Voltage associated with spontaneous embryonic motility in the developing chicken: an automated characterization during mid-late embryogenesis

Movement of developing chicken embryos and their associated membranes generates voltage detectable with electrodes inserted just beneath the eggshell. Use of such voltages as a motility indicator offers an embryonic behavioral assessment method less subjective and invasive than observational methods using windows that disrupt substantial portions of the eggshell. We used a computerized signal recording and processing procedure to compare voltages from embryonic Day 12 (E12), E15, and E18 chicken eggs with embryos, assessed on the same day. Larger voltages were recorded from E18 subjects than from E12 or E15 subjects. Because this could have been due to embryonic size (mass) and/or proximity to the electrodes, making age comparisons uninterpretable, we used standard deviation-normalized and Z-score-based data transformations, comparing groups for relative deviations from basal voltages. E18 subjects still appeared more active than E12 subjects, with E15 a transitional age, in contrast to results from earlier window-based studies. The automated assessment method we used could enhance behavioral teratology studies of avian species.     

Evidence of decreased adhesion between the neural retina and retinal pigmented epithelium of the Mitfvit (vitiligo) mutant mouse

Secretoneurin, derived from the chromogranin secretogranin II, triggers the selective migration of human monocytes, eosinophils, fibroblasts, endothelial and smooth muscle cells. More recently, we located specific binding sites on the human monocytic cell line MonoMac-6. Differentiated U937 transendothelial diapedesis was evaluated using an in vitro model of the vascular wall and specific monoclonal antibodies against CD11/CD18 and the alpha-chains of the very late activation antigen (VLA)-4 were used to evaluate involved adhesion molecules. Results showed a significant migratory response to secretoneurin between 10(-8) to 10(-10) M. Migration was comparable to a maximal effect induced by the monocyte chemotactic agent N-formyl-Met-Leu-Phe (fMLP, 10(-8) M). Rabbit anti-secretoneurin antibodies were able to block the neuropeptide effect but not of fMLP and a trypsinized secretoneurin preparation as well as the secretogranin II-fragment EL-17 were ineffective in eliciting migration. Transmigration of U937 across endothelial-layers toward secretoneurin is inhibited by antibodies to CD11/CD18 adhesion molecules. The novel neuropeptide secretoneurin may play a role in regulating migration of monocytes into the subendothelial space, supposing a role in inflammatory responses.     

Homeless youths and young adults in Los Angeles: prevalence of mental health problems and the relationship between mental health and substance abuse disorders

Although understanding of the subsistence patterns, service utilization, and HIV-risk behaviors of homeless youths and young adults in increasing, relatively little is known about the epidemiology of mental health problems in this group or the relationships between mental health problems and substance use. This study measured symptoms of depression, low self-esteem, ADHD, suicidality, self-injurious behavior (SIB), and drug and alcohol use disorder in a sample of homeless youth and young adults living in Hollywood, CA. Results indicated extremely high prevalences of mental health problems as compared with corresponding rates of mental health problems found among housed youths in previous studies. Prevalence of mental health problems differed by age and ethnicity. African Americans were at lower risk of suicidal thoughts and SIB than were those of other ethnicities. Older respondents and females were at increased risk of depressive symptoms, and younger respondents were at increased risk of SIB. Previous history of sexual abuse and/or assault was associated with increased risk of suicidality and SIB. Risk factors for drug abuse disorders included ethnicity other than African American, homelessness for 1 year or more, suicidality, SIB, depressive symptoms, and low self-esteem. Risk factors for alcohol abuse disorder included male gender, white ethnicity, homelessness for 1 year or more, suicidality, and SIB. Extremely high rates of mental health problems and substance abuse disorders in this sample suggest the need for street-based and nontraditional mental health services targeted toward these youths and young adults.     

