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Biomedical subjects

E Weihe

Publications and source records attributed to E Weihe.

At least 127 records · Page 7Linked to original sources
PubMed1984

Dopamine-beta-hydroxylase-, neurotensin-, substance P-, vasoactive intestinal polypeptide- and enkephalin-immunohistochemistry of paravertebral and prevertebral ganglia in the cat.

Para- and prevertebral ganglia of the cat were investigated for immunoreactivity (IR) against neurotensin (NT), vasoactive intestinal polypeptide (VIP), substance P (SP) and enkephalin (ENK). Dopamine-beta-hydroxylase-(DBH)-IR was studied in consecutive sections to correlate the distribution of noradrenergic/adrenergic neurons with that of peptidergic nerve fibres and cells. In paravertebral (cervical and thoracic) ganglia, NT-IR or ENK-IR nerve fibres were seen in areas in which DBH-IR fibre networks also occurred. NT-IR varicosities were often in close contact with perikarya of principal ganglionic cells on which DBH-IR varicosities also terminated. Such an association was rarely seen between ENK-IR and DBH-IR fibre baskets. NT-IR and ENK-IR fibre baskets were not found to occur around the same principal ganglionic cell. The distribution of VIP-IR and SP-IR nerve fibres did not coincide with that of DBH-IR fibres. In prevertebral ganglia (celiac-superior mesenteric and inferior mesenteric) DBH-IR or VIP-IR varicosities surrounded the majority of principal ganglionic neurons. ENK-IR or SP-IR fibres were closely associated with only a minority of the neurons; NT-IR networks were rather sparse. Some principal neurons were approached by DBH-IR fibres and by different peptide-IR fibres. In paravertebral ganglia some principal ganglionic cells contained VIP-IR, a few of which were also surrounded by NT-IR varicosities. VIP-IR perikarya in prevertebral ganglia were extremely rare. No NT-IR, SP-IR or ENK-IR principal ganglionic cells were found. Glomus-like paraganglionic cell clusters in paravertebral and prevertebral ganglia exhibited DBH-IR cell bodies.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1984

Reduction of coronary reserve: a mechanism for angina pectoris in patients with arterial hypertension and normal coronary arteries.

The pathogenesis of angina pectoris in patients with left ventricular hypertrophy secondary to arterial hypertension and with normal coronary arteries remains uncertain. We measured coronary blood flow (argon method) in 12 control subjects and in 16 patients with arterial hypertension at rest and after intravenous administration of dipyridamole (0.5 mg/kg). In the patients with arterial hypertension, coronary blood flow response to dipyridamole was markedly reduced (p less than .001 as compared with control values). During coronary vasodilation there was a linear correlation between coronary resistance and left ventricular end-diastolic pressure (r = .67, p less than .001). Left ventricular catheter biopsy specimens did not reveal alterations in myocardial microvasculature. These findings suggest that reduction of coronary reserve may be an important contributor to the pathogenesis of angina pectoris in these patients.

Adult↗
PubMed1984

Morphologic investigation of coronary arteries subjected to hypertension by experimental supravalvular aortic stenosis in dogs.

A sustained and gradual development of hypertension in coronary arteries of 16 foxhounds was induced by afterload stress with supravalvular aortic stenosis. Dogs were perfusion fixed after 4 months and 1 year of stenosis for morphologic analysis of coronary arteries with scanning electron microscopy, transmission electron microscopy, and light microscopy. Mean prestenotic pressures and SD standard deviations in millimeters of mercury for perfusion-fixed foxhounds after 4 months were systolic 141 +/- 14, mean arterial 101 +/- 8, and diastolic 81 +/- 7, and after 1 year systolic 182 +/- 31, mean arterial 128 +/- 22, and diastolic 101 +/- 16. Scanning electron microscopy results of coronary arteries subjected to 4 months of hypertension show little change from normal coronary arteries. Only isolated cases of desquamating endothelial cells were seen directly proximal to ostia of coronary arteries. Transmission electron microscopy showed no ultrastructural changes in this banding group. In four of six foxhounds subjected to 1 year of hypertension, scanning electron microscopy observations of coronary arteries revealed one to five areas of endothelial denudation, typically oriented parallel to the longitudinal axis of the artery, a few cell diameters wide and 100 to 300 microns in length. These lesions were often seen to form narrow channels between two or more branching points, either in a continuous or in series fashion. Platelets, lymphocytes, granulocytes, and monocytes adhered to the subendothelial surface. Occasional denudations were oriented transversely to the longitudinal axis. Denudations were restricted to arteries greater than 1.2 mm in diameter. In the vicinity of denudation lesions, lymphocytes and monocytes adhered to endothelium showing alterations in cell size and shape. Transmission electron and light microscopy of this banding group showed breaks and duplication of the internal elastic lamina and smooth muscle proliferation in the intima. Focal areas of intimal inflammatory reactions, sometimes superimposed upon intimal proliferative changes, were noted in those areas exhibiting luminal cell adherence to endothelium. The results indicate that the morphologic equivalent of hypertension varies depending on the manner in which it is experimentally produced. The findings of intimal proliferation and late endothelial denudation give support to the response-to-injury hypothesis for the pathogenesis of atherosclerosis and suggest a mechanism for the role of hypertension as a risk factor.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1983

Neurotensin and substance P immunoreactive nerve endings in the guinea pig carotid sinus and their ultrastructural counterparts.

