X-ray diffraction study of myelin structure in immature and mutant mice

X-ray diffraction patterns were obtained from freshly dissected central and peripheral nerves of quaking, myelin synthesis deficiency (msd), and trembler mutants, as well as immature and adult normal mice. The patterns were compared with respect to strength of myelin diffraction, background scatter level, repeat period, and intensity and linewidth of Bragg reflections. The deficiency of myelin in optic nerves was found to be (in decreasing severity): quaking greater immature greater trembler approximately normal adult; and in sciatic nerves: trembler greater immature greater quaking greater msd approximately normal adult. Repeat periods about 3 A less than that for normal adult sciatic myelin were detected in corresponding nerves from immature, quaking, and trembler mice. In some trembler sciatic nerves a second phase having a 190-200 A period and accounting for about 60% of the total ordered myelin was also evident. Comparison of electron density profiles of membrane units calculated from the repeat periods and diffracted intensities for sciatic myelins indicate structural differences at the molecular level. The main findings are: (1) quaking myelin shows a significant elevation of density in the external protein-water layer between membrane bilayers; (2) the membrane bilayer of immature myelin is approximately equal to 2 A thinner than that for normal adult; (3) the membrane bilayer of the more compact phase in trembler myelin is approximately equal to 5 A thinner than for normal; and (4) the difference in repeat periods for the two phases present in some of the trembler nerves can be accounted for predominantly by distinct membrane bilayer separations at the external boundary.     

Amino acid supplementation of turkey breeder rations

Beltsville Small White turkey hens (60) were randomized into four groups of 15 hens each, weighed and placed in individual laying cages. Immediately after lighting to initiate production, they were placed on a practical type turkey breeder diet calculated to contain 18.26% protein, 2893 Cal. M.E./kg., 3.13% Ca, 0.80% available P, 1.04% arginine, 0.86% lysine, 0.50% methionine & cystine and 0.24% tryptophane. Amino acids were added to this diet as follows: (1) none; (2) 0.1% lysine; (3) 0.05% methionine and (4) 0.1% lysine & 0.05% methionine. Lysine (0.1%) had no effect on reproductive performance when added to the basal ration or to the ration containing additional methionine. Methionine addition (0.05%) improved production significantly (P less than or equal to .005), improved feed efficiency, and increased egg size.     

The expression of normal ventricular repolarization in the body surface distribution of T potentials

Isopotential maps from 120 normal subjects were obtained from 192 simultaneously recorded electrocardiographic leads. Maps were plotted at 1 msec intervals during the QRS and 5 msec intervals during the ST-T deflection. Repetition of QRS features was evident during all but the first few msec of the initial half of serial T maps. This suggests similarities of the normal sequence of ventricular excitation and recovery. Such similarities have been demonstrated by direct studies but are not evident from other electrocardiographic examinations. Serial maps during later portions of the T wave showed decreasing intensity of potentials with little change of body surface locations. This also correlates with an established feature of ventricular repolarization, namely that potential difference boundaries with stable locations are widely distributed during part of that process. Findings suggest isopotential maps show features of ventricular recovery not apparent from less extensive examinations.     

Ascaris suum and Toxocara canis: egg extract antigens in guinea pigs and the macrophage migration inhibition test

Rabbits subjected to chronic blood loss with iron supplementation raised their platelet count and megathrombocyte number 1.7 x and 2.1 x above baseline, respectively. In similarly treated splenectomized animals, no significant response was obtained. When chronic blood loss plasma was injected into recipient animals there was a rise in platelet count and megathrombocyte number of 1.8 x and 3.4 x respectively compared to animals injected with control plasma. In similarly treated splenectomized animals no such rise was obtained; neither was there a rise in platelet count or megathrombocyte number in intact recipient animals when chronic blood loss plasma was obtained from splenectomized animals. It is concluded that the thrombocytosis of chronic blood loss requires the presence of an intact spleen. The data suggest tha presence of a release factor which requires the spleen for its elaboration as well as expression.     

Cystadenocarcinoma of the pancreas presenting as a splenic cyst

A report of a cystadenocarcinoma of the pancreas arising in the spleen from pancreatic heterotopia is presented. The fact that the resected pancreatic tail was microscopically normal and separate from the tumor lends strong support that the tumor arose from pancreatic heterotopia rather than from direct extension or metastasis.     

