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Biomedical subjects

A Karlsson

Publications and source records attributed to A Karlsson.

At least 19 recordsLinked to original sources
PubMed1992

Neurons in the cockroach nervous system reacting with antisera to the neuropeptide leucokinin I.

Antisera were raised against the myotropic neuropeptide leucokinin I, originally isolated from head extracts of the cockroach Leucophaea maderae. Processes of leucokinin I immunoreactive (LKIR) neurons were distributed throughout the nervous system, but immunoreactive cell bodies were not found in all neuromeres. In the brain, about 160 LKIR cell bodies were distributed in the protocerebrum and optic lobes (no LKIR cell bodies were found in the deuto- and tritocerebrum). In the ventral ganglia, LKIR cell bodies were seen distributed as follows: eight (weakly immunoreactive) in the subesophageal ganglion; about six larger and bilateral clusters of 5 smaller in each of the three thoracic ganglia, and in each of the abdominal ganglia, two pairs of strongly immunoreactive cell bodies were resolved. Many of the LKIR neurons could be described in detail. In the optic lobes, immunoreactive neurons innervate the medulla and accessory medulla. In the brain, three pairs of bilateral LKIR neurons supply branches to distinct sets of nonglomerular neuropil, and two pairs of descending neurons connect the posterior protocerebrum to the antennal lobes and all the ventral ganglia. Other brain neurons innervate the central body, tritocerebrum, and nonglomerular neuropil in protocerebrum. LKIR neurons of the median and lateral neurosecretory cell groups send axons to the corpora cardiaca, frontal ganglion, and tritocerebrum. In the muscle layer of the foregut (crop), bi- and multipolar LKIR neurons with axons running to the retrocerebral complex were resolved. The LKIR neurons in the abdominal ganglia form efferent axons supplying the lateral cardiac nerves, spiracles, and the segmental perivisceral organs. The distribution of immunoreactivity indicates roles for leucokinins as neuromodulators or neurotransmitters in central interneurons arborizing in different portions of the brain, visual system, and ventral ganglia. Also, a function in circuits regulating feeding can be presumed. Furthermore, a role in regulation of heart and possibly respiration can be suggested, and probably leucokinins are released from corpora cardiaca as neurohormones. Leucokinins were isolated by their myotropic action on the Leucophaea hindgut, but no innervation of this portion of the gut could be demonstrated. The distribution of leucokinin immunoreactivity was compared to immunolabeling with antisera against vertebrate tachykinins and lysine vasopressin.

Animals↗
PubMed1992

The HIV replication inhibitor 3'-fluoro-3'-deoxythymidine blocks sialylation of N-linked oligosaccharides.

The ability of 3'-fluoro-3'-deoxythymidine (FLT) to interfere with glycosylation was investigated in an experimental system, where the effects on the herpes simplex virus type 1-specified glycoprotein gC were determined. By adding FLT to HSV-infected cells after the peak of DNA synthesis, it was possible to segregate possible effects on nucleic acid metabolism from the effects on glycosylation of gC. It was found that FLT treatment of HSV-infected cells at concentrations of 20-500 micrograms/ml resulted in a significant increase in the electrophoretic mobility of gC, indicating a reduction of the amount of carbohydrates incorporated into gC. Lectin-binding assays demonstrated that the FLT treatment blocked addition of sialic acid to complex type N-linked glycans. The effects on glycosylation were observed in cells infected with an HSV mutant, deficient in thymidine kinase (TK), but not in cells infected with wild type virus. The cells infected with the wild type virus contained five times more total FLT metabolites than the cells infected with the TK-deficient mutant, whereas the latter cell type contained significantly higher amounts of unmetabolized FLT. This result indicates that FLT itself, and not a metabolite, was responsible for the effects on glycosylation.

Antibodies, Monoclonal↗
PubMed1992

HIV-1 reverse transcriptase inhibiting antibody titer in serum: relation to disease progression and to core-antibody levels.

