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Biomedical subjects

B Weber

Publications and source records attributed to B Weber.

At least 253 records · Page 14Linked to original sources
PubMed1994

Detection of herpes simplex virus DNA from cerebrospinal fluid by PCR and a rapid, nonradioactive hybridization technique.

A molecular assay for the detection of herpes simplex virus (HSV), including a novel, nonradioactive hybridization technique, was evaluated with a total of 123 cerebrospinal fluid specimens. After DNA extraction, specific HSV DNA sequences were amplified with digoxigenin-labeled primers derived from the DNA polymerase gene-coding region from HSV. Amplified products were detected by the Enzymun-Test DNA detection assay (Boehringer, Mannheim, Federal Republic of Germany), which uses biotinylated probes. Amplification with nonlabeled primers and then Southern blotting and nonradioactive detection of hybrids by the digoxigenin technique was the reference system. The sensitivities of the molecular assays were determined with 10-fold dilutions of plasmid pS4 with the SalI restriction fragment of the DNA polymerase gene obtained from the HSV type 1 strain Angelotti. The Enzymun assay was able to detect all of the 16 positive samples, giving 100% agreement with the Southern blot hybridization results. Optical density values were widely separated for the positive and negative groups of specimens. Ten copies of plasmid pS4 per microliter could be distinctly detected by the Enzymun assay. The cutoff was determined for the hybridization assay, and an equivocal zone was defined. The whole molecular assay including the Enzymun-Test DNA detection proved to be sensitive and easy to use. It may contribute to the rapid and safe detection of HSV DNA in cerebrospinal fluid.

Artifacts↗
PubMed1994

Failure of antiretroviral therapy: role of viral and cellular factors.

Effective therapy of human immunodeficiency virus (HIV) infection is mainly based on inhibition of reverse transcriptase by nucleoside analogues such as zidovudine (azidothymidine; AZT), didanosine, and zalcitabine. A major problem associated with long-term AZT therapy is the waning efficacy ('clinical resistance') over time. Clinical isolates of HIV-1 with reduced susceptibility to AZT can be recovered from HIV-infected individuals under prolonged treatment. However, the clinical importance of AZT resistance is uncertain. Other factors such as increased virus burden, increased virulence, and AZT toxicity could contribute, singly or in combination, to the loss of therapeutic benefit. Recent observations based on experimental models and clinical trials suggest that cellular mechanisms ('cellular resistance') may account for clinical resistance to antiviral agents. In vitro experiments demonstrated that in analogy to antitumoral therapy, the acquisition of multidrug resistance, i.e., resistance of cells to multiple, structurally unrelated chemotherapeutic agents, may play a role in the failure of long-term antiretroviral therapy. The 'cellular resistance' may contribute directly to the failure of antiviral therapy by the generation of subtherapeutic levels of antiviral compounds and/or their active forms. Indirectly, such subtherapeutic concentrations of active substances which permit limited replication of virus may represent a selective pressure for emergence and development of a resistant virus population. Hence it is of great importance to investigate the role of cellular factors in 'clinical resistance' to AZT and other anti-HIV agents. More detailed knowledge of cellular interactions and antiviral agents could help to improve or develop new strategies for antiviral therapy regimens.

Antiviral Agents↗
PubMed1994

Suspension culture of HeLa cells in protein-free medium: sensitivity to human pathogenic viruses.

Human adherent HeLa-PF cells grown for 5 years in a protein-free 1:1 nutrient mixture of Dulbecco's modified MEM and Ham's F12 (DMEM-F12) were established in suspension culture. The cells grew in protein-free DMEM-F12 (using magnetically stirred flasks) as a monodisperse suspension with a population doubling time of 28 h. The cells were infected with poliovirus types 2 and 3, herpes simplex virus types 1 and 2 (HSV-1 and HSV-2), respiratory syncytial virus (RSV), echovirus 6 and adenoviruses 3 and 7. Polioviruses replicated in suspension culture of HeLa-PF cells to a similar extent as in protein-free and serum-supplemented adherent cultures. RSV and HSV developed significantly lower titers while adenoviruses and echovirus 6 developed significantly higher titers in suspension than in adherent cultures. The results show that suspension culture of HeLa-PF may both provide the advantage of a high virus yield and enable cultivation of viruses which are not contaminated by serum or other proteins usually added to the culture medium.

