Showing papers by "University of Siena published in 1992"
TL;DR: The results indicate that a guided tissue regeneration procedure can be used to successfully treat recession and compared favorably with the mucogingival surgery in the treatment of deep recession.
Abstract: A surgical technique involving membranes was used to treat localized human buccal recessions 3 mm to 8 mm. The results on 25 patients (test group) were evaluated 18 months postoperatively and compared with the results obtained in 25 other patients (control group) having undergone mucogingival surgery. In the test group, a trapezoidal flap with a large base was raised beyond the mucogingival junction. The exposed root surface was scaled thoroughly to a concave shape. A membrane was bent and adapted onto the concave root surface. The flap was sutured far coronally and the membrane removed one month later. The control patients underwent a 2-step procedure, consisting of a free gingival graft and a coronally positioned flap. The amount of root coverage obtained was similar in the 2 groups (test = 72.73%; control = 70.87%), although the clinical attachment gain (test = 5.12 mm; control = 3.56 mm) and pocket variation (test = 1 mm reduction; control = 0.06 mm increase) differed significantly (P < 0.001). The keratinized tissue width was greater in the control group. The regression analysis showed that the amount of covered root surface after treatment was in strict correlation with the depth of the original recession in the test group, while no correlation was found in the control group. The expected root coverage was greater in the test group when the recession was greater than 4.98 mm, while it was greater in the control group when the recession was less than 4.98 mm. These results indicate that a guided tissue regeneration procedure can be used to successfully treat recession. The membrane procedure compared favorably with the mucogingival surgery in the treatment of deep recession.
261 citations
TL;DR: This chapter focuses on the cytoskeleton of the vegetative cytoplasm of pollen grains and pollen tubes, which is involved in numerous intracellular processes, such as organelle movement, organization of the cy toplasm, endocytosis and exocyTosis, cytomorphogenesis, meiotic and mitotic division, and cell wall deposition.
Abstract: Publisher Summary The pollen grain and the pollen tube fulfill important functions in the sexual reproduction of higher plants. The pollen grain is concerned with conveying the two sperm cells or their progenitor, the generative cell, to the female gametophyte. The pollen tube serves as a guide and a pathway for the sperm cells on their course to the embryo sac so that they can complete double fertilization. This chapter focuses on the cytoskeleton of the vegetative cytoplasm of pollen grains and pollen tubes. The cytoskeleton is involved in numerous intracellular processes, such as organelle movement, organization of the cytoplasm, endocytosis and exocytosis, cytomorphogenesis, meiotic and mitotic division, and cell wall deposition. The distribution of calcium in pollen tubes is discussed in relationship to pollen tube growth, intracellular movement, and the activity of the cytoskeleton. The movements of the organelles and nuclei inside the pollen grain and the pollen tube are also described.
195 citations
TL;DR: Mouse erythrocytes were incubated with oxidizing agents and a rapid release of iron in a desferrioxamine-chelatable form was seen, suggesting a role for GSH in preventing iron release when oxidative stress is imposed by the oxidants.
Abstract: Mouse erythrocytes were incubated with oxidizing agents, phenylhydrazine, divicine and isouramil. With all the oxidants a rapid release of iron in a desferrioxamine (DFO)-chelatable form was seen and it was accompanied by methaemoglobin formation. If the erythrocytes were depleted of GSH by a short preincubation with diethyl maleate, the release of iron was accompanied by lipid peroxidation and, subsequently, haemolysis. GSH depletion by itself did not induce iron release, methaemoglobin formation, lipid peroxidation or haemolysis. Rather, the fate of the cell in which iron is released depended on the intracellular availability of GSH. In addition, iron release was higher in depleted cells than in native ones, suggesting a role for GSH in preventing iron release when oxidative stress is imposed by the oxidants. Iron release preceded lipid peroxidation. The latter was prevented when the erythrocytes were preloaded with DFO in such a way (preincubation with 10 mM-DFO) that the intracellular concentration was equivalent to that of the released iron, but not when the intracellular DFO was lower (preincubation with 0.1 mM-DFO). Extracellular DFO did not affect lipid peroxidation and haemolysis, suggesting again that the observed events occur intracellularly (intracellular chelation of released iron). The relevance of iron release from iron complexes in the mechanisms of cellular damage induced by oxidative stress is discussed.
