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Biomedical subjects

H Siregar

Publications and source records attributed to H Siregar.

At least 19 recordsLinked to original sources

Cholera in Indonesia in 1993-1999.

Cholera-specific surveillance in Indonesia was initiated to identify the introduction of the newly recognized Vibrio cholerae non-O1, O139 serotype. Findings from seven years (1993-1999) of surveillance efforts also yielded regional profiles of the importance of cholera in both epidemic and sporadic diarrheal disease occurrence throughout the archipelago. A two-fold surveillance strategy was pursued involving 1) outbreak investigations, and 2) hospital-based case recognition. Rectal swabs were transported to Jakarta for culture and isolates were characterized by serotypic identification. Outbreak findings showed that V. cholerae O1, Ogawa serotype, was the predominant etiology in all 17 instances of investigated epidemic transmission. Monitoring of eight hospitals representing seven provinces provided 6,882 specimens, of which 9% were culture positive for V. cholerae: 589 (9%) for O1 and 20 (< 1%) for non-O1 strains. Proportional representation of V. cholerae O1 among cases of sporadic diarrheal illness was variable, ranging from 13% in Jakarta to < 1% in Batam. Overall, 98% of V. cholerae O1 cases were the Ogawa serotype. There was no instance of non-O1, O139 serotype introduction in either epidemic or sporadic disease form. Anti-microbial drug susceptibility was consistently demonstrated, both temporally and spatially, except against colistin. Evidence is provided that epidemic and sporadic cholera occurrence in western Indonesia is associated with periods of low rainfall. Conversely, in the more eastern portion of the country, heavy rainfall may have contributed to epidemic cholera transmission.

Adolescent↗

HIV replication in chronically infected macrophages is not inhibited by the Tat inhibitors Ro-5-3335 and Ro-24-7429.

Human immunodeficiency virus infects different cell types including CD4+ lymphocytes and monocyte-derived macrophages (MDMs). We have examined the activity of the HIV-1 Tat inhibitors Ro-5-3335 and Ro-24-7429 in cultured human peripheral MDMs. Monocytes were isolated from HIV-seronegative donors by gradient centrifugation and plastic adherence. MDMs and unfractionated peripheral blood mononuclear cells (PBMCs) were infected with HIV Ba-L and then treated with drug either immediately (acute infection) or after 4 days (PBMCs) or 14 days (MDMs) (chronic infection). Inhibition of HIV replication by each drug was assessed by quantitation of HIV p24 antigen in culture supernatant using an enzyme immunoassay. In acutely infected MDMs, Ro-5-3335 (10 microM) and Ro-24-7429 (10 microM) resulted in 77% and 99% mean inhibition, respectively, of HIV replication with a clear dose response at lower concentrations; chronically infected MDMs were much less susceptible to these drugs, with both compounds inhibiting p24 antigen production by less than 50% at 10 microM. The drugs had no deleterious effect on cell viability at any concentration tested. In acutely infected PBMCs Ro-5-3335 and Ro-24-7429 resulted in 68% and 68.5% mean inhibition at 10 microM; when the compounds were added 4 days after infection inhibition was less than 50% compared with controls. Thus, the Tat inhibitors were effective in inhibiting acute HIV infection in MDMs but not in chronically infected cells, findings that differ from those of published studies using continuous lymphoblastoid cell lines.

Antigens, Viral↗

Common expression of the multidrug resistance marker P-glycoprotein in B-cell chronic lymphocytic leukaemia and correlation with in vitro drug resistance.

