Effects of repetitive and non-repetitive rat rDNA enhancer elements on in vivo transcription by RNA polymerases I and II

Previous study has demonstrated that a far upstream 174-bp spacer sequence of the rat rRNA-encoding (rDNA) gene can function as an enhancer in vitro in an orientation- and distance-independent manner [Dixit et al., J. Biol. Chem. 262 (1987) 11616-11622]. To demonstrate that this element can also function in vivo, two rat rDNA-cat plasmids, one with the 174-bp element and the other without this sequence, were constructed and transfected into CHO cells. Primer extension analysis of the transcripts produced after transfection showed that transcription initiation occurred at the +1 site of the rDNA. The 174-bp sequence stimulated the rat polI promoter activity in cis 4-5-fold over the control (with the promoter alone). This RNA polymerase (polI) enhancer also stimulated the mouse metallothionein-I (MT-I) and SV40 promoter activities in vivo, irrespective of its distance and orientation. Further dissection of the 174-bp element revealed that the stimulatory activity on the RNA polymerase II (polII) promoter resides within the 37-bp and 43-bp domains at the 3' end of the 174-bp element. Unlike this spacer enhancer, the 130-bp repeat element (RE) proximal to the rat promoter [Ghosh et al., Gene 125 (1993) 217-222] was unable to modulate the polII promoter activity in vivo. These data show that while the non-repetitive enhancer sequence of rat rDNA is interchangeable for the polI and polII promoters, the RE is polI-specific.

The development of cyclic sulfolanes as novel and high-affinity P2 ligands for HIV-1 protease inhibitors

Design and synthesis of a novel series of protease inhibitors incorporating conformationally constrained cyclic ligands for the S2-substrate binding site of HIV-1 protease is described. We recently reported urethanes of 3-tetrahydrofuranyl as P2 ligands for HIV-1 protease inhibitors. Subsequently, we have found that the urethane of 3(S)-hydroxysulfolane further increased the in vitro potency of these inhibitors. Furthermore, introduction of a small 2-alkyl group cis to the 3-hydroxyl group of either heterocyclic system further enhanced enzyme affinity. The cis-2-isopropyl group thus far offered optimum enhancement of the inhibitory properties. This led to the discovery of inhibitor 43 (IC50 3.5 nM, CIC95 50 +/- 14 nM) of comparable in vitro antiviral potency to the current clinical candidate 1 (Ro 31-8959) but of reduced molecular weight due to the exclusion of the P3 quinoline ligand. Also, it has been demonstrated that the octahydropyrindene derivative 34 is an effective replacement of the P1' decahydroisoquinoline derivative.

Effect of hypervitaminosis A on intestinal digestive & absorptive functions in rat

Oral administration of large doses of retinol to young rats significantly accelerated glucose and galactose uptake in small intestinal segments. It also augmented both total and specific activities of brush border membrane associated disaccharidases and blood glucose level. For this investigation the intestine was examined in three segments viz., proximal, mid and distal portion and also as a whole. In comparison with matched controls, total enzymic activities in with hypervitaminosis A animals were nearly double for lactase, sucrase and maltase in all segments. With specific enzymic activities, the change in enzymic activities were greater for lactase and maltase, but less for sucrase.

Enhancer 1 binding factor, a Ku-related protein, is a positive regulator of RNA polymerase I transcription initiation

We have previously characterized a protein, enhancer 1 binding factor (E1BF), from rat cells that can modulate RNA polymerase I-directed transcription of the rat rRNA gene in vitro. E1BF, a heterodimeric DNA binding protein composed of 72-kDa and 85-kDa subunits, is related to the human Ku autoantigen with respect to immunological and certain structural properties. To establish the direct role of E1BF in transcription, we investigated the effect of anti-Ku antibodies on RNA polymerase I-directed transcription in rat and mouse cell extracts. These antibodies, one directed against the 70-kDa Ku subunit and the other against a peptide fragment of this subunit, dissociated the E1BF heterodimer into its two subunits. The DNA-protein complex formed in the presence of the antibodies contained only the 72-kDa subunit. Preincubation of the extracts with these antibodies resulted in an almost complete inhibition of transcription. The reduced transcription was observed when either linear or circular template was used. The inhibitory effect of the antibodies was greatest when added prior to preinitiation complex formation and was minimized significantly when added after establishment of the initiation complex. The repression of rRNA gene transcription was overcome by the addition of purified E1BF. This study demonstrates that E1BF, a Ku-related protein, is required for RNA polymerase I-directed transcription, the 72-kDa subunit is the major DNA binding polypeptide, the factor acts primarily in the formation of the preinitiation complex, and heterodimerization of its two subunits is crucial for maintaining the functional integrity of the protein.