174 citations
TL;DR: Results demonstrate the possibility of treating human buccal recessions by means of a guided tissue regeneration procedure, with predictable recession reduction and attachment gain, and a minimal amount of keratinized tissue was needed.
Abstract: A guided tissue regeneration procedure was used to treat human buccal recessions, 3 to 7 mm deep, in 12 patients. No procedure for increasing the width of keratinized tissue was performed prior to treatment. A thick bipedicled flap was raised with a semilunar incision in the alveolar mucosa and a marginal incision was extended to the adjacent papilla. The root surface was made concave by curets and burs to create space for regeneration. The membrane was fixed to the cemento-enamel junction and covered by the flap which consisted of the residual gingiva and of alveolar mucosa. The membranes were removed 4 weeks after placement. The patients were recalled 6 months after the reentry procedure. The average reduction in recession was 2.50 mm (P less than 0.01) and the average attachment gain was 2.84 (P less than 0.01). Pocket depth was slightly reduced (0.33 mm), although the degree of reduction was not of statistical significance. The width of keratinized tissue increased slightly (0.83 mm). These results demonstrate the possibility of treating human buccal recessions by means of a guided tissue regeneration procedure, with predictable recession reduction and attachment gain. A minimal amount of keratinized tissue was needed.
157 citations
144 citations
Journal Article•
TL;DR: It is suggested that L-lysine can both enhance intestinal Ca absorption and improve the renal conservation of the absorbed Ca, which may contribute to a positive Ca balance, thus suggesting a potential usefulness of L- Elysine supplements for both preventive and therapeutic interventions in osteoporosis.
132 citations
TL;DR: The M6-E7 fusion protein expressed on the S. gordonii surface was shown to be immunogenic in mice and is the first step in the construction of recombinant live vaccines in which nonpathogenic streptococci as well as other gram-positive bacteria may be used as vectors to deliver heterologous antigens to the immune system.
Abstract: We have developed a system in which a foreign antigen replaces nearly all of the surface-exposed region of the fibrillar M protein from Streptococcus pyogenes and is fused to the C-terminal attachment motif of the M molecule. The fusion protein is thus expressed on the surface of Streptococcus gordonii, a commensal organism of the oral cavity. The antigen chosen to be expressed within the context of the M6 molecule was the E7 protein (98 amino acids) of human papillomavirus type 16. Stable recombinant streptococci were obtained by integrating genetic constructs into the chromosome, exploiting in vivo homologous recombination. The M6-E7 fusion protein expressed on the S. gordonii surface was shown to be immunogenic in mice. This is the first step in the construction of recombinant live vaccines in which nonpathogenic streptococci as well as other gram-positive bacteria may be used as vectors to deliver heterologous antigens to the immune system.
132 citations
Journal Article•
TL;DR: The etched porcelain laminate veneer is a new conservative treatment that offers a solution to fractured, discolored, and worn anterior teeth and may offer guidance in the preparation of laminated veneers.
Abstract: The etched porcelain laminate veneer is a new conservative treatment that offers a solution to fractured, discolored, and worn anterior teeth. Preparation of enamel should be 0.5 mm to give minimal porcelain thickness and to avoid an overcontoured restoration. At the same time, dentinal exposure is contraindicated, because resin bonds better with enamel than with dentin. One hundred fourteen extracted teeth were measured at the gingival, middle, and incisal thirds. The resulting data reported on labial enamel thickness of anterior teeth may offer guidance in the preparation of laminate veneers.
