Low section of the rectum during laparoscopic total mesorectal excision using the Contour device. Technical report.
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Equipment Design↗
Biomedical subjects
J Garriga
Publications and source records attributed to J Garriga.
Predictive factors for successful laparoscopic splenectomy in immune thrombocytopenic purpura: study of clinical and laboratory data.
BACKGROUND: Laparoscopic splenectomy (LS) offers better short-term results than open surgery for the treatment of immune thrombocytopenic purpura (ITP), but long-term follow-up is required to ensure its efficacy. The remission rate after splenectomy ranges from 49 to 86% and the factors that predict a successful response to surgical management have not been clearly defined. The goal of this study was to determine the preoperative factors that predict a successful outcome following LS. METHODS: From February 1993 to December 2003, LS was consecutively performed in a series of 119 nonselected patients diagnosed with ITP (34 men and 85 women; mean age, 41 years), and clinical results were prospectively recorded. Postoperative follow-up was based on clinical records, follow-up data provided by the referring hematologist, and a phone interview with the patient and/or relative. Univariate and multivariate analyses were performed for clinical preoperative variables to identify predictive factors of success following LS. RESULTS: Over a mean period of 33 months, 103 patients (84%) were available for follow-up with a remission rate of 89% (92 patients, 77 with complete remission with platelet count > 150,000). Eleven patients did not respond to surgery (platelet count < 50,000). Mortality during follow-up was 2.5% (two cases not related to hematological pathology and one case without response to splenectomy). Preoperative clinical variables evaluated to identify predictive factors of response to surgery were sex, age, treatment (corticoids alone or associated with Ig or chemotherapy), other immune pathology, duration of disease, and preoperative platelet count. In a subgroup of 52 patients, we also evaluated the type of autoantibodies and corticoid doses required to maintain a platelet count > 50,000. Multivariate analysis showed that none of the variables evaluated could be considered as predictive factors of response to LS due to the high standard error. CONCLUSION: Long-term clinical results show that LS is a safe and effective therapy for ITP. However, a higher number of nonresponders is needed to determine which variables predict response to LS for ITP.
Adolescent↗
Mid term analysis of safety and quality of life after the laparoscopic repair of paraesophageal hiatal hernia.
BACKGROUND: Initial experience with the laparoscopic repair of paraesophageal and type III mixed hiatal hernias showed that it is safe and feasible, with excellent immediate and short-term results. However, after a longer follow-up, a recurrence rate of < or =40% has been demonstrated. Data related to the outcome of paraesophageal hernia repair and the recurrence rate are still lacking. Quality-of-life scores may offer a better means of assessing the impact of surgical treatment on the overall health status of patients. Therefore, we performed prospective evaluation of anatomic and/or symptomatic recurrences after paraesophageal or large hiatal hernia repair. In addition, we investigated the correlation between recurrence and the patient's quality of life. METHODS: All patients after who had undergone repair of paraesophageal of mixed hiatal hernia were identified prospectively from a database consisting of all patients who had had laparoscopic operations for gastroesophageal pathology at our hospital between February 1998 and December 2002. The preoperative symptoms were taken from patients' clinical files. In March 2003, all patients with > or =6 months of follow-up had a barium swallow and were examined for radiological and clinical signs of recurrence. Thereafter, the patients' quality of life after surgery was evaluated using three standard questionnaires (Short Form 36 [SF-36], Glasgow Dyspepsia Severity Score [GDSS], and Gastrointestinal Quality of Life Index [GIQLI]. RESULT: During the study period, 46 patients had been operated on. The mean age was 63 years (range, 28-93). Thirty seven of them had a follow-up of > or =6 months. Eight patients (21%) had postoperative gastrointestinal symptoms. Barium swallow was performed in 30 patients (81%) and showed a recurrence in six of them (20%). According to SF-36 and GDSS, the patients' postoperative quality of life reached normal values and did not differ significantly from the standard values for the Spanish population of similar age and with similar comorbidities. Successfully operated patients reached a GIQLI value comparable to the standard population. However, symptomatic patients had significantly lower GIQLI scores than the asymptomatic or the Rx-recurrent group. CONCLUSION: The laparoscopic treatment of large paraesophageal and mixed hiatal hernias is not only feasible and safe but also offers a good quality of life on a midterm basis. However, the anatomic and functional recurrence rate is high. The next step is to identify the subset of patients who are at risk of failure and to establish technical alternatives that would ensure the durability of the repair.
