Permeability of single muscle capillaries to potassium ions

A frog muscle preparation suitable for capillary micropuncture is described. The K⁺ permeability of single muscle capillaries was measured using the methods developed for frog mesenteric capillaries (C. Crone, J. Frøkjaer-Jensen, J. J. Friedman, and O. Christensen (1978), J. Gen. Physiol.71, 195–220). The K⁺ permeability of arterial capillaries was 8.6 × 10^?5 cm/sec (SD = 1.8; n = 7). The initial K⁺ permeability of venous capillaries was 13.1 × 10^?5 cm/sec (SD = 4.3; n = 6). In venous capillaries—unlike in arterial capillaries—a gradual increase in permeability associated with endothelial gap formation was observed in repeated measurements on the same capillary segment. This inflammatory response to exposure, micromanipulation, or perfusion could be partially blocked by pretreatment with promethazine. The study shows that frog muscle capillaries differ markedly from frog mesenteric capillaries, being 5–10 times less permeable to potassium ions although both belong to the category of continuous capillaries. The results demonstrate that whole-organ and single-capillary techniques for studying muscle capillary permeability yield values which comply within a factor of about 2.     

Motor nerve conduction velocity in asymptomatic lead workers

Summary No difference was found between the nerve conduction velocities of the ulnar nerve of 32 lead exposed workers in the mill of a lead-zinc mine, compared to that of a control group of 14 persons. The lead exposure period was 2–37 months (mean: 12.9 months).The blood lead of the exposed group was as an average (± SD): 53 ± 16 g per 100 ml compared to 11 ± 4 g per 100 ml for the control group.Further studies are needed to establish a possible dose-time-response relationship for the possible, subclinical neuropathy found by some investigators.     

Pharmacokinetics of a single oral dose of muzolimine in cardiac failure

Summary The pharmacokinetics of a new high ceiling diuretic, muzolimine (Bay g 2821), were investigated after a single oral dose of 40 mg in 7 patients with cardiac failure (Stages I–IV, New York Heart Association classification), and in 2 healthy subjects. Plasma concentrations peaked 1–3 h after administration and declined according to a two-compartment model. The -phase (distribution phase) lasted until 12–16 h after administration and the mean t_1/2 was 3.6 h (range 2.3–4.7) in patients, and 2.6 h (range 2.3–2.9) in healthy subjects. The mean t_1/2 was 13.5 h (range 7.4–22.4) in the patients and 14.0 h (range 12.4–14.6) in healthy subjects. T_1/2 was not correlated with the degree of heart failure or with the area beneath the plasma concentration curve, which varied three-fold. The renal clearance of muzolimine was in the range 2.7–15.3 ml · min^–1 in 5 subjects in whom it was investigated. The pharmacokinetics of muzolimine appear not to be significantly altered by cardiac failure. The prolonged half-lives of the drug are probably responsible for the longer duration of diuretic action reported for muzolimine than for furosemide and bumetamide.     

Behavioral effects of low,acute doses of d-amphetamine on the dyadic interaction between mother and infant vervet monkeys (Cercopithecus aethiops) during the first six postnatal months

Doses of d-amphetamine sulfate (0.1, 0.15, and 0.2 mg/kg body weight) were given to adult monkeys in mother—infant pairs. The fundamental parental care behavior pattern was disrupted and the mother became isolated in a socially withdrawn phase. She did not respond to the calling signals of the infant and showed behavior in which stereotyped self-grooming and/or staring into space were predominant. The reactions of the infant to this amphetamine-induced behavior were different in the two experimental pairs. In group 1 the infant increased its approach—avoidance movements. In group 2 the infant sat very quietly and close in front of the mother. The mother from group 1 reacted to the increased approaches from its ininfant with active rejection. In both groups the mothers did not react with the typical ventral—ventral grasping to either the infants sitting close or to the social anxiety signals of the infants. In spite of differences in behavior changes induced by amphetamine, the main conclusion is that the mothers totally lost their normal and highly biologic significant interest in their infants.     

Steady-state kinetics of imipramine in patients

Steady-state plasma level kinetics were studied in 76 patients given imipramine (IP) 150 to 225 mg/day for 2–5 weeks. IP was given in three divided doses at 8.00 a.m., 1.00 p.m. and 5.00 p.m. Plasma concentrations of IP and its active metabolite desipramine (DMI) were determined by quantitative in situ thin-layer chromatography. The plasma levels of IP and DMI showed pronounced flucutations throughout the day with a ratio of about 2 between highest and lowest level. Patients with steady-state levels of IP and/or DMI below 50 g/l reached this within 1 week of treatment. Patients with higher steady-state levels reached steady-state concentrations within 2–3 weeks. There were some intraindividual fluctuations in plasma levels from week to week after steady state had been reached (coefficient of variation: 10–20%). Interindividually, the steady-state levels corrected to a dose of 3.5 mg/kg per day varied considerably: IP: 6–356 g/l, DMI: 24–659 g/l and IP+DMI: 58–809 g/l. The steady-state plasma levels showed a skew distribution that became normal by logarithmic transformation. The IP/DMI ratio ranged from 0.07 to 5.5 with a median value of 0.47. Compared to data from amitriptyline treated patients the IP/DMI ratios had significantly lower median value and larger variation than the corresponding plasma level ratios of amitriptyline/nortriptyline. Several statistically significant differences in steady-state levels between age groups were found. For IP: Women aged 30–39 had lower levels than women aged 20–29, 40–49, and 50–59, and men aged 50–59 and 60–65; men aged 30–39 had lower levels than men aged 60–65. For DMI: Women aged 30–39 had lower levels than women aged 50–59.     

