Minimally Invasive Laminate Veneers: Clinical Aspects in Treatment Planning and Cementation Procedures.

When a definitive aesthetic treatment is determined, it is crucial to grant the patient's wish with the necessary dental treatment. Thus, conservative treatments that are the solution to aesthetic problems involving morphologic modifications and provide the result that the patient expects should always be the first therapeutic option. In this context, ceramic laminate veneers, also known as "contact lens," are capable of providing an extremely faithful reproduction of the natural teeth with great color stability and periodontal biocompatibility. Minimal or no preparation veneers are heavily advertised as the answer to our patients' cosmetic needs, which they can be if they are used correctly in the appropriate case. This report is about ultraconservative restorations to achieve functional and aesthetic rehabilitation through treatment planning. Thus, clinicians should be aware that the preparation for laminate veneers remains within enamel, to ensure the bond strength and avoid or minimize the occurrence of postoperative sensitivity.

A role for ethylene in low-oxygen signaling in rice roots.

Inhibitors of action and synthesis of ethylene (Ag(+), norbornadien, Co(2+)) were able to reduce the level of gamma-aminobutyric acid (Gaba) in rice roots during the development of an anaerobic environment. The inhibitory effect was reversed by the addition of the G protein activator 5'-guanylylimidodiphosphate. Gaba accumulation was modulated by the presence of CO(2) (inhibitor of ethylene action and synthesis) and stimulated by 2-chloroethylphosphonic acid (ethefon). These findings are consistent with a role of ethylene during a low-oxygen stress.

Anaerobic accumulation of amino acids in rice roots: role of the glutamine synthetase/glutamate synthase cycle.

Accumulation of amino acids was studied in rice roots of 3-day-old seedlings subjected for 48h to anaerobic conditions. Alanine and Gaba were the main amino acids accumulated under anoxia. Their synthesis was strongly inhibited by MSX and AZA, inhibitors of glutamine synthetase and glutamate synthase. These activities increased after 8h of anaerobic treatment and, by immunoprecipitation of 35S-labeled proteins, it was shown that glutamine synthetase and ferredoxin-dependent glutamate synthase were synthesized during the treatment. These findings indicate that the glutamine synthetase/glutamate synthase cycle play an important role in anaerobic amino acid accumulation.

Evidence for the involvement of phospholipase C in the anaerobic signal transduction.

Pre-treatment of rice roots for 2 h in aerobic conditions with two phospholipase C (PLC) antagonists, neomycin and compound 48/80 (C48/80), inhibited accumulation of gamma-aminobutyric acid and increased the loss of K+ in the medium during 3 h of anoxia. The presence of Ca2+ and A23187 (Ca2+ ionophore) nullified the effect of PLC inhibitors. Pre-treatment of rice roots with neomycin and C48/80 abolished the anaerobic increase in the concentration of the PLC product inositol 1,4,5-triphosphate. Stimulation of the anaerobic signal transduction pathway with aluminium fluoride (G protein activator) was attenuated by PLC inhibitors. These findings are consistent with the participation of PLC in the anaerobic response.

Incorporation of nitrate nitrogen into amino acids during the anaerobic germination of rice.

Incorporation of(15)NO3-into amino acids was studied during the anaerobic germination of rice seeds. In treated coleoptiles, the label was incorporated into glutamine, glutamate, alanine,γ-aminobutyric acid (Gaba), arginine, aspartate and methionine. These findings are consistent with a primary incorporation of nitrate nitrogen into glutamine, glutamate and aspartate, and their further conversion to alanine, Gaba, arginine and methionine.

Expression of the Enzymes of Nitrate Reduction during the Anaerobic Germination of Rice.

