Sonographic evaluation of gallbladder kinetics: in vitro and in vivo comparison of different methods to assess gallbladder emptying.

In an in vitro study, 10 gallbladders of adult pigs and 6 gallbladders of lambs, all removed immediately after slaughtering, were stimulated in a water bath by electric means to induce active contraction. Gallbladder emptying was followed by ultrasonography employing five measurement procedures: (1) gallbladder width, (2) longitudinal planimetry, (3) transverse planimetry, (4) ellipsoid method, and (5) sum of cylinders method. In an in vivo investigation, gallbladder emptying of 30 volunteers (12 healthy subjects, 18 diabetics) was evaluated in the same way after ingestion of a fatty meal. Gallbladder width was found to be unsuitable to estimate the decrease in gallbladder volume due to a nonlinear relation of the parameters. Longitudinal planimetry tended to be less valid than transverse planimetry in assessing gallbladder volume reduction. The most valid estimation of gallbladder volume decreases was obtained by the two three-dimensional procedures. However, in neither in vitro nor in vivo could a significant difference between the sum of cylinders method and the ellipsoid method in determining relative volume reduction be established. We conclude that a three-dimensional measurement procedure should be used for valid assessments of gallbladder motility. However, according to our data there is no advantage in using the time-consuming sum of cylinders method compared to the simple ellipsoid method.     

CNQX, a new non-NMDA receptor antagonist, reduces spike wave discharges in the WAG/Rij rat model of absence epilepsy.

The effects on seizures, EEG and behavior of the non-NMDA receptor antagonist CNQX (6-cyano-7-nitroquinoxaline-2,3-dione), were studied in the WAG/Rij rat with absence epilepsy. Intracerebroventricular injections (10, 50, and 100 nmol/5 microliters CNQX) showed that CNQX decreases the number of spike wave discharges in a dose-dependent way. Coinjection of CNQX (100 nmol/5 microliters) and AMPA (0.1 pmol/5 microliters), kainic acid (0.01 nmol/5 microliters) or NMDA (50 pmol/5 microliters) attenuated the CNQX response, indicating that CNQX acts on both non-NMDA and NMDA receptors. The observed effects appear to be specific manipulations of the epilepsy not mediated by behavioral changes.     

Production of Co and Co via proton induced reactions on highly enriched Ni

⁵⁵Co and ⁵⁷Co were produced via (p, α) and (p, 2p) reactions, respectively, on highly enriched ⁵⁸Ni. Thin deposits of ⁵⁸Ni on Cu backing, obtained electrolytically, were irradiated using a slanting beam. The separation of radiocobalt and the recovery of the enriched target material were effected via anion-exchange chromatography.     

Collateral vessel regression in a child with primary congenital glaucoma.

The presence of collateral vessels in a young child with glaucoma is rare. The authors describe a case of collateral vessel regression with intraocular pressure reduction in a child with primary congenital glaucoma. Six months following 180 degrees goniotomies in each eye, the intraocular pressure was reduced, dilation of the retinal arteries and veins resolved, and collateral vessels in both eyes regressed. Intraocular pressure reduction may lead to the regression of collateral vessels in children with primary congenital glaucoma.     

Myocardial metabolism and adaptation during extreme hemodilution in humans after coronary revascularization.

OBJECTIVE: This study was designed to evaluate the oxygen transport adjustments and myocardial metabolic adaptation that occurs with different levels of hemodilution during normothermia after cardiopulmonary bypass. DESIGN: Prospective, nonrandomized study. SETTING: Operating room in a university hospital. PATIENTS: Eight patients with ejection fractions (> 40%) undergoing elective coronary artery bypass grafting. METHODS: Before the institution of cardiopulmonary bypass, blood was withdrawn from patients to a target hematocrit of 15%. After coronary artery bypass grafting, a catheter was inserted directly into the coronary sinus. After the patients were rewarmed to 37 degrees C, they were weaned from cardiopulmonary bypass. Hemodynamic indices were measured, as well as measurements of myocardial oxygen consumption (VO2) and myocardial metabolism (lactate extraction and coronary sinus hypoxanthine). Measurements were made at three different hematocrit values: 15%, 20%, and 25%. Hematocrit was increased by autologous blood transfusion. MEASUREMENTS AND MAIN RESULTS: The three levels of hemodilution (hematocrit: 17.4 +/- 3.4%; 23.0 +/- 3.7%; 27.8 +/- 4.8%) were significantly different from baseline (hematocrit 37 +/- 2.6%; p < .05). Oxygen delivery, which increased with autologous transfusion, exceeded 350 mL/min/m2 at each level of dilution. The myocardial VO2 increased significantly after autologous transfusion compared with the most dilute condition (7.0 +/- 3.7 mL/min at hematocrit 17.4% vs. 11.2 +/- 4.8 mL/min at hematocrit 23.0% and 12.4 +/- 4.0 mL/min at hematocrit 27.8%). This transfusion-induced increase was also true of myocardial oxygen extraction. Lactate extraction and hypoxanthine release were normal and unchanged at each level of hemodilution. Systemic oxygen extraction ratio increased with hemodilution and decreased with autologous transfusion. CONCLUSIONS: Hemodilution to a hematocrit of approximately 15% is tolerated in anesthetized humans after coronary artery bypass surgery. There was no evidence of myocardial ischemia, as demonstrated by absence of S-T depression on the electrocardiogram, lactate extraction, or hypoxanthine release. In selected patients, postoperative transfusion may be based on systemic physiologic end-points, such as oxygen extraction ratio, rather than set hematocrit values.     

Excitation functions of (alpha,xn) reactions on (nat)Rb and (nat)Sr from threshold up to 26 MeV: possibility of production of (87)Y, (88)Y and (89)Zr.

