自制多脏器保存液对大鼠睾丸一氧化氮合酶的影响***

背景：在睾丸移植过程中,低温保存和缺血可导致睾丸产生氧自由基而损伤睾丸组织。 目的：观察自制多脏器保存液对低温保存大鼠睾丸一氧化氮合酶的影响。 方法：采用自制多脏器保存液和UW液低温保存大鼠睾丸,分别于保存24,48,72 h时切取睾丸,测定睾丸组织内的总抗氧化能力和一氧化氮合酶活性。 结果与结论：自制多器官保存液低温保存各时点大鼠睾丸一氧化氮合酶活性和总抗氧化能力与UW液组比较差异均无显著性意义(P > 0.05)。表明自制多脏器保存液能明显减轻低温保存大鼠睾丸氧自由基损伤,其作用与经典的美国威斯康星大学UW保存液基本相当。     

The preservation of nerve cells in rat neostriatal slices maintained in vitro: A morphological study

The in vitro preservation of neurons in 300 micron thin neostriatal slices, which are routinely used for electrophysiological studies, was examined by light and electron microscopy and was compared to 700 micron thick neostriatal slices. The thin slices displayed well-preserved cells after up to 5 h of incubation. This finding correlated well with whether electrical activity could be recorded. In cross-section, the thin slices consisted of three layers: the inner layer contained many intact cells (80%) and was sandwiched between the outer layers where deteriorating cells predominated. In contrast to the thin slices, the thick slices (700 micron) displayed no layering of intact cells in cross-section. Instead, the majority of cells throughout these thick slices was swollen (98%), with only small patches of intact cells. Two types of deteriorating cells were apparent: swollen cells and dark (pycnotic) cells. The proportion of swollen cells increased with incubation time. In the thin slices this swelling occurred in the outer layers with the middle layer of intact cells remaining relatively unchanged over long incubation periods, whereas all cells in the thick slices were swollen after 2 h of incubation. Dark cells were localized to the outer portion of both slices and the number of such dark cells did not change with incubation time.     

The Modified Checklist for Autism in Toddlers: An Initial Study Investigating the Early Detection of Autism and Pervasive Developmental Disorders

Autism, a severe disorder of development, is difficult to detect in very young children. However, children who receive early intervention have improved long-term prognoses. The Modified Checklist for Autism in Toddlers (M-CHAT), consisting of 23 yes/no items, was used to screen 1,293 children. Of the 58 children given a diagnostic/developmental evaluation, 39 were diagnosed with a disorder on the autism spectrum. Six items pertaining to social relatedness and communication were found to have the best discriminability between children diagnosed with and without autism/PDD. Cutoff scores were created for the best items and the total checklist. Results indicate that the M-CHAT is a promising instrument for the early detection of autism.     

Usefulness of high-concentration calcium chloride solution for correction of activated partial thromboplastin time (APTT) in patients with high-hematocrit value

INTRODUCTION: Pseudoprolongation of activated partial thromboplastin time (APTT) is a serious problem in anticoagulation therapy for patients with high hematocrit, such as cyanotic congenital heart diseases. APTT pseudoprolongation occurs when APTT assay is performed using routinely used vacuum sampling tubes containing citrate. Because the plasma fraction is small in high-hematocrit blood, the prescribed volume of citrate would be excessive for APTT assay, resulting in prolongation of clotting or APTT pseudoprolongation. CLSI--The Clinical and Laboratory Standards Institute (formerly NCCLS) method is the established method to correct the pseudoprolongation. However, the CLSI method needs repeated blood drawings and time-consuming, complicate procedures. Thus, alternative simple method is desired. METHOD: We examined whether APTT pseudoprolongation would be prevented by the increase in free calcium ion concentration by using high-concentration calcium chloride solution for the assay. Blood samples were obtained from 15 patients with high hematocrit (65+/-6%) who had cyanotic congenital heart disease. RESULT: Conventional APTT assay using 0.025 mol/L calcium chloride solution gave greater APTT compared with the CLSI method (51.7+/-11.8 vs. 34.6+/-4.7 s, p<0.001). However, when 0.035 mol/L calcium chloride solution was used, APTT (36.6+/-5.8 s) was similar to that obtained from the CLSI method. There was a good correlation in APTT values between high-calcium chloride solution method and the CLSI method (the slope=0.57, r2=0.49). CONCLUSION: High-calcium chloride solution method is useful to correct APTT pseudoprolongation. Because of the simplicity and the need of a single blood drawing, this method would reduce the burdens of not only patients but also clinical laboratory.     

