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Biomedical subjects

A K Attri

Publications and source records attributed to A K Attri.

At least 19 recordsLinked to original sources
PubMed2006

Bowel injury following induced abortion.

OBJECTIVE: Bowel injury is an uncommonly reported yet serious complication of induced abortion, which is often performed illegally by persons without any medical training in developing countries. A sudden increase in cases prompted the authors to analyze this problem. METHOD: A retrospective review was done of 11 cases of bowel injury following induced abortion seen over 2 years at Government Medical College and Hospital, Chandigarh, India. RESULTS: Young, married women of low socioeconomic status with a strong preference for male children were the predominant recipients of induced abortion in India. The terminal ileum and pelvic colon were the most commonly injured portions of the bowel owing to their anatomic locations. CONCLUSION: Preoperative resuscitation, then resection with exteriorization of bowel and thorough peritoneal lavage, is the treatment for bowel injury incurred during induced abortion when the patient presents late.

Abortion, Illegal↗
PubMed2004

Traumatic abdominal wall hernia.

A traumatic abdominal wall hernia (TAWH) is a rare type of hernia, which follows blunt trauma to the abdomen, where disruption of the musculature and fascia occurs, with the overlying skin remaining intact. The case of a sixty five year old female that developed a TAWH, following the collapse of the roof of her house, is reported. She underwent a laparotomy for suspected liver injury, followed by repair of the hernia using a fascia lata graft taken from the thigh. The etiology, pathogenesis and management of this rare hernia are discussed.

Abdominal Wall↗
PubMed2003

Incisional hernia from iliac bone grafting site--a report of two cases.

Incisional hernia is a fairly common problem in India, although there is a paucity of data from the region. The commonly implicated operations in the aetiology of incisional hernia in our setup are lower segment cesarean sections and surgery for peritonitis. Incisional hernia following iliac bone grafting is rare, despite the frequency of performance of the procedure. Two patients with incisional hernia arising from the donor site of iliac bone grafting were seen in our department over the last year. They underwent mesh hernioplasty using polypropylene mesh that was placed as an onlay. Both the patients are presently well on follow-up, with no recurrence of the hernia. Mesh hernioplasty of hernia following iliac bone grafting gives good results and may be considered the method of choice of repair of this uncommon type of hernia.

Aged↗
PubMed2002

Laparoscopic cholecystectomy: an Indian experience of 1233 cases.

BACKGROUND: Laparoscopic cholecystectomy (LC) is a well-established procedure for symptomatic cholelithiasis in India, but there are few data available regarding the procedure and its related complications. PATIENTS AND METHODS: This paper represents a retrospective review of 1233 patients who underwent LC at Government Medical College and Hospital, Chandigarh, India, over 4 years (1997-2000). The case files of all these patients were analyzed for patient particulars, intraoperative findings, reason for any open conversion, postoperative stay, and mortality. RESULTS: The overall conversion rate was 7.06% (87 patients). The commonest cause of conversion was a frozen Calot's triangle (52 patients), followed by injury to the common bile duct (8 patients). The average postoperative stay in successful LC was 1.32 days. The overall mortality rate was 0.16% (2 deaths). The quality of life after LC was good to excellent in more than 90% of patients. CONCLUSIONS: Despite multiple hands in training, the complication rates of LC are within acceptable limits. The overall conversion rate has risen because of the increase in elective conversions, but the incidence of complications has come down because of a "no hesitation" policy in converting. In spite of multiple operators, LC is the procedure of choice for symptomatic cholelithiasis at our hospital.

Adolescent↗
PubMed2001

Osteosarcoma of the bladder--a case report.

A 25-year old man with hematuria had a polypoid tumor of the urinary bladder which was diagnosed as transitional cell carcinoma (TCC) on transurethral resection with partial cystectomy. One year following post-operative radiotherapy, he had to undergo surgery for intestinal perforation. On laparotomy the recurrent tumor had involved pelvic organs and sigmoid colon. It now showed predominantly osteogenic sarcoma on histopathologic examination. The case is reported in view of rarity of primary osteogenic sarcoma in the urinary bladder.

