• Title/Summary/Keyword: AGA

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Purification and Biochemical Characterization of β-agarase Produced by Marine Microorganism Cellulophga sp. J9-3 (해양미생물 Cellulophga sp. J9-3이 생산하는 베타-아가레이즈의 분리 및 생화학적 특성)

  • Kim, Da Som;Kim, Jong-Hee;Chi, Won-Jae
    • Microbiology and Biotechnology Letters
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    • v.49 no.3
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    • pp.329-336
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    • 2021
  • Cellulophga sp. J9-3, is a gram-negative, aerobic marine bacterium belonging to the family Flavobacteriaceae. In addition to cellulose degradability, the J9-3 strain is also capable of hydrolyzing agar in the solid and liquid medium, and the production of agarase in the presence of agarose can be remarkably induced by the bacterium. From the cell culture broth of Cellulophga sp. J9-3, ammonium sulfate precipitation and three kinds of column chromatography were successively performed to purify a specific agarase protein, the AgaJ93. Purified AgaJ93 showed the strongest hydrolyzing activity towards agarose (approximately 22%), and even displayed activity towards starch. AgaJ93 hydrolyzed agarose into neoagarotetraose and neoagarohexaose via various oligosaccharide intermediates, indicating that AgaJ93 is an endo-type β-agarase. AgaJ93 showed maximum activity at a pH of 7.0 and temperature of 35 ℃. Its activity increased by more than six times in the presence of Co2+ ions. The N-terminal sequence of AgaJ93 showed 82% homology with the heat-resistant endo-type β-agarase Aga2 of Cellulophaga sp. W5C. However, the biochemical properties of the two enzymes were different. Therefore, AgaJ93 is expected to be a novel agarose, different from the previously reported β-agarases.

How Our Practice of Histopathology, Especially Tumour Pathology has Changed in the Last Two Decades: Reflections from a Major Referral Center in Pakistan

  • Ahmad, Zubair;Idrees, Romana;Fatima, Saira;Arshad, Huma;Din, Nasir-Ud;Memon, Aisha;Minhas, Khurram;Ahmed, Arsalan;Fatima, Syeda Samia;Arif, Muhammad;Ahmed, Rashida;Haroon, Saroona;Pervez, Shahid;Hassan, Sheema;Kayani, Naila
    • Asian Pacific Journal of Cancer Prevention
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    • v.15 no.9
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    • pp.3829-3849
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    • 2014
  • Continued advances in the field of histo pathology (and cyto pathology) over the past two decades have resulted in dramatic changes in the manner in which these disciplines are now practiced. This is especially true in the setting of a large university hospital where the role of pathologists as clinicians (diagnosticians), undergraduate and postgraduate educators, and researchers has evolved considerably. The world around us has changed significantly during this period bringing about a considerable change in our lifestyles and the way we live. This is the world of the internet and the world-wide web, the world of Google and Wikipedia, of Youtube and Facebook where anyone can obtain any information one desires at the push of a button. The practice of histo (and cyto) pathology has also evolved in line with these changes. For those practicing this discipline in a poor, developing country these changes have been breathtaking. This is an attempt to document these changes as experienced by histo (and cyto) pathologists practicing in the biggest center for Histopathology in Pakistan, a developing country in South Asia with a large (180 million) and ever growing population. The Section of Histopathology, Department of Pathology and Microbiology at the Aga Khan University Hospital (AKUH) in Karachi, Pakistan's largest city has since its inception in the mid-1980s transformed the way histopathology is practiced in Pakistan by incorporating modern methods and rescuing histopathology in Pakistan from the primitive and outdated groove in which it was stuck for decades. It set histopathology in Pakistan firmly on the path of modernity and change which are essential for better patient management and care through accurate and complete diagnosis and more recently prognostic and predictive information as well.

