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Biomedical subjects

R Weber

Publications and source records attributed to R Weber.

At least 307 records · Page 17Linked to original sources
PubMed1992

Disseminated microsporidiosis (Encephalitozoon hellem) and acquired immunodeficiency syndrome. Autopsy evidence for respiratory acquisition.

Microsporidia are obligate intracellular protozoal parasites that infect a variety of cell types in a broad range of invertebrates and vertebrates. They have recently come to medical attention due to the increased frequency with which members of two microsporidian genera, Enterocytozoon and Encephalitozoon, are being diagnosed in patients with the acquired immunodeficiency syndrome (AIDS). The majority of published reports of human microsporidiosis describe Enterocytozoon infection of small intestinal enterocytes. In addition, a growing number of AIDS patients have been identified with infection due to the two species of Encephalitozoon-Encephalitozoon cuniculi and Encephalitozoon hellem, observed in conjunctival, corneal, and, recently, sinonasal tissues. However, there are scant data regarding the systemic pathology and epidemiology of these infections. This article describes a patient with AIDS who died with systemic Encephalitozoon infection. The etiologic microsporidian was found to be E hellem by using antemortem biochemical and antigenic analyses. A complete autopsy, the first to be reported in a patient with this infection, revealed organisms in the eyes, urinary tract, and respiratory tract. A surprising observation was the occurrence of numerous organisms within the lining epithelium of almost the entire length of the tracheobronchial tree, suggestive of respiratory acquisition. Detailed light and electron microscopic findings and the biological and diagnostic features of microsporidiosis are discussed.

Acquired Immunodeficiency Syndrome↗
PubMed1991

Tumor necrosis factor alpha selectively sensitizes human immunodeficiency virus-infected cells to heat and radiation.

We report here that infection of the human T-cell line HUT-78 with human immunodeficiency virus (HIV) increases its sensitivity to heat and radiation toxicity. A possible explanation for this result may be the reduced expression of manganous superoxide dismutase (MnSOD) in HIV-infected cells compared to uninfected cells. Tumor necrosis factor alpha (TNF-alpha) further sensitizes HIV-infected cells but not uninfected cells to heat and radiation. This is consistent with the ability of TNF-alpha to induce the expression of MnSOD in uninfected but not in HIV-infected cells. HIV-infected HUT-78 cell lines engineered to overexpress MnSOD are more resistant to heat and radiation than HIV-infected cells that do not overexpress MnSOD. However, treatment with TNF-alpha still sensitizes these cells to heat and radiation.

Cell Line↗
PubMed1991

Spontaneous regression of a temporal arachnoid cyst.

Surgery is considered to be the standard therapy for arachnoid cysts (ACs). We report the case of a 13-year-old boy in whom a right temporal AC disappeared spontaneously over a period of 10 years. Bulging of the right temporal skull led to the detection of the cyst by computed tomography (CT) scan at the age of 3 years. There were no other clinical symptoms. Subsequent CT scans showed spontaneous regression of the cyst without surgical intervention. The question as to how ACs should be treated is discussed.

Adolescent↗
PubMed1991

Adult onset lipid storage in gastric mucosa and skeletal muscle fibers associated with gastric pain, progressive muscle weakness and partial deficiency of cytochrome C oxidase.

We report on the first case, a 21-year-old man, with partial deficiency of cytochrome c oxidase, lipid storage myopathy and concomitant lipid storage in the gastric mucosa affecting chief, parietal, and argentaffine cells as well as interstitial macrophages. The clinical symptoms consisted of increasing muscle weakness, cramps of the legs, and severe gastric pain that was resistant to treatment. Muscle biopsy specimens showed severe lipid storage in muscle fibers. Enzyme histochemistry revealed partial deficiency of cytochrome c oxidase (COX) with scattered non-reactive fibers among a majority of COX-positive fibers whereas biochemical analysis of muscle homogenates resulted in no corresponding defect of mitochondrial enzymes. Gastric biopsy specimens showed similarly to muscle fibers an extensive accumulation of lipid droplets in the chief cells, HCl producing parietal cells, macrophages, neutrophilic and eosinophilic leucocytes, and to a lesser degree also in argentaffine cells and unmyelinated axons of the gastric mucosa. The lipid droplets were associated with an insignificant increase in the number and size of mitochondria although paracristalline mitochondrial inclusions were neither noted in muscle fibers nor in cells of the gastric mucosa. These findings resemble those in multisystem triglyceride storage disease although the clinical signs were not reminiscent of this disease, and indicate that among the clinically heterogeneous group of cytochrome c oxidase deficiencies lipid storage may not be confined to muscle, but can affect the gastric mucosa as well.

