Kinetics of Permeate Flux Decline in Crossflow Membrane Filtration of Colloidal Suspensions

A series of well-controlled membrane filtration experiments are performed to systematically investigate the dynamic behavior of permeate flux in crossflow membrane filtration of colloidal suspensions. Results are analyzed by a transient permeate flux model which includes an approximate closed-form analytical expression for the change of permeate flux with time. The model is based on a simplified particle mass balance for the early stages of crossflow filtration before a steady-state flux is attained, and Happel's cell model for the hydraulic resistance of the formed particle cake layer. The filtration experiments demonstrate that permeate flux declines faster with increasing feed particle concentration and transmembrane pressure and with a decrease in the particle size of the suspension. It is also shown that crossflow velocity (shear rate) has no effect on permeate flux at the transient stages of crossflow filtration. Pressure relaxation experiments indicate that the particle cake layer is reversible, implying no irreversible deposition (attachment) of particles onto the membrane surface or the accumulated (retained) particles. The experimental results are shown to be in very good agreement with the theoretical predictions, thus verifying the validity of the model for the transient permeate flux in crossflow filtration and the underlying assumptions in the derivation of the model. Copyright 1997 Academic Press.

[The establishment of antigen sandwiched ELISA for detection of total antibodies to hepatitis C virus]

An antigen sandwiched ELISA for detection of the total antibodies to HCV was established using genetically engineered proteins and synthesized peptides located in the structural and nonstructural regions of HCV genomes as coated antigens and were labeled by horseradish peroxidase, respectively. A comparison of antigen sandwiched ELISA with indirect ELISA showed that the sensitivity of sandwiched system (1:128) was little higher than that of indirect ELISA (1:64), the specificities of both systems were all 100%. This reagent may detect all classes of antibody to HCV in serum, mainly IgG and IgM and is a new diagnostic reagent for detection and early diagnosis of HCV infection.

[Primary analysis of the situation of hepatitis G virus infection in different groups of people]

In order to investigate the situation of hepatitis G virus (HGV) infection among different groups of people, two self-selected peptides from HGV NS5 were used to develop an indirect ELISA for anti-HGV IgG detection. 1209 sera from different peoples were detected and the positive rate of anti-HGV IgG was (3.8%). Among these groups the group of non A-E hepatitis had the highest anti-HGV positive rate (20.5%), higher than that in the groups of natural people (0.8%) and other hepatitis patients (3.3%), the difference was significant. The anti-HGV IgG positive rate in the group of HC patients 8.0% was higher than that in other hepatitis A-E patients, the positive rate (8.0%) in paid donors was higher than that in voluntary donors (0%), and that in groups with venereal diseases and HIV infection were 3.6% and 8.0%, respectively. The results suggested that there has higher rate of HGV infection in our country; HGV is the important factor causing non A-E, the paid donors is the dangerous group, they should be strictly screened, and the people with transfusion have higher rate of HGV infection. Since there is different rate of HGV infection in different human population so it is important to study further the epidemiological characteristics of HGV for its prevention.

[The changes of T lymphocyte subsets and serum interleukin-2 receptor in peripheral blood of the pregnant women complicated by systemic lupus erythematosus]

OBJECTIVE

To determine the changes of T lymphocyte subsets, natural killer (NK) cell and serum interleukin-2 receptor (SIL-2R) in peripheral blood of the pregnant women with systemic lupus erythematosus (SLE).

METHODS

T lymphocyte subsets NK cell, and SIL-2R in peripheral blood were detected by flow cytometry (FCM) and enzyme-labeled immunosorbent assay (ELISA) in 14 cases of pregnant women complicated by SLE (SLE+NP), 18 cases of stationary phase SLE (SLE), 20 cases of normal non-pregnant women (NNP) and 20 cases of normal pregnant women (NP).

RESULTS

The percentages of CD4+ cell were decreased significantly in SLE+NP group as compared with the other three groups (P < 0.01); and the ratio of CD4+/CD8+ was decreased significantly in SLE+NP group, as compared that in SLE group and in NNP group (P < 0.01). There were no difference in the number of NK cells among the four groups. The SIL-2R values were found to be increased significantly in the SLE+NP group, as compared with that of other three groups (P < 0.01).

CONCLUSION

The observation on the changes of peripheral T lymphocyte subsets and SIL-2R may be helpful for monitoring progress of SLE during pregnancy.

