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Biomedical subjects

A C Mehta

Publications and source records attributed to A C Mehta.

At least 19 recordsLinked to original sources
PubMed2005

From cystic pulmonary airway malformation, to bronchioloalveolar carcinoma and adenocarcinoma of the lung.

Bronchioloalveolar carcinoma (BAC) of the lungs is a known morphological subtype of nonsmall cell cancer. The current study presents several carcinogenetic theories of BAC and the possible relationship with atypical adenomatous hyperplasia and congenital pulmonary airway malformation (CPAM). The authors present an unusual case of BAC developed in an area of CPAM, with subsequent progression to metastatic adenocarcinoma (AC). The case is unique due to the combination of: early age of presentation; neoplastic transformation of a CPAM; unaltered course over 15 yrs; and its particular pattern of slow morphogenesis and degeneration into an invasive AC of the lung. The case also presents the unique features of a long-standing, unaltered natural course of paediatric BAC towards invasive and metastatic AC, illustrating that lack of growth over many years cannot be entirely trusted as a criterion of benignity. In conclusion, clinicians and pathologists need to be aware of the fact that congenital pulmonary airway malformation so far represents the only known pre-invasive lesion for mucinous bronchioloalveolar carcinoma.

Adenocarcinoma↗
PubMed2004

High-dose therapy and autologous stem cell transplant does not result in long-term disease-free survival in patients with recurrent chemotherapy-sensitive ALK-negative anaplastic large-cell lymphoma.

Primary systemic anaplastic lymphoma kinase (ALK)-negative anaplastic large-cell lymphoma (ALCL) has a poor prognosis. This study sought to determine if high-dose therapy and ASCT results in long-term disease-free survival (DFS) in patients with recurrent, chemotherapy-sensitive ALK-negative ALCL. All patients with non-Hodgkin's lymphoma (NHL) who underwent ASCT at Wake Forest University and Upstate Medical University from 1 January 1990 to 12 December 2002 were reviewed to determine if they had T-, B- or null-cell NHL that was CD30+/CD15-/ALK negative. In all, 16 patients were thus identified as having ALK-negative ALCL. All 16 patients underwent ASCT at the time of first relapse and form the basis of this report. Median age of the 16 patients was 51 years. There were 11 males and five females. International prognostic index scores in 12 patients at the time of relapse were: low 3, LI 6 and HI 3. Of 15 patients, 13 relapsed after ASCT; one patient was lost to follow-up. Median progression-free survival for the 15 patients was 12 weeks (3-212+ weeks). Of 15 patients, 10 have died; nine of recurrent disease. Median overall survival for the 15 evaluable patients was 72 weeks. In our experience, high-dose therapy and ASCT does not produce long-term DFS in patients with recurrent chemotherapy-sensitive ALK-negative ALCL.

Anaplastic Lymphoma Kinase↗
PubMed2001

Assessment of a bronchoscopy simulator.

The study objective was to validate a flexible bronchoscopy simulator by determining if it could differentiate between expert and novice bronchoscopists. A subsequent evaluation phase was then done to determine whether use of the simulator would improve the rate of bronchoscopy skill acquisition for new pulmonary fellows. A multicenter prospective cohort study was performed using a bronchoscopy simulator. Three cohorts were evaluated based on the number of bronchoscopies previously performed: "experts" (> 500, n = 9), "intermediates" (25 to 500, n = 8), and "novices" (none, n = 11). Each participant performed two simulated cases with performance measures being recorded by the simulator. Performance measures that distinguished between groups were then used to evaluate the learning curve for new fellows training on the simulator. A randomized-controlled trial was then conducted comparing the quality of bronchoscopy performance for new pulmonary fellows who were trained either with conventional methods or with the simulator. Expert bronchoscopists performed better on the simulator than intermediates who performed better than novices in terms of procedure time, percentage of segments visualized, time in red-out, and wall collisions. Training of new fellows demonstrated that after performing 20 bronchoscopic simulations, the skill level acquired with the simulator significantly improved in terms of speed, percentage of segments visualized, time in red-out, and collisions. Fellows trained on the simulator performed better than fellows trained using conventional methods during their first actual bronchoscopies as assessed by procedure time (815 versus 1,168 s, p = 0.001), a bronchoscopy nurse's subjective quality assessment score (7.7 +/- 0.3 versus 3.7 +/- 2.5, p = 0.05), and by a quantitative bronchoscopy quality score (percentage of segments correctly identified/procedure time, 0.119 +/- 0.015 versus 0.046 +/- 034, p = 0.03). In conclusion, the bronchoscopy simulator was able to accurately assess bronchoscopy experience level. Training new fellows on the bronchoscopy simulator leads to more rapid acquisition of bronchoscopy expertise compared with conventional training methods. This technology has the potential to facilitate bronchoscopy training and to improve objective evaluations of bronchoscopy skills.

