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Biomedical subjects

D Hock

Publications and source records attributed to D Hock.

At least 19 recordsLinked to original sources
PubMed1997

Isolation and characterization of the bioactive circulating human parathyroid hormone, hPTH-1-37.

The occurrence of hPTH-1-37 as the native bioactive circulating form of PTH-1-84 has now been obtained using a specific purification procedure for circulating parathyroid hormone, which involves a newly developed immunoenzymetric assay for N-terminally intact hPTH. In combination with two different methods of mass spectrometry, the molecular weight of the isolated immunoreactive peptide was shown to be 4401 Da, which corresponds to hPTH-1-37. Synthetic hPTH-1-37 material was tested in the chick bioassay and produced a clearcut increase in serum calcium concentration. We conclude that hPTH-1-37 is the native bioactive fragment of hPTH-1-84 in circulation.

Animals↗
PubMed1996

Secretion of a urodilatin-like immunoreactive (URO-like-IR) substance from a human kidney cell line (HEK-293).

The aim of this study was to explore whether sodium chloride is involved in the release of urodilatin from epithelial human embryonic kidney cells (HEK-293). Using a highly specific urodilatin radioimmunoassay combined with HPLC, gel chromatography, and a cyclic GMP generating bioassay, we demonstrate that HEK-293 cells release a biologically active 3.5 kD, urodilatin-like immunoreactive substance. To show the effect of sodium on urodilatin release, HEK-293 cells were incubated with cell culture buffer containing 120, 130, 140, and 150 mmol/l sodium, respectively. Urodilatin secretion from HEK-293 cells is increased to 176% when extracellular sodium is raised to 150 mmol/l (control: 120 mmol/l = 100%). There was no significant difference when exposing the cells to 140 mmol/l or 150 mmol/l sodium. It is suggested, that beside the known extrarenal factors influencing urodilatin secretion, high cephalic sodium and cardiac volume load, urodilatin secretion might also be regulated by an intrarenal sodium sensitive mechanism.

1-Methyl-3-isobutylxanthine↗
PubMed1996

Urodilatin secretion in salt-loaded Wistar rats.

The aim of our study was to investigate whether urodilation (URO, INN: ularitide) is present in rat urine and if URO excretion in the rat is influenced by dietary sodium intake. Therefore, three groups of Wistar rats were placed in metabolic cages where they received different sodium diets for 9 days (0.05%, 0.4%, and 8.0% NaCl, respectively). Food and water intake were determined by weight. At days -4, 2, 5, and 8 blood pressure was measured non invasively using the tail cuff method. After nine days rats were anesthetized and blood was drawn for serum electrolyte, plasma A-type natriuretic peptide (CDD/ANP-99-126), and plasma aldosterone concentration measurements. Using a highly specific antibody against URO combined with high performance liquid chromatography and gel chromatography, we were able to show that a URO-like substance of approx. 3.5 kD that is distinct from CDD/ANP-99-126, brain natriuretic peptide, and C-type natriuretic peptide, is present in rat urine. Sodium chloride loaded rats showed significantly increased urinary excretion rates of URO (p < 0.001), chloride (p < 0.001), sodium (p < 0.001), and the fractional excretion of sodium (p < 0.001). In the plasma, sodium (p < 0.01) and chloride (p < 0.001) increased, while potassium, hematocrit, osmolality, plasma CDD/ANP-99-126, as well as glomerular filtration rate (GFR), and systolic blood pressure did not change. Since CDD/ANP-99-126 is believed to be a natriuretic peptide, it is suggested that CDD/ANP-99-126 might participate in the natriuresis due to high dietary sodium intake. In sodium-loaded rats, however, plasma CDD/ANP-99-126 remains unchanged, while URO excretion increases with sodium excretion, independent of GFR and blood pressure. We conclude that URO secretion is stimulated by dietary salt loading and might be involved in the regulation of water and electrolyte metabolism in the rat.

Aldosterone↗
PubMed1996

Isolation of human uteroglobin from blood filtrate.

