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Biomedical subjects

A W Chow

Publications and source records attributed to A W Chow.

At least 91 records · Page 5Linked to original sources
PubMed1986

Vancomycin-induced neutropenia.

A case of vancomycin-induced neutropenia is presented with a review of other reported cases in the literature. A 59-year-old white female was started on vancomycin therapy for a chronic infection of a total left hip replacement. After 38 days of treatment, the patient developed a severe leukopenia with a white blood cell count of 1700/mm3 and the presence of only occasional neutrophils. Upon discontinuation of vancomycin, the leukocyte and neutrophil counts promptly increased with full recovery in one week. Subsequently, the patient was restarted on a five-day course of vancomycin at a lower dose that proved uneventful with no recurrence of neutropenia. It is unclear whether the neutropenia would have recurred with a longer course of vancomycin. A review of the literature suggests that an immunologic mechanism may be responsible for the reaction. Physicians and other health professionals should be aware that neutropenia is a potential reaction of patients receiving prolonged vancomycin treatment.

Agranulocytosis↗
PubMed1985

A syndromic approach to common parasitic diseases.

Standard textbooks discuss parasitic disease according to specific organisms. In contrast, patients with parasitic infections present to physicians with a variety of clinical manifestations that may involve any of several organ systems and that often mimic nonparasitic diseases. A syndromic approach to the clinical situation may help the physician in considering the most important parasitic agents. Many parasitic infections can be acquired in temperate climates. While often considered tropical or exotic, other parasitic diseases are now seen more frequently in developed countries because of immigration and increased world travel. In this review the clinical syndromes associated with common parasitic diseases in North America are discussed, with an emphasis on risk factors and diagnosis of specific infections.

Cholangitis↗
PubMed1985

Quality of use of parenteral metronidazole therapy in a teaching hospital.

The recent release, relatively high cost and potential adverse effects of parenterally administered metronidazole prompted a quality-of-use audit at a 1000-bed teaching hospital. Ninety-two courses of treatment in 81 inpatients during a 6-week period were studied. Appropriateness of therapy was assessed on the basis of published indications. Parenterally administered metronidazole was prescribed primarily in anaerobic and anaerobic-aerobic infections. It was used as frequently for prophylaxis as for therapy. Surgical services accounted for 95% of the treatment courses. Inappropriate use was noted in 27 (29%) of the courses: agents other than parenterally administered metronidazole were indicated in 12 (13%), while the dose, dosing interval or duration of treatment was suboptimal in 15 (16%). Substantial savings would be achieved if oral or rectal metronidazole therapy were substituted for intravenous therapy for perioperative prophylaxis in elective colorectal surgery. Written justification for use and automatic stop orders are recommended to improve the cost effectiveness of both prophylactic and therapeutic use of selected antimicrobial agents.

Bacterial Infections↗
PubMed1985

Neurotoxic effects during vidarabine therapy for herpes zoster.

Two cases of neurotoxic effects resulting from therapy with vidarabine are described. Both patients were undergoing treatment for cutaneously disseminated herpes zoster complicating therapy for solid malignant tumours. Both had normal renal function. The serum levels of hepatic enzymes were normal in one patient and slightly elevated in the other. Neurotoxicity was first manifested in both patients by the development of intention tremors that progressed to gross tremors. Obtundation, coma and death ensued in one patient and pain syndromes in the other. Vidarabine-induced neurotoxic effects, which may occur in the absence of hepatic or renal dysfunction or treatment with another drug, may be mild initially but may progress rapidly to more serious, even life-threatening, conditions. Presentation of neurotoxic effects should be considered an indication for withdrawal of vidarabine.

Aged↗
PubMed1985

In vitro activity of Sch 34343 and cefbuperazone against anaerobic bacteria.

The in vitro activities of Sch 34343, a new penem antibiotic, and cefbuperazone, a new cephamycin antibiotic, were determined against 459 clinical anaerobic bacterial isolates and compared with the activities of imipenem and cefoxitin, respectively, by an agar dilution method. Both penems showed potent and similar activity against all anaerobic bacteria tested, particularly Peptococcus spp., Bacteroides fragilis, and Clostridium perfringens. All organisms except a single strain of Fusobacterium necrogenes were inhibited by an 8 micrograms/ml concentration of either Sch 34343 or imipenem. Overall, gram-positive bacilli, particularly Lactobacillus species, Clostridium difficile, and Bifidobacterium and Actinomyces species, were relatively more resistant to either penem than other genera of anaerobic bacteria tested. Cefbuperazone demonstrated only modest activity against a wide spectrum of anaerobic bacteria. It had excellent and selective activity against B. fragilis and Bacteroides vulgatus but was highly inactive against Bacteroides distasonis and Bacteroides thetaiotaomicron within the B. fragilis group. Both cephamycins showed virtually no activity against C. difficile and Lactobacillus spp. Although cefbuperazone was more active against Bifidobacterium spp., it had less activity against Fusobacterium spp., Eubacterium spp., and all Bacteroides spp. other than B. fragilis and B. vulgatus.

