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Biomedical subjects

T A Nguyen

Publications and source records attributed to T A Nguyen.

27 records · Page 2Linked to original sources
PubMed1997

Impaired resistance to the development of toxoplasmic encephalitis in interleukin-6-deficient mice.

The role of interleukin-6 (IL-6) in the pathogenesis of toxoplasmic encephalitis (TE) was examined by using IL-6-targeted mutant (IL-6(-/-)) mice. At 4 and 8 weeks after infection with the ME49 strain of Toxoplasma gondii, significantly greater numbers of T. gondii cysts and areas of inflammation associated with tachyzoites were observed in brains of IL-6(-/-) mice than in those of control mice. Large areas of necrosis were observed only in brains of IL-6(-/-) mice. Tachyzoites were frequently detected in the areas of necrosis, suggesting that necrosis was caused by proliferation of the parasite. These results indicate that IL-6 is protective against development of TE by preventing formation of T. gondii cysts and proliferation of tachyzoites in brains of infected mice. Whereas in brains of control mice, large numbers of inflammatory cells were always observed in areas where tachyzoites were detected, in brains of IL-6(-/-) mice, only small numbers of inflammatory cells were observed in many areas with tachyzoites. Lymphocyte preparations isolated from brains of infected control mice had significantly higher ratios of gamma/delta T cells and CD4+ alpha/beta T cells but lower ratios of CD8+ alpha/beta T cells compared to those of infected IL-6(-/-) mice. There were no differences in the ratios of these T-cell subsets in spleens between these mice. The amounts of mRNA for gamma interferon (IFN-gamma) detected by reverse transcriptase PCR were significantly smaller in brains of IL-6(-/-) mice than in those of control mice, whereas amounts of IL-10 mRNA were greater in the former than in the latter. IL-6 mRNA was detected only in infected control mice. The protective activity of IL-6 against development of TE appears to be through its ability to stimulate IFN-gamma production and induce infiltration and accumulation of different T-cell subsets in brains of infected mice.

Animals↗
PubMed1997

Reproductive understanding, sexual functioning and testosterone levels in men with spina bifida.

PURPOSE: We assessed the sexual functioning and understanding in men with myelodysplasia. MATERIALS AND METHODS: Of the 378 patients with myelodysplasia followed at our multidisciplinary clinic 170 are adults, including 58 men older than 18 years. A total of 57 men was available for interview. A questionnaire was administered to determine patient educational level, sexual understanding, sexual function and marital status, and serum testosterone levels were measured. RESULTS: The majority of the patients learned about sexual reproduction from school classes with 48 (84%) having achieved a twelfth grade education or higher. A total of 41 patients (72%) accurately described the basic concepts of reproductive physiology. Penile erections were experienced by 41 men (72%) including 27 (66%) who ejaculated with erection. Three patients ejaculated without erection. Sexual intercourse was attempted by 20 men (35%). Of the 11 patients (19%) who attempted to father children 8 (14%) were successful. Twelve patients (21%) have been married, including 2 who are divorced. Serum testosterone levels in 44 patients were normally distributed. CONCLUSIONS: Sexual reproductive understanding, and erectile and ejaculatory function are present in many men with myelodysplasia. The level of the neurological lesion was not predictive of erectile or ejaculatory function but it appears that reproductive potential is favored by lower and less severe lesions. All but 1 of the 8 patients who fathered children had an L5 or sacral neurological level lesion, each was ambulatory and none had a ventriculoperitoneal shunt at the time of conception. These data may prove useful when counseling patients and their parents about eventual sexual performance.

Adolescent↗
PubMed1993

[Typhoid fever in South Vietnam, 1990-1993].