Adult↗
The fate of pancreatic tumor cell lines following p16 overexpression depends on the modulation of CDK2 activity.
Restitution of lost tumor-suppressor activities may be a promising strategy to target specifically cancer cells. However, the action of ectopically expressed tumor-suppressor genes depends on genetic background of tumoral cells. Ectopic expression of p16(INK4a) induces either cell cycle arrest or apoptosis in different pancreatic cancer cell lines. We examined the molecular mechanisms mediating these two different cellular responses to p16 overexpression. Ectopic expression of p16 leads to G1 arrest in NP-9 cells by redistributing p21/p27 CKIs and inhibiting cyclin-dependent kinase CDK2 activity. In contrast, in NP-18 cells cyclin E (CycE)/CDK2 activity is significantly higher and is not downregulated by p16-mediated redistribution of p21/p27. Moreover, inhibition of CDK4 activity with fascaplysine, which does not affect CycE/CDK2 activity, reduces pocket protein phosphorylation in both cell lines, but fails to induce growth arrest. Like overexpression of p16, fascaplysine induces apoptosis in NP-18 cells, suggesting that inhibition of D-type cyclin/CDK activity in cells with high levels of CycE/CDK2 activity activates an apoptotic pathway. Inhibition of CycE/CDK2 activity via ectopic expression of p21 in NP-18 cells overexpressing p16 induces growth arrest and prevents p16-mediated apoptosis. Accordingly, silencing of p21 expression by using small interfering RNA switches the fate of p16-expressing NP-9 cells from cell cycle arrest to apoptosis. Our data suggest that, after CDK4/6 inactivation, the fate of pancreatic tumor cells depends on the ability to modulate CDK2 activity.
Adenocarcinoma↗
Prospective randomized trial comparing conventional laparoscopic colectomy with hand-assisted laparoscopic colectomy: applicability, immediate clinical outcome, inflammatory response, and cost.
BACKGROUND: Hand-assisted laparoscopic surgery (HALS) represents a useful alternative to conventional laparoscopic surgery (LS). Its potential advantages--(a quicker, safer procedure and less need to convert to open surgery) are due to the recovery of tactile feedback. However, HALS requires the performance of a mini-laparotomy when surgery commences, and the wound is stretched and compressed throughout the procedure. In addition, it is associated with a more intense manipulation of the intraabdominal viscera. All of these factors increase the surgical trauma, it is not known whether HALS maintains the minimally invasive characteristics of conventional LS. Therefore, we set out to study the applicability, immediate clinical outcome, inflammatory response, and cost of HALS compared with conventional LS using colectomy as a model. METHODS: We performed a prospective randomized trial comparing laparoscopic-assisted colectomy with HAL colectomy. The aims of the study were to assess (a) perioperative features, including time, advantages, and conversion; (b) the patient's immediate clinical response, including recovery of bowel sounds, refeeding time, postoperative pain, local and general morbidity, and hospital stay; (c) the effect on the inflammatory response, using interleukin-6 (ILG) and C-reactive protein (CRP) measurements; (d) oncological issues, including intraoperative cytology and features of the specimen; and (d) the relative costs of the two procedures. RESULTS: A total of 54 patients were enrolled in the study, 27 laparoscopic and 27 HALS. The operative times were similar, but HALS was associated with a far lower conversion rate--7% vs 23%. Immediate clinical outcomes, oncological features, and costs were similar for the two procedures, but HALS was associated with a significantly greater increase in IL6 and CRP than the conventional laparoscopic procedure. CONCLUSION: This comparative study shows that HALS simplifies difficult intraoperative situations, reducing the need for conversion. Although it is a more aggressive procedure, HALS preserves the features of a minimally invasive approach, maintains all of the oncological features of conventional laparoscopic surgery, and does not increase the cost. HALS should therefore be considered as a useful adjunct when difficult situations arise during conventional laparoscopic colectomy.
Aged↗
E1A modulates phosphorylation of p130 and p107 by differentially regulating the activity of G1/S cyclin/CDK complexes.
