Biomedical subjects

M Bessler

Publications and source records attributed to M Bessler.

At least 19 recordsLinked to original sources

PubMed2006

Preoperative esophageal manometry and outcome of laparoscopic adjustable silicone gastric banding.

BACKGROUND: Laparoscopic adjustable silicone gastric banding (LASGB) for morbid obesity has been reported to provide long-term weight loss with a low risk of operative complications. Nevertheless, esophageal dilation leading to achalasia-like and reflux symptoms is a feared complication of LASGB. This study evaluates the clinical benefit of routine preoperative esophageal manometry in predicting outcome after LASGB in morbidly obese patients. METHOD: A review of prospectively collected data on 77 patients who underwent routine esophageal manometry prior to LASGB for morbid obesity from February 2001 to September 2003 was performed. Aberrant motility, abnormal lower esophageal sphincter (LES) pressures, and other nonspecific esophageal motility disorders noted on preoperative esophageal manometry defined patients of the abnormal manometry group. Outcome differences in weight loss, emesis, band complications, and gastroesophageal reflux disease (GERD) resolution or improvement were compared between patients of the abnormal and normal manometry groups after LASGB. Analysis of variance (ANOVA) and chi-square tests were performed to determine the significance of these outcomes. RESULTS: Of the patients tested, 14 had abnormal esophageal manometry results, whereas 63 had normal manometry results before LASGB. There was no significant difference in percent excess weight loss (%EWL) at 6 and 12 months between the groups after gastric banding. Severe postoperative emesis occurred more frequently in patients with abnormal manometry results than in those with normal manometry results. There were two band-related complications, both of which occurred in patients of the normal manometry group. CONCLUSIONS: Preoperative esophageal manometry does not predict weight loss or GERD outcomes after LASGB in morbidly obese patients. Postoperative emesis was more common in patients with abnormal manometry findings, but such symptoms were manageable and did not lead to poor weight loss or to band removal or increased band-related complications.

Adult↗

PubMed2005

Early U.S. outcomes of laparoscopic gastric bypass versus laparoscopic adjustable silicone gastric banding for morbid obesity.

Laparoscopic gastric bypass (LGBP) is the gold standard operation for long-term weight control in the United States. Laparoscopic adjustable silicone gastric banding (LASGB) is the preferred operative method for morbid obesity worldwide. Limited data are available comparing the two procedure in the United States. This study compares weight loss, complications, and early outcome of comorbidity resolution in patients who underwent LGBP versus LASGB. A review of prospectively collected data was performed on 392 patients undergoing primary LGBP (n = 232) and LASGB (n = 160) procedures between February 2001 and July 2004. Differences in percentage excess weight lost (%EWL) at 3, 6, 12, 18, and 24 months postop, improvement or resolution of comorbidities, and complications across procedure types were evaluated. Mean initial body mass index between groups was not significantly different (LGBP 47.2 vs LASGB 47.1, p < 0.53). There were significant differences in age, gender, and self-reported sweet-eating behavior between operative groups. There was a significantly greater %EWL in patients who underwent LGBP compared to patients of the LASGB groups 3, 6, 12, and 18 months after surgery. There were no significant differences in resolution or improvement of comorbidities between the groups. Although LGBP patients experienced more complications compared to LASGB patients (5.6 vs 4.3%, respectively; p < 0.56), this did not reach statistical significance. Early after surgery, LGBP patients lose more weight than LASGB patients but have similar improvements in comorbidities. Further follow-up is needed to determine the relative long-term efficacy of these procedures.

Adult↗

PubMed2005

Dyskeratosis congenita -- a disease of dysfunctional telomere maintenance.

Dyskeratosis congenita (DC) is a rare inherited bone marrow failure syndrome associated with abnormalities of the skin, fingernails, and tongue. Other clinical manifestations may include epiphora, lung fibrosis, liver cirrhosis, osteoporosis, and a predisposition to develop a variety of malignancies. The clinical picture often resembles that of a premature aging syndrome and tissues affected are those with a high cell turnover. DC has been linked to mutations in at least four distinct genes, three of which have been identified. The product of these genes, dyskerin, the telomerase RNA (TERC), and the catalytic unit of telomerase (TERT) are part of a ribonucleoprotein complex, the telomerase enzyme, that is essential for the elongation and maintenance of chromosome ends or telomeres. All patients with DC have excessively short telomeres, indicating that the underlying defect in these individuals is an inability to maintain the telomeres. The purpose of the current review is to highlight recent insights into the molecular pathogenesis of DC. We discuss the impact these findings have on our current understanding of telomere function and maintenance, and on the diagnosis, management, and treatment of patients with conditions caused by dysfunctional telomeres.

