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Biomedical subjects

A Williams

Publications and source records attributed to A Williams.

At least 595 records · Page 33Linked to original sources
PubMed1983

Hepatitis B virus vaccine.

Hepatitis B is a major public health problem. Complications of the disease can include a carrier state, chronic active hepatitis, cirrhosis and hepatocellular carcinoma. The development of hepatitis B virus vaccine has made active immunization against HBV possible. Although studies are still in progress, the vaccine appears quite safe and remarkably free of side effects. Vaccination is recommended for individuals who are at risk for exposure to infectious blood or body fluids from hepatitis B patients.

Adult↗
PubMed1983

Fatal injuries to bicyclists: the experience of Dade County, Florida.

Among 173 fatally injured bicyclists, the head or neck was the region most seriously injured in 86%. The frequency of injury to the head and neck region and the frequency of nonsurvivable (AIS 6) injury were highest among the cases aged 16 years or less. Vertebral fractures occurred most often in the highest cervical vertebra (C1) and progressively less often in lower vertebrae. The relationship between vertebral position and fracture likelihood is approximately log linear. Bicyclists with a relatively long time from injury to death tended to be older persons with survivable injuries. They often died from complications (pneumonia, pulmonary embolus) rather than directly from their injuries.

Accidents, Traffic↗
PubMed1982

Spinal cord swelling and candidiasis. A case report.

Fusiform swelling of the spinal cord was noted myelographically in a patient with Hodgkin's disease. Autopsy revealed that the swelling was caused by Candida infection of the spinal cord. It is suggested that fungal infection be included in the differential diagnosis of spinal cord swelling in the immunosuppressed cancer patient.

Adult↗
PubMed1982

Evidence for host resistance in 1,3 bis(2-chloroethyl)-1-nitrosourea treatment induced in syngeneic LSA lymphoma.

The anticancer agent 1,3 Bis(2-chloroethyl)-1-Nitrosourea (BCNU) cures the advanced syngeneic LSA lymphoma of C57BL mice with high efficiency. The cured animals resist further tumor challenge by large numbers of viable syngeneic tumor cells. Growth assays of spleen proliferation of the intravenously inoculated tumor revealed a progressive-regressive pattern of spleen growth after LSA-tumor injection. Lymphoma colony forming units (LCFU) in the spleen initially increased then regressed. In vitro assays of serum showed a lack of cytotoxic activity in mice cured by BCNU. Added spleen, thymus, or bone-marrow cells were similarly ineffective. Spleen and bone-marrow cells from immune mice passively transferred to normal mice showed weak cytotoxic activity against the LSA tumor. BCNU-cured mouse cells were more effective in protection than those cured with Chlorozotocin (CLZ).

Animals↗
PubMed1982

Clinical experience with ORG NC45 (norcuron) as the sole muscle relaxant.

The neuromuscular effects of ORG NC45, used as the sole muscle relaxant, were compared with a succinylcholine-pancuronium sequence in patients during nitrous oxide-fentanyl anaesthesia. The subjects were divided into four groups with ten in each group. After induction of anaesthesia they received either succinylcholine, 1 mg . kg-1 or ORG NC45 in doses of 50, 70 or 90 micrograms . kg-1 and tracheal intubation was done 90 seconds later. Neuromuscular transmission was monitored using train-of-four stimulation. Succinylcholine produced 100 per cent block with uniformly excellent intubating conditions whereas the three doses of ORG NC45 were associated with blocks of 7.5, 18.7 and 30.7 per cent and acceptable conditions in only 30 per cent of subjects. Muscle relaxation was maintained in the NC45 groups with increments of 10 micrograms . kg-1 and in the succinylcholine group with pancuronium, initially as a bolus of 40 micrograms . kg-1, followed by increments of 5 mg . kg-1. All increments were given at 10 per cent recovery of twitch height. The overall requirement to maintain 90 per cent block with pancuronium was 1.1 microgram/kg-1 . min-1 compared with 1.28 microgram . kg-1 . min-1 with ORG NC45. No cumulative effects were seen with either drug during the first hour of neuromuscular blockade. At the end of the operation the neuromuscular block was antagonized with atropine 18 micrograms . kg-1, and neostigmine 36 micrograms . kg-1 and recovery was significantly more rapid with NC45 than pancuronium. We conclude that the lack of cumulation, easy reversibility and lack of cardiovascular effects suggest that NC45 has advantages over currently available non-depolarizing muscle relaxants but that its onset of action is too slow for rapid intubation.

Adult↗
PubMed1982

The relationship between two visual communication systems: reading and lipreading.

