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Biomedical subjects

A Baldi

Publications and source records attributed to A Baldi.

At least 73 records · Page 4Linked to original sources
PubMed2001

Histopathological features and modulation of type IV collagen expression induced by Pseudomonas aeruginosa lipopolysaccharide (LPS) and porins on mouse skin.

BACKGROUND: Pseudomonas aeruginosa (P. aeruginosa) is responsible for serious infections in the immunocompromised host. Many skin lesions induced by P. aeruginosa have been described. Few investigations have been performed on the local action of P. aeruginosa components. OBJECTIVES: To shed light on the "in vivo" activity of lipopolysaccharide (LPS) and porins extracted from P. aeruginosa, by verifying their effects after inoculation in mouse skin through the observation of histological changes and immunohistochemical expression of collagen IV. RESULTS: Both substances were able to induce a similar inflammatory process and a characteristic reversible change in collagen IV distribution. Interestingly, a fibroblast increase was observed at 24 h in the skin treated with porins, while it appeared later in the skin treated with LPS. Besides these changes, porins particularly increased collagen edema, together with disgregation of hypodermal structures. Moreover "in vitro", porins were able to stimulate fibloblasts 3T3 to convert 72 kDa type IV collagenase into the activated 62 kDa form and to release the 92 kDa collagenase. CONCLUSION: LPS and porins, released by gram-negative bacteria during cell growth and lysis, interact with the host at target cells, such as keratinocytes, fibroblasts and immunocompetent cells, thus contributing significantly to the pathogenesis of P aeruginosa skin infections.

3T3 Cells↗
PubMed2001

Effects of vitamin E on urokinase-plasminogen activator receptor expression by bovine neutrophils.

OBJECTIVE: To determine the effect of vitamin E supplementation on urokinase-plasminogen activator (u-PA) receptor (u-PAR) expression by neutrophils of dairy cows. ANIMALS: 16 healthy Holstein dairy cows. PROCEDURE: 16 cows were assigned to 1 of 2 experimental groups: control (no vitamin E supplementation) and vitamin E supplementation. Supplementation of vitamin E started 4 weeks prior to and continued up to 4 weeks after parturition and included oral administration of vitamin E at 3,000 U/cow per day; these cows also received 1 injection of vitamin E (5,000 units), 1 week prior to the expected date of parturition. Blood samples were collected, and neutrophils were isolated weekly throughout the experimental period. The following variables were measured: u-PA (mRNA), total cell-associated u-PA activity, membrane-bound u-PA activity, and free unoccupied u-PA binding sites on the cell membrane of neutrophils. RESULTS: Stimulated neutrophils isolated from cows that received vitamin E supplementation had significantly higher u-PA mRNA and total cell-associated and membrane-bound u-PA activity at postpartum week 1, compared with those of stimulated neutrophils isolated from control cows. There were no differences between groups throughout the whole experimental period in u-PA binding sites of neutrophils. CONCLUSIONS AND CLINICAL RELEVANCE: The increased total cell-associated and membrane-bound u-PA activity in neutrophils isolated from cows that received vitamin E may facilitate the ability of neutrophils to extravasate and reach the mammary gland at postpartum week 1. Rapid recruitment of neutrophils is critical for proper defense of the gland.

Animals↗
PubMed2001

Plasminogen activation system in goat milk and its relation with composition and coagulation properties.

