Hepatitis C, E, F, G, and non-A-G.

Inflammation of the liver is known as hepatitis. Six or seven viruses, hepatitis viruses A through G, are responsible for most cases of viral hepatitis. In this second of a series of three articles, current knowledge regarding hepatitis C, E, F, G, and non-A-G is reviewed. Up to 80% of patients infected with hepatitis C progress to chronic liver disease. Hepatitis E is an enteric hepatitis that is endemic in Asia. Hepatitis F may be a mutant hepatitis C. Hepatitis G is a posttransfusion hepatitis. Non-A-G hepatitis consists of all of the hepatitis viruses awaiting identification. Up-to-date information regarding each of these types of hepatitis viruses is presented herein, because every phase of patient care improves when health care professionals are knowledgeable regarding the illnesses of their clients.     

Hepatitis A, B, C, D, and E. Update on testing and treatment.

Five major types of viral hepatitis have been identified. Hepatitis A is an acute, usually self-limited illness. Prophylaxis with immune globulin (Gamastan, Gammar) is effective in household and sexual contacts of infected patients. Hepatitis B has both acute and chronic forms. Treatment trials for chronic hepatitis B with interferon alfa-2b have shown promise. Hepatitis C is the name now given to non-A non-B hepatitis. Interferon alfa-2b (Intron A) has been approved for treatment of chronic hepatitis C. Hepatitis D occurs only in patients with hepatitis B. The only treatment for hepatitis D is prevention of hepatitis B. Hepatitis E is seen after natural disasters in developing regions of the world. Further advances in serologic testing and treatment of viral hepatitis can be expected.     

Should the criteria for species distinction in adenoviruses be reconsidered? Evidence from canine adenoviruses 1 and 2

Four strains of canine adenovirus type 1 (CAV-1) and two strains of canine adenovirus type 2 (CAV-2) were examined by restriction enzyme analysis. In all cases, CAV-1 could be readily differentiated from CAV-2. Additionally, monoclonal antibodies were prepared against the Mirandola and Manhattan strains of CAV-1 and CAV-2, respectively. 18 of 36 monoclonal antibodies from the CAV-1 fusion and 77 of 160 monoclonal antibodies from the CAV-2 fusion were type-specific by an indirect fluorescent-antibody technique. Moreover, among those type-specific monoclonal antibodies, 13 of the 18 CAV-1 antibodies and 39 of the 77 CAV-2 antibodies specifically neutralized only the homologous virus in vitro. These data, along with other evidence from the literature, suggest that not only should CAV-1 and CAV-2 be recognized as distinct species in the genus mastadenovirus of the family Adenoviridae, but also that the major criterion of species distinction in that family, namely neutralization, should be reconsidered.     

Analysis of tumors arising in male B6C3F1 mice with and without AAV vector delivery to liver.

The present study reports on the frequency of liver tumors observed in a gene therapy study with AAV vectors in male mice of the B6C3F1 hybrid background, which are known to have a high frequency of spontaneous liver tumors. Male mice with mutations in their Otc gene and their wild-type siblings received AAV vectors expressing either the murine Otc or the LacZ gene. Untreated control animals were included in the study. All experimental groups, including wild-type and OTC-deficient animals not treated with vector, developed liver nodules, which in some cases were due to hepatocellular carcinoma. Vector DNA was lower in tumors than in adjacent normal liver. A statistical analysis of the data did not show an association between treatment with Otc vectors and formation of tumors in OTC-deficient mice. However, mice treated with LacZ vectors showed increased risks of tumor formation and hepatocellular carcinoma relative to untreated animals or animals that had received vectors with Otc as the transgene. It appears that AAV vectors alone do not contribute to the formation of tumors in these strains of mice although the expression of LacZ alone or in combination with vector may be problematic.     

Nanoparticle drug delivery system for intravenous delivery of topoisomerase inhibitors.

Camptothecin-based drugs, because of their poor solubility and labile lactone ring, pose challenges for drug delivery. The purpose of this research was to develop a nanoparticle delivery system for camptotheca alkaloids. After initial investigations SN-38 was selected as the candidate camptotheca alkaloid for further development. Nanoparticles comprising SN-38, phospholipids and polyethylene glycol were developed and studied in vitro and in vivo. The SN-38 formulations were stable in human serum albumin and high lactone concentrations were observed even after 3 h. In vivo studies in nude mice showed prolonged half-life of the active (lactone form) drug in whole blood and increased efficacy compared to Camptosar in a mouse xenograft tumor model.     

Phenotypes of apolipoprotein B and apolipoprotein E after liver transplantation.

