Application of multi-walled carbon nanotubes functionalized with hemin for oxygen detection in neutral solution

Functionalization of multi-walled carbon nanotubes (MWNTs) is of paramount importance for developing new sensors. In this study, a hemin-modified MWNT electrode was successfully constructed. Upon saturation, the amount of adsorbed hemin is estimated as 2.7 × 10^?9 mol cm^?2, which is 39 times larger than the value of the hemin monolayer. The electrochemical behavior of the hemin-modified MWNT electrode has been characterized by cyclic voltammetry (CV). The electron-transfer coefficient (α) is found to be 0.38 with a heterogeneous electron transfer rate (k) of 2.9 s^?1 for the adsorbed hemin. Both MWNT and hemin-modified MWNT electrodes show ideal reversibility in 5 mM K₃[Fe(CN)₆] in the range of 0.02–1.00 V s^?1, indicating fast electron-transfer kinetics. CV of the hemin-modified MWNT electrode in pH 7.4 phosphate buffer solution (PBS) clearly shows the dioxygen reduction peaks close to 0 V (vs. Ag|AgCl). These results are useful in the development of a novel oxygen sensor for working at a relatively low potential.     

EFFECTS OF DC-015, A NOVEL POTENT AND SELECTIVE α1-ADRENOCEPTOR ANTAGONIST ON PLASMA LIPID AND VASCULAR REACTIVITY IN HYPERLIPIDAEMIC RATS

1. The effects of DC-015, a newly synthesized quinazoline derivative, on plasma lipids, lipoprotein levels and vascular reactivity were investigated in Wistar-Kyoto rats (WKY) and spontaneously hypertensive rats (SHR). 2. The hypotensive effect of DC-015 was compared with prazosin in SHR. Intravenous administration of DC-015 and prazosin (both at 0.01, 0.05 and 0.1mg/kg) induced dose-dependent reductions in mean arterial pressure (MAP) which reached a maximal effect 5 min after injection and persisted over 2 h in SHR. DC-015 decreased MAP with equal efficiency compared with prazosin. 3. The plasma levels of total cholesterol (CE), low-density lipoprotein (LDL)-CE and total triglyceride (TG) were markedly increased and the levels of high-density lipoprotein (HDL)-CE were markedly decreased in both high fat-high cholesterol (HF-HC) diet fed WKY and SHR. 4. In HF-HC diet fed WKY and SHR, the total plasma CE, LDL-CE and total plasma TG were significantly reduced after oral administration of DC-015 (1 mg/kg, twice a day) for 4 weeks. Furthermore, DC-015 therapy was associated with increased HDL-CE levels and thus the ratio of total CE to HDL-CE was improved. The antihyperlipidaemic effect of prazosin was less than that of DC-015. 5. Significantly attenuated median effective concentration (EC₅₀) values and augmented maximal responses for phenyl-ephrine-induced contraction of aortic rings were observed in HF-HC diet fed WKY and SHR. Endothelium-dependent relaxation to acetylcholine was impaired while endothelium-independent relaxation to nitroglycerin was well preserved. 6. Oral administration of DC-015 (1 mg/kg, twice a day) for 4 weeks significantly augmented EC₅₀ values and attenuated maximal responses for phenylephrine-induced contraction of aortic rings in HF-HC diet fed WKY and SHR. Prazosin (1 mg/kg, twice a day) showed a lesser extent of efficiency than DC-015 at normalization of vasorelaxation in HF-HC diet fed WKY and SHR. 7. It is concluded that DC-015, a potent antihypertensive agent, may have additional advantage in also reducing hyperlipidaemia.     

