Pharmacokinetic parameters of nevirapine and efavirenz in relation to antiretroviral efficacy

Optimal adherence is essential for successful antiretroviral therapy. We analyzed the relation between minimum plasma drug concentration (Cmin) and total drug exposure over 24 hr (AUC24) with virologic failure for therapy-adherent patients in the nevirapine (NVP) and efavirenz (EFV) groups of the double nonnucleoside study (2NN), which compared the efficacy of NVP and/or EFV together with stavudine and lamivudine. The objective was to find cutoff values of the Cmin and AUC24 below which the risk of virologic failure increased. The relation between Cmin and AUC24 with virologic failure (never a plasma viral load [pVL] < 50 copies/ml or a rebound to two consecutive pVL > 50 copies/ml) was analyzed with proportional hazard analyses. Data were censored at end of study or change of allocated treatment. The risk of virologic failure with NVP (n = 511) started to increase at a Cmin < 3.1 mg/L (hazard ratio [HR], 1.33; 95% confidence interval [CI], 0.89-1.97), but there was no cutoff value below which a statistically significant increased risk occurred. Neither was such a cutoff point identified for the AUC24. The risk of virologic failure with EFV (n = 312) was significantly increased at a Cmin < 1.1 mg/L (HR, 1.95; 95% CI, 1.08-3.54) and an AUC24 < 40 mg x hr x L1 (HR, 1.95; 95% CI, 1.07-3.54). Both cutoff values represent the median values for adherent patients. These associations were driven by patients from Thailand. Adjusting for geographical region made the association between Cmin and AUC24 with virologic failure statistically nonsignificant. The sensitivity of the Cmin values was too low (29% for NVP, 64% for EFV) to be an adequate predictor for virologic failure. We conclude that identifying the Cmin value for the sole purpose of predicting virologic failure in patients who report to be adherent to NVP or EFV is questionable because of the absence of a concentration-response relation (NVP) or the low sensitivity for such a cutoff value (NVP and EFV).     

Serum vascular endothelial growth factor concentrations and ovarian stromal blood flow are increased in women with polycystic ovaries

The aim of this study was to determine basal serum vascular endothelial growth factor (VEGF) concentrations and Doppler blood flow changes within the ovarian stroma of women with polycystic ovaries (PCO) and women with normal ovaries. Pulsed and colour Doppler blood flows within the ovarian stroma were recorded, and serum VEGF concentrations measured, in the early follicular phase (days 2-3 of a menstrual cycle) in 60 women undergoing ovarian stimulation for in-vitro fertilization. 36 women had normal ovaries, 14 women had PCO as seen on pelvic ultrasound examination and 10 had polycystic ovarian syndrome (PCOS). Mean+/-SD serum VEGF concentrations were significantly higher (P < 0.001) in women with PCO and PCOS (3.4+/-0.7 and 3.2+/-0.66 ng/ml respectively) compared with women with normal ovaries (2.3+/-0.5 ng/ml). Mean peak systolic blood flow velocity (PSV) and time-averaged maximum flow velocity (TAMXV) were significantly higher (P < 0.001) in women with PCO and PCOS compared with women with normal ovaries. The mean PSV were 15+/-4 and 16+/-4 cm/s in women with PCO and PCOS respectively, compared with 9+/-2 cm/s in women with normal ovaries. The TAMXV were 9+/-3 and 11+/-3 cm/s in women with PCO and PCOS respectively compared with women with normal ovaries (5.8+/-1.5 cm/s). Serum VEGF concentrations were positively correlated with PSV (r=0.44, P=0.001) and TAMXV (r=0.45, P < 0.000) in all three groups of women. Higher serum concentrations of VEGF in women with PCO and PCOS may relate to the increased vascularity that underlies the increased blood flow demonstrated by Doppler blood flow velocity measurements in these women. The results may explain the higher risk of ovarian hyperstimulation syndrome in programmes of ovarian stimulation in patients with PCO compared with those with normal ovaries.      

Oral administration of the growth hormone secretagogue NN703 in adult patients with growth hormone deficiency

OBJECTIVE: Little is known of the usefulness of GH secretagogues (GHSs) in GH-deficient (GHD) adults. The objective of this study was to determine the number of responders to treatment with NN703 in GHD adults. DESIGN: A multicentre, randomized, double-blind, and placebo-controlled study. PATIENTS: Ninety-seven GHD adults were included. MEASUREMENTS: The GH response before and after 1 week of oral treatment with NN703 (n = 83) or placebo (n = 14) was determined. The first and last dose of NN703 was 3 mg/kg, whereas the dose of NN703 was 1.5 mg/kg/day during the 6 days between the first and last doses. Furthermore, all 97 patients received 1 micro g/kg GH-releasing hormone (GHRH) 3 weeks after the last dose of NN703. RESULTS: Serum GH peak and area under curve (AUC) values after the first NN703 administration were greater than those after placebo administration (P < 0.05). However, after correction for the lower body mass index (BMI) in the NN703 group, this difference lost statistical significance. After 1 week of therapy, GH peak and AUC values were similar following the final doses of NN703 and placebo. Serum peak and AUC values of other anterior pituitary hormones were similar between the NN703 and placebo groups both after the first and last administration of study drug. Nine of the 83 patients (11%) responded with a serum peak GH concentration >or= 5 micro g/l after the first and/or last NN703 administration, whereas no patient responded after placebo administration. Serum IGF-I was unaffected by 1-week NN703 treatment, whereas serum IGFBP-3 was increased (P < 0.05 vs. placebo) also after correction for BMI. Mean serum peak GH concentration after GHRH administration was 2.1 micro g/l (+/-0.3, SEM), which was higher than that after the first NN703 administration (1.32 +/- 0.3, P < 0.05). CONCLUSION: NN703 administration was generally well tolerated. Eleven per cent of the GHD adult patients responded with a peak GH response >or= 5 micro g/l after the first and/or last administration of oral NN703. Although a majority of GHD adults will not respond to NN703, the present results suggest that oral NN703 treatment could be useful in some adult patients with moderately severe GHD. These patients may be identified by a test dose of GHS.     

