Phosphorylation of eIF4E at a conserved serine in Aplysia

We have cloned eIF4E from the marine mollusk, Aplysia californica. The sequence of eIF4E from Aplysia is more similar to vertebrate eIF4Es than to other invertebrate sequences. Aplysia eIF4E is encoded by two tissue-specific RNAs. Antibodies raised to the carboxyl terminus of eIF4E recognize a 29-kDa protein that can bind to 7-methyl-GTP caps. The phosphorylation site identified in mammalian eIF4E is conserved in the Aplysia homologue, and an Aplysia eIF4E fusion protein is phosphorylated well by both Aplysia protein kinase C isoforms. However, protein kinase C phosphorylates both Ser-207 and Thr-208 in vitro, while only Ser-207 is phosphorylated in vivo. We have confirmed that Ser-207 is phosphorylated in vivo by raising a phosphopeptide antibody to this site. This antibody will be useful in determining the signal transduction pathways leading to eIF4E phosphorylation in Aplysia.     

Underutilization of warfarin in older persons with chronic nonvalvular atrial fibrillation at high risk for developing stroke

OBJECTIVE: To investigate the prevalence of the use of warfarin to maintain an international normalized ratio (INR) between 2.0 and 3.0 in older persons with chronic nonvalvular atrial fibrillation (AF), and without contraindications to warfarin, who are at high risk for developing new thromboembolic (TE) stroke. DESIGN: A retrospective analysis of charts from all older persons seen during 1997 at an academic hospital-based geriatrics practice. SETTING: An academic hospital-based geriatrics practice staffed by fellows in a geriatrics training program and full-time faculty geriatricians. PATIENTS: Three hundred eighty men and 1183 women, mean age 80+/-8 years (range 59 to 103 years), were included in the study. MEASUREMENTS AND MAIN RESULTS: Of 1563 persons studied, 141 (9%) had chronic nonvalvular AF. Of 141 persons with AF, 127 (90%) were at high risk for developing TE stroke because they had either a previous thromboembolism, congestive heart failure, or echocardiographic evidence of abnormal left ventricular systolic function; a systolic blood pressure >160 mm Hg; or they were women older than 75 years of age. Of the 127 persons with AF at high risk for developing TE stroke, three (2%) had contraindications to warfarin. Of the 124 persons with AF at high risk for developing TE stroke and no contraindications to warfarin, 61 (49%) were treated with warfarin to maintain an INR between 2.0 and 3.0, and 45 (36%) were treated with 325 mg aspirin daily. Of 14 persons with AF at low risk for developing TE stroke, one (7%) was treated with warfarin to maintain an INR between 2.0 and 3.0, and six (43%) were treated with 325 mg aspirin daily. CONCLUSIONS: Warfarin is underutilized as a treatment to maintain an INR between 2.0 and 3.0 in older persons with chronic nonvalvular AF at high risk for developing TE stroke.     

National trends in the epidemiology of prostate cancer, 1973 to 1994: evidence for the effectiveness of prostate-specific antigen screening

OBJECTIVES: The use of prostate-specific antigen (PSA) to screen for prostate cancer remains controversial. Although it is still too early to measure directly the effects of PSA screening on mortality, we examined changes in the epidemiology of prostate cancer to determine if there is other evidence of the effectiveness of PSA as a screening tool. METHODS: We examined trends in age at diagnosis, and age-adjusted trends in stage and grade at diagnosis, for 140,936 white and 15,662 African American men diagnosed with prostate cancer from 1973 to 1994 in the National Cancer Institute's Surveillance Epidemiology and End Results data base. RESULTS: We found a significant downward trend in age at diagnosis, concomitant with a downward shift in stage of disease at diagnosis, starting with the advent of the PSA era in the late 1980s. We noted most cancers detected since the PSA era to be moderately well differentiated (International Classification of Diseases of the World Health Organization grade 2; Gleason score 5, 6, 7) and organ confined. Although findings were similar for both whites and African Americans, African Americans experienced a greater increase in poorly differentiated disease than did whites. CONCLUSIONS: Changes in the epidemiology of prostate cancer since the advent of the PSA era are consistent with the introduction of an effective screening test. This is evidenced by an increase in detection of significant prostate cancer in individuals who will likely benefit from treatment.     

