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Biomedical subjects

J Simon

Publications and source records attributed to J Simon.

At least 217 records · Page 12Linked to original sources
PubMed1997

[The need of prolonged BCG treatment in superficial bladder cancer is suggested by the development of a peripheral immune response induced by BCG].

Optimal duration of immunotherapy treatment by BCG for the prevention of recurrences of superficial bladder cancer is still unknown. We have studied the evolution and duration of the cellular immunity response at the peripheral level after BCG intravesical instillations. Our results show that immunity activation after BCG is of short duration and don't take more than 6 months. Our results support, strengthen and partially allow to explain the utility of maintenance treatment by BCG following 6-weekly instillations.

Adjuvants, Immunologic↗
PubMed1997

Conservative management of ureteric stones.

The authors review the current conservative management of ureteric stones. The physiopathology of the renal colic is analyzed with its implications in the medical treatment. The role of NSAID is enhanced. Stone size and stone location are to be considered when evaluating the possibility of spontaneous passage of the stone. Stones less than 3 mm in diameter of the lower ureter will pass spontaneously in 90% of the cases while stones more then 6 mm in the upper ureter will not pass in most cases. The role of stone dissolution in uric acid and cystine stones is discussed. SWL is not controversial in the management of upper stones less than 15 mm in size. The authors report their experience with SWL of ureteric stones in upper, middle or lower ureteric stones with a success rate of respectively 87%, 65% and 84%.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed1997

[Urinary lithiasis: epidemiology and physiopathology].

Urolithiasis has an incidence of about 12% in men and about 5% in women before the age of 70 years. Several epidemiological factors are involved in the predisposition to the urinary stone disease, notably: age, sex, race, climate, geography, profession, social class, nutritional factors and inherent genetic particularities. A number of physicochemical mechanisms govern lithogenesis, passing from saturation and supersaturation of urine to nucleation, crystallization and crystal growth to clinically significant sizes when the inhibition mechanisms are overwhelmed or absent. Generally urinary stone are of diverse aetiologies, that can essentially be grouped in calcium, uric acid, cystine and magnesium ammonium phosphate stones with subgroups in relation to the varied pathophysiological mechanisms involved in each case.

Adult↗
PubMed1997

[Diagnostic approaches in calculi].

Diagnosis of the stone is based on anamnesis, physical examination and radiological investigation. Anamnesis and physical examination need to be supported by knowledge of the neuroanatomy of the urinary upper tract. Radiological investigation should be both non toxic and effective. Gold standard radiological examination in the evolution of urolithiasis remains the echography. Urography leads to be replaced by helical scanner less toxic and more efficient. This review tries to present the different possibilities of investigations in the diagnosis of urolithiasis.

Colic↗
PubMed1997

[Medical treatment of ureteral calculi].

Antiinflammatory drugs are the first choice in the treatment of the acute nephretic colic. This is due to their fast and direct action on the ureteral wall. The use of antispasmodics are still controversial and opioïds are not indicated. During the acute crisis, an hydric restriction should be associated to the medical treatment. After the crisis an increase of diuresis could help to "wash out" the stone. A spontaneous elimination can be expected, especially if the stone is small and located in the third part of the ureter. The ureteral rupture is rare but serious and must be treated by antibiotics and some time to be drained. The rapidity of a more aggressive treatment is function of numerous factors.

Acute Disease↗
PubMed1997

[Calculi: interventional treatment].

Extracorporeal shock wave lithotripsy is actually the most popular treatment in the urolithiasis. However, different factors influence the choice of the best treatment. Great progresses appeared in the conception of performing endoscopic material which led to minimize morbidity. Percutaneous approach is very popular but require expensive material and trained operator. Indications for open surgery were reduced but didn't completely disappear. We review in the next paragraph the literature of the last five years.

Adolescent↗
PubMed1997

[Complications of ureteroscopy].

Improvements in ureteroscope design and technique have led to increase the success of diagnostic and therapeutic ureteroscopy while decreasing morbidity. Most important complications have been categorized in the following manner: access complications, preoperative complications and early and late postoperative complications.

Endoscopes↗
PubMed1997

[A metabolic approach to patients with calculi].

Metabolic evaluation remains cornerstones in the treatment and prevention of recurrence in patients with urolithiasis. The various chrystallographic, biological and radiological investigation should be done only in patients presenting recurrence and/or given risks factor of recurrences. The choice of the investigation is guided by the knowledge of the pathophysiological phenomena and should thus be adapted to each patient. Results should be analyzed by a multidisciplinary team. This aspect will be developed in the next paragraph.

Biology↗
PubMed1996

[Homocysteine, a less well-known risk factor in cardiac and vascular diseases].

