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Biomedical subjects

A Tasca

Publications and source records attributed to A Tasca.

At least 19 recordsLinked to original sources
PubMed2004

Plasma bubble formation induced by holmium laser: an in vitro study.

OBJECTIVES: To use the elementary physical measurements of temperature and size to prove that the thermal effects produced by the holmium laser's pulses are due to the formation of a plasma bubble. The physical phenomenon related to high temperatures generated during procedures with the holmium laser (holmium:yttrium-aluminum-garnet) was the object of our interest. METHODS: Using a double micrometric slide attached to a 550-microm optic fiber and two thermocouples submerged in water, a series of pulses of 0.8 J at 10 to 30 Hz was delivered from a holmium:yttrium-aluminum-garnet laser, and we recorded temperatures on both frontal and lateral planes. Subsequently, samples of prostatic tissue and small stones were treated with 1.5 J at 20 Hz on both frontal and lateral planes. RESULTS: Treatment with 1.5 J at 30 Hz (frontal plane) and with 1.5 J at 20 Hz (lateral plane) produced the ablation of the structure of the thermocouple at 2 mm and 1 mm, respectively, indicating plasma formation. The dimensions of the bubble after the delivery of 1.5 J at 20 Hz was 2 x 1.5 mm. Coagulation of the prostatic tissue took place at 1 mm from the plasma bubble, on both frontal and lateral planes. CONCLUSIONS: The plasma bubble that forms at the tip of the fiber connected to the holmium:yttrium-aluminum-garnet laser makes it possible to work on stones and soft tissues. The coagulation of the prostatic tissue is caused by the hot water-vapor bubble that forms on the edge of the plasma bubble. During lithotripsy, guidewires and baskets within the expansion area of the plasma bubble risk damage.

Aluminum↗
PubMed2004

Mini-invasive management of a rare complication of percutaneous stone treatment: entrapped nephrostomy tube.

A case of entrapped nephrostomy tube in a 61-year-old woman who underwent percutaneous nephrolithotomy and subsequent multiple ESWL for a left staghorn stone is presented. A nephrostomy track was created alongside the Malecot catheter and the overgrown tissue which was bridging the wings of the tube was incised with a Sachse urethrotome. To prevent this complication the wings of the Malecot should freely expand in the renal collecting system and the catheter should stay in situ for no more than 3 weeks.

Equipment Failure↗
PubMed2003

Experience with an elective vacuum assisted cardiopulmonary bypass in the surgical treatment of renal neoplasms extending into the right atrium.

PURPOSE: We evaluate the results of an elective cardiopulmonary bypass conceived to minimize the surgical risk related to its use with temporary circulatory arrest and deep hypothermia in the treatment of patients with renal tumor extending into the right atrium. MATERIALS AND METHODS: From July 1996 to December 2000, 19 patients with renal neoplasm and venous involvement were admitted to our department. Three patients 4, 57 and 58 years old with a right (2) and left (1) renal tumor extending into the right atrium underwent radical nephrectomy and tumor thrombus removal using a normothermic cardiopulmonary bypass. The bypass circuit was connected with a vacuum assisted venous drainage giving a negative pressure of 20 to 40 mm. Hg. Neither circulatory arrest nor hypothermia was used. Tumor thrombus was extracted through a longitudinal "cavotomy" and removed along with the kidney. RESULTS: Total cardiopulmonary bypass time was 14, 19 and 22 minutes, respectively. No intraoperative or postoperative complications due to surgical technique occurred. No significant bleeding was observed at the time of cavotomy and all neoplastic tissue was removed. Pathological examination documented renal cell carcinoma in 2 cases and Wilms tumor in 1. All the patients are alive 30, 42 and 15 months, respectively, after the operation. CONCLUSIONS: Normothermic cardiopulmonary bypass with vacuum assisted venous drainage makes circulatory arrest and hypothermia unnecessary and avoids the potential complications associated with these procedures. With respect to veno-venous shunts this technique guarantees complete surgical control of the thrombus and avoids the need for extensive dissection of the retrohepatic vena cava and Pringle maneuver.

