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Biomedical subjects

V Graziano

Publications and source records attributed to V Graziano.

At least 19 recordsLinked to original sources
PubMed2005

Leukocyte immunotherapy improves live delivery rates following embryo transfer in women with at least two previous failures: a retrospective review.

PURPOSE: To determine whether leukocyte immunotherapy (LIT) could improve live delivery rate following embryo transfer (ET) in women who were not successful in prior attempts. METHODS: Paternal leukocytes were intradermally injected in some women who had failed to have a successful pregnancy following at least two prior ETs approximately two weeks prior to fresh or frozen ET and repeated at the time of the 3rd rising serum beta human chorionic gonadotropin level and at eight weeks if a pregnancy occurred. Clinical pregnancy and live pregnancy rates (PRs) were compared to those women having ETs during the same time period not receiving LIT. RESULTS: Thirty-six of 94 (38.3%) patients receiving LIT (group 1) conceived following fresh or frozen ET vs 98 of 341 (28.7%) for women not receiving LIT (group 2) (p = NS). The live delivery rate per ET cycle was 30.8% (39/94) vs 19.7% for group 2 (p = .02). For the subset of women failing despite five previous ETs 17 of 37 (45.9%) group 1 women had a clinical pregnancy vs 18 of 64 (28.1%) group 2 women (p = .07%) and live delivery rates were 35.1% (13/37) vs 15.6% (10/64) (p = .024). CONCLUSIONS: These retrospective data encourage a prospective study of LIT combined with progesterone vs controls receiving progesterone only for recalcitrant patients having ETs.

Adult↗
PubMed2005

A comparison of luteal phase support in graduated estradiol/progesterone replacement cycles using intramuscular progesterone alone versus combination with vaginal suppositories on outcome following frozen embryo transfer.

PURPOSE: To compare pregnancy outcome following frozen embryo transfer according to type of progesterone (P) support given in the luteal phase. METHODS: Retrospective cohort analysis of frozen embryo transfer (ET) cycles in which ovulation was suppressed by graduated estradiol in the follicular phase. Two P regimens in the luteal phase were compared: P vaginal suppositories and intramuscular P vs intramuscular alone. RESULTS: The clinical and viable pregnancy rates were significantly higher for the women receiving only intramuscular P (57.6% and 43.7%) vs those receiving combined therapy (45.9% and 35.6%, respectively). The implantation rates were not significantly different (22.6% vs 19.5%). CONCLUSION: The increased pregnancy rates with intramuscular P may have been related to a higher number of embryos transferred (3.69 vs 3.26). Nevertheless, intramuscular P alone is at least as effective, if not more effective, than combined therapy for frozen embryo transfers.

Adult↗
PubMed2004

Neither sildenafil nor vaginal estradiol improves endometrial thickness in women with thin endometria after taking oral estradiol in graduating dosages.

PURPOSE: To determine if sildenafil improves endometrial thickness better than vaginal estradiol (E2) in women with a history of thin endometria. METHODS: Women failing to attain an 8 mm endometrial thickness on either the oocyte retrieval cycle or their first frozen embryo transfer (ET) despite an oral graduated E2 regimen were treated again with graduated oral E2 and were also randomly assigned to vaginal sildenafil or vaginal E2 therapy. Endometrial thickness was compared between the groups. RESULTS: Neither vaginal E2 nor sildenafil significantly improved endometrial thickness or blood flow in the subsequent frozen ET-cycle. CONCLUSIONS: These data fail to corroborate previous claims that 25 mg sildenafil four times daily intravaginally can improve endometrial thickness.

Administration, Intravaginal↗
PubMed2002

Structure of a yeast hypothetical protein selected by a structural genomics approach.

