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M Blum

Publications and source records attributed to M Blum.

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

Flow-cytometric determination of dehydrogenase activities in primary human gastrointestinal tumor cell lines.

The activities of 6 dehydrogenases, lactate dehydrogenase (LDH), glucose-6-phosphate dehydrogenase (G6PDH), isocitrate dehydrogenase (ICDH), glycerol-3-phosphate dehydrogenase (GDH), succinate dehydrogenase (SDH) and glutamate dehydrogenase (GLDH), determined by means of flow cytometry in 13 primary human gastrointestinal tumour cell lines, including 10 esophageal carcinomas, one gastric cancer, and 2 pancreatic cancers. Two-parametric measurements of specific dehydrogenase activities in single cells were performed with DAPI as fluorochrome for the nuclear DNA and with the fluorescent redox system of 5-cyano-2,3-ditolyl-tetrazolium chloride (CTC) which forms brilliant red formazan crystals upon reduction by cellular redox enzymes. Furthermore, with the aid of the calibration procedure reported previously [18] the enzyme activities were expressed as biochemical units. This application of tetrazolium salt technique for demonstrating dehydrogenase activities in human tumour cells by flow cytometry offers an alternative tool to characterize malignant tumors.

Adult↗
PubMed1993

Effect of sympathetic block demonstrated by triple-phase bone scan.

The triple-phase bone scan is frequently used in the diagnosis of reflex sympathetic dystrophy although the etiology of the abnormal findings is not well established. This study evaluated the effect of increased blood flow secondary to sympathetic block on the triple-phase bone scan. In 15 reflex sympathetic dystrophy patients, all of whom had significant relief with sympathetic block, baseline and postsympathetic block bone scans were analyzed. There was a significant linear relationship between change in counts from baseline to postsympathetic block on the blood pool image and bone uptake image. As the blood pool and bone uptake counts increased, the likelihood of typical reflex sympathetic dystrophy findings on visual inspection also increased. These results strongly support the concept of increased vascular flow as the cause of increased periarticular uptake.

Autonomic Nerve Block↗
PubMed1993

Characterization of porcine bone sialoprotein: primary structure and cellular expression.

Bone sialoprotein (BSP) is a highly glycosylated and sulphated phosphoprotein that is a major non-collagenous protein of bone. To further characterize the porcine protein and to study its expression during bone formation BSP cDNA clones were isolated from a porcine bone cDNA library. The primary sequence of the protein was derived from the nucleotide sequence of the largest cDNA insert and from the amino-terminal amino acid sequence determined by the automated Edman degradation procedure. When compared with sequences obtained from the human and rat BSPs 74% and 64% of the amino acids, respectively, were identical and a further 11% and 17%, respectively, were conservative replacements. Moreover, 60% of the amino acids in a concensus sequence derived from the primary sequences of mammalian BSPs were conserved with 16% conservative replacements. The two stretches of polyglutamic acid, through which the protein is capable of binding to hydroxyapatite, and an RGD motif that mediates cell attachment are retained in conserved sequences as are a number of potential sites of serine, threonine and tyrosine phosphorylation, glycosylation and tyrosine sulphation. Secondary structure prediction and hydrophilicity analysis indicate that the nascent BSP has an open flexible structure with the potential to form significant amounts of alpha-helix and some beta-sheet. In situ hybridization of fetal porcine bone with cRNA probes to porcine BSP mRNA shows that BSP is specifically expressed in differentiated osteoblasts on the surface of newly-forming bone trabeculae with especially high levels of hybridization at sites of de novo bone formation. The highly conserved features of BSP and its restricted distribution indicate an important role for this sialoprotein in the formation of bone.

Amino Acid Sequence↗
PubMed1993

Glucocorticoid receptor function in rat pituitary intermediate lobe is inhibited by an endogenous protein.

