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Biomedical subjects

R Mohr

Publications and source records attributed to R Mohr.

At least 91 records · Page 5Linked to original sources
PubMed1986

Negative right ventricular diastolic pressure after operation for pulmonary valve stenosis: the phenomenon and its relation to volume load and conal contraction.

The phenomenon of negative right ventricular diastolic pressure immediately after operation for relief of isolated pulmonary valve stenosis was investigated in 11 patients. Pressures in the right ventricle and pulmonary artery were measured with a catheter tip micromanometer. One patient had a negative right ventricular diastolic pressure before operation. At the end of operation right ventricular diastolic pressure was negative in all 11 patients. The greater the right ventricular hypertrophy, the lower were these diastolic pressures. Negative right ventricular diastolic pressure is thus common in patients after pulmonary valvotomy, but fluid administration may eliminate it. Negative right ventricular diastolic pressure may be the result of hypercontraction and reduced volume of the hypertrophied right ventricle after relief of right ventricular outflow tract obstruction.

Adolescent↗
PubMed1986

Changes in systemic vascular resistance detected by the arterial resistometer: preliminary report of a new method tested during percutaneous transluminal coronary angioplasty.

A recently developed apparatus provides on-line continuous monitoring of systemic vascular resistance (SVR) by means of simple computer analysis of the peripheral arterial waveform. The fundamental equation of this method is Ri = P'/(dP/dt), where dP/dt is the peak dP/dt of the peripheral arterial waveform, P' is the pressure at time of peak dP/dt, and Ri is a resistance index that bears a direct relation to SVR. Eleven patients undergoing percutaneous transluminal coronary angioplasty (PTCA) were studied to evaluate the changes in SVR associated with myocardial ischemia (angina detection). There were 49 balloon inflations, all of which were associated with an increase in Ri (from 38.4 +/- 12 to 81.2 +/- 36 X 10(-3) sec; p less than .01) and a decrease in dP/dt (from 2076 +/- 257 to 1327 +/- 326 mm Hg/sec; p less than .01). In 42 of the balloon inflations these changes were associated with electrocardiographic ST-T changes and in 23 it was also associated with anginal pain. When angina was present, a further increase in Ri (to 97.5 +/- 43 X 10(-3) sec; p less than .01) and a decrease in dP/dt (to 1218 +/- 338 mm Hg/sec; p less than .01) was observed. It was found that myocardial ischemia is associated with an increase in the resistance index and a decrease in dP/dt and can be detected by the resistometer.

Angioplasty, Balloon↗
PubMed1986

Effect of cardiac operation on platelets.

The effect of extracorporeal circulation on platelet count and size (mean platelet volume) was studied in 65 patients (nine bleeders and 56 nonbleeders). In addition to the above, in 20 of the patients platelet aggregation response to adenosine diphosphate, collagen, and ristocetin was measured. Platelet counts dropped postoperatively both in the bleeder and in the nonbleeder groups. The difference between them was not significant. However, the bleeders had a significantly lower mean platelet volume (7.7 +/- 0.84 versus 8.68 +/- 1.1 fl) and lower volume percentage of platelets in whole blood (0.075% +/- 0.02% versus 0.116% +/- 0.04%) (p less than 0.05) than the nonbleeders. None of the bleeders had a volume percentage of platelets in whole blood higher than 0.095%. All 20 patients studied for platelet functions had an abnormal postoperative aggregation response to adenosine diphosphate, collagen, and ristocetin. Three patterns of disturbed response to ristocetin were observed: grade I, delayed onset (14 patients); grade II, incomplete aggregation (five patients); and grade III, total lack of aggregation (one patient). All patients with delayed-onset response to ristocetin had a normal bleeding time, whereas the six patients with grade II and III responses had prolonged bleeding times and three of them had clinically significant bleeding. Factor VIII procoagulant activity, factor VIII-related antigen, factor VIII-ristocetin cofactor, and factor VIII two-dimensional electrophoresis were found normal, which suggests that the von Willebrand-like reaction to ristocetin observed in this study was caused by a defect in platelet membrane rather than by factor VIII changes.

Adolescent↗
PubMed1986

Platelet size and mass as an indicator for platelet transfusion after cardiopulmonary bypass.

