彩色多普勒超声检测自体肾和移植肾的肾动脉狭窄

目的 探讨彩色多普勒超声在检测自体肾和移植肾肾动脉狭窄(RAS)中的价值和局限性。方法 回顾性对照分析了临床可疑RAS的30例自体肾和14例移植肾的彩色多普勒超声(US)与磁共振动脉造影(MRA)及动脉血管造影的结果。并将狭窄肾动脉扩张／再通术前后的肾动脉血流速度，肾内小动脉多普勒波形特征(升速时间-AT，升速指数-AI，阻力指数-RI)进行了比较。结果 30例自体肾RAS的超声诊断中有2例假阳性和2例假阴性。14例移植肾RAS阳性的超声检查无误差。肾动脉血流速度和肾内小动脉的多普勒波形在RAS纠正术前后有显著改变。结论 尽管彩色多普勒超声在检测RAS中有局限性，其仍被列为对可疑RAS病例的初步影像检查，并在观测随访RAS纠正术后的肾血流灌注及狭窄复发中有重要作用。综合分析肾动脉及肾内动脉的血流速度和多普勒波形特征并参考有关临床资料有助于提高超声诊断RAS的准确性。     

Induction of selected lipid metabolic enzymes and differentiation-linked structural proteins by air exposure in fetal rat skin explants

The epidermal permeability barrier of premature infants matures rapidly following birth. Previous studies suggest that air exposure could contribute to this acceleration, because: (i) development of a structurally and functionally mature barrier accelerates when fetal rat skin explants are incubated at an air-medium interface, and (ii) occlusion with a water-impermeable membrane prevents this acceleration. To investigate further the effects of air exposure on epidermal barrier ontogenesis, we compared the activities of several key enzymes of lipid metabolism and gene expression of protein markers of epidermal differentiation in fetal rat skin explants grown immersed versus air exposed. The rate-limiting enzymes of cholesterol (HMG CoA reductase) and ceramide (serine palmitoyl transferase) synthesis were not affected. In contrast, the normal developmental increases in activities of glucosylceramide synthase and cholesterol sulfotransferase, responsible for the synthesis of glucosylceramides and cholesterol sulfate, respectively, were accelerated further by air exposure. Additionally, two enzymes required for the final stages of barrier maturation and essential for normal stratum corneum function, beta-glucocerebrosidase, which converts glucosylceramide to ceramide, and steroid sulfatase, which desulfates cholesterol sulfate, also increased with air exposure. Furthermore, filaggrin and loricrin mRNA levels, and filaggrin, loricrin, and involucrin protein levels all increased with air exposure. Finally, occlusion with a water-impermeable membrane prevented both the air-exposure-induced increase in lipid enzyme activity, and the expression of loricrin, filaggrin, and involucrin. Thus, air exposure stimulates selected lipid metabolic enzymes and the gene expression of key structural proteins in fetal epidermis, providing a biochemical basis for air-induced acceleration of permeability barrier maturation in premature infants.     

Oxysterol stimulation of epidermal differentiation is mediated by liver X receptor-beta in murine epidermis

Liver X receptor-alpha and -beta are members of the nuclear hormone receptor superfamily that heterodimerize with retinoid X receptor and are activated by oxysterols. In recent studies we found that treatment of cultured human keratinocytes with oxysterolstimulated differentiation, as demonstrated by increased expression of involucrin and transglutaminase, and inhibited proliferation. The aims of this study were to determine: (i) whether oxysterols applied topically to the skin of mice induce differentiation in normal epidermis; (ii) whether this effect is mediated via liver X receptor-alpha and/or liver X receptor-beta; and (iii) whether oxysterols normalize epidermal morphology in an animal model of epidermal hyperplasia. Topical treatment of normal hairless mice with 22(R)-hydroxycholesterol or 24(S),25-epoxycholesterol resulted in a decrease in epidermal thickness and a decrease in keratinocyte proliferation assayed by proliferating cell nuclear antigen staining. Moreover, oxysterol treatment increased the levels of involucrin, loricrin, and profilaggrin protein and mRNA in the epidermis, indicating that oxysterols stimulate epidermal differentiation. Additionally, topical oxysterol pretreatment improved permeability barrier homeostasis. Whereas liver X receptor-alpha-/- mice revealed no alterations in epidermal differentiation, the epidermis was thinner in liver X receptor-beta-/- mice than in wild-type mice, with a reduced number of proliferating cell nuclear antigen positive cells and a modest reduction in the expression of differentiation markers. Topical oxysterol treatment induced differentiation in liver X receptor-alpha-/- mice whereas in liver X receptor-beta-/- mice there was no increase in the expression of differentiation markers. Whereas both liver X receptor-alpha and liver X receptor-beta are expressed in cultured human keratinocytes and in fetal rat skin, only liver X receptor-beta was observed on northern blotting in adult mouse epidermis. Finally, treatment of hyperproliferative epidermis with oxysterols restored epidermal homeostasis. These studies demonstrate that epidermal differentiation is regulated by liver X receptor-beta and that oxysterols, acting via liver X receptor-beta, can induce differentiation and inhibit proliferation in vivo. The ability of oxysterols to reverse epidermal hyperplasia suggests that these agents could be beneficial for the treatment of skin disorders associated with hyperproliferation and/or altered differentiation.     

