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Biomedical subjects

J M Smith

Publications and source records attributed to J M Smith.

At least 19 recordsLinked to original sources
PubMed1979

Game theory and the evolution of behaviour.

How far can game theory account for the evolution of contest behaviour in animals? The first qualitative prediction of the theory was that symmetric contests in which escalation is expensive should lead to mixed strategies. As yet it is hard to say how far this is borne out, because of the difficulty of distinguishing a 'mixed evolutionarily stable strategy' maintained by frequency-dependent selection from a 'pure conditional strategy'; the distinction is discussed in relation to several field studies. The second prediction was that if a contest is asymmetric (e.g. in ownership) then the asymmetry will be used as a conventional cue to settle it. This prediction has been well supported by observation. A third important issue is whether or not information about intentions is exchanged during contests. The significance of 'assessment' strategies is discussed.

Aggression↗
PubMed1979

Asthma.

Explore the source record for details and available documents.

Asthma↗
PubMed1979

An assessment of tardive dyskinesia in schizophrenic outpatients.

An examination of tardive dyskinesia in 213 schizophrenic outpatients using the Abnormal Involuntary Movement Scale (AIMS) indicates that increasing age is significantly associated with the presence of this disorder while sex is not. Both sexes showed significant linear increases with increasing age. Although males did not evidence the statistically significant curvilinear trend previously reported in an inpatient study using the same methodology, they displayed an attenuated effect at the older age levels. A comparison of prevalence values between the outpatient sample and the inpatient sample previously studied indicated no greater prevalence in the outpatients. However, an examination of differences in AIMS total scores between these samples suggested the presence of many more marginal and mild movements in the outpatients. Reasons for the differences between the inpatient and outpatient studies are discussed.

Adult↗
PubMed1979

Synaptic fine structure and the termination of corticospinal fibers in the lateral basal region of the cat spinal cord.

The lateral basal region (LBR) of the spinal cord gray matter (Rexed's laminae IV-VII) by physiologic and anatomic criteria is the major terminal zone for the corticospinal (CS) tract in the cat. The neurons in this area are medium-sized with abundant spines on their dendrites. Axon terminals on the dendrites and somata of these neurons form synapses easily classified as asymmetric with spheroid vesicles and symmetric with flattened vesicles. There are rare exceptions to this. In a systematic count of terminals, 82% have spheroid and 18% flattened vesicles. The majority of all terminals are on dendrites (84.9%) and a minority on somata (14.1%). Less than 1% are axoaxonic. Degeneration of the corticospinal tract was produced by transecting one hemisphere of our experimental cats. Its termination in the lower cervical cord was studied for 17 hours to 7 days after surgery. Vesicle depletion and clumping and dense polymembranous inclusions were the most common forms of degeneration. Filamentous proliferation in the terminals was also prominent; dark degeneration, however, was infrequent. The percent of degenerating CS terminals in the LBR was the following: 17 hours - 2.2%, 36 hours - 4.19%, 2 days - 10.3%, 3 days - 8.4%, 4 days - 6.9%, 7 days - 10.25%; 84.8% of degenerating CS terminals were axodendritic and 15.2% axosomatic.

Animals↗
PubMed1979

Mutations affecting the formation of acetohydroxy acid synthase II in Escherichia coli K-12.

Genetic mapping experiments have established that two recently isolated valine-resistant mutants of the K-12 strain of Escherichia coli have lesions lying between ilvE and rbs. These lesions allowed expression of the ilvG gene, specifying the valine-insensitive acetohydroxy acid synthase (synthase II) and an increased expression of the ilvEDA operon. In this respect, they resembled an earlier described ilvO lesion that was reported to lie between ilvA and ilvC. All three lesions were cis-dominant in cis-trans tests. Reexamination of the earlier studied ilvO lesion revealed that it, too, lies between ilvE and rbs. Valine-sensitive derivatives with lesions presumed to be in ilvG were selected from each of the valine-resistant strains. In two of the valine-resistant strains, the ilvG mutations were on the rbs side of ilvO, indicating a gene order rbs-ilvG-ilvO-ilvE-ilvD-ilvA-ilvC. In one of the recently isolated valine-resistant stocks, however, the apparent ilvG mutation was found to be between ilvE and the aline resistance marker. This finding suggests that either ilvO and ilvG mutations are interspersed or there is another locus, ilvR, that behaves phenotypically like ilvO and which lies between ilvG and rbs.

Acetolactate Synthase↗
PubMed1979

A technique for reducing the beam width of the Doppler ultrasound probe with potential application for accurate location of small superficial arteries.

A simple technique for reducing the beam width of the Doppler ultrasound probe is described. This is accomplished by attaching a plexiglas prism to the transducer surface of the conventional probe. It reduces the beam width by a ratio of 2.8:1. This improves the precision with which the probe is able to locate small superficial arteries.

Arteries↗
PubMed1979

Primary nonfunctioning carcinoma of adrenal cortex.

