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1.
Heredity (Edinb) ; 106(4): 592-602, 2011 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-20606690

RESUMO

Pigmentation is one of the most variable traits within and between Drosophila species. Much of this diversity appears to be adaptive, with environmental factors often invoked as selective forces. Here, we describe the geographic structure of pigmentation in Drosophila americana and evaluate the hypothesis that it is a locally adapted trait. Body pigmentation was quantified using digital images and spectrometry in up to 10 flies from each of 93 isofemale lines collected from 17 locations across the United States and found to correlate most strongly with longitude. Sequence variation at putatively neutral loci showed no evidence of population structure and was inconsistent with an isolation-by-distance model, suggesting that the pigmentation cline exists despite extensive gene flow throughout the species range, and is most likely the product of natural selection. In all other Drosophila species examined to date, dark pigmentation is associated with arid habitats; however, in D. americana, the darkest flies were collected from the most humid regions. To investigate this relationship further, we examined desiccation resistance attributable to an allele that darkens pigmentation in D. americana. We found no significant effect of pigmentation on desiccation resistance in this experiment, suggesting that pigmentation and desiccation resistance are not unequivocally linked in all Drosophila species.


Assuntos
Drosophila/fisiologia , Adaptação Fisiológica , Animais , Drosophila/genética , Feminino , Fluxo Gênico , Variação Genética , Masculino , Pigmentação , Seleção Genética
3.
Hum Exp Toxicol ; 38(8): 899-913, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-30995857

RESUMO

Cryptorchidism (CPT), the most common male congenital abnormality, is variably associated with other male reproductive tract problems. We evaluated if cryptorchid rats develop enhanced testicular susceptibility to dibutyl phthalate (DBP) or acrylamide (AA) after extended exposure. Three studies with rats were performed: (1) in utero and postnatal exposure to DBP or AA; (2) establishment of CPT and orchiopexy; and (3) in utero and postnatal exposures to DBP or AA associated with CPT/orchiopexy. Seminiferous tubules were histologically scored according to the severity of lesions: (1) Rats exposed to DBP (score 1.5) or AA (score 1.1) presented mostly preserved spermatogenesis. Some seminiferous tubules showed vacuolated germinative epithelium, germ cell apoptosis, and a Sertoli cell-only (SCO) pattern. (2) CPT (score 3.3) resulted in decreased absolute testes weights, degenerated and SCO tubules, and spermatogenesis arrest that were reversed by orchiopexy (score 1.1). (3) Exposure to DBP or AA with CPT/orchiopexy led to atrophic testes, spermatogenesis arrest, germ cell exfoliation/multinucleation, and SCO tubules (both chemicals score 2.5). Exposure to chemicals such as DBP or AA prevented the recovery of cryptorchid testes by orchiopexy. The possible role of environmental contaminants should be considered when looking for factors that modulate human testicular disorders associated with CPT.


Assuntos
Acrilamida/toxicidade , Criptorquidismo/cirurgia , Dibutilftalato/toxicidade , Testículo/efeitos dos fármacos , Animais , Criptorquidismo/patologia , Modelos Animais de Doenças , Feminino , Masculino , Troca Materno-Fetal , Orquidopexia , Gravidez , Ratos Sprague-Dawley , Testículo/patologia
4.
J Natl Cancer Inst ; 90(1): 19-25, 1998 Jan 07.
Artigo em Inglês | MEDLINE | ID: mdl-9428778