In South Viet-nam, typhoid fever remains a considerable intestinal infection. Between 1990 and 1993, among 15 districts in the South of the country, a total per year of 3,853 to 9,179 cases was registered: from 8 to 31 led to death. Recently a large epidemic of typhoid fever broke out in the An Minh district (territory of KiênGiang, South Viet-nam), affecting 3,049 people and bringing on two cases of death. Among the 574 blood samples, 266 strains of S. Typhi, 22 S. Paratyphi A and 2 S. Choleraesuis have been isolated. Our investigations on the spot led to some epidemiologic and clinical reflexions and enabled us to estimate the effectiveness of quinolones (?) in the treatment for typhoid fever. The epidemic may be ascribed to different causes: lack of pure water supply in rural area; fecal pollution caused by inhabitants of this endemic area defecating directly in the waterways; ingestion of contaminated food, especially vegetables sprayed with polluted water; quite low level of public sanitation and individual hygiene. Clinically, the disease consists in prolonged fever, with digestive disorders (anorexia, diarrhoeae, diffuse abdominal aches). Splenomegalia and hepatomegalia are inconstant. The dissociation of the pulse from the temperature is not frequent and the rosy spots are rare. The antibiogramm applied on the isolated strains of S. Typhi revealed their resistance (R) to usual antibiotics (chloramphenicol, ampicillin, Bactrim), but S. Typhi is very sensitive to quinolones (ofloxacin, fléroxacin, R = 0).(ABSTRACT TRUNCATED AT 250 WORDS)

Drug Resistance, Microbial↗
PubMed1993

[Malaria in Vietnam. Environment, prevention and treatment].

In Viet-nam, malaria rages in mountainous and wooded areas, as well as in coastal areas. In these geographical zones, the diversified features of environment have different repercussions on the development of Anopheles species. The main vector species have strict oecological requirements: An. dirus, disseminated in the forests, colonizes stagnant and shaded water, such as rain water collected in ground dips and in cavities of trees and rocks; An. minimus selects its breeding-sites in pure and slightly current streamlets, in the hilly areas. On the contrary, An. sundaicus, first-rate coastal vector, adjusts itself to diversified biotopes, which nevertheless all have common features: saltiness of water (optimum 1-7 g NaCl/litre), faint sunning, stagnant or slightly current water, with floating green algae (Ceratophyllum, Najas). P. falciparum prevails in the wooded areas (P. f.: 75%; P. v.: 25%); but in the coastal areas where Anopheles hyrcanus pullulates, P. vivax reaches the same ratios as P. falciparum. In Viet-nam, the prevention and antimalarial fight are centred on three measures: diagnosis, treatment and watching of diseases, antivectorial fight, antimalarial fight combined with first medical care. Owing to the spreading of P. falciparum chemoresistance to chloroquine (27 to 76%) and to Fansidar (22 to 83%), we had to have recourse to new antimalarials: artemisinine and artesunate tested in several regions of the country (tests in vitro and in vivo during 28 days) revealed their high schizonticidal capacity, but the recrudescence reached 30 to 50%.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

[Giant cystadenocarcinoma of pancreatic origin and supra-mesocolic topography].

The authors report a case of pancreatic cystadenocarcinoma developed within a few days as a voluminous cyst of the left hypochondriac region, pushing away the organs of the supramesocolic zone. The tumor removal is easily performed because it was surrounded by a fibrotic capsule and their was no precise attach to the neighbouring organs. Diagnosis is carried out by microscopic examination revealing a tubulo-papillary cystadenocarcinoma of the pancreas. Quasi synchronous apparition of disseminated hepatic metastases advocates for heavy malignancy and justifies intrahepatic chemotherapy.

Antigens, Tumor-Associated, Carbohydrate↗
PubMed1981

An electrogenic component of resting potential in rabbit ventricular muscle?

The resting potential and the intracellular Na and K concentrations (Nai, Ki) were determined at several extracellular K concentrations (Ko) between 0.5 and 18 mM and after inhibition of the sodium pump with 0.5 microM ouabain. Exposure to low Ko (0.5 mM) produced a transient hyperpolarization (from -80 to -100 mV) followed by a depolarization that led to a stable potential of -60 mV within 25 min. Similar potential levels were observed in the presence of ouabain regardless of the Ko/Ki ratio. Intracellular sodium increased at Ko < 5 mM, whereas Ki rose at Ko less than or equal to 1.0 mM. Because of the large decrease of Ki at Ko = 0.5 mM, Ko/Ki was the same at 0.5 and 1 mM. However, the resting potentials at the steady state differed by 50 mV at these concentrations. A PNa/PK of 0.032 for the control conditions was obtained with the Mullins-Noda equation using 2.5 as the Na-K coupling ratio. This PNa/PK value yielded a Goldman potential of -69 mV; so we estimated that electrogenic sodium extrusion contributed -10 mV to the resting potential. The size of the electrogenic potential increased as Ko was lowered from 5 to 1 mM. This finding suggests that the control of the Na-K coupling ratio may be independent of the mechanism that controls the pumping rate.

Animals↗