122 citations
TL;DR: Mercury levels were very high, especially in the liver where they reached peaks of 4400 ppm (dry weight) in the striped dolphin and 13,150 ppm in the bottle-nosed dolphin and the toxicological significance of the selenium-mercury interaction is discussed.
103 citations
TL;DR: A new method of collecting skin and hypodermic biopsies in the Fin whale and Striped dolphin in order to analyse Mixed Function Oxidase (MFO) activity and organochlorine contents is described and shows marked differences between the two species.
93 citations
TL;DR: This chapter focuses on the organization, composition, and function of the generative cell and sperm cytoskeleton, which consists of heterodimers of α - and β -tubulin, which share sequence homology at the DNA and protein levels with counterparts in animals.
Abstract: Publisher Summary This chapter focuses on the organization, composition, and function of the generative cell and sperm cytoskeleton. Microtubule (MT) organization in generative and sperm cells (GSP) contrasts sharply with that in the surrounding vegetative cytoplasm. MT is composed of heterodimers of α - and β -tubulin, which share sequence homology at the DNA and protein levels with counterparts in animals. Vegetative MTs in hydrated pollen grains and pollen tubes do not occur in similar thick bundles but instead comprise much thinner elements organized in various patterns. In pollen tubes MTs are arranged primarily in helical to longitudinal arrays in the outer cortex. The cortical elements consist of single MTs or planar groups that are cross-bridged to each other and to the plasma membrane. The MT bundles in GSP are also unlike somatic cell arrays. While cortical MTs are linked to the plasma membrane and associate with each other in somatic cells, the kind of large, flexuous bundles that ramify through the cytoplasm of GSP are not observed. Instead, the MTs are largely limited to a single layer next to the plasma membrane.
TL;DR: It is suggested that BCAA administration before exercise affects the response of some anabolic hormones, mainly HGH and T.
Abstract: It was the aim of the present experiment to detect possible effects of branched-chain amino acids (BCAA) on the endocrine response to 1 h of continuous running. Blood samples were collected from 14 long-distance runners (age 24–42 years) in two different trials performed at 1-week intervals. In both trials (E and P) blood samples were collected at the following times: 9 a.m. (basal values sample), 10.30 a.m. (sample 90), 11.30 a.m. (sample 150), 12.30 p.m. (sample 210); the athletes performed 1 h of running at a constant predetermined speed between samples 90 and 150. Following the basal sample a mixture containing BCAA (E trial), or not containing BCAA (P trial) was ingested. In both trials no hormone basal concentrations, except insulin, were changed before exercise. In P trial, following exercise (sample 150), human growth hormone (HGH), prolactin (PRL), adrenocorticotropic hormone (ACTH) and cortisol (C) increased, while testosterone (T) decreased. In sample 210, after 1 h of rest, while ACTH, PRL and HGH had recovered to basal concentrations, C remained elevated and T displayed a further decrease. In the E trial a similar pattern of change was observed in sample 150 for HGH, PRL, ACTH and C; in sample 210 HGH and PRL displayed significantly lower values than in the corresponding P trial samples. The T was not modified by the running exercise and increased during the recovery period. It is, therefore, suggested that BCAA administration before exercise affects the response of some anabolic hormones, mainly HGH and T.
TL;DR: The monoclonal antibodies MAC 207 and JIM 8, recognizing arabinogalactan epitopes, were used to localize the corresponding antigenic sites in pollen tubes of Nicotiana tabacum L. grown in vitro or semi in vivo.
Abstract: The monoclonal antibodies MAC 207 and JIM 8, recognizing arabinogalactan epitopes, were used to localize the corresponding antigenic sites in pollen tubes of Nicotiana tabacum L. grown in vitro or semi in vivo. The analysis of the immunofluorescence labelling was performed by means of confocal laser scanning microscopy. Most pollen tubes were labelled along their length, with the exception of the tip region, in a ring-like pattern with remarkable periodicity. The diameter of the rings was approx. 12 μm and the distance between two rings was about 6 μm. No labelling of the cytoplasm, the vegetative nucleus or the generative cell was observed. The presence of labelling in the non-apical tube wall after pectinase and cellulase digestion indicates that the epitopes for MAC 207 and JIM 8 are located in the inner callosic sheath of the pollen-tube wall.