We have previously shown that the adenoviral 12S E1A protein modulates the phosphorylation status of p130 and p107 without apparent changes in the cell cycle dependent phosphorylation of the retinoblastoma protein. Here we report on the mechanisms by which E1A modifies differentially the phosphorylation status of pocket proteins. In human U-2 OS osteosarcoma cells transiently expressing E1A, ectopic expression of D-type cyclins alone or combined, but not cyclins E and/or A, fully rescues E1A-mediated block in hyperphosphorylation of p130 to form 3. However, cyclins E and A, individually or together, induce hyperphosphorylation of p130 to species with intermediate mobility. Phosphopeptide maps indicate that E1A inhibits phosphorylation of sites phosphorylatable by CDKs. One of these sites is Ser-1044. The effects of blocking the activities of endogenous and exogenous cyclins with p16 and dominant negative CDK2 in E1A expressing cells further indicate that p130 is phosphorylated by both D-type cyclin and cyclin E/CDK complexes and that E1A modulates the activity of these G1/S CDKs by independent mechanisms. Stable expression of E1A in MC3T3-E1 cells leads to downregulation of D-type cyclins, and upregulation of cyclins E and A. This is accompanied by increased CDK2 kinase activity. Downregulation of D-type cyclins in these cells correlates with a block on both p130 hyperphosphorylation to form 3 and hyperphosphorylation of p107. This is rescued by D-type cyclins but not by cyclin E. In addition, we show that the upregulation of cyclins E and A is at least partially dependent on an intact pocket protein/E2F pathway, but downregulation of D-type cyclins is not. Moreover, we provide evidence that while the lack of a functional pRB pathway also results in a block on hyperphosphorylation of p130 to form 3, this is not sufficient to induce constitutive expression of p130 form 2b.
Adenovirus E1A Proteins↗
Gravity in the randall-sundrum brane world
We discuss the weak gravitational field created by isolated matter sources in the Randall-Sundrum brane world. For the case of a single wall of positive tension, the field stays localized near the wall if the source is stationary. We calculate the leading Kaluza-Klein corrections to the linearized gravitational field of a nonrelativistic spherical object, which is different from the Schwarzschild solution at large distances. In the case of two branes of opposite tension, linearized Brans-Dicke (BD) gravity is recovered on either wall, with different BD parameters. On the wall with positive tension the BD parameter is larger than 3000 provided that the separation between walls is larger than 4 times the AdS radius. The gravitational field due to shadow matter is also considered.
Journal Article↗
Applicability of laparoscopic surgery for colorectal disease.
BACKGROUND: The advantages of laparoscopic colorectal surgery for selected patients have been well established. However, the applicability of laparoscopic surgery in the whole population of patients with colorectal disease is not well known. METHODS: A single-institution medical records review of 269 patients subjected to colorectal surgery was made. Of these, 206 open colorectal procedures were performed, and data were reviewed retrospectively. In addition, 63 patients were subjected to laparoscopy, and their data were recorded prospectively. An analysis of the existence of factors that contraindicate laparoscopic colorectal surgery was done. These factors were of two types: absolute (urgent intervention, severe cardiopulmonary disease, advanced liver cirrhosis, tumor invasion into adjacent organs, simultaneous major surgery) and relative (midrectal tumors, tumors in the transverse colon, bulky tumors, more than two previous infraumbilical operations, previous intestinal surgery, and previous peritonitis). RESULTS: Factors that could contraindicate the laparoscopic approach were found in 118 patients (44%). The most common were urgent intervention (40%), midrectal tumors (19%), locally advanced cancer (13%), previous intestinal surgery (13%), and tumors >10 cm (6%). We considered 25% of the contraindications to be absolute and 19% relative. Taking these exclusion criteria into consideration when selecting patients for laparoscopic surgery, the conversion rate in our initial laparoscopic series (63 cases) was 13%. CONCLUSION: The indication for laparoscopic surgery for patients with colorectal disease is superior to 60% (absolute 56%, relative 81%). When using appropriate selection criteria, the conversion rate may be maintained below 10%. Preoperative selection of patients with colorectal disease allows optimal use of the advantages of laparoscopic surgery.
Adult↗
E1A blocks hyperphosphorylation of p130 and p107 without affecting the phosphorylation status of the retinoblastoma protein.
