High-speed Si/GeSi hetero-structure Electro Absorption Modulator.

The ever-increasing demand for integrated, low power interconnect systems is pushing the bandwidth density of CMOS photonic devices. Taking advantage of the strong Franz-Keldysh effect in the C and L communication bands, electro-absorption modulators in Ge and GeSi are setting a new standard in terms of device footprint and power consumption for next generation photonics interconnect arrays. In this paper, we present a compact, low power electro-absorption modulator (EAM) Si/GeSi hetero-structure based on an 800 nm SOI overlayer with a modulation bandwidth of 56 GHz. The device design and fabrication tolerant process are presented, followed by the measurement analysis. Eye diagram measurements show a dynamic ER of 5.2 dB at a data rate of 56 Gb/s at 1566 nm, and calculated modulator power is 44 fJ/bit.

Split-mode fiber Bragg grating sensor for high-resolution static strain measurements.

We demonstrate a strain sensor with very high sensitivity in the static and low frequency regime based on a fiber ring cavity that includes a π phase-shifted fiber Bragg grating. The grating acts as a partial reflector that couples the two counter-propagating cavity modes, generating a splitting of the resonant frequencies. The presence of a sharp transition within the π phase-shifted fiber Bragg grating's spectral transmittance makes this frequency splitting extremely sensitive to length, temperature, and the refractive index of the fiber in the region where the grating is written. The splitting variations caused by small mechanical deformations of the grating are tracked in real time by interrogating a cavity resonance with a locked-carrier scanning-sideband technique. The measurable strain range and bandwidth are characterized, and a resolution of 320 pϵ/Hz(1/2) at 0 Hz is experimentally demonstrated, the highest achieved to date with a fiber Bragg grating sensor.

Pin1 contribution to Alzheimer's disease: transcriptional and epigenetic mechanisms in patients with late-onset Alzheimer's disease.

BACKGROUND: Neurofibrillary tangles and senile plaques are hallmarks of Alzheimer's disease (AD) although the molecular basis of their coexistence remains elusive. The peptidyl-prolyl cis/trans isomerase Pin1 acts on both tau and amyloid precursor protein to regulate their functions by influencing tau phosphorylation and amyloid precursor protein processing. OBJECTIVE: In order to identify potential biomarkers for AD in easily accessible cells and to gain insight into the relationship between the brain and peripheral compartments in AD pathology, we investigated Pin1 expression and activity in the peripheral blood mononuclear cells of subjects with late-onset AD (LOAD) and age-matched controls (CT). METHODS: Gene and protein expression, promoter methylation, Ser(16) phosphorylation and activity of Pin1 were evaluated in 32 samples from subjects with LOAD and in 28 samples from CT. RESULTS: In LOAD subjects, there was a statistically significant reduction in Ser(16) phosphorylation (-30%; p = 0.041) and promoter methylation (-8%; p = 0.001), whereas Pin1 expression was significantly increased (+74%; p = 0.018). CONCLUSION: The modifications of Pin1 found in LOAD subjects support its involvement in the pathogenesis of the disease with an important role being played by epigenetic mechanisms.

Pre-surgical planning and MR-tractography utility in brain tumour resection.

The purposes of this study were (1) to evaluate the possible identification of trajectories of fibre tracts, (2) to examine the useful of a neuronavigation system for presurgical planning, (3) to assess pre- and post-surgery patients' clinical condition and (4) to evaluate the impact of this information on surgical planning and procedure. Twenty-eight right-handed patients were prospectively and consecutively studied. All the patients were clinically assessed by a neurologist in both pre- and postsurgical phases. Separately the pyramidal tract, optic radiation and arcuate fasciculus were reconstructed. The trajectories were considered suitable for surgical planning if there were no interruptions of any of the layers at the level of the lesion. Dedicated software 'merged' the acquired images with the tractographic processing, and the whole dataset was sent to the neuronavigation system. The assessment of the 37 visualised trajectories close to the tumour resulted in a modification of the surgical approach to corticotomy in six patients (21%); the impact on the definition of the resection margins during surgery was 64%(18 cases). The overall impact percentage on the surgical procedure was 82%. In 27 cases, the symptoms had not changed. MR-tractography provides the neurosurgeon with a new anatomical view that has an impact on the surgical resection planning for brain neoplasms.