To explore the relationship between reading and lipreading and to determine whether readers and lipreaders use similar strategies to comprehend verbal messages, 60 female junior and sophomore high school students--30 good and 30 poor readers--were given a filmed lipreading test, a test to measure eye-voice span, a test of cloze ability, and a test of their ability to comprehend printed material presented one word at a time in the absence of an opportunity to regress or scan ahead. The results of this study indicated that (a) there is a significant relationship between reading and lipreading ability; (b) although good readers may be either good or poor lipreaders, poor readers are more likely to be poor than good lipreaders; (c) there are similarities in the strategies used by readers and lipreaders in their approach to comprehending spoken and written material; (d) word-by-word reading of continuous prose appears to be a salient characteristic of both poor reading and poor lipreading ability; and (c) good readers and lipreaders do not engage in word-by-word reading but rather use a combination of visual and linguistic cues to interpret written and spoken messages.

Adolescent↗
PubMed1982

Cellular proliferation and susceptibility to iron toxicity in iron loaded cell cultures.

Chang cells from human liver, grown in a medium supplemented with 161 mumol/l ferric nitrilotriacetate become iron loaded with an increase in their ferritin content and total iron content. Their viability is not impaired and they survive indefinitely in this state when subcultured at regular intervals. When the cells are grown in a confluent culture their mitotic index is reduced from 12% to less than 1%. In this state they survive normally in unsupplemented medium but when iron is added at 161 mumol/l concentration the cells die within 6 weeks. The toxic lesion appears to be induced within three weeks and is irreversible unless the cells are transferred to an iron-poor medium. Cultural conditions, particularly proliferative rate, appear to be important in determining susceptibility of the cells to iron toxicity. Cell age, hypopoxia and lysosomal enzyme have been assessed as factors that may affect susceptibility.

Cell Division↗
PubMed1982

Pyridoxal complexes as potential chelating agents for oral therapy in transfusional iron overload.

Iron chelation therapy for patients maintained on a regular transfusion regime is at present best carried out by means of daily infusions of desferrioxamine (Hussain et al 1977; Pippard et al 1978) but this is onerous for the patient and has social and economic disadvantages. Many recent attempts to provide more effective drugs for iron chelation have been summarized by Jacobs (1979) and increasing attention is now being paid to the possibility of oral iron chelation therapy. Hoy et al (1979) showed that when isonicotinic acid hydrazide (INH) and pyridoxal are mixed in equimolar amounts a hydrazone is formed which chelates iron, and oral administration of this compound to rats results in an eightfold increase in faecal iron excretion. It is effective on repeated administration (Cikrt et al 1980), the main route of iron excretion being through the bile. Long term studies in the rat have not been successful in reducing the iron load of test animals and this appears to be related both to their high dietary iron content and instability of the hydrazone. Its effective shelf life at room temperature is no longer than one month and this is a considerable disadvantage from a therapeutic point of view. Pyridoxal is known to form a Schiff base with many amino acids and its reactivity has led us to examine complexes of pyridoxal with a number of substances in an attempt to find an alternative iron chelator of greater stability than the INH complex and of comparable effectiveness on oral administration. The screening procedures used were the effects on Chang cell iron metabolism (White et al 1976) and on iron excretion in the rat (Hoy et al 1979).

Animals↗
PubMed1982

Liver disease in India.

One hundred and twenty-five children with chronic liver disease were seen in Pune in 13 months. Fifty-nine of them, aged 8-39 months, had Indian childhood cirrhosis histologically diagnosed. Their characteristics included an insidious onset of symptoms, a geographical clustering of cases in rural areas north-east of Pune, a high rate of parental consanguinity and affected siblings, and a very high hepatic copper concentration (790-6654 micrograms/g dry weight). Only 8 survived for 6 months, adverse prognostic features being jaundice, ascites, enlargement of the gall bladder, and severe anaemia at presentation. Clinical differentiation from other liver disorders in the same age group was clear in advanced cases but unreliable in earlier cases. Four asymptomatic siblings with hepatomegaly had a benign course. The need for non-invasive methods to diagnose early cases in the community is demonstrated. The other major diagnostic categories were: unresolved hepatitis (12); chronic active hepatitis (7); cryptogenic cirrhosis (6); neonatal hepatitis and biliary atresia (8).

Adolescent↗
PubMed1981

Hydrogenosomes in the rumen protozoon Dasytricha ruminantium Schuberg.

