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Biomedical subjects

R Grosse

Publications and source records attributed to R Grosse.

90 records · Page 5Linked to original sources
PubMed1977

Determination and functional significance of low affinity nucleotide sites of Ca2+ + Mg2+ -dependent ATPase of sarcoplasmic reticulum.

The protective effect of ATP, ADP and GTP against the inactivation of Ca2+ + Mg2+ -dependent ATPase by the thiol reagent NBD-chloride is used to calculate the apparent dissociation constants (K'D) of nucleotide enzyme complexes on the basis of a simple kinetic model. The K'D-values of the complexes with Mg-ATP (80 micrometer) and Mg-GTP (500 micrometer) are found to be rather close to their Km-values in the high concentration range supporting maximum activity. The requirement of the occupancy of the low affinity site by Mg ATP for a high rate of the Ca2+ transport system is explained in terms of the flip-flop mechanism established earlier for the analogous Na+ + K+-transporting ATPase system.

4-Chloro-7-nitrobenzofurazan↗
PubMed1976

[The functional coupling between MM isozyme of creatine phosphokinase (EC 2.7.3.2.) and MgATPase of myofibrils and (Na, K)ATPase of plasma membrane in heart cells].

The functional role of particulate MM isozyme of creatine phosphokinase (CPK) bound to heart myofibrils has been studied. It has been shown that in the presence of heart myofibrils and MgATP creatine phosphate can be used to rephosphorylate ADP formed in the MgATPase reaction. The rate of creatine phosphate splitting is determined by the kinetic properties of myofibrillar MgATPase and by the kinetic parameters of myofibrillar CPK. It has been found that a purified heart plasma membrane preparation contains high CPK activity. CPK isozyme bound to plasma membrane of heart cells is identical to MM isozyme of CPK and is able to rephosphorylate effectively ADP, formed in the (Na K)ATPase reaction. The rate of creatine phosphate splitting in these coupled reactions is sensitive to ouabain and is determined by the kinetic parameters both of the (Na, K)ATPase and plasma membrane CPK. The results obtained indicate the important role of myofibrillar and plasma membrane CPK in the intracellular energy transport processes.

Adenosine Triphosphatases↗
PubMed1975

Dermatoglyphic analysis as a diagnostic tool in Wilson disease?

Dermatoglyphic analysis was performed in a family with 3 children with Wilson disease. With our findings we could not confirm the results published in two earlier papers by other authors who noted a positive relation between Wilson disease and an increased number of whorls. The practical significance of the findings is discussed.

Dermatoglyphics↗
PubMed1975

On the influence of fructose-6-phosphate, ammonium, ATP and AMP on the conformation of the phosphofructokinase from rabbit muscle.

By means of circular dichroism measurements in the range from 210-240 nm and 250-300 nm it is shown that conformational changes of the phosphofructokinase from rabbit muscle correlate with the action of effectors on the enzyme. The postulated active and inactive states differ in the secondary structure. Addition of activators causes a conformational change which is interpreted as the transition of the inactive into the active state. At 210-240 nm no reversion could be observed but at 250-300 nm there are some indications for at least partial reversion.

Adenosine Triphosphate↗
PubMedDate not supplied

Characteristics of fatty acid-binding proteins and their relation to mammary-derived growth inhibitor.

