Structure-driven CO2 selectivity and gas capacity of ionic clathrate hydrates.

Ionic clathrate hydrates can selectively capture small gas molecules such as CO2, N2, CH4 and H2. We investigated CO2 + N2 mixed gas separation properties of ionic clathrate hydrates formed with tetra-n-butylammonium bromide (TBAB), tetra-n-butylammonium chloride (TBAC), tetra-n-butylphosphonium bromide (TBPB) and tetra-n-butylphosphonium chloride (TBPC). The results showed that CO2 selectivity of TBAC hydrates was remarkably higher than those of the other hydrates despite less gas capacity of TBAC hydrates. The TBAB hydrates also showed irregularly high CO2 selectivity at a low pressure. X-ray diffraction and Raman spectroscopic analyses clarified that TBAC stably formed the tetragonal hydrate structure, and TBPB and TBPC formed the orthorhombic hydrate structure. The TBAB hydrates showed polymorphic phases which may consist of the both orthorhombic and tetragonal hydrate structures. These results showed that the tetragonal hydrate captured CO2 more efficiently than the orthorhombic hydrate, while the orthorhombic hydrate has the largest gas capacity among the basic four structures of ionic clathrate hydrates. The present study suggests new potential for improving gas capacity and selectivity of ionic clathrate hydrates by choosing suitable ionic guest substances for guest gas components.

Treatment of a unicameral bone cyst in a dog using a customized titanium device.

A 4-year-old Shih-Tzu, referred for an enlarged left carpus, was diagnosed with a unicameral bone cyst. A customized titanium device was inserted into cystic lesion and fixed by titanium screws. Sufficient strength of the affected bone with the device inserted to maintain limb function was established after resection of contents of cystic lesion. There was no deterioration of the lesion of bone cyst, and acceptable function of the affected limb with no clinical signs of lameness was maintained during 36 months follow-up. The results of this study demonstrated that bone cyst curettage and use of a customized titanium device could provide an effective alternative treatment of huge lesion of unicameral bone cysts with the intent of preventing pathologic fractures.

Effects of 17beta-estradiol on chemically induced long-term depression.

In this study, we have investigated the effects of 17beta-estradiol (E2) on chemically induced long-term depression (LTD). LTD was induced by a brief application of N-methyl-D-aspartate (NMDA) or (R,S)-3,5-dihydroxyphenylglycine (DHPG), a group I metabotropic glutamate receptor agonist. Bath application of E2 alone potentiated population excitatory postsynaptic potentials. This potentiation was readily reversed by washing with control saline. The effect of E2 on NMDA-induced LTD was a conversion of LTD to long-term potentiation (LTP). An application of NMDA in the presence of E2 induced LTP. The induction of LTP was inhibited by an inhibitor of calcium/calmodulin dependent protein kinase (CaMKII). The results suggest that E2 potentiates NMDA receptor function and induces an increase in postsynaptic Ca2+ concentration. An increase in postsynaptic Ca2+ concentration activates CaMKII, leading to LTP. In contrast to NMDA-induced LTD, an application of DHPG in the presence of E2 induced significantly larger LTD. The results suggest that E2 potentiates an as yet unidentified process(es) in inducing LTD by an application of DHPG. The effects of E2 both on NMDA-induced and DHPG-induced LTD were suppressed by an estrogen receptor antagonist.

Experience with programmed steroid treatment with thymectomy in nonthymomatous myasthenia gravis.

BACKGROUND: The benefit of thymectomy in myasthenia gravis management is recognized but the perioperative course can fluctuate. The goal of this study was to assess the feasibility and clinical benefit of dose-escalated steroid therapy with thymectomy for nonthymomatous myasthenia gravis. METHODS: We reviewed the records of 69 myasthenia gravis patients who were followed up after undergoing transsternal thymectomy with extended anterior mediastinal dissection in our hospital between 1976-2000. Forty-eight patients in the programmed treatment group who had dose-escalated and de-escalated steroid therapy during the perioperative period comprised 17 patients with ocular myasthenia gravis and 31 patients with generalized myasthenia gravis. Clinical benefits and clinical remission, which was diagnosed when the patients were symptom-free without medications for at least 1 year, were compared with those of 21 patients in the occasional treatment group who received medications occasionally over the perioperative period. RESULTS: Postoperative respiratory failure and myasthenic crisis did not occur in the programmed treatment group but did occur in 6 patients in the occasional treatment group. Remission rates in the programmed treatment group (mean follow-up, 6.4 years) were 30% at 3 years, 38% at 5 years, and 46% at 10 years; rates in the occasional treatment group (mean follow-up, 9.6 years) were 25% at 3 years, 25% at 5 years, and 45% at 10 years. CONCLUSIONS: Programmed steroid therapy in patients with nonthymomatous myasthenia gravis is feasible and it provides clinical benefit when fluctuating symptoms occur during the perioperative period.

