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H Meisner

Publications and source records attributed to H Meisner.

At least 55 records · Page 3Linked to original sources
PubMed1989

Cloning and characterization of a cDNA encoding the beta subunit of human casein kinase II.

Previous studies [Summercorn et al. (1987) Proc. Natl. Acad. Sci. U.S.A. 84, 8834-8838; Klarlung & Czech (1988) J. Biol. Chem. 263, 15872-15875] have indicated that Balb/c 3T3 cells and 3T3-L1 adipocytes incubated with insulin show increased casein kinase II activity within minutes, implicating this serine/threonine kinase as an early step in an insulin signaling pathway. We recently reported the isolation of a cDNA encoding an alpha subunit of human casein kinase II [Meisner et al. (1989) Biochemistry 28, 4072-4076] as an initial step toward examining the regulation of this enzyme. We now describe a HepG2 cell casein kinase II beta subunit cDNA of 2.57 kb containing 96 bases of 5' untranslated sequence, 645 bases of open reading frame, and 1832 bases of 3' untranslated sequence with two polyadenylation consensus signal sequences and two poly(A) stretches. The open reading frame of the human beta subunit cDNA was 77% and 87% identical with the Drosophila sequence at the nucleotide and amino acid levels, respectively, and 99% identical with the bovine amino acid sequence. RNA analysis of HepG2 cell RNA utilizing HepG2 beta subunit cDNA fragments as probes revealed one major band migrating at 1.2 kb and two minor bands migrating at 3.0 and 4.2 kb. Results from DNA analysis of HepG2 genomic DNA, consistent with results utilizing Drosophila genomic DNA, suggest the presence of a single gene for the beta subunit of casein kinase II.

Amino Acid Sequence↗
PubMed1989

Molecular cloning of the human casein kinase II alpha subunit.

A human cDNA encoding the alpha subunit of casein kinase II and a partial cDNA encoding the rat homologue were isolated by using a Drosophila casein kinase II cDNA probe. The 2.2-kb human cDNA contains a 1.2-kb open reading frame, 150 nucleotides of 5' leader, and 850 nucleotides of 3' noncoding region. Except for the first 7 deduced amino acids that are missing in the rat cDNA, the 328 amino acids beginning with the amino terminus are identical between human and rat. The Drosophila enzyme sequence is 90% identical with the human casein kinase II sequence, and there is only a single amino acid difference between the published partial bovine sequence and the human sequence. In addition, the C-terminus of the human cDNA has an extra 53 amino acids not present in Drosophila. Northern analysis of rat and human RNA showed predominant bands of 5.5, 3.1, and 1.8 kb. In rat tissues, brain and spleen had the highest levels of casein kinase II alpha subunit specific RNA, while skeletal muscle showed the lowest. Southern analysis of human cultured cell and tissue genomic DNA using the full-length cDNA probe revealed two bands with restriction enzymes that have no recognition sites within the cDNA and three to six bands with enzymes having single internal sites. These results are consistent with the possibility that two genes encode the alpha subunits.

Amino Acid Sequence↗
PubMed1988

Renal enzyme activities in experimental ochratoxin A-induced porcine nephropathy: diagnostic potential of phosphoenolpyruvate carboxykinase and gamma-glutamyl transpeptidase activity.

