Cerebrovascular reserve capacity in ischemia due to occlusion of a major arterial trunk: studies by Xe-CT and the acetazolamide test.

Classifications based on clinical and radiographic criteria have proved to be inadequate predictors of the course of cerebral ischemia or its response to therapy. In this study the cerebrovascular reserve capacity (CRC) of 46 patients with symptomatic cerebrovascular ischemia was studied by stable xenon-enhanced CT (Xe-CT) combined with the acetazolamide test. Fifteen patients had internal carotid artery (ICA) occlusion, 10 had ICA stenosis, 10 had middle cerebral artery (MCA) occlusion, and 11 had MCA stenosis. In the patients with chronic cerebral ischemia due to occlusive lesions of the ICA and MCA, the CRC was reduced most in those with MCA occlusion, followed, in descending order, by those with ICA stenosis, MCA stenosis, and ICA occlusion. Our results indicate that measurement of the CRC elucidates cerebral hemodynamic factors that cannot be detected by angiography in patients with chronic cerebral ischemia and that Xe-CT combined with the acetazolamide test is useful for this purpose.     

Properties of active magnesium flux across the small intestine of the guinea pig.

Steady-state net flux of Mg2+ was measured in everted preparations of guinea pig jejunum and ileum, and effects of anoxia, Na+ and Ca2+ concentration, ouabain, and Ca2+ channel blockers were examined. Uphill Mg2+ flux in the mucosal-to-serosal direction was seen in both intestinal segments, with the flux value being 1.5 times greater in the ileum than in the jejenum. The Mg2+ flux was 1.7 times greater than the net Ca2+ flux under the same experimental conditions. The Mg2+ flux was strongly dependent on oxygen and the presence of Na+ in the medium; both anoxia and total replacement of Na+ inhibited the flux by 90-100%. Also, ouabain added to the serosal side, and verapamil or D600 added to the mucosal side, inhibited the flux by about 90%. Inhibitory effects of both ouabain and Na(+)-free conditions were much greater for the Mg2+ flux than for the Ca2+ flux. A stepwise increase in Mg2+ concentration in a Na(+)-free mucosal solution caused a stepwise elevation of the mucosal negativity. The relative elevation of the evoked potential in response to Mg2+ concentration possessed saturable and linearly increasing components. Only the saturable component was found to be dependent on oxygen and sensitive to ouabain. Under the influence of ouabain and verapamil, the generation of the Mg(2+)-evoked potential was greatly inhibited. These findings suggest that Mg2+ is actively absorbed by the jejunum and ileum of the guinea pig, and that active transcellular transport involves a verapamil-sensitive entry step and Na(+)-dependent or ouabain-sensitive exit process which differs from Ca2+ extrusion mechanisms.     

Carinal resection and reconstruction for recurrent lung cancer

A patient with a recurrent tumor in the trachea adjacent to the right main bronchus was treated by surgical resection 19 months after undergoing surgery for the primary cancer. The patient had previously undergone right upper lobectomy for T1N0M0 stage I squamous cell carcinoma. A carinal resection was performed which included 4 rings of the trachea, 2 rings of the righ main bronchus, and 1 ring of the left main bronchus. Reconstruction consisted of an end-to-end anastomosis of the trachea and left main bronchus, and an end-to-side anastomosis of the right and left main bronchi. The postoperative course was uneventful, and at present the patient is healthy 12 months following reoperation.     

Palmar advancement flap with V-Y closure for thumb tip injuries

The palmar advancement flap with V-Y closure was used in two patients with thumb tip injuries. This technique allows more distal advancement of the flap than does a conventional palmar advancement flap and does not require skin graft coverage.     

Inhibitory effect of spiradoline, a kappa opioid receptor agonist, on Ca2+ induced contraction and the intracellular Ca2+ concentration in porcine coronary artery.