Yeast hypothetical protein YBL036C (SWISS-PROT P38197), initially thought to be a member of an 11-protein family, was selected for crystal structure determination since no structural or functional information was available. The structure has been determined independently by MIR and MAD methods to 2.0 A resolution. The MAD structure was determined largely through automated model building. The protein folds as a TIM barrel beginning with a long N-terminal helix, in contrast to the classic triose phosphate isomerase (TIM) structure, which begins with a beta-strand. A cofactor, pyridoxal 5'-phosphate, is covalently bound near the C-terminal end of the barrel, the usual active site in TIM-barrel folds. A single-domain monomeric molecule, this yeast protein resembles the N-terminal domain of alanine racemase or ornithine decarboxylase, both of which are two-domain dimeric proteins. The yeast protein has been shown to have amino-acid racemase activity. Although selected as a member of a protein family having no obvious relationship to proteins of known structure, the protein fold turned out to be a well known and widely distributed fold. This points to the need for a more comprehensive base of structural information and better structure-modeling tools before the goal of structure prediction from amino-acid sequences can be realised. In this case, similarity to a known structure allowed inferences to be made about the structure and function of a widely distributed protein family.

Alanine Racemase↗
PubMed1997

Characterization of the solution complex between the interferon-induced, double-stranded RNA-activated protein kinase and HIV-I trans-activating region RNA.

The antiviral activity of the interferon-induced, double-stranded RNA (dsRNA)-activated protein kinase (PKR) is mediated through dsRNA binding leading to PKR autophosphorylation and subsequent inhibition of protein synthesis. Previous biochemical studies have suggested that autophosphorylation of PKR occurs via a protein-protein interaction and that PKR can form dimers in vitro. Using four independent biophysical and biochemical methods, we have characterized the solution complex formed between PKR and trans-activating region (TAR) RNA, a 57-nucleotide RNA species with double-stranded secondary structure derived from the human immunodeficiency virus type I genome. Chemical cross-linking and gel filtration analyses of PKR.TAR RNA complexes reveals that TAR RNA addition increases PKR dimerization and results in the formation of a solution complex with a molecular weight of approximately 150,000. Addition of TAR RNA to PKR results in a quenching of tryptophan fluorescence, indicative of a conformational shift. Through small angle neutron scattering analysis, we show that PKR exists in solution predominantly as a dimer, and has an elongated solution structure. Addition of TAR RNA to PKR causes a significant conformational shift in the protein at a 2:1 stoichiometric ratio of protein to RNA. Taken together, these data indicate that the PKR activation complex consists of a protein dimer bound cooperatively to one dsRNA molecule.

Base Sequence↗
PubMed1996

Identification of two DNA-binding sites on the globular domain of histone H5.

The nature of the complexes of histones H1 and H5 and their globular domains (GH1 and GH5) with DNA suggested two DNA-binding sites which are likely to be the basis of the preference of H1 and H5 for the nucleosome, compared with free DNA. More recently the X-ray and NMR structures of GH5 and GH1, respectively, have identified two basic clusters on opposite sides of the domains as candidates for these sites. Removal of the positive charge at either location by mutagenesis impairs or abolishes the ability of GH5 to assemble cooperatively in 'tramline' complexes containing two DNA duplexes, suggesting impairment or loss of its ability to bind two DNA duplexes. The mutant forms of GH5 also fail to protect the additional 20 bp of nucleosomal DNA that are characteristically protected by H1, H5 and wild-type recombinant GH5. They still bind to H1/H5-depleted chromatin, but evidently inappropriately. These results confirm the existence of, and identify the major components of, two DNA-binding sites on the globular domain of histone H5, and they strongly suggest that both binding sites are required to position the globular domain correctly on the nucleosome.

Amino Acid Sequence↗
PubMed1996

Neutron scattering studies on chromatin higher-order structure.

We have been engaged in studies of the structure and condensation of chromatin into the 30 nm filament using small-angle neutron scattering. We have also used deuterated histone H1 to determine its location in the chromatin 30 nm filament. Our studies indicate that chromatin condenses with increasing ionic strength to a limiting structure that has a mass per unit length of 6-7 nucleosomes/11 nm. They also show that the linker histone H1/H5 is located in the interior of the chromatin filament, in a position compatible with its binding to the inner face of the nucleosome. Analysis of the mass per unit length as a function of H5 stoichiometry suggests that 5-7 contiguous nucleosomes need to have H5 bound before a stable higher order structure can exist.

