The effect of griseofulvin on the heme pathway. Studies on tissue explant cultures

The effect of griseofulvin on porphyrin biosynthesis was studied in vitro and in vivo using liver and skin explants from mice. Neither porphyrin nor precursors accumulation was detected after in vitro treatment of explants with griseofulvin. Culture medium porphyrins formed from added delta-amino-laevulinic acid (ALA) were increased after oral chronic intoxication. Similar results were obtained by cutaneous and oral intoxication. Consequently griseofulvin topical application is proposed as an alternative method to produce experimental erythropoietic protoporphyria. Probable intoxication mechanisms are proposed to explain the porphyrinogenic action of griseofulvin.     

On the contribution of deoxy-hemoglobin to MRI gray–white matter phase contrast at high field

High field (≥ 7 T) MRI studies based on signal phase have been used to improve visualization of the fine structure of the brain, most notably the major white matter fiber bundles, the gray–white matter subdivision, and the laminar cortical architecture. The observed contrast has been attributed in part to local variations in magnetic susceptibility arising from iron in storage proteins and tissue lipid. Another contribution could come from the paramagnetic blood constituent deoxy-hemoglobin, the tissue concentration of which may vary through local variations in vascular density. To investigate this possibility, we examined phase contrast between gray and white matter in rats after intravenous administration of a superparamagnetic contrast agent at various dosages. At the maximum dosage (3 mg Fe/kg), which resulted in an estimated paramagnetic susceptibility shift 4–8 times larger than deoxy-hemoglobin, we observed a negligible increase in phase contrast between gray and white matter. This result suggests that endogenous deoxy-hemoglobin has no significant contribution to phase contrast between gray and white matter.     

Heterogeneity of Pseudomonas aeruginosa in Brazilian Cystic Fibrosis Patients

The aim of this study was to assess the diversity and genomic variability of Pseudomonas aeruginosa isolates from cystic fibrosis (CF) patients being treated at a university hospital in Brazil. Ninety-seven isolates of P. aeruginosa from 43 CF patients were characterized by macrorestriction analysis of chromosomal DNA by pulsed-field gel electrophoresis (PFGE) and tested for susceptibility to 20 antimicrobial agents by broth microdilution. It was possible to evaluate single isolates from 20 patients and multiple isolates (two to seven) from 23 patients collected during a 22-month period. Among all of the unrelated patients, we detected only one pair of patients sharing a common strain. Among the 77 isolates from 23 patients who had multiple isolates analyzed, we identified 37 major types by PFGE, and five different colonization patterns were recognized. The isolates were susceptible to several antimicrobial agents, although consecutive isolates from the same patient may display differences in their susceptibilities. Mucoid isolates were more resistant (P < 0.001) than nonmucoid isolates to five antibiotics. Our results indicate that CF patients remain colonized by more than one strain of P. aeruginosa for long periods of time. In addition, the finding of several different genotypes in the same patient suggests that the colonizing strain may occasionally be replaced.     

Benefits of pentoxifylline for skin flap tissue repair in rats

PurposeTo assess the action of pentoxifylline, administered by subcutaneous route, on skin flap tissue repair in rats, and to verify the histological aspects and biomarkers.MethodsThirty-two male Wistar rats were divided into four groups: control (CT) and treated with pentoxifylline (P1, P3 and P5). Modified McFarlane technique flap was used. Ten days later, the animals were euthanized and the areas of viable and necrotic tissue were evaluated. Hematoxylin/eosin staining was used to assess the morphometric characteristics of the number of vessels and epithelial thickness. Picrosirius red was used to assess collagen density. VEGF and TGF-?1 levels on the skin flap and serum of the animals were measured by the ELISA method.ResultsThe macroscopic evaluation of the skin flap dimensions showed reduced necrotic tissue in the pentoxifylline (p < 0.05) treated groups. There was an increase in angiogenesis and reepithelization, demonstrated by analyses with an increased number of vessels (p < 0.05), VEGF and epithelial thickness. Fibrogenic effect showed decreased collagen density and TGF-β1 in the skin flap and serum.ConclusionThe benefits of pentoxifylline administered by subcutaneous route, at dose 100 mg/kg, which was effective to improve the survival of skin flap by acting on tissue repair components, stimulating angiogenesis and reepithelization, in addition to reducing fibrogenesisKey words: Pentoxifylline, Surgical Flaps, Wound Healing, Survival, Rats     

The implications of following dietary advice regarding fish consumption frequency and meal size for the benefit (EPA + DHA and Se) versus risk (MeHg) assessment

Fish contain healthy nutrients, such as ω3 polyunsaturated fatty acids, particularly eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), which protect against cardiovascular disease, and selenium (Se), which reduces methylmercury (MeHg) toxicity. Fish are also a dietary source of MeHg. This requires an assessment of the benefits versus risks. A risk-benefit evaluation showed that blue shark regardless of the way it is cooked generated high probabilities of surpassing the MeHg tolerable weekly intake (TWI), >22%. In tuna, boiling and grilling led to higher MeHg risks than canning, 6–37% versus <7%. EPA?+?DHA contributed for the prevention of coronary disease. With exception of blue shark, Se neutralised MeHg toxicity. Higher MeHg risk was associated with blue shark and boiled and grilled tuna consumption. For tuna, however, high Se content after boiling and grilling may mitigate MeHg risk.     

Estimation of skeletal muscle mass in patients with spinocerebellar ataxia type 3 and 10

Background: Neurodegenerative diseases may progress to a level in which patients present spontaneous weight loss, resulting in increased falls and functional disabilities when the disease is associated with muscle mass depletion.

Objective: Evaluate the muscle compartment in patients presenting spinocerebellar ataxia (SCA) type 3 and 10.

Methods: Forty-six patients presenting SCA type 3 and 10 were assessed and 76 volunteers were selected to the control group. In order to evaluate the muscle compartment, muscle mass anthropometric measurements were assessed and total skeletal muscle mass calculated through a predictive equation.

Results: Women with SCA3 presented greater weight loss and muscle mass reduction compared to those with SCA10 and the control group. Among the predictive measurements, calf muscle circumference showed a more significant correlation with total skeletal muscle mass (p = 0.718).

Conclusion: Patients presenting both types of ataxia did not show severe depletion in their nutritional status; however, those with SCA3 displayed greater weight loss and muscle mass reduction compared to the SCA10 group.