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Biomedical subjects

H Garewal

Publications and source records attributed to H Garewal.

At least 37 records · Page 2Linked to original sources
PubMed1994

A normal initial colonoscopy after age 50 does not predict a polyp-free status for life.

OBJECTIVES: The prevalence of colon polyps increases with age in the general population. It is unknown whether a lack of adenomatous polyps determined at one time point after the age of 50 is predictive of a subsequent low risk of polyp development. METHODS: Twenty-nine patients between ages 50 and 70 who had no prior history of polyps and had a normal colonoscopy at least 5 yr previously were recruited for follow-up colonoscopy to evaluate the incidence of neoplastic disease in this presumably low-risk group. RESULTS: The incidence of adenomatous polyps after a mean of 5.74 yr was 41.4% (95% confidence interval: 23.5-61.1%). A total of 20 adenomatous polyps were found in 12 patients. Seven polyps were 5 mm or more in size. CONCLUSIONS: We conclude that in patients with no history of colonic neoplasia who are 50 yr old, or older, the finding of a normal colonoscopy does not predict diminished risk of neoplasia.

Adenomatous Polyps↗
PubMed1994

Two-year incidence of colon adenomas developing after tandem colonoscopy.

OBJECTIVES: We attempted to determine an accurate frequency of new polyp growth in a cohort of veteran male patients who were initially cleared of polyps by tandem colonoscopy. METHODS: Followup colonoscopy was performed 2 yr after tandem colonoscopy. A polyp was categorized as "new" if it was not located in a segment of the colon or rectum that had harbored a neoplastic polyp of the same histology at tandem colonoscopy, in contradistinction to lesions designated as "same-segment" polyps. RESULTS: Fifty-eight of 90 patients who had tandem colonoscopy as a part of a previous study were available for follow-up colonoscopy for 2 yr. Ninety-one percent had a history of benign neoplastic polyps or cancer. Neoplastic polyps were documented in 52% (95% CI, 45-74%) of patients at followup, and 38% (95% CI, 26-52%) were found to have a total of 31 "new" lesions. All new lesions were tubular adenomas. The largest number of new polyps in an individual patient was four, and the largest new lesion was 20 mm in size with a flat, linear configuration. Most (25/31) new polyps were < or = 5 mm, and the number of neoplastic polyps per patient at follow-up was less than at tandem colonoscopy. CONCLUSIONS: Approximately one-half of older, male patients with a history of neoplastic polyps will demonstrate neoplastic polyps at 2 yr. In at least one-third of patients, these appear to be new lesions. In some patients, de novo neoplastic polyps can grow to > or = 1 cm within 2 yr.

Adenoma↗
PubMed1993

Design and analysis of studies to reduce the incidence of colon polyps.

Decisions regarding the design and analysis of a phase III study to reduce the incidence of colorectal polyps must take into account two complicating factors: the possibility that polyps are missed during screening exams, and variable lengths of follow-up. In this paper we investigate the effects due to misclassification on the power of statistical tests to detect a change in polyp recurrence rates. We also use Monte Carlo studies to examine the relative efficiency of different methods of adjusting for variable times of follow-up.

Bias↗
PubMed1993

Oral cancer prevention: the case for carotenoids and anti-oxidant nutrients.

