Gene dosage and down's syndrome: Metabolic and enzymatic changes in PC12 cells overexpressing transfected human liver-type phosphofructokinase

Down's syndrome (DS) is a human genetic disease caused by triplication of the distal third of chromosome 21 and overexpression of an unknown number of genes residing in it. The gene for the liver-type subunit of phosphofructokinase (PFKL), a key glycolytic enzyme, maps to this region and the product is overproduced in DS erythrocytes and fibroblasts. These facts, together with abnormalities which occur in DS glycolysis, make PFKL overexpression a candidate for causing some aspects of the DS phenotype. A cellular model for examining the consequences of PFKL overexpression in DS was constructed by transfecting rat PC12 cells with the human PFKL cDNA. Phosphofructokinase (PFK) isolated from PFKL-overexpressing clones was more inhibited by ATP and citrate and less activated by fructose-6-phosphate than control PFK; similar results were obtained when PFK preparations from DS and control fibroblasts were compared. In vivo NMR measurements determined that cells overexpressing PFKL performed glycolysis 40% faster than controls. These results show that overexpression of PFKL is the cause for altered biochemical regulatory characteristics of PFK in DS fibroblasts and can result in enhancement of glycolysis rates. It is also shown that increased gene dosage can exert its influence not merely by enhancing the amounts of gene products but also by altering their biochemical nature.     

Transcriptional profiling of target of RNAIII-activating protein, a master regulator of staphylococcal virulence

Staphylococcus aureus is a gram-positive bacterium that is part of the normal healthy flora but that can become virulent and cause infections by producing biofilms and toxins. The production of virulence factors is regulated by cell-cell communication (quorum sensing) through the histidine phosphorylation of target of RNAIII-activating protein (TRAP), which is a 21-kDa protein that is highly conserved among staphylococci. Using microarray analysis, we show here that the expression and phosphorylation of TRAP upregulate the expression of most, if not all, toxins known to date, as well as their global regulator agr. In addition, we show here that the expression and phosphorylation of TRAP are also necessary for the expression of genes known to be necessary for the survival of the bacteria in a biofilm, like arc, pyr, and ure. TRAP is thus demonstrated to be a master regulator of staphylococcal pathogenesis.     

Prevalence of gastroparesis before and after lung transplantation and its association with lung allograft outcomes

The main cause of late morbidity and mortality after lung transplantation is bronchiolitis obliterans syndrome (BOS). This study assesses the prevalence of gastroparesis among lung-transplant recipients and its association with BOS. The files of 139 patients who underwent nuclear gastric emptying studies before and/or three and 12 months after lung transplantation were reviewed, and the correlation of gastric emptying time (GET) at each time point with the occurrence of acute rejection or BOS (stage 0p or higher) was evaluated. Delayed gastric emptying (DGE; t(1/2) > 90 min) was documented in 50% of patients before transplantation - 74% at three months and 63% at 12 months. Median pre-transplant t(1/2) was 108 min in patients who acquired BOS and 77 min in BOS-free patients (p = 0.022). Among patients with pre-transplant DGE, 58% were BOS-free at 24 months post-operatively and 37% at 36 months; corresponding rates in patients with normal motility were 78% and 63% (p = 0.084). On multiple regression analysis adjusting for other measures of upper gastrointestinal dysfunction, GET before or three months after transplantation was significantly associated with BOS (OR 1.05 [95% CI 1.01-1.09] and OR 1.001 [1.001-1.005] per minute t(1/2)). Gastroparesis is common in lung-transplant recipients and associated with the development of BOS.     

Reversing the concept: correction of adolescent idiopathic scoliosis using the convex rod de-rotation maneuver

Purpose

To show the radiological results of adolescent idiopathic scoliosis (AIS) patients treated with posterior fusion using all-pedicle-screw construct with correction carried out using a convex rod reduction technique.

Methods

Between October 2004 and June 2007, 42 AIS patients were treated with posterior fusion using all-pedicle-screw construct with correction done through the convex side. Two patients were lost to follow-up and were not included in the study. Forty patients had a minimum follow-up of 2 years. Patients were evaluated for the deformity correction in coronal and sagittal planes and for spinal balance.

