and HEX + GHRH (4406.0 ± 1079.2 g/L/h, p < 0.05). Our present results indicate that the impairment of GHRP and GHRH receptor activity may have a role in the reduction of the somatotrope responsiveness in aging. However, the age-related reduction in the GH-releasing activity of GHRPs seems mainly dependent on age-related variations in the neural control, i.e. concomitant GHRH hypoactivity and somatostatinergic hyperactivity.     

17β-Estradiol Attenuates Quinolinic Acid Insult in the Rat Hippocampus

A number of studies have shown that 17-estradiol has neuroprotective properties. In this study the neuroprotective effect of 17-estradiol against quinolinic-acid-induced neuronal damage was investigated. Ovariectomized rats were separated into three groups of five animals each. Rats received daily subcutaneous injections of either olive oil or 17-estradiol in olive oil for 7 days prior to and following a single intrahippocampal injection of 1 mol quinolinic acid in 2 L phosphate-buffered saline. The brains were removed and the hippocampi either sectioned and stained for microscopic examination or used in glutamate receptor saturation binding studies. Glutamate receptor displacement binding studies were also performed using concentrations of 0.05 nM–5 M 17-estradiol or quinolinic acid. The results show that 17-estradiol protects hippocampal neurons from quinolinic-acid-induced neurodegeneration by competing with quinolinic acid to bind to the N-methyl-D-aspartate (NMDA) receptor. This would result in a decrease in intracellular free-calcium influx and resultant neuronal swelling.     

Loss of glycogen during preconditioning is not a prerequisite for protection of the rabbit heart

Depletion of gycogen has been proposed as the mechanism of protection from ischemic preconditioning. The hypothesis was tested by seeing whether pharmacological manipublation of preconditioning causes parallel changes in cardiac glycogen content. Five groups of isolated rabbit hearts were studied. Group 1 experienced 30 min of ischemia only. Group 2 (PC) was preconditioned with 5 min of global ischemia followed by 10 min of reperfusion. Group 3 was preconditioned with 5 min exposure to 400 nM bradykinin followed by a 10 min washout period. Group 4 experienced exposure to 10 M adenosine followed by a 10 min washout period, and the fifth group was also preconditioned with 5 min ischemia and 10 min reperfusion but 100 M8-(p-sulfophenyl) theophylline (SPT), which blocks adenosine receptors, was included in the buffer to block preconditioning's protection. Transmural biopsies were taken before treatment, just prior to the 30 min period of global ischemia, and after 30 min of global ischemia. Glycogen in the samples was digested with amyloglucosidase and the resulting glucose was assayed. Baseline glycogen averaged 17.3±0.6 mol glucose/g wet weight. After preconditioning glycogen decreased to 13.3±1.3 mol glucose/g wet weight (p<0.005 vs. baseline). Glycogen was similarly depleted after pharmacological preconditioning with adenosine (14.0±1.0 mol glucose/g wet weight, p<0.05 vs. baseline) suggesting a correlation. However, when proconditioning was performed in the pressence of SPT, which blocks protection, glycogen was also depleted by the same amount (13.3±0.7 mol glucose/g wet weight, p=ns vs. PC). Bradykinin, which also mimics preconditioning, caused no depletion of glycogen (16.3±0.8 mol glucoseig wet weight, p=ns vs. baseline). Because preconditioning with bradykinin did not deplete glycogen and because glycogen continued to be low when protection from preconditioning was blocked with SPT, we conclude that loss of glycogen per se does not cause the protection of preconditioning.     

Increased plasma fibronectin in patients with systemic lupus erythematosus

Summary To add to our knowledge of collagen diseases, plasma fibronectin (FN) in patients with systemic lupus erythematosus (SLE) has been measured, and it was determined that the plasma FN value in those with SLE was 454±36 g/ml, is significantly higher than the FN value in normal subjects (234±21 g/ml. Further, the plasma FN value of patients with active SLE was significantly higher (591±46 g/ml than that of patients with non-active SLE (287±31 g/ml. The plasma FN value of SLE patients was also seen to be associated with the peripheral blood platelet count and with the dose level of the corticosteroid hormone administered to patients. In active SLE patients, it was similarly found that the plasma FN value had a significant correlation with the peripheral blood lymphocyte count and with the dose level of the corticosteroid hormone given to patients. Since the plasma FN value is known to be high in untreated SLE patients, it was felt that the increase of the FN value in SLE patients is not due to the effect of the corticosteroid but to the disease itself.     

