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Biomedical subjects

T J Wieman

Publications and source records attributed to T J Wieman.

At least 19 recordsLinked to original sources
PubMed2000

Bile duct carcinoma: trends in treatment in the nineties.

Surgical resection provides the only known chance of cure for cholangiocarcinoma, and even then the 5-year survival is only 10 to 20%, and only one-third of patients are resectable for cure at the time of diagnosis. In recent years we have had considerable experience with endoscopic stenting to palliate common bile duct cancers. This has prompted us to evaluate our results for both endoscopic and surgical treatment of cholangiocarcinoma. From January 1990 through June 1999, we reviewed our endoscopic retrograde cholangiopancreatography registry and the hospital records for patients we treated for cholangiocarcinoma. Fifty patients were identified: 45 with cholangiocarcinoma and five with gallbladder cancer (who were excluded). The surgical group consisted of 16 patients: in 14 patients, resection for cure was possible whereas two had palliative procedures. There was one mortality (6%) and the median survival was 16 months. There have been no long-term surgical survivors, but 2 patients are alive at 24 months. We treated 29 patients with advanced disease with endoscopic stents (the endoscopic group) mainly for relief of obstructive jaundice. Six of 29 patients in the endoscopic group were critically ill and died in less than 4 weeks, whereas 23 patients who were in better condition survived for a mean of 10 months (range 2-84 months). We conclude that for common duct bile cancer surgical resection remains the treatment of choice but is applicable in only 30 to 35 per cent of cases. Endoscopic stenting effectively relieves jaundice and can provide long-term palliation comparable with surgical bypass; 12 of 29 patients in our endoscopic group survived 12 months or longer, and one is alive at 84 months after initial stenting.

Adult↗
PubMed1999

Analysis of acute vascular damage after photodynamic therapy using benzoporphyrin derivative (BPD).

Benzoporphyrin derivative monoacid ring A (BPD-MA, verteporfin) is currently under investigation as a photosensitizer for photodynamic therapy (PDT). Since BPD exhibits rapid pharmacokinetics in plasma and tissues, we assessed damage to tumour and muscle microvasculature when light treatment for PDT was given at short times after injection of photosensitizer. Groups of rats with chondrosarcoma were given 2 mg kg(-1) of BPD intravenously 5 min to 180 min before light treatment of 150 J cm(-2) 690 nm. Vascular response was monitored using intravital microscopy and tumour cure was monitored by following regrowth over 42 days. For treatment at 5 or 30 min after BPD injection, blood flow stasis was limited to tumour microvasculature with lesser response in the surrounding normal microvasculature, indicating selective targeting for damage. No acute changes were observed in vessels when light was given 180 min after BPD injection. Tumour regression after light treatment occurred in all animals given PDT with BPD. Long-term tumour regression was greater in animals treated 5 min after BPD injection and least in animals given treatment 180 min after drug injection. The correlation between the timing for vascular damage and cure implies that blood flow stasis plays a significant role in PDT-induced tumour destruction.

Animals↗
PubMed1999

Analysis of pulmonary microvasculature changes after photodynamic therapy delivered to distant sites.

Photodynamic therapy (PDT) can exert local damage by direct tumor cytotoxicity, by disruption of the microvasculature or by a combination of these effects. Although systemic effects after PDT of small tissue areas (< 1% total body surface area) are unlikely, treatment of larger areas may result in an accumulated effect leading to toxicity. Several investigators have described animal death after high dose PDT to tumors on the hind limb of animals and hypothesized that a toxic shock syndrome caused by vasoactive agents released after PDT is responsible. Because one of the most vulnerable organs to toxic shock injury is the lung, we studied the systemic effects of local PDT to this organ by intravital microscopy using a pulmonary window chamber. The PDT treatment conditions (25 mg/kg Photofrin, 24 h, 150 J/cm2 630 nm, maximum area 6.28 cm2) were chosen that produce systemic toxicity and lethality in rats. Adhesion of leukocytes in the lung was monitored in vivo using anti-CD-13-labeled microspheres. The progression of pulmonary edema was assessed by monitoring the leakage of rhodamine-labeled albumin and by wet-to-dry lung weight ratios. Although an increased leukocyte adherence was observed and a significant number of animals died after the extensive PDT treatment, no biologically significant lung edema could be demonstrated. These data indicate that lung edema and acute respiratory distress syndrome is not the cause of death in these animals and that the toxicity is related to other mechanisms including circulatory shock after extensive muscle damage.

