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Biomedical subjects

R Fink

Publications and source records attributed to R Fink.

At least 109 records · Page 6Linked to original sources
PubMed1978

Modified K-channel gating by exhaustion and the block by internally applied TEA+ and 4-aminopyridine in muscle.

Voltage clamp experiments on frog sartorius muscle fibres suggest that the large increase in resting potassium conductance during metabolic exhaustion is due to a change in the gating of activated potassium channels to a permanently open state. gK in exhausted fibres is less sensitive to externally applied blockers as Zn2+ and 4-aminopyridine (4-AP) while TEA+, Rb+ and Ba2+ act similarly, both in normal and exhausted fibres. In addition, injection experiments provide evidence that TEA+ and 4-AP applied internally to normal fibres effectively block potassium outward current, whereas in exhausted fibres the block seems to be smaller. These results suggest modifications in the structure of the potassium channels during metabolic exhaustion.

Animals↗
PubMed1978

An approach to cost analysis of clinical laboratory services.

The authors have developed a system that provides information about costs related to specific laboratory tests. These costs are derived from: (1) labor and material actually used for specific tests; (2) allocation of costs for labor and material shared by several different tests; (3) allocation of supervisory and management costs. The "cost" of a specific procedure is a theoretical construct that is significantly affected by the method chosen for allocation. We know of no cost-analysis system generally accepted by all clinical laboratories. Since third-party payers may base future reimbursement on costs rather than charges, accurate systems for clinical laboratory cost analysis may have some practical value.

Clinical Laboratory Techniques↗
PubMed1978

[The appearance of immature cell leukemias after radiologic and cytostatic intensive therapy of Hodgkin's lymphoma].

Among 106 patients with Hodgkin's lymphoma in stage IIIB and IVB treated from September 1969 to June 1977 by a working team for hematology and oncology at the clinic and outpatients clinic of the Medical School of Erfurt, there were two cases (=1.9%) showing a final transition to leukaemia with immature cells. A third neoplasia which had developed in a former field of irradiation was additionally observed in one patient. The various possibilities arising from an oncologic effect of ionizing rays and those substances having a cytostatic effect are discussed. After frequent reports on the occurrence of secondary tumours following intensive radiological and cytostatic therapy of advanced Hodgkin's lymphoma the enhanced risk of a secondary tumour being induced by this combined therapy cannot be excluded. Various conclusions are drawn from that by the authors.

Cyclophosphamide↗
PubMed1977

[Stem-cell leukoses in the adult age--a clinical study].

The cytochemical differentiation of 86 stem cell leucoses of adults resulted with 74% of the cases in a clear prevalence of PAS-negative forms at this age. PAS-positive leucoses were observed only in 11%. The survival time of the patients revealed a clear dependence of the degree of the remission achieved. Also for the cases of PAS-negative leucoses, which achieved a complete remission, it was not worse than the survival time of acute lymphoplastic leucoses. However, the remission coefficient of the PAS-negative leucoses was essentially below the value of lymphoblastic forms. Multiple cytostatic combinations reached the best remission rates. Above all the combination of ribidomycin, cytosine arabinosid (Alexan), 6-mercaptopurine (Mercaleukin), prednisolone and vincristine (Oncovin), called RAMPO-scheme by the authors, seemed to give much success according to the results of this study. The number of complete and good partial remissions was calculated with 62% for the ViDaP-scheme, with 51% for the COAP-scheme. For all cases of treatment the coefficient of remission was 54%.

Adolescent↗
PubMed1977

Oral health status in relation to socioeconomic and ethnic characteristics of urban adults in the U.S.A.

Nearly 1,300 adult members of a prepaid medical group plan in New York City were screened through automated multiphasic health testing in a series of test stations including a dental station, during 1971-1973. Oral status indicators were developed including a number of missing teeth, scores to measure levels of gingival and periodontal disease, Simplified Oral Hygiene Index scores, and ratios of decayed teeth. Ratios of filled teeth were calculated to measure levels of restorative care. The present paper examines the interrelationships of economic status, education and ethnic origin with each of the above oral status measures. It was found that variations in ratios of decayed and of filled teeth were primarily due to economic status while variations in a number of missing teeth, oral hygiene levels and levels of gingival and periodontal diseases were primarily due to screenees' educational level. Ethnic group differences could be explained in part by differences among these groups in economic and and educational levels. There were no consistent ethnic patterns, however, and while some differences could be explained by controlling for education and economic status, others persisted.

