Biomedical subjects

K A Yeh

Publications and source records attributed to K A Yeh.

At least 19 recordsLinked to original sources

PubMed2000

Peer teaching and computer-assisted learning: An effective combination for surgical skill training?

BACKGROUND: The surgical literature suggests that collaborative learning using peers may be a valid way to teach surgical skills and there is a growing interest in the use of computer-assisted learning for this purpose. Combining this evolving technology with this type of teaching would theoretically offer a number of advantages including a reduction in the amount of faculty time devoted to this task. In this study, we evaluate the efficacy of a type of collaborative learning in a computer-assisted learning environment. MATERIALS AND METHODS: We designed a prospective, randomized study comparing novice learners who were allowed to work in pairs with those who worked independently in a specially equipped computer-assisted learning classroom. Both pretest and posttest assessments were performed by videotaping this skill. Three experts then evaluated the videotapes, in a blinded fashion. Three different outcomes were assessed. RESULTS: Seventy-seven subjects were enrolled in and completed the study. Comparison of the outcome measures demonstrated no between group difference in the average performance scores or posttest times. The proportion of subjects who correctly tied a square knot was significantly lower in the computer-assisted peer teaching group when compared with the computer-assisted learning alone group (P = 0.04). CONCLUSIONS: Collaborative learning in a computer-assisted learning environment is not an effective combination for teaching surgical skills to novices.

Computer-Assisted Instruction↗

PubMed2000

The impact of external feedback on computer-assisted learning for surgical technical skill training.

BACKGROUND: Computer-assisted learning (CAL) offers a number of potential advantages for surgical technical skills teaching. The purpose of this study was to evaluate the impact of individualized external feedback on surgical skill acquisition when a CAL package is used for instruction. METHODS: Freshman and sophomore students participated in a 1-hour CAL session designed to teach them how to tie a two-handed square knot. One group received individualized external feedback during the session and the other group did not. Subjects were videotaped performing the skill before and after the session. The tapes were independently analyzed, in blinded fashion, by three surgeons. Three measures were obtained: the total time for the task, whether or not the knot was square, and the general quality of the performance using a rating scale. RESULTS: Data from 105 subjects were available for final analysis. For both groups there were significant increases in the proportion of knots that were square when the posttest performance was compared with the pretest performance but there was no difference between groups on this measure. Comparison of the performance scores demonstrated that both groups had a significant improvement after the session but the performance scores were significantly better in the group that had received feedback. CONCLUSIONS: Novices in both groups using CAL showed improvement in two of the outcomes measured, suggesting that subjects in both groups attained some degree of competence with this skill. The higher posttest performance score for the group receiving feedback demonstrates that external feedback results in a higher level of mastery when CAL is used to teach surgical technical skills.

Analysis of Variance↗

PubMed2000

Surgery for T4 breast carcinoma: implications for local control.

Despite increasing public awareness and widespread availability of mammography, many patients will present with locally advanced breast cancers. The role of surgery remains controversial. Between 1993 and 1998, 47 of 393 (11.9%) breast cancer patients presented with T4 (inflammatory or locally advanced) carcinoma. We reviewed multimodality management, clinical response to neoadjuvant therapy, perioperative course and complications, and local control. Forty-six women and one man were diagnosed with clinical T4 breast cancer. There were 24 white and 23 African-American patients. Mean age at presentation was 54.5 (range, 31-88) years. Twenty-three patients had clinical metastases to axillary nodes, and five had distant metastases at the time of diagnosis. For these women, intent was for personal hygiene and control of pain. Neoadjuvant chemotherapy was given for 34 of 47 (72%) with 25 of 34 (73.5%) having partial or complete clinical response. There was no response or progression of disease in 9 of 34(26.5%). Forty-six patients underwent radical or modified radical mastectomy, whereas a single patient underwent breast conservation treatment. Twelve required tissue transfer for wound coverage. Although eight developed minor wound complications (cellulitis/flap separation), there were no major wound complications. Pathologically negative margins were achieved in all but one patient. To date, five women have developed local recurrence in either the chest wall (three) or axilla (two). Average time to local recurrence was 7.8 months. There is no evidence of local failure in the remaining 87 per cent. Locally advanced breast cancer is a common occurrence in certain populations. Multimodality management remains the standard of care. Surgical resection may allow for successful local control and, in certain situations, long-term cure.