A second serine protease associated with mannan-binding lectin that activates complement

The complement system comprises a complex array of enzymes and non-enzymatic proteins that is essential for the operation of the innate as well as the adaptive immune defence. The complement system can be activated in three ways: by the classical pathway which is initiated by antibody-antigen complexes, by the alternative pathway initiated by certain structures on microbial surfaces, and by an antibody-independent pathway that is initiated by the binding of mannan-binding lectin (MBL; first described as mannan-binding protein) to carbohydrates. MBL is structurally related to the complement C1 subcomponent, C1q, and seems to activate the complement system through an associated serine protease known as MASP (ref. 4) or p100 (ref. 5), which is similar to C1r and C1s of the classical pathway. MBL binds to specific carbohydrate structures found on the surface of a range of microorganisms, including bacteria, yeasts, parasitic protozoa and viruses, and exhibits antibacterial activity through killing mediated by the terminal, lytic complement components or by promoting phagocytosis. The level of MBL in plasma is genetically determined, and deficiency is associated with frequent infections in childhood, and possibly also in adults (for review, see ref. 6). We have now identified a new MBL-associated serine protease (MASP-2) which shows a striking homology with the previously reported MASP (MASP-1) and the two C1q-associated serine proteases C1r and C1s. Thus complement activation through MBL, like the classical pathway, involves two serine proteases and may antedate the development of the specific immune system of vertebrates.     

Hydrolysis of phosphodiesters through transformation of the bacterial phosphotriesterase

The phosphotriesterase from Pseudomonas diminuta catalyzes the hydrolysis of a wide array of phosphotriesters and related phosphonates, including organophosphate pesticides and military nerve agents. It has now been shown that this enzyme can also catalyze the hydrolysis of phosphodiesters, albeit at a greatly reduced rate. However, the enzymatic hydrolysis of ethyl-4-nitrophenyl phosphate (compound I) by the wild-type enzyme was >10(8) times faster than the uncatalyzed reaction (kcat = 0.06 s-1 and Km = 38 mM). Upon the addition of various alkylamines to the reaction mixture, the kcat/Km for the phosphodiester (compound I) increased up to 200-fold. Four mutant enzymes of the phosphotriesterase were constructed in a preliminary attempt to improve phosphodiester hydrolysis activity of the native enzyme. Met-317, which is thought to reside in close proximity to the pro-S-ethoxy arm of the paraoxon substrate, was mutated to arginine, alanine, histidine, and lysine. These mutant enzymes showed slight improvements in the catalytic hydrolysis of organophosphate diesters. The M317K mutant enzyme displayed the most improvement in catalytic activity (kcat = 0.34 s-1 and Km = 30 mM). The M317A mutant enzyme catalyzed the hydrolysis of the phosphodiester (compound I) in the presence of alkylamines up to 200 times faster than the wild-type enzyme in the absence of added amines. The neutralization of the negative charge on the oxygen atom of the phosphodiester by the ammonium cation within the active site is thought to be responsible for the rate enhancement by these amines in the hydrolytic reaction. These results demonstrate that an active site optimized for the hydrolysis of organophosphate triesters can be made to catalyze the hydrolysis of organophosphate diesters.     

Role of luminal volume changes in the increase in pulmonary blood flow at birth in sheep

The mechanism by which pulmonary blood flow increases and pulmonary vascular resistance decreases after birth is not fully understood. The aim of this study was to simulate the decrease in lung volume caused by the onset of air-breathing at birth and determine whether it can duplicate the changes in pulmonary blood flow and vascular resistance that occur at this time. In chronically catheterized fetal sheep near term (145 days of gestation), fetal pulmonary arterial blood flow was measured, using coloured microspheres, before and after fetal lung liquid volumes were reduced from 52.2 +/- 2.7 to 21.2 +/- 1.6 ml kg-1. During the 30 min period following the reduction in lung liquid volume, the pulmonary-to-systemic arterial pressure difference decreased from 6.8 +/- 1.2 mmHg (pulmonary > systemic) to 1.6 +/- 0.5 mmHg. Reducing the volume of fetal lung liquid increased pulmonary blood flow from 59.1 +/- 10.5 to 204.2 +/- 40.4 ml min-1 (100 g tissue)-1 and reduced pulmonary vascular resistance from 0.53 +/- 0.20 to 0.14 +/- 0.04 mmHg min ml-1 (100 g tissue)-1. We conclude that a reduction in fetal lung liquid volume, which simulates the reduction in lung volume that occurs at birth, causes a 3- to 4-fold increase in pulmonary blood flow and a reduction in pulmonary vascular resistance of a similar magnitude. Thus, the reduction in lung volume associated with the lung changing from a liquid- to an air-filled organ, may partly account for the increase in pulmonary blood flow and decrease in pulmonary vascular resistance at birth.     