Análisis estadístico de la práctica quirúrgica oncológica de piel, en nuestra especialidad / Statistical analysis of skin cancer surgical practice in our specialty

El cáncer de piel es el más frecuente de todos los tipos de cáncer del ser humano, por lo cual el conocimiento y diagnóstico correcto de la patología oncocutánea, así como la formación impartida a los especialistas de nuestra área, es de vital importancia a la hora de jerarquizar el diagnóstico temprano y lograr un adecuado tratamiento de forma oportuna. El correcto abordaje terapéutico del cáncer cutáneo y sus variantes es de primordial importancia en el manejo quirúrgico de los cirujanos plásticos, por lo cual la Comisión de Oncología Quirúrgica de tumores de piel de la Sociedad Argentina de Cirugía Plástica Estética y Reparadora (SACPER) decide realizar y difundir la siguiente encuesta anónima a los miembros de la SACPER. En esta encuesta evaluativa, se obtuvieron datos sobre el estado actual de formación de los cirujanos de nuestro país, la ejecución de las prácticas relacionadas con el abordaje, la resección o la reconstrucción posterior relacionados a dicha patología.

The knowledge and correct diagnosis of the oncocutaneous pathology, as well as the training provided to the specialists in our area, is of vital importance when prioritizing early diagnosis and achieving adequate treatment. The correct therapeutic approach to skin cancer and its variants is of paramount importance in the surgical management of plastic surgeons, for which we decided to carry out an anonymous survey of the members of the Argentine Society of Aesthetic and Reconstructive Plastic Surgery (SACPER). In this questionnaire, we obtained valuable information about the current state of training of surgeons in our country, the execution of practices related to the approach, resection, or subsequent reconstruction related to said pathology.

Anterior clinoidal meningiomas: report of a series of 33 patients operated on through the pterional approach.

Between 1985 and 1995, 33 cases of clinoidal meningioma were surgically treated by pterional approach. In 6 cases, according to the grading scale of Al-Mefty, the lesions were group I, having originated from the lower part of the clinoid; in 22 cases, the lesions were group II, having originated from the upper or lateral part of the clinoid process; and in 5 cases, the lesions were group III since they arose from the optic foramen. Postoperatively, 17 patients showed an improvement, 4 were unchanged, and 6 presented further deficits. Five patients died after surgery: two from pulmonary thromboembolism, one from myocardial infarction, one from hematoma of the operative field, and one from cerebral ischemia after severe vasospasm of the internal carotid artery (unresponsive to treatment). The mean follow-up was 53.7 months (range 12-108 months) and included 19 patients. During this period, there were five recurrences, and three patients underwent resection again and showed no signs of tumor regrowth 1 year later; one patient who did not undergo resection again due to his age and poor general conditions died 3 years after onset of the recurrence; the last patient has so far refused a second operation. The clinical, diagnostic, and therapeutic aspects of this not infrequent pathology are discussed in the light of our experience and the pertinent literature.

Meningioma with meningioangiomatosis: a condition mimicking invasive meningiomas in children and young adults: report of two cases and review of the literature.

Meningioangiomatosis is a malformative meningovascular proliferation that occurs sporadically and in patients with neurofibromatosis type 2. Its histologic features of perivascular proliferation of elongated fibroblast and meningothelial cells trapping islands of gliotic cortex may be erroneously interpreted as invasion when an overlying meningioma is present. We report two cases of meningioangiomatosis associated with meningioma and review the literature on the subject for a total of six cases. The age of patients ranged from 9 months to 33 years. All cases were single lesions, and none had clinical evidence of neurofibromatosis type 2. Meningiomas in children have been regarded as having more aggressive behavior than their adult counterparts, with more frequent invasion of the underlying brain. The lack of correlation between brain invasion and recurrence observed in series of meningiomas in young patients may suggest that some of these lesions are meningioangiomatosis associated with meningioma rather than invasive meningiomas.

Lack of correlation between Ki-67 labelling index and tumor size of anterior pituitary adenomas.

AIMS AND BACKGROUND: The Ki-67 is a nuclear antigen detected by the monoclonal antibody MIB-1 and its Labeling Index (LI) is considered a marker of normal and abnormal cell proliferation. Pituitary adenomas are generally well differentiated neoplasms, even if in about one third of cases they are invasive of surrounding tissues. The aim of this study is to evaluate the correlation between Ki-67 labelling index and tumor size of pituitary adenomas extimated by means CT and MRI and confirmed at operation. METHODS: Using the monoclonal antibody MIB-1, we evaluated the expression of Ki-67 in 121 anterior pituitary adenomas consecutively operated on in a 48-month period. RESULTS: In relation to neuroradiological (CT and MRI) and surgically verified tumor size, we identified 24 microadenomas, 27 intrasellar macroadenomas, 34 intra-suprasellar macroadenomas, and 36 intra-supra-parasellar macroadenomas. The adenomas were non-infiltrating (76 cases) and infiltrating (45 cases) adenomas. The wall of the cavernous sinus (CS) was infiltrated in 18 cases. Forty-eight adenomas were non-functioning and 73 functioning. The overall mean +/- SD Ki-67 LI was 2.72 +/- 2.49% (median 1.6). It was 2.59 +/- 1.81 in microadenomas, 2.63 +/- 3.45 in intrasellar macroadenomas, 1.91 +/- 2.11 in intra-suprasellar macroadenomas, and 3.29 +/- 5.45 in intra-supra-parasellar macroadenomas (p = 0.27). It was 3.73 +/- 5.13% in infiltrating and 2.03 +/- 2.41% in non-infiltrating adenomas (p = 0.02), and 5.61 +/- 7.19% in CS-infiltrating versus 2.09 +/- 2.37% in CS-non-infiltrating adenomas (p = 0.0005). CONCLUSIONS: Our preliminary results seem to exclude significative correlations between Ki-67 LI and tumor size of anterior pituitary adenomas, even if this index can be considered a useful marker in the determination of the infiltrative behaviour of these tumors.

