Surgical considerations in bypassing coronary arteries with 100% proximal occlusion.

Objective data on the ability of cineangiography to predict the size of reconstituted totally occluded coronary arteries, as well as the clinical outcome of such revascularization, are sparse. Accordingly, we reviewed 200 consecutive cases of coronary revascularization to determine the answers to these questions. Group I patients (n = 57, with 86 totally occluded coronary arteries) had at least one coronary artery with a 100% proximal occlusion that reconstituted distally. Group II patients (n = 143, with 205 subtotally occluded coronary arteries) had 50% to 99% proximal stenosis of at least one coronary artery. Cineangiograms were blindly reviewed to measure the size of the coronary arteries, which were compared with the actual vessel size at operation. In group I, the totally occluded coronary arteries had a cineangiographic size of 1.9 +/- 0.7 mm and an actual size of 1.6 +/- 0.4 mm (p = 0.00004). In group II, the subtotally occluded coronary arteries had a cineangiographic size of 1.8 +/- 0.4 mm compared with an actual size of 1.8 +/- 0.3 mm (p = not significant). The site of bypass grafting was significantly smaller in group I (1.6 +/- 0.4 mm versus 1.8 +/- 0.3 mm; p = 0.00008). The two groups were similar with respect to preoperative and intraoperative parameters. Operative mortalities were similar (group I, 1.8%; group II, 3.5%; p = 0.68). Creatine kinase isoenzyme profiles and electrocardiographic changes were similar, except for a significant late rise of creatine kinase-MB in group I (56.1 +/- 14.7 versus 30.7 +/- 33.7 MIU/mL; p < 0.001). In conclusion, cineangiography significantly overestimates the size of totally occluded coronary arteries.(ABSTRACT TRUNCATED AT 250 WORDS)     

Different Regiospecificity in the Hydroxylation of the Antidepressant Desmethylimipramine Between Rat Brain and Liver

Abstract: Incubation of the tricyclic antidepressant desmethylimpramine (DMI) with rat liver or brain microsomes in the presence of NADPH or t-butyl-hydroperoxide (TBH) revealed different regiospecificities in the hydroxylation reactions between the tissues. In brain preparations 10-OH-DMI was formed in reactions supported by NADPH or TBH, whereas in the latter case also an unidentified metabolite could be detected. Inclusion of exogenous NADPH-cytochrome P450 reductase in the brain preparations caused a 10-fold higher rate of 10-hydroxylation but no 2-OH-DMI could be detected. By contrast, liver microsomal preparations in the presence of NADPH catalyzed formation of both 2- and 10-OH-DMI, whereas only 10-OH-DMI was formed in TBH-supported reactions. The results indicate that antidepressant drugs can be metabolized in brain with different stereospecificity as compared to liver.     

Acute changes in dopamine levels in rat adrenal glands after administration of dopamine receptor agonists and antagonists

The study was aimed at in vivo pharmacological identification of the possible dopamine (DA) receptor(s) involved in changes of the DA level in rat adrenal glands. Previous work in this laboratory has shown that the DA level is largely controlled by the rate of catecholamine synthesis. The rats were killed by decapitation after various periods of drug administration and the catecholamine content of adrenal glands and forebrain was measured by high-performance liquid chromatography with electrochemical detection. Administration of the DA D-1 + D-2 receptor agonist, apomorphine, induced a statistically significant increase in DA levels in the adrenal glands. The same effect was noted after administration of the DA D-2 receptor agonist, quinpirole. The DA D-2 receptor antagonist, raclopride, blocked the apomorphine-induced increase in adrenal DA levels but had no effect per se on these levels. The DA D-1 receptor agonist, SKF 38393, and the DA D-1 receptor antagonist, SCH 23390, did not have any effect on apomorphine-induced changes in DA content in the adrenals. The DA elevating effect of the DA D-2 receptor agonist, quinpirole, in the adrenals was completely blocked by the DA D-2 receptor antagonist, domperidone. This compound does not cross the blood-brain barrier readily and is thus supposed to act mainly on peripheral tissues. In support of this, the dose of domperidone used did not affect brain DOPAC levels. Our data, together with observations reported in the literature, indicate that the adrenal medulla contains DA receptors of the D-2 subtype, which are capable of controlling the DA level in rat adrenal glands.     

