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Biomedical subjects

K Larsen

Publications and source records attributed to K Larsen.

At least 109 records · Page 6Linked to original sources
PubMed1986

Isolation and characterization of human factor VIII: molecular forms in commercial factor VIII concentrate, cryoprecipitate, and plasma.

Human factor VIII has been isolated from a high purity factor VIII concentrate by immunoaffinity chromatography and HPLC on Mono Q gel. Two fractions of factor VIII were obtained with a specific activity of approximately equal to 7000 units/mg. The major fraction contained eight peptide chains of 200, 180, 160, 150, 135, 130, 115, and 105 kDa plus one doublet chain of 80 kDa. The minor fraction contained one peptide chain of 90 kDa plus the chain of 80 kDa. Both fractions were activated by thrombin to the same extent. Amino-terminal amino acid sequence analysis was performed on the 180-kDa, 130-kDa, and 90-kDa chains and showed an identical amino-terminal sequence in these chains. Each chain from 200 kDa to 90 kDa was linked to one 80-kDa chain by a metal-ion bridge(s). Studies on factor VIII in plasma and cryoprecipitate, prepared and gel filtered in the presence of protease inhibitors, showed that one 200-kDa plus one 80-kDa chain were the only or dominating chains in the materials and may represent native factor VIII. The results indicated that all chains from 180 kDa to 90 kDa are fragments of the 200-kDa chain. All of these more or less fragmented chains form active factor VIII complexes with the 80-kDa chain.

Amino Acid Sequence↗
PubMed1986

Impact of prospective payments on a tertiary care center receiving large numbers of critically ill patients by aeromedical transport.

To determine the economic impact of federal prospective payments and the potential effect if private insurance payers were to implement similar prospective payments, we examined payments under Medicare diagnosis-related grouping (DRG) reimbursement policies for 105 Medicare and 357 non-Medicare patients admitted to a tertiary care center via air transport. Among the 105 Medicare patients, the average length of stay was 11.4 days and the mortality rate was 24%. Hospital charges exceeded DRG reimbursement for 74% of Medicare patients. A comparison of previous Medicare payment policies to current federal DRG reimbursement resulted in a revenue loss to the hospital of $667,229 ($6335 per patient). For the 357 non-Medicare patients, the average length of stay was 10.8 days, the mortality rate was 10%, and hospital charges exceeded Medicare DRG reimbursement for 78% of the patients. Implementation of DRG-like payments by non-Medicare insurers would create a hospital revenue loss of $2,493,048 ($6983 per patient). We conclude that unless current and planned prospective payment policies are modified, the use of aeromedical transport services to recruit large numbers of critically ill patients to tertiary care centers is economically prohibitive.

Aircraft↗
PubMed1986

Aging decreases the sensitivity of rat cortical synaptosomes to calcium ionophore-induced acetylcholine release.

The capacity of calcium ions to trigger acetylcholine release was studied in cerebral cortical synaptosomes from adult (6-month-old) and senescent (24-month-old) rats, using a calcium ionophore, A23187, that bypasses voltage-sensitive calcium channels. The potency but not the efficacy of the A23187 was reduced with respect to releasing acetylcholine (ACh) in the aged animals. There was no age-related difference in the synthesis of ACh or potency of the ionophore with respect to increasing 45calcium uptake. These results suggest that aging reduces the sensitivity of cerebral cortical nerve terminals to calcium-triggered ACh-release.

Acetylcholine↗
PubMed1985

Immunological comparison of glyoxalase I from yeast and mammals and quantitative determination of the enzyme in human tissues by radioimmunoassay.

Antibodies to glyoxalase I from yeast, rat liver, porcine erythrocytes and human erythrocytes were raised in rabbits. Gel precipitation and immunotitration experiments demonstrated that the mammalian enzymes were immunologically related, but distinct from the yeast enzyme. Fab fragments of the antibodies to human glyoxalase I did not inhibit the catalytic activity, indicating that the antigen binding sites were not directed towards the active site of the enzyme. A radioimmunoassay for glyoxalase I was developed. Quantitative analysis of human adult as well as fetal organs demonstrated that glyoxalase I was present in a concentration of approximately 0.2 micrograms/mg protein in most human tissues.

Adult↗
PubMed1985

Etomidate infusion and adrenocortical function. A study in elective surgery.

