Hepatocyte growth factor: clinical implications in hepatobiliary pancreatic surgery

Hepatocyte growth factor (HGF), originally identified as the most potent mitogen for hepatocytes, is now known to be a cytokine with numerous functions in a wide variety of cells. HGF transduces its various activities via a receptor encoded by the c-met proto-oncogene and coupled to a number of transducers integrating the HGF signal inside the target cells. Extcnsive investigation has revealed that HGF has various beneficial effects, especially for liver. HGF significantly stimulates regeneration in damaged, as well as in normal liver, ameliorates hepatic fibrosis/cirrhosis; and attenuates various types of liver dysfunction in animals. Moreover, the fascinating data on HGF in experimental liver and islet transplantation suggest that the use of HGF may represent a breakthrough for reducing the shortage of donor livers, and increasing the success rate of insulin independence after islet transplantation. Further understanding of the biological significance of HGF, including that in carcinogenesis, will undoubtedly have important clinical implications in hepatobiliary pancreatic surgery.

[The effect of C 1 esterase inhibitor on ischemia: reperfusion injury in the rat brain]

BACKGROUND

Despite the current interest in thrombolytic therapy for acute stroke, ischemia-reperfusion injury remains a potentially hazardous complication. The complement system is thought to play a major role in initiating some of the inflammatory events occurring in the reperfusion injury. This study was conducted to explore the effect of C 1 esterase inhibitor (C 1 INH) on the reperfusion injury in rat middle cerebral artery (MCA) occlusion-reperfusion model.

METHODS

Twenty-nine male Wistar rats were used. Intraluminal MCA occlusion was performed for 60 minutes. Just before the reperfusion, C 1 INH(50 IU/kg, C 1 INH group, n = 15) or saline (control group, n = 14) was administrated. Forty-eight hours after the reperfusion, infarct volume and myeloperoxidase(MPO) activity of the brain were evaluated.

RESULT

Infarct volume and MPO activity were significantly smaller in the C 1 INH group(86.5 +/- 76.8 mm3, 0.38 +/- 0.30 U/g) than in control group(179 +/- 92.8 mm3, 1.37 +/- 0.46 U/g) (p < 0.01).

CONCLUSION

The results of this study provided the first evidence that C 1 INH reduced polymorphonuclear leukocytes(PMN) accumulation and reperfusion damage in the brain.

Activated protein C prevents multiple organ injury following extensive hepatectomy in cirrhotic rats

BACKGROUND/AIMS

Extended hepatectomy for cirrhotic liver in patients with hepatocellular carcinoma often triggers posthepatectomy liver failure. It has been shown that the microcirculatory disturbance caused by microthrombus formation and sinusoidal endothelial cellular injury is one of the causes of post-hepatectomy liver dysfunction. We therefore investigated the effect of activated protein C (APC), a potent antithrombotic serine protease with anti-inflammatory effects, on posthepatectomy liver dysfunction and multiple organ injury in cirrhotic rats.

METHODS/RESULTS

Dimethylnitrosamine-induced cirrhotic rats underwent 70% hepatectomy and received lipopolysaccharide (200 microg/kg) 48 h later to prepare a lethal posthepatectomy acute liver failure model. APC (1500 U/kg), given intravenously 15 min before and 1 h after endotoxin challenge, attenuated liver dysfunction and decreased serum tumor necrosis factor-alpha concentration. APC significantly improved the survival rate of rats at 12 h after endotoxin challenge. Histological examination revealed that APC treatment inhibited not only intrasinusoidal fibrin deposition and massive hepatocellular necrosis but also pulmonary injury and glomerular fibrin deposition. Immunohistochemically, expression of intercellular adhesion molecule-1 on sinusoidal cells and renal glomeruli was decreased in the APC-treated animals.

CONCLUSIONS

APC administration prevented acute liver dysfunction and attenuated multiple organ injury following extended hepatectomy in cirrhotic rats, possibly via anticoagulant and anti-inflammatory effects.

