Search PubMed⌕ Search

Biomedical subjects

R Henderson

Publications and source records attributed to R Henderson.

At least 163 records · Page 9Linked to original sources
PubMed1987

Etiology and clinical course of missed spine fractures.

A prospective study was designed to document course and outcome. Two hundred fifty-three patients with 274 spinal injuries were reviewed at the time of injury and discharge from hospital, as well as at 1, 2, and 5 years postinjury. Thirty-eight of these patients were identified who had been misdiagnosed at the initial assessment. Fracture location, cause of injury, neurologic deficit, and delay in diagnosis were all documented: 22.9% of cervical injuries, and 4.9% of the thoracolumbar injuries had a delayed diagnosis ranging from less than 1 day to 36 days. The causes of delayed diagnosis were: 1) failure to take X-rays, 2) fractures missed on X-ray, and 3) failure of patients to seek medical attention. Associated factors such as intoxication of the patient, multiple injuries, level of consciousness, or two levels of spinal injury contributed to the delayed diagnosis of these injuries. Certain "at-risk" populations for missed spinal injuries have been identified. In spite of delays in diagnosis, progression of an established neurologic deficit did not appear to occur in our study. However, the development of secondary deficits was significant in the delayed diagnosis group.

Accidents, Traffic↗
PubMed1987

Specific and nonspecific immunoregulatory factors and renal transplantation.

From a study population of 208 consecutive first cadaver renal transplant recipients a proportional hazard model was used to simultaneously quantify the role in graft failure of matching for specific HLA antigens and constitutional factors (age, sex, duration of dialysis (Dt), and pre- (PTr) and peri-(PerTr) operative transfusions) that influence nonspecific immune response. A comparison was also made of graft survival in patients treated by the two principal methods of dialysis, hemodialysis (HD) and continuous ambulatory peritoneal dialysis (CAPD). The advisability of including nonimmunological failures in studies of graft survival was also considered. The analysis indicated that factors influencing a patient's innate nonspecific immune response (e.g., Dt and PTr) are important determinants of graft survival and should be taken into account when considering matching for specific HLA-B or DR antigens prior to transplantation. While there was no overall effect of dialysis type on graft survival, the influence of other risk factors depended on the method of dialysis. Failure to identify and exclude graft loss for nonimmunological reasons can give rise to misleading conclusions in analysis of immunoregulatory factors in organ transplantation.

Blood Transfusion↗
PubMed1987

Psychoeducational findings among children treated for phenylketonuria.

Early treated phenylketonuric children who maintained a phe-restricted diet through age 10 were compared with those who discontinued the diet after age 6 on standardized tests of intelligence, school achievement, language, and perceptual skills. Mean IQ, reading, and spelling test scores improved between ages 6 and 10 for the on-diet children in comparison to those who were off diet. Mean scores on arithmetic, language, and perceptual skills, however, declined at a uniform rate for both groups. Children with PKU scored significantly lower than did their non-PKU siblings on tests of visual perception and visual-motor skills. We conclude that children with PKU should be maintained on a phe-restricted diet.

Achievement↗
PubMed1986

Morbidity patterns in a general paediatric unit in rural Western Australia.

Admissions to the Medical Paediatric Unit at Derby Regional Hospital in 1984 were reviewed. There were 536 admissions (289 males and 247 females). The average number of inpatients per day was 11.7, average duration of stay was 8.0 days, and there was one hospital death. Aboriginal children represented 90% of admissions and 59% of these were under two years of age. Several major problems were often encountered in individual children; these included respiratory, gastrointestinal and renal disease, failure to thrive and anaemia. Plasma electrolyte levels were measured in 82 children with gastroenteritis. Of these children 45 (55%) had a serum potassium level of less than 3.0 mmol/L and eight (10%) had a serum potassium level of less than 2 mmol/L. One hundred and four children were diagnosed as having pneumonia; 74 (71%) of them responded to penicillin. In 19 (21%) of 92 children who failed to thrive, no definite medical cause was found. The remainder had a combination of diarrhoeal disease, and chest and urinary tract infections. Anaemia, renal calculi and rheumatic fever are also common medical problems in the Kimberley region.

Australia↗
PubMed1986

Use of salicylate with high pressure liquid chromatography and electrochemical detection (LCED) as a sensitive measure of hydroxyl free radicals in adriamycin treated rats.

