The dose distribution of low dose rate Cs-137 in intracavitary brachytherapy: comparison of Monte Carlo simulation, treatment planning calculation and polymer gel measurement.

In this study, the dose distribution delivered by low dose rate Cs-137 brachytherapy sources was investigated using Monte Carlo (MC) techniques and polymer gel dosimetry. The results obtained were compared with a commercial treatment planning system (TPS). The 20 mm and the 30 mm diameter Selectron vaginal applicator set (Nucletron) were used for this study.

Efficacy of various drugs in the prevention of posterior capsule opacification: experimental study of rabbit eyes.

Purpose: To assess the efficacy of various drugs in the prevention of posterior capsule opacification (PCO) in a closed capsular bag technique.

Setting: Ophthalmic Biophysics Center, Bascom Palmer Eye Institute, University of Miami School of Medicine, Miami, Florida, USA.

Methods: Lens material was removed using phacoaspiration or phacoemulsification through a microcapsulorhexis according to the hardness of the crystalline lens correlated with the weight and age of the rabbits.

Transcellular thiocyanate transport by human airway epithelia.

Human airway mucosa synthesizes and secretes lactoperoxidase (LPO). As H(2)O(2) and thiocyanate (SCN(-)) are also present, a functional LPO antibacterial defence system exists in the airways. SCN(-) concentrations in several epithelial secretions are higher than in serum, although the mechanisms of transepithelial transport and accumulation in these secretions are unknown.

E-Cadherin (CDH1) and p53 rather than SMAD4 and Caspase-10 germline mutations contribute to genetic predisposition in Portuguese gastric cancer patients.

Approximately 30% of all hereditary diffuse gastric cancer (HDGC) families carry CDH1 germline mutations. The other two thirds remain genetically unexplained and are probably caused by alterations in other genes. Using polymerase chain reaction (PCR)/single-strand conformation polymorphism (SSCP)/sequencing, we screened 32 Portuguese families with a history of gastric cancer and 23 patients with early onset gastric cancer for CDH1 germline mutations.

Mutations in exon 14 of dihydropyrimidine dehydrogenase and 5-Fluorouracil toxicity in Portuguese colorectal cancer patients.

Purpose: Dihydropyrimidine dehydrogenase is a critical enzyme in the catabolism of 5-Fluorouracil, a drug frequently used in cancer therapy. Patients with deficient dihydropyrimidine dehydrogenase activity are at risk of developing severe 5-Fluorouracil-associated toxicity. Genetic analysis of the gene coding for dihydropyrimidine dehydrogenase has shown that mutations in exon 14, especially the splice-site mutation IVS14+1G-->A, were associated with dihydropyrimidine dehydrogenase enzymatic deficiency.

[Trigeminal sensory neuropathy and lupus anticoagulant positive: cause or coincidence?].

Introduction: Trigeminal sensory neuropathy (TSN) is a rare entity characterised by transient sensory disorders in one or more branches of the trigeminal nerve (TN). There are (acute or chronic) idiopathic forms as well as others that are linked to inflammatory, vascular or structural lesions.

Case Report: We describe the case of a female aged 30 who presented two self limited episodes of left facial hypaesthesia (second branch of the TN), with no other accompanying symptoms and which lasted 3 7 days, with complete resolution.

Incorporation of a combinatorial geometry package and improved scoring capabilities in the EGSnrc Monte Carlo Code system.

A description is given of a generic EGSnrc Monte Carlo user code, GenUC, which was developed as an attempt to simplify and optimize the geometry and scoring coding of EGSnrc user codes. GenUC was developed using the methodology of combinatorial geometry that allows a straightforward implementation of complicated geometric setups with intersecting boundaries, where subsequent modifications to the geometry are easily performed. Presently, GenUC has five elemental volumes that can be defined in any position in space: spheres, ellipsoids, parallelepipeds, and circular cylinders and cones.

Eye movement-related modulation of trigeminal neuron activity during active sleep and wakefulness.

The amplitude of electrically-evoked mass action potentials recorded in the spinal cord and brainstem has been reported to decrease only during eye movement events of active sleep. In contrast, we have reported that the response of trigeminal sensory neurons to peripheral stimuli is modulated throughout the behavioral state of active sleep. It is unclear whether eye movement events contribute to the modulation of trigeminal sensory neuron activity during active sleep.

Cushing's syndrome secondary to adrenocorticotropin-independent macronodular adrenocortical hyperplasia due to activating mutations of GNAS1 gene.