Adult↗
PubMed2001

Hypogammaglobulinemia in lung transplant recipients.

BACKGROUND: Infectious complications continue to represent a significant source of morbidity and mortality in lung transplant recipients. Identifying specific, remediable immune defects is of potential value. After one lung transplant patient with recurrent infections was noted to be severely hypogammaglobulinemic, a screening program for humoral immune defects was instituted. The objectives were to define the prevalence of hypogammaglobulinemia in lung transplant recipients, assess levels of antibody to specific pathogens, and correlate infectious disease outcomes and survival with immunoglobulin levels. METHODS: All lung transplant recipients followed at a single center between October 1996 and June 1999 underwent a posttransplant humoral immune status survey as part of routine posttransplant follow-up. This survey consists of total immunoglobulin levels (IgG, IgM, IgA), IgG subclasses (IgG1-4), and antibody titers to Pneumococcus, diphtheria, and tetanus. Since February 1997, this survey has been incorporated into the pretransplant evaluation as well. Humoral survey results for October 1996 through July 1999 were recorded, and clinical information on major infectious disease outcomes was obtained from chart reviews, discharge summaries, the Cleveland Clinic Unified Transplant Database, and review of all microbiological studies and pathology results for each patient. RESULTS: Of 67 patients with humoral immune surveys drawn posttransplant, 47 (70%) had IgG levels less than 600 mg/dl (normal 717-1410 mg/dl), of which 25 (37%) had IgG levels less than 400 mg/dl ("lowest IgG group") and 22 (33%) had IgG levels between 400 and 600 mg/dl ("moderately low IgG group"). A total of 20 patients (30%) had IgG levels of more than 600 mg/dl ("normal IgG group"). Infections that were significantly more common in the lowest IgG group, and more common in the moderately low IgG group than the normal IgG group, included: number of pneumonias (P=0.0006), bacteremias (P=0.02), total bacterial infections (P=0.002), tissue-invasive cytomegalovirus (P=0.01), invasive aspergillosis (P=0.001), total fungal infections (P=0.001), and total infections (P=0.006). Median hospital days per posttransplant year was significantly different in the three groups (11.0 vs. 7.4 vs. 2.8 days, P=0.0003.) Invasive aspergillosis occurred in 44% of the lowest IgG group, 9% of the moderately low IgG group, and 0% of the normal IgG group (P<0.001). Survival was poorest in the lowest IgG group and intermediate in the moderately low IgG group. IgG subclass deficiencies occurred in a variety of patterns. Hypogammaglobulinemic patients lacked protective responses to Pneumococcus in 14/47 (30%), diphtheria in 15%, and tetanus in 19%. In a group of 48 patients screened pretransplant, 90% had normal immunoglobulin levels. CONCLUSIONS: Hypogammaglobulinemia in lung transplant recipients is more common than has been previously recognized. An IgG level of less than 400 mg/dl identifies a group at extremely high risk of bacterial and fungal infections, tissue-invasive cytomegalovirus, and poorer survival. Immunoglobulin monitoring may offer an opportunity for intensive surveillance, tapering of immunosuppression, and preemptive therapy for infection.

