Acute exacerbation in hepatitis B e antigen positive chronic type B hepatitis. A clinicopathological study

During a 6-year (mean 24.5 months) follow-up study of 237 HBeAg-positive patients with biopsy-verified chronic type B hepatitis, 199 episodes of acute exacerbation (SGPT greater than 300 IU/l) were observed in 148 patients. The clinical and laboratory findings of these acute exacerbations were less severe than classic acute viral hepatitis (P less than 0.001) but with remarkable overlapping. The main histological changes of acute exacerbations were those of lobular hepatitis, even with bridging hepatic necrosis which predicted subsequent HBeAg clearance. Anti-HBc IgM was positive in 14.4% of the exacerbations. All of these findings made acute exacerbation of chronic type B hepatitis indistinguishable from acute viral hepatitis aside from chronic clinical history. Hepatitis A virus, delta agent and possibly non-A, non-B virus(es) were responsible for some of the episodes of clinical exacerbations.

Metabolites of Bacillus sp. isolated from flax-suppressive soil

A culture of Bacillus sp. was isolated from the suppressive flax soil. It could inhibit the growth of many plant pathogens that were found in suppressive flax soil, and an acidic ethyl acetate extract of culture broth of the isolated Bacillus showed significant inhibition of the growth of some plant pathogens. The antimicrobial activity of culture extracts (15 times concentrated) was higher than that of 400 micrograms/ml actidione or 200 micrograms/ml mycostatin (nystatin). The antimicrobial substances were relatively stable. After heating at 100 degrees C for 10 min. and 30 min., the activities were still 100% and 72%, respectively. Properties of the compounds were investigated by UV, TLC, GC and GCMS. The component with the retention time of 13.4 min in a gas chromatography was biologically active and the parent peak was at m/z 142.

Induction of suppressor T cells by interleukin 2

The optimal concentration of interleukin 2 (IL 2) for maintaining the in vitro growth of T cells was quite different from that required for the induction of cytotoxic T lymphocytes (CTL) in nu/nu spleen cells. Higher concentrations of IL 2-containing preparations (10 to 30% v/v or 5 to 15 U/ml) were needed to promote the T cell growth, whereas lower concentrations (1 to 3% v/v or 0.5 to 1.5 U/ml) were needed to generate alloreactive CTL. It was further shown that the addition of high concentrations of IL 2 (10 to 30%) suppressed the generation of alloreactive CTL in conventional MLC. High concentrations of IL 2 induced the generation of antigen-nonspecific suppressor T cells in normal spleen cell cultures and augmented the generation of antigen-specific suppressor T cells in MLC. These suppressor cells suppressed the generation of CTL in fresh MLC and in polyclonal CTL cultures. These suppressor T cells could be induced by rat (spleen)-produced, murine (EL-4 cells) produced IL 2 preparations, and a purified human recombinant IL 2 (HR-IL2). The ability to induce suppressor cells correlated with the activity of IL 2 present in these preparations and was independent of their ability to induce cytotoxic effectors. These findings indicate that IL 2 may play a dual role in the regulation of CTL responses. We suggest that during antigen sensitization, the initial endogenous production of lower levels of IL 2 provided the second signal for the differentiation and proliferation of CTL. When higher levels of IL 2 were produced later, the suppressor T cell precursors were activated and differentiated into suppressor effectors to regulate the CTL response.

