The performance of students selected through a special program at St. Louis University School of Medicine.

PURPOSE: To compare the performances of students selected through a special program, the Medical Anatomy Preparatory Program (MAPP), at St. Louis University School of Medicine with those of students admitted at the traditional way. METHOD: The students were members of the classes of 1993-1996 at the St. Louis University School of Medicine (N = 654). Of these, 52 (8%) were MAPP students. The MAPP students and the non-MAPP students were compared on the basis of various test scores and grades obtained from the admission office, the registrar's office, and the office of curricular affairs. Means and standard deviations were computed for each group, and the MAPP students and the non-MAPP students were compared using analysis of variance to assess the statistical significance of any differences. RESULTS: The non-MAPP students were significantly better than were the MAPP students in terms of Medical College Admission Test scores, undergraduate gradepoint averages, grades for three major second-year courses, and performances on Steps 1 and 2 of the U.S. Medical Licensing Examination (all p < .001). There was no significant difference between the groups in grades for three major first-year courses or five major third-year courses. None of the MAPP students has been dropped for academic reasons. CONCLUSION: The MAPP program takes medical school applicants who have been rejected because of their preadmission performances, given them the opportunity to show that they can perform at the medical school level by taking the anatomy courses with the regular medical students, and accepts those who are successful. The results suggest that those chosen can satisfactorily complete the requirements for the MD degree.

Learning gross anatomy: dissection and prosection.

The gross anatomy course at St. Louis University School of Medicine consists of 40 regions or units covering the entire body and utilizes peer teaching in which students do every fourth dissection. One-fourth of the students learn each unit by dissecting; three-fourths learn from predissected material. Four multiple choice tests were studied to determine whether students scored better on questions on units they dissected than those who learned from predissected material. Results were adjusted on the basis of students' scores on whole tests. There were four teams of students and four tests resulting in 16 sets of questions. Dissectors scored better than nondissectors in 13 sets, but the overall differences were small (67.80 vs. 66.70). It is concluded that there is a small advantage gained from dissecting and demonstrating to their peers, but that learning from dissected cadavers is a satisfactory method of study, since our students traditionally score above the national average on the anatomy portion of the National Board Examination.

The degree to which accuracy of preoperative staging of laryngeal carcinoma has been enhanced by computed tomography.

In this retrospective study, the accuracy of preoperative staging by high-resolution CT and clinical evaluation (indirect-direct laryngoscopy) is compared to the postsurgical pathologic staging of laryngeal cancer. Forty-two patients who were admitted to St. Louis University Hospital between the years of 1978 to 1985 with diagnoses of laryngeal cancer were included. All patients received high-resolution CT scan of the larynx preoperatively and subsequently underwent total or partial laryngectomy. None of these patients received preoperative radiotherapy. The accuracy of the clinical vs. CT staging--as well as the accuracy of the staging by combination of the two modalities--was determined by comparison with the postsurgical pathologic staging. The accuracy was assessed separately for glottic, supraglottic, and transglottic carcinoma. The accuracy of CT staging for glottic carcinoma was 75%. However, clinical evaluation in this group of lesions was very reliable, offering 92.9% accuracy. The accuracy of CT staging increased in the supraglottic and transglottic lesions, to become superior to the clinical staging. With combined information gained by both examinations, the preoperative staging accuracy was 91.4% for supraglottic carcinoma and 87.5% for transglottic carcinoma. It is, therefore, recommended that high-resolution CT should be included in the preoperative staging of laryngeal cancer.

Muscle function studies in amputated lathyritic rats.

This study is presented to compare two methods of evaluating changes in muscle function after amputation of the left leg at the knee. Rats were fed a 50% Lathyrus odoratus diet, which causes exostoses to develop at sites of attachment of certain muscles. The rats were on the experiment for 3, 6, or 9 weeks. Muscles of rats killed at 6 weeks were weighed to determine whether atrophy or hypertrophy had occurred. Sizes of exostoses were evaluated subjectively at each time period. The left adductor longus and quadratus femoris muscles underwent considerable atrophy and their exostoses were smaller than on the right side. The left iliopsoas increased in weight and had the larger exostosis. However, the left pectineus increased in weight but had the smaller exostosis. It is concluded that changes in muscle weights and changes in sizes of exostoses both reflect changes in muscle function, but because the two methods respond by different mechanisms, the results do not always agree.

Smooth muscle in the hepatic artery, portal vein and hepatic vein within the liver of the raccoon and guinea pig.

