Biomedical subjects
Publications and source records attributed to M J Robinson.
Ocular trauma from nylon line lawn trimmers is becoming more prevalent. Previous case reports have described penetrating trauma caused by these tools. We managed three cases of fungal keratitis caused by injuries from nylon line trimmers. Fungal keratitis should be strongly considered as the cause of any corneal ulcer related to trauma from a nylon line lawn trimmer.
Post-ischaemic changes in forskolin and D1 dopamine receptor (labelled with SCH23390) binding sites were evaluated in a rat unilateral middle cerebral artery occlusion (MCA) model. The changes in binding were assessed acutely (2 h post-MCA occlusion) in relation to local cerebral blood flow (lCBF) and chronically (24 h post-MCA occlusion) in relation to histopathological alterations. Two hours following occlusion lCBF was significantly reduced throughout the territory of the MCA. Despite the widespread hypoperfusion, significant reductions in binding were only observed in the dorsolateral caudate nucleus--the region with the most profound reduction in blood flow (6% of the control contralateral lCBF value). Forskolin binding sites were reduced to 40% of the contralateral value while D1 binding sites were reduced to 80% of the contralateral value. Analysis of the relationship between forskolin binding and CBF in the caudate nucleus revealed that the ischaemic threshold for alteration in forskolin binding sites 2 h after MCA occlusion was approximately 34 ml/100 g/min. Twenty-four h post-occlusion forskolin binding sites were further reduced in the dorsolateral caudate nucleus (to 6% of contralateral) while D1 binding showed minimal reduction from that observed at 2 h. The areas of reduced binding corresponded to the area of histopathological change in the caudate nucleus and rostral neocortex. In conclusion, reduction in forskolin binding progresses further than reduction in D1 binding within the first 24 h following focal cerebral ischaemia. For both forskolin and D1 binding sites, the areas of reduced binding 24 h post-MCA occlusion predicted the area of histopathological change.
A previous study (M.J. Robinson, B.A. Martin, T.D. Gootz, P.R. McGuirk, M. Moynihan, J.A. Sutcliffe, and N. Osheroff, J. Biol. Chem. 266:14585-14592, 1991) demonstrated that novel 6,8-difluoroquinolones were potent effectors of eukaryotic topoisomerase II. To determine the contribution of the C-8 fluorine to drug potency, we compared the effects of CP-115,955 [6-fluoro-7-(4-hydroxyphenyl)-1-cyclopropyl-4-quinolone-3-carboxylic acid] on the enzymatic activities of Drosophila melanogaster topoisomerase II with those of CP-115,953 (the 6,8-difluoro parent compound of CP-115,955). Removal of the C-8 fluoro group decreased the ability of the quinolone to enhance enzyme-mediated DNA cleavage approximately 2.5-fold. Like its difluorinated counterpart, CP-115,955 increased the levels of cleavage intermediates without impairing the DNA religation reaction of the enzyme. Removal of the C-8 fluorine reduced the ability of the quinolone to inhibit topoisomerase II-catalyzed DNA relaxation. In addition, the cytotoxicity of CP-115,955 towards Chinese hamster ovary cells was decreased compared with that of CP-115,953. These results demonstrate that the C-8 fluorine increases the potency of quinolone derivatives against eukaryotic topoisomerase II and mammalian cells. Further comparisons of CP-115,955 with CP-115,953 and CP-67,804 (the N-1 ethyl-substituted derivative of the difluoro parent compound) indicate that the two intrinsic activities of quinolone-based drugs towards topoisomerase II (i.e., enhancement of DNA cleavage and inhibition of catalytic strand passage) can be differentially influenced by alteration of ring substituents. Finally, correlations between the biochemical and cytological activities of these drugs suggest that the ability to inhibit catalytic strand passage enhances the cytotoxic potential of quinolones towards eukaryotic cells.
The length of stay of preterm babies discharged from a neonatal nursery was determined and the predictive value of perinatal factors on the duration of stay was assessed on 762 preterm Salford born babies admitted to Hope Hospital neonatal unit between April 1986 and November 1990. The data were analysed using multiple logistical regression and forward stepwise regression analysis. Babies were discharged at a median (quartile range) postconceptional age of 36.3 (35.3-37.6) weeks. Seventeen factors were found to be strongly predictive of discharge date. The most significant predictive factor was gestational age accounting for 40% of variability compared with respiratory difficulties (6%), low birth weight (4%), sepsis (2%), and metabolic problems (1%). Most babies are discharged at approximately the same postconceptional age despite variations in their clinical course. Gestational age at birth is the most powerful predictive factor of time of discharge.
