[Malignant mesothelioma of the testicular tunica vaginalis]

Malignant mesothelioma of the tunica vaginalis, a rare tumour, affects men over the age of 50 years and presents in the form of a testicular mass. It is rarely suspected preoperatively and the diagnosis is suggested by the presence of numerous nodules in the tunica vaginalis. This tumour has a high metastatic potential and raises the problem of numerous local recurrences. The diagnosis is histological with negative biological markers. Treatment is difficult; the first step must consist of surgery. The indications for radiotherapy have yet to be defined.

Early versus delayed hormonal therapy in advanced prostate cancer

OBJECTIVES

To review current thinking on the optimum timing of androgen deprivation in the treatment of patients with advanced prostatic cancer (PCa).

INTRODUCTION

Although the beneficial impact of androgen deprivation has been well documented in patients with advanced PCa, a number of questions remain to be answered about the best therapeutic schedule for hormonal therapy. One such important issue is whether androgen deprivation should be introduced at the time of diagnosis or delayed as long as the patient remains asymptomatic.

CONCLUSIONS

For many years urologists have delayed hormonal treatment for patients with advanced PCa, however, this has recently been reassessed. It is now well established that early hormonal treatment significantly delays the onset of disease progression, which may correlate with an improved quality of life. Although several studies indicate that early treatment has a beneficial effect on survival, this has not been definitely proven, and results from further studies are needed before final conclusions can be drawn. However, apart from men wishing to maintain their sexual activity, early androgen deprivation should be proposed in all patients with advanced PCa.

A new plasma-based method to promote cell adhesion on micrometric tracks on polystyrene substrates

A new procedure has been developed in order to obtain heterogeneous polymer surfaces for the promotion of cell adhesion. For this purpose, a microelectronic photosensitive resin was spin coated on polystyrene (PS) substrates. The resin was then submitted to UV light irradiation through a mask and partially developed. The sample was further submitted to a plasma oxygen discharge prior to dissolution of the remaining resin. The characterization by time of flight secondary ion mass spectrometry (ToF SIMS), X-ray photoelectron spectroscopy (XPS), and dynamic contact angle (DCA) allowed us to conclude that hydrophilic paths were created on the more hydrophobic PS substrate together with the complete removal of the resin. In order to optimize cell adhesion contrast, the modified surfaces were then conditioned with a solution containing both a surfactant (pluronic F68) and a protein. Two different proteins were tested (collagen I and fibronectin). PC12 cell cultures on those conditioned surfaces showed that cell adhesion occurs only on the hydrophilic tracks. ToF SIMS spectra and images recorded on those substrates revealed the presence of the proteins only in the hydrophilic tracks. In the same time, the surfactant is suspected to adsorb mainly on the hydrophobic areas of the samples.

Apolipoprotein E4 allele as a predictor of cholinergic deficits and treatment outcome in Alzheimer disease

Apolipoprotein E (apoE) is critical in the modulation of cholesterol and phospholipid transport between cells of different types. Human apoE is a polymorphic protein with three common alleles, APO epsilon 2, APO epsilon 3, and APO epsilon 4. ApoE4 is associated with sporadic and late-onset familial Alzheimer disease (AD). Gene dose was shown to have an effect on risk of developing AD, age of onset, accumulation of senile plaques in the brain, and reduction of choline acetyltransferase (ChAT) activity in the hippocampus of AD subjects. To characterize the possible impact of the apoE4 allele on cholinergic markers in AD, we examined the effect of apoE4 allele copy number on pre- and postsynaptic markers of cholinergic activity. ApoE4 allele copy number showed an inverse relationship with residual brain ChAT activity and nicotinic receptor binding sites in both the hippocampal formation and the temporal cortex of AD subjects. AD cases lacking the apoE4 allele showed ChAT activities close or within age-matched normal control values. The effect of the apoE4 allele on cholinomimetic drug responsiveness was assessed next in a group (n = 40) of AD patients who completed a double-blind, 30-week clinical trial of the cholinesterase inhibitor tacrine. Results showed that > 80% of apoE4-negative AD patients showed marked improvement after 30 weeks as measured by the AD assessment scale (ADAS), whereas 60% of apoE4 carriers had ADAS scores that were worse compared to baseline. These results strongly support the concept that apoE4 plays a crucial role in the cholinergic dysfunction associated with AD and may be a prognostic indicator of poor response to therapy with acetylcholinesterase inhibitors in AD patients.

