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Biomedical subjects

D Fishman

Publications and source records attributed to D Fishman.

At least 37 records · Page 2Linked to original sources
PubMed1999

Reliability of echocardiographic assessment of left ventricular structure and function: the PRESERVE study. Prospective Randomized Study Evaluating Regression of Ventricular Enlargement.

OBJECTIVES: The study was done to evaluate reliability of echocardiographic left ventricular (LV) mass. BACKGROUND: Echocardiographic estimation of LV mass is affected by several sources of variability. METHODS: We assessed intrapatient reliability of LV mass measurements in 183 hypertensive patients (68% men, 65 +/- 9 years) enrolled in the Prospective Randomized Enalapril Study Evaluating Regression of Ventricular Enlargement (PRESERVE) trial after a screening echocardiogram (ECHO) showed LV hypertrophy. A second ECHO was repeated at randomization (45 +/- 25 days later). Two-dimensional (2D)-guided M-mode or 2D linear measurements of LV cavity and wall dimensions were verified by one experienced reader. RESULTS: Mean LV mass was similar at first and second ECHO (243 +/- 53 vs. 241 +/- 54 g) and showed high reliability as estimated by intraclass correlation coefficient (RHO) = 0.93. Within-patient 5th, 10th, 90th and 95th percentiles of between-study difference in LV mass were -32 g, -28 g, +25 g and +35 g. Mean LV mass fell less from the first to the second ECHO than expected from a formula to predict regression to the mean (2 +/- 19 vs. 17 +/- 12 g, p < 0.001). Reliability was also high for LV internal diameter (RHO = 0.87), septal (RHO = 0.85) and posterior wall thickness (RHO = 0.83). Substantial or moderate reliability was observed for measures of LV systolic function and diastolic filling (RHO from 0.71 to 0.57). CONCLUSIONS: Left ventricular mass had high reliability and little regression to the mean; between-study LV mass change of +/-35 g or +/-17 g had > or = 95% or > or = 80% likelihood of being true change.

Aged↗
PubMed1998

The effect of novel polymorphisms in the interleukin-6 (IL-6) gene on IL-6 transcription and plasma IL-6 levels, and an association with systemic-onset juvenile chronic arthritis.

During active disease, patients with systemic-onset juvenile chronic arthritis (S-JCA) demonstrate a rise and fall in serum interleukin-6 (IL-6) that parallels the classic quotidian fever. To investigate the possibility that this cytokine profile results from a difference in the control of IL-6 expression, we examined the 5' flanking region of the IL-6 gene for polymorphisms. A G/C polymorphism was detected at position -174. In a group of 383 healthy men and women from a general practice in North London, the frequency of the C allele was 0.403 (95% confidence interval 0.37-0.44). In comparison, 92 patients with S-JCA had a different overall genotype frequency, especially those with onset of disease at < 5 yr of age. This was mainly due to the statistically significant lower frequency of the CC genotype in this subgroup. When comparing constructs of the 5' flanking region (-550-+61 bp) in a luciferase reporter vector transiently transfected into HeLa cells, the -174C construct showed 0.624+/-0.15-fold lower expression than the -174G construct. After stimulation with LPS or IL-1, expression from the -174C construct did not significantly change after 24 h, whereas expression from the -174G construct increased by 2.35+/-0.10- and 3.60+/-0.26-fold, respectively, compared with the unstimulated level. Plasma levels of IL-6 were also measured in 102 of the healthy subjects, and the C allele was found to be associated with significantly lower levels of plasma IL-6. These results suggest that there is a genetically determined difference in the degree of the IL-6 response to stressful stimuli between individuals. The reduced frequency of the potentially protective CC genotype in young S-JCA patients may contribute to its pathogenesis. Similarly the individual's IL-6 genotype may be highly relevant in other conditions where IL-6 has been implicated, such as atherosclerosis.

Adolescent↗
PubMed1998

No association of the I1307K APC allele with ovarian cancer risk in Ashkenazi Jews.

