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1.
Science ; 372(6545): 980-983, 2021 05 28.
Artigo em Inglês | MEDLINE | ID: mdl-34045354

RESUMO

Climate change and other human activities are causing profound effects on marine ecosystem productivity. We show that the breeding success of seabirds is tracking hemispheric differences in ocean warming and human impacts, with the strongest effects on fish-eating, surface-foraging species in the north. Hemispheric asymmetry suggests the need for ocean management at hemispheric scales. For the north, tactical, climate-based recovery plans for forage fish resources are needed to recover seabird breeding productivity. In the south, lower-magnitude change in seabird productivity presents opportunities for strategic management approaches such as large marine protected areas to sustain food webs and maintain predator productivity. Global monitoring of seabird productivity enables the detection of ecosystem change in remote regions and contributes to our understanding of marine climate impacts on ecosystems.

2.
Environ Toxicol Chem ; 38(1): 106-114, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-30284322

RESUMO

Physical systems, such as currents and winds, have traditionally been considered responsible for transporting contaminants. Although evidence is mounting that animals play a role in this process through their movements, we still know little about how such contaminant biotransport occurs and the extent of effects at deposition sites. In the present study, we address this question by studying how rhinoceros auklets (Cerorhinca monocerata), a seabird that occurs in immense colonies (∼300 000 pairs at our study site, Teuri Island), affect contaminant levels at their colony and at nearby sites. More specifically, we hypothesize that contaminants are transported and deposited by seabirds at their colony and that these contaminants are passed on locally to the terrestrial ecosystem. To test this hypothesis, we analyzed the concentration of 9 heavy metal and metalloids, as well as δ13 C and δ15 N stable isotopes, in bird tissues, plants, and soil, both within and outside of the colony. The results show that rhinoceros auklets transport marine-derived mercury (Hg), possibly from their wintering location, and deposit Hg via their feces at their breeding site, thereby contaminating plants and soils within the breeding colony. The present study confirms not only that animals can transport contaminants from marine to terrestrial ecosystems, potentially over unexpectedly long distances, but also that bird tissues contribute locally to plant contamination. Environ Toxicol Chem 2019;38:106-114. © 2018 SETAC.


Assuntos
Charadriiformes/metabolismo , Ecossistema , Metais/metabolismo , Água do Mar , Oligoelementos/metabolismo , Animais , Transporte Biológico , Monitoramento Ambiental , Eritrócitos/metabolismo , Fezes/química , Geografia , Ilhas , Isótopos de Mercúrio , Metaloides/metabolismo , Raízes de Plantas/metabolismo , Plantas/metabolismo , Análise de Componente Principal , Solo/química
3.
J Exp Biol ; 213(Pt 7): 1018-25, 2010 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-20228337

RESUMO

Species of bird that use their wings for underwater propulsion are thought to face evolutionary trade-offs between flight and diving, leading to the prediction that species with different wing areas relative to body mass (i.e. different wing loadings) also differ in the relative importance of flight and diving activity during foraging trips. We tested this hypothesis for two similarly sized species of Alcidae (common guillemots and razorbills) by using bird-borne devices to examine three-dimensional foraging behaviour at a single colony. Guillemots have 30% higher wing loading than razorbills and, in keeping with this difference, razorbills spent twice as long in flight as a proportion of trip duration whereas guillemots spent twice as long in diving activity. Razorbills made a large number of short, relatively shallow dives and spent little time in the bottom phase of the dive whereas guillemots made fewer dives but frequently attained depths suggesting that they were near the seabed (ca. 35-70 m). The bottom phase of dives by guillemots was relatively long, indicating that they spent considerable time searching for and pursuing prey. Guillemots also spent a greater proportion of each dive bout underwater and had faster rates of descent, indicating that they were more adept at maximising time for pursuit and capture of prey. These differences in foraging behaviour may partly reflect guillemots feeding their chicks single large prey obtained near the bottom and razorbills feeding their chicks multiple prey from the water column. Nonetheless, our data support the notion that interspecific differences in wing loadings of auks reflect an evolutionary trade-off between aerial and underwater locomotion.


