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Biomedical subjects

M Bell

Publications and source records attributed to M Bell.

At least 181 records · Page 10Linked to original sources
PubMed1985

Comparison of artificial light sources and lighting programmes for laying hens on long ahemeral light cycles.

Three lighting treatments were given to laying hens, for which the bright and dim light of 28-h ahemeral light cycles was provided by incandescent (tungsten filament) lamps only or by combinations of tubular fluorescent or compact gas-discharge lamps with incandescent lamps. There were no differences in entrainment (the proportion of eggs laid in 4, 6 or 8 h modal periods) between the three bright:dim treatments. A fourth ahemeral lighting treatment in which the dim lights were extinguished except during a designated work period (09.00 h to 12.00 h daily) was termed bright:dim:dark. Hens given the bright:dim:dark treatment showed an increased entrainment compared with the three bright:dim light treatments. There were no differences (P greater than 0.05) in egg numbers or mean egg weight between all 4 lighting treatments. Birds given the bright:dim:dark treatment tended to have a lower (P greater than 0.05) food intake compared to the three bright:dim treatments.

Animals↗
PubMed1985

Effect of hyperglycemia and its prevention by insulin treatment on the incorporation of 32P into polyphosphoinositides and other phospholipids in peripheral nerve of the streptozotocin diabetic rat.

The influence of varying doses of streptozotocin and preventive insulin treatment on phospholipid metabolism in sciatic nerve in vitro from diabetic rats was studied. Animals were given 30, 45, and 60 mg/kg injections of streptozotocin and 10 weeks later nerves were removed and incubated in the presence of [32P]-orthophosphate. The quantity of isotope incorporated into phosphatidylinositol-4,5-bisphosphate (PIP2) was progressively greater with increasing drug dosage, whereas uptake of label into other phospholipids was unchanged. Rats were made diabetic and within 72 h were implanted with long-acting, insulin-containing osmotic minipumps and the incorporation of [32P]orthophosphate into phospholipids of intact and epineurium-free nerves was examined 8 weeks later. For whole nerve, increased labeling in nerves from diabetic animals occurred only in PIP2 and phosphatidylinositol-4-phosphate (PIP) and was completely prevented by insulin treatment. Isotope incorporation into polyphosphoinositides was also markedly elevated (greater than or equal to 100%) in desheathed diabetic nerves, but not in nerves from insulin-treated animals. Other phospholipids in epineurium-free nerves displayed some rise in isotope uptake, but the increases were not prevented by insulin treatment and appeared unrelated to hyperglycemia. Morphological examination of nerves extended previous findings that prolonged insulin treatment produces axonal degeneration. These observations indicate that abnormal nerve polyphosphoinositide metabolism is at least in part a consequence of hyperglycemia. The metabolic alterations may be intimately involved in reduced nerve conduction velocity, which is characteristic of diabetic neuropathy.

Animals↗
PubMed1985

Patient flow patterns in a recovery room and implications for staffing.

A detailed analysis of the occupancy of a new recovery room in a small district general hospital was undertaken during the initial three months of its use. The main problems were found to be irregular workload, consistently high patient occupancy over lunchtime, and difficulty in matching traditional nursing shifts to periods of heavy workload.

Bed Occupancy↗
PubMed1984

Learned helplessness: effects on brain monoamines and the pituitary-gonadal axis.

The effect of the learned helplessness paradigm, a model of depression, on biogenic amines in eight brain regions, and on the serum levels of luteinizing hormone, corticosterone, and testosterone in male rats was determined. Rats which were exposed to uncontrollable and unpredictable shocks (HY-rats) had hormone levels similar to those in appropriate control animals. However, HY-rats had higher levels of 5-HIAA in the pons/medulla oblongata and lower levels of 5-HT in the cortex than rats which could escape the shocks (HE-rats). Furthermore, striatal levels of NE were higher in HY-rats when compared to HE-rats and non-shocked controls (HC-rats). Shock treatment per se resulted in lower NE levels in the hippocampus. These data implicate the serotonergic and noradrenergic systems as possible mediators of the learned helplessness phenomenon, but do not support the view that this behavior is associated with impaired pituitary-gonadal function.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1984

Generation of antibody diversity in the immune response of BALB/c mice to influenza virus hemagglutinin.

