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Biomedical subjects

R J Bold

Publications and source records attributed to R J Bold.

At least 19 recordsLinked to original sources
PubMed2000

Laparoscopic suturing evaluation among surgical residents.

BACKGROUND: Laparoscopic suturing is an integral part of advanced laparoscopic surgery training. The objective of this study was to evaluate the performance and preference of surgical residents performing intracorporeal and extracorporeal knot-tying techniques using conventional and Endo Stitch instruments. The residents were also evaluated on their suturing techniques using conventional instruments, the Endo Stitch, and the Suture Assistant. METHODS: Using an inanimate laparoscopic trainer model, 39 residents were evaluated as they performed laparoscopic knot tying exercises. Endpoints of the study were execution time and subjective preference of surgical residents with respect to the type of instrument used for knot tying. Forty-three residents were evaluated as they performed laparoscopic suturing exercises with three different types of suturing instruments using the same endpoints. RESULTS: The intracorporeal technique was the preferred (89%) method of knot tying among surgical residents. The time for completion of laparoscopic suturing was significantly (P < 0.05) shorter with the Endo Stitch (114 +/- 64 s) than with the conventional instrument (206 +/- 107 s) or the Suture Assistant (151 +/- 70 s). Residents preferred the use of the Endo Stitch in all three categories for suturing, knot tying, and handling. CONCLUSION: The Endo Stitch enhanced laparoscopic skills and was the preferred instrument for laparoscopic knot tying and suturing among surgical residents.

Humans↗
PubMed1999

Patterns of recurrence in extremity liposarcoma: implications for staging and follow-up.

BACKGROUND: Liposarcoma is one of the most common histologic types of soft tissue sarcoma and presents a wide spectrum of clinical behavior. The authors examined the correlation among histologic subtypes, outcomes, and patterns of recurrence among patients with extremity liposarcomas. METHODS. A retrospective review of all patients with intermediate and high grade extremity liposarcoma referred to the University of Texas M. D. Anderson Cancer Center from January 1, 1980, to December 31, 1992, was performed. Data on clinical presentation, treatment, patterns of treatment failure, and outcome were evaluated. RESULTS: During the 13-year study period, 122 patients with intermediate or high grade extremity liposarcoma were identified: 102 patients (84%) with myxoid subtype, 18 patients (15%) with pleomorphic subtype, and 2 patients (2%) with mixed histology. There were no differences between the myxoid and pleomorphic subtype groups in tumor size (T1 vs. T2), depth in relation to the muscular fascia, or anatomic site. The median follow-up was 70 months. The 5-year overall survival rate for all intermediate and high grade extremity liposarcoma patients presenting with primary disease (n=85) was 74%; the 5-year local recurrence free survival, distant recurrence free survival, and disease free survival rates were 93%, 78%, and 73%, respectively. Among the 102 patients with myxoid tumors, 33 had distant recurrences; 31 of these were to extrapulmonary soft tissue sites (e.g., the retroperitoneum, chest wall, pleura, pericardium, pelvic sidewall, and soft tissue of the back), and 2 were to the lung only. Among the 18 patients with pleomorphic tumors, 10 had distant recurrences; 3 occurred at extrapulmonary sites, and 7 occurred in the lung only (P < 0.05 for myxoid vs. pleomorphic subtypes). CONCLUSIONS: Myxoid liposarcomas often metastasized to extrapulmonary sites and did so significantly more frequently than pleomorphic tumors. Imaging of the abdomen, retroperitoneum, and extrapleural chest should be performed for accurate staging and posttreatment follow-up of patients with myxoid liposarcoma. Patients presenting with "primary" myxoid liposarcoma of the trunk should be carefully evaluated for an occult primary tumor in an extremity.

Adolescent↗
PubMed1998

Prospective, randomized trial of Doppler-assisted subclavian vein catheterization.

