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Biomedical subjects

R Weiss

Publications and source records attributed to R Weiss.

At least 91 records · Page 5Linked to original sources
PubMed1999

Isoforms of the major allergen of birch pollen induce different immune responses after genetic immunization.

BACKGROUND: Recent publications indicate that immunization with plasmid DNA encoding allergens might represent a potential approach in allergen-specific immunotherapy. OBJECTIVE: In the present study we have compared the immune responses induced by plasmid DNA encoding for two isoforms of Bet v 1, the major allergen of birch pollen. METHODS: BALB/c mice were injected intradermally with plasmid DNA encoding for the genes of Bet v 1a (pCMV-Beta) and Bet v 1d (pCMV-Betd). In addition, the effect of immunostimulatory DNA sequences was investigated by appending and/or coinjecting CpG motifs. Antibody responses and IFN-gamma and IL-4 levels were measured by ELISA. Allergen-specific proliferation was determined by incorporation of [(3)H]-thymidine. RESULTS: The two isoforms induced a similar humoral response. The lack of any IgE production and the ratio of IgG1 to IgG2a clearly indicated a Th-1-type response. The antisera against both isoforms were highly cross-reactive, which was supported by the energy plot indicating similar folding of the two protein isoforms. However, determination of IFN-gamma and IL-4 in the serum elicited a strikingly different cytokine profile during the course of the immune response. In contrast to pCMV-Beta, pCMV-Betd caused no significant allergen-specific proliferation and induced only marginal levels of the key cytokines. CONCLUSIONS: Based on the assumption that the induction of a strong Th-1 type response is a prerequisite for successful treatment of allergy, our results favor the use of isoform Bet v 1a in combination with CpG motifs for a novel type of allergen immunotherapy based on plasmid DNA immunization. Additionally, the data also confirm the assumption that the antigen itself can have a marked influence on the immune response after genetic immunization.

Allergens↗
PubMed1999

Rhizopusmycosis in a harbor porpoise from the Baltic Sea.

A case of systemic mycosis due to a Rhizopus sp. infection is described in a dead-stranded, 10-yr-old, male harbor porpoise (Phocoena phocoena) found on the beach of Neustadt, Schleswig-Holstein on the Baltic Sea (Germany). At necropsy, granulomatous mycotic lesions in brain, lung, kidneys, testis, and draining lymph nodes were found. In addition, a focal ulcerative gastritis of the first stomach, due to a nematode infection, was present and is suspected to be the portal of entry for the fungus.

Animals↗
PubMed1999

Serum antibodies against particular antigens of Borrelia burgdorferi sensu stricto and their potential in the diagnosis of canine Lyme borreliosis.

Dog sera (n = 118) were tested for antibodies recognizing Borrelia (B.) burgdorferi sensu stricto strain B31 (ATCC 35210) antigens. In total, 18 of the dog sera gave positive results in a whole cell sonicate ELISA (WCS ELISA). These positive sera were further evaluated by immunoblot assay, utilizing a whole bacterial lysate as antigens. 94.4% (17 of 18) of the dog sera reacted with immunodominant antigens at 20-22 kDa (protein C, pC), 31 kDa (outer surface protein A, OspA), 34 kDa (outer surface protein B, OspB), 41 kDa (flagellin), 60 kDa ("common antigen"), and/or 100 kDa (presumably p100). Sera recognizing pC (20-22 kDa) and antigens > 94 kDa always detected the highest number of antigen bands, indicating the specificity of those antigens in serological diagnosis. The results clearly demonstrate that the WCS ELISA is a useful tool for testing sera of dogs for antibodies against B. burgdorferi. However, positive results should be confirmed by immunoblot, using WCS as antigen. According to the presented data, we recommend criteria for B. burgdorferi immunoblots using dog sera as follows: sera have to be considered as positive if they detect the 41 kDa flagellin, and two of the 5 immunodominant antigens, namely > 94 kDa (presumably p100), 60 kDa ("common antigen"), 34 kDa and 29-31 kDa (OspB and OspA, respectively) and 20-22 kDa (pC). If sera only recognize the 41 kDa flagellin, this result is equivocal, requiring testing a second serum sample 4 to 8 weeks later.

Animals↗
PubMed1998

Acute changes in spontaneous echo contrast and atrial function after cardioversion of persistent atrial flutter.

