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Biomedical subjects

M Meyer

Publications and source records attributed to M Meyer.

At least 361 records · Page 20Linked to original sources
PubMed1995

Treatment of acute renal failure with urodilatin after unrelated bone marrow transplantation in an 18-month-old boy.

Acute renal failure was imminent in an 18-month-old male infant 20 days after unrelated BMT. The infant was treated with urodilatin (URO), a natriuretic vasorelaxant peptide. Diuresis increased 2 h after the commencement of URO infusion and the furosemide infusion was reduced from 5 mg/h to 2.5 mg/h. After seven days of URO treatment diuresis was normal, the serum creatinine level had decreased, and furosemide was reduced from 12 mg/kg bw/d to 1.8 mg/kg bw/d. No side effects were observed either during or following URO therapy. We consider URO to be a promising drug for the treatment, without any apparent side effects, of imminent or manifest acute renal failure in infants following BMT.

Acute Kidney Injury↗
PubMed1995

Caring and the health professions.

This study analyzes patient descriptions of what constitutes caring in the physician and nurse. We propose that health care students can be taught caring behavior through the use of patient narratives.

Humans↗
PubMed1995

[Transverse fracture of the body of C2. Apropos of a case].

INTRODUCTION: A new fracture of the body of C2 is described. The mechanism is an axial compression producing a body sagittal fracture spreading to the posterior arch with a separation effect. CASE REPORT: A 29 years old female fell from the second floor. Examination showed a head injury and upper neck stiffness. Specific radiological signs was reported on the standard X-ray. The fracture involved the body and the lamina of C2 with a sagittal separation. No neurological abnormality was detected. CT scan provided additional information and allowed the survey of bone healing. Non operative treatment was undertaken by minerva jacket for four months carying complete recovery. DISCUSSION: The mechanism of this fracture seems to be similar to Jefferson's fracture. Review of the literature showed that fractures of the body of C2 are uncommon. Their different types are discussed.

Accidental Falls↗
PubMed1995

Synthesis, purification and biological activity of (Ser10-phosphatidyl)-urodilatin (phosphourodilatin).

Based on the global phosphorylation approach, a selective synthesis of (Ser10-phosphatidyl)-urodilatin (phosphourodilatin), which contains 32 amino acid residues and a disulfide loop is described. The peptide was assembled stepwise on a polyethyleneglycol-polystyrene support using Fmoc-chemistry. The phosphorylation was performed on-resin by phosphitylation with a large excess of di-tert-butyl-N,N-diethylphosphoramidite within 1 hour, followed by oxidation with tert-butylhydroperoxide to the protected phosphopeptide. After cleavage and deprotection the disulfide bridge was introduced without side reactions by iodine titration of the mono-acetamidomethyl protected crude peptide. During the synthetic pathway, the acylation with side chain-unprotected Fmoc-serine and the phosphitylation satisfactorily yielded the expected intermediates. In some phosphorylation experiments a by-product having a reduced mass corresponding to the H-phosphonate was observed. Illustrated with the synthesis of phosphourodilatin, this type of by-product, which could not be separated by HPLC, and the difficult amino acid sequence make the synthesis of a large phosphopeptide a more delicate task than the synthesis of short phosphopeptides, which do not contain oxidation-sensitive amino acids, difficult sequences or additional structural elements such as disulfide loops. The biological activity of phosphourodilatin was compared with non-phosphorylated urodilatin in two assay systems. Both peptides revealed a vasorelaxant effect on aortic smooth muscle strips and induced a cGMP-generation in RFL-6 cells with increasing dose dependency.

Acylation↗
PubMed1994

Activation of protein kinase C family members by the novel polyphosphoinositides PtdIns-3,4-P2 and PtdIns-3,4,5-P3.

The effect of phosphoinositides on the activity of protein kinase C (PKC) isotypes was investigated. PKC alpha, beta I, beta II, gamma, delta, epsilon, eta, and zeta were expressed in baculovirus-infected insect cells and purified by column chromatography. The calcium-activated PKC isotypes alpha, beta I, beta II, and gamma were not significantly activated by any of the phosphoinositides investigated (phosphatidylinositol-4-phosphate (PtdIns-4-P), PtdIns-3-P, PtdIns-4,5-P2, PtdIns-3,4-P2, and PtdIns-3,4,5-P3) when added in the presence of concentrations of phosphatidylserine that give maximal stimulation. The calcium-insensitive PKC isotypes delta, epsilon, and theta also showed little response to PtdIns-3-P, PtdIns-4-P, or PtdIns-4,5-P2 when these lipids were added in the presence of phosphatidylserine. In contrast, PtdIns-3,4-P2 and PtdIns-3,4,5-P3 caused a 5-15-fold stimulation of these enzymes compared with phosphatidylserine alone. 50% maximal stimulation of PKC epsilon by PtdIns-3,4,5-P3 occurred when this lipid was present at about 1% of the carrier PtdIns-4,5-P2 (about 100 nM). These lipids had little effect on baculovirus-expressed PKC zeta, which was constitutively active. A short chain version of PtdIns-3,4,5-P3, dioctanoyl-PtdIns-3,4,5-P3, activated PKC delta, epsilon, and eta in the absence of other lipids, whereas a short chain version of PtdIns-4,5-P2, dihexanoyl-PtdIns-4,5-P2, did not. Since PtdIns-3,4-P2 and PtdIns-3,4,5-P3 are nominally absent in unstimulated cells and appear within seconds to minutes of stimulation by various cell activators, these lipids could act as second messengers to activate PKC delta, epsilon, or eta in vivo.