Familial adenomatous polyposis is a dominantly inherited colon cancer syndrome associated with germ-line mutations in the APC tumor suppressor gene. An APC gene sequence alteration, the I1307K allele, occurs in 6% of the Ashkenazi Jewish population and is reported to double the risk for colorectal cancer. We screened a population of 190 Ashkenazi women who were diagnosed with epithelial ovarian carcinoma for the I1307K variant and measured the effect of this allele on the risk for cancer development in their first-degree relatives. We identified the I1307K allele in 7.9% (15 of 190) of our ovarian cancer cases. The average age of ovarian cancer diagnosis in carriers of the I1307K allele (57.5 years) was not statistically different than the age for noncarriers (56.4 years; P = 0.70). Among the 1087 first-degree relatives, there were 23 cases of colorectal cancer; 3 of 100 relatives of probands with the I1307K allele (3.0%) had a history of colorectal cancer versus 20 of 987 relatives of probands without the I1307K allele (2.1%; relative risk, 1.48; 95% confidence interval, 0.45-4.88; P = 0.462). Relatives of the I1307K carriers had a risk of 38.0% for developing any cancer to age 80, similar to the risk for relatives of noncarriers of the I1307K allele (42.1%; P = 0.86). The average age of diagnosis of cancer of any type was not different between relatives of carriers (59.0 years) and noncarriers (60.4 years). In the Ashkenazi Jewish population, the I1307K allele is unlikely to increase the risk of ovarian cancer or of cancer in general.

Biomarkers, Tumor↗
PubMed1998

[Non-invasive mechanical ventilation as treatment for severe pneumonia in an HIV positive patient].

A 27 year-old HIV+ patient was admitted to the hospital for probable Pneumocystis carinii pneumonia (PCP). He was severely dyspneic, with respiratory rate of 44 x min and accessory respiratory muscle contraction. The alveolar-arterial quotient was 0.35. Ventilation by BiPAP was applied during 12 hours. After BiPAP a/AO2 was O.42, with amelioration of dyspnea, decrease of respiratory rate (25 x min) and without using of accessory respiratory muscles. No complications occurred. At the end of hospital stay a/AO2 was 0.68. CPAP application but not BiPAP has been reported in PCP. Our patient showed evident improvement after BiPAP, suggesting that this method of ventilation is useful and should be incorporated to the routine management of these patients.

AIDS-Related Opportunistic Infections↗
PubMed1997

Epidermal growth factor regulates protein kinase A activity in murine fibrosarcoma cells: differences between metastatic and nonmetastatic tumor cell variants.

The interplay between cyclic AMP (cAMP)-dependent protein kinase A (PKA)- and p21ras-mediated signaling pathways is expected to determine further loss, maintenance, or modulation of differentiation and proliferation of a particular cell. Therefore, the relationship and nature of the cross-talk between these two major signaling systems are of utmost importance to the understanding of these processes in both normal and neoplastic cells. In view of their paramount physiological importance, one would expect the existence of a well-controlled bidirectional interaction between these pathways, which would be more appropriate and in agreement with basic principles of cellular homeostasis. However, based on the discovery that activated PKA may inhibit ras-mediated translocation of c-Raf-1 to the plasma membrane, it is generally accepted that the cross-talk between cAMP/PKA and p21ras-mediated signal transduction pathways is unilateral, i.e., that the activation of PKA regulates growth factor receptor protein tyrosine kinase-mediated signaling. To challenge the validity of a unilateral approach, we decided to test the possible existence of cross-talk of a bidirectional nature between the aforementioned signaling pathways at different stages of malignant differentiation. For that purpose, we investigated the nature of the cross-talk existing between a known receptor protein tyrosine kinase-epidermal growth factor receptor (EGFR) and PKA in highly metastatic and nonmetastatic cloned variants of a murine fibrosarcoma (T-10). Our study revealed the existence of principal differences in PKA activity between metastatic and nonmetastatic cloned fibrosarcoma variants that may be due to the differential expression and membrane translocation of the p21(Ki-ras) small mass G-protein. Most importantly, our experiments have demonstrated the existence of a novel character of interactions between EGFR and PKA, because the ligation of the EGFR by epidermal growth factor in the metastatic variant induced a high activity of PKA. These findings are of prime importance, because they reveal the existence of a new relationship between two major signal transduction pathways in mammalian cells, i.e., the existence of a bilateral interaction between the ras- and cAMP/PKA-mediated signal transduction pathways. Furthermore, the fact that two tumor cell variants originating in the same tumor and differing in their metastatic capacity differ as well in the nature of the cross-talk between major signal generation systems imposes new challenges for the future use of biological response modulators to cure cancer and restrict metastatic spread.

