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Biomedical subjects

I Kjaer

Publications and source records attributed to I Kjaer.

At least 109 records · Page 6Linked to original sources
PubMed1978

Histochemical and radiologic studies of the human fetal mandibular condyle.

Histochemical investigations on the mandibular condyle were performed on 72 human embryos and fetuses of crown-rump lengths (CRL) ranging from 26 to 186 mm, representing skeletal maturity indices expressed in CNO values (CNO = composite number of ossified bones in the hand and foot) ranging from 0-0 to 19-12. The development of the mandibular condyle is described according to morphology and to histochemical reactions for glycosaminoglucuronglycans, collagen, glycogen, alkaline and acid phosphatase, and nonspecific AS esterase. The development is described for (1) the bony component of the mandibular condyle, (2) the condylar cartilage, and (3) the fibrous cover of the mandibular condyle. For each tissue component, maturation steps are set up and included in the total evaluation of the condylar maturity stages. The developmental sequence set up on the basis of the morphologic and histochemical findings was followed by all condyles investigated. From this it may be presumed that the developmental sequence in human mandibular condylar components is constant during the former half of the prenatal period. The material available did not justify a description of skeletal development in the mandibular condyle as a function of fetal size, CRL, or skeletal maturity in the hand and foot.

Alkaline Phosphatase↗
PubMed1977

Effect of 1alpha-hydroxycholecalciferol in senile osteoporosis and in bone loss following prednisone treatment.

Synthetic 1alpha-hydroxycholecalciferol, a potent vitamin D analogue, was given daily together with calcium to seven patients with senile osteoporosis and to three patients with prednisone-induced bone loss. Quantitative bone histology indicated increased formation and mineralization after three months of treatment. The bone resorption was reduced, a finding supported by a decrease in the urinary hydroxyproline excretion. Photon absorptiometry of the forearm showed a significant rise in the bone mineral content, in accordance with the histological findings. Serum calcium rose in all patients and severe hypercalcemia developed in one case. Urinary excretion of calcium and magnesium increased significantly. The findings indicate that treatment with 1alpha-hydroxycholecalciferol may be useful in osteoporosis due to aging or following corticosteroid administration. The patients must be carefully followed up because of the risk of hypercalcemia.

Aged↗
PubMed1975

Treatment of osteoporosis of ageing with 1alpha-hydroxycholecalciferol.

Seven patients with osteoporosis of ageing were treated with synthetic 1alpha-hydroxycholecalciferol (1alpha-H.C.C.) for 3-4 months. The compound was given at a daily oral dose of 2 mug together with an oral supplement of 1 g of calcium. Clinically there was a striking improvement in the patients' physical fitness. Increased bone formation and mineralisation were seen on iliac-crest bone biopsy, and this was supported by an increased osteoblastic activity demonstrated by histochemical measurement of alkaline-phosphatase activity. Bone histology furthermore showed a reduced bone resorption, which was supported by a reduced urinary excretion of total hydroxyproline. Photon absorptiometry of the forearm accorded with the histological findings, showing a significant increase in the bone mineral content. Serum-calcium rose in all patients, one developing a severe transitory hypercalcaemia. The urinary excretion of calcium and magnesium increased significantly. The serum concentrations of 25-hydroxycholecalciferol and parathyroid hormone were not significantly affected by the treatment. It is concluded that 1alpha-H.C.C. is an effective tool in the treatment of senile osteoporosis.

Administration, Oral↗
PubMed1975

Mitochondrial granules in human osteoblasts with a reference to one case of osteogenesis imperfecta.

Electron-dense granules in mitochondria from prenatal human osteoblasts, postnatal human osteoblasts, and from osteoblasts derived from a child with osteogenesis imperfecta congenita are described. The mitochondrial granules were of about 600 A in diameter and were attached to the mitochondrial cristae. Sections of mitochondria from prenatal osteoblasts showed an average number of 10 granuales per mitochondrial section, whereas sections of mitochondria of postnatal osteoblasts showed only occasionally 1-2 granules per mitochondrial section. Mitochondria from osteoblasts derived from the child with an untreated osteogenesis imperfecta congenita showed an average number of 10 granules per mitochondrial section.

Adolescent↗
PubMed1975

Histochemical investigations on the symphysis menti in the human fetus related to fetal skeletal maturation in the hand and foot.

