Search PubMed⌕ Search

Biomedical subjects

L A Lindberg

Publications and source records attributed to L A Lindberg.

At least 37 records · Page 2Linked to original sources
PubMed1988

Expression of the human transferrin receptor in subrenal capsule assay in the mouse.

The expression of a cell proliferation marker, the human transferrin receptor, was studied in ten human gastrointestinal tumors prior to and after implantation under the renal capsule in the mouse (1-6 days). These data were compared to the increase in tumor size in situ, and to the infiltration of inflammatory cells. All tumors studied expressed the transferrin receptor prior to implantation. Forty of 47 implants expressed the receptor, the strongest expression occurring on day 4, accompanied by a reorganization of tumor tissue to a morphology similar to that before implantation. On days 5 and 6 the expression of the transferrin receptor declined. Implants showed maximal increase in size on days 1 and 2, decreased in size on days 3 and 4, and increased again on days 5 and 6. The increase in the size of the implants on days 5 and 6 was accompanied by considerable infiltration of inflammatory cells, and was probably mostly a result of invading host cells and inflammation. If size alone is used as a criterion for tumor proliferation in this subrenal capsule assay, day 4 seems to be the most appropriate for evaluation. This is supported by a strong expression of a proliferation marker, the human transferrin receptor, during this time.

Animals↗
PubMed1988

Use of monoclonal antibodies to serotype-specific antigens of Haemophilus pleuropneumoniae serotype 2 in passive immunization.

The prophylactic value of mouse monoclonal antibodies to the pig pathogen Haemophilus pleuropneumoniae was studied. Approximately 250 mg of purified mouse monoclonal antibody specific to capsular antigens of H pleuropneumoniae serotype 2 was given IV to five 9-week-old pigs. Five additional pigs from the same litter served as controls. On the following day, all pigs were given a lethal dose (5 x 10(9)) of H pleuropneumoniae serotype 2 into the trachea. Four controls and 1 pig that was given antibodies died within 24 hours. The surviving 5 pigs developed typical signs of pleuropneumonia. After 6 days, the pigs were euthanatized and their respiratory tracts were examined for pathologic changes. All 5 pigs had pathologic changes, but they were less severe in the 4 pigs that had been given antibodies, compared with those in the control pig.

Animals↗
PubMed1986

Reversible inhibition of flagella formation after specific inhibition of spermidine synthesis by dicyclohexylamine in Pseudomonas aeruginosa.

Dicyclohexylamine, which is an inhibitor of bacterial and mammalian spermidine synthase, greatly inhibited the synthesis of spermidine in Pseudomonas aeruginosa. The depletion of spermidine caused by dicyclohexylamine was accompanied by an inhibition of growth of bacteria. This inhibition was reversed by addition of 50 microM spermidine (but not putrescine or spermine) to growth medium. When its growth was inhibited Ps. aeruginosa also lost its motility. Electron microscopy showed a loss of flagella in spermidine-deficient bacteria: after 24 h 70% 85% of bacteria grown in the presence of dicyclohexylamine did not have flagella, whereas bacteria grown in the presence of dicyclohexylamine and spermidine had flagella. The loss of flagella was reversible, since after the inhibition of spermidine synthesis for 24 h, addition of 50 microM spermidine (but not putrescine or spermine) to the growth medium was able to restore the bacterial motility almost completely after a further 12 h growth period.

Cell Movement↗
PubMed1986

Structure and occurrence of perisinusoidal stellate cells in the liver of lactating dairy cows.

The structure and occurrence of liver stellate cells were studied in healthy, mildly and severely ketotic lactating dairy cows. In addition, the stellate cells in five clinically healthy lactating cows, each sampled at five different occasions after parturition, were studied. Liver samples were obtained by percutaneous needle biopsy, immediately fixed in 3% glutaraldehyde and processed for light and electron microscopy. The volume fractions of stellate cells and hepatocytic fat were estimated. Bovine stellate cells contained one, often large lipid droplet, not surrounded by a membrane. The cells had a well-developed Golgi apparatus and rough endoplasmic reticulum. Morphological indications for collagen synthesis by the cells were found. The results also suggest that a direct exchange of material between hepatocytes and stellate cells is possible. The volume fraction of stellate cells was decreased and the fraction of hepatocytic fat increased in severely ketotic cows as compared to the other groups. A negative correlation between the volume fractions of hepatocytic fat and stellate cells was significant. Hepatocytic fat decreased significantly after parturition, but an increase in the volume fraction of stellate cells was not significant.

Animals↗
PubMed1986

Hepatic morphology and effects of intravenous injection of sodium propionate on plasma propionate and glucose in fed and fasted dairy cattle.

