Effect of shunt surgery on spleen size, portal pressure and oesophageal varices in patients with non-cirrhotic portal hypertension

Shunt surgery is considered to be the treatment of choice in patients with non-cirrhotic portal hypertension. There is little data on the effect of side-to-side lieno-renal (SSLR) shunt on oesophageal variceal size, splenic size and splenic pulp pressure (SPP) in patients with non-cirrhotic portal hypertension. We evaluated pre- and postoperatively endoscopic grading of varices, splenic size and SPP for predicting shunt patency in 86 patients with non-cirrhotic portal hypertension: 56 with extrahepatic portal venous obstruction (EHPVO) and 30 with non-cirrhotic portal fibrosis (NCPF). The EHPVO patients with patent shunts (n= 47) showed significant reduction in SPP (pre-operative 43.56±7.9 vs postoperative 29.96±7.7 cm of saline), splenic size (6.5±2.8 vs 4.00±2.6 cm below costal margin) and varices grades (2.96±0.5 vs 0.92±0.8). Patients with blocked shunt (n= 9) did not show significant reduction in SPP and varices grades. However, there was reduction in spleen size (8.6±3.0 vs 6.3±4.3). In the NCPF group, 28 had patent shunts and showed significant reduction in SPP (46.3±13.5 vs 33.8±7.6 cm of saline), splenic size (9.1±3.3 vs 6.8±4.6 cm below costal margin) and varices grades (2.8±0.7 vs 1.05±0.96). As only two patients with NCPF had blocked shunts, no statistical comparison between patients with patent and patients with blocked shunts could be done. In conclusion, following SSLR, there is a significant reduction in SPP and varices grades in patients with patent shunts. Endoscopic grading of varices can be used to predict shunt patency. However, spleen size is not a good criteria for predicting shunt patency.     

小叶买麻藤中买麻藤甲素的结构研究

从小叶买麻藤[Gnetum parvifolium(Warb.)C.Y.Cheng]茎的乙酸乙酯部分得到五个成分,经理化常数测定、光谱(UV,IR,MS,~1HNMR,~(13)CNMR和2D-NMR)分析和衍生物制备,确定买麻藤甲素为一个新的2-苯基苯并呋喃类化合物,结构为2-(3′,5′-二羟基-4′-甲氧基苯基)_-3-甲氧基5-羟基苯并呋喃。另外三个鉴定为异丹叶大黄素、白黎芦醇和β-谷甾醇.还有一个化合物正在鉴定中。     

Chagas' disease diagnosis: evaluation of several tests in blood bank screening

Blood transfusion is one of the principal routes of transmission of Chagas' disease, a major endemic disease in Latin America. Methods for blood screening are not accurate and may yield false results that lead to high social and economic costs. This study compares two methods of diagnosing Chagas' disease (indirect immunofluorescence and hemagglutination) and several enzyme-linked immunosorbent assays (ELISAs) with regard to specificity and sensitivity, by using human sera with known serologic and parasitologic characteristics, as well as samples with discrepant results on conventional serologic tests. An ELISA using recombinant antigens showed no cross-reactivity with sera that were positive for other diseases. All evaluated ELISAs performed well, and their use may lead to a reduction of more than 50 percent in the number of discordant sera. Further improvements are needed in view of the complexity of the serologic diagnosis of Chagas' disease.     

Beta thalassemia in Melanesia: association with malaria and characterization of a common variant (IVS-1 nt 5 G----C)

Data on the distribution of beta thalassemia among over 6,000 Melanesians reveals a major difference in the carrier rates between populations in the malarious coastal regions of New Guinea and those living in the historically malaria-free Highlands. The island of Maewo in Vanuatu has a particularly high incidence of beta + thalassemia associated with a single restriction enzyme haplotype. Direct cloning into a plasmid vector and sequence analysis demonstrate that the mutation is a G to C transversion at position 5 of intron 1 of the beta- globin gene. Oligonucleotide probe surveys indicate that this variant accounted for all cases of beta thalassemia studied from Maewo. It is also common in coastal Papua New Guinea where haplotype and oligonucleotide probe data suggest that the molecular basis of beta thalassmia is more heterogeneous.     

