Preparation of both DNA and RNA for hybridization analysis from limiting quantities of lymphoid cells

This report describes a method for preparing both DNA and RNA simultaneously from as few as 5 X 10(5) lymphoid cells. The method is suitable for cultured cells or any tissue from which a cell suspension can be prepared and for the small samples of purified cells obtained by fluorescence activated cell sorting. Cells are lysed with Nonidet P-40 and the nuclear and cytoplasmic fractions separated by centrifugation. Nuclei are embedded in low-gelling-temperature agarose and the proteinase K and restriction enzyme digestions performed whilst the DNA is immobilized in this form. Total RNA is prepared from the cytoplasmic fraction. This method is simple but reliable and is therefore particularly useful for preparing and analyzing the DNA and RNA from multiple samples when material is limited.

Constraints on spacing between transcription factor binding sites in a simple adenovirus promoter

The adenovirus 2 E1B transcription unit has an extremely simple promoter consisting of a TATA box and a closely situated GC box. The interaction between the TATA box and the GC box was analyzed using insertion mutations which expand the distance between the two elements. We observed that the E1B promoter has an unusually rigid architecture. When the GC box, which is a binding site for transcription factor Sp1, was separated further from the TATA box than in the wild-type promoter, in vivo transcription quickly diminished to a level comparable to the elimination of the Sp1 site. Yet all the insertion mutants bound Sp1 factor in vitro with an affinity approximately equal to that of the wild-type promoter. From these results, we argue that Sp1 binding alone is not sufficient to stimulate transcription. The increased distance might disrupt direct contacts between Sp1 and transcription factors bound at the TATA box, contacts required for transcription stimulation by Sp1. The insertion mutations do not interfere with the transcription activation process mediated by the adenovirus large E1A protein or the pseudorabies virus immediate early protein.

Contribution of the urea appearance rate to diuretic-induced azotemia in the rat

Studies were performed to evaluate the contribution of the urea appearance rate to the elevated plasma urea concentration found during diuretic-induced sodium depletion. Negative sodium balance of -1162 + 29 microEq/100 g body wt was induced over a four day period by the administration of furosemide, 20 to 30 mg/kg/d i.p., to rats ingesting a sodium free diet. When compared with sodium replete controls, sodium depletion significantly increased the plasma urea concentration (65.0 +/- 3.1 vs. 26.4 +/- 1.1 mg/dl) through both an increase in the urea appearance rate (160 +/- 5.2 vs. 125 +/- 3.5 mg/day/100 g body wt), and a decrease in the urea clearance rate (1.99 +/- 0.14 vs. 3.16 +/- 0.12 ml/min/kg). The urea appearance rate increased on the first day of diuretic administration, remained elevated three days after stopping diuretics, rapidly returned to control levels after sodium repletion, and was significantly correlated with the magnitude of sodium deficit. Similar results were obtained when diuretic-induced sodium depletion was produced in adrenalectomized animals. After four days of sodium depletion the plasma concentration was increased for some amino acids but not for the plasma total amino acid, nitrogen concentration. The results indicate that sodium depletion increases the urea appearance rate through a mechanism that is independent of adrenal function. Thirty to sixty percent of the elevation in plasma urea concentration that occurs in the rat during diuretic-induced sodium depletion can be accounted for by an enhanced urea appearance rate.

Preliminary evidence for genetic determination of intraerythrocytic sodium concentration in Utah pedigrees

Intraerythrocytic sodium concentration has been reported to be increased in hypertensive individuals and some of their normotensive relatives. We investigated the "familiality" of this trait in 572 nonhypertensive subjects from 34 Utah kindreds. Most of these kindreds were selected because of a high incidence of hypertension, heart attack, or stroke. Intraerythrocytic sodium concentration was correlated with the sex of the subject and suprailiac skinfold thickness. Intraerythrocytic sodium concentration was adjusted by linear regression for these 2 factors. The residual values were positively correlated in parent-offspring pairs and among sibs, both those presumed to be living together and those presumed to be living apart. The spouse-spouse correlation was not significant. Pedigree analysis suggested a mixed major-gene/polygenic model of inheritance, but these data did not allow us to distinguish between dominant and recessive inheritance for the major gene component. Total heritability due to both major-gene and polygenic components was estimated to be 90-95%; the proportion of the total variance due to polygenes was estimated to be 60-75%. These results suggest that further study of the relationship between the inheritance of intraerythrocytic sodium and the pathophysiology of hypertension is warranted.