Cell Culture Techniques↗
PubMed1994

Detection of primary HIV infection by a second-generation HIV(p24) antigen test.

We studied the course of a primary HIV infection in a 54-year-old woman. Probably the source of infection was sexual intercourse, since other risks, such as i.v. drug use, acupuncture and transfusion were excluded. On admission she presented with fever, a maculopapular rash, and moderate enlargement of nuchal lymph nodes. At that time the anti-HIV 1,2 enzyme immunoassay was negative. However, the HIV-p24 Ag test, which was performed in every HIV screening in our laboratory, was positive. The suspicion of an acute HIV infection was supported by a positive HIV-cDNA-PCR and confirmed by Western blot after seroconversion. As additional finding, the blood smear showed abnormal white cell differential count, indicating viral infection. Aminotransferases were slightly increased, and antibodies to hepatitis B surface and core antigens demonstrated former hepatitis B infection. It is concluded that in this case the HIV-p24 Ag test proved its suitability for early diagnosis of an acute HIV infection. In case of testing blood donors, none of the compulsory serological screening methods would have detected the HIV infection.

AIDS Serodiagnosis↗
PubMed1994

Diagnosis and epidemiology of transfusion-associated human cytomegalovirus infection: recent developments.

OBJECTIVE: The prevention and diagnosis of transfusion-associated HCMV infection has to address different questions: Is the blood donor potentially infections? Is the transfused recipient undergoing an active primary or secondary infection? DATA SOURCES: International literature (Current Contents Life Sciences) and reports of our study-group. SELECTION CRITERIA: Original articles in English and German. RESULTS: Monocytes have been identified as the major site of latency of human cytomegalovirus (HCMV) in peripheral blood. High seropositivity rates are observed in polytransfused individuals, intravenous drug users, organ transplant recipients, maintenance hemodialysis patients, homo/bisexuals and prostitutes. Although, there have been important developments in order to improve the sensitivity of the ELISAs for the diagnosis of active HCMV infection, serologic testing often fails to detect IgM and IgA antibodies in immunocompromised patients. Rapid virus isolation, structural antigen detection and DNA amplification by PCR in peripheral blood monocytes have considerably improved diagnosis of acute HCMV infection in neonates, organ transplant recipients and AIDS patients. Due to the low correlation of HCMV DNA detection and HCMV disease, PCR testing is actually not recommended for the monitoring of high risk patients and screening of infectiosity of blood components. CONCLUSIONS: As a consequence numerous improvements in serological, virological and molecular methods, a more efficient prevention and diagnosis of transfusion-associated HCMV infection has become possible.

Blood Donors↗
PubMed1994

Long-term glycemic control has a nonlinear association to the frequency of background retinopathy in adolescents with diabetes. Follow-up of the Berlin Retinopathy Study.

OBJECTIVE: To assess the influence of long-term glycemic control on the development of background retinopathy in adolescents followed longitudinally from the onset of insulin-dependent diabetes mellitus (IDDM). RESEARCH DESIGN AND METHODS: Repeated retinal fluorescein angiographies, in intervals of 1-2 years, were evaluated prospectively in 346 patients (190 males, 156 females; 19.8 [8.8-35.4] years of age; diabetes duration of 10.4 [1.1-27.4] years at their latest eye examination, median [range]). The influences of long-term HbA1c (mean of 18 [1-95] determinations per person) and microalbuminuria (> or = 2 of > or = 3 measurements > or = 15 micrograms/min x 1.73 m2) were studied by multiple linear regression, life-table analysis, and trend analyses. RESULTS: The rate of background retinopathy per 100 patient-years increased with poorer glycemic control from 0.7 (long-term HbA1c < 7% to 7.3 (HbA1c > 11%) following an exponential function. Life-table analysis after subdivision in HbA1c quartiles of equal sizes (HbA1c < 8, 8-9, 9-10, and > 10%) revealed an individual median expectation of background retinopathy after more than 25, 16.2, 12.7, or 12.0 years of diabetes, respectively. However, significant differences were found only between 8-9% and 9-10%, calculated either as prevalence, life-table analysis, or relative incidence, thus suggesting that a threshold model may also fit the data. After 12 years of diabetes, < 25% of those patients exhibiting microalbuminuria (n = 18) were expected to be free from retinopathy compared with 81% of those with normoalbuminuria (n = 86). CONCLUSIONS: Two statistical models are appropriate to explain the relationship between glycemic control and risk for background retinopathy: 1) a continuous exponential relationship as described by the DCCT or 2) the presence of a threshold HbA1c level at 9%. Thus, diabetes treatment in children should aim at long-term HbA1c levels < 9.0%, but every progress closer to normal may further reduce the risk.