Assuntos
Charadriiformes/fisiologia , Mergulho/fisiologia , Voo Animal/fisiologia , Asas de Animais/fisiologia , Animais , Comportamento Animal/fisiologia , Água do Mar , Fatores de Tempo , Suporte de Carga/fisiologia
4.
J Womens Health (Larchmt) ; 18(3): 303-10, 2009 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-19243271

RESUMO

OBJECTIVE: This study aimed to track the inclusion of women in clinical trials for new drugs approved by the Food and Drug Administration (FDA) between 2000 and 2002 and to evaluate the extent of analyses by sex. METHODS: Data were extracted from FDA reviewers' reports, summaries of clinical trials in New Drug Applications (NDAs), and product labeling and organized into a Microsoft Access database. The information collected includes subject enrollment by sex per clinical phase and sex differences in pharmacokinetics, safety, and efficacy as determined by either sponsors or reviewers. RESULTS: There were 67 New Molecular Entities (NMEs) approved by the FDA between 2000 and 2002. A total of 397,825 subjects were enrolled in 2,323 clinical trials. If 9 sex-specific NMEs are excluded, 297,697 subjects were enrolled in 1,974 clinical trials. Forty-seven percent of participants were male, 49% were female, and 4% of subjects were not specified. Of the 58 sex-nonspecific products in the study, 71% (41 of 58) of sex analyses were performed either by the sponsor or FDA reviewers. Twenty-five NMEs were found to have sex differences in pharmacokinetics, efficacy or adverse events. However, no recommendation was made to adjust dosage based on sex differences. CONCLUSIONS: The percentages of women and men participating in clinical trials varied by year, phase, and product type. However, the overall participation by women and men was comparable, suggesting an improvement in including more women in clinical trials when compared with the previous FDA study evaluating women's participation from 1995 through 1999. As with the previous study, however, a significant underrepresentation of women in early phase trials and in certain areas, such as cardiovascular products, was observed and continues to be an issue of concern. Lack of appropriate analyses by sex should also be noted as an issue of concern.


Assuntos
Ensaios Clínicos como Assunto/estatística & dados numéricos , Aprovação de Drogas/estatística & dados numéricos , Acessibilidade aos Serviços de Saúde/estatística & dados numéricos , Experimentação Humana/estatística & dados numéricos , Seleção de Pacientes , Adulto , Distribuição por Idade , Idoso , Feminino , Conhecimentos, Atitudes e Prática em Saúde , Humanos , Masculino , Pessoa de Meia-Idade , Distribuição por Sexo , Estados Unidos/epidemiologia , United States Food and Drug Administration , Saúde da Mulher , Adulto Jovem
5.
J Exp Biol ; 205(Pt 9): 1189-97, 2002 May.
Artigo em Inglês | MEDLINE | ID: mdl-11948196

RESUMO

Using a newly developed data logger to measure acceleration, we demonstrate that free-ranging king and Adélie penguins only beat their flippers substantially during the first part of descent or when they were presumed to be chasing prey at the bottom of dives. Flipper beating stopped during the latter part of ascent: at 29+/-9 % (mean +/- S.D.) of dive depth (mean dive depth=136.8+/-145.1 m, N=425 dives) in king penguins, and at 52+/-20 % of dive depth (mean dive depth=72.9+/-70.5 m, N=664 dives) in Adélie penguins. Propulsive swim speeds of both species were approximately 2 m s(-1) during dives; however, a marked increase in speed, up to approximately 2.9 m s(-1), sometimes occurred in king penguins during the passive ascending periods. During the prolonged ascending, oblique ascent angle and slowdown near the surface may represent one way to avoid the potential risk of decompression sickness. Biomechanical calculations for data from free-ranging king and Adélie penguins indicate that the air volume of the birds (respiratory system and plumage) can provide enough buoyancy for the passive ascent. When comparing the passive ascents for shallow and deep dives, there is a positive correlation between air volume and the depth of the dive. This suggests that penguins regulate their air volume to optimize the costs and benefits of buoyancy.