Anti-Bacterial Agents↗
PubMed1985

In vitro susceptibility of Clostridium difficile to new beta-lactam and quinolone antibiotics.

The in vitro susceptibilities of 34 to 73 clinical isolates of Clostridium difficile to 24 antimicrobial agents, including 18 beta-lactams, 4 fluoroquinolones, clindamycin, and metronidazole were examined. Metronidazole was the most active (MIC for 90% of the isolates [MIC90], 0.5 microgram/ml), followed by the carbapenems (Sch 34343, 4 micrograms/ml; imipenem, 8 micrograms/ml) and the antipseudomonas penicillins (piperacillin, 8 micrograms/ml; ticarcillin, 32 micrograms/ml; carbenicillin, 32 micrograms/ml). A monobactam (aztreonam) and most cephalosporins were either highly inactive (cefoxitin, cefuroxime, cefotiam, cefsulodin, ceftizoxime, cefbuperazone, and cefotaxime), with an MIC90 of greater than or equal to 128 micrograms/ml, or moderately inactive (ceftriaxone, cefmenoxime, cefoperazone, ceftazidime, and moxalactam), with an MIC90 of greater than or equal to 32 micrograms/ml. Clindamycin (MIC90, 32 micrograms/ml) and the fluoroquinolones (ciprofloxacin, 8 micrograms/ml; A-56619, 8 micrograms/ml; A-56620, 8 micrograms/ml; norfloxacin, 32 micrograms/ml) were only variably active. These in vitro data per se may not necessarily predict the relative risks for C. difficile-associated diarrhea or colitis during therapy with these agents. However, these data, in concert with knowledge of drug bioavailability in feces and the broad-spectrum antimicrobial activity on the resident bowel flora, may provide additional insight into the mechanisms and predictability of this complication with these agents. Careful monitoring for the emergence of C. difficile and fecal cytotoxin and for diarrhea during therapy with these agents is clearly indicated.

Anti-Bacterial Agents↗
PubMed1984

Variant postpartum toxic shock syndrome with probable intrapartum transmission to the neonate.

We report a unique mother-infant pair with variant staphylococcal toxic shock syndrome and probable intrapartum transmission to the neonate. Diagnosis of probable toxic shock was supported by the finding of fever, desquamative skin rash, multi-organ system involvement, and pronounced mucocutaneous manifestations, including strawberry tongue, dermal swelling, pharyngitis, and vulvar edema, although hypotension was absent. Staphylococcus aureus was isolated from the vagina, placenta, chorioamnion, and surface swabs and gastric aspirates of the infant. The isolates produced enterotoxin C but not enterotoxin F, and illness developed in both mother and infant despite preexisting high antibody titers to enterotoxin F and enterotoxin C. This unique mother-infant pair highlights our present lack of knowledge of the precise etiology and pathogenesis of toxic shock syndrome and illustrates the consequent difficulty in clinical diagnosis and laboratory confirmation of this disease in certain patients with atypical presentations.

Adult↗
PubMed1984

Toxic shock syndrome: clinical and laboratory findings in 30 patients.

Thirty patients with toxic shock syndrome (TSS) that developed between May 1980 and March 1983 in Vancouver were studied prospectively. In the 15 cases related to menstruation the illness followed a uniform and predictable clinical course. In the 15 other cases (3 in males) the disease was not related to menstruation, and the sources of the Staphylococcus aureus infections were diverse; 67% were hospital-acquired. Profound but transient lymphocytopenia associated with marked leukocytosis was the most striking laboratory finding and one not previously emphasized in the literature. S. aureus was isolated from sites of soft-tissue infection, the vagina or the endocervix in all except one case. Two patients had bacteremia. Phage types 29 and 29 + predominated among the isolates tested. All the genital S. aureus isolates tested produced the TSS marker protein, while the bacteria from wounds, throat, nose and blood were sometimes positive. Two patients (7%) died from refractory shock and multiple organ failure. All patients with a febrile, exanthematous, multisystem illness, particularly if it is associated with menstruation or a staphylococcal infection, should be evaluated promptly and treated empirically for TSS.

Adolescent↗
PubMed1984

Monoclonal antibodies as probes for unique antigens in secretory cells of mixed exocrine organs.