Hydroxyl free radicals react with salicylate to form 2,3-dihydroxybenzoic acid (2,3-DHBA) and 2,5-dihydroxybenzoic acid (2,5-DHBA). Utilizing the technique of high pressure liquid chromatography with electrochemical detection (LCED), it is possible to detect DHBAs at the level of femtomoles. Since salicylate is relatively non-toxic, we have administered it as a trapping agent in a first attempt to examine the use of the LCED method as a sensitive measure of in vivo OH production. Utilizing adriamycin administration as a model to induce oxygen free radical tissue damage, we found that the level of DHBAs present in drug treated rats versus controls was increased 100-fold in heart and muscle, 30-fold in lung, and 3- and 4-fold in brain and blood, respectively. These first observations support the theory that adriamycin induces OH in tissue and indicates that the LCED method may prove to be useful to measure oxygen free radical production in vivo.

Animals↗
PubMed1986

Electron diffraction analysis of the M412 intermediate of bacteriorhodopsin.

High resolution electron diffraction data have been recorded for glucose-embedded purple membrane specimens in which bacteriorhodopsin (bR) has been trapped by cooling slowly to below--100 degrees C under continuous illumination. Thin films (OD approximately 0.7) of glucose-embedded membranes, prepared as a control, showed virtually 100% conversion to the M state, and stacks of such thin film specimens gave very similar x-ray diffraction patterns in the bR568 and the M412 state in most experiments. To be certain that any measured differences in diffraction intensity would be real, two independent sets of electron diffraction intensities were recorded for near-equatorial, i.e. (hkO), reflections. Little correlation was indeed observed between these two sets for delta F values at low resolution (15-5.0 A, 49 reflections), but the correlation coefficient is approximately 0.3 at high resolution (5.0-3.3 A, 218 reflections). Thus, while most of the measured difference is error, the mean delta F and the correlation coefficient can be used to estimate the smaller, true delta F due to structural changes occurring in the M state. The magnitude of this estimated true mean delta F is equal to what would be produced if approximately five to seven nonhydrogen atoms were moved to structurally uncorrelated (i.e., new) positions in the M state. Movements of a few amino acid side chains, and repositioning of atoms of the retinal group and the associated lysine side chain after trans-cis isomerization, are the most probable causes of the observed intensity changes in the M state. The difference Fourier map, calculated in projection at 3.5-A resolution, shows only very small peaks, the largest of which are confined, however, to the region of the protein.

Bacteriorhodopsins↗
PubMed1986

Renal acid-base metabolism after ischemia.

The response of the kidney to ischemia-induced cellular acidosis was followed over the immediate one hr post-ischemia reflow period. Clearance and extraction experiments as well as measurement of cortical intracellular pH (pHi) were performed on Inactin-anesthetized Sprague-Dawley rats. Arteriovenous concentration differences and para-aminohippurate extraction were obtained by cannulating the left renal vein. Base production was monitored as bicarbonate released into the renal vein and urine; net base production was related to the renal handling of glutamine and ammonia as well as to renal oxygen consumption and pHi. After a 15 min control period, the left renal artery was snared for one-half hr followed by release and four consecutive 15 min reflow periods. During the control period, cortical cell pHi measured by [14C]-5,5-Dimethyl-2,4-Oxazolidinedione distribution was 7.07 +/- 0.08, and Q-O2 was 14.1 +/- 2.2 micromoles/min; neither net glutamine utilization nor net bicarbonate generation occurred. After 30 min of ischemia, renal tissue pH fell to 6.6 +/- 0.15. However, within 45 min of reflow, cortical cell pH returned and exceeded the control value, 7.33 +/- 0.06 vs. 7.15 +/- 0.08. This increase in pHi was associated with a significant rise in cellular metabolic rate, Q-O2 increased to 20.3 +/- 6.4 micromoles/min. Corresponding with cellular alkalosis was a net production of bicarbonate and a net ammonia uptake and glutamine release; urinary acidification was abolished. These results are consistent with a nonexcretory renal metabolic base generating mechanism governing cellular acid base homeostasis following ischemia.

Acidosis, Renal Tubular↗
PubMed1986

Prenatal diagnosis of a congenital mesoblastic nephroma. A case report.