A new assay for detecting inhibition of reverse transcriptase activity (the RT-i REA) was developed. This assay was standardized for screening serum samples for reverse transcriptase inhibiting antibodies (RT-iAb). High specificity (100%) and sensitivity (greater than 98%) were achieved with samples from HIV-negative individuals and HIV-infected individuals. The RT-i REA was also used in a study of the titers of RT-iAb in serum samples obtained from 33 HIV-infected homosexual men. The results confirmed the relation between decreasing RT-iAb levels and progression to late stages of the disease. Furthermore, a falling RT-iAb titer was observed in 14 of 15 individuals experiencing periods of severe clinical symptoms attributed to HIV-activity. In 7 of the patients the decline in RT-iAb titer began prior to severe clinical symptoms. The fall in RT-iAb titer also correlated with a reduction in core Ab level. The core Ab level has previously been reported to be a disease progression marker with considerable prognostic value. However, whereas all patients were positive for RT-iAb, 8 of the 33 patients did not have detectable core Ab. The use of RT-iAb titer as a marker of disease progression is discussed.

Acquired Immunodeficiency Syndrome↗
PubMed1992

A study of autoimmune gastritis in the postpartum period and at a 5-year follow-up.

The presence of autoimmune gastritis was investigated in 54 women with postpartum thyroiditis. Parietal cell antibodies (PCA) specific against H+, K(+)-adenosine triphosphatase (EC 3.6.1.36) were found in 18 women during pregnancy; in 10 of them, a 2-9-fold increase in the PCA level was observed in the postpartum period. At a 5-year follow-up, the initially PCA-positive women still had elevated antibody levels. Hypergastrinemia and low pepsinogen levels were noted in 4 women. In 2 of these women low serum vitamin B12 levels had developed. In 6 of 9 PCA-positive women examined by gastroscopy, biopsy specimens from the gastric body mucosa contained mononuclear cells, mainly T lymphocytes (CD3+) and macrophages (Leu-M3+) combined with an aberrant epithelial expression of HLA-DR. In four patients with chronic gastritis, all parietal cells, as defined by a specific monoclonal antibody, were found to have immunoglobulin G (IgG) deposits by a double-immunostaining method. Three of them had microscopic evidence of atrophy, whereas in 1 patient the body mucosa was intact. In 1 further patient with intact glands at histological examination, the basolateral membrane of some oxyntic glands was coated with IgG. The selective in situ deposition of antibodies associated with histologically intact parietal cells may support the concept that specific autoantibodies participate in the early pathogenesis of parietal cell destruction.

Adenosine Triphosphatases↗
PubMed1992

One-year follow-up on the safety and efficacy of isoprinosine for human immunodeficiency virus infection. Scandinavian Isoprinosine Study Group.

The safety and clinical impact of isoprinosine in HIV-infected individuals were assessed in a multicentre, randomized, double-blind, 24-week study phase, followed by an optional 24-week open treatment phase. The results of the double-blind phase have been reported. Of 866 HIV-seropositive patients randomized, 832 subjects were eligible for efficacy analysis. On completion of the double-blind phase, 596 patients started open treatment. All patients were evaluated with regard to progression to AIDS and/or death. Within 48 weeks, 10/412 (2.4%) patients assigned isoprinosine and 27/420 (6.4%) patients assigned placebo progressed to AIDS (P = 0.005). Intention-to-treat analysis showed identical results. Viewing the open treatment phase in isolation revealed no difference in progression rates between those treated and those not receiving the drug, perhaps reflecting the higher proportion of patients receiving zidovudine or PCP prophylaxis in the latter group. No severe adverse reactions or toxicities were observed. We conclude that HIV-seropositive patients without AIDS may be safely and effectively treated with isoprinosine.

Acquired Immunodeficiency Syndrome↗
PubMed1992

Phagocytosis following translocation of the neutrophil b-cytochrome from the specific granule to the plasma membrane is associated with an increased leakage of reactive oxygen species.

The effect of neutrophil b-cytochrome translocation on the respiratory burst activation generated during phagocytosis of yeast particles was investigated. Secretion of neutrophil specific granules was induced by the calcium ionophore ionomycin prior to phagocytosis. The secretory process is associated with a translocation from the specific granules to the plasma membrane of the respiratory burst b-cytochrome. Respiratory burst activity was measured as release of hydrogen peroxide in the absence of azide (extracellular leakage) and in the presence of azide (total production). The subcellular localization of the b-cytochrome was found to affect the extracellular release of hydrogen peroxide in that a plasma membrane localization was associated with a significantly increased release during phagocytosis. It should be pointed out, however, that most of the hydrogen peroxide, both in control and in ionomycin-treated cells, is produced intracellularly, probably in the phagosomes.

