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Biomedical subjects

B Robinson

Publications and source records attributed to B Robinson.

At least 127 records · Page 7Linked to original sources

Does autonomic neuropathy in diabetes cause hearing deficits?

This study examined the effect of autonomic neuropathy on hearing in diabetes mellitus. Twelve diabetics with autonomic neuropathy and eleven healthy controls were examined for hearing loss using standard audiological tests. Several subjects in both groups had some abnormal hearing tests, but the incidence was no greater in the diabetic group. No group trends were apparent. Diabetic autonomic neuropathy is unlikely to be associated with hearing deficits.

Acoustic Impedance Tests↗

Hereditary agenesis of nasal cartilage. Surgical implications.

In the evaluation of a patient for cosmetic surgery, an underlying congenital origin for the deformities noted, with possible expression in multiple organ systems, should always be considered. In this case, a 19-year-old woman requesting rhinoplasty exhibited facial anomalies: lack of quadrangular and lower lateral cartilages, small bony dorsum, underdeveloped aural cartilage, and infantile larynx and trachea. Otherwise healthy, she recalled having recurrent bouts of croup until she was 15 years old, exercise limitation secondary to stridor, and a family history of nasal hypoplasia. Genetic referral diagnosed her condition as Opitz-BBB/G compound syndrome (oculogenitolaryngeal syndrome), and we here review its head and neck manifestations. Suspected agenesis of nasal cartilage, unreported in previous literature (to our knowledge), was confirmed intraoperatively and presented a unique challenge for reconstruction, including a restricted choice of anesthesia and a need for banked cartilage.

Abnormalities, Multiple↗

A genetic approach to species criteria in the amoeba genus Naegleria using allozyme electrophoresis.

The present study employs allozyme electrophoresis to characterize and inter-relate 61 isolates of Naegleria. Diploidy was confirmed, with heterozygotes observed at 29 of the 33 loci established and in all but two isolates. With a single exception, isolates clustered at two levels of similarity, either below 21% or above 52%. It is argued that such a major discontinuity provides a sound biological basis for a species concept in Naegleria. On this basis the present species-level taxonomy does not reflect the genetic diversity of the genus. The study recognized 18 genetic groups of species rank. The subspecies N. australiensis italica deserves specific rank; additional thermophilic species not closely related to N. fowleri and N. lovaniensis are recognized; and N. gruberi as currently conceived is a complex of 10 species, at least five of which are represented in the formal culture collections. Most species are genetically too different for relationships to be elucidated by allozyme electrophoresis, supporting the view that some of the times of divergence within the genus are extremely ancient.

Alleles↗

The importance of acid digestion of urine prior to spontaneous deposition of 210Po.

Historically, radiochemical analysis of 210Po in urine has used spontaneous deposition of the nuclide directly from raw urine onto a suitable metal disc. Consequently, the urinary excretion fraction for Po in some current metabolic and dosimetric models is based on studies which inherently assume that metabolized (i.e., filtered out of the blood by the kidneys) 210Po is plated with the same efficiency as tracer 210Po which has been added to urine samples. Urine samples collected after intravenous administration of 210Po citrate to two species of nonhuman primates were divided and simultaneously analyzed via two methods: the historical procedure of plating 210Po from raw urine for one sample and a method which includes the addition of 208Po tracer and sample digestion with concentrated HNO3 prior to 210Po deposition for the other sample. A more significant amount of 210Po was consistently recovered when the urine was wet ashed then when it was not wet ashed. A temporal relationship was found to describe the change in the ratio of the deposition recoveries for the two methods. Possible mechanisms for this phenomenon and its dosimetric implications are discussed.

Animals↗

Familial hypoparathyroidism due to an abnormal parathyroid hormone molecule.

The case of a 53-year-old man with familial hypoparathyroidism in the presence of circulating immunoreactive PTH is discussed. The patient responded to exogenous PTH by an increase in urinary cAMP excretion and by several post cyclase parameters including an increase in serum calcium and 1,25-dihydroxyvitamin D, an increase in urinary phosphate excretion and a decrease in urinary calcium. Immunoreactive PTH was detected in this patient's serum by three separate anti-PTH antisera. This immunoreactive PTH behaved aberrantly with these antisera. Nonparallelism to the standard curve was seen in two radioimmunoassays and the material was detected by an antiserum which preferentially binds bovine PTH. No circulating PTH binding activity was detectable. Family studies confirmed the genetic nature of the abnormality. HPLC studies revealed the presence of an abnormally hydrophobic fraction containing immunoreactive PTH. We believe these findings constitute strong evidence for the presence of an abnormal PTH molecule with reduced biological activity resulting in hypoparathyroidism.

Adult↗

Familial distal dysautonomia.

A patient is described who presented with painful feet on exercise. He had no evidence of peripheral vascular disease but did have anhidrosis and failure of vasodilatation in the hands and feet suggesting peripheral dysautonomia. Examination of his mother and a cousin and clinical histories of blood relatives suggested that his problem was a severe presentation of a familial distal dysautonomia. In other family members this was represented by dry hands and feet and variable vasomotor symptoms. This condition appeared to be autosomal dominant.

Adult↗

Staphylococcal scalded skin syndrome mimicking acute graft-vs-host disease in a bone marrow transplant recipient.

