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Biomedical subjects

M Wolf

Publications and source records attributed to M Wolf.

612 records · Page 34Linked to original sources
PubMedDate not supplied

Rapidly progressive hearing loss as a symptom of polyarteritis nodosa.

The hearing loss that occurs in polyarteritis nodosa is due largely to middle ear effusion but usually appears as a mixed type. Pure perceptive hearing loss is rare; only two cases have been reported previously in which sensorineural hearing loss was the initial sign of the disease. A case of profound, rapidly deteriorating perceptive hearing loss in which the etiology was not clear is described. One year after the onset of hearing loss, other manifestations of polyarteritis nodosa led to the diagnosis.

Aged↗
PubMedDate not supplied

Shortcomings of low-cost imaging systems for viewing computed radiographs.

OBJECTIVE: To assess potential advantages of a new PC-based viewing tool featuring image post-processing for viewing computed radiographs on low-cost hardware (PC) with a common display card and color monitor, and to evaluate the effect of using color versus monochrome monitors. MATERIALS AND METHODS: Computed radiographs of a statistical phantom were viewed on a PC, with and without post-processing (spatial frequency and contrast processing), employing a monochrome or a color monitor. Findings were compared with the viewing on a radiological Workstation and evaluated with ROC analysis. RESULTS: Image post-processing improved the perception of low-contrast details significantly irrespective of the monitor used. No significant difference in perception was observed between monochrome and color monitors. The review at the radiological Workstation was superior to the review done using the PC with image processing. CONCLUSION: Lower quality hardware (graphic card and monitor) used in low cost PCs negatively affects perception of low-contrast details in computed radiographs. In this situation, it is highly recommended to use spatial frequency and contrast processing. No significant quality gain has been observed for the high-end monochrome monitor compared to the color display. However, the color monitor was affected stronger by high ambient illumination.

Humans↗
PubMedDate not supplied

A model for intracellular translocation of protein kinase C involving synergism between Ca2+ and phorbol esters.

The activation of protein kinase C by diacylglycerol and by tumour promoters has implicated this enzyme in transmembrane signalling and in the regulation of the cell cycle. In vitro studies revealed that catalytic activity requires the presence of calcium and phospholipids with a preference for phosphatidylserine. Diacylglycerol and tumour promoters such as phorbol esters bind to the enzyme, leading to its activation while sharply increasing its affinity for Ca2+ and phospholipid. Addition of diacylglycerol analogues or phorbol esters to intact cells results in the phosphorylation of specific polypeptides. Several cellular processes, including hormone and neurotransmitter release and receptor down-regulation, are modulated by the activation of protein kinase C, while phorbol ester-induced stimulation of the enzyme in whole cells has been associated with its translocation from the cytoplasm to the plasma membrane. Moreover, the use of Ca2+ ionophores has revealed an apparent synergism between Ca2+ mobilization and protein kinase C activation. This synergism has recently also been found to apply to receptor down-regulation (ref. 23 and accompanying paper). Here we describe a reconstitution system in which intracellular translocation of protein kinase C and the synergism between Ca2+ and enzyme activators can be studied. The results suggest a rationale for concomitant Ca2+ mobilization and diacylglycerol formation in response to some hormones, neurotransmitters and growth factors.

Calcium↗
PubMedDate not supplied

Role of intracellular calcium mobilization in the regulation of protein kinase C-mediated membrane processes.

Phorbol esters are potent tumour-promoting agents that exert pleiotropic effects on cells. Among these are the control of growth, stimulation of release of stored bioactive constituents and regulation of growth-factor surface receptors. Phorbol esters bind to and activate protein kinase C, leading to the phosphorylation of specific protein substrates presumed to be necessary for eliciting the full response. Strong evidence exists that specific binding of tumour promoter occurs at the membrane level in intact cells, resulting in activation of protein kinase C. Recent evidence concerning the release of bioactive constituents from platelets and neutrophils has linked agonist-induced protein kinase C activation and Ca2+ mobilization in a synergistic mechanism. Here we present a novel model of synergism between Ca2+ and phorbol esters that leads to transferrin receptor phosphorylation and down-regulation in HL-60 human leukaemic cells. Raising intracellular Ca2+, although ineffective by itself, increases the potency and rate of action of phorbol ester for activating protein kinase C and mediating transferrin receptor phosphorylation and down-regulation. We propose a molecular model in which increased intracellular Ca2+ recruits protein kinase C to the plasma membrane, thus "priming' the system for activation by phorbol ester.

