Restriction fragment length polymorphisms of the angiotensinogen gene in inbred rat strains and mapping of the gene on chromosome 19q

Using a cDNA probe of the rat angiotensinogen gene (ANG), restriction fragment length polymorphisms (RFLPs) were detected in inbred rat strains with the restriction enzymes HindIII, PstI, and PvuII. Three alleles of ANG were almost equally distributed in 11 inbred strains. In two sets of backcross progeny originating from parental strains with different alleles, no close linkage was found between the ANG locus and 17 other loci tested. In situ hybridization, however, allowed assignment of the gene to chromosome 19q. The RFLPs of the angiotensinogen gene, therefore, can be considered useful as markers of rat chromosome 19.

Expression of glycoconjugates in intrahepatic cholangiocellular carcinoma

Twenty cases of intrahepatic cholangiocellular carcinoma (IHCCC) were studied by lectin histochemistry for their glycoconjugate expression. Combined alcian blue-peroxidic acid Schiff (ABPS) staining was also made for mucins in these tissues. Results showed that epithelial cells of intrahepatic bile ducts contained varied quantity of DBA, WGA, LCA, Con A, PHA, RCAI, BLAI, SJA, SBA, PSA and UEAI receptors but no PNA receptors. Lectin receptors were present at varying rates; 100% (Con A), 95% (PSA), 90% (LCA), 95% (WGA), 30% (BSAI), 35% (DBA), 65% (PHA), 74% (PNA), 85% (RCAI), 35% (SBA), 25% (SJA) and 55% (UEAI), respectively. The positive rates in well-differentiated IHCCC were significantly higher than those in either moderately or poorly-differentiated IHCCC. The distribution of lectin receptors in IHCCC was obviously different from that in peri-carcinomatous, cirrhotic and normal liver, and also differed from that in epithelial cells of normal intrahepatic bile ducts. All larger ducts were stained by ABPS and were mainly blue colour, while only 80% of IHCCC were positive for ABPS staining. Most of them were blue, others were red or purple. The results suggest that the expression of glycoconjugates had changed after the neoplastic transformation of bile duct cells.

Thymosin, interleukins, isoprinosine and imuthiol do not reconstitute T-cells in athymic nude mice

Previous reports suggest that immunotherapy can induce T-cell development in athymic nude mice. Eight-week-old BALB/c nu/nu (athymic nude) mice were treated for 3, 6 and 12 weeks with thymosin fraction 5 (TF-5), buffy coat interleukins (BC-IL), recombinant IL-2 (rIL-2), a combination of TF-5 and BC-IL, isoprinosine or imuthiol. Control animals were treated with sterile saline or were given a syngeneic thymus graft. Spleen weight, cell yields and Thy 1.2+ T-cell markers were monitored and spleen cell proliferative responses to rIL-2, concanavalin A (Con A), Con A + rIL-2, phytohemagglutinin (PHA) and endotoxin (LPS) were assessed. Only mice transplanted with a syngeneic thymus showed progressive increases in both T-cell number and function. Minor changes in proliferative responses were noted at 3 weeks with all treatments; however, no biologically significant reconstitution of T-cell number or function was observed.

Alternate pathways of DNA replication in Escherichia coli

We have described the pcbA1 mutation which enables E. coli cells to replicate DNA in the absence of a functional dnaE gene product if DNA polymerase I (the polA gene product) is present. The pcbA1 mutation phenotypically suppresses multiple dnaEts and dnaEam alleles. The pcbA1/PolI replication pathway differs from normal in sensitivity to certain DNA-damaging agents such as methylmethane sulfonate (MMS) and a lack of damage-directed mutagenesis. We report here cloning of the pcbA1 gene in a multicopy plasmid. The pcbA1 mutation is detected only in cis; therefore, cloning necessitated gene eviction. The pcbA1 gene lies closely- linked to gyrB. We have demonstrated the physical presence of DNA polymerase I in the replicating holoenzyme complex by immunoblotting using dnaEam strains. We conclude that E. coli has two alternate replisome structures: REP-A, in which DNA polymerase I is the functional synthetic subunit; and REP-E, in which the alpha-subunit, product of the dnaE gene, is functional. To investigate further the role of individual DNA polymerases in replication, we have isolated the polB gene on multicopy plasmids.

