PubMed Health⌕ Search

Biomedical subjects

A Tubaro

Publications and source records attributed to A Tubaro.

At least 37 records · Page 2Linked to original sources
PubMed2001

A prospective study of the safety and efficacy of suprapubic transvesical prostatectomy in patients with benign prostatic hyperplasia.

PURPOSE: We investigate the safety and efficacy of suprapubic transvesical prostatectomy, and the change in bladder wall thickness after surgery. MATERIALS AND METHODS: We conducted a prospective 1 center study of 32 consecutive patients who underwent transvesical prostatectomy from December 1996 to March 1997 for benign prostatic hyperplasia with large prostate volume, who were followed for 1 year. Pressure flow study and transrectal sonography were performed at baseline and repeated at 6 months. Bladder wall thickness was measured at baseline and regular intervals postoperatively. A morbidity questionnaire was completed during the first 6 weeks after surgery. RESULTS: An average of 63 gm. prostate adenoma were enucleated at surgery. An indwelling catheter was required for an average plus or minus standard deviation of 5.4 +/- 2.6 days after treatment. The International Prostate Symptom Score decreased from 19.9 +/- 4.4 to 1.5 +/- 2.7 and the quality of life score decreased from 4.9 +/- 1.0 to 0.2 +/- 0.4 at year 1, respectively. Maximum flow rate improved from 9.1 +/- 5.3 to 29.0 +/- 8.9 ml. per second. Residual urine decreased from 128 +/- 113 to 8 +/- 18 ml. Before surgery 30 patients had obstruction and 2 were in the equivocal zone of the International Continence Society nomogram. At 6 months after prostatectomy 30 patients did not have obstruction, and 2 who were subsequently operated on for bladder neck sclerosis were equivocal and had obstruction, respectively. No patient had significant postoperative bleeding and no heterologous blood transfusions were required. There were 4 men who had urinary tract infection and 1 who had wound infection. A slight decrease in erectile function was observed 6 weeks postoperatively, and no change in patient libido and quality of sex life was reported. The total complication rate was 31.3%. The bladder was unstable in 7 men before and 3 after surgery. A significant decrease in bladder wall thickness was observed from 5.2 +/- 0.7 at baseline to 2.9 +/- 0.9 mm. at year 1 postoperatively. CONCLUSIONS: Our study confirms the excellent clinical outcome of transvesical prostatectomy, and rapid improvement of most subjective and objective parameters during the 4 weeks after surgery. Bladder hypertrophy appears to be significantly reduced after prostate surgery. The urodynamic results in patients who underwent open surgery probably represent the maximum obtainable relief of obstruction and should be considered the reference standard to which all other treatments, including transurethral resection, should aspire.

Aged↗
PubMed2001

A probability based system for combining simple office parameters as a predictor of bladder outflow obstruction.

PURPOSE: We explored the relationships of office assessment of lower urinary tract symptoms, transrectal ultrasound measurement and the bladder outlet obstruction index, as derived from pressure flow studies. We also developed and validated a multivariate analysis for predicting the bladder outlet obstruction index. MATERIALS AND METHODS: We evaluated 384 men with lower urinary tract symptoms using the International Prostate Symptom Score, maximum urine flow, post-void residual urine, transrectal ultrasound and urodynamic studies. Data were analyzed by multiple linear regression with continuous variables. A simple algorithm, that is the predicted bladder outlet obstruction index, was created using the best fit variables identified from a derivation set and assessed in a separate validation set. The predicted index was applied to predict the probability of actual obstruction according to office parameters. RESULTS: Maximum urine flow and total prostate volume predicted the bladder outlet obstruction index most completely (adjusted R2 = 0.50, F 75.9, p <0.0001), while other variables were not helpful. These variables were used to create the predicted bladder outlet obstruction index algorithm, antilog10 (2.21 - 0.50 log maximum urine flow + 0.18 log total prostate volume) - 50. In the 42% of patients with a predicted index of greater than 40 there was a 92% risk or positive predictive value of equivocal or worse obstruction, whereas a predicted index of less than 20 in 23% indicated a 4% risk of significant obstruction. CONCLUSIONS: The bladder outlet obstruction index can be predicted from maximum urine flow and prostate volume. Development of the predicted bladder outlet obstruction index algorithm enables the mathematical prediction of obstruction from these simple measures. Using the predicted bladder outlet obstruction index clinicians can determine the risk of obstruction in individuals. In 65% of patients we predicted equivocal or worse obstruction with greater than 90% confidence.