In the past, it has been difficult to identify the secretory product and control mechanisms associated with individual cell types making up mixed exocrine organs. This report establishes the feasibility of using immunological methods to characterize both the biochemical constituents and regulatory mechanisms associated with secretory cells in the trachea. Monoclonal antibodies directed against components of tracheal mucus were produced by immunizing mice with dialyzed, desiccated secretions harvested from tracheal organ culture. An immunofluorescence assay revealed that of the total 337 hybridomas screened, 100 produced antibodies recognizing goblet cell granules; 64, gland cell granules; and 3, antigen confined to the ciliated apical surface of the epithelium. The tracheal goblet cell antibody described in this report was strongly cross-reactive with intestinal goblet cells, as well as with a subpopulation of submandibular gland cells, but not with cells of Brunner's glands or the ciliated cell apical membrane. The serous cell antibody was not cross-reactive with goblet, Brunner's gland, or submandibular cells, or the ciliated cell apical membrane. The antibody directed against the apical membrane of ciliated cells did not cross-react with gland or goblet cells or the apical membrane of epithelial cells in the duodenum. Monoclonal antibodies, therefore, represent probes by which products unique to specific cells or parts of cells in the trachea can be distinguished. The antibodies, when used in enzyme immunoassays, can be used to quantitatively monitor secretion by individual cell types under a variety of physiological and pathological conditions. They also provide the means for purification and characterization of cell-specific products by immunoaffinity chromatography.

Animals↗
PubMed1984

Vaginal colonization with Staphylococcus aureus, positive for toxic-shock marker protein, and Escherichia coli in healthy women.

The vaginal colonization of 495 healthy women with strains of Staphylococcus aureus positive for the toxic-shock marker protein (pyrogenic exotoxic C) was examined prospectively. Production of the marker protein was detected by analytic isoelectrofocusing of culture filtrates in polyacrylamide gels (isoelectric point, 7.2). Toxicogenic strains of S. aureus were isolated from 2.6% of the women and nontoxicogenic strains from 4.0%. Vaginal carriage of toxicogenic S. aureus was found to be significantly correlated only with coisolation of Escherichia coli when a number of factors were analyzed by multivariate logistic regression and compared with values among women carrying no vaginal S. aureus or only nontoxicogenic strains (odds ratios, 8.17 and 11.02, respectively; 95% confidence intervals, 2.27-29.31 and 1.42-85.31, respectively). These data may explain the higher rate of vaginal colonization with E. coli in addition to toxicogenic S. aureus among women with toxic-shock syndrome (64%) than among age-matched control women (12%; P less than .001).

Adult↗
PubMed1984

Quantitative vaginal microflora in women convalescent from toxic shock syndrome and in healthy controls.

We performed sequential and quantitative vaginal cultures obtained from 8 women within 4 days to 3 years (average, 15.8 months) after their recovery from classic menstrual toxic shock syndrome (TSS) and from 11 healthy women who served as age-matched controls. Apart from tampon use, which was significantly less frequent in TSS women after their acute illness, no demographic differences were observed in the two groups. Significantly lower total aerobic and anaerobic bacterial counts were found in TSS women than in healthy controls (P less than 0.05, Mann-Whitney test). These differences were most profound during the menstrual (aerobes) and premenstrual (aerobes and anaerobes) sample times, whereas no difference in bacterial counts was observed in the mid-cycle samples. Although the less frequent usage of tampons among TSS women after their acute illness might explain the lower aerobic counts in menstrual specimens, this is unlikely to explain the significantly lower aerobic and anaerobic counts observed in premenstrual samples when tampons were not used in either group. It is possible that these differences in the quantitative vaginal microflora were a direct result of recent TSS in these women. Alternatively, disruption of the normal indigenous microflora could have predisposed these women to acute TSS by alteration of the resistance of vaginal colonization to pathogenic microorganisms.

Contraceptive Agents, Female↗
PubMed1984

A two-dimensional immunoelectrophoretic analysis of the heat-shock response exhibited by Neurospora crassa cells.

The heat-shock (HS) response of Neurospora crassa was studied by two-dimensional (2-D) immunoelectrophoresis, in conjunction with in vivo labelling of proteins with [35S]methionine. Antisera against extracts of normally grown and shocked cells were tested with both extracts as antigens. The resolution of normal cell proteins by interaction with homologous antisera yielded at least 35 immunoprecipitates. Using antisera to shocked cells with normal and shocked cell extracts resolved four heat-shock proteins (nhsps): new polypeptides synthesized upon HS and those with an enhanced production. Extracts of partially recovered cells showed proteins typical of normal cells, as well as those specific to the shocked state. Immunogenicity of some proteins appeared altered after heat shock. Following adsorption of HS cell extracts by normal antisera, three unique proteins were recognized in shocked cell extracts, along with a fourth displaying a markedly enhanced level. Stained bands corresponding to two abundant hsps (relative mass 68 000 and 81 000 daltons; referred to as nhsp 70 and nhsp 80) were excised from slab gels and the eluted proteins were employed as immunogens in rabbits. The resulting antibodies were used to identify corresponding proteins in autoradiographs of 2-D immunoelectrophoretograms.

