Down-regulation of glial fibrillary acidic protein expression during acute lytic varicella-zoster virus infection of cultured human astrocytes

The effects of the varicella-zoster virus (VZV) OKA vaccine strain in producing morphologic and antigenic changes in dissociated cultures of human fetal brain was investigated. Cultures containing 80% glial acidic fibrillary protein (GFAP), GFAP+ (positive) astrocytes and 20% GFAP- (negative) fibroblastic-like cells were infected with cell-free VZV OKA at a multiplicity of infection of 0.1 plaque-forming units per cell. Cytopathic effects and significant viral antigen labeling with antibodies against VZV gpl and immediate-early (IE) protein 62 were first detected 6 to 7 days postinfection. Several observations indicated that astrocyte GFAP expression was altered and diminished as a result of VZV infection itself, thereby raising doubts about the utility of combining cell markers and viral antigenic labeling in assessing the susceptibility of neural cell types to viral infection. The down-regulation of GFAP expression by VZV appears to be mediated by early rather than late events in the viral replication cycle and may not be the result of virally induced global shut-off of host cell protein synthesis. Similar observations were made using VZV Ellen, a multipassaged, nonvaccine strain. These observations have potential in vivo implications related to histologic analysis of VZV-infected tissues and disease pathogenesis.     

Cooperation between glutathione depletion and protein synthesis inhibition against naturally occurring neuronal death

It is generally agreed that naturally-occurring neuronal death in developing animals is dependent on the synthesis of proteins. Oxidative stress, as when intracellular concentrations of free radicals are raised or when cell constituents such as membrane lipids or protein thiols are oxidized, is also involved in various types of neuronal death. In the present report, we show that the number of naturally dying retinal cells in the chick embryo can be reduced by intraocular injections of cycloheximide, an inhibitor of protein synthesis. L-buthionine-[S,R]-sulfoximine, an inhibitor of glutathione synthesis, can either enhance or diminish the cell death, depending on the conditions of treatment. Moreover, when the two inhibitors are combined, L-buthionine-[S,R]-sulfoximine potentiates the neuroprotective effects of cycloheximide. Measurements of retinal glutathione concentration and protein synthesis show the specificity of the treatments: buthionine-sulfoximine diminishes glutathione concentrations but not protein synthesis whereas cycloheximide inhibits protein synthesis without decreasing glutathione concentrations. Naturally-occurring neuronal death thus seems to involve the synthesis of proteins, and is also influenced by oxidative phenomena. Our results extend previous data in tectal-lesioned embryos, and suggest that a moderate, non-lethal oxidative stress can enhance the resistance of ganglion cells that might otherwise have died (spontaneously or following axotomy) owing to insufficient retrograde trophic support.     

Anatomical correction of the exstrophy-epispadias complex: analysis of 34 patients

OBJECTIVE: To evaluate the surgical procedures required for anatomical reconstruction of the bladder and penis in the exstrophy-epispadias complex. PATIENTS AND METHODS: All primary exstrophy-epispadias repairs carried out by one surgeon between 1987 and 1997 were reviewed. Bladder closure consisted of full extraperitoneal mobilization, transpositional omphaloplasty, drainage with ureteric and urethral catheters and immobilization with a 'frog-leg' plaster-cast or 'mermaid' dressings. Osteotomies were always performed when bladder closure was attempted after 37 h of age. Before 1990 the osteotomies were posterior vertical iliac (one patient) and subsequently anterior oblique iliac (10 patients). Pre-peritoneal herniotomies, in the absence of a clinical hernia, were included in the primary procedure after 1992. A modified Cantwell technique was used for epispadias repair and this was undertaken at a median of 16 months after bladder closure (range 6-30). RESULTS: Thirty-four patients (27 male) were reviewed; one patient had a chromosomal abnormality, a deletion in the short arm of chromosome 4. The male infants required a median of four procedures (range 2-5) for bladder closure, epispadias reconstruction and herniotomies, while the females needed a median of two (range 2-5). Complete bladder dehiscence, requiring re-closure with osteotomies, occurred in three cases (9%, two male). There were no dehiscences in the primary osteotomy group. Fistulae after epispadias repair occurred in four patients (17%). The bladder capacity increased to > 60 mL in 10 of 15 males by 36 months after epispadias repair. Only two of seven female infants attained a capacity of > 60 mL. Of the 15 infants who did not undergo herniotomy at primary closure, 13 subsequently developed inguinal hernias (one uni- and 11 bilateral) with incarceration occurring in two. Twelve infants underwent herniotomy at primary closure and six developed subsequent hernias (two uni- and four bilateral; P = 0.05) with documented incarceration in two. CONCLUSIONS: Anatomical correction of the exstrophy-epispadias complex remains challenging, but can be achieved with complication rates of < 20% for each stage. Bladder volumes large enough to permit adequate bladder neck reconstruction can be anticipated after epispadias repair in a large proportion of male infants, but remains small in female infants with low outlet resistance. Inguinal herniotomy at the time of bladder closure significantly reduces the incidence of subsequent herniation, which nevertheless remains high.     

