Bloodstream infections in neonates with central venous catheters in three tertiary neonatal intensive care units in Pune, India.

BACKGROUND: Neonates admitted to the neonatal intensive care unit (NICU) are at risk for healthcare-associated infections, including central line-associated bloodstream infections. We aimed to characterize the epidemiology of bloodstream infections among neonates with central venous catheters admitted to three Indian NICUs. METHODS: We conducted a prospective cohort study in three tertiary NICUs, from May 1, 2017 until July 31, 2019. All neonates admitted to the NICU were enrolled and followed until discharge, transfer, or death. Cases were defined as positive blood cultures in neonates with a central venous catheter in place for greater than 2 days or within 2 days of catheter removal. RESULTS: During the study period, 140 bloodstream infections were identified in 131 neonates with a central venous catheter. The bloodstream infection rate was 11.9 per 1000 central line-days. Gram-negative organisms predominated, with 38.6% of cases caused by Klebsiella spp. and 14.9% by Acinetobacter spp. Antimicrobial resistance was prevalent among Gram-negative isolates, with 86.9% resistant to third- or fourth-generation cephalosporins, 63.1% to aminoglycosides, 61.9% to fluoroquinolones, and 42.0% to carbapenems. Mortality and length of stay were greater in neonates with bloodstream infection than in neonates without bloodstream infection (unadjusted analysis, p < 0.001). CONCLUSIONS: We report a high bloodstream infection rate among neonates with central venous catheters admitted to three tertiary care NICUs in India. Action to improve infection prevention and control practices in the NICU is needed to reduce the morbidity and mortality associated with BSI in this high-risk population.

Plant size, latitude, and phylogeny explain within-population variability in herbivory.

Interactions between plants and herbivores are central in most ecosystems, but their strength is highly variable. The amount of variability within a system is thought to influence most aspects of plant-herbivore biology, from ecological stability to plant defense evolution. Our understanding of what influences variability, however, is limited by sparse data. We collected standardized surveys of herbivory for 503 plant species at 790 sites across 116° of latitude. With these data, we show that within-population variability in herbivory increases with latitude, decreases with plant size, and is phylogenetically structured. Differences in the magnitude of variability are thus central to how plant-herbivore biology varies across macroscale gradients. We argue that increased focus on interaction variability will advance understanding of patterns of life on Earth.

Fatal leukemia in interleukin 15 transgenic mice follows early expansions in natural killer and memory phenotype CD8+ T cells.

Inflammation likely has a role in the early genesis of certain malignancies. Interleukin (IL)-15, a proinflammatory cytokine and growth factor, is required for lymphocyte homeostasis. Intriguingly, the expression of IL-15 protein is tightly controlled by multiple posttranscriptional mechanisms. Here, we engineered a transgenic mouse to overexpress IL-15 by eliminating these posttranscriptional checkpoints. IL-15 transgenic mice have early expansions in natural killer (NK) and CD8+ T lymphocytes. Later, these mice develop fatal lymphocytic leukemia with a T-NK phenotype. These data provide novel evidence that leukemia, like certain other cancers, can arise as the result of chronic stimulation by a proinflammatory cytokine.

Misexpression of IGF-I in the mouse lens expands the transitional zone and perturbs lens polarization.

Insulin-like growth factor-I (IGF-I) has been implicated as a regulator of lens development. Experiments performed in the chick have indicated that IGF-I can stimulate lens fiber cell differentiation and may be involved in controlling lens polarization. To assess IGF-I activity on mammalian lens cells in vivo, we generated transgenic mice in which this factor was overexpressed from the alphaA-crystallin promoter. Interestingly, we observed no premature differentiation of lens epithelial cells. The pattern of lens polarization was perturbed, with an apparent expansion of the epithelial compartment towards the posterior lens pole. The distribution of immunoreactivity for MIP26 and p57(KIP2) and a modified pattern of proliferation suggested that this morphological change was best described as an expansion of the germinative and transitional zones. The expression of IGF-I signaling components in the normal transitional zone and expansion of the transitional zone in the transgenic lens both suggest that endogenous IGF-I may provide a spatial cue that helps to control the normal location of this domain.

Regulation of melatonin 1a receptor signaling and trafficking by asparagine-124.

