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Biomedical subjects

F Kavaler

Publications and source records attributed to F Kavaler.

At least 19 recordsLinked to original sources
PubMed1997

America's first medical malpractice crisis, 1835-1865.

Prior to the early 1800's, medical malpractice was almost unknown in the United States. However, a large number of malpractice law suits inundated the courts between 1835 and 1865. About 70 to 90 percent of the litigation involved fractures and dislocations with imperfect results or deformities such as shortened or crooked limbs. Lawyers alleged that the physicians did not provide due proper care, skill and diligence despite the fact that the better surgeons tried to save limbs rather than follow the common practice of amputation, especially for compound fractures. While a number of texts dealt with medical jurisprudence, it was not until 1860 that a text on the subject intensively delved into the issue of medical malpractice. Coincidentally, the attitudes and behaviors of patients, lawyers, physicians and judges during the first medical malpractice crisis were surprisingly similar to those currently held.

Attitude of Health Personnel↗
PubMed1991

Cadmium block of isometric contractions of isolated bullfrog atrial cells.

We studied the effect of cadmium, verapamil, and quinacrine on the force of contraction (Fp) of isolated, single, field-stimulated bullfrog atrial cells. All agents were applied or removed rapidly (t1/2 approximately 15 ms) to minimize intracellular concentration changes other than intracellular calcium concentration. Two components of twitch force were observed, one blocked by micromolar Cd2+ and the other by millimolar Cd2+. The two contributed about equally to the activation of the twitch. The "cadmium-sensitive" portion of force (that affected by [Cd] less than or equal to 100 microM) had a K1/2 approximately 1 microM, was identical in magnitude to, and not additive with, a "verapamil-sensitive" (10 microM) component of force, was most strongly affected by 50-ms pulses of Cd2+ when they were applied in the mechanical latent period, and was potentiated by catecholamines. The cadmium-insensitive portion of force was abolished by the removal of extracellular calcium and was greatly potentiated by quinacrine (3 or 10 microM), a blocker of Na-Ca exchange. The results are consistent with the idea that activating calcium enters the cell via both an inactivating cadmium-sensitive L-type channel and a noninactivating cadmium-insensitive mechanism that is not Na-Ca exchange and leaves the cell via Na-Ca exchange.

Animals↗
PubMed1990

Mortality patterns of American merchant seamen 1973-1978.

Among 1,922 deaths in the American merchant marine population who were patients in the United States Public Health Service Hospital system in 1973-78, 46% were cancer associated. Eighteen percent of all deaths were due to heart disease. This pattern represented a reversal of the pattern found among patients of acute general care hospitals nationwide for the year 1975. Respiratory cancer amounted to 19.3% of the total, more than twice the number of such deaths among non-seamen patients. These patterns were consistent across a six-year time period. The finding in this study of an excess of cancer-associated deaths, particularly respiratory cancer, could be indicative of an occupationally associated risk. Data on the total population of merchant seamen at risk and of seamen deaths which may have occurred outside of the United States Public Health Service Hospital system are required to test more definitely the hypothesis of an occupational risk of cancer--especially lung cancer--among American merchant seamen.

Adolescent↗
PubMed1987

La3+, Mn2+, and Ni2+ effects on Ca2+ pump and on Na+-Ca2+ exchange in bullfrog ventricle.

45Ca washout from ventricles of the bullfrog was followed through an automated technique previously described. Lanthanum decreased the fractional rate of loss of 45Ca (by 67% at the saturating concentration, 1 mM, for this effect of the trivalent cation). In contrast, both manganous and nickel ions decreased the fractional rate of loss of 45Ca in 21 of the 30 ventricles studied. In the remainder of the experiments these ions increased this rate. This augmentation of the rate of 45Ca efflux by manganese and nickel could be converted consistently to an inhibition by experimental maneuvers known to increase the intracellular concentration of sodium-potassium-free washout solution, dihydroouabain. These results are consistent with the hypothesis that manganese and nickel increase 45Ca efflux through a process of sarcolemmal manganese-calcium (or nickel-calcium) exchange, operating through the sodium-calcium exchanger. Support for this interpretation was obtained in the further observation that the rate of loss of radioactive nickel from 63Ni-loaded ventricles was monotonically related to the extracellular concentration of calcium. Thus the augmenting effect of the divalent cations on 45Ca efflux appears to be mediated by the sodium-calcium exchanger. That the inhibitory effect arises from an action of the cations on the ATP-dependent component of 45Ca efflux is indicated by the fact that it disappears after vigorous ATP depletion in the presence of cyanide and 2-deoxy-D-glucose.

Animals↗
PubMed1987

Potentiation of contraction in bullfrog ventricle strips by manganese and nickel.

