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Biomedical subjects

R Weber

Publications and source records attributed to R Weber.

At least 145 records · Page 8Linked to original sources
PubMed1998

Serological evidence of human granulocytic ehrlichiosis in Switzerland.

To investigate whether human granulocytic ehrlichiosis (HGE) is prevalent in Switzerland, 1515 human serum samples from individuals with different risks for tick exposure were tested for antibodies to Ehrlichia phagocytophila, a surrogate marker of the agent of HGE. The distribution of titres showed marked differences between sera of individuals with no or low risk for tick exposure and those with a high risk. The results of serological testing provided evidence of HGE in Switzerland as well as evidence of two types of coinfections: those with the agent of HGE and Borrelia burgdorferi, and those with the agent of HGE and the central European tickborne encephalitis virus.

Antibodies, Bacterial↗
PubMed1998

Elimination kinetics and toxicity of 2,3,7,8-tetrachlorothianthren, a thio analogue of 2,3,7,8-TCDD.

In comparison to the polychlorinated dibenzo-p-dioxins (PCDD) informations on their thio analogues the polychlorinated thianthrens (PCTA) are very limited. In this study we investigated the kinetics and toxicity of 2,3,7,8-tetrachlorothianthren (TCTA), the analogue of the most toxic PCDD congener 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). It was found that TCTA is rapidly eliminated in mouse liver homogenate fortified with an NADPH-regenerating system suggesting rapid metabolic degradation by liver monooxygenases. Furthermore, TCTA was rapidly eliminated from mouse liver and whole body. In accordance with this rapid elimination, a weekly dosage of 1mg TCTA per kg body weight (i.p.) over six weeks did not result in weight loss or other signs of overt toxicity in male mice. In rat hepatocytes in primary culture, TCTA was active as inducer of dioxin receptor-regulated cytochrome P4501A1 activity measured as 7-ethoxyresorufin O-deethylase (EROD). The relative inducing potency was about 0.0001 in comparison to TCDD. In spite of this molecular effects, the rapid elimination both in vitro and in vivo argues against a consideration of a TCDD equivalency factor for TCTA.

Animals↗
PubMed1998

Extranasopharyngeal angiofibroma in a 15-month-old child.

Angiofibromas are usually characterized by typical location with involvement of the posterior nasal cavity and nasopharynx. They are most commonly found in adolescent males. Despite these facts, a case of an angiofibroma presented in a 15-month-old boy at an atypical site anterior and medial to the lacrimal sac. The tumor was resected via an endonasal, micro-endoscopic approach avoiding an external incision.

Angiofibroma↗
PubMed1998

Treatment of patients with extreme maxillary atrophy using sinus floor augmentation and implants: preliminary results.

Twenty consecutive patients with extreme maxillary atrophy underwent bilateral sinus floor augmentation, either with autogenous bone from the iliac crest or with a combination of autogenous bone and hydroxyapatite. One patient was treated using autogenous bone from the chin region. After a period of three to eight months, three to four implants were placed in each posterior maxilla. Only 10 out of 155 inserted implants were located in the anterior non-augmented maxilla. During the observation period of one to six years, four implants (one of them located in the anterior maxilla) had to be removed prior to prosthetic treatment. Another three implants were lost during the follow up period. This corresponds to a Kaplan-Meier survival probability of 95.4% after 70 months. No statistically significant difference in implant success was observed between women and men (P=0.16). All prosthetic suprastructures are still in function despite these implant losses. Mean peri-implant bone resorption was 1.34 mm with no statistically significant difference between implants placed more mesially and those placed more distally in the augmented area, though a trend could be observed (P=0.058) for a more pronounced bone resorption around implants placed in the premolar region. When a mean mesial and distal bone resorption of >2 mm was considered in the calculation of the success prognosis, the survival probability dropped to 74.7% after 70 months.

Adult↗
PubMed1998

Comparison of immunohistochemical and biochemical measurement of steroid receptors in primary breast cancer: evaluation of discordant findings.

Tumor samples of 240 patients with primary breast cancer were biochemically and immunohistochemically investigated for estrogen receptors (ER) and, in 130 of the samples, for progesterone-receptors (PgR) in order to examine reasons for discordant findings. The biochemical (DCCA) and immunohistochemical assays (ICA) yielded positivity in 71% for ER, and in 44% for PgR. Concordant ER-DCCA and ER-ICA results were obtained in 84%; two thirds of the discordant ER-findings manifested as DCCA-neg/ICA-pos. Concordance in the case of PgR amounted to 72%, and of the discordances 60% were DCCA-neg/ICA-pos. Significant association with postmenopausal status existed only for ER positivity in ICA (p = 0.01), whereas ER-DCCA, PgR-DCCA and PgR-ICA were all more or less independent of the menopausal status. The frequency of discordances was independent of menopausal status. Discordance for ER-assays increased significantly near the respective cut-off point; this was not unequivocally true for PgR-assays. The correlation of tumor types of sparse cellularity, as well as prominent stroma content ('scirrhous carcinoma') with increased frequency of the constellation DCCA-neg/ICA-pos was of borderline significance for PgR (p = 0.06), but not for ER. The percentage of discordant ER-findings, figuring as DCCA-neg/ICA-pos, was statistically significantly increased in locally advanced breast cancer (p = 0.03). Fibrocystic disease in peritumoral breast tissue had no impact on receptor-assay discordance. In any case, the models derived from theoretical thought, laboratory data and singular observations can only in part explain the discordance in steroid receptor values measured with different methods.

