RESUMEN
A competitive enzyme-linked immunosorbent assay suitable for the measurement of caffeine in plasma and serum has been developed. Sheep immunised with an immunogen prepared by coupling 7-(5-carboxypentyl)1,3-dimethylxanthine to egg albumin produced antibodies with little crossreactivity with the metabolites of caffeine. The enzyme label was prepared by coupling 7-(5-carboxypentyl)-1,3-dimethylxanthine to peroxidase using the mixed anhydride method. The assay, which has a sensitivity of 0.01 mumol/l, permits direct measurement of caffeine in plasma and serum samples. 50 plasma samples measured by ELISA and by an established radioimmunoassay showed a correlation of r = 0.97 (P less than 0.001).
Asunto(s)
Cafeína/sangre , Ensayo de Inmunoadsorción Enzimática , Humanos , Radioinmunoensayo , Reproducibilidad de los ResultadosRESUMEN
The natural killer (NK) cell susceptibility of hamster tumours exhibiting high and low levels of spontaneous metastasis in vivo was investigated. The parent cell line (HSV-2-333-2-26), which was weakly metastatic, and the NK-sensitive target line K562 were both sensitive to hamster natural killer cell activity. In contrast, 2 in vivo cloned sublines, designated met A and met B, exhibited a high level of spontaneous metastasis and were shown to be weakly or non-susceptible to hamster UK reactivity.
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Células Asesinas Naturales/inmunología , Metástasis de la Neoplasia , Neoplasias Experimentales/inmunología , Animales , Línea Celular , Transformación Celular Neoplásica , Transformación Celular Viral , Células Clonales/inmunología , Cricetinae , Neoplasias Pulmonares/secundario , Masculino , Mesocricetus , Trasplante de Neoplasias , Simplexvirus/fisiologíaRESUMEN
The virulence of five wild-type influenza A viruses and 14 recombinant viruses, prepared from the cold adapted A/Ann Arbor/6/60 virus and various wild-type viruses, was studied by two methods. Firstly, the viruses were inoculated into hamsters, and the titres present in the lungs and turbinates at 1, 3 and 4 days post-infection were measured. Secondly, the effect of five wild-type and ten recombinant viruses on the ciliated epithelium of in vitro hamster tracheal organ cultures was examined. The results obtained were assessed with reference to the known virulence of the viruses for human volunteers. The results showed that virus strains virulent for man grew to higher titres in hamster lungs and turbinates than attenuated strains; and that virulent strains destroyed the ciliary activity of hamster tracheal organ cultures more quickly and to a greater extent than attenuated strains. Comparison of the results with the known virulence of viruses tested for man suggests that the reduced ability of virus to grow in hamster lung tissue and the relatively little effect on ciliary activity may be used as markers of virus attenuation; however, the growth of virus in hamster turbinates overlaps for virulent and attenuated strains and therefore was not considered a useful marker of virulence.
Asunto(s)
Orthomyxoviridae/patogenicidad , Recombinación Genética , Animales , Cricetinae , Pulmón/microbiología , Mesocricetus , Orthomyxoviridae/genética , Factores de Tiempo , Tráquea/microbiología , Cornetes Nasales/microbiología , Virulencia , Cultivo de VirusRESUMEN
AIM: To elucidate the role of the p53 tumour suppressor gene in the pathogenesis of lip cancer. METHODS: Expression of p53 was evaluated immunocytochemically in a retrospective study of formalin fixed, paraffin wax embedded tissue. Five cases each of four types of lip lesions were studied; these comprised squamous cell carcinoma (SCC), solar keratosis (SK), chronic hyperplastic candidosis (CHC), and lichen planus (LP). Five cases each of normal lip mucosa, SCC, and SK from sun exposed facial skin as well as LP, CHC, and SCC from buccal mucosa were also analysed. Immunolocalisation of p53 was scored semiquantitatively. The degree of apoptosis was also assessed in selected lesions by determining cell nuclear fragmentation. RESULTS: All SCCs from lip lesions were immunopositive for p53. All cases of SK and two of five CHC lip lesions were also p53 positive. Normal lip mucosa samples were p53 negative. Sun exposed skin lesions of SCC and SK were all positive for p53, but only three of five cases of SCC from the buccal mucosa had detectable levels of p53. p53 expression was not detected in CHC and LP lesions of the buccal mucosa. CONCLUSIONS: The aberrant expression of p53 is likely to occur early in the pathogenesis of lip cancer and may be related to exposure to the sun. The immunopositive p53 cells identified in the benign LP lesions do not necessarily correlate with commitment of cells within the lesion to programmed cell death. In light of the prior reports which indicate that p53 positive cells may progress to form malignant tumours, it is suggested that patients with p53 positive but otherwise benign lesions should be followed more closely.