Adult↗

PubMed1999

Protein kinase A regulatory subunits in colon cancer.

The protein kinase A (PKA) is classified as type I or II depending on the association of the catalytic subunit with either the R(I) or R(II) regulatory subunits. Alterations in the levels of these regulatory subunits and PKA activity itself appear to affect cellular proliferation and tumorigenesis. We examined colorectal tumor specimens from 45 patients to investigate the potential role of cAMP-related signaling molecules in regulating tumorigenesis. Western blot analysis (PKA subunit protein levels) and in vitro kemptide phosphorylation assays (PKA catalytic subunit activity) were performed on human colorectal tumor tissue homogenates. R(I)beta protein levels were decreased 200% in ascending and 50% in descending colonic tumors compared to adjacent mucosa. R(II) protein levels were decreased 77% in descending colonic tumors but no change was observed in ascending colonic tumors compared to adjacent mucosa. PKA activity and the absolute amount of catalytic subunit protein in ascending and descending tumors were unchanged compared to adjacent mucosa. Differences in cAMP-related signaling molecules exist between neoplastic and normal colorectal tissues. These differences may not only serve as potential therapeutic targets for chemotherapeutic agents, but also lead to the identification of novel regulatory mechanisms involved in cellular proliferation and tumorigenesis.

Adult↗

PubMed1999

Severe anal ulceration secondary to Histoplasma capsulatum in a patient with HIV disease.

Severe fungal infections have become increasingly common in the immunocompromised patient, including those infected with human immunodeficiency virus. Histoplasma capsulatum occurs in about five per cent of acquired immunodeficiency syndrome patients in the endemic areas of the Mississippi and Ohio River Valley. Immunocompromised patients who present with severe ulceration and suppuration of the anus require exam under anesthesia and thorough laboratory evaluation for opportunistic infections. Thus, surgeons play a critical role in diagnosis and initiation of treatment. A case of infiltrating H. capsulatum of the anus is presented, including the natural history, presentation, diagnosis, and treatment.

AIDS-Related Opportunistic Infections↗

PubMed1999

Predictive value of flow cytometry for metastatic potential in breast cancer.

Breast cancer is the leading malignancy in women in the United States. Tumor size and nodal metastases have been the most important predictors of patient outcome and determinants of treatment, but have also been used to predict metastatic potential. This study was undertaken to ascertain the predictive value of flow cytometry for lymph node or systemic metastases. From 1994 through 1997, surgical specimens from 106 women who underwent treatment for invasive breast cancer were reviewed. Epidemiological data, tumor stage, nodal metastases, and flow cytometric data were collected. Analysis of variance and Student's t test were used to determine whether the presence of nodal metastases or distant metastases correlated with high S phase values and aneuploidy. Of the 106 patients studied, the mean age was 57 years; tumor size consisted of 35 per cent T1, 48 per cent T2, 8 per cent T3, and 9 per cent T4. Node status was found in the following distribution: 56 per cent node negative, 38 per cent N1, and 6 per cent N2. Distant metastases were present in four patients. Elevated S phase (defined as >9.0%) was present in 72 per cent of the population. Fifty-six per cent of these tumors were aneuploid. Node-negative patients had an elevated S phase in 66 per cent of cases, whereas node-positive patients had an elevated S phase in 71 per cent of cases. Neither S phase (P = 0.91) nor DNA index (P = 0.99) proved to be statistically significant in determining axillary node status. Neither did S phase (P = 0.87) nor DNA index (P = 0.48) consistently predict the presence of distant metastases. There is no statistical correlation between axillary node status and flow cytometric data. Breast cancers with high S phase values and aneuploid features do not reliably have axillary nodal metastases, and this data cannot replace that information provided by axillary node dissection. Synchronous systemic metastatic disease is also not predicted by flow cytometry.

