Search PubMed⌕ Search

Biomedical subjects

S Vogel

Publications and source records attributed to S Vogel.

At least 145 records · Page 8Linked to original sources
PubMed1981

Cloned fragments of human adenovirus type-12 DNA.

The following restriction endonuclease fragments of human adenovirus type 12 (Ad12) DNA have been cloned in plasmid or bacteriophage lambda vectors using standard protocols: the EcoRI-A*, -B, -D, -E, and -F fragments, the BamHI-B, -C, -D, -F, -G, -H, and -I fragments, the HindIII-F and -I fragments, and the PstI-A, -D, -F, -G, and -H fragments. The EcoRI-A* fragment comprises the right terminal 5 kb of Ad12 DNA including the terminal 143 bp.

Adenoviruses, Human↗
PubMed1981

[Microsurgical anastomoses between extra- and intracranial arteries (author's transl)].

86 patients underwent microanastomoses to branches of the anterior-, medial-and posterior cerebral arteries and the inferior cerebellar artery. Intraoperative electromagnetic measurement yielded a mean flow of 33 ml/min with a velocity of 11 to 54 cm/s. The brain circulation increased by a percentage of 38. In a percentage of 90 postoperative angiographic controls turned out anastomoses to be patent. By this surgical technique unilateral brain circulation can be improved significantly.

Arteries↗
PubMed1980

Overdrive suppression of automaticity in cultured chick myocardial cells.

Overdrive suppression in automatic cells and postdrive hyperpolarization in quiescent cells were examined in cultured embryonic chick heart cells. Cells were enzymatically separated from 3-day-old whole hearts and from 16-day-old atria and ventricles. The dispersed cells were allowed to reaggregate into small spheres (aneural) and maintained in culture for 1--4 wk. Quiescent reaggregates (all ventricular reaggregates and some of the atrial) demonstrated postdrive transient hyperpolarization of up to 5 mV. The spontaneously beating reaggregates (some of the atrial and all of the 3-day-old hearts) demonstrated overdrive suppression of automaticity. The faster the predrive spontaneous firing rate, the shorter was the overdrive suppression period. Prolongation of the drive period increased the duration of the overdrive suppression. The time courses of recovery from both overdrive suppression and postdrive hyperpolarization were similar. Atropine (10(-5) M) did not affect the phenomena. Ouabain (10(-6) M) reduced the postdrive hyperpolarization and shortened the duration of overdrive suppression. It was concluded that overdrive suppression and postdrive hyperpolarization a) occur in cultured chick ventricular and atrail cells; b) occur in early embryonic stages of development; c) occur independently of cholinergic receptors; d) are dependent on stimulation of an elecrogenic Na-K pump.

Animals↗
PubMed1980

[Intraoperative detection of parathyroid tissue by semiconductor electrodes (author's transl)].

With miniature semiconductor electrodes of high sensitivity and special shape it is possible to charakterize diverse tissues during operation. The measured radioactivity of phosphorus reflects its enrichment and storage in the parathyroid tissue. The findings of 5 patients in whom clinically hyperparathyroidism was strongly suspected and who underwent surgery are reported. We have successfully localized parathyroidea adenomas in 3 patients, in 2 cases no adenoma could be found the storage of phosphorus 32 was normal. In all measurements we achieved a complete agreement with histological findings.

Adenoma↗
PubMed1978

Yohimbine blockade of ionic channels in myocardial cells.

