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Biomedical subjects

F Lorenz

Publications and source records attributed to F Lorenz.

At least 19 recordsLinked to original sources
PubMed2002

Regression of left ventricular hypertrophy in hemodialysis patients is possible.

Regression of left ventricular hypertrophy in hemodialysis patients is possible. Left ventricular hypertrophy represents the major risk factor for cardiac morbidity and mortality. Therefore, their regression is mandatory. Since the causes of uremia-associated left ventricular hypertrophy are multifactorial, various therapeutic options can be considered: optimal control of arterial hypertension and volume status, optimal correction of metabolic acidosis, best possible correction of hypoalbuminemia and severe secondary hyperparathyroidism, modern pharmacotherapeutic strategy for the treatment of heart failure (use of angiotensin-converting enzyme inhibitors in combination with angiotensin II receptor blockers and beta-blockers) and total correction of renal anemia. Following the proposed therapeutic strategies we could, by using echocardiography, distinguish in 100 hemodialysis patients the following 3 groups (on the average after 1.5 years): 36 patients with initially normal left ventricular mass index (LVMI (g/m2), F < 110; M < 130) maintained normal (group 1); in 31 patients with moderately increased LVMI full regression resulted (group 2); 33 patients with severely increased LVMI (group 3) had to be further divided into 2 sub-groups: 22 patients with significant improvement of LVMI, 11 patients with no, regression. For the first time we were able to show that it is possible to maintain initially normal LVMI during long-term treatment and to achieve complete regression and significant improvement of LVMI in our patients. However, since LVMI requires a long time to develop, a similarly long time must be estimated for its regression. However, 11 patients remained therapeutically resistant. In this group, severe heart diseases were often combined and highly prevalent, including ischemic heart and valve diseases and end-stage dilatative cardiomyopathy. These patients had to be transferred to cardiac surgery. Anemia is considered to be one of the most important factors for the development of left ventricular hypertrophy. Therefore, total correction of renal anemia has to be strongly recommended in addition to other measures of our therapeutic strategy to maintain full or significant regression of left ventricular hypertrophy.

Adolescent↗
PubMed2001

Open wedge tibial osteotomy by hemicallotasis for medial compartment osteoarthritis.

Early clinical results were evaluated for 22 adult patients who had undergone an open wedge tibial osteotomy by hemicallotasis (HCO) due to medial compartment osteoarthritis. The mean age at the time of the index operation was 56 (range 33-66) years. The mean duration of follow up was 16 (range 9-23) months. The median hip-knee-ankle angle (HKA) was 169 (range 162-186) deg preoperatively and 182 (range 175-191) deg at follow up. We did not observe any early collapse of the new bone wedge. The median time to fixation was 79 (range 63-125) days. Complications included two pintract infections, and two hematomas were revised. Two patients felt pain during the phase of distraction, but the procedure could be continued after a short break. We evaluated the clinical results on the HSS, Lysholm, and Tegner activity scores. At the latest follow up examination, all of the scores had improved. Our findings demonstrate that HCO requires an exact correction, is a simple technique, and appears to reduce the chance of nerve and vascular damage.

Humans↗
PubMed1999

[Methods of mobilizing hematopoietic cells, their collection using cell separation, purging--processing of pathologic cells and enrichment with CD 34+ cells--negative and positive selection].

Autological transplantation of bone marrow as well as hematopoietic and precursor cells obtained from peripheral blood with the use of cell apheresis is a therapy applied in the treatment of hematological diseases and solid tumours. The mobilization of hematopoietic cells is performed by applying cytostatic drugs and/or recombinant growth factors (G-CSF, GM-CSF). The collection of CD 34+ cells is performed by using cell separators. An important role in the transplantation procedure is played by purging techniques of transplantation material from residual neoplastic cells (negative selection) or isolation of hematopoietic cells (positive selection). The considerable progress in this field is connected with the implementation of Immunoadsorbtive or magnetic methods as well as those of molecular biology. The improvement of the procedure of hematopoietic cells transplantation and its efficacy is caused by the stimulation of the hematopoiesis by using the combination of cytokines (G-CSF, GM-CSF, IL-3, SCF) and purging of the hematopoietic cells obtained from the cellular apheresis.

Antigens, CD34↗
PubMed1999

[Methods for freezing, thawing and viability estimation of hemopoietic stem cells].

