[Relevance of anti-tissue transglutaminase antibodies in coeliac disease diagnosis]

Coeliac disease is precipitated upon exposure to the dietary wheat gluten. Definitive diagnosis relies on intestinal biopsy and regression of clinical and histological disorders with adherence to a gluten-free diet. Coeliac disease is usually associated with a malabsorption syndrome. However, both atypical and silent clinical forms have been recently described and prevalence of the disease may be under-estimated. Serological tests have been developed in order to select candidates for intestinal biopsy, but these biological parameters are not suitable for screening in the general population. Indeed, antigliadin IgG antibodies have a poor specificity. antigliadin IgA antibodies a poor sensitivity. The detection of antiendomysial IgA antibodies (EmA) by immunofluorescence, although considered as the "gold standard" of serological coeliac disease markers, could not be automated, depends on a subjective fluorescence display, and may be limited by the degree of training of the observer. In year 1997, tissue transglutaminase (tTg) has been identified as the main autoantigen recognized by EmA. On this basis, solid-phase enzyme-linked immunosorbent assays (Elisa) have been developed in order to potentially replace the EmA assay. Several commercial kits are now available but their diagnostic performances have not yet been compared. We selected 75 sera, including sera from 26 patients with coeliac disease in order to evaluate five commercial anti-tTG Elisa kits. For all patients, treated or not, detection of anti-tTG antibodies with four of the five tested kits correlates with EmA test. Kits using human tTG have the highest specificity, equivalent to the value of EMA test, and widely better than antigliadin antibodies. Anti-tTG Elisa kits using human tTG may be used as an alternative way to the EmA assay in the next future, and may supplant IgA anti-gliadin antibodies for coeliac disease screening.

Effect of nonsteroidal anti-inflammatory agents and finasteride on prostate cancer risk

PURPOSE

We examine the relationship of nonsteroidal anti-inflammatory drugs and finasteride on the risk of prostate cancer.

MATERIALS AND METHODS

Participants in this case control study using a prospective collection of data were drawn from consecutive patients who underwent prostate biopsy at 12 different departments of urology from January 1999 to June 2000. Medication use was assessed by self-questionnaire as well as questions about dietary and lifestyle factors that might be relevant for prostate cancer risk.

RESULTS

The study included 639 patients with prostate cancer and 659 cancer-free controls. Univariate analysis showed no significant impact of aspirin and finasteride on prostate cancer risk while the nonaspirin nonsteroidal anti-inflammatory drug users had a lower risk (OR 0.80, 95% CI 0.64-0.99). After adjusting for potential confounders, the protective effect of nonaspirin nonsteroidal anti-inflammatory drugs was no longer significant (OR, 0.84, 95% CI 0.66-1.07), while finasteride showed a significant protective effect (OR 0.58, 95% CI 0.37-0.92).

CONCLUSIONS

The results suggest that finasteride could have a chemopreventive role in prostate cancer. While aspirin did not show any impact on prostate cancer risk, the role of nonaspirin nonsteroidal anti-inflammatory drugs warrants further studies.

Effect of nonsteroidal anti-inflammatory agents and finasteride on prostate cancer risk

PURPOSE

We examine the relationship of nonsteroidal anti-inflammatory drugs and finasteride on the risk of prostate cancer.

MATERIALS AND METHODS

Participants in this case control study using a prospective collection of data were drawn from consecutive patients who underwent prostate biopsy at 12 different departments of urology from January 1999 to June 2000. Medication use was assessed by self-questionnaire as well as questions about dietary and lifestyle factors that might be relevant for prostate cancer risk.

RESULTS

The study included 639 patients with prostate cancer and 659 cancer-free controls. Univariate analysis showed no significant impact of aspirin and finasteride on prostate cancer risk while the nonaspirin nonsteroidal anti-inflammatory drug users had a lower risk (OR 0.80, 95% CI 0.64-0.99). After adjusting for potential confounders, the protective effect of nonaspirin nonsteroidal anti-inflammatory drugs was no longer significant (OR, 0.84, 95% CI 0.66-1.07), while finasteride showed a significant protective effect (OR 0.58, 95% CI 0.37-0.92).

CONCLUSIONS

The results suggest that finasteride could have a chemopreventive role in prostate cancer. While aspirin did not show any impact on prostate cancer risk, the role of nonaspirin nonsteroidal anti-inflammatory drugs warrants further studies.

