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K Dowlatshahi

Publications and source records attributed to K Dowlatshahi.

14 recordsLinked to original sources
PubMed1992

Histologic evaluation of rat mammary tumor necrosis by interstitial Nd:YAG laser hyperthermia.

The extent of coagulative necrosis caused by interstitial laser hyperthermia was measured for different quantities of laser energy in a rat mammary tumor model. Continuous wave Nd:YAG laser at a power level of 5 W was focused onto a 600 mu diameter bare tip quartz fiber and placed inside a 19-gauge needle, which allowed the para-axial flow of normal saline at 1 cc/min. A microthermocouple soldered to the outside of the probe continuously provided the interstitial temperature. After the probe was inserted into the tumor, it was withdrawn as laser energy was administered at a rate sufficient to maintain the temperature within 42-45 degrees C. Tumors were excised after 48 hours, fixed in formalin, cut in 3 mm slices, and the coagulated surfaces measured microscopically. Laser fiber transmission loss was 1% per 1,000 J of laser energy and the average time required to coagulate 1 cc of tumor was 2 minutes. There was a statistically significant correlation between the volume of tumor necrosis and the level of laser irradiation (r = 0.71, P less than 0.001). It is concluded that the described technique is an efficient method of tumor coagulation by interstitial laser hyperthermia and proportionally larger volumes of necrosis are created with greater amounts of laser energy.

Adenocarcinoma↗
PubMed1992

Percutaneous interstitial laser therapy of a patient with recurrent hepatoma in a transplanted liver.

We report in situ treatment, by focal hyperthermia, of a recurrent hepatoma in the transplanted liver of a 53-year-old man. Hyperthermia was generated by neodymium-yttrium-aluminum-garnet laser, which was delivered through a fiber placed inside a 19-gauge needle and inserted percutaneously into the liver under ultrasound guidance. The effect was monitored in real time by ultrasound and subsequently confirmed by computerized tomography and needle core biopsy. Objectively the tumor growth was halted for 3 months, indicating partial response to this minimally invasive treatment.

Carcinoma, Hepatocellular↗
PubMed1991

Nonpalpable breast lesions: findings of stereotaxic needle-core biopsy and fine-needle aspiration cytology.

Two hundred fifty mammographically detected nonpalpable breast lesions suspicious for malignancy in women who underwent routine screening mammography were stereotaxically localized. Fine-needle-aspiration (FNA) cytologic specimens and needle-core biopsy specimens were obtained before open biopsy in every case. Seventy-six lesions (30.4%) were malignant. Sixty-three (83%) of these 76 cancers were 1 cm long or smaller. Needle-core biopsy alone was used to diagnose conclusively 41% (n = 31) of these cancers, while FNA cytologic study alone was used to diagnose 32% (n = 24). No false-positive results occurred with either test. The same diagnosis was reached in 54% (n = 41) when the combined results of both needle tests were considered. In applying the two needle tests to 125 mammographically defined low-suspicion lesions, 85 (68%) were found to be benign by means of either one or both needle tests; there was one lobular carcinoma in situ. By applying this algorithm, 85 (34%) of 250 patients with abnormal mammograms, or one-third of all patients recommended for open biopsy, might have avoided surgery.

Adult↗
PubMed1991

A prospective study of double diagnosis of nonpalpable lesions of the breast.

Approximately three-fourths of open biopsies of the breast performed for mammographically detected suspicious lesions are shown histologically to be benign. Under the narrow conditions described herein, stereotaxic fine-needle aspiration (FNA) can identify these lesions with an accuracy of more than 90 per cent and a false-negative rate of 5 per cent. In an effort to reduce this failure rate, the mammographic appearance and stereotaxic FNA results of these lesions each were given scores on a scale of zero (benign) to five (malignant), to derive an over-all risk score prospectively applied to 264 suspicious occult lesions of the breast prior to open, biopsy. While all 264 lesions could be assigned a mammographic score, adequate tissue for assignment of a cytologic score could be obtained from 150 lesions. Of the 150 evaluable lesions, 53 were malignant and 97 were benign, historically. With a total score of two as the threshold for open biopsy, 21 of 150 (14 per cent) were proved to be benign, with no false-negative findings. If the total threshold score mandating an open biopsy was raised to four, the comparable figures were 61 of 150 (40 per cent) benign lesions and two false-negative instances of carcinoma in situ. Provided adequate tissue is aspirated for cytologic examination, we conclude that this algorithm has practical value in the management of nonpalpable lesions of the breast in that it can reliably identify a fraction of the benign lesions and spare these patients an operation.

Algorithms↗
PubMed1990

Protection of fiber function by para-axial fluid flow in interstitial laser therapy of malignant tumors.

