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Biomedical subjects

H Pfister

Publications and source records attributed to H Pfister.

At least 163 records · Page 9Linked to original sources
PubMed1987

Risk of rehospitalization of psychotic patients. A 6-year follow-up investigation using the survival approach.

Risk of rehospitalization was investigated in 100 former psychiatric inpatients with ICD-9 diagnoses of schizophrenia, schizoaffective and affective psychosis in a 6- to 7-year interval following discharge. Subtype of disorder, aftercare characteristics, previous course of illness and specific sociodemographic factors were hypothesized to predict the probability of readmissions to a hospital. For time-related statistical analyses the survival approach and proportional hazards model were used. The risk of rehospitalization varies considerably between the diagnostic subgroups studied, depending on the length of the observation period chosen. Schizophrenics had the highest risk (after 3 years 66%, 6 years 80%), followed by schizoaffective patients (58 and 65%) and affective psychosis patients (41 and 58%). Aftercare in a short defined period after discharge from the hospital reduced significantly the risk of readmission for patients with an affective psychosis and patients who were married. Former rehospitalization increases the risk of a readmission. Severity of psychopathological features had only minor predictive value.

Affective Disorders, Psychotic↗
PubMed1987

Relationship of papillomaviruses to anogenital cancer.

A variety of HPV types infect the anogenital mucosa, giving rise to lesions that differ in clinical appearance, histology, and their risk of malignant progression. HPV-16 is distinguished by a strong association with high-grade intraepithelial neoplasia and the greatest prevalence in anogenital malignancy. Most cancers appear to have a multifactorial etiology, and HPV infection alone is probably insufficient for malignant transformation. However, the consistent association between HPV infection and anogenital cancers emphasizes that the sexually transmitted papillomaviruses may have a necessary role in carcinogenesis. Hence, there is a prospect that vaccination programs may one day allow public health control of HPV infection, thereby eliminating an important risk factor.

Cocarcinogenesis↗
PubMed1986

Classification of the papillomaviruses--mapping the genome.

Papillomaviruses form one genus of the Papovaviridae family. They share common antigenic determinants and their DNAs cross-hybridize under conditions of low stringency. The classification of papillomaviruses is at present based on the host range and the relatedness of the nucleic acids. Isolates are considered independent types if there is less than 50% cross-hybridization in the liquid phase according to a standard protocol. At least 31 human and six bovine papillomavirus types can be differentiated on this basis. The host range does not reflect the natural relationship between the viruses. Subgenera, which differ in biological properties, can be distinguished in outline. Data on overall sequence homology are insufficient for a meaningful classification because two types of virus may be closely related within one genome region and rather heterogeneous in other areas. Some new isolates appear as intermediates between previously well-separated types and complicate the system. A reasonable classification of such types of papillomavirus should be based on homologies between genes that are relevant for differences in the biology of the viruses. A functional mapping of the rather uniformly organized, colinear genomes of papillomaviruses has been started. Genetic studies with bovine papillomavirus type 1 have assigned functions in replication, transformation, gene expression and capsid synthesis to individual open reading frames.

Amino Acid Sequence↗
PubMed1986

Differential regulation of papilloma virus early gene expression in transformed fibroblasts and carcinoma cell lines.

Treatment of bovine papilloma virus (BPV) 1-transformed mouse fibroblasts with cycloheximide led to a 10-fold increase in the amount of viral transcripts, after as little as 1 h of protein synthesis inhibition. Northern blots revealed no qualitative changes in the RNA pattern. Nuclear run-on experiments showed about a 7-fold increase in specific transcriptional activity after cycloheximide treatment. The half-life of BPV1 mRNA was twice as long as in untreated controls. These results indicate that both RNA synthesis and degradation of viral RNA are controlled by labile proteins. Cycloheximide stimulation turned out to be independent of the BPV1 E2 gene activity which enhances viral transcription. Cycloheximide treatment had no effect on the amount of human papilloma virus (HPV) 18 transcripts in cervical carcinoma derived HeLa and C4-1 cells. Transcription of HPV16 in the cervical carcinoma line SiHa was likewise unaffected. The differential regulation of transcription in transformed fibroblasts and cancer-derived cells, and the significance for malignant conversion are discussed.

