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Biomedical subjects

S R Evans

Publications and source records attributed to S R Evans.

At least 37 records · Page 2Linked to original sources
PubMed1998

Can a one-day workshop alter surgeons' teaching practices?

BACKGROUND: A 1-day workshop, consisting of five sections with small group discussions and opportunities for practical application of participants' knowledge, was developed to enhance the teaching skills of practicing surgeons. Immediate and long-term follow-up surveys were completed by the participants. METHODS: Post-workshop evaluations were obtained from all participants who took the workshop; follow-up surveys were mailed 4 to 6 months later. RESULTS: Workshop quality was rated as good (25%) or excellent (75%) by all participants. Follow-up survey results indicated that many participants had rarely/never utilized cited references, looked for additional resources on specific topics, or referred to the section syllabus/handout materials provided during the workshop. However, 100% of the participant respondents reported that they had changed the way they teach as a result of their workshop attendance. CONCLUSION: An abbreviated course on surgical education can result in long-term changes in the participants' perceptions of their teaching practices. Further study is required to determine if these perceived changes in teaching practices, which the participants have directly attributed to their workshop attendance, have resulted in measurable improvement in their effectiveness and efficiency as teachers.

Education, Medical, Continuing↗
PubMed1998

Longitudinal analysis of the relationship between serum insulin-like growth factor-I and radiographic knee osteoarthritis.

OBJECTIVE: To examine the relation between serum insulin-like growth factor I (IGF-I) levels and both incident and progressive radiographic knee osteoarthritis (OA) in the Framingham Osteoarthritis Study. DESIGN: Subjects had bilateral weight-bearing, anterior-posterior knee radiographs performed in 1983-1985 and again in 1992-1993. IGF-I levels were measured from blood specimens obtained in 1988-1989 by a competitive binding radio-immunoassay (RIA) after separation with octadecasilyl-silica cartridges of serum IGF-I from binding proteins. Participants without baseline radiographic OA [Kellgren and Lawrence grades (K&L) = 0-1] were classified as having incident disease if they had K&L > or = 2 grades at follow-up. Progressive OA was defined as an increase in K&L score of > or = 1 in knees with baseline OA (K&L > or = 2). All analyses were knee-based and sex-specific. We examined IGF-I tertiles in relation to the risk of incident and progressive radiographic OA separately, adjusting for age, body mass index (BMI), and baseline K&L score, and used generalized estimating equations to adjust for the correlation between fellow knees. RESULTS: Four hundred and forty-one participants had knee radiographs and serum IGF-I levels measured. No associations were found for serum IGF-I levels and incident [women: OR = 0.9 (0.6-1.7), men OR = 1.2 (0.6-2.6)] or progressive [women OR = 0.9 (0.6-1.6), men OR = 0.9 (0.3-3.0)] radiographic knee OA in either sex. Neither did we observe any association between IGF-I and worsening of individual radiographic features of OA (i.e., osteophyte growth and joint space loss). CONCLUSION: In summary, this longitudinal study did not demonstrate any association of serum IGF-I and incident or progressive radiographic knee OA. Further studies are needed to clarify the role of IGF-I in OA.

Case-Control Studies↗
PubMed1998

Intrathyroidal parathyroid cancer presenting as a left neck mass.

Parathyroid carcinoma is a rare clinical entity with a reported incidence of between 0.5% and 4% of all patients with primary hyperparathyroidism. Equally as unusual is the presence of an intrathyroidal parathyroid gland, which is usually found at the time of exploration by exclusion after extensive dissection has been performed in the usual anatomic locations for the parathyroid glands. This is the description of a case of intrathyroidal parathyroid cancer that presented as primary hyperparathyroidism with a left neck mass. On exploration, an enlarged left lobe of the thyroid was present and no left superior pole parathyroid gland was found with exploration. A left thyroid lobectomy was performed that confirmed a parathyroid cancer that was entirely intrathyroidal. This is the first known reported case in the literature of a carcinoma arising within the thyroid gland.

Carcinoma↗
PubMed1998

Vitamin D receptor expression as a predictive marker of biological behavior in human colorectal cancer.

