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Biomedical subjects

R Knight

Publications and source records attributed to R Knight.

At least 73 records · Page 4Linked to original sources
PubMed1998

The new variant form of Creutzfeldt-Jakob disease.

A new phenotype of Creutzfeldt-Jakob disease termed new variant Creutzfeldt-Jakob disease (nvCJD) was first described in March 1996. This differs from other forms of CJD in terms of its epidemiology, clinical features and neuropathology. To date 24 cases of this new form of CJD have been described, 23 within the UK. This article describes nvCJD discussing clinical and epidemiological features and discusses possible links with the bovine spongiform encephalopathy epidemic in cattle in the UK.

Adult↗
PubMed1997

The effect of pregnancy on cyclosporine levels in renal allograft patients.

OBJECTIVE: To assess the effects of pregnancy on cyclosporine levels in six renal allograft patients. METHODS: Maternal demographic, laboratory, clinical, and perinatal outcome data were recorded in six pregnant women with previous renal allografts receiving cyclosporine immunosuppression. The cyclosporine and serum creatinine levels were measured before pregnancy, during each trimester, and postpartum. RESULTS: The mean (standard deviation [SD]) maternal age was 29.1 (3.8) years. Parity ranged from 0 to 3. Mean serum creatinine levels tended to be lower during pregnancy than before or after, as did the mean cyclosporine levels. After adjusting for dose, five of six patients had declines in cyclosporine level during pregnancy. The mean (SD) gestational age at delivery was 37.5 (2.8) weeks with a mean (SD) birth weight of 2837 (538) g. CONCLUSION: Pregnancy in patients with renal allografts can lead to a substantial decline in cyclosporine levels.

Adult↗
PubMed1997

Level of education, age of bearing children and mental health of women.

The present study examined the longitudinal relationship between women's mental health and both their level of education and age at which they had their first child. The women were divided into four groups depending on whether or not they had further education after leaving school and whether or not they had a baby before the age of 21. Longitudinal data collected over a 19-year period from this group of women suggested that psychological morbidity was relatively stable across this time span. Women who left school without proceeding to further education and those who became mothers before the age of 21 had higher psychological symptom scores than the other groups throughout this period. These two factors were associated with poorer mental health in an additive fashion. The women were also more likely to have separated from the father of their child and continued to be economically disadvantaged into mid-life.

Adult↗
PubMed1997

Thoracoscopic excision of mediastinal parathyroid adenomas: a report of two cases and review of the literature.

BACKGROUND: Most abnormal parathyroid glands can be removed through a standard cervical incision; even those in the superior mediastinum. Those located in certain areas of the mediastinum, for example posteriorly or in the aortopulmonic window, historically have required excision through a median sternotomy or thoracotomy. Angioablation is a nonsurgical alternative to management of these lesions. STUDY DESIGN: We present two case reports of mediastinal parathyroid adenomas that were excised thoracoscopically, and review the literature regarding the management of mediastinal parathyroid adenomas. RESULTS: Both patients who underwent precise localization and thoracoscopic excision of their mediastinal parathyroid adenomas had resolution of their hypercalcemia with minimal associated morbidity and shortened recovery periods. CONCLUSIONS: We suggest that thoracoscopic excision of mediastinal parathyroid adenomas is the better means of controlling hypercalcemia secondary to parathyroid adenoma in those patients considered for either median sternotomy, thoracotomy or angiographic ablation where the exact location of the lesion can be established preoperatively.

Adenoma↗
PubMed1997

Creutzfeldt-Jakob disease in the elderly.

Creutzfeldt-Jakob disease (CJD) is typically described as a pre-senile dementia. However, cases do occur in the elderly and a case of sporadic CJD in an 86-year-old patient is described. The database of the UK national surveillance unit has been studied, and the age-specific incidences for various age groups over the period 1980-93 calculated. Cases of CJD in those over 80 years old have been identified and their clinical characteristics examined. There is no evidence that CJD presents atypically in the elderly, or that large numbers of cases are being missed in the elderly due to poor ascertainment.

Adult↗
PubMed1996

Contribution of human hippocampal region to novelty detection.

The ability to respond to unexpected stimuli (the 'orienting response') is a fundamental characteristic of mammalian behaviour, but the brain mechanisms by which novelty is detected remain poorly defined. Electrophysiological recordings of scalp and intracranial event-related potentials (ERPs) have shown that novel stimuli activate a distributed network involving prefrontal and posterior association cortex. In addition, ERP and single-neuron recordings, as well as neuroimaging and modelling studies, have suggested that temporal cortical regions, including the hippocampus, are also involved. To examine further the role of the medial temporal lobe in novelty processing, I measured physiological responses to novel auditory and tactile stimuli in patients with damage to the posterior hippocampal region. In normal control subjects, unexpected novel stimuli produce a characteristic ERP signal, accompanied by an autonomic skin response. Both responses are reduced in hippocampal lesion patients, whereas the response to expected control stimuli is unaffected. Thus the hippocampal region, in addition to its known role in memory formation, is an essential component of the distributed limbic-cortical network that detects and responds to novel stimuli.

Aged↗
PubMed1995

Bancroftian filariasis in Kwale District of Kenya. III. Quantification of the IgE response in selected individuals from an endemic community.

