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Biomedical subjects

M Mostert

Publications and source records attributed to M Mostert.

At least 19 recordsLinked to original sources

The insulin signal and its effects on the pyruvate dehydrogenase complex in circulating lymphocytes of obese children.

1. Studies have shown that in circulating lymphocytes pyruvate dehydrogenase (PDH) is responsive to insulin. 2. To improve existing knowledge on how insulin influences PDH behaviour, situations in which cell responsiveness to insulin is impaired could be of interest. 3. PDH behaviour in circulating lymphocytes from obese children, with high plasma insulin levels and normal glucose tolerance, was examined. 4. Masking and unmasking processes of insulin receptors on the plasma membrane appear to modulate the enzyme response to insulin.

Adolescent

Modified Greulich-Pyle, Tanner-Whitehouse, and Roche-Wainer-Thissen (knee) methods for skeletal age assessment in a group of Italian children and adolescents.

Modified Greulich-Pyle (GP), Tanner et al. 2, radius, ulna and short bones (TW2-RUS), TW2-20-bone and Roche-Wainer-Thissen RWT (knee) skeletal age assessments were made in an Italian population sample of 128 males and 93 females aged 4.1-16.9 years. All the scales appear to be well-suited to the Italian population despite minor differences. A very high correlation was found between the assessment of knee skeletal ages by the RWT method and that of the hand-wrist by the GP and TW2 systems in the same subject without sex and age-associated variations.

Adolescent

Pyruvate dehydrogenase activation by insulin in human circulating lymphocytes and the possible pathway involved.

1. The incubation of human fresh circulating lymphocytes with insulin leads to modifications in the behaviour of the pyruvate dehydrogenase complex (PDH) when the contact medium is supplemented with 50 microM Ca2+ and Mg2+. 2. To investigate the mechanism involved in the PDH responsiveness to insulin in circulating lymphocytes and the role of Ca2+ and Mg2+ in this process, the PDH activity was assayed in lymphocytes combined with insulin and/or a number of substances whose mechanism of action is partially known. 3. Of these some have been seen to mimick insulin effects on PDH, whereas other were tested for the first time in this study.

Enzyme Activation

Beta-endorphin-like and alpha-MSH-like immunoreactivities in human milk.

We measured with radioimmunoassay the beta-endorphin-like and alpha-MSH-like immunoreactivities in milk and plasma of 8 lactating women. Mean beta-endorphin concentrations ( +/- SD) were 16.6 +/- 6.7 fmol/ml in milk and 9.9 +/- 4.1 fmol/ml in plasma. alpha-MSH concentrations (mean +/- SD) were 39.4 +/- 15.5 pg/ml in milk and 18.2 +/- 8.4 pg/ml in plasma. The concentrations of both peptides in milk were significantly (p less than 0.05) higher than in plasma. No significant correlation between milk and plasma concentrations of these peptides was found.

Adult

The behaviour of pyruvate dehydrogenase in circulating lymphocytes from diabetic children.

The basal and total pyruvate dehydrogenase activities were assayed in circulating lymphocytes from children with juvenile diabetes at diagnosis and after five days of insulin therapy and from control subjects. In untreated diabetic children, basal and total pyruvate dehydrogenase activities were deeply decreased and both showed very similar values; whereas, in control subjects basal activity was about 30% lower than total activity. In diabetic patients treated with insulin (in vivo situation), both basal and total activity levels were equal or even higher than those of the control subjects. The incubation of lymphocytes from diabetic patients with insulin (5 microU/ml) (in vitro situation) stimulates, but less than in vivo, the basal and total pyruvate dehydrogenase activities.

Blood Glucose

[Serum prealbumin standards in the neonatal period].

Serum prealbumin standards for the first and sixth days of life have been determined by immunoprecipitation ascertained with kinetic nephelometry in two samples of healthy newborns, born at term and of normal weight.

Birth Weight

Growth and development in simple obesity.

It is well known that fat children tend to be taller than their peers and to present a slight acceleration of skeletal and pubertal maturation. To verify this tendency and to examine some of the points that are still controversial, auxological data were studied concerning 303 subjects (141 males and 162 females, aged 6-16 years) affected by simple obesity. Subjects were seen to be taller than average by about 1 SD from 6 to 9 years of age, becoming close to or shorter than average at later ages. Height below the 10th percentile was common in 17% of males and 8% of females, due to hereditary shortness, growth delay or late puberty. Girls had early puberty and menarche; the rate of sexual maturation was variable in boys.

Adolescent

Intraoperative use of laser Doppler in the study of cerebral microvascular circulation.

Laser Doppler (LD) flowmetry has been used for evaluation of microcirculatory flow in a variety of human tissues, including skin, muscle, retina and recently the brain. In the present paper, intraoperative Laser Doppler recordings have been performed in 72 cases, in basal conditions and after stimulation. The morphology of basal recordings obtained from normal cortical areas were analyzed and three different rhythmical variations were identified; these rhythmical variations are described and explained. Several kinds of stimulation have been used: hypotensive drugs, mannitol, nimodipine, eupaverine, hypercapnia, decompressive manoeuvres and temporary occlusion of the ICA in the neck. Laser Doppler recordings obtained during and after these stimulations are reported and explained. The results have been evaluated in order to verify the reliability and the reproducibility of this technique in the study of the cerebral microvascular circulation intraoperatively.

Adult

Effects of insulin on pyruvate dehydrogenase in circulating lymphocytes from normal and diabetic rats.

1. The in vivo and in vitro conditions which allow a response of rat circulating lymphocyte PDH to insulin are investigated. 2. In vivo tests show that inactive PDH (PDHi) prevails in diabetic rats and active PDH (PDHa) in hyperinsulinemic rats; in treated with insulin diabetic rats the PDHa/PDHi ratio (1.7) is similar to that of normal rats (PDHa/PDHi ratio = 2). 3. In vitro tests show a responsiveness of PDH to insulin only when 50 microM Ca2+ -Mg2+ and intact lymphocytes are used in the incubation medium. Insulin concentrations and contact time are important variables.

Animals

Insulin modulation of pyruvate dehydrogenase in human circulating lymphocytes.

1. In human circulating lymphocytes pyruvate dehydrogenase (PDH) complex is present in the active (PDHa) and inactive (PDHi) forms. 2. PDHi conversion into PDHa is stimulated when intact lymphocytes are incubated with 5 microU/ml insulin at pH 7.4, for 15 min at 37 degrees C in a medium supplemented with 50 microM Ca2+-Mg2+. 3. The generation of a mediator is strongly suggestive since a cell free preparation from circulating lymphocytes, treated as above described, still stimulates PDHi----PDHa conversion, when combined with either disrupted or intact lymphocytes.

Calcium

Transient hyperphosphatasemia of infancy. Fifteen new cases.

Alkaline phosphatase was assayed as part of the routine examinations performed in all children hospitalized for the first time in our ward. Fifteen children had transient hyperphosphatasemia of infancy (THI). Their clinical features suggested the presence of an infectious agent.

Alkaline Phosphatase