Biomedical subjects

K S Sridhar

Publications and source records attributed to K S Sridhar.

At least 19 recordsLinked to original sources

PubMed2001

NASA/American Cancer Society High-Resolution Flow Cytometry Project - III. Multiparametric analysis of DNA content and electronic nuclear volume in human solid tumors.

BACKGROUND: The NASA/American Cancer Society (ACS) flow cytometer can simultaneously measure electronic nuclear volume (ENV) and DNA content of nuclei. The preceding articles in this volume ("NASA/American Cancer Society High-Resolution Flow Cytometer Project-I") described the schematics, performance, and procedures used for the preparation of nuclei for analysis on this unit. In the present article, we describe the analysis of selected human tumors using the ratio of ENV/DNA content (nuclear packing efficiency [NPE]). METHODS: Tumor specimens (frozen) were minced with scalpels and stained with 1-10 microg/ml of 4',6-diamidino-2-phenylindole (DAPI) dihydrochloride at pH 6.0-7.2. Trout erythrocytes were used as internal standards. Data on ENV and DNA content were collected in list mode files. Propidium iodide-stained nuclei, analyzed on a Coulter XL cytometer, were used for comparison. RESULTS: Simultaneous measurement of ENV and DNA makes it possible to discriminate between hypodiploid or hyperdiploid tumor cells, as well as to differentiate between near-diploid aneuploid and diploid cells on the basis of their increased ENV. The NPE ratio is a valuable parameter for the detection of small quantities of tumor cells, separating overlapping diploid and aneuploid populations for cell cycle analysis and characterizing the level of differentiation in some tumors. CONCLUSION: NPE analysis provides unique measuring capabilities for the study of human solid tumors by flow cytometry.

American Cancer Society↗

PubMed2000

Synergistic effect of prochlorperazine and dipyridamole on the cellular retention and cytotoxicity of doxorubicin.

Incubation of drug-resistant human tumor cells with a combination of prochlorperazine and dipyridamole has additive/synergistic effect on the cellular retention and cytotoxicity of doxorubicin. In patients administered a fixed dose of doxorubicin and prochlorperazine with escalating doses of dipyridamole, mean plasma levels of dipyridamole and prochlorperazine achieved were as high as 3.01 +/- 0.41 microm and 0.94 +/- 0.09 microm, respectively. Plasma samples from patients were analyzed in an in vitro assay to monitor the effect on the cellular retention of tritium-labeled daunorubicin in MDR1-transfected P388 cells. In 22 of 49 of the plasma samples analyzed, the daunorubicin in efflux blocking activity was one-half or greater than that of cells incubated with 12.5 microM verapamil, a well-known efflux blocker. These observations suggest that a combination of prochlorperazine and dipyridamole may enhance cellular doxorubicin retention by blocking efflux while reducing normal tissue toxicity and unwanted side effects in vivo.

Animals↗

PubMed1999

Effects of cis-platinum chemotherapy on otoacoustic emissions: the development of an objective screening protocol. Third place--Resident Clinical Science Award 1998.

To develop an objective, fast, and simply performed screening protocol for cis -platinum (CP) ototoxicity, we compared the efficacy of screening with distortion-product otoacoustic emissions (DPOAEs) with the outcome of both conventional and ultra-high-frequency (UHF) audiometry. Baseline audiometric and DPOAE testing was performed in 66 patients, 33 of whom met criteria for inclusion in the final database. Comparisons were made between baseline measurements and those recorded before subsequent CP infusions. Outcomes were analyzed clinically and with paired repeated-measures analysis of variance. Results indicated that DPOAEs and UHF were better measures than conventional audiometry. Further, DPOAEs may be better suited for screening older patients receiving CP chemotherapy because DPOAEs are as sensitive as UHF and are present in a greater number of these patients. Screening with DPOAEs may be enhanced by testing only in the 3- to 5.2-kHz range, thus decreasing testing time. Higher time averages to increase the signal-to-noise ratio and use of this narrower bandwidth might also allow for accurate bedside testing.

Adult↗

PubMed1998

Digital clubbing and lung cancer.

