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Biomedical subjects

K Andersson

Publications and source records attributed to K Andersson.

At least 181 records · Page 10Linked to original sources
PubMed1994

Short-term starvation alters the free amino acid content of the human intestinal mucosa.

1. The effects of short-term starvation and refeeding on the free amino acid concentrations of the intestinal mucosa were characterized in male subjects (n = 6), using endoscopically obtained biopsy specimens from the duodenum and from all four segments of the colon. 2. The alterations in the amino acid concentrations in response to short-term starvation were overall uniform in both duodenal and colonic mucosa as well as in plasma. Most amino acids decreased, whereas branched-chain amino acids increased. 3. In the colon, glutamic acid and glutamine decreased during the starvation period, whereas they remained unaltered in the duodenum. This was the major difference in response to short-term starvation between the amino acid concentrations in the intestinal mucosa of the duodenum and colon. 4. Refeeding for 3 days normalized the amino acid concentrations except for glutamic acid, asparagine and histidine, which remained low in the colon, and threonine, which showed an overshoot in both parts of the intestine. 5. The changes in mucosal amino acid concentrations seen in response to starvation and refeeding were uniform in the four segments of the colon. This suggests that sampling from the rectum/sigmoid colon will give representative values for the free amino acid concentrations of the entire large intestine.

Adult↗
PubMed1994

Stability of albumin, protein HC, immunoglobulin G, kappa- and lambda-chain immunoreactivity, orosomucoid and alpha 1-antitrypsin in urine stored at various conditions.

Urine samples from 10 randomly selected patients with advanced renal disease were each divided into six aliquots and a preservative solution containing benzamidinium chloride, EDTA, tris(hydroxymethyl)-aminomethane and azide was then added to three of the aliquots. Aliquots with and without additive were then stored at room temperature for up to 7 days, at 4 degrees C for up to 30 days and at -20 degrees C for up to 6 months. The concentrations of albumin, protein HC, IgG, orosomucoid and alpha 1-antitrypsin as well as the kappa- and lambda-chain immunoreactivities in the samples were determined by automated immunoturbidimetry or by single radial immunodiffusion after 1, 3, 7, 14, 30, 90 and 180 days of storage. All investigated proteins, except alpha 1-antitrypsin in native urine, were stable for 7 days in the samples stored at room temperature both in the presence and absence of additives. All investigated proteins, except alpha 1-antitrypsin in native urine, were stable for 30 days in the samples stored at 4 degrees C both in the presence and absence of additives. A more complex pattern was observed for the stability of the proteins in the frozen samples. The IgG level decreased rapidly in several samples stored without additives but not in samples stored with additives. The alpha 1-antitrypsin concentration decreased rapidly to about 50% of the initial value in several samples stored both with and without additives. The rate of the decrease for both the IgG and the alpha 1-antitrypsin level varied between samples and the main decrease for several samples was seemingly caused by the freezing and/or thawing per se and not by the storage period in between.

Albuminuria↗
PubMed1994

Exposure to low molecular polyamines during road paving.

Fatty amine wetting agents are used to increase adhesion in bitumen emulsions used in road paving, but commercial fatty amine products are contaminated with low molecular polyamines and alkanol polyamines which are released from the hot bitumen during paving. Polyamines and alkanol polyamines are known to cause eye and respiratory tract irritation and skin sensitization. The exposure of road pavers to ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, hydroxyethylethylenediamine, hydroxyethyldiethylenetriamine, monoethanolamine and diethanolamine was studied, since most of these compounds were found in the products used. Personal and static air sampling was performed during road paving. A highly sensitive measurement technique utilizing naphthylisothiocyanate-coated sorbents and filters was used. Exposure was found to be in the range < 0.02-0.5 mg m-3, as total concentration of low molecular polyamines and alkanol polyamines. Since the polyamines and alkanol polyamines in question are highly irritating they may contribute to the symptoms experienced by the road pavers.

Air Pollutants, Occupational↗
PubMed1994

ECL cells: biology and pathobiology.