Partial plasma exchange using albumin replacement: removal and recovery of normal plasma constituents

Using albumin and crystalloid as the only replacement fluids, the effect of partial plasma exchange on the removal and recovery of normal plasma constituents was studied. The results of 30 procedures on 10 individuals were evaluated. Four patterns of removal are described: reduction in the concentration of fibrinogen and C3 were greater than would be expected based upon the extent of the exchange, while IgG, IgM, cholesterol, alkaline phosphatase and SGPT were removed as expected. Reduction of serum glutamicoxalacetic transaminase (SGOT), lactate dehydrogenase (LDH), amylase, and creatine phosphokinase (CPK) averaged 17% less, and uric acid, calcium and K+ averaged 53% less than expected. Concentrations of HCO-3 and glucose did not change. The mean recovery for all constituents except fibrinogen, C3, cholesterol. IgG and IgM was near 100% at 48-72 hr postpheresis. The 72-hr recovery of fibrinogen and complement was 66% and 60%, respectively. Cholesterol recovery was also slow, requiring a minimum of 1 wk to reach prepheresis levels. Measured at a time when quantitative IgM levels were still reduced, alloantibody agglutinating activity (anti-A and anti-B) in a postpheresis sample exceeded prepheresis agglutinating activity. These data demonstrated that, depending upon quantity and frequency of pheresis, partial plasma exchange using albumin replacement may cause progressive marked reduction in concentrations of immunoglobulin, complement, fibrinogen, and cholesterol. Furthermore, newly synthesized antibody may have increased biologic activity.     

An association between clotting factor concentrates use and mortality in human immunodeficiency virus-infected hemophilic patients

There is much evidence that clotting factor concentrates (CFC), especially the so-called intermediate-purity preparations, exert an immunomodulating effect in vitro. The impact of this effect on the outcome of human immunodeficiency virus (HIV) infection in hemophiliacs is still controversial. In this retrospective cohort study, the effects of treatment with CFC on mortality and progression to acquired immunodeficiency syndrome (AIDS) were estimated while controlling for individual risk factors. Logistic regression and survival analysis, including the Cox proportional-hazards regression model, were performed with data from a 11-year follow-up of 225 hemophilic patients seropositive for HIV type 1 (HIV-1) of two hemophilia centers. Mortality and progression to AIDS rates were strongly associated with lower administration of CFC. After adjusting for age, a statistically significant and robust association was observed. The use of CFC was negatively associated with progression to AIDS (P = .0252) and mortality (P = .0033). The adjusted relative hazards of mortality and progression to AIDS rate between the most treated patients (> 700 IU/kg/yr) versus the least treated (< or = 700 IU/kg/yr) were 0.53 (confidence limits, 0.33 to 0.86) and 0.57 (0.39 to 0.84), respectively. Although the effects of other unmeasured risk factors cannot be excluded with certainty, these results suggest that there is a negative association between treatment with CFC and progression to AIDS and mortality.     

The chemotherapy of lymphoblastic lymphoma

Thirty-two patients treated on consecutive Southwest Oncology Group (SWOG) protocols for malignant lymphoma were subsequently diagnosed as having lymphoblastic lymphoma. Combination chemistry, usually adriamycin-based, produced complete responses (CR) in 17 patients (53%). Median survival was 15 mo. Patients achieving a CR survival significantly longer than patients with partial or no response (p < 0.01). Ten of 24 patients not receiving central nervous system (CNS) prophylaxis developed leptomeningeal lymphoma while none of the seven patients who received prophylactic intrathecal cytosine arabinoside or methotrexate developed CNS lymphoma (p = 0.04). Implications of these results for planning future treatment programs of lymphoblastic lymphoma are discussed.     

Asialo-von Willebrand factor inhibits platelet adherence to human arterial subendothelium: discrepancy between ristocetin cofactor activity and primary hemostatic function

Platelet adherence at high wall shear rates requires plasma von Willebrand factor (vWF). Clinically, the ristocetin cofactor (RCof) activity is the only widely available assay for vWF function. When purified vWF is treated with neuraminidase to yield asialo-vWF (AS- vWF), its RCof activity is increased by 20% to 40%. AS-vWF binds to normal human platelets independently of ristocetin and induces platelet aggregation in the presence of fibrinogen. To determine whether AS-vWF also shows an enhanced capacity to support platelet adherence to subendothelium, we used the Baumgartner technique. Intact vWF, AS-vWF, or AS-vWF treated with beta-galactosidase (asialo, agalacto-vWF; AS,AG- vWF) was added to normal citrated whole blood before perfusion over human umbilical artery segments (wall shear rate, 2,600 sec-1). Four micrograms per milliliter AS-vWF caused a 69% reduction in total platelet adherence compared with citrated whole blood (P less than .001), and 4 micrograms/mL AS,AG-vWF led to a 48% reduction (P less than .005). With 4 micrograms/mL intact vWF, the platelet adherence values were not significantly different from the controls. No significant differences in subendothelial platelet thrombi or postperfusion platelet counts were evident among any of the groups. In reconstituted afibrinogenemic perfusates, 4 micrograms/mL AS-vWF caused a 42% reduction in platelet adherence (P less than .05). Thus, AS-vWF is a potent inhibitor of platelet adherence, despite its enhanced RCof specific activity. Abnormalities in vWF carbohydrate may play a role in impaired primary hemostasis in some patients with von Willebrand's disease.