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Biomedical subjects

B Weber

Publications and source records attributed to B Weber.

At least 199 records · Page 11Linked to original sources
PubMed1996

In vitro inhibition of human cytomegalovirus replication by calcium trinatrium diethylenetriaminepentaacetic acid.

Desferrioxamine (DFO) has been shown to inhibit human cytomegalovirus (CMV) replication in vitro. In the present study, we compared antiviral effects of DFO in human foreskin fibroblast (HFF) cells against several CMV strains with those of other chelators that interact with iron and other ions from different pools. DFO, a hydrophilic chelator, that may chelate both intracellular and extracellular ions inhibited production of CMV late antigen at 50% effective concentrations (EC50S) ranging from 6.2 to 8.9 microM. EC50S for calcium trinatrium diethylenetriaminepentaacetic acid (CaDTPA) ranged from 6.1 to 9.9 microM. EC50S for 2,2'-bipyridine (BPD), a hydrophobic chelator, which diffuses into cell membranes ranged from 65 to 72 microM. Concentrations which inhibited BrdU incorporation into cellular DNA by 50% (IC50S) ranged from 8.2 to 12.0 microM (DFO), from 65 to 89 microM (BPD), and from 139 to 249 microM (CaDTPA). CaDTPA was the only chelator which completely inhibited production of infectious virus in HFF and vascular endothelial cells at concentrations which had no significant effects on cellular DNA synthesis and growth. Addition of stoichiometric amounts of Fe3+ in the culture medium of HFF cells completely eliminated antiviral effects of DFO while antiviral effects of CaDTPA and BPD were only moderately affected. Fe2+ and Cu2+ were stronger inhibitors of CaDTPA than Fe3+; however, Mn2+ and Zn2+ completely suppressed antiviral effects of CaDTPA. The results show that CaDTPA is a novel nontoxic inhibitor of CMV replication. The antiviral activity of CaDTPA is suppressed by metal ions with a decreasing potency order of Mn2+/Zn2+ > Fe2+ > Cu2+ > Fe3+.

2,2'-Dipyridyl↗
PubMed1996

Identification of a 60 kd cross-reactive allergen in pollen and plant-derived food.

BACKGROUND: Cross-reactive IgE antibodies were found to be responsible for allergic reactions in patients allergic to pollen on ingestion of food (oral allergy syndrome). So far, the major birch pollen allergen Bet v 1 and birch profilin (Bet v 2) were identified as relevant cross-reactive allergens. OBJECTIVE: In this study we attempted to identify additional cross-reactive plant allergens, which could be responsible for food intolerance in patients allergic to pollen. METHODS: Monoclonal antibodies specific for the major mugwort pollen allergen, Art v 1, representing a 60 kd glycoprotein, were used to detect cross-reactive allergens in other pollens and plant-derived food. The amino acid compositions of the cross-reactive structures were determined, and their resistance against trypsin treatment was investigated. In addition, IgE immunoblot inhibitions were done with the 60 kd mugwort pollen allergen. RESULTS: Monoclonal antibodies specific for the major mugwort pollen allergen, Art v 1, cross-reacted with proteins of comparable molecular weight in fruit and vegetables. Preadsorption of patients' sera with the 60 kd mugwort allergen led to a reduction of IgE binding to components of a similar molecular weight present in different pollen (birch, timothy grass), fruit (apple, peanuts), and vegetable (celery) extracts and reduced IgE binding to apple, kiwi, and celery as determined by RAST inhibitions. CONCLUSION: A cross-reactive plant panallergen, possibly identical to the major mugwort pollen allergen, Art v 1, is described. The allergen represents a protein of approximately 60 kd present in various pollen and plant foods; which is distinct from Bet v 1 and profilin and hence may represent a novel cross-reactive allergen in the oral allergy syndrome.

Allergens↗
PubMed1996

Corticosteroid-binding globulin is not decreased in depressed patients.

