Benzodiazepines protect hippocampal neurons from degeneration after transient cerebral ischemia: an ultrastructural study

The ability of full and partial benzodiazepine receptor agonists to prevent DNA fragmentation and neuronal death after transient cerebral ischemia was investigated in the Mongolian gerbil. Diazepam (10mg/kg, i.p.) or the partial agonist imidazenil (3mg/kg, i.p.) was administered 30 and 90min after transient forebrain ischemia produced by occlusion of the carotid arteries for 5min. Treatment with diazepam completely protected CA1b hippocampal pyramidal neurons in 94% of the animals and partially protected pyramidal neurons in 6% of the animals, as assessed with a standard Nissl stain three and four days after ischemia. DNA fragmentation was examined by the terminal dUTP nick-end labeling (TUNEL) reaction. Prior to cell death, there were no TUNEL-positive neurons in area CA1b. By three days after ischemia, when neuronal degeneration was nearly complete, 14 out of 16 gerbils exhibited a positive TUNEL reaction throughout area CA1b stratum pyramidale. In 13 out of 14 gerbils treated with diazepam, no TUNEL-positive neurons were observed in this region. Imidazenil was less effective than diazepam with respect to both neuroprotection and prevention of DNA fragmentation. Three days after ischemia, six out of eight gerbils treated with imidazenil showed partial to complete neuroprotection. Imidazenil completely prevented DNA fragmentation in only one of the animals; varying degrees of TUNEL reaction persisted in the remainder. To determine whether the neurons protected by diazepam had a normal ultrastructure, gerbils were killed two to 30 days after ischemia and the hippocampal neurons in area CA1b were examined by electron microscopy. Within the first 48h after ischemia, early cytoplasmic changes of varying degrees (e.g., vacuolation, rough endoplasmic reticulum stacking, swollen mitochondria) and electron-dense dendrites were observed in gerbils not treated with diazepam. Degeneration was nearly complete by three days after ischemia. In contrast, pyramidal neuron ultrastructure appeared normal in gerbils that exhibited complete area CA1b neuroprotection (defined at the light microscope level) by diazepam when studied two, seven or 30 days after ischemia. In gerbils with partial protection of area CA1b, most of the remaining neurons exhibited varying degrees of necrosis when studied 30 days after ischemia. No apoptotic bodies were observed.We conclude that: (i) diazepam can fully protect CA1 pyramidal cells from the toxic effects of transient cerebral ischemia; (ii) when diazepam affords only partial neuroprotection, the residual CA1 pyramidal cells exhibit ultrastructural abnormalities consistent with necrotic damage; and (iii) diazepam is a more efficacious neuroprotectant than the partial benzodiazepine receptor agonist, imidazenil.     

Reduced levels of Hsp70 result in a therapeutic effect of 15-deoxyspergualin on acute graft-versus-host disease in (DA x LEW)F1 rats

We have shown previously that increased levels of hsp70, and antibodies reactive with hsp70 parallel the onset and severity of graft-versus-host disease (GVHD) in a parent --> (DA x LEW)F1 rat model. In this study we have assessed the effect of reducing the levels of the 70 kDa heat shock protein (hsp70), on the morbidity and mortality of acute GVHD in (DA x LEW)F1 rats. The reduction was accomplished by the administration of 15-deoxyspergualin (DSG), an immunosuppressive agent which binds to a constitutively expressed member of the 70 kDa heat shock protein family. DSG administered via three different protocols reduced GVHD-associated morbidity. One of the regimens, which consisted of intermittent DSG administration, also significantly reduced GVHD associated mortality. This DSG treatment reduced hsp70 levels in spleen and lymph nodes, inhibited anti-hsp70 antibody production, and diminished the serum levels of IL-2, IFN-gamma, TNF-alpha, and IL-10. IL-4 levels in the serum did not change during GVHD and were not effected by DSG. These results show that the mechanism of DSG immunosuppressive effect in rat GVHD may involve DSG's capacity to bind to hsp70, which in turn may lead to a decrease in levels of circulating anti-hsp70 antibodies, and reduced production of cytokines.     

