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Biomedical subjects

T Larsen

Publications and source records attributed to T Larsen.

At least 127 records · Page 7Linked to original sources
PubMed1988

Sulfur-containing macromolecules in cultured monocyte-like cells.

The monocytic cell line U-937 was cultured in vitro in the absence or presence of phorbol myristate acetate, and agent known to induce differentiation of these cells along the monocyte/macrophage lineage. The cells were fixed, prepared for, and subjected to transmission scanning electron microscopy. The intracellular structures of the cells were compared with those of mastocytoma cells. The latter cell type, known to produce heparin, was shown to contain numerous electron dense granules; by X-ray micro-analyses shown to contain significant amounts of sulfur. In contrast, neither control nor PMA-treated U-937 cells contained such granules. Both control and PMA-treated U-937 cells were pulsed with 35S-sulfate for 60 min and chased. The amount of 35S-proteoglycan in the medium of both cell cultures was found to increase in a time-dependent manner, suggesting that these products are destined for release and not intracellular storage under in vitro conditions.

Cell Line↗
PubMed1988

EEG in the differential diagnosis between Alzheimer's disease and vascular dementia.

Demented patients with Alzheimer's disease (AD) (n = 67), multi-infarct dementia (MID) (n = 77) and probable vascular dementia (PVD) (n = 45) were studied with electroencephalography (EEG). All patients underwent a routine EEG examination and quantitative EEG was recorded from 14 patients with AD, 20 with MID, and 12 with PVD. The patient groups did not differ in regard to sex, age, education, or degree of dementia. Diffuse abnormality of EEG increased in AD, while driving response to photic stimulation and the mean frequency of background activity decreased in all groups with increasing degree of dementia. In quantitative EEG, the percentage of alpha power decreased and those of theta and delta power increased relative to the degree of dementia. Focal abnormalities, and irritative (spikes and/or sharp waves) and slow wave paroxysms were more common in MID than in AD. Patients with different types of dementia did not differ significantly in regard to diffuse abnormality, occurrence of driving response, mean background frequency, or parameters of quantitative EEG. The mean frequency of background activity and the degree of diffuse abnormality correlated with central and cortical atrophy, white matter low attenuation seen on computed tomography, and with neuropsychological findings.

Adult↗
PubMed1988

Effect of cooling on the intracellular concentrations of Na+, K+ and Cl- in cultured human endothelial cells.

Cooling is accepted as a practical way of lowering cell metabolism in vein grafts during coronary by-pass surgery. We have previously shown that low temperature causes endothelial cells to become detached, both in in vitro and in vein graft. In this study we have looked at the effect of cold on the concentrations of intra- and extracellular electrolytes. Human endothelial cells were grown on titanium grids for electron microscopy. The cells were incubated for 30 min at 37 degrees, 20 degrees, and 4 degrees C with cell culture medium containing human serum, and at 20 degrees and 4 degrees C with heparinized sodium acetate solution with serum, frequently used for flushing and distending vein grafts. Freeze-dried cells were then subjected to elemental X-ray microanalysis. The ambient fluid was analysed by flame photometry. At 20 degrees and 4 degrees C, intracellular concentration of sodium increased, and potassium decreased, compared with controls (37 degrees C). The changes in sodium concentrations were aggravated when cell culture medium was replaced by heparinized sodium acetate. The intracellular chloride concentration did not change when cells were stored in cold cell culture medium. The extracellular concentration of potassium increased with increasing incubation time at 4 degrees C. The connection between these findings and cell detachment is discussed.

Chlorides↗
PubMed1987

Intraabdominal granuloma reaction in rats after introduction of maize-starch powder.

A total of 32 Wistar rats were given 1, 10, 100 and 1000 mg glove powder (Biosorb) intraperitoneally for 4, 11, 18 or 25 days. Four control rats received physiological saline. Examination of the abdominal cavity displayed granulomatous inflammation which was clearly dose-dependent in the experimental animal, but not in the controls. A biphasic time-sequence of the granulomatous reaction was observed in those rats receiving 100 and 1000 mg Biosorb with a minimum at day 18. The mean size of the granules (8.1 microns) within the inflammatory tissue was almost identical with the size of powder granules found on the external surface of the gloves (8.8 microns). X-ray microanalysis demonstrated maize-starch additives of magnesium and aluminium. The study indicates a foreign body reaction to maize-starch. In addition, immunological factors may play a role later in the development of the disease.

Animals↗
PubMed1986

Phagocytosis of agarose beads by receptors for C3b (CR1) and iC3b (CR3) on human alveolar macrophages cultured on fibronectin in vitro. A scanning electron microscopic study.