RESUMO

BACKGROUND: It was observed in the early 1970s that saccharin produced bladder cancer in rats. However, it has been unclear whether sodium saccharin when consumed by humans poses a substantial carcinogenic hazard. Numerous epidemiologic studies have not shown any evidence of increased urothelial proliferation associated with ingestion of sodium saccharin. PURPOSE: Our purpose was to determine the effects of long-term feeding of sodium saccharin to three species of nonhuman primates. METHODS: Twenty monkeys of three species (six African green, seven rhesus, six cynomolgus, and one hybrid [of rhesus male and cynomolgus female parentage]) were treated with sodium saccharin (25 mg in the diet/kg body weight daily for 5 days a week) beginning within 24 hours after birth and continuing for up to 24 years. Sixteen monkeys (seven rhesus and nine cynomolgus) served as controls. During their last 2 years of life, urine was collected from selected treated and control animals and evaluated for various urinary chemistries and for the presence of calculi, microcrystalluria, and precipitate. Urinary bladders were examined by light microscopy and by scanning electron microscopy. RESULTS: Sodium saccharin treatment had no effect on the urine or urothelium in any of these monkeys. There was no evidence of increased urothelial cell proliferation, and there was no evidence of formation of solid material in the urine. CONCLUSION: Although the dose of sodium saccharin administered to these monkeys was only five to 10 times the allowable daily intake for humans, the results provide additional evidence that sodium saccharin is without a carcinogenic effect on the primate urinary tract.


Assuntos
Carcinógenos/toxicidade , Sacarina/toxicidade , Bexiga Urinária/efeitos dos fármacos , Urina/química , Urotélio/efeitos dos fármacos , Animais , Carcinógenos/administração & dosagem , Divisão Celular/efeitos dos fármacos , Feminino , Haplorrinos , Masculino , Microscopia Eletrônica de Varredura , Sacarina/administração & dosagem , Ultrassonografia , Bexiga Urinária/diagnóstico por imagem
5.
Cancer Res ; 58(12): 2557-61, 1998 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-9635578

RESUMO

Sodium ascorbate, like other sodium salts such as saccharin, glutamate, and bicarbonate, produces urinary alterations when fed at high doses to rats, which results in mild superficial urothelial cytotoxicity and regeneration but not tumors in a standard 2-year bioassay. Sodium saccharin was shown to produce a low incidence of bladder tumors in rats if administered in a two-generation bioassay. In the present study, we evaluated sodium ascorbate in a two-generation bioassay that involved feeding to the male and female parental F344 rats for 4 weeks before mating, feeding the dams during gestation and lactation, and then feeding the weaned (at 28 days of age) male F1 generation rats for the remainder of their lifetime (up to 128 weeks of the experiment). Dietary levels of 1.0, 5.0, and 7.0% sodium ascorbate were tested. At 5.0 and 7.0% sodium ascorbate, there was an increase in urinary bladder urothelial papillary and nodular hyperplasia and the induction of a few papillomas and carcinomas. There was a dose-responsive increase in renal pelvic calcification and hyperplasia and inhibition of the aging nephropathy of rats even at the level of 1% sodium ascorbate. Because the short-term urothelial effects of sodium ascorbate in rats are inhibited by treatments producing urinary acidification to pH < 6.0, we coadministered high doses of long-term NH4Cl to groups of rats with 5.0 or 7.0% sodium ascorbate to evaluate the long-term effects. The combination of 7.0% sodium ascorbate plus 2.78% NH4Cl in the diet was toxic, and the group was terminated early during the course of the experiment. The group fed 5.0% sodium ascorbate plus 2.04% NH4Cl showed complete inhibition of the urothelial effects of sodium ascorbate and significant inhibition of its renal effects. We also demonstrated the presence of a calcium phosphate-containing urinary precipitate in rats fed sodium ascorbate at all doses, in a dose-responsive manner. The formation of the precipitate was inhibited by coadministration with NH4Cl. The proliferative effects of sodium ascorbate on the male rat urinary tract in this study are similar to those seen with sodium saccharin when administered in a two-generation bioassay. Mechanistic information suggests that this is a high-dose, rat-specific phenomenon.