To date, none of the potential biological markers in colorectal cancer attempts to link the epidemiological data with the molecular biology of the disease. In an attempt to link dietary and epidemiological factors and to obtain a better understanding of the molecular biology of colorectal cancer, we measured vitamin D receptor (VDR) expression in 75 human colorectal cancers as a potential predictive marker of the biological behavior of the disease. Our results showed that a high level of VDR expression was associated with a favorable prognosis. The results of the studies reinforce the potential role that VDR may play in the development of the pathogenesis of colorectal cancer. Larger studies looking exclusively at stage I and stage II disease will hopefully lead to the development of a sensitive hormonal marker that can be used to predict the biological behavior of colorectal cancer, identifying at-risk patients in need of adjuvant treatment.

Adult↗
PubMed1998

Growth inhibitory effects of 1,25-dihydroxyvitamin D3 and its synthetic analogue, 1alpha,25-dihydroxy-16-ene-23yne-26,27-hexafluoro-19-nor-cholecalcifero l (Ro 25-6760), on a human colon cancer xenograft.

The effect of 1,25-dihydroxyvitamin D3 and its synthetic analogue, 1alpha,25-dihydroxy-16-ene-23yne-26,27-hexafluoro-19-n or-cholecalciferol (Ro 25-6760), have been evaluated both in vitro and in vivo in human colorectal cancer cell lines expressing high (HT-29) and low (SW-620) levels of vitamin D receptor. 1,25-Dihydroxyvitamin D3 caused significant dose-dependent growth inhibition of HT-29 cells at concentrations ranging from 10(-11) to 10(-6). The antiproliferative effect of Ro 25-6760 on HT-29 cells was also dose-dependent with cell counts on day 6, ranging from 98% of control at 10(-11) M to 14% of control at 10(-6) M. However, 1,25-dihydroxyvitamin D3 and Ro 25-6760 did not have any growth inhibitory effect on SW-620 at all concentrations. In mice with HT-29 tumor xenografts, administration of vitamin D at 0.1 and 0.2 microg/injection i.p. three times/week did not cause any significant tumor growth delay, whereas synthetic analogue Ro 25-6760, at both concentrations, caused a significant tumor growth inhibition in comparison with the control arm. In 30% of mice treated by R0 25-6760 the tumors disappeared on average after the second injection, and tumor growth did not resume after drug withdrawal. However, both 1,25-dihydroxyvitamin D3 or Ro 25-6760 had no growth inhibitory effect at all applied concentrations in mice with the SW-620 tumor xenografts. The mechanism for this impressive growth inhibition is not yet elucidated and warrants further investigation.

Animals↗
PubMed1997

Carcinoma of the stomach following the Chernobyl nuclear accident.

Medical consequences of many nuclear accidents on humans are well studied, but the results pertaining to gastric cancer patients who were exposed to radiation as a result of the Chernobyl nuclear accident have not been analysed. In this study, the outcome of the surgical treatment of 68 gastric cancer patients who were exposed to radiation as a result of the Chernobyl nuclear accident was compared with that of 117 consecutive gastric cancer patients from uncontaminated areas of the Ukraine. Patients in the study group was significantly younger than that of the control group. Comparative analysis showed the same frequency of regional metastases (65.7% versus 71.1%, P > 0.05), but a smaller number of distant metastases (23.8% versus 38.1%, P < 0.05) in the study group. 41.2% of patients in the study group underwent total gastrectomy compared to 19.6% of patients in the control group (P = 0.002). Postoperative complications developed in 13.2% of patients in the study group, while postoperative mortality in the study group was 7.3% compared to 1.7% in the control group. A significant decrease in CD16 cells was noted in patients from the study group following the operative procedure. Young age, invasive tumours with smaller number of distant metastases, frequent necessity for total gastrectomy and combined operations with adjacent organs, a higher level of postoperative morbidity and mortality and low levels of natural killer cells (CD16+) with a tendency to decrease after surgery are characteristic of patients with carcinoma of the stomach affected by the Chernobyl accident.

Adolescent↗
PubMed1997

TNM staging of pancreatic carcinoma using helical CT.

