Oxygen doping of cobalt-single-atom coordination enhances peroxymonosulfate activation and high-valent cobalt-oxo species formation.

The high-valent cobalt-oxo species (Co(IV)=O) is being increasingly investigated for water purification because of its high redox potential, long half-life, and antiinterference properties. However, generation of Co(IV)=O is inefficient and unsustainable. Here, a cobalt-single-atom catalyst with N/O dual coordination was synthesized by O-doping engineering. The O-doped catalyst (Co-OCN) greatly activated peroxymonosulfate (PMS) and achieved a pollutant degradation kinetic constant of 73.12 min-1 g-2, which was 4.9 times higher than that of Co-CN (catalyst without O-doping) and higher than those of most reported single-atom catalytic PMS systems. Co-OCN/PMS realized Co(IV)=O dominant oxidation of pollutants by increasing the steady-state concentration of Co(IV)=O (1.03 × 10-10 M) by 5.9 times compared with Co-CN/PMS. A competitive kinetics calculation showed that the oxidation contribution of Co(IV)=O to micropollutant degradation was 97.5% during the Co-OCN/PMS process. Density functional theory calculations showed that O-doping influenced the charge density (increased the Bader charge transfer from 0.68 to 0.85 e), optimized the electron distribution of the Co center (increased the d-band center from -1.14 to -1.06 eV), enhanced the PMS adsorption energy from -2.46 to -3.03 eV, and lowered the energy barrier for generation of the key reaction intermediate (*O*H2O) during Co(IV)=O formation from 1.12 to 0.98 eV. The Co-OCN catalyst was fabricated on carbon felt for a flow-through device, which achieved continuous and efficient removal of micropollutants (degradation efficiency of >85% after 36 h operation). This study provides a new protocol for PMS activation and pollutant elimination through single-atom catalyst heteroatom-doping and high-valent metal-oxo formation during water purification.

Chlorination of isothiazolinone biocides: kinetics, reactive species, pathway, and toxicity evolution.

Due to the Covid-19 pandemic, the worldwide biocides application has been increased, which will eventually result in enhanced residuals in treated wastewater. At the same time, chlorine disinfection of secondary effluents and hospital wastewaters has been intensified. With respect to predicted elevated exposure in wastewater, the chlorination kinetics, transformation pathways and toxicity evolution were investigated in this study for two typical isothiazolinone biocides, methyl-isothiazolinone (MIT) and chloro-methyl-isothiazolinone (CMIT). Second-order rate constants of 0.13 M-1·s-1, 1.95 × 105 M-1·s-1 and 5.14 × 105 M-1·s-1 were determined for the reaction of MIT with HOCl, Cl2O and Cl2, respectively, while reactivity of CMIT was around 1-2 orders of magnitude lower. While chlorination of isothiazolinone biocides at pH 7.1 was dominated by Cl2O-oxidation, acidic pH and elevated Cl- concentration favored free active chlorine (FAC) speciation into Cl2 and increased overall isothiazolinone removal. Regardless of the dominant FAC species, the elimination of MIT and CMIT resulted in an immediate loss of acute toxicity under all experimental conditions, which was attributed to a preferential attack at the S-atom resulting in subsequent formation of sulfoxides and sulfones and eventually an S-elimination. However, chlorination of isothiazolinone biocides in secondary effluent only achieved <10% elimination at typical disinfection chlorine exposure 200 mg·L-1·min, but was predicted to be remarkably increased by acidizing solution to pH 5.5. Alternative measures might be needed to minimize the discharge of these toxic chemicals into the aquatic environment.

Synergistic effects of ozone/peroxymonosulfate for isothiazolinone biocides degradation: Kinetics, synergistic performance and influencing factors.