Freezing and thawing of hemopoietic stem cells (CD34+) are indispensable stages between their collection from peripheral blood or bone marrow and transfusion to the patient who has previously undergone myeloablative chemotherapy. At present there are two methods of the cells freezing: non-controlled--placing CD34+ cells directly in the final temperature and rate-controlled--gradual cooling them at programmed speed. Non-controlled freezing leads to the considerable loss of cells viability (up to 50%), but it doesn't require the expensive equipment used for rate-controlled freezing (viability loss up to 10%). In order to reduce the loss resulting from intra-cellular crystallization of water the haemopoietic cells are mixed with one of the cryopreservative substances: dimethylsulphoxide-DMSO, hydro-xyethylstarch-HES, polyvinylpyrrolidone-PVP or glycerol. The most important moment of freezing procedure is the phase transition of water. The adequate shape of the cooling curve leads to a considerable reduction of the loss of the cells viability. Further cooling is the most effective when it takes place at max. speed of 5 degrees C/min. The storage of the frozen cells is the best in very low temperatures (-170-180 degrees C-vapour phase of liquid nitrogen), but mechanical freezers (-80 degrees C) are used, too. The thawing procedure should be very fast (up to 90 degrees C/min.) and the defrosted cells must be immediately transfused to the patient because of very high toxicity of cryopreservative agents to non-frozen cells. The cells viability estimation is carried out with trypan blue or cytofluorometrically after incubation with propidine iodide.

Cell Count↗
PubMed1999

[Autotransplantation for solid tumors].

Over the last three decades, there have been a number of advances made in the treatment of haematological malignancies including an increasingly defined role in curative therapy programmes for high dose chemotherapy (HDC) with stem cell support. This has provided an impetus for similar approaches to be tested in solid tumours. Drug resistance is one of the most important reasons for treatment failure in these diseases, and therefore attempting to overcome it with HDC is an obvious strategy to investigate. This rationale is supported by laboratory data demonstrating that dose correlates with number of cells killed, and that increasing drug doses by 5-10 fold can overcome resistance. Clear evidence of a dose-response effect in patients is provided by numerous clinical trials of chemotherapy in solid tumours. A large number of studies have investigated HDC in solid tumours, particularly in those malignancies which demonstrate initial chemo-sensitivity, but later relapse. Except for breast cancer, for other solid tumours there are no randomised trials defining the role of HDC. Many of the trials are small pilot studies in heavily pretreated patients with large volume disease and therefore any conclusions must be guarded.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1996

Gender differences in health: evidence from the Czech Republic.

Gender differences in health have been linked to gender stratification in the United States. Women's relation to production, paid and unpaid work, and their experience of this gender inequality disadvantage their self-rated health compared to men. Men's consumption or health lifestyles disfavors their comparative health. This formulation is tested in the Czech Republic with a sample of matched wives and husbands (N = 577 households). This extends previous research in the United States on gender differences in health in two ways: into post-communist Europe and by comparing paired wives and husbands. Respondents completed questionnaires in 1994 on their health and well-being, jobs and finances, non-economic life events, marriage, psychological states, opinions about the changes in the Czech Republic, and socioeconomic background. Wives and husbands filled out separate questionnaires. The relation to production (both the objective relation and its subjective experience) did not impair wives' self-reported health any more than that of their husbands, and husbands' consumption or health lifestyles did not put them at a health disadvantage. Interpretations of these findings rest on both the extension of the study into post-communist Europe and by comparing matched wives and husbands.

Adult↗
PubMed1995

Human herpesvirus type 7 in blood donors: detection by the polymerase chain reaction.

In order to evaluate the prevalence of human herpesvirus type 7 (HHV-7) in adult blood donors oral lavage fluid, buffy coat, and urine samples from 112 persons were examined by the polymerase chain reaction (PCR) at one time point. In addition, 11 donors were studied longitudinally over 11 weeks. When the results of the initial and the longitudinal study were combined HHV-7 DNA was found in samples from 109 of 112 (97.3%) adult blood donors. On the basis of different sensitivity levels of the first and the nested PCR differences were detected in the viral DNA load in the samples. It was found that lavage fluid regularly carried significantly higher DNA concentrations than buffy coat. Out of 112 donors, 102 (91.1%) and 8 (7.1%) were positive in the first, less sensitive PCR in lavage fluid and buffy coat, respectively (P < .0001). After nested PCR, 107 (95.5%) and 74 (66.1%) were positive in lavage fluid and buffy coat, respectively (P < .0001). Urine samples were found positive only sporadically. The longitudinal study showed that the oral lavage fluid of most of the donors consistently carried HHV-7 over up to 53 weeks, whereas buffy coat samples were positive less often. In conclusion, HHV-7 is found frequently in adult blood donors in the oral lavage fluid and buffy coat, which are, therefore, potential sources of HHV-7 transmission.

Adult↗
PubMed1991

[Detection and characterization of Salmonella strains from laughing gulls (Larus ridibundus)].

25 and 17 Salmonella strains could be isolated from 429 and 423 blackheaded gulls (Larus ridibundus), respectively, during two years of examination. S. typhimurium was the most frequent serovar. All strains of S. typhimurium belonged to the biochemovar c (inosite and rhamnose negative), nearly a third of isolates caused a mannose-sensitive hemagglutination of guinea pig erythrocytes. This result is in contradiction to the literature. Furthermore the phagovars, the plasmid profiles and the resistance against chemotherapeutics were tested. The Salmonella carriage by gulls presumably reflects the contamination of the environment.

Animals↗