Pharmacokinetics and gastric adhesion of aceglutamide aluminum complex on the combination of antacid in rats

  • Nam, Kweon-Ho;Cho, Jae-Youl;Yoo, Eun-Sook;Han, Sang-Bum;Yu, Young-Hyo;Park, Myung-Hwan;Park, Jeong-Hill
    • Proceedings of the Korean Society of Applied Pharmacology
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    • 1995.04a
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    • pp.97-97
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    • 1995
  • On the combination of antacid, the pharmacokinetics and gastric adhesion of $\^$14/C-aceglutamide aluminum complex($\^$14/C-AGA) were examined in rats. Specially, This study was focused on the drug interaction that the coadministration of antacid may affect the oral absorption and gastric adhesion of aceglutamide aluminum complex(AGA). After the oral administration of $\^$14/C-AGA and antacid to rats, the radioactivity of plasma and urinary recovery was lower than that of $\^$14/C-AGA administered group. Relatively, the cumulative recovery of radioactivity in feces was increased significantly. The comparative bioavailability of $\^$14/C-AGA from the plasma concentration-time curve and urinary recovery was about 60%. in vitro, the effect of antacid in the gastric adhesion of AGA was not significantly different between AGA and AGA/antacid treatment. And it accorded well with the result of in vivo experiment. In conclusion, on the combination of antacid, the oral absorption of AGA was decreased but the gastric adhesion was not affected in respect of drug interaction.

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Pharmacokinetics And Gastric Adhesion Of Aceglutamide Aluminium On The Combination Of Antacid In Rats (흰쥐에서 제산제와 병용투여된 아세글루타미드 알루미늄의 약물동태 및 위장관 부착)

  • 조재열;남권호;유은숙;유영효;박명환;박정일
    • YAKHAK HOEJI
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    • v.39 no.6
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    • pp.577-584
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    • 1995
  • On the combination of antacid, the pharmacokinetics and gastric adhesion of [$^{14}c$]aceglutamide aluminium complex([$^{14}C$]AGA) were examined in rats. Specially, this study was focused on the drug interaction that the co-administration of antacid may affect the oral absorption and gastric adhesion of aceglutamide aluminium complex(AGA). In the study of the oral co-administration of [$^{14}C$] AGA and antacid(aluminium hydroxide and magnesium hydroxide(AM)), the radioactivity of plasma and urinary recovery was lower than that of [$^{14}C$]AGA alone administered group. However, the cumulative recovery of radioactivity in feces was increased significantly. The comparative bioavailability of [$^{14}C$] AGA from the plasma concentration-time curve and urinary recovery was about 60%. In vitro, the effect of antacid on the gastric adhesion of AGA was not significatly different between AGA and AGA/antacid treatment. And it accorded well with the result of in vivo experiment. In conclusion, on the combination of antacid, the oral absorption of AGA was decreased by the gastric adhesion was not affected in respect of drug interaction.

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Gastrointestinal, Liver and Biliary Tract Pathology: A Histopathological and Epidemiological Perspective from Pakistan with a Review of the Literature

