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Biomedical subjects

H B Ris

Publications and source records attributed to H B Ris.

At least 19 recordsLinked to original sources
PubMed1996

Intraoperative photodynamic therapy with m-tetrahydroxyphenylchlorin for chest malignancies.

BACKGROUND AND OBJECTIVE: Since there is no satisfactory treatment modality for diffuse malignant mesothelioma of the chest, we assessed surgical tumor resection followed by intraoperative photodynamic therapy with mTHPC in a phase I study. STUDY DESIGN/MATERIALS AND METHODS: Since 1990, eight patients have undergone intraoperative photodynamic therapy with m-tetrahydroxyphenylchlorin (mTHPC-PDT) following thoracotomy and surgical tumor resection. RESULTS: mTHPC-PDT-mediated tumor necrosis was characterized by tumor infarction due to tumor vessel necrosis and thrombosis, and its extent depended on drug-light conditions; 650 nm light delivered at 0.1 W/cm2 for 10 J/cm2 48 h after iv administration of 0.3 mg mTHPC/kg resulted in a 10-mm-deep complete tumor necrosis. Skin photosensitivity was related to the drug dose applied and occurred up to 17 days after iv administration of 0.3 mg mTHPC/kg, mTHPC-PDT of brachial plexus infiltrated by mesothelioma resulted in pain relief without deterioration of nerve function. CONCLUSION: Tumor resection and intraoperative mTHPC-PDT of the chest cavity is feasible under clinical conditions and offers local tumor control of sites involved. However, distant tumor spread was not prevented by this combined treatment modality and optimization of mTHPC-PDT is warranted for further intraoperative application.

Antineoplastic Agents↗
PubMed1996

Video-assisted mediastinal lymph node dissection assessed in an experimental setting.

BACKGROUND: Feasibility, completeness, and morbidity of videoscopic-assisted mediastinal lymph node dissection (VATS MLND) were compared to the standard surgical technique in an experimental study. METHODS: Right upper MLND--together with upper lobectomy in half of the cases--was performed in ten large white pigs. Six animals were operated using VATS (group 1), four using conventional open techniques (group 2). After 1 week, the animals were sacrificed and the mediastinum was assessed for remaining lymph nodes. RESULTS: All animals survived without intra- or post-operative complications. There was no significant difference in the operation time between the two groups (3.2 +/- 0.8 vs 3.2 +/- 0.2 h). The number of mediastinal lymph nodes harvested was 9.5 +/- 2.7 in group 1 and 11.5 +/- 0.5 in group 2 (n.s.). The post-mortem assessment of the mediastinum showed in two animals of group 1 and in two animals of group 2 that one lymph node was left behind. In addition, in one animal of group 1 four small retrotracheal lymph nodes were found. CONCLUSIONS: VATS MLND can be accomplished without morbidity and is as radical as that achieved with conventional surgery in the paratracheal and peribronchial areas in this experimental setting. However, retrotracheal lymph node dissection might not be as complete as achieved by conventional surgery.

Animals↗
PubMed1996

Descending necrotizing mediastinitis: surgical treatment via clamshell approach.

BACKGROUND: Descending necrotizing mediastinitis requires an early and aggressive surgical approach to reduce the high morbidity and mortality associated with this disease. The clamshell incision has provided excellent exposure of the entire mediastinum and both pleural cavities and was assessed in patients suffering from descending necrotizing mediastinitis. METHODS: Three patients with descending necrotizing mediastinitis and bilateral pleural empyema due to invasive streptococcal infections were operated on with this method. Radical debridement of the mediastinum and bilateral decortication was performed through a clamshell incision, including pericardiectomy in 2 patients. All patients received initially a high dose of antibiotic regimen, 2 had bilateral chest tube drainage, and 1 had mediastinal drainage and pleural debridement via cervical mediastinotomy and thoracoscopy, respectively. All these measures alone, however, failed to control the disease. RESULTS: The clamshell incision offered an excellent exposure for bilateral decortication and debridement of the entire mediastinum including pericardiectomy. One patient, who was referred in critically ill condition, died of multiorgan failure in the postoperative period. The remaining 2 patients recovered without further interventions and without evidence of phrenic nerve palsy, sternum osteomyelitis, or sternal override. CONCLUSIONS: The clamshell approach offers an excellent exposure for a complete one-stage surgical treatment with mediastinal debridement and bilateral decortication in patients suffering from descending necrotizing mediastinitis in the absence of profound septic shock.

