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Biomedical subjects

M Marcinkiewicz

Publications and source records attributed to M Marcinkiewicz.

At least 19 recordsLinked to original sources
PubMed1992

Adenosine deaminase activity in the human duodenal mucosa in relation to gastric acid secretion.

Adenosine deaminase (ADA) activity was estimated in mucosal specimens obtained endoscopically from the duodenal bulb. Three groups of subjects were studied: 1. 9 patients with achlorhydria, 2. 12 subjects with normal gastric acid secretion, 3. 5 patients with hypersecretion. Enzyme activity was measured by determination of ammonia liberated from the substrate according to the Chaney and Marbach method. In patients with hypersecretion the ADA activity was lower than in those with achlorhydria (p less than 0.001) and normal acid secretion (p less than 0.02). A significant negative correlation between ADA activity in the duodenal bulb mucosa and basal and maximal gastric acid outputs was found. The present study seems to indicate a possible relationship between gastric acid secretion and duodenal ADA activity.

Achlorhydria↗
PubMed1991

Adenosine deaminase activity in the gastric mucosa in patients with gastric ulcer. Effects of ranitidine and sucralfate.

Adenosine deaminase activity was studied in the gastric mucosa of patients with peptic ulcer in relation to ulcer localisation and treatment with ranitidine or sucralfate. Enzyme activities observed in the corpus mucosa were higher at a distance of over 2 cm from the ulcer margin than that recorded close to the ulcer. A significant decrease in adenosine deaminase activity was found after treatment with ranitidine but not with sucralfate. In the antral mucosa, enzyme activity was constant in all the groups observed. The evaluation of adenosine deaminase activity in gastric mucosa can be useful for studies of pathologic changes in the stomach.

Adenosine Deaminase↗
PubMed1991

Evidence for atrial natriuretic peptide (ANP) synthesis and the presence of ANP-transducing receptors in the rat olfactory bulb.

This study demonstrates the presence of both atrial natriuretic peptide (ANP) precursor and ANP transcripts in the rat olfactory bulb (OB), a key brain structure involved in the generation of olfaction-dependent behavior. In addition to synthesizing ANP, the OB contains ANP-transducing receptors coupled to the guanylate cyclase system but it is devoid of ANP "clearance receptors." The characterization of biologically active ANP receptors and the evidence for in situ ANP synthesis in this region of the CNS adds credence to the hypothesis that the peptide plays a putative role in olfaction.

Animals↗
PubMed1991

Mammalian neural and endocrine pro-protein and pro-hormone convertases belonging to the subtilisin family of serine proteinases.

Conversion of pro-hormones and precursor proteins into biologically active peptides and proteins involves the concerted action of a number of convertases and post-translation modification enzymes. The identification of the yeast convertase kexin as a prototype processing enzyme led to the discovery of the mammalian convertase designated furin, PC1 and PC2. Whereas furin is ubiquitously expressed, PC1 and PC2 are found only in endocrine and neural tissues and cell lines. In man and mouse, the genes coding for furin, PC1 and PC2 reside on three different chromosomes. The analysis of the intracellular processing of PC1 and PC2 and the removal of their pro-segment is presented, together with a summary of the cleavage specificity of these enzymes for precursors such as pro-opiomelanocortin (POMC) and human pro-renin. The distinct tissue distribution of PC1 and PC2 and their coregulation with POMC in the pituitary neurointermediate lobe adds credence to their physiological role as convertases involved in the tissue-specific processing of precursor proteins.

Amino Acid Sequence↗
PubMed1991

Cloning and primary sequence of a mouse candidate prohormone convertase PC1 homologous to PC2, Furin, and Kex2: distinct chromosomal localization and messenger RNA distribution in brain and pituitary compared to PC2.