Simulation and fabrication of attenuated phase-shifting masks: CrF(x)

To acquire the required resolution for 248- and 193-nm lithography, a study of attenuated phase-shifting mask (Att-PSM) technology is in progress. We performed a simulation study using a matrix method to calculate relative transmittance and the amount of phase shift of light through the PSM. However, we found that the average film composition changed with deposition time. Accordingly, optical constants were found to be a strong function of film thickness. Therefore we rearranged the relationship between deposition parameters (e.g., deposition time or gas flow rate ratio) and optical constants (e.g., refractive index and extinction coefficient) to extract the empirical formula for the optical constants with respect to film composition. To verify our simulation study, we fabricated a phase shifter based on our simulation result, which was found to have a transmittance of 8.3% and a phase shift of 179.5 degrees . Consequently, we obtained a reliable optimum condition for the deep-ultraviolet Att-PSM.

Phorbol myristate acetate-dependent association of protein kinase C alpha with phospholipase D1 in intact cells

A phospholipase D1 (PLD1) was purified from rat brain by the use of antibody-coupled protein A Sepharose. We found that protein kinase C alp (PKCalpha) stimulated PLD1 activity in the presence of phorbol myristate acetate (PMA). PMA-dependent association of PKCalpha with PLD1 was verified in NIH-3T3 fibroblast cells, and COS7 cells transiently expressing PLD1 as well as in vitro suggesting that the activation of PLD1 resulted from direct association of PKCalpha with PLD1.

Introduction of the glutamate receptor subunit 1 into motor neurons in vitro and in vivo using a recombinant herpes simplex virus

We developed and characterized a recombinant herpes simplex virus vector and used it to introduce the complementary DNA encoding glutamate receptor subunit 1 flip into postmitotic motor neurons. Infection of purified motor neurons in vitro with this vector resulted in selective, high-level expression of glutamate receptor subunit 1 immunoreactivity in nearly 100% of the neurons. Patch-clamp experiments demonstrated that the protein product of the glutamate receptor subunit 1 flip transgene assembles into functional alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionate (AMPA) receptor channels. Herpes simplex virus-glutamate receptor subunit 1 flip was introduced into spinal cord cells by direct injection into the ventral horn and selectively into motor neurons by sciatic nerve injection. High levels of expression were sustained for at least one week and were accompanied by changes in the ionic permeability of AMPA receptors in transgene-expressing neurons. Throughout the first week of infection, there was little evidence for toxicity. Herpes simplex virus provides a versatile tool for manipulating the glutamate receptor phenotype of postmitotic neurons and will permit study of the role of individual glutamate receptor subunits in neuronal physiology and pathophysiology.

[Alkaloids in the seeds of Zyziphs jujuba Mill]

Two alkaloids were isolated from the seeds of Zyziphs jujuba and identified on the basis of spectral data to be lysicamine and juzirine. These two alkaloids were obtained from the genus for the first time.

Complementing substitutions at the bottom of the barrel influence catalysis and stability of ribulose-bisphosphate carboxylase/oxygenase

The temperature-conditional photosynthesis-deficient mutant 68-4PP of Chlamydomonas reinhardtii results from a Leu-290 to Phe substitution in the chloroplast-encoded large subunit of ribulose-1, 5-bisphosphate carboxylase/oxygenase (EC 4.1.1.39). Although this substitution occurs relatively far from the active site, the mutant enzyme has a reduced ratio of carboxylation to oxygenation in addition to reduced thermal stability in vivo and in vitro. In an attempt to understand the role of this region in catalysis, photosynthesis-competent revertants were selected. Two revertants, named R96-4C and R96-8E, were found to arise from second-site mutations that cause V262L and A222T substitutions, respectively. These intragenic suppressor mutations increase the CO2/O2 specificity and carboxylation Vmax back to wild-type values. Based on the crystal structure of the spinach holoenzyme, Leu-290 is not in van der Waals contact with either Val-262 or Ala-222. However, all three residues are located at the bottom of the alpha/beta-barrel active site and may interact with residues of the nuclear encoded small subunits. It appears that amino acid residues at the interface of large and small subunits can influence both stability and catalysis.

