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S Kraus

Publications and source records attributed to S Kraus.

At least 19 recordsLinked to original sources
PubMed2002

From quantum Hall ferromagnetism to huge longitudinal resistance at the 2/3 fractional quantum Hall state.

We observe the transition from a spin-unpolarized to a polarized nu=2/3 fractional quantum Hall state at low currents (<5 nA), recently described in terms of quantum Hall ferromagnetism, versus density and parallel magnetic field. At larger currents the time and current dependent huge longitudinal resistance (HLR) is always initiated at the transition. Transport in the HLR regime is linear and the amount of current-induced nuclear polarization in the HLR is comparable to the thermal nuclear polarization at approximately 20 mK and 10 T. A current-induced disorder in the nuclear polarization is speculated to cause the enhanced resistance in the HLR regime.

Journal Article↗
PubMed2002

Evaluating the effects of historic bottleneck events: an assessment of microsatellite variability in the endangered, North Atlantic right whale.

Commercial exploitation reduced the North Atlantic right whale (Eubalaena glacialis) population from c. 12,000 in the 11th century to around 300 by the 21st century. We examine the effect of this population decline on levels of genetic variation at 16 microsatellite loci and contrast levels of variability to that in a closely related species (E. australis). Of the 13 loci developed from the E. glacialis genome, 100% were polymorphic in E. australis. In contrast, nine loci were polymorphic in E. glacialis and four were fixed. Both allelic diversity (A) and heterozygosity (H) were significantly lower in E. glacialis than E. australis (A = 3.2 +/- 2.6 vs. A= 6.9 +/- 3.3, P < 0.001; H= 0.31 +/- 0.25 vs. H= 0.72 +/- 0.23, P < 0.001, respectively). Bottleneck anlayses indicate that the population is in mutation-drift equilibrium and that a genetic bottleneck did not occur during the most recent decline (18th-20th centuries). Nevertheless, low frequency alleles are relatively uncommon in E. glacialis, suggesting that genetic variability has been reduced in this population. Possible origins of low genetic variability are discussed, including the slow but continual erosion of alleles during the 800-year period of decline.

Alleles↗
PubMed2001

Involvement of the ERK mitogen-activated protein kinase in cell resistance to complement-mediated lysis.

Sublytic doses of complement desensitize cells and make them resistant to lytic complement doses. This process, named complement-induced protection, requires calcium ion influx, protein kinase C activation and protein synthesis. The involvement of the extracellular signal-regulated kinase, ERK, in cell desensitization by sublytic complement was examined in erythroleukaemia K562 cells and in COS-7 cells. As shown here, ERK is activated in K562 and COS-7 cells within 10 min of sublytic immune attack and then shows a decline and a second peak of activation at 20 min. C7- and C8-deficient human sera have a small effect on ERK activity. However, a significant increase in ERK activation is observed when C7 or C8, respectively, is added back to these sera. Complement-induced ERK activation was blocked in cells treated with GF109203X or Go6976, two selective PKC inhibitors, as well as by treatment with PD098059, an inhibitor of MEK1, the ERK kinase. PD098059 treatment also sensitized K562 cells to complement-mediated lysis and prevented complement-induced protection. COS-7 cells transfected with a dominant-negative MEK plasmid were incapable of undergoing the process of complement-induced protection. In conclusion, cell desensitization by sublytic doses of the complement membrane attack complex involves a signalling cascade that includes PKC-mediated ERK activation.

Animals↗
PubMed2001

MUC1 in normal and impaired spermatogenesis.

The MUC1 mucin [also known as episialin, epithelial membrane antigen (EMA) or polymorphic epithelial mucin (PEM)] is a component of the mucosal glycocalyx, contributing to anti-adhesive and protective cell functions. MUC1 has been shown in a variety of epithelial cell types in the reproductive tracts of males and females, but this is the first report of its expression in human testis and non-epithelial cells of the germ cell lineage. Analysing 65 testes with normal or impaired spermatogenesis, we identified MUC1 protein in maturing germ cells by immunohistochemistry using the monoclonal antibodies HMFG1, HMFG2 and SM3 binding to different glycosylation variants. MUC1 expression was confirmed by reverse transcription-polymerase chain reaction (RT-PCR) and Western blot analysis on tissue extracts of human testis, and RT-PCR of selected germ cells after UV laser-assisted cell picking. MUC1 glycosylation variants were selectively distributed during normal spermatogenesis. Whereas HMFG1 labelled certain groups of pachytene spermatocytes, HMFG2 labelled only spermatids. Low glycosylated forms of MUC1 mucin, recognized by SM3, were not found. In contrast to its weak expression during normal spermatogenesis, the HMFG1 glycosylation variant accumulated markedly in all spermatocytes showing abnormal or arrested maturation. These results suggest a variable glycosylation of MUC1 mucin in differentiating germ cells, which is aberrant in pathological conditions.

