Studies on carbohydrate moieties of the glycoprotein, glucoamylase II of Aspergillus niger: nature of carbohydrate-peptide linkage and structure of oligosaccharides

Electrophoretically homogeneous type 1 (GP-C1 and GP-C2), type 2 (GP-C3a and GP-C3b,) and type 3 (GP-D1, and GP-D2) glycopeptides from Aspergillus niger glucoamylase II (Manjunath and Raghavendra Rao, preceding paper) were separately treated with alkaline borohydride. The (β-eliminated oligosaccharides were subjected to single and sequential digestion with specific glycosidases and the products analysed by gas liquid chromatography. The studies revealed that carbohydrate moieties were present as mannose, Man-Man-, and trisaccharide structures, namely, (a) GIc-Man-Man-, (b) Gal-Man-Man, (c) Man-Man-Man-, (d) GlcNAc-Man-Man-, and (e) Xyl-Man-Man. None of the glycopeptides contained all the trisaccharide structures (a) to (e). Type 1 glycopeptide contained structures (a), (b) and (c); type 2, (a) and (d) and type 3, (a), (b) and (e). The number of carbohydrate units (mono-, di-and trisaccharides) present in the major glycopeptides was determined and tentative structures for the glycopeptides proposed. Carbohydrate units appeared to occur in clusters of 4 to 7 in each glycopeptide, a structure unique to the carbohydrate moiety in Aspergillus niger glucoamylase. Based on carbohydrate analysis and yields of glycopeptide, the number of units of each type of glycopeptide present in glucoamylase II was tentatively calculated to give two of type Man:Glc:Gal = 12-15:l:l, one of type Man:Glc:GlcN = 10-l1:1:2 and one of type Man :GIc :Gal:Xyl = 4-8:0.1:0.5-0.8:0.3-1 glycopeptides

Comparative studies on glucoamylases from three fungal sources

Five commercial preparations of glucoamylases (three from Aspergillus niger, one each from Aspergillus foetidus and Aspergillus candidus) were purified by ultrafiltration, Sepharose-gel filtration and DEAE-sephadex chromatography. Two forms of the enzyme, namely glucoamylase I and glucoamylase II were obtained from the fungi except from one strain of A. Niger. All the enzymes appeared homogeneous by electrophoresis and ultracentrifugation. The specific activities varied between 85 and 142 units. The pH and temperature optima were between 4 and 5, and 60°C respectively. The molecular weight as determined by the sodium dodecyl sulphate-polyacrylamide gel electrophoresis ranged from 75,000 to 79,000 for glucoamylase I and 60,000 to 72,000 for glucoamylase II. Only A. niger glucoamylases contained phenylalanine at the N-terminal end. The amino acid composition of the enzymes was generally similar. However, A. niger and A. foetidus glucoamylases, in contrast to A. candidus enzymes, contained greater percentage of acidic than of basic amino acids. The enzymes contained 15 to 30% carbohydrate and 49 to 57 residues of monosaccharides per mol. A. niger enzymes contained mannose, glucose, galactose, xylose and glucosamine but the A. candidus enzyme lacked xylose and glucose and only xylose was absent in A, foetidus enzymes. Majority of the carbohydrate moieties were O-glycosidically linked through mannose to the hydroxyl groups of seline and threonine of the polypeptide chain

FORMULATION AND EVALUATION OF VALSARTAN FAST DISINTEGRATING TABLETS BY VACUUM DRYING TECHNIQUE

ABSTRACTObjective: The main objective present research work an attempt has been made to prepare fast dissolving tablets of Valsartan by using vacuumdrying technique. Camphor, Urea and Menthol are used as a sublimating agent. Valsartan is an oral antihypertensive agent, with problems of variablebioavailability and bioequivalence related to its poor water solubility. Valsartan is an angiotensin II type 1 receptor antagonist indicated in thetreatment of hypertension. Methods: The prepared tablets Valsartan fast dissolving tablets were evaluated for various parameters like weight variation, hardness, friability,disintegration time, drug content, water absorption ratio, wetting time, in- vitro drug release, FTIR, DSC studies and short term stability studies. Theblend was examined for the pre-compressional and post-compressional parameter. Results and Discussions: The values of pre-compression parameters evaluated were within prescribed limits and indicated good free flowingproperty. All the post-compressional parameter are evaluated were prescribed limits and results were within IP acceptable limits. Based on the invitrodisintegrationtime and dissolution studies formulationsSC2 andSC3werefoundtobe promisingandshowedadisintegrationtime of 24secand16 secrespectively.FormulationSC3 containingcamphor showedhighestdrug release99.4% within10 min.IR spectralanalysisandDSC studyshowedthattherewasno drug interactionwith formulationadditivesofthetablet asthereis novariationand shift inthe position ofcharacteristicabsorptionbands it canbejustifiedthereis no interactionbetweendrug and polymer.Short termstability studieson the formulationsindicatedthatthereareno significant change in hardness,friability,drug contentand in-vitrodrug release(p<0.05). Conclusion: The results concluded that fast dissolving tablets of Valsartan showing enhanced dissolution may lead to improved bioavailabilityand effective therapy by using sublimation method.Keywords: Fast dissolving tablet, Valsartan, Crospovidone, Camphor, Urea, Disintegration time