Fetal urinary tract malformations are diagnosed frequently with ultrasonography. There are many published papers on in utero detection of fetal cystic abnormalities. In this case the prenatal diagnosis of a solid kidney mass was made, and histopathologic examination after surgical resection revealed congenital mesoblastic nephroma.

Adult↗
PubMed1985

Continuous ambulatory peritoneal dialysis and renal transplantation: a five year experience.

Continuous ambulatory peritoneal dialysis is a new and increasingly popular method of routine dialysis, but its effect on renal transplantation is uncertain. A non-randomised comparison was made of the outcome of grafting in patients who had been treated before transplantation with continuous ambulatory peritoneal dialysis with that in patients treated with haemodialysis. During the five years, 1979-84, after continuous ambulatory peritoneal dialysis was introduced to Newcastle upon Tyne 220 patients have received transplants after either continuous ambulatory peritoneal dialysis (61 patients) or haemodialysis (159 patients). During follow up no significant differences occurred in survival of patients or grafts between the two treatment groups. One year after transplantation the percentages of survivors who had received continuous ambulatory peritoneal dialysis and haemodialysis were 88% and 91% respectively, and overall graft survival was 66% and 72%, respectively. A multiple regression model was used to allow for differences among patients--for example, duration of dialysis and number of preoperative transfusions--on the survival of grafts. When only first cadaver grafts were considered (in 152 patients) graft survival (non-immunological failures excluded) was not significantly different between the patients treated with continuous ambulatory peritoneal dialysis and haemodialysis. Continuous ambulatory peritoneal dialysis is not a risk factor in renal transplantation, and its continued use in treatment of potential renal graft recipients is recommended.

Adolescent↗
PubMed1985

Partial cytochrome oxidase (aa3) deficiency in chronic progressive external ophthalmoplegia. Histochemical and biochemical studies.

Biochemical and histochemical studies were carried out on 2 patients with chronic progressive external ophthalmoplegia (CPEO). Histological examination revealed prominent ragged-red fibres in the Gomori trichrome stain and cytochrome oxidase staining revealed partial depletion of cytochrome oxidase with negative staining in some fibres with prominent subsarcolemmal mitochondrial aggregations. Polarographic studies with isolated intact skeletal muscle mitochondria revealed low State III respiration rates with NAD- and FAD-linked substrates. Cytochrome aa3 levels were depressed in the one case where a cytochrome difference spectra was recorded. Cytochrome oxidase levels were greatly depressed in muscle homogenate, whereas monoamine oxidase levels were in the normal range, indicating a selective depletion of the former enzyme complex. It is possible that deficiency of cytochrome oxidase may arise as an epiphenomenon in degenerating mitochondria rather than a primary deficiency.

Adolescent↗
PubMed1985

Structural comparison of native and deoxycholate-treated purple membrane.

Lipid-depleted purple membrane prepared by extraction with deoxycholate has been compared with the native structure. X-ray and electron diffraction photographs show a reduction in cell dimension from 62.4 to 57.3 A, and a substantial change in the distribution of diffraction intensity compared with the native specimens. Low-dose electron microscopy has been used to obtain a projected density map of lipid-depleted membranes. The projected structure shows that the deoxycholate treatment removes a boundary layer of lipid, which in the native form separates adjacent trimers of bacteriorhodopsin. The map also provides an improved estimate of the molecular envelope of the protein. A plausible arrangement for the lipid molecules in both the native and the lipid-depleted membranes is proposed, but the precise positions of individual molecules cannot yet be specified.

Bacteriorhodopsins↗
PubMed1985

REM sleep deprivation effect on apomorphine-induced gnawing is reversed by dexamethasone.

Glucocorticoid feedback was manipulated in rats deprived of REM for six days or left undisturbed in their home cages. One half of each group received concurrent dexamethasone (400 micrograms/kg), while the other half received corn oil. On test day, rats were observed for 5 min, injected with apomorphine (0.8 mg/kg, i.p.), and again observed. Dexamethasone revealed REM-deprivation-enhanced stereotypical gnawing, but had no effect on REM-deprivation-reduced rearing, suggesting the involvement of catecholamine depletion by non-specific stress-related factors in the former REM deprivation effect.

Animals↗