Aged↗
PubMed2000

Relation between intraprostatic temperature and clinical outcome in microwave thermotherapy.

PURPOSE: The study was designed to explore the relation between prostatic temperature and the clinical outcome of transurethral microwave thermotherapy (TUMT). PATIENTS AND METHODS: Forty-nine patients with symptomatic benign prostatic hyperplasia (BPH) were treated. Baseline evaluation included Madsen score, flowmetry, and pressure-flow study. Two fiberoptic thermosensors were placed in the prostate targeted to the region 10 and 20 mm below the bladder neck and 5 to 15 mm lateral to the prostatic urethra. The TUMT was carried out using either the low-energy (2.0) or high-energy (2.5) Prostasoft program. Follow-up was at 6, 12, and 26 weeks. RESULTS: A moderate correlation between intraprostatic temperatures and energy output (r = 0.409; P < or = 0.046) and prostate volume (r = 0.303; P < or = 0.0424) was observed. Outlet obstruction was associated with higher temperatures (obstructed 49.6+/-5.8 v unobstructed 46.1+/-4.2 degrees C; P < or = 0.033). A significant relation between temperature and clinical outcome was found. Patients with intraprostatic temperatures <46 degrees, 46-50 degrees, and < or = 50 degrees C had significant differences in Madsen score change (-50%, -68% and -86%) and in maximum flow rate (+26%, +32%, and +48%). Patients with temperatures >50 degrees C had a significant improvement in obstruction status (86% to 18%). A slight worsening in voiding dynamics was observed in patients with temperatures <50 degrees C. CONCLUSION: A significant relation exists between intraprostatic temperatures achieved during TUMT and the clinical outcome. Temperatures in excess of 50 degrees C seem to be associated with a greater improvement in lower urinary tract symptoms and bladder outlet obstruction. These data provide a sound rationale for monitoring intraprostatic temperatures and developing invasive thermometry feedback mechanisms for thermal treatments of BPH.

Aged↗
PubMed2000

Invasive and minimally invasive treatment modalities for lower urinary tract symptoms: what are the relevant differences in randomised controlled trials?

OBJECTIVES: This manuscript reviews the outcomes of invasive and minimally-invasive treatments of lower urinary tract symptoms due to prostatic enlargement. METHODS: The MEDLINE database was searched for Medical Subject headings and text words including prostatic hyperplasia, treatment, surgery, thermal treatments, thermotherapy, laser, TUNA and vaportrode. Data from both randomised and non-randomised controlled trials were considered. RESULTS: All invasive treatments produce significant changes of all subjective and objective outcome parameters. The best clinical outcome has been reported for open prostatectomy followed by transurethral resection of the prostate. Complications of the different invasive techniques were difficult to analyse because of the heterogeneity of categories among different papers and lack of standard criteria. The major attraction of all minimally invasive treatment options is the low risk of bleeding requiring blood transfusions. Retrograde ejaculation was one of the most frequently reported complications for all invasive techniques. Some of the so-called less invasive treatment options appeared to be associated with a rather high incidence of minor complications somehow contradicting their minimally invasiveness. Re-treatment rate observed in patients receiving various minimally invasive treatments was always higher than following standard treatment options such as transurethral resection. CONCLUSIONS: Open prostatectomy and transurethral resection of the prostate outperform all minimally invasive treatment modalities as regards efficacy and durability of outcome. The lack of standard criteria to evaluate complications and side effects makes treatment comparisons difficult. Endorsement of the clinical research criteria proposed by the last WHO-sponsored International Consultation on BPH is strongly recommended to improve the clinical value of randomised and non-randomised controlled trials. More information is needed on long-term complications and cost-effectiveness of minimally invasive treatment modalities.

Humans↗
PubMed1999

Fluorometric analysis of pectenotoxin-2 in microalgal samples by high performance liquid chromatography.

A rapid HPLC method with fluorescence detection of pectenotoxin-2 (PTX2), a polyether macrolide toxin, in microalgae is presented. A dienophile reagent, DMEQ-TAD, was used for precolumn fluorescence labeling. PTX2 could be quantitatively detected in the range 1-200 ng. This method confirmed the occurrence of PTX2 in net haul samples mostly composed of dinoflagellates Dinophysisspp. collected in the Adriatic Sea, Italy and Mutsu Bay, Japan.