We studied corticosteroid-binding globulin (CBG) in 25 drug-free depressed patients and 33 healthy controls over a wide age-range. CBG was measured at 0800, 1400, 2000 and 2400 h in all subjects. Analysis of variance (ANOVA) with repeated measurement design revealed a significant effect of gender and time, but not of diagnosis (depressed patients vs healthy controls) or age group (< 50/> 50 years). In females, regardless of diagnosis, CBG plasma concentrations were significantly increased, when compared with their male counterparts. Although as a group depressed patients had significantly higher plasma cortisol concentrations (108.0 +/- 23.1 vs 70.7 +/- 10.9 micrograms/l), CBG levels did not differ between the two groups. Thus we did not find hypercortisolemia in depression to be paralleled by a decrease in CBG. However, the exaggerated activity of the hypothalamus-pituitary-adrenocortical system in healthy and depressed females is associated with an increase in plasma CBG.

Adult↗
PubMed1996

The complete BRCA2 gene and mutations in chromosome 13q-linked kindreds.

Breast carcinoma is the most common malignancy among women in developed countries. Because family history remains the strongest single predictor of breast cancer risk, attention has focused on the role of highly penetrant, dominantly inherited genes in cancer-prone kindreds (1). BRCA1 was localized to chromosome 17 through analysis of a set of high-risk kindreds (2), and then identified four years later by a positional cloning strategy (3). BRCA2 was mapped to chromosomal 13q at about the same time (4). Just fifteen months later, Wooster et al. (5) reported a partial BRCA2 sequence and six mutations predicted to cause truncation of the BRCA2 protein. While these findings provide strong evidence that the identified gene corresponds to BRCA2, only two thirds of the coding sequence and 8 out of 27 exons were isolated and screened; consequently, several questions remained unanswered regarding the nature of BRCA2 and the frequency of mutations in 13q-linked families. We have now determined the complete coding sequence and exonic structure of BRCA2 (GenBank accession #U43746), and examined its pattern of expression. Here, we provide sequences for a set of PCR primers sufficient to screen the entire coding sequence of BRCA2 using genomic DNA. We also report a mutational analysis of BRCA2 in families selected on the basis of linkage analysis and/or the presence of one or more cases of male breast cancer. Together with the specific mutations described previously, our data provide preliminary insight into the BRCA2 mutation profile.

BRCA2 Protein↗
PubMed1996

Transient expression of CD44 variant isoforms in the ontogeny of the rat: ectoderm-, endoderm- and mesoderm-derived cells express different exon combinations.

Expression on rat tumor cells of CD44 variant isoforms containing exons v4-v7 or v6-v7 has been described as sufficient for initiation of the metastatic cascade. The question arose as to whether physiological programs may be reactivated by particular CD44 isoforms. With this in mind, expression of mRNAs for the CD44 isoforms was surveyed during ontogeny of the rat. Using available monoclonal antibodies, expression of the CD44 standard isoform (CD44s) and of an epitope of CD44 exon v6 (CD44v6) were evaluated by immunohistology also. While CD44s was expressed in cells of all three germ layers, CD44v6 expression was restricted to distinct epithelial layers and cells of the hematopoietic system. During ontogeny, expression of CD44v6 was first noted in the neural tube and the leading epithelial layer of the limb buds. Later, anti-CD44v6 (1.1ASML) stained basal layers of the epidermis, the epithelium of the gut, and the acini of the submandibular gland. Strong, but transient expression of CD44v6 was seen during lung development, in hematopoietic stem cells of the liver, in thymic epithelia and early thymic immigrants. Expression in these organs was downregulated shortly before or after birth. As revealed by Southern blotting after use of the reverse transcriptase polymerase chain reaction (RT-PCR), most CD44v6-positive organs contained more than one CD44 variant isoform, and the expression patterns differed between individual organs. Hematopoietic cells preferentially expressed exons v4-v7, endodermal tissue exons v4-v10 and only in the epidermis were exons v1-v10 detected. The temporally regulated expression during ontogeny and the different exon compositions suggest a pivotal role of CD44 isoforms particularly in hematopoesis and in pattern formation by instructive epithelia.

