Significance of the reductase-dependent pathway for the beta-oxidation of unsaturated fatty acids with odd-numbered double bonds. Mitochondrial metabolism of 2-trans-5-cis-octadienoyl-CoA.

The beta-oxidation of unsaturated fatty acids with odd-numbered double bonds proceeds by reduction of the double bond (reductase-dependent pathway) in addition to the well established isomerization of the double bond (isomerase-dependent pathway). The metabolic significance of the reductase-dependent pathway was assessed with 2-trans-5-cis-octadienoyl-CoA (2,5-octadienoyl-CoA) and its products, all of which are metabolites of alpha-linolenic acid. A kinetic evaluation of beta-oxidation enzymes revealed that the presence of a 5-cis double bond in the substrate most adversely affected the activity of 3-ketoacyl-CoA thiolase although not enough to become rate-limiting. Concentration-dependent and time-dependent measurements indicated that most (80%) of 2,5-octadienoyl-CoA is metabolized via the isomerase-dependent pathway. The reason for the greater flux through the isomerase-dependent pathway is the higher activity of L-3-hydroxyacyl-CoA dehydrogenase as compared with Delta3,Delta2-enoyl-CoA isomerase. These two enzymes catalyze the rate-limiting steps in the isomerase-dependent and reductase-dependent pathways, respectively. Once 2,5-octadienoyl-CoA is converted to 3,5-octadienoyl-CoA (perhaps fortuitously because of the presence of Delta3,Delta2-enoyl-CoA isomerase), the only effective route for its degradation is via the reductase-dependent pathway. It is concluded that the reductase-dependent pathway assures the degradation of 3,5-dienoyl-CoA intermediates, thereby preventing the depletion of free coenzyme A and a likely impairment of mitochondrial oxidative function.

Peroxisomes contain delta 3,5,delta 2,4-dienoyl-CoA isomerase and thus possess all enzymes required for the beta-oxidation of unsaturated fatty acids by a novel reductase-dependent pathway.

The presence of delta 3,5,delta 2,4-dienoyl-CoA isomerase in peroxisomes was demonstrated by determining the subcellular distribution of this enzyme in rat liver. The peroxisomal and mitochondrial forms of the isomerase exhibit similar chain length specificities and they are homologous as indicated by the recognition of the peroxisomal 66-kDa enzyme by an antiserum raised against the mitochondrial 32-kDa isomerase. This report demonstrates that peroxisomes contain all enzymes required for the beta oxidation of unsaturated fatty acids with odd-numbered double bonds by a novel pathway in which double bonds are reductively removed by the NADPH-dependent 2,4-dienoyl-CoA reductase.

Spectrophotometric assay of 2,4-dienoyl coenzyme A reductase with 5-phenyl-2,4-pentadienoyl-coenzyme A as substrate.

The spectrophotometric assay of 2,4-dienoyl coenzyme A (CoA) reductase (EC 1.1.1.34) was modified to improve the linearity and sensitivity of this method. 5-Phenyl-2,4-pentadienoyl-CoA, which has an absorbance maximum at 340 nm with an extinction coefficient of 44,300 M-1 cm-1, was synthesized and used as substrate. This compound is reduced by nicotinamide adenine dinucleotide phosphate (NADPH)-dependent 2,4-dienoyl-CoA reductase to 5-phenyl-3-pentenoyl-CoA. When a tissue homogenate serves as an enzyme source, the product is further metabolized by delta 3, delta 2-enoyl-CoA isomerase (EC 5.3.3.8) to 5-phenyl-2-pentenoyl-CoA, which is hydrated to 5-phenyl-3-hydroxypentanoyl-CoA by enoyl-CoA hydratase (EC 4.2.1.17). The modified assay method, which measures the decrease in absorbance at 340 nm due to the reduction of 5-phenyl-2,4-pentadienoyl-CoA and the oxidation of NADPH, is linear for a longer period of time and is twice as sensitive as the conventional assay with 2,4-decadienoyl-CoA as substrate.

Delta 3,5, delta 2,4-dienoyl-CoA isomerase from rat liver mitochondria. Purification and characterization of a new enzyme involved in the beta-oxidation of unsaturated fatty acids.

Mitochondrial delta 3,5, delta 2,4-dienoyl-CoA isomerase, which catalyzes the conversion of 3,5-octadienoyl-CoA to 2,4-octadienoyl-CoA, was purified from rat liver 370-fold at almost 30% yield by a six-step purification procedure. The final preparation appeared to be homogeneous as judged by gel electrophoresis. The molecular weights of the native enzyme and its subunit(s) were estimated to be 126,000 and 32,000, respectively. The purification of delta 3,5, delta 2,4-dienoyl-CoA isomerase completes the characterization of the enzymes functioning in the NADPH-dependent pathway for the beta-oxidation of unsaturated fatty acids with double bonds extending from odd-numbered carbon atoms. This novel pathway may not be operative in peroxisomes because delta 3,5, delta 2,4-dienoyl-CoA isomerase was only detected in mitochondria. Substrates of this pathway are 2,5-dienoyl-CoAs formed from 5-enoyl-CoAs by acyl-CoA dehydrogenase. Two sequential isomerization reactions catalyzed by delta 3, delta 2-enoyl-CoAs isomerase and delta 3,5, delta 2,4-dienoyl-CoA isomerase, respectively, convert 2,5-dienoyl-CoAs to 2,4-dienoyl-CoAs, which are reduced by NADPH-dependent 2,4-dienoyl-CoA reductase (EC 1.3.1.34) before reentering the beta-oxidation spiral.

Dynamic echography of the penis in the follow-up of impotent patients treated with intracavernous injections.