Amino Acid Sequence↗
PubMed1986

Papillomavirus DNA in warts of immunosuppressed renal allograft recipients.

Renal allograft recipients were shown to have an increased incidence of warts and skin cancers. We examined 148 patients for evidence of wart virus infections and tested for papillomavirus types, which are known to be associated with human malignancies. Of the 148, 36 (24.3%) patients were afflicted with warts at the end of our study period, in contrast to 5 of 148 (3.3%) before transplantation. DNA from 16 different biopsies was extracted by phenol treatment for further virological studies. DNA of human papillomavirus (HPV) 2 was detected three times, DNA of HPV 4 and 10 twice, and DNA of HPV 3 and 16 once each by blot hybridization. One probe led to strong signals with HPV types previously found only in epidermodysplasia verruciformis patients. A correlation between histology and virus type existed in cases of HPV 2, 3, 4, and 10 infections.

Adolescent↗
PubMed1986

Human papillomavirus 25-related DNA in solitary keratoacanthoma.

Solitary keratoacanthomas of 32 patients were screened for the presence of human papillomavirus (HPV) 25 DNA, which was originally isolated and molecularly cloned from warts of an epidermodysplasia verruciformis (Ev) patient. Biotinylated virus DNA was hybridized in situ to thin sections obtained from paraffin-embedded material. HPV DNA was detected in 12 of 32 tumors under stringent conditions, and in 2 additional tumors under relaxed conditions.

Adult↗
PubMed1986

Activity coefficients of salts in highly concentrated protein solutions. II. Potassium salts in isoionic bovine serum albumin solutions.

Mean activity coefficients of different potassium salts KX (X = F-, Cl-, Br-, I-, NO3-, SCN-) have been measured in concentrated isoionic bovine serum albumin (BSA) solutions, by use of the EMF method with ion-exchange membrane electrodes. These solutions may be regarded as simple model systems for the cytoplasm of living cells as far as the influence of the macromolecular component on the activity coefficients of the salts is concerned. Two series of measurements have been carried out: (a) varying the amount of salt from 0.01 to 0.5 molal and maintaining the BSA concentration constant at 20 wt% and (b) varying the protein concentration up to 25 wt% and keeping the salt concentration constant at 0.1 molal. For all salts studied, the mean activity coefficients in the protein-salt solutions increase as the salt concentration rises, when the protein concentration is maintained constant. In the series of measurements (b) the activity coefficients of all salts change linearly with the protein concentration. Marked qualitative differences, however, were observed depending on the anion species, which could be interpreted in terms of specific ion binding of X- to the protein molecule. By taking into account BSA-bound 'non-solvent' water, the results were analyzed in terms of numbers of anions bound per BSA molecule. Comparison with the results of Scatchard, obtained at low protein concentrations, showed only a very small electrostatic effect of the BSA-(X-)v polyions on the activity coefficient of the salts at higher protein and salt concentrations.

Kinetics↗
PubMed1986

Epidermodysplasia verruciformis-associated human papillomavirus 8: genomic sequence and comparative analysis.

Human papillomavirus (HPV) 8 induces skin tumors which are at high risk for malignant conversion. The nucleotide sequence of HPV8 has been determined and compared to sequences of papillomaviruses with different oncogenic potential. The general organization of the HPV8 genome is similar to that of other types. Highly conserved, genus-specific sequences were found in open reading frames (ORFs) E1, E2, and L1. In ORFs E6, E7, and L2, HPV8 is more distantly related, but it was possible to differentiate subgenera in which HPV8 belonged to the HPV1-cottontail rabbit papillomavirus group. Sequences within ORF E4 and part of ORF L2 are rather type specific. HPV8 stands out by several unique features: the considerably reduced size of the noncoding region (397 base pairs), with a seemingly low potential for forming complex secondary structures; a cluster of putative promoter elements in the 3' half of ORF E1; an RNA polymerase III promoter-like sequence close to the C terminus of ORF E2; and of particular interest, the homology between the putative protein encoded by ORF E4 and the Epstein-Barr virus nuclear antigen 2 protein, which may reflect similar mechanisms in virus-mediated transformation.

