Publications

BACKGROUND/AIMS

Obesity frequently leads to changes in fatty acid metabolism with subsequent fatty infiltration in the liver.

METHODS

In this study, metabolic profile of the livers and blood from lean and obese Zucker rats was established based on quantitative nuclear magnetic resonance spectroscopy (NMR) analysis.

RESULTS

(1)H NMR on liver lipid extracts indicated significantly increased concentrations of total fatty acids and triglycerides. (31)P NMR on liver extracts revealed that obese livers have a compromised energy balance (low [ATP/ADP]) with decreased mitochondrial activity. Simultaneously, increased glycolytic activity was detected. The most pronounced differences were highly increased methionine and decreased betaine concentrations in obese animals. This suggests a significant alteration in methionine metabolism, which may be in part responsible for the development of steatosis, induction of mitochondrial dysfunction, and increased vulnerability of fatty livers to ischemia/reperfusion injury. A trend towards decreased hepatic glutathione concentrations as well as a reduced [PUFA/MUFA] ratio were present in the obese group, indicating increased oxidative stress and lipid peroxidation.

CONCLUSIONS

In conclusion, NMR analysis on blood and liver tissue from obese Zucker rats reveals specific metabolic abnormalities in mitochondrial function and methionine metabolism, which result in a decreased hepatic energy state.

BACKGROUND

Nasal carriage of methicillin-resistant Staphylococcus aureus (MRSA) plays a key role in the epidemiology and pathogenesis of disease. The purpose of this study was to determine the characteristics and dynamics of nasal strains of MRSA, as well as their relation to community-associated disease activity.

METHODS

This study is a cross-sectional survey and molecular epidemiologic analysis of nasal colonization by S. aureus in homeless and runaway youths, an underserved population at high risk for staphylococcal disease.

RESULTS

Of the 308 study participants, 27.6% carried S. aureus, and 6.2% carried MRSA. Subgroups of individuals with increased MRSA carriage rates were also at highest risk for community-associated MRSA infection; these subgroups included individuals with either HIV infection or AIDS, injection drug users, patients with abscesses, and those recently hospitalized. Multilocus sequence typing and pulsed-field gel electrophoresis identified 2 genotypes--ST59:P (USA1000) and ST8:S (USA300)--that accounted for 84.2% (16/19) of the MRSA isolates carried. The genotypes were distinct from nosocomial genotypes endemic in the hospital, although they originated from individuals with prior exposure to health care.

CONCLUSIONS

Comparison of MRSA strains from asymptomatic carriers versus concurrently collected community-associated clinical strains from patients treated at local health-care facilities allowed for the identification of 3 population dynamics of nasal strains of MRSA: (1) endemic clones--for example, ST8:C and ST59:P--sustained asymptomatic carriage and infection over prolonged periods; (2) an epidemic clone, ST8:S, demonstrated enhanced capacity for rapid transmission and widespread infections; and (3) an outbreak clone, ST30:Z (USA1100), was highly infectious but exhibited poor asymptomatic transmission.

Although many cross-sectional studies and a small number of randomized controlled trials have addressed the relationship between schistosomiasis and anemia, the conflicting results make the magnitude of the relationship unclear. In fact, only one randomized controlled trial that treated solely for schistosomiasis has demonstrated an impact of praziquantel on hemoglobin concentration. The potential mechanisms underlying a relationship between schistosomiasis and anemia are also unclear. In this article, we discuss four possible mechanisms that might mediate this relationship, based on animal and human models, including extra-corporeal loss of iron, splenomegaly leading to red blood cell sequestration, autoimmune hemolysis and anemia of inflammation.

Recently, 131Cs seeds have been introduced for prostate permanent seed implants. This type of seed has a relatively short half-life of 9.7 days and has its most prominent emitted photon energy peaks in the 29-34 keV region. Traditionally, 145 and 125 Gy have been prescribed for 125I and 103Pd seed prostate implants, respectively. Since both the half-life and dosimetry characteristics of 131Cs seed are quite different from those of 125I and 103Pd, the appropriate prescription dose for 131Cs seed prostate implant may well be different. This study was designed to use a linear quadratic radiobiological model to determine an appropriate dose prescription scheme for permanent 131Cs seed prostate implants. In this model, prostate edema was taken into consideration. Calculations were also performed for tumors of different doubling times and for other related radiobiological parameters of different values. As expected, the derived prescription dose values were dependent on type of tumors and types of edema. However, for prostate cancers in which tumor cells are relatively slow growing and are reported to have a mean potential doubling time of around 40 days, the appropriate prescription dose for permanent 131Cs seed prostate implants was determined to be: 127(+5)(-12)Gy if the experiences of 125I seed implants were followed and 121(+0)(-3)Gy if the experiences of 103Pd followed.

We performed a cohort study of 392 postmenopausal women who had coronary disease to assess whether baseline serum endothelin-1 level predicts angiographic disease progression, nonfatal myocardial infarction, or death. Angiographic progression was defined as the annualized change in minimal lumen diameter of all qualifying lesions for each patient. Twenty-nine patients died or had a myocardial infarction during follow-up. Each picogram per milliliter increase in endothelin-1 was associated with a 1.8-fold increased risk of death or myocardial infarction. After adjustment for potential confounders, endothelin-1 remained a predictor of clinical events but was not correlated with angiographic progression.