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Biomedical subjects

H Pfister

Publications and source records attributed to H Pfister.

At least 199 records · Page 11Linked to original sources
PubMed1979

Occupational dose from natural radionuclides in phosphate fertilizers.

In this investigation the occupational exposure of single persons due to the gamma radiation of the natural radionuclides in rock phosphates and phosphate fertilizers and their contribution to the population dose in the FRG has been determined. The exposure rates in the working fields production, transport, loading and storage or rock phosphates and phosphate fertilizers and due to their application in agriculture have been measured by means of scintillation dose rate meters or LiF-thermoluminescence dosemeters or have been estimated from specific activities. Mean additional exposure rates of 2--26 muR/h, with local maximum values up to 190 muR/h, were observed. From these values, together with statistical data for the number of occupied persons and annual working times in the various working fields, the mean and maximum annual dose of individuals and the contribution to the mean population dose have been estimated. The results show that a maximum annual dose to individuals from 0.4 mrem/y (agriculture) up to 45 mrem/y (production plants or storehouses) can occur. The corresponding mean annual doses are 0.05--20 mrem/y. The contribution of the occupational radiation exposure due to rock phosphates and phosphate fertilizers to the mean population dose is 174 man . rem/y related to whole body. To this, fertilizer production contributes 40 man . rem/y, transport and loading 45 man . rem/y, agricultural storehouses 31 man . rem/y, and agriculture 58 man . rem/y. Altogether, this investigation shows that an occupational radiation exposure of individuals may occur which corresponds to the mean terrestrial radiation exposure in the FRG. The contribution of the occupational collective doses due to phosphates to the population dose, however, is negligibly small.

Agricultural Workers' Diseases↗
PubMed1979

Characterization of human papillomavirus 3 in warts of a renal allograft patient.

Multiple flat wart-like lesions of a renal allograft recipient were shown to contain HPV 3 or a serologically crossreacting virus by indirect immunofluorescence with monospecific animal antisera against HPV [1--5]. The patient's serum revealed virus specific antibodies (immunofluorescence titer 1/80). Papillomaviruses were isolated and after in vitro iodination 3 major proteins (MW 70.000, 56.000 and 43.000) were detected by SDS polyacryalmide gel electrophoresis. DNA was extracted from the warts and cleaved with the restriction endonuclease Hae III. Distinct bands were discernible within the background of cellular DNA and these fragments were identified as papillomavirus DNA by blot hypbridization with 32P-labeled viral DNA.

Adult↗
PubMed1979

Seroepidemiologic studies of bovine papillomavirus infections.

Bovine and human sera were analyzed for the presence of antibodies against bovine papillomavirus types 1 and 2 (BPV 1 and 2) and human papillomavirus type 1 (HPV 1) in a solid-phase radioimmunoassay. Human sera did not react with BPV antigens, and bovine sera showed no evidence of antibodies against HPV 1. In contrast, 19% of all bovine sera tested reacted with BPV 1 and 2 antigens, and 35% of human sera revealed antibodies against HPV 1. No serologic evidence was obtained for heterologous infections of persons exposed preferentially to cattle (farmers, butchers, and patients with Q-fever).

Animals↗
PubMed1978

Characterization of proteins of human papilloma viruses (HPV) and antibody response to HPV 1.

The serological characterization of virus isolates from verrucae vulgares and plantar warts revealed that HPV 1 and HPV 4 are present in about 50% of these warts with HPV 1 being more prevalent, especially in plantar warts. Parallel to the high incidence of HPV 1 infections, about 50% of non-selected young adults contained antibodies against HPV 1. Only HPV 4 particles, however, reacted with serum from a patient with epidermodysplasia verruciformis when tested by immuno-electron microscopy. An examination of HPV 1 proteins indicated that the major structural proteins VP2 and VP3 are trypsin sensitive. Tryptic degradation leads to distinct polypeptides with molecular weights between 37,000 and 23,000 which may be correlated to minor protein components of HPV 1 preparations. HPV 1 histone-like proteins, which co-migrate with purified cellular histones in SDS gel electrophoresis were analyzed in an acetic acid urea system. It was shown that H3- and H4-like proteins differ from cellular histones. The reason for this difference and its meaning are discussed.

Adolescent↗
PubMed1978

Seroepidemiological studies of human papilloma virus (HPV-1) infections.

At least two groups of human papilloma viruses can be distinguished serologically: on the one hand HPV 1-3, which are closely related but differ in the restriction enzyme pattern of their DNA, and on the other hand HPV-4. The age distributions of patients with warts induced by HPV 1-3 or by HPV-4, respectively, differ markedly. HPV 1-3 predominates between 5 and 15 years of age, whereas HPV-4 could be isolated more often between the ages of 20-25 years. The large number of HPV-1-3-induced warts in children is paralleled by a high percentage of HPV-1 antibody-positive sera in the same age group (about 50%). With increasing age the percentage of HPV-1 antibody-positive sera decline gradually. This pattern of seroreactivity was compared to that of patients with various papillomas and with several malignant tumors. There is no evidence to suggest a link between HPV 1-3 and condylomata acuminata, laryngeal papillomas or any of the malignant tumors tested.

Adolescent↗
PubMed1978

Activity coefficients of salts in highly concentrated protein solutions. I. Alkali chlorides in isoionic bovine serum albumin solutions.

