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Biomedical subjects

M Frey

Publications and source records attributed to M Frey.

At least 217 records · Page 12Linked to original sources
PubMed1985

Experimental basis of the long-term therapy of arterial hypertension with calcium antagonists.

In vascular smooth muscle (as in myocardial fibers) a transmembrane supply of Ca++ ions is required for active tension development. In consequence, Ca++ antagonists, which restrict transmembrane Ca++ delivery, possess a wide scope of action against practically all types of vasoconstrictor or spastic reactions on coronary, pulmonary, cerebral, renal or mesenteric arteries. Another important target of Ca++ antagonists is the resistance vessels of systemic circulation in both animals and humans. Thus, Ca++ antagonists are successfully used for the treatment of acute hypertensive crises as well as for long-term antihypertensive therapy. Spontaneously hypertensive rats (SHRs) also respond to suitable Ca++ antagonists with a dramatic fall in blood pressure. The acute spasmolytic effects of Ca++ antagonists can be directly visualized by ophthalmoscopic examination of the arterioles in the ocular fundus. In untreated SHRs these arterioles are always heavily constricted, and aneurysm-like luminal protuberances develop. In contrast, after 1 adequate Ca++ antagonist dose, blood pressure instantaneously falls to its normal level while the retinal arterioles dilate. A further important effect of Ca++ antagonists that we have demonstrated in experiments on SHRs is the prevention of progressive arterial Ca++ overload, which otherwise produces severe calcinotic or arteriosclerotic damage of the arterial walls. However, with the help of Ca++ antagonists, arterial integrity can be totally preserved. Interestingly, this anticalcinotic arterial protection by Ca++ antagonists may also manifest itself independent of any blood pressure change. This is true of arterial calcinosis in normotensive rats because of advanced age, alloxan diabetes or intoxication with overdoses of vitamin D3, dihydrotachysterol or nicotine.

Animals↗
PubMed1985

[Risk profile and prognosis after myocardial infarct complicated by ventricular fibrillation].

In a prospective series of 190 patients under the age of 70 with a first myocardial infarction, the risk profile for ischemia, heart function and arrhythmias was investigated at the time of hospital discharge. Fifteen of these 190 patients had had ventricular fibrillation within 24 hours after admission which could be converted into sinus rhythm. In comparison, patients with ventricular fibrillation had a significantly larger infarct as estimated with the thallium-defect score (11.0 +/- 5.8 vs. 7.3 +/- 5.4; p less than 0.02)). In addition, left ventricular ejection fraction at rest was lower, at 42.7 +/- 17.4% compared to 50.0 +/- 14.0, but the p-value reached only 0.07. Persistent arrhythmias and ischemia were not significantly different in the two groups. In the first year after infarction none of these 15 patients died, compared to 8/175 patients.

Adult↗
PubMed1985

Time course of alterations in muscle transfers with microneurovascular anastomoses. An experimental study in the rectus femoris muscle of the rabbit.

The time course of alterations in muscle transfers with microneurovascular anastomoses was studied in 17 rabbits. The left rectus femoris muscle was transferred to the right side. For comparison, in some animals the right rectus femoris muscle was transferred from the right to the left side, but without vascular repair. Two, seven, 14, 21, and 30 days after transfer, the electric excitability, macroscopic appearance, histology, histochemistry, ultrastructure, and activity of muscle enzymes were assessed. In the transfers with microneurovascular anastomoses, almost all muscle fibers survived. Alterations were limited to those typical of a denervation-reinnervation process. Contrary to this, only a few atrophic fibers survived in the periphery of the transfers without vascular repair. By far, the greater central part underwent necrosis. A considerable amount of connective tissue developed. These results clearly show the functional superiority of microsurgically vascularized muscle transfers over those without vascular anastomoses. Excellent functional recovery is possible because the process of complete degeneration and consecutive regeneration, with inevitable augmentation of connective tissue, is prevented by the performance of vascular anastomoses.

Anastomosis, Surgical↗
PubMed1985

[Sonographic determination of spinal canal width. Comparison of computed tomography, myelography and conventional roentgen study of the lumbar spine].

Sonographic evaluation of the width of the spinal canal is inferior compared to CT or myelography, concerning accuracy and especially quantity of information received. The advantage of sonography is the lacking of X-ray exposure, the non-invasive procedure and the low cost of apparatus and operational time. For these reasons sonography is favoured as a screening method in detecting spinal canal stenosis in a group whose handicap was largely occupational or sport-related.

Female↗
PubMed1985

[Diagnostic approach in tumor patients with non-specific upper abdominal complaints].

The authors demonstrate on the basis of several observations of perigastric space-occupying growths in malignoma patients that x-ray examination of the stomach via mucosa and double-contrast imaging yields results of greatest diagnostic value in non-specific upper abdominal complaints. Supplementary diagnostic tools--but by no means competing methods--are often supplied by computed tomography and sonography. In case of extensive infiltration of the gastric wall, gastroscopy is indicated as an additional means to obtain confirmation by biopsy.