Enzyme activities have been measured in needle biopsies from kidneys of pigs fed 1 ppm or 0.2 ppm of ochratoxin A for 1-5 wks. After feeding 1 ppm toxin for 1 wk, the activity of cytosolic phosphoenolpyruvate carboxykinase (PEPCK) was decreased by 40% and remained inhibited until the termination of the experiment (5 wk). The activity of gamma-glutamyl transpeptidase, a brush-border enzyme found in the proximal tubules, was reduced to a similar degree and remained inhibited. The activities of hexokinase, a cytosolic enzyme of general distribution in the nephron, and phosphate-dependent glutaminase, a distal tubule enzyme, were not affected. The biopsy results were confirmed by measurements in renal slices taken at the termination of the experiment, except that biopsy samples showed more variation in enzyme activity and a lower PEPCK activity. A guinea pig antibody against the cytosolic form of PEPCK was used to demonstrate that the mitochondrial form of the enzyme, which accounts for a considerable part of the total cellular activity, was not affected by ochratoxin A. When mitochondrial PEPCK activity present in the cytosolic fraction was accounted for, ochratoxin A was found to reduce PEPCK activity by 70-80%. The increase of ochratoxin A exposure from zero through 0.2 ppm to 1 ppm, which resulted in dose-dependent activity decrease of PEPCK and gamma-glutamyl transpeptidase, was accompanied by dose-dependent decrease of renal function, as measured by a reduction of maximal tubular excretion of para-aminohippurate per clearance of inulin (TmPAH/CIn) and an increase in glucose excretion. This suggest that these enzymes are sensitive indicators of ochratoxin A-induced porcine nephropathy. Assuming that porcine nephropathy represents a valid model of endemic (Balkan) nephropathy in humans, the measurement of cytosolic PEPCK and gamma-glutamyl transpeptidase activity in the kidney could be a sensitive test for ochratoxin A-induced disease in humans.

Animals↗
PubMed1987

Regulation of transferrin receptor cycling by protein kinase C is independent of receptor phosphorylation at serine 24 in Swiss 3T3 fibroblasts.

Treatment of Swiss 3T3 fibroblasts with tumor-promoting phorbol diester or with platelet-derived growth factor caused the phosphorylation of the transferrin receptor by protein kinase C (Ca2+/phospholipid-dependent enzyme) at serine 24 and increased the cell surface expression of the transferrin receptor. The hypothesis that the regulation of transferrin receptor cycling by protein kinase C is causally related to the phosphorylation of the receptor at serine 24 was critically tested. Site-directed mutagenesis of the human transferrin receptor cDNA was used to substitute serine 24 with threonine or alanine residues in order to create phosphorylation defective receptors. Wild-type and mutated transferrin receptors were expressed in Swiss 3T3 fibroblasts using the retrovirus vector pZipNeoSV (X). These receptors were functionally active and caused the receptor-mediated endocytosis of diferric transferrin. Incubation of the fibroblasts with phorbol diester caused the phosphorylation of the wild-type (Ser-24) human transferrin receptor, but this treatment did not result in the phosphorylation of the mutated (Ala-24 and Thr-24) receptors. The cycling of the phosphorylation defective receptors was regulated by phorbol diester and platelet-derived growth factor in a manner similar to that observed for the wild-type receptor. We conclude that the regulation of transferrin receptor cycling by protein kinase C is independent of receptor phosphorylation at serine 24 in Swiss 3T3 fibroblasts.

Animals↗
PubMed1986

Androgen induction of messenger RNA concentrations in mouse kidney is posttranscriptional.

The concentrations of several mRNAs in mouse kidney increase in response to testosterone. To determine if the increases are generated at the level of gene transcription, we have assayed transcription rates for several androgen-inducible mRNAs in kidney nuclei in vitro. No significant changes were found in the synthesis of three mRNAs whose concentrations increase 10-20-fold during testosterone treatment. Kinetic analysis of changes in transcript levels after testosterone administration and withdrawal suggests that mRNA stabilization is a major factor in the inductions. Thus, the androgen-mediated induction of these kidney mRNAs is generated predominantly at the posttranscriptional level.

Animals↗
PubMed1986

Changes of renal mRNA species abundance by ochratoxin A.