A TATA box implicated in E1A transcriptional activation of a simple adenovirus 2 promoter

Adenovirus E1A proteins stimulate transcription by RNA polymerases II and III from many promoters. The detailed mechanism of transcriptional activation (transactivation) by E1A proteins remains unclear, but genetic and biochemical results suggest that E1A products might act to stimulate the activity of cellular transcription factors. In this study, a detailed mutational analysis of the adenovirus E1B promoter was undertaken to define the DNA sequences required for proper basal transcription and E1A transactivation. Two key findings emerged: first the E1B promoter is an unusually simple RNA polymerase II promoter requiring only two sequence elements for proper regulation, the TATA box and a binding site for transcription factor Sp1; and second only mutations in the TATA box interfere with E1A-transactivation, suggesting that E1A mediates its effect on this promoter through the TATA-box transcription factor.

Major locus inheritance of apolipoprotein B in Utah pedigrees

A major locus that determines levels of apolipoprotein B (apoB) was revealed by likelihood analysis on 331 members of 36 pedigrees. The major locus explained 43.2% of the observed variance, with the remainder attributed to random environmental factors. Estimated mean apoB levels (mg/dl) were 110.5 +/- 2.5, 141.9 +/- 4.4, and 208.1 +/- 11.5 for low homozygotes, heterozygotes, and high homozygotes, respectively. The corresponding genotypic frequencies were 0.718, 0.259, and 0.023. The apoB locus explained 13% and 14% of the variance in total and low-density-lipoprotein cholesterol levels, respectively. Persons with elevated apoB had normal to high levels of total serum cholesterol and triglyceride and low to normal levels of high-density lipoprotein and apolipoprotein A-I. Sixteen members of three of the pedigrees were heterozygous for familial hypercholesterolemia (FH). Their apoB levels were estimated as 35.72 +/- 7.16 mg/dl above the apoB genotypic means, assuming that the two loci act independently. Therefore, two major loci, the FH locus and the apoB locus, affect two levels, apoB and LDL cholesterol.

A DNA probe for the LDL receptor gene is tightly linked to hypercholesterolemia in a pedigree with early coronary disease

A large, multigenerational family with dominantly inherited hypercholesterolemia was analyzed for genetic linkage between blood levels of low-density lipoprotein (LDL) cholesterol and the locus for the LDL receptor. A genetic marker was identified by restriction fragment length polymorphism (RFLP) in a cloned segment of the LDL receptor gene. We found no exceptions to segregation of the high-LDL cholesterol phenotype with a unique allele at the LDL receptor locus in this pedigree; tight linkage was indicated by a maximum lod score of 7.52 at theta = 0. Knowledge of the LDL receptor genotype will enable investigators to study variability of phenotypic expression in response to environmental influences or to different genetic determinants.

Methylenedioxymethamphetamine: a potentially neurotoxic amphetamine analogue

The amphetamine analogue, methylenedioxymethamphetamine (MDMA) has received considerable attention recently as a novel and increasingly popular psychoactive agent. When administered acutely to rats in high doses, MDMA caused a selective and dramatic decrease in brain concentrations of serotonin and its metabolite, 5-hydroxyindoleacetic acid. The depletion of serotonin and its metabolite persisted for up to at least one week after a single injection of MDMA at approximately four to five times the acute dose reported for humans. These results are discussed in terms of the possible neurotoxic effects of MDMA.