Induction of suppressor T cells by interleukin 2

The optimal concentration of interleukin 2 (IL 2) for maintaining the in vitro growth of T cells was quite different from that required for the induction of cytotoxic T lymphocytes (CTL) in nu/nu spleen cells. Higher concentrations of IL 2-containing preparations (10 to 30% v/v or 5 to 15 U/ml) were needed to promote the T cell growth, whereas lower concentrations (1 to 3% v/v or 0.5 to 1.5 U/ml) were needed to generate alloreactive CTL. It was further shown that the addition of high concentrations of IL 2 (10 to 30%) suppressed the generation of alloreactive CTL in conventional MLC. High concentrations of IL 2 induced the generation of antigen-nonspecific suppressor T cells in normal spleen cell cultures and augmented the generation of antigen-specific suppressor T cells in MLC. These suppressor cells suppressed the generation of CTL in fresh MLC and in polyclonal CTL cultures. These suppressor T cells could be induced by rat (spleen)-produced, murine (EL-4 cells) produced IL 2 preparations, and a purified human recombinant IL 2 (HR-IL2). The ability to induce suppressor cells correlated with the activity of IL 2 present in these preparations and was independent of their ability to induce cytotoxic effectors. These findings indicate that IL 2 may play a dual role in the regulation of CTL responses. We suggest that during antigen sensitization, the initial endogenous production of lower levels of IL 2 provided the second signal for the differentiation and proliferation of CTL. When higher levels of IL 2 were produced later, the suppressor T cell precursors were activated and differentiated into suppressor effectors to regulate the CTL response.

Amniotic rupture, extra-amniotic pregnancy, and vernix granulomata

is report describes two cases of amniotic rupture with delivery of live-born infants; one at 31 weeks and the other at term. The size of these amniotic sacs was apparently inadequate to contain the fetus, and extra-amniotic pregnancy was considered to have occurred. The ruptured and separated amniotic sacs were larger than previously reported examples and resembled those of delivery artifact. However, both placentas contained vernix granulomata in the separated amniotic mesenchyme and in the denuded mesenchyme of the chorionic plates, confirming the diagnosis of antepartum amniotic rupture. These observations add significant diagnostic criteria for identifying this entity in the absence of the hitherto commonly associated fetal amniotic band syndrome. Regardless of presence or absence of amniotic band syndrome, this entity is a sporadic condition, and recurrence is extremely rare in subsequent pregnancies.

Neuropathologic findings in thanatophoric dysplasia

Neuropathologic study of eight cases of thanatophoric dysplasia (dwarfism) reveals developmental abnormalities including hypoplasia of posterior fossa, megalencephaly, cerebral gyral disorganization, hippocampal malformation, neuronal heterotopia, nuclear dysplasia, and abnormal axonal bundles. There are no noticeable differences in CNS abnormalities between thanatophoric dysplasia with and without cloverleaf skull (Kleeblattschädel). The CNS abnormalities, likely the result of abnormal neuronal migration and cytoarchitectonic disarrangement, are apparently not caused by skeletal abnormalities. The observation suggests that CNS abnormalities represent a characteristic and distinct manifestation of thanatophoric dysplasia.

Cloning of the rat endogenous helper leukemia virus DNA sequence and expression of the helper activity encoded by the cloned DNA sequence in normal rat kidney cells by microinjection

By the use of recombinant DNA technology and microinjection in cultured cells, the molecular genetic elements involved in the evolution of a retrovirus with the multipotential to infect, transform and replicate in host cell, have been critically examined in this investigation. Recently we have identified and purified the integrated and proviral DNA sequences specific for two rat endogenous helper leukemia viruses, WR- RaLV , originated from a chemically induced wild rat fibrosarcoma, and RHHV , isolated from a chemically induced rat hepatoma, HTC-H1 (1). By using a multidisciplinary approach combining restriction endonuclease analysis, reverse phase V-column chromatography, agarose gel electrophoresis, Southern blot transfer and filter nucleic acid hybridization, we were able to demonstrate that the rat helper leukemia viral DNA sequence was approximately 8.4-8.8 kb. The 8.8 kb RHHV DNA was molecularly cloned via the EK-1 certified vector pBR 322 plasmid into E. coli RRI cells. A successful recombinant clone, 8/32, that carried one entire RHHV 8.8 kb DNA sequence was mapped by restriction endonuclease analyses. Restricted DNA fragments of various sizes throughout the complete RHHV genome were isolated and purified for intranuclear microinjection into normal rat kidney cells. Release of type C infectious helper virus in these microinjected cells was investigated by superinfection on K-NRK, Kirsten sarcoma transformed non-producer cells. Recombination of the helper viral DNA sequence, en toto or of subgenomic sizes, carried in microinjected cells, with the sarcomagenic DNA sequence, carried in K-NRK cells, was also studied by genome-rescue and cell-transformation experiments. Our observations led to the conclusion that all critical genetic elements including the 5' LTR helper DNA sequence, gag, pol, and env genes, encoded for the biological activity of the type C helper virus resided within the 6.0 kb proximal to the 5' terminus of the endogenous rat type C helper virus DNA. They proved vitally essential for the recombination with the Src sequence during the evolution of an infectious, transforming and replication-competent retrovirus.