Animals↗
PubMed1996

Plasma leptin in depressed patients and healthy controls.

Leptin is known to regulate food intake and energy expenditure. Since loss of appetite and bodyweight are important signs and symptoms of major depression we studied leptin plasma concentrations in both depressed patients (n = 24) suffering from loss of appetite and a healthy control group (n = 33). To rule out the possibility of inferences with other endocrine parameters known to be changed in depression or suspected to be related to leptin, we also studied cortisol, insulin, growth hormone (GH) and GH-binding protein (GHBP). We found that leptin plasma concentrations did not differ between depressed patients and healthy controls. However, leptin was positively associated with female gender, body mass index (BMI) and morning insulin. 24-hour mean cortisol was not related to leptin. Also, GH and GHBP were not related to leptin when controlled for BMI in an ANCOVA model. We conclude that leptin plasma concentrations are unchanged in depression and that there is no evidence for leptin playing a major role in loss of appetite and body weight in depressed patients.

Adult↗
PubMed1996

Cloning and expression of the gene involved in Sanfilippo B syndrome (mucopolysaccharidosis III B).

Sanfilippo B syndrome is caused by a deficiency of alpha-N-acetylglucosaminidase, a lysosomal enzyme involved in the degradation of heparan sulphate. Accumulation of the substrate in lysosomes results in degeneration of the central nervous system with progressive dementia often combined with hyperactivity and aggressive behaviour. In order to clone the deficient gene, we purified the enzyme from human placenta and obtained amino acid sequence information. Alignment of one of the CNBr generated internal peptides to sequence from the database revealed the chromosomal location of the gene in the 5' upstream flanking region of the gene for 17-beta-hydroxysteroid-dehydrogenase at 17q21.1. The available DNA sequence was used to clone the cDNA coding for alpha-N-acetylglucosaminidase and analyse its gene structure. The gene is fully contained in the 5' upstream flanking region of the gene for 17-beta-hydroxysteroid-dehydrogenase and interrupted by five introns. The cDNA clone has a length of 2575 bp and encodes a protein of 743 amino acids. Chinese hamster ovary cells transfected with the cDNA construct show alpha-N-acetylglucosaminidase activity about 17-fold over background. This will allow correction studies with NAG deficient Sanfilippo B cell lines and facilitate the development of enzyme replacement therapy for these patients.

Acetylglucosaminidase↗
PubMed1996

Mammographically detected breast cancer. Benefits of stereotactic core versus wire localization biopsy.

OBJECTIVE: The authors evaluated the differences between stereotactic core needle biopsy (SCNBx) and needle localization surgical biopsy (NLBx) in cost and treatment course for patients with mammographically detected breast cancer. SUMMARY BACKGROUND DATA: Stereotactic core needle breast biopsy is a reproducible and reliable alternative to surgical biopsy for histologic diagnosis of mammographic lesions. METHODS: Records from 52 consecutive patients with invasive breast cancer diagnosed by SCNBx (n = 21) or NLBx (n = 31) over 2 years were reviewed. Episode-of-care costs were extracted from the Barnes Hospital billing system database. RESULTS: At the time of excision, surgical margins were statistically more frequently positive in patients treated with NLBx (55%) than patients treated with SCNBx (0%, p < 0.0001). Furthermore, patients in the NLBx group undergoing breast conservation surgery required re-excision more frequently (74%) than those in the SCNBx group (0%, p = 0.001). There were no complications in either group after the diagnostic procedure. All SCNBx results were correct in the diagnosis of invasive breast cancer. The median cost of SCNBx was approximately $1000 less than the median cost of NLBx. This cost difference was carried through the definitive procedure, whether it was breast conservation or mastectomy. CONCLUSIONS: This study shows the advantage of SCNBx to diagnose breast cancer and definitive operative care at a single procedure. The preoperative diagnosis of breast cancer eliminated positive operative margins and procedures to re-excise breast tissue. The use of SCNBx also saved approximately $1000 per patient compared with the use of NLBx. Our data suggest that SCNBx is the diagnostic procedure of choice for mammographically detected cancers.

