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Biomedical subjects

F Hata

Publications and source records attributed to F Hata.

At least 109 records · Page 6Linked to original sources

Clinical application of hair protein glycation in the assessment of blood glucose control and diabetic neuropathy.

Glycation of hair protein was assessed in diabetic patients by the measurement of furosine, which is derived from fructose-lysine, a glycated lysine residue in protein. The level of furosine in 12-cm-long hair which grew over the course of one year was significantly better correlated with the mean values of four determinations of fasting plasma glucose (FPG) and four determinations of hemoglobin A1c, respectively, at the time of hair sampling. The level of glycation in hair, which corresponds to the time taken for hair growth, may represent the mean level of blood glucose during the time corresponding to the growth period. The values of motor nerve conduction velocity and sensory nerve conduction velocity were better correlated with the level of furosine in hair corresponding in the length to 1 year's growth than the levels of FPG and hemoglobin A1c at the time of the determination of nerve conduction velocity. These results suggest that hair glycation may serve as a valuable indicator both of long-term blood glucose trends and of the relationship between diabetic complications and blood glucose.

Adult↗

The effect of fructose on collagen glycation.

The effect of fructose on the formation of advanced Maillard reaction products which have fluorescence and cross-links was investigated. Type I collagen was added to various concentrations of glucose and fructose which were then incubated at 37 C for 4 weeks. Both the level of furosine and the fluorescence intensity increased in direct proportion to glucose and fructose levels and to the duration of incubation. Incubation with fructose produced less furosine but more intense fluorescence than incubation with glucose. These results suggest that fructose in the polyol pathway plays an important role in the formation of advanced Maillard products.

Animals↗

Skin blood flow in diabetic patients during cold loading.

We measured periflux blood flow (PBF) in people's fingers and its response to cold loading with a laser Doppler flowmeter. As an index in the cold loading test we used cold recovery time (CRT). Among normal people, CRT increased with age. Diabetics had significantly longer CRTs than did age-matched controls. CRT seems to be useful for evaluating the skin microcirculation in diabetics and the aged.

Adolescent↗

Effect of aminoguanidine on the glycation.

3-Deoxyglucosone, a carbonyl intermediate compound in the Maillard reaction, acts on bovine serum albumin to increase its fluorescence. Aminoguanidine inhibited the increase of fluorescence intensity formed by bovine serum albumin and 3-deoxyglucosone when 3-deoxyglucosone had been preincubated with aminoguanidine. These results suggested that aminoguanidine inhibits the action of 3-deoxyglucosone in the Maillard reaction.

Animals↗

Hair protein glycation as a long-term index of blood glucose in diabetics.

We used furosine, which is derived from fructose-lysine and is a glycation product, to measure the extent of hair protein glycation in diabetic patients. We took hair samples that were 12 cm long, corresponding roughly to 1 year's growth. While the furosine levels in these samples correlated poorly with fasting plasma glucose (FPG) and with hemoglobin A1c (HbA1c) levels at the time of sampling, better correlations were observed between glycation and the year-long average values of FPG, HbA1c, and the conduction velocities in two peripheral nerves. The glycation levels in these samples may thus reflect the year-long average of the patient's blood glucose. Hair glycation may serve as a valuable indicator both of long-term blood glucose trends and of the relationship between diabetic complications and blood glucose.

Adult↗

Glycation of cataractous lens in non-diabetic senile subjects and in diabetic patients.

Early- and advanced-stage products in the Maillard reaction, glycation, were measured in patients with diabetic or senile cataracts. Early-stage products were measured by means of furosine, which is an acid-hydrolysis product derived from fructose-lysine. Advanced-stage products were measured by fluorometry using high-performance liquid chromatography. Furosine levels were high (listed in descending order) in capsule, cortex and nucleus in both diabetic and senile cataracts. The advanced-stage products were also high (listed in descending order) in nucleus, cortex and capsule in both diabetic and senile cataracts. These results suggest that advanced-stage products might accumulate in larger amounts in the nucleus and cortex than in the capsule, resulting in the formation of cataracts. The study also revealed that the Maillard reaction plays an important role in causing not only diabetic cataracts but also senile cataracts.

