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Biomedical subjects

K Weiss

Publications and source records attributed to K Weiss.

At least 73 records · Page 4Linked to original sources
PubMed1997

Asystole during dipyridamole infusion in patients without coronary artery disease or beta-blocker therapy.

The authors report two patients without coronary artery disease who experienced asystole during the IV infusion of dipyridamole on routine TI-201 myocardial perfusion imaging and review the literature for possible explanations of this rare side effect. Until now, this side effect was only reported in patients with coronary artery disease or beta-blocker therapy. Yet, the cases lacked both concomitant factors and autonomic dysregulation is suggested as a cause for asystole.

Adrenergic beta-Antagonists↗
PubMed1997

Enhanced hematopoiesis in sublethally irradiated mice treated with various quinolones.

We compared the effect of 6 quinolones on growth of murine bone marrow (BM) progenitor cells in vitro, and their in vivo effect on repopulation of BM and on survival of sublethally irradiated mice. The addition of clinically attainable concentrations of ciprofloxacin, sparfloxacin or clinafloxacin, in concert with pokeweed mitogen (PWM) to murine spleen cells, resulted in a significant enhancement in colony stimulating activity. A 1.5-1.8 fold increase in the number of myeloid progenitors (CFU-C) was observed in the presence of quinolone-PWM spleen conditioned medium (SCM) (prepared with the above-mentioned quinolones) compared with control cultures exposed to PWM-SCM only. Three other quinolones showed either no stimulatory-effect (fleroxacin, norfloxacin) or had an inhibitory effect (ofloxacin) on CFU-C growth. The stimulatory quinolones share in common a cyclopropyl moiety at position N1 of the quinolone ring. This moiety is lacking in the other 3 quinolones. The secretion of interleukin-3 (IL-3) and granulocyte-macrophage colony-stimulating factor (GM-CSF) by murine spleen cells exposed to quinolone-PWM-SCM was significantly enhanced with all 6 quinolones. However, this effect was associated with a parallel increase in CFU-C only with ciprofloxacin (10 micrograms/mL), sparfloxacin (1 microgram/mL) and clinafloxacin (0.05 microgram/mL). The in vivo activity was assessed in sublethally irradiated mice (650 rad) treated with quinolones for 5 d. The number of CFU-C in BM and the number of peripheral white blood cells (WBC) 8 d post-irradiation was significantly enhanced in mice treated with ciprofloxacin (45 mg/kg/d), sparfloxacin (22.5 mg/kg/d) and clinafloxacin (11.25 mg/kg/d) compared to saline treated animals (p < or = 0.05). Clinafloxacin at higher dosage (45 mg/kg/d) resulted in a decrease in myeloid progenitors in BM. A similar increase in progenitors and WBC was observed in animals treated with high doses, above clinical relevance, of ofloxacin, and norfloxacin (90 mg/kg/d), and with fleroxacin (45 and 90 mg/kg/d). Quinolone-treated animals, at the above-cited doses, showed enhanced survival on d18 compared to saline treated animals. The only exception was the higher mortality of clinafloxacin-treated mice. The above observations imply that certain quinolones, sharing specific molecular structure, are potential immunomodulators at clinically relevant concentrations. These compounds should be further studied in neutropenic patients and BM or peripheral blood progenitor cell recipients.

Animals↗
PubMed1996

A prospective study of human herpesvirus type 6 detected by polymerase chain reaction after liver transplantation.

Human herpesvirus type 6 (HHV-6) causes roseola infantum (exanthema subitum) upon primary infection in young children. Thereafter it persists lifelong in the organism. Like other herpesviruses, HHV-6 can be reactivated in periods of immunosuppression - e.g., after organ transplantation. In order to study the incidence and the time to reactivation after orthotopic liver transplantation (OLT) we tested buffy coat lysates before and up to 10 weeks after transplantation for the presence of HHV-6 DNA by polymerase chain reaction (PCR). Forty-six patients (male n=27, female n=19) with a median age of 48 years (range 20-66) were studied. Altogether, 30 of 287 (10.5%) buffy coat samples were PCR-positive. Before OLT 2 of 21 (9.5%) patients were positive. This ratio is not different from healthy blood donor controls. After OLT 13 of 46 (23.8%) patients were positive on one or more occasions. However, there was no statistically significant difference before and after OLT. Ten patients were analyzed for HHV-6 variants by restriction enzyme digestion of PCR products. One patient carried variant A and 9 variant B. In conclusion, HHV-6 can be detected in buffy coat cells after OLT. Our observations do not argue in favor of a reactivation.

Adult↗
PubMed1996

Short-term compliance with peak flow monitoring: results from a study of inner city children with asthma.