Two cases of nonfunctioning adrenocortical carcinomas are presented. The clinical features, operative findings, and histopathologic appearances are discussed. It is believed that these tumors are difficult to diagnose because of their vague presentation. Intravenous urography with nephrotomography is the most valuable method of detecting these tumors, and surgery remains the best treatment.

Adrenal Cortex↗
PubMed1979

Oral and dental discomfort--a necessary feature of old age?

A socio-dental study was conducted among an elderly population living at home. The dental status of the sample was generally poor; 74% were edentulous and only 10% of the full denture wearers had appliances which were clinically satisfactory. Nearly 60% of the subjects had pathological lesions of the oral mucosa, mainly associated with the wearing of dentures. Many of the subjects were handicapped either socially or functionally by their oral conditions; 40% had oral pain, 30% had difficulty chewing and 20% were embarrassed by their dentures dropping during social contact. Although 78% were assessed as needing treatment only 19% had tried to obtain it. Various reasons were mentioned for not obtaining dental treatment, including immobility, fear and prohibitive cost. Reasons for the present state of the dental health of the elderly are discussed.

Aged↗
PubMed1979

Postoperative analgesia.

Postoperative analgesia both by drugs and regional techniques is reviewed. In the United Kingdom in the last 25 years or more there has been little advance on either front. Some marginal improvement in regard to drugs might be brought about by better education of both doctors and nurses and better patient contact. Extradural analgesia and intercostal block do not offer a complete solution, though a judicious increase in the use certainly of the former might be beneficial. The problem awaits a radical new approach.

Administration, Oral↗
PubMed1979

IgE and IgG4 subclass in atopic families.

Raised levels of IgG4 were present in twelve (35%) of thirty-four asthmatic children and raised levels of IgE in twenty-three (68%). Eighteen of 104 first degree relatives also had raised levels of IgG4, thirteen had no history of atopic disease and nine failed to give positive skin reactions to Dermatophagoides pteronyssinus or to mixed grass pollens. Fifteen relatives had raised IgE, five without symptoms. No relationship was noted between either raised levels of IgE or IgG4 and infant feeding. Although these immunoglobulin patterns were not consistently associated with symptoms they did tend to be associated in atopic families and it is suggested that the same polygenic factors may govern the IgE and IgG4 levels.

Adolescent↗
PubMed1979

Atopic disease and month of birth.

Analysis of the month of birth of 1715 children with asthma shows clear evidence of a higher proportion of the group having been born between May and October (54.8%) than would be expected by comparison with the population of England and Wales (50.2%). Inspection of the distribution of month of patients with hay fever and for patients with positive skin reactions to mixed grass pollen does not account for this seasonal variation but children with positive skin reactions to Dermatophagoides pteronyssinus show a high proportion (56.2%) born in the period May to October. Although the reasons for the variation of pattern of month of birth in asthmatic children are uncertain, further study of sensitization in early life might clarify them.

Adolescent↗
PubMed1979

How dental conditions handicap the elderly.

A sociodental investigation was carried out among 254 elderly people living at home in Nottinghamshire. The aim of the inquiry was to ascertain whether this group of people were handicapped by their dental conditions. The dental status of the sample was generally poor. 74% were edentulous and the condition of the full dentures worn by many of the subjects was unsatisfactory. A high proportion (59%) of the subjects had lesions of the oral mucosa. Many members of the sample were orally handicapped, either functionally or socially. 32% complained of oral pain and 30% claimed to have difficulty chewing. Also, subjects were embarrassed by the appearance of their teeth and by their dentures dropping during social contact. The perception of handicap, however, was not strongly related to dental status.

Activities of Daily Living↗
PubMed1979

Effect of parathyroid hormone on plasma renin activity and sodium excretion.

The interaction between parathyroid hormone (PTH) and the renin-angiotensin system was evaluated in pentobarbital-anesthetized dogs. An intravenous infusion of bovine PTH (1-34) for 1 h was accompanied by a 57% increase (13.7-21.6 ng/ml per h) in plasma renin activity (PRA) which returned toward control levels during the recovery period. Sodium and phosphate excretion also increased. Second the endogenous secretion of PTH was stimulated by infusion of citrate into the blood supply of the thyroparathyroid glands to determine if the stimulatory effect on renin occurred with endogenous secretion of PTH. Phosphate excretion increased, which confirmed PTH secretion. There was a significant rise (57%) in both PRA (6.1-9.8 ng/ml per h) and sodium excretion, the magnitude of the sodium response modulating the increase in PRA. Blood pressure remained constant. In a third set of experiments, thyrocalcitonin was infused intravenously and had no effect on PRA. These data indicate that both exogenous and endogenous PTH can elevate PRA and increase sodium excretion. The sodium effect is probably the result of inhibition of proximal sodium reabsorption by PTH. The mechanism by which PTH elevates PRA is not known.

Animals↗