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Biomedical subjects

M Hall

Publications and source records attributed to M Hall.

At least 307 records · Page 17Linked to original sources

The effects of opioid drugs and of lithium on steroidogenesis in rat adrenal cell suspensions.

1. The effects of opioid drugs and of Na+ replacement on steroidogenesis in rat adrenal cell suspensions were investigated. 2. In medium containing normal Na+ (156 mM), opioid antagonists but not opioid agonists reduced the steroidogenic response to adrenocorticotrophic hormone1-24 (ACTH1-24) but not to dibutyryl adenosine 3',5' cyclic monophosphate (db cyclic AMP). 3. Replacement of 50% Na+ in the medium by choline had no effect on steroidogenesis, but further reductions in Na+ content reduced the steroidogenic activity of both ACTH1-24 and db cyclic AMP. 4. In 50% Na+ medium both opioid agonists and antagonists inhibited ACTH1-24 induced steroidogenesis. 5. Addition of therapeutic concentrations of lithium to otherwise normal medium inhibited the steroidogenic response to ACTH1--24 but not to db cyclic AMP. 6. The selective inhibition of ACTH1--24-induced steroidogenesis by opioid drugs suggests some similarity between the opioid and ACTH receptors. 7. The relevance of the potent inhibitory effect of lithium to its therapeutic actions is discussed.

Adrenal Glands↗

The effect of intracerebroventricular administration of methionine-enkephalin on the stress-induced secretion of corticosterone in mice.

Ether stress or intracerebroventricular (i.c.v.) administration of saline, met-enkephalin, or naltrexone raised plasma corticosterone levels in mice. The response to ether stress was abolished by a preceding ether stress or by pretreatment with i.c.v. saline or naltrexone. However, following i.c.v. met-enkephalin, plasma corticosterone was significantly elevated by ether stress, the effect being blocked by simultaneous injection of met-enkephalin and naltrexone. Met-enkephalin appears to prevent fast-feedback inhibition of the hypothalamus-pituitary-adrenal system.

Animals↗

The effects of opiate receptor agonists and antagonists on the stress-induced secretion of corticosterone in mice.

1 Intraperitoneal administration of normorphine, morphine or naloxone or exposure to ether vapour for 1 min, elevated plasma corticosteroid concentrations in mice. 2 Injection of saline or exposure to ether vapour rendered mice less sensitive to a subsequent exposure to ether vapour 15 min later. 3 Treatment with normorphine (50 mg/kg) potentiated the corticosteroid response to ether stress whilst pentazocine (20 mg/kg), naltrexone (10 mg/kg), morphine (24 mg/kg), levorphanol (20 mg/kg) and naloxone (50 mg/kg) prevented the stress-induced elevation of plasma corticosteroids. 4 Both naloxone and morphine inhibited the potentiation by normorphine of the response to ether, the dose of naloxone required being higher than that for inhibition of normorphine analgesia. 5 It is concluded that endogenous opioid peptides may be involved in the control of the response to ether stress in mice.

Analgesia↗

Naproxen in juvenile chronic polyarthritis.

Naproxen at 10 mg per kg body weight was compared with aspirin at 80 mg per kg body weight in children suffering from juvenile chronic polyarthritis. It was found to be as effective as aspirin, with certainly no more and possibly fewer gastrointestinal side effects. A long-term tolerance study up to 12 months confirmed that naproxed was a satisfactory nonsteroidal anti-inflammatory drug in the management of various types of juvenile chronic arthritis.

Adolescent↗

The gravity suit: a major advance in management of gynecologic blood loss.

We have used the gravity suit (G-suit) to stabilize patients in shock as a result of ruptured ectopic pregnancies. Four patients presenting in shock were carefully studied with serial vital signs, fluid replacement, and blood loss before and after application of the G-suit. These studies were continued through surgery and the removal of the G-suit. The G-suit improved vital signs, increased peripheral organ and limb perfusion, and decreased blood loss in all cases.

Adult↗

The premature breech: trial of labor or cesarean section?

Sixty-six premature breech deliveries were studied retrospectively. Forty-eight patients were permitted a trial of labor, 47 of whom ultimately delivered vaginally. Eighteen patients underwent cesarean section as soon as possible after their arrival at the delivery suite. When Apgar scores, perinatal mortality rates, cord prolapse, and entrapment of the aftercoming head are considered, cesarean section is probably the safer course of management for the patient with a footling breech infant, especially when the infant weighs 1500 g or less. However, the data indicate that a trial of labor can be safely undertaken in the presence of a premature frank or complete breech presentation.

Anesthesia, Obstetrical↗

Meconium passage: a new classification for risk assessment during labor.