Adult↗
PubMed2000

Cell desensitization by sublytic C5b-9 complexes and calcium ionophores depends on activation of protein kinase C.

Basal cell resistance to lysis by complement C5b-9 complexes depends on extracellular and intracellular protection. Cell membrane regulatory proteins and enzymes interfere with complement activation and intracellular processes of protein phosphorylation and synthesis support cell resistance and damage repair. K562 human erythroleukemic cells treated with sublytic complement doses become protected from lytic doses of complement within 50 min. The early signaling processes leading to cell desensitization to complement-mediated lysis were studied. Treatment with calcium ionophores or phorbol 12-myristate 13-acetate rapidly induced in K562 cells protection from complement as well as synthesis of a large protein complex similar to the large complement-induced protein complex L-CIP induced by sublytic complement. Both ionophore- and complement-induced protection were blocked by treatment with protein kinase C (PKC) inhibitors. Calphostin C, sphingosine and GF109203X abrogated complement-induced protection almost completely, whereas Go6976 inhibited it only partially. Since Go6976 is a selective inhibitor of the conventional PKC type, it is proposed that sublytic complement doses activate both conventional and non-conventional PKC types. Immunofluorescence analysis of K562 cells demonstrated sublytic complement-induced translocation of the conventional PKCalpha and PKCbetaII from the cytoplasm to the plasma membrane. These results indicate that PKC activation is an early obligatory signal in cell desensitization by sublytic C5b-9 or calcium ionophore.

Calcimycin↗
PubMed2000

Mondor's disease of the penis.

Mondor's disease of the penis has been reported after genital trauma such as stretching and torsion of the veins and can cause endothelial necrosis and thrombosis. We report a 35-year-old male with thrombosis of the penile superficial dorsal vein who did not respond to topical drug therapy. Surgical management, e.g. superficial vein resection, is the most effective therapy in refractory cases for relieving pain, diminishing skin induration and producing esthetically pleasing results.

Adult↗
PubMed2000

Planning for an annual episodic mass gathering: emergency department and clinic utilization in Yellowstone.

OBJECTIVE: Planning and providing emergency and primary care for a large transient population of visitors and employees in a national park can be problematic. Furthermore, planning for emergency and primary health care needs of visitors and itinerant workers in a wilderness area national park has not been well documented. A study was performed to analyze emergency and primary health care utilization in a national park. METHODS: Data was gathered from all patients presenting to Lake Hospital Emergency Department in Yellowstone in 1995, and a retrospective chart review was performed. RESULTS: Two distinct populations with different health care needs were identified. CONCLUSION: Utilization analysis revealed differences between conventional mass gatherings and the mass gatherings in Yellowstone. Because of the unique conditions and populations found in a wilderness area, conventional mass gathering emergency medical service models may not be an appropriate model for planning health care in a national park. Analysis of utilization data can help plan resources for emergency and primary health care for a park population.

Adolescent↗
PubMed2000

Sonography for selecting candidates for laparoscopic cholecystectomy: a prospective study.