Ochratoxin A is a nephrotoxin produced by certain species of Aspergillus and Penicillium. We have found previously that renal but not hepatic P-enolpyruvate carboxykinase, and the mRNA for this enzyme, are rapidly decreased in rats and swine fed 0.1 to 1 mg/kg body weight for a few days. In the present study, we isolated kidney mRNA from rats fed ochratoxin A for 2-5 days. By screening a rat kidney cDNA library with [32P]RNA, we have identified several renal mRNAs whose concentration is changed within 2 days by the toxin. The transcription rate of each mRNA was measured in nuclei isolated from kidneys of rats fed ochratoxin A. The incorporation of [32P]UMP into P-enolpyruvate carboxykinase mRNA and the synthesis of other RNAs were not affected. Therefore, the toxin changes mRNA abundance at the post-transcriptional level.

Animals↗
PubMed1986

Interrupted aortic arch: natural history and operative results.

The chances of survival for patients with interruption of the aortic arch depend mainly on early recognition and medical treatment before symptoms of cardiogenic shock appear, and specifically on early operative repair after the exact diagnosis has been established. Accurate angiography with visualization of the interrupted aortic arch and delineation of associated cardiac malformations is of prime importance for the surgical management and prognosis. Among our 36 patients with interrupted aortic arch, 27 were operated on. The operative mortality in 22 patients with associated ventricular septal defect (VSD) and persistent ductus arteriosus (PDA) was reduced from 43% (in seven patients seen up until 1979) to 7% (in 15 patients seen since 1980). One patient with interrupted aortic arch type C and another infant with associated truncus arteriosus were successfully corrected on day 9 and day 17 of life, respectively. In the patients with associated VSD and PDA as well as in the one patient with associated truncus arteriosus, the primary correction--direct anastomosis of the interrupted segments without prosthesis and VSD closure and in the case with truncus, the additional positioning of a valve-bearing allograft conduit from the right ventricle to the pulmonary artery--has been more successful than a two-step approach with initial pulmonary artery banding.

Aorta, Thoracic↗
PubMed1985

[Reconstruction of the right ventricular outflow tract with xenogeneic or allogeneic valve-bearing conduits].

From April 1974 to February 1985 131 patients were operated for reconstruction of the right ventricular outflow tract with 147 valve-carrying conduits. 79 were xenogenic (XC) and 68 sterilized and preserved allogenic (AC) conduits between right heart and lung in the following heart defects: DOLV 2, DORV 6, Fallot 24, pulmonary atresia 33, TGA, VSD and pulmonic stenosis 20, single ventricle 7, tricuspid atresia 10 and truncus arteriosus 41. Mean age was 6.6 and 5.2 years of age. The operative mortality was 13.6%. 11 more patients died later--2.0 months to 2.5 years postoperatively. 16 patients were reoperated (change of the conduit). The observation time is now 5 years in the XC-group and 1.4 years in the AC series. Up to now no dysfunction in the AC-group could be seen.

Adolescent↗
PubMed1985

Effect of hormones on transcription of the gene for cytosolic phosphoenolpyruvate carboxykinase (GTP) in rat kidney.

The effect of hormones on the transcription rate of cytosolic phosphoenolpyruvate carboxykinase and level of mRNA for this enzyme in the rat kidney has been investigated. In renal nuclei isolated from rats given dibutyryladenosine cyclic 3',5'-phosphate (Bt2cAMP) or 8-bromoadenosine cyclic 3',5'-phosphate (8-Br-cAMP), [32P]UMP incorporation into hybridizable phosphoenolpyruvate carboxykinase mRNA increased severalfold within 1 h. Changes in the concentration of cytosolic phosphoenolpyruvate carboxykinase mRNA, measured by hybridization of [32P]cDNA to poly(A)+ mRNA, paralleled alterations in the transcription rate. Dexamethasone treatment of adrenalectomized rats increased the transcription rate and the level of phosphoenolpyruvate carboxykinase mRNA 3-4-fold after 4 h. Both parameters then declined to control values by 8 h. When dexamethasone (5 mg/kg) and Bt2cAMP (25 mg/kg) were given together, the rate of phosphoenolpyruvate carboxykinase RNA synthesis and the level of cytosolic mRNA were not increased more than those with either drug alone. Transcription of the gene for renal phosphoenolpyruvate carboxykinase was not affected by diabetes or glucose refeeding but was increased 2-fold after 24 h of starvation and reduced by bicarbonate feeding after 2 h. We conclude that glucocorticoids and cAMP change the rate of transcription of the phosphoenolpyruvate carboxykinase gene in rat kidney, leading to changes of similar magnitude in mRNA level and, hence, enzyme activity. The results presented here and in previous work [Lamers, W., Hanson, R. W., & Meisner, H. (1982) Proc. Natl. Acad. Sci. U.S.A. 79, 5137] indicate that the transcription rate of the gene for phosphoenolpyruvate carboxykinase in liver and kidney responds to hormones in a tissue-specific manner.