Sodium propionate (3 mmol/kg) was injected IV into 8 nonlactating dairy cows before and after 6 days (144 hours) of fasting. During fasting, long-chain fatty acids in plasma increased from 0.30 +/- 0.05 (SE) mM to 1.09 +/- 0.15 mM (P less than 0.05). Liver fat increased from 0.5 +/- 0.3% to 9.3 +/- 1.7% (P less than 0.05). Half-life of injected sodium propionate increased significantly (P less than 0.05) from 7.6 +/- 0.5 minutes to 10.1 +/- 1.0 minutes during fasting. Sulfobromophthalein half-life did not change significantly (3.8 +/- 0.79 minutes to 5.3 +/- 1.3 minutes). Increases in plasma glucose concentrations after propionate loading were significantly less during fasting than during feeding. Thus, the change in glucose concentration served as an indicator of hepatic conversion of propionate to glucose. Increases in glucose concentration of less than 2 mM at 30 minutes after propionate loading indicated that liver function was altered in nonlactating dairy cows.

Animals↗
PubMed1985

Ultrastructural changes of the liver in spontaneously ketotic cows.

The ultrastructure of the liver in normal, mildly ketotic and severely ketotic cows was studied using stereological methods. In the liver of severely ketotic cows there is: (1) a significant increase in the volume fraction of hepatocytes and a decrease in the volume fraction of sinusoids, and (2) an increase in the volume fraction of lipid and smooth endoplasmic reticulum and a decrease in the volume fraction of glycogen and Golgi in parenchyma. A decrease in the profile density of mitochondria per 1 mm2 field and an increase of the volume occupied by mitochondria were not significant nor was the decrease in the volume density of rough endoplasmic reticulum. The degree and duration of negative energy balance obviously affect the morphological changes of the fatty liver. However, additional work is needed to determine the significance of ultrastructural changes in liver function.

Acidosis↗
PubMed1985

Propionate loading test for liver function during experimental liver necrosis in sheep.

The first objective of this work was to study the conversion of propionate to glucose by liver of the sheep during experimentally induced liver necrosis. An additional objective was to determine the most appropriate sampling time after a propionate load has been given to use glucose concentration as an aid in the diagnosis of disturbed liver function. Sodium propionate (3 mmol/kg) was injected IV into 6 healthy sheep before and after they were given carbon tetrachloride (20% CCl4 in mineral oil; 0.25 ml of CCl4/kg, orally). To differentiate the effects of liver necrosis from the effects of decrease in food intake after CCl4 administration, 5 sheep which were fasted for 2 days, but not given CCl4, were studied. Microscopically, liver necrosis was observed, as well as an increase of fatty infiltration in nonnecrotic liver tissue. After sheep were given CCl4, the plasma liver-specific enzyme activities (namely, those of iditol dehydrogenase and gamma-glutamyl-transferase) were elevated. Microscopic and enzymatic changes were not observed in fasted animals. Serum sulfobromophthalein (BSP) half-life (t1/2) was markedly increased in the sheep given CCl4 treatment (t1/2 = 22.8 +/- 11 minutes) when compared with the t1/2 before treatment (t1/2 = 2.5 +/- 0.2 minutes). The BSP t1/2 did not differ between fed and fasted sheep. The t1/2 of the IV propionate load increased significantly, from 6.9 +/- 0.4 minutes in the control sheep to 12.8 +/- 2 minutes in the CCl4-treated sheep, whereas an insignificant increase was seen after fasting (6.8 +/- 1 minutes to 8.3 +/- 1 minutes.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1983

Fatty infiltration of liver in spontaneously ketotic dairy cows.

The purpose of this study was to ascertain 1) fatty infiltration of the liver in spontaneously ketotic cows and 2) the most appropriate blood components to aid diagnosis of ketotic fatty liver. Liver biopsies and blood samples were obtained under field conditions. Cows were divided into three groups (healthy, mildly ketotic, and severely ketotic) by their blood ketone body concentrations. Severely ketotic cows had a greater percent fat in the liver than healthy cows. The mildly ketotic group fell between the other two groups and was significantly different from only the severely ketotic group. There was a positive correlation between fatty infiltration and blood ketone body concentrations but a negative correlation with glucose concentrations. Liver-specific enzymes were positively correlated with fatty infiltration. Only ornithine carbamoyltransferase and iditol (sorbitol) dehydrogenase could be used to separate healthy cows from those with severe ketosis. The best equation to explain the variation of percent fat in liver included concentration of beta-hydroxybutyrate (BHB) and logarithm of ornithine carbamoyltransferase concentration (Log-OCT): % Fat = -6.15 + 2.39 (BHB) + 11.7 (LogOCT) Although this equation explained 39.5% of the variation, it could not be used to predict reliably percent fat in the liver. Liver biopsy seems still to be the only reliable method of measuring of fatty infiltration in the liver.

3-Hydroxybutyric Acid↗