Real-time visualization of partial liquid ventilation in a model of acute lung injury.

BACKGROUND: To clarify the effects of partial liquid ventilation, we visualized and morphologically analyzed real-time alveolar recruitment in a model of acute lung injury. METHODS: Male Wistar rats were divided into 3 groups: a group that underwent hydrochloric acid aspiration and mechanical gas ventilation (ALI group, n = 15), a group that underwent acid aspiration and partial liquid ventilation beginning 90 minutes after acid aspiration (PLV group, n = 15), and a group that underwent mechanical ventilation without acid aspiration (control group, n = 5). The number of ventilated alveoli and the diameter of the largest ventilated alveolus in each of 10 high-power fields observed on fluorescence micrographs with a tracer of labeled albumin were determined and averaged from 90 to 210 minutes after acid aspiration. RESULTS: The number of alveoli in the PLV group significantly increased in comparison to that in the ALI group. The diameter of the largest alveolus in the PLV group decreased from 103.7 +/- 16.3 microm to 76.3 +/- 6.5 microm until the end of the experiment. This diameter was equivalent to that in the control group. CONCLUSIONS: The excellent alveolar recruitment suggests that liquid ventilation ameliorates ventilator-associated lung injury.

Scopulariopsis fungus ball.

We report on a 67-year-old woman with a rare Scopulariopsis fungus ball in the right middle lung lobe. Pathologic examinations after right middle lobectomy showed that the lesion contained a moniliaceous mold fungus that was cultured and identified as Scopulariopsis. The patient's postsurgery course was uneventful.

Surgical considerations for pulmonary actinomycosis.

BACKGROUND: Diagnosis and treatment of pulmonary actinomycosis is difficult without surgical intervention. METHODS: Thirteen patients (10 men, 3 women; mean age, 62 years) underwent pulmonary resection and were given a pathologic diagnosis of pulmonary actinomycosis at our institution between 1976 and 2001. To clarify when pulmonary actinomycosis should be suspected in patients and the role of surgical intervention, we reviewed preoperative clinical characteristics, computed tomography findings, surgical indication, operative procedure, postoperative clinical course, and outcome. RESULTS: Ten patients (77%) had poor oral hygiene. Twelve patients (92%) were symptomatic, and 10 patients (77%) had hemoptysis. The mean interval between radiographic identification of the abnormality and surgical intervention was 8 months (interquartile range, 3.25 to 8 months). Computed tomography findings in all cases included radiologic opacity with air bronchogram or a low attenuation area. Lung cancer was diagnosed initially because of computed tomography findings of spiculation or pleural indentation, and operation was required in 8 patients (62%). The others were diagnosed with chronic pneumonia, and surgical intervention became necessary because of recurrent hemoptysis or prolonged illness. Six patients underwent lobectomy; the others underwent partial resection or segmentectomy. Neither complication nor recurrence has occurred. CONCLUSIONS: When patients, particularly those with poor oral hygiene, show radiologic opacity with an air bronchogram or low attenuation area on the computed tomography scan, pulmonary actinomycosis should be considered and penicillin should be administered as diagnostic therapy. Surgical intervention may be necessary when frequent hemoptysis has no resolution or lung neoplasm cannot be ruled out.

Pleural gas gangrene secondary to esophageal injury by an ingested fish bone.

We report a 73-year-old woman with right pleural gas gangrene, treated successfully by thoracoscopic debridement. The clinical course and chest computed radiography and thoracoscopy findings suggested that her condition resulted from a relatively rare esophageal injury after she accidentally ingested a fish bone. Video-assisted thoracoscopic intervention has proved useful in cases involving pleural gas gangrene.