Mediastinal epithelioid hemangioendothelioma in a patient with type IV Ehlers-Danlos syndrome: a case report and review of the literature

Ehlers-Danlos syndrome (EDS) is a collection of inherited connective tissue disorders with at least 10 types, differentiated on clinical and genetic grounds. Malignancy has been described only rarely in association with the syndrome. Epithelioid hemangioendothelioma (EH) is a rare endothelial tumor, which displays clinical behavior intermediate between that of hemangioma and angiosarcoma. A case report of a 50-year-old man with type IV EDS who was extensively investigated for several years for multiple mediastinal nerve palsies and chest pain. Magnetic resonance imaging (MRI) demonstrated an anterior mediastinal mass, which at biopsy showed EH. Subsequent metastatic spread to liver and lungs is unique among reported cases of mediastinal EH. The patient experienced significant symptomatic improvement from external beam radiotherapy (RT) to the mediastinum. After metastatic disease developed, multiagent chemotherapy was administered, but without response. The literature is reviewed regarding treatment of EH and the potential problems associated with EDS. Although there appears to be no etiological association between EDS and EH, the connective tissue disease clearly contributed to a delay in diagnosis and raised concerns regarding RT tolerance. The potential predisposition to aggressive tumor invasion remains a possibility. In addition, mediastinal EH has the potential to metastasize, and in this case demonstrated resistance to a broad range of chemotherapy agents.

Fatal pulmonary toxicity resulting from treatment with gemcitabine

BACKGROUND

Pulmonary toxicity reported with gemcitabine is usually mild and self-limiting. The authors report a series of three patients who had life-threatening pulmonary toxicity after receiving gemcitabine.

METHODS

The three patients presented to two major teaching hospitals with significant pulmonary dysfunction while receiving gemcitabine. Case data were obtained from patient records. A review of the literature was done to seek reports of pulmonary toxicity with gemcitabine and cytosine arabinoside (ara-C).

RESULTS

The common features of the respiratory illnesses of the three patients in this study were tachypnea, marked hypoxemia, and an interstitial infiltrate on chest radiograph consistent with pulmonary edema. There was no evidence of underlying heart disease in any patient. In addition, there was no evidence of infection, metabolic causes, or lymphangitic carcinomatosis to explain the clinical findings. Two patients died, and postmortem examination confirmed acute RDS (respiratory distress syndrome), whereas in the third patient a transbronchial biopsy showed interstitial pneumonitis. These findings were consistent with drug-induced pulmonary toxicity. Diuretics and corticosteroids were useful measures for treating the patients' symptoms, and one patient survived after gemcitabine was withdrawn.

CONCLUSIONS

These three cases of acute RDS may be the result of a capillary leak phenomenon due to treatment with gemcitabine, as observed in patients given intermediate dose and high dose ara-C, a drug similar in structure and metabolism to gemcitabine. The authors suggest caution in repeated administration of gemcitabine to patients who develop unexplained noncardiogenic pulmonary edema. Withdrawing gemcitabine and administering corticosteroids and diuretics may help to avert a fatal outcome.

Skeletal muscle ischemia-reperfusion causes transitory increase in microvascular protein permeability

The aim of this study was to determine whether the length of ischemia in skeletal muscle influences the return of normal microvascular permeability during reperfusion in addition to influencing the size of the initial changes. In anesthetized rabbits, the transvascular clearance of labeled albumin was measured in the gastrocnemius and soleus muscles during the first, second, third, or fourth hour of reperfusion after 1, 2, 3, or 4 h of ischemia. The size of the increases in albumin clearance, tissue water, and myeloperoxidase activity during the first hour of reperfusion was dependent on the length of ischemia. The return of the albumin clearance to control values during the fourth hour of reperfusion was independent of the length of ischemia. Tissue water, extravascular mass of native albumin, and myeloperoxidase activity remained elevated during the 4 h of reperfusion. After 4 h of ischemia, the solvent-drag reflection coefficient for albumin was significantly less than control during the first hour of reperfusion. The value during the fourth hour of reperfusion was not significantly different from control. These results suggest that the inflammatory mediators producing a change in permeability are washed out of the microvasculature during the first few hours of reperfusion.