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The effect of cows' milk protein (CMP) on the mucosal disaccharidases was investigated in 23 infants with acute infective enteritis. Jejunal biopsies performed before and after cows' milk provocation were subjected to histological examination and to mucosal disaccharidase enzyme (lactase, sucrase, and maltase) analyses. After milk challenge, changes in mucosal histology were observed in 18 infants, in 17 of them the levels of all 3 mucosal disaccharidases were much reduced. 10 of these infants developed diarrhoea and, in 6, the stools were positive for reducing sugar. It is concluded that CMP has a deleterious effect on the jejunal mucosa of young infants recovering from infective enteritis, so that in the management of young infants with sugar intolerance secondary to infective enteritis, CMP and lactose should be excluded from the diet.
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Cows' milk protein enteropathy is recognised as a significant cause of persistent diarrhoea and malabsorption in young infants, but there are as yet no generally accepted diagnostic criteria. A combined clinical and histological approach to the diagnosis of cows' milk protein-sensitive enteropathy has been used in 15 patients, and the following set of criteria are proposed. (1) Clinical disease (diarrhoea with or without vomiting) while receiving cows' milk protein. (2) Clinical improvement on a diet free of cows' milk protein. (3) Normal or mildly abnormal histology of jejunal mucosa when taken 6-8 weeks after symptoms subside. (4) Histological relapse, with or without clinical relapse, after re-exposure to cows' milk protein.
The possible role of cows' milk protein in prolonging diarrhoea in very young infants with acute infective enteritis was studied in 14 infants, 9 under the age of 2 months and 5 older than 6 months. Bacterial pathogens were isolated from the stools of 4 infants from the younger age group. After appropriate initial treatment the infants were maintained on a cows' milk protein-free formula. 6 weeks later jejunal biopsies were performed before and 24 hours after challenge with a low lactose cows' milk protein formula. The immunoglobulin and complement levels in the serum and duodenal juice were also estimated at these times. Attempts to isolate bacterial and viral pathogens in stools were again made in all patients. The 5 older infants clinically tolerated cows' milk protein and their pre- and postchallenge jejunal biopsies were within normal limits. However, significant histological changes were observed in the postchallenge jejunal biopsies of all 9 infants under 2 months of age. In addition, 5 of these infants developed diarrhoea. This suggests that the jejunal mucosa of very young infants previously fed a cows' milk protein-based formula and who contract infective enteritis suffers damage when rechallenged with cows' milk protein.
A new metronidazole derivative, Tiberal (Ro-07-0207, Roche Laboratories), was evaluated in 22 children with Giardia lamblia infection. Seven patients received an oral dose of 1 g twice daily for one day; the remaining 15 patients received a single dose of 50 mg/kg. Parasitological cure was noted in all 22 patients. Significant side effects were observed only in those children who received the drug at the higher dosage regime. The present study also confirms the findings of other authors that a mucosal imprint method is more reliable than examination of stools, duodenal juice or jejunal biopsy material for the detection of G. lamblia infection.
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All of 16 infants with neonatal meningitis treated during a 30-month period were found to have accompanying ventriculitis at the time of the initial ventricular puncture. Fifteen of these infants were caused by gramm-negative organisms. All infants received antibiotics systemically and intraventricularly via an implanted ventriculostomy reservoir or by direct ventricular injection. Antibiotic concentrations within the ventricular fluid were monitored during chemotherapy; the complications encountered during treatment are discussed. Fifteen infants survived the infection; of these, seven infants were normal at follow-up examinations. In our experience intraventricular chemotherapy as an adjunct to systemic administration of antibiotics has greatly reduced the mortality rate in neonatal meningitis.
Clinical observations and gross and microscopic morphology of the hearts of 50 patients who dies at various intervals following aortocoronary saphenous vein bypass procedures are presented. Time of total cardiopulmonary bypass varied inversely with survival time among these patients. Myocardial necrosis with contraction bands and/or hemorrhagic myocardial necrosis was observed in the hearts of 44 of the 50 patients. Pathogenesis of the acute myocardial necrosis with contraction bands was multifactorial: anoxic arrest, cardiotonic drugs, electrical defibrillation, electrolyte imbalance, microthrombi, and hypoperfusion are incriminated. Subendocardial hemorrhagic necrosis was present in 17 of 40 patients whose postoperative survivals were four days or less. Its frequency increased with duration of survival. Hypoperfusion of the myocardium is suggested as the major etiologic factor of the subendocardial hemorrhagic necrosis. Myocardial lesions observed among these 50 patients did not differ from those in patients who had open-heart surgery for other reasons.