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Biomedical subjects

Larry R Kaiser

Publications and source records attributed to Larry R Kaiser.

At least 37 records · Page 2Linked to original sources
PubMed2005

Treatment of lung cancer using clinically relevant oral doses of the cyclooxygenase-2 inhibitor rofecoxib: potential value as adjuvant therapy after surgery.

OBJECTIVE: To investigate the uses and limitations of cyclooxygenase- (COX) 2 inhibition using clinically relevant doses of oral rofecoxib in the treatment of murine models of non-small-cell lung cancer (NSCLC). SUMMARY BACKGROUND DATA: Overexpression of COX-2 has been reported in lung cancer. Several studies have demonstrated that high doses of COX-2 inhibitors could inhibit the growth of rodent and human lung cancer cell lines. The potential uses and limitations of COX-2 inhibition at doses equivalent to those currently approved for use in humans have not been well studied. METHODS: Three murine NSCLC cell lines were injected into the flanks of mice to establish tumor xenografts. Mice were treated orally with low doses of a COX-2 inhibitor (rofecoxib chow, 0.0075%). Mechanisms were evaluated by analysis of tumor-infiltrating lymphocytes. To study rofecoxib as adjuvant therapy, large established tumors (14-18 days after tumor inoculation) were surgically debulked and animals were treated with rofecoxib starting 3 days before surgery. Recurrence of the tumor after debulking was monitored. RESULTS: Rofecoxib significantly slowed the growth of small (0-120 mm) tumors (P < 0.01-0.05) in all 3 cell lines, with higher efficacy in the more immunogenic tumors. Minimal responses were noted in larger tumors. Rofecoxib appeared to augment CD8 T cell infiltration in immunogenic tumors. Rofecoxib significantly reduced the recurrence rate after debulking (P < 0.01). CONCLUSIONS: Clinically relevant doses of the COX-2 inhibitor rofecoxib given orally were effective in inhibiting the growth of small (but not large) tumors in 3 murine NSCLC cell lines tested and in preventing recurrences after surgical debulking. Depending on the immunogenicity of human tumors, COX-2 inhibition might be useful as adjuvant therapy for surgically resectable NSCLC.

Administration, Oral↗
PubMed2005

Surgeon contribution to hospital bottom line: not all are created equal.

OBJECTIVE: We hypothesized that surgeon productivity is directly related to hospital operating margin, but significant variation in margin contribution exists between specialties. SUMMARY BACKGROUND DATA: As the independent practitioner becomes an endangered species, it is critical to better understand the surgeon's importance to a hospital's bottom line. An appreciation of surgeon contribution to hospital profitability may prove useful in negotiations relating to full-time employment or other models. METHODS: Surgeon total relative value units (RVUs), a measure of productivity, were collected from operating room (OR) logs. Annual hospital margin per specialty was provided by hospital finance. Hospital margin data were normalized by dividing by a constant such that the highest relative hospital margin (RHM) in fiscal year 2004 expressed as margin units (mu) was 1 million mu. For each specialty, data analyzed included RHM/OR HR, RHM/case, and RHM/RVU. RESULTS: Thoracic (34.55 mu/RVU) and transplant (25.13 mu/RVU) were the biggest contributors to hospital margin. Plastics (-0.57 mu/RVU), maxillofacial (1.41 mu/RVU), and gynecology (1.66 mu/RVU) contributed least to hospital margin. Relative hospital margin per OR HR for transplant slightly exceeded thoracic (275.74 mu vs 233.94 mu) at the top and plastics and maxillofacial contributed the least (-3.83 mu/OR HR vs 9.36 mu/OR HR). CONCLUSIONS: Surgeons contribute significantly to hospital margin with certain specialties being more profitable than others. Payer mix, the penetration of managed care, and negotiated contracts as well as a number of other factors all have an impact on an individual hospital's margin. Surgeons should be fully cognizant of their significant influence in the marketplace.

Benchmarking↗
PubMed2005

Pain and physical function are similar following axillary, muscle-sparing vs posterolateral thoracotomy.

