Biomedical subjects

F Baldi

Publications and source records attributed to F Baldi.

At least 73 records · Page 4Linked to original sources

PubMed1997

Differential expression of Rb2/p130 and p107 in normal human tissues and in primary lung cancer.

Two proteins, p107 and pRb2/p130, which are structurally and functionally similar to the product of the retinoblastoma gene (pRb), were cloned by taking advantage of their ability to bind transforming proteins of DNA tumor viruses through a particular region called the "pocket domain." Like pRb, both proteins play a fundamental role in growth control. Using immunocytochemical techniques, we examined a variety of normal human tissues for the expression of pRb2/p130 and p107. Both proteins were expressed ubiquitously, although a different tissue distribution and/or level of expression were found in various organs. Terminally differentiated cells, such as neurons and skeletal muscle, showed high expression levels for Rb2/p130, whereas p107 was expressed at higher levels in other cell types such as epithelia of the breast and prostate. We then examined the expression pattern of Rb2/p130 in 158 specimens of human lung cancer and found an inverse correlation between the histological grading of the tumors, the development of metastasis, and the level of expression of Rb2/p130.

Blood Cells↗

PubMed1996

Small volume isosmotic polyethylene glycol electrolyte balanced solution (PMF-100) in treatment of chronic nonorganic constipation.

The present multicenter double-blind placebo-controlled trial evaluates the therapeutic effectiveness of small-volume daily doses of an isosmotic polyethylene glycol (PEG) electrolyte solution in the treatment of chronic nonorganic constipation. After a complete diagnostic investigation, patients still constipated at the end of a four-week placebo-treatment run-in period were enrolled and randomized to receive either placebo or PEG solution 250 ml twice a day for the following eight weeks. Patients were assessed at four and eight weeks of treatment, and they reported frequency and modality of evacuation, use of laxatives, and relevant symptoms daily on a diary card. Oroanal and segmental large-bowel transit times were assessed with radiopaque markers during the fourth week of the run-in period and the last week of the treatment period. During the study period, dietary fiber and liquids were standardized and laxatives were allowed only after five consecutive days without a bowel movement. Of the 55 patients enrolled, five dropped out, three because of adverse events and two for reasons unrelated to therapy; another two were excluded from the efficacy analysis because of protocol violation. Of the remaining 48 patients (37 women, age 42 +/- 15 years, mean +/- SD), 23 were assigned to placebo and 25 to PEG treatment. In comparison to placebo, PEG solution induced a statistically significant increase in weekly bowel frequency at four weeks and at the end of the study (PEG: 4.8 +/- 2.3 vs placebo: 2.8 +/- 1.6; P < 0.002) and a significant decrease in straining at defecation (P < 0.01), stool consistency (P < 0.02), and use of laxatives (P < 0.03). Oroanal, left colon, and rectal transit times were significantly shortened by PEG treatment. There was no difference between controls and PEG-treated patients as far as abdominal symptoms and side effects were concerned. In conclusion, PEG solution at 250 ml twice a day is effective in increasing bowel frequency, accelerating colorectal transit times, and improving difficult evacuation in patients with chronic nonorganic constipation and is devoid of significant side effects.

Adolescent↗

PubMed1996

Dissolution of Barium from Barite in Sewage Sludges and Cultures of Desulfovibrio desulfuricans.

High concentrations of total barium, ranging from 0.42 to 1.58 mg(middot)g(sup-1) (dry weight) were found in sludges of two sewage treatment plants near Florence, Italy. Barium concentrations in the suspended matter decreased as redox potential values changed from negative to positive. An anoxic sewage sludge sample was aerated, and 30% of the total barium was removed in 24 h. To demonstrate that barium was solubilized from barite by sulfate-reducing bacteria, a strain of Desulfovibrio desulfuricans was used to study the solubilization of barium from barite under laboratory conditions. During cell growth with different concentrations of barite from 0.01 to 0.3 g(middot)liter(sup-1) (the latter is the MIC) as the only source of sulfates in the cultures, the D. desulfuricans strain accumulated barium up to 0.58 (mu)g(middot)mg(sup-1) (dry weight). Three times the quantity of barium was dissolved by bacteria than in the uninoculated medium (control). The unexpectedly low concentration of soluble barium (1.2 mg of Ba(middot)liter(sup-1)) with respect to the quantity expected (109 mg of Ba(middot)liter(sup-1)), calculated on the basis of the free H(inf2)S evolved from the dissimilatory reduction of sulfate from barite, was probably due to the formation of other barium compounds, such as witherite (BaCO(inf3)) and the transient species barium sulfide (BaS). The D. desulfuricans strain, growing on barite, formed visible aggregates. Confocal microscopy analysis showed that aggregates consisted of bacteria and barite. After 3 days of incubation, several autofluorescent crystals surrounded by a dissolution halo were observed. The crystals were identified as BaS by comparison with the commercial compound.