In order to understand the thermodynamic state of simple salts in living cells, the mean activity coefficients of LiCl, NaCl, KCl, RbCl, CsCl were determined in concentrated isoionic bovine serum albumin (BSA) solutions by use of the EMF method with ion exchange membrane electrodes. The protein concentration range extended up to 22 wt%, whereas the salt concentration was kept constant at 0.1 mole per kilogram water. These solutions may be regarded as crude but appropriate model systems for the cytoplasm of cells as far as type and magnitude of the macromolecular component influence on the chemical potential of the salts is concerned. The mean stoichiometric activity coefficients of the alkali chlorides in the isoionic BSA solutions decreased linearly with the protein molality; this decrease, however, did not exceed ca. 10% compared with the pure 0.1 molal salt solutions. Only very small differences in the behavior of the different alkali chlorides were observed. The results may be interpreted by the superposition of the effects of specific Cl- ion binding to BSA and BSA bound "non-solvent" water with probably electrostatic long range interactions of the BSA(Cl-)nu polyions with the salt ions in solution. The resulting mean activity coefficients, corrected for ion binding and non-solvent water, showed a very slight linear dependence on the protein concentration. The departure from the value in the pure 0.1 molal salt solutions did not exceed +/- 2%.

Biological Transport↗
PubMed1978

Heterogeneity of human papilloma viruses.

Two types of human papilloma viruses (HPV-1 and HPV-4) were characterized, which show no relationship as far as the following criteria are concerned: the pattern of restriction enzyme fragments of their DNA, DNA-cRNA hybridization, and complement fixation with specific rabbit antisera. Furthermore, the molecular weights of the major proteins differed significantly. Both types of viruses could be isolated from plantar warts and from verrucae vulgares. This paper gives the molecular weights of the major proteins of a third type of HPV from skin warts, which reacts neither with HPV-1 nor with HPV-4 rabbit antiserum.

Complement Fixation Tests↗
PubMed1977

Adsorption of a phage tail-like bacteriocin to isolated lipopolysaccharide of Rhizobium.

Purified lipopolysaccharide (LPS) from the bacteriocin sensitive strain Rhizobium lupini i6-2 was shown to neutralize the killing activity of the bacteriocin. In the electron microscopical preparation the phage tail-like bacteriocin appears to be adsorbed to the LPS; the tail sheath is contracted and the fibres are oriented towards the LPS ribbon. In contrast, no interaction was observed between the bacteriocin and the LPS of two resistant strains of Rhizobium (16-2/Ii and 16-3). The inactivation of the bacteriocin by LPS depends on salt concentration, pH, and temperature. The receptor activity of LPS was destroyed by mild acid hydrolysis and by treatment with deoxycholate, which indicates that the micellar structure of the LPS is necessary for bacteriocin adsorption. The chemical composition of the 16-2 LPS was compared to that of the LPS of two resistant strains. In the case of 16-2/ii LPS minor modifications suffice to confer resistance against the bacteriocin.

Acetates↗
PubMed1976

Population dose from natural radionuclides in phosphate fertilizers.

The natural radionuclide content of mineral phosphate fertilizers has been determined gammaspectrometrically. The investigations comprised ca. 70% of the mineral phosphate fertilizers authorized and used in the Federal Republic of Germany (FRG). At maximum, we found specific activities of 62 nCi Unat/kg, 23 nCi 226Ra/kg, 1.6 nCi Thnat/kg and 262 nCi 40K/kg. The mean values, weighted by the percentual agricultural consumption of the main phosphate fertilizer groups in 1973/74 and related to the phosphate content, amounted to 58, 40, 2, and 584 nCi/kg P2O5 for Unat, 226Ra, Thnat, and 40K respectively. This resulted in an annual distribution due to phosphate fertilizing of about 3.9 muCi Unat, 2.7 muCi 226Ra, 0.1 muCi Thnat, and 39.9 muCi 40K per ha of arable or pasture land in 1973/74 on the average. From these values the air dose rates over agricultural areas have been estimated under extreme conservative assumptions resulting in an additional external exposure of members of the population of 0.02 mrd/a on the average and 0.4 mrd/a in the region of highest phosphate fertilizing intensity. If it is assumed that radium contained in phosphate fertilizers were completely accumulated in the soils during the last 80 years, this value would be raised to 0.3 mrd/a on the average. The occupational external radiation exposure due to natural radionuclides contained in phosphate fertilizers was estimated to be 0.1 mrd/a on the average and 2.3 mrd/a at maximum for persons working in agriculture. These estimates show that natural radionuclides in phosphate fertilizers contribute but very little to the mean terrestrial radiation exposure of the population which is 50 to 55 mrd/a in Germany. Only for the small group of persons working in fertilizer production plants or storehouses a significant increase of the external radiation exposure has to be expected which could reach a doubling of the mean natural exposure value.

Agriculture↗
PubMed1975

Attachment of a long-tailed Rhizobium bacteriophage to the pili of its host.

Bacterial strain 16-12 was isolated from the root nodules of lupines and was found to be mitomycin C-inducible for the production of a bacteriophage ("16-12-1") with a long noncontractile tail. The phage was found to attach with a fork-like terminal tail structure to the pili of strain 16-12. In addition, it was also found adsorbed to the bacterial cell poles. It is suggested that phage 16-12-1 may be pilus dependent.

Journal Article↗