Power Analysis in Covariance Structure Modeling Using GFI and AGFI

Extending earlier work by MacCallum, Browne, and Sugawara (1996), procedures are shown for conducting power analysis of tests of overall fit of covariance structure models when null and alternative levels of model fit are specified in terms of values of the GFI or AGFl fit indexes. Results show that for GFI-based power analyses, holding null and alternative values of GFI fixed, power decreases as degrees of freedom increase, which is a counter-intuitive and undesirable phenomenon indicating lower power for detecting false null hypotheses about simpler models. For AGFI-based analyses, power increases as degrees of freedom increase. However, for both indexes it is shown that it is problematic to establish consistently appropriate values for null and alternative hypotheses about model fit. Because of these problems, it is recommended that the RMSEA index is preferable as a basis for power analysis and model evaluation.

CD1d1 mutant mice are deficient in natural T cells that promptly produce IL-4

Murine CD1 has been implicated in the development and function of an unusual subset of T cells, termed natural T (NT) cells, that coexpress the T cell receptor (TCR) and the natural killer cell receptor NK1.1. Activated NT cells promptly produce large amounts of IL-4, suggesting that these cells can influence the differentiation of CD4+ effector T cell subsets. We have generated mice that carry a mutant CD1d1 gene. NT cell numbers in the thymus, spleen, and liver of these mice were dramatically reduced. Activated splenocytes from mutant mice did not produce IL-4, whereas similarly treated wild-type splenocytes secreted large amounts of this cytokine. These results demonstrate a critical role for CD1 in the positive selection and function of NT cells.

[The detection of human immunodeficiency virus type 1/2 antibody using synthetic peptides]

Four peptides of human immunodeficiency virus (HIV) located in the regions of gp41, gp120, p24 of HIV-1 and gp36 of HIV-2 have been synthesized according to the published amino acid sequences and the positions of antigenetic determinants of viruses by a solid-phase method. An indirect ELISA for detecting antibody against HIV 1/2 was established using these synthetic peptides as the coating antigens. We detected 41 control sera provided by National Institute for the Control of Pharmaceutical and Biological Products. The results indicated that the general coincident rate were 100%, the variant coefficient was less than 10%. A comparison of our reagent with Huayi, Pasteur and Jinhao reagents in detection of 90 positive sera and 140 normal sera for HIV-1/2 showed that the coincident rate was 100% with Pasteur and Jinhao, 99.57% with Huayi. All of 186 sera from patients with other diseases were negative. The reagent are stable at 37 degrees C for 4 days. The results indicated that our reagent is highly specific, sensitive and stable, it can be used for detection of HIV-1/2 infections.

Roles of transmembrane prolines and proline-induced kinks of the lutropin/choriogonadotropin receptor

The lutropin/choriogonadotropin receptor is a seven-helix transmembrane (TM) receptor. A unique feature of TM helices is the content of Pro, which generally is absent in alpha helices of globular proteins. Because Pro disrupts helices and introduces a approximately 26 degrees kink, it has been speculated that Pro plays a crucial role in the structure of TM helices, exoloops, and cytoloops of TM receptors. To examine the roles of the five TM Pros of the lutropin/choriogonadotropin receptor, these residues were individually substituted. Mutant receptors were examined for surface expression, hormone binding, and cAMP induction. Surface expression was monitored after introducing the flag epitope into the receptors. Flag epitopes slightly affected cAMP induction but not hormone binding or surface expression of receptors as monitored by immunofluorescence microscopy and 125I-anti-flag antibody. The results indicate that Pro479 in TM 4 and Pro598 in TM 7 play important yet contrasting roles. Pro479 is crucial for hormone binding at the cell surface but not after solubilization of the receptor. This is more likely due to the Pro side chain than the Pro-induced kink. Pro598 is important for surface expression. The kinks of Pro463 of TM 4, Pro562 of TM 6, or Pro591 of TM 7 are not important because the substitution of Phe for these residues did not significantly impact surface expression, hormone binding, and cAMP induction.

One-week therapy with twice-daily butenafine 1% cream versus vehicle in the treatment of tinea pedis: a multicenter, double-blind trial

BACKGROUND

Butenafine hydrochloride, a benzylamine derivative with potent antifungal activity, has been used in Japan to treat superficial fungal diseases.

OBJECTIVE

We evaluated the safety and efficacy of twice-daily butenafine versus its vehicle in the treatment of interdigital tinea pedis in a multicenter, randomized, double-blind, parallel-group trial.