Adult↗
PubMed1998

[Experiences in diagnosis of occult traumatic dural lesions of the anterior cranial base].

BACKGROUND: Meningitis or cerebrospinal fluid rhinorrhea can occur years or even decades after trauma and can be the first indication of a previously unidentified dural lesion. In spite of being difficult, precise localization of an occult traumatic dural lesion is a necessary prerequisite for duraplasty. PATIENTS AND METHODS: In a retrospective study covering a period of 17 years, we identified 27 patients with occult traumatic dural lesions. The dural lesions were localized by high-resolution CT, MRI, fluorescein nasal endoscopy, and CT cisternography. In all cases the expected dural lesion was demonstrated and treated surgically. RESULTS: In 23 out of 27 patients (85%), the rhinobasal fistula was detected as a bony defect by CT. Furthermore MRI examination in 100% (5/5), a preoperative fluorescein nasal endoscopy in 50% (10/20) and CT cisternography in 56% (5/9) were able to localize the dural lesion. CONCLUSION: We recommend high-resolution CT and MRI as diagnostic tools of choice in searching for occult dural lesions. Fluorescein nasal endoscopy and CT cisternography are justified as invasive techniques if CT and MRI are inconclusive but clinically CSF leakage is still suggested. The patient will remain at risk of potentially fatal meningitis until the lesion is appropriately repaired by duraplasty. Therefore modern clinical and radiological diagnostic methods should be used to search for an unknown dural lesion.

Cerebrospinal Fluid Rhinorrhea↗
PubMed1998

[Tolerance, subjective complaints and mucociliary clearance in rhinitis sicca before and after nasal irrigation with Rhinomer Force 1].

BACKGROUND: Rhinitis sicca is a widespread disease, caused by a variety of factors. There are many different treatments, but none is more reliable than the other. METHODS: In a prospective study we examined 12 patients before and after a ten-day course of nasal irrigation with Rhinomer Force 1 regarding their symptoms, the mucociliary clearance measured with the saccharin test according to Andersen and tolerance of therapy. RESULTS: Improvement of nose breathing (57%), sensation of mucous running in the pharynx (42%), feeling of a dry nose (42%, significant p = 0.0313). The overall improvement was significant (67%, p = 0.054). Mucociliary transport analysed for each side of the nose (24 sides) resulted in 38% improvement (up 10 min in average), 12% same result, 50% worsening (down 12 min in average). The acceptance was reported as very good in 91% of the study group. CONCLUSIONS: Depending on the symptoms, a high to significant amount of improvement is documented after therapy with isotonic salt water solution. In our study the measurement of the mucociliary transport does not correlate with subjective symptoms. It does not appear to be an adequate tool for diagnosing rhinitis sicca or evaluating the success of treatment.

Adult↗
PubMed1998

[Complications with permanent damage in endonasal paranasal sinus operations--more frequent in experienced surgeons?].

BACKGROUND: The rate of serious complications in endonasal sinus surgery has not gone down although optical aids are widely used nowadays. Are serious complications caused more often by unexperienced or experienced surgeons using a microscope and/or endoscope? METHODS: We defined serious complications as follows: death, persistent neurological deficits or permanent loss of vision, and injury to the internal carotid artery. Two different studies were made: the first consecutive 300 interventions of 6 sinus surgeons were evaluated. Sixteen malpractice cases were analysed regarding the experience of the surgeon. RESULTS: In 9 out of 16 malpractice cases serious complications were attributable to experienced surgeons, five to moderately experienced surgeons, and only two to an inexperienced surgeon (although he had extensive experience in external sinus surgery). There were 6 deaths, 6 neurologic defects, 2 visual disorders, and 2 injuries to the internal carotid artery without any sequelae. In 9 cases the serious complications were related to injury of the internal carotid artery, in five cases to perforation of the skull base. Twice the orbital wall was penetrated. In 1800 procedures performed by 6 surgeons, no serious complications were encountered. There were only lesions of the periorbit (n = 33) or CSF leaks (n = 8) without any permanent damage to the patient. CONCLUSIONS: Even an experienced surgeon must always keep in mind that serious complications can occur in sinus surgery. One must constantly be alert to the possibility of anatomical variants or specific pathologic findings.

Cause of Death↗
PubMed1998

Dual microsporidial infection due to Vittaforma corneae and Encephalitozoon hellem in a patient with AIDS.