Assuntos
Ácido Ascórbico/efeitos adversos , Neoplasias da Bexiga Urinária/induzido quimicamente , Cloreto de Amônio/farmacologia , Animais , Testes de Carcinogenicidade , Interações Medicamentosas , Feminino , Hiperplasia/induzido quimicamente , Masculino , Papiloma/induzido quimicamente , Papiloma/patologia , Ratos , Ratos Endogâmicos F344 , Neoplasias Uretrais/induzido quimicamente , Neoplasias Uretrais/patologia , Neoplasias da Bexiga Urinária/patologia , Sistema Urinário/efeitos dos fármacos
6.
Integr Physiol Behav Sci ; 40(1): 17-27, 2005.
Artigo em Inglês | MEDLINE | ID: mdl-16491928

RESUMO

We have shown previously that phenytoin impairs learning in rats in several different behavioral paradigms (Churchill et al., 1998, 2003; Banks et al., 1999). The present study has examined this drug's effects on performance in a delayed match-to-place water maze paradigm developed by Steele and Morris (1999). We find that phenytoin retards performance, but only when the inter-trial interval (ITI) is short (i.e., 15-sec). With longer ITIs (i.e., 20-min, 2-hr), the performance of the phenytoin-treated rats was quite comparable to the controls. We suggest that this pattern of results stems from a disruption of spatial working memory, perhaps due to the effects of the drug on hippocampal function (cf., Churchill et al., 1998, 2003). This disruption is, however, not so profound that consolidation is prevented.


Assuntos
Anticonvulsivantes/farmacologia , Aprendizagem por Discriminação/efeitos dos fármacos , Memória de Curto Prazo/efeitos dos fármacos , Orientação/efeitos dos fármacos , Fenitoína/farmacologia , Retenção Psicológica/efeitos dos fármacos , Animais , Aprendizagem da Esquiva/efeitos dos fármacos , Condicionamento Operante/efeitos dos fármacos , Reação de Fuga/efeitos dos fármacos , Lobo Frontal/efeitos dos fármacos , Hipocampo/efeitos dos fármacos , Masculino , Ratos , Ratos Sprague-Dawley , Tempo de Reação/efeitos dos fármacos
7.
Obstet Gynecol ; 86(3): 461-5, 1995 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-7651662

RESUMO

OBJECTIVE: To survey the nonsurgical diagnostic techniques for distinguishing adenomyosis, and to determine whether one technique offers diagnostic advantages. DATA SOURCES: We conducted a thorough search of the MEDLINE data base and identified English-language papers on adenomyosis published during the last 28 years. Reference lists of retrieved articles were also examined for additional source documents. METHODS OF STUDY SELECTION: We reviewed 238 articles. Papers on nonsurgical diagnostic techniques published in peer-reviewed journals were selected for inclusion. DATA EXTRACTION AND SYNTHESIS: We determined nonsurgical diagnostic techniques for distinguishing adenomyosis to be hysterosalpingography, abdominal ultrasound, transvaginal sonography, and magnetic resonance imaging (MRI). Studies were divided into these four categories, reviewed, and summarized accordingly. Recent reports suggest that noninvasive modalities, eg, transvaginal sonography and MRI, have, made possible the nonsurgical diagnosis of adenomyosis. CONCLUSION: Because of its widespread availability and patient tolerance, transvaginal sonography remains the primary screening modality for imaging the female pelvis. However, for cases in which sonography cannot detect adenomyosis, MRI provides a viable alternative and should be the definitive diagnostic modality of choice.


Assuntos
Endometriose/diagnóstico , Abdome/diagnóstico por imagem , Feminino , Humanos , Histerossalpingografia , Imageamento por Ressonância Magnética , Programas de Rastreamento/métodos , Cuidados Pré-Operatórios , Sensibilidade e Especificidade , Ultrassonografia , Vagina/diagnóstico por imagem
8.
Toxicol Sci ; 59(1): 68-74, 2001 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-11134545