The activity of plasmin (PL), plasminogen (PG), and plasminogen activator (PA) and their correlation with goat milk components and milk clotting parameters were investigated. Seven late-lactating Saanen goats were used to provide milk samples that were analyzed for PL, PG, and PA activity (colorimetric assay) fat, protein, noncasein nitrogen, nonprotein nitrogen, casein content, and somatic cell count (SCC). Milk clotting parameters (rennet coagulating time = coagulation time; K20 = firming rate of curd; A30 = curd firmness) were measured with a formagraph. Average milk yield and composition were similar to those previously observed in other studies. Plasmin, PG, and PA activity, expressed as units/ml, were, respectively, 20.04 +/- 0.94, 3.21 +/- 0.04, and 1154 +/- 57.61. Plasminogen activity was surprisingly low compared with other species (bovine, ovine), but it was consistent with the high activity of PA. A negative significant correlation was observed between PL and milk casein content. The correlation coefficients between PL and casein/protein ratio and PA and casein/protein ratio were negative and significant. A positive significant correlation was observed between PL and rennet clotting time and PA and rennet clotting time. Also positive was the correlation between PL and K20 and PA and K20. The plasmin activity was negatively correlated with A30. High plasmin and plasminogen activator activity in goat milk appeared to be negatively related with coagulating properties in late lactation, most probably via degradation of casein due to plasmin activity.

Animals↗
PubMed2001

Solitary muscle metastasis from lung carcinoma.

Recurrence after resection of non-small cell lung carcinoma is generally associated with a poor outcome. Limb muscle metastasis from lung cancer is extremely rare. We present a case of a 71-year-old man who presented with a solitary metastasis to his right lower limb two months after right upper lobectomy for lung cancer (stage: T2N0M0). Twenty-four months after surgical excision and chemotherapy he is alive without signs of neoplastic disease. We believe that a more aggressive approach might be considered for selected patients with solitary extracranial and extra-adrenal metastasis from lung cancer.

Aged↗
PubMed2001

Colorectal carcinomas and PTEN/MMAC1 gene mutations.

PURPOSE: PTEN/MMAC1/TEP1 is a tumor suppressor gene encoding a dual-specificity protein phosphatase with homology to the cytoskeleton proteins, chicken tensin and bovine auxilin. PTEN mutations have been described in several types of human cancer. Recently, mutations at an (A)(6) repeat of PTEN exons 7 and 8 in colorectal cancer (CRC) patients with microsatellite instability have been detected. Moreover, an involvement of the transforming growth factor (TGF)-beta pathway in hereditary colorectal syndromes has been proposed. EXPERIMENTAL DESIGN: In this study, we analyzed the frequency of PTEN gene mutations in 36 CRC patients and 5 colon cancer cell lines. Furthermore, in 16 of 36 patients, microsatellite instability and TGF-beta receptor II analysis was possible. The study was performed by PCR and automated sequencing of the entire coding region of the PTEN gene. RESULTS: About 17% of colon cancer patients and one of five (HSR 320) colon cancer cell lines had mutations. Mutations were detected only among patients with locally advanced or metastatic CRC. PTEN mutations were detected in three of five (60%) patients showing both microsatellite instability and TGF-beta receptor II mutations. These patients presented with advanced or metastatic CRC CONCLUSIONS: Overall, these results show that PTEN alteration together with TGF-beta pathway inactivation could contribute to tumorigenesis and metastatic spread of sporadic and microsatellite unstable CRC.

Animals↗
PubMed2000

Adenosine deaminase alleles and autistic disorder: case-control and family-based association studies.

Adenosine deaminase (ADA) plays a relevant role in purine metabolism, immune responses, and peptidase activity, which may be altered in some autistic patients. Codominant ADA1 and ADA2 alleles code for ADA1 and ADA2 allozymes, the most frequent protein isoforms in the general population. Individuals carrying one copy of the ADA2 allele display 15 to 20% lower catalytic activity compared to ADA1 homozygotes. Recent preliminary data suggest that ADA2 alleles may be more frequent among autistic patients than healthy controls. The present study was undertaken to replicate these findings in a new case-control study, to test for linkage/association using a family-based design, and to characterize ADA2-carrying patients by serotonin blood levels, peptiduria, and head circumference. ADA2 alleles were significantly more frequent in 91 Caucasian autistic patients of Italian descent than in 152 unaffected controls (17.6% vs. 7.9%, P = 0.018), as well as among their fathers. Family-based tests involving these 91 singleton families, as well as 44 additional Caucasian-American trios, did not support significant linkage/association. However, the observed preferential maternal transmission of ADA2 alleles, if replicated, may point toward linkage disequilibrium between the ADA2 polymorphism and an imprinted gene variant located in its vicinity. Racial and ethnic differences in ADA allelic distributions, together with the low frequency of the ADA2 allele, may pose methodological problems to future linkage/association studies. Direct assessments of ADA catalytic activity in autistic individuals and unaffected siblings carrying ADA1/ADA1 vs ADA1/ADA2 genotypes may provide stronger evidence of ADA2 contributions to autistic disorder. Am. J. Med. Genet. (Neuropsychiatr. Genet.) 96:784-790, 2000.