Adenocarcinoma↗
PubMed1996

Lipid profiles and blood pressure: are they risk factors for the development of early background retinopathy and incipient nephropathy in children with insulin-dependent diabetes mellitus?

The objective of this study is to examine the influence of lipid profiles and blood pressure on the development of microvascular complications in adolescents with insulin-dependent diabetes mellitus (IDDM) in a matched pairs study. Patients with early background retinopathy (n = 21) or microalbuminuria (n = 15) and their respective statistical twins participated in the study. Serum total cholesterol, high-density lipoprotein (HDL) cholesterol, fasting triglycerides, glycosylated haemoglobin A1c (HbA1c), and systolic and diastolic blood pressure during 3 years prior to the development of early background retinopathy or incipient nephropathy were examined. The multivariate discriminant analysis demonstrated glycaemic control and HDL cholesterol to be the most important variables related to the development of retinal lesions (84% correctness), and diastolic blood pressure to be associated with microalbuminuria (57% correctness). In addition to poor glycaemic control, different factors seem to be important for the early retinal or renal lesions of juvenile IDDM.

Adolescent↗
PubMed1996

New PCR assay for rapid and quantitative detection of human cytomegalovirus in cerebrospinal fluid.

Rapid Chelex extraction combined with an automated hybridization assay for the detection of PCR-amplified human cytomegalovirus DNA from cerebrospinal fluid was established. Quantitation of DNA was performed with a plasmid being used as an external standard. The detection limit was 10 copies per microliter. Quantitative detection of human cytomegalovirus DNA could be achieved over a range from 10 to 10(4) copies per microliter.

AIDS-Related Opportunistic Infections↗
PubMed1996

Quantitative detection of human immunodeficiency virus (HIV) antigen by the Enzymun-Test: comparison with alternative assays and nucleic acid sequence-based amplification of HIV type 1 RNA.

A new modular automated enzyme immunoassay (EIA) (Enzymun-Test HIV Ag: Boehringer Mannheim) for quantitative human immunodeficiency virus (HIV) antigen detection was evaluated by testing a panel of 1,506 serum samples, including seroconversions, dilution series, follow-up samples from patients under antiretroviral therapy, single serum specimens from HIV-seropositive individuals in different stages of infection, potentially cross-reactive samples, and sera from HIV-negative hospitalized patients. The Abbott HIV type 1 (HIV-1) antigen monoclonal antibody assay served as the reference assay, and nucleic acid sequence-based amplification (Organon Teknika) for quantitative amplification of HIV-1 RNA was used for follow-up of patients under antiretroviral chemotherapy. The Boehringer Mannheim and Abbott EIAs showed concordant results for the early detection of HIV antigen in all the seroconversion panels. The follow-up samples from 29 HIV-infected individuals under antiretroviral therapy gave divergent results between both antigen tests. For the detection of HIV antigen in single serum samples from HIV-infected patients in different stages of HIV infection, a higher number of positive samples was detected with the Abbott HIV-1 antigen monoclonal antibody assay in samples from patients in stages II and III of HIV infection. The Enzymun-Test detected three or more positive samples than did the Abbott assay among the samples of patients with AIDS. The concordance on a sample-to-sample basis between the Boehringer Mannheim and Abbott EIAs was 98.6%. The sensitivity of the Enzymun-Test in comparison to the reference assay was 97.2%; the specificity was 98.8%. Although no close correlation could be found between the amount of viral RNA in serum detected by nucleic acid sequence-based amplification and the concentration of HIV antigen, a high HIV-1 RNA copy number was mostly associated with high levels of HIV antigen. In conclusion, the Enzymun-Test permits accurate HIV antigen detection and offers, in contrast to previous assays, the possibility of completely automated detection.