Effect of short-term hyperventilation on cerebral blood flow autoregulation in patients with acute bacterial meningitis

BACKGROUND AND PURPOSE: Cerebral blood flow (CBF) autoregulation is impaired in patients with acute bacterial meningitis: this may be caused by cerebral arteriolar dilatation. We tested the hypothesis that CBF autoregulation is recovered by acute mechanical hyperventilation in 9 adult patients with acute bacterial meningitis. METHODS: Norepinephrine was infused to increase mean arterial pressure (MAP) 30 mm Hg from baseline. Relative changes in CBF were concomitantly recorded by transcranial Doppler ultrasonography of the middle cerebral artery, measuring mean flow velocity (V(mean)), and by measurement of arterial to jugular oxygen content difference (a-v DO(2)). The slope of the regression line between MAP and V(mean) was calculated. Measurements were performed during normoventilation and repeated after 30 minutes of mechanical hyperventilation. RESULTS: At normoventilation (median PaCO(2) 4.4 kPa, range 3.5 to 4.9), MAP was increased from 68 mm Hg (60 to 101) to 109 mm Hg (95 to 126). V(mean) increased with MAP from 48 cm/s (30 to 61) to 65 cm/s(33 to 86) (P<0.01), and a-v DO(2) decreased from 2.2 mmol/L (1.0 to 2.7) to 1.4 mmol/L (0.8 to 1.8) (P<0.05). During hyperventilation (PaCO(2) 3.5 kPa, range 3.3 to 4.1), MAP was increased from 76 mm Hg (58 to 92) to 109 mm Hg (95 to 121). V(mean) increased from 45 cm/s (29 to 55) to 53 cm/s (33 to 78) (P<0.01), and a-v DO(2) decreased from 2.5 mmol/L (1.8 to 3.0) to 1.8 mmol/L (1.2 to 2.4) (P<0.05). Four patients recovered autoregulation completely during hyperventilation. The slope of the autoregulation curve decreased during hyperventilation compared with normoventilation (P<0.05). CONCLUSIONS: CBF autoregulation is partially recovered during short-term mechanical hyperventilation in patients with acute bacterial meningitis, indicating that cerebral arteriolar dilation in part accounts for the regulatory impairment of CBF in these patients.     

Apoliprotein E and multiple sclerosis: impact of the epsilon-4 allele on susceptibility, clinical type and progression rate

The purpose of this study was to investigate the relation between APOE genotype and Multiple Sclerosis (MS) in a genetically homogeneous population. We examined 240 patients consulting the MS-clinic during a period of 3 years (1996 - 1999). The mean age of the patients was 41.7 years (range 19 - 80 Y, SD 10.0 Y). As a measure of the progression rate (PR) the last registered Expanded Disability Status Scale (EDSS) score was divided by the time span (years) from disease onset until the latest assessment. The APOE genotype was determined from saliva and/or blood samples using PCR-techniques. The prevalence of different APOE genotypes was compared with the allele-distribution in a population of 361 persons from a Danish cross-sectional population study. The frequency of APOE-epsilon 4/epsilon 4 homozygotes was significantly higher in the MS-group as compared to controls (P<0.05, odds ratio: 2.3), whereas the frequency distribution of other genotypes did not differ significantly. The rate of progression was significantly faster in the APOE-epsilon 4/epsilon 4 homozygotes compared to other genotypes in the MS group (P<0.05). This study suggests that the APOE-epsilon 4/epsilon 4 homozygotes have an increased risk of developing MS. MS patients with the APOE-epsilon 4/epsilon 4 allele may also have an increased rate of disease progression. Multiple Sclerosis (2000) 6 226 - 230     

Muscular Performance and Fatigue in Primary Hyperparathyroidism

The purpose of this study was to evaluate changes in muscular strength and endurance, work capacity, and subjective fatigue following surgical treatment of primary hyperparathyroidism (pHPT), and to assess whether changes in muscular function were due to changes in activation of the muscles. A prospective consecutive study design was used, and patients surgically treated for nontoxic goiter served as controls. Nineteen female patients with mild to moderate pHPT and 20 controls were included. Maximal isometric handgrip and quadriceps strength, quadriceps endurance (intermittent stimulation), and quadriceps activation (superimposed twitch technique) were used for evaluation of muscular function. All patients were operated on successfully. Knee extension strength increased by 17 ± 17% (mean ± SD; p= 0.0004) in the patients, whereas no change was observed in the controls. The relative strength increase correlated positively to patient age at operation (r= 0.52, p= 0.02). Handgrip strength, quadriceps endurance, and general work capacity did not change in any group after operation. Subjective fatigue was preoperatively higher in patients than in controls (p= 0.01), and decreased postoperatively to the level of controls. In conclusion, women with pHPT increase knee extension force after parathyroidectomy as a result of increased force generation capacity of the muscle. If change in physical performance is a determinant for change in subjective fatigue in pHPT after operation, then change in strength of the quadriceps muscle seems to be of primary importance, whereas handgrip strength, muscular endurance, and work capacity do not seem to be important. The cause of the increasing strength benefit with increasing age at operation as found in this study needs further investigation.     

Madelung deformity treated with Ilizarov technique: a report of two cases

Two children with painful and progressive Madelung deformities were treated by osteotomy of the radius and subsequent angular correction and bone lengthening using the Ilizarov technique. Both children were radiologically improved and free of pain at follow-up.