METHODS

A total of 402 patients with interdigital tinea pedis and a positive potassium hydroxide examination were enrolled. Of the 271 patients who had culture-confirmed tinea pedis and were assessed for efficacy, 132 applied butenafine and 139 applied vehicle twice daily for 1 week. Patients were assessed for mycologic cure, effective treatment, overall cure, and mycologic/clinical cure.

RESULTS

The rates of all four end points were significantly higher with butenafine than with vehicle 5 weeks after treatment ended. Rates of mycologic cure and effective treatment with butenafine were significantly higher than with vehicle at cessation of treatment. Adverse events to treatment occurred in less than 1% of patients treated with butenafine and 2% of patients who applied vehicle.

CONCLUSION

Butenafine applied twice daily for 1 week is highly effective in treating interdigital tinea pedis.

Reactions of isocytochrome c2 in the photosynthetic electron transfer chain of Rhodobacter sphaeroides

Rhodobacter sphaeroides strains lacking cytochrome c2 (cyt c2), the normal electron donor to P870+ in light-oxidized reaction center (RC) complexes, are unable to grow photosynthetically. However, spd mutations that suppress the photosynthetic deficiency of cyt c2 mutants elevate levels of the cyt c2 isoform, isocyt c2. We monitored photosynthetic electron transfer in whole cells, in chromatophores, and with purified components to ascertain if and how isocyt c2 reduced light-oxidized RC complexes. These studies revealed that several fundamental aspects of photosynthetic electron transfer were similar in strains that use isocyt c2 and wild-type cells. For example, P870+ reduction accompanied cytochrome c oxidation. In addition, photosynthetic electron transfer was blocked by the well-known cyt bc1 complex inhibitors antimycin and myxothiazol. However, even at the increased isocyt c2 levels present in these strains (approximately 40% that of cyt c2 in wild-type cells), there was little, if any, of the rapid (< 5 microns) electron transfer to P870+ that is characteristic of cytochromes bound to RC complexes at the time of the light flash. Thus, it appears that isocyt c2 function limits the in vivo rate of P870+ reduction. Indeed, at low ionic strength in vitro, the apparent affinity of isocyt c2 for RC complexes (KD approximately 40 microM) is significantly lower than that of cyt c2 (KD approximately 1.0 microM). This reduced affinity does not appear to result from an altered mode of RC binding by isocyt c2 since electrostatic interactions make similar overall contributions to the binding of both cyt c2 and isocyt c2 to this membrane-bound redox partner. Thus, sequence, structural, or local conformational differences between cyt c2 and isocyt c2 significantly alter their apparent affinities for this physiologically relevant redox partner.

Anti-lipid peroxidization effect of huangdan on chronic renal failure in rats

The activity of superoxide dismutase (SOD) in renal cortex and erythrocytes, the level of lipid peroxidant (LPO) in plasma, renal function and morphology of leftover kidney were examined in rats. The results showed that Huangdan capsule could slow down the increase of BUN and Scr, promote the SOD activity in renal cortex and erythrocytes, reduce the level of LPO in plasma and delay the renal pathological changes in 5/6 nephrectomized rats. The mechanism of Huangdan capsule's antiperoxidant effect, its effect on the renal pathological changes and relationship between the two effects were also discussed.

Ethnic variation of cord plasma apolipoprotein levels in relation to coronary risk level: a study in three ethnic groups of Singapore

In multiracial Singapore, the prevalence of coronary artery disease is highest in ethnic Indian and lowest in ethnic Chinese populations. Since susceptibility to coronary artery disease is closely associated with plasma lipid traits, we studied the cord blood lipid and apolipoprotein profiles of the three ethnic groups in Singapore to determine if ethnic differences in lipid profile are present at birth. The high-risk lipid traits of high LDL-cholesterol, triglycerides and apo B, low HDL-cholesterol and apo A-I were found to be highest in ethnic Indian and lowest in ethnic Chinese populations. This difference was concordant with the relative coronary mortality rates for their respective adult populations in Singapore.

Unexplained elevated maternal serum alpha-fetoprotein levels and pregnancy outcome in twins

OBJECTIVE

To evaluate whether elevated maternal serum alpha-fetoprotein (MSAFP) levels in uncomplicated twin gestations are associated with an increased risk for pregnancy complications and adverse outcomes.

