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Biomedical subjects

H Wolff

Publications and source records attributed to H Wolff.

At least 55 records · Page 3Linked to original sources
PubMed1999

The design, construction and calibration of a carefully controlled source for exposure of mammalian cells to extremely low-frequency electromagnetic fields.

Despite some epidemiological evidence for an association between increased risk of cancer and exposure to electromagnetic fields (EMFs), cancer causation by such exposure remains unproven. Furthermore, for reasons such as biological unresponsiveness of the chosen system, poor equipment design and experimental confounders, no reproducible effects on animals or mammalian cells in culture have been demonstrated following exposure to power frequency EMFs at levels normally encountered in residential settings (<10 to 1000 microT). The apparatus described here, designed specifically to perform large, well-controlled cell biology experiments, reduces extraneous variables to the absolute minimum, so that small effects cannot be ascribed to some cause unrelated to the experimental protocol. Our novel apparatus consists of two identical solenoids which, in use, only differ by whether the field-producing current is flowing or not; they do not influence one another in any way. They are supplied with conditioned air from a common tissue culture incubator, are completely screened from environmental a.c. fields with Mumetal shielding and can be operated under normal laboratory conditions. Furthermore, the arrangement is such that the investigator is unaware whether cells have, or have not, been exposed until after the results have been evaluated. We report the design, construction, calibration and potential uses of this source.

Animals↗
PubMed1999

Receptor tyrosine kinase and p16/CDKN2 expression in a case of tripe palms associated with non-small-cell lung cancer.

BACKGROUND: Tripe palms is a descriptive term for a cutaneous paraneoplastic keratoderma. Tripe palms are frequently associated with gastric and pulmonary carcinoma. The pathogenetic mechanism remains unknown. OBJECTIVE: To determine the influence of receptor tyrosine kinases, which are both expressed in pulmonary carcinomas and in human skin, we performed expression studies on epidermal growth factor receptor (EGFR), HER2, HER3 in a skin sample of tripe palms obtained from a patient with non-small-cell lung cancer with lymph node involvement. Two months after diagnosis, the patient had developed palmoplantar 'tripe palms'. Additionally, the expression of SRC, c-myc and p16/ CDKN2 were studied. METHOD: Conventional reverse-transcription polymerase chain reaction was performed on a tissue sample of tripe palms. RESULTS: Weak expression of HER2 and of p16/CDKN2 was found. EGFR, HER3, c-myc and SRC were not expressed. CONCLUSION: Receptor tyrosine kinases of subclass I, the tyrosine kinase SRC and the oncogene c-myc play no major role in the pathogenesis of this case of tripe palms.

Aged↗
PubMed1999

Cloning of cDNA for rat pro alpha1(V) collagen mRNA. Expression patterns of type I, type III and type V collagen genes in experimental granulation tissue.

A cDNA clone for rat pro alpha1(V) collagen mRNA was constructed using PCR amplification, with primers based on human and hamster COL5A1 gene sequences. The clone pRCVA1 is 560 nucleotides long and it encodes for the carboxy propeptide of type V procollagen. Homology shared with type I collagen sequence was 64%, with type II collagen 65% and with type III collagen 61%. To evaluate the spatial and temporal expression of type V collagen mRNA in wound healing model, subcutaneously implanted viscose cellulose sponges in rats were used to induce granulation tissue formation. Analyses on granulation tissue were carried out on days 5, 8, 14, 21, 30, 59 and 84. Specific cDNA probes to pro alpha1(I), pro alpha1(III) and pro alpha1(V) collagen mRNA were used in slot blot, Northern and in situ hybridization. Type I collagen gene expression was upregulated at the initial stage of wound healing, type III collagen gene expression was constant and from the day 14 onwards type I and III collagen gene expressions were at the same level. Type V collagen gene expression was seen at every time point studied but at a considerably lower level than type I and III collagens. In situ hybridization showed that type V collagen was expressed in two different cell types. In conclusion, type V collagen was expressed in the wound healing model from at least day 5 onwards and it was synthesized by fibroblast-like and rounded cells.

Actins↗
PubMed1999

Current management of androgenetic alopecia in men.