Adolescent↗
PubMed2001

Adult airway foreign body removal. What's new?

Signs and symptoms of adult FB aspiration are most often nonspecific. Misdiagnosis and delay in diagnosis frequently occur. Radiographic evaluation is helpful, but flexible bronchoscopy is the gold standard in the identification and localization of an airway foreign body. With increasing experience and development of better accessories, removal using a flexible bronchoscope under local anesthesia can be performed safely and successfully. Review of large series of FB removal indicates a success rate of 86% in more than 400 procedures with flexible bronchoscopy.

Adult↗
PubMed2001

Training bronchoscopists for the new era.

Gustav Killian introduced bronchoscopy a little more than a century ago. At that time, the only way others could learn to perform bronchoscopy was by one-on-one tutoring, using a rigid bronchoscope with no side portals and no imaging devices such as a television camera and monitor. One-on-one teaching remains an integral part of learning how to perform bronchoscopy well, but many new technologies have emerged that make it far less labor intensive to train bronchoscopists. This article focuses on the training of bronchoscopists for the new era.

Bronchoscopy↗
PubMed2001

Enhanced cyclosporine-itraconazole interaction with cola in lung transplant recipients.

BACKGROUND: Invasive aspergillosis is a major cause of morbidity and mortality in lung transplant recipients (LTR), occurring in up to 15% of patients post-transplant. The 14% aspergillus incidence at the Cleveland Clinic Foundation prompted institution of universal prophylaxis with oral itraconazole (ICZ) in 1997. We report our experience with two protocols of ICZ administration in non-cystic fibrosis LTR and the interaction with cyclosporine (CSA). METHODS: Group 1 patients (n=12) were administered ICZ capsules in a fasting or fed state, with or without a histamine-2 (H-2) receptor antagonist or proton pump inhibitor. Group 2 patients (n=12) received the same protocol as group I, but in a fed state with a carbonated beverage (cola) to increase acidity in the stomach to enhance absorption of ICZ. The ICZ dose was 200 mg/d, given as one daily dose. A historical control group (n=10) did not receive chemoprophylaxis with ICZ. CSA daily doses, dose intervals, concentration, cost, and random ICZ levels were documented over a 4-month period of time and compared using generalized estimating equations. RESULTS: The daily CSA mg/kg/d dose decreased over time in all three groups, but no differences were found between the three groups. The CSA dosing interval over time was significantly prolonged in group 2 compared to group 1 or the control group (p< or =0.003). Over time, there was no difference in CSA concentration between all groups. There was no difference in cost over time between the three groups; however, the mean cost of CSA therapy was significantly lower in group 2 compared to the control group (p=0.025). Group 2 administered ICZ with cola had greater random blood concentrations of ICZ (p=0.019). CONCLUSIONS: ICZ capsules administered in a fed state with a cola resulted in greater random levels of ICZ, a decrease in cost/d of CSA, and a prolongation of CSA dosing interval. Although daily CSA dosage trended lower in group 2, it did not reach statistical significance. We believe these changes in CSA dosing over time reflect increased absorption of ICZ and recommend verifying ICZ absorption with an itraconazole level, especially when CSA intervals are not prolonged.

Antifungal Agents↗
PubMed2001

Increased atherosclerosis in myeloperoxidase-deficient mice.