During recent years, the so-called ECL cells of the acid-producing part of the stomach have attracted much attention, mainly due to the fact that mice and rats were found to develop gastric carcinoids (ECL cell tumors) following life-long treatment with blockers of acid secretion. These observations touched off concern about the safety of the long-term clinical use of such drugs. The ECL cells are the predominant endocrine cell population in the oxyntic mucosa. They produce histamine, chromogranin A/pancreastatin and an as yet unidentified peptide hormone. They respond to gastrin by the release of secretory products; more long-term responses include adaptation to the gastrin stimulus, hypertrophy and hyperplasia. Intravenous infusion of maximally effective doses of gastrin promptly reduced the number of cytoplasmic vesicles in the ECL cells and their content of histamine and pancreastatin. Despite the ongoing infusion of gastrin, the number of vesicles and the content of histamine and pancreastatin were back to normal 4-6 h after the start of the infusion. The histidine decarboxylase (HDC) activity and HDC mRNA level increased progressively until plateaus were reached after 6-8 h of gastrin infusion. The size of the ECL cells started to increase about 4 days after the start of a subcutaneous gastrin infusion (resulting in half-maximally effective serum gastrin concentrations). The ECL cell size reached maximum after about 2 weeks and then remained at this level.The number of cytoplasmic vesicles was increased; this effect seemed to reach a maximum after 1-2 weeks.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

A genetic study of estrus symptoms at puberty and their relationship to growth and leanness in gilts.

Puberty traits of 740 Yorkshire gilts from a selection experiment were analyzed. Heritabilities were estimated to be .32 for pubertal age, .23 for length of proestrus, .16 for length of standing estrus, .29 for ability to show standing reflex, and .24 for intensity of vulvar symptoms. Genetic correlations between length of proestrus, intensity of vulvar symptoms, and ability to show standing reflex were positive. There seemed to be a negative genetic correlation between percentage of lean and intensity of vulvar symptoms. There were negative genetic correlations between growth rate and length of standing estrus, and between growth rate and ability to show standing reflex.

Animals↗
PubMed1994

Updated and expanded Swedish cohort study on trichloroethylene and cancer risk.

There is limited evidence for mutagenicity and carcinogenicity of trichloroethylene (TRI) in experimental test systems. Whether TRI is a human carcinogen is unclear, however. This paper presents an update and extension of a previously reported cohort of workers exposed to TRI, in total 1670 persons. Among men (n = 1421), the overall standardized mortality ratio (SMR) and cancer morbidity ratio (SIR) were close to the expected, with SMR, 0.97; 95% confidence interval (CI), 0.86 to 1.10; and SIR, 0.96; 95% CI, 0.80 to 1.16, respectively. The cancer mortality was significantly lower than expected (SMR, 0.65; 95% CI, 0.47 to 0.89), whereas an increased mortality from circulatory disorders (cardiovascular, cerebrovascular) was of borderline significance (SMR, 1.17; 95% CI, 1.00 to 1.37). No significant increase of cancer of any specific site was observed, except for a doubled incidence of nonmelanocytic skin cancer without correlation with the exposure categories. In the small female subcohort (n = 249), a nonsignificant increase of cancer and circulatory deaths was observed (SMR, 1.53 and 2.02, respectively). For both genders, however, excess risks were largely confined to groups of workers with lower exposure levels or short duration of exposure or both. It is concluded that this study provides no evidence that TRI is a human carcinogen, ie, when the exposure is as low as for this study population.

Adult↗
PubMed1993

Further studies on the involvement of selenium in peroxisome proliferation in rat liver. Comparison of effects with clofibric acid and perfluorooctanoic acid and the pharmacokinetics of [14C]clofibrate.