Combination chemotherapy with vindesine-ifosfamide-cisplatin (VIP) in locally advanced unresectable stage III and in stage IV non-small cell lung cancer: a phase II trial

The efficacy and toxicity of a regimen adding ifosfamide to the more classical cisplatin-vindesine combination was studied in patients with advanced non-small cell lung cancer. Sixty-four good performance patients with inoperable stage III or stage IV were treated with VIP: vindesine 3 mg/m2 days 1 and 8, ifosfamide 1200 mg/m2 and platinum 30 mg/m2 days 1, 2 and 3, repeated every 4 weeks, up to a maximum of six cycles. Response rate, clinical data and radiological tests were rigourously reviewed by a panel. Overall response rate was 39% (95% confidence interval, 27%-51%) with three patients achieving a complete response; response rate in stage III was 48%. Median survival was 9 months. Toxicity consisted mainly of bone marrow toxicity and nausea/vomiting, but was manageable. There was no renal toxicity greater than grade 2, four severe infections, but no treatment-related deaths.

CONCLUSION

VIP as mentioned above is very active in good performance patients with advanced non-small cell lung cancer. Its activity, together with its manageable toxicity--without severe renal or pulmonary toxicity--makes it an attractive candidate for induction chemotherapy.

Association of apolipoprotein E genotype with brain levels of apolipoprotein E and apolipoprotein J (clusterin) in Alzheimer disease

This study examines the relationship between the levels of apolipoprotein E (apoE) and apolipoprotein J (apoJ, also designated as clusterin) as a function of apoE genotype in the hippocampus and cortex of Alzheimer disease (AD) subjects. These two lipophilic proteins which are involved in the maintenance of lipid homeostasis are both synthesized in the brain by astrocytes. Results indicate a reduction of apoE levels in the hippocampus and frontal cortex that is proportional to the apoE4 allele dose. Conversely, apoJ (clusterin) levels were found to increase proportionately to the number of apoE4 allele dose. These results suggest a compensatory induction of apoJ (clusterin) in the brain of apoE4 AD subjects showing low brain levels of apoE.

Control of the redox potential in c-type cytochromes: importance of the entropic contribution

The enthalpic and entropic components of the redox free energy variation of cytochrome c553 from Desulfovibrio vulgaris Hildenborough and its mutant Y64V, flavocytochrome b2 from Saccharomyces cerevisiae, and the different hemes of cytochromes c3 from Desulfovibrio vulgaris Miyazaki and Desulfovibrio desulfuricans Norway have been determined in 0.1 M Tris-HCl pH 7.0 (7.6 for cytochromes c3) at 25 degrees C by using nonisothermal potentiometric titrations. The set of available experimental data demonstrates that the entropic component plays an important role in the control of the redox potential in c-type and b-type cytochromes. The variation of the entropic component within the class of cytochromes characterized by a positive value of E degrees ' is proposed to be mainly determined by the variation of the exposure of the heme propionates to the solvent. In the case of tetraheme cytochromes c3, the thermodynamic characteristics vary largely among the hemes belonging to the same molecule, which reflects the environmental peculiarities of each heme and also the heme-heme redox interactions. This study substantiates the existence of compensatory effects between large and opposite contributions to E degree ' predicted by all the current theoretical models which are based on electrostatic free energy calculations.

