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Biomedical subjects

R Mantovani

Publications and source records attributed to R Mantovani.

At least 55 records · Page 3Linked to original sources
PubMed1996

The effects of clonidine on blood pressure, catecholamine and growth hormone release in hypogonadal men is preserved and not influenced by testosterone replacement therapy.

It has been demonstrated that castration impairs the hypotensive effect of clonidine in rat as well as its GH-releasing activity while testosterone replacement restores to normal the effects of alpha-2 adrenoceptor activation. Thus, these data point to main role of the gonadal steroid testosterone in modulating the effects of alpha-2 adrenergic activation on blood pressure, catecholamine and GH release in animal. Aim of the present study was to verify the activity of clonidine on blood pressure, catecholamine and GH release in human male hypogonadism before and after testosterone replacement. To this goal, 14 hypogonadal men (HP, age 33.8 +/- 2.9 yr; BMI < 25 kg/m2; 8 with hypergonadotropic and 6 with hypogonadotropic hypogonadism) received clonidine administration (CLON, 300 micrograms po at 0 min) before and after 3 months of testosterone replacement (testosterone propionate depot, 250 mg i.m. every 21 days). Ten normal adult volunteers (NS, age 31.5 +/- 1.9 yr; BMI < 25 kg/m2) were studied as control group. In all subjects, before and after clonidine administration, systolic and diastolic blood pressure (SBP and DBP), pulse rate (PR), norepinephrine (NE), epinephrine (E) and GH levels were recorded. In HP basal testosterone levels were lower than those in NS (1.25 +/- 0.3 vs 7.34 +/- 1.5 ng/ml, p < 0.05) and were restored to normal by hormonal replacement (6.91 +/- 1.3 ng/mL) in HP, both SBP and DBP as well as PR were normal in basal conditions and were not modified by testosterone replacement. Both before and during testosterone CLON lowered SBP, DBP and PR in HP to the same extent observed in NS. In HP, basal NE levels were lower than those in NS (0.85 +/- 0.15 vs 1.28 +/- 0.19 nmol/l, p < 0.05) and were restored to normal during testosterone replacement (1.25 +/- 0.13 nmol/l). On the other hand, basal E levels in HP were similar to those in NS (179 +/- 42 vs 197 +/- 38 pmol/l) and were not modified by testosterone therapy (167 +/- 28 pmol/l). In HP, both before and during testosterone replacement, CLON reduced NE (0.44 +/- 0.10 and 0.58 +/- 0.07 nmol/l) levels to the same levels recorded in NS (0.68 +/- 0.08 nmol/l). Basal GH and IGF-I levels in HP (1.15 +/- 0.5 and 234 +/- 42 micrograms/l, respectively) were similar to those in NS (1.18 +/- 0.4 and 221 +/- 38 micrograms/l, respectively) and were not modified by testosterone (1.35 +/- 0.6 and 256 +/- 32 micrograms/l, respectively). CLON administration induced a clear GH response in HP (F = 37; p < 0.001) which overlapped with that recorded in NS and was not modified by testosterone (F = 1.7; P = NS). Our present findings demonstrate that, differently from in animal, in man testosterone has no role in modulating the effects of alpha-2 adrenergic activation by clonidine on blood pressure, catecholamine and GH release. On the other hand, our data suggest the existence in male hypogonadism of a reduced basal noradrenergic activity which is restored by testosterone replacement.

Adult↗
PubMed1996

Cloning of Schistosoma mansoni transcription factor NF-YA subunit: phylogenic conservation of the HAP-2 homology domain.

The CCAAT-binding factor NF-Y (CBF/CP1) is a heteromeric transcription factor involved in the regulation of a variety of eukaryotic genes. We identified NF-Y as the CCAAT activity binding to the promoter region of the gene coding for the 28-kDa glutathione S-transferase of the human parasite Schistosoma mansoni (Sm28GST). We isolated the NF-YA cDNA from S. mansoni (SmNF-YA): the complete 268 amino acid sequence harbors a region in its C-terminal part that shows homology with the subunit interaction and DNA-binding domains of the mammalian NF-YA; the N-terminal region has an amino acid composition reminiscent of the mammalian and echinoderm counterparts, rich in glutamine and hydrophobic residues, but shows no sequence similarity at the primary level. In vitro synthesized SMNF-YA is able to associate with mammalian NF-YB/C subunits in the absence of DNA and to bind to the Sm28GST CCAAT box. Surprisingly, a monoclonal antibody directed against the non-conserved Q-rich activation domain of mammalian NF-YA supershifts and immunoprecipitates SMNF-YA, strongly suggesting structure conservation in the activation domain between divergent species.

Amino Acid Sequence↗
PubMed1996

The major histocompatibility complex class II Ea promoter requires TFIID binding to an initiator sequence.