Survival of neural precursor cells in growth factor-poor environment: implications for transplantation in chronic disease

A key issue for therapeutic neural stem cell transplantation in chronic diseases is the long-term survival of transplanted cells in the brain. The normal adult central nervous system does not support the survival of transplanted cells. Presumably, the limited availability of trophic factors maintains the survival of resident cells but is insufficient for supporting the survival of transplanted cells. Specifically, in multiple sclerosis, a chronic relapsing disease, it would be necessary to maintain long-term survival of transplanted cells through phases of relapses and remissions. It may be beneficial to transplant cells as early as possible, in a form that will keep their survival independent of tissue support and ready for immediate mobilization upon tissue demand during disease relapse. In the present study, we examined whether, in the form of neurospheres, multipotential neural precursor cells (NPCs) survive in a growth factor-poor environment while maintaining their potential to respond to environmental cues. We found that after removal of growth factors from the culture medium of neurospheres in vitro, NPC proliferation decreased significantly, but most cells survived for a prolonged time and maintained their stem cell characteristics. After re-exposure to growth factors, neurosphere cells resumed proliferation and could differentiate along neural lineages. Furthermore, neurospheres, but not single NPCs, that were transplanted into the brain ventricles of intact animals survived within the ventricles for at least a month and responded to induction of experimental autoimmune encephalomyelitis and brain inflammation by extensive migration into the brain white matter and differentiated into glial lineage cells.     

The antiplatelet effect of daily low dose enteric-coated aspirin in man: A time course of onset and recovery

We have studied the onset and recovery of inhibition of platelet function by low dose aspirin. Enteric-coated aspirin 50mg daily was administered to five human volunteers for five weeks and then 100mg daily was given for a further five weeks. We studied platelet aggregation and thromboxane formation in response to a range of stimuli: ADP, adrenaline, arachidonate and collagen, and also measured thromboxane formation after coagulation of whole blood (serum thromboxane). The onset of inhibition of platelet aggregation was progressive over several days for each of the four platelet stimuli, and was synchronous with the inhibition of thromboxane formation. Maximum inhibition occurred by day three for the weak stimuli ADP and adrenaline, by day five for the stronger stimuli arachidonate and collagen, but did not occur until day eight for serum thromboxane. Further inhibitory effects on both aggregation and thromboxane generation were observed after 100mg daily. Two weeks after the cessation of aspirin the responses to collagen and arachidonate and serum thromboxane had returned to normal. Platelet aggregation in response to the weaker stimuli, ADP and adrenaline, still showed detectable inhibition two weeks after cessation of aspirin, but had returned to normal by four weeks. These experiments provided no evidence for an effect of aspirin on platelets separate to its effect on cyclooxygenase. The onset and recovery of inhibition of platelet function by low dose aspirin was dependent on the strength of the stimulus studied.     

The Modified Checklist for Autism in Toddlers: A Follow-up Study Investigating the Early Detection of Autism Spectrum Disorders

Autism spectrum disorders (ASD) often go undetected in toddlers. The Modified Checklist for Autism in Toddlers (M-CHAT) was used to screen 3,793 children aged 16–30 months from low- and high-risk sources; screen positive cases were diagnostically evaluated. Re-screening was performed on 1,416 children aged 42–54 months. Time1 Positive Predictive Value (PPV) was .36 for the initial screening and .74 for the screening plus follow-up telephone interview; values were similar for Time2 PPV. When separating referral sources, PPV was low for the low-risk sample but acceptable with the follow-up telephone interview. Children with ASD from the low-risk and high-risk samples were highly similar. Results indicate that the M-CHAT continues to be a promising instrument for the early detection of ASD.     

