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Biomedical subjects

R Knight

Publications and source records attributed to R Knight.

At least 55 records · Page 3Linked to original sources
PubMed2000

The pulvinar sign on magnetic resonance imaging in variant Creutzfeldt-Jakob disease.

BACKGROUND: There is a need for an accurate non-invasive diagnostic test for variant Creutzfeldt-Jakob disease (vCJD). We investigated the sensitivity and specificity of bilateral pulvinar high signal on magnetic resonance imaging (MRI) for the diagnosis of vCJD. METHODS: MRI from patients with vCJD and controls (patients with suspected CJD) were analysed. Scans were reviewed on two separate occasions by two neuroradiologists and scored for the distribution of changes, and likely final diagnosis. Scans from vCJD cases were reassessed to reach a consensus on all abnormalities. FINDINGS: We analysed 36 patients and 57 controls. vCJD patients were correctly identified based on bilateral pulvinar high signal in 29 of 36 and 32 of 36 cases on the first assessment by the two radiologists, and 32 of 36 and 31 of 36 on their second assessment. Bilateral increased pulvinar signal was identified in one of 57 and one of 57 controls on the first assessment and two of 57 and three of 57 controls on the second assessment. These reported changes in controls were graded as minimal/equivocal in six of seven patients and moderate in one (<0.5% of all control assessments). 80% of the assessments in vCJD cases were graded as moderate or substantial. On consensus review, 28 of 36 cases and none of 57 controls had prominent bilateral pulvinar signal-sensitivity 78% (95% CI 60-90%) and specificity 100% (95% CI 94-100%). Other common MRI features of vCJD were medial thalamic and periaqueductal grey matter high signal, and the notable absence of cerebral atrophy. Pulvinar high signal correlated with histological gliosis. INTERPRETATION: In the appropriate clinical context the MRI identification of bilaterally increased pulvinar signal is a useful non-invasive test for the diagnosis of vCJD.

Adolescent↗
PubMed2000

Extent of misclassification of death from Creutzfeldt-Jakob disease in England 1979-96: retrospective examination of clinical records.

OBJECTIVE: To investigate the extent to which deaths from Creutzfeldt-Jakob disease were misclassified during 1979-96. DESIGN: Structured review of clinical records based on predetermined criteria to determine whether death could have been due to sporadic or variant Creutzfeldt-Jakob disease. SETTING: 100 health authorities and 275 NHS trusts in England. SUBJECTS: 1485 people who died aged 15-44 years from selected neurological disorders in England during 1979-96. MAIN OUTCOME MEASURE: Cause of death. RESULTS: The clinical records of 705 (48%) subjects were successfully traced. Tracing of clinical records was highest in subjects who died during 1990-6. There was sufficient information in the records of 640 (91%) of the 705 subjects to exclude Creutzfeldt-Jakob disease as a cause of death. In 61 (9%) subjects, there was insufficient information to reach any conclusion about the validity of the cause of death recorded on the death certificate. The clinical records of four subjects were examined further by the National Creutzfeldt-Jakob Disease Surveillance Unit; none was thought to have died from Creutzfeldt-Jakob disease. CONCLUSIONS: No new cases of sporadic or variant Creutzfeldt-Jakob disease were detected in a sample of deaths most likely to have included misclassified cases. This suggests that the surveillance system is unlikely to have missed a significant number of cases among people aged 15-44 years. Hence, any rapid increase in the number of cases of variant Creutzfeldt-Jakob disease in this age group is likely to be real not artefactual.

Adolescent↗
PubMed2000

Haemolytic disease of the newborn due to anti-Ce.

A baby was readmitted to the hospital 3 days after delivery when she developed jaundice. At admission, the direct antiglobulin test was also found to be positive. The baby required emergency exchange transfusion. A strongly reacting IgG anti-Ce (Rh7) was found in the serum of the mother. Severe haemolytic disease of the newborn due to anti-Ce is very rare. The mother's serum had been screened and found negative for red cell antibodies at 16 weeks gestation but the test was not repeated later in pregnancy when this antibody might have been detected.

Adult↗
PubMed2000

A glutamine insertion in the 1A alpha helical domain of the keratin 4 gene in a familial case of white sponge nevus.

