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Biomedical subjects

K Andersen

Publications and source records attributed to K Andersen.

At least 199 records · Page 11Linked to original sources
PubMed1982

Myocardial preservation during anoxic arrest. Experimental model ventricular fibrillation.

An experimental model with anaesthetized healthy mongrel dogs on extracorporeal circulation is described. Anaesthesia and cardiopulmonary bypass are the same as used in clinical practice. Various methods of myocardial preservation were investigated and their protective effect was judged by cardiac performance after termination of 60 min of anoxic arrest. In this study, the first part of an experimental series, electrically-induced fibrillation during 60 min of normothermic and local hypothermic anoxic arrest was investigated. In group I, the hearts were fibrillated immediately after cross-clamping. In group II, which served as controls, the hearts were allowed to fibrillate spontaneously after aortic cross-clamping. All the hearts in group I went into an ischaemic contracture, whereas those in group II showed a 50% recovery, but with a strongly reduced cardiac performance after termination of anoxic arrest and cardiopulmonary bypass. Measurements of myocardial surface pH demonstrated a rapidly developed acidosis during the period of anoxic arrest. The most impressive finding by light microscopy was pronounced myocardial oedema. External cooling by 4 degrees C glucose 5.5% continuously flushed into the pericardial sac in combination with electrically-induced fibrillation proved to be ineffective as a protective method. None of the eight dogs in this group survived. External cooling combined with intraventricular injection of 4 degrees C glucose 5.5% seemed to protect the hearts against ischaemic damage, insofar that all six hearts in this group were able to take over the circulation after declamping. The working capacity was, however, impaired and a relatively long period of mechanical support and stimulation with inotropic drugs was necessary.

Animals↗
PubMed1981

Hydrogenase genes.

For a variety of reasons, including the potential industrial applications of hydrogenase, we are interested in the isolation and analysis of hydrogenase genes. In a program focusing on the hydrogen bacterium A. eutrophus H1 and E. coli, we have developed a preliminary concept of the interaction of hydrogenase in cellular metabolism, constructed mutants deficient in hydrogenase activity, and begun the isolation of hydrogenase genes utilizing the technology allowing the in vitro manipulation of DNA. We hope to pursue this project to its ultimate goal: the analysis of the molecular mechanisms involved in the control of expression of these genes and the development of the ability to manipulate the production of hydrogenase.

Alcaligenes↗
PubMed1981

Fine structure and FSH binding of Sertoli cells in the blue fox (Alopex lagopus) in different stages of reproductive activity.

A clearly different Sertoli cell morphology was found in the immature blue fox and in the adults in and out of season. Immature cells had small, basally, located nuclei rich in peripheral heterochromatin, and few cytoplasmic organelles. Sertoli cells from adults in season had basally located, large, convoluted nuclei with homogenous nucleoplasma and prominent nucleoli. The basal and intermediate parts of the cytoplasm contained an extensively developed ER, numerous mitochondria, free ribosomes, lipid droplets and residual bodies, while the apical cytoplasm showed few distinct structures. In Sertoli cells from adults out of season the nuclei were dislocated towards the lumen, and apart from numerous dilated cisternae of ER, there were generally fewer organelles, but more glycogen particles. A marked rise in FSH binding was found towards the breeding season.

Aging↗
PubMed1981

Silver nitrate pleurodesis in spontaneous pneumothorax.

Pleurodesis provoked by instillation of silver nitrate as prevention against recurrence in primary spontaneous pneumothorax has been used for many years in the Department of Thoracic Surgery, Gentofte Hospital, University of Copenhagen. The treatment was originally instituted on a theoretical empiric basis. In a prospective, controlled investigation of pleurodesis versus simple drainage the empiric observations have been confirmed. With simple drainage we found ipsilateral recurrence of pneumothorax in 45%, while no recurrences in the pleurodesis group were found during an observation period of 5-19 months. The difference was statistically significant. The therapeutical gain using pleurodesis was 45% +/- 30%. Silver nitrate pleurodesis results in a longer hospitalization, raises the number of pleurocentesis because of increased pleural effusion and results in more pain than simple drainage. It is, however, our experience that the considerable therapeutical gain more than compensates for these negative effects. We recommend pleurodesis as the treatment of choice in primary spontaneous pneumothorax in patients with only tiny blebs on the surface of the lungs.

Adolescent↗
PubMed1980

Familial occurrence of papillary thyroid carcinoma.

We report two kindreds from northern Norway with 7 and 4 cases of papillary thyroid carcinoma in otherwise healthy, nonirradiated subjects. While histologic features were comparable the patient's age at the time of diagnosis was lower and lymph node metastases were more frequent in familial than in nonfamilial cases of papillary thyroid carcinoma from the same region. We conclude that genetic factors can predispose the patient for development of papillary thyroid carcinoma. The high local incidence may be due to interaction between susceptibility gene(s) and environmental factors.

Adolescent↗
PubMed1980

Immediate hemodynamic effect of pharmacological doses of methylprednisolone in dogs, and the influence of speed of injection.

Reports of sudden death of patients during i.v. administration of methylprednisolone (M.P.) prompted the present study of the hemodynamic effect of M.P. given i.v. to dogs. Fifteen healthy, mongrel dogs were anesthetized with thiomebumal, fentanyl, droperidol, pancuronium and N2O/O2. With ventilation and circulation in steady state, M.P. 30 mg/kg b.w. was given i.v. either as a push bolus (n=7) or over a 5-min period (n=8). In the bolus group, mean aortic pressure (MAP) and systemic vascular resistance (SVR) had decreased to 72 and 60%, respectively, 1 min after the start of the steroid injection, while heart rate (HR), cardiac index (CI), mean pulmonary arterial pressure (MPAP) and left ventricular work (LVW) had not changed significantly. In the 5-min group, the HR increased by 23%, while the other parameters were unchanged during the injection period. Within 5 min after the termination of the steroid injection all hemodynamic parameters had returned to pre-injection levels in both groups. Sodium, potassium, magnesium, protein and calcium in serum were unchanged in both groups during the injection period and in the following 15 min. A significant, transient fall in ionized calcium was observed in all six dogs in which this ion was measured. It was concluded that rapid i.v. injection of pharmacological doses of M.P. in hemodynamically stable, anesthetized dogs causes immediate, transient decreases in SVR and MAP. The mechanisms may be an alpha adrenergic blocking action or a direct effect on the muscles in the peripheral vessels, combined with a negative inotropic effect on the myocardium, possibly mediated through an impeded calcium release.

Anesthesia, Inhalation↗
PubMed1979

Mutations altering the catalytic activity of a plant-type ribulose biphosphate carboxylase/oxygenase in Alcaligenes eutrophus.

Use of a bacterial system has allowed the isolation of several mutationally altered species of ribulose-1,5-bisphosphate carboxylase/oxygenase having a wide range of catalytic activities. Biochemical and serological techniques were used to classify the mutant strains into three groups: (1) no detectable ribulose-1,5-bisphosphate carboxylase/oxygenase protein present (both subunits missing); (2) mutant strains having ribulose-1,5-bisphosphate carboxylase/oxygenases with lowered specific activities; and (3) mutant strains producing large quantities of catalytically inactive ribulose-1,5-bisphosphate carboxylase/oxygenase.

Alcaligenes↗
PubMed1978

The helminths in the gut of perch (Perca fluviatilis L.) in a small oligotrophic lake in southern Norway.

A total of 311 perch were examined for gut parasites during the period from April 1972 to December 1973. Four different metazoan parasites were found; Proteocephalus percae (Müller, 1780), Bunodera luciopercae (Müller, 1776), Acanthocephalus lucii Müller, 1776 and Camallanus lacustris Zoega, 1776. B. luciopercae and P. percae exhibited similar seasonal cycles in appearance and abundance. They were both absent from the fish population during June/July. A. lucii and C. lacustris on the other hand had a peak in infection intensity and incidence during the summer and autumn months. From September/October one year to May/June the following year B. luciopercae was the dominating parasite species showing the highest incidence (approximately 95%) and intensity (a mean of about 25 parasites per infected fish). When 2 times 2 contingency tests were applied on the material from this period a significant negative correlation between the presence of P. percae and A. lucii could be pointed out while there was no correlation between the presence of any of the other 3 parasite species.

Acanthocephala↗