PubMed Health⌕ Search

Biomedical subjects

G Scherer

Publications and source records attributed to G Scherer.

At least 73 records · Page 4Linked to original sources
PubMed1996

Translocation breakpoints in three patients with campomelic dysplasia and autosomal sex reversal map more than 130 kb from SOX9.

Campomelic dysplasia (CMPD1) and autosomal XY sex reversal (SRA1) are caused by mutations in the SRY-related gene SOX9 on 17q. Unexpectedly, the 17q breakpoints in four CMPD1 translocation cases previously analyzed by us and others map 50 kb or more from SOX9. Here, we present clinical, cytogenetic, and molecular data from a new CMPD1/SRA1 patient with t(6;17)(q14;q24). Fluorescence in situ hybridization has shown that the 17q breakpoint in this case maps to the same region as the breakpoints in the other translocation cases, at least 130 kb from SOX9. Likewise, the breakpoints in two of the previously described cases also map more than 130 kb and, as shown by pulsed field gel electrophoresis analysis, at most 400 kb or 690 kb from SOX9. By using a SOX9 coding sequence polymorphism, expression of both SOX9 alleles has been demonstrated by the reverse transcriptase polymerase chain reaction in lymphoblastoid cells from one of the translocation cases.

Alleles↗
PubMed1996

Rbt (Rabo torcido), a new mouse skeletal mutation involved in anteroposterior patterning of the axial skeleton, maps close to the Ts (tail-short) locus and distal to the Sox9 locus on chromosome 11.

Rbt (Rabo torcido) is a new semidominant mouse mutant with a variety of skeletal abnormalities. Heterozygous Rbt mutants display homeotic anteroposterior patterning problems along the axial skeleton that resemble Polycomb group and trithorax gene mutations. In addition, the Rbt mutant displays strong similarities to the phenotype observed in Ts (Tail-short), indicating also a homeotically transformed phenotype in these mice. We have mapped the Rbt locus to an interval of approximately 6 cM on mouse Chromosome (Chr) 11 between microsatellite markers D11Mit128 and D11Mit103. The Ts locus was mapped within a shorter interval of approximately 3 cM between D11Mit128 and D11Mit203. This indicates that Rbt and Ts may be allelic mutations. Sox9, the human homolog of which is responsible for the skeletal malformation syndrome campomelic dysplasia, was mapped proximal to D11Mit128. It is, therefore, unlikely that Ts and Rbt are mouse models for this human skeletal disorder.

Animals↗
PubMed1996

Sex reversal by loss of the C-terminal transactivation domain of human SOX9.

Haploinsufficiency for SOX9 has recently been identified as the cause for both campomelic dysplasia (CD), a human skeletal malformation syndrome, and the associated autosomal XY sex reversal. SOX9 contains a putative DNA-binding motif known as the high-mobility group (HMG) domain characterizing a whole class of transcription factors. We show in cell transfection experiments that SOX9 can transactivate transcription from a reporter plasmid through the motif AACAAAG, a sequence recognized by other HMG domain transcription factors. By fusing all or part of SOX9 to the DNA-binding domain of yeast GAL4, the transactivating function was mapped to a transcription activation (TA) domain at the C terminus of SOX9. This non-acidic TA domain is evolutionarily conserved and rich in proline, glutamine and serine. With one exception, all SOX9 nonsense and frame shift mutations described so far in CD/sex reversal patients lead to truncation of the TA domain, suggesting that impairment of gonadal and skeletal development in these cases results, at least in part, from loss of transactivation of genes downstream of SOX9.

Amino Acid Sequence↗
PubMed1996

SOX20, a new member of the SOX gene family, is located on chromosome 17p13.

SOX genes share a high sequence identity with the HMG box present in the testis determining gene SRY. We have identified a HMG box-like sequence motif on six contiguous cosmids, which cross-hybridize to a SOX9 cDNA probe. A data base search revealed a high similarity of the deduced amino acid sequence to the human SOX12 and the murine Sox16 HMG domains. The cosmids were assigned to chromosome 17p13 by FISH analysis.

Amino Acid Sequence↗
PubMed1996

[Detection of nicotine in prehistorical skeletal remains of South China].

Human remains from excavation sites in southern China, dated from 100 to 10,000 years, were investigated for nicotine. The nicotine concentrations were measured by radioimmunoassay. Consequently, the values measured represent the sum of nicotine and its metabolites. Positive results were observed in 25.9% (mean values of all samples). The concentrations ranged from 11.8 to 474.2 ng/g sample. From the excavation sites with the highest number of individuals, Chongtong (18 individuals) were 38.9%, and from the site Leigund (21 individuals) were 28.6% from the samples nicotine positive. The highest level with 474.2 ng/g nicotine was found in a sample dated 100 years. It is possible, that this individual was smoker. In addition the samples were investigated also by gas chromatography/mass spectrometry. The GC/MS indicated the presence of nicotine and its primary metabolite, cotinine. The presence of cotinine points out the assumption that nicotine was used antemortem. The detection of unchanged nicotine indicates that nicotine remained present in bones up centuries.