The phosphorylation status of the pRB family of growth suppressor proteins is regulated in a cell cycle entry-, progression-, and exit-dependent manner in normal cells. We have shown previously that p130, a member of this family, exhibits patterns of phosphorylated forms associated with various cell growth and differentiation stages. However, human 293 cells, which are transformed cells that express the adenoviral oncoproteins E1A and E1B, exhibit an abnormal pattern of p130 phosphorylated forms. Here we report that, unlike pRB, the phosphorylation status of both p130 and p107 is not modulated during the cell cycle in 293 cells as it is in other cells. Conditional overexpression of individual G(1)/S cyclins in 293 cells does not alter the phosphorylation status of p130, suggesting that the expression of E1A and/or E1B blocks hyperphosphorylation of p130. In agreement with these observations, transient cotransfection of vectors expressing E1A 12S, but not E1B, in combination with pocket proteins into U-2 OS cells blocks hyperphosphorylation of both p130 and p107. However, the phosphorylation status of pRB is not altered by cotransfection of E1A 12S vectors. Moreover, MC3T3-E1 preosteoblasts stably expressing E1A 12S also exhibit a block in hyperphosphorylation of endogenous p130 and p107. Direct binding of E1A to p130 and p107 is not required for the phosphorylation block since E1A 12S mutants defective in binding to the pRB family also block hyperphosphorylation of p130 and p107. Our data reported here identify a novel function of E1A, which affects p130 and p107 but does not affect pRB. Since E1A does not bind the hyperphosphorylated forms of p130, this function of E1A might prevent the existence of "free" hyperphosphorylated p130, which could act as a CDK inhibitor.
Cell Line↗
[Laparoscopic treatment of colorectal polyps].
UNLABELLED: Endoscopic removal is the treatment of choice for colorectal polyps. However, this therapeutic option is limited by the size of the tumor, sessile implantation, or technical impossibility. These cases are ideal for laparoscopic treatment because of the anatomy of the colon is and because the risk of manipulating a malignant lesion is lower. However, there is the added difficulty of identifying the lesion. In other cases, unsuspected neoplastic invasion of an endoscopically removed polyp makes surgery necessary. AIM: To evaluate the results of laparoscopic surgery in the treatment of colorectal polyps. MATERIAL AND METHODS: Between December 1997 and November 1999, 270 endoscopic polypectomies were performed. In 15 patients, endoscopic removal was technically impossible or contraindicated. These patients were treated laparoscopically. One patient who was found to have an invasive carcinoma following polypectomy was also treated laparoscopically. The technical characteristics of the operation (duration, conversion, morbi-mortality, postoperative stay, size of the polyp and number of ganglions) were analyzed and compared with 43 other laparoscopic operations in the colon carried out for other reasons (n = 43). RESULTS: In nine patients, surgery was indicated because of the size of the polyp, in three for technical reasons, in three for severe atypia and in one because of an invasive carcinoma following polypectomy. The operation was completed by laparoscopy in 15 patients (94%). Ten right hemicolectomies, five sigmoidectomies and one anterior resection assisted by hand port were carried out. The diameter of the lesions was 4.4 +/- 2.4 cm. Histological studies revealed carcinoma in situ in five, infiltrating carcinoma in two, non-malignant adenoma in six and lipoma in one. Comparison of the results of patients who underwent colectomy for polyps with those of the group who underwent surgery for other reasons revealed lower morbidity (24% vs. 22%) and need for conversion (7% vs. 16%), as well as a significant decrease in operating time (130 +/- 10 vs. 148 +/- 32 min, p < 0.05) and in postoperative stay (6.6 +/- 1.4 vs. 8.3 +/- 2.5 days, p < 0.02). CONCLUSION: Laparoscopic colonic resection is particularly suitable in the treatment of colorectal polyps.
Adult↗
Role of the retinoblastoma protein family, pRB, p107 and p130 in the negative control of cell growth.
The retinoblastoma family of proteins, also known as pocket proteins, includes the product of the retinoblastoma susceptibility gene and the functionally and structurally related proteins p107 and p130. Pocket proteins control growth processes in many cell types, and this has been linked to the ability of pocket proteins to interact with a multitude of cellular proteins that regulate gene expression at various levels. By regulating gene expression, pocket proteins control cell cycle progression, cell cycle entry and exit, cell differentiation and apoptosis. This review will focus on the mechanisms of regulation of pocket proteins and how modulation of pocket protein levels and phosphorylation status regulate association with their cellular targets. The coordinated regulation of pocket proteins provides the cells with a competence mechanism for passage through certain cell growth and differentiation transitions.
