T cell-mediated cytotoxicity against dengue-infected target cells

A cytotoxic T lymphocyte (CTL) response to dengue virus-infected target cells is described. Effector cells were generated in an in vitro secondary culture and appeared to be T cells possessing both the Lyt 1.1 and Lyt 2.1 surface antigens. A stronger CTL response was noted with the H-2k haplotype compared to H-2d, and H-2 compatibility was required between CTL and target cells. CTL generated showed some cross-reactivity with target cells infected with Japanese encephalitis virus (JEV), another flavivirus, but not with target cells infected with an alphavirus, Sindbis. The significance and importance of these findings are discussed.

Functional and ultrastructural changes of platelets in malarial infection

This paper describes changes in the circulating platelets of 25 patients with acute malaria within 2 to 6 days of onset of illness. Thrombocytopenia was observed in 10 out of 15 patients with Plasmodium falciparum infection, and in 4 out of 9 patients with P. vivax infection. One patient with a mixed infection of both species had a disseminated intravascular coagulation. Platelet antibody was detected in the sera of 8 out of 11 cases by the complement lysis inhibition technique and indirect immunofluorescence. The mean platelet antibody concentrations in the sera of 11 patients and 53 control subjects were 122.70 +/- 80.25 ng/10(7) platelets and 36.69 +/- 18.72 ng/10(7) platelets, respectively. An inverse relationship between the platelet count and platelet antibody levels in serum supported the view that thrombocytopenia in malaria may be partly immune-mediated. Platelet aggregation responses to agonists such as ADP, adrenaline, collagen and ristocetin revealed hyperactivity. Ultrastructural study of unstimulated platelets from patients revealed several changes such as centralization of dense granules, glycogen depletion, and formation of pseudopods and microaggregates, indicating in vivo activation of the platelets, which may also lead to thrombocytopenia.

Detection of specific IgM in dengue infection

A modification of the IgM-capture ELISA which can provide an early diagnosis for dengue infection is presented. The test is technically simple compared to HI and appears to be more sensitive. It has the advantage over HIT for the detection of specific IgM in that it is more sensitive and the reading of the result is not subjective. There is the possibility of the test being able to replace HI and HIT in the future.

CT-findings in cystic meningiomas

Cystic meningiomas are rare, about 10% occurring in children. Only 61 cases have been reported in the literature. Based on 6 of our own cases and the reports in the literature typical CT-findings are described and differentiating features from other cystic mass lesions discussed. If a tumour on CT shows a cystic component, is smoothly outlined, enhances markedly and is attached to the dura, then a preoperative diagnosis of cystic meningioma should be taken into account. This holds especially true if the patient is a child.

The sickle cell gene is widespread in India

The sickle cell gene was first described in India in a tribal population in the south, leading to the belief that it was confined to tribal groups. The present study confirms that it is widespread in the state of Orissa and spreads throughout Hindu society, being more common in upper and scheduled castes than in tribal groups.

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.

Lyt phenotype and H-2 compatibility requirements of effector cells in the delayed-type hypersensitivity response to dengue virus infection

The nature of effector cells which mediate delayed-type hypersensitivity (DTH) to dengue type 2 virus and the influence of the H-2 complex on the cellular transfer of DTH was investigated. The DTH effector cells appeared to consist of two types of T cells, one Lyt-1.1+, the other Lyt-2.1+ or, alternatively, an interaction between these two T cell subsets may be required for maximal expression of DTH. Cellular transfer of DTH reactivity also required compatibility at the K and D or I region of the H-2 complex. Compatibility at the D region alone was not sufficient for transfer of DTH. The significance and implications of these findings are discussed.

Induction and Ly phenotype of suppressor T cells in mice during primary infection with dengue virus

Infection of mice with dengue-4 virus produced a significant, transient immunosuppression of the delayed-type hypersensitivity (DTH) response to sheep red blood cells (SRBC). Suppression was noted on day 3 after infection, was maximal on day 5 and was no longer evident on day 13 after infection. The suppressive effect was transferable to normal mice by viable spleen cells from immune mice but not by immune serum. These cells appeared to be present in the spleens of infected mice as early as day 1 after infection and were still detectable on day 7. No evidence was obtained that suppression was mediated by a soluble factor. Further characterization of the cells which could transfer suppression showed them to be T cells possessing both Ly-1 and Ly-2 surface antigens. These data suggest that there may exist two types of T suppressor cells or that, alternatively, an interaction between Ly-1+ and Ly-2+ cells was required to produce suppression. The significance and implications of these findings are discussed.