We have examined the amino-terminal sequence of the kappa light chains of a set of monoclonal antibodies specific for one of the major antigenic determinants (Sb) on the influenza virus PR8[A/PR/8/34(H1N1)] hemagglutinin molecule. This set was believed to be structurally related from earlier serological analysis that typed these kappa chains as members of the variable (V) region V kappa 21 group [ Staudt , L. M. & Gerhard , W. (1983) J. Exp. Med. 157, 678-704]. Our sequence analysis confirms and extends this conclusion; all examples of this set belong to a subgroup of the V kappa 21 group, V kappa 21C . A special feature of this set of kappa light chains is that all examples were derived from the same mouse (designated H36 ). This sequence analysis along with the characterization of gene rearrangements at the kappa light chain loci of these hybridomas is consistent with the idea that certain members of this set are the progeny of one or two lymphocytes. Because of this potential clonal relationship, we can reach several conclusions about the diversity observed among these kappa light chains: (i) the diversity is due to somatic mutation, (ii) somatic mutations occur sequentially and accumulate in the first complementarity-determining region, and (iii) the extent of somatic variation in this sample is high, suggesting a somatic mutation rate of about 10(-3) per base pair per generation.

Amino Acid Sequence↗
PubMed1984

Activity-wheel stress: effects on brain monoamines and the pituitary-gonadal axis.

The study was designed to study the possible role of dopaminergic and serotonergic systems in pituitary gonadal function following activity stress. 3 groups of rats were caged individually. 1 group of rats (AW) was fed for 1 h each day and had free access to a running wheel. The 2nd group (FC) had no access to a running wheel and received exactly the same amount of food as animals of the AW group. The 3rd group (UC) had 24-hour access to food. AW rats showed a gradual increase in running activity which accompanied a gradual decrease in food consumption. AW rats were sacrificed, together with their matched FC counterpart and a UC control rat, on the day that their food consumption fell below 4 g/day. The brains were dissected into nine specific areas and subjected to analysis for dopamine (DA), 3,4-dihydroxyphenylacetic acid (DOPAC), serotonin (5-HT), and 5-hydroxyindoleacetic acid (5-HIAA) using high-performance liquid chromatography with electrochemical detection. Trunk blood was analyzed for serum levels of testosterone (T), luteinizing hormone (LH) and corticosterone (C), and weights of tests and epididymides were recorded. Both activity stress and restricted food intake resulted in a fall in serum levels of T and LH. Elevated levels were found for DOPAC in the hippocampus, hypothalamus, brainstem, and midbrain of activity-stressed rats. Levels of 5-HT and 5-HIAA were lower in the hypothalamus of these animals. Data analysis suggests a dopaminergic and serotonergic involvement in pituitary-gonadal function under activity-stress conditions.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1983

Ultrastructural features of the murine cutaneous microvasculature after exposure to polychlorinated biphenyl compounds (PCBs) and benzo-(a)-pyrene (BAP).

Exposure to polychlorinated biphenyl compounds (PCBs) has resulted in a variety of cutaneous effects in several species. When mice were exposed to PCBs through the diet and to benzo-(a)-pyrene (BAP) by topical application, hyperkeratinization occurred in the epidermis and hyperkeratinized cysts occasionally formed, but alterations were also observed in the dermis and in small cutaneous blood vessels, particularly capillaries and venules. The luminal borders of the endothelial cells often became irregularly ruffled, and pinocytotic vesicles increased in number and varied considerably in size. Subjacent to the endothelium and pericytes, the basal laminae were either replicated many times or extensively thickened. These effects were attributable to PCBs but not to BAP with the methods and dosages employed. Although endotheliocytosis has been reported in birds exposed to PCBs, vascular effects have not been previously described in mammals treated with these compounds.

Animals↗
PubMed1982

Phagedena: gangrenous and necrotic ulcerations of skin and subcutaneous tissue.

Phagedena is an old term for serious deep, necrotic and gangrenous skin ulcers. In the past these have been regarded as severe infections. A review of 31 cases revealed that except in cases of Streptococcus pyogenes or Clostridium welchii infection a bacterial of fungal infection was only one of several factors that led to the development of phagedenic ulcers. Initiating factors may be a bacterial infection, a debilitated state as a result of immunosuppressive therapy or of such conditions as alcoholism, severe diabetes, inflammatory bowel disease or severe arteriosclerosis, and various types of injury or trauma. Continuing factors include enzymatic mechanisms, the release of toxins from large areas of dead tissue and vascular disorders. In general, antibiotics are of limited value. systemic corticosteroid therapy may be useful in the subacute or chronic case. In acute, spreading, gangrenous phagedena with surrounding erythema, fever and systemic toxic effects, immediate excision of dead tissue may be lifesaving.

Gangrene↗
PubMed1981

Serum copper oxidase activity (coeruloplasmin) in chronic pancreatitis: inverse correlation with pancreatic exocrine function.