  • Ahmad, Zubair;Arshad, Huma;Fatima, Saira;Idrees, Romana;Ud-Din, Nasir;Ahmed, Rashida;Ahmed, Arsalan;Memon, Aisha;Minhas, Khurram;Arif, Muhammad;Fatima, Samia;Haroon, Saroona;Pervez, Shahid;Hasan, Sheema;Kayani, Naila
    • Asian Pacific Journal of Cancer Prevention
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    • v.14 no.11
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    • pp.6997-7005
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    • 2013
  • Aim: To present an epidemiological and histological perspective of diseases of the gastrointestinal tract (including liver and biliary tract) at the Section of Histopathology, Department of Pathology, AKUH, Karachi, Pakistan. Materials and Methods: All consecutive endoscopic biopsies and resections between October 1 and December 31, 2012 were included. Results: A total of 2,323 cases were included. Carcinoma was overwhelmingly the commonest diagnosis on esophageal biopsies (69.1%); chronic helicobacter gastritis (45.6%) followed by adenocarcinoma (23.5%) were the commonest diagnoses on gastric biopsies; adenocarcinoma (27.3%) followed by ulcerative colitis (13.1%) were the commonest diagnoses on colonic biopsies; acute appendicitis (59.1%) was the commonest diagnosis on appendicectomy specimens; chronic viral hepatitis (44.8%) followed by hepatocellular carcinoma (23.4%) were the commonest diagnoses on liver biopsies; chronic cholecystitis was the commonest diagnosis (over 89%) on cholecystectomy specimens. Conclusions: Squamous cell carcinoma comprised 88.8% of esophageal cancers. About 67% were in the lower third and 56.5% were moderately differentiated; mean ages 49.8 years for females and 55.8 years for males; 66% cases were from South West Pakistan. Over 67% patients with gastric adenocarcinoma were males; mean ages 59 and 44 years in males and females respectively, about 74% gastric carcinomas were poorly differentiated; and 62.2% were located in the antropyloric region. About 63% patients with colorectal adenocarcinoma were males; mean ages 46.1 and 50.5 years for males and females respectively; tumor grade was moderately differentiated in 54%; over 80% were located in the left colon. In 21.2% appendicectomies, no acute inflammation was found. Acute appendicitis was most common in young people. Hepatitis C (66.3%) was more common than hepatitis B (33.7%); about 78% cases of hepatocellular carcinoma occurred in males; females comprised 76.7% patients with chronic cholecystitis; and 77.8% patients with gall bladder carcinoma. All resection specimens showed advanced cancers. Most cancers occurred after the age of 50 years.

Commonest Cancers in Pakistan - Findings and Histopathological Perspective from a Premier Surgical Pathology Center in Pakistan

  • Ahmad, Zubair;Idrees, Romana;Fatima, Saira;Uddin, Nasir;Ahmed, Arsalan;Minhas, Khurram;Memon, Aisha;Fatima, Syeda Samia;Arif, Muhammad;Hasan, Sheema;Ahmed, Rashida;Pervez, Shahid;Kayani, Naila
    • Asian Pacific Journal of Cancer Prevention
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    • v.17 no.3
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    • pp.1061-1075
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    • 2016
  • Context: There are no recent authoritative data about incidence and prevalence of various types of cancers in Pakistan. Aim: To determine the frequency of malignant tumors seen in our practice and provide a foundation for building a comprehensive cancer care strategy. Materials and Methods: 10,000 successive cases of solid malignant tumors reported in 2014 were included. All cases had formalin fixed, paraffin embedded specimens available and diagnosis was based on histological examination of H&E stained slides plus ancillary studies at the Section of Histopathology, Department of Pathology and Laboratory Medicine, Aga Khan University Hospital, Karachi. The latest WHO classifications were used along with the latest CAP protocols for reporting and the most updated TNM staging. Results: There were 9,492 (94.9%) primary tumors while 508 (5.1%) were metastatic. Some 5,153 (51.5%) were diagnosed in females and 4,847 (48.5%) in males. The commonest malignant tumors in females were breast (32%), esophagus (7%), lymphomas (6.8%), oral cavity (6.7%) and ovary (4.8%), while in males they were oral cavity (13.9%), lymphomas (12.8%), colorectum (7.9%), stomach (6.9%) and esophagus (6.6%). Malignant tumors were most common in the 5th, 6th and 7th decades. About 8% were seen under 20 years of age. Conclusions: Oral cavity and gastrointestinal cancers continue to be extremely common in both genders. Breast and esophageal cancers are prevalent in females. Lung and prostate cancer are less common than in the west. Ovarian cancer was very common but cervix cancer was less so.

