Biomedical subjects

E C Krishnan

Publications and source records attributed to E C Krishnan.

At least 19 recordsLinked to original sources

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↗

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↗

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↗

PubMed1990

Radiobiological advantages of an immediate interstitial boost dose in conservative treatment of breast cancer.

Minimum surgery with irradiation is emerging as one of the main modalities of therapy for operable early breast cancer. Between June 1982 and June 1986, 110 breasts with Tis, T1 to T3 lesions have been treated at our institution with lumpectomy and interstitial irradiation to the tumor bed with Iridium-192 perioperatively followed by external beam irradiation. There have been two local recurrences at or near the vicinity of the primary, at a median follow-up of 60 months. To analyze the parameters that might have contributed to the local control, we have examined the treatment volumes, prescribed dose to the tumor bed, dose at the core of the tumor bed, and dose to the surrounding normal tissue. Immediate interstitial implant has the radiobiological advantage of delivering continuous low dose irradiation, immediately upon removal of gross tumor to residual foci. Implantation of the afterloading catheters intraoperatively facilitates accurate dose delivery and avoidance of geographical misses. By precise treatment of any residual foci, immediately upon removal of the gross mass, perioperative interstitial irradiation improves local control and by facilitating less radical surgical excision, leads to better cosmetic results.

Brachytherapy↗

PubMed1989

Treatment options in early breast cancer.

Conservative management of early breast cancer with limited surgical excision and radiotherapy is now being accepted as a viable alternative to mutilating surgical procedures. In this paper, the major steps in the historical development of conservative management are traced, and the results of the current randomized trials are summarized. An innovative method used at the University of Kansas Medical Center delivers a "boost" dose to the tumor bed with interstitial Ir-192 immediately following resection of the primary tumor mass. The results obtained in terms of local control and cosmesis with this technique are presented, and the current state of the art is discussed.

Adult↗

PubMed1988

Immediate effect of irradiation on microvasculature.

The immediate effects of irradiation on microvasculature in muscle in an animal model are described in this paper. By using triple isotopes of 125I, 131I, and 22Na, the transcapillary transfer of albumin from the vascular bed to the extravascular space is determined in terms of mg/g of tissue, after single doses of 2 to 14 Gy. These results reveal an increase in the extravascular albumin immediately after irradiation and suggest an instantaneous compromise in vascular permeability even after 2 Gy. This effect was apparently dose related.

Animals↗

PubMed1988

Cosmetic results in early breast cancer treated with lumpectomy, peri-operative interstitial irradiation, and external beam radiation.

Patients with operable breast cancer were treated at the University of Kansas Medical Center with lumpectomy, peri-operative interstitial Iridium, and external beam radiotherapy, and concomitant adjuvant chemotherapy in a majority of node positive cases. Examination of the cosmetic results in 85 breasts followed for at least 2 years, at a median of 41 months revealed 20% to be excellent, 44% to be very good, 24% good, 9% fair, and 4% to have poor results. In this paper cosmesis is analyzed with reference to the size of the primary, its location, age of the patient, whether the patient received adjuvant chemotherapy, and whether the regional nodes were treated. In this group of patients, the size and the site of the primary, patient's age, and whether adjuvant chemotherapy was administered or not, did not adversely affect the aesthetic outcome. Treatment of the regional nodes gave a worse mean cosmetic score compared to the group in whom only the breast was treated (37.51 vs. 58.98 respectively, p less than 0.001). Among the 11 patients with fair/poor cosmesis, all had regional nodal treatment, 7/11 had inner quadrant lesions, and 7/11 had lesions greater than T1. Further follow-up and accrual would be needed to confirm our results and affirm if other factors would change.

Adult↗

PubMed1987

Perioperative interstitial irradiation in the conservative management of early breast cancer.

Conservation of the breast in early breast cancer with limited resection and radiation is proving to be as effective as modified radical mastectomy in survival and in loco-regional control. Management at the University of Kansas Medical Center consists of an interstitial implant at the time of lumpectomy to facilitate perioperative irradiation with Iridium-192 to the tumor bed. An axillary node dissection is also performed at that time. Two to 3 weeks later external beam irradiation is delivered to the entire breast. One hundred and twenty-three breasts in 120 patients have been treated between June 1982 and June 1986. There were 49 pathological Stage I, 63 Stage II, 8 Stage III carcinomas, and 3 carcinomas in situ, consisting of 72 T1, 43 T2, 5 T3, and 3 TIS lesions. Patients have been followed for a median of 30 months. One patient had a "true" recurrence in the breast. Another patient developed recurrence in a different quadrant. Ninety percent of the patients had good to excellent cosmetic results, 7% were considered fair, and 3% had poor results. Seven patients developed mild arm edema, 4 were found to have moderate edema, and 1 had severe arm edema. Our preliminary results indicate that interstitial irradiation immediately after excision results in excellent local control, with very satisfactory cosmesis and no morbidity due to the simultaneous excision and irradiation.