Adult↗
PubMed1992

Lansoprazole and omeprazole have similar effects on plasma gastrin levels, enterochromaffin-like cells, gastrin cells and somatostatin cells in the rat stomach.

This study compares the effects of lansoprazole and omeprazole on the activation and proliferation of enterochromaffin-like (ECL) cells in the rat stomach. Lansoprazole was given orally once daily for 10 weeks in two doses, 135 and 200 mumol/kg. Omeprazole was given by the same regimen in a dose of 400 mumol/kg, which is equipotent in terms of acid inhibition to the higher lansoprazole dose. Lansoprazole (both doses) as well as omeprazole raised the plasma gastrin levels about 11-fold 2 h after dosing and 8-to 10-fold 24 h after dosing, reflecting complete (2 h) and 70-80% (24 h) reductions of gastric acid secretion. Administration of either drug for 10 weeks increased the weight of the stomach and the oxyntic mucosa. The oxyntic mucosal histidine decarboxylase activity, histamine concentration and ECL cell density were increased to the same extent in the rats given either of the two lansoprazole doses or omeprazole. The numbers of antral gastrin cells were doubled and the numbers of antral somatostatin cells half that in the controls. These results show that long-standing lansoprazole-evoked hypergastrinemia affects the ECL cell similarly to omeprazole, ranitidine and other acid secretion inhibitors.

2-Pyridinylmethylsulfinylbenzimidazoles↗
PubMed1992

Contrast medium injected into juvenile bone cysts to analyze interior morphology and guide intracavity corticosteroid treatment.

In connection with treating juvenile bone cysts with intracavital corticosteroid injections, the interior cyst anatomy was analyzed at cystography in 13 children aged 4 to 15 years. Only 4 children had a true unicameral cyst; the others had 2 or more cysts or had compartments with free or restricted communication to the main cyst. Cysts and compartments which had not been reached by steroids may continue to grow. Optimum treatment may therefore require injections at different sites guided by cystography. Neither conventional criteria of cyst activity nor repeated bone scintigraphy 3 months after treatment could predict whether the treatment would lead to final healing.

Adolescent↗
PubMed1991

Stressful life events and Graves' disease.

The role of stressful life events in the onset of Graves' disease (toxic diffuse goitre) is controversial. However, the numerous early clinical reports that supported such an association were not adequately controlled and specificity of the diagnosis could be questioned. Later studies have not shown a causal relation, but these studies were small, did not have proper controls, or epidemiological methods were inappropriate. To assess possible associations between life events, heredity, social support, and Graves' disease, we have done a population-based case-control study in a defined area with about 1 million inhabitants. Over 2 years, 208 (95%) of 219 eligible patients with newly-diagnosed Graves' disease and 372 (80%) of all selected matched controls answered an identical mailed questionnaire about marital status, occupation, drinking and smoking habits, physical activity, familial occurrence of thyroid disease, life events, social support, and personality. Compared with controls, patients claimed to have had more negative life events in the 12 months preceding the diagnosis, and negative life-event scores were also significantly higher (odds ratio 6.3, 95% confidence interval 2.7-14.7, for the category with the highest negative score). Individuals who had relatives with thyroid disease (especially first-degree and second-degree relatives) were more likely to have Graves' disease (3.6, 2.2-5.9). Slightly more patients than controls were divorced (1.8, 1.0-3.3) and reported a less frequent intake of alcohol (0.4, 0.2-0.8). When results were adjusted for possible confounding factors in multivariate analyses, risk estimates were almost unchanged. These findings indicate that negative life events and hereditary factors may be risk factors for Graves' disease.

Adult↗
PubMed1991

HIV reverse transcriptase inhibiting antibodies detected by a new technique: relation to p24 and gp41 antibodies, HIV antigenemia and clinical variables.