Using a 796-basepair cDNA fragment obtained from a mouse pituitary library we have screened two mouse insulinoma libraries and isolated a full-length cDNA clone (2516 basepairs; 753 amino acids), designated mPC1. The cDNA sequence of mPC1 codes for a protein containing 753 amino acids and three potential N-glycosylation sites. This cDNA encodes a putative novel subtilisin-like proteinase, exhibiting within its presumed catalytic domain 64%, 55%, and 47% amino acid sequence identity to the recently characterized candidate prohormone convertases human Furin, mouse PC2, and yeast Kex2 gene products, respectively. An identical sequence to mPC1 was derived from a cDNA library of mouse corticotroph AtT-20 tumor cells. An ArgGlyAsp tripeptide identical to the recognition sequence of integrins was observed in the structures of the mammalian PC1, PC2, and Furin. In situ hybridization results demonstrated a distinct localization of the mPC1 and mPC2 transcripts in pituitary and brain. Thus, whereas both mPC1 and mPC2 are found in the intermediate lobe of the pituitary, only mPC1 is easily detected in the anterior lobe. In extrahypothalamic regions of the brain, including cortex, hippocampus, thalamus, and spinal cord, mPC2 transcripts predominate over mPC1. Both mRNAs are found in only a fraction of hypothalamic neurons, with greater abundance of mPC1 over mPC2 in the supraoptic nucleus. The genes coding for mPC1 and mPC2 map to the murine chromosomes 13 (band 13c) and 2 (2F3-2H2 region), respectively.

Amino Acid Sequence↗
PubMed1989

CNS connections with the median raphe nucleus: retrograde tracing with WGA-apoHRP-Gold complex in the rat.

In this work we examined the neuronal input to one of the serotoninergic centers in the brain, median raphe nucleus (MR). Special consideration is given to projections of the hypothalamus. To describe the afferents to MR, a retrograde transport technique was used after microinjection of WGA-apoHRP-Gold complex under pressure and subsequent gold-silver intensification on formaldehyde-fixed rat brain sections. Optimal conditions were obtained when the coordinates of the injection site were A +/- 1.5, L +/- 0.15, and H +/- 2.7 according to Paxinos and Watson (The Rat Brain in Stereotaxic Coordinates. New York: Academic Press, '82). Results obtained under these conditions show a heterogeneous distribution of labeled neurons throughout the brain, including a large proportion (+/- 65%) of hypothalamic neurons. Extra-hypothalamic neurons projecting to MR were from the prefrontal cortex, lateral and medial habenular nuclei, the pontine area of the central grey, interpeduncular nucleus, dorsal raphe nucleus, oculomotor and trochlear nuclei, dorsal and laterodorsal tegmental nuclei, parabrachial nuclei, and lateral and interpositus cerebellar nuclei. Hypothalamic neurons connected to MR were found to be from medial and lateral preoptic areas, lateral hypothalamus, dorsomedian nucleus, the perifornical area, and the complex of mammillary bodies. Many other discrete regions contained different densities of labeled perikarya: the medial preoptic nucleus, paraventricular nucleus, retrochiasmatic area, arcuate nucleus, lateral magnocellular nucleus, and the posterior area. The MR appears as an integrative center receiving many neuroanatomically and functionally heterogeneous inputs from the whole brain.

Animals↗
PubMed1989

Does the olfactory system mediate water- and mineral-regulating mechanisms? Evidence of immunoreactive atrial natriuretic factor within olfactory mucosa.

The immunoreactivity of atrial natriuretic factor (ANF) was studied in the rat olfactory mucosa (OM). Endogenous immunoreactive ANF (IR-ANF) was purified from OM using Vycor glass beads for extraction and reverse-phase HPLC: two of three IR-ANF peaks, identified by retention time, were identical to both the circulating form of ANF (Ser99-Tyr126) and the ANF pro-hormone (Asn1-Tyr126). A radioreceptor assay, employing rat renal glomerular membranes, revealed that endogenous IR-ANF competed with radiolabelled ANF. IR-ANF was localized by immunocytochemistry in secretory cells of Bowman's gland and in some cells of the epithelial layer. The relatively low concentration of IR-ANF in the OM (2.5 ng/mg protein) suggests a local role of ANF in this tissue. This hypothesis is supported by the presence in OM of ANF-binding sites, characterized by a KD of 95 pM and a Bmax of 130 fmol/mg protein. We propose that ANF could be released from the OM and act throughout in a paracrine (if not autocrine) manner on some yet-unidentified targets containing ANF-binding sites.