Axilla↗

PubMed1999

Acantholytic variant of squamous cell carcinoma of the breast: a case report.

Primary squamous cell carcinoma of the breast is a rare clinical entity. Two large review series found only five cases out of a total of 8351 breast malignancies. This case report presents a patient with metaplastic, pseudoangiosarcomatous carcinoma or acantholytic variant of a squamous cell carcinoma of the breast. This diagnosis was based on the histological finding of highly atypical, acantholytic squamous cells. Because the tumor stained positive for keratin and negative for factor VIII, the diagnosis of angiosarcoma was ruled out. Although only scattered case reports have been published on this histological variant, these tumors tend to follow an aggressive course.

Acantholysis↗

PubMed1999

Mature presacral teratoma in an adult male: a case report.

Presacral teratomas are rare tumors derived from more than one embryonic germ layer and are usually diagnosed in infancy. It has been estimated that the incidence of presacral teratoma in children ranges from 1 in 30,000 to 1 in 43,000 live births. However, the diagnosis of these tumors in adults is extremely rare. H. Head et al. reviewed the world literature in 1975 and found only 71 reported cases. Since that time, an additional 14 cases have been reported, and only one of these was found in the United States. This study reports a case of an adult male who presented with recurrent infected pilonidal cysts that proved to be benign presacral teratoma at biopsy. The patient underwent resection by left hemisacrectomy and primary closure using a posterior approach and, since this procedure, has had no evidence of recurrence. The case is presented along with a review of the relevant literature.

Adult↗

PubMed1998

Computer-assisted learning versus a lecture and feedback seminar for teaching a basic surgical technical skill.

BACKGROUND: Rapid improvements in computer technology allow us to consider the use of computer-assisted learning (CAL) for teaching technical skills in surgical training. The objective of this study was to compare in a prospective, randomized fashion, CAL with a lecture and feedback seminar (LFS) for the purpose of teaching a basic surgical skill. METHODS: Freshman medical students were randomly assigned to spend 1 hour in either a CAL or LFS session. Both sessions were designed to teach them to tie a two-handed square knot. Students in both groups were given knot tying boards and those in the CAL group were asked to interact with the CAL program. Students in the LFS group were given a slide presentation and were given individualized feedback as they practiced this skill. At the end of the session the students were videotaped tying two complete knots. The tapes were independently analyzed, in a blinded fashion, by three surgeons. The total time for the task was recorded, the knots were evaluated for squareness, and each subject was scored for the quality of performance. RESULTS: Data from 82 subjects were available for the final analysis. Comparison of the two groups demonstrated no significant difference between the proportion of subjects who were able to tie a square knot. There was no difference between the average time required to perform the task. The CAL group had significantly lower quality of performance (t = 5.37, P <0.0001). CONCLUSIONS: CAL and LFS were equally effective in conveying the cognitive information associated with this skill. However, the significantly lower performance score demonstrates that the students in the CAL group did not attain a proficiency in this skill equal to the students in the LFS group. Comments by the students suggest that the lack of feedback in this model of CAL was the significant difference between these two educational methods.

Computer-Assisted Instruction↗

PubMed1998

99m-Technetium sestamibi localized solitary parathyroid adenoma as an indication for limited unilateral surgical exploration.

BACKGROUND: Because of its successful localization of solitary adenomas, 99m-Technetium sestamibi (MIBI) may challenge the standard operation for primary hyperparathyroidism. METHODS: Thirty-five consecutive patients underwent preoperative MIBI localization to optimize a surgical approach. Single-site localization in 21 patients directed a limited unilateral neck exploration (UNE) with adenomectomy and ipsilateral gland biopsy. Fourteen patients who did not localize underwent bilateral neck exploration (BNE). Conversion to a bilateral operation was required in 1 UNE patient because no adenoma was found on that side. RESULTS: There were no significant differences in preoperative and postoperative serological markers between the two groups. However, the total operative time for UNE (49 +/- 21 minutes) was significantly less than for BNE (103 +/- 45 minutes; P <0.001). CONCLUSIONS: Preoperative MIBI scan-directed limited unilateral neck operation may be used reliably for primary hyperparathyroidism due to a single adenoma, and thereby reduce operative time, extent of surgical dissection, and risk.