Acute renal failure in a patient with HELLP syndrome--an unusual complication of eclampsia

Acute renal failure occurring in a 24-year-old primigravida with eclampsia and HELLP (hemolysis, elevated liver enzymes, low platelets) syndrome is described. She also had transient disseminated intravascular coagulation. Hemodialysis, fresh blood transfusions, and antihypertensive therapy were administered, and resulted in complete recovery. Kidney biopsy revealed acute tubular necrosis.

Acute renal failure in a case of fatal chromic acid poisoning

Despite its frequent use in industry, acute poisoning by chromic acid has very rarely been reported. We report a patient who developed massive gastrointestinal hemorrhage, acute renal failure, and hepatic injury following chromic acid ingestion, and subsequently died. Postmortem liver and kidney biopsies revealed centrilobular necrosis and severe acute tubular necrosis, respectively.

A fluorescence anisotropy study of stabilizing effect of tri- and tetra- nitrovasodilatory drugs on DPPC liposomal membrane

Glyceryl trinitrate (GT) and pentaerythritol tetranitrate (PT) are two vasodilatory drugs. The physical properties of the membrane lipid matrix, which determine the structure and function of the membrane-bound proteins, generally control the perturbation mechanism of these drugs. Thus, physical interaction of these drugs with membrane lipids is very crucial for their clinical use, different cellular processes, as well as for targetted drug delivery systems. In the present paper, we have reported for the first time the interaction between these drugs and the lipid molecules in the liposomal system of dipalmitoylphosphatidyl-choline (DPPC), as measured by steady-state fluorescence anisotropy using 1,6-diphenyl-1,3,5-hexatriene (DPH) as fluorescent probe. Our results show that by dissolving in the lipid matrix these two drugs effectively stabilise the liposomal membrane: the effect being more in case of GT than in PT, indicating that the rigidifying effect is independent of the number of nitrate groups of the two drugs. This effect increases with the increase in drug concentration, implying solubilisation of all drug molecules. Though our in vitro study has more physical significance than a physiological one, the results obtained here may be used to interpret the effects that are observed in vivo.

Non-surgery related aspergillus native valvular endocarditis: report of two cases

Two unusual cases of aspergillus valvular endocarditis without any history of cardiovascular surgery found at autopsy are reported. As there is a chance of dissemination, early diagnosis is important. Clinical awareness can lead to early recognition and effective treatment of this potentially lethal condition.

Optimization of alignability in integrated planar-optical interconnect packages

The efficiency of power transfer and the alignability of an integrated planar-optics holographic optical backplane for board-to-board interconnections are analyzed. Both the efficiency and the alignability are functions of lateral and angular offsets in the input, the error in the spatial frequency of the hologram, errors in the source wavelength, the distance between two boards, the thickness of the substrate, the sizes of the hologram and the beam spot, and the angle of propagation of the beam. From the analyses, design guidelines on integrated planar-optic interconnects are developed, and it is shown that the interconnect design can be optimized for maximum alignability. A design with optimum alignability may not have the highest possible peak efficiency, but it can tolerate greater offsets without a substantial efficiency decrease.