A Three-dimensional Analysis of Blood Vessels in Bronchioloalveolar Carcinoma

The three-dimensional architecture of blood vessels within lung adenocarcinomas has not been well studied. In 19 cases with bronchioloalveolar carcinoma with central fibrosis, we three-dimensionally examined blood vessel architecture in 150 m thick sections stained with elastin staining and anti-CD34 antibody. We examined four regions: normal alveoli and three regions within the tumor including an area adjacent to the normal alveoli (external area), an area in which tumor cells were replacing epithelial cells (replacement area), and a central fibrotic area (fibrotic area). Elastin staining showed that elastic fibers formed the framework of the alveoli, and the alveolar structure shrank more strongly to the center of the tumor due to folding of alveolar walls invaded by adenocarcinoma cells. We also measured three vessel parameters in these four regions. The vessel diameters were 4.08±1.10 m, 3.95±1.02 m, 5.04±1.56 m, and 6.11±2.23 m, the circumferences of those vessels seen as complete circles were 43.11±12.78 m, 43.71±12.87 m, 95.21±39.32 m, and 126.77±54.65 m; the lengths between vessel bifurcations were 13.28±3.08 m, 13.47±4.58 m, 24.91±9.66 m, and 41.82±28.08 m in the normal alveoli, and the external, replacement, and fibrotic areas, respectively. Blood vessel architecture changed such that the vessels became larger and coarser towards the center of the tumor. Our three-dimensional analysis suggests continuous remodeling of alveolar capillaries rather than angiogenesis within bronchioloalveolar carcinoma.     

Acid-Independent Gastroprotective Effects of Lansoprazole in Experimental Mucosal Injury

The protective effects of the proton pumpinhibitor lansoprazole on gastric mucosal damage inducedby ethanol-HCl or hemorrhagic shock were investigated inthe present study. The morphometric analysis of gastric histological sections revealed thatlansoprazole dosedependently reduced mucosal injuryevoked by ethanol-HCl (ED₅₀ = 24.3mol/kg) or hemorrhagic shock (ED₅₀ = 38.9mol/kg), these effects being associated with markedincrements of Alcian blue recovery from gastric boundmucus (ED₅₀ = 31.4 mol/kg and 27.6mol/kg, respectively). In addition, lansoprazoleinhibited gastric acid secretion from pylorusligated rats(ED₅₀ = 9.8 mol/kg). Further experiments,performed on rats with ethanol-HCl-induced gastricinjury, indicated that the protective effects of lansoprazole were not modified by L-365,260,suramin, N^G-nitro-L-arginine, or systemicablation of capsaicin-sensitive sensory nerves, whereasthey were partly blocked by indomethacin and fullyprevented by N-ethyl-maleimide. In addition, lansoprazoledid not modify somatostatin concentrations in gastricmucosa. The present results provide evidence thatlansoprazole prevents the necrotic damage of gastric mucosa induced by ethanol-HCl or hemorrhagicshock. According to the rank order of ED₅₀values, these effects appear to depend mainly on theenhancement of the gastric mucus barrier rather than on the reduction of acid secretion. It is alsoproposed that an increased production of prostaglandins,as well as an increased availability of sulfhydrylcompounds at level of gastric mucosa may account for the gastroprotective effects oflansoprazole.     