Initiation of HAART in drug-naive HIV type 1 patients prevents viral breakthrough for a median period of 35.5 months in 60% of the patients

The introduction of potent combinations of antiviral drugs is a major breakthrough in the treatment of HIV. We investigated the long-term virologic outcome and the development of resistance after initiating highly active antiretroviral therapy (HAART) in drug-naive patients in daily clinical practice. Twenty-five treatment-naive HIV-1 patients were started on HAART. Fifteen patients responded with a drop in viral load below the limit of detection during 35.5 (interquartile range: 7) months of therapy. In 6 of 10 patients with virologic failure, virus with resistance-related mutations against the received drugs emerged. Compared with responders (R), nonresponding (NR) patients were in a later disease stage at therapy start (p = 0.0089) with lower CD4 cell counts at baseline (p = 0.040), and a lower proportion of nonresponders showed protease inhibitor (PI) levels above C(min) (p = 0.049). More NR patients showed secondary PI mutations at baseline (p = 0.079), and the CCR2-64I coreceptor polymorphism was absent among NR patients, compared with 38.5% of R patients displaying CCR2-64I (p = 0.053), although the differences were not significant. In conclusion, starting HAART in antiretroviral drug-naive HIV-infected patients followed in daily clinical practice prevented viral breakthrough for up to 44 months in 60% of the patients. Virologic failure was associated with the development of resistance-related mutations, a later stage of disease at start of therapy and lower PI drug levels.

Determination of mitochondrial reactive oxygen species: methodological aspects

The generation of Reactive Oxygen Species (ROS) as by-products in mitochondria Electron Transport Chain (ETC) has long been admitted as the cost of aerobic energy metabolism with oxidative damages as consequence. The purpose of this methodological review is to present some of the most widespread methods of ROS generation and to underline the limitations as well as some problems, identified with some experiments as examples, in the interpretation of such results. There is now no doubt that besides their pejorative role, ROS are involved in a variety of cellular processes for the continuous adaptation of the cell to its environment. Because ROS metabolism is a complex area (low production, instability of species, efficient antioxidant defense system, several places of production...) bias, variances and limitations in ROS measurements must be recognized in order to avoid artefactual conclusions, and especially to improve our understanding of physiological and pathophysiological mechanisms of such phenomenon.

[Standards, options, and recommendation for external radiotherapy of prostatic cancer: evaluation of the effect of dosage]

CONTEXT

The "Standards, Options and Recommendations" (SOR) collaborative project was initiated in 1993 by the Federation of the French Cancer Centres (FNCLCC), with the 20 French Regional Cancer Centres, several French public university and general hospitals, as well as private clinics and medical speciality societies. Its main objective is the development of serviceable clinical practice guidelines in order to improve the quality of health care and the outcome of cancer patients. The methodology is based on a literature review, followed by critical appraisal by a multidisciplinary group of experts. Draft guidelines are produced, then validated by specialists in cancer care delivery.

OBJECTIVES

Produce clinical practice guidelines for the radiotherapy of prostate cancer using the methodology developed by the Standards, Options and Recommendations project.

METHODS

The FNCLCC and the French Urology Association (AFU) designated the multidisciplinary group of experts. Available data were collected by a search of Medline and lists selected by experts in the group. A first draft of the guidelines was written, they validated by independent reviewers.

RESULTS

The main recommendations are: 1/ a minimal dose of 70 Gy must be used, whatever the prognostic factors; 2/ it appeared that patients with favourable prognostic indicators (stage T1-2, PSA < or = 10 micrograms/L and Gleason score < or = 6) do not benefit from a dose escalation effect for doses over 70-74 Gy; 3/ patients with intermediate prognosis are the ones who benefit most from the dose escalation effect over 74 Gy, provided they receive exclusive radiation therapy; 4/ whenever possible, patients should be included in controlled trials designed to assess the effects of dose escalation and hormonotherapy.