Histochemical investigations on the symphysis menti region were performed on 72 human embryos and fetuses of crown-rump lengths (CRL) ranging from 16 to 162 mm, presenting skeletal maturity indices (CNO = composite number of ossified bones in the hand and foot) ranging from 0-0 to 19-11. The symphysis menti region is described in five developmental stages according to morphology and histochemical reactions at the interzone, enchondral bone formation, and Meckel's cartilage. The stages are described according to histochemical reactions for glycosaminoglucuronoglycans, collagen, glycogen, alkaline and acid phosphatase, and non-specific AS esterase. Silver impregnation followed by X-ray and histochemical control for Ca++ deposits supplemented the study. Special attention was paid to a fusion of the bilateral Meckel's cartilages in the midline characteristic of stage II. This is a finding not previously recorded in human fetuses. It is suggested to designate this fusion 'the rostral connection'. Histochemically, the fusion appeared as ordinary cartilage matrix (chondroitin-4- and/or-6-sulphate). The absence of a rostral connection characteristic of stage III is discussed. On the basis of reactions for glycosaminoglycans and activity of hydrolytic enzymes, the symphysis is characterized as a growth zone, active in mandibular growth in width as well as in length, during the first half of the prenatal period. The material available did not justify a description of skeletal development in the symphysis menti as a function of CRL, of skeletal maturation in the hand and foot, or as a function of a combination of these parameters.

Acid Phosphatase↗
PubMedDate not supplied

Cervical ribs: useful marker of monosomy X in fetal hydrops.

Cervical ribs were observed in six hydropic fetuses with 45X karyotype. To test the usefulness of this observation in the macerated hydropic fetus where chromosome culture is problematic, a group of 36 hydropic fetuses was examined. Cases were chosen to include fetuses with several karyotypic and pathological abnormalities known to be associated with fetal hydrops. Whole-body anteroposterior radiographs were evaluated without knowledge of the fetal karyotype or pathological findings. Twenty-five fetuses had an abnormal karyotype, seven had a normal karyotype and in four culture failed. In the last group, the number of X, 21 and 18 chromosomes per nucleus was estimated using FISH. Radiographic analysis demonstrated that among the 16 fetuses with 45,X karyotype or a single copy of X and female phenotype, 12 had a pair of cervical ribs. Three other fetuses had a single cervical rib. Only one fetus had no cervical ribs. The last fetus had tubular hypoplasia of the aortic arch and persistent mesocolon. Twelve of the sixteen 45,X fetuses had tubular hypoplasia of the aortic arch. Seven had other cardiovascular anomalies, five had renal anomalies, and five had anomalies of intestinal rotation. Cervical rib appears to be more common than other frequently recorded associations of 45,X. It is a useful and easily demonstrated mark in the evaluation of the macerated hydropic fetus.

Female↗
PubMedDate not supplied

Axial skeleton and pituitary gland in human fetuses with spina bifida and cranial encephalocele.

The purpose of this study was to investigate the axial skeleton and the pituitary gland in fetuses with spina bifida or cranial encephalocele in order to elucidate the pathogenesis of the conditions. The findings were related to former investigations performed on normal fetuses and on fetuses with anencephaly and rachischisis. Eight human fetuses from spontaneous or therapeutic abortions, 11-28 weeks of gestational age, were investigated. Radiographs were taken of the axial skeleton and histological investigation, including immunohistochemical marking for thyroid-stimulating hormone was performed on tissue blocks of the cranial base, including the sella turcica and the pituitary gland. Radiography revealed only minor malformations in the axial skeleton and not in all cases. The types of malformations resembled those seen in anencephaly and rachischisis. Histological investigations revealed severe malformations in the sella turcica region in spina bifida and minor ones in cranial encephalocele. Pharyngeally located adenopituitary gland tissue occurred in all fetuses. Anencephaly and cranial encephalocele seemingly are conditions resulting from different expressivity of the same multifactorial process of maldevelopment involving mesoderm (skeleton), neurectoderm (spinal cord and brain), and surface ectoderm (adenopituitary gland tissue). It is suggested that the molecular biological signaling between the notochord, the scleroderm, and the surface ectoderm is disturbed in spina bifida and cranial encephalocele.

Bone and Bones↗
PubMedDate not supplied

Postmortem axial skeletal radiography can reveal fetal CNS malformations.

The routinely performed autopsy of a macerated fetus will often be of dubious value, particularly as regards the examination of the central nervous system (CNS). Former studies have demonstrated a close relationship between certain CNS malformations and axial skeletal malformations revealed radiographically. In the present report a postmortem examination of a severely macerated fetus demonstrates a transsphenoidal encephalocele. A supplementary histological examination confirmed this condition and furthermore revealed absence of the pituitary gland. The findings were related to a strongly elevated serum alphafetoprotein level in the 18th gestational week. This report emphasizes the value of postmortem axial skeletal radiography of autolyzed fetuses suspected for CNS malformations.

Adult↗
PubMedDate not supplied

Interrelation between fusions in the primary dentition and agenesis in the succedaneous permanent dentition seen from an embryological point of view.