Apolipoprotein (apo) E and the two B apolipoproteins, apoB48 and apoB100, are important proteins in human lipoprotein metabolism. Commonly occurring polymorphisms in the genes for apoE and apoB result in amino acid substitutions that produce readily detectable phenotypic differences in these proteins. We studied changes in apoE and apoB phenotypes before and after liver transplantation to gain new insights into apolipoprotein physiology. In all 29 patients that we studied, the postoperative serum apoE phenotype of the recipient, as assessed by isoelectric focusing, converted virtually completely to that of the donor, providing evidence that greater than 90% of the apoE in the plasma is synthesized by the liver. In contrast, the cerebrospinal fluid apoE phenotype did not change to the donor's phenotype after liver transplantation, indicating that most of the apoE in CSF cannot be derived from the plasma pool and therefore must be synthesized locally. The apoB100 phenotype (assessed with immunoassays using monoclonal antibody MB19, an antibody that detects a two-allele polymorphism in apoB) invariably converted to the phenotype of the donor. In four normolipidemic patients, we determined the MB19 phenotype of both the apoB100 and apoB48 in the "chylomicron fraction" isolated from plasma 3 h after a fat-rich meal. Interestingly, the apoB100 in the chylomicron fraction invariably had the phenotype of the donor, indicating that the vast majority of the large, triglyceride-rich apoB100-containing lipoproteins that appear in the plasma after a fat-rich meal are actually VLDL of hepatic origin. The MB19 phenotype of the apoB48 in the plasma chylomicron fraction did not change after liver transplantation, indicating that almost all of the apoB48 in plasma chylomicrons is derived from the intestine. These results were consistent with our immunocytochemical studies on intestinal biopsy specimens of organ donors; using apoB-specific monoclonal antibodies, we found evidence for apoB48, but not apoB100, in donor intestinal biopsy specimens.     

Comparison of nociceptive behavior in prostaglandin E,F, D,prostacyclin and thromboxane receptor knockout mice

Antagonist at specific prostaglandin receptors might provide analgesia with a more favourable toxicity profile compared with cyclooxygenase inhibitors. We analyzed nociceptive responses in prostaglandin D, E, F, prostacyclin and thromboxane receptor knockout mice and mice deficient of cyclooxygenase 1 or 2 to evaluate the contribution of individual prostaglandin receptors for heat, mechanical and formalin‐evoked pain. None of the knockouts was uniformly protected from all of these pain stimuli but COX‐1 and EP4 receptor knockouts presented with reduced heat pain and EP3 receptor and COX‐2 knockout mice had reduced licking responses in the 2nd phase of the formalin assay. This was accompanied with reduced c‐Fos immunoreactivity in the spinal cord dorsal horn in EP3 knockouts. Oppositely, heat pain sensitivity was increased in FP, EP1 and EP1+3 double mutant mice possibly due to a loss of FP or EP1 receptor mediated central control of thermal pain sensitivity. Deficiency of either EP2 or DP1 was associated with increased formalin‐evoked flinching responses and c‐Fos IR in dorsal horn neurons suggesting facilitated spinal cord pain reflex circuity. Thromboxane and prostacyclin receptor knockout mice showed normal pain behavior in all tests. The results suggest a differential, pain‐stimulus and site‐specific contribution of specific PG‐receptors for the processing of the nociceptive stimuli, a differential modulation of nociceptive responses by COX‐1 and COX‐2 derived prostaglandins and compensatory and/or developmental adaptations in mice lacking specific PG receptors.     

Pattern of insulin delivery after intravenous glucose injection in man and its relation to plasma glucose disappearance.

Plasma insulin concentrations after pulse intravenous injection of glucose show an early rise, which declines towards the prestimulation level smoothly. This pattern is the effect of both continuing secretion and hormone disappearance from the plasma. To reconstruct the time-course of the acutal secretory response, we measured insulin disappearance from the plasma of 17 healthy volunteers by means of a bolus intravenous injection of 125I-insulin, and then performed an intravenous glucose tolerance test with frequent blood sampling. The data were analyzed by deconvolution, which made it possible to compute the glucose-induced posthepatic insulin delivery rate minute by minute. Under basal conditions, 2.64 +/- 0.28 (mean +/-SEM) mU/min.m2 reaches the systemic circulation. In the 90 min that follow acute glucose stimulation, 0.86 +/- 0.11 U/m2, a 270% increment over the basal production rate, is made available to the periphery. A wide individual variability was found to exist in both the basal and the glucose-stimulated delivery. They were strongly (P less than 0.001) related to each other in a direct fashion. A first spike of insulin release (107 +/- 12 mU/min) occurred in all the subjects at 2.2 +/- 0.2 min followed, in 16 subjects, by a second spike (38 +/- 6 mU/min), at 11.3 +/- 0.9 min. Two-thirds of the total postglucose insulin output were associated with the initial, oscillatory phase (from 0 to 25 min, on average), and one-third with the "tail" phase (from 25 to 90 min), during which the average delivery rate was 5.0 +/- 0.9 mU/min.m2. The delivery curves were closely (mean squared deviation of 4.5 +/- 0.5 mU/min) reproduced by computer stimulation upon assuming that insulin secretion is a function of both glucose concentration and glucose rate of change. Both the first and the second spike of insulin delivery, but not the total insulin output during the test, showed a significant, positive correlation with the plasma glucose disappearance rate computed between 10 and 60 min. Furthermore, with a time shift of approximately equal to 15 min, a significant relationship between the phases of insulin secretion and the glucose decay rates, computed over corresponding time intervals, was evident throughout the test.     

