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Biomedical subjects

R Pathmanathan

Publications and source records attributed to R Pathmanathan.

At least 55 records · Page 3Linked to original sources

Microscopically diagnosed head and neck cancers in the University Hospital, Kuala Lumpur.

A retrospective study of 1000 cases of microscopically diagnosed head and neck cancers in the University Hospital, Kuala Lumpur was done. Head and neck neoplasms comprise 7.1% of all tumours diagnosed in this Hospital and the commonest sites of involvement are the nasopharynx (29.1%), cervical lymph nodes (22.6%), oral cavity (10.2%), thyroid (8.2%) and skin (6.5%). Histologically, 87% of tumours are epithelial in nature. The results of this study show that nasopharyngeal carcinoma is commonest in Chinese males, while oral and laryngeal malignancies occur more frequently in Indians.

Asian People↗

Immature teratoma of the ovary.

Results of treatment of 9 cases of pure immature teratoma of the ovary seen at the University Hospital, Kuala Lumpur, are presented. Six patients were in Stage 1 and three in Stage 3. A majority of them had grade 2 or 3 tumors. Four patients in Stage 1 had the conservative surgery of salpingo-oophorectomy performed, the more radical procedure of total hysterectomy, bilateral salpingo-oophorectomy omentectomy, and tumor debulking where feasible being carried out in the others. Adjuvant chemotherapy consisted of either pulsed cyclophosphamide, VAC (vincristine, actinomycin D, and cyclophosphamide) or PVB (cis-platinum, vinblastine, bleomycin) regimes. Seven patients have survived for periods up to 9 years with no clinical evidence of disease.

Adolescent↗

Anorectal melanoma.

Four cases of anorectal melanoma are presented. The authors believe that this is the first report of the occurrence of this tumour in Malays. Advanced disease at initial presentation accounts for the poor prognosis observed in this series. Surgery remains the principal treatment modality, although controversy exists regarding optimal extent of resection.

Adult↗

Tuberculous liver abscess.

Tuberculous liver abscess is uncommonly seen in our experience. We report a case of a 17-year-old boy who presented with typical clinical features of liver abscess, where a diagnosis of tuberculous liver abscess was made on laparotomy and biopsy of the abscess wall.

Adolescent↗

Sandwich nucleic acid hybridization: a method with a universally usable labeled probe for various specific tests.

Nucleic acid hybridization is widely used for scientific applications but essentially restricted to specialized laboratories. The use of recombinant m 13 phages as hybridization probes (Hu and Messing (1980) Gene 17, 271; Messing (1983) Methods Enzymol. 101, 20) offers a considerable advantage over the commonly used recombinant plasmids as the preparation of the DNA probe is very simple and it can easily be labeled directly, e.g. with isotopes with long half-life like 125I (Commerford (1971) Biochemistry 10, 11 (1983); Gu et al. (1983) Cancer (China) 2, 129; Han and Harding (1983) Nucleic Acids Res. 11, 14) and used for hybridization. However, as the application of nucleic acid hybridization for diagnostic and epidemiological purposes becomes almost unavoidable, the logistic problems of keeping numerous individually labeled hybridization probes increase considerably and may reach prohibitory levels in less well-equipped laboratories. In a new sandwich technique, the first step involves hybridization with an unlabeled recombinant m 13 DNA carrying an insert of the desired specificity. In a second step a universally usable labeled probe directed against the m 13 part of the recombinant phage DNA is applied. This reduces considerably the problems of preparing and keeping multiple labeled probes in stock.

Bacteriophages↗

Suppression of cell-mediated immunity following oral feeding of mice with palmyrah (Borassus flabellifer L) flour.

Inbred mice fed with a 40% mixture of palmyrah flour pellets showed a significantly reduced capacity to mount a delayed-type hypersensitivity (DTH) response to sheep red blood cells (SRBC). Maximal suppression of DTH was noted after 6 days of feeding but was detectable even after 2 days. Maximal suppression occurred when flour feed was maintained into the sensitization period (with SRBC). The suppressive effect was transferable to normal mice fed with pellets ad libitum by viable spleen cells from mice fed with the 40% flour pellet mixture for a period of 2 days. Further characterization of the cells which were able to transfer suppression showed them to be T cells, some of which possess the Ly-1 surface antigen. The cells appear to be negative for Ly-2 surface antigen. Histologically, no evidence of lesions was noted in the liver and other organs of recipient mice which received cells from flour-fed donors. We thus favour the interpretation that oral feeding of mice with palmyrah flour induced the generation of T suppressor cells which were able to suppress the DTH response to SRBC. The significance and implications of these findings are discussed.

Animals↗

New developments in nucleic acid hybridization.

Nucleic acid hybridization is widely used for scientific applications in specialized laboratories. This paper describes hybridization probes that can be prepared with less specialized equipment. A new indirect 'sandwich' hybridization test is described which allows the use of only one universally usable labelled probe for hybridization tests with specificities for various sequences. The use of different labels and hybridization techniques is also discussed and critically compared. For in situ hybridization, the usability of fixed and embedded materials is tested and evaluated.

DNA, Viral↗

Cryptococcosis in the University Hospital, Kuala Lumpur and review of published cases.

Between January 1974 and June 1980, 85 cases of cryptococcosis were diagnosed in the University Hospital, Kuala Lumpur, Malaysia. The diagnosis was based on positive culture of the organism in 81 cases; the remaining four were diagnosed on histopathological findings. Cerebral cryptococcosis was the most common presentation and Chinese are particularly susceptible (72% of cases). The incidence of the disease is shown to be far greater than previously suspected. Association with compromised host status is uncommon (14%). The local literature is briefly reviewed and the findings discussed.

Adult↗

Induction and characterization of delayed-type hypersensitivity to dengue virus in mice.

Delayed-type hypersensitivity (DTH) to dengue virus type 4 in mice is described. The DTH reaction (measured by footpad swelling) was maximal at 24 hr after challenge and was enhanced significantly when mice were pretreated with cyclophosphamide. The response was maximal six days after infection with an immunizing dose of approximately 10(7.3) 50% lethal doses per mouse. Histologic examination of the test footpad showed a predominantly mononuclear cell infiltrate at 24 hr after challenge. fibrin deposition was also noted. DTH reactivity was transferable to normal mice by injection of immune spleen cells but not of immune serum. The DTH reaction was apparently specific for dengue virus type 4 because significantly lower responses were detected when dengue virus types 1-3 and Japanese encephalitis virus were used as challenge antigens in mice infected with dengue virus type 4. The probable importance and significance of these findings in relation to the host immune response and the pathogenesis of dengue virus infection are discussed.

Animals↗