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Biomedical subjects

H Horikawa

Publications and source records attributed to H Horikawa.

At least 73 records · Page 4Linked to original sources
PubMed1982

Disorders of cholecalciferol metabolism in old egg-laying hens.

It has been reported that the rate of cracked or soft-shelled eggs markedly increases in old laying hens. We investigated the effect of age on cholecalciferol metabolism in different age groups of laying hens. The egg production rate in hens more than 500 days old was maintained within a range of about 70% of that in young hens (230-320 days old), whereas the rate of cracked or soft-shelled eggs increased markedly with age. When kidney homogenates from the different age groups were incubated with [3H]-25-hydroxyvitamin D-3, renal 25-hydroxyvitamin D-3-1 alpha-hydroxylase activity was found to decrease markedly with age. When birds were given intravenously either [3H]-25-hydroxyvitamin D-3 or [3H]-1 alpha,25-dihydroxyvitamin D-3, the accumulation of [3H]-1 alpha,25-dihydroxyvitamin D-3 in plasma and target tissue also decreased with age. Forced molting performed in old hens restored eggshell quality. The treatment also restored, though partially, the in vivo accumulation of [3H]-l alpha,25-dihydroxyvitamin D-3 in the target tissues. These results suggest that the increased rate of cracked or soft-shelled eggs seen in older birds is associated with disorders of vitamin D-3 metabolism.

25-Hydroxyvitamin D3 1-alpha-Hydroxylase↗
PubMed1979

Computer analyses of Rohrer's coefficients.

In the field of respiratory physiology computers have been used for theoretical and automatic analyses of the test results. The purpose of this paper is to clarify whether computers are available in measurement of the nasal resistance. The nasal cavities, simulated by an acryl resin model, were ventilated at various volumes and speeds. The pressure and flow changes were recorded by a data recorder and analyzed by a minicomputer according to the prescribed situations. Rohrer's formula P = K1V+K2V2 and its modification R = K1+K2V were used for calculation of K1 and K2. The calculated values differed significantly when sampling was made on a particular part of the respiratory excursion or sampling time was extraordinarily prolonged. They were also different from the ordinary values when too slow or too rapid ventilatory speed was applied. It was concluded that more than twenty samplings were necessary at regular intervals in a normal inspiratory or expiratory phase. Too slow and too rapid respiration should be avoided because of functional limitations of the measuring apparatus.

Airway Resistance↗
PubMed1978

Enzyme-linked immunoassay of somatostatin.

An enzyme-linked immunoassay for somatostatin using somatostatin-alkaline phosphatase conjugate as "labeled" antigen was developed. Minimal detectable dose at present was 40 pg per tube. Serial dilutions of rat hypothalamic extract gave a gradual change of antibody-bound alkaline phosphatase activity which was parallel to that with standard somatostatin. Precision and accuracy of the method were comparable to those in radioimmunoassay reported by others. This method will be a useful tool for the determination of somatostatin, especially in tissues.

Alkaline Phosphatase↗