National intercomparisons of I radioactivity measurements in nuclear medicine centres in India

National intercomparisons of activity measurements of ¹³¹I, a radioisotope widely used for diagnosis and therapy of thyroid related ailments, were initiated in 1979 as a quality assurance program, towards improving radiation safety procedures and related dosimetry in Nuclear Medicine Centres (NMCs) in India. Oral administration of a known quantity of radioiodine to patients requires accurate radioactivity measurements to be performed on a well-calibrated isotope calibrators. Under or over estimation of the activity due to a faulty or uncalibrated isotope calibrator could provide misleading results. Calibration of isotope calibrators and the traceablity of subsequent measurements to the national standards laboratory is one of the essential basic radiation safety requirement of the IAEA. In view of the stringent quality assurance requirements for activity measurements imposed by Atomic Energy Regulatory Board, a National Intercomparison Program was initiated and to date ten such intercomparison programs have been conducted by the Radiation Safety Systems Division, of the Bhabha Atomic Research Centre. This program has benefited the participants by making their measurements traceable to the National Primary Standards. Over the years there has been a marked increase in the number of NMCs participating in the intercomparison programs. As a result, the number of institution showing large deviation from the correct value has decreased considerably over the years. This program thus, has enabled participating NMCs to check their isotope calibrators so as to ensure proper delivery of radiation dose to the patients and hence to optimise patient exposure.     

Postnatal development of mouse alcohol dehydrogenases: agarose isoelectric focusing analyses of the liver, kidney, stomach and ocular isozymes

The postnatal development of alcohol dehydrogenase (ADH) isozymes was studied in liver, kidney, stomach and eye tissues of C57BL/6J inbred male mice using agarose isoelectric focusing and histochemical methods. Development profiles were tissue specific, with adult patterns being attained by 30 days in the liver and stomach, and by 42 days in the kidneys. Ocular ADH-C2 increased in activity at the end of the first week, corresponding to the time of eye opening in the neonate.     

Intradural spinal cavernomas.

Intradural cavernomas are rare vascular lesions of the spinal cord. Four cases of histologically verified cavernomas of the cord are reported, of which two were extramedullary and two were intramedullary in location. Progressive neurological deficit was the presenting feature in three cases while one patient had a rapid evolution of neurological deficits and was found at surgery to have had bled from the extramedullary lesion. All the patients were subjected to surgery and total excision of the cavernomas was carried out in each case. While two patients improved after surgery the other two remained static. The available literature on spinal cord cavernomas is reviewed.     

Job satisfaction and occupational stress among general practitioners — a pilot study

Questionnaires assessing levels of job satisfaction and possible sources of stress were distributed to a random sample of general practitioners in the Greater Manchester area. The highest levels of job satisfaction were reported for `intrinsic' job factors such as freedom to choose method of working, amount of responsibility and amount of variety, rather than `extrinsic' factors such as rate of pay and hours of work. The main causes of stress appeared to be interruptions of various kinds. Factor analysis revealed four major sources of stress: interruptions; emotional involvement; administrative workload and work/home interface; and routine medical work. Of these, all but routine medical work were associated with job satisfaction. It is concluded that the major sources of stress for the general practitioner are not medical, but social.     

Effect of indomethacin on intestinal water transport in salmonella-infected rhesus monkeys.

Indomethacin, a nonsteroidal anti-inflammatory agent, will abolish salmonella-induced rabbit ileal secretion when given prior to the establishment of infection. In the present study, we assessed whether indomethacin can inhibit salmonella-induced intestinal secretion when administered after infection and net intestinal secretion are well established. A physiological model of salmonellosis, salmonella-infected rhesus monkeys, was used. This model also permitted an examination of the effects of indomethacin in both the small and large intestines. The effect of indomethacin in control monkeys was also studied. Indomethacin caused a striking enhancement of net intestinal water transport in the jejunum,, ileum, and colon of salmonella-infected monkeys. These effects occurred promptly and were of sufficient magnitude in the ileum and colon to cause a reversal in the direction of net transport from net secretion to net absorption. Indomethacin also enhanced net water transport in the jejunum ileum, and colon of normal animals. These data show that indomethacin markedly enhances net intestinal water transport in both the small and large intestines of salmonella-infected monkeys, even when administered after salmonella infection and intestinal secretion are well established. Similar enhancement also occurs in the normal intestine. The mechanism(s) by which indomethacin produces these effects is not known.     

Crosslinked chitosan: its physical properties and the effects of matrix stiffness on chondrocyte cell morphology and proliferation

Chitosan [beta(1-4)-2 amino-2-deoxy-D-glucose], the natural polyaminosaccharide derived from N-deacetylation of chitin [beta(1-4)-2 acetamide-2-deoxy-D-glucose], has been shown to possess attractive biological and cell interactive properties. Recently chitosan and chitosan analogs have also been shown to support the growth and continued function of chondrocytes. In the present study, chitosan substrates are crosslinked with a functional diepoxide (1,4 butanediol diglycidyl ether) to alter its mechanical property, and the viability and proliferation of the canine articular chondrocytes seeded on the crosslinked surface are further assayed. Of interest is the impact of substrate stiffness on the growth and proliferation of articular canine chondrocytes. Crosslinked scaffolds were also subjected to degradation by chitosanase to examine the impact of crosslinking on enzyme-assisted degradation. The hydrophilicity and compression modulus of the crosslinked surfaces were measured via contact-angle measurements and compression tests, respectively. Scanning electron microscopy (SEM) and fluorescent staining were used to observe the proliferation and morphology of chondrocyte cells on noncrosslinked and crosslinked surfaces. The crosslinked chitosan was found to be nontoxic to chondrocytes and more hydrophilic. Its compression modulus and stiffness increased, which may improve the scaffold resistance to wear and in vivo shrinkage once implanted. The increased stiffness also seemed to serve as an additional mechanical stimulus to promote chondrocyte growth and proliferation. The cell morphology on crosslinked scaffolds seen by SEM and fluorescent stain was the typical chondrocytic rounded shape. The method proposed provides a nontoxic way to increase the mechanical strength of the chitosan scaffolds.     

Malassezia furfur in a case of onychomycosis: colonizer or etiologic agent?

The etiologic role of Malassezia furfur in onychomycosis is a contentious diagnostic problem because its keratinolytic ability has never been verified. This case report describes the isolation of M. furfur from the infected nails of a child clinically diagnosed with onychomycosis, and discusses the role of this organism as an etiologic agent/colonizer. The patient presented with subungual hyperkeratosis and onycholysis without associated paronychia. Budding yeast cells compatible with M. furfur were repeatedly demonstrated in KOH wet mounts of damaged nails, histopathology of hematoxylin and eosin (H&E) and periodic acid-Schiff (PAS) stained sections showed penetration of fungal elements between deeper layers of keratin, and numerous colonies of M. furfur were isolated on three consecutive occasions from nail specimens collected from different areas of hand and toenail lesions. No evidence of nail invasion by dermatophytic or nondermatophytic filamentous fungi were found by direct microscopy or culture. Microscopy and culture were negative following 12 weeks of ketoconazole treatment, which resulted in growth of healthy nail plates with normal beds. We can infer from these observations that M.furfur was an etiologic agent rather than a colonizer in the patient's nails even though direct keratinolytic character of this fungus was not demonstrated.