Synergistic effects of butyrate on platelet responses to arachidonate, A23187, PGE1, and forskolin

With eukaryotic cells, butyrate is known to induce a series of morphological and biochemical changes that mimic cellular differentiation. With platelets, we have found that butyrate (10 mmol/L) caused an approximately threefold increase in sensitivity to calcium ionophore A23187 and arachidonate. Maximum aggregation was observed at agonist concentrations of 3 mumol/L and 170 mumol/L, respectively, as compared with required concentrations of 10 mumol/L and 400 mumol/L in the absence of butyrate. Similar effects were seen with isobutyric acid, and about one-half the effect was shown with valerate and caproate, but lower homologues showed no synergistic effect. No ultrastructural changes were observed in platelets incubated with butyrate, and the aggregation effects were reversible and returned to normal on removal of butyrate. Membrane fluidity was unchanged by butyrate as measured by changes in the fluorescence depolarization of diphenylhexatriene. Butyrate caused a 60% to 70% increase in the uptake of 3H-arachidonate. Butyrate also potentiated the inhibition of platelet function by prostaglandin E1 and forskolin and uptake of 3H- forskolin was increased approximately 20%. In contrast, platelet response to other agonists (ADP, epinephrine, collagen, thrombin, and platelet-activating factor) was essentially unaffected by butyrate. These results suggest that butyrate may increase the uptake of certain hydophobic agonists and antagonists by platelets. Similar mechanisms for uptake of endogenous effectors may explain the response of eukaryotic cells to butyrate in culture.     

EGF促进RPE细胞β2肾上腺能受体诱导的cAMP形成：受体间交互作用分析

研究证实表皮生长因子(EGF)不影响培养人眼视网膜色常上皮(RPE)细胞cAMP的基础水平，但促进异丙肾上腺索激活β₂受体后诱导cAMP水平升高的效应，井呈量效信赖关系。EGF对腺嘌呤核苷A₂受体激动剂NECA诱导cAMP水子升高的效应没有明显影响．细胞增殖分析表明，EGF刺激人眼RPE细胞增殖，而DibutyrylcAMP和异丙肾上腺素抑制RGF刺激增殖的效应。结果提示，在人眼RPE细胞EGF和β₂受体之间存在受体间交互作用． （中华眼底病杂志，1995，11：25-27）     

A soluble activity from adherent marrow cells cooperates with IL 3 in stimulating growth of pluripotential hematopoietic precursors

Marrow cells from 5-fluorouracil (5-FU)-treated mice formed few or no mixed erythroid colonies when plated in semisolid medium with interleukin 3 (IL 3) and erythropoietin (Ep) alone. When conditioned medium (CM) from plastic-adherent marrow or thymus cells was also included, however, growth of mixed erythroid colonies was strongly stimulated. Both IL 3 and the accessory activity (AA) had to be present at the initiation of the cultures for growth to occur. AA was also produced by a cloned immortalized line (95/1.7) of fibroblastoid marrow cells that lacked macrophage-specific cell surface markers. Colony- stimulating factor-1 (CSF-1) was also released, but not granulocyte colony-stimulating activity. When 95/1.7 CM was analyzed by gel filtration, AA eluted with an apparent size of 35 kd and separated completely from the CSF-1. Biologic assays failed to detect IL 1 or IL 3 activity in 95/1.7 CM. Growth of mixed erythroid colonies from 5-FU- treated marrow is thus stimulated by adherent marrow cell-derived factors that appear distinct not only from the known CSFs including IL 3, but also from IL 1.     

Changes in deoxyribonuclease I inhibitor in mouse spleen after injection of a synthetic polyanion

The synthetic polyanion pyran (a copolymer of divinyl ether and maleic anhydride), if injected into mice, raises the antibody titer against sheep's red blood cells and also activity of serum DNase I and splenic inhibitor of DNase I. At the same time, the weight of the spleen increases. The possible role of the DNase I-inhibitor system in mechanisms of the adjuvant action of the synthetic polyanion is discussed.Research Laboratory of Experimental Immunobiology, Academy of Medical Sciences of the USSR, Moscow. Institute of Medical Radiology, Academy of Medical Sciences of the USSR, Obninsk. (Presented by Academician of the Academy of Medical Sciences of the USSR R. V. Petrov.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 88, No. 12, pp. 678–680, December, 1979.