Showing papers by "Shigehiro Katayama published in 1991"
TL;DR: The measurement of serum or urinary levels of type IV collagen may be a useful indicator for monitoring the development of diabetic microangiopathy, especially in early diabetic nephropathy.
12 citations
TL;DR: The results suggest that the increased production of type IV collagen may contribute to the thickening of basement membranes and may be linked to the development of diabetic nephropathy.
8 citations
TL;DR: The results suggest that SCT administration at a high dose may induce the formation of pituitary adenoma, or may accelerate the development of spontaneous pituitarian adenomas, some of which show frequent mitotic figures and invasive growth into the surrounding tissue, possibly resulting in malignant transformation.
Abstract: Calcitonin is widely used in the treatment of post-menopausal osteoporosis. The present study was designed to investigate the effects of salmon calcitonin (SCT) on the incidence of the pituitary tumors in Sprague-Dawley (SD) rats. Subcutaneous injections of SCT at a dose of 160 IU/kg/day for 6 months reduced body weight and induced one pituitary hyperplasia and three pituitary adenomas in 4 of 5 animals, while 5 controls did not show any changes. Prolactin-positive cells were located at the periphery of the affected pituitaries adjacent to the prolactin-negative adenomas. In addition, serum concentrations of prolactin and TSH were lower than in the controls, although serum calcium or LH levels were not significantly different from the controls. Among 7 animals treated with SCT for 6 months followed by no medication for another 6 months, 5 adenomas were detected, one of which had invasive growth toward the adjacent tissue, whereas only one adenoma was found in 9 controls. These results suggest that SCT administration at a high dose may induce the formation of pituitary adenoma, or may accelerate the development of spontaneous pituitary adenomas, some of which show frequent mitotic figures and invasive growth into the surrounding tissue, possibly resulting in malignant transformation. This indicates the need for caution in considering whether calcitonin injections into patients with osteoporosis as well as Paget's disease may induce such pituitary tumors.
8 citations
TL;DR: Serum levels of BGP and 1,25(OH)2D3 were significantly augmented along with a transient increase in urinary hydroxyproline excretion after Ca deprivation, suggesting that serum BGP is increased after one week of Ca restriction in healthy subjects.
Abstract: The present study was designed to clarify the effects of dietary calcium (Ca) intake on serum BGP (osteocalcin) levels. Twelve women with a mean age of 21.2 years participated in the study. After one week of normal Ca intake (mean±SE, 535±2mg/day), a low-Ca diet (163±1mg/day) was given for one further week. Additional asparagine Ca (3g as Ca/day) was also given to half of the subjects. Serum total and ionized Ca concentrations as well as BGP, PTH and 1, 25(OH)2D3 were measured at the end of each period. Amounts of Ca and hydroxyproline excreted in urine were also determined. The plasma level of ionized Ca was significantly increased without any change in total Ca in either group. Low and high Ca intake decreased and increased urinary Ca excretion by 28% and 56%, respectively. Serum levels of BGP and 1, 25(OH)2D3 were significantly augmente along with a transient increase in urinary hydroxyproline excretion after Ca deprivation. These results suggest that serum BGP is increased after one week of Ca restriction in healthy subjects.
5 citations
TL;DR: The results suggest that simple ABP monitoring throughout the day gives useful information to evaluate the severity of hypertension and the efficacy of antihypertensive medication as well as to avoid overtreatment with long-acting hypotensive agents resulting in a great fall in BP during sleep.
Abstract: Blood pressure (BP) obtained by the physician in his office and ambulatory BP recorded every hour throughout 24 hours with a noninvasive automated BP monitoring device were compared in 10 normotensives and 162 hypertensives. Casual BPs significantly correlated with averages in ambulatory BPs (ABPs) throughout the whole day, day (7 am - 10 pm) and night (0-5 am). However, it was noted that 6 of 10 normotensives and all of the moderate to severe hypertensives had ABPs of more than 150/90 mmHg at least once during the 24-hour period. The incidence of ABPs greater than 150/90 mmHg among all readings was higher in untreated and treated hypertensives with diastolic BPs in the office of more than 105 mmHg, and, when checked along with the clock time, higher not only in the morning but also in the evening. On the other hand, one-third or one-fifth of treated hypertensives with diastolic office BPs less than 90 mmHg or between 90 and 105 mmHg respectively had ABPs less than 150/90 mmHg throughout the whole day. When the effect of nicardipine (60 mg, t.i.d.) or slow-release nifedipine (27.3 +/- 3.0 mg, b.i.d.) on minimum BP during the night was analyzed, long-acting nifedipine decreased BP throughout the night to levels not significantly different from normotensive controls, whereas short-acting nicardipine did not affect nighttime BPs. These results suggest that simple ABP monitoring throughout the day gives us useful information to evaluate the severity of hypertension and the efficacy of antihypertensive medication as well as to avoid overtreatment with long-acting hypotensive agents resulting in a great fall in BP during sleep.
