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Biomedical subjects

H Williams

Publications and source records attributed to H Williams.

At least 217 records · Page 12Linked to original sources
PubMed1985

Auditory responses in avian vocal motor neurons: a motor theory for song perception in birds.

The hypoglossal motor neurons that innervate the vocal organ (syrinx) of the male zebra finch show a selective, long-latency (50-millisecond) response to sound. This response is eliminated by lesions to forebrain song-control nuclei. Different song syllables elicit a response from different syringeal motor neurons. Conspecific vocalizations may therefore be perceived as members of a set of vocal gestures and thus distinct from other environmental sounds. This hypothesis is an avian parallel to the motor theory of speech perception in humans.

Animals↗
PubMed1985

Abortion due to infection with Chlamydia psittaci in a sheep farmer's wife.

A farmer's wife who had helped with lambing aborted spontaneously in March after a short febrile illness in the 28th week of her pregnancy. She developed disseminated intravascular coagulation post partum with acute renal failure and pulmonary oedema. Recovery was complete after two weeks of hospital care. A strain of Chlamydia psittaci, probably of ovine origin, was isolated from the placenta and fetus. The patient's serum showed rising titres of antibody against chlamydia group antigen; the placental and fetal isolates; and a known ovine abortion, but not a known avian, strain of C psittaci. IgG against both ovine abortion and enteric strains of C psittaci was detected, but IgM against only an abortion strain was detected. Histological examination showed pronounced intervillus placentitis with chlamydial inclusions in the trophoblast but no evidence of fetal infection or amnionitis. Laboratory evidence of chlamydial infection was found in an aborting ewe on the farm in January and in remaining sheep and lambs in July. Doctors should recognise the possible risk to pregnant women in rural areas where chlamydial infections in farm animals are widespread.

Abortion, Spontaneous↗
PubMed1985

Sexual dimorphism of auditory activity in the zebra finch song system.

While the tracheosyringeal motor neurons of anesthetized male zebra finches fire in response to acoustic stimuli, the same motor neurons in females show no such response. Females masculinized by estradiol implants on Days 1 or 2 after hatching may develop auditory responses in their tracheosyringeal motor neurons; the presence of the response is directly related to the degree of masculinization of the estradiol-treated females' telencephalic song centers. In male zebra finches, neurons in HVc (Hyperstriatum Ventrale pars caudalis) respond to sound, and the HVc is necessary for the tracheosyringeal auditory response. Multiunit auditory activity was demonstrated in the HVc of female zebra finches. A single 20-microA pulse delivered to the male HVc elicits a large volley in the tracheosyringeal nerve; microstimulating the female HVc does not evoke a response in the motor nerve. This failure of both auditory and HVc stimulation to elicit a response in the female tracheosyringeal nerve is attributed to the lack of a functional HVc-nucleus Robustus Archistriatalis projection in females. If, as has been suggested, the tracheosyringeal auditory response may be important for the processing of song, female zebra finches might not process song in the same manner as do males.

Animals↗
PubMed1985

Epidermolytic variant of hereditary palmoplantar keratoderma.

The seventh family with autosomal dominant epidermolytic palmoplantar keratoderma is reported. The lesions are clinically indistinguishable from Unna-Thost disease but resemble epidermolytic hyperkeratosis (bullous ichthyosiform erythroderma) histopathologically. A skin biopsy is essential for making the correct diagnosis. One of our patients was treated with isotretinoin for 13 weeks without significant improvement.

Adult↗
PubMed1985

Depression in mothers in a multi-ethnic urban industrial municipality in Melbourne. Aetiological factors and effects on infants and preschool children.

In a cohort of 99 families with a newborn infant in a multi-ethnic poor socio-economic municipality 35 mothers were depressed during the first year. While the clinical manifestations of depression in Australian-born and immigrant mothers were similar, there were differences in some aetiological factors. Immigrant mothers who had recently arrived in Australia, were unable to speak English and did not have a supporting social network had a significantly higher rate of depression. Depressed Australian-born mothers often had unhappy, unstable and insecure childhoods, having been reared in families with marital disruption, violence, alcoholism and desertion. Some also had previous depressive episodes. A strong supporting social network, especially by the father, and also by the extended family and friends, was significant in preventing depression. Behavioural problems in infants and preschool children were more common in families with depressed mothers.

Australia↗
PubMed1985

Reproducibility of nucleolar measurements in human intraocular melanoma cells on standard histologic microslides.

The standard deviation of nucleolar area (SDNA), as determined by semiautomated measurement of routinely prepared histologic sections, has been shown to be an effective predictor of mortality for human intraocular melanoma. One hundred cases of this tumor underwent two independent determinations of SDNA by each of two technicians using the same device. One technician performed the two measurements within two months, the other within three weeks. Analysis of these 400 values revealed the following: the more experienced of the two technicians achieved an acceptable level of reproducibility in determining SDNA; the less-experienced technician achieved a lower level of reproducibility; a systematic bias was found upon comparing SDNA values of the two technicians; and this bias can be partially corrected by applying a linear transform. These findings support the value of SDNA as a practical clinical measure of malignant potential for intraocular melanoma but also suggest that experience can enhance the reproducibility of a technician's measurements.

Cell Nucleolus↗
PubMed1984

DNA and enzyme studies on chorionic villi for use in antenatal diagnosis.

