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PURPOSE: Airline pilots are exposed to magnetic fields generated by the aircraft's electrical and electronic systems. The purpose of this study was to directly measure the flight deck magnetic fields to which commercial airline pilots are exposed when flying on different aircraft types over a 75-hour flight-duty month.METHODS: Magentic field measurements were taken using personal dosimeters capable of measuring magnetic fields in the 40-800 Hz frequency range. Dosimeters were carried by either the Captain or the First Officer on Boeing 737/200, Boeing 747/400, Boeing 767/300ER, and Airbus 320 aircraft. The data were analyzed by aircraft type, with statistics based on block hours. Block hours begin when the aircraft departs the gate prior to take off and end when the aircraft returns to the gate after landing.RESULTS: Approximately 1008 block hours were recorded at a sampling rate of 3 seconds. Total block time exposure to the pilots ranged from a harmonic geometric mean of 6.7 milliGauss (mG) for the Boeing 767/300ER to 12.7 mG for the Boeing 737/200.CONCLUSIONS: Measured flight deck magnetic field levels were substantially above the 0.8 to 1 mG level typically found in the home or office and suggest the need for further study to evaluate potential health effects of long-term exposure.

Background & Aims: alpha-Fetoprotein (AFP) is a tumor-associated protein that is frequently expressed at high levels in hepatocellular carcinoma (HCC). The aim of the study was to characterize self-reactive cytotoxic T lymphocytes (CTLs) directed against murine AFP (mAFP) after DNA-based immunization in mice., Methods: To study CTL responses, mAFP-expressing recombinant vaccinia viruses were generated. An HCC tumor model was established in C57L/J mice by injection of syngeneic endogenously mAFP-expressing Hepa1-6 cells., Results: Gene gun and intramuscular coimmunizations of DNA expression vectors encoding mAFP with plasmids encoding murine interleukin (IL)-12, granulocyte-macrophage colony-stimulating factor, or IL-18 induced weak CTL activity against mAFP in different mouse strains. Some mice developed anti-mAFP antibody responses, suggesting breaking of immunologic ignorance. No hepatocyte damage was detectable despite low-level endogenous hepatic mAFP expression. Therapeutic immunizations of mice bearing mAFP-expressing murine HCCs induced partial regression of tumors. A significant survival benefit was observed in mice immunized with mAFP expression vector DNA but not in untreated mice or in mice immunized with mock/cytokine plasmid DNA., Conclusions: The data show that AFP may be used as a potential self tumor antigen to induce CTL and CD4(+) T cell-mediated regression of AFP-expressing HCC by DNA-based immunization.

PURPOSE: The purpose of this study is to assess the patterns of geographic variation of the following pulmonary diseases: tuberculosis (TB), lung cancer (LC), berylliosis (BR), sarcoidosis (SR), and asthma (AS).METHODS: Hospitalization rates for the five diseases were calculated for the 46 South Carolina (SC) counties from 1985-1995. Variation in rates was assessed by county, region, and urban/rural status using analysis of variance. SC was divided into 4 regions, according to proximity to the coastline and to physiographic characteristics. Region 1 comprised counties in the western-most part of the state, and region 4 comprised the counties closest to the coastline. SC was also divided into 5 population density settings: extreme rural (<15,000), rural (15,000-30,000), middle-size (30,000-50,000), middle-urban (50,000-100,000) and urban (>100,000). Statistical analyses were performed with SAS Version 8.RESULTS:Table 1The rates of SR, TB, and BR were significantly higher in the coastal region. In contrast, no coastal pattern was detected by population density.CONCLUSIONS: The consistent association of SR, TB, and BR with geographical region, as opposed to the inconsistent association with population density, suggests that environmental factors may be involved in these pulmonary diseases. These results demonstrate the need for further analysis of the relationship between socio-economic, behavioral, and environmental factors and the development of these diseases.

PURPOSE: Fetal and early life events have been associated with diseases that develop later in life. Low birth weight and the adult onset of hypertension, coronary heart disease, cerebrovascular disease, and non-insulin dependent diabetes have been identified. As well, associations with breast, ovarian, and prostate cancer to high birth weight have been found. An assessment of birth weight and cancer incidence was conducted in a cohort of black and white residents under the age of 46 years.METHODS: Cases were obtained from the Savannah River Region Health Information System cancer registry incident cases (1991-1995) and were limited to South Carolinians born in 1950 and later. Controls were obtained from birth certificate records by choosing the next two records after a cancer case record that matched on year of birth, race, and sex. Results were obtained for 117 cancer cases and 238 controls.RESULTS: After examining the birth distribution, the births were split into two groups based on mean birth weight among controls (3215 grams). Conditional logistic regression (CLR) showed that individuals with higher birth weights (> = 3215 g) were 1.65 (95% CI = 1.03-2.64) times more likely to be cancer cases than those with lower birth weights. When weights were categorized into 500 g increments, a CLR Score statistic showed there was a significant trend (p = 0.0006) of increasing proportion of cancer cases with increasing birth weight. Eight out of the eight cases of lymphoma had birth weights greater than 3579 g.CONCLUSIONS: The results of this preliminary study suggest that cancer incidence among the young may be associated with higher birth weights. One possible reason for this finding, which requires further investigation, might be that larger infants are exposed to higher levels of hormones and/or growth factor than smaller infants in utero that might increase the risk of certain cancers later in life. This may be suggestive of possible environmental factors affecting early growth. These findings support the need for additional study of this association.