Adenosine Deaminase↗
PubMed2000

Rapid desensitization and slow recovery of the cyclic AMP response mediated by histamine H(2) receptors in the U937 cell line.

The present study focused on the desensitization process of the H(2) receptor in U937 cells and the recovery of the cyclic AMP (cAMP) response. Treatment of U937 leukemic cells with the H(2) histamine receptor agonists (+/-)-N(1)-[3-(3, 4-difluorophenyl)-3-(pyridin-2-yl)propyl]-N(2)-[3-(1H-imidazol-4-yl)p ropyl]guanidine (BU-E-75) and amthamine produced a rapid desensitization characterized by decreased cAMP production (T(1/2) = 20 min). Pretreatment with 10 microM BU-E-75 did not induce modifications in the responses to prostaglandin E(2), isoproterenol, or forskolin. H(2) receptor desensitization was not affected by protein kinase A and C inhibitors, but was reduced drastically by Zn(2+) and heparin, known to act as inhibitors of G protein-coupled receptor kinases. Recovery studies of the cAMP response showed that cAMP levels reached 50% of the initial values within 5 hr. Furthermore, desensitization produced an important decrease in the basal level of this cyclic nucleotide. The minimal value was observed 12 hr later, and corresponded to approximately 1.3% of the initial basal level (7.5 vs 0.1 pmol/10(6) cells). This result could be explained by an increase in phosphodiesterase activity following 10 microM BU-E-75 treatment. When cells were exposed for 2 hr to an H(2) agonist, binding assays showed no modification in the number of H(2) receptors; internalization began just after 8 hr. Although the initial desensitization seems to involve G protein-coupled receptor kinases, results indicate that additional mechanisms of regulation were triggered by the H(2) agonists.

Cimetidine↗
PubMed2000

Lack of association between serotonin transporter gene promoter variants and autistic disorder in two ethnically distinct samples.

Family-based studies performed to date provide conflicting evidence of linkage/association between autistic disorder and either the "short" [Cook et al., 1997: Mol Psychiatry 2:247-250] or the "long" [Klauck et al., 1997: Hum Mol Genet 6:2233-2238] allele of a polymorphic repeat located in the serotonin transporter (5-HTT) gene promoter region, affecting 5-HTT gene expression [Lesch et al., 1996: Science 274:1527-1531]. The present study was designed to assess linkage and linkage disequilibrium in two new ethnically distinct samples of families with primary autistic probands. The 5-HTT promoter repeat was genotyped in 54 singleton families collected in Italy and in 32 singleton and 5 multiplex families collected in the U.S.A., yielding a total sample of 98 trios. Linkage/association between 5-HTT gene promoter alleles and autistic disorder was assessed using the transmission/disequilibrium test (TDT) and the haplotype-based haplotype relative risk (HHRR). Both the Italian and the American samples, either singly or combined, displayed no evidence of linkage/association between 5-HTT gene promoter alleles and autistic disorder. Our findings do not support prominent contributions of 5-HTT gene variants to the pathogenesis of idiopathic infantile autism. Heterogeneity in pathogenetic mechanisms underlying the disease may require that linkage/association studies be targeted toward patient subgroups isolated on the basis of specific biochemical markers, such as serotonin (5-HT) blood levels. Am. J. Med. Genet. (Neuropsychiatr. Genet.) 96:123-127, 2000.

