Hemolytic differences among artificial cardiac valves used in a ventricular assist pump

Ventricular assist devices (VADs) required for cardiac support may produce clinically significant hemolysis. VAD valves differ in both mechanics and hemodynamics. Therefore, we examined a ball valve, a modified tilting disc (MTD) valve, a polyurethane trileaflet valve, and a Björk-Shiley monostrut valve to determine their degrees of hemolysis. The valves were tested in a Pierce-Donachy VAD which pumped fresh bovine blood through a mock loop. Blood samples were analyzed for hematocrit and plasma hemoglobin, from which the indices of hemolysis were calculated. A one-way analysis of variance indicated significant differences between certain valves. The MTD was the most hemolytic. No significant hemolytic difference was found between the trileaflet and monostrut valves despite their different designs. The monostrut valve and the MTD valve were hemolytically very different despite their similar design. This study suggests that the valve type significantly affects the hemolysis produced by the VAD.

p493F12 kinase: a novel MAP kinase expressed in a subset of neurons in the human nervous system

Monoclonal antibody 3F12 identifies a cytoplasmic antigen of 49 kDa in human hippocampus and neocortex. The distribution of 3F12 immunoreactive neurons closely matches that of Alzheimer's disease (AD) targeted neurons in these areas. In some hippocampal neurons of AD patients, this antigen colocalizes with ALZ-50, indicating the presence of AD pathology in these neurons. Molecular characterization of the 3F12 cDNA revealed it to be a member of the MAP kinase family, showing 43% amino acid sequence identity to human extracellular related kinase 2 (p42mapk). We have confirmed that p493F12 kinase autophosphorylates both threonine and tyrosine residues, as expected for a MAP kinase. The p49 mRNA is expressed exclusively in the nervous system. In the brain, the distribution of these neurons closely corresponds to 3F12 antigen-bearing neurons. The p493F12 gene maps to the human chromosome 21q21 region, a region that may be important in the pathogenesis of AD and Down's syndrome.

Neuroendocrine modulation of tumor metastases. I. Effect of adrenalectomy on B16 melanoma metastases

There is increasing evidence to suggest a link between the neuroendocrine system and the immune system. Since it is well known that the immune response influences the establishment, progression or elimination of malignancy, we have examined the effects of adrenalectomy on B16 melanoma pulmonary tumor metastases and immune function in C57BL/6 mice to investigate the role of adrenal corticosteroids. Adrenalectomized mice were injected with 10(5) B16 melanoma cells on day 0. On day 9 the mice were sacrificed and the number of lung colonies counted. Adrenalectomized animals had a greater than 3 to 4-fold increase in the number of metastases as compared with sham operated animals. Steroid replacement therapy using dexamethasone delivered at 1 microgram/hr did not lead to any reduction in tumor metastases in adrenalectomized animals. These studies indicate that normal levels of adrenal steroids may influence the ability of tumor cells to colonize target organs and/or the ability of the immune system to mount an effective response.

A proposed method for assessing the performance of local public health functions and practices

OBJECTIVES

One of the objectives for the nation for the year 2000 requires that 90% of the population be served by a local health department effectively carrying out the core functions of public health. This study proposes a method whereby determinations can be made of the extent to which a local public health jurisdiction is served by core public health functions, as well as the extent to which the functions are rendered by the health department.

METHODS

Fourteen health departments under longitudinal study between 1979 and 1992 were studied. Respondents in each department completed a survey protocol using 81 indicators linked to standard public health functions and practices. Results are presented in graphic form, which provides a visual profile of public health performance for a local jurisdiction.

RESULTS

The graphic profiles successfully differentiate one jurisdiction from another, and within each jurisdiction they differentiate the performance levels of different public health practices. The method enables identification of the full range of public health providers.

CONCLUSIONS

Current definitions of public health practice have utility for evaluating public health performance. The validity of the proposed method deserves further study.