Amino Acid Sequence↗
PubMed1985

Human papillomavirus DNA in conjunctival papilloma.

A histologically proven conjunctival papilloma was examined for the presence of papillomavirus DNA by nucleic acid hybridization under relaxed conditions. It harbored papilloma-virus-specific DNA, which showed no detectable relationship with that of known virus types when tested under stringent conditions. This demonstrates that conjunctival papillomas are associated with more than one papillomavirus type. Viral diagnosis may turn out to be of prognostic value.

Adult↗
PubMed1985

Genome organization of herpesvirus aotus type 2.

Herpesvirus aotus type 2, a virus commonly found in owl monkeys without overt disease, has a similar genome structure to the oncogenic herpesviruses of nonhuman primates (herpesvirus saimiri, herpesvirus ateles). Virion DNA of herpesvirus aotus type 2 (M-DNA) has an unique 110-kilobase-pair region of low G + C content (40.2%, L-DNA), inserted between stretches of repetitive H-DNA (68.7% G + C, about 41 kilobase pairs per molecule) that are variable in length. A minority of virions contain defective genomes that consist of repetitive H-DNA only. The H-DNA is composed of various types of repeat units that are related in sequence with each other. The two dominant types of repeats (2.3 and 2.7 kilobase pairs) were cloned and compared by restriction enzyme cleavages and partial nucleotide sequencing. They are homologous in at least 1.3 kilobase pairs. The two forms of repeat units are randomly arranged and oriented in tandem. Reassociation kinetics did not allow detection of sequence homologies between H- and L-DNA of herpesvirus aotus type 2 and the respective sequences of oncogenic primate herpesviruses.

Animals↗
PubMed1984

Chromosomal changes in bovine papillomavirus type 1-induced Syrian hamster tumors.

Bovine papillomavirus type 1 (BPV-1) induced fibrosarcomas in the Syrian hamster were studied cytogenetically by G- and C-banding techniques. All tumor derived cells showed chromosome abnormalities that remained stable during serial tumor transplantations. Cells without chromosome abnormalities found in two cultures were derived from the host animals on account of heterochromatin polymorphisms. In most tumors pseudodiploid cells prevailed, some cells were hypodiploid lacking one or two chromosomes, and one tumor showed two hyperdiploid cell clones with one and three additional chromosomes, respectively. Some of the chromosome abnormalities apparently are nonrandom. Three chromosomes (#1, #4, and #15) were most frequently involved in aberrations.

Animals↗
PubMed1984

Comparative evaluation of different enzyme-linked immunosorbent assay systems for the detection of staphylococcal enterotoxins A, B, C, and D.

We compared four versions of the enzyme-linked immunosorbent assay for their suitability for detecting staphylococcal enterotoxins. The sandwich with labeled antibody proved to be the best. We used it with a sorbent consisting of antibody-coated polystyrene spheres reacted with 20 ml of food extract. The sensitivity of the test was 0.1 ng of enterotoxin per ml, which is far below clinical relevance. The succinimidyl-pyridyl-dithio-propionate enzyme coupling method of Pharmacia was superior to the two-step glutaraldehyde technique. Interfering protein A was eliminated by the simple addition of normal rabbit serum to the extracts. A diagnostic kit is now available.

Enterotoxins↗
PubMed1984

Molecular cloning and characterization of the DNAs of human papillomaviruses 19, 20, and 25 from a patient with epidermodysplasia verruciformis.

Five human papillomavirus (HPV) DNAs from lesions of an epidermodysplasia verruciformis patient were cloned in lambda L 47: DNA of HPV 5, which predominated in the carcinoma; DNA of a variant type of HPV 8, which was not detected in the carcinoma DNA by Southern blot hybridization but only by cloning; and DNAs of three papillomaviruses that were isolated from warts. Southern blot and liquid phase DNA-DNA hybridization under stringent conditions showed that the three viruses from warts were new types, which we named HPVs 19, 20, and 25. These viruses cross-hybridized between 3 and 29% among themselves and with HPVs 5 and 8. After physical mapping with several restriction enzymes, the colinear genomes were aligned with HPV 8 DNA to define early and late regions. HPVs 8, 19, and 25 shared homology in different parts of their genomes.

Carcinoma↗