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Biomedical subjects

T Davies

Publications and source records attributed to T Davies.

At least 73 records · Page 4Linked to original sources
PubMed1993

Staging of gastrulating mouse embryos by morphological landmarks in the dissecting microscope.

We describe and illustrate a set of morphological landmarks for classifying mouse embryos by gross morphology from before gastrulation to the beginning of organogenesis. These landmarks are visible at the resolution of the dissecting microscope in embryos that are intact except for reflexion of Reichert's membrane. Adoption of these criteria should facilitate interpretation of both the expression patterns of genes and the consequences of experimental manipulation of embryos during early postimplantation development.

Animals↗
PubMed1992

The Hough transform for locating cell nuclei.

A method of cytologic image segmentation that works purely on the basis of geometric information is described. Cell nuclei are assumed to be circular or elliptical. The latest ellipse-finding Hough transform is then used to locate the nuclei. The results are encouraging.

Cell Nucleus↗
PubMed1991

Computerisation of primary care in Wales.

OBJECTIVE: To obtain information about the computerisation of general practice in Wales, and to enable more effective planning of educational provision for doctors and other primary health care workers. DESIGN: Postal questionnaire sent to all general practices in Wales. SUBJECTS: 553 general practices, of which 401 (73% replied). RESULTS: The level of computerisation varied from 11 (85%) of practices in Powys Family Health Services Authority to 22 (40%) in Mid Glamorgan. Less than half of practices had a computer in only two authorities. The commonest uses of the computer were for patient registration (208 practices), repeat prescribing (180), call and recall of patients (165), and partial clinical records (122). The main suppliers were VAMP (78 practices), AAH Meditel (46), and AMC (23). 102 of 226 practices with a computer had a terminal on each doctor's desk. Just 33 practices had full patient notes on computer and 51 had modems for electronic communication. CONCLUSION: Mechanisms to encourage greater and more sophisticated use of computers and information technology need to be explored.

Ambulatory Care Information Systems↗
PubMed1991

Oral poliovirus vaccine in the United States: molecular characterization of Sabin type 3 after replication in the gut of vaccinees.

Derivatives of Sabin 3 shed from recipients of oral poliovirus vaccine in the United States (U.S.) were examined for genetic changes identified in strains excreted by vaccinees in the United Kingdom [U.K.; Evans et al., 1985; Cammack et al., 1988, Macadam et al., 1989]. Among the eight primary vaccinees studied, the duration of excretion and molecular evolution of type 3 strains varied greatly. The period of virus excretion after vaccination ranged from as few as 2 days to as many as 36 days. Nucleotide sequence analysis of viral RNAs extracted from shed virus indicated that only fifty percent of the vaccinees exclusively excreted strains in which the attenuating mutation at nucleotide 472 in the 5' noncoding region of the genome had reverted from uracil (U) to cytosine (C), the nucleotide found in neurovirulent strains. Compared to the wild-type Leon strain, the low activity of stool isolate KW4 in a complete monkey neurovirulence test demonstrated that presence of C at 472 does not render a type 3 strain pathogenic. Conversely, an isolate was identified which efficiently replicated in monkey nervous tissue and maintained the attenuated U at 472. Oligonucleotide fingerprinting and sequence analysis of viral RNAs from stool isolates indicated that one vaccinee (KW) eventually excreted intertypic recombinant strains consistent with those reported in the U.K. studies. Unique to this study, one vaccinee (KS) excreted nonrecombinant virus possessing U at 472 for up to 21 days. The significance of the KS strain profile in relation to differences in the U.S. vaccine compared to the vaccine distributed in the U.K. and other countries is discussed.

Animals↗
PubMed1988

Peroxisomes in pigment epithelium and Müller cells of amphibian retina possess D-amino acid oxidase as well as catalase.

In this paper we identify peroxisomes in Müller cells and retinal pigment epithelial cells of Rana pipiens and Xenopus laevis by virtue of their content of cytochemically stainable catalase. These organelles have the form of an extensive, branched system of tubules in the retinal pigment epithelium and appear as discrete ovoid structures in the Müller cells. In both the pigment epithelium and the Müller cells a second peroxisomal enzyme, D-amino acid oxidase, can be detected in the same structures as catalase by means of a cerium-based cytochemical staining procedure. This oxidase is active only against nonpolar and polar, uncharged D-amino acids.