Assuntos
Aves/fisiologia , Mergulho/fisiologia , Ar , Animais , Fenômenos Biomecânicos , Medidas de Volume Pulmonar , Mecânica Respiratória , Especificidade da Espécie
6.
Chemosphere ; 44(6): 1375-82, 2001 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-11513115

RESUMO

Concentrations and patterns of several chlorinated persistent organic pollutants (POPs) including polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs) and biphenyls (PCBs) and DDTs, HCHs, CHLs and HCB were determined in black-tailed gulls (Larus crassirostris) from breeding grounds in Hokkaido, Japan. Subcutaneous fat of five adult gulls was analyzed, which had different concentrations of target compounds, whereas gull eggs contained similar concentrations of target compounds. Similar congener profiles were found between adult gulls and eggs. The concentrations of non-ortho PCBs varied from 3.4 to 13.5 ng/g lipid weight (lw) in the fat of black-tailed gulls and from 2.4 to 7.4 ng/g lw in their eggs. 2,3,7,8-PCDD/Fs occurred at relatively lower concentrations than non-ortho PCB congeners in both adult gulls and eggs. The total TEQs (toxic equivalents, PCDD/Fs+ non-ortho PCB) ranged from 0.26 to 1.0 ng/g lw in adult gulls and ranged from 0.19 to 0.58 ng/g lw in eggs.


Assuntos
Benzofuranos/farmacocinética , Aves , Poluentes Ambientais/farmacocinética , Inseticidas/farmacocinética , Bifenilos Policlorados/farmacocinética , Dibenzodioxinas Policloradas/análogos & derivados , Dibenzodioxinas Policloradas/farmacocinética , Poluentes do Solo/farmacocinética , Tecido Adiposo/química , Animais , Dibenzofuranos Policlorados , Ovos , Monitoramento Ambiental , Feminino , Masculino , Distribuição Tecidual
8.
J Forensic Sci ; 45(2): 478-82, 2000 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-10782978

RESUMO

We report a fatal case of death due to unusual aspiration of sardine fry in an elderly Japanese man with lung cancer. The cause of death was sudden respiratory arrest while eating. Autopsy revealed peculiar materials with cell nests and pigmented particles, together with striated muscle and skin, in the ectatic bronchioles of the left lower lobe. Serial histologic sections suggested that the structures observed were the eyeballs of small animals that appeared to have been inhaled. The patient had habitually eaten sardine fry and rice gruel, which were also detected in the gastric contents. Therefore, the eyes were considered to be those of the fry, which is a popular food item in Japan. This was confirmed by histologic examination of fry that were obtained commercially.


Assuntos
Produtos Pesqueiros , Corpos Estranhos/complicações , Neoplasias Pulmonares/complicações , Pneumonia Aspirativa , Idoso , Causas de Morte , Evolução Fatal , Medicina Legal , Humanos , Larva , Masculino
9.
J Clin Oncol ; 17(6): 1926-30, 1999 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-10561234

RESUMO

PURPOSE: To compare the effect of 5-hydroxytryptamine-3 (5HT(3)) receptor antagonists in cancer patients receiving chemotherapy including cisplatin (CDDP), with or without sustained-release oral morphine (MS Contin; Shionogi Co, Osaka, Japan). PATIENTS AND METHODS: We retrospectively studied 58 lung cancer patients given chemotherapy including at least 50 mg/m(2) CDDP with 5-HT(3) receptor antagonists between January 1996 and December 1997. Number of vomiting episodes, average proportions of hospital-supplied meals consumed (0 to 100%, as an index of appetite), and nausea severity scores (0 to 2 points, subjective patient judgment) were compared between oral morphine-administered (+) and morphine-free (-) groups. RESULTS: Sixteen morphine(+) and 42 morphine(-) cases were used. In cases of acute emesis (within 24 hours after CDDP injection), morphine(+) and morphine(-) groups were significantly different in number of vomiting episodes (1.25 and 0.14, respectively; P <.0001), appetite (58.13% and 90.24%; P <.0001), and nausea severity scores (1.63 and 0.62; P <.0001). In delayed-emesis cases (24 to 120 hours after CDDP), these groups differed significantly in number of vomiting episodes (1.94 and 0.43, respectively; P =.0001), appetite (23.13% and 52.08%; P <.0001), and nausea severity (1.38 and 0.91; P =.009). There were no significant differences in sex, age, anticancer drugs concurrent with CDDP, CDDP dose, corticosteroid administration, clinical stage, or type of 5-HT(3) antagonist. CONCLUSIONS: These data suggest that morphine can markedly reduce the effectiveness of 5-HT(3) receptor antagonists in patients receiving chemotherapy that includes CDDP. These results require confirmation by reinvestigation of clinical data on the efficacy of 5-HT(3) receptor antagonists and by extensive prospective analyses.