The effects of yohimbine, an alkaloid shown to have local anesthetic properties on nerve, were determined in isolated perfused chick embryonic (19--21-day-old) hearts. Effects on the fast Na+ channels were studied in hearts perfused with normal Ringer solution by using the maximal upstroke velocity (+Vmax) as an index of the inward current flowing during the rising phase of the normal action potential. Yohimbine (10(-5)--10(-4) M) depressed +Vmax and overshoot and prolonged the action potential. At 5 x 10(-4) M, yohimbine completely blocked the fast Na+ channels, since this dose abolished the action potential when Mn2+ (2 mM) was present to eliminate the slow Ca2+ current. Effects on the slow channels were studied in hearts in which the fast Na+ channels were voltage-inactivated by partial depolarization to about--40 mV with an elevated (25 mM) K+-Ringer solution or blocked by tetrodotoxin (TTX), resulting in loss of excitability. Isoproterenol (10(-6) M) restored excitability by inducing a slowly rising overshooting electrical response (the "slow response") that was accompanied by contractions. At low concentrations (10(-5)--10(-4) M), yohimbine enhanced the isoproterenol-induced slow response; yohimbine induced the slow response in the absence of isoproterenol, even in the presence of a beta-adrenergic blocker. In contrast, at high concentrations (10(-3) M), yohimbine markedly depressed or blocked the slow response. Consistent with this dual action, yohimbine exerted a small positive inotropic action at low doses in hearts perfused with normal Ringer solution and exerted a considerable negative inotropic action at high doses, causing complete blockade of the contractions within 20 min. Cultured reaggregated cells obtained from chick embryo (15--17 day-old) ventricles showed a similar response to yohimbine in that both the normal action potentials and the slow responses were abolished. It is concluded that yohimbine exerts a local anesthetic-like action on myocardial cells, since both fast and slow channels were blocked, but the fast channels were more sensitive to yohimbine.

Action Potentials↗
PubMed1977

Oxygen affinity of hemoglobin in postmenopausal women.

In a group of 12 postmenopausal women the P50-value (i.e. half saturation tension of oxygen) and other parameters of the red blood count were determined and compared with values of a male group of the same age. A small but significant difference could be found between the hematocrit values but no other values differed. In particular, the sex difference in oxygen affinity reported earlier does not exist in men and women on this age group.

Adult↗
PubMed1977

Current-induced flow through living sponges in nature.

Flow velocities through and immediately adjacent to the excurrent openings (oscula) were measured in eight species of marine sponges in their natural environments with a two-channel thermistor flowmeter. Flow through the oscula was positively correlated with both normal and artificially augmented ambient flow in both normally pumping and inactive animals. These results indicate that the passage of water through these sponges is, in part, induced by ambient currents.

Animals↗
PubMed1977

Blockade of myocardial slow inward current at low pH.

The effect of low pH on the slow cationic inward current was studied in isolated perfused embryonic chick ventricles (16-21 days old). In order to study the slow current, the fast Na+ current was inactivated by partial depolarization to about -40 mV by elevation of K+ (25 mM). Subsequent exposure of the tissue to catecholamines or methylxanthines allowed slowly rising overshooting electrical responses (the "slow response") with with accompanying contractions to be elicited by electrical stimulation. These slow responses are insensitive to tetrodotoxin and are Na+- and Ca2+-dependent. It was found that the isoproterenol- and caffeine-induced slow responses were abolished at about pH 6.1; 50% inhibition occurred at about pH 6.5. The rate of rise of the normal action potential, which is dependent on a fast Na+ current, was only slightly affected at these same pH levels; however, electromechanical uncoupling occurred, as expected from inhibition of the slow current. Therefore, the slow current was blocked at an acid pH that did not block the fast Na+ current.

Action Potentials↗
PubMed1977

[Arteriomesenteric obstruction of the duodenum (author's transl)].

Survey of the clinical and diagnostic treatment of arteriomesenteric obstruction. Report on 4 cases of chronic obstruction and 2 cases of acute occlusion of the duodenum due to the root of mesenteric vessels. Indication of operation. Recommendation of retrocolic side-to-side duodenojejunostomy.

Adult↗
PubMed1976

Mechanism of the histamine-induced positive inotropic action in cardiac muscle.

Histamine, a positive inotropic agent which elevates cyclic AMP, was tested for ability to induce Ca2+ channels in 3 preparations of embryonic (16-day-old) chick ventricular myocardial cells whose fast Na+ channels were blocked by tetrodotoxin or voltage inactivated in 25 mM K+. In such inexcitable cells, histamine (10(-6)M) rapidly (1-3 min) induced slowly rising, overshooting, plateau-like responses accompanied by contractions. Mn2+, D600, or H2-receptor blocking agents abolished the slow responses. These results suggest that the positive inotropic action of histamine, like that of catecholamines, is mediated by an increased availability of slow Ca2+ channels.

Action Potentials↗