A locus for familial hypertrophic cardiomyopathy is closely linked to the cardiac myosin heavy chain genes, CRI-L436, and CRI-L329 on chromosome 14 at q11-q12

We report that a gene responsible for familial hypertrophic cardiomyopathy (HC) is closely linked to the cardiac alpha and beta myosin heavy chain (MHC) genes on chromosome 14q11. We have recently shown that probe CRI-L436, derived from the anonymous DNA locus D14S26, detects a polymorphic restriction fragment that segregates with familial HC in affected members of a large Canadian family. Using chromosomal in situ hybridization, we have mapped CRI-L436 to chromosome 14 at q11-q12. Because the cardiac MHC genes also map to this chromosomal band, we have determined the genetic distances between the cardiac beta MHC gene, D14S26, and the familial HC locus. Data presented here show that these three loci are linked within 5 centimorgans on chromosome 14 at q11-q12. The possibility that defects in either the cardiac alpha or beta MHC genes are responsible for familial HC is discussed.     

Quantitation of daunorubicin and its metabolites by high-performance liquid chromatography with electrochemical detection

A selective and sensitive high-performance liquid chromatographic method was developed for the separation and quantitation of daunorubicin and its metabolites in serum, plasma, and other biological fluids. Daunorubicin and metabolites in human plasma were injected directly into the high-performance liquid chromatography system via a loop-column to pre-extract the drugs from the plasma, and quantitated against a multilevel calibration curve with adriamycin as the internal standard. The column effluent was monitored with an electrochemical detector at an applied oxidative potential of 0.65 V and by fluorescence. Daunorubicin and four metabolites were separted and characterized by this method. In a blinded evaluation of accuracy and precision, the mean coefficients of variation were 3.8, 3.6 and 9.8% at concentrations of 150, 75 and 15 ng/ml, respectively, and blank samples gave negligible readings. The amperometric sensitivity was greater than achieved by fluorescence detection, and offers an alternative method for quantitation of these compounds. The new method has a limit of detection of less than 2 ng on column, allowing quantitation of < 10 ng/ml in plasma samples without organic extraction prior to chromatographic analysis.     

Neutralization of native human gamma interferon (HuIFN gamma) by antibodies to a synthetic peptide encoded by the 5' end of HuIFN gamma cDNA

A synthetic peptide corresponding to the N-terminal amino acid sequence of human gamma-interferon (HuIFN gamma), based on the cDNA sequence, was used to produce antibodies in rabbits that were reactive with native HuIFN gamma. Antibodies from all immunized rabbits neutralized the antiviral activity of HuIFN gamma. Significant neutralization of other HuIFN and mouse IFN was not observed. The peptide had the sequence Cys-Tyr-Cys-Gln-Asp-Pro-Tyr-Val-Lys-Glu-Ala-Glu-Asn-Leu-Lys-Lys-Tyr-Phe-Asn-Ala ,and was coupled to keyhole limpet hemocyanin by disulfide linkage with the use of cystamine. The specificity of the antibodies produced to the peptide was compared to that of antibodies produced to native HuIFN gamma by neutralization of HuIFN gamma and by reactivity with peptide in the enzyme-linked immunosorbent assay (ELISA). The ratio of anti-peptide antibody neutralization of HuIFN gamma vs reactivity with peptide in the ELISA was at least 28-fold lower than for anti-HuIFN gamma antibody. Thus the antibodies to peptide and to HuIFN gamma were directed primarily against different determinants on native HuIFN gamma or the anti-HuIFN gamma antiserum probably contained antibodies to additional determinants. The anti-peptide antibodies should be useful for further characterization and purification of HuIFN gamma.     

Transposition of the gene cluster CYC1-OSM1-RAD7 in yeast

A mutant of the yeast Saccharomyces cerevisiae contains an increased amount of iso-1-cytochrome c because two copies of a segment, denoted COR, were transposed to a new position on chromosome VII, while the original COR region was retained at the normal position on chromosome X; this COR segment encompasses the CYC1, OSM1 and RAD7 loci which determine, respectively, iso-1-cytochrome c, osmotic sensitivity and ultraviolet light sensitivity. The analysis of genomic DNA with cloned probes indicates that the length of the COR segment is approximately 12,000 base-pairs. We suggest that certain normal strains of yeast, which possibly may contain reiterated sequences, can produce extended transpositions similar to prokaryotes.     

PHOSPHATE UPTAKE BY SYNECHOCOCCUS LEOPOLIENSIS (CYANOPHYCEAE): ENHANCEMENT BY CALCIUM ION1

The influence of metallic, cations (added at 10 μM-1 mM) on the uptake of orthophosphate from 0.2–10 μM solution by Synechococcus leopoliensis (Racib.) Komarek was investigated. All cations tested except Mg²⁺ and Zn²⁺ stimulated phosphate uptake. The most pronounced stimulation of phosphate uptake was caused by Ca²⁺·Ca²⁺ markedly decreased the half-saturation concentration for orthophosphate uptake, apparently by acting upon the metabolic processes of phosphate transport into the cell. Phosphate did not influence Ca²⁺ fluxes across the cell-surface.     

