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Biomedical subjects

A Klein

Publications and source records attributed to A Klein.

At least 181 records · Page 10Linked to original sources
PubMed1996

Purification of autocrine growth factor from conditioned medium of rat sarcoma (XC) cells.

Transformation of rat cells by Rous sarcoma virus(es) induced the release of growth factors into serum-free conditioned media. An PR-RSV-transformed rat cell line, XC, produced and released polypeptide factors which promote anchorage-dependent and anchorage-independent growth of XC cells. One of the autocrine factors of XC cells was purified to homogeneity by four-step procedure: ultrafiltration, ion-exchange chromatography on MonoS, reverse-phase chromatography on Spherisorb ODS2 and gel filtration on Superose 12. The factor gave a single band on SDS-electrophoresis on polyacrylamide gel and was assumed to have a molecular weight of 16 kDa. The factor is a potent mitogen for XC cells; half-maximal stimulation of DNA synthesis was achieved at a concentration of 0.8 ng/ml. The peptide is probably one of the family of EGF-like heparin-binding growth factors.

Animals↗
PubMed1996

Liver transplantation for alcoholic liver disease.

UNLABELLED: Orthotopic liver transplantation (OLT) for individuals with alcoholic liver disease (ALD) remains controversial. This review was designed to evaluate the survival, recidivism, and rehabilitation of the alcoholic liver transplant recipient in a single transplant center. METHODS: Between 10/86 and 11/92 203 liver transplants were performed in 179 patients. In 42 patients (23%) the primary etiologic diagnosis was ALD (36 males, 6 females, median age 47 yr). All ALD patients were evaluated preoperatively by social service, psychiatry, and medical psychology, in addition to hepatology and transplant surgery. A minimum abstinence period of 3-6 months was encouraged, although exceptions were made for cases of extreme medical urgency in which a good prognosis for abstinence was predicted. RESULTS: In OLT recipients with ALD, actuarial survival at 1, 2, and 3 yr was 74%, 71%, and 71%, respectively, compared to 71%, 71%, and 69% for all OLT recipients. One- and two-year survival was 85% in the most recently transplanted 86 patients, 20 of whom (23%) had ALD with 1- and 2-yr survival of 84% (N.S.). Recidivism was monitored postoperatively by interviews with the patient and family, supplemented by random urine and serum toxicology. Of the 29 survivors, 2 (7%) returned temporarily to alcohol use but are presently abstinent. Although none of the ALD patients in this study was able to work prior to OLT, 76% of the survivors at least 4 months post-transplantation were employed. CONCLUSIONS: Although our experience is small, our results suggest that OLT is appropriate therapy for carefully selected patients with end-stage liver failure due to ALD. The multi-disciplinary approach to preoperative evaluation of the alcoholic liver transplant candidate is effective in determining those patients committed to abstinence after a successful transplant.

Actuarial Analysis↗
PubMed1995

Molecular cloning and functional expression in E. coli of a novel plant enzyme mediating zeta-carotene desaturation.

We have cloned a cDNA from the plant Capsicum annuum which encodes a novel enzyme mediating the dehydrogenation of zeta-carotene and neurosporene to lycopene when expressed in E. coli cells accumulating zeta-carotene or neurosporene. This enzyme is unable to dehydrogenate either phytoene or lycopene. The deduced amino acid sequence suggests that this cDNA encodes a polypeptide whose mature size is ca. 59 kDa and which is synthesized as a precursor with a NH2-terminal extension resembling transit peptides for plastid targeting. Sequence comparison reveals 33-35% similarity with previously cloned plant or cyanobacterial phytoene desaturases. In contrast, only limited sequence similarity is found with a zeta-carotene desaturase from the cyanobacterium Anabaena.

Amino Acid Sequence↗
PubMed1995

Use of the Escherichia coli uidA gene as a reporter in Methanococcus voltae for the analysis of the regulatory function of the intergenic region between the operons encoding selenium-free hydrogenases.

The Escherichia coli beta-glucuronidase gene uidA was linked to a region of the Methanococcus voltae genome containing the putative promoter of a gene for a DNA-binding protein and introduced into the M. voltae chromosome. It was found that the enzyme was expressed in the cells in easily measurable amounts. The reporter gene was then placed under the control of the intergenic region found between two divergently transcribed gene groups encoding selenium-free hydrogenases, which are measurably transcribed only after selenium depletion. This region is supposed not only to contain the divergent promoters governing the transcription of the hydrogenase genes but also cis regulatory elements necessary for the negative transcriptional regulation in which selenium is involved. It was shown that the intergenic region functioned as a promoter region for the reporter gene in either orientation. The additional finding that beta-glucuronidase expression was dependent on selenium depletion localizes the cis regulatory elements to the intergenic region between the two hydrogenase operons.

