Variables associated with subjective cognitive change among Iraq and Afghanistan war Veterans with blast-related mild traumatic brain injury

Introduction: This study investigated variables associated with subjective decline in executive function among Veterans of Operations Enduring Freedom, Iraqi Freedom, and New Dawn (OEF/OIF/OND) following a history of blast-related mild traumatic brain injury (mTBI).

Method: Fifty-six male U.S. Veterans (M_Age = 35.3 ± 8.8 years) with a history of blast-related mTBI (6.6 ± 3.2 years post injury) completed a battery of self-report questionnaires and neuropsychological measures. Participants rated current and retrospectively estimated pre-mTBI executive function difficulties on the Frontal Systems Behavior Scale (FrSBe). A difference score (post- minus pre-mTBI ratings) was the dependent variable (?FrSBe). Linear regression models examined variables predicting ?FrSBe, including: pre-injury characteristics (education, premorbid intelligence), injury-related characteristics (number of blast exposures, losses of consciousness), post-injury clinical symptoms (PTSD Checklist–Military version; Pittsburgh Sleep Quality Index), and post-injury neuropsychological performances on executive function measures (Trail Making Test Part B; Controlled Oral Word Association Test; Auditory Consonant Trigrams; Wisconsin Card Sorting Test).

Results: While 11% of participants had a clinically elevated pre-injury FrSBe total score, 82% had a clinically elevated post-injury FrSBe total score. Only self-reported PTSD symptom severity independently predicted perceived change in executive function.

Conclusions: Many OEF/OIF/OND Veterans with a history of blast-related mTBI experience subjective decline in executive function following injury. Perceived executive function decline was associated with higher PTSD symptom severity, aligning with previous research associating PTSD with cognitive complaints. Results did not support a correspondence between perceived cognitive change and neuropsychological performances.     

Does age affect the stress and coping process? Implications of age differences in perceived control

The perceived controllability of situations is thought to influence the types of coping strategies used, and thus is important in adaptive processes. Elderly individuals are widely perceived to have less control over their environment than other adults. This lack of perceived control should have adverse affects on how they cope with stressful situations. However, most studies have shown that older adults differ little from younger adults in their approaches to coping with stress. This contradiction was investigated in a sample of 228 community-residing adults with a mean age of 42.16 (SD = 14.88). Path analysis revealed that appraisals and attributions do affect the use of coping strategies such as instrumental action and escapism in the expected directions, and age is negatively associated with perceived control. However, there was an independent and negative relationship between age and the reported use of escapist coping strategies, which mitigated the adverse effects of perceived lack of control. Neither age nor perceived controllability had direct effects on depression, but they had indirect effects through their influence on the use of coping strategies and perceived efficacy.     

Nonisotopic M13 probes for detecting the beta-globin gene: application to diagnosis of sickle cell anemia

M13 DNA probes labeled with biotinylated psoralen and a streptavidin-horseradish peroxidase conjugate provide nonradioactive detection of the sickle cell and normal alleles of the beta-globin locus. The two biotinylated probes contain single-stranded sequences complementary to two different Sau3AI restriction fragments from the 5' region of the beta-globin gene and double-stranded M13 vector sequences. These probes are labeled with biotinylated psoralen photochemically linked to DNA. After hybridization, the presence of biotinylated probe bound to target DNA is detected in 3 h by using a streptavidin-horseradish peroxidase conjugate and the substrate, 3,3',5,5'-tetramethylbenzidine. Digestion of the normal (beta A) allele of the beta-globin gene with MstII (or isoschizomers) yields a 1.14-kb restriction fragment, while digestion of the mutant beta S allele yields a 1.34-kb fragment. These fragments can be resolved by gel electrophoresis and detected by Southern blot hybridization. The nonradioisotopic probe system can detect the beta-globin restriction fragment in as little as 0.5 microgram of human DNA and can distinguish heterozygotes (beta A beta S) from homozygotes (beta A beta A or beta S beta S) in 2.0 micrograms of human DNA.     