Synergistic effects of ozone (O3) and peroxymonosulfate (PMS, HSO5-) for isothiazolinone biocides degradation was studied. The synergistic ozonation process (O3/PMS) increased the efficiency of methyl-isothiazolinone (MIT) and chloro-methyl-isothiazolinone (CMIT) degradation to 91.0% and 81.8%, respectively, within 90 s at pH 7.0. This is 30.6% and 62.5% higher than the corresponding ozonation efficiency, respectively. Total radical formation value (Rct,R) for the O3/PMS process was 24.6 times that of ozonation alone. Calculated second-order rate constants for the reactions between isothiazolinone biocides and (kSO4-,MIT and kSO4-,CMIT) were 8.15 × 109 and 4.49 × 109 M-1 s-1, respectively. Relative contributions of O3, hydroxyl radical (OH) and oxidation to MIT and CMIT removal were estimated, which were 15%, 45%, and 40% for O3, OH and oxidation to MIT, and 1%, 67%, and 32% for O3, OH and oxidation to CMIT at pH 7.0, respectively. Factors influencing the O3/PMS process, namely the solution pH, chloride ions (Cl-), and bicarbonate (HCO3-), were evaluated. Increasing the solution pH markedly accelerated O3 decay and OH and formation, thus weakening the relative contribution of O3 oxidation while enhancing that of OH and . Cl- had a negligible effect on MIT and CMIT degradation. Under the dual effect of bicarbonate (HCO3-) as inhibitor and promoter, low concentrations (1-2 mM) of bicarbonate weakly promoted MIT and CMIT degradation, while high concentrations (10-20 mM) induced strong inhibition. Lastly, oxidation performance of O3 and O3/PMS processes for MIT and CMIT degradation in different water matrices was compared.

Promotive effects of vacuum-UV/UV (185/254 nm) light on elimination of recalcitrant trace organic contaminants by UV-AOPs during wastewater treatment and reclamation: A review.

The use of vacuum-UV/UV (185/254 nm) for trace organic contaminants (TOrCs) elimination during wastewater treatments has attracted much attention. Advanced oxidation processes which combine VUV/UV and additional oxidants (vacuum-UV/UV-based advanced oxidation processes, VUV/UV-AOPs) provide a promising method for eliminating recalcitrant and toxic TOrCs for wastewater reclamation. Researches in this area are increasing but the promoting effects, mechanisms, and influencing factors have not been well summarized. A comprehensive discussion of the limitations of this technique and future research directions is needed. VUV/UV-AOPs have considerable synergistic effects by increasing usage of VUV/UV photons and the oxidant, which increases radical generation. In terms of elimination kinetics, VUV/UV-AOPs outperform conventional UV-AOPs and VUV/UV processes in most cases; a 1.2-87.7-fold increase of the fluence-based kinetic constant is achieved. In terms of energy efficiency per order (EE/O) of TOrCs elimination, the EE/O of VUV/UV-AOPs only accounts for 4% of UV-AOPs and 63% of VUV/UV. However, VUV/UV-AOPs still need to be further investigated. Firstly, although VUV and UV processes have similar radical formation pathways, limited information is available on the quantum yields of photolysis and radical formation of oxidants under VUV irradiation. Secondly, optimization of VUV/UV-AOPs operating conditions, especially oxidant dosage and water-flow patterns, is needed. Thirdly, VUV/UV-AOPs are significantly inhibited by organic and inorganic matters, but the mechanisms of inhibition on VUV/UV scattering, radical quenching, and radical conversion are not well understood. Such inhibition suggests that the use of VUV/UV-AOPs would be limited to relatively clear water treatment, e.g., reverse osmosis effluent for potable water reuse and ultrapure water production. Related research is needed to establish a clearer scheme for VUV/UV-AOPs in terms of the spatial distribution of radical species in the VUV/UV irradiation system and the relevant optimization method for promoting oxidation performance.

Outcomes of a novel bubble ultra-wide field viewing system for vitreoretinal surgery.