4 citations
TL;DR: It is suggested that the decrease of laminin B2 mRNA during hyperglycemia or exposure to high osmolarity may have some pathophysiologic significance in the development of diabetic nephropathy.
3 citations
TL;DR: It is suggested that FBF may be a simple and useful index for determining arterial and/or venous distensibility, and that alpha 1-blocker therapy, in addition to glycemic control, mayBe a first-line antihypertensive treatment for diabetics with associated hypertension.
3 citations
TL;DR: The results suggest that renal PGE2 synthesis is stimulated or decreased by 1-week Ca loading or deprivation, indicating a possible antihypertensive role of renal P GE2 during high-Ca intake in hypertensives.
Abstract: The present study was designed to clarify the possible role of renal prostaglandins (PGs) on blood pressure (BP) regulation during calcium (Ca) restriction or supplementation. Twelve normotensive women with a mean age of 21.2 years participated in the study. After 1 week of normal Ca intake (mean +/- SE, 536 +/- 2 mg/day), a low-Ca diet (163 +/- 1 mg/day) was given for a further 1 week. Additional asparagine Ca (3 g as Ca/day) was also given to half of the subjects. BP, heart rate, and serum total and ionized Ca concentrations were measured at the end of each period. Levels of Ca, sodium, PGE2, 6-keto-PGF1 alpha and thromboxane (TX) B2 excreted into urine were also determined. The plasma level of ionized Ca was significantly increased without any change in total Ca in both groups. Low and high Ca intake decreased and increased urinary Ca excretion by 28% and 56%, respectively. BP was not altered after Ca deprivation or loading. However, urinary PGE2 excretion was significantly augmented from 668.9 +/- 68.1 to 959.7 +/- 183.1 ng/day by Ca loading, whereas Ca deprivation decreased PGE2 excretion (695.4 +/- 108.1 to 513.2 +/- 55.2 ng/day). No changes were observed in 6-keto-PGF1 alpha or TXB2 urinary excretion. These results suggest that renal PGE2 synthesis is stimulated or decreased by 1-week Ca loading or deprivation, indicating a possible antihypertensive role of renal PGE2 during high-Ca intake in hypertensives.
3 citations
TL;DR: The role of arginine vasopressin (AVP) in blood pressure regulation in humans and animals is still controversial as discussed by the authors, however, the role of AVP in the regulation of blood pressure and the excretion of prostaglandin (PG) E2 in animals is well established.
Abstract: The role of arginine vasopressin (AVP) in blood pressure regulation in humans and animals is still controversial. The present study was designed to investigate the effects of AVP on blood pressure and the excretion of sodium and prostaglandin (PG) E2 in rabbits. AVP dissolved in 0.01 M acetic acid was infused subcutaneously at a rate of 0.86 ng/kg/min with a miniosmotic pump into 12 New Zealand white rabbits (2.7±3.4 kg), while 10 controls were given vehicle alone. AVP infusion resulted in a 3.5-fold rise in the level of plasma AVP (21.8±4.4 (SEM) pg/ml) as compared with controls, associated with a signifcant decrease in the urine volume and urinary excretion of sodium. The PGE2 excretion was increased 1.8-fold after AVP infusion. In the chronic AVP-infused group, blood pressure was not significantly increased, but the acute vascular response to AVP was significantly attenuated without any changes in the vasopressor response to angiotensin II. Preadministration of V1-antagonist completely abolished the vasopressor action of AVP, but not that of angiotensin II, in either group. These results suggest that circulating AVP within physiological range of concentrations may stimulate renal PGE2 synthesis and attenuate the vascular response through vascular V1 receptors without affecting the baroreflex, which may be attenuated through V2 receptors.
2 citations
TL;DR: The results suggest that the possibility that long-acting hypotensive agents may cause a great fall in nighttime BP during sleep, especially in the elderly, must be taken into consideration.
Abstract: With the advent of long-acting or slow-release antihypertensive drugs, we should be aware of a fall in nighttime blood pressure (BP) as well as daytime blood pressure. In the present study, casual BPs at the physician's office as well as ambulatory BP was recorded every hour throughout 24 hours with a noninvasive automated BP monitoring device in 24 essential hypertensives treated with slow-release nifedipine. Administration of slow-release nifedipine (20-40mg, b.i.d.) decreased not only casual BPs but also ambulatory mean BP during the whole day or daytime (6 am to 10 pm). Slow-release nifedipine at 10mg in the morning did not affect casual BPs at the office. However, mean BP obtained by ambulatory BP monitoring during the daytime was significantly attenuated.In addition, a profound fall in mean BP amounting to more than 20mmHg during the night in some of the patients was observed during treatment with slow-release nifedipine not only at 20-40mg (b.i.d.) but also at 10mg once a day.These results suggest that we have to take into consideration the possibility that long-acting hypotensive agents may cause a great fall in nighttime BP during sleep, especially in the elderly.