[Use of signal averaging system in the study of ventricular late potentials]

Signal-averaged electrocardiograms (SAECGs) were performed in 93 patients with various heart diseases and 20 dogs with experimental acute myocardial infarction. SA-ECGs were recorded with a high-pass bidirectional digital filter Mode FDS which was made by Shanghai Fudan University and Suzhou Medical College. All the patients and dogs were also examined with ART 1200 EPX recorder. Ventricular late potentials (VLPs) were directly recorded from the epicardium with experimental infarction by using composite electrodes and signal averaging system in late stage of coronary ligation. The results showed: VLPs were detected by body surface SA-ECG only in half of the dogs with VLPs detected by the real time mapping on infarction region, but the abnormal SAECGs did reveal the delayed ventricular activity; the data obtained with FDS or ART SA-ECG were similar.

[Pharmacological studies on dingchuanning]

Dingchuanning has been found to increase markedly the perfusion of isolated lung of guinea-pig. It may produce a relaxing effect on the smooth muscles of the isolated trachea, bronchus and lung strips of guinea-pigs, as well as a prominent protective effect on the bronchial asthma induced by inhalation of bronchoconstrictors in conscious guinea-pigs. It also has significant expectorant and antianaphylactic effects and helps to inhibit markedly the SRS-A release from lung tissues and to counteract directly the activity of SRS-A.

[Immunohistochemical characterization of S100 proteinpositive dendritic cells in gastric mucosa]

Immunohistochemical staining was performed by the ABC method using antibody against S100 protein for the identification of dendritic cells (DC) in the gastric mucosa, including gastric ulcer (n = 19), chronic atrophic gastritis (n = 28), gastric carcinoma (n = 65), fetal gastric mucosa (n = 11) and normal controls (n = 15). Lower numbers of DC may indicate an antigen-deficient state in normal and fetal gastric mucosa, while the diverse densities of DC in pathological conditions may reflect the differences in antigenic quantities and qualities and in individual immune responses. The close association between DC and lymphocytes in situ suggest an antigen-presenting capacity of DC controlling the activation of lymphocytes.

Effect of free-cell growth parameters on oxygen concentration profiles in gel-immobilized recombinantEscherichia coli

Oxygen concentration profiles in immobilized recombinant cells were measured using a microsensor. Experimental results showed that the final depth of oxygen penetration in the carrageenan gel was always in the range 80-100 microns for the strains and media used, although profiles of oxygen concentration during the early stages of cell growth depended on the strain and nutrient medium used. Variations in the oxygen profiles corresponded to differences in kinetic parameters measured for the same strains and media in free-cell experiments.

Measurement of oxygen concentration gradients in gel-immobilized recombinantEscherichia coli

In this study, an oxygen microsensor was used to measure oxygen concentration profiles in carrageenan gel particles containing growing, immobilized Escherichia coli B (pTG201). Profiles, which were measured at intervals during continuous culture of gel slabs and beads, became increasingly steep with time. The oxygen penetration depth in the gel decreased with time, eventually reaching a steady state value of approximately 100 microns for both gel beads and slabs. A reaction-diffusion model employing zero-order cell growth kinetics was found to provide an excellent fit to the experimental concentration data. Growth rates estimated from profiles obtained during the first few hours of culture were 0.24h-1 (gel slabs) and 0.18h-1 (beads), compared to a value of 0.30 h-1 measured in free-cell suspensions at 25 degrees C.

