Acquired jejunoileal diverticulosis and its complications: a review of the literature

Jejunoileal diverticulosis is a rare entity. Jejunoileal diverticulosis is not a disease that surgeons see often in clinical practice; however, it should remain on the differential diagnosis for any patient with an acute abdomen or gastrointestinal bleeding of unknown origin. It can present with a wide range of clinical scenarios and when patients experience chronic symptoms such as bloating, abdominal pain, nausea, bacterial overgrowth, or malabsorption, medical therapy is successful in most patients. However, when patients present with acute symptoms of bleeding, inflammation, perforation, or obstruction, surgical resection and primary anastomosis is often the treatment of choice. If patients are asymptomatic, they are better left alone, even when discovered incidentally in the operating room. In closing, the possibility of a patient having jejunal diverticular disease should be suspected whenever the symptoms of obscure abdominal pain, anemia, dilated jejunal loops on abdominal radiographs, a history of colonic diverticuli, and a history of acute appendicitis.     

Replication ability of three highly protective Marek's disease vaccines: implications in lymphoid organ atrophy and protection

The present work is a chronological study of the pathogenesis of three attenuated serotype 1 Marek's disease (MD) virus strains (RM1, CVI988 and 648A80) that provide high protection against MD but have been attenuated by different procedures and induce different degrees of lymphoid organ atrophy. All studied strains replicated in the lymphoid organs (bursa,x thymus and spleen) and a peak of replication was detected at 6 days post inoculation (d.p.i.). Differences, however, were observed among vaccine strains. RM1 strain replicates more in all lymphoid organs compared with CVI988 and 648A80 strains. In addition, replication of RM1 in the thymus did not decrease after 6 d.p.i. but continued at high levels at 14 d.p.i. and until the thymus was completely destroyed. Lung infection occurred very early after infection with all of the three vaccines and the level of replication was similar to that found in the lymphoid organs. Infected cells were very large and appeared scattered in the lung parenchyma and in the parabronchial lining. The study of the target cells for the early infection in cell suspensions of blood and spleen showed that both non-adherent cell populations (enriched in lymphoid cells) and adherent cells (enriched in monocytes/macrophages) supported MD virus infection. Infection in adherent cells was especially high at very early stages of the infection (3 to 6 d.p.i.). Atrophy of lymphoid organs is a major drawback in the production of highly protective vaccines against MD. A better understanding of the mechanisms associated with lymphoid organ atrophy will aid in overcoming this problem.     

Plasmablastic lymphomas with light chain restriction – plasmablastic extramedullary plasmacytomas?

J Oral Pathol Med (2010) 39 : 435–439 Background: It is diagnostically difficult to differentiate plasmablastic lymphomas (PBLs) from plasma cell neoplasms with plasmablastic differentiation. Plasmablastic lymphomas are currently classified as ‘PBL of the oral mucosa’ and ‘PBL with plasmacytic differentiation’. Methods: Forty‐five cases of PBL were retrieved from the Departments of Oral Pathology of the Universities of Pretoria and Limpopo, South Africa. Clinical features and HIV status were recorded and each case was classified as ‘PBL of the oral mucosa type’ or as ‘PBL with plasmacytic differentiation’. Immunohistochemistry included: CD45, CD3, CD20, CD79a, CD38, CD138, MUM1, Ki‐67 and kappa and lambda light chains. Positivity was recorded based on the percentage of positive staining cells as focal (5–20%); intermediate (20–70%) or diffuse (>70%). In situ hybridization was performed for Epstein–Barr virus (EBV) and HHV‐8. Results were recorded as positive or negative. Results: All cases showed some degree of plasmacytic differentiation. All were negative for CD20 with reactive T cells detected with CD3. Diffuse and strong positive staining was found with Ki‐67 and MUM1, but variable immunoreactivity was found with CD79a, CD45, CD38 and CD138. Twenty cases (47%) showed light chain restriction. Epstein–Barr virus was detected in 44/45 cases and HHV‐8 in none. Conclusions: The morphological classification of PBLs is not valid as all cases showed some degree of plasmacytic differentiation. We propose that PBLs with light chain restriction be reclassified as ‘plasmablastic extramedullary plasmacytomas’ and managed accordingly. The rest represents true PBLs. The true nature of these neoplasms as an entity should be further investigated with molecular and genetic studies.     

Examination of the Factor Structure and Correlates of the Perceived Military Healthcare Stressors Scale

The current study evaluated the factor structure, reliability estimates, correlates, and predictive utility of the Perceived Military Healthcare Stressor Scale (PMHSS) in a sample of active duty military medical personnel (N = 1,131) deployed to Joint Base Balad in Iraq. The sample was composed of an approximately even split of male (51.2%) and female (48.8%) participants who ranged in age from 18 to 60 years. The PMHSS is a 21‐item measure that was designed to assess the impact of specific medical stressors that military healthcare providers may encounter while deployed. An exploratory factor analysis of the PMHSS revealed the presence of two distinct factors: trainable and futility stressors. Confirmatory factor analysis showed that a bifactor model best represented the data, with all items loading higher on the general factor relative to their specific subscale factors. Evidence of partial scalar invariance by gender was found. The PMHSS was significantly correlated with several convergent measures, including assessments of posttraumatic stress disorder (PTSD), depression severity, distress due to both combat exposure and general deployment‐related concerns, and positive affect, rs = .30–.59. PMHSS scores were more strongly correlated with PTSD and depression in women than in men, and they provided incremental validity in predicting convergent measures over and above other related constructs. Healthcare–specific stressors are an understudied area, and this study provides new insights into how deployment‐related caregiving stress may impact deployed military medical personnel independently of the impact of combat experiences.     