Abdominal Neoplasms↗
PubMed1985

[Free muscle transplantation].

To survey the current use of free muscle transplantation in the German speaking part of Europe, a questionnaire was sent to all Replantation Centres in 1982/1983. The answers revealed that micro-neurovascular muscle transplantation for functional use is still an uncommon procedure. Its use in facial palsy, in the sphincter region and in reconstructive procedures in extremities is emphasized and postoperative healing and functional improvement is shown in a diagram. The follow-up period is too short to discuss functional improvement in detail. Regarding our own cases, we are quite impressed by the result of free microneurovascular muscle transplantation in unilateral irreversible facial palsy patients, but are unable to prove the final result in extremities because of short observation time.

Adult↗
PubMed1984

[Possibilities in the future application of calcium antagonists. Is the prevention of blood vessel calcinosis possible?].

One of the most important effects of the new pharmacological family of Ca-antagonistic drugs is the prevention of deleterious myocardial Ca overload which is the decisive etiological factor in the production of cardiac necroses, as for instance b-adrenergic overstimulation. However, at an advanced age, also in the human arterial walls, cytotoxic degrees of Ca overload are reached, which probably play an important role in the pathogenesis of arteriosclerotic lesions. It is interesting that severe diabetics and heavy smokers exhibit a much faster progression of age-dependent arterial calcinosis than normal human subjects. In rats the Ca antagonists verapamil and diltiazem not only prevented arterial calcinosis due to overdoses of vitamin D and dihydrotachysterol, but also counteracted age-dependent Ca accumulation. Most impressive effects were also obtained in spontaneously hypertensive rats; chronic oral treatment with nifedipine and other 1,4-dihydropyridines as well as with verapamil kept both blood pressure and Ca content of the arterial walls (aorta, A. mesenterica) in the normal range. Our findings nourish the hope that suitable Ca antagonists can possibly interfere with arterial calcinosis also in humans, thus bearing a new vasoprotective indication.

Animals↗
PubMed1984

The isolation, propagation and characterization of tissue-cultured equine rotaviruses.

From 105 field cases of diarrhea in neonatal or young foals, rotavirus was detected by electron microscopy (EM) and/or by enzyme-linked immunosorbent assay (ELISA) in the feces of 65 foals on 16 different premises. ELISA was performed with Rotazyme test kits developed by Abbot and Company for the detection of rotaviruses. Twenty-four field isolates from the feces of diarrheic foals with equine rotavirus infection as ascertained by EM were placed in MA-104 cell cultures after pretreatment of the viral suspension with 10 micrograms ml-1 of trypsin and incorporation of 0.5 micrograms ml-1 or 1 microgram ml-1 of trypsin in Earle's minimal essential medium (MEM), 2% lactalbumen hydrolysate, and antibiotics. The isolates that replicated in cell culture produced varying degrees of cytopathic effect. After the 24 isolates had been transferred 5 or 7 times in cell culture, viral particles were observed in 17 by EM, and 22 had positive ELISA tests as determined by visual color chart and spectrophotometric readings. Concentrated tissue-cultured viral antigen of 9 isolates fixed complement using Nebraska calf diarrhea rotavirus calf antiserum while four isolates gave negative results. The same 13 tissue-cultured viral suspensions failed to fix complement using reovirus antiserum. The 9th passages of two isolates (EID1 and EID2) yielded titers of 10(4.45) ml-1 TCID50 and of 10(4.95) ml-1 TCID50, respectively, as measured by cytopathic effect. After 13 tissue-cultured passages, 2 other isolates, EID3 and EID4, each had titers of 10(6.2) ml-1 TCID50 and of 10(5.95) ml-1 TCID, respectively. Cytoplasmic or intranuclear inclusions were not seen in any cells of the MA-104 infected cell cultures. Small, but distinct, plaques in MA-104 cell cultures were produced by the EID1 isolate. Polyacrylamide gel electrophoresis tests of EID1 and EID2 isolates at the 9th cell passage and EID3 and EID4 isolates at the 13th cell passage each showed that the RNA genome had 11 segments with a migrating pattern that was identical for each isolate and characteristic of rotaviruses. These 4 equine tissue-cultured isolates when tested by ELISA, utilizing a monoclonal antibody serum pool that cross-reacted with many rotavirus isolates, each gave positive values comparable to rotavirus antigen controls.

Animals↗
PubMed1984

The chronically stimulated muscle as an energy source for artificial organs. Preliminary results of a basic study in sheep.

In 5 adult sheep the psoas muscle of one side was electrically stimulated through the muscle nerves with an implantable stimulation unit for more than 5 weeks. In the final experiments the isometric tetanic tension of the stimulated muscles was reduced to 50-70% of the contralateral normal muscle. The use of only 15 Hz as a stimulation frequency led to a transformation of the originally fast muscle into a slow muscle with more resistance to fatigue. Future application of the chronically stimulated psoas muscle for driving artificial organs is discussed.