This paper reports for the first time the presence in the anaerobic rumen ciliate Dasytricha ruminantium (Schuberg) of microbody-like organelles, about 0.5 micrometer diameter, with a granular matrix and an equilibrium density of approx. 1.18 g/ml. These organelles can be isolated in a fraction sedimented at 10(5) g-min that contains 67% of the total pyruvate synthase (EC 1.2.7.1), 66% of the hydrogenase (EC 1.18.3.1) and 20% of the lactate dehydrogenase (EC 1.1.1.27). Thus in several respects this fraction is enzymically similar to those containing hydrogenosomes in some other parasitic anaerobic protozoa (the trichomonads). However, in contrast with the hydrogenosomes of trichomonads, the oxygen-tolerant enzyme malate dehydrogenase (decarboxylating) (EC 1.1.1.40) is not particulate, but occurs only in the cytosol. These results enable the proposal of a scheme for the pathway of product formation (acetate, lactate, CO2 and H2) from carbohydrates.

Animals↗
PubMed1981

Pulmonary mast cells in cattle and ilamas at high altitude.

The density of mast cells in various anatomical locations within the lung were measured in a peruvian Andean llama, a Peruvian Andean cow and a sea-level-cow. These densities were determined separately around pulmonary arteries, pulmonary veins, pulmonary arterioles and venules, in the alveolar septa, and around bronchi. The total mast cell density did not differ significantly between the three animals and there were more periarteriolar and perivenular mast cells in the llama than in either of the two cows. These data do not support the hypothesis that the perivascular mast cell is responsible for initiating the vasopressor response to hypoxia. In fact it can be argued that they actually inhibit this response since a high mast cell density was found in the llama, and animal which does not develop pulmonary hypertension at high altitude.

Altitude↗
PubMed1981

Consumer participation and influence in a Health Systems Agency.

Consumer participation and influence were studied in one Health Systems Agency in the southeastern United States over a 20-month period (July 1976--February 1978). Consumer board members were found to be significantly less influential in agency decision making than were provider board members. This difference in influence existed even though virtually no difference existed between consumers' and providers' levels of participation. Consumer board members, while representing minority and nonminority, and both rural and nonrural groups, tended nevertheless also to be middle-class, middle-income individuals. Low-income and working-class groups were underrepresented on the board of the Health Systems Agency. Furthermore, consumer representatives tended to be satisfied with and have access to health care.

Adolescent↗
PubMed1981

Effect of precursors of the 1, 2, and 3 series prostaglandins on renin release and renal blood flow in the dog.

The precursors of the monoene, diene, and triene series of prostaglandins, eicosatrienoic acid, arachidonic acid, and eicosapentaenoic acid, respectively, were infused at 3 X 10-6, 10-5, and 3 x 10-5 g/kg/min directly into the renal artery of non-filtering, denervated kidneys of conscious propranolol-treated dogs. Renal blood flow was measured with an electromagnetic flow probe around the renal artery and renal renin secretion rate from blood samples taken from catheters in the aorta and renal vein. The highest dose of arachidonic acid increased renal blood flow by 54 +/- 19% and increased renin secretion rate seven-fold. Eicosatrienoic acid produced a smaller increase in renal blood flow but did not significantly increase renin secretion rate. Eicosapentaenoic did not change either blood flow or renin secretion rate. We conclude that compared with arachidonic acid the precursors of the 1 and 3 series of prostaglandins are not significantly involved in the regulation of renal blood flow or renin secretion.

8,11,14-Eicosatrienoic Acid↗
PubMed1981

Release of alpha-melanocyte stimulating hormone into rat and human cerebrospinal fluid in vivo and from rat hypothalamus slices in vitro.

The release of alpha-melanocyte stimulating hormone (alpha-MSH) from central nervous system neurons was investigated and demonstrated in vivo and in vitro. alpha-MSH immunoreactivity in rat and human cerebrospinal fluid (CSF) is comprised of deacetylated alpha-MSH, alpha-MSH and the methionine sulfoxide forms of these peptides. The sulfoxides are formed artifactually upon extraction. alpha-MSH in rat CSF is unaffected by hypophysectomy but is markedly increased by electrical stimulation of the mesencephalic central gray. These data indicate that CSF alpha-MSH is primarily of neuronal origin, alpha-MSH is also released in a calcium dependent manner from hypothalamic slices in vitro. The fact that the release of alpha-MSH is stimulated by veratridine and inhibited by tetrodotoxin demonstrates the necessity for neuronal sodium influx for alpha-MSH release. The presence of an alpha-MSH neurosecretory process supports a neurotropic role for this peptide in the central nervous system.

Animals↗