The amount and arrangement of smooth muscle in the intrahepatic vessels suggests that the guinea pig would be a good animal model for studying mechanisms controlling intrahepatic portal vein blood flow, while the raccoon would be good for studying hepatic vein mechanisms of control.

Lathyrism: mini-review and a comment on the lack of effect of protease inhibitors on osteolathyrism.

Lathyrism has been reviewed in respect to four overlapping phases: finding an animal model for neurolathyrism, characterizing osteolathyrism in respect to its possible use as an animal model for human diseases, such as Marfan's syndrome, idiopathic juvenile scoliosis, etc., use of beta-aminopropionitrile (BAPN) as a tool to study collagen, and use of BAPN as a therapeutic agent in man. Because it has been suggested that the lathyrogen, BAPN, may stimulate the release of proteases, the protease inhibitors Trasylol and epsilon-aminocaproic acid (EACA) were given alone or in combination to BAPN-treated rats. The protease inhibitors did not reduce the effects of BAPN as measured by exostosis formation or collagen extractability.

Periosteal stimulation by artificial tension.

The role of tension in the formation of exostoses in lathyritic rats was studied by applying artificial tension to the tendon of insertion of the adductor longus muscle. Exostoses were formed in the periosteum at the insertion site in rats fed a 50% Lathyrus odoratus diet, given artificial tension and a normal diet, and given artificial tension and a lathyrus diet. The latter were the largest. It is concluded that tension plays an important role in the formation of lathyritic exostoses and that tension alone can cause exostosis formation in the rat.

Effect of phenytoin and/or beta-aminoproprionitrile on a surgically induced periosteal wound.

Phenytoin has a beneficial effect on wound healing and on the healing of bone fractures, while beta-aminopropionitrile (BAPN) has an adverse effect on both. BAPN causes what appears to be a repair response in the periosteum at sites of muscle attachment, but phenytoin does not alter that response. The effect of phenytoin and/or BAPN on the repair of a surgically induced periosteal wound at the insertion of the adductor longus and pectineus muscles was studied in rats at 7 days post-wounding. Phenytoin facilitated and BAPN exacerbated the repair process, as indicated by the size of the periosteal response. Phenytoin increased the percentage of bone present in the responses, and both phenytoin and BAPN reduced the amount of cartilage present. The possible role of inflammation in obtaining the beneficial effects of phenytoin in wound healing is discussed.

Improved diagnostic accuracy in laryngeal cancer using a new classification based on computed tomography.

The most commonly accepted classification of laryngeal cancer is based on the definition of regions formulated by the American Joint Committee on Laryngeal Cancer. The limitations of this classification are discussed. A new radiologic classification based on computed tomography (CT) is presented, its application illustrated, and its accuracy documented. This classification has the advantage that it provides information preoperatively which closely agrees with the pathologic facts seen postoperatively. It also helps to separate those tumors that tend to invade cartilage from those that do not.

Improved diagnostic accuracy in the TNM staging of laryngeal cancer using a new definition of regions based on computed tomography.

Neither laryngoscopy nor laryngography can match the accuracy with which computed tomography (CT) can display the full tumor extent or the presence of cartilage invasion. Data obtained from a CT-histologic correlative study have suggested a new definition of regions of the larynx for use with the TNM staging of laryngeal cancer. The arytenoid cartilage, readily identifiable by CT, is used for reference. The regions are as follows: (a) supra-arytenoid, (b) midarytenoid, (c) vocal process, and (d) infra-arytenoid. Tumors with a strong propensity for cartilage invasion can be distinguished from those without this tendency. In addition, tumors with different pathways of lymphatic drainage can be identified.

Computed tomography vs. histology of laryngeal cancer: their value in predicting laryngeal cartilage invasion.

Twenty-seven cancerous larynges were examined preoperatively by computed tomography and postoperatively by transaxial anatomic sections. Data from this correlative study provides a new radiographic classification based upon the relationship of the plane of maximal tumor size to the apex, body, or vocal process of the arytenoid. Unlike those tumors whose maximal size lies at or above the apex of the arytenoid, those below have a very high association with cartilage invasion (8% in former group, 86% in latter group). This is explained by our observation of sites of predilection of tumor invasion of the thyroid, cricoid, and arytenoid cartilages. At these sites collagen fibers have been observed to pass through the perichondrium and attach directly to cartilage. These same fibers may serve as a pathway to direct growth of tumor cells. There was no correlation between six histologic parameters and the presence of cartilage invasion.

Computed tomography of herniated and extruded nucleus pulposus.