Base Sequence↗
PubMed1995

Structure and chromosomal localization of the mouse oncomodulin gene.

The rat gene encoding oncomodulin (OM), a small calcium-binding protein, is under the control of a solo LTR derived from an endogenous intracisternal A-particle. The latter sequence is the only OM promoter analyzed so far. In order to study cell type-specific OM expression in a species lacking LTR sequences in the OM locus, we initially synthesized an OM cDNA from mouse placenta. By sequencing, we found a 137-bp-long 5'leader region that differed markedly from its rat counterpart but had high similarity to several mouse genomic sequences. Primers specific to this sequence in addition with primers specific for an exon 2/intron 2 sequence were used to screen a mouse ES cell line genomic P1 library. One positive clone contained the whole OM gene, including intron 1 of 25kb and a 5' flanking region of 27 kb lacking an LTR. The region upstream of exon 1 contains no TATA or CCAAT boxes but has a homopurine/homopyrimidine stretch of 102 bp as well as a (CA)22 repeat. The latter sequence is polymorphic and was therefore, used to map the OM gene to the distal end of the long arm of mouse Chromosome (Chr) 5 by interspecific backcross analysis. Additionally we localized the OM gene by in situ hybridization to the region G1-3 on Chr 5, confirming the genetic linkage results. Finally, the OM gene was found to be structurally conserved and to exist in a single copy in mammals.

Amino Acid Sequence↗
PubMed1995

The BCL-1, BCL-2, and BCL-3 oncogenes are involved in chronic lymphocytic leukemia. Detection by fluorescence in situ hybridization.

The putative oncogenes BCL-1, BCL-2, and BCL-3 are commonly rearranged by translocations to the immunoglobulin genes in B-cell malignancies. However, Southern blotting rarely detected their involvement in chronic lymphocytic leukemia (CLL). This discrepancy could stem from some unique features of the oncogenesis of CLL or be due to shortcomings of Southern blotting. We have therefore evaluated the role of fluorescence in situ hybridization (FISH) in the detection of these oncogenes in CLL. Twenty consecutive CLL patients were studied by FISH for the detection of BCL-1, BCL-2, or BCL-3 rearrangement and for the presence of trisomy 12. Selected patients were also evaluated by classical cytogenetic techniques and by Southern blot analysis. Juxtaposition of JH and BCL-1 was demonstrated in 10 (50%), BCL-2 in three (15%), and BCL-3 in four (20%) of the patients. Trisomy 12 was detected by FISH in 11 (55%) patients. The coexistence of trisomy 12 and translocation of the BCL-1 oncogene was common. Three of the patients had chromosomal aberrations compatible with those detected by FISH. In contrast, in none of the five patients selected by their positive FISH findings was a rearrangement demonstrated by Southern blotting. We conclude that FISH is a sensitive method for the detection of oncogene involvement in CLL. Mainly BCL-1, but also BCL-2 and BCL-3, are commonly translocated to the immunoglobulin heavy chain locus on chromosome 14. These translocations are often associated with trisomy 12. These findings indicate that the BCL oncogenes are commonly involved in CLL and lend support to the multi-hit theory of cancer development.

Aged↗
PubMed1995

Metabolism of cyclic carotenoids: a model for the alteration of this biosynthetic pathway in Capsicum annuum chromoplasts.

The biosynthetic pathway of cyclic carotenoid is known to be quantitatively and qualitatively different in the non-green plastids of Capsicum annuum fruits compared with chloroplasts. Here, the cloning is described of a novel cDNA from this organism, which encodes an enzyme catalyzing the cyclization of lycopene to beta-carotene when expressed in Escherichia coli. The corresponding gene is constitutively expressed during fruit development. Significant amino acid sequence identity was observed between this enzyme and capsanthin/capsorubin synthase which is involved in the synthesis of the species-specific red carotenoids of C. annuum fruits. The latter enzyme was found also to possess a lycopene beta-cyclase activity when expressed in E. coli. A model is proposed for the origin of the capsanthin/capsorubin synthase gene and the role of this enzyme, together with the newly cloned lycopene cyclase, in the specific re-channeling of linear carotenoids into beta-cyclic carotenoids in C. annuum ripening fruits.

Amino Acid Sequence↗
PubMed1995

Monoclonal lymphocyte proliferation and bcl-2 rearrangement in essential mixed cryoglobulinaemia.