Aged↗

A study of the age-related acceleration of glycation of tissue proteins in rats.

The relationship between age-related glycation and a fluorescent product attributable to the advanced Maillard reaction was investigated in the aortas of rats between 4 and 120 weeks of age. The early-stage product of the Maillard reaction was measured using furosine (epsilon-N-(2-furoylmethyl)-L-lysine) as a marker. The advanced product was measured by fluorescence high-performance liquid chromatography. The level of furosine in the aorta increased with aging to reach a maximum value in rats of 50 to 70 weeks of age, and decreased in rats from 90 to 120 weeks of age. By contrast, the level of the putative advanced product reached a maximum in 90-week-old rats and remained at the maximum level in 120-week-old rats. The level of glycated hemoglobin showed no significant change in rats of more than 14 weeks of age. The advanced Maillard products may play an important role in the pathophysiology of aging arteries.

Aging↗

Dual effects of clonidine on amylase secretory responses of rat parotid tissue induced by beta- and alpha 1-agonists.

The effects of clonidine on the amylase secretory responses of rat parotid tissue were examined in vitro. Clonidine increased amylase secretion induced by the beta-adrenergic agonist isoproterenol and decreased that induced by the alpha 1-adrenergic agonist methoxamine or phenylephrine with propranolol. Clonidine itself had no significant effect on the secretion. Yohimbine prevented the effects of clonidine on the secretions induced by both adrenergic agonists. Clonidine did not have any significant effect on cyclic AMP accumulation in the tissues induced by the beta-adrenergic agonist. The parotid tissue after reserpine treatment exhibited supersensitivity to beta- and alpha 1-adrenergic agonists. In reserpine treated tissues, the stimulatory effect of clonidine on beta-agonist-induced secretion disappeared, but the inhibitory effect on alpha 1-agonist-induced secretion remained unchanged. Similar results were obtained after sympathectomy of the gland. These data suggest that the inhibitory effect of clonidine on alpha 1-agonist-induced secretion is related to a postsynaptic site, whereas its effect on beta-agonist-induced secretion is still unknown.

Acetylcholine↗

Glycation of hair protein in the assessment of long-term control of blood glucose.

Glycation of hair protein was assessed in diabetic patients by the measurement of furosine, which is derived from fructose-lysine, a glycated lysine residue in protein. The level of furosine in 12-cm-long hair which grew over the course of one year was significantly better correlated with the mean values of four determinations of fasting plasma glucose (FPG) and four determinations of hemoglobin A1c (HbA1c) performed at three-month intervals than with FPG and the level of HbA1c, respectively, at the time of hair sampling. The level of glycation in hair, which corresponds to the time taken for hair growth, may represent the mean level of blood glucose during the time corresponding to the growth period. These results suggest that the determination of glycation in hair may be useful as an indicator of long-term control of blood glucose levels if appropriate lengths of hair are taken from the scalp.

Adult↗

Accelerated glycation of the aorta in diabetic rats.

Glycation of the aorta in rats with streptozotocin-induced diabetes was estimated by determining the early-stage product and the advanced product of the Maillard reaction. The early-stage product of the Maillard reaction was determined using furosine, which is derived from glycated lysine residues by acid hydrolysis. The advanced product was determined by fluorescence high-performance liquid chromatography. The levels of both early-stage and advanced products in diabetic rats were significantly higher than those in non-diabetic rats at the age of both 20 and 50 weeks. The levels of both early-stage and advanced products at 50 weeks in rats tended to be higher than those at 20 weeks. However, the level of glycated hemoglobin in both non-diabetic and diabetic rats showed no significant change between 20 and 50 weeks of age. These results suggest that tissue glycation may be involved in the development of diabetic complications and may be related to the aging mechanism.

Animals↗