Animals↗
Upregulation of cyclin T1/CDK9 complexes during T cell activation.
Cyclin T1 has been identified recently as a regulatory subunit of CDK9 and as a component of the transcription elongation factor P-TEFb. Cyclin T1/CDK9 complexes phosphorylate the carboxy terminal domain (CTD) of RNA polymerase II (RNAP II) in vitro. Here we report that the levels of cyclin T1 are dramatically upregulated by two independent signaling pathways triggered respectively by PMA and PHA in primary human peripheral blood lymphocytes (PBLs). Activation of these two pathways in tandem is sufficient for PBLs to enter and progress through the cell cycle. However, the expression of cyclin T1 is not growth and/or cell cycle regulated in other cell types, indicating that regulation of cyclin T1 expression is dependent on tissue-specific signaling pathways. Upregulation of cyclin T1 in stimulated PBLs results in induction of the CTD kinase activity of the cyclin T1/CDK9 complex, which in turn correlates directly with phosphorylation of RNAP II in vivo, linking for the first time activation of the cyclin T1/ CDK9 pair with phosphorylation of RNAP II in vivo. In addition, we report here that endogenous CDK9 and cyclin T1 complexes associate with HIV-1 generated Tat in relevant cells and under physiological conditions (HIV-1 infected T cells). This, together with our results showing that HIV-1 replication in stimulated PBLs correlates with the levels of cyclin T1 protein and associated CTD kinase activity, suggests that the cyclin T1/CDK9 pair is one of the HIV-1 required host cellular cofactors generated during T cell activation.
Cell Cycle↗
Differential regulation of the retinoblastoma family of proteins during cell proliferation and differentiation.
In the present study we have analysed the regulation of pocket protein expression and post-transcriptional modifications on cell proliferation and differentiation, both in vivo and in vitro. There are marked changes in pocket protein levels during these transitions, the most striking differences being observed between p130 and p107. The mechanisms responsible for regulating pocket protein levels seem to be dependent on both cell type and pocket protein, in addition to their dependence on the cell growth status. Changes in retinoblastoma protein and p107 levels are independent of their state of phosphorylation. However, whereas p130 phosphorylation to forms characteristic of quiescent/differentiated cells results in the accumulation of p130 protein, phosphorylation of p130 to one or more forms characteristic of cycling cells is accompanied by down-regulation of its protein levels. We also show here that the phosphorylation status and protein levels of p130 and p107 are regulated in vivo as in cultured cells. In vivo, changes in p130 forms are correlated with changes in E2F complexes. Moreover, the modulation of p130 and p107 status during cell differentiation in vitro is consistent with the patterns of protein expression and phosphorylation status found in mouse tissues. Thus in addition to the direct disruption of pocket protein/E2F complexes induced by cyclin/cyclin-dependent kinase, the results we report here indicate that the differential modulation of pocket protein levels constitutes a major mechanism that regulates the pool of each pocket protein that is accessible to E2F and/or other transcription factors.
3T3 Cells↗
The ability of positive transcription elongation factor B to transactivate human immunodeficiency virus transcription depends on a functional kinase domain, cyclin T1, and Tat.
By binding to the transactivation response element (TAR) RNA, the transcriptional transactivator (Tat) from the human immunodeficiency virus increases rates of elongation rather than initiation of viral transcription. Two cyclin-dependent serine/threonine kinases, CDK7 and CDK9, which phosphorylate the C-terminal domain of RNA polymerase II, have been implicated in Tat transactivation in vivo and in vitro. In this report, we demonstrate that CDK9, which is the kinase component of the positive transcription elongation factor b (P-TEFb) complex, can activate viral transcription when tethered to the heterologous Rev response element RNA via the regulator of expression of virion proteins (Rev). The kinase activity of CDK9 and cyclin T1 is essential for these effects. Moreover, P-TEFb binds to TAR only in the presence of Tat. We conclude that Tat-P-TEFb complexes bind to TAR, where CDK9 modifies RNA polymerase II for the efficient copying of the viral genome.
