Human influenza A (H1N2) viruses isolated from China

Reassortant influenza A viruses bearing H1 haemagglutinin and N2 neuraminidase were isolated from humans in China between December 1988 and March 1989. As primary isolation of influenza A (H1N2) viruses from humans had not been reported previously, it was of interest to determine the genetic origin of these virus isolates. The haemagglutinins of the H1N2 viruses were antigenically and genetically related to those of H1 viruses isolated world-wide since 1986, and the neuraminidases of these viruses were antigenically and genetically related to those of recent H3N2 viruses. Partial sequencing of each gene segment of three of the H1N2 viruses revealed that all gene segments except that encoding the haemagglutinin gene were derived from virus of the H3N2 subtype. Sequence differences amongst the neuraminidase, nucleoprotein and nonstructural genes of these three H1N2 reassortant viruses as well as the isolation of reassortants in seven laboratories over a 4 month period make it unlikely that the H1N2 viruses are laboratory artefacts. The spread of these reassortant viruses to other countries has not yet been documented.

[The influence of sodium ferulate on hypotensive effect and urinary excretion of TXB2 after captopril in essential hypertensive patients]

In the present study, the influence of sodium ferulate (SF) on hypotensive effect and urinary excretion of TXB2 after captopril (CAP) was observed in 44 patients with essential hypertension. A single oral dose of CAP (50 mg) decreased mean arterial pressure (MAP) from 16.25 +/- 0.85 to 13.65 +/- 1.14 kPa, n = 28, (P less than 0.01), and increased urinary TXB2 excretion significantly from 119.12 +/- 57.12 to 183.32 +/- 78.61 pg/min, n = 16, (P less than 0.05). The administration of SF 300 mg/d for one day did not affect the MAP. CAP in combination with SF induced a decrease both in MAP from 16.33 +/- 1.14 to 13.83 +/- 1.77 kPa, n = 16, (P less than 0.01) and urinary TXB2 excretion from 155.89 +/- 69.64 to 133.43 +/- 60.01 pg/min, n = 16, (P greater than 0.05) though the latter was not so significant. Compared with the administration of CAP alone, the combination of CAP and SF induced stronger hypotensive effect (P less than 0.05) and the increased urinary TXB2 excretion could be inhibited by SF, but the inhibition to angiotensin converting enzyme was the same. These results suggested that the increased urinary TXB2 excretion by CAP can be inhibited and the hypotensive effect of CAP is potentiated by SF in essential hypertensive patients.

A review of the numerical analysis of blood flow in arterial bifurcations

Arterial bifurcation flow has been of special interest for some years because of its important role in the formation of atherosclerotic plaques and thrombi. To investigate the flow phenomena analytically, four major factors need to be accommodated--the three-dimensionality of a general bifurcation, the pulsatile nature of the laminar flow, the distensibility of the arterial wall and the non-Newtonian character of the blood. In this review, both engineering and medical aspects of each factor are carefully surveyed. It is demonstrated that the latest generation of computational fluid dynamics codes can treat this problem area and that it is both feasible and desirable to investigate the effects of each independent factor.

Grey dynamic model of predicting the long-term effects of drugs and its application to pirenzepine

In an attempt to approach the quantification of the dynamics of drug effects and the prediction of the long-term effects of drugs, a grey dynamic model was proposed and it was applied to predict the long-term effects of pirenzepine on pupils and peripheral leukocytes in dogs. The inconsiderable relative errors between the predicted and observed values suggest that the model-based equations for pupil diameter, neutrophils (%) and lymphocytes (%) which, obtained by fitting the data measured before and during initial 16 wk experiment, are acceptable for predicting the effects after 20- and 24-wk treatment with the drug.

Effect of cyclosporin A on the ontogeny of different T cell sublineages in chickens

We have used a panel of murine mAb against chicken TCR and associated molecules to study the effect of cyclosporin A (CsA) on the ontogeny of the different sublineages of T cells. After injection of CsA (20 mg/kg/day from day 0 to 20) we observed a significant suppression of the normal maturation of the TCR2 (alpha beta TCR) cells in their transition from cortical CD4+CD8+ thymocytes to the mature single positive cells in the thymus medulla. The TCR3 subpopulation, a distinct form of alpha beta-like TCR in chickens, was inhibited from initially developing within the cortex by CsA, indicating that the TCR3 subpopulation is functionally distinct from the TCR2+ cells. In contrast, the maturation and peripheral emigration of TCR1 (gamma delta TCR) cells was unaffected by CsA treatment. Mature splenic T cells sorted for either TCR1+ or TCR2+ subsets were equally sensitive to CsA blockade of Con A-stimulated mitogenesis, indicating that there is no inherent difference in CsA sensitivity between these sublineages. Furthermore, no difference was detected in the expression of class II MHC Ag in thymi of birds treated with olive oil vs CsA. Inasmuch as the mechanism of CsA action appears to involve inhibition of TCR initiated signal transduction for lymphokine synthesis, these data indicate that a similar signaling is involved in thymic repertoire selection for TCR2. The lack of an effect on TCR1 cell maturation suggests that the TCR1 repertoire may not undergo selection in the thymus as do TCR2+ cells.

Effect of cyclosporin A on the ontogeny of different T cell sublineages in chickens

We have used a panel of murine mAb against chicken TCR and associated molecules to study the effect of cyclosporin A (CsA) on the ontogeny of the different sublineages of T cells. After injection of CsA (20 mg/kg/day from day 0 to 20) we observed a significant suppression of the normal maturation of the TCR2 (alpha beta TCR) cells in their transition from cortical CD4+CD8+ thymocytes to the mature single positive cells in the thymus medulla. The TCR3 subpopulation, a distinct form of alpha beta-like TCR in chickens, was inhibited from initially developing within the cortex by CsA, indicating that the TCR3 subpopulation is functionally distinct from the TCR2+ cells. In contrast, the maturation and peripheral emigration of TCR1 (gamma delta TCR) cells was unaffected by CsA treatment. Mature splenic T cells sorted for either TCR1+ or TCR2+ subsets were equally sensitive to CsA blockade of Con A-stimulated mitogenesis, indicating that there is no inherent difference in CsA sensitivity between these sublineages. Furthermore, no difference was detected in the expression of class II MHC Ag in thymi of birds treated with olive oil vs CsA. Inasmuch as the mechanism of CsA action appears to involve inhibition of TCR initiated signal transduction for lymphokine synthesis, these data indicate that a similar signaling is involved in thymic repertoire selection for TCR2. The lack of an effect on TCR1 cell maturation suggests that the TCR1 repertoire may not undergo selection in the thymus as do TCR2+ cells.

[Dynamic changes in depolarization of action potentials by high frequency stimulation in guinea pig papillary muscles]

The effect of high frequency stimulation on rate-dependent depression of depolarization of action potentials was studied with computer and standard microelectrode techniques in guinea pig papillary muscles. After increasing driving frequency from 0.5 to 6 Hz, decreases in Vmax, APA and OS were found. Changes of upstroke velocity during phase 0 between driving frequency 6 and 0.5 Hz could be described as a parabola. The rate-dependent depression of depolarization was exaggerated by tetrodotoxin (TTX), particularly during the accelerating period of phase 0. A progressive decline in Vmax, which could be fitted by a power function curve, was observed after changing driving frequency from 1 to 5 Hz. TTX significantly influenced the decline in Vmax and the regression coefficients in fitted equations.