Biomedical subjects

J Mahood

Publications and source records attributed to J Mahood.

23 records · Page 2Linked to original sources

PubMed1998

Changes in serum melatonin levels in response to pinealectomy in the chicken and its correlation with development of scoliosis.

STUDY DESIGN: Normal, sham, and groups of chickens subjected to pinealectomy from which serum melatonin levels were measured and correlated with scoliosis development in a period of 5 weeks. OBJECTIVES: To measure serum melatonin levels in chickens subjected to pinealectomy and control chickens and correlate findings with development of scoliosis. SUMMARY OF BACKGROUND DATA: In a previous study by others, scoliosis developed in 100% of chickens subjected to pinealectomy, and serum melatonin levels were found to be reduced. Previous results in a study by the authors showed scoliosis developing in only approximately 55% of chickens that underwent pinealectomy. METHODS: Young chickens were subjected to pinealectomy. Control groups consisted of sham operation and normal groups. Radiographs and blood samples were taken at weekly intervals to monitor scoliosis development and measure serum melatonin levels using radioimmunoassay techniques. RESULTS: Scoliosis developed in only 52% of chickens that underwent pinealectomy, but all had low levels of serum melatonin and no circadian rhythm. The chickens in the two control groups maintained normal serum melatonin levels and rhythms. CONCLUSIONS: Pinealectomy in young chickens reduces serum melatonin levels and eliminates the melatonin circadian rhythm. It can also produce scoliosis, but low levels of serum melatonin are a poor predictor of development of scoliosis.

Animals↗

PubMed1997

Characterization of the scoliosis that develops after pinealectomy in the chicken and comparison with adolescent idiopathic scoliosis in humans.

STUDY DESIGN: The characteristics of the scoliosis that develops after pinealectomy in young chickens were determined from weekly posteroanterior radiographs. These data were compared with similar data collected from human patients with adolescent idiopathic scoliosis. OBJECTIVES: To characterize the scoliosis produced in young chickens after pinealectomy and to compare these characteristics with those seen in human patients with adolescent idiopathic scoliosis. SUMMARY OF BACKGROUND DATA: Although it has been recognized that pinealectomy produces scoliosis in chickens, the characteristics of these curves have never been well described other than by simple visual descriptions. METHODS: The characteristics of the scoliosis produced in chickens after pinealectomy done 3 days after hatching were measured from radiographs taken at weekly intervals. These characteristics were compared with similar data collected from human patients with adolescent idiopathic scoliosis. RESULTS: Similarities included development of single and double curves, degree of curvature, stability of the curve, numbers of vertebrae involved, direction of rotation, and progression characteristics. Differences included wedged vertebrae in the chickens, in conjunction with curve development and increased variability in vertebrae involved. CONCLUSIONS: There are many similarities in the development of scoliosis in young chickens after pinealectomy and in children with adolescent idiopathic scoliosis. The few differences might be related to the different biomechanical properties associated with the spine in the two species.

Adolescent↗

PubMed1997

A comparison of the innervation characteristics of the lateral spinal ligaments between normal subjects and patients with adolescent idiopathic scoliosis.

Evidence is rapidly accumulating to suggest that general proprioceptive dysfunction might be a major contributing factor in the development of adolescent idiopathic scoliosis (AIS). The innervation of appropriate ligaments which has been shown to be involved in proprioceptive feedback mechanisms, has also been suggested to play a part in this sensory dysfunction. Accordingly, this study compared the innervation characteristics of lateral spinal ligaments from patients with AIS to similar measurements from control subjects. Using an antibody to neurofilament protein, Ruffini corpuscles, small and large nerve bundles, and free nerve endings were identified and their numbers and distribution patterns compared. In the control group, the innervation was found to be symmetrical between left and right sides but was more concentrated in the ventral portion of each ligament. No apparent morphological defect of the innervation was found in the lateral spinal ligaments of the scoliosis patients but the innervation densities of Ruffini corpuscles, single nerve fibres and total neural elements were significantly lower (p<0.01) than those found in normal subjects. These results suggest a possible mechanism for the production of AIS and warrant further study.

Adolescent↗

PubMed1982

Reticular erythematous mucinosis: light and electron microscopy, immunofluorescence and histochemical findings.

Five patients with reticular erythematous mucinosis were studied by skin biopsy and phototesting. Light microscopy showed a dermal mononuclear cell infiltrate (composed largely of lymphocytes), separation of collagen bundles and fragmentation of elastic fibres. Histochemical stains showed increased dermal mucin with a profile consistent with hyaluronic acid. In one case, the ultrastructural distribution of mucin was demonstrated using colloidal iron staining, electron microscopy and X-ray microanalysis. In two cases, virus-like tubular aggregates were identified in the cytoplasm of dermal endothelial cells and pericytes. Immunofluorescent staining for immunoglobulins, fibrin and complement was negative.

Adult↗

PubMedDate not supplied

Enteric pathogenic protozoa in homosexual men from San Francisco.

The prevalence of enteric protozoa was studied in a survey conducted among 150 male homosexual patients in San Francisco. All patients were from a private practice in internal medicine. Each was asked to complete a questionnaire and to submit multiple stool specimens for examination. Of this group, 47% were positive for one or more potentially pathogenic intestinal protozoa; Entamoeba histolytica was found in 36%, Entamoeba hartmanni in 35%, Giardia lamblia in 5%, and Dientamoeba fragilis in 1.3%. Symptoms were unreliable as a diagnostic index of intestinal protozoan infection. Colonization rates could not be correlated with any specific sexual technique. The large number of homosexuals at risk, combined with the potential for difficulties in diagnosis and contact-tracing, indicate the possibility that enteric pathogenic protozoa will cause future health problems in this population.

Adult↗