Animals↗
PubMed1995

Prokaryotic translation initiation factor IF3 is an elongated protein consisting of two crystallizable domains.

We show that translation initiation factor IF3 can be split into two fragments of nearly equal size by the Escherichia coli outer membrane protease omptin. Circular dichroism and small-angle neutron scattering show that the two fragments are structured as domains. Each domain is relatively compact, and they are separated by about 45 A in intact IF3. Thus IF3 is an elongated protein that consists of two well-separated domains. We suggest that these two domains are involved in ribosome binding across the cleft of the 30S ribosome. We also report the crystallization of each domain of IF3.

Circular Dichroism↗
PubMed1994

Histone H1 is located in the interior of the chromatin 30-nm filament.

The linker histone H1 binds to the nucleosome and is essential for the organization of nucleosomes into the 30-nm filament of chromatin. It has been implicated in the repression of transcription, and phosphorylation of H1 may be involved in cell-cycle-dependent chromatin condensation and decondensation. A long-standing issue concerns the location of H1 in the chromatin filament. The original solenoidal model proposes that H1 is inside the 30-nm filament, but other models, also helical, suggest a variable or more accessible location for H1. Investigations to determine the location of the linker histone based on its accessibility to antibodies or immobilized proteases under various ionic conditions have yielded conflicting results. Here we use neutron scattering in a direct structural determination to show that H1 is located in the interior of the filament.

Chromatin↗
PubMed1994

Expression of chicken linker histones in E. coli: sources of problems and methods for overcoming some of the difficulties.

Expression of histones in Escherichia coli is important in structural studies on chromatin, because it allows isotopic labeling such as deuteration and replacement of methionines with selenomethionine as well as expression of specific domains of histones. We show that full-length H5 cannot be expressed in E. coli. We have determined that the problem is translational rather than transcriptional. Pulse-labeling studies show that protein turnover is not the reason for lack of accumulation. On dissecting the gene, we find that the problem lies in expressing the highly charged C-terminal tail of H5. We can make progressively increasing amounts of the tail, but at the point where over two-thirds of this region is transcribed, the protein ceases to be made. Surprisingly, full-length H1 is made. In vitro studies show that the H5 gene can be translated in a rabbit reticulocyte system but not in an E. coli system, suggesting that there may be a difference in the ability of eukaryotic and prokaryotic ribosomes to translate this message. The expression of the globular domains of H5 and H1 posed a different problem. There was little or no expression of some of the constructs, even though they were fragments of larger constructs that were well made. Replacement of the first five codons downstream of the initiating ATG codon with those optimized for E. coli, and which were AT rich, restored expression. This may have general implications for expression of eukaryotic proteins in E. coli.

Amino Acid Sequence↗
PubMed1993

Crystal structure of globular domain of histone H5 and its implications for nucleosome binding.

The structure of GH5, the globular domain of the linker histone H5, has been solved to 2.5 A resolution by multiwavelength anomalous diffraction on crystals of the selenomethionyl protein. The structure shows a striking similarity to the DNA-binding domain of the catabolite gene activator protein CAP, thereby providing a possible model for the binding of GH5 to DNA.

Amino Acid Sequence↗
PubMed1992

Alkaptonuria and renal failure: a case report and review of the literature.

