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Biomedical subjects

D Griffiths

Publications and source records attributed to D Griffiths.

At least 73 records · Page 4Linked to original sources

Lateral release for recurrent dislocation of the patella.

We reviewed 41 knees after arthroscopic lateral release for recurrent dislocation of the patella at a mean follow-up of four years, and graded the results according to the criteria of Crosby and Insall (1976). There were no dislocations after operation in 28 knees (68%); the less satisfactory results were in patients with subluxation of the patella on extension of the knee and those with generalised ligamentous laxity. There were no complications. A characteristic and previously unreported lesion of the patellar surface was seen in eight of the 41 knees. The results of lateral release are better than those reported for other techniques. This treatment, by either open or arthroscopic methods, is recommended.

Adult↗

Study of DTH and resistance in Mycobacterium lepraemurium infection using a T-cell line isolated from mice infected with Mycobacterium bovis (BCG).

A T-cell line of mixed phenotype (60% L3T4+, 40% Lyt-2+) was isolated from mice infected with Mycobacterium bovis (BCG). This line responded to M. lepraemurium and BCG but not to M. leprae and produced TCGF spontaneously. It also produced factors which stimulated macrophages to secrete hydrogen peroxide and superoxide anion. In vivo studies showed that only L3T4+ cells were required to transfer DTH responses and that Lyt-2+ cells suppressed this response. Both L3T4+ and Lyt-2+ cells were required to inhibit M. lepraemurium multiplication in vivo.

Animals↗

Melatonin reduces the production and secretion of prolactin and growth hormone from rat pituitary cells in culture.

A culture of clonal tumour cells from rat pituitary gland that secrete both prolactin and growth hormone were used to investigate whether the pineal hormone melatonin can act directly on the pituitary gland to control prolactin production. Melatonin inhibition of prolactin and growth hormone production was significant but mild. Concentrations of between 10(-8) M and 10(-6) M reduced both prolactin and growth hormone production and prolactin secretion by 10-50%. 17 beta-oestradiol (OE) and thyrotrophin-releasing hormone (TRH) stimulated prolactin production but had no significant effect on growth hormone production. Melatonin reduced the effects of both of these compounds. Both TRH and vasoactive intestinal peptide (VIP) stimulated secretion of prolactin, and TRH also of growth hormone. Melatonin reduced these effects significantly. TRH and VIP increased cAMP production two- and 12-fold, respectively. Melatonin had no effect on basal or stimulated cAMP production. The melatonin-induced changes in prolactin and growth hormone production and secretion seen here do not approach the magnitude of the fluctuations seen in plasma in vivo. It is concluded that while melatonin does have a direct effect on the lactotroph in the regulation of prolactin production, its main physiological target must be elsewhere.

Animals↗

Anatomical and physiological observations on supraspinal control of bladder and urethral sphincter muscles in the cat.

In 15 cats injections of 3H-leucine were made in the pontine tegmentum. Injections in the medial part of the dorsolateral pontine tegmentum (M-region) resulted in specific projections to the sacral intermediomedial and intermediolateral cell groups. The intermediolateral cell group contains preganglionic parasympathetic neurons that form the motor supply of the detrusor muscle of the bladder. Injections in the lateral part of the pontine tegmental field (L-region) produced labeled fibers in the nucleus of Onuf, which contains motoneurons innervating the pelvic floor including the anal and urethral sphincters. L-region projections to the sacral preganglionic parasympathetic neurons and M-region projections to the nucleus of Onuf were very limited or absent. In 12 cats physiological experiments were performed. Electrical stimulation in the L-region elicited a prompt increase in the pelvic floor EMG and urethral pressure but had little influence on the intravesical pressure. Stimulation in the M-region elicited a prompt decrease in the pelvic floor EMG and urethral pressure followed, after a delay of 2 seconds, by an increase in the intravesical pressure, so simulating normal micturition.

Animals↗

Reversibility of cyclosporin nephrotoxicity after three months' treatment.

86 renal allograft recipients were randomly assigned to cyclosporin (Cy) for 90 days followed by azathioprine and prednisolone (Aza and P), or to Aza and P from day 0, as part of the second Oxford trial of short-term Cy use. All 62 patients whose grafts functioned for at least 120 days were included in this study. Serum creatinine was significantly higher in Cy-treated patients than in control patients from day 28 to day 90. Serum uric acid was also significantly higher in Cy-treated patients over the same period. Both creatinine and uric acid fell to the level of the control group after conversion to Aza and P. Serum uric acid was significantly higher for a given level of creatinine during Cy treatment than in either the control patients or the Cy-treated patients after their treatment had been changed to Aza and P. These data imply that Cy affects both the glomerular filtration rate and renal tubular function but that these effects are largely reversible.

Azathioprine↗

The pressure within a collapsed tube, with special reference to urethral pressure.

A definition is proposed for tube pressure (the pressure within a collapsible tube in the collapsed state, e.g. the urethral pressure or the pressure in the anal or oesophageal sphincter) which conforms to the common sense view that it is a measure of the ability of the tube to prevent leakage. It is not dependent on the orientation of a measuring probe in the tube. The orientation effects which have previously been reported are due to attempted bending of a stiff measuring catheter by internally and externally applied forces. A satisfactory way of measuring the tube pressure, by slow perfusion through a thin, flexible catheter with an end hole, and of testing whether it is a meaningful concept in a given case, is proposed. It is illustrated by measurements of urethral pressure in 42 continent and incontinent females. No cases of urinary incontinence due to poor urethral sealing ability are observed, indicating that tube pressure is a meaningful concept. The theory of viscosity-limited flow through a compressive zone in a collapsible tube, on which the perfusion method of measuring tube pressure is based, is developed.

Adolescent↗

Neurosecretory cells of the lamina propria of the appendix and their possible relationship to carcinoids.

Carcinoid tumours of the appendix are generally thought to be derived from enterochromaffin cells; in-situ abnormalities of these cells are, however, rarely observed in the mucosal epithelium. One hundred appendices, removed consecutively at surgery, were stained with an alcian blue-PAS diastase-lead haematoxylin sequence and, in 69, cells were found in the lamina propria with a cellular and architectural morphology identical to those of an archetypal appendiceal carcinoid tumour. These cells appeared to contain neurosecretory granules, were diazo-positive and showed argentaffinity. They were further characterized by the localization of cytoplasmic neurone specific enolase and the presence of neurosecretory granules was confirmed by electron microscopy. These cells are designated subepithelial neurosecretory cells (SNC). It is suggested they are an integral component of the subepithelial nervous plexus and are in progenitors of appendiceal carcinoid tumours. A neuroectodermal origin of the SNC-and hence appendiceal carcinoid tumours-is proposed.

Appendiceal Neoplasms↗