Journal Article↗

PubMed1996

Differential expression of the retinoblastoma gene family members pRb/p105, p107, and pRb2/p130 in lung cancer.

The Rb (retinoblastoma) gene family is composed of three members: the RB gene (one of the best-studied tumor suppressor genes) and two related genes, p107 and pRb2/p130. These three proteins share many structural and functional features and play a fundamental role in growth control. Using immunocytochemical techniques, we evaluated a variety of lung tumor specimens for the expression of this family of proteins and compared protein expression with the histological grading of the tumors and with the expression of the proliferating cell nuclear antigen. These Rb family members displayed distinctive patterns when compared and contrasted using different parameters. The highest percentage of undetectable levels in all of the specimens examined and the tightest inverse correlation (P) with the histological grading and with proliferating cell nuclear antigen expression in the most aggressive tumor types were found for pRb2/p130, which may suggest an important role for this protein in the pathogenesis and progression of lung cancer.

Animals↗

PubMed1995

The RB2/p130 gene product is a nuclear protein whose phosphorylation is cell cycle regulated.

The Rb2/p130 protein has been shown to have a high sequence homology with the retinoblastoma gene product (pRb), one of the most well-characterized tumor suppressor genes, and with pRB-related p107, especially in their conserved pocket domains, which display a primary role in the function of these proteins. In this study, we report on the biochemical and immunocytochemical characterization of the Rb2/p130 protein, using a polyclonal antibody developed against its "spacer" region included in the pocket domain of the whole protein. We show that pRb2/p130 is a phosphoprotein located at the nuclear level and that its phosphorylation pathway can be dramatically reduced by phosphatase treatment. Moreover pRb2/p130 with p107, is one of the major targets of the E1A viral oncoprotein-associated kinase activity, showing a phosphorylation pattern which is modulated during the cell cycle, reaching a peak of activation at the onset of S-phase.

Antibodies, Monoclonal↗

PubMed1995

Non-cardiac chest pain: a real clinical problem.

Non-cardiac chest pain is a frequent clinical problem. Between 10 and 50% of patients with anginal pain who are referred for arteriography are found to have normal coronary arteries. An oesophageal source of non-cardiac chest pain is reported in up to 60% of cases, most of which are attributable to gastro-oesophageal reflux disease. The exclusion of heart disease and the identification of an oesophageal origin of the pain may require an extensive work-up. The outcome in patients with non-cardiac chest pain is influenced by both the underlying diagnosis and the patient's perception of his or her symptom.

Cardiomyopathies↗

PubMed1993

Coal Depyritization by the Thermophilic Archaeon Metallosphaera sedula.

The kinetics of pyrite oxidation by Metallosphaera sedula were investigated with mineral pyrite and two coals with moderate (Pittsburgh no. 8) and high (New Brunswick, Canada) pyritic sulfur content. M. sedula oxidized mineral pyrite at a greater rate than did another thermophile, Acidianus brierleyi, or a mesophile, Thiobacillus ferrooxidans. Maximum rates of coal depyritization were also greater with M. sedula, although the magnitude of biological stimulation above abiotic rates was notably less than with mineral pyrite. Coal depyritization appears to be limited by the oxidation of pyrite with ferric ions and not by the rate of biotic oxidation of ferrous iron, as evidenced by the maintenance of a high ratio of ferric to ferrous iron in solution by M. sedula. Significant precipitation of hydronium jarosite at elevated temperature occurred only with New Brunswick coal.

