Markers of oxidative stress in adipose tissue during Trypanosoma cruzi infection

The protozoan parasite Trypanosoma cruzi causes Chagas disease. Cardiac and adipose tissues are among the early targets of infection and are sites of persistent infection. In the heart and adipose tissue, T. cruzi infection results in an upregulation of pro-inflammatory mediators. In the heart, infection is associated with an increase in the markers of oxidative stress. To date, markers of oxidative stress have not been evaluated in adipose tissue in this infection. Brown and white adipose tissues were obtained from CD-1 mice infected with the Brazil strain of T. cruzi for 15, 30, and 130 days post infection. Protein carbonylation and lipid peroxidation assays were performed on these samples. There was an upregulation of these markers of oxidative stress at all time-points in both white and brown adipose tissue. Determinants of anti-oxidative stress were downregulated at similar time-points. This increase in oxidative stress during T. cruzi infection most likely has a deleterious effect on host metabolism and on the heart.     

Determination of Mechanical Properties of Spatially Heterogeneous Breast Tissue Specimens Using Contact Mode Atomic Force Microscopy (AFM)

This paper outlines a comprehensive parametric approach for quantifying mechanical properties of spatially heterogeneous thin biological specimens such as human breast tissue using contact-mode Atomic Force Microscopy. Using inverse finite element (FE) analysis of spherical nanoindentation, the force response from hyperelastic material models is compared with the predicted force response from existing analytical contact models, and a sensitivity study is carried out to assess uniqueness of the inverse FE solution. Furthermore, an automation strategy is proposed to analyze AFM force curves with varying levels of material nonlinearity with minimal user intervention. Implementation of our approach on an elastic map acquired from raster AFM indentation of breast tissue specimens indicates that a judicious combination of analytical and numerical techniques allow more accurate interpretation of AFM indentation data compared to relying on purely analytical contact models, while keeping the computational cost associated an inverse FE solution with reasonable limits. The results reported in this study have several implications in performing unsupervised data analysis on AFM indentation measurements on a wide variety of heterogeneous biomaterials.     

Methanobrevibacter smithii Is the Predominant Methanogen in Patients with Constipation-Predominant IBS and Methane on Breath

Purpose

Among irritable bowel syndrome (IBS) patients, breath methane producers overwhelmingly have constipation predominance (C-IBS). Although the most common methanogen in humans is Methanobrevibacter smithii, incidence and type of methanogenic bacteria in C-IBS patients are unknown.

Methods

By use of a questionnaire and lactulose breath testing, subjects with Rome II C-IBS and methane (>3?ppm) were selected (n?=?9). The control group included subjects with IBS who had no breath methane (n?=?10). Presence of bacterial DNA was assessed in a stool sample of each subject by quantitative-PCR using universal 16S rDNA primer. M. smithii was quantified by use of a specific rpoB gene primer.

Results

M. smithii was detected in both methane and non-methane subjects. However, counts and relative proportion of M. smithii were significantly higher for methane-positive than for methane-negative subjects (1.8?×?10⁷?±?3.0?×?10⁷ vs 3.2?×?10⁵?±?7.6?×?10⁵?copies/g wet stool, P?<?0.001; and 7.1?±?6.3?% vs 0.24?±?0.47?%, P?=?0.02 respectively). The minimum threshold of M. smithii resulting in positive lactulose breath testing for methane was 4.2?×?10⁵?copies/g wet stool or 1.2?% of total stool bacteria. Finally, area-under-curve for breath methane correlated significantly with both absolute quantity and percentage of M. smithii in stool (R?=?0.76; P?<?0.001 and R?=?0.77; P?<?0.001 respectively).

Conclusions

M. smithii is the predominant methanogen in C-IBS patients with methane on breath testing. The number and proportion of M. smithii in stool correlate well with amount of breath methane.     

Phenazopyridine associated acute interstitial nephritis and review of literature

Phenazopyridine is a urinary analgesic; commonly seen side-effects of this drug include, orange discoloration of urine, methemoglobinemia, yellowish skin discoloration, hepatitis and acute renal failure. Various case reports with phenazopyridine associated acute renal failure secondary to acute tubular necrosis have been reported in the literature. Acute kidney injury in these patients is caused by either direct injury to renal tubular epithelial cells or secondary to pigment induced nephropathy from hemolytic anemia. Hypoxic injury from phenazopyridine-induced methemoglobinemia has been well documented. We report a case of biopsy proven acute interstitial nephritis, associated with therapeutic doses of phenazopyridine without any evidence of methemoglobinemia or other mechanism of renal injury. Clinicians should be aware of the toxicity of this commonly used drug and should look closely for signs of renal insufficiency. Identifying and stopping the offending medication stays as the first step, but recent studies indicate that early steroid administration improves renal recovery, as well as decreasing the risk of progression to chronic kidney disease with fibrosis and consequent permanent renal damage.     

Cell phones and male infertility: dissecting the relationship

There has been a tremendous increase in the use of mobile phones in the past decade and concerns are growing about the possible hazardous effects of radio-frequency electromagnetic waves (EMW) emitted by these devices on human health. Preliminary studies, though with limitations in study design, suggest a possible link between cell phone use and infertility. A recent study found that use of cell phones adversely affects the quality of semen by decreasing the sperm counts, motility, viability and morphology. Evidence of detrimental effect of mobile phones on male fertility is still equivocal as studies have revealed a wide spectrum of possible effects ranging from insignificant effects to variable degrees of testicular damage. Although previous studies suggested a role of cell phone use in male infertility, the mode of action of EMW emitted from cell phones on the male reproductive system is still unclear. EMW can affect the reproductive system via an EMW-specific effect, thermal molecular effect or combination of both. Studies performed on human males are scarce and therefore further studies with a careful design are needed to determine the effect of cell phone use on male-fertilizing potential.