Adenoma↗

PubMed1998

Aspergillus: a rare primary organism in soft-tissue infections.

Nonclostridial necrotizing soft-tissue infections are usually polymicrobial, with greater than 90 per cent involving beta-hemolytic streptococci or coagulase-positive staphylococci. The remaining 10 per cent are usually due to Gram-negative enteric pathogens. We describe the case of a 46-year-old woman with bilateral lower extremity fungal soft tissue infections. She underwent multiple surgical debridements of extensive gangrenous necrosis of the skin and subcutaneous fat associated with severe acute arteritis. Histopathological examination revealed Aspergillus niger as the sole initial pathogen. Despite aggressive surgical debridement, allografts, and intravenous amphotericin B, her condition clinically deteriorated and she ultimately died of overwhelming infection. Treatment for soft-tissue infections include surgical debridement and intravenous antibiotics. More specifically, Aspergillus can be treated with intravenous amphotericin B, 5-fluorocytosine, and rifampin. Despite these treatment modalities, necrotizing fascitis is associated with a 60 per cent mortality rate. Primary fungal pathogens should be included in the differential diagnosis of soft-tissue infections.

Aspergillosis↗

PubMed1998

Colorectal cancer in patients under forty: presentation and outcome.

Colorectal cancer is the third most frequent malignancy in adults of both sexes in this country, with 90 per cent of patients diagnosed after age 50 years. This disease is unusual in patients under 40 years of age, and controversy persists as to prognosis in this subset of patients. Patients diagnosed with invasive adenocarcinoma of the colon and rectum from 1985 to 1997 were identified. They were then grouped according to age (< 40 or > or = 40). Charts were reviewed with respect to patient epidemiologic characteristics, clinical presentation, tumor staging, and survival. Twelve women and 24 men less than 40 years of age (median, 31 years/range, 13-39 years) were diagnosed with colorectal adenocarcinomas. This represented 8.6 per cent of the total patients diagnosed with colorectal cancers during this time. Thirty-five (97%) had symptoms (pain, blood per rectum, weight loss, or alteration in bowel habits) before diagnosis, and 23 (64%) had multiple symptoms. Younger patients had more poorly differentiated tumors (28%) and more mucinous adenocarcinomas (26%) than the older group. Younger patients were more likely to present with stage III or IV disease (78%) as well. Despite these findings, the median survival for younger patients was no different than the older patients when compared by stage. Colorectal cancer in young adults is rare, but should be considered in the differential diagnosis for all patients with gastrointestinal symptomatology. The presentation of these patients is not unlike that of older patients. Those patients with early-stage disease should be treated aggressively, as long-term survival may be anticipated, whereas the outcome for those with metastatic disease is poor.

Adenocarcinoma↗

PubMed1998

Jejunal cirsoid aneurysm: a rare cause of massive lower gastrointestinal hemorrhage.

Diverticulosis and angiodysplasia are the most common causes of massive lower gastrointestinal hemorrhage. Lower gastrointestinal hemorrhage frequently resolves without determination of a definitive source. An uncommon cause of lower gastrointestinal tract hemorrhage is the small intestinal submucosal aneurysm. This poorly described entity, more commonly recognized as Dieulafoy's disease in the gastric mucosa, has been documented only rarely in the jejunum. We describe a case report of a 27-year-old man with a massive lower gastrointestinal hemorrhage. Diagnostic evaluation failed to identify the source on initial admission. The patient re-presented to the emergency room with recurrent bleeding, anemia, and hypotension. During a period of active bleeding, a number of diagnostic studies ultimately revealed the source to be the proximal jejunum. Inspection of the resected specimen identified a submucosal aneurysm on the mesenteric border. Histologic evaluation identified the pathologic entity as a cirsoid aneurysm.