Androgenetic alopecia (AGA) is a common dermatological condition affecting both men and women. Until recently there has been little interest in AGA as a clinical condition, largely due to the lack of any genuinely effective treatment for it. A number of "remedies" exist, such as vitamin supplements, which are not generally harmful but which have no proven efficacy in promoting hair growth or preventing further hair loss. Hair systems and surgery provide camouflage for the symptoms but do not effect a cure. By far the most promising approaches to the treatment of AGA are drug therapies, such as minoxidil and finasteride. Finasteride, an inhibitor of the type II 5alpha-reductase that converts testosterone to dihydrotestosterone, has been shown to prevent further hair loss, and promotes new hair growth in the majority of the men taking part in clinical trials. Tailored drug approaches like this offer the greatest hope for the successful future treatment of AGA.

Alopecia↗
PubMed1998

Expression of cyclooxygenase-2 in human lung carcinoma.

Epidemiological studies indicate that the use of aspirin decreases incidence of and mortality from gastrointestinal cancers. A major target of aspirin and other nonsteroid anti-inflammatory drugs is cyclooxygenase (Cox), the rate-limiting enzyme in the conversion of arachidonic acid to prostanoids. Two Cox genes have been cloned (Cox-1 and Cox-2), of which Cox-2 has recently been found to be expressed in several human carcinomas. We have now studied the expression of Cox-2 mRNA and protein in human lung adenocarcinoma, squamous cell carcinoma, and small cell lung cancer. Cox-2 mRNA steady-state levels were high in well-differentiated adenocarcinoma samples, but low in poorly differentiated adenocarcinoma, squamous cell carcinoma, and small cell lung cancer, as detected by Northern blot analysis. Immunohistochemistry showed Cox-2 staining in 19 of 21 adenocarcinomas. However, well-differentiated adenocarcinomas contained more Cox-2 staining than the poorly differentiated ones. Expression of the Cox-2 protein was also seen in all 11 squamous cell carcinomas studied, although the level of staining seemed to be less than that in the adenocarcinomas. Small cell lung cancer specimens (n = 4) stained with a relatively weak intensity. Interestingly, atypical alveolar epithelium, which associates with asbestosis and idiopathic fibrosing alveolitis and is considered to be a precursor lesion for lung cancer, expressed the Cox-2 protein. Our data, thus, suggest that Cox-2 is expressed in human lung carcinomas and in precursor lesions leading to this malignancy.

Adenocarcinoma↗
PubMed1998

Signalling initiated with CD4-TCR or TCR-TCR interactions: comparison of tyrosine phosphorylation patterns and CD45 effects.

Antigen-triggered response in T cells is mediated by the T cell receptor (TCR)/CD3-complex. This signalling, however, is modulated by a number of other surface molecules. Among the most important of these is the CD4/CD8 molecule which associates with the TCR/CD3-complex and binds to the MHC complex. The molecular mechanisms involved in interactions between TCR-TCR and TCR-CD4 are not fully understood. We have earlier described an experimental model that allows us to dissect signals involving CD4-TCR interactions and those involving TCR-TCR interactions using a mouse CD4-CD8- T cell hybridoma cell-line transfected either with the TCR from a mouse T-helper 2 cell-line (D10) alone or with both the TCR and the CD4 molecule. To further characterize these two different modes of signalling in T lymphocytes we have studied the tyrosine phosphorylation patterns resulting from these interactions. In addition, we have studied the modulatory effect of the CD45 molecule on these interactions. In contrast to some earlier reports, we found that both the patterns of induced tyrosine phosphorylation and the effects of CD45 modulation were essentially similar in the CD4-TCR and the TCR-TCR signal transduction cascades. The results are consistent with a purely synergistically amplifying function for CD4 on the TCR-mediated signalling.

Animals↗
PubMed1998

Folliculitis spinulosa decalvans: successful therapy with dapsone.

A 27-year-old male patient presented with scaly erythema and crusts on the scalp. Since birth, he suffered from dry skin and inflammation of the eyelids. Scarring alopecia was noticed in some regions of his scalp. Folliculitis spinulosa decalvans was diagnosed. Therapy with isotretinoin and topical corticosteroids was without effect. In contrast, 100 mg of Dapsone per day led to resolution of the inflammatory signs. This enabled him to cover the disfiguring scarring alopecia with a permanent hairpiece. His condition has been stable after 18 months without the enlargement of the scarred alopecic areas.