Animals↗
PubMed1988

Two-dimensional immunoblotting analysis and immunocytochemical localization of the secretory polypeptide 7B2 in adrenal medulla.

The soluble proteins of bovine chromaffin granules were subjected to 2D-electrophoresis followed by immunoblotting with an antiserum against the pituitary peptide 7B2. One immunoreactive spot was visualized at a position corresponding to a molecular weight of 24,000 and to a pI of 5.2. Using peroxidase-antiperoxidase (PAP) pre-embedding immunocytochemical technique for electron microscopy, 7B2 has been localized within secretory granules with diameters of approximately 115 and 190 nm in noradrenergic and adrenergic cells respectively. These data establish that in chromaffin granules 7B2 represents a minor component of the acidic proteins which include the chromogranins A and B, secretogranin II and the enkephalin-containing peptides.

Adrenal Medulla↗
PubMed1988

Ultrastructural localization of secretory granule constituent chromogranin and 7 B 2.

Our immunoelectron microscopic pre-embedding method confirmed that chromogranin A (CGA) 7 B 2 and EGC were actual secretory granule constituents. The presence of these constituents in rough endoplasmic reticulum indicated their production in the tumor cells. Similar localization of CGA to 7 B 2 suggested that CGA may be secreted into the circulation as it is for 7 B 2. Different mechanism of granular formation is proposed between GH secreting adenomas and FSH secreting adenomas.

Adenoma↗
PubMed1988

Identification and localization of 7B2 protein in human, porcine, and rat thyroid gland and in human medullary carcinoma.

The novel, highly conserved polypeptide 7B2, which belongs to a new protein superfamily, was isolated from human and porcine hypophysis. The availability of a specific antibody to a synthetic fragment enabled 7B2 localization in a number of neurocrine and endocrine tissues and revealed its secretory character. 7B2 was purified from thyroid homogenates by HPLC chromatography and characterized by gel permeation chromatography (dimeric mol wt, approximately 40,000) and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (monomeric mol wt, 20,750). By immunocytochemistry 7B2 was colocalized with calcitonin in parafollicular cells and identified within secretory granules by electron microscopy. Three of nineteen human medullary carcinoma cases showed immunoreactive 7B2 within the early and late hyperplasia stages and neoplasia. Results suggest that 7B2 may play a role in endocrine function, possibly as a secretory substance, and may be a histochemical marker in addition to calcitonin for medullary carcinoma.

Animals↗
PubMed1988

Secretory protein 7B2 is associated with pancreatic hormones within normal islets and some experimentally induced tumors.

7B2 is a novel neuroendocrine polypeptide which belongs to an entirely new superfamily of proteins. In extension of previous reports on 7B2, these studies concern its expression in endocrine pancreatic tissue. They have been performed using specific antibodies prepared against two distinct synthetic fragments of 7B2 comprising amino acids 23-39 and 117-128 of the native human molecule isolated from pituitary gland. Pancreatic insulin-secreting tumors produced in transgenic mice contain high amounts of 21,500- to 22,000-dalton forms of 7B2. Using light microscopy (immunocytochemical colocalization with different pancreatic hormones), immunoreactivity to 7B2 (IR-7B2) was consistently found within cells producing insulin and glucagon and less consistently within pancreatic polypeptide-containing cells. As in previous reports concerning the brain, adenohypophysis, and thyroid gland, IR-7B2 could be detected by electron microscopy within secretory granules of alpha- and beta-like cells in islets. Furthermore, the IR-7B2 level was higher in extracts of insulin-producing tumors of the transgenic mice that contained the hybrid insulin II gene. In addition, IR-7B2 could be detected immunocytochemically in three of seven tumors produced in the rat by streptozotocin-nicotinamide treatment.