ACTH-independent macronodular adrenal hyperplasia (AIMAH) is an uncommon cause of Cushing's syndrome characterized by bilateral nodular adrenocortical hyperfunction in the presence of suppressed ACTH levels. We investigated whether activating mutations in the ACTH receptor (MC2-R) or G(s alpha) (GNAS1) genes might be involved in AIMAH genesis. Five women with Cushing's syndrome due to AIMAH, confirmed by histological studies, and no signs of McCune-Albright syndrome were selected for molecular analysis of these genes.

Transmission through the dorsal spinocerebellar and spinoreticular tracts: wakefulness versus thiopental anesthesia.

Background: Most of what is known regarding the actions of injectable barbiturate anesthetics on the activity of lumbar sensory neurons arises from experiments performed in acute animal preparations that are exposed to invasive surgery and neural depression caused by coadministered inhalational anesthetics. Other parameters such as cortical synchronization and motor ouflow are typically not monitored, and, therefore, anesthetic actions on multiple cellular systems have not been quantitatively compared.

Methods: The activities of antidromically identified dorsal spinocerebellar and spinoreticular tract neurons, neck motoneurons, and cortical neurons were monitored extracellularly before, during, and following recovery from the anesthetic state induced by thiopental in intact, chronically instrumented animal preparations.

Detection of gsp somatic mutation through direct sequencing of heteroduplex alleles disclosed by denaturing gradient gel electrophoresis.

Background: The identification of somatic mutations in tissues is often difficult when the number of normal alleles in the tissue far exceeds the number of mutant ones. We found that the identification of gsp mutation was not possible by direct sequencing and present a new approach that improves the identification of gsp somatic mutations.

Material/methods: Genomic DNA was extracted from frozen tissue of a human ovarian stromal Leydig cell tumor.

An inherited mutation outside the highly conserved DNA-binding domain of the p53 tumor suppressor protein in children and adults with sporadic adrenocortical tumors.

Mutations of the p53 tumor suppressor gene are the single most common genetic alterations in human cancers. Recently, a distinct nucleotide substitution was identified in exon 10 of the p53 gene, leading to an Arg337His mutation in 97% of children with adrenocortical tumors from Southern Brazil. In the present study, we investigated the presence of this mutation in a larger series of 55 patients (37 adults and 18 children) with benign and malignant sporadic adrenocortical tumors.

A general method for estimating deformation and forces imposed in vivo on bioprosthetic heart valves with flexible annuli: in vitro and animal validation studies.

Background And Aim Of The Study: The use of flexible structures within cardiovascular prostheses such as valves, stents and vascular grafts has been proposed as a means of more closely modeling native mechanics, and thereby reducing the biomechanical problems associated with rigid materials. However, the design of such materials has been hampered by the paucity of quantitative information on the in-vivo behavior of such structures. The aim of this study was to explore the use of 3D ultrasound imaging coupled with finite element analysis (FEA) as a tool to estimate deformation and forces imposed in vivo on a novel bioprosthetic valve design.

Axonal regeneration into Schwann cell grafts within resorbable poly(alpha-hydroxyacid) guidance channels in the adult rat spinal cord.

Axonal growth and myelination in a SC graft contained in a resorbable tubular scaffold made of poly(D,L-lactic acid) (PLA50) or high molecular weight poly(L-lactic acid) mixed with 10% poly(L-lactic acid) oligomers (PLA(100/10)) were studied for up to 4 months after implantation in the completely transected adult rat thoracic spinal cord. The PLA50 tubes collapsed soon after implantation and, consequently, compressed the graft inside, leading to only occasional thin cables with SCs and a low number of myelinated axons: 17 +/- 6 at 1 and 158 +/- 11 at 2 months post-grafting. The cable contained 32 +/- 23 blood vessels at 2 weeks, 55 +/- 33 at 1 month and 46 +/- 30 at 2 months after implantation.

No evidence of somatic activating mutations on gonadotropin receptor genes in sex cord stromal tumors.

Objective: To search for somatic activating mutations of gonadotropin receptor (FSH-R and LH/chorionic gonadotropin receptor [CG-R]) genes as a cause of sex cord stromal tumors.

Design: Molecular studies in human tissue.

Setting: University hospital.

[Essential mixed cryoglobulinemia as a cause of ischemic cerebrovascular accident].

Introduction: Involvement of the central nervous system in patients with essential mixed cryoglobulinaemia is rare, and there are few cases described in the medical literature. Moreover, the mechanism by which lesions are produced in the central nervous system is still not clear.

Clinical Case: We describe the case of a 35 year old woman who presented with dysarthria, weakness and paraesthesia of her left limbs and left central facial paralysis of sudden onset.

