A study of microemboli monitoring of atherosclerotic thrombotic cerebral infarction and artery stenosis.

This study aimed to assess the relationship between the recurrence and prognosis of patients with acute middle cerebral artery infarction, atherosclerotic brain infarction, and the existence of microemboli. We continuously enrolled patients with acute atherosclerotic thrombotic cerebral infarction artery stenosis. We performed transcranial Doppler color ultrasound micro emboli monitoring, color Doppler ultrasound carotid artery tests, intracranial and carotid artery magnetic resonance angiography, impairment evaluation of nerve function, and registration of stroke recurrence and stroke mortality. Of the 49 patients enrolled in the study, 123 main arteries presented atherosclerotic stenosis or formed plaques, and 33 patients had symptomatic stenosis. Patients with symptomatic stenosis have a higher incidence of microemboli than patients with asymptomatic stenosis (P = 0.009). The microembolus-positive rate increased in patients with unstable plaques (P = 0.001). Patients who were microembolus-negative were more likely to show a neural function deficient NIHSS (National Institutes of Stroke Scale) score improvement than patients who were microembolus-positive at one week (P = 0.026). However, we found no significant difference between mRS (modified rankin scale) score (P = 0.319), relapse, and death (P = 0.179). The rate of microembolus-positivity increased in patients with atherosclerotic thrombotic cerebral infarction and unstable plaques. Patients who were microembolus-negative were more likely to show an improvement of neural function deficiency than patients with microembolus-positivity at one week (P = 0.026).

Enhanced fluorescence from CdTe quantum dots self-assembled on the surface of silver nanoparticles.

This paper presents an investigation on the fluorescent properties of semiconductor CdTe quantum dots (QDs) self-assembled on the surface of PVP (polyvinylpyrrolidone)-capped silver nanoparticles (NPs) by the ligand field effect. A significant 2.5-fold enhancement in the integrated fluorescence intensities, red shift of fluorescence peak, and obvious decrease of lifetime were observed in the CdTe QDs assembled on the Ag NPs in comparison with the pure CdTe QDs. The fluorescence enhancement factor and red shift were found to depend on the Ag NP concentration. The fluorescence enhancement was attributed to a highly localized electromagnetic field on the Ag NPs generated by the surface plasma and the change in the surface trap state of the CdTe QDs originating from plasma oscillations in the Ag NPs. It is first proposed that the surface passivation of CdTe QDs is also an important factor for metal-enhanced fluorescence. The surface defects of CdTe QDs can be modified by the Cd-O coordination interaction between the CdTe QDs and PVP molecules, which will cause the trap state density and luminescence lifetime to decrease. The surface passivation of CdTe QDs can also improve fluorescence quantum yield and lead to the red shift of the fluorescence peak. Compared with previous reports, the occurrence of the self-assembly of CdTe QDs on the surface of PVP-capped Ag NPs is fairly simple and easy. From a practical point of view, the combination of CdTe QDs with Ag NPs may lead to the fluorescence enhancement, which could be utilized in a variety of chemical and biological detection applications.

SPAG5 promotes proliferation and suppresses apoptosis in bladder urothelial carcinoma by upregulating Wnt3 via activating the AKT/mTOR pathway and predicts poorer survival.

Sperm-associated antigen 5 (SPAG5) is involved in various biological processes. However, the roles of SPAG5 in bladder urothelial carcinoma (BUC) are unknown. This study showed that upregulation of SPAG5 was detected frequently in primary BUC tissues, and was associated with significantly worse survival among the 112 patients that underwent radical cystectomy (RC). Up and downregulating the expression of SPAG5 enhanced or inhibited, respectively, the proliferation of BUC cells in vitro and in vivo, and suppressed or enhanced, respectively, apoptosis in vitro and in vivo. Moreover, SPAG5 increased the resistance of BUC cells to chemotherapy-induced apoptosis. Mechanistic investigations showed that SPAG5 promotes proliferation and suppresses apoptosis in BUC at least partially via upregulating Wnt3 through activating the AKT/mTOR signaling pathway. The importance of the SPAG5/AKT-mTOR/Wnt3 axis identified in BUC cell models was confirmed via immunohistochemical analysis of a cohort of human BUC specimens that underwent RC. Collectively, our data suggested that in patients with BUC who underwent RC, high SPAG5 expression is associated with poor survival. In addition, targeting SPAG5 might represent a novel therapeutic strategy to improve the survival of patients with BUC.

Total gastrectomy and small intestinal cholesterol synthesis in diabetic rats.