3T3 Cells↗
PubMed1997

The effects of measles virus persistent infection on AP-1 transcription factor binding in neuroblastoma cells.

Measles virus (MV) persistence in brain cells has broad effects on different cellular functions. We have previously shown that NS20Y clone, originally derived from C1300 neuroblastoma cells, persistently infected with MV (NS20Y/MS), displays constitutively elevated levels of c-fos and PKC mRNAs, implying MV-mediated effects on transcriptional regulation. Nonetheless, the mode by which virus affects the transcriptional machinery still remains obscure. In order to define this phenomenon, we studied the binding properties of major transcription factors (AP-1 and NFkappaB) in NS20Y/MS cells. Using electrophoretic mobility shift approach (EMSA) with the appropriate oligonucleotide probes, we have found that the persistent MV infection does not affect NFkappaB binding, while the AP-1 binding was significantly decreased. Similar inhibition was not observed in NS20Y cells acutely infected with MV. Anti-measles antibody-mediated restriction of viral gene expression restored AP-1 binding, thus suggesting that measles virus proteins may affect the components of the host transcriptional machinery.

Animals↗
PubMed1997

Membrane-associated insulin-like growth factor-binding protein-3 inhibits insulin-like growth factor-I-induced insulin-like growth factor-I receptor signaling in ishikawa endometrial cancer cells.

The function of cell surface-associated insulin-like growth factor-binding proteins (IGFBPs) is controversial. Both inhibition and facilitation of IGF action as well as IGF-independent effects have been reported. We examined the influence of endogenous cell surface-associated IGFBPs on IGF-I receptor (IGF-IR) function in Ishikawa endometrial cancer cells by comparing the effects of IGF-I and its truncated analog des-(1-3)-IGF-I on several components of the IGF-IR signal transduction pathway in the absence of significant amounts of soluble IGFBPs. IGF-I and des-(1-3)-IGF-I are known to have similar affinities for IGF-IR, although the affinity of des-(1-3)-IGF-I for IGFBPs is greatly reduced. Here we show that the two ligands were equipotent not only in IGF-IR binding but also in receptor activation in NIH 3T3 cells overexpressing IGF-IR and possessing a relatively small number of cell surface-associated IGFBPs. In contrast, des-(1-3)-IGF-I manifested a remarkably higher potency as compared with IGF-I in inducing short and middle term cellular responses in IGF-IR-transfected Ishikawa endometrial cancer cells possessing a high number of both the receptor and the cell membrane-bound IGFBP-3. Thus, this difference in the effects of IGF-I and des-(1-3)-IGF-I can be attributed to the attenuation of IGF-I-mediated IGF-IR signaling by membrane-bound IGFBP-3.

3T3 Cells↗
PubMed1997

Splenic involvement in rheumatic diseases.

OBJECTIVES: To assess the major reports of splenic involvement in the rheumatic diseases and to highlight several conditions in which potentially life-threatening splenic complications may occur. METHODS: A search of the Medline database ('SilverPlatter': 1966 to 1997) was conducted for all English-language entries related to the spleen and the major rheumatic diseases. Original articles were reviewed from the bibliographies of these Medline-sourced articles. The major rheumatological textbooks were also reviewed for original references. RESULTS: Patients with rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), and polyarteritis nodosa (PAN) are at risk of experiencing spontaneous splenic rupture. Splenomegaly is common in both uncomplicated RA and as a feature of Felty's syndrome, in which the patient may be at risk of splenic abscess formation, again a possible complication of SLE and also PAN. Massive splenomegaly appears to be specific to SLE and may be confused with a malignant process. Abnormal splenic function has been documented in RA, SLE, and Wegener's granulomatosis. The spleen may show areas of infarction in several conditions, notably SLE and Wegener's granulomatosis. Splenic atrophy is not uncommon in SLE and may be associated with functional asplenia and a co-incident risk of potentially fatal infection with capsulated organisms. CONCLUSIONS: Serious and occasionally fatal complications within the spleen occur in many rheumatic diseases. Prompt recognition of these complications is important.