Mitochondrial respiratory chain adjustment to cellular energy demand

Because adaptation to physiological changes in cellular energy demand is a crucial imperative for life, mitochondrial oxidative phosphorylation is tightly controlled by ATP consumption. Nevertheless, the mechanisms permitting such large variations in ATP synthesis capacity, as well as the consequence on the overall efficiency of oxidative phosphorylation, are not known. By investigating several physiological models in vivo in rats (hyper- and hypothyroidism, polyunsaturated fatty acid deficiency, and chronic ethanol intoxication) we found that the increase in hepatocyte respiration (from 9.8 to 22.7 nmol of O(2)/min/mg dry cells) was tightly correlated with total mitochondrial cytochrome content, expressed both per mg dry cells or per mg mitochondrial protein. Moreover, this increase in total cytochrome content was accompanied by an increase in the respective proportion of cytochrome oxidase; while total cytochrome content increased 2-fold (from 0.341 +/- 0.021 to 0.821 +/- 0.024 nmol/mg protein), cytochrome oxidase increased 10-fold (from 0.020 +/- 0.002 to 0.224 +/- 0.006 nmol/mg protein). This modification was associated with a decrease in the overall efficiency of the respiratory chain. Since cytochrome oxidase is well recognized for slippage between redox reactions and proton pumping, we suggest that this dramatic increase in cytochrome oxidase is responsible for the decrease in the overall efficiency of respiratory chain and, in turn, of ATP synthesis yield, linked to the adaptive increase in oxidative phosphorylation capacity.

[Standards, Options, and Recommendations for brachytherapy in patients with prostate cancer: efficacy and toxicity]

CONTEXT

The "Standards, Options and Recommendations" (SOR) collaborative project was initiated in 1993 by the Federation of the French Cancer Centres (FNCLCC), with the 20 French Regional Cancer Centres, several French public university and general hospitals, as well as private clinics and medical specialty societies. Its main objective is the development of serviceable clinical practice guidelines in order to improve the quality of health care and the outcome of cancer patients. The methodology is based on a literature review, followed by a critical appraisal by a multidisciplinary group of experts. Draft guidelines are produced, then validated by specialists in cancer care delivery.

OBJECTIVES

Produce clinical practice guidelines for the brachytherapy of prostate cancer using the methodology developed by the Standards, Options and Recommendations project.

METHODS

The FNCLCC and the French Urology Association (AFU) first designated the multidisciplinary group of experts. Available data were collected by a search of Medline and lists selected by experts in the group. A first draft of the guidelines was written, they validated by independent reviewers.

RESULTS

The main recommendations are: 1/Brachytherapy with permanent seeds alone is a possible curative treatment for prostate cancer patients with the following prognosis factors: tumour stage T1 or T2a (TNM 1992), Gleason score < or = 6 and PSA < 10 micrograms/L. 2/Combined treatment with brachytherapy and hormonal therapy could be more efficient than brachytherapy alone for prostate cancer patients with Gleason score > 7 and/or PSA > 10.3/Combination of brachytherapy and external beam radiation therapy can be proposed to prostate cancer patients with intermediate prognosis. 4/Before and after seed implantation, risks of infection must be prevented by appropriate antibiotic therapy (recommendation). 5/Brachytherapy must not be performed within 2 months of transurethral prostate resection. 6/The height of the urethra receiving more than 200% of the prescribed dose must be reported. The portion of the rectum receiving 100 and 120% of the prescribed dose must be limited to 10 and 5 mm length, respectively.

Genotypic correlates of resistance to HIV-1 protease inhibitors on longitudinal data: the role of secondary mutations

Direct sequencing of the pol gene was assessed retrospectively with protease inhibitor susceptibility in a longitudinal study. A total of 134 samples from 26 patients were analysed at regular intervals up to 2 years. Patients were included in virological failure despite indinavir, ritonavir or saquinavir based triple-drug therapy. Both the type and number of certain secondary protease mutations modulated the effect of primary mutations on phenotypic resistance. This was notably applicable to L101/V, and to lesser extents to A711V/T. However, combinations of primary mutations, including 154V could predict resistance to the drug used and nelfinavir in more than 80%. In contrast, in vitro cross-resistance to amprenavir was rarely encountered. In addition, there was a relationship between a higher number of key mutations and poorer virological and clinical outcomes, respectively, from 6 and 3 months on. The key mutations were the protease mutations independently conferring phenotypic resistance and/or the reverse transcriptase mutations predicting treatment outcome. This relationship was independent from drug history, viral load and CD4 cell count measurements. In summary, even on a small sample size, sequence-based genotyping seems to be a good prognostic marker when performed longitudinally. In the context of primary resistance mutations, including additional secondary mutations, it may be useful in the prediction of phenotypic and clinical resistance. This should be assessed to optimize treatment monitoring before emergence of broadly cross-resistant virus.