Animals↗
PubMed1999

The treatment of malignant endobronchial obstruction with laser ablation.

BACKGROUND: We compared a new endoscopic treatment for malignant endobronchial obstruction known as photodynamic therapy (PDT) with the more established therapy of neodymium: yttrium-aluminum garnet laser (Nd:YAG) therapy. METHODS: A retrospective review was conducted of the medical records at our institution from 1988 to 1999 of patients treated for bronchial obstruction by thermal laser vaporization (Nd:YAG) or by PDT using the tunable dye laser in combination with a light-sensitive dye (PDT). The Nd:YAG procedure vaporized the obstructing neoplasm, whereas the PDT procedure photoablated the obstruction. Thirty-day mortality and morbidity rates were analyzed for both treatment groups using chi-square analysis. RESULTS: Of the 102 patients who were suitable for review, 83 received treatment with the Nd:YAG laser and 19 patients received treatment with PDT. Morbidity rates were comparable in both groups (22% for Nd:YAG vs 31% for PDT; P > .05). Equally common complications in both groups were respiratory failure and hypoxemia. Five Nd:YAG patients (6%) died within 30 days after treatment (3 of respiratory failure, 2 of massive hemoptysis), whereas 2 patients (10%) in the PDT group (1 of massive hemoptysis, 1 of acute myocardial infarction) died (P > . 05). CONCLUSIONS: PDT and Nd:YAG have similar mortality and morbidity rates. In our experience, PDT is a better choice for the treatment of malignant bronchial obstruction because it is technically easier, potentially safer, and does not require general anesthesia.

Adenocarcinoma↗
PubMed1998

Photodynamic therapy for palliation of chest wall recurrence in patients with breast cancer.

BACKGROUND AND OBJECTIVES: Chest wall recurrence occurs in 5-20% of breast cancer patients. Until recently, the only treatments available were surgical resection or radiotherapy. Photodynamic therapy (PDT) is a new modality that uses a photosensitizer and light to destroy tumor cells selectively. We report here our experience with PDT as a treatment for chest wall recurrence. METHODS: Seven patients with breast cancer who had chest wall recurrence despite previous therapy were treated with PDT. Four patients received one treatment, one received two treatments at the same site, one received two separate treatments at different sites, and one received three separate treatments at distinct sites. Response and adverse events were monitored. RESULTS: The total response rate of 91% (10/11), with complete response (CR) in 73% (8/11) and partial response (PR) in 18% (2/11), was based on total number of treatments. The mean time to lesion healing was 73 days (range <30-99 days). One patient experienced a photosensitivity reaction after exposure to direct sunlight. No other adverse events were recorded. CONCLUSIONS: PDT is an effective treatment for chest wall recurrence in patients with breast cancer in whom other treatments have failed. PDT is also well tolerated, especially when compared with traditional therapies.

Adult↗
PubMed1998

Clinical efficacy of becaplermin (rhPDGF-BB) gel. Becaplermin Gel Studies Group.

The results of four multicenter, randomized, placebo-controlled, parallel group studies of the efficacy of becaplermin gel are reviewed here. The four studies included a total of 922 patients, all of whom received a standardized regimen of good ulcer care. Patients were randomized to receive placebo gel, 30 or 100 microg/g becaplermin gel, or good ulcer care alone. In Studies 1 and 2, the incidence of complete healing was significantly higher in patients receiving becaplermin gel (30 microg/g, Study 1; 100 microg/g, Study 2) compared with that in patients receiving placebo gel. In Study 3, which was not powered for statistical analysis, the incidence of complete healing in patients treated with 100 microg/g becaplermin gel was approximately twice that of patients treated with good ulcer care alone. In Study 4, there was no significant difference in the incidence of complete healing in patients treated with becaplermin gel versus good ulcer care alone.