STUDY OBJECTIVES: We set out to determine whether there is a difference in postoperative pain and recovery after the patient undergoes the axillary muscle-sparing incision (ie, muscle-sparing thoracotomy [MT]) vs the modified posterolateral incision (ie, posterolateral thoracotomy [PT]). DESIGN: Analysis of a database originally collected to determine the effect of the timing of epidural analgesia on long-term outcome after thoracotomy. SETTING: The Hospital of the University of Pennsylvania. PATIENTS: Patients presenting for lobectomy, segmentectomy, or bilobectomy. MEASUREMENTS: Pain, physical activity, and the extent that pain interfered with activities following major thoracotomy were prospectively assessed with standard questionnaires (ie, the brief pain inventory and the Medical Outcomes Study 36-item short form) on postoperative days 1 to 5, and at postoperative weeks 4, 8, 12, 24, 36, and 48 by a blinded research assistant. Perioperative care was standardized and included patient-controlled thoracic epidural analgesia until thoracostomy tube removal. RESULTS: Eighty-two subjects underwent MT and 38 subjects underwent PT during the 16-month accrual period. There were no significant differences in demographics. Pain reported during hospitalization and after hospital discharge did not differ with respect to incision type (p > or = 0.17). Postoperative physical activity levels were significantly less than those reported preoperatively, with a trend toward better functioning in the MT groups after 8 weeks. Incision type did not predict complications, morbidity, or mortality. CONCLUSIONS: When comparing patients who had undergone vertical, axillary, wholly MT to those who had undergone modified serratus muscle-sparing PT, postoperative differences in pain were not apparent. One should not anticipate reduced pain or more rapid overall recovery following MT, at least when epidural analgesia is used aggressively for perioperative pain control.

Activities of Daily Living↗
PubMed2004

Soluble type II transforming growth factor-beta receptor inhibits established murine malignant mesothelioma tumor growth by augmenting host antitumor immunity.

PURPOSE: Transforming growth factor (TGF)-beta blockade has been proposed as an anticancer therapy; however, understanding which tumor patients might benefit most from such therapy is crucial. An ideal target of such inhibitory therapy might be malignant mesothelioma (MM), a highly lethal, treatment-resistant malignancy of mesothelial cells of the pleura and peritoneum that produces large amounts of TGF-beta. The purpose of this study was to explore the possible therapeutic utility of TGF-beta blockade on MM. EXPERIMENTAL DESIGN: To evaluate this hypothesis, we tested the effects of a soluble TGF-beta type II receptor (sTGF-beta R) that specifically inhibits TGF-beta1 and TGF-beta 3 in three different murine MM tumor models, AB12 and AC29 (which produce large amounts of TGF-beta) and AB1 (which does not produce TGF-beta). RESULTS: Tumor growth of both established AB12 and AC29 tumors was inhibited by sTGF-beta R. In contrast, AB1 tumors showed little response to sTGF-beta R. The mechanism of these antitumor effects was evaluated and determined to be primarily dependent on immune-mediated responses because (a) the antitumor effects were markedly diminished in severe combined immunodeficient mice or mice depleted of CD8(+) T cells and (b) CD8(+) T cells isolated from spleens of mice treated with sTGF-beta R showed strong antitumor cytolytic effects, whereas CD8(+) T cells isolated from spleens of tumor-bearing mice treated with of control IgG2a showed no antitumor cytolytic effects. CONCLUSIONS: Our data suggest that TGF-beta blockade of established TGF-beta-secreting MM should be explored as a promising strategy to treat patients with MM and other tumors that produce TGF-beta.

Animals↗
PubMed2004

Alterations of the tumor suppressor gene Parkin in non-small cell lung cancer.

PURPOSE: Parkin, a gene mutated in autosomal recessive juvenile Parkinsonism and mapped to the common fragile site FRA6E on human chromosome 6q25-q27, is associated with a frequent loss of heterozygosity and altered expression in breast and ovarian carcinomas. In addition, homozygous deletions of exon 2 creating deleterious truncations of the Parkin transcript were observed in the lung adenocarcinoma cell lines Calu-3 and H-1573, suggesting that the loss of this locus and the resulting changes in its expression are involved in the development of these tumors. EXPERIMENTAL DESIGN: We examined 20 paired normal and non-small cell lung cancer samples for the presence of Parkin alterations in the coding sequence and changes in gene expression. We also restored gene expression in the Parkin-deficient lung carcinoma cell line H460 by use of a recombinant lentivirus containing the wild-type Parkin cDNA. RESULTS: Loss of heterozygosity analysis identified a common region of loss in the Parkin/FRA6E locus with the highest frequency for the intragenic marker D6S1599 (45%), and semi-quantitative reverse transcription-PCR revealed reduced expression in 3 of 9 (33%) lung tumors. Although we did not observe any in vitro changes in cell proliferation or cell cycle, ectopic Parkin expression had the ability to reduce in vivo tumorigenicity in nude mice. CONCLUSION: These data suggest that Parkin is a tumor suppressor gene whose inactivation may play an important role in non-small cell lung cancer tumorigenesis.

