Lipids, apoliprotein-E genotypes and other risk factors of patients with coronary artery disease in Curacao

We studied lipids, apolipoprotein-E (apo-E) genotypes and other coronary artery disease (CAD) risk factors of 67 CAD patients (male/female ratio 5) in Curacao. Compared with 57 controls, male CAD patients had higher cholesterol, triglycerides, LDL-cholesterol, apo-B and decreased HDL-cholesterol and HDL-cholesterol/cholesterol concentrations. Other CAD risk factors were: increased fasting glucose and Hba concentration, decreased creatinine clearance, and increased prevalences of lipoprotein (a) concentration > 500 mg/l, renal disease, hyperhomcysteinaemia, diabetes mellitus type II (DM-II), positive CAD family history and cigarette smoking. Male CAD patients had higher plasma O-tocopherol. Compared with 29 female controls, female CAD patients had higher fasting plasma glucose with HbA concentrations, and prevalence of DM-II. Predicting factors for CAD development in the whole CAD group were: DM-II, cigarette smoking, apo-E/E and apo-E/E Apo-E was associated with lower HDL-and higher LDL-cholesterol concentrations. There is a need for local studies on improvement of diabetic control, reference values of lipoprotein (a) and homocysteine concentrations, on apolipoprotein (a) phenotypes, causes of hyperhomocysteinaemia, and dietary influences on CAD development in subject who carry the apo-E allele.(AU)

A model of the transmission of dengue fever with an evaluation of the impact of ultra-low volume (ULV) insecticide applications on dengue epidemics

We have developed a deterministic susceptible, exposed, infectious, resistant or removed (SEIR) model of dengue fever transmission that enables us to explore the behavior of an epidemic, and to experiment with vector control practices. Populations of both host and vector are divided into compartments representing disease status (susceptible, exposed, infectious, and , for humans, resistant), and the flow between compartments is described by differential equations. Examination of the equilibrium points leads to a formulation of the basic reproduction rate (Zo) of the dsease. With a base set of parameters, Zo=1.9 and the model realistically reproduces epidemic transmission in an immunologically naive population. Control of adult mosquitoes by ultra-low volume (ULV) aerosols is simulated by an abrupt decrease in vector densities, followed by gradual recovery of the vector population. The model indicates that ULV has little impact on disease incidence, even when multiple applications are made, although the peak of the epidemic may be delayed. Decreasing the carrying capacity of the environment for mosquitoes, and thus the basic reproduction rate of the disease, by source reduction or other means, is more effective in reducing transmission. (AU)

HLA-DQA1 and DQB1 Alleles associated with genetic susceptibility to IDDM in a black population

Transracial analysis provides a method of distinguishing primary associations between insulin-dependent diabetes mellitus (IDDM) and HLA class II alleles from those secondary to linkage disequilibrium. Blacks show DR-DQ relationships that are different from other races and are a useful group in which to investigate HLA-D region associations with IDDM. In this study, the frequencies of HLA-DQA1 and -DQB1 alleles in Afro-Caribbean IDDM and control subjects were compared. Alleles were identified with sequence-specific oligonucleotide probing. The DQA1 allele A3 was positively associated with IDDM (relative risk[RR] = 25.3, corrected P [Pc]<7.0 x 10 -6). THe DQB1 alleles DQw2 and DQw8 were also positively associated (RR = 4.7, Pc<6.5 x 10 -3 and RR = 12.3,Pc = 3.4 x 10 -3, respectively). The A1.2 and DQw6 alleles were negatively associated (RR = 0.16, Pc<3.5 x 10 -3 and RR = 0.15, Pc = 2.4 x 10 -2, respectively). These findings were compared to data from other races. The positive associations with A3 and DQw2 are consistent with all racial groups investigated. The negative association with DQw6 is present in all racial groups in which it is a common allele. These findings suggest that DQ alleles, and hence DQ molecules, may directly affect predisposition to IDDM. (AU)

Genetic susceptibility to leprosy on a Caribbean Island: linkage analysis with five markers

Our recent segregation analysis, carried out on 27 large pedigrees from a Caribbean island (Desirade), has shown the presence of recessive major gene(s) controlling susceptibility to leprosy per se and nonlepromatous leprosy, respectively. Linkage analysis was performed between each of these two detected genes and each of five markers typed in the Desirade population: HLA, ABO, Rhesus, Gm and Km. No positive significant lod score was observed. However, for leprosy per se close linkage was excluded with Rhesus and Gm (and also with ABO and HLA, considering a lower value for the frequency of the gene controlling susceptibility to leprosy per se). The highest lod score, although not significant, was obtained between the gene for nonlepromatous leprosy and ABO. Our overall results, joined with previous studies and experimental data, suggest that the gene controlling susceptibility to leprosy per se and that controlling susceptibility to nonlepromatous leprosy might be different, acting at successive stages of the immune response to infection with Mycobacterium leprae. (AU)

