Association of factor VII genotype with plasma factor VII activity and antigen levels in healthy Indian adults and interaction with triglycerides

Plasma factor VII activity (factor VIIc) is one of the independent risk factors for coronary artery disease and is controlled by both genetic and environmental factors. Several studies in healthy Caucasian subjects have revealed an association of a common genetic polymorphism at residue 353 (Arg-->Gln) of the factor VII gene with plasma factor VIIc. We have investigated the influence of this polymorphism (factor VII Arg/Gln353) on fasting plasma factor VIIc and antigen (factor VIIag) levels and its interaction with triglyceride levels in 185 healthy Dravidian Indians of both sexes (128 men, 57 women). The frequency of Gln353 has been found to be significantly higher in Dravidian Indians (0.29; confidence interval, 0.27 to 0.30) than in Caucasians (0.10). The distribution of factor VII Arg/Gln353 genotypes was at Hardy-Weinberg equilibrium. The carriers of the Gln353 allele had significantly lower plasma factor VIIc and factor VIIag in men (P < .05). The factor VII Arg/Gln353 polymorphism explained 13% and 11% of the total variance of plasma factor VIIc and factor VIIag, respectively, in men (P < .001) and 6% and 9% in women (P > .1). The genotype-specific correlation of factor VIIc and factor VIIag with triglyceride levels was stronger in carriers of the Gln353 allele (r = .38 and .41; P < .001) than in Arg353 homozygotes (r = .09 and .27; P = .19 and .005, respectively).

Nuclear Mutation Inhibits Expression of the Chloroplast Gene That Encodes the Large Subunit of Ribulose-1,5-Bisphosphate Carboxylase/Oxygenase

Chlamydomonas reinhardtii mutant 76-5EN was recovered as a light-sensitive, acetate-requiring strain that failed to complement a chloroplast structural gene mutant of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco; EC 4.1.1.39). Further genetic analysis revealed that the new mutation was inherited in a mendelian pattern, indicating that it resides within the nucleus. The 76-5EN mutant lacks Rubisco holoenzyme but has wild-type levels of whole-chain electron transport activity and chlorophyll. During a 1-min pulse labeling with 35SO42-, little or no Rubisco large-subunit synthesis occurred in the mutant. Nuclear-encoded small subunits were synthesized to a normal level and were subsequently degraded. When analyzed by northern hybridization, the 76-5EN mutant was found to have a decreased level of large-subunit mRNA. Large-subunit mRNA synthesis also appeared to be reduced during a 10-min pulse labeling with [32P]orthophosphate, but the labeled mRNA was stable during a 1-h chase. These results indicate that a nuclear gene mutation specifically disrupts the accumulation of large-subunit mRNA within the chloroplast. A deeper understanding of the nature of the 76-5EN gene may be useful for manipulating the expression of the agronomically important Rubisco enzyme.

Effects of thyroid hormone on the calcium current and isoprenaline-induced background current in rabbit ventricular myocytes

The majority of previous studies have been performed to explain the effects of thyroid hormone on the heart in chronic hyperthyroidism that was usually induced by eight to 10 daily injections of thyroid hormones. However, it is unclear whether or not the electrophysiological effects result from the chronic manifestations of hyperthyroidism and whether thyroid hormone acts directly or indirectly on cardiac myocytes to alter cardiac electrophysiological properties. In order to examine the acute term electrophysiological effects of thyroid hormone applied in vitro and the mechanisms responsible for some of these effects, we investigated the modulatory effects of thyroid hormone on the calcium current and isoprenaline-induced background current in L-triiodothyronine-treated ventricular myocytes of the rabbit. The major findings were as follows. Over 5 h (range, 5-24 h) after treatment of L-triiodothyronine (1 microM) in vitro, the calcium current was increased significantly. Isoprenaline (1 microM) and cyclic AMP (100 microM) caused an increase in the calcium current in both euthyroid and hyperthyroid myocytes. The hyperthyroid myocytes were more sensitive to the effect of beta-adrenergic stimulation on the calcium current and isoprenaline-activated background current. In euthyroid myocytes, acetylcholine (1 microM) produced no or little changes in the amplitude of the calcium current. In hyperthyroid myocytes, acetylcholine markedly reduced the calcium current, however, acetylcholine was ineffective in the presence of sufficient intracellular cyclic AMP (100 microM). Our results suggest that thyroid hormone can affect the cardiac myocytes directly. Furthermore, our results demonstrate that thyroid hormone affects the calcium current and isoprenaline-activated background current. These electrophysiological changes may explain, at least in part, the occurrence of positive inotropy and cardiac arrhythmias that is associated with hyperthyroidism.