Animals↗
PubMed1988

Nuclear medicine studies of aging--III. Radial bone mineral content by single and dual photon absorptiometry.

Measurement of bone mineral content of the radius has been possible by single photon absorptiometry. Recently, dual photon devices have become widely used for measuring the quantity of lumbar vertebral bone mineral. Therefore, we studied the utility of a dual beam machine for quantifying the bone mineral content of the radius, and compared results with those obtained by single photon absorptiometry in the same patient on the same day. There was an excellent correlation between single and dual beam measurements of the radius. The present study indicates that a dual photon machine can be used for assessing not only vertebral, but radial bone mineral content as well. This may facilitate studies of the two sites by use of one machine.

Adolescent↗
PubMed1988

Nuclear medicine studies of aging--VI. Dual photon absorptiometry and bone scans in "at risk" women with back pain.

We studied 20 women who were at risk for osteoporosis (postmenopausal, or on dialysis, or on steroids), who presented with severe back pain. Patients underwent a dual photon (153Gd) densitometry study of the L2-L4 vertebrae, as well as an emission bone scan (99mTc-MDP). The dual photon method revealed abnormal results (20% or more below the mean expected value) in 13/20 patients (65%), and below the "fracture threshold" in 15/20 (75%). The emission bone scan delineated abnormal foci of uptake in 15/19 (79%). We conclude that women at risk for osteoporosis, who present with severe back pain, are likely to have a positive bone scan due to compression fracture or other derangements related to bone demineralization.

Adult↗
PubMed1986

Accident department or general practice?

Ninety two patients, who were registered with one general practice partnership that has a tradition of providing minor trauma services and who had attended a hospital accident and emergency department, completed a questionnaire giving their reasons for not first attending their general practitioners with their ailments. Most had not tried to contact their general practitioner, and of these, only a few were unsuitable for treatment first by the general practitioner. More than half had attended the accident and emergency department because they did not want to bother their own general practitioner or thought that their problem was unsuitable for his attention. A higher proportion had attended for reasons of perceived speed or convenience. In the light of the need to cut costs in the hospital service and of government interest in promoting a wider range of services in general practice further study of such problems is needed. Patients' perceptions of the role of the accident department need to be changed if present behaviour is to be altered.

Emergencies↗
PubMed1986

Anterior pituitary response to thyrotrophin releasing hormone in senile dementia (Alzheimer type) and elderly normals.

Sixteen patients with senile dementia of the Alzheimer type (SDAT) were compared with 11 age-matched normal subjects with respect to their responses of thyrotrophin (TSH) and prolactin (PRL) to thyrotrophin releasing hormone (TRH) challenge. Both groups showed a continuing rise in TSH response at 60 min, and no difference was found between the groups. A significantly exaggerated PRL response at 20 min was found in the SDAT group. There was no difference between sexes with respect to either the TSH or PRL response. These findings, albeit preliminary, may have implications for dopaminergic impairment in SDAT.

Aged↗
PubMed1984

Volatile products from acetylcholine as markers in the rapid urine test using head-space gas-liquid chromatography.

Head-space gas--liquid chromatographic analyses of cultures of all Proteus spp. showed that the production of trimethylamine from acetylcholine could be the marker for the detection in 3.5 h of significant numbers of P. mirabilis, P. vulgaris, P. rettgeri and P. inconstans A in the rapid test for Escherichia and Klebsiella spp. in urine specimens. Trimethylamine was not detected in cultures of five other urinary pathogens. Six of fifteen strains of K. aerogenes produced trimethylamine from acetylcholine but were distinguished from Proteus spp. by ethanol production from arabinose. Ethyl acetate was produced from acetylcholine by P. mirabilis, P. vulgaris, P. rettgeri, P. inconstans A, P. inconstans B, E. coli, K. aerogenes and Streptococcus faecalis.

Acetates↗