Investigations of peritoneal and intestinal infections of adult hookworms (Uncinaria spp.) in northern fur seal (Callorhinus ursinus) and California sea lion (Zalophus californianus) pups on San Miguel Island, California (2003)

The peritoneal cavity (PNC) and intestine of northern fur seal (Callorhinus ursinus) pups and California sea lion (Zalophus californianus) pups that died in late July and early August, 2003, on San Miguel Island, California, were examined for hookworms. Prevalence and morphometric studies were done with the hookworms in addition to molecular characterization. Based on this and previous molecular studies, hookworms from fur seals are designated as Uncinaria lucasi and the species from sea lions as Uncinaria species A. Adult hookworms were found in the PNC of 35 of 57 (61.4%) fur seal pups and of 13 of 104 (12.5%) sea lion pups. The number of hookworms located in the PNC ranged from 1 to 33 (median = 3) for the infected fur seal pups and 1 to 16 (median = 2) for the infected sea lion pups. In addition to the PNC, intestines of 43 fur seal and 32 sea lion pups were examined. All of these pups were positive for adult hookworms. The worms were counted from all but one of the sea lion pups. Numbers of these parasites in the intestine varied from 3 to 2,344 (median = 931) for the fur seal pups and 39 to 2,766 (median = 643) for the sea lion pups. Sea lion pups with peritoneal infections had higher intensity infections in the intestines than did pups without peritoneal infections, lending some support for the hypothesis that peritoneal infections result from high-intensity infections of adult worms. There was no difference in intestinal infection intensities between fur seal pups with and without peritoneal infections. Female adult hookworms in the intestines of both host species were significantly larger than males, and sea lion hookworms were larger than those in fur seals. Worms in the intestine also were larger than worms found in the PNC. Gene sequencing and (RFLP) analysis of (PCR) amplified (ITS) ribosomal DNA were used to diagnose the species of 172 hookworms recovered from the PNC and intestine of 18 C. ursinus and seven Z. californianus hosts. These molecular data revealed that U. lucasi (hookworm of C. ursinus) and Uncinaria species A (of Z. californianus) infrequently mature in the intestine of the opposite host species in California rookeries. However, there is no support from molecular data for the hypothesis that cross-infection with “the wrong” Uncinaria species is a contributing factor in these cases of host peritonitis. The major significance of this research is the unusual finding of adult hookworms in the PNC of so many dead pups. No obvious explanation for this occurrence could be determined. Further research, like in the present study, should help understand and monitor the apparent ever changing role of hookworm disease in the health of northern fur seal and California sea lion pups on SMI.     

Salivary gland involvement in hypohidrotic ectodermal dysplasia

Ectodermal dysplasias (EDs) are a group of developmental disorders (more than 100) mainly affecting ectodermal tissues and organs. The X-linked hypohidrotic ED (HED) is the most common form of EDs, involving defects in teeth, sweat glands, and hair. In a few reports, HED has been associated with reduced salivary function. In the present case report, a dramatically reduced salivary fluid and acidic proline rich protein production was identified in a 38-year-old man with HED. Computed tomography was performed, revealing that one submandibular gland and both parotid glands were hypoplastic, whereas the right submandibular gland seemed to be absent. These findings are in line with a general developmental disturbance also involving the salivary glands. As salivary tests are inexpensive and easy to perform, it is suggested to routinely evaluate salivary secretion in persons with HED, to prevent a possible negative impact on oral health.     

Renal thorium deposition associated with transitional cell carcinoma: radiologic demonstration in two patients

Abdominal radiography, excretory urography, retrograde pyelography, and computed tomography were performed in two patients who had undergone retrograde pyelography with thorium dioxide (Thorotrast) approximately 40 years ago. Both patients developed a transitional cell carcinoma due to suburothelial thorium deposition. Typical thorium densities were demonstrated at CT in the peripelvicalyceal area as well as in retroperitoneal lymph nodes. Elderly patients in whom radiographic examination reveals retained Thorotrast in the kidney should be followed up because of the high risk of renal carcinoma.     

Perceived Social Support for Exercise and Weight Loss in Adolescents Undergoing Sleeve Gastrectomy

Objectives

Bariatric surgery is an effective treatment for youth with severe obesity. However, outcomes are variable and there remains sparse understanding of predictors of weight loss following surgery. The current study examines the role of adolescent-reported pre-operative social support around exercise, binge eating, and exercise to predict excess body mass index (EBMI) loss from 3 to 12 months post-surgery.