RESUMO

Inorganic arsenic is a known human carcinogen of the skin and respiratory tract. Epidemiologic evidence indicates that it is also carcinogenic to the urinary bladder and other internal organs. Lack of an animal model has limited progress on understanding the mechanism of arsenic carcinogenesis. It was recently reported that high doses of an organic arsenical, dimethylarsinic acid (DMA), increased urinary bladder tumors in rats when administered in the diet or in the drinking water for 2 years, with the female being more sensitive than the male. We previously showed that high doses of DMA (40 or 100 ppm of the diet) fed for 10 weeks increased urothelial cell proliferation in the rat. Treatment with DMA also increased renal calcification and increased urinary calcium concentration. In 2 experiments, we examined the urothelial proliferative effects of treatment with 100 ppm DMA in the diet in female F344 rats for 2 and 10 weeks and for 6 and 24 h, and 3, 7, and 14 days. Cytotoxic changes in the urothelium were evident by SEM as early as 6 h after treatment was begun. Foci of cellular necrosis were detected after 3 days of treatment, followed by widespread necrosis of the urothelium after 7 days of treatment. The bromodeoxyuridine (BrdU) labeling index was not increased until after 7 days of treatment, suggesting that administration of DMA results in cytotoxicity with necrosis, followed by regenerative hyperplasia of the bladder epithelium. Although the rat provides an animal model to study the urothelial effects of DMA, the relevance of this finding to inorganic arsenic carcinogenesis in humans must be extrapolated cautiously, due to the high doses of DMA necessary to produce these changes in the rat and the differences in metabolism of arsenicals in rodents, especially rats, compared to humans.


Assuntos
Ácido Cacodílico/toxicidade , Carcinógenos/toxicidade , Regeneração/efeitos dos fármacos , Urotélio/efeitos dos fármacos , Animais , Peso Corporal/efeitos dos fármacos , Bromodesoxiuridina/metabolismo , Ácido Cacodílico/administração & dosagem , Calcinose/induzido quimicamente , Calcinose/patologia , Cálcio/urina , Carcinógenos/administração & dosagem , Divisão Celular/efeitos dos fármacos , Creatinina/urina , Esquema de Medicação , Ingestão de Alimentos/efeitos dos fármacos , Feminino , Rim/efeitos dos fármacos , Rim/patologia , Nefropatias/induzido quimicamente , Nefropatias/patologia , Microscopia Eletrônica de Varredura , Tamanho do Órgão/efeitos dos fármacos , Ratos , Ratos Endogâmicos F344 , Bexiga Urinária/efeitos dos fármacos , Bexiga Urinária/patologia , Urotélio/fisiologia , Urotélio/ultraestrutura
9.
Toxicol Sci ; 59(2): 346-51, 2001 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-11158728

RESUMO

Ortho-phenylphenol (OPP) and sodium ortho-phenylphenate (NaOPP) are pesticides used commercially in the food industry that have been shown to be carcinogenic to rat urothelium. Dietary administration of 1.25% OPP or 2.0% NaOPP caused increased incidences of urothelial hyperplasia and eventually caused tumors in male F344 rats, with NaOPP apparently having a more potent effect. In other studies, various sodium salts such as saccharin and ascorbate enhanced bladder carcinogenesis, although the acid forms of these salts did not. In studies with high dietary doses of these sodium salts, an amorphous precipitate was produced in the urine; precipitate formation was pH dependent. In previous experiments in which high doses of OPP were fed for up to 17 weeks, severe hyperplasia of the urothelium was produced, but without the formation of an urinary amorphous precipitate, calculi, or abnormal microcrystalluria. In addition, we found no evidence of OPP-DNA adduct formation in the urothelium. The present study was conducted to determine if feeding NaOPP * 4 H(2)0 to male F344 rats as 2.0% of the diet resulted in the formation of an amorphous precipitate in the urine, and if NaOPP caused an increased mineral concentration in the urine and/or kidneys. NaOPP administration produced a higher urinary pH than did OPP fed as 1.25% of the diet. Neither amorphous precipitate nor other solids were observed in the urine of the OPP or NaOPP-treated rats, and urinary calcium concentrations in the treated groups were similar to control. OPP and NaOPP had similar proliferative effects on rat urothelium after 10 weeks of treatment by light microscopy, scanning electron microscopy (SEM), and bromodeoxyuridine (BrdU) labeling indices. The results of this study indicate that formation of abnormal urinary solids is not part of the mechanism by which OPP or NaOPP exert their effects on the rat bladder epithelium.


