CHARACTERIZATION OF HUMAN PLATELET VASOPRESSIN RECEPTOR AND THE RELATION BETWEEN VASOPRESSIN-INDUCED PLATELET AGGREGATION AND VASOPRESSIN BINDING TO PLATELETS

Immunoreactive AVP was found to be much higher in platelets than in platelet-free plasma (PFP) in normal subjects (12.8 +/- 6.3 versus 1.7 +/- 0.8 fmol/ml). AVP levels in PFP were appreciably elevated in parallel with the elevation of plasma osmolality induced by the acute osmotic stimulation, while the AVP levels in platelets did not change before and after the stimulation. Binding studies on intact platelets demonstrated specific binding sites for [3H]AVP. The specific binding was time, temperature and concentration-dependent, saturable and reversible, with the maximal binding capacity (Bmax) of 169.9 +/- 14.4 sites/platelet and affinity of 4.84 +/- 1.15 x 10(8)M-1. The affinity constants for unlabelled AVP, lysine vasopressin (LVP), oxytocin (OT) and dDAVP were 9.0, 8.5, 7.4 and 6.6, respectively, and the inhibition constant for d(CH2)5Tyr(Me)AVP (V1-antagonist) was 7.7. There was a highly significant correlation between the affinity constants of AVP analogues and their relative vasopressor activities in vivo, whereas no such correlation was found between the affinity constants and antidiuretic activities. AVP caused platelet aggregation with the maximal aggregation of 48.0 +/- 25.1% at 230 nM of AVP. A significant correlation was observed between the maximal percentage aggregation and Bmax of [3H]AVP to intact platelets. These results suggest that the platelet vasopressin receptor belongs to the V1 vascular subtype and mediates platelet aggregation.     

INCREASE IN BILIRUBIN BINDING TO ALBUMIN WITH CORRECTION OF NEONATAL ACIDOSIS

Abstract. Twenty-six serial measurements of free bilirubin concentration and apparent association constant of bilirubin for albumin (Ka) at a bilirubin: albumin molar ratio of 0.8 were performed and compared with baseline values in 11 newborn infants with acidosis before treatment and during recovery from acidosis. When arterial pH was corrected from 7.12±0.02 (Mean±S.E.M.) to 7.34±0.02, there was a significant decrease in serum free bilirubin concentration and a significant increase in the Ka at molar ratio 0.8. The data offer in vivo evidence that correction of acidosis in the neonate results in an improvement of the apparent bilirubin binding affinity of albumin.     

A variant protein in human parotid saliva detected by SDS polyacrylamide ǵel electrophoresis and its inheritance

In 218 parotid saliva samples collected at random from a Japanese population, two phenotypes were observed by SDS polyacrylamide gel electrophoresis. Inheritance was controlled by a dominant allele at an autosomal locus. The frequencies of the genes determining these phenotypes were for the Japanese population studied: Ph+ = 0.026 +/- 0.008, Ph- = 0.974 +/- 0.008.     

INHIBITORS AND PROACTIVATORS OF FIBRINOLYSIS IN HUMAN EPIDERMIS

Summary.— Normal human epidermis was homogenized and separated into "heavy mitochondrial", "light mitochondrial", "microsomal" and "soluble" fractions by differential centrifugation in the cold. The homogenate and the subcellular fractions were investigated on fibrin plates for their fibrinolytic activity, their inhibitor activity against urokinase, and proactivator activity.
No direct fibrinolytic activity was demonstrated in the homogenate or the suhcellular fractions, but they showed inhibitory activity against urokinase and strong fibrinolytic activity following streptokinase treatment. Both activities were predominant in the soluble fraction. Weak activity was also found in particulate fractions. The distribution pattern of both activities in subcellular fractions was very similar. The possible existence of a complex of proactivator and inhibitor in the epidermis is discussed.     

An outbreak of group B streptococcus infection in a neonatal nursery and subsequent trial for prophylaxis of nosocomial transmission

An outbreak of sepsis and meningitis caused by group B streptococcus occurred in three very low birthweight infants. To prevent further nosocomial transmission, immune globulin and ampicillin sodium were administered intravenously to other very low birthweight infants. After this prophylaxis, no other infants were involved in this outbreak. Immuno- and chemoprophylaxis may be considered as procedures to prevent nosocomial infection for very low birthweight infants.     