The major histocompatibility complex (MHC) class II Ea promoter is dependent on the presence of conserved upstream X and Y boxes and of initiator (Inr) sequences. In vitro transcription analysis of the Inr region with linker-scanning mutants pinpoints a functionally essential element that shows homology to the terminal deoxynucleotidyltransferase (TdT) Inr; contrary to the TdT Inr and other Inrs identified so far, the key sequence, between positions +5 and +12, is located within a transcribed area. Swapping the TdT sequence into the corresponding Ea position leads to a fivefold increase in transcription rate, without altering start site selection. Inr-binding proteins LBP-1/CP2 and TIP--a TdT Inr-binding protein unrelated to YY1--recognize the Ea Inr; they interact with overlapping yet distinct sequences around the Cap site, but their binding does not coincide with Ea Inr activity. A good correlation is, rather, found with binding of immunopurified holo-TFIID to this element. TFIID interacts both with Ea TATA-like and Inr sequences, but only the latter is functionally relevant. Unlike TBP, TFIID binds in the absence of TFIIA, indicating a stabilizing role for TBP-associated factors in Ea promoter recognition. Sequence comparison with other mouse and human MHC class II promoters suggests a common mechanism of start site(s) selection for the MHC class II gene family.

Animals↗
PubMed1996

Change in body condition score of Holstein cows as affected by parity and mature equivalent milk yield.

Cows from 25 dairy herds were scored for body condition at 3-mo intervals for over 2 yr to study the pattern of changes during lactation and the effects of parity and milk yield capability of cows on changes in body reserves. Data were recorded for 1395 Holstein cows grouped into three parity classes and five classes of mature equivalent milk yield. The analysis model accounted for nearly 70% of the variation in body condition score. Body reserves decreased during early lactation until about 100 DIM and were restored during mid and late lactation. The pattern of change in body condition score varied among lactations and dairy merit of cows. Depletion and subsequent recovery of body reserves were less intense for primiparous cows than for multiparous cows. Loss of body condition scores was higher and more prolonged for cows of higher dairy merit. The minimum body condition score occurred at 3 mo after calving for the worst yielding cows and at 4 mo after calving for the best yielding cows; the highest yielding cows had twice the loss in body condition as the lowest yielding cows. General equations are presented as a proposed guideline to examine changes in body condition score of Holstein cows of different parities and dairy merit.

Adipose Tissue↗
PubMed1995

CCAAT-box binding protein NF-Y (CBF, CP1) recognizes the minor groove and distorts DNA.

The CCAAT box is one of the most common promoter elements. The evolutionarily conserved heteromeric factor NF-Y binds this sequence with high affinity and specificity. By comparing the methylation interference patterns of different sites, performing electrophoretic mobility shift assays (EMSA) with IC-substituted oligonucleotides and competition experiments with the minor groove binding (MGB) drugs distamicin A, tallimustine and Hoechst 33258 we show that NF-Y makes key minor groove interactions. Circular permutation assays on four CCAAT boxes, MHC Class II Ea, HSP70, epsilon-globin and MSV, indicate that NF-Y is able to distort the double helix by angles of 62-82 degrees, depending on the site used, and suggest that nucleotides flanking the CCAAT pentanucleotide influence the degree of bending.

Base Sequence↗
PubMed1995

Distamycin A and tallimustine inhibit TBP binding and basal in vitro transcription.

The antibiotic distamycin A is a DNA minor groove binding drug (MGB) that recognizes a stretch of at least four ATs. The alkylating benzoyl mustard derivative tallimustine (FCE 24517) has powerful anti-tumor activity. Using the electrophoretic mobility shift assay (EMSA) we determined that both compounds can prevent binding of TBP and, with 10-fold higher concentration, TBP-TFIIA (DA) and TBP-TFIIA-TFIIB (DAB) to a TATA box. Once formed, the DA and DAB complexes are more resistant to MGB challenge. Both drugs can inhibit basal in vitro transcription of a minimal TATA-containing promoter and similar concentrations are necessary for binding and transcriptional inhibition. Tallimustine shows strong selectivity by decreasing only correctly initiated transcripts. Even at high doses (20 microM), however, they cannot disturb a competent pre-initiation complex or Pol II progression. This functional in vitro model will provide a way to investigate the activity of sequence-specific DNA binding drugs with potential anti-viral and anti-tumour activity and to develop novel more selective compounds.

Antineoplastic Agents↗
PubMed1995

Bias and accuracy of single milking testing schemes to estimate daily and lactation milk yield.