Rotenone inhibits the mitochondrial permeability transition-induced cell death in U937 and KB cells

The permeability transition pore (PTP) is a mitochondrial inner membrane Ca(2+)-sensitive channel that plays a key role in different models of cell death. Because functional links between the PTP and the respiratory chain complex I have been reported, we have investigated the effects of rotenone on PTP regulation in U937 and KB cells. We show that rotenone was more potent than cyclosporin A at inhibiting Ca(2+)-induced PTP opening in digitonin-permeabilized cells energized with succinate. Consistent with PTP regulation by electron flux through complex I, the effect of rotenone persisted after oxidation of pyridine nucleotides by duroquinone. tert-butyl hydroperoxide induced PTP opening in intact cells (as shown by mitochondrial permeabilization to calcein and cobalt), as well as cytochrome c release and cell death. All these events were prevented by rotenone or cyclosporin A. These data demonstrate that respiratory chain complex I plays a key role in PTP regulation in vivo and confirm the importance of PTP opening in the commitment to cell death.

Evaluation of two commercial kits for the detection of genotypic drug resistance on a panel of HIV type 1 subtypes A through J

We compared the two commercially available sequencing kits for HIV-1 drug resistance testing, the ViroSeq Genotyping System (Applied Biosystems, Foster City, CA, U.S.A.) and the TRUGENE HIV-1 Genotyping Kit (Visible Genetics, Inc., Toronto, Ontario, Canada), with our in-house genotyping system. Fifteen viral isolates from African patients (6 treated and 9 untreated) covering a panel of HIV-1 subtypes A through J and 7 plasma samples from Belgian and African patients (2 treated and 5 untreated) were tested. All the samples could be amplified and sequenced by the three systems; however, for all systems, alternative amplification/sequencing primers had to be used for some samples belonging to subtype B as well as to other subtypes. The consensus sequence was partially derived from only one strand for the in-house system and for the ViroSeq Genotyping System. The TRUGENE HIV-1 Genotyping Kit scored the highest number of ambiguities, followed by the ViroSeq Genotyping System and the in-house system. For 11 samples, these differences in reporting mixtures affected 14 resistance-related positions, which altered the interpretation toward protease inhibitors for 2 samples when using version 1.2 RetroGram software (Virology Networks, Utrecht, The Netherlands). All three systems were able to sequence diluted samples with a viral load down to 10 3 or 10 4 RNA copies/ml. Our data therefore suggest that the performance of amplification and sequencing primers must be improved to allow fast and reliable resistance testing for all HIV-1 subtypes.

[Systematic conservative surgery for kidney cancer smaller than 4 cm: multicenter study]

OBJECTIVE

To evaluate tumour control and morbidity of systematic conservative surgery for patients with a renal cancer < or = 4 cm.

MATERIALS AND METHODS

A retrospective multicentre study was performed in 73 patients undergoing systematic conservative surgery for renal cancer < or = 4 cm. The mean age of the patients was 55.8 years (range: 19-82). The mean diameter of the tumour was 2.8 cm +/- 0.9. Tumour stage was pT1 in 97% of cases and pT3a in 3% of cases. The mean follow-up was 46.2 months (range: 12-138).

RESULTS

The postoperative morbidity was 11%, including urinary fistulas in 5 cases and haemorrhage in 3 cases. No patient has developed local recurrence. One patient died from metastases. The 5-year recurrence-free survival was 97.4%.

CONCLUSION

Systematic partial nephrectomy has a low morbidity in patients with a renal cancer less than 4 cm. It ensures satisfactory medium-term tumour control. However, only long-term follow-up can establish the place of systematic partial nephrectomy in the treatment of renal cancer.

Role of substrates in the regulation of mitochondrial function in situ

Investigations of mitochondrial oxidative phosphorylation have been mainly carried out in isolated mitochondria, where the experimental conditions can be precisely set. However, in intact living systems oxidative phosphorylation takes place in a complex environment, whose experimental dissection is a major challenge. It has long been recognized that the efficiency of oxidative phosphorylation depends on the nature of the respiratory substrates, which feed electrons to the respiratory chain at different levels. Yet, the role of substrates in determining mitochondrial function and their response to energetic stress has been largely overlooked. Here we review recent work showing that the nature of the energetic substrates profoundly affects the mitochondrial responses to manipulations of pathophysiological relevance, such as uncoupling and opening of the permeability transition pore (PTP). Uncoupling of intact hepatocytes caused very different metabolic effects depending on whether carbohydrates or lipids were the energy source. With dihydroxyacetone as the substrate dinitrophenol caused a collapse of the mitochondrial membrane potential and of the ATP/ADP ratio, while the respiratory rate was increased only transiently. With octanoate as the substrate, on the other hand, dinitrophenol caused a dramatic stimulation of the respiratory rate, while the mitochondrial membrane potential and ATP/ADP ratio were affected only marginally. We then review results indicating that the activity of complex I directly regulates the PTP, a finding that emphasizes the importance of the respiratory substrates in PTP regulation.