Tissue factor expression in human colorectal carcinoma: correlation with hepatic metastasis and impact on prognosis

BACKGROUND

It has been suggested that tissue factor (TF) plays an important role in tumor metastasis. Its expression in sarcoma cells was reported to up-regulate the vascular endothelial growth factor (VEGF) gene and thereby enhance tumor angiogenesis, which is essential to tumor metastasis. Although many malignant tumors have been reported to express this protein constitutively, recent clinical studies have focused mainly on the correlations among TF expression, tumor progression, and histologic grade. Therefore, to address the role of TF and the underlying mechanism of hematogenous metastasis of colorectal carcinoma, the authors analyzed the correlations among TF expression, hepatic metastasis, and VEGF gene expression in surgical specimens. Furthermore, they analyzed the prognostic significance of TF expression with respect to overall patient survival.

METHODS

Expression of TF and VEGF genes in 67 advanced colorectal carcinoma specimens was studied by immunohistochemistry and Northern blot analysis, respectively. The correlations among TF expression, hepatic metastasis, and other factors were analyzed with univariate and multivariate statistics. Survival rates were calculated using the Kaplan-Meier method.

RESULTS

Univariate and multivariate analyses showed TF expression to be a significant (P = 0.0001) and independent risk factor for hepatic metastasis, whereas a weak but insignificant correlation was observed between TF and VEGF gene expression. The outcomes in the TF positive group were significantly worse in all cases (P = 0.0001) and in the cases without synchronous hepatic metastasis (P = 0.0156).

CONCLUSIONS

Although the precise mechanisms are unknown, TF expression is a suitable indicator of both hepatic metastasis and prognosis for colorectal carcinoma patients.

Tissue factor expression in human colorectal carcinoma: correlation with hepatic metastasis and impact on prognosis

BACKGROUND

It has been suggested that tissue factor (TF) plays an important role in tumor metastasis. Its expression in sarcoma cells was reported to up-regulate the vascular endothelial growth factor (VEGF) gene and thereby enhance tumor angiogenesis, which is essential to tumor metastasis. Although many malignant tumors have been reported to express this protein constitutively, recent clinical studies have focused mainly on the correlations among TF expression, tumor progression, and histologic grade. Therefore, to address the role of TF and the underlying mechanism of hematogenous metastasis of colorectal carcinoma, the authors analyzed the correlations among TF expression, hepatic metastasis, and VEGF gene expression in surgical specimens. Furthermore, they analyzed the prognostic significance of TF expression with respect to overall patient survival.

METHODS

Expression of TF and VEGF genes in 67 advanced colorectal carcinoma specimens was studied by immunohistochemistry and Northern blot analysis, respectively. The correlations among TF expression, hepatic metastasis, and other factors were analyzed with univariate and multivariate statistics. Survival rates were calculated using the Kaplan-Meier method.

RESULTS

Univariate and multivariate analyses showed TF expression to be a significant (P = 0.0001) and independent risk factor for hepatic metastasis, whereas a weak but insignificant correlation was observed between TF and VEGF gene expression. The outcomes in the TF positive group were significantly worse in all cases (P = 0.0001) and in the cases without synchronous hepatic metastasis (P = 0.0156).

CONCLUSIONS

Although the precise mechanisms are unknown, TF expression is a suitable indicator of both hepatic metastasis and prognosis for colorectal carcinoma patients.

[Birth cohort analysis of obesity in an occupational setting]

PURPOSE

The purpose of this study was to analyze the transition of body mass index (BMI) by birth cohort and to determine the relationship between BMI and high blood pressure, for the health management of workers in an industry.

SUBJECTS AND METHODS

The eligible study subjects were 3,043 male workers at printing and papermaking plants who were 20 to 49 years of age in 1986 and whose annual health checkup information was available for both 1991 and 1996. First, we analyzed the transition of BMI by 5-year birth cohort. Second, we analyzed the relationship between BMI and high blood pressure (systolic blood pressure > = 140 mmHg or diastolic blood pressure > = 90 mmHg) using multiple logistic regression models. In this analysis, we excluded 596 subjects who were diagnosed as having high blood pressure in 1986 and 17 subjects whose alcohol drinking habits were unknown. Consequently, we had 2,430 study subjects.

RESULTS

(1) All the birth cohorts showed that the proportion of obese subjects (BMI > = 26.4) became higher as age advanced. The proportion was higher for younger cohort. (2) By multiple logistic regression models, age at the beginning of the study, BMI, change of BMI in 5 or 10 years, and alcohol drinking habits were related to the risk of having high blood pressure.

CONCLUSION

In the health management of workers, it is necessary to evaluate the risk by birth cohort. Also, we consider that we need to initiate obesity counseling before the workers become 30 years of age.