Cholesterol synthesis is increased two- to threefold in the small intestine of diabetic rats. We have observed, in three separate experiments, that the characteristic increase in small intestinal cholesterol synthesis (SICS) in diabetic rats was prevented by total gastrectomy. Food intake was increased twofold, and the small intestine hypertrophied in the gastrectomized diabetic animals. In normal animals, total gastrectomy resulted in only a very small increase in intestinal cholesterol synthesis. In hyperphagic lactating animals, total gastrectomy did not prevent the characteristic increase in SICS that is usually observed in this hyperphagic model. These results indicate that the effects of total gastrectomy on preventing an increase in SICS are relatively specific for the diabetic state. The mechanism by which total gastrectomy prevents the increase in intestinal cholesterol synthesis in diabetic animals is unknown. Vagotomy did not prevent the typical increase in intestinal synthesis in diabetic animals. Additionally, selectively removing either the antrum or fundus of the stomach did not prevent the increase in SICS in diabetic animals, indicating that the inhibition requires the removal of the entire stomach. It can be speculated that the stomach produces a substance that induces the increase in SICS observed in diabetic animals and that total gastrectomy removes this stimulatory substance.

Clay-based polymer nanocomposites: research and commercial development.

This paper reviews the recent research and development of clay-based polymer nanocomposites. Clay minerals, due to their unique layered structure, rich intercalation chemistry and availability at low cost, are promising nanoparticle reinforcements for polymers to manufacture low-cost, lightweight and high performance nanocomposites. We introduce briefly the structure, properties and surface modification of clay minerals, followed by the processing and characterization techniques of polymer nanocomposites. The enhanced and novel properties of such nanocomposites are then discussed, including mechanical, thermal, barrier, electrical conductivity, biodegradability among others. In addition, their available commercial and potential applications in automotive, packaging, coating and pigment, electrical materials, and in particular biomedical fields are highlighted. Finally, the challenges for the future are discussed in terms of processing, characterization and the mechanisms governing the behaviour of these advanced materials.

The interlayer swelling and molecular packing in organoclays.

Understanding the interlayer swelling and molecular packing in organoclays is important to the formation and design of polymer nanocomposites. This paper presents recent experimental and molecular simulation studies on a variety of organoclays that show a linear relationship between the increase of d-spacing and the mass ratio between organic and clay. A denser molecular packing is observed in organoclays containing surfactants with hydroxyl-ethyl units. Moreover, our simulation results show that the head (nitrogen) groups are essentially tethered to the clay surface while the long hydrocarbon chains tend to adopt a layering structure with disordered conformation, which contrasts with the previous assumptions of either the chains lying parallel to the clay surface or being tilted at rather precise angles.

Modified simple cold storage of rat livers with UW solution.

Rat livers were preserved with the conventional use of UW solution for 30, 42, and 48 hr and compared with livers in which the vascular bed was expanded with an additional 10 to 60 ml UW/100 g liver. The extra UW, expressed as % liver weight, was entrapped during final portal infusion by typing off the supra- and infrahepatic inferior vena cava. A beneficial influence of the vascular expansion was most pronounced in the 40% group, with 10/10, 5/10, and 3/10 long-term survivors following transplantation after 30, 42, and 48 hr preservation versus 3/10 and 0/10 after 30 and 42 hr in the 0% controls. In separate experiments, surrogate indices of preservation quality following reperfusion explained this effect. The 40%--and, to a lesser extent, 20%--livers had higher and more uniformly distributed portal blood flow, better tissue oxygenation, smaller increases in postperfusion liver enzymes, higher adenine nucleotides and energy charge, and less histopathologic evidence of hemorrhage and congestion. Pressure changes in the vena cava fluid sump in additional experiments indicated that retrograde infusion of the trapped UW solution occurred in all of the 10-60% groups during the first 6 hr with stable pressures of 1.5 to 3 cm H2O thereafter. Collectively, these data suggest that the much discussed selective vulnerability of the microvasculature of stored allografts is due in part (or principally) to its selective lack of long-term exposure to the UW solution, which drains out of the open vessels but not from the parenchyma. The potential clinical exploitation of this concept is discussed.

Localizing studies in patients with persistent or recurrent hyperparathyroidism.