Assuntos
Compostos de Bifenilo/toxicidade , Fungicidas Industriais/toxicidade , Urotélio/efeitos dos fármacos , Animais , Compostos de Bifenilo/administração & dosagem , Peso Corporal/efeitos dos fármacos , Dieta , Ingestão de Líquidos/efeitos dos fármacos , Ingestão de Alimentos/efeitos dos fármacos , Fungicidas Industriais/administração & dosagem , Concentração de Íons de Hidrogênio , Masculino , Microscopia Eletrônica de Varredura , Ratos , Ratos Endogâmicos F344 , Urinálise , Bexiga Urinária/efeitos dos fármacos , Bexiga Urinária/patologia , Urotélio/ultraestrutura
10.
Brain Res ; 910(1-2): 142-52, 2001 Aug 10.
Artigo em Inglês | MEDLINE | ID: mdl-11489264

RESUMO

Injury-induced reorganization of central somatotopic maps is a phenomenon that has proven to be useful for elucidating the mechanisms and time course of neural plasticity. To date, the overwhelming majority of this line of research has focused on such plastic events in cortical areas, at the expense of subcortical structures. In this study, we used multi-unit electrophysiological recording techniques to assess the somatotopic organization of brainstem and thalamic areas following chronic survival from paired median and ulnar nerve section in adult squirrel monkeys. We report that the extent of cutaneously-driven reorganization in both the cuneate nucleus of the brainstem and the ventroposterior lateral nucleus of the thalamus is comparable to that previously documented for area 3b of cortex. These observations are consistent with those previously reported in thalamus, and are unique for brainstem.


Assuntos
Vias Aferentes/fisiopatologia , Bulbo/fisiopatologia , Plasticidade Neuronal/fisiologia , Traumatismos dos Nervos Periféricos , Doenças do Sistema Nervoso Periférico/fisiopatologia , Tato/fisiologia , Núcleos Ventrais do Tálamo/fisiopatologia , Potenciais de Ação/fisiologia , Adaptação Psicológica/fisiologia , Vias Aferentes/patologia , Animais , Padronização Corporal/fisiologia , Mapeamento Encefálico , Bulbo/patologia , Regeneração Nervosa/fisiologia , Neurônios/fisiologia , Nervos Periféricos/patologia , Nervos Periféricos/fisiopatologia , Doenças do Sistema Nervoso Periférico/patologia , Estimulação Física , Recuperação de Função Fisiológica/fisiologia , Saimiri/anatomia & histologia , Saimiri/fisiologia , Núcleos Ventrais do Tálamo/patologia
11.
Brain Res ; 954(1): 68-72, 2002 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-12393234

RESUMO

Following peripheral nerve transection, reorganizational plasticity has been reported to occur in two phases, one immediate and one more protracted. GABA (gamma-aminobutyric acid) has been implicated in the immediate "unmasking" phase of reorganization. We have used quantitative autoradiography to assess potential changes in GABA(A) and GABA(B) receptor binding in primate somatosensory cortex following peripheral nerve injury. Here we report reductions in GABA(A) receptor binding in layer IV of primate somatosensory cortex deprived of its normal activating inputs for 2-5 h by peripheral nerve transection.


Assuntos
Plasticidade Neuronal/fisiologia , Traumatismos dos Nervos Periféricos , Receptores de GABA-A/metabolismo , Córtex Somatossensorial/metabolismo , Animais , Autorradiografia , Axotomia , Nervo Mediano/lesões , Receptores de GABA-B/metabolismo , Saimiri , Fatores de Tempo , Nervo Ulnar/lesões
12.
Fertil Steril ; 61(6): 1165-7, 1994 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-8194637

RESUMO

The persuasive data not only illustrate a familial tendency towards adenomyosis but also emphasize that adenomyosis can be diagnosed noninvasively and accurately by MRI. A possible familial predisposition toward or a direct familial cause of adenomyosis warrants further investigation.