Adult↗
PubMed1997

What happens after discharge? Return hospital visits after ambulatory surgery.

The purpose of this study was to examine the frequency of return hospital visits after ambulatory surgery discharge and to identify any predictor variables for its occurrence. A retrospective review of hospital records for all patients returning to the same hospital within 30 days after ambulatory surgery was conducted. Data on return hospital visits that resulted in rehospitalization (as an inpatient or to the ambulatory surgery unit [ASU]) or treatment as an outpatient in the emergency room were recorded. A total of 6243 patients underwent ambulatory surgery over 12 consecutive months and 187 returned to the same hospital of which 1.3% were for complications. Of all the returns, 54% returned to the emergency room (ER) and 46% were rehospitalized as inpatients or to ASU. To identify factors associated with an increased likelihood of return, two case controls for each return visit were obtained from medical records of ambulatory surgical patients operated on during the same time period. Results of the multivariate analysis on the matched case controls identified urology as the only significant surgical service that predicted returns. (Odds ratio 27.87; confidence interval [CI] 3.78-74.86; P = 0.0002). A separate analysis of the most common ASU procedures performed identified two surgical procedures that predicted hospital return as compared with overall ambulatory surgery population: patients undergoing varicocelectomy and hydrocelectomy procedures were 8.3 times more likely to return (CI 2.090-23.75; P = 0.0042); patients undergoing dilation and curettage were three times as likely to return (CI 1.78-5.55; P = 0.0002). Bleeding was the most common reason for all hospital returns (41.5%), with 76.5% of these patients treated and discharged through the ER. The increased likelihood of return visits after urology procedures warrants further evaluation. As patients with bleeding were most likely to return to the ER and discharged, more effective pre- and postprocedure patient education may further reduce this occurrence. Better informing patients regarding the prognosis of bleeding, and advising them of medical alternatives, could reduce inappropriate patient returns to the ER.

Adult↗
PubMed1997

L-canavanine, an inhibitor of inducible nitric oxide synthase, improves venous return in endotoxemic rats.

OBJECTIVE: To investigate the hemodynamic effects of L-canavanine (an inhibitor of inducible, but not of constitutive, nitric oxide synthase) in endotoxic shock. DESIGN: Controlled, randomized, experimental study. SETTING: Animal laboratory. SUBJECTS: Wistar rats. INTERVENTIONS: Rats were anesthetized with pentobarbital, and hemodynamically monitored. One hour after an intravenous challenge with 5 mg/kg of Escherichia coli endotoxin, the rats were randomized to receive a continuous infusion of either L-canavanine (20 mg/kg/hr; n = 8) or vehicle only (isotonic saline, n = 11). In all animals, the infusion was given over 5 hrs at a rate of 2 mL/kg/hr. These experiments were repeated in additional rats challenged with isotonic saline instead of endotoxin (sham experiments). MEASUREMENTS AND MAIN RESULTS: Arterial blood pressure, heart rate, thermodilution cardiac output, central venous pressure, mean systemic filling pressure, urine output, arterial blood gases, blood lactate concentration, and hematocrit were measured. In sham experiments, hemodynamic stability was maintained throughout and L-canavanine had no detectable effect. Animals challenged with endotoxin and not treated with L-canavanine developed progressive hypotension and low cardiac output. After 6 hrs of endotoxemia, both central venous pressure and mean systemic filling pressure were significantly below their baseline values, indicating relative hypovolemia as the main determinant of reduced cardiac output. In endotoxemic animals treated with L-canavanine, hypotension was less marked, while cardiac output, central venous pressure, and mean systemic filling pressure were maintained throughout the experiment. L-canavanine had no effect on the time-course of hematocrit. L-canavanine significantly increased urine output and reduced the severity of lactic acidosis. CONCLUSIONS: Six hours after an endotoxin challenge in rats, low cardiac output develops, which appears to be primarily related to relative hypovolemia. L-canavanine, a selective inhibitor of the inducible nitric oxide synthase, increases the mean systemic filling pressure, thereby improving venous return, under these conditions.

Animals↗
PubMed1997

L-canavanine improves organ function and tissue adenosine triphosphate levels in rodent endotoxemia.