Adult↗

PubMed1998

Immediate breast reconstruction in breast cancer: morbidity and outcome.

Breast reconstruction is frequently performed for and requested by women with breast cancer. There are continued concerns about the safety of this procedure. We reviewed the Medical College of Georgia experience with immediate breast reconstruction to determine overall morbidity and whether premorbid risk factors could predict complications. Patients were reviewed with attention to epidemiologic characteristics, comorbid medical conditions, and risk factors; hospital and operative course; immediate wound complications; and patient survival. t test and chi-square analysis were performed to determine risk factors for developing wound complications. Between October 1990 and December 1996, 55 patients underwent 62 mastectomies and immediate reconstruction for breast cancer or contralateral prophylaxis. There were 13 stage 0, 23 stage I, 16 stage II, 4 stage III, and 1 stage IV tumors. There were 19 prosthetic and 43 autologous tissue reconstructions. Eighteen patients had 24 wound complications. Major complications occurred in eight patients and required reoperation for implant removal (two bilateral), ventral herniorrhaphy, and split thickness skin grafting for tissue loss. Patients who were obese were statistically more likely to develop surgical wound complications. Tobacco use, age, comorbid medical illness, operative blood loss, length of operation, and length of hospital stay did not predict for the development of wound complications. Patients who underwent prosthetic reconstruction had a significantly higher rate of major wound complications when compared with those who had autologous reconstruction. There was a single case of delay of chemotherapy secondary to surgical wound complication. There were no cases of autologous flap loss or local recurrence. Median survival is 23 months (1-72 months). At last follow-up, 53 patients are alive and without evidence of local recurrence. Breast reconstruction may be performed safely for most breast cancer patients. Autologous tissue reconstruction is preferred and carries significantly less major morbidity. Reconstruction should not delay adjuvant chemotherapy.

Adult↗

PubMed1997

Cryosurgical ablation of hepatic metastases from colorectal carcinomas.

Surgical resection remains the only curative therapy for hepatic metastases from colon and rectal carcinoma. Many patients will be unresectable or have close microscopic margins. Cryoablation may improve local control and survival in those cases. From February 1992 to May 1995, patients with metastatic colon and rectal carcinoma who underwent cryoablation of surgical margins following hepatic resection or cryoablation of hepatic metastases were reviewed with attention to patient and tumor characteristics, clinical course, local control, and survival. Twenty-four patients (10 female, 14 male) with a mean age of 63 years (range, 34-84 years) underwent cryosurgical ablation for hepatic metastases. Twelve were for central lesions and 12 for gross or microscopically positive resection margins. Surgery was performed with curative intent for 21 and for palliation in 3 patients. The mean hospital stay was 8.4 days (range, 5-15 days). Complications included three cases of parenchymal cracking and a single bile leak. Two of 14 patients who developed pleural effusions required treatment. Perioperative mortality was 8.3 per cent (2 of 24): one myocardial infarction and one cerebrovascular accident. Four of 21 treated for cure had hepatic recurrence, and six had only extrahepatic recurrence. Median time to recurrence was 9.5 months. With median follow-up of 19 months, mean actuarial disease-free (DFS) and overall survival (OS) rates are as follows. Those with central lesions (n = 12) had a mean OS rate of 31 months and a mean DFS rate of 23 months. Those with close resection margins (n = 12) had a mean OS rate of 31 months and a median DFS rate of 19.5 months. Total patients (n = 24) had a mean OS rate of 32.7 months and a mean DFS rate of 23.5 months. We conclude that cryoablation of unresectable hepatic metastases or close resection margins is safe and may allow for improved survival in selected patients with metastatic colon and rectal carcinoma.

Actuarial Analysis↗

PubMed1997

Utility of fine-needle aspiration cytology and frozen-section examination in the operative management of thyroid nodules.