Lipoprotein lipase and hepatic triacylglycerol lipase activities in peripheral and skeletal muscle lymph

We studied the interstitial fluid concentration of two lipid-metabolizing enzymes (lipoprotein lipase and hepatic triacylglycerol lipase) to determine their importance in interstitial modification of filtered lipoproteins. Despite the use of a very sensitive lipase assay (1 nmol of fatty acid release/ml/hr), lipase activities in plasma and in peripheral and skeletal muscle lymph from control dogs were below the sensitivity of our assay. After heparin injection, hepatic triacylglycerol lipase and lipoprotein lipase activities in plasma were similar. However, the postheparin hepatic triacylglycerol lipase activities in peripheral and skeletal muscle lymph were only 1.4% and 1.1%, respectively, those of plasma. This concentration is considerably less than the lymph concentration of albumin, which has a similar size to the lipases but has a lymph concentration of 30% to 40% of plasma. Lipoprotein lipase activity in peripheral lymph and skeletal muscle lymph was 2.7% and 4.8%, respectively, of plasma activity. Since lipoprotein lipase has a similar size as hepatic triacylglycerol lipase, the disproportionate amount of lipoprotein lipase in lymph as compared to hepatic triacylglycerol lipase could be due to heparin crossing the capillary endothelium and displacing lipoprotein lipase from peripheral cells. Injection of radioactive heparin confirmed that it does cross into the interstitial space in sufficient concentrations to displace lipase from peripheral cells. We conclude that most of the lipase found in lymph after heparin injection is derived from peripheral cells and not from plasma. Furthermore, hepatic triacylglycerol lipase does not play a role in high density lipoprotein remodeling in interstitial fluid. Therefore, it seems likely that the considerable remodeling of high density lipoprotein that we found previously results from its interaction with peripheral cells.

Pregnancy rates with fresh versus computer-controlled cryopreserved semen for artificial insemination by donor in a private practice setting

From late 1970 through December 1987, 580 women began 733 treatment programs (a total of 3405 insemination cycles) with fresh semen for artificial insemination by donor. The unadjusted pregnancy rate was 48.5% and the cumulative pregnancy rate after seven cycles by life-table analysis was 59.6% with a monthly fecundability of 11.9%. From 1988 to the present, 113 women have begun 115 treatment programs (a total of 371 insemination cycles) with cryopreserved semen for artificial insemination by donor. The unadjusted pregnancy rate to date is 18.3% and the cumulative pregnancy rate after seven cycles by life-table analysis is 48.6% with a monthly fecundability of 5.9%. This report shows that using cryopreserved semen for artificial insemination by donor will take somewhat longer to produce a pregnancy but the ultimate pregnancy rate will be similar to that with fresh semen for artificial insemination by donor.

[Levels of IL-2 receptor in patients with chronic cor pulmonale]

The levels of IL-2R on surface of activity T-lymphocyte were studied by immunoadsorption test in 33 patients with chronic cor pulmonale. Our results suggested that absorption rate of active PBL to IL-2R was higher in patients than that of control group. It was suggested that high IL-2R levels might be effective in resisting against the it infection and plays an important role in restoring the patients' condition.

[Preliminary study of traditional Chinese medicine treatment of minimal brain dysfunction: analysis of 100 cases]

This paper reports the clinical treatment of 100 patients with minimal brain dysfunction (MBD), their age ranged from 7-14.2 years, and the average age was 10.5. Patients were divided into TCM and WM group randomly. The TCM group (80 cases) were treated with the therapy of subdueing hyperactivity of the Liver and invigorating the function of the Spleen by using: Bupleurum chinense, Scutellaria baicalensis, Astragalus membranaceus, Codonopsis pilosula, Ligustrum lucidum, Lophatherum gracile and thread of ivory. The WM group (20 cases) were treated with retalin 5-15 mg twice daily. One course of treatment lasted one month, and effects were evaluated after 1-3 courses of treatment. The results were as follows: In the TCM group, 23 cases were cured (clinical symptom and sign disappeared, 10 IQ units were raised in their intelligence, abnormal electroencephalogram was recovered and there was no recurrence during the first six months after recovery). 46 cases were improved (clinical symptom and sign markedly improved, 4 IQ units raised in intelligence and electroencephalogram improved), and 11 cases ineffective. The effective rate was 86.25%. In the WM group, 6 cases were cured, 12 cases improved and 2 cases ineffective, the clinical effective rate being 90.0%. There was no significant difference between the two groups in this study, but, the side-effects of the TCM group was less than the WM group, and the TCM group had more beneficial effects to improve intelligence, enuresis and the black of orbits. The study showed that the Verbal Scale in Wechsler Intelligence Scale for children is one of the indications of diagnosis and evaluating of the curative effect of MBD.