OBJECTIVE: The purpose of this study was to determine the accuracy of helical CT scanning in predicting the stage of carcinoma of the exocrine pancreas using TNM staging guidelines and in predicting resectability of carcinoma of the exocrine pancreas. MATERIALS AND METHODS: Twenty-six patients with proven adenocarcinoma of the pancreas underwent uniphasic or biphasic helical CT scanning. Two observers unaware of the patient's surgical stage evaluated the CT examinations using the TNM system (with specific assessment and description of disease sites). In addition, the two observers rated confidence of nonresectability using a 5-point scale (ranging from 1, definitely resectable, to 5, definitely not resectable). Observer results and preoperative interpretations were compared with surgical findings. RESULTS: Nineteen of 26 patients had nonresectable disease. The combined observer scores showed correct determination of T stage in 77% of patients, of N stage in 58%, and of M stage in 79%. The overall accuracy in determining lack of resectability was 96% and 84% for the two observers. All errors in determining resectable versus nonresectable disease occurred when the observer was not maximally confident of his or her diagnosis. CONCLUSION: Helical CT is an effective screening technique for assessing T and M stages of pancreatic carcinoma. However, helical CT is poor at detecting regional lymph node involvement. In patients with equivocal T-stage findings (such as questionable venous involvement), other studies such as endoscopic sonography may be of value.

Adenocarcinoma↗
PubMed1996

Vitamin D receptor and growth inhibition by 1,25-dihydroxyvitamin D3 in human malignant melanoma cell lines.

The expression of vitamin D receptors (VDR) and growth inhibition induced by 1,25-dihydroxyvitamin D3 have been noted in certain human malignant melanoma cell lines. In this study, widely disparate levels of VDR mRNA expression were demonstrated in a panel of eight human malignant melanoma cell lines. Quantitation of receptor level by ligand binding assay showed a similar pattern. Proliferation and growth curve analysis was performed in two cell lines: RPMI 7951 (high VDR) and SK-MEL-28 (low VDR). Significant growth inhibition was noted in RPMI 7951 cells at 10(-9) M 1,25-dihydroxyvitamin D3. SK-MEL-28 cells, which express much lower levels of VDR, did not show any growth inhibition except at extremely high concentrations of 1,25-dihydroxyvitamin D3, namely 10(-5) M. These findings suggest a receptor-mediated mechanism of growth inhibition for 1,25-dihydroxyvitamin D3 and a role for this hormone in the growth of malignant melanoma cells.

Calcitriol↗
PubMed1996

The effect of 1, 25-dihydroxyvitamin D3 on the growth of soft-tissue sarcoma cells as mediated by the vitamin D receptor.

BACKGROUND: Soft-tissue sarcomas, malignant neoplasms originating from mesenchymal tissue, are rare but highly aggressive tumors. Present modes of therapy are associated with high rates of recurrence. 1, 25-Dihydroxyvitamin D3, the active metabolite of vitamin D, serves as a potent antiproliferative agent in human cancer cells. METHODS: In this study, six soft-tissue sarcoma cell lines were analyzed for vitamin D receptor (VDR) expression, which was then correlated with the degree of growth inhibition in response to 1, 25-dihydroxyvitamin D3. These cell lines included rhabdomyosarcoma (HS729, A204), fibrosarcoma (HS913t), synovial sarcoma (SW982), liposarcoma (SW872), and leiomyosarcoma (SKLMS-1). The level of VDR messenger RNA (mRNA) expression was determined using a ribonuclease protection assay, and functional receptor content was determined by using a ligand-binding assay. Growth studies, including [3H]thymidine uptake and growth curves, were performed on two of the six cell lines that expressed the highest and lowest receptor levels. RESULTS: Ribonuclease protection and ligand-binding assays demonstrated variable levels of VDR, with HS729 showing high expression and A204 showing no expression. In HS729, [3H]thymidine uptake was significantly decreased at 10(-7) M (33%) and 10(-6) M (40%) 1, 25-dihydroxyvitamin D3. Growth curve studies showed significant growth inhibition of 55% at 10(-6) M. A204 cells showed no growth inhibition upon treatment with 1, 25-dihydroxyvitamin D3. CONCLUSION: This study demonstrates the existence of VDR in soft-tissue sarcoma cells and suggests a correlation between the level of VDR in cells and the degree of growth inhibition caused by 1, 25-dihydroxyvitamin D3 which may potentially serve as an alternative form of therapy for soft-tissue sarcomas.

Calcitriol↗
PubMed1996

Primary non-Hodgkin's lymphoma of the stomach: three radical modalities of treatment in 75 patients.