A 33-year-old man with mild acute graft-vs-host disease after an allogeneic bone marrow transplant for chronic myelogenous leukemia developed a necrolytic rash 90 days after transplant. A diagnosis of staphylococcal scalded skin syndrome was made when a skin biopsy specimen revealed a split in the granular layer and phage group 2, type 71 Staphylococcus aureus was cultured from the blood.

Acute Disease↗

Evidence for an HIV-related nephropathy: a clinico-pathological study.

The existence of an HIV-related nephropathy as a distinct disease entity is controversial. We observed a high incidence of renal disease in our AIDS patients. Of 182 patients, 59 patients (32.4%) were found to have heavy proteinuria (greater than 2 g/24 h). Of these, 24 patients had slow progression of renal insufficiency and 2 patients had rapid deterioration to end stage renal disease. There was a notable absence of hypertension in these cases. The incidence of proteinuria was similar in blacks and hispanics; however 22.8% of blacks had renal insufficiency as compared to 6.9% of hispanics. There was no difference in the incidence of heavy proteinuria between intravenous drug abusers (32.3%) and nonabusers (33.3%). Renal morphology when examined showed characteristic changes, including cytomembranous structures and virus-like particles. These changes were similar in patients with heavy or light proteinuria, though they were less severe in the latter. We conclude that a HIV-related nephropathy exist and the presence of cytomembranous structures and virus-like particles in the renal tissue raises the possibility of a viral etiology for this disorder.

Acquired Immunodeficiency Syndrome↗

Differentiation of the substrates for analgesia and vocalizations elicited by midbrain stimulation in rats: refractory period estimates.

Stimulation of periaqueductal gray sites resulted in both increased latencies to escape heated water with a tail-flick and audible vocalizations. To determine whether these two responses were the result of stimulation of the same substrates, refractory periods were estimated by delivering paired-pulse trains of stimulation. Stimulation consisted of 10 or 20 s trains of single pulses or pulse pairs. The pulse pair frequency threshold for both behaviors was determined for intra-pulse (C-T) intervals of 0.4-10 ms. The ratio of single to double pulse frequency thresholds provided an indication of relative effectiveness of the paired-pulse stimulation. For analgesia, the paired-pulse effectiveness gradually increased between C-T intervals of 2.0 and 5.0 ms, after which asymptotic effectiveness values were obtained. Thus, the estimated refractory period for analgesia was 2.0-5.0 ms. The refractory period estimate for vocalizations was shorter. Effectiveness values increased with a C-T interval of 1.2 ms and reached asymptote with a C-T interval of 2.0 ms. These results suggest that different fibers with overlapping spatial distributions contribute to analgesia and vocalizations produced by midbrain stimulation.

Animals↗

Housing conditions fail to affect the intravenous self-administration of amphetamine.

Rats were housed either in isolation or in groups of 4 for 6 weeks following weaning (21 days). After this housing period, some of the rats were tested for the acquisition of intravenous self-administration of amphetamine (0.004-0.25 mg/kg/infusion) and others were tested for the locomotor activating effects of amphetamine (0-1.0 mg/kg, IP). In the self-administration tests, both the isolated and grouped rats readily acquired the operant to obtain drug infusions and exhibited dose-dependent behavior. These results are in direct contrast to those we have obtained concerning the influence of the environmental manipulation on cocaine self-administration. In those tests, only isolated rats self-administered cocaine. The results of the locomotor tests indicated that whereas the isolated rats were consistently more active, the dose/response curves for the effects of amphetamine on activity were parallel for the rats reared under the different housing conditions. Thus the environment has specific effects on behavior which may be a reflection of specific neurochemical effects of the manipulation.

Amphetamine↗

Articular manifestations of acromegaly.

Forty-five patients with acromegaly or gigantism were reviewed for musculoskeletal abnormalities. Abnormalities of peripheral joints occurred in 74% of the patients and spinal involvement in 47%, leading to significant morbidity. Joint abnormalities most frequently affected the large joints (hips, knees and shoulders) but the wrist and hand were also involved. The radiological features of acromegalic arthropathy are described, including vertical widening of the hip joint, enthesopathy and osteophytosis. A favourable response to treatment is associated with a less severe arthropathy and a good functional outcome.

Adolescent↗

Is there a place for forearm osteodensitometry in clinical screening studies?

In order to evaluate forearm osteodensitometry for its potential to detect subjects with a low spinal mineral content and/or vertebral fractures, single-photon absorptiometry of the forearm and estimations of spinal mineral content by computed tomography were performed in 124 normal and abnormal subjects. Eighty-one per cent (22/27) of patients with vertebral crush fractures had a low spinal mineral content. In contrast, among 64 apparently normal individuals, six patients (four women, two men; 9.4%) had a low spinal mineral content. Forearm osteodensitometry showed a significant positive correlation with spinal mineral content. A forearm value in women in excess of 35 arbitrary units was associated with a spinal value of 75.1-mg equivalent dipotassium phosphate (K2HPO4) or above in 29/31 cases. A forearm value in women of 28.5 arbitrary units or lower was associated with a spinal value of 75-mg equivalent K2HPO4 or less in 20/24 subjects. While of no predictive value for the spine in patients with intermediate readings, forearm osteodensitometry is nevertheless considered a useful screening procedure for spinal osteoporosis.

Adult↗