Prognostic Factors in Patients with Bulky Stage IB or IIA Cervical Carcinoma Undergoing Neoadjuvant Chemotherapy and Radical Hysterectomy

All patients with bulky (≥4 cm) Stage Ib or IIa cervical carcinoma treated at Chang Gung Memorial Hospital between August 1988 and December 1991 using a strategy of neoadjuvant chemotherapy with cisplatin, vincristine, and bleomycin and radical hysterectomy were reviewed. Fifty-nine evaluable patients received 1 to 3 courses of chemotherapy, and 51 underwent subsequent hysterectomy. The remaining 8 patients, not completing planned surgery, were treated with definitive radiotherapy. The overall clinical response rate was 81.4% (48/59) with 18.6% complete response. Clinical response to chemotherapy was not different by stage, histologic type, tumor size, level of squamous cell carcinoma antigen, or DNA ploidy. However, tumors with DNA indices (DI) greater than 1.3 were associated with higher clinical response rates than tumors with DI ≤ 1.3 (P= 0.043). Histologically proven pelvic node metastases was noted in 18.5% (10/54) who had laparotomy. Concomitant pregnancy and more than one node metastases had significant adverse influence on recurrence and death. The 5-year survival rate of those patients who received hysterectomy was 80.3%, while only 1 of the 8 patients without hysterectomy survived. Of the 7 patients received hysterectomy despite clinical poor response, only 2 had node metastases and 3 died, whereas all the 4 patients deterred hysterectomy for poor response died. This study demonstrates the value of DNA flow cytometry in predicting chemosensitivity. However, with a DI cutoff at 1.3, only 29.2% patients could be selected. Further studies are necessary to find additional indicators that predict histological response to select better candidates for this approach and to determine optimal adjunctive treatment in case that poor prognostic features are found.     

Macular subretinal neovascularization in choroidal tuberculosis

A 54-year-old Chinese woman with miliary choroidal tuberculosis was followed for more than three years. She had had tuberculous meningitis for about one month before an ophthalmologic examination for blurred vision OU. There were 50 to 60 choroidal tubercles OU which were located mostly at the posterior poles including the macular areas. The meningitis and tubercular lesions resolved with antituberculous medications. In a series of fundus photographs and fluorescein angiograms, a macular subretinal neovascularization was noted in association with the tubercular lesions which resulted in disciform maculopathy. To the best of our knowledge, this case had the largest number of tubercles reported in this century, and the association of macular subretinal neovascularization with choroidal tuberculosis has never been reported.     

Glial glutamate dehydrogenase: ultrastructural localization and regional distribution in relation to the mitochondrial enzyme, cytochrome oxidase

Glutamate dehydrogenase (GDH) is primarily a mitochondrial enzyme involved in the metabolism of glutamate. We have recently shown by light microscopic immunocytochemistry that, within detergent-permeabilized brain tissue, GDH is enriched in glial cells, particularly in regions utilizing L-glutamate as a neurotransmitter. In this study, we used immunogold labeling to quantitatively establish that the form of the enzyme recognized by the presently used GDH antiserum is associated primarily with a subpopulation of mitochondria in ultrathin, plastic-embedded sections of the rat cortex and striatum. Permeabilization with detergents was omitted in these studies, so as to preserve the ultrastructure. As expected, labeled mitochondria occurred both in neurons and glia. Furthermore, light microscopic comparisons of the regional distributions of peroxidase immunoreactivity for GDH and a histochemical reaction product for a second mitochondrial enzyme, cytochrome oxidase (CO), were used to demonstrate that high levels of GDH in glia of glutamate-receptive areas do not necessarily reflect the areas' demand for elevated oxidative metabolism. While all regions showing intense labeling for glial GDH also exhibited high levels of CO activity, many additional regions showing high levels of CO activity contained no detectable immunoreactivity for glial GDH. These light-microscopic comparisons reveal that the energy requirements are not the only factors accounting for the regional heterogeneity of the enzyme. We conclude that glial mitochondria are heterogeneous with respect to their GDH content and that GDH is enriched in areas exhibiting chronically active glutamatergic transmission.     

Ultrasonography of small hepatic tumors using high-resolution linear-array real-time instruments

Abdominal ultrasonography using a high-resolution linear-array real-time scanner was compared to computed tomography, celiac arteriography, and radionuclide imaging in 24 patients with a total of 33 hepatocellular carcinomas (HCC), 10 patients with cavernous hemangioma (12 tumors), and 2 patients with metastatic carcinoma of the liver (3 tumors), all smaller than 3 cm. Ultrasound proved to be the most sensitive method of detecting such small tumors. Most small HCCs were hypoechoic and most small hemangiomas hyperechoic. Aspiration cytology and/or biopsy under ultrasound guidance detected 92.3% of HCCs and 100% of hemangiomas. Intraoperative ultrasound was employed in 19 cases of small HCC and aided resection in 8. Real-time ultrasound may play a prominent role in early detection and diagnosis of small HCCs.     

