Novelty and Familiarity Activations in PET Studies of Memory Encoding and Retrieval

Nine young right-handed men viewed colored pictures of people,scenes, and landscapes. Then, 24 hr later while undergoing PETscanning, they viewed previously studied (OLD) pictures in onetype of scan, and previously not seen (NEW) pictures in another.The OLD-NEW subtraction of PET images indicates familiarity,and the NEW-OLD indicates novelty. Familiarity activations,signalling aspects of retrieval, were observed in the left andright frontal areas, and posterior regions bilaterally. Noveltyactivations were in the right limbic regions, and bilaterallyin temporal and parietal regions, including area 37. These latteractivations were located similarly to novelty activations inprevious PET studies using visual words and auditory sentences,suggesting the existence of brain regions specializing in transmodalnovelty assessment The effects of novelty are seen both be haviorallyand in replicable patterns of cortical and subcortical activation.We propose a "novelty/encoding hypothesis": (1) novelty assessmentrepresents an early stage of long-term memory encoding; (2)elaborate, meaning-based encoding processes operate on the incoming information to the extent of its novelty, and therefore(3) the probability of long-term storage of information vanesdirectly with the novelty of the information.     

Upper parietal pleurectomy with resection of bullae by thoracoscopy in spontaneous pneumothorax. New perspectives from preliminary results in 20 cases]

In view of the increasing development of laparoscopic surgery and hoping to minimize thoracotomy's risks, we had the idea to perform pleurectomy as a treatment of Spontaneous Pneumothorax (S.P.) through video thoracoscopy. The operation was performed under general endobronchial anesthesia, the patient placed in the posterolateral thoracotomy position. Three trocars inserted through the 5th, 7th and 9th intercostal space, allowed the introduction of non specific thoracoscopic instruments similar to those used in laparoscopic surgery. The apical pleurectomy was delimited by the 6th rib, the internal thoracic vessels, the costovertebral sulcus and the first rib. Blebs and small bullae are now transected with application of the "EndoGIA 30". Pleural cavity was drained by F28 ans F32 tubes through the lower orifices. This procedure was performed in 18 patients presenting 20.S.P.. Operative indications were: persistent air link (7 cases), recurrence (9 cases), bullae with bridle and or anterior thoracotomy for S.P. (4 cases). One bleeding of 200 ml from a wounded intercostal vessel ligated with a clip was the sole operative hitch. Operative duration decreased from two to one hour. Average drainage duration was 3.5 dys and hospital stay 4.5 days. There was no death nor immediate complications. Post-operative pain was judged in all cases less intensive than that experienced after pleurectomy with thoracotomy. This original procedure is the first described as entirely performed through thoracoscopy with non specific instruments and hence economic impact.(ABSTRACT TRUNCATED AT 250 WORDS)     

Hepatolithiasis associated with anomalous biliary anatomy and a vascular compression. Hepatolithiasis and anomalous anatomy

Biliary tract abnormalities occur in about one of every three people, usually being minor and of no clinical significance. Major abnormalities, however, may present in an unusual manner and provide a major hazard to the unsuspecting surgeon. A patient presenting with cholangitis without jaundice or abnormal liver function tests is reported. Endoscopic retrograde cholangiography failed to demonstrate any bile ducts in the right postero-lateral segments of the liver, the "naked segment sign". A percutaneous transhepatic cholangiogram demonstrated a stricture obstructing the right posterior segmental hepatic duct with hepatolithiasis above the stricture. At operation an anomalous vessel was found at the site of the stricture. This case highlights the unusual way in which biliary tract anomalies may present and the importance of adequate pre-operative investigation.     

Rectal cancer in the Kingdom of Saudi Arabia: the King Faisal Specialist Hospital experience

BACKGROUND: No survival data have yet been published from the Kingdom of Saudi Arabia for patients with rectal cancer. The present paper reports experience with these patients over an 8-year period. METHODS: All patients referred to the King Faisal Specialist Hospital (KFSH) between March 1990 and February 1998 for the primary management of rectal cancer were entered into a computerized database. Prior to 1993 patients did not receive adjuvant therapy. Kaplan-Meier survival curves and the log-rank test were used to compare outcome data. RESULTS: There were 70 men (average age: 55.6 years) and 75 women (average age: 52.8 years). Twelve per cent of patients admitted a family history of colorectal carcinoma (CRC). Twenty-seven per cent of tumours were circumferential. Most tumours were larger than 4 cm and the lowest edge of the majority of tumours was less than 6 cm from the anal verge. Fifty-four per cent of tumours were fixed; 69% of patients received either pre-operative or postoperative radiotherapy. A total of 106 patients underwent 'curative' surgery. Equal numbers of patients had abdomino-perineal resection (APR) and anterior resection (AR) of the rectum. Thirty-five patients received blood peri-operatively (APR, 34%; AR, 12%). Major anastomotic leakage following AR occurred in two patients. Two patients died within 30 days of surgery. Ten patients were lost to follow-up. Following curative AR, eight patients had a distal resection margin of < 2 cm and two patients (Dukes' C) developed local recurrence (25%); 37 patients had a margin > 2 cm and seven developed local recurrence (18.9%). A total of 48 patients underwent curative APR, and four patients developed local recurrence (8.3%). Overall local recurrence was tumour stage-dependent (Dukes' B, 8.8%; Dukes' C, 29.3%). Recurrence was local in 13 patients. Pre-operative radiotherapy seemed to reduce average tumour size (3.6 vs 4.3 cm). The crude overall 5-year survival rate was 39%. The 5-year survival rate for patients with Dukes' stage C cancers following 'curative' surgery was 25%. CONCLUSION: Curative surgery can be performed with a relatively low requirement for blood transfusion, a low mortality and morbidity, and comparable outcomes to Western studies in spite of the large, low and often advanced stage of the tumours managed. Local recurrence rates following curative resection and re-anastomosis for low rectal cancers may be reduced by resisting patient pressure to avoid stomata.     