Heat-Shock Proteins↗
PubMed1983

Drug resistance in malaria: three cases and a review.

Drug resistance has been well documented in two species of malarial parasites. Of greatest concern are the rapid developments in the resistance of Plasmodium falciparum to commonly used therapeutic and chemoprophylactic agents. This species, which is capable of producing life-threatening disease, has shown various levels of resistance in different parts of the world. Also, some strains of the most common species causing relapsing disease, P. vivax, exhibit resistance to primaquine. Three cases of malaria that demonstrate various types of drug resistance are presented in this paper.

Adult↗
PubMed1983

Empyema caused by Clostridium perfringens.

Trauma, chest surgery or other invasive procedures and underlying lung disease are often found to precede clostridial empyema. A case is described in which empyema caused by Clostridium perfringens was not associated with any of these factors.

Adult↗
PubMed1983

Auditing antibiotic use in a teaching hospital: focus on cefoxitin.

The prevalence and nature of antibiotic misuse in a major teaching hospital was assessed by means of a quality-of-use audit. Cefoxitin was chosen for study. The use of cefoxitin increased rapidly during the study period, accounting for 17.7% ($15300) of the pharmacy's costs for cephalosporins during the first year of its availability but 47.7% ($60707) during the second year. Cefoxitin was inappropriately used for 43% of the patients receiving it during the first 2-month audit period and for 25% of those receiving it during the second audit period, 1 year later (p less than 0.01 by chi-square analysis).

Anti-Bacterial Agents↗
PubMed1983

Vaginal colonization of Escherichia coli and its relation to contraceptive methods.

The prevalence rate of vaginal colonization with E. coli was studied prospectively among 495 healthy premenopausal women, and factors associated with vaginal carriage of E. coli were examined. Vaginal colonization with E. coli was found in 12% of women, and was significantly correlated with phase of the menstrual cycle (p less than 0.05), prior use of antibiotics (p less than 0.05), current genital complaints (p less than 0.05), history of previous urinary tract infection (p less than 0.001), and use of diaphragm or cervical cap for contraception (p less than 0.005). The high prevalence rate among diaphragm or cervical cap users remained significant when other confounding factors were kept constant (p less than 0.05). This observation may explain the association of diaphragm use and urinary tract infection demonstrated in previous epidemiologic studies and confirmed in the present study (p less than 0.05).

Adult↗
PubMed1983

Leukotriene-C4 enhances mucus production from submucosal glands in canine trachea in vivo.

Because leukotrienes have been implicated as putative mediators in upper airways disease, we studied whether leukotriene C4 (LTC4) might also have a mucus enhancing effect on submucosal glands. We anesthetized mongrel dogs with chloralose (100 mg/kg) and urethane (500 mg/kg) and ventilated them on a pump. To help visualize the secretions from submucosal glands, we exposed the mucosa of the upper trachea and coated its surface with powdered tantalum. Secretions from the glands (hillocks) were measured with time: The number of hillocks was measured at four time points on 19 dogs after each treatment in the sequence: no LTC4, LTC4, no LTC4 and LTC4 + blocker. The potential blockers were nerve cutting, atropine, FPL-55,712, and hexamethonium. Each potential blocker was used on 3-5 dogs. LTC4 was injected into the cranial thyroid artery. In 19 dogs with 27 responses, LTC4(8.6-11.0 micrograms) gave a positive response that was significantly different from control (P less than 0.01) at 1-4 min. These effects were not abolished in 5 dogs by cutting the superior laryngeal (SLN) and the vagus nerves (P less than 0.01). Pretreatment of the dogs (n = 5) with atropine, hexamethonium and the specific SRS-A (LTC4) antagonist FPL 55,712 (n = 3) gave a statistically significant (P less than 0.01-0.05) reduction in mucus secretion at all times for atropine, hexamethonium, and at all times except 4 min for (FPL 55,712). These results indicate that leukotriene C4 induces mucus secretion in dogs. This secretion does not depend on an intact reflex pathway but is altered at the individual gland by agents which block ganglionic motor pathways.

Animals↗