The objective of the study was to assess the feasibility of initiating daily peak flow monitoring in a research study of asthma in inner city children. We performed a descriptive study of patterns of peak flow monitoring in children randomized to receive a simple mini-Wright (SM) or an electronic recording meter (ERM). The ERM served as a "covert" meter, providing objective documentation of actual peak flow use. Sixty-five Hispanic or African-American children, ages 5-9 years, with a history of physician-diagnosed asthma participated in the study. All children resided in census tracts with 40% or more of the population living at or below the poverty level. Subjects were instructed to use a peak flow meter (the SM or ERM) at least twice daily over a 3 week period, and to record peak flow values in a paper diary. Subjects who received the ERM were not made aware that measurements were also recorded electronically. Differences in patterns of use of the SM and ERM were assessed with the Wilcoxon signed rank test and Wilcoxon sum rank test. Adherence to peak flow monitoring was evaluated by comparing the percent days with missing values in the manually completed diary with those obtained by computer record. The Friedman statistic was used to compare changes in compliance (percent of days with missing peak flow entries) over time. Accuracy of peak flow readings was assessed by comparing the manual and electronic recordings with paired and unpaired t-tests and with Pearson product moment correlations. The percent of days with missing peak flow entries on diaries increased from 1.4% to 10.6% from the first to third week of monitoring (P < 0.004). The ERMs indicated a significantly greater percent of missing data than did the manual records (P < 0.0002). The difference in the percent of missing data for the electronic and manual records was most notable during the third study week, when the ERM and the manually completed records indicated that 52% and 15% of days, respectively, were without peak flow measures. Large inter-subject variations in the relationship between manually and electronically recorded peak flow measurements were observed, suggesting that errors in reading and transcribing peak flow rates occur in a subset of asthmatics. We conclude that children and caretakers in the inner city may have considerable difficulty initiating and maintaining peak flow recordings. Data obtained by manual records may considerably overestimate actual use. Compliance with monitoring decreases markedly between the first and third week of monitoring.

Black or African American↗
PubMed1996

A new urea broth-based test to detect Helicobacter pylori presence in upper gastrointestinal biopsies.

The aim of this study was to evaluate the performance of a simple and inexpensive homemade urea test (U-test) to detect Helicobacter pylori in upper digestive tract biopsies. We tested and compared the U-test with three other diagnostic methods: the Clo-test, and culture and pathology in 110 patients randomly chosen at the endoscopy clinic. When using culture and/or pathology as the "gold standard," H. pylori was found to exist in 54 patients. Pathology was positive in 50 cases (92.5%), culture in 49 (90.7%), the U-test in 45 (83.3%), and the Clo-test in 43 (79.6%). With regard to culture pathology, the sensitivities of the U-test and the Clo-test were 83.3% and 79.5%, respectively. Specificity was 100% for both methods. The kappa coefficient calculation between the U-test and the Clo-test was 0.98. The results show that the U-test is a reliable, fast, and inexpensive method for detecting H. pylori in upper gastrointestinal biopsies.

Adult↗
PubMed1996

Pulmonary thromboembolism: epidemiology and techniques of nuclear medicine.

Pulmonary thromboembolism is a very common disease (about 500,000 events per year in the United States). The most important risk factors seem to be age, cancer, previous surgery, trauma, coagulation disorders, and immobilization. Analysis of epidemiologic studies shows that the incidence of pulmonary embolism is underestimated clinically. Combined ventilation/perfusion scintigraphy is an established method for the diagnosis of pulmonary embolism, but the specificity of the method still is not high enough. Diagnostic strategies and new techniques in nuclear medicine will probably be able to improve the quality of the management of patients with clinically suspected pulmonary embolism.

Humans↗
PubMed1996

Pulmonary embolism. II. Diagnosis and treatment.

Pulmonary embolism is an often underestimated, underdiagnosed, and undertreated disease. As symptoms and signs of pulmonary embolism are nonspecific, the diagnosis still remains a challenge to the attending physician. Diagnostic and therapeutic procedures depend on the clinical presentation of the patient. First we must suspect pulmonary embolism and consider its likelihood in the presence of a number of clinical signs and symptoms. Once pulmonary embolism is suspected, heparin should be administered. Additional basic support is mandatory if required. If the patient's hemodynamic situation is stable, available preferable noninvasive diagnostic options should be considered to confirm or rule out the diagnosis of venous thromboembolism before further administration of anticoagulant or thrombolytic agents. If the patient's status has deteriorated, bedside diagnostic techniques should be applied to reinforce the suspicion or establish the diagnosis. To restore pulmonary perfusion more rapidly than conventional anticoagulation is suspected to do, several dosing regimens of thrombolytic agents are proposed, with recent interest in short-term thrombolysis and bolus lysis with urokinase or recombinant tissue plasminogen activator. If thrombolysis fails or is contraindicated, catheter embolectomy or surgical embolectomy is indicated. The main therapy is prevention. In this article, clinical assessment, imaging techniques, and therapeutic options described in the published literature are discussed and clinical experiences of an emergency department with a noninvasive diagnostic approach are described.