Most effects of the peroxisome proliferator clofibrate on rat liver are marginal or absent in selenium (Se) deficiency. The purpose of the present study was to determine whether the uptake or distribution of clofibrate is altered by Se deficiency. Rats were fed a Se-adequate or -deficient diet for 10-11 weeks and then these same diets with 0.5% (w/w) clofibric acid (the direct acting hydrolysis product of clofibrate) or 0.02% (w/w) perfluorooctanoic acid (PFOA) for 10 days. Other groups of rats received radiolabeled clofibrate by intubation. Clofibric acid was an ineffective as clofibrate in producing effects (i.e. decreased body weight gain, increases in liver somatic index and protein content of the mitochondrial fraction, and increased activities of catalase and peroxisomal fatty acid beta-oxidation) in the liver of Se-deficient rats. Microsomal omega-hydroxylation was, however, equally induced in both dietary groups. In contrast to clofibric acid, the biological effects of PFOA were not affected by Se status. Furthermore, neither the tissue distribution (plasma, liver and kidney) nor the urinary excretion of 14C was affected by Se deficiency. These results demonstrate that the hydrolysis of clofibrate to clofibric acid is not impaired in the Se-deficient rat. In addition, the involvement of Se in the effects of peroxisome proliferators differs for different members of this structurally heterogeneous group of compounds. It is concluded that the Se-deficient rat may provide valuable information concerning the biochemical mechanism(s) underlying peroxisome proliferation.

Animals↗
PubMed1993

Automated sample clean-up with solid-phase extraction for the determination of aflatoxins in urine by liquid chromatography.

An automated extraction and clean-up procedure was developed for the determination of aflatoxins in human urine at the 50 pg/ml level. Aflatoxins B1, B2, G1 and G2 are captured on C2 extraction columns and simultaneously cleaned up with the aid of a robotic system. The processed samples are analysed by reversed-phase high-performance liquid chromatography. Fluorescence detection was enhanced for aflatoxins B1 and G1 using factorial design optimization of the post-column reactor. Silylation of the glass vials used in the robotic system was of the utmost importance. With non-silylated glass vials, up to 75% of the analytes were lost. Average aflatoxin recoveries were B1 95%, B2 90%, G1 93% and G2 89%.

Aflatoxins↗
PubMed1993

Nicotine and its major metabolite cotinine have different effects on aldosterone and prolactin serum levels in the normal male rat.

Nicotine (0.01-1.0 mg/kg, i.p.) or cotinine (0.003-1.0 mg/kg, i.p.) treatment was administered to Sprague-Dawley male rats. The time-effect curves (5, 10, 30, 60 and 180 min) were analyzed. Nicotine dose-dependently increased blood aldosterone and corticosterone levels with a peak effect 10 min after the intraperitoneal injection. Nicotine treatment weakly decreased serum levels of aldosterone at 2 h, possibly as a consequence of nicotine metabolising to cotinine, resulting in higher serum levels of cotinine than nicotine. Cotinine dose-dependently reduced serum aldosterone levels, an effect which became more marked with time, leaving plasma corticosterone unchanged. Nicotine dose-dependently increased serum prolactin levels at 5 and 10 min following treatment, an effect which had diminished at 30 min. Cotinine dose-dependently reduced serum prolactin levels at 5 min followed by a dose-dependent increase at 10 min after which a dose-dependent reduction was again found after 30 min post treatment. In conclusion, acute nicotine and cotinine treatment produced opposite effects on aldosterone and prolactin serum levels. The prolonged effect of cotinine on aldosterone levels may be involved in changes in brain function, and may be connected to the development of withdrawal effects after stopping cigarette smoking. As reported by other investigators, nicotine produced enhanced plasma corticosterone levels while cotinine treatment was ineffective. Since cotinine induced marked changes in serum prolactin levels while leaving LH levels unchanged, it seems plausible that cotinine affects neuroendocrine regulation via mechanisms not primarily related to circulatory effects. Thus, an action at the median eminence--pituitary level seems likely.

Aldosterone↗
PubMed1993

[Alcohol education among junior high school students. Results from a WHO educational program].

A school-based social influences approach to alcohol education was tested among Norwegian 8th grade lower secondary school students. The goal of the programme was to delay onset and minimize involvement in use of alcohol among the participants. 15 schools were randomly assigned to peer-led education, teacher-led education or a control condition. The programme focused on the social and environmental influences to drink alcohol, and skills to resist those influences. It consisted of five lessons over two months. Baseline and post-test data measured alcohol-use, knowledge, attitudes, skills, friends' drinking, and intentions to drink alcohol in the future. Data were collected immediately prior to and following the educational programme. The data indicate that peer-led education appears to be efficacious in reducing alcohol use and intention to use alcohol. There was no intervention effect of the peer-led programme for knowledge, attitudes or skills. There was no intervention effect for the teacher-led education.