Gene therapy using vector-mediated transfer of prodrug activating genes is a promising treatment approach for malignant tumors. As demonstrated recently, the novel prodrug activating gene coding for rabbit cytochrome P450 4B1 (CYP4B1) is able to induce tumor cell death at low micromolar concentrations in glioblastoma cells after treatment with the prodrug 4-ipomeanol (4-IM) in vitro and in vivo. The rabbit CYP4B1 converts this prodrug and other furane analogs and aromatic amines, such as 2-aminoanthracene, to highly toxic alkylating metabolites, whereas the human isoenzyme exhibits only minimal enzymatic activity. In the present study, the cDNA encoding rabbit CYP4B1 was used for pharmacogene therapy of hepatocellular carcinoma (HCC). Cell clones derived from the human HCC cell lines Hep3B, HuH-7, and HepG2 and stably expressing the chimeric protein CYP4B1-EGFP (the CYP4B1 coding sequence fused to the enhanced green fluorescent protein (EGFP) gene) were selected. HCC clones expressing EGFP served as controls. 4-IM rapidly induced tumor cell death in CYP4B1-EGFP-expressing clones at low concentrations (a 50% lethal dose of between 0.5 and 2 microg/mL). No signs of toxicity were found in control cells expressing EGFP even at high prodrug concentrations (20 microg/mL). Cell death occurred by apoptosis and was independent of functional p53. A pronounced direct bystander effect was observed in Hep3B cells, whereas bystander HepG2 and HuH-7 cells were highly resistant to toxic 4-IM metabolites. These results demonstrate that the CYP4B1/4-1M system efficiently and rapidly induces cell death in HCC cells, and that a cell line-specific mechanism may exist that limits the extent of the bystander effect of this novel prodrug activating system.

We developed a specific adenoviral gene delivery system with monoclonal antibody (mAb) AF-20 that binds to a 180 kDa antigen highly expressed on human hepatocellular carcinoma (HCC) cells. A bifunctional Fab-antibody conjugate (2Hx-2-AF-20) was generated through AF-20 mAb crosslinkage to an anti-hexon antibody Fab fragment. Uptake of adenoviral particles and gene expression was examined in FOCUS HCC and NIH 3T3 cells by immunofluorescence; beta-galactosidase expression levels were determined following competitive inhibition of adenoviral CAR receptor by excess fibre knob protein. The chimeric complex was rapidly internalized at 37 degrees C, and enhanced levels of reporter gene expression was observed in AF-20 antigen positive HCC cells, but not in AF-20 antigen negative NIH 3T3 control cells. Targeting of recombinant adenoviral vectors to a tumor associated antigen by a bifunctional Fab-antibody conjugate is a promising approach to enhance specificity and efficiency of gene delivery to HCC., (Copyright 2000 Academic Press.)

Expression of viral or bacterial enzymes in tumor cells to convert nontoxic prodrugs into highly toxic metabolites is an attractive gene-therapeutic approach for the treatment of hepatocellular carcinoma (HCC). The Escherichia coli purine nucleoside phosphorylase (PNP) converts purine analogs into freely diffusible metabolites, which are highly toxic to dividing and nondividing cells. We investigated the antitumor effects of PNP in the human HCC cell lines, HepG2, Hep3B, and HuH-7, and performed a comparison with herpes simplex thymidine kinase (TK). The genes for PNP, TK, and enhanced green fluorescent protein (EGFP) were delivered to HCC cells by identical adenoviral vectors. Fludarabine and ganciclovir (GCV) served as prodrugs for PNP and TK, respectively. Expression of PNP highly sensitized HCC cells to fludarabine treatment. Fludarabine concentrations between 0.5 and 1 microg/mL killed 100% of the cells expressing PNP with no detectable toxicity in control cells expressing EGFP. Expression of PNP in as few as 10% of HCC cells induced efficient killing of most bystander cells. Expression of TK followed by GCV treatment produced a potent growth inhibition but failed to kill all TK-expressing HCC cells. More importantly, the TK system exhibited a lower degree of bystander effect. Adenoviral delivery of PNP followed by fludarabine administration prevented subcutaneous and intrahepatic tumor formation in nude mice and was also effective for the treatment of established tumors. These results demonstrate the potential of the PNP/fludarabine system for the treatment of HCC.

In 1991, an increased rate of childhood leukaemia was reported from the small northern German community of Elbmarsch, which is located on the banks of the River Elbe opposite the Kruemmel nuclear power plant. Owing to the fact that the increase occurred six years after the start-up of the plant, radioactive discharges were suspected as being implicated in the development of the cases. Previous investigations have failed to identify any exposure which might be associated with the cluster. Nonetheless, concern regarding the increased tritium burden in the environment remains. To further assess the impact of tritium releases to the environment upon population cancer rates, the releases and leukaemia rates at the Savannah River site, USA, were compared with the Kruemmel site. Based on the data from 1991 to 1995, the incidence of childhood leukaemia in the vicinity of the Savannah River site was non-significantly less than expected compared with the significantly higher than expected rates close to the German plant. In contrast, tritium releases from the Savannah River site exceed those from the Kruemmel site by several orders of magnitude. The results of this observational study suggest that factors other than environmental tritium releases are associated with the increased number of leukaemia cases near the Kruemmel site.

