Improved reproducibility in preparing precision-cut liver tissue slices

More than 35 years ago double Nobel laureate Linus Carl Pauling published a powerful model of the molecular mechanism of general anesthesia, generally referred to as the hydrate-microcrystal (aqueous-phase) theory. This hypothesis, based on the molecular behavior of water molecules, did not receive serious attention during Pauling’s life time, when scientific tools for examining complex systems such as the brain were still in their infancy. The situation has since drastically changed, and, now, in the twenty first century, many scientific tools are available for examining different types of complex systems. The discovery of aquaporin-4, a subtype of water channel abundantly expressed in glial systems, further highlighted the concept that the dynamics of water molecules in the cerebral cortex play an important role in important physiological brain functions including consciousness and information processing.     

Innervation of the testicular interstitial tissue in reptiles

Summary In the tortoise Testudo graeca, the lizards Lacerta dugesi and Lacerta pityusensis, and the snake Natrix natrix, the innervation of the testicular interstitial tissue was studied by light and electron microscopy, the acetylcholinesterase (ache) technique, the Falck-Hillarp method for the detection of catecholamines, and the application of 6-hydroxydopamine. The intertubular spaces of the reptilian testes studied contain adrenergic nerve fibers the amount and distribution of which varies considerably both in various species and in various stages of the reproduction cycle. Nerve fibers do not enter the seminiferous epithelium. Fluorescence microscopy of the lizard testis reveals catecholaminergic varicosities which are mainly arranged around blood vessels, but do not show obvious connexions to Leydig cells. Ache-positive fibers are equally distributed in lizard testes surrounding each seminiferous tubule. In Natrix natrix ache-positive fibers are irregularly spread among groups of tubules, without showing a definite relation to Leydig cells either. By electron microscopy bundles of unmyelinated axons and axon terminals can be more easily detected in the testes of immature animals than in adult. Terminals of nerve fibers containing small (400–500 Å in diameter) and large (800–1400 Å) dense-cored vesicles and sometimes small clear vesicles establish contacts with Leydig cells. Three types of contact are described. 1. Contacts par distance at a distance of about 2000 Å and basal lamina interposed; 2. membranous contacts having a 200 Å gap only between axolemma and Leydig cell plasmalemma; 3. invaginations of terminals into Leydig cell perikarya. The latter may exhibit surface specialisations, which strongly resemble postsynaptic membrane thickenings. Experiments using 6-hydroxydopamine underline the adrenergic character of testicular nerve fibers, which can be regarded as another example of non-cholinergic, ache-positive neurons. In the testis of the immature tortoise profiles of axons occur which probably represent purinergic, ache-positive neurons.Supported by a grant from the Deutsche Forschungsgemeinschaft (Un 34/1).I am much indebted to Mrs. R. Sprang for her skillfull technical assistance.     

Morphometric studies on mink testicular tissue

The mink, a seasonal breeder of great economic importance, shows a high incidence of male infertility. This problem has forced investigators to find methods of assaying male mink infertility. In this study, morphometric studies have been performed on testicular tissue of a total of 31 males eliminated from breeding after testicular palpation, sperm test, and estimation of serum testosterone concentrations. Males having low sperm quality or disturbed testicular development (n=24) had significantly (p<0.01) lower numbers of spermatocytes, spermatids, and freefloating luminal spermatozoa. compared with males with good sperm quality (n=7). No differences were found in the numbers of spermatogonia, Sertoli, and Leydig cells. Other morphometric parameters such as mean diameter, mean area, mean volume, percentage of area, and surface area per volume of nuclei are also presented for each cell type in the testis. It may be concluded that the sperm test is best suited for assessing fertility in mink. Severe disturbances in testicular development can be detected by testicular palpation and serum testosterone measurements.     

Branched-chain amino acid aminotransferase in mouse testicular tissue

Branched-chain amino acid aminotransferase (L-leucine:2-oxoglutarate aminotransferase, EC 2.6.1.6) activity was determined in several tissues of the mouse. Testis homogenates presented a specific activity very close to that of heart extracts which were the most active. Enzyme activity was detectable in testes from 5-day-old mice and increased steadily during development to reach a maximum at the 20th day of life. The transaminase was present in the cytosol of testicular homogenates and also associated, probably in the matrix, with a special type of mitochondria present in spermatozoa and gametogenic cells. The enzyme from testis is active against the three branched-chain amino acids and catalyses the reaction in both directions. Highest activity and lowest Km were obtained with L-leucine. Activity with L-valine was the lowest. The enzyme from the mitochondrial fraction showed identical properties to that from the soluble phase. The possible participation of this aminotransferase in a shuttle system transferring reducing equivalents from cytoplasm to mitochondria is postulated.     

