Can rhythm-mediated reward boost learning, memory, and social connection? Perspectives for future research.

Studies of rhythm processing and of reward have progressed separately, with little connection between the two. However, consistent links between rhythm and reward are beginning to surface, with research suggesting that synchronization to rhythm is rewarding, and that this rewarding element may in turn also boost this synchronization. The current mini review shows that the combined study of rhythm and reward can be beneficial to better understand their independent and combined roles across two central aspects of cognition: 1) learning and memory, and 2) social connection and interpersonal synchronization; which have so far been studied largely independently. From this basis, it is discussed how connections between rhythm and reward can be applied to learning and memory and social connection across different populations, taking into account individual differences, clinical populations, human development, and animal research. Future research will need to consider the rewarding nature of rhythm, and that rhythm can in turn boost reward, potentially enhancing other cognitive and social processes.

Nutritional management in renal transplant recipients: A transplant team opportunity to improve graft survival.

AIMS: The nutritional management of renal transplant recipients (RTR) represents a complex problem either because the recovery of renal function is not complete and for the appearance of "unavoidable" metabolic side effects of immunosuppressive drugs. Nevertheless, it remains a neglected problem, whereas an appropriate dietary intervention could favorably affect graft survival. DATA SYNTHESIS: Renal transplantation is associated with steroids and calcineurin inhibitors administration, liberalization of diet after dialysis restrictions, and patients' better quality of life. These factors predispose, from the first months after surgery, to body weight gain, enhanced post transplant diabetes, hyperlipidemia, metabolic syndrome, with negative consequences on graft outcome. Unfortunately, specific guidelines about this topic and nutritional counseling are scarce; moreover, beyond the low adherence of patients to any dietary plan, there is a dangerous underestimation of the problem by physicians, sometimes with inadequate interventions. A prompt and specific nutritional management of RTR can help prevent or minimize these metabolic alterations, mostly when associated with careful and repeated counseling. CONCLUSIONS: A correct nutritional management, possibly tailored to enhance patients' motivation and adherence, represents the best preventive maneuver to increase patients' life and probably improve graft survival, at no cost and with no side effects.

Search for Babesia bovis vaccine candidates.

Babesia bovis is a tick-borne apicomplexan pathogen that remains an important constrain for the development of cattle industries worldwide. Effective control can be achieved by vaccination with live attenuated forms of the parasite, but they have several drawbacks and thus the development of alternative subunit vaccines, either based in recombinant versions of full size proteins or in recombinant or synthetic peptides containing combinations of protective B-cell and T-cell epitopes is needed. Our current strategies for the identification of vaccine candidate antigens include the identification of functionally relevant antigens, bioinformatics, and comparative genomics using the recently sequenced B. bovis genome. These led us to the functional and immunological characterization of members of the VMSA gene family, a group of well conserved putative cysteine and serine proteases, and to the definition of a surface exposed B-cell epitope present in the Merozoite Surface Antigen-2c. Work in progress is focused in defining additional epitopes, and to determine whether they are neutralization-sensitive. These approaches might unravel useful vaccine candidates for B. bovis, and will increase our understanding of the pathogenicity mechanisms of these and related hemoparasites.

Long-term stability of alpha-1-antichymotrypsin complexed form of prostate specific antigen.

PSA complexed with alpha-1-anti-chymotrypsin (cPSA trade mark ) is the moiety in greatest proportion in the serum of men with prostate cancer (CAP). The performance of this analyte has been established primarily in retrospective archival serum. Studies indicate cPSA trade mark provides the specificity enhancement of the free-to-total PSA ratio, yet obviates the need to measure two markers. In the present investigation we sought to establish the stability of cPSA trade mark with long-term storage. Serum from men undergoing ultrasound-guided biopsy was utilized. Serum was assayed soon after collection and 18 months later. All serum was initially aliquotted and stored at -80 degrees C. There was no freeze-thaw. cPSA trade mark was measured utilizing the Bayer Immuno 1 method according to manufacturer's recommendations. The mean (s.d.) PSA was 5.5 (3.8) and 5.6 (3.9) ng/ml at the initial and subsequent testing, respectively. The medians were 4.3 and 4.4 ng/ml, respectively. No significant differences exist between the two determinants (r(2)=1.0, slope=1.01, t-test P=0.9194). These data establish for the first time the long-term stability of cPSA trade mark. Retrospective studies performed on archival material should give meaningful results. Prostate Cancer and Prostatic Diseases (2000) 3, 191-194

Effect of antibody specificity on results of selected digoxin immunoassays among various clinical groups.

