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T Sih

Publications and source records attributed to T Sih.

10 recordsLinked to original sources
PubMed1999

Correlation between respiratory alterations and respiratory diseases due to urban pollution.

BACKGROUND: Air pollution is strongly correlated with allergic and infectious diseases. Chronicity of the stimulation and immaturity of the defense system make children prone to respiratory diseases. The aim of this study was to assess the adverse effects of urban levels of air pollution, correlating children's respiratory diseases and ultrastructural studies in rats, compared to controls in a clean area. METHODS: An epidemiological survey was conducted with 2000 school children (age range 7-14 years old), divided into two groups of 1000 children each: the Red group from São Paulo city (17,000,000 inhabitants) and the Green group from a rural area around the city of Tupã with no air pollution at all. A questionnaire was given to the children's parents in order to estimate history of respiratory diseases and predisposing factors. A total of 69 rats were housed for 6 months in the center of São Paulo, and ultrastructural studies of the epithelium of the airways were done and compared to 56 control animals in the rural area. RESULTS: The Red group of children had a statistically significant (P < 0.005) high prevalence of respiratory diseases such as rhinitis, sinusitis, and upper respiratory infections (URI). Rats exposed to air pollution developed ultrastructural ciliary alterations. CONCLUSION: The results obtained in the present investigation suggest that chronic exposure to urban levels of air pollution may cause respiratory diseases in children and ultrastructural ciliary alterations in the epithelium of the airways in rats, when compared to controls in a pollution-free rural area.

Adolescent↗
PubMed1995

Characterization of ear fluid isolates of Alloiococcus otitidis from patients with recurrent otitis media.

Nineteen isolates of Alloiococcus otitidis from ear fluid samples collected by tympanostomy from patients at four geographic locations were identified by phenotypic characterization and genetic relatedness. Initial growth of A. otitidis isolates occurred after 3 days at 37 degrees C on brain heart infusion (BHI) agar with 5% rabbit blood. Heavy growth occurred in BHI broth supplemented with 0.07% lecithin and 0.5% Tween 80 after 4 days of incubation. The isolates were gram-positive cocci that divided on an irregular plane and produced metabolic lactic acid, pyrrolidonyl arylamidase, and leucine aminopeptidase. These cocci grew sparsely in 6.5% NaCl-BHI broth, were asaccharolytic on both fermentative and oxidative bases, and were cytochrome negative by the iron-porphyrin test. The cellular fatty acid profile of A. otitidis was distinguished from those of related genera and characterized by major amounts ( > or = 14%) of 16:0, 18:2, 18:1 omega 9c, and 18:0 and smaller amounts of 14:0, 16:1 omega 7c, 17:0, and 18:1 omega 7c. Fifteen isolates demonstrated > 69% relatedness by DNA-DNA hybridization. Four isolates plus the original 15 were confirmed as A. otitidis by dot blot hybridization with a digoxigenin-labeled nucleotide probe specific for this species. The intergenic space between the genes coding for the 16S and 23S rRNAs of alloiococci was amplified by PCR, analyzed by restriction fragment length polymorphism, and determined to consist of three different genetic types. Although beta-lactamase negative, A. otitidis demonstrated intermediate levels of resistance to beta-lactams, including expanded-spectrum cephalosporins, and were resistant to trimethoprim-sulfamethoxazole and erythromycin.

Bacterial Typing Techniques↗
PubMed1994

Glycoprotein (GP) Ib beta is the critical subunit linking GP Ib alpha and GP IX in the GP Ib-IX complex. Analysis of partial complexes.

The glycoprotein (GP) Ib-IX complex is the receptor on platelet surfaces that mediates their adhesion to subendothelium. It comprises three polypeptides (GP Ib alpha, GP Ib beta, GP IX), each of which belongs to a superfamily of proteins containing conserved leucine-rich motifs. In this study, we used Chinese hamster ovary (CHO) cells expressing every combination of two GP Ib-IX complex subunits to demonstrate that GP Ib beta plays an essential role in the synthesis of the heterotrimer by associating with both of the other two subunits. Confocal microscopy demonstrated that GP Ib beta was present in the same cellular locations as GP Ib alpha in CHO alpha beta cells (cells expressing only GP Ib alpha and GP Ib beta) and as GP IX in CHO beta IX cells. The two polypeptides expressed in CHO alpha IX cells did not co-localize. Association between GP Ib alpha and GP Ib beta was demonstrated biochemically on immunoblots of detergent lysates of CHO alpha beta cells; electrophoresis under nonreducing conditions revealed the two subunits to be covalently linked through a disulfide bond. Association of GP Ib alpha and GP Ib beta was further demonstrated by the finding that immunoprecipitations with antibodies against either polypeptide precipitated both. Similarly, immunoprecipitations of lysates of CHO beta IX cells with antibodies against GP Ib beta or GP IX precipitated both polypeptides. In contrast, co-immunoprecipitation of the two polypeptides expressed in CHO alpha IX cells could not be demonstrated. Transient expression in CHO cells of GP Ib beta with GP IX yielded higher GP IX levels on the cell membrane than did expression of GP IX alone; supertransfection of CHO alpha IX cells with GP Ib beta also increased GP IX levels on the cell surface.

