Diagnostic value of maximal treadmill exercise electrocardiogram in predicting coronary artery disease for asymptomatic Chinese male subjects

The value of maximal treadmill exercise electrocardiogram (TEE) in predicting coronary artery disease was evaluated in a consecutive series of 168 asymptomatic Chinese males, aged 41 to 57 years (mean 53) during annual physical examinations. Their resting electrocardiograms (ECGs) showed no abnormal Q-waves. The end-point of TEE achieved the age-predicted maximal heart rate, and no subjects had classic angina pectoris during or after TEE. Thirty-five subjects had positive electrocardiographic changes defined as reversible horizontal or downsloping ST-segment depression greater than or equal to 1.0 mv which lasted greater than or equal to 0.08 sec. Exercise thallium-201 (T1-201) myocardial imaging was performed on all 35 subjects with positive TEE; 30 subjects (86%) demonstrated normal and 5 abnormal scintigrams. Sixteen of the 30 cases with normal T1-201 scans underwent coronary arteriography, of which 14 showed normal arteriograms and two showed a less than 49% stenosis of the luminal diameter in one major artery. Of the 5 cases with abnormal scintigrams, 4 were found to have greater than 50% stenoses in at least one major artery, and only one case had a less than 49% stenosis of the right coronary artery. We concluded that TEE alone for asymptomatic individuals provided limited value in diagnosing significant coronary artery disease, especially in areas of low prevalence.

Immunodiagnosis of clonorchiasis by enzyme-linked immunosorbent assay

The present study applied the indirect enzyme-linked immunosorbent assay (ELISA) technique in the immunodiagnosis of clonorchiasis. Antigen used in this study was extracted from adult worms of Clonorchis sinensis obtained from cats. 132 patients with clonorchiasis, 100 healthy persons and 14 patients with other parasitic infections were studied. Mean O.D. ratio with standard deviation of clonorchiasis was 1.41 +/- 0.21 with 0.95 +/- 0.13 of healthy persons. Results revealed 90.2% to 95.5% of sensitivity and 84% to 99% specificity dependent on the two cut off values of O.D. ratio, i.e. 1.10 and 1.20. Antibody titers derived from O.D. ratio highly correlated with direct titration (Y = 0.0303 +/- 1.1766 X, r = 0.8945). Cross reactions of other parasite infections to clonorchiasis were observed in patients with angiostrongyliasis and schistosomiasis.

An intercistronic stem-loop structure functions as an mRNA decay terminator necessary but insufficient for puf mRNA stability

Segmental differences in stability within the polycistronic transcripts of the puf operon contribute to differential expression of photosynthesis genes in R. capsulatus. The comparatively stable 5' segment of these transcripts ends in a large intercistronic stem-loop structure. We show here that deletion of this RNA hairpin destabilizes the 5' puf mRNA segment but that its insertion at the 3' end of the puf operon transcripts fails to stabilize the labile 3' puf mRNA segment. Evidence is presented that decay of the 3' segment begins with endonucleolytic cleavage in which the intercistronic stem-loop structure does not participate. We conclude that this RNA hairpin is necessary but insufficient for the stability of mRNA upstream of it, and that it functions in message degradation solely as an mRNA decay terminator that protects upstream mRNA segments from degradation by 3' exoribonucleases.

Serum interleukin-2 receptor in systemic lupus erythematosus and rheumatoid arthritis

Interleukin-2 receptor (IL-2R) is expressed on activated lymphocyte after stimulation with antigen or interleukin-2 (IL-2), meanwhile soluble form of the receptor is released. Using enzyme-linked immunosorbent assay, serum IL-2R levels were determined in 34 healthy controls, 61 patients with systemic lupus erythematosus (SLE) and 32 patients with rheumatoid arthritis (RA), yielding mean +/- SD values of 355 +/- 89, 807 +/- 453 and 567 +/- 210 U/ml respectively. In both SLE and RA patients, the active disease group had more markedly elevated serum IL-2R levels compared with those of the inactive group. In patients with SLE, elevated serum IL-2R is associated with lymphopenia, renal disorders, decreased C3 level and increased anti-DNA, thus make it a good parameter to monitor disease activity in SLE.

Isotope partitioning for NAD-malic enzyme from Ascaris suum confirms a steady-state random kinetic mechanism

Isotope partitioning studies beginning with E.[14C]NAD, E.[14C]malate, E.[14C]NAD.Mg2+, and E.Mg.[14C]malate suggest a steady-state random mechanism for the NAD-malic enzyme. Isotope trapping beginning with E.[14C]NAD and with varying concentrations of Mg2+ and malate in the chase solution indicates that Mg2+ is added in rapid equilibrium and must be added prior to malate for productive ternary complex formation. Equal percentage trapping from E.[14C]NAD.Mg and E.Mg.[14C]malate indicates the mechanism is steady-state random with equal off-rates for NAD and malate from E.NAD.Mg.malate. The off-rates for both do not change significantly in the ternary E.Mg.malate and E.NAD.Mg complexes, nor does the off-rate change for NAD from E.NAD. No trapping of malate was obtained from E.[14C]malate, suggesting that this complex is nonproductive. A quantitative analysis of the data allows an estimation of values for a number of the rate constants along the reaction pathway.