With use of transesophageal echocardiography, the short-term effects of transthoracic electrical cardioversion of atrial flutter (AFI) on atrial mechanical function and spontaneous echo contrast were determined. Thirty patients who had AFI for a mean of 6.4 +/- 12.2 months underwent transthoracic cardioversion. A transesophageal echocardiogram was recorded immediately before cardioversion, and left atrial appendage emptying velocity and spontaneous contrast were assessed serially at 1, 3, and 5 minutes after cardioversion in 28 patients, and also at 8, 10, and 15 minutes after cardioversion in a subgroup of 13 patients. Cardioversion was deferred in 2 patients (7%) because a thrombus was found in the left atrial appendage. Before cardioversion, spontaneous contrast was present in the left atrium in 7 of 28 patients (25%) who underwent cardioversion. The mean left atrial appendage emptying velocity of 54 +/- 22 cm/s before cardioversion fell by 26% to 40 +/- 25 cm/s at 1 minute after restoration of sinus rhythm (p <0.01). There were no significant changes in the mean left atrial appendage-emptying velocity between 1 and 15 minutes after cardioversion. Within 5 minutes after conversion to sinus rhythm, left atrial spontaneous echo contrast developed de novo or worsened in 12 of the 28 patients (43%). In conclusion, the results of this study demonstrate that persistent AFI may be associated with left atrial thrombi before cardioversion and that cardioversion of AFI is associated with a significant degree of atrial stunning and formation of spontaneous echo contrast.

Adult↗
PubMed1998

Effectiveness of three different doses of carvedilol for exertional angina. Carvedilol-Angina Study Group.

Carvedilol is a nonselective beta-receptor antagonist with vasodilating properties primarily due to selective alpha-1 antagonism. This 4-treatment, 5-period, double-blind, crossover study evaluated the efficacy and safety of 3 doses of carvedilol (12.5, 25, and 50 mg given twice daily) versus placebo in 122 patients with chronic stable angina. Carvedilol in doses of 25 mg twice daily and 50 mg twice daily was statistically superior to placebo with respect to time to angina (placebo: 316 seconds; 25 mg carvedilol: 337 seconds, p = 0.0039; 50 mg: 345 seconds, p <0.0001) and time to 1-mm ST-segment depression (placebo: 301 seconds; 25 mg: 313 seconds; 50 mg: 323 seconds; p <0.0001). The percentage of patients reporting any adverse experience was slightly less in those receiving placebo (placebo: 28.4%; 12.5 mg: 33.1%; 25 mg: 34.5%; 50 mg: 31.9%). Carvedilol is effective and safe in treating patients with chronic stable angina.

Aged↗
PubMed1998

Predictors of dropout from psychosocial treatment of cocaine dependence.

The current study assessed demographic, drug and psychiatric predictors of dropout in the pilot/training phase of a large, multi-site psychotherapy outcome study for patients with cocaine dependence. The different predictors of dropout were assessed throughout the phases of the study: screening, intake, stabilization and assessment phase, and following randomization to treatment. Results showed that (1) younger patients were less likely to keep their intake appointment. (2) Of the patients who had an intake visit, those who did not complete high school and with more days of cocaine use in the previous month were less likely to complete an initial stabilization and assessment phase requiring 1 week of abstinence from all drugs. A survival analysis was used to examine time to dropout for the 286 patients randomized to individual treatment. (3) Again, younger age was associated with dropout after randomization. (4) Drug use variables did not predict time to dropout. (5) Presence of any current Axis I disorder was associated with later dropout from treatment. Minority treatment information seekers and treatment initiators were less likely to go on to complete the full treatment program.

Adult↗
PubMed1998

The relationship between cardiothoracic ratio and left ventricular ejection fraction in congestive heart failure. Digitalis Investigation Group.

BACKGROUND: Left ventricular ejection fraction (EF) is a valuable prognostic index in patients with congestive heart failure (CHF). Although EF can be readily measured, many clinicians use roentgenographic heart size as a clue to differentiate systolic from diastolic dysfunction, even in the absence of solid supportive data. OBJECTIVE: To test the hypothesis that the cardiothoracic ratio (CTR) measured from the chest roentgenogram can be used to estimate left ventricular EF in individuals with CHF. METHODS: To answer this question, the database of the Digitalis Investigation Group trial was used. The CTR, determined using the Danzer method, and quantitative EF, measured locally using angiographic, radionuclide, or 2-dimensional echocardiographic techniques, were compared in 7476 patients with clinical CHF (New York Heart Association functional classes I-IV) due to acquired left-sided cardiac disease of ischemic, hypertensive, idiopathic, and alcohol-related causes. RESULTS: Mean (+/-SD) CTR for the cohort was 0.53+/-.07. Mean (+/-SD) EF was 31.7%+/-12.2%. A weak, negative correlation between CTR and EF was observed (r=-0.176). Similar findings were obtained when the results were stratified by cause of CHF, presence of clinically defined right ventricular dysfunction, and method of EF measurement. Categorical analysis failed to yield a CTR cutoff point that facilitated useful segregation of individuals with an EF greater than 35% or 35% and below; greater than 40% or 40% and below; and greater than 45% or 45% and below in any patient group. CONCLUSIONS: Although a weak, negative correlation exists between CTR and EF, this relationship does not allow for accurate determination of systolic function in individual patients with CHF. Considering the morbidity and mortality associated with CHF, and the clinical implications of systolic function in this syndrome, direct measurement of EF is recommended.