Excitation functions were measured by the stacked-foil technique for (nat)Rb(alpha,xn)(87m,87m+g,88)Y and (nat)Sr(alpha,xn)(86,88,89)Zr reactions from their respective thresholds up to 26 MeV. The samples for irradiation were prepared by sedimentation and pellet pressing techniques. The measured data were compared with those available in the literature. From the excitation functions, integral yields of the products were calculated. The suitable energy ranges for the production of (87)Y and (88)Y via (nat)Rb(alpha,xn) processes and of (89)Zr via the (nat)Sr(alpha,xn) process are E(alpha)=26-->20 MeV, E(alpha)=26-->5 MeV and E(alpha)=20-->8.5 MeV, respectively. The respective yields amount to 8.2, 0.08 and 0.9 MBq/microA h. Production of (88)Y is feasible if a waiting time of about 2 months is allowed to let the impurities decay out. Also, (87)Y can be produced with a relatively low impurity of (88)Y. The yields of both (88)Y and (87)Y via the present routes are, however, appreciably lower than those via the (nat)Sr(p,xn) processes. There is a possibility to produce (89)Zr via the alpha-particle irradiation of (nat)Sr. The yield is rather low but would be considerably increased if enriched (86)Sr would be used as target material. The radionuclidic impurity levels in all the three products are discussed.     

Confidants' feedback and traumatic life events

One hundred six undergraduate (83 women and 23 men) completed surveys concerning their most traumatic life event, the feedback they received following their disclosure of the event to others, and how they felt after the disclosure. Results indicated that the better they felt after disclosure, the less disturbed they were by thoughts of the event at the time of the study. In addition, the more personal the trauma was, the worse they felt after their disclosure, and the more disturbed they were about the trauma. However, no significant relation existed between the positivity (e.g., supportiveness) of their confidant's feedback and their present degree of disturbance. Implications for understanding the complex relation between confiding traumatic events and resolving feelings surrounding those events were discussed.     

Decreased prefrontal 5-HT2A receptor binding in subjects at enhanced risk for schizophrenia

The brain serotonin-2A receptor (5-HT_2AR) has been implicated in both the pathology of schizophrenia and the therapeutic action of atypical antipsychotics. However, little is known about the 5-HT_2AR status before the onset of schizophrenia and before the exposure to antipsychotics. We used [¹⁸F] altanserin and positron emission tomography (PET) in a pilot study of 6 individuals suspected to be at elevated risk for schizophrenia and seven age-matched controls to test the hypothesis that regional 5-HT_2AR binding is altered in the prodromal stages of schizophrenia. Distribution volume ratios (DVRs) as a proxy for 5-HT_2AR availability were significantly reduced in prefrontal cortex regions of at-risk subjects, implicating early abnormalities of serotonergic neurotransmission that antecede the onset of schizophrenia.     

Lesser response to angiotensin-converting-enzyme inhibitor therapy in black as compared with white patients with left ventricular dysfunction

BACKGROUND: Black patients with heart failure have a poorer prognosis than white patients, a difference that has not been adequately explained. Whether racial differences in the response to drug treatment contribute to differences in outcome is unclear. To address this issue, we pooled and analyzed data from the Studies of Left Ventricular Dysfunction (SOLVD) prevention and treatment trials, two large, randomized trials comparing enalapril with placebo in patients with left ventricular dysfunction. METHODS: We used a matched-cohort design in which up to four white patients were matched with each black patient according to trial, treatment assignment, sex, left ventricular ejection fraction, and age. A total of 1196 white patients (580 from the prevention trial and 616 from the treatment trial) were matched with 800 black patients (404 from the prevention trial and 396 from the treatment trial). The average duration of follow-up was 35 months in the prevention trial and 33 months in the treatment trial. RESULTS: The black patients and the matched white patients had similar demographic and clinical characteristics, but the black patients had higher rates of death from any cause (12.2 vs. 9.7 per 100 person-years) and of hospitalization for heart failure (13.2 vs. 7.7 per 100 person-years). Despite similar doses of drug in the two groups, enalapril therapy, as compared with placebo, was associated with a 44 percent reduction (95 percent confidence interval, 27 to 57 percent) in the risk of hospitalization for heart failure among the white patients (P<0.001) but with no significant reduction among black patients (P=0.74). At one year, enalapril therapy was associated with significant reductions from base line in systolic blood pressure (by a mean [+/-SD] of 5.0+/-17.1 mm Hg) and diastolic blood pressure (3.6+/-10.6 mm Hg) among the white patients, but not among the black patients. No significant change in the risk of death was observed in association with enalapril therapy in either group. CONCLUSIONS: Enalapril therapy is associated with a significant reduction in the risk of hospitalization for heart failure among white patients with left ventricular dysfunction, but not among similar black patients. This finding underscores the need for additional research on the efficacy of therapies for heart failure in black patients.     

Mental and physical effort affect vigilance differently.

Both physical and mental effort are thought to affect vigilance. Mental effort is known for its vigilance declining effects, but the effects of physical effort are less clear. This study investigated whether these two forms of effort affect the EEG and subjective alertness differently. Participants performed a physical task and were subsequently presented with a mental task, or vice versa. Mental effort decreased subjective alertness and increased theta power in the EEG. Both results suggest a vigilance decline. Physical effort, however, increased subjective alertness and alpha and beta1 power in the EEG. These findings point towards an increase in vigilance. Beta2 power was reduced after physical effort, which may reflect a decrease in active cognitive processing. No transfer effects were found between the effort conditions, suggesting that the effects of mental and physical effort are distinct. It is concluded that mental effort decreases vigilance, whereas physical effort increases vigilance without improving subsequent task performance.