One hundred and sixty-two individuals from a community in Kwale District, Kenya, endemic for bancroftian filariasis, were selected for a study on the IgE response to filarial antigen (prepared from adult Brugia pahangi). Following clinical and parasitological examination, the individuals were grouped into different categories, based on the presence/absence of microfilaraemia, the presence/absence of acute or chronic (hydrocele or elephantiasis) clinical manifestations, and age. The total and filarial-specific IgE responses were evaluated in all individuals, and the responses in the various categories were compared with each other and with the responses of control groups of individuals from filariasis-free areas. The majority of individuals from the endemic area had highly elevated serum concentrations of total IgE. Overall and within each clinical category, the concentration of total IgE was higher in those individuals from the endemic area who had microfilaraemias than in those that did not. The majority of individuals from the filariasis endemic area also had significantly elevated levels of filarial-specific IgE. In contrast, the concentration of specific IgE was lower in subjects with microfilariae than in those without, irrespective of their clinical status. Only a small proportion of total IgE was filarial-specific, the mean value varying from 0.4% to 9.8%, depending on category. Among the endemic individuals, the mean proportion of total IgE which was filarial-specific was 3.6 times higher in the microfilaria-negative than in the microfilaria-positive, indicating that much of the filarial-induced IgE in microfilaraemic individuals could be non-specific. No clear relationship was observed between the IgE response and the clinical manifestations or age of the endemic individuals.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1994

Partial additivity of rod signals with M- and L-cone signals in increment detection.

Test additivity experiments revealed the combination rules for increment detection by rods and either M- or L-cone-dominated mechanisms isolated by means of chromatic adaptation (Stiles' pi 4 and pi 5, respectively). Increment thresholds were measured for single test wavelengths detected by each mechanism. Pairs of test wavelengths were then superimposed, and increment thresholds were measured for simultaneous detection by both rod and cone mechanisms. The observed degree of additivity was corrected (reduced) to compensate for the partial detection by each mechanism of both test wavelengths in the combined stimuli. We find that subthreshold rod signals are partially additive with subthreshold signals from both M- and L-cones. The degree of additivity is high and similar for both M- and L-cones: less than the ideal prediction of linear addition, but greater than that predicted by either probability summation of independent mechanisms or orthogonal vector addition.

Color Perception↗
PubMed1994

Bancroftian filariasis in Kwale District of Kenya. I. Clinical and parasitological survey in an endemic community.

A cross-sectional parasitological and clinical survey for Wuchereria bancrofti infection was carried out in an endemic community of south-eastern Kenya, to obtain background epidemiological information for detailed serological studies on bancroftian filariasis in the same community. Quantitative examination of night blood samples (100 microliters) from 1129 individuals (76% of the population), using the counting chamber technique, revealed circulating microfilariae in 13.7% of the study group. Prevalence increased with age, and was higher in males (15.9%) than in females (11.6%). The geometric mean intensity among infected individuals was 223 microfilariae/ml blood (336 microfilariae/ml for males and 212 microfilariae/ml for females). Approximately 16.5% of the males aged > or = 15 years had hydrocele and 2.4% of the population had elephantiasis. The prevalence of these conditions increased with age; in those aged > or = 50 years, 23.8% of males had hydrocele and 6.1% of the total population had elephantiasis. Acute cases of epididymo-orchitis, adenolymphangitis and funiculitis were also seen. The microfilarial prevalence in males with hydrocele was not significantly different from that in asymptomatic males, but none of the elephantiasis cases had microfilaraemia. The striking difference in microfilaraemia pattern between hydrocele and elephantiasis patients may reflect different mechanisms underlying the development of these two chronic manifestations. The overall prevalences of microfilaraemia and clinical manifestations in this community were moderate when compared with those found in other studies carried out along the coast of eastern Africa.

Adolescent↗
PubMed1994

Bancroftian filariasis in Kwale District of Kenya. II. Humoral immune responses to filarial antigens in selected individuals from an endemic community.

Humoral immune responses to filarial infection were investigated in 162 individuals, covering the full clinical and parasitological spectrum of bancroftian filariasis as seen in an endemic community of Kwale District, Kenya. Sera were tested for specific antifilarial antibodies (total immunoglobulins, IgM, IgGl, IgG4 and IgE) using ELISA. Most individuals showed an immunological response to the filarial antigen (prepared from adult Brugia pahangi). How these responses were related to the clinical manifestations, parasitological status and age was analysed by comparing the mean antibody levels among different categories of endemic individuals, and by comparing these to the levels in control groups from filariasis-free areas. IgM and IgE anti-filarial antibodies were detected with low specificity in unabsorbed sera. A higher specificity, clearly distinguishing the mean antibody levels in the endemic categories from those of control groups, was obtained for total specific immunoglobulins, and for IgE in sera absorbed with protein A. The most specific results were obtained for IgGl and IgG4; clear inter-category differences were observed for these classes. The mean level of specific IgG4 was significantly higher in microfilaraemic groups than in amicrofilaraemic groups, whereas the mean level of specific IgGl was significantly higher in amicrofilaraemic, symptomatic cases than in microfilaraemic, symptomatic cases. In most categories of endemic individuals, and for most antibody isotypes, the mean levels of specific antibodies tended to be higher (although not significantly) in the younger individuals than in the older individuals. Overall, the differences in the filarial antibody responses were more closely related to the presence or absence of microfilariae and to the age of the individuals than to the disease manifestations in this endemic population.

Acute Disease↗