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P Hauser

Publications and source records attributed to P Hauser.

At least 73 records · Page 4Linked to original sources
PubMed1992

Properties of a recombinant yeast-derived hepatitis B surface antigen containing S, preS2 and preS1 antigenic domains.

Yeast cells have been engineered to express mixed HBsAg particles containing the S and a modified large (L*) protein. Their construction resulted in reduced protease sensitivity, reduced glycosylation and complete inactivation of the polymerized human albumin binding site. The particles exposed the S, preS1 and preS2 antigenic determinants and induced an immune response against the three domains. Highly purified preparations have been obtained and are presently being tested in human volunteers.

Animals↗
PubMed1992

Role of a pituitary-specific transcription factor (pit-1/GHF-1) or a closely related protein in cAMP regulation of human thyrotropin-beta subunit gene expression.

cAMP regulation of the human thyrotropin-beta (TSH beta) gene cAMP was studied in two heterologous cell lines, a human embryonal kidney cell line (293) and a rat pituitary cell line (GH3). In 293 cells, human TSH beta gene expression was not stimulated by the adenylate cyclase activator forskolin or the cAMP analogue 8-bromo-cAMP (8-Br-cAMP). On the other hand, these agents induced human TSH beta gene expression 4-12-fold in GH3 cells. Deletion analysis demonstrated that the regions from +3 to +8 bp and from -128 to -61 bp were both necessary for cAMP stimulation. The latter region contains three DNA sequences homologous to a pituitary-specific transcription factor, Pit-1/GHF-1, DNA-binding site. Gel-mobility assays demonstrated that a radiolabeled human TSH beta probe (-128 to -61 bp) formed five specific DNA-protein complexes with mouse thyrotropic tumor (MTT) nuclear extract and two specific complexes with in vitro translated Pit-1/GHF-1. Four of the five MTT complexes and both in vitro Pit-1/GHF-1 complexes were reduced or eliminated by excess of an unlabeled Pit-1/GHF-1 DNA-binding site from the rat growth hormone gene, but not a mutated version of the same DNA fragment, suggesting that Pit-1/GHF-1 or a closely related thyrotroph protein binds to these DNA sequences. In 293 cells, co-transfection of an expression vector containing the Pit-1/GHF-1 cDNA restored cAMP-responsiveness to the human TSH beta promoter (5.2- and 6.6-fold maximal stimulation by 8-Br-cAMP and forskolin, respectively) but not the herpes virus thymidine kinase promoter (1.2-fold maximal stimulation by either agent). Thus we conclude that the human TSH beta gene is positively regulated by cAMP in GH3 but not 293 cells. Since the human TSH beta gene contains at least one high-affinity binding site for Pit-1/GHF-1 in a region necessary for cAMP stimulation and cAMP stimulation could be restored to the human TSH beta promoter in a previously nonresponsive cell line by the addition of Pit-1/GHF-1, this suggests that Pit-1/GHF-1, or a closely related protein in the thyrotroph, may be a trans-acting factor for cAMP stimulation of the TSH beta gene.

Animals↗
PubMed1992

Loss of the common "A" determinant of hepatitis B surface antigen by a vaccine-induced escape mutant.

A previous study (Carman, W. F., A. R. Zanetti, P. Karayiannis, J. A. Waters, G. Manzillo, E. Tanzi, A. J. Zuckerman, and H. C. Thomas. 1990. Lancet. 336:325-329) demonstrated a variant hepatitis B surface antigen (HBsAg) in a vaccinated child born to a hepatitis B virus-infected mother. A substitution of arginine for glycine at amino acid 145 in HBsAg was observed. In this study the effect of this substitution on the common "a" determinant of this protein, against which protective immunity is directed, is investigated. Using recombinant HBsAg with and without the amino acid substitution, the binding of monoclonal antibodies that recognize different epitopes of the "a" determinant, was shown to be destroyed by the presence of arginine at amino acid 145. In convalescent and vaccinee sera, antibody binding to HBsAg was not inhibited by the variant HBsAg. Immunization with the variant HBsAg, although eliciting a high titer antibody that recognized the variant, produced a low titer of antibody recognizing the native protein. Studies in mice demonstrate that the immunogenicity of the variant protein is also substantially altered. The data presented here demonstrate that this variant evades the known protective anti-HBs response and lends support to the suggestion that this mutation arose as the result of immune pressure.