Method

Participants were 101 adolescents ages 12–21 (M age = 16.6, SD = 1.8). Pre-operative body mass index (BMI) ranged from 35 to 87 (M = 50.3, SD = 8.6). Structural equation modeling (SEM) was used to evaluate a model of the association of adolescent report of perceived social support for exercise with less binge eating (items from the Eating Disorder Diagnostic Scale) and more self-reported exercise (items from the Youth Risk Behavior Surveillance System). The model was used to predict EBMI loss at 3, 6, 9, and 12 months post-surgery.

Results

Social support significantly predicted exercise and demonstrated a trend for predicting binge eating, such that more social support was associated with more exercise and a trend for less binge eating. Binge eating was associated with less EBMI loss. However, there was no association of exercise with EBMI loss.

Conclusions

Pre-operative binge eating should be a target for identification and treatment prior to sleeve gastrectomy in adolescents. Although not directly or indirectly associated with EBMI loss, perceived social support around exercise was associated with increased exercise, which may make it a consideration for a target for intervention as well.

     

The Sequential Relation Between Changes in Catastrophizing and Changes in Posttraumatic Stress Disorder Symptom Severity

Catastrophizing has been discussed as a cognitive precursor to the emergence of posttraumatic stress disorder (PTSD) symptoms following the experience of stressful events. Implicit in cognitive models of PTSD is that treatment-related reductions in catastrophizing should yield reductions in PTSD symptoms. The tenability of this prediction has yet to be tested. The present study investigated the sequential relation between changes in a specific form of catastrophizing—symptom catastrophizing—and changes in PTSD symptom severity in a sample of 73 work-disabled individuals enrolled in a 10-week behavioral activation intervention. Measures of symptom catastrophizing and PTSD symptom severity were completed at pre-, mid-, and posttreatment assessment points. Cross-sectional analyses of pretreatment data revealed that symptom catastrophizing accounted for significant variance in PTSD symptom severity, β = .40, p < .001, sr = .28 (medium effect size), even when controlling for known correlates of symptom catastrophizing, such as pain and depression. Significant reductions in symptom catastrophizing and PTSD symptoms were observed during treatment, with large effect sizes, ds = 1.42 and 0.94, respectively, ps < .001. Cross-lagged analyses revealed that early change in symptom catastrophizing predicted later change in PTSD symptoms; early changes in PTSD symptom severity did not predict later change in symptom catastrophizing. These findings are consistent with the conceptual models that posit a causal relation between catastrophizing and PTSD symptom severity. The clinical implications of the findings are discussed.     

Assessment of human pancreatic islets after long distance transportation

Pancreatic islet transplantation can replace functional insulin-secreting beta cells for patients with type 1 diabetes. More than 300 patients who have received islet transplantation have returned to a euglycemic condition without using insulin. Therefore, islet transplantation has gained public attention and interest. Unfortunately, shortages in organ donations, suboptional antirejection regimens, and difficulties in islet isolation limit clinical utilization of this therapy. Recently, successful islet transplantation has been reported using a centralized islet isolation facility. The advantage of this experience is that it avoids the high costs in building an isolation facility and maintaining an experienced technical team. However, a private airplane carrier was required for transporting islets back to the transplantation site in a remote hospital. The cost of this specialized transportation was still too high to be considered as a routine procedure. In this study, we report our experience using commercial carriers to deliver isolated human islets from an established isolation facility to a remote medical center.     

Heterogeneity of human whole blood platelet subpopulations. III. Density-dependent differences in subcellular constituents

Structurally intact platelet cohorts of differing densities can be isolated from normal subjects by the use of isosmolar arabinogalactan density gradients. Using platelets separated in this fashion, we have studied the density-dependent distribution of four subcellular organelles: mitochondria, lysosomes, dense bodies, and alpha granules. Mitochondria, which are not secreted during platelet release, demonstrate a slow decline in monoamine oxidase activity within the gradient. Lysosomal beta-glucuronidase does not vary significantly with platelet density. In contrast, dense body number and endogenous serotonin content decrease significantly with decreasing platelet density, primarily as the result of differences in the number of storage organelles. Platelet factor 4 content declines rapidly in comparison to lysosomal activities (P less than .001 from bottom to top of the gradient); but beta-thromboglobulin, also an alpha granule component, exhibits considerably less change than platelet factor 4 (P less than .001). Thus, specific platelet subcellular constituents have different density distributions. We postulate that these density differences may be due to differential in vivo loss of selective biochemical constituents from unique subcellular compartments.