Calcimycin↗
PubMedDate not supplied

Detection of HLA antibodies by platelet crossmatching techniques.

Thirty-seven monospecific HLA antibodies directed against all common HLA-A and -B loci and reactive by the microlymphocytotoxicity assay (LCT) were tested against platelets carrying the corresponding antigen by three platelet crossmatch methods, the platelet immunofluorescence test (PIFT), platelet enzyme-linked immunosorbent assay (P-ELISA), and platelet radioimmunoassay (P-RIA). Positive reactions were obtained with the PIFT in 67 percent, the P-ELISA in 41 percent, and the P-RIA in 49 percent of 85 cell-serum pairs. The same cell-serum combinations gave 49 percent positive reactions in the lymphocyte immunofluorescence test. Three multispecific HLA antisera were positive in nine of nine cell-serum combinations by all four methods. Thirteen transfusions were given to eight patients with known HLA antibodies. All donor-recipient pairs were LCT positive, six were PIFT positive, and seven were PIFT negative. Three of seven PIFT-negative and none of six PIFT-positive transfusions were successful. Thus, platelet crossmatching is less sensitive than the LCT for the detection of complement-binding monospecific HLA antibodies. The platelet crossmatch, however, is able to identify some potentially successful HLA-incompatible donors for patients with multispecific HLA antibodies and limited access to HLA-identical donors.

Antibodies↗
PubMedDate not supplied

Enhanced selectivity in the determination of delta9-tetrahydrocannabinol and two major metabolites in serum using ion-trap GC-MS-MS.

Cannabinoids were extracted from serum with C18 SPE cartridges and analyzed as their trimethylsilyl (TMS) derivatives. A benchtop gas chromatography-tandem mass spectrometry (GC-MS-MS) system based on an ion trap with external ionization was used. Quantitation was done in relation to trideuterated internal standards in dual MS-MS mode. Confirmation of the identity for the three compounds of interest, delta9-tetrahydrocannabinol (THC), 11-hydroxy-delta9-tetrahydrocannabinol (11-OH-THC), and 11-nor-9-carboxy-delta9-tetrahydrocannabinol (THCCOOH), was achieved by registering the daughter spectra in full scan mode. It was possible to identify the three compounds at concentrations down to 0.25 microg/L for THC, 0.5 microg/L for 11-OH-THC, and < 2.5 microg/L for THCCOOH by comparison with reference spectra. The limits of quantitation are better than 2 microg/L for THC, 5 microg/L for 11-OH-THC, and 8 microg/L for THCCOOH. The within-run and day-to-day precision for the three analytes were very similar and ranged from 4.2 to 10.4%.

Dronabinol↗
PubMedDate not supplied

Tamoxifen or cyproterone acetate in combination with buserelin are ineffective in patients with pancreatic adenocarcinoma.

Experimental evidence and preliminary clinical data suggest a responsiveness of pancreatic adenocarcinoma to sex hormones and LH-RH agonists. In this study, we investigated the effect of the antiestrogen tamoxifen and the antiandrogen cyproterone acetate in combination with the LH-RH agonist buserelin in 9 patients with unresectable pancreatic adenocarcinoma. In all patients the disease was progressive under this therapeutic regimen. In conclusion, complete androgen blockade and antiestrogens in combination with LH-RH agonist cannot be recommended in patients with widespread pancreatic adenocarcinoma.

Adenocarcinoma↗
PubMedDate not supplied

Retrieval, automaticity, vocabulary elaboration, orthography (RAVE-O): a comprehensive, fluency-based reading intervention program.