Adult↗
PubMed1977

Serum enzymes and isoenzymes after surgery.

Serum creatine kinase, aspartate transaminase, and hydroxybutyrate dehydrogenase activities were abnormal in 76, 50, and 28% respectively of 50 patients studied within 26 hours of surgery. No patient showed clinical evidence of myocardial infarction. Creatine kinase MB isoenzyme elevation, and lactate dehydrogenase LD1 activity greater than LD2 (LD) greater than LD2) were infrequent (6 and 10% respectively). No patient showed the combination of transient MB isoenzyme elevation and LD1 greater than LD2, although their rare association without infarction after surgery is to be anticipated.

Adolescent↗
PubMed1976

[Ways and possibilities in the diagnosis of leukemic diseases].

Malign diseases and thus also leucoses are pathogenetically as well as therapeutically an up to now unsolved problem. Since according to the modern standard of our knowledge a chance of healing at best is to be found in the recognition of the pre-stages and the early stages, therefore, intensive diagnostic efforts are necessary. In these cases the usual hematological methods of examination alone cannot help on. Without doubt, the cytochemical and autoradiographic investigation methods are an essential enrichment in the diagnostics. Hopeful perspectives in the early recognition of leucaemic diseases, however, indicate themselves only by new realizations in the field of cytogenetics and by further research of the metabolic function and the molecular biology of the tumour cells.

Acid Phosphatase↗
PubMed1976

A worksheet summary system for clinical laboratory management.

This article describes a simple method for summarizing total activity from the worksheets used at each workstation in a clinical laboratory. Monthly reports display day-to-day trends in total workload, as well as changes in the ratio between charged and total tests. Cumulative summaries of the monthly reports display month-to-month trends of total workload, as well as the ratio between charged and total tests. These reports also provide: (1) a simple method to calculate "lost revenue" (difference between total "chargeable" work and credited revenue); (2) more rapid and more uniform calculation of CAP workload units. In the author's laboratory, time required to maintain this data base and calculate CAP workload units has been less than the time previously required for calculation of CAP workload units alone.

Cost-Benefit Analysis↗
PubMed1976

An evaluation of the membrane constants and the potassium conductance in metabolically exhausted muscle fibres.

1. The membrane characteristics of metabolically poisoned and mechanically exhausted frog skeletal muscle fibres were investigated with intracellular micro-electrodes. 2. When cyanide plus iodoacetate were applied as metabolic poisons twitch tension declined towards zero after 150-300 stimuli (0-3 Hz; temperature = 0 degrees C). At the beginning of stimulation the mean resting potenial fell from -75 to -69 mV; it rose subsequently to -83 mV. The membrane resistance decreased during this stimulation period along a sigmoid time course to 4-6% of the original value. 3. In completely exhausted fibres the following membrane constants were estimated (23 degrees C): length constant, 0-31 mm; input resistance, 31 komega; membrane resistance, 58 omega.cm2. These values were calculated under the assumption of a constant internal resistivity of 170 omega. cm. The Q10 values of these constants were similar to those in normal fibres. Afew experiments revealed that the membrane capacity remained roughly constant under these conditions. 4. The current-voltage relation of exhausted fibres was approximately linear in the range between -60 and -100 mV. At less negative potentials the conductance increased slightly while at more negative potentials it decreased. The latter, in particular, became more evident when the imput current was converted into membrane current density by applying Cole's theorem. 5TEA+ and Rb+ in the external solution increased the membrane resistance of exhausted fibres by more than one order of magnitude. The major part of the membrane conductance induced by exhaustion, however, could not be blocked by these ions or Zn2+. 6. Chloride-free test solutions were used to measure the relative contributions of potassium and chloride ions to the membrane conductance. The relation GK:GC1 changed from 2:3 in normal fibres to 5:1 in exhausted ones. In absolute terms GK rose from ca. 130 to 14,300 mumho/cm2 and GC1 from ca. 200 to 2900 mumho/cm2. The discrimination between K+ and Na+ by the resting membrane in exhausted fibres was probably equal to or even higher than that under normal conditions. 7. In normal fibres the input resistance decreased by up to 20% after the external application of 1-2 mM caffeine, which is known to release calcium ions from internal stores. The elevation in internal Ca2+ by direct injection caused a small and, as a rule, irreversible decrease in input resistance which was probably partly due to local damage to the surface membrane. 8. It is concluded that in metabolically exhausted muscle fibres the surface and tubular membranes are still intact and that the observed decrease in membrane resistance is mainly due to an increase in potassium conductance. In addition, the results indicate that the gating mechanism of the potassium channels (presumably those with the characteristics of the slow component) is affected when energy reserves diminish.