Animals↗
PubMed1999

Methodological improvement of the protein phosphatase inhibition assay for the detection of okadaic acid in mussels.

A simplified procedure for the enzyme inhibition assay to measure okadaic acid and DTX-1 in mussels, based on the use of a commercially available enzyme preparation, is presented. The detection limit is 10 ng of toxin per g of digestive glands. Using Certified Reference Material (MUS-2), high accuracy and good precision is demonstrated for contamination levels higher than 32 ng g(-1). Twenty samples can be processed in about 9 h by one operator, at the cost of US$ 10 per sample. Some possibilities for further enhancing the sensitivity and reducing the processing time are discussed and a monitoring example is presented.

Animals↗
PubMed1999

The use of voiding studies (flowmetry and urodynamics) in the assessment and follow-up of patients.

The role of urinary flow measurement and pressure-flow studies in the diagnostic work-up of men presenting with lower urinary tract symptoms suggestive of benign prostatic obstruction is still an unresolved issue. In this paper, evidence from the peer-reviewed literature of the last 12 months is critically reviewed in the light of the recent recommendations of the 4th International Consultation on benign prostatic hyperplasia.

Diagnostic Techniques, Urological↗
PubMed1999

Management of symptomatic BPH in Italy: who is treated and how?

OBJECTIVE: To investigate the management of symptomatic benign prostatic hyperplasia (BPH) in Italy. METHODS: Information on diagnosis, medical and surgical treatment was obtained from two different questionnaires independently mailed to urological centers in Italy. Data on drug treatments were obtained from a national database. General practitioner (GP) clinical practice patterns were obtained from a panel discussion between general practitioners and urologists. RESULTS: First line medical treatment is currently undertaken by GPs more often and to a smaller extent by urologists to whom patients can self-refer. Primary care diagnostic algorithm consists of patient's interview, physical rectal examination and urinalysis. The main reason for referral of a BPH patient to the urologist by GPs appears to be an unsatisfactory outcome of first line medical therapy. Examination of the suprapubic area plus rectal examination is always performed by urologists during physical examination while evaluation of motor and sensory function is carried out in 28% of patients only. Voiding diary and I-PSS score are currently used by 17 and 65% of urologists, respectively. Urinalysis, plasma creatinine and prostate specific antigen (PSA) are used in 100, 94 and 89% of cases, respectively. Ninety-four percent of urologists use uroflowmetry with evaluation of post voiding residual by ultrasound. Pressure-flow studies are used in selected cases by 89% of urologists. Ultrasound imaging of the kidney, bladder and prostate transrectal ultrasound (TRUS) is reported as current practice in 79, 71 and 53% of questionnaires, respectively. Over six million medical consultations with prescriptions for BPH were carried out in 1998 accounting for 190, 600,000 drug treatment days. Prescriptions for 5alpha-reductase inhibitors accounted for 71,400,000 days of treatment, alpha-blockers for 104,000,000 and plant extracts for 15,300,000 days. In 24 to 28% of cases more than one drug was prescribed. Indications for invasive treatment rely on symptoms (98%), presence of BPH complications (90%), flowmetry (65%), residual urine (50%), prostate volume (40%) and urodynamics (20%). About 10% of patients consulting the outpatient clinics were allocated to watchful waiting, 50% received pharmacological treatment and 40% invasive treatment. Analysis of invasive treatment options resulted in 62% of patients receiving transurethral resection of the prostate (TURP), 29% open prostatectomy and the remaining 9% received various forms of minimally invasive treatments. Patients were most commonly followed up for 3 months with 62% of patients followed up at one year post-operatively and then yearly. CONCLUSIONS: Our survey suggests that the current clinical practice of primary and secondary care physicians is in line with the recommendations of the IVth International Consultation on BPH. However, Italian urologists seem to use less frequently symptom scores and voiding diaries than recommended. It seems that open surgery is more frequently used in Italy than in other European countries. Minimally invasive treatments remain a very small portion of interventions for the management of BPH in Italy. Fifty-five percent of patient days of treatment are alpha-blockers, 37% is finasteride. The share of alpha-blockers has dramatically grown with the introduction of the first prostate-selective agent, tamsulosin. Copyrightz1999S.KargerAG, Basel

Forecasting↗
PubMed1998

Analysis of outcome after thermotherapy using different classifications of bladder outlet obstruction.