Glucose 6-phosphate hydrolysis is activated by glucagon in a low temperature-sensitive manner

Glucagon affects liver glucose metabolism mainly by activating glycogen breakdown and by inhibiting pyruvate kinase, whereas a possible effect on glucose-6-phosphatase has also been suggested. Although such a target is of physiological importance for liver glucose production it was never proven. By using a model of liver cells, perifused with dihydroxyacetone, we show here that the acute stimulation of gluconeogenesis by glucagon (10(-7) m) was not related to the significant inhibition of pyruvate kinase but to a dramatic activation of the hydrolysis of glucose 6-phosphate. We failed to find an acute change in glucose-6-phosphatase activity by glucagon, but the increase in glucose 6-phosphate hydrolysis was abolished at 21 degrees C; conversely the effect on pyruvate kinase was not affected by temperature. The activation of glucose 6-phosphate hydrolysis by glucagon was confirmed in vivo, in postabsorptive rats receiving a constant infusion of glucagon, by the combination of a 2-fold increase in hepatic glucose production and a 60% decrease in liver glucose 6-phosphate concentration. Besides the description of a novel effect of glucagon on glucose 6-phosphate hydrolysis by a temperature-sensitive mechanism, this finding could represent an important breakthrough in the understanding of type II diabetes, because glucose 6-phosphate is proposed to be a key molecule in the transcriptional effect of glucose.

The mitochondrial consequences of uncoupling intact cells depend on the nature of the exogenous substrate

In isolated mitochondria the consequences of oxidative phosphorylation uncoupling are well defined, whereas in intact cells various effects have been described. Uncoupling liver cells with 2,4-dinitrophenol (DNP) in the presence of dihydroxyacetone (DHA) and ethanol results in a marked decrease in mitochondrial transmembrane electrical potential (DeltaPsi), ATP/ADP ratios and gluconeogenesis (as an ATP-utilizing process), whereas the increased oxidation rate is limited and transient. Conversely, when DHA is associated with octanoate or proline, DNP addition results in a very large and sustained increase in oxidation rate, whereas the decreases in DeltaPsi, ATP/ADP ratios and gluconeogenesis are significantly less when compared with DHA and ethanol. Hence significant energy wastage (high oxidation rate) by uncoupling is achieved only with substrates that are directly oxidized in the mitochondrial matrix. Conversely in the presence of substrates that are first oxidized in the cytosol, uncoupling results in a profound decrease in mitochondrial DeltaPsi and ATP synthesis, whereas energy wastage is very limited.

Exogenous Mg-ATP induces a large inhibition of pyruvate kinase in intact rat hepatocytes

Mg-ATP infusion in vivo has been reported to be beneficial both to organ function and survival rate in various models of shock. Moreover, a large variety of metabolic effects has been shown to occur in several tissues due to purinergic receptor activation. In the present work we studied the effects of exogenous Mg-ATP in rat liver cells perifused with dihydroxyacetone to investigate simultaneously gluconeogenetic and glycolytic pathways. We found a significant effect on oxidative phosphorylation as characterized by a decrease in oxygen consumption rate and in the cellular ATP-to-ADP ratio associated with an increase in lactate-to-pyruvate ratio. In addition, exogenous Mg-ATP induced rapid and reversible inhibition of both gluconeogenesis and glycolysis. The main effect on gluconeogenesis was located at the level of the fructose cycle, whereas the decrease in glycolysis was due to a strong inhibition of pyruvate kinase. Although pyruvate kinase inhibition induced by exogenous Mg-ATP was allosteric when assessed in vitro after enzyme extraction, we found a large decrease in the apparent maximal velocity when kinetics were assessed in vivo in intact perifused hepatocytes. This newly described short-term regulation of pyruvate kinase occurs only in the intact cell and may open new potentials for the pharmacological regulation of pyruvate kinase in vivo.