OBJECTIVE: To examine the rate of success and complications of Doppler-guided subclavian vein catheter insertion compared with standard insertion in patients considered at high risk for failure. DESIGN: Prospective, randomized, crossover trial. SETTING: University-affiliated tertiary care medical center. PATIENTS: Two hundred forty patients were enrolled in the study. Patients were stratified for 3 known risk factors: (1) prior surgery in the subclavian vein region, (2) prior radiotherapy at the attempted catheterization site, and (3) an abnormal weight-height ratio. INTERVENTIONS: Subclavian vein catheterization was performed either in standard or Doppler-guided fashion using the Smart Needle (Peripheral Systems Group, Mountain View, Calif), which is a Doppler probe at the tip of a cannulating needle. If subclavian vein catheterization was unsuccessful after 2 attempts, patients were crossed over to the other technique. MAIN OUTCOME MEASURE: Successful cannulation of the subclavian vein. RESULTS: The success rate, either as an initial technique or as a salvage technique, and complication rate were not significantly different with use of the Smart Needle. A subgroup of physicians had a significantly lower success rate using the Smart Needle. CONCLUSIONS: Doppler guidance did not increase the success rate or decrease the complication rate of subclavian vein catheterization when compared with the standard technique in high-risk patients. Doppler guidance was not more useful than the standard technique as a salvage technique following a previous failure of catheterization. Furthermore, real-time Doppler guidance of subclavian vein catheterization is a technique that is highly operator dependent.

Adolescent↗
PubMed1998

Adenovirus-mediated wild-type p53 tumor suppressor gene therapy induces apoptosis and suppresses growth of human pancreatic cancer [seecomments].

BACKGROUND: The p53 tumor suppressor gene is mutated in up to 70% of pancreatic adenocarcinomas. We determined the effect of reintroduction of the wild-type p53 gene on proliferation and apoptosis in human pancreatic cancer cells using an adenoviral vector containing the wild-type p53 tumor suppressor gene. METHODS: Transduction efficiencies of six p53-mutant pancreatic cancer cell lines (AsPC-1, BxPC-3, Capan-1, CFPAC-1, MIA PaCa-2, and PANC-1) were determined using the reporter gene construct Ad5/CMV/beta-gal. Cell proliferation was monitored using a 3H-thymidine incorporation assay, Western blot analysis for p53 expression was performed, and DNA laddering and fluorescence-activated cell sorter analysis were used to assess apoptosis. p53 gene therapy was tested in vivo in a subcutaneous tumor model. RESULTS: The cell lines varied in transduction efficiency. The MIA PaCa-2 cells had the highest transduction efficiency, with 65% of pancreatic tumor cells staining positive for beta-galactosidase (beta-gal) at a multiplicity of infection (MOI) of 50. At the same MOI, only 15% of the CFPAC-1 cells expressed the beta-gal gene. Adenovirus-mediated p53 gene transfer suppressed growth of all human pancreatic cancer cell lines in a dose-dependent manner. Western blot analysis confirmed the presence of the p53 protein product at 48 hours after infection. DNA ladders demonstrated increased chromatin degradation, and fluorescence-activated cell sorter analysis demonstrated a four-fold increase in apoptotic cells at 48 and 72 hours following infection with Ad5/CMV/p53 in the MIA PaCa-2 and PANC-1 cells. Suppression of tumor growth mediated by induction of apoptosis was observed in vivo in an established nude mouse subcutaneous tumor model following intratumoral injections of Ad5/CMV/p53. CONCLUSIONS: Introduction of the wild-type p53 gene using an adenoviral vector in pancreatic cancer with p53 mutations induces apoptosis and inhibits cell growth. These data provide preliminary support for adenoviral mediated p53 tumor suppressor gene therapy of human pancreatic cancer.

Adenocarcinoma↗
PubMed1998

Preoperative chemoradiation strategies for localized adenocarcinoma of the pancreas.

