White matter hyperintensities and their association with suicidality in depressed young adults

INTRODUCTION: Researchers and clinicians have increasingly recognized that biological markers may help identify patients who are at risk for suicide. The objective of this retrospective, cross-sectional study was to compare the prevalence and location of white matter hyperintensities (WMH) in young inpatients with major depressive disorder (MDD) with and without histories of suicide attempts. METHODS: T2-weighted magnetic resonance images (MRI) of 102 young psychiatric inpatients with MDD were rated for the presence of WMH. Medical charts were reviewed to ascertain history of suicide attempt, demographic and clinical variables. Fisher's Exact Tests and logistic regression modeling were used to test the association between WMH and suicidality. RESULTS: Bivariate analysis showed that the prevalence of periventricular WMH was significantly higher in subjects with past suicide attempts (Fisher's Exact Test, p=0.02). Logistic regression analyses controlling for age, sex, and several clinical risk factors supported this finding (odds ratio=5.7; 95% confidence interval: 1.6, 21.2). LIMITATIONS: Due to the retrospective, cross-sectional design of our study, we are unable to determine if the WMH preceded or followed past suicide attempts. The generalizability of our findings is limited since this group of inpatients is more severely ill than the general psychiatric population. CONCLUSIONS: The increased prevalence of periventricular WMH in young adults with MDD and a history of suicide attempt, compared to similarly depressed adults without such a history, is consistent with our findings in children and youth, and suggests there might be neurobiological in addition to psychosocial risk factors for suicide.     

In vivo histologic and biomechanical characterization of a biodegradable particulate composite bone cement

A biodegradable particulate composite bone cement consisting of a crosslinked gelatin matrix and tricalcium phosphate particles was implanted intraosseously in rabbits for up to 12 weeks. Cured cylindrical implants were inserted in holes drilled in the proximal tibial metaphysis. Sequential fluorochrome labeling and radiographs were done, and specimens were processed for decalcified and nondecalcified histology. At 4 weeks, the cross-sectional diameter of the implant was slightly greater than at implantation. There was considerable dissolution of the matrix and some new bone ingrowth. At 12 weeks, the diameter was reduced to half the original diameter and bone had grown throughout the matrix. In the distal femur, freshly mixed cement was used to stabilize an osteochondral fracture. Mechanical testing of the cement-stabilized fracture revealed a decrease in compressive strength and modulus at 4 weeks followed by an increase to greater than initial values at 12 weeks. Over time, the osteochondral fragment subsided into the underlying cement, but the subsidence did not correlate with mechanical strength. This osteochondral fracture model permits measurement of the overall material properties of a cement simultaneously weakened by resorption and reinforced by ingrowing bone.     

Paramagnetic macrocyclic complexes as contrast agents for MR imaging: proton nuclear relaxation rate enhancement in aqueous solution and in rat tissues

Paramagnetic macrocyclic chelates show promise as magnetic resonance (MR) imaging contrast agents due to stability and relaxivity comparable to those of DTPA-type chelates. For the three copper and manganese macrocyclic complexes studied in aqueous solution, T1 and T2 relaxivities ranged from 0.14 to 5.88 mM-1sec-1 at 6.25 MHz. In rats, the intravenous administration of 16 mumol/kg of Mn(cyclam) caused the liver T1 relaxation rate to double at 15 minutes after injection. T1 measurements by pulsed MR imaging and manganese analyses on excised tissue showed that both relaxation rate (1/T1) and manganese content of liver and kidney increase linearly with the dosage of Mn(cyclam). The linear relationship between 1/T1 and manganese content can be considered an "in tissue" relaxivity plot for the agent. The resulting relaxivity is 54 mM-1sec-1 in liver, compared with 3.1 mM-1sec-1 in aqueous solution. Although this work is preliminary, the implication for medical MR imaging applications is that macrocyclic contrast agents can be effective at approximately one-tenth the current typical dose used for gadolinium DTPA.     