Aprotinin therapy for insertion of ventricular assist devices for staged heart transplantation

Bleeding after insertion of ventricular assist devices is a common problem which carries a major risk of immediate and late complications. We evaluated the safety and efficacy of aprotinin in six patients undergoing staged heart transplantation and compared the results with those of six patients who received no aprotinin. The groups did not differ significantly with respect to age, gender, preoperative cause of cardiomyopathy, or cardiopulmonary bypass time. Patients treated with aprotinin had a significant reduction in postoperative chest tube drainage (743 +/- 457 versus 2036 +/- 1184 cc, respectively, for aprotinin therapy versus no therapy; p = 0.047). Blood transfusion requirements were reduced in patients treated with aprotinin (2.2 +/- 2.2 versus 10.7 +/- 7.1 U respectively, for aprotinin therapy versus no therapy; p = 0.038). No demonstrable serious side effects were attributed to the aprotinin treatment. We conclude that aprotinin is effective in reducing bleeding and transfusion requirements without increasing the incidence of clinically significant renal dysfunction or thromboembolic events.

What's a woman doing in a place like this?

Medicine is not a science. It is an art that uses science to explore what William Harvey called "nature's closest secrets," that we may better minister to her children. We still need to remove some crackpot theories that have crept in, such as "holism." Even neurosurgery has a few. But we are beginning to humanize the traditional detached indifference and become the doctors we were meant to be. Our patients will be better for it. Society will be better for it. We will be better for it [1320]. In discussing the women's liberation movement in America, Reverend William Sloan Coffin once stated, "The woman who most needs liberating is the woman who lives inside of each man." This, I think, is the great awakening that the increasing influence of female physicians has brought about. Early twentieth century physicians, armed with a new science, became efficient fighters of disease. Disease was the enemy, the cure was the victory, and the patient was too often merely the environment in which the encounter was fought. This is what was taught in medical school and residency. It was necessary to learn the lesson well in order to be protected against the pain of others and to abort any insidious tendency to identify with their misery. Many teachers believed in preventing the enervating perils of "emotional involvement." This is not to say that physicians were unkind to their patients, merely that they kept their distance. Patients were treated with respect and even with a kind of formalized dignity. Physicians were as gentle as they knew how to be. But they were men apart. They towered over the sick as an adult towers over a child. Today something within men is being liberated. To a great extent, I believe that women physicians have been essential in bringing this change to medicine. We now know that physicians are not compromised by allowing themselves to feel some of what their patients feel. They are strengthened by it. A patient's life, the setting of his illness, the rending of his soul, the anguish of his family and the hope for his recovery have all become as much a part of good care as knowledge of the serum sodium and what to do about it. Men have become better nurturers, more empathetic. And the thing that is being liberated from inside men is something that society has always seen as a feminine quality. The peak of the healer's art is in bringing both science and empathy to bear on disease. This is what being a physician should mean.(ABSTRACT TRUNCATED AT 400 WORDS)

The use of long-duration current pulses to assess nerve survival

This study investigated the usefulness of long-duration current pulses in assessing the status of the auditory nerve in ears with various degrees of retrograde neural degeneration. Guinea pigs were deafened with aminoglycosides prior to acute implantation of the cochlea and collection of electrically evoked auditory brainstem responses (EABRs). Analysis of wave I evoked with long-duration current pulses suggests that this evoked response is sensitive to degeneration of the peripheral processes of the auditory nerve. Correlations with spiral ganglion cell density show that EABR measures obtained with long-duration pulses are comparable to those previously established for estimating nerve survival. Further analysis indicates that this measure may provide unique information about the degenerative state of the nerve. Threshold EABR measures using long-duration pulses are evidently more place-specific than other measures. Also, results suggest that long-duration pulses may be sensitive to two phases of the degenerative process: degradation of the peripheral processes and subsequent degeneration of neural processes central to the spiral ganglion.

Somataglycan-S: a neuronal surface proteoglycan defines the spinocerebellar system

The formation and maintenance of functionally specific neuronal networks may depend on specific proteoglycans localized to the surface membranes of a subset of neurons. Monoclonal antibody (MAb) 6A2 labeled a distinct subset of CNS neurons: the somas and proximal dendrites of cells making up the spinocerebellar and reticular systems. These pathways contribute to proprioceptive and exteroceptive functions. Ultrastructurally, MAb 6A2 immunoreactivity was distributed focally along the cell surface membranes and the adjacent extracellular space. On western blots of immunoaffinity-purified preparations from cerebellar homogenates, a major, broad band of approximately 400 kDa is labeled by MAb 6A2. Increased electrophoretic mobility of the purified antigen after digestion with chondroitinase ABC and keratanase suggests that the antigen is a proteoglycan bearing chondroitin sulfate and keratan sulfate glycosaminoglycans. Unsulfated N-acetyl-galactosamine residues linked to unsaturated uronic acid constituted the initial disaccharide in the chondroitin sulfate glycosaminoglycan chains. N- and O-linked oligosaccharides on the core protein were detected by the biotinylated lectins wheat germ agglutinin and Jacalin, respectively, and by MAb anti-HNK-1. Lyase and glycosidase digests result in a 280-kDa band. This proteoglycan, somataglycan-S, may provide a key to the role of glycoconjugates in determining neuronal diversity and system specificity.