METHODS

A retrospective data-base analysis was conducted of 267 women with twin pregnancies delivered between January 1988 and October 1994, of whom 42 had elevated MSAFP levels and 225 had normal levels. We evaluated rates of preterm delivery (defined as gestational age less than 34 weeks at delivery), birth weight less than 1500 g, twin-to-twin birth weight discordance, small for gestational age (SGA) infants (defined as birth weight below the tenth percentile for gestational age), and fetal malformations. Also assessed were potentially confounding variables such as obstetric and medical histories as well as sociodemographic factors.

RESULTS

Among nulliparous women, an unexplained elevation in MSAFP levels was associated with a statistically significant increased risk for preterm delivery. Among multiparous women, this association is suggested by the data, but not significantly so. An unexplained elevation in MSAFP level was also associated with a significantly increased risk for birth weight less than 1500 g, but this was related to the increased rate of preterm births. No appreciably increased risk was apparent for SGA infants, fetal malformations (other than neural tube defects and abdominal wall defects), or twin-to-twin birth weight discordance.

CONCLUSION

In twin pregnancies, an unexplained elevation in MSAFP level may increase the risk for preterm delivery but not other adverse pregnancy outcomes.

[An experimental study on the treatment of fetal rabbits with intrauterine growth retardation]

OBJECTIVE

To investigate the effect of histocyte activators and vasodilators on the amino acids concentration in fetal rabbits with intrauterine growth retardation (IUGR).

METHODS

The rabbits with IUGR were caused by passive smoking and treated with histocyte activators (adenosine triphosphatase, coenzyme A, cytochrome C, and vasodilators (injectio salviac molfiorrhizae composita, anisodamine). The effects of different remedies on the fetal plasma amino acids' concentration and the fetal development (i.e. birth weight, the weights of fetal liver and fetal brain) were studied.

RESULTS

Both histocyte activators and vasodilators had favorable effects on the improvement of fetal development and the increase of fetal plasma amino acids' concentration. But the action of histocyte activators was stronger than vasodilators.

CONCLUSIONS

The results suggested that vasodilators could improve the uterine-placental flow, and histocyte activators could enhance placental transfer of amino acids. But histocyte activators seem to be better than vasodilators.

[The quantitative and morphological analysis of placenta and brain in rabbits with intrauterine fetal growth retardation]

OBJECTIVE

To observe the changes of quantitative and morphological structure in placenta and fetal brain of rabbits with intrauterine fetal growth retardation (IUGR) resulted from exposure to cigarette smoking.

METHODS

The pure species of 23 pregnant New Zealand rabbits were used and divided into three groups. (1) group A: 9 rabbits were exposed to cigarette smoking everyday in the whole period of pregnancy; (2) group B: 7 rabbits were exposed to cigarette smoking everyday in the late half period of pregnancy; (3) group C: no smoking, as control group. The villus area of placenta, the capillary area in villus and the thickness of granulosa layer in fetal brain were studied by histomorphometric parameter.

RESULTS

It was showed that the placental villus area was decreased significantly in group A than that of the control group. The capillary area in villus of both group A and group B was less than that of the group C. The thickness of granulosa layer in cerebrum and cerebellum of group B is less than that of the control group. Nevertheless, only the thickness of granulosa layer in cerebrum of group B decreased significantly than that of the control group.

CONCLUSIONS

The development of cerebrum in fetal rabbits were influenced significantly by smoking. The development of cerebellum was influenced by smoking mainly in the early half period of pregnancy. It means that the most important time for cerebellum development is the early period of pregnancy and both the early and late half period of pregnancy were important for the cerebrum development.

Horseradish peroxidase permeability across rat nasal mucosa in selective stimulation of substance P innervation with capsaicin

To investigate the physiological role of substance P innervation (SPI) in the nasal mucosa from inhaled irritant macromolecules, SPI in the rat nasal mucosa was selectively stimulated with capsaicin and the degree of horseradish peroxidase (HRP) permeability across the nasal epithelium was evaluated by enzyme immunoassay or by histochemical electron microscopy. The serum level of HRP was reduced significantly in capsaicin-administered rats compared to control rats along the time course with quantitative analysis of the enzyme immunoassay. Control rats showed heavy permeation of HRP across the epithelium, but capsaicin-administered rats showed weak permeation of HRP across the epithelium with histochemical electron microscopy. The epithelial lining and its tight junctions were left intact as judged by electron microscopy. In conclusion, selective stimulation of SPI of the rat nasal mucosa with capsaicin decreased the epithelial absorption permeability to HRP without compromising the epithelial integrity. These findings imply that the physiological role of capsaicin-sensitive SPI in the rat mucosa is to protect the airway from inhaled irritant macromolecules.