White Sponge Nevus (WSN) is a rare, autosomal dominant disorder that predominantly affects noncornified stratified squamous epithelia. Clinically, it is characterized by the presence of soft, white, and "spongy" plaques in the oral mucosa. The characteristic histopathologic features are epithelial thickening, parakeratosis, and vacuolization of the suprabasal layer of oral epithelial keratinocytes. Mutations in keratin 4 (K4) and keratin 13 (K13) genes have already been demonstrated to be responsible for WSN; the identification of new keratin mutations in a stratified squamous epithelia closely related to epidermis is of relevance for the understanding of the biochemistry of intermediate filaments, and for genotype phenotype correlations. In this study we investigated a 27-y-old, female Italian patient, affected by white asymptomatic oral plaques. Sequence analysis revealed a 3 bp (ACA) heterozygous insertion localized in the helix initiation motif of the 1A alpha helical domain of K4. We report this new K4 gene mutation and describe an amino acid insertion, in the 1A domain, responsible for a keratin disease.

Adult↗
PubMed2000

Ratings of profile attractiveness after functional appliance treatment.

The aim of this study was to determine the change in profile attractiveness in children with Class II Division 1 malocclusion after 18 months' treatment with functional appliances. Changes in profile attractiveness were assessed by panels of art students, dental students, and parents of orthodontic patients. Each panel consisted of an equal number of male and female raters. The raters first decided whether the initial or 18-month profile silhouette was more attractive, and then scored the degree to which it was more attractive on an unmarked visual analog scale. There were no significant differences between either male and female raters or among panels in their assessments of the change in profile attractiveness in the whole sample. Neither were there significant differences between the change in profile attractiveness of the untreated subjects and the subjects treated with either Fränkel function regulators or Harvold activators. It is concluded that treatment with functional appliances does not lead to more attractive profiles than nontreatment.

Analysis of Variance↗
PubMed1999

Vertebrate genome evolution: a slow shuffle or a big bang?

In vertebrates it is often found that if one considers a group of genes clustered on a certain chromosome, then the homologues of those genes often form another cluster on a different chromosome. There are four explanations, not necessarily mutually exclusive, to explain how such homologous clusters appeared. Homologous clusters are expected at a low probability even if genes are distributed at random. The duplication of a subset of the genome might create homologous clusters, as would a duplication of the entire genome. Alternatively, it may be adaptive for certain combinations of genes to cluster, although clearly the genes must have duplicated prior to rearrangement into clusters. Molecular phylogenetics provides a means to examine the origins of homologous clusters, although it is difficult to discriminate between the different explanations using current data. However, with more extensive sequencing and mapping of vertebrate genomes, especially those of the early diverging chordates, it should soon become possible to resolve the origins of homologous clusters.

Animals↗
PubMed1999

Female genital mutilation--experience of The Royal Women's Hospital, Melbourne.

This study was performed to improve our knowledge and understanding of the needs of women affected by female genital mutilation. We looked at the types of complications of these practices which present to a large metropolitan women's hospital in order to determine how we can appropriately treat and support affected women. This was an observational study of women from countries with a high prevalence of female genital mutilation who presented to the Royal Women's Hospital between October, 1995 and January, 1997. Fifty-one patients with a past history of female genital mutilation who were attending the hospital for antenatal or gynaecological care consented to participate in the study. We found that 77.6% of women identified as having had female genital mutilation had undergone infibulation. More than 85% of the women in our study reported a complication of the procedure. The major complications were dyspareunia, apareunia and urinary tract infections; 29.4% of these women required surgery to facilitate intercourse. In our study group there was no difference in Caesarean section rates between the women who had previously delivered in Australia compared with those who had delivered in Africa. Women who have had a female genital mutilation procedure have specific needs for their care which present challenges to both their general practitioners and obstetrician/gynaecologists. These women have significant complications related to their procedure including social and psychosexual problems which require sympathetic management.

Adult↗
PubMed1999

The relationship between new variant Creutzfeldt-Jakob disease and bovine spongiform encephalopathy.

Creutzfeldt-Jakob disease (CJD) has been transmitted in the laboratory and also by iatrogenic accident. However, research has failed to find evidence that its most common form (sporadic CJD) is a natural infection and, in particular, that there is a causal link with scrapie. Bovine spongiform encephalopathy (BSE) probably resulted from scrapie infection in cattle food. In the wake of the BSE epidemic, a novel clinico-pathological form of CJD has been recognized: new variant CJD (nvCJD). This paper reviews the relationship between nvCJD and BSE and presents the accumulated evidence supporting the view that nvCJD resulted from BSE contamination of human food.