Adult↗

PubMed1987

Breast conservation treatment with perioperative interstitial irradiation.

Limited resection of the breast combined with radiation has proved to be as effective as more radical surgery in treating early breast cancer. At the University of Kansas Medical Center, the radiotherapy consists of an interstitial implant at the time of lumpectomy to deliver an interstitial boost dose to the tumor bed with iridium-192 immediately following the surgical procedure. An axillary node dissection is also performed at the time of lumpectomy. A dose of 2,000 cGy is delivered to the tumor bed between 40 and 60 h. Two to three weeks later, 4,500-5,000 cGy is delivered to the entire breast with external beam radiation over 5-5.5 weeks. One hundred breasts in 98 patients were so treated between June 1982 and February 1986, with 2 carcinomas in situ, 40 stage I, 51 stage II, and 7 stage III cancers, consisting of 2 TIS, 54 T1, 39 T2, and 5 T3 lesions. Locoregional control with a median follow-up of 31 months was 98%. One recurrence was in a different quadrant, and the other revealed predominantly the in situ component. Immediate implant did not compromise wound healing or cosmesis. The cosmetic result was graded as good to excellent in 88% of the breasts. Our preliminary results appear to suggest a better local control with immediate interstitial irradiation.

Adult↗

PubMed1987

Dose-dependent radiation effect on microvasculature and repair.

It has been postulated that the damage to microvasculature may be a major factor in the manifestation of late radiation damage to organized tissue. In this study, the radiation damage to microvasculature was investigated in a rabbit model during the early phases of irradiation with the use of vascular permeability as a marker. By means of a triple isotopic technique, the vascular, extravascular, and intracellular spaces could be defined. A forelimb and hindlimb of New Zealand White rabbits were irradiated with single doses of 2-30 Gy. 125I- and 131I-labeled bioscreened albumin were used to determine the changes in vascular permeability due to irradiation. The rabbits were sacrificed at various intervals post irradiation. Vascular and extravascular spaces and the respective albumin concentrations in tissue samples from irradiated limbs were compared with control values from the unirradiated contralateral limbs in each animal. The results indicated a definite increase in the vascular permeability of albumin secondary to irradiation. The increase in vascular permeability was apparent instantaneously with irradiation, even at 2 Gy. The microvascular compromise appear to be dose related. When examined at 16-24 hours post irradiation, the excess extravasation of albumin was significant at and beyond 8 Gy. At 10-30 days post irradiation, injury was not apparent up to 15 Gy. Thus there appeared to be an instantaneous injury at the capillary level due to irradiation, which appeared to be dose related. A repair process became evident as early as 16-24 hours and appeared to be dose related as well as related to elapsed time post irradiation.

Animals↗

PubMed1987

Effect of irradiation on microvasculature: a quantitative study.

In clinical radiation therapy, normal tissues and organs are unavoidably irradiated during the course of treatment of neoplastic diseases. Rubin and Cassaret [Clinical radiation pathology. Philadelphia: W.B. Saunders, 1968; Vols 1, 2] have postulated that microvascular damage may be the major contributing factor to late manifestation of radiation damage. It has been theorized that vascular leakage of the protein-rich fluid leads to fibrosis caused by the accumulation of fibroblasts and macrophages. Vascular changes after irradiation have been demonstrated qualitatively. To quantitate the alteration in permeability characteristics at different doses and time-dose fractionations, we have developed an isotopic technique using 125I, 22Na, and 3H2O that allows us to define vascular, interstitial, and intracellular water spaces. Using these values it is possible to quantitate the vascular changes and membrane integrity. Results show that the permeability of the vascular bed is altered by irradiation.

Animals↗

PubMed1986

Electron beam irradiation after reconstruction with silicone gel implant in breast cancer.

Irradiation for breast cancer in the presence of a silicone gel breast prosthesis is sometimes necessary. There is a concern among radiation and other oncologists as to whether the presence of the prosthetic implant would interfere with delivery of the needed irradiation doses. Electron beams, with their finite penetration and rapid fall-off, offer a mode of adequately treating the recurrence and minimizing the radiation to the underlying normal structures, such as the lung and the heart. The dose distribution using 9-20 MeV electrons in the presence of a breast prosthesis is compared to the dose distribution without the implant in a tissue equivalent water phantom. The results reveal no significant difference in the dose delivered due to the presence of the prosthesis. Clinical verification of the dosimetry in the presence of the prosthesis confirmed that the presence of the silicone gel implant does not compromise treatment by irradiation in the management of breast cancer.

Breast Neoplasms↗

PubMed1985

Treatment of renal cell carcinoma with renal infarction, delayed nephrectomy, medroxyprogesterone, and xenogeneic immune RNA.