Myeloperoxidase (MPO), a heme enzyme secreted by activated phagocytes, generates an array of oxidants proposed to play critical roles in host defense and local tissue damage. Both MPO and its reaction products are present in human atherosclerotic plaque, and it has been proposed that MPO oxidatively modifies targets in the artery wall. We have now generated MPO-deficient mice, and show here that neutrophils from homozygous mutants lack peroxidase and chlorination activity in vitro and fail to generate chlorotyrosine or to kill Candida albicans in vivo. To examine the potential role of MPO in atherosclerosis, we subjected LDL receptor-deficient mice to lethal irradiation, repopulated their marrow with MPO-deficient or wild-type cells, and provided them a high-fat, high-cholesterol diet for 14 weeks. White cell counts and plasma lipoprotein profiles were similar between the two groups at sacrifice. Cross-sectional analysis of the aorta indicated that lesions in MPO-deficient mice were about 50% larger than controls. Similar results were obtained in a genetic cross with LDL receptor-deficient mice. In contrast to advanced human atherosclerotic lesions, the chlorotyrosine content of aortic lesions from wild-type as well as MPO-deficient mice was essentially undetectable. These data suggest an unexpected, protective role for MPO-generated reactive intermediates in murine atherosclerosis. They also identify an important distinction between murine and human atherosclerosis with regard to the potential involvement of MPO in protein oxidation.

Animals↗
PubMed2001

The humoral immune response to influenza vaccination in lung transplant patients.

The purpose of this study was to evaluate the humoral immune response to influenza vaccination in lung transplant recipients. Antibody levels to the three viral antigens included in the 1999-2000 trivalent influenza vaccine (A/Sydney/5/97-like (H3N2), A/Beijing262/95-like (H1N1), and B/Yamanashi/16/ 98) were measured before and 4 weeks postvaccination in 43 lung transplant recipients and 21 healthy adult controls. The ability to develop protective antibody levels, a serological response, and the magnitude of change in levels were assessed. The humoral immune response to influenza vaccination was significantly lower in the transplant group for all three viral antigens. To A/Sydney, 95% of the control group and 40% of the transplant group developed protective levels (p=0.0009); to A/Beijing, 71% of the control group and 30% of the transplant group developed protective levels (p=0.004); and to B/Yamanashi, 48% of the control group and 19% of the transplant group developed protective levels (p=0.02). Those receiving cyclosporine had lower antibody responses when compared to those receiving tacrolimus (r=-0.3056, p=0.0463). The humoral immune response to influenza vaccination in lung transplant recipients is poor. Lung transplant recipients receiving cyclosporine may have a lower antibody response than those receiving tacrolimus. Alternative prevention strategies may be needed.

Adult↗
PubMed2001

Therapeutic flexible bronchoscopy.

Since the development of the flexible bronchoscope in late 1960s, its use in the management of various pulmonary disorders, especially lung Ca, has expanded tremendously. It is not only of great diagnostic value, with the recent development of various therapeutic modalities such as Nd:YAG laser, tracheobronchial stents, and cryotherapy, but also its value in management of terminal lung Ca has improved dramatically. Its potential in curing early-stage lung Ca presently is being explored. At present, it is at least partially successful in achieving this goal. More importantly, because of lack of the training in RB and widespread usage of FB, it is more likely that its role in the various interventional procedures, such as Nd:YAG laser therapy, tracheobronchial stent deployment, brachytherapy, and cryotherapy, will grow exponentially. Because of availability of a variety of therapeutic modalities, such as APC, PDT, and balloons, interventional pulmonologists are well equipped to improve the quality of life of terminally ill patients with cancer and maybe to cure early stage lung Ca.

Brachytherapy↗
PubMed2001

Transbronchial needle aspiration of central and peripheral nodules.

Wang and Terry first described the technique of sampling of mediastinal lymph nodes using a flexible bronchoscope (FB) in 1983. Since then, the scope of transbronchial needle aspiration (TBNA) has increased enormously, and its value for diagnosis of central and peripheral lung lesions, even in the absence of endobronchial disease, is now recognized. Improvements in the diagnostic yield of TBNA aspirates, and increasing knowledge of predictors of a positive aspirate, has reduced the need for mediastinoscopy, and occasionally thoracotomy, with benefits in terms of reduced healthcare costs and improved patient welfare. Despite the fact that TBNA is a minimally invasive procedure, also for the staging of lung cancer, it unfortunately remains underutilized. This review aims to give the reader an overview of the indications, outcome data, technical considerations, and advantages of routinely performing TBNA. The technical suggestions to improve the yield from TBNA will hopefully provide greater understanding of this modality and help the pulmonologist to incorporate it in daily practice with more confidence.

