Beyond survival: unraveling the adaptive mechanisms of cucurbit weeds to salt and heavy metal stress through biochemical and physiological analyses.

Salt stress and heavy metal are instigating hazard to crops, menace to agricultural practices. Single and combined stresses affecting adversely to the growth and metabolism of plants. To explore salt and heavy metal resistant plant lines as phytoremediants is a need of time. Physiological responses are main adaptive responses of the plants towards stresses. This response varies with species and ecotype as well as type and level of stress. Two cucurbit weeds from two ecotypes were selected to evaluate their physiological adaptations against independent and combined stresses of various levels of salt (NaCl) and heavy metal (NiCl2). Various physiological parameters like water potential, osmotic potential, pressure potential, CO2 assimilation rate, stomatal conductance, chlorophyll a and b, carotenoids, and production of adaptive chemicals like SOD, CAT, proteins, sugars and proline were studied. Citrullus colocynthis showed more adaptive response than Cucumis melo agrestis and desert ecotype was more successful than agricultural ecotype against stresses.

Dose-dependent acute phase response of aqueous leaf decoction of Nerium oleander in Wistar rats.

Many studies have been carried out in order to determine the toxicity of medicinal plants. The objective of this study was to compare and analyze the hepatic response against two doses of Nerium oleander, (N. oleander) “kaner” leaf decoction. Aqueous leaf decoction was injected intramuscularly into both hind limbs of male rats (200∓10g), assigned into three categories (n=4): control group with no treatment; group I, injected with 5 ml/ kg; and group II injected with 10 ml/ kg of leaf decoction, respectively. Animals were sacrificed 6 h after administration and hepato-histological changes were then observed. The decoction induced an acute phase reaction reflected by a more significant recruitment of inflammatory cells in group II than in group I and controls, as observed by histological studies. These results indicated that both doses can induce an acute-phase condition. Hence, traditional practice of medicinal plants without preliminary dose assessment must not be administered.

High energy femtosecond fiber chirped pulse amplification system with adaptive phase control.

We demonstrate increased peak power from an Yb fiber CPA system operating with strong self-phase modulation by shaping the spectral-phase of the input pulses. An adaptive control loop used feedback from the output autocorrelation. We investigated pre-compensation of both SPM phase distortion at high energies, and residual dispersion from mismatched stretcher/compressor technologies at low energies. Phase shaping resulted in improved pulse quality. When using a bulk grating stretcher, shaping increased the autocorrelation peak by a factor of 2.9, and with a fiber stretcher, shaping increased the autocorrelation peak by a factor of 3.4. High-quality 800 fs, 65 microJ recompressed pulses were produced. This technique could benefit a wide variety of fiber amplifier systems and is self-optimising for operation at both low and high pulse energies.

Supersonic radiatively cooled rotating flows and jets in the laboratory.

The first laboratory astrophysics experiments to produce a radiatively cooled plasma jet with dynamically significant angular momentum are discussed. A new configuration of wire array z pinch, the twisted conical wire array, is used to produce convergent plasma flows each rotating about the central axis. Collision of the flows produces a standing shock and jet that each have supersonic azimuthal velocities. By varying the twist angle of the array, the rotation velocity of the system can be controlled, with jet rotation velocities reaching approximately 18% of the propagation velocity.

Adaptively shaped mid-infrared pulses from a synchronously pumped optical parametric oscillator.

Adaptively shaped, sub-picosecond pulses at 3.4microm are obtained from a synchronously pumped optical parametric oscillator based on periodically poled lithium niobate. A simulated annealing algorithm is used in a learning loop to gain adaptive control of the mid-infrared idler pulse shape via shaping of a chirped near-infrared pump pulse. Both indirect control, via optimization of the signal average power, and direct control, via optimization of the two-photon absorption of the idler in an InGaAs detector, has been demonstrated. Both these optimization parameters lead to compressed idler pulses, with slightly differing pulse shapes. By optimization of the cross correlation signal in an interferometer with unequal arm lengths we are also able to deliver compressed double pulses with a variable time delay.

Risk assessment and standardized nosocomial infection rate in critically ill children.