In the past, interstitial laser therapy frequently has failed because of the damage to the bare fiber tip due to intense heat generated at the point of contact. Using a rat mammary tumor model, we describe a method of placing a 600 micron fiber inside a gauge 19 needle cannula after its insertion into the tumor. With this device continuous wave Nd:YAG laser is delivered to the target tumor while 0.9% saline flows para-axially into the tumor. Significant coagulation necrosis was induced with 500 joules at 5 watts, 100 seconds and 1 cc per minute of saline while the needle-fiber is pulled out of the tumor by 10 mm. The mean transmission loss after 500 joules was 2% in ten experiments. The tumor edema due to 1.5 ml of saline was transient. We conclude that successful hyperthermic coagulation necrosis by Nd:YAG laser can be achieved with minimal transmission loss by employing the above technique.

Animals↗
PubMed1989

Therapeutic effect of N-(4-hydroxyphenyl)retinamide on N-methyl-N-nitrosourea-induced rat mammary cancer.

Virgin Sprague--Dawley rats received a single i.v. injection of 40 mg N-methyl-N-nitrosourea (MNU)/kg body wt. at 50 days of age. After the first palpable mammary tumor reached 10 mm in size, the animals were sequentially allocated to one of 4 groups: (I) placebo diet, (II) 10 micrograms tamoxifen s.c. 3 times per week, (III) 3 mmol N-(4-hydroxyphenyl)retinamide (4-HPR)/kg diet, or (IV) both (II) and (III). Weekly measurements of initial tumors and subsequent tumors were made throughout the study. 4-HPR administration resulted in a complete regression (non-palpable state) of the first mammary tumor in 6 animals (22%) and partial regression or nonprogression in 5 others (19%). Tamoxifen alone induced only partial response in 9 animals (33%). 4-HPR and tamoxifen resulted in 19% total and 26% partial response. The data suggests therapeutic value of 4-HPR in MNU-induced rat mammary carcinoma.

Adenocarcinoma↗
PubMed1989

Nonpalpable breast tumors: diagnosis with stereotaxic localization and fine-needle aspiration.

Modern mammography is the most effective means of detecting nonpalpable breast cancers, but correct diagnosis for malignancy is made in only 20%-30% of the cases. The conventional method of lesion localization usually results in approximate placement of the hookwire in the breast. The authors report the results of stereotaxic localization, combined with fine-needle aspiration and cytologic study, performed in 528 cases. Clinically occult breast lesions were localized precisely (within 2 mm 96% of the time), sampled by means of a 23-gauge needle, and marked with either methylene blue or a hookwire for subsequent open excisional biopsy. The results indicate a sensitivity of 95%, specificity of 91%, and accuracy of 92% for the fine-needle aspiration procedure. This technique offers a significantly improved preoperative method of diagnosing small breast lesions with minimal pain, no complications, reduced cost, and no disfigurement or scar interfering with subsequent mammographic follow-up.

Biopsy, Needle↗
PubMed1987

Cytologic diagnosis of occult breast lesions using stereotaxic needle aspiration. A preliminary report.

In mammographically detected breast lesions, only 10% to 25% of biopsy specimens are malignant. Furthermore, the current method of needle localization of these lesions is cumbersome and inefficient. Stereotaxic needle aspiration was used to examine 84 patients. Successful localization with the needle tip within 1 to 2 mm of the suspected lesion was possible in 80 cases (95.2%). Following aspirate cytology, the lesion was localized with indigo carmine and Kopans' wire and every patient underwent a standard open excisional biopsy. Twelve cases of breast cancer were diagnosed histologically. Eleven of these cases were correctly diagnosed cytologically, while one case yielded a false-negative result. In the remaining 72 histologically benign cases, four lesions were reported cytologically to be atypical. There were no complications. Stereotaxic needle aspiration localizes occult breast lesions precisely and in conjunction with mammography, and it is an acceptable preoperative method of diagnosing nonpalpable breast tumors.

Biopsy, Needle↗
PubMed1986

Stereotaxic needle localization and cytological diagnosis of occult breast lesions.

A stereotaxic technique for localization of occult breast lesions and fine needle aspiration for cytological diagnosis was used on examination of 543 patients. Successful localization with the needle tip within 1 mm of the suspected lesion was possible in 490 patients (90.2%). Based on a high mammographic index of suspicion for malignancy, 187 of 490 patients were selected to undergo open biopsy, following aspiration cytology and localization with methylene blue injection. The statistical results (cytologic vs. histologic examination) revealed a sensitivity of 97.5% and a specificity of 95.2% for cytologic diagnosis of occult breast lesions. The technique is easy to learn and takes 20-30 minutes to perform. Compliance was 100% and complications were nil. This new technique expedites localization and maximizes the specificity of mammography for occult breast lesions.