Evaluation of rat insulin messenger RNA in pancreatic and extrapancreatic tissues

Summary The purpose of these studies was to determine whether insulin detected immunochemically in extrapancreatic tissues of the adult rat is synthesized in situ by quantitating mRNA in these tissues. A blot hybridization assay was utilized with cloned ³²P-proinsulin cDNA. The lower limit of detection was estimated to be 3pg. Proinsulin mRNA concentration was found to be 1000–1500 g in isolated pancreatic islets and was easily detected in total pancreatic RNA at 10–15 pg/ g. Proinsulin mRNA was quantitated in rat insulinoma cells adapted to culture at levels 150 those in normal islets. Samples of RNA (20–50 g) enriched about 50-fold for mRNA sequences by repeated oligo-deoxythymidylate chromatography were assayed. No insulin mRNA was detected in 50 g samples of RNA from brain or in 20 g samples from subsections of brain or other extrapancreatic tissues. RNA samples were undegraded as assessed by ability to stimulate protein synthesis in a cell-free system. Proinsulin mRNA from pancreas was added to brain homogenates and recovered intact. Brain RNA samples with insulin mRNA levels 1:1000 that of pancreas would be predicted to have 50–75 pg proinsulin mRNA/50 g sample assayed if present. Because none was found, brain must have a concentration <1:6,000 that of pancreas. These findings suggest that immunoassayable insulin detected in extrapancreatic tissues of the adult rat is synthesized by the pancreas.     

C-reactive protein (CRP) levels in systemic lupus erythematosus (SLE)

Summary CRP levels in 194 serum samples from 43 SLE patients were measured. Patients with inactive disease have levels below 10 g/ml; patients with active SLE have higher levels, but never over 50 g/ml. In the presence of infection or inflammatory processes, regardless of the activity of SLE, the levels are significantly higher (p<0.05), and well over 50 g/ml. Both active SLE patients and inactive SLE patients with local infections have levels between 10 g/ml and 50 g/ml. In this situation, the presence of anti-DNA antibodies strongly suggests disease activity (82% versus 9%, p<0.05). The clinical and physiopathological meaning of these findings is discussed.     

Role of Central Interleukin-1β in Gastrointestinal Motor Disturbances Induced by Lipopolysaccharide in Sheep

Cytokines are involved in the symptoms of theacute phase response induced by infectious diseases inhumans as well as in animals, and interleukin-1(IL-1 ) has a pivotal role in these changes. The role of central IL-1 in the gastrointestinalhypomotility and fever evoked by intravenousadministration of lipopolysaccharide (LPS) and themechanisms involved, were investigated in sheep as anexperimental model. LPS (0.1 g/kg, intravenously)induced gastrointestinal hypomotility and fever thatwere significantly reduced by priorintracerebroventricular administration of IL-1receptor antagonist protein (IL-1ra, 2 g/kg). The effects of LPS were mimickedby intracerebroventricular IL-1 (50 ng/kg),whereas IL-1 injected intravenously at the samedose only caused a slight and transient fever withoutmodifying the gastrointestinal motility. Priorintracerebroventricular administration of thecyclooxygenase inhibitor indomethacin (100 g/kg) butnot the corticotropin-releasing factor (CRF) receptorantagonist -helical CRF_9-41 (5 g/kg) blocked alleffects evoked by both LPS and IL-1. These resultssuggest that in sheep, LPS induces digestive motordisturbances through a central release of IL-1 andprostaglandins.     

α2-Adrenergic stimulation counteracts glucose-induced rise of sodium in pancreatic islets exposed to ouabain

The effects of ₂-adrenergenic activation by clonidine on sodium handling were analysed in beta-cell-rich pancreatic mouse islets. In the steady-state situation, clonidine (1 M) amplified lowering of sodium induced by 20 mM glucose, while the content remained unchanged in 3 mM glucose. The loss of sodium in Na⁺-deficient medium was stimulated by glucose but was not affected by clonidine. This agonist also did not influence the ouabain-induced uptake of sodium at 3 mM glucose but partially counteracted additional uptake in response to 20 mM glucose. Although lacking effects of its own, 5 M yohimbine completely counteracted the action of clonidine. The glucose amplification of the ouabain-induced uptake of sodium was suppressed also by 10 M of the Ca²⁺-channel blockers methoxyverapamil and diltiazem. Both tolbutamide (100 M) and dibutyryl cyclic AMP (1 mM) mimicked the action of glucose by promoting clonidine-sensitive uptake of sodium in the presence of ouabain. It is concluded that activation of ₂-adrenoceptors has profound effects on the sodium handling of pancreatic beta-cells exposed to glucose and other stimulators of insulin release.     