Overdentures using newly designed metal ball attachment containing predetermined gap with stress breakers (일정한 간극으로 새롭게 고안된 완압형 볼 어태치먼트를 이용한 피개의치 수복)

  • Yoo, Jin-Joo;Kim, Man-Yong;Yoon, Joon-Ho
    • The Journal of Korean Academy of Prosthodontics
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    • v.55 no.3
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    • pp.311-318
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    • 2017
  • Several types of attachments have been used for implant supported and/or retained overdentures. Locator is one of the stud type attachments and it has been generally used. However, the colored matrix is resilient and vulnerable to wear, so frequent post-insertion maintenance is needed. To solve this problem, it is necessary to introduce innovative attachment system. Overdentures using Air Gap attachment (AGA) has improved masticatory function and facial esthetics. AGA is made of metal, so it could be more resistant to wear or friction than the other resilient attachments. Nevertheless, AGA plays a role in stress breakers because it allows movement during denture movement with predetermined gap. In addition, both pre-existing implants and natural teeth were successfully used for connection of AGA. AGA could replace other unsplinted type of attachments. Overdentures using AGA could provide satisfactory result in terms of function, esthetics and retention. However, long term follow up is needed.

Isolation and Characterization of an Eosinophilic GH 16 β-Agarase (AgaDL6) from an Agar-Degrading Marine Bacterium Flammeovirga sp. HQM9

  • Liu, Yan;Tian, Xiaoxu;Peng, Chao;Du, Zongjun
    • Journal of Microbiology and Biotechnology
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    • v.29 no.2
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    • pp.235-243
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    • 2019
  • A special eosinophilic agarase exo-type ${\beta}$-agarase gene, AgaDL6, was cloned from a marine agar-degrading bacterium, Flammeovirga sp. HQM9. The gene comprised 1,383-bp nucleotides encoding a putative agarase AgaDL6 of 461 amino acids with a calculated molecular mass of 52.8 kDa. Sequence analysis revealed a ${\beta}$-agarase domain that belongs to the glycoside hydrolase family (GH) 16 and a carbohydrate-binding module (CBM_4_9) unique to agarases. AgaDL6 was heterologously expressed in Escherichia coli BL21 (DE3). Enzyme activity analysis of the purified protein showed that the optimal temperature and pH of AgaDL6 were $50^{\circ}C$ and 3.0, respectively. AgaDL6 showed thermal stability by retaining more than 98% of activity after incubation for 2 h at $50^{\circ}C$, a feature quite different from other agarases. AgaDL6 also exhibited outstanding acid stability, retaining 100% of activity after incubation for 24 h at pH 2.0 to 5.0, a property distinct from other agarases. This is the first agarase characterized to have such high acid stability. In addition, we observed no obvious stimulation or inhibition of AgaDL6 in the presence of various metal ions and denaturants. AgaDL6 is an exo-type ${\beta}$-1,4 agarase that cleaved agarose into neoagarotetraose and neoagarohexaose as the final products. These characteristics make AgaDL6 a potentially valuable enzyme in the cosmetic, food, and pharmaceutical industries.

Glucose Transport through N-Acetylgalactosamine Phosphotransferase System in Escherichia coli C Strain

  • Kim, Hyun Ju;Jeong, Haeyoung;Lee, Sang Jun
    • Journal of Microbiology and Biotechnology
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    • v.32 no.8
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    • pp.1047-1053
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    • 2022
  • When ptsG, a glucose-specific phosphotransferase system (PTS) component, is deleted in Escherichia coli, growth can be severely poor because of the lack of efficient glucose transport. We discovered a new PTS transport system that could transport glucose through the growth-coupled experimental evolution of ptsG-deficient E. coli C strain under anaerobic conditions. Genome sequencing revealed mutations in agaR, which encodes a repressor of N-acetylgalactosamine (Aga) PTS expression in evolved progeny strains. RT-qPCR analysis showed that the expression of Aga PTS gene increased because of the loss-of-function of agaR. We confirmed the efficient Aga PTS-mediated glucose uptake by genetic complementation and anaerobic fermentation. We discussed the discovery of new glucose transporter in terms of different genetic backgrounds of E. coli strains, and the relationship between the pattern of mixed-acids fermentation and glucose transport rate.