A randomized phase 2 study of MK-2206 versus everolimus in refractory renal cell carcinoma.

Background: Activation of the phosphoinisitide-3 kinase (PI3K) pathway through mutation and constitutive upregulation has been described in renal cell carcinoma (RCC), making it an attractive target for therapeutic intervention. We performed a randomized phase II study in vascular endothelial growth factor (VEGF) therapy refractory patients to determine whether MK-2206, an allosteric inhibitor of AKT, was more efficacious than the mammalian target of rapamycin inhibitor everolimus. Patients and methods: A total of 43 patients were randomized in a 2:1 distribution, with 29 patients assigned to the MK-2206 arm and 14 to the everolimus arm. Progression-free survival (PFS) was the primary endpoint. Results: The trial was closed at the first futility analysis with an observed PFS of 3.68 months in the MK-2206 arm and 5.98 months in the everolimus arm. Dichotomous response rate profiles were seen in the MK-2206 arm with one complete response and three partial responses in the MK-2206 arm versus none in the everolimus arm. On the other hand, progressive disease was best response in 44.8% of MK2206 versus 14.3% of everolimus-treated patients. MK-2206 induced significantly more rash and pruritis than everolimus, and dose reduction occurred in 37.9% of MK-2206 versus 21.4% of everolimus-treated patients. Genomic analysis revealed that 57.1% of the patients in the PD group had either deleterious TP53 mutations or ATM mutations or deletions. In contrast, none of the patients in the non-PD group had TP53 or ATM defects. No predictive marker for response was observed in this small dataset. Conclusions: Dichotomous outcomes are observed when VEGF therapy refractory patients are treated with MK-2206, and MK-2206 does not demonstrate superiority to everolimus. Additionally, mutations in DNA repair genes are associated with early disease progression, indicating that dysregulation of DNA repair is associated with a more aggressive tumor phenotype in RCC.

Nosocomial transmission of Cupriavidus pauculus during extracorporeal membrane oxygenation.

Patients undergoing extracorporeal membrane oxygenation (ECMO) are at increased risk of infection. We present the first known report of nosocomial infection with Cupriavidus pauculus attributable to contamination from ECMO equipment and describe the measures taken to halt subsequent infections. A cluster of infections in ECMO patients should prompt team members to consider contamination of equipment with environmental pathogens as a possible cause.

Human papillomavirus infection: the role of vaccination in pediatric patients.

Human papillomavirus (HPV) infection is the most common sexually transmitted infection among adolescents and adults in the United States. Given the prevalence of this infection and its relationship with the development of cervical cancer, HPV vaccine development has been a major public health initiative in the last decade. Despite extensive research in the development of these vaccines, there remain many unanswered questions in academic and public arenas regarding their administration and role in adolescent medicine.

Invasive pneumococcal infections in pediatric cardiac transplant patients.

BACKGROUND: Bacterial infections cause significant morbidity and mortality in cardiac transplant patients. Because Streptococcus pneumoniae is the most prominent bacterial pathogen of childhood, the objective of this study was to define the role of S. pneumoniae as a pathogen in the cardiac transplant population. METHODS: Medical records of cardiac transplant patients from March, 1990, through November, 2000, were reviewed to identify invasive pneumococcal infections after transplantation. Demographic, clinical and microbiologic data were reviewed. RESULTS: Nine (11%) of 80 patients had 12 episodes of pneumococcal bacteremia for an incidence rate of 39 cases/1,000 patient years. Patients who were African-American, transplanted before 2 years of age and transplanted because of idiopathic dilated cardiomyopathy were at increased risk of invasive pneumococcal disease (P < 0.05). Six patients were eligible for the 23-valent pneumococcal polysaccharide vaccine before their first invasive infection, but only 1 had received it at the recommended age. Most isolates (82%) were penicillin-susceptible, and no single serotype predominated. There were 2 deaths in the study group, but each was unrelated to infection. Three patients (33%) had recurrent invasive disease with a second serotype an average of 12 months after the first infection. CONCLUSIONS: The incidence of pneumococcal bacteremia in cardiac transplant patients is higher than in the general pediatric population. Risks for infection were being African-American, being younger than 2 years at the time of transplant and being transplanted because of idiopathic cardiomyopathy. It is plausible that pneumococcal vaccine would decrease this risk.

Timing of amino acid-carbohydrate ingestion alters anabolic response of muscle to resistance exercise.

The present study was designed to determine whether consumption of an oral essential amino acid-carbohydrate supplement (EAC) before exercise results in a greater anabolic response than supplementation after resistance exercise. Six healthy human subjects participated in two trials in random order, PRE (EAC consumed immediately before exercise), and POST (EAC consumed immediately after exercise). A primed, continuous infusion of L-[ring-(2)H(5)]phenylalanine, femoral arteriovenous catheterization, and muscle biopsies from the vastus lateralis were used to determine phenylalanine concentrations, enrichments, and net uptake across the leg. Blood and muscle phenylalanine concentrations were increased by approximately 130% after drink consumption in both trials. Amino acid delivery to the leg was increased during exercise and remained elevated for the 2 h after exercise in both trials. Delivery of amino acids (amino acid concentration times blood flow) was significantly greater in PRE than in POST during the exercise bout and in the 1st h after exercise (P < 0.05). Total net phenylalanine uptake across the leg was greater (P = 0.0002) during PRE (209 +/- 42 mg) than during POST (81 +/- 19). Phenylalanine disappearance rate, an indicator of muscle protein synthesis from blood amino acids, increased after EAC consumption in both trials. These results indicate that the response of net muscle protein synthesis to consumption of an EAC solution immediately before resistance exercise is greater than that when the solution is consumed after exercise, primarily because of an increase in muscle protein synthesis as a result of increased delivery of amino acids to the leg.