Results

The mean preoperative Cobb angle of the major curve and secondary minor curves was 60° and 41°, respectively. Immediate postoperative mean Cobb angle of the major curve and secondary minor curves was 17° and 13°, respectively. Postoperative 2-year average major curve loss of correction was 7 %. Postoperative 2-year average minor curve loss of correction was 5 %. Preoperative thoracic kyphosis of 28° was changed to 22° in 2-years follow-up. The loss of thoracic kyphosis was most noted in hyperkyphotic patients.

Conclusions

The correction of AIS by convex-sided pedicular screws yields a coronal correction comparable to what is described in the literature for segmental concave-sided screws.     

Symptomatic urinary tract infections following voiding cystourethrography

The objective of this study was to assess the frequency of symptomatic urinary tract infections (UTIs) following voiding cystourethrography (VCUG) while using prophylactic antibiotics. Medical records of 421 patients who underwent a VCUG during a period of 4 years were reviewed. Three hundred forty-nine had a VCUG following a febrile UTI, and 72 had the test for evaluation of hydronephrosis. All received prophylactic antibiotics and were evaluated within 7–10 days following the VCUG. One hundred seventy-two children (41%) had an abnormal VCUG. Seven of 421 children (1.7%) had symptoms suggestive of UTI. Two had culture negative pyuria; one had Escherichia Coli UTI, and four had Pseudomonas aeruginosa UTI. On multivariate logistic regression analysis, the risk factors contributing to the development of UTI following VCUG were the presence of vesicoureteral reflux (VUR) and its severity (odds ratio [OR] 2.52; 95% confidence interval [CI] 2.24, 2.83, p =0.001; and OR 2.32; 95% CI 2.05,2.62, p =0.04, respectively). The incidence of VCUG-induced UTI in children receiving prophylactic antibiotic therapy is low. There is a relatively high rate of Pseudomonas UTI, especially in children with moderate to severe reflux. We recommend that children with symptoms suggesting a UTI following a VCUG should be treated for Pseudomonas aeruginosa pending culture results.     

The effect of growth hormone on the development of diabetic kidney disease in rats.

BACKGROUND: Nephropathy is the most severe complication of diabetes mellitus. We investigated the effect of exogenous growth hormone (GH) administration on renal function and matrix deposition in the streptozotocin (STZ) model of type I-diabetic rat. METHODS: Adult female STZ-diabetic rats (D), non-diabetic control rats injected with saline (C) and control and diabetic rats injected with bovine GH for 3 months (CGH and DGH, respectively) were used. RESULTS: The usual renal hypertrophy seen in D animals was more pronounced in the DGH group. Creatinine clearance increased only in the D rats, but not in the other groups, including DGH. Albuminuria was observed in the D animals but was significantly elevated in the DGH group. Glomeruli from DGH animals showed more extensive matrix accumulation (manifested as an increase in mesangial/glomerular area ratio). Renal extractable insulin-like growth factor (IGF-I) mRNA was decreased in the D and DGH groups, but renal IGF-I protein was not significantly increased. Renal IGF binding protein-1 was increased in the D groups and further increased in the DGH group, at both the mRNA and protein levels. CONCLUSIONS: GH-treated diabetic rats had less hyperfiltration and more albuminuria, concomitant with more glomerular matrix deposition, when compared with regular diabetic animals. This was associated with a significant increase in renal IGFBP-1, and dissociated from IGF-I changes. Thus, in this model, GH exacerbates the course of diabetic kidney disease.     

Reduction of scar formation in full-thickness wounds with topical celecoxib treatment

Adult wound repair occurs with an initial inflammatory response, reepithelialization, and the formation of a permanent scar. Although the inflammatory phase is often considered a necessity for successful adult wound healing, fetal healing studies have shown the ability to regenerate skin and to heal wounds in a scarless manner in the absence of inflammation. The cyclooxygenase-2 (COX-2) enzyme, a known mediator of inflammation, has been shown to contribute to a variety of inflammatory conditions and to the development of cancer in many organs. To examine the role of COX-2 in the wound healing process, incisional wounds were treated topically with the anti-inflammatory COX-2 inhibitor celecoxib. Acutely, celecoxib inhibited several parameters of inflammation in the wound site. This decrease in the early inflammatory phase of wound healing had a significant effect on later events in the wound healing process, namely a reduction in scar tissue formation, without disrupting reepithelialization or decreasing tensile strength. Our data suggest that in the absence of infection, adult wound healing is able to commence with decreased inflammation and that anti-inflammatory drugs may be used to improve the outcome of the repair process in the skin by limiting scar formation.