Animals↗
PubMed1976

[Problems in the treatment of stem cell leukemias in aged patients].

Stem-cell leukemias will reveal a second peak of frequency at old age. The cytochemical differentiation in 26 patients of old age revealed a preponderance of myeloblastic forms. Moreover, a slight accumulation of monocytic and myelo-monocytic types could also be observed. In spite of this apparently unfavourable cytochemical differentiation the relatively good capability of myeloblastic leukemias of responding to cytostatic treatment was surprising. However, no cytostatic maximum programmes should be chosen in view of the low regenerating ability of the bone marrow in old patients.

Aged↗
PubMed1975

Comparisons of poverty and nonpoverty groups on dental status, needs, and practices.

Poverty and nonpoverty adults have been screened in a program of Multiphasic Health Testing in which dental examinations were provided and in which information on dental care behavior was obtained through a health inventory using a video-terminal for recording replies. Findings of the dental examination indicate that, whatever measure of oral health was used, oral health of the poverty group was poorer than that of the nonpoverty group. The poverty group, for example, had more dental problems, and the problems they had were more severe. They also had lower levels of oral hygiene and less restorative treatment. The poverty group also was more likely to be edentulous, and to have higher levels of untreated decay and periodontal diseases. They had more missing teeth, and fewer restored teeth. Nearly all poverty-nonpoverty differences persisted when the data were controlled for age and sex. Information from the health inventory indicates that the poverty group is less likely than those in the nonpoverty group to seek dental care in general, and also specifically for rreventive dental services. Even among the nonpoverty group, however, one third stated that they never sought dental care for "cleanings or checkups." Daily toothbrushing, on the other hand, was generally reported by both poverty-status groups. Consistent relations were found between oral health practices and oral health in both poverty and nonpoverty groups...

Adolescent↗
PubMed1975

Computerization of the surgical intensive care unit: improvement of patient care via education.

For the past 18 months we have been evaluating and developing a computerized patient-monitoring system in our surgical intensive care unit. Despite the enormous potential for use of such systems, we have been impressed with its underutilization and its failure to yield objective improvement in patient care at our institution and many others. The output of the system was ignored because the decision maker was unable or unwilling to integrate the more sophisticated data presented to him. The computer was relegated to the position of "redundant secretary". In an attempt to reverse this situation, we have developed a multilevel, multigoal educational system employing the computer. We have implemented brief educational programs for use by all unit personnel to explain deviant monitored variables. Given a physiologic subsystem and a particular variable, personnel can: (1) inquire whether or not the variable is deviant; (2) obtain a list of probable causes for the deviation; (3) obtain an explanation of the pathophysiology of particular deviants as well as instruction on how to identify a most probable cause; and (4) inquire how to correct specific deviants. When we monitored the system utilization after implementation of the educational programs, we found all of the system had improved utilization. As a result we have a better educated staff who communicate more effectively, deal with more sophisticated information, and make better decisions with resultant improved patient care. Additionally, the staff is eager to help improve the system. We believe the full potential of such systems can be obtained only through education.

California↗