Animals↗
PubMed1994

Characterization of cyclic nucleotide phosphodiesterase isoenzymes in the human ureter and their functional role in vitro.

An increase in cyclic nucleotide monophosphate levels is suggested to play a prominent role in mediating smooth-muscle relaxation. Cyclic nucleotide phosphodiesterase (PDE) influences smooth-muscle tone by decreasing the level of cyclic nucleotides. At present, five different families of isoenzymes of PDE exist that show a distinct species- and organ-specific distribution. Our study was done to evaluate the existence of specific PDE isoenzymes and its functional role in human ureteral tissue. Normal ureteral tissue was homogenized and centrifuged and the supernatant fraction was separated using anioin-exchange diethylaminoethyl (DEAE)-Sephacel chromatography. A PDE assay was then performed and the peak fractions were added to different specific PDE activators and inhibitors. In vitro, longitudinal ureteral strips were precontracted and different selective and non-selective PDE inhibitors were added incremently. Three different PDE isoenzymes were characterized: PDE I (calmodulin-sensitive), PDE II (cGMP-stimulated), and PDE IV (cAMP-specific). All PDE inhibitors relaxed the strips dose-dependently, with the 50% effective concentrations (EC50) being 30 microM for papaverine, 40 microM for zaprinast, 25 microM for quazinone, and 0.1 microM for rolipram. The ureter-relaxing effect of the PDE IV inhibitor at low concentrations, combined with its low-level effect on the systemic circulatory parameters, may open the possibility of using selective PDE IV-inhibitors in the treatment of ureteral colics or for ureteral stone passage.

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMed1994

Long-term changes in the magnetic resonance image after chemonucleolysis.

After treatment of a symptomatic herniated disc with chymopapain, 14 patients were re-examined by magnetic resonance imaging (MRI) at a mean follow-up of 72 months. Well-defined MRI findings before chemonucleolysis were compared with those after the procedure by an independent observer. Five MRI parameters were assessed. No significant change was noted in the signal intensity of the affected disc, the extent of osteochondrosis and endplate reaction of the affected segment. The height of the affected disc as well as the size of the disc herniation were reduced significantly. The loss of the height is seen as a direct result of chymopapain activity, whereas the alteration of the size of the herniation seems to depend on the natural history of a disc herniation and is probably not a simple result of the treatment.

Adult↗
PubMed1994

Prognostic evaluation of intracranial metastasis in malignant melanoma.

BACKGROUND: Malignant melanoma (MM) is often reported as the third most common cause of intracranial metastasis (IM) after carcinoma of the breast and lung. Most patients with advanced MM will have widespread extracranial disease, but the majority will die from intracerebral spread. METHODS: A retrospective review of 117 patients with documented IM from MM over the past 25 years was undertaken. Various factors (including age, race, sex distribution, primary lesions with Clark's level, Breslow's thickness, primary sites and staging at initial presentation, diagnosis of IM and its various treatment methods, survival data, and autopsy findings) were analyzed. Prognostic indicators were clarified from this analysis as a predictor of central nervous system (CNS) metastasis. An ideal treatment plan was also analyzed in order to predict a better survival. RESULTS: Fifty-eight percent of patients were male; 42% were female. Seventy-one percent of the primary lesions were of Clark's level IV and V, with mean Breslow's thickness of 3.5 mm. Median time interval between the initial diagnosis and development of IM was 3.5 years. Complete surgical resection of the intracranial lesion in the brain resulted in the longest mean survival of 10.3 months, whereas mean survival for the group with no treatment was only 3 weeks. Patients with primary lesions of the head and neck had the lowest mean survival of 3.3 months, whereas those whose primary sites were unknown had the longest mean survival of 7.5 months. One- and 2-year survival were 9% and 3%, respectively. All but one of the 30 patients at autopsy were found to have visceral metastasis, namely of the lung, liver, and bone. CONCLUSION: An aggressive search for metastasis should be undertaken in patients at high risk of developing CNS metastasis, e.g., male, head and neck primary, Clark's level IV and V, Breslow's thickness of > 3 mm, and presence of visceral metastases, mainly lung. A complete surgical resection should be attempted whenever possible, with adjunctive use of whole-brain irradiation, along with systemic chemotherapy for further control of recurrence and to prolong survival.