Geographic patterns of sarcoidosis have been detected and studied on a global scale. However, the associations between these disease patterns and population characteristics have not been determined. The authors studied the geographic pattern of sarcoidosis in South Carolina and its relation to socioeconomic status (SES) and health status indicators. Hospitalization rates for the period 1985-1995 were used as geographic indicators of sarcoidosis. Rates were assessed for the 46 counties in South Carolina, adjusting for differences in SES, availability/accessibility of health care, diagnostic practices, and hospital utilization. Patterns in geographic variation were assessed based on physiographic characteristics and proximity to the Atlantic coastline. Significant variation was identified with an increase in sarcoidosis rates proximal to the Atlantic coastline. Population characteristics were identified that appeared to explain regional variation in sarcoidosis in Caucasians; however, regression analysis was unable to explain the regional differences in disease distribution by variation in SES, diagnostic practices, accessibility/availability, or hospital utilization in African Americans. These results suggest that the development of sarcoidosis is associated with a geographically linked risk factor in African Americans. This work supports the need for additional studies that will identify this risk factor(s).

In writings on the theory of valuing, many take the position that impacts on the relevant outcome dimensions should be aggregated to arrive at one summary assessment of program merit. A contrary position is taken here, specifying that the impacts should be kept separate and unweighted and expressed only in their own original measurement scales. All impacts, however, should be portrayed, including those for which no rigorous data analysis has been carried out. It is argued that aggregating, even by the individual stakeholder, is both futile and misleading. An extensive evaluation of the effects of research grants on the university is included as a full-scale illustration of the method. Financial impacts are considered, as well as impacts on faculty and student quality, on university prestige, and on the quality of instruction.

Gene therapy approaches for the treatment of malignant tumors will require high-level expression of therapeutic genes in tumors compared with normal tissues. This may be achieved either by targeted gene delivery to tumor cells or by the use of tumor-specific promoters. Here, we describe the use of a novel conjugate consisting of a tumor-reactive monoclonal antibody (mAb), designated AF-20, coupled to a DNA-binding cationic amphiphile, cholesteryl-spermine, for gene delivery to hepatocellular carcinoma (HCC) cells. The high-affinity mAb, AF-20, recognizes a rapidly internalized 180-kd cell-surface glycoprotein that is abundantly expressed on HCC and other human tumors. The AF-20 mAb and an isotype-matched control antibody (C7-57) were covalently coupled to cholesteryl-spermine. Binding and internalization of AF-20-cholesteryl-spermine was confirmed by fluorescence microscopy using fluorescein isothiocyanate (FITC)-labeled anti-mouse IgG antibody. Following transfection of FITC-labeled oligonucleotides and ethidium monoazide-labeled plasmid DNA, cellular uptake and intracellular localization of nucleic acids were examined by laser scanning confocal microscopy. Transfection of luciferase or beta-galactosidase reporter genes complexed to AF-20-cholesteryl-spermine resulted in high levels of gene expression in AF-20 antigen-positive tumor cells. Very low levels of gene expression were observed using the control compound (C7-57-cholesteryl-spermine), which does not recognize the AF-20 tumor antigen or when AF-20 antigen-negative NIH 3T3 cells were transfected with AF-20-cholesteryl-spermine. Thus, covalent coupling of the AF-20 mAb to cholesteryl-spermine generated a highly specific and efficient nonviral vector system for targeted gene delivery to AF-20 antigen-positive HCC cells.

Background & Aims: Long-term ethanol consumption is known to impair the ability of the liver to regenerate, but the molecular mechanisms are poorly understood. Multiple growth factors promote hepatocyte proliferation, some of which involve the insulin receptor substrate 1 (IRS-1)-mediated signal transduction pathway. To explore effects of ethanol on the IRS-1 signal liver growth in vivo, studies in transgenic mice overexpressing IRS-1 in the liver were performed because these mice show constitutive activation of the downstream signal transduction pathways leading to enhanced hepatocyte proliferation., Methods: Tyrosyl phosphorylation of IRS-1 and subsequent protein-protein interactions were examined in liver lysates from animals fed ethanol or control diet. Activity of phosphatidylinositol-3 kinase (PI3K) and mitogen-activated protein kinase (MAPK) was assessed by specific enzymatic assays. Hepatocyte proliferation was measured by incorporation of [3H]thymidine into liver DNA., Results: Tyrosyl phosphorylation of IRS-1, association of IRS-1 with PI3K, and activation of downstream PI3K and MAPK pathways were greatly reduced as a result of long-term ethanol consumption. Ethanol virtually abolished the enhanced hepatocyte DNA synthesis induced by expression of the IRS-1 transgene., Conclusions: Altered transmission of growth signals through the IRS-1-mediated signal transduction cascade may represent a molecular mechanism of how ethanol inhibits hepatocyte proliferation.

