Idiopathic sudden sensorineural hearing loss and ménière syndrome: The role of cerebral venous drainage.

OBJECTIVES: To evaluate the influence of cerebral venous drainage on the pathogenesis of idiopathic sudden sensorineural hearing loss (ISSHL) and Ménière syndrome (MD). DESIGN: Observational, prospective, cohort study. SETTING: ENT and Cardiology Departments (University of Bari, Policlinico Hospital, Bari, Italy). PARTICIPANTS: We enrolled 59 consecutive patients (32 males, mean age 53.05 + 15.37 years): 40 ISSHL and 19 MD. MAIN OUTCOME MEASURE: All patients underwent physical examination, biochemical evaluation (glycemic and lipid profile, viral serology, C reactive protein, etc), audiometric (tonal, vocal, vestibular evoked myogenic potentials and auditory brainstem response test) and impedentiometric examination. The pure tone average (PTA) was calculated for the following frequencies: 250, 500, 1000, 2000, 3000, 4000, 8000. An echo-color Doppler evaluation of the venous cerebral veins, internal jugular (IJV) and vertebral veins (VV) at supine and 90° position was performed. RESULTS: No morphological alterations were found both in patients and controls. There were no signs of stenosis, blocked flow, membranes, etc. We found lower minimum, mean and maximum velocities in distal IJVs (P = .019; P = .013; P = .022; respectively) and left VVs (P = .027; P = .008; P = .001; respectively) in supine (0°) position in both MD and ISSHL patients as compared to controls. The same was for orthostatic position (90°). We found negative correlations between the velocities in extracranial veins and PTA values: therefore, the worst the audiometric performance of the subjects, the lower the velocities in the venous cerebral drainage. CONCLUSIONS: Idiopathic sudden sensorineural hearing loss and Ménière syndrome patients showed altered venous flow in IJVs and VVs as compared to controls, independently from posture. This different behavior of venous tone control can influence the ear performance and may have a role in the pathogenesis of both diseases.

Expression of p16 in abnormal pap-tests as an indicator of CIN2+ lesions: a possible role in the low grade ASC/US and L/SIL (Ig) cytologic lesions for screening prevention of uterine cervical tumours.

The aim of this study was to assess the validity of protein p16 expression as an indicator of progression in lesions as ASC-US and L-SIL. For this purpose, we examined 246 cytological samples (91 ASC-US, 60 L-SIL, 36 ASC-H, 59 H-SIL) of which 151 were conventional Pap-tests (CC) and 95 in liquid based cytology (LBC) with colposcopic and histology follow-up. The results showed that in the positive p16 Pap-tests a 59% PPV vs CIN2+ in all cytologic diagnoses compared to 43% in cytologic reading alone. 96% of HG cytologic lesions were positive for p16, and the data showed good correlation between positivity for p16 in the cytologic preparations and the presence of CIN2+ lesions in the histologic test (chi-square for trend p < 0.0001). The sensitivity, specificity and NPV were 93%, 52% and 91%, respectively, in all cytologic diagnostic categories. P16 was positive in 46% of ASC-US and 53% of L-SIL. The PPV vs expressed CIN2+ was higher than that observed in cytologic reading (48% vs 26%, and 31% vs 20%, respectively). The sensitivity was 83%, the specificity 67% and 54%, respectively, and the VNP was 92% and 93%. It is possible to design algorithms for colposcopic follow-up that can reduce the need to obtain a follow-up. The future application of this test may allow the creation of a bio-molecular automated pap test.

Role of the core region of the PufX protein in inhibition of reconstitution of the core light-harvesting complexes of Rhodobacter sphaeroides and Rhodobacter capsulatus.

PufX, the protein encoded by the pufX gene of Rhodobacter capsulatus and Rhodobacter sphaeroides, has been further characterized. The mature forms of these proteins contain 9 and 12 fewer amino acids, respectively, at the C-terminal end of the protein than are encoded by their pufX genes. To identify the portion of PufX responsible for inhibition of LH1 formation in reconstitution experiments, different regions (N-terminus and several core regions containing different lengths of the C-terminus) of Rb. sphaeroides and Rb. capsulatus PufX were chemically synthesized. Neither the N- nor C-terminal polypeptides of Rb. sphaeroides were inhibitory to LH1 reconstitution. However, all core segments were active, causing 50% inhibition at a concentration ratio of between 3:1 and 6:1 relative to the LH1 alpha-polypeptides whose concentrations were 3-4 microM. CD measurements indicated that the core segment containing 39 amino acids of Rb. sphaeroides PufX exhibited 47% alpha-helix in trifluoroethanol while the core segment containing 43 amino acids of Rb. capsulatus PufX exhibited 59 and 55% alpha-helix in trifluoroethanol and in 0.80% octylglucoside in water, respectively. Approximately 50% alpha-helix was also indicated by a PHD (Burkhard-Rost) structure prediction. Binding of bacteriochlorophyll to these PufX core segments is implicated.