OBJECTIVE: We assessed the value of sonography in predicting intraoperative difficulties for patients undergoing laparoscopic cholecystectomy and in identifying indicators for conversion to conventional cholecystectomy. SUBJECTS AND METHODS: Upper abdominal sonography was performed (according to a checklist) in 75 consecutive patients before laparoscopic cholecystectomy. Sonographic findings were verified by the surgeon in the operating room. RESULTS: Conversion from laparoscopic surgery to laparotomy was performed in five patients (6.7%). Of 75 patients, 19 had sonograms revealing gallbladder wall thickening (>4 mm); surgical preparation difficulties in 16 of these patients led to laparotomy in four patients. Sensitivity, specificity, positive predictive value, and accuracy of wall thickening as an indicator of technical difficulties were 66.7%, 94.1%, 84.2%, and 85.3%, respectively. Sensitivity, specificity, positive predictive value, and accuracy of wall thickening as an indicator of surgical conversion were 80.0%, 78.6%, 21.1%, and 78.7%, respectively. Technical difficulties at laparoscopy occurred in all five patients with pericholecystic fluid on sonography (sensitivity, 20.8%; specificity, 100%; positive predictive value, 100%; accuracy, 74.7%) and led to laparotomy in three patients (sensitivity 60.0%, specificity 97.1%, positive predictive value 60%, accuracy 94.7%). The accuracy of sonography for cholecystolithiasis was 100%. CONCLUSION: On sonography, gallbladder wall thickening is the most sensitive indicator and pericholecystic fluid is the most specific indicator of technical difficulties during laparoscopic cholecystectomy. Such difficulties may require conversion to laparotomy.

Abdomen↗
PubMed1999

Finasteride in the treatment of men with frontal male pattern hair loss.

BACKGROUND: Finasteride, a specific inhibitor of type II 5alpha-reductase, decreases serum and scalp dihydrotestosterone and has been shown to be effective in men with vertex male pattern hair loss. OBJECTIVE: This study evaluated the efficacy of finasteride 1 mg/day in men with frontal (anterior/mid) scalp hair thinning. METHODS: This was a 1-year, double-blind, placebo-controlled study followed by a 1-year open extension. Efficacy was assessed by hair counts (1 cm2 circular area), patient and investigator assessments, and global photographic review. RESULTS: There was a significant increase in hair count in the frontal scalp of finasteride-treated patients (P < .001), as well as significant improvements in patient, investigator, and global photographic assessments. Efficacy was maintained or improved throughout the second year of the study. Finasteride was generally well tolerated. CONCLUSION: In men with hair loss in the anterior/mid area of the scalp, finasteride 1 mg/day slowed hair loss and increased hair growth.

5-alpha Reductase Inhibitors↗
PubMed1998

Urologic tumors in the Federal Republic of Germany: data on 56,013 cases from hospital cancer registries.

BACKGROUND: Since 1985, a special work group involved in the coordination of hospital cancer registries in Germany (the Arbeitsgruppe zur Koordination Klinischer Krebsregister) has been collecting, storing, and analyzing data on tumor patients received from cancer centers, oncologic departments, and specialized practices. METHODS: The documentation of tumor patients is based on information concerning localization, histologic findings, and tumor spread, among other things. The data are stored in a central data base administered by the work group. It currently contains data on approximately 500,000 oncologic patients. RESULTS: During the period 1987-1992, 56,013 initial entries were made concerning patients with urologic tumors. Of these cases, tumors of the kidney (n = 11,424) constituted 20.4%. In 94.6% of the cases, histologic investigation revealed a renal cell carcinoma, classified as follows: pT1, 5.8%; pT2, 53.6%; pT3, 37.2%; and pT4, 3.4%. Tumors of the urinary bladder (n = 16,246) constituted 29.0% of all urologic tumors. In 93.8% of cases, a transitional cell carcinoma was detected, classified as follows: pTis, 1.0%; pTa, 36.9%; pT1, 29.6%; pT2, 16.9%; pT3, 11.4%; and pT4, 4.4%. Transitional cell carcinomas of the ureter or of the collecting system (n = 1846) constituted 3.3% of the cases. The proportion of testicular tumors (n 6594) amounted to 11.8%; 53.6% of the germ cell tumors (n = 6281) were seminomas and 46.6% were nonseminomas; 66.3% of the cases were lymph node negative. Tumors of the prostate (n = 19,903) constituted 35.5% of the cases. During the period 1987-1992, the proportion of lymph node positive prostate carcinomas decreased, from 39.8% to 16.2%. CONCLUSIONS: A detailed analysis of these data shows how hospital cancer registries can contribute to the discussion of issues regarding diagnosis and therapy of urologic tumors.

Aged↗
PubMed1998

Intratumoral chemotherapy with fluorouracil/epinephrine injectable gel: a nonsurgical treatment of cutaneous squamous cell carcinoma.

