Biomedical subjects

B W Karlsson

Publications and source records attributed to B W Karlsson.

At least 37 records · Page 2Linked to original sources

PubMed1990

Development of exocrine pancreas function in chronically cannulated pigs during 1-13 weeks of postnatal life.

The development of exocrine pancreas function was studied in Swedish Landrace pigs surgically fitted with a chronic pancreatic duct catheter and a duodenal re-entrant cannula. The juice secretion and output of total protein and trypsin activity were followed before (basal secretion) and after feeding (postprandial secretion) during the first 1-13 weeks of life. The results showed that throughout the suckling period, up to 4-5 weeks of age, the basal pancreas function remained low and the secretory response to feeding, i.e., nursing sow milk, was also low. After weaning, the pancreatic juice secretion as well as the output of protein and trypsin activity markedly increased with respect to both basal and postprandial levels. Furthermore, the enzyme composition of the pancreatic juice changed qualitatively during this period. During the first 2 weeks of life, the intravenous administration of cholecystokinin (CCK) and secretin did not stimulate exocrine function, but a significant effect was achieved from 3-4 weeks of age. These results showed that there was both an increase in exocrine pancreas function and a qualitative change in the hydrolytic enzyme pattern during porcine postnatal ontogeny, apparently correlated with the changes in diet around weaning. An increase in the response of the pancreas to hormonal stimulation was also observed during the suckling period.

Age Factors↗

PubMed1990

Permeability of the respiratory tract to different-sized macromolecules after intratracheal instillation in young and adult rats.

The markers, bovine IgG (BIgG, mol. wt = 150,000 Da) and bovine serum albumin (BSA, mol. wt = 67,000 Da) together with 1-deamino-cysteine-8-D-arginine vasopressin (dDAVP, mol. wt = 1067 Da), were intratracheally instilled into young and adult rats and their passages via the respiratory tract were assessed as immunoreactive marker levels in blood serum. In the adult rats (100-120 days old) the BSA serum levels peaked 16-24 h after instillation and with a calculated transferred amount (bioavailability) of 4.3 +/- 1.7 to 5.6 +/- 1.4% of the dose given (five resp. 50 mg kg-1 body wt). BIgG passed via the respiratory tract with a maximum at 16 h, and with a transferred amount of 1.5 +/- 0.3%, while dDAVP serum levels peaked at 1 h and with a transferred amount of 20 +/- 4%. For the 30-day-old rats, similar passage time curves were obtained as for the adult, but the transferred amount was lower for BIgG (0.7 +/- 0.3%), similar for BSA (4.1 +/- 1.1%) and higher for dDAVP (45 +/- 16%). The serum levels of BSA increased linearly with increasing dose instilled (2.5-200 mg kg-1 body wt), indicating a passive transepithelial transport route. The results show that macromolecules pass via the respiratory tract into the circulation of the rat in mainly intact forms and in high amounts, compared with passage via the GI tract. There appears to exist an inverse relationship between the molecular weights of instilled molecules and the transferred amount, a relationship affected by the development of the lung.

Aging↗

PubMed1990

Intestinal macromolecular transmission in underprivileged and unaffected newborn pigs: implication for survival of underprivileged pigs.

Passive immunisation of the newborn pig depends upon intestinal macromolecular transmission to the blood, which ceases within 18 to 36 hours after birth in fed pigs. Macromolecular transmission in newborn, unsuckled pigs was tested by gavage feeding bovine serum albumin and fluorescein isothiocyanate-labelled dextran (molecular weight 70 kDa) together with sow colostrum. Serum levels measured four hours after feeding showed that underweight pigs under 1.0 kg, both apparently normal and weak, had a greater capacity for transmission than did apparently normal pigs over 1.0 kg (unaffected). Weak pigs 1.0 kg, or more, had a transmission equivalent to that of unaffected pigs, indicating that they may be otherwise normal animals affected by birth. Splayleg pigs and their clinically unaffected littermates also showed a greater capacity for transmission than unaffected pigs; splayleg apparently involves the entire litter, although the expression of the syndrome varies. The capacity for transmission in the unaffected pig increased with litter size and decreased with an increase in weight and age after birth. In addition, it was shown that transmission was greater in pigs with higher glucose, insulin and alpha-fetoprotein concentrations and lower haemoglobin, cortisol and alpha 2-macroglobulin f concentrations at birth. It was concluded that immature pigs have a greater capacity for intestinal macromolecular transmission at birth than unaffected pigs over 1.0 kg. Since the capacity for macromolecular transmission decreases with age, the probability of their survival depends very much on the husbandry practices in the herd.