TL;DR: Polychlorinated dibenzodioxins are a group of xenobiotics of extreme environmental interest, by virtue of their high toxic potential, coupled with high bioaffinity and resistance to degradation.
Abstract: Polychlorinated dibenzodioxins (PCDDs) are a group of xenobiotics of extreme environmental interest, by virtue of their high toxic potential, coupled with high bioaffinity and resistance to degradation. One in particular (2,3,7,8tetrachloro dibenzo-p-dioxin, 2,3,7,8-TCDD), is probably the most poisonous substance ever introduced into the environment. PCDDs are not intentionally produced, but mainly arise from combustion processes and certain industrial activities; all the sources of these substances are not yet completely known (Hutzinger and Fiedler 1989). However, loads to the environment are certainly significant as PCDD residues may be found in many different environmental matrices (Jones and Bennet 1989).
TL;DR: A random pseudo-polynomial algorithm for the problem of finding a base of specified value in a weighted represented matroid, subject to parity conditions is presented and a specialized version of the algorithm suitable for finding a bases in the intersection of two matroids is described.
TL;DR: Proplastids of both tapetal cells and microsporocytes were present early in anther development and were present in both vegetative and generative cells, while plastids were absent from sperm cells.
TL;DR: These strains both expressed M6 protein on the surface and secreted different amounts of the molecule, since in each case the protein was produced after a transcriptional fusion of emm-6.1 with a different chromosomal promoter.
TL;DR: 200 IU intranasal sCT administered on alternate days is adequate to stop the fast bone loss occurring early after the menopause in women with high bone turnover rates and represents an important addition to the available pharmacologic spectrum for the prevention and treatment of postmenopausal osteoporosis.
Abstract: In order to devise a convenient and effective therapeutic regimen of intranasal salmon calcitonin (sCT) for the treatment of early postmenopausal bone loss, we studied the effects of a 1-year course of sCT nasal spray on vertebral mineral content (VMC), assessed by dual photon densitometry, and bone turnover in 21 early postmenopausal osteoporotic women. Subjects enrolled in the study had a value above the normal average of at least one index of bone turnover: whole body retention (WBR) of 99mTc-methylene-dichloro-bisphosphonate (99mTc-MDP), serum bone gla protein (BGP), urinary hydroxyproline/creatinine excretion (HOP/Cr). After baseline evaluation, patients were randomized for treatment with either sCT (200 IU every other day) or placebo. Treatment with sCT significantly increased VMC by 2.7 +/- 0.9% at 6 months, and 3.3 +/- 0.8% at 1 year, whereas a progressive decline was observed in the placebo group (-2.6 +/- 0.5%, and -3.5 +/- 0.5% after 6 and 12 months, respectively). These changes were associated with a progressive and significant reduction of all parameters of bone turnover in the sCT-treated patients, whereas no changes were detected in the control group during the study period. The differences between the two groups were significant after 1 year for VMC, BGP, and WBR (P less than 0.05, one-way analysis of variance). Thus, 200 IU intranasal sCT administered on alternate days is adequate to stop the fast bone loss occurring early after the menopause in women with high bone turnover rates. This therapeutical modality represents an important addition to the available pharmacologic spectrum for the prevention and treatment of postmenopausal osteoporosis.
TL;DR: It is demonstrated that low-threshold cutaneous afferents from trigeminal and limb nerves exert powerful control on trigemino-facial reflex pathways, probably via a common neural substrate, in addition to any post-synaptic mechanism which might be operating.