Clinical MR imaging with a Helmholtz-type surface coil

Limited-field-of-view radio-frequency receiver antennas provide improved near-field sensitivity for magnetic resonance imaging by decreasing the antenna volume. The Helmholtz-type surface coil, consisting of two flat rings, is an organ-encompassing antenna that takes advantage of this principle to yield an improved signal-to-noise ratio (S/N). The coil was tested in a group of 50 patients and 16 healthy volunteers. Images obtained with the Helmholtz coil demonstrated quantitatively superior S/N of 2.2-fold or greater than that of comparison body coil images, as well as qualitatively superior anatomic resolution.     

Periosteal transplantation to the rabbit patella

Autologous periosteal transplantation (without chondrocyte cell transplantation) for treating traumatic articular cartilage defects of the patella gives pain relief in uncontrolled clinical studies. To study the whole transplanted area macroscopically and microscopically, animal studies are motivated. In this pilot study, we reproduce the surgical technique for periosteum transplantation on human patella to a rabbit model. A full-thickness cartilage defect of the whole patella was created in eight adult female rabbits. The defect was treated with autologous periosteal transplantation. After surgery, the rabbits were allowed free activity. This is the difference compared to the treatment in humans, where our group uses CPM for 5 days and non-weight-bearing for 12 weeks. After 21 weeks, there was a diffuse synovitis in all transplanted knees, and in five of eight knees there were signs of osteoarthritis in the patello-femoral joint. Histologically, in three animals, small islands of hyaline cartilage surrounded by fibrocartilage were seen in the transplanted area. In the other five animals, fibrocartilage was the predominant tissue. In contrast to previous experimental studies using a rabbit model, we did not achieve hyaline cartilage resurfacing.     

Effect of low-level clenching and subsequent muscle pain on exteroceptive suppression and resting muscle activity in human jaw muscles.

OBJECTIVE: To investigate the effects of muscle fatigue induced by low-level isometric jaw-clenching and subsequent glutamate-evoked muscle pain on the exteroceptive suppression (ES) response and resting electromyographic (EMG) activities in human jaw muscles. METHODS: The resting EMG activity and the ESs were recorded before (baseline), after low-level jaw-clenching (Post1), after subsequent glutamate or isotonic saline injections into the left masseter (Post2), and 60 min after the clenching (Post3) in 23 healthy volunteers. RESULTS: The late ES (ES2) showed more inhibition at Post1 compared with baseline (P<0.05). It was less inhibited after both types of injections (Post2), and increased at Post3 again (P<0.05) with no significant difference between the glutamate and isotonic saline sessions. The resting EMG activity increased at Post1 and Post2 (P<0.05). The glutamate injection further increased the resting EMG activity in the injected muscle (P<0.01). CONCLUSIONS: Muscle fatigue influences inhibitory reflex pathways in jaw-closing muscles and subsequent acute muscle pain potentiates the local increase in the resting EMG activity of the painful muscle. SIGNIFICANCE: Muscle fatigue which can be observed in patients with oral dysfunctions may interact with nociceptive regulation and influence the clinical presentation of jaw symptoms and function.     

7β-(6-取代-2-喹诺酮-3-乙酰氨基)头孢菌素的合成

以6-取代-2-喹诺酮-3-乙酸为侧链,用CDI法和潘化酯法与7-ADCA,7-ACA,7-ACT,和7-ACD缩合,合成了16个新的7β-(6-取代-2-喹诺酮-3-乙酰氨基)头孢菌素类化合物,通过溶媒转提,葡聚糖凝胶(Sephadex LH-20)柱层析及离心薄层层析分离精制,得到纯品。初步体外抑菌试验表明:新化合物对革兰氏阳性及某些阴性菌具有高度敏感性。大多数化合物对所试试验菌的抗菌活性与头孢唑啉和青霉素G钠相当,有些比它们还强。