Cardiopulmonary Bypass↗
PubMed2003

High-energy microwave thermotherapy in the treatment of benign prostatic hyperplasia.

INTRODUCTION: Transurethral microwave thermotherapy is an anesthesia-free, outpatient method of treating lower urinary tract symptoms due to benign prostatic hyperplasia (BPH). Our results with the use of this technique in 25 patients are reported. MATERIALS AND METHODS: Twenty-five patients with BPH, 8 of whom with complete urinary retention, were treated with high-energy transurethral microwave thermotherapy (HE-TUMT) (Prostatron system). Preoperative investigations included digital rectal examination, urinary free flow rate, PSA, urinalysis, urine culture, transrectal ultrasonography, urodynamic evaluation, International Prostatic Symptom Score (IPSS) and quality of life (QoL). Main selection criteria included: large prostate, high surgical risk, reluctance to undergo surgery. All patients were obstructed according to the Abrams-Griffith's nomogram. For the statistical analysis a repeated-measures, one-way ANOVA was performed on previously non-catheterized patients. RESULTS: Six of the 8 patients with catheter before treatment were able to urinate spontaneously with no significant post-voiding residual urine. In the 17 remaining patients, IPSS decreased from a mean of 18.5 at baseline to 7.30 and QoL from a mean of 3.9 to 1.2. Mean maximum flow rates during uroflowmetry increased from 8.5 to 16.9 ml/s. P(det) Q(max) decreased from a mean of 83.0 cm H(2)O at baseline to 50.7 cm H(2)O and Q(max) increased from a mean of 6.8 ml/s at baseline to 15.1 ml/s during the pressure-flow study. After TUMT, 13 patients were unobstructed and 4 equivocal according to the Abrams-Griffith's nomogram. CONCLUSION: Our study performed in a selected population of patients with BPH documents the efficiency and safety of HE-TUMT. This technique appears to be a valid therapeutic option, particularly in patients with high surgical risk.

Aged↗
PubMed2002

Bone alterations in patients with idiopathic hypercalciuria and calcium nephrolithiasis.

OBJECTIVES: To verify whether alterations in bone density and turnover in patients with calcium nephrolithiasis and hypercalciuria are observable in various subgroups of patients divided according to the pathogenesis of the hypercalciuria. METHODS: Seventy patients with calcium nephrolithiasis and idiopathic hypercalciuria, 19 to 64 years old, were assessed for spine and femur mineral metabolism and bone density using a Dexa evaluation system. After a low calcium diet, the subjects were classified into two groups: fasting hypercalciuria (FH, 39 patients) and absorptive hypercalciuria (AH, 31 patients). RESULTS: Only in the patients with FH was the lumbar spine bone density lower than in the controls (P <0.001). Also, only the patients with FH had higher bone alkaline phosphatase and urinary hydroxyproline levels than the control group (P <0.005 and <0.015, respectively). The blood pH levels were lower, even though within the normal range, in the hypercalciuric patients than in the controls (P <0.01). There was a negative correlation between the urinary hydroxyproline level and lumbar spine and femoral neck density in patients with FH (P <0.001 and <0.005, respectively), and the blood pH correlated positively with the lumbar spine bone density. CONCLUSIONS: Altered bone metabolism and overall bone loss were found only in the patients with FH. Overloading of acid valences, perhaps of dietary origin, could be the pathogenic factor responsible.

Adult↗
PubMed2001

Bulbar urethral stricture repair with buccal mucosa graft urethroplasty.