OBJECTIVES: To determine the relative frequency of clubbing in small cell lung carcinoma (SCLC) versus non-small cell lung carcinoma (NSCLC). DESIGN: Examine patients with lung cancer for digital clubbing and relate the findings to the histopathologic subtype of lung cancer. SETTING: Cancer center at a tertiary teaching hospital. PATIENTS OR PARTICIPANTS: One hundred and eleven consecutive patients with a pathological diagnosis of lung cancer examined by one physician (KSS). INTERVENTIONS: None. MEASUREMENTS AND RESULTS: Clubbing was present in 32 (29%) of the 111 patients with lung cancer. Clubbing was more common in women (40%) than in men (19%; chi2 test p = 0.011), and was more common in patients with NSCLC (35%) than those with SCLC (4%; chi2 test p = 0.0036). CONCLUSION: In a prospective study, digital clubbing was less frequently observed in men than women and in patients with SCLC than NSCLC. These clinical observations may assist in the initial evaluation of patients for planning workup and therapy.

Carcinoma, Non-Small-Cell Lung↗

PubMed1998

Somatostatin receptor expression in Hürthle cell cancer of the thyroid.

Somatostatin receptor expression, which was not a previously described marker for Hürthle cell cancer of the thyroid, was demonstrated by in vivo imaging with (111)In-pentetreotide in three patients. This phenomenon not only adds another imaging technique to the nuclear medicine armamentarium for detecting recurrent and metastatic cancer in patients with Hürthle cell cancer but also opens up an alternative therapeutic avenue with somatostatin analogs or their radiolabeled compounds.

Adenoma, Oxyphilic↗

PubMed1997

Simultaneous quantitation of plasma doxorubicin and prochlorperazine content by high-performance liquid chromatography.

A high-performance liquid chromatographic method has been developed and tested for simultaneous extraction, elution and determination of doxorubicin and prochlorperazine content in human plasma samples. The procedure consists of extraction through a conditioned C18 solid-phase extraction cartridge, elution from a Spherisorb C8 reversed-phase column by an isocratic mobile phase (60% acetonitrile, 15% methanol and 25% buffer) followed by detection with electrochemical and fluorescence detectors. Recovery of doxorubicin and prochlorperazine from pooled human plasma samples (n=3) containing 100 ng/ml of the two drugs was 77.8+/-3.5% and 89.1+/-6.0%, respectively. The lower limits of quantitation for doxorubicin and prochlorperazine in plasma samples were 6.25 ng/ml and 10 ng/ml, respectively. A linear calibration curve was obtained for up to 2 microg/ml of doxorubicin and prochlorperazine. This combination method may be of particular value in clinical studies where phenothiazines such as prochlorperazine are used to enhance retention of doxorubicin in drug resistant tumor cells.

Antibiotics, Antineoplastic↗

PubMed1997

Hyperfractionated radiation therapy and 5-fluorouracil, cisplatin, and mitomycin-C (+/- granulocyte-colony stimulating factor) in the treatment of patients with locally advanced head and neck carcinoma.

BACKGROUND: The authors had previously reported preliminary results of a treatment regimen of concurrent hyperfractionated radiation therapy and chemotherapy in patients with locally advanced head and neck carcinoma that demonstrated both feasibility and high local control. In an attempt to reduce acute mucosal and hematologic toxicity, granulocyte-colony stimulating factor (G-CSF) was added during the second phase of this study. METHODS: Seventy patients (53 with Stage IV and 17 with Stage III disease) were entered between May 1988 and June 1995 into a Phase I/II trial of concurrent radiation therapy (74.4 gray (Gy) total dose; 1.20 Gy twice daily), 5-fluorouracil (1000 mg/m2/24 hours for 72 hours), and cisplatin (50 mg/m2) for 3 cycles with the addition of mitomycin C (8 mg/m2) in Cycle 2. G-CSF was added after the initial entry of 34 patients. RESULTS: At a median follow-up of 41 months (range, 12-80 months), 44 patients were alive with a projected median overall survival of 54 months. Grade 3/4 mucositis, observed in 65% of patients, was equally prevalent and prolonged in both G-CSF-treated (+) and G-CSF-naive (-) patients. Grade 3/4 leukopenia was present in 45% and 36% of G-CSF- and G-CSF+ patients, respectively. The 3-year locoregional control and cause specific survival rates were 68% and 75%, respectively. CONCLUSIONS: This regimen was feasible and effective but caused severe mucositis. No benefit was derived from the addition of G-CSF. This regimen deserves further modification to reduce acute mucositis toxicity yet maintain the high locoregional control rate.