Causality↗
PubMed1996

Corynebacterium striatum meningitis: case report and review of an increasingly important Corynebacterium species.

For a long time, corynebacteria were considered simple cutaneous contaminants with little potential pathogenicity. Corynebacterium striatum is a known saprophytic cutaneous bacterium; however, in the last decade, this organism has been increasingly recognized as a pathogen. It has been mostly implicated in respiratory tract and blood infections. To our knowledge, we report the first case of meningitis due to C. striatum. Treatment with intravenous vancomycin resulted in therapeutic success. We also thoroughly review all previously reported cases of C. striatum infection. Identification of Corynebacterium species can be difficult because of rapid taxonomic changes, and susceptibility testing for these microorganisms is not yet standardized. However, because of their growing clinical importance, data on these bacteria are accumulating.

Adult↗
PubMed1996

Comparison of antimicrobial susceptibilities of Corynebacterium species by broth microdilution and disk diffusion methods.

Corynebacterium species are increasingly being implicated in foreign-body infections and in immunocompromised-host infections. However, there are no specific recommendations on the method or the criteria to use in order to determine the in vitro activities of the antibiotics commonly used to treat Corynebacterium infections. The first aim of our study was to compare the susceptibilities of various species of Corynebacterium to vancomycin, erythromycin, and penicillin by using a broth microdilution method and a disk diffusion method. Second, the activity of penicillin against our isolates was assessed by using the interpretative criteria recommended by the National Committee for Clinical Laboratory Standards for the determination of the susceptibility of streptococci and Listeria monocytogenes to penicillin. Overall, 100% of the isolates were susceptible to vancomycin, while considerable variations in the activities of erythromycin and penicillin were noted for the different species tested, including the non-Corynebacterium jeikeium species. A good correlation in the susceptibilities of vancomycin and erythromycin between the disk diffusion and the microdilution methods was observed. However, a 5% rate of major or very major errors was detected with the Listeria criteria, while a high rate of minor errors (18%) was noted when the streptococcus criteria were used. Our findings indicate considerable variations in the activities of erythromycin and penicillin against the various species of Corynebacterium. Because of the absence of definite recommendations, important discrepancies were observed between the methods and the interpretations of the penicillin activity.

Anti-Bacterial Agents↗
PubMed1995

Lethal Waterhouse-Friderichsen syndrome in posttraumatic asplenia.

We herein report a case of fulminant lethal Waterhouse-Friderichsen syndrome in an elderly female patient seven years after posttraumatic splenectomy. In contrast to various reports, this patient had not been vaccinated against Streptococcus pneumoniae, Neisseria meningitidis, or Haemophilus influenzae, respectively, although infections with these microorganisms are known to cause the main lethal diseases in asplenic patients. Again, we recommend obligatory vaccinations against the mentioned bacteria for it is known that this decreases the risk of fatal septic events in these patients. To optimize prevention, it is imperative to vaccinate patients undergoing splenectomy before discharge from hospital.

Blood Coagulation Tests↗
PubMed1995

Routine susceptibility testing of four antibiotic combinations for improvement of laboratory guide to therapy of cystic fibrosis infections caused by Pseudomonas aeruginosa.

Previous studies have demonstrated synergy between an aminoglycoside and a beta-lactam for treating Pseudomonas aeruginosa infections. Cystic fibrosis patients are prone to infection by this bacterium, which becomes very resistant with recurrent antibiotic treatments. The purpose of this study was to evaluate the susceptibility patterns of 122 isolates of P. aeruginosa isolated from cystic fibrosis patients to five individual antibiotics (tobramycin, ceftazidime, piperacillin, ticarcillin, and imipenem) and to four antibiotic combinations (tobramycin associated with one of the other antibiotics). Strains were selected because of their resistance to individual antimicrobial agents, which ranged from 21.3% for imipenem to 56.5% for tobramycin. By using an automated broth microdilution method, we were able to demonstrate synergy against 39 strains (32%) with tobramycin-ticarcillin, against 38 strains (31%) with tobramycin-piperacillin, against 47 strains (39%) with tobramycin-ceftazidime, and against 23 strains (19%) with tobramycin-imipenem. Of the 122 isolates, 77 (63%) were rendered significantly susceptible to at least one of the four antibiotic combinations by synergy. These results suggest that when appropriate technology is available, susceptibility to antibiotic combinations greatly improves the guide to antibiotic therapy for infections due to P. aeruginosa in cystic fibrosis patients.

Aminoglycosides↗
PubMed1995

Hepatitis C: what a dentist should know.

During the last two decades, the existence of a blood-borne virus responsible for non-A, non-B hepatitis was suspected but not identified. In the United States, an estimated 170,000 cases of post-transfusion hepatitis, many of which became chronic, were attributed to the unknown virus. Recently, however, the virus has been identified and more has been learned about the disease. This review will focus on recent advances regarding the virus and its implications for dental practice.

Dentistry↗