Chromosomes, Human, X↗

PubMed2003

Postoperative cell mediated immune response is better preserved after laparoscopic vs open colorectal resection in humans.

BACKGROUND: Animal studies have documented significantly better preserved postoperative cell-mediated immune function, as measured by serial delayed-type hypersensitivity (DTH) challenges, after laparoscopic-assisted than after open bowel resection. Similarly, in humans, the DTH responses after open cholecystectomy have been shown to be significantly smaller than preoperative responses; whereas after laparoscopic cholecystectomy, no significant change in DTH response has been noted. The purpose of this study was to assess cell-mediated immune function via serial DTH skin testing in patients undergoing laparoscopic or open colectomy. METHODS: A total of 35 subjects underwent either laparoscopic (n = 18) or open colectomy (n = 17) in this prospective but not randomized study. Only patients who were judged to be immunoresponsive by virtue of having responded successfully to a preoperative DTH challenge were eligible for entry in the study. DTH challenges were carried out at three time points in all patients: preoperatively, immediately following surgery, and on the third postoperative day (POD 3). Responses were measured 48 h after each challenge and the area of induration calculated. There were no significant differences between the laparoscopic (LC) and open (OC) colorectal resection groups in regard to demographics, indications for surgery, or type of resection carried out. The percentage of patients transfused was similar in both groups (17%, LC; 12% OC; p = NS). In the LC group, all cases were completed without conversion using minimally invasive methods. There were no perioperative deaths, and the rate of postoperative complications was similar in both groups. The preoperative and postoperative DTH results were analyzed and compared within each surgical group using several methods. RESULTS: In regards to the OC group results, the median sum-total DTH responses for the day of surgery challenges (0.44 +/- 69 cm2) and the POD 3 challenges (0.72 +/- 3.37 cm2) were significantly smaller than the preoperative results (3.61 +/- 3.83 cm2, p <0.0005 vs op day and p <0.0003 vs POD 3 results). When the LC group results were similarly analyzed, no significant difference in DTH response was noted between the pre- and the postoperative challenge results. Additionally, when the median percent change from baseline was calculated and considered for the OC group's DTH results, both postoperative challenge time points demonstrated significantly decreased responses when compared to their preoperative results (vs day of surgery, p <0.007; vs POD 3, p <0.006). Similar analysis of the LC group's results yielded nonsignificant differences between the pre- and postoperative responses. Lastly, when the LC and the OC groups median percent change from baseline results were directly compared for each of the postoperative challenges, a significant difference was noted for the POD 0 challenge (LC, -21%; OC 88%; p <0.004) but not for the POD 3 challenge. CONCLUSIONS: The postoperative DTH responses of the open surgery patients were significantly smaller than their preoperative responses. This was not the case for the laparoscopic group (a combination of fully laparoscopic and laparoscopic-assisted resections). When the open and laparoscopic groups results are directly compared, regarding the results of the day of surgery DTH challenges, the LC groups median percent change from baseline was significantly less than that observed in the OC group. These results imply that open colorectal resection is associated with a significant suppression of cell-mediated immune response postoperatively, whereas in this study laparoscopic colorectal resection was not. Further human studies are needed to verify these findings and to determine the clinical significance, if any, of this temporary difference in immune function following colon resection.

Antigens, Fungal↗

PubMed2002

Increased rates of pulmonary metastases following sham laparotomy compared to CO2 pneumoperitoneum and the inhibition of metastases utilizing perioperative immunomodulation and a tumor vaccine.