Relationship between the structure of chromosomal protein HMG1 and its accumulation in the cell nucleus

When microinjected into the cytoplasm of cultured mammalian cells, non-histone chromosomal protein HMG1 migrates into the nucleus and binds to the chromatin. To define the features of the HMG1 molecule which are essential for this activity, fragments of HMG1 and chemically modified HMG1 molecules were injected into HeLa cells and the capacity of each of these probes to accumulate in the nucleus was measured by an autoradiographic technique. Fragments representing the C-terminal and central portions of HMG1 did not concentrate in the nucleus; a fragment which consisted of the N-terminal two-thirds of the molecule and which lacked the 41 consecutive aspartate and glutamate residues located near the C-terminal end of the molecule accumulated to about the same extent as intact HMG1. When the amino groups of HMG1 were chemically modified, there was a progressive loss in the ability of the protein to accumulate in the nucleus; derivatization of one-fourth of the total amino groups reduced the concentration of microinjected protein in the nucleus relative to that in the cytoplasm to one-half of the original value. In contrast, modification of one-fourth of the total carboxyl groups did not significantly affect the capacity of HMG1 to accumulate in the nucleus, although further modification resulted in decreased nuclear accumulation. Iodination of tyrosine residues was without effect and modification of the cysteine residues had only a modest effect on the ability of HMG1 to concentrate in the nucleus.

Binswanger's disease: progressive subcortical encephalopathy or multi-infarct dementia?

Since Binswanger's description of subcortical arteriosclerotic encephalopathy in 1894, numerous cases have been reported. Several authors doubt the validity of this malady, although the majority consider it to be a disease entity. We report seven cases with this type of pallor of myelin, only two of which are accompanied by a history of dementia. Among the seven cases, two had arteriosclerosis of penetrating arteries and arterioles in cerebral white matter. Electron microscopy showed splitting of myelin sheaths, probably the result of edema. In reviewing the blood supply of the cerebral white matter, we conclude that no pathological alterations of medullary branches of the cerebral arteries, the same vessels supplying the white matter, can give rise to such diffuse pallor of white matter and spare the arcuate fibres. This pallor can only be due to cerebral edema, most likely of hypoxic-ischemic, hypotensive, or acidotic origin. We also contend that arteriosclerosis can only cause dementia through multiple infarcts or lacunae, if it indeed leads to dementia.

Systemic venous and pulmonary arterial flow patterns after Fontan's procedure for tricuspid atresia or single ventricle

Despite increasing use of Fontan or modified Fontan repairs, the comparative hemodynamic efficacy of different types of connections are unresolved. Accordingly, we undertook a prospective study designed to determine postoperative flow patterns after Fontan's operation. Seven subjects had tricuspid atresia and eight had single ventricle. Ages ranged from 5 to 38 years (mean 16.4). Ten subjects had nonvalved right atrial-to-pulmonary arterial connection, and four had nonvalved right atrial-to-right ventricular communication. A valved conduit established continuity between the right atrium and right ventricle in one subject. Doppler flow profiles were recorded in the pulmonary artery and in the superior and inferior venae cavae of each. A reference electrocardiogram was used for timing purposes. In 14 patients, forward flow in the pulmonary artery was biphasic. Flow began at the end of the T wave (early ventricular diastole), peaked at or before the P wave (atrial systole), and returned to baseline by the peak of the R wave. Forward flow recommenced at the peak of the R wave (ventricular systole) and returned to baseline at the end of the T wave. Flow in the superior vena cava varied, and could not be recorded in three subjects. Between the end of the P wave and peak of the R wave (atrial systole) flow was reversed in eight, absent in three, and forward in one patient. Forward flow occurred between the peak of the R wave and the end of the T wave and was either continuous or biphasic. Fourteen patients had adequate studies of inferior vena cava flow; reversed flow during atrial systole occurred in 10 subjects.(ABSTRACT TRUNCATED AT 250 WORDS)

Properties of electroretinographic intensity-response functions in retinitis pigmentosa

Dark-adapted electroretinogram (ERG) b-wave amplitudes and implicit times were recorded as a function of stimulus luminance for 15 retinitis pigmentosa (RP) patients and 15 normal subjects. B-wave amplitude as a function of log stimulus luminance was fit by non-linear regression with the Naka-Rushton equation, which has 3 independent parameters: The maximum response (Rmax), slope (n) and half-saturation constant (K). B-wave implicit-time as a function of log stimulus luminance was fit by linear regression. Compared to normal, the RP Rmax values were markedly reduced, suggesting response compression; the RP K values were elevated by an average of 0.76 log unit, suggesting relatively small losses in retinal sensitivity. There was no correspondence between Rmax and visual field area for the RP patients (coefficient of correlation = -0.02). All but 2 of the 15 RP patients had normal or shallower-than-normal implicit-time intensity-response functions, indicating that over most of the dynamic range of the ERG, the implicit-times were either normal or faster-than-normal. These results are discussed in terms of possible RP disease mechanisms.