Pretreatment with soluble thrombomodulin prevents intrasinusoidal coagulation and liver dysfunction following extensive hepatectomy in cirrhotic rats

The major cause of posthepatectomy liver dysfunction is supposed to be microcirculatory disturbance caused by imbalance of intrasinusoidal coagulation equilibrium. Thrombomodulin (TM) is a potent anticoagulant expressed on the endothelial cell surface that regulates the coagulation system by binding thrombin and accelerating the thrombin-catalyzed activation of protein C. Therefore, we examined the effect of soluble TM purified from human urine (UTM) on intrasinusoidal coagulation in cirrhotic rats. Dimethylnitrosamine-induced cirrhotic rats underwent 70% hepatectomy and received endotoxin 48 h after. UTM or vehicle alone was intravenously administered to each rat 30 min before endotoxin injection. UTM treatment attenuated the increases in cytosolic enzymes and serum hyaluronic acid level. The UTM supply improved the survival rate of the rats at 12 h after endotoxin challenge. Histologically, intrasinusoidal fibrin depositions and massive hepatocellular necrosis observed in control rats were scarcely found in UTM-treated rats. Immunohistochemical examination revealed that marked TM stains in sinusoidal endothelial cells were well preserved in UTM-treated rats. In conclusion, UTM administration prevented intrasinusoidal fibrin depositions and attenuated posthepatectomy liver dysfunction in cirrhotic rats.

Hepatocyte growth factor supply accelerates compensatory hypertrophy caused by portal branch ligation in normal and jaundiced rats

BACKGROUND

Hepatocyte growth factor (HGF), first identified as the most potent mitogen for hepatocytes, significantly stimulates liver regeneration after hepatectomy. In this report, we examined whether HGF is also useful in accelerating compensatory hypertrophy caused by portal branch ligation in normal and jaundiced rats.

MATERIALS AND METHODS

Normal and reversible obstructive jaundiced rats underwent portal ligation of the left lateral and median branches, which supply approximately 70% of the total volume of the liver. Simultaneously, the animals were continuously treated with either recombinant human HGF (rhHGF) or vehicle alone via an intraperitoneally implanted osmotic pump. Two and four days after portal ligation, the degree of compensatory hypertrophy in unoccluded lobes was examined by measuring the wet weight ratios of the unoccluded lobes to the whole liver and the 5-bromo-2'-deoxyuridine labeling index of hepatocytes in each group.

RESULTS

The HGF treatment significantly increased the wet weight ratios and the DNA synthesis in nonoccluded lobes 2 and 4 days after portal ligation in both normal and jaundiced rats. Moreover, rhHGF supply promptly decreased serum total bilirubin level in jaundiced rats.

CONCLUSIONS

Continuous rhHGF administration not only accelerates compensatory hypertrophy in normal and jaundiced rats but also ameliorates hyperbilirubinemia in jaundiced rats.

Morphologic alteration of hepatocytes and sinusoidal endothelial cells in rat fatty liver during cold preservation and the protective effect of hepatocyte growth factor

BACKGROUND

Fatty liver grafts are considered to be one of the main factors of primary nonfunctioning graft in transplantation. We investigated here, the hepatic damage during cold preservation in a rat fatty liver model by ultrastructural observation, and examined the effect of human recombinant hepatocyte growth factor (hrHGF) on amelioration of the cold-preserved graft condition.

METHODS

Wistar rats were fed a choline-deficient diet (CDD) for 7 days. Livers were stored in cold University of Wisconsin (UW) solution for 0, 4, and 24 hr. We evaluated the ultrastructural alteration of the hepatocytes, sinusoidal architecture, and endothelial cells (SECs) by scanning and transmission electron microscopy. Ex vivo, we measured alanine aminotransferase (ALT) in first effluent as an index of hepatocyte injury and the hyaluronic uptake rate (HUR) as that of SEC damage. We injected hrHGF into rats fed CDD for 7 days through the portal vein and also added it to the UW solution to determine whether or not the agent ameliorated the hepatic damage in cold-preserved fatty livers.