Adult↗

PubMed1996

Cisplatin and continuous infusion of fluorouracil followed by radiation and weekly carboplatin in the treatment of locally advanced head and neck cancer: a Hellenic Cooperative Oncology Group study.

Induction chemotherapy followed by radiation has been extensively studied in an effort to improve local control and possibly overall survival of patients with locally advanced head and neck cancer. From June 1989 until May 1991, 39 patients with locally advanced squamous cell carcinoma of the head and neck (SCCHN) were treated with 3 cycles of induction chemotherapy, consisting of cisplatin (100 mg/m2 d 1) and fluorouracil (1000 mg/m2 d 2-6) followed by radiation potentiated by weekly administration of carboplatin (60 mg/m2). Surgery was performed in selected patients with residual disease after the combined modality approach. Four cycles of adjuvant chemotherapy with carboplatin (325 mg/m2) and bleomycin (15 u) were administered in those patients who demonstrated a partial response after locoregional treatment. There were 36 men and 3 women with a median age of 56 (range 39-74) years and Karnofsky performance status of 70 (range 60-100). The primary site of the tumor was nasopharynx (8), oropharynx (8), hypopharynx (3), oral cavity (4), larynx (13), paranasal sinus (2), and salivary glands (1). Thirty-two (82%) patients presented with stage IV disease. After the completion of induction chemotherapy, 14 (36%, 95% CI 21-53%) patients achieved a complete response (CR). This CR rate was increased to 56% (95% CI, 42-74%) after locoregional treatment. Main toxicities included nausea/vomiting (56%), leukopenia (40%), anemia (30%), thrombocytopenia (10%), stomatitis (28%), diarrhea (17%), and alopecia (12%). Median relapse-free survival was 18 (1-50) months, median time to progression was 13 (0.3-58.5) months, and median survival 19 (0.3-59) months. Induction chemotherapy with cisplatin and fluorouracil followed by radiation potentiated with carboplatin is feasible. However, this combined modality approach, as applied in the present study, does not appear to yield superior results than those reported with chemotherapy followed by radiation alone.

Animals↗

PubMed1995

Prognostic significance of DNA aneuploidy in diffuse malignant mesothelioma.

DNA ploidy of pepsin digested preparations of 48 paraffin-embedded specimens from 19 patients with histologically confirmed malignant mesothelioma was determined by laser flow cytometry. Eight of the 19 tumors (42%) were diploid and 11 (58%) were aneuploid. Of the aneuploid tumors, only one showed multiploidy. The median survival time of the patients with diploid tumors was 19, 16, and 14 months from the onset of symptoms, diagnosis, and treatment, respectively. The median survival in patients with aneuploid tumors was 8, 7, and 7 months from the onset of first symptoms, diagnosis, and treatment. Thus, patients with diploid tumors lived longer than patients with aneuploid tumors. These results suggest that DNA ploidy analysis may be of prognostic value in malignant mesothelioma.

Adult↗

PubMed1995

Lung cancer in patients with human immunodeficiency virus infection.

This retrospective study determined the clinical course of lung cancer in patients with human immunodeficiency virus (HIV) infection. A total of 23 patients with HIV infection archived as lung cancer were studied: 16 were identified from about 1,000 lung cancer patients entered in the tumor registry and medical records of Jackson Memorial Hospital, 7 were identified from about 1,000 HIV-positive patients entered in the Special Immunology registry of Veterans Administration Medical Center, 4 patients did not have pathologic confirmation of lung cancer, and 19 patients, all men, met the criteria for analysis (histopathologic diagnosis of lung cancer and HIV+ by serology). The median age was 47 (range: 36-66). Risk factors for HIV were homosexuality (6 patients), blood transfusion (3), promiscuity (5), intravenous drug abuse (4), and none (3). Six patients had a history of coexistent pulmonary tuberculosis and 5 had Pneumocystis carinii pneumonia. Median survival from diagnosis of lung cancer was 3 months. Advanced stages of both HIV infection and lung cancer may account for the poor survival. All patients were men and noted to be younger than other patients with lung cancer.