The authors have used xenogeneic immune ribonucleic acid (RNA) in the treatment of patients with renal cell carcinoma. This has been used in conjunction with renal artery embolization, delayed nephrectomy, and progestational therapy, using immune RNA derived from sheep cell lymphocytes immunized with patient's tumor. Four of 5 patients with Stage I disease had extremely large primary tumors. This group is alive with no evidence of disease at twelve to twenty-four months. There are no Stage II tumors in this group. One patient with Stage III tumor is alive at twenty-two months without evidence of disease. Three patients with metastases are stable at five to twenty-two months. Two patients have progressive disease at three and six months. This treatment has not been effective in patients with massive tumor burden. The results in the other groups are encouraging.

Carcinoma, Renal Cell↗

PubMed1985

In vitro peripheral monocyte culture: possible use as a prognostic indicator for renal cell carcinoma patients.

An in vitro assay was applied to follow 39 patients with renal cell carcinoma. A mononuclear cell-rich fraction was cultured from peripheral blood of patients over a period of 7 days. The number of adherent matured monocytes (macrophages) was analyzed and quantitated at the end of the culture period. Functional activities were analyzed by antibody-coated sheep red blood cells and nonspecific esterase staining techniques. Macrophage yield in patients with detectable tumor burden was 2.06 +/- 2.81 X 10(4) cells/ml blood, and mean values at 3, 6, and 9 months post nephrectomy were 3.67 (n = 21), 6.73 (n = 12), and 9.41 (n = 10) X 10(4) cells/ml blood, respectively. Some of the patients were followed over 30 months. The improvement was significant, and macrophage yield was close to normal values (8.24 +/- 3.14 X 10(4) cells/ml). In the absence of other reliable in vitro assays for these patients, this assay appears to be highly useful in following these patients during the postsurgical period.

Capillaries↗

PubMed1984

Renal cell carcinoma--angioinfarction.

In our experience the mortality rate in 46 patients who underwent angioinfarction for renal cell carcinoma was 4 per cent. Fever, ileus and leukocytosis were noted in 86 to 90 per cent of our patients. The use of absolute ethanol as a medium for renal infarction was associated with a significant incidence of damage to other organs. A 30 per cent decrease in tumor volume following angioinfarction using absorbable gelatin sponge and Gianturco coils was noted in 75 per cent of the patients. There was no evidence of metastatic tumor reduction and we could not document any significant decrease in operative time or blood loss. It would appear that there is some increased survival rate in patients with metastasis who are given adjuvant immune ribonucleic acid therapy. However, the numbers in our series are not significant to draw any definite conclusion. It is apparent that patients treated with infarction, delayed nephrectomy and medroxyprogesterone acetate did not have any significant survival over those treated with palliative nephrectomy or chemotherapy. The macrophage maturation assay may be useful during clinical followup.

Adenocarcinoma↗

PubMed1983

Immune RNA therapy as an effective adjuvant immunotherapy after surgery: an animal model.

Transfer of tumor immunity as adjuvant cancer therapy has been a topic of intense interest. We have examined the efficacy of various combinations of surgery, xenogeneic immune RNA, xenogeneic normal RNA, tumor vaccine, and nonspecific splenocytes as adjuvant therapy for B16 melanoma in the C57BL/6J mouse system. B16 melanoma was transplanted by trocar into the right hind limb of 6-week-old mice. The tumors were readily palpable on the ninth day posttransplantation. The tumors were amputated at that time under mild anesthesia. Immune RNA was prepared by hot phenol extraction from immune sheep spleens. Various combinations of immune RNA, normal RNA, and tumor antigen, with or without normal mouse spleen cells, were administered every other day for a total of 10 injections. The survival and mode of death was followed up to 120 days. All mice without any treatment died within 30 days. Immunotherapy had no effect on the survival of mice that did not have surgical therapy. Individual group comparisons between mice that underwent surgery only and mice that had surgery plus immune RNA immunotherapy revealed a striking statistical improvement (P less than 0.01). Comparing all groups that received amputation plus various combinations of adjuvant immunotherapy showed no statistical difference in survival. However, immune RNA appears somewhat superior to normal RNA or antigen only. It appears that adjuvant immune RNA immunotherapy following surgical excision in the B16 melanoma model significantly improves survival and retards the spread of metastases.

Adjuvants, Immunologic↗

PubMed1983

Culture of peripheral monocytes in vitro in patients with renal cell carcinoma: a possible prognostic indicator.

An in vitro assay has been applied in 23 patients with renal cell carcinoma. A mononuclear cell-rich fraction was cultured from peripheral blood of patients with renal cell carcinoma. The number of monocytes maturing into macrophages was quantitated over a period of 7 days. Monocyte maturation was significantly lower in patients with renal cell carcinoma than in normal individuals. Of 10 patients tested both pre- and post-nephrectomy, 8 patients showed clinical improvement after surgery. In all 8, the posttreatment macrophage yield improved significantly from the pretreatment values to approach normal values. In 2 patients found to have metastasis postoperatively, the macrophage yield continued below normal levels. Our results suggest that the in vitro maturation of macrophages from mononuclear cells may parallel clinical events.

Adenocarcinoma↗