Hyperhomocyst(e)mia (Hcy) negatively influences vascular endothelium and coagulation factors. Association of Hcy with premature arteriosclerosis (rather than atherosclerosis), stroke, myocardial infarction and peripheral arterial and venous disease was proved in clinical and epidemiological studies, even as the association with conventional risk factors like age, male sex, smoking, hypertension and hypercholesterolemia. Vitamin substitution of folates, vitamin B6 and B12 decreases Hcy blood levels, however definite evidence is still lacking, whether it results in lower incidence and mortality from cardiovascular diseases. Therefore clinical and epidemiological studies are necessary. Before the grant-application we proved in a pilot study significantly higher Hcy levels in 97 patients with manifest ischaemic heart disease than in 37 controls.

Arteriosclerosis↗
PubMed1996

A new set of primers for the detection of Toxoplasma gondii in amniotic fluid using polymerase chain reaction.

A new PCR system including a pair of primers, a probe and an internal control were designed from the B1 gene of Toxoplasma gondii. The system described allowed the detection of less than 10 tachyzoites of the RH strain of T. gondii. Among 21 amniotic fluid samples, this system diagnosed the cases of congenital toxoplasmosis which were simultaneously diagnosed using mice inoculation, in vitro culture, and serology from both amniotic fluid and fetal blood. These results show that these new primers allow for a highly sensitive detection of T. gondii DNA.

Amniotic Fluid↗
PubMed1996

Alteration of lymphocyte membrane phospholipids and intracellular free calcium concentrations in hyperlipidemic subjects.

Hypercholesterolemia has been proposed to influence cell functions via changes in membrane composition. The aim of the present study was to determine whether the membrane phospholipid composition of human lymphocytes is modified in hypercholesterolemia and whether these changes are accompanied by functional modifications. The phospholipid fatty acid contents and intracellular free calcium concentrations were determined in peripheral blood lymphocytes from 13 subjects with serum total cholesterol levels ranging from 4.6 to 8.8 mmol/l. The spontaneous basal rate of thymidine incorporation in lymphocyte of hypercholesterolemic individuals increased, while its relative stimulation by ConA was less effective. Important changes in membrane lipid composition, consisting mainly of decrease of the mass of phospholipids, and of associated polyunsaturated fatty acids were observed in hypercholesterolemia. In contrast, the cell cholesterol content was significantly increased. The intracellular free calcium concentration was enhanced and strongly associated with circulating cholesterol levels, cell cholesterol content and phospholipid fatty acids. These results indicate that hypercholesterolemia is accompanied by profound changes in lymphocyte membrane lipid composition and Ca(2+) handling.

Calcium↗
PubMed1996

Induction of tumor necrosis by delta-aminolevulinic acid and 1,10-phenanthroline photodynamic therapy.

delta-Aminolevulinic acid (ALA) causes cells to accumulate protoporphyrin IX (Proto) and heme. Exposure to light in vitro causes intracellular Proto to initiate formation of singlet oxygen molecules, leading to self-destruction. This photoactivated destruction by ALA in vitro is enhanced by addition of the tetrapyrrole modulator 1,10-phenanthroline (Oph), which increases cellular accumulation of Proto. Here we significantly extend this idea by evaluating the efficacy of ALA and Oph photodynamic therapy of solid tumors in vivo. Methylcholanthrene-induced fibrosarcoma (Meth-A) cells were used, which lead to the formation of solid tumors when implanted into syngeneic recipients. Initially, suspensions of Meth-A cells were treated in vitro with combinations of ALA and Oph. Meth-A cells in suspension accumulated 6-fold greater amounts of Proto (P < 0.05) after 3-h incubation with ALA and Oph than when incubated with ALA alone, and were also more susceptible to subsequent photoactivated cell lysis in vitro. Similarly, solid Meth-A tumors grown in syngeneic BALB/c mice accumulated significant (P < 0.05) amounts of Proto 3 h after in vivo treatment with ALA, and Oph synergized with ALA to significantly (P < 0.05) enhance the induction of Proto in these tumors. ALA and Oph-based phototreatment of mice bearing Meth-A solid tumors resulted in necrosis of tumors, as determined by a significant reduction in both size and histopathology, with little damage to surrounding normal tissue. These data directly demonstrate the experimental usefulness of Proto modulators for ALA-based photodynamic therapy in the treatment of solid tumors in vivo and provide a rationale for their potential application in a multitude of tumor types.

Aminolevulinic Acid↗
PubMed1996

The diverse series of recombinant P2Y purinoceptors.