Comparison of IgG subclass autoantibodies in patients with systemic lupus erythematosus and subacute cutaneous lupus erythematosus

Circulating antinuclear antibodies and in vivo bound immunoglobulins at the dermal-epidermal junction are frequently seen in patients with lupus erythematosus. The present study was designed to examine the distribution of the IgG subclasses of in vivo skin bound IgG and circulating antinuclear antibodies (ANA) in patients with systemic lupus erythematosus (SLE) or subacute cutaneous lupus erythematosus (SCLE). Immunofluorescence studies on skin biopsies showed IgG1 to be the predominant IgG subclass in SCLE patients, present in 20 of 21 (95%) of the specimens. IgG2 was present in 4 patients (19%), IgG3 in 1 (5%), and IgG4 in 7 (33%). The frequencies of IgG2, IgG3, and IgG4 skin staining were significantly higher in the seven SLE patients who were studied: IgG1 in 7/7 (100%), IgG2 in 7/7 (100%) and IgG4 in 6/7 (86%). Immunoblot analysis for the IgG subclasses was performed on serum of 29 patients with SCLE who had antibodies to SSA/Ro antigen. Twenty-seven (93%) of these patients were positive for IgG1 anti-SSA/Ro antibody, while the frequencies for IgG2, IgG3, and IgG4 anti-SSA/Ro were very low. These studies indicate that there is a difference in the IgG subclass antibody response in patients with SLE and SCLE. The presence of more than one subclass antibody may be indicative of systemic disease.

Effects of subacute toluene exposure on neuronal and glial marker proteins in rat brain

The behavior of marker proteins of neurons (gamma-enolase) and glial cells (alpha-enolase, beta-S100 protein and creatine kinase-B) was investigated quantitatively by using enzyme immunoassay systems in toluene-exposed rat brains. Three groups of animals were exposed to toluene vapor at 300 ppm, 1000 ppm, and 3000 ppm, respectively, 8 h/day, 6 days/week, for 2 weeks. After subacute repeated solvent exposure, both neuron-specific gamma-enolase and glial marker proteins displayed an overall concentration-dependent increase tendency in separate brain regions. In cerebrum, only the 3000 ppm group showed a significant increase in alpha-enolase by 27% and creatine kinase-B (CK-B) by 26%. alpha-Enolase and gamma-enolase exhibited a pronounced elevation in cerebellum relative to other brain regions, while beta-S100 protein appeared to be the most markedly altered marker in brainstem. The development of gliosis, which is a frequent phenomenon following CNS damage, is presumed to be responsible for the elevation of glial marker content. Energy metabolism disruption in brain tissues may also bring about the compensatory oversynthesis of glycolytic enzymes such as gamma-enolase, alpha-enolase and CK-B. The dose-dependent alteration patterns following toluene exposure suggest the feasibility of using these brain specific markers to evaluate solvent-induced CNS effects.

Effects of MEK on kinetics of n-hexane metabolites in serum

The neurotoxicity of n-hexane is thought to be caused ultimately by 2,5-hexanedione (2,5-HD), one of the n-hexane metabolites. The potentiation of n-hexane neurotoxicity by co-exposure with MEK, therefore, is suspected to be related to kinetics of 2,5-HD in blood. To clarify the kinetics of n-hexane metabolites in the mixed exposure of n-hexane and MEK, rats were exposed to 2000 ppm n-hexane or a mixture of 2000 ppm n-hexane and 2000 ppm MEK, and the time courses of serum n-hexane metabolites were determined. 2,5-HD in serum increased until 2 h after the end of exposure, when serum 2,5-HD concentration reached a peak of 16.35 micrograms/ml in the n-hexane-alone group. In contrast, 2,5-HD in the mixed exposure group increased much more slowly during and after exposure than in the n-hexane-alone group. It reached a peak of 2.12 micrograms/ml at 8 h after the end of exposure. Serum MBK, a precursor of 2,5-HD in the co-exposure group, was about half in the n-hexane-alone group during exposure. However, MBK decreased more slowly in the co-exposure group than in the n-hexane-alone group after the end of the exposure. The results suggest that co-exposed MEK might inhibit oxidation of n-hexane and decrease clearance of n-hexane metabolites. Co-exposed MEK did not increase serum 2,5-HD, which was considered a main neurotoxic metabolite. Therefore the enhancement of neurotoxicity could not be attributed to increased serum 2,5-HD in the co-exposed group.(ABSTRACT TRUNCATED AT 250 WORDS)