Electroosmotic control of chiral separation in capillary zone electrophoresis

The resolution in capillary zone electrophoresis (CZE), with the assumption of diffusion control only, is strongly dependent on the direction and magnitude of electroosmotic flow. In fact, excellent separation resolution will be obtained if the electroosmotic flow is in the opposite direction of the electrophoretic migration. By applying various radial electric potential gradients across the capillary wall, the direct control of the zeta potential and the electroosmotic flow results in a great enhancement of chiral resolution in cyclodextrin-modified CZE. All 12 basic chiral drugs, including (+/-)-ephedrine, (+/-)-pseudoephedrine, (+/-)-norephedrine, (+/-)-epinephrine, (+/-)-norepinephrine, and (+/-)-isoproterenol, are separated and resolved within 22 min of the analysis time. There is no additional band broadening and dispersion introduced by the direct control of electroosmosis with the application of various radial electric potential gradients.

Five restriction fragment length polymorphisms of the APOA1-C3 gene and their influence on lipids and apolipoproteins in healthy Chinese

The distribution of five restriction fragment length polymorphisms (RFLPs) of the APOA1-C3 gene cluster and their influence on serum lipids and apolipoprotein levels was investigated in 151 healthy Chinese of both sexes. The frequencies of the rare alleles at ApaI, BanI, XmnI (A1) and SstI (C3) sites were significantly different in the Chinese when compared to Caucasians as follows: ApaI: 0.25 vs. 0.42 (p < 0.02); BanI: 0.33 vs. 0.16 (p < 0.01); XmnI: X2, 0.30 vs. 0.14, and X3, 0.08 vs 0.05 (p = 0.001); SstI (C3): 0.23 vs. 0.12 (p = 0.011). The frequency of P2 (PstI) at 0.04 was similar to that in Caucasians (0.07). The distribution of the genotypes of all the RFLPs was in Hardy-Weinberg equilibrium in this population. A significant association of the SstI polymorphism of the C3 region with the serum high-density lipoprotein (HDL)-cholesterol level was observed in both men and women, the rarer allele (S2) being associated with higher levels (p < 0.05). 5.8% of the sample variance of the HDL-cholesterol level in this sample could be explained by the SstI polymorphism of the C3 region (F = 6.07, p = 0.003). The association of the SstI locus with serum HDL-cholesterol was stronger in males than in females (R2 = 13.8 and 6.7%, respectively). There was a similar trend of association of the serum apolipoprotein A-I level with the SstI polymorphism, though it did not reach statistical significance. There was no association between the levels of any of the lipid and apolipoproteins studied with RFLPs of the APOA1 gene.

Racial variation of factor VII activity and antigen levels and their correlates in healthy Chinese and Indians at low and high risk for coronary artery disease

Plasma factor VII activity (FVIIc) is one of the independent risk factors of coronary artery disease (CAD) and is controlled by both genetic and environmental factors. South Asians including Indians have one of the highest prevalence and mortality rates from CAD while the Chinese have a much lower risk. Generally accepted risk factors cannot explain the high mortality from CAD in Indians. We examined two hundred and seventy seven Chinese (124 m, 153 f); and 216 healthy Indian (150 m, 66 f) adults for serum lipids; plasma FVIIc and FVIIag levels in order to examine racial variations of these and their correlates in these two populations. Both Indian men and women had significantly higher FVIIc levels (12% and 11%, respectively) than the Chinese even after adjustments of age, BMI and lipids (P < 0.01). In contrast, Indians had significantly lower plasma FVIIag levels than Chinese (8% and 9%, respectively in men and women; P < 0.01). Multiple linear regression analysis shows a strong correlation of FVIIc with serum triglycerides accounting for 4-8% of the total variability of FVIIc in different groups. Further, there was a stronger correlation between FVIIc and FVIIag in Indians than that in the Chinese (0.43 vs. 25) suggesting a greater activation resulting in higher FVIIc in Indians inspite of lower FVIIag levels. The higher FVIIc and stronger activation by triglycerides observed in this study partly explain the higher risk of CAD in Indians.

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.