AIDS Serodiagnosis↗
PubMed1996

Immunological findings in HIV-Leishmania coinfection.

It is supposed that Leishmania infection increases human immunodeficiency virus (HIV) replication in seropositive individuals. Two groups of 9 HIV-infected intravenous drug users each, one group with HIV-Leishmania coinfection (as determined by bone marrow microscopy, culture and an immunofluorescent assay, the other with HIV infection alone, but no evidence of Leishmania coinfection were matched for sex, age, time since first diagnosis of HIV infection, number of AIDS-defining diseases, proportion of patients treated with AZT and months of treatment, CD4/CD8 ratio, beta 2-microglobulin level and HIV p24 antigen positivity rate. IL-4, -6, -10 and -12 and IFN-gamma levels were determined by commercial enzyme immunoassays. The HIV-1 RNA copy number was quantified with the nucleic-acid-sequence-based amplification method (NASBA). The differences between the two groups were highly significant for all markers determined except for IL-12 and IFN-gamma. We found a higher viral load in the patients with HIV-Leishmania coinfection compared to the patients with HIV infection alone (p < 0.009). In 6 HIV-positive individuals without Leishmania coinfection, the HIV-1 RNA copy number was below the detection limit of NASBA (i. e. < 400 copies/100 microliters). Plasma levels of IL-4, -6, and -10 were significantly elevated in the coinfected group (p < 0.0001; p < 0.02, and p < 0.005). The results of our study show that the viral load is increased in patients with HIV-Leishmania coinfection in comparison to the controls. This might be partly due to Th2 immune activation, as demonstrated by higher plasma levels of IL-4, -6 and -10 in HIV-Leishmania-coinfected patients than in HIV-infected individuals.

AIDS-Related Opportunistic Infections↗
PubMed1996

How accurate is serologic testing of plasma pools for hepatitis B virus surface antigen, anti-human immunodeficiency virus 1 and 2, and anti-hepatitis C virus?

OBJECTIVE: The European pharmacopeia prescribes that, during the manufacture of blood derivates, the first homogeneous pool of plasma (for example, after removal of cryoprecipitate) must be tested for hepatitis B virus surface antigen (HBsAg), for hepatitis C virus (HCV) antibodies and for human immunodeficiency virus (HIV) antibodies using test methods of suitable sensitivity and specificity, in order to reduce the residual risk of infection originating from blood products. The present study was performed to verify if commercially available immunoassays, which are licensed for the screening of single serum and plasma samples, are suitable for the determination of HBsAg, anti-HCV, and anti-HIV in plasma pools. DESIGN: Plasma tools originating from different countries were spiked with HBsAg- and anti-HCV-positive standards (National Institut für Biological Standards, Hertfordshire, UK) and anti-HIV-positive serum. For the determination of HBsAg with and without immune complex dissociation (ICD), anti-HCV and anti-HIV antibodies the Abbott (Delkenheim, Germany) IMx system was used. RESULTS: In contrast to the testing for anti-HIV and anti-HCV, the detection of HBsAg (0.125 IU/ml detection limit) was influenced by the presence of anti-HBs in plasma pools. Statistically significant differences could be observed between anti-HBs-positive plasma pools and anti-HBs-negative serum samples spiked with HBsAg. The kinetics of HBsAg-anti-HBs complex formation showed that in a plasma pool with a high anti-HBs (329.4 IU/ml) concentration HBsAg was not detectable after 5 h of incubation. After ICD, HBsAg was still detectable in the pool with high anti-HBs content. Anti-HIV antibodies could be detected up to a dilution of 1/480,000, anti-HCV up to a dilution of 1/80, both in a spiked negative serum. Overall, the divergences between spiked plasma and serum were relatively low for anti-HCV and anti-HIV detection. CONCLUSION: The Abbott IMx assay permits a highly sensitive detection of HBsAg (after ICD or immediately after thawing of anti-HBs-positive plasma pools), anti-HCV, and anti-HIV in plasma pools. However, in case of a contamination with donations originating from individuals with acute HBV, HIV, or HCV infection or with a poor humoral immune response, serologic testing for HBsAg, anti-HIV, and anti-HCV may fail to detect potentially infectious plasma pools.