Adolescent↗
PubMed1996

A case of acute mesenteric ischemia that responded to a combined treatment concept.

Acute mesenteric ischemia (AMI) is still associated with a high mortality rate. Early diagnosis and treatment are mandatory since irreversible bowel damage occurs within a few hours of total ischemia. Reactive vasoconstriction, high postoperative vascular reocclusion rate and the release of toxic substances from the damaged bowel followed by bacterial translocation are all part of the disease process. A combined treatment plan for AMI devides to combat the unrelenting disease process on different levels involving early operation, perioperative intraarterial fibrinolytic and vasodilative treatment and anticoagulation, selective small bowel decontamination and mandatory second look operation is presented. The rationale of this concept and its successful outcome in a highly complex case are discussed.

Adult↗
PubMed1995

[Residual postoperative pneumothorax: harmless radiological finding or complication-prone diagnosis?].

470 patients underwent either lobectomy, bilobectomy or decortication at our institution between 1980 and 1991. A residual postoperative pneumothorax was observed in 20.7% of the patients at discharge after removal of the chest tubes. There was no significant correlation between the development of a residual postoperative pneumothorax and the patient's age and gender, the type of operation (lobectomy vs bilobectomy vs decortication) and the date of operation (as related to the introduction of stapling devices). This residual postoperative pneumothorax at discharge resolved without any further treatment in 95% of the patients during follow-up. Complete regression was observed in 91% of the patients within one year after the operation and the duration of regression did not correlate with the size of the pneumothorax at discharge. No empyema was observed in any patient with residual pneumothorax during follow-up, which also holds true for patients who underwent resection or decortication for inflammatory disease. We conclude that there is no need for treatment of residual postoperative pneumothorax, either with space-filling maneuvers at the initial operation or repeat chest tube insertions during follow-up, provided there is no evidence of lung collapse.

Female↗
PubMed1995

Free latissimus dorsi flap for chest wall repair after complete resection of infected sternum.

BACKGROUND: Radical debridement, followed by muscle flap cover, has significantly reduced morbidity and mortality of infected sternotomy wounds. The pectoralis major, rectus abdominis, and greater omentum flaps are most commonly used, whereas the latissimus dorsi muscle is rarely employed. METHODS: In 7 patients with persistent infection and necrosis of the sternum, radical and extensive debridement including the sternum, costochondral arches, manubrium and sternoclavicular joints was performed. A free latissimus dorsi flap was used for soft tissue reconstruction without additional stabilization of the chest wall. RESULTS: All flaps survived without revision of the anastomosis. In the follow-up period (22 months to 5 years) no recurrent infection was observed. Three patients died during the study period (3 to 24 months after operation) due to causes not related to sternum operation. No additional weakness, pain, or restricted movements of the shoulders due to missing sternum was observed. CONCLUSIONS: Our findings suggest that the use of free latissimus dorsi flap after complete sternectomy for infection has several advantages: it provides abundant tissue to allow radical and extensive debridement, obliterates completely the dead space, and helps to control infection. Even without additional chest wall reconstruction it gives enough stability to allow pain-free normal daily activities.

Aged↗
PubMed1995

[Invasive diagnosis of mediastinal space-occupying lesions. On differential indications between cervical mediastinoscopy, parasternal mediastinotomy and video thoracoscopy].

