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Biomedical subjects

M Langer

Publications and source records attributed to M Langer.

At least 343 records · Page 19Linked to original sources

The prone position in ARDS patients. A clinical study.

The gas exchange and hemodynamics were evaluated before, during, and after a two-hour period of prone position in 13 moderate-severe ARDS patients. Lung computerized tomography was obtained in both the supine and prone positions in two of these patients. Average arterial oxygenation improved after prone positioning (p less than 0.01). A PaO2 improvement of at least 10 mm Hg after 30 minutes of prone position was used as a criterion to discriminate between responders and nonresponders to the postural change. Eight patients met the "responders" group criterion, and in the five nonresponder patients, the PaO2 did not change significantly throughout the study. Computerized tomograms in the prone position showed disappearance of posterobasal densities and appearance of new densities in the anterior regions, in both patients studied. One of these was a responder, the other a nonresponder. A brief test period in prone position is indicated in ARDS patients to identify those who may benefit from this postural treatment. The definite mechanism of the arterial oxygenation improvement observed remains to be clarified.

Adult↗

[Ultrasound findings in patients with AIDS].

The ultrasonographic findings of 43 patients with AIDS and ARC were analyzed. In 63% an enlarged liver, in 66% an enlarged spleen, partially with focal lesions, and in 21% enlarged abdominal lymph nodes were diagnosed. The typical parenchymal lesions of the kidney (focal segmental glomerulosclerosis) were not observed. Abdominal ultrasound is the first diagnostic procedure to perform in patients with AIDS and ARC with the suspicion of abdominal pathology. With additional thin needle puncture of the lesions a histological verification of the pathologic findings is possible.

AIDS-Related Complex↗

[Digital radiographic image enhancement in bone diagnosis--initial clinical results].

34 patients with skeletal alterations mostly in the periphery were investigated by digital image intensifier radiography (DIIR). A high resolution image-intensifier system (1024 x 1024 matrix, 40 cm, 28 cm, 14 cm image intensifier, maximal spatial resolution: 3.6 lp/mm) was available. The image quality was diagnostic sufficient in 76% using DIIR. A good or very good image quality of fine-structures was obtained only in 41%. The quality deficits in comparison to conventional radiograms were particularly obvious in investigation of the phalangeals. Logarithmic amplification and software upgrading lead after these first clinical investigations to a better image quality.

Adult↗

[Comparative clinical studies of myocardial blood flow in coronary heart disease with two nifedipine preparations].

Clinical, ergometric and scintigraphic examinations were performed before and after oral administration of a commercially available nifedipine preparation used as a standard (reference preparation; dosage: 3 x 10 mg/d) in 21 patients with angiographically verified coronary artery disease. In an open comparison study the same parameters were investigated after a 4 week course of a different nifedipine preparation as a test preparation (Corotrend; dosage: 3 x 10 mg/d). The study was performed in order to determine whether there were quantitative differences in myocardial microperfusion when different galenical preparations of nifedipine were used. There were no statistically significant differences between the two nifedipine preparations in the test parameters recorded. Both substances were associated with highly significant increases in microperfusion as compared to findings in the washout phase. Clinical effects on incidence of chest pain and on reductions in blood pressure were comparable. Patients demonstrated slightly better exercise tolerance with the reference agent, and computerised impulse-rate analysis of the tomoscintigrams demonstrated somewhat better microperfusion with this drug, though the differences between the two agents did not attain statistical significance. As the result of this analysis the two drugs would appear to be equivalent in clinical potency.

Aged↗

Microperfusion in coronary artery disease under treatment with the calcium antagonist gallopamil.

The calcium antagonistic principle, i.e. the inhibition of calcium influx into the heart muscle cell and smooth muscle cell, in this particular case gallopamil as an example of a drug with this principle of action, can certainly be regarded as one of the most important concepts in modern coronary therapy. On account of the increase of myocardial perfusion, which is ascribed to this calcium antagonist, gallopamil may be administered as an adjunct to postoperative therapy. It is even a drug alternative to bypass grafting. Previous investigations of the ST segment and subjective ischemic parameters have not always shown coherent findings. The purpose of this study was to objectify clinical improvement after therapy with gallopamil (Procorum) by means of reliable methods and reproducible measurements. Myocardial perfusion was analysed in 31 patients by longitudinal tomoscintigraphy before and after therapy with 2 x 2 mg gallopamil intravenously and 6 weeks at 3 x 50 mg/d orally followed by placebo control. The computerized circumferential mapping of impulse rates showed a significant increase of impulse density in ischemic segments after both intravenous and oral therapy with gallopamil.

Administration, Oral↗

Use of nuclear magnetic resonance imaging to show regression of hypertrophy with ramipril treatment.

