The role of cell surface proteins in platelet stimulation by monosodium urate crystals

To test whether urate crystal-membrane protein interactions mediate platelet stimulation, platelet membrane proteins were radiolabeled by lactoperoxidase, extracted with 1% Triton X–100, and incubated with urate crystals. The crystal-associated and supernate fractions were isolated and analyzed by sodium dodecyl sulfate–polyacrylamide gel electrophoresis (SDS–PAGE) and by 2-dimensional isoelectric focusing followed by SDS-PAGE. Four of the lactoperoxidaseradiolabeled polypeptides that associated with urate crystals had reduced molecular weights and pIs of M_r = 105,000, pI 4.9; M_r = 123,000, pI = 4.9; M_r = 123,000, pI = 5.3; and M_r = 132,000, pI = 4.8–6.3, respectively. These proteins were characterized with regard to their labeling intensities, apparent isoelectric points, apparent molecular weights (reduced and nonreduced), lectin-binding properties, carbohydrate- and protein-staining characteristics, and presence or absence in Glanzmann's thrombasthenia. They have been identified as derived from glycoproteins Ib, IIb, and III (Phillips-Agin nomenclature) and an unidentified membrane protein. To test whether removal of these proteins would result in a diminution of platelet response to urate, intact platelets were digested with chymotrypsin, resulting in cleavage of more than 80% of these proteins and a 5-fold reduction in secretory responsiveness to urate crystals. Response to a second platelet stimulus, collagen, was unaffected, indicating an intact secretory mechanism. In addition, when platelets were preincubated with F(ab′)₂ fragments of an antibody directed against these proteins, platelet secretory response to urate was inhibited by 50%, whereas the responses to collagen and thrombin were unaffected. Thus, membrane proteins appear to mediate platelet stimulation by urate crystals.     

Alcoholic organic brain disease: nosology and pathophysiologic mechanisms

Study of alcoholic chronic organic brain syndrome may have applicability to the large population of alcoholics with less severe cerebral dysfunction. Brain impairment in alcoholics may be conceptualized as two clinically and neuropathologically distinguishable organic brain syndromes: alcohol amnestic disorder or Korsakoff's psychosis (KP) and alcoholic dementia. Alcoholic organic brain disease may result from two interacting pathophysiological processes: nutritional (thiamine) deficiency and ethanol neurotoxicity. Subcortical periventricular lesions associated with KP result primarily from thiamine deficiency, whereas ethanol neurotoxicity and various secondary effects of alcoholism may contribute to the cortical neuropathological changes associated with alcoholic dementia. These two patterns of brain damage may be differentiable in individual alcoholics using cognitive tests and other measures of CNS function and, therefore, allow selection of a treatment strategy based on pathophysiological considerations. Studies in animals and humans suggest that a genetic predisposition to thiamine deficiency may contribute to alcoholism-associated dysfunction of brain and other organ systems and possibly have a causative role in the development of alcoholism.     

Intensive chemotherapy in aggressive lymphomas: updated results of LNH- 80 protocol and prognostic factors affecting response and survival

One hundred patients with aggressive malignant lymphomas treated with the LNH-80 regimen were evaluated for long-term survival and pretreatment characteristics predictive of response and survival. LNH- 80 consists of three intensive courses of adriamycin cyclophosphamide vindesine bleomycin (ACVB) followed by sequential consolidation and final intensification. Eighty-four patients went into complete remission (CR), eight had a partial response (PR), three failed to respond, and five died during induction. Twenty-three patients (27%) relapsed, in two of whom a prolonged second remission was obtained. Sixty-three patients are currently alive, two of them with disease. Four patients died in CR. Median survival and median freedom from relapse survival were not reached with a median follow-up of 4 1/2 years. Characteristics negatively associated with response in multivariate analysis were: poor performance status, bone marrow involvement, and two or more extranodal sites of disease. Duration of CR was associated with splenic involvement. Three characteristics were negatively associated with survival in multivariate analysis: age, high grade subtypes, and bone marrow involvement.     