Journal Article↗

PubMed1993

Methylmercury Resistance in Desulfovibrio desulfuricans Strains in Relation to Methylmercury Degradation.

Two strains of Desulfovibrio desulfuricans, one known to synthesize monomethylmercury from ionic mercury, were grown to determine methylmercury toxicity and for comparison with an anaerobic strain of Clostridium pasteurianum, a H(2) producer, and with the broad-spectrum mercury-resistant Pseudomonas putida strain FB-1, capable of degrading 1 mug of methylmercury to methane and elemental mercury in 2 h. The CH(3)HgCl resistance of D. desulfuricans strains was 10 times that of P. putida FB-1 and 100 times that of C. pasteurianum. The methylmercury resistance of D. desulfuricans was related to the disappearance of methylmercury from cultures by transformation to dimethylmercury, metacinnabar, methane, and traces of ionic mercury. During a 15-day experiment the kinetics of the two volatile compounds dimethylmercury [(CH(3))(2)Hg] and methane were monitored in the liquid by a specific new technique with purge-and-trap gas chromatography in line with Fourier transform infrared spectroscopy and in the headspace by gas chromatography with flame ionization detection. Insoluble metacinnabar (cubic HgS) of biological origin was detected by X-ray diffractometry in the gray precipitate from the insoluble residue of the pellet of a 1-liter culture spiked with 100 mg of CH(3)HgCl. This was compared with a 1-liter culture of D. desulfuricans LS spiked with 100 mg of HgCl(2). In a further experiment, it was demonstrated that insoluble, decomposable, white dimethylmercury sulfide [(CH(3)Hg)(2)S] formed instantly in the reaction of methylmercury with hydrogen sulfide. This organomercurial was extracted with chloroform and identified by gas chromatography in line with mass spectrometry. The D. desulfuricans strains were resistant to high concentrations of methylmercury because they produced insoluble dimethylmercury sulfide, which slowly decomposed under anaerobic conditions to metacinnabar and volatilized to dimethylmercury and methane between pHs 6.2 and 6.5 for high (4.5-g . liter) or low (0.09-g . liter) sulfate contents. Methane was produced from CH(3)HgCl at a lower rate than by the broad-spectrum Hg-resistant P. putida strain FB-1.

Journal Article↗

PubMed1993

Treatment of uncomplicated cases of rhegmatogenous retinal detachment with an expanding gas bubble.

We reviewed 55 consecutive cases of rhegmatogenous retinal detachment treated with pneumatic retinopexy as a primary procedure and followed up for a minimum of 1 year. 40 eyes were phakic, 11 aphakic and 4 pseudophakic. 0.6 ml of sulfur hexafluoride were injected into 42 eyes, while 0.3 ml of perfluoropropane were introduced into 13. Transconjunctival cryotherapy was performed in 51 eyes, while light coagulation was used as retinopexy after the retina was reattached in the remaining 4 cases. Of the 55 eyes undergoing treatment, 46 (83.6%) retinas were reattached with one operation. The benefits, complications and disadvantages of the procedure are reported.

Adolescent↗

PubMed1992

Modulation of chromium(VI) toxicity by organic and inorganic sulfur species in yeasts from industrial wastes.