Biopsy, Needle↗
PubMed2000

Increased alveolar macrophage nuclear factor-kappa B activation and macrophage inhibitory protein-1alpha levels in lung transplant patients.

BACKGROUND: Lung transplantation is increasingly used as the treatment for many end-stage pulmonary diseases. A major cause of morbidity and mortality in patients who undergo lung transplantation is rejection of the allograft. Proinflammatory macrophage-derived cytokines may sustain and/or enhance the immunological response to lung allograft antigens. Nuclear factor-kappa B (NF-kappaB) is a transcription factor that regulates the production of many of these cytokines and growth factors in alveolar macrophages (AMs). The aim of our study was to evaluate the activation of NF-kappaB in AMs and the levels of one of the proinflammatory cytokines whose production it controls, macrophage inhibitory protein-1alpha (MIP-1alpha), in AMs from transplanted lungs compared to those from healthy controls. METHODS: Twenty-eight (28) transplant recipients were included in the study. NFkappaB activation was evaluated by electrophoretic mobility shift assay of whole cell extracts and by immunohistochemical analysis on cytospin preparations. Concentrated bronchoalveolar lavage fluid was analyzed by enzyme-linked immunosorbent assay for MIP-1alpha levels. RESULTS: NF-kappaB was activated in alveolar macrophages from transplant patients as compared to healthy controls. MIP-1alpha levels in epithelial-lining fluid were elevated in transplant patients as compared to healthy controls. Increased MIP-1alpha levels correlated with viral infections in the transplant patients. Neither finding was found to correlate with acute rejection by transbronchial biopsy. CONCLUSIONS: These results demonstrate that NF-kappaB activation and MIP-1alpha levels are increased in transplanted lungs and may play a role in the inflammatory cytokine cascade that leads to the long-term tissue damage and allograft rejection in these patients.

Bronchoalveolar Lavage Fluid↗
PubMed2000

Stenting of the tracheobronchial tree.

Endoscopic treatment of endobronchial obstructions is becoming increasingly important. Tracheobronchial stents often are needed in the treatment of obstructions from submucosal or extrabronchial lesions. Tube stents have been available since the early 1960s but are underused because their insertion requires the use of a rigid bronchoscope. With the recent development of metallic stents, interventional radiologists increasingly are involved in the treatment of tracheobronchial obstructions. Metallic stents, easily placed with flexible bronchoscopy, are growing in popularity. All available tracheobronchial stents have been shown in various clinical series to be able to achieve immediate resolution of respiratory symptoms from various tracheobronchial obstructions. A stent's performance, however, should not be based solely on short-term response. Presently, there is no ideal stent because none is free of complications and none are able to consistently maintain life-long patency. Gianturco stents are associated with serious major complications (bronchial perforations and strut fractures) and are no longer recommended for use in the tracheobronchial tree. The Palmaz stent has also fallen into disfavor, because a strong external force, such as a vigorous cough, can recompress it. The Strecker stent can only be used in smaller airways, but may be useful in the accurate stenting of short segment stenoses because it does not foreshorten on deployment. The Wallstent and Ultraflex are our present metallic stents of choice. Both are easy to deploy, available in covered forms, exert adequate radial force, remain relatively stable in position, and have good longitudinal flexibility for use in tortuous airways. Disadvantages include excessive granulation tissue formation and difficulty of removal once the stent has been epithelialized. Metallic stents should be chosen very carefully for use in benign lesions with ongoing active local inflammation or when temporary stenting is needed. In the absence of an ideal stent, technologic advancements will continue. Potential developments include removable metallic stents, biodegradable stents, and chemically and radioactively coated stents. Unquestionably, the expanding stent market will drive scientific research toward the development of the ideal stent. Clearly, physicians need to be ready to assess these technologic advancements.