Platelet count, mean platelet volume (MPV), and plateletcrit (PCT) were studied in 51 patients after cardiopulmonary bypass (CPB). MPV was significantly lower in 10 patients who developed postoperative bleeding (bleeders) compared to 41 with no significant bleeding (nonbleeders) (7.7 +/- 0.86 vs 8.5 +/- 1.2 fl, p less than .05). Postoperative platelet count was significantly lower in the group of bleeders (93.3 +/- 22.4 vs 127.5 +/- 43 X 10(9)/liters, p less than .02). A cutoff point of MPV or platelet count that would include bleeders and exclude nonbleeders could not be found due to the large overlap between the two groups. However, such a cutoff point does exist for PCT (PCT = total platelet mass). PCT was significantly lower among the bleeders (0.072 +/- 0.02% vs 0.108 +/- 0.036%, p less than .05) and a cutoff point of PCT less than 0.1% included all the bleeders and excluded 65% of nonbleeders. The low PCT and bleeding tendency can be corrected by platelets transfusion. In 15 patients (eight bleeders and seven nonbleeders) with low postoperative PCT (0.078 +/- 0.014), transfusion of 10 platelet units increased platelet count from 101 +/- 32 to 169 +/- 22 X 10(9)/liter, increased PCT to 0.128 +/- 0.2%, and stopped bleeding in all bleeders. A finding of PCT less than 0.1% after CPB is a clear indication for platelet transfusion in patients who develop post-CPB bleeding. This supports the observation that large platelets are more active than smaller ones, and that PCT, rather than PLT counts, predicts the risk of bleeding in patients with thrombocytopenia.

Adolescent↗
PubMed1985

A monoclonal antibody to the galactan from Helix pomatia snails recognizes beta-(1,6)-linked D-galactose residues.

Using the hybridoma technique, a series of four monoclonal antibodies to the galactan isolated from albumin glands of wine yard snails (Helix pomatia) could be generated. Characterization of the binding properties of one of these antibodies revealed a specificity for beta-(1,6)-glycosidically linked D-galactose residues. This could be demonstrated by reaction of the antibody with beta-(1,6)-D-galactans and by the D-galactose-inhibitable binding to group B streptococci of type II, which possess beta-(1,6)-linked D-galactose as immuno-determinant group.

Animals↗
PubMed1985

Biocuff--a new pressure device for infusion bags.

The Biocuff is a new pressure device designed to overcome the problems associated with use of pneumatic cuffs and spring-driven devices. It consists of three modular elements: a sleeve, an air sac, and a booster. The sleeve has a rigid back, which reduces the air volume required to compress the infusion bag. The booster applies constant air pressure until the bag is empty. The Biocuff is easy to handle and is quickly put into operation. It is most advantageous in situations requiring rapid infusion of large volumes of blood.

Blood Transfusion↗
PubMed1985

Parathyroid localization. Sonographic-surgical correlation.

Sonographic localization of enlarged parathyroid gland was performed in 37 patients suspected of hyperparathyroidism who underwent surgical exploration of the neck. Nine of those patients were clinically asymptomatic. Most of the others presented with urolithiasis. The sonograms were obtained by conventional and high resolution realtime (10 mHz). Of the 37 patients, 31 patients had a single adenoma, three patients had two adenomas, and two patients had hyperplasia. Analysis of the results has shown accuracy of 84 per cent. The sensitivity of the procedure was 79.5 per cent and the specificity was 98 per cent. The exact side and location of the enlarged parathyroid in relation to the thyroid gland was predicted in 91 per cent. The false-negative cases were due to abnormal location (gland in mediastinum or incorporated within the thyroid). The false-positive findings were all colloid cysts located at the periphery of the thyroid parenchyma. Preoperative confirmation and localization of enlarged parathyroid glands facilitated the decision for surgical intervention, especially in hypercalcemic asymptomatic patients and in high operative risk patients. The duration of operation and postoperative complications were significantly reduced.

Adolescent↗
PubMed1985

The effect of low-dose intravenous nitroglycerin on pulmonary hypertension immediately after replacement of a stenotic mitral valve.

The postoperative effect of infusion of nitroglycerin on pulmonary vasomotor dynamics was studied in 28 patients undergoing valve replacement for mitral valve stenosis. A 30% reduction in mean pulmonary arterial pressure (38.74 +/- 8.3 to 26.92 +/- 7.72 mm Hg, p less than .001) and a 48.4% reduction in pulmonary vascular resistance index (12.08 +/- 4.19 to 5.61 +/- 1.61 U/m2, p less than .001) were observed after nitroglycerin. While pulmonary driving pressure (mean pulmonary arterial pressure minus left atrial pressure) dropped by 50.8%, cardiac and stroke volume indexes increased by 25.5% and 24.2%, respectively. The ratio pulmonary/systemic vascular resistance decreased from 34.14% to 20.9% (p less than .001). There were no significant changes in mean systemic arterial pressure (86.89 +/- 13.5 to 83.5 +/- 9.3 mm Hg, p = NS) or heart rate (97.43 +/- 20.45 to 99.36 +/- 20.9 beats/min, p = NS); left and right atrial pressures decreased by 19.5% and 9.5%, respectively. Systemic vascular resistance index decreased by 18.8%. We conclude that low-dose infusion of nitroglycerin reduces the pulmonary vascular resistance in patients with pulmonary hypertension, and consequently results in improvement in immediate postoperative hemodynamics after replacement of a stenotic mitral valve.

