Spinal dysraphisms.

The practitioner is faced with the challenge of identifying occult presentations of spinal dysraphism and providing follow-up treatment of foot and leg deformities. The initial symptoms of a spinal dysraphic condition may be subtle and involve the lower extremity. An increased understanding of spinal dysraphism will encourage early diagnosis and prompt effective treatment.

Studies on experimentally induced hyperphenylalaninemia.

The administration of several compounds that can increase plasma phenylalanine levels and/or inhibit phenylalanine hydroxylase in rats was studied in order to determine their usefulness in inducing a phenylketonuria-like state. The results of this investigation revealed that 4.5 microns/10 g p-chlorophenylalanine is more effective than L-phenylalanine, alpha-methylphenylalanine, trimethoprim, Bactrim and Septra, since the former compound produced both adequate hyperphenylalaninemia and marked inhibition of hepatic phenylalanine hydroxylase activity.

Progressive enzyme changes within anatomically defined segments of rabbit nephron: demonstration with a new technique.

The kidney is an extremely heterogeneous organ, with morphological, physiological, and metabolic changes occurring from segment to segment along each nephron. To determine the heterogeneity that might exist within discrete anatomical segments of rabbit nephron, we developed a technique for making quantitative enzyme assays in serial samples, about 100 micron long, along identified segments of the nephron. Results for three enzymes in proximal convoluted and straight tubules show that adenylate kinase, an enzyme of high-energy phosphate metabolism, gradually decreases along the S1 and S2 segments of the proximal tubule, with no abrupt changes.

Transfection of mammalian cells with plasmid DNA by scrape loading and sonication loading.

Scrape loading and sonication loading are two recently described methods of introducing macromolecules into living cells. We have tested the efficacy of these methods for transfection of mammalian cells with exogenous DNA, using selection systems based either on resistance to the drug G418 (Geneticin) or on acquisition of the ability to utilize the salvage pathway of pyrimidine biosynthesis. These loading methods can be employed to generate cell lines that express the gene product of the transfected DNA molecules both transiently and stably.

Lymphocyte membrane sodium-proton exchange in spontaneously hypertensive rats.

The sodium-proton exchange activity was determined in lymphocytes of spontaneously hypertensive rats (SHR), normotensive Wistar-Kyoto rats (WKY), and domestic Wistar rats. Uptake of sodium was determined by measuring the osmotic swelling of lymphocytes after activation of the exchanger by suspension of the cells in sodium propionate and consequent intracellular acidification by the permeant weak acid. Fractional swelling (mean +/- SEM) in 16 SHR and 16 WKY was 0.

Relationships among maternal and fetal amino acid blood concentrations and amniotic fluid amino acid levels in pregnant rhesus monkeys.

This study was designed to explore relationships among maternal and fetal amino acid blood concentrations and amniotic fluid amino acid levels in pregnant rhesus monkeys. Although there was no constant pattern for all amino acids in the three body fluids, we observed specific patterns for most neutral amino acids, imino acids, and acidic amino acids relative to their concentrations in maternal blood, fetal blood, and amniotic fluid. Moreover, there was no correlation between fetal phenylalanine blood levels and phenylalanine concentrations in amniotic fluid indicating that amniotic fluid phenylalanine levels would not be useful to monitor fetal phenylalanine blood concentrations during pregnancy.

Fetomaternal placental transfer mechanisms of aromatic amino acids in Macaca mulatta.

We investigated aromatic amino acid transfer mechanisms from fetus to mother in third-trimester pregnancies in rhesus monkeys after the administration of radioactive phenylalanine to the fetal circulation. The results indicated that fetomaternal transfer takes place mainly by facilitated diffusion via specific membrane carriers. This mechanism might participate in regulating amino acid concentrations in the fetus.

Biological and behavioural assessments of young rhesus monkeys after intrauterine exposure to high phenylalanine concentrations.

Nineteen pregnant Macaca mulatta were fed a special diet throughout the gestational period in an attempt to render them hyperphenylalaninaemic. Group C (control group) received a regular diet, group Lo was given a 'low' phenylalanine diet, group Me a 'median' phenylalanine diet, and group Hi a 'high' phenylalanine diet. Nearly all monkeys had an uncomplicated pregnancy and an uneventful delivery.

Erythrocyte membrane transport in hypertensive humans and rats. Effect of sodium depletion and excess.