Animals↗

PubMed1988

Decreased passage of the nonapeptide dDAVP over the intestinal epithelium during development in the young rat.

The nonapeptide 1-deamino-cysteine-8-D-arginine vasopressin (dDAVP) was gavage-fed together with cow's milk whey protein to young, developing rats. The transepithelial passage of dDAVP in the gastrointestinal (GI) tract was assessed by a specific RIA as immunoreactive levels in blood serum extracts and as urinary excretion of dDAVP 0.5-8 h after feeding. In 14-day-old rats the passage of dDAVP was higher than in 30-day-old rats, since the 14-day-old rats had significantly higher serum levels (5-10 times) 0.5-2 h after feeding and a urinary excretion approaching 0.15% of the administered amount after 8 h. In the 30-day-old rats urinary excretion increased up to 0.05% after 2 h and then levelled off. It was also clear that 30-day-old rats had a slower transfer to and faster elimination from serum than 14-day-old rats. dDAVP appeared to be passed over the GI tract mucosa independently of intestinal proteolysis since feeding it to 30-day-old rats together with the proteinase inhibitors, soya-bean trypsin inhibitor and pepstatin did not influence the serum or urinary levels. Thus, dDAVP was taken up from the GI tract into the blood circulation and excreted in the urine of young rats. The decrease in the passage of dDAVP found around weaning appears to be related to developmental processes affecting the permeability of the intestinal epithelium rather than intestinal proteolysis.

Animals↗

PubMed1988

The uptake of fluorescein-conjugated dextran 70,000 by the small intestinal epithelium of the young rat and pig in relation to macromolecular transmission into the blood.

The macromolecular transmission from the intestinal lumen into the circulation, and its cessation (intestinal closure), were investigated in young rats and pigs in relation to the enterocytes ability to internalize macromolecules. After gavage feeding of FITC-labelled dextran 70,000 (FITC-dextran) and bovine serum albumin (BSA), the uptake of FITC-dextran into the enterocytes was examined by fluorescence microscopy, and the intestinal transmission of both markers was estimated from their blood serum concentrations. In both preclosure rats (14-days old) and piglets (newborn, unsuckled), high serum concentrations of the markers were correlated with the presence of highly fluorescent enterocytes. Although the transmission of the markers to the blood had ceased in postclosure suckling pigs (24-h old), the enterocytes showed a high fluorescence, indicating that the cellular uptake of FITC-dextran was still high. In the 6-days old piglets, only the distal part of the intestine showed uptake of FITC-dextran. In postclosure rats (21- and 30-days old) and in pigs 4-8 weeks old, no fluorescence in the enterocytes and only trace amounts of markers in the serum could be detected. These results reflect differences in the closure process between the species. In the rat, closure is likely to be due to a decrease in the endocytotic activity of the enterocytes, whereas closure in the pig is related to a cessation of the passage of internalized material into the blood (transcytosis).

Animals↗

PubMed1987

Identification and characterization of eight porcine pancreatic proteinases, carboxypeptidase A and amylase after electrophoretic separation using specific substrates.