RESULTS

In rats fed CDD for 7 days, the lesion occupied by fat deposits appeared to enlarge with the duration of cold preservation leading to the disarrangement of sinusoidal architecture. Furthermore, sinusoidal endothelial damage, in which gaps, blebs, microvilli, and sinusoid denudation were detected, appeared to be more severe in these livers than in the corresponding control livers. ALT significantly increased in the 4-hr cold-preserved livers of rats fed CDD for 7 days. HUR decreased with 4-hr cold preservation and/or with CDD feeding. Administration of hrHGF prevented the expansion of fatty droplets and reduced SEC injury as detected by morphological observations. Increase of ALT in first effluent was inhibited to about one fourth the level observed in the 4-hr cold-preserved livers of rats fed CDD. Moreover, HUR significantly increased with the pretreatment of hrHGF.

CONCLUSION

The hepatic injury in both hepatocytes and SECs in cold-preserved fatty liver graft developed more rapidly and severely than in the corresponding controls and demonstrated a protective effect of hrHGF.

Hepatocyte growth factor prevents lipopolysaccharide-induced hepatic sinusoidal endothelial cell injury and intrasinusoidal fibrin deposition in rats

BACKGROUND

Acute endotoxemia is known to cause activation of Kupffer cells as well as serious injury in parenchymal and nonparenchymal cells in the liver. We have recently shown that a continuous recombinant hepatocyte growth factor (rHGF) supply prevents lipopolysaccharide (LPS)-induced liver injury in rats. As an attempt to elucidate the mechanism, here we investigate the cytoprotective effect of rHGF on sinusoidal endothelial cells (SECs) in LPS-induced liver injury in rats.

MATERIALS AND METHODS

In order to supply rHGF continuously to the liver, syngenic rat fibroblasts genetically modified to secret rat rHGF were implanted in the spleen. Fourteen days after cell implantation, we injected LPS intravenously and evaluated SEC damage histologically and blood chemically.

RESULTS

Phosphotungstic acid-hematoxylin staining revealed that rHGF treatment greatly attenuated intrasinusoidal LPS-induced fibrin deposition. The ultrastructural changes in SECs caused by LPS administration in control rats were barely detectable in rHGF-treated rats. Blood chemical analyses showed that rHGF potently suppressed the LPS-induced increase in serum hyaluronic acid and transaminase levels.

CONCLUSIONS

Our results indicate an important role for HGF in SEC protection in vivo and would suggest a novel therapeutic strategy for liver diseases with SEC injury.

Portal branch ligation with a continuous hepatocyte growth factor supply makes extensive hepatectomy possible in cirrhotic rats

In a cirrhotic liver, the regenerative ability and specific functions are so impaired that excessive resection easily complicates postoperative liver dysfunction, which frequently leads to life-threatening multiple-organ failure. Hepatocyte growth factor (HGF), first identified as the most potent stimulator of DNA synthesis in primary hepatocytes, not only stimulates liver regeneration, but also accelerates hepatic function, improves fibrosis, and protects liver cells against injury. Therefore, we investigated the efficacy of preoperative portal branch ligation (PBL) (which can induce compensatory hypertrophy of the unaffected lobes) combined with a continuous HGF supply in the performance of extensive hepatectomy in cirrhotic rats. Cirrhosis was induced by intraperitoneal injections of dimethylnitrosamine (DMN) three times per week for 3 weeks. Five days after the last injection, when 70% hepatectomy is lethal, the rats underwent portal ligation of the left lateral and median branches (corresponding to approximately 70% of the total volume of the liver). Simultaneously, they were continuously treated with either recombinant human HGF (rhHGF) or vehicle from an intraperitoneally implanted osmotic pump. Four days after the portal ligation, the occluded lobes were resected. The HGF treatment rapidly increased both the wet weight of the unoccluded lobes and the hepatocellular DNA synthesis. The blood chemical analysis indicated that HGF significantly suppressed the posthepatectomy liver dysfunction. Most importantly, the HGF treatment markedly improved the survival rate of the rats at 48 hours after the major hepatectomy. In conclusion, PBL combined with a continuous HGF supply makes extensive hepatectomy possible in cirrhotic rats, mainly by promoting the hypertrophy of the unaffected lobes.

Hepatocyte growth factor promotes liver regeneration with prompt improvement of hyperbilirubinemia in hepatectomized cholestatic rats

BACKGROUND

In hepatectomy for patients with liver cirrhosis or cholestasis, prolonged postoperative hyperbilirubinemia is a troublesome complication and, if uncontrolled, often leads to life-threatening hepatic failure. Hepatocyte growth factor (HGF), first identified as the most potent mitogen for primary hepatocytes, has been shown to have multiple biological properties on liver, including mitogenic, antifibrotic, and cytoprotective activities. This study investigated the beneficial effects of a perioperative HGF supply to jaundiced liver after hepatectomy in rats.

