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Biomedical subjects

A Winter

Publications and source records attributed to A Winter.

At least 109 records · Page 6Linked to original sources
PubMed1966

Bound indoleacetic Acid in Avena coleoptiles.

When C(14) carboxyl indoleacetic acid (IAA) is transported through Avena coleoptile sections a fraction of the activity becomes bound. The nature of this bound IAA has been investigated. Upon extraction with solvents and chromatography a substance having the R(F) of IAA in 4 solvents was detected. No evidence could be found for the formation of indoleacetyl conjugates. In pea stem sections subjected to a similar experimental regime good evidence was obtained for the occurrence of conjugates. When IAA was supplied exogenously to coleoptile sections floating in solutions the occurrence of conjugates was shown to be dependent on the presence of the primary leaf. In its absence no conjugates could be detected.On grinding coleoptile sections and subsequent centrifugation at 240 x g the radioactivity was found to be in the tissue fraction as opposed to the supernatant. The radioactivity cannot be removed from the tissue by extraction with water, buffer solution or treatment with ribonuclease. It is readily removed by 10% urea, crystalline trypsin and chymotrypsin. It is therefore concluded that IAA becomes bound to a protein. Bound IAA does not appear to be able to cause growth in Avena coleoptile sections.

Journal Article↗
PubMedDate not supplied

Biopsy of the bovine mammary gland.

A technique is described for biopsy of the bovine udder, employing sedation and local anaesthesia. Tissue samples of approximately 5 g were obtained by electrocautery from two quarters of the udder of a cow laterally recumbent. Care was taken to ensure complete haemostasis which was achieved by electrocoagulation and ligation. Postoperative recovery was rapid, and loss of yield was no greater in biopsied glands than in control glands of the same cow. Yield from all quarters returned to preoperative levels within 48 h.

Anesthesia, Local↗
PubMedDate not supplied

Treatment and disease effects on short-term growth and adult height in children and adolescents with 21-hydroxylase deficiency.

BACKGROUND: In clinical practice, height velocity and rate of bone maturation during each follow-up interval are among the parameters used to modify glucocorticoid treatment in children with 21-hydroxylase deficiency. There is controversy on the relative importance of treatment and disease variables for short-term growth and final height. PATIENTS AND METHODS: Short- and long-term growth data of 87 patients (n = 35 salt-wasting form; n = 52 simple virilizing form) were analysed retrospectively by stepwise multiple regression. RESULTS: Height SDS for chronological age (HtSDSCA) was elevated prior to treatment in boys (m = 3.22, p < 0.0001) and decreased when compared to HtSDSCA > or = 4 years after the start of treatment in both boys (m = -0.64, p < 0.0001) and girls (m = -1.24, p < 0.0023). When the simultaneous effects of hydrocortisone dose, salt-wasting status, degree of hormonal control, and patient sex on short-term growth between follow-up visits were analysed, only a minor effect of hydrocortisone dose (partial coefficient of determination [Pr2] = 0.04, p < 0.011) and salt-wasting status (Pr2 = 0.03, p < 0.024) in the prepubertal group, and a small effect of the treatment quality rating in the pubertal group (Pr2 = 0.07, p < 0.0042) on height velocity SDS for chronological age (HVSDSCA) were noted. Height velocity SDS for bone age (HVSDSBA) was influenced to a similar degree by treatment quality (Pr2 = 0.098, p < 0.0017) in the prepubertal, and by hydrocortisone dose (Pr2 = 0.063, p < 0.021) in the pubertal group. Mean daily hydrocortisone doses used in normally growing patients ranged between 17.9 and 21.8 mg/m2/d if analysed separately for sex and salt-wasting status. 34 patients had reached final height which with the exception of one boy was below the population mean and ranged from 82.3% to 100.1% of target height in the total group. 41.2% of the patients had adult short stature (HtSDS < -2). Treatment with synthetic glucocorticoids for more than 1 year started before the age of 1.5 years was associated with the most severely compromised final height SDS (m = -3.73, p < 0.029). CONCLUSIONS: The proportion of the short-term height velocity SDS that can be explained by the tested treatment and disease variables is low (< or = 9.8%). Conclusions drawn from observed changes in height velocity during single short follow-up intervals on treatment modalities must therefore be viewed with caution. In the long run, however, use of daily hydrocortisone doses > 25 mg/m2/day and of synthetic glucocorticoids started early in the course of the disease does not only lead to a transient deceleration of height velocity in growing children with 21-hydroxylase deficiency, but carries a definite risk for decreased final height.

Adolescent↗