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Biomedical subjects

B Fischer-Hansen

Publications and source records attributed to B Fischer-Hansen.

12 recordsLinked to original sources
PubMed2001

Expression of nitric oxide synthases and effects of L-arginine and L-NMMA on nitric oxide production and fluid transport in collagenous colitis.

BACKGROUND AND AIMS: Luminal nitric oxide (NO) is greatly increased in the colon of patients with collagenous and ulcerative colitis. To define the source and consequence of enhanced NO production we have studied expression of NO synthase (NOS) isoforms and nitrotyrosine in mucosal biopsies from these patients. In addition, effects on colonic fluid transfer caused by manipulating the substrate of NOS were studied in patients with collagenous colitis. PATIENTS: Eight patients with collagenous colitis, nine with active ulcerative colitis, and 10 with uninflamed bowel were included. METHODS: Expression of NOS isoforms was quantified by western blotting. Inducible NOS (iNOS) and nitrotyrosine were localised by immunohistochemistry. Modulation of NOS activity by topical N(G)-monomethyl-L-arginine (L-NMMA) or L-arginine was assessed during perfusion of whole colon. Plasma and perfusate nitrite/nitrate (NOx) was measured by Griess' reaction. RESULTS: Both in collagenous and ulcerative colitis, expression of iNOS was 10(2)-10(3) higher (p<0.001) than in uninflamed bowel and localised primarily to the epithelium. Endothelial NOS was evenly expressed in all groups while neuronal NOS was undetectable. Nitrotyrosine was markedly expressed in active ulcerative colitis but rarely detected in collagenous colitis and never in uninflamed bowel. In collagenous colitis, the output of NOx was markedly increased compared with uninflamed bowel (283 (58) v <37 nmol/min; p<0.01) and fluid was net secreted. L-NMMA reduced the output of NOx by 13-66% (95% confidence intervals) and secretion of fluid by 25-109% whereas L-arginine increased the output of NOx by 3-39% and secretion of fluid by 15-93%. CONCLUSIONS: In collagenous colitis, as opposed to ulcerative colitis, upregulation of iNOS occurs in the absence of nitrotyrosine formation and mucosal damage. Excess generation of NO may be the primary cause of diarrhoea in this condition.

Adult↗
PubMed2001

Craniofacial tissues including tooth buds in fetal hypohidrotic ectodermal dysplasia.

OBJECTIVE: Hypohidrotic ectodermal dysplasia (HED) comprises defects in hair, teeth, and sweat glands. Disturbances in other ectodermal tissues have been associated with the condition. Our objective was to examine ectodermal craniofacial structures histologically in a fetus with HED and to compare the findings to similar structures in normal control fetuses. MATERIALS AND METHODS: A male fetus diagnosed with HED was therapeutically aborted in the 15th week of gestation. One male and two female healthy fetuses were used as normal controls. All fetuses were examined with parental consent, and had comparable sizes. Their bone maturation stage in the hand was identical. Tissue blocks from the craniofacial region were excised from all fetuses and prepared for histological analysis (formalin fixed, stained with toluidine blue or Alcian blue). The tissues examined were: tooth buds, skin and skin appendages, oral mucosa including minor salivary glands, major salivary glands, lacrimal glands, and adenohypophysis. RESULTS: Fewer tooth buds, minor salivary glands, and hair follicles were observed in the HED fetus as compared to controls. The structures of the epidermal components in the developing HED organs were loose and disorganised. The adhesion between the ectodermal and mesenchymal organ components in the HED fetus seemed to be disturbed.

Ectodermal Dysplasia↗
PubMed1992

n-3 fatty acids in adipose tissue and coronary artery disease are inversely related.