Animals↗
PubMed1992

Effects of carbamazepine on pituitary-adrenal function in healthy volunteers.

Carbamazepine (CBZ) is a widely used therapeutic agent in seizure, pain, and mood disorders. Although CBZ has been shown to inhibit hypothalamic CRH secretion in vitro, limited data suggest that systemic CBZ induces pituitary-adrenal activation. Few data are available to reconcile these effects or clarify their mechanism(s), particularly in healthy human subjects. We report here a study of basal ACTH and cortisol secretion and their responses to ovine CRH administration in nine healthy volunteers, studied both during repeated (2-3 weeks) administration of CBZ and while medication free. CBZ significantly increased mean 24-h urinary free cortisol (mean +/- SE, 197 +/- 17 vs. 137 +/- 24 nmol/day; P less than 0.02) and evening basal total plasma cortisol (113 +/- 17 vs. 83 +/- 14 nmol/L; P less than 0.05) as well as cortisol-binding globulin-binding capacity (497 +/- 36 vs. 433 +/- 28 nmol/L; P less than 0.01). Despite the CBZ-induced hypercortisolism, plasma ACTH responses to CRH during CBZ treatment remained robust, rather than being suppressed by basal hypercortisolism. In fact, during CBZ treatment, we noted a positive correlation between the increase in basal plasma cortisol and the increase in the plasma ACTH response to CRH (r = 0.65; P less than 0.05). We also observed a reduction in cortisol-binding globulin-binding capacity after CRH administration (315 +/- 25 vs. 433 +/- 28 nmol/L; P less than 0.001), which was accentuated by CBZ treatment (342 +/- 19 vs. 497 +/- 36 nmol/L; P less than 0.001; magnitude of fall, -155 +/- 22 nmol/L on CBZ vs. -118 +/- 11 nmol/L off CBZ; P less than 0.05). We conclude that CBZ increases plasma cortisol secretion in healthy volunteers independent of its effect on plasma cortisol-binding capacity. This pituitary-adrenal activation seems to reflect a pituitary, rather than a hypothalamic, effect of CBZ. Hence, despite CBZ-induced hypercortisolism, the ACTH response to CRH remained robust in direct proportion to the CBZ-induced rise in basal plasma cortisol. Thus, we propose that the increased cortisol secretion observed during CBZ treatment reflects a relative inefficacy of glucocorticoid negative feedback at the pituitary. This pituitary-driven increase in cortisol secretion combined with the expected reduction in centrally directed CRH secretion could contribute to the anticonvulsant properties of CBZ.

Adrenocorticotropic Hormone↗
PubMed1992

Correlations of language abnormalities with localization of mutations in the beta-thyroid hormone receptor in 13 kindreds with generalized resistance to thyroid hormone: identification of four new mutations.

Generalized resistance to thyroid hormone is an inherited disease characterized by unresponsiveness of pituitary and peripheral tissues to thyroid hormone. Genetic analysis of several kindreds linked this syndrome to the gene for the beta-form of the thyroid hormone receptor, and this led to the subsequent identification of various mutations in the ligand-binding domain of this receptor. In this region we now have found 4 new point mutations with reduced T3-binding affinities from separate kindreds by direct sequencing of polymerase chain reaction products. Similar to previously studied kindreds, the reduction in T3 binding of these four kindreds ranged from 2.5- to 5-fold, indicating that these are not neutral polymorphisms. Furthermore, the pattern of inheritance of these 4 kindreds is familial in 2, sporadic in 1, and unknown in 1. To date, 20 distinct mutations have been identified, of which 18 are clustered in 2 distinct topographical regions: 11 are within the tau i/dimerization subdomains of exon 9, and 7 are within the L2 subdomain of exon 10. The 4 newly identified mutations coupled to the 9 mutations our laboratory has previously identified provide new insights into the clinical aspects of generalized resistance to thyroid hormone. Kindreds with mutations in exon 9 compared with those in exon 10 have significantly more problems in language development, as manifested by articulation problems and/or wide discrepancies in verbal and performance IQs. Interestingly, marked variability in language deficiency as well as other clinical patterns were seen not only between kindreds but also within a kindred. Further identification and clinical correlations of new mutations will continue to enhance our understanding of the structure/function relationships and physiological role of the human thyroid hormone receptor.