BACKGROUND: Subcutaneous tumor growth and establishment is increased after laparotomy; significantly smaller increases have been noted after CO2pneumoperitoneum (CO2 pneumo). Less is known about the impact of surgery on the fate of blood borne tumor cells. The extent of surgical abdominal wall trauma also correlates with the extent of early postoperative immunosuppression and the inflammatory response. These changes may favor lung metastases (mets) formation. This study's hypotheses were: (a) a reduction in surgical trauma or (b) a perioperative (periop) tumor vaccine or nonspecific immune up-regulation would limit lung mets formation. An intravenous tumor cell injection lung met model was used to test these hypotheses. METHODS: Study 1 determined the incidence of lung mets after sham laparotomy (OP) and CO2 pneumo. Three groups were studied (n=25/group) : Anesthesia control (AC), CO2 pneumo, and OP. 1 x 105 TA3Haushka adenocarcinoma cells were inoculated via tail vein injection into all mice immediately after surgery. Study 2 determined the impact of perioperative immunomodulation on lung mets formation. Five groups were studied (n=20/group) : AC, OP, OP + Monophosphoryl Lipid A (MPLA), OP + lysed tumor cells (LTC), or OP + MPLA + LTC. The vaccine consisted of 5 x 105 lysed TA3Ha tumor cells (LTC) and was given 5 times preop and once postop to the vaccine groups. MPLA, the nontoxic moiety of lipopolysaccharide, was used both as a vaccine adjuvant in the OP + MPLA + LTC group and as a nonspecific perioperative immune up-regulator in the OP + MPLA group. Five periop injections of MPLA were given to the OP + MPLA group. All mice were given tail vein injections of tumor cells after surgery. Fourteen days after surgery all mice were sacrificed, the lungs transected en bloc, and India ink injected into the trachea. The lungs were placed in Fekete's solution to counterstain the tumor foci white. The number of surface lung metastases was determined by two blinded observers, separately. RESULTS: In Study 1, there were significantly more lung tumors in the OP group (median=31.5) than the AC group (median=9; p<0.05) or the CO2 Pneumo group (median=6.5; p<0.05). There were no significant differences in the number of metastases between the AC and the CO2 Pneumo groups or in the incidence of animals in each group with 1 or more lung mets. In Study 2 significantly fewer metastases were noted for the Op + LTC group (median=3; p<0.05) and the OP + LTC + MPLA group (median=0; p<0.05) when compared to the OP group (median=20). Although the OP + MPLA group mice had fewer metastases (median=4) than the OP group, this difference was not significant. Significantly fewer of the OP + LTC + MPLA group mice developed one or more lung tumors than in the OP, OP + MPLA, and the OP + LTC groups. CONCLUSIONS: Full sham laparotomy was associated with more postoperative lung metastases than CO2 pneumo or anesthesia alone in this murine model. Up-regulation of the immune system in the perioperative period with lysed tumor cells, alone or in combination with MPLA, resulted in significantly fewer postoperative lung metastases. MPLA alone resulted in a less marked reduction of lung metastases.

Adenocarcinoma↗

PubMed2002

Dynamics of hematopoiesis in paroxysmal nocturnal hemoglobinuria (PNH): no evidence for intrinsic growth advantage of PNH clones.

PNH is characterized by expansion of one or more stem cell clones with a PIG-A mutation, which causes a severe deficiency in the expression of glycosylphosphatidylinositol (GPI)-anchored proteins. There is evidence that the expansion of PIG-A mutant clones is concomitant with negative selection against PIG-A wild-type stem cells by an aplastic marrow environment. We studied 36 patients longitudinally by serial flow cytometry, and we determined the proportion of PNH red cells and granulocytes over a period of 1-6 years. We observed expansion of the PNH blood cell population(s) (at a rate of over 5% per year) in 12 out of 36 patients; in all other patients the PNH cell population either regressed or remained stable. The dynamics of the PNH cell population could not be predicted by clinical or hematologic parameters at presentation. These data indicate that in most cases the PNH cell expansion has already run its course by the time of diagnosis. In addition, since in most cases no further expansion takes place, we can infer that the tendency to overgrow normal cells is not an intrinsic property of the PNH clone.

Adolescent↗

PubMed2001

GATA1-Cre mediates Piga gene inactivation in the erythroid/megakaryocytic lineage and leads to circulating red cells with a partial deficiency in glycosyl phosphatidylinositol-linked proteins (paroxysmal nocturnal hemoglobinuria type II cells).