Porcine pancreatic hydrolases in juice and homogenate surveyed by electrophoretic separation in agarose gel, at pH 8.6 and subsequently characterized using substrates of various specificity, either directly in the gel or after transfer to nitrocellulose (enzymoblotting) showed: Anodal and cathodal trypsin with Bz-Arg-pNA. Chymotrypsin A, B, and C with similar, but not identical, activities to Suc-Ala-Ala-Pro-Phe-pNA, Bz-Tyr-pNA, Suc-Phe-pNA and Ac-Phe-beta NE and with differences in their molecular weights and electrophoretical charges. Elastase I and protease E with Suc-(Ala)3-pNA and MeO-Suc-Ala-Ala-Pro-Val-pNA and elastase I also with elastin. Elastase II with the chymotrypsin substrates and with elastin. Carboxypeptidase A with CN-Phe. Amylase with blue starch polymer.

Amino Acid Sequence↗

PubMed1987

Development of porcine pancreatic hydrolases and their isoenzymes from the fetal period to adulthood.

The appearance and activity of various porcine pancreatic hydrolases were studied during fetal and postnatal development. Quantitatively, the enzyme activities in activated pancreas homogenates were low but increased during the second half of the fetal period, using the substrates Bz-Arg-pNA for measuring anodal and cathodal trypsin, Suc-Phe-pNA (chymotrypsin A and C, and elastase II) and Suc-(Ala)3-pNA (elastase I and protease E). Postnatally, after an initial decrease during the first week, the enzyme activities increased markedly, especially from 10-14 weeks to 6 months. The individual hydrolases were identified after electrophoretic separation in agarose gel and staining with various substrates either directly in the gel or after transfer to nitrocellulose membranes (enzymoblotting). During the fetal period, chymotrypsin A and B, elastase II, carboxypeptidase A, and amylase appeared at approximately 65 days and anodal trypsin, at approximately 76 days. After birth, new proteinases appeared after the first week including chymotrypsin C, cathodal trypsin, and protease E, whereas elastase I was found from 5 weeks after birth. Concomitantly, unidentified "fetal proteinase(s)" with caseinolytic, Ac-Phe-beta NE and CBZ-Ala-beta NE activities began to diminish and disappeared 10-14 weeks after birth. This study showed a marked increase in the overall pancreatic enzyme activities, as well as an age-dependent expression of the variety of pancreatic hydrolases during porcine ontogeny.

Aging↗

PubMed1987

Intestinal macromolecular transmission in the young rat: influence of protease inhibitors during development.

Intestinal macromolecular transmission in young rats of 10, 14, 18, 22 and 30 days of age was measured as the blood serum levels of markers 6 h after oral feeding of a solution containing bovine IgG (BIgG), bovine serum albumin (BSA) and fluorescein-isothiocyanate-labeled dextran 70,000 (FITC-D), either alone (controls) or with soybean trypsin inhibitor (SBTI) or swine colostrum trypsin inhibitor (SCTI). In the 10- and 14-day-old rats, transmission of all three macromolecular markers was high, with a preference for IgG. Transmission was greatly reduced by the age of 18 days and totally arrested for the protein markers at 22 days, with a low transmission of FITC-D remaining at 30 days of age. Addition of either of the two protease inhibitors significantly elevated the transmission of the protein markers in the rats aged 10, 14 and 18 days, while the transmission of the protease-independent marker FITC-D was unaffected. From 14 days of age, the rats have a functioning intestinal proteolysis, since only small amounts of marker proteins were left in the gut lumen 6 h after feeding, and since the addition of protease inhibitors resulted in increased amounts of undegraded proteins intraluminally. The results indicate that the increase of intraluminal proteolytic activity during development and the presence of protease inhibitors in the food are of importance for the intestinal transmission of undegraded proteins in the young rat. The Fc receptor for IgG in the enterocyte is not sufficient to maintain an optimal transmission of IgG, since the intraluminal proteolytic activity also appears to be of importance.

Animals↗

PubMed1986

Enzymoblotting: a method for localizing proteinases and their zymogens using para-nitroanilide substrates after agarose gel electrophoresis and transfer to nitrocellulose.