Combination alpha-interferon and lamivudine therapy for alpha-interferon-resistant chronic hepatitis B infection: results of a pilot study

Background/Aims: Alpha-interferon achieves seroconversion in about one third of naive patients. Attempts to achieve seroconversion in patients who have previously failed alpha-interferon have proved disappointing. Combination chemotherapy (alpha-interferon with a nucleoside analogue) might provide a treatment alternative for these patients. We have undertaken a phase 2 study in 20 patients who had previously failed at least one course of alpha-interferon. The study was designed to assess the safety, tolerability and efficacy of the combination.Methods: All patients were treated for 16 weeks with alpha-interferon in combination with 12 or 16 weeks of Lamivudine (3′TC). Patients were followed for 16 weeks post-treatment. Pharmacokinetic studies were performed to identify/exclude significant pharmacokinetic drug interaction.Results: The combination was well tolerated, and side-effects of the combination were indistinguishable from the recognised side-effects of alpha-interferon. Pharmacokinetic studies performed on days 1 and 29 did not show any significant interaction. All patients achieved HBV DNA clearance during treatment, but 19 relapsed at the end of treatment. HBeAg/anti-HBe seroconversion was observed for four patients, but was sustained for a single patient (who also had sustained DNA clearance).Conclusions: Combination therapy with alpha-interferon and lamivudine given for 16 weeks appears safe and is well tolerated. However, for this group of patients who had previously failed interferon monotheraphy appears disappointing, and other treatment strategies should be investigated.     

Prevention of deep venous thrombosis of the leg by a very low molecular weight heparin fraction (CY 222) in patients with hemiplegia following cerebral infarction: a randomized pilot study (30 patients)

The effectiveness and safety of a very low molecular weight heparin fraction were evaluated in the prevention of deep-vein thrombosis in patients confined to bed due to hemiplegia consecutive to a recent cerebral infarction. CY 222 was administered within 48 hours of the stroke by one single daily subcutaneous injection of 0.6 ml (= 15,000 U AXa IC) during 14 days. This randomized pilot study involved 30 patients. The effects of CY 222 were assessed in a group of 15 patients compared with a control group of 15 untreated patients. No deep-vein thrombosis was detected by the labelled fibrinogen test in the treated group, as against 12 patients in the control group. Six patients (3 in each group) died during the study. One case of lethal pulmonary embolism was observed and confirmed at autopsy in the control group. In the remaining 5 patients, no systematic autopsy which would have asserted the absence of pulmonary embolism or drug-induced haemorrhage was performed. Numerous standard laboratory tests confirmed that CY 222 was well tolerated.     

Serious paracetamol poisoning and the results of liver transplantation.

Paracetamol poisoning is the most common cause of fulminant liver failure in the United Kingdom. An accurate assessment of prognosis at the time of referral will allow the appropriate application of liver transplantation in this setting. The outcome of 92 patients consecutively admitted to a specialist liver unit with severe poisoning has been examined. In patients who did not have a transplant, a fatal outcome was seen for 26/82 (32%), and was associated with late presentation, coma grade, prothrombin time prolongation, metabolic acidosis, and renal dysfunction. Cerebral oedema, and sepsis were responsible for most deaths. Prognostic criteria defined at King's College Hospital seemed to predict the outcome of patients who did not have a transplant managed on the Birmingham liver unit. Seventeen patients were listed for transplantation, 10 had liver transplantation, and seven of 10 survived. Seven were listed but not transplanted, and one of seven survived. Psychological rehabilitation of patients who had a transplant has not proved difficult. These results suggest a role for liver transplantation in the management of selected patients with paracetamol poisoning.