Determination of the valence of Pr, Gd, and Ho in YBa2Cu3O7 by x-ray absorption spectroscopy.
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Journal Article↗
Biomedical subjects
J Wong
Publications and source records attributed to J Wong.
Increased expression of the embryonic form of a developmentally regulated mRNA in Alzheimer's disease.
There is increasing evidence that an aberrant sprouting response may contribute to some of the neuronal alterations observed in Alzheimer's disease (AD). In this study, we demonstrate that in the rat CNS, sprouting results in the reinduction of the embryonic form of the mRNA for alpha-tubulin. The fetal form of alpha-tubulin mRNA was also elevated in the hippocampus obtained from five AD patients, as compared to five elderly controls. These results suggest that the reexpression of embryonic forms of cytoskeletal proteins, in association with an aberrant sprouting response, may contribute to the neuropathological alterations in AD.
Adult↗
Extended hepatectomy for hepatocellular carcinoma.
The results of extended hepatectomy in 25 patients with hepatocellular carcinoma performed over a 16 year period have been reviewed, analysed and compared with those of 144 patients who underwent lesser liver resection. Five left and 20 right extended hepatectomies were performed for tumours ranging from 3 to 20 cm in diameter. Seventeen (68 per cent) of the patients had non-cirrhotic livers. The major postoperative complications were: haemorrhage in five cases, major bile duct injury in three, subphrenic abscess in two, liver failure in one and wound dehiscence in one. The 30-day (operative) mortality rate was 12 per cent and the median survival duration, including operative mortality, was 9.7 (range 0.2-32.1) months. The survival rate was 46 per cent at 1 year, 33 per cent at 2 years and 22 per cent at 3 years. The morbidity, mortality and survival data of extended hepatectomy were comparable with the results of lesser hepatic resections for hepatocellular carcinoma. We conclude that extended hepatectomy is a worthwhile operation for large hepatocellular carcinomas and a viable alternative to liver transplantation.
Adult↗
Long-term results of resection for large hepatocellular carcinoma: a multivariate analysis of clinicopathological features.
Recurrent or metastatic disease is frequently encountered among patients who have had resection of their primary hepatocellular carcinoma. A retrospective study on 117 patients (104 men, 13 women; mean age +/- standard deviation: 53.8 +/- 12.4 yr) who had hepatectomy for large hepatocellular carcinoma (diameter greater than or equal to 5 cm) was conducted to identify an at-risk population for tumor recurrence. Disease-free survival was correlated with 22 clinical (n = 5), serological (n = 2), gross pathological (n = 3) and histological (n = 12) features of the resected specimens using Cox's multivariate regression analysis. Recurrent hepatocellular carcinoma was detected in 74 patients within a median follow-up period of 13.7 mo. Although 17 patients had extrahepatic disease alone, recurrence was confined to the hepatic remnant in 40 patients. Disease-free survival rates at 1, 3 and 5 yr were 40%, 19% and 12%, respectively. Two of the five histological parameters isolated, negative resection margin (p less than 0.01) and encapsulation (p less than 0.006), were identified as favorable independent prognostic predictors. When patients with positive margins were excluded from the analysis, repeated calculation showed that encapsulation was the only important determinant. From this analysis, detailed histological study of the resected tumor is seen to be the only satisfactory means for assessing long-term prognosis. An aggressive approach is warranted among patients with encapsulated tumors. Even with a clear resection margin, adjuvant treatment should be considered for those patients who have unencapsulated lesions.
Adult↗
Differential regulation of peripherin and neurofilament gene expression in regenerating rat DRG neurons.