Abstracts from the Third Symposium of the Spanish Society of Bone and Mineral Research (SEIOMM) Oviedo,Spain 25–27 September 1991

Laboratory Investigations

Abstracts from the Third Symposium of the Spanish Society of Bone and Mineral Research (SEIOMM) Oviedo, Spain 25–27 September 1991     

Isochromosome 7q in adult Wilms' tumors: diagnostic and pathogenetic implications

Wilms' tumors affecting adults are rare and are thought to have a worse prognosis than similar stage tumors in the pediatric population. To understand these tumors better, the authors reviewed their multi-institutional experience in a series of nine lesions diagnosed as Wilms' tumors in adults. In addition to histologic and immunohistochemical examination, they performed cytogenetic analysis and fluorescence in situ hybridization. On review, four cases were reclassified: two "blastema only" as Ewing's sarcoma/primitive neuroectodermal tumor and the other two as clear cell sarcoma of soft parts and sarcoma not otherwise specified (NOS). Of the remaining five cases, three exhibited biphasic histology and two were triphasic. In this group, there were three women and two men, and patient age ranged from 17 to 37 years (median age, 26 years). Tumor size was large and ranged from 10 to 31 cm (median tumor size, 12.5 cm). Histologically, the tumors showed the typical features of Wilms' tumors with varying amounts of blastema (n = 5), epithelium (n = 5), and stroma (n = 2). No tumors contained anaplasia, and persistent renal blastema was not identified in the non-neoplastic kidney in any specimen. All tumors were positive for cytokeratins (CK7, n = 3; pankeratin, n = 5), and one tumor was weakly positive for CD99 (0-13). Molecular analysis including dual color fluorescence in situ hybridization (all tumors), and cytogenetic analysis (n = 2) disclosed the presence of isochromosome 7q in three of five tumors whereas all tumors were diploid with respect to chromosome 12. Follow-up data ranged from 6 to 133 months (median follow-up, 82 months) with progression in only one patient who had stage IV disease with lymph node and lung metastases at presentation. The authors conclude that adult Wilms' tumor has been overdiagnosed. Most "blastema-only" tumors in adults are not Wilms' tumors, and in an adult, biphasic morphology should be the minimum criteria for their diagnosis. Using strict diagnostic criteria, adult Wilms' tumors have a relatively favorable prognosis. The characteristic findings of isochromosome 7q, lack of trisomy or tetrasomy for chromosome 12, and absence of persistent renal blastema suggest that the pathogenesis of Wilms' tumors in adults may be different than in the pediatric population. These genetic features may be helpful in distinguishing adult Wilms' tumors from other primary renal tumors.     

Sex differences in response to red and blue light in human primary visual cortex: a bold fMRI study

Studies using a variety of investigative methods, including functional brain imaging and electroencephalography (EEG), have suggested that changes in central nervous system (CNS) dopamine function result in altered visual system processing. The discovery of abnormal retinal blue cone, but not red cone, electroretinogram in association with cocaine withdrawal and Parkinson's disease suggests that visual system response to blue light might be a marker for CNS dopamine tone. As there are numerous sex-related differences in central nervous system dopamine function, we predicted that blue and red light stimulation would produce sex-specific patterns of response in primary visual cortex when studied using the blood oxygen level dependent (BOLD) functional magnetic resonance imaging (fMRI) technique. We analyzed the BOLD response to red and blue light in male and female human volunteers (N=20). Red and blue light responses in primary visual cortex (V1) to stepped intensities of red and blue light were compared by sex for threshold to detectable BOLD signal increase and for stimulus intensity vs. BOLD signal response. Near threshold, males and females showed similar BOLD signal change to red light, but males showed a threefold greater increase (0.52%) to blue light stimulation when compared to females (0.14%). Log-linear regression modeling revealed that the slope coefficients for the red light stimulus intensity vs. signal change curve were not significantly different for males and females (z=0.995, P=0.320), whereas the slope coefficients for the blue light stimulus intensity vs. signal change curve were significantly larger in males (z=2.251, P=0.024). These findings support a sex and color-dependent differential pattern of primary visual cortical response to photic stimulation and suggest a method for assessing the influence of specific dopamine agonist/antagonist medications on visual function.