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Biomedical subjects

P Katz

Publications and source records attributed to P Katz.

At least 55 records · Page 3Linked to original sources
PubMed1991

How surgical rituals enhance surgical science.

1. Although OR rituals seem to be anomalous with clinical training, they are adaptive and necessary for the performance of scientific and clinical roles and, in particular, the practice of surgery. 2. Surgical rituals maintain order, stability, and predictability while increasing the autonomy of the surgical staff to perform their clinical roles, which are based on scientific principles. 3. To remain scientific, clinicians must continuously question, test, and abandon outdated practices and accept new practices based on empirical knowledge.

Clinical Competence↗
PubMed1991

[Value of echography in salivary pathology].

Major advances in echography techniques over the past few years include the development of simple high performance units adapted to investigating the salivary glands. This non-traumatic, painless and inexpensive technique offers a means of rapid examination and is fully complementary to X-ray and xero and sialographic imagery, particularly in tumor pathology. The author gives a review of normal images then presents different lesions of the salivary gland.

Humans↗
PubMed1991

[Endoscopy of the salivary glands].

The author has developed an original method of exploration of the salivary glands: ultrafine fibroscopy. After briefly describing the equipment, the method and the indications, he demonstrates how it is now possible to extract stones via the natural passages using a miniaturized basket catheter, avoiding the need for more extensive surgery.

Endoscopy↗
PubMed1990

Effect of dystrophin gene deletions on mRNA levels and processing in Duchenne and Becker muscular dystrophies.

Muscle dystrophin mRNAs from Duchenne (DMD) and Becker (BMD) patients with internal deletion of the DMD gene were quantitated and sequenced. In all cases (eight DMD and three BMD), truncated mature transcripts were found, and their amount was correlated to the clinical phenotype and to the reading frame. We focused on four cases that were apparently not in agreement with the reading frame rule. In two DMD cases, slightly reduced amounts of in-frame truncated mRNA are present but no dystrophin is detected, suggesting impaired translation and/or instability of the protein. In two BMD patients with out-of-frame deletions, the presence of minor in-frame alternatively spliced mRNA species is congruent with the observed truncated dystrophin and the mild phenotype.

Base Sequence↗
PubMed1990

The association of cyclosporine with the 1-year costs of cadaver-donor kidney transplants.

Cyclosporine is associated with lower hospitalization costs for transplantation of cadaver kidneys. Whether this cost-lowering effect persists after discharge was assessed for 203 patients who received cadaver kidneys at the University of California, San Francisco, between July 1982 and June 1986. During the transplantation hospitalization period, cyclosporine was associated with significantly better graft survival (88.7% vs 71.0%) and lower (standardized) costs ($37,174 vs $52,983). Following discharge, however, there were no significant differences in graft survival, total charges ($29,716 vs $34,434), the number of readmissions, the total number of days hospitalized, or physician charges, although cyclosporine was associated with higher drug costs ($3885 vs $373). The results suggest that the initial association of cyclosporine with lower costs diminished substantially over time. For grafts that survive beyond several months, there may be little additional cost-reducing benefits of cyclosporine.

Adolescent↗
PubMed1990

Tryptophan-associated eosinophilic connective-tissue disease. A new clinical entity?

Seven patients who developed a syndrome of eosinophilia, connective-tissue disease, and cutaneous abnormalities while ingesting tryptophan were examined. Other clinical manifestations commonly seen were pulmonary symptoms, fever, lymphadenopathy, and the development of myopathy. Laboratory features included mild elevations of aldolase and lactate dehydrogenase levels, with essentially normal creatine kinase levels, erythrocyte sedimentation rates, and C-reactive protein levels. Biopsy findings included features of scleroderma, small-vessel vasculitis, fasciitis, and myopathy. Discontinuation of tryptophan administration and implementation of corticosteroid therapy were of some benefit in relieving the intense myalgias and cutaneous findings that developed. Although temporally related to tryptophan ingestion, it is unclear whether this substance, a metabolite, or a contaminant were causal. We speculate that the pathogenesis of this syndrome may relate to abnormalities in tryptophan metabolism.