The incidence of coronary heart disease is supposedly influenced by dietary fish-oil intake. The purpose of this study was to investigate the possible beneficial effect of fish consumption on coronary atherosclerosis. Adipose-tissue biopsies and segments of coronary arteries were sampled from 40 consecutive autopsies. Degree of coronary artery disease was estimated quantitatively by morphometry, and the fatty acid composition of adipose tissue was analyzed with gas-liquid chromatography. The group with the highest degree (68-92% stenosis, n = 13) of coronary artery disease had lower concentrations of docosahexaenoic acid in adipose tissue than did the group with the lowest degree (23-53% stenosis, n = 13) of coronary artery disease (P less than 0.05). Multiple-regression analysis showed that the degree of coronary artery disease was dependent on docosahexaenoic acid in adipose tissue (P less than 0.01) and body weight (P less than 0.05). The study supports the hypothesis that fish consumption is associated with a reduced risk of coronary heart disease.

Adipose Tissue↗
PubMed1980

Eaton-Lambert syndrome and malignant thymoma.

Eaton-Lambert syndrome is most frequently associated with small-cell carcinoma of the lung. We describe the first case of this disorder in a patient with malignant thymoma. Guanidine treatment had no clinical or electrophysiologic effects.

Female↗
PubMedDate not supplied

Prenatal development of the human osseous temporomandibular region.

The purpose of the present study was to describe the sequence in which the lateral cranial base ossifies, particularly in the temporomandibular region. Charting the ossification sequence in the lateral normal cranial base is important for evaluating deviations in pre- and postnatal temporomandibular development. The material consisted of 74 normal human fetuses (crown-rump length = 25-228 mm). The period investigated covers the interval from the early start of ossification at 8 weeks gestational age to the occurrence of a complex ossification pattern at 21 weeks gestational age. Ossification of the cranial base in the sagittal plane is assessed mainly by radiography. The findings are confirmed by marking structures before X-ray, devisceration, and histology. This investigation confirms previous findings concerning regularity in cranial ossification sequences. In addition, the ossification in the temporomandibular region is divided into eight developmental stages according to the pattern of ossification. Thus, a developmental reference material has been established based on the following sequence in ossification of the cranial base (including the mandible and the zygomatic bone): mandible, maxilla, medial pterygoid process of the sphenoid bone, the horizontal part of the frontal bone, the zygomatic bone, the zygomatic arch of the temporal bone, the squamous part of the temporal bone and the occipital squama followed by ossification in the greater wing of the sphenoid bone, the tympanic ring, the occipital condyle, the minor wing of the sphenoid bone (anterior clinoid process), and the lateral part of the postsphenoid bone.(ABSTRACT TRUNCATED AT 250 WORDS)

Embryonic and Fetal Development↗
PubMedDate not supplied

Development of the basilar part of the occipital bone in normal human fetuses.

The present study aims to investigate the normal maturity and growth of the basilar part of the occipital bone evaluated radiographically and histochemically during the first half of prenatal life. The material consisted of cranial bases from 49 normal human fetuses and, in addition, three separate occipital bones deviscerated from normal fetuses. The normal development of the basilar part of the occipital bone was divided into five maturity stages (OB-I to OB-V). Microscopic investigation confirmed the macroscopic findings described. For each stage the ventro-dorsal dimension of the occipital bone component was measured (LEN). The stages of (OB-I to OB-V) were related to gestational age (AGE), crown-rump length (CRL), LEN, and to the length of the humeral bone (HL). Close accordance was registered between OB stages and length values of the basilar part of the occipital bone, LEN, and length of the humeral bone, HL. A highly significant positive correlation was found between LEN and the parameters AGE, CRL, and HL values (P < 0.001). Standards for normal development of the basilar part of the occipital bone are considered important for evaluation of the pathological prenatal development of the cranial base.

Gestational Age↗
PubMedDate not supplied

The adenohypophysis and the cranial base in early human development.