Though glucocorticoids inhibit proopiomelanocortin (POMC) gene expression and POMC-derived peptide release from corticotroph cells of the anterior pituitary, the regulation of this gene by glucocorticoids is less clear in the melanotroph cell of the pituitary intermediate lobe. To examine the difference between glucocorticoid sensitivity of the anterior lobe (AL) and intermediate lobe (IL) of the pituitary we have examined glucocorticoid receptor (GR) status of these two tissues and the role glucocorticoids play in regulating IL POMC gene expression. The rate of in vivo GR gene transcription, measured by nuclear run-on assay was consistently higher in the pituitary neurointermediate lobe (NIL) compared with the AL of the same animals. On a concentration basis, cytoplasmic GR mRNA in the NIL was similar to that found in the AL, and GR binding using [3H]dexamethasone (DEX) as ligand demonstrated similar concentrations of specific [3H]DEX binding in acutely isolated AL and NIL tissues. The specific Type II corticosteroid receptor ligand RU28362 displaced [3H]DEX binding to levels equivalent to non-specific binding, thus indicating that DEX was binding only to Type II corticosteroid receptors. To assess the direct action of glucocorticoids on POMC gene expression, NIL cells were cultured for 7 days and then treated with DEX. One hour DEX treatment of NIL primary cultures had no effect on levels of POMC heteronuclear RNA levels; in contrast, DEX induced a rapid and potent inhibition of POMC heteronuclear RNA levels in cells treated with the protein synthesis inhibitor puromycin.(ABSTRACT TRUNCATED AT 250 WORDS)

Androstanols↗
PubMed1993

Alignment of amino acid and DNA sequences of human proline-rich proteins.

Human proline-rich proteins (PRPs) constitute a complex family of salivary proteins that are encoded by a small number of genes. The primary gene product is cleaved by proteases, thereby giving rise to about 20 secreted proteins. To determine the genes for the secreted PRPs, therefore, it is necessary to obtain sequences of both the secreted proteins and the DNA encoding these proteins. We have sequenced most PRPs from one donor (D.K.) and aligned the protein sequences with available DNA sequences from unrelated individuals. Partial sequence data have now been obtained for an additional PRP from D.K. named II-1. This protein was purified from parotid saliva by gel filtration and ion-exchange chromatography. Peptides were obtained by cleavage with trypsin, clostripain, and N-bromosuccinimide, followed by column chromatography. The peptides were sequenced on a gas-phase protein sequenator. Overlapping peptide sequences were obtained for most of II-1 and aligned with translated DNA sequences. The best fit was obtained with clones containing sequences for the allele PRB4M (Lyons et al., 1988). However, there was not complete identity of the protein amino acid sequence and the DNA-derived sequences, indicating that II-1 is not encoded by PRB4M. Other PRPs isolated from D.K. also fail to conform to any DNA structure so far reported. This shows the need to obtain amino acid sequences and corresponding DNA sequences from the same person to assign genes for the PRPs and to determine the location of the postribosomal cleavage points in the primary translation product.

Amino Acid Sequence↗
PubMed1993

Ovine anterior pituitary proopiomelanocortin gene expression is not increased by ACTH secretagogues in vitro.