PURPOSE: To report the clinical outcomes and evaluate the efficacy of a novel bubble ultra-wide field viewing system for vitreoretinal surgery. DESIGN: Prospective, noncomparative, interventional case series. PARTICIPANTS: One hundred and fifty-one eyes of 146 consecutive patients with proliferative diabetic retinopathy (PDR), vitreous haemorrhage originating from retinal vein occlusion (VH-RVO), epiretinal membrane (EM), macular hole (MH) or retinal detachment (RD) who underwent vitreoretinal surgery using the bubble ultra-wide field viewing system were included. METHODS: A standard phacoemulsification was performed on each patient. Core humour and mid-peripheral vitreous humour were removed using a planoconcave lens. A suitably sized bubble was infused to attach to the posterior capsule or the anterior chamber depending on the integrity of the posterior capsule. The planoconcave lens and the air bubble formed the wide-angle viewing system, through which peripheral vitrectomy was performed. MAIN OUTCOME MEASURES: Range of applications, field of view, model validation and complications were recorded. RESULTS: The new ultra-wide field viewing system was successfully applied in all eyes, including 34 with PDR, 28 VH-RVO, 28 EM, 25 MH and 36 RD. Peripheral vitrectomy, local or panretinal laser photocoagulation, and removal of the peripheral proliferative membrane were successfully performed while viewing through this system. Maximum peripheral retinal area observable during the procedure was positively correlated with pupil diameter. Model analysis results showed that when the pupil diameter was 6 mm, the maximum field of view was approximately 128.1- 148.0 degrees with this system. Of 142 eyes, the main intraoperative complication was iatrogenic retinal breaks (IRBs) in 8 eyes (5.3%) and posterior capsule injury by vitreous cutter during bubble removal in 6 eyes (4.2%). The postsurgery mean best-corrected visual acuity (BCVA) (0.48 ± 0.39 logMAR) was significantly improved compared with the preoperative mean BCVA (1.60 ± 1.08 logMAR, p < 0.001). No incidents of postoperative choroidal detachment, secondary glaucoma or endophthalmitis were recorded. CONCLUSIONS: For patients with lens excision or absence, vitreoretinal surgery can be successfully performed using the novel viewing system described here. The system is a safe, convenient and economical ultra-wide field viewing system with a wide range of applications.

Understanding the influence of pre-ozonation on the formation of disinfection byproducts and cytotoxicity during post-chlorination of natural organic matter: UV absorbance and electron-donating-moiety of molecular weight fractions.

Pre-ozonation can reduce the formation of disinfection byproducts (DBPs) and related adverse effects during subsequent chlorination, but the change of each molecular weight (MW) fraction during each step of combined pre-ozonation and post-chlorination has not been well illustrated. In this study, it was investigated in terms of electron-donating-moieties (EDMs) and UVA254 for a representative natural organic matter from Suwanee river (SRNOM). Pre-ozonation suppressed the post-chlorination of SRNOM through oxidation of almost all EDMs (>85%) and UVA254 (>90%) in high MW fractions (HMW, >3.2 kDa) and moderate EDMs (43%) and UVA254 (72%) in medium MW fractions (MMW, 1.0-3.2 kDa). Furthermore, pre-ozonation led to comparable abatements of EDMs and UVA254 for HMW fractions, but lower abatement of EDMs than UVA254 for MMW fractions. However, when t-BuOH was used as an •OH-quencher, pre-ozonation led to a few instances in which there were higher abatements of EDMs than UVA254 for the MMW fraction. These findings suggested that the HMW fraction dominantly underwent ring-cleavage of phenols via O3- or •OH-oxidation. Differently, the MMW fraction underwent ring-cleavage of phenols and quinones-formation via O3-oxidation, but occasionally underwent hydroxylation and hydro-phenol formation via •OH-oxidation. Because of forehand elimination of reactive moieties (e.g. EDMs), pre-ozonation obviously inhibited the formation of representative DBPs (67%-84% inhibition), total organic chloride (51% inhibition) and cytotoxicity (31% inhibition), but may have promoted the formation of carbonyl-DBPs (trichloroacetone and chloral hydrate). When compared with UVA254, EDMs would better for surrogate of DBPs formation. EDM abatement surrogated the formation of total organic chlorine (TOCl) and cytotoxicity following a two-stage phase, possibly because the speciation of DBPs and transformation products varied with the abatement of EDMs.

The promotions on radical formation and micropollutant degradation by the synergies between ozone and chemical reagents (synergistic ozonation): A review.

The combination of ozone (O3) and chemical reagents (such as H2O2) shows synergies on the radical formation and micropollutant degradation. The promoting performance was associated with various parameters including chemical reagents, micropollutants, solution pH, and the water matrix. In this review, we summarized existing knowledge on radical formation pathways, radical yields, and radical oxidation for different synergistic ozonation processes in various water matrices (such as groundwater, surface water, and wastewater). The increase of radical yields by synergistic ozonation processes was positively related to the increase of O3-decay, with the increase being 1.1-4.4 folds than ozonation alone (0.2). Thus, synergistic ozonation can promote the degradation rate and efficiency of O3-resistant micropollutants (second order rate constant, kP,O3 < 200 M-1 s-1), but only slightly affects or even minorly inhibits the degradation of O3-reactive micropollutants (kP,O3 > 200 M-1 s-1). The water matrices, such as the dissolved organic matters, negatively suppressed the degradation of micropollutant by quenching O3-oxidation and radical oxidation (i.e. maximum promoting was decreased by 1.3 times), but may positively extend the promoting effects of synergistic ozonation to micropollutants that are more reactive to O3 (i.e. kP,O3 was extended from <200 to <2000 M-1 s-1). The formation of bromate would be increased through increasing radical oxidation by synergistic ozonation, but can be depressed by relative higher H2O2 as the reducing agent of HOBr/OBr- intermediate. The increase in bromate formation by O3/permononsulfate is a considerable concern due to permononsulfate cannot reduce the HOBr/OBr- intermediate.