Administration, Topical↗
PubMed1998

Resection of the metatarsal head for diabetic foot ulcers.

BACKGROUND: Diabetic foot ulceration is a worldwide health problem. Approximately 15% of the 10 million diabetic patients in the United States will develop a foot ulceration at some time in their lives. The presence of a foot ulcer in this population is extremely debilitating and dramatically increases the risk of lower extremity amputation, accounting for approximately 67,000 lost limbs each year. Additionally, the costs associated with treating foot ulcers in diabetic patients is a major expense in the overall care of this patient group. METHODS: An 11-year retrospective study was conducted to evaluate 101 consecutive patients with diabetic ulcers of the forefoot who were treated using resection of the metatarsal head as the primary means of obtaining wound closure. RESULTS: The results indicate that 88% of the ulcers were healed by using this technique, and relatively more rapidly than would be expected when compared with historical norms. CONCLUSIONS: Resection of the metatarsal head is a safe and relatively inexpensive procedure that facilitates closure of the lesion, helps to control infection, and prevents countless and costly amputations.

Adult↗
PubMed1998

Efficacy and safety of a topical gel formulation of recombinant human platelet-derived growth factor-BB (becaplermin) in patients with chronic neuropathic diabetic ulcers. A phase III randomized placebo-controlled double-blind study.

OBJECTIVE: To compare the efficacy and safety of topically applied recombinant human platelet-derived growth factor-BB (rhPDGF-BB) (becaplermin) with placebo gel in patients with chronic diabetic neuropathic ulcers of the lower extremities. RESEARCH DESIGN AND METHODS: This multicenter double-blind placebo-controlled phase III trial included 382 patients with type 1 or type 2 diabetes and chronic ulcers of at least 8 weeks' duration. After sharp debridement of the ulcer, patients were randomized to receive becaplermin gel 30 micrograms/g, becaplermin gel 100 micrograms/g, or placebo gel, in conjunction with a standardized regimen of good wound care until complete wound closure was achieved or for a maximum of 20 weeks. Moist saline-soaked gauze dressings were changed twice daily with study medication applied by patients or caregivers at the evening dressing change. Safety was assessed by monitoring adverse events (AEs) and by clinical laboratory evaluations. RESULTS: Compared with placebo gel, becaplermin gel 100 micrograms/g significantly increased the incidence of complete wound closure by 43% (50 vs. 35%, P = 0.007) and decreased the time to achieve complete wound closure by 32% (86 vs. 127 days; estimated 35th percentile, P = 0.013). AEs reported during treatment or during a 3-month follow-up period were similar in nature and incidence across all treatment groups. CONCLUSIONS: Becaplermin gel 100 micrograms/g, in conjunction with good wound care, significantly increased the incidence of complete wound closure and significantly reduced the time to complete closure of chronic diabetic neuropathic ulcers. The safety profile of becaplermin gel was similar to that of placebo gel.

Administration, Topical↗
PubMed1998

In vivo and in vitro photodynamic studies with benzochlorin iminium salts delivered by a lipid emulsion.

Benzochlorin iminium salts (BIs) are hydrophobic photosensitizers based on an octaethylbenzochlorin nucleus that absorb in the near-IR region of the visible spectrum. In these studies the photodynamic activities of the zinc, copper and metal-free BI derivatives were compared in vivo in C3H-HeJ mice bearing a mammary adenocarcinoma tumor line. In vitro studies were also performed with the radiation-induced fibrosarcoma tumor line. An argon-pumped Ti-sapphire laser tuned to deliver light between 710 and 800 nm or an Oriel arc-lamp filtered to deliver broadband light above 590 nm were used as light source. A lipid emulsion was used as the delivery system for sensitizers in all studies. A pronounced solvent dependence was observed for the Q band for each of all iminium salts examined. As an example, the metal-free (BI) derivative had an absorption maximum at 798 nm in dichloromethane and at 727 nm in serum. The action spectra showed a greater PDT response at blue-shifted wavelengths for each of the three iminium salts both in vivo and in vitro. Among the three derivatives, the zinc analog (ZnBI) produced the greatest tumor regression at the low drug/light dose of 0.7 (mumole/kg and 200 J/cm2. These results indicate that iminium salts have characteristics that may make them promising third-generation photosensitizers.

