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Biomedical subjects

L Andersen

Publications and source records attributed to L Andersen.

At least 73 records · Page 4Linked to original sources
PubMed1987

The size and composition of the submandibular glands in late-onset diabetes.

Postmortem submandibular glands from 14 patients with late-onset diabetes mellitus were examined in a histomorphometric study and were compared with 14 control glands. The diabetic glands were larger than the control glands and showed increased volume fractions of the stromal components, including vessels, and proportionally less parenchyma. These findings indicate that the increased total volume present in submandibular glands in late-onset diabetes is mainly to increased volumes of fibrous tissue, fat and vessels.

Adipose Tissue↗
PubMed1987

Chemically unrelated tumor promoters induce identical morphological changes in cultured rat oral epithelium.

By use of phase contrast microscopy, transmission and scanning electron microscopy the cytomorphological effects of different known tumor promoters (TPA, teleocidin, mezerein and anthralin) were studied and compared to the cytomorphological effects of a variety of non- or weak promoting irritants (ethylphenylpropiolate (EPP), phorbol, acetone, ethanol and dimethyl sulfoxide (DMSO]. The studies were conducted in cultures of stratifying rat tongue epithelial cells. It was demonstrated that the tumor promoters induce characteristic cytomorphological alterations, the most striking changes being elongation of the cells and formation of long cytoplasmic extensions together with induction of so-called "dark cells". The non-promoting irritants exerted well-known cytotoxic reactions like cell rounding and cell sloughing. It is suggested that the characteristic tumor promotor induced cytomorphological effects partly reflects a block of the intercellular communication and thus should be paid more attention as an important characteristic event among the pleiotropic effects exerted by tumor promoters.

Animals↗
PubMed1987

Effects of fixative composition on the ultrastructure of oral epithelium in guinea pigs.

Keratinizing epithelium from the hard palate of guinea pigs was used to investigate effects of variations in composition of fixative solutions on tissue preservation. With 2.5% glutaraldehyde as fixative, the volume of the basal intercellular spaces increased significantly when the buffer osmolality was increased by intervals of about 100 mOsm (0.05 M, 0.10 M and 0.15 M). The intercellular space volume appeared to be insensitive to differences in concentration of the fixative within the range of 2.5-5% glutaraldehyde. The preservation of mitochondria was improved by increasing the concentration of glutaraldehyde to 5% or by adding formaldehyde as a second fixative.

Animals↗
PubMed1987

Morphometric electron-microscopic investigation of the neuronal processes in the neurohypophysis in water-loaded, normal and water-deprived rats.

The neuronal processes in the neurohypophysis of the rat were analyzed by electron microscopy and morphometry after the secretion of antidiuretic hormone had been fully suppressed by water load. The water was supplied through a catheter inserted in the external jugular vein for 1.5, 2.5 and 24 h, respectively. The neurohypophysis was also examined in normal rats and rats that had been water-deprived for 72 h. The rats were fixed through chronically implanted catheters, so that at the time of fixation the animal was uninfluenced by anaesthesia and surgery. Water load increased the density of the neurosecretory granules in the endings in the zone nearest the basal lamina of the pericapillary space. The interpretation of this is that water load fills up the readily releasable pool of the neurosecretory granules. Water-deprival increased the density of dispersed microvesicles in the endings, especially in the zone near the basal lamina, and it is suggested that the dispersed microvesicles are involved in membrane recapture.

Analysis of Variance↗
PubMed1986

Parathyroid glands, calcium, and vitamin D in experimental fluorosis in pigs.