Quantitative in situ hybridization and RNA blotting methods were used to define the time course and magnitude of changes in expression of mRNAs encoding peripherin and the neurofilament (NF) triplet proteins in rat dorsal root ganglion (DRG) neurons during axonal regeneration. mRNA levels in adult rat L4 and L5 DRGs were examined in autoradiograms after in situ hybridization with specific 35S-labeled cDNA probes 1-56 days following unilateral crush lesions of the sciatic nerve. The results of quantitative analyses indicated that peripherin mRNA levels were significantly increased in large-sized (greater than 1000 microns 2) DRG neurons at 7, 14, and 28 days after axotomy while the mRNA levels for each of the NF triplet proteins were significantly decreased at these same time points. The mRNA levels of the low (NF-L) and middle (NF-M) sized NF subunits were significantly decreased as early as 1 day postaxotomy but the mRNA level of the large NF subunit (NF-H) did not change until 7 days after axotomy. The maximal reduction in NF mRNA levels was observed at 14 days postaxotomy when NF-L mRNA levels were only 35% of those in large-sized, normal control neurons. Recovery toward normal levels of both NF and peripherin mRNAs was observed at 8 weeks postaxotomy. RNA blot analyses with total RNA obtained from DRGs at different postaxotomy times confirmed that NF-L mRNA levels were reduced in the DRG during the first 4 weeks after axotomy but, interestingly, failed to detect an increase in peripherin mRNA levels. This difference concerning peripherin mRNA levels in axotomized preparations obtained by RNA blotting vs. in situ hybridization was attributed to the fact that RNA blots utilized total DRG RNA which includes mRNAs from both small and large-sized DRG neurons. A recent in situ hybridization study showed that the small-sized DRG neurons which contain the majority of the peripherin mRNA in the DRG do not increase their peripherin mRNA levels 14 days after axotomy (Oblinger et al., 1989b). This may mask any change in the large neuron response when total RNA is examined. Overall, the results of this study demonstrate (1) that type III (peripherin) and type IV (NF) intermediate filament genes are regulated differently during axonal regeneration, and (2) that the three NF genes are down-regulated in a fairly coordinate manner during regeneration. These data suggest that an important component of the regeneration program is the alteration of the composition of the IF component of the cytoskeleton.(ABSTRACT TRUNCATED AT 400 WORDS)
Animals↗
Effect of laser irradiation on the dissolution kinetics of hydroxyapatite preparations.
This research investigated the effects of a laser irradiation treatment on the dissolution characteristics of hydroxyapatite (HAP), and the results provide an insight into the relationship between the effects of laser treatment and the two-site dissolution kinetics of HAP samples. The HAP samples prepared by aqueous precipitation and digestion at approximately 100 degrees C were irradiated with a CO2 laser (20-50 W) with a beam diameter of 14 mm for a total of 10-400 s. Dissolution rates of the laser-treated HAP samples were subsequently determined in acetate buffer (pH = 4.5, mu = 0.50) at various levels of partial saturation (0-24% with respect to the HAP thermodynamic solubility of pKsp = 116). The following were the important findings. The X-ray diffraction and the IR spectroscopy results suggested that the HAP crystalline structure was not changed by laser treatment. Laser treatment of HAP powder at 50 W for 400 s, however, caused an approximately 3.5-fold reduction in the specific surface area of HAP and reduced the initial dissolution rate of HAP in acetate buffer by a factor of approximately 22.9. Also, this laser treatment appeared to reduce the dissolution rate of HAP in 16 and 24% partially saturated acetate buffer from substantial levels to essentially zero. These results may be summarized as follows. Laser treatment of HAP results in a reduction in the dissolution rate and also a reduction in the specific surface area of this material. However, the dissolution rate reduction is significantly greater than the reduction in the specific surface area.(ABSTRACT TRUNCATED AT 250 WORDS)
Hydroxyapatites↗
Effects of an experimental program on post-hospital adjustment of early discharged patients.
This paper reports the results of a study evaluating the effects of an experimental program on post-hospital adjustment of early discharged patients after total hip arthroplasties. This experimental program consisted of patient teaching by means of a pamphlet and videotape, and regular home visits by a community health nurse. A significant difference was found between the experimental and control patients in perceived preparedness for discharge and post-hospital exercise compliance. The early discharged experimental patients demonstrated post-hospital objective and subjective functional capabilities equal to those of the control patients. This study is seen to have implications for nursing service and nursing education.
Activities of Daily Living↗
Expression, characterization, and purification of a phosphorylated rabies nucleoprotein synthesized in insect cells by baculovirus vectors.