The purpose of the present study is to chart the normal human development of the adenohypophyseal part of the pituitary gland and of the cranial base, with special attention given to the possible presence of pharyngeal remnants of adenohypophyseal tissue. From 31 human embryos and fetuses (7-21 weeks of gestation) midsagittal, paraffin-embedded tissue blocks of the cranial base, including the pituitary gland and the pharyngeal wall, were investigated histologically. The identification of adenohypophyseal tissue included immunohistochemical methods. In early stages, the adenohypophysis of the pituitary gland. From this stage in development adenohypophyseal tissue is not demonstrated pharyngeally. The cartilaginous cranial base is visible in its full antero-posterior extent before ossification starts. Cranio-pharyngeal canals are not registered in the cranial base. This study intends to define a standard for subsequent autopsy descriptions of the pituitary gland region in craniofacial malformations.

Autopsy↗
PubMedDate not supplied

Growth in the lateral part of the human skull during the second trimester.

The aim of the present study was to report dimensional changes in the lateral part of the prenatal human skull during the second trimester. The sample comprised 37 fetuses obtained in connection with requested autopsy. Gestational ages (GA) were available for 27 fetuses, ranging from 13 to 24 weeks. Crown-rump lengths (CRL) of 23 fetuses ranged from 78 to 228 mm. For 21 fetuses both CRL and GA were available. After excision of the midsagittal segment of the skulls by two paramedian sections from the frontal bone to the foramen magnum through the optic foramina, an incision was made through the middle of the occipital squama, bisecting the skull. The present study was based on the skull components of the resulting 74 lateral cranial tissue blocks. The tissue blocks were radiographed with a Hewlett Packard Faxitron unit. Seven reference points were digitized from each film and eight linear dimensions were calculated. Method errors ranged from 0.12 mm to 0.52 mm. The dimensions were related to crown-rump length (CRL) and lateral segment developmental stages (LSS). The increases in the linear dimensions of the anterior part of the lateral skull segments were similar to those found previously for the median skull segment. The dimensions of the anterior part of the lateral skull segments were found to increase by 150% during the second trimester, while those of the posterior part increased by 100% during the same period. Between maturity stages LSS 4 and 5 the dimensions increased by 30-50%, whereas less increase was observed between stages 5, 6, 7, and 8. This reduction was attributed to the progressive ossification of the cranial base. The almost horizontal distance from the mandibular condyle (condylion) to the anterior tympanic ring did not change significantly during the second trimester. Comparison of the bilateral skull segments showed no systematic asymmetry, but a significant individual biological variability in symmetry with standard deviations of 0.7-1.8 mm was found.

Cephalometry↗
PubMedDate not supplied

Human fetal pituitary gland in holoprosencephaly and anencephaly.

The normal prenatal development of the human pituitary gland and the gland-supporting sella turcica has recently been investigated. The sella turcica area constitutes a developmental boundary area in the cranial base. Posterior to the area the cranial base has developed close to the notochord, and anterior to the region the cranial base development is dependent chiefly on neural crest cell migrations. In the present study the sella turcica region was analyzed in two fetuses with holoprosencephaly (cyclopia and median cleft) and four fetuses with anencephaly combined with rachischisis in the neck region (GA 16-20 weeks). The sella turcica region was investigated radiologically and histologically. Adenohypohyseal gland tissue was localized by immunohistochemical hormonal marking. In both types of malformation an open craniopharyngeal canal was seen in the base of the sella turcica with adenohypophyseal glandular tissue located in the sella turcica, in the canal, and in the pharyngeal connective tissue at the external side of the cranial base. In conclusion, severe malformations of the pituitary gland occur in both holoprosencephaly, which is a polytopic field defect located anterior to the sella turcica, and in anencephaly associated with notochordal insufficiency posterior to the sella turcica. This might indicate that the sella turcica area, bounding different developmental fields, is involved in various craniofacial malformations. It is consequently recommended that examination of the pituitary gland should become a part of the routine autopsy of prenatal material when malformations in the face, brain, and cranial base occur.

Anencephaly↗