Search PubMed⌕ Search

Biomedical subjects

M Schulz

Publications and source records attributed to M Schulz.

At least 145 records · Page 8Linked to original sources
PubMed1994

Biosynthesis of carnosine and related peptides by skeletal muscle cells in primary culture.

Synthesis of carnosine (beta-alanyl-L-histidine) and related dipeptides could be demonstrated in primary muscle cell cultures derived from embryonic chick pectoral muscle. After incubation with radiolabeled beta-alanine or gamma-aminobutyric acid, the radiolabeled dipeptides were isolated from the cell extracts and also in small amounts from the culture medium. The kinetics of dipeptide formation indicated that anserine (beta-alanyl-1-methylhistidine) is not formed directly by these cells but as a secondary product via the methylation of carnosine. Coinciding with the morphological differentiation of the mononucleated myoblast to form multi-nucleated myotubes, a rapid increase in beta-alanine uptake and also in dipeptide synthesis could be observed. These results demonstrate that carnosine and related peptides are not merely deposited in skeletal muscles but that they are actively synthesized by muscle cells in culture.

Alanine↗
PubMed1994

[A compilation of therapeutic and toxic plasma drug concentrations].

In order to assess the significance of drug levels measured in clinical and forensic toxicology as well as for therapeutic drug monitoring (TDM), it is essential that good collections of data are readily available. For more than 400 frequently used drugs therapeutic and, if data were available, toxic and fatal plasma concentrations as well as elimination half-lives were compiled in a table including, e.g., hypnotics like barbiturates and benzodiazepines, neuroleptics, antidepressants, sedatives, analgesics, anti-inflammatory agents, antihistamines, anti-epileptics, beta-adrenergic antagonists, antibiotics (penicillins, cephalosporins, aminoglycosides, gyrase inhibitors), diuretics, calcium-channel blockers, cardiac glycosides, anti-arrhythmics, anti-asthmatics, angiotensin converting enzyme inhibitors, opioid agonists, and local anaesthetics. Data have been abstracted from published information, both compilations and primary sources, and supplemented with data collected in our own forensic and clinical toxicology laboratories. Wherever possible, ranges for therapeutic plasma concentrations are expressed as trough concentration at steady-state. The range of (or single) half-life values given for each drug are chosen to represent the terminal log-linear phase at most. In addition to the assessment of significance of drug levels for the therapeutic monitoring of patients, this list can assist the diagnostic assessment in cases of intoxication.

Drug Therapy↗
PubMed1994

Pharmacokinetics and effects on intracranial pressure of sufentanil in head trauma patients.

Ten patients with head trauma received an intravenous bolus of sufentanil (2 micrograms kg-1) followed at 30 min by infusion of sufentanil (median 150 micrograms h-1) and midazolam (median 9.0 mg h-1) over 48 h. Median (range) values of pharmacokinetic parameters for sufentanil were: t1/2,z = 16 (7-49) h; CL = 1215 (519-2550) ml min-1; CLR = 7 (2-38) ml min-1; Vss = 10.0 (6.8-24.2) 1 kg-1. Decreases in intracranial pressure (ICP) (from 16.1 +/- 1.7 to 10.8 +/- 1.3 mm Hg; P < 0.05) and mean arterial blood pressure (MAP) (from 85.5 +/- 3.9 to 80.2 +/- 4.9 mm Hg; P < 0.05) were observed within 15 min of the bolus injection of sufentanil and remained unchanged thereafter. Thus, cerebral perfusion pressure (CPP = MAP-ICP) was stable.

Adolescent↗
PubMed1994

Successful physostigmine treatment of acute dothiepin intoxication.

We report on a severe intoxication with the tricyclic antidepressant dothiepin. A treatment with a continuous infusion of physostigmine was successful and improved the ventricular arrhythmia. Dothiepin and its active metabolites were determined in plasma and urine by HPLC.

Adult↗
PubMed1993

Effect of proteoglycan purified from rat superior colliculus on the survival of murine retinal ganglion cells.

Recently, Schulz and coworkers purified a chondroitin sulfate proteoglycan from the superior colliculus of the neonatal rat which promoted survival of neonatal rat retinal ganglion cells in vitro. The present work tests whether this factor supports the survival of axotomised retinal ganglion cells in vivo. To this effect, murine retinae 15 and 20 days after conception were explanted to the chorioallantoic membrane of live chicken embryos. The explants, which were left in the egg for 1, 2 or 7 days, differentiated and grew according to a normal timetable. Purified proteoglycan from neonatal rat superior colliculus was applied daily to one group of retinae while a control group received Ham's F-10 medium. Results indicated that application of proteoglycan resulted in the preferential survival of large cells in the ganglion cell layer, namely ganglion cells, for up to 7 days post-explantation. In addition, the proteoglycan had a significant short-term anti-traumatic effect on the ganglion cell layer of explants by causing a 72% decrease in the number of dead cells relative to controls 1 day post-explantation. It was concluded that the chondroitin sulfate proteoglycan purified from the superior colliculus of the neonatal rat promotes the survival of fetal and neonatal murine retinal ganglion cells in retinae explanted to the chorioallantoic membrane of the chick.

Animals↗
PubMed1993

Purification of phosphoenolpyruvate carboxylase subunits and isoforms from Vicia faba L. by preparative gel electrophoresis and their detection by enzyme-linked immunosorbent assay.

A purification procedure which yields nearly homogenous subunits of stomatal phosphoenolpyruvate carboxylase from epidermal strips of Vicia faba L. is reported. Preparative gel electrophoresis was found to be the most suitable technique for subunit purification. Denatured subunits of the stomatal enzyme in the eluate were immunologically detected by enzyme-linked immunosorbent assay (ELISA) tests. The enzyme preparation meets all requirements for its use in antibody production.