Bone and Bones↗
PubMed1995

Kinetic analysis of cyclophilin-catalyzed prolyl cis/trans isomerization by dynamic NMR spectroscopy.

To investigate the kinetics of the prolyl peptide bond cis/trans isomerization of N-succinyl-Ala-Phe-Pro-Phe-(4)-nitroanilide catalyzed by peptidyl prolyl cis/trans isomerases (PPIases), one-dimensional dynamic 1H NMR spectroscopy was employed. To this end line shape analyses of proton signals were performed at various concentrations of both cytosolic porcine kidney cyclophilin (Cyp18) and peptide substrate. Catalysis of the cis/trans isomerization by Cyp18 is best described by a four-site exchange model, where the four sites represent the cis and trans isomers free in solution and bound to the enzyme. Combination of dynamic NMR spectroscopy with the classical protease-coupled PPIase assay allowed determination of the complete set of the microscopic rate constants describing the four site exchange model. The comparison of the rate constants of cis-->trans isomerization of the peptide free in solution and bound to cyclophilin yields an acceleration factor of 3.5 x 10(5). Dissociation of the Michaelis complexes are of the same order of magnitude as the isomerization rates on the enzyme. Therefore, all microscopic rate constants contribute to the steady state parameters. For the first time, the kcat (620 s-1) and KM (220 microM) value for the trans isomer in addition to the values of the cis isomer (kcat = 680 s-1, KM = 80 microM) could be determined under reversible conditions at pH 6.0 and 10 degrees C. The affinity of Cyp18 for the cis isomer is 4 times higher than for the trans isomer. This results in a shift of the cis/trans equilibrium toward the cis isomer.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Isomerases↗
PubMed1995

Determination of urinary trans,trans-muconic acid by gas chromatography-mass spectrometry.

A sensitive and specific method for the determination of trans,trans-muconic acid (t,t-MA) in urine is described. After clean-up on an anion-exchange cartridge, t,t-MA was derivatized with BF3-methanol to the dimethyl ester and analyzed by gas chromatography-mass spectrometry (GC-MS), with 2-bromohexanoic acid as an internal standard. The limit of detection was 0.01 mg/l, the coefficient of variation for duplicate analysis in a series of urine samples (n = 50) was 2.6% and the recovery rate ranged from 93.3 to 106.3%. The between-day and within-day precision for the analysis were 7.4 and 14.6%, respectively. The method was applied to the determination of t,t-MA in urine samples from smokers and non-smokers. The mean concentration of t,t-MA in urine of 10 smokers was 0.09 +/- 0.04 mg/g creatinine and was significantly (p = 0.012) higher than that found in urine of 10 non-smokers (0.05 +/- 0.02 mg/g creatinine). In contrast to the results obtained with the commonly used high-performance liquid chromatographic ultraviolet detection (HPLC-UV) methods, no interference between t,t-MA and other urinary compounds was found. This GC-MS method is both specific and sensitive for biomonitoring of low environmental benzene exposure.

Adult↗
PubMed1995

Self-assessment of angles of strabismus with photographic Purkinje I and IV reflection pattern evaluation.

BACKGROUND: Accurate assessment of the angle of strabismus, e.g. of variable angles of strabismus, is crucial in preoperative patient management and is usually performed in a clinical environment. Objective assessment by patients themselves, under everyday conditions, could contribute to a better preoperative work-up. A new objective evaluation procedure for the measurement of manifest angles of strabismus for near and distance fixation by the patient himself is presented. METHODS: To account for the modified experimental setup used for the self-assessment, an amended computation procedure of Purkinje reflection pattern evaluation was developed. For measurement, patients and controls placed their head on a head/chin rest and fixated at 33 cm or 4 m distance in primary position. A reflex camera and three photo flash units were positioned on a special frame underneath the visual axis and in front of the subject so that both eyes could be photographed simultaneously. The camera's remote shutter control was released together with the photo flash units by the properly fixating subject. The angles of strabismus were obtained from the series of pictures through later evaluation of the Purkinje I and IV reflection patterns recorded in the photographs of the eyes. RESULTS: Measurements of the ocular alignment in two control groups and in a group of strabismic subjects showed satisfactory accuracy of the "self-assessment" method compared to "standard" Purkinje reflection pattern evaluation and orthoptic measurements of the angle of strabismus. CONCLUSION: The modified "self-assessment" method can be used for the objective recording of angles of strabismus as needed in the preoperative work-up of patients with variable angles of strabismus, over prolonged periods of time, and outside a clinical setting.