Adult↗

PubMed1995

Bronchogenic carcinoma in HIV-positive patients: findings on chest radiographs and CT scans.

OBJECTIVE: The radiographic manifestations of bronchogenic carcinoma in HIV-positive individuals may resemble or accompany changes of inflammatory disease. To provide information that is useful in the differential diagnosis, we studied the findings on plain radiographs and chest CT scans in 30 HIV-positive patients with proven bronchogenic carcinoma and correlated the radiographic features with the presence or absence of thoracic opportunistic infection. SUBJECTS AND METHODS: Thirty HIV-positive individuals had bronchogenic carcinoma diagnosed at our institution between 1986 and 1993. Fourteen (47%) of the 30 had AIDS at the time of cancer diagnosis. All but one of the patients were men, and the median age at diagnosis was 48 years (range, 32-66 years). Most (90%) had a history of smoking. Eighteen (60%) of the 30 had a history of pulmonary tuberculosis, Pneumocystis carinii pneumonia, or both. We retrospectively reviewed all available chest radiographs (n = 27) and chest CT scans (n = 25) for tumor size and location, adenopathy, pleural disease, and pulmonary infiltrates. RESULTS: Eighteen tumors (60%) were peripheral, 11 (37%) were central (hilar or mediastinal), and one manifested as a metastatic pleural mass. Of the peripheral tumors, 17 (94%) were in the upper lobes. All the central tumors showed obstructive consolidation of lung in the distribution of the affected airway. Adenopathy was present in 63% of the patients, and pleural effusions or masses were seen in 33%. A history of tuberculosis or Pneumocystis carinii pneumonia was present in 83% of the patients with peripheral tumors but only 27% of the patients with central lesions (p = .005). Superimposed infiltrates were present in six patients (20%). Three (17%) of 18 peripheral tumors were obscured by or mistaken for inflammatory disease, delaying the diagnosis of cancer. CONCLUSION: Bronchogenic carcinoma usually manifests as a peripheral upper lobe mass in HIV-positive patients with a history of tuberculosis or Pneumocystis carinii pneumonia, whereas central masses are more common in patients without a history of thoracic opportunistic infection. Carcinoma should be suspected in patients with peripheral lesions that persist despite appropriate antibiotic therapy.

AIDS-Related Opportunistic Infections↗

PubMed1995

Integrating the ECG power-line interference removal methods with rule-based system.

The power-line frequency interference in electrocardiographic signals is eliminated to enhance the signal characteristics for diagnosis. The power-line frequency normally varies +/- 1.5 Hz from its standard value of 50 Hz. In the present work, the performances of the linear FIR filter, Wave digital filter (WDF) and adaptive filter for the power-line frequency variations from 48.5 to 51.5 Hz in steps of 0.5 Hz are studied. The advantage of the LMS adaptive filter in the removal of power-line frequency interference even if the frequency of interference varies by +/- 1.5 Hz from its normal value of 50 Hz over other fixed frequency filters is very well justified. A novel method of integrating rule-based system approach with linear FIR filter and also with Wave digital filter are proposed. The performances of Rule-based FIR filter and Rule-based Wave digital filter are compared with the LMS adaptive filter.

Algorithms↗

PubMed1994

Doxorubicin retention and chemoresistance in human mesothelioma cell lines.

Eight cell lines were established from the pleural effusion of 4 patients with malignant mesothelioma. The most sensitive (FCCMES-4) and the most resistant (FCCMES-2) mesothelioma cell lines had IC50 of 0.66 and 1.85 microM for doxorubicin in clonogenic assays, respectively. In comparison with murine leukemic P388 cells, mesothelioma cell lines were 7.5- to 21-fold more resistant to doxorubicin. Co-incubation with verapamil significantly increased doxorubicin retention in one of the cell lines (FCCMES-2) expressing P-glycoprotein in 16.8% of the cells. These results indicate that doxorubicin resistance may be intrinsic in refractory mesothelioma patients and P-glycoprotein-mediated drug efflux may be involved in resistance of some of the mesotheliomas.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMed1994

Phase I and pharmacokinetics studies of prochlorperazine 2-h i.v. infusion as a doxorubicin-efflux blocker.

