This study documents the colonization of Staphylococcus aureus (SA), Streptococcus pneumoniae (SP) and specific resistant forms of these organisms among healthy children and identifies risk factors associated with these pathogens. Prospective point prevalence survey of nasopharyngeal specimens were obtained from 291 healthy children seeking routine well-child care at a university-based ambulatory paediatric clinic in a large urban city in the United States. A total of 291 children less than 5 years were enrolled during a 1-year period. Fifty-four (18.6%) were colonized with SA and 47 (16.2%) were colonized with SP. Among the 54 SA isolates, five (9.2%) were methicillin resistant (MRSA) and among the SP isolates, three (6.4%) were intermediate to penicillin (DRSP). Eighty per cent of all children enrolled reported no underlying medical condition. Care outside their home was more common among colonized (40.8%, 40/98) than non-colonized children (25.4%, 49/193), P=0.007. Healthy children from households of four or more people were also more likely to be colonized. The colonization rate of SA and SP among healthy children is consistent with what has been reported in the literature. The prevalence of MRSA and DRSP among healthy children colonized with SA or SP is low in this population of children attending a university-based ambulatory care centre in the United States.

Trimethoprim and sulfamethoxazole (Bactrim r) is a widely used antibiotic combination effective against a broad spectrum of microbial organisms. There are reports of neutropenia developing during even brief periods of oral therapy, particularly in individuals with either folate deficiency or increased folate requirements. We have investigated the effects of these drugs on circulating granulocyte precursors (CFU-C) from normal donors and the mechanism of inhibition on granulopoiesis using an in vitro CFU-C assay. In 12 healthy adults, the number of circulating granulocytes and granulocyte progenitors was not significantly altered by a 5-day course of therapy. However, in experiments that simulated the in vivo condition of folate deficiency (folate-free cultures were prepared with cells harvested from normal donors), trimethoprim (8 micrograms/ml) resulted in a 47% decrease in the total number of colonies; this inhibitory effect was prevented when 100 ng of folinic acid was also added to the culture. Sulfamethoxazole (40 micrograms/ml) had no discernible effect on granulopoiesis. The combination of 8 micrograms/ml of trimethoprim and 40 micrograms/ml of sulfamethoxazole resulted in a 52% decrease in the number of colonies generated and this inhibition was again prevented by folinic acid. Our results suggest that the neutropenia occasionally observed in patients treated with trimethoprim-sulfamethoxazole is due to the inhibitory effects on granulopoiesis by trimethoprim, namely its antifolate action, which is reversed by folinic acid. Based on these studies, in patients with either folate deficiency or increased folate requirements, trimethoprim-sulfamethoxazole should be used with caution.

During myocardial ischemia/reperfusion (I/R), the generation of reactive oxygen species (ROS) contributes to post‐reperfusion cardiac injury and contractile dysfunction. Activation of protein kinase C epsilon (PKC ɛ) during I/R has been shown to increase ROS release, in part, by its stimulation of increased uncoupled endothelial nitric oxide synthase activity. We hypothesize that using a cell permeable PKC ɛ peptide inhibitor (PKC ɛ‐) (N‐myr‐EAVSLKPT, MW=1054 g/mol, 10μM or 20μM) will improve post‐reperfused cardiac function and attenuate infarct size compared to untreated controls in isolated perfused rat hearts subjected to I(30 min)/R(90 min). Male Sprague‐Dawley rats (275–325 g) were anesthetized with sodium pentobarbital (60 mg/kg) and anticoagulated with heparin 1000 units IP. PKC ɛ‐was dissolved in Krebs' buffer and infused during the first 10 min of reperfusion. PKC ɛ‐treated hearts exhibited significant improvement in post‐reperfused cardiac function at 90 min in the maximal rate of left ventricular developed pressure (+dP/dtmax): 56±5%; n=6 (10μM) and 46±3%; n=4 (20μM) compared to untreated controls (n=6) which only recovered to 32±5% of baseline values for +dP/dtmax respectively (p<0.05). Furthermore, PKC ɛ‐treated hearts showed significant reduction in infarct size of 27±2% (10μM) and 28 ±2% (20μM) compared to untreated control I/R hearts, 40±3% (p<0.05). The results suggest that PKC ɛ‐is effective in improving cardiac function and reducing infarct size and is a putative treatment that could aid in clinical myocardial infarction/organ transplantation patient recovery.Support or Funding InformationThis study was supported by the Center for Chronic Disorders of Aging, the Division of Research and the Department of Bio‐Medical Sciences at Philadelphia College of Osteopathic Medicine.

