Growth hormone treatment of renal growth failure during infancy and early childhood

Despite major progress in dialysis, nutrition and drug treatment in the past 20 years, growth of infants and toddlers with chronic kidney disease (CKD) remains a major challenge in paediatric nephrology. Our hypothesis is that early growth deficit is one of the most important factors for impaired final height in children with CKD, and we conclude that early implementation of recombinant human growth hormone (rhGH) therapy should be offered to infants with growth failure. Infants with delayed growth, adequate caloric intake and stable parameters of bone metabolism are candidates for rhGH therapy. One predictive factor for the selection of infants for rhGH treatment may be growth retardation at birth. Our conclusion from the limited published data is that the use of rhGH in young children with CKD is effective and safe. Compared with its use in older children, the early use of growth hormone requires lower absolute dosages of rhGH, which therefore reduce the annual treatment costs and allow earlier renal transplantation. Furthermore, an early start on rhGH improves the psychosocial situation later in childhood and may lead to a further improvement in adult height. A multi-centre randomised controlled study should be initiated to analyse the short-term and long-term effects of early rhGH therapy on infants with CKD. Remark from the EditorsThe article by Mencarelli et al. was published in the May 2009 issue of the Journal and can be found at doi:.     

Effects of Acute Nitric Oxide Synthase Inhibition on Lower Leg Vascular Function in Chronic Tetraplegia

Background/Objective:

To improve our understanding of the lower-leg vascular responses of nitric oxide synthase inhibition in persons with tetraplegia.

Participants:

Six people with chronic tetraplegia and 6 age-matched controls.

Methods:

Lower-leg relative vascular resistance and venous volume variation were obtained by venous occlusion plethysmography and blood pressure by auscultation at baseline. Postintravenous infusion of the nitric oxide synthase inhibitor N^G-nitro-l-arginine-methyl-ester (1 mg·kg⁻¹) or placebo on separate days.

Results:

At baseline in the group with tetraplegia compared with controls, mean arterial pressure and relative vascular resistance of the leg were significantly lower. After nitric oxide synthase inhibition, mean arterial pressure and lower leg vascular resistance were significantly elevated in both groups. There were no group or intervention differences in venous volume variation.

Conclusion:

These preliminary results suggest that nitric oxide synthase inhibition with 1 mg·kg⁻¹ N^G-nitro-l-arginine-methyl-ester normalizes seated blood pressure and lower leg vascular resistance to control group baseline levels.     

Safety of simultaneous colon and liver resection for colorectal liver metastases

BACKGROUND/AIM: Surgical strategy for the treatment of resectable synchronous hepatic metastases of colorectal cancer (CRC) remains controversial. The aim of this study was to assess safety of simultaneous colon and liver rese cions and the direct effects of this type of treatment upon morbidity and mortality of the patients with synchronus hepatic metastases of CRC. METHODS: Intraoperative and postoperative data of 31 patients with simultaneous liver and colorectal resection were compared with the data of 51 patients who had undergone colon and hepatic resection in the staging setting. Analized were demographic data, number of metastases, type of the liver resection, operation time, intraoperative blood loss, percentage of postoperative complications, morbidity and mortality and lenght of hospitalisation. RESULTS: In the group of the patients operated simultaneously 5 hepatectomies, 3 sectionectomies, 2 trisegmentectomies, 3 bisegmentectomy, 6 segmentectomies, and 12 metastasectomies were combined with colon resection. In this group operation time (280 vs. 330 minutes) and in traoperative blood loss (450 vs. 820 ml) were lower than those in the two staged operation group. Postoperative complication rate was lower in the simultaneous group (19.35%o) than in the two-staged operation group (19.60%), without statistical significance. There was no hospital mortality in both groups. The patients having simultaneous resection required fewer days in the hospital (median 10.2 days) than the patients undergone operation in the two stage (18.34 days). CONCLUSION: By avoiding a second laparotomy, overall operation time, blood loss, hospital stay and complication rate are reduced with no change in hospital mortality, so simultaneous colon and hepatic resection performed by the competent surgeons are safe and efficient for the treatment of synchronous colorectal liver metastases.     

Growth impairment shows an age-dependent pattern in boys with chronic kidney disease

The impact of chronological age on longitudinal body growth from early childhood through adolescence using detailed anthropometric methods has not yet been studied in children with chronic kidney disease (CKD). We have evaluated growth failure by measuring four components of linear growth: body height (HT), sitting height (SHT), arm length (AL) and leg length (LL). Data were prospectively collected for up to 7 years on 190 boys (3–21 years old) with congenital or hereditary CKD (all had developed at least stage 2 CKD by the age of 10 years). Patients showed the most severe growth failure in early childhood, followed by an acceleration in growth in pre-puberty, a slowing-down of growth at puberty, as expected, and thereafter a late speeding-up of growth until early adulthood. This pattern was observed irrespective of the degree of CKD and different treatment modalities, such as conservative treatment, recombinant human growth hormone (rhGH) therapy or transplantation. LL showed the most dynamic growth changes of all the parameters evaluated and emerged as the best indicator of statural growth in children with CKD. A specific age-dependent pattern of physical growth was identified in pediatric male CKD patients. This growth pattern should be considered in the evaluation of individual growth and the assessment of treatment efficacy such as rhGH therapy.     

