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Biomedical subjects

M Havel

Publications and source records attributed to M Havel.

66 records · Page 4Linked to original sources
PubMed1985

Plasma fibronectin, albumin, IgM and total protein during cardiopulmonary bypass.

Plasma concentrations of fibronectin, albumin, total protein and IgM were measured in 14 male patients undergoing aorto-coronary bypass operations. Fibronectin and IgM concentrations fell to 55% of the preoperative values 5 minutes after start of the extracorporeal circulation, and the same percentages were encountered 5 minutes after the termination of bypass. The concentrations had recovered to 75% of the preoperative values by the end of the operation. The plasma concentration of albumin was 68 +/- 9% of the preoperative value after 5 minutes of bypass, 66 +/- 7% at the end of bypass, and 83 +/- 9% of the end of operation (significantly different from fibronectin and IgM, p less than 0.05; Wilcoxon's test for paired differences). No correlation was found between the duration of extracorporeal circulation and the post-bypass concentrations of any protein (Kendall correlation). It is concluded that the fall of fibronectin concentrations during cardiopulmonary bypass can be sufficiently explained by dilution, and that a specific consumption of fibronectin does not occur. The less marked decreases of albumin and total protein were probably due to infusion of plasma-protein solution, which is poor in fibronectin and IgM.

Adult↗
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↗
PubMed1983

Experimental free-muscle transplantation with microneurovascular anastomoses.

In 13 rabbits the rectus femoris muscle was freely transplanted from the left to the right side using microneurovascular anastomoses. About 7 months after surgery the muscle transplants were assessed functionally by force measurements. On the average, the transplanted muscles regained 55 percent of the maximal tetanic tension of unoperated, normal rectus femoris muscles, expressed as force per gram of muscle weight even 68 percent. After functional assessment, the muscles were weighed and then used for histologic, histochemical, planimetric, and biochemical evaluation. H&E-stained cross sections showed a high content of healthy muscle fibers; only some small atrophic and single fat cells were scattered over the cross sections. Good reinnervation over the sutured muscle nerve was confirmed by the type-grouping of muscle fibers in the NADH and myofibrillar ATPase staining. There was an excellent correlation between the functional results and the histologic picture as well as the content of choline acetyltransferase (CAT). A certain parallelism was found between the function of the transplants and the content of hexokinase, but none for the other estimated muscle enzymes, such as malate dehydrogenase (MDH), creatine kinase (CK), and lactic dehydrogenase (LDH). All enzyme levels were lower than in normal muscles. The results of this experimental series underline the utility of muscle transplantation with microneurovascular anastomoses to restore lost muscle function, even in the extremities, when strong forces are needed.

Animals↗
PubMedDate not supplied

In vitro activity of fosfomycin against methicillin-susceptible and methicillin-resistant Staphylococcus aureus.

The in vitro antibacterial activity of fosfomycin was compared to that of oxacillin, cefazolin, ceftriaxone and vancomycin against isolates of Staphylococcus aureus from patients treated at the University of Vienna General Hospital. Of 211 strains, 104 were methicillin-susceptible and 107 were methicillin-resistant. Fosfomycin inhibited over 90% of the strains at concentrations of less than or equal to 64 mg/l, independent of methicillin susceptibility or resistance. The minimal bactericidal concentrations (MBC) were one dilution above the minimal inhibitory concentrations (MIC). Vancomycin showed activity similar to fosfomycin while other beta-lactam antibiotics such as oxacillin, cefazolin and ceftriaxone were inactive against methicillin-resistant S. aureus. Fosfomycin at a high dosage seems to be a potential drug for the treatment of infections due to methicillin-resistant S. aureus.

Anti-Bacterial Agents↗
PubMedDate not supplied

Synthetic approach to analogues of 19-norsteroids with an acyclic side chain.

Racemic 14 beta-hydroxy-3-methoxy-8 alpha,9 alpha-1,3,5(10)-estratriene-17-one (I), obtained by total synthesis, was converted into a derivative with alkoxycarbonyl-ethylenic side chain, rac-(20E)-21-methoxycarbonyl-19-nor-8 alpha,9 alpha-pregna- 1,3,5(10),20-tetraene-3,14 beta-diol 3-methyl ether (XII) using two Wittig reactions. Analogous derivatives of 5 alpha-androstane were prepared as synthetic models. In the estrane series the stereochemistry of attachement of the side chain in position 17, biological activity of some compounds, and their chromatographic properties were investigated.

Chemical Phenomena↗
PubMedDate not supplied

Decreasing use of donated blood and reduction of bleeding after orthotopic heart transplantation by use of aprotinin.

Twenty patients undergoing orthotopic heart transplantation were randomized preoperatively to receive either the serine proteinase inhibitor aprotinin in a low dose (560 mg; n = 10) or a placebo (control group, n = 10) at the time of transplantation. Blood loss 24 and 48 hours after transplantation was significantly lower in the group treated with aprotinin (i.e., 510 ml vs 820 ml, p less than 0.01, and 690 ml vs 1000 ml, p less than 0.03, respectively. Accordingly, the aprotinin group required significantly less transfused blood in the first 48 postoperative hours 0 to 250 ml versus 0 to 1000 ml (p less than 0.04). Seventy percent of the patients treated with aprotinin underwent transplantation without the need of nonautologous blood, compared with only 30% in the control group.

Aprotinin↗
PubMedDate not supplied

Basic principles of cardioplegic management in donor heart preservation.

The primary factor limiting the number of heart transplantation performed is the lack of adequate donor hearts. One of the main factors contributing to this is the relatively short period a donor heart can be preserved. Clinical studies demonstrate that ischemic times over five hours lead to early heart failure after transplantation. A considerable increase in preservation time would be necessary to enlarge the donor pool. In spite of intensive research, it is not yet possible to increase the preservation period above four hours, which was achieved in 1978. An increase of the cold ischemia period to more than four hours without the risk of transplanted heart damage may only be achieved by improving cardioplegic management.

Cardioplegic Solutions↗
PubMedDate not supplied

Neopterin as a new marker to detect acute rejection after heart transplantation.

Neopterin is excreted at high levels in the course of activation of the immunologic system during allograft rejection or viral infection. This pteridine therefore may be considered as a specific indicator of T cell-mediated immunity. With radioimmunoassay we analyzed both serum and urine levels of neopterin in 43 patients after orthotopic heart transplantation. These data were correlated to the histologic finding at routine endomyocardial biopsies (EMB). In case of rejection (that is, grades I to II or more in EMB) serum levels of neopterin increased about 156% +/- 94% within 1 week before EMB, whereas urine levels increased about 215% +/- 137%. The most marked increase was seen 2.8 days before the corresponding EMB. The predictive value theory was used to elaborate the reliability of the correlation between an increase of neopterin levels and the occurrence of an acute rejection episode. With regard to serum levels, sensitivity and specificity were 0.872 and 0.815, respectively. The positive predictive value was 0.41 and the negative predictive value was 0.977. We found similar results in urine levels.

Acute Disease↗