OBJECTIVES: Evaluation of the use of buccal mucosa graft as single-stage urethral reconstruction in an adult population with a stenosis of the bulbar urethra. METHODS: In our Department between April 1996 and February 1999, 20 patients with bulbar urethra stenosis underwent single-stage urethroplasty using a buccal mucosa graft. Mean age of patients was 52 years (range 14-70). The etiology of urethral stricture was inflammation (4 cases), iatrogenic (5 cases) and idiopathic (11 cases). A ventral onlay patch (mean length 3.6 cm, range 2.5-5) was employed in all cases. RESULTS: During the follow-up (median 13 months, range 6-28) the overall success rate was 80%. The success rate was 75% for inflammatory strictures, 80% for iatrogenic strictures and 81% for strictures of unknown etiology. CONCLUSIONS: Although longer follow-up is needed, free graft urethroplasty with buccal mucosa graft represents a simple surgical option which has produced encouraging results. This is probably due to the quality of the tissue employed which at present seems to represent the first-choice solution in selected cases.

Adolescent↗
PubMed1998

Bone density and skeletal metabolism are altered in idiopathic hypercalciuria.

OBJECTIVE: To study bone density in hypercalciuric patients, when classified according to the main metabolic defect. METHODS: We studied 49 patients, aged 19-60 years with calcium stones and idiopathic hypercalcuria. All subjects underwent an evaluation of mineral metabolism and a spinal and femoral DEXA measurement. Then, patients were classified as having Fasting (FH, 31 subjects) or Absorptive (AH, 18 patients) Hypercalciuria according to a standard oral calcium load. RESULTS: Spinal bone density was lower only in FH patients as compared to controls (p <0.001). Bone alkaline phosphatase and urine hydroxyproline were higher with respect to controls only in patients with FH (p <0.005 and p <0.015, respectively). After low calcium diet, hydroxyproline excretion continued to be higher in FH patients (p <0.05). Although in the normal range, serum and urine uric acid were higher in hypercalciuric subjects (p <0.03 and p <0.005, respectively); blood pH was lower in hypercalciuric patients than in controls (p <0.01). In FH patients urine hydroxyproline negatively correlated with spinal and femoral density (p <0.001 and p <0.005, respectively), and blood pH positively correlated with spinal density. CONCLUSIONS: a disordered bone metabolism and bone loss are present only in patients with fasting hypercalciuria. An excessive acid load, possibly of dietary origin, might be involved as a pathogenetic factor.

Absorptiometry, Photon↗
PubMed1995

Transurethral laser surgery with a conventional modified resectoscope.

A new 1,800-microns side fiber made of pure silica with laser beam deviation of 82 degrees and divergence of 18 degrees was inserted into a modified transurethral resectoscope and used to treat in vitro some prostates removed during radical prostatectomy. Sterilization of prostatic tissue with a depth of penetration of 12 mm was observed after treatment with 20 W for 2 min. Irradiation with 60 W for 1 min produced vaporization and explosion of the tissue and a depth of penetration of 15 mm. The laser resectoscope was then successfully employed for the treatment of 6 cases of benign prostatic hyperplasia (BPH) as well as in high risk patients with bulky bleeding bladder tumors (4 cases) and with transitional carcinoma of the prostate invading the parenchyma (2 cases). 3 patients with small size BPH underwent only laser irradiation. All others were submitted to traditional transurethral resection followed by laser treatment with Nd: YAG using the same instrument. Our laser resectoscope lowers costs since the side fiber is reusable for 4-5 treatments and brings laser treatment nearer to traditional endoscopic treatment, thereby making its application more comfortable for the urologist.

Cystoscopy↗
PubMed1993

Photosensitization of cystine stones to induce laser lithotripsy.