Overproduction of NO by an inducible NO synthase (iNOS) plays a major role in the pathophysiology of septic shock, and selective inhibition of iNOS in this setting could be of great therapeutic value. In the present study, we evaluated the effects of L-canavanine, a selective iNOS inhibitor, in an animal model of septic shock, with a particular focus on tissue oxidative metabolism and organ functions. Anesthetized rats challenged intravenously with lipopolysacharide (LPS) were treated after 1 h by a continuous infusion of either L-canavanine (20 mg/kg/h; n = 11) or an equivalent volume of saline (2 ml/kg/h; n = 17) given for 4 h. A third group (sham rats; n = 9) did not receive LPS and was treated with a continuous infusion of saline (2 ml/kg/h). At the end of experiments, biopsies were taken from the liver, the kidney, and the small intestine for the measurement of tissue ATP. LPS induced a progressive fall in blood pressure, accompanied by biologic signs of liver and kidney failure, concomitant with a marked decrease in tissue ATP stores. L-canavanine largely prevented hypotension and significantly increased tissue ATP while reducing the signs of organ dysfunction. These effects were associated with a significant improvement in survival during the 5 h of study. We conclude that L-canavanine not only reduces hypotension in endotoxin shock but also largely prevents the detrimental consequences of LPS on tissue oxidative metabolism and major organ functions, allowing a decrease in endotoxin lethality.

Adenosine Triphosphate↗
PubMed1989

Biocompatibility of hemoglobin solutions. I. Reactions of vascular endothelial cells to pure and impure hemoglobins.

Hemoglobin (Hb) solutions can cause vasoconstriction and activation of intravascular coagulation. Because the endothelium plays a major role in the regulation of vascular tone and hemostasis, a study was conducted of human umbilical vein endothelial cells (EC) incubated with various Hbs. Cell injury was evaluated by electron microscopy and the release of lactic dehydrogenase, H2O2, and procoagulant "tissue factor." Cell reaction was assessed by the measurement of 6-keto-prostaglandin F (PGF)1 alpha (metabolite of prostacyclin) and thromboxane B2 (metabolite of thromboxane A2). Incubation with unmodified bovine hemoglobin for 24 h caused no cell injury and a reaction characterized by 48.4 +/- 8.2% increase in 6-keto-PGF1 alpha production, accompanied by 40.2 +/- 9.4% reduction in thromboxane (Tx)B2 (compared with a control group of EC incubated with saline solution). Incubation with a nonpure Hb solution (Hb plus red blood cell membrane aminophospholipids; a-PLs) caused cell injury with significant release of tissue factor, plus a reaction characterized by 97.5 +/- 12.5% increase in TxB2 production accompanied by 25.3 +/- 3% reduction in 6-keto-PGF1 alpha. A second nonpure Hb [Hb plus bacterial environmental endotoxin (E)] caused cell injury, the release of tissue factor, and increased production of both prostaglandins, with greater release of TxB2 (197 +/- 17%) than of 6-keto-PGF1 alpha (112 +/- 8.3%). These data indicate that the endothelium reacts differently to pure and nonpure hemoglobins. The biocompatibility of Hb solutions, with regard to vasoconstriction and activation of intravascular coagulation, depends on the absence of stromal a-PLs and bacterial E.

Animals↗
PubMed1988

Ocular hypotensive efficacy of 0.25% levobunolol instilled once daily.

The authors evaluated the efficacy of once-daily treatment with levobunolol in patients with primary open-angle glaucoma or ocular hypertension in an open-labeled, two-phase titration clinical trial. All patients started the study using 0.25% levobunolol administered once daily for 3 months (phase I). If a patient's intraocular pressure (IOP) was not controlled with this concentration of levobunolol, the concentration was increased to 0.5% administered once daily for 3 months (phase II). During phase I, a significant reduction in IOP was observed in 21 of the 29 patients (72%), with an average IOP reduction of 24%. During phase II, in six patients whose IOP was reduced inadequately with 0.25% levobunolol, one had a significant reduction in IOP with 0.5% levobunolol. The authors concluded that levobunolol, instilled once daily at a concentration of 0.25%, was effective in significantly reducing IOP in the majority of the patients evaluated.

Adult↗