Thirty-two patients with arterial hypertension (diastolic blood pressure greater than 95 mm Hg) were treated with ramipril for 3 months. The aim of the study was to achieve an effective decrease in blood pressure and demonstrate reliably and reproducibly that regression of left ventricular hypertrophy takes place with ramipril treatment. Nuclear magnetic resonance images and echocardiographic measurements of the left ventricle were therefore made before treatment started, 4 hours after the first dose, 14 days after the start of treatment and after 3 months of treatment. The thickness of the septum decreased from 19.57 to 15.20 mm on magnetic resonance scans and from 18.78 to 14.57 mm on echocardiograms. The values were reproduced 3 times at the same measuring point and means were calculated. The septum and posterior wall of the left ventricle were also measured at 3 different points. With negligible scatter, the values obtained were reproducible and the differences were highly significant (p = 0.001). A parallel decrease in blood pressure to levels 15% below baseline was also observed. The therapeutic aim of achieving diastolic blood pressure levels of less than or equal to 90 mm Hg was achieved in all patients. In addition to reducing the blood pressure significantly, the angiotensin converting enzyme inhibitor ramipril caused a significant regression of pathologic left ventricular hypertrophy, which was demonstrated clearly using magnetic resonance imaging and echocardiography.

Angiotensin-Converting Enzyme Inhibitors↗

Early onset pneumonia: a multicenter study in intensive care units.

A prospective multicenter study concerning the incidence, onset time, risk factors and mortality of pneumonia was carried out by the Intensive Care Units Collaborative Group for Infection Control in Lombardy, Northern Italy. Out of 1304 patients admitted over 3 months in 16 intensive care units (ICUs), 441 met the criteria for the protocol (no previous pulmonary infection or irreversible terminal illness, ICU stay greater than 48 h). The incidence of acquired pneumonia was 21.3% (94/441), with 54.2% of cases diagnosed within 4 days of admission (early onset pneumonia). Impairment of airway reflexes on admission and more than 24 h respiratory assistance were shown as significant risk factors (RR) for early onset pneumonia (respectively RR = 12.4, with 95% confidence interval (CI) = 5.3-28.9 and RR = 3.3, with 95% CI = 1.8-5.9). A suggested pathogenetic mechanism is aspiration of oropharyngeal contents at the onset of acute illness, due to depression of protective reflexes with delayed clearance of bacterial contamination. No protection was offered by routinely applied prophylactic antibiotic therapy.

Anti-Bacterial Agents↗

HLA-class II antigens on human hematopoietic progenitors.

A panel of alloindifferent monoclonal antibodies (MAB's) was used in complement-dependent lysis to characterize human myeloid, erythroid and multipotential progenitors (CFU-GM, BFU-E, CFU-GEMM) for their expression of MHC class II HLA-DR, -DP, and -DQ products. 7-16 donors were tested in each system. MAB Tü 34, detecting DR products, caused reduction of CFU-GM by a mean of 89%, whereas BFU-E and CFU-GEMM were reduced by 67% and 66% respectively. 35% of CFU-GM, 27% of BFU-E and 32% of CFU-GEMM were lysed by MAB B7/21, recognizing HLA-DP determinants, while Tü 22, binding HLA-DQ antigens, lysed 32% only of CFU-GM and did not lyse the other progenitors. Employing the "broad" MAB Tü 39, which binds at least DR and DP, inhibition of colony formation by CFU-GM was generally greater than that caused by Tü 34 alone or even by combinations of Tü 34, Tü 22, and B7/21. This suggests that there may be a subset of DR-, DP-, DQ- hematopoietic progenitors, which nonetheless bind MAB Tü 39, previously proposed as a candidate for the recognition of novel class II antigens.

Antibodies, Monoclonal↗

Optimization of beam weights under dose-volume restrictions.

A basic problem in treatment planning is the selection of weights for a set of beams which will yield the largest tumor dose under constraints limiting the doses received in specified fractions of different normal tissue structures. This report describes a method for formulating and solving this optimization problem as a combinatorial linear program. An illustration is provided by a problem in planning treatment of a thoracic tumor, in which no more than 1/2 or 2/3 of the lung is permitted to receive greater than 20 Gy and no part of the spinal cord allowed to receive greater than 45 Gy. The optimization technique was applied to this example to determine how the maximum tumor dose is affected by changes in the normal tissue constraints and the addition of a tumor dose homogeneity restriction. The linear programming technique yielded a rigorous and efficient determination of the beam weights for the thoracic plan considered. An exhaustive specification of all the underlying linear programs allows problems of moderate dimensions to be solved, while developments in mathematical programming and computer processing suggest approaches to problems of greater complexity.

Humans↗

[Management of couples following prenatal diagnosis of fetal abnormalities].

Methods of prenatal diagnosis have changed the time when, and the circumstances in which parents find out that their child has a malformation. The different phases of counseling of a couple who had experienced recurring fetal cystic hygroma in two consecutive pregnancies are described. In several consultations the authors tried to respond to the specific psychologic reactions to the diagnosis of fetal malformation and to deal with them. Typical sequelae such as shock, grief, and the formation of subjective theories are discussed, as well as the time needed for counseling and interaction with clinic staff. Guidelines for client-centered, interdisciplinary and preventive counseling are proposed.

Abortion, Eugenic↗