BACKGROUND: We attempted to originate a nonsurgical treatment alternative for cutaneous squamous cell carcinoma (SCC), and we evaluated intratumoral modified-release chemotherapy with fluorouracil/epinephrine injectable gel (5-FU/epi gel). OBJECTIVE: To assess the safety and efficacy, we conducted an open-label pilot study of 5-FU/epi gel in 25 patients with biopsy-proven SCC lesions on the face, head, neck, trunk, arms, and hands. METHODS: Each tumor site was injected intradermally with up to 1.0 ml of 5-FU/epi gel. One SCC per patient was treated weekly for up to 6 weeks, then observed for 4 months at which time the tumor site and margins were excised for histologic examination. RESULTS: Overall, 96% (22 of 23) of evaluable treated tumors had histologically confirmed complete tumor clearing. No clinically significant systemic reactions or unexplained treatment-related adverse medical events occurred. The evaluations of the cosmetic appearance of the treated sites, judged subjectively by clinicians and patients, were mostly good to excellent and generally in close agreement. CONCLUSION: Treatment of superficial SCC with 5-FU/epi injectable gel results in a high rate of histologically confirmed complete tumor responses and may provide a nonsurgical treatment alternative in selected patients.

Adult↗
PubMed1997

Longitudinal changes in consensus as a function of acquaintance and agreement in liking.

By using a round-robin design, groups of freshmen reported their impressions of dormmates at 4 different times during the year. Consensus on W. T. Norman's Big Five (1963) did not increase over the year, even though reported acquaintance did increase. Agreement in liking predicted agreement in the trait ratings, such that groups that agreed in their evaluations of one another were more likely to agree in their trait impressions of one another, and vice versa. These patterns, obtained by using trait ratings, were replicated with open-ended descriptions of the targets. Correlations with self-judgments did not increase with acquaintance. The data suggest that increased acquaintance does not produce increased consensus. Instead, the role of agreement in evaluations is explored as a determining factor in the level of obtained consensus.

Cross-Sectional Studies↗
PubMed1997

Intralesional fluorouracil/epinephrine injectable gel for treatment of condylomata acuminata. A phase 3 clinical study.

BACKGROUND AND DESIGN: A new intralesional sustained-release chemotherapy is under development as a treatment for condylomata acuminata; it is administered as an injectable gel that consists of fluorouracil and epinephrine with a purified bovine collagen as the gellant (fluorouracil/epinephrine gel). In this randomized, double-blind study, we evaluated the safety and efficacy of this intralesional treatment in 401 patients, using 2 active drug formulations (fluorouracil/epinephrine gel and fluorouracil gel alone) and a placebo. Each lesion was injected once a week for up to 6 weeks, and patients were followed up for 3 months. RESULTS: A total of 359 patients with 1926 condylomata underwent evaluation. For all lesions treated with fluorouracil/epinephrine gel, the complete response (CR) rate was 77%. For all patients treated with fluorouracil/epinephrine gel, the CR rate was 61%. The fluorouracil/epinephrine gel was significantly more effective (P < .002) in treating condylomata than the fluorouracil gel without epinephrine (CR rate, 43%); both were superior to placebo (CR rate, 5%). At 3 months after completion of treatment, recurrence rates in patients with CRs were as follows: fluorouracil/epinephrine gel group, 50%; fluorouracil gel group, 58%. No clinically significant drug-related systemic reactions occurred. Finally, the type and severity of local tissue reactions of patients with a positive pretreatment collagen skin test result (6/401 [1.5%]) were similar to those of patients with a negative collagen skin test result. CONCLUSION: The fluorouracil/epinephrine injectable gel is a safe and effective treatment for condylomata acuminata.

Adolescent↗
PubMed1996

Trypanosoma cruzi is a potent inducer of interleukin-12 production in macrophages.