Computed tomography (CT) is an accurate method of diagnosing herniated nucleus pulposus (HNP) in patients with back pain and radiculopathy. We evaluated 188 patients with 244 disk space explorations for the treatment of back pain and radiculopathy. In predicting HNP, CT was 92% accurate and myelography was 88% accurate. The only significant difference between the two modalities is at L5-S1. Here CT was 92% accurate in predicting HNP and myelography was 70% accurate, a difference that is statistically significant (p less than 0.01). The dural sac separation reduces the myelogram accuracy at L5-S1. In detailed evaluation of 188 patients with both CT-diagnosed and surgically confirmed HNPs, these HNPs were classified by location, calcification, size, and extrusion. If the maximum anteroposterior diameter of the HNP was less than one-half the anticipated normal sagittal diameter of the dural sac, the incidence of extrusion was less than 10%. If it occupied one-half or more of the anticipated normal sagittal diameter of the dural sac, the incidence of extrusion was greater than 90%. This difference is highly statistically significant (p less than 0.001). Thirty-five percent of the HNPs exhibited some degree of migration with the cephalic direction more common than the caudal direction. Computed tomography and myelography are both satisfactory methods of diagnosing HNP. The noninvasive CT gives direct anatomical information and is more accurate at L5-S1. If the physical examination correlates with the CT examination, then myelography may be bypassed and the patient treated with a high degree of confidence.

Anatomical routes for cancer invasion of laryngeal cartilages.

The larynx is separated into compartments bounded by connective tissue membranes and cartilages. The membranes and cartilages affect the localization and spread of cancer for a while, but invasion eventually occurs. Histological study of the cartilages in the earliest stages of invasion shows cancer cells growing between the collagen bundles where the connective tissue membranes attach to the cartilages. At these points, the collagen bundles pass obliquely through the perichondrium to anchor into the cartilage and bone like Sharpey's fibers. As the cancer cells multiply, they separate the collagen bundles, forming linear passageways through the perichondrum. This appears to be the mechanism for cartilage invasion. Thus the sites of attachment of the strongest membranes are also the most frequent sites of invasion, i.e., the anterior commissure tendon and the cricothyroid membrane.

Ossification of the laryngeal cartilages as it relates to computed tomography.

Ossification of adult laryngeal cartilages was studied using cross sections cut in planes parallel to those used in computed tomography (CT). The percentage of ossification of surfaces of thyroid laminae was calculated and marked variations were found. There was no correlation between ossification and age (all subjects were 50 years or older). Generally, laryngeal cartilages of men were ossified to a greater extent than those of women. Some male cartilages were only slightly ossified, however, while some female cartilages were nearly completely ossified. Inner and outer surfaces of thyroid laminae differed by as much as 35% in some cases. Left and right laminae showed even greater differences, indicating that symmetry of ossification is not the rule. Ossification of arytenoid and cricoid cartilages also varies. This study reveals that there is no reliable pattern of ossification of laryngeal cartilage that would be of use the radiologist in evaluating CT scans for invasion of cartilage by cancer.

Computed tomography vs laryngography: a comparison of relative diagnostic value.

The computed tomography (CT) scans and laryngograms of 25 patients with laryngeal cancer were compared and evaluated in an assessment of the diagnostic accuracy of each modality in the supraglottic, glottic, and subglottic regions. Fourth generation scanners were used in these patients, all of whom subsequently underwent laryngectomy or partial laryngectomy. The clinical superiority of CT scanning was evident in several areas--confirming clinical impressions that laryngography is not as accurate as CT, is frequently misleading, and offers no significant advantages over CT. In this regard, we now believe that computed tomography is the most important radiologic adjunct in the diagnosis of laryngeal cancer, and we no longer order the laryngogram on a routine basis.

Staging of carcinoma of the larynx: comparative accuracy of ct and laryngography.

The accuracy and clinical usefulness of both computed tomography (CT) and laryngography were evaluated in 30 patients with carcinoma of the larynx. The radiologic results were correlated with the surgical and pathologic findings. The accuracy in determining tumor compartmental localization (supraglottic, glottic, or subglottic) was as follows: CT provided the correct diagnosis in 26 cases. There were three false negative and one false positive diagnoses. Laryngography provided the correct diagnosis in 19 cases. There were six false negative and six false positive diagnoses. In virtually all cases, CT provided information equivalent to or more accurate than laryngography. CT is recommended as the radiologic procedure of choice when additional diagnostic information is required to supplement the findings of laryngoscopy in determining the feasibility of conservation surgery.