Recent reports have demonstrated that the secretion of ACTH from sheep anterior pituitary primary cultures is markedly stimulated by arginine vasopressin (AVP) but not by CRF, and that AVP-stimulated ACTH secretion is potentiated by CRF. It has also been reported that AVP increases total ACTH content (secreted plus intracellular ACTH), suggesting that AVP stimulates POMC biosynthesis in the ovine anterior pituitary. These observations differ from the rat, in which CRF is the most potent of the ACTH-releasing factors and the only ACTH secretagogue which stimulates POMC gene expression and biosynthesis. The second messenger pathways which mediate CRF- and AVP-stimulated ACTH release (protein kinase A and protein kinase C, respectively) are the same in sheep and rat corticotrophs. The present studies were undertaken to determine if ovine POMC gene expression, unlike the rat POMC gene, is stimulated by AVP via the protein kinase C pathway. A 295 base pair portion of the ovine POMC gene was isolated using polymerase chain reaction and sequenced. Ovine POMC messenger RNA (mRNA) levels were quantitated using this partial complementary DNA clone in a solution hybridization/nuclease protection assay with cytoplasmic RNA from sheep anterior pituitary primary cultures which had been treated with various combinations of ACTH secretagogues or with glucocorticoids for 18 h. Treatment with AVP, alone or with CRF, greatly increased total and secreted ACTH levels; however, the amount of POMC mRNA in these cells was not significantly increased. Treatments which stimulated secretion to a lesser extent and did not alter total ACTH levels (CRF alone, cAMP alone, or with phorbol ester) were associated with a decrease in POMC mRNA levels relative to untreated cells. Glucocorticoid treatment decreased both total ACTH and POMC mRNA levels. Taken together, the data demonstrate a lack of secretagogue-induced stimulation of POMC mRNA levels concomitant with increased total ACTH levels, an unexpected result given the close association between secretion of POMC-derived peptides and POMC gene expression in other mammalian corticotroph systems.

Adrenocorticotropic Hormone↗
PubMed1993

Expression of the mouse goosecoid gene during mid-embryogenesis may mark mesenchymal cell lineages in the developing head, limbs and body wall.

After an earlier, transient phase of expression in the developing primitive streak of 6.4- to 6.8-day mouse embryos, the homeobox gene goosecoid is now shown to be expressed in a later phase of mouse development, from 10.5 days onwards. The later, spatially restricted domains of goosecoid expression are detected in the head, limbs and ventrolateral body wall. At all sites, the domains of expression are first detected in undifferentiated tissue, and then expression persists as these tissues undergo subsequent morphogenesis. For example, goosecoid expression is noted in the first branchial arch at 10.5 days, and then expression persists as this tissue undergoes morphogenesis to form the lower jaw and the body of the tongue. Expression in tissues around the first branchial cleft persists as these undergo morphogenesis to form the base of the auditory meatus and eustachian tube. Expression in tissues around the newly formed nasal pits persists as these elongate to form the nasal chambers. Expression in the ventral epithelial lining of the otic vesicle persists as this eventually gives rise to the non-sensory epithelium of the cochlea. Expression in the proximal limb buds and ventrolateral body wall persists as these tissues undergo morphogenesis to form proximal limb structures and ventral ribs respectively. Our findings lead us to suggest that the goosecoid gene product plays a role in spatial programming within discrete embryonic fields, and possibly lineage compartments, during organogenesis stages of mouse development.

Abdominal Muscles↗
PubMed1993

32P-postlabelling studies on the DNA adducts of the food mutagens/carcinogens IQ and PhIP--adduct formation in a chemical system, and by rat and human metabolism.

The DNA adducts of the food mutagens/carcinogens IQ and PhIP were studied by means of 32P-postlabelling techniques. Adducts were generated in vitro and in vivo by three techniques: by photolysis of azido-IQ and azido-PhIP in the presence of dGp, calf-thymus DNA or Salmonella; by administration of IQ and PhIP to rats; and by incubation of cultured COS-1 cells with IQ. These cells expressed the human cytochromes P450 1A1 or P450 1A2 and/or the human N-acetyltransferases NAT1 or NAT2. The data demonstrate that, in the photolytic, rat and human systems, a common IQ metabolite and a common PhIP metabolite are formed together with common sets of IQ adducts and PhIP adducts. The data obtained in the human system show that N-hydroxy-IQ, formed by cytochrome P450, binds poorly to DNA, whereas more efficient binding occurs in the presence of NAT1 and most efficient binding in presence of NAT2. This indicates an O-acetyltransferase activity of human NAT1 and NAT2 and formation of N-acetoxy-IQ as an intermediate and immediate precursor of the ultimate arylnitrenium ion. The effect of the polymorphic NAT2 suggests a critical role for the human acetylation polymorphism in the DNA-binding of IQ in humans and in its genotoxic implications.