OBJECTIVES: To develop and validate a pediatric nosocomial infection risk (PNIR) assessment model, and to compare the daily trends in risk factors between patients with nosocomial infection (cases) and without nosocomial infection (controls) in the pediatric intensive care unit (ICU). DESIGN: Prospective cohort. SETTING: A 16-bed pediatric ICU in an urban, university-affiliated, multidisciplinary, regional referral center. PATIENTS: Patients available for study included consecutive admissions to the unit between May 1, 1992, and April 30, 1993, and between May 9, 1995, and December 11, 1995. Patients from both data collection periods were pooled and randomly divided into training (70%) and validation (30%) samples. MEASUREMENTS AND MAIN RESULTS: In the logistic regression analysis using admission day data, three factors were shown to remain as independent risk factors. Invasive device use, parenteral nutrition, and the interaction between severity of illness-modified Pediatric Risk of Mortality III-24 score and postoperative care were associated with 2, 6, and 1.5 times the risk of developing nosocomial infection, respectively. This PNIR model performed well in both the training and validation samples as indicated by the goodness-of-fit test, which evaluated standardized nosocomial infection rates (observed vs. predicted nosocomial infection rates). The internal validity of the PNIR model was good. In trend analysis, severity of illness and invasive device use appear to have similar trend patterns, during the first week of pediatric ICU stay. There was no difference in any of these risk factors between cases and controls after 7 days of pediatric ICU stay. CONCLUSIONS: The PNIR assessment model incorporates intrinsic factors, such as patient severity of illness, and extrinsic factors contributing to the development of nosocomial infection in this high-risk population. The methodology using intrinsic and extrinsic factors to adjust for nosocomial infections should be taken into consideration when evaluating interhospital comparison of nosocomial infection rates, quality assessment, intervention strategies, and use of treatment modalities.

Nosocomial enterococcal infections in children.

OBJECTIVES: To identify factors that are associated with an increased risk of nosocomial enterococcal infection in children. METHODS: A matched case-control study was conducted between January 1989 and July 1993 at the Children's National Medical Center, Washington DC. One control patient for each case was identified. Control patients did not have nosocomial enterococcal infections and were matched with cases on the basis of age and time of admission closest to the case within a three-month period. Data were collected from systematic review of patient medical records. One hundred and one study patients (cases) were matched with 101 control patients. A case was defined as a patient with enterococcal infection who met the Centers for Disease Control and Prevention criteria for nosocomial infection. Microbiology methods included isolation, identification, and antimicrobial susceptibility testing of enterococci from clinical specimens. RESULTS: Risk factors associated with nosocomial enterococcal infections were determined by multiple conditional logistic regression analyses of the cases and controls. Factors identified were placement of a central line, gastrointestinal tract pathology, and administration of multiple antimicrobial agents. The median duration of antimicrobial therapy prior to diagnosis of nosocomial enterococcal infection was approximately 1 week. CONCLUSION: The incidence of nosocomial enterococcal infections in children may be controlled by limiting the number of antimicrobial agents administered to hospitalized high risk patients. The importance of our findings is relevant in an era of increasing rates of antimicrobial resistance in nosocomial enterococcal infections.

Vancomycin-resistant Enterococcus faecium colonization in children.

Nosocomial vancomycin-resistant Enterococcus (VRE) infections have been described in only small numbers of pediatric patients. In none of these studies were multivariate analyses performed to assess which factors were independent risk factors in these patients. In the present cohort study of patients admitted to our hematology/oncology unit, surveillance cultures revealed a colonization rate of 24% and all isolates were identified as Enterococcus faecium. Risk factors associated with colonization with VRE identified by multiple logistic regression analysis included young age and chemotherapy with antineoplastic agents, cefotaxime, vancomycin, and ceftazidime. A molecular epidemiological tool, pulsed-field gel electrophoresis, was used to determine the relatedness of the VRE isolates detected. DNA analysis by this method identified two major clusters of VRE isolates. Young children with gastrointestinal colonization with VRE, without evidence of clinical infection, can serve as a reservoir for the spread of VRE.

Risk factors for nosocomial infection in critically ill children: a prospective cohort study.