A cDNA encoding a P2Y purinoceptor was originally cloned from chick brain and the bovine and human homologues have recently been obtained. These are seven-transmembrane-domain polypetides, i.e. G protein-coupled receptors. When activated by agonists, this P2Y receptor mobilizes intracellular Ca2+ and has been shown to be coupled to inositol-1,4,5-trisphosphate formation. Its pharmacology has been established in several expression systems, using both ligand binding and functional responses: 2-methylthioATP has the highest potency of nucleotides and derivatives tested, while UTP and alpha, beta-methylene ATP are inactive. This was hence assigned as a new subtype of the pharmacologically defined P2Y receptors, P2Y1. P2Y1 receptors are exceptionally abundant in the brain. A P2U receptor reported by others can be designated P2Y2. Another P2 receptor subtype, P2Y3, now cloned as a cDNA from the brain and expressed in oocytes and in transfected cells, shows a quite different ligand potency profile to the first two. A fourth subtype is expressed primarily in certain haemopoietic cells and in cardiac muscle. A putative fifth subtype is expressed only in T lymphocytes, upon activation. Yet other P2Y subtypes are indicated by recent cloning studies. The amino acid sequences of all of these P2 receptors, while displaying some homology, are strikingly diverse: they form a separate and unusual new family in the G protein-coupled receptor main superfamily.

Animals↗
PubMed1996

Guidelines for the use of magnetic resonance techniques in monitoring the treatment of multiple sclerosis. US National MS Society Task Force.

Because of the major difficulties in measuring clinical end points in multiple sclerosis (MS) treatment trials, there has been much enthusiasm for using magnetic resonance imaging (MRI) findings as an alternative outcome. To provide international consensus guidelines for the use of MRI in MS clinical trials, a task force of the US National MS Society was convened. The recommendations of the task force are presented in this review. Given the high sensitivity for detecting pathological activity in relapsing-remitting and secondary progressive MS, monthly T2-weighted and gadolinium-enhanced brain MRI is an excellent tool for short-term exploratory trials of new agents where it serves as the primary end point; in particular, failure to demonstrate a reduction in lesion activity avoids the time, cost, and risks of a larger clinical end point study. However, conventional MRI findings have a limited correlation with disability in established MS. The primary end point of a definitive trial should therefore be clinical, although serial MRI at 6- to 12-month intervals is a useful secondary end point in providing an index of pathological progression. In trials of patients presenting with clinically isolated syndromes suggestive of MS, MRI findings can be used in the entry criteria, and as a secondary outcome measure, but conversion to clinically definite MS should be the primary outcome. The pathological substrates of irreversible disability are demyelination and axonal loss. Putative magnetic resonance markers for these processes include decreased N-acetylaspartate on proton magnetic resonance spectroscopy, decreased magnetization transfer ratios, hypointensity on T1-weighted images, and loss of short T2 water fractions, some of which relate more closely to disability than conventional MRI findings. Further technical developments should lead to more accurate quantitation, greater pathological specificity, and stronger clinical correlations.

Clinical Trials as Topic↗
PubMed1996

Ca(2+)-binding domain VI of rat calpain is a homodimer in solution: hydrodynamic, crystallization and preliminary X-ray diffraction studies.

The 21-kDa calcium-binding domain (VI) of the small subunit of rat calpain II has been expressed in Escherichia coli, purified, and crystallized. Two orthorhombic crystal forms have been obtained: space group P2(1)2(1)2(1) with a = 50.3, b = 56.5, c = 141.3 A; and space group C222(1) with a = 69.4, b = 73.9, c = 157.4 A. Diffraction data have been collected to 2.4 A. Sedimentation equilibrium, dynamic light scattering, and gel-permeation chromatography indicate that domain VI exists as a homodimer in solution. In accordance with the protein's behavior in solution, each crystal form contains two molecules per asymmetric unit. Screening for heavy-atom derivatives is in progress. To decrease the sensitivity to mercurials and to aid in the search for useful derivatives, Cys-to-Ser mutants have been prepared, expressed, and crystallized.

Animals↗
PubMed1996

Interlaboratory comparison of polymerase chain reaction for the detection of Toxoplasma gondii DNA added to samples of amniotic fluid.

To investigate the accuracy of the polymerase chain reaction (PCR) method for the detection of Toxoplasma gondii in clinical specimens, aliquots of amniotic fluid to which known amounts of Toxoplasma gondii DNA had been added were tested by five European Centres. Four laboratories were able to detect DNA at levels equivalent to ten tachyzoites or less, including two that detected DNA equivalent to a single parasite. Two laboratories erroneously found one of eight negative control samples to be positive. These findings confirm that the high level of sensitivity associated with the PCR method can be readily achieved under routine laboratory conditions, but they also underscore the potential for both false-positive and false-negative findings to occur. Furthermore, the results confirm the urgent need for an external quality assurance scheme to support laboratories employing PCR in a clinical context for the detection of Toxoplasma gondii.

Amniotic Fluid↗