[Ultra-rapid detoxification of opiate dependent patients: review of the literature, critiques and proposition for an experimental protocol]

Ultra-rapid opioid detoxification (UROD) is an increasingly popular technique for detoxifying patients addicted to opiates. This technique aims at reducing not only the duration but also the intensity of withdrawal by using general anesthesia coupled with a naloxone or naltrexone medication. In this paper the authors attempt to review the history of UROD and the logic of its procedure and results whilst also demonstrating its advantages and limits.

METHOD

The MEDLINE database was searched from 1966 to 2000 using the terms "ultra-rapid opioid detoxification, rapid opioid detoxification under anesthesia, naloxone, naltrexone, opioid-related disorders". Additional data sources included bibliographies in textbooks on substance abuse.

RESULTS

Nine studies identified in our search were analysed. The technique is based on a three-phases procedure. It consists of a medical and psychiatric selection of patients addicted to opiates, followed by the detoxification itself and finally a medical and psychosocial follow-up. A brief presentation is made of the theoretical aspects based on the use of a specific opioid receptor antagonist (naloxone and naltrexone). Only inpatients were included in the studies. The detoxification and anesthesia protocols varied. In every study all the subjects were completely detoxified. Only three studies included a control group and two used a randomized design. Three studies reported a follow-up beyond 30 days.

DISCUSSION

Although this technique constitutes a safe and effective solution for opiate addicted patients, there are criticisms to be made. The absence of an animal model prior to the study of a human model, the lack of comparison with other procedures, the limitation of available literature, the cost and the risks of this technique and the lack of long-term treatment outcomes obtained from rigorous clinical trials, all call for further assessments. A more rigorous protocol based on the main areas of criticism is proposed (presentation of the inclusion and exclusion criterias, description of the three preliminary interviews, presentation of the UROD technique itself and finally a detailled nine month follow-up).

CONCLUSION

Ultra-rapid opiate detoxification represents a potentially safe and effective treatment for opiate addicted patients but more rigorous research methods are needed to render this procedure entirely valid.

Variant human immunodeficiency virus type 1 proteases and response to combination therapy including a protease inhibitor

The objective of this observational study was to assess the genetic variability in the human immunodeficiency virus (HIV) protease gene from HIV type 1 (HIV-1)-positive (clade B), protease inhibitor-naïve patients and to evaluate its association with the subsequent effectiveness of a protease inhibitor-containing triple-drug regimen. The protease gene was sequenced from plasma-derived virus from 116 protease inhibitor-naïve patients. The virological response to a triple-drug regimen containing indinavir, ritonavir, or saquinavir was evaluated every 3 months for as long as 2 years (n = 40). A total of 36 different amino acid substitutions compared to the reference sequence (HIV-1 HXB2) were detected. No substitutions at the active site similar to the primary resistance mutations were found. The most frequent substitutions (prevalence, >10%) at baseline were located at codons 15, 13, 12, 62, 36, 64, 41, 35, 3, 93, 77, 63, and 37 (in ascending order of frequency). The mean number of polymorphisms was 4.2. A relatively poorer response to therapy was associated with a high number of baseline polymorphisms and, to a lesser extent, with the presence of I93L at baseline in comparison with the wild-type virus. A71V/T was slightly associated with a poorer response to first-line ritonavir-based therapy. In summary, within clade B viruses, protease gene natural polymorphisms are common. There is evidence suggesting that treatment response is associated with this genetic background, but most of the specific contributors could not be firmly identified. I93L, occurring in about 30% of untreated patients, may play a role, as A71V/T possibly does in ritonavir-treated patients.

Mitochondrial adaptation to in vivo polyunsaturated fatty acid deficiency: increase in phosphorylation efficiency

Polyunsaturated fatty acid (PUFA) deficiency affects respiratory rate both in isolated mitochondria and in hepatocytes, an effect that is normally ascribed to major changes in membrane composition causing, in turn, protonophoriclike effects. In this study, we have compared the properties of hepatocytes isolated from PUFA-deficient rats with those from control animals treated with concentrations of the protonophoric uncoupler 2,4-dinitrophenol (DNP). Despite identical respiratory rate and in situ mitochondrial membrane potential (delta psi), mitochondrial and cytosolic ATP/ADP-Pi ratios were significantly higher in PUFA-deficient cells than in control cells treated with DNP. We show that PUFA-deficient cells display an increase of phosphorylation efficiency, a higher mitochondrial ATP/ADP-Pi ratio being maintained despite the lower delta psi. This is achieved by (1) decreasing mitochondrial Pi accumulation, (2) increasing ATP synthase activity, and (3) by increasing the flux control coefficient of adenine nucleotide translocation. As a consequence, oxidative phosphorylation efficiency was only slightly affected in PUFA-deficient animals as compared to protonophoric uncoupling (DNP). Thus, the energy waste induced by PUFA deficiency on the processes that generate the proton motive force (pmf) is compensated in vivo by powerful adaptive mechanisms that act on the processes that use the pmf to synthesize ATP.