This study evaluated the adequacy of an alternate a.m.-p.m. testing scheme for milk yield in comparison with the official test method based on weighing two milkings within 24 h. A total of 88,558 single test day milking weights from 15,670 Italian Friesian cows in 610 herds in the province of Milano (Italy) were collected between September 1991 and October 1992. Ratios were computed for daily milk yield to a.m. and p.m. milking weights (direct yield ratios) and ratios of a.m and p.m. milking weights to daily milk yield (inverse yield ratios). Analysis of variance indicated that the milking interval is the most important source of variation for yield ratios. Factors for estimating daily milk yield from single milking weights adjusted for milking intervals were derived through regression analysis of direct and inverse yield ratios on the length of the milking interval. Daily milk yield was estimated more precisely and accurately when adjustment factors were used than when single milking weights were doubled. The doubling of a.m. and p.m. milking weights overestimated and underestimated (5% on average) daily milk yield, respectively. For 305-d lactation yield, accuracies of these methods were comparable. In conclusion, alternate recording of a.m. and p.m. milking weights led to reliable estimates of milk yield. Effects of the alternate a.m.-p.m. testing scheme on estimates of milk components and genetic evaluations of dams of sires should be investigated.

Animals↗
PubMed1994

Dominant negative analogs of NF-YA.

NF-Y is a highly conserved heteromeric CCAAT-binding transcription factor involved in the function of several promoters. The NF-YA subunit contains a domain of high homology to yeast HAP2, which we show to be necessary and sufficient to mediate interactions with the NF-YB subunit and with DNA. Using protein affinity columns derivatized with amino acid substitution mutants, we further dissect this region into two functionally separable subdomains. The subunit association function resides in a 21-amino acid stretch, which is almost perfectly conserved among different species, while interaction with DNA resides in another short segment. We also show that DNA-binding mutants act as dominant repressors of NF-Y-DNA complex formation and of NF-Y-dependent transcription.

Amino Acid Sequence↗
PubMed1994

Modeling response to slow-releasing somatotropin administered at 3- or 4-week intervals.

The purpose of this study was to develop a time-dependent model to account for the effects of recombinant bST in a slow-release formulation on short-term (between two consecutive injections) and long-term (baseline of the lactation curve) response of milk yield and composition. Observations on milk yield (n = 8234) and on milk composition (n = 1509) of 196 Holstein Friesian cows were recorded over 1 yr of trial. Treated cows were injected with somidobove at 3- or 4-wk intervals. Data were analyzed according to a model that included effect of treatment, parity, interaction, and the random effect of cow; two time-dependent covariables, obtained by the splitting of DIM, were included in the model to account for the effects of bST on short- and long-term responses of milk traits. Cyclical variations of milk yield, protein, and SCC content in the interval between two consecutive injections were detected. Recombinant bST administration also influenced the persistency of milk yield and protein content. Treatment of cows at 3- and 4-wk intervals increased yield by 20.6 and 12.6% over those of untreated cows. Nearly 60% of this increment was due to the short-term effect of bST. Milk composition response to bST was less noticeable.

Animals↗
PubMed1993

The major histocompatibility complex (MHC) Ea promoter: sequences and factors at the initiation site.

We have analysed the function of sequences in the TATA/initiator region of the promoter of Ea, a class II gene of the Major Histocompatibility Complex. We find that the Ea promoter contains an initiator element with a strong influence on transcription. We also find that the Ea promoter does contain a bona fide TATA box, which can be recognized by the TATA binding protein (TBP), and that TBP is required for transcriptional activity. For activity, TBP must be included within a larger TFIID complex, as Ea transcription in a heat-treated extract can be restored by immunopurified TFIID but not by TBP alone. On the other hand, the TATA motif can be eliminated without significantly affecting either the efficiency or the startsites of transcription. This suggests that TBP, even in this TATA-containing promoter, is held in place by other components of the initiation complex, regardless of its affinity for the underlying DNA.

Animals↗
PubMed1993

Studies on the possible biological effects of 50 Hz electric and/or magnetic fields: evaluation of some glycolytic enzymes, glycolytic flux, energy and oxido-reductive potentials in human erythrocytes exposed in vitro to power frequency fields.

An attempt has been made to understand whether 50 Hz electric and magnetic fields (EMFs) are involved in producing bioeffects by exposing human erythrocytes in vitro. The study evaluated some key glycolytic enzymes, glucose consumption, lactate production, energy charge, 2,3-diphosphoglycerate, and reduced glutathione levels, all of which are biochemical parameters significant to erythrocyte function. Cells exposed to individual or superimposed EMFs have not shown any significant difference compared with the controls.

2,3-Diphosphoglycerate↗
PubMed1993

The effects of once or twice daily injections of pFSH on superovulatory response in heifers.