Asunto(s)
Carcinoma de Células Escamosas/metabolismo , Enfermedades de los Labios/etiología , Proteína p53 Supresora de Tumor/análisis , Biomarcadores/análisis , Carcinoma de Células Escamosas/genética , Estudios de Casos y Controles , Femenino , Expresión Génica/genética , Humanos , Inmunohistoquímica , Enfermedades de los Labios/patología , Neoplasias de los Labios/genética , Neoplasias de los Labios/metabolismo , Masculino , Estudios RetrospectivosRESUMEN
Administration of lipopolysaccharide to anaesthetised rats produced a reduction in mean arterial pressure, an increase in heart rate, and death at 4-6 h. Intravenous infusion of NG-nitro-L-arginine methyl ester (50 mg/kg), an inhibitor of constitutive and inducible nitric oxide (NO) synthase, 60 min after challenge with lipopolysaccharide, caused an immediate increase in blood pressure followed by a precipitous fall in pressure, and death. In contrast, intravenous infusion of L-canavanine (100 mg/kg), reported to be a selective inhibitor of inducible NO synthase in vitro, 60 min and 180 min after lipopolysaccharide challenge, produced an increase in mean arterial pressure and reversed the lipopolysaccharide induced hypotension. However, in lipopolysaccharide challenged animals protected from hypotension by administration of L-canavanine (60 min post challenge), intravenous infusion of NG-nitro-L-arginine methyl ester at 180 min post challenge caused an immediate rise in mean arterial pressure, followed by a rapid fall in blood pressure and heart rate, and sudden death. In contrast, a second dose of L-canavanine at 180 min post challenge maintained blood pressure for the duration of the experiment. These findings indicate that inhibition of both constitutive and inducible NO synthase during endotoxaemia is lethal. However, the use of a selective inhibitor of inducible NO synthase restores mean arterial pressure to baseline, and offers a therapeutic approach to managing hypotension in shock.
Asunto(s)
Presión Sanguínea/efectos de los fármacos , Canavanina/farmacología , Choque Séptico/fisiopatología , Aminoácido Oxidorreductasas/antagonistas & inhibidores , Aminoácido Oxidorreductasas/biosíntesis , Animales , Arginina/análogos & derivados , Arginina/farmacología , Inducción Enzimática/efectos de los fármacos , Escherichia coli , Frecuencia Cardíaca , Lipopolisacáridos/farmacología , Masculino , NG-Nitroarginina Metil Éster , Óxido Nítrico/antagonistas & inhibidores , Óxido Nítrico Sintasa , Ratas , Choque Séptico/inducido químicamente , Choque Séptico/enzimologíaRESUMEN
Plasma insulin-like growth factor 1 (IGF-1) concentrations were measured in a group of patients with hypoglycaemia due to endogenous hyperinsulinism, and compared with those in a group of patients matched for age and sex with hypoglycaemia and appropriately suppressed insulin levels. Insulin-like growth factor 1 concentrations were significantly higher in the hyperinsulinaemic hypoglycaemic group than in either the hypoinsulinaemic hypoglycaemia group or a group of euglycaemic control subjects. These data provide further evidence that insulin promotes IGF-1 production and release from the liver.
Asunto(s)
Hipoglucemia/sangre , Factor I del Crecimiento Similar a la Insulina/metabolismo , Somatomedinas/metabolismo , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Glucemia/metabolismo , Péptido C/sangre , Femenino , Humanos , Hiperinsulinismo/sangre , Hiperinsulinismo/complicaciones , Hipoglucemia/etiología , Insulina/sangre , Masculino , Persona de Mediana EdadRESUMEN
Nonidentical twin male infants (twin 1,950 g birth weight, twin 2,970 g) had their nutritional and hormone status studied for up to 59 days. Both infants received parenteral nutrition up to 32 days postnatally; enteral feeding was then established in twin 1; in twin 2 parenteral feeding was recommenced on day 35, for the remainder of the study. Serial 72-hr metabolic balances were performed in both infants at 4, 32, 45, and 56 days postnatally. Insulin-like growth factor I (IGF-I) and growth hormone were assayed on day 2 of each balance. During the course of the study growth was similar in each infant. Overall mean daily energy intakes were 90 kcal/kg/day and 84 kcal/kg/day and percentage nitrogen retention was 62% and 55% in twin 1 and twin 2, respectively. No differences were observed between the two infants in IGF-I or growth hormone. Despite low energy intakes incremental weights were within an acceptable range for both infants.