The World Health Organization child growth standards: expected implications for clinical and epidemiological research

In 2006 and 2007, the World Health Organization (WHO) released two sets of child growth standards (World Health Organization, WHO Child Growth Standards. Methods and development. Length/height-for-age, weight-for-age, weight-for-length, weight-for-height and body mass index-for-age. WHO, Geneva, 2006; World Health Organization, WHO Child Growth Standards: Methods and Development. Head circumference-for-age, arm circumference-for-age, triceps skinfold-for-age and subscapular skinfold-for-age. WHO, Geneva, 2007) to replace the National Center for Health Statistics references (Hamill et al., National Center for Health Statistics, Vital and Health Statistics Series 11, No 165, 1977) as an international tool for growth and nutritional assessment. This paper explores the scope of implications for future anthropometric research, highlighting foreseeable effects on the choice of research questions, choice of nutritional indices, training of measurers, and issues of internal and external validity of research results. The conclusion drawn is that the introduction of the WHO child growth standards is expected to have wide implications for growth and nutrition research. The full scope of this effect will gradually become clear while researchers, similar to health care workers, make the transition to using the new standards, re-evaluate results of past approaches, and explore the uses and functional validity of the standards, including those for indices that were not previously available.     

Biochemical Model for Inflammation of the Brain: The Effect of Iron and Transferrin on Monocytes and Lipid Peroxidation

Cerebral inflammation plays a role in diseases such as multiple sclerosis (MS), Alzheimer's disease (AD), and depression. Iron is involved in infection and inflammation through free radical production. Theoretically transferrin should prohibit iron from participating in oxidative reactions, but transferrin has also been found to promote free radical damage. We reported previously that isolation of transferrin from plasma by ion exchange column chromatography produced a broad pink protein band that subsequently separated on a gel filtration column into three proteins containing many metals. In this study some properties of the three proteins were studied in 20 volunteers. Protein 3 (identified as transferrin by nephelometry) contained the most iron while Protein 1 (called "toxiferrin") contained significantly less iron (p < 0.00001). Plasma from volunteers obtained under conditions of infection/inflammation with fever (n = 5) had a significantly increased toxiferrin to transferrin ratio compared to healthy volunteers (n = 15; p < 0.001). In vitro, Protein 2 and transferrin inhibited lipid peroxidation, while toxiferrin (possibly a protease degradation product of transferrin), enhanced lipid peroxidation. Also, toxiferrin (1 mg/mL) caused a significant increase in viability of monocytes as measured by the 3-(4,5-dimethyl-thiazol-2-yl) 2,5-diphenyl tetrazolium bromide (MTT) reduction test, as well as the morphological transformation of monocytes to macrophages.     

Neuromechanical features of the cardiac baroreflex after exercise

A single bout of exercise is associated with postexercise hypotension, transient decreases in autonomic function, and changes in baroreflex sensitivity. The baroreflex is less sensitive to falling blood pressure than to rising blood pressure; we characterized the cardiac baroreflex in terms of hysteresis and its mechanical and neural components. We hypothesized that hysteresis would be exacerbated postexercise because of a greater relative decrease in falling blood pressure. In 10 healthy young humans (5 men), we used bolus injections of sodium nitroprusside and phenylephrine hydrochloride to drive transient decreases and increases in blood pressure, respectively, to quantify cardiac baroreflex sensitivity to falling and rising blood pressure. This was completed before and at 10, 30, and 60 minutes after 40 minutes of cycling at 60% estimated maximal oxygen consumption. Analyses of beat-to-beat blood pressure, R-R intervals and heart rate, and carotid artery diameter were used to determine the integrated cardiac baroreflex response; this was further quantified into a mechanical component (systolic blood pressure versus carotid diameter) and a neural component (carotid diameter versus R-R interval). There were 2 principle findings: after aerobic exercise baroreflex sensitivity is reduced and hysteresis manifests, and the reduction in sensitivity to falling blood pressure is mediated by decreased mechanical and neural gains, whereas the decreased baroreflex sensitivity to rising blood pressure is mediated by a reduced mechanical gain only. We suggest that impaired neural transduction of the cardiac baroreflex, and its influence on hysteresis, plays an important role in transient autonomic dysfunction after exercise.     

Speciation in birds: genes, geography, and sexual selection

Molecular studies of speciation in birds over the last three decades have been dominated by a focus on the geography, ecology, and timing of speciation, a tradition traceable to Mayr's Systematics and the Origin of Species. However, in the recent years, interest in the behavioral and molecular mechanisms of speciation in birds has increased, building in part on the older traditions and observations from domesticated species. The result is that many of the same mechanisms proffered for model lineages such as Drosophila--mechanisms such as genetic incompatibilities, reinforcement, and sexual selection--are now being seriously entertained for birds, albeit with much lower resolution. The recent completion of a draft sequence of the chicken genome, and an abundance of single-nucleotide polymorphisms on the autosomes and sex chromosomes, will dramatically accelerate research on the molecular mechanisms of avian speciation over the next few years. The challenge for ornithologists is now to inform well studied examples of speciation in nature with increased molecular resolution-to clone speciation genes if they exist--and thereby evaluate the relative roles of extrinsic, intrinsic, deterministic, and stochastic causes for avian diversification.