In vitro and in vivo evaluation of a small caliber vascular prosthesis fixed with a polyepoxy compound

A small caliber vascular prosthesis obtained from an ovine internal thoracic artery (3.8-4.5 mm ID) fixed with a polyepoxy compound and treated with heparin has been evaluated. Cytocompatibility was evaluated in vitro using human endothelial cells (HEC). HEC were obtained from human saphenous vein and cultivated in culture medium supplemented with 25% human serum. Graft segments were rinsed using a standard protocol proposed by the manufacturer. Tissue reaction was tested on a rabbit model of subcutaneous implantation. The patency rate and healing patterns were evaluated comparatively with polytetrafluorethylene (PTFE) 4 mm ID prosthesis in a canine model of carotid interposition. Cytocompatibility assay showed that there was low adhesion on vascular grafts (20 +/- 2% of endothelial cells seeded) and no growth of HEC on the graft surface. The graft patency rate was 55% in both groups, and actuarial freedom from occlusion was not different at 3 months (37.7 +/- 15% in Denacol-fixed grafts versus 38.1 +/- 14% in PTFE). Histological studies on the biological grafts shows a frequent neointimal hyperplasia at the anastomosis (5/12), a lack of endothelial cells lining the graft surface, a good preservation of the media, and a moderate inflammatory response in the adventicia. The Denacol-fixed graft has presented excellent surgical properties and preservation of the histological structure. Nevertheless, the patency rate was not improved when compared with the PTFE control graft.

Immediate and delayed tolerance of iohexol and ioxaglate in lower limb phlebography: a double-blind comparative study in humans

RATIONALE AND OBJECTIVES

We compared the tolerance and efficacy of iohexol-300, a nonionic low-osmolar monomer, with those of ioxaglate-320, an ionic low-osmolar dimer, in lower limb phlebography.

METHODS

One hundred twenty inpatients were randomly divided into two groups in this double-blind comparative study. Two hundred milliliters of contrast medium (100 ml per leg) was injected intravenously. The immediate tolerance was classified as discomfort (i.e., sensation of warmth, pain, coldness related to the injection) and adverse events occurring up to 1 hr after administration. Delayed tolerance was followed up to 8 days after the examination. The main parameter was immediate adverse events. Image quality was assessed by a radiologist using a visual analog scale.

RESULTS

The number of immediate adverse events was significantly higher in the ioxaglate group (p < .02). The more frequent events were digestive disorders and skin rashes; 13 of these events were reported in the ioxaglate group, but none were reported in the iohexol group (p < .001). The other parameters were not significantly different in the two groups.

CONCLUSION

We found a similar efficacy and a better tolerance of iohexol-300 than ioxaglate-320 in lower limb phlebography.

Enzyme-linked hyaluronectin: a unique reagent for hyaluronan assay and tissue location and for hyaluronidase activity detection

Several techniques for assaying and localizing hyaluronan (HA), all based on the affinity to hyaluronan of proteins isolated from cartilage, chondrosarcoma, or brain, have been proposed. We show here that a unique reagent, alkaline phosphatase-linked hyaluronectin, can be used to assay hyaluronan in biological fluids or tissue extracts (enzyme-linked sorbent assay method) and to characterize it in cells or tissue sections in two steps: reagent incubation and staining. Results of assays in biological fluids or tissue extracts showed a good correlation with results of the previously described technique using antibodies to detect hyaluronectin bound to a plastic microtest plate (B. Delpech et al., 1985, Anal. Biochem. 149, 555-565) for both low concentrations (< 1 mg/liter, r = 0.973, P < 0.001) and high concentrations (> 1 mg/liter, r = 0.953, P < 0.001). The interassay variations were 8.5% when the assay was performed at 4 degrees C and 18.5% at 37 degrees C. The intraassay variations under those conditions were, respectively, 14.4 and 6.5%. Tissue HA could be detected easily with the reagent, as shown in fetal tissues and in tumors. Specificity of the reaction was controlled either by blocking the reagent with an excess of hyaluronan (which was not possible with other glycosaminoglycans) or by destroying tissue hyaluronan with streptomyces hyaluronidase. Alkaline phosphatase-linked hyaluronectin was also used to assay hyaluronidase activity in several biological fluids. One-hour incubation of hyaluronidase preparations on HA-coated plates made it possible to detect as low as 1 mU bovine testis hyaluronidase and 0.1 mTRU streptomyces hyaluronidase. Four-hour incubation made it possible to detect activity in a 1/12,500 dilution of human serum.

