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Biomedical subjects

L Krishnan

Publications and source records attributed to L Krishnan.

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

Recruitment with high physiological doses of estradiol preceding chemotherapy: flow cytometric and therapeutic results in women with locally advanced breast cancers--a Southwest Oncology Group study.

One theoretical method of increasing chemotherapeutic efficacy in breast cancer is to temporarily increase the number of tumor cells in cycle through hormonal recruitment prior to initiation of chemotherapy. In an effort to determine when and if this could be reliably accomplished, 50 women with locally advanced and/or metastatic breast cancer with known estrogen receptor (ER) status were entered into a serial breast biopsy study designed to measure increases in S-phase fraction (SPF) and proliferative index (PI; S + G2 + M) following administration of a high physiological dose of estrogen via estradiol vaginal suppositories prior to chemotherapy. Blood levels of estradiol were maintained in a range (0.5-5 nM) known to increase SPF in vitro. Compliance with suppository administration was monitored by serial blood sampling. Tumors were sampled at 0, 24, 48, 72, and/or 96 h. Thirty-one ER-positive and 9 ER-negative women had evaluable baseline biopsies and at least 1 subsequent biopsy. An increase was seen for SPF in 20 (69%) and for PI in 23 (79%) of 29 ER-positive patients at 48 h after estrogen initiation (95% confidence intervals, 49-85% for SPF and 60-92% for PI); similar increases were seen at 72 h. Median baseline SPF and PI values in ER-positive patients for whom increases were noted at 48 h were 6.2 and 8.5%, respectively. The median relative increases in these patients were 170 and 100%, respectively, at 48 h. The increases observed at 24 h in 4 (SPF) and 6 (PI) of the 9 ER-negative patients could have occurred by chance alone. Twenty-five of the 28 locally advanced (T4 and/or N2-3) patients achieved a complete response during combined modality treatment (estradiol-chemotherapy, mastectomy, and radiation). At a minimum follow-up time of 42 months, estimated 5-year progression-free and overall survivals are 30 and 49%, respectively, with a median time to progression of 35 months. Twenty-two women had metastatic disease (19 also had locally advanced disease). Thirteen had a complete or partial response, with a median duration of 12 months. Median progression-free and over-all survival times for all metastatic patients are 4 and 17 months, respectively. Estimated 5-year survival for metastatic disease patients is 27%. A high physiological dose of estrogen administered to patients with locally advanced ER-positive tumors can reliably increase the tumor SPF and PI within 48 h.(ABSTRACT TRUNCATED AT 400 WORDS)

Breast Neoplasms↗
PubMed1994

Neonatal tuberculosis: a case report.

A 3-week-old baby with neonatally acquired tuberculous bronchopneumonia is presented. The diagnosis was considered because the neonate did not respond to conventional management of bronchopneumonia. The importance of including tuberculosis as a differential diagnosis in respiratory disorders, especially in developing countries, is emphasized.

Bronchopneumonia↗
PubMed1994

Quantitative assay for the radiosensitivity of malignant melanomas.

There exists a controversy regarding the radiosensitivity of malignant melanomas. Several in vitro and in vivo studies have suggested that the 'radioresistance' of melanomas may be due to a 'large shoulder' on the cell survival curve. As yet, however, there is no consensus relating to the effects of total dose, the fraction size and the time between fractions. In this study, we have used a B16 mouse melanoma model to evoke a response with single doses of irradiation, and have attempted to evaluate the growth kinetics of in vivo irradiated and unirradiated tumour cells implanted in an unirradiated limb. The radiosensitivity of B16 melanoma cells was quantified by comparing the growth of tumour from an inoculum of 10(6) melanoma cells irradiated in vivo with various doses of radiation to the growth of tumour following inoculae of 10(3) to 10(7) cells derived from unirradiated melanoma. Using this bioassay we found that a single dose of 18 Gy leads to close to 99% of the surviving cells becoming nonclonogeneic. It is hoped that this assay will further the development of the most efficacious fractionation scheme in the treatment of malignant melanomas.