Asunto(s)
Nutrición Enteral , Recién Nacido de Bajo Peso/metabolismo , Estado Nutricional , Nutrición Parenteral , Gemelos Dicigóticos , Ingestión de Energía , Hormona del Crecimiento/análisis , Humanos , Recién Nacido , Factor I del Crecimiento Similar a la Insulina/análisis , Estudios Longitudinales , Masculino , Nitrógeno/administración & dosificación , Nitrógeno/metabolismoAsunto(s)
Etanol/farmacología , Osteocalcina/sangre , Adulto , Calcio/sangre , Ritmo Circadiano , Humanos , Masculino , Fosfatos/sangreRESUMEN
Impairment of driving skills by drugs is an important cause of traffic accidents. Alcohol is the most important, though far from the only, drug involved; and of 684 fatal accidents investigated by Woodhouse, 321 (47%) of the drivers had blood-alcohol levels greater than 100 mg/100 ml at the time of death. In 16 it exceeded 400 mg/100 ml. Unlike alcohol, cannabis has received little attention as a possible cause of traffic accidents, largely owing to the difficulty of proving cannabis use objectively. The recent development of a reliable and relatively simple method for detecting and measuring cannabis products in blood and urine may help to overcome this difficulty. As Milner has pointed out, the full effect of alcohol on driving competence was not appreciated until objective methods of measuring blood-alcohol levels became generally available. The same may be true of cannabis.
Asunto(s)
Accidentes de Tránsito , Conducción de Automóvil , Cannabis , Adulto , Autopsia , Cannabis/efectos adversos , Dronabinol/sangre , Dronabinol/orina , Inglaterra , Humanos , Masculino , RadioinmunoensayoRESUMEN
A spontaneously metastatic tumour of hamsters and cell lines derived from its in vivo metastatic deposits, or from in vitro cloning were compared for immunobiological and genotypic variation and correlation sought with regard to metastatic potential. Cell lines were established from seven individual lung metastases following primary tumour resection of the parent (HSV-2-333-2-26) cell line. When inoculated subcutaneously, and upon resection of the subsequent tumour mass, four cell lines (MetA, MetB, MetE and MetF) demonstrated greater, one similar (MetG) and two (MetC and MetD) less metastatic capacity compared with the parent tumour line. In further studies cell lines were established in vitro by single cell cloning of the parent tumour either by limiting dilution or soft agar cloning. In vivo tumour resection experiments showed eight cell lines (S4, S7, S4A, S7A, S7B, C1.1, C1.4 and C1.5) to have an increased metastatic potential and five cell lines (S8, S9, S8B, S9D and S9E) a decreased metastatic potential compared to the parental line. Karyotypic analysis of the cells revealed that all highly metastatic cell lines were of a near diploid genotype, whilst non- and weakly metastatic cell lines, including the parental line, were aneuploid or near tetraploid. The immunobiological characteristics of these cell lines was studied. Assessment of in vivo immunogenicity showed that eight clones (MetA, MetB, MetE, MetF, S7A, C1.1, C1.4 and C1.5) were non-immunogenic whilst the parental tumour line and three clones (MetC, MetD and MetG) exhibited a strong transplantation rejection antigen; immunogenicity showed an inverse correlation with metastatic potential. Susceptibility to NK cytolysis was demonstrated for cell lines exhibiting a weak or non-metastatic/immunogenic phenotype. The origin of metastatic variants and their association with genotype and immunobiological properties is discussed.
Asunto(s)
Fibrosarcoma/patología , Animales , Ciclo Celular , Línea Celular , Cricetinae , Fibrosarcoma/etiología , Fibrosarcoma/genética , Fibrosarcoma/inmunología , Genotipo , Cariotipificación , Células Asesinas Naturales/inmunología , Masculino , Mesocricetus , Metástasis de la Neoplasia , Fenotipo , Simplexvirus , Infecciones Tumorales por Virus/genética , Infecciones Tumorales por Virus/patologíaRESUMEN
Inhibition of nitric oxide synthesis was investigated in a murine model of advanced sepsis in which antibiotic therapy alone did not improve survival. Seven hours after receiving a lethal intraperitoneal challenge with live Escherichia coli, mice were given either NG-monomethyl-L-arginine (L-NMMA) intravenously, imipenem-cilastatin subcutaneously or a combination of both. L-NMMA (3-300 mg/kg) or imipenem-cilastatin (10 or 50 mg/kg) given alone did not improve survival; co-administration of L-NMMA and either 10 or 50 mg imipenem-cilastatin/kg improved survival significantly. These findings suggest that nitric oxide contributes to the morbidity associated with advanced sepsis and that nitric oxide synthase inhibition may improve the efficacy of conventional antimicrobial treatment of severe infections.
