Gulliver's virtual travels: active embodiment in extreme body sizes for modulating our body representations.

It is noted that the perceptual experience of body and space can be modulated by changing the action capabilities or by manipulating the perceived body dimensions through a multisensory stimulation. This study adds to pre-existing literature by investigating the alterations in bodily experience following embodiment to both enlarged and shrunked bodies, while participants actively navigated in a virtual environment. A normal-sized body served as a reference condition. After each embodied navigation, participants estimated the height and width of three different body parts. Results revealed that the embodiment over shrunked body induced a significant reduction in participants' body image, while no changes were reported after the embodiment over the enlarged body. Findings were discussed in terms of previous literature exploring the constraints implicated in the ownership over different bodies.

A juvenile case of cerebellar arteriovenous malformation with gradual onset of dysphoria and headache.

A 25-year-old woman was admitted because of frequent vomiting and headache which had lasted over one week. She had initially clear consciousness but slowly progressive mild headache and dysphoria. Emergency cranial CT revealed a 4 cm haematoma in the left cerebellar hemisphere. CT angiography showed a 2×2 cm nidus of an arteriovenous malformation (AVM) in the left hemisphere fed from the left posterior inferior cerebellar artery and draining into the inferior hemispheric vein. We performed a surgical resection of the AVM after decompression therapy to counteract the brain oedema. She recovered completely without any neurological deficits. This case recalls the importance of cooperation between diagnostic neuroradiology and neurosurgery in emergency, considering AVM, even if infrequent, among possible diseases.

Cerebral blood flow autoregulation during intracranial hypertension: a simple, purely hydraulic mechanism?

OBJECTIVE: In this paper, we re-propose the role of a hydraulic mechanism, acting where the bridging veins enter the dural sinuses in cerebral blood flow (CBF) autoregulation. MATERIALS AND METHODS: We carried out an intraventricular infusion in ten albino rabbits and increased intracranial pressure (ICP) up to arterial blood pressure (ABP) levels. We measured CBF velocity by an ultrasound probe applied to a by-pass inserted in a carotid artery and recorded ICP by an intraventricular needle. Diastolic and pulsatile ICP and ABP values were analyzed from basal conditions up to brain tamponade and vice versa. CONCLUSIONS: A biphasic pattern of pulsatile intracranial pressure (pICP) was observed in all trials. Initially, until the CBF velocity remained constant, pICP increased (from 1.2 to 5.4 mmHg) following a rise in diastolic intracranial pressure (dICP); thereafter, in spite of a further rise in dICP, pICP decreased (2.87 mmHg) following CBF velocity reduction until intracranial circulation arrest (pICP=1.2 mmHg). A specular pattern was observed when the intraventricular infusion was stopped and CBF velocity returned to basal levels. These findings can be interpreted as indicating a hydraulic mechanism. Initially, when CBF is still constant, pICP rise is due to an increase in venous outflow resistance; subsequently, when CBF decreases following a further increase in venous outflow resistance, the vascular engorgement produces an arteriolar vasodilation. This vasodilation determines an increase in vascular wall stiffness, thus reducing pulse transmission to surrounding subarachnoid spaces.

Abdominal aortic aneurysm in renal transplant recipients.

BACKGROUND: Abdominal aortic aneurysms (AAA) requiring surgical management are encountered more frequently in renal transplant recipients, presenting an important technical problem during the repair. The aim of the present study was to analyze the epidemiology and natural evolution of AAA among renal allograft recipients. METHODS: Three hundred ninety-four renal transplant recipients were periodically evaluated with abdominal aortic ultrasound tomography for AAA. The indication for surgery was a maximal diameter >5 cm. Renal function, graft, and patient survival were evaluated after a mean follow-up of 51 months. RESULTS: Four AAA were detected in 394 renal transplant recipients, a prevalence of 1.01%. All of the AAA were found in male recipients of mean age 59.2 +/- 5.5 years and mean time posttransplantation of 82.7 +/- 77.3 months. The mean follow-up period between diagnosis and indication for surgery was 14.2 +/- 10.8 months. Two patients underwent open repair with aneurysmectomy and conventional tube graft positioning, and 2 patients refused surgical repair. To preserve renal graft function during the aortic cross-clamping phase, cold perfusion with 4 degrees C Ringer acetate and local hypothermia with sterile ice were used. Renal function did not change after the operation (preoperative serum creatinine levels were 1.2 and 1.3 mg/dL; postoperative 1.3 and 1.5 mg/dL respectively). The 2 patients who underwent surgery are alive with excellent graft functioning after a follow-up of 1.5 and 7 years, respectively. The 2 patients who refused surgical treatment are dead. CONCLUSIONS: Yearly ultrasound screening for AAA must be recommended in renal transplant recipients as part of the routine posttransplantation follow-up. De novo AAA occurs in younger subject in the transplant population and shows a faster evolution.