Adult↗
PubMed1995

Conversion of loop colostomy to end colostomy: is dismantling necessary?

Twelve patients who had previously undergone preliminary pelvic loop colostomy were treated by conversion of loop colostomy to end colostomy by alternative technique ie without dismantling of loop and conversion to end stoma. The results of this technique were compared with those of conventional procedure which was performed in ten patients. The new technique results in a 'mature' end colostomy in situ with little pain at the stoma site, no risk of retraction and lower risk of peristomal infection. We therefore recommend this procedure for all patients needing such conversion.

Colostomy↗
PubMed1991

The formation of actin oligomers studied by analytical ultracentrifugation.

The small oligomers formed from Mg-G-actin under favorable conditions were studied by sedimentation velocity ultracentrifugation. The critical concentration of actin at pH 7.8 in the presence of 100 microM MgCl2 and 200 microM ATP was 12.5 +/- 2.8 microM. Under these conditions, about 15% of 7.5 microM Mg-actin was converted to oligomers of subunit size four to eight in 5 h at 20 degrees C. In 100 microM MgCl2 and no free ATP, the critical concentration was about 6.5 microM, and about 22% of 7.5 microM Mg-actin was converted to dimers in 80 min. There were no detectable higher oligomers or F-actin present in either case. As determined by the analysis of ATP hydrolysis, most, if not all, of the oligomer subunits contained ATP. When 28.5 microM actin was polymerized to steady state in 100 microM MgCl2 and 200 microM ATP, about 50% of the actin was present as F-actin, consistent with the critical concentration (approximately 12.5 microM), about 50% as oligomers as large as seven subunits, and only about 5% as monomers. When solutions containing oligomers were diluted the oligomers dissociated. Alternatively, when the MgCl2 concentration was raised to 1 mM, the solutions containing oligomers polymerized more rapidly than monomeric Mg-G-actin and to the same final steady state. These data are entirely consistent with the condensation-elongation model for helical polymerization proposed by Oosawa and Kasai (Oosawa, F., and Kasai, M. (1962) J. Mol. Biol. 4, 10-21) according to which, under certain conditions, substantial amounts of short linear and helical oligomers should be formed below the critical concentration and linear oligomers should coexist with monomers and F-actin at steady state.

Actins↗
PubMed1990

Regulation of the actin-activated ATPase activity of Acanthamoeba myosin II by copolymerization with phosphorylated and dephosphorylated peptides derived from the carboxyl-terminal end of the heavy chain.

Myosin II from Acanthamoeba castellanii is a conventional myosin composed of two heavy chains and two pairs of light chains. The amino-terminal approximately 90 kDa of each heavy chain form a globular head that contains the ATPase site and an ATP-sensitive actin-binding site. The carboxyl-terminal approximately 80 kDa of both heavy chains interact to form a coiled coil, helical rod (through which the molecules self-associate into bipolar filaments) ending in a short nonhelical tailpiece. Phosphorylation of 3 serine residues at the tip of the tail (at positions 11, 16, and 21 from the carboxyl terminus) inactivates the actin-activated Mg2(+)-ATPase activity of myosin II filaments. Previous work had indicated that the activity of each myosin II molecule in a filament reflects the global state of phosphorylation of the filament rather than the phosphorylation state of the molecule itself. We have now purified the approximately 28-kDa carboxyl-terminal region of the heavy chain lacking the last two phosphorylation sites, and we have shown that this peptide copolymerizes with and regulates the actin-activated Mg2(+)-ATPase activities of native dephosphorylated and phosphorylated myosin II. It can be concluded from these studies that the biologically relevant enzymatic activity of myosin II is regulated by a phosphorylation-dependent conformational change in the myosin filaments.

Acanthamoeba↗
PubMed1987

Simultaneous determination of the individual concentration gradients of two solute species in a centrifuged mixture: application to analytical ultracentrifugation.