The most important implication of the double-deficit hypothesis (Wolf & Bowers, in this issue) concerns a new emphasis on fluency and automaticity in intervention for children with developmental reading disabilities. The RAVE-O (Retrieval, Automaticity, Vocabulary Elaboration, Orthography) program is an experimental, fluency-based approach to reading intervention that is designed to accompany a phonological analysis program. In an effort to address multiple possible sources of dysfluency in readers with disabilities, the program involves comprehensive emphases both on fluency in word attack, word identification, and comprehension and on automaticity in underlying componential processes (e.g., phonological, orthographic, semantic, and lexical retrieval skills). The goals, theoretical principles, and applied activities of the RAVE-O curriculum are described with particular stress on facilitating the development of rapid orthographic pattern recognition and on changing children's attitudes toward language.

Automation↗
PubMedDate not supplied

Naming-speed processes, timing, and reading: a conceptual review.

This article integrates the findings in the special issue with a comprehensive review of the evidence for seven central questions about the role of naming-speed deficits in developmental reading disabilities. Cross-sectional, longitudinal, and cross-linguistic research on naming-speed processes, timing processes, and reading is presented. An evolving model of visual naming illustrates areas of difference and areas of overlap between naming speed and phonology in their underlying requirements. Work in the cognitive neurosciences is used to explore two nonexclusive hypotheses about the putative links between naming speed and reading processes and about the sources of disruption that may cause subtypes of reading disabilities predicted by the double-deficit hypothesis. Finally, the implications of the work in this special issue for diagnosis and intervention are elaborated.

Child↗
PubMedDate not supplied

Coincidental supraorbital neuralgia and sinusitis.

Headache interpreted as treatment failure may be encountered after FESS or pharmacological treatment for chronic sinusitis. This persistent symptom may lead, even in the presence of minimal sinus disease, to frequent office visits, medical treatment, primary surgery, and revision procedures. A prospective study of patients with a documented history and imaging-verified sinus disease with persistent atypical refractory headache were evaluated. Diagnostic measures included injection of local anesthetic and response to carbamazepine. Severe neuralgia of the supraorbital nerve was identified in 11 patients with chronic sinusitis, treated either medically or surgically before inclusion in the study. Eight of the patients underwent surgery for sinus disease, and five of them had revision surgery because of persisting complaints. All patients responded favorably to the local injection, and eight were treated with carbamazepine. In certain cases, headache in sinusitis patients may be caused or aggravated by supraorbital neuralgia. Sinus disease is possibly a causative factor but conceivably plays the role of a "red herring." This readily diagnosed and treated coexistence may be more prevalent than recognized formerly.

Adult↗
PubMedDate not supplied

Distribution and number of Clara cells in the normal and disturbed development of the human fetal lung.

In this study the numerical growth and topological distribution of Clara cells were investigated in normal and hypoplastic lungs of fetuses ranging in age from the 10th to the 24th gestational week. In addition, the lungs of premature infants suffering from hyaline membrane syndrome (HMS) and bronchopulmonary dysplasia (BPD) were used as a model of disturbed lung growth in the early postnatal phase. Clara cells were observed to appear in the airway epithelium of fetuses of the 15th gestational week. After the 15th week of gestation the Clara cell number increased monotonously with increasing gestational age, reaching 5.4% Clara cells in the bronchial epithelium and 11.2% in the bronchiolar epithelium at the 24th gestational week. In the investigated period of gestation the Clara cell number was significantly higher in the bronchiolar epithelium compared to the bronchial epithelium. Hypoplastic lungs showed no difference in number and distribution of Clara cells compared to normal age-matched controls. This finding suggests the growth of Clara cells to be relatively accelerated compared to the decreased maturation of the lung parenchyma. The HMS/BPD cases showed normal Clara cell counts in the bronchial epithelium, whereas in the bronchiolar epithelium this value was decreased. This finding is caused by the extreme turnover of the airway epithelium in HMS/BPD; the local distribution of the epithelial damage is speculated to be caused by the physicochemical properties of inhaled oxygen.

Bronchi↗
PubMedDate not supplied

Ready or not: assessing youths' preparedness for independent living.