Electrophoresis, Polyacrylamide Gel↗
PubMed1993

In vitro expression of osteoblastic markers in cells isolated from normal fetal and postnatal human bone and from bone of patients with osteogenesis imperfecta.

We studied the expression of osteoblastic markers in cultured cells isolated from the bone of 15 patients with different clinical forms of osteogenesis imperfecta (OI) and of seven fetal and postnatal controls. Cultured bone cells of ten OI patients produced abnormal collagen type I. Similar to controls, OI bone cells produced predominantly collagen type I with traces of collagen types III and V. The 1,25(OH)2 vitamin D3-stimulated synthesis of osteocalcin, a specific osteoblastic marker protein, was similar in OI bone cells and age-matched controls. Bone cells from fetal controls and from patients with the perinatal lethal OI type II produced less osteocalcin than bone cells from postnatal controls and surviving OI patients. OI bone cells responded to parathyroid hormone (PTH) by increased production of cAMP similar to controls. Bone cells from fetal controls and from OI type II donors showed a decreased response to PTH. Activity of the bone-liver-kidney isoenzyme alkaline phosphatase (AP) was detected in all control and OI bone cells. The expression of all osteoblastic markers was similar in bone cells producing abnormal collagen type I. These observations show that OI bone cells in vitro express a pattern of osteoblastic markers similar to age-matched control bone cells indicating that osteoblastic differentiation is not altered by the underlying defects of collagen type I metabolism in OI bone cells.

Alkaline Phosphatase↗
PubMed1993

Low dose alpha interferon treatment in chronic hepatitis B virus infection.

Fifty eight patients with chronic viral hepatitis B (HBV) were randomised in a prospectively controlled trial. Thirty patients were treated with 3 million units (MU) of interferon alfa-2b subcutaneously thrice weekly for four months. Twenty eight controls received no treatment. The follow up period after treatment was six months. Twenty eight treated patients and 27 controls completed the protocol. One woman in the treatment group showed a complete response, and eight other treated patients (32%) showed a partial response. Three patients in the control group (11%) lost hepatitis B e antigen and HBV-DNA spontaneously. This finding is statistically significant (p < 0.05). The elimination of HBV markers from the serum was associated with a return to normal of serum aminotransferase activities. Reactivation of hepatitis was not observed after seroconversion.

Adolescent↗
PubMed1993

[In vitro contractility of the musculature of human gallbladders with and without gallstones--relevance of the prostaglandin system for CCK regulated motoricity].

This study describes the influence of endogenous and exogenous prostaglandins upon CCK-induced motility patterns of human gallbladders with and without stones (indomethacin and nocloprost; an exogenous PGE2-analogon). From 48 gallbladders with- and 22 gallbladders without stones (control group) longitudinal muscle stripes were dissected and transferred to an organ bath and CCK, indomethacin and nocloprost dose response curves were established. In another experimental protocol, the effect of CCK after indomethacin or nocloprost preincubation is demonstrated. Moreover, specimens of gallbladders were taken for histology and gallstones for analyse. The results demonstrate that gallbladders with stones have a significant higher basic tonus and phasic activities compared to the stone-free controls. Because of these different responses to CCK, gallbladders of the stone-diseased group were divided in two groups: 64% of the gallbladders show a sensitivity and tonic response to CCK like the controls (contractors), 36% demonstrate a reduced sensitivity to CCK and only a slight tonic response (non-contractors). Indomethacin causes a fall in tonus in both stone-diseased groups. It stops spontaneous activity in the contractor and non-contractor group. With indomethacin preincubation all three groups response to CCK with a significant reduced sensitivity. CCK-induced activity is reduced in the control and contractor group. In the non-contractor group, muscle strips do not contract after indomethacin preincubation. Nocloprost induces significant contractions in the control and contractor group. In both groups, the response to CCK after nocloprost preincubation is stronger than the reaction without preincubation. In the non-contractor group, a change in tonus after nocloprost application cannot be demonstrated, there also is no response to CCK after nocloprost preincubation. These results corroborate the notion of a significant contribution of the endogenous prostaglandin system to the regulation of gallbladder motility by CCK.

Adult↗
PubMed1992

Partial purification and properties of an inducible uridine 5'-diphosphate-glucose-salicylic Acid glucosyltransferase from oat roots.

A salicylic acid (SA)-inducible uridine 5'-diphosphate (UDP)-glucose:SA 3-O-glucosyltransferase was extracted from oat (Avena sativa L. cv Dal) roots. Reverse phase high-performance liquid chromatography or anion exchange chromatography was used to separate SA from the product, beta-O-d-glucosylsalicylic acid. The soluble enzyme was purified 176-fold with 5% recovery using a combination of pH fractionation, anion exchange, gel filtration, and chromatofocusing chromatography. The partially purified protein had a native molecular weight of about 50,000, an apparent isoelectric point at pH 5.0, and maximum activity at pH 5.5. The enzyme had a K(m) of 0.28 mm for UDP-glucose and was highly specific for this sugar donor. More than 20 hydroxybenzoic and hydroxycinnamic acid derivatives were assayed as potential glucose acceptors. UDP-glucose:SA 3-O-glucosyltransferase activity was highly specific toward SA (K(m) = 0.16 mm). The enzyme was inhibited by UDP and uridine 5'-triphosphate but not by up to 7.5 mm uridine 5'-monophosphate.

Journal Article↗