Atheromatous embolization

Atheromatous emboli occur spontaneously or may be secondary to surgery or trauma. Thurlbeck and Castleman found a 77% incidence of atheromatous emboli to the kidney following the surgical repair of abdominal aortic aneurysms. Atheromatous debris may be dislodged following aortography, renal arteriography, and left heart catheterization via the right femoral artery. External trauma, including hip fracture, external cardiac message, and blunt abdominal trauma have initiated peripheral atheromatous embolization. The incidence of this phenomenon may be higher than documented in the literature, since it is difficult to establish the diagnosis prior to death. Atheromatous emboli should be suspected clinically in elderly patients with sudden onset of pain and ischemia of the lower extremities or unexplained renal failure. At the present time, multiple atheromatous emboli may be treated symptomatically only. Muscle biopsy, retinal examination, and kidney biopsy may be used to differentiate atheromatous embolization from other clinical entities.

Two lethal chondrodysplasias with giant chondrocytes

Two infants, each with a different form of sporadic lethal chondrodysplasia, had multinucleated giant chondrocytes in resting cartilage. Both patients also had severe laryngeal stenosis and normal chromosomes. The radiographic abnormalities in one patient conformed to the recently delineated entity, atelosteogenesis (spondylohumerofemoral hypoplasia or giant cell chondrodysplasia); the other patient had an unclassified type of spondyloepiphyseal dysplasia. The findings in these two patients and the previously reported observations in spondylohumerofemoral dysplasia confirm that chondrocytic giant cells are a causally nonspecific phenomenon.

Anatomic and clinical analysis of 96 Beall prostheses explanted over a 13-year period

Over 13 years, 96 Beall prostheses (80 Teflon, 16 Pyrolite) explanted at surgery were examined for durability, material wear, and clinical symptoms leading to surgical indication for excision were evaluated. The Teflon valves showed progressive disc wear and notching and two cases of disc escape from the cage; the Pyrolite discs were intact in all prostheses. The Dacron-Velour covering common to both types showed dehiscence at the inlet, significantly more severe after the third implant year in the Teflon (p less than 0.005) than in the Pyrolite prostheses. Sixty-nine (85 percent) cases with Teflon valves showed clinical manifestations of congestive heart failure due to prosthetic dysfunction; in 50 there was significant hemolytic anemia. Seven (44 percent) of the 16 Pyrolite disc valves were excised primarily because of dysfunction. The degree of hemolysis with the Pyrolite valves was usually mild. These data clearly suggested the advisability of early excision of the Beall Teflon prostheses in symptomatic patients and a close follow-up in patients with the Pyrolite models.

Nitrogen fixation in Klebsiella pneumoniae during osmotic stress. Effect of exogenous proline or a proline overproducing plasmid

Osmotic stress, imposed by 0.5 M NaCl or other electrolytes and non-electrolytes, caused over a 100-fold reduction in the whole-cell nitrogen fixation activity of Klebsiella pneumoniae, wild-type strain M5A1. This reduction of nitrogen fixation activity could be reversed by the addition of proline to the culture medium at 0.5 mM concentration. With 0.5 M NaCl, in the presence of proline, nitrogenase activity was 47-fold greater than in the absence of proline. A mutation, originally isolated in Salmonella typhimurium, which resulted in proline over-production and enhanced osmotolerance, was transferred into K. pneumoniae by F' conjugation. Intracellular proline, synthesized at high levels because of the mutation, had similar stimulatory effects on nitrogen fixation under osmotic stress as proline provided exogenously. In the overproducing strain, the cellular level of proline is elevated as much as 125-fold during stress over that seen in the control strain. To determine the mechanism of stimulation of nitrogen fixation by proline during stress, the biosynthesis of nitrogenase polypeptides was studied. Net nitrogenase biosynthesis and the biosynthesis of other unidentified peptides, is strongly inhibited during osmotic stress; proline reverses the inhibition. The role of proline in enhancing nitrogen fixation during osmotic stress is discussed.