BACKGROUND: Non-Hodgkin's lymphoma (NHL) remains a rare form of gastric malignancy, with a rising incidence. Approaches to treatment vary from surgery alone to conservative management. METHODS: To determine the optimal scheme of treatment, a randomized clinical trial was undertaken. Seventy-five patients were randomized into three groups: A-surgery alone (25), B-surgery followed by chemotherapy (29), and C-radiation therapy followed by surgery and chemotherapy (21). Forty-nine patients had stage IE and 26 had stage IIE disease. Chemotherapy (COP and COPP) consisted of 6 courses during a 1-year period, with the courses being 6 weeks apart. RESULTS: Subtotal gastrectomy was performed in 26 patients. Forty-nine patients underwent total gastrectomy. Postoperative complications occurred in 6 (8%) patients: 3 (12%) in group A, 2 (6.9%) in group B, and 1 (4.7%) in group C. Postoperative mortality occurred in 2 (8%) patients in group A (2.7% of all patients). An increase in hospital admissions number per year and decrease of mean age of patients with NHL of the stomach after the Chernobyl accident on April 26, 1986 was noted. CONCLUSIONS: Improved survival in gastric NHL was achieved by a combination of preoperative radiation with surgery and postoperative chemotherapy, presumptively through the management of local and systemic disease.

Adolescent↗
PubMed1996

Postoperative complications requiring relaparotomies after 700 gastretomies performed for gastric cancer.

BACKGROUND: Prevention of fatal postoperative complications and improved management of patients with complications are important means of increased survival in gastric cancer patients. PATIENTS AND METHODS: A study of 700 patients undergoing gastrectomy was performed to examine factors that contributed to a high rate of postoperative complications. RESULTS: Of 700 patients undergoing gastrectomy for adenocarcinoma, 40 (5.7%) underwent reexploration because of serious complications. The frequency of the relaparotomies varied from 2.1% and 4.4% after regular subtotal and total gastrectomies, respectively, to 20% and 30.4% after palliative and conventional total gastrectomies, respectively. The complications that required reexploration most frequently were anastomotic leakage and incompetence of sutures (11, 27.5%), intra-abdominal abscesses (8, 20%), and pancreatic necrosis (7, 17.5%). A combination of preventive measures allowed the attainment of low rates of esophagojejunal anastomotic leakage (0.8%). CONCLUSION: We believe that the decision to perform an urgent reexploration, based on clinical findings, should generally be made by a group of experienced surgeons (not only the primary surgeon). Timely relaparotomy prevented death in 37.5% of the patients with serious acute postoperative complications.

Adenocarcinoma↗
PubMed1996

Predicting in-hospital mortality during cardiopulmonary resuscitation.

On the average, 10-15% of patients who undergo cardiopulmonary resuscitation (CPR) following a cardiopulmonary arrest in the hospital environment will survive to be discharged. The purpose of this study was to determine objective factors influencing patient outcome after CPR to determine who should be resuscitated and when to end CPR efforts. The records of 266 patients who underwent in-hospital CPR over a 3-year period were retrospectively analyzed with regard to age, gender, co-morbid conditions, setting of arrest, duration of resuscitation, initial pH and PO2 during resuscitation, and outcome of resuscitative efforts. Twenty-four (9%) patients survived to be discharged from hospital. Eighty-seven (33%) patients arrested in the intensive care unit, 77 (29%) on the ward, 91 (34%) in the emergency room, six (2%) in the cardiac catheterization laboratory and five (2%) in the operating room. There was no significant difference in survival based on location of arrest. Factors associated with a poor prognosis included age greater than 60, co-morbid disease (i.e. pneumonia, sepsis, renal failure, heart disease, etc.), an initial PO2 < 50 mmHg and CPR efforts extending beyond 10 min. Based on this data, guidelines regarding initiation and termination of CPR should be instituted in light of poor outcome in patients over 60 years of age with co-morbid conditions, specifically after 10 min of CPR.

Age Factors↗
PubMed1996

Chest wall fibromatosis associated with silicone breast implants.

