Impact of a standardized patient intervention to teach breast and abdominal examination skills to third-year medical students at two institutions.

BACKGROUND: This study examined whether a single intervention with standardized patients (SPs) as a supplement to traditional teaching during the surgery clerkship would enhance the breast and abdominal examination skills of third-year medical students. METHODS: During the academic year 1994-1995, 153 students from two institutions were assigned to control or experimental groups. At institution A, all students underwent pretests and posttests with SPs; at institution B, no pretest was conducted. All experimental students received group and one-to-one instruction with SPs during the intervention session. RESULTS: At posttest, the experimental group performed better than the control group on breast examination (P = 0.002), professionalism during this examination (P <0.001), abdominal examination (P <0.001), and professionalism during the latter examination (P = 0.050). The improvement from pretest to posttest at institution A was significantly greater in the experimental group than the control group for the breast examination (P = 0.036) and the abdominal examination (P <0.001). Analyses on a variety of specific tasks within each examination were also performed. CONCLUSION: A single intervention with SPs teaching breast and abdominal examinations resulted in significant enhancement of these clinical skills.

Detection and cloning of a common region of loss of heterozygosity at chromosome 1p in breast cancer.

The short arm of chromosome 1 is frequently affected by rearrangements in a variety of human malignancies. Genetic alterations, predominantly deletions, which are indicative of the presence of a putative tumor suppressor gene at chromosome 1p, are observed in breast cancer. In order to define the altered locus, eleven highly polymorphic microsatellite markers on chromosome 1p were used to detect loss of heterozygosity. We analyzed 52 cases of breast cancer and found 4 common deleted regions at chromosome 1p. Twenty-two of 52 (42%) informative patients showed at least 1 affected locus. The region most frequently exhibiting loss of heterozygosity was 1p31 (11/39; 28%); the other three common deleted regions were 1p36 (10/44; 23%), 1p35-36 (5/40; 13%), and 1p13 (8/39; 21%). These data suggest that one or more putative tumor suppressor genes may reside on chromosome 1p. We have cloned the entire region of interest at 1p31 in yeast artificial chromosomes. This yeast artificial chromosome contig can be used for fine mapping of the region and cloning of the candidate tumor suppressor gene.

Laparoscopic gray-scale and color Doppler US: preliminary animal and clinical studies.

PURPOSE: To evaluate a semiflexible ultrasound (US) transducer inserted through a laparoscopic port to image abdominal structures. MATERIALS AND METHODS: Laparoscopic US with a 9.6-mm-diameter, 5.0-7.5-MHz semiflexible transducer with gray-scale, color, and spectral Doppler capabilities was performed in three miniature swine and in 25 patients with a variety of abdominal abnormalities. RESULTS: This miniature US probe was used to locate normal structures such as blood vessels, allowing the surgeon to decide the best approach for dissection. Color and spectral Doppler US proved especially useful in differentiating vascular from nonvascular structures. The presence or absence of stones in the gallbladder and common bile duct was readily determined. It was possible to detect masses and to provide guidance for their aspiration or biopsy within abdominal organs. In 10 cases (40%), laparoscopic US helped the surgeon make the decision for clinical management and altered the surgical procedures. CONCLUSION: Laparoscopic US was useful in assisting laparoscopic evaluation of abnormalities in the abdomen.

Loss of heterozygosity at 11q22-q23 in breast cancer.

Studies of loss of heterozygosity (LOH) in breast tumor DNA suggest that several tumor suppressor genes participate in the pathogenesis of breast cancer. Although the short arm of chromosome 11 has been implicated in breast cancer development, no previous LOH studies have indicated the involvement of a suppressor gene on 11q in breast carcinoma. To this end, tumor samples and corresponding normal tissue were collected from 62 unselected patients with primary breast cancer, and the extracted DNA was analyzed by polymerase chain reaction using microsatellite markers on chromosome 11. We found that 39% of the tumors (22 of 57 informative cases) revealed allelic loss in the region 11q22-23, and this loss was independent of LOH found to occur on 11p15. Interestingly, more than 90% of the tumors showed concordant loss of alleles at both 11q and 17p. The marker D11S528, showing LOH in 39% of informative cases, had the highest frequency of LOH among the markers that were used. The data presented indicate that the common overlapping region of LOH is between the loci D11S35 and D11S29, suggesting that this area contains a tumor suppressor gene frequently lost in breast cancer.

Sonographically guided laparoscopy and mediastinoscopy using miniature catheter-based transducers.

Miniature ultrasound transducers (12.5 MHz) housed in 9 Fr catheters were passed through a laparoscope or mediastinoscope to image a variety of normal and abnormal structures within the peritoneal cavity and mediastinum in 20 patients. These transducers made it possible to visualize the gallbladder and bile ducts and evaluate for the presence of stones, to detect masses and provide guidance for their aspiration or biopsy, and to image the internal structures of the ovary and fallopian tube. In addition, these miniature transducers were used to locate such normal vital structures as blood vessels, thereby allowing the surgeon to decide on the best approach for dissection during mediastinoscopy. During conventional surgery, the surgeon or gynecologist can palpate an area of abnormality not directly visualized. However, during laparoscopy and mediastinoscopy direct palpation is not possible. Therefore, it is important to find another method to determine what structures lie beneath the visualized surface. These miniature ultrasound transducers appear to offer a means for making such determinations.