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Biomedical subjects

J Wilkinson

Publications and source records attributed to J Wilkinson.

At least 181 records · Page 10Linked to original sources
PubMed1986

Bladder base dosage in patients undergoing intracavitary therapy.

The maximum dose rate being delivered to the base of the bladder during intracavitary therapy was assessed in 20 patients by CAT scanning during treatment. This value was compared with the I.C.R.U. bladder reference point dose rate calculated from lateral radiographs taken after insertion. The ratio of the maximum bladder base dose rate to the I.C.R.U. reference dose rate varied from 1.01 to 3.59. In ten patients the maximum bladder dose rate was not in the midline. Re-examination of five patients revealed significant changes in bladder base dose rate in two due to changes in applicator positioning and packing. The bladder base dose rate on the vertical plane through the middle of the vaginal ovoids was within +/- 25% of the maximum bladder base dose rate in 22/25 examinations.

Adult↗
PubMed1986

The role of the macula densa in renin release: studies by microperfusion.

The role of the macula densa in control of renin release and in mediation of tubulo-glomerular feedback was investigated following orthograde microperfusion in Munich Wistar rats. Tubules of surface glomeruli were perfused, drip-fixed with glutaraldehyde and biopsy cores taken containing perfused and non-perfused glomeruli. Serial sections were examined by light and electron microscopy. In some animals dilated basolateral spaces were observed between cells in control maculae densa but no spaces were found following microperfusion with hypertonic NaCl, isotonic mannitol or hypotonic NaCl containing 1 mg/l frusemide. In other animals no spaces were found in control cores, and perfusion with the above solutions had no effect. However, in such animals, tubules perfused with hypotonic NaCl (71 mmol/kg H2O) had prominent basolateral spaces in their maculae densa. The presence of dilated basolateral intercellular spaces is generally associated with osmotically driven water flow. The extent of dilatation of such spaces in the macula densa is correlated with transepithelial osmotic or ionic gradients and may indicate activity of these cells in the recognition of distal tubular fluid composition.

Animals↗
PubMed1986

A novel approach for obtaining and identifying monoclonal antibodies that react with differentiation-specific antigens using human hybrid cells.

HeLa X keratinocyte hybrid cells have been used as immunogens to generate monoclonal antibodies against differentiation-specific antigens. A key feature of the experimental system is that the hybrid cells are undifferentiated in culture and yet terminally differentiate in the mouse. The properties of these cells allow one a facile approach to obtaining and characterizing monoclonal antibodies against differentiation-specific antigens. Use of hybrid cells derived from HeLa X differentiated cell fusions as immunogens should prove to be a general method for identifying differentiation-specific antigens from a variety of differentiated cell types.

Animals↗
PubMed1985

X;14 translocation:an exception to the critical region hypothesis on the human X-chromosome.

We report on a family in which an X;14 translocation has been identified. A phenotypically normal female, carrier of an apparently balanced X-autosome translocation t(X;14)(q22;q24.3) in all her cells and a small interstitial deletion of band 15q112 in some of her cells had 2 offspring. She represents a fifth case of balanced X-autosome translocation with the break point inside the postulated critical region of Xq(q13 q26) associated with fertility. The break point in this case is located in Xq22, the same band as in four previously published exceptional cases. In most of her cells, the normal X was inactivated. Her daughter, the proposita, has an unbalanced karyotype 46,X,der(X), t(X;14)(q22;q24.3)mat, del(15)(q11.1q11.3)mat. She is mildly retarded and has some Prader-Willi syndrome manifestations. She has two normal 14 chromosomes, der(X), and deletion 15q11.2. Her clinical abnormalities probably could be attributed to the deletions 15q and Xq rather than 14q duplication. In most of cells, der(X) was inactivated. We assume that spreading of inactivation was extended to the 14q segment on the derivative X. Late replication and gene dose studies support this view. Another daughter, who inherited the balanced X;14 translocation and not deletion 15 chromosome, is phenotypically normal.

