Conscious recovery response in post-hepatic transplant as a function of time-related acute hepatic encephalopathy.

BACKGROUND: H Coma due to acute hepatic failure produces a high mortality rate with rapid progression of cerebral edema and brain herniation. Early transplantation increases survival of patients with acute hepatic encephalopathy. In previous studies, scant attention has focused on the conscious recovery time after living donor liver transplantation (ldlt) and whether the conscious recovery time was directly proportional to the length of coma before transplantation. PATIENTS AND METHODS: We have reported herein three adult patients with decompensated chronic end-stage liver disease who underwent right lobe LDLT. Their general conditions had markedly deteriorated; two patients displayed massive ascites. All three subjects displayed grade IV encephalopathy with endotracheal intubation and intensive care management. Their biochemical data revealed hyperammonemia, marked cholestasis, and coagulopathy. RESULTS: After LDLT the patients recovered from coma at a mean time similar to that in coma. Preoperatively the patients exhibited acute deep coma with respiratory failure on preoperative days 5, 3, and 1 with consciousness regained on postoperative day 5, 3 and 1, respectively. CONCLUSION: We suggest that patients with acute deep coma (grade IV), who were formerly regarded as irreversible, benefit with LDLT, preventing worsening of complications, and that shows a time-dependent recovery the pretransplant comatose status.

Assembly of hepatitis delta virus-like empty particles in yeast.

Large delta antigen (L-HDAg) of hepatitis delta virus (HDV) and small-form hepatitis B surface antigen (HBsAg) of helper hepatitis B virus have previously been shown to be the minimum components for the assembly of HDV-like particles in mammalian cells. Extending from this finding, we coexpressed L-HDAg and small HBsAg in Saccharomyces cerevisiae to study their assembly in yeast cells. The assembly of virus particles from L-HDAg and HBsAg in yeast was demonstrated by their coexistence in the same isopycnic fractions and by the coimmunoprecipitation of L-HDAg with HBsAg using an antibody against HBsAg (anti-HBs). Furthermore, after purification by affinity chromatography with anti-HBs, HDV-like particles with size and morphology similar to those derived from mammalian cells could be visualized by electron microscopy. Mice immunized with yeast-derived HDV-like particles simultaneously acquired antibodies against HBsAg and HDAg, indicating that both viral proteins are antigenic. The results indicated that S. cerevisiae could serve as a host for the assembly of HDV-like empty particles. This system may be useful in investigating cellular processes involved in HDV assembly and in producing ample amount of HDV-like particles for structural and immunological studies.

A minimal regulatory region maintains constitutive expression of the max gene.

Max is a basic helix-loop-helix/leucine zipper protein that forms heterodimers with the Myc family of proteins to promote cell growth and with the Mad/Mxi1 family of proteins to inhibit cell growth. The role of Max as the obligate binding partner for these two protein families necessitates the observed constitutive expression and relatively long half-life of the max mRNA under a variety of growth conditions. In this study, we have used the chicken max gene to map DNA elements maintaining max gene expression in vertebrate cells. We have identified a minimal regulatory region (MRR) that resides within 115 bp of the max translation initiation site and that possesses an overall structure typical of TATA-less promoters. Within the MRR are two consensus binding sites for Sp1, a ubiquitously expressed transcription factor that plays a role in the expression of many constitutive genes. Interestingly, we show that direct binding by Sp1 to these sites is not required for MRR-mediated transcription. Instead, the integrity of a 20-bp DNA element in the MRR is required for transcriptional activity, as is the interaction of this DNA element with a 90-kDa cellular protein. Our data suggest that it is the persistence of this 90-kDa protein in vertebrate cells which drives max gene expression, insulates the max promoter from the dramatic changes in transcription that accompany cell growth and development, and ensures that adequate levels of Max will be available to facilitate the function of the Myc, Mad, and Mxi1 families of proteins.

Stimulatory effects of immunoreactive growth hormone on proliferation of a human lymphocyte cell line.