The carotid sinus of the guinea pig was analysed immunohistochemically for the occurrence of neuropeptides. Immunoreactivity (IR) for neurotensin (NT) and substance P (SP) is distributed in two different populations of nerve endings and varicosities. NT-IR fibers penetrate deeply into the tunica media of the elastic segment of the carotid sinus and form the large, branched lanceolate nerve terminals. Electron-microscopic investigations have revealed that the NT-IR varicosities correspond to the large afferent baroreceptor endings containing abundant mitochondria. SP-IR fibers are located mainly at the media-adventitial border. They seem to be correlated to dense-core, vesicle-containing varicosities identified in the electron microscope. Therefore, these fibers may constitute afferent and efferent perivascular plexus regulating the vascular tone of the carotid sinus wall.

Animals↗
PubMed1983

Characterization of opioid peptides in guinea-pig heart and skin.

Using reverse phase HPLC separations, and assay of eluate fractions in the mouse vas deferens, extracts of heart and skin from guinea-pigs were shown to contain several species of opioid-active material in low amounts (3-20 pmol/g as [Met5]enkephalin). Immunohistochemical studies revealed in the heart a small number of enkephalin-immunoreactive nerve fibres, particularly in cardiac ganglia and some small cells (paraganglionic cells, APUD cells). In the skin, enkephalin-immunoreactivity was confined to Merkel cells. Cardiac and cutaneous opioid peptides may modulate peripheral cardiovascular and sensory functions.

Animals↗
PubMed1983

Immunohistochemical localization of vasoactive intestinal polypeptide (VIP) in Merkel cells of various mammals: evidence for a neuromodulator function of the Merkel cell.

Since met-enkephalin-like substance has been demonstrated only in Merkel cells of some rodents but not of cat, dog, pig, and humans, Merkel cells of these species were analyzed by immunohistochemistry using a variety of different antisera for the occurrence of neuropeptides different from met-enkephalin. In various locations of all species investigated Merkel cells were found to be immunoreactive exclusively to vasoactive intestinal polypeptide (VIP) but not to any of the other antisera used. Thus, in mammalian Merkel cells, neuropeptides occur that are different from met-enkephalin. It is suggested that the Merkel cell-axon complex represents a complex regulatory system involving a presumptive receptor or modulator function whereby the Merkel cell may influence the threshold of the sensory nerve ending via release of a neuropeptide (VIP- or met-enkephalin-like material).

Animals↗
PubMed1982

Localization of neurotensin immunoreactive nerve fibers in the guinea-pig heart: evidence derived by immunohistochemistry, radioimmunoassay and chromatography.

By the use of the peroxidase-antiperoxidase technique guinea-pig hearts were investigated for the occurrence of neurotensin immunoreactivity. Neurotensin immunoreactive nerve fibers were found in distinct localisations in all hearts studied. In addition, neurotensin immunoreactive fibers were present in the adventitia of the ascending aorta, the aortic arch and the pulmonary trunk. All segments of the coronary vasculature exhibited a dense network of neurotensin immunoreactive fibers. This innervation pattern was most pronounced in the arterial portions. Neurotensin immunoreactive fibers occurred also in close contact with atrial and ventricular muscle cells. A particularly dense innervation by neurotensin immunoreactive fibers was present in the sinu-atrial node and in the atrio-ventricular node. The fibers were associated intimately with blood vessels as well as with nodal cells. In addition, neurotensin immunoreactive fibers were found in intracardiac ganglia. The presence of neurotensin-like immunoreactive material in the guinea-pig heart was demonstrated also by radioimmunoassay. The results of immunohistochemistry and radioimmunoassay were correlated. High performance liquid chromatographic analysis indicated that 20-30% of the total immunoreactivity co-chromatographed with guinea-pig or synthetic neurotensin. Evaluation of consecutive sections revealed different innervation patterns of neurotensin and substance P immunoreactive fibers. The findings suggest a neurotransmitter and/or neuromodulator function of neurotensin in the regulation of coronary circulation, of cardiac impulse generation and conduction, of heart muscle contractility and of cardiac reflex mechanisms. It is speculated that neurotensin might represent the efferent and substance P the afferent part of a cardiac regulatory system.