Aged↗
PubMed1998

Smoking in adult survivors of childhood acute lymphoblastic leukemia.

BACKGROUND: Health-related behaviors are of particular concern in survivors of childhood cancer as they are at increased risk for second cancers and long-term organ dysfunction. The purpose of this study was to compare the smoking behavior and associated factors in young-adult survivors of childhood acute lymphoblastic leukemia (ALL) with those in sibling controls. METHODS: A telephone interview that surveyed smoking behavior was conducted with 592 young-adult survivors, treated before age 20 years on Children's Cancer Group ALL protocols, and 409 sibling controls. Using stratified chi-squared analyses and Cox proportional hazards models, we compared the rates of smoking initiation and smoking cessation between survivors and control subjects. Demographic characteristics (age, sex, race, and education) and psychological factors (mood and self-concept) were examined as predictors interacting with survivorship in logistic regression analyses to try to distinguish a subgroup of survivors who may be at greater risk for smoking. RESULTS: Survivors were significantly less likely to have ever smoked (23.0% versus 35.7%; P<.0001) and thus were less likely to ever be regular, daily smokers than sibling controls (19.1% versus 31.3%; P<.0001). Survivors were less likely to quit smoking than sibling controls (26.6% versus 35.2%), although this result was not statistically significant. There were no interactions between survivor status and either demographic or psychological features on smoking behavior. CONCLUSIONS: Young-adult survivors of childhood ALL are less likely to experiment with smoking but, once having started, are at similar risk for becoming habitual, persistent smokers as sibling controls.

Actuarial Analysis↗
PubMed1998

[Asylum seekers and refugees in general practice: problems and possible developments].

Health and health services provided to asylum seekers and refugees by the Swiss National Health System have so far not been systematically investigated. The aim of this cross-sectional study was to describe the attending asylum seekers and refugees demographically and clinically, to identify main problem areas as perceived by general practitioners and to highlight options and venues for improvements. 272 questionnaires have been filled in by GPs of eight "federal districts" (Kantone) and the consultations of 1477 asylum seekers and refugees have been documented during one month in 193 surgeries. The documented asylum seekers and refugees reflected the distribution of this population in Switzerland. Low consultation rates of asylum seekers and refugees in the majority of surgeries and high diversity of this population in respect to places of origin, education and proficiency in languages appear to be the major determinants of the difficulties in providing adequate health services to them. Readily available information on the past medical history and on the ethnic background of these patients and continuing education on specific topics concerning health care for asylum seekers and refugees were thought to be particularly useful. This needs to be considered in the planning of services for this group. General practitioners specialized in health care for asylum seekers and refugees is an option for providing improved specific services (interpreters, institutional links, culturally adapted medical care).

Adolescent↗
PubMed1998

Cardiac electrophysiologic effects of norepinephrine in human beings.

BACKGROUND: The electrophysiologic effects of norepinephrine (NE) in human beings have not been previously described. METHODS: The electrophysiologic effects of NE infused at a rate of 25 ng/kg/min were determined in 21 patients with a mean age of 41 +/- 11 years and without structural heart disease who underwent an electrophysiology procedure. In a subgroup of 10 patients electrophysiologic parameters were measured at baseline, after the infusion of NE, and after administration of beta-blockade while in continuous NE infusion. RESULTS: The baseline NE plasma concentration of 298 +/- 153 pg/ml increased to 708 +/- 419 pg/ml after the infusion of NE. NE significantly increased the mean blood pressure, sinus cycle length, corrected sinus node recovery time, ventriculoatrial block cycle length, and the atrial and ventricular effective refractory periods. In a subset of 10 patients 0.2 mg/kg propranolol administered during continued infusion of NE resulted in a further increase in sinus cycle length, atrial-His interval, and ventricular refractoriness. CONCLUSION: A physiologic elevation in the plasma NE concentration results in a depression of sinus node function and atrioventricular conduction and in prolongation of atrial and ventricular refractoriness. Some of NE's effects are partially offset by beta-adrenergic stimulation.

Adrenergic alpha-Agonists↗
PubMed1998

Effect of isoproterenol on QRS complex morphology during ventricular pacing: implications for pace mapping.