Biopsy, Needle↗
PubMed1979

Immunoregulatory properties of human esophageal tumor extract.

Noncytotoxic aqueous extracts of esophageal tumors (TEx) inhibit the spontaneous uptake of 3H-thymidine by human peripheral blood mononuclear cells (PBM). TEx also inhibits mitogen- and antigen-induced PBM blastogenesis, mitogenesis, 3H-thymidine uptake, and 3H-leucine incorporation. Inhibition is reversible and is mediated by a heat-labile protein with a m.w. of approximately 70 to 80,000 daltons. Inhibitory activity is not due to trivial binding of mitogen or neucleotide by the inhibitor, nor is it entirely tumor specific since similar but quantitatively less activity is extractable from adjacent normal esophageal mucosa. Assorted cell surface membrane phenomena such as contact inhibition of in vitro endothelial cell proliferation, lymphocyte E rosette formation, and cap formation are unaffected by TEx. In contrast, immunoglobulin synthesis by pokeweed mitogen-stimulated PBM is enhanced by TEx. The potential importance of the local production of immunoregulatory agents like TEx in the immunologic control of tumor cell growth is discussed.

Cell Membrane↗
PubMedDate not supplied

Colorectal carcinomas: diagnostic implications of their changing frequency and anatomic distribution.

This retrospective review included 1,694 consecutive cases of colorectal carcinoma diagnosed at the University of Chicago Medical Center during a 25-year period (1960 through 1984). The number and percentage of tumors occurring within 7 anatomic segments of the large bowel were determined. The statistical data for a recent 5-year interval were then compared with those of the 2 preceding decades. There was a 10.2% increase in the frequency of cancers originating in the cecum or ascending colon, while rectal and rectosigmoid carcinomas declined by 15.8% during the same study period. These data provide further evidence for a progressive left-to-right shift in cancer distribution within the colon during the past quarter century. Currently, the most proximal and distal 20-25 cm segments of the large bowel (cecum or ascending colon versus rectum and rectosigmoid) each harbor approximately 25% of the tumors. Therefore, the classic medical teaching that over 50% of colorectal cancers would be detectable by digital examination and/or proctosigmoidoscopy is no longer accurate. This documented increase in proximal colon cancers and redistribution of lesions within various large bowel segments indicate the growing importance of barium enema and colonoscopy as the optimal techniques for detection of colorectal neoplasms.

Colonic Neoplasms↗
PubMedDate not supplied

Stereotaxic fine needle aspiration cytology of clinically occult malignant and premalignant breast lesions.

Stereotaxic fine needle aspiration (FNA) cytology was used to study clinically occult (nonpalpable) breast lesions in 114 consecutive patients with mammographically suspicious findings prior to excisional biopsy. The aspirate contained insufficient material for cytologic evaluation in 15 cases (13.2%), which were histologically diagnosed as benign (7 cases), atypical hyperplasia (7 cases) or carcinoma in situ (1 case). The cytologic findings indicated a benign lesion in 77 cases (67.5%), which were histologically diagnosed as benign (71 cases) or atypical ductal hyperplasia (6 cases). The cytologic sample showed atypia in eight cases (7.0%), which were histologically diagnosed as severe atypical ductal hyperplasia (three cases), carcinoma in situ (one case) or proliferative fibrocystic disease (four cases). In the eight cases (7.0%) cytologically interpreted as probably malignant, histology confirmed six invasive carcinomas, one carcinoma in situ and one fibrocystic disease. Of six cases (4.4%) cytologically reported as malignant, five were histologically diagnosed as invasive carcinoma and one as carcinoma in situ. Overall, stereotaxic FNA cytology reported as malignant or probably malignant 14 of the 15 cases with a histologic confirmation of malignancy, for a sensitivity of 93.3%. Cytology correctly identified 78 of the 83 histologically negative cases, for a specificity of 94.0%. The 16 cases histologically diagnosed as ductal hyperplasia, which carries a high risk for subsequent malignancy, were studied in detail in an effort to define histologic and cytologic criteria for this entity. Using selected histologic criteria, 11 of these cases were graded as showing mild-to-moderate atypical hyperplasia and 5 as showing severe atypical hyperplasia. Three of the latter cases were similarly identified by an analogous cytologic grading; the other two cases had insufficient cytologic samples. The total results in this series of 114 cases support the use of stereotaxic FNA cytology in the diagnosis of these nonpalpable breast lesions, examples of which are illustrated. In particular, it may help to raise the low specificity yielded by mammography alone, which would represent a significant advance for the patient in terms of the accuracy, expediency and reduced cost of diagnosing these lesions.

Adult↗