Fine-needle aspiration cytology has a high sensitivity for the diagnosis of solitary thyroid nodules. Certain diagnoses involving follicular histologies often cannot be made with needle biopsy alone. The utility of frozen-section examination of thyroid nodules, with particular regard to those lesions with follicular histologies, is also limited. We examined the correlation of fine-needle aspiration cytology and frozen-section examination in solitary thyroid nodules to determine the contribution of frozen-section examination to the operation. We reviewed the fine-needle aspiration cytology, frozen-section examination, and final pathology of 100 consecutive patients undergoing thyroidectomy for a solitary solid thyroid nodule in an 4-year period. The diagnoses were classified as indeterminant, benign, or malignant. The utility and impact of the diagnosis from fine-needle aspiration or frozen section on the operative procedure performed was analyzed. Fine-needle aspiration cytology as a diagnostic test for thyroid nodules demonstrated an indeterminant rate of 23 per cent, with a diagnostic accuracy of 77 and 92 per cent for benign and malignant disease, respectively. In all patients with inaccurate benign diagnosis on fine-needle aspiration cytology, follicular neoplasm was misinterpreted for follicular adenoma or multinodular goiter. In comparing frozen-section results, the indeterminant, benign, and malignant rates were 7, 96, and 64 per cent, respectively. Of the 23 patients with indeterminant results on fine-needle aspiration cytology, the intraoperative frozen-section diagnosis on 4 patients was deferred to permanent section; 18 received accurate cytological diagnosis; and in 1 patient, carcinoma was missed. Overall, the decision about the extent of surgical thyroid resection was changed in only 2 patients based on the frozen-section results. Preoperative evaluation with fine-needle aspiration cytology can accurately and appropriately define the extent of thyroid surgery in most patients with a diagnosis of malignant neoplasm or benign disease. Intraoperative frozen-section examination may be helpful if fine-needle aspiration cytology results are inderminant and in cases of follicular histology as an adjunct for evaluation of the thyroid nodule, but overall, frozen section does not contribute to the management of the thyroid lesion at the time of surgery.

Adolescent↗

PubMed1996

Abdominal wall reconstruction after temporary abdominal wall closure in trauma patients.

We retrospectively analyzed 36 patients requiring temporary abdominal wall closure on admission to a level I trauma center from 1988 to 1992. There were 10 deaths (28%) in the study population. Of the 26 survivors, 8 patients (31%) had primary fascial closure at initial hospitalization, whereas 18 patients (69%) required split-thickness skin grafting to visceral granulation tissue. Of these 18 patients, 13 have had ventral herniorrhaphy at subsequent admission. Eight of these patients had primary fascial closure, 4 required primary fascial approximation with prosthetic onlay reinforcement, and 1 required multiple operations including prosthetic reconstruction and eventual complex tissue transfer. Complications occurred in 3 patients (14%) and included two wound seromas, which were drained nonoperatively, and a wound infection necessitating removal of prosthetic material and subsequent reconstruction with complex tissue transfer. Follow-up reveals no recurrent hernia at 24 months. Abdominal wall reconstruction after temporary closure can be done safely and promptly, with good functional and esthetic results.

Abdominal Injuries↗

PubMed1995

Uptake by cells and photosensitizing effectiveness of novel pheophorbide derivatives in vitro.

Pheophorbide a prepared from the algae Spirulina was derivatized at the C(7)-carboxylic group by linking amino alkyls of various lengths and terminal functional groups. The compounds were purified by thin-layer chromatography (TLC) and by high-pressure liquid chromatography (HPLC). Solubilization of compounds by serum lipoproteins, the kinetics of compound uptake into mammalian cells, and photosensitizing effectiveness when activated by 673 nm laser light have been studied. Optimal photosensitizer uptake into cells and the greatest photosensitizing activity were observed with compounds having side-chain lengths of 4-6 carbon atoms which terminated in -OH and -CH3 groups. The most effective compounds were 3 orders of magnitude more potent than Photofrin in the degree of photoinactivation of cultured EMT-6 tumor cells. HDL and LDL significantly promoted the efflux of these photosensitizing drugs from cells, suggesting that their long-term retention in normal tissues in vivo would be minimal and produce little phototoxicity.

Animals↗