Adolescent↗
PubMed1994

Linear loss of insulin secretory capacity during the last six months preceding IDDM. No effect of antiedematous therapy with ketotifen.

OBJECTIVE: To investigate the effect of an antiedematous therapy with the histamine antagonist ketotifen on beta-cell function in late prediabetes. RESEARCH DESIGN AND METHODS: In a randomized double-blind placebo-controlled study, ketotifen was administered for 3 months to 9 islet cell antibody positive (ICA+) prediabetic patients with a first-phase insulin response (FPIR) below the 2.5th percentile to preserve residual beta-cell function. Patients were followed by intravenous glucose tolerance tests (IVGTTs) every 4-6 weeks for determination of FPIR, HbA1, ICAs, and insulin autoantibodies. In 5 patients, the immune activation state was followed by determination of serum levels of tumor necrosis factor-alpha (TNF-alpha), beta 2-microglobulin, and C-reactive protein (CRP). RESULTS: Seven of nine patients developed diabetes within one year of follow-up. Irrespective of treatment with ketotifen, a slow and linear decline (P < 0.05) of 1 + 3-min insulin values was observed in sequential IVGTTs in those 7 patients who developed insulin-dependent diabetes mellitus (IDDM) during follow-up. The 2 other patients showed wide fluctuations of the insulin response with a threefold increase of initial insulin levels. HbA1 did not correlate with FPIR. Fasting blood glucose increased significantly during the study (P < 0.05). Individual levels of serum TNF-alpha, CRP, and beta 2-microglobulin did not change during the study. CONCLUSIONS: The study could not demonstrate preservation of beta-cell function by ketotifen in the late stage before manifestation of clinical diabetes. Manifestation is preceded in the last 6 months by a steady loss of the FPIR without rapid deterioration immediately before diagnosis and without signs of increased immune activity.

Adolescent↗
PubMed1994

Cost of unsuccessful surgery for primary hyperparathyroidism.

BACKGROUND: Surgery for primary hyperparathyroidism demands skill and experience. The monetary and personal costs of unsuccessful surgery are investigated here. METHODS: We reviewed 47 consecutive patients operated on by one surgeon during a period of 16 months, including their clinical data and medical costs of their treatment. RESULTS: All 39 patients without previous operation were normocalcemic after operation, with no recurrent nerve injury nor hypoparathyroidism. Of the eight who had undergone previous operation elsewhere, seven had abnormal glands that should have been resected at the initial operation, and hypoparathyroidism developed in two patients. Total costs of reoperative parathyroid surgery were more than twice the cost of an initial operation (median, $8383 versus $3948, p < 0.001) because of the cost of radiologic studies (median, $3378 versus $43, p < 0.001). CONCLUSIONS: (1) An experienced parathyroid surgeon can consistently cure hyperparathyroidism at the initial operation. (2) The majority of patients referred for hyperparathyroidism not cured by previous operation have glands in usual anatomic locations. (3) The cost to the patient of an inadequate initial operation includes the physical effects of remaining hyperparathyroid, additional time off work, potentially invasive localization testing, reoperative surgery with increased risk of complications, and substantial expense. Initial parathyroid surgery should be performed by surgeons experienced and proficient in its practice.