The purpose of this study was to assess the possibility of isolating biologically active peptides from human blood using large volumes of blood filtrate, which are available from patients undergoing extracorporeal ultrafiltration because of renal insufficiency. This filtrate was submitted to six chromatographic separation steps, yielding one purified peptide which was completely analysed in its primary structure. It was found to be strikingly similar to proteins, described initially as rabbit uteroglobin (or blastokinin) and, more recently, from human bronchial lavage as the '10 kDa Clare cell protein', as well as from human urine as 'protein-1'. The natural molecule contains two chains of identical amino acid sequences of 70 residues which are arranged as an antiparallel dimer due to the disulphide bonds between two cysteines at positions 3 and 69. Mass analysis of the molecular forms yielded molecular weights from 15827 Da (non-oxidized form) to 15859 Da (bi-oxidized form). We conclude that this peptide isolated from the filtrate represents the human uteroglobin, and we demonstrate for the first time that this peptide may be involved as a humoral factor in reproductive or other physiological functions.

Amino Acid Sequence↗
PubMed1993

Colpocystodefecography.

PURPOSE: To assess, in one single procedure, a complete study of the female pelvis, including the Douglas pouch. METHODS: Colpocystodefecography (CCD) combines vaginal opacification, voiding cystography, and defecography. Three hundred examinations are reviewed. RESULTS: Thanks to the simultaneous visualization of the pelvic structures, CCD proved to be more useful than clinical evaluation to diagnose prolapses and particularly Douglas pouch hernias (enteroceles), the clinical diagnosis of which was missed in 93 of 111 cases. Moreover, in addition to morphologic and functional information, CCD brings about a new insight in the study of pelvic organs reciprocal influences, should they be positive (supporting function) or negative (external compression). Finally, significative pelvic surgery and particularly hysterectomy enhances greatly the risk of enteroceles. CONCLUSION: CCD is helpful in the preoperative staging, especially in the selection of the surgical procedure that will least likely predispose to possible late postoperative complications such as vaginal prolapses or enteroceles.

Adult↗
PubMed1989

Degradation of porcine brain natriuretic peptide (pBNP-26) by endoprotease-24.11 from kidney cortical membranes.

Porcine brain natriuretic peptide of 26 amino acid residues (pBNP-26) is inactivated by endoprotease-24.11 (EC 3.4.24.11) of kidney cortical membranes. In contrast to human alpha atrial natriuretic peptide/cardiodilatin (ANP/CDD) showing a single major cleavage within the disulfide-linked loop between Cys and Phe in position 7 and 8, pBNP-26 is cleaved at several sites. Although both pBNP-26 and ANP/CDD exhibit Cys-Phe peptide bonds at the corresponding positions this bond is not cleaved in BNP-26.

Amino Acid Sequence↗
PubMed1989

The heart is the center of a new endocrine, paracrine, and neuroendocrine system.

This review indicates that the heart is a polypeptide-producing organ which should be classified among the traditional endocrine tissues. Cardiac hormones have only been known for a few years, the discovery of their endocrine functions, however, occurred in the 1950ies when Gauer, Henry and Kisch observed specific physiological and morphological features of the heart atria indicative of an endocrine activity. Because of their basic effects many target organs involved in the regulation of body fluid pressure and composition are related to this endocrine organ located in the atrial appendages of the heart. The compact endocrine portion of the heart is built up by myoendocrine cells which form the functional endocrine units and produce a variety of polypeptide hormones called cardiodilatin (CDD) or atrial natriuretic polypeptide (ANP), which belong to one family. Also, co-storage of a partially homologous regulatory polypeptide called brain natriuretic polypeptide (BNP) occurs, as has been determined by immunohistochemistry and radioimmunoassay. CDD and/or BNP are found in numerous organs where they exert paracrine and neurocrine functions, e.g., in the brain, peripheral nervous system, kidney, and adrenal medulla. In these organs, a differential post-translational processing of cardiac polypeptides is observed, resulting in different functional activities according to discriminating receptor interactions and degrading metabolism. Some of the extra-auricular sites of synthesis and storage of CDD-like peptides are briefly mentioned. In summary the heart constitutes the center of a multilocal and multifunctional system of specific cardiac polypeptides of endocrine, paraneuronal, and neuronal character.

