Personality Assessment Inventory suicidality scales: Suicidal Ideation (SUI), Suicide Potential Index (SPI), and S_Chron in an Afghanistan/Iraq-era active and Veteran military sample

INTRODUCTION

This study validated Personality Assessment Inventory (PAI) Suicidal Ideation (SUI), Suicide Potential Index (SPI), and S_Chron scales against chronic and acute suicide risk factors and symptom validity measures.

METHODS

Afghanistan/Iraq-era active-duty and Veteran participants completed a prospective study on neurocognition (N = 403) that included the PAI. The Beck Depression Inventory-II (specifically item 9) administered at two time points assessed acute and chronic suicide risk; the Beck Scale for Suicide Ideation item 20 identified history of suicide attempts. Major depressive disorder (MDD), posttraumatic stress disorder (PTSD), and traumatic brain injury (TBI) were evaluated using structured interviews and questionnaires.

RESULTS

All three PAI suicide scales were significantly related to independent indicators of suicidality, with the largest effect for SUI (AUC 0.837-0.849). All three suicide scales were significantly related to MDD (r = 0.36-0.51), PTSD (r = 0.27-0.60), and TBI (r = 0.11-0.30). The three scales were not related to suicide attempt history for those with invalid PAI protocols.

CONCLUSIONS

Although all three suicide scales do show significant relationships to other indicators of risk, SUI showed the highest association and greatest resistance to response bias.

Influence of the level of dietary lipid intake and maximal exercise on the immune status in runners

Chronic exercise and high fat diets are associated with immune suppression. This study compares cellular immune responses at rest and after maximal exercise in runners after eating diets comprised of 17% low fat (LF), 32% medium fat (MF), and 41% high fat (HF) (4 wk each). VO2max increased significantly from the 17% to 41% fat diet. The leukocyte cell counts were significantly increased after exercise. In men, significantly higher proliferative response to phytohemagglutinin (PHA) (P < 0.004) was observed with MF diet, while response to pokeweed mitogen (PWM) was significantly decreased by MF and HF diets. The number of CD8+ (suppressor) T cells was significantly higher in men and exercise increased it significantly, while CD4+ (helper) T cells were not affected. Natural killer cells number was significantly increased 2.5 fold by exercise and with increase in dietary fat. The production of IL-2 by peripheral blood mononuclear cells was significantly higher in men (P < 0.0001) and increasing dietary fat significantly increased IL-2 production (P < 0.001). In men, exercise decreased the level of the proinflammatory cytokines (IL-1, IL-6 and TNF-alpha), whereas in women, with the exception of MF diet for IL-6, exercise had no effect. This study indicates that short, intense bouts of exercise in runners training 40 miles.wk-1 have mixed effects on the immune system. A high percentage of fat intake (41%) did not have any deleterious effects on the immune system of the well-trained runners.

Tumour necrosis factor increases tumour uptake of co-administered antibody-carboxypeptidase G2 conjugate

Increased tumour uptake of antibodies and antibody-drug conjugates has been demonstrated following pretreatment of animals with recombinant human tumour necrosis factor-alpha (rTNF-alpha) and interleukin 2 immunoconjugates. The experiments reported here were performed to determine whether improved tumour localisation of antibody-carboxypeptidase G2 conjugates could be achieved, with a view to applying this technology to antibody-directed enzyme-prodrug therapy (ADEPT). B6CF1 mice bearing the Ly-2.1+ murine thymoma E3 were simultaneously injected with 2.0 micrograms rTNF-alpha and 3.5 micrograms (74kBq) 125I-labelled murine anti-Ly-2.1-CPG2 conjugate. Mice in control groups received phosphate buffered saline in place of rTNF-alpha. The conjugate corresponded in molecular weight to a mixture of 1:1 and 2:1 (CPG2:IgG) conjugate and retained its antigen binding specificity and enzymic activity in vitro. A significant increase in tumour uptake was observed 24 h after administration when rTNF-alpha-treated animals were compared to controls (28.1 +/- 9.7%/g and 11.6 +/- 2.3%/g, respectively). Other tissues, most notably gut, skin and kidney also showed an increased localisation of conjugate. By 48 h, analysis of tissue:blood ratios demonstrated that although tumour:blood ratios were significantly higher in rTNF-alpha-treated animals (P < 0.05), all the other tissue:blood ratios were not significantly different between the two groups.

Kinetics of secretion of luteinizing hormone subunits and free alpha, and effects of gonadotropin releasing hormone

While GnRH is known to stimulate release of pituitary gonadotropins, its acute effects on the kinetics of secretion of the various hormones and subunits are not well characterized. Pulse-chase experiments were therefore performed to compare the time course of secretion of newly synthesized LH subunits and free alpha from rat pituitary quarters, and to study the effects of GnRH. After a 1-h pulse labeling with [35S]cysteine in the presence or absence of 10(-8) M GnRH, cultures were chased with excess unlabeled cysteine for 1, 2, 4, 8, or 20 h. Tissue lysates and media were immunoprecipitated sequentially with antisera to PRL, GH, LH beta and LH alpha, and the products were analyzed by gel electrophoresis. Labeled LH alpha was completely secreted by 4 h of chase without GnRH, and by 2 h with GnRH, as shown by its appearance in media and depletion from pituitary. Newly synthesized LH beta was depleted only at 8 h with GnRH from pituitary, suggesting much slower secretion. Incorporation of 35S into LH beta was approximately half that into LH alpha. Newly synthesized free alpha subunit was secreted between 4 and 20 h without GnRH, and by 8 h with GnRH. Free alpha incorporated a similar amount of radioactivity as LH beta. GnRH had no effect on the timing of the secretion of labeled total protein, PRL, GH, or TSH subunits. The amount of label incorporated during the pulse was greatest for PRL, approximately 15% of total protein label. GH incorporated approximately 20% as much label as PRL, with the glycoprotein subunits somewhat lower. The total amount of 35S incorporated into each protein studied was not affected by GnRH. The data indicate that short term in vitro GnRH exposure during a 1-h pulse labeling and chase acts to accelerate early secretion of LH alpha, LH beta and free alpha but does not affect overall protein synthesis. The peptide hormones PRL and GH incorporated the greatest amount of label and were the most briskly secreted hormones, while LH alpha led the glycoprotein subunits in the amount of incorporation and rapidity of secretion.