Evaluation of a sports specific training programme in badminton players

We studied the effect of a short three week programme, dominated by specific training, on the aerobic capacity (VO2 max) and ventilatory anaerobic threshold (VanT) of badminton players and also to evaluate the intensity of the specific training on the basis of heart rate and blood lactate concentration. The study was conducted on five women badminton players (age 13-14 yr; height 160-165 cm and weight 47.0-51.5 kg) who were semifinalists in the 1988 subjunior or junior national championships. The VO2 max and VanT were determined at the commencement and at the cessation of the training. The VO2 max was evaluated on an automatic analyser during a graded running protocol on a treadmill and VanT was determined by the gas exchange method from the VE-VO2 relationship. The three week programme was dominated by specific training, apart from other conditioning programme. The mean VO2 max was found to improve from 2.11 l/min (43.8 ml/kg/min) to 2.24 l/min (46.4 ml/kg/min), while the VO2 at VanT improved from 1.48 l/min (30.8 ml/kg/min) to 1.68 l/min (33.7 ml/kg/min). The improvement in both was statistically significant. The mean heart rate and blood lactate concentration during the specific training were 161 b/min and 3.9 mM/l respectively while training with the shuttlecock and 185 b/min and 6.2 mM/l respectively during shadow practice. The findings indicated that the intensity of specific training was quite high, varying from aerobic-anaerobic transition level to aerobic overload region and was able to alter the VO2 max and VanT of the players, even with a short precompetition training.

Distinct superinfection interference properties yet similar receptor utilization by cytopathic and noncytopathic feline leukemia viruses

Cell killing by cytopathic retroviruses is often associated with a delay or failure in the establishment of superinfection interference. Superinfection has been observed during T-cell killing and fatal immunodeficiency disease induction by the feline leukemia virus (FeLV) chimera FeLV-FAIDS-EECC, containing the surface envelope glycoprotein (SU) of FeLV-FAIDS clone 61C. We demonstrate here that 61C SU has a defect that results in a nearly complete failure to establish superinfection interference against homologous virus challenge. This failure was evident only in feline T (FeT) cell clones expressing envelope protein, not in the rare cells that have survived cytopathic infection to become chronically infected. The regions of SU responsible for this defect were the same as those previously identified as responsible for T-cell killing. The superinfection interference properties of a noncytophatic molecular clone, FeLV-FAIDS-61E, were different in that 61E established interference to homologous virus challenge, both in SU-expressing cell clones and in chronically infected cells. Neither 61E nor EECC established interference against heterologous virus challenge. Viruses expressing chimeric SU proteins displayed varied and intermediate interference properties. Purified 61E and 61C SU competed for binding sites on FeT cell surfaces, and purified 61E SU blocked infection of virus bearing 61E or 61C SU. In addition, purified 61E and 61C SU each coprecipitated 70-kDa FeT cell surface proteins. Our data are consistent with the hypothesis that there are multiple cellular components necessary for 61E and 61C attachment to and penetration of FeT cells, a primary receptor that is utilized by both 61E and 61C, and secondary receptors that are likely to be virus specific.

Potent HIV protease inhibitors: the development of tetrahydrofuranylglycines as novel P2-ligands and pyrazine amides as P3-ligands

A series of protease inhibitors bearing constrained unnatural amino acids at the P2-position and novel heterocycles at the P3-position of compound 1 (Ro 31-8959) were synthesized, and their in vitro enzyme inhibitory and antiviral activities were evaluated. Replacement of P2-asparagine of compound 1 with (2S,3'R)-tetrahydrofuranylglycine resulted in improvement in enzyme inhibitory as well as antiviral potencies (compound 23). Interestingly, incorporation of (2S,3'S)-tetrahydrofuranylglycine at the P2-position proved to be less effective. The resulting compound 24 was 100-fold less potent than the 2S,3R-isomer (compound 23). This stereochemical preference indicated a hydrogen-bonding interaction between the tetrahydrofuranyl oxygen and the residues of the S2-region of the enzyme active site. Furthermore, replacement of P3-quinolinoyl ligand of 1 with various novel heterocycles resulted in potent inhibitors of HIV proteases. Of particular interest, compound 2 with (2S,3'R)-tetrahydrofuranylglycine at P2 and pyrazine derivative at P3 is one of the most potent inhibitors of HIV-1 (IC50 value 0.07 nM) and HIV-2 (IC50 value 0.18 nM) proteases. Another important result in this series is the identification of compound 27 in which the P2-P3-amide carbonyl has been removed. The resulting compound 27 has exhibited improvement in antiviral potency while retaining the enzyme inhibitory potency similar to compound 1.