Australian multicentre phase II trial of paclitaxel in women with metastatic breast cancer and prior chemotherapy

OBJECTIVE

To determine the efficacy and safety of paclitaxel given as a three-hour infusion in patients with metastatic breast cancer which had progressed despite hormonal therapy and/or chemotherapy.

DESIGN AND SETTING

Multicentre phase it trial undertaken in five major centres or hospitals in Sydney, Melbourne and Adelaide.

PATIENTS AND METHODS

50 patients with clinically or radiologically measurable or evaluable metastatic breast cancer recruited between March and July 1993. All had received prior chemotherapy, with subsequent disease progression.

INTERVENTION

Paclitaxel (Anzatax, Faulding) was given at a dose of 175 mg/m2 intravenously over three hours every three weeks for up to nine courses.

MAIN OUTCOME MEASURES

Response rate (partial or complete); duration of progression-free survival; duration of survival; and adverse reactions.

RESULTS

Patients had a median age of 51 years; 62% had received at least two prior drug regimens for metastatic breast cancer and 48% had anthracycline-resistant tumours. A median of six paclitaxel courses was given per patient. Overall response rate was 18% (95% confidence interval [95% CI], 9%-31%), with complete responses in four patients (8%). In patients with anthracycline-resistant tumours, response rate was 25% (95% CI, 10%-47%). Response was not influenced by extent of prior treatment. Estimated median progression-free survival was 4.1 months (95% CI, 3.2-6.0 months) and estimated median survival was 6.3 months (95% CI, 6.2-10.3 months). Treatment was well tolerated, with neutropenia the major toxic effect.

CONCLUSIONS

Paclitaxel (three-hour infusion) has significant activity in heavily pretreated patients with metastatic breast cancer, including anthracycline-resistant tumours.

Patterns of alternative medicine use by cancer patients

OBJECTIVE

To assess the patterns of alternative medicine use in patients of a public hospital oncology unit, and to compare patients' experience of alternative with conventional medicine.

DESIGN AND SETTING

Self-administered questionnaire survey of cancer patients attending specialist consulting rooms at the Royal North Shore Hospital and the Oncology Outpatient Clinic at Port Macquarie Base Hospital during August 1995.

PARTICIPANTS

507 patients attended the clinics; 335 (66%) returned questionnaires, of which 319 (62%) were sufficiently complete for analysis.

MAIN OUTCOME MEASURES

Expectations of and satisfaction with both conventional and alternative treatment, use of alternative treatment, and patient characteristics associated with this use.

RESULTS

Expectations of and satisfaction with both conventional and alternative treatment were very high. Alternative treatments (most commonly dietary and psychological methods) were used by 21.9% of patients. Median annual cost of alternative therapy was $530, with most patients reporting "value for money". Younger age and being married were positively associated, and satisfaction with conventional treatment was negatively associated, with alternative medicine use; 40% of patients did not discuss alternative medicine with their physician.

CONCLUSIONS

A significant proportion of cancer patients use one or more forms of alternative therapy. The use of alternative therapy may reflect on deficiencies in the current standard of care.

Selective effect of high arterial pressure in hypertension upon inhibition of cGMP versus cAMP mediated vascular relaxation