[Transient global amnesia and vascular risk factors].

Introduction: Transient global amnesia (TGA) is a clinical syndrome determined by an episode of less than 24 hours consisting of temporo-spatial disorientation with retrograde and anterograde amnesia followed by complete recovery.

Objectives: To determine whether the presence or absence of vascular risk factors (VRF) in patients with TGA is associated with different clinical data and/or examination findings.

Patients And Methods: A retrospective study was made of two groups of 13 and 12 patients with TGA, who presented with and without VRF, respectively.

Origin of an ovarian steroid cell tumor causing isosexual pseudoprecocious puberty demonstrated by the expression of adrenal steroidogenic enzymes and adrenocorticotropin receptor.

Ovarian steroid cell tumors are rare neoplasms composed of typical steroid hormone-secreting cells. Most ovarian steroid cell tumors, however, cannot be appropriately classified on a morphological basis, because the neoplastic cells closely resemble adrenal cortical cells. Nevertheless, the true adrenal origin of such tumors has been difficult to demonstrate.

Mutation analysis of the follicle-stimulating hormone receptor gene in girls with gonadotropin-independent precocious puberty resulting from autonomous cystic ovaries.

Objective: To search for germline activating mutations of the FSH receptor in girls with gonadotropin-independent precocious puberty.

Design: Molecular studies in human tissue.

Setting: Four girls with polycystic ovaries and gonadotropin-independent isosexual precocious puberty without clinical and molecular features of McCune-Albright syndrome.

Tooth pulp- and facial hair mechanoreceptor-evoked responses of trigeminal sensory neurons are attenuated during ketamine anesthesia.

Background: Evidence exists that ketamine, administered systemically using a dose required for inducing a state of anesthesia, may antagonize nociceptive but not innocuous input to lumbar dorsal horn neurons. However, it is unclear whether ketamine exerts this selective action on sensory inputs to trigeminal sensory neurons. The current study was undertaken to compare the responses evoked in trigeminal sensory neurons by electrical stimuli applied to the tooth pulp versus air-puff stimuli applied to facial hair mechanoreceptors (FHMs) during quiet wakefulness versus ketamine anesthesia.

Treatment of gonadotropin dependent precocious puberty due to hypothalamic hamartoma with gonadotropin releasing hormone agonist depot.

The gonadotropin releasing hormone (GnRH) secreting hypothalamic hamartoma (HH) is a congenital malformation consisting of a heterotopic mass of nervous tissue that contains GnRH neurosecretory neurons attached to the tuber cinereum or the floor of the third ventricle. HH is a well recognised cause of gonadotropin dependent precocious puberty (GDPP). Long term data are presented on eight children (five boys and three girls) with GDPP due to HH.

Effects of an anti-exospore monoclonal antibody on microsporidial development in vitro.

In this study we evaluated the effects of the anti-microsporidial exospore monoclonal antibody 3B6, recognizing 3 Encephalitozoon species, Encephalitozoon intestinalis (Syn. Septata intestinalis), Encephalitozoon cuniculi, and Encephalitozoon hellem on microsporidial growth in vitro. Pre-treatment of spores for 24 h with mAb 3B6 resulted in 21-29% fewer infected host cells 4 days after inoculation of the cultures compared to cultures pre-treated with medium or an irrelevant isotype control mAb (P < 0.

Poly(alpha-hydroxyacids) for application in the spinal cord: resorbability and biocompatibility with adult rat Schwann cells and spinal cord.

Future surgical strategies to restore neurological function in the damaged human spinal cord may involve replacement of nerve tissue with cultured Schwann cells using biodegradable guiding implants. We have studied the in vitro and in vivo degradability of various aliphatic polyesters as well as their effects on rat Schwann cells in vitro and on spinal cord tissue in vivo. In vitro, cylinders made of poly(D,L-lactic-co-glycolic acid) 50:50 (PLA25GA50) started to degrade at 7 days, compared with 28 days for cylinders made of poly(D,L-lactic acid) (PLA50).

Activating mutation of the stimulatory G protein (gsp) as a putative cause of ovarian and testicular human stromal Leydig cell tumors.

Activating mutations of the G protein genes have been associated with the development of several endocrine neoplasms. Such activating mutations, gip2, affecting the alpha-subunit of the G alpha i2 protein were previously described by a single group in 30% of ovarian sex cord stromal tumors. Other activating mutations of the alpha-subunit of the Gs (gsp) have been identified in GH-secreting and nonfunctioning pituitary tumors, autonomous thyroid adenomas, and all affected McCune-Albright tissues, but not in sex cord stromal tumors.