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Biomedical subjects

J S Tan

Publications and source records attributed to J S Tan.

At least 19 recordsLinked to original sources

[Therapy of cantharides extract for perennial allergic rhinitis and its effect on total IgE in serum].

The therapy of 10% Cantharides extract in treating 50 cases of perennial allergic rhinitis (PAR) was studied. The extract was plastered and blistered on Dazhui, Neiguan point. It was observed by nasal mucosa provocative test, cells in nasal secretion test and serum total IgE test. The results showed that its effective rate was 88%, the allergic nasal mucosa provocative test of treated group alleviated obviously after the treatment (P < 0.01), the number of eosinophil and basophil in nasal secretion decreased (P < 0.01, P < 0.05); and the serum total IgE also reduced significantly (P < 0.01).

Acupuncture Points

Efficacy and safety of piperacillin/tazobactam in skin and soft tissue infections.

Piperacillin/tazobactam has excellent in vitro activity against the most pathogens involved in skin infections. Two large multicentre studies recently evaluated the efficacy and safety of piperacillin/tazobactam in the treatment of skin and soft tissue infections in patients in hospital. The efficacy and safety of piperacillin/tazobactam (4 g/500 mg every 8 hours) have been assessed in an open study in Europe. Among 120 evaluable patients, 93% were clinically cured or improved. Only six patients were withdrawn from the study because of side effects. In another trial, piperacillin/tazobactam were compared with ticarcillin/clavulanate in a double-blinded prospective study in the United States. Of evaluable patients, 67 received piperacillin/tazobactam (3 g/375 mg every 6 hours) and 44 received ticarcillin/clavulanate (3 g/100 mg every 6 hours). At assessment, 76% of patients given piperacillin/tazobactam and 77% of patients given ticarcillin/clavulanate had responded favourably. The lower success rate in this trial may be attributed to more stringent inclusion criteria that resulted in the incorporation of a higher proportion of patients with more severe conditions including diabetic/ischaemic foot infections. The incidence of adverse reactions was similar in both groups. Piperacillin/tazobactam seems to be both effective and safe in the treatment of skin and soft tissue infections in patients confined to hospital.

Bacterial Infections

Community-acquired pneumonia. The changing picture.

Important changes in the initial management of community-acquired pneumonia have been prompted by the discovery of new respiratory pathogens, the changing susceptibility of traditional pathogens to antimicrobial agents, and the introduction of new antimicrobial agents. Although the clinical presentation may suggest a specific pathogen, findings overlap too much to reliably distinguish the specific cause of the pneumonia on a clinical basis. Useful laboratory studies include Gram's stain and culture of sputum, blood culture, serologic studies, and new tests such as the urinary antigen test for Legionella pneumophila. Empirical antimicrobial treatment must take into consideration that 20% to 30% of cases of community-acquired pneumonia are due to atypical pathogens that are not susceptible to beta-lactam agents.

Anti-Bacterial Agents

Pharmacokinetics of imipenem in serum and skin window fluid in healthy adults after intramuscular or intravenous administration.

The pharmacokinetic profiles of imipenem after intramuscular (i.m.) and intravenous injections were examined in adult volunteers. Levels of imipenem in serum after i.m. injection of a microcrystalline suspension of imipenem-cilastatin (500 mg each) reached a peak (8.0 micrograms/ml) at 1.5 h after administration, and concentrations were maintained in excess of 1.5 micrograms/ml for 6 h. Serum elimination half-life (1.3 h), volume of distribution (14.5 liters), and area under the curve (AUC; 27.8 micrograms.h/ml) after i.m. injection did not significantly differ from those of a comparable dose given by intravenous infusion. Bioavailability after i.m. injection was 89%. Imipenem levels in skin window fluid after i.m. administration were maximal (4.3 micrograms/ml) at 4 h after injection, at which time imipenem concentrations exceeded those produced by intravenous infusion. The AUCskin window/AUCserum ratio for skin window fluid after i.m. injection was 68%, indicating good penetration of the drug into skin fluid. This study shows that i.m. injection of 500 mg of imipenem-cilastatin results in concentrations of imipenem in serum and skin fluid that are, for at least 6 h, consistent with antimicrobial activity against susceptible organisms.