We report the preliminary results of laser lithotripsy of cystine stones accomplished in 2 patients with the use of a new method of photosensitization. Transurethral rigid ureterorenoscopy was performed with an 8.5F instrument to reach 0.8 and 1.8 cm. stones located in the right and left lumbar ureters, respectively. A 320 mu. fiber was then inserted and pushed into contact with the stone. Then, 400 preliminary impulses were released from a pulsed dye laser (504 nm) with energy output at 140 mJ. and at a rate of 5 Hz. without any visible modification of the stone structure. The saline solution used as irrigation fluid was then substituted with a 2% solution of rifamycin. Totals of 95 and 152 impulses released at the same energy output previously used were then sufficient to produce a satisfactory fragmentation of the stone in both cases. Sonography and excretory urography showed no alterations of the treated urinary tract in either case. The use of rifamycin in the irrigation fluid is suggested for laser treatment of hard or nonabsorbent stones, since this substance favors optical coupling and lowers the threshold of plasma formation on the surface of the stone.

Adolescent↗
PubMed1993

Possible link between vitamin D and hyperoxaluria in patients with renal stone disease.

1. Vitamin D seems to play an essential role in the pathogenesis of idiopathic hypercalciuria at least in part via intestinal hyperabsorption of calcium. Hyperabsorption of calcium, in turn, might enhance the intestinal uptake of free oxalate, thus leading to hyperoxaluria. To verify this hypothesis we studied 75 calcium-stone-formers subdivided as follows: group 1 (15 patients) with isolated hyperoxaluria; group 2 (25 patients) with hyperoxaluria and hypercalciuria; group 3 (22 patients) with isolated hypercalciuria; group 4 (12 patients) with no metabolic abnormalities. 2. As expected, urinary calcium excretion differed in the various groups (P < 0.001), being highest in groups 2 and 3; urinary oxalate excretion, by definition highest in groups 1 and 2, was even more pronounced in group 2 than in group 1 (P < 0.05). Although in the normal range, the serum 1,25-dihydroxyvitamin D concentration was higher (P < 0.001) in the two hypercalciuric groups (2 and 3), showing peak levels in group 2. 3. When the data from the 75 stone-formers were pooled, there was a positive correlation between the serum concentration of 1,25-dihydroxyvitamin D and urinary calcium excretion (P < 0.001) and urinary oxalate excretion (P < 0.003), the latter relationship also being present when only the two hypercalciuric groups (groups 2 and 3) were considered together (P < 0.05). 4. Our data seem to confirm a relevant role for the vitamin D system in the pathogenesis of calcium nephrolithiasis due to increased intestinal calcium absorption, but also because this in turn induces a greater intestinal absorption of oxalate, thus leading to the occurrence or exacerbation of hyperoxaluria.

Adult↗
PubMed1993

Five years experience in experimental laser lithotripsy.

In the first part of our experience approximately 300 stones of different composition have been treated in vitro with three different laser sources: Nd-YAG laser (1,064 nm), dye laser (504 nm) and alexandrite laser (755 nm). Calcium oxalate monohydrate and brushite stones appeared to be the most resistant to lithotripsy. Highest fragmentation rates were obtained for calcium oxalate dihydrate stones followed by struvite, uric acid and hydroxyapatite stones. The Nd-YAG laser did not appear to be ideal for lithotripsy since early damage to the fiber tip was observed when this source was used. Both the dye and the alexandrite lasers were almost always effective in fragmenting the various types of stones. We subsequently treated some cystine stones while immersed in water or in solutions of carmine indigo (2%), methylene blue (5%), rifamycin (0.6 and 6%) and rifampicin (0.8 and 0.3%) with the dye or the alexandrite laser. The spectra of these solutions, previously analyzed with the spectrophotometer, showed that rifamycin and rifampicin absorbed large amounts of light radiation at the wave length of the dye laser (504 nm). Successful fragmentation occurred only when the dye laser was used to treat stones immersed in the more concentrated solutions of these two substances. The quantity of fragmented material after treating a 10-cm3 cystine stone previously immersed in the more concentrated solutions of rifamycin and rifampicin (30 and 10 mm3, respectively) confirmed previous results.(ABSTRACT TRUNCATED AT 250 WORDS)

Humans↗
PubMed1991

[Endourological treatment of ureteral stenoses].