Melatonin is a pineal hormone that regulates seasonal reproduction and has been used to treat circadian rhythm disorders. The melatonin 1a receptor is a seven- transmembrane domain receptor that signals predominately via pertussis toxin-sensitive G-proteins. Point mutations were created at residue N124 in cytoplasmic domain II of the receptor and the mutant receptors were expressed in a neurohormonal cell line. The acidic N124D- and E-substituted receptors had high-affinity (125)I-melatonin binding and a subcellular localization similar to the neutral N124N wild-type receptor. Melatonin efficacy for the inhibition of cAMP by N124D and E mutations was significantly decreased. N124D and E mutations strongly compromised melatonin efficacy and potency for inhibition of K(+)-induced intracellular Ca(++) fluxes and eliminated control of spontaneous calcium fluxes. However, these substitutions did not appear to affect activation of Kir3 potassium channels. The hydrophobic N124L and N124A or basic N124K mutations failed to bind (125)I-melatonin and appeared to aggregate or traffic improperly. N124A and N124K receptors were retained in the Golgi. Therefore, mutants at N124 separated into two sets: the first bound (125)I-melatonin with high affinity and trafficked normally, but with reduced inhibitory coupling to adenylyl cyclase and Ca(++) channels. The second set lacked melatonin binding and exhibited severe trafficking defects. In summary, asparagine-124 controls melatonin receptor function as evidenced by changes in melatonin binding, control of cAMP levels, and regulation of ion channel activity. Asparagine-124 also has a unique structural effect controlling receptor distribution within the cell.

Differential expression of alpha A- and alpha B-crystallin during murine ocular development.

PURPOSE: To compare the temporal and spatial expression patterns of alpha A- and alpha B-crystallin mRNA during ocular development. METHODS: Tissue samples from embryonic day 9.5 (E9.5) through postnatal day 14 were collected from FVB/N strain mice. The specimens were fixed in paraformaldehyde, histologically processed, and assayed for alpha A- and alpha B-crystallin mRNA expression by in situ hybridization. RESULTS: During ocular development, alpha B-crystallin transcripts are present in the lens placode at E9.5. Transcripts of alpha A-crystallin are first observed in the lens cup at E10 to 10.5. During subsequent development of the lens, alpha A crystallin transcripts are most abundant in the fiber cells, and alpha B crystallin mRNA is preferentially expressed in epithelial cells. Transcripts of alpha A-crystallin were detected only in the lens. In contrast, alpha B-crystallin transcripts are present in retinal pigment epithelium, optic nerve, extraocular muscle, iris, ciliary body, cornea, and several nonocular sites, such as heart and nasal epithelium. CONCLUSIONS: Transcription of alpha B-crystallin precedes the expression of alpha A-crystallin during murine ocular development. Furthermore, the patterns of alpha A- and alpha B-crystallin expression in the lens are distinctive: alpha A is upregulated and alpha B is downregulated during prenatal fiber cell differentiation. These results indicate that the alpha-crystallin genes are not identically regulated either within or outside the lens.

A transgenic animal model of osmotic cataract. Part 1: over-expression of bovine Na+/myo-inositol cotransporter in lens fibers.

PURPOSE: Intracellular osmotic stress is believed to be linked to the advancement of diabetic cataract. Although the accumulation of organic osmolytes (myo-inositol, sorbitol, taurine) is thought to protect the lens by maintaining osmotic homeostasis, the physiologic implication of osmotic imbalance (i.e., hyperosmotic stress caused by intracellular over-accumulation of organic osmolytes) on diabetic cataract formation is not clearly understood. Studies from this laboratory have identified several osmotic compensatory mechanisms thought to afford the lens epithelium, but not the lens fibers, protection from water stress during intervals of osmotic crisis. This model is founded on the supposition that the fibers of the lens are comparatively more susceptible to damage by osmotic insult than is the lens epithelium. To test this premise, several transgenic mouse lines were developed that over-express the bovine sodium/myo-inositol cotransporter (bSMIT) gene in lens fiber cells. METHODS: Of the several transgenic mouse lines generated, two, MLR14 and MLR21, were analyzed in detail. Transgenic mRNA expression was analyzed in adult and embryonic transgenic mice by a coupled reverse transcriptase-polymerase chain reaction (RT-PCR) and in situ hybridization on embryonic tissue sections, respectively. Intralenticular myo-inositol content from individual mouse lenses was quantified by anion exchange chromatography and pulsed electrochemical detection. Ocular histology of embryonic day 15.5 (E15.5) embryos from both transgenic (TG) families was analyzed and compared to their respective nontransgenic (NTG) littermates. RESULTS: Both RT-PCR and in situ hybridization determined that transgene expression was higher in line MLR21 than in line MLR14. Consistent with this, intralenticular myo-inositol from MLR21 TG mice was markedly higher compared with NTG littermates or MLR14 TG mice. Histologic analysis of E15.5 MLR21 TG embryos disclosed a marked swelling in the differentiating fibers of the bow region and subcapsular fibers of the central zone, whereas the lens epithelium appeared morphologically normal. The lenticular changes, initiated early during lens development in TG MLR21 embryos, result in severe bilateral nuclear cataracts readily observable in neonates under normal rearing and dietary conditions. In contrast, TG MLR14 pups reared under standard conditions produced no lens opacity. CONCLUSIONS: Lens fiber swelling and related cataractous outgrowth positively correlated to the degree of lens bSMIT gene expression and intralenticular myo-inositol content. The affected (i.e., swollen) lens fibers appeared to be unable to cope with the water stress generated by the transgene-induced over-accumulation of myo-inositol and, as a result of this inability to osmoregulate, suffered osmotic damage due to water influx.

