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Biomedical subjects

M Busch

Publications and source records attributed to M Busch.

54 records · Page 3Linked to original sources
PubMed1987

[Left ventricular function assessment using a floating catheter in dynamic and isometric (handgrip) stress in normal and heart infarct patients].

UNLABELLED: Left ventricular function was examined in a control group of 8 healthy men (average age 26 +/- 6.2 years) and was compared to 40 post-MI patients (average age 50 +/- 8.2 years, 39 men, one woman). It was measured using the floating-catheter technique under isometric exercise (50% of maximal voluntary contraction using both hands) and also under dynamic exercise (progressive supine bicycle-ergometry). In the control group, there was a significant increase in heart rate, arterial blood-pressure and the average PCP from rest to isometric exercises. PCP was noted to stay within its normal range (less than 20 mm Hg) under both modes of exercise. There was no significant difference comparing the effects of dynamic and isometric exercise (isometric: PCP 13.3 +/- 3.3 mm Hg; dynamic: PCP 11.8 +/- 3.6 mm Hg). In Group I (20 post-MI-patients showing ischemia during exercise-ECG) PCP stayed normal under isometric exercise (PCP 18.8 +/- 10.2 mm Hg). Under dynamic exercise, their PCP increased up to a pathological level (PCP 24.9 +/- 10.1 mm Hg, p less than 0.01). In Group II (20 post-MI-patients with lacking proof of ischemia during exercise-ECG) there was no significant difference between the increase in PCP under isometric vs dynamic exercise (isometric: PCP 18.7 +/- 13.4 mm Hg; dynamic: PCP 18.5 +/- 10.0 mm Hg). CONCLUSION: The results lead to the conclusion that isometric exercise alone (50% of maximal voluntary contraction using both hands, handgrip) can replace dynamic exercise in the diagnosis of LV malfunction in post-MI patients who do not show ischemia during exercise-ECG.

Adult↗
PubMed1986

[Dosage and possibilities for controlling thrombosis prevention with low-dose heparin].

The dosage of subcutaneous heparin examined (2 X 7500 international units per day) was shown to be unsatisfactory, as the average plasma heparin level in the patients was too low for over 9 h/day. This was a result of the fact that the interval between doses was too long and the therapy regimen thus not quite right. It was not possible to adjust the dose according to body height and weight because of lack of correlation with the plasma heparin levels. Control of the dose effect by the thrombin-clotting time test only showed a weak correlation. For high-risk patients in particular, an individually adjusted dosage is mandatory. Determination of the plasma heparin level can be helpful.

Dose-Response Relationship, Drug↗
PubMed1985

[Thin-layer densitometric determination of clotiazepam in tablets and blood plasma].

Quantitative determination of 7-ethyl-5-(2-chlorophenyl)-1-methyl-1,3-dihydro-2H-thieno[2,3-e]1, 4-diazepin-2-one (clotiazepam, Trecalmo) as pure substance and after extraction from tablets can be carried out by high performance thin-layer densitometry in absorbance at 243 nm. Detection limit was 10 ng/spot, and inaccuracy +/- 1.8% in the microgram range. For determination of clotiazepam in blood plasma, a more sensitive method was developed by fluorodensitometry above 460 nm after excitation at 313 nm. Analytical parameters are: detection limit 2.5 ng/ml, inaccuracy between 25 and 300 ng/ml +/- 5%, and imprecision at a concentration of 100 ng/ml +/- 5%. Plasma level determination up to 12 samples can be achieved in about 5 h. Thus, for determination of only a few samples, the HPTLC method is less time-consuming than the gas chromatographic assay.

Animals↗
PubMed1979

[Three dimensional optimization method for the interstitional afterloading therapy (author's transl)].

The authors present a new method for the interstitial therapy working with an Ir-192 source which is displaced step by step. After having been fed with the tumor parameters, the computer calculates for every stopping point the duration of stay of the source which provides a threedimensional optimization. The practical application of the method is discussed and the optimization procedure is compared with other similar methods.

Computers↗
PubMed1979

Multidetector endodosimetry probe with silicon-pn-junction-diodes for in-vivo-dosimetry.

In-vivo-dosimetry is necessary to prevent overdosage during radiation treatment techniques of great risk. New special dosemeter probes with up to five Si-pn-junction-diodes in a silicone tube were developed and tested for endodosimetry. They show high efficiency and good linearity of response, without dose-rate dependence. The steep increase of the sensitivity for low energies causes a phantom depth dependence of response. A low temperature dependence but a large anisotropy of response is found for the tested diodes. These multidetector probes proved to be sufficient for direct reading endodosimetric control of dose and dose-distribution during radiotherapy.

Brachytherapy↗
PubMed1978

[Measurement of the radiation load to bladder and rectum in gynecological brachytherapy with a mobile radiation source (author's transl)].

Measurement of the maximal radiation dose in bladder and rectum in intravaginal radiation therapy using a mobile source (afterloading technique) is only possible integrating with a multichannel dosimeter. For this purpose we apply a 5 mm plastic probe being equipped with five semiconductor dosimeter crystals; the latter are fixed within the probe at equidistances of 2 cm from each other. The dose maximum can be obtained by graphic interpolation using the five different values measured. The dosimeter employed is read immediately and permits observation of the doses delivered to the bladder and rectum during radiation therapy.

Female↗
PubMed1977

[The afterloading system of Essen for the intracavitary radiotherapy (author's transl)].

An afterloading system for the intracavitary radiotherapy is described which works with a unique radiation source of 10 Ci 192Ir moving in steps of 1 cm. The times during which the source stops can be determined at a control panel. By using an intermediate piece of 10 cm, a total course of the source of 20 cm can be obtained. The course of the source can be calculated individually by a computer program. This program even takes into consideration an additional deep therapy if the position of the deep therapy field in the target volume is known. This method allows to adapt the total isodoses very precisely to the course of the tolerance doses.

