Optical micro-knot resonator hydrophone.

We present results of what are believed to be the first underwater acoustic sensor using an optical micro-knot resonator. The mechanism involves straining the micro-fibre loop of the knot via an appropriate encapsulation material. The micro-knot sensor exhibited a spectral full-width half-depth of 37.7pm with a Q-factor of 41100 after deconvolution with the source. The shift in wavelength at 1550nm was observed to be around 67pm RMS when exposed to underwater acoustic excitation at 40Hz demonstrating a normalized sensitivity of -288 dB re µPa(-1), or 5.83 fm/Pa.

Iron and its sensitive balance in the cell.

Iron is vital in life because it is an important component of molecules that undergoes redox reactions or transport oxygen. However, the existence of two stable and inter-convertible forms of iron, iron(III) and iron(II), makes possible one electron being transferred to or captured from other species to form radicals. In particular, superoxide and hydroxyl radicals may be formed in these reactions, both with capacity of attacking other molecules. DNA is one important target and a vast literature exists showing that attack of hydroxyl radical to DNA leads to cell death cellular necrosis, apoptosis, mutation and malignant transformation. Therefore, a fine balance must exist at various levels of an organism to maintain iron concentration in a narrow range, above and below which deleterious effects of distinct nature occur. This review will deal with the formation of oxygen reactive species in iron participating reactions, defenses in the organism against these species, the different mechanisms of iron homeostasis and iron deficiency and iron overload related diseases.

Yeast lacking Cu-Zn superoxide dismutase show altered iron homeostasis. Role of oxidative stress in iron metabolism.

Saccharomyces cerevisiae lacking copper-zinc superoxide dismutase (sod1) shows a series of defects, including reduced rates of aerobic growth in synthetic glucose medium and reduced ability to grow by respiration in glycerol-rich medium. In this work, we observed that addition of iron improved the respiratory growth of the sod1 mutant and in glucose medium total intracellular iron content was higher in the sod1 mutant than in wild type cells. Transcription of the high affinity iron transporter gene, FET3, was enhanced in the sod1 mutant, suggesting that iron transport systems were up-regulated. An sod1/fet3 double mutant showed increased sensitivity to oxygen and increased transcription of FET4, an alternative, low affinity, iron transporter. We propose that this increased iron demand in the sod1 mutant may be a reflection of the cells' efforts to reconstitute iron-sulfur cluster-containing enzymes that are continuously inactivated in conditions of excess superoxide.

Charcoal deposits in the esophageal and gastric mucosa.

We report the case of a 75-yr-old woman referred for gastrointestinal endoscopy to investigate severe iron deficiency anemia. Black linear lesions were observed in the distal esophagus and stomach. Biopsies revealed aggregates of coarse black foreign material, which was later identified as charcoal. The patient's previous medical history included an antidepressant overdose 5 yr before the current admission. The patient had a gastric lavage, using a large bore orogastric tube, followed by the administration of activated charcoal. The patient had no other history of charcoal ingestion. We propose that the charcoal became entrapped in mucosal tears caused by the traumatic intubation 5 yr previously, causing the incidental mucosal tattooing seen at endoscopy.

[Treatment of lip angiomas]. / Tratamento dos angiomas do lábio.

The experience with the treatment of 25 patients with angiomas of the lips is presented. Among the several methods of treatment indicated in the literature, the authors have experimented with surgery, surgery and embolization, and systemic corticotherapy. Local application of corticosteroids and sclerosing agents were used just as a complementary therapy to the surgery. Surgery performed in one or more stages when necessary, were considered a safe and reliable method for treatment of mature venous angiomas, as well as for immature ones with no involution after a period of five years.

Embolization to reverse severe recurrent hepatic encephalopathy.

Five patients with porto-systemic shunts, four spontaneous and one surgically created, presenting severe recurrent hepatic encephalopathy rebel to clinical treatment were angiographically examined. A spontaneous splenic-renal veins shunt was observed in four cases and a mesocaval shunt was identified in the remaining patient. Two thirds embolization of the spleen was able to control hepatic encephalopathy in two patients. Percutaneous transhepatic portography and selective embolization of the shunt was performed in two other patients with good results. Percutaneous transcaval embolization of the mesocaval shunt succeeded to control hepatic encephalopathy in the remaining patient. Splenic embolization is able to control hepatic encephalopathy in patients with splenomegaly and spontaneous porto-systemic shunt. Direct embolization of the shunt is also able to control hepatic encephalopathy as should be expected.