CD200 is a novel p53-target gene involved in apoptosis-associated immune tolerance

During apoptotic cell death, biochemical processes modify self-proteins and create potential autoantigens. To maintain self-tolerance in the face of natural cell turnover, the immune system must prevent or control responses to apoptosis-associated autoantigens or risk autoimmunity. The molecular mechanisms governing this process remain largely unknown. Here, we show that expression of the immunoregulatory protein CD200 increases as murine dendritic cells (DCs) undergo apoptosis. We define CD200 as a p53-target gene and identify both p53- and caspase-dependent pathways that control CD200 expression during apoptosis. CD200 expression on apoptotic DCs diminishes proinflammatory cytokine production in response to self-antigens in vitro and is required for UVB-mediated tolerance to haptenated self-proteins in vivo. Up-regulation of CD200 may represent a novel mechanism, whereby immune reactivity to apoptosis-associated self-antigens is suppressed under steady state conditions.     

Long-Term Therapy With Benzodiazepines Despite Alcohol Dependence Disorder

The author describes the long-term administration of benzodiazepines to seven male patients (58–70 years old), each with at least a 25-year history of alcohol dependence. Benzodiazepines were prescribed for the treatment of an anxiety disorder or sleep disturbance. All seven patients maintained abstinence during benzodiazepine administration, except for a brief period of relapse in two patients. These patients comprised all of the subjects given benzodiazepines for more than 1 week in a Veterans Affairs substance abuse program over a 3-year period. These case reports suggest that the long-term administration of benzodiazepines to carefully selected alcohol-dependent patients is not necessarily incompatible with abstinence. Guidelines for the use of benzodiazepines in this patient population are reviewed.     

Renoprotection From Diabetic Complications in OVE Transgenic Mice by Endothelial Cell Specific Overexpression of Metallothionein: A TEM Stereological Analysis

We previously demonstrated that OVE transgenic diabetic mice are susceptible to chronic complications of diabetic nephropathy (DN) including substantial oxidative damage to the renal glomerular filtration barrier (GFB). Importantly, the damage was mitigated significantly by overexpression of the powerful antioxidant, metallothionein (MT) in podocytes. To test our hypothesis that GFB damage in OVE mice is the result of endothelial oxidative insult, a new JTMT transgenic mouse was designed in which MT overexpression was targeted specifically to endothelial cells. At 60 days of age, JTMT mice were crossed with age‐matched OVE diabetic mice to produce bi‐transgenic OVE‐JTMT diabetic progeny that carried the endothelial targeted JTMT transgene. Renal tissues from the OVE‐JTMT progeny were examined by unbiased TEM stereometry for possible GFB damage and other alterations from chronic complications of DN. In 150 day‐old OVE‐JTMT mice, blood glucose and HbA1c were indistinguishable from age‐matched OVE mice. However, endothelial‐specific MT overexpression in OVE‐JTMT mice mitigated several DN complications including significantly increased non‐fenestrated glomerular endothelial area, and elimination of glomerular basement membrane thickening. Significant renoprotection was also observed outside of endothelial cells, including reduced podocyte effacement, and increased podocyte and total glomerular cell densities. Moreover, when compared to OVE diabetic animals, OVE‐JTMT mice showed significant mitigation of nephromegaly, glomerular hypertrophy, increased mesangial cell numbers and increased total glomerular cell numbers. These results confirm the importance of oxidative stress to glomerular damage in DN, and show the central role of endothelial cell injury to the pathogenesis of chronic complications of diabetes. Anat Rec, 2017. © 2017 Wiley Periodicals, Inc. Anat Rec, 300:560–576, 2017. © 2016 The Authors. The Anatomical Record published by Wiley Periodicals, Inc. on behalf of American Association of Anatomists.