Adenocarcinoma↗
PubMed1998

Photodynamic therapy using mono-L-aspartyl chlorin e6 (Npe6) for the treatment of cutaneous disease: a Phase I clinical study.

The activity of a new photosensitizer, mono-L-aspartyl chlorin e6 (Npe6), was assessed in an ascending dose Phase I study for patients with superficial tumor. Eleven patients, with a total of 14 tumor sites, were treated with photodynamic therapy (PDT) using Npe6. Lesions included recurrent adenocarcinoma of the breast, basal cell carcinoma, and squamous cell carcinoma. The phototherapy protocol consisted of a single i.v. injection of 0.5-3.5 mg/kg Npe6, followed 4 h later by 25-100 j/cm2 at 664 nm of light. PDT using Npe6 caused no significant toxicity with the exception of temporary generalized skin photosensitivity. In all cases, light treatment caused immediate tissue blanching, followed by a marked necrosis of the tumor mass. Regression of tumor occurred over 24-48 h after the light treatment and was followed by the formation of a heavy eschar over the tumor site. Tumor regression was short-lived at Npe6 doses of 1.65 mg/kg and below. In two of three patients, tumor regression was either incomplete or tumors recurred within the 12-week observation period. Increasing the Npe6 dose to 2.5 or 3.5 mg/kg combined with 100 J/cm2 of light energy resulted in better control of tumor regrowth with 66% (6/9) of sites remaining tumor-free through 12 weeks observation. This increased tumor response came at the expense of the tissue selectivity observed at Npe6 doses of 1.65 mg/kg and below. There was no apparent selectivity for destruction of tumor compared with normal skin at Npe6 doses of 2.5 mg/kg and above. These data demonstrate that Npe6 is both an effective and safe photosensitizer for use in PDT and provide the impetus for continued study in Phase II clinical trials.

Aged↗
PubMed1997

Photodynamic therapy using a protoporphyrinogen oxidase inhibitor.

The use of endogenously created porphyrins as an alternative to photosensitizer injection for photodynamic therapy is a rapidly evolving area of study. One common method to induce porphyrin synthesis and accumulation in cells is the topical, oral, or parenteral administration of 5-aminolevulinic acid, a precursor for heme biosynthesis. Porphyrin accumulation may also be elicited by the use of enzyme inhibitors of the heme biosynthetic pathway. Groups of DBA/2 mice bearing SMT-F mammary tumors were placed on a diet containing 0-4000 ppm of a protoporphyrinogen oxidase inhibitor, FP-846. This agent blocks a critical step in porphyrin metabolism and results in elevated intracellular levels of protoporphyrin IX. Light treatment of tumors produced both initial and long-term regression that was dependent on the amount of inhibitor, the duration of inhibitor exposure to animals, and the amount of light used in PDT. Tumor regression occurred without significant destruction of normal tissues in the treatment field and without initial vascular constriction or blood flow stasis. Tumor cure in animals given 4000 ppm FP-846 in feed for 3 days and 300 J/cm2 602-670 nm light (23% cure) was similar to the response in animals given 10 mg/kg Photofrin and the same light dose (20%).

Animals↗
PubMed1997

Targeting of natural killer cells to mammary carcinoma via naturally occurring tumor cell-bound iC3b and beta-glucan-primed CR3 (CD11b/CD18).