Patients who undergo pancreaticoduodenectomy alone for adenocarcinoma of the pancreatic head or uncinate process have a median survival of 12 months, and a high incidence of local tumor recurrence (50%-80%) due to the common finding of positive margins following pathologic evaluation of pancreaticoduodenectomy specimens. The available prospective and retrospective data suggest improved survival duration and local-regional tumor control when pancreaticoduodenectomy is combined with 5-FU-based chemoradiation. However, the morbidity and prolonged recovery associated with pancreaticoduodenectomy frequently prevent the timely delivery of postoperative chemoradiation. In contrast, chemoradiation delivered prior to pancreaticoduodenectomy is not associated with toxic effects which delay surgery and has not been shown to increase surgical morbidity or mortality. In fact, recent data suggest that pancreaticojejunal anastomotic leaks, the most common major complication following pancreaticoduodenectomy, are decreased in patients who receive preoperative radiation therapy. Current and future multimodality treatment strategies will capitalize on our expanding understanding of tumor growth and metastasis, allowing more effective radiation sensitizing agents to be combined with external-beam irradiation and surgery, followed by the systemic or regional delivery of novel agents that inhibit essential steps in tumor cell growth.

Adenocarcinoma↗
PubMed1998

Prospective, randomized, double-blind study of prophylactic antibiotics in axillary lymph node dissection.

BACKGROUND: Antibiotic prophylaxis is controversial in patients undergoing axillary lymph node dissection (ALND). We determined whether preoperative antibiotics decreased incidence or treatment cost of infectious complications following ALND. METHODS: Two hundred patients entered this prospective, randomized, double-blind trial. Patients received either placebo or cefonicid preoperatively. Loco-regional signs of infection were monitored for 4 weeks postoperatively. RESULTS: There was a trend toward fewer infections in the prophylactic group (placebo 13% versus cefonicid 6%; P = 0.080). Cefonicid significantly decreased severe infections requiring hospitalization (placebo 8% versus cefonicid 1%; P = 0.033). Cefonicid also decreased the treatment cost of infection per patient ($49.80 versus $364.87). CONCLUSIONS: We demonstrated a trend toward fewer overall infections and significantly fewer severe infections in patients given prophylactic antibiotics, which translated into a decrease in the cost of treatment for infectious complications. These findings support antibiotic prophylaxis for patients undergoing ALND.

Adult↗
PubMed1998

A human gastric cancer cell line possesses a functional receptor for gastrin-releasing peptide.

Bombesin (BBS) exhibits diverse biological functions including those of neurotransmitter, regulator of gastrointestinal hormone release, and mitogen. Gastrin-releasing peptide (GRP, the mammalian equivalent of BBS) is found in mucosal cells of the gastric fundus and antrum. We determined whether a human gastric cancer cell line (SIIA) expresses a functional GRP-receptor (GRP-R). BBS increased intracellular calcium ([Ca2+]i), and a specific GRP-R antagonist, ([D-Phe6, Des-Met14]-BBS (6-14)-ethylamide), blocked BBS-induced increase in [Ca2+]i. SIIA cells possess GRP-R mRNA by reverse transcriptase-PCR. Furthermore, these cells possess an 80-kDa cell surface protein that specifically binds BBS with two high-binding affinities (Kd1 = 0.6 nM, Kd2 = 6.7 nM). These findings indicate that SIIA cells possess a GRP-R that is capable of physiological signal transduction, though the cellular response remains unknown.

Adenocarcinoma↗
PubMed1997

Apoptosis, cancer and cancer therapy.

Apoptosis is a specific process that leads to programmed cell death through the activation of an evolutionary conserved intracellular pathway leading to pathognomic cellular changes distinct from cellular necrosis. Apoptosis is essential in the homeostasis of normal tissues of the body, especially those of the gastrointestinal tract, immune system and skin. There is increasing evidence that the processes of neoplastic transformation, progression and metastasis involve alterations in the normal apoptotic pathways. Furthermore, the majority of chemotherapeutic agents as well as radiation utilize the apoptotic pathway to induce cancer cell death. Resistance to standard chemotherapies also seems to be determined by alterations in the apoptotic pathways of cancer cells. Therefore, understanding the signals of apoptosis and the mechanism of apoptosis may allow the development of better chemo- or radiotherapeutic regimens for the treatment of cancer. Finally, components of the apoptotic pathway may represent potential therapeutic targets using gene therapy techniques.

Animals↗
PubMed1996

Surgery.

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Bacterial Translocation↗
PubMed1996

Hyperphosphorylation of retinoblastoma protein and stimulation of growth by okadaic acid in human pancreatic cancer.