Two chromium(VI) resistant yeast strains (Candida sp. and Rhodosporidium sp.) were isolated from industrial wastes. Four different yeasts, three from the Industrial Yeast Collection and one of pharmaceutical origin, were also studied in relation to chromate toxicity and its alleviation by sulfur species. The growth of yeasts from industrial wastes was inhibited by 50% by high concentrations of Cr(VI): Candida sp. by 4 mM Cr(VI) and Rhodosporidium sp. by 10 mM Cr(VI) in Sabouraud Broth medium. The other Cr(VI)-sensitive yeasts were inhibited by 0.1 mM Cr(VI). The general mechanism of chromium resistance in Candida sp. and Rhodosporidium sp. was due to reduced uptake of chromium, but not to biological reduction from Cr(VI) to Cr(III). In Cr(VI)-sensitive yeasts, chromium was accumulated as much as 10-fold, as in Saccharomyces cerevisiae. Cr(VI) toxicity in Candida sp. was modulated from Cr(VI)-resistance to Cr(VI)-hypersensitivity depending on the addition of methionine, cysteine, sulfate and djenkolic acid. If Candida sp. was grown in the presence of S-amino acids, especially methionine, it was more resistant than if the sulfur source was sulfate. When sulfate transport was enhanced by addition of djenkolic acid, Candida sp. became hypersensitive. Rhosporidium sp. was always resistant to Cr(VI) because sulfate transport was inefficient and it assimilated sulfur as S-amino acids. Cr(VI)-sensitive yeasts required larger amounts of S-amino acids, especially methionine, to tolerate Cr(VI) toxicity. Cysteine was toxic for C.famata 6016 above 50 microM.

Amino Acids, Sulfur↗

PubMed1992

Leaching of Pyrites of Various Reactivities by Thiobacillus ferrooxidans.

Wide variations were found in the rate of chemical and microbiological leaching of iron from pyritic materials from various sources. Thiobacillus ferrooxidans accelerated leaching of iron from all of the pyritic materials tested in shake flask suspensions at loadings of 0.4% (wt/vol) pulp density. The most chemically reactive pyrites exhibited the fastest bioleaching rates. However, at 2.0% pulp density, a delay in onset of bioleaching occurred with two of the pyrites derived from coal sources. T. ferrooxidans was unable to oxidize the most chemically reactive pyrite at 2.0% pulp density. No inhibition of pyrite oxidation by T. ferrooxidans occurred with mineral pyrite at 2.0% pulp density. Experiments with the most chemically reactive pyrite indicated that the leachates from the material were not inhibitory to iron oxidation by T. ferrooxidans.

Journal Article↗

PubMed1992

Octylonium bromide in the treatment of the irritable bowel syndrome: a clinical-functional study.

We investigated the effect of octylonium bromide on a number of symptoms and functional aspects of the irritable bowel syndrome. Seventy-two patients complaining mainly of abdominal pain were studied in a double-blind trial (octylonium bromide 40 mg tid for 4 weeks or placebo). Clinical parameters were: abdominal pain, bloating and bowel frequency. Sigmoid manometry with simultaneous recording of the thresholds for distension and/or pain upon graded inflation of an endoluminal balloon was performed before and at the end of treatment. In contrast to placebo, octylonium bromide significantly reduced pain and bloating, and significantly increased (p < 0.02) the pain threshold throughout the treatment period. However, comparison with the placebo group failed to show any relevant differences. Neither treatment influenced the frequency of bowel movement. Sigmoid motility during distension was significantly reduced after octylonium bromide (p < 0.05), but it did not change after placebo. In conclusion, octylonium bromide is capable of reducing symptoms and motor reactivity of the sigmoid in patients with irritable bowel syndrome.

Abdominal Pain↗

PubMed1991

[Esophageal and gastric acidity determination: its value and limitations].

Combined esophago-gastric pH measurements has been recently employed to better define gastroesophageal reflux and to simultaneously evaluate esophageal and gastric acidity. We studied 21 patients with esophagitis and 11 controls. Gastric acidity was rather similar in the two groups. A significant difference (p less than 0.05) between controls and patients was found in the postprandial period only. The analysis of the buffering effect of a standardized meal did not show any difference between the two groups. When subdividing the esophagitis patients according to the outcome of medical treatment we could find a more prolonged (p less than 0.05) postcibal recovery phase. Gastric alkalinizations were observed mostly during the night and did not differ in the two groups. As regards gastro-esophageal reflux we evaluated both acid, mixed and alkaline episodes. Acid reflux was the most frequent event, while mixed reflux was less frequently observed and equally distributed in the two groups. As regards alkaline episodes they were absent in controls and occurred very rarely in the patients. In conclusion esophagogastric pH-metry gives us, with a single test, informations about gastric acidity and the characteristics of gastro-esophageal reflux. On the other hand its clinical relevance needs further evaluations.