Adolescent↗
PubMed1991

Thyrotropin-releasing hormone regulation of human TSHB expression: role of a pituitary-specific transcription factor (Pit-1/GHF-1) and potential interaction with a thyroid hormone-inhibitory element.

Regulation of human thyrotropin beta subunit gene (TSHB) expression by thyrotropin-releasing hormone (TRH) was examined in a clonal rat pituitary-cell line (GH3). Transient expression studies were done with various 5'-flanking DNA sequences of TSHB coupled to reporter gene chloramphenicol acetyltransferase. Deletion analysis defined two discrete regions (-128 to -92 base pairs and -28 to +8 base pairs) that each mediated an approximately 2-fold TRH induction. The upstream site contains a DNA sequence with close homology to the DNA-binding site for a pituitary-specific transcriptional factor Pit-1/GHF-1. DNase I footprinting analysis of mouse thyrotropic tumor extract as well as DNA-transfection studies using an expression vector containing an N-terminal deletion of Pit-1/GHF-1 cDNA suggest that Pit-1/GHF-1 or a closely related protein in the thyrotroph mediates TRH responsiveness of this gene. In addition, the downstream site overlaps with the recently characterized thyroid hormone-inhibitory element of TSHB. In fact, deletion of DNA sequences important in thyroid hormone-receptor binding (c-erbAB/c-ERBA2) from +3 to +8 base pairs, significantly reduced (30%) TRH responsiveness. The location of a TRH-stimulatory element near a thyroid hormone-inhibitory element may allow for fine control of TSHB expression in vivo.

Animals↗
PubMed1991

HepG2 cell binding activities of different hepatitis B virus isolates: inhibitory effect of anti-HBs and anti-preS1(21-47).

The antigenic relationships among different hepatitis B virus (HBV) isolates were investigated by using monoclonal antibodies (MAbs) specific for HBs, preS2 (pHSA binding site), and preS1 (hepatocyte receptor-binding site) epitopes in a double immunoradiometric assay. In order to define possible functional differences resulting from structural and antigenic differences in the HBV env protein, the HBV isolates were compared in an in vitro cell-binding assay based on the attachment of 125I-labeled HBV to human hepatoma HepG2 cells. We provided evidence for a variability of the expression of preS1 and preS2 specificities in the peplomer (glyco)protein of HBV depending on dly subtype of HBsAg, which could affect the viral infectivity. We showed that the integrity of the HBV envelope structure associated with a large expression of preS1(21-47) epitopes is an essential factor for effective binding to HepG2 cells. Interestingly, the HBs-specific MAbs directed to disulfide-bond-dependent epitopes were found to be the best inhibitors of the preS1-HepG2 cell interaction (greater than 50%, at the final concentration of 0.5 micrograms/ml). The MAb F35.25 directed to the preS1(21-47) sequence corresponding to the hepatocyte receptor recognition site was, however, also found to inhibit binding. Thus, our results demonstrate the abilities of both anti-HBs and anti-preS(21-41) to block the attachment of complete HBV particles to HepG2 cells, suggesting that these antibodies should be virus neutralizing and would be expected to confer protection against reinfection.

Antibodies, Monoclonal↗
PubMed1991

Differential presentation of hepatitis B S-preS(2) particles and peptides by macrophages and B-cell like antigen-presenting cells.

Different cell types, including dendritic cells, macrophages and Ia+ B cells, have been described to present soluble antigen (Ag) to T-cell hybridomas. However, it is still not clear whether these different cell types can act as antigen-presenting cells (APC) for complex and insoluble Ag such as viral particles. Using yeast recombinant hepatitis B S-preS(2)-containing particles, T-cell hybridomas were generated and used as a tool to study processing and presentation of antigen. Different types of APC were compared in regard to their capacity to process and present the protein-lipid composed S-preS(2) particles and the thereof derived T-cell epitope containing peptides by different types of APC. While a S-preS(2)-derived T-cell epitope containing peptide, which does not require processing, could be presented both by macrophage and B-cell like APC, the presentation of S-preS(2) particles required the presence of macrophages. The fact that B-cell like APC and macrophages behave differently with regard to the presentation of S-preS(2) particles suggest that the uptake and/or processing of this type of Ag by B-cell like APC and macrophages is different.