Adult↗
PubMed1991

Threshold of detection of Cryptosporidium oocysts in human stool specimens: evidence for low sensitivity of current diagnostic methods.

To determine the minimum number of Cryptosporidium oocysts that can be detected in stool specimens by diagnostic procedures, stool samples seeded with known numbers of Cryptosporidium parvum oocysts were processed by the modified Formalin-ethyl acetate (FEA) stool concentration method. FEA concentrates were subsequently examined by both the modified cold Kinyoun acid-fast (AF) staining and fluorescein-tagged monoclonal antibody (immunofluorescence [IF]) techniques. Oocysts were more easily detected in watery diarrheal stool specimens than they were in formed stool specimens. For watery stool specimens, a 100% detection rate was accomplished at a concentration of 10,000 oocysts per g of stool by both the AF staining and IF techniques. In formed stool specimens, 100% of specimens seeded with 50,000 oocysts per gram of stool were detected by the IF technique, whereas 500,000 oocysts per g of stool were needed for a 100% detection rate by AF staining. Counting of all oocysts on IF slides indicated a mean oocyst loss ranging from 51.2 to 99.6%, depending on the stool consistency as determined by the FEA concentration procedure. Our findings suggest that the most commonly used coprodiagnostic techniques may fail to detect cryptosporidiosis in many immunocompromised and immunocompetent individuals.

Animals↗
PubMed1991

Exploring the doctor-patient relationship reduces staff stress and enhances empathy when caring for AIDS patients.

At our AIDS outpatient clinic we presently care for more than 1,200 HIV-infected patients. All physicians in this unit have participated for 1 year in a case work group supervised by a liaison psychiatrist. The doctor-patient relationship, the assessment in the case work group and the ensuing influence on perception and behavior are demonstrated by 3 cases. Different issues challenge the doctor-patient relationship: the serious prognosis of predominantly young AIDS patients; isolation and stigmatization of patients; fear of contagion, and questions of confidentiality regarding contact tracing. Reflection upon the doctor-patient relationship improves communication skills and increases empathy towards AIDS patients.

Acquired Immunodeficiency Syndrome↗
PubMed1991

The switch from larval to adult globin gene expression in Xenopus laevis is mediated by erythroid cells from distinct compartments.

The transition of hemoglobins during metamorphosis of Xenopus laevis involves replacement of the larval erythrocytes by adult ones, suggesting that the developmental control of this event depends upon the growth characteristics of the precursor cells. To identify the erythroid precursor cells and to investigate their developmental fate, we analyzed the distribution of stage-specific globin mRNAs by northern blotting in dorsal and ventral fragments of stage 32 embryos after in vitro culture as well as presumptive erythropoietic tissues of tadpoles during metamorphosis. The histological analysis shows that erythrocytes differentiate only in ventral fragments, suggesting that the ventral blood islands and most likely also the dorsolateral mesoderm are the primary sites of erythropoiesis. We also demonstrate that the first generations of erythrocytes, already express the predominating larval-specific alpha-globin mRNAs. The globin mRNA patterns obtained from presumptive erythropoietic tissues suggest an important role of circulating precursor cells in larval erythropoiesis, whereas the liver appears to be the main site of formation and maturation of the adult erythrocytes. Tentatively we propose that anuran erythropoiesis is dependent upon a self-perpetuating stem-cell line and that the larval and the adult erythrocytes are derived from successive generations of erythroid precursors, whose commitment may be imposed by the erythropoietic sites.

Animals↗
PubMed1991

[Secondary prevention in HIV infection].

