AH Groups Research Articles

The pathogenesis of hypercalciuria from the aspect of the response to human parathyroid hormone in Ca containing stone formers

In order to clarify the pathogenesis of hypercalciuria, the response to extrinsic human parathyroid hormone (h-PTH) was studied the 21 patients with calcium containing urinary stone(s) and 5 normal controls (NO). The stone patients were classified into 3 groups from the result of the oral calcium loading test, i.e. Non-hypercalciura (NH, n = 8) and absorptive hypercalciuria (AH, n = 8) and renal hypercalciuria (RH, n = 5). Only in the AH group, urinary excretion of calcium (u-Ca) was strongly correlated to that of sodium (u-Na) in pre-load of h-PTH, and both increments were also correlated in post-load of h-PTH. As of this fact the increase in Na excretion seems to be responsible for a cause of hypercalciuria in the AH group. There was a significant correlation between the value of %TRP in pre-load of h-PTH and the rate of urinary phosphorus (P) increment between pre-load and post-load of h-PTH in the NO and NH groups. However, this relationship was not found in the AH and RH groups. These findings indicate that there is response disorder of P to h-PTH. In addition, serum P was low, plasma 1,25 (OH)2D was high, N-c-AMP was low in the AH group, whereas both serum P and %TRP were low in the RH group in pre-load of h-PTH. These findings are compatible with the primary renal P leak.(ABSTRACT TRUNCATED AT 250 WORDS)

On the mechanism of the broadening of the proton vibrational IR band in weak hydrogen bonds. Double adiabatic approximation

Abstract It is proposed that broadening of the νs (AH) IR band is due to the νs (AH) and νσ (AH…B) mode coupling and to the stochastic variation of the equilibrium distance Re (A…B) modulating the proton vibration. The Re disordering variation is caused by a coupling of the νσ mode with the low frequency oscillators (νQ) of the medium and of the complex as such. Besides, the (νσ, νQ) and (νs, νσ) couplings cause a νs frequency shift. Both the band broadening and the frequency shift increase with higher force constants responsible for (νσ, νQ) mode coupling. Furthermore the Qi low frequency stochastic vibrations directly modulate the νσ (AH…B) vibration and the free AH groups stretching vibration (νos) causing some broadening at their bands which is however several times smaller than the νs band broadening in the complex. Several examples are reported to confirm the proposed model.

Effect of selective hippocampal lesions in the rat on acquisition, performance, and extinction of bar pressing on a fixed ratio schedule.

Rats with bilateral anterior and posterior hippocampal lesions (APH), anterior hippocampal lesions (AH), and controls were trained on CRF for water, and then switched to FR-20. Both hippocampal groups adapted more readily than controls to the FR-20 schedule and maintained significantly higher rates for 45 days. There were no significant differences on FR-20 between the lesion groups. Following FR-20, the rates of all groups were equalized by training on FR-30. During subsequent extinction, the APH group made significantly more responses than both the AH and control groups, while AH and control groups were indistinguishable. The acquisition results were interpreted as indicating increased emotional reactivity to delay of anticipated reward in both hippocampally lesioned groups. The extinction results suggested that APH, but not AH, lesions also result in increased perseveration.