Reliability of seizure classification using a semistructured interview

Methods for standardized classification of epileptic seizures are important for both clinical practice and epidemiologic research. In this study, we developed a strategy for standardized classification using a semistructured telephone interview and operational diagnostic criteria. We interviewed 1,957 adults with epilepsy ascertained from voluntary organizations. To confirm and expand the seizure history, we also interviewed a first-degree relative for 67% of subjects and obtained medical records for 59%. Three lay reviewers used all available information to classify seizures. To assess reliability, each reviewer classified a sample of subjects assigned to the others. In addition, an expert physician classified a sample of subjects assigned to two of the reviewers. Agreement was "moderate-substantial" for generalized-onset seizures, both for the comparisons between pairs of lay reviewers and for the neurologist versus lay reviewers. Agreement was "substantial-almost perfect" for partial-onset seizures, both for pairs of lay reviewers and for the neurologist versus lay reviewers. These results suggest that seizures can be reliably classified by lay reviewers, using operational criteria applied to symptoms ascertained in a semistructured telephone interview.

Validity of family history data on severe headache and migraine

This study evaluated the validity of family history data on severe headache and migraine obtained from adult probands with epilepsy in a family study of seizure disorders. We compared the probands' reports of severe headaches and migraines in their parents and full siblings with symptom-based diagnoses based on self-reports. Overall sensitivity was 48% for severe headache and 44% for migraine. When we used reports of severe headaches to screen for migraine headaches in the relatives, sensitivity was 56%. These results indicate that severe headache and migraine are underreported in family history interviews with first-degree relatives. To obtain accurate information on headaches in families for clinical practice and genetic research, direct interviews with each relative may be required.

Thermal Instability of Ribulose-1,5-Bisphosphate Carboxylase/Oxygenase from a Temperature-Conditional Chloroplast Mutant of Chlamydomonas reinhardtii

Mutant 68-4PP of Chlamydomonas reinhardtii has only 10% of the normal level of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) holoenzyme when grown at 35[deg]C. However, when grown at 25[deg]C, the amount of holoenzyme is greater than 35% of the wild-type level, and the purified enzyme has a reduced CO2/O2 specificity factor. These mutant characteristics result from a chloroplast mutation that causes leucine-290 to be replaced by phenylalanine within the Rubisco large-subunit protein. A nuclear mutation (named S52-2B) was previously identified that can suppress both the in vivo instability and reduced CO2/O2 specificity of the mutant enzyme. However, the effect of this nuclear mutation on the in vitro stability of the holoenzyme was not resolved. In the present study, purified Rubisco from mutant 68-4PP was found to be less thermally stable than the wild-type enzyme, and it had maximal carboxylase activity at a lower temperature. When incubated at 35[deg]C, the mutant enzyme lost carboxylase activity at a much faster rate than the wild-type enzyme. However, the nuclear S52-2B suppresor mutation improved the thermal stability of the mutant enzyme in all cases. These results indicate that structural changes in mutant 68-4PP Rubisco can account for its observed inactivation in vitro and degradation in vivo. Such structural alterations are alleviated by the function of a nuclear gene.

The phonetic interpretation of tone in Igbo

This article presents a preliminary study of the phonetic interpretation of tone in Igbo, a Kwa language of southeastern Nigeria. The experimental method varies the speaker's pitch range orthogonally with variation in tonal material, and fits a model to measurements of maxima and minima in the resulting F0 contour. A new interpretation of downstep is proposed as a result.

Effect of marine coral prostanoids, clavulones, on spontaneous beating rate of cultured myocardial cells from fetal mouse hearts

We examined effects of newly discovered marine coral prostanoids, clavulones, isolated from the Japanese stolonifer Clavularia viridis, on the spontaneous beating rate of cultured myocardial cells from fetal mouse hearts. Clavulone caused positive chronotropic action at 2-5 min after addition of clavulone (0.45 microM) to the reaction media of cardiac cells. This effect induced by clavulone was clearly different from the positive inotropic effects of ouabain (10 microM) and Bay K 8644 (0.1 microM) as judged by photoelectric recordings of beating. These results suggest a new biological action of clavulone that has positive chronotropic action on the cultured mouse myocyte preparation.

Optoelectronic architecture for associative memory applicable to 2-D pattern comparison

A simple optoelectronic architecture is defined with capabilities of matching a test image (1-D or 2-D) with stored images. It is shown that if a test image and a complementary stored image together with complementary test image and stored image are compared optically, the emerging light intensity is minimum for the best match (i.e., shortest Hemming distance). This allows the suggested architecture to do efficient parallel comparison and to point out the best matched test image. If the image is presented in a two color scheme (say red-blue) and the memory images are stored in the complimentary color scheme transparency (i.e., blue-red), then a white light source allows comparison and detection of best matched image without the need for a separate set of complimentary images. A time-varying light intensity (or a time-varying thresholding voltage) source and an integrating-threshold device which switches its state when light input falls below a threshold value are two ingredients, which are used to select the best match in parallel. Grey level detection can also be implemented by the scheme. The architecture is also ideally suited to finding the closeness of match of two images.

