Circadian esophageal motor function in patients with gastroesophageal reflux disease

Effective esophageal peristalsis is a major determinant of esophageal clearance function and may contribute to the development of complications in gastroesophageal reflux disease. Using 24-hour ambulatory esophageal manometry, we compared the circadian esophageal motor activity of normal volunteers to that of patients with increased esophageal exposure to gastric juice and various grades of mucosal injury (no mucosal injury, esophagitis, stricture, or Barrett's esophagus). The prevalence of a mechanically defective lower esophageal sphincter, esophageal acid exposure time, and the frequency of nonperistaltic esophageal contractions during the supine, upright, and meal periods increased with increasing severity of mucosal injury. The median amplitude of esophageal contractions was compromised only in patients with a mechanically defective sphincter. This was particularly so in patients with stricture or Barrett's esophagus and was associated with an increased frequency of ineffective contractions (less than 30 mm Hg). These data show that esophageal motor function deteriorates with increasing severity of mucosal injury. This appears to be caused by persistent reflux of gastric juice across a mechanically defective lower esophageal sphincter. The need for surgical correction of a mechanically defective sphincter before the loss of esophageal body function is implicated.     

Effect of propranolol on nitrogen and energy metabolism in sepsis

Pharmacologic therapy designed to block adrenergic activity or alter hormonal milieu may modulate energy and protein metabolism in stress. The metabolic effects of propranolol (beta adrenergic receptor blocker) in sepsis was investigated in 22 well-nourished rats that underwent superior vena caval cannulation, cecal ligation, and puncture. Animals were randomly assigned to receive either a continuous infusion of 0.7 mg/day of propranolol combined with parenteral nutrition (n = 11) or parenteral nutrition alone (n = 11). Both groups received isocaloric, isonitrogenous, isovolemic, parenteral nutrition post-operatively for 24 hr. Nitrogen balance was better for the propranolol group than for the control group (+743 +/- 84 mg/kg/day versus +300 +/- 63 mg/kg/day, respectively, P less than 0.05). A significant difference between the pharmacologic therapy and control groups was noted for urinary 3-methylhistidine excretion versus control (0.99 +/- 0.08 micrograms/kg/day versus 7.5 +/- 0.37 micrograms/kg/day, respectively, P less than 0.01). Measured energy expenditure was similar for both pharmacologic therapy and control groups (149 +/- 20 kcal/kg/day versus 134 +/- 11 kcal/kg/day, respectively, P = N.S.). No statistically significant difference was demonstrated for 24-hr survival between propranolol and control groups (73 and 64%, respectively). Continuous, low-dose propranolol promotes nitrogen retention and decreases 3-methylhistidine excretion without altering energy expenditure in parenterally fed septic rats.     

Trans-catheter closure of patent ductus arteriosus in childhood--an alternative to surgical ligature]

Transcatheter closure of a persistently patent ductus arteriosus (PDA) was successfully performed in four children using a Rashkind double disk umbrella device. Mean age was 5.1 +/- 1.5 (2.8 to 6.3 years) and weight 18.8 +/- 3.8 kg (14.1 to 22.3 kg). In all children the PDA was the only cardiac lesion and was diagnosed clinically and by means of continuous wave and color-coded doppler echocardiography. After angiographic measurement of PDA size the correlating device was implanted. The ductus was closed immediately in two children, whereas there was a residual angiographic shunt in the others. Echocardiography performed within 24 hours showed a minimal shunt only in one of these cases. The shunt had disappeared at the one month follow up study. We experienced none of the reported possible complications. Transcatheter closure of the PDA after the neonatal period seems to be a safe and effective alternative to surgical ligation as our early experience shows, and should become the procedure of first choice in these patients.     

Lack of effect of paracetamol on the pharmacokinetics of chloramphenicol.

The effect of oral paracetamol (1 g) on the pharmacokinetics of oral chloramphenicol (500 mg) was examined in five adult male Zimbabwean patients with normal hepatic and renal function. No significant alteration of half-life, area under the concentration-time curve or peak concentration of chloramphenicol was observed. The previously reported, potentially serious interaction between chloramphenicol and paracetamol administered intravenously was not observed with the more commonly used oral preparations.     