Zinc sulfate: an adjuvant to wound healing in patients undergoing radical vulvectomy

In an experimental study we tried to find out whether halothane, in addition to its effects on vegetative efferents, has also an influence on catecholamine metabolism of the corresponding brain sections. We studied the effects of halothane in the brain stem of rats on dopamine and norepinephrine contents and on the transformation of L-dopa into dopamine and L-norepinephrine. Anaesthesia with 2 vol% halothane reduced dopamine content by 41.4%, norepinephrine content by 17.8%. These findings could be observed even 3 h after narcosis. Electrophysiological studies show that the central nervous sympathetic activity at rest and after central excitation is clearly reduced during anaesthesia with 2 vol% halothane; 70 min after narcosis it returned to normal. Administration of L-dopa led to an increase of dopamine by 43.5% within 45 min. This transformation of L-dopa into dopamine is not affected by concurrent halothane anaesthesia. There is no increase in norepinephrine after administration of L-dopa. Thus, the effect of halothane on catecholamine metabolism in the brain stem affects the precursors of L-dopa. Halothane is said to inhibit transport of the L-dopa precursor L-tyrosine from plasma to brain tissue. Along with such an inhibition goes the depression of the sympathetic activity. In this respect and obviously on the basis of its position within the catecholamine metabolism, dopamine is more important than norepinephrine.     

Nucleic acids. 16. Orally active derivatives of ara-cytidine

Water-soluble derivatives of ara-cytidine (cytarabine, Cytosar) were prepared and tested for antitumor, immunosuppressive, and antiarthritic activities in animals after oral administration. The compounds tested included the 5'-palmitate, 5'-benzoate, and 5'-adamantoate esters of ara-cytidine, made water soluble by use of their hydrochloride salts of peptidyl derivatives, and two basic 5' esters (5'-nicotinoate and 5'-quinuclidinate) as their hydrochloride salts. Five of the compounds had antitumor activity superior to that found with ara-cytidine itself after oral administration in the L1210 leukemic mouse assay. One of these, 5'-adamantoyl-ara-cytidine hydrochloride, had antitumor activity after oral administration approaching that achieved with parenterally administered ara-cytidine.     

Energetics of isovolumic contractions of the isolated rabbit heart

The significance of bile as an excretory route for cadmium (Cd) was studied in anesthetized, bile-duct-cannulated Sprague-Dawley rats during a 6-hr collection period. Observations were made on bile flow rates, the concentrations of Cd in bile following dietary and parenteral Cd exposure, and the influences of zinc (Zn), selenium (Se), and Cd pretreatments upon the biliary excretion of subsequently administered Cd. The bile flow rates ranged between 1.96 and 2.89 mg/g rat-hr (22 +/- 3 ppb Cd) for normal rats and between 2.68 and 4.09 mg/g rat-hr (58 +/- 6 ppb Cd) for rats fed 100 ppm Cd. Less than 0.1% of the Cd administered subcutaneously at rates ranging from 0.25 to 40 mg/kg rat could be accounted for in bile collected during the 5-hr period following the parenteral Cd injections. Subcutaneous administration of 8 mg Zn/kg rat or 0.5 mg Cd/kg rat on days 1 and 6, respectively, before the postcannulation administration of 1 mg Cd/kg rat caused a significant reduction in the biliary excretion of Cd during the bile collection period. Administering 2 mg Se/kg rat 3 days prior to the postcannulation administration of 1 mg Cd/kg rat caused a significant increase in the biliary excretion of Cd during the bile collection period. The biochemical bases for these observations are believed associated with the type of metal-binding protein induced by the respective pretreatments.     

Inosine 5''-monophosphate dehydrogenase from sarcoma 180 cells-substrate and inhibitor specificity

Navy recruits, all 51 volunteers for a preliminary underwater demolition team (UDT) training program, were followed through 4 weeks of training; 27 men passed and 24 failed the training course. Serum uric acid and serum cholesterol levels, as well as psychological moods data were collected on all volunteers at the start of training and at the end of each of the four training weeks. Men who passed training were compared to those who failed. In addition, these same measures were carried out with a control group of 66 naval recruits. Pre-UDT trainees who passed the program demonstrated high levels of positive moods, early peaks in serum uric acid level, and stable serum cholesterol levels throughout training. These findings supported previous work with successful UDT trainees. Pre-UDT trainees who failed the program demonstrated intermediate levels of positive moods, a midtraining period peak in serum uric acid, and a significant rise in serum cholesterol during the final 2 weeks of the course. The serum cholesterol rise seen during a period shortly prior to failure substantiates previous findings. A comparison group showed low levels of positive moods, an initial peak in serum uric acid, and stable serum cholesterol levels. Two mood scales had siginificant correlations with serum uric acid for only men who passed training. A motivation scale, given at the start of training, correlated with serum uric acid levels for men who failed training.