In an earlier phase I study, we reported that the maximal tolerated dose (MTD) of prochlorperazine (PCZ) given as a 15-min i.v. infusion was 75 mg/m2. The highest peak plasma PCZ concentration achieved was 1100 ng/ml. The present study was conducted to determine if PCZ levels high enough to block doxorubicin (DOX) efflux in vitro could be achieved and sustained in vivo by increasing the duration of i.v. infusion from 15 min to 2 h. The treatment schedule consisted of i.v. prehydration with at least 500 ml normal saline (NS) and administration of a fixed standard dose of 60 mg/m2 DOX as an i.v. bolus over 15 min followed by i.v. doses of 75, 105, 135, or 180 mg/m2 PCZ in 250 ml NS over 2 h. The hematologic toxicities attributable to DOX were as expected and independent of the PCZ dose. Toxicities attributable to PCZ were sedation, dryness of mouth, anxiety, akathisia, hypotension, cramps, and confusion. The MTD of PCZ was 180 mg/m2. Large interpatient variation in peak PCZ plasma levels (91-3215 ng/ml) was seen, with the plasma half-life (t1/2 alpha) being approximately 57 min in patients given 135-180 mg/m2 PCZ. The volume of distribution (Vd), total clearance (ClT), and area under the curve (AUC) were 350.1 +/- 183.8 1/m2, 260.7 +/- 142.7 l m2 h-1 and 1539 +/- 922 ng ml h-1, respectively, in patients given 180 mg/m2 PCZ and the respective values for patients receiving 135 mg/m2 were 48.9 +/- 23.76 l/m2, 33.2 +/- 2.62 l m2 h-1, and 4117 +/- 302 ng ml h-1. High PCZ plasma levels (> 600 ng/ml) were sustained in all patients treated with 135 mg/m2 PCZ for up to 24 h. DOX plasma elimination was biphasic at 135 and 180 mg/m2 PCZ, and a > 10-ng/ml DOX plasma level was maintained for 24 h. Partial responses were seen in three of six patients with malignant mesothelioma, in two of ten patients with non-small-cell lung carcinoma, and in the single patient with hepatoma. Our data show that PCZ can be safely given as a 2-h infusion at 135 mg/m2 with clinically manageable toxicities. The antitumor activity of the combination of DOX and PCZ needs to be confirmed in phase II trials.

Adult↗

PubMed1994

The role of steroids in the management of metastatic carcinoma to the brain. A pilot prospective trial.

This prospective study attempted to evaluate the indications for glucocorticoids which are commonly given to patients with brain metastases. Twelve patients with histologically confirmed malignancies and radiographically documented brain metastases were enrolled. Patients were scored for general performance status and neurologic function class. All subjects were given high-dose dexamethasone (HDD) for 48 hours and then randomized to receive either intermediate-dose dexamethasone (IDD) or no steroids with cranial radiotherapy. Of these 12 study patients, 3 achieved a complete response, 1 partial response, and 8 nonresponses to HDD. Seven patients had IDD, while five received no IDD. Although a small sample size prevented any statistical analysis, this study does suggest that the place for using glucocorticoids in treating patients with metastatic carcinoma to the brain remains uncertain and should be evaluated in a cooperative prospective trial.

Adult↗

PubMed1994

A randomized clinical trial in bronchogenic small-cell carcinoma evaluating alternating maintenance therapy of vincristine, adriamycin, procarbazine, and etoposide (VAPE) with cyclophosphamide, CCNU, and methotrexate (CCM) versus CCM maintenance alone in complete responders following VAPE induction and late intensification.