Assuntos
Cisplatino/efeitos adversos , Neoplasias Pulmonares/tratamento farmacológico , Morfina/farmacologia , Receptores de Serotonina/efeitos dos fármacos , Antagonistas da Serotonina/uso terapêutico , Vômito/tratamento farmacológico , Idoso , Relação Dose-Resposta a Droga , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Morfina/uso terapêutico , Receptores 5-HT3 de Serotonina , Estudos Retrospectivos , Fatores de Tempo , Vômito/induzido quimicamente
10.
Kansenshogaku Zasshi ; 73(8): 728-33, 1999 Aug.
Artigo em Japonês | MEDLINE | ID: mdl-10487017

RESUMO

In 14 subjects whose chest radiographs showed abnormal shadows during the two years from January 1995 until December 1996, no definite diagnosis could be obtained because sputum, smears and cultures all gave negative results for mycobacteria. Bronchoscopy was therefore performed, revealing atypical mycobacteria in cultures of the bronchial washing fluid for mycobacteria, and the significance of bronchoscopic examinations in cases diagnosed an atypical pulmonary mycobacteriosis was investigated. Most of the subjects (9) were women. Nine subjects had been informed that they had abnormal chest shadows; five had subjective symptoms; bloody sputum, 3 and cough, 2. The characteristics of the shadows were as follows: in the plain radiographs, the main shadows had a mottled or granular appearance in the majority of the patients (9) and there were infiltrative shadows in 3 patients and nodular shadows in another 3. In computed tomograms, the shadows in the vicinity of the pleura appeared as micronodular conglomerates in 12 patients, in 11 of whom bronchiectasis was also present near the shadows. Alveolar infiltrative shadows were present in four cases, and a cavity was seen in only one. Smears of the bronchial washing fluid for mycobacteria were positive in 7 patients, and cultures of this fluid yielded at least 100 colonies in 8 of the 14 subjects for whom the results were positive. By culture, Mycobacterium avium complex (MAC) was identified in 13 patients, but eleven of these in whom the bronchial washing fluid was concurrently tested for MAC by the polymerase chain reaction, only four were MAC-positive. Transbronchial lung biopsies were performed in 11 cases, in which the histological findings of mycobacterial infections showed granuloma in four, and caseation in three. Bronchoscopy is making possible initial-stage diagnosis, which are normally difficult, among the recently growing number of cases of the bronchial form of atypical pulmonary mycobacteriosis and is also useful for reaching definite diagnosis in the early stage.


Assuntos
Broncoscopia , Infecções por Mycobacterium não Tuberculosas/diagnóstico , Tuberculose Pulmonar/diagnóstico , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade
11.
C R Acad Sci III ; 322(7): 557-62, 1999 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-10488429

RESUMO

Cormorants feed by feet-propelled diving. How cormorants optimize foraging is of a particular interest in relation to the understanding of the feeding strategies of diving birds, as well as within the debate about cormorants' impact on sustainable resources. Using microdata loggers that recorded diving depth, we investigated the foraging strategy of males and females of subantarctic cormorants, which inhabit cold regions, and of Japanese cormorants, which live in the northern temperate zone. For both species, males and females daily spent the same amount of time submerged, and apparently captured the same amount of fish. However, males dived deeper and longer, which could be explained by their 15-20% larger body mass and may minimize potential competition for food.


Assuntos
Aves/fisiologia , Mergulho , Comportamento Alimentar , Locomoção , Animais , Regiões Antárticas , Feminino , Japão , Masculino , Caracteres Sexuais , Especificidade da Espécie
12.
Thorax ; 52(2): 125-9, 1997 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-9059471