The most convincing evidence for a preventive role for any modality is obviously demonstration of incidence reduction produced by that modality. However, cancer prevention trials with cancer incidence as an endpoint have logistic problems rendering them essentially impossible to conduct for most malignancies. Hence a workable strategy often involves analysis of other, indirect lines of evidence to reach conclusions. For oral cancer, dietary epidemiologic evidence points to a protective role for foods rich in carotenoids. Other anti-oxidants, such as vitamin C, are also implicated. Similarly, laboratory evidence points to a carcinogenesis inhibitory role for both retinoids and carotenoids. Clinical studies have targeted premalignant lesions, i.e., oral leukoplakia. For over two decades the efficacy of retinoids, natural and synthetic, has been known. Nevertheless, it has been difficult to translate this into a recommendation for prevention because of the toxicity of retinoids. The synthetic retinoid most often used in these trials is 13-cis-retinoic acid. This compound is toxic even at very low doses (0.1 mg/kg/day), particularly when given over several weeks to months. Hence, although effective, it cannot be advocated for prevention or oral cavity cancer. Studies with nontoxic antioxidants, such as beta-carotene, are much more recent. Early results are promising in that beta-carotene, alone or in combination with other nutrients, can reverse oral leukoplakia without toxicity in short-term trials. Studies currently under way will demonstrate whether durable remissions can be obtained using this strategy. It should be emphasized that such long-term trials are problematic to conduct with the toxic retinoids because the risks of prolonged exposure to them outweighs the chance of cancer development in the usual leukoplakia lesion.

Animals↗
PubMed1991

Expression of the multidrug resistance gene product (P-glycoprotein) in myelodysplasia is associated with a stem cell phenotype.

Previous studies have indicated relative resistance to chemotherapy in the myelodysplastic syndromes (MDS) and associated acute leukaemia. To determine if multidrug resistance may contribute to chemoresistance in these disorders, we studied bone marrow specimens for P-glycoprotein expression (P-GP) by immunocytochemical staining with monoclonal antibodies reactive with cytoplasmic (C219) or surface epitopes (MRK16) of P-GP. Forty-five case specimens from 43 patients were studied, including 32 cases of primary MDS, seven cases of acute myeloid leukaemia (AML) following MDS, and six therapy-related haematological disorders. Cytogenetic analysis was available on 36 specimens. Two staining patterns were detected: (1) cytoplasm and plasma membrane, and (2) staining restricted primarily to the nuclear-cytoplasmic junction. P-GP was detected in seven (22%) cases of primary MDS, four (57%) cases of AML evolving from MDS, and five (83%) cases of therapy-related haematological disorders. Expression of P-GP was restricted to blasts and leukaemic monocytes, and was otherwise absent from terminally differentiated blood cells. Analysis of the relation between P-GP expression and reactivity with the human progenitor cell antigen CD34, revealed a highly significant association (P = 0.001). P-GP reactivity was distributed equally among normal and abnormal karyotypes and did not correlate with specific cytogenetic abnormalities. These findings indicate that multidrug resistance in MDS and karyotypically-related haematological disorders is closely linked to a stem cell phenotype and may contribute to chemoresistance in these disorders.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1990

Prospective study of the frequency and size distribution of polyps missed by colonoscopy.

An important determinant in interpreting the results of colorectal polyp chemoprevention trials is the rate of polyps missed during colonscopic examination. We prospectively examined 90 patients by tandem colonoscopy performed by two alternating examiners. In 69 (76.7%) patients, 221 neoplastic lesions were documented histologically. Of a total of 58 lesions detected in 31 patients, no neoplastic lesion greater than or equal to 10 mm in size was missed; 16% of diminutive (less than or equal to 5 mm) neoplastic polyps and 12.3% of medium-sized (6-9 mm) neoplastic polyps were missed by the first examiner. We conclude that an experienced colonoscopist will miss about 15% of colorectal neoplastic polyps less than 10 mm in size in the setting of adequate bowel preparation. Large (greater than or equal to 10 mm) polyps were rarely missed, however, with the "miss" rate in our study equal to 0, with a 95% confidence limit of 4.64%.

Adult↗
PubMed1990

Epidermal growth factor receptor overexpression and trisomy 7 in a case of Barrett's esophagus.

Increased expression of epidermal growth factor receptor linked with abnormalities of chromosome 7 has been described in a number of malignancies, but not in premalignant lesions. We report on one patient of nine studied with Barrett's esophagus who had trisomy 7 and showed increased expression of epidermal growth factor receptor. Southern blot analysis demonstrated that the protooncogene c-erb-B, which encodes the epidermal growth factor receptor, was not amplified. However, increased expression of the corresponding mRNA was evident on dot blot analysis. Epidermal growth factor (EGF) binding studies were consistent with increased expression of the receptor with approximately 2.3 x 10(5) molecules of EGF bound per cell. These data suggest that chromosome 7 abnormalities can occur in Barrett's esophagus.