Studies on carbohydrate moieties of Aspergillus niger glucoamylase. II: Isolation, purification and characterization of glycopeptides

Six glycopeptide fractions namely GP-C1, GP-C2, GP-C3a, GP-C3b, GP-D, and GP-D2 were isolated after exhaustive digestion of glucoamylase II (Glucozyme) from Aspergillus niger with pronase. They were purified using gel-filtration. high-voltage paper electrophoresis and ion-exchange chromatography on Dowex-50 and Dowex-1. They appeared homogeneous on electrophoresis under different conditions of pHs. The molecular weights ranged from 1600 and 4000 for these glycopeptides. Ally of them contained serine at the N-terminal end. Serine and threonine were the major amino acids with glycine, alanine, proline and tryosine present as minor constituents. Carbohydrate analysis revealed the presence of different sugars. Based on this, the glycopeptides were grouped into three types: (1) GP-C1 and GP-C2 containing mannose, glucose and galactose; (2) GP-C3a, and GP-C3b,containing mannose glucose and glucosamine; and (3) GP-D1 and GP-D2, containing mannose. glucose, galactose and xylose. Most sugar constituents in each glycopeptide occured in non-integral ratios implying a microheterogeneity of the carbohydrate moiety in Aspergillus niger glucoamylase II

Endovascular retrieval of difficult to remove port-a-caths

Long dwelling central venous lines develop intravenous adhesions or a calcified fibrous sheath causing difficulties in removal. Although such cases are rare, a few cases of endovascular retrieval have been reported in pediatric literature. We report our experience with 6 cases in children with port-a-caths. Transfemoral snare technique was effective in all but 1 patient. The mean age of the in dwelling port-a-caths was 5 years. One patient whose catheter could not be removed has developed no complications after a follow-up of 5 years. Review of literature suggests that while endovascular retrieval is not without risks, leaving a central line in situ has no major disadvantages. Heroic measures to remove such lines should be pursued only when absolutely necessary as in the case of an infected line

A comparative study of laser posterior cordotomy and vocal cord lateralization

AbstractIntroductionThe treatment of bilateral vocal cord paralysis continues to be a challenge to the otolaryngologist, head and neck surgeon even today. Numerous surgical procedures have been proposed to improve the patient’s airway insufficiency without leaving the patient with a breathy, weak voice or an incompetent larynx. In this study we compared the outcome of laser posterior cordotomy and vocal cord lateralization in a group of bilateral abductor palsy patients.MethodRetrospective as well as a prospective study of 25 patients was carried out. The total of 25 patients was divided into 2 groups, group 1 consisted of 15 patients who underwent vocal cord lateralization with SUTUPAK suture and group 2 consisted of 10 patients who underwent laser assisted posterior partial cordotomy.ResultsThyroidectomy was the commonest cause for bilateral vocal fold paralysis i.e. 80% (20) of cases. Patients who underwent laser posterior cordotomy had 100% successful decannulation rate as compared to 92.8% for vocal cord lateralization patients. Comparison between pre and post operative voice assessment data by WILCOXON SIGNED RANKS test revealed that excepting the parameter of fluctuations/s in F0, all other parameters were statistically not significant.ConclusionLaser cordotomy is a superior, reliable and viable alternative to the other lateralization procedures for bilateral vocal fold paralysis

Estudio de la Lidocaína al 0,5% y en Combinación de Lidocaína al 0,25% con Fentanilo y Vecuronio en Anestesia Regional Intravenosa para Cirugías de Miembros Superiores