Adenoma↗
PubMed1988

[Decrease in the immunoreactivity of protein 7B2 in vasopressinergic cells in the supraoptic nucleus and in fibers of the neurohypophysis, in Brattleboro rats].

Immunoreactivity to the secretory protein 7B2 (IR-7B2) colocalizes with both AVP and Om in separate groups of neurons in the supraoptic nucleus. In mutant Brattleboro rats, which have aberrant AVP, which results in diabetes insipidus, 7B2 appears to be markedly decreased in vasopressinergic neurons and absent in their corresponding neurohypophyseal terminals. In contrast, no dramatic differences could be observed in oxytonergic somatas and fibers.

Animals↗
PubMed1987

Chromogranin B (secretogranin I), a putative precursor of two novel pituitary peptides through processing at paired basic residues.

During the course of reversed-phase high-pressure liquid chromatography (RP-HPLC) purification of the 7B2 peptide originally isolated in our laboratory from human pituitary gland extracts, two novel peptides were identified and purified to homogeneity. The complete amino acid sequence of the first one was established in 1985 and recently found to be entirely homologous to positions 420-493 of the just published chromogranin B sequence. This peptide, denoted GAWK, could originate from chromogranin B following specific cleavage at the basic amino acids flanking both termini of GAWK. Moreover, another peptide isolated in our laboratory from the same source and denoted CCB has been discovered and its sequence is also part of the same chromogranin B molecule. Here again, this peptide, occupying positions 597-653 and located at the COOH-terminal region of chromogranin B, could derive from specific processing at basic amino acids, Arg-Lys-Lys, present at positions 594-596. In a manner reminiscent of the relationship between pancreastatin and chromogranin A, it is proposed that both GAWK and CCB are produced from chromogranin B after specific processing at basic amino acids. These data are thus in favor of a putative role of chromogranins as precursors to potentially bioactive peptides.

Amino Acid Sequence↗
PubMed1987

Human pituitary tryptase: molecular forms, NH2-terminal sequence, immunocytochemical localization, and specificity with prohormone and fluorogenic substrates.

A human pituitary-derived serine protease, immunologically identical to human lung tryptase (Smith, T. J., Hougland, M.W., and Johnson, D.A. (1984) J. Biol. Chem. 259, 11046-11051), was found immunohistochemically to be associated with mast cells present in pituitary connective tissue. Western blotting combined with sodium dodecyl sulfate-polyacrylamide gel electrophoresis indicated the presence of multiple forms: a major Mr 36,300 form and three minor forms with Mr 32,400, 33,400, and 34,600. Two major forms with Mr 35,600 and 34,100 were detected by affinity labeling with 125I-D-Tyr-Glu-Phe-Lys-Arg-CH2Cl. Treatment of the pituitary tryptase preparation with N-glycosidase F indicated that some of the molecular weight heterogeneity results from N-linked glycosylation. The multiple molecular weight forms appear to have the same NH2-terminal sequence: Ile-Val-Gly-Gly-Gln-Glu-Ala-Pro. Pituitary tryptase has an apparent Mr = 110,000 by gel filtration on Sephadex G-200 in the presence of 0.3 M NaCl, indicating that the enzyme may be a tetramer of Mr = 32,400-36,300 subunits. However, this quaternary structure was not stable to gradient polyacrylamide gel electrophoresis. Human pituitary tryptase was so reactive toward synthetic tripeptide coumarin-containing substrates containing a pair of basic amino acids at the site of cleavage such as benzyloxylcarbonyl-L-Ala-L-Lys-L-Arg-4-methylcoumarin-7-amide (k cat/Km = 2.38 X 10(8) M-1 s-1) that Briggs-Haldane kinetics may apply. The reversible inhibitor NaCl at a concentration of 1 M decreased the k cat/Km for benzyloxylcarbonyl-L-Ala-L-Lys-L-Arg-4-methylcoumarin-7-amide to 6.53 X 10(6) M-1 s-1, which reflected a 100-fold increase in apparent Km. Based on active site titration with fluorescein mono-p-guanidinobenzoate hydrochloride, NaCl had no effect on the number of accessible active sites. Substrate specificity studies with prohormones indicated that pituitary tryptase has a preference for cleaving COOH-terminal to arginine or lysine residues which are preceded by a proline residue 4 or 6 residues NH2-terminal to the site of cleavage.