The adrenocortical response to a short tetracosactrin (Synacthen) test was studied in 11 patients receiving either etomidate infusion or thiopentone infusion used to maintain anaesthesia for abdominal hysterectomy. Pethidine was used as the narcotic component. The results showed that etomidate infusion (median 28.5 ug/kg/min) completely blocked the adrenocortical response to corticotropin stimulation for at least 24 h after surgery. No suppression was found in patients receiving thiopentone infusion. It is concluded that etomidate cannot be recommended for routine induction and maintenance of anaesthesia.

Adrenal Cortex↗
PubMed1984

Cervical intervertebral disc calcification in childhood.

A case of cervical intervertebral disc calcification in a child is presented. The condition is rare, the aetiology unknown and the prognosis good. Possibility for differential diagnosis are discussed and the importance of the otolaryngologist having a knowledge of the condition is emphasized.

Calcinosis↗
PubMed1984

Intraoral lipoma. A rare cause of dysphagia.

Lipomas of the oral cavity are rare and in most cases asymptomatic. A case of lipoma in the floor of the mouth in a 89-year-old man, causing severe dysphagia and difficulty with speech, is presented. After surgical excision of the lipoma, the symptoms disappeared. Histologically, lipomas are composed of mature fat cells. Their aetiology is uncertain. Recurrence after surgical excision is unusual.

Aged↗
PubMed1984

Kinetics of white spirit in human fat and blood during short-term experimental exposure.

Seven volunteers were exposed to 100 p.p.m. white spirit (99% paraffins C8-C12) 6 hrs daily in 5 days. The mean concentration of white spirit after 5 days of exposure was 41.1 mg/kg fat (Friday afternoon). On the following Monday morning, the concentration was 31.7 mg/kg, i.e. only 23% had been eliminated during the exposure-free weekend. The estimated mean and median half-life was 7 and 8 days, respectively, elimination rate constant 0.0039 and 0.0036 hrs-1, time to reach steady state 5 to 8 weeks, maximal and minimal steady state concentration 85 and 66 mg/kg and 66 and 52 mg/kg, respectively. The concentration of white spirit in fat found each afternoon correlated significantly with the total dose. The concentration of white spirit/kg fat correlated positively with serum triglyceride and inversely with the percentage body fat (not significantly). The concentration of white spirit in the brain at steady state was estimated to maximum 11 mg/kg, while the half-life in the brain was estimated to maximum 18-19 hours. Minor differences occurred in the spectrometrical pattern produced by the in vivo biopsy evaporate as compared to in vitro specimens and white spirit vapours per se, thus indicating that the white spirit was slightly biotransformed or that the approximately 200 constituents of white spirit were absorbed differently. Thus, during exposure at the threshold limit value level, white spirit is accumulated in depot fat over weekends and in brain over working days. However, white spirit is almost eliminated from the brain during weekends.

Adipose Tissue↗
PubMed1984

Modulation of basal and LRH-stimulated gonadotrophin secretion by histamine in normal men.

The effects of histamine (HA) and of HA in combination with H1- and H2-receptor antagonists on basal and LRH-receptor antagonists on basal and LRH-stimulated LH and FSH secretion were investigated in 10 normal men. HA enhanced the LH response to LRH (p less than 0.05), but had no effect on basal LH secretion. The enhancement of LRH-stimulated LH secretion was not observed when either an H1- (mepyramine) or an H2- (cimetidine) receptor antagonist was administered concomitantly with HA. Cimetidine administered alone had no effect on basal or LRH-stimulated LH secretion. HA had no effect on basal or LRH-stimulated FSH secretion. We conclude that the effect of HA on LRH-stimulated LH secretion is mediated through a combined stimulation of H1- and H2-receptors.

Animals↗
PubMed1984

Primary malignant fibrous histiocytoma of the lung. A case report.

A case of malignant fibrous histiocytoma of the lung is presented and the literature concerning this rare tumour is reviewed. The advisability of postoperative chemotherapy in the cases remains to be clarified and further data are required to establish the optimum management.

Aged↗
PubMed1983

The effect of histamine stimulation and H2 -receptor inhibition on the pituitary prolactin and ACTH release and on cortisol secretion in human males.