A method--enzymoblotting--was developed for localizing various enzymes after electrophoretic separation, transfer to nitrocellulose, and incubation with specific substrates. As an application, the proteinases porcine trypsin (EC 3.4.21.4), bovine chymotrypsin (EC 3.4.21.1), porcine elastase (EC 3.4.22.11), and their zymogen forms from porcine pancreas homogenate were analyzed utilizing specific p-nitroanilide substrates. After agarose gel electrophoresis, transfer of the separated proteinases to a nitrocellulose membrane was performed by capillary diffusion for 30 min. After air-drying of the nitrocellulose membrane, it was incubated in the appropriate substrate solution for 60 min. N-alpha-Benzoyl-DL-arginine-para-nitroanilide HCl was used as a substrate for trypsin, N-benzoyl-L-tyrosine-para-nitroanilide and succinyl-L-phenylalanine-para-nitroanilide for chymotrypsin, and N-succinyl-L-alanyl-L-alanyl-L-alanine-para-nitroanilide for elastase. p-Nitroaniline, the product thus obtained, was diazotized with N-(1-naphthyl)ethylenediamine to a red azo dye, visible at the site of the proteinases on the nitrocellulose membrane. The results could be preserved at -18 degrees C. Zymogen forms of the pancreas proteinases were detected in a similar manner. They were converted to active proteinases in situ on the nitrocellulose membrane after preincubating the nitrocellulose membrane in the activation enzymes enteropeptidase or trypsin.

Aniline Compounds↗

PubMed1986

Proteinase inhibitors in the gastrointestinal tract, pancreas and liver during fetal and postnatal development of the pig.

The occurrence and types of proteinase inhibitors were studied in the digestive system during the fetal and postnatal development of the pig. The protein concentration, the total trypsin-inhibiting capacity and the levels of the individual proteinase inhibitors, alpha 2-macroglobulin f (alpha 2Mf), alpha 2-macroglobulin s (alpha 2Ms), alpha 1-protease inhibitor (alpha 1PI) and alpha 2-antitrypsin (alpha 2AT) quantified by using electroimmunoassay, were assayed in stomach and intestinal contents, in homogenates of the stomach and intestinal mucosa, and in the pancreas and liver. The results showed that during porcine ontogeny high amounts of proteinase inhibitors are present in the digestive system. During the fetal period, the most outstanding characteristic was the high levels of alpha 1PI and alpha 2AT, in contrast to the low levels of the alpha 2-macroglobulins. Furthermore, the trypsin-inhibiting capacity and the levels of alpha 1PI and alpha 2AT showed in most cases a statistically significant decrease during the fetal period (12-36 cm crown-to-rump length). In the neonatal period, 0-96 h after birth, the levels of the individual inhibitors were rather constant, but a significant decrease to low levels of both trypsin inhibition and the individual inhibitors was observed in the adult pig. Trypsin activity was found in approximately half of the pancreas homogenates from the late fetal period and in newborn pigs before they began to suckle. The physiological function of the proteinase inhibitors observed in the digestive system during porcine ontogeny is probably to protect against precocious proteolytic degradation by the formation of inactive enzyme/inhibitor complexes.

Animals↗

PubMed1985

Intestinal transmission of macromolecules (BSA and FITC-dextran) in the neonatal pig: enhancing effect of colostrum, proteins and proteinase inhibitors.

The effects of colostrum and constituents/factors in colostrum which may influence intestinal macromolecular transmission in the newborn preclosure pig were investigated. Unsuckled piglets were given, by use of a stomach tube, bovine serum albumin (BSA) and fluorescein-isothiocyanate (FITC)-labelled dextran 70,000 (FITC-D) as markers together with colostrum or the factors under study. The serum levels of BSA and FITC-D 4 h after feeding were then determined as a measure of the transfer. It was found that the two colostrums tested, bovine and especially porcine, markedly enhanced the transmission of both BSA and FITC-D. Furthermore, increasing amounts of the model proteins, BSA and bovine IgG (50-200 mg/ml), significantly increased the transfer of FITC-D, whereas unlabelled dextran 70,000 given in similar amounts did not. Proteinase inhibitors obtained from sow colostrum or soy bean also enhanced the transmission of both BSA and FITC-D while the inactive inhibitors, given as trypsin-inhibitor complexes, had no effect. On the other hand, addition of a proteinase, porcine trypsin, significantly decreased the transmission of FITC-D. These findings indicate that the intestinal transmission of macromolecules in the preclosure piglet is governed by the amount of protein available in the intestine. Therefore, feeding colostrum with a high protein content and proteinase inhibitors is likely to favour efficient intestinal transmission, although other colostrum factors may also be of importance.