Aggressive fibromatosis is a well described locally destructive benign lesion, comprising 0.3% of all solid tumors. Although the chest wall is a common location, this tumour has rarely been associated with breast tissue or breast implants. Herein is only the fourth case described in conjunction with a breast implant and the only case linked to a ruptured silicone implant. This tumour was locally aggressive and required wide surgical resection, including removal of the chest wall, to gain control. Wide surgical resection is recommended with the application of adjuvant radiation therapy being more controversial.

Adult↗
PubMed1996

Video-laparoscopic reduction of an intrathoracic stomach.

A paraesophageal hiatal hernia is caused by a defect in the anterolateral aspect of the diaphragmatic esophageal hiatus. Most commonly, the stomach migrates into the hernia sac. Although most patients are asymptomatic, repair is advised at the time of the diagnosis because of the high morbidity and mortality associated with surgery for the complications of paraesophageal hiatal hernias. However, because of the morbidity associated with conventional surgical techniques, there has been great reluctance to subject an asymptomatic patient to surgical repair. We report a minimally invasive technique for the reduction of a paraesophageal hiatal hernia and repair of the diaphragmatic hiatal defect. Video laparoscopy, with its attendant low morbidity, may be the ideal technique for the repair of paraesophageal hiatal hernias.

Female↗
PubMed1995

The antiproliferative effect of vitamin D analogs on MCF-7 human breast cancer cells.

We analyzed the antiproliferative effect of 1,25-dihydroxyvitamin D3 and four vitamin D analogs on MCF-7, a human breast cancer cell line known to express the vitamin D receptor. Growth curve studies and [3H]thymidine incorporation assays were used to assess the antiproliferative effect of 1,25-dihydroxyvitamin D3 (vitamin D), Ro 23-7553, Ro 24-5531, Ro 25-5317, and Ro 24-5583. Growth of MCF-7 cells was significantly inhibited by 1,25-dihydroxyvitamin D3 and all four analogs at 10(-8) M (P < 0.05). MCF-7 cells treated with analog had significantly less [3H]thymidine incorporation than cells treated with 1,25-dihydroxyvitamin D3 (P < 0.05). The affinity of the analogs for the vitamin D receptor was similar to that of 1,25-dihydroxyvitamin D3. These results demonstrate that analogs of 1,25-dihydroxyvitamin D3 are potent antiproliferative agents on human breast cancer cells and that this activity is likely mediated through the vitamin D receptor.

Adenocarcinoma↗
PubMed1995

Modulation of vitamin D receptor and estrogen receptor by 1,25(OH)2-vitamin D3 in T-47D human breast cancer cells.

1,25(OH)2-Vitamin D3 inhibits breast cancer cell proliferation through interaction with the vitamin D receptor (VDR). Regulation of VDR is under the influence of several factors which include the functional ligand for this receptor (1,25(OH)2-vitamin D3) as well as heterologous steroid hormones. We evaluated the nature of homologous regulation in T-47D human breast cancer cells with a radiolabelled ligand binding assay and a ribonuclease protection assay for VDR. Significant VDR up-regulation, as measured by hormone binding assays, occurred with pre-incubations with 10(-9)M through 10(-6)M 1,25(OH)2-vitamin D3 (P < 0.05). A 7-fold VDR up-regulation with 10(-8)M 1,25(OH)2-vitamin D3 occurred at 4 h treatment and was not associated with an increase in VDR mRNA expression on ribonuclease protection assay. This supports the hypothesis that up-regulation of VDR is probably the result of ligand-induced stabilization of pre-existing receptor. All-trans-retinoic acid, the progesterone analog R-5020, and prednisone were found to induce heterologous up-regulation of the VDR. We then determined with ligand binding assays whether 1,25(OH)2-vitamin D3 could influence receptor levels for another hormone in a manner analogous to the heterologous regulation of VDR. Regulation of estrogen receptor (ER) by 1,25(OH)2-vitamin D3 was studied in T-47D and MDA-MB-231 breast cancer cells. Incubation of T-47D cells, which are ER (+), with 10(-8)M 1,25(OH)2-vitamin D3 did not result in up-regulation of ER. Yet estrogen binding was significantly up-regulated in a cell line that is ER(-), MDA-MB-231. The increased estrogen binding was associated with a shift in binding affinity and ribonuclease protection assay showed absence of ER mRNA in these cells, suggesting an up-regulation of estrogen binding proteins and not of the ER itself.

Breast Neoplasms↗