Bacterial Anaerobic Synthesis Gas (Syngas) and CO2+H2 Fermentation.

Anaerobic bacterial gas fermentation gains broad interest in various scientific, social, and industrial fields. This microbial process is carried out by a specific group of bacterial strains called acetogens. All these strains employ the Wood-Ljungdahl pathway but they belong to different taxonomic groups. Here we provide an overview of the metabolism of acetogens and naturally occurring products. Characteristics of 61 strains were summarized and selected acetogens described in detail. Acetobacterium woodii, Clostridium ljungdahlii, and Moorella thermoacetica serve as model organisms. Results of approaches such as genome-scale modeling, proteomics, and transcriptomics are discussed. Metabolic engineering of acetogens can be used to expand the product portfolio to platform chemicals and to study different aspects of cell physiology. Moreover, the fermentation of gases requires specific reactor configurations and the development of the respective technology, which can be used for an industrial application. Even though the overall process will have a positive effect on climate, since waste and greenhouse gases could be converted into commodity chemicals, some legislative barriers exist, which hamper successful exploitation of this technology.

Estimating the glomerular filtration rate in the general population using different equations: effects on classification and association.

BACKGROUND/AIMS: Several formulas for glomerular filtration rate (GFR) estimation, based on serum creatinine or cystatin C, have been proposed. We assessed the impact of some of these equations on estimated GFR (eGFR) and chronic kidney disease (CKD) prevalence, and on the association with cardiovascular risk factors, in a general population sample characterized by a young mean age. METHODS: We studied 1,199 individuals from three Alpine villages enrolled into the MICROS study. eGFR was obtained with the 4- and 6-parameter MDRD study equations, the Virga equation, and with the three CKD-EPI formulas for creatinine, cystatin C, and the combination of creatinine and cystatin C. We assessed the concordance between quantitative eGFR levels, CKD prevalence, and in terms of association with total, LDL, and HDL cholesterol. RESULTS: The highest and lowest eGFR levels corresponded to the cystatin C-based and MDRD-4 equations, respectively. CKD prevalence varied from 1.8% (Virga) to 5.8% (MDRD-4). The CKD-EPI based on creatinine showed the highest agreement with all other equations. Agreement between methods was higher at lower eGFR levels, older age, and in the presence of diabetes and hypertension. Creatinine-based estimates of eGFR were associated with total and low-density lipoprotein but not high-density lipoprotein cholesterol. The opposite was observed for the cystatin C-based GFR. CONCLUSION: GFR estimation is strongly affected by the chosen equation. Differences are more pronounced in healthy and younger individuals. To identify CKD risk factors, the choice of the equation is of secondary importance to the choice of the biomarker used in the formula. If eGFR is not calibrated to a gold standard GFR in the general population, reports about CKD prevalence should be considered with caution.

Adult patients with sporadic polycystic kidney disease: the importance of screening for mutations in the PKD1 and PKD2 genes.

BACKGROUND: ADPKD is one of the most common inherited disorders, with high risk for end-stage renal disease. Numerous patients, however, have no relatives in whom this disorder is known and are unsure whether they may transmit the disease to their offsprings. The aim of this study was to evaluate whether germline mutation analysis adds substantial information to clinical symptoms for diagnosis of ADPKD in these patients. METHODS: Clinical data included renal function and presence of liver or pancreas cysts, heart valve insufficiency, intracranial aneurysms, colonic diverticles, and abdominal hernias. Family history was evaluated regarding ADPKD. Germline mutation screening of the PKD1 and PKD2 genes was performed for intragenic mutations and for large deletions. RESULTS: A total of 324 adult patients with ADPKD including 30 patients without a family history of ADPKD (sporadic cases) were included. PKD1 mutations were found in 24/30 and PKD2 mutations in 6 patients. Liver cysts were present in 14 patients and intracranial aneurysms in 2 patients. Fourteen patients (45%) had no extrarenal involvement. Compared to the 294 patients with familial ADPKD, the clinical characteristics and the age at the start of dialysis were similar in those with sporadic ADPKD. CONCLUSION: The clinical characteristics of patients with sporadic and familial ADPKD are similar, but sporadic ADPKD is often overlooked because of the absence of a family history. Molecular genetic screening for germline mutations in both PKD1 and PKD2 genes is essential for the definitive diagnosis of ADPKD.

Fenestration of the Gerota's fascia as symptomatic treatment of floating kidneys.

A 16-year-old man presented with severe nephrotic syndrome complicated by massive perirenal fluid. Percutaneous drainage of fluid was performed 3 times, followed by improvement in renal function and hypertension, but perirenal fluid recurred within days. Nephrotic syndrome was unresponsive to steroid therapy. A laparoscopic bilateral fenestration of Gerota's fascia and peritoneum allowed permanent drainage of fluid into the peritoneal cavity. During the same procedure, a renal wedge biopsy was performed. Histological examination showed advanced focal glomerular sclerosis of the tip lesion variant. The glomerular disease was refractory to further treatment with cyclophosphamide, mycophenolate, and rituximab. However, perirenal fluid did not recur despite persistent nephrotic syndrome, showing that fenestration of Gerota's fascia is a successful treatment of floating kidneys in such patients.