Glomerular eNOS gene expression during postnatal maturation and AT1 receptor inhibition

Glomerular maturation increases from immature superficial to advanced juxtamedullary nephrons, while nephrogenesis continues postnatally in porcine kidneys. Endothelial NOS, eNOS, shows significant postnatal renal developmental regulation, perhaps mediated by Angiotensin II (AII). The objective was to compare eNOS mRNA gene expression between superficial and juxtamedullary glomeruli obtained from piglets and adult pigs utilizing laser capture microdissection during basal conditions and, to determine the role of the AII AT1 receptor, AT1, after chronic AT1 inhibition (AT1X) with candesartan. Superficial glomerular eNOS expression was lowest in newborns (NB) and at 7 days, and was highest in 14, 21 day old piglets and adults. Juxtamedullary glomerular eNOS, while similar in NB, 14, 21 day and adult, dipped to the lowest level at 7 days. Juxtamedullary glomerular eNOS expression in the NB was 7 fold greater than in superficial glomeruli. AT1X did not change eNOS expression in adult glomeruli. AT1X significantly reduced NB eNOS expression in both superficial, 90 ± 10%, and juxtamedullary glomeruli, 89 ± 5% respectively. In conclusion, eNOS gene expression demonstrates significant differences between NB superficial and juxtamedullary glomeruli, significant postnatal developmental regulation of both glomerular locations, and this expression may be mediated in the NB by AII via the AT1 receptor.     

A radiofrequency-assisted minimal blood loss liver parenchyma dissection technique

BACKGROUND/AIMS: Intraoperative blood loss is still a major concern for surgeons operating on the liver since it is associated with a significantly higher rate of postoperative complications and shorter long-term survival. An original radiofrequency (RF)-assisted minimal blood loss technique for transecting liver parenchyma is presented. METHODS: In a prospective study, starting November 2001 and ending December 2005, a total of 90 RF-assisted liver resections were done. Pre-cut coagulative desiccation was produced by the Cool-tip (Valleylab, Tyco) water-cooled, single, RF tumor ablation electrode connected to a 480-kHz 200 W generator (Valleylab Cool-tip RF System). Vascular occlusion techniques and low central venous pressure anesthesia were not used. RESULTS: Only 14 (15.5%) patients received blood transfusion (mean transfused blood volume 397 ml; mode 310 ml) and 10 of 14 patients received <310 ml of blood. There was no statistical difference between the patients who underwent major and minor liver resection in frequency of blood transfusion. Blood loss was associated with dense adhesions and difficult liver mobilization and not with liver transection. CONCLUSION: The 'sequential coagulate-cut' RF-assisted liver resection technique is a safe liver transection technique associated with minimal blood loss and it has facilitated tissue-sparing liver resection.     

Survivin gene promoter polymorphism -31G/C as a risk factor for keratocystic odontogenic tumor development

Several single nucleotide polymorphisms in survivin gene promoters, notably -31G/C, have been shown to modulate the expression and activity of the survivin protein. Consequently, the -31G/C polymorphism has been identified as a risk factor for the development of several types of tumors. The aim of this study was to investigate a possible association between the -31G/C polymorphism and the risk for keratocystic odontogenic tumor (KCOT) development. DNA from 52 biopsy specimens of KCOTs and from 82 buccal swabs of healthy individuals was subjected to PCR restriction fragment length polymorphism analysis to identify individual genotypes. The distribution of genotypes in KCOT and control groups, respectively, was: GG: 30 (57.7%) vs. 26 (31.7%); CG: 17 (32.7%) vs. 45 (54.9%); and CC: 5 (9.6%) vs. 11 (13.4%), respectively. These differences were statistically significant. The G allele was more common in the KCOT group than in the control group: 76 (74%) vs. 96 (59%), respectively. Logistic regression analysis showed that GC heterozygotes had a considerably decreased susceptibility for KCOTs compared with GG homozygotes. The same was true for GC+CC vs. GG. The GG genotype of the -31G/C polymorphism might be a risk factor for KCOT development.     