Modulation of hepatic glucose production by non-esterified fatty acids in Type 2 (non-insulin-dependent) diabetes mellitus

Summary To study the effect of changes in plasma non-esterified fatty acid concentration on suppression of hepatic glucose production by insulin eight Type 2 (non-insulin-dependent) diabetic patients participated in three euglycaemic, hyperinsulinaemic (108pmol · m^2–1 · min^–1) clamp studies combined with indirect calorimetry and infusion of [3-³H]-glucose and [1-¹⁴C]palmitate; (1) a control experiment with infusion of NaCl 154 mmol/l, (2) heparin was infused together with insulin, and (3) an antilipolytic agent, Acipimox, was administered at the beginning of the experiment. Six healthy volunteers participated in the control experiment. Plasma non-esterified fatty acid concentrations during the insulin clamp were in diabetic patients: (1) 151±36 mol/1, (2) 949±178 mol/l, and (3) 65±9 mol/l; in healthy control subjects 93±13 mol/l. Non-esterified fatty acid transport rate, oxidation and non-oxidative metabolism were significantly higher during the heparin than during the Acipimox experiment (p<0.001). Suppression of hepatic glucose production by insulin was impaired in the diabetic compared to control subjects (255±42 vs 51±29 mol/min, p<0.01). Infusion of heparin did not affect the suppression of hepatic glucose production by insulin (231±49 mol/min), whereas Acipimox significantly enhanced the suppression (21±53 mol/min, p<0.001 vs 154 mmol/l NaCl experiment). We conclude that insulin-mediated suppression of hepatic glucose production is not affected by increased non-esterified fatty acid availability. In contrast, decreased non-esterified fatty acid availability enhances the suppression of hepatic glucose production by insulin.     

Comparison Between Ischaemic and Anisomycin-Induced Preconditioning: Role of p38 MAPK

To further evaluate the significance of p38 MAPK as trigger or mediator in ischaemic preconditioning, anisomycin and SB 203580 were used to manipulate its activation status. Special attention was given to the concentration of the drugs and protocols used.The isolated perfused rat heart, subjected to either 25 min global ischaemia or 35 min regional ischaemia, was used as experimental model. This was preceded by anisomycin (2 or 5 M: 3 × 5 min; 5 M: 5 min or 10 min; 5 M: 10 min + 10 min washout or 20 M: 20 min) or SB 203580 (2 M: 3 × 5 min; before and during 3 × 5 min or 1 × 5 min ischaemic preconditioning; 10 min). Endpoints were functional recovery during reperfusion and infarct size.Anisomycin, regardless of the protocol, reduced infarct size, but did not improve functional recovery. In a number of experiments activation of JNK by anisomycin was blocked by SP 600125 (10 M). SP 600125 had no effect on the anisomycin-induced reduction in infarct size. SB 203580 when administered for 10 min before sustained ischaemia, improved functional recovery and reduced infarct size. SB 203580 could not abolish the beneficial effects of a multi-cycle preconditioning protocol, but it significantly reduced the outcome of 1 × 5 min preconditioning. In all hearts improved functional recovery and reduction in infarct size were associated with attenuation of p38 MAPK activation during sustained ischaemia-reperfusion.The results indicate that activation of p38 MAPK acts as a trigger of preconditioning, while attenuation of its activation is a prerequisite for improved recovery and a reduction in infarct size.     