Adult↗
PubMed1994

Regulation of the transcription factors NF-kappa B and AP-1 by redox changes.

There is increasing evidence that reactive oxygen intermediates (ROIs) play an important role in cellular processes such as signal transduction and the control of gene expression. The activity of transcription factors like AP-1 and NF-kappa B is modulated by the redox state of the cell. NF-kappa B is activated by a prooxidant state in the cell and is therefore potentially inhibited by antioxidants. In contrast, AP-1 is strongly activated by antioxidants and shows reduced activity in the presence of oxidants. The antioxidant-mediated activation of AP-1 relies on the de novo synthesis of c-fos and c-jun mRNAs. Induction of c-fos expression is primarily mediated by transcription factors binding to the SRE element in the c-fos promoter. Thus SRE binding factors can be considered as primary antioxidant response factors, while AP-1 itself is a secondary response factor.

Antioxidants↗
PubMed1994

Prenylated isoflavanone from the roots of Erythrina sigmoidea.

A novel prenylated isoflavanone, sigmoidin I, has been isolated from the roots of Erythrina sigmoidea, in addition to the known isoflavones, corylin and neobavaisoflavone and the known pterocarpan, phaseollidin. Its structure was established as 7,4'-dihydroxy-3'-methoxy-5'-(3-methylbut-2-enyl) isoflavanone by means of spectroscopic analyses and chemical transformations. Neobavaisoflavone displayed antifungal potency in vitro with minimum inhibitory concentrations against Aspergillus fumigatus and Cryptococcus neoformans, of 50 mg ml-1.

Antifungal Agents↗
PubMed1994

Molecular and phenotypic mapping of the short arm of chromosome 5: sublocalization of the critical region for the cri-du-chat syndrome.

Forty-nine individuals have been identified with deletions or translocations involving the short arm of chromosome 5. While most display the classical phenotype of the cri-du-chat syndrome, several of the patients do not have the syndrome or have only a subset of the clinical features. Somatic cell hybrids containing the deleted chromosome 5 were derived from each patient. Each somatic cell hybrid was analyzed at the DNA level using 136 chromosome 5p-specific DNA fragments. It was possible to unambiguously order most of the chromosomal breakpoints present in the somatic cell hybrids based on the hybridization patterns of Southern blots. Further comparisons between the deletions present in the patients and their clinical features identified several chromosomal regions that were involved in specific clinical features. A critical chromosomal region involved the high-pitched cry mapped to 5p15.3, while the chromosomal region involved in the remaining features of the cri-du-chat syndrome mapped to a small region within 5p15.2. Deletions that did not include these two chromosomal regions presented varying clinical phenotypes from severe mental retardation and microcephaly to a clinically normal phenotype. These results demonstrate the need for careful characterization of a 5p deletion in prenatal cases before clinical predictions are made.

Animals↗
PubMed1994

Increased F-18 FDG accumulation in an acute fracture.

Markedly increased FDG uptake was noted in a 2-week-old fracture of the clavicle and scapula in a 24-year-old man. This finding emphasizes the need to consider benign etiologies such as trauma for focally increased FDG accumulation in bone.

Adult↗
PubMed1994

Urodilatin: a new approach for the treatment of therapy-resistant acute renal failure after liver transplantation.

A pilot study was performed in patients after liver transplantation (Ltx) to examine the effect of continuous intravenous urodilatin (URO, CDD/ANP-95-126)-infusion as an alternative therapy of acute renal failure (ARF) resistant to conventional therapy. Eight patients who developed ARF after liver transplantation and fulfilled requirements for haemodialysis/haemofiltration were treated. After URO infusion was started, renal function improved and all patients developed a strong diuresis and natriuresis within 2-4 h. The extracellular expansion due to sodium and water retention in anuric/oliguric ARF lead to an increased central venous pressure (CVP) and elevated blood pressure. During the URO infusion CVP declined and systolic, as well as diastolic, blood pressure were stable. In six patients where haemodialysis/haemofiltration could be avoided, serum creatinine (SC) and blood urea nitrogen (BUN) declined during URO treatment and creatinine clearance (CC) also improved significantly. Fluid and electrolyte disturbances changed promptly and normalized. This was in concordance with renal excretion of electrolytes. Two patients still required haemodialysis/haemofiltration. The six patients who did not require haemodialysis/haemofiltration after URO treatment normalized concerning their renal function and did well in a control period of 12 weeks. The study shows that continuous low dose URO infusion may present a new concept for treatment of postoperative acute renal failure resistant to conventional therapy.

Acute Kidney Injury↗