Previous reports have suggested that malignant cells frequently generate a humoral immune response that is ineffective in tumor destruction. Despite coating tumors with IgM and IgG that activate the C system via the classical pathway, normal membrane regulators of C (e.g., membrane cofactor protein and CD59) prevent cytotoxicity. Moreover, C3 deposition on tumors does not result in cytotoxic recognition by phagocytes or NK cells bearing C3 receptors capable of mediating destruction of C3-opsonized bacteria or yeast. The current investigation showed that freshly excised mammary tumors bore IgM, IgG, and C3 detectable by flow cytometry. Normal sera contained natural IgM and IgG Abs reactive with breast tumor cell lines, and IgG Ab titers were increased in patients with breast cancer. Breast tumor cell lines incubated in normal serum from AB+ individuals activated the classical, but not the alternative, pathway of C and became coated with C3. Despite exhibiting membrane-bound C3, serum-opsonized breast tumor cell lines were not killed by CR3 (CD11b/CD18)-bearing NK cells. Priming of NK cell CR3 with small soluble yeast beta-glucan polysaccharides enabled CR3-dependent killing of these same C3-bearing tumor cell lines. Tests of mammary carcinoma cells from freshly excised tumors demonstrated that they also bore sufficient amounts of opsonic C3 for cytotoxic recognition by NK cells bearing polysaccharide-primed CR3, whereas they were largely resistant to NK cells bearing unprimed CR3. This study demonstrates the potential utility of using naturally occurring opsonic C3 on tumor cells for specific immunotherapeutic targeting by NK cells and phagocytes bearing polysaccharide-primed CR3.

Adult↗
PubMed1997

Constitutive and stimulated expression of ICAM-1 protein on pulmonary endothelial cells in vivo.

The expression of intercellular adhesion molecule-1 (ICAM-1) on pulmonary endothelial cells after stimulus and subsequent binding of neutrophils is a first step leading to lung injury. A similar process may dictate the binding of tumor cells to the pulmonary endothelium during metastasis. We report the development of a new technique that allowed us to monitor the location and relative expression of ICAM-1 levels on the luminal surface of the pulmonary microvasculature in vivo. This technique uses intravital microscopy together with a two-step labeling procedure involving fluorescent microspheres. Constitutive expression of ICAM-1 was not detectable to a significant level by our model, but expression was observed after upregulation by the systemic administration of TNF alpha. Sprague-Dawley rats were injected with 0-5.0 micrograms/kg TNF alpha and ICAM-1 expression was monitored through 24 hr. ICAM-1 expression was related to both the dose of TNF alpha administered and the time elapsed between injection of TNF alpha and observation. Injection of 5 micrograms/kg TNF alpha caused upregulation of ICAM-1 protein expression from 0.30 +/- 2.76 binding events/175,000 microns2 to 62.6 +/- 5.48 through 4 hr observation, after which levels returned to near baseline within 24 hr. The delay required for maximal expression is likely related to the time required for the cell to respond to the stimulus and generate ICAM-1 protein. Reductions in the relative numbers of ICAM-1 protein expressed between 4 and 24 hr in vivo are likely a result of protein turnover after the initial stimulus.

Animals↗
PubMed1997

The effects of thrombocytopenia on vessel stasis and macromolecular leakage after photodynamic therapy using photofrin.

Several studies have reported thrombus formation and/or the release of specific vasoactive eicosanoids, suggesting that platelet activation or damage after photodynamic therapy (PDT) may contribute to blood flow stasis. The role of circulating platelets on blood flow stasis and vascular leakage of macromolecules during and after PDT was assessed in an intravital animal model. Sprague-Dawley rats bearing chondrosarcoma on the right hind limb were injected intravenously (i.v.) with 25 mg/kg Photofrin 24 h before light treatment of 135 J/cm2 at 630 nm. Thrombocytopenia was induced in animals by administration of 3.75 mg/kg of rabbit anti-rat platelet antibody i.v. 30 min before the initiation of the light treatment. This regimen reduced circulating platelet levels from 300,000/mm3 to 20,000/mm3. Reductions in the luminal diameter of the microvasculature in normal muscle and tumor were observed in control animals given Photofrin and light. Venule leakage of macromolecules was noted shortly after the start of light treatment and continued throughout the period of observation. Animals made thrombocytopenic showed none of these changes after PDT in either normal tissues or tumor. The lack of vessel response correlated with the absence of thromboxane release in blood during PDT. These data suggest that platelets and eicosanoid release are necessary for vessel constriction and blood flow stasis after PDT using Photofrin.