The effects of histamine (HA) on prolactin (PRL), ACTH, and cortisol secretion in human males were investigated. Specific H2 -receptor blockade caused an immediate and significant PRL release, while specific H2 -receptor stimulation (HA and mepyramine) was without effect on PRL secretion. HA significantly stimulated both ACTH and cortisol secretion, and this stimulation was probably mediated through H2 -receptors, H2 -receptor blockade caused a late, but significant ACTH release. This release was not accompanied by a release of cortisol, and might therefore be due to a spontaneous oscillation in ACTH secretion. The results support the theory that HA acts as a modulator of human ACTH secretion. A similar effect on PRL secretion as postulated by others could not be confirmed in this study.

Adrenocorticotropic Hormone↗
PubMed1983

Joint involvement in psoriasis: scintigraphic, radiologic and clinical findings.

The results of a double-blind prospective study on patients with uncomplicated psoriasis (Ps), psoriasis with arthritis (PA) and a control group (C) are reported. The three groups were matched for age and sex. In the Ps and C groups no significant difference of the radiographic and scintigraphic results was found. The PA group showed significantly more scintigraphic accumulations compared to the two other groups, but no connection between scintigraphy and joint symptoms was found. The patients in the Ps and PA groups were treated with zinc sulfate per os for 8 weeks with no change in the radiographic findings. The PA group showed less and the Ps group more scintigraphic lesions after treatment. During treatment a small but significant decrease in hemoglobin, serum iron and gamma globulin was shown.

Adolescent↗
PubMed1983

alpha-Amylase determination using maltopentaose as substrate.

The rationale of choosing a NADP-coupled continuous method, with the substrate maltopentaose, as a method for the determination of alpha-amylase (EC 3.2.1.1) activity is investigated. The method presented is investigated with respect to all reaction parameters, including possible influence of protein, and shows zero order reaction kinetics after a 5-6 minute lag phase. The blank reaction from maltopentaose substrate is constant and is 13% of the upper limit of the reference interval for serum. The course of the blank reaction can be used to check that the maltopentaose is of adequate purity for use in the assay. Km for maltopentaose is 0.48 mmol/l. There is no interference from endogenous glucose when the total NADP turnover is less than 0.25 mmol/l. Data for sensitivity, linearity and long term precision over an eighteen month period are given, together with reference intervals for serum and for urine. The method is recommended for consideration as a reference method.

Amylases↗
PubMed1983

Perforation and rupture of the esophagus.

A series of 57 esophageal perforations from the period 1963-1982 is reported. They comprised 42 iatrogenic, instrumental perforations and 15 non-iatrogenic, mainly spontaneous and postemetic ruptures. The clinical manifestations were mostly pain, fever, subcutaneous and mediastinal emphysema, pleural effusion and pneumothorax. Esophageal leak was demonstrated in 73% of contrast studies. The overall mortality rate was 25%. It was 21% in cases with primary suture closure and 50% when treatment consisted of drainage. The mortality rate was 19% when treatment was begun within 24 hours and 35% when there was longer delay. Other factors influencing the mortality rate seemed to be type and location of the perforation and age of the patient. Early surgical intervention is advocated for perforation or rupture of the intrathoracic esophagus. Data in the literature and our own findings indicate that also in cervical esophageal perforations early surgical repair is justifiable.

Adult↗
PubMed1983

Comparison of P388D1 mouse macrophage cell line and human monocytes for assay of dengue-2 infection-enhancing antibodies.

Tissue culture-adapted dengue 2 virus (DEN 2), strain 16681, exhibits antibody-dependent enhancement of infection (ADE) in P388D1 cells, a mouse macrophage-like cell line. ADE is dependent upon maintaining DEN 2 multiplicity of infection at between 0.1 and 0.001, and can be simply measured in multi-well plastic plates. The assay uses either trypsinized or non-trypsinized P388D1 cells at 5 x 10(5) cells per ml, an appropriate dilution of DEN 2 virus, and a source of antibody, and is most conveniently performed without further washing of stationary cultures, which are incubated in 5% CO2. Trypsinization of P388D1 cells prior to the addition of virus-serum mixtures reduced infection in control cultures thus increasing ADE. When cells were washed after incubation of virus-serum mixtures for 1 hour, a paradoxical increase of infection in cultures exposed to virus plus normal serum was noted, which reduced the sensitivity of the ADE assay. Using human cord blood sera, ADE titers measured in human monocytes and P388D1 cells were closely similar. This convenient and economical assay will facilitate large scale biological and epidemiological studies of dengue virus enhancing antibodies.

Animals↗