Adrenal Cortex Hormones↗
PubMed1998

Methods for the detection of male genital tract inflammation.

Male genital tract inflammation is reflected by increased numbers of white blood cells (WBC) in semen. An ejaculate containing more than 10(6) WBC ml-1 semen is termed leukocytospermic. Among male infertility patients, the frequency of leukocytospermia is between 10% and 20%. By conventional light microscopy or sperm staining techniques, it is not possible to reliably differentiate WBC from immature germ cells in semen. In contrast, the cytochemical peroxidase method reliably identifies granulocytes, the most prevalent WBC type in semen. The method is cheap, fast and easy to perform. The gold standard for the detection of all WBC populations in semen is immunocytology using monoclonal antibodies. However, it is expensive and time-consuming, thus remaining a research tool at present. The measurement of granulocyte elastase in semen provides information on the number of granulocytes and their inflammatory activation. However, commercial granulocyte elastase enzyme immunoassays are expensive and due to logistical reasons often delay the results for more than 1 week. Leukocyte esterase dipstick tests lack both sensitivity and specificity for the detection of inflammatory changes in semen. For clinical purposes, the peroxidase method is ideally suited to detect inflammatory changes in semen.

Chlamydia trachomatis↗
PubMed1998

Identification of a new site for ferrichrome transport by comparison of the FhuA proteins of Escherichia coli, Salmonella paratyphi B, Salmonella typhimurium, and Pantoea agglomerans.

The fhuA genes of Salmonella paratyphi B, Salmonella typhimurium, and Pantoea agglomerans were sequenced and compared with the known fhuA sequence of Escherichia coli. The highly similar FhuA proteins displayed the largest difference in the predicted gating loop, which in E. coli controls the permeability of the FhuA channel and serves as the principal binding site for the phages T1, T5, and phi80. All the FhuA proteins contained the region in the gating loops required in E. coli for ferrichrome and albomycin transport. The three subdomains required for phage binding were contained in the gating loop of S. paratyphi B which is infected by the E. coli phages, whereas two of the subdomains were deleted in S. typhimurium and P. agglomerans which are resistant to the E. coli phages. Small deletions in a surface loop adjacent to the gating loop, residues 236 to 243 and 236 to 248, inactivated E. coli FhuA with regard to transport of ferrichrome and albomycin, but sensitivity to T1 and T5 was fully retained and sensitivity to phi80 and colicin M was reduced 10-fold. Full-size FhuA hybrid proteins of S. paratyphi B and S. typhimurium displayed S. paratyphi B FhuA activity when the hybrids contained two-thirds of either the N- or the C-terminal portions of S. paratyphi B and displayed S. typhimurium FhuA activity to phage ES18 when the hybrid contained two-thirds of the N-terminal region of the S. typhimurium FhuA. The central segment of the S. paratyphi B FhuA flanked on both sides by S. typhimurium FhuA regions conferred full sensitivity only to phage T5. The data support the essential role of the gating loop for the transport of ferrichrome and albomycin, identified an additional loop for ferrichrome and albomycin uptake, and suggest that several segments and their proper conformation, determined by the entire FhuA protein, contribute to the multiple FhuA activities.

Amino Acid Sequence↗
PubMed1998

Type V collagen in experimental granulation tissue.

To evaluate the spatial and temporal expression of type V collagen in a wound healing model, subcutaneously implanted viscose cellulose sponges in rats were used to induce granulation tissue formation. Analyses on granulation tissue were carried out on days 3, 5, 8, 14, 21, 30, 59 and 84. Acid soluble collagens were extracted and the relative amount of type V collagen was quantified by SDS-PAGE. Specific antibodies to type I, III and V collagens were used in immunohistochemistry and specific RNA probes to proalpha1(I), proalpha1(III) and proalpha1(V) collagen in in situ hybridization. Type V collagen content increased relative to type I and III collagens up to day 8 and remained at the same level for up to the three months. Type V collagen was expressed strongly in blood vessel walls as seen in immunohistochemistry. In situ hybridization showed that all of the three types of collagen were expressed mostly in fibroblast-like cells and also in rounded cells, especially type V collagen. In conclusion, type V collagen was seen in the wound healing model in increasing amounts from day 3 onwards, its localization being highly associated with blood vessels in granulation tissue and it was synthesized by fibroblast-like and rounded cells.

Animals↗