Phosphorylation/dephosphorylation of intracellular proteins are important steps in the regulation of cell growth. Okadaic acid, an inhibitor of the serine/threonine protein phosphatases 1 and 2A, is a potent tumor promoter. This effect may be through the inhibition of dephosphorylation (termed "hyperphosphorylation") and subsequent inactivation of tumor-suppressor proteins. We examined whether okadaic acid regulates growth of human pancreatic cancer cells (MIA PaCa-2 and Panc-1) or alters the phosphorylation of the retinoblastoma tumor-suppressor protein. Growth studies, nuclear labeling analyses, and Western blotting for retinoblastoma protein were performed. Okadaic acid stimulated cell growth and induced hyperphosphorylation of the retinoblastoma protein. The growth-stimulatory effect of okadaic acid on these human pancreatic cancer cells may be mediated by inactivation of the growth suppressive effect of the retinoblastoma protein by hyperphosphorylation. These studies suggest that the growth of these human pancreatic cancer cells is still regulated by tumor-suppressor proteins.

Blotting, Western↗
PubMed1996

Progress toward hormonal therapy of gastrointestinal cancer.

OBJECTIVE: The authors discuss ongoing research to determine the mechanisms by which peptide hormones regulate growth of gastrointestinal cancer and ways in which this information might be used to develop noncytotoxic therapy. SUMMARY BACKGROUND: Approximately 100,000 people die of cancer of the gastrointestinal (GI) tract each year. Surgery is curative only when the tumor is localized. Chemotherapy and radiotherapy have limited efficacy for locally advanced or widespread disease. Various peptide hormones regulate the growth of these tumors. As for breast and prostate cancer, the growth regulatory effect of these hormones is being studied as a potential mechanism of hormonal therapy. CONCLUSION: Gut peptide hormones regulate the growth of GI malignancies through all-specific receptors and signal transduction pathways. Interruption or modification of these growth regulatory mechanisms may lead to specific noncytotoxic therapy. In combination with surgical extirpation, such hormonally based treatment may be curative of advanced GI cancer.

Animals↗
PubMed1996

All-trans-retinoic acid inhibits growth of human pancreatic cancer cell lines.

Retinoids are a class of molecules structurally related to vitamin A that have potent antiproliferative and differentiating effects on a variety of normal and neoplastic tissues. All-trans-retinoic acid (ATRA) has become a first-line chemotherapeutic agent in the treatment of certain leukemias; however, the effect of ATRA on pancreatic tumors is unknown. The purpose of this study was to determine the effect of ATRA on the growth characteristics of both exocrine and endocrine human pancreatic cancer cell lines. The in vitro growth of four cell lines was examined after treatment with a wide dose range of ATRA. The growth of all tumor cell lines was inhibited by ATRA in a dose-dependent fashion beginning at 0.1 microgram M. The in vivo growth of functioning human pancreatic carcinoid (BON) xenografts in Balb/c athymic mice was determined by treatment with several doses of ATRA over 1 month. The growth of BON tumors was inhibited in a dose-dependent fashion. These results suggest that ATRA exerts direct antiproliferative effects on both exocrine and endocrine human pancreatic cancers and may be useful in the chemotherapy of these tumors.

Animals↗
PubMed1996

Human monoclonal antibody against colon cancer.

The purpose of the study was to produce human monoclonal antibodies (hMcAb) against human colon cancer for use in radioimmunoimaging. Human-mouse heterohybridomas were developed by fusing SHM-D33 mouse-human hybrid heteromyeloma cells with human lymphocytes from colon cancer tumor-draining lymph nodes. The hybridomas capable of secreting human monoclonal antibodies were screened by using human colon cancer cell lines and pathological biopsies with ELISA and immunohistochemical methods. hMcAb clone H11 was selected for a large-scale antibody production, which was purified from mouse ascites. Biodistribution study demonstrated that specific uptake of 125I-hMcAb H11 by human colon cancer xenografts was significantly higher than by normal tissues. Radioimmunoimaging of human colon cancer xenografts exhibited distinct tumor visualization during the period of 72-96 hr after intraperitoneal injection of 125I-hMcAb H11. The development of human monoclonal antibodies such as hMcAb H11 may be useful for radioimmunodetection and therapy of colon cancer.