The vesicle-associated membrane protein family of proteins in rat pancreatic and parotid acinar cells

BACKGROUND & AIMS: The vesicle-associated membrane protein (VAMP) family of proteins may play an important role in regulating enzyme secretion from pancreatic and parotid acini. The purpose of this study was to characterize the isoforms produced in pancreatic and parotid acini and determine their subcellular locations. METHODS: Using a battery of specific antisera and recombinant tetanus toxin light chain (which cleaves VAMP-2 and cellubrevin), the presence of each VAMP molecule in the acini was determined by immunoblotting of subcellular membrane fractions; their localization was determined by confocal immunofluorescence microscopy and immunogold electron microscopy. RESULTS: Both VAMP-2 and cellubrevin were present on both the zymogen granule membrane and plasma membrane. VAMP-1 was not present in the acinar cell but was found in the nerve endings innervating the acini. As expected, pancreatic acinar VAMP-2 and cellubrevin were sensitive to cleavage by recombinant tetanus toxin. CONCLUSIONS: VAMP-2 and cellubrevin may play integral roles in exocytosis of the pancreatic and parotid acinar cells, whereas VAMP-1 is restricted to nerves that innervate the acini and may function to modulate exocrine activity. (Gastroenterology 1996 Dec;111(6):1661-9)     

Characterization and nucleotide sequences of the variable regions of a monoclonal antibody against alpha-fetoprotein.

alpha-Fetoprotein (AFP) is a well-known tumor marker of hepatocellular carcinoma (HCC). Monoclonal antibodies against AFP possessing specific binding ability to HCC are potential candidates for immunoscintigraphy and immunotherapy. A new monoclonal antibody against AFP (0325-6-9) was isolated. Its specificity and targeting tumor ability were characterized by enzyme-linked immunosorbent assay (ELISA), cell immunostain and complement killing. These results suggest that 0325-6-9 is specific to hepatoma cells. The nucleotide sequences of variable regions of 0325-6-9 were determined by M13 dideoxynucleotide sequencing method. With the information of nucleotide sequence, this antibody then could be modified by recombinant technology for its usage in in vivo diagnosis and immunotherapy.     

Experience with treatment of gastroschisis and omphalocele.

From 1982 to 1990, 31 neonates with omphalocele and 54 with gastroschisis were treated at Mackay Memorial Hospital. The overall survival rate for omphalocele was 71%, while it was 85% for gastroschisis. The rate of primary fascial closure for omphalocele (85%) and gastroschisis (87%) was similar. The mortality from omphalocele was almost exclusively due to the presence of serious associated congenital anomalies. Two cases of Cantrell's pentalogy and two of cloacal exstrophy were found. The incidence of major malformation with gastroschisis was 6%. Sepsis, inadequate perioperative resuscitation and prolonged gastrointestinal dysfunction were the major causes of death in gastroschisis. Among survivors, the hospital stay was significantly longer in the silon pouch group than in the primary fascial closure group (71.5 vs 31.3 days for gastroschisis, 41 vs 14 days for omphalocele). Advances in surgical technique, neonatal intensive care and ventilatory support have made primary fascial closure a superior approach without jeopardizing the babies' chance for survival. An improved survival rate and increased primary closure rate are the main features in the treatment of abdominal wall defects in the last decade.     

Mast cell degranulation and elastolysis in the early stage of striae distensae

The lesions of nine patients with early striae distensae (SD) during puberty were examined by light and electron microscopy. Specific changes were seen in very early stage SD, and in clinically uninvolved skin 0.5 to 3 cm remote from the edge of the long axis of the SD lesions. Sequential changes of elastolysis accompanied by mast cell degranulation appeared first, followed by an influx of activated macrophages that enveloped fragmented elastic fibers. The relationships among elastic fibers, mast cells, and macrophages seen in the present work suggest their critical roles in the process of SD formation, especially in the early stage. Our results also indicate that the elastic fiber is the primary target of the pathological process, and the abnormalities extend as far as 3 cm beyond the lesion into normal skin.