Effect of interleukin 2 on cytotoxic effectors: I. Short-term culture of the cytotoxic effectors and the in vivo anti-tumor activity of the cultured effectors isolated from tumor site

The effects of interleukin 2 (IL2) on the in vitro and in vivo activity of cytotoxic T cells have been studied. IL2 was produced by W/Fu rat spleen cells cultured with concanavalin A. The IL2 thus prepared gave an optimal T-cell growth-promoting effect at a concentration of 5-20% equivalents of the original preparation. In the primary syngeneic mixed lymphocyte/tumor cell cultures (MLTC) against FBL-3 tumor cells, the addition of IL2 failed to generate a cytotoxic response. However, the cytotoxic response could be generated in MLTC by addition of exogenous macrophages. On the other hand, IL2 could maintain the growth of performed cytotoxic T cells for 3 to 5 weeks. These cytotoxic T cells were generated either by in vitro sensitization (MLC or MLTC) or by in vivo sensitization of B6 mice against a syngeneic tumor FBL-3. In short-term cultures, augmentation of the cytotoxic activity was seen after 10 days' culturing with IL2. The antigenic specificity of the cytotoxic reaction was altered after 28-35 days in culture, and the effectors broadly reactive. When growing a nonadherent population of lymphocytes isolated from FBL-3 ascites tumor, supplementation with IL2 selectively promoted the growth of a T-cell population, resulting in the elimination of the contaminating tumor cells. These purified T cells were highly cytotoxic for FBL-3 cells in vitro and also possessed strong in vivo anti-tumor activity against FBL-3 cells in the adoptive transfer experiments. The present study demonstrates that short-term culture (2-3 weeks) in IL2 promotes the growth of T cells and augments their cytotoxic activity with the appropriate antigenic specificity. IL2 also promoted the selective growth of T cells isolated from tumor site and these T cells showed augmented in vitro and in vivo anti-tumor activity.

Biological activity of cloned rat endogenous C-type virus DNA transferred by microinjection

The biological activity of a molecularly cloned DNA of a rat endogenous C-type leukaemia helper virus, RHHV, was assessed by intranuclear microinjection into normal rat kidney cells (NRK153). Release of rat C-type leukaemia helper viruses by the microinjected cells was examined by superinfection of Kirsten-transformed non-producer cells (K-NRK). Immediate release of helper leukaemia viruses at a very low level was observed only in the NRK153 m3 . 5/cir cells microinjected with the supercoiled form of RHHV DNA in toto, suggesting that the circular form of the virus DNA might have expedited the replication and expression of virus particles. Genome rescue experiments were also performed by co-cultivating the microinjected NRK153 m cells carrying various linear RHHV DNAs, in toto or of subgenomic sizes, with K-NRK cells. The results indicated that both the total and the 5.8 to 6.2 kb DNA fragment proximal to the 5' terminus of the cloned RHHV 8.8 kb DNA were able to rescue successfully a transforming replication-competent pseudotype virus. Subgenomic DNA fragments derived from the centre or the 3' end of the RHHV DNA were ineffective in the genome rescue experiments.