Chronic ethanol toxicity impairs liver regeneration, inhibits DNA synthesis, and mutes cellular responses to growth factor stimulation. Previous studies demonstrated that the adverse effects of ethanol are mediated by inhibition of tyrosyl phosphorylation of the insulin receptor and the insulin receptor substrate-type 1 (IRS-1). However, overexpression of IRS-1 leads to increased DNA synthesis and cellular transformation due to constitutive activation of mitogen-activated protein (MAP) kinase. The present study examines the effects of ethanol on insulin signaling through IRS-1 in FOCUS hepatocellular carcinoma cells, which overexpress IRS-1, to determine whether such cells were resistant to the inhibitory effects of ethanol. The results demonstrated that ethanol treatment (100 mM) caused 30 to 50% reductions in the levels of insulin-stimulated tyrosyl phosphorylation of the insulin receptor beta-subunit, tyrosyl phosphorylation of IRS-1, phosphorylation of Erk2, association of phosphatidylinositol-3 kinase with tyrosyl-phosphorylated IRS-1, and MAP kinase and phosphatidylinositol-3 kinase activities. In contrast, ethanol treatment had no effect on epidermal growth factor-stimulated tyrosyl phosphorylation of Shc. Corresponding with the pronounced inhibition of MAP kinase, ethanol treatment resulted in 30 to 50% reductions in the expression levels of two important insulin-responsive genes: glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and proliferating cell nuclear antigen (PCNA). The findings suggest that, in FOCUS hepatocellular carcinoma cells, which overexpress IRS-1, ethanol treatment substantially inhibits IRS-1 and MAP kinase signaling and growth-associated gene expression, but has no effect on Shc phosphorylation, which activates p21ras through an IRS-1 independent pathway.

Background: Flight crews are exposed to elevated levels of cosmic radiation and to magnetic fields generated by the aircraft's electrical system. The purpose of this study was to quantify these two occupational exposures., Methods: Magnetic fields were measured during 37 flights (23 in the cockpit and 14 in the cabin) using an Emdex Lite personal dosimeter. All cockpit measurements were taken on the B737/200. Cabin measurements were taken in several aircraft types, including the B737, B757, DC9, and L1011. Cosmic radiation was computer estimated for 206 flights using the Federal Aviation Administration's program CARI-3C., Results: Magnetic field levels in the cockpit had a mean value of approximately 17 milliGauss (mG), while cabin measurements were lower (mean values of approximately 3 or less in economy, 6 in first class, 8 in front serving areas). Cosmic radiation equivalent dose rates to bone marrow and skeletal tissue ranged from 0.3 to 5.7 microsieverts per hour., Conclusions: Elevated magnetic field levels in front serving areas and the cockpit suggest the need for further study to evaluate long-term exposure to flight crew members who work in these areas. Cosmic radiation levels are well below occupational limits for adults, but may require some pregnant flight crew members to adjust their flying time or routes.

The airline industry may be an occupational setting with specific health risks. Two environmental agents to which flight crews are known to be exposed are cosmic radiation and magnetic fields generated by the aircraft's electrical system. Other factors to be considered are circadian disruption and conditions specific to air travel, such as noise, vibration, mild hypoxia, reduced atmospheric pressure, low humidity, and air quality. This study investigated mortality among US commercial pilots and navigators, using proportional mortality ratios for cancer and noncancer end points. Proportional cancer mortality ratios and mortality odds ratios were also calculated for comparison to the proportional mortality ratios for cancer causes of death. Results indicated that US pilots and navigators have experienced significantly increased mortality due to cancer of the kidney and renal pelvis, motor neuron disease, and external causes. In addition, increased mortality due to prostate cancer, brain cancer, colon cancer, and cancer of the lip, buccal cavity, and pharynx was suggested. Mortality was significantly decreased for 11 causes. To determine if these health outcomes are related to occupational exposures, it will be necessary to quantify each exposure separately, to study the potential synergy of effects, and to couple this information with disease data on an individual basis.

Background/aims: Viral serum concentrations are considered to have a clinical, prognostic and epidemiological impact on patients with hepatitis C infection. The purpose of this study was to test whether quantitation of HCV-RNA is possible by PCR in combination with DNA-ELISA., Methodology: PCR with 25 to 35 cycles was performed with variable concentrations of cloned HCV-cDNA or the serum of patients with chronic hepatitis C. The amplified PCR-products were detected by agarose gel or by DNA-ELISA., Results: The detection limit of PCR with DNA-ELISA or gel detection decreased with increasing numbers of PCR cycles. However, the correlation of the optical density of the DNA-ELISA with the HCV-cDNA concentration decreased with increasing numbers of PCR as well (r=0.8 vs. r=0.29; 25 vs. 35 PCR-cycles). HCV-RNA was found in the sera of 19 of 30 patients (63%) with chronic hepatitis C by gel detection and in 14 of 30 patients (47%) by DNA-ELISA subsequent to PCR with 35 cycles., Conclusions: The PCR/DNA-ELISA technique allows a semiquantitative determination of HCV-cDNA concentrations down to 103 genomes/ul. However, to obtain a reasonable sensitivity for HCV concentrations in the serum of patients with hepatitis C, the number of PCR cycles has to be increased to numbers too high to provide reliable quantification. Further studies should be done to evaluate whether the detection systems can be improved to obtain a sufficient sensitivity for quantitative HCV-PCR. A prerequisite for the use of PCR in combination with quantifiable detection systems is that a PCR-cycle number is chosen that keeps amplification within the logarithmic phase.