In HIV seropositive persons, secondary prophylaxis should prevent HIV-associated diseases, including opportunistic and other complications, and delay progression of HIV infection. Efforts to control transmission of secondary infections are of limited value, since these complications are mainly caused by endogenous opportunistic microorganisms. Vaccines are currently available for only a few of the pathogens that are potentially important in this clinical setting; they include influenza, Streptococcus pneumoniae and hepatitis B. However, antibody responses to these vaccines may be unsatisfactory in immunocompromised persons. Chemoprophylactic regimens have been devised primarily for prevention of Pneumocystis carinii pneumonia and tuberculosis. Recently, antiretroviral therapy with zidovudine has shown promise in delaying progression of AIDS in asymptomatic HIV seropositive individuals with impaired cellular immunity.

Communicable Disease Control↗
PubMed1991

[Use of toltrazuril in pullet breeding flocks raised on floors with anticoccidial-free feed].

In 28 replacement pullet flocks with flock size of 4,000 to 25,000 birds Toltrazuril (experimental preparation, 2.5% solution, approx. 7 mg/kg body weight) was administered for a period of two days in the drinking water for metaphylactic purpose and therapeutic use, respectively. All flocks were reared without anticoccidial feed additives. Exposition to Eimeria spp. was recorded by examination of faecal samples and intestinal scrapings. Clinical flock control was achieved by vets at eight to ten day intervals. Toltrazuril was characterized by short application period, rapid mode of action, significant reduction of oocyst shedding, good compatibility and acceptance thus proving superior to conventional chemotherapy of coccidiosis. The results suggest that, even without administration of anticoccidial feed additives. Toltrazuril is an effective agent for therapeutic use in acute coccidiosis. Under insufficient management and rearing conditions repeated metaphylactic application has to be considered.

Animal Feed↗
PubMed1991

[Pregnancy and traffic accident. A case report].

The authors report the case of patient (second pregnancy, first birth) who had been involved in a traffic accident which occurred on October 5, 1989 after 7 months of pregnancy. The trauma was scored 2 on the international Overall Abbreviated Injury Scale. The impact was frontal and the patient driving and wearing her seatbelt. After being admitted to hospital on several occasions with metrorrhagia and uterine contractions, it was decided to carry out a cesarian and a baby was successfully removed. The child presented with angulation of the left fore-arm and skeletal X-ray, particularly of the arms, revealed a fracture line with a callous already formed.

Accidents, Traffic↗
PubMed1990

Progression of HIV infection in misusers of injected drugs who stop injecting or follow a programme of maintenance treatment with methadone.

OBJECTIVE: To see whether misusers of injected drugs who stop injecting or switch to a programme of maintenance treatment with methadone have a reduced risk of progression of HIV infection when compared with a group of persistent misusers. DESIGN: Observational cohort study in HIV seropositive subjects with a current or past history of misusing injected drugs. SETTING: HIV outpatient clinic at the University Hospital of Zurich, Switzerland. PATIENTS: 297 Current and former parenteral drug misusers (median age 27) with asymptomatic HIV infection. During the observation period 80 subjects adhered to a programme of maintenance treatment with methadone, 124 continued with parenteral drug misuse, and 93 former misusers remained free of illicit drugs. No antiretroviral treatment was given during the study. MAIN OUTCOME MEASURES: Probability of progression of HIV infection from asymptomatic to symptomatic (Centers for Disease Control stage IV) as calculated by life table analysis and compared in the three groups of patients by means of a log rank test, and predictors of disease progression as analysed with a Cox proportional hazards regression model. RESULTS: The 297 patients were followed up for a median of 16 months. The median duration of injecting drug misuse before enrollment was 7.1 years. There were no significant differences among the three groups with respect to CD4+ counts at the beginning of the study (median 0.44 x 10(9)/l). Life table analysis showed a significantly lower probability of progression of HIV disease in both the methadone treated group and former drug misusers than in persistent injecting drug misusers. Multivariate regression analysis showed a relative risk of progression of the disease of 1.78 (95% confidence interval 1.20 to 2.67; p less than 0.01) in persistent injecting drug misusers, 0.48 (0.29 to 0.77; p less than 0.01) in the methadone treated group, and 0.66 (0.41 to 1.06; p = 0.085) in former drug misusers. CONCLUSIONS: Stopping the misuse of injected drugs slows the progression of HIV disease in infected subjects. Drug treatment programmes are effective in secondary prevention of HIV associated morbidity.