A baculovirus expression vector (AcNPV3) derived from the nuclear polyhedrosis virus of Autographa californica (AcNPV) was prepared containing the complete coding region of the nucleoprotein (N) gene of rabies virus (Gif-sur-Yvette clone of the CVS strain). The gene was placed under the control of the AcNPV polyhedrin promoter and was expressed to high levels (66 mg N protein/liter of 2 x 10(9) cells) by the derived recombinant virus using a Spodoptera frugiperda cell line. Using available antisera, it was established that the antigenic characteristics of the N protein were similar by comparison with those of the native N protein of rabies virus. Characterization of the expressed protein established that, like the N protein of mammalian cell-grown CVS virus, the N protein was phosphorylated. The expressed rabies N protein induced antibodies in mice that reacted strongly with the rabies viral protein. The expressed nucleoprotein was recovered from the insect cells by differential centrifugation followed by ion exchange chromatography. The expressed rabies N protein represents a source of authentic protein suitable for virus diagnosis as well as structural studies.
Animals↗
An evaluation of the closed mouth mandibular block technique.
This randomised double-blind study compared the efficacy of the closed-mouth and the conventional mandibular block injection techniques in 200 patients requiring anaesthesia for tooth extractions. Results showed the success rate of inferior alveolar nerve anaesthesia with a single injection to be 97% in the conventional group, and 79% in the closed-mouth group. Within 5 min after the injection, 87% of the conventional group as compared with 55% of the closed-mouth group had lip numbness. The conventional and closed-mouth techniques, respectively, yielded 22% and 2% positive aspirations. Long buccal nerve anaesthesia during the closed-mouth injection was achieved in 71% of cases. Both techniques produced similar pain responses, as well as changes in blood pressure and pulse rate. The closed-mouth injection technique produced a greater variety of unexpected symptoms than the conventional. It was concluded that the conventional technique was more effective in blocking the inferior alveolar nerve, and was also faster in producing anaesthesia, but yielded more positive aspirations than the closed-mouth technique.
Adolescent↗
Emergency surgery for severe acute cholangitis. The high-risk patients.
Emergency surgery for patients with severe acute cholangitis carries formidable postoperative morbidity and mortality rates. A retrospective study was conducted on 86 consecutive patients who had exploration for the calculous obstructions to identify the high-risk population to guide better management. Septicemic shock was present in 55 patients before surgery. All patients had ductal exploration under general anesthesia. Additional procedures included cholecystectomy (n = 55), cholecystostomy (n = 5), and transhepatic intubation (n = 2). Complications and deaths occurred in 43 (50%) and 17 (20%) patients, respectively. Multivariate analysis on the 25 clinical (n = 14) and biochemical (n = 11) parameters evaluated yield the following five predictive factors (relative risk): the presence of concomitant medical problems (4.5); pH less than 7.4 (3.5); total bilirubin more than 90 mumol/l (3.1); platelet less than 150 x 10(9)/l (2.9), and serum albumin less than 30 g/L (2.9). In the presence of three or more albumin less than 30 g/L (2.9). In the presence of three or more risk factors, postoperative morbidity and mortality rates were 91% and 55%, respectively, which were significantly higher than those with two or less risk factors (34% and 6%, respectively). As thrombocytopenia developed even with transient hypotension, timely ductal decompression would improve outcome of these patients after surgery. For the high-risk population, application of nonoperative biliary drainage might be considered.
Acute Disease↗
A prospective study on fish bone ingestion. Experience of 358 patients.
A prospective study was performed on 358 patients to examine the diagnosis, management, and natural history of fish bone ingestion. All patients admitted with the complaint had a thorough oral examination. Flexible endoscopy under local pharyngeal anesthesia would be performed on patients with negative findings. Of 117 fish bones encountered, 103 were removed (direct removal, 21; endoscopic removal, 82) and 12 were inadvertently dislodged. One was missed and the other one necessitated removal with rigid laryngoesophagoscopy under general anesthesia. Morbidity (1%) occurred in patients with triangular bones in the hypopharynx, resulting in one mucosal tear and two lengthy procedures. Mean hospital stay was 7 hours. Prediction of the presence of fish bones by symptoms and radiograph was poor. The location of symptoms, however, was useful in guiding the endoscopist to the site of lodgment. Of patients who refused endoscopy, only one (2.8%) developed retropharyngeal abscess. As compared to those who received endoscopy, 31.8% had fish bones detected. As the yield of fish bone detected was also inversely related to the duration of symptoms, we strongly suspect that most of the unremoved fish bones would be dislodged and passed. However, because of the serious potential complication from fish bone ingestion, we believe that a combination of oral examination followed by flexible endoscopy is indicated in all patients. When triangular bones in the hypopharynx are encountered, rigid laryngoesophagoscopy should be considered. This protocol had safely and effectively dealt with the present series of patients.