Prediction of 6-month survival after liver transplantation using Cox regression.

BACKGROUND: The outcome of liver transplantation (LTx) has been correlated with several donor and recipient factors. METHODS: A database of 191 consecutive LTx cases was analyzed using Kaplan-Meier and Cox regression statistics based on 80 variables. To avoid additional effects of late events on patient survival, the chosen endpoint was 6 months. Data were evaluated using SPSS statistical software. RESULTS: Kaplan-Meier analysis revealed a difference in 1- to 6-month graft survival between patients transplanted with organs from donors older versus younger than 60 years (Breslow, P <.01). Differences in 1- to 6-month graft survivals were observed between patients listed as UNOS status 3, 2B, 2A, and 1: the outcomes for UNOS status 2B versus UNOS status 2A and UNOS status 2B versus status 1 were significant (P <.05). Differences in 1- to 6-month graft survival rates were found between patients with versus without sepsis (P <.05), and with versus without rejection episodes (P <.01). Cox regression analysis revealed only three of the variables to be independent prognostic predictors of graft failure: donor age; postoperative septic status; and rejection. The best mathematical multivariate Cox regression model linked donor age + donor Na + rejection + sepsis to 1- to 6-month graft survival (chi-square = 29.06, P <.001). CONCLUSION: Factors predictive of 1- to 6-month graft survival after liver transplantation include donor age; UNOS status; sepsis; and rejection.

Spontaneous regression of a symptomatic pineal cyst after endoscopic third-ventriculostomy.

With the advent of modern diagnostic tools for neuroimaging, the incidental detection of pineal cysts in asymptomatic subjects has increased. Only rarely do pineal cysts present with the clinical signs and symptoms of increased intracranial pressure or with neurological deficits in relation to compression and distortion of the adjacent nervous structures and cerebrospinal fluid pathways. While asymptomatic cysts are considered to be normal variants for which no further investigations are usually required, surgical treatment is suggested for symptomatic cysts, with the goal of eliminating the block in the cerebrospinal fluid circulation and/or the mass effect exerted by the lesion. In this report we describe a pediatric case of symptomatic pineal cyst, revealed by repeated episodes of headache caused by secondary obstructive hydrocephalus. Following an endoscopic third-ventriculostomy, serial magnetic resonance imaging studies demonstrated that not only had the ventriculomegaly resolved but also that the pineal cyst had regressed over time. A to-and-fro movement of fluid through the cyst wall, the direction of which depends on the equilibrium existing between the inner pressure of the cyst and the outer cerebrospinal fluid pressure, is suggested as a possible mechanism accounting for this unexpected result--to our knowledge, the first reported in literature.

Blood salvage in craniosynostosis surgery.

In the history of surgery, every single step forward in the development of complex surgical techniques has been sustained by the acquisition of more reliable and effective methods for controlling hemostasis. For many years, in fact, uncontrolled hemorrhages, together with infections, represented the most deadly hazard of surgical procedures. In the last century, technical advances in surgical hardware and homologous blood transfusions have been utilized to counteract operative and postoperative anemia and hypovolemia. At the end of this millennium, however, new revelations about the infective and noninfective risks of allogeneic blood transfusions have led to a new acceleration in patients' and physicians' demands for autologous transfusions and more efficient blood conservation techniques. Specific surgical protocols, based on the preoperative administration of r-HuEPO, preoperative autologous blood donation, acute preoperative normovolemic hemodilution and intraoperative blood salvage techniques, have been designed by pediatric neurosurgeons to minimize the exposure of patients affected by craniosynostoses to allogeneic blood and blood components even when the surgical procedure is to be realized at an early age. In spite of the evolution expected in this area in the immediate future, the implementation of these blood concentration methodologies may prove to be highly effective only when associated with a concerned attitude of the surgeon toward blood-sparing intraoperative strategies.

Nucleotide substitution rate of mammalian mitochondrial genomes.

We present here for the first time a comprehensive study based on the analysis of closely related organisms to provide an accurate determination of the nucleotide substitution rate in mammalian mitochondrial genomes. This study examines the evolutionary pattern of the different functional mtDNA regions as accurately as possible on the grounds of available data, revealing some important "genomic laws." The main conclusions can be summarized as follows. (1) High intragenomic variability in the evolutionary dynamic of mtDNA was found. The substitution rate is strongly dependent on the region considered, and slow- and fast-evolving regions can be identified. Nonsynonymous sites, the D-loop central domain, and tRNA and rRNA genes evolve much more slowly than synonymous sites and the two peripheral D-loop region domains. The synonymous rate is fairly uniform over the genome, whereas the rate of nonsynonymous sites depends on functional constraints and therefore differs considerably between genes. (2) The commonly accepted statement that mtDNA evolves more rapidly than nuclear DNA is valid only for some regions, thus it should be referred to specific mitochondrial components. In particular, nonsynonymous sites show comparable rates in mitochondrial and nuclear genes; synonymous sites and small rRNA evolve about 20 times more rapidly and tRNAs about 100 times more rapidly in mitochondria than in their nuclear counterpart. (3) A species-specific evolution is particularly evident in the D-loop region. As the divergence times of the organism pairs under consideration are known with sufficient accuracy, absolute nucleotide substitution rates are also provided.