Assuntos
Endometriose/genética , Adulto , Endometriose/diagnóstico , Endometriose/etiologia , Endométrio/patologia , Saúde da Família , Feminino , Humanos , Imageamento por Ressonância Magnética , Pessoa de Meia-Idade
13.
Food Chem Toxicol ; 40(6): 793-9, 2002 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-11983274

RESUMO

Numerous chemicals administered to rodents at relatively high doses produce urinary tract calculi, resulting in erosions or ulcerations of the urothelium, consequent regenerative hyperplasia, and ultimately tumors. This is a high-dose (threshold) phenomenon, which appears to occur more readily in rodents than in primates, including humans. Several anatomic and urinary physiologic differences between rodents and humans affect the quantitative extrapolation from results in rodent bioassays to human risk assessment. For most chemicals producing tumors by this mode of action, human exposures are significantly lower than would be expected to be required for production of calculi, and therefore pose no carcinogenic hazard to humans.


Assuntos
Cálculos Urinários/complicações , Neoplasias Urológicas/etiologia , Animais , Humanos , Camundongos , Ratos , Medição de Risco , Cálculos Urinários/patologia , Neoplasias Urológicas/epidemiologia , Neoplasias Urológicas/patologia
14.
J Abnorm Child Psychol ; 30(4): 349-59, 2002 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-12109488

RESUMO

Examined hypothesized gender and comorbidity differences in the observed classroom behavior of children with attention deficit hyperactivity disorder (ADHD). The behavior of 403 boys and 99 girls with ADHD, ages 7-10, was compared (a) to observed, sex-specific classroom behavior norms, (b) by sex, and (c) by comorbid subgroups. Boys and girls with ADHD deviated significantly from classroom norms on 15/16 and 13/16 categories, respectively. Compared to comparison girls, girls with ADHD had relatively high rates of verbal aggression to children. Boys with ADHD engaged in more rule-breaking and externalizing behaviors than did girls with ADHD, but the sexes did not differ on more "neutral," unobtrusive behaviors. The sex differences are consistent with notions of why girls with ADHD are identified and referred later than boys. Contrary to hypothesis, the presence of comorbid anxiety disorder (ANX) was not associated with behavioral suppression; yet, as hypothesized, children with a comorbid disruptive behavior disorder (DBD) had higher rates of rule-breaking, and impulsive and aggressive behavior, than did children with ADHD alone and those with ADHD+ANX. Elevated rates of ADHD behaviors were also observed in children with comorbid DBD, indicating that these behaviors are truly present and suggesting that reports of higher ADHD ratings in this subgroup are not simply a consequence of negative halo effects and rater biases.


Assuntos
Transtorno do Deficit de Atenção com Hiperatividade/diagnóstico , Transtornos do Comportamento Infantil/diagnóstico , Determinação da Personalidade , Transtornos de Ansiedade/diagnóstico , Transtornos de Ansiedade/epidemiologia , Transtornos de Ansiedade/psicologia , Transtorno do Deficit de Atenção com Hiperatividade/epidemiologia , Transtorno do Deficit de Atenção com Hiperatividade/psicologia , Transtornos de Deficit da Atenção e do Comportamento Disruptivo/diagnóstico , Transtornos de Deficit da Atenção e do Comportamento Disruptivo/psicologia , Criança , Transtornos do Comportamento Infantil/epidemiologia , Transtornos do Comportamento Infantil/psicologia , Comorbidade , Feminino , Humanos , Controle Interno-Externo , Masculino , Prognóstico , Fatores Sexuais , Comportamento Social
15.
Integr Physiol Behav Sci ; 39(3): 192-206, 2004.
Artigo em Inglês | MEDLINE | ID: mdl-15929501