A procedure for determining the absolute activity of 14C-labeled and 3H-labeled solutes in a mixture from the measured counts per minute in two scintillation energy windows is described. It is shown that the method described here provides a substantially more accurate determination of 3H activity in the presence of a larger 14C activity, and a more accurate determination of 14C activity in the presence of a larger 3H activity, than does the standard dual label analysis implemented in a Beckman LS 3801 scintillation counter. The new dual label procedure is combined with the automated fractionation procedure of Attri and Minton [(1986) Anal. Biochem. 152, 319-328] to permit the gradients of each of two differently radiolabeled solute species in a mixture to be individually determined following centrifugation. It is shown that the sedimentation coefficients of each of two differently labeled noninteracting proteins in a mixture may be readily determined in a sedimentation velocity experiment, and that the molecular weights of each of two such proteins in a mixture may be readily determined in a sedimentation equilibrium experiment.

Carbon Radioisotopes↗
PubMed1986

An automated method for determining buoyant density of nucleic acids using a preparative ultracentrifuge.

We present a technique for analytical buoyant density sedimentation of nucleic acids which is performed in a preparative ultracentrifuge, in contrast to an analytical ultracentrifuge. Following centrifugation in a preparative rotor, small cylindrical quartz tubes are optically scanned; upon completion of the scan the data are processed immediately by a microcomputer and the buoyant density of the nucleic acid is calculated. Experimental data are presented employing several different deoxyribonucleic acids banded in neutral and alkaline cesium sulfate. Results are independent of rotor speed, location of bands within the gradient, and loading density of the cesium sulfate solution. Derived buoyant density values agree within 0.5% of previously published values.

Centrifugation, Density Gradient↗
PubMed1986

UV-induced interstrand cross-linking of d(GT)n.d(CA)n is facilitated by a structural transition.

Photochemical alterations following ultraviolet irradiation of the alternating copolymer d(GT)n.d(CA)n were studied. We found that in solution conditions which produced circular dichroism spectra compatible with B-form or A-form DNA, no interstrand cross-linking or photoproduct formation could be demonstrated. Zimmer et al. (Zimmer, C., Tymen, S., Marck, C., and Guschlbaumer, W. (1982) Nucleic Acids Res. 10, 1081-1091) and Vorlickova et al. (Vorlickova, M., Kypr, J., Sotkrova, S., Sponar, J. (1982) Nucleic Acids Res. 10, 1071-1080) have reported a number of solution conditions which produce a structural transition of this polymer characterized by a negative deviation of the circular dichroism spectrum in the region of 280 nm. The nature of this transition has not yet been elucidated. Following ultraviolet irradiation of d(GT)n.d(CA)n under two conditions which produce this transition (manganese solution or ethanol plus trace salts solution) we found ultraviolet dose-dependent interstrand cross-linking as well as dose-dependent formation of thymine-containing photoproduct. Interstrand cross-linking is demonstrated by two criteria: increase in polymer size as detected by alkaline agarose gel electrophoresis, and generation of intermediate density material in alkaline cesium sulfate isopycnic gradients. The thymine-containing photo-product was demonstrated by thin layer chromatography of acid hydrolysates of the polymer. The photo-product is at least partially photoreversible. These findings suggest that the geometry of the alternative conformation is such that pyrimidines from different strands are closely approximated, allowing for photodimerization.

Centrifugation, Density Gradient↗
PubMed1986

Technique and apparatus for automated fractionation of the contents of small centrifuge tubes: application to analytical ultracentrifugation.

An automated method is described for dividing the contents of small cylindrical centrifuge tubes into fractions deriving from laminae of solution as thin as 0.1 mm in the direction of the cylindrical axis. Experimental data are presented to demonstrate that fractions as small as 1 microliter may be prepared with a standard deviation of less than 3% in volume delivery and that negligible mixing occurs between the contents of adjacent fractions during the fractionation procedure. The method has been used to quantitate the gradients of a variety of radiolabeled proteins formed in sedimentation velocity and sedimentation equilibrium experiments. Sedimentation coefficients and molecular weights calculated from the gradients obtained agree well with literature values and with values obtained by optically scanning the centrifuge tubes (A.K. Attri and A.P. Minton, 1983, Anal. Biochem. 133, 142-152; 1984, Anal. Biochem. 136, 407-415). The present technique combines a spatial resolution equal to that of optical methods of gradient measurement with a sensitivity which may be several orders of magnitude greater, depending upon the specific activity of labeled solute.