Multiple Endocrine Neoplasia Type 2b (I) Report of a Case

This is a case report of a 14-year-old girl with multiple endocrineneoplasia (MEN) type 2b. The patient had mucosal neuromas, medullarycarcinoma of the thyroid, bumpy lips, hypertrophied cornealnerves, absent flare response following intradermal histamineinjection, high arched palate, oligodontia, pes cavus and polypoidlesions in the colon. Urinary catecholamines were normal andthe patient's blood pressure did not rise abnormally after glucagonor histamine infusions. The left adrenal gland was not visualizedon examination by adrenal scintiscanning, but by computed tomographyit was enlarged. Nerve growth factor (NGF) was normal in theserum. Extensive studies failed to identify other family memberswith MEN. This patient seems to be a sporadic case.     

Double Adenocarcinoma in Barrett's Esophagus: A Case Report

At the National Cancer Center Hospital in Tokyo, a patient withBarrett's esophagus developed double adenocarcinoma of the esophagus.One carcinoma was located in the midesophagus and the otherjust above the anatomic cardia. Esophagoscopic examination withbiopsy revealed two carcinomas surrounded with columnar epitheliumand ectopic islets of gastric mucosa situated in the postcricoidregion. There was no ulcer or stricture in the esophagus. Thepatient received subtotal esophagectomy and survived the operation.Microscopically, depth of invasion of the proximal cancer wasto the proper muscle, and that of the distal one was to thesubmucosal layer. There was metastasis to two lymph nodes. Therewas no sign of inflammation or ulcer in the esophagus.     

Influence of Mobile Magnetic Resonance Imaging on Implanted Pacemakers

KISHI, R., et al.: Influence of Mobile Magnetic Resonance Imaging on Implanted Pacemakers. Purpose: Mobile magnetic resonance imaging (MRI) systems will be widely used in Japan. When traveling, mobile MRI generate alternating electromagnetic waves which may cause electromagnetic interference (EMI). This study was designed to determine whether this may influence the function of implanted pacemakers (PM). Methods and Results: The influence of the static magnetic fields was tested in the first method using a PM-human model (Phantom). Magnetic force was simultaneously measured. The PM was switched to the magnet mode within 90 cm from the vehicle, where the magnetic force was = 2 mT. In the second method, six phantoms were placed on the side of the road, facing in three different directions in X-Y-Z axis orientations, at 1.3 m and 2.0 m above the ground. The mobile MRI passed by at a distance of 1 m from the phantoms at the speed of 20 or 40 km/h. In these experiments, magnet mode switch of the PM was observed for 2 seconds when the vehicle passed close to the phantoms, though no electrical noise was recorded. Conclusion: Mobile MRI vehicles can switch a PM to magnet mode when the distance between patient and vehicle is <90 cm, regardless of whether the vehicle is moving or at a stop. Patients with implanted PM should not approach within <1 m of a mobile MRI. No other EMI-induced PM dysfunction was detected. (PACE 2003; 26[Pt. II]:527–529)     

Relationship of decrease in fecundity with advancing age to structural changes in mouse endometrium

The aim of this study was to determine whether a relationship exists between decrease in fecundity and structural changes in the antimesometrial endometrium of the mouse. Fecundity was calculated as the number of animals showing a placental sign/number of copulated animals ×100 (%). Structural changes in the endometrium were examined by electron microscopy. A negative correlation between age and fecundity was found. Fecundity was 50% at 7 mo of age. At this age, amorphous material appeared in the region between the basement membrane deep to the luminal epithelium and the subepithelial cells. This material was sometimes attached to the basement membrane. It increased in amount with advancing age, as fecundity decreased. The structure of the uterine luminal epithelial cells did not alter with age. The results indicated that decrease in fecundity with advancing age is correlated with the appearance of amorphous material beneath the basal lamina of the endometrial epithelium. It is suggested that this could impair communication between the luminal epithelium and the endometrial stroma, which plays an important role in implantation.