Animals↗
PubMed2004

Lung cancer in transplant recipients: a single-institution experience.

HYPOTHESIS: That aggressive surgical treatment of lung cancer (LC) is justified by stage-based outcome in immunosuppressed solid organ transplant recipients. DESIGN: Case series. SETTING: University hospital. PATIENTS: Lung cancer developed in 15 patients (0.28%) among a solid organ transplant recipient population of 5400 accrued at our institution over a 25-year period. MAIN OUTCOME MEASURES: Smoking prevalence, subtypes and stages of LC represented, operative morbidity, and survival. RESULTS: The mean time from transplantation to the diagnosis of LC was 76 months (range, 9-192 months). Eight patients received kidneys; 3, lungs; and 4, hearts. Only 11 patients (73%) had a smoking history (mean, 66 pack-years). The following carcinomas developed in our patient population: adenocarcinoma, 6 patients; squamous cell, 5; large cell undifferentiated, 2; bronchoalveolar, 1; and small cell, 1. Eight patients (53%) presented with inoperable stage IIIB or IV disease. The remaining patients presented in stages IA (n = 2), IB (n = 1), IIB (n = 2), and IIIA (n = 2); all underwent resection. No major postoperative complications occurred. All patients with stage IIIB or greater disease with or without treatment died quickly (mean survival, 1.4 months; range, 0.33-3.0 months). All patients with stage IIB or less remain alive a mean of 37 months after resection. Patients with stage IIIA survived only a mean of 6.0 months despite resection. CONCLUSIONS: Regarding LCs in transplant recipients compared with LCs in the nontransplant population, we find that (1) there is an increased incidence among nonsmokers; (2) death occurs rapidly in unresected patients; (3) resection carries a low morbidity rate; and (4) resection seems to offer a high chance of cure in those with cancers staged IIB or less.

Adult↗
PubMed2004

Evolving options in the management of esophageal perforation.

Esophageal perforation remains a devastating event that is difficult to diagnose and manage. The majority of injuries are iatrogenic and the increasing use of endoscopic procedures can be expected to lead to an even higher incidence of esophageal perforation in coming years. Accurate diagnosis and effective treatment depend on early recognition of clinical features and accurate interpretation of diagnostic imaging. Outcome is determined by the cause and location of the injury, the presence of concomitant esophageal disease, and the interval between perforation and initiation of therapy. The overall mortality associated with esophageal perforation can approach 20%, and delay in treatment of more than 24 hours after perforation can result in a doubling of mortality. Surgical primary repair, with or without reinforcement, is the most successful treatment option in the management of esophageal perforation and reduces mortality by 50% to 70% compared with other interventional therapies.

Esophageal Perforation↗
PubMed2004

Two commonly used neoadjuvant chemoradiotherapy regimens for locally advanced stage III non-small cell lung carcinoma: long-term results and associations with pathologic response.

BACKGROUND: We performed this study to determine the outcomes (pathologic response, survival, local-regional control, and toxicity) in patients treated with neoadjuvant chemoradiotherapy and planned operation for stage IIIA non-small cell lung carcinoma. METHODS: Patients treated from 1993 to 2000 with neoadjuvant chemoradiotherapy and a predetermined plan for subsequent surgical resection for stage III non-small cell lung carcinoma were analyzed. All patients underwent pretreatment evaluation at the university's Multidisciplinary Lung Cancer Center. Most patients (87%) had complete mediastinoscopy staging, and all were believed to be poor candidates for up-front operation because of bulky extent of disease. The radiotherapy program used conventional, 2-dimensionally planned treatment to 45 to 54 Gy in 1.8- to 2-Gy fraction size. Concurrent chemotherapy consisted of etoposide/cisplatin or carboplatin/paclitaxel. Study end points included resectability, pathologic response, local-regional control, survival, and toxicity. An exploratory comparison between pathologic response and long-term survival was performed. An exploratory comparison between older chemotherapy (etoposide/cisplatin) and third-generation chemotherapy (carboplatin/paclitaxel) was also performed. RESULTS: Of 53 patients, 45 (85%) were deemed surgical candidates after induction therapy. Twenty-two (42% of the initial cohort) patients had a major pathologic response to stage 0, I, or II disease. The 5-year actuarial survival was 31%. Major pathologic response was associated with improved survival (48% vs 24%; P =.027). The overall rate of early death potentially related to therapy in this series was 9%; this mostly occurred in patients who underwent right pneumonectomy. There was no difference in efficacy or mortality between etoposide/cisplatin and radiotherapy versus carboplatin/paclitaxel and radiotherapy, although the latter regimen was associated with less grade 3 or higher acute toxicity necessitating interruption or hospitalization during neoadjuvant treatment (P =.02). In-field local control was achieved in 83% of all patients (90% of the patients who underwent resection). Brain metastases as the first site of treatment failure occurred in 23% of all patients. CONCLUSIONS: Neoadjuvant concurrent chemoradiation delivers high resectability, major pathologic response rate, and excellent local-regional control, with encouraging long-term survival considering the patient population studied. Major pathologic response correlates with long-term survival. Neoadjuvant carboplatin/paclitaxel and radiotherapy is an appropriate framework on which to add new therapies.