Ventricular pace mapping may be used to identify the site of origin of idiopathic ventricular tachycardia. Isoproterenol is often required to induce this type of ventricular tachycardia, but its effect on QRS morphology during pace mapping is unknown. Therefore, this study was performed to evaluate the effect of isoproterenol on QRS morphology during ventricular pacing. The study population consisted of 20 patients (mean age 38 +/- 14 years) undergoing a clinically indicated electrophysiology procedure. Ventricular overdrive pacing was performed in trains of 12 stimuli at cycle lengths of 400, 350, 300, and 250 ms, first in the baseline state during an infusion of isoproterenol, and again after isoproterenol washout. Pacing was performed at the right ventricular apex in 10 patients, in the right ventricular outflow tract in 6 patients, and in the left ventricle in 4 patients. Visual evaluation revealed no apparent effects of isoproterenol on QRS morphology at any of the three pacing sites or at any of the pacing cycle lengths. It was concluded that QRS morphology during ventricular pacing is not affected by isoproterenol infusion. Therefore, in patients with idiopathic ventricular tachycardia, even if the induction of tachycardia requires infusion of isoproterenol, successful pace mapping may be performed in its absence.

Aged↗
PubMed1998

Unilateral Blastomyces dermatitidis endophthalmitis and orbital cellulitis. A case report and literature review.

PURPOSE: The authors report the clinical, cytologic, and histopathologic findings of a unique presentation of concomitant unilateral endophthalmitis and orbital cellulitis secondary to Blastomyces dermatitidis. DESIGN: Case report. METHODS: A 29-year-old healthy woman with a history of pulmonary tuberculosis presented with a painful right eye and rapidly decreasing vision. Fundus examination showed a diffuse elevated choroidal lesion at the posterior pole. With an otherwise unremarkable systemic work-up, the patient was treated with systemic antibiotics and corticosteroids for a presumed diagnosis of choroidal tuberculous granuloma. After an initial response to the treatment, the patient's condition deteriorated rapidly with visual acuity decreasing from 20/25 to no light perception in 3 months. Ipsilateral proptosis developed with magnetic resonance imaging showing a poorly defined orbital mass. Surgical enucleation and an orbital biopsy were performed. RESULTS: Histopathologic examination of the orbital specimen and an intact enucleated globe showed a diffuse necrotizing granulomatous process with the presence of numerous yeasts consistent with B. dermatitidis. This subsequently was confirmed by positive culture of B. dermatitidis from the orbital specimen. CONCLUSIONS: This is a unique case of concurrent unilateral endophthalmitis and orbital cellulitis secondary to B. dermatitidis. Intraocular dissemination of blastomycosis should be suspected in the differential diagnosis of endophthalmitis in patients with previous or active pulmonary lesions of equivocal nature. Early diagnosis and prompt treatment with antifungal medications are essential.

Adult↗
PubMed1998

Autonomic nervous system activity and the spontaneous initiation of ventricular tachycardia. ESVEM Investigators. Electrophysiologic Study Versus Electrocardiographic Monitoring Trial.

OBJECTIVES: We hypothesized that neurohormonal activity contributes to the initiation of sustained ventricular tachycardia (VT) as reflected in indices of heart rate variability (HRV). BACKGROUND: Autonomic nervous system activity participates in experimental arrhythmias but clinical studies have been inconsistent. METHODS: Holter electrocardiograms from 53 patients with VT were analyzed. Heart rate variability indices were determined over 5 and 15 min and 24 h and examined for changes before the onset of VT. Heart rate variability indices in the frequency domain included ultra low frequency power (FP) (ULFP): 0-0.0033 Hz; very low FP (VLFP): 0.0033-0.04 Hz; low FP (LFP): 0.04-0.15 Hz; high FP (HFP): 0.15-0.4 Hz; total power (TP); normalized LFP (LFPn); normalized HFP (HFPn), and the ratio: LFP/HFP. RESULTS: Heart rate variability indices were severely diminished: TP: 12,009+/-11,076 ms2; ULFP: 10,087+/-9,565 ms2; VLFP: 1,416+/-1,571 ms2; LFP: 544+/-620 ms2; HFP: 161+/-176 ms2, and LFP/HFP: 3.68+/-2.83. Heart rate increased before VT (80.4+/-17.3 to 85.3+/-17.4 bpm, p < 0.001). Several HRV variables declined 30 min before VT compared to 24-h values (VLFP: -5.89+/-17.81%, p = 0.031; LFP: -5.23+/-14.3%, p = 0.003; HFP: -4.35+/-13.7%, p = 0.04). LFPn and the LFP/HFP ratio decreased significantly before the onset of VT (-17.7+/-46.9%, p = 0.035 and -8.24+/-38.8%, p = 0.037, respectively), whereas HFPn increased slightly (4.29+/-29.9%, p = 0.097). CONCLUSIONS: Heart rate rose, whereas LFP, LFPn and LFP/HFP fell before the onset of VT. This pattern of changes could be explained by a rise in sympathetic activity and saturation of the HRV signal resulting in dissociation of the average and rhythmical effects of sympathetic activity. These findings suggest that alterations in autonomic activity contributed to arrhythmogenesis in this group of patients.