EPR and redox characterization of ferredoxins I and II from Desulfovibrio vulgaris Miyazaki

Detailed redox titrations monitored by EPR and UV-visible spectroscopies have been carried out on the dimeric ferredoxins I and II from Desulfovibrio vulgaris Miyazaki. Ferredoxin II contains a unique [4Fe-4S] cluster per subunit characterized by a midpoint potential of -417 mV at 24 degrees C. The enthalpic and entropic contributions to the redox free energy variation of this cluster have been determined from the temperature dependence of the midpoint potential and compared to the data reported for other iron-sulfur proteins. The molecular arrangement of the two subunits is such that two [4Fe-4S]i+ clusters are magnetically coupled in the fully reduced state of the protein. Ferredoxin I contains one [3Fe-4S] and one [4Fe-4S] cluster per subunit, whose spectral and redox properties are very similar to those of the same clusters in ferredoxin III from Desulfovibrio africanus. The strong heterogeneity in the redox properties of the [3Fe-4S] center supports a bridging position between the N-terminal and C-terminal parts of the protein.

RP 73870, a gastrin/cholecystokinin-B receptor antagonist with potent anti-ulcer activity in the rat

RP 73870, the racemic potassium salt of (([N-(methoxy-3-phenyl)-N-(N-methyl-N-phenyl-carbamoylmethyl)- carbamoylmethyl]-3-ureido)-3-phenyl)-2-ethylsulfonate-(RS) is a potent, reversible antagonist of both gastrin and cholecystokinin-B receptors in guinea pig and rat tissues. This compound is a potent inhibitor of pentagastrin-stimulated gastric acid secretion in the perfused rat stomach. RP 73870 also inhibits basal gastric acid secretion in the rat, although at doses higher than that required for inhibition of pentagastrin-stimulated gastric acid secretion. RP 73870 is a potent inhibitor of aspirin-induced gastric damage in the rat. In the prevention of aspirin-induced gastric damage, RP 73870, given p.o., was 10-fold less potent than when given i.v. RP 73870 was as potent as a H2 receptor antagonist or proton pump inhibitor in the prevention of cysteamine-induced duodenal ulcers in the rat. Relative to other gastrin/cholecystokinin-B antagonists, RP 73870 demonstrates greater affinity to gastrin binding sites, and possesses a unique spectrum of in vivo biological activities appropriate for an anti-ulcer indication.

Structural organization of the Ni and (4Fe-4S) centers in the active form of Desulfovibrio gigas hydrogenase. Analysis of the magnetic interactions by electron paramagnetic resonance spectroscopy

The Desulfovibrio gigas hydrogenase is a typical (NiFe) hydrogenase containing a Ni center and three FeS centers, one [3Fe-4S] and two [4Fe-4S] clusters. When the enzyme is activated under hydrogen gas, the Ni center becomes paramagnetic, giving a characteristic electron paramagnetic resonance (EPR) signal with g values at 2.19, 2.14 and 2.01, the Ni-C signal. Two redox states of the enzyme can be prepared, in which the [4Fe-4S] clusters are either diamagnetic or paramagnetic. In this latter state, the magnetic coupling between metal centers induces both the appearance at low temperature of a complex EPR spectrum, the split Ni-C signal, and a significant enhancement of the relaxation rates of the Ni center. Good simulations of the split Ni-C signal recorded at three different microwave frequencies (X-band, Q-band, and S-band) are obtained by using a model based on a point dipole approximation of the dipolar and exchange interactions between paramagnets. The spectral analysis demonstrates that only one [4Fe-4S]1+ cluster is significantly coupled to the Ni site and provides a detailed description of the relative arrangement of the two centers. In addition, the magnetic characteristics of this [4Fe-4S]1+ cluster can be deduced from the simulations. Moreover, the spin-spin and spin-lattice relaxation times of the interacting centers were measured in the two redox states of the enzyme, either by power saturation and pulsed EPR experiments at low temperature or from the broadening of the EPR lines at higher temperature. The relaxation behavior of the Ni center is well explained by using in the theoretical analysis, the set of structural and magnetic parameters deduced from the spectral simulations. Our structural conclusions on the active D. gigas hydrogenase are compared to the preliminary data of a low-resolution crystal structure of the oxidized enzyme [Volbeda, A., Piras, C., Charon, M. H., Hatchikian, E. C., Frey, M., & Fontecilla-Camps, J. C. (1993) News Lett. Protein Crystallogr. 28, 30-33].