Autosomal dominant Lewy body parkinsonism in a four-generation family

We report a family with autosomal dominant parkinsonism. The propositus developed parkinsonism at a relatively young age (45 years) and came to autopsy after a 6-year illness. She had typical features of Parkinson's disease except for an absence of rest tremor, although this was present in other family members. A diagnosis of Lewy body parkinsonism was confirmed by neuropathological examination. Additional pathological features included the presence of cortical Lewy bodies and anti-ubiquitin-positive neurites in the cornu Ammonis 2 and 3 (CA2-3) region of the hippocampus. This kindred is similar both clinically and pathologically to a few previously reported pedigrees, further strengthening recent evidence of a genetic etiology of some forms of Parkinson's disease.

A screening survey to assess local public health performance

Current studies are attempting to develop a national surveillance system to measure the extent that populations are served by local departments carrying out the core functions of public health. Early phases of the study featured observations on 14 health departments that have been subjects of a longitudinal study. These departments were surveyed using a protocol with 81 different indicators. The results permitted distinctions to be made among the departments on levels of performance according to core functions and their associated practices. To simplify the survey protocol so that it might be suitable for use with a large number of local public health jurisdictions, a subset of 26 indicators was selected from the previously developed protocol. Each indicator in the subset was linked with one of the three core functions of public health and with one of the associated practices. In an effort to display correlation between scores on the simplified survey and those in the full survey, scatter plots were prepared for overall scores and for those pertaining to each function and practice. Stepwise regressions were done to determine which queries or groups of queries were most predictive of variations in the screening responses. Four questions accounted for 96 percent of the variance in responses for overall performance. Results suggest that a three-tiered approach to the evaluation of local public health performance might be feasible. For the study departments, responses to four questions could be used to screen overall public health performance; responses to 26 questions could be used to yield information about performance of each of the three core public health functions; and responses to 84 questions could be used to yield more detailed information about performance for each of 10 public health practices. Experience with a larger set of departments might revise the number and nature of the screening queries.

Zymographic analysis of extracellular, released and cell-associated proteases of rat interleukin 2-activated natural killer (A-NK) cells

The biochemical properties of heretofore uncharacterized extracellular proteases of rat interleukin-2-activated natural killer (A-NK) cells were investigated. Following p-aminobenzamidine- and D-phenylalanine-agarose affinity chromatography both trypsin- and chymotrypsin-like protease activities were found. Zymography revealed "trypsin-like" activities, with apparent molecular weights of approximately 42 kDa to 20.5 kDa, and "chymotrypsin-like" activities of approximately 27 kDa, to 22 kDa. These proteases might contribute to diverse NK cell functions, and the characteristics of these proteolytic activities are compared with those of granzymes of lytic granules and the proteasome of A-NK cells.

Interleukin-2 (IL-2) activated natural killer (A-NK) cells: binding to microvascular endothelial cells and BRM enhancement of cytolytic activity

A syngeneic in vitro system was developed for investigation of the binding of purified murine interleukin-2 (IL-2) activated natural killer (A-NK) cells to murine microvascular endothelial cells. This system is potentially useful as a model to investigate biochemical and molecular events underlying the binding of A-NK cells to microvascular endothelial cells within metastases in vivo that we have previously noted using electron microscopy. A-NK/endothelial cell binding in the syngeneic system was compared with the binding of allogeneic A-NK cells to the endothelial cells. Among test agents used to pretreat the A-NK cells for modulation of binding, lipopolysaccharide (LPS) most consistently enhanced binding. Additionally, test agents were also used in concurrent assays of A-NK cytolytic activity versus YAC-1 and P815 tumor cell targets. Polyinosinic: polycytidylic acid (poly IC), and gamma interferon (gamma IFN) were among the test agents which enhanced A-NK cell cytolytic activity.