Chitosan-based hydrogels to treat hydrofluoric acid burns and prevent infection.

There is an urgent need for treatments for hydrofluoric acid (HF) burns and their derivative problems that prevent hydrogen ion dissociation and fluoride ion binding to tissues. This study evaluated the ability of chitosan-based hydrogels combined with a buffer solution containing either boric acid or Tris and calcium gluconate (CHS-BA-CG and CHS-Tris-CG) to repair HF burn wounds and prevent wound infections. We assessed calcium release rates and biocompatability and constructed a mouse HF burn model to assess the tissue repair effects of the hydrogels. Finally, we performed disc diffusion tests from burn tissue and quantified the bacterial counts to assess the anti-infection properties of the hydrogels. Calcium was gradually released in the CHS-BA-CG and CHS-Tris-CG groups (73% and 43%, respectively, after 48 h). The cell viabilities at 48 h after HF burn in these groups were significantly higher than those in the phosphate-buffered saline (PBS) and CG-treated groups. Histopathological evaluation showed a clear boundary between the epidermal and dermal layers in both CHS-BA-CG and CHS-Tris-CG-treated groups, indicating their effectiveness in tissue repair. In the disc diffusion test, CHS-BA-CG and CHS-Tris-CG exhibited larger inhibition zones against Acinetobacter baumannii than those for PBS and CG. The bacterial counts on HF burn wounds were significantly lower in the CHS-BA-CG and CHS-Tris-CG-treated groups than those in the PBS and CG-treated groups. The in vitro studies demonstrated the biocompatibility and antimicrobial effects of the CHS-BA-CG and CHS-Tris-CG hydrogels. Both gels also demonstrated tissue repair and anti-infection effects. Thus, chitosan-based hydrogels may be candidates for HF burn therapy.

Successful treatment of methemoglobinemia in an elderly couple with severe cyanosis: two case reports.

INTRODUCTION: Methemoglobinemia should be considered in all cyanotic patients who remain unresponsive to oxygen therapy. Rapid diagnosis is very important in emergency cases. Here, we present the cases of two patients, a married couple, admitted to our hospital with methemoglobinemia after exposure to sodium nitrite. CASE PRESENTATION: Two patients, a married couple, presented with methemoglobinemia. The 72-year-old Taiwanese man and 68-year-old Taiwanese woman were referred to our hospital with dizziness and tachypnea. On examination, their mucous membranes were cyanotic, and their blood samples showed the classic 'chocolate brown' appearance. The man also reported having experienced twitching of his right arm for a few minutes before arrival at the hospital. The symptoms of both patients failed to improve in response to supplemental oxygen delivered via oxygen masks, although the arterial blood gas data of these patients were normal and their pulse oximetry showed oxyhemoglobin levels of approximately 85%. A carbon monoxide-oximeter showed that the man's methemoglobin concentration was 48.3%, and the woman's was 36.4%. Methylene blue (100mg) was administered intravenously to both patients, and their symptoms improved dramatically. They were admitted to the intensive care unit and discharged three days later, without neurological sequelae. CONCLUSION: Severe methemoglobinemia is a life-threatening condition and, if untreated, may result in death. Early diagnosis and appropriate antidotal treatment are crucial in treating this emergency situation.

DPI-3290 [(+)-3-((alpha-R)-alpha-((2S,5R)-4-Allyl-2,5-dimethyl-1-piperazinyl)-3-hydroxybenzyl)-N-(3-fluorophenyl)-N-methylbenzamide]. II. A mixed opioid agonist with potent antinociceptive activity and limited effects on respiratory function.

Allyl-2,5-dimethyl-1-piperazines have been of interest as analgesic agents for the management of moderate-to-severe pain. In this study, we compared the antinociceptive properties and respiratory depressant activity of one such agent, (+)-3-((alpha-R)-alpha-((2S,5R)-4-allyl-2,5-dimethyl-1-piperazinyl)-3-hydroxybenzyl)-N-(3-fluorophenyl)-N-methylbenzamide (DPI-3290), with those of established narcotic analgesics, morphine and fentanyl. Intravenous administration of DPI-3290 in conscious laboratory rats increased antinociception in a dose-dependent manner with a corresponding ED(50) value of 0.05 +/- 0.0072 mg/kg. Simultaneous measurement of arterial blood gas in animals treated with DPI-3290 demonstrated dose-dependent increases in pCO2 with an ED(50) value of 0.91 +/- 0.22 mg/kg. In comparison, morphine and fentanyl increased antinociception in rats with ED(50) values of 2.01 +/- 0.0005 and 0.0034 +/- 0.00024 mg/kg, respectively, and the ED(50) value for morphine-induced changes in pCO2 was 4.23 +/- 0.72 mg/kg, whereas the ED(50) value for fentanyl-induced changes in pCO2 was 0.0127 +/- 0.0035 mg/kg. A separate series of experiments were designed to examine the effects of DPI-3290 on mu-opioid receptor induced antinociception and hypercapnia. Intravenous bolus doses of DPI-3290 that ranged from 0.2 to 1.0 mg/kg had no effect on antinociception mediated by alfentanil (2 microg/kg/min i.v.) but reduced hypercapnia by approximately 50%. Results from these studies demonstrate the equivalent antinociceptive efficacy of DPI-3290, morphine, and fentanyl but dramatic differences in the hypercapnia that antinociceptive doses of these drugs produce. When measured simultaneously, DPI-3290 had an 18.2-fold difference in the ratio comparing the ED(50) value for antinociception with the ED(50) value for changes in pCO2; this ratio was 2.1 for morphine and 3.7 for fentanyl. Furthermore, DPI-3290 reduced the alfentanil-mediated hypercapnia without any effect on antinociception. Together, the balanced opioid agonist activity of DPI-3290 may provide a means of powerful analgesia while mitigating the mu-opioid receptor-mediated hypercapnia.