Based on sequence relationships the cytoplasmic fatty acid-binding proteins (FABPs) of mammalian origin are divided into at least three distinct types, namely the hepatic-, intestinal- and cardiac-type. Highly conserved sequences of FABPs within the same type correlate with immunological crossreactivities. Isoforms of hepatic-type FABP are found in several mammalian species and for bovine liver FABP specific shifts in isoelectric points upon lipidation with fatty acids are observed. Isoforms of intestinal-type FABP are not known and the occurrence of cardiac-type isoforms so far is confined to bovine heart tissue. A bovine mammary-derived growth inhibitor (MDGI) is 95% homologous to the cardiac-type FABP from bovine heart. Dissociation constants of FABP/fatty acid complexes are in the range of 1 microM and 1:1 stoichiometries are usually found, but the neutral isoform of hepatic FABP from bovine liver binds 2 fatty acids. On subcellular levels hepatic- and cardiac-type FABPs are differently distributed. Though mainly cytosolic in either case, immunoelectron microscopy as well as a gelchromatographic immunofluorescence assay demonstrate the association of hepatic FABP in liver cells with microsomal and outer mitochondrial membranes and with nuclei, whereas in heart cells cardiac FABP is confined to mitochondrial matrix and nuclei. In mammary epithelial cells MDGI is associated with neither mitochondria nor endoplasmic reticulum, and is expressed in a strictly developmental-dependent spatial and temporal pattern. The specific role proposed for MDGI is to arrest growth of mammary epithelial cells when they become committed to differentiation in the mammary gland.

Amino Acid Sequence↗
PubMedDate not supplied

Hormonal induction of functional differentiation and mammary-derived growth inhibitor expression in cultured mouse mammary gland explants.

A method for the cultivation of organ explants from abdominal mammary glands of virgin mice has been established. In a serum-free medium containing aldosterone, prolactin, insulin, and cortisol (APIH medium) mammary gland development was documented by lobuloalveolar morphogenesis. The hormonal requirements for in vitro expression of beta-casein and of the mammary-derived growth inhibitor (MDGI) were tested. To this end, a full length cDNA coding for mouse MDGI was prepared displaying strong homologies to a mouse heart fatty acid binding protein, which is also expressed in the mammary gland. MDGI and beta-casein transcripts were found to be absent in the mammary tissue from primed virgin mice, and were induced upon culture of mammary explants in the APIH medium. An immunohistochemical analysis with specific antibodies against MDGI and casein revealed a different pattern of expression for the two proteins. In the APIH medium, MDGI was expressed mainly in differentiating alveolar cells of the lobuloalveolar structures, whereas beta-casein was present in both ductules and alveoli. The relationship between functional differentiation and MDGI expression was further studied in explants from glands of late-pregnant mice. At this stage of development, MDGI is found both in ducts and in alveoli. If explants were cultured with epidermal growth factor (EGF) and insulin, the lobuloalveolar structure was still present, whereas MDGI disappeared. Reinduction of MDGI expression was achieved by subsequent PIH treatment. Independent on developmental stage, EGF strongly inhibits MDGI mRNA expression. It is concluded that MDGI-expression is associated with functional differentiation in the normal gland.

Aldosterone↗
PubMedDate not supplied

Relationship between 43 kDa epidermal growth factor-related clonogenic activity and clinical parameters for breast cancer.

The clonogenic activity of a previously purified 43 kDa EGF-related protein (16) was estimated in the urine of breast cancer patients. Increase of activity was statistically significant in lymph node-positive patients, in a group of patients with larger carcinomas, with accelerated tumor growth, in premenopausal patients and younger age and in estrogen receptor negative patients. In 31 patients the activity was estimated during polychemotherapy before surgery. Differences between the values at the begin and the end of treatment were compared between all groups by the Kruskal-Wallis test (p = 0.02). Patients with progressive disease showed increasing activities (mean values from 315 to 811) while in those with complete remission activity decreased (from 449 to 213). Partial- and non responders showed no change. In a long-term follow-up study with 25 patients the pre- and postoperative activities were estimated. In 17 of 18 patients who had no local recurrence or metastasis the activity declined after surgery, whereas in 6 of 7 patients who died, activity increased 2-5 fold prior to death. A life table analysis with a total of 101 patients revealed a trend to shorter survival in the group with higher activity (p = 0.042). These observations suggest a role for the EGF-like growth factor activity in the expression of the malignant phenotype and may have significance for breast cancer diagnosis and prognosis.

Aged↗