Effect of bile/pancreatic secretions on absorption of radioactive or stable zinc. In vivo and in vitro studies

Biliary/pancreatic (B/P) secretions are a major component of endogenous secretions, and endogenously secreted Zn is a primary means of Zn homeostasis. This study examined whether B/P fluid alters the absorption/reabsorption of Zn and, in doing so, whether this contributes to homeostatic control of Zn. Animal experiments utilized rats fed 10 or 300 micrograms Zn/kg diet. An open-ended gut perfusion study in which 65Zn-labeled B/P fluid or 67Zn-labeled and digested diet found significantly decreased Zn absorption from B/P fluid. Although Zn absorption from both sources was less in animals fed diets higher in Zn, there was no interaction of treatment and diet. Further studies utilizing cultured human colon carcinoma cells (CACO-2) as in vitro models of gut enterocytes found that the presence of B/P fluid significantly decreased Zn retention and/or transport and resulted in a redistribution of cellular Zn after 1200 min of incubation. These studies show that a substance in B/P fluid can decrease the absorption of Zn and also suggest that dietary Zn and Zn associated with B/P secretions are absorbed from distinct pools. However, the lack of an interactive effect with diet, and the amount of time required to see differences in CACO-2 cells, suggest that differences in absorption are not a major contributor to Zn homeostasis.     

The Pharmacology and Therapeutic Utility of Sodium Hydroselenide

Metabolically active gasotransmitters (nitric oxide, carbon monoxide and hydrogen sulfide) are important signalling molecules that show therapeutic utility in oxidative pathologies. The reduced form of selenium, hydrogen selenide (HSe⁻/H₂Se), shares some characteristics with these molecules. The simple selenide salt, sodium hydroselenide (NaHSe) showed significant metabolic activity, dose-dependently decreasing ex vivo O₂ consumption (rat soleus muscle, liver) and transiently inhibiting mitochondrial cytochrome C oxidase (liver, heart). Pharmacological manipulation of selenoprotein expression in HepG2 human hepatocytes revealed that the oxidation status of selenium impacts on protein expression; reduced selenide (NaHSe) increased, whereas (oxidized) sodium selenite decreased the abundance of two ubiquitous selenoproteins. An inhibitor of endogenous sulfide production (DL-propargylglycine; PAG) also reduced selenoprotein expression; this was reversed by exogenous NaHSe, but not sodium hydrosulfide (NaHS). NaHSe also conferred cytoprotection against an oxidative challenge (H₂O₂), and this was associated with an increase in mitochondrial membrane potential. Anesthetized Wistar rats receiving intravenous NaHSe exhibited significant bradycardia, metabolic acidosis and hyperlactataemia. In summary, NaHSe modulates metabolism by inhibition of cytochrome C oxidase. Modification of selenoprotein expression revealed the importance of oxidation status of selenium therapies, with implications for current clinical practice. The utility of NaHSe as a research tool and putative therapeutic is discussed.     

