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Biomedical subjects

H Mulder

Publications and source records attributed to H Mulder.

At least 91 records · Page 5Linked to original sources

Calcitonin-testosterone interrelationship. A classic feedback system?

Calcitonin infusion in pharmacological doses reduces the serum concentration of testosterone, LH and FSH, probably by acting at the hypothalamic level. This fact, in combination with the well-known calcitonin stimulating effect of testosterone, suggests that calcitonin and testosterone are possibly acting as a classic negative feedback system.

Adult↗

Normocalcemia with persistent increase of parathyroid hormone: a prospective study.

Twelve patients were followed up for 3 months after parathyroidectomy. Serial measurements of serum parathyroid hormone (PTH), calcium, and phosphate were made. Four patients had an increased serum PTH postoperatively, which was already apparent by the third postoperative day. All patients became normocalcemic. Their hyperparathyroid-like phosphate parameters indicated that we were dealing with a biologically active PTH. Using preoperative biochemical parameters it was impossible to predict which patients would have an increased PTH postparathyroidectomy (PTX). Probably the patients with high PTH post-PTX had higher parathyroid volumes. In our opinion after PTX, a normocalcemic high PTH situation should be avoided by 3 1/2 parathyroid gland extirpation in all cases.

Aged↗

Pectus excavatum. A clinical study with long-term postoperative follow-up.

Between 1972 and 1987, 192 patients have been operated upon for pectus excavatum of which 152 patients were included in the study (79%). Mean age at operation was 15.3 +/- 5.5 years; 117 were male. Mean follow-up was 8.1 +/- 3.6 years. The deformity was noted before the age of 5 in 90%. Type I symmetrical and localized deformity was seen in 33.2%, type II symmetrical but diffuse depression in 23.7% and type III localized or diffuse asymmetrical deformity in 43.1%. It was considered severe in 68.9%, fair in 16.9% and mild in 14.2%. There were significantly more asymmetrical defects in the older age groups. The operation consisted of subperichondral chondrectomy, transverse sternotomy and division of the intercostal bundles at the outer limit of the chondrectomy and suturing the edge of this broad sheet of muscle and perichondrium to the anterior surface of the chest wall more laterally and under tension, elevating and stabilizing the sternum. Results were satisfactory in 83.6% (excellent 44.1%, good 39.5%). Results were not significantly influenced by age, sex, severity, type, symmetry, the extent of cartilage resection or follow-up. Results were inversely influenced by the occurrence of wound problems. The optimal age for operation is considered to be between 5 and 10 years. Both physical as well as psychological cosmetic factors may serve as an indication for operation.

Adolescent↗

Assignment of the aspartylglucosaminidase gene (AGA) to 4q33----q35 based on decreased activity in a girl with a 46,XX,del(4)(q33) karyotype.

Aspartylglucosaminuria (AGU) is a recessive autosomally inherited lysosomal storage disorder due to deficiency of the enzyme aspartylglucosaminidase (AGA). The structural gene for this human enzyme (AGA) has been assigned to the region 4q21----qter. We determined the AGA activity in cultured fibroblasts of a girl with a 46,XX,del(4)(q33) karyotype. The results indicate that the girl is a hemizygote for AGA, permitting the assignment of human AGA to the region 4q33----qter.

Aspartylglucosaminuria↗

Identification of a novel UDP-Gal:GalNAc beta 1-4GlcNAc-R beta 1-3-galactosyltransferase in the connective tissue of the snail Lymnaea stagnalis.

Connective tissue of the freshwater pulmonate Lymnaea stagnalis was shown to contain galactosyltransferase activity capable of transferring Gal from UDP-Gal in beta 1-3 linkage to terminal GalNAc of GalNAc beta 1-4GlcNAc-R [R = beta 1-2Man alpha 1-O(CH2)8COOMe, beta 1-OMe, or alpha,beta 1-OH]. Using GalNAc beta 1-4GlcNAc beta 1-2Man alpha-1-O(CH2)8COOMe as substrate, the enzyme showed an absolute requirement for Mn2+ with an optimum Mn2+ concentration between 12.5 mM and 25 mM. The divalent cations Mg2+, Ca2+, Ba2+ and Cd2+ at 12.5 mM could not substitute for Mn2+. The galactosyltransferase activity was independent of the concentration of Triton X-100, and no activation effect was found. The enzyme was active with GalNAc beta 1-4GlcNAc beta 1-2Man alpha 1-O(CH2)8COOMe (Vmax 140 nmol.h-1.mg protein-1; Km 1.02 mM), GalNAc beta 1-4GlcNAc (Vmax 105 nmol.h-1.mg protein-1; Km 0.99 mM), and GalNAc beta 1-4GlcNAc beta 1-OMe (Vmax 108 nmol.h-1.mg protein-1; Km 1.33 mM). The products formed from GalNAc beta 1-4GlcNAc beta 1-2Man alpha 1-O(CH2)8COOMe and GalNAc beta 1-4GlcNAc beta 1-OMe were purified by high performance liquid chromatography, and identified by 500-MHz 1H-NMR spectroscopy to be Gal beta 1-3GalNAc beta 1-4GlcNAc 1-OMe, respectively. The enzyme was inactive towards GlcNAc, GalNac beta 1-3 GalNAc alpha 1-OC6H5, GalNAc alpha 1--ovine-submaxillary-mucin, lactose and N-acetyllactosamine. This novel UDP-Gal:GalNAc beta 1-4GlcNAc-R beta 1-3-galactosyltransferase is believed to be involved in the biosynthesis of the hemocyanin glycans of L. stagnalis.

Animals↗

Extrapancreatic insulin effect of glibenclamide.