Pharmacological properties of two amino esters of diphenylpropanoic acid

N, N-Diethylaminoethyl ester and 3-quinuclidinyl ester of 2, 2-diphenylpropanoic acid (compound 1 and 2, respectively) were prepared and pharmacologically evaluated in vitro and in the intact animal. Both compounds attenuated the effects of increasing doses of ACh in the isolated rat ileum (pA2 = 8.40 and 8.55, respectively). These effects were comparable to that of atropine (pA2 = 8.73). The duration of methacholine-induced salivation in male Swiss-Webster mice was significantly decreased by compound 2 but not by compound 1. Cardiorespiratory studies in adult male Sprague-Dawley rats revealed that both compounds shifted the dose-response curves to methacholine in terms of arterial blood pressure, heart rate and respiration upwards; indicative of cholinergic blockade. The observed pharmacological differences between the two compounds may be attributed to apparent in vivo hydrolysis of compound 1 by esterases.

Molecular cloning and expression of the mouse ornithine decarboxylase gene

We used mRNA from a mutant S49 mouse lymphoma cell line that produces ornithine decarboxylase (OrnDCase) as its major protein product to synthesize and clone cDNA. Plasmids containing OrnDCase cDNA were identified by hybrid selection of OrnDCase mRNA and in vitro translation. The two of these with the largest inserts together span 2.05 kilobases of cDNA. Southern blot analysis of DNA from wild-type or mutant S49 cells, cleaved with EcoRI or with BamHI, revealed multiple bands homologous to OrnD-Case cDNA, only one of which was amplified in the mutant cells. RNA transfer blot analysis showed that the major OrnD-Case mRNA in the mouse lymphoma cells is 2.0 kilobases long. A similar size mRNA was found in mouse kidney and was more abundant in the kidneys of mice treated with testosterone, an inducer of OrnDCase activity in that tissue.

Location of amino acid alterations in mutants of aspartate transcarbamoylase: Structural aspects of interallelic complementation

Recent genetic studies of the pyrB locus of Escherichia coli resulted in the characterization of 29 mutant strains harboring defects in the structural gene that encodes the catalytic chains of aspartate transcarbamoylase (carbamoylphosphate: L-aspartate carbamoyltransferase, EC 2.1.3.2). Three alleles, pyrB554, pyrB730, and pyrB748, have been cloned, and their nucleotide sequences have been determined along with that of the wild-type pyrBI operon in order to locate the sites of the alterations in the catalytic chains. Missense mutation pyrB554 leads to replacement of serine-52 by phenylalanine, and the inactive mutant enzyme has properties similar to those of wild-type aspartate transcarbamoylase. The amber mutation pyrB730 results in unstable truncated polypeptide chains 27 amino acids shorter than wild-type chains. Deletion mutation pyrB748 causes the removal of 181 amino acids. Combining these results with knowledge of the crystallographic structure of the wild-type enzyme provides a basis for tentative structural mechanisms for the observed complementation behavior of the mutant proteins.

Experimental study in rabbits of the antishock effect of anisodamine (654-2), and its mechanism of action

The antishock effect of anisodamine (654-2) was observed in different kinds of experimental shock in groups of rabbits--due to late hemorrhage, superior mesenteric artery occlusion, and septic shock from peritonitis. The drug 654-2 significantly alleviated the progress of shock and increased the survival rate of the animals. The therapeutic effect of 654-2 was much better than that of other vasoactive drugs commonly used, such as norepinephrine, phenoxybenzamine, dopamine, and aramine. The antishock mechanism of 654-2 is probably partly due to its protective action on intestinal shock in preventing its effects becoming irreversible. The antishock action of 654-2 both by basic research workers and clinicians merits further study.