Animals↗
PubMed1994

Perioperative implantation of iridium-192 as the boost technique for stage I and II breast cancer: results of a 10-year study of 655 patients.

PURPOSE: To assess the efficacy of perioperative implantation of iridium-192 for stage I and II breast cancer. MATERIALS AND METHODS: The authors retrospectively reviewed findings from 655 patients with stage I and II cancer treated with conservative surgery and Ir-192 implantation between 1982 and 1992. Hollow plastic tubes were placed in the tumor bed as a single- or double-plane implant at lumpectomy. Ribbons with Ir-192 seeds were inserted into the tubes 4-6 hours later. The Ir-192 was left in place for approximately 50 hours. External-beam irradiation was given to the whole breast 10-14 days later. RESULTS: Follow-up ranged from 2 to 146 months. The local control at 10 years for stage I and II disease was 93% and 87%, respectively. The 10-year actuarial survival rate was 92% +/- 1 for stage I disease and 72% +/- 4 for stage II disease. The rate of survival with no evidence of disease for stage I and II disease combined was 82% +/- 1 at 5 years and 75% +/- 3 at 10 years. CONCLUSION: Perioperative implantation produced excellent local control equal to that with electron-beam therapy.

Brachytherapy↗
PubMed1994

The role of radiotherapy in the treatment of breast cancer: results of perioperative implantation.

Between 1982 and 1993, 620 of 938 patients with pathologically staged I-II breast cancer were treated at the time of reexcision (perioperatively), with an iridium-192 (Ir-192) implant to the tumor bed to give 2000 cGy to the 30 to 40 cGy/ph isodose line. This was followed by 4500 cGy to the entire breast at 180 cGy/d for 25 fractions. The local control for the 620 patients at 5 and 10 years was 93 and 89%, respectively. The actuarial survival at 5 and 10 years was 92 and 81%. The cosmetic results were good to excellent for 87% of the patients. Chemotherapy had no impact on local control in this study. Ir-192 implant is especially useful for deep tumors, making possible more flexibility in the techniques used to boost the tumor volume. Perioperative implantation has increased the accuracy of placing the boost dose, shortened the overall treatment time, and, for some patients, eliminated the need for rehospitalization and anesthesia.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1993

Propranolol has direct antithyroid activity: inhibition of iodide transport in cultured thyroid follicles.

The effect of propranolol on the process of thyroid hormone formation was studied in a physiological culture system. Porcine thyroid follicles were preincubated with propranolol for 24 h. Iodide transport, iodine organification, and de novo thyroid hormone formation were measured by incubating these follicles with the mixture of carrier-free 0.1 microCi Na125I and 50 nM NaI for 2 to 6 h at 37 degrees C. A concentration of propranolol greater than 100 microM inhibited iodide transport in a dose-dependent manner; this inhibition was non-competitive with iodide and independent of thyrotropin (TSH). Reduced iodine organification and thyroid hormone formation was seen with 150 microM propranolol or greater. The inhibitory action of propranolol was not caused by beta-blocking activity, since D-propranolol (devoid of beta-blocking activity) inhibited iodide transport, and other beta-blockers (metoprolol, atenolol, and labetalol) did not inhibit iodide transport. The inhibition of iodide transport was most likely caused by membrane stabilizing activity since quinidine, which possesses the same membrane stabilizing activity as propranolol, also inhibited iodide transport. TSH-mediated cAMP generation and Na+K+ ATPase activity, membrane functions for iodide transport, were unaffected by propranolol. Our study has shown, for the first time, that propranolol has a direct antithyroid action, namely inhibition of iodide transport in the intact thyroid follicle.

Adrenergic beta-Antagonists↗
PubMed1993

Suppression of local and systemic GVHR by supernatants from human choriocarcinoma cell lines.