Animals↗

PubMed1984

The passage of orally fed proteins from mother to foetus in the rat.

Pregnant rats were orally fed with a mixture of bovine IgG, bovine albumin, ovalbumin and beta-lactoglobulin. Using immunoprecipitation methods, these proteins were detected in the maternal blood serum, urine and uterine fluids, and also in the foetal blood serum and the amniotic fluid. The results imply that a variety of dietary proteins, still immunoprecipitable, are able to cross the materno-foetal barriers to be detected in the foetal circulation, where they may influence the maturation of the immune system of the foetus.

Animals↗

PubMed1984

Intestinal transmission of macromolecules (BSA and FITC-labelled dextrans) in the neonatal pig. Influence of age of piglet and molecular weight of markers.

The intestinal transmission of two macromolecular markers, of similar molecular weight but different susceptibility to proteolytic digestion, was investigated in the neonatal pig. Piglets of varying age (0 h-7 days old) were given a mixture of bovine serum albumin (BSA) and fluorescein-isothiocyanate labelled dextran 70,000 (FITC-D 70) by stomach tube, and the serum concentrations were determined 2 h after feeding. A high correlation between the patterns of transmission were obtained for the two marker substances (r=0.91, n=39). Furthermore, a rapid decrease in the transmission of the markers was observed during the first day of life in suckled piglets, and intestinal macromolecular closure was well developed in the piglets after 18-36 h of life. These findings indicate that 'closure' is unrelated to changes in intestinal proteolytic activity. After closure, only small amounts of the markers were transmitted to the serum. During the first day of life, great individual differences in the transmission were found between piglets. As shown by feeding different-sized FITC-D (MW = 3,000-70,000 dalton) and unconjugated FITC (MW = 389 dalton), molecules having a molecular weight greater than 3,000 daltons were excluded upon macromolecular closure. On the other hand, smaller molecules like FITC were transmitted across the intestinal barriers independent of closure.

Aging↗

PubMed1983

Immuno-cross-reactivity between alpha-macroglobulins from pig, dog, rat and man including human pregnancy-associated alpha 2-glycoprotein.

The antigenic relationships between the alpha-macroglobulins in human blood plasma and in serum from pig, dog and rat were investigated using ordinary immunoelectrophoresis and line immunoelectrophoresis. The results imply that these alpha-macroglobulins are more or less antigenically related. This is true also for human pregnancy-associated alpha 2-glycoprotein which is the only alpha-macroglobulin without reported proteinase-inhibiting properties. Among the alpha-macroglobulins a reciprocal cross-reactivity was observed for eight pairs, indicating a close structural relationship.

Animals↗

PubMed1982

In vitro interaction of porcine serum and colostrum protease inhibitors with pancreatic trypsin, chymotrypsin and elastase.

The partition of 125I-labelled pancreatic trypsin, chymotrypsin and elastase between the inhibitors, alpha 2-macroglobulin f and s, alpha 1-protease inhibitor, alpha 2-antitrypsin, inter-alpha-trypsin inhibitor and the specific sow colostrum protease inhibitor, was studied in vitro by gradually increasing the concentration of these proteases in blood serum from adult and newborn pigs. As revealed by immunoelectrophoresis in combination with autoradiography, differences were noted in the abilities of the various protease inhibitors to interact with and to form complexes with the three proteases, resulting in changes in location, height and numbers of precipitates. Among the serum inhibitors, alpha 2-macroglobulins showed the highest relative affinity to all three proteases, while alpha 1-protease inhibitor showed a high relative affinity only for chymotrypsin. Serum alpha 2-antitrypsin complexed only with trypsin, with a low relative affinity. alpha 2-Antitrypsin also interacted with chymotrypsin and elastase, but without forming complexes. When complexes of sow colostrum protease inhibitor and trypsin were added to the serum from neonatal pigs, these complexes remained stable. The results obtained from these in vitro studies, indicating differences in the relative affinities of the inhibitors to the various proteases, give some information about the role of the inhibitors in vivo, both in adult and in neonatal pigs.