The urodynamic profiles of 97 patients with benign prostatic hyperplasia undergoing low-energy transurethral microwave thermotherapy (TUMT) for lower urinary tract symptoms were analysed using the Abrams/Griffiths nomogram, the urethral resistance algorithm, the linPURR, Schäfer nomogram, and the CHESS classification. A significant clinical response was seen for the whole group, as shown by changes in symptom score, free flow rate, and residual urine. The best symptomatic response was identified in patients in whom obstruction was present, whatever the classification used. Only the two-dimensional CHESS classification was found to predict a group of patients with a better response in both symptoms and objective variables. Obviously, a better response from TUMT can only be predicted by a classification system that identifies the independent variables of footpoint and slope of the PURR. The CHESS classification was the only one of those studied that satisfactorily identified these two parameters and could be used as a system of case selection for this minimally invasive treatment.

Aged↗
PubMed1998

Case selection for high-energy transurethral microwave thermotherapy.

Transurethral microwave thermotherapy (TUMT) is a minimally invasive outpatient procedure for the treatment of benign prostatic hyperplasia (BPH). Different devices and operating software have been used in various clinical trials. The objective of this study was to identify the possible baseline parameters that could be used to identify the best responders to different microwave devices and treatment programs. Data on three different high-energy thermotherapy devices (Urowave, Prostalund, and Prostatron) were collected and analyzed. At 1 year of follow-up, 166 patients were available for the Prostatron system. In all, 52 had a > or = 50% change in both symptom score and peak flow rate, whereas 114 patients were considered nonresponders. Responders were characterized at baseline by a lower peak flow rate (8.80 versus 10.48 ml/s, P < or = 0.0001) and a larger degree of outlet obstruction as measured by the URA parameter (45.33 versus 36.70 cmH2O, P < or = 0.0300); a larger energy dose was delivered to this group during treatment (173.36 versus 156.40 kJ, P < or = 0.0258). A total of 19 patients were available from the Prostalund cohort. No significant difference was found in the values recorded for baseline parameters between responders (5 patients) and nonresponders (14 patients). Stratification of 143 patients treated with the Urowave resulted in 29 responders (> or = 50% improvement in both Qmax and AUA score) at 6 months of follow-up, with a significant difference being found in the baseline value recorded for peak flow rate (7.0 versus 8.0 ml/s, P < or = 0.026). At 12 months, however, this significance difference could no longer be found. In conclusion, baseline parameters with significant predictive value for a clinical response could be identified for the Prostatron device only. The results of this study further confirm the importance of an extensive laboratory and clinical research program for a fuller understanding of the clinical response obtained with a certain microwave device and a particular treatment software and for provision of the greatest possible advantage from these new alternative treatments. Further exploratory work is required for a better understanding of the role of other parameters such as prostate tissue architecture and vascularity, the microwave frequency, the applicator design, the intraprostatic temperature, and the treatment duration in the clinical response to microwave thermotherapy.

Diathermy↗
PubMed1998

The diagnosis of bladder outlet obstruction in men by ultrasound measurement of bladder wall thickness.

PURPOSE: The objective of the study was to investigate specificity and sensitivity of bladder wall thickness in the diagnosis of bladder outlet obstruction. MATERIALS AND METHODS: The study included 174 patients referred to our prostate centers for lower urinary tract symptoms. Free uroflowmetry and pressure-flow studies were performed in duplicate as part of the diagnostic evaluation. After the 2 voiding studies were done the bladder was filled to 150 ml. and wall thickness was measured via suprapubic ultrasound. Bladder outlet obstruction was diagnosed and graded according to the Abrams-Griffiths and Schäfer nomogram as well as to the group specific urethral resistance algorithm. RESULTS: A significant correlation (r > 0.6, p < or = 0.007) was found between bladder wall thickness and all parameters of the pressure-flow study. A bladder wall thickness of 5 mm. appeared to be the best cutoff point to diagnose bladder outlet obstruction, since 63.3% of patients with bladder wall thickness less than 5 mm. were unobstructed while 87.5% of those with a bladder wall thickness 5 mm. or greater were obstructed. Bladder wall thickness out performed uroflowmetry in terms of specificity and sensitivity in the diagnosis of outlet obstruction as demonstrated by an area under curve value of 0.860 versus 0.688 in the receiver operator characteristics analysis. CONCLUSIONS: Measurement of bladder wall thickness appears to be a useful predictor of outlet obstruction with a diagnostic value exceeding free uroflowmetry although it does not represent a substitution to invasive urodynamics. These data support the hypothesis that the relationships between morphology and function are of clinical importance.

