The effect of pre-vertebroplasty tumor ablation using laser-induced thermotherapy on biomechanical stability and cement fill in the metastatic spine

A biomechanical study comparing simulated lytic vertebral metastases treated with laser-induced thermotherapy (LITT) and vertebroplasty versus vertebroplasty alone. To investigate the effect of tumor ablation using LITT prior to vertebroplasty on biomechanical stability and cement fill patterns in a standardized model of spinal metastatic disease. Vertebroplasty in the metastatic spine is aimed at reducing pain, but is associated with risk of cement extravasation in up to 10%. Six pairs of fresh-frozen cadaveric thoracolumbar spinal motion segments were tested in axial compression intact, with simulated metastases and following percutaneous vertebroplasty with or without LITT. Canal narrowing under load, pattern of cement fill, load to failure, and LITT temperature and pressure generation were collected. In all LITT specimens, cement filled the defect without extravasation. The canal extravasation rate was 33% in specimens treated without LITT. LITT and vertebroplasty yielded a trend toward improved posterior wall stability (P = 0.095) as compared to vertebroplasty alone. Moderate rises in temperature and minimal pressure generation was seen during LITT. In this model, elimination of tumor by LITT, facilitates cement fill, enhances biomechanical stability and reduces the risk of cement extravasation.     

Alcohol and drug use following traumatic brain injury: A prospective study

Primary objectives: To establish pre-morbid alcohol and drug use in persons with TBI, relative to controls, investigate how patterns of substance use change over time following TBI and identify factors associated with heavy post-injury substance use.

Methods and procedures: The Alcohol Use Disorders Identification test (AUDIT) and Drug Abuse Screening Test (DAST) was completed by 121 hospital inpatients with TBI, documenting pre-injury alcohol and drug use, and 133 demographically similar controls. Participants with TBI completed these measures and the Hospital Anxiety and Depression Scale (HADS) again 1 and 2 years post-injury and 76 also completed them at 3 years.

Results: Participants with TBI showed similar levels of drug and alcohol use to controls pre-injury, with 31.4% of the TBI group and 29.3% of controls drinking at hazardous levels. Alcohol and drug use declined in the first year post-injury, but increased by 2 years post-injury, with only 21.4% of participants with TBI reporting abstinence from alcohol and 25.4% drinking at hazardous levels. Only 9% showed a drug problem, but 24% had returned to some drug use. Those showing heavy alcohol use post-injury were young, male and heavy drinkers pre-injury. Drug and alcohol use was similar at 3 years post-injury.

Conclusions: More active intervention is needed to reduce alcohol and drug use following TBI.     

Characteristics of calcaneal bone infarction: an MR imaging investigation

Objective. Bone infarction (BI) of the calcaneus is an uncommon entity which has received little mention in the recent literature. In this paper, we review the MR images of six calcanei with BI, which demonstrate a pattern of presentation that may explain the etiology of BI at this unusual location. Design. A retrospective review was performed of the transcribed reports of the foot or ankle MR examinations at our institution. MR images of examinations with any marrow signal abnormality were reviewed for presence of BI and its distribution. Patients. Based on MRI criteria, four patients had calcaneal BI (none biopsy proven); they ranged in age from 37 to 51 years old. Two patients were diagnosed with systemic lupus erythematosus, one with fibrositis, and another with polymyositis. All were treated with corticosteroids. Results. Six calcanei (in four patients) contained a region of calcaneal BI. In five of the six, the lesions were entirely or predominantly located in the posterior half of the calcaneus. Conclusion. Two theories are proposed which may explain why BI predominantly occurs in the posterior half of the calcaneus. First, the convergence of the recurrent intraosseous calcaneal vessels may occasionally produce the equivalent of a single dominant vessel that is more prone to vascular accidents. Secondly, the region between the recurrent and the epiphyseal vessels may act as a watershed zone, increasing its susceptibility to ischemia.     

Histomorphometric analysis of innervation of the anterior cruciate ligament in osteoarthritis

The aim of this study was to determine whether there are quantitative changes in the innervation of the anterior cruciate ligament in osteoarthritis. Eleven whole anterior cruciate ligaments were obtained at autopsy from cadavera of individuals with advanced osteoarthritis; five healthy ligaments were used as controls. The ligaments were transected and stained with hematoxylin and eosin, oil red O for fat, and a modification of Gairn's gold chloride method. The latter stain permits visualization of axons, mechanoreceptors, and free nerve endings that are not apparent on routine stains. The ratio of nerve tissue to periligamentous synovial tissue was determined histomorphometrically by the point-counting method. The nerve tissue was located almost exclusively in the periligamentous synovial tissue. There was a statistically significantly greater area of nerve tissue (as a percentage of the total area) around the anterior cruciate ligaments in the osteoarthritic group than around the ligaments in the control group (p < 0.02). The nerve tissue was distributed evenly throughout the periligamentous synovial tissue in the specimens in both groups. A neurological role has been proposed for the anterior cruciate ligament in osteoarthritis. This study provides morphological evidence for neural pathology of the anterior cruciate ligament in subjects with osteoarthritis.     