Aged↗
PubMed2004

Immuno-gene therapy with interferon-beta before surgical debulking delays recurrence and improves survival in a murine model of malignant mesothelioma.

OBJECTIVES: Immuno-gene therapy of mesothelioma with an adenovirus encoding interferon-beta mediated strong antitumor responses in murine models with low but not high tumor burden. Our goals were to determine the mechanisms responsible for this loss of efficacy and to test the hypothesis that the combination of preoperative adenovirus encoding interferon-beta and surgical resection would be effective in treating bulky tumors. METHODS: Flank tumors of a mouse mesothelioma cell line were treated with adenovirus encoding interferon-beta or adenoviral vector encoding the bacterial protein beta-galactosidase. Cytotoxic T lymphocytes and tumor infiltration by T lymphocytes were measured. Tumors were surgically excised 72 hours later and tumor cells were injected in the contralateral flank to create a model of a metastatic focus. Tumor-free survival and distant metastatic disease were assessed. RESULTS: Immuno-gene therapy effectively treated small tumors (<200 mm(3)) but did not reduce the size of large (>800 mm(3)) flank tumors. Although treatment with adenovirus encoding interferon-beta resulted in the generation of tumor-neutralizing splenocytes in large tumors, the number of T cells visualized within the tumors was minimal. Tumors treated with adenovirus encoding interferon-beta (versus adenoviral vector encoding the bacterial protein beta-galactosidase or phosphate-buffered saline solution) prior to debulking increased long-term tumor-free survival and resulted in two- to sixfold smaller foci of implanted tumor cells at 2 weeks postoperatively. CONCLUSIONS: The use of adenovirus encoding interferon-beta or surgical debulking alone is ineffective in treating large tumors, but combining preoperative adenovirus encoding interferon-beta and surgical debulking significantly reduces tumor recurrence and improves long-term tumor-free survival. We postulate that adenovirus encoding interferon-beta amplifies the cytotoxic T-lymphocyte antitumor response, allowing elimination of residual tumor cells.

Adenoviridae↗
PubMed2004

Simple technique for maximal thoracic muscle harvest.

We present a modification of technique for standard muscle flap harvest, the placement of cutaneous traction sutures. This technique allows for maximal dissection of the thoracic muscles even through minimal incisions. Through improved exposure and traction, complete dissection of the muscle bed can be performed and the tissue obtained maximized. Because more muscle bulk is obtained with this technique, the need for a second muscle may be prevented.

Humans↗
PubMed2003

Use of cyclooxygenase-2 inhibition to enhance the efficacy of immunotherapy.

Antitumor effects of cyclooxygenase-2 (COX-2) inhibition have been reported in a wide variety of tumor models and in human cancers, both as chemoprevention and therapy. Human mesothelioma tumors have been shown to overexpress COX-2 and high levels of COX-2 protein have been demonstrated to be a prognostic factor, indicating poor outcome in this tumor. In this study, we determined that inhibition of COX-2 by oral administration of Rofecoxib significantly slowed but did not cure the growth of small tumors in mesothelioma-bearing mice. Large tumors were unaffected. This effect was dependent on the presence of CD8+ T cells and was associated with increased tumor-infiltrating lymphocytes. Because these activities are consistent with a mechanism that results in a decrease in the immunosuppressive environment of the tumor, we additionally examined the effect of COX-2 blockade combined with Ad.IFN-beta therapy, a treatment that we have previously demonstrated results in expansion of antitumor CD8+ CTLs and cures a high percentage of small mesothelioma tumors in mice. Ad.IFN-beta therapy combined with COX-2 inhibition was associated with an increased number of T cells within tumors and resulted in cures of small tumors, significant inhibition of the growth of large established tumors, and inhibition of the growth of metastatic tumor foci after surgical debulking. The additive effects of these modes of treatment suggests that it would be rational to combine COX-2 inhibition with immuno- and immunogene therapy approaches (perhaps in conjunction with surgical debulking) in human clinical trials of treatment of mesothelioma and other tumors.