Animals↗
PubMed1993

[Traumatic cataracts. Surgical methods and results in 106 patients].

Eyes with traumatic cataracts comprise a very heterogeneous group with respect to morphological and functional changes in the anterior and posterior segments. In the current study, data on 106 eyes with traumatic cataracts were analyzed. All eyes had undergone surgery at the Department of Ophthalmology at the University of Heidelberg between 1987 and 1991. There was a total of 55 blunt (group A) and 51 perforating (group 2) injuries. The male-to-female ratio was 2:1; the mean age was 54.8 (+/- 15.2) years in group 1 and 43.7 (+/- 19.1) years in group 2. In 91.4% of the eyes in group A without zonular defects (A1, n = 35) and 65% with zonular defects (A2, n = 20) a posterior chamber IOL was implanted. This value was 66.7% following perforating injuries (B, n = 51). Mean visual acuity was 0.68 +/- 0.29 for group A1, 0.56 +/- 0.35 for group A2, and 0.52 +/- 0.30 for group B. In 7.5% of all eyes additional surgery was required because of delayed complications. Overall, relatively good visual acuity was obtained, but results largely depended on the severity of traumatic damage to the eye and the status of the zonular/capsular apparatus.

Adult↗
PubMed1993

Effect of verapamil on disposition of intravenous potassium in diabetic anephric uremic rats.

Calcium channel blockers decrease the plasma potassium concentration in acutely nephrectomized rats exposed to an acute potassium load. We examined the effect of verapamil on the plasma potassium concentration during an acute potassium load in anephric-uremic diabetic and non-diabetic rats. The plasma potassium concentration was measured at 15-min intervals during 60 min of continuous KCl infusion, with and without verapamil. The baseline potassium concentrations were higher in diabetic rats vs. nondiabetic controls. Verapamil blunted the increase in plasma potassium in diabetic and nondiabetic rats compared with the respective controls. The pH and hematocrit were similar in all groups. We conclude that the effect of verapamil on extrarenal potassium disposal are independent of insulin and the renin angiotensin system in the uremic state.

Animals↗
PubMed1992

Gastrulation in the mouse: the role of the homeobox gene goosecoid.

Mouse goosecoid is a homeobox gene expressed briefly during early gastrulation. Its mRNA accumulates as a patch on the side of the epiblast at the site where the primitive streak is first formed. goosecoid-expressing cells are then found at the anterior end of the developing primitive streak, and finally in the anteriormost mesoderm at the tip of the early mouse gastrula, a region that gives rise to the head process. Treatment of early mouse embryos with activin results in goosecoid mRNA accumulation in the entire epiblast, suggesting that a localized signal induces goosecoid expression during development. Transplantation experiments indicate that the tip of the murine early gastrula is the equivalent of the organizer of the amphibian gastrula.

Activins↗
PubMed1992

The possible relationship between menorrhagia and occult hypothyroidism in IUD-wearing women.

A high incidence of occult hypothyroidism in menorrhagic women has been reported and emphasized in recent studies. In order to verify this statement, we have evaluated the functional status of the thyroid gland in intrauterine device (IUD) wearers suffering from increased menstrual bleeding. The study group consisted of 40 IUD-wearing women, aged 26-46 years, suffering from metrorrhagia. The control group consisted of 38 IUD-fitted women, 22-44 years old, in whom menstrual bleeding was not significantly increased. Menorrhagia was defined as excessive vaginal bleeding lasting for 6 days or more, and/or containing a significant amount of blood clots. Free thyroxine (FT) and thyroid-stimulating hormone (TSH) levels were assessed. FT levels were identical in both groups and within the normal range (1.31 +/- 0.28 ng/dl). TSH levels were significantly higher in the study group than in the controls, although they remained within the normal range (2.75 +/- 2.06 vs. 1.45 +/- 0.45 microU/ml, p < 0.01). A thyrotropin-releasing hormone (TRH) test was performed in 10 women having the highest TSH levels. All the results of TRH tests were consistent with occult hypothyroidism. These women were treated with L-thyroxine and all had a significant improvement in their bleeding within 3 months of treatment. We concluded that any IUD-wearing woman suffering from menorrhagia may have occult hypothyroidism. Should FT and TSH be within normal limits, a TRH test should be performed as the definitive diagnostic test. A frequent side-effect of intrauterine contraception is menometrorrhagia. The intrauterine device (IUD) has to be removed in 5-15% of cases to prevent iron deficiency anemia.