OBJECTIVE: To identify factors in pediatric intensive care unit (ICU) patients that are associated with an increased risk of nosocomial infections. DESIGN: A prospective, 1-yr cohort study. SETTING: A 16-bed pediatric ICU in a multidisciplinary, regional referral center. SUBJECTS: All patients admitted to the pediatric ICU. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: The primary outcome variable was the development of nosocomial infection. Out of 945 consecutive admissions, 75 patients developed 96 nosocomial infections. The most frequent infection sites were the lower respiratory tract (35%), the bloodstream (21%), and the urinary tract (21%). The most common organisms isolated were Gram-negative bacteria (53%, Gram-positive bacteria (27%), and fungi (9%). Variables significantly associated with the development of nosocomial infections included age, weight, Pediatric Risk of Mortality (PRISM) score, device utilization ratio, antimicrobial therapy, histamine-2 (H2) receptor blocker use, immune status, parenteral nutrition, and length of stay. When combined in a multivariate logistic regression model, the significant variables were operative status, PRISM score, device utilization ratio, antimicrobial therapy, parenteral nutrition, and length of stay before the onset of infection. The area under the receiver operating characteristic curve was 0.868. At a probability of 0.15, the sensitivity was 66.67%, and the specificity was 87.82%. CONCLUSIONS: Patients at risk for developing nosocomial infection can be identified using a multivariate logistic regression model with a high degree of sensitivity and specificity. These data indicate that institutional nosocomial rates need to be adjusted for risk factors. This model could help target patients at high risk for developing nosocomial infections for preventive strategies.

Nosocomial adenovirus infection: molecular epidemiology of an outbreak.

Nosocomial transmission of adenovirus type 3 associated with fatalities in infants has not been frequently reported. This report describes the nosocomial spread of adenovirus types 2 and 3 among infants with bronchopulmonary dysplasia in a chronic (transitional) care facility. The index case developed pneumonia with a clinical deterioration in respiratory status 8 days after admission. Within the next 10 to 30 days 9 other infants and 2 health care personnel became ill with respiratory symptoms. Three of these 10 infants had progressive respiratory failure and 2 of them died. All of these infants had underlying chronic lung disease of bronchopulmonary dysplasia. The overall attack rate was 30% (10 of 33). Further spread of adenovirus was prevented by using barrier precautions and masks while performing tracheostomy care. Adenovirus isolates were serotyped as Ad3 in 4 patients and 1 staff member, as Ad2 in 3 patients, and as a combination of Ad2 and Ad3 in 1 patient. Two fatalities were associated with Ad3 infection. Three isolates from 2 patients and 1 staff member were not available for typing. Restriction endonuclease analysis was performed on all of these isolates of Ad3 and Ad2. There was no genetic heterogeneity in the isolates, suggesting a common source.

Time-resolved fluoroimmunoassay for enteric adenoviruses using the europium chelator 4,7-bis(chlorosulfophenyl)-1,10-phenanthroline-2,9-dicarboxylic acid.

A time-resolved fluoroimmunoassay (TR FIA) was developed for the direct detection of adenovirus types 40 (Ad40) and 41 (Ad41) in stool specimens by using a monoclonal antibody (5D8/2C2) which recognizes both Ad40 and Ad41 but does not cross-react with other adenovirus serotypes. In this assay, the detector antibody is biotinylated directly rather than labeled with europium, and the fluorescent signal is generated on a solid phase in the presence of excess europium (Eu3+). The strength of the signal is dependent on the amount of a Eu3+ chelator [4,7-bis(chlorosulfophenyl)-1,10-phenanthroline-2,9-dicarboxylic acid (BCPDA)]-streptavidin complex bound by the biotinylated detector antibody (5D8/2C2). In a pilot study with 41 specimens, this TR FIA demonstrated a maximum sensitivity and specificity of 88% compared with SmaI restriction analysis of adenovirus isolates from the same specimens. TR FIA using the europium chelator BCPDA represents a feasible approach for the direct identification of specific adenovirus serotypes in stool specimens.

Outbreak of parainfluenza virus type 3 in a neonatal nursery.