Serum copper oxidase activity (coeruloplasmin, ferroxidase, I, EC 1.16.3.1) and serum C-reactive protein (CRP) were estimated in 43 patients with chronic pancreatitis; total serum copper was also measured in 23 patients. Pancreatic exocrine function was assessed in all patients and compared with the respective copper oxidase activities. The following results emerged: (1) there was a strong positive linear relationship between total serum copper and serum copper oxidase activity; (2) in 34 patients CRP was undetectable Twenty-six patients were untreated and eight had received pancreatic extracts for variable periods of time. In the untreated patients there was an inverse correlation between serum copper oxidase activity and pancreatic exocrine function; (3) in the eight treated patients serum cooper oxidase activity was less than in untreated patients; (4) in three patients who were assessed before and six months after administration of pancreatic extracts serum copper oxidase activity showed a significant reduction with treatment; (5) nine patients with elevated CRP values also had raised serum copper oxidase activities but there was no correlation between these two serum constituents. The rise in serum copper which occurs in uncomplicated and untreated chronic pancreatitis does not represent an acute phase reaction. Our results provide further evidence that the pancreas assists in regulating copper metabolism in man.

Adult↗
PubMed1980

Pulmonary lamellar bodies in human amniotic fluid: their relationship to fetal age and the lecithin/sphingomyelin ratio.

We investigated the appearance of pulmonary lamellar bodies (LBs) in human amniotic fluid as a function of fetal age. We also studied their relationship to the lecithin/sphingomyelin (L/S) ratio and to the results of the rapid surfactant test (RST). LBs observed in amniotic fluid generally ranged in diameter from 1.5 to 2.0 mu and were seen as single structures or in clusters. When patients were grouped by gestational age, there was a significant difference (P less than 0.001) in the distribution of amniotic fluid LBs. No LBs were observed in amniotic fluid before 26 weeks' gestation, but 50% of specimens at 28 to 32 weeks' gestation and 85% of specimens at term had LBs. Patients with amniotic fluid LBs had higher L/S ratios and intermediate or mature RST values when compared to patients without LBs, but a statistically significant relationship between the presence of LBs and the L/S ratio or RST was not found. We conclude that qualitative examination of amniotic fluid LB content by conventional electron microscopy is unlikely to reflect fetal lung maturation in a precise manner. However, direct quantification of LBs may provide a more specific index of fetal lung maturity and the risk of respiratory distress syndrome.

Amniotic Fluid↗
PubMed1979

Malaria in Birmingham and a London teaching hospital.

During the past five years the incidence of imported malaria increased among patients seen in East Birmingham Hospital and in St Thomas's Hospital, London. Plasmodium vivax was the predominant species in Birmingham, and was almost always acquired by Asian immigrants visiting the Indian subcontinent. In St Thomas's P falciparum was most commonly imported, usually by African immigrants visiting Nigeria and Ghana. Two patients (one Irish, one Japanese) died of falciparum malaria after visiting tropical Africa. In both hospitals the immigrant patients had seldom taken prophylactic drugs, and the few who had, ceased to do so on arrival in the UK and sometimes before leaving the malarious country. Apparently immigrants who visit their homeland do not consult their general practitioners before travelling, are given inappropriate advice, or do not take appropriate advice when given. Since the incidence of imported falciparum malaria in the UK is rising, the following points should be considered: the infection may be lethal, particularly in patients lacking immunity; it can mimic other diseases, which may lead to delayed diagnosis; severe disease may be associated with few parasites on a blood film, and even if the result is negative further tests should be performed; clinicians and hospital pharmacists should be aware of the need to keep permanent stocks of parenteral chloroquine and quinine preparations.

Adolescent↗
PubMed1979

Polychlorinated biphenyl-induced morphologic changes in the gastric mucosa of the rhesus monkey.

The early morphologic events in polychlorinated biphenyl-induced lesions of the gastric mucosa of immature male rhesus monkeys (Macaca mulatta) were studied in serial biopsies taken during consumption of diets containing 3, 10, 30, and 100 mg. per kg. (p.p.m.) of Aroclor 1242. The severity of the lesions correlated directly with both the duration and the level of exposure. The first changes were seen after ingestion of 30 and 100 mg. per kg. for 2 weeks; changes were not seen until 10 weeks at 3 and 10 mg. per kg. The principal effect was an apparent arrest of the differentiation of generative cells of the isthmus and neck regions into parietal and zymogenic (chief) cells. Mature parietal and zymogenic cells were found only in the bases of the glands, where the oldest cells are normally found, and these showed signs of injury including dilation of the rough endoplasmic reticulum in zymogenic cells, irregularity of the mitochondria in parietal cells and irregular luminal membranes, and an increase in the number of large autophagic vesicles in both cell types.

Animals↗
PubMed1979

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History, 19th Century↗