Protective effect of L-carnitine on testicular ischaemia-reperfusion injury in rats

Testicular torsion is a urological emergency referred to as 'acute scrotum', because inappropriate treatment can lead to male subfertility and infertility. A possible cause of testicular damage is the ischaemia-reperfusion (I/R) injury attributed to oxygen free radicals. L-carnitine, a vitamin-like antioxidant, plays a pivotal role in the maturation of spermatozoa within the reproductive tract. The aim of the present paper was to determine the protective effect of L-carnitine on testicular I/R-induced injury. Thirty-two male rats were divided into 4 groups (n = 8). Testicular torsion was created by rotating the right testis 720 degrees in a clockwise direction. Group 1: sham-operated control; group 2: ischaemia; group 3: I/R; group 4: ischaemia-L-carnitine treatment-reperfusion group. L-carnitine (500 mg kg(-1), intraperitoneally) was administered before 30 min of detorsion in Group 4. After torsion (5 h) and detorsion (5 h), bilateral orchidectomy was performed. The malondialdehyde (MDA) level was evaluated in testes. Histopathologically, Johnsen's spermatogenesis criteria and mean seminiferous tubule diameter (MSTD) measurements were used. Testicular MDA levels were higher in the torsion group compared to the sham-control group (p < 0.05). Detorsion (reperfusion) caused a further increase in MDA levels (p < 0.05). Pretreatment with L-carnitine prevented a further increase in MDA levels (p < 0.05). Histologically, torsion caused some separation among germinal cells in the seminiferous tubules, which became much more prominent in the I/R group but was attenuated with L-carnitine pretreatment. In conclusion, L-carnitine pretreatment may have a protective effect in experimental testicular torsion-detorsion model in rats by its well-known antioxidant potential.     

Impacts of calcium addition and different oil types and levels on in vitro rumen fermentation and digestibility

This in vitro study was designed to investigate the effects of calcium addition to substrates differing in source and level of oil on fermentation, gas production, and digestibility parameters. Substrates were made from basal mixtures containing three levels of calcium salt (0, 1, and 2% CaCl2) to contain three levels (3, 6, and 9%) of two types (sunflower and soy) of oil. After collecting from two Holstein bulls and mixing with buffer, rumen fluid was used to incubate the resulting 18 mixtures in duplicate. Ionizable calcium, pH and NH3-N concentration were measured during incubation. Gas production was measured at 6, 12, 24, and 48 h after incubation. Kinetics parameters of gas production and in vitro dry matter digestibility (IVDMD) were calculated from regression coefficients of an exponential equation and a linear equation, respectively. Data were analysed using 3-way ANOVA with repeated measure option in which the parameter time was a subplot. Oil type did not affect pH and ionizable calcium concentration. There were linear increases and decreases in pH and ionizable calcium concentration in response to increasing oil and calcium levels, respectively. However, with increasing oil levels there were no interactions between calcium addition and oil level on pH and ionizable calcium concentration. None of the treatments affected NH3-N concentration. The amount of gas produced from substrates containing sunflower oil was greater than soy oil (41.7 vs. 40.5 ml). Cumulative gas production and amount of gas production from insoluble but slowly fermentable portion of the supplemental mixtures linearly decreased and linearly increased as oil and calcium levels increased in the substrates, respectively. However, interactions of calcium addition and oil level on gas production and kinetics of gas production were lacking. Oil type did not affect IVDMD. Despite lacking main effects, interaction of calcium addition and oil level indicated that increasing calcium level alleviated depression in IVDMD resulting from increasing oil level. In conclusion, increasing oil level depressed, whereas calcium addition stimulated ruminal fermentation. Improvement in IVDMD may partially support that calcium addition alleviates the adverse effects of oil and that more calcium is needed when diets are supplemented with increasing amounts of oil.     