Aged↗
PubMed1998

Detection of Borrelia burgdorferi in urine specimens from dogs by a nested polymerase chain reaction.

A nested PCR (nested flagellin PCR) carrying an internal E. coli DNA control was established and compared with an in-vitro culture method for the detection of Borrelia burgdorferi in urine specimens of dogs. The predicted specific amplicon of the flagellin gene fla was generated from all cultured strains of B. burgdorferi tested (comprising three European genospecies). In contrast, all 13 strains of seven other flagellated bacterial species were negative. The PCR detection limit yielded 20 cells of B. burgdorferi per ml of double-distilled water and approx. 250 bacteria per ml of dog urine. Using the bacterial culture method, urine specimens collected from 216 dogs in Germany were all diagnosed negative for spirochetes by in-vitro culture and dark-field microscopy. In contrast, DNA of B. burgdorferi was detected in 32 specimens (14.8%) by PCR. 31 urine specimens (14.4%) showed inhibitory activity in the PCR assay. However, 94 (44%) were inhibitory in the culture assay. The majority of the PCR-positive dogs exhibited major clinical symptoms which have not been reported in the course of B. burgdorferi infection previously, e.g. cystitis (14/32 dogs) or prostatitis (5/32 dogs). Our results indicate that the analysis of urine specimens by the nested flagellin PCR is a highly valuable procedure for the diagnosis of B. burgdorferi infections in dogs.

Animals↗
PubMed1998

Randomized comparison of a 90 uF capacitor three-electrode defibrillation system with a 125 uF two-electrode defibrillation system.

INTRODUCTION: A variety of factors, including the number of defibrillation electrodes and shocking capacitance, may influence the defibrillation efficacy of an implantable defibrillator system. Therefore, the purpose of this study was to compare the defibrillation energy requirement using a 125 uF two-electrode defibrillation system and a 90 uF three-electrode defibrillation system. METHODS AND RESULTS: The defibrillation energy requirements measured with both systems were compared in 26 consecutive patients. The two-electrode system used a single transvenous lead with two defibrillation coils in conjunction with a biphasic waveform from a 125 uF capacitor. The three-electrode system used the same transvenous lead, utilized a pectoral implantable defibrillator generator shell as a third electrode, and delivered the identical biphasic waveform from a 90 uF capacitor. The two-electrode system was associated with a higher defibrillation energy requirement (10.8 +/- 5.5 J) than was the three-electrode system (8.9 +/- 6.7 J, p < 0.05), however, the leading edge voltage was not significantly different between systems (361 +/- 103 V vs. 397 +/- 123 V, P = 0.07). The two-electrode system also had a higher shocking resistance (49.0 +/- 9.0 ohms vs. 41.4 +/- 7.3 ohms, p < 0.001) and a lower peak current (7.7 +/- 2.6 A vs. 10.1 +/- 3.7 A, p < 0.001) than the three-electrode system. CONCLUSIONS: A three-electrode defibrillation system that utilizes a dual coil transvenous lead and a subcutaneous pectoral electrode with lower capacitance is associated with a lower defibrillation energy requirement than is a dual coil defibrillation system with higher capacitance. This finding suggests that the utilization of a pectoral generator as a defibrillation electrode in conjunction with smaller capacitors is a more effective defibrillation system and may allow for additional miniaturization of implantable defibrillators.

Aged↗
PubMed1998

Properties of serological group B streptococci of dog, cat and monkey origin.

This study was designed to identify and characterize further Streptococcus agalactiae isolated during routine diagnostics from three diseased dogs and a cat, as well as from the inner organs of a monkey which died on a sepsis with beta-haemolytic streptococci. The cultures could be identified as streptococci of serological group B by cultural, biochemical and serological properties and by restriction fragment length polymorphism analysis of polymerase chain reaction (PCR)-amplified 16S ribosomal DNA. A further characterization of the isolates by serotyping and by determination of antibiotic resistances revealed a close relationship of these isolates to the human biotype of this species.

Animals↗