MATERIALS AND METHODS

As a model of jaundiced liver, we used an alpha-naphtylisocyocyanate (ANIT)-induced intrahepatic cholestasis model. Forty-eight hours after intraperitoneal injection of ANIT (75 mg/kg), when the total serum bilirubin level was moderately increased, a 70 % hepatectomy was performed. Human recombinant HGF (250 microgram/kg) (n = 15) or vehicle alone (n = 15) was intermittently administered to the rats 12 h before surgery and every 12 h after that until sacrifice.

RESULTS

Perioperative HGF treatment effectively accelerated hepatocellular DNA synthesis of cholestatic liver followed by increase in the regenerated liver weight. Moreover, HGF supply promptly improved hyperbilirubinemia within 24 h after surgery. Histological examination revealed that HGF administration attenuated periportal inflammation and formation of bile duct obstructions. Postoperative serum concentrations of tumor necrosis factor-alpha, a representative inflammatory cytokine, were not altered by HGF treatment.

CONCLUSIONS

Perioperative HGF supply not only promotes liver regeneration but also ameliorates hyperbilirubinemia in hepatectomized cholestatic rats. This mode of HGF treatment may be clinically useful for hepatectomy in patients with cholestasis.

Perioperative continuous hepatocyte growth factor supply prevents postoperative liver failure in rats with liver cirrhosis

Insufficient regeneration and dysfunction of cirrhotic liver following partial hepatectomy often make the resection extremely vulnerable to postoperative liver failure, which frequently leads to multiple organ failure. Hepatocyte growth factor (HGF), first identified as the most potent mitogen for primary hepatocytes, not only stimulates hepatic regeneration but also accelerates liver function, improves fibrosis, and protects liver cells against injury. Therefore, we investigated the ability of a continuous supply of HGF to cirrhotic livers to prevent postoperative liver failure in rats. After liver cirrhosis was induced in 40 rats by the intraperitoneal injection of dimethylnitrosamine (DMN) for 4 weeks, fibroblasts genetically modified to secret rat HGF or control fibroblasts were implanted in the spleens of 20 syngenic rats per group to supply HGF continuously and directly to the cirrhotic livers. Two weeks after the implantation, all rats underwent a 30% hepatectomy. The HGF administration significantly improved liver fibrosis at the time of operation, attenuated the postoperative hepatic damage on histological examination, markedly accelerated the liver regeneration at 24 h after the hepatectomy. The blood chemical analysis indicated that HGF significantly suppressed postoperative liver failure. Most importantly, the HGF treatment significantly improved the survival rate of the rats at 48 h after the hepatectomy. The perioperative continuous supply of HGF from the spleen effectively prevented liver failure following resection of cirrhotic livers in rats.

Continuous hepatocyte growth factor supply prevents lipopolysaccharide-induced liver injury in rats

We present a rat model in which continuous supply of hepatocyte growth factor (HGF) prevents liver injury induced by carbon tetrachloride (CCl4) and E. coli 011:B4 lipopolysaccharide (LPS). Rat fibroblasts genetically modified to secrete rat HGF were implanted in syngenic rat spleen 7 days before administration of the hepatotoxins. Rats with HGF-secreting fibroblasts in the spleen showed a dramatic resistance to CCl4- and LPS-induced liver injury. In the LPS-induced liver injury model, blood chemical analysis revealed that the increase in serum glutamic oxalacetic transaminase level and the decrease in blood sugar level were remarkably suppressed in rats with HGF-secreting cells in the spleen. Most importantly, their survival rate was greatly improved compared to other control groups of rats. Thus our results indicate a new role of HGF in liver protection during endotoxemia and convey important clinical implications for developing new therapeutic modalities in the treatment of liver failure caused by endotoxemia.