Gallotannins inhibit growth, water-insoluble glucan synthesis, and aggregation of mutans streptococci

During screening for anti-plaque agents of plant origin, ethanolic extracts from Melaphis chinensis (Bell), the Chinese Nutgall, exhibited strong inhibition of glucosyltransferase (GTF), in vitro adherence and glucan-induced agglutination of Streptococcus mutans 3209 and S. sobrinus B13. More than 91% inhibition of water-insoluble glucan synthesis from sucrose by GTF was noted at a concentration as low as 7.8 micrograms/mL. Bactericidal effects on other mutans streptococci, S. salivarius, and Actinomyces viscosus were also evident. Through chemical fractionation and analyses, along with bioassays, the active components were identified as gallotannins.

Demonstration of intracardiac tumor and its associated hemodynamic derangement by radionuclide angiography

A case of malignant lymphoma primarily involving the heart is reported for the first time in which the tumor per se and its accompanying hemodynamic abnormalities were demonstrated by radionuclide angiography (RNA). The patient had severe and progressive failure of the right side of the heart of obscure origin. The tumor was pathologically proven to have involvement of the pericardium, right atrium, and right ventricle, causing significant tricuspid and pulmonic obstruction.

Sequence elements essential for rho-dependent transcription termination at lambda tR1

To determine the location of DNA sequences required for the utilization of rho factor in transcription termination at the tR1 terminator of phage lambda, we constructed and analyzed a series of deletion mutants affecting several distinct regions of the cro-gene sequence. Two distinct sequence blocks, rutA and rutB, are shown to be particularly important for rho action at tR1 during in vitro transcription. They are located in the region between the sequence encoding the translation termination codon of cro mRNA and the start of tR1. Although other sequences contribute to rho action, their function can be replaced by unrelated heterologous DNA sequences encoding highly structured RNA segments, while the function of the rut sequences cannot. The lambda tR1 rut sequences encode RNA segments that contain a high proportion of cytidylate residues and that lack extensive intramolecular base pairing. Thus, the rut transcript segments are likely to be parts of the site on the nascent cro RNA that binds specifically with rho factor as an essential step in the termination process. This view is supported further by the findings (Chen, C.-Y. A., Galluppi, G. R., and Richardson, J. P. (1986) Cell 46, 1023-1028) that rho action at tR1 is specifically inhibited by DNA oligonucleotides that form hybrid helices with rut transcript segments. We also examined the effect of the auxiliary transcription factor NusA on transcription of our mutant templates and show that deletion of the boxA sequence of cro gene does not diminish the ability of NusA to reduce rho action at tR1.

Evaluation of enzyme-linked immunosorbent assay for immunodiagnosis of clonorchiasis

Two groups of patients with parasitologically proved clonorchiasis were recruited from among staff and workers of China Petroleum Company at Miao-Li county. There were 86 patients in the pre-treatment group and 143 patients in post-treatment. The latter were defined as those treated for 18 months after a daily dosage of 3 X 25 mg/kg BW/day of praziquantel. Indirect ELISA was performed to detect the serum antibody against Clonorchis sinensis with extracted crude antigen of adult worms obtained from the bile duct of cats. Direct smears of stool for Clonorchis ova were checked concomitantly. Results revealed significant decrease of optical density ratio between pre- and post-treatment groups. Positive ELISA was detected in 79 pre-treatment group patients (91.8%) and in 28 patients (20.7%) of the post-treatment group (p less than 0.01). Distribution of ELISA titers was shown in patients of post-treatment group towards negative from 400 dilution positive in pre-treatment group. One fourth of the post-treatment group patients with positive ELISA still presented Clonorchis ova in their stool. The main cause was non-compliance of medication. The study confirms the value of immunodiagnosis of C. sinensis by ELISA in the field treatment of clonorchiasis.

A comparison of HPLC and TLC in the assessment of amniotic fluid lecithin/sphingomyelin ratio

One hundred amniotic fluid (AF) specimens of women at 28 to 37 weeks gestation were obtained during labor for lecithin/sphingomyelin ratio (L/S ratio) study by using high performance liquid chromatography (HPLC) and thin layer chromatography (TLC). The results are divided into two groups: one with L/S ratio at or more than 2, and the other with L/S ratio of less than 2. Of the 80 measured by HPLC with the ratio of above 2 or 1.3%, one suffered respiratory distress syndrome (RDS); of the 65 measured by TLC also with the ratio of above 2 or 3.1%, two developed RDS. The result bears no great significance here. However, in the groups with L/S ratio of less than two, the results were very significant: 17 of 20 estimated by HPLC happened to have RDS for an incidence of false positive rate of 15% compared with a 54.3% in 16 of the 35 women evaluated by TLC.