Adult↗
PubMed1990

[Pneumocystis carinii pneumonia in HIV infection: better prognosis because of early diagnosis].

The clinical presentation of 60 consecutive Pneumocystis carinii pneumonias in 58 HIV-infected patients (48 men, 10 women, mean age 34 [22-53] years) was prospectively evaluated from April to August 1989 and compared with 60 consecutive P. carinii pneumonias in 59 HIV-infected patients (55 men, 4 women, mean age 37.5 [22-60] years) between 1981-88. Mortality rates within 14 days after diagnosis of P. carinii pneumonia were 50% (8 of 16 patients) until 1985, 20.5% (9 of 44) between 1986 and August 1988, and 1.7% (one of 60) in 1989. The degree of severity of the pneumonias at time of diagnosis was markedly lower in 1989, as shown by following parameters (averages of 1989, compared with averages of 1981-88): lactate dehydrogenase 540 (250-1419) U/l versus 680 (235-1920) U/l (not significant); alveolo-arterial difference of partial oxygen tension (pA-aO2) 22.9 (0.5-73.5) mmHg versus 39.7 (19-70) mmHg (P less than 0.001); score of radiological findings 1.4 (0-3) versus 2.7 (0-4) (P less than 0.001). In 1989, mainly clinical symptoms (dry cough: 57 of 60 cases, dyspnea: 44 of 60 cases, fever: 43 of 60 cases) initiated the diagnostic procedure: chest radiographs, lactate dehydrogenase and pA-aO2 were normal in 13, 25 and 33 episodes, respectively. The lower mortality rate of P. carinii pneumonia could not primarily be explained by therapeutical progress since the treatment of choice did not change fundamentally since 1981. Above all, early diagnosis fundamentally determined the probability of survival.

Adult↗
PubMed1990

Compliance and laboratory data predict relapse rate of Pneumocystis carinii pneumonia during prophylaxis with aerosol pentamidine.

We evaluated 43 AIDS patients on prophylaxis with aerosol pentamidine (60 mg biweekly) after Pneumocystis carinii pneumonia (PCP). The effects of patients' inhalation compliance and of laboratory data during the initial PCP on subsequent PCP relapses were assessed. After a median of 8 months (range, 2-21.5 months) on pentamidine prophylaxis, 13 patients suffered a PCP relapse. Six of them had missed at least one inhalation within the last month before the relapse. Two of these six relapses were fatal. The relapse occurrence was significantly associated with the percentage of missed inhalations. Additional significant associations were found between relapses, low levels of T4 lymphocytes, and elevated serum lactate dehydrogenase during the initial PCP episode (29 patients). Mean levels of T4 lymphocytes were 27/mm3 and 47/mm3 in patients with and without subsequent relapses, mean levels of lactate dehydrogenase were 692 U/L and 605 U/L, respectively. Multivariate Cox regression did not reveal further differences between patients with and without relapses. The increased relapse risk associated with poor inhalation compliance stresses the need for appropriate guidance and motivation of the patients.

Acquired Immunodeficiency Syndrome↗
PubMed1990

Nuclear polymorphism--a prognostic parameter to evaluate local recurrence of female breast cancer.

Between 1980 and 1986 676 patients underwent surgery for primary breast cancer. Of these, 35 patients developed locoregional recurrence. Retrospective analysis of the spontaneous postoperative development revealed 2 groups: group A had subsequent distant metastases, group B was tumor-free after surgical treatment of local recurrence. Analysis of the commonly employed characterization criteria of primary tumors (tumor size, lymph node involvement, estrogen receptors, histologic grading of primary tumors, and excised locoregional recurrence) showed no statistically significant difference between the two groups. However, a more detailed differentiation of the subcriteria for the histologic grading according to Bloom and Richardson revealed a prevalence of anaplastic nuclei in the primary tumors of group A (9/11). Even in this small patient population the parameter of nuclear polymorphism revealed a highly significant statistical difference between the two groups.

Austria↗