Human parainfluenza type 3 is the most common cause of bronchiolitis and pneumonia after respiratory syncytial virus. In a recent outbreak of nosocomial respiratory illness in a neonatal intensive care unit, parainfluenza type 3 virus was isolated in 6 of 17 neonates cultured (5 symptomatic patients and 1 asymptomatic patient). Eighteen of 52 nursing personnel had been ill during the previous week and concomitantly, with cough and nasal congestion. These personnel and all patient care givers were asked to submit nasopharyngeal cultures. Parainfluenza type 3 virus was recovered from 2. Glove and gown barriers and cohorting of infant patients limited further spread of the disease.

Enteric adenovirus infection and childhood diarrhea: an epidemiologic study in three clinical settings.

During a 2-year prospective study of gastroenteritis in children less than 2 years of age, the role of enteric adenovirus as a cause of infantile diarrhea was examined in three clinical settings in a case-control fashion. Using a monoclonal antibody-based enzyme-linked immunosorbent assay with specificity for adenovirus serotypes 40 and 41, enteric adenovirus was identified in 10 of 246 episodes of diarrhea in outpatients (4.1%), 13 of 211 children admitted to the hospital with diarrhea (6.2%), and 5 of 81 children in whom nosocomial diarrhea developed (6.2%), making this agent the third most commonly identified etiologic agent of diarrheal disease. Asymptomatic infections were uncommon (5 of 372 control subjects, or 1.3%) and were seen most frequently in the nosocomial setting. Cases occurred in every calendar month except March and April of each year. A syndrome of watery diarrhea of longer duration compared with other patients with diarrhea (mean 5.4 vs 3.8 days, P = .01), associated with vomiting and dehydration, was present in most cases. Compared with patients with rotavirus, patients were as likely to experience fever and dehydration and more likely to vomit. Household contact with gastroenteritis, often with a child 2 to 5 years of age, was a predisposing factor. It was concluded that enteric adenovirus is an important cause of infantile diarrhea in Baltimore children. Although far less common than rotavirus, this agent was associated with diarrheal illnesses that were at least as severe as those seen with rotavirus.

Monoclonal antibody enzyme-linked immunosorbent assay for specific identification and typing of subgroup F adenoviruses.

Monoclonal antibody specific for subgroup F enteric adenoviruses (EAds) was prepared by fusing P3-NS1/Ag4-1 mouse myeloma cells with lymphocytes from BALB/c mice immunized with G1105, an adenovirus type 41 (Ad41) strain. Monoclone 3F11/2H9, which specifically recognized Ad41, was successfully used as detector antibody in an enzyme-linked immunosorbent assay (ELISA). Additionally, previously prepared monoclones 5D8/2C2 and 2H6/1E11, recognizing Ad40 plus Ad41 and Ad40 alone, respectively, were used to study stool and/or tissue culture specimens from 106 patients with adenovirus-positive gastroenteritis. By ELISA, 91 had EAds (22 were Ad40 and 69 were Ad41) and 15 had non-EAds. ELISA results were in concordance with restriction endonuclease results for 38 of 39 specimens, with dot blot data for 19 of 20 specimens, and with neutralization test results for 74 of 78 specimens. ELISA was at least 10-fold more sensitive than direct electron microscopy was for the detection of EAds in stool specimens.

Development and application of monoclonal antibodies for specific detection of human enteric adenoviruses.

Monoclonal antibodies were prepared against enteric adenovirus by fusing P3-NS1/-Ag4-1 mouse myeloma cells with lymphocytes from BALB/c mice immunized with enteric adenovirus 40 (Ad40) G2297. Of the several putative clones secreting antibodies to adenovirus, five were found to react specifically to the enteric adenovirus. The specificity of two of these monoclones which recognize a single antigen of a molecular size of 17 kilodaltons was evaluated against 78 clinical isolates. One monoclone (5D8/2C2) reacted with both Ad40 and Ad41, and the other monoclone (2H6/C11) recognized Ad40 only in an enzyme-linked immunosorbent assay (ELISA). These ELISA results correlated well with those of the specific neutralization test or DNA restriction endonuclease analysis or both. The use of this rapid ELISA with these monoclones will find applications in the diagnosis of enteric adenovirus and should facilitate the epidemiologic studies of enteric adenovirus gastroenteritis.