Barrett Esophagus↗
PubMed1988

Variability of the thymidine labeling index in squamous cell carcinoma of the head and neck.

Tritiated thymidine (3HTdR) labeling is the standard technique for determining the kinetic activity of tumors. This method has been used to label multiple sections of tumor specimens obtained from seven patients with advanced squamous cell carcinoma of the head and neck. Considerable variability was observed in the labeling index in different sites from the same specimen. To reduce the large sampling error due to heterogeneity, we recommend that an average value be determined from multiple sections when employing this technique.

Carcinoma, Squamous Cell↗
PubMed1987

Neoadjuvant therapy for advanced head and neck cancer with allopurinol-modulated high dose 5-fluorouracil and cisplatin. A phase I-II study.

The combination of cisplatin (100 mg/m2) and 5-fluorouracil (5-FU) by continuous infusion (1 g/m2/day for 5 days) has been reported to produce a high response rate as neoadjuvant therapy for advanced squamous cell head and neck cancer. We sought to improve the response rate by increasing the dose of 5-FU to 1.5 g/m2/day and 2.0 g/m2/day with allopurinol modulation to reduce toxicity. The overall response rate in the 30 patients who received three courses of chemotherapy was 100% with a 50% complete response (CR) rate. A 50% CR rate was observed in patients with T3 (six of 12) and N3 (four of eight) disease. Six patients (four with CR) did not complete subsequent treatment as planned. Seven of 11 (63.6%) chemotherapy complete responders and three of 12 (25%) partial responders (one lost to follow-up) who received all planned treatment are free of disease. The major toxicity encountered was stomatitis (severe in 32%) followed by leukopenia. The maximum tolerated dose of 5-FU in this combination with allopurinol protection was 1.5 g/m2/day. Cisplatin plus high dose 5-FU does not appear to be associated with a higher CR rate than that reported with conventional doses of 5-FU and is more toxic.

Adult↗
PubMed1987

Pulmonary toxicity associated with fludarabine monophosphate.

Fludarabine monophosphate (FAMP), the 2-fluoro, 5' phosphate derivative of 9-beta-D-arabinofuranosyl adenine (ara-A), is a purine nucleoside antimetabolite presently undergoing clinical testing for the treatment of a variety of malignancies including lymphoproliferative disorders and acute leukemia. We report a case of diffuse interstitial pneumonitis during treatment of chronic lymphocytic leukemia with FAMP. This resolved quickly with high dose steroids, recurred with steroid withdrawal, and abated with further steroid therapy. To our knowledge, this is the first reported case of fludarabine monophosphate associated pulmonary toxicity.

Antimetabolites, Antineoplastic↗
PubMed1987

High-dose cytosine arabinoside, daunomycin and 6-thioguanine in relapsed or refractory acute nonlymphocytic leukemia.

Fifteen patients with relapsed (10) or primarily refractory (5) acute nonlymphocytic leukemia were treated with a combination of cytosine arabinoside (3 g/m2 i.v. every 12 h, 12 doses, days 1-6), 6-thioguanine (100 mg/m2 orally every 12 h, 12 doses, days 1-6) and daunomycin (60 mg/m2 i.v. on days 5 and 6 only). Complete remission was achieved in 11 patients. Eight of 10 relapsed patients and 3 of 5 primarily refractory patients entered remission. Median remission duration was 7.5 months (2-36+ months). Ten of the 11 remissions resulted from a single induction course. The time to hematologic recovery was comparable to that seen with 'standard'-dose cytosine arabinoside regimens. Nonhematologic toxicity, although considerable, was not greater than that seen with high-dose cytosine arabinoside alone. The most significant problem was gastrointestinal toxicity with diarrhea occurring in the majority of patients. Mild neurologic toxicity (reversible cerebellar dysfunction) occurred in 2 patients.