Adenoviridae↗
PubMed2003

Gene expression profiling of malignant mesothelioma.

PURPOSE: Malignant mesothelioma is a uniformly fatal cancer of the pleural and peritoneal spaces. Several challenging clinical problems include poor understanding of the pathophysiology, inaccurate diagnosis from tissue samples, and unsuccessful treatment strategies. The purpose of this study was to use microarray analysis to identify specific gene expression changes in mesothelioma compared with normal mesothelium. EXPERIMENTAL DESIGN: We performed gene expression analysis on mesothelioma tissue specimens from 16 patients and compared these to 4 control pleural tissue samples using cDNA microarray filters with 4132 clones. Multiple normalization and analysis approaches were used. Quantitative reverse transcription-PCR and immunohistochemistry were used to validate results. RESULTS: Genes (166) were significantly up-regulated, and 26 were down-regulated. Validation of 18 genes using real-time PCR confirmed array predictions in every case. Analysis revealed activation of several key pathways including genes involved in glucose metabolism, mRNA translation, and cytoskeletal remodeling. Expression profiling identified processes likely responsible for 18-fluoro-2-deoxy-glucose uptake and tumor localization by positron emission tomography, and a role for hypoxia-inducible factor-1 was suggested. Potentially important up-regulated genes included gp96, lung resistance-related protein, galectin-3 binding protein, the M(r) 67,000 laminin receptor (on tumor vessels), and voltage-dependent anion channels. Prospective testing using reverse transcription-PCR confirmed up-regulation of these novel markers. CONCLUSIONS: Expression profiling revealed marked up-regulation of energy, protein translation, and cytoskeletal remodeling pathways in mesothelioma. Additional genes that could be important in our understanding of the pathogenesis of mesothelioma, aiding in diagnosis, or improving targets for therapy were also identified.

Aged↗
PubMed2003

Human diaphragm remodeling associated with chronic obstructive pulmonary disease: clinical implications.

Diaphragm remodeling associated with chronic obstructive pulmonary disease (COPD) consists of a fast-to-slow fiber type transformation as well as adaptations within each fiber type. To try to explain disparate findings in the literature regarding the relationship between fiber type proportions and FEV1, we obtained costal diaphragm biopsies on 40 subjects whose FEV1 ranged from 118 to 16% of the predicted normal value. First, we noted that our exponential regression model indicated that changes in FEV1 can account for 72% of the variation in the proportion of Type I fibers. Second, to assess the impact of COPD on diaphragm force generation, we measured maximal specific force generated by single permeabilized fibers prepared from the diaphragms of two patients with normal pulmonary function tests and two patients with severe COPD. We noted that fibers prepared from the diaphragms of severe COPD patients generated a lower specific force than control fibers (p < 0.001) and Type I fibers generated a lower specific force than Type II fibers (p < 0.001). Our finding of an exponential relationship between the proportion of Type I fibers and FEV1 accounts for discrepancies in the literature. Moreover, our single-fiber results suggest that COPD-associated diaphragm remodeling decreases diaphragmatic force generation by adaptations within each fiber type as well as by fiber type transformations.

Adaptation, Physiological↗
PubMed2003

Allelic loss on chromosome 3p21.3 and promoter hypermethylation of semaphorin 3B in non-small cell lung cancer.

The aim of this study was to evaluate the promoter methylation status and loss of heterozygosity (LOH) of the SEMA3B in non-small cell lung cancers (NSCLCs). We analyzed the methylation status of semaphorin 3B (SEMA3B) promoter and LOH at 3p21.3 in eight NSCLC cell lines and 27 primary tumors. Hypermethylation of SEMA3B was found in 50% of the cell lines and 41% of the primary tumors studied. The presence of hypermethylation was statistically associated with loss of SEMA3B expression in both cell lines (P = 0.02) and primary tumors (P < 0.01). There was no correlation between SEMA3B and tumor stage. On the other hand, the correlation between SEMA3B methylation status and LOH at 3p21.3 was significant (P = 0.02). Notably, 7 of 8 tumors with both hypermethylation and LOH of SEMA3B showed the absence of the expression. Treatment with 5-AZAC restored SEMA3B expression in NSCLC cell line. These results indicate that SEMA3B gene alterations may play a important role in the malignant transformation of NSCLC via a two-hit mechanism, including epigenetic changes and allelic loss, for tumor suppressor gene inactivation.

Aged↗