Asunto(s)
Aminoácido Oxidorreductasas/antagonistas & inhibidores , Arginina/análogos & derivados , Cilastatina/uso terapéutico , Imipenem/uso terapéutico , Peritonitis/tratamiento farmacológico , Animales , Arginina/uso terapéutico , Combinación Cilastatina e Imipenem , Modelos Animales de Enfermedad , Combinación de Medicamentos , Quimioterapia Combinada , Infecciones por Escherichia coli/tratamiento farmacológico , Infecciones por Escherichia coli/metabolismo , Masculino , Ratones , Óxido Nítrico Sintasa , Peritonitis/metabolismo , omega-N-MetilargininaRESUMEN
A radioimmunoassay specific for the closed, three-ringed cannabinoid nucleus was used to detect and measure caname from hospital inpatients not suspected of taking drugs. None of these contained tetrahydro-cannabinol cross-reacting cannabinoids (THC-CRC). The other 393 specimens were from patients known or suspected to be taking various drugs. Of these 51 out of 162 from one hospital treatment clinic and 19 out of 50 from another were positive for THC-CRC. Out of 107 urine specimens from an independent drug treatment clinic 71 were positive for THC-CRC, as were 13 out of 74 specimens from patients in whom drug misuse was suspected or thought possible.
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Cannabis/orina , Radioinmunoensayo/métodos , Dronabinol/orina , Humanos , Trastornos Relacionados con SustanciasRESUMEN
A direct radioimmunoassay in unextracted plasma is described. The assay has a sensitivity of 4 pmol/l (2 standard deviation from zero). The proinsulin antiserum was immuno-adsorbed against human C-peptide and insulin coupled to glass beads. Cross-reactivity of the antiserum was assessed and shown to be less than 0.01% with both peptides. In normal healthy fasting subjects the plasma proinsulin level was 6.7 +/- 1.7 pmol/l (n = 17) (mean +/- SD). Fasting proinsulin levels in non-insulin dependent diabetics were significantly elevated compared with non diabetics (14.2 +/- 2 pmol/l (n = 11) vs 6.7 +/- 1.7 (n = 17) P less than 0.005). The insulin/proinsulin ratio was 3.4:1 in the non-insulin dependent diabetic compared with 6:1 in non-diabetics. Samples from 21 insulinoma patients were assayed and mean fasting plasma proinsulin level was 255 pmol/l +/- 479 when the patients were hypoglycaemic. The range in pro-insulin levels was large (30-2300 pmol/l). Mean fasting proinsulin level in three hypoglycaemic subjects due to sulphonylurea overdose was 15.7 +/- 2.3 pmol/l. The molar ratio of proinsulin to insulin was 1:6 in healthy subjects, 1:1 in insulinoma patients and 10:1 in sulphonylurea induced hypoglycaemic patients.
Asunto(s)
Hipoglucemia/sangre , Proinsulina/sangre , Péptido C/sangre , Diabetes Mellitus Tipo 2/sangre , Humanos , Insulina/sangre , Insulinoma/sangre , Neoplasias Pancreáticas/sangre , Radioinmunoensayo , Sensibilidad y EspecificidadRESUMEN
The effect of basement membrane components (laminin, fibronectin and type IV collagen) and lung fibroblasts on type IV collagenase and plasminogen activator activity was investigated in a primary HSV-2-induced hamster fibrosarcoma, and its in vivo derived sublines and in vitro derived clones of varying metastatic potential. Fibronectin and type IV collagen were ineffective at influencing the expression of either type IV collagenase or plasminogen activator activity. Laminin, however, at concentrations of 1-10 micrograms ml-1 added to the serum-free culture supernatants, increased the release of type IV collagenase by up to 100% for the parental cell line. Three highly metastatic sublines (two from in vivo origin and one from in vitro cloning) showed increases of up to 300%. Non-metastatic sublines (two from in vivo origin and one from in vitro cloning), however, showed no increase in type IV collagenase activity. Plasminogen activator release from either the parental line cell or its metastatic sublines and clones, was unaffected by the addition of laminin. Addition of tumour cells to lung fibroblast monolayers resulted in an increased expression of PA activity in the supernatant, whilst type IV collagenase activity was reduced.