The present study prospectively evaluated the value of liver biopsy in patients with chronic hepatitis B (N=75) and C (N=135) prior to interferon therapy. Biopsy specimens revealed cirrhosis in 26% of patients with hepatitis B and 30% with hepatitis C. Although cirrhosis was not predictable by laboratory values in individual patients mean gamma-GT, alkaline phosphatase, and bilirubin levels were significantly higher in patients with cirrhosis compared to those without. Since cirrhosis significantly impairs the response rate to interferon therapy in hepatitis C but not in hepatitis B, liver biopsy is important for the management of chronic hepatitis C infection. In 88% of patients with serum HBV-DNA, irrespective of the serum HBeAg status, chronic active hepatitis was seen. Similarly, chronic active hepatitis was found in 84% of patients with elevated aminotransferases and hepatitis C antibodies. Thus, chronic active hepatitis was diagnosed in the majority of cases with chronic viral hepatitis, showing that this histopathological diagnosis is of little additional value for the recommendation on interferon treatment in these patients. However, none of the other grading systems of liver biopsy specimens described so far have been evaluated for their ability to predict overall prognosis or response rates to interferon therapy. Therefore, the physician is presently left with the questionable value of a procedure with well-known risks and costs in patients suitable for interferon treatment. Hence, prospective randomized controlled studies to evaluate histopathological grading systems are urgently needed to redefine the necessity of liver biopsy in this routine clinical setting.

The occupational and environmental medicine (OEM) gap in US medical education is widely recognized. In 1992, a federal initiative stimulated a primary care approach to improve residency training in South Carolina. This three-part report documents progress in designing and implementing an OEM curriculum, which is family medicine-centered. Each of the state's residency training programs participate in an ongoing Environmental Medicine Curriculum Committee effort. Part 1, discusses the needs assessment; Part 2, the five key elements of curriculum; and Part 3 details a clinical guide to the OEM patient.

Part II of our three-part report examines five of the key elements for occupational and environmental medicine (OEM) training in family medicine residency. These were introduced by the Environmental Medicine Curriculum Committee (EMCC) faculty in South Carolina under a Department of Energy (DOE) grant to the Environmental Hazards Assessment Program (EHAP) of the Medical University of South Carolina, 1992-1997. Each element is being designed, tested, and updated by clinicians in the residency network. A pilot study of 100 third-year medical students conducted in 1996 suggests the difficulty in implementing OEM skills in current family medicine training.

A four-prototype approach to the occupational and environmental medicine (OEM) patient in a busy primary care setting is described. A 2 x 2 table illustrates the two diagnostic, interrelated tasks during the outpatient, non-urgent visit: (a) sick? yes/no, and (b) exposed? yes/no. One may have the basic skills for task (a) but feel insecure for task (b). With OEM experience, creative use of resources (databases and consultants), and patient cooperation, a better balance between task (a) and task (b) can be achieved. The Environmental Medicine Curriculum Committee (EMCC) initiative described in Part I and Part II of this study has developed this patient-centered model to help the resident in training cope as he or she tries to deal with emerging patient concerns from the workplace and beyond. In November 1996, an expert panel of consultants representing OEM, public health, and family medicine endorsed the prototype OEM patient model for further development.

Persistent hepatitis B virus (HBV) infection often leads to the development of chronic hepatitis, cirrhosis and hepatocellular carcinoma. There is a need to develop new antiviral approaches for the treatment of this disease. We have explored various nucleic acid-based strategies designed to inhibit HBV replication including: the use of antisense RNA and DNA constructs, DNA-based immunization techniques to stimulate broad-based cellular immune responses with particular emphasis on the generation of cytotoxic lymphocyte (CTL) activity to viral structural proteins, hammerhead ribozymes to cleave HBV pregenomic RNA in vitro and dominant negative HBV core mutant proteins as inhibitors of nucleocapsid formation within cells. In order to optimize these antiviral effects, various novel expression vectors have been developed to deliver such DNA constructs to cells. For example, adenoviral vectors carrying genes that encode for dominant negative proteins have been employed to transfect hepatocytes in vitro and in vivo. In addition, plasmid vectors have been produced to promote expression of HBV structural genes following injection into muscle cells as a means to stimulate the host's cellular and humoral immune response in the context of histocompatibility antigen (HLA) class I and II antigen presentation. These experimental approaches may have important implications for the generation of efficient antiviral effects during chronic HBV infection.

The human insulin receptor substrate-1 (hIRS-1) is a key intracellular protein involved in various cytokine signaling pathways associated with cell growth. We have previously demonstrated that stable transfection and overexpression of hIRS-1 in human hepatoblastoma cells in vitro leads to the constitutive activation of the mitogen-activated protein kinase (MAPK) cascade. In this setting, hIRS-1 acts as a dominant oncogene and will induce neoplastic transformation of NIH 3T3 cells. In the present study, the biologic effects of hIRS-1 overexpression in the liver was analyzed using both clinical tumor samples and a newly developed transgenic mouse model. We have found that approximately 40% of 22 human hepatocellular carcinoma (HCC) tumors had enhanced (>200%) hIRS-1 gene expression compared with adjacent non-involved liver tissue. There was a significant relationship between the level of hIRS-1 overexpression and the tumor size; this finding suggests a possible role for hIRS-1 in tumor progression. To determine if downstream signal transduction cascades were activated by overexpression of hIRS-1 in hepatocytes, we established a transgenic mouse model using an hIRS-1 construct driven by an albumin promoter/enhancer element to direct liver specific expression. The overexpressed hIRS-1 protein was found to be tyrosyl phosphorylated and interacted with downstream SH2-containing molecules such as the p85 subunit of phosphatidylinositol-3 kinase (PI3K), Grb2 adaptor, and SHP2 phosphatase proteins. The functional consequences of hIRS-1 overexpression were reflected by constitutive activation of both the MAPK and PI3K signal transduction cascades. More important, overexpression of hIRS-1 in the transgenic liver led to increased hepatocyte DNA synthesis. Our findings indicate that hIRS-1 overexpression induces downstream signaling molecules associated with hepatocyte growth and may potentially enhance tumor progression of HCC.