The significance of HIV antigen and HIV antibodies specific against envelope and core proteins in serum of HIV-infected hemophiliacs

Serial serum samples from the 21 HIV-infected Norwegian hemophiliacs have been assayed for the presence of HIV antigen and antibodies to HIV specific for the core protein p24 and the envelope protein gp41. HIV antigen was detected in 4 patients, of whom 3 have developed AIDS to date. HIV antigen appeared in serum 10 to 24 months before the diagnosis in these patients. Antibodies to gp41 was a constant finding. Antibodies to p24 disappeared from the serum in 1 patient who developed AIDS and from 3 persons free of symptoms related to the HIV infection. The detection of HIV antigen in HIV antibody-positive hemophiliacs appears to be of considerable prognostic significance.     

Multiple sclerosis and the workplace: report of an industry-based cluster

Eleven cases of MS occurred within a 10-year period in a zinc-related manufacturing plant. The observed disease incidence was greater than expected from population data, using multiple approaches to statistical analysis (p less than or equal to 0.01). A case-control study, performed to examine several zinc parameters in blood, failed to indicate specific abnormalities among the MS patients, but all subjects (both MS and controls) working in the plant demonstrated higher serum zinc levels than all subjects (MS and controls) not working there.     

Complex pharmacological properties of recombinant alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionate receptor subtypes.

The pharmacological properties of two glutamate receptor subtypes, GluR-A/B and GluR-B/D, were examined in RNA-injected Xenopus oocytes using two-electrode voltage clamp. Concentration-response relations revealed that the potencies of L-glutamate, kainate, and alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionate (AMPA) varied slightly between the two receptor subtypes, but the rank order of agonist potency did not. The EC50 values for GluR-A/B receptors were 3.31 microM for AMPA, 6.16 microM for glutamate, and 57.5 microM for kainate, whereas the EC50 values for GluR-B/D receptors were 5.01 microM, 32.3 microM, and 64.6 microM for AMPA, L-glutamate, and kainate, respectively. The potencies of 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX) and 2,3-dihydroxy-6-nitro-7-sulfamoyl-benzo(f)quinoxaline (NBQX) were quantified by Schild analysis. The potency of NBQX at blocking currents mediated by GluR-A/B receptors changed depending on the agonist used to activate the receptors (pA2 values were as follows: for block of kainate, 7.23 +/- 0.01; L-glutamate, 6.78 +/- 0.02; AMPA, 6.95 +/- 0.02). Differences between agonists were less marked in cells expressing GluR-B/D receptors (pA2 values: kainate, 7.28 +/- 0.01; L-glutamate, 7.30 +/- 0.02; AMPA, 7.35 +/- 0.01). In each case, the slope of the Schild regression was not different from unity, consistent with competitive antagonism of these receptors by NBQX. CNQX also blocked GluR-A/B and GluR-B/D receptors competitively but was less potent than NBQX and did not differentiate between agonists or subunit combination. These data suggest that L-glutamate, kainate, and AMPA bind to different receptor substructures on recombinant AMPA receptors and that NBQX but not CNQX binds to these sites with different affinities. Moreover, because the properties of these binding sites vary between GluR-A/B and GluR-B/D receptors, our findings provide a basis for mutational analysis aimed at identifying receptor domains involved in agonist and antagonist binding.     

Interobserver variability in neonatal cranial ultrasonography

The reliability of cranial ultrasound diagnosis in the premature neonate was examined using data from an ongoing multicentre study of the epidemiology and long-term consequences of neonatal brain haemorrhage. First week ultrasound films (obtained at 4 hours, 24 hours and 7 days) from 60 study subjects were randomly selected for independent review by two groups of experienced interpreters, and results were recorded separately for observations (i.e. presence or absence of an abnormal echodense area on a film) and interpretations (i.e. presence or absence of haemorrhage or ventricular dilatation) in each hemisphere. Because of deaths in the first week of life, the total number of films examined was 138. Concordance on the presence or absence of an abnormal echodensity was examined for each individual film for three areas of interest: the germinal matrix, the ventricles and the parenchyma. Concordance on the presence or absence of haemorrhage or ventricular dilatation was examined only for the seventh-day film, or the final film prior to death. Finally, concordance was analysed with the diagnostic interpretations grouped into categories thought to differ prognostically for long-term outcome. In general, concordance was poorest for germinal matrix lesions and best for parenchymal lesions. Concordance was lower for observations made on each individual film than it was for interpretation of the final film in each case. Fifty-five of 60 cases (92%) were assigned to the same major prognostic category by both readers. Ultrasound review conferences were held periodically and there was evidence that concordance in ultrasound reading and interpretation improved during the course of the study.