Differential effects of placental lactogen,growth hormone and prolactin on rat liver ornithine decarboxylase activity in the perinatal period

Ovine placental lactogen, (oPL), ovine growth hormone, (oGH), and ovine prolactin, (oPRL) are present in high concentrations in the fetal circulation late in gestation. To determine if these hormones stimulate the activity of ornithine decarboxylase (ODC), an enzyme widely implicated in the control of cellular growth, rat fetuses were injected $\text{in utero}$ with 100 μg of oPL, oGH, oPRL, rat growth hormone (rGH) or rat prolactin (rPRL) and ODC activity in the livers, hearts, and brains of the fetuses was measured 2, 4, and 6 hours after injection. OPL stimulated fetal liver ODC activity by 282 ± 45% (mean ± SEM) as compared to litter mates injected with buffer alone but oGH, oPRL, rGH and rPRL had no effect on fetal liver ODC activity. However, in neonatal rats 24–48 hours old all five hormones significantly increased liver ODC activity. ODC activities in the hearts and brains of the fetuses and neonates were unaffected by any of the five hormones. In other experiments 50 μg of oPL significantly stimulated fetal liver ODC activity while 250 μg of oGH were without effect. However 25 μg of oGH significantly stimulated liver ODC activity in rat pups 1–2 days after birth. These results suggest that oPL, by its stimulation of ODC activity, has somatotropic effects in the fetus and that rat liver ODC activity becomes responsive to growth hormone and prolactin in the perinatal period.     

Evaluation of flurbiprofen in detrusor instability.

Thirty women with detrusor instability (27 cases idiopathic, and three secondary to multiple sclerosis) completed a double-blind, cross-over trial of the prostaglandin synthetase inhibitor flurbiprofen and a placebo, results being evaluated by questionnaire and cystometry. Frequency, urgency, and urge incontinence were all significantly reduced with flurbiprofen (P less than 0.001, P less than 0.025, and P less than 0.025 respectively), as was the detrusor-pressure rise during bladder filling (P less than 0.01). Side effects, however, occurred in 13 patients while taking flurbiprofen compared with five while taking placebo (P less than 0.025). After the trial 19 patients wished to continue with flurbiprofen. Flurbiprofen is a useful treatment for idiopathic detrusor instability and is well tolerated by most patients.     

Seasonal variation in thyrotropin-releasing hormone (TRH) content of different brain regions and the pineal in the mammalian hibernator, Citellus lateralis

We have measured the endogenous TRH concentration in the pineal and 9 brain regions of a seasonal hibernator, the golden-mantled ground squirrel, during euthermia and hibernation in order to investigate the possibility that changes in TRH concentration might occur in association with naturally-occurring changes in CNS-mediated physiological and behavioral processes. Regional TRH content was assessed by radioimmunoassay in adult animals that were killed during euthermia in the mid-portion of each season and during hibernation in mid-winter. No significant changes in TRH concentration related to season or to hibernation versus euthermic state were noted in the hippocampus, brainstem, or cerebellum. In the olfactory bulb, preoptic area, and pineal, seasonal variation within euthermic groups was evident. During hibernation, statistically significant decreases in TRH content occurred in the forebrain, olfactory bulb, hypothalamus, septum, preoptic area, and midbrain. Significant fluctuations during hibernation were also observed in the pineal. In this structure, TRH concentration varied in relation to the phase of the hibernation bout. TRH content in the last quarter of the bout was three times greater when compared to values observed in the first quarter of the bout. These results suggest that TRH may be involved in the control processes attributed to these regions and support a role for TRH in the neural control of hibernation.     

The early ontogeny of hematopoietic cells studied by grafting cytogenetically labeled tissue anlagen: Localization of a prospective stem cell compartment

The relative contributions of ventral blood island mesoderm and dorsal anterior mesoderm to differentiated lineages of hematopoietic cells was assessed by reciprocal grafting of cytogenetically labeled tissues between 67- and 72-hr-old frog embryos (Shumway stages 15–16). Diploid (2N) and triploid (3N) cell populations from hematopoietic organs were distinguished by Feulgen-DNA microdensitometric analysis. Ventral blood island mesoderm appears to contribute an embryonic erythrocyte population that progressively declines during larval development. Dorsal anterior mesoderm appears to contribute a population of precursor cells that gives rise to differentiated lineages of hematopoietic cells found in the thymus, pronephros, mesonephros, spleen, and blood. Histological examination of the developing dorsal anterior area indicates that extensive vascularization is a prominent characteristic of this region. The dorsal aortae and vasculature surrounding the pronephros may be sites where at least one population of hematopoietic cells matures and subsequently enters circulation.