Adult

Treatment of bacteriuria in pregnancy.

The presence of bacteriuria during gestation increases the chance of acute pyelonephritis. Treatment of bacteriuria in pregnancy reduces subsequent development of symptomatic disease. Numerous studies have shown that single-dose therapy for asymptomatic bacteriuria is as effective as longer course of treatment. Single-dose therapy also has the advantages of improved compliance, reduced costs, and less adverse effects resulting from long term therapy. Follow-up cultures following antimicrobial treatment should be used for early detection of recurrence or relapse. If the urine culture yields no growth, a urine culture at a monthly interval will suffice. If on the other hand bacteriuria is present, a repeat course of antimicrobial therapy should be chosen based on antimicrobial susceptibility testing. A longer course of therapy, possibly with a different drug, is recommended for women with a positive follow-up urine culture. Acute cystitis may be treated with the same regimen as asymptomatic bacteriuria. When upper urinary tract infection is suspected, hospitalisation and a longer course of therapy is recommended. If the organism is susceptible to cefalexin or nitrofurantoin, postcoital prophylaxis with either agent for the remainder of the pregnancy may be beneficial.

Anti-Infective Agents

Results of total hip replacement in renal transplant recipients.

A vascular necrosis of the femoral head associated with steroid immunosuppression is a cause of significant morbidity in renal transplant recipients. We review the results of 30 total hip replacements in 20 renal transplant recipients with a mean follow-up of 6.3 years. The mean age at the time of surgery was 35 years. The average Hospital for Special Surgery Hip Score was 17 points before operation and 32 points after operation. Fourteen hips were rated excellent and 12 hips rated good. There were four failures--one hip was revised for symptomatic loosening and three prosthesis were removed for infection. Twenty-seven of the hip replacements were subjectively rated as satisfactory by the patient. There was no significant difference in post-operative hip scores between cemented and uncemented prostheses. Total hip replacement in renal transplant recipients in this study has shown good long term result with a revision rate of about 3%. Late infection was a major problem with an incidence of 13%. Prophylactic antibiotics must be used whenever there is a risk of haematogenous seeding from transient bacteremia in these immunosuppressed patients. Use of uncemented prosthesis may make future revision arthroplasty easier.

Adolescent

Ambulatory management of lower respiratory tract infections.

Clinical manifestations and radiographic findings are unreliable guides to the selection of antimicrobial therapy for lower respiratory infections. Laboratory evaluation is necessary to identify the etiologic agent. Multiple oral antibiotics are available for outpatient treatment of bronchitis or pneumonia suspected to be of bacterial origin.

Anti-Bacterial Agents

Treatment of bacterial skin and soft tissue infections.

Bacterial skin infections occur commonly and range in severity from mild to life threatening. The severity of skin infections, and their management and prognosis, can depend on the mechanism of infection, the skin structures involved and the infecting organism or organisms. Primary skin infections result from invasion of microorganisms through tiny breaks in the epidermis or from the spread of microorganisms through the bloodstream. Secondary infections arise from pre-existing trauma, burns or surgical wounds; infections involving the soft tissues underlying the skin are also discussed. These also frequently occur in areas of trauma, operation or ischemia. The cause, bacteriologic factors and management of skin infections were studied, with special attention to pyodermas, infections of the foot in diabetic patients and necrotizing soft tissue infections. Choice of appropriate antibiotic agents depends in large part on the infecting organism and patterns of antibiotic susceptibility. In necrotizing soft tissue infections, survival or limb salvage may depend on prompt surgical intervention. In these instances and in some of advanced primary skin infections in which bacteremia is involved, parenteral antibiotics are required. The available options are discussed and a report on the data with the combination agent ticarcillin disodium and clavulanate potassium is presented.