Adolescent↗
PubMed2000

Effects of vitamin E and different energy sources on vitamin E status, milk quality and reproduction in transition cows.

We investigated whether vitamin E supplementation and supplemental energy sources (fat or starch) influenced plasma and milk levels of vitamin E, and reproductive and other parameters in 28 Italian Friesian multiparous dry cows. From 14 days before expected calving to 7 days after, the animals were assigned to either basal diet (containing 1000 IU/day of vitamin E) or an extra 1000 IU/day of vitamin E (total 2000 IU). In addition they received either 0.5 kg/day of corn or 0.2 kg/day of calcium soaps. Plasma samples were collected 4 days before expected calving and 4 days after calving and analysed for alpha-tocopherol and cholesterol. Milk yield as well as the composition, somatic cell count (SCC) and alpha-tocopherol of milk were determined 7 and 14 days after calving. Milk yield and composition were unaffected by treatments. SCC was significantly lower in (SCC Log 4.62 versus Log 5.1, P < 0.01) 2000 IU/day animals than in the 1000 IU/day group. Milk alpha-tocopherol was higher (P < 0.001) in animals receiving 2000 IU/day (1.11 vs. 0.65 microgram/ml, P < 0.01). Plasma alpha-tocopherol in animals receiving 2000 IU/day was also higher (P < 0.001) than in cows receiving 1000 IU/day (4.85 vs. 3.25 micrograms/ml), but was not affected by dietary energy source. Number of services and days to conception were lower (P < 0.01) in the 2000 IU vitamin E supplemented cows. To conclude, dietary vitamin E supplementation to periparturient dairy cows increased plasma and milk vitamin E, decreased SCC in milk, and improved fertility but different energy sources had no effect on any measured variable.

Animals↗
PubMed2000

Deafferentation-induced apoptosis of neurons in thalamic somatosensory nuclei of the newborn rat: critical period and rescue from cell death by peripherally applied neurotrophins.

This study shows that unilateral transection of the infraorbital nerve (ION) in newborn (P0) rats induces apoptosis in the contralateral ventrobasal thalamic (VB) complex, as evidenced by terminal transferase-mediated deoxyuridine triphosphate-biotin nick end labelling (TUNEL) and electron miscroscopy. Double-labelling experiments using retrograde transport of labelled microspheres injected into the barrel cortex, followed by TUNEL staining, show that TUNEL-positive cells are thalamocortical neurons. The number of TUNEL-positive cells had begun to increase by 24 h postlesion, increased further 48 h after nerve section, and decreased to control levels after 120 h. Lesion-induced apoptosis in the VB complex is less pronounced if ION section is performed at P4, and disappears if the lesion is performed at P7. This time course closely matches the critical period of lesion-induced plasticity in the barrel cortex. Nerve growth factor (NGF) or brain-derived neurotrophic factor (BDNF), applied on the ION stump alone or in combination, are able to partially rescue thalamic neurons from apoptosis. Total cell counts in the VB complex of P7 animals that underwent ION section at P0 confirm the rescuing effect of BDNF and NGF. Blockade of axonal transport in the ION mimics the effect of ION section. These data suggest that survival-promoting signals from the periphery, maybe neurotrophins, are required for the survival of higher-order neurons in the somatosensory system during the period of fine-tuning of neuronal connections. We also propose that anterograde transneuronal degeneration in the neonatal rat trigeminal system may represent a new animal model for studying the pathways of programmed cell death in vivo.

Animals↗
PubMed2000

Kinetic behavior of three preparations of alpha-tocopherol after oral administration to postpubertal heifers.