The role of video-thoracoscopy (VT) as an invasive diagnostic procedure for mediastinal lesions not reachable by cervical mediastinoscopy (CM) has still to be defined, particularly with regard to parasternal mediastinotomy (PMT). Diagnostic efficiency and morbidity of the three methods were assessed and compared in a consecutive series over a 18 months-period after determination of a new diagnostic strategy. Among 77 interventions in 73 patients the following distribution of the methods referred was achieved: 42 CM (paratracheal and anterior subcarinal biopsies), 17 PMT (biopsies of anterior mediastinal lesions) and 18 VT (3 paratracheal, 3 posterior subcarinal, 3 anterior, 5 aortico-pulmonary window, 4 posterior biopsies or resections). All procedures were performed in general anesthesia for VT the double-lumen technique was used. Drains could be removed not later than the second postoperative day. In 7/17 cases of PMT the pleural space was opened and drained. Mean operation time (incl. waiting period for intraoperative frozen section and complete resection in a few cases) was 77 (45-100) min for VT, 49 (10-180) min for PMT and 41 (20-105) min for CM. Histological diagnosis of biopsy specimens were conclusive in all VT cases, in 15/17 PMT (88%) and in 37/42 CM (88%). Two major complications occurred: one recurrent nerve palsy following VT-resection of a neurinoma originating from the recurrent nerve itself; in a second patient submitted to mediastinoscopic biopsy, venous bleeding had to be managed by surgical sternotomy. CM as the most approved method for paratracheal and anterior subcarinal biopsies has not lost its importance. PMT as a simple and usually extrapleural intervention can further be advocated for anterior mediastinal lesions. VT turns out to be rather a complementary than a competitive invasive mediastinal diagnostic procedure and is regarded as method of choice for diagnostic approach to posterior, posterior subcarinal and aorticopulmonary lesions.

Adolescent↗
PubMed1994

Parallel assessment of glutathione-based detoxifying enzymes, O6-alkylguanine-DNA alkyltransferase and P-glycoprotein as indicators of drug resistance in tumor and normal lung of patients with lung cancer.

The levels of several potential indicators of drug resistance were measured in tumor and corresponding normal tissue of 55 untreated patients with lung cancer. The resistance parameters include glutathione (GSH) level, activities of the enzymes glutathione transferase (GST), glutathione peroxidase (GPx) and O6-alkylguanine-DNA alkyltransferase (ATase), as well as expression of P-glycoprotein (Pgp). Median values of GSH, GST and GPx were significantly higher in tumor than in normal tissue of non-small-cell lung cancer (NSCLC) or of small-cell lung cancer (SCLC), whereas ATase was elevated in tumor tissue of NSCLC only. Pgp expression as determined by Western blotting was significantly lower in tumor than in normal tissue of NSCLC. Resistance-parameter expression did not correlate with stage of disease or age of the patients. We found a negative correlation between smoking intensity and GSH level in normal tissue. Our findings indicate that the fundamental differences in chemosensitivity between SCLC and NSCLC cannot be explained by differences in the GSH-system or in the expression of Pgp. However, the level of ATase activity may be one of the factors responsible for the difference in chemosensitivity.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1994

Video-assisted thoracoscopic treatment of pleural empyema. A new therapeutic approach.

Pleural empyema is a disease which is not always recognized. Despite consecutive treatment and antibiotics its mortality rate is still high, especially in older patients with concomitant disease or in the case of delayed treatment. We report our experience with early video-assisted thoracoscopic surgery of pleural empyema in 13 patients, where chest tube drainage had failed. The clinical symptoms of empyema did not exceed 14 days, bacteriologic cultures were positive in 62%. In all patients the fever disappeared within 1 to 5 days (mean 3.5) post-operatively and they remained in hospital for an average of 11.5 days after video-assisted thoracoscopic surgery. Pulmonary function tests 6 months later revealed normal values without a substantial loss of lung volumes. No relapse of empyema occurred.

Adult↗
PubMed1994

Preservation of the first ray in a diabetic patient with a penetrating ulcer and arterial insufficiency by use of debridement and external fixation.

Successful preservation of the first ray was achieved in a diabetic patient with a penetrating ulcer with underlying osteomyelitis of the first metacarpophalangeal joint and arterial insufficiency. Resection of the joint followed by stabilisation using an external fixator for four weeks resulted in permanent control of infection and preservation of the toe without recurrence of osteomyelitis or ulceration. Since preservation and correct alignment of the first ray is essential for foot stability, this technique may be beneficial in young and active diabetic patients suffering from this difficult complication of their disease.

Debridement↗
PubMed1994

Intraoperative flow measurement of distal runoff: a valid predictor of outcome of infrainguinal bypass surgery.