Ki-67 labelling index and invasiveness among anterior pituitary adenomas: analysis of 103 cases using the MIB-1 monoclonal antibody.

AIMS: To investigate the relation between proliferative activity of anterior pituitary adenomas, quantified by the Ki-67 labelling index, and their invasive behaviour. METHODS: Expression of Ki-67 was evaluated in 103 anterior pituitary adenomas consecutively operated on in a 36 month period and correlated with surgical evidence of invasiveness. RESULTS: Non-invasive (n = 65) and invasive (n = 38) adenomas were identified from surgically verified infiltration of sellar floor dura and bone. The wall of the cavernous sinus was infiltrated in 16 cases. Forty one adenomas were non-functioning and 62 functioning (24 prolactin, 21 growth hormone, 10 ACTH, seven mixed). The overall mean (SD) Ki-67 labelling index was 2.64 (3.69) per cent (median 1.5). The mean index was 3.08 (4.59) per cent in functioning and 1.97 (1.78) per cent in non-functioning tumours; 5.47 (9.52) per cent in ACTH adenomas and 2.33 (2.42) per cent in others (p = 0.01); 3.71 (5.17) per cent in invasive and 2.01 (2.45) per cent in non-invasive adenomas (p = 0.027); and 5.58 (7.24) per cent in cavernous sinus infiltrating v 2.10 (2.39) per cent in cavernous sinus non-infiltrating adenomas (p = 0.0005). To identify a value of labelling index beyond which adenomas should be considered invasive and another beyond which cavernous sinus infiltration should be suspected, normality Q-Q plots were obtained: a threshold labelling index of 3.5% for invasive adenomas and of 5% for cavernous sinus infiltrating adenomas was defined, with statistically significant differences (p = 0.02 and p = 0.004, respectively). CONCLUSIONS: The Ki-67 labelling index can be considered a useful marker in determining the invasive behaviour of anterior pituitary adenomas.

Tuberculoma of the ulnar nerve: case report.

A peripheral nerve tuberculoma, the third on record, involved the ulnar nerve, as did the other two. This case report is followed by a discussion of the pathogenesis and diagnosis of this lesion. Its pathogenesis is unclear. Direct infection from a tuberculous sister was disproved, and infection via a local wound is highly unlikely. A previous, silent form of tuberculosis seems to have been the cause.

Association between neuroepithelial tumor and multiple intestinal polyposis (Turcot's syndrome): report of a case and critical analysis of the literature.

We report a case of association of a brain tumor with multiple intestinal polyposis (Turcot's syndrome) and offer a critical analysis of the relevant literature with a view to revising the classification of the syndrome in relation to familial multiple polyposis and Gardner's syndrome. For this purpose, we considered only cases of intestinal polyposis associated with a primary neuroepithelial tumor (medulloblastoma, glioma, or glioblastoma) as originally described by Turcot. Differences emerged, depending on the central nervous system tumor type, which suggests that this neoplastic association may be classified as two distinct syndromes.

Aphasia in polyglots: report of two cases and analysis of the literature.

Two cases of aphasia in polyglot patients who experienced different symptoms in each of the languages they knew are reported. The authors discuss the problem and analyze the available literature in an attempt to formulate a pathogenetic hypothesis of the different involvement of the known idioms sometimes observed in aphasic polyglots. In particular, when time has elapsed between the learning of the mother tongue and other languages, and all the known languages are, consequently, functionally independent, it is possible that the two or more known idioms have distinct anatomical representations, probably localized separately in the two hemispheres. This could explain why, in some polyglots, aphasia affects one of the known languages preferentially. In subjects in whom the different known idioms were learned during early childhood, the anatomical representation of the languages is similar, which explains why, in this kind of polyglot, all the known languages can be equally affected by cerebral damage that causes aphasia.

Intradural extramedullary cavernous angioma: case report.

Cavernous angiomas represent 5 to 12% of spinal vascular malformations and usually are located at the vertebral body level with possible extension into the extradural space. The intradural intramedullary cavernoma occurs in about 3% of cases, whereas extramedullary localization is extremely rare. A new case of an intradural extramedullary cavernous angioma is reported, and the clinical, diagnostic, and therapeutic aspects of this rare malformation are analyzed.