Plant cytokinin analogues with inhibitory activity on cyclin-dependent kinases exert their antiproliferative effect through induction of apoptosis initiated by the mitochondrial pathway: determination by a multiparametric flow cytometric analysis

OBJECTIVE: Regulation of the cell cycle by cyclin-dependent kinase (CDK) activity occurs at multiple levels and is often altered in human cancers. Therefore, CDK activity has been targeted for drug discovery, and a number of small molecules have now been identified as CDK inhibitors. Plant cytokinin analogues with CDK inhibitory activity and antiproliferative effects were studied to characterize the cellular basis of the cytotoxic effect. METHODS: The IC(50) value (concentration at which 50% of the cell proliferation is inhibited) and AC(50) value (concentration at which 50% of the cell population is apoptotic) were determined by flow cytometry and microscopy, respectively. A new multiparametric flow cytometric analysis was used to study the sequence of different apoptotic events. In this assay, analysis of phosphatidylserine exposure, mitochondrial membrane depolarization, activation of caspases and DNA condensation were combined. RESULTS: Treatment of Jurkat and KG1 cells with the CDK inhibitors results in a decrease of viable cells and a parallel increase in percentage of apoptotic cells. Apoptosis was accompanied by a rapid decrease of mitochondrial membrane potential, which precedes DNA condensation, exposure of phosphatidylserine and activation of caspases. CONCLUSIONS: The main cellular mechanism of the antiproliferative effect of plant cytokinin analogues with CDK inhibitory activity is the induction of apoptosis. The multiparametric flow cytometric technique allowed to follow the kinetics of various aspects of apoptotic cell changes and demonstrated that cytokinin analogue-induced apoptosis starts through the mitochondrial pathway. This technique could also become of value for the rapid screening of pro-apoptotic properties of chemotherapeutic compounds.     

Intrapituitary adenoviral administration of 7B2 can extend life span and reverse endocrinological deficiencies in 7B2 null mice

The prohormone convertase PC2 requires the aid of a helper protein, known as 7B2, for production of active enzyme. Deletion of 7B2 results in a lethal phenotype resembling Cushing's disease. In this study, we have investigated the effect of a single low dose of recombinant adenovirus vector encoding 7B2 and delivered directly to the pituitary of 7B2 nulls on pituitary ACTH, plasma ACTH, corticosterone, alpha MSH and glucose, and survival time. We show that after injection of recombinant adenovirus encoding 27-kDa 7B2 into 7B2 nulls, transgene expression, as measured by RIA for 7B2, exhibits a transient elevation in the pituitary and blood, with a slight but significant elevation of PC2 activity in pituitaries of 7B2 nulls and a drop in the level of circulating ACTH concomitant with a small increase in circulating alpha MSH. The level of circulating blood glucose was increased, and that of corticosterone was decreased. Lastly, slight but significantly prolonged survival times were observed. These data showing partial rescue of 7B2 nulls support the idea that adenoviral administration of 7B2 will represent an effective means to study the role of this interesting neuroendocrine protein on endocrine function in vivo.     

Cadmium specific proteomic responses of a highly resistant Pseudomonas aeruginosa san ai

Pseudomonas aeruginosa san ai is a promising candidate for bioremediation of cadmium pollution, as it resists a high concentration of up to 7.2 mM of cadmium. Leaving biomass of P. aeruginosa san ai exposed to cadmium has a large biosorption potential, implying its capacity to extract heavy metal from contaminated medium. In the present study, we investigated tolerance and accumulation of cadmium on protein level by shotgun proteomics approach based on liquid chromatography and tandem mass spectrometry coupled with bioinformatics to identify proteins. Size exclusion chromatography was used for protein prefractionation to preserve native forms of metalloproteins and protein complexes. Using this approach a total of 60 proteins were observed as up-regulated in cadmium-amended culture. Almost a third of the total numbers of up-regulated were metalloproteins. Particularly interesting are denitrification proteins which are over expressed but not active, suggesting their protective role in conditions of heavy metal exposure. P. aeruginosa san ai developed a complex mechanism to adapt to cadmium, based on: extracellular biosorption, bioaccumulation, the formation of biofilm, controlled siderophore production, enhanced respiration and modified protein profile. An increased abundance of proteins involved in: cell energy metabolism, including denitrification proteins; amino acid metabolism; cell motility and posttranslational modifications, primarily based on thiol-disulfide exchange, were observed. Enhanced oxygen consumption of biomass in cadmium-amended culture versus control was found. Our results signify that P. aeruginosa san ai is naturally well equipped to overcome and survive high doses of cadmium and, as such, has a great potential for application in bioremediation of cadmium polluted sites.

When exposed to cadmium a highly resistant strain P. aeruginosa san ai responds by an increased metalloprotein expression (particularly denitrification proteins), an enhanced respiration, and a pronounced thiol-disulfide protein modifications.