Cytokines produced after infection with Trypanosoma cruzi have been shown to be crucial in the determination of resistance or susceptibility. Interferon-gamma (IFN-gamma) is the predominant cytokine produced after infection and has been shown to protect susceptible mice from infection. IFN-gamma production by natural killer cells and T cells is induced by interleukin-12 (IL-12). Therefore, the aim of our study was to analyze the ability of T. cruzi to induce IL-12 production. Spleen cells and bone marrow-derived macrophages incubated with T. cruzi trypomastigotes induced high amounts of IL-12p40 mRNA as shown by reverse transcriptase-polymerase chain reaction. Lipopolysaccharide (LPS) was less efficient in inducing IL-12p40-specific mRNA. Furthermore, biologically active IL-12, detected by the capacity of the supernatant of infected macrophages to induce IFN-gamma production in spleen cells, was produced at very high levels. In comparison, macrophages stimulated with LPS secreted drastically less IL-12. Interestingly, only live, UV- or gamma-irradiated trypanosomes, but not heat-killed parasites or lysates, were functional in this respect. In a kinetic study, in the supernatant obtained from cultures of infected macrophages, IL-12 was already detectable at 2 h after infection, peaked at 32 h and declined after 45 h.

Animals↗
PubMed1995

Stereotypes and ethnocentrism: diverging interethnic perceptions of African American and white American youth.

Much recent work on stereotyping has dealt with groups that are either artificially created or that do not have an extensive history of conflict. The authors attempted to overcome this limitation by examining issues of perceived variability and ethnocentrism among samples of White American and African American youth. The goals were both to examine theoretical issues in stereotyping and to describe the current state of ethnic interrelations among young people. Four studies are reported. Throughout, the samples of African Americans demonstrate interethnic judgments that are consistent with existing work on stereotyping and ethnocentrism. White American students, however, reported judgements that replicate neither the out-group homogeneity effect nor ethnocentrism. Alternative explanations for this difference are considered, and the discussion focuses on differing views concerning the role of ethnic identity and diversity in our society.

Adolescent↗
PubMed1995

[Photo- and videographic determination of the dilatation deficit in differential diagnosis of Horner syndrome].

Physiological anisocoria, a very frequent condition among normal subjects, must be differentiated from Horner's syndrome. Aside from a history including evaluation of older photographs, pharmacological pupil testing with cocaine eye drops has been the "gold standard". Measurement of dilation lag, occurring in Horner's syndrome, is much less common and normal values are missing. Therefore, we evaluated various photographic parameters for testing for the best parameter to discriminate Horner's syndrome (22 patients) from physiological anisocoria (16 patients). Additionally, we tested whether a commercially available camcorder is sufficient to record pupillary dilatation lag. An anisocoria of 0.6 mm or more 4s after switching off the illumination discriminates physiological anisocoria from Horner's syndrome with a sensitivity of 82% and a specificity of 69%. A dilatation speed of 1.1 mm/4 s shows the same ability to differentiate in anisocoria and does not provide any better results. Because of the good correlation between post-cocaine anisocoria and anisocoria after 4 s in darkness, photographic or videographic measurements of the pupillary dilatation lag may complete or in some cases even replace cocaine testing.

Adolescent↗
PubMed1995

[Photographic pupil diagnosis in Horner syndrome].

In cases of miosis without other clinical signs and not contributory medical history it is often hard to differentiate Horner's syndrome. In these cases the pharmacological testing with cocaine eye drops is a well established and validated method. The physiological testing, i.e. the detection and measurement of a dilatation lag in Horner's syndrome, is not so common. For this reason we measured the dilatation of pupils in 22 Horner's syndromes and 16 physiological anisocorias to find limit ("cut off") values. We used flash photography and a commercial available camcorder and took photos in bright light (400 cd/m2) as well as 4 and 15 seconds after cessation of light stimulus in darkness. An anisocoria after 4 seconds of darkness greater than 0.6 mm distinguishes both groups with a sensitivity of 82% and a specifity of 69%. A dilatation speed of the smaller pupil during the first 4 seconds of darkness lower than 1.1 mm/4 sec is also a good threshold value. Because of the additional good correlation of these parameters to the anisocoria after cocaine the photographic methods are at least a supplement to pharmacological testing with cocaine, which is sometimes equivocal and always delays the localizing hydroxyamphetamine test. The advantage of using a camcorder is the immediate evaluation on a TV screen. Because of the similar price it is more useful to buy an infrared camera to perform real pupillography. Because of the missing possibility of magnification we prefer the evaluation of slides instead of Polaroid flash photographs.

Adolescent↗