Acute Disease↗
PubMed1986

Phase II trial of high-dose continuous infusion 5-fluorouracil with allopurinol modulation in colon cancer.

Twenty patients with metastatic colon cancer without prior chemotherapy received 2 g/m2 of 5-fluorouracil (5-FU) infused over 24 h for 5 days preceded by allopurinol 900 mg orally for 1 week and then continued during, and for 1 week after the infusion was completed. Fourteen patients were evaluable for both response and toxicity. One patient (14%) achieved a partial response lasting 2 months. No significant hematologic toxicity was seen but 18 of 19 patients evaluable for toxicity developed mucositis resulting in dose reductions in 3 patients and refusal of a second course by 2 additional patients. 5-FU infusions with allopurinol as used in this regimen appear to offer no therapeutic advantage over a conventional dosing schedule.

Adult↗
PubMed1986

Failure of allopurinol to provide clinically significant protection against the hematologic toxicity of a bolus 5-FU schedule.

Allopurinol has been shown to ameliorate the myelotoxicity of 5-fluorouracil (5-FU) given as an infusion. To study the potential effectiveness of allopurinol in modifying the toxicity of 5-FU given as a bolus, 8 adult patients with metastatic malignancies were given 11 courses of bolus 5-FU with allopurinol. Allopurinol was administered at a dose of 900 mg/day orally beginning a week prior to the 5-FU therapy and continued a week after the last dose of 5-FU was administered. Three patients received a total of 5 courses of 600 mg/m2 of 5-FU via bolus injection for 4 consecutive days every 28 days. Six patients were given 6 courses of 800 mg/m2 of 5-FU via bolus injection in the same schedule. Gastrointestinal toxicity was mild and no significant neurotoxicity was documented. However, severe myelosuppression occurred at the 800 mg/m2 dosage which led to marked leukopenia in 5 of the 6 patient courses and thrombocytopenia in 1. Gram-negative sepsis developed in 3 of the leukopenic patients with 2 resultant deaths. Allopurinol does not appear to allow clinically significant dose escalation of bolus 5-FU given on this schedule.

Adenocarcinoma↗
PubMed1984

Serum beta 2-microglobulin in the initial staging and subsequent monitoring of monoclonal plasma cell disorders.

Serum beta 2-microglobulin (beta 2-M) measurements were carried out in 97 patients with monoclonal plasma cell disorders. Twenty-six (87%) of 30 patients with monoclonal gammopathy of undetermined significance (MGUS) had increased beta 2-M levels and serial follow-up in seven patients showed a progressive increase with time. Of the 63 patients with active myeloma, pretreatment serum beta 2-M values were available in 25 for correlation with pretreatment stage. Stage III beta 2-M levels were significantly higher than stages I and II (p less than 0.001). Four patients with smoldering myeloma had beta 2-M values similar to stage I disease. There was, therefore, excellent correlation between beta 2-M and myeloma tumor burden. Levels of beta 2-M decreased with response to chemotherapy induction and low levels in stable remission (plateau phase) were associated with unusually good prognosis. Median survival for stage III patients in stable remission with low serum beta 2-M was greater than 48 months. Conversely, at relapse very high beta 2-M levels were associated with a very fulminant and refractory course. Serum beta 2-M, therefore, appears to be an extremely useful marker in initial stratification and follow-up of myeloma patients.

Adult↗
PubMed1983

Reticulocytopenic, coombs' positive anemia induced by procainamide.

A case of Coombs' positive anemia in a man who had procainamide-induced lupus erythematosus syndrome is reported. The patient had a hemoglobin of 4.3 gm/dl and reticulocytopenia (3.1% corrected). Serum lactate dehydrogenase and haptoglobin levels were normal, and total bilirubin was only slightly elevated. Two other reported cases of procainamide-induced hemolytic anemia have demonstrated similar findings. Apparently, procainamide occasionally may induce a reversible, reticulocytopenic, Coombs' positive anemia that is not associated with laboratory evidence of acute hemolysis.

Anemia, Hemolytic↗