Comparison of DNA sequencing and a line probe assay for detection of human immunodeficiency virus type 1 drug resistance mutations in patients failing highly active antiretroviral therapy

The resistance of human immunodeficiency virus type 1 (HIV-1) to drugs is a major cause of antiretroviral treatment failure. We have compared direct sequencing to a line probe assay (LiPA) for the detection of drug resistance-related mutations in 197 clinical samples, and we have investigated the sequential appearance of mutations under drug pressure. For 26 patients with virological failure despite the use of two nucleoside analogues and one protease inhibitor (indinavir [n = 6], ritonavir [n = 10], and saquinavir [n = 10]), genotypic resistance assays were carried out retrospectively every 3 months for up to 2 years by using direct sequencing (TruGene; Visible Genetics) and a LiPA for detection of mutations in the reverse transcriptase (INNO-LiPA HIV-1 RT; Innogenetics) and the protease (INNO-LiPA HIV Protease, prototype version; Innogenetics) genes. Comparison of the results from both assays found rare major discrepancies (<1% of codons analyzed). INNO-LiPA detected more wild-type-mutant mixtures than sequencing but suffered from a high rate of codon hybridization failures for the reverse transcriptase. LiPA detected earlier and more frequently than sequencing the transient mixed virus population that contained I84V, which appears before V82A in the protease sequence. Mutations M461, G48V, and L90M were often transient and drug pressure related. In conclusion, direct sequencing and LiPAs give concordant results for most clinical isolates. LiPAs are more sensitive for the detection of mixed virus populations. Mutation I84V appears in minor populations in the early steps of the pathways of resistance to indinavir and ritonavir. The fact that some mutations can be found only transiently and in minor virus populations highlights the importance of a low detection limit for resistance assays.

[Prostatic biopsies: technical modalities and conditions of the test]

Histological examination of prostate biopsies is necessary for the diagnosis of prostate cancer. The technical modalities and examination conditions of prostate biopsies were evaluated in the light of a review of the literature and the conclusions are presented in the form of standards, options and recommendations.

STANDARDS

The standard or modified protocol of 6 sextant biopsies, applied as first-line investigation in all cases of stage T1c or T2 prostate cancer is a standard procedure and remains a reproducible, effective and well tolerated method for diagnosis and staging. Rectal preparation by enema and prophylactic antibiotics before the examination decrease the risk of infectious complications. In its usual modality used for the majority of patients, biopsies are performed as an outpatient procedure, with or without local anaesthesia, with ultrasound guidance via a transrectal approach using an 18 Gauge needle (pink colour code), mounted on an automatic biopsy gun and especially sampling the posterior and lateral zone. The patient must be given written information explaining the risks and management of possible complications following this examination.

OPTIONS

Local, regional or general anaesthesia may be necessary in a minority of cases, either in the context of a protocol of extensive systematized biopsies (more than 10 biopsies), or in the case of repeated examination, or when preferred by the patient. Modified extensive protocols (sextant plus posterolateral zones or sextant plus anterior zones) applied to all cases as first-line procedure is a useful option, particularly when: 1) a first series of biopsies was negative 2) PSA is < or = 10 ng/ml and digital rectal examination is normal (sextant plus posterolateral zones) 3) the prostate is larger than 50 cm3 (sextant plus anterior zones). The transperineal approach is less reliable for detection and staging, and is used when the transrectal approach is contraindicated. When curative treatment is not considered (life expectancy < 10 years, patient's choice, stage T3, T4), the number of biopsies can be decreased. Transurethral resection of the prostate is not recommended as first-line procedure for the diagnosis of prostate cancer.

RECOMMENDATIONS

Written information given to the patient during the visit prior to biopsy to explain the objectives, practical modalities and risks of prostate biopsies facilitates the patient's cooperation during the examination and increases its tolerance.