Localization of the cyclic ADP-ribose-dependent calcium signaling pathway in bovine rod outer segments

PURPOSE: Calcium ions play a pivotal role in phototransduction. In this study, the presence and functional role of the adenosine diphosphoribosyl (ADPR)-cyclase-cyclic ADP-ribose (cADPR) system in bovine retinal rod outer segments (ROS) was investigated. METHODS: A Ca(2+) release from osmotically intact ROS discs elicited by cADPR was studied in the presence of the Ca(2+) tracer fluo-3. Endogenous cyclic guanosine diphosphate ribose (cGDPR) formation in discs was investigated by spectrophotometric detection of its synthesis from nicotinamide guanine dinucleotide (NGD(+)). ADPR-cyclase was also investigated at a structural level on mildly denaturing SDS-PAGE by production of cyclic inosine diphosphate ribose from nicotinamide hypoxantine dinucleotide (NHD(+)). Western immunoblot analysis with a specific antibody was conducted to verify the presence of ryanodine-sensitive Ca(2+) channels (RyRs) in ROS discs. RESULTS: cADPR-dependent Ca(2+) release was a linear function of extravesicular free Ca(2+) concentration, between 200 and 900 nM Ca(2+). When free Ca(2+) was 203 +/- 10 nM the mean Ca(2+) release was 23 +/- 3 pmol/mL per milligram protein. The average rate of cGDPR production was 13 +/- 2 nmol cGDPR/min per milligram protein, by a putative enzyme with an apparent molecular mass of 53 +/- 1 kDa. ROS ADPR-cyclase was localized in the membranous fraction. No nicotinamide adenine dinucleotide glycohydrolase (NADase) activity was detected. The presence of RyR channels in pure disc preparations was confirmed by confocal laser scanning microscopy. CONCLUSIONS: A cADPR metabolism may be present in retinal ROS discs, which may be Ca(2+) stores operated by cADPR. A model is proposed for the physiological role of cADPR-mediated Ca(2+) release in bovine ROS.     

Absence of cerebrospinal fluid oligoclonal bands is associated with delayed disability progression in relapsing-remitting MS patients treated with interferon-beta

To determine whether combined studies of Mini-Mental State Examination (MMSE) and brain single photon emission CT (SPECT) would provide more useful means of differentiating between dementia with Lewy bodies (DLB) and Alzheimer's disease (AD), we studied 36 patients with probable DLB and 96 patients with probable AD. DLB patients had significantly better performance on word recall, but more impaired attention and copying than AD patients. We confirmed that a weighted score derived by Ala et al. [Ala, T.A., Hughes, L.F., Kyrouac, G.A., Ghobrial, M.W., Elble, R.J. The Mini-Mental State exam may help in the differentiation of dementia with Lewy bodies and Alzheimer' disease. Int J Geriatr Psychiatry 2002;17:503–9]: (Attention − 5/3 · Memory + 5 · Construction), was helpful in discriminating between DLB and AD. SPECT study revealed that medial occipital perfusion significantly decreased in DLB patients than AD patients. Combined studies of MMSE and brain SPECT achieved a high discrimination between DLB and AD with a sensitivity of 81% and a specificity of 85%, suggesting that there is a useful and practical approach to differentiate DLB from AD. Our findings will need to be substantiated in an independent and prospective study sample.     

Divergent functions of the proneural genes Mash1 and Ngn2 in the specification of neuronal subtype identity

The neural bHLH genes Mash1 and Ngn2 are expressed in complementary populations of neural progenitors in the central and peripheral nervous systems. Here, we have systematically compared the activities of the two genes during neural development by generating replacement mutations in mice in which the coding sequences of Mash1 and Ngn2 were swapped. Using this approach, we demonstrate that Mash1 has the capacity to respecify the identity of neuronal populations normally derived from Ngn2-expressing progenitors in the dorsal telencephalon and ventral spinal cord. In contrast, misexpression of Ngn2 in Mash1-expressing progenitors does not result in any overt change in neuronal phenotype. Taken together, these results demonstrate that Mash1 and Ngn2 have divergent functions in specification of neuronal subtype identity, with Mash1 having the characteristics of an instructive determinant whereas Ngn2 functions as a permissive factor that must act in combination with other factors to specify neuronal phenotypes. Moreover, the ectopic expression of Ngn2 can rescue the neurogenesis defects of Mash1 null mutants in the ventral telencephalon and sympathetic ganglia but not in the ventral spinal cord and the locus coeruleus, indicating that Mash1 contribution to the specification of neuronal fates varies greatly in different lineages, presumably depending on the presence of other determinants of neuronal identity.     