Inhibition of canine gastric acid secretion by an H-1 receptor antagonist to histamine

Histamine H-2 receptors are thought to mediate gastric acid secretory responses, where-as H-1 receptors supposedly regulate mucosal vascular responses to histamine. In an in vivo chambered canine stomach flap preparation, the H-1 receptor antagonist, tripelennamine, injected intraarterially (22.1 mol/kg) into the stomach flap reduced histamine-stimulated (1.25 /kg/min intravenously) acid secretion by approximately two thirds with a secondary reduction in gastric mucosal blood flow. This antisecretory action does not appear to be due to nonspecific mucosal damage. The H-2 receptor antagonist, metiamide, injected intraarterially (2.5 mol/kg) also inhibited gastric acid secretion by about two thirds as did intravenously injected metiamide (4.5 mol/kg), whereas intravenously administered tripelennamine (40.8 mol/kg) was ineffective as an acid secretory inhibitor. Intraarterial tripelennamine reduced the secretory actions of the H-2 agonist, 4-methyl-histamine (2.2 g/kg/min intravenously), while intravenous metiamide depressed the gastric mucosal dilator responses to the H-1 agonist, 2-methylhistamine (5 g/kg/min intravenously). Both histamine-receptor antagonists also reversed the systemic circulatory depressor effects of histamine and its analogs. These results suggest the need for reevaluation of inferences based upon the assumed specificity of H-2 and H-1 agonists and antagonists.     

Inhibition of basal and stimulated gastric H+ and pepsin secretion in duodenal ulcer patients by metiamide,an H-2 histamine antagonist

Metiamide was given orally in one dose of 200 mg in 23 studies in patients with duodenal ulcer, 4 in the basal state, 11 during histamine infusion, and 8 before insulin hypoglycemia stimulation. In the latter 8 patients insulin was given at another time without metiamide. In 17 studies acid secretion was suppressed by metiamide—up to 75% in the basal state, 53% after histamine, and 80% after insulin. Pepsin secretion was reduced to the same extent as H⁺ in the histamine studies but not in the basal (57%) or insulin (44%) studies, so that in the latter pepsin/acid ratios were 3-fold greater than in controls. Blood levels of metiamide were measured in 17 studies. In 10 out of 11 who showed inhibition of 40% or more, peak blood levels of metiamide were 0.45 g/ml to 1.25 g/ml. In 5 of 6 who did not show inhibition, blood levels were 0.05–0.4 g/ml; in the sixth it was 0.8 g/ml. Therefore a critical blood level for suppression of basal or stimulated secretion appears to be 0.45 g/ml.Supported by Public Health Service Grants AM09260 and AM05286; and by a Grant-in-Aid from Smith Kline & French Laboratories; Veterans Administration Hospital, Birmingham, Alabama, Research Project 3649-01.     

The ability of heat stress and metabolic preconditioning to protect primary rat cardiac myocytes

Primary rat cardiocytes were subjected to either thermal preconditioning for 30 min at 43°C or 20 min metabolic preconditioning (10 mM deoxyglucose, 20 mM lactate, pH 6.5). Eighteen hours later cells were analysed either for hsp 70i expression or subjected to a subsequent lethal heat stress or simulated ischaemia (10 mM deoxyglucose, 20 mM lactate, 0.75 mM sodium dithionite, 12 mM potassium chloride, pH 6.5) for 2 hours and assessed for survival by trypan blue exclusion.Hsp 70i was induced over 100 fold by thermal preconditioning and 30 fold by metabolic preconditioning (p<0.001, p<0.05), hsp 90 was induced 2.71 fold and 2.24 fold (p<0.001, p<0.001) by thermal and metabolic preconditioning respectively, while hsp 60 was not induced by either treatment. Preconditioned cultures had improved survival against subsequent lethal heat stress or simulated ischaemia: Thermal preconditioning reduced death from 69.22% to 52.46% upon subsequent lethal heat stress and from 49.13% to 36.66% upon subsequent lethal simulated ischaemia. Metabolic preconditioning reduced cell death from 51.29% to 33.8% against subsequent lethal heat stress, and from 69.09% to 55.61% upon subsequent lethal simulated ischaemia. A second marker of cell death, the release of lactate dehydrogenase activity into the culture media, was reduced to 65% and 60% of control values for thermally preconditioned cells subjected to lethal heat or lethal simulated ischaemia respectively. Metabolically preconditioned cells demonstrated lactate dehydrogenase activity of 59% and 51% that of control values, when subjected to lethal heat or lethal simulated ischaemia respectively.Abbreviations hsp heat stress protein - hsp 70i inducible 70 kDa heat stress protein - LDH lactate dehydrogenase - PBS phosphate buffered saline     