The expression of P-glycoprotein (Pgp), which is associated with multidrug resistance (MDR), was investigated in 20 B-cell chronic lymphocytic leukaemia (B-CLL) patients by flow cytometry using two Pgp-specific monoclonal antibodies (mAb), MRK-16 which recognizes an extracellular epitope, and JSB-1 which recognizes an intracellular epitope. Sixteen (80%) patients were positive with MRK-16 whereas all patients were positive with JSB-1. The proportion of Pgp-positive lymphocytes from each patient sample varied from 2-94% for MRK-16 and 20-93% for JSB-1. There was no correlation between the level of positivity and disease stage or treatment history. In vitro drug resistance to vincristine (VCR) and doxorubicin (DOX) was determined by the colorimetric MTT assay. All patients were resistant to one or both drugs being consistent with the expression of Pgp. There was no correlation between the level of resistance and disease stage or drug treatment. We investigated the expression of Pgp in the normal counterpart of the B-CLL cells, CD5+CD19+ B-lymphocytes. A minor subpopulation (3%) of CD5+CD19+ lymphocytes isolated from normal controls expressed Pgp suggesting that these cells may be the potential precursors to the B-CLL cell. We conclude that Pgp expression and drug resistance are inherent characteristics of the B-CLL lymphocyte.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

Relative contribution of fat, protein, carbohydrate, and ethanol to intestinal hyperemia.

The relative contribution of dietary fat, protein, carbohydrate, and ethanol to postprandial intestinal hyperemia was assessed by comparing the vascular and metabolic effects of luminal placement of various solutions prepared from standard high -fat, high-protein, and high-carbohydrate test diets, corn oil, and ethanol in the jejunum of anesthetized dogs. The high-fat diet (45% fat, 18% protein, 29% carbohydrate) produced the greatest hyperemia (+30.4% of control), followed by high-protein (22% fat, 64% protein, 4% carbohydrate) (+24.1%) and high-carbohydrate (8% fat, 18% protein, 68% carbohydrate) (+18.2%) diets. When the fat content of the high-carbohydrate diet was raised to equal that of the high-protein diet, the two diets produced the same degree of hyperemia. All three diets produced a significantly greater hyperemia than the solutions containing the same amount of fat. All these dietary solutions increased intestinal oxygen consumption. Ethanol, however, increased blood flow without altering oxygen consumption. Thus, on weight basis, fat produces the greatest hyperemia, but the contribution of protein and carbohydrate to postprandial intestinal hyperemia cannot be considered as insignificant. The hyperemia results from a synergistic effect of all three dietary components.

Animals↗

Role of histamine H1- and H2-receptors in postprandial intestinal hyperemia.

Studies were conducted in anesthetized dogs to assess whether histamine H1- and/or H2-receptors play a role in post-prandial intestinal hyperemia. The vascular and metabolic responses of jejunal segments to intra-arterial infusion of histamine and luminal placement of food before and after administration of tripelennamine, an H1-receptor antagonist, metiamide, an H2-receptor antagonist, and the combination of both antagonists were compared. Administration of the antagonists had no effect of jejunal blood flow and intestinal oxygen uptake (VO2). Tripelennamine or metiamide alone attenuated while the combination of both blocked the histamine-induced increases in blood flow and VO2. Metamide alone had no effect on the food-induced increases in flow and VO2. Tripelennamine significantly attenuated the food-induced increase in flow and blocked the increase in VO2. A 30% increase in flow was reduced to 15% after tripelennamine. The effects of tripelennamine plus metiamide were statistically the same as those of tripelennamine alone. It is concluded that endogenous histamines may play a role in postprandial intestinal hyperemia, and the effect is primarily mediated by the H1-receptors.

Animals↗

Ichthyosis fetalis.

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Adult↗

Congenital malformation among newborns at Dr. Pirngadi Hospital Medan during 1981-1984.

A study on the incidence of congenital malformation had been assessed among 15,185 newborns delivered in the Neonatal Unit, Dr. Pirngadi Hospital Medan during 1981-1984. Still-births were not included in this study. Out of these 15,185 newborns there were 77 cases (0.51%) of congenital malformation. The four leading malformations were pes-equinovarus 7 cases (9.1%), labiognathopalatoschizis, hydrocephalus and anencephalus 6 cases each (7.7%). The number of congenital malformations was higher in the age group of mothers older than 35 years (0.78%) and in the group of babies born in the birth order as third and further (53.85%) and as first born babies (33.33%). From 77 cases with congenital malformation only 2 (2.56%) were operated soon after birth, while 49 cases (64.1%) went home without surgical intervention, and 28 cases (35.9%) died during hospitalization.

Adult↗

Hemorrhagic varicella.

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Antineoplastic Agents↗