The purpose of the present study was to elucidate the relationship between fusions in the primary dentition and the occurrence of agenesis in the succedaneous permanent dentition in a Danish child population and to elucidate this relationship from the recently described normal embryological development of the anterior parts of the human maxilla and mandible. The material included radiographs, either as intraoral film or as orthopantomograms from a total of 19 primary dentitions with a total of 21 fusions. Radiographs of the permanent dentition in the fusion regions were available for all 19 dentitions. Of 21 fusions, a total of 20 were in the mandible and one in the maxilla. In 15 cases, the fusions were between primary incisors and in six cases between lateral incisors and canines. Agenesis of a permanent lateral incisor always occurred when there had been fusion of a primary lateral incisor and a canine in the primary dentition. When fusion had been between primary incisors, there was only agenesis of an incisor in the permanent dentition in a few cases. The degree of fusion between the involved teeth was not related to the occurrence of agenesis. It is suggested that the intra-jaw differences are related to the recently reported prenatal developmental patterns of the alveoli of the incisors and canines. Moreover, it is suggested that neural crest developmental field differences between the developing maxilla and mandible may explain the inter-jaw differences in phenotypic abnormalities.

Aging↗
PubMedDate not supplied

Cranial base angulation and prognathism related to cranial and general skeletal maturation in human fetuses.

The purpose of the present study was to describe normal midsagittal craniofacial morphology in second trimester human fetuses. Measurements of the cranial base angle and the prognathism of the maxilla and the mandible were performed on radiographs of cranial midsagittal tissue blocks of 52 fetuses with a gestational age from 13 to 27 weeks. Special procedures were developed for the definitions of the nasion and sella reference points on the radiographs in the early stages of fetal development. Mean data were reported for stages of crown rump length (CRL) and maturation of the fetal cranial base (MSS), usable as reference in assessment of pathological fetal crania in reports and autopsy procedures. Regression equations were determined for the regression of the angular values on CRL, MSS, and general skeletal maturation (TNO). The cranial base angle was found to decrease significantly, and the angles of prognathism to increase significantly with increasing CRL, TNO, and MSS values. It was suggested that these simultaneous and similar changes in the three angles could be accounted for by the upwards movement of the sella point produced by a cranial displacement of the pituitary fossa caused by local cartilagenous growth and bony remodelling during the period of study. The study thus reflects the influence of cranial skeletal maturation on the early development in shape of the craniofacial complex.

Cephalometry↗
PubMedDate not supplied

Midsagittal dimensions of the prenatal human cranium.

The purpose of the present study was to analyze the linear dimensions of the cranial base and the anterior facial heights in the median plane of human fetal crania during the second trimester. The distances measured were related to gestational age (GA), crown-rump length (CRL) and maturation stages of the cranial base (MSS). The material comprised midsagittal tissue blocks of the crania from 52 normal human fetuses aged 13 to 22 weeks GA with CRL from 78 to 230 mm and cranial base maturation from MSS 3 to MSS 7. The measurements of the cranial and facial dimensions were performed on radiographs of these tissue blocks. The study confirmed previous observations regarding the dimensional increase in the linear dimensions of the cranial base and the upper facial height in the second trimester. The assessment of absolute changes was further supplemented by an analysis of the percentage changes. This analysis showed that the percentage changes from MSS 3 to MSS 7 of the linear dimensions of the cranial base and the upper facial heights were similar. On the other hand, the percentage increase in the lower anterior facial height during the second trimester was found to be much larger than that of the cranial base and the upper anterior facial height. It is suggested that this is related to the marked increase of the tooth germs during the period and the concurrent growth of the alveolar processes. Standards for normal prenatal cranial dimensions in relation to stages of maturation in the midsagittal cranial base were provided. These data may be of value for use in prenatal diagnostics.

Cephalometry↗
PubMedDate not supplied

Normal prenatal development of the human parietal bone and interparietal suture.

This study describes the prenatal human parietal bone development and interparietal suture morphology under normal conditions. The human fetal material consisted of 15 normal specimens, derived from spontaneous and therapeutically induced abortions. The study was based upon a radiographic analysis of the calvariae. Special attention was paid to the parietal tuber area, the interparietal (sagittal) suture and the frontal-parietal bone edge. The osseous morphology of these regions showed a well-defined primary ossification center at the tuber region from where bone trabeculae of uniform size and radiopacity radiated. The uniform trabeculae radiate at nearly right angles to the long axis of the sagittal suture. The bony trabeculae radiate uniformly towards the anterior fontanelle where at the peripheral border of the parietal bone radiopaque, transverse ossification corpora were observed. In the small fetuses, these corpora were located anterior to the trabeculae and in the larger fetuses close to the trabeculae. Insight into the morphological pattern in normal suture formation is essential for the further description of pathological suture morphology and for understanding normal and pathological suture development.

Cranial Sutures↗