Lack of association of HLA polymorphisms with human papillomavirus-related cervical cancer

An association of HLA-DQ3 with SCC of the cervix has been reported by researchers in Germany and Norway. This article documents a similar-sized study with patients and controls from northwest England. We report in detail on serologically determined HLA polymorphism in SCC patients with respect to HPV 16 infection, MHC class II expression within the tumor, serologic response to HPV, and other relevant clinical variables. We have also extended our studies to include DNA-based analysis using PCR and SSO probes for HLA-DQ. No significant association of any HLA-A, -B, -C, -DR, or -DQ antigen with SCC patients was found. While a possible explanation of the differences among studies could be a reflection of disease heterogeneity, the several tumor and clinical factors examined do not account for the observed differences from previous reports. Further studies are needed for a greater understanding of the interaction of HPV and HLA type in the development of cervical neoplasia.

Pancreatic pseudocyst. A rare complication of polyarteritis nodosa

An 18-year-old male who developed a pancreatic pseudocyst during the active phase of polyarteritis nodosa is described. Cytotoxic therapy with cyclophosphamide and prednisolone was unable to control the manifestation of this disease, and he required percutaneous drainage of the pseudocyst. The drainage resulted in complete resolution.

A phase I study of recombinant human interleukin-4 administered by the intravenous and subcutaneous route in patients with advanced cancer: immunological studies

The effects of recombinant human interleukin-4 (rhu IL-4) on immunological parameters in patients receiving increasing doses of IL-4 in a Phase I trial were investigated. Peripheral blood mononuclear cells were phenotyped for a variety of lymphocyte markers, but no consistent effects were observed. However, increases in HLA Class II expression on monocytes were detected in four patients. NK and LAK activity were neither induced nor augmented by IL-4 treatment. Slight increases in proliferative responses to mitogens and cytokines were observed in some patients. The latter observations and other clinical studies suggest that a combination of IL-4 with IL-2 may be more effective in Phase II clinical trials.

Characterization of the 130-bp repeat enhancer element of the rat ribosomal gene: functional interaction with transcription factor E1BF

The 130-bp repetitive element (RE) of the rat rDNA (ribosomal RNA-encoding gene) intergenic spacer stimulated the synthesis of rRNA four- to sixfold, in comparison with that of the promoter alone, both in vivo and in vitro, when ligated to the rat rDNA promoter. The addition of increasing amounts of highly purified E1BF (enhancer-1 binding factor), which binds to the rat rDNA promoter and an upstream nonrepetitive enhancer element [Zhang and Jacob, Mol. Cell. Biol. 10 (1990) 5177-5186], to an in vitro transcription system resulted in enhancement of rDNA transcription from the recombinant plasmids containing the promoter or promoter-RE. However, E1BF-mediated stimulation of transcription under the influence of the RE continued at higher concentrations of E1BF than did the control transcription from the promoter alone. The binding affinity of E1BF for the RE was comparable to its affinity for the nonrepetitive far upstream enhancer element previously characterized in our laboratory. The sequences protected by E1BF in the RE differed from those protected by UBF (upstream control element-binding factor), a well characterized pol I transcription factor. These data suggest that E1BF belongs to a class of transcription factors which interact with the promoter and spacer cis-acting RE to modulate rDNA transcription.

Disseminated tuberculosis in a renal transplant recipient presenting as a non-healing skin ulcer. A case report

Cutaneous tuberculosis in renal allograft recipients is rare. A 33 year old recipient of a second renal allograft developed a painless ulcer on the left foot two months after surgery, followed by the appearance of a cold abscess in the left inguinal region. Smear from the pus aspirated from this abscess revealed acid fast bacilli, and biopsy from the edge of the ulcer showed an epithelioid cell granuloma with Langhans type of giant cells. X-ray of the chest revealed miliary mottling in both lung fields. Antitubercular therapy lead to a complete resolution of the tuberculous lesions.