During the anaerobic germination of rice (Oryza sativa L.), nitrate is translocated from the caryopsis and assimilated into the coleoptile (R. Reggiani, M. Mattana, N. Aurisano, A. Bertani [1993] Plant Cell Physiol 34: 379-383). Using antibodies against nitrate and nitrite reductases, proteins with the expected molecular mass were recognized by western blot analysis in extracts from 8-d-old rice coleoptiles. Both enzymes are de novo synthesized in 6- to 8-d-old seedlings, as shown by immunoprecipitation of radiolabeled proteins from young plants grown in the presence of [35S]methio-nine. The anaerobic synthesis of both enzymes was enhanced by the addition of 5 mM KNO3. The effect of exogenous nitrate on the expression of the corresponding genes in anaerobic rice coleoptiles was revealed by the analysis of their transcripts. The importance of the expression of these enzymes during the anaerobic development of rice seedlings is discussed.

Left ventricular filling pattern and pulmonary wedge pressure are closely related in patients with recent anterior myocardial infarction and left ventricular dysfunction.

To determine whether mitral flow velocity can be used to estimate mean pulmonary wedge pressure (PWP) in patients with left ventricular dysfunction, 50 patients with recent Q-wave anterior infarction and a reduced ejection fraction (less than 40%) underwent simultaneous pulsed-wave Doppler measurements of mitral flow and right heart catheterization. Doppler tracings and PWP were recorded at rest, after passive leg lifting (45 degrees) and (in 15 patients with increased PWP) after 5 mg sublingual ISDN. Significant correlations were found between the ratio of peak early to peak late diastolic velocity (E/A) and PWP (r = 0.83). Early diastolic deceleration and the ratio of the time velocity integral of atrial contribution to the total time velocity integral were also correlated to PWP (r = 0.80 and r = 0.79 (respectively). The E/A ratio was less than 1 in 25 patients and more than 1 in the remaining 25. An E/A ratio of at least 1 predicted a PWP of more than 20 mmHg with a sensitivity of 100% and a specificity of 86%. In all five patients, in whom the PWP was less than 20 mmHg at baseline and became greater with leg lifting, the E/A ratio changed from less than 1 to more than 1. After ISDN, changes in E/A ratio from more than 1 to less than 1 identified all 12 patients with a PWP falling below 20 mmHg. In conclusion, patients with recent Q-wave anterior infarction and a reduced ejection fraction mitral flow velocity-derived variables correlate with PWP representing a reliable index for the diagnosis of markedly increased PWP.(ABSTRACT TRUNCATED AT 250 WORDS)

Polyamines in Rice Seedlings under Oxygen-Deficit Stress.

Incubation of 3-d-old seedlings of Oryza sativa L. cv Arborio under anaerobic conditions, leads to a large increase in the titer of free putrescine while aerobic incubation causes a slight decrease. After 2 days, the putrescine level is about 2.5 times greater without oxygen than in air. The rice coleoptile also accumulates a large amount of bound putrescine and, to a lesser extent, spermidine and spermine (mainly as acid-soluble conjugates). Accumulation of conjugates in the roots is severely inhibited by the anaerobic treatment. Feeding experiments with labeled amino acids showed that anoxia stimulates the release of (14)CO(2) from tissues fed with [(14)C]arginine and that arginine is the precursor in putrescine biosynthesis. After 2 d of anoxia, the activity of arginine decarboxylase was 42% and 89% greater in coleoptile and root, respectively, than in the aerobic condition. The causes of the differences in polyamine metabolism in anoxic coleoptiles and roots are discussed.

An investigation into the interaction between nitrogen nutrition, photosynthesis and photorespiration.

Photosynthetic CO2 assimilation, photorespiration and levels of glycollate oxidase and ribulose bisphosphate (RuBP) carboxylase were measured in barley, wheat and maize plants grown on media containing nitrate or ammonium or in plants transferred from nitrate to ammonium. The CO2 compensation point and photorespiratory CO2 release were not altered by the nitrogen growth regime nor by transfer from nitrate to ammonium. In barley and wheat plants grown on ammonium the levels of glycollate oxidase and RuBP carboxylase per unit leaf area were higher than in nitrate grown material. These differences were not evident when the results were expressed on a protein or chlorophyll basis. The ratio of glycollate oxidase activity to RuBP carboxylase activity was not altered by the nitrogen regime.