Isolation of the PufX protein from Rhodobacter capsulatus and Rhodobacter sphaeroides: evidence for its interaction with the alpha-polypeptide of the core light-harvesting complex.

Using mutant strains of Rhodobacter capsulatus and Rhodobacter sphaeroides in which the pufX gene had been deleted, it was possible to identify by HPLC membrane protein components present in pufX+ cells but absent in pufX- cells. In parallel preparations, membrane proteins soluble in chloroform/methanol containing ammonium acetate were first extracted from lyophilized membrane fractions of the pufX+ cells and separated from pigments and larger protein material by gel-filtration chromatography. Protein-containing fractions were examined by HPLC, and several peaks were collected from pufX+ material that were not present in pufX- material. From N-terminal amino acid sequencing, the PufX protein of Rb. capsulatus was identified, and from positive interaction with a PufX protein antibody, the Rb. sphaeroides PufX protein was identified. Although overall yields were very small, sufficient quantities of these proteins were isolated to evaluate their effect on the reconstitution of the core light-havesting antenna (LH1) and its subunit complex. From the behavior of the PufX protein and the alpha-polypeptide of LH1 on HPLC, qualitative evidence was obtained that the two proteins have a high affinity for each other. In reconstitution assays with bacteriochlorophyll (Bchl) and the LH1 alpha- and beta-polypeptides of Rb. capsulatus, the PufX protein of Rb. capsulatus was inhibitory to LH1 formation at low concentration. A similar inhibition was exhibited by Rb. sphaeroides PufX protein for reconstitution of LH1 with Bchl and the LH1 alpha- and beta-polypeptides of Rb. sphaeroides. In both cases, the ratios of concentrations of the PufX protein to the alpha-polypeptide causing 50% inhibition were approximately 0.5. Formation of the heterologous (alpha beta) subunit-type complex formed with Bchl and the alpha- and beta-polypeptides of LH1 of Rb. capsulatus was also inhibited by low concentrations of the Rb. capsulatus PufX protein (approximately 50% inhibition at PufX:alpha-polypeptide ratios = 0.5). However, neither PufX protein inhibited formation of a homologous (beta beta) subunit-type complex, which indicates that the PufX proteins do not interact with the beta-polypeptides.

Enzymatic and chemical cleavage of the core light-harvesting polypeptides of photosynthetic bacteria: determination of the minimal polypeptide size and structure required for subunit and light-harvesting complex formation.

To ascertain the minimal structural requirements for formation of the subunit and core light-harvesting complex (LH1), the alpha- and beta-polypeptides of the LH1 from three purple photosynthetic bacteria were enzymatically or chemically truncated or modified. These polypeptides were then used in reconstitution experiments with bacteriochlorophyll a (BChla), and the formation of subunit and LH1 complexes was evaluated using absorbance and circular dichroism spectroscopies. Truncation or modification outside of the conserved core sequence region of the polypeptides had no effect on subunit or LH1 formation. However, the extent of formation and stability of the subunit and LH1 decreased as the polypeptide was shortened inside the core region within the N-terminal domain. This behavior was suggested to be due to the loss of potential ion-pairing and/or hydrogen-bonding interactions between the polypeptides. While the spectroscopic properties of the subunit complexes generated using truncated polypeptides were analogous to those obtained using native polypeptides, in some cases the resulting LH1 complex absorption was blue-shifted relative to the control. Thus, truncation within the N-terminal domain may have long-range effects on the immediate BChla binding environment, since the putative BChla binding site resides near the C-terminal end of the polypeptides. It was also demonstrated that the His located within the membrane-spanning domain on the N-terminal end of the beta-polypeptide is not participating in ligation of the BChla in the reconstituted subunit and therefore probably not in LH1.

[Immunological aspects of dental transplants]. / Aspetti immunobiologici dei trapianti dentari.

The recent literature on dental transplants in man and experimental models is reviewed. The histopathological and immunological aspects of the methods and results are critically analysed in function of the clinical applicability of this alternative to prosthesis. The different effects of mature tooth and germ transplants are considered in the light of experiments on various mammals, together with the contribution made by the various dental tissues to the taking of the transplant, and its acceptance or rejection by the host. Finally, questions associated with the establishment of a teeth bank and its potential creation of a sufficient supply of organs for transplantation are discussed.