We examined the specificity of three automated digoxin immunoassays (Abbott TDxFLx Digoxin II assay, Baxter-Dade Stratus II Digoxin assay, and Ciba Corning ACS Digoxin assay) applied without modification to (a) sera from 229 digoxin-free patients in 12 cohorts associated with nonspecific or endogenous digoxin-like immunoreactive factor (DLIF) interference, and (b) drug-free serum supplemented with the major metabolites and analogs of digoxin. We observed three patterns of apparent digoxin results among the DLIF samples: one common to kidney and liver failure patients, where TDx and Stratus assays showed significant positive results; one common to newborns and cord blood, where only the TDx assay had significant interference; and one from cardiac surgery patients, where the Stratus assay alone showed interference. Of the three assays, the ACS had the least interference from DLIF. The assays also behaved differently with respect to cross-reactivity with digoxin metabolites, digitoxin, and digitoxin metabolites. The ACS assay again had the least analog or metabolite cross-reactivity. The three methods agreed well on digoxin-positive specimens, with a mean bias of <0.15 microgram/L digoxin for each and discrepancies (defined as >3 SD between the assay pairs compared) of only 3-5%.

Cimetidine clearance in the obese.

Six subjects with normal weight (mean weight = 62 kg) and six obese subjects (mean weight = 140 kg) were given a single intravenous cimetidine infusion of 600 mg over 10 to 15 minutes. Both groups of subjects had normal serum creatinine levels and were matched with respect to age, desirable body weight, height, renal function, and sex. Compared with subjects of normal weight, obese subjects had higher cimetidine systemic (1147 and 637 ml/min) and renal (808 and 318 ml/min) clearances. Volume of distribution at steady state was of the same order for the two groups (82 and 84 L), but the t 1/2 was shorter in the obese group (1.2 and 1.9 hr). Obese subjects had lower cimetidine sulfoxide serum concentrations and greater cimetidine sulfoxide renal clearance (856 and 509 ml/min). Cimetidine systemic clearance and cimetidine sulfoxide renal clearance values were of the same order in the two groups when normalized by the value of weight raised to the 0.76 and 0.5 powers. Under the assumptions of an average weight of 70 kg and that average serum concentrations produced by cimetidine, 300 mg iv every 6 hours, are appropriate, people with normal renal function and body weight usually receive 48 mg/day/weight0.76. This same dosage in obese individuals with normal serum creatinine values should result in the same average steady-state serum concentrations. In our obese subjects, the mean cimetidine dose would have been approximately 500 mg iv every 6 hours.

Analysis of digoxin concentrations in serum by fluorescence polarization immunoassay: an evaluation.

The Abbott TDx fluorescence polarization immunoassay was evaluated for the determination of serum digoxin concentrations. Within-assay precision was less than 4% coefficient of variation (CV) for concentrations ranging from 0.64 to 3.75 ng/mL. Between-assay precision was 14.5% CV at 0.75 ng/mL, 5.7% CV at 1.50 ng/mL, and 4.9% CV at 3.48 ng/mL. Sensitivity to 0.2 ng/mL digoxin was confirmed. Correlation of 86 patient specimens assayed by radioimmunoassay (RIA) with the TDx showed the following: correlation coefficient r = 0.94, slope = 0.93, intercept = 0.11, and Sy/x = 0.19. Recovery from serum at concentrations of 0.97 ng/mL and 4.50 ng/mL averaged 98%. No significant interference from lipemia, icteria, or hemolysis was observed. Spironolactone showed no cross-reactivity with the antibody, while digitoxin exhibited significant cross-reactivity. Compared to the RIA procedure, the TDx assay was more rapid, reliable and, in this clinical situation, more cost effective.

Effect of stage of lactation and varying available energy intake on milk production, milk composition, and subsequent tissue enzymic activity.

Twenty-four cows were allotted at parturition to receive one of four rations for 180 days. Rations were regular ad libitum (about 20% crude fiber), concentrate ad libitum (about 10% crude fiber), and restricted to recommended energy intake, and intermediate ration (14% crude fiber) ad libitum. Cows on concentrate consumed less dry matter, fiber and protein than intermediate and regular cows. Cows fed more forage gained more weight, had milk with higher protein and fat content, but were similar in milk production to those fed high concentrate. Fat test decreased to 4 wk in all treatments, and by 8 or 9 wk cows fed concentrate decreased to their lowest fat test. Concentrate restriction enhanced fat test beyond 8 wk. Ruminal propionate was higher and similar for both concentrate groups. Ruminal volatile fatty acids were higher, glucose slightly higher, and blood acetate lower for cows on ad libitum concentrate compared to intermediate. Mammary and adipose tissue from cows in midlactation were assayed for key enzymes of fatty acid synthesis. Activity of 6-phosphogluconate dehydrogenase tended higher for concentrate rations in adipose tissue, but mammary tissue was 21 to 28 times as active. Mammary tissue was 7 to 10 times as active as adipose tissue in fatty acid synthetase with no difference in rations.