A new species of the genus Eudusbabekia (Acari: Prostigmata: myobiidae) on Leptonycteris nivalis (Chiroptera: Phyllostomidae) in central Mexico

Eudusbabekia provirilia new species was found on the bat Leptonycteris nivalis (Saussure) in the central part of Mexico. The female, male, protonymph, and larva are described and illustrated.     

Molecular physiology and pathophysiology of electroneutral cation-chloride cotransporters

Electroneutral cation-Cl^– cotransporters compose a family of solute carriers in which cation (Na⁺ or K⁺) movement through the plasma membrane is always accompanied by Cl^– in a 1:1 stoichiometry. Seven well-characterized members include one gene encoding the thiazide-sensitive Na⁺–Cl^– cotransporter, two genes encoding loop diuretic-sensitive Na⁺–K⁺–2Cl^– cotransporters, and four genes encoding K⁺–Cl^– cotransporters. These membrane proteins are involved in several physiological activities including transepithelial ion absorption and secretion, cell volume regulation, and setting intracellular Cl^– concentration below or above its electrochemical potential equilibrium. In addition, members of this family play an important role in cardiovascular and neuronal pharmacology and pathophysiology. Some of these cotransporters serve as targets for loop diuretics and thiazide-type diuretics, which are among the most commonly prescribed drugs in the world, and inactivating mutations of three members of the family cause inherited diseases such as Bartter's, Gitelman's, and Anderman's diseases. Major advances have been made in the past decade as consequences of molecular identification of all members in this family. This work is a comprehensive review of the knowledge that has evolved in this area and includes molecular biology of each gene, functional properties of identified cotransporters, structure-function relationships, and physiological and pathophysiological roles of each cotransporter.     

Ultrastructural analysis of hippocampal pyramidal neurons from apolipoprotein E-deficient mice treated with a cathepsin inhibitor

Cultured hippocampal slices prepared from apolipoprotein E (apoE)-deficient mice were exposed to an inhibitor of cathepsins B and L and then processed for an ultrastructural analysis of neuronal features for pyramidal cell bodies. Electron microscopy showed that the nuclei of pyramidal cells from treated hippocampal slices were more eccentrically located than those from untreated slices. In addition, increased numbers of vesicles were associated with the Golgi complex while microtubules were less frequent in the proximal dendrites. Consistent with previous studies in rats, treated apoE-deficient slices had increased numbers of lysosomes and multivesicular bodies. Finally, there were reductions in the number of synapses around the cell body, a finding similar to that found in the brains from Alzheimer's disease patients. These results provide ultrastructural data indicating that partial lysosomal dysfunction in apoE-deficient brains rapidly induces characteristic features of the aged human brain.     

Genetic imbalances in pleomorphic xanthoastrocytoma detected by comparative genomic hybridization and literature review.

Pleomorphic xanthoastrocytoma (PXA) is a rare, low-grade astrocytic tumor found in the central nervous system. Histologically, the tumor is characterized by markedly pleomorphic and lipidized cells. Although most of the patients have a favorable prognosis, a small number of cases undergoing recurrence or progression to anaplastic astrocytoma were reported. Very few genetic studies have been performed on PXA because of its rarity and the pathogenesis of this neoplasm is largely unknown. In order to provide an overview of genetic alterations in PXA, we performed comparative genomic hybridization to identify chromosomal imbalances (DNA gains and losses) in three cases of PXA. Genetic imbalance was detected on at least one chromosome for each case. One case, which revealed multiple genetic alterations, showed a poor prognosis. DNA gain on chromosome 7 and loss on 8p were demonstrated in two of three cases, suggesting that the candidate gene(s) located on these regions may play a role in the development of PXA. Further studies are needed to identify the residing candidate genes that are involved in the tumorigenesis of PXA. In addition, the histopathological features and previous genetic studies on PXA are reviewed.     

Plasma homocysteine concentration and its relationship with the development of preeclampsia. Effect of prenatal administration of folic acid

The increase of plasmatic homocysteine (Hc) in pregnant women, who later develop preeclampsia/eclampsia, the cause of this increment and its pathogenic role in toxemia of pregnancy, are still controversial. The objectives of the present research were to determine the plasmatic He concentrations during the first and second trimesters of pregnancy and the effect of folic acid administration on these values, and in the prevention of preeclampsia. Ninety six pregnant women of low economic background were studied on the first prenatal consultation: 27 women in the first trimester of pregnancy and 59 in the second. After 8 hours of fasting, venous blood was extracted and each patient was provided with 1 mg folic acid tablets and instructed to ingest one tablet daily, and to come back to the laboratory after three months. Plasma homocysteine and serum folic acid were determined for each patient before and after the folic acid treatment, by using the IMX system (Abbott Lab) and radioimmunoassay, respectively. Basal homocysteine concentrations were 4.0 +/- 2.1 micromol/L and 4.8 +/- 2.1 micromol/L in the first and second trimesters respectively, with no significant modifications after three months of folic acid. Although the degree of desertion from the study was high, it was possible to determine the evolution of 65 pregnancies. Ten of them developed preeclampsia (15.4%). No significant differences were found in Hc concentrations, or the frequency of hyperhomocysteinemia in the different stages of pregnancy, between women with normal gestation and those who developed preeclampsia. The small sample size of these groups, preclude any valid conclusion, however the results do not suggest that Hc concentration or folic acid administration influence the development of toxemia of pregnancy.