Patients with paroxysmal nocturnal hemoglobinuria (PNH) have blood cells deficient in glycosyl phosphatidylinositol (GPI)-linked proteins owing to a somatic mutation in the X-linked PIGA gene. To target Piga recombination to the erythroid/megakaryocytic lineage in mice, the Cre/loxP system was used, and Cre was expressed under the transcriptional regulatory sequences of GATA-1. Breeding of GATA1-cre (G) transgenic mice with mice carrying a floxed Piga (L) allele was associated with high embryonic lethality. However, double-transgenic (GL) mice that escaped early recombination looked healthy and were observed for 16 months. Flow cytometric analysis of peripheral blood cells showed that GL mice had up to 100% of red cells deficient in GPI-linked proteins. The loss of GPI-linked proteins on the cell surface occurred late in erythroid differentiation, causing a proportion of red cells to express low residual levels of GPI-linked proteins. Red cells with residual expression of GPI-linked proteins showed an intermediate sensitivity toward complement and thus resemble PNH type II cells in patients with PNH. Recombination of the floxed Piga allele was also detected in cultured megakaryocytes, mast cells, and eosinophils, but not in neutrophils, lymphocytes, or nonhematopoietic tissues. In summary, GATA1-Cre causes high-efficiency Piga gene inactivation in a GATA-1-specific pattern. For the first time, mice were generated that have almost 100% of red cells deficient in GPI-linked proteins. These animals will be valuable to further investigate the consequences of GPI-anchor deficiency on erythroid/megakaryocytic cells.

Animals↗

PubMed2001

The RNA component of telomerase is mutated in autosomal dominant dyskeratosis congenita.

Dyskeratosis congenita is a progressive bone-marrow failure syndrome that is characterized by abnormal skin pigmentation, leukoplakia and nail dystrophy. X-linked, autosomal recessive and autosomal dominant inheritance have been found in different pedigrees. The X-linked form of the disease is due to mutations in the gene DKC1 in band 2, sub-band 8 of the long arm of the X chromosome (ref. 3). The affected protein, dyskerin, is a nucleolar protein that is found associated with the H/ACA class of small nucleolar RNAs and is involved in pseudo-uridylation of specific residues of ribosomal RNA. Dyskerin is also associated with telomerase RNA (hTR), which contains a H/ACA consensus sequence. Here we map the gene responsible for dyskeratosis congenita in a large pedigree with autosomal dominant inheritance. Affected members of this family have an 821-base-pair deletion on chromosome 3q that removes the 3' 74 bases of hTR. Mutations in hTR were found in two other families with autosomal dominant dyskeratosis congenita.

Cell Line↗

PubMed2001

FES-Cre targets phosphatidylinositol glycan class A (PIGA) inactivation to hematopoietic stem cells in the bone marrow.

A somatic mutation in the X-linked phosphatidylinositol glycan class A (PIGA) gene causes the loss of glycosyl phosphatidylinositol (GPI)-linked proteins on blood cells from patients with paroxysmal nocturnal hemoglobinuria. Because all blood cell lineages may be affected it is thought that the mutation occurs in a hematopoietic stem cell. In transgenic mice, germline transmission of an inactive Piga gene is embryonic lethal. To inactivate the murine Piga gene in early hematopoiesis we therefore chose conditional gene inactivation using the Cre/loxP system. We expressed Cre recombinase under the transcription regulatory sequences of the human c-fes gene. FES-Cre inactivated PIGA in hematopoietic cells of mice carrying a floxed Piga allele (LF mice). PIGA(-) cells were found in all hematopoietic lineages of definitive but not primitive hematopoiesis. Their proportions were low in newborn mice but subsequently increased continuously to produce for the first time mice that have almost exclusively PIGA(-) blood cells. The loss of GPI-linked proteins occurred mainly in c-kit(+)CD34(+)Lin(-) progenitor cells before the CFU-GEMM stage. Using bone marrow reconstitution experiments with purified PIGA(-) cells we demonstrate that LF mice have long-term bone marrow repopulating cells that lack GPI-linked proteins, indicating that recombination of the floxed Piga allele occurs in the hematopoietic stem cell.

Animals↗

PubMed2001

Increased platelet-derived growth factor (PDGF) release after laparotomy stimulates systemic tumor growth in mice.