AIDS Serodiagnosis↗
PubMed1996

Characterization of major allergens of Parietaria officinalis.

The major allergens of Parietaria officinalis were characterized with a panel of nine monoclonal antibodies (mAbs). The binding of mAbs and patients' IgE in Western blots revealed two proteins with similar molecular weights in the range of 8-10 kD. Analysis of the mAb-binding patterns in Western blots of P. officinalis extract under reducing and nonreducing conditions allows the mAbs to be divided into three different groups. mAbs of group I recognize the higher-molecular-weight component (9.4 kD), mAbs of group II recognize the lower component (8.8 kD) and mAbs of group III recognize both proteins. A comparable mAb-binding pattern was observed with Western blots of Parietaria judaica. The mAbs were used for affinity purification of the corresponding proteins from a P. officinalis extract. The purified proteins obtained with mAbs of group I-III inhibit the binding of patients' IgE (serum pool) to a high degree, indicating that they posses the major IgE-reactive epitopes. The affinity-purified proteins were subjected to SDS-PAGE, blotted and immunologically stained by mAb binding. The results confirmed those obtained with the complete extracts. The N-terminal amino acid sequences of the blotted proteins were analyzed. The sequences of all the proteins contained highly conserved regions: GGVV (positions 4-7) and MPPLL (positions 11-15), alternating with highly variable regions (positions 1-3 for group II and 8-10 for group I). A specific group I sequence appears to be at position 1-3 with the amino acids APA and a specific group II sequence appears to be at position 8-10 with the amino acids GAL. It is possible that the two similar proteins are isoforms of Par o 1.

Allergens↗
PubMed1996

Islet cell surface antibodies are more common in patients and relatives in areas and during seasons with high incidence of insulin-dependent diabetes mellitus.

Although existence of islet cell antibodies (ICA) is regarded as secondary to beta cell death, islet cell surface antibodies (ICSA) might play a role in the disease process. We have collected information from nine European clinics to determine whether ICSA are more common in diabetic children or their relatives in geographical areas or time periods of high incidence of insulin-dependent diabetes mellitus (IDDM). In Finland and Sweden ("North group") with a high incidence of IDDM during childhood, 36% of the patients were positive or weakly positive for ICSA at diagnosis compared with 24% in France (p = 0.1), 11% in Berlin-Vienna (p < 0.01), and 14% in Italy (p < 0.01). This difference was seen in all age groups but was most pronounced in the youngest (0-4 y). This geographical difference was also seen among family members of whom 46% were positive or weakly positive in the North group, 25% in France (p < 0.001), 21% in Berlin-Vienna (p < 0.001), and 16% in Italy (p < 0.001). Of several analyzed antibodies (ICA, gastric parietal cell, thyroglobulin, and thyroid microsomal), only ICSA showed simultaneous positivity in all family members (r = 0.32, p < 0.01). ICSA were most common in family members of patients with short (< 8 d) duration of symptoms (p < 0.05) and showed a similar seasonality, both in patients and relatives, as the incidence of IDDM. We conclude that the geographical difference in incidence of childhood IDDM in Europe may be associated to similar geographical differences in occurrence of ICSA both in newly diagnosed diabetic children and in their relatives. Simultaneous existence of ICSA in both patients and family members and a similar seasonality for ICSA and incidence of IDDM suggest that ICSA may reflect an ongoing disease process.

Autoantibodies↗