Adult↗
Role of computed tomography in the management of recurrent pyogenic cholangitis.
A retrospective analysis was performed to define the indications and usefulness of computed tomography (CT) in the management of 62 patients with recurrent pyogenic cholangitis. When performed in 18 patients in the acute phase for persistent fever inexplicable by ultrasonography and cholangiography, CT scans identified the cause of sepsis to be liver abscesses (n = 7), impacted stones in left lateral segments (n = 3) and right posterior inferior duct (n = 1). When performed in 44 patients during remission, CT scans detected impacted intrahepatic stones as the cause of non-opacification of segmental bile ducts on cholangiograms (n = 15), demonstrated liver volume changes (segmental atrophy, n = 31; hypertrophy, n = 5), differentiated intrahepatic stones from pneumobilia (n = 5) and revealed stones in segregated intrahepatic bile ducts (n = 4). Overall 75.8% of CT scans showed valuable intrahepatic findings which were useful in guiding the appropriate treatment for the intrahepatic pathology. In the others without demonstrable intrahepatic pathology on CT, patients were adequately treated for common bile duct pathology alone. It is recommended that CT should be performed when ultrasonography and cholangiography cannot elucidate the cause of persistent fever, when the cholangiogram shows non-opacification of segmental bile ducts, or fails to demonstrate the cause of recurrent acute cholangitis, particularly in patients who have had previous bilio-enteric drainage procedures.
Adult↗
Growth factor-regulated pathways in epithelial cell proliferation.
Investigations of the pathways regulating normal growth of epithelial cells have revealed the existence of two major growth-factor signaling cascades required for proliferation. One pathway is activated by IGF-1 or high insulin concentration. The other is triggered by EGF, TGF alpha, or members of the FGF family, including the recently discovered epithelial-cell-specific growth factor, designated keratinocyte growth factor (KGF). Its expression pattern in vivo suggests that KGF plays an important normal physiologic role as a stromal effector of epithelial cell proliferation. Oncogenes, which represent constitutively activated forms of genes critically involved in growth-factor signaling pathways, specifically abrogate the requirement for mitogens of the EGF pathway. Examples of such genes include the erbB/EGF receptor and erbB-2, which encode structurally related receptor proteins and are often amplified and/or overexpressed in epithelial malignancies. Employing reduced stringency hybridization with v-erbB as a probe, we recently identified a third member of this receptor family, designated erbB-3. cDNA cloning revealed a predicted 148-kD transmembrane polypeptide with structural features similar to those of the EGF receptor. Normal erbB-3 expression in keratinocytes and glandular epithelium suggests its physiologic role in these cell types. Moreover, markedly elevated erbB-3 mRNA levels in certain mammary tumor cell lines suggest that increased erbB-3 expression may also play a role in some human epithelial malignancies.
Animals↗
A novel skeletal drug delivery system for anti-bacterial drugs using self-setting hydroxyapatite cement.
To solve the problem of delivering drugs to skeletal tissue at high enough local concentrations for desirable therapeutic effects, we report a novel approach using a self-setting hydroxyapatite cement, with cephalexin and norfloxacin as model drugs. After setting, the cement was transformed into hydroxyapatite with affinity for hard bone tissue. Continuous in-vitro drug release profiles from loaded cement pellets (0.9-4.8% by weight) in phosphate buffer at pH 7.4 and 37 degrees C followed the Higuchi equation.
Anti-Infective Agents↗
Results of surgical resection for hepatocellular carcinoma.
