Biomedical subjects
Publications and source records attributed to C Saussine.
A 61-year old man presented with a subcapsular renal hematoma following Extracorporeal Shock Wave Lithotripsy for a renal stone. The authors discuss presenting conditions, risk factors, preventive measures, therapeutic implications and sequellae of such a complication.
Studies were conducted to test whether parathyroid hormone-related protein (PTHrP) is able to stimulate adenylate cyclase activity in isolated rabbit glomeruli. Maximal stimulations were reached at 10(-7) M of human PTHrP-(1-34) or rat PTH-(1-34) and showed a 3-3.3 fold increase over basal activity. The potency (EC50) values were close to 10(-9) M. The guanyl nucleotide GTP, at 10(-5) M, potentiated the effect of PTH and PTHrP but reduced their potency. The combined effect of maximal concentrations of PTHrP and PTH was not additive, and the PTH antagonist [Nle8.18, Tyr34]-bPTH-(3-34)amide inhibited both PTHrP- and PTH-stimulated adenylate cyclase activities. These findings suggest that PTHrP could affect glomerular function through changes in glomerular cAMP content by interaction with PTH receptors.
Previous studies showed that PTHrP exhibits renal vasodilating, arteriolar cAMP stimulating and receptor binding properties. The present experiments were designed to study whether PTHrP may influence renin secretion. Rat kidneys were isolated and single-pass perfused at constant flow and stabilized pressure. Exposures to PTHrP or PTH stimulated a dose-dependent renin release reaching similar Vmax. The affinity (0.1 nM) and threshold concentration (0.01 nM) for PTHrP were about 10 times lower than for PTH. Compared to 10 microM isoproterenol, the maximum renin responses to PTHrP were similar but of shorter duration. The PTHrP dose-response curve was not affected by 10 microM indomethacin. Administered simultaneously, PTHrP and PTH displayed no additive effects. PTHrP-induced renin release as well as the role of extracellular calcium were further studied in nonfiltering kidneys, which were perfused at a constant flow and stable pressure in a closed circuit. Basal renin release was inversely related with perfusate calcium and was depressed by the calcium ionophore BAY-K8644. PTHrP (100 nM) induced a 1.6-fold increase of basal renin release in normocalcic perfusate. Removing calcium abolished renin responses. PTHrP reversed the inhibiting effects of hypercalcic media or BAY-K8644 on basal renin release. The results support calcium-mediated renin stimulating properties for PTHrP, via PTH receptors, independently from baroreceptors, macula densa and prostaglandins.
1. We have previously reported that pharmacological concentrations (125nmol/l) of parathyroid hormone may stimulate renin release in the stable recirculating and non-filtering isolated rat kidney. 2. In the present study we have attempted to extend these initial observations by examining the concentration-related response of renin release to parathyroid hormone, using the same model of isolated kidney, and determining whether the effect of parathyroid hormone on renin release can be demonstrated by more direct approaches. Thus, the effects of parathyroid hormone on renin secretion were investigated in two other renal preparations: isolated rabbit glomeruli and isolated rat juxtaglomerular cells. 3. In the isolated kidney, rat parathyroid hormone significantly stimulated renin accumulation in the perfusate in a concentration-related manner with a threshold of 1 nmol/l. 4. In both glomeruli and juxtaglomerular cells bovine [Nle8,18,Tyr34]parathyroid hormone-(1-34)amide effectively and repeatedly stimulated renin release. These results imply that there is a direct stimulatory effect of parathyroid hormone on renin release. 5. We also examined the effect of [Nle8,18,Tyr34]parathyroid hormone-(1-34)amide during extracellular calcium buffering in the glomeruli. [Nle8,18,Tyr34]parathyroid hormone-(1-34)amide was uneffective in calcium-free medium. Increasing the extracellular ionized calcium concentration to 2.5 mmol/l increased the extent of stimulation in accordance with the reported ability of parathyroid hormone to block calcium channels and relax vascular smooth muscle cells. 6. These results provide further support for the role of parathyroid hormone as a direct mediator of renin secretion; moreover, the renin-stimulating action of parathyroid hormone may be mediated through the inhibition of calcium influx.
