Cataracts in cichlid fish

Bilateral cataracts were detected in a group of aquarium-raised tilapia (Sarotherodon mossambicus). Vision impairment was manifested as random swimming into objects, but the fish appeared to function normally otherwise. Most of the lens was opaque, with the outer extent of the cortex and subcapsular region remaining transparent. Skeletal abnormalities, ie, deformed fins, abnormal jaws, and curvature of the spine, were observed in affected individuals. Histologically, there was progressive degeneration of the cataractous portion as the affected fish matured. Preliminary breeding experiments indicated that the condition may be inherited.     

Androgen regulation of hypothalamic neurons containing gonadotropin-releasing hormone in a cichlid fish: integration with social cues

Reproduction in vertebrates is regulated by internal signals such as hormone levels and by external signals such as social interactions. In an African cichlid fish, Haplochromis burtoni, the effect of social interactions is evident in the hypothalamo-pituitary-gonadal (HPG) axis of males. Territorial males, characterized by aggressive and reproductive activity, have significantly larger hypothalamic gonadotropin-releasing hormone (GnRH)-containing neurons and larger testes than nonterritorial males. Furthermore, a switch in the social status of an adult male causes a corresponding change in GnRH neuron size and testis size. Here we show that the GnRH-containing neurons in the hypothalamus of adult territorial males are also influenced by gonadal hormones. Castration of territorial males caused GnRH neurons to increase in size. This neuronal hypertrophy in castrated animals was prevented either by testosterone (T) or 11-ketotestosterone (KT) treatment. Estradiol (E2) treatment did not reduce GnRH cell size in castrated animals. These results suggest that androgens reduce the size of GnRH cells through negative feedback. Since E2 had no effect, androgen influence on GnRH cell size appears to be independent of aromatization. These data are consistent with the hypothesis that the setpoint for hypothalamic GnRH cell size is determined by social cues and that this setpoint is maintained by negative feedback from gonadal androgens.     

Capillaria (Hepatocapillaria) cichlasomae (Nematoda: Capillariidae) from the liver of the cichlid fish Cichlasoma urophthalmus from Yucatan, Mexico

Although various hematological disorders have been considered to be etiologic factors in deep vein thrombosis (DVT), the involvement of dysplasminogenemia (DPG) in DVT has not been studied in detail. In 72 consecutive DVT patients, the presence of DVT was suspected based on a history of lower limb swelling and tenderness with acute onset, and was confirmed by duplex scanning, radioisotope venography, or contrast venography. DPG was identified by the observation of dissociation between the activity and antigenicity of plasminogen. Of the 72 patients, 9 (12.5%) were diagnosed as having DPG, and several antithrombin-III deficiency and protein C and S deficiency were identified. The mean age of the genetically normal and DPG patients was 52 +/- 15 and 40 +/- 15 years, respectively (p < 0.05). Thus, these findings suggest that DPG is deeply related to the development of DVT, and that abnormality of the fibrinolytic system is one of the major etiologic factors in DVT.     

Prevalence of workplace smoking bans in Victoria

Restrictions on smoking in the Victorian workplace have been measured since 1988. This paper investigates whether the trend of increasing prevalence of total bans found between 1988 and 1992 has continued. Estimates are based on workers' reports of the restrictions on smoking that apply at their workplaces. For indoor workers a total ban on smoking restrictions in the workplace has increased from 58% in 1992 to 66% in 1995. White collar workers continue to enjoy a higher rate of protection than blue collar workers. Factories, warehouses, hotels and restaurants are the worksites least likely to have restrictions. Bans result in considerable exiled smoking: half the smokers reported going out to smoke during working hours on their last work day.     

Spectral tuning and molecular evolution of rod visual pigments in the species flock of cottoid fish in Lake Baikal

Lake Baikal in Eastern Siberia is the deepest and one of the largest and most ancient lakes in the world. However, even in the deepest regions, oxygenation levels do not fall below 75-80% of the surface levels. This has enabled a remarkable flock of largely endemic teleost fish of the sub-order Cottoidei to colonize all depth habitats. We have previously shown that species that occupy progressively deeper habitats show a blue shift in the peak wavelength of absorbance (lambda max) of both their rod and cone visual pigments; for the rod pigments, a number of stepwise shifts occur from about 516 nm in littoral species to about 484 nm in abyssal species. By sequencing the rod opsin gene from 11 species of Baikal cottoids that include representatives from all depth habitats, we have been able to identify four amino acid substitutions that would account for these shifts. The effect of each substitution on lambda max is approximately additive and each corresponds to a particular lineage of evolution.     