A library of monoclonal antibodies (MoAbs) has been produced against a human hepatocellular carcinoma (HCC) cell line designated FOCUS in order to study the antigenic properties of transformed hepatocytes. Several monoclonal antibodies (MoAbs) were initially selected for study since they bound to antigens which were overexpressed in HCC tissues compared with the adjacent uninvolved normal liver counterpart; in addition, these MoAbs revealed low level antigen expression on other normal human tissues. Subsequently, HCC cell lines were metabolically labelled and the antigens further characterized by immunoprecipitation and Western blot analysis. If the MoAb recognized a primary linear epitope on a protein, cloning was performed using a lambda GT11 cDNA expression library prepared from the FOCUS HCC cell line. These studies characterized the HCC associated antigen(s) at the molecular level. This review illustrates the value of such an experimental approach to search for and identify HCC associated antigens and emphasizes the biological properties of novel proteins may be defined and characterized by these techniques. More important, our investigations have described unique proteins that may not only be important in the pathogenesis of HCC but also demonstrates how such antigen-antibody systems may be used to develop strategies for immunotargetting and gene therapy of HCC.

Recent advances in our understanding of viral hepatitis involve the discovery and further characterization of the hepatitis C virus and the interferon treatment of patients with chronic viral hepatitis. Liver cirrhosis and primary hepatocellular carcinoma can develop after some years of disease. Interferon is the only effective treatment, which may improve symptoms and prognosis in some patients. Long-term responses with termination of viral replication are seen in 40% of patients with hepatitis B and 15-25% of patients with hepatitis C. In some patients complete elimination of the virus occurs. Higher response rates are achievable in subgroups of patients with favourable prognostic constellations. Patients have to be informed about side-effects and risks of interferon therapy. Treatment in uncomplicated cases is performed on an outpatient basis. The present paper reviews diagnosis, indications, contraindications and practical considerations concerning interferon treatment in patients with chronic viral hepatitis.

Thorough differential diagnosis in patients with autoimmune hepatitis is important since other liver disorders need different treatment regimen. Elevated transaminases and gamma-globulines and autoantibodies should make one think of autoimmune hepatitis. Liver biopsy is helpful but usually not a definitive proof of the diagnosis. Immunosuppressive therapy has to be administered for years and possibly leads to serious side effects. Therapy should only be discontinued if a complete remission is induced. Relapses after cessation of medical treatment occur frequently. If no remission is achieved lifelong immunosuppressive therapy has to be given. In decompensated disease liver transplantation offers a treatment with good prognosis.

Fourteen patients who developed acute post-transfusion hepatitis C after open-heart surgery were studied for seroconversion, viremia, and aminotransferase. Anti-HCV antibodies were measured by first and second generation ELISA and became positive between one week and more than 6 months after infection. Seroconversion in four patients and passively transfused antibodies were only found by the second generation assay, indicating its significantly higher sensitivity. Viremia was detected by reverse transcription and the polymerase chain reaction within the first 4 weeks of infection in 13 patients and persisted for more than 2 years in all of them. One patient died of cardiac cause. Viral strains were heterogeneous between the different patients, but showed no significant variation within one patient during the course of hepatitis deduced from the results with different sets of oligonucleotides. Viremia preceded hepatitis by 4 weeks, seroconversion determined by ELISA II followed after an 8 week interval, and anti-C-100 antibodies appeared 26 weeks later. Aminotransferase activities returned to normal values in 10 patients.

Studies on the cryopreservation of 162 four-cell and eight-cell human embryos indicate that morphological survival and pregnancies can be achieved by specific techniques of freezing and thawing. Survival rates are highest when embryos are cooled at 0.3 degrees C/min to -80 degrees C in the presence of 1.5 M dimethylsulfoxide (DMSO) and thawed at +8 degrees C/min from -80 to +4 degrees C. Morphological survival of four-cell and eight-cell human embryos after freezing and thawing is not affected by irregularites in blastomere size or the presence of small cytoplasmic fragments. Light and electron microscopic examination of fixed specimens indicates a good correlation between the appearance of frozen-thawed embryos at the dissecting microscope level and the extent of cryoinjury. Sixty-eight of 136 four-cell and eight-cell embryos (50%) survived with half or more of their blastomeres intact when cooled to low temperatures and thawed at the rates described. The transfer of these 68 embryos into 45 patients resulted in nine pregnancies.