How stressful is retirement? Findings from the Normative Aging Study

The stressfulness of retirement both as a transitional event experienced during the past year and as a life stage was investigated. Transitional stress was assessed using a life events approach, and stage stress using a "hassles" approach. Respondents were 1,516 male participants in the Normative Aging Study, 45% of whom were retired. Among those retiring in the past year, respondents' own and spouse's retirement were rated the least stressful from a list of 31 possible events. Only 30% found retirement stressful. Retirement hassles were also less frequently reported and were rated less stressful than the work hassles of men still in the labor force. The only consistent predictors of both transitional and stage retirement stress were poor health and family finances; personality did not predict retirement stress.     

Hepatic synthesis of canavaninosuccinate from ureidohomoserine and aspartate, and its conversion to guanidinosuccinate.

This study continues the exploration of the mechanism for the formation of guanidinoacetate and guanidinosuccinate in the human [Clin. Chem. 21, 235 (1975)]. In this report we describe the formation of canavaninosuccinate from ureidohomoserine and aspartate by a human or bovine liver extract that had high argininosuccinate synthetase (EC 6.3.4.5) activity, and the subsequent formation of guanidinosuccinate by reductive cleavage. In the presence of ATP the optimum pH for the synthetic reaction is 8.4. This reaction can be carried out in either a tris(hydroxymethyl)aminomethane or borate buffer. Subsequent addition of dithiothreitol in the presence of Fe2+ resulted in the cleavage of some of the synthesized canavaninosuccinate to form guanidinosuccinate and homoserine. Synthesis of canavaninosuccinate was strongly inhibited by added argininosuccinate, less so by canavaninosuccinate, arginine, canavanine, glycine, or 2,3-dimercaptopropanol. The Km values for the substrates of the synthetic reaction are 3.6 X 10(-4) mol/liter for aspartate, 1.6 X 10(-3) mol/liter for ureidohomoserine, and 2.92 X 10(-5) mol/liter for ATP. These values are higher than those obtained when the synthesis of argininosuccinate was studied, except for ATP, which yielded a lower value. All of the reactions in the proposed mechanism have now been demonstrated except for the synthesis of canaline from aspartate.     

Carbohydrate supplementation before operation retains intestinal barrier function and lowers bacterial translocation in a rat model of major abdominal surgery

BACKGROUND: Overnight fasting of rats augments the susceptibility of the small intestine to ischemia-reperfusion damage. Feeding before surgery may improve injuries to distant organs that were induced by ischemia-reperfusion. The present study tested the hypothesis that one of the food constituents, namely carbohydrates, may be responsible for the protective effect of preoperative feeding on postoperative organ dysfunction. METHODS: Male Wistar rats were fed ad libitum for 5 d and had either free access to water or free access to a carbohydrate drink and water. Then they were fasted for 16 h and access remained to either water or a carbohydrate drink and water. Following this, the arteria mesenterica superior was clamped for 60 min followed by 180 min of reperfusion. Subsequently, the intestinal permeability of stripped ileum was determined by measuring the mucosal to serosal flux in Ussing chambers. For assessment of bacterial content, organs were aseptically removed and assessed for bacterial content by culture under anaerobic conditions. RESULTS: Preoperative supplementation with carbohydrates resulted in a better maintenance of intestinal barrier function when compared with water supplemented animals. Moreover, carbohydrate supplementation resulted in a reduction in the ischemiareperfusion-induced increase in bacterial content of the liver, kidney, and mesenteric lymph nodes. CONCLUSIONS: Preoperative intake of carbohydrates by rats retains both the intestinal barrier function and prevents translocation of bacteria to distant organs.     

Modeling age using cognitive, psychosocial and physiological variables: the Boston Normative Aging Study.

A structural equation model is computed for 36 variables from eight domains of data using 100 healthy male subjects whose age varies between 30 and 80 years. Chronological age is required to be an exogenous variable while cognitive function variables are required to be an ultimate endogenous or outcome set. The model suggests that the direct effect of age on cognition is substantially reduced when social, life style, physiological, and brain state variables are allowed to become intervening variables. The study also finds that there is an association between cognitive function and psychosocial measures relating to general psychiatric symptomatology and social support systems.