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K Dhingra

Publications and source records attributed to K Dhingra.

48 records · Page 3Linked to original sources
PubMed1991

Hybridization protection assay: a rapid, sensitive, and specific method for detection of Philadelphia chromosome-positive leukemias.

The Philadelphia (Ph1) chromosome is present in greater than 90% of patients with chronic myelogenous leukemia (CML) and in 2% to 20% of those with acute leukemias, for which it is an important prognostic marker too. The chimeric BCR-ABL mRNAs resulting from the translocation encode either a 210-Kd or a 190-Kd protein. The techniques used to detect Ph1 chromosome include karyotyping, Southern analysis to demonstrate bcr rearrangement, and polymerase chain reaction to amplify the BCR-ABL transcripts. However, the routine performance of these methods by clinical laboratories is cumbersome, time consuming, and exposes laboratory personnel to radioisotopes. We describe here the clinical application of a new method, the hybridization protection assay (HPA), which uses chemiluminescent acridinium-ester-labeled probes in conjunction with PCR for detection of the amplified BCR-ABL sequences. The method is sensitive, specific, and can reliably distinguish between the transcripts for P190BCR-ABL and P210BCR-ABL. In contrast to the 2 days or longer required for conventional hybridization, HPA analysis can be completed in less than 30 minutes. We have successfully used this method to analyze 60 leukemia samples (34 from Ph1-negative acute leukemias; 6 from Ph1-positive acute leukemias; and 20 from CML) with complete correlation (of BCR-ABL positivity or negativity) with the results of karyotype or Southern Blot analysis of genomic DNA for bcr rearrangement. Therefore, the HPA, in conjunction with PCR, appears to provide a rapid and reliable test for the diagnosis of Ph1-positivity.

Humans↗
PubMed1991

A phase I trial of recombinant alpha-2a interferon (Roferon-A) with weekly cisplatinum.

Eighteen patients with advanced solid tumors were treated in a phase I study of cisplatinum in combination with recombinant alpha-2a interferon (Roferon-A, Hoffman-LaRoche, Inc, Nutley, NJ). Roferon-A was administered at a dose of 5 MU/m2 S.C. three times a week and the dose levels of cisplatinum were 15, 20, 25, 33, and 42 mg/m2/week given intravenously. All patients experienced grade I/II fatigue, nausea and vomiting. Grade III toxicity occurred in 4/6 patients at dose level 4. The dose limiting toxicities were myelosuppression [leukopenia (two patients), neutropenia (one patient), thrombocytopenia (one patient)], vomiting (one patient) and severe fatigue leading to a decrease in performance status (one patient). One patient with non-small cell lung carcinoma had a mixed response and another a minor response. The recommended dose level of this combination for phase II studies is cisplatinum 25 mg/m2/week and Roferon-A 5 MU/m2 three times a week.

Adult↗
PubMed1991

Appearance of acute leukemia-associated P190BCR-ABL in chronic myelogenous leukemia may correlate with disease progression.

The Philadelphia translocation in chronic myelogenous leukemia (CML) results in the production of a 210 kD BCR-ABL protein. In contrast, in 50% of Philadelphia-positive acute leukemias, the translocation results in the production of a 190 kD BCR-ABL protein. To investigate the hypothesis that the production of P190 may be associated with the progression from chronic phase to blast crisis in CML, we used polymerase chain reaction to analyze blood from 37 patients with accelerated phase/blast crisis CML for the transcripts coding for the P210BCR-ABL and P190BCR-ABL. The mRNA encoding for P210 was detected in all patients. In three patients, mRNA encoding both P210 and P190 was present. In two of these three patients, samples were available from the time of initial diagnosis. Analysis of these samples did not reveal any transcripts for P190. We conclude that in some patients the appearance of P190BCR-ABL may correlate with transformation to a more aggressive, terminal phase of CML.

Adolescent↗
PubMed1989

Oncogene expression and cytotoxic activity of tumor necrosis factor against human cancer cells.

We studied the effect of recombinant tumor necrosis factor (TNF) on selected leukemic and breast cancer cell lines. Based on their sensitivity to TNF in the presence or absence of cycloheximide (CHX), these cell lines could be categorized into three phenotypes: SS, cells that are spontaneously sensitive to TNF; RS, cells that are normally resistant to TNF but are killed in the presence of CHX; and RR, cells that are resistant to TNF irrespective of the presence of CHX. The effect of TNF on expression of c-myc, N-ras, and Ha-ras oncogenes was also studied in these cell lines. Transient, minimal suppression of c-myc was observed in one cell line (Raji), and an inconsistent stimulation of c-myc in another (MCF-7.OCI). No correlation was observed between the effect on oncogene expression and TNF sensitivity.

Adenocarcinoma↗
PubMed1988

Transient bone marrow aplasia associated with non-A, non-B hepatitis.

We describe two patients who developed aplastic anemia early in the course of non-A, non-B hepatitis. Spontaneous rapid recovery of bone marrow function occurred in both patients. Although early bone marrow transplantation has been recommended as the treatment of choice in hepatitis-associated aplastic anemia, these patients illustrate the need for a period of expectant observation before undertaking bone marrow transplantation in such patients.

Adolescent↗
PubMedDate not supplied

Pathologic tumor response in the breast following neoadjuvant chemotherapy predicts axillary lymph node status.

PURPOSE: Neoadjuvant chemotherapy is becoming the standard of care for locally advanced breast cancer. This study was performed to determine whether pathologic primary tumor response to neoadjuvant chemotherapy might predict axillary lymph node status and so be used to identify patients in whom surgery could be effectively limited to biopsy of the previous primary tumor site without axillary dissection. PATIENTS AND METHODS: Between 1992 and 1996, 170 consecutive patients with locally advanced breast cancer were treated in a prospective trial with four preoperative cycles of 5-fluorouracil, doxorubicin, and cyclophosphamide. Disease was staged before initiation of preoperative chemotherapy and before surgery. Segmental resection with axillary lymph node dissection or modified radical mastectomy was performed first, followed by postoperative chemotherapy and radiation therapy of the breast (or chest wall) and regional lymphatics. Patient and tumor characteristics associated with complete versus incomplete pathologic primary tumor response to neoadjuvant chemotherapy and correlation between primary breast tumor pathologic response and axillary lymph node status found at surgery were analyzed. RESULTS: Of 156 evaluable patients, 30 patients (19%) had primary breast tumors that were completely eliminated after induction chemotherapy based on histologic assessment. Nineteen of those 30 patients (63%) had negative axillary lymph nodes at dissection, compared with 13 patients (33%) of the 40 who had a near-complete pathologic primary tumor response (< or = 1 cm3 remaining) and only 15 patients (17%) of the 86 who had > 1 cm3 tumor remaining in the pathology specimen of the breast primary. Of the 22 patients with a complete pathologic response in the breast and a clinically negative axilla after induction chemotherapy, axillary dissection revealed positive lymph nodes in four. These four patients had only one or two positive lymph nodes. DISCUSSION: Because initial clinical regression of primary tumor with neoadjuvant chemotherapy is considered an excellent prognostic indicator and because patients with locally advanced breast cancer routinely receive local and regional radiation treatment followed by additional chemotherapy, the role of breast and axillary surgery has been questioned. In this study, a complete pathologic response of the primary tumor to induction chemotherapy is highly predictive of negative axillary lymph node status. Therefore, axillary lymph node dissection may be omitted in certain subsets of patients who have a biopsy-proven complete pathologic response in the primary tumor and a clinical negative axillary examination. Further prospective, randomized investigation is needed to confirm this finding.

Adult↗