Graft versus host reaction (GVHR) and host versus graft reactivity during pregnancy share at least some cellular pathways. Immunosuppression mediated by placental suppressor factors may actively contribute to the survival of the conceptus in the immunocompetent mother. We have previously reported that supernatants from human choriocarcinoma cell lines inhibit mitogen-activated and antigen-activated proliferation of lymphoid cells. From this perspective, we investigated the capacity of supernatants from human choriocarcinoma cell lines (HCS) to suppress in vivo graft versus host reactions in mice. HCS was tested for its ability to block both local as well as systemic GVHR induced by the injection of parental cells into F1 mice. HCS mediates profound suppression of acute and chronic GVHR. These results confirm that human choriocarcinoma cell lines secrete a potent immunosuppressive factor(s) which can efficiently modulate immune responses in vivo.

Animals↗
PubMed1993

Preservation of augmented breasts in patients with breast cancer.

It is not uncommon for a patient who has previously undergone breast augmentation to be diagnosed with breast cancer. The options available to such a patient are a modified radical mastectomy and breast conservation treatment. If the patient chooses breast conservation treatment, the concerns that need to be addressed are whether the breast prosthesis should be removed before irradiation and whether the presence of the prosthesis would impair local control of the tumor or cosmetic results. This article presents the feasibility of breast conservation treatment without impairing the augmentation. Five patients underwent lumpectomy, perioperative placement of interstitial catheters in the tumor bed for immediate postoperative boost brachytherapy, and external beam irradiation to the entire breast. Results of follow-up examinations for a median of 60 months revealed successful local control and satisfactory cosmetic results. No long-term effects of radiation therapy on the breast prostheses have been observed. Thus, it seems feasible to conserve the breast and the augmentation with limited surgical resection and radiation therapy, including an immediate interstitial boost.

Adult↗
PubMed1993

Early-stage breast cancer: local control after conservative surgery and radiation therapy with immediate interstitial boost.

Two hundred forty-five women (250 breasts) with early-stage breast cancer were treated between June 1982 and June 1990 with lumpectomy, immediate (boost) interstitial iridium-192 to 15-20 Gy, and external-beam irradiation to the entire breast to 45-50 Gy. There were 123 stage I cancers (T1N0M0), 123 stage II cancers (36 T1N1, 50 T2N0, 33 T2N1, four T3N0), and four stage III cancers (two T2N2, two T3N1). At a median follow-up of 69 months (range, 26-122 months), there were 14 recurrences in the treated breasts. Four were at the site of primary disease, eight were in other quadrants, and two were in both. With immediate interstitial boost, the 11-year actuarial recurrence rate in the breast is 7.7% and the recurrence rate at the site of primary disease is 3.2%.

Adult↗
PubMed1993

Prostate cancer: results of external irradiation.

From 1975 to 1982, 205 patients with local prostate cancer were treated at the radiation oncology department, the University of Kansas Medical Center, Kansas City, Kansas. Patients' median age was 73 years. All of the patients were staged according to American Urologic staging criteria. Twenty-eight patients had stage A2 cancer, 91 patients had stage B cancer, and 86 patients had stage C cancer. All patients were treated using megavoltage radiation (dosage range: 6000 cGy to 7100 cGy). The follow-up period ranged from a minimum of 8 years to a maximum of 15 years (median: 9.4 years). The clinical local control was 96% for stage A2, 94% for stage B, and 90% for stage C disease. The overall and disease-free survival rates were 71% and 60%, respectively. Fourteen patients developed moderate complications with one patient (0.5%) requiring surgical intervention. The local control and survival rates reported in this study are comparable with surgical results, suggesting that external beam irradiation in prostate cancer is safe and effective.

Adult↗
PubMed1992

Management of advanced squamous cell carcinomas of the maxillary sinus.