Is the occurrence of the empty follicle syndrome a predictor that a subsequent stimulated cycle will be an unfavourable one?

Several hypotheses have been advanced to explain empty follicle syndrome (EFS) but it remains a controversial topic. This paper reports experience with three IVF cycles in which no oocytes were collected. In all cases, an additional IVF cycle was performed. The ovarian stimulation protocol, ultrasound and hormonal surveillance methods, human chorionic gonadotrophin timing and oocyte retrieval technique were similar in all patients. The assessment of additional cycles demonstrated a poor response in terms of oocyte quality, since the number of mature oocytes was low despite the high number of oocytes collected. Thus, the data suggest that in these patients, EFS should be considered as a borderline form of poor response to ovarian stimulation. If this is confirmed, EFS should be a recurrent event and an empty cycle could be a good predictor that a subsequent stimulated cycle will be an unfavourable.     

Dissociable distal and proximal motor components: Evidence from perseverative errors in three apraxic patients

In the present study we analysed the perseverative behaviour of three apraxic patients (FG, CEO, and VCR) while they were pantomiming the use of common objects and during their real use. The three patients were found to perseverate from one trial to later ones aspects of a given action in the pantomiming and in real use tasks. In particular, our main result was a striking double dissociation between patients in perseverating hand and arm movements. Patients FG and CEO made more perseveration errors involving the hand than VCR did, whereas the perseverative errors made by VCR involving the arm were more numerous than those made by FG and CEO. The patients differed also in other aspects of the perseverations, e.g., their median lags. Results are used to exend previous theories developed in the linguistic domain to that of actions.     

Epidemiology and biology of nematodofauna affecting Testudo hermanni, Testudo graeca and Testudo marginata in Italy

Tortoises of the genus Testudo living in Italy are Testudo hermanni, Testudo graeca and Testudo marginata. Although a great deal of information has been acquired on the internal medicine and surgery on these animals, little is known of their parasitological fauna. A survey on the presence of gastro-intestinal parasitic nematodes in tortoises bred in Italy was carried out to acquire extensive epidemiological data. Stool samples of 62 tortoises (37 T. hermanni hermanni, 13 T. graeca, 6 T. hermanni boettgeri and 6 T. marginata) were macroscopically examined and subjected to qualitative (flotation and Baermann techniques) and quantitative (McMaster technique) microscopic examinations. Adult nematodes were identified using morphological keys. Eggs of oxyurids (species indistinguishable) and adults of Alaeuris numidica, Mehdiella microstoma, Mehdiella uncinata, Tachygonetria longicollis, Tachygonetria conica and Tachygonetria palearcticus (Oxyurida, Pharyngodonidae); larvae and adults of Atractis dactyluris (Ascaridida, Atractidae); and eggs and adults of Angusticaecum holopterum (Ascaridida, Ascarididae) were identified in all animals >1 year, whereas all tortoises <1 year of age were parasite-free. Moreover, this study reports for the first time A. numidica and M. microstoma in T. marginata. This work shows that nematodes affecting tortoises are diffused in Italy and highlights the need to investigate their epidemiology more in depth.     

Excisional biopsy with wire localisation of non-palpable breast lesions: indications and limitations

Preoperative localisation of non-palpable breast lesions is necessary for excisional biopsies. This can be achieved with methods such as anchor wire, charcoal marking, or radio-guided localisation. The aim of the present study was to evaluate retrospectively our experience with the wire localisation technique. One hundred and eighty-two patients with non-palpable breast lesions (diameter: 0.4-1.5 cm) were operated on under local anaesthesia. Intraoperative X-rays were performed in all cases. No serious perioperative complications occurred. Three patients (2 with postoperative haematomas and 1 with wound infection) underwent conservative therapy. The lesions were benign in 67/182 patients (37%), ductal and/or lobular invasive cancer in 42 (23%), carcinoma in situ in 23 patients (12.5%) and ADH-ALH in 50 patients (27.5%). Our experience confirms that wire localisation biopsies constitute an excellent method for the excision of non-palpable breast lesions. This technique is characterised by high reliability (100% total excisions) and assures a prognostic evaluation of high-risk lesions such as ductal an/or lobular atypical hyperplasia.