Ischemia‐reperfusion (I/R) injury mediated by excessive reactive oxygen species (ROS) is a well‐known phenomenon causing paradoxical myocardial damage after cardio‐angioplasty, coronary bypass, or organ transplantation following ischemic injury. Protein kinase C beta II isoform (PKCβII) inhibition using a cell‐permeable myristic acid (myr‐) conjugated PKCβII peptide inhibitor (N‐myr‐SLNPEWNET; myr‐PKCβII−) given at reperfusion significantly attenuated ROS release in previous animal I/R studies. However, prior studies did not explore the possibility that myristic acid conjugation itself contributes to the attenuation of I/R injury. We hypothesize that myristic acid conjugation is not responsible for attenuation of ROS‐induced I/R damage and that myr‐PKCβII− will reduce infarct size and improve post‐reperfused cardiac function compared to scrambled myr‐PKCβII− peptide (N‐myr‐WNPESLNTE; myr‐PKCβII‐scram), myr‐PKCβII activator peptide (N‐myr‐SVEIWD; myr‐PKCβII+), and plasma controls. Hearts isolated from male Sprague‐Dawley rats (~300g) were subjected to 30 min of global ischemia and myr‐PKCβII− (20μM), myr‐PKCβII+ (20μM), myr‐PKCβII‐scram (20μM), or plasma (control) was given at initial reperfusion during the first five minutes. Thereafter, Krebs’ buffer was reperfused into hearts at a constant pressure (80 mmHg) throughout the remainder of reperfusion (50 min). Left ventricular (LV) cardiac function indices were measured using a pressure transducer, and infarct size of frozen post‐reperfused hearts was determined using 1% triphenyltetrazolium chloride staining comparing infarcted tissue vs. total tissue weight. Data were evaluated using ANOVA with Bonferroni‐Dunn post‐hoc analysis. Myr‐PKCβII‐significantly improved both post‐reperfused cardiac relaxation function indices compared to all groups (p<0.05). LV end diastolic pressure (LVEDP; mmHg) and the maximal rate of decline of LVEDP (mmHg/s) at 50 min post‐reperfusion significantly improved with myr‐PKCβII− (41±5 and 1088±84; n=16) compared to plasma‐control (61±4 and 731±95; n=14), myr‐PKCβII+ (58±4 and 716±84; n=13), or myr‐PKCβII‐scram (68±1 and 451±78; n=8) hearts. Additionally, myr‐PKCβII− significantly reduced infarct size (%) to 13±2 compared to either plasma‐control (24±4) or myr‐PKCβII‐scram (24±2; both p<0.05), whereas myr‐PKCβII+ (21±3) did not differ significantly from myr‐PKCβII‐scram or plasma‐control. Results suggest that myr‐conjugation is not responsible for the cardioprotective effects observed with myr‐PKCβII− in I/R injury. Myr‐PKCβII− may be an effective therapeutic to improve clinical outcomes after coronary bypass, cardio‐angioplasty, or organ transplantation. Support or Funding Information This research was supported by the Division of Research, Department of Biomedical Sciences, and the Center for Chronic Disorders of Aging at Philadelphia College of Osteopathic Medicine. Current research license is supported by Young Therapeutics, LLC. lindonyo@pcom.edu.

Reactive oxygen species (ROS) induced ischemia-reperfusion (I/R) injury is a phenomenon causing paradoxical myocardial damage after cardio-angioplasty, coronary bypass and organ transplantation. Previous studies show that a cell-permeable myristic acid (myr-) conjugated PKCβII peptide inhibitor given at reperfusion prevents PKCβII translocation (N - myr-SLNPEWNET; myr-PKCβII-) and significantly attenuates ROS mediated I/R injury. We included a scrambled myr-PKCβII- (N-myr-WNPESLNTE; myr-PKCβII-scram) to examine the effects of myr separately. We hypothesize that myr-PKCβII- will improve and myr-PKCβII activator peptide (N-myr-SVEIWD; myr-PKCβII+) will exacerbate infarct size and post-reperfused cardiac function compared to myr-PKCβII-scram and untreated controls. Hearts isolated from male Sprague-Dawley rats (~300g) were perfused with Krebs’ buffer at a constant pressure of 80mmHg and subjected to 30 min of global ischemia and 50 min reperfusion. Myr-PKCβII-, myr-PKCβII+, myr-PKCβII-scram (all 20μM), or untreated control were given during the first five minutes of reperfusion. Left ventricular (LV) dP/dt max and dP/dt min (mmHg/s) were measured using a pressure transducer, and infarct size was determined using 1% triphenyltetrazolium chloride staining comparing infarcted tissue vs. total tissue weight. Data were evaluated using ANOVA with Student-Newman-Keuls post-hoc analysis. Myr-PKCβII- (n=17) significantly improved LV dP/dt max and dP/dt min to 1535±107 and 1063±83 at 50 min post-reperfusion compared to untreated control (815±107 and 722±89; n=15); myr-PKCβII-scram (513±78 and 433±66; n=12), and myr-PKCβII+ (860±118 and 694±81; n=14) (all p<0.05). Myr-PKCβII- significantly reduced infarct size (%) to 13±2 compared to untreated control (24±4); myr-PKCβII-scram (22±2), and myr-PKCβII+ (21±3) (all p<0.05). Unexpectedly, myr-PKCβII-scram significantly depressed post-reperfused LV dP/dt max and LV dP/dt min compared to untreated control and other treated groups (p<0.05). Results suggest that myr-PKCβII- exerted significant cardioprotective effects compared to untreated controls, myr- PKCβII+ and myr-PKCβII-scram and would improve clinical outcomes after cardio-angioplasty or organ transplantation.