OBJECTIVE: To assess the kinetic behavior of 3 preparations of alpha-tocopherol (vitamin E) after oral administration to heifers. ANIMALS: 8 postpubertal Friesian heifers. PROCEDURE: A single oral bolus of 5,000 U of alpha-tocopherol in oil or encapsulated in liposomes or cyclodextrin was administered to each cow, using a 4 X 4 design with 8 days between treatments. Blood samples for kinetic analyses were obtained at various times for 168 hours after treatment. RESULTS: Mean (+/- SEM) maximal plasma concentrations of alpha-tocopherol were 4.86 +/- 0.49 microg/ml, 5.03 +/- 0.39 microg/ml, and 5.08 +/- 0.56 microg/ml after administration of oil, liposomal, and cyclodextrin preparations, respectively. Plasma concentrations peaked 21 to 34 hours after administration. The disappearance rate constant (Kd) was less after administration of alpha-tocopherol encapsulated in liposomes, compared with the other 2 preparations. Area under the concentration versus time curve was greater after administration of either encapsulated form of alpha-tocopherol, compared with alpha-tocopherol in oil, but these differences were not significant. CONCLUSIONS AND CLINICAL RELEVANCE: The lower Kd determined for alpha-tocopherol encapsulated in liposomes suggests that this formulation may result in longer persistance of the vitamin in plasma than the other 2 preparations. Dietary supplementation with alpha-tocopherol encapsulated in liposomes may enhance plasma availability of this vitamin in cattle and could be useful during periods of increased vitamin E requirements, such as parturition and early stages of life.

Administration, Oral↗
PubMed1999

Manipulation of milk production and quality by use of somatotropin in dairy ruminants other than cow.

The ability of recombinant bovine somatotropin (BST) to enhance milk production is well established in cows and in other dairy ruminants. In dairy ewes, we found increased milk yield (20-30%) following treatment with BST, which did not negatively affect the gross composition or coagulating properties of milk, except in the advanced stage of lactation, when the percentages of milk protein and fat were reduced and the coagulation time was improved (shorter) compared with untreated animals. In dairy goats, administration of BST increased overall milk yield by 14-29%. Our studies and those of others on the Italian river buffalo showed that BST treatment increased milk yield by about 17%, or more, when associated with dietary protected fat, without affecting milk protein content. In general, studies on dairy ruminants show that treatment with BST increases milk production in the short term (immediate postinjection period) and that there is also a medium to long term effect on persistency of lactation. There is evidence that mammary gland involution can be at least partially reversed by BST administration, and this could be due to limitation in the decrease in mammary parenchyma as lactation progresses and/or to modulation of the plasmin-plasminogen system.

Animals↗
PubMed1999

Differential expression of the retinoblastoma gene family members in choroidal melanoma: prognostic significance.

We evaluated 55 samples of choroidal melanoma managed by enucleation. Knowing that the immunohistochemical expression of the retinoblastoma gene family members Rb/p105, p107, and pRb2/p130 was inversely correlated with the degree of malignancy in at least some histological types, we investigated the expression of these three proteins in choroidal melanoma. We focused on the relationship between patient survival and the immunohistochemical detection of the retinoblastoma proteins. No correlation with clinical outcome was found for Rb/p105 and p107. However, we found pRb2/p130 to be an independent prognostic factor correlating positively or directly with patient survival times and indirectly or inversely with the degree of malignancy. Demonstration of the prognostic value of the immunohistochemical expression of pRb2/p130 is of significance, even if additional studies are required to confirm these data and to compare the prognostic value of pRb2/p130 immunodetection to that of other recently proposed markers, such as p53.

Choroid Neoplasms↗
PubMed1999

Relapsing pneumothorax due to Ascaris lumbricoides larvae.

We describe a case of relapsing pneumothorax occurring in a male child aged 11 yrs, resulting from the mechanical inflammatory action of Ascaris lumbricoides larvae localized in the pleuropulmonary tissue. Pulmonary ascariasis should still be considered today in the differential diagnosis of spontaneous pneumothorax occurring in children.