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25 patients with non complicated renal stones were treated by extracorporeal shockwave lithotripsy (ESWL) using Sonolith 3000 an electrohydraulic generator type. They were evaluated before, 15 days and 3 months after ESWL by renal scintigraphy, using for 15 of them technetium -99m dimer captosuccinic acid and technetium -99m-diethylene-triamine acetate for the last 10. This follow up scintigraphic study shows no reduction of glomerular filtration rate after ESWL but some focal parenchymal lesions. Very few of these lesions persist at 3 months. These parenchymal damages seem to be less frequent and less persistent than with piezo-electric lithotripter.
Three cases of ureteral endometriosis are reviewed. Computed tomography and magnetic resonance imaging show the mass which causes ureteral obstruction. The role of imaging modalities is discussed.
We have studied the normal and pathological aspects of seminal vesicles by MRI with body coil by correlation between imaging and pathologic findings after radical surgery of 63 patients with urogenital carcinoma. On normal T2 weighted sequence, the ampulla of the was deferens visible in 71% of cases exhibited a nodular low signal intensity. Seminal vesicles demonstrated an hypersignal in 79%, a low signal intensity in 19% and an heterogeneous signal intensity in 2%. Overall accuracy for the diagnosis of invasion was 77%. MRI was not efficient for bladder carcinoma (sensitivity: 1; specificity: 82%) but it was always gross infiltration (superior to 5 mm) than for prostatic carcinoma (sensitivity: 40%; specificity: 67%). The numerous false positives (15 cases) were related to hypointense normal (8 cases) or fibrous (6 cases) seminal vesicles and one case of atrophy. The false negatives were related to small invasion. Only, the negative predictive value was good value (overall NPV: 96%; bladder carcinoma NPV: 1; prostatic carcinoma NPV: 89%). A normal bilateral hypersignal of seminal vesicles permit to eliminate a gross invasion.
Pregnancy is associated with morphologic alterations of the urinary tract, of which physiological ureterohydronephrosis is the most common. Acute pyelonephritis and obstruction by stones are the two most frequent urinary tract diseases of pregnancy. Medical imaging aims at differentiating physiological ureterohydronephrosis from obstruction and at detecting infections. Ultrasonography plays a central role. Limited roentgenographic investigations can be performed during the second and third trimester. Magnetic resonance imaging can be expected to gain more widespread use in the near future.
In an attempt to define the best conditions for an adjunctive treatment of residual colonic microtumors by photodynamic therapy (PDT), an experimental model has been defined. S.c. HT29 colonic-cancer-cell tumors grown in nude mice were used and, 48 hr after i.p. administration of 30 mg/kg Photofrin (PH), laser illumination was performed with 75 or 150 Joules/cm2. The efficiencies of 2 lasers, the classically used rhodamine laser (RL) and a copper metal vapor laser (CMVL), were compared. The effects of PDT were assessed by histological and immunocytochemical (detection of a digestive enzyme, dipeptidyl-peptidase IV, as a marker of cell viability) follow-up and by the growth curve of the tumors after illumination. We conclude that, although the depth of necrosis resulting from PDT was nearly 3 mm at 75 J/cm2 and nearly 4-5 mm at 150 J/cm2 with both lasers, complete necrosis was obtained only with the CMVL at 150 J/cm2 (in 50% of the tumors). Under the other conditions, a layer of unaffected cells persisted at the pole opposite to laser illumination, resulting in growth curves lower than but parallel to those of the controls. Analysis of drug concentrations in the tumors and various organs, 48 hr after injection, i.e., at the time of laser illumination, revealed the presence of 21 micrograms/g dry weight PH in the tumors. The tumor vs. host-organ ratios were equal to or higher than 1 for the small bowel, colon, stomach, lung, skin and muscle. In contrast, the ratios were below 1 for the spleen, pancreas, kidney and liver.
