Biomedical subjects
Publications and source records attributed to J Walker.
Oestrogen depress [3H]-mepyramine binding in the amygdala, hypothalamus and cerebral cortex of rats. These effects of oestrogens are prevented by concurrent administration of inhibitors of cyclic 3'5' AMP phosphodiesterase, suggesting that the hormones act by reducing the activity of adenylate cyclase.
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In January 1983, the New York City Department of Health initiated an active surveillance program for acquired immunodeficiency syndrome (AIDS) in 19 hospitals and a modified-active surveillance program in the remaining 69 hospitals. We reviewed hospital laboratory and autopsy records in 12 active surveillance hospitals and three modified-active surveillance hospitals six months later. Patients who had opportunistic diseases characteristic of AIDS diagnosed in 1982 (before active surveillance) and 1983 (after implementation of active surveillance) were matched against health department AIDS surveillance reports. For the 16 months we evaluated, 96% of patients identified with AIDS in the 12 active surveillance hospitals and 100% of those in the three modified-active surveillance hospitals had been reported to the health department. The delay between diagnosing a case and reporting it to the health department significantly decreased between 1981 and the first six months of 1983 in all hospitals. The proportion of cases reported within one month of diagnosis increased from 45% to 69% during this period. We conclude that the current surveillance program for AIDS in New York City is effective and that case reporting is sufficiently complete for accurate analysis of disease trends.
Fifteen patients with chronic malignant intractable pain were given epidural narcotics for periods of up to 280 days. The majority were treated at home. The patients self-administered the narcotics through an indwelling epidural catheter that had been tunneled and brought out onto the anterior abdominal wall. The results are presented together with the problems encountered.
Sixteen consecutively-born monkeys were used in a longitudinal study to determine the changes occurring in the total number of bacteria in the palatal grooves of the upper left first deciduous molar teeth, following the introduction of a sucrose-based diet. The total number of bacteria recovered from the grooves increased significantly following the diet change. Twenty-nine days after the diet change, the number of Streptococcus mutans had increased from a median value of less than 10(2) to approx. 10(7) per groove, and the number of Streptococcus sanguis decreased. These changes in the number of Strep. mutans occurred prior to the detection of dental caries. Grooves that became carious harboured significantly more bacteria and more Strep. mutans than did grooves remaining caries-free six months after the diet change.
Morphine (M) produced a dose-related decrease in metabolic weight loss (MWL) over a three-hour period, despite the fact that it significantly enhanced locomotor activity in male mice. This conservation of energy was specific to opioid receptors because naltrexone HCl (N) blocked it. These receptors were localized mainly to the periphery because a form of N that does not enter the brain, MR2663 BR (QN) eliminated the conservation response and instead increased MWL. The increase in MWL induced by M plus QN was blocked by MR2266 (MR), a specific kappa receptor antagonist. We suggest that this increase is due to the unmasking of a kappa opioid system located in the brain that acts to enhance energy expenditure. In support of this idea, administration of the kappa receptor agonist U-50,488H (U) produced a dose-related increase in MWL to levels nearly twice that of saline controls, while markedly reducing locomotor activity. These actions were blocked by MR but not by N. They were not blocked by QN and this suggests they originate mainly in the brain. Increasing amounts of M caused increasing inhibition of metabolic weight loss induced by a constant amount of U. This supports the idea of an antagonistic relationship between the two opioid systems.
The present study explored the factors that contribute to mothers' decisions to seek urgent medical attention for their children when symptoms are not of a traumatic nature. One hundred mothers seeking treatment for their children at a prepaid clinic completed a questionnaire eliciting their expectations regarding the course of their children's problems, seriousness of the problems, perceived responsibility for the symptoms, and extent to which a variety of factors contributed to their decisions to seek treatment. Demographic data and information about each child's symptoms and medical history were also obtained. Four major "reasons for seeking treatment" factors were identified: family history of the presenting complaint, worry regarding the symptoms, situational variables, and the extent of the child's illness behavior. The appropriateness of the visit, delay in seeking treatment, and frequency of mothers' use of the pediatric clinic were predicted by the nature of the presenting symptoms (particularly the presence of fever), the ages of the mother and child, and two of the reasons for seeking treatment factors (i.e., family history and child's illness behavior). The present study suggests that mothers pay more attention to presenting symptoms and to the children's behavior than to psychosocial stressors in deciding to seek urgent care.