Adolescent↗
PubMed1985

Speech rehabilitation outcome after Blom-Singer tracheoesophageal puncture.

This study evaluated speech rehabilitation outcome and length of training needed for laryngectomized patients who underwent the Blom-Singer tracheoesophageal (TE) puncture procedure. Preoperative patient selection criteria included: 1) acceptable stoma size, 2) adequate motivation and manual dexterity, 3) absence of constrictor spasm. Training focused on coordination of breath control, articulation, muscle relaxation, and proper handling and maintenance of the "duckbill" prosthesis. Speech intelligibility in 12 patients was evaluated following the completion of their speech rehabilitation program, using the CID Everyday Sentences. Each patient was videotaped; the tape then was presented to unbiased listeners who recorded the sentences. The median percentage of intelligibility for the 12 patients was 89.5%; only one patient had a median score less than 60%. The mean length of formal training for the group was only 3.2 hours (range 1 to 7 hours). The percentage of patients attaining speech and the quality of their speech intelligibility was found to be higher than with esophageal speech, which is both time consuming and often difficult to learn. TE puncture followed by proper fitting and training in voice prosthesis usage improves speech rehabilitation outcome for the laryngectomized patient.

Adult↗
PubMed1984

Pericardial-mechanical valved conduits in the management of right ventricular outflow tracts. Preliminary report.

Over the 3 year period from 1980 to 1982, mechanical prosthetic valves were implanted in the pulmonary pathway in seven patients. In two the procedure was a pulmonary valve replacement. In two it was an implantation of a pulmonary valve with transannular pericardial patching, and in three, complete pericardial (tube) conduits, which included mechanical valves, were constructed. There were neither perioperative nor late complications. Four patients were recatheterized. In three residual right ventricular hypertension was observed. In one of the three the cause of obstruction was not verified, but in the remaining two it was unrelated to the mechanical valve. No thromboembolic phenomena were observed.

Adolescent↗
PubMed1983

[Experimental studies of plasmacytoma. The idiotype as "marker"].

The idiotype is a product of malignant plasmacells and can be identified in a highly specific manner by antiidiotypic antisera. The idiotype is usefull as a tumor-specific marker in myelomas and has been worked with in different problems. The main methods used were: immunofluorescence, internal labeling of immunoglobulins with radioactive-labeled aminoacids, radio-immunobinding-inhibition assay. The results are as follows: 1. Idiotype bearing precursor-cells are detectable in the periphery of myeloma patients. But in our experimental approach we were not able to demonstrate, that these cells are in fact synthesizing the idiotype although the methode has been proved to be sensitive enough. 2. The idiotypic proportion of the total immunoglobulin-fraction (= M-component in the electrophorisis) in myelomasera ranges between 40 and 90%. This percentage remains in the order of 40% even in complete remission. 3. The idiotype as tumorspecific marker is only usefull as an early detector of relapse in patients with complete remission.

Adult↗
PubMed1983

Cardiac complications in vascular procedures: comparison of percutaneous angioplasty and surgery.

Percutaneous transluminal angioplasty (PTA) is currently recommended to high risk cardiac patients as a relatively safer procedure compared to reconstructive peripheral vascular surgery (RPVS). In order to evaluate this approach we studied the incidence of cardiac complications in 86 consecutive patients undergoing peripheral vascular procedures. 45 patients (Group I) underwent RPVS and 41 (Group II) PTA. The two groups were comparable regarding age, sex, the location of vascular lesions, the incidence of previous MI (Group I--40%, Group II--46%), and the incidence of angina pectoris (I--25%, II-29%). No special treatment or monitoring was used for patients with ischemic heart disease (IHD) in the PTA group. Successful revascularization was achieved in 36 (80%) of the surgical patients and 25 (61%) of the patients who underwent PTA. There were two anginal attacks, two MIs, and one cardiac death in group I compared to six anginas, three MIs, and one death in Group II. These differences are not statistically significant. It is concluded that PTA carries a definite risk of cardiac complications in patients with known IHD.

Aged↗