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Conservative surgery is proposed by many authors for small kidney tumors. We reviewed retrospectively the pathology reports of 727 operated patients. In 257, tumor diameter was less than or equal to 5 cm, in 158 it was less than or equal to 4 cm, and in 78 it was less than or equal to 3 cm. The number of multiple tumors were 26 (10.1%), 17 (10.75%), and 10 (12.8%) respectively, which means that there is a 10% potential risk of leaving a tumor in situ in case of conservative surgery. There is no security size limit. These parameters have to be considered before proposing conservative surgery for small kidney tumors as a standard treatment.
Local transrectal hyperthermia of the prostate was used to treat 16 poor surgical risk patients who had an indwelling catheter because of chronic urinary retention caused by benign prostatic hypertrophy. We used the Brucker (Prost-care) model with a rectal applicator, a water cooling system and a microwave generator operating at 915 MHz. Intraprostatic temperatures of 42 degrees to 44 degrees C were measured by a radiometric system. 12 patients received a complete treatment which consists in 6 to 10 sessions of one hour and was controlled at least one month later. 8 of them no longer need a catheter. Uroflowmetry was between 7.5 and 17.6 ml/sec and residual urine appreciate by ultrasounds was less than 60 cm3.
The authors report a case of rhabdomyosarcoma in a 17 year old boy which recurred after combination chemotherapy and radical prostatectomy, followed by death of the patient due to haematological complications of second-line chemotherapy. The diagnosis of these rhabdomyosarcomas is facilitated by the various immunohistochemical stains now available. Chemotherapy is undeniably effective and, combined with surgery and radiotherapy, ensures a 5-year survival of 47% to 93% depending on the stage. The first-line chemotherapy avoids the need for radiotherapy in the early stages and allows less mutilating surgical procedures, while maintaining the survival rate.
Magnetic resonance imaging (MRI) of the normal kidney shows in T1 weighted sequence a spontaneous corticomedullary differentiation. In case of ureteral obstruction the corticomedullary differentiation tends to disappear, the medullary signal intensity in T1 weighted sequence is lower and the whole kidney signal intensity in T2 weighted sequence is greater in acute phase. 16 patients with lithiasis ureteral obstruction were evaluated in MRI study. A T1 weighted S.E. 500/28 sequence in axial and frontal planes (7 mm thick-section) and a T2 weighted E.G. 2000/40 sequence in axial plane were used to study the hydronephrotic kidney and to compare it with contralateral normal kidney. Ultrasounds and intravenous pyelography (IVP) were performed to assess the renal dysfunction. MRI realize a morphologic study of the kidney which can be compared with ultrasounds and IVP. MRI assess renal function by the signal intensity but the time of obstruction and the time of medical treatment before MRI are of interest.
Cancer of the prostate mainly occurs in elderly men and is becoming more frequent as the general European population gets older. Only through continuing progress in the already well developed therapeutic methods will mortality due to this cancer be curtailed. Prognosis of cancer limited to the prostate gland has been improved by radical surgery which reduces morbidity and mortality and advanced radiotherapy techniques. The potentially curable forms, still mainly detected by systematic rectal examination, can be defined better with magnetic resonance imagery and biological markers. Hormonal treatment for more extended or metastatic cancers is now based on several effective, well tolerated products. Chemotherapy has not been able to solve the problem of hormonal escape for which other therapeutic techniques are now under study.
Magnetic Resonance Imaging of 20 patients with local prostatic carcinoma was correlated with pathological findings after radical prostatectomy. The tumor was always seen with an hyposignal, associated in 6 cases with benign prostatic hyperplasia. Extracapsular extension was correctly evaluated (17 cases/20). There were 6 false positive diagnosis of seminal vesicles extension among 40 cases because of an hyposignal in intact vesicles and one false negative diagnosis. Magnetic Resonance Imaging is a good exam to appreciate loco-regional extension of prostatic carcinoma.
Amyloidosis of the bladder associated with systemic amyloidosis secondary to rheumatoid arthritis is a rare disease. Due to the absence of routine screening, its incidence appears to be understimated and only 11 cases, all symptomatic, have been reported in the literature. The symptoms of this disease are dominated by macroscopic haematuria, always massive, which may be life-threatening. We report a case in which the severity of this haematuria required emergency cystectomy to ensure haemostatis, which revealed amyloidosis on histological examination.