The regenerative capacity of testicular interstitial tissue

Summary A single intraperitoneal injection of ethane dimethanesulphonate (EDS) destroys all Leydig cells in the adult rat testis but 1–2 weeks later new foetal-type Leydig cells begin to regenerate within the interstitial tissue. A further EDS treatment at 4 weeks failed to kill the new population of foetal-type Leydig cells. Between 10–20 weeks, the new Leydig cells exhibited the characteristics of adult-type Leydig cells. These cells responded to another EDS treatment by exhibiting a second phase of complete degeneration followed by regeneration of a foetal-type and subsequently an adult-type cell population. The results indicate that the testis retains the ability to replenish its supply of Leydig cells despite successive phases of total degradation of Leydig cells.     

Steroid metabolism in testicular tissue of genetic mutant mice

The conversion of testosterone and progesterone to other products was studied in testes of normal BALB/C mice, testieular, feminized (Tfm o⁺) and testicular feminized mice carrying the protective (o^hv) gene. The formation of testosterone from progesterone was 11 ± 1.3% in normal mice, 2.20 ± 0.8% in (Tfm o^hv) and 0.8 ± 0.2% in (Tfm o⁺ mice. With androstenedione as substrate, both (Tfm o⁺) and (Tfm o^hv) synthesized testosterone equally well. Testicular progesterone metabolism was also compared between normal and sex reversed (sxr) mice. The data suggested that the 17β hydroxysteroid dehydrogenase was more active in normal mice whereas the testes from the sex reversed (Tfm o^hv) gave higher conversions to androstenedione. Some conversion to dihydrotestosterone and androstanediol was found in all the testicular incubations.     

The protective role of erdosteine on testicular tissue after testicular torsion and detorsion

Testicular torsion and detorsion are important clinical problems for infertile man and oxidative stress may have a role in this clinical situation. The aim of this study was to investigate the protective role of erdosteine, an antioxidant, on unilateral testicular reperfusion injury in rats. The rats were divided into four groups including seven rats in each group: control, torsion, torsion/detorsion and torsion/detorsion+erdosteine. Rats, except the sham operation group, were subjected to left unilateral torsion (720^∘ rotation in the clockwise direction) without including the epididymis. The experiments were finished after sham operation time for control, 120 min torsion for torsion group and 120 min torsion and 240 min detorsion for torsion/detorsion groups. Bilateral orchiectomy was performed for all groups of rats. The ipsilateral and controlateral testis were divided into two pieces to analyse biochemical parameters and to investigate the light microscopic view. Malondialdehyde level of ipsilateral testis was increased in torsion and torsion/detorsion groups in comparison with the other groups (p < 0.05). Erdosteine treatment ameliorated lipid peroxidation after torsion/detorsion in ipsilateral testis (p < 0.05). Also, xanthine oxidase activity of ipsilateral testis was increased in torsion/detorsion group in comparison with the others (p < 0.05). Nitric oxide (NO) level of ipsilateral testis was higher in all experimental groups than sham operated control group (p < 0.05). Also, NO level of torsion group was increased in comparison with detorsion groups (p < 0.05). Erdosteine treatment caused increased glutathione peroxidase activity in comparison with torsion and torsion/detorsion groups and catalase activity in comparison with the other groups in ipsilateral testis (p < 0.05). Superoxide dismutase activity of ipsilateral testis was higher in torsion/detorsion and torsion/detorsion+erdosteine groups than control and torsion groups (p < 0.05). The biochemical parameters were not affected in controlateral testis in all groups. Torsion, torsion/detorsion and torsion/detorsion+erdosteine groups showed ipsilateral testicular damage in the histological examination, but the specimens from torsion/detorsion had a significantly greater histological injury than those from the other groups (p < 0.05). Control rats showed normal seminiferous tubule morphology. Rats in torsion group had slight-to-moderate disruption of the seminiferous epithelium. Rats in torsion/detorsion group displayed moderate-to-severe disruption of the seminiferous epithelium. In all animals from torsion/detorsion+erdosteine group, the testicular tissues were affected with slight-to-moderate degenerative changes of the seminiferous epithelium. Administration of erdosteine resulted in a significantly reduced histological damage associated with torsion of the spermatic cord compared with torsion/detorsion. In all groups, the contralateral testes were histologically normal. In conclusion, the results clearly displayed that erdosteine treatment may have a protective role on testicular torsion/detorsion injury. (Mol Cell Biochem xxx: 193–199, 2005)