The significance of MSAL as a sign of fetal distress is controversial. To better assess this condition, we present a classification of MSAL based on the timing and quantity of meconium passed and divided into early light, early heavy, and late passage of MSAL. By means of this classification with a problem-oriented risk assessment system, 2,933 pregnancies were prospectively evaluated during labor. The incidence of meconium passage was 22 per cent, of which early light constituted 53.6 per cent, early heavy 25.2 per cent, and late passage 21.2 per cent. Early heavy MSAL is associated with increased fetal and neonatal morbidity and death, and with a number of antecedent obstetric problems. Late passage of MSAL encountered no perinatal losses, but is associated with increased neonatal morbidity occurring late in labor. Early light MSAL, constituting over half of all our meconium group of patients, is not associated with any increased intrapartum or neonatal morbidity or death. This classification of MSAL is an effective tool for risk assessment during labor.

Amniotic Fluid↗

Yellow-brown spindle bodies in mesenteric lymph nodes: a possible relationship with melanosis coli.

Four cases are described in which spindle-shaped, yellow-brown bodies were seen in the mesenteric lymph nodes of patients with melanosis coli. A comparison of the staining reactions and ultrastructural appearances of the spindle bodies and melanosis pigment suggest that they are related within the broad group of lipofuscins and that the spindle bodies are formed as a result of coalescence of lysosomes containing the pigment.

Adenocarcinoma↗

Blue naevus of the cervix: report of two cases and review of the literature.

Two cases are described of blue naevi occurring in the uterine cervix. These showed a histological appearance identical to that seen in the commoner cutaneous examples. Electron microscopy of both lesions showed the presence of melanosomes in the dendritic cells. No Schwann cell elements were identified. Previous reports of cases are reviewed and discussed.

Cervix Uteri↗

Evaluation of a routine anaerobic subculture of blood cultures for detection of anaerobic bacteremia.

The value of a routine 48-h anaerobic subculture of blood cultures was assessed in our laboratory over a 4-month period. Excluding presumed contaminants, anaerobes represented 51 (6.9%) of the total number of 734 positive cultures. Sixteen isolates (all Bacteroides) from six patients were detected by the anaerobic subculture. All but one of these were also detected macroscopically. Excluding the one isolate, the routine anaerobic subculture hastened the identification of anaerobic organisms by only 1 day in two patients. We conclude that a routine anaerobic subculture is not indicated for the detection of anaerobic bacteremia.

Anaerobiosis↗

Cleavage planes in the envelope of Aquaspirillum bengal.

The cell surface of Aquaspirillum bengal was devoid of superficial wall structure. When cells were freeze-cleaved and etched, multiple fracture planes through the cell envelope were exposed, which was unusual for an aquaspirillum. These included both convex and concave surfaces and they are compared with those of other gram-negative bacteria.

Cell Wall↗

Metabolsim of apoB and apoC lipoproteins in man: kinetic studies in normal and hyperlipoproteininemic subjects.

The kinetics of apolipoproteins B and C were studied in 14 normal and hyperlipoproteinemic subjects after injection of exogenously (125)I-labeled very low density lipoprotein (VLDL) particles. Plasma radioactivities of apoB and apoC were determined over a period of 4 days in VLDL (d < 1.006) and total radioactivity in intermediate (IDL) (1.006 < d < 1.019), low (LDL) (1.019 < d < 1.063), and high (HDL) (1.063 < d < 1.21) density lipoproteins. The data were analyzed by the use of a model, developed mostly from these data, with the following results. The VLDL particle undergoes a series of incremental density changes, most likely due to a number of delipidation steps, during which apoB stays with the particle until the density reaches the IDL range. There is, however, a loss of apoC associated with these delipidation steps. In our normal subjects, all IDL apoB eventually becomes LDL. In our hyperlipemic subjects some of the apoB on IDL is also degraded directly. The apoC lost by VLDL and IDL recycles to HDL, and most of it is picked up again by newly synthesized VLDL. There is a slowdown of the stepwise delipidation process in all hyperlipemic individuals studied. Three additional features became apparent in the type III subjects. First, there is a significant increase (a factor of 2 compared to normal) in the apoB synthesis rate by way of VLDL; second, there is an induced direct apoB synthesis pathway by way of IDL (and/or LDL); third, a bypass of the regular stepwise VLDL delipidation pathway is induced by which VLDL particles lose apoC but none of their apoB, thereby forming a new particle with metabolic properties similar to LDL, but with a density still in the VLDL density range. Two type III patients treated with nicotinic acid and clofibrate showed a sharp decrease in their VLDL apoB synthesis rates. This was somewhat compensated by an increased IDL apoB synthesis rate. A type I patient on a medium chain triglyceride diet also showed a number of metabolic changes, including reduced VLDL apoB synthesis and the induction of considerable IDL and/or LDL apoB synthesis.

Adult↗