Wallerian degeneration of the pontocerebellar fibers

Two cases of pontine infarct with Wallerian degeneration (WD) of the pontocerebellar fibers are described. WD of pontocerebellar fibers, seen bilaterally along the transverse pontine fibers, is more visible in the middle cerebellar peduncles and extends into the white matter of the cerebellar hemispheres. Understanding the anatomy of the white matter and the temporal evolution of this degeneration is essential in identifying WD.     

Modulation of clinical expression of plaque-induced gingivitis: effect of incisor crown form

Evidence indicates that incisor crown form correlates with clinical periodontal features. It was hypothesized that incisor crown form may explain subject differences in gingivitis expression. The present experimental gingivitis study aimed to assess the effect of incisor crown form on plaque accumulation and gingival inflammation, and on individual susceptibility to plaque-induced gingivitis. Eighty-five periodontally healthy subjects were evaluated. A negative correlation was found between incisor crown width/crown length ratio and bleeding score (p = 0.045). From the 85 subjects, two groups of subjects with either 'long-narrow' or 'short-wide' incisor form were identified. The 'long-narrow' group had a significantly higher bleeding score than the 'short-wide' group (p = 0.014). No significant differences were found in the incisor crown width/crown length ratio between previously identified 'high responder' and 'low responder' subjects (Trombelli et al., 2004a). In conclusion, incisor crown form appears to affect the bleeding response of inflamed gingival tissues, while it exerts no influence on explaining differences in individuals' susceptibility to plaque-induced gingivitis.     

Cytologic aspects of the nasal respiratory epithelium throughout the menstrual cycle

A prospective study was performed to investigate the changes in nasal cytology that occur in healthy premenopausal women throughout the menstrual cycle. Eighty-eight women with an ovulatory menstrual cycle underwent nasal sampling with a cytobrush by direct vision of the middle and inferior nasal turbinates during the follicular, periovular, and luteal phases of the menstrual cycle, and the specimens were evaluated with the maturation index. Hematoxylin-eosin staining showed the cytologic aspects of the nasal respiratory epithelium and of vaginal smears according to the three different phases of the menstrual cycle. Along with the vaginal cells, the nasal respiratory epithelium is an ovarian steroid target.     

beta-globin DNA in maternal plasma as a molecular marker of pre-eclampsia

OBJECTIVES: Levels of cell-free foetal DNA in maternal plasma are higher in the presence of clinical features of pre-eclampsia (PE). However, currently, this method is informative only in women bearing a male foetus, by amplification of Y-specific sequences. In the present study, we overcame this limitation by examining quantitative distribution of beta-globin, a foetal gender-independent DNA marker. METHODS: We quantified beta-globin concentrations in the plasma of 207 pregnant women: control group, 164 subjects; affected group, 43 women affected by PE (n = 43). beta-globin concentrations were converted into multiples of the median of the controls (MoM), in order to assess the possible different distribution of beta-globin MoM in cases and controls. RESULTS: Adjusted MoM values were as follows: controls, 1.00 +/- 0.71; affected group 4.03 +/- 3.77 (p-value < 0.001). Among the PE affected cases, MoM beta-globin values of cases with foetal growth restriction (FGR) were almost twice as great as those cases without FGR (p-value = 0.003). CONCLUSION: beta-globin levels are higher in the plasma of pregnant women with PE, especially in those cases complicated with FGR, and do not depend on foetal gender. Such a molecular marker can potentially be used in evaluating the pathophysiological severity of PE.     

Crystalloid preload versus rapid crystalloid administration after induction of spinal anaesthesia (coload) for elective caesarean section

Current methods of crystalloid preload administration prior to spinal anaesthesia for elective caesarean section are relatively ineffective in preventing hypotension. This study examined the relevance of the timing of the fluid administered. Fifty women were randomly allocated to receive either 20 ml x kg(-1) of crystalloid solution during 20 minutes prior to induction of spinal anaesthesia (preload), or an equivalent volume by rapid infusion immediately after induction (coload). Significantly more patients in the coload group did not require vasopressor therapy pre-delivery (P=0.047). The coload group required a lower median dose (P=0.03) and a lower median number (P=0.04) of ephedrine doses for the treatment of maternal hypotension pre-delivery. There was no between-group difference in either the total cumulative dose, or in the total number of doses of ephedrine. Neonatal outcomes among the two groups were similar. Rapid crystalloid administration after, rather than over 20 minutes before the induction of spinal anaesthesia for elective caesarean section, may be advantageous in terms of managing maternal blood pressure prior to delivery.     

Parapharyngeal lymph node metastasis: an unusual presentation of papillary thyroid carcinoma

BACKGROUND: Parapharyngeal space nodal metastases are usually secondary to malignancies of the pharynx and sinonasal tract, although localization of lymphomas is also possible. Parapharyngeal metastases arising from thyroid papillary carcinoma are instead an exceedingly rare event, with only 10 cases reported up to now in the literature. METHODS: We describe two cases of parapharyngeal metastasis from thyroid papillary carcinoma in a man and a woman, aged 40 and 52 years, respectively. RESULTS: Both patients had a lesion that clinically appeared to be located in the parapharyngeal space; they underwent CT and MRI, which detected a cystic mass in the poststyloid compartment. In the first patient, fine-needle aspiration cytology failed in identifying the histologic nature of the lesion, which was excised through a transcervical approach. A diagnosis of metastatic thyroid papillary carcinoma was rendered and therefore the patient underwent total thyroidectomy. In the second patient, a total thyroidectomy, previously scheduled for multinodular goiter, was performed along with the removal of the parapharyngeal mass. Definitive histologic findings revealed that the two parapharyngeal masses were cystic metastases from a thyroid papillary carcinoma. Both patients received postoperative 131I treatment. Twenty-four months after surgery, the first patient is free of disease, whereas the second one has clear signs of abnormal 131I uptake in the lungs. CONCLUSIONS: The differential diagnosis of a parapharyngeal poststyloid mass should also include metastasis from thyroid papillary carcinoma. When the lesion displays a cystic appearance on imaging, it is advisable to rule out a thyroid primary by ultrasonographic examination. The occurrence of a metastasis in such unusual site, even though rarely reported, does not seem to significantly affect the prognosis of the disease.     