Adult↗
PubMed1990

Natural killer cell-mediated lysis of Mycobacterium-avium complex-infected monocytes.

Since the precise mechanism of host responses to infection with Mycobacterium-avium complex (MAC) is unclear and since cytotoxic lymphocytes may be involved in the destruction of cells infected with intracellular pathogens, we investigated the ability of normal peripheral blood lymphocytes to kill MAC-infected monocytes in a short-term isotope release assay. Nylon wool-passed lymphocytes lysed MAC-infected but not uninfected monocytes during a 4-hr assay. Infected monocytes were less sensitive to cell-mediated killing than the standard natural killer (NK) cell-sensitive cell line K562, although the kinetics of lysis were similar. The release of lymphocyte-derived mediators such as tumor necrosis factor, interleukin-2 (IL-2), and interferon-alpha and -gamma could not be implicated as a cause of monocyte death. Through the use of cell-specific monoclonal antibodies plus complement, the phenotype of the effector cell was that of an NK cell (CD3 negative, partially CD8 negative, and CD16 positive). The use of highly purified, negatively selected NK cells confirmed these results. NK cell-mediated lysis of infected monocytes decreased MAC viability, indicating that this cytotoxic activity would not favor dissemination of the organism. The killing of MAC-infected monocytes was reduced by K562 cells, suggesting that these targets shared common recognition/binding structures. These results suggest that NK-cell function may be important in the prevention of or response to MAC infection and may help explain the predilection of AIDS patients to develop widespread disease.

Acquired Immunodeficiency Syndrome↗
PubMed1990

Increased risk of neisserial infections in systemic lupus erythematosus.

Survival in systemic lupus erythamatosus (SLE) continues to improve because of better ancillary care, earlier diagnosis, and earlier treatment. However, infection remains a leading cause of morbidity and mortality in this disease. Although corticosteroids and immunosuppresives increase the risk of opportunistic infection, the SLE patient is still most at risk from common bacterial pathogens. As the prototypic immune-complex disease, patients with active SLE have low circulating complement as well as a reticuloendothelial system (RES) saturated with immune complexes. It seems intuitive that SLE patients should be most at risk for organisms dependent for their removal on the RES or complement for opsonization or bacteriolysis. The current series presents four patients with SLE and disseminated neisseria infection and brings to 14 the number of patients in the literature with disseminated neisserial infection. They are typically young, female, with renal disease, and either congenital or acquired hypocomplementemia, and may present with all features of a lupus flare. Surprisingly, they are not all on corticosteroids or immunosuppressives and have some features that are unusual for non-SLE patients with these infections. There seems to be an over-representation of Nisseria meningitidis (despite potential reporting bias), and there ironically may be better tolerance with fewer fulminant complications in patients who have complement deficiencies. The best approach for the physician treating SLE is to immunize all SLE patients with available bacterial vaccines to N meningitidis and Streptococcus pneumonia, have a low threshold of suspicion for the diagnosis of disseminated neisserial or other encapsulated bacterial infection in the SLE patient who is sick, and to treat empirically with third generation cephalosporins after appropriate cultures.

Adolescent↗
PubMed1990

Modulation of suppression of mitogen-induced T cell-dependent B cell responses by natural killer cells.

We examined the ability of human natural killer (NK) cells to modualte pokeweed mitogen (PWM)-induced polyclonal antibody production. Highly purified NK cells inhibited plaque-forming cell (PFC) responses and this suppression could be substantially increased by preincubation of NK cells with the known enhancers of NK cell lytic activity, interferon (IFN)-alpha, IFN-gamma, and interleukin-2. Additionally, costimulation of NK cells with two anti-CD2 antibodies (9-1 and 9.6), which recognize different epitopes on the CD2 molecule, also augmented the inhibitory effect. When subpopulations of NK cells were assayed for suppressor cell activity, this activity was primarily mediated by NK cells bearing Leu-7 but not Leu-2 (CD8) antigens. Thus, alteration of NK cell lytic activity may have significant effects on the immunoregulatory functions of these cells, which may have important implications for the in vivo manipulation of cytotoxic responses.

Antibodies, Monoclonal↗
PubMed1990

Violence and social structure on mental hospital wards.