Previous studies have indicated the secretion of a growth hormone-like molecule by the lymphocyte T-cell line, H9. We examined the autocrine growth-promoting effects of this T-cell derived factor. H9 conditioned medium stimulates proliferation of H9 cells themselves in a dose-dependent fashion. This growth stimulating effect could be blocked by anti-human growth hormone antiserum, but could not be simulated by addition of growth hormone only or interleukin 2 only, or a combination of both. Dexamethasone inhibited H9 growth in low nutrient culture conditions and seemed to somewhat offset the growth promoting effect of the hGH-like molecule. However, the exact role played by dexamethasone in H9 cell growth and death, as well as the exact mechanism by which the hGH-like molecule exerted its growth-promoting action, remain to be elucidated.

Structural analysis of the chicken max gene.

The recent identification of Max, a nuclear phosphoprotein that dimerizes with members of the Myc protein family, has provided an additional tool to examine the role of the Myc oncoprotein as a sequence-specific DNA binding protein and a potential regulator of gene transcription. Here we report the nucleotide sequence of an avian max gene isolated from a lambda EMBL3 genomic library prepared from size-selected chicken embryo fibroblast DNA. The complete transcription unit encoding chicken Max is contained on a 5.7 kbp BglII DNA fragment which expresses an appropriately sized max mRNA of 1.5 kb following transfection of C3H10T1/2 mouse fibroblasts. The coding region of the chicken max gene is organized into five exons and the overall identity between the human and chicken max coding sequences is 85% at the nucleotide level and 96% at the amino acid level. The basic helix-loop-helix/leucine zipper region, the casein kinase II phosphorylation sites and the nuclear localization signal sequence are 100% conserved in all vertebrate Max proteins characterized to date. DNA sequence analysis of the 5' flanking region of the chicken max coding sequence reveals the absence of consensus TATA or CAAT motifs, but the presence of numerous GC-rich sequences that are typical in eukaryotic genes which are expressed constitutively in different tissues and under different growth conditions.

Inhibitory effects of ascorbic acid on growth of leukemic and lymphoma cell lines.

Vitamin C has been suggested and disputed as an anti-cancer agent. Previous in vitro studies using either primary cell cultures from cancer patients or tumor cell lines have suggested that tumor cells with different lineages may have different sensitivities to ascorbic acid. In this study we report characterization of the effects of ascorbic acid on growth of two ascorbic acid sensitive and one ascorbic acid resistant lymphocyte tumor cell lines. The cytotoxic effects of ascorbic acid on the sensitive cell lines were time and dosage dependent. Furthermore, the energy state of the ascorbic acid sensitive cells was affected by the presence of ascorbic acid before the cells became apparently non-viable, as demonstrated by 31P nuclear magnetic resonance spectroscopy. The existence of these lymphocyte cell lines with varying sensitivities to ascorbic acid may provide a useful model system for further understanding of vitamin C action on cancer cells.

Immunoreactive growth hormone production by human lymphocyte cell lines.

1. Two human lymphocyte cell lines, a T-cell line and a B-cell line, were shown to produce and secrete immunoreactive growth hormone (irGH). The irGH molecules secreted by the two cell lines appeared to be de novo synthesized and their molecular size was similar to that of pituitary GH as well as irGH secreted by peripheral blood lymphocytes. 2. Affinity-purified irGH molecules had human growth hormone (hGH)-like mitogenic activity on Nb2 cells. These findings indicate that the irGH molecules produced by H9 and IM9 were similar to hGH in structure. 3. However, the irGH messages could not be amplified by polymerase chain reaction (PCR) primers which had been demonstrated to be able to amplify reverse-transcribed hGH messenger RNA successfully, suggesting that the lymphocyte-derived irGH and pituitary hGH are not exactly identical molecules. 4. We conclude that the H9 and IM9 cells produce a growth hormone-related molecule whose structure is different from that in the anterior pituitary.

Inhibition of immunoreactive growth hormone secretion from lymphoid cell lines by dexamethasone.

The regulation of irGH secretion by the immune system was examined using lymphoid cell lines, H9 and IM9. Using a highly sensitive immunoassay, irGH secretion by H9 was negatively regulated by dexamethasone, whereas many other regulators of hGH secretion, including hormones, monoamines, and second messenger, had no measurable effect on irGH secretion. Treatment of H9 cells with dexamethasone for 48 hours could cause as high as 70% reduction in irGH secretion without affecting either cell numbers or viability. Using IM9, neither growth hormone releasing hormone nor thyrotropin releasing hormone had significant effect on either irGH steady-state level transcripts or irGH secretion. These findings suggest that irGH secretion by lymphocytes was regulated in a different manner from that by pituitary cells.