The use of the single radial haemolysis technique in the serological diagnosis of dengue and Japanese encephalitis virus infections

The single radial haemolysis test for the serological diagnosis of suspected dengue and Japanese encephalitis virus infections uses crude virus antigens with a haemagglutinin titre of 1:320 or 1:640. The results, which may be read 3 hours after the addition of a patient's serum, showed a general agreement between this test and haemagglutination-inhibition tests in the number of case diagnoses that were confirmed. The antibody responses of individual patients shown by the two tests, however, were different, which suggests that the two tests may not be measuring the same antibody. The single radial haemolysis test can distinguish between dengue and Japanese encephalitis viruses using specific mouse hyperimmune sera. Tests on a limited number of sera from Japanese encephalitis patients also showed no cross-reactions with dengue virus antigens in those cases having a low-titred but significant fourfold antibody rise to Japanese encephalitis antigen.

HLA-system in Chinese children with insulin-dependent diabetes mellitus: a strong association with DR3

We studied the distribution of HLA-A, B, and DR and MT1, MT2, MT3 genotypes in all 20 Chinese children with insulin-dependent diabetes mellitus (IDDM) attending the four government pediatric units in Singapore. We found an increase in HLA BW22 but the corrected probability value was not statistically significant. AW33 and B17 were observed in 50% and 55% of IDDM children, respectively, compared with 11% and 13% of normal controls, respectively. The values for AW33 were as follows: corrected P = 0.00094 and relative risk (RR) = 8.17; for B17 they were corrected P = 0.001 and RR = 7.55. In addition, the frequency of DR3 was 50% in IDDM children compared with 14% of normal controls (corrected P = 0.0019, RR = 6.20). AW33, B17, and DR3 are in linkage disequilibrium in our normal Chinese population. All ten patients who were positive for DR3 also had B17. The frequency of DR4 was not increased, and there were no protection IDDM related antigens found. These differences compared with the results in Western populations may contribute to the relative rarity of IDDM among Chinese children.

HLA system in Chinese children with insulin-dependent diabetes mellitus

HLA in 12 unrelated Chinese paediatric patients with insulin dependent diabetes mellitus (IDDM) were found to have an increased frequency of BW22, B17 and AW33. BW22 was observed in 5/12 (41.7%) of IDDM patients compared to 40/330 normal unrelated Chinese controls (p less than 0.005, rr = 5.2). AW33 and B17 were observed in 6/12 (50.0%) and 7/12 (58.3%) of IDDM patients respectively, compared to 36/330 and 46/330 in the normal controls respectively (AW33: corrected p less than 0.0026, RR = 8.2, B17: corrected p less than 0.0026, rr = 8.6). HLA B8, B15 and B18 did not demonstrate any significant association with IDDM in this series of patients. The results of this study further emphasize the well recognized race specificity in HLA antigen distribution in normal population as well as disease states.

The development of critical care medicine in Singapore

The development of critical care medicine in Singapore is similar to that in other countries. The fact that intensive care work was not centralised meant that anaesthetists had to attend to patients who were to be found all over a large hospital. Moreover, up to 1967, there was only one ventilator in the Singapore General Hospital although this was commonly used. When open-heart surgery was restarted in 1967, the need for intensive care in the post-operative patients became obvious and a post-basic intensive care nursing course was subsequently started. The quest for an area to centralise intensive care also stepped up and as space in certain wards were generously given toward this cause, intensive care further developed. With the opening of the new Singapore General Hospital, critical care medicine is certainly ready to move toward an even more sophisticated standard.

Pathogenicity of nonpigmented cultures of Chromobacterium violaceum

Nonpigmented cultures of Chromobacterium violaceum have been found to be similar to pigmented cultures in their virulence for mice and the pathology of their infections. Clinicians and microbiologists should be prepared to consider nonpigmented C. violaceum in their differential diagnoses of infections caused by gram-negative bacteria. The laboratorian who is not aware of this possibility is likely to erroneously identify nonpigmented strains of C. violaceum as members of closely associated genera, particularly Aeromonas. It is known that violet pigmentation is not an essential feature or an exclusive character of the genus Chromobacterium. This study has also shown that pigmentation of C. violaceum is not related to its pathogenicity or to the pathology of its infections.

Histological and histochemical observations on the neurosecretory cells in the diencephalon of Chthonerpeton indistinctum and Ichthyophis paucisulcus (Gymnophiona, Amphibia)

In the diencephalon of two species of Gymnophiona (Amphibia) two neurosecretory nuclei were examined with histological (Alcian Blue, Aldehyde Fuchsin, Brookes Trichrome stain) and enzyme histochemical techniques (acid phosphatase, alpha-naphthyl acetate esterase, acetylcholinesterase (AChE)). In the preoptic nucleus two categories of secretory neurons were distinguished: large and medium sized neurons. The perikarya of both cell types contain very little neurosecretory material. The Alcian Blue method stained the medium sized neurons faintly but selectively. The tractus praeopticohypophyseus is marked by the presence of Herring bodies, which, however, are relatively scarce. The neurohypophysis, in contrast, contains large amounts of neurosecretory material. Both cell types of the preoptic nucleus are characterized by their very strong AChE and alpha-naphthylacetate esterase activity. The AChE also marks the tractus praeoptico-hypophyseus. In the large neurons acid phosphatase is present around the nucleus; in the medium sized neurons this enzyme is concentrated close to the origin of the axon. In the dorso-caudal hypothalamus a small group of neurons is stained with Alcian-Blue. These neurons, which also contain AChE, are located immediately under the ependyma which seems to be specialized in this region.