BACKGROUND: Our laboratory has demonstrated that tumors grow larger and are more easily established following laparotomy than after carbon dioxide (CO2) pneumoperitoneum or anesthesia alone. We have also shown that tumor cells incubated with serum from laparotomized mice proliferated significantly faster in vitro than those incubated with plasma from mice that underwent laparoscopy or anesthesia alone. We hypothesized that differing levels of a plasma-soluble growth factor(s) postoperatively causes tumors to proliferate faster after laparotomy. This study's purpose was to isolate and characterize the plasma growth factor(s) responsible for the increased growth of systemic tumors after laparotomy. METHODS: Female Balb/C mice (n = 100) were randomized to two groups: anesthesia control (AC) or midline sham laparotomy (4 cm) (Open). Plasma was collected on Postoperative day 4. For the tumor proliferation assay, C-26 colon cancer cells were incubated in media with either 10% AC or Open "raw" plasma (not passed through column), or AC or Open plasma that had been passed through the column. For elution of heparin-binding proteins, plasma from each group was passed through a heparin-sepharose column. Elution of bound proteins was accomplished with a 0.1-2 M NaCl gradient. Each fraction was examined for protein content. For the anti-platelet-derived growth factor (PDGF) neutralizing antibody study, C-26 cells were incubated with one of four plasma preparations: AC or Open plasma alone, or AC or Open plasma incubated with anti-PDGF antibody. For both studies, tumor proliferation was determined after 2 days with an MTS/PMS assay. Results from each group were compared and differences determined using analysis of variance (ANOVA) and Tukey-Kramer tests. RESULTS: On heparin chromatography, a single elution peak consistent with PDGF was present in both AC and Open plasma and was 1.5 times greater in the Open plasma. The first tumor proliferation assay showed that tumor cells incubated with Open plasma proliferated 2.5 times faster than those with AC plasma (p < 0.0001). Passage of AC plasma through the column did not alter its mitogenic activity, but Open plasma thus treated demonstrated significantly decreased mitogenic activity. The second tumor proliferation assay showed that anti-PDGF antibody had no effect on the mitogenic activity of the AC plasma but decreased the mitogenic activity of the Open plasma to the AC plasma level. CONCLUSIONS: Laparotomy is associated with higher levels of a heparin-binding plasma factor, consistent with PDGF. The enhanced mitogenic activity of the OP plasma was neutralized with anti-PDGF antibody. Increased plasma levels of PDGF after laparotomy may be responsible for accelerated tumor growth following laparotomy in mice.

Adenocarcinoma↗

PubMed2001

Cytogenetic and morphological abnormalities in paroxysmal nocturnal haemoglobinuria.

Paroxysmal nocturnal haemoglobinuria (PNH) is characterized by the expansion of a haematopoietic stem cell clone with a PIG-A mutation (the PNH clone) in an environment in which normal stem cells are lost or failing: it has been hypothesized that this abnormal marrow environment provides a relative advantage to the PNH clone. In patients with PNH, generally, the karyotype of bone marrow cells has been reported to be normal, unlike in myelodysplastic syndrome (MDS), another clonal condition in which cytogenetic abnormalities are regarded as diagnostic. In a retrospective review of 46 patients with a PNH clone, we found a karyotypic abnormality in 11 (24%). Upon follow-up, the proportion of cells with abnormal karyotype decreased significantly in seven of these 11 patients. Abnormal morphological bone marrow features reminiscent of MDS were common in PNH, regardless of the karyotype. However, none of our patients developed excess blasts or leukaemia. We conclude that in patients with PNH cytogenetically abnormal clones are not necessarily malignant and may not be predictive of evolution to leukaemia.

Adolescent↗

PubMed2001

Paroxysmal nocturnal hemoglobinuria: insights from recent advances in molecular biology.

Paroxysmal nocturnal hemoglobinuria (PNH) is a rare, acquired hemolytic anemia characterized by the increased sensitivity of red cells to complement, leading to intravascular hemolysis and hemoglobinuria. Other clinical features are cytopenias caused by bone marrow failure and an increased risk of thrombosis. If unrecognized and not treated appropriately, PNH is often associated with a substantial morbidity and mortality. PNH is caused by the expansion of a hematopoietic progenitor cell that caries a somatic mutation in the X-linked phosphatidylinositol glycan complementation group A (PIGA) gene. The PIGA gene encodes a protein essential in the biosynthesis of glycosylphosphatidylinositol (GPI)-anchor molecules. A proportion of blood cells from patients with PNH is therefore deficient in all GPI-linked surface proteins. Considerable progress in the field of PNH research in the last 7 years has resulted from the cloning of the PIGA gene. The purpose of the current article is to describe the structure and function of the PIGA gene, to summarize the lessons learned from the analysis of PIGA gene mutations, to review the impact of mouse models on our current understanding of the human disease, and to discuss the possible pathogenesis of PNH. In addition, we will outline novel approaches to PNH diagnosis, research, and therapy that became available thanks to the cloning of the PIGA gene.