A study has been undertaken to determine the efficiency of current methods in providing an adequate amount of chorionic villus DNA for antenatal diagnosis using recombinant DNA techniques or enzyme assay. Chorionic biopsies were obtained from 40 women undergoing elective first trimester termination of pregnancy (8-12 weeks) under general anaesthesia. The villus tissue was isolated from maternal tissue under a dissection microscope and the presence of any remaining contamination was ascertained by conventional histology and immuno-cytochemical examinations. A high level of success was achieved in obtaining a pure fetal sample. In the first 20 samples the DNA yield obtained using the method of Williamson et al [1] was found to be 0.5 +/- 0.5 micrograms/mg wet weight of villus tissue (mean +/- 1 SD). In the subsequent 20 biopsies using a modified procedure, the yield was significantly improved to 1.0 +/- 0.65 (p less than 0.002). A normal range for the enzyme iduronate sulphatase, which is deficient in Hunter's syndrome (mucopolysaccharidosis II), is also reported. It is suggested that as little as 20 mg of chorionic villi may be used to provide sufficient material for a reliable study using recombinant DNA or biochemical methods.

Amniotic Fluid↗
PubMed1984

A model for the aging of fly larvae in forensic entomology.

A method is described for determining the time of hatching of blowfly larvae on a corpse with respect to temperature. Temperature is known to have a profound effect on the rate of growth of fly larvae, and it is suggested that past assumptions that the growth of larvae found in a corpse has taken place at one approximated ambient temperature may have led to large overestimates of the development time of the larvae, and thus overestimates of time of death. Larvae of Lucilia cuprina, Calliphora vicina (= erythrocephala), Calliphora stygia and Calliphora hilli were cultured under constant temperatures, and their growth rates modeled with a logistic growth curve. Two programmes have been developed, one to compute the parameters for the logistic equations, the other is used to estimate the time elapsed from the time at which a sample is removed from a body to the estimated hatching time of the larvae comprising the sample, with temperatures and species as variables.

Animals↗
PubMed1984

Central effects of dopamine on vasopressin release in the normally hydrated and water-loaded rat.

The effect of intracerebroventricular (I.C.V.) micro-injections of dopamine on vasopressin (AVP) release was investigated in normally hydrated and hydrated rats anaesthetized with urethane, hormone concentrations being determined by radioimmunoassay. Dopamine given in doses of less than 25 micrograms had little effect on AVP concentrations already elevated as a result of anaesthesia and surgery. Doses of over 25 micrograms produced a transient increase in AVP concentrations followed by a fall. Both the increase and the fall were statistically significant. Pimozide (400 micrograms/kg) blocked the fall in AVP concentrations following dopamine. A fall was still seen after the administration of haloperidol (400 micrograms/kg) but it was only significant 20 min after the injection of dopamine. The changes in AVP concentration after the administration of naloxone (400 micrograms/kg) were not statistically significant. In water-loaded rats I.C.V. micro-injections of dopamine produced a dose-dependent antidiuresis over the range 1-25 micrograms. An injection of 25 micrograms dopamine in these animals produced an increase in AVP concentrations to 1.8 +/- 0.51 microunits/ml and a fall in urine flow which could be approximately matched by an infusion of vasopressin of 15 microunits/min. The antidiuresis in response to dopamine could be blocked by haloperidol. The response to dopamine in the anaesthetized animals depends on a number of factors including the initial activity of the neurohypophysial system.

Animals↗
PubMed1984

Effect of inhaled beclomethasone dipropionate on saliva cortisol concentrations.

Serial saliva cortisol measurements were used to assess pituitary-adrenal function in a group of asthmatic children treated with beclomethasone dipropionate (400 micrograms daily). Asthmatic children who were not being treated with steroids and normal children were also studied for comparison. A diurnal cortisol rhythm was observed in all three groups. Early morning cortisol concentrations were significantly higher in the group treated with beclomethasone dipropionate than in the normal children; this may indicate a stress induced response to decreased morning peak expiratory flow. In both groups, plasma and salivary cortisol responses after adrenocorticotrophic hormone stimulation test were normal but peak cortisol concentrations showed a 7 fold increase over basal values in saliva compared with a three fold increase in plasma. Beclomethasone dipropionate does not suppress pituitary-adrenal function in children when used in recommended doses. Serial measurement of the salivary cortisol concentration is a simple, safe, and sensitive method for the routine monitoring of adrenal function in children treated with this steroid. Monitoring may be supplemented with an assessment of the adrenal response to adrenocorticotrophic hormone stimulation, if necessary.

Adolescent↗
PubMed1984

Social class and ischaemic heart disease: use of the male:female ratio to identify possible occupational hazards.

In England and Wales there has been an increasing excess of ischaemic heart disease death rates among men and women of social classes IV and V compared with those in classes I and II and this excess is greater in young than in old adults. The male excess over women in IHD death rates is much greater in social classes I and II than in classes IV and V. Although men in professional occupations are at low risk for IHD compared with men in other occupations, women married to professional men are at an even lower risk compared with other women. Also, women married to men in unskilled occupations have relatively higher IHD rates than their husbands. These patterns are not seen for "all causes," cerebrovascular disease, chronic bronchitis, or stomach cancer, where the social class mortality gradients are similar in men and women. There may thus be factors associated with professional occupations that increase the risk of IHD despite the relatively low death rates of men engaged in them. In addition there may be factors operating in women in social classes IV and V that put them at a particularly high risk for the development of IHD.

Adult↗