Significant differences in the incidence and distribution of violent behavior in mental hospital wards exist even when the diagnoses and other characteristics of patients are essentially the same. In an effort to compare the structure and predictability provided by organizational and interpersonal processes in violent and peaceful wards, the senior author spent 38 months in participant-observation and interviewing on six wards in three state mental hospitals. Patterns emerged in ward social organization and staff behavior that were associated with varying levels of violence. These patterns reinforced previous observation that violence is a symptom of disorder not only in the biological and psychological field but also in the sociocultural field. Violence was more frequent and more extreme in wards in which staff functions were unclear, and in which events such as activities, meetings or staff-patient encounters were unpredictable. Violence was less frequent and less extreme in wards characterized by strong psychiatric leadership, clearly structured staff roles, and events that were standardized and predictable. Ward social organization characterized by standardized, repeated, predictable behavioral and procedural rituals provided stability and autonomy that supported efforts to develop a therapeutic milieu.

Adult↗
PubMed1990

[The value of ultrasonography in salivary pathology].

Ultrasound has been increasingly used in recent years and thanks to high performance, easy to use apparatus, it can now be used for exploration of the salivary glands. This non invasive, painless and relatively inexpensive examination provides rapid visualisation of the salivary glands and is a useful adjunct to radio-xero-sialographic examination, particularly in tumour pathology. Following a review of normal appearances, the author briefly describes the various salivary gland lesions.

Humans↗
PubMed1989

The effect of cyclosporine on the use of hospital resources for kidney transplantation.

Over the past decade the clinical results of kidney transplantation have improved substantially, with much of the benefit being attributed to the introduction in late 1983 of the immunosuppressive drug cyclosporine. To assess the effect of cyclosporine on the use of hospital services, we studied 702 patients who received kidney transplants at the University of California, San Francisco, between July 1982 and June 1986. All services were priced in constant 1985 dollars, and multiple regression analysis was used to adjust for changing patient and hospital characteristics. The introduction of cyclosporine for patients receiving kidneys from cadavers was associated with a significantly shorter adjusted mean postoperative stay (26.4 days as compared with 37.0 for patients not taking the drug; P less than 0.0001) and lower adjusted mean hospital charges ($28,649 as compared with $37,895; P less than 0.0001), although cyclosporine was not associated with changes in the use of services by patients who received transplants from living related donors. Cyclosporine was also associated with a reduction in the use of certain ancillary services, such as laboratory tests and radiographic procedures. In patients without diabetes who received cadaver kidneys, a sequential cyclosporine regimen (in which a combination of antilymphoblast globulin, prednisone, and azathioprine was given before cyclosporine) reduced the use of hospital services even more than did a cyclosporine regimen in which the combination was not given. The results suggest that new medications, such as cyclosporine, that reduce the frequency of complications and improve outcomes may also reduce the use of hospital resources.

Adult↗
PubMed1989

Natural killer cells can enhance the proliferative responses of B lymphocytes.

In addition to lytic activity against malignant and virally transformed target cells, recent evidence has suggested that natural killer (NK) cells can modulate immune activities such as the suppression of B cell responses through noncytotoxic means. Using human B cells and highly purified autologous NK cells, we have demonstrated that NK cells can substantially augment the proliferative responses of B cells stimulated with the surface immunoglobulin crosslinking agents anti-IgM or Staphylococcus aureus Cowan strain I (SAC). This "enhancer" activity of NK cells was quite potent and was observed at an NK:B cell ratio as low as 0.05. Peak blastogenic responses of B cells cocultured with NK cells in the presence of B cell activators were observed at 2-3 days, similar to the responses of B cells in the absence of NK cells. Using the inhibitor of DNA synthesis mitomycin C, we determined that B cells and not NK cells were proliferating in cocultures of these lymphocytes stimulated with SAC. Activated B cells neither prevented the lysis of the isotope-labeled NK-sensitive target cell line K562 nor formed conjugates with NK cells, suggesting that cell contact was not a prerequisite for the effect. These studies have further expanded the functional repertoire of NK cells to include enhancer as well as suppressor and lytic activities.

Antibodies, Anti-Idiotypic↗