A comparison of bovine growth-hormone gene expression in mouse L cells directed by the Moloney murine-leukemia virus long terminal repeat, simian virus-40 early promoter or cytomegalovirus immediate-early promoter

Three transcriptional regulatory regions including a human cytomegalovirus immediate-early region (CMVIE) promoter, the simian virus-40 early region (SV40E) promoter, and Moloney murine leukemia virus (MoMLV) long terminal repeat (LTR) were ligated to the bovine growth hormone (bGH)-coding gene. Using a bGH transient expression system, the CMVIE and SV40E gene transcriptional regulatory regions were found to be approximately two-fold more efficient than the MoMLV LTR in directing expression of bGH in mouse L cells.

Regulation and expression of the multigene family coding light-harvesting chlorophyll a/b-binding proteins of photosystem II

The current state of knowledge concerning the expression of the nuclear genes that code the light-harvesting chlorophyll a/b-binding polypeptides of photosystem II is presented. This review covers the structure of these genes, the complex multistep pathway involved in their expression, and the environmental and other factors which regulate their expression. Some of the effects of these factors are mediated, at least in part, at the level of transcription, but other effects can be explained only by the existence of multiple posttranscriptional regulatory steps.

Using holographically generated corrector plates to fabricate low f/No. HOE objectives and collimators

We describe a double wavelength shift recording scheme for constructing holographic optical element (HOE) objectives and collimating lenses. The lenses are fabricated at intermediate wavelengths for use in a longer wavelength region. A holographic corrector plate is generated with a third wavelength that is the shortest of the three. Aberration of the HOE is compensated by inserting the corrector plate in one of the beams used in the construction process.

Bioprosthetic valve calcification and pseudoneointimal proliferation in bovine and ovine models

Both porcine (PX) and bovine pericardial (BP) valves have been used in the implantable Novacor left ventricular assist system (LVAS). Results from 58 chronic LVAS implants of greater than 7 days in calves and adult sheep are presented: the PX valve was used in 41 and the BP in 17. With PX valves, the maximum and mean assist durations were 161 and 54 days, respectively, in the calf and 279 and 129 days, respectively, in the sheep. The maximum and mean durations for BP valves were 93 and 38 days (calf) and 153 and 69 days (sheep). In bovine studies with PX valves, severe obstructive pseudoneointimal (PNI) proliferation in the Dacron inflow conduit was the primary cause for termination; valves exhibited moderate calcification. With BP valves, both PNI proliferation and severe valve calcification contributed to a declining pump output, leading to termination. In contrast to the bovine experience, PNI proliferation was not observed in ovine implants. BP valves still became calcified, as evidenced by a progressive decline in pump output (from about twelve weeks) and confirmed at termination. Valve calcification was minimal with the PX valves, even at 236 days. These results favor the adult ovine animal model for extended implants.

In vitro and in vivo testing of a totally implantable left ventricular assist system

The totally implantable Novacor LVAS is being tested under NIH auspices to demonstrate safety and efficacy before clinical trials. Twelve complete systems (submerged in saline at 37 degrees C) are being tested, with an NIH goal of demonstrating 80% reliability for 2 year operation with a 60% confidence level. The systems, which are continuously monitored, are diurnally cycled between two output levels by automatically varying preload and afterload. Currently, 14.3 years of failure-free operation have been accumulated, with a mean duration of 14 months. Using an exponential failure distribution model, the mean time to failure (MTTF) is greater than 8.8 years, corresponding to a demonstrated reliability (for a 2 year mission time) of 80% (80% confidence level). Recent ovine experiments with VAS subsystems include a 767 day volume compensator implant, a 279 day pump/drive unit implant and a 1,448 day BST implant. The last 12 chronic pump/drive unit experiments had a mean duration of 153 days (excluding early postoperative complications). This compares favorably with the NIH goals for complete systems (5 month mean duration). Complete system experiments are currently underway.

Sawtooth profile fringes with a two-grating interferometer

The theory of fringe formation of arbitrary profile in a two-grating interferometer is developed emphasizing sawtooth profile fringes. Two methods of fringe synthesis are given: the spatially incoherent illumination method, leading to a coherent synthesis and the temporally incoherent (polychromatic) illumination method, leading to an incoherent synthesis.