We tested the hypothesis as to whether elevated arterial pressure in hypertension alters cGMP, or cAMP, mediated vasorelaxation. Relaxation to nitroglycerin and isoproterenol was determined in isolated aortic rings from one-kidney, one clip hypertensive (1K1C), coarctation hypertensive (CH) and normotensive control (C) rats. Thoracic aortas from 1K1C and CH rats, as well as abdominal aortas from 1K1C rats, but not abdominal aortas from CH rats were exposed chronically (4-6 weeks) to elevated arterial pressure. Sensitivity of rings with and without endothelium to nitroglycerin was suppressed significantly only in vessels exposed chronically to high arterial pressure. Impaired sensitivity to nitroglycerin in abdominal rings from 1K1C rats could not be abolished by exposure to 100 uM L-arginine, the substrate for production of NO by endothelial nitric oxide synthase, or 100 uM L-cysteine, the source of thiol groups required for the production of nitric oxide from nitroglycerin. Maximum relaxation to isoproterenol was impaired significantly in thoracic and abdominal rings, with and without endothelium, from 1K1C and CH rats. Relaxation to 8-bromo-cGMP and dibutyryl cAMP was similar in abdominal rings from all groups. We conclude that impaired vasorelaxation to nitroglycerin and isoproterenol in hypertension involves mechanisms prior to activation of vascular smooth muscle cGMP-dependent and cAMP-dependent protein kinase, respectively. Impaired cGMP, but not cAMP, mediated relaxation of aortas appears to result from their exposure to high arterial pressure per se. This effect does not appear to involve the vascular endothelium or vascular sources of thiols, but rather may reflect an effect of high arterial pressure to impair the ability of the artery to respond to nitric oxide derived from nitroglycerin.

Cloning and structure of delta-latroinsectotoxin, a novel insect-specific member of the latrotoxin family: functional expression requires C-terminal truncation

The venom of the black widow spider (BWSV) (Latrodectus mactans tredecimguttatus) contains several potent, high molecular mass (>110 kDa) neurotoxins that cause neurotransmitter release in a phylum-specific manner. The molecular mechanism of action of these proteins is poorly understood because their structures are largely unknown, and they have not been functionally expressed. This study reports on the primary structure of delta-latroinsectotoxin (delta-LIT), a novel insect-specific toxin from BWSV, that contains 1214 amino acids. delta-LIT comprises four structural domains: a signal peptide followed by an N-terminal domain that exhibits the highest degree of identity with other latrotoxins, a central region composed of 15 ankyrin-like repeats, and a C-terminal domain. The domain organization of delta-LIT is similar to that of other latrotoxins, suggesting that these toxins are a family of related proteins. The predicted molecular mass and apparent mobility of the protein (approximately 130 kDa) encoded in the delta-LIT gene differs from that of native delta-LIT purified from BWSV (approximately 100 kDa), suggesting that the toxin is produced by proteolytic processing of a precursor. MALDI-MS of purified native delta-LIT revealed a molecular ion with m/z+ of 110916 +/- 100, indicating that the native delta-LIT is 991 amino acids in length. When the full-length delta-LIT cDNA was expressed in bacteria the protein product was inactive, but expression of a C-terminally truncated protein containing 991 residues produced a protein that caused massive neurotransmitter release at the locust neuromuscular junction at nanomolar concentrations. Channels formed in locust muscle membrane and artificial lipid bilayers by the native delta-LIT have a high Ca2+ permeability, whereas those formed by truncated, recombinant protein do not.

An open multicentre study of tropisetron for cisplatin-induced nausea and vomiting

OBJECTIVES

(i) To assess the efficacy and tolerability of tropisetron when used for acute and delayed cisplatin-induced emesis. (ii) To investigate whether dexamethasone added to tropisetron improves the control of emesis for patients who do not achieve a complete response to tropisetron alone. (iii) To assess sex of the patient and alcohol intake as prognostic factors for nausea and vomiting.

DESIGN

A prospective open label phase II trial over one or two cycles of chemotherapy. Data collection was based on observed response and patients' self-reporting.

SETTING

Twenty Australian tertiary care hospitals in 1994.

PATIENTS

102 male and female patients from 18 to 75 years with histologically confirmed malignancy receiving their first chemotherapy containing > or = 50 mg/m2 cisplatin.