Abstract: Changes in the size of the test components (R1 and R2) of the trigemino-facial reflex were studied after electrical subliminal conditioning stimulation were applied to the trigeminal, median and sural nerves. After conditioning activation of the trigeminal nerve (below the reflex threshold), the early R1 reflex component showed phasic facilitation, peaking at about 50 ms of interstimulus delay, followed by a long-lasting inhibition recovering at 300-400 ms. The same conditioning stimulation resulted in a monotonic inhibition of the late R2, starting at 15-20 ms, with a maximum at 100-150 ms and lasting 300-400 ms. Intensity threshold for both the R1 and R2 changes ranged from 0.90 to 0.95 times the perception threshold. A similar longlasting inhibition of the R2 reflex response was also seen after conditioning stimulation applied to low-threshold cutaneous afferents of the median and sural nerves. The minimum effective conditioning-test interval was 25-30 ms and 40-45 ms respectively and lasted 600-700 ms. By contrast the early R1 reflex response exhibited a slight long-lasting facilitation with a time course similar to that of the R2 inhibition. The threshold intensity to obtain facilitation of the R1 and inhibition of the R2 test responses after conditioning volley in the median and sural nerves was similar and ranged from 0.9 to 1.2 times the perception threshold. These results demonstrate that low-threshold cutaneous afferents from trigeminal and limb nerves exert powerful control on trigeminal reflex pathways, probably via a common neural substrate. There is evidence that, in addition to any post-synaptic mechanism which might be operating, presynaptic control is a primary factor contributing to these changes.
TL;DR: In this paper, the antimicrobial properties of 2,4-diamino-6-(3,4,5-trimethoxybenzyl)pyrimidine (isotrimethoprim) and some related derivatives are reported.
TL;DR: Interleukin-2 promoter activity in the presence of ras oncoprotein was inhibited by H7, a potent inhibitor of protein kinase C, but not by HA1004, an inhibitor of cyclic nucleotide-dependent kinase, suggesting that protein Kinase C mediates the ras effect.
TL;DR: Two chromium(VI) resistant yeast strains were isolated from industrial wastes and 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.
Abstract: 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.
TL;DR: Data and a literature review of the intermediate radiosensitivity AT cases show that radioresistant DNA synthesis, cellular radiosensitivity, and the clinical hallmarks behave independently.
Abstract: We identified a subgroup of ataxia-telangiectasia (AT) patients (2 sibs and 1 unrelated case) characterized by typical clinical manifestations of the disease and cellular radiosensitivity intermediate between classical AT and normal subjects. Our data and a literature review of the intermediate radiosensitivity AT cases show that radioresistant DNA synthesis, cellular radiosensitivity (measured in terms of survival and chromosome breakage), and the clinical hallmarks behave independently. This raises a number of interesting questions about the correlation between radiobiological and clinical features, and about the nature of the AT gene(s).
TL;DR: It appears that the treatment may activate the host's immune system by inducing the production of immunoactive cytokines and it may now be possible to rationalize the procedure, improve the regimen and assess the outcome.
TL;DR: Light-scattering measurements of osmotically induced changes in the size of rat liver microsomal vesicles pre-equilibrated in a low-osmolality buffer revealed the saturation of the glucose 6-phosphate permeation system by extravesicular concentrations of glucose 7- phosphate higher than 20-30 mM.