Melanoma cultures show different susceptibility towards E1A-, E1B-19 kDa- and fiber-modified replication-competent adenoviruses

Replicating adenovirus (Ad) vectors with tumour tissue specificity hold great promise for treatment of cancer. We have recently constructed a conditionally replicating Ad5 AdDeltaEP-TETP inducing tumour regression in a xenograft mouse model. For further improvement of this vector, we introduced four genetic modifications and analysed the viral cytotoxicity in a large panel of melanoma cell lines and patient-derived melanoma cells. (1) The antiapoptotic gene E1B-19 kDa (Delta19 mutant) was deleted increasing the cytolytic activity in 18 of 21 melanoma cells. (2) Introduction of the E1A 122-129 deletion (Delta24 mutant), suggested to attenuate viral replication in cell cycle-arrested cells, did not abrogate this activity and increased the cytolytic activity in two of 21 melanoma cells. (3) We inserted an RGD sequence into the fiber to extend viral tropism to alphav integrin-expressing cells, and (4) swapped the fiber with the Ad35 fiber (F35) enhancing the tropism to malignant melanoma cells expressing CD46. The RGD-fiber modification strongly increased cytolysis in all of the 11 CAR-low melanoma cells. The F35 fiber-chimeric vector boosted the cytotoxicity in nine of 11 cells. Our results show that rational engineering additively enhances the cytolytic potential of Ad vectors, a prerequisite for the development of patient-customized viral therapies.     

西地那非与前列地尔治疗先天性心脏病术后肺动脉高压的疗效对比

目的比较口服西地那非(SIL)与静脉应用前列地尔(PGE1)治疗先天性心脏病(先心病)术后肺动脉高压(PH)的早期疗效。方法24例患者随机分为A、B、C三组:A组先鼻饲SIL0·35mg/kg,后静脉应用PGE120ng/(kg·min);C组顺序相反;B组为对照组。检测用药前后患者血流动力学参数、动脉血气、氧合指标及肺力学参数。结果与B组比较,两组在降低平均肺动脉压(mPAP)、mPAP/有创桡动脉压(mSAP)方面差异均具有统计学意义(P<0·01),SIL较PGE1作用更明显(P<0·05)。SIL可造成患者mSAP下降(P<0·01),但不需干预治疗;PGE1可抑制患者PaO2下降(P<0·05);两组对肺顺应性、呼吸功均无影响。结论两药均能有效降低此类患者肺动脉压力,而SIL口服使用更方便。因此,SIL可作为先心病术后治疗PH的新选择。     

人补体C3功能片段rC3B的克隆、表达和活性鉴定

本研究获取人类补体C3上与补体Ⅲ型受体（CR3）结合的功能区rC3B,并进行了表达、纯化和活性鉴定。用基因扩增法获得rC3B基因,并插入原核表达载体pQE30a,转化大肠杆菌E.coli M15进行表达;用SDS-PAGE电泳检验目的蛋白后以Ni^2＋螯合Sepharose Fast Flow层析进行纯化;用Western blot与单核细胞黏附试验初步确认蛋白活性。结果表明：钓取了人类补体C3的功能片段rC3B,构建了原核表达载体pQE30-rC3B并在E.coli中得了到高效表达;经Ni^2＋固相化的螯合Sepharose Fast Flow亲和层析纯化蛋白后,蛋白纯度达80%;Western blot检测证明rC3B具有抗原性,单核细胞的黏附试验初步确认了纯化后蛋白的活性。结论：确认了人类补体C3的这一活性区域,并获得了该蛋白的功能片段,为深入研究人类补体C3蛋白的功能和应用奠定了基础。