Isolation and characterization of a new type of aerobic,oxalic acid utilizing bacteria,and proposal of Oxalicibacterium flavum gen. nov., sp. nov

A mesophilic, aerobic oxalic acid utilizing yellow-pigmented bacterium has been isolated from litter of oxalate producing plants in the region of Izmir (Turkey). It is motile by means of 1-3 polar flagella. Optimal growth occurred between 25-30 degrees C at pH 6.9. The G+C content of DNA is 62-64 mol % (Tm). Based on its morphological and biochemical features the organism belongs to the genus Pseudomonas, but differs from all the previously described species. The taxonomic relationships among strains described as or previously tentatively assigned to the genus Pseudomonas were investigated using numerical classification, DNA base composition and DNA-DNA hybridization. 16S rDNA sequences were determined for the strain TA17. On the basis of 16S rDNA sequence comparisons, physiological and biochemical characteristics, it is proposed to classify TA17T in a new genus and species for which the name Oxalicibacterium flavum gen. nov., sp. nov. is proposed. The type strain is TA17T (= NEU98T, = LMG 21571T).     

Use of a Hemoglobin-Trapping Approach in the Determination of Nitric Oxide in In Vitro and In Vivo Systems

We describe methods for measuring the release of nitric oxide (NO) derived from organic nitrates in vitro, using triple wavelength and difference spectrophotometry in the presence and absence of concentric microdialysis probes. These methods are based on the ability of NO to oxidize oxyhemoglobin (OxyHb) to methemoglobin (MetHb) quantitatively in aqueous solution. Isosorbide dinitrate (ISDN), a thiol-dependent organic nitrate, increased MetHb concentration in 45 min from 2.47 ± 0.47 to 4.15 ± 0.12 M (p < 0.05) and decreased OxyHb concentration from 2.13 ± 0.35 to 0.33 ± 0.26 M (p < 0.05) at 37°C. At 27°C, the OxyHb concentration was not significantly altered (2.04 ± 0.23 to 1.60 ± 0.04 M) by ISDN, nor was the MetHb concentration (from 2.68 ± 0.50 to 2.59 ± 0.25 M). Sodium nitroprusside (SNP), a thiol-independent organic nitrate, increased MetHb concentrations in 30 min from 4.21 ± 0.26 to 6.00 ± 0.56 M (p < 0.05) at 37°C, and from 4.23 ± 0.39 to 5.90 ± 0.43 M (p < 0.01) at 27°C. SNP also decreased OxyHb concentrations in 30 min from 1.99 ± 0.32 to 0.13 ± 0.12 M (p < 0.01) at 37°C, and from 2.25 ± 0.31 to 0.13 ± 0.09 M (p < 0.01) at 27°C. Difference spectrophometry indicated that 0.25-5 mM SNP significantly increased NO production in a dose-dependent fashion. This hemoglobin-trapping technique was also useful in quantifying the concentrations of NO released from SNP in aqueous solution in vitro, using concentric microdialysis probes. The NO concentration following exposure to SNP was 530 ± 50 nM, as determined using the difference spectrophotometric technique. To demonstrate the applicability of this technique to in vivo microdialysis, we implanted concentric microdialysis probes into hippocampus and cerebellum of conscious and anesthetized rats. Baseline NO concentrations in hippocampus of conscious and anesthetized rats were 11 ± 2 nM and 23 ± 9 nM, respectively, while in the cerebellum NO concentrations were 28 ± 9 nM and 41 ± 20 nM, respectively. These results demonstrate that microdialysis using a novel hemoglobin-trapping technique possesses adequate sensitivity to measure the NO levels produced from organic nitrates in aqueous solutions, and further document the applicability of this approach to in vivo systems.     

Medical Students’ Opinions About the Commercialization of Healthcare: A Cross-Sectional Survey

There are serious concerns about the commercialization of healthcare and adoption of the business approach in medicine. As market dynamics endanger established professional values, healthcare workers face more complicated ethical dilemmas in their daily practice. The aim of this study was to investigate the willingness of medical students to accept the assertions of commercialized healthcare and the factors affecting their level of agreement, factors which could influence their moral stance when market demands conflict with professional values. A cross-sectional study was conducted in three medical schools in Turkey. The study population consisted of first-, third-, and sixth-year students, and 1,781 students participated in total. Students were asked to state if they agreed with the assertions of commercialized healthcare. Of all students, 87.2 per cent agreed with at least one of the assertions, and one-fifth (20.8 per cent) of them agreed with more than half of the assertions. First-year students significantly agreed more with some assertions than third- and sixth-year students. Being female, having mid-level family income, choosing medicine due to idealistic reasons, and being in the third or sixth years of medical study increased the probability of disagreement. Also, studying in a medical school that included integrated lectures on health policies, rights related to health, and health inequities, along with early field visits, increased the probability of disagreement. This study suggests that agreement with the assertions of commercialized healthcare might be prevalent among students at a considerable level. We argue that this level of agreement is not compatible with best practice in professional ethics and indicates the need for an educational intervention in order to have physicians who give priority to patients’ best interests in the face of market demands.     