Sodium transport by erythrocyte membranes was studied in hypertensive and normotensive humans and in spontaneously hypertensive rats (SHR) and normotensive Wistar-Kyoto rats (WKY). The rate constants of sodium efflux were increased in both hypertensive humans and rats, and this increase was due mostly to an increase in the ouabain-resistant component of efflux. Both the furosemide-sensitive and furosemide-resistant components of efflux were increased.

Adolescent development in males with Down syndrome.

We investigated growth features, development of primary and secondary sex characteristics, and specified pituitary and testicular hormone levels in 46 male adolescents and young adults with Down syndrome. Their mean height age was significantly less than and their mean bone age was slightly more than their chronological age. The subjects' secondary sex characteristics followed the same developmental pattern noted in youngsters without Down syndrome.

Essential elements of quality control.

The components of quality control in the pharmaceutical industry are discussed as they apply to hospital pharmacy admixture services. The pharmaceutical industry complies with the FDA's Current Good Manufacturing Practices, which require manufacturers to have written procedures for ensuring sterility and nonpyrogenicity of injectable products. Because FDA specifies only what outcome measures must be assessed (rather than specific means of assessment), pharmaceutical companies have developed a multiplicity of quality-control systems.

Bioactive cardiac substances: potent vasorelaxant activity in mammalian atria.

Mammalian atrial extracts possess natriuretic and diuretic activity. In experiments reported here it was found that atrial, but not ventricular, extract also causes relaxation of isolated vascular and nonvascular smooth muscle preparations. The smooth muscle relaxant activity of atrial extract was heat-stable and concentration-dependent and could be destroyed with protease.

Primary aortoduodenal fistula following radiotherapy.

Primary aortoduodenal fistula is a rare condition. Common causes include atherosclerosis, leading to formation of an aortic aneurysm (most common); syphilis; carcinoma of the pancreas; trauma; tuberculosis, and myocosis. Presented herein is the recognition and successful treatment of what appears to be the first patient with a primary aortoduodenal fistula following paraaortic radiotherapy.

Placental transfer of phenylalanine in Macaca mulatta and Macaca fascicularis.

We investigated placental transport mechanisms of phenylalanine in Macaca mulatta and Macaca fascicularis. In the beginning of the third trimester we administered i.v.

Placental transfer of aromatic amino acids in non-human primates.

Macaca fascicularis (crab-eating monkeys) underwent an operative procedure at 120 to 130 days of pregnancy that allowed fetal blood sampling. During subsequent experiments L-phenylalanine and p-chlorophenylalanine were injected into the maternal circulation. Blood obtained from mother and fetus revealed that phenylalanine is actively transported across the placenta and hence is markedly increased in the fetus if the maternal blood phenylalanine concentration is below the "saturation" level of 1.

Distribution of enzymes of adenylate and guanylate nucleotide metabolism in rat nephron.

In a previous study of discrete segments of rat nephron, we reported the levels of high-energy adenylate and guanylate phosphates to be highest in the distal straight and convoluted tubules. Those findings stimulated the study of the distribution of seven enzymes involved in the following metabolic pathways of these nucleotides [Formula: see text]. The patterns of distribution of enzymes in each pathway differed greatly.

A study of placental transfer mechanisms in nonhuman primates using [14C]phenylalanine.

Placental transfer mechanisms were investigated in pregnant Macaca Fascicularis and Macaca mulatta during the gestational age of 120 to 130 days. These primates underwent an operative procedure that allowed continuous fetal blood sampling. The administration of [14C]phenylalanine into the maternal circulation revealed a significant increase of radioactive material in the fetal circulation, indicating an active placental transport mechanism unidirectional to the fetus.

Renal lesions and proteinuria in the spontaneously hypertensive rat made normotensive by treatment.

Spontaneously hypertensive rats (SHR) (N = 40) were maintained at normal blood pressure to the age of 100 weeks by treatment (reserpine, hydralazine, and chlorothiazide) beginning at intervals in groups of eight, from the 5th to 45th week. Mortality rates, patterns of proteinuria, and glomerular and arteriolar pathology were compared with that of treated and untreated normotensive Wistar-Kyoto (WKY) controls matched for age (N = 39) and untreated SHR's (N = 26). Treatment clearly prolongs life in SHR's, the mortality rate for untreated being 100% at 75 weeks versus no deaths at that age among 24 SHR's treated before 20th week.

Stability of frozen solutions of cefamandole nafate.

The chemical, microbiological and visual stability of frozen solutions of cefamandole nafate was studied. Solutions of cefamandole nafate were prepared by diluting 1 g of drug with 3 ml of Water for Injection, USP, or 0.9% Sodium Chloride Injection, USP, or 5% Dextrose Injection, USP (i.