Identification of homologous biologically active sites on the N-terminal domain of laminin alpha chains.

Laminin, a multifunctional glycoprotein of the basement membrane, consists of three different subunits, alpha, beta, and gamma chains. To date, five different alpha chains have been identified. N-terminal domain VI in the alpha1 chain has various biological activities. Here we screened biologically active sequences on domain VI of the laminin alpha2, alpha3, and alpha5 chains using a large number of overlapping peptides. HT-1080 human fibrosarcoma cell attachment to the peptides was evaluated using peptide-coated plastic plates and peptide-conjugated Sepharose beads. We identified four cell adhesive sequences from laminin alpha2 chain domain VI, two sequences from the alpha3 chain, and two sequences from the laminin alpha5 chain. Sequences homologous to A13 (RQVFQVAYIIIKA, alpha1 chain 121-133) on all the alpha chains (FQIAYVIVKA, alpha2 chain 130-139; GQLFHVAYILIKF, alpha3 chain 96-108; FHVAYVLIKA, alpha5 chain 74-83) showed strong cell attachment activity. A5-16 (LENGEIVVSLVNGR, alpha5 chain 147-160) showed the strongest cell attachment activity in the plate assay, and the homologous peptide in the alpha3 chain promoted similar strong cell attachment activity. A5-16 and its homologous peptide in the alpha2 chain promoted moderate cell attachment, while the homologous peptide to A5-16 in the alpha1 chain did not show activity. A2-7 (SPSIKNGVEYHYV, alpha2 chain 108-120) showed cell attachment activity only in the plate assay, but homologous sequences in the alpha1, alpha3, and alpha5 chains did not promote activity. A2-7 promoted endothelial cell sprouting from aortic rings in vitro and melanoma colonization to murine lungs in vivo. However, none of the homologous peptides of A2-7 promoted experimental pulmonary metastasis by B16-BL6 melanoma cells. These results indicate that there are chain-specific active sites in domain VI of the laminin alpha chains, some of which contain conserved activities.

Stronger suppression of plasma cholesterol and enhancement of the fecal excretion of steroids by a buckwheat protein product than by a soy protein isolate in rats fed on a cholesterol-free diet.

We investigated the effects of a buckwheat protein product (BWP), soy protein isolate (SPI) and casein on the plasma cholesterol level and fecal steroid excretion in rats fed on a cholesterol-free diet. The consumption of BWP suppressed plasma cholesterol by enhancing the fecal excretion of both neutral and acidic steroids. These effects of BWP were stronger than those of SPI.

A buckwheat protein product suppresses gallstone formation and plasma cholesterol more strongly than soy protein isolate in hamsters.

This study was conducted to investigate the effects of a buckwheat protein product (BWP) on plasma cholesterol, gallbladder bile composition and fecal steroid excretion in hamsters fed diets with 5 g/kg cholesterol. Diets also contained 200 g/kg of casein, soy protein isolate (SPI) or BWP as protein sources. After 2 wk, plasma and liver concentrations of cholesterol in the hamsters fed BWP were significantly lower than those in the hamsters fed casein and SPI. The molar proportion of cholesterol in gallbladder bile was significantly lower in the BWP group than in the other groups, whereas that of bile acids was slightly higher in the BWP group (P

Hypothalamic-pituitary-adrenal axis function in chronic schizophrenia: association with clinical features.

The function of the hypothalamic-pituitary-adrenal axis (HPA-axis) and its association with clinical features in chronic schizophrenia were investigated. Twenty of 33 chronic schizophrenics exhibited an abnormal diurnal variation of the saliva cortisol level. The patients with abnormal diurnal variation gave higher scores for some negative symptoms than those with normal diurnal variation. On the dexamethasone suppression test (DST) of saliva samples, 13 of 34 chronic schizophrenics were abnormal. The patients with DST nonsuppression were more frequently classified into disorganized type and exhibited low scores of anxiety compared with the patients with normal suppression. The 9 patients who showed abnormal diurnal variation and DST nonsuppression were more frequently classified into disorganized type and showed higher scores of negative symptoms than the 9 patients who did not show any abnormal cortisol data. These results suggest that there might be some disturbance in the function of the HPA-axis in a group of chronic schizophrenics and that these patients might have severe negative symptoms.

Dexamethasone suppression test in schizophrenia: its relation to monoamine metabolism in hypothalamic-pituitary-adrenal axis.

The metabolic disturbances of monoamine in the hypothalamic-pituitary-adrenal axis (HPA axis) was examined in patients with chronic schizophrenia showing nonsuppression of the dexamethasone suppression test (DST). Subjects were 16 male chronic schizophrenics consisting of 8 DST suppressors and 8 nonsuppressors. All the patients were orally given the 5HT precursor, L-5-hydroxytryptophan (L-5HTP, 3 mg/kg) and the alpha 2-adrenergic agonist, clonidine (3 micrograms/kg), and the concentrations of plasma prolactin, cortisol, human growth hormone, and blood 5HT were measured chronologically. As a result, all of the DST nonsuppressors showed no increased response of prolactin after L-5HTP loading. Moreover, in the DST nonsuppressors, the secretion response of cortisol after L-5HTP loading was delayed compared with that of the suppressors. However, no different response between the DST suppressors and the nonsuppressors was observed after a loading dose of clonidine. These results suggest that there might be a metabolic disturbance of 5HT in the HPA axis of chronic schizophrenics showing DST nonsuppression.

The diurnal variation and response to dexamethasone suppression test of saliva cortisol level in autistic children.

In order to examine the function of hypothalamic-pituitary-adrenal axis (HPA-axis) in autistic children, the diurnal rhythm of saliva cortisol and the response of cortisol to the DST was investigated using saliva samples. 1) The plasma and saliva cortisol levels showed a positive correlation in normal healthy adults. Moreover, the saliva cortisol level exhibited a similar diurnal rhythm and DST response as did the plasma cortisol level. 2) The saliva cortisol level in normal children showed a similar diurnal rhythm and DST response as that in normal healthy adults. 3) Some children with infantile autism showed an abnormal diurnal rhythm or DST response for saliva cortisol. Moreover, the latter abnormality was observed more frequently in poorly-developed cases than in highly-developed cases. 4) These results suggest that the negative feedback mechanism of the HPA-axis may be disturbed in autistic children, especially the poorly-developed cases, owing to a disorder in the regulation by serotonin metabolism.

Dexamethasone suppression test in autistic children.

A dexamethasone suppression test (DST) was carried out on autistic and other handicapped children to investigate the function of the hypothalamo-pituitary adrenal axis (HPA-axis). The subjects were 19 autistic children consisting of 11 relatively well-developed and eight poorly-developed children. The control groups were 26 normal volunteers, 19 patients with schizophrenia and 15 children with mental retardation (MR) or minimal brain dysfunction (MBD). The DST procedures followed the Carroll method. As a result, all of the normal volunteers and 19 schizophrenic patients showed normal response (suppressor). Nine of the 11 well-developed autistic children exhibited suppressor, while all of the poorly-developed children showed an abnormal response (non-suppressor). Nine of the 10 children with MR and all of the five children with MBD were suppressor. These results suggest that there might be a dysfunction in the HPA-axis of the poorly-developed autistic children.