Sodium-lack contractures by strips of bullfrog ventricle were found to be increased in the presence of manganous ion (1-10 mM). In addition, peak force development was usually attained earlier in the presence of manganous ion and the rate of relaxation was decreased by nickel (0.7-2.0 mM), although the latter cation did not potentiate contractural force. Both manganese and nickel had only depressant effects on potassium-excess contractures, as well as on electrically stimulated twitches. Depressant effects of manganese and nickel on sodium-lack contractures were also found. These were smaller, the lower the extracellular sodium concentration and the higher the extracellular calcium concentration. When these well-known negative inotropic effects of the divalent cations were suppressed in sodium-free, calcium-rich media, their potentiating effects were unmasked, resulting in marked augmentation by these cations of potassium-excess contractures and of twitches, along with slowing of relaxation. Experimental maneuvers that have been reported to bring about entry of manganese into these cardiac cells did not increase the observed positive inotropic effect. It thus seems probable that these ions act on the membrane of the ventricle fiber. Also, in view of earlier evidence that they neither affect myofibrillar function nor induce calcium release from mitochondria, it is provisionally concluded that the mechanism of their potentiating effect on mechanical activation is due to their inhibition of calcium extrusion from the fibers, described in the accompanying paper.

Animals↗
PubMed1986

Direct control of contraction force of single frog atrial cells by extracellular ions.

We describe a method by which the ionic surround of an isolated frog heart cell can be changed within a small fraction of a contraction cycle while continuously measuring contraction force. With this method, we have investigated the effect on force development of changing the extracellular concentrations of Ca [( Ca]o) and Na [( Na]o) in the period between electrically driven contractions and during the rising phase of a contraction. Raising or lowering either [Ca]o or [Na]o more than 300 ms prior to a stimulus caused peak force of the next contraction to be changed 100% of the way to the steady-state value characteristic of the new ionic concentrations. Similar maneuvers at later times relative to the stimulus caused progressively smaller changes. Lowering [Ca]o from 2 to 1 mM or raising [Na]o from 78 to 110 mM 100 ms after stimulation brought twitch force 35 and 67% of the way to the new steady states, respectively. We conclude that extracellular Ca is the source of activator Ca in these cells and that extracellular Na plays a role in regulation of the intracellular Ca concentration early in the contraction cycle.

Animals↗
PubMed1985

The debate over diagnosis related groups.

With the advent of the Prospective Payment System (PPS) using Diagnosis Related Groups (DRGs) as a classification method, the pros and cons of that mechanism have been sharply debated. Grouping the comments into categories related to administration/management, DRG system and quality of care, a review of relevant literature highlights the pertinent attitudes and views of professionals and organizations. Points constantly argued include data utilization, meaningful medical classifications, resource use, gaming, profit centers, patient homogeneity, severity of illness, length of stay, technology limitations and the erosion of standards.

Attitude of Health Personnel↗
PubMed1985

Greater ATP dependence than sodium dependence of radiocalcium efflux in bullfrog ventricle.

45Ca efflux was studied in intact bullfrog ventricles following a 2-h period of loading with radiocalcium-containing Ringer solution. The cannulated ventricle was placed in a closed air-filled container to which were applied rhythmic, electronically timed, positive- and negative-pressure pulsations, which induced ventricular volume excursions. The mechanical arrangement and timing circuitry made it possible for each period to be as short in duration as 15 s. By use of this technique, penetration of the extracellular space by [14C]inulin was found to be complete within 30 s, and recovery of the inulin proceeded with a time constant of 17-24 s, indicating a completeness of recovery of 98% within 90 s. Washout of added 45Ca was quantitatively quite close to that of inulin, and in addition the estimated rate of sequestration of the isotope was slow enough to introduce only a small error into the experimental results. 45Ca efflux was only slightly (15%) sensitive to replacement of extracellular sodium but was profoundly sensitive to the inhibitors of ATP synthesis, cyanide and 2-deoxy-glucose.

Adenosine Triphosphate↗
PubMed1981

The program implications of administrative relationships between local health departments and state and local government.

A typology of organizational arrangements between state and local public health agencies was used as a framework within which the organizational environment of the local health department was studied for its effects on program development and implementation by local public health departments. Data collected in a national sample of local health officers were used in measuring the effect of four different patterns of administrative relationships on the selected characteristics of local health department programs. Important differences were observed among the four organizational types with regard to constraints on programs and program priorities, and health officers' perceptions of the primary functions of local health departments and sources of local health department funding. These findings were then used as a baseline from which to consider the possible impact of recent federal health budgetary proposals (specifically, block grants) both on existing patterns of intergovernmental relations and on the funding and operation of local health department programs. It was determined that the most likely general development arising from these proposed changes in federal budgetary policy is that the administrative control of state health agencies over those at the local level is likely to be enhanced. Other likely developments include changes in the programs and priorities of local health departments related to reductions in overall funding levels for human services and forced competition for fewer dollars by an enlarged constituency.

Community Health Services↗