Adolescent↗
PubMed1995

[The sonographic and computed radiographic findings in perigraft reactions after the surgical implantation of vascular prostheses].

Between January 1988 and January 1994, 24 patients with heterologous vascular bypasses were examined with suspected diagnosis of a perigraft reaction (PGR). All patients were subjected to ultrasound and CT. PGR ist defined as a sterile inflammation along the course of a vascular prosthesis. The typical clinical presentation is a fluctuating tumour with a localised painless swelling. In all cases liquid formations could be confirmed by diagnostic imaging procedures; signs of infection could be excluded. The synopsis of the clinical presentation, the time interval after implantation of the prosthetic material and the signs of sonography and CT can reliably exclude infection of the prosthesis and confirm the diagnosis of a PGR.

Aged↗
PubMed1995

The human protein kinase gene PKX1 on Xp22.3 displays Xp/Yp homology and is a site of chromosomal instability.

We have isolated a gene, PKX1, by virtue of its position within the candidate region for chondrodysplasia punctata in Xp22.3. Although data from one patient render it unlikely that PKX1 is the CDPX gene, this gene shows several interesting features. First, PKX1 appears to encode a novel type of human protein kinase that is related to the catalytic subunit of cAMP-dependent protein kinases and has striking homology to the DC2 protein kinase from Drosophila melanogaster. Second, PKX1 is part of a family of at least four genes or pseudogenes, of which three map to the human sex chromosomes. In contrast to all other genes from the X-specific region of Xp22.3, PKX1 has a homologue on Yp rather than Yq. This is intriguing as it indicates that the single pericentric inversion event hypothesized to have occurred during primate evolution is not sufficient to explain the present X/Y-homology pattern of Xp22.3. Third, we have characterized patients with different chromosomal rearrangements in Xp22.3 or Yp and show that a high proportion of these have occurred within the PKX1 locus. This suggests that the PKX1 gene, besides harbouring a previously described hot-spot for illegitimate Xp/Yp-recombination, contains additional sequences predisposing to chromosomal breakage events.

Amino Acid Sequence↗
PubMed1995

Determination of low level exposure to volatile aromatic hydrocarbons and genotoxic effects in workers at a styrene plant.

OBJECTIVES: Low exposures to volatile aromatic hydrocarbons and cytogenetic effects in peripheral white blood cells were determined in 25 healthy workers employed in different areas of a styrene production plant in the former German Democratic Republic. The results were compared with 25 healthy unexposed controls (matched for age and sex) employed in the same company. METHODS: The concentrations of aromatic hydrocarbons determined from active air sampling in all areas of the factory (styrene: 73-3540 micrograms/m3 (< 0.01-0.83 ppm); ethylbenzene 365-2340 micrograms/m3 (0.08-0.53 ppm); benzene 73-3540 micrograms/m3 ( < 0.02-1.11 ppm); toluene 54-2960 micrograms/m3 (0.01-0.78 ppm); xylenes 12-94 micrograms/m3 ( < 0.01-0.02 ppm)) were considerably lower than in the pump house ( > 4000 micrograms/m3 styrene, ethylbenzene, benzene, and toluene; > 500 micrograms/m3 xylenes), which was only intermittently occupied for short periods. Passive personal monitoring, biomonitoring of exhaled air and metabolites (mandelic, phenylglyoxylic, trans, trans-muconic, hippuric, o-, m- and p-methylhippuric acids, and phenol) in urine samples collected before and after an eight hour working shift was used to assess individual exposure. Questionnaires and examination of company records showed that the historical exposure was far higher than that measured. Genotoxic monitoring was performed by nuclease P1-enhanced 32P-postlabelling of DNA adducts in peripheral blood monocytes, and DNA single strand breaks, sister chromatid exchange, and micronuclei in lymphocytes. The content of kinetochores in the micronuclei was determined by immunofluorescence with specific antibodies from the serum of CREST patients. RESULTS: No genotoxic effects related to exposure were detected by DNA adducts or DNA single strand breaks and sister chromatid exchange. The only effect related to exposure was an increase in kinetochore positive micronuclei in peripheral lymphocytes; the frequency of total micronuclei in peripheral lymphocytes did not change. Smoking was confirmed by measurement of plasma cotinine, and no confounding effect was found on any of the cytogenetic variables. CONCLUSIONS: Low occupational exposure to styrene, benzene, and ethylbenzene did not induce alterations of genotoxicological variables except kinetochore positive micronuclei. This is the first reported use of the CREST technique for an in vivo study in occupational toxicology, which thus could serve as a valuable and sensitive technique for toxicogenic monitoring.

Adult↗
PubMed1995

[Computerized tomography diagnosis of a secondary extramedullary situated, non-secreting plasmacytoma of the right plica ventricularis].