Animals↗
PubMed1990

A base mutation of the C-erbA beta thyroid hormone receptor in a kindred with generalized thyroid hormone resistance. Molecular heterogeneity in two other kindreds.

Generalized thyroid hormone resistance (GTHR) is a disorder of thyroid hormone action that we have previously shown to be tightly linked to one of the two thyroid hormone receptor genes, c-erbA beta, in a single kindred, A. We now show that in two other kindreds, B and D, with differing phenotypes, there is also linkage between c-erbA beta and GTHR. The combined maximum logarithm of the odds score for all three kindreds at a recombination fraction of 0 was 5.77. In vivo studies had shown a triiodothyronine (T3)-binding affinity abnormality in nuclear receptors of kindred A, and we therefore investigated the defect in c-erbA beta in this kindred by sequencing a major portion of the T3-binding domain in the 3'-region of fibroblast c-erbA beta cDNA and leukocyte c-erbA beta genomic DNA. A base substitution, cytosine to adenine, was found at cDNA position 1643 which altered the proline codon at position 448 to a histidine. By allelic-specific hybridization, this base substitution was found in only one allele of seven affected members, and not found in 10 unaffected members of kindred A, as expected for a dominant disease. Also, this altered base was not found in kindreds B or D, or in 92 random c-erbA beta alleles. These results and the fact that the mutation is predicted to alter the secondary structure of the crucial T3-binding domain of the c-erbA beta receptor suggest this mutation is an excellent candidate for the genetic cause of GTHR in kindred A. Different mutations in the c-erbA beta gene are likely responsible for the variant phenotypes of thyroid hormone resistance in kindreds B and D.

Alleles↗
PubMed1989

Benzodiazepine withdrawal delirium with catatonic features. Occurrence in patients with partial seizure disorders.

We report the cases of 3 patients with medically intractable seizures in whom withdrawal of treatment with a long-acting benzodiazepine (clorazepate dipotassium, 2 patients; clonazepam, 1 patient) was followed by delirium with catatoniclike features. While an increase in seizure frequency occurred during withdrawal and prior to the onset of behavioral changes, electroencephalograms did not show epileptiform activity during the delirium. We compared these 3 patients with 10 others with intractable seizures in whom antiepileptic therapy was withdrawn without subsequent behavior changes. High-dose benzodiazepine therapy and a history of viral encephalitis may be risk factors for withdrawal delirium.

Adult↗
PubMed1989

Corpus callosum dimensions measured by magnetic resonance imaging in bipolar affective disorder and schizophrenia.

Magnetic resonance imaging (MRI) brain scans were performed on 24 schizophrenic patients, 22 bipolar affective patients, and 25 normal control subjects without medical or psychiatric illness using a Picker Vista 0.5 tesla scanner. Specific callosal regions and the cerebral area on the midsagittal slice were measured utilizing the technique described by Nasrallah et al. (1986). No significant differences were found among diagnostic groups in anterior, mid, or posterior callosal width, callosal area, cerebral area, callosal to cerebral area ratio, or the genu (first quartile) to splenium (fourth quartile) ratio. However, male subjects had a significantly greater callosal and cerebral area than female subjects. Gender differences were shown in the genu to splenium ratio in the control groups, but not the affective or schizophrenic groups. The implications of these gender differences are discussed in relation to other studies.

Adult↗
PubMed1989

Temporal lobe measurement in primary affective disorder by magnetic resonance imaging.

Magnetic resonance imaging brain scans were performed on 17 patients with primary affective disorder and 21 normal subjects. A coronal slice through the temporal lobes at the level of the pons and interpeduncular cistern was selected in each subject, and specific temporal lobe structures and the cerebral area were measured. Ratios between structures of the same hemisphere were calculated. The ratio of the temporal lobe to cerebral area was smaller in patients than controls both on the left (p less than .02) and on the right (p less than .03). The data suggest that patients with primary affective disorder may have a relative decrease in the size of the temporal lobe compared with normal controls.

Adult↗
PubMed1988

Lack of induction of IgE and IgG antibodies to yeast in humans immunized with recombinant hepatitis B vaccines.

