Characterization of dehydrochlorinated poly(vinylidene chloride) and the shock-compressed material

Dehydrochlorinated poly(vinylidene chloride) proved to be a conjugated polyene-polyene polymer. Shock compression of the polymer formed a large portion of graphite and trace amounts of diamond and of an unknown carbon. The unknown carbon belongs to the hexagonal crystal system and possesses the cell dimension α₀ = 0.338 nm. A comparison with known carbynes was made in terms of the crystalline parameters.     

POSSIBLE PARTICIPATION OF NMDA AND GLYCINE RECEPTORS BUT NOT GABAA RECEPTORS IN ENFLURANE-INDUCED OPISTHOTONUS IN MICE

1. We previously reported that volatile anaesthetics produce incidences of a transient opisthotonus in mice, a sign of CNS stimulation. This study was performed to investigate mechanisms by which enflurane-induced opisthotonus (EIO) occurs. 2. The effects of pretreatment of N-methyl-d-aspartate (NMDA) antagonists dizocilpine (MK-801; DIZ) and ketamine (KET), GABA_A antagonists picrotoxin (PIC), pentylenetetrazol (PTZ) and glycine antagonist strychnine (STR) on the incidence of EIO were determined. Prior to exposure to 2.0% enflurane in air, male ddN mice were given intraperitoneal injections of 0.2 mL saline (control), 0.5–5.0 mg/kg DIZ, 20–80 mg/kg KET, 2.9 mg/kg PIC, 40.0 mg/kg PTZ and 0.75 mg/kg STR. After the injection, the behavioural state of the mice was observed for 20 min (the pre-enflurane period). During the exposure to enflurane the time for immobilization, that is, anaesthetic induction time (IT), and the incidence of EIO were measured. 3. Dizocilpine (1.0–5.0 mg/kg) and KET (80 mg/kg) significantly (P<0.01) reduced both the incidence of EIO and IT in a dose-dependent manner. During the pre-enflurane period DIZ produced incidences (5–40%) of transient seizures in a dose-dependent manner, while KET did not induce them at all. The two GABA_a antagonists had no detectable effect on the EIO. Strychnine significantly enhanced the EIO. These CNS stimulants resulted in a 3–10% incidence of transient seizure and/or opisthotonus during the pre-enflurane period, but there was no correlation between DIZ-induced seizure and EIO. 4. These results suggest that the EIO is mediated by the NMDA and the STR-sensitive glycine receptors, but not the GABA_A receptor. We speculate that DIZ acts on the NMDA-receptor and/or disrupts the balance between the inhibitory and the excitatory systems.     

Long-term follow-up studies in 211 patients with tetralogy of Fallot after corrective surgery over 10 years

A total number of 427 patients with tetralogy of Fallot who underwent corrective surgery between 1960 and March 1990, in whom 211 patients who survived the surgery over 10 years were evaluated for the follow-up studies. Hemodynamic and cardiac function studies were carried out in 101 patients at the mean interval of 15.7 years (ranges 2 to 21 years). Three methods indicated that patients with muscle resection and pulmonary valvulotomy without patch enlargement (NP) had worse results than the groups with RV patch below valve (RP) and with transannular patch (TP). Also, Holter ECG revealed ventricular arrhythmias in patients with NP were more common than the groups with RP and TP. Sixteen patients (13 with NP, 2 with TP and one with RP) were required reoperation for residual ventricular shunt in 13, residual pulmonary stenosis in 11 and tricuspid regurgitation in 2. All of these 16 patients survived operation and obtained excellent clinical status. It is concluded that patients with TOF after corrective surgery should be carefully followed with short term interval to prevent sudden death and postoperative complications.     

Surgical repair and long-term results in ruptured sinus of Valsalva aneurysm

Thirty-one patients with a ruptured sinus of Valsalva aneurysm (SVA) were operated on between January, 1961, and December, 1987. Twenty-five patients (81%) were in New York Heart Association (NYHA) Functional Class III or IV. Coexistent cardiac anomalies included a ventricular septal defect (VSD) in 16 patients (52%) and aortic valve regurgitation in 12 patients (39%). The ruptured SVA originated from the right coronary sinus in 29 patients (94%) and the noncoronary sinus in 2 patients (6%), and drained into the right ventricle in 30 patients (97%). In 6 patients treated recently, we used patches to repair the ruptured SVA and VSD through a double approach, thereby avoiding a ventriculotomy. This method resulted in no recurrent rupture or residual VSD postoperatively. There was one operative death (3%) and 4 late deaths (13%). Of the 26 surviving patients, 22 (85%) were in NYHA Class I at follow-up ranging from 6 months to 26.7 years (mean, 11.1 years). Actuarial survival at 25 years is 85.6 +/- 7.4% (mean +/- standard deviation). Repair of ruptured SVA with a patch through a double approach provides an excellent operative procedure and offers a long-term outcome.     