In alkaptonuric ochronosis, the absence of homogentisic acid oxidase results in the accumulation of homogentisic acid in the body. Associated renal failure is rare and usually occurs in the later stages of the disease. We report a 19-yr-old girl who presented initially with severe renal failure, without family or past history of illness. There was no significant proteinuria or hematuria. No clinical evidence of pigmentation such as skin and subcutaneous cartilages was noted. However, pigment deposits were identified in the renal biopsy specimens obtained within a week after admission and another after a month. Two months later the peritoneal dialysis fluid and skin progressively darkened, suggesting ochronosis. This was confirmed by the detection of homogentisic acid in the serum and urine. The patient expired in renal failure. Renal biopsy tissues showed diffuse chronic tubulo-interstitial disease characterized by widespread tubular atrophy, interstitial fibrosis, and a moderate degree of inflammation. Many tubular cells contained brown, coarsely granular ochronotic pigment (OP) and a few pigment casts were in the lumina. Similar deposits were also in the interstitium and within histiocytes. Ultrastructural studies of the glomeruli revealed small sparse OP deposits in the visceral and parietal epithelial cells, mesangial cells, and rare extracellular and basement membrane deposits. The tubulointerstitial changes were varied: atrophy and dilatation of tubules, varying degrees of lysosomal OP and degeneration of tubular cells, casts containing OP with crystalline material, histiocytes distended with OP, and free interstitial pigment deposition.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

Interaction of HMG14 with chromatin.

Neutron scattering has been used to study the interaction of HMG14 with chromatin. Chromatin depleted of H1/H5 was reconstituted separately with histones H1 and H5, and complexed with HMG14. We have also studied the conformation of complexes formed by the binding of HMG14 to nucleosome dimers without linker DNA. Our data on the binding of HMG14 to linkerless nucleosome dimers argue against a significant change in the exit and entry angles of nucleosomal core DNA. Data on the condensation of chromatin into a higher-order structure suggest that there is no dramatic difference between the roles of H1 and H5 in their influence on HMG14 complex formation. However, there is a decrease of about 25% in the mass per unit length of chromatin fibers on HMG14 binding, which is not accompanied by a change in the fiber repeat distance. This is evidence that there are fewer nucleosomes per repeat in HMG14 containing chromatin fibers than in normal chromatin. Alteration of chromatin structure in this manner may be part of the role of HMG14 in actively transcribed chromatin.

Animals↗
PubMed1990

Crystallization of the globular domain of histone H5.

The globular domain of histone H1/H5 binds to the nucleosome and is crucial for the formation of chromatin higher order structure. We have expressed in Escherichia coli a gene that codes for the globular domain of H5. The protein produced in E. coli is functional in nucleosome binding assays. We have obtained crystals of the protein that diffract to beyond 2.5 A (1 A = 0.1 nm) resolution. The crystals are orthorhombic with unit cell dimensions of a = 80.1 A, b = 67.5 A and c = 38.0 A.

Crystallization↗
PubMed1988

Reconstitution of chromatin higher-order structure from histone H5 and depleted chromatin.

Reconstitution of the 30 nm filament of chromatin from pure histone H5 and chromatin depleted of H1 and H5 has been studied using small-angle neutron-scattering. We find that depleted, or stripped, chromatin is saturated by H5 at the same stoichiometry as that of linker histone in native chromatin. The structure and condensation behavior of fully reconstituted chromatin is indistinguishable from that of native chromatin. Both native and reconstituted chromatin condense continuously as a function of salt concentration, to reach a limiting structure that has a mass per unit length of 6.4 nucleosomes per 11 nm. Stripped chromatin at all ionic strengths appears to be a 10 nm filament, or a random coil of nucleosomes. In contrast, both native and reconstituted chromatin have a quite different structure, showing that H5 imposes a spatial correlation between neighboring nucleosomes even at low ionic strength. Our data also suggest that five to seven contiguous nucleosomes must have H5 bound in order to be able to form a higher-order structure.

Animals↗
PubMed1986

A role for proteins S3 and S14 in the 30 S ribosomal subunit.

Small ribosomal subunits prepared by the method of Kirillov et al. (Kirillov, S. V., Makhno, V. I., Peshin, N. N., and Semenkov, Yu. P. (1986) Nucleic Acids Res. 5, 4305-4315) are active but fail to reconstitute. The inability to reconstitute is due to a deficiency in proteins S3 and S14. Supplementation of the protein component with pure S3 and S14 leads to an enhancement of the activity of the reconstituted product. Our results provide evidence that these two proteins are involved in assembly but may not be required once the 30 S subunit has been properly assembled.

Escherichia coli↗