Animals↗

PubMed2000

Lymphocyte proliferation in mice after a full laparotomy is the same whether performed in a sealed carbon dioxide chamber or in room air.

PURPOSE: Our laboratory has demonstrated that significantly more cell-mediated immunosuppression occurs after full laparotomy than after either anesthesia control or carbon dioxide (CO2) pneumoperitoneum. We further demonstrated that the postoperative immunosuppression is related to the length of the incision. Other investigators believe that the immunosuppression observed after laparotomy is caused by peritoneal exposure to small amounts of lipopolysaccharide found in circulating air. They believe that the better-preserved immune function associated with laparoscopic surgery results from the avoidance of air contamination of the peritoneal cavity. To investigate this hypothesis, we determined and compared postoperative lymphocyte proliferation rates after (a) laparotomy in room air, (b) laparotomy in a CO2 chamber, (c) CO2 insufflation in a murine model, and (d) anesthesia alone. METHODS: Female C3H/He mice (n = 21) were divided randomly into four groups: (a) anesthesia control, (b) air laparotomy, (c) CO2 laparotomy, and (d) CO2 insufflation. The control mice underwent no procedure. The group 2 animals underwent a full midline incision (xiphoid to pubis) and exposure to room air for 20 min and then were clipped closed. The group 3 mice underwent a full midline incision in a sealed CO2 chamber for 20 min, and the group 4 mice insufflation with CO2 gas at 4 to 6 mm Hg for 20 min. Splenocytes were harvested from all the animals on day 2 after the interventions. Lymphocyte proliferation then was assessed using the nonradioactive colorimetric MTS/PMS system 72 h after concanavalin-A stimulation. RESULTS: There was no significant difference in lymphocyte proliferation between the air and CO2 laparotomy groups. Lymphocyte proliferation in the anesthesia control and CO2 insufflation groups was significantly higher than in both the air laparotomy (p<0.05) and CO2 laparotomy (p<0.05) groups (p values by Tukey-Kramer test). There was no significant difference between the anesthesia control and CO2 pneumoperitoneum groups. CONCLUSIONS: Our results suggest that full laparotomy performed in a sealed CO2 chamber compared to room air laparotomy resulted in similar suppression of lymphocyte proliferation. Furthermore, no significant suppression of lymphocyte proliferation was observed in the CO2 pneumoperitoneum group. These results, with regard to lymphocyte proliferation rates, refute the hypothesis that postoperative immunosuppression is related to air exposure and support the alternative hypothesis that immunosuppression is related to incision length.

Air↗

PubMed2000

Port site tumor recurrence rates in a murine model of laparoscopic splenectomy decreased with increased experience.

BACKGROUND: The etiology of port site tumor recurrences following laparoscopic surgery for cancer remains unknown. A recent study from our laboratory using a murine splenic tumor model suggests that it is poor surgical technique (i.e., crushing of the tumor) rather than the CO2 pneumoperitoneum that is responsible for these tumors. However, in that experiment, no intraabdominal procedure was carried out. We subsequently performed a preliminary study in which we compared the rate of port site tumor recurrences after laparoscopic-assisted splenectomy (LAS) vs open splenectomy (OS) using the murine splenic tumor model. In this study, we found significantly more port and incisional tumors after laparoscopic splenectomy. The reasons for this finding are unclear. Further analysis of the data showed that the incidence of port tumors in the LAS group decreased dramatically from the first to the second trial, suggesting that the experience of the surgeon may play a role. The purpose of the current study was to carry out further trials to determine if the lower rate of port tumor recurrence in the laparoscopic group will persist with increased surgical experience. METHODS: Splenic tumors were established in female Balb/C mice (n = 128) via a subcapsular injection of a 0.1-cc suspension containing 10(5) C-26 colon adenocarcinoma cells via a left flank incision at the initial procedure. Seven days later, the animals with isolated splenic tumors (95%) were randomized to one of two groups-open splenectomy (OS) or laparoscopic-assisted splenectomy (LAS). Three ports were placed in similar locations in all animals. The OS mice underwent an open splenectomy via a subcostal incision and anesthesia for 20 min. The LAS mice underwent laparoscopic mobilization of the spleen using a three-port technique, followed by an extracorporeal splenectomy via a subcostal incision. Seven days after splenectomy, the mice were killed and inspected for abdominal wall tumor implants. The experiment was carried out in four separate trials. RESULTS: When the results of the four trials were combined, there was no significant difference in the incidence of animals with at least one port tumor recurrence between the OS vs the LAS group (25% vs 35.2%; p = 0.30, power = 0.91). However, the overall incidence of port site tumors (number of ports with tumors/total number of ports for each group) was significantly higher in the laparoscopic-assisted group than in the open group (18.5% vs 9.5%; p = 0.03). It was noted that the incidence of port tumor recurrence (PTR) in the LAS group dropped significantly from the first to the latter three trials (second, third, and fourth trials combined) (36.1% vs 13.5%; p < 0.006) while it did not change significantly in the OS group. In the latter three trials, there was no significant difference in the number of animals with PTR between the LAS and the OS group (13.5% vs 9.8%; p = 0.43). CONCLUSIONS: Overall, there was no significant difference between the OS and the LAS groups in number of animals with port tumor recurrence or subcostal wound tumor recurrence. However, there were more port tumors in the laparoscopic-assisted group. The reasons for these findings are unclear. The laparoscopic mobilization was quite difficult; it required excessive splenic manipulation, which may have liberated tumor cells from the primary lesion and facilitated port tumor formation. With increased experience, less manipulation was required to complete the mobilization. Of note, the incidence of port tumors in the LAS group decreased significantly from the first to the subsequent three trials; therefore, it is possible that surgical technique is a factor in port tumor formation. The CO2 pneumoperitoneum may also be a factor, but this seems less likely.

