Biomedical subjects
Publications and source records attributed to S M Chandi.
A case of delayed pulmonary metastases from an ameloblastoma of the mandible, which occurred 20 years after surgical resection of the primary tumor but with no recurrence at the primary site, is reported. Combination chemotherapy using cisplatin, adriamycin, and cyclophosphamide has produced a very good clinical and radiologically documented response in this case.
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The authors describe an unusual case of a primary chondroid chordoma arising from the base of petrous temporal bone. The patient, a young male, presented with a left sided jugular foramen syndrome. The CT findings of a tumour arising from the base of the left petrous temporal bone were confirmed at infratemporal exploration. The clinical and histopathological and immunohistochemical differences between classical (typical) chordoma and its chondroid variant are highlighted. The rarity of primary chordomas at this site is stressed.
Dorsal Root Entry Zone (DREZ) thermocoagulation using radiofrequency has successfully been employed in the treatment of various deafferentation pain syndromes. The ability of surgical lasers to produce discrete lesions with precision has prompted their use in DREZ lesioning. The effects of carbon-dioxide laser induced DREZ lesions in the primate spinal cord were studied in the Bonnet monkey and the parameters necessary to produce a histologically ideal DREZ lesion were evaluated. Lesions were made with 10, 15 and 20 Watts power for pulse durations of 100 to 400 milliseconds at a constant beam spot size of 0.4 mm. It was found that histologically ideal lesions were produced with 20 Watts of power and a pulse duration of 300 milliseconds and with 15 Watts power and 400 millisecond pulse duration. The lesion lengths and widths at different parameters were also comparatively evaluated. The postulated mechanisms of deafferentation pain and the possible mode of action of DREZ lesions in management of pain are also reviewed.
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Skin biopsies from the cutaneous lesions of seven patients with indeterminate, BT, BL, and LL leprosy of less than 1 year's duration were examined by light and electron microscopy. Inflammatory cells, which marked the location of Mycobacterium leprae in bacilliferous cases (BL and LL) were most frequently and consistently found in relation to dermal blood vessels, neurovascular bundles, nerves, arrector pili muscles, and skin adnexa. The number of bacilli and inflammatory cells in the epineurium was in great excess of those in the perineurium and endoneurium. Perineurial infiltration by lymphocytes and bacillated macrophages was seen to occur through gaps between the constituent cells of a loosened and sometimes proliferated perineurium. Bacillation of Schwann cells and associated inflammation in the endoneurium was minimal. M. leprae were identified in endothelial cells, arrector pili muscles, macrophages and Schwann cells. At this stage, inflammatory destruction of nerve fibers was not encountered. It is concluded that M. leprae which are extruded from the circulation into the epineurium (or perineurium) may be carried in inflammatory cells across the perineurium which is loosened and rendered permeable to inflammatory cells as a consequence of chronic inflammation in the adjacent epineurium. This is suggested as a very probable route for M. leprae to enter nerves.
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Crushed rabbit tibial nerves were inoculated with a suspension of living Mycobacterium leprae at and just distal to the site of nerve trauma. The resulting changes occurring over a period of time from 40 min to 72 hr post-inoculation were studied electron microscopically. Bacilli were seen in perineurial cells and in macrophages that had infiltrated the perineurium adjacent to epineurial deposits of M. leprae. It is suggested that trauma may weaken the perineurial barrier and facilitate the transperineurial passage of phagocytes, some of which may be laden with M. leprae, and may thus be a means whereby M. leprae enter the endoneurium of peripheral nerves.
A case of amoebic meningitis, presumably primary, was encountered in the Christian Medical College Hospital, Vellore, South India, in November 1983. The patient, a 40-year-old man, had cerebrospinal fluid rhinorrhea before the meningitis developed. Acanthamoeba culbertsoni was repeatedly demonstrated in and cultured from the cerebrospinal fluid. The patient responded dramatically to a combination therapy of penicillin and chloramphenicol.
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In leprosy, the occurrence of necrotizing nodular lesions in peripheral nerves is a relatively uncommon complication. Despite clinical and gross similarities, there are microscopical differences among groups of such cases, indicating that in all probability different pathogenetic mechanisms are operative. Furthermore, the vast majority of such cases are not true abscesses but are characterized by caseous necrosis and granulomatous inflammation. The traditional collective name "nerve abscess" is therefore inappropriate. Presented herein is an analytic study of 30 cases of the commonest variant, which we suggest should be called segmental necrotizing granulomatous neuritis of leprosy (SNGN). This lesion commonly affects the right ulnar nerve just above the elbow and occurs most often in those with the borderline tuberculoid form of leprosy. It appears to represent the result of a hypersensitivity phenomenon marked by a preponderance of epithelioid cells rather than a reaction of immunity in which lymphocytes predominate. Acid fast bacilli were demonstrable in the lesion in 77% of cases.
The ultrastructural changes that develop in mouse peritoneal macrophages from 10 minutes up to 14 weeks after exposure to Mycobacterium leprae are presented. Phagocytosis occurred by a process of engulfment by cytoplasmic processes and incorporation into a phagosome, into which lysosomal enzymes were subsequently introduced. Electron transparent zones (E.T.Z.) were not observed around phagocytosed bacilli in this study, however discrete droplets of lipid-like material appeared in the cytoplasm of macrophages, between 2 and 4 weeks after ingestion of the micro-organisms. Phagosomes with double limiting membranes were observed in macrophages harvested as early as 40 minutes after exposure to M. leprae, contrary to the observations of Evans and Levy (1972).
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An unusual case of bilateral Krukenberg tumors having a predominant multicystic mucinous component which on gross and microscopic examination resembled a mucinous cystadenocarcinoma is presented. It is important to distinguish between these two tumors as Krukenberg tumours have a significantly worse prognosis.