Animals↗
PubMed1995

Growth of mouse hepatocytes is stimulated by gastrin.

Hepatocyte growth is regulated by various growth factors, including epidermal growth factor (EGF) and insulin. Recently, several additional peptide hormones have been shown to stimulate growth of hepatocyte only in the presence of EGF or insulin and are thus termed secondary mitogens. Gastrin regulates growth of normal and neoplastic gastrointestinal tissues, but the effect on growth of hepatocyte is unknown. We examined the effect of gastrin on growth of a normal mouse hepatocyte (NMH) line established in our laboratory. Effect of gastrin-17 (G-17) (10(-8) to 10(-6) M) on growth of NHM cells was examined in either the presence or absence of EGF in the culture medium. Growth of NMH cells was evaluated by incorporation of either bromodeoxyuridine (BrdU) or 3H-thymidine and by counting cells. Presence of a cell-surface receptor for G-17 was determined by Scatchard analysis using 125I-G-17. In the presence of EGF, gastrin stimulated growth of NMH cells; in the absence of EGF, gastrin did not affect growth. The stimulatory effect of gastrin on NMH cells was blocked by JMV 320, a CCK-B type receptor antagonist. NMH cells possess a single, high affinity binding site for gastrin (Kd = 1.2 nM); EGF increased the gastrin binding capacity compared to non-treated cells (3.5 +/- 0.4 vs. 2.2 +/- 0.6 fmol/10(6) cells). G-17 stimulated growth of NMH cells through a single high affinity receptor for G-17 which pharmcologically appears to be the CCK-B type only in the presence of EGF and thus can be considered a secondary mitogen.

Animals↗
PubMed1995

Secretin potentiates cholecystokinin-stimulated amylase release by AR4-2J cells via a stimulation of phospholipase C.

Alterations in the activity of phospholipase C (PLC) are thought to be the primary intracellular events leading to pancreatic acinar cell exocytosis of zymogen granules. When multiple hormones, each of which may stimulate different signal transduction pathways, bind to cell surface receptors, the cell must integrate these signals into a common response through communication (cross-talk) among intracellular second messengers. We show that cholecystokinin (CCK) induces amylase secretion from AR4-2J pancreatic acinar cells via stimulation of PLC activity. Secretin indirectly stimulated the PLC pathway through cross-talk of the activated cAMP pathway to potentiate the CCK-stimulated amylase secretion. Therefore, secretin potentiated the acinar cell secretory response to CCK by cAMP-mediated cross-talk with the PLC signal transduction pathway.

Amylases↗
PubMed1995

Nerve growth factor as a mitogen for a pancreatic carcinoid cell line.

Carcinoid tumors are a group of neuroendocrine neoplasms distributed widely throughout the body but most commonly occurring in the gut. These tumors retain many characteristics of their neural crest origin, including secretion of neuroactive peptides and responsiveness to neurotrophic substances. Nerve growth factor (NGF), a neurotrophic protein involved in maintenance and differentiation of peripheral sympathetic and sensory neurons, regulates growth of several neural tumor cells by inducing a differentiated phenotype and subsequent inhibition of cell growth rate. We examined the actions of NGF in a functioning human pancreatic carcinoid cell line (termed BON). NGF has no effect on the cytoarchitecture or constitutive secretion of bioamines in this carcinoid cell line. NGF, however, stimulates the in vitro cellular proliferation of BON cells. BON cells possess mRNA for the NGF receptors (p75LNGFR and p140trkA) and membrane-associated tyrosine kinase activity is increased in response to NGF. Both the mitogenic activity of NGF, as well as the receptor-linked tyrosine kinase activity, can be abrogated in BON cells by the trkA inhibitor K-252a and specific anti-NGF antibody. Our studies demonstrate that NGF is a mitogen for this carcinoid cell line without effect on cellular phenotype or cytoarchitecture. NGF may play a role in the development and progression of human carcinoid tumors.

Carbazoles↗