Lensectomy in an infant with cri du chat syndrome and cataracts

We report an 11-month-old infant with cri du chat syndrome and cataracts. The chromosomal abnormality was transmitted via a balanced 5/11 translocation from a phenotypically normal mother. The child underwent bilateral cataract extraction and was fitted with extended wear contact lenses. Congenital cataracts may be associated with cri du chat syndrome.

Hydrogen bonding between cytosine and peptides of threonine or serine: is it relevant to the origin of the genetic code?

13C, 15N, and 1H nuclear magnetic resonance measurements indicate that chloroform-soluble threonine-containing tripeptide derivatives, such as t-Boc-Thr-Gly-Gly-OBz, form three strong hydrogen bonds to the cytosine moiety of 2',3'-O-isopropylidene-5'-O-t-butyldimethylsilylcytidine. The C = O and NH of the central peptide residue plus the OH of the threonine side chain appear to form bonds to the N(4')H2, N(3), and C(2) = O, respectively, of the pyrimidine. An association constant calculated from the cytidine 15N(4') nuclear magnetic resonance response to added peptide is four times larger than the corresponding cytosine-guanine constant. It is suggested that cytosine-peptide bonding was part of the primitive genetic coding mechanism early in evolution and accounts for the origin of the cytosine-centered codons for the hydroxy amino acids, serine and threonine, in the present code.

Reversible interconversion of two forms of a valyl-tRNA synthetase-containing protein complex

When an enzyme-containing complex from yeast was incubated in a buffered solution at room temperature, the valyl-transfer RNA synthetase activity and total protein oscillated synchronously between two physical states. This observation suggests a regulatory process that controls a number of enzymes as a group, an integrated function of a kind not heretofore recognized. The two forms of the complex were separated by ammonium sulfate precipitation of one of them in samples withdrawn from the incubated solution every 30 seconds. Glutathione and dithiothreitol in high concentrations (50 mM) enhance formation of the 50% saturated ammonium sulfate-soluble form. Oxidized glutathione, diphosphopyridine nucleotide, triphosphopyridine nucleotide, and a mercurial thiol binding agent in moderate concentrations (0.1 to 1.0 mM) shift the distribution toward the precipitable form. It is suggested that the two forms represent functional and nonfunctional complex-bound enzymes which are interconverted in response to oxidoreductive signals.

Thyroidectomy of SHR: effects on ventricular relaxation and on SR calcium uptake activity

Ventricular hypertrophy and hypothyroidism are each characterized by impaired cardiac muscle relaxation and sarcoplasmic reticulum (SR) calcium uptake activity. A previous report also showed that hypothyroidism does not reverse ventricular hypertrophy (left-to-right ventricular weight ratios) of spontaneously hypertensive rats (SHR). We characterized the effects of thyroidectomy of 8 wk duration on relaxation of ejecting hearts and on SR calcium uptake activity from SHR and nonhypertrophic Wistar-Kyoto rat (WKY) controls. Relaxation was quantified by plotting maximum left ventricular pulse pressure (Pmax) vs. the area under the falling phase of the left ventricular pressure wave at three different pressure loads. Ventricles of euthyroid SHR were characterized by impaired relaxation and depressed SR calcium uptake activity compared with those of euthyroid WKY, confirming earlier studies. Thyroidectomy reduced ventricular relaxation and SR calcium uptake activities to about the same extent in SHR and WKY strains so that these measurements were most depressed in the SHR hypothyroid group. When all groups were considered, the extent of mechanical relaxation ex vivo and the rate of SR calcium uptake in vitro were well correlated.

Nuclear magnetic resonance imaging, a new approach to the investigation of refractory temporal lobe epilepsy

Nuclear magnetic resonance is a noninvasive technique of imaging the brain using signals produced by magnetic fields and radiowaves. Sixteen patients with refractory temporal lobe epilepsy (TLE) had magnetic resonance imaging (MRI) during investigation for possible surgical management. These images plus those of 10 normal controls, were interpreted blind and the results from the TLE patients compared to the EEG and computerized tomographic (CT) scan findings. Fourteen patients compared with one normal control had one or more of the following: small temporal lobe, small mesial temporal structures, small hemisphere, and focal mesial temporal prolonged spin-spin relaxation time. These findings correlated with the electrographically determined seizure focus in 11 patients. Enlarged or asymmetrical temporal horns were seen with equal frequency in patients and controls and did not correlate with the seizure focus. CT scans were less likely to show these changes than MRI. Correlation of the MRI changes with histopathology of resected temporal lobes was poor. MRI reveals structural and possibly functional alterations which may aid in the localization of the seizure focus in the temporal lobes of patients with refractory complex partial seizures.