Anti-Bacterial Agents

Effect of vacuum mixing on the mechanical properties of antibiotic-impregnated polymethylmethacrylate bone cement.

Polymethylmethacrylate bone cement, containing either no added antibiotic, 0.5 g of Vancomycin, 1.0 g of Vancomycin, or 1.0 g of Tobramycin, was mixed either in air or a vacuum chamber. Following storage in a water bath at 37 degrees C for 48 h, the specimens were tested in four-point bending. The porosity of the specimens was assessed radiographically, and their antibacterial activity was monitored for 21 days. The bending strength of the vacuum mixed specimens containing no antibiotic was 40% greater than that of similar air-mixed specimens. However, there were no significant differences in the bending strength of either the air- or vacuum-mixed specimens when any of the antibiotic dosages were added. The bending modulus of the vacuum-mixed specimens, containing no antibiotic, was significantly greater than the moduli of all the other specimen groups which did not differ from each other. Vacuum mixing reduced the apparent porosity of the specimens fivefold, and while the addition of antibiotic did not effect porosity of the air-mixed specimens, that of the vacuum-mixed specimens was doubled. Although initial rapid decreases were seen, leaching of antibiotic from the cement and antibacterial activity continued through the 21-day monitoring period.

Biomechanical Phenomena

Urinary tract infections in obstetrics and gynecology.

Escherichia coli is still the most common bacterial pathogen associated with urinary tract infections in women. Because of increasing resistance, ampicillin or a sulfonamide alone is no longer recommended for the empiric treatment of those infections. Antimicrobial therapy that contains a beta-lactamase inhibitor or that is resistant to the action of beta-lactamase is preferred. For the treatment of acute, uncomplicated lower urinary tract infection in a young woman, a short course of therapy (single dose) may be adequate. For an upper tract or complicated infection a longer course of therapy is advised. Asymptomatic bacteriuria in pregnancy should be treated; a short course of therapy with a beta-lactam antibiotic may be tried only if posttherapy follow-up cultures are planned. When bacteriuria persists or recurs, a longer course of therapy should follow, with consideration given to a urologic workup after delivery.

Anti-Bacterial Agents

Infections due to Corynebacterium group D2. Report of a case.

Corynebacterium group D2 is a gram-positive bacillus easily identified in clinical microbiology laboratories. However, this organism is often disregarded as a skin and mucous contaminant. The Spanish literature has recently described Corynebacterium group D2 as a urinary pathogen in a specific patient population. We report a case of Corynebacterium group D2 infection to illustrate the potential pathogenicity and clinical presentation of infection due to this organism in the United States.

Aged

Pharmacokinetics of intravenous cefmetazole with emphasis on comparison between predicted theoretical levels in tissue and actual skin window fluid levels.

Cefmetazole is a cephamycin antibiotic which is resistant to hydrolysis by various beta-lactamases. This study evaluated the pharmacokinetics of cefmetazole, including its intravascular and interstitial fluid distribution, by using the skin window (SW) technique. A 2-g dose of cefmetazole was given intravenously over 30 min to each of 12 healthy adult male volunteers every 6 h for nine doses. Plasma levels were assayed at predetermined intervals after doses 1, 5, and 9. Interstitial fluid levels were determined by the SW technique. Antibiotic levels were assayed by the agar well bioassay technique. A concentration-versus-time plot indicates that cefmetazole is rapidly distributed, with mean peak levels in plasma equal to 126 micrograms/ml at the end of the half-hour infusion. The mean plasma half-life was 1.1 h. Plasma and tissue distribution constants permitted calculation of theoretical levels in tissue. Parallel elimination slopes for SW and theoretical tissue level showed that the SW model distribution kinetics are closely related. The area under the curve for the SW was 73.9 mg.h/liter. This was comparable to the theoretical level in tissue, which was 96 mg.h/liter. Furthermore, the area under the curve of theoretical tissue level/plasma was 0.6 and that of SW/plasma was 0.47. These results demonstrate that the SW technique yielded a result quite close to the theoretical tissue level. Ultrafiltration analysis indicated that as cefmetazole levels in plasma increased from 10 to 250 micrograms/ml, plasma protein binding of the antibiotic dropped from 85 to 65%. Finally, 60 to 70% of the drug was recovered from the urine as biologically active drug over 6 h postinfusion.