Animals↗
PubMed1998

Creutzfeldt-Jakob disease: clinical features, epidemiology and tests.

Creutzfeldt-Jakob disease (CJD) is now recognized to occur in four main forms: classical sporadic, genetic, iatrogenic and new variant. These are briefly described. The evidence that new variant disease is due to bovine spongiform encephalopathy (BSE) is reviewed. In CJD, disease and infectivity are associated with the accumulation of an abnormal form of a normal cellular protein. Protein analysis and the study of the gene which encodes for this protein have therefore played an important role in understanding CJD. Diagnostic tests for CJD are discussed with particular reference to the detection of the 14-3-3 protein in the cerebrospinal fluid (CSF).

Animals↗
PubMed1998

Rods affect S-cone discrimination on the Farnsworth-Munsell 100-hue test.

Rod influence on hue discrimination was assessed by the Farnsworth-Munsell 100-hue test. Rod influence was taken as the difference in error scores obtained after complete dark adaptation and during the cone plateau at three mesopic (23, 9, 3 td) and one standard (158 td) light level. On the FM 100, rods produced a differential discrimination loss along a tritan axis as compared with a red-green axis without any bias toward a rod confusion axis. Rods appear to impair discrimination mediated by S-cone pathways, which at moderate levels of illumination can differentially elevate tritan errors on the FM 100.

Adult↗
PubMed1998

Rod influence on hue-scaling functions.

Rod influence on hue appearance of spectral lights was characterized by comparing the scaling of red, green, yellow, and blue hue sensations for an 8 degrees-diameter, 7 degrees-eccentric test spot under conditions that minimized (cone plateau) and maximized (dark adapted) rod influence at two mesopic light levels (1.5 and 3.0 log scoptic trolands). At the lower light level, the hue-scaling functions showed that rod signals influenced the spectral range and magnitude of all four primary hues. The rod influence could not be characterized as a ubiquitous augmentation or diminution of any hue over the entire spectrum. This constrains models of rod influence on color vision.

Adult↗
PubMed1998

Markers of bone resorption in patients treated with pamidronate.

Pyridinoline (PYD), deoxypyridinoline (DPD), and N-telopeptide (NTX) are markers of bone resorption. In cancer patients with bone metastases, NTX is more often elevated than either of the pyridinolines. Bisphosphonates inhibit osteoclasts and their treatment decreases skeletal complications of malignancy. The aim of this study was to correlate urinary PYD, DPD, and NTX levels with clinical events in patients receiving pamidronate. 25 cancer patients with lytic bone disease were treated with monthly pamidronate combined with endocrine or chemotherapy; 27 others were on placebo. Twenty-four hour urines were collected at baseline, 1, 3 and 6 months. NTX values were determined by enzyme-linked immunosorbent assay (ELISA); PYD and DPD values were determined by reverse phase high performance liquid chromatography (HPLC). Two hour urines were also collected weekly for 21 patients. The greatest difference as a result of pamidronate treatment was observed in NTX values. Maximum suppression was achieved 2 weeks after treatment. Of the 25 patients who received pamidronate, 21 had initially elevated NTX values. 12 of the 21 finished with normal NTX values, whilst 9/21 had NTX values which remained abnormally elevated. The proportions of patients with fractures between these two subgroups approached statistical significance (P = 0.07) while the proportions with bony disease progression were significant (P = 0.03, Fisher's exact test). Measuring NTX levels appears useful in monitoring bisphosphonate therapy of bone metastases. The goal of treatment should be to normalise NTX excretion.

Aged↗
PubMed1998

The diagnosis of prion diseases.

Prion diseases of humans and other animals have clinical, economic and political significance. Pre-mortem diagnosis is therefore of great importance. Clinical diagnostic criteria and the current status of the available diagnostic tests are reviewed and possible future developments discussed. Presently, most diagnostic tests are indirect, relying on findings that may not be confined to prion diseases rather than on their particular intrinsic nature. They are therefore not absolutely specific nor are they 100% sensitive. The electroencephalogram (EEG), cerebral imaging and cerebrospinal fluid (CSF) analysis are the main techniques employed. However, there is hope that useful blood tests could be developed which would be simpler and less invasive. Also, there is hope that more specific tests will become available.

Creutzfeldt-Jakob Syndrome↗