A 46-year-old human immunodeficiency virus-infected Swiss citizen living in Tanzania presented with respiratory, abdominal, and urogenital complaints. Microsporidial spores were isolated from urine and a sinunasal aspirate and were propagated in MRC-5 cell cultures. Western blot analysis and riboprinting identified the sinunasal isolate as Encephalitozoon hellem. Electron microscopic investigation of the urine isolate revealed spores with diplokaryotic nuclei and five to six isofilar coils of the polar tube and sporonts with two or three diplokarya. All stages were enveloped by two membranes, corresponding to a cisterna of host endoplasmic reticulum studded with ribosomes. These characteristics have been described for the genus Vittaforma. Western blot analysis of this isolate revealed a banding pattern identical to that of the Vittaforma corneae reference isolate. Part of the small subunit rRNA gene was amplified, sequenced (239 base pairs), and found to be identical to that of V. corneae. This is the second isolation of V. corneae and the first description of urinary tract infection due to V. corneae in a patient with AIDS.

AIDS-Related Opportunistic Infections↗
PubMed1998

Enteroaggregative Escherichia coli as a potential cause of diarrheal disease in adults infected with human immunodeficiency virus.

Stools of 68 human immunodeficiency virus (HIV)-infected adults with diarrhea and 60 without diarrhea were examined for enteroaggregative Escherichia coli (EAggEc) by HeLa cell adherence assay. EAggEc were present in stools of 30 patients with and 18 without diarrhea (P = .05). CD4 cell counts of patients with EAggEc and diarrhea were significantly lower than those of patients with EAggEc without diarrhea (P = .02). There was no difference in the mean duration of diarrheal symptoms or in the number of stools per day between patients with EAggEc and those without. None of the EAggEc strains were positive by polymerase chain reaction for adherence fimbria, but 11 strains were positive for EAggEc heat-stable toxin EAST/1. Of the EAggEc strains, 51% were resistant to trimethoprim-sulfamethoxazole and 65% were resistant to ampicillin. EAggEc may be a pathogen in HIV-infected patients with diarrhea; HIV-infected patients with EAggEc appear to be more symptomatic when HIV disease is more advanced.

AIDS-Related Opportunistic Infections↗
PubMed1998

Aggressive fibromatosis involving the cranial base in children.

OBJECTIVE: Aggressive fibromatoses are proliferations of fibrous tissue that infiltrate surrounding tissues and tend to recur after surgical resection. We report a series of five children with aggressive fibromatosis involving the cranial base. METHODS: A search of the database maintained by the Medical Informatics Department at The University of Texas M.D. Anderson Cancer Center identified 78 patients with aggressive fibromatosis of the head and neck. Of these patients, five demonstrated involvement of the cranial base. All five were children. A retrospective review of the charts, diagnostic images, and pathological findings for these five patients was performed. RESULTS: Surgery, radiotherapy, chemotherapy, and hormonal therapy were the treatment methods used. Four patients underwent gross total resections, but tumor cells were present at the margins in all cases. Two of these four patients experienced recurrences; one patient was cured of disease by a second surgical resection and radiotherapy, and the other underwent a second gross total resection. The fifth patient underwent a subtotal resection. He has experienced four recurrences and continues to live with residual disease. One transformation to a Grade 2 fibrosarcoma was observed. CONCLUSION: Fibromatoses of the cranial base are rare and seem to be most common in the pediatric age group. Gross total resection, preferably in the first attempt, should be the goal. Radiotherapy and hormonal therapy are useful adjunctive methods for the treatment of aggressive fibromatosis. Fibromatoses that involve the cranial base are most likely to require a multidisciplinary treatment approach.

Adolescent↗
PubMed1998

Rapid diagnosis of pulmonary tuberculosis with the LCx Mycobacterium tuberculosis assay and comparison with conventional diagnostic techniques.

The LCx MTB amplification assay is a nucleic acid amplification test intended for the direct detection of Mycobacterium tuberculosis complex in respiratory specimens. We evaluated its performance on 2,001 consecutive respiratory specimens; 78 were culture positive for M. tuberculosis. Sensitivity, specificity, and positive and negative predictive values of this assay for all specimens compared to culture results were 88.5, 97.7, 60.5, and 99.5%, respectively. When referred to resolved clinical diagnosis of active tuberculosis, these values improved to 90.2, 98.4, 72.8, and 99.5%, respectively.

Bronchoalveolar Lavage Fluid↗
PubMed1998

Blinded, externally controlled multicenter evaluation of light microscopy and PCR for detection of microsporidia in stool specimens. The Diagnostic Multicenter Study Group on Microsporidia.

The quality parameters for the detection of microsporidia in identical sets of 50 stool samples were determined for six laboratories where technicians used light microscopy and for six laboratories where technicians used PCR. The average overall sensitivities were 67% (89% for patient samples only) for the PCR laboratories and 54% (80% for patient samples only) for the light microscopy laboratories. Specificities were 98 and 95%, respectively. Differences in results were most apparent between the individual laboratories rather than between the two major methods used.

Animals↗