Phenotypic and genotypic characterization of enteroaggregative Escherichia coli isolates from pediatric population in Pakistan

Enteroaggregative Escherichia coli (EAEC) are a leading cause of diarrhea among children. The objective of this study was to define the frequency of EAEC among diarrheal children from flood‐affected areas as well as sporadic cases, determine multidrug resistance, and evaluation of virulence using an in vivo model of pathogenesis. Stool samples were collected from 225 diarrheal children from 2010 to 2011 from flood‐affected areas as well as from sporadic cases in Pakistan. Identified EAEC isolates were characterized by phylogrouping, antibiotic resistance patterns including the extended‐spectrum beta lactamase spectrum, single nucleotide polymorphism detection in gyrA and parC, and virulence potential using wax worm, G. mellonella. A total of 35 (12.5%) confirmed EAEC isolates were identified among 225 E. coli isolates. EAEC isolates displayed high resistance to tetracycline, ampicillin, and cefaclor. A total of 34.28% were ESBL positive. Single nucleotide polymorphism detection revealed 37.14% and 68.57% isolates were positive for SNPs in gyrA (A₆₆₀‐T₆₆₀) and parC (C₃₃₀‐T₃₃₀), respectively. Phylogrouping revealed that B2 phylogroup was more prevalent among all EAEC isolates tested followed by D, A, B1, and non‐typeable (NT). Infection of G. mellonella with EAEC showed that killing infective dose was 100% higher than E. coli DH5 alpha control. EAEC are prevalent among Pakistani children with diarrhea, they are highly resistant to antibiotics, and predominantly fall into B2 phylogroup. Epidemiologic surveillance of EAEC and other E. coli pathotypes is critical to assess not only the role of these pathogens in diarrheal disease but also to determine the extent of multidrug resistance among the population.     

Fluoride bioactive glass paste improves bond durability and remineralizes tooth structure prior to adhesive restoration

ObjectiveThe current study aimed at examining a fluoride containing bioactive glass (BiominF®) paste as a temporary filling material capable of remineralizing the demineralized enamel or dentin, and its ability to decrease a simulated dentinal fluids pressure on the resin/dentin interface, without affecting the shear bond strength of a universal bonding agent to enamel and dentin.Methods60 premolars were utilized for the acid resistance, trans-microradiography (TMR) and shear bond strength (SBS) experiments. Enamel and dentin discs were demineralized for 4 days to create a subsurface demineralized zone followed by applying BiominF® paste, 1.23% acidulated phosphate fluoride, or a temporary filling material for 24 h.30 extracted human non-carious third molars were utilized for the pulpal pressure experiment in which direct communication to the pulp chamber was created by cutting at a level approximately 1 mm below the cemento-enamel junction while the coronal enamel was ground to expose mid coronal dentin. The dentin surface was exposed to a simulated pulpal pressure. The dentin surfaces had BiominF® paste, an oxalate desensitizing agent, or temporary filling material followed by application of a universal adhesive system.ResultsOne way ANOVA showed that BiominF® paste remineralized effectively the demineralized enamel or dentin, did not affect the bond strength of the enamel and dentin surfaces to the tested adhesive system p < 0.05, and improved the acid resistance of the demineralized enamel and dentin against a secondary erosive challenge. Moreover, BiominF® paste decreased the nanoleakage expression in the dentin/adhesive interface exposed to a simulated pulpal pressure.SignificanceBiominF® paste may serve as a temporary filling material that may improve the longevity of adhesive restorations and help to conserve tooth structures by preserving the demineralized enamel and dentin form cutting during cavity preparation.     

Spato-cognitive deficits in right parietal lesion and its impact on wayfinding: A case study

Abstract

A right-handed patient with a right parietal lesion has been Investigated in order to understand the impact of the lesion on spatial cognition and to understand the impact of spatio-cognitive deficits at the micro- and macro-scale on spatial orientation and wayfinding. Wayfinding abilities, in terms of decision making and information processing, were measured by the patient having to reach a destination in a complex hospital setting. The results showed that wayfinding was not affected by the lesion; no deficiencies were apparent in decision making and developing a plan of action nor were there any observable information treatment difficulties. The patient was also able to learn routes. He could choose the right route configuration at first sight, but could not distinguish the faulty drawing when he tried to reason his choice. The patient completed the pointing task without difficulties, but showed a significant impairment in all operations of a micro-spatial nature, in particular tasks requiring a mental rotation. The observation that the right parietal lesion had a marked impact on basic micro-spatial abilities, but no impact on the micro-scale, suggests a dissociation between these two spatio-cognitive functions. According to our data, wayfinding abilities do not seem to be affected by deficiencles at the micro-spatial level.