INTERVENTION

In Cycle 1 tropisetron 5 mg was given intravenously before chemotherapy on Day 1, then 5 mg orally before breakfast on Days 2 to 6. In Cycle 2, dexamethasone 20 mg intravenously on Day 1, then 8 mg orally on Days 2 to 6 could be added to tropisetron if a complete antiemetic response had not been achieved in Cycle 1.

MAIN OUTCOME MEASURES

Number of vomiting episodes and severity of nausea for 6 days after chemotherapy; severity of side effects; patient satisfaction with chemotherapy treatment; oestradiol levels in women; and past alcohol consumption in men and women.

RESULTS

(i) The complete response rate (CR) for acute emesis in Cycle 1 was 64% (95% confidence interval [CI], 54%-72%), with 84% (95% CI, 76%-90%) having < or = 2 vomits. The CR for delayed emesis was 24% (95% CI, 17%-32%). The CR for acute nausea was 56% (95% CI, 47%-66%), with 97% (95% CI, 91%-99%) having < or = 2 nausea episodes. The CR for delayed nausea was 21% (95% CI, 14%-30%). Seventy-one patients received Cycle 2. The main side effects were headache (20 patients) and constipation (16 patients). The control of acute emesis was rated as "good" or "very good" by 68% of investigators; 85% rated the tolerability of treatment as "good" or "very good". Treatment was rated as "very satisfactory" or "satisfactory" by 52% of patients. (ii) The CR for acute emesis with dexamethasone added was 78% (95% CI, 64%-88%). (iii) Women with lower oestradiol levels had better control of emesis, although this difference was not statistically significant. Chronic alcohol intake and binge drinking were strongly associated with a complete acute antiemetic response.

CONCLUSIONS

Tropisetron was effective for acute cisplatin-induced emesis; adding dexamethasone enhanced this response. Both single and combined therapy had less effect on delayed emesis. The impact of alcohol on control of emesis is a chronic rather than acute phenomenon which requires prospective testing.

Long-term follow-up of a randomised trial of combined chemoradiotherapy induction treatment, with and without maintenance chemotherapy in patients with small cell carcinoma of the lung

The toxicity and efficacy of concomitant chemotherapy and radiotherapy as induction therapy was evaluated in patients with previously untreated small cell carcinoma of the lung (SCLC), and in responding patients the value of maintenance chemotherapy was examined. 202 patients received induction chemotherapy with cisplatin and etoposide (EP), in combination with cranial and local radiotherapy. 85 patients (42%) developed grades III and IV myelosuppression, the main toxicity of induction treatment. Of the 154 responding patients, 129 were randomised to maintenance chemotherapy with vincristine, doxorubicin and cyclophosphamide (VAC) or no further treatment. The response rate for the limited disease patients (LD) was 87%, 62% achieving a complete response (CR) and the response rate for extensive disease patients (ED) was 68%, with 26% achieving a CR. 17 patients (11%) completed 10 courses of maintenance chemotherapy. 32 patients (57%) developed grade III and IV neutropenia. Median survival for all patients was 53 weeks (LD, 70 weeks; ED, 42.5 weeks). There was no significant difference in overall survival (OS) or disease-free survival (DFS) in the two randomisation arms. This study shows that EP combined with radiotherapy is an effective induction regimen in SCLC. Maintenance chemotherapy with VAC is not associated with increased survival but has significant toxicity after such induction treatment.

Phase II trial of a 3-hour infusion of paclitaxel in previously untreated patients with advanced non-small-cell lung cancer

PURPOSE

To determine the antitumor activity and toxicity of paclitaxel administered as a 3-hour infusion in patients with advanced non-small-cell lung cancer (NSCLC).

PATIENTS AND METHODS

Fifty-one patients with advanced measurable or assessable NSCLC and performance status 0 to 2 who had not received prior chemotherapy were treated with paclitaxel 175 mg/m2 over 3 hours with premedication. Cycles were repeated every 3 weeks for a maximum of nine cycles. Most patients had prior radiotherapy (57%), extrathoracic metastatic disease (65%), and measurable disease (75%). Twenty-two percent had previously untreated stage III disease.