Follicle stimulating hormone (FSH) is a glycoprotein hormone with a short half-life and has to be given twice daily for 3-4 days to induce superovulation in heifers. Since such a regimen is time consuming we compared the ovulatory response and yield of embryos in heifers following superovulation with either once or twice daily injections of pFSH for 4 days during the mid-luteal phase of a synchronized estrous cycle or during a prolonged luteal phase in heifers which had been immunized against prostaglandin F2alpha (PG). In Experiment 1, crossbred heifers (n = 42) previously actively immunized against a PG immunogen were superovulated in a 2 (cyclic or persistent corpus luteum) x 2 (once or twice daily injection) factorial plan. The heifers were superovulated with 75 units pFSH, which was injected subcutaneously once (22.5, 22.5, 15 and 15 units per day) or twice daily (9.3 units per injection) for 4 days. In Experiment 2, cyclic crossbred beef heifers (n = 80) were superovulated using pFSH which was given randomly to heifers once daily subcutaneously (T1) or twice daily intramuscularly (T2) using the same daily dose of 9, 7, 5, and 3 mg per day. Estrus was induced in all heifers in both experiments using 500 mug and 250 mug Cloprostenol 12 hours apart on the third day of pFSH injections. All heifers were inseminated twice with frozen-thawed semen at 12 and 24 hours after the onset of standing estrus or at 56 and 72 hours after the first PG if estrus was not observed. Embryos were recovered at slaughter and graded on a scale of 1 to 5 (1 = excellent, 5 = degenerated). Data were recorded for the number of corpora lutea (CL), large (>/=10 mm) and medium (5-9 mm) follicles, number of embryos recovered and embryo morphology. Data were analyzed by least squares analysis of variance procedures. In Experiment 1, there was no difference in ovulation rate between main effects. Fewer embryos were recovered from heifers with a persistent corpus luteum (pCL) and injected once daily (1.71+/-.75 vs 5.75+/-1.27) than from any other group. Heifers with pCL yielded lower (P < 0.05) numbers of freezable embryos than cyclic animals, regardless of injection regimen. In Experiment 2, T2 heifers had a significantly higher number of CL (16.4+/-1.7 vs 7.7+/-1.7; P = 0.0003), large follicles (4.1+/-0.5 vs 2.8+/-0.5; P = 0.04), medium follicles (6.4+/-0.7 vs 4.4+/-0.7; P = 0.04), embryos recovered (9.6+/-1.1 vs 4.9+/-1.1; P = 0.0025) and freezable embryos (4.7+/-0.7 vs 2.1+/-0.7; P = 0.014) than T1 heifers. It is concluded that a single daily subcutaneous injection of pFSH results in a lower superovulatory response than the twice daily regimen in heifers.

Journal Article↗
PubMed1992

Intron-exon organization of the NF-Y genes. Tissue-specific splicing modifies an activation domain.

NF-Y is a highly conserved transcription factor which recognizes CCAAT motifs in a variety of genes. We report here the genomic organization of the genes encoding both subunits, which gives interesting clues about the functional organization of the proteins. We also report the existence of isoforms of NF-YA which result from differential splicing. These alternative splicing events map within a glutamine-rich activation domain and show a marked cell- and tissue-specific bias.

Amino Acid Sequence↗
PubMed1992

Evolutionary variation of the CCAAT-binding transcription factor NF-Y.

NF-Y is a CCAAT-specific transcription factor thought to be involved in the regulation of a variety of eukaryotic genes. It shows a striking sequence similarity with the yeast factor HAP2/3. In an attempt to trace back its evolutionary history, we succeeded in isolating NF-Y cDNA clones from a plant and from several species of vertebrates. The patterns of sequence conservation delineate potential functional domains: A central, highly conserved, domain likely responsible for DNA-binding and subunit interaction; more evolutionarily flexible flanking regions, in which variability is clustered, individualizing conserved glutamine or acidic amino-acids putatively involved in protein-protein contacts.

Amino Acid Sequence↗
PubMed1992

Monoclonal antibodies to NF-Y define its function in MHC class II and albumin gene transcription.

NF-Y is a sequence-specific DNA-binding protein which, as a heterodimer, recognizes CCAAT motifs in a variety of transcriptional promoters. We have generated a panel of monoclonal and affinity-purified polyclonal antibodies directed against various epitopes of NF-Y. These reagents are highly specific for either of the A or B subunits; we have mapped the epitopes recognized by the monoclonal antibodies to the glutamine-rich activation domain of NF-YA. The antibodies inhibit in vitro transcription from the promoters of the albumin gene and of Ea, a class II gene of the major histocompatibility complex. These data definitively demonstrate the role of NF-Y in regulating the transcription of two tissue-specific genes whose expression patterns do not overlap. Interestingly, the antibodies cannot inhibit a formed pre-initiation complex, but do block reinitiation of subsequent rounds of transcription from the same templates.

Albumins↗