Delayed-type hypersensitivity (DTH) response to dengue virus in mice: effect of route of sensitization and splenectomy

This study was designed to determine the role of the sensitization route and the spleen in the development of delayed-type hypersensitivity (DTH) to dengue virus in mice. DTH was measured by footpad swelling response. Strong but transient DTH was produced in cyclophosphamide (CY) pretreated mice sensitized subcutaneously (s.c.) or intravenously (i.v.) with dengue virus type 4. Subcutaneous inoculation of virus in incomplete Freund's adjuvant (IFA) further enhanced the DTH elicited. The time course of DTH generated by s.c. and i.v. sensitization were similar with the peak reactivity seen on day 6 after sensitization. Poor DTH was observed in mice given an i.p. inoculation even when CY and/or IFA were used. Intracerebral (i.c.) inoculation also sensitized mice poorly. Splenectomized mice showed enhanced DTH response when compared to intact mice. In contrast to intact mice, pretreatment of splenectomized mice with CY did not alter the DTH level. Splenectomized mice inoculated s.c. with virus in IFA showed poorer DTH than mice sensitized with virus alone.

Hemagglutination tests for tuberculosis with mycobacterial glycolipid antigens. Results in patients with active pulmonary tuberculosis before and during chemotherapy and in healthy tuberculosis contacts

Hemagglutination tests using three serologically active mycobacterial glycolipids as antigens were carried out on serum specimens from patients with pulmonary tuberculosis and from healthy family contacts of patients with tuberculosis in Singapore. A positive response to any of the three antigens was found in 82.5% of 211 patients with newly diagnosed disease and in 21% of 100 contacts. The much higher proportion of positive results in the contacts than in other groups of healthy subjects previously reported might have been due to subclinical infection with tubercle bacilli or with other environmental mycobacteria. The use of rules derived from discriminant analysis improved discrimination between patients and contacts, so that a positive result was obtained in 72% of patients and 5% of contacts. Serial positive titers during 1 yr of chemotherapy showed an initial slight increase during the first month and then a slow decrease, although conversion from a serologically positive result to a negative result was uncommon. The occurrence of widely variable patterns of response to the three antigens in different patients emphasizes the importance of using a battery of tests, each with a separate antigen.

Description and quantification of multiple family group interaction

Multiple Family Group Interaction as a method of Family Therapy is reported with reference to its development, technique and procedure. A rating system for the categorization and quantification of the therapeutic processes is discussed. The main findings of analysis of 85 sessions are presented.

Detection of mycolic acid in leprous tissue

A method is described for the extraction of mycolic acid from lepromatous leprosy tissues and from tuberculous tissues and its identification by thin layer chromatography. Verification of the mycolic acid extracted and separated by thin layer chromatography was accomplished by infrared spectroscopy. Although the presence of mycolic acid in tissues is not, in itself, diagnostic for leprosy, its demonstration in biopsy tissues might be a useful additional qualitative test if used in conjunction with clinical evidence of the disease.

Prognostic value of minimal excitability of facial nerve in Bell's palsy

Nerve excitability is useful for prognosis in Bell's palsy. Minimal excitability values (MEV) were obtained by stimulating the facial nerve and recording the effective current (mA) required to evoke a minimal visible contraction of frontalis, orbicularis oculi, orbicularis oris, and mentalis muscles respectively. Serial MEVs were performed on 100 patients with facial palsy, of whom 87 were followed for six months or to complete recovery; 61 patients were treated with steroids of whom 57 had good recovery. Serial MEVs were not only useful for prognosis, but also helpful in regulating the dosage of prednisone.

Evaluation of a serological test for tuberculosis

The agglutination test of Nicholls was found to be ineffective in diagnosing active tuberculosis. A positive result (titre of 1/125 or more) was found in the serum of 74 (70%) out of 105 patients with newly diagnosed, smear-positive pulmonary tuberculosis; 61 (62%) out of 98 healthy family contacts; and 19 (63%) out of 30 patients with non-tuberculous conditions. These findings were not due to faulty technique since the results obtained at Hammersmith were similar to those obtained by Nicholls's laboratory in the same serum samples. Twenty-seven of the tuberculous patients who had a negative result before treatment were retested two months after the start of chemotherapy but showed no evidence of a rising titre.