RESULTS

The objective response rate was five of 51 (10%; 95% confidence interval, 3% to 21%). No subgroup with a higher response rate could be identified. There were no complete responses (CRs) and all responses lasted less than 5 months. Treatment was well tolerated with brief World Health Organization (WHO) grade IV neutropenia in only 16% of patients. Grade III/IV myalgia/athralgia occurred in 22% of patients. No significant hypersensitivity reactions occurred.

CONCLUSION

The antitumor activity of this dose and schedule appears inferior to that reported in previously published phase II trials in NSCLC that used higher doses of paclitaxel infused over 24 hours, although confidence intervals for response overlap. Determining the optimal dose and schedule for using paclitaxel in NSCLC requires further investigation, and these results should caution against using shorter infusions outside appropriate clinical trials.

Chromosomal localisation, inducibility, tissue-specific expression and strain differences in three murine peroxisome-proliferator-activated-receptor genes

Three murine peroxisome-proliferator-activated-receptor (PPAR) genes were localised to chromosome 15 (PPAR alpha), chromosome 17 (PPAR beta) and chromosome 6 (PPAR gamma). The expression of the three PPAR RNAs was determined using a specific RNase protection assay. In liver RNA, PPAR alpha was expressed at the highest level, with 20-fold lower levels of PPAR beta, and very low levels of PPAR gamma. The three PPAR RNAs showed no sex-specific differences in expression, and the levels of these transcripts were unaffected by treatment of mice with testosterone or the potent peroxisome proliferator, methylclofenapate. In agreement with this data, the level of PPAR alpha protein in liver was unchanged after treatment of mice with methylclofenapate. Investigation of the tissue-specific distribution revealed that the PPAR alpha RNA was expressed at highest levels in liver, to moderate levels in kidney and brown adipose tissue, and at low levels elsewhere. PPAR beta was expressed at moderate levels in liver, and lower levels in other tissues, including brown adipose tissue. In contrast, PPAR gamma RNA was expressed at low levels in liver or epididymal white adipose tissue and at very low levels elsewhere, but was expressed at high levels in brown adipose tissue. The tissue distribution of these receptors suggests an important role in lipid metabolism and toxicity for individual members of the PPAR family. The expression of PPAR alpha and PPAR beta RNAs was examined in 13 strains of mice, and the levels of expression varied within a fourfold range. Polymorphism in the size of PPAR alpha RNA from Swiss-Webster mice was detected, and shown to be due to a 2-bp mutation in the 3' non-coding region of PPAR alpha in Swiss Webster mice.

Noradrenergic vasorelaxation of porcine coronary arteries is enhanced by direct, acute exposure to 17 beta-estradiol

1. We tested whether responses of isolated coronary arteries to adrenergic agents are altered by overnight (18-22 hr) or acute exposure to physiological levels of 17 beta-estradiol. 2. Sensitivity to relaxation by norepinephrine (-log M ED50) was enhanced significantly in isolated arteries after acute exposure to 10(-9) M 17 beta-estradiol. Neither alpha-adrenergic contraction to norepinephrine, nor beta-adrenergic relaxation to isoproterenol was affected by acute exposure to 17 beta-estradiol. 3. Responses of coronary arteries to relaxation or contraction by norepinephrine, as well as relaxation by isoproterenol, were not altered by overnight incubation with 17 beta-estradiol or by removal of the endothelium. 4. We conclude that relaxation of coronary arteries by norepinephrine is enhanced by acute, direct exposure to physiological levels of 17 beta-estradiol. This enhancement does not result from effects of estradiol to suppress alpha-adrenergic contraction to norepinephrine or increase coronary beta-adrenergic receptor sensitivity.