Amidohydrolases↗
PubMed1994

Association of GP Ib with actin-binding protein does not require GP IX.

GP IX is necessary for optimal expression of the GP Ib-IX complex on the surface of transfected cells, and presumably also on the surface of the platelet. The authors investigated whether increasing complex association with the cytoskeleton is one mechanism by which GP IX exerts its effect. CHO and L cell lines that express high levels of GP Ib were used to determine whether GP Ib (GPIb alpha and GPIb beta) associated with the cytoskeleton. GP Ib in these cells was found in the insoluble cytoskeletal fraction from Triton X-100 lysates in a proportion similar to that found in cells expressing the full complex. As in platelets and cells expressing the full complex, the association of GP Ib with the cytoskeleton was shown to be mediated by actin-binding protein (ABP). This was demonstrated by the observation that a monoclonal antibody against GPIb alpha precipitated ABP from GP Ib-expressing cells, and polyclonal anti-ABP antibodies specifically coprecipitated GP Ib. In addition, colocalization of the two components in intact cells was demonstrated by confocal microscopy. These data indicate that the association of GP Ib with the cytoskeleton is independent of GP IX, which therefore must increase surface expression of the complex by another mechanism.

Animals↗
PubMed1993

Prophylaxis for recurrent acute otitis media: a Brazilian study.

We enrolled 60 children with recurrent acute otitis media (AOM) in a study of the effectiveness of antimicrobial prophylaxis. All children were entered into the study following an acute episode of infection treated with amoxicillin (AMX) for 10 days. Following therapy, the children were re-examined, and then randomly assigned to receive either trimethoprim-sulfamethoxazole (TMP-SMX), amoxicillin (AMX) or a placebo (PLA). Twenty children were included in each group. Each drug was administered once a day at bedtime, at 1/3 the therapeutic dose, for 3 months. Children were re-evaluated with pneumootoscopy during episodes of acute illness and with pneumootoscopy and impedance tympanometry (TYMP) at monthly intervals. We observed a significantly increased rate of recurrent AOM in children receiving placebo compared with those who received antibiotics (50% vs. 17% P < 0.005). Both prophylactic antibiotics were equally effective in preventing recurrent AOM (recurrence rate 20% TMP-SMX, 15% AMX). We also observed that recurrences in children receiving placebo occurred earlier in the study period than in those receiving antibiotics. These results suggest that antimicrobial prophylaxis in children with recurrent acute otitis media is effective in reducing subsequent disease. The similar efficacy of both antibiotics tested suggests that the less expensive agent should be used.

Amoxicillin↗
PubMedDate not supplied

[Controversial drugs in otorhinolaryngology]

OBJECTIVES: To present a review on the most important groups of drugs used to treat otorhinolaryngological disorders. METHOD: Review of the literature about treatment of pediatric upper respiratory infections and allergy, using MEDLINE and LILACS data. RESULTS AND COMMENTS: Pediatric otorhinolaryngological disorders are extremely frequent and most of the time acute. They are one of the major reasons for pediatric visits. The therapeutical management of these conditions in many cases accounts for an over use of drugs, specially antibiotics, antipyretic and drugs of doubtful value, such as decongestants and expectorants. Judicious use, correct indication, and side effects of these drugs must be better known by physicians who deal with the child's health.

Journal Article↗
PubMedDate not supplied

[Diagnosis and therapeutic management of sinusitis in children]

OBJECTIVE: The authors review the main aspects related to the diagnosis and management of sinusitis in children, according to the medical literature. METHODS: Literature review. RESULTS: Clinical criteria, microbiology, image diagnosis, medical and surgical management are presented, whenever sinusitis is considered. CONCLUSIONS: The standardization of the clinical approach in children's sinusitis allows optimization of the diagnosis and the appropriate subsidiary exams, as well the correct use of antimicrobials and others drugs, or surgery in selected cases.

Journal Article↗