Characterization of two nuclear mammalian homologous DNA-pairing activities that do not require associated exonuclease activity

We have developed an assay to study homologous DNA-pairing activities in mammalian nuclear extracts. This assay is derived from the POM blot assay, described earlier, which was specific for RecA activity in bacterial crude extracts. In the present work, proteins from mammalian nuclear extracts were resolved by electrophoresis on SDS/polyacrylamide gels and then electrotransferred onto a nitrocellulose membrane coated with circular single-stranded DNA (ssDNA). The blot obtained was incubated with a labeled homologous double-stranded DNA (dsDNA). Homologous pairing between the ssDNA and the labeled dsDNA was detected by autoradiography as a radioactive spot on the membrane. In nuclear extracts from mammalian cells, we found two major polypeptides of 100 and 75 kDa, able to promote the formation of stable plectonemic joints. Joint molecule formation required at least one homologous end on the dsDNA, but either end of the dsDNA could be recruited to initiate the reaction. For each polypeptide, the reaction required divalent cations such as Mg2+, Ca2+, or Mn2+. Although ATP was not necessary, ADP was inhibitory in each case. Unlike most of the known eukaryotic DNA-pairing proteins, both activities identified here were able to promote the formation of joint molecules without requiring an associated exonuclease activity. In addition, these two proteins were detected in cell lines from different tissues and from different mammalian species (human, mouse, and hamster).

Above-knee femoropopliteal bypass grafting using endothelial cell seeded PTFE grafts: five-year clinical experience

Early clinical trials using endothelial cells seeded vascular grafts failed to confirm the successful results observed in animals. Differences in seeding methods could at least partially account for this failure. The purpose of the present study was to ascertain the feasibility and intraoperative efficacy of a two-stage technique that allowed high-density seeding as in animals. The first stage of the technique consists of harvesting an autologous vein specimen under local anesthesia followed by enzymatic isolation and in vitro culture of endothelial cells. The second stage is vascular repair. During the procedure the prosthesis is precoated with autologous whole blood or plasma for 30 minutes and seeded at high density with endothelial cells incubated for 45 minutes. Between May 1988 and June 1993, 32 patients were enrolled in this study. In 11 of them, however, the technique could not be completed for various reasons including preoperative infarction in one case, failure to achieve isolation and/or cell cultures in nine cases, and contamination of cell culture in one case. Twenty-one patients (18 men and 3 women) whose mean age was 62 years (range 38 to 78) underwent above-knee femoropopliteal bypass using an endothelial cell seeded polytetrafluoroethylene graft (7 mm). The indication for surgery was intermittent claudication in 20 patients and rest pain in one. The mean size of the vein specimen was 10.5 +/- 3.5 cm2. The mean duration of in vitro cell culture was 23.5 +/- 8.5 days. The mean density of seeding was 2.9 +/- 0.8 x 105 cells/cm2 prosthesis. No major complications were encountered during the immediate postoperative period (30 days). During follow-up two patients with patent bypasses died of intercurrent causes at 2 and 36 months, respectively, one patient had an abscess in the femoral triangle that required removal of the prosthesis (75 days), and three patients presented with bypass failure (2 occlusions and 1 thromboembolic complication) at 3, 10, and 53 months, respectively. Mean follow-up in the 20 patients surviving at 3 months was 42 +/- 15 months. Cumulative primary patency (Kaplan-Meier analysis) was 95% (+/- 10) at 3 months, 89% (+/- 13) at 10 and 48 months, and 67% (+/- 39) at 53 and 76 months. The two-stage seeding technique described herein was feasible in 69% of patients not requiring emergency reconstruction and did not increase perioperative morbidity and mortality. Bypass patency in patients who underwent above-knee femoropopliteal bypass for intermittent claudication was promising.