Abstract: Light-scattering measurements of osmotically induced changes in the size of rat liver microsomal vesicles pre-equilibrated in a low-osmolality buffer revealed the following. (1) The increase in extravesicular osmolality by addition of glucose 6-phosphate or mannose 6-phosphate (25 mM each) caused a rapid shrinking of microsomal vesicles. After shrinkage, a rapid swelling phase (t1/2 approx. 22 s) was present with glucose 6-phosphate but absent with mannose 6-phosphate, indicating that the former had entered microsomal vesicles, but the latter had not. (2) Almost identical results were obtained in the absence of any glucose 6-phosphate hydrolysis, i.e. with microsomes pre-treated with 100 microM-vanadate. (3) The anion-channel blocker 4,4'-di-isothiocyanostilbene-2,2'-disulphonic acid (DIDS) suppressed the glucose 6-phosphate-induced swelling phase. (4) The swelling phase was more prolonged as the glucose 6-phosphate concentration increased (t1/2 = 16 +/- 3, 22 +/- 3 and 35 +/- 4 s with 25 mM, 37.5 mM- and 50 mM-glucose 6-phosphate respectively). The behaviour of glucose-6-phosphatase activity of intact and disrupted microsomes measured in the presence of high concentrations (less than 30 mM) of substrate also indicated the saturation of the glucose 6-phosphate permeation system by extravesicular concentrations of glucose 6-phosphate higher than 20-30 mM. Additional experiments showed that vanadate-treated microsomes pre-equilibrated with 0.1 mM- and 1.0 mM-glucose 6-phosphate (and [1-14C]glucose 6-phosphate as a tracer) rapidly (t1/2 less than 20 s) released [1-14C]glucose 6-phosphate when diluted in a glucose 6-phosphate-free medium. The efflux of [1-14C]glucose 6-phosphate was largely prevented by DIDS, allowing an evaluation of the intravesicular space of glucose 6-phosphate of approx. 1.0 microliter/mg of microsomal protein.
TL;DR: In the general context of ideals in universal algebras, this paper studied varietal properties connected with ideals that are equivalent both to Mal'cev conditions and congruence properties such as 0-regularity, O-permutability, etc.
Abstract: In the general context of ideals in universal algebras, we study varietal properties connected with ideals that are equivalent both to Mal'cev conditions and congruence properties such as 0-regularity, O-permutability, etc.
TL;DR: The biochemical similarities observed between the above-mentioned enzymes and the immunolocalization findings strongly support the idea that human eosinophils and neutrophils contain the same enzyme activity.
TL;DR: The experimental results indicate that the nondestructive biomarker BChE can give an early qualitative and semi-quantitative warning of the toxic effects of organophosphate and carbamate insecticides in birds.
Abstract: With the aim of proposing a nondestructive biomarker for monitoring the toxicological risk to birds of exposure to the organophosphorus insecticide azamethiphos and the carbamate insecticide methomyl, laboratory studies were performed on serum “B” esterases in Japanese quail (Coturnix coturnix japonica). The birds received two single dose treatments of each compound (azamethiphos and methomyl), i.e., 50 mg/kg and 250 mg/kg respectively. In the first treatment, serum butyrylcholinesterase (BChE) and carboxylesterase (CbE) were drastically inhibited in the azamethiphos-treated group, 24 h after the dose. No inhibition was detected for BChE and CbE activities in the methomyl-treated group, 24 h after the dose. In the second treatment, the birds died or were sacrified 3 h after the dose. Serum BChE and brain acetylcholinesterase (AChE) were strongly inhibited after treatment with both insecticides. Serum CbE, hepatic microsomal CbE and 7-ethoxyresorufin dealkylation activities were also inhibited. A statistically significant correlation between serum BChE and brain AChE was found at lethal and sublethal doses of these xenobiotics. The experimental results indicate that the nondestructive biomarker BChE can give an early qualitative and semi-quantitative warning of the toxic effects of organophosphate and carbamate insecticides in birds.
TL;DR: MRI can be considered as a useful tool to differentiate optic neuritis together with visual and brainstem auditory evoked potentials in patients with different clinical stages of Leber's disease.
Abstract: The authors describe magnetic resonance imaging (MRI) findings in 15 subjects with different clinical stages of Leber’s disease. A few and no characteristic abnormalities of the optic nerve signal wer
TL;DR: The key for the strong inhibitory properties of L-benzylsuccinate can be found in its ability both to co-ordinate the zinc and to form a short carboxyl-carboxylate-type hydrogen bond (2.5 A) with Glu270.