A new assay for HIV reverse transcriptase activity inhibiting antibodies (RTI-ab) was used for the analysis of a large collection of sera sampled before and after confirmation of HIV infection. In this assay HIV-RT was preincubated with diluted serum, after which residual RT activity was determined by a technique using a template coupled to macrobeads and 125I-lodo-deoxyuridine-triphosphate as the tracer-substrate. Of the 936 sera analysed, 818 were found positive for RTI-ab, and 824 were positive in Western blot (Wb). The prevalence of RTI-ab compared to Wb was therefore 99.3%. The corresponding figure for 930 sera analysed for envelope-ab, i.e., gp41-ab, was 823 positive, and of these 930 sera 815 were Wb positive, giving a comparative prevalence of 101%. In contrast, only 678 samples of 993 analyzed for core ab, i.e., p24, were positive, giving a prevalence of 77.0% as 880 of these samples were Wb positive. Thus, RTI-ab was as prevalent as gp41-ab, and although the analyses of RTI-ab amounts in different stages showed decreasing levels in stage IV compared to stages II or III, all of the sera except 1 were found positive in stages III and IV. Further, it was found that both the few RTI-ab negative samples in stage II and the few RTI-ab positive samples among Wb negative sera were sampled in connection with seroconversion. The specificity of the RTI-ab assay was 100% in a test of 200 serum samples from HIV negative blood donors. It was concluded that RTI-ab analyses can be made highly sensitive and specific and useful for studies of HIV infection.

AIDS Serodiagnosis↗
PubMed1991

Gasoline pump mechanics had increased frequencies and sizes of micronuclei in lymphocytes stimulated by pokeweed mitogen.

Fifteen gasoline pump mechanics and 15 controls were investigated with the lymphocyte micronucleus assay and also with differential count of leukocytes in the peripheral blood. The lymphocytes were stimulated with phytohemagglutinin and pokeweed mitogen in parallel cultures. The pump mechanics had increased frequencies and sizes of micronuclei in the pokeweed mitogen-stimulated cultures but not in those stimulated with phytohemagglutinin. The difference in effect between the 2 mitogens is probably due to an increased sensitivity of the B-lymphocytes to mutagens. The leukocyte count was significantly higher in the gasoline-exposed group. The effect of the occupational exposure was probably caused by the benzene content of the gasoline. The time-weighted average for 8 h was around 1 mg/m3 of benzene, but there were peak levels of 20 mg/m3.

Adult↗
PubMed1991

Evaluation of the E test for susceptibility testing of anaerobic bacteria.

The susceptibilities of 105 clinical isolates of anaerobic bacteria were determined by a new method, the E test (AB Biodisk, Solna, Sweden), and were compared with the MICs for these organisms obtained by the reference agar dilution method by using supplemented brucella and Wilkins-Chalgren agars. The E test is a plastic strip with a predefined antibiotic gradient immobilized on one side and a MIC interpretive scale printed on the other side. Strips with cefoxitin, cefotaxime, imipenem, penicillin, metronidazole, and clindamycin were used in this study. A suspension of the test strain equal to the visual turbidity of a no. 0.5 McFarland standard was prepared and swabbed onto a 150-mm-diameter plate. The strips were applied in a radial fashion, and the plates were incubated under anaerobic conditions. After growth had occurred, an ellipse of inhibition was seen around each strip. At the point of intersection of the ellipse with the strip, the MIC was read from the interpretive scale. For most antibiotic-organism combinations, the ellipse was clear and the endpoint was sharp. The E-test MICs were interpreted after overnight and 48-h incubation for 58 of the strains. After overnight incubation, 87% of the E-test MICs were within 1 dilution of the agar dilution MICs, and 98% were within 2 dilutions. After 48 h of incubation, agreement was 86 and 97% respectively. E-test MICs obtained for the Bacteroides fragilis group after overnight incubation were more comparable than those obtained after 48 h of incubation to agar dilution MICs determined at 48 h for all drugs except clindamycin. On brucella agar, there was a 2% categorical discrepancy rate between the E-test MICs and agar dilution MICs, which occurred mostly with cefoxitin. The E test is easy to perform and read, is suitable for all anaerobes, can be used to test single patient isolates as needed, and offers the laboratory a reliable method for susceptibility testing of anaerobic bacteria.

Bacteria, Anaerobic↗
PubMed1991

Pretreatment with betamethasone of patients with Graves' disease given radioiodine therapy: thyroid autoantibody responses and outcome of therapy.

The effects of betamethasone on thyroid autoantibody responses and outcome of radioiodine therapy were determined over a period of 1 yr in a prospective randomized study of 40 patients with Graves' disease. Twenty patients were given placebo tablets, and 20 patients were treated with beta-methasone from 3 weeks before until 4 weeks after 131I therapy. At the time of inclusion in the study, the mean serum concentