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Biomedical subjects

G Hansson

Publications and source records attributed to G Hansson.

At least 91 records · Page 5Linked to original sources
PubMed1987

Immunohistochemical study of nasal mucosa in patients with selective IgA deficiency.

Fifteen nasal biopsy specimens from adult patients with selective IgA deficiency were examined in a 'blind' immunohistochemical study for the presence of immunocytes producing various immunoglobulin (Ig) classes. Three groups of patients could be identified. One group had a predominance of IgG- and IgM-producing cells in their nasal mucosa, a second group revealed mainly IgG- and IgD-producing cells, and a third group had very few mucosal immunocytes. The clinical examinations showed that upper respiratory tract infections were most common in patients with few immunocytes while such infections were least common in patients with predominance of IgG and IgM immunocytes. Our results indicated that IgM, in contrast to IgD, acts as a compensatory secretory Ig in some patients with selective IgA deficiency.

Adolescent↗
PubMed1987

The clinical condition of IgA-deficient patients is related to the proportion of IgD- and IgM-producing cells in their nasal mucosa.

Nasal biopsy specimens from 15 adult patients with selective IgA deficiency but normal IgG-subclass levels were examined by immunohistochemistry for the presence of immunocytes producing various Ig isotypes. The mucosal samples were completely IgA-deficient except in two cases where 0.9% and 8.4% IgA cells were found, respectively (normal, 69.8%). Numerous IgG- (mainly IgG1-) producing cells were present in 10 samples; in five of these there were additional IgM- but virtually no IgD-producing cells, whereas in the other five a marked dominance of the IgD over the IgM isotype was seen. The latter category of patients had more upper airways infections (recurrent acute rhinosinusitis, otitis media, and tonsillitis) than the former, who had no recurrent upper respiratory tract infections except one patient with recurrent acute rhinosinusitis. The five remaining samples, which contained very few Ig-producing cells, were derived from patients with even more frequent infections than those showing IgD predominance. Our results indicate that IgM acts as a compensatory secretory Ig in the upper respiratory tract of some IgA-deficient subjects. However, immunoregulatory events favouring local IgD responses apparently do not support mucosal defence satisfactorily, either because local production of IgM is hampered or because IgD (which is not a secretory Ig) blocks complement-dependent reactions mediated by IgG and IgM antibodies within the mucosa.

Adolescent↗
PubMed1986

Benign and malignant thyroid nodules after neck irradiation.

A total of 444 persons were examined for the presence of thyroid nodules on average of 43 years after having been treated with x-rays for cervical tuberculous adenitis. Of this total, 101 subjects had undergone surgery for thyroid nodules: 25 for carcinoma (6%) and 76 for benign nodules (17%). Carcinoma occurred with the same frequency in multinodular and uninodular glands. Because of the uneven age distribution in the current series, it could not be decided whether there was a higher susceptibility of the young thyroid to the induction of thyroid carcinoma or benign nodules. The dosage range for the whole series was 0.40 to 50.90 Gy (40-5090 rad). There was a positive correlation between the absorbed radiation dose and the probability of developing benign and malignant thyroid nodules, even after doses of 20 Gy or more. The risk of developing thyroid carcinoma was equal for men and women, while the female-to-male ratio for benign nodules was 2.9:1, indicating that risk factors associated with females are of less importance in irradiated than in nonirradiated populations. The median latency for carcinoma was 40 years, suggesting that the increased risk of thyroid carcinoma after irradiation remains for the rest of the patient's life.

Adenocarcinoma↗
PubMed1986

Oxidation of 1,4-dihydropyridines by prostaglandin synthase and the peroxidic function of cytochrome P-450. Demonstration of a free radical intermediate.

Oxidation of 1,4-dihydropyridines by the hydroperoxidic function of cytochrome P-450 and prostaglandin synthase was investigated using felodipine as a model substance. Nifedipine and the 2,6-dichlorophenyl analogue of felodipine were used in some experiments with similar results. Felodipine was metabolized to a pyridine metabolite in vitro when incubated with liver microsomes and cumene hydroperoxide, as well as with ram seminal vesicle microsomes and arachidonic acid. The oxidation of 1,4-dihydropyridines is proposed to proceed via formation of a free radical intermediate, judging from EPR analysis with the spin trap POBN. When reduced glutathione was added the EPR signal was decreased as well as the formation of the pyridine metabolite while an oxidation of glutathione was observed. This effect was due to a reduction of the radical intermediate back to felodipine by glutathione. Felodipine interacts with the hydroperoxidase activity of prostaglandin synthase, since the pyridine metabolite was formed also when 15-hydroperoxyeicosatetraenoic acid was used as a substitute for arachidonic acid. Indomethacin could only inhibit the metabolism of felodipine when arachidonic acid was used as substrate. The cooxidation of felodipine by prostaglandin synthase is associated with an increased metabolism of arachidonic acid. This was further supported by a stimulated oxygen consumption and an increased formation of prostaglandin E2.

Animals↗
PubMed1986

Primary parathyroid hyperplasia of water-clear cell type. Transformation of water-clear cells into chief cells.

An exceptional case of water-clear cell hyperplasia (WCCH) of the parathyroid glands is presented. Parathyroid tissue was excised at three operations during a period of twenty years before the patient eventually became normocalcemic. Microscopic evaluation of the parathyroids from the first operation showed typical WCCH-findings. However, the parathyroid tissue excised at the last operation was composed of chief cells. There were calcifications and even bone formation. A pigment with the staining and electron-microscopic characteristics of lipofuscin was found in abundance. There were also a few oxyphils. This case shows that clear cells, originally derived from chief cells, can transform into chief cells again.

Adult↗
PubMed1986

Quinolones affect thymidine incorporation into the DNA of human lymphocytes.

The incorporation of [3H]thymidine into DNA was increased in phytohemagglutinin-stimulated human lymphocytes exposed to four of the new quinolone derivatives (ciprofloxacin, norfloxacin, ofloxacin, and A 56620) at concentrations achievable in clinical situations. However, proliferation of phytohemagglutinin-stimulated lymphocytes was not influenced by ciprofloxacin at concentrations of 0.5 to 10 micrograms/ml.

DNA↗
PubMed1986

Reoperation in the treatment of asymptomatic metastasizing medullary thyroid carcinoma.

Eleven patients who continued to have elevated calcitonin (CT) levels after thyroidectomy and central node dissection for medullary carcinoma of the thyroid gland (MCT) were subjected to additional surgery. Metastatic MCT was found in the excised tissue from each patient. Normalization of CT values was obtained in four patients who had a few microscopic, unilateral metastases. In these patients an average of 13 normal lymph nodes were excised at reoperation for each metastasis. The results of the reoperative series demonstrate that it is possible, with meticulous neck dissection, to normalize CT levels in patients with microscopic metastases from MCT. Metastases that can be seen or palpated are always associated with microscopic lymph node metastases. Removal of such microscopic metastases is probably the key to achieving normal postoperative CT levels.

Adult↗
PubMed1985

Hyperparathyroidism subsequent to neck irradiation. Risk factors.

A follow-up examination of 444 persons treated with x-rays for tuberculous cervical adenitis was performed to determine if the risk for hyperparathyroidism (HPT) following radiation exposure can be related to the age at treatment, the dose of x-rays, or the sex of the patient. The overall incidence of HPT was 14%. There was no definite age-dependent difference in susceptibility to the induction of HPT. The doses of radiation among the 63 subjects who developed HPT ranged from 0.6 to 45.7 Gy (60-4570 rad). There was a statistically significant positive correlation between the dose of radiation and the probability of developing HPT. After doses of 14 Gy (1400 rad) or more 29% of the subjects had developed HPT. After neck irradiation women had twice the relative risk of men of developing HPT. This sex ratio was lower than in the series of nonirradiated HPT patients treated at the same institution during the time of the follow-up study.

Adolescent↗
PubMed1983

Allergen challenge of lung tissue from asthmatics elicits bronchial contraction that correlates with the release of leukotrienes C4, D4, and E4.

The leukotrienes C4, D4, and E4, previously referred to as slow reacting substance of anaphylaxis, elicited long-lasting contractions of bronchi isolated from two birch pollen-sensitive asthmatics. The leukotrienes were 1,000 times more potent on a molar basis than was histamine or prostaglandin F2 alpha. Moreover, allergen released leukotrienes C4, D4, and E4 from the lung tissue of the asthmatics in amounts that appeared to correlate well to the anaphylactic bronchial contraction. Irrespectively of whether the lung was stimulated with specific allergen, the ionophore A23187 or 14C-labeled arachidonic acid, 15-hydroxyicosatetraenoic acid, and other lipoxygenase-derived monohydroxy acids were the major metabolites of arachidonic acid in the lung, and thromboxane A2 and prostaglandin I2 were the predominant cyclooxygenase products identified. However, cyclooxygenase inhibition with indomethacin had no effect on the contraction response to antigen in the bronchi, whereas, in the presence of U-60257, an inhibitor of leukotriene biosynthesis, the allergen neither released leukotrienes from the lung nor caused bronchial contraction. These findings indicate that leukotrienes C4, D4, and E4 are major mediators of allergic bronchoconstriction in man.

Allergens↗
PubMed1983

Screening of children with congenital dislocation of the hip joint on the maternity wards in Sweden.

In Sweden screening for congenital dislocation of the hip joint (CDH) on the maternity wards was commenced in the 1950s. Of the estimated number of cases with CDH approximately 50% are diagnosed on the maternity wards and 80% during the first 6 months of life. Of the children "missed" at the primary screening on the maternity wards a substantial number have been premature babies treated at the intensive care unit postpartum. X-ray examination at the age of 1.5-3 months has been a helpful tool to reveal failure of early abduction treatment, which has been difficult to detect by clinical examination. Children with neonatal hip instability and a family history of CDH seem to represent a subgroup with an increased risk of failure of primary treatment and may need prolonged abduction treatment. The von Rosen splint has proved to be a reliable brace if used properly. If abduction treatment is commenced already during the first few days of life the risk for avascular necrosis is very low--1%.

Braces↗
PubMed1982

A novel leukotriene produced by stimulation of leukocytes with formylmethionylleucylphenylalanine.

Stimulation of human polymorphonuclear leukocytes with the chemotactic peptide formylmethionylleucylphenylalanine led to the formation of a novel leukotriene: 5(S),12(R)-dihydroxy-6,8,10,14-eicosatetraen-1,20-dioic acid. This dihydroxydicarboxylic acid is derived from omega-oxidation of 5(S),12(R),dihydroxy-6,8,10,14-eicosatetradienoic acid (leukotriene B4). The intermediate 5(S),12(R),20-trihydroxy-6,8,10,14-eicosatetraenoic acid was also isolated from these incubations. The two metabolites of leukotriene B4 exhibit chemotactic properties for human polymorphonuclear leukocytes but are less active in this respect than the parent compound.

Arachidonic Acids↗