OBJECTIVE: To assess the power of operative flow measurements in the prediction of outcome after infrainguinal bypass operations for critical ischaemia DESIGN: Open study SETTING: University department of vascular surgery SUBJECTS: 197 patients operated on for critical ischaemia between 1 January 1982 and 31 December 1989 under the care of one surgeon. INTERVENTIONS: Standard operative angiography and measurement of flow of distal runoff MAIN OUTCOME MEASURES: Patency and limb salvage RESULTS: All patients were followed up prospectively until 31 March 1991 or death. The estimated 5 year rates of primary patency and limb salvage were 0.75 and 0.86, respectively. Multivariate analysis showed that flow measurement was the most powerful predictor of graft patency (p = 0.0003) and limb salvage (p = 0.004) of all factors studied, including angiography. Irrespective of the site of distal anastomosis no polytetrafluoroethylene (PTFE) graft remained patent if the flow was less than 50 m/minute, whereas vein grafts remained patent if the flow was as little as 10 ml/minute. CONCLUSIONS: Flow is easy to measure and is a better predictor of outcome than angiography. Decisions about grafting should rely on flow measurements if there is any doubt about patency or limb salvage, particularly if a PTFE graft is going to be used.

Aged↗
PubMed1994

[Surgery of lung tumors].

Indeterminate solitary pulmonary nodules deserve prompt histologic confirmation, which is easily and efficiently achieved by thoracoscopic wedge resection. Patients with stage I to IIIa NSCLC are best treated by complete tumor resection (lobectomy/pneumonectomy) and mediastinal lymph node dissection. However, induction (radio)chemotherapy followed by surgical resection is increasingly performed for locally advanced NSCLC, since this offers far better results than surgery or radiotherapy per se, especially for bulky N2 disease. Surgical resection of pulmonary metastases is certainly indicated in selected patients, and the outcome is strongly related to the completeness of tumor removal. Patients with peripheral solitary lung metastases are increasingly treated by thoracoscopic wedge resection, followed by CT-scans at regular intervals.

Carcinoma, Non-Small-Cell Lung↗
PubMed1993

Photodynamic therapy with m-tetrahydroxyphenylchlorin in vivo: optimization of the therapeutic index.

The therapeutic index of meta-tetrahydroxyphenylchlorin-mediated photodynamic therapy (mTHPC-PDT) was assessed in BALB/c nude mice bearing human malignant mesothelioma xenografts. Equal doses of 650 nm laser light were delivered to the tumour and to an equal-sized area of the hind leg (control site) after i.p. administration of mTHPC. Twenty-one groups of 6 animals each were treated under various drug-light conditions and at drug-light intervals ranging from 4 hr to 6 days. After light delivery the extent of tumour necrosis and the depth of alterations in normal tissue were assessed by light microscopy of standardized histological sections. A therapeutic index (TI) of mTHPC-PDT was defined as the cross-sectional area of tumour necrosis per depth of visible tissue injury at the control site. This TI was strongly related to the conditions of treatment. In particular, it was increased by prolonging the drug-light interval up to 5 days and by increasing the dose of light for any dose of drug. The most profound increase of TI was obtained by increasing the intensity of light administered at the chosen interval while reducing the dose of drug. Our findings suggest that threshold conditions operate in PDT and have important implications for clinical application of the treatment.

Animals↗
PubMed1993

[Video-thoracoscopy diagnosis and treatment of persistent post-traumatic pneumothorax].

Despite correct chest tube drainage, 2 patients had persistent pneumothorax after blunt chest trauma and were referred for further treatment. Videothoracoscopy revealed small lung lacerations caused by rib fragments. A small wedge resection performed via thoracoscopy by the use of an endostapler resulted in immediate and permanent relief of air leakage.

Aged↗
PubMed1993

Effect of drug-light interval on photodynamic therapy with meta-tetrahydroxyphenylchlorin in malignant mesothelioma.

