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Biomedical subjects

K Dowlatshahi

Publications and source records attributed to K Dowlatshahi.

At least 19 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 After the probe was inserted into the tumor, it was withdrawn as laser energy was administered at a rate sufficient to maintain the temperature within 42-45 degrees C. Tumors were excised after 48 hours, fixed in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↗
PubMed1985

Influence of morphine on the distal oesophagus and the lower oesophageal sphincter--a manometric study.

Basal pressure and relaxation of the lower oesophageal sphincter (LOS) as well as amplitude, duration and propagation velocity of peristaltic waves in the distal third of oesophagus were measured in 15 healthy adults (nine men and six women). A highly standardised technique was used employing manometric equipment including a low-compliance pneumohydraulic infusion system and a triple lumen recording catheter. After establishment of baseline manometry values the catheter was positioned with its distal orifice in the lower oesophageal sphincter. In 10 subjects 0.2 mg/kg body weight of morphine sulphate was then injected subcutaneously. In five others equal volume of saline was given. The manometric data were analysed blindly. Repeated manometric evaluations were carried out 15, 30, 45, 60, and 75 minutes after the injection. Morphine increased slightly LOS-pressure and significantly (p less than 0.001) decreased LOS-relaxation, the maximal effect occurring 30 minutes after the injection. Amplitude of peristaltic waves increased slightly but insignificantly, whereas propagation velocity and duration were uninfluenced. The results of this study suggest that pharmacologic doses of morphine influence normal function of the LOS and possibly the distal oesophagus. The role of endogenous opiates in this respect, however, awaits further studies. It is suggested that abnormalities in opioid neurotransmission may explain some of the non-specific oesophageal motility disorders.

Adult↗
PubMed1985

Brush cytology for the early detection of esophageal carcinoma among patients with upper aerodigestive malignancies.

The incidence of associated esophageal carcinoma (EC) among patients with upper aerodigestive tract malignancies is high. Esophageal brush cytology, as developed and evaluated as a screening device for early detection of EC among villagers of northeastern Iran, was employed to examine 56 clinic patients with known tumors of the upper aerodigestive tract on 106 occasions. Two asymptomatic EC were detected and are presented. The procedure was also used as an adjunct to endoscopy in order to monitor the response of tumors under treatment. Sensitivity of 40% and specificity of 90% were found and could be improved with more judicious application of the procedure. The use of this simple test for early detection of EC among this high risk subset of clinic patients is recommended.

Aged↗
PubMed1985

Management of locally advanced and inflammatory carcinoma of the breast.

From the data presented, there seems little doubt that multimodality systemic and local therapy offers the best chance of long term control and survival in patients with locally advanced noninflammatory and inflammatory carcinoma of the breast. However, the best method of sequencing these modalities remains inadequately defined. The rationale for systemic therapy is that systemic micrometastases are present at diagnosis; since almost all patients die from systemic disease, it would seem preferable to use chemotherapy first, while the disseminated tumor burden is low. Furthermore, this would allow an assessment of local response to the agents administered. However, chemotherapy almost never sterilizes bulky local disease, and local control rates are significantly improved by concurrent or sequential use of a local modality. From the information presented, it would appear that combined operation and radiotherapy may give a better outcome than either modality alone. However, in series in which chemotherapy plus one local modality are used, the five year, local failure rates were 20 to 35 per cent; with the use of two local modalities, the local failure rate was not significantly better (16, 20 and 22 per cent). The full effect of using two local modalities with systemic chemotherapy has not been satisfactorily explored to date. Many groups have suggested that the local control rate is proportional to the dose of radiotherapy given. Since iridium192 implantation permits larger doses of radiotherapy to the local tumor without an apparent increase in toxicity, it holds great promise as a means of improving local control in this disease and should be considered in all instances. Randomized studies comparing iridium192 with operation as an adjunct to external beam radiotherapy are needed. Although there is little doubt that combination systemic chemotherapy is mandatory for improved survival in these patients, the appropriate drugs, combination and scheduling are yet to be defined. Data from studies of metastatic carcinoma of the breast indicate that combinations of two to four drugs, including doxorubicin, give the best response rates. Recently, a number of anthracycline analogues have been studied, in particular mitoxantrone, with response rates comparable to doxorubicin but with less toxicity. These agents could be used effectively in future chemotherapy programs for locally advanced and inflammatory carcinoma of the breast. The place of endocrine manipulation also remains undefined. In general, women who present with carcinoma of the breast later in life are more likely to have hormone receptor positive, endocrine responsive tumors.(ABSTRACT TRUNCATED AT 400 WORDS)

Antineoplastic Agents↗
PubMed1985

Evaluation of brush cytology as an independent technique for detection of esophageal carcinoma.

In this study the accuracy of indirect brush cytology for detection of esophageal carcinoma is evaluated against current standard methods of diagnosis and is compared with the known accuracy rate of endoscopically directed brush cytology. A standard endoscopic nylon brush placed inside a nasogastric tube was used in 203 patients with various esophageal problems. Correct diagnosis was made in 78% of cancers, 95% of potentially premalignant cases, and 100% of cases of normal esophageal mucosa with both indirect and directed brushing procedures. The technique meets most requirements of a new screening procedure as being simple, safe (no complications), relatively inexpensive, and acceptable to patients (98% compliance). Currently it is employed to monitor high-risk esophageal conditions and post-treatment courses of patients with pharyngoesophageal tumors for local recurrence or a new primary lesion in the esophagus.

Adenocarcinoma↗
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↗