Human, yeast and hybrid 3-phosphoglycerate kinase gene expression in yeast

When the gene for yeast 3-phosphoglycerate kinase (PGK) is present on a high copy number plasmid in Saccharomyces cerevisiae, 30-40 percent of yeast protein is produced as PGK. However, when the structural part of this gene is replaced by as many as twenty different heterologous genes, production of gene products is greatly reduced--usually by more than 20 fold. This decrease in protein production is accompanied by large decreases in the steady-state levels of mRNA. However, in contrast to these coding sequences, replacement of the yeast PGK structural gene with a human PGK cDNA has little effect on the steady-state mRNA level in yeast. PGK is a two-domain enzyme and its 3-dimensional structure is highly conserved among species. These observations and others have led us to propose that the PGK protein itself might influence its own mRNA levels (Chen et al., Nucleic Acids Res. 12, pp. 8951-8969, 1984). In addition, data is presented here which suggest that the human PGK mRNA is less efficiently translated than the yeast PGK mRNA. Two different mechanisms of controlling gene expression are indicated. Both mechanisms appear to be independent of gene copy number.

Differences between Indica and Japonica rice varieties in CO2 exchange rates in response to leaf nitrogen and temperature

Four Indica and five Japonica varieties of rice (Oryza sativa L.) were examined to elucidate their differences in photosynthetic activity and dark respiratory rate as influenced by leaf nitrogen levels and temperatures. The photosynthetic rates of single leaf showed correlations with total nitrogen and soluble protein contents in the leaves. Respiratory rate was also positively correlated with the leaf nitrogen content. When compared at the same level of leaf nitrogen or soluble protein content, the four Indica varieties and one of Japonica varieties, Tainung 67, which have some Indica genes derived from one of its parents, showed higher photosynthetic rates than the remaining four Japonica varieties. At the same photosynthetic rate, the Indica varieties showed lower respiratory rate than Japonica varieties. When the leaf temperature rose from 20°C to 30°C, the photosynthetic rate increased by 18 to 41%, whereas the respiratory rate increased by 100 to 150%. These increasing rates in response to temperature were higher in the Japonica than in the Indica varieties. In this respect, Tainung 67 showed the same behavior as of the other four Japonica varieties.

A check-valve device for prevention of regurgitation after endoesophageal intubation

In pull-through endoesophageal intubation, the esophageal tube, which traverses the esophagogastric junction, may render the sphincter function incompetent and subsequently induce regurgitation of gastric contents conveyed to the esophagus, reflux esophagitis, and even aspiration pneumonia. An antireflux check-valve was developed and has been applied to the lower end of the inserted esophageal tube in 30 patients with malignant esophageal obstruction since September, 1982. The results have proven satisfactory.

Transcription termination at lambda tR1 is mediated by interaction of rho with specific single-stranded domains near the 3' end of cro mRNA

To determine whether E. coli rho protein mediates termination of transcription by interacting with specific segments of the nascent transcript, DNA oligonucleotides were used to sequester segments of phage lambda cro mRNA in hybrid helices. Formation of hybrids was demonstrated with RNAase H assays. Oligonucleotides complementary to either of two distinct, single-stranded sequences near the 3' end inhibited rho action at tR1, while oligonucleotides complementary to the sequence between those segments or to more 5' segments did not. The inhibitory oligonucleotides did not affect the elongation of cro mRNA or rho action on other transcripts. The results indicate that termination of transcription at tR1 is dependent upon contact of rho factor with specific, single-stranded domains near the 3' end of cro mRNA.

Active human-yeast chimeric phosphoglycerate kinases engineered by domain interchange

Phosphoglycerate kinase (PGK) is a monomeric protein composed of two domains of approximately equal size, connected by a hinge. Substrate-induced conformational change results in the closure of the active site cleft, which is situated between these two domains. In a study of the relations between structure and function of this enzyme, two interspecies hybrids were constructed, each composed of one domain from the human enzyme and one domain from the yeast enzyme. Despite a 35% difference in the amino acid composition between human and yeast PGK, catalytic properties of the hybrid enzymes are very similar to those of the parental proteins. This result demonstrates that the evolutionary substitutions within these two distantly related molecules do not significantly affect formation of the active site cleft, mechanism of domain closure, or enzyme activity itself.

