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Biomedical subjects

C Hudson

Publications and source records attributed to C Hudson.

At least 19 recordsLinked to original sources

Assessment of physiologic statokinetic dissociation by automated perimetry.

The effects of age, stimulus size, meridian, and eccentricity on physiologic statokinetic dissociation were investigated in clinically normal subjects using the Humphrey field analyzer (HFA, model 640), an automated perimeter capable of both static and kinetic perimetry. The right eyes of 20 age-matched young and 20 age-matched elderly volunteers was examined along the 15 degrees and 195 degrees meridians with six Goldmann size I and five size III kinetic stimuli. These were chosen to produce a spread of discrete eccentricities. Kinetic sensitivity was determined seven times for each stimulus, and the mean stimulus locations were expressed in terms of their x and y coordinates. Static sensitivity for each stimulus size then was determined seven times at each of the corresponding locations using a custom threshold program. The area under each sensitivity gradient was determined using the trapezium rule. Group mean kinetic sensitivity was greater than group mean static sensitivity (P < 0.001), and this difference was largely independent of age, stimulus size, meridian, and eccentricity.

Adult

Childhood leukaemia and poliomyelitis in relation to military encampments in England and Wales in the period of national military service, 1950-63.

OBJECTIVE: To determine if any excess of childhood leukaemia was associated with the large and increasing numbers of national military servicemen in 1949 and 1950, particularly in rural districts. This would be a further test of the hypothesis that childhood leukaemia can originate in an infection, the transmission of which is facilitated by an increased number of unaccustomed contacts in the community. DESIGN: Rural and urban districts, aggregated by county, were ranked by proportion of servicemen, and five groups containing similar numbers of children were created. In addition, individual local authority districts were ranked and grouped in tenths. Mortality from childhood leukaemia 1950-3 was examined in these groups. Data on infectious diseases were also examined, as well as data on leukaemia in later periods. SETTING: England and Wales. SUBJECTS: Children aged under 15 years. RESULTS: In 1950-3 but not subsequently a significant excess of leukaemia in children under 15 was found in the fifth of county groupings with the highest proportions of servicemen. This was due mainly to a significant excess in children under 2 years (and especially in those under 1 year) in rural districts. It was confirmed among the tenth of local authority districts with the highest proportion of servicemen. These rural areas showed significantly more notifications of, and deaths from, poliomyelitis among children than the rural average. CONCLUSIONS: The findings support the infection hypothesis. That the excess of leukaemia was greatest in children under 1 year suggests transmission of infection among adults and thence to the fetus. The pattern of spread of poliomyelitis may also have been influenced by the presence of large numbers of servicemen.

England

Evidence from population mixing in British New Towns 1946-85 of an infective basis for childhood leukaemia.

Mortality from leukaemia under age 25 was studied in British New Towns to test the hypothesis that leukaemia represents a rare response to a much commoner (but unrecognised) infection, the transmission of which is facilitated when large numbers of people come together. The density of children was higher in the rural, but lower in the overspill, New Towns than in the areas from which their incomers originated. Residents of the rural New Towns had greater diversity of origin than those of the overspill towns of London and Glasgow. These two factors would encourage a greater rise in the postulated underlying infection in the rural towns, and in these a significant excess of leukaemia at ages 0-4 was found in 1946-65. In both sets of towns there was a significant deficit in other age groups consistent with immunising effects of the relevant infection. There are parallels with feline leukaemia virus infection, in which contrasting leukaemogenic and immunising effects occur in different social settings owing mainly to differences in intensity of viral exposure.

Adolescent

Systemic administration of MK-801 protects against N-methyl-D-aspartate- and quisqualate-mediated neurotoxicity in perinatal rats.