[Electrophysiologic study of ischemic ventricular arrhythmia]

Epicardial composite electrode and isochronal mapping were used in this study to detect ventricular late potentials and ventricular activity sequence during sinus rhythm and ventricular tachycardias. 20 dogs were studied before and during acute ischemia induced by coronary artery ligation, 11 dogs 3-7 days after two-stage ligation of the left anterior descending coronary The effect of lidocaine and verapamil on VLP and reentrant ventricular arrhythmias was studied. The results demonstrated that: (1) Ventricular arrhythmias occurred right after ligation and 3-7 days later after ligation were related to the reentry in infarct myocardia zone; (2) The inhomogeneous conduction and dispersive refractory period provided a suitable milieu for reentry; (3) Reentrant excitation always occurred in a figure 8 configuration and delayed depolarization and continuous activation were reflected as VLPs at composite electrode; (4) Lidocaine in therapeutic dose prolonged the VLPs and interval of V-VLP. The effect of lidocaine on the ischemic zone was directly related to its ability to abolish reentrant ventricular arrhythmias; (5) Verapamil shortened the VLPs and interval of V-VLP, so the action of slow-response action potentials could not be excluded. Further study should be performed in order to demonstrate the precise mechanism of VLP.

Changes in urinary n-hexane metabolites by co-exposure to various concentrations of methyl ethyl ketone and fixed n-hexane levels

To make clear how the n-hexane metabolism is modified by co-exposure with MEK, rats were exposed to various concentrations of MEK mixed with a fixed concentration of n-hexane. Twenty-four male Wistar rats were divided into four equal groups. Each group was exposed for 8 h to 2000 ppm n-hexane, 2000 ppm n-hexane plus 200 ppm MEK, 2000 ppm n-hexane plus 630 ppm MEK and 2000 ppm n-hexane plus 2000 ppm MEK, respectively. Free metabolites and the sum of free and conjugated metabolites of n-hexane were analyzed by gas chromatography. The main metabolite was 2-hexanol during the exposure and 2,5-hexanedione (2,5-HD) after the exposure in any group. The main metabolites, 2-hexanol and 2,5 HD, decreased in inverse proportion to the co-exposed MEK concentrations. The results suggest that augmentation of n-hexane neurotoxicity by MEK co-exposure could not be explained only by 2,5-HD. In addition, 2,5-HD is recommended as an index for biological monitoring of n-hexane exposure. However, one should be careful to evaluate the exposed n-hexane concentration by urinary 2,5-HD, because n-hexane metabolism could be largely modified by co-exposure with MEK.

A porcine rotavirus strain with dual VP7 serotype specificity

Porcine rotavirus MDR-13, which on original isolation showed a two-way antigenic relationship with human rotavirus RV-3, shows VP7 relationships with serotype G5 as well as G3 viruses upon gene reassortment. Analysis of porcine MDR-13 and the MD-UK reassortant revealed marked nucleotide and amino acid similarity of VP7 genes of these viruses with those of both serotype G3 and G5 viruses. Evolution of such a strain, possibly by sequential mutations in the VP7 gene, is discussed.