Asunto(s)
Membrana Basal/metabolismo , Fibrosarcoma/enzimología , Laminina/farmacología , Colagenasa Microbiana/metabolismo , Activadores Plasminogénicos/metabolismo , Animales , Línea Celular , Colágeno/farmacología , Cricetinae , Fibroblastos/enzimología , Fibronectinas/farmacología , Fibrosarcoma/secundario , Masculino , Mesocricetus , Metástasis de la Neoplasia/fisiopatología , Células Tumorales Cultivadas/efectos de los fármacos , Células Tumorales Cultivadas/enzimologíaRESUMEN
Subcutaneous injection of cortisone acetate administered with or without oral heparin retarded the growth of two HSV-2 induced hamster fibrosarcomas. Histological sections showed no obvious difference between the vasculature of treated and untreated tumours although there were fewer infiltrating lymphocytes in treated tumours. Treatment was, however, found to be ineffective against metastatic development following resection of primary tumours. Natural killer cell activity was found to be greatly reduced in animals receiving heparin and/or cortisone acetate treatment and this may influence the effectiveness of treatment on the metastatic process. We conclude that treatment of tumours with cortisone plus heparin is no different from the response to cortisone used alone.
Asunto(s)
Antineoplásicos/uso terapéutico , Cortisona/análogos & derivados , Fibrosarcoma/tratamiento farmacológico , Heparina/uso terapéutico , Neoplasias Experimentales/tratamiento farmacológico , Animales , Línea Celular , Cortisona/uso terapéutico , Cricetinae , Quimioterapia Combinada , Fibrosarcoma/etiología , Fibrosarcoma/patología , Células Asesinas Naturales/efectos de los fármacos , Masculino , Mesocricetus , Metástasis de la Neoplasia , Neoplasias Experimentales/etiología , Neoplasias Experimentales/patología , Infecciones Tumorales por Virus/tratamiento farmacológicoRESUMEN
The plasminogen activator (PA) content of a primary HSV-2-induced hamster fibrosarcoma and sublines derived from its in vivo metastases was investigated using the indirect 125I-labeled fibrin plate method. Fresh tissue culture lines established from primary HSV-2-333-2-26 tumors were shown to produce levels of PA similar to sublines derived from lung or kidney foci that developed after resection of primary tumors. In comparison, normal hamster embryo fibroblast (NHEF) and baby hamster kidney cells produced little or no PA, although baby hamster lung fibroblasts produced intermediate levels of PA. In addition, no correlation was found between PA levels of the sublines and their ability to metastasize from subcutaneous tumors, although tumor cell lines were shown to produce significantly more PA than normal cells.
Asunto(s)
Fibrosarcoma/metabolismo , Neoplasias Renales/secundario , Neoplasias Pulmonares/secundario , Neoplasias/metabolismo , Activadores Plasminogénicos/metabolismo , Animales , Línea Celular , Cricetinae , Fibrinólisis , Fibrosarcoma/patología , Fibrosarcoma/secundario , Neoplasias Renales/metabolismo , Neoplasias Pulmonares/metabolismo , Masculino , Mesocricetus , Metástasis de la Neoplasia , Factores de TiempoRESUMEN
The expression of a basement membrane (BM) collagen-degrading metalloprotease (Type IV collagenase) was studied in a herpes simplex virus (HSV)-2 transformed hamster fibrosarcoma and its in vivo derived sublines and in vitro derived clones of varying metastatic potential. The primary parent tumor was shown to release more or less Type IV collagenolytic activity compared with its sublines (derived from lung nodules that developed after resection of the primary tumor). Normal baby hamster kidney and hamster embryo fibroblasts did not secrete detectable amounts of BM collagenase, whereas normal hamster lung fibroblast secreted intermediate levels of Type IV collagenase activity. The collagenase IV activity of the parent tumor and its in vivo and in vitro derived sublines was assayed in vitro and compared with the ability of the cells lines to spontaneously metastasize in vivo. No correlation between the ability to secrete type IV collagenase and metastatic propensity was detected. Although all cell lines secreted type IV collagenase, the highest activity was recorded for a nonmetastatic variant.