MK-801, a non-competitive antagonist of N-methyl-D-aspartate-type glutamate receptors, was tested for its ability to antagonize excitotoxic actions of N-methyl-D-aspartate or quisqualic acid injected into the brains of seven-day-old rats. Stereotaxic injection of N-methyl-D-aspartate (25 nmol/0.5 microliters) or quisqualic acid (100 nmol/1.0 microliter) into the corpus striatum under ether anesthesia consistently produced severe unilateral neuronal necrosis in the basal ganglia, dorsal hippocampus and overlying neocortex. The distribution of the damage corresponded to the topography of glutamate receptors in the vulnerable regions demonstrated by previous autoradiographic studies. N-Methyl-D-aspartate produced severe, confluent neuronal destruction while quisqualic acid typically caused more selective neuronal necrosis. Intraperitoneal administration of MK-801 (0.1-1.0 mg/kg) 30 min before N-methyl-D-aspartate injection had a prominent dose-dependent neuroprotective effects as assessed morphometrically by comparison of bilateral striatal, hippocampal and cerebral hemisphere cross-sectional areas five days later. A 1 mg/kg dose of MK-801 given as pre-treatment completely protected the infant brain. The same dose of MK-801 was also completely protective when administered 30 or 40 min after N-methyl-D-aspartate and afforded partial protection when given 2 h later. MK-801 pre-treatment also prevented the electrically confirmed behavioral seizures induced by N-methyl-D-aspartate. The drug significantly reduced striatal but not hippocampal or neocortical injury when given as two doses (1 mg/kg) 30 min prior to and immediately following quisqualic acid injection. The data indicate that systemic administration of MK-801 can prevent N-methyl-D-aspartate-induced neuronal injury in perinatal rat brain even when administered after the initial insult. MK-801 also partially antagonized quisqualic acid-mediated neurotoxicity, suggesting that quisqualic acid-induced toxicity is, in part, mediated through N-methyl-D-aspartate receptor activation. The sensitivity of the developing brain to the toxicity of N-methyl-D-aspartate provides a sensitive and reproducible in vivo model for exploring these issues and for screening prospective neuroprotective drugs that act at the N-methyl-D-aspartate receptor-channel complex.

Animals

Fatal post-splenectomy sepsis in a Papua New Guinean highlander.

A fatal case of overwhelming post-splenectomy sepsis (OPSS) occurring 5 years after splenectomy for trauma in a Papua New Guinean highlander is presented. The diagnosis of pneumococcal infection was made from a peripheral blood smear. The finding of OPSS in Papua New Guinea is cited as additional evidence in favour of a policy of conservative management, where possible, of ruptured spleen.

Adult

Abnormal thyroid hormone and thyrotropin levels in homozygous sickle cell disease.

Male patients with SS disease had significantly lower T3 and higher TSH levels than a comparison group. Stimulation with TRH in 10 male sibling pairs showed highly significant increases in T3 and TSH in both patients and sibling controls although the increase in TSH was significantly greater in SS disease. The interpretation of these findings is unclear although the thyroid indices indicate an abnormal pituitary-thyroid axis most consistent with a modest primary thyroid failure.

Adolescent

Anomalous motoric lateralization and schizophrenia: clinical implications.

Sixty-five schizophrenic subjects (46 men and 19 women) were tested for motor preference and compared to age and sex-matched controls. There were significantly more nondextrals among the schizophrenic women. Both male and female nondextral schizophrenics were hospitalized more frequently and for longer periods than dextral schizophrenics.

Adolescent

Effects of postnatal hypoxia-ischemia on cholinergic neurons in the developing rat forebrain: choline acetyltransferase immunocytochemistry.

We studied the effect of early postnatal hypoxia-ischemia on cholinergic neurons in the developing rat forebrain using immunohistochemistry for choline acetyltransferase (ChAT). In 7-day-old rat pups, hypoxia-ischemia was induced in one cerebral hemisphere by combining unilateral carotid ligation with exposure to 8% oxygen for 2.5 h. This procedure caused brain injury in the hemisphere ipsilateral to ligation, most prominent in the corpus striatum, hippocampus and overlying cortex. In animals sacrificed 2-3 weeks after the insult, at approximately 3 weeks of age, the density of cholinergic cell bodies was slightly higher in the lesioned rostral caudate-putamen than the opposite side (+12%, P less than 0.05). In the more caudal portion of caudate-putamen, this effect was greater. In contrast, the size of the cholinergic perikarya in the injured striatum was significantly reduced. Cholinergic neurons in the septum (Ch1, Ch2), globus pallidus and nucleus basalis (Ch4) were relatively unaffected. Considered together with previously reported neurochemical data, these observations suggest that the immature cholinergic neurons are less vulnerable to death from hypoxia-ischemia than other components of the striatum. However, differentiation of surviving cholinergic perikarya and possibly their axonodendritic processes may be disrupted by the early insult.

Age Factors

Evidence for transient perinatal glutamatergic innervation of globus pallidus.