Dynamic echography of the penis (DEP) after pharmacological stimulation of erection has been designed to evaluate the albugineal wall thickness (AWT), the cavernosal appearance in the normal penis and corporeal changes in patients treated with intracavernous injections presenting with haematomata, hyperechoic images, prolonged erection and Peyronie's disease. DEP was performed in 973 patients who had had an average number of 89 (+/- 16) intracavernous injections for 16.7 +/- 11.7 months. A total of 1424 DEP examinations were performed. Transducer positioning, erectile condition, clinical recording and computer retrieval methods were adapted to gather ultrasonography data. The standard average AWTs recorded in patients free from Peyronie's disease and who were untreated were 0.11 cm at the septum, 0.17 and 0.15 cm at the dorsal root and the tip of the albuginea respectively, 0.14 cm ventrally and the diameter of the corpus cavernosum averaged 1.61 cm. Intracavernous therapy brought an increase in AWT of 15.38% to the septum, 11.76% and 10.53% to the dorsal tip and root respectively and 12.5% ventrally. Frequent haematomata induced greater increase, while prolonged erections did not. Patients with untreated Peyronie's disease were found to have greater AWT which decreased after treatment with intracavernosal injections. Before treatment abnormal penile hyperechoic images were found in 3.18% (intracavernous images) and 3.31% (albugineal nodules) of DEP, and in 7.09% and 7.54% respectively post-treatment.

Intracavernous self-injection of vasoactive drugs in the treatment of impotence: 8-year experience with 615 cases.

Of 615 patients with impotence of varying etiologies who were followed from 12 to 96 months after the institution of intracavernous self-injection therapy with vasoactive drugs (papaverine alone, papaverine and alpha-blockers, and Ceritine, a new multilevel acting drug) 87% (533 patients) returned for followup visits or were regularly contacted. Of these patients sexual activity was restored in 91%. The dropout rate was 11.25%. The 114 episodes of prolonged erections among 51 patients (4.57%) represented less than 3 per 1,000 of the 34,875 recorded injections. All patients were treated without complications. The percentage of patients suffering from nodules or permanent deformations was 2.8%. There were no cases of intracavernous fibrosis. The percentage of satisfied patients (satisfaction index 7 or greater) was 84.8%. Improvement in spontaneous erections during sexual intercourse was obtained in 65% of the cases: 15% no longer needed self-injections and 50% only used them occasionally while 35% remained entirely dependent.

[Impotence of vascular origin]. / Impuissance d'origine vasculaire.

Between 1977 and 1986, 3,500 patients were examined for the symptom of impotence; 1,250 of them received multidisciplinary investigation permitting the diagnosis of a pure organic or mixed disorder in 85% of cases, including 62% of vascular disease subdivided into arterial (40%) and venous (22%). For 1,062 patients, 1 or several of the following therapies were used: intracavernous infusion of vasoactive drugs (N = 725), auto-injections (N = 235), vascular surgery (N = 357) and prostheses (N = 23). The diagnostic approach, formerly analytical and making use of multiple non-invasive methods, such as nocturnal erection plethysmography (NPT) and invasive methods (artificial erection, arteriography) have been transformed by the use of pharmacological tests associated with visual sexual stimulation (VSS) which enable, together with Doppler velocimetric examination, simple screening of vascular impotence based on the study of 4 parameters: penile pressure index (PPI) when less than 0.91 is always a sign of an arterial problem, the severity of which is directly proportional to the lowering of this index and the association with maintenance insufficiency; the initial intracavernous flow rate (IICF) depends overall on the maintenance flow and the state of erectile tissue, resulting from pharmacological stimulation by a low dose of papaverine (8 mg); penile rigidity attained by the combined action of pharmacological and visual sexual stimulation, reflecting the functional erectile capacity; the duration of the rigidity thus obtained on stoppage of VSS indicating the capacity for maintenance of erection. In the event of suspicion of an isolated venous leak or in association with arterial problems, it is the artificial erection with cavernosography, carried out after pharmacological stimulation, which enables the severity of the leak to be assessed. The following specific investigations are carried out to investigate a specific associated etiology: electromyogram for neurological disorders, hormone assay for endocrine disorders and psychological study using the MMPI questionnaire (Multiphasic Minnesota Personality Inventory). One can thus distinguish several groups of patients suffering from vascular impotence depending on the degree of arterial involvement: minor (PPI between 0.75 and 0.9), moderate (PPI between 0.65 and 0.75) and severe (PPI less than 0.65); depending on the degree of venous leaking: absent (MI less than 0.3 and/or MF less than 25 ml/min), minor (MI between 0.3 and 0.5 and MF between 30 and 50 ml/min), moderate (MI between 0.5 and 75 ml/min) and severe (MI greater than 0.75 and/or MF greater than 75 ml/mn).(ABSTRACT TRUNCATED AT 400 WORDS)

[Experimental study of the secretory motor function of the facial nerve]. / Etude expérimentale des fonctions sécrétomotrices du nerf facial.

An experimental study was done on dogs after cutting or crushing the facial nerve centrally at the level of the geniculate ganglion and peripherally at the level of the stylomastoïd foramen. In cases of central lesion of the facial nerve: The histological and histochemical study, after two weeks, showed atrophic changes in the lacrimal, nasal and submandibular glands, with a decrease in the size and number of acini, an increase in the interlobular connective tissue and excess fat cells in the lacrimal glands. The biochemical study revealed a decrease in the amount of the secretions with an increase their content of protein, mucin and amylase in the paralysed side compared to the normal. In cases of peripheral of the facial nerve: No histological histochemical or biochemical changes were found.