RESUMO

BACKGROUND: It has previously been shown that fenoterol, a beta 2 adrenergic agonist, increases the ventilatory response to hypoxia (HVR) and hypercapnia (HCVR) in normal subjects. The effects of beta 2 adrenergic agonists on chemoreceptors in patients with chronic obstructive pulmonary disease (COPD) remain controversial. This study was designed to examine whether fenoterol increases the HVR and HCVR in patients with COPD. METHODS: The HCVR was tested in 20 patients using a rebreathing method and the HVR was examined using a progressive isocapnic hypoxic method. The HCVR and HVR were assessed by calculating the slopes of plots of occlusion pressure (P0.1) and ventilation (VE) against end tidal carbon dioxide pressure (PETCO2) and arterial oxygen saturation (SaO2), respectively. Spirometric values, lung volumes, and respiratory muscle strength were also measured. The HCVR and HVR were examined after the oral administration of fenoterol (15 mg/day) or placebo for seven days. RESULTS: Fenoterol treatment increased the forced expiratory volume in one second (FEV1) and inspiratory muscle strength. In the HCVR the slope of P0.1 versus PETCO2 was increased by fenoterol from 0.35 (0.23) to 0.43 (0.24) (p < 0.01). Moreover, the P0.1 at PETCO2 of 8 kPa was higher on fenoterol than on placebo (p < 0.05) and the VE was also greater (p < 0.01). In the HVR fenoterol treatment increased the P0.1 at 80% SaO2 from 0.90 (0.72) to 0.97 (0.55) kPa (p < 0.05) while the slopes of the response of P0.1 and VE were not changed. CONCLUSIONS: Fenoterol increases the ventilatory response to hypercapnia in patients with COPD, presumably by stimulation of the central chemoreceptor. The hypoxic ventilatory response is only slightly affected by fenoterol.


Assuntos
Agonistas Adrenérgicos beta/uso terapêutico , Fenoterol/uso terapêutico , Hipercapnia/fisiopatologia , Hipóxia/fisiopatologia , Pneumopatias Obstrutivas/tratamento farmacológico , Músculos Respiratórios/efeitos dos fármacos , Idoso , Idoso de 80 Anos ou mais , Células Quimiorreceptoras/efeitos dos fármacos , Estudos Cross-Over , Método Duplo-Cego , Feminino , Humanos , Pneumopatias Obstrutivas/fisiopatologia , Masculino , Pessoa de Meia-Idade , Músculos Respiratórios/fisiopatologia , Estimulação Química
13.
Thorax ; 50(2): 139-42, 1995 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-7701451

RESUMO

BACKGROUND: The effects of beta 2 adrenergic agonists on chemoreceptors remain controversial. This study was designed to examine whether fenoterol, a beta 2 adrenergic agonist, increases the ventilatory responses to hypercapnia (HCVR) and hypoxia (HVR) in normal subjects. METHODS: HCVR was tested with a rebreathing method and HVR was examined with a progressive isocapnic hypoxic method in 11 normal subjects. Both HCVR and HVR were assessed by the slope of occlusion pressure (P0.1) or ventilation (VE) plotted against end tidal carbon dioxide pressure and arterial oxygen saturation, respectively. Respiratory muscle strength, spirometric values and lung volume were measured. After a single oral administration of 5 mg fenoterol or placebo HCVR and HVR were evaluated. RESULTS: Fenoterol treatment did not change the specific airway conductance or forced expiratory volume in one second. Respiratory muscle strength did not change. Fenoterol increased the slope of the HCVR of both P0.1 (from 0.251 (0.116) to 0.386 (0.206) kPa/kPa, average increase 71%) and VE (from 10.7 (3.4) to 15.1 (4.2) l/min/kPa, average increase 52%), and shifted the response curves to higher values. For the HVR fenoterol increased the slopes of both P0.1 and VE (from -4.06 (2.00) x 10(-3) to -7.99 (4.29) x 10(-3) kPa/%, an average increase of 83%, and from -0.221 (0.070) to -0.313 (0.112) l/min/%, a 44.5% increase, respectively), and shifted the response curves to higher values. CONCLUSION: Acute administration of fenoterol increases the ventilatory responses to both hypercapnia and hypoxia in normal subjects.


Assuntos
Fenoterol/farmacologia , Hipercapnia/fisiopatologia , Hipóxia/fisiopatologia , Respiração/efeitos dos fármacos , Adulto , Método Duplo-Cego , Humanos , Masculino , Pessoa de Meia-Idade , Distribuição Aleatória
14.
Chest ; 106(3): 806-13, 1994 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-8082363