Diffuse uterine leiomyomatosis: a case study with pregnancy complicated by intrapartum hemorrhage.

Diffuse leiomyomatosis of the uterus is a rarely reported condition which has been implicated as a cause of infertility and menorrhagia. We report the first documented case of pregnancy in the presence of this disorder. The course was complicated by cervical incompetence, spontaneous premature rupture of membranes, delivery by cesarean section, and intrapartum hemorrhage necessitating hysterectomy. The literature is reviewed and the clinical significance of this lesion discussed. Finally, speculations are made on the nature of this disorder.

Behavioral and neural consequences of prenatal exposure to nicotine.

OBJECTIVE: To review evidence for the neurodevelopmental effects of in utero exposure to nicotine. Concerns about long-term cognitive and behavioral effects of prenatal exposure to nicotine arise from reports of increased rates of disruptive behavioral disorders in children whose mothers smoked during pregnancy. The relatively high rate of tobacco smoking among pregnant women (25% of all pregnancies in the U.S.) underlines the seriousness of these concerns. METHOD: This review examines the largest and most recent epidemiological and clinical studies that investigated the association of prenatal nicotine exposure with health, behavioral, and cognitive problems. Because of the numerous potential confounding variables in human research, findings from animal studies, in which environmental factors are strictly controlled, are also discussed. Finally, neural and molecular mechanisms that are likely to underlie neurodevelopmental disruptions produced by prenatal nicotine exposure are outlined. RESULTS: A dose-response relationship between maternal smoking rates and low birth weight (potentially associated with lower cognitive ability) and spontaneous abortion is consistently found, whereas long-term developmental and behavioral effects in the offspring are still controversial, perhaps because of the difficulty of separating them from other genetic and environmental factors. Despite the wide variability of experimental paradigms used in animal studies, common physical and behavioral effects of prenatal exposure to nicotine have been observed, including low birth weight, enhanced locomotor activity, and cognitive impairment. Finally, disturbances in neuronal pathfinding, abnormalities in cell proliferation and differentiation, and disruptions in the development of the cholinergic and catecholaminergic systems all have been reported in molecular animal studies of in utero exposure to nicotine. CONCLUSIONS: Prenatal exposure to nicotine may lead to dysregulation in neurodevelopment and can indicate higher risk for psychiatric problems, including substance abuse. Knowledge of prenatal exposure to nicotine should prompt child psychiatrists to closely monitor at-risk patients.

[125I]Vasoactive intestinal peptide binding in rodent suprachiasmatic nucleus: developmental and circadian studies.

The suprachiasmatic nucleus (SCN) of rat and hamster have been studied extensively and shown to play critical roles in circadian rhythmicity. [125I]Vasoactive intestinal peptide (VIP) binding levels are high in the rat SCN, suggesting that VIP receptors may be an important component of SCN function. In contrast to previously demonstrated diurnal variations in VIP immunoreactivity and VIP mRNA, the present study found [125I]VIP binding to be stable across the light-dark cycle in both rat and hamster SCN. High [125I]VIP labeling appeared to be coextensive with the rat SCN but extended somewhat beyond the cytoarchitectonic boundaries of the hamster SCN. Binding density in hamster SCN was slightly higher than in rat. In the developing rat SCN, [125I]VIP binding levels distinguished the SCN on embryonic day 18, and appeared to increase to postnatal day 10 before declining to adult levels. The early presence of [125I]VIP binding suggests possible involvement of VIP receptors in fetal entrainment of circadian rhythms.

The determination of nadolol in biological samples using high-performance liquid chromatography.

A method has been developed for the determination of nadolol in biological samples by reversed-phase high-performance liquid chromatography with fluorimetric detection. The method has been applied to plasma, serum and urine samples, which are prepared by extraction with diethyl ether-dichloromethane (5:2,v/v), evaporation of the organic solvent, and dissolution of the resultant residue in the chromatographic eluent. The sample is then subjected to chromatography on a C(18)-silica column, with an eluent of water-acetonitrile-triethylamine (800:200:1,v/v) adjusted to pH 3.0 with orthophosphoric acid. A single point external standard is used for quantitation. The working ranges were 1-400 ng/ml for plasma/serum, and 0.1-40 mug/ml for urine, although a detection limit of 0.1 ng/ml appears to be readily attainable. The sample size was 0.5 ml, and for both types of sample the method showed good correlation with a previously published fluorimetric method (for plasma, r = 0.9544, n = 70; for urine, r = 0.9919, n = 35).

