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Biomedical subjects

T J Wieman

Publications and source records attributed to T J Wieman.

72 records · Page 4Linked to original sources
PubMed1988

Evaluation of endoscopy training in a general surgery residency.

To evaluate the gastrointestinal endoscopy training program, a survey of the 33 former chief residents, who finished our program in 1981-1986, was conducted. All 33 graduates responded; 22 graduates are general surgeons, 11 completed or are completing training in a surgical specialty. Eighteen of the 22 general surgeons routinely perform endoscopy in their practice. Graduates in cities with a population greater than 250,000 are as likely to perform endoscopy as the surgeons who live in smaller communities. Ninety one per cent consider endoscopy training to have been an important part of their surgical training. Based on this assessment, endoscopy training is an important part of a general-surgery residency.

Colonoscopy↗
PubMed1986

Lasers and the surgeon.

The evolution of laser technology in medicine has progressed rapidly over the past 25 years, and these devices are widely used in surgical treatment today. Three different types of lasers are predominantly used: the carbon dioxide, argon ion, and neodymium-YAG instruments. Each operates on similar principles but because of the different wavelengths of light emitted, their applications differ. However, by and large, all of them utilize thermal energy generated by light and tissue interactions. Recently, the combination of an argon ion and a dye laser used with photosensitizing drugs has shown promise in the treatment of cancers, and this represents a nonthermal application of laser technology. In order to use lasers effectively, a knowledge of the specific laser and tissue properties is essential. In the future, lasers will be used not only as thermal scalpels but also as instruments than can provide a very precise delivery of energy to parts of the body that are otherwise inaccessible without operation. The use of photodynamic therapy will provide a mechanism of selectively destroying tumors while leaving normal tissues intact.

Animals↗
PubMed1986

Photodynamic therapy with porphyrin and phthalocyanine sensitisation: quantitative studies in normal rat liver.

Selective sensitisation of malignant tumours to monochromatic light (photodynamic therapy, PDT) is a promising approach to cancer treatment, but current sensitisers are unsatisfactory and the parameters controlling effects produced in normal and neoplastic tissue are poorly understood. To quantify the effects in a relatively homogeneous organ, we carried out experiments in the livers of normal rats following systemic sensitisation with haematoporphyrin derivative (HpD) and a new sensitiser, a sulphonated aluminium phthalocyanine (AlSPc) using light from an Argon pumped tunable dye laser. Damage from PDT (dominant at 100 mW laser power) could be distinguished from that due to local hyperthermia (dominant at 400 mW). For both sensitisers, the extent of PDT necrosis increased with the applied light energy and was abolished by occluding the hepatic blood flow during therapy. With HpD, the extent of PDT necrosis was maximum with only a few hours between sensitisation and therapy, and was not detectable when this interval was increased to a week. With AlSPc, the extent of necrosis in liver changed little with sensitisation times from 1 h to 1000 h (6 weeks), and declined slowly thereafter, matching the amount of AlSPc measurable by alkali extraction, although prolonged photosensitisation was not seen with AlSPc in muscle. Less cutaneous photosensitivity was seen with AlSPc than with HpD. AlSPc is easier to produce and handle than HpD, has a more appropriate strong absorption peak (at 675 nm) and from these results, warrants further study as a photosensitiser for PDT.

Animals↗
PubMed1984

Management of malignant ascites.

The management of malignant ascites is a significant clinical problem. Although most of the patients who have this complication develop have rather significantly limited life expectancy rates, they may be successfully palliated if appropriate steps are taken to provide them with the proper therapy. All of the aforementioned treatment modalities, specifically intracavitary radiotherapy, radioactive colloids, intracavitary chemotherapy, peritoneovenous shunting and immunotherapy have distinct advantages and limitations. With the proper selection of the modality to fit the individual patient, a relatively good result can be obtained, providing, of course, that proper care is taken to anticipate the potential complications, which occur frequently in the treatment of malignant effusion.

Animals↗
PubMed1983

Responsiveness of metastatic basal-cell carcinoma to chemotherapy. A case report.

Basal cell carcinoma normally causes major morbidity only by direct extension of the tumor into adjacent tissues. Occasionally the tumor will metastasize to distant sites such as the lungs, the bones, regional lymph nodes, and the abdominal viscera. Over 100 cases of this disseminated disease are reported in the literature. Once a tumor has metastasized beyond the regional lymph nodes it is uniformly fatal. This article reports a case of basal cell carcinoma, metastatic to the lung, which was successfully treated with cisplatin. Three other cases treated similarly are reviewed, and the prospects for treatment of advanced basal cell carcinomas with chemotherapy are discussed.

Basal Cell Carcinoma↗
PubMed1980

Diversion of duodenal contents: its effect on the production of experimental gastric cancer.