Pulmonary function in horses with recurrent airway obstruction after aerosol and parenteral administration of beclomethasone dipropionate and dexamethasone, respectively

OBJECTIVE: To determine changes in clinical signs of disease and response to pulmonary function testing in horses with recurrent airway obstruction (heaves) after aerosol and parenteral administration of beclomethasone dipropionate and dexamethasone, respectively. ANIMALS: 6 horses with inducible and reversible heaves. PROCEDURE: Episodes of heaves were induced by exposure (challenge) to moldy hay and straw for 7 days. Horses were assigned to treatment groups (aerosolized beclomethasone dipropionate, parenterally administered dexamethasone, aerosolized propellant [control]), and respiratory frequency and subjective assessment of respiratory effect were determined twice daily. Maximal change in pleural pressure (delta-Pplmax), pulmonary resistance (RL), and dynamic compliance (Cdyn) was determined on days 0, 7, 10, 14, and 21. RESULTS: The RL and delta Pplmax were increased, and Cdyn was decreased in all horses in response to natural challenge. Beclomethasone reduced RL on day 10, reduced delta Pplmax on days 14 and 21 and increased Cdyn on day 14. Dexamethasone reduced RL and delta Pplmax on days 10, 14, and 21 and increased Cdyn on days 10 and 14. Respiratory effort (subjective assessment) improved after 2 and 3 days of beclomethasone and dexamethasone administration but rebounded to pretreatment values 1 and 3 days after discontinuation of drugs. CONCLUSIONS: Pulmonary function testing responses and clinical signs of airway obstruction were improved by administration of beclomethasone. The magnitude of response to aerosolized beclomethasone generally was less marked than the response to parenterally administered dexamethasone. Higher or more frequent dosing of aerosolized beclomethasone may be necessary to achieve the anti-inflammatory response to parenterally administered dexamethasone.     

Human beta-glucuronidase. I. Recognition and uptake by animal fibroblasts suggests animal models for enzyme replacement studies

As part of an effort to develop an animal model for studies of uptake of human beta-glucuronidase, fibroblasts were established from primary explants of connective tissue from nine different animal species, and examined for their ability to take up human platelet beta-glucuronidase. Endogenous fibroblast beta-glucuronidase was inactivated by heating extracts to 65 degrees for 30 min. Human beta-glucuronidase was stable to this treatment. Uptake of human beta-glucuronidase by animal fibroblasts was measured as heat-stable beta-glucuronidase present in fibroblasts after exposure to partially purified human platelet beta-glucuronidase for 48 hr. Althought all animal fibroblasts examined exhibited some uptake capacity for human beta-glucuronidase, the uptake capacity of different animal fibroblasts varied over a 10-fold range. The uptake capacity of bovine fibroblasts was at least 80% that of human fibroblasts. Rat and hamster fibroblasts showed about half the uptake capacity of human fibroblasts. The rat fibroblasts resembled the human fibroblasts in the kinetics of uptake of hihg uptake (platelet) enzyme, poor uptake of human placental enzyme, and lack of appreciable turnover of enzyme taken up over 4 days. Heating extracts of rat organs containing added human beta-glucuronidase at 65 degrees selectively inactivated rat enzyme.     

Peripheral vascular versus direct cardiac effects of calcium

Peripheral vascular and direct cardiac effects of calcium chloride were determined in a new animal model, the unanesthetized calf, before and after replacement of its natural heart (NH) with a pneumatically driven artificial heart (AH). Calcium (5 and 10 mg/kg) significantly increased cardiac output (Qt) and reduced systemic vascular resistance (SVR) before and after AH implantation. Increases in Qt in AH calves and reductions in SVR in both NH and AH calves were, however, transient, being present 5 minutes but not 15 minutes after both doses of calcium. Increases in Qt and reductions in SVR were significantly (P less than .05) greater after 10 mg/kg than after 5 mg/kg calcium in NH and AH calves. Both doses of calcium produced greater (P less than .05) increases of Qt in NH than in AH animals but similar reductions in SVR. Pulmonary vascular resitance, heart rate and pulmonary arterial and right atrial pressures were not significantly altered by either dose of calcium in NH or AH calves. Mean aortic pressure was influenced by 10 mg/kg calcium only, being transiently reduced in AH calves and increased in NH animals. Pulmonary shunt (QS/Qt) was increased by both doses of calcium in NH calves but only by 10 mg/kg in AH animals. Correlations of mean change in QS/Qt with mean change in Qt were high both before (r=.99) and after (r=.97) AH implantation. These data demonstrate that calcium significantly reduces SVR in a dose-related manner as well as exerting a positive inotropic effect on the myocardium.     

Reproductive performance and fertility testing in strain 13 and Hartley guinea pigs

A study to test the effects of certain experimental manipulation on the reproductive capacity of male guinea pigs required verifying the fertility of the male guinea pigs before and after manipulation. Methods of testing fertility were evaluated, and normal reproductive data from preexperimental and control groups were tabulated and analyzed. No data from the actual experiments were included. Virgin and proven fertile males were mated with 1 (1:1) or 2 (2:1) virgin or proven fertile females. Inbred (13/N Umm) and conventional (Mfi:CFDH-ML (DH) ) guinea pigs were used. Ninety-five percent of both groups of males were fertile. Eighty-four percent of both groups of females were fertile. Male guinea pigs previously proven fertile had the same subsequent fertility rate as virgin males. Over one-third of the conceptions did not take place during the first estrus cycle (16 da) during which the males and females were mated. Strain 13 and Hartley females had litters of approximately the same size (3.1 vs 3.0), but the neonatal mortality was statistically lower (P less than 0.001) in the Hartley stock (9.3%) than in the Strain 13 guinea pigs (28.4%).