We studied the phagocytosis of agarose beads by human alveolar macrophages in terms of the morphology, the receptors involved, and the cellular substrates (plastic or fibronectin) used. Beads coated with C3b (58%) and iC3b (42%) by treatment with serum, were ingested during 45 min by CR1 and CR3 on the macrophages. This ingestion was inhibited 80-90% by the presence of polyclonal F(ab')2 anti-C3 fragments. Since the phagocytosis of both C3b- and iC3b-coated beads was about threefold stronger than for C3b-coated beads (trypsinized serum-treated beads), the results indicate that the CR3 is more phagocytic than the CR1. The phagocytosis of initially complement uncoated beads, which are slowly opsonized with macrophage-produced C3b and iC3b in vitro, was also strongly inhibited (70-80%) by the presence of anti-human C3 F(ab')2 fragments. There was an increased phagocytosis (10-17%) of complement precoated beads by macrophages cultured on the fibronectin substrate versus the plastic substrate. The morphology and rapid phagocytosis of the complement precoated beads was demonstrated by SEM. The general impression was that membranous protrusions stretched towards the beads, which became increasingly enclosed by plasma membrane.

Adult↗
PubMed1986

Treatment of abscesses in the vulva. Conventional open treatment versus primary suture under antibiotic cover.

Seventy patients were treated for a subcutaneous abscess in the vulva. In 35 consecutive patients the abscess was treated conventionally with deroofing of the abscess and wet dressings. In the other 35 consecutive patients the abscess was treated by incision, curettage and primary suture under antibiotic cover with a single dose of clindamycin. In the conventionally treated group the median stay in hospital was 7 days and the median healing time 18 days. In the group treated by primary suture the median stay in hospital was 2 days and the median healing time 7 days (P less than 0.0001). Recurrence of abscess was observed in one patient in each group. No other complications were observed in either group. It is concluded that vulvar abscesses may be treated safely and advantageously by primary suture under antibiotic cover.

Abscess↗
PubMed1986

Pancreatic pseudocysts during first attack of acute pancreatitis.

One hundred and forty-eight patients admitted with their first episode of acute pancreatitis were examined by ultrasonography. During the acute attack 1 or more pseudocysts were found in 19 patients (13%), pancreatic abscess in 2, whereas 127 had a normal or swollen pancreas. Two small cysts resolved spontaneously, eight were cured after ultrasonically guided needle aspiration or catheter drainage, and cystogastrostomy was necessary in four cases. One patient refused treatment. Abscesses requiring surgical drainage developed in four of the patients with pseudocysts. The study showed that pseudocysts may appear as early as within 1 week of the first episode of acute pancreatitis. Some pseudocysts may resolve spontaneously, and ultrasonically guided aspiration or drainage may cure approximately half of the pseudocysts.

Acute Disease↗
PubMed1986

Injury to cultured endothelial cells by thrombin-stimulated platelets.

In vivo, stimulated platelets may injure the endothelium. We have used cultured endothelial cells to assess endothelial cell damage caused by platelet stimulation with thrombin. Endothelial cells were cultured from umbilical veins and semiconfluent cultures were labeled with Na2 51CrO4. Twenty four hours later washed human platelets (final concentration 200,000 platelets/microliters) and thrombin (final concentration 4 units/ml) were added to the medium and the culture dish was shaken for 15 minutes. The percentage of cells detached from the culture dish and the percentage of 51Cr lost from the endothelial cells into the ambient fluid during the shaking were determined and used as indicators of cell injury. Increased percentages of loosened cells and 51Cr in the ambient fluid were observed with platelet suspension and thrombin compared to controls with neither platelet suspension nor thrombin and controls with either platelet suspension or thrombin. The platelet-free supernatant obtained after reaction of the platelets with thrombin also increased the percentage of loosened cells, but it did not increase the percentage of 51Cr in the ambient fluid to a significant degree. Thrombin alone caused a moderate loss of 51Cr, but no increased loosening of cells. Treatment of the platelets with acetylsalicylic acid prior to the experiment depressed the detachment effect of thrombin-stimulated platelets, but did not alter the effect on the release of 51Cr into the ambient fluid. Scanning and transmission electron microscopy of cultured endothelial cells exposed to thrombin-stimulated platelets confirmed the presence of loosening and injury to the endothelial cells. Thus, platelet stimulation with thrombin had at least two effects on the cultured endothelial cells: a loosening effect caused by material released from the platelets; an injury effect which, in order to reach its maximum, required the presence of stimulated platelets.

Aspirin↗