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N Pokala

Publications and source records attributed to N Pokala.

8 recordsLinked to original sources
PubMed2005

Laparoscopic vs open total colectomy: a case-matched comparative study.

BACKGROUND: Open total colectomy and ileorectal anastomosis (OTC) is a major colorectal procedure which would preclude laparoscopy in many centers because of technical difficulty and the fact that laparoscopic total colectomy (LTC) takes much longer than standard laparoscopic proctosigmoidectomy (LPS). This study compares OTC with LTC and LPS. METHODS: In this study, 34 LTC patients (May 1999 to August 2003) were matched for age, diagnosis, operative period, and procedure with patients undergoing OTC. Patients with a previous major laparotomy were excluded from the open group. Groups were compared for gender, American Society of Anesthesiology (ASA) classification, operating time, estimated blood loss, length of hospital stay (LOS), complications including readmissions, and costs. The LPS cases were picked randomly from the laparoscopic database (every eighth patient), and the OT and LOS were noted. RESULTS: The LTC and OTC groups were matched for age (mean, 31 vs 34 years; p = 0.2), sex (14 vs 13 females; p = 0.8), ASA (8/23/3/0 vs 8/22/4/0, class 1/2/3/4). The body mass index was higher in the open group (23.8 vs 27.9; p = 0.04). The operating time was significantly longer (187 vs 126 min; p = 0.0001) and the median LOS shorter in the LTC group (3 days [IQR, 2.5-5 days] vs 6 days [IQR 4-8 days]; p = 0.0001). The estimated blood loss was significantly less in the LTC group (168 [50-700] ml) vs 238 [50-800] ml); p = 0.001, but there was no significant difference in the complication (26.5% vs 38.2%; p = 0.4) readmission (11.8% vs 14.7%; p = 1.0), reoperative rates (8.8% vs 11.8%; p = 1.0), or direct costs ($4,578 vs $4,562; p = 0.3). One LTC patient died expired on postoperative day 2 of a cardiac event. Four patients (11.8%) required conversion for obesity (n = 2), adhesions (n = 1), or intraoperative hemorrhage (n = 1). The operating times were 36 min longer in the LTC group than in the LPS group (151 vs 187 min; p = 0.02), but there was no significant difference in the LOS. (3 vs 3 days, p = 0.2). CONCLUSIONS: The findings show that LTC provides a significant decrease in the LOS over OTC, with increased operating time, but without any change in other parameters. A laparoscopic approach to subtotal colectomy is recommended for suitable patients when an experienced team is available.

Adult↗
PubMed2004

Elective laparoscopic surgery for benign internal enteric fistulas: a review of 43 cases.

BACKGROUND: Laparoscopic surgery has been applied to the management of various colorectal conditions, with shorter recovery periods than reported for open surgery. This study reviewed the feasibility and outcome of laparoscopic surgery for benign internal enteric fistulas. METHODS: All the patients undergoing laparoscopic surgery for colovesical, colovaginal, enterovesical, and enterocolic fistulas caused by diverticulitis or Crohn's disease from 1995 to 2003 were identified from the prospective laparoscopic surgery database and retrospectively analyzed. Crohn's ileo-ileal fistulas were excluded from the study because these are generally resected more simply en bloc with the terminal ileum. RESULTS: This study enrolled 43 patients (23 men and 20 women) with median age of 43 years, a mean body mass index of 24.5, and in American Society of Anesthesiology (ASA) distribution of 3/33/8/0 (class 1/2/3/4). The diagnosis was diverticular for 24 patients and Crohn's disease for 19 patients. The mean operative time was 163 +/- 80 min (155 in completed and 180 in converted cases), and the mean length of hospital stay was 5.2 +/- 4.7 days (3.9 in completed and 7.9 days in converted cases). A total of 14 patients (32.6%) required conversion for dense adhesions (n = 8), duodenal involvement (n = 3), multiple fistulae (n = 1), fecal leak (n = 1), and additional pathology (n = 1). Conversion rates, analyzed by fistula type, were duodenal (100%), vaginal (66.7%), sigmoid (27.7%), bladder (15.4%), enterocolic (0%), and colocolic (0%). There were six major complications (14%) including anastomotic leak (n = 3), abscesses (n = 2), and postoperative bleeding (n = 1). There were seven minor complications (16.3%) including postoperative ileus (n = 2), transient pleural effusion (n = 1), wound infection (n = 1), transient small bowel obstruction (n = 2), and brachial plexus neuralgia (n = 1). There was no significant difference in the complication (p = 0.57), reoperation (p = 0.3), or readmission (p = 0.4) rates between the completed and converted cases. CONCLUSIONS: Laparoscopic surgery for benign internal enteric fistula offers the earlier recovery seen with other laparoscopic colorectal operations. Duodenal and vaginal involvement by the fistula is associated with a higher conversion rate. A low threshold toward early conversion is useful in these difficult cases to reduce delays in the operating room and the unnecessary use of hospital resources.