From 1970 to 1988, 41 cases of advanced maxillary sinus cancers were treated at the University of Kansas Medical Center. Local control for the 37 evaluable patients was achieved in 21 (57%). Local control by radiation therapy alone was achieved in ten of 19 (53%) patients compared with eight of 14 (57%) treated with a combination of surgery and radiation therapy. A dose greater than 6500 cGy correlated with better local control in patients treated with radiation therapy alone. Neck node failure occurred in three of 35 (8%) patients when not electively treated. Neck metastasis either at presentation or at a later stage reduced survival. The overall absolute survival for the entire group at 5 years was 35%. A combination of preoperative radiation therapy and surgery is recommended for patients with advanced-stage maxillary sinus cancer. Radiation therapy is an equally good alternative for those who are not surgical candidates or refuse surgery.

Aged↗
PubMed1992

Breast cancer with extensive intraductal component: treatment with immediate interstitial boost irradiation.

Extensive intraductal component (EIC) has been reported to have a prominent role in local recurrence after treatment of early-stage breast cancer with lumpectomy and irradiation. Pathologic specimens from 250 breasts (245 patients) treated between June 1982 and June 1990 with lumpectomy, immediate (boost) interstitial iridium-192 to 15-20 Gy, and external-beam irradiation to the entire breast to 45-50 Gy were reviewed. EIC was present in 61 breasts. At a median follow-up period of 58 months (range, 14-110 months), there were 10 recurrences in the 250 treated breasts. Of these 10, three were in patients from the group with EIC. The 10-year actuarial recurrence rates in breasts with and without EIC were 9.1% and 5.2%, respectively. The difference between the two rates was not significant. If an immediate boost with interstitial iridium is used in therapy, the influence of EIC on local failure is insignificant.

Adult↗
PubMed1992

Computerised neonatal case records: a four year experience.

A computerized system for neonatal case records has been used for the last four years at Kasturba Hospital. The software was developed in-house. The data base can be used to generate discharge summaries, neonatal statistics and epidemiological information. For a single patient, entry of data and printing of the discharge summary takes four to five minutes. Consolidated demographic and epidemiological statistics or selective clinical data for clinical research is easily retrievable. The system is efficient, accurate and easy to operate.

Humans↗
PubMed1991

In vitro and in vivo immunosuppressive effects of supernatants from human choriocarcinoma cell lines.

Local immunosuppression mediated by placental suppressor factors may contribute to the absence of consistently demonstrable cellular immunity against the fetus. In this context, we have investigated the immunosuppressive capabilities of supernatants from human trophoblastic choriocarcinoma cell lines (HCS) by testing the effects of HCS on immune responses in vitro and in vivo in the human and murine systems. HCS suppresses mitogen-induced proliferation and mixed lymphocyte reactions in humans and in mice, as well as antigen-induced T cell proliferation in mice. HCS also suppresses the in vivo response of mice to allogeneic cells. Furthermore, HCS when injected intraperitoneally causes the induction of suppressor cells in mice which in turn prevent the mounting of an allogeneic response in other strains of mice. These results indicate that human choriocarcinoma cell lines secrete a suppressor factor(s) which induces suppression in vitro as well as in vivo through the generation of suppressor cells.

Choriocarcinoma↗
PubMed1991

A review of the role of radiation therapy in the treatment of patients with breast cancer.

Irradiation has been used to treat cancer of the breast since 1895. Over the period between 1895 to the present, the therapeutic use of irradiation has evolved from a cauterizing agent to a sophisticated use of theory and practice to cause tumor cell death while at the same time producing maximum normal tissue sparing. The use of radiation has made it possible for the surgeon to use conservative breast sparing surgery to obtain excellent cosmetic results, while at the same time producing a local control equal to that of mastectomy. For the patient, conservative surgery becomes a better option than mastectomy because it not only produces local control equal to that of mastectomy, but gives the wonderful added benefit of a more superior and pleasing cosmetic result.

Antineoplastic Agents↗