Adolescent↗
PubMed1993

Time-dependent changes in enterochromaffin-like cell kinetics in stomach of hypergastrinemic rats.

BACKGROUND: Hypergastrinemia has been claimed to cause first hyperplasia and then dysplasia/neoplasia of enterochromaffin-like (ECL) cells in rat stomach. The growth is thought to reflect an accelerated self replication rate of mature ECL cells. The cytokinetics and the histidine decarboxylase (HDC) activity of the ECL cells were investigated during sustained hypergastrinemia. METHODS: Hypergastrinemia was evoked by omeprazole (400 mumol.kg-1 x day-1 orally) for up to 1 year. Immunocytochemistry for histamine was used to determine the ECL cell density and combined with [H3]-thymidine autoradiography to establish the labeling index (LI), i.e., the proportion of the ECL cells that has incorporated [H3]thymidine. RESULTS: The ECL cell density increased progressively for 10-20 weeks in response to the hypergastrinemia and remained at a plateau for the remainder of the study. The hyperplasia was diffuse with additional micronodules at 52 weeks. The ECL cell Ll was maximally elevated after 1-2 weeks and declined to control values after 10-20 weeks of treatment. In contrast, the HDC activity remained elevated for the duration of the study. CONCLUSIONS: The ECL cell hyperplasia reflects the transiently elevated ECL cell Ll during the early phase but is not associated with an accelerated rate of mitosis during the 10-52 weeks period. Even though with time gastrin seems to loose its ability to sustain a high ECL cell Ll it retains its ability to maintain a high HDC activity.

Animals↗
PubMed1993

Liquid-liquid partition chromatography as a method to examine surface properties of antibodies and antigen-antibody complexes.

We demonstrate liquid-liquid partition chromatography in aqueous two-phase systems (LLPC) as a simple method for examining the surface properties of immunoglobulins and antigen-antibody complexes in solution. LLPC separates molecules with respect to the properties of the exposed surfaces. As an example, the method may be used to detect changes in the conformation of IgG following chemical modification like acylation or iodination. We have studied the partitioning of antibodies and antigen-antibody complexes, modelled by rabbit antibodies against three human serum proteins, in aqueous polyethylene glycol/dextran two-phase systems at pH 7. Analysis of both polyclonal and monoclonal antibodies against various antigens suggested that the partition properties of immunoglobulins are related mainly to their antigen specificity and not to subclass-specific structures. Furthermore, experiments indicated that changes in the surface properties of antigen and/or antibody following complexation may be detected. Thus, LLPC may prove to be a new way of studying the relation between antibody structure and function in solution.

Acylation↗
PubMed1993

Effect of selecting for increased lean tissue growth rate in swine on low or high dietary protein levels.

To determine the optimum nutritional status when selecting for increased daily lean tissue growth rate (LTGR) two selection lines of Swedish Yorkshire pigs were tested for responses and interactions when fed three diets that contained .70, .85, or 1.00% lysine and 13.9, 15.8, or 17.5% CP, respectively. Selection for increased LTGR was made while the pigs were fed diets with low CP (13.1%) and lysine (.64%) (LP line) or high CP (18.5%) and lysine (.96%) (HP line) concentrations. Two experiments were performed after three generations of selection, with pigs fed from 25 to 105 kg BW. The animals were fed restrictedly on an energy basis in relation to BW. A total of 236 pigs were tested. When testing main effects of selection line, the HP line had superior average daily lean tissue gain (P = .031), carcass lean percentage (P = .007), and lean to feed ratio (P = .028) compared with the LP line. No diet x genotype interaction was found for any of the traits tested. The selection in the HP line resulted in faster genetic progress because this line had best overall performance. This supports the theory that the most efficient selection is achieved in an environment that enables the animals to express their genetic capacity for the desired trait.

Adipose Tissue↗
PubMed1993

Effects of hypercholecystokininemia produced by pancreaticobiliary diversion on pancreatic growth and enzyme mRNA levels in starved rats.