Adult↗
PubMed1998

[International prostate symptom score: comparison of doctor and patient].

The AUA 7 score was originally designed and validated to be self administrated to patients with LUTS, its subsequent endorsement by the WHO - BPH committee made it the most widely used. Translation into different was provided and sometime validated. Aim of the study was to investigate the possibility to self administer the IPSS questionnaire to patients referred to our Institution for lower urinary tract symptoms. Two hundred and thirty-tree consecutive patients were given the IPSS questionnaire as a part of the routine diagnostic schedule; a senior resident was available to answer any possible question from the patient. After the form was returned, a second IPSS questionnaire was filled in by investigator following patient interview. Data were entered into an Excel database and the following parameters were investigate: number of forms completely filled in by patient, number of question answered in incomplete forms, degree of concordance between patient and investigator. One hundred and fifteen patients were able to fill the AUA 7 form completely; the quality of life question was answered by ninety-six patients only. Comparison of individual scores provided by the patient or assigned by the investigator showed a trend for the physician to underscore the patient problem for question 1-4 and to overestimate it in questions 5 to 7. At the lower range of the IPS score (0-7) no significant different between physician and patient was found. In the intermediate range (8-19) the physician tended to overestimate the patient symptoms. The reverse situations was found in the high score range (20-35). Globally, there was a trend for the patient score to be higher than the one assigned by the investigator, Doctor IPSS and quality of life scores appeared to be significantly related. No relation was found between doctor IPSS and the degree of bladder outlet obstruction as measured by parameter of pressure-flow study and diagnostic nomograms. The IPSS form appeared to be a difficult questionnaire for our patients and less than half of them were able to fill it in properly. Overall, the investigators tended to underestimate the patient voiding disturbances. Careful linguistic review of the Italian version of the IPSS questionnaire is required to make self evaluation of patient symptom possible. Symptom grading by a trained investigator did not seem to introduce any significant bias which might be of importance for the sake of clinical trials.

Adult↗
PubMed1998

[The Studer orthotopic ileal neobladder: patient compliance].

Radical cystectomy represents the gold standard for locally advanced bladder cancer. Orthotopic neobladder is considered the surgical option which may offer the least modification of body image and the best life condition to the unfortunate patient requiring radical cystectomy. Objective of this study was to investigate long term clinical outcome of orthotopic ileal bladder substitute with special reference to late complications and patient compliance. Twenty male patients 48 to 71 years old (mean age 59.8 + 7.4 years) underwent radical cystectomy and Studer orthotopic ileal neobladder for invasive carcinoma of the bladder. Before surgery all patients filled in a phycometric test for evaluating their knowledge capacity; after surgery they underwent a course of biofeedback and instructed to avoid overfilling of the neobladder with timed micturitions and a regular regimen of fluid intake. Pressure flow study was included in the routine follow-up carried out at six months and then yearly. Seventeen patients (85%), with a good knowledge capacity, reported a good compliance to the modified life style imposed by the bladder substitute, they all were dry during the day with 3 to 5.5 hour interval between micturitions; fourteen of these patients were continent at night with timed micturitions every 3-4 hours (mean: 3.2); an average cystometric capacity of 450 ml was found in these patients with no residual urine; three patients (18%) had incontinence episodes once or twice a week during the night; no decompensation of the neobladder, significant ureteral reflux or dilatation were reported; elongation of the afferent loop was found in one patient following small bowel resection for ileal volvulus. Three patients (15%), with a reduced knowledge capacity, who did not follow the suggested life style: fluid intake was irregular, micturitions were not timed during both day and night time, had residual urine larger than 400 ml. and incontinence episodes requiring pads; nevertheless no dilation of the upper urinary tract was found. Our experience suggests that careful compliance of patients to the new life style imposed by the orthotopic neobladder is of importance to avoid its decompensation. The possible causative role of gastrointestinal hormones such as enteroglucagon (EG) and peptide tyrosine-tyrosine (PYY) in the elongation of the afferent limb of the Studer neobladder is proposed. In conclusion, we believe that orthotopic ileal neobladder is an ideal surgical option on in the young, educated and cooperative patients.

Aged↗
PubMed1997

Anti-oedematous activities of the main triterpendiol esters of marigold (Calendula officinalis L.).

