Reading errors in patients with cerebellar vermis lesions

Dyslexia, both developmental and acquired, has been considered the result of cerebrocortical dysfunction, affecting the temporo-parieto-occipital brain regions. However, dyslexia may involve abnormalities of the magnocellular component of the visual system, leading to binocular instability or alterations of accommodation. To test the hypothesis of cerebellar involvement in the reading process – justified by its emergent role in language and cognition – we studied 10 patients with cerebellar vermis/paravermis lesions using reading tests and we compared the results with those produced by 10 normal volunteers. The data obtained demonstrate an increased number of reading mistakes in the patient group, resulting from a possible alteration of the diffuse connection system from the cerebellum to different cerebrocortical and subcortical structures. Acquired dyslexia due to cerebellar impairment may be due to oculomotor alteration or, more subtly, to the intimate cerebellar-encephalic projections, connecting the cerebellum to the attentive and alerting processes and to the language system. We discuss the data with an overview of literature. Received: 22 May 2001, Received in revised form: 14 September 2001, Accepted: 25 September 2001     

Theoretical perspectives and applications of group learning in PBL

An essential part of problem-based learning (PBL) is group learning. Thus, an in depth understanding of the theoretical underpinnings of group learning in PBL allows educators to bridge theory and practice more effectively thus providing ideas and tools to enhance PBL practices and research. The theory-driven applications examined in this article establish grounds for future research in PBL. The purpose of this article is to describe and examine two theoretical perspectives of group learning in PBL and their potential applications to improve educational practice. They include: (1) social interdependence theory and the meaning of positive interdependence, (2) socio cognitive theory of networked expertise and the concept of knowledge creation in innovative knowledge communities (IKC). Potential applications include the following: development of instructional material to foster positive interdependency using concept maps; formal and structured use of peer feedback throughout PBL courses to promote individual and group accountability; creation and sharing of new knowledge about different topics within and across IKC; and use of rotating students with hybrid abilities across PBL groups to foster distributed cognition.     

Use of endoscopic stents to treat anastomotic complications after bariatric surgery

BACKGROUND: Complications after bariatric surgery often require longterm parenteral nutrition to achieve healing. Recently, endoscopic treatments have become available that provide healing while allowing for oral nutrition. The purpose of this study was to present outcomes of the largest series to date treating staple line complications after bariatric surgery with endoscopic covered stents. STUDY DESIGN: A retrospective evaluation was performed of all patients treated for staple line complications after bariatric surgery at a single tertiary care bariatric center. Acute postoperative leaks, chronic gastrocutaneous fistulas, and anastomotic strictures refractory to endoscopic dilation after both gastric bypass and sleeve gastrectomy were included. RESULTS: From January 2006 to June 2007, 19 patients (11 with acute leaks, 2 with chronic fistulas, and 6 with strictures) were treated with a total of 34 endoscopic silicone covered stents (23 polyester, 11 metal). Mean followup was 3.6 months. Immediate symptomatic improvement occurred in 90% (91% of acute leaks, 100% of fistulas, and 84% of strictures). Oral feeding was started in 79% of patients immediately after stenting. Resolution of leak or stricture after stent treatment occurred in 16 of 19 patients (84%). Healing of leak, fistula, and stricture occurred at means of 33 days, 46 days, and 7 days, respectively. Three patients (1 with leak, 1 with fistula, and 1 with stricture) had unsuccessful stent treatment. Migration of the stent occurred in 58% of 34 stents placed. Most migration was minimal, but three stents were removed surgically after distal small bowel migration. There was no mortality. CONCLUSIONS: Treatment of anastomotic complications after bariatric surgery with endoscopic covered stents allows rapid healing while simultaneously allowing for oral nutrition. The primary morbidity is stent migration.     

Onychomycosis in systemic lupus erythematosus: a case control study

OBJECTIVE: Immunosuppressed patients are prone to develop onychomycosis. In systemic lupus erythematosus (SLE) there are no previous studies. We aimed to establish the prevalence, clinical characteristics, and organisms causing onychomycosis in SLE patients compared with controls. METHODS: Fifty consecutive patients with SLE seen on an outpatient basis and 50 sex and age matched controls. Samples were obtained when abnormal nails were found: distal and lateral subungual onychomycosis (DLSO), white superficial, proximal subungual (PSO), endonyx, and total dystrophic (TDO). The nail specimens were evaluated in a blinded fashion, by mycologic examination and culture. RESULTS: Of the SLE patients, there were 12 (24%) with onychomycosis confirmed. The distribution of the clinical forms were TDO 6/12 (50%), DLSO 4/12 (33%), and PSO 2/12 (17%). The causative organisms were isolated in 6 cases: Trichophyton rubrum 3/6 (50%), Trichophyton mentagrophytes 2/6 (33%), Microsporum canis 1/6 (17%). Direct microscopy examination revealed fungal elements in the other 6 cases. Of the 50 controls, 4 (8%) presented onychomycosis [p = 0.029; OR 3.63 (95% CI 1.04-14.68)]: DLSO 2/4 (50%), and TDO 2/4 (50%). Trichophyton rubrum was isolated in 1 and Trichophyton mentagrophytes in 1 (50%). CONCLUSION: These data suggest a higher prevalence of onychomycosis in SLE versus controls, the predominant organism was Trichophyton rubrum, an anthropophilic dermatophyte. Toenails were more frequently affected and the most common clinical presentation was TDO. PSO, a rare pattern in immunocompetent subjects, was exclusively found in the lupus group.     

Stress Concentration Factors in Excavation Repairs of Surface Defects in Forgings and Castings

This paper provides an analytical formula for the theoretical stress concentration factor in a common type of excavation repair for large forgings and castings. Mechanical components obtained with these processes are often subjected to superficial defects. As the rejection of such pieces is out of question, given the relevant size and costs associated with them, usual industrial practice consists in the removal of the defect and a portion of the surrounding material through milling processes. The authors have selected a reference geometry of the excavation to be left on the mechanical pieces, which can be easily controllable in practice by three operating parameters. Then, the domain of existence of such a repair was investigated on a sequence of discrete points, by means of FEA, obtaining for each, the values of the stress concentration factor K_t. Finally, through polynomial regression, the K_t functions have been accurately approximated by a sixth degree polynomial formulation, which, given a triplet of dimensional geometric parameters, is able to compute the stress concentration factor K_t, with an error that never exceeds 8%.     

Contact Burn with Blister Formation in Children Treated with Sennosides

Eight children treated for severe constipation with sennosides unexpectedly developed contact burns with blisters secondary to the use of these laxatives. All patients wore diapers, and the injuries occurred overnight. To avoid this side effect, we recommend that patients treated with sennosides, especially those in diapers, receive the medication at a time that allows for bowel movements to occur during the day and not overnight.     

Clearance and Glomerular Localization of Preformed DNP Anti-DNP Immune Complexes

The in vivo behaviour of well-defined immune complexes in rats was studied using complexes derived from DNP-conjugated bovine thyroglobulin (DNP-BTG) and purified specific goat anti-DNP IgG. Both clearance and glomerular localization were mainly dependent on the nature of the antigen. Soluble immune complexes formed with DNP17-BTG were cleared faster and showed a more marked localization in the glomerular mesangium than complexes formed with DNP3.4-BTG. A slight increase in the antibody to antigen ratio seemed to facilitate mesangial localization of soluble immune complexes. Insoluble immune complexes showed temporary localization as microemboli in the lumina of glomerular and peritubular capillaries. This study thus shows that not only the size and composition of the complexes but also the nature of the antigen within the complex can influence the clearance and organ localization of circulating immune complexes.