Limitations of the lipid state hypothesis for atherosclerosis are revealed by X-ray diffraction measurements

The lipid state hypothesis proposes that liquid crystalline states of cholesteryl esters play a role in the development and persistence of the fatty streak lesions characteristic of atherosclerosis. We have tested several corollaries suggested by this hypothesis and find that the ensemble of droplets in atherosclerotic tissue are predominantly in the isotropic (fluid) state at 37.0 degrees C. Furthermore, the liquid-crystalline state transition behavior of these droplets is not influenced significantly by the distribution of component cholesteryl ester species. There are no significant correlations between the transition behavior of the droplets and the age, sex, or race of the subjects from which tissue samples were taken. These results show that the lipid state hypothesis is weak, and that the origin and persistence of fatty streak lesions in humans is probably dominated by other factors.

Quantum confined Stark effect of excitonic transitions in GaAs/AIGaAs MQW structures for implementation of neural networks: basic device requirements

We examine theoretically and experimentally the properties of two electrooptic devices based on quantum confined Stark effect of excitonic transitions. These two devices are shown to be critical in implementation of the Hopfield model as well as other neural type networks for associative memories. P-i(multiquantum wells)-n structures using GaAs/AlGaAs provide a controller-modulator device which has integrating-thresholding properties required of neurons. The p-i-n structures also provide programmable modulators which can serve as a synaptic mask. Using Monte Carlo techniques we examine an all-optical architecture to implement the Hopfield network. No external feedback-thresholding circuitry is required in this implementation due to special design of the controller-modulator device. Speed and stability issues of this architecture are also addressed. The computer simulation results provide valuable insight into how the controllermodulator device should be improved for better network implementation.

Interventional radiologic procedures in the management of the renal transplant patient

Interventional radiologic procedures have become an important adjunct to the management of the renal transplant patient. Numerous problems can be dealt with, and in our experience these have included the diagnosis and treatment of ureteric obstruction, dilatation of renal artery stenoses, drainage of abscesses, hematomas and lymphoceles, management of complications of pancreatitis and treatment of bleeding due to fistulas and pseudoaneurysms.

Production of xanthomegnin and viomellein by species of Aspergillus correlated with mycotoxicosis produced in mice

By using thin-layer chromatography and infrared spectroscopy, xanthomegnin and viomellein have been isolated and identified from species of the Aspergillus ochraceus group. A correlation was established between the occurrence of these fungal quinones in the fungal cultural products and the ability of these products to induce mycotoxicosis in mice. In addition, a method was employed to estimate the amount of xanthomegnin and viomellein produced by the fungi.

The effects of hydroquinone, hematin and heme-containing proteins on prostaglandin biosynthesis by methylcholanthrene-transformed mouse BALB/3T3 fibroblasts

Cultured methylcholanthrene-transformed 3T3 mouse fibroblasts secrete large amounts of prostaglandin into the medium. Prostaglandin biosynthesis by these cells can be stimulated by arachidonic acid and, to a much lesser extent, by glutathione and porphyrin. In the presence of hydroquinone, prostaglandin production is increased; the most striking increases are seen at concentrations that are lethal. Porphyrins, when added to cells in the presence of lethal levels of hydroquinone, inhibit stimulation of prostaglandin E2 synthesis but stimulate the production of prostaglandin F2alpha.

Electron spin resonance spin-label studies of intercalation of ethidium bromide and aromatic amine carcinogens in DNA

A spin-labeled technique has been developed for the study of carcinogen-DNA intercalation mechanisms utilizing a modified ethidium bromide as a model ligand and specifically synthesized spin labels of carcinogenic aromatic amines such as 2-aminofluorene, 2-aminoanthracene, and 6-aminochrysene. The technique takes advantage of the characteristic electron spin resonance anisotropy of the corresponding spin labels complexed with DNA. Analysis of the orientation-dependent information thus obtained has clearly shown that the lignad moieties in all 4 respective complexes are accommodated in adjacent base-pair layers of the DNA with the nitroxide reporter oriented in 1 preferential direction. The geometry of the nitroxide rings with respect to their respective constraining ligands in a particular complex appeared to be largely dependent upon the size of the ligand moiety and the position of the reporter attachment on the ligand molecule. A coplanar configuration is most favored for the spin labels in which the ligand moiety per se is a 3-fused ring with the nitroxide substituted at a position on or close to the longitudinal end of the ligand molecule. Temperature studies in which the heat-induced release of the bound label is monitored by electron spin resonance gives an accurate measure of the complex dissociation characteristics that appear to parallel the helical coil cooperative melting transition monitored by absorbance measurements. The extent of dissociation of the bound spin labels parallels almost exactly the melting, i.e., unzipping of the DNA double helix, suggesting that the spin labels are immobilized by intercalation at the site on the DNA directly involved in the maintenance of the double helical structure. Analysis of the electron spin resonance spectra of the complexes in terms of the extent of immobilization indicates that, for aromatic amine spin labels, two different binding species exist, one strongly immobilized presumably at a guanine-cytosine base-pair region and the other partially immobilized in a region other than guanine-cytosine base pair. Competitive binding of the labels with respect to their parent ligand and binding isotherm results show that nitroxide substitution does not affect the type of binding but does affect the extent of binding, i.e.. binding constant with the labeled compound having a lower affinity.