Animals↗
PubMed1981

[Angina pectoris syndrome in patients with normal coronary arteriograms (X syndrome) (author's transl)].

In 37 patients with typical exercise-dependent angina pectoris but with normal coronary arteriograms and normal left ventricular function at rest (X syndrome), the dipyridamole-induced dilatory reserve of the coronary vascular system was reduced significantly to about 50% of control values (P less than 0.001). There were no changes in the small vessels causing the reduced dilatory reserve, but ultrastructural changes in the mitochondria were demonstrable. In the patients with X syndrome there was a significant reduction of lactate extraction (P less than 0.05) after electrical atrial stimulation (150/min) and in most cases lactate production was demonstrable. In the control group the myocardial lactate uptake was unchanged. Left ventricular function in patients with X syndrome was normal at rest whereas during exercise it was significantly reduced (P less than 0.001). These results show that X syndrome consists of a particular form of ischaemic heart disease with still normal left ventricular function at rest, but disordered pump activity during physical stress.

Adult↗
PubMed1981

Peptidergic innervation of the mammalian sinus nodes: vasoactive intestinal polypeptide, neurotensin, substance P.

By the use of the peroxidase--antiperoxidase (PAP) technique in the sinus node of several mammalian species, vasoactive intestinal polypeptide (VIP), neurotensin (NT) and substance P (SP) immunoreactive structures were detected. VIP and NT as well as SP immunoreactive fibers were found in close association to the vasculature. While the innervation by SP immunoreactive fibers was restricted to blood vessels, VIP and NT immunoreactive fibers and varicosities were also in contact to nodal cells. Juxtanodal intracardiac ganglia and single intranodal ganglionic cells were supplied by VIP, NT and SP immunoreactive varicosities. In addition, VIP immunoreactive perikarya were present. The results suggest an involvement of VIP, NT and SP in the regulation of sinus node blood flow, in impulse generation as well as in extrinsic and intrinsic cardiac reflex mechanisms.

Animals↗
PubMed1981

Reduced coronary dilatory capacity and ultrastructural changes of the myocardium in patients with angina pectoris but normal coronary arteriograms.

Hemodynamic and metabolic studies were performed in 15 patients without heart disease (controls, group A), in 21 patients with typical stress-induced anginal pain but normal coronary and left ventricular angiograms (angina pectoris with normal arteriogram, group B), and in 10 patients with angiographically proved coronary artery disease (CAD, group C). Coronary dilatory capacity, determined by measuring total myocardial blood flow at rest and during maximal coronary vasodilatation (dipyridamole, 0.5 mg/kg i.v.), was markedly reduced in group B and C patients. In group B patients, left ventricular catheter biopsy specimens revealed no evidence of small-vessel disease, but did show histologic alterations of mitochondria. During atrial pacing, the control subjects showed no changes in myocardial lactate uptake, whereas in group B patients, myocardial lactate production occurred. In contrast to controls, patients in group B showed a significant decline in ejection fraction and circumferential fiber shortening during isometric exercise. These findings suggest that myocardial ischemia is the cause of angina pectoris in patients who have angina but normal coronary arteriograms.

Adult↗
PubMed1980

Intercellular junctions in the full term human placenta. II. Cytotrophoblast cells, intravillous stroma cells and blood vessels.

Intercellular junctions within the villous stroma and the cytotrophoblastic layer of the human full term placenta were investigated using thin sectioning and freeze-fracturing. Numerous maculae adherentes (desmosomes) were found between the cytotrophoblast cells and the syncytiotrophoblast. This junction type was also seen connecting adjacent cytotrophoblast cells. Large gap junctions were frequently observed in contact areas of perikarya or at processes of adjacent fibroblasts. They often exhibited a peculiar pattern of their particles on the P-face of the membrane. Small rows of junctional particles were found on the P-faces of interconnected smooth muscle cells and gap junctions frequently bridged myoendothelial and interendothelial contact zones. The significance of the junctional complexes is discussed in relation to functional systems within the villous stroma of the human full term placenta.

Blood Vessels↗
PubMed1980

Met-enkephalin-like immuno- and bioreactivity in extracts from skin containing Merkel cells.

Skin from the upper lip, bearing the sinus hair follicles rich in Merkel cells was investigated in guinea pig, rat, cat and rabbit by radioimmunoassay and radioreceptor assay. In all species Met-enkephalin-like immunoreactive material was extracted. In guinea pig this material had the same molecular size as Met-enkephalin. In a radioreceptor assay made with rat brain membranes extracts of guinea pig skin caused displacement of [3H]Met-enkephalin. The endogenous opioid of the size of Met-enkephalin contained in these skin extracts possibly derives from the Merkel cells.

Animals↗