LC studies on the potential interaction of paraben preservatives with sorbitol and glycerol.

Pharmaceutical formulations often contain one or more paraben preservatives in conjunction with a polyol such as sorbitol or glycerol. In one of these experimental formulations a number of unknown polar peaks have been detected near the solvent front by reversed-phase LC. These degradation products were not attributable to the active drug component or a hydrolysis product. The possibility of an interaction between the polyols and paraben preservatives has been explored using a three-variable, two-level, factorial design to determine the relative significance of the factors involved in the formation of these unknown peaks. The factors examined were pH, temperature and the ratio of polyol to paraben. This study has shown that pH and temperature are key factors affecting the formation of these unknown peaks. On the basis of these results suitable conditions can be suggested for minimizing the production of these unknown peaks. It seems clear that a number of pharmaceutical formulations containing a polyol and a paraben would present potential problems for assay validation on storage owing to the formation of these degradation products, particularly if the drug component is polar and elutes near the solvent front.

Placebo cigarettes in smoking research.

This review outlines the development and use of placebo cigarettes in smoking research. Research on effects of smoking has been disadvantaged by the lack of an adequate placebo condition. Recently, tobacco-based denicotinized cigarettes have been used in smoking research to distinguish effects of smoking due to the delivery of nicotine, other components of tobacco smoke, and the sensory process of smoking. Placebo cigarettes do not increase heart rate and blood pressure or produce electroencephalogram changes ordinarily associated with nicotine. However, placebo cigarettes reduce subjective measures of tobacco craving, desire to smoke, and tobacco withdrawal. These findings indicate that the effects of cigarette smoking are dependent on the delivery of nicotine, tar, other compounds of tobacco smoke, and the sensory stimuli. The next generation of research may begin to investigate the mechanisms that modulate these placebo effects.

Acute limb ischemia.

Acute ischemia of the extremity may be due to arterial occlusion from spontaneous thrombosis, embolus, arterial bypass graft thrombosis, trauma, or spasm. The presence of occlusion or stenosis can be determined noninvasively with the use of duplex Doppler ultrasonography. Most patients will require arteriography prior to thrombolytic or surgical therapy. New techniques, such as percutaneous aspiration thrombolectomy, expand the role of radiologic percutaneous therapy of the acutely ischemic limb. Prompt diagnosis and therapy are required to avoid limb loss or systemic metabolic complications from reperfusion of a dying limb.

African-American teen smokers: issues to consider for cessation treatment.

Previous reports have indicated ethnic differences in both tobacco-related morbidity and treatment outcome for smoking cessation among adults. We assessed smoking-related characteristics in African-American and non-African American teenagers applying to a cessation trial. 115 teens (15.9 +/- 1.8 years, 68% females, 27% African-American) responded via telephone to media ads. Self-reported sociodemographic, medical and smoking-related data were obtained to determine pre-eligibility for a full intake screen prior to trial participation. Compared to non-African American, African American teen applicants were older (16.4 +/- 1.7 years versus 15.6 +/- 1.6; p = 0.015), had lower Fagerström Test for Nicotine Dependence (FTND) scores (5.3 +/- 2.3 versus 6.1 +/- 1.8; p = 0.018, ANOVA controlling for age) and smoked fewer cigarettes on the weekend (27 +/- 16 versus 38 +/- 17; p = 0.001). African American teens reported similar duration of smoking (3.3 +/- 1.4 versus 3.1 +/- 1.5 years) and time elapsed between first cigarette ever smoked and daily smoking (0.7 +/- 0.9 versus 0.6 +/- 0.7 years). African American and non-African American teens had similar motivation to quit scores and frequency of reported health problems (e.g., asthma, psychiatric conditions). These data suggest that cessation treatment programs designed for African American youth should include lower Fagerstrom-defined levels, and possibly other criteria for tobacco dependence. These observations also highlight the importance of ethnocultural issues in treatment research programs.

Duplex sonography of the carotid arteries.

Duplex sonography is the best noninvasive modality for investigation of possible carotid artery stenosis. By using the above described techniques, almost all significant stenoses can be detected and categorized correctly. Knowledge of common pitfalls in the performance and interpretation of the examination is essential to avoid misdiagnosis. Color imaging is a helpful addition to conventional duplex imaging, but is not essential to the performance of high-quality examinations.