Adult↗
PubMed1993

[Incidence of Lyme borreliosis in a rheumatologic patient sample. Study of 153 patients of an internal medicine-rheumatologic ambulatory clinic].

PROBLEM: Arthritis of the large joints is considered a typical manifestation of Lyme disease. With an estimated incidence in the population of about 2%, Lyme disease arthritis would be expected to be a fairly common diagnosis in a rheumatology unit. METHODS: In 153 successive patients seen in a rheumatology clinic of the University Hospital Frankfurt am Main, who had historical or clinical evidence of arthritis, the IgG antibody titers against Borrelia burgdorferi in the serum were compared with the clinical presentation. RESULTS: Twelve patients had positive or borderline positive antibodies titers. In three of the 153 patients, the diagnosis of Lyme disease-associated arthritis appears possible, although not probable. CONCLUSIONS: At least in the greater area of Frankfurt, Lyme disease as a differential diagnosis of arthritis is apparently of no great significance.

Adolescent↗
PubMed1993

Detection of neutralizing antibodies against human cytomegalovirus: influence of strain variation.

The influence of human cytomegalovirus (HCMV) strain variation on neutralizing antibody titers was investigated in sequential sera obtained from 12 organ transplant recipients (11 renal transplant recipients, 1 liver transplant patient) suffering from primary or secondary HCMV infection. Cross-neutralization assays using either the international HCMV reference strain AD169 or individual clinical isolates from patients showed congruent results. Restriction enzyme analysis of the hypervariable alpha-sequence of the L-S junction of AD169 and HCMV isolates amplified by polymerase chain reaction (PCR) were carried out to confirm the expected strain differences. At least 6 groups of clinical strains were differentiated. The results of this study demonstrated that despite the strain heterogenicity of HCMV, the neutralization assay using AD169 permitted a reliable and quantitative serologic detection of neutralizing antibodies against HCMV.

Antibodies, Viral↗
PubMed1993

Humoral immune response to human cytomegalovirus infection: diagnostic potential of immunoglobulin class and IgG subclass antibody response to human cytomegalovirus early and late antigens.

For the development of effective prophylaxis (hyperimmune globulins) and improvement of serological testing for human cytomegalovirus (HCMV) infection in immunocompromised patients it is essential to characterize the viral encoded proteins and the humoral immune response in terms of neutralizing antibodies and immunoglobulin class and IgG subclass reactivity to "early" and "late" HCMV proteins. The major neutralizing epitopes have been identified and screening of donor sera for neutralizing antibody by either conventional neutralization assays or enzyme-linked immunosorbent assay using recombinant antigens may help to improve the efficacy of hyperimmune globulin prophylaxis. The humoral response to individual HCMV proteins has been thoroughly investigated in immunocompromised patients. Antibodies against HCMV induced "early" antigens are not exclusively associated with active infection but may indicate an elevated risk for cytomegalic inclusion disease in immunocompromised patients. With a sensitive western blot technique. IgM and IgA antibodies against HCMV "late" proteins can be detected in sera from healthy seropositive individuals. Serum samples from subjects suffering from cytomegalic inclusion disease show significantly larger broader immune responses compared with healthy HCMV antibody carriers. Promising results using recombinant antigens corresponding to immunodominant epitopes for the detection of HCMV specific antibodies have been published.

Antibodies, Viral↗
PubMed1993

Sequence-dependent growth-inhibitory effects of the in vitro combination of fluorouracil, cisplatin, and dipyridamole.

The present study was designed to analyze the growth-inhibitory effects of the combination of fluorouracil (FUra), cisplatin (CDDP), and dipyridamole (DP). These toxic effects were assessed on the human breast-carcinoma cell line MCF-7 using the MTT (tetrazolium bromide) assay in 96-well culture dishes. Data were analyzed using the median-effect principle. The drug combinations tested included FUra concentrations ranging from 0.8 to 800 nmol/l, CDDP concentrations of 0.3-30 mumol/l, and DP concentrations of 2-200 mumol/l. A total of 189 different experimental conditions were tested, including different sequences of administration, with being DP applied before, simultaneously with, or after the two antitumor drugs. Synergistic cytotoxic interactions were found between FUra and CDDP, FUra and DP, and CDDP and DP as well as when the three drugs were combined. The sequence of exposure did not influence the growth-inhibitory activity of the combination FUra-CDDP but altered the effect of combinations of either FUra or CDDP with DP, since at lower concentrations the effect shifted from synergism to antagonism when DP was added simultaneously with CDDP and after the two antitumor drugs. However, the interaction was shown to be truly synergistic by median-effect analysis when the two antitumor drugs were simultaneously associated, with no change in the synergistic effect being observed for the three DP administration sequences.