Preoperative localizing studies are essential for patients with persistent or recurrent hyperparathyroidism requiring reoperation, because of loss of normal tissue planes and because the hyperfunctioning parathyroid tissue that remains is more likely to be situated in an ectopic position. The value of noninvasive and invasive localizing techniques was evaluated in 59 consecutive patients undergoing reoperation for persistent (40 patients) or recurrent (19 patients) hyperparathyroidism. Magnetic resonance imaging was performed in 17 patients; 11 results (65%) were positive, 3 (18%) were negative, and 3 (18%) were false-positive. Ultrasonography was performed in 52 patients; 29 (56%) were positive, 16 (31%) were negative, and 7 (13%) were false-positive. Computed tomography was performed on 41 patients; 19 (46%) were positive, 16 (39%) were negative, and 6 (15%) were false-positive. Thallium chloride 201-technetium 99m pertechnetate scans were used in 39 patients; 19 (49%) were positive, 11 (28%) were negative, and 9 (13%) were false-positive. One or more of these noninvasive tests was positive in 78% of the cases. Highly selective venous catheterization with measurement of immunoreactive parathyroid hormone concentration localized the abnormal parathyroid gland in 20 of 28 patients (71%) overall and in 8 of the 14 patients (57%) whose tumors were not identified by the noninvasive techniques. Since false-positive results were common, a combination of localizing studies was helpful in identifying the abnormal gland. Fifty-three of the 59 patients (90%) were successfully treated at the initial reoperation and three were successfully treated at a second reoperation. Advances in parathyroid localization have contributed to the improved surgical results in patients with persistent or recurrent hyperparathyroidism.

Experience with orthotopic rat liver transplantation.

300 orthotopic liver transplantations in rats were performed for a variety of reasons. Male rats including Lewis, ACI, Wistar, and SD, with a body weight of 150 to 400 g, were used as liver donors and recipients. A midline abdominal incision was performed in both donor and recipient animals. The donor's liver was perfused through the aorta abdominalis. The recipient's liver was flushed via the protal vein (PV) with 2 ml of lactated Ringer's solution immediately after occlusion of the PV to make intrahepatic blood enter the circulation. The bile duct was reconstructed by end-to-end anastomosis via a Teflon catheter. The cuff technique was applied to anastomoses of the infrahepatic vena cava (VC) and PV. The suprahepatic VC was anastomosed using either suture or cuff technique. The operative success rate was 92.7% (278/300) on the average and 1-week survival rate 88.4% (199/225) in isografting. The model proved reliable for studies of liver transplantation.

[Binding and interaction of histones and transcription factors on the promoter of hAMFR gene].

In this study, histone H1, core histones H2A-H2B and H3-H4 were purified from chicken erythrocytes by hydroxylapatile chromatography. The nuclear extract was prepared from HeLa cells. We investigated the binding and interaction of histones and transcription factors on the upstream sequence of human autocrine motility factor receptor (hAMFR) gene by gel shift mobility assay. We found that the binding of H1 on the promoter sequence of hAMFR gene was relatively stable. We propose that H1 plays an important role in stablizing chromatosome. We also found that histones and HeLa cell extract could form a ternary complex with the DNA template.

[Effects of the interaction between histone and hAMFR gene promoter on the transcription activity in vitro].

The effects of interaction between histones and human autocrine motility factor receptor (hAMFR) gene promoter on the transcription activity in vitro was investigated by using histones purified from chicken erythrocytes, HeLa cell nuclear extracts and heat-treated supernatants of Xenopus eggs. The results showed that the competitive binding of histones and transcription factors at the promoter of hAMFR gene was very important to the transcription in vitro. If a pre-initiation complex was formed with HeLa cell nuclear extracts on the promoter prior to nucleosome assembly, it would prevent nucleosome-mediated transcription repression. When the nucleosome was assembled on the promoter in advance, the transcription activity could be repressed. When histones and HeLa cell nuclear extracts were mixed in the reaction simultaneously, the transcription activity would depend on the relative amount of histones to that of HeLa cell nuclear extracts.

Cholesterol synthesis in bypassed segments of the small intestine in hyperphagic rats.

Previous studies have demonstrated that a variety of conditions that result in an increase in food intake lead to an increase in small-intestinal cholesterol synthesis. In the present study, it was determined whether hyperphagia induces an increase in cholesterol synthesis in segments of the small intestine excluded from contact with the food stream and whether this increase would occur in bypassed segments of the proximal or mid-small intestine. In hyperphagic diabetic rats, cholesterol synthesis is increased 91% in the proximal portion of the small intestine excluded from contact with nutrients. In lactating rats, another model of hyperphagia, cholesterol synthesis is increased 2.4-fold in midintestinal segments excluded from contact with the food stream and 2.9-fold in segments of the proximal intestine that have been bypassed. These observations demonstrate that the hyperphagia-induced increase in small-intestinal cholesterol synthesis will occur in portions of the small intestine, even if contact with the food stream is prevented. In addition, this data demonstrated that the mass of the bypassed portion of the small intestine is increased in hyperphagic animals. In diabetic animals, the weight of the bypassed proximal intestine is increased 2.1-fold, whereas in lactating animals the mass is increased 50% in the bypassed midintestine and 74% in the bypassed proximal small intestine. In conclusion, the present study suggests that circulating or neurologic factors, or both, play a role in stimulating intestinal cholesterol synthesis in hyperphagic animals. These findings also suggest that indirect factors play a role in the increase in intestinal mass associated with hyperphagia.