A prostate gland volume of more than 75 cm3 predicts for a favorable outcome after radical prostatectomy for localized prostate cancer

OBJECTIVE: This study aimed to describe the morphology of cystic disorders of the corneal epithelium by confocal microscopy. DESIGN: The study design was a prospective evaluation of confocal microscopic images of patients with cystic corneal disorders. PARTICIPANTS: Thirteen patients (19 eyes) were included. The corneal disorders included four patients with corneal decompensation (Fuchs' dystrophy), five patients with epithelial basement membrane dystrophy (e.g., Cogan's microcystic and map-dot dystrophies), one patient with Meesmann's dystrophy, and three patients with recurrent erosion syndrome of unknown etiology. Confocal images of diseased corneas were compared with those of ten normal control eyes (ten subjects). INTERVENTION: All patients were examined by slit-lamp biomicroscopic analysis and confocal microscopic analysis (Tomey, Erlangen-Temmenlohe, Germany). Image analysis was used to identify the corneal epithelial structures correlated with the corresponding pathology. MAIN OUTCOMES MEASURES: Confocal microscopy was used to assess the size, shape, light scatter, and reflection of the cysts. RESULTS: Slit-lamp examination results showed corneal epithelial cystic lesions in all cases. Confocal microscopy was able to identify cystic lesions in 9 (69.2%) of 13 patients. Of the four patients in whom lesions could not be found by confocal microscopy, three had recurrent erosion syndrome and the other one had epithelial basement membrane dystrophy. The confocal images were compatible with the clinical and histologic pictures of the disease. Normal control eyes did not show any epithelial lesion, either by biomicroscopy or confocal microscopy. CONCLUSIONS: Confocal microscopy provides an in vivo evaluation of cystic epithelial corneal lesions. This study shows that confocal microscopy is suitable for examining cystic lesions of the corneal epithelium. Nevertheless, it is not as sensitive as biomicroscopy in detecting cystic lesions in certain corneal conditions.     

Expression of chemokine receptors CXCR4 and CCR5 in HIV-1-infected and uninfected individuals

The chemokine receptors CXCR4 and CCR5 have been identified as major coreceptors for HIV-1 entry into CD4+ T cells. The majority of primary HIV-1 isolates in early disease use CCR5 as a coreceptor, whereas during disease progression with the emergence of syncytium-inducing viruses, CXCR4 is also used. We performed a cross-sectional study in which we evaluated the expression of two HIV-1 coreceptors, CCR5 and CXCR4, in whole blood samples taken from HIV-1-infected and uninfected individuals. We demonstrate that CXCR4 on CD4+ and CD8+ T cells, and CD14+ monocytes is significantly down-regulated, and CCR5 expression on CD4+ T cells is up-regulated in HIV-infected individuals compared with uninfected controls. Coreceptor expression correlated with the level of cellular activation in vivo in both HIV-infected and uninfected individuals, with CXCR4 being expressed predominantly on quiescent (HLA-DR-) T cells and CCR5 being expressed predominantly on activated (HLA-DR+) T cells. Lower expression of CXCR4 and higher expression of CCR5 on CD4+ T cells correlated with advancing disease. In addition, a tendency for greater activation of CXCR4+CD4+ T cells in patients with advanced disease was observed. Patients who harbored syncytium-inducing viruses, however, could not be distinguished from those who harbored nonsyncytium-inducing viruses based on the level of CD4+ T cell activation or chemokine receptor expression.