The firing patterns of spinal neurons: in situ patch‐clamp recordings reveal a key role for potassium currents

Neuron firing patterns underpin the detection and processing of stimuli, influence synaptic interactions, and contribute to the function of networks. To understand how intrinsic membrane properties determine firing patterns, we investigated the biophysical basis of single and repetitive firing in spinal neurons of hatchling Xenopus laevis tadpoles, a well‐understood vertebrate model; experiments were conducted in situ. Primary sensory Rohon–Beard (RB) neurons fire singly in response to depolarising current, and dorsolateral (DL) interneurons fire repetitively. RB neurons exhibited a large tetrodotoxin‐sensitive sodium current; in DL neurons, the sodium current density was significantly lower. High‐voltage‐activated calcium currents were similar in both neuron types. There was no evidence of persistent sodium currents, low‐voltage‐activated calcium currents, or hyperpolarisation‐activated currents. In RB neurons, the potassium current was dominated by a tetraethylammonium‐sensitive slow component (I_Ks); a fast component (I_Kf), sensitive to 4‐aminopyridine, predominated in DL neurons. Sequential current‐clamp and voltage‐clamp recordings in individual neurons suggest that high densities of I_Ks prevent repetitive firing; where I_Ks is small, I_Kf density determines the frequency of repetitive firing. Intermediate densities of I_Ks and I_Kf allow neurons to fire a few additional spikes on strong depolarisation; this property typifies a novel subset of RB neurons, and may activate escape responses. We discuss how this ensemble of currents and firing patterns underpins the operation of the Xenopus locomotor network, and suggest how simple mechanisms might underlie the similar firing patterns seen in the neurons of diverse species.     

The maintenance effect of cognitive-behavioural treatment groups for the Chinese parents of children with intellectual disabilities in Melbourne, Australia: a 6-month follow-up study

Background Caring for a child with intellectual disability can be stressful. No data on the longer‐term effects of cognitive–behavioural treatment (CBT) on parents from a Chinese‐speaking background who have children with intellectual disabilities are available in the literature. This study attempted to fill this research gap by examining the maintenance effect of CBT among the Chinese parents of such children in Melbourne, Australia. Method Thirty‐nine participants took part in our CBT groups and attended follow‐up meetings. A questionnaire comprising four instruments, the Parenting Stress Index (PS) – Parent Domain, General Health Questionnaire‐12 (GHQ‐12), Abbreviated Quality of Life Enjoyment and Satisfaction Questionnaire (Q‐LES‐Q‐18) and Dysfunctional Attitude Scale (DAS), was administered to the participants at the pre‐ and post‐test stage and at the 6‐month follow‐up. Results One‐way repeated‐measures analyses of variance revealed significant time and group effects in the PS (F_2,27 = 16.93, P < 0.001), Q‐LES‐Q‐18 (F_2,27 = 15.98, P < 0.001), GHQ‐12 (F_2,27 = 81.93, P < 0.001) and DAS (F_2,27 = 15.50, P < 0.001) scores at the three measurement times. The participants continued to maintain significant improvements in mental health and quality of life and declines in the severity of parenting stress and dysfunctional attitudes at the 6‐month follow‐up. Effect size analyses revealed mostly large differences in the foregoing measurements (Cohen's d = 0.76–2.18) between the pre‐test and 6‐month follow‐up. Employing a cut‐off score of 3/4 in the GHQ‐12 to identify at‐risk and not‐at‐risk cases, approximately 90.5% of the participants could be classified as not‐at‐risk at the follow‐up. Lastly, regression analyses showed that changes in DAS scores significantly predicted changes in the GHQ‐12 and Q‐LES‐Q‐18 scores at the follow‐up. Conclusions This study provides preliminary evidence of the 6‐month maintenance effect of CBT groups for the Melbourne‐resident Chinese parents of children with intellectual disabilities.