Initially, 109 evaluable patients with locally advanced or metastatic small cell lung cancer (SCLC) were treated with vincristine, Adriamycin, procarbazine, and etoposide (VAPE). Partial (PR) or nonresponders (NR) were crossed to CCM (cyclophosphamide, CCNU, and methotrexate) and then to HMiVe (hexamethylmelamine, mitomycin C, vinblastine) sequentially at maximum response. Complete responders (CR) were intensified by 50% with VAPE primarily and randomized to VAPE, alternating with CCM or CCM alone during maintenance. CR patients with limited disease received local thoracic irradiation and prophylactic cranial irradiation (PCI), whereas those with extensive disease received PCI alone. There were 45 patients (41%) who achieved a CR to chemotherapy, and 27 patients were eligible for randomization. Of 12 CR patients randomized to alternating therapy (VAPE/CCM), the median survival was 25.9 months compared to 12.9 months for 15 CR patients randomized to continuous CCM (P = .049). In addition, 35 patients achieved a PR (32%) and 29 were NR (27%). Overall median survivals were significantly different for the CR patients (13.0 months) as compared to PR (7.6 months) and NR patients (6.4 months). Late intensification did not appear to add substantially to survival while contributing to toxicity. In summary, VAPE is a new outpatient regimen for SCLC, which is highly effective as an induction regimen with moderate hematologic toxicity and predominantly gastrointestinal nonhematologic toxicity.

Aged↗

PubMed1994

Radiation therapy and concurrent cisplatin administration in locally advanced head and neck cancer. A Hellenic Co-operative Oncology Group study.

In an attempt to improve local control of locally advanced head and neck cancer, radiation therapy was combined with cisplatin. Forty-eight patients entered into this study. All patients were irradiated with a 60Co unit and according to the protocol they should receive 70 Gy in the tumor area and 45 Gy in the rest of neck. Cisplatin was administered at a dose of 100 mg/m2 on days 2, 22 and 42. Thirty-seven (80%) patients received the total radiation dose as initially planned. Thirty-four (72%) patients achieved complete and 5 (10%) partial response. Grade 3-4 toxicities included vomiting (14%), stomatitis (4%), diarrhea (2%), myelotoxicity (14%), hoarseness (4%), dysphagia (30%), weight loss (32%), nephrotoxicity (4%) and dermatitis (2%). After a median follow-up of 26 (range, 18-33) months, 16 patients have died. Among the 35 complete responders 6 later on relapsed. Median relapse-free survival has not yet been reached. Combined radiation therapy and cisplatin appears to be a highly active treatment in patients with advanced head and neck cancer as far as primary locoregional response is concerned.

Adolescent↗

PubMed1993

Prochlorperazine as a doxorubicin-efflux blocker: phase I clinical and pharmacokinetics studies.

Doxorubicin (DOX) efflux in drug-resistant cells is blocked by phenothiazines such as trifluoperazine (TFP) and prochlorperazine (PCZ) in vitro. The present phase I study was conducted in 13 patients with advanced, incurable, nonhematologic tumors to determine whether PCZ plasma levels high enough to block DOX efflux could be achieved in vivo. The treatment schedule consisted of prehydration and i.v. administration of 15, 30, 50, and 75 mg/m2 PCZ followed by a standard dose of 60 mg/m2 DOX. The hematologic toxicities attributable to DOX were as expected and independent of the PCZ dose used. Toxicities attributable to PCZ were sedation, dryness of the mouth, cramps, chills, and restlessness. The maximal tolerated dose (MTD) of PCZ in this schedule was 75 mg/m2. Pharmacokinetic analysis indicated a large interpatient variation in peak plasma PCZ levels that ranged from 95 to 1100 ng/ml. The three plasma half-lives of PCZ were: t1/2 alpha (+/- SE), 20.9 +/- 5.3 min; t1/2 beta, 1.8 +/- 0.3 h; and t1/2 gamma, 21.9 +/- 5.3 h. The volume of distribution (Vd), total clearance (ClT), and area under the curve (AUC) for PCZ were 2254 +/- 886 l/m2, 60.2 +/- 13.5 l m-2 h-1, and 1624 +/- 686 ng ml-1 h, respectively. DOX retention in tumor cells retrieved from patients during the course of therapy indicated the appearance of cells with enhanced DOX retention. The combination of DOX and high-dose i.v. PCZ appeared to be safe, well tolerated, and active in non-small-cell lung carcinoma.

Aged↗