Simple Trends in NMR Spectra of Vinyl Polymers: The 1H NMR Spectrum of Poly(propylene)

Summary: The tacticity spreading of chemical shifts in the proton NMR spectrum of poly(propylene) in solution has been analyzed first qualitatively, taking advantage of known trends in both proton chemical shift and conformational statistics of vinyl polymers as summarized in the telephone rule, and then quantitatively using ab initio computations, empirical additivity schemes of proton chemical shifts, and conformational averages according to models of different rotational isomeric states. The very good results obtained, both qualitatively and quantitatively, stem from the relatively easy parametrization of proton chemical shift and establish a successful application of the telephone rule, also for proton NMR spectra.

Anti and syn labeling of methylene hydrogens in m and r diads.     

Phosphorylated 14-3-3zeta protein in the CSF of neuroleptic-treated patients

The authors describe 12 neuroleptic-treated patients with dementia of various etiologies who showed CSF elevation of phosphorylated 14-3-3zeta and normal tau protein levels. This contrasted with elevated amounts of 14-3-3 gamma, epsilon, and unphosphorylated zeta coupled to high tau protein levels in Creutzfeldt-Jakob disease and negative 14-3-3 assay in drug-free patients with dementia. Characterization of CSF 14-3-3 isoforms and determination of tau protein level can help to distinguish different etiologies of dementia.     

"In vitro" postnatal expression of 5-HT7 receptors in the rat hypothalamus: an immunohistochemical analysis

The neurotransmitter serotonin (5-HT) is involved in various physiological functions via multiple receptor subtypes. These have been classified in seven receptor families (5-HT1-7) on the basis of their structures and functional characteristics. In this study, we examined the expression of 5-HT7 receptors in the rat hypothalamic neurons cultured "in vitro" during postnatal development. Neuronal cultures were prepared from postnatal pups P2, P3 and P5, were treated with bFGF and processed by means of immunofluorescence technique using a polyclonal 5-HT7 receptor antibody. In P2, we found a low density of 5-HT7 labeled hypothalamic bFGF-treated neurons and no 5-HT7 immunolabeling in control cultures; in P3, a moderate number of bFGF-treated neurons were observed but they were not bright. No 5-HT7 immunolabeling was found in controls. In P5, a heavy labeling of small sized bipolar neurons was seen in bFGF-treated neurons, while in control cultures, few labeled neurons with a low stained density were observed. These results suggest that 5-HT7 receptors in hypothalamic neurons begin to appear at P5 and then could be involved in many physiological implications that are not exerted at P2 and P3. This indicates that 5-HT7 receptors have a potential significance in the rat hypothalamus during early postnatal development.     

Abdominal radiography findings in small bowel anastomoses with V-BAR

PURPOSE: The aim of the present paper is to describe the normal radiological findings and the fragmentation time of the VALTRAC BAR (V-BAR). MATERIALS AND METHODS: Ten cases of Roux-en-Y jejuno-jejunostomy with anastomosis with a n.25 Valtrac ring for gastric cancer were followed up during the postoperative period by plain abdominal X-ray examination. RESULTS: Abdominal X-ray examination showed V-BAR fragmentation between day 14 and 21 after surgery. In one case only did fragmentation fail and the V-BAR migrated resulting in mechanical ileus. CONCLUSIONS: The possible non-fragmentation and migration of the V-BAR confirms the need to follow up patients with plain abdominal radiography performed at short intervals during the postoperative period.     

Reliability of panoramic radiography in evaluating the topographic relationship between the mandibular canal and impacted third molars

BACKGROUND: The authors conducted a study to evaluate the predictive value of five radiographic markers on the panoramic radiograph, or PR, to point out the relationship between the mandibular canal and the impacted third molar. METHODS: The authors evaluated the accuracy of the radiographic markers by comparing the PR with an axial computed tomographic, or CT, scan. They identified a sample of 73 third molars that showed a close relationship between the tooth roots and the mandibular canal on the PR, and then classified them on the basis of five radiographic markers. They also detected contact between the third molar and the mandibular canal on the CT scan. RESULTS: The distribution of the five radiographic markers was as follows: 37 teeth exhibited increased radiolucency, 13 exhibited superimposition, 14 exhibited interruption of the radiopaque border, 14 exhibited narrowing of the canal and seven exhibited diversion of the canal. In 11 cases, two or more markers were recognizable. The predictive values of a positive test result were as follows: increased radiolucency, 73 percent; superimposition, 38.5 percent; interruption of the radiopaque border, 71.4 percent; narrowing, 78.6 percent; and diversion, 100 percent. The authors detected contact in all of the cases that exhibited two or more markers. CONCLUSION: Increased radiolucency, narrowing and interruption of the radiopaque border, as well as the concomitant presence of two or more radiographic markers, on the PR were highly predictive of contact between the third molar and the mandibular canal. An axial CT scan probably is indicated in such cases. CLINICAL IMPLICATIONS: The results of this study may lead to some guidelines for oral surgeons evaluating whether to obtain an axial CT scan for further investigation after examining an impacted mandibular third molar via PR.     

Gummy smile: clinical parameters useful for diagnosis and therapeutical approach

In the analysis of the characteristics of a pleasant smile, a gummy smile has negative components, which most affect the esthetics of non-verbal communication. For this purpose a proposed classification based upon etiopathogenetic criteria as useful indications for a therapeutical approach is given. The nature of a high smile line can be: dento-gingival, connected to an abnormal dental eruption, which is revealed by a short clinic crown; muscular, caused by an hyperactivity of the elevator muscle of the upper lip; dento-alveolar (skeletal), due to an excessive protuberance or vertical growth of the jawbone (maxillary); lastly, a mixed nature, in the presence of more than one of the above described factors The diagnosis of gummy smile must be precocious and based, with reference to specific parameters, upon a careful analysis of the etiopathogenetic factors and the degree of seriousness of the alteration. A correct treatment plan must contemplate the possibility of an orthognatodontic, orthopedic and/or surgical therapeutic resolution considering the seriousness and complexity of the gums exposures (high smile line) in connection with the age of the subject.