Molecular bilateral symmetry of natural products: prediction of selectivity of dimeric molecules by density functional theory and semiempirical calculations

A literature survey and theoretical calculations have been applied to explore bilateral symmetry in natural product systems. Molecular bilateral symmetry is defined to include C(2) (sigma plane or axis), C(s)(), and C(2)(v)() point groups in molecules. Natural products that possess chirality in the form of C(2)-axes or sigma planes of symmetry are present in higher proportions (69%) compared to molecules bearing achiral C(s)() or C(2)(v)() point groups (14% and 16%, respectively). Density functional theoretical and semiempirical calculations indicate that the dimers 3,3'-dibromo-5,5'-[N-(2-(3-bromo-4-hydroxyphenyl)ethyl)-2-hydroxyiminoacetamide]biphenyl-2,2'-diol (1), (S,S)-1,2-bis(2-amino-3H-imidazol-4-yl)-(R,R)-3,4-bis(1H-pyrrole-2-amido)cyclobutane (2), 2-oxo-dimethyl-1,3-bis(3,4-dibromobenzene-1,2-diol) (11), 1,7-bis(4-hydroxy-3-methoxyphenyl)hepta-1,6-diene-3,5-dione (12), and bis(5-isopropyl-8-methylazulene)methane (13) evolve more energy per connecting bond than the corresponding trimers or tetramers would. This we propose is a guiding parameter that may adjust molecule growth. The corresponding trimers, tetramers, or higher oligomers of 1, 2, and 11-13 appear to represent "missing" compounds in nature. Natural products 1, 2, and 11-13, having 3-fold and higher levels of symmetry, would founder on the lack of a facile method of synthesis and on the prohibitively high-energy costs caused by steric crowding at their core.     

A new method for the extraction and classification of single motor unit action potentials from surface EMG signals

It has been shown that multi-channel surface EMG allows assessment of anatomical and physiological single motor unit (MU) properties. To get this information, the action potentials of single MUs should be extracted from the interference EMG signals. This study describes an automatic system for the detection and classification of MU action potentials from multi-channel surface EMG signals. The methods for the identification and extraction of action potentials from the raw signals and for their clustering into the MUs to which they belong are described. The segmentation phase is based on the matched Continuous Wavelet Transform (CWT) while the classification is performed by a multi-channel neural network that is a modified version of the multi-channel Adaptive Resonance Theory networks. The neural network can adapt to slow changes in the shape of the MU action potentials. The method does not require any interaction of the operator. The technique proposed was validated on simulated signals, at different levels of force, generated by a structure based surface EMG model. The MUs identified from the simulated signals covered almost the entire recruitment curve. Thus, the proposed algorithm was able to identify a MU sample representative of the muscle. Results on experimental signals recorded from different muscles and conditions are reported, showing the possibility of investigating anatomical and physiological properties of the detected MUs in a variety of practical cases. The main limitation of the approach is that complete firing patterns can be obtained only in specific cases due to MU action potential superpositions.     

Effects of aminoguanidine and cyclooxygenase inhibitors on nitric oxide and prostaglandin production, and nitric oxide synthase and cyclooxygenase expression induced by lipopolysaccharide in the estrogenized rat uterus

BACKGROUND/OBJECTIVE: The aim of our study was first to investigate if there exists an interaction between nitric oxide (NO) and prostaglandin (PG) generation in the estrogenized rat uterus challenged by lipopolysaccharide (LPS), and, secondly, which isoforms of nitric oxide synthase (NOS) and cyclooxygenase (COX) participate in this process. METHODS: To study the effect of LPS and to characterize the isoenzymes involved in the process, specific inhibitors of iNOS (aminoguanidine) and COX-II (meloxicam, nimesulide) and non-specific of COX (indomethacin) were injected intraperitoneally to determine their effect on NO and PG production, and on NOS and COX expression induced by LPS in estrogenized rat uterus. NO production was measured by arginine-citrulline conversion assay and PGE(2)/PGF(2alpha,)by radioconversion. Enzyme expression was evaluated by Western blot analysis. RESULTS: The present work shows that iNOS inhibitor, aminoguanidine, reduced NO and PGE(2)/PGF(2alpha) production induced by LPS injection. Aminoguanidine exerts its effect over the PG metabolism by inhibiting COX-II activity and expression. On the other hand, both indomethacin, a non-selective PG inhibitor, and meloxicam, a COX-II inhibitor, stimulated NO production and reduced PGE(2)/PGF(2alpha) generation. Indomethacin also reduced COX-II and iNOS expression. CONCLUSION: These results indicate that in the estrogenized rat uterus challenged with LPS, PG and NO interact affecting each other's metabolic pathways. The above findings indicate that the interaction between NOS and COX might be important in the regulation of physiopathologic events during pregnancy.