Amino Acid Sequence↗
PubMed1987

The pituitary polypeptide "7B2" is associated with LH/FSH and TSH cells and is localized within secretory vesicles.

A highly conserved polypeptide termed "7B2", isolated from human and porcine pituitaries, has been reported by immunoreactivity to be distributed in various organs. However, the highest concentration has been found in the pituitary as demonstrated by a specific radioimmunoassay. In order to determine the type of cells within the pituitary that contain 7B2 and to analyse its intracellular localization, specific immunocytochemistry techniques (unlabeled antibody, peroxidase-antiperoxidase) were used both for light and electron microscopy. Immunocytochemistry of both explants and monolayer-cell cultures of the adenohypophysis was studied. Immunoreactivity to 7B2 has been found in 21.9% of the total number of cells. After simultaneous staining of serial sections with appropriate antibodies, 7B2 was found to be colocalized with beta-LH/beta-FSH in gonadotrophs and with beta-TSH in thyrotrophs. In situ immunocytochemistry at the electron-microscopic level showed that immunoreactive 7B2 is compartmentalized within secretory granules. The small (130 to 250 nm) but not the large granules (400 to 700 nm) were labeled in gonadotroph-like cells and small granules (90 to 150 nm) were also labeled in thyroph-like cells. Study of the gonadotrophs in cell culture after Zamboni's fixation revealed weak to moderate immunoreaction in rough endoplasmic reticulum. The current findings as well as previous data indicate that 7B2 is synthesized, stored and possibly released from the adenohypophysis similarly to many other secretory products.

Animals↗
PubMed1987

Immunocytochemical localization of a novel pituitary polypeptide "7B2" in the gastro-intestinal tract of the rat.

Immunoreactivity to the polypeptide designated "7B2" recently isolated from human and porcine pituitary glands, appears to be consistently confined to neuroendocrine and endocrine cells in various tissues. In rat gut, immunoreactive 7B2 was found in endocrine-paracrine cells. Highly labeled cells were found in the antrum of the stomach and, cells with lower concentrations, in the fundus, duodenum, jejunum and ileum. Except for a few cells which were simultaneously positive for 5-hydroxytryptamine, and a few others showing Grimelius's reaction, "7B2" cells do not exhibit argentaffin and/or argyrophil character. The 7B2 polypeptide seems to be distributed amongst several different types of endocrine cells in the gut.

Animals↗
PubMed1986

CNS distribution of a novel pituitary protein '7B2': localization in secretory and synaptic vesicles.

A detailed study of the immunoreactivity distribution of a novel pituitary protein, '7B2', within specific brain regions and in spinal cord revealed a complex network of neurons and fibers. Immunoreactive cell bodies were found exclusively in the hypothalamus. Stained fibers were more widely distributed and encompassed nearly 100 structures, including several limbic and autonomic nuclei. Biogenic amine centers such as substantia nigra, raphe nuclei and locus coeruleus have also contained immunoreactive 7B2. Subcellular fractionation using differential centrifugation and Percoll gradient revealed the preferential localization of this protein within granule-enriched fractions of rat neurointermediate lobe of the hypophysis. In agreement, ultrastructural studies revealed the presence of 7B2 within secretory-like granules in the median eminence and within synaptic vesicles of selected extrahypothalamic nuclei. Based upon migration on SDS-PAGE, the apparent molecular weight of the major form of 7B2 extracted from different brain regions was found to be 22,000, identical to that of the pituitary form.

Animals↗