Subcritical interlaminar crack growth in fibre composites exhibiting a risingR-curve

Subcritical crack growth behaviour has been evaluated in composite laminates based on uniaxial carbon fibres in poly(ether-ether ketone) matrices. Double cantilever beam (DCB) specimens have been employed to give mode I loading and it is first shown that the materials exhibit a risingR-curve, i.e. the value of the interlaminar fracture energy,G _IC, increases as the crack propagates through the specimens. Secondly, when a DCB specimen is held at a constant displacement, subcritical crack growth is found to occur. The velocity of the subcritical crack growth,v, has been measured using a load-relaxation technique. Hence, values of the crack velocity,v, have been obtained as a function of the strain-energy release rate,G _I applied during subcritical crack growth. Owing to the presence of theR-curve, these data have been measured at various stages during the development of theR-curve. The relationships betweenv andG _I are modelled using power-law expressions. Finally, it is considered that theR-curve behaviour is most likely caused by the fibre bridging which develops behind the crack tip as the delamination propagates through the specimen. Fibre bridging allows stress to be transferred across the crack faces, behind the advancing crack tip, and so results in a shielding of the stress field at the crack tip from the applied stress. Therefore, the expression ascertained for the relationship between the velocity,v, of subcritical crack growth and the corresponding value ofG _I has been further refined and modelled to account for the presence of fibre bridging.     

Agonist action at D2(long) dopamine receptors: ligand binding and functional assays

Clinical pathways are being introduced by hospitals to reduce costs and control unnecessary variation in care. We studied 766 inpatients to measure the impact of a perioperative clinical pathway for patients undergoing knee replacement surgery on hospital costs. One hundred twenty patients underwent knee replacement surgery before the development of a perioperative clinical pathway, and 63 patients underwent knee replacement surgery after pathway implementation. As control groups, we contemporaneously studied 332 patients undergoing radical prostatectomy (no clinical pathway in place for these patients) and 251 patients undergoing hip replacement surgery without a clinical pathway (no clinical pathway and same surgeons as patients having knee replacement surgery). Total hospitalization costs (not charges), excluding professional fees, were computed for all patients. Mean (+/-SD) hospital costs for knee replacement surgery decreased from $21,709 +/- $5985 to $17,618 +/- $3152 after implementation of the clinical pathway. The percent decrease in hospitalization costs was 1.56-fold greater (95% confidence interval 1.02-2.28) in the knee replacement patients than in the radical prostatectomy patients and 2.02-fold greater (95% confidence interval 1.13-5.22) than in the hip replacement patients. If patient outcomes (e.g., patient satisfaction) remain constant with clinical pathways, clinical pathways may be a useful tool for incremental improvements in the cost of perioperative care. Implications: Doctors and nurses can proactively organize and record the elements of hospital care results in a clinical pathway, also known as "care pathways" or "critical pathways." We found that implementing a clinical pathway for patients undergoing knee replacement surgery reduced the hospitalization costs of this surgery.     

Demonstration of the feasibility of emergency department immunization against influenza and pneumococcus

STUDY OBJECTIVE: To demonstrate the feasibility of systematic immunization against influenza and pneumococcus in a public emergency department. METHODS: This was a demonstration project conducted from October 21, 1996, through December 2, 1996, at Cook County Hospital, an inner-city hospital with a 1996 adult ED census of 120,449. Seventy-eight percent of patients are uninsured; 92% are people of color; 73% deny having a primary physician. Only 15% have emergency complaints. Nurses received standing orders that all nonemergency adult patients meeting Centers for Disease Control and Prevention criteria for high risk should be offered immunization against influenza and pneumococcus at triage. Cash prizes were offered to nurses appropriately immunizing the most patients. The date of immunization was entered into the computerized patient registration system, available to all providers within the county system. From November 4 through November 18, an extra nurse was assigned to triage to test for improvement in immunization rates. A time-motion study determined the time required per immunization on the basis of a convenience sample of 8 nurses drawn from all 3 shifts. RESULTS: Only 3% of identified high-risk patients reported previous pneumococcal immunization. Despite extreme variation in nurse performance, 2,631 patients (24% of patients triaged) were screened, and 716 high-risk patients were identified (27% of patients screened). A total of 1234 patients were immunized against influenza, and 241 patients were appropriately immunized against pneumococcus. Sixty-one percent of high-risk patients with no contraindication to influenza immunization were immunized against influenza. Thirty-five percent of high-risk patients not previously immunized against pneumococcus were immunized against pneumococcus. Immunizations per shift per triage nurse varied from 0 to 24. Median time for all activities related to immunization was 4 minutes (range, 2 to 10 minutes). There was no increase in immunization rates with the addition of an extra nurse at triage (95% confidence interval for odds ratio, .929 to 1.153). CONCLUSION: Systematic immunization against influenza and pneumococcus is both needed and feasible in a public ED. "Buy-in" by nurses is variable. Increased staffing alone does not improve immunization rates.     