ResumenJustificativa y objetivosLa anestesia regional intravenosa (ARIV) para cirugías de miembros superiores con la tradicional dosis alta de lidocaína, puede conllevar a efectos colaterales que amenazan la vida. Para evitar esos efectos colaterales potencialmente amenazadores, muchas técnicas modificadas de ARIV fueron experimentadas con el uso de una dosis baja de lidocaína, relajante muscular y opioide.Materiales y métodosEl presente estudio se hizo con 60 pacientes no medicados previamente, con clasificación ASA 1-2, para comparar las características sensoriales y motoras, los parámetros cardiorrespiratorios y los efectos colaterales durante el período intraoperatorio y de deflación pos torniquete, entre los pacientes que recibieron 40mL de lidocaína al 0,5% sola (n = 30) y los que recibieron una combinación de 40mL de lidocaína al 0,25% con 0,05mg de fentanilo y 0,5mg de vecuronio (n = 30) en ARIV para cirugías ortopédicas de miembros superiores. Los resultados se analizaron usando el teste t de Student pareado para identificar la significancia estadística. Resultado: La diferencia entre los dos grupos con relación al tiempo promedio de inicio y completo bloqueo sensitivo y motor, fue estadísticamente significativo. Sin embargo, hubo un completo bloqueo sensitivo y motor en ambos grupos 15 minutos después de la inyección de la solución anestésica. Conclusiones: Aunque la pequeña demora observada al inicio y durante la obtención completa de los bloqueos sensitivo y motor, teóricamente pueda atrasar el inicio de la operación entre 10 y 15 minutos, clínicamente ese tiempo se gastaría en la preparación del campo quirúrgico. Por tanto, esa combinación puede ser usada con seguridad y eficacia en la anestesia regional intravenosa para las cirugías ortopédicas de miembros superiores con menor posibilidad de toxicidad anestésica local

DESIGN AND DEVELOPMENT OF ORAL SUSTAINED RELEASE MATRIX TABLETS OF DIDANOSINE

Objectives: In present study, an attempt was made to design sustained-release tablets containing Didanosine using natural gums like Xanthan gum, Guar gum and Karaya gum. Methods: The sustained-release tablets containing Didanosine prepared by using natural gums by wet granulation method. Influence of natural polymer on Didanosine was studied. The prepared tablets were selected for DSC and FTIR studies.Results and Discussions: The tablets were selected for DSC and FTIR studies did not show any chemical interaction between drug and polymer. The prepared formulations were evaluated for Hardness, Thickness, Friability, Weight variation, drug content estimation, Swelling index, in-vitro drug release are within the acceptable standard. In-vitro release profile was check for 8 hrs to evaluate the SR matrix tablet of Didanosine. The optimized tablets were carried out according to ICH guidelines at 40 ± 2º C/ 75 ± 5percent RH for three months. All the prepared tablets were stable at room temperature. The values of pre-compression parameters of prepared granules were evaluated the results were within prescribed limits and indicated good free flowing property. The prepared tablets were subjected to all the quality control tests they were within the official pharmacopoeial limits. Friability is less than 1percent, indicated that tablets had a good mechanical resistance. Weight variation test revealed that the tablets were within the range of pharmacopoeial limit. Thickness, hardness and drug content were within the range of pharmacopoeial limit. The evaluation parameters were within acceptable range for all the formulations. The in-vitro release of Didanosine was conducted for 8 hrs. The optimized formulations WGX3, WGG5 and WGK9 sustained the release up to 8hr. Hence Didanosine along with Xanthan gum, Guar gum and Karaya Gum could be used to prepared sustained released matrix tablets. The in-vitro release obeyed zero order kinetics with mechanism of release was erosion followed by non-fickian diffusion.Conclusion: Among all the formulations WGK9 is the best shows excellent release around 99percent after 8 hrs. The prepared matrix tablets of Didanosine were stable. So, it may be concluded that sustained release matrix tablets would improve the patient compliance and bioavailability may be improved. Keywords:  Didanosine, Xanthan gum, Guar gum and Karaya gum

The Sheared Central Venous Catheter?

A fractured central venous catheter (CVC) with embolization of the distal fragment may lead to life-threatening complications. We had inserted a right subclavian CVC in a 68-year-old female which upon a follow-up chest X-ray appeared to have been sheared. A guidewire was inserted through the CVC until the J-tip was just beyond the tip of the CVC which were then withdrawn as a single assembly. We suspected that the tip of the guidewire might have been entrapped in the opening of the middle port, which upon withdrawal of the guidewire could have led to CVC folding upon itself and shearing