The purpose of this study was to determine whether total serum calcium, parathyroid gland structure, and/or levels of parathyroid hormone, 1,25 and 24,25 DHCC, are altered in pigs with dental and skeletal fluorosis. Eight experimental animals receiving 2 mg F-/kg b.w. per day from age 8-14 months were compared with eight controls. Concentrations of plasma fluoride and total plasma calcium were assessed at intervals throughout the experiment and during a 48 hour period at day 110-111 of the experiment. At the same time, concentrations of immunoreactive parathyroid hormone were measured using a homologous labeled antibody for porcine hormone, and a radioimmunoassay was used to assess concentrations of 1,25 DHCC and 24,25 DHCC. Parathyroid tissue volumes were assessed at the end of the experiment by quantitative histology using volumetry and point counting. Plasma fluoride increased from 0.0007 +/- 0.0001 mmol/liter to 0.0127 +/- 0.002 mmol/liter in pigs receiving fluoride. In spite of this increase, total plasma calcium remained the same throughout the experiment. Volumes of parathyroid tissue, and levels of circulating parathyroid hormone 1,25 DHCC and 24,25 DHCC, were not significantly changed. It was therefore concluded that disturbance of calcium homeostasis is not an obligatory finding in dental and skeletal fluorosis and consequently does not play an essential role in the pathogenesis of these hard tissue lesions.

Animals↗
PubMed1986

Antibody response in serum and intestine in children up to six months after a naturally acquired rotavirus gastroenteritis.

The aim of this study was to provide detailed information about the local and systemic antibody response and their relationship following a rotavirus gastroenteritis. Rotavirus-specific immunoglobulins were analyzed by enzyme-linked immunosorbent assay (ELISA). The study included 49 children referred to hospital with rotavirus gastroenteritis and 16 children with nonrotavirus gastroenteritis. The concentrations of rotavirus immunoglobulin A (IgA) in serum increased within the first 2 weeks and those of rotavirus IgG within the first month after the onset of diarrhea. Thereafter, they remained unchanged during the 6-month observation period. Rotavirus ScIg (i.e., antirotavirus immunoglobulin-containing secretory component) appeared in serum almost exclusively within 7-14 days after onset (i.e., 85% of the samples). After the first 2 weeks, rotavirus IgA could be detected in the majority of fecal samples, even up to 6 months after the disease. However, rotavirus ScIg was absent in the majority of fecal samples. The severity of illness correlated only with the increase of rotavirus IgG in serum. Conclusively, there is a longstanding immune response after a naturally acquired rotavirus gastroenteritis. Moreover, with the present methods, measurements of rotavirus IgA and IgG in serum can be safely used for serodiagnosis, even when samples are taken with 6-month interval. It is suggested that trials with rotavirus vaccines include measurements of rotavirus IgA and ScIg in serum and rotavirus IgA in feces.

Adolescent↗
PubMed1986

Morphometric electron-microscopic investigation of the neurons of the supraoptic nucleus in water-loaded, normal and water-deprived rats.

The neurons of the supraoptic nucleus (SON) in the rat have been analysed by electron microscopy and morphometry, when the secretion of the antidiuretic hormone was fully suppressed by water loading. The water was supplied through a catheter inserted in the external jugular vein for 1.5, 2.5 and 24 h, respectively. The SON was also examined in normal rats and in rats that had been deprived of water for 72 h. The rats were fixed through chronically implanted catheters, so that at the time of fixation, the animal was uninfluenced by anaesthesia and surgery. The morphology of the granular endoplasmic reticulum and the Golgi complex showed that the water load suppressed the synthetic activity and the water deprivation stimulated it. The total volumes of the vasopressin-containing neurosecretory granules (NG) were 1.6, 2.8 and 5.0 X 10(4) micron3 after a 24-hour water load, in the normal state and after 72-hour water deprivation, respectively. In steady states there was a positive correlation between the secretory activity and the content of NG in the perikaryon.

Animals↗
PubMed1985

Intestinal and serum immune response to a naturally acquired rotavirus gastroenteritis in children.