Effect of chronic high pressure on transient and tonic vascular contractions to serotonin in hypertension

This study examined whether vascular contractions related to the extracellular or intracellular pools of calcium activated by serotonin are altered by high arterial pressure in chronic hypertension. Coarctation hypertensive (CH), sham normotensive control (C), and one-kidney, one-clip hypertensive rats (1K1C) were used. Tail systolic, carotid, and femoral arterial pressures were measured. Thoracic aortas from 1K1C and CH rats, as well as abdominal aortas from 1K1C rats, but not abdominal aortas from CH rats were exposed chronically to elevated arterial pressure. Isolated rings of thoracic and abdominal aortas from all groups were suspended in muscle baths for isometric force recordings. After cellular calcium depletion, dose-response curves to extracellular calcium, in the presence of 10(-5) mol/L serotonin, were unchanged in thoracic or abdominal aortas among the three groups. In the presence of submaximum levels of serotonin (2 x 10(-6) mol/L), thoracic and abdominal rings without endothelium and abdominal rings with endothelium from the three groups showed similar responses to extracellular calcium. Such responses were significantly depressed in thoracic rings with endothelium from CH and 1K1C rats. Transient contractions attributable to release of an intracellular calcium pool by 10(-5) mol/L serotonin were enhanced significantly in hypertensive thoracic and abdominal aortas from 1K1C rats, when the pool was loaded with 0.25, 0.5, 1.0, 2.0, or 4.0 mmol/L CaCl2, as well as in hypertensive thoracic aortas from CH rats when the pool was loaded with 1.0, 2.0, or 4.0 mmol/L CaCl2, but not in normotensive abdominal aortas from CH rats at any calcium-loading concentration. Similar results were observed in aortas from C, CH, and 1K1C rats loaded with 1.0 or 2.0 mmol/L CaCl2 and stimulated with 2 x 10(-6) mol/L serotonin. Endothelial removal had no effect on these calcium-release contractions in abdominal aortas from any group, but enhanced contractions in thoracic aortas of 1K1C rats. In rings loaded with 2.0 mmol/L CaCl2, 2-nitro-4-carboxyphenyl-N,N-diphenylcarbamate inhibited contractions attributable to release of cellular calcium stores to a similar extent in C, CH, and 1K1C rats. This study suggests that serotonin-stimulated intracellular calcium-dependent aortic contractions are enhanced by elevated pressure in renal hypertensive rats.

Estrogen pretreatment directly potentiates endothelium-dependent vasorelaxation of porcine coronary arteries

We tested whether vasorelaxation of coronary arteries is altered after overnight (18-22 h) exposure to physiological levels of 17 beta-estradiol. Ring segments of left circumflex coronary artery from six female and six castrated male pigs were incubated in vials of sterile Dulbecco's modified Eagle's medium with 1 nM 17 beta-estradiol, 1 nM 17 beta-estradiol + 10 nM tamoxifen, 1 nM 17 alpha-estradiol, or estrogen vehicle (ethanol) under normoxic conditions in an O2-CO2 incubator at 37 degrees C for 18-22 h. Coronary rings, with and without endothelium, were then suspended in vessel baths for measurement of isometric force. Vasorelaxation responses to the calcium ionophore A-23187, ADP, and nitroglycerin were examined in the rings after prostaglandin synthesis blockade and precontraction with U-46619. Sensitivity to A-23187 (-log M concentration required for 50% of maximal relaxation) was significantly enhanced in coronary rings with endothelium from females and castrated males when rings were incubated with 17 beta-estradiol but not when they were incubated with 17 alpha-estradiol or 17 beta-estradiol+tamoxifen. Acute (2h) exposure of coronary arteries to 1 nM 17 beta-estradiol did not alter responses to A-23187. 17 beta-Estradiol (1 nM) was not itself directly vasoactive in coronary arteries with or without prior incubation with the steroid. Vasorelaxation of rings with and without endothelium to ADP and nitroglycerin was not significantly different among the treatment groups. Relaxation to A-23187, but not ADP, was abolished by removal of the endothelium or exposure to 100 microM NO2-L-arginine.(ABSTRACT TRUNCATED AT 250 WORDS)

Bone presentation of non-Hodgkin's lymphoma: experience at the Royal North Shore Hospital, Sydney; highlighting primary bone lymphoma

BACKGROUND

Primary lymphoma of bone (PLB) is a rare form of extranodal lymphoma. Between 1975 and 1992 39 patients with lymphoma presenting in bone were seen at the Royal North Shore Hospital (RNSH), Sydney. Of these, 12 (31%) had truly localised disease (Stage IE).