Identification of a Pharmacological Biomarker for the Bioassay-Based Quality Control of a Thirteen-Component TCM Formula (Lianhua Qingwen) Used in Treating Influenza A Virus (H1N1) Infection.

As chemical analysis for quality control (QC) of traditional Chinese medicine (TCM) formula is difficult to guarantee the effectiveness, a bioassay method that combines QC with evaluation of therapeutic effects has been developed to assess the TCM quality. Here, we chose a thirteen-component TCM formula, Lianhua Qingwen capsule (LHQW), as a representative sample, to explore the pivotal biomarkers for a bioassay and to investigate close association between QC and pharmacological actions. Initially, our results showed that chemical fingerprinting could not effectively distinguish batches of LHQW. Pharmacological experiments indicated that LHQW could treat influenza A virus (H1N1) infection in the H1N1 mouse model, as claimed in clinical trials, by improving pathologic alterations and bodyweight loss, and decreasing virus replication, lung lesions and inflammation. Furthermore, by using serum metabolomics analysis, we identified two important metabolites, prostaglandin F2α and arachidonic acid, and their metabolic pathway, arachidonic acid metabolism, as vital indicators of LHQW in treatment of influenza. Subsequently, macrophages transcriptomics highlighted the prominent role of cyclooxygenase-2 (COX-2) as the major rate-limiting enzyme in the arachidonic acid metabolism pathway. Finally, COX-2 was validated by in vivo gene expression and in vitro enzymatic activity with 43 batches of LHQW as a viable pharmacological biomarker for the establishment of bioassay-based QC. Our study provides systematic methodology in the pharmacological biomarker exploration for establishing the bioassay-based QC of LHQW or other TCM formulas relating to their pharmacological activities and mechanism.

Is there section deformation resulting in differential change of nuclear numerical densities along the z axis of thick methacrylate or paraffin sections?

The optical disector, a three-dimensional counting frame or probe in stereology, is often positioned in the middle (depth) of a thick section for unbiased nuclear counting. Using 30-40 µm thick methacrylate or paraffin sections for nuclear counting of neurons with the optical disector, however, some studies showed markedly higher nuclear densities at 10% of the section thickness near the top or bottom surface of the section, suggestive of deformation of section along its z axis and thus affecting the number estimation. To verify the findings, this study obtained two sets of 12-14 methacrylate sections (average thicknesses 21.7 and 29.4 µm) and two sets of 12 paraffin sections (average thicknesses 13.8 and 29.2 µm) from mature rat testes. Each section was used to count round spermatid nuclei in the seminiferous epithelium densely packed with the cells, using 3-4 consecutive disectors placed vertically (along the z axis of the section) from the top surface of the section, through the whole section thickness (two sets of methacrylate and paraffin sections) or in 80-83% of the thickness (other sections). The results demonstrated that, overall, there were no considerable nonuniform changes of the nuclear densities along the z axis of the sections.

Quantitative (stereological) study of the epididymis and seminal vesicle in the rat from young to old.

There is a scarcity of morphometric data on the developmental and ageing changes in the epididymis and seminal vesicle in young and old rats. Eighty-six normal male Sprague-Dawley rats were randomly sampled from a cohort of animals aged 1-36 months (7-9 animals each age group). The epididymis and seminal vesicle (with the closely attached coagulating gland) were removed, and methacrylate resin-embedded sections were prepared for quantitative study of key histological structures by light microscopy. Stereological methods (point counting and optical disector) were used to estimate the total volumes of sperm mass, secretion (glandular lumen) and other structures and the number of spermatozoa. The results showed that the rapid growth of the reproductive organs was between 1 and 4 months of age. The epididymis stored the largest volume of sperm mass or number of spermatozoa at 12 months of age, but thereafter until 36 months of age, the sperm storage did not markedly diminish. The volume of secretion stored in the seminal vesicular gland declined by more than 35% from a plateau at 12-18 months until 36 months of age while that in the coagulating gland declined by more than 30% from a plateau at 18-24 months until 36 months of age.