Mucronate, Mc, a dominant gene of maize which interacts with opaque-2 to suppress zein synthesis.

This paper describes a new dominant mutation of maize, Mc, which interferes in the endosperm with the synthesis of storage proteins. The mutant is characterized by an opaque phenotype; it reduces the deposition of zein and it increases the level of methionine. The mutation is specifically related to storage protein synthesis since soluble and insoluble carbohydrates are present at normal levels. The main interest of this mutant lies in its synergistic interaction with opaque-2 in repressing zein synthesis. In the double mutant o2Mc the accumulation of zein is reduced to less than 10% of that of the normal endosperm. The control on zein synthesis exerted by the double mutant is at the level of production or stability of translatable zein mRNAs. The double mutant o2Mc germinates well offering the opportunity of using it in biochemical and molecular studies related to storage protein synthesis; the reduced endosperm weight of o2Mc negates its practical utilization in breeding maize for quality.

Genes for zein subunits on maize chromosome 4.

This paper maps nine genes coding for zein subunits on maize chromosome 4. Six of them (Zp6h, Zp10, Zp14, Zp15, Zp22) encode for subunits with a molecular weight of 22 Kd (kilodaltons), while three (Zp27, Zp28, Zp30) code 20-kd subunits. The six 22-kd related genes are not contiguous but are scattered on both chromosome arms, whereas Zp27, Zp28, and Zp30 are more tightly linked in the chromosome short arm in a segment 5 crossover units long. The organization of zein genes on chromosome 4 shows a close analogy with that of zein loci on chromosome 7. This suggests that both maize chromosomes evolved by duplication of short segments.

Clustering of genes for 20 kd zein subunits in the short arm of maize chromosome 7.

Zein is the major storage protein of the endosperm of maize kernels. When this alcohol-soluble protein is subjected to SDS polyacrylamide gel electrophoresis, it is resolved into four fractions of different molecular weight: 10, 14, 20 and 22 kilodaltons (kd). Each fraction is heterogeneous with respect to isoelectric pH. For example, the 20 kd fraction contains at least seven subfractions as revealed by isoelectric focusing in polyacrylamide gels. In this report, we present evidence that the structural genes coding for the 20 kd proteins are clustered on the short arm of chromosome 7, a region that also bears loci regulating endosperm zein biosynthesis [opaque-2 (02) and defective endosperm-B30 (De(*)-B30)]. The organization of these zein genes suggests that the evolution of at least some of the maize genome has occurred as the result of repeated duplication and divergence of chromosome segments.

Carrier detection in Duchenne muscular dystropy.

We investigated the number of echinocytes, the serum hemopexin level, and spectrin band II phosphorylation in the blood of normal subjects, patients, and carriers of Duchenne dystrophy. The patients and carriers exhibited quantitatively significant differences with respect to controls.

Deformed erythrocytes in muscular dystrophies.

Because of previous reports of a possible correlation between echinocytogenesis and muscular dystrophies, we investigated the time-dependent development of echinocytes in the blood of normal subjects, patients, and healthy carries of Duchenne dystrophy. There was a quantitatively significant increase of echinocytes in patients and carriers.

[Erythrocyte changes (echino- and stomatocytic) in muscular dystrophy: research on possible applications in diagnosis and eugenics]. / "Il problema delle alterazioni eritrocitarie (echino e stomatocitiche) nella distrofia muscolare: ricerche sulle possibili applicazioni nella diagnostica e nell'eugenetica".

The Authors, after a brief review of the factors which influence the echino and stomatocytic erythrocyte's deformations and of the biochemical basis of these alterations, report the comparative study of the echino-stomatocytogenesis in both normal subjects and myodystrophic patients. In order to investigate whether this phenomenon is more developed in pathological condition, the results confirm that between normal subjects and myodystrophic patients or healthy carriers there is a quantitative significant difference which can be utilized for diagnostic and eugenic purposes. To obtain reliable results, the evaluation should be made at regular intervals of time from the blood drawing and after the exclusion of the presence of other disease or echino-stomatocytogenetic factors (drugs, etc.).