Animals↗
PubMed1988

Isolation and structural analysis of "urodilatin", a new peptide of the cardiodilatin-(ANP)-family, extracted from human urine.

Two major forms of cardiac peptides have been established in the last few years: (a) a prohormone of 126 amino acids (CDD/ANP-1-126) in the endocrine heart and (b) the circulating CDD/ANP-99-126 (= alpha ANP) in blood plasma. The method we applied earlier to isolate the circulating form of cardiodilatin from human blood was used to detect and analyze the biologically active, predominant form of the same polypeptide family excreted by the kidneys. Each step of the isolation procedure was followed up by a bioassay using an in vitro vascular smooth muscle relaxation test and a highly specific RIA against cardiodilatin (CDD-99-126) for the initial purification steps. The polypeptides excreted in 1000 l of normal human urine were adsorbed to 2.5 kg of alginic acid, and after elution and lyophilization processed on a G-25 Sephadex column. The obtained crude polypeptide fractions were applied to ion-exchange chromatography. Thereafter four steps of HPLC were carried out to purify the polypeptide which was the suggested form of cardiodilatin (CDD) in human urine. The amino acid analysis and gas phase sequence analysis showed that the main form of urinary cardiodilatin is a 32 amino acid residue containing molecule, cardiodilatin-95-126. The molecule is N-terminally extended compared to the circulating CDD-99-126. This suggests that the analyzed urinary peptide is not the residual plasma form, filtrated and renally cleared from blood, but probably a polypeptide produced and processed in the kidney tubules and cleaved by a different postranslational process. Therefore, this vasorelaxant polypeptide is called urodilatin.

Amino Acid Sequence↗
PubMed1988

Urodilatin (CDD/ANP-95-126) is not biologically inactivated by a peptidase from dog kidney cortex membranes in contrast to atrial natriuretic peptide/cardiodilatin (alpha-hANP/CDD-99-126).

Atrial natriuretic peptide (CDD/ANP-99-126) is rapidly inactivated by a membrane preparations from dog kidney cortex. Inactivation occurs by cleavage of the ring structure in the position between Cys-105 and Phe-106. A unique proteolytic product separated by HPLC on reverse-phase column appears as a single peak which elutes prior the intact peptide. In contrast, CDD/ANP-95-126 (urodilatin) which is released from the kidney is not destroyed by proteolysis using an identical membrane preparation.

Animals↗
PubMed1987

Relaxation of smooth muscle by cardiodilatin/atrial natriuretic peptide is inhibited by cAMP-dependent phosphorylation.

Cardiodilatins/atrial natriuretic peptides (CDD/ANP) exhibit a common amino acid sequence: Arg101-Arg102-Ser103-Ser104. Cyclic AMP-dependent phosphorylation of Ser104 of atrial peptides with [gamma-32P]ATP enables rapid identification of cardiac hormones. The biological activity of in vitro phosphorylated cardiodilatin (CDD-28/alpha-hANP) is dramatically altered compared to the unphosphorylated peptide: the vaso-relaxant effect of cardiodilatin 28 is inhibited upon phosphorylation.

Animals↗
PubMed1987

Isolation of bovine cardiodilatin by fast protein liquid chromatography and reversed-phase high-performance liquid chromatography.

Cardiodilatin (CDD), a polypeptide exhibiting vasorelaxant and diuretic natriuretic bioactivity, was isolated from bovine atria. The isolation procedure reported here is different from that originally used for the purification of porcine and bovine CDD. Instead of cation-exchange chromatography on Fractogel TSK-CM 650 S and several purification steps on different high-performance liquid chromatographic (HPLC) columns, it is now possible to obtain CDD-88 by an automated fast-protein liquid chromatography system for repeated injections and a motor valve as fraction collector and only one final step of reversed-phase HPLC on a TSK-ODS-120T column.

Amino Acid Sequence↗
PubMed1987

Suicidal contact gunshot wounds to the head with .38 Special Glaser Safety Slug ammunition.