Molecular mechanisms contributing to necrotizing enterocolitis.

OBJECTIVE: To examine the cellular mechanisms involved in the pathogenesis of necrotizing enterocolitis (NEC). SUMMARY BACKGROUND DATA: Necrotizing enterocolitis is a major cause of death and complications in neonates; the cellular mechanisms responsible for NEC are unknown. The inducible form of cyclooxygenase (i.e., COX-2) is activated by the transcription factor nuclear factor (NF)-kappaB and is thought to play a role in inflammation. METHODS: Segments of perforated and adjacent uninvolved small intestine from neonates with NEC were analyzed for COX-2 expression by immunohistochemistry. NEC was induced in weanling (18 days old) rats by occlusion of superior mesenteric vessels for 1 hour and intraluminal injection of platelet activating factor (50 micro/kg). Small intestine was harvested for protein extraction. Western immunoblot was performed to determine expression of COX-2. Gel shift assays were performed to assess NF-kappaB binding activity. RESULTS: Immunohistochemical analysis showed increased COX-2 protein expression in the perforated intestinal sections of all 36 neonates but not in adjacent normal intestine. Increased expression of COX-2 protein and NF-kappaB binding activity was noted in the small intestine of weanling rats at 0 and 3 hours after induction of NEC. CONCLUSIONS: Increased COX-2 expression was identified in all neonatal intestinal segments resected for perforated NEC. In addition, a coordinate induction of COX-2 expression and NF-kappaB binding was noted in a rodent model of NEC. These findings suggest that the COX-2/NF-kappaB pathway may play a role in the pathogenesis of NEC. Therapeutic agents that target this pathway may prove useful in the treatment or possible prevention of NEC.

The ImmC region of phage P1 codes for a gene whose product promotes lytic growth.

The ImmC region of the temperate bacteriophage P1 contains c1, a gene that codes for a repressor of lytic growth. Located in the region upstream of c1 are four open reading frames capable of coding for low-molecular-weight proteins. The efficiency of lysogeny by P1+Cm was found to be reduced by almost 10(5)-fold when the host cells carry this region of ImmC on a multicopy plasmid. The sequences responsible for interfering with lysogen formation were localized to one of the small open reading frames (orf4) within ImmC. Insertions and deletions within orf4 suppress the virulent phenotype of P1virC mutants when introduced into the phage by recombination. These virC-suppressed mutant phage were found to be incapable of lytic growth unless the product of orf4 is provided in trans. The presence of orf4 was observed to interfere with repression by the c1 protein of ImmC-encoded promoters fused to lacZ. For this reason, we suggest that orf4 corresponds to coi, a gene previously proposed to code for an inactivator of c1-mediated repression.

The c1 genes of P1 and P7.

The c1 genes of the heteroimmune phages P1 and P7 were sequenced and their products were compared. P7c1 expression was correlated with the translation in vitro of a protein whose predicted molecular weight (33,000 daltons) is indistinguishable from that of the P1c1 repressor. The c1 regions from both P1 and P7 were found to contain open reading frames capable of coding for a 283-amino acid protein whose predicted secondary structure lacks the helix-turn-helix motif commonly associated with repressor proteins. Two P1c1 amber mutations were localized to the 283-amino acid open reading frame. The P1c1 and P7c1 sequences were found to differ at only 18 positions, all but two of which alter the third position of the affected codon and do not alter the amino acid sequence of the protein. Plasmids expressing the c1 gene from either phage cause the repression of transcription from a cloned promoter situated upstream of P1c1.

Interaction of the P1c1 repressor with P1 DNA: localization of repressor binding sites near the c1 gene.

The c1 repressor of phage P1 was previously shown (B.R. Baumstark and J.R. Scott, 1980, J. Mol. Biol. 140, 471-480) to bind specifically to P1BamHI-9, a 1.4-kb fragment that is closely linked to the c1 structural gene and spans the ends of the P1 genetic map. The position of the repressor binding site(s) relative to the ends of the genetic map and the c1 gene was investigated by testing cloned fragments of EcoRI-7 and BamHI-9 for c1 expression and repressor binding. Although sequences in both BamHI-9 and the adjacent 2.7-kb EcoRI/BamHI fragment were found to be required for the production of the c1 protein, c1 expression could be restored to the 2.7-kb fragment by the addition of a heterologous promoter (ptac). These observations are consistent with the localization of the c1 reading frame to the 2.7-kb fragment and at least part of the c1 promoter region to BamHI-9. The c1 repressor was shown to bind in vitro to two distinct cloned fragments of BamHI-9 derived from the far right side of the P1 map, indicating the presence of at least two recognition sites in this region. DNA sequence analysis revealed that these two fragments share a 23-bp region of homology. A synthetic DNA containing an 11-bp sequence from this region acts as an effective competitor for repressor binding in vitro, suggesting that at least part of the sequence shared by the fragments is involved in repressor-DNA recognition.