Asunto(s)
Fibrosarcoma/enzimología , Colagenasa Microbiana/metabolismo , Metástasis de la Neoplasia , Animales , Membrana Basal/enzimología , Línea Celular , Transformación Celular Viral , Cricetinae , Medios de Cultivo , Activación Enzimática , Fibrosarcoma/microbiología , Fibrosarcoma/patología , Masculino , Mesocricetus , SimplexvirusRESUMEN
Osteoporosis is more common in chronic alcoholics than in age-matched controls. Possible aetiological factors are: malabsorption of calcium and vitamin D; liver disease and abnormal parathyroid function. The possibility that alcohol may directly affect osteoblastic function has, however, received little attention. We measured plasma osteocalcin, a protein synthesised specifically by osteoblasts, in chronic alcoholics. Our data show that these have low plasma osteocalcin but normal calcium, magnesium and parathormone, which suggest that alcohol may be directly toxic to osteoblasts.
Asunto(s)
Alcoholismo/complicaciones , Proteínas de Unión al Calcio/sangre , Osteoporosis/sangre , Adulto , Anciano , Consumo de Bebidas Alcohólicas/fisiología , Alcoholismo/sangre , Huesos/metabolismo , Femenino , Humanos , Masculino , Persona de Mediana Edad , OsteocalcinaRESUMEN
BACKGROUND: The insulinotropic hormones, glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (7-36 amide) (GLP-1), regulate insulin secretion to nutrient intake and constitute the endocrine arm of the entero-insular axis. Glucagon has been implicated in the pathophysiology of conditions characterised by abnormal glucose tolerance such as obesity and diabetes mellitus although its effect on the entero-insular axis is not fully understood. Materials and methods We investigated the effect of exogenous glucagon on the entero-insular axis and its relation to gastric emptying in six healthy men aged [mean (+/-S.E.M. )] 23.6 (0.9) years with a body mass index of 24.0 (1.5) kg/m(2). Plasma glucose, GIP, GLP-1, insulin and paracetamol concentrations were measured before and after a 100 g oral carhohydrate load containing 1.5 g of paracetamol for 6 h during intravenous infusion of either glucagon or saline. RESULTS: When compared to the saline infusion, peak and integrated insulin and glucose concentrations were higher (p<0.05) following glucagon infusion. After 60 min paracetamol concentrations were lower (p<0.05) following glucagon infusion. Integrated responses for GIP and GLP-1 were markedly reduced following glucagon infusion. CONCLUSIONS: Exogenous glucagon in addition to its well-documented action of increasing glucose and insulin concentrations and delaying gastric emptying also markedly reduces GIP and GLP-1 secretion. The inhibition of GLP-1 soon after commencement of glucagon infusion supports a direct effect of glucagon on intestinal L-cells. We speculate that the marked inhibition of postprandial GLP-1 secretion by glucagon may be of importance in the pathogenesis of relative insulinopenia in Type 2 diabetes and in the development of reduced satiety in obesity and diabetes.
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Carbohidratos/fisiología , Polipéptido Inhibidor Gástrico/sangre , Fármacos Gastrointestinales/farmacología , Glucagón/sangre , Glucagón/farmacología , Fragmentos de Péptidos/sangre , Precursores de Proteínas/sangre , Acetaminofén/farmacología , Adulto , Analgésicos no Narcóticos/farmacología , Glucemia/metabolismo , Vaciamiento Gástrico/efectos de los fármacos , Fármacos Gastrointestinales/sangre , Péptido 1 Similar al Glucagón , Glucosa/farmacología , Humanos , Insulina/sangre , Masculino , Proyectos Piloto , Método Simple CiegoRESUMEN
Natural killer (NK) cell activity was observed in the peripheral blood and spleen of 8- to 10-week-old Syrian golden hamsters, but not in the bone marrow or thymus. Low, but significant, levels of cytotoxicity were also observed in mesenteric and axillary lymph nodes and cells harvested from the peritoneum. Cytotoxicity, in a 4-hr 51Cr-release assay, was found to be nylon wool non-adherent and was significantly reduced by treatment with trypsin or incubation at 37 degrees C for 18 hr. Natural cytotoxicity was shown to be low at 1 week of age, but increased to a maximum at 8 weeks and was maintained into old age. Correlation was observed between peripheral blood cytotoxicity and the presence of large, often granular, lymphocytes following fractionation of effector cells by Percoll discontinuous gradient separation. These findings are compared with previous studies in hamsters, where the results of longer-term cytotoxicity tests differ in some respects to those of the present study.