Control of feeding and sexual behaviors by neuropeptide Y: physiological implications

Recent evidence suggests that a variety of hypothalamic neuropeptides may mediate interneuronal communication to coordinate diverse neuroendocrine and behavioral functions. In this work, we describe the effects of neuropeptide Y (NPY) on feeding and sexual behaviors. We observed that central administration of bolus NPY stimulated a robust, dose-related feeding response in satiated male and female rats. Continuous NPY receptor activation also evoked dose-related, intermittent feeding in a manner normally observed during nocturnal feeding. It appears that the paraventricular nucleus in the hypothalamus may be the primary site of NPY action because the anticipated reciprocal changes in NPY concentrations, in response to food deprivation followed by ad libitum food intake, occurred only in this site. Additional findings revealed that NPY-induced feeding may follow either substantial reduction or complete restraint of an inhibitory influence on feeding mediated by alpha 2-adrenoreceptor systems in satiated rats. Further, NPY was found to suppress male and female sexual behaviors. The suppressive effects on sexual behavior were apparent prior to or at the time of the onset of feeding after NPY administration. These observations may provide a neurochemical basis for clinical and animal studies on disorders of feeding associated with diminished reproductive functions.     

Tumor vascular signals in renal masses: detection with Doppler US

The vascularity of 49 renal masses (26 malignant and 23 benign lesions) was investigated with duplex Doppler ultrasound. Doppler signals obtained at the margins of renal masses were defined as "tumor signals" when the Doppler-shifted frequency of the lesion exceeded the frequency shift in the ipsilateral main renal artery. These exceeded 2.5 kHz with a 3-MHz insonating frequency. Among the 26 renal masses that subsequently proved to be malignant, tumor signals were obtained in 15 of 18 (83%) untreated renal cell carcinomas, in three of four Wilms tumors, and in two patients with metastases to the kidney, but not in the one patient with lymphoma. None of the 23 benign renal masses demonstrated tumor signals. Tumor vascularity in malignant lesions gives rise to abnormal, high-velocity, Doppler-shifted signals that can help in the differential diagnosis of renal masses.     

Structure-function analysis of stimulation of food intake by neuropeptide Y: effects of receptor agonists.

Neuropeptide Y (NPY) is a potent natural orexigenic signal in the rat. In this study, we have compared the effects of several COOH-terminal fragments of NPY and NPY receptor agonists on cumulative food intake in male rats. Rats were implanted with permanent cannulae either into the third cerebroventricle or paraventricular nucleus (PVN). NPY1-36 and various COOH-terminal fragments of NPY, two agonist analogues [Leu31, Pro34]NPY and NPY 1-4-Aca (epsilon-amino-caproic acid)-25-36, were administered intracerebroventricularly (ICV) or directly into the PVN, and the cumulative 2-h food intake response was compared. We observed that peptides that were effective by ICV were also effective when administered into the PVN, but smaller amounts of the peptides were required after PVN injection to evoke an equivalent food intake response. Injection of NPY1-36 induced a dose-dependent increment in food intake. Surprisingly, deletion of NH2-terminal tyrosine residue did not adversely affect feeding behavior. In fact, NPY2-36 was consistently more effective than NPY1-36; the enhancement in feeding by NPY2-36 was dose-related and was higher than evoked by NPY1-36 at each dose tested. Further serial deletion of aminoacids at NH2-terminal resulted in complete loss of activity. In addition, NPY agonist analogue, NPY 1-4-Aca-25-36, failed to stimulate feeding. However, NPY Y1 receptor agonist, [Leu31, Pro34]NPY, but not Y2 receptor agonist, NPY13-36, stimulated feeding.(ABSTRACT TRUNCATED AT 250 WORDS)     

Specificity of the monoclonal anti-I antibody (Hy)

In previous work we found that a monoclonal cold hemagglutinin from patient Hy strongly bound antigens contained in stage IV breast cancer sera. To infer the chemical structure of the antigens expressed in the cancer sera, we studied the specificity of the antibody (Hy). The antibody (Hy) had I specificity, based on agglutination scores with adult and cord red blood cells. The binding of the antibody to synthetic and milk oligosaccharides was determined using a solid phase enzyme immunoassay (EIA). The anti-I antibody (Hy) strongly bound LacNAc0-Me, LacNAc1----6Gal, LacNAc1----6 (LacNAc1----3)Gal, LacNAc-1----6 alpha GalNAc, LacNAc1----3LacNAc, and LacNAc, 0.05, 0.06, 0.09, 0.22, 0.35 and 0.75 mM giving 50% inhibition, respectively. The anti-I antibody (Hy), similar to the anti-I antibody (Ma), strongly bound LacNAc1----6Gal, but it differed from the anti-I antibody (Ma) in its cross-reactivity with the i sequence. The anti-I antibody (Hy) showed similar reactivities as the hybridoma monoclonal antibodies M18 and M39 with LacNAc1----6Gal and with the i-active sequence. The EIA procedure is a useful alternative to either radioimmunoassay or immunoprecipitation method in the study of anti-I,i specificities.     

Hemostatic parameters in newborn--II. Sequential study during the first four weeks of life

A sequential study of kaolin cephalin clotting time (KCCT), prothrombin time (PT), thrombin time (TT), plasma fibrinogen and serum FDP was conducted during the first four weeks of life on term and preterm babies. A "physiological dip" of PT and TT was noted inappropriate for gestational age (AGA) babies both term and preterm; in case of KCCT, the dip was significant in term AGA babies only. At the end of four weeks, PT and TT had moderately improved in term babies but showed little improvement in preterm ones; KCCT reached almost an adult value in all babies except in preterm AGA and term LGA (large for gestational age) ones. Plasma fibrinogen showed no "physiological dip" and reached adult level in two to four weeks. Serum FDP levels were appreciably raised in preterm AGA babies only at birth and there too normalised by 72 h.