Perfil demográfico, morbilidad y mortalidad en internados por el servicio de emergencias del Hospital de Clínicas, 1997 / Demographic profile, morbity and moratality in hospitalized patients by emergency unit of Clinical Hospital, 1997

Estudio descriptivo y analítico, realizado a partir de las fichas de ingreso de pacientes al Servicio de Emergencias del Hospital de Clínicas, registradas durante el año 1997 y su posterior seguimiento hasta el egreso de los mismos, en el SE fueron asistidos 14.463, los diagnósticos fueron agrupados según clasificación utilizada en CIE-10

Preoperative recipient data and immunosuppression levels are predictive of early patient survival after liver transplantation.

The role of donor, preoperative, intraoperative, and postoperative factors in predicting patient survival after liver transplantation was evaluated by the Bio Medicus data package on a database containing 162 variables filled with records from 100 consecutive first-liver transplant cases. Donor data did not predict outcome. Recipient preoperative data (Child status, HCV status) were predictive using life table and Cox regression methods. Recipient intraoperative data (by-pass time, warm ischemia time, delay in arterial revascularization, and packed red blood cell requirements) were predictive of outcome using life table analysis. Recipient post-operative data (rejection, sepsis, primary dysfunction, and hepatic artery thrombosis) were predictive of outcome.

"No allogeneic blood transfusion" protocol for the surgical correction of craniosynostoses. II. Clinical application.

The authors describe the results obtained in 13 consecutive cases of craniosynostosis operated on according to a protocol devised at avoiding allogeneic blood transfusion. The protocol is based on pre- and postoperative treatment with erythropoietin, preoperative autologous blood donation, preoperative normovolemic hemodilution and intraoperative blood salvage. Nine subjects were affected by simple forms of craniosynostosis, whereas the remaining 4 presented with oxycephaly or craniofacial syndromes. Five of the 13 children were under 7 months and a further 3, under 10 months of age at the time of the surgical operation. Seven children weighed less than 10 kg. Allogeneic blood transfusion was avoided in 11 of the 13 children considered. Two failures - defined as the necessity to reinfuse the patient with an allogeneic blood transfusion - were recorded, 1 of them resulting from an unexpected hemorrhage during surgery. The results obtained indicate that this protocol designed to avoid allogeneic blood transfusion can be safely applied in the great majority of children with craniosynostosis, even when the surgical correction is carried out early in life.

"No allogeneic blood transfusion" protocol for the surgical correction of craniosynostoses. I. Rationale.

Improved anesthesiological and surgical care has resulted in a progressively declining need for allogeneic blood transfusion. In infants with craniosynostosis, however, allogeneic blood transfusion is still performed as a routine procedure. In the present paper, the authors describe a protocol they have devised with the aim of limiting or even avoiding allogeneic blood transfusion even in very young patients, consequently avoiding the risks of infective or immunologic reactions associated with the procedure. The protocol is based on stimulation of the hematopoietic system with erythropoietin, selection of an appropriate age for operation when a favorable balance between fetal and adult-type hemoglobin is established (that is after 4-6 months), preoperative preparation of the autologous blood supply, and intraoperative blood salvage.

[Recurrent biliary calculi]. / La calcolosi biliare plurirecidiva.

The Authors report two cases of recurrent bile duct stones and discuss about the diagnosis and treatment of this infrequent disease. Although diagnostic and management procedures are similar to those commonly used in all types of biliary stones, therapeutical options may be different in relation to the different clinical pictures. The Authors strongly suggest that bilioenteric anastomosis and endoscopic sphincterotomy are the best procedures to assure a correct and definitive treatment of recurrent biliary stones. However, the adoption of different diagnostic and therapeutic approaches, rather than univocal schemes, is recommended.

[Rational and mini-invasive approach to the therapy in varicose syndrome: the C.H.I.V.A. treatment]. / Approccio razionale e mininvasivo alla terapia della sindrome varicosa: la cura C.H.I.V.A.

The principles of the C.H.I.V.A. (Ambulatory conservative and haemodynamic therapy of venous insufficiency) procedure are reported. According to the Authors a careful haemodynamic evaluation of the venous system strictly correlates to the clinical and functional results. In their experience, in fact, results showed no variceal recurrence and a very low rate of complications. Therefore, the C.H.I.V.A. procedure is recommended for most of the patients with lower limb varices.