There is no known glutamatergic innervation of globus pallidus (GP) in adult mammals, but we report that during postnatal development of the GP there are large, transient increases in both presynaptic high-affinity glutamate uptake and postsynaptic Na+-independent glutamate receptor binding. These glutamatergic markers increase rapidly in rat GP after birth and then decrease to adult levels over a period of weeks. A similar developmental pattern of pallidal glutamate binding was found in human brains. In contrast, binding in rat caudate-putamen (CPu) increases after birth, reaches a peak, and remains constant into adulthood. The results suggest that a glutamatergic pathway transiently innervates the globus pallidus during the perinatal period. Because glutamate is an excitotoxin, this pathway may account, in part, for the basal ganglia damage seen in some forms of cerebral palsy after perinatal hypoxia/ischemia.

Adult

Children's adjustment to the hospital: a rural/urban comparison.

This paper presents the findings of an investigation to determine whether or not there is a difference in the degree of psychological upset of rural and urban children during hospitalization. The subjects in the study were 70 children between the ages of 4 and 17 years who participated in the Child Life Program during hospitalization at Children's Hospital in Birmingham, Alabama. The anxiety levels of the children were evaluated by using three instruments: a 13-item, self-report test of fears; a 64-item observation checklist of negative behaviors; and a 4-item anxiety rating scale. The results revealed that on specific measures rural children exhibited a statistically significantly greater degree of psychological upset during hospitalization than urban children. Implications of these results in determining procedures to reduce anxiety of children during hospitalization are briefly considered.

Adaptation, Psychological

A retrospective study of Creutzfeldt-Jakob disease in England and Wales 1970-1979. II: Epidemiology.

A comprehensive search yielded 121 confirmed cases of Creutzfeldt-Jakob disease who died in England and Wales in the decade 1970-1979, 31 probable cases and 10 possible cases. Descriptive epidemiological data are presented. The average annual incidence was 0.3 cases/million. An unexpected female excess was found. There was no evidence of space-time clustering of cases and no associations with occupation or past medical treatment were apparent. There was statistically significant variation in incidence rates in different parts of the country but no relationship was discovered between incidence and population density.

Adult

A comparison of the performance of three multiple choice question papers in obstetrics and gynaecology over a period of three years administered at five London medical schools.

Four, and later five, of the medical schools in the one multiple choice question (MCQ) paper in Obstertrics and Gynaecology to their students at the end of the Obstetrics and Gynaecology courses. The paper was amended twice after intervals of approximately 12 months. The results showed differences in performance between the five schools on questions and alternatives within questions, which were common to all editions of the paper (the "short" paper). These differences were also shown in the first two editions of the full paper (the "long" paper), but were not apparent in the third. There was a significant improvement in performance from the first to the second paper edition of the long by approximately 11%, but this was reversed from the second to the third edition, where there was a significant decrease in performance by approximately 4%. We cannot here exclude the possibility that this decrease in the third edition has resulted from sample bias. The rank order of the schools may result from differences in methods of teaching. It seems that such relative performance between London medical schools in contributed to by the differences in course legnth and by the occurence of mid-course test. It appears also that student performance in any of the schools has not been uniform over the period of the study, there being a peak during the period when the second edition of the paper was used. Variations in student selection occuring between schools may effect some of these differences. There was also a marked difference in students' performance between Obstetrics and Gynaecology. The short papers appeared easier than the full papers. Whilst this may due to the greater clarity of phrasing for the questions of the short paper, we also believe the subject matter of the short paper may be more relevant. A distinct effect could also be shown, over the period, due to improvements in the wording of the questions. It is possible that students perform better at Obstetrics than at Gynaecology.

Curriculum

Arthritis in the prehistoric Southeastern United States: biological and cultural variables.

Recent research shows that a bacterial life form, Erysipelothrix insidiosa, can produce rheumatoid arthritis in deer, swine, and dogs, and that a number of animals, including man, birds, and fish, may be infected by the organism. Examination of the archaeological record suggests that both cultural and biological variables may be interrelated in the maintenance of some forms of arthritis over long periods of time in geographically disparate populations. Re-examination of Cherokee folk beliefs concerning arthritis suggests that they had some recognition of this connection, and it also suggests that they had some recognition of this connection, and it also suggests that the term "magical" may relate more to the world view of the observer than to any actual inability of preliterate peoples to draw causal relations on the basis of their own intimate knowledge of their environments.

Alabama