A sensitive double antibody radioimmunoassay for Human Growth hormone (HGH): levels of serum HGH following rapid tolbutamide infusion

Summary A double antibody radio-immunoassay for human growth hormone is described. — The assay can detect 0.0625 mg HGH/ml serum and has good reproducibility. It was found that: 1. a highly pure labelled hormone; 2. a specific and very potent guinea pig antihuman growth hormone antibody; and 3. at least five days of incubation for the first reaction were necessary to achieve this accuracy and sensitivity. -Porcine and rat growth hormone, sera from cow, guinea pig, rabbit, mouse, and toad fish did not react with the guinea pig anti-HGH serum used in the assay. — In four patients after hypophysectomy, HGH concentrations disappeared almost completely, and in another patient no rise of the hormone was seen during an IV insulin tolerance test.-Undiluted human serum appears to produce falsely high levels of HGH. — Normal males exhibited fasting HGH levels from 0 –2.2 mg/ml (mean 0.8 mg/ml). Females ranged from 0.6–15.0 mg/ml (mean 5.1 mg/ml) and 15 acromegalics from 8.0–103.0mg/ml (mean 31.2 mg/ml). — During a rapid tolbutamide tolerance test, serum HGH rose between 2.5- and 82-fold over the fasting levels within 10 to 70 minutes following the glucose nadir.Performed in part during a postdoctoral fellowship Stiftung Volkswagenwerk, Germany.     

Iron stores in 1359, 30- to 60-year-old Danish women: Evaluation by serum ferritin and hemoglobin

Summary Iron status, including serum (S-)ferritin and hemoglobin (Hb), was assessed in a population survey comprising 1359 nonpregnant Danish women in age cohorts of 30, 40, 50, and 60 years. S-ferritin levels were similar in 30- and 40-year-old women; they displayed a significant increase in 50-year-old women and a further significant increase in 60-year-old women. In the 30- and 40-year-old women, median S-ferritin was 38g/l, 5–95 percentile 6–135g/l; 17.2% had values < 15,g/l (i.e., depleted iron stores), 22.7% values from 15 to 30g/l (i.e., small iron stores), and 60.1% values > 30g/l (i.e., replete iron stores). In the 50-year-old women, median S-ferritin was 54g/l, 5–95 percentile 10–164g/l; 10.3% had values < 15g/l, 16.5% values from 15 to 30g/l, and 73.2% values > 30g/l. For the 60-year-old women, median S-ferritin was 84g/l, 5–95 percentile 25–249g/l; 1.6% had values < 15g/l, 8.6% values from 15 to 30g/l, and 89.8% values > 30g/l. Blood donors (n=180) had lower S-ferritin than nondonors in all age-groups (p<0.001). In the entire series, Hb levels were similar in 30- and 40-year-old women, median 137 g/l (8.5 mmol/l), 5–95 percentile 121–152 g/1 (7.5–9.4 mmol/l), and higher in 50- and 60-year-old women, median 140 g/l (8.7 mmol/l), 5–95 percentile 123-158 g/l (7.6–9.8 mmol/l) (p<0.0001). Hb values < 121 g/l (7.5 mmol/l) were observed in 3.8% of the women. Women with S-ferritin < 15 g/l (n=161) had lower Hb, median 134 g/l (8.3 mmol/l), than those with S-ferritin > 15 g/l, median 139 g/l (8.6 mmol/l) (p<0.001). Iron deficiency anemia (S-ferritin < 15 g/l and Hb < 121 g/l) was seen in 2.3% of 30- and 40-year-old women, and in 1.1% of 50- and 60-year-old women.