STUDY OBJECTIVE--The aim was to clarify the inhibitory effect of the selective kappa agonist, spiradoline, on coronary arterial smooth muscle in relation to the intracellular Ca2+ concentration. DESIGN--The inhibitory effect of spiradoline was investigated (1) on the contractile response of pig coronary artery to the readmission of Ca2+, following initial exposure to Ca2+ free medium and depolarisation with 40 mM K+; (2) on the intracellular Ca2+ concentration as assessed using the fluorescent calcium indicator fura-2. Relaxant responses to spiradoline in isolated porcine coronary artery strips contracted with K+ and prostaglandin F2 alpha were also examined. EXPERIMENTAL MATERIAL--Coronary arteries isolated from pigs of both sexes were used. The right and left circumflex coronary arteries were cut into 3 mm wide strips which were used to measure the change in contractile force and the intracellular Ca2+ concentration. MEASUREMENTS AND MAIN RESULTS--Prior treatment with spiradoline at 2 x 10(-6) mol.litre-1 or more inhibited the contractile response to the readmission of Ca2+ in porcine coronary artery exposed to Ca2+ free medium in the presence of high K+. Naloxone at 3 x 10(-4) mol.litre-1 did not reverse the inhibitory action of 2 x 10(-5) M spiradoline. Ca2+ induced contraction was inhibited completely by 10(-4) M spiradoline. Moreover, spiradoline caused relaxation in arterial preparations that had been contracted with K+ (15 to 25 mmol.litre-1) or prostaglandin F2 alpha (10(-6) to 3 x 10(-6) mol litre-1), greater relaxation being seen in the K+ induced contraction. The intracellular Ca2+ concentration was significantly lowered by 2 x 10(-5) M spiradoline. CONCLUSIONS--The relaxant response of coronary artery to spiradoline is, in part, attributable to interference with Ca2+ entry into the arterial smooth muscle.     

Electron microscopic study of monkey retina after photodynamic treatment

The purpose of this histological study was to determine the effects of photodynamic treatment, using a hematoporphyrin derivative and argon laser, on normal retinas of monkeys. Ten cynomolgus monkeys were treated with a hematoporphyrin derivative, given intravenously at a dose of 2.5 mg/kg. Forty minutes or 1 or 3 days after the injection, argon laser photoradiation was given over a 2.0-mm-diameter with a 10-min exposure and at an intensity of 40, 100, or 200 mW. The eyes were enucleated 1, 3, 4, 15, 18, 21, 35, or 38 days after the photoradiation and tissue samples were observed under a transmission electron microscope. The most fragile regions in the retina were the retinal nerve fibers, the outer segments of the visual cells, and the retinal pigment epithelium. Vascular endothelial cells were also fragile. The retinal capillary was easily obstructed, and the choriocapillaris was also occluded in an animal with severe retinal damage. The Mueller cells had the highest tolerance to the photodynamic treatment. Thus, exposing the normal part of the retina to light during photodynamic therapy should be avoided.     

Purification and characterization of human immunodeficiency virus type 1 nef gene product expressed by a recombinant baculovirus

We have constructed the recombinant baculovirus which expresses the human immunodeficiency virus type 1 negative factor (nef) gene. Spodoptera frugiperda cells infected with the recombinant virus produced a 27-kDa protein which reacted with rabbit antisera raised against a carboxy-terminal synthetic peptide of the Nef protein by immunoblot analysis. Labeling experiment showed that the recombinant Nef protein was myristoylated. The recombinant Nef protein was purified to near homogeneity by DEAE-Sephacel, phenyl-Sepharose 4B, blue-Sepharose, and Sephadex G-150 column chromatography. No detectable GTP binding activity was observed in the purified recombinant Nef product.     

Surgical treatment of acute pulmonary embolism--report of two cases

Two surgical cases of acute pulmonary embolism with severe cardiocirculatory impairment were reported. In the first case, emergent open pulmonary embolectomy with cardiopulmonary bypass was not effective, and multiple and organized emboli were indicative. In the second case, complete pulmonary thromboembolectomy was accomplished under extracorporeal circulation with remarkable hemodynamic improvement. It was suggested that urgent pulmonary angiography was necessary for definitive diagnosis and medical treatment, and that indications for pulmonary embolectomy included all patients with massive emboli in the main branches of the pulmonary artery. Monitoring of pulmonary arterial pressure was important to assess the effect of thrombolytic therapy, and the system of emergent cardiopulmonary bypass was required for immediate and effective cardiopulmonary resuscitation.