Biological time-dependent difference in effect of peroxynitrite demonstrated by the mouse hot plate pain model

We previously demonstrated the rhythmic pattern of L-arginine/nitric oxide (NO)/cyclic guanosine monophosphate (cGMP) cascade in nociceptive processes. The coupled production of excess NO and superoxide leads to the formation of an unstable intermediate peroxynitrite, which is primarily responsible for NO-mediated toxicity. In the present study, we evaluated the biological time-dependent effects of exogenously administered peroxynitrite on nociceptive processes and peroxynitrite-induced changes in the analgesic effect of morphine using the mouse hot-plate pain model. Experiments were performed at four different times of day (1, 7, 13, and 19 hours after lights on, i.e., HALO) in mice of both sexes synchronized to a 12 h:12 h light-dark cycle. Animals were injected intraperitoneally (i.p.) with saline or 10 mg/kg morphine 30 min before and 0.001 mg/kg peroxynitrite 30 sec before hot-plate testing, respectively. The analgesic effect of morphine exhibited significant biological time-dependent differences in the thermally-induced algesia; whereas, administration of peroxynitrite alone exhibited either significant algesic or analgesic effect, depending on the circadian time of its injection. Concomitant administration of peroxynitrite and morphine reduced morphine-induced analgesia at three of the four different study time points. In conclusion, peroxynitrite displayed nociceptive and antinociceptive when administered alone according to the circadian time of treatment, while it diminished analgesic activity when administered in combination with morphine at certain biological times.     

Temporal Variation in Serum Nitrite Levels in Rats and Mice

Although considerable evidence implicates involvement of nitric oxide (NO) in circadian regulation, little is known about possible 24h variations in basal NO metabolism. In this study, daily variations in serum nitrite levels were studied in locally bred mice and rats during the months of September and October. The serum was separated from blood samples obtained at six different times of the day and night (lh, 5h, 9h, 13h, 17h, and 21h after lights off [HALO] from male albino mice and rats). As an index of in vivo NO generation, serum nitrite levels (determined by the diazotization method) in rats exhibited significant temporal fluctuation (unpaired Student t test), with the concentration highest at 5 HALO and 21 HALO and lowest at 9 HALO. No such temporal variation was detected in mice in these studies conducted on locally bred animals in the autumn. (Chwnobiology International, 16(4), 527-532, 1999)     

Description of Oxalicibacterium horti sp. nov. and Oxalicibacterium faecigallinarum sp. nov., new aerobic, yellow-pigmented, oxalotrophic bacteria

Three strains of aerobic, Gram-negative, rod-shaped, non-spore-forming, yellow-pigmented bacteria (OD1^T, YOx^T and NS13), which were isolated in previous studies by enrichment in a mineral medium with potassium oxalate as the sole carbon source, were characterized. On the basis of 16S rRNA gene sequence similarity, strains OD1^T, YOx^T and NS13 belong to the Betaproteobacteria , most closely related to Oxalicibacterium flavum TA17^T (97.2–99.7% sequence similarity). The major whole-cell fatty acids were C_16:0, C_16:1ω7c and C_17:0 cyclo. The results of DNA–DNA hybridization and physiological and biochemical tests allowed genotypic and phenotypic differentiation of strains OD1^T and YOx^T from O. flavum TA17^T and from each other. Therefore, it is concluded that the strains OD1^T and YOx^T represent novel species within the genus Oxalicibacterium , for which the names Oxalicibacterium horti sp. nov. (type strain OD1^T=DSM 21640^T=NBRC 13594^T) and Oxalicibacterium faecigallinarum sp. nov. (type strain YOx^T=DSM 21641^T=CCM 2767^T) are proposed.