Adenocarcinoma↗
PubMed1993

Retained fetal lung liquid in congenital lobar emphysema: a possible predictor of polyalveolar lobe.

The purpose of this study was to determine whether retention of fetal lung liquid is more prevalent in polyalveolar congenital lobar emphysema than in conventional congenital lobar emphysema. Two patients with congenital lobar emphysema were prospectively identified in a 3-year period. Twenty-five such patients were identified in a retrospective study covering 39 years. Medical records were available for 22 patients who had 23 emphysematous lobes. Both babies from the prospective study and six subjects from the retrospective group had respiratory symptoms and underwent chest X-ray in the first day of life. Six of the eight babies with respiratory symptoms and chest imaging in the first day of life had retention of fetal lung liquid in an emphysematous lobe. All six of these lobes were polyalveolar. The lobe in one child was a polyalveolar lobe but without retained fetal lung liquid, and one child exhibited conventional lobar emphysema also without retained fetal lung liquid. One polyalveolar lobe caused no neonatal symptoms and was not imaged until the child was 3 months old. No baby with conventional lobar emphysema was shown to have retained fetal lung liquid. There seems to be a correlation between polyalveolar lobe and onset of respiratory symptoms in the first day of life. Retention of fetal lung liquid within the affected lobe was documented only in cases of polyalveolar lobe.

Female↗
PubMed1993

Evaluation of the automated 'Enzymen-Test Anti HIV-1 + 2' and 'Enzymen-Test Anti HIV-1/2 selective' for the combined detection and differentiation of anti-HIV-1 and anti-HIV-2 antibodies.

A new, modular automated ELISA (test 1) for HIV-1 and HIV-2 antibody detection and differentiation (Enzymun-Test Anti HIV-1 + 2; anti HIV 1/2 selective, Boehringer Mannheim) was compared with 3 alternative enzyme immunoassays (Abbott recombinant HIV-1/HIV-2 3rd generation EIA, Abbott (test 2); Enzygnost HIV 1 + 2, Behringwerke (test 3); and Wellcozyme HIV recombinant, Murex (test 4)) and Western blot (New LAV I Blot and New LAV II Blot; Diagnostics Pasteur). 380 serum samples from HIV-1 and HIV-2 seropositive patients at different stages of disease, high risk individuals, patients with conditions unrelated to AIDS and from healthy blood donors were used in this evaluation along with 6 seroconversion panels, 6 serum dilution series and 'tricky' sera (repeatedly positive results in ELISA, but negative or undeterminate in Western blot; n = 67). Using the Western blot as reference assay, the overall sensitivity of the four ELISAs was 100%. Test 4 showed the highest sensitivity for antibody detection in seroconversion and dilution series. A high specificity was achieved with test 1 (100%) and test 2 (99.4%). A relatively high rate of false positive results were obtained with test 2 (n = 12) and test 3 (n = 10) by testing 'tricky' sera or samples obtained from healthy blood donors. In comparison to Western blot, a clear differentiation between HIV-1 and HIV-2 antibody serum samples was achieved with the Enzymun-Test. The results of the present study show that the Enzymun-Test provides reliable selective HIV-1 and HIV-2 antibody detection at a cost which is significantly lower than the costs of Western blot tests. Furthermore, the evaluation of test 1 suggests, that it is a highly specific assay for HIV antibody detection.

AIDS Serodiagnosis↗
PubMed1993

Immunoglobulin A and M patterns to human cytomegalovirus during recurrent infection in patients with AIDS using a modified western blot.