Conservative treatment of ureteral stenoses has been possible since the evolution in materials and methods available. We report our experience in 49 cases of ureteral stenoses (1 case with bilateral lesion). The etiology was as follows: 3 cases of tuberculous strictures, 10 late complications of endourological treatment of ureteral stones, 16 stenoses of ureteroenteric anastomoses or bladder reimplantation, 16 after radical pelvic surgery, 5 after external beam radiation therapy. Forty-two cases were treated with balloon dilation or by means of a coaxial dilator; in 7 cases a cold-knife treatment was performed. All patients had a ureteral stent for 40 days. The results were evaluated by IVP, sonography and DTPA renal scan, 6 to 20 months after stent removal. Overall success rate was 56%: it was lower than the 100% rate obtained in a 13 patients group surgically treated. In selected cases of ureteral stenoses, endourological approach should be the first choice treatment because of low morbidity and reduced hospitalization time.

Adolescent↗
PubMed1990

The case for a percutaneous approach to transitional cell carcinoma of the renal pelvis.

Percutaneous treatment of transitional cell carcinoma of the renal pelvis in 4 patients is reported. The presenting symptom was hematuria in 2 patients, while in 2 diagnosis was made by chance at excretory urography. Endoscopic removal of the tumor was not possible in the 2 patients who underwent transurethral ureteroscopy due to the location of the lesion. Percutaneous electroresection of the tumor was performed after puncture of an inferior (3 patients) or middle (1) calix and dilation of the nephrostomy tract up to 30F. Pathological findings revealed a grade 1 papillary carcinoma in 3 patients and a well differentiated inverted papilloma in 1. A single-J ureteral catheter was left in place after the procedure. Cytological, radiographic and endoscopic studies were negative 11, 13, 18 and 24 months after the treatment, respectively. We believe that the percutaneous approach is a feasible option in cases of small, single, low grade lesions not removable via ureteroscopy, particularly in patients at high surgical risk.

Aged↗
PubMed1990

[Endo-urology in diseases of the upper urinary tract other than tumors and calculi].

Thirty-three patients underwent percutaneous treatment for upper urinary obstructive disease in our Institute. Cold-knife incision of 16 cases of uretero-pelvic junction obstruction and 4 cases of infundibular stenosis was performed. Balloon dilatation of the caliceal neck was performed in 1 patient with caliceal diverticulum. In 4 of the patients treatment failed requiring open surgical correction. Thirteen patients presented iatrogenic ureteral obstruction: balloon dilatations or cold-knife incisions were performed. Four of the 9 patients evaluable obtained significant benefit from the endourological treatment. Endopyelotomies for UPJ obstruction seem effective and reduce morbidity and operating times. Ureteral obstructions appear less responsive to the endo-urological approach. Definitive conclusions concerning the effectiveness of these procedures requires larger series of patients and longer follow-up.

Adolescent↗
PubMed1989

Pediatric nephroscope for percutaneous renal stone removal.

A new 17-F nephroscope was used for percutaneous renal stone management. It appeared useful in reducing the possible main vascular injuries after percutaneous nephrolithotomy. Personal experience with pediatric as well as selected adult cases is presented.

Adolescent↗
PubMed1988

Short-term and stabilized effects of percutaneous nephrolithotomy on the kidney.

A homogeneous group of 15 patients was investigated before and after percutaneous nephrolithotomy (PCN). Creatinine and electrolyte clearances evaluated both before and during saline (NaCl 0.9%) infusion, 4-7 days after PCN remained unchanged with respect to the preoperative values. A significant decrease of urinary PGE2 was observed postoperatively both before and after extracellular volume expansion. 99mTc-DTPA renography performed 26-40 days after surgery showed a scar on the convex margin of one kidney in the area of the nephrostomy and an improved renographic curve in 5 renal units. No difference between pre- and post-PCN isotopic clearances was evident. On the basis of our results we can affirm that PCN is an efficient and safe method for the treatment of nephrolithiasis.

Adult↗