Adult↗
PubMed1997

High rates of actin filament turnover in budding yeast and roles for actin in establishment and maintenance of cell polarity revealed using the actin inhibitor latrunculin-A.

We report that the actin assembly inhibitor latrunculin-A (LAT-A) causes complete disruption of the yeast actin cytoskeleton within 2-5 min, suggesting that although yeast are nonmotile, their actin filaments undergo rapid cycles of assembly and disassembly in vivo. Differences in the LAT-A sensitivities of strains carrying mutations in components of the actin cytoskeleton suggest that tropomyosin, fimbrin, capping protein, Sla2p, and Srv2p act to increase actin cytoskeleton stability, while End3p and Sla1p act to decrease stability. Identification of three LAT-A resistant actin mutants demonstrated that in vivo effects of LAT-A are due specifically to impairment of actin function and implicated a region on the three-dimensional actin structure as the LAT-A binding site. LAT-A was used to determine which of 19 different proteins implicated in cell polarity development require actin to achieve polarized localization. Results show that at least two molecular pathways, one actin-dependent and the other actin-independent, underlie polarity development. The actin-dependent pathway localizes secretory vesicles and a putative vesicle docking complex to sites of cell surface growth, providing an explanation for the dependence of polarized cell surface growth on actin function. Unexpectedly, several proteins that function with actin during cell polarity development, including an unconventional myosin (Myo2p), calmodulin, and an actin-interacting protein (Bud6/Aip3p), achieved polarized localization by an actin-independent pathway, revealing interdependence among cell polarity pathways. Finally, transient actin depolymerization caused many cells to abandon one bud site or mating projection and to initiate growth at a second site. Thus, actin filaments are also required for maintenance of an axis of cell polarity.

Actin Cytoskeleton↗
PubMed1997

Crystallization and preliminary crystallographic analysis of the N-terminal actin binding domain of human fimbrin.

We have crystallized the N-terminal actin binding domain (ABD1) of human fimbrin, a representative member of the largest class of actin crosslinking proteins. Diffraction from these crystals is consistent with the orthorhombic space group P2(1)2(1)2(1) (a = 50.03 A, b = 61.24 A, c = 102.30 A). These crystals contain one molecule in the asymmetric unit and diffract to at least 1.9 A resolution. The crystal structure of ABD1 will be the first structure of an actin crosslinking domain.

Carrier Proteins↗
PubMed1995

Structure and in vitro molecular chaperone activity of cytosolic small heat shock proteins from pea.

Plants synthesize several classes of small heat shock proteins ranging in size from 15 to 30 kDa. Two conserved classes, designated class I and class II, are localized to the cytosol. Recombinant HSP18.1 and HSP17.7, representing class I and class II proteins from pea, respectively, were expressed in Escherichia coli and purified. Non-denaturing polyacrylamide gel electrophoresis and electron microscopy demonstrated that the purified proteins formed discretely sized, high molecular weight complexes. Sedimentation equilibrium analytical ultracentrifugation revealed that the HSP18.1 and HSP17.7 complexes were composed of approximately 12 subunits. Both proteins were able to enhance the refolding of chemically denatured citrate synthase and lactate dehydrogenase at stoichiometric levels in an ATP-independent manner. Furthermore, HSP18.1 and HSP17.7 prevented aggregation of citrate synthase at 45 degrees C and irreversible inactivation of citrate synthase at 38 degrees C. HSP18.1 also suppressed aggregation of lactate dehydrogenase at 55 degrees C. These findings demonstrate that HSP18.1 and HSP17.7 can function as molecular chaperones in vitro.

Citrate (si)-Synthase↗
PubMedDate not supplied

Review: protein design--where we were, where we are, where we're going.

Protein design has become a powerful approach for understanding the relationship between amino acid sequence and 3-dimensional structure. In the past 5 years, there have been many breakthroughs in the development of computational methods that allow the selection of novel sequences given the structure of a protein backbone. Successful design of protein scaffolds has now paved the way for new endeavors to design function. The ability to design sequences compatible with a fold may also be useful in structural and functional genomics by expanding the range of proteins used for fold recognition and for the identification of functionally important domains from multiple sequence alignments.

Protein Engineering↗