Animals↗
PubMed1985

Ten years experience with povidone-iodine in heart surgery.

Ten years experience with povidone-iodine (PVP-I) (10%) ('Beta-isodona') in 7566 patients undergoing open-heart operations in the German Heart Centre, Munich, is reported. Povidone-iodine was used pre-, intra- and postoperatively for skin and wound disinfection according to a regime introduced more than 10 years ago and retained unchanged until today. The incidence of minor, superficial wound healing defects was 5%, whereas severe, deep sternal or retrosternal infections occurred in 0.5% of all patients. Superficial infections are no risk to the patient and can be treated successfully with local application of PVP-I. Deep infections, however, are associated with a mortality of about 40% despite the use of antibiotics and continuous wound irrigation with PVP-I (0.5%). Many factors contribute to the risk of these infections and only meticulous observation of aseptic and surgical technique, the prophylactic and therapeutic use of highly effective antibiotics, as well as the exclusion of sources of exogenous bacteria, can further reduce the incidence of these complications.

Anti-Bacterial Agents↗
PubMed1985

Open mitral commissurotomy. A new plea for an old operation.

From April 1974 through December 1982, 673 patients underwent surgery for isolated mitral valvular disease. Valve replacement was mandatory in 507 patients; of these, 255 received low-profile mechanical (mainly Björk-Shiley) prostheses and 252 bioprostheses. In 166 patients the mitral valve was amenable to reconstructive repair. This analysis is concerned exclusively with a subset of 127 patients, in whom open mitral commissurotomy was carried out (104 females and 23 males with a mean age at the time of operation of 45.5 years). There were 2 postoperative deaths, both due to intractable arrhythmias: one on the 4th postoperative day and one 6 years after surgery, giving a cardiac-related mortality of 1.5%. Thromboembolic complications were observed in 5 patients, none of whom developed permanent neurological deficits. There were 2 non-cardiac-related deaths: one of cancer and one of viral pneumonia. Mitral valve replacement was subsequently required in 2 patients at 2 and 7 years, respectively, after commissurotomy. Surgical intervention is pending for 2 further patients who appear likely to require valve replacement. Based on actuarial curves, the analysis of these results shows that, provided valvular morphology is suitable, open mitral commissurotomy is superior to valve replacement with respect to mortality rate and long-term survival.

Bioprosthesis↗
PubMed1985

Heart transplantation: limitations and perspectives.

The intrinsic limitations of heart transplantation are the restricted availability of donated organs, patient selection, hospitalisation costs, and the limited capacity of cardiac surgery clinics. With a better understanding of organ transplantation and heart transplants in particular, both by the general public and the medical profession, improvements in the care of patients with terminal myocardial disorders seem to be possible with heart transplantation. The one year survival rate for heart transplants is 80%. The success of the treatment is determined by the hemodynamic capacity of the transplanted organ, security against rejection reactions, effects of cellular transplant reactions, and side effects of immunosuppression. Within defined limits heart transplantation is the best standardised method of treatment for terminal myocardial failure.

Adolescent↗
PubMed1984

Tetralogy of Fallot. Development of hypoplastic pulmonary arteries after palliation.