Field Measurement of Ship Waves in Victoria Harbor

Field measurement of ship waves has been carried out in Victoria Harbor of Hong Kong. The wave data were collected at 18 monitoring stations by the underwater pressure/current instrument S4ADW and a floating wave rider TYPE 1156. It is found that the wave conditions in the study area are predominantly affected by the ship-generated waves under normal weather conditions. By comparing with the wind-generated waves in the open region which are irregular but with dominant directional characteristics, the existing harbor–wave field is much more complex. The irregular ship–wave field is not statistically stationary. It is also found that the ship–wave spectra are either of multiple peaks or have wide crests without distinct peaks.     

Persistence of maladaptive responses in schizophrenia.

30 schizophrenic patients and 30 psychiatric aides were required in 4 experimental tasks to change their responses to meet changing conditions. It was hypothesized that (a) schizophrenic patients are more likely than normals to continue a response after it becomes ineffective; (b) the persistence of the maladaptive response is a function of the severity of schizophrenia. As predicted, the patients persisted longer than the aides in the first learned but later maladaptive responses, and there was some evidence that degree of resistance to change was related to the severity of schizophrenia in the patient. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Persistence of the fetal circulation

A 43-year-old woman with bilateral Adie's tonic pupils had a segment of one iris sphincter that contracted spontaneously every few seconds, but was not influenced by light, near vision, or eye movements.     

从反叛到超越——论波特小说中米兰达的精神指归

当代美国南方女作家凯瑟琳·安·波特的<老人>和<灰色马,灰色的骑手>刻画了一个反叛者形象--米兰达,关注的是人怎样在逃避不了的荒诞的世界里找到生存的立足点,回归自然本真的精神家园.面对南方家族历史,米兰达能正视失败,执着于真实;面对战争、瘟疫、死亡和战时美国社会现实中的种种伪善和非人道行为,米兰达在反叛中存在,努力前行.为了确立自我,实现身与心的和谐平衡,更为了捍卫人格尊严,米兰达表现出西西弗斯式的反抗精神:虽然处在一种被抛的境地,孤立无援,但她毅然地重新开始,在失望中实现超越.     

Persistence of multiple serovars of Neisseria gonorrhoeae

The nm23 gene that encodes nucleoside diphosphate (NDP) kinase has been proposed as a candidate tumor metastasis suppressor in rodent experimental carcinoma models and several types of human carcinomas. The present studies were designed to investigate, by immunohistochemical analysis, whether thyroid tissues express the nm23-H1/NDP kinase and, if so, whether the nm23-H1/NDP kinase expression is correlated to tumor metastasis suppressor potential in thyroid tumors. We found that normal thyroid epithelial cells were stained weakly but homogeneously by mouse monoclonal anti-nm23-H1/NDP kinase antibody. The staining intensity of the nm23-H1/NDP kinase in benign thyroid tumors tended to be weaker than that in normal thyroid tissues. In contrast, a series of malignant thyroid tumors expressed differently the nm23-H1/NDP kinase: the intensity of the nm23-H1/NDP kinase staining was stronger in 22 of 49 malignant tumors (45%), similar in 24 (49%), and weaker in 3 (6%) compared to that in normal tissues. The comparison of the staining intensity of the nm23-H1/NDP kinase in primary lesions of tumors with lymph node metastases and those without metastases revealed no statistically significant difference. In addition, there was also no significant difference in the nm23-H1/NDP kinase staining intensity of primary and metastatic lymph node lesions of tumors with lymph node metastases. These data indicate that the nm23-H1/NDP kinase may not be a good predictive marker for tumor regional metastatic potential in malignant thyroid tumors. We conclude that in thyroid tumors the nm23-H1/NDP kinase expression may be dissociated from metastasis suppressor activity.     

Persistence of dyslexics' phonological awareness deficits.

Examined the phonological awareness skills of dyslexic children, adults with childhood diagnoses of dyslexia, and good readers at various age levels. Comparisons of the dyslexics to good readers of the same age or the same reading level indicated that dyslexics do not acquire appropriate levels of phoneme awareness, regardless of their age or reading levels, although they eventually acquire appropriate levels of onset-rhyme awareness. Even adults with fairly high levels of word recognition skill show phoneme awareness deficits. For normal readers, reliable increases in phoneme awareness were associated with age and reading level, whereas for dyslexic Ss these associations were not reliable. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Persistence of runway performance after septal lesions in rats.

Assigned 32 male Wistar albino rats to groups receiving bilateral septal lesions or control operations. Septal lesions prevented the partial reinforcement extinction effect after 48 acquisition trials. Septal Ss showed increased resistance to extinction following continuous reinforcement but decreased resistance to extinction following partial reinforcement. Analysis of the acquisition data indicated that the lesions retarded the development of approach-avoidance conflicts associated with reward and nonreward. In a 2nd study, 16 septal and 16 control Ss received 96 acquisition trials. Extended training allowed the development of conflict responses under partial reinforcement, and the Ss with lesions were indistinguishable from controls during extinction. Following continuous reinforcement, septal lesions produced slower extinction of response. It is concluded that the lesions interfered with the development of feedback from frustration, approach-avoidance conflicts, and frustration tolerance. (21 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)