Animals↗

PubMed1982

Levels of serum protease inhibitors during fetal and postnatal development of the pig.

Using electroimmunoassay the levels of the individual protease inhibitors alpha-2-macroglobulin f, alpha-2-macroglobulin s, inter-alpha-trypsin inhibitor, alpha-1-protease inhibitor and alpha-2-antitrypsin were studied in the serum and the amniotic fluid during the fetal and postnatal development of the pig. High concentrations, far above the adult ones, of alpha-2-antitrypsin and especially alpha-1-protease inhibitor, were observed in serum during the fetal period, contrary to the low levels of the alpha-macroglobulins. Thus, the development of these inhibitors in pigs differs markedly from the development in the human fetus. After birth, when the piglet had begun to suckle, the levels of all the inhibitors, except that of alpha-2-macroglobulin s, decreased. This can partly be explained by the dilution of the serum due to the increase in plasma volume and losses via the urine. The sharp increase of alpha-2-macroglobulin s during the first days after birth probably represented an extensive synthesis. All the inhibitors had attained their adult levels at about 35 days after birth. All the protease inhibitors studied, except for alpha-2-macroglobulin s, were found in the amniotic fluid, and reached the maximal levels at about 55-66 days of gestation. These inhibitors appeared to have fetal origin. The physiological significance of the protease inhibitors during fetal and neonatal development of the pig is discussed. it is suggested that the function of these inhibitors might be to protect the cells and tissues from proteolytic attack by the formation of inactive enzyme/inhibitors complexes.

Aging↗

PubMed1982

Proteolytic activity as a regulator of the transmission of orally fed proteins from the gut to the blood serum in the suckling rat.

14-day-old rats were orally fed with porcine colostrum or serum having a low or high activity of protease inhibitors (i.e., sow colostrum trypsin-chymotrypsin inhibitor or soybean trypsin inhibitor). The uptake of undigested porcine albumin and IgG to the blood serum of these rats was studied 4 h after feeding. The effect of the exclusion of proteases to the intestinal lumen by means of pancreatic duct ligation prior to feeding was also studied. The results from these feeding experiments in the presence of protease inhibitors or in the absence of pancreatic proteases agreed well. It was concluded that for the sucking rat the intraluminal proteolytic activity in the gastrointestinal tract is a regulator for nonselective protein uptake, as represented by albumin, while the selective absorption of IgG was unaffected.

Animal Population Groups↗

PubMed1982

Lipoprotein and lipid profiles in the blood serum of the fetal, neonatal and adult pig.

As revealed by agarose gel electrophoresis and immunoassay, followed by staining with Sudan black, lipoproteins occur in the alpha-, pre-beta- and beta-regions of the serum of fetal, newborn, neonatal, juvenile and adult pigs. These lipoproteins undergo characteristic quantitative changes during development. After the onset of colostrum ingestion, a lipid-stainable zone appeared in the gamma-region of piglet's serum and sow colostrum/milk. The levels of total serum lipids, cholesterol, high and low density lipoproteins were low at birth in comparison to those of the adult pig, but increased to higher levels after the onset of colostrum and milk ingestion. After 3-8 weeks, the total lipids, cholesterol and low density lipoprotein values had decreased to adult level but the high density lipoprotein values remained high in comparison to the adult pig. It is discussed that the changes found in lipoprotein and lipid patterns in serum of the developing pig reflect changes in cellular metabolism and nutritional needs of the organism. It is suggested that the perinatal pig might be a useful model for studying the development of atherogenic diseases in man.

Aging↗