Animals↗
PubMed1996

Endoscopic management of benign and malignant biliary strictures.

BACKGROUND: It is now possible to manage most extrahepatic bile duct strictures, benign or malignant, using endoscopic retrograde cholangiopancreatography (ERCP) with endoscopic dilatation and stenting. METHODS: Over a 5-year period we treated 218 patients with strictures of extrahepatic bile ducts. Eighty-six patients had benign biliary stricture. Endoscopic treatment was performed in 67 (78%) of these patients. Open surgical biliary drainage was preferred in 12 patients (14%), and 7 patients (8%) were managed conservatively without stenting or surgery. One hundred and thirty-two patients had malignant biliary stricture. One hundred and one patients (77%) underwent endoscopic stent placement. Thirty-one patients (23%) underwent surgery for potential curative resection after diagnostic ERCP. The average life span in the malignant stricture group was 5 months (range 0.1 to 25 months) after the initial endoscopic procedure. RESULTS: Altogether 313 endoscopic procedures in 218 patients were performed for benign and malignant bile duct strictures. Complications included hemorrhage in 8 (3%), pancreatitis in 10 (3%), and suspected retroperitoneal perforation in 2 (0.6%). There were no ERCP related deaths; one patient died of uncontrolled bleeding from transhepatic stenting. In benign strictures, there has been no recurrence of strictures after the last stent removal with a mean followup of 21 months (range 0.1 to 31 months). All complications were successfully treated conservatively. CONCLUSIONS: Endoscopic management of benign and malignant biliary stricture is possible with minimal morbidity and mortality and should be considered an acceptable option to surgical management.

Bile Duct Diseases↗
PubMed1996

Chemical modification of normal tissue damage induced by photodynamic therapy.

One of the limitations of successful use of photodynamic therapy (PDT) employing porphyrins is the acute and long-term cutaneous photosensitivity. This paper describes results of experiments designed to test the effects of two radiation protective agents (WR-2721, 500 mg kg-1 or WR-3689, 700 mg kg-1) on murine skin damage induced by PDT. C3H mice were shaved and depilated three days prior to injection with the photosensitiser, Photofrin (5 or 10 mg kg-1). Twenty-four hours later, the mice were injected intraperitoneally with a protector 30 min prior to Argon dye laser (630 nm) exposure. The skin response was followed for two weeks post irradiation using an arbitrary response scale. A light dose response as well as a drug dose response was obtained. The results indicate that both protectors reduced the skin response to PDT, however WR-2721 was demonstrated to be the most effective. The effect of the protectors on vascular stasis after PDT was determined using a fluorescein dye exclusion assay. In mice treated with Photofrin (5 mg kg-1), and 630 nm light (180 J cm-2) pretreatment with either WR-2721 or WR-3689 resulted in significant protection of the vascular effects of PDT. These studies document the ability of the phosphorothioate class of radiation protective agents to reduce the effects of light on photosensitized skin. They do so in a drug dose-dependent fashion with maximum protection at the highest drug doses.

Amifostine↗
PubMed1995

Treatment of hyperesthetic neuropathic pain in diabetics. Decompression of the tarsal tunnel.

OBJECTIVE: The authors evaluated the causal relationship between entrapment of the posterior tibial nerve and neuropathic pain and describe the results of nerve decompression in a selected group of patients with intractable pain. SUMMARY BACKGROUND DATA: Painful metabolic neuropathy has, until recently, been thought to be an irreversible and essentially untreatable complication of diabetes. Recent studies have shown that metabolic deterioration is only one component of the disease process. METHODS: A group of patients with intractable painful neuropathy and a positive percussion sign underwent posterior tibial nerve decompression. RESULTS: Nerve decompression relieved the pain in the majority of treated patients. Return of other sensory function also was noted. CONCLUSIONS: Painful diabetic neuropathy of the lower extremities is potentially reversible. It appears to be caused partially by nerve entrapment and can be reversed by decompression.

Adult↗