AIMS

Patients were studied retrospectively to determine the prognostic significance of bony involvement per se versus involvement of a single bony site, and to determine the impact of treatment modality on outcome.

METHODS

The 39 patients were divided into three groups according to extent of disease; single osseous site (Stage IE), multifocal bone, and bone plus visceral and/or nodal disease. Kaplan-Meier survival curves were constructed, and five year actuarial survival stated. Cox regression analysis was used to determine hazard ratios. Overall survival was used as the end-point.

RESULTS

A trend for better survival was noted with Stage IE disease. Multifocal and disseminated disease appeared to have a poorer outcome when assessed by hazard ratio, with a value of 3 (95% CI 0.87-10.4; p = 0.08), compared to unifocal disease. Radiotherapy alone was as effective as combined modality treatment although patient numbers were too small for statistical confirmation.

CONCLUSIONS

The stage of lymphoma, rather than bony involvement per se, seems to have more prognostic importance. Radiotherapy alone offered equivalent results to combined modality treatment in this series.

Specificity and sensitivity of immunocytochemistry for detecting P-glycoprotein in haematological malignancies

AIMS

To determine the optimal working conditions of the alkaline phosphatase-antialkaline phosphatase (APAAP) method to establish a specific and sensitive assay for the detection of low numbers of MDR positive cells in patients with hematological malignancies.

METHODS

Three monoclonal antibodies (C-219, JSB-1, MRK-16) were used for the detection of P-glycoprotein (P-gp) in cell lines and in samples from 43 patients with haematological malignancies. The results of the APAAP method were compared with western blotting for specificity and sensitivity.

RESULTS

Excellent correlation was obtained between optimised APAAP and western blotting, except in the case of multiple myeloma. JSB-1 seemed to be the more useful monoclonal antibody for the APAAP which was more sensitive than western blotting in its ability to detect single P-gp positive cells.

CONCLUSIONS

Methods for P-gp detection, as defined by multidrug resistant (MDR) cell lines, are not necessarily optimal and specific for clinical samples and may lead to higher false positive and negative results, according to the conditions and the monoclonal antibodies used.

Isoproterenol decreases protein permeability in edematous isolated rabbit lungs: estimation of PS and sigma

The objective of the present study was to determine whether the ability of the beta-adrenergic agonist isoproterenol to attenuate pulmonary edema occurs via a permeability and/or hemodynamic mechanism. In isolated perfused rabbit lungs, the restrictive property of the vascular barrier to the movement of fluid and protein was assessed by measurements of the capillary filtration coefficient (Kf) and the transvascular clearance of 125I-labeled albumin, respectively. Regression analysis of albumin clearance vs. transvascular fluid flux was performed to estimate the permeability-surface area product (PS) and the reflection coefficient (sigma) by use of the linear or nonlinear flux equation. Arterial, capillary, and venous pressures and resistances, weight gain, and the wet-to-dry weight ratio were also assessed. Isoproterenol (8 ng.ml-1.min-1) attenuated the arachidonic acid (4 mg)-induced increases in fluid flux, wet-to-dry weight ratio, albumin clearance, and PS and the decrease in sigma. Isoproterenol had no effect on the increase in Kf, and there was no correlation between capillary pressure and fluid flux in any of the four groups. Regression analysis revealed that the non-linear flux equation provided estimates of PS and sigma that more accurately described the statistical differences in albumin clearance among the groups studied than the linear flux equation. These findings demonstrate that isoproterenol attenuated the increased transvascular flux of albumin in edematous lungs by modifying the protein permeability of the vascular barrier.