Abdominal Neoplasms↗

PubMed2000

A serum-soluble factor(s) stimulates tumor growth following laparotomy in a murine model.

BACKGROUND: Our laboratory and others have previously demonstrated that tumors grow larger and are more easily established following laparotomy than after CO(2) pneumoperitoneum. The etiology of increased tumor growth after surgery is unknown. We hypothesized that, following laparotomy, a serum soluble factor(s) is generated that causes tumors to proliferate more rapidly. The purpose of the current study was to determine if in vitro tumor cells proliferate faster when incubated with serum from laparotomized mice than cells incubated with sera from mice who have undergone CO(2) pneumoperitoneum or anesthesia alone. METHODS: In the first experiment, female Balb/C mice (n = 84) were randomly divided into the following three groups: (a) control (AC), (b) CO(2) insufflation (INS), and (c) laparotomy (OPEN). The AC mice underwent no procedure. The INS group underwent CO(2) pneumoperitoneum at 4-6 mmHg for 20 min. The OPEN group had a midline incision from xiphoid to pubis. The serum of seven mice from each group were collected on postoperative days (POD) 1, 2, 4, and 7 via a cardiac puncture. The sera at each time point for each group were pooled. Twenty thousand C-26 colon cancer cells were incubated separately in growth media containing 10% mouse serum from each group (seven determinations/group) at each time point. In the second experiment, female Balb/C (n = 30) mice were divided into AC and OPEN groups. On POD4, sera were collected and pooled. Three separate studies were performed for the second experiment. In the first study, tumor cells were incubated with 10% AC sera or varying concentrations of OPEN mice sera (4-10%). In the second study, aliquots of sera from the OPEN group mice were then heated at 100 degrees C for 1 or 5 min. Tumors were then incubated separately in media with 10% AC, OPEN, or heated OPEN group sera. In the third study, aliquots of sera from the OPEN group mice were dialyzed against PBS through a 3.5-kD or an 8-kD dialysis membrane tubing for 24 h. Tumors were then incubated separately in media with 10% AC, OPEN, or dialyzed OPEN group sera. For both experiments, tumor proliferation was determined and compared between groups after 72 h of incubation. RESULTS: Tumor cells incubated with POD2 and POD4 sera from OPEN group mice proliferated twice as fast as those incubated with sera from either AC or INS group mice. The difference in proliferation was maximal on POD4 and started to decline by POD7. Proliferative activity from the OPEN group sera decreased significantly when heated for 1 min and was completely ablated after 5 min of heating. Proliferative activity from the OPEN group sera was completely ablated after dialysis. CONCLUSIONS: We conclude that there is a serum-soluble factor(s) present postoperatively that stimulates tumors to grow significantly faster after laparotomy. The mitogenic effect of laparotomized mice sera is dilutable. It is uncertain whether the factor is heat labile, since heating most likely destroys other necessary proteins in the sera. The size of the factor is undeterminable using the dialysis method. Further efforts to identify these factors are currently underway.