Bronchi↗
PubMed2000

Role of bronchoscopy in lung cancer.

Advancements in technology and experience have pushed forth the bronchoscope's increasing role in the struggle against lung cancer. The bronchoscope is useful in the following situations: diagnosis, staging, treatment of endobronchial lesions for palliation or cure, early detection of lung cancer, and research. In this article, we provide a concise overview of several endoscopic modalities (i.e., transbronchial needle aspiration, laser photoresection, photodynamic therapy, electrocautery, cryotherapy, brachytherapy, stents, autofluorescence bronchoscopy, and gene therapy). Basic principles, technique, indications, outcome data, and associated complications of each modality are discussed.

Journal Article↗
PubMed2000

Role of Tc-99m MIBI in the evaluation of single pulmonary nodules: a preliminary report.

BACKGROUND: Survival in bronchial carcinoma is closely related to the stage of the disease at the time of diagnosis and a single pulmonary nodule represents a potentially curable stage. This study was conducted to assess the feasibility of using Tc-99m labelled 2-methoxy isobutyl isonitrile (MIBI) to differentiate benign from malignant single pulmonary nodules. METHODS: A prospective study was conducted in the outpatient pulmonary clinic at the Cleveland Clinic Foundation. Twenty five patients with single pulmonary nodules considered indeterminate by their physicians and undergoing a procedure for tissue diagnosis were evaluated by Tc-99m MIBI SPECT scanning prior to definitive testing. Assessment of MIBI uptake was done qualitatively (subjectively) and quantitatively and correlated with the histopathology and nodule size. RESULTS: Of the 21 patients with malignant lesions, 18 had increased uptake of MIBI corresponding to the location of the nodule and were considered positive. The predominant tumour types were large cell (n = 5) and adenocarcinoma (n = 10). All four patients with benign lesions had negative MIBI scans. For malignancy the overall specificity was 100%, sensitivity was 85.7%, positive predictive value was 100%, and negative predictive value was 57%. Quantitative uptake of MIBI correlated with the diameter of the nodule with a correlation coefficient of 0.61 by Spearman's rank sum test. This relationship was statistically significant (p = 0.02). CONCLUSION: This preliminary study suggests that Tc-99m MIBI has a very high specificity and positive predictive value for malignant single pulmonary nodules and might be a useful non-invasive diagnostic modality in their management.

Aged↗
PubMed2000

The utility of transbronchial needle aspiration in the staging of bronchogenic carcinoma.

We conducted a prospective multi-institutional clinical study involving community hospitals and academic medical centers to more carefully define the value of computerized tomography (CT) of the chest with transbronchial needle aspiration (TBNA) in the staging of bronchogenic carcinoma (CA), and to assess the predictors of a positive aspirate. Of 360 individuals determined to have bronchogenic carcinoma, 50 of 81 (62%) with small cell carcinoma (SCC) and 135 of 279 (48%) with non-small cell carcinoma (NSCC) had positive aspirates (p = 0.034). TBNA precluded additional thoracic surgery in a total of 104 of 360 (29%) patients and was exclusively diagnostic of carcinoma in 65 of 360 (18%) cases. Right-sided tumors were more likely to have a positive mediastinal TBNA (p = 0.002 to 0. 01) as were histologic (67 of 118 [57%]) rather than cytology aspirates (228 of 532 [41%]) (p < 0.001). Sensitivity was > 57% in lymph nodes (LN) >/= 10 mm, and among LN of equivalent size, right paratracheal and subcarinal sites were most likely to establish malignancy. Preoperative CT is a valuable adjunct in the staging of CA by TBNA. Increasing LN size, right-sided tumors, right paratracheal and subcarinal locations, use of a histology needle, and the presence of SCC are the best predictors of a positive aspirate.

Adult↗