Hematogenous spreading of hepatocellular carcinoma cells: possible participation in recurrence in the liver

To detect hepatocellular carcinoma (HCC) cells in the circulating peripheral blood, we previously designed a highly sensitive reverse-transcription polymerase chain reaction (RT-PCR) method targeting alpha-fetoprotein (AFP) messenger RNA (mRNA). Using this method, we analyzed peripheral blood of in- and out-patients bearing HCC for 2 months consecutively and examined the outcome thereafter. All 11 patients with recurrence either in the liver alone or in both the liver and the lung were positive for AFP mRNA. Among 10 recurrence-free patients, 2 patients were AFP mRNA-negative and remained recurrence-free during a period of 22 months observed. Four of 8 AFP mRNA-positive, recurrence-free patients developed a clinically evident recurrence in the liver after 2 to 16 months. Seven of 8 preoperative patients were already positive for AFP mRNA and the remaining negative patient became positive during surgery. Four of 6 preoperatively positive and still-alive patients had recurrence in the liver after 2 to 9 months. None of the HCC-negative patients were positive for AFP mRNA. We actually found an AFP protein-positive cell in peripheral blood obtained from one of the AFP mRNA-positive patients by immunostaining. The present results suggest that circulating HCC cells may have some relationship with the recurrence of HCC in the liver.

Rotational obstruction of nondominant vertebral artery and ischemia. Case report

A 70-year-old man presented with repeated vertebrobasilar insufficiency for 3 years. Four-vessel angiography revealed complete occlusion of the nondominant left vertebral artery on head turning to the right. Three-dimensional computerized tomography angiography demonstrated atlantoaxial joint dislocation when the head was turned to the right, in accordance with simultaneous occlusion of the left vertebral artery caused by stretching of the artery at C1-2. After posterior fixation of C1-2 by a Halifax interlaminar fixation system, the patient had no further episodes. Hemodynamic function associated with nondominant vertebral artery occlusion contributed to the symptoms in this case.

Continuous HGF supply from HGF-expressing fibroblasts transplanted into spleen prevents CCl4-induced acute liver injury in rats

Hepatocyte growth factor (HGF), first identified as a potent mitogen for mature hepatocytes, has been reported to have various activities. We investigated protective effect of continuous HGF supply on carbon tetrachloride (CCl4)-induced acute liver injury in rats. We transfected immortalized but not tumorigenic rat fibroblasts (Rat-1) with an expression plasmid containing the human HGF cDNA and established several cell lines expressing HGF. The biological activity of HGF produced by these cell lines was confirmed by its mitogenic effect on rat hepatocytes in vitro. Either one of the high-HGF-producer cell lines or parental Rat-1 cell line was transplanted into a syngenic rat spleen. Twelve days after transplantation, each rat was intraperitoneally injected with CCl4 and sacrificed 48 h after CCl4 injection. In rats with continuous HGF supply significantly lower serum glutamic-pyruvic transaminase (GPT) level was observed compared to its marked elevation in control rats and the degree of hepatocyte damage was slight on histological analysis. These results indicate that continuous HGF supply effectively inhibits CCl4-induced acute liver injury and may suggest the possibility that this system would be useful on various liver diseases.

The essential role of endogenous IFN alpha/beta in the anti-metastatic action of sensitized T lymphocytes in mice injected with Friend erythroleukemia cells

Adoptive transfer of splenic T lymphocytes from DBA/2 mice immunized against Friend erythroleukemia cells (FLC) inhibited the development of visceral metastases and increased the survival time of DBA/2 mice challenged i.v. with parental FLC 24 hr to 2 months later. Immune spleen cells were ineffective in mice pre-treated with potent neutralizing antibody to mouse IFN alpha/beta (but not to IFN gamma), demonstrating the essential participation of endogenous IFN alpha/beta in the inhibitory action of immune T lymphocytes against FLC metastases. These findings suggest that the reported inability of immune T lymphocytes to exert an anti-FLC effect in immunodeficient DBA/2 mutant beige (bg/bg) mice (unless these mice had also been treated with IFN alpha/beta), may have been due to lower levels of endogenous IFN alpha/beta in DBA/2 bg/bg mice than in normal DBA/2+/bg mice. Experimental results in support of this hypothesis are presented.