Separation and isolation of the genuine faradiol esters (1, 2) from flower heads of Marigold (Calendula (officinalis L., Asteraceae) could be achieved by means of repeated column chromatography (CC) and HPLC for the first time. Structure elucidation of faradiol-3-myristic acid ester 1, faradiol-3-palmitic acid ester 2 and psi-taraxasterol 3 has been also performed, without any previous degradation by means of MS, 1H-NMR, 13C-NMR and 2D-NMR experiments. The anti-oedematous activities of these three compounds were tested by means of inhibition of Croton oil-induced oedema of the mouse ear. Both faradiol esters showed nearly the same dose dependent anti-oedematous activity and no significant synergism appeared with their mixture. The free monol, psi-taraxasterol, had a slightly lower effect. Furthermore, faradiol was more active than its esters and than psi-taraxasterol and showed the same effect as an equimolar dose of indomethacin.

Animals↗
PubMed1997

Manual versus computer methods for diagnosing obstruction from pressure-flow tracings in patients with benign prostatic hyperplasia.

PURPOSE: We compared manual versus computer analysis of pressure-flow tracings for diagnosing bladder outlet obstruction in patients with benign prostatic hyperplasia. MATERIALS AND METHODS: A total of 105 patients with a clinical diagnosis of prostate enlargement and lower urinary tract symptoms was included in the study irrespective of free flow rates. Pressure-flow studies were performed in duplicate and tracings were evaluated by 2 independent investigators blinded to patients status. Manual reading of urodynamic printouts and fully computerized analysis using CLIM software were done. All urodynamic parameters relevant to the diagnosis of outlet obstruction were compared using the Abrams-Griffiths and Schäfer nomograms. Group specific urethral resistance factors were also compared. RESULTS: There was good correlation between manual and computer derived values of maximum flow (r = 0.9874, p < or = 0.0001), detrusor pressure at maximum flow (r = 0.9943, p < or = 0.0001), minimum detrusor pressure during voiding (r = 0.8816, p < or = 0.0001) and group specific urethral resistance factor (r = 0.9917, p < or = 0.0001). The diagnosis of outlet obstruction according to the group specific urethral resistance factor, and the Abrams-Griffiths and Schäfer nomograms was highly consistent using the manual and computerized approaches. CONCLUSIONS: Manual analysis of pressure-flow tracings generated by urodynamic equipment and digital data obtained by CLIM software appeared to be highly consistent and equally reliable for diagnosing and grading outlet obstruction.

Aged↗
PubMed1996

A protein phosphatase 2A inhibition assay for a fast and sensitive assessment of okadaic acid contamination in mussels.

The specific inhibitory activity exerted by okadaic acid on protein phosphatase 2A was used to assess the presence of okadaic acid in mussels, using a commercially available protein phosphatase 2A preparation. Under the conditions used, okadaic acid inhibits the enzymatic activity dose-dependently, with an IC50 = 0.26 ng/ml (0.32 nM). The assay is accurate and reproducible. Okadaic acid was detected in concentrations as low as 0.063 ng/ml in aqueous solutions and 2 ng/g in mussel digestive glands. Thirty naturally contaminated mussel samples were submitted to the protein phosphatase 2A inhibition assay as well as to an ELISA assay and to a MTT cytotoxicity assay, with similar results. The proposed assay is sensitive, rapid and does not require expensive equipment. These characteristics make it a good candidate for employment in the routine assessment of okadaic acid shellfish contamination.

Animals↗
PubMed1996

Suitability of the MTT-based cytotoxicity assay to detect okadaic acid contamination of mussels.

The suitability of a cytotoxicity assay based on the MTT colorimetric method has been evaluated for the detection of okadaic acid in mussels. On KB cells, okadaic acid exhibited a dose-dependent cytotoxic effect, the IC50 being inversely related to the exposure time (IC50 = 6.3 ng/ml, 4.0 ng/ml and 1.1 ng/ml after 24, 48 and 72 hr of contact, respectively). Using a contact time of 24 hr, the MTT cytotoxicity assay is suitable for revealing okadaic acid concentrations in mussel samples as low as 50 ng/g of digestive glands, with a sensitivity higher than that of the commercially available kits for enzyme-linked immunosorbent assay (ELISA). In the okadaic acid concentration range from 50 to 1500 ng/g of digestive glands the MTT cytotoxicity assay showed satisfactory accuracy and reproducibility. A high degree of correlation was found between the okadaic acid content of 16 naturally contaminated samples measured by the MTT cytotoxicity assay and by an ELISA.

Animals↗