In vitro inhibition of RecA-mediated homologous pairing by UmuD'C proteins

The process of SOS mutagenesis in Escherichia coli requires: i) the replisome enzymes; ii) RecA protein; and iii) the formation of the UmuD'C protein complex which appears to help the replisome to resume DNA synthesis across a lesion. It has recently been shown that the UmuD'C complex, if overproduced, inhibits recombinational repair of a UV-damaged plasmid DNA as well as homologous recombination in an Hfr x F- cross. Since UmuD'C proteins might inhibit an early recombination step by interacting with a RecA nucleo-protein filament, we checked whether UmuD'C proteins will inhibit RecA promoted homologous pairing in vitro. We tested the inhibitory action of UmuD'C proteins in a crude bacterial extract containing possible cofactors such as chaperone proteins that ensure the proper folding of UmuC and the assembly of the UmuD'C complex in vivo. We used a novel recombination assay in which RecA protein promotes the formation of a stable plectonemic joint between a circular single-stranded DNA immobilized onto a membrane and an incoming homologous linear duplex DNA. Under these conditions we show that UmuD'C proteins inhibit the formation of joint molecules.

Characterization of Reca Mediated homologous pairing on nitrocellulose membrane

Reactions between a single-stranded DNA (ssDNA) and a double-stranded DNA (dsDNA) provide an efficient model to study RecA promoted homologous recombination. We have devised an assay in which the ssDNA is first bound to a nitrocellulose membrane. RecA protein is loaded on this membrane (loading step) which is then incubated with a labelled homologous dsDNA (incubation step). Since this assay can be used for study of mutant RecA proteins or RecA-like activities in crude extracts from other organisms, we have characterized the reaction promoted on the membrane. Under these new conditions, the reaction keeps the main characteristics observed with classical assays performed in solution: increasing NaCl concentration destabilized the RecA-DNA complex, ATP gamma S was required for formation of stable RecA-DNA complex, initiation of the reaction exhibits the same polarity as in classical assays, a complete strand exchange with a 44 bp long duplex oligonucleotide has been recorded under our conditions. Moreover, our results indicate that the binding of RecA protein itself to the nitrocellulose membrane did not impair its ability to promote homologous pairing. Pairing reactions involving long dsDNA (6407 bp) were more efficient with hydrolysable ATP than with ATP gamma S only when the ssDNA was bound to the membrane. Furthermore, ATP hydrolysis was not required when using short dsDNA (44 bp). These results constitute experimental support for a new role for the ATPase activity of RecA protein: the energy produced could favor the initiation of RecA mediated recombination involving long stretches of DNA which have restricted freedom to rotation.

Predictive value of apolipoprotein E genotyping in Alzheimer's disease: results of an autopsy series and an analysis of several combined studies

Apoliprotein E (apoE) is associated with Alzheimer's neurofibrillary tangles and beta-amyloid protein in senile plaques. Recent studies have shown an increased frequency of the epsilon 4 allele of the apoE gene in familial and sporadic cases of Alzheimer's disease (AD). In the present case control study, we have determined the apoE genotype by allele-specific extension of 113 postmortem cases of sporadic AD and 77 control brains shown to be free of AD neuropathological features and then calculated the frequency of the various allelic forms of apoE (epsilon 2, epsilon 3, epsilon 4). The odds ratio associating epsilon 4 with AD was 15.5 (95% confidence interval [CI] 6.2-38.5), and the population attributable risk was 0.53. We have also combined the results of our study and several others to calculate these same parameters in a larger population (570 controls and 961 AD subjects); the odds ratio for this larger group was 6.2 (95% CI 4.9-7.8) and the population attributable risk was 0.57. These results further substantiate and strengthen the association between the epsilon 4 allele of apoE gene and AD. We have also used these results to investigate the usefulness of the determination of epsilon 4 carrier status in the diagnosis of AD.