Stereological study on the number of synapses in the rat spinal dorsal horn with painful diabetic neuropathy induced by streptozotocin.

Our previous studies showed that direct injury to the sciatic nerve (chronic constriction injury or axotomy) is associated with a numerical increase in synaptic number in the rat spinal dorsal horn. The aim of this study was to determine whether painful diabetic neuropathy (PDN) was also associated with numerical changes in the synaptic or neuronal numbers in the spinal dorsal horn. Overall, 17 adult SD rats were allocated randomly into the control group (n=5) and the streptozotocin (STZ) group (n=12). STZ was injected intraperitoneally to induce diabetes. In the STZ group, seven rats (STZ-H) showed hyperglycemia (fasting blood glucose >11.1 mM) and the rest of the five rats (STZ-N) did not. Rats were fed and observed for 28 days after hyperglycemia. Two of the seven STZ-H rats died of infection during the observation period. Body weight and paw withdraw threshold (PWT) decreased in the rest of the five STZ-H rats. Twenty-eight days after hyperglycemia, the L5 segment of the spinal cord was removed; paraffin-embedded sections were prepared and stained with Nissl's method and synaptophysin immunohistochemistry, respectively. The optical dissector (a stereological technique) was used to estimate the numbers of neurons and synapses in the spinal dorsal horn. Compared with the control group, the synaptic number and ratio between the numbers of synapses and neurons in the L5 segment of the spinal dorsal horn were increased significantly in the STZ-H rats (P<0.05), whereas the neuronal number did not change significantly (P>0.05). Parameters of STZ-N rats showed no significant changes. In conclusion, PDN, a form of neuropathic pain, is also associated with a synaptic plasticity (numerical increase) in the spinal dorsal horn. This numerical change might be the reason for central sensitization resulting in reduced pain threshold, enhanced responsiveness, and expanded receptive fields associated with PDN. Therefore, our studies indicate that neuropathic pain conditions with different etiologies might show the same synaptic numerical plasticity changes.

Efficacy and safety of Chinese herbal medicine Wenxin Keli for ventricular premature be ats: A systematic review.

BACKGROUND: To evaluate the efficacy and safety of the Chinese herbal extract Wenxin Keli, alone or in combination with Western medicine, for ventricular premature beats. METHODS: This systematic review was registered at PROSPERO (registration number CRD42013003200). A systematic literature search of 8 core electronic databases and 3 clinical trial registries in Chinese and English, yielded 10 trials whose randomness verified by contacting the authors. The included trials were assessed by the Cochrane risk of bias tool. RESULTS: Wenxin Keli might be more efficacious than placebo (Change of VPBs numbers, RR, 1.61, 95%CI, 1.48-1.76, P<0.00001, I2=0%;VPBs- related symptom, RR, 2.10, 95%CI, 1.91-2.30, P<0.00001, I2=0%), and the dual therapy of Wenxin Keli plus amiodarone might also be more effective than the monotherapy of amiodarone (Change of VPBs numbers, RR, 1.23, 95%CI, 1.10-1.39, P=0.0005, I2=0%; VPBs- related symptom, RR, 1.51., 95%CI, 1.30-1.76, P<0.00001, I2=0%), whereas Wenxin Keli might be comparable to metoprolol, propafenone or mexiletine (Change of VPBs numbers: metoprolol, RR, 1.01, 95%CI, 0.91-1.11, P=0.88, I2=0%; propafenone, RR, 1.05, 95%CI, 0.93-1.19, P=0.44, I2=0%; mexiletine, RR, 1.06, 95%CI, 0.96-1.17, P=0.28. VPBs- related symptom: metoprolol, RR, 0.95, 95%CI, 0.87-1.04, P=0.27, I2=0%, propafenone. RR, 1.10, 95%CI, 0.93-1.30, P=0.29, I2=29%, mexiletine,RR, 0.94, 95%CI, 0.78-1.12, P=0.47). Participants with ventricular premature beats' numbers<360 beats/h or with coronary heart disease benefited the most of the Wenxin Keli therapy (Change of VPBs numbers:RR, 1.10, 95%CI, 1.02-1.20, P=0.02, I2=44%; RR, 1.71, 95%CI, 1.18-2.49, P=0.005, I2=54%, respectively). The safety analysis revealed that Wenxin Keli did not statistically significant differed from the Western medicine in respect of the incidence of total adverse drug reactions (RR, 0.59, 95%CI, 0.35-1.01, P=0.05, I2=0%), but Wenxin Keli might be associated with a reduced risk of proarrhythmic reactions (P=0.007). The quality of the methodology of included trials was generally low. Several limitations existed that affected the validity of the findings, including the small sample size, insufficient randomization methods, poorly defined eligibility criteria, short duration of follow-up, absence of hard endpoints, and high risk of publication bias(P=0.013). CONCLUSIONS: Wenxin Keli might be a promising alternative and complementary medicine for ventricular premature beats.