We report the case of a 62-year-old male patient with an extramedullary non-secreting plasmacytoma of the right plica ventricularis. Although his skeletal lesions remained stable, the patient developed hoarseness. This was interpreted as mycotic laryngitis and computed tomography showed a tumor of the right plica ventricularis. Differential diagnosis included neoplasms of the larynx, thyroid gland or a lymphoma. After biopsy, however, histology revealed the rare diagnosis of a secondary extramedullary non-secreting plasmacytoma.

Biopsy, Needle↗
PubMed1995

Two novel SRY missense mutations reducing DNA binding identified in XY females and their mosaic fathers.

Two novel mutations in the sex-determining gene SRY were identified by screening DNA from 30 sex-reversed XY females by using the SSCP assay. Both point mutations lead to an amino acid substitution in the DNA-binding high-mobility-group domain of the SRY protein. The first mutation, changing a serine at position 91 to glycine, was found in a sporadic case. The second mutation, leading to replacement of a highly conserved proline at position 125 with leucine, is shared by three members of the same family, two sisters and a half sister having the same father. The mutant SRY proteins showed reduced DNA-binding ability in a gel-shift assay. Analysis of lymphocyte DNA from the respective fathers revealed that they carry both the wild-type and the mutant version of the SRY gene. The fact that both fathers transmitted the mutant SRY copy to their offspring implies that they are mosaic for the SRY gene in testis as well as in blood, as a result of a mutation during early embryonic development.

Adolescent↗
PubMed1994

Autosomal sex reversal and campomelic dysplasia are caused by mutations in and around the SRY-related gene SOX9.

A human autosomal XY sex reversal locus, SRA1, associated with the skeletal malformation syndrome campomelic dysplasia (CMPD1), has been placed at distal 17q. The SOX9 gene, a positional candidate from the chromosomal location and expression pattern reported for mouse Sox9, was isolated and characterized. SOX9 encodes a putative transcription factor structurally related to the testis-determining factor SRY and is expressed in many adult tissues, and in fetal testis and skeletal tissue. Inactivating mutations on one SOX9 allele identified in nontranslocation CMPD1-SRA1 cases point to haploinsufficiency for SOX9 as the cause for both campomelic dysplasia and autosomal XY sex reversal. The 17q breakpoints in three CMPD1 translocation cases map 50 kb or more from SOX9.

Amino Acid Sequence↗
PubMed1994

Pituitary and adrenal hormone responses to pharmacological, physical, and psychological stimulation in habitual smokers and nonsmokers.

Hormone responses to injection of corticotropin-releasing hormone following bicycle ergometry and psychological stress were studied in ten habitual smokers and ten nonsmokers. Compared to injection of saline, significant increases were found in adrenocorticotropin, prolactin, growth hormone, total serum cortisol, and salivary cortisol under all three stimulations except for salivary cortisol under ergometry. Furthermore, the smokers showed significant elevations of all five hormones investigated following the smoking of two cigarettes of the subject's preferred brand. Comparisons of hormone responses between smokers and nonsmokers revealed a general trend towards stronger responses in nonsmokers. However, due to the small number of subjects investigated and considerable variation in the individual hormone responses these differences reached statistical significance only for growth hormone responses following ergometry and salivary cortisol responses after psychological stress. In addition, the circadian rhythm of salivary cortisol was measured on two occasions between 9 a.m. and 9 p.m. in the subject's natural environment. The typical circadian pattern of decreasing cortisol levels was observed, with no significant differences between smokers and nonsmokers. We conclude that chronic nicotine consumption may lead to lower responses of multiple hormones not only to nicotine but to a variety of stimuli, and that these alterations do not necessarily affect unstimulated circadian profiles of free cortisol.

Adrenocorticotropic Hormone↗
PubMed1994

Metabolic effects of nicotine on human adipose tissue in organ culture.

Fragments of human adipose tissue were maintained in culture for 1 week in a medium containing 1 mU/ml insulin and 100 ng/ml dexamethasone. Under these conditions lipoprotein lipase activity was present in human adipose tissue fragments which converted [14C]glucose to 14CO2 and [14C]triglyceride. Both metabolic parameters studied were affected by human tumor necrosis factor and brefeldin A. When fragments of human adipose tissue after 1 week in culture were incubated with nicotine tartrate for 20 h, a slight but significant increase in lipoprotein lipase activity was observed, and an increased conversion of [14C]glucose to 14CO2 and [14C]triglyceride occurred. Nicotine was taken up by human adipose tissue, but no conversion to cotinine was observed. Our data demonstrate a direct effect of nicotine on human adipose tissue metabolism. Furthermore, it is suggested that weight loss in smokers is a multifactorial phenomenon, and one of the important factors to be considered is the direct effect of nicotine within the tissue.

Adipose Tissue↗