Glaser Safety Slug TM ammunition is a uniquely designed, essentially prefragmented ammunition. Tests performed by the U.S. Justice Department demonstrated that the ammunition possesses high kinetic energy, high relative incapacitation index (RII) and poses a very low risk to bystanders because of its total loss of kinetic energy in the target. Despite having been manufactured since 1974, no deaths from this ammunition have been previously reported. The authors herein describe the first three reported human deaths.

Adult↗
PubMed1986

Isolation and structural analysis of the circulating human cardiodilatin (alpha ANP).

A new method was applied to isolate a polypeptide hormone from human blood. The polypeptides from 1,000 1 of hemofiltrate with a molecular weight lower than 20 kDaltons were adsorbed to 2.5 kg alginic acid, then eluted, precipitated, and desalted on a G-25 Sephadex column, thus obtaining a crude lyophilised plasma polypeptide extract. These polypeptides were further submitted to ion-exchange chromatography. Thereafter, two steps of HPLC were carried out to purify a distinct polypeptide which was the circulating form of cardiodilatin (CDD) in this case. The amino acid analysis, C-terminal enzymatic cleavage by carboxypeptidase A, and sequence analysis showed that the only form of circulating cardiodilatin is the 28 amino acid residue containing molecule, cardiodilatin-99-126 cleaved from the C-terminus of cardiodilatin-126 and identical with alpha-ANP (alpha atrial natriuretic polypeptide). Other bioactive molecular forms of the polypeptide hormones of the cardiodilatin family were not detected in the hemofiltrate. The isolation procedure was followed up by a bioassay using in vitro vascular smooth muscle relaxation.

Amino Acid Sequence↗
PubMed1986

Cardiac hormones: morphology and biochemistry.

The heart contains, in addition to its myocardial working cells and the conductive system, a specialized endocrine part localized mainly in the atrial appendage which is predominantly made up by myoendocrine cells. The ultrastructural and immunocytochemical analysis of myoendocrine cells show a specialized secretory apparatus involved in the synthesis and secretion of cardiac hormones. These cardiac hormones are synthesized and processed in the myoendocrine cells as follows: a preprohormone is found in the rough endoplasmic reticulum, the prohormone cardiodilatin/gamma-atrial natriuretic polypeptide (CDD/ANP) is processed in the Golgi apparatus and stored in the secretory granules. The circulating peptide, cardiodilatin 99-126/alpha-ANP, is the C-terminus of this preprohormone which is released as the active circulating form into the blood stream.

Animals↗
PubMed1984

The auricular myocardiocytes of the heart constitute an endocrine organ. Characterization of a porcine cardiac peptide hormone, cardiodilatin-126.

A peptide hormone was extracted from the porcine right atrium following a bioassay for differential vasorelaxant effects on smooth muscle strips from aorta and renal and inferior mesenteric arteries. The isolation procedure included several steps of gel-permeation and ion-exchange chromatography, and high performance liquid chromatography. During the isolation procedure, other peptides of smaller molecular weight were also found, which, in relation to cardiodilatin-126 (CDD-126), are shorter at their N-terminal. Among these, CDD-88 has also been isolated and characterized, and has been established as a prominent member of the cardiac hormone family. The N-terminal and C-terminal segments of the 126 amino acid-containing molecule were synthesized and used to raise region-specific antibodies. The natural peptide was then localized within myoendocrine cells of the right atrium where specific atrial granules are located. Renal effects of cardiodilation were studied in conscious dogs and showed strong diuretic and natriuretic activities. According to our functional studies, cardiodilatin-126 and cardiodilatin-88 possess qualities of a significant hormone family regarding the regulation of extracellular fluid volume and blood pressure.

Amino Acid Sequence↗
PubMed1983

The right auricle of the heart is an endocrine organ. Cardiodilatin as a peptide hormone candidate.

A new polypeptide hormone candidate regulating vascular smooth muscle function was extracted from porcine atrial tissue. The purification steps were followed by a bioassay. The hormonally active substance has been analyzed and found to be a small polypeptide exhibiting a molecular weight of about 7500 and is named "cardiodilatin" (CDD). Further chemical data on this new hormone will be published elsewhere. A partial amino acid sequence of cardiodilatin is offered and shows that among the well known hormones or neuropeptides, none exhibit a homologue partial sequence.

Amino Acid Sequence↗