Morphometric study of the testis and reproductive tract (including sperm granuloma) after vasectomy in mature rats.

By utilizing the rabbit model, previous studies have found good evidence indicating that vasectomy-induced spermatogenic damage is pressure-mediated: the damage occurs when the occluded reproductive tract is unable to accommodate additional spermatozoa produced by the testis. More studies with the more commonly used rat model have shown, however, controversial results on whether and why the damage occurs. In this study, 12 mature male Sprague-Dawley rats were subjected to unilateral vasectomy: double ligation (without severing) of the vas deferens exposed via a small inguinal incision; 37 days after the operation, the testes, epididymides, vasa deferentia (juxta-epididymal segments), and sperm granulomas (at the vasectomy site) were removed to obtain methacrylate resin-embedded sections and morphometric studies carried out with light microscopy. Marked spermatogenic damage with spermatids and spermatocytes depleted in the seminiferous epithelium in 43% of the seminiferous tubule profiles was demonstrated in 5 of the 12 testes on the vasectomized side, and the damage was associated with smaller or absent sperm granulomas; in the other 7 testes with essentially normal spermatogenesis, there was an increase (by 111% on average) in the volume of the tubule lumen, associated with larger granulomas or granulomas containing more spermatozoa. There was an overall increase (by 66%) in the thickness of the rete testis in the 12 testes; the epididymis or vas deferens showed no distension. It seems therefore that the spermatogenic damage induced by vasectomy in rats is pressure-mediated as well, and that variation in the damage depends mainly on the postoperative development of the sperm granuloma.

[Impact of ethane dimethane sulfonate on the histological structures of seminal vesicles in adult rats].

OBJECTIVE: To study the effect of ethane dimethane sulfonate (EDS) injection on the volumes of different histological structures in the seminal vesicles of adult rats. METHODS: Twenty-seven male SD rats aged approximately 90 days were randomly divided into a control group (n = 14) and an EDS group (n = 13) to receive one intraperitoneal injection of normal saline and EDS (75 mg/kg bodyweight), respectively. At 7 and 12 days after treatment, the unilateral seminal vesicles were removed, methacrylate resin-embedded sections prepared and the total volumes of various structures in the seminal vesicles estimated using stereological methods. RESULTS: EDS treatment almost completely destroyed the Leydig cells in the testis, resulting in a drastic testosterone deficiency. The volume of the seminal vesicle (including the coagulating gland attached to the vesicle) was decreased by 53% in the 7 d EDS group (n = 6) in comparison with the 7 d control group (n = 7) ([138.2 +/- 12.9] vs [64.9 +/- 3.6] mm3, P < 0.01), but showed no significant difference between the 7 d and the 12 d EDS (n = 7) groups ([64.9 +/- 3.6] vs [55.4 +/- 7.7] mm3, P > 0.05). The total volumes of the glandular lumen, glandular epithelium, smooth muscular layer and adventitia were decreased by 96.7, 80.3, 57.6 and 67.0%, respectively, in the 12 d EDS group as compared with the 12 d control group (n = 7). CONCLUSION: EDS induces drastic testosterone deficiency in adult rats, and significantly reduces the total volumes of the seminal vesicle lumen, glandular epithelium, smooth muscular layer and adventitia.

[Histological effects of unilateral spermatic cord torsion without removal of the ipsilateral necrotic testis on the contralateral testis in rats].