Immunoglobulin A and M patterns to human cytomegalovirus (HCMV) were investigated in sera from actively HCMV infected AIDS patients (n = 61) and healthy HCMV seropositive controls (n = 28) by a Western blot method (modi-blotting) and ELISA. The Western blot showed a higher detection rate for both IgA (78.7% vs. 52.5%) and IgM (83.6% vs. 13.1%) than ELISA in the immunocompromised patients suffering from active HCMV infection. Of the healthy seropositive individuals, 35.7% and 21.4% had a weak positive IgA- and IgM-class antibody reactivity respectively with HCMV-specific bands in the immunoblot. Immunoglobulins M and A were not detected by ELISA in the healthy control group. Immunoreactions in this group were restricted to viral polypeptides with M(r) of 68 kDa and 123 kDa. Additional bands were found in the actively infected patients only and were observed more frequently with IgA than IgM (47.5% vs. 29.5%). Results from the present study indicate, that using a sensitive Western blot technique, a higher serologic detection rate of active recurrent infection is achieved in AIDS patients. Nevertheless, immunoglobulin A and M are detected in a certain percentage of HCMV-seropositive healthy individuals not suffering from active HCMV infection. Broader immune reactions of HCMV-IgA as determined by HCMV Western blot assay are associated with an active infection, but were not present in all the actively infected patients.

Acquired Immunodeficiency Syndrome↗
PubMed1993

Evaluation of the automated VIDAS system for the detection of anti-HIV-1 and anti-HIV-2 antibodies.

A new, modular 'walk away' system for HIV 1 and HIV 2 antibody detection (VIDAS HIV 1 + 2 enzyme linked fluorescent assay) was compared with EIAs (Wellcozyme HIV recombinant, Wellcome; and Enzygnost HIV 1 + 2, Behringwerke) and Western blot (New LAV I Blot; Pasteur). 434 serum samples from HIV seropositive patients at different stages of disease, individuals at high risk, patients with conditions unrelated to AIDS and healthy blood donors were used for this evaluation together with 4 seroconversion panels, 4 serum dilution series and 'difficult' sera (repeatedly positive results in EIA, but negative or indeterminate by Western blot; n = 87). With the Western blot as the reference assay, the overall sensitivity of VIDAS HIV 1 + 2 and the alternative EIAs was 100%. Significant differences in sensitivity between the 3 EIAs were not observed for the antibody detection in the seroconversion panels and the dilution series. The specificity of VIDAS HIV 1 + 2, Enzygnost and Wellcozyme were 93.5%, 89.6% and 92.4% respectively if Western blot strips were interpreted according to CDC-criteria. A high rate of false positive results was obtained with the 3 EIAs since serum samples were not selected randomly and a large collective of 'difficult sera' was investigated. So-called 'walk away' systems like VIDAS HIV 1 + 2 offer a rapid screening for HIV antibody detection for routine laboratory diagnosis.

Acquired Immunodeficiency Syndrome↗
PubMed1993

Expression of CD44 isoforms carrying metastasis-associated sequences in newborn and adult rats.

Expression of a splice variant of CD44, recognised by the monoclonal antibody (Mab) 1.1ASML, confers metastatic potential to non-metastasising tumour cells (Cell 1991, 65, 13-24). To explore whether the metastasis-associated variant of CD44 (CD44v) is expressed under physiological conditions, tissues of newborn and adult rats were stained with the Mab 1.1ASML. The 1.1ASML epitope is, indeed, expressed on the basal layer of the epidermis and the hair follicles as well as on cryptic epithelia in the gut. In addition, ductal epithelia of the pancreatic gland of newborn rats express CD44v. This pattern of expression differs from that of standard lymphocyte CD44 (CD44s). The anti-CD44s mAB Ox50 predominantly stains connective tissue. Although different variants of CD44 may express the epitope recognised by 1.1ASML, cells expressing CD44v share properties with metastasising tumour cells: the stage of proliferation and a restricted degree of mobility. Thus, during metastatic progression tumour cells may reactivate the expression of gene segments which serve highly specialised functions in embryonic and adult tissues.

Aging↗