Esophagitis, Peptic↗

PubMed1991

Ambulatory 24-hour oesophageal pH monitoring in normal subjects: a multicentre study in Italy. G.I.S.M.A.D. GOR Study Group.

A multicentre study was performed in Italy in order to establish normal values for acid gastro-oesophageal reflux. In 73 healthy subjects 24-hour oesophageal pH measurements were carried out under standardized conditions. The hourly number of reflux episodes and oesophageal acid exposure was assessed and analyzed by means of a computerized system. The distribution frequency of both parameters was skewed to the left, thus exhibiting a non-normal pattern. Acid reflux was lowest during the night and highest after meals. The oesophageal acid exposure and the number of reflux episodes were correlated both over 24 hours and in the subsets studied. A good agreement was found with data from previous reports. Our findings should be helpful in establishing a data base for physiological gastro-oesophageal reflux.

Adult↗

PubMed1991

Pathogenesis of irritable bowel syndrome.

Irritable bowel syndrome (IBS) is defined as chronic-recurrent abdominal pain in absence of organic lesions. The crucial pathogenetic point is to establish whether pain is related to enhanced sensitivity of the patient or to an abnormal peripheral stimulus originating from the bowel. We can subdivide the patients with abdominal pain into two main groups: the first comprehends those patients with an abnormal response to a normal stimulus (i.e. an enhanced motor response to a meal) (irritable bowel syndrome) and second those patients who have a normal response to an abnormal stimulus (i.e. alimentary factors, laxatives, bile acids) (irritated bowel syndrome). On the basis of our knowledge we can say that the pathogenesis of IBS is complex and not yet completely defined. The crucial point is represented by our capability to discriminate between the "irritable" and "irritated" colon.

Abdominal Pain↗

PubMed1991

Clinical and functional evaluation of the efficacy of otilonium bromide: a multicenter study in Italy.

Seventy-two patients complaining of abdominal pain were studied in a double blind trial with otilonium bromide (OB) (40 mg tid or placebo). In our patients we performed, before and after the treatment, a clinical evaluation (symptom variations) and functional studies (sigmoid manometry during bowel distension). As regards clinical parameters, otilonium bromide significantly reduced abdominal pain and bloating and significantly increased (p less than 0.02) the pain threshold. However the comparison with the placebo group did not show any difference between the two groups. Sigmoid motility during distension was significantly reduced (p less than 0.05) in OB group, whereas it did not change in the placebo group. We can conclude that, in irritable bowel syndrome (IBS) patients, OB is able to improve symptoms and to reduce stimulated motor activity of the sigmoid.

Abdominal Pain↗

PubMed1990

Chromium(VI)-resistant yeast isolated from a sewage treatment plant receiving tannery wastes.

A Cr(VI)-resistant yeast, designated strain DBVPG 6502, was isolated from a sewage treatment plant receiving wastes from tannery industries in Italy. The strain was tentatively identified as a species of Candida based on morphological and physiological analyses. This strain was highly resistant to Cr(VI) when compared with eight other yeast species, growing at Cr(VI) concentrations of up to 500 micrograms/ml (10 mM). This resistance was constitutive. The Cr(VI)-resistant yeast did not reduce Cr(VI) to Cr(III) species under aerobic conditions. The yeast showed very little accumulation of Cr(VI). Consequently, the mechanism of resistance of the yeast to Cr(VI) appears to involve reduced accumulation of Cr, as has been shown in Cr(VI)-resistant bacteria.

Candida↗

PubMed1990

Long-term treatment of reflux oesophagitis.

Reflux oesophagitis is a chronic recurrent disease with high tendency towards relapse after medical healing. It has been calculated that after 6 months a symptomatic relapse may occur in about 45% of patients, while a recurrence of mucosal lesions ranges between 20 to 70%. The most important adverse factors affecting the likelihood of recurrence are: a) the daytime symptoms at time of healing and b) an impairment of both oesophageal body motility and LOS tonic and phasic activity. The available data show that the maintenance treatment with anti-H2 at standard doses does not affect the spontaneous recurrence of the disease. Better results could be achieved with higher dosage, possibly tailored to the physiopathological characteristics of the patients.

Esophagitis, Peptic↗