RESUMO

The present study examined the effects of ovariectomy and subsequent estradiol replacement on learning in young adult rats using a set of instrumental avoidance paradigms differing in the nature and extent of prior experience in the learning context. Thus, one group of animals was placed directly into avoidance learning (AV). A second group was trained on an appetitive task first, and then transferred into the aversive context (AP-AV). The third group was exposed to the training context without any specific appetitive response requirement, and then required to learn an active avoidance response (Context-AV). We found that estradiol (OVX+E) impaired avoidance acquisition in all cases relative ovariectomized controls (OVX). In contrast, while avoidance learning is improved following appetitive training or context exposure in both OVX+E and OVX animals, the OVX+E animals profit to a greater extent from the appetitive or context experience than do the OVX controls. We suggest that this difference may be due to enhanced attentional processes or improved hippocampal processing of contextual factors. Thus, estradiol negatively influences simple associative avoidance learning in ovariectomized rats, but appears to promote positive transfer.


Assuntos
Aprendizagem por Associação/fisiologia , Aprendizagem da Esquiva/fisiologia , Estradiol/fisiologia , Transferência de Experiência/fisiologia , Animais , Comportamento Apetitivo/fisiologia , Condicionamento Clássico/fisiologia , Feminino , Ovariectomia , Ratos , Ratos Sprague-Dawley
16.
Integr Physiol Behav Sci ; 38(4): 253-71, 2003.
Artigo em Inglês | MEDLINE | ID: mdl-15119377

RESUMO

Rats with selective lesions of the nucleus basalis magnocellularis (NBM) and sham-lesion control animals were tested in an operant appetitive-to-aversive transfer task. We hypothesized that NBM lesions would not affect performance in the appetitive phase, but that performance would be impaired during subsequent transfer to the aversive phase of the task. Additional groups of NBM lesion and control rats were tested in the avoidance condition only, where we hypothesized that NBM lesions would not disrupt performance. These hypotheses were based on the argument that the NBM is not necessary for simple association learning that does not tax attention. Both the appetitive phase of the transfer task and the avoidance only task depend only on simple associative learning and are argued not to tax attention. Consequently, performance in these tasks was predicted to be spared following NBM lesions. Complex, attention-demanding associative learning, however, is argued to depend on the NBM. Performance in the aversive phase of the transfer task is both attentionally demanding and associatively more complex than in either the appetitive or aversive tasks alone; thus, avoidance performance in the NBM lesion group was predicted to be impaired following transfer from prior appetitive conditioning. Results supported our hypotheses, with the NBM lesion group acquiring the appetitive response normally, but showing impaired performance following transfer to the aversive conditioning phase of the transfer task. Impairments were not attributable to disrupted avoidance learning per se, as avoidance behavior was normal in the NBM lesion group tested in the avoidance condition only.


Assuntos
Comportamento Apetitivo/fisiologia , Aprendizagem por Associação/fisiologia , Aprendizagem da Esquiva/fisiologia , Núcleo Basal de Meynert/fisiologia , Transferência de Experiência/fisiologia , Análise de Variância , Animais , Atenção/fisiologia , Condicionamento Operante/fisiologia , Masculino , Distribuição Aleatória , Ratos , Ratos Long-Evans
18.
Toxicol Pathol ; 29(6): 600-6, 2001.
Artigo em Inglês | MEDLINE | ID: mdl-11794375

RESUMO

Few studies have examined the carcinogenicity of chemicals toward the urinary bladder in hamsters, and the effect of diet on hamster urine and urothelium has not been reported. Our laboratory recently began investigating the effects of dimethylarsinic acid (DMA) on the hamster bladder, and we noticed subtle urothelial changes even in controls. The possible effect of various diets on hamster urothelium was evaluated by feeding different diets to 4-week-old Syrian Golden hamsters for 5 weeks. The diets examined were Tekland 8656, Purina 5002, Purina 5L79, and NIH-07. Light microscopic examination showed a slight increase in urothelial hyperplasia in hamsters fed Purina 5L79. An increase in the incidence of urinary bladder necrosis, exfoliation, and mild hyperplasia were noted by scanning electron microscopy (SEM) with all dietary preparations except NIH-07. The constituents in the diets producing the urothelial alterations are not known at present, but NIH-07 diet was chosen for experiments to investigate the effects of DMA on the hamster bladder epithelium. Male and female 5-week-old Syrian Golden hamsters were fed 100 ppm DMA for 10 weeks. Examination of urinary parameters showed no treatment-related changes. Light microscopic examination and SEM revealed no changes of the urothelium of DMA-treated male or female hamsters.