Saccharomyces cerevisiae secretes and correctly processes human interferon hybrid proteins containing yeast invertase signal peptides

Synthetic oligonucleotides coding for the yeast invertase secretion signal peptide were fused to the gene for the mature form of human interferon (huIFN-alpha 2). Two plasmids (E3 and F2) were constructed. E3 contained the invertase signal codons in a reading frame with the mature huIFN-alpha 2 gene. F2 had a deletion of the codon for alanine at amino acid residue-5 in the invertase signal and an addition of a methionine codon located between the coding sequences for the invertase signal and mature huIFN-alpha 2. Both hybrid genes were located adjacent to the promoter from the 3-phosphoglycerate kinase gene on the multicopy yeast expression plasmid, YEp1PT. Yeast transformants containing these plasmids produced somewhat more IFN than did the same expression plasmid containing the IFN gene with its human secretion signal sequence. HuIFN-alpha 2, purified from the medium of yeast cells containing E3, was found to be processed at the correct site. The huIFN-alpha 2 made by plasmid F2 was found to be completely processed at the junction between the invertase signal (a variant) and the methionine of methionine-huIFN-alpha 2. These results strongly suggested that the invertase signal (or its variant) attached to huIFN was efficiently recognized by the presumed signal recognition particle and was cleaved by the signal peptidase in the yeast cells. These results also suggested that amino acid changes on the right side of the cleavage site did not necessarily prevent cleavage or secretion.

Performance evaluation of an anoxic/oxic activated sludge system: effects of mean cell residence time and anoxic hydraulic retention time

A laboratory investigation has been undertaken to asses the effects of two operating parameters, mean cell residence time (MCRT) and anoxic hydraulic retention time (HRT), on the performance of an anoxic/oxic activated sludge system. The performance of the system was evaluated in terms of its COD, nitrogen, and biomass characteristics. An activated sludge system is capable of producing a better effluent, in terms of COD and nitrogen characteristics, when it is operated in an anoxic/oxic fashion. A longer MCRT and an adequate anoxic HRT are desirable in the operation of an anoxic/oxic activated sludge system. For the wastewater used in this investigation, the anoxic/oxic unit was capable of producing an effluent with the following characteristics when it was operated at MCRT = 20 days, total system HRT = 10 h, and anoxic HRT = 3-5 h: COD = 15 mg/L; VSS = 10 mg/L; TKN = 1.30 mg/L; NH(3) - N = 0.60 mg/L; and NO(2) + NO(3) - N = 5.0 mg/L. A uniform distribution of biomass is achievable in an anoxic/oxic activated sludge system because of the intensive recirculation/convection maintained. The provision of an anoxic zone in the aeration tank promotes a rapid adsorption of feed COD into the biomass without an immediate utilization for cell synthesis. This, in turn, results in a high microbial activity and a lower observed biomass yield in the system. A tertiary treatment efficiency is achievable in an anoxic/oxic activated sludge system with only secondary treatment operations and costs. A conventional activated sludge system can be easily upgraded by converting to the anoxic/oxic operation with minor process modifications.

A general noninteractive multiple toxicity model including probit, logit, and Weibull transformations

A multiple toxicity model for the quantal response of organisms is constructed based on an existing bivariate theory. The main assumption is that the tolerances follow a multivariate normal distribution function. However, any monotone tolerance distribution can be applied by mapping the integration region in the n-dimensional space of transforms on the n-dimensional space of normal equivalent deviates. General requirements to noninteractive bivariate tolerance distributions are discussed, and it is shown that bivariate logit and Weibull distributions, constructed according to the mapping procedure, meet these criteria. The univariate Weibull dose-response model is given a novel interpretation in terms of reactions between toxicant molecules and a hypothetical key receptor of the organism. The application of the multiple toxicity model is demonstrated using literature data for the action of gamma-benzene hexachloride and pyrethrins on flour beetles (Tribolium castaneum). Nonnormal tolerance distributions are needed when the mortality data include extreme response probabilities.

Bronchopulmonary sequestration associated with aspergilloma, with special reference to the finding of radionuclide venoangiography

A case of intralobar bronchopulmonary sequestration associated with aspergilloma was reported. It was suggested by radionuclide venoangiography and aortic cineangiography. The diagnosis was confirmed by subsequent pathologic examination of the lobectomized lung tissue. The pulmonary perfusion scan with 99mTc-MAA showed a perfusion defect in the right lower lung field. Perfusion defect could also be traced in the same anatomical location in the pulmonary phase of radionuclide venoangiography with 99mTc-pertechnetate. However, the area of perfusion defect was visualized as hot area, when the injected radionuclide was pumped into the aorta after its first pass through the lung. The radionuclide venoangiography can efficiently detect abnormal systemic blood supply of the lung tissue. It can be an useful method for suggestive diagnosis of bronchopulmonary sequestration.