This article discusses the utility of the Ansell-Casey Life Skills Assessment (ACLSA) in assessing life skills necessary for living successfully in the community upon emancipation from out-of-home care. ACLSA, completed by youths and their caregivers, identifies skills that have been mastered and those yet to be learned. Assessment information can be used for goal setting, strength identification, and relationship building, as well as to direct program planning and training in self-sufficiency services.

Activities of Daily Living↗
PubMedDate not supplied

Mode of action of methotrexate-albumin in a human T-cell leukemia line and activity against an MTX-resistant clone.

Limitations of low mol. wt anticancer drugs are short tumor exposure times and toxicity to normal tissue. Methotrexate (MTX) covalently linked to human serum albumin (HSA) as a macromolecular carrier caused tumor regressions concomitant with a favorable toxicity profile in a clinical phase I trial (Hartung et aL, Clin. Cancer Res., 1999, 5, 753). We examined the uptake, intracellular degradation, metabolism and thymidylate synthase (TS) inhibition of MTX-HSA in the T-cell leukemia line CCRF-CEM and the MTX transport resistant clone CCRF-CEM/MTX. The number of MTX molecules per albumin molecule was determined by electrospray mass spectrometry. A loading ratio (LR) of approximately 1.4 mol MTX/albumin revealed intact complexes with one and two MTX molecules/albumin. In the complex with an LR of 5.7, albumin with up to 16 MTX molecules was seen. MTX-HSA was taken up by CCRF-CEM cells via endocytosis and cleaved by lysosomal enzymes. Liberated MTX was a poor substrate of folylpolyglutamate synthetase and was exported into the medium. TS was inhibited and cell survival was impaired by MTX-HSA in a time- and concentration-dependent manner. CCRF-CEM/MTX cells exhibited a growth inhibition of 30-40% after MTX-HSA treatment, but no TS inhibition. The alternative uptake route via endocytosis enables MTX-HSA to overcome transport resistance to MTX.

Antimetabolites, Antineoplastic↗
PubMedDate not supplied

Reproductive health in Romania: reversing the Ceausescu legacy.

As a result of the restrictive reproductive health policies enforced under the 25-year Ceausescu dictatorship, Romania ended the 1980s with the highest recorded maternal mortality of any country in Europe--159 deaths per 100,000 live births in 1989. An estimated 87 percent of these maternal deaths were caused by illegal and unsafe abortion. Under the Ceausescu regime, all contraceptive methods were forbidden and induced abortion was available only for women who met extremely narrow criteria. Immediately after the December 1989 revolution that overthrew Ceausescu, the new government removed restrictions on contraceptive use and legalized abortion. This legislative change has had beneficial effects on women's health, seen in the drop in maternal mortality in 1990 to 83 deaths per 100,000 live births--almost half the ratio in 1989. In addition, changes instituted since the revolution have led to the improved availability of reproductive health services and to the creation of new educational and training opportunities related to reproductive health services and to the creation of new educational and training opportunities related to reproductive health. The newly created contraceptive and abortion services have presented health system managers and policymakers with many challenges as they work to expand the availability of high-quality, comprehensive reproductive health care in a setting of economic hardship, political unrest, insufficient infrastructure, and outdated medical knowledge and practice.

Abortion, Legal↗
PubMedDate not supplied

[Accident classification of workers in the construction industry in the 2d half of life].

On the basis of 3,631 accidents from the Surgical Department of the Central Outpatient's Department of construction workers it could be established by means of the industrial-medical diagnostic accident index numbers that an adequate estimation of function, work and capability is also possible in the second half of life. It is in accordance with the biological age characteristics that in the second half of life twice as much moderately severe and severe accidents have been registered as in the first one, and that this also applies to selected injuries such as fractures, contusions and open wounds.

Accidents, Occupational↗
PubMedDate not supplied

[Light- and electron microscopy of human epididymis after estrogen and antiandrogen treatment].

Epididymal tissue from 8 patients treated with estrogen and antiandrogen for a long time was studied by light- and electron microscopy. There are severe regressive-degenerative changes within the epithelium characterized by a decrease or loss of the normal surface differentiation, a decrease of cell organelles and an increase of phagolysosomes. Hyperplasia of the smooth muscle layer occurs in the extra-epithelial part of the ductus epididymidis.

Adult↗