Assuntos
Ácido Cacodílico/toxicidade , Herbicidas/toxicidade , Bexiga Urinária/efeitos dos fármacos , Animais , Peso Corporal/efeitos dos fármacos , Cricetinae , Dieta , Ingestão de Líquidos/efeitos dos fármacos , Feminino , Hiperplasia , Masculino , Mesocricetus , Microscopia Eletrônica de Varredura , Tamanho do Órgão , Bexiga Urinária/ultraestrutura , Urina/química , Urotélio/efeitos dos fármacos , Urotélio/patologia , Urotélio/ultraestrutura
19.
J Nutr ; 127(5 Suppl): 826S-829S, 1997 05.
Artigo em Inglês | MEDLINE | ID: mdl-9164246

RESUMO

Urine plays a major role in bladder carcinogenesis, acting as a transport mechanism for carcinogens, containing several growth factors stimulating cell proliferation, and indirectly affecting chemicals by alterations in concentrations of normal urinary components such as electrolytes, water and proteins. These latter effects are greatly modified by diet composition and consumption and also by water consumption. Several examples of these effects are presented.


Assuntos
Anticarcinógenos , Carcinógenos , Dieta , Neoplasias da Bexiga Urinária/induzido quimicamente , Neoplasias da Bexiga Urinária/prevenção & controle , Animais , Humanos , Mutagênicos , Sacarina/efeitos adversos
20.
Proc Soc Exp Biol Med ; 220(3): 169-77, 1999 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-10193445

RESUMO

The objective of this study is to test the hypothesis that members of the pregnancy-specific beta 1-glycoprotein (PSG) family enhance the growth and maturation of embryos. cDNA encoding two members of the PSG family, namely PSG1 and PSG3, were expressed in Chinese Hamster Ovary (CHO) cells with the expression vector pH beta APr-1-neo. Two-cell stage mouse embryos were co-cultured in a two-chamber system with CHO cells expressing either recombinant PSG1 (rPSG1) or PSG3 (rPSG3) in the presence and absence of neutralizing PSG antibodies. The cleavage and maturation stage of the embryos was assessed at 12-hr intervals. Mouse embryos co-cultured with transfectants expressing rPSG1 showed a significant enhancement of cleavage and maturation rate compared to controls with P < 0.005-0.004. In co-cultures with CHO cells expressing rPSG3, no significant difference from the controls was observed in the early stage of development until late blastocyst formation. At that stage, there was a statistically significant enhancement of development by rPSG3 when compared to controls with P < 0.001. These results suggest that PSG1 and PSG3 exhibit embryotropic activity at different stages of development in the mouse model.


Assuntos
Desenvolvimento Embrionário e Fetal/efeitos dos fármacos , Glicoproteínas beta 1 Específicas da Gravidez/farmacologia , Animais , Blastocisto/efeitos dos fármacos , Células CHO , Fase de Clivagem do Zigoto/efeitos dos fármacos , Técnicas de Cocultura , Cricetinae , Desenvolvimento Embrionário e Fetal/fisiologia , Feminino , Humanos , Camundongos , Mórula/efeitos dos fármacos , Testes de Neutralização , Gravidez , Glicoproteínas beta 1 Específicas da Gravidez/genética , Glicoproteínas beta 1 Específicas da Gravidez/fisiologia , Proteínas Recombinantes/genética , Proteínas Recombinantes/farmacologia , Transfecção
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