COS cell expression cloning of Pfg377, a Plasmodium falciparum gametocyte antigen associated with osmiophilic bodies

We report the deduced protein sequence and preliminary characterization of Pfg377, a novel sexual stage antigen of Plasmodium falciparum. An initial cDNA clone (Pfg377-1) encoding the N-terminal 755 amino acids of Pfg377 was isolated by transfecting a 3D7 gametocyte cDNA library into COS7 cells and selecting using a pool of anti-Pfs230 monoclonal antibodies. The protein encoded by Pfg377-1 included an N-terminal hydrophobic signal sequence, but no apparent transmembrane anchor. Instead, the particular cDNA clone selected was fused in-frame at its 3' end with the coding sequence for the human decay acceleration factor membrane anchor, which had been deliberately placed downstream of the vector polylinker in order to attach potential fusion proteins onto the COS cell surface. Northern blots probed with the Pfg377-1 cDNA demonstrated cross-hybridization to a single approximately 9.5-kb transcript, which was present only in sexual stages, and not in a sexual stages. DNA hybridization was used to obtain a series of overlapping genomic clones which collectively yielded the complete DNA sequence for Pfg377. There are no introns within the gene, which contains a 9360-bp open reading frame and encodes a 377-kDa protein. The Pfg377 protein is highly hydrophilic, and has an essentially non-repetitive structure, with only four very limited regions of tandem repeats. The Pfg377 gene resides on chromosome 12, and immunoelectron microscopy with two different anti-Pfg377 polyclonal antisera raised against two separate recombinant sub-fragments of the protein both indicated that the antigen is located in electron-dense organelles of the gametocytes--the osmiophilic bodies--which are proposed to play a role in parasite emergence from the erythrocyte during gametocyte maturation in the Anopheles mosquito midgut. Although it was selected with anti-Pfs230 antibodies, comparison of the sub-cellular locations and protein sequences of Pfg377 and Pfs2 show them to be completely distinct antigens. We hypothesize that Pfg377-1 was initially isolated because it expresses an epitope which is recognized by (i.e., cross-reacts with) one of the anti-Pfs230 monoclonal antibodies used to select the original transfected COS cells.

[Surveillance of hyperlipidemia among young adults in an occupational setting]

This study was conducted to contribute to the improvement of occupational health surveillance. The subjects of the study were 461 young male workers born between April 1959 to March 1969, who worked at two plants in Tokyo, and who do not usually undergo examination of blood lipid levels at a routine health check-up program. The screening procedure was mainly based on the second report of the National Cholesterol Education Program Expert Panel (Adult Treatment Panel, ATP II). The proportion of the subjects with low HDL-cholesterol level (< 35 mg/dl) was 5.2% for workers in their late twenties (W20) and 8.4% for those in their early thirties (W30). For high LDL-cholesterol (130+ mg/dl), the proportion (underestimated due to non-fasting blood collection) was 7.2% for W20 and 13.5% for W30, and the difference was statistically significant (p < 0.05). Among subjects with low HDL, the proportion of subjects with total cholesterol (TC) being < 200 mg/dl was 94% (15/16) for W20 and 54% (7/13) for W30. This implies that it is difficult to detect subjects with low HDL from values for TC only especially among W20. Hence it is useful to examine HDL in combination with TC. Among subjects with TC being 200-239 mg/dl, the proportion (underestimated) of the subjects with high LDL was 40% for W20 and 26% for W30, and ATP II procedure would fail to incorporate most of them into a treatment program. Thus, accurate estimation of LDL is necessary for subjects with TC being 200+ mg/dl. Relationships of high HDL (60+ mg/dl) to exercise as well as low HDL to obesity (p < 0.05) were found among both age groups. The high prevalence of LDL and HDL abnormality found among the study subjects would imply that it is necessary to initiate evaluation of hyperlipidemia at younger ages and also ATP II procedure needs to be modified for proper surveillance.

Highly-sensitive identification of alpha-fetoprotein mRNA in circulating peripheral blood of hepatocellular carcinoma patients

In order to capture hepatocellular carcinoma (HCC) cells in circulating peripheral blood, we made analysis to see if alpha-fetoprotein (AFP) mRNA exists in the peripheral blood obtained from patients with HCC and also, as a control, from hepatitis-viral-marker-positive patients without HCC and a healthy volunteer. As the number of HCC cells in peripheral blood and the quantity of AFP mRNA are expected to be very small, the analysis was performed by the reverse transcription followed by an original three-step polymerase chain reaction. By this highly-sensitive method, 5 of 7 HCC patients were positive for AFP mRNA. These 5 positive patients consisted of three with clinically apparent recurrence, one preoperative patient with tumor thrombus in the portal vein and one recurrence-free patient who developed clinically detectable recurrence three months after this analysis. Neither 4 patients with positive viral markers nor a healthy volunteer was positive. The results suggest that detection of AFP mRNA from HCC patients' peripheral blood by our highly-sensitive RT-PCR may be a practical and powerful tool to diagnose the preoperative spreading of HCC and to monitor its recurrence.