Trans-racial studies implicate HLA-DQ as a component of genetic susceptibility to Type 1 (insulin-dependent) diabetes

Type 1 (insulin-dependent) diabetic patients and control subjects of Afro-Caribbean Negroid racial origin were investigated by serological HLA-DR-typing and restriction fragment length polymorphism analysis using DNA probes corresponding to the DQO, DQá and DRá chain genes. Combined analysis indicated that four DR antigens are positively associated with the condition in Negroid subjects - DR3, 4, 7 and w9. DR3 and 4 are also associated in Caucasians, but the relative risk for DR3 is lower in Negroid subjects. The DR7 association is specific for the Negroid race, and DRw9 is only weakly associated in Caucasoid subjects. Restriction fragment length polymorphism analysis demonstrated a DQá restriction pattern in Negroid subjects which is absent from Caucasoid subjects. This pattern was associated with DRw9 and a subset of DR7, and was markedly increased in frequency in diabetic patients compared with control subjects (48.7 percent vs 10.4 percent respectively; p<10 -4). In the absence of this pattern, DR7 showed no positive association. DR3 in Negroid subjects was associated with two distinct DQO-DQá patterns, only one of which was positively associated with diabetes. A DQá pattern, in linkage disequilibrium with different DR antigens in different races, conferred a consistent protective effect against the development of Type 1 diabetes. Trans-racial genetic analysis thus supports a primary role for DQ in susceptibility to Type 1 diabetes. (AU)

Infectious meningitis at the University Hospital of the West Indies. Review of clinical and laboratory findings (1965-1980)

A retrospective study is reported on 215 cases of infectious meningitis seen during a 16-year period (1965-1980) at the University Hospital of the West Indies, Kingston, Jamaica. A detailed analysis was made of the aetiology, epidemiology, signs and symptoms, associated conditions, laboratory investigations, treatment regimes as well as outcome. The most common causative organism of bacterial meningitis was Streptococcus pneumoniae (29.3 percent), being seen in all age groups except in neonates. Haemophilus influenzae (23 percent) was the most frequent cause in pre-school children. Unusual pathogens constituted a major group of bacterial meningitis, accounting for 34 (21.3 percent). Of 11 neonates recorded, 7 (63.6 percent) belonged to this latter group. There were 48 (22.3 percent) cases of aseptic meningitis, 5 tuberculous and 2 cryptococcal. The overall mortality was 14.4 percent. The fatality rate in pneumococcal meningitis was 25.5 percent whereas in that caused by Haemophilus it was 2.7 percent. No deaths were recorded in the aseptic group. The gram stain was useful in 65 percent of cases of bacterial meningitis. One third of aseptic cases had 50 percent or more of neutrophils in the CSF. The highest CSF white cell count in aseptic and bacterial meningitis was 2,176 and 36,000 cells/mm3, respectively. The highest CSF protein level in bacterial and aseptic meningitis was 774 mg/100 ml and 150 mg/ml, respectively. Because of the high incidence of unusual pathogens, there is a need for a modified approach to initial antibiotic treatment bearing in mind the multiple antibiotic-resistant strains that are frequently encountered (AU)

Serum lipoproteins and susceptibility of men of Indian descent to coronary heart disease. The St James survey, Trinidad

Prevalence of coronory heart disease (CHD) and fasting serum lipoprotein concentration in ethnic groups of Port of Spain, Trinidad, were compared. In a total community survey of 1416 men aged 35-69 years, angina pectoris, a history of possible myocardial infarction, and major Q waves on the electrocardiogram were significantly more common in men of Indian descent than in other ethnic groups (relative risk about 3/1). Indians had significantly lower high-density-lipoprotein-cholesterol (HDLch) concentrations and significantly higher low-density-lipoprotein-cholesterol (LDLch) concentrations than other groups. After allowance for age and ethnic group, men with major Q waves or a history of possible myocardial infarction had a significantly greater ratio of LDLch/HDLch than men without either. Comparison of surveys in the Caribbean suggests that in this region CDH is prevalent only in communities in which a sizeable portion of men have an LDLch/HDLch ratio greater than 6 and an LDLch concentration above 5mmol/l (Summary)

Genetic factors in the susceptibility of biomphalaria glabrata for different strains of schistosoma mansoni

Biomphalaria glabrata selected for genetic differences in susceptibility to infection with a Puerto Rican strain of schistosoma mansoni were exposed to a miracidia of a strain of S. mansoni from St. Lucia. The St. Lucian strain was less effective than the Puerto Rican. Results suggested that in snails susceptibility to the St. Lucian strain were determined by a single gene, with insusceptibility dominant (AU)