Cell Line, Transformed↗
Phosphorylation site specificity of the CDC2-related kinase PITALRE.
PITALRE is a human protein kinase belonging to the cell division cycle 2 (CDC2) kinase family, and is the catalytic subunit of a multimeric complex that contains several cellular proteins. PITALRE complexes from several cell lines and tissues phosphorylate retinoblastoma protein and myelin basic protein (MBP). In the present work, we have found that MBP is phosphorylated by PITALRE complexes on both Ser and Thr residues. Two different antibodies raised to PITALRE purified virtually identical kinase activities, as analysed by MBP phosphopeptide mapping and phosphoamino acid analysis. We have identified the proline-directed residue Ser-162 of MBP as a major phosphorylation site for PITALRE. In addition, our results suggest that one of the two MBP proline-directed threonine residues, Thr-97, is also selectively phosphorylated by PITALRE. These data, together with analysis of different peptide substrates derived from sites on MBP that are phosphorylated by PITALRE, indicate that PITALRE is a Ser/Thr proline-directed kinase. In addition, our results show that PITALRE has a substrate site specificity distinguishable from those of the CDC2 and cyclin-dependent kinase 2 (CDK2).
Amino Acid Sequence↗
Bubble fluctuations in Omega <1 inflation.
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Journal Article↗
The CDC2-related kinase PITALRE is the catalytic subunit of active multimeric protein complexes.
PITALRE is a human protein kinase identified by means of its partial sequence identity to the cell division cycle regulatory kinase CDC2. Immunopurified PITALRE protein complexes exhibit an in vitro kinase activity that phosphorylates the retinoblastoma protein, suggesting that PITALRE catalyses this phosphorylation reaction. However, the presence of other kinases in the immunopurified complex could not be ruled out. In the present work, an inactive mutant of the PITALRE kinase has been used to demonstrate that PITALRE is the catalytic subunit responsible for the PITALRE-complex-associated kinase activity, Ectopic overexpression of PITALRE did not increase the total PITALRE kinase activity in the cell, suggesting that PITALRE is regulated by limiting cellular factor(s). Characterization of the PITALRE-containing protein complexes indicated that most of the cellular PITALRE protein exists as a subunit in at least two different active multimeric complexes. Although monomeric PITALRE is also active in vitro, PITALRE present in multimeric complexes exhibits several-fold higher activity than monomeric PITALRE. In addition, overexpression of PITALRE demonstrated the existence of two new associated proteins of approx. 48 and 98 kDa. Altogether these results suggest that, in contrast to the situation with cyclin-dependent kinases, monomeric PITALRE is active, and that association with other proteins modulates its activity and/or its ability to recognize substrates in vivo.
Amino Acid Sequence↗
G1 cyclin/CDK-independent phosphorylation and accumulation of p130 during the transition from G1 to G0 lead to its association with E2F-4.
During the transition from G1 to G0, p130 undergoes a specific phosphorylation event-leading to p130-form 2- that is mediated by a kinase/s other than the known G1, S and G2/M cyclin/CDKs. Changes in the phosphorylation status of p130 during this transition are responsible, at least in part, for the concomitant formation of p130/E2F-4 complexes, which are characteristic of G0. These complexes remain abundant during early G1 upon restimulation, but not after mitosis, and are dissociated in mid G1 when p130 is abruptly hyperphosphorylated to form 3. Subsequently, p130 forms 1 and 2 are no longer detected during the remainder of the cell cycle. Consistently, phosphorylation to form 3 and dissociation from E2F-4 complexes is reproduced by a cyclin/CDK holoenzyme in vitro. TGF-beta-induced G1 arrest abrogates cyclin/CDK phosphorylation of p130 but not phosphorylation to form 2. The cell cycle-dependent phosphorylation pattern of p130 is thus shown to comprise two distinct steps that are catalyzed by different kinases. The differential regulation of p130 and pRB phosphorylation during the transition from G1 to G0 may explain the fact that p130 and E2F-4 are the major components of E2F complexes in quiescent cells. Moreover, the newly described phosphorylation of p130 at the transition from G1 to G0 defines a novel mechanism of cell cycle exit regulation.
3T3 Cells↗