Seventeen children (mean age: 2.0 years, range: 36 days-8 years) hospitalized with acute gastroenteritis were investigated. Thirteen children had a rotavirus infection while four did not. Rotavirus serum IgA as well as ScIg, i.e., antirotavirus immunoglobulin containing secretory component, increased rapidly after rotavirus infection. While rotavirus IgA persisted in serum for at least 6 months, rotavirus ScIg disappeared from serum in less than 4 months. Rotavirus IgG could be detected in serum during the early stage of the infection and was still high after 6 months. The patients with nonrotavirus acute gastroenteritis did not show any of the above-mentioned serological hallmarks of those with rotavirus infection. The amounts of rotavirus ScIg found in serum about 1 week after the infection correlated to the amounts of rotavirus ScIg in duodenal fluid. Six months after the infection, rotavirus IgA was found in the feces of the majority of the patients while rotavirus ScIg could be detected only in one patient. The amounts of rotavirus IgA in sera and intestinal secretions showed identical patterns in the acute phase of the disease as well as after recovery. The same applied to rotavirus ScIg. These findings could be useful in future evaluations of vaccines and immunity against rotavirus infections.

Antibody Formation↗
PubMed1985

Human schistosomiasis in Ngamiland, Botswana.

To reassess the schistosomiasis problem in Ngamiland and especially in Maun area 552 primary school children and 213 adult labourers were examined with urinalysis and rectal snip. Of the pupils 80.3% were found positive for S. mansoni and 1.4% for S. haematobium; of the labourers 35.7% were infected with S. mansoni and 0.5% with S. haematobium. There was no difference between the sexes; prevalence decreased by age. In Seronga village 102 pupils were examined; 69.6% were positive for S. mansoni. The decrease in prevalence in the higher age groups may be explained by recent introduction of the agent in the area.

Adolescent↗
PubMed1984

Synthesis and anticonvulsant properties of some 2-aminoethanesulfonic acid (taurine) derivatives.

A series of 2-acylaminoethanesulfonamides were synthesized by treating the corresponding sulfonyl chlorides with ammonia, a primary, or a secondary amine. A few compounds displayed marked anticonvulsant activity in mice when tested for their potency in the maximal electroshock seizure test. The piperidino, benzamido, phthalimido, and phenylsuccinylimido derivatives were active, whereas the succinylimido, saccharinylimido, and norbornenedicarboxylimido compounds showed no activity. The interference with the sodium-independent taurine binding to mouse brain synaptic membranes was assessed to elucidate the possible mode of anticonvulsant action.

Animals↗
PubMed1984

The junction zone of human epithelium and foreign stroma. Ultrastructural observations in human oral mucosal transplants in nude mice.

This study describes ultrastructural features of epithelial-stromal junction of human buccal and palatal mucosal transplants and their outgrowths in nude mice. The investigation included transplant epithelium overlying human connective tissue in 27 cases, epithelial outgrowth formed over murine connective tissue in 33 cases, and over Millipore filter in 12 cases. The epithelial-stromal junction of the transplants differed from the normal state only in the presence of lamina densa loops projecting into the connective tissue and in lamina densa interruptions and duplications. In contrast the epithelial outgrowths demonstrated flattening of epithelial basal cells, lack of proximal epithelial cell projections, lack of complete hemidesmosome complexes, lack of distinct lamina densa, and lack of anchoring fibrils. It is suggested that these changes may be due to lack of necessary interaction between the human epithelium and the foreign stroma.

Adolescent↗
PubMed1981

Leukoplakia-like lesions developing in patients with oral discoid lupus erythematosus.

In a long-term follow-up of 52 patients with oral lesions of discoid lupus erythematosus (DLE) 8 patients showed a gradual transition of the typical DLE lesions to lesions which closely resemble leukoplakia. Histopathologically and immunopathologically the leukoplakia-like lesions generally showed features similar to those in leukoplakias not preceded by DLE. Ultrastructurally, the leukoplakia-like lesions showed the presence of cytoplasmic tubular structures in vascular endothelium in two out of three patients examined. The leukoplakia-like stage is considered to be an inactive or scar-like stage, which may be the mucous membrane counterpart of the atrophic scars following DLE lesions of the skin. A primary examination of a DLE patient presenting oral lesions at the leukoplakia-like stage may result in an incorrect diagnosis. Therefore, when investigating patients with leukoplakias, they should be questioned on previous or present skin lesions as well as symptoms of systemic lupus erythematosus.

Adult↗