Thirty-one patients with tetralogy of Fallot were studied angiographically before and after palliation with Blalock-Taussig operation (n = 9), Brock operation (n = 12), or enlargement of the right ventricular outflow tract with extracorporeal circulation (ECC) (n = 10). The relative diameter of the pulmonary vascular ring (PVR), pulmonary trunk (PT), and right and left pulmonary arteries (RPA, LPA) were measured before and 24.8 +/- 20.9 months after palliation. Using correlation analysis, the magnitude of growth of the pulmonary artery system was inversely related to its initial size. Mean pressure in the pulmonary artery after palliation as well as the period between date of surgery and recatheterization did not correlate significantly with growth. After Blalock-Taussig operation, the ipsilateral pulmonary artery predominantly increased in size without significant growth of PVR and PT. Brock operation and enlargement of the right ventricular outflow tract with ECC, improving the flow in the pulmonary vascular system centrally, induced a significant, symmetrical growth of the pulmonary vascular system and, therefore, are our methods of choice for palliation in patients with tetralogy of Fallow combined with hypoplastic pulmonary arteries.

Adolescent↗
PubMed1984

The treatment of tetralogy of Fallot: early repair or palliation?

Between 1974 and 1983, 380 consecutive patients with tetralogy of Fallot underwent surgery. In 73 patients, undergoing palliative surgery, the operative mortality and late mortality was 6.8%. Twenty-five of these patients have undergone subsequent complete repair, while 38 are awaiting correction. During the last 4 years we preferred operative procedures with enlargement of the right ventricular outflow tract (80%) to shunt operations (20%). In contrast to shunts, enlargement of the outflow tract induces a symmetrical growth of hypoplastic pulmonary arteries without the risk of acquired pulmonary atresia or peripheral stenosis at the site of anastomosis. Three hundred twenty-nine patients have undergone repair. In 101 patients, who had palliative operations before complete repair, the operative mortality was 12.9% and late mortality 2.9%. Those patients undergoing repair as a first operation had an operative mortality of 8.8%, and a late mortality of 1.3%. In the last 5 years the operative mortality for all patients, whether or not they had had previous palliative surgery, was 4.7%. The incidence of transannular outflow tract patching was not greater in children less than 2 years of age (16.9%) than in older children, 2 to 14 years of age (16.5%). However, in our experience the requirement for subvalvular outflow patches was higher in younger children (52.1%) than in the older children (34.1%). Because of this high incidence, particularly in younger patients, we have now begun to repair tetralogy of Fallot using the transatrial approach, thus reducing our use of subvalvular patches.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1984

[Isolated aortic isthmus stenosis: operation indications and results].

The goal of surgical correction of isolated coarctation of the aorta is normalization of the blood pressure. To assess the optimal age for the intervention with respect to operative morbidity and mortality, residual stenosis and recoarctation rate as well as the postoperative persistence of arterial hypertension without recoarctation, the pre- and postoperative findings of 237 patients (age at surgery: range one week to 17 years) were analyzed. The blood pressure, which was above the 95th percentile of age-matched normal values preoperatively in 93%, showed a clear decrease postoperatively in all age groups. On surgical correction, however, performed as of six years of age, there was a continuously increasing rate of persistent arterial hypertension without recoarctation which ranged from about 10% in those undergoing surgery between the ages of six and eight years to 31% in patients operated at ages between 13 and 17 years. In consideration of the operative results only with respect to the response of the resting blood pressure, insight is enabled only into one aspect of the prognosis, since the latter is equally dependent on the postoperative systemic arterial resistance. The systemic arterial resistance is already slightly elevated at three to five years of age, significantly increased as of six years of age, and at surgery after the age of six, shows a further increasing tendency. Accordingly, patients with postoperative normal or borderline-elevated blood pressure and apparently adequate surgical results, may be at risk of subsequent development of hypertension due to persistence of increased resistance, in particular, if surgery is performed after the age of five years.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