Animals↗
PubMed1986

Lap computers in the laboratory.

The acquisition of data from laboratory instruments and the automatic control of experimental apparatus is facilitated by the use of small, inexpensive battery-powered microcomputers ('lap computers'). Useful capabilities and features of currently available lap computers are summarized. A general strategy for data acquisition from laboratory instruments is outlined, and three illustrative examples of particular applications of lap computers in data acquisition and experimental control are described.

Electronic Data Processing↗
PubMed1984

An automated method for determination of the sedimentation coefficient of macromolecules using a preparative centrifuge.

Following centrifugation in a preparative ultracentrifuge at relatively high speeds for 1-3 h, quartz tubes containing approximately 150 microliter of macromolecular solution are optically scanned using an apparatus and method previously described (Attri, A. K., and Minton A. P. (1983) Anal. Biochem. 133, 142-152). The resulting data are processed by microcomputer immediately upon completion of scanning to yield the sedimentation coefficient of the solute. Calculated values agree to within a few percent with those found in the literature and with the results of control experiments carried out using an analytical ultracentrifuge.

Chymotrypsinogen↗
PubMed1983

An automated method for determination of the molecular weight of macromolecules via sedimentation equilibrium in a preparative ultracentrifuge.

An automated method for quantitating the concentration gradient of a macromolecule brought to sedimentation equilibrium in a preparative ultracentrifuge is described. Between 30 and 80 microliter of macromolecular solution are spun in a combination centrifuge tube and optical cell fabricated from quartz. Immediately following the conclusion of centrifugation the tube is optically scanned along its length using a spectrophotometer sample cell modified for this purpose. Successive scans of the same tube containing first solution and then solvent permit the differential absorbance due to macromolecule to be measured precisely as a function of position within the centrifuge tube, and hence the radial position within the rotor. Molecular weights calculated from data so obtained from 32 centrifugations of eight proteins ranging in Mr from 12K to 340K using either swinging-bucket or fixed-angle rotors agree with previously published values with a standard deviation of 5%.

Autoanalysis↗
PubMed1982

Spectrophotometric observations on the changes in the Y-peak of actinomycin D complexed to DNA on gamma-irradiation.

An understanding of the pi-pi * transitions of the Y-peak of the DNA bound to actinomycin D, in the presence and absence of gamma-irradiation has been attempted. It was seen that in the bound DNA the presence of the Y-peak, without irradiation was mainly due to the pi-pi * transitions associated with the DNA bases. The Y-peak was found to be more sensitive to the binding of the drug than the X-peak. After gamma-irradiation the Y-peak characteristics of the complexed DNA were different from those of the X-peak. From these studies it has been concluded that the electronic transitions (pi-pi *) of the DNA, in the far U.V., can be divided into three distinct groups: (a) Electronic transitions which are only seen at the Y-peak, (b) Transitions common both to the X and Y-peaks, and (c) Transitions which are only seen at the X-peak. This explains the difference in the behaviour of the Y- and X-peaks of the DNA due to the binding of Act.D and gamma-irradiation.

Animals↗
PubMed1981

Dependence of gamma-irradiated Y-peak and melting of DNA on concentration and ionic environment.

Y-peak is found to be a function of ionic strength and concentrations of DNA. The Y-peak reveals close dynamic interaction between DNA and solvent system. Electronic transitions responsible for Y-peak are not the same transitions that are responsible for X-peak. Y-peak's electronic transitions are indicative of charge transfer complex formation between DNA and solvent system. gamma-Irradiation induces hyperchromicity due to strand separation at lower doses. A-T base pairs are first to undergo coiled state as shown by delta Tm spread. Strand chopping and saturation of double bonds of the exposed bases by free radicals (H degrees and OH degrees) give rise to hypochromic regions at X-peak. Rise in ionic strength and the concentration of DNA has protective effect against gamma-damage. Y-peak is found to be a function of solvent, whereas, X-peak is independent of solvent nature.

Animals↗