Adult↗
PubMed1992

Transynaptic regulation of low-affinity p75 nerve growth factor receptor mRNA precedes and accompanies lesion-induced collateral neuronal sprouting.

The bilateral sympathetic innervation of the rat pineal gland from the two superior cervical ganglia (SCG) is a useful model system to investigate the mechanisms by which intact neurons compensate for neuronal losses. Cutting of the internal carotid nerve (ICN) on one side has been shown to result in the removal of approximately one-half of the innervation to the pineal gland within 2 days. This denervation is followed by the development of collateral neuronal sprouting from the contralateral "intact" SCG, most of which takes place during the next 2 days. Using a solution hybridization protection assay, levels of low-affinity NGF receptor p75NGFR mRNA (pg/microgram total RNA) were found to be increased 25%, with no change in cyclophilin mRNA, in the SCG contralateral to the lesion performed 1 or 3 days earlier. In situ hybridization with a 35S riboprobe complementary to p75NGFR mRNA demonstrated a large increase in this mRNA in some cells of this intact SCG at both 1 and 3 days after a contralateral ICN cut lesion. The clustering of these cells toward the rostral portion of the SCG suggests that they may overlap with the population of sympathetic neurons which provides innervation to bilaterally innervated structures such as the pineal gland. The nature of the signals involved in the regulation of NGF receptor mRNA levels and their role in initiating and maintaining collateral sprouting remain to be fully established. Nevertheless, the time course of the changes in mRNA levels suggests that regulation of the low-affinity NGF receptor gene may be involved in the sequence of events associated with the collateral sprouting response by intact sympathetic nerve cells following partial denervation.

Amino Acid Isomerases↗
PubMed1992

Genomic structure of the locus associated with an insertional mutation in line 4 transgenic mice.

In line 4 transgenic mice, six to eight copies of a 50-kb lambda recombinant clone are arranged in a head-to-tail tandem array on chromosome 3. Embryos homozygous for the transgene become arrested in their development on Day 5 of gestation shortly after implantation. The insertion site was cloned using a small segment of the transgene as a probe. Comparison of the insertion site with the wildtype locus indicates that a 22-kb deletion of host DNA has occurred in line 4 mice. Restriction enzyme analyses showed that neither the tandem array nor the flanking chromosomal DNA had any detectable rearrangements. Sequencing of the junctions between host and foreign DNA, however, revealed insertions of small fragments of DNA of unknown origin as well as an insertion of a DNA segment derived from another region of the transgene. Therefore, disruption of an essential gene in the line 4 transgenic mouse may have been caused by the insertion of 300-400 kb of foreign DNA or a deletion of sequences in the host genome.

Animals↗
PubMed1992

A Hox 3.3-lacZ transgene expressed in developing limbs.

We describe transgenic mouse lines that express lacZ under the control of the Hox 3.3 Promoter II. The correct anterior boundary can be fixed by 3.6 kb of promoter DNA (plus 1.6 kb of 5' transcribed sequences), both in tissues of ectodermal and mesodermal origin. The posterior border, however, is not respected, and lacZ expression continues into the tail region. One line has particularly strong graded expression in the anterior proximal limb bud. Other lines, containing a shorter promoter fragment (0.6 kb), have ectopic expression in the head region, including one line that has expression in the anterior half of the retina. Such mouse lines make it possible to molecularly distinguish cells in regions of the embryo that look otherwise identical and may be useful in studying the establishment of molecular differences in the mouse embryo.

Animals↗