Intracranial meningiomas in the 9th decade of life: a retrospective study of 17 surgical cases.

The general availability of cerebral computed tomographic and magnetic resonance imaging scans makes the observation of symptomatic intracranial meningiomas in very elderly patients (aged 80 yr or more) relatively frequent. A few authors have reported on patients who have undergone surgery for intracranial meningiomas in their 9th decade of life, without providing indications regarding the surgical criteria and the prognostic factors. We report on a series of 17 patients who have received surgery for intracranial meningiomas in their 9th decade of life, with the goal of determining some surgical criteria for general physicians and neurosurgeons. Patients with severe systemic disease and definite functional limitations (American Society of Anesthesiology Class III) had a major postoperative morbidity (P = 0.020) and mortality (P = 0.005), especially if they scored low (< 70) on the preoperative Karnofsky Rating Scale (P = 0.010). The risk of postoperative morbidity was higher when the maximum diameter of the tumor was > 5 cm (P = 0.031).

Mutism after posterior fossa surgery in children. Report of three cases.

Three patients aged 5 1/2 to 9 years old with mutism after posterior fossa surgery are presented. The entity is discussed with a review of 15 additional previously reported cases in children aged 2 to 11 years. In all 18 patients, a large midline tumor of the posterior fossa (medulloblastoma in nine cases, astrocytoma in five, and ependymoma in four), often attached to one or both lateral recesses of the fourth ventricle, was removed. Mutism developed 18 to 72 hours after the operation (mean 41.5 hours) in patients with no disturbance of consciousness and no deficits of the lower cranial nerves or of the organs of phonation. All of these children had spoken in the first hours after surgery. The disorder lasted from 3 to 16 weeks (mean 7.9 weeks). Speech was regained after a period of dysarthria in six of the 10 cases for whom this information was available. The various hypotheses advanced to explain the pathogenesis of this speech disorder are analyzed.

The long-term postoperative trinitroglycerin hypotension in normal perfusion pressure breakthrough syndrome.

The authors describe a case of normal perfusion pressure breakthrough syndrome, a catastrophic hemorrhage complicating surgery for cerebral arteriovenous malformations, due to chronic loss of autoregulation. Successful treatment was achieved with prolonged postoperative trinitroglycerin hypotension, associated with barbiturate-induced coma and artificial ventilation.

Proposal of a clinico-histological "glioma score" as a prognostic index in high-grade glioma patients. Preliminary observations in a series of 80 cases.

BACKGROUND: Despite of several multimodal treatments, malignant gliomas still have a poor outcome. In order to identify subgroups of patients with different prognosis, we propose a clinical and histological score (GS). METHODS: Eighty consecutive patients operated on for a high-grade glioma and treated with adjuvant therapy entered the study. In relation to age at diagnosis, preoperative Karnofsky Performance Status (KPS), and MIB-1 index, patients have been splitted in 4 groups (GS 0-III). RESULTS: The overall mean survival of the entire cohort was 18.2 months (median 12). Patients with GS 0 have a mean survival rate of 30.0 months, with GS I 23.1 months, with GS II 12.1 months, and with GS III 9.0 months (p=0.0001). Moreover, mean survival with a KPS = or >70 was 29.0 in GS 0, 26.0 in GS I, 10.0 in GS II, and 0 in GS III patients (p<0.0001). CONCLUSIONS: On the basis of these preliminary observations, we discuss the utility of our "glioma score" as a prognostic indicator for patients operated on for cerebral malignant gliomas and treated postoperatively with adjuvant therapy.

Recurrent cystic meningiomas. Report of two cases.

The Authors report 2 cases of recurrent cystic meningiomas among 22 cases operated on. After a review of the literature, the pathogenesis of the recurrences of these tumors is discussed, concluding that wrong interpretation of neuroradiological examination and/or incomplete extirpation of tumoral capsule are the main factors responsible of recurrences of cystic meningiomas.

Familial meningiomas. Report of two cases.

The Authors report a case of intracranial meningioma in two sisters, with no evidence of neurofibromatosis. A study of the karyotype has been performed; in one patient we have found a pericentric inversion of one chromosome 9. The possible role of the genetical factors in the develop of familial meningiomas is discussed.

Postoperative arachnoidal diverticula of the lumbar spine.

Arachnoidal diverticula are a rare complication of spinal surgery and occur most often at lumbar level, especially after discectomy. We report a case of lumbar arachnoidal diverticulum that arose two years after an L4-L5 discectomy and presented clinically with low back pain and sciatic pain and neurological deficits. We analyze the etiopathogenesis, clinical and radiological features and treatment.