Fractionation of plasma triglyceride-rich lipoproteins of the dairy cow: evidence of chylomicron-size particles.

Electron micrographs of bovine triglyceride-rich lipoproteins demonstrated spherical particles with diameters up to 3000 A. Chylomicron-size particles (larger than 750 A) were isolated specifically by rate zonal centrifugation. Subfractionation by rate zonal centrifugation, isopycnic centrifugation, and gel filtration chromatography all indicated a wide range of bovine triglyceride-rich lipoproteins from chylomicrons to very low density lipoproteins. Chemical analysis of subfractions from gel filtration showed changes in the ratio of triglyceride/protein characteristic of chylomicrons versus very low density lipoproteins. Electrophoretic analysis on agarose gels of bovine chylomicrons obtained by centrifugation and gel filtration showed migrating bands similar to very low density lipoproteins, unlike human chylomicrons. Evidence of bovine chylomicrons provides support for the concept of a significant contribution to milk fat from intestinally absorbed lipid in the dairy cow.

Plasma lipid and lipoprotein cholesterol concentrations in adult males consuming normal and high cholesterol diets under controlled conditions.

Twenty-three young adult males were fed diets containing either 400 or 1400 mg of cholesterol per day under controlled conditions for 4 wk. There were minimal differences between the two diets in total protein, carbohydrate, fat, and the P/S fatty acid ratio. In both diets 400 mg of cholesterol was supplied from nonegg food sources; the additional 1000 mg of cholesterol was from four whole eggs. Blood samples were collected after a 12- to 14-h fast at the beginning of the study, weekly throughout the experimental period, and 1 wk after completion of the study. Plasma total cholesterol and triglycerides and high-density, low-density, and very low-density lipoprotein cholesterol levels were measured. No significant differences in plasma total cholesterol, triglycerides, and lipoprotein cholesterol levels were observed between groups at any time. However, plasma cholesterol and cholesterol content of individual lipoproteins varied considerably among the individual subjects fed the high cholesterol diet. The importance of changes in the properties and metabolic activity of individual lipoproteins induced by dietary cholesterol with or without gross changes in the cholesterol levels remains to be determined.

Inhibition of experimental lactational mammary gland growth in the rat with exogenous estrogen and progesterone.

PIP: To determine if the combination of estrogen and progesterone during pregnancy inhibits only the secretory capacity of the mammary gland or if it also inhibits the mitotic activity associated with lactogenesis, 113 virgin female Sprague-Dawley rats were ovariectomized and injected daily for 20 days with 2 mcg of 17beta-estradiol-3 benzoate and 6 mg of progesterone (EP). Then in 4 groups daily, injections were given of either cortisol (C), prolactin (L), growth hormone (G), or a combination of all 3 hormones, for 3 days following the last injection of EP. In another series of 4 groups, the injections of EP were continued along with the above 3 hormones. The structural and functional status of the mammary glands were estimated by measurement of DNA, RNA, and nitrogen content. Details of methods used are given. Only the group treated with C showed the maximum lactational activity with significant elevations in DNA, RNA, and nitrogen content of the mammary glands. When EP was given along with C, G, and L, all hormonally induced increases in DNA, RNA, and nitrogen were inhibited. Results were thought to indicate that, in the rat, levels of EP during normal pregnancy hold milk secretion in abeyance until parturition and also block the particular type of mitotic growth phase associated with early lactation.^ieng

Stimulation of hepatic cholesterol 7alpha-hydroxylase activity by administration of an estrogen (17beta-estradiol-3-benzoate) to female rats.

Adult female rats were given daily subcutaneous injections of 17beta-estradiol-3-benzoate, 25 mug/day for twenty days. Rats were then killed under four different experimental conditions: (1) Fasting, killed in the morning (FM), (2) Non-fasting, killed in the morning (NFM), (3) Fasting, killed at night (FN), and (4) Non-fasting, killed at night (NFN). Estradiol induced a three-fold increase in hepatic cholesterol 7alpha-hydroxylase activity in group FM and a significant increase in group NFN. Although increases in 7alhpa-hydroxylase activity might be associated with lower serum cholesterol levels (by increasing the rate of conversion of cholesterol to bile acids), serum cholesterol concentrations were, in fact, elevated in all rats given estradiol.