Animals↗

PubMed2000

Time course of differences in lymphocyte proliferation rates after laparotomy vs CO(2) insufflation.

BACKGROUND: Our laboratory has previously demonstrated that cell-mediated immune function is significantly more suppressed after both laparotomy and laparoscopic-assisted bowel resection than after peritoneal insufflation or open bowel resection, as assessed by delayed-type hypersensitivity (DTH) response. The purpose of this study was to further evaluate cell-mediated immunity by examining lymphocyte proliferation rates after laparotomy vs CO(2) insufflation. METHODS: Female Balb/C mice (n = 75) were randomly divided into the following three groups: (a) anesthesia control (A/C), (b) CO(2) insufflation (INS), and (c) sham laparotomy (OPEN). The A/C group mice underwent no procedure. The INS group underwent insufflation with CO(2) gas at 4-6 mmHg for 20 min. The OPEN group underwent a midline incision from xiphoid to pubic symphysis, which was clipped closed after 20 min. Splenocytes were obtained via splenic harvest and lymphocyte isolation on postoperative days (POD) 1, 2, 3, 4, and 8. Lymphocyte proliferation was determined by a nonradioactive colorimetric MTS/PMS assay 72 h after concanavalin A stimulation. RESULTS: The laparotomy group's lymphocyte proliferation rates were significantly lower than both the control and the insufflation groups on POD 2, POD 3, and POD 4. On POD 1 and POD 8, there were no significant differences in lymphocyte proliferation among the three groups. No differences were found between the control and insufflation groups at any point. CONCLUSIONS: After stimulation, lymphocytes proliferate at a lower rate after laparotomy than after CO(2) insufflation. Significant differences in lymphocyte proliferation rates between groups persist at least through POD 4. By POD 8, the mean lymphocyte proliferation rate in the laparotomy group was back to the baseline level. Our results suggest greater immunosuppression after sham laparotomy than after CO(2) insufflation.

Animals↗

PubMed2000

A technique of stapled gastrojejunostomy for open gastric bypass results in increased wound complication-rate.

BACKGROUND: Gastric bypass may be facilitated by a stapled gastrojejunostomy. This study compared two different techniques for performing this critical anastomosis in open surgery. METHODS: 67 consecutive patients were retrospectively studied for weight loss, hospital length of stay, anastomotic stricture, wound complication, and incisional hernia. 49 patients had a two layer hand-sutured gastrojejunostomy over a 34 Fr bougie via a laparotomy (sutured). 18 patients had a stapled gastrojejunostomy using the technique of Wittgrove and Clark via a laparotomy (stapled). All patients received prophylactic intravenous antibiotics preoperatively. RESULTS: Initial BMI, % of excess weight lost at 6 weeks and 6 months, and hospital length of stay were not statistically different between the groups. However, the rate of wound complication and incisional hernia rate were significantly higher in the stapled group when compared to the sutured group (p< 0.01). CONCLUSIONS: Based on these data we suggest that the technique of Wittgrove and Clark for performing the gastrojejunostomy should not be used in open gastric bypass as it results in increased rates of wound complication and incisional hernia.

Adult↗

PubMed1999

Increased sensitivity to complement and a decreased red blood cell life span in mice mosaic for a nonfunctional Piga gene.

The gene PIGA encodes one of the protein subunits of the alpha1-6-N acetylglucosaminyltransferase complex, which catalyses an early step in the biosynthesis of glycosyl phosphatidylinositol (GPI) anchors. PIGA is somatically mutated in blood cells from patients with paroxysmal nocturnal hemoglobinuria (PNH), leading to deficiency of GPI-linked proteins on the cell surface. To investigate in detail how inactivating mutations of the PIGA gene affect hematopoiesis, we generated a mouse line, in which loxP-mediated excision of part of exon 2 occurs on the expression of Cre. After crossbreeding with EIIa-cre transgenic mice, recombination occurs early in embryonic life. Mice that are mosaics for the recombined Piga gene are viable and lack GPI-linked proteins on a proportion of circulating blood cells. This resembles the coexistence of normal cells and PNH cells in patients with an established PNH clone. PIGA(-) blood cells in mosaic mice have biologic features characteristic of those classically seen in patients with PNH, including an increased sensitivity toward complement mediated lysis and a decreased life span in circulation. However, during the 12-month follow-up, the PIGA(-) cell population did not increase, clearly showing that a Piga gene mutation is not sufficient to cause the human disease, PNH.

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