OBJECTIVE: To investigate the protective effect of retarded removal of the unilateral necrotic testis after long-time (> 24 h) spermatic cord torsion on the contralateral testis in rats. METHODS: Thirty-three male SD rats aged 21 -42 days were divided into a sham-operation group (n = 11), a torsion-reservation group (n = 12) and a torsion-orchiectomy group (n = 10). The rats of the sham-operation group received dartos pouch orchidopexy on the left testis, while those of the latter two groups underwent 720 degrees unilateral spermatic cord torsion on the left side. Ninety-six hours later, the rats of the torsion-reservation group received detorsion with the ipsilateral testis preserved, while those of the torsion-orchiectomy group underwent orchiectomy. Three months after operation, blood samples were obtained from the rats for measurement of serum testosterone and antisperm antibodies by ELISA, and meanwhile testes and epididymides were harvested for determination of the volumes of various structures and the diameter of seminiferous tubules with stereological methods. RESULTS: There were no significant differences in the level of serum testosterone among the three groups. Anti-sperm antibody positive was found in only 1 animal in the torsion-reservation group. The Leydig cell nuclei in the contralateral testis appeared larger in the torsion groups than in the sham-operation group. Marked morphological changes were observed in 1, 3 and 0 of the animals in the sham-operation, torsion-reservation and torsion-orchiectomy group, respectively, mainly including atrophy of seminiferous tubules and reduced number of spermatogenic cells. The volume of the contralateral testis was increased by 19% and 21% in the torsion-reservation and torsion-orchiectomy group, respectively, in comparison with that in the sham-operation group (P < 0.05). No significant differences were observed in the volume of seminiferous tubules of the contralateral testis among the sham-operation, torsion-reservation and torsion-orchiectomy groups ([1.15 +/- 0.07], [1.30 +/- 0.04] and [1.35 +/- 0.05] cm3). The volume of the interstitial tissue was significantly increased in the latter two groups ([0.36 +/- 0.02 and 0.34 +/- 0.03] cm3) as compared with the former ([0.25 +/- 0.02] cm3) (P < 0.05). The diameters of the seminiferous tubules exhibited no significant differences among the three groups ([226.00 +/- 7.00], [223.00 +/- 6.00] and [221.00 +/- 3.0] microm). CONCLUSION: Long-time unilateral spermatic cord torsion may result in compensatory hypertrophy of the contralateral testis, and orchiectomy does not significantly affect the histology of the contralateral testis and epididymis.

Long-term effect of vasectomy on spermatogenesis in men: a morphometric study.

Spermatogenic damage may occur after vasectomy, and the damage is pressure mediated, occurring when the occluded reproductive tract is unable to accommodate additional sperm produced by the testis. This study aimed to determine the long-term effect of vasectomy on spermatogenesis in humans and clarify how the balance between sperm production in the testis and sperm storage in or removal from the tract might be maintained. During inguinal hernia repair, an open biopsy was performed to obtain testicular tissue blocks from 51 Chinese men (aged ≥50 years), of whom 25 (control group) had not undergone vasectomy and 26 (vasectomized group) had undergone bilateral vasectomy 22-42 years before. Methacrylate resin-embedded testicular sections were made, and morphometric studies were performed using light microscopy. In addition, sizes of the testis and epididymis were estimated with ultrasonography. The testicular tissue blocks obtained from one control and seven vasectomized men consisted almost completely of connective tissue. In the other 43 men, significant differences were not found between the two groups in the testicular or epididymal size, qualitative histology or quantitative parameters including the mean diameter or volume fraction of the seminiferous tubules. In conclusion, sperm production and sperm storage/removal reached a static equilibrium after vasectomy, likely due to spermatogenic degeneration or less sperm production as a result of aging or due to vasectomy-induced testicular (interstitial) fibrosis. Thus, complications that might occur in association with overproduction of sperm and distension of the tract would disappear or be relieved with time.

Magnetic resonance imaging for pancreatic ductal adenocarcinomas induced by N-nitrosobis (2-oxopropyl) amine in Syrian golden hamsters.