Diversion of duodenal contents after gastroenterostomy and vagotomy did not protect 240 laboratory rats from increased risk of gastric carcinoma. They were divided into three groups of 80: group 1 received 0.9 mg of 3-methylcholanthrene injected submucosally into the gastric antrum; groups 2 and 3 had bilateral truncal vagotomy and gastroenterostomy, with carcinogen injected into the gastric submucosa near the anastomosis; group 3 also had total duodenoenteric diversion. Blind histopathologic examination of surviving rats during necropsy eight months later disclosed that cancer had developed in six of 60 (10%) group 1 rats, in 23 of 71 (33%) group 2 rats, and in seven of 27 (22%) group 3 rats. Compared with group 1, groups 2 and 3 had an increased incidence of gastric cancer but did not differ from one another in this regard.

Adenocarcinoma↗
PubMedDate not supplied

The use of ERCP in the management of common bile duct stones in patients undergoing laparoscopic cholecystectomy.

The purpose of this study was to evaluate the indications and results of endoscopic retrograde cholangiopancreatography (ERCP) for gallstone disease since the advent of laparoscopic cholecystectomy. In our personal series of 410 consecutive cases of laparoscopic cholecystectomy, we found 17 common bile duct (CBD) stones; seven were identified by preop ERCP, nine at laparoscopy by intraoperative cholangiography, and one postop by ERCP. We have performed preop ERCP in 21 patients (5.1%); CBD stones were found in seven. Our indications for preop ERCP were elevated liver function tests, dilatation of the common duct by ultrasound, or a history of jaundice/pancreatitis, and all stones were successfully removed by endoscopic sphincterotomy. At laparoscopic cholecystectomy nine patients were found to have stones; one was treated with laparoscopic methods, four with open CBD exploration, and four by postop endoscopic sphinecterotomy. Post-laparoscopic cholecystectomy, five patients underwent ERCP for pain or increased liver function tests suggestive of common duct stones. One of the five was found to have stones and these were successfully removed by endoscopic sphincterotomy. ERCP is very useful as a diagnostic and therapeutic modality in laparoscopic cholecystectomy patients with suspected CBD stones. Elevated liver function tests and dilated CBD by ultrasound are the most accurate predictors of stones. Endoscopic sphincterotomy is a more effective route, at present, for stone removal than a laparoscopic approach.

Adolescent↗
PubMedDate not supplied

Efficacy and safety of becaplermin (recombinant human platelet-derived growth factor-BB) in patients with nonhealing, lower extremity diabetic ulcers: a combined analysis of four randomized studies.

The results of a combined analysis and separate analyses of four multicenter, randomized, parallel group studies that evaluated the effects of once-daily topical administration of becaplermin gel for the treatment of chronic, full thickness, lower extremity diabetic ulcers are presented. The four studies included a total of 922 patients with nonhealing lower extremity diabetic ulcers of at least 8 weeks' duration. Following initial complete sharp debridement of the ulcer, patients were randomized to receive a standardized regimen of good ulcer care alone, good ulcer care plus placebo gel, or good ulcer care plus becaplermin gel-30 microg/g, or good ulcer care plus becaplermin gel-100 microg/g, with various combinations of regimens used in the four studies. Safety was assessed by monitoring adverse events and by clinical laboratory evaluations. Meta-analytic statistical techniques were used in the combined analysis to establish homogeneity of treatment comparisons across studies. Based on an analysis of patients with baseline ulcer area common to all trials (</= 10 cm2), representing 95% of all patients, becaplermin gel-100 microg/g significantly increased (p = 0.007) the probability of complete healing compared with placebo gel. It was determined that for the median ulcer area of these patients, which was 1.5 cm2, the becaplermin gel-100 microg/g treatment group showed a 39% increase in complete healing compared with that of the placebo gel treatment group (50% vs. 36%, respectively, p = 0.007). Becaplermin gel-100 microg/g significantly decreased (p = 0.01) the time to complete healing compared with placebo gel, with the 35th percentile of time to complete healing being reduced by 30% (14.1 weeks vs. 20. 1 weeks, respectively). In patients with ulcers </= 5 cm2 at baseline (a more homogeneous group), becaplermin gel-100 microg/g also significantly increased the incidence of complete healing with a similar decrease in the time to healing. Adverse events reported during treatment or during a 3-month follow-up period were not unexpected for this patient population and were similar in nature and incidence across all treatment groups. We therefore conclude that treatment with becaplermin gel at a dose of 100 microg/g once daily, in conjunction with good ulcer care, is effective and well tolerated in patients with full thickness lower extremity diabetic ulcers.

Administration, Topical↗
PubMedDate not supplied

Vascular damage after photodynamic therapy of solid tumors: a view and comparison of effect in pre-clinical and clinical models at the University of Louisville.

Microvascular damage that results in blood flow stasis is a frequent consequence of photodynamic therapy. The magnitude of this response is dependent on the type of photosensitizer employed for treatment, the amount of drug and light used in therapy and the time period between drug injection and treatment. This review highlights the mechanisms that lead to blood flow stasis in tumor and normal tissues and discusses methods to increase the selectivity of vascular response.

Animals↗