Female↗
PubMed1977

[Dosage in interstitial therapy with gamma emitters (author's transl)].

In this study a system of dose measurement and dosage in the interstitial is proposed. The radioactivity needed for the individual patient can be calculated by means of a simple formula. The author discu-ses rules for the distribution of the sources, clinical principles and the possibility of a combination with the external deep therapy.

Humans↗
PubMed1977

[Radiotherapy of lymphogranulomatosis--relations between radiomyelitis and oncogenic alteration of the spinal marrow (author's transl)].

The authors compare the results of two methods of the upper and lower system irradiation in case of Hodgkin's disease with respect to the spinal marrow. The frequency of radiomyelitis is opposed to the frequency of Hodgkin-specific alterations of the spinal marrow. 74 patients were submitted to telecobalt irradiations the dosage of which was below the tolerances known for the spinal marrow. Two of them presented a radiomyelitis and two a paraplegia of Hodgkin in the irradiated region. One paraplegia caused by the formation of a tumor developed in a region next to the irradiation field; certainly this region would have been affected by a higher dosed large-field irradiation of the spinal marrow. The application of the large-field methods in 61 patients did not cause any radiomyelitis in spite of doses which were higher than the tolerance doses for the spinal marrow of Franke. Hodgkin- specific infiltrations of the spinal canal were also not observed. The large-field method can also be recommended because it seems to offer a larger therapeutic field between the risks of spinal Hodgkin manifestations and radiomyelitis.

Adult↗
PubMed1975

[The dose-volume factor in radiotherapy. Significance of the focal or tumor volume for the evaluation of radiotherapeutic effect].

The absorbed energy dose, in dependence on the irradiated tissue volume or tumor volume (dose-volume-relations) has great significance for the valuation of radiation injuries and of the prognosis of the disease. The present paper includes an analysis, formal demonstrations and interpretation of these relations. Clinical observations and radiobiological experiments in literature were the basis of the present investigation. The assessment is kept simple, the models derived from it interprete well the clinical findings. Through these models, radiobiological findings and clinical experimental principles are connected. This results in a clear conception of the future development of irradiation planning, and the application technique of radiation. The range of validity of the cited models includes the treated volumes usual in radiotherapy. An extrapolation to the cellulary area or to the whole body may only be made with great reservations.

Humans↗
PubMedDate not supplied

Identification of HIV-infected transfusion recipients: the utility of crossreferencing previous donor records with AIDS case reports.

An expanded "look-back" program has been developed, in which patients who may have been exposed to HIV through blood transfusion were identified via three triggers: the blood that they received was donated by persons who 1) have subsequently been reported to local health departments as meeting the diagnostic criteria for AIDS, 2) have donated since the introduction of anti-HIV screening and tested positive, or 3) have been found to be infected during investigation of reported transfusion-associated HIV infections. In comparing triggers, cross-referencing the list of patients reported to have AIDS (AIDS case list) proved to be the most efficient approach for identifying HIV-infected donors and transfusion recipients. Of the 7973 AIDS patients reported in eight Northern California counties as of December 1988, 316 (4.0%) were determined to have donated at Irwin Memorial Blood Centers between 1977 and 1985. Despite the logarithmic increase in reported cases of AIDS in the San Francisco Bay area over the last 5 years, the rate of detection of previous donors from AIDS case lists remained between 3.3 and 5.4 percent. These persons accounted for 69 percent of the identified infected donors, and their identification led to notification of 60 percent of potentially exposed recipients and 51 percent of known infected recipients. The crossreferencing of AIDS case listings with blood bank records was equally efficient for regions with low and high AIDS prevalence. National adoption of AIDS case list crossreferencing is recommended as an effective means of identifying previously unidentified infected recipients in an effort to limit the secondary spread of HIV infection.

Acquired Immunodeficiency Syndrome↗
PubMedDate not supplied

Increased detection of hepatitis C virus (HCV)-infected blood donors by a multiple-antigen HCV enzyme immunoassay.

A new, multiple-antigen enzyme immunoassay (EIA-2) for hepatitis C virus (HCV) antibodies was evaluated in parallel with the previously available c100-3 HCV EIA (EIA-1) in 14,068 volunteer blood donors as well as in 25 cases of transfusion-associated hepatitis C for which recipient and donor samples were available. When compared to EIA-1, the EIA-2 was more sensitive in detecting HCV-infected blood donors. The EIA-2 detected an additional 1 in 1000 EIA-1-negative, surrogate marker-negative donors who were infected with HCV as demonstrated by polymerase chain reaction (PCR). The specificity of the EIA-2 was comparable to that of the EIA-1, but the two tests appear to detect different populations of false-positive donors. Recombinant immunoblot assay-indeterminate donors were detected five times more frequently by the EIA-2; PCR demonstrated that 21 percent of these donors were infected with HCV. The greater sensitivity of EIA-2 was also found in 25 transfusion recipients with non-A, non-B hepatitis; however, in 16 percent of these cases of posttransfusion HCV infection, the EIA-2 failed to detect an HCV-seropositive donor. These data indicate that EIA-2 testing will significantly reduce, but probably not eliminate, the risk of transfusion-associated HCV infection; we estimate this residual per-unit risk to be 1 in 2000 to 1 in 6000 units transfused. On a national level, it is projected that the replacement of the anti-HCV EIA-1 with the EIA-2 will initially prevent up to 40 additional cases of transfusion-associated hepatitis C per day.

Blood Donors↗