Animals↗
PubMed1998

Expression of a recombinant Fab antibody fragment against cruzipain, the major cysteine proteinase of Trypanosoma cruzi.

Cruzipain, the major proteinase of Trypanosoma cruzi, plays an important role in the biology of this parasite. This study reports the development of a recombinant Fab antibody, using RNA isolated from the anti-Ag163B6 hybridoma against cruzipain. This procedure involves the use of cDNAs obtained with the aid of a specific set of primers complementary to the complete light kappa chain (L kappa) and the first two domains of the IgG1 heavy chain (VH/CH1). These products were subsequently cloned in the pComb3 system, from which the gIII gene had been removed, and expressed in Escherichia coli cells. The recombinant Fab molecule recognized cruzipain by ELISA, in a fashion similar to the original mAb anti-Ag163B6. Nucleotide sequence analysis of the recombinant molecule, together with its immunological recognition by specific anti-mouse IgG (Fab)2, indicated the immunoglobulin nature of the recombinant product. Moreover, both the mAb anti-Ag163B6 and the soluble Fab fragment described here react similarly with the intact parasite surface, as observed in an indirect immunofluorescence assay. In conclusion, our recombinant Fab anti-Ag 163B6 allows the possible use of this molecule for diagnosis, antigen purification, and eventually treatment of Chagas-afflicted individuals.

Animals↗
PubMed1998

Forskolin induces U937 cell line differentiation as a result of a sustained cAMP elevation.

The present study examines the effects of forskolin on U937 cell differentiation. We recently reported that dibutyryl cAMP (dbcAMP), but not cAMP-elevating agents such as histamine, promotes U937 cell differentiation. cAMP production elicited by stimulation of histamine H2 receptors showed a rapid, homologous desensitization, which might explain the dissimilar responses to histamine and dbcAMP. Forskolin induced an increase in cAMP levels in a concentration-dependent manner (EC50=30 microM) for an extended period of at least 24 h. Forskolin but not histamine (up to 100 microM), also inhibited cell growth in a dose-dependent fashion (EC50=22 microM). After 3 days of incubation, 75 microM forskolin induced U937 cell differentiation as judged by an increased rate of reduction of nitrobluetetrazolium (mean+/-S.E.M.: 21.3+/-6.6% in treated cells vs. 3.2+/-1.9% in the control group, P < 0.001) and an augmented chemotactic response to complement 5a (C5a) (33.2+/-5.9% in forskolin-treated vs. 0.34+/-0.12% in control cells, P < 0.01). Furthermore, c-Myc levels decreased following forskolin treatment, while the histamine H2 receptor agonist dimaprit had no effect. We conclude that forskolin induces U937 cell differentiation through a sustained rise in cAMP levels.

Antigens, Neoplasm↗
PubMed1998

Antioxidant Activity of Different Phenolic Fractions Separated from an Italian Red Wine.

Using liquid/liquid extraction, three fractions were obtained from an Italian red wine containing single polyphenolic subfractions: (1) phenolic acids and quercetin-3-glucuronide, (2) catechins and quercetin-3-glucoside, and (3) anthocyanins. Beside the scavenging capacity of the different fractions against hydroxyl and peroxyl radicals, the in vitro inhibition of low density lipoprotein oxidation and platelet aggregation (two main events in the pathogenesis of atherosclerosis) were tested. The antioxidant activity of the fractions has been compared with that of the original red wine before and after dealcoholization. The anthocyanin fraction was the most effective both in scavenging reactive oxygen species and in inhibiting lipoprotein oxidation and platelet aggregation. This higher activity can be explained by both its high concentration in red wine and its antioxidant efficiency, which, at least for peroxyl radical scavenging, was three times as high as that of the other two fractions. Our results suggest that anthocyanins could be the key component in red wine in light of the protection against cardiovascular diseases, although this hypothesis needs in vivo evidence.

Journal Article↗