Two patients with spontaneous aortocaval fistulas are described and compared with 67 cases reported in the English literature. Symptoms may vary widely; however, the presence of an expansile abdominal mass with a continuous bruit is usually diagnostic. The only successful management is promt repair of the vena caval defect and the aortic aneurysm. A third patient with spontaneous rupture of an abdominal aortic aneurysm into the left renal vein is alos described. Only five similar cases could be found in the work literature. Left flank pain, pulsatile abdominal mass, continuous bruit, and hematuria is the usual clinical picture. All of these cases involved an anomalous left retroaortic renal vein and all patients survived the necessary surgical correction. The operation of choice is closure of the defect in the retroaortic left renal vein and repair of the aneurysm.

One hundred nine percutaneous catheterizations of synthetic vascular grafts in 89 patients who had angiographic procedures were reviewed to determine the risk of major complications. Ninety-six of the catheterizations were inserted into the inguinal portion of aortofemoral grafts. There were no instances of hematoma, graft infection, aneurysm formation, suture line disruption, or embolic events distal to the puncture site. One local thrombus developed within a vascular graft that was corrected by a simple thrombectomy performed with a surgical catheter. One puncture site required 2 hours of compression to maintain hemostasis. Because of the extremely low risk of complications from catheterization of synthetic vascular grafts, it is the preferred route for angiographic procedures when the native femoral arterial route is unavailable.

A normal baby girl was delivered after the successful transfer of two thawed embryos which had been frozen for eight weeks. Embryo cryopreservation may improve the chances of conception by women who are undergoing in-vitro fertilization (IVF), reduce the risks of multiple pregnancies in association with IVF, and offer the chance of conception to women with serious gynaecological disease which threatens ovarian function.

Studies on the cryopreservation of ninety-seven 4-cell and 8-cell human embryos indicate that morphologic survival can be achieved by means of two different cryoprotectants and two different freezing procedures. To date, pregnancies can be achieved after freezing and thawing of 8-cell human embryos cooled at 0.3 degree C per minute to -80 degrees C in the presence of 1.5 molar dimethyl sulfoxide (DMSO) and thawed at +8 degrees C per minute from -80 degrees C to +4 degrees C. By this procedure, 27 of 47 (57%) embryos frozen survived with 50% or more of their blastomeres intact. The transfer of these 27 embryos to 22 patients resulted in five pregnancies (22%). Morphologic survival of 4-cell and 8-cell human embryos after freezing and thawing is not affected by slight irregularities in blastomere size or the presence of small cytoplasmic fragments. Light and electron microscopic examination of fixed specimens indicates a good correlation between the appearance of frozen-thawed embryos at the dissecting microscope level and the extent of cryoinjury.

Oocytes were obtained from patients with tubal infertility at fixed times after the onset of the endogenous LH rise or hCG injection, and were inseminated immediately after recovery or after periods of 4-4 1/2, 5-5 1/2 and 6-6 1/2 h in culture in vitro. Delayed insemination resulted in a marked increase in the proportion of oocytes that were fertilized and developed to normal embryos and maximum rates occurred after 5-5 1/2 h in culture (0-1/2 h, 26%; 4-4 1/2 h, 50%; 5-5 1/2 h, 89%; 6-6 1/2 h, 69%). The range and mean (+/- s.d.) intervals from insemination for the pronuclear and early cleavage stages were 27-43 (35.6 +/- 4.4) h for 2-cell stages, 36-65 (45.7 +/- 8.3) h for 4-cell stages, 45-73 (54.3 +/- 12.6) h for 8-cell stages and 68-85 h for the 16-cell stage. In 7/50 patients receiving 1 or 2 embryos at the 2-, 4- and 8-cell stages, fetal development was normal and 2 women had twin pregnancies (36% success compared with 8% for single embryos). All pregnancies were from the groups in which insemination was delayed for 5-6 1/2 h. It is concluded that a short period of culture in vitro may allow the completion of oocyte maturation, and improve the results of in-vitro fertilization.

The internal carotid back pressure and arterial blood gas measurements have been employed in 269 patients undergoing 332 carotid endarterectomies in an effort to identify individuals at high risk of stroke during surgery. Patients having an internal carotid back pressure less than 25 Torr were operated using an inlying shunt. There were 159 patients having a PaCO2 greater than 45 Torr, 95 individuals with a PaCO2 between 35 to 45 Torr and 78 cases with a PaCO2 less than 35 Torr. The mean internal carotid back pressure was 63 Torr in the hypocarbic group and 45 Torr in the hypercarbic patients which represents a highly significant inverse relationship between PaCO2 and carotid back pressure (P less than 0.0002). There were four neurological deficits following surgery in the hypercarbic group and one each in the normocarbic and hypocarbic groups. These findings suggest a lower stroke incidence in patients having hypocarbic or normocarbic general anesthesia than those receiving hypercarbic general anesthesia. The low overall stroke rate of 2% indicates the safety of selective shunting during carotid endarterectomy.

The classical subclavian steal syndrome is a larcenous vertebrobasilar insufficiency, secondary to retrograde flow in the vertebral artery. The authors present their experience with an unusual variant of subclavian steal in which the ipsilateral vertebral artery was completely or partially occluded, or arose from the aortic arch. These patients had symptoms typical of vertebrobasilar insufficiency--dizziness or brain stem transient ischemic attacks--despite steal through relatively small cervical collaterals to the obstructed subclavian artery. Physical findings of diminished pulses and blood pressure in the involved upper extremity are similar to those in the common form of subclavian steal. The alternate collaterals found in these patients are documented by angiography and other potential collaterals are reviewed. All three symptomatic patients were treated successfully by carotid-subclavian bypass or anastomosis of the subclavian to the common carotid artery. They have remained asymptomatic for 1 1/2 to 3 years following operation. The potential for development of subclavian steal in the absence of a vertebral artery to provide collateral flow adds another reason for abandoning vertebral artery ligation as an alternative treatment for the subclavian steal syndrome.