RESUMO

BACKGROUND: Emphysema diagnosed by computed tomography (CT) has been reported to be correlated with morphologic data from autopsied lungs or resected lobes. However, autopsied lungs or resected lobes are quite different from lungs in vivo. We examined the correlation between a quantitative analysis of CT and the in vivo morphologic degree of emphysema (selective alveolobronchography [SAB]) in patients with COPD. METHODS: We measured the mean attenuation value (MAV) of the lung fields between -700 HU and -1,024 HU to exclude the effect of high-density structures in 21 patients with COPD. Low attenuation, greater than 2 SD below the mean value of five normal healthy subjects, was used as an index of emphysema. To quantitate the amount of emphysema, the relative area of low attenuation to the area of the entire lung field (2SD percent) was measured. The morphologic degree of emphysema was determined from the diameter of ring shadow (DR) of SAB. We also examined the relationship between CT data and pulmonary function tests. RESULTS: The DR was highly correlated with the CT indexes of MAV and 2SD percent; (r = -0.894, p < 0.001, and r = 0.890, p < 0.001). Both MAV and 2SD percent were correlated with pulmonary function tests such as Dco, FEV1, and residual volume (r > 0.60). CONCLUSIONS: The MAV and relative area of emphysema obtained from CT density measurements accurately assess the severity of emphysema in patients with COPD as well as SAB.


Assuntos
Pulmão/diagnóstico por imagem , Pulmão/fisiopatologia , Enfisema Pulmonar/diagnóstico , Adulto , Idoso , Broncografia/instrumentação , Broncografia/métodos , Broncografia/estatística & dados numéricos , Doença Crônica , Feminino , Humanos , Análise dos Mínimos Quadrados , Masculino , Pessoa de Meia-Idade , Enfisema Pulmonar/epidemiologia , Testes de Função Respiratória/instrumentação , Testes de Função Respiratória/métodos , Testes de Função Respiratória/estatística & dados numéricos , Tomógrafos Computadorizados , Tomografia Computadorizada por Raios X/instrumentação , Tomografia Computadorizada por Raios X/métodos , Tomografia Computadorizada por Raios X/estatística & dados numéricos
15.
Nihon Kyobu Shikkan Gakkai Zasshi ; 31(10): 1337-40, 1993 Oct.
Artigo em Japonês | MEDLINE | ID: mdl-8271672

RESUMO

A 27-year-old female presented to our hospital because of anterior chest pain and left cervical tumor. Her chest X-ray film showed bilateral swelling of the superior mediastinum, which was composed of multiple mediastinal masses with obliteration of adjacent mediastinal fat on chest CT film. A specimen obtained from a left cervical lymph node histologically showed granuloma formation with central caseous necrosis, and the diagnosis of cervicomediastinal tuberculous lymphadenitis was therefore made. Both cervical tumor and mediastinal masses decreased in size following antituberculous chemotherapy. Mediastinal tuberculous lymphadenitis in young adults is rare. It is difficult to differentiate this condition from other mediastinal tumors, although its CT findings are characteristic.


Assuntos
Tuberculose dos Linfonodos/diagnóstico por imagem , Adulto , Diagnóstico Diferencial , Feminino , Humanos , Linfonodos/patologia , Mediastino , Pescoço , Tomografia Computadorizada por Raios X
16.
Br J Cancer ; 57(2): 170-3, 1988 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-3358907

RESUMO

When an antitumour mannoglucan prepared from Microellobosporia grisea, MGA was administered i.v. to C3H/He mice bearing the solid MH134 hepatoma, a cytotoxic factor was induced that was detectable in the tumour homogenate by an 8 h cytolysis assay against L-929 fibroblasts. Without MGA treatment, the cytotoxic factor was not detectable in the tumour homogenate. MGA induced the cytotoxic factor in tumour tissue specifically, its level reaching a maximum (24 U ml-1) 3 h after administration of MGA: little if any cytotoxic factor was detectable in homogenates of normal tissues or sera after MGA-treatment. The molecular size of the cytotoxic factor was estimated to be 70-80 kD by gel filtration. It seemed to be a type of tumour necrosis factor because its activity was inhibited by antiserum against murine tumour necrosis factor. From these results, the selective induction of the cytotoxic factor was concluded to be important in the mechanism of the antitumour activity of MGA.


Assuntos
Antibióticos Antineoplásicos/farmacologia , Glucanos/farmacologia , Neoplasias Hepáticas Experimentais/metabolismo , Polissacarídeos Bacterianos/farmacologia , Fator de Necrose Tumoral alfa/biossíntese , Animais , Sobrevivência Celular/efeitos dos fármacos , Cromatografia em Gel , Relação Dose-Resposta a Droga , Fibroblastos/efeitos dos fármacos , Masculino , Camundongos , Camundongos Endogâmicos C3H , Fator de Necrose Tumoral alfa/análise
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