Thyroid cancer: the case for total thyroidectomy.

Since there are no prospective studies concerning the treatment of thyroid cancer, there continues to be a considerable disagreement about the 'best' or most appropriate form of surgical treatment for patients with papillary or follicular thyroid cancer. Some surgeons recommend selective treatment depending upon the type of thyroid tumor and stage of the disease. Some advocate thyroid lobectomy and isthmusectomy, some near total thyroidectomy, and some total thyroidectomy for patients with papillary and follicular thyroid cancer. Total thyroidectomy for thyroid cancer would be the treatment of choice for virtually all patients with thyroid cancers if it could be done without complications. We therefore reviewed 160 consecutive patients who had total thyroidectomy for suspected or proven thyroid cancer to determine the complication rate of total thyroidectomy. One hundred and three patients had primary operations, 57 had reoperations with completion of total thyroidectomy and 124 had thyroid cancer. Serious complications (i.e. vocal cord paralysis or hypoparathyroidism) included two cases of transient bilateral recurrent nerve palsy, two patients with presumed transient unilateral vocal cord paralysis, three recurrent laryngeal nerves that were purposely sacrificed because of invasion of the nerve, and one case of permanent hypoparathyroidism. Two other patients developed postoperative wound infections. Only one of the permanent complications, the case of permanent hypoparathyroidism, could have been avoided by a lesser procedure. The experienced surgeon can perform a total thyroidectomy with minimal morbidity, and this procedure has certain theoretical and practical advantages. It should not be done, however, if it will result in a significant complication rate and, in selected patients, it may be preferable to leave a small amount of thyroid tissue to protect the blood supply to the parathyroid glands or recurrent laryngeal nerve.

Effects of rapamycin on cultured hepatocyte proliferation and gene expression.

Rapamycin, a potent immunosuppressive drug that disrupts normal signal-transduction processes, inhibited hepatocyte proliferation without evidence of inherent cytotoxicity in rat hepatocytes cultured in conventional medium or in a medium enriched with epidermal growth factor. The antiproliferative effect was dose dependent, uninfluenced by the concentration of epidermal growth factor in the medium and long lasting after a brief exposure. The effect of rapamycin was unaltered by the concomitant presence of FK 506 in the medium, suggesting that different binding affinities of these two drugs or even a separate rapamycin binding site may exist. Hepatocytes harvested 12 and 24 hr after partial hepatectomy were progressively less responsive to the antiproliferative effect of rapamycin. The gene expression of transforming growth factor-beta was reduced under in vivo rapamycin treatment, but at the same time the gene expression of albumin and glyceraldehyde-3-phosphate dehydrogenase was unchanged or increased. The experiments confirm that rapamycin has inherent growth-control qualities, and they strengthen the hypothesis that the recently defined immunophilin network is central to many aspects of cellular growth control.

Screening for candidate hepatic growth factors by selective portal infusion after canine Eck's fistula.

Completely diverting portacaval shunt (Eck's fistula) in dogs causes hepatocyte atrophy, disruption of hepatocyte organelles, fatty infiltration and low-grade hyperplasia. The effect of hepatic growth regulatory substances on these changes was assessed by constantly infusing test substances for four postoperative days after Eck's fistula into the detached left protal vein above the shunt. The directly infused left lobes were compared histopathologically with the untreated right lobes. In what has been called an hepatotrophic effect, stimulatory substances prevented the atrophy and increased hepatocyte mitoses. Of the hormones tested, only insulin was strongly hepatotrophic; T3 had a minor effect, and glucagon, prolactin, angiotensin II, vasopressin, norepinephrine and estradiol were inert. Insulin-like growth factor, hepatic stimulatory substance, transforming growth factor-alpha and hepatocyte growth factor (also known as hematopoietin A) were powerfully hepatotrophic, but epidermal growth factor had a barely discernible effect. Transforming growth factor-beta was inhibitory, but tamoxifen, interleukin-1 and interleukin-2 had no effect. The hepatotrophic action of insulin was not altered when the insulin infusate was mixed with transforming growth factor-beta or tamoxifen. These experiments show the importance of in vivo in addition to in vitro testing of putative growth control factors. They illustrate how Eck's fistula model can be used to screen for such substances and possibly to help delineate their mechanisms of action.