Adolescent↗
PubMed1985

Common evolutionary origin of the phage T4 dam and host Escherichia coli dam DNA-adenine methyltransferase genes.

We compared the known DNA nucleotide and encoded amino acid sequences of the Escherichia coli and bacteriophage T4 dam (DNA-adenine methyltransferase) genes. Despite the absence of any DNA sequence homology, there were four regions (11 to 33 residues long) of amino acid sequence homology containing 45 to 64% identity. These results suggest that the genes for these two enzymes have a common evolutionary origin.

Adenine↗
PubMed1983

The outcome of prolonged labor as defined by partography and the use of oxytocin: a descriptive study.

A descriptive study of 300 consecutive spontaneous labors in primigravid patients whose pregnancies were of 37 or more weeks' gestation with a singleton fetus in the vertex presentation, showed a cesarean section rate of 13%, a forceps delivery rate of 49%, and a spontaneous delivery rate of 38%. Oxytocin was used in 17% and epidural analgesia was used in 75% of the patients. The median rate for cervical dilatation for those women with spontaneous deliveries was 2 cm/hr (interquartile range = 1.5 to 3.3 cm/hr) and for those delivered with forceps, 1.2 cm/hr (interquartile range = 0.9 to 1.8 cm/hr). When labor was prolonged by 4 hours or more, the cesarean section rate rose to 34%. Oxytocin was used in only 41% of these patients. Of 23 women delivered by cesarean section for dystocia/disproportion, only nine received oxytocin. From the low incidence of low Apgar scores in all labor groups from this series, there would not appear to be a fetal advantage to earlier intervention. Although the suggestion from this study is that oxytocin administration when labor is prolonged by 4 hours will reduce the need for cesarean section, the true value of such an intervention can be tested only by a randomized controlled trial.

Adolescent↗
PubMed1981

Prader-Willi Syndrome after age 15 years.

Twenty-four patients, all of them over 15 years, with the Prader-Willi syndrome are described. Obesity, often extreme, associated with an insatiable appetite, was their principal handicap and this was made worse by educational subnormality and hypogonadism. Three of the them developed diabetes. Each attended a special school or an adult training centre. Although most of them were of short stature and had scoliosis, 2 were tall but they even more severely mentally retarded than is usually the case. Nine other patients died aged between 3 and 23 years. The most common cause of death was cor pulmonale.

Adolescent↗
PubMed1980

Tonsillectomy and childhood Hodgkin's disease.

The relation between previous tonsillectomy and Hodgkin's disease was examined in a case-control study involving 81 histologically confirmed childhood cases and two sibling control groups. When cases were compared with age-matched sibling controls a significant association (p < 0.02), with a risk of 2.7, was observed for children who had undergone tonsillectomy. A significant association (p < 0.01), with a relative risk of 2.5, was also shown when all siblings were used for comparison. History of hospital admissions, age at tonsillectomy, Rye histological subtype, birth order, and sibship size did not appear to modify the effect of this operative procedure on the risk of Hodgkin's disease.

Adult↗
PubMed1980

Dissociation of anchorage independence form tumorigenicity in human cell hybrids.

The association between anchorage independence and tumorigenicity was examined using a series of intraspecific human cell hybrids. The cell lines represented non-tumorigenic HeLa/fibroblast hybrids and tumorigenic segregants derived from them. These segregants had lost no more than 5% of the original chromosome complement. Both non-tumorigenic and tumorigenic cell populations formed colonies in methyl cellulose. The relative size of the colonies seemed to be inherited as a stable trait. Serial cloning of nontumorigenic hybrids in methyl cellulose led to an enhanced efficiency of colony formation but no selection for tumorigenic segregants. Thus, the property of anchorage independence is clearly dissociated from tumorigenicity in this human cell system. An ancillary observation was the chromosomal stability of the hybrids over many population doublings. This intraspecific human cell model therefore provides a genotypically and phenotypically stable system for examination of the genetic control of transformation and neoplasia.

Animals↗