Preimplantation mouse embryos that were exposed to fluorescein diacetate (FDA) accumulated intracellular fluorescein and fluoresced brightly under ultraviolet (u.v.) light. The rate at which intracellular fluorescein was lost from the cells was measured at 37, 28 and 4 degrees C and the rate decreased as the storage temperature decreased. The rate at which intracellular fluorescein accumulated increased as FDA concentration increased until a maximum rate was attained. The ability to accumulate intracellular fluorescein could be removed by heating embryos at 56 degrees C for 30 min or by damaging the cell membrane. Cells grown under inadequate culture conditions lost the ability to accumulate intracellular fluorescein. Exposure of 2-cell mouse embryos to FDA and u.v. light did not alter the rate of blastocyst formation in vitro, and exposure of blastocysts to FDA and u.v. light did not alter the rate of implantation or post-implantation development in vivo.

Transconjunctival oxygen tension (PcjO2) was studied using a hypobaric chamber and during mountaineering excursions. Measurements obtained during acute chamber exposures (15-20 min) at sea level, 1829 m (6,000 ft), 3048 m (10,000 ft), 4267 m (14,000 ft) and return to sea level were (means +/- SEM): 60.1 +/- 2.7, 49.1 +/- 1.8, 38.3 +/- 2.4, 27.4 +/- 1.5, and 61.1 +/- 2.8 mm Hg, respectively (n = 13). The ratio of PcjO2 to arterial blood oxygen tension (PaO2) did not change in a consistent manner between sea level and 4267 m; PcjO2 was 74 +/- 6.9% of PaO2. The 16 subjects participating in the mountaineering phase of the study revealed similar means at sea level and 1829 m (57.4 +/- 2.4 and 46.3 +/- 1.9 mm Hg respectively), but a smaller decrement was observed at 3048 m (43.0 +/- 1.6 mm Hg). The difference between mountain and chamber values may be accounted for by a partial acclimatization to altitude brought about by longer exposure on the mountain excursions. A comparison between PcjO2 and transcutaneous oxygen tension during the chamber study suggests that a greater precision and sensitivity is obtained with measurement of oxygen tension at the conjunctival site. PcjO2 measurement is a non-invasive reflection of PaO2 which is suitable for continuous monitoring during hypoxia studies.

True aneurysms have developed in nonreinforced, expanded polytetrafluoroethylene (PTFE). We report our experience in arterial reconstructions with PTFE in the legs of patients having symptomatic occlusive disease. Fifty-four femoropopliteal or femorotibial bypass operations were performed in 51 patients between January 1975 and December 1976. An unsuitable saphenous vein for a vascular conduit was found in 14 patients, and reconstruction was done with PTFE (IMPRA-graft). Two of the 14 PTFE grafts were composite and used a segment of saphenous vein. Aneurysmal dilation developed in five PTFE grafts (36%) in four patients three to 36 months following placement. Nonreinforced PTFE conduits as manufactured during 1975 and 1976 are unsatisfactory for use as limb arterial bypass grafts because of the high incidence of aneurysmal change. Those that are implanted must be followed up indefinitely because of late aneurysmal formation and rupture. Newer PTFE graft modifications should be used with caution.

The widespread use of clomiphene citrate and exogenous gonadotrophins for in vitro fertilization (IVF) in human frequently results in the production of multiple embryos. Replacement of more than two embryos increases pregnancy rate but may result in multiple pregnancies with increased pre- and post-natal abnormality. Preservation of embryos for a limited time allows fewer embryos to be replaced on several different occasions and thus the problems of multiple pregnancy can be minimized, the effectiveness of a single IVF procedure increased and embryo replacement in adverse maternal conditions avoided. Preimplantation embryos have been successfully cryopreserved in many animal species. The sensitivity of embryos to cooling and freezing varies between species and stages of embryo development. We report here the cryopreservation procedures that allow a high survival rate of four- and eight-cell human embryos and the establishment of a pregnancy following the freezing and storage of an eight-cell embryo for 4 months in liquid nitrogen. The pregnancy terminated at 24 weeks' gestation due to development of a septic Streptomyces agalactiae chorion amnionitis after premature membrane rupture.

The following study was undertaken to study the effects of multiple stressors on the pituitary-testicular axis in men. We examined the endocrine responses of 16 healthy young men participating in a mountain training exercise. Blood was drawn at 1830 m just before ascent (t = 0 h), after an overnight rest at 3050 m (t = 24 h), and immediately after a descent from 3050 m in adverse conditions (t = 48 h). Plasma E2 increased significantly through the study periods (medians: 74, 104, 164 pmol/l at t = 0, 24, 48 h) while 17 alpha-hydroxyprogesterone progressively decreased. Testosterone and the bioactive LH to immunoreactive LH ratio decreased only at 48 h. There were no changes observed for plasma cortisol, prolactin or thyroxine. The observed rise in E2 may be due to one or more stressors associated with altitude, including hypoxia and increased solar radiation. This data suggests a role for E2 in the secondary testosterone decrease.