Expression in yeast of the T-urf13 protein from Texas male-sterile maize mitochondria confers sensitivity to methomyl and to Texas-cytoplasm-specific fungal toxins

The mitochondrial gene T-urf13 from maize (Zea mays L.) with Texas male-sterile (T) cytoplasm codes for a unique 13 kd polypeptide, T-URF13, which is implicated in cytoplasmic male sterility and sensitivity to the insecticide methomyl and to host-specific fungal toxins produced by Helminthosporium maydis race T (HmT toxin) and Phyllosticta maydis (Pm toxin). A chimeric gene coding for T-URF13 fused to the mitochondrial targeting peptide from the Neurospora crassa ATP synthase subunit 9 precursor was constructed. Expression of this gene in the yeast Saccharomyces cerevisiae yielded a polypeptide that was translocated into the membrane fraction of mitochondria and processed to give a protein the same size as maize T-URF13. Methomyl, HmT toxin and Pm toxin inhibited growth of yeast cells expressing the gene fusion on medium containing glycerol as sole carbon source and stimulated respiration with NADH as substrate by isolated mitochondria from these cells. These effects were not observed in yeast cells expressing T-URF13 without a targeting peptide. The results show that T-URF13 is sufficient to confer sensitivity to methomyl and the fungal toxins in a heterologous eukaryotic system, and suggest that mitochondrial localization of T-URF13 is critical for these functions.

Ontogenesis of the electroretinogram in a precocial mammal, the guinea pig (Cavia porcellus)

1. Ontogenesis of the electroretinogram, the mass electrical response of the retina to flash light stimuli, was studied in the guinea pig (Cavia porcellus), a precocial species with visual function at birth. 2. a-Wave components, b-wave, oscillatory potentials, slow PIII, and c-wave responses to flash stimuli developed between 55 and 64 days of gestation (full term is 68-69 days). 3. a-Waves attributable to photoreceptor functions were fully mature at 60 days. 4. ERG development lagged behind the reported critical milestones in retinal development; its prenatal onset indicates that no history of light entrainment is required for initiation of a mature ERG response.

Airway pressure-volume curve estimated by flow interruption during forced expiration

We attempted to estimate the pressure-volume characteristics of airways downstream from the choke point when the airflow was abruptly interrupted during forced expiration. The change of gas volume of the downstream segment after interruption could be estimated by multiplying the maximum flow (Vmax) immediately before interruption by the interruption time because the Vmax is maintained for a short period after airflow interruption at the mouth, as described in our previous report (J. Appl. Physiol. 66: 509-517, 1989). For the pressure of the downstream segment, we used the mouth pressure itself. Airway compliance, a slope of the pressure-volume curve, was measured in an airway model in eight normal subjects, in six patients with chronic obstructive pulmonary disease (COPD), and in one patient with tracheobronchopathia osteochondroplastica. Airway compliance was 0.96 ml/cmH2O in normal subjects and 2.49 ml/cmH2O in COPD patients. This difference of airway compliance was believed to be caused by the longitudinal expansion of the downstream segment and changes in the properties of the airway wall.

An acidic fibroblast growth factor stimulates DNA synthesis, inhibits collagen and alkaline phosphatase synthesis and induces resorption in bone

We have examined the effects of an acidic fibroblast growth factor (aFGF) on bone cell growth and differentiation and on osteoclastic resorption using rat fetus organ cultured calvariae and long bones, respectively. Low concentrations of this aFGF stimulated DNA synthesis (1.28 ng/ml) and inhibited collagen formation (1.28 ng/ml) and alkaline phosphatase activity (0.64 ng/ml) in the isolated calvariae. The inhibition of collagen synthesis was independent of the aFGF's mitogenic effect, and was evident in periosteum-containing and periosteum-free bones, pointing to osteoblasts as the aFGF-responsive cells. Our preparation of aFGF enhanced resorption in the long bones by a calcitonin-inhibitable mechanism. PGE2 release accompanied and indomethacin prevented the enhancement of resorption. By contrast, indomethacin did not block the stimulation of DNA and collagen synthesis caused by our aFGF. These results indicate that our aFGF exerts a PGE2-independent effect on DNA synthesis and collagen synthesis and a PGE2-dependent effect on resorption in bone tissue in vitro.