Adult

Diagnosis and treatment of staphylococcal diseases.

Staphylococcus is, by far, the most commonly seen organism in podiatric infections. Although common, staphylococcal infections are difficult to understand and treat. These bacteria have undergone significant changes in their pathogenicity and antibiotic susceptibility over the last few years. Methicillin-resistant strains, once relatively rare, are becoming a major therapeutic dilemma in some centers.

Anti-Bacterial Agents

[Pathological study of bronchio-alveolitis induced by xinkang short-fiber chrysotile asbestos in rats].

Eighty-four rats were exposed intratracheally to 25 mg of locally produced Xinkang short-fiber chrysotile asbestos (98% of the fibers are less than 5 microns in length). In 1 to 3 d after instillation, the pathological changes in rat lungs demonstrated that the affection was mainly acute bronchio-alveolitis characterized by acute inflammatory exudation and injuries of the small airways and alveolar structural units. The four main manifestations of alveolitis induced by the chrysotile asbestos were of the neutrophilic, serous, alveolar macrophages and granulomatous varieties. Three types of pulmonary fibrosis developed gradually from 7 to 90 d following the exposure to the asbestos, i.e. the intraluminal, murally incorporated, and interstitial fibrosis. Findings showed the complete process from the acute inflammatory exudation and the damage to lung tissue, with the following repair and proliferation of injuried lung tissue and organization of exudate, to the final fibrosis and destruction of the lung. The results suggested that the persistent and irreversible damage to the epithelial cells of respiratory bronchioles and pneumocytes, and denudation and destruction of the basement membrane played an important role in the development of pulmonary fibrosis by forming a channel for the inflammatory exudates and fibroblasts migrating into the bronchioalveolar spaces. Therefore, the experimental results have proved that Xinkang chrysotile asbestos fibers less than 5 microns in length certainly have a fibrogenic effect.

Animals

Unsuspected pulmonary tuberculosis in a community teaching hospital.

Tuberculosis remains a significant clinical and public health problem in the United States. To determine if a significant proportion of hospitalized patients diagnosed as having pulmonary tuberculosis were not suspected of the disease following initial patient assessment, we retrospectively reviewed the microbiology records of a 515-bed community teaching hospital and identified all patients with culture-proven Mycobacterium tuberculosis infection hospitalized between January 1983 and December 1987. Pulmonary tuberculosis was not suspected in 13 (42%) of 31 patients with active disease. These patients were elderly (92% aged 65 years or older vs 8% aged less than 65 years), had a delay in respiratory isolation (6 vs 1 days) and diagnosis (8 vs 3 days), in addition to a longer hospitalization (16 vs 11 days) with increased mortality (46% vs 11%). Inadequate diagnosis may contribute to the persistence of morbidity and mortality from tuberculosis in this country.

Adult

Urinary tract infections in the elderly.

Urinary tract infection (UTI) is common in the elderly, with a prevalence of approximately 20% in women over 65 years of age. The elderly are predisposed to UTI by anatomic changes in the genitourinary system, by underlying disease, by instrumentation, and by residing in long-term care settings. Indwelling urinary catheters are a frequent cause of UTI, and catheter-associated sepsis is the most common cause of gram-negative sepsis in hospitals. Resistant organisms, prevalent in long-term care settings and hospitals, are increasingly responsible for UTI. Empiric antibiotic therapy has changed with the availability of new agents that cover resistant organisms. Oral antibiotics are appropriate for most UTIs; however, more serious infections require parenteral therapy. Length of antibiotic therapy is generally increased for UTI in the elderly.

Aged