The purpose of the present study was to examine the weight, DNA content, and enzyme mRNA levels in the pancreas in response to endogenous hypercholecystokininemia produced by pancreaticobiliary diversion (PBD) in starved rats. The results showed that PBD, which is known to increase the circulating cholecystokinin (CCK) concentration, prevented the reduction in the weight and DNA content of the pancreas after 3 days of starving, and that PBD increased the mRNA levels of amylase, chymotrypsinogen B, and procarboxypeptidase A in the pancreas of starved rats. The findings support the view that endogenous CCK plays an important role in maintaining the weight of the normal pancreas of starved rats and that it stimulates the transcription of genes coding for pancreatic exocrine enzymes.

Actins↗
PubMed1993

Intravenous drug abuse--the major route of hepatitis C virus transmission among alcohol-dependent individuals?

As the prevalence of hepatitis C virus (HCV) antibodies has been reported to be high among alcohol-dependent individuals, we screened prospectively 310 consecutive non-selected alcoholic outpatients for HCV and possible routes of transmission. Using a second-generation enzyme-linked immunosorbent assay test and retesting all positive sera with a second-generation recombinant immunoblot assay, we found the prevalence of anti-HCV to be 14.5% (45 of 310). Of the 45 anti-HCV-positive individuals, 39 (88.7%) had a history of intravenous drug abuse, 2 had received blood transfusions, and only 4 lacked an identifiable source of infection. The magnitude of alcohol consumption, number of hospital admissions, duration of alcohol dependence, or presence of tattooing could not be shown to be factors of importance for the transmission of HCV infection. Our results suggest that a history of intravenous drug abuse is a common phenomenon and the predominant route of HCV transmission among alcoholics. True community-acquired infection would appear to be rare.

Adult↗
PubMed1993

Effects of perfluoro fatty acids on peroxisome proliferation and mitochondrial size in mouse liver: dose and time factors and effect of chain length.

1. Male mice were fed a diet containing perfluoro fatty acids of varying chain length (i.e. perfluoroacetic, -butyric, -octanoic and -decanoic acids) at different doses (0.02 or 0.1% w/w of diet) for different periods of time (2-10 days), and effects on liver weight, hepatic mitochondrial protein and hepatic peroxisomal palmitoyl-CoA oxidation, lauroyl-CoA oxidase and catalase were monitored. 2. The greatest effects were obtained with perfluoro-octanoic and perfluoro decanoic acids, while perfluoro acetic acid was inactive. The effects with 0.02% w/w of diet perfluoro-octanoic acid were at least as great as those observed with 0.1%. A more detailed dose-response investigation focused on perfluoro-octanoic acid revealed that maximal effects with this substance could be obtained with a dietary dose of 0.01% for 10 days and that significant changes were also observed with 0.001%. 3. Maximal effects with 0.02% w/w of diet perfluoro-octanoic acid were attained after 6-10 days of feeding. 4. As with other peroxisome proliferators, perfluoro fatty acids increase mouse hepatic peroxisomal fatty acid beta-oxidation more extensively than they increase catalase, thus increasing hepatic oxidative stress. 5. As with other peroxisome proliferators, perfluoro fatty acids increase mouse liver mitochondrial protein. This effect is due primarily to a redistribution of mitochondria from the nuclear to the mitochondrial fraction, caused by an apparent decrease in the mean size of hepatic mitochondria after treatment.

Acyl-CoA Oxidase↗
PubMed1993

Hormonal intrauterine devices.

Intrauterine administration of progestogens from an IUD was introduced more than 15 years ago in order to improve the contraceptive efficacy and to reduce side-effects. A device releasing 20 micrograms levonorgestrel daily (Levonova) with a life span of at least 5 years is now available and has been subjected to an extensive study including 1821 women followed during 5 years. The safety and efficacy were evaluated in comparison to Cu-T IUDs. The pregnancy rate (Pearl index) was 0.09. During the first two cycles after insertion intermenstrual bleeding was common, otherwise the frequency of side-effects was low. The results seem to justify the conclusion that intrauterine administration of progestogens represents a further development of IUDs and hormonal contraception. Furthermore, these devices have proven to be effective in treatment of heavy menstrual blood losses. In many menorrhagic women, use of these IUDs can replace more invasive surgical methods such as hysterectomy or endometrial resection. Intrauterine administration of progestogens is also effective in opposing the proliferative effect of oestrogen on the endometrium in women on hormonal replacement therapy.

Adolescent↗