Yeast-derived hepatitis B vaccines (partially purified or highly purified) at different dosages and a plasma-derived hepatitis B vaccine (control) were injected into 50 young volunteers 3 times at monthly intervals. Before and 4 weeks after this series of immunizations, blood samples were drawn and tested for presence of IgE and IgG antibodies against yeast antigens. No rise in IgE antibodies against Saccharomyces cerevisiae antigens nor in IgG antibodies against Candida albicans antigens was found. Together with former clinical results this underlines the experience that type I and type III reactions against putative yeast contaminants apparently play no major role after immunization with recombinant hepatitis B vaccines.

Adult↗
PubMed1988

Anomalous motoric lateralization and schizophrenia: clinical implications.

Sixty-five schizophrenic subjects (46 men and 19 women) were tested for motor preference and compared to age and sex-matched controls. There were significantly more nondextrals among the schizophrenic women. Both male and female nondextral schizophrenics were hospitalized more frequently and for longer periods than dextral schizophrenics.

Adolescent↗
PubMed1987

Multicentre dose range study of a yeast-derived hepatitis B vaccine.

Healthy young adult volunteers, 778 in number, without HBV markers were randomly distributed into groups and administered different lots of a yeast-derived hepatitis B vaccine (YDV) at different dose levels or a commercial plasma-derived vaccine (PDV), according to a 0, 1, 2, 12-month vaccination schedule. The YDV proved to be safe and well tolerated, even when partly purified lots were given. Reactions were mild and transient, comparable to those observed after PDV. One month after three YDV doses, 0-7% of subjects overall had failed to seroconvert; all those evaluated one month after the booster dose had seroconverted. No significant difference was found between the two vaccine types as far as seroconversion rates were concerned. Geometric mean anti-HBs levels following three vaccine doses were higher in seroconverters of the PDV groups. However, a booster dose of YDV resulted in high anti-HBs levels in all groups varying from 11,474 to 51,404 IU l-1 (purified YDV lot), 4915 to 18,832 IU l-1 (partly purified YDV lots) and 11,008 to 15,805 IU l-1 (PDV lots). Of seroconverters to the purified lots of YDV 93% attained 1000 IU l-1 after the booster dose, thus ensuring protection for a number of years. Dose-response studies provided a basis for the selection of 20 micrograms of highly purified YDV as the standard dose.

Adult↗
PubMed1987

Immunological properties of recombinant HBsAg produced in yeast.

Although currently available plasma-derived vaccines (PDV) against hepatitis B based on the surface antigen of the virus (HBsAg) are well-tolerated and effective, their supply is limited and time-consuming controls are necessary to assess their safety. It is therefore desirable that an alternative source of HBsAg be found. Recombinant DNA technology has provided the possibility of obtaining HBsAg in large quantities. However, it is important that a recombinant DNA hepatitis B vaccine be not only antigenically similar but also elicits a similar immune response in humans. Using the Ausria kit, the recombinant DNA vaccine of SmithKline Biologicals produced in yeast appears to have a higher antigenic content than a reference plasma-derived HBsAg preparation of similar purity when compared at equivalent protein concentrations. In competition experiments, however, antibodies obtained by immunization with PDV similarly recognized yeast-derived and plasma-derived antigens. Monoclonal antibodies directed to the common a determinant of the whole virus were also used to identify distinct epitopes on the recombinant DNA vaccine. The yeast-derived HBsAg is therefore antigenically similar to plasma-derived HBsAg. The yeast-derived vaccine (YDV) was highly immunogenic in mice, rabbits, goats, monkeys, chimpanzees, and humans. High titres of anti-HBs were reached in humans after three doses administered at 0, 1, and 6 months. The antibodies raised in humans after three doses of YDV were predominantly directed to the common a determinant. Competition studies using monoclonal antibodies raised against the whole virus showed that the antibodies had the same specificity as the antibodies induced by PDV. The affinity for the plasma-derived antigen of antibodies stimulated by YDV and PDV and antibodies present in the sera of convalescent subjects were also similar. Finally, competition experiments showed that the antibodies induced in humans by YDV and antibodies from convalescent subjects were directed to the same binding sites of the plasma-derived antigen. These studies indicate that the yeast-derived vaccine is immunologically similar to the plasma-derived vaccines both in vitro and in vivo and can therefore be expected to have similar protective efficacy.

Animals↗