Inhibition of the reductive activation of a valyl-tRNA synthetase from yeast by unsaturated fatty acids and associated observations on newly found lipophilic substances from yeast

The reductive activation of a valyl-tRNA synthetase from yeast is strongly inhibited by 1-30 microM unsaturated fatty acids, and the inhibition is antagonized by 10-100 microM saturated fatty acids. Diethylstilbestrol also inhibits the activation. The possibility that unesterified palmitoleic and oleic acids are bona fide regulatory effectors is supported by a dramatic inverse relation between their cellular content and the growth rate of commercial bakers' yeast. An increase in the ratio of unsaturated to saturated acids with slowing growth in a laboratory strain, S288C, also supports the regulatory hypothesis. The free fatty acids are extracted into slightly acidified 50% alcohol together with traces of numerous novel lipophilic substances. One of these is suggested to function as a cofactor in conjunction with a heat-stable polypeptide that activates valyl-tRNA synthetase.

A novel thiol-dependent arsenite-sensitive valyl-tRNA synthetase activity from yeast

Arsenite strongly inhibits the activation by thiols of a fraction of the valyl-tRNA synthetase in yeast extracts that precipitates in low concentrations of ammonium sulfate. Once activated, however, the enzyme is insensitive to arsenite. It is suggested that arsenite blocks the function of an enzyme-bound hydrogen-transferring agent that mediates reduction of the enzyme and normally serves as part of an oxido-reduction regulatory mechanism. On gel filtration, much of the arsenite-sensitive activity behaves as a complex of about 500,000 molecular weight, whereas the behavior of the arsenite-insensitive activity is consonant with the molecular weight of 130,000 previously reported for yeast valyl-tRNA synthetase.

Linoleate and possibly linolenate deficiency in a patient on long-term intravenous nutrition at home

A 39-year-old female with scleroderma was maintained on total parenteral nutrition (TPN) at home for four years. She received 2 units of a 10% fat emulsion per week in which 55% of the fatty acids were from linoleate and 7% from linolenate. She was initially placed on TPN because she had difficulty in swallowing due to scleroderma. At the end of four years she had a triene:tetraene ratio of greater than 1. There was evidence of alterations in membrane function due to essential fatty acid deficiency including CNS involvement (blindness, impaired hearing and disorientation) as well as respiratory insufficiency. The diagnosis of membrane involvement was made from gas chromatography (gc) and gc-mass spectroscopy (ms) analysis of red cell membranes which were deficient in linoleate. The patient's immediate cause of death was from respiratory insufficiency.

Management of Candida peritonitis with intravenous amphotericin: Peritoneal fluid antibiotic levels

The child presented in this report received intravenous amphotericin B 0.5 mg/kg every 36 hours, for dialysis-associated Candida peritonitis. Just prior to her third dose of amphotericin B, the peritoneal fluid concentration of this drug was 0.1 mcg/ml, and the simultaneous serum level was 0.2 mcg/ml. An hour following the third amphotericin B dose, the peritoneal fluid and serum concentrations were 0.2 and 0.4 mcg/ml respectively. The minimal inhibitory concentration (MIC) of amphotericin B for the C. albicans isolated from this patient was 0.05 mcg/ml, and the minimal lethal concentration (MLC) was 0.1 mcg/ml. Treatment included concurrent 5-fluorocytosine, and catheter removal. This is the first time that measurements of concentrations of amphotericin B in the peritoneal fluid have been reported in a child with peritonitis.

The assessment of binge eating severity among obese persons

The purpose of this study was to conduct an assessment of binge eating severity among obese persons. Two questionnaires were developed. A 16-item Binge Eating Scale was constructed describing both behavioral manifestations (e.g., eating large amounts of food) and feeling/cognitions surrounding a binge episode (e.g., guilt, fear of being unable to stop eating). An 11-item Cognitive Factors Scale was developed measure two cognitive phenomena thought to be related to binge eating: the tendency to set unrealistic standards for a diet (e.g., eliminating "favorite foods") and low efficacy expectations for sustaining a diet. The results showed that the Binge Eating Scale successfully discriminated among persons judged by trained interviewers to have either no, moderate or severe binge eating problems. Significant correlation between the scales were obtained such that severe bingers tended to set up diets which were unrealistically strict while reporting low efficacy expectations to sustain a diet. The discussion highlighted the differences among obese persons on binge eating severity and emphasized the role of cognitions in the relapse of self control of eating.