The results of surgical resection in 174 patients with hepatocellular carcinoma was studied. The patients included 147 male and 27 female with a mean age of 54 years. Serum alfa-fetoprotein was elevated in 74% and 67% had liver cirrhosis. The operative morbidity was 46.6% and 30 day mortality was 13.2%. The most common complications were hemorrhage and liver failure. The five and eight year survival rates were 15% and 12% respectively. Long survival of more than ten years was possible after resection of large tumours, even in patients with liver cirrhosis.
Adult↗
A comparison of peripheral and central axotomy effects on neurofilament and tubulin gene expression in rat dorsal root ganglion neurons.
The expression of major cytoskeletal protein mRNAs was studied in adult rat dorsal root ganglion (DRG) neurons after crushing either their central or peripheral branch axons. mRNA levels in DRG neurons were examined by quantitative in situ hybridization with radiolabeled cDNA probes specific for the low-molecular-weight neurofilament protein (NF-L) and beta-tubulin. The large-sized (greater than 1000 microns 2) neurons which give rise to myelinated axons in lumbar ganglia (L4 and L5) were studied 1 d through 8 weeks after either dorsal root or sciatic nerve crush. NF-L and beta-tubulin mRNA levels in axotomized DRG neurons were compared to those in contralateral control DRG neurons, as well as to those in normal (completely untreated) DRG cells. In the case of NF-L mRNA, changes were observed after central as well as peripheral branch axotomy and the time course and magnitude of changes were similar after both types of axotomy. NF-L mRNA levels initially decreased (first 2 weeks after crush) and then began to return towards control levels at longer survival times. Similar, but less pronounced, changes in NF-L mRNA levels also occurred in contralateral DRG neurons (which were uninjured); the changes in contralateral neurons were not simply a result of surgical stress since no changes in NF-L mRNA levels were observed in sham-operated DRG neurons. In the case of tubulin mRNA, changes were observed after central as well as peripheral branch axotomy by in situ hybridization, but the time course and magnitude of changes were different after each type of axotomy.(ABSTRACT TRUNCATED AT 250 WORDS)
Animals↗
Gangrene in esophageal substitutes after resection and bypass procedures for carcinoma of the esophagus.
In 760 resection and bypass procedures for esophageal cancer, 30 patients (3.9%) developed gangrene in the esophageal substitute. The incidence in resection cases was similar to those who were bypassed. The important factors in its development were the length and type of organ used as an esophageal substitute. Gangrene was almost exclusively seen when the upper anastomosis was in the neck; the lowest incidence occurred when stomach was used (1%), while the highest was seen with jejunum (11.3%) and colon (13.3%).
Anastomosis, Surgical↗
Severe acute cholangitis: the role of emergency nasobiliary drainage.
The role of emergency endoscopic nasobiliary drainage (NBD) in the management of severe acute cholangitis was evaluated by comparing the outcome of 15 patients who underwent the procedure as an initial treatment with that of 20 patients who underwent emergency surgery. Biliary sepsis was successfully controlled without complication in all 15 patients by the insertion of a 7F nasobiliary catheter through a limited papillotomy. Subsequent definitive elective treatment included endoscopic stone clearance (n = 6), common duct exploration (n = 8), and bili-enteric reconstruction (n = 1). Among the 20 patients who had surgical treatment, cholecystectomy (n = 11), cholecystostomy (n = 1), and transhepatic intubation (n = 1) were done in addition to common duct exploration. Although patients undergoing endoscopic NBD were significantly older (75.3 years vs 60.1 years; p less than 0.05) and more jaundiced (total bilirubin, 120.3 mmol/L vs 70.4 mmol/L; p less than 0.05), comparable morbidity (40% vs 65%) and mortality (6.7% vs 20%) was observed. Initial endoscopic NBD provides a safe and effective therapeutic option for the management of fulminant biliary sepsis. Among patients with complicated ductal anatomy, endoscopic NBD should first be attempted because, when successful, definitive reconstruction may be performed on an elective basis. The value of its routine application for all patients, however, remains to be validated by further clinical studies.
Acute Disease↗