A patient with essential mixed cryoglobulinaemia (EMC) type II and hepatitis C virus (HCV) infection, in whom immunophenotypic and genotypic studies demonstrated a clonal proliferation of B lymphocytes, is described. Fluorescent in situ hybridization with probes to Ig heavy chain gene and to the oncogene bcl-2 demonstrated a translocation of bcl-2 to the immunoglobulin heavy chain locus on chromosome 14. A sharp rise in the level of the monoclonal IgM was associated with a second genetic aberration [t(8:22) (q24:q11)]. No other clinical evidence of disease progression could be demonstrated. Low grade lymphoproliferative disorder with typical cytogenetic abnormalities developed on the background of EMC and HCV. Clinical progression was associated with a second genetic abnormality involving the myc oncogene. It is possible that HCV chronic infection may indirectly influence oncogenes associated with lymphoma.

Adult↗
PubMed1995

Insertional Mutations in the Hydrogenase vhc and frc Operons Encoding Selenium-Free Hydrogenases in Methanococcus voltae.

Methanococcus voltae, which contains four different gene groups that encode [NiFe]-hydrogenases, was transformed with integration vectors to achieve polar inactivation of two of the four hydrogenase operons that encode the selenium-free enzymes Vhc and Frc. Transformants which were selected by their acquired puromycin resistance showed site-specific insertions in either the vhc or frc operon by single crossover events. Southern hybridization revealed tandem integrations of whole vectors in the vhc operon, whereas only one vector copy was found in the frc operon. Northern (RNA) hybridizations showed a pac transcript of defined size, indicating strong termination in front of the hydrogenase genes downstream. In spite of the apparent abolition of expression of selenium-free hydrogenases through these polar insertions, they were not lethal to cells upon growth in selenium-deprived minimal medium, which we had previously shown to strongly induce transcription of the respective operons in M. voltae. Instead, like wild-type control cultures, transformants responded to selenium deprivation only with a reduction in growth rate. We conclude that loss of the potential to express a selenium-free hydrogenase can nevertheless be balanced by very small amounts of selenium hydrogenases under laboratory conditions in which the hydrogen supply is not likely to be a limiting growth factor.

Journal Article↗
PubMed1995

ERA-experiment "Space Biochemistry".

The general goal of the experiment was to study the response of anhydrobiotic (metabolically dormant) microorganisms (spores of Bacillus subtilis, cells of Deinococcus radiodurans, conidia of Aspergillus species) and cellular constituents (plasmid DNA, proteins, purple membranes, amino acids, urea) to the extremely dehydrating conditions of open space, in some cases in combination with irradiation by solar UV-light. Methods of investigation included viability tests, analysis of DNA damages (strand breaks, DNA-protein cross-links) and analysis of chemical effects by spectroscopic, electrophoretic and chromatographic methods. The decrease in viability of the microorganisms was as expected from simulation experiments in the laboratory. Accordingly, it could be correlated with the increase in DNA damages. The purple membranes, amino acids and urea were not measurably effected by the dehydrating condition of open space (in the dark). Plasmid DNA, however, suffered a significant amount of strand breaks under these conditions. The response of these biomolecules to high fluences of short wavelength solar UV-light is very complex. Only a brief survey can be given in this paper. The data on the relatively good survival of some of the microorganisms call for strict observance of COSPAR Planetary Protection Regulations during interplanetary space missions.

Argon↗
PubMed1995

The role of lymphocytes in the neutrophil migration induced by ovalbumin in immunized rats.

In the present study, we investigated the role of resident cells in the neutrophil migration induced by ovalbumin (OVA) in immunized rats. OVA administration induced dose-dependent neutrophil migration, which was inhibited by pretreating the animals with dexamethasone, but not with indomethacin or BW 70C. Lymphocytes, but not macrophages or mast cells, obtained from sensitized animals and stimulated in vitro with OVA released a factor that induced neutrophil migration in vivo and in vitro. Both the release of this factor in vitro and the neutrophil migration induced in vivo were inhibited by dexamethasone, thus explaining the inhibitory effect of glucocorticoids on the neutrophil migration induced by OVA in immunized animals. Neither indomethacin nor BW 70C had any such effect. The fact that actinomycin D also inhibited the release of the factor from OVA-stimulated lymphocytes suggests that this substance is of a proteinaceous nature. The importance of lymphocytes for neutrophil recruitment in OVA-immunized rats was supported by the fact that homologous lymphocyte transfer into air pouches rendered these cavities responsive to OVA. Lymphocytes obtained from naive rats and stimulated with the lectins concanavalin A (Con A) or phytohaemagglutinin (PHA) were also able to release a factor that induced neutrophil migration in vivo. In vitro incubation of the supernatant from OVA-stimulated lymphocytes with antisera to interleukin-1 beta (IL-1 beta), IL-8 and tumour necrosis factor-alpha (TNF-alpha) did not inhibit the neutrophil chemotactic activity. These data suggest that IL-1 beta, IL-8 and TNF-alpha are not involved in the neutrophil chemotactic activity of the supernatant. Overall, these results indicate the importance of lymphocyte participation in neutrophil recruitment during inflammatory immune reaction, through the release of a neutrophil chemotactic factor different from IL-1 beta, IL-8 and TNF-alpha.