Resting respiratory tract dendritic cells preferentially stimulate T helper cell type 2 (Th2) responses and require obligatory cytokine signals for induction of Th1 immunity

Consistent with their role in host defense, mature dendritic cells (DCs) from central lymphoid organs preferentially prime for T helper cell type 1 (Th1)-polarized immunity. However, the "default" T helper response at mucosal surfaces demonstrates Th2 polarity, which is reflected in the cytokine profiles of activated T cells from mucosal lymph nodes. This study on rat respiratory tract DCs (RTDCs) provides an explanation for this paradox. We demonstrate that freshly isolated RTDCs are functionally immature as defined in vitro, being surface major histocompatibility complex (MHC) II lo, endocytosishi, and mixed lymphocyte reactionlo, and these cells produce mRNA encoding interleukin (IL)-10. After ovalbumin (OVA)-pulsing and adoptive transfer, freshly isolated RTDCs preferentially stimulated Th2-dependent OVA-specific immunoglobulin (Ig)G1 responses, and antigen-stimulated splenocytes from recipient animals produced IL-4 in vitro. However, preculture with granulocyte/macrophage colony stimulating factor increased their in vivo IgG priming capacity by 2-3 logs, inducing production of both Th1- and Th2-dependent IgG subclasses and high levels of IFN-gamma by antigen-stimulated splenocytes. Associated phenotypic changes included upregulation of surface MHC II and B7 expression and IL-12 p35 mRNA, and downregulation of endocytosis, MHC II processing- associated genes, and IL-10 mRNA expression. Full expression of IL-12 p40 required additional signals, such as tumor necrosis factor alpha or CD40 ligand. These results suggest that the observed Th2 polarity of the resting mucosal immune system may be an inherent property of the resident DC population, and furthermore that mobilization of Th1 immunity relies absolutely on the provision of appropriate microenvironmental costimuli.     

Assessment of the nutritional state of dialysis patients

Obstructive sleep apnea syndrome (OSAS) has been associated with a higher than normal cardiovascular morbidity and mortality. Some OSAS patients lack the sleep-related, nocturnal decrease, or "dip," in blood pressure which is seen in normal individuals. These subjects, called "non-dippers," may be at greater risk for cardiovascular problems. We studied 40 OSAS patients (including 3 women) and 6 control subjects, all identified by polysomnography, for nocturnal blood pressure "dipping." We performed a second nocturnal polysomnogram to determine their apnea and hypopnea indices, (A + H)I, and oxygen saturation levels at the beginning of the study and then initiated 48 hours of ambulatory blood pressure monitoring, with data points collected every 30 minutes. Controls, which included one hypertensive subject, were all dippers. Nineteen OSAS subjects (48% of OSAS individuals) were systolic non-dippers and only 9 of them (22.5%) were diastolic non-dippers. We considered the following clinical variables as potential predictors of non-dipping: age, body mass index, respiratory disturbance index, years of reported loud snoring by bed partners, lowest oxygen saturation during nocturnal sleep, and percentage of sleep time spent with oxygen saturation below 90%. Multiple regression analyses indicated respiratory disturbance index as the only significant variable for systolic (p = 0.04) and diastolic (p = 0.03) blood pressure non-dipping. When we forced the following two nonsignificant variables into the model, they showed a very meager impact: number of years with reported loud snoring (p = 0.4 and p = 0.5, respectively for systolic and diastolic blood pressure non-dipping) and age (p = 0.5 and p = 0.6). The calculated model explained only a low percentage of the variance with an r2 of 0.25 and 0.26 for systolic and diastolic blood pressure non-dipping, respectively. Analysis of hypertension/normotension and dipping/non-dipping failed to show a significant relationship in the studied population. Fifty percent of the normotensive OSAS subjects were non-dippers and 43% of the hypertensive OSAS subjects were also non-dippers. We found a relationship between increasing respiratory disturbance index and increasing average 24-hour systolic blood pressure only when OSAS subjects were non-dippers and hypertensive.