Animals↗
PubMed1984

[Specific mechanism of action of calcium antagonists in the neutralization of experimental coronary spasms].

In vascular smooth muscle cells as in myocardial fibres, a transmembrane supply of Ca ions is required for activation of the contractile system. This is especially obvious in the vasculature of the great subepicardial coronary stem arteries which rapidly lose contractility upon extracellular Ca withdrawal. Consequently, in this special section of the coronary bed, even minute concentrations of calcium antagonists, by interference with transmembrane Ca++ influx, are capable of a spectacular suppression of contractile vascular smooth muscle performance. Moreover, in the extramural coronary vasculature - in contrast with most systemic arteries - the scope of the vasodilator and spasmolytic effects of calcium antagonists is particularly broad. This means that calcium antagonists produce a nearly uniform cessation of both tonic and phasic coronary responses regardless of whether different vasoconstrictors, receptors or pathways of Ca++ delivery are involved. Thus, our animal experiments as well as successful clinical trials highlight the outstanding efficacy of calcium antagonists in neutralizing all types of extramural coronary artery spasm. This action of calcium antagonists seems to be the predominant haemodynamic factor in relieving or preventing acute ischemic episodes especially in coronary heart disease with spastic components.

Acetylcholine↗
PubMed1984

[Operative technic in muscle transplantation with microneurovascular anastomoses based on animal experiment studies].

The influence of the transient ischemia during free muscle transplantation with microneurovascular repair was studied in the rectus femoris muscle of the rabbit, as well as the effect of denervation and reinnervation by nerve suture. Both factors, ischemia and nerve suture, were taken together in a separate series. The functional results of the different kinds of reinnervation by nerve suture, by nerve implantation and by muscular neurotisation were compared. The possibility to use a motor nerve elongated to the contralateral side by nerve grafting was tested. In a further series the effect of changes of the initial tension of the muscle during the transplantation was clarified. These isolated factors were compared with the real transplantation from the left to the right side. As the most representative parameter for function the maximal tetanic tension was chosen for evaluation. Our results show that the following considerations in the operative technique are significant. To shorten the time of ischemia the donor and recipient area should be prepared for transplantation at the same time, the recipient vessels should be elongated before the muscle transplant is taken off, and the arterial anastomoses should be performed before the venous. For reinnervation of the muscle transplant nerve suture is more successful than nerve implantation. Both methods can be combined to make good use of all the potential of reinnervation. The muscular neurotisation should be used only in the face and for sphincter reconstruction. A contralateral source of reinnervation is useful in the face, but it is not in the extremities. The restitution of the original initial tension of the muscle after transplantation is of great importance.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1984

[Reconstruction of grip function in cases of a fingerless or missing hand].

In two cases a grip reconstruction by double toe-to-hand transfer is demonstrated. In the first patient all fingers of the left hand were amputated at the metacarpo-phalangeal joint level. The second and the third finger were reconstructed by transplantation of the second toe from the left foot and the third toe from the right foot. The distal and middle phalanx of the transplanted third toe had to be re-amputated because of mummification two weeks after the transplantation and was covered with a groin flap. Good function of the newly formed grip could be demonstrated. The second patient was a 21-year old man with amputation of both hands. Grip reconstruction in the right lower arm was performed by transplantation of the second toe of each foot together with a metatarsal bone and a dorsalis pedis flap. One year after the operation the follow-up study demonstrated good function of the newly formed hand. The patient is able to use his two new fingers during daily life mainly to hold small objects. The sensation and the range of movement of the newly formed right hand are demonstrated and discussed.

Adult↗
PubMed1983

Is a crossover to the contralateral side by nerve transplants a satisfactory source for reinnervation of a muscle transplant? An experimental study in the rectus femoris muscle of the rabbit.

In ten rabbits the nerve branch to the left rectus femoris muscle was prolonged to the contralateral side by a nerve graft. Three months later the distal end of the transplant was connected to the transsected nerve branch to the right rectus femoris muscle. Nerve biopsies were taken from the muscle nerve, the nerve graft at the time of grafting and from the distal end of the nerve graft immediately before nerve suture in the second operation. Six months after the second operation the final assessment of muscle function and of the histology of the muscle and of the muscle nerve was performed. The functional results of the rectus femoris muscle reinnervated by a crossover nerve graft ranged between 6% and 56% of a normal standard muscle and seemed to be insufficient to justify a clinical use for muscle transplant reinnervation in the extremities. The histological findings also confirmed the basic possibility of elongating a motor nerve by nerve grafts, but the second nerve suture, the interposition of a long nerve graft, and the obviously changed reflex system probably caused a moderate and unpredictable muscle function.

Animals↗