In eight patients with uncomplicated non insulin dependent diabetes mellitus, serum insulin levels, serum C-peptide levels and blood glucose levels were measured before and after oral administration of glibenclamide 0.1 mg/kg body weight and a test meal, or after a test meal alone. The rise in serum insulin levels persisted longer after glibenclamide. The initial rise in serum insulin was of the same magnitude in both situations, as was the rise in serum C-peptide levels during the entire 5 h study. It is concluded that glibenclamide is able to maintain a more prolonged increase in serum insulin levels by inhibiting the degradation of insulin in the vascular endothelial cells of the liver. The inhibition contributes to the blood glucose lowering effect of glibenclamide.

Administration, Oral↗

Change of serum calcitonin in patients receiving glucocorticoids: an acute phase study.

The basal and calcium-stimulated calcitonin response was measured in 10 patients with giant cell arteritis before and 1, 3 and 6 wk after the start of daily treatment with 60 mg of prednisone. The study shows that plasma calcitonin level in response to a calcium injection is increased after 1 wk treatment with prednisone. Later on the calcitonin secretion capacity diminishes significantly compared to the initial level. The phylogenetic old calcitonin system first tries to prevent the occurrence of the process of osteoporosis. Moreover, exhaustion of this system later contributes to the process of steroid osteoporosis.

Acute Disease↗

[The lateral capsule sign in the traumatized knee joint].

The lateral capsular sign is a simple radiographic finding visible on routine anteroposterior knee x-ray near the tibial articular surface at the lateral point of the lateral tibial plateau. The lateral capsular sign is a flake of bone superior and posterior to the insertion of the iliotibial tract, and represents an avulsion of the meniscotibial portion of the lateral capsular ligament. A positive lateral capsular sign implies disruption of the lateral capsule and a tear of the anterior cruciate ligament. These findings are illustrated by clinical examples.

Humans↗

Influence of pharmacological doses of calcitonin on serum osteocalcin concentration in patients with Paget's disease of the bone.

The effect of continuous infusion of calcitonin on serum osteocalcin concentration was studied in 14 patients with Paget's disease. In all patients serum osteocalcin was initially increased. Within 24 h calcitonin gradually reduced serum osteocalcin, a marker of osteoblastic activity. This means that inhibition of the function of the osteoclasts by calcitonin results in an inhibition of the osteoblasts within 24 h in patients with Paget's disease.

Aged↗

Does thyroid function influence serum beta 2-microglobulin?

In 24 patients with hyperthyroidism (15 with Graves' disease and 9 with toxic nodular goitre), serum beta 2-microglobulin (beta 2-m) levels were measured prior to and during 6 wk of treatment with carbimazole. The same schedule was followed in 7 patients with hypothyroidism, but their treatment consisted of levothyroxin in increasing doses. In 16 of the patients with hyperthyroidism, beta 2-m was initially found to be increased. In all these patients an increased beta 2-m declined to normal or near-normal levels. The patients with hypothyroidism had a normal medium serum beta 2-m. During substitution there was a tendency for the serum beta 2-m to decline. Indirect arguments are stated for the hypothesis that both in Graves' disease and in toxic nodular goitre activated T-lymphocytes are modulated in their function by carbimazole acting as an immunosuppressing agent. Moreover, we conclude that thyroid hormone levels are not directly responsible for the increased serum beta 2-m concentrations in hyperthyroidism.

Adult↗

Decrease of serum testosterone by cyproterone acetate accompanied by an unexpected increase of calcitonin secretion capacity.

The interaction between testosterone and calcitonin secretion capacity was studied in 9 patients with prostatic cancer. Treatment with the antiandrogenic agent cyproterone acetate resulted in an expected decrease in serum testosterone but an unexpected and unexplained increase in calcitonin secretion capacity. The previous statement that a positive correlation between sex hormones and calcitonin secretion capacity can be recognized probably requires revision. This unexpected effect of cyproterone acetate had possible additive beneficial advantages for treatment, such as bone mass sparing and its analgesic effect.

Aged↗

Acute changes in plasma renin activity, plasma aldosterone concentration and plasma electrolyte concentrations following furosemide administration in patients with congestive heart failure--interrelationships and diuretic response.

We studied the effects of furosemide on plasma renin and plasma aldosterone in 8 patients with mild to moderate congestive heart failure. In particular, we tried to correlate these effects with changes in plasma electrolyte concentrations and with the diuretic response on furosemide. We concluded that the diuretic response in patients with congestive heart failure is not dependent on the initial serum renin nor on the initial serum aldosterone concentration. The diuretic response did not correlate either with the changes in serum renin and/or serum aldosterone concentration. Serum renin and serum aldosterone correlated mutually before and after intravenous furosemide. We confirmed the inverse correlation between serum sodium and serum renin. SeNa and SeK correlated at all times with serum aldosterone; SeCl correlated with serum aldosterone only before intravenous furosemide administration. Indirect evidence could be provided that in patients with congestive heart failure a decreased renal blood flow is present, using the urinary beta 2-microglobulin concentration. Aldosterone has again, indirectly, proved to be integrated in the renal magnesium handling.

Aged↗

Stimulation of calcitonin secretory capacity by increased serum levels of testosterone in men treated with tamoxifen.

Previous studies have suggested that sex steroids, including both oestrogen and testosterone, influence calcitonin secretion. However, a negative effect of gonadotrophins on calcitonin has not been excluded. Twelve men with infertility and low-normal serum levels of testosterone were studied before and during tamoxifen therapy. Increases in the serum levels of LH, FSH, testosterone and calcitonin were observed after treatment. Our findings suggest that testosterone has a direct influence on calcitonin secretion.

Calcitonin↗