Local and systemic response of mice to interferon-alpha 1-transfected Friend leukemia cells

DBA/2 mice were injected subcutaneously with an interferon (IFN)-alpha/beta-resistant line of Friend erythroleukemia cells (FLC) transfected with the mouse IFN-alpha 1 gene. These tumor cells produced IFN constitutively, and mice had persistently high levels of IFN in the circulation. We examined the IFN-induced host mechanisms responsible for the local inhibition of growth of these IFN-alpha-transfected FLC and some of the unusual systemic effects of constant interferonemia such as extramedullary hematopoiesis in the liver, an increase in myeloid cells in the spleen, and persistently elevated splenic natural killer (NK) cell activity. In addition, both DBA/2 +/bg and beige mice developed a rapid and specific resistance to intravenous challenge with parental FLC. In previous experiments DBA/2 beige mice could not be protected by exogenous IFN-alpha/beta. The differences in the response of mice to the constitutive production of IFN-alpha by IFN-alpha-transfected tumor cells and their response to exogenous IFN is discussed in terms of the effects of IFN on the host and of antitumor therapy.

Alteration in the fluorescence polarization of rat plasma and liver cell membranes following bile duct ligation in rats

The fluorescence polarization levels of liver cell membranes and plasma were analyzed to determine membrane fluidity following bile duct ligation (BDL) in rats. Fluorescence polarization was measured with a spectrofluorophotometer equipped with polarizers, using 1,6-diphenyl-1,3,5-hexatrien (DPH) as a probe. After bile duct ligation, liver cell membrane fluidity decreased significantly for up to 14 days after surgery (P < 0.001 on 3rd and 7th days). The polarization of the plasma in rats with BDL slightly but significantly increased compared to the levels in the control animals over the 14-day period following BDL. In addition, a small but significant correlation in the polarization levels between plasma and liver cell membranes (r = 0.362, P < 0.02) was observed. The co-incubation of BDL plasma with normal liver cell membranes resulted in a decrease in membrane fluidity, which suggested that BDL rat plasma had a direct effect on membrane fluidity. After a 70% hepatectomy, the polarization of the membranes from remnant livers in the BDL rats remained elevated relative to the sham-operated controls. It is thus concluded that the membrane fluidity of the livers in BDL rats decreases following bile duct ligation and does not increase after a 70% hepatectomy, presumably due to the increased plasma level of bilirubin.

Significance of altered fluidity of plasma membranes of the liver and kidney in rats with sepsis

The present study was conducted to investigate changes in plasma membrane fluidity of the liver and kidney in sepsis, which is the main cause of multiple organ failure. Male Wistar rats weighing 200-250 g were used in all experiments. Sepsis was induced by cecal ligation and puncture. As a control, a sham operation was performed. The time course of plasma membrane fluidity of the liver and the renal cortex in septicemic rats or in controls was studied. To evaluate the fluidity, fluorescence polarization was measured using 1,6-diphenyl-1,3,5-hexatriene. The fluorescence polarization values of liver plasma membranes increased after cecal ligation and puncture: 0.183 +/- 0.004 (mean +/- SEM), 0.194 +/- 0.008, 0.206 +/- 0.003, and 0.210 +/- 0.002 at 0, 24, 48, and 72 hr, respectively. Corresponding values for membranes of the renal cortex increased in a similar fashion. To determine whether factors involved in cell membrane damage exist in blood, the direct effects of lipopolysaccharide (LPS), platelet-activating factor (PAF), and serum from normal rats or from septicemic rats on membrane fluidity were studied. The fluorescence polarization of plasma membranes of the liver or renal cortex to which septicemic rat serum was added was higher than that of plasma membranes to which normal rat serum was added. The fluorescence polarization of liver plasma membranes was increased by LPS, but that of plasma membranes of the renal cortex was slightly decreased. In addition, the fluorescence polarization of liver plasma membranes was increased by PAF, but that of plasma membranes of the renal cortex was decreased.(ABSTRACT TRUNCATED AT 250 WORDS)