Molecular cloning of the endogenous rat C-type helper virus DNA sequence: structural organization and functional analysis of some restricted DNA fragments

Recently, we have identified and purified the integrated and proviral DNA sequences specific for two endogenous rat type C leukaemia helper viruses: WR-RaLV which originated from a fibrosarcoma induced in a feral rat and RHHV from the cell line HTC-H1 which originated from a Buffalo rat hepatoma. The rat leukaemia helper virus DNA sequences have previously been shown to be 8.4 to 8.8 kilobases (kb) in size. In this communication, we report the molecular cloning of the 8.8 kb DNA of RHHV by ligation at the BamHI site of the vector pBR322, cultured in an Escherichia coli RR1 host. After screening 5750 clones for ampicillin resistance and tetracycline sensitivity and testing by colony hybridization using 32P-labelled RHHV cDNA, four clones were isolated, two of which carried the total 8.8 kb DNA. A detailed restriction endonuclease map of the cloned RHHV DNA was deduced by sequential digestions of either 3'- or 5'-labelled DNA. Of the 14 restriction enzymes tested, EcoRI, BamHI, PstI, KpnI, TaqI, PvuII and SmaI gave informative cleavage patterns. At least two copies of long terminal repeated sequences (LTR) flanking the 3' and 5' termini of the proviral DNA were identified by TaqI and PstI cleavages. LTR in the rat endogenous leukaemia helper virus DNA measured 780 +/- 20 nucleotides in length. The genetic information encoded by the cloned DNA was also analysed by hybridization selection of RHHV mRNA, which was then used in cell-free protein synthesis in a rabbit reticulocyte lysate system. Essentially all major RaLV-specific proteins precipitable by anti-RaLV serum were synthesized in vitro, confirming that the RHHV genomic DNA was successfully cloned with little fidelity loss or scrambling of the genetic information.

Iron-molybdenum cofactor from nitrogenase. Modified extraction methods as probes for composition

Five modifications of the preparative procedure for isolating iron-molybdenum cofactor (FeMoco) from the molybdenum-iron (MoFe) protein of Azotobacter vinelandii nitrogenase have been developed. This variety of isolation methods has established that no single component of the original isolation protocol, i.e. Tris, Cl-, citrate, HPO4(2-), N,N-dimethylformamide, and N-methylformamide, is essential for the effective isolation and/or structural stability of FeMoco, although any of them may act as ligands to FeMoco when present. The acid-bse status (effective pH) of the extracting solvent is a key adjustable parameter in the isolation procedure. The new procedures produced FeMoco with yields, metal analysis, charge, EPR spectrum, and specific activity (after reconstituting crude extracts from A. vinelandii UW45 mutant cells) essentially identical with FeMoco isolated by the original procedure. After purification, FeMoco apparently contains molybdenum, iron, and sulfide in a 1:7:4 ratio with N-methylformamide as a ligand but no amino acid residues, common sugars, coenzyme A, or lipoic acid. Reaction with o-phenanthroline allows quantitation of both adventitious and FeMoco-associated iron. Correlations of total activity after UW45 reconstitution with molybdenum, total iron, and o-phenanthroline-resistant iron contents show that only the last gives a consistent relationship of 35 +/- 5 nmol of C2H4/min/ng atom of Fe. Both o-phenanthroline and EDTA interact with FeMoco to abolish its EPR signal in reactions reversible by additions of Fe2+ or Zn2+, respectively. These and related reactions point against the presence of an endogenous organic component in FeMoco and toward the presence of exogenous ligands and imply a relatively labile coordination sphere whose nature may be determinable by a systematic investigation.

Complete amino acid sequence of the 4Fe-4S, thermostable ferredoxin from Clostridium thermoaceticum

The complete amino acid sequence of the 4Fe-4S ferredoxin from the thermophilic bacterium Clostridium thermoaceticum has been determined. The protein is extremely thermostable and is the only known clostridial ferredoxin to contain a single [4Fe-4S] cluster. The sequence totals 63 residues and includes the first tryptophan (Trp-26) reported for a clostridial ferredoxin, and other amino acids not commonly found in clostridial or clostridial-like ferredoxins: methionine (Met-1), histidine (His-33), arginine (Arg-49), and leucine (Leu-9, -19, and -31). Sequence homology to clostridial and other 8Fe-8S ferredoxins is limited to eight to nine residues at the amino-terminal sulfhydryl grouping (Cys-10, -13, -16, and -20) and two to five residues in the carboxyterminal region. This ferredoxin is, thus, sequentially distinct from all known clostridial ferredoxins and from other bacterial ferredoxins in both the 8Fe-8S and 4Fe-4S classes.