The influence of the time interval (TI) between drug administration and laser activation on selectivity of meta-tetrahydroxyphenylchlorin(mTHPC)-mediated photodynamic therapy (PDT) for tumour tissue was assessed in BALB/c nude mice bearing human malignant mesothelioma xenografts. Following i.p. administration of 0.3 mg/kg mTHPC, a light dose of 10 J/cm2 and 0.1 W/cm2 was delivered at 650 nm on the tumour and an equal-sized area of the hind leg after 4, 12, 24 and 36 hr and 2, 3, 4, 5 and 6 days to groups of 6 animals (surface irradiance). Then, 72 hr after light delivery, the depth of necrosis was measured in the tumour and in the skin and underlying muscle of the hind leg. Photosensitized necrosis occurred in normal tissue at TI from 4 hr to 3 days and in the tumour at TI from 12 hr to 4 days. The therapeutic ratio of mTHPC-PDT varied significantly with the time interval between drug administration and laser activation and was greatest at an interval of 3 days. mTHPC concentration was measured in 3 control unirradiated animals at all time points in normal tissues and in tumour tissue, and found to be the same in both tissues. Thus the tissue concentration of mTHPC was of limited use as regards the prediction of photosensitizing effects in the tumour model.

Animals↗
PubMed1993

Absence of rhodamine 123-photochemotoxicity in human tumor xenografts.

Rhodamine 123 (R123)-photochemotoxicity was assessed in BALB/c nude mice bearing a xenografted human squamous cell carcinoma at various power densities and wavelengths and a given incident fluence of 150 Joules/cm2. One hour before light delivery, 1 mg R123/kg was injected i.p. in 20 animals. Surface irradiance was performed on the tumor and an equal size hind leg area of 40 animals. Three groups of 10 animals were treated at 514.5 nm and 0.1 W/cm2, 1 W/cm2, and 30 W/cm2, and one at 488 nm and 30 W/cm2. In each group, five animals received R123. The R123 concentration was measured in the tumor (0.023 +/- 0.007 micrograms/g) and tumor-free tissue (0.023 +/- 0.008 micrograms/g) in three additional animals by high performance liquid chromatography 1 hour after R123-administration. Histologic assessment 72 hours after light delivery revealed no tissue damage at nonthermal power densities, either in the tumor or in the tumor-free tissue, irrespective of R123-administration. At 30 W/cm2, neither in the tumor nor in tumor-free tissues was there any significant difference in the depth of necrosis, irrespective of R123-administration and the wavelength applied. Our results question the validity of R123 as a photosensitizer, at least in this rodent tumor model.

Animals↗
PubMed1993

Experimental assessment of thrombogenicity in vascular prostheses before and during prostaglandin E1 treatment.

The effect of prostaglandin E1 (PGE1; Prostavasin), a powerful platelet blocking agent, was assessed on various new synthetic or biological prostheses in a 6-min in vivo extra corporal arterio-venous (AV) shunt. In eight anaesthetised and heparinised minipigs (weight 25.1 +/- 1.9 kg) the following materials were tested before and during PGE1 infusion (alprostadil-alpha-CD; 40 micrograms/50 ml NaCl/50 min or 0.8 microgram/min): PTFE, (Gore-tex, TW, 4 mm ID); Xenograft, Biologic (Solcograft, 5 mm ID), (non-porous) and Dacron (Atrium, 4 mm ID); polyurethane 1 (Braun-Melsungen, 4 mm ID); polyurethane 2 (S. Gogolewski, 4 mm ID), (porous). Technetium-labelled platelet deposition and blood flow were measured; morphology was assessed by scanning electron microscopy (SEM) and histology. Compared to control levels, PGE1 infusion had a significant systemic effect on mean arterial pressure required by the protocol (MAP 82.6 vs. 66.6 mm Hg; p < 0.001) and flow (173.6 vs. 134.8 mm/min; p < 0.001). Standardised platelet counts per area showed a marked overall decrease from 197 to 130 counts/min/mm2; NS). The morphological assessment by SEM showed a slight increase of surface cellular deposition (score: 6.7 vs. 8.3), the histology score being unchanged (3.9 vs. 3.7). Looking at deposition of platelets for each prosthesis, the porous materials showed a net improvement after PGE1 treatment as compared to non-porous materials. We conclude that PGE1 may be of benefit by reducing platelet deposition in synthetic porous vascular prostheses in the early phase.

Alprostadil↗