Rats exposed to inescapable shock exhibited analgesia and a significant impairment of shock-escape learning in a shuttle box situation 24 hr later. In contrast, rats exposed to escapable shock or to no shock displayed neither effect. Naltrexone (10 mg/kg) significantly reduced the analgesia and completely eliminated the escape deficit in inescapably shocked rats but induced hyperalgesia, coupled with a marked deterioration of escape performance, in escapably shocked and nonshocked rats. The same dose of quaternary naltrexone, which has low ability to cross the blood-brain barrier, had no effect on either the antinociception or the escape deficit produced by inescapable shock, although it also induced escape impairment and hyperalgesia in rats preexposed to escapable shock or to no shock. A second experiment demonstrated that both the escape interference and the antinociceptive consequences of prior inescapable shock could be reduced partially by a much lower dose (1 mg/kg) of naltrexone but 50 times this amount of quaternary naltrexone was still without effect. These results imply that the consequences of exposure to inescapable shock are mediated by activation of central opioid processes whereas naltrexone-induced effects in escapably shocked and nonshocked animals may be peripherally mediated. The relevance of these findings to the possible role of nociception in escape performance is discussed.
A microcomputer system is described for the collection, analysis and printing of the physiological data gathered during a urodynamic investigation. Examples are given of the results obtained from such a system.
Thyroid ultrasound differentiates solid from cystic lesions, solitary nodules from multinodular and diffuse enlargement, and extrathyroidal lesions. Two hundred consecutive patients with a clinically solitary thyroid nodule were investigated by ultrasound examination, thyroid function test, and thyroid auto-antibodies. Patients with confirmed solitary solid, or mixed solid and cystic nodules underwent surgery as well as those with cysts, multinodular or diffuse goitres with pressure symptoms, recurrent haemorrhage or relapsing hyperthyroidism. Comparison between the ultrasound and ultimate pathological findings in the 101 patients who underwent surgery showed that they were in agreement in 96 cases. The remaining 99 patients with cystic, multinodular or diffuse lesions have been followed up for a mean of two years. Nearly 50% of patients with a clinically solitary thyroid nodule have avoided surgery.
Whole kidney and renal micropuncture techniques were used to investigate the effects of chronic prolactin treatment on kidney function in anaesthetized female rats. At the whole kidney level, glomerular filtration rate (GFR) and fluid reabsorption were both significantly (P less than 0.02) increased in the hormone-treated group. At the single nephron level, GFR and proximal fluid reabsorption were also increased (P less than 0.05) by prolactin treatment. Fractional reabsorption was also enhanced at the proximal tubular level in hormone-treated animals. Such changes in renal function are similar to those seen in rat pregnancy and cervically stimulated pseudopregnancy. Since circulating prolactin concentrations are increased in both reproductive states, the hormone may play an important role in establishing the characteristic renal changes seen therein.
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The potent opioid peptide dynorphin (DYN) is found in posterior pituitary vasopressinergic neurones and in adrenal medullary cells suggesting that secretion into plasma is likely. We have developed a sensitive radioimmunoassay in order to study plasma DYN in man. It transpired that extraction prior to assay was essential since unextracted plasma caused gross and non-parallel inhibition of binding of tracer. Plasma extracted using leached silica glass ( Vycor ) caused inhibition of tracer binding which diluted in parallel to synthetic DYN suggesting the presence of substantial amounts of DYN-like immunoreactivity ( irDYN ) in plasma. Further investigation however demonstrated that this irDYN was artifactual and caused by enzymatic degradation of tracer. Although use of Seppak C18 cartridges resulted in reliable extraction of synthetic porcine DYN from acidified plasma, we have not detected irDYN in any plasma so far studied using this technique. However, extraction of non-acidified plasma using our antibody coupled to Sepharose CNBr-activated 4B followed by gel filtration chromatography demonstrated a single peak of irDYN of molecular size similar to DYN. These data suggested that a small amount of a DYN-like peptide does circulate in human plasma although this is not identical to porcine DYN(1-17). The implication of our results for the measurement of other similar peptides in plasma is discussed.
A 17-year-old boy with spastic quadriplegia presented with a progressively enlarging, tender, right inguinal mass. Examination revealed absence of both testicles in the scrotal sac. The left testicle was palpable in the left superficial inguinal pouch. A diagnosis of an undescended right testicle was confirmed by exploratory surgery. Orchidectomy of the right testicle was performed and the remainder of the patient's course was uneventful. We present this case to describe the relationship between cryptorchidism, testicular torsion, and neuromuscular disease. Specific emphasis is placed on incidence, pathophysiological mechanisms, and treatment of testicular torsion in cryptorchidism.
Reference intervals for some clinical chemistry parameters in the marmoset were calculated. The effects of age (250-300 days compared with 500-550 days) and sex on the values found was investigated. Alkaline phosphatase levels decreased with age, young males having higher plasma levels than young females, but no sex differences were discernible for older animals. Levels of gamma-glutamyl transpeptidase and sorbitol dehydrogenase were higher in older males than in younger females. Higher plasma iron levels were found in the males with increasing age. Age and sex effects for protein and albumin were interactive and further interpretation was therefore difficult. No significant age or sex effects were seen for cholinesterase, acetylcholinesterase, isocitrate dehydrogenase, malate dehydrogenase, lactate dehydrogenase, glutamate dehydrogenase, aspartate amino transferase, alanine aminotransferase or bilirubin.