OBJECTIVES: This study aimed to study magnetic resonance imaging (MRI) findings of pancreatic ductal adenocarcinomas (PDAs) induced by N-nitrosobis (2-oxopropyl) amine (BOP) in Syrian hamsters. METHODS: A total of 101 female hamsters, 8 weeks old, were randomized into 3 groups. They were randomized into a BOP-treated group (n = 80; with weekly subcutaneous injections of BOP [10 mg/kg body weight] for 7 consecutive weeks), a saline-treated group (n = 16), and an untreated group (n = 5). Hamsters underwent abdominal MRI on 1.5-T MR scanners with a dedicated animal radiofrequency coil. Findings of the tumor from the MRI were compared those from histology. RESULTS: Pancreata in the saline-treated and in the untreated groups were normal. In the BOP-treated group, there were 23 and 31 BOP-induced PDAs on macroscopy and microscopy, respectively. Of the PDAs detected on macroscopy, 65.2% were depicted on MRI. As early as 13 and 19 weeks after the first injection of BOP, PDAs in hamsters were found on histology and MRI, respectively. Moreover, the tumor volume on MRI was correlated with the tumor weights excised (r = 0.96, P = 0.000, n = 15). CONCLUSIONS: N-nitrosobis (2-oxopropyl) amine successfully induced PDAs in hamsters. Magnetic resonance imaging has the ability to detect healthy pancreas and PDAs in hamsters and has the potential to monitor the development of PDAs.

Enriched environment increases the total number of CNPase positive cells in the corpus callosum of middle-aged rats.

It had been reported that enriched environment was beneficial for the brain cognition, neurons and synapses in cortex and hippocampus. With diffusion tensor imaging (DTI), several studies recently found the trained-induced larger corpus callosum. However, the effect of enriched environment on the oligodendrocytes in corpus callosum has not been explored with the unbiased stereological methods. In current study, the effect of enriched environment on the total number of 2',3'-cyclic nucleotide 3'-phosphodiesterase (CNPase) positive cells in middle-aged rat corpus callosum was investigated by means of immunohistochemical techniques and the unbiased stereological methods. We found that, when compared to standard rats, the spatial learning capacity of enriched-environment rats was significantly increased. The total number of the CNPase positive cells in the corpus callosum of enriched-environment middle-aged rats was significantly increased when compared to standard rats. The present study provided, to the best of our knowledge, the first evidence of environmental enrichment-induced increases in the total number of CNPase positive cells in the corpus callosum of middle-aged rats.

[Testosterone-induced spermatogenic impairment is associated with looser arrangement of spermatogenic cells in rats].

OBJECTIVE: To determine whether testosterone-induced intra-testicular testosterone withdrawal and therefore spermatogenic impairment is associated with looser arrangement of spermatogenic cells in rats. METHODS: Adult male SD rats received intramuscular injection of testosterone undecanoate at 19 mg/(kg x 15 d) for 130 days, and then testicular tissue blocks were obtained for the preparation of methacrylate resin-embedded sections and observation of the changes in testicular histology. RESULTS: Apart from such changes as impaired spermiogenesis and spermiation, apparently looser arrangement of spermatogenic cells was seen in 11.5% of the seminiferous tubule profiles, with radial cracks (empty spaces) running towards the tubule lumen being formed between lines, bundles or groups of spermatogenic cells (mainly spermatids and spermatocytes). CONCLUSION: Looser arrangement of spermatogenic cells is one of the key histological changes resulting from intra-testicular testosterone withdrawal in rats.

Number of synapses increased in the rat spinal dorsal horn after sciatic nerve transection: a stereological study.

We recently found that the number of synapses in the spinal dorsal horn, as estimated by stereological techniques, increased by 86% after chronic constriction injury of sciatic nerve in rats. In this study, we aimed to reveal whether transection of sciatic nerve was also associated with a plasticity change in the number of synapses. 18 adult SD rats were randomly divided into 3 groups undergoing (i) unilateral sham operation, (ii) unilateral sciatic nerve transection, and (iii) unilateral sciatic nerve transection with postoperative medication (parecoxib) for 3 days, respectively. 28 days postoperation, the L4-6 segment of the spinal cord was removed; paraffin-embedded sections were prepared and stained with Nissl's method and synaptophysin immunohistochemistry. The optical disector (a contemporary stereological technique) was used to estimate the numbers of neurons and synapses in the spinal dorsal horn. Compared to the non-operated side, the axotomy induced a 74.3% increase in the number of synapses per unit length of spinal cord or a 67.4% increase in the ratio between the numbers of synapses and neurons in the middle tissue block from the L4-6 segment on the operated side but not in either the rostral or caudal tissue block. Parecoxib had no effect on the parameters. In conclusion, peripheral nerve injury, model for neuropathic pain, is associated with a synaptic plasticity (numerical increase) in the spinal dorsal horn.