The role of gallium 67 imaging in non-Hodgkin's lymphoma of the gastrointestinal tract

To evaluate the clinical usefulness of gallium 67 imaging in the detection of gastrointestinal (GI) non-Hodgkin's lymphoma (NHL) and in the assessment of the therapeutic effects, images were reviewed in 24 cases (25 lesions: stomach, 20; ileum, 2; and terminal ileum and/or cecum, 3) and were compared using barium studies and, in 16 cases, computerized tomography (CT). In all, 23 (92.0%) of the 25 lesions were detected by⁶⁷Ga citrate imaging, the barium studies detected all 25, and CT detected 15 of 16 lesions (93.8%). The two lesions not identified by imaging and the one not found by CT were the smallest of all. In 2 (8.7%) of the 23 lesions positively identified by⁶⁷Ga-citrate imaging, both CT and imaging revealed the extent of the tumor more accurately than did the barium studies. In all but one of the patients, a close correlation existed between the imaging results and the therapeutic effects. These data suggest that⁶⁷Ga imaging is useful in conjunction with CT and barium studies for the detection of GI NHL and for the assessment of both the spatial extent of disease and the therapeutic effects, although a lack of⁶⁷Ga uptake after therapy does not always indicate a good therapeutic effect.     

Intraocular kinetics of ceftazidime (Modacin).

The concentration of ceftazidime was determined in the aqueous humor and the vitreous body of normal, vitrectomized and aphakic/vitrectomized eyes and in the serum of albino rabbits 1 h after intravenous injection of 100 mg/kg ceftazidime. The intravitreal ceftazidime concentration was low (0.1-0.2 microgram/ml) in normal eyes 1 h after intravenous injection, and high (8.7 +/- 8.5 micrograms/ml) in vitrectomized and aphakic/vitrectomized eyes when injected immediately after surgery. The ceftazidime concentration was also determined in the aqueous humor and the vitreous body of normal eyes and in the serum of albino rabbits 3, 6, 12, 24 and 48 h after intravitreal injection of 200 micrograms. The intravitreal ceftazidime concentration after intravitreal injection decreased exponentially for 12 h (half-life about 7.4 h). It decreased more slowly thereafter and remained at 13.0 micrograms/ml (mean) even 48 h after injection. This concentration exceeded the minimum inhibitory concentrations against common gram-positive and gram-negative organisms causing endophthalmitis.     

Climbing exercise increases bone mass and trabecular bone turnover through transient regulation of marrow osteogenic and osteoclastogenic potentials in mice.

To investigate the relationship between the effects of bone turnover and bone marrow cell development in bone cells, we developed a mouse voluntary climbing exercise model. Climbing exercise increased bone volume and transient osteogenic potential of bone marrow. This model would be suitable for investigating the mechanistic roles of mechanical loading. INTRODUCTION: The relationship between bone mass gain and local bone formation and resorption in mechanically loaded bone is not well understood. MATERIALS AND METHODS: Sixty-five C57BL/6J mice, 8 weeks of age, were assigned to five groups: a baseline control and two groups each of ground control and climbing exercise mice for 2 and 4 weeks. Mice were housed in a 100-cm tower and had to climb toward a bottle placed at the top to drink water. RESULTS: Compared with the ground control, bone mineral density of the left femur increased in the climbing mice at 4 weeks. At 2 and 4 weeks, bone formation rate (BFR/BS) of periosteal surface, the cross-sectional area, and moment of inertia were increased in the climbing mice, whereas BFR/BS and eroded surface (ES/BS) of endosteal surface did not differ. The trabecular bone volume (BV/TV) of the proximal tibia increased in climbing mice, and osteoclast surface (Oc.S/BS) and osteoclast number decreased at 2 weeks. At 4 weeks, there were increases in BV/TV and parameters of bone formation, including mineralized surface, mineral apposition rate, and bone formation rate. In marrow cell cultures from the tibia, the number of alkaline phosphatase+ colony forming units-fibroblastic and the area of mineralized nodule formation in climbing mice were increased, and the number of osteoclast-like TRACP+ multinucleated cells was lower at 2 weeks. At 4 weeks, these parameters recovered to the levels of the ground controls. CONCLUSION: Our results indicate that climbing increased trabecular bone volume and reduced bone resorption, with a subsequent increase in bone formation. Intermittent climbing downregulates marrow osteoclastogenic cells and upregulates osteogenic cells initially, but further exercise seemed to desensitize them. Cortical envelopes were enlarged earlier, but the response seems to differ from trabecular bone.