Animals↗
PubMed1995

[Initial experiences with the "0.8 promille regulation in Thüringen].

Blood samples sent in for analysis in 1992 and 1993 showed an increase in the BAC values of offenders in the "driving under the influence" category. At the same time it was found that, proportionally, the number of people whose BAC was below 0.8% had dropped. The same trend could be observed in the "road accident" category. This trend continued throughout 1994. One can therefore assume that the introduction of the "0.8% law" in eastern Germany has brought with it an increase in the level of intoxication of people driving under the influence of alcohol.

Accidents, Traffic↗
PubMed1995

A study of Israeli blood donors, asymptomatic carriers of hepatitis C virus, in relation to liver disease, cryoglobulinemia and transmission.

In order to study the asymptomatic hepatitis C virus (HCV)-positive blood donors in Israel we analyzed their sera for HCV-RNA using the polymerase chain reaction technique. We found that 0.44% of blood donors were anti-HCV positive. Of those who had repeatedly positive anti-HCV, 82% had evidence of HCV-RNA. One-third of them had elevated liver enzymes, but no detectable cryoglobulins were found in their sera. Although HCV-RNA was detected in the majority of the patients, we were unable to demonstrate vertical or horizontal transmission among the family members of our carrier population.

Adult↗
PubMed1995

Increased signals seen in globus pallidus in T1-weighted magnetic resonance imaging in cirrhotics are not suggestive of chronic hepatic encephalopathy.

Increased, symmetrical signals of varying intensity in the globus pallidi on T1-weighted (T1W) images, without corresponding signals on T2-weighted (T2W) images, have been reported previously in chronic hepatic failure. It has been suggested that these signals are characteristic of chronic hepatic encephalopathy. To test this hypothesis, we evaluated the relationship of magnetic resonance imaging (MRI) abnormalities with ammonia, albumin, bilirubin, prothrombin time, ascites, clinical encephalopathy, and neuropsychological tests in 46 patients (16 with alcohol-induced cirrhosis and 30 with non-alcohol-induced cirrhosis). T1W signal and cortical atrophy were graded by a neuroradiologist in a blinded fashion. Eleven patients had no T1W signal, 18 had minimal T1W signal, and 17 had high T1W signal. Twenty-five patients had no cortical atrophy, 14 had mild atrophy, and 7 had moderate atrophy. Cortical atrophy was noted more commonly in patients with alcohol-induced liver disease. The neuropsychological tests correlated significantly with albumin, prothrombin time, Child-Pugh's score, clinical encephalopathy, and ammonia. T1W signal and cortical atrophy did not correlate with the neuropsychological tests, clinical encephalopathy, ascites, albumin, prothrombin time, ammonia, or Child-Pugh's score. Patients with high T1W signal showed significant correlation with bilirubin (P < .005). This study suggests that globus pallidus signal in T1W images observed in liver disease are not indicators of chronic hepatic encephalopathy as previously assumed.

Adult↗
PubMed1994

Delta-T-lymphocytosis in a patient with thymoma.

BACKGROUND: Malignant thymoma is composed of neoplastic epithelial cells and small lymphocytes. Rarely, patients also may have peripheral T-lymphocytosis. These lymphocytes have been considered nonneoplastic because of their microscopic appearance and immunophenotype, as well as gene rearrangement studies. METHODS: A 42-year-old man developed lymphocytosis 3 years after the completion of intensive combined chemoradiotherapy protocol for lymphocytic thymoma. These peripheral blood lymphocytes were evaluated phenotypically and genotypically. RESULTS: Immunophenotyping established that the cells were CD3 positive, CD4 negative, CD8 negative, T-cell receptor (TCR)-alpha/beta negative, and TCR-gamma/delta positive. Gene rearrangement studies with TCR-delta probe confirmed the monoclonality of these cells. Chromosome analysis showed deletion of chromosome Y. The clinical course was progressive and had the features of malignant lymphoma. CONCLUSIONS: To the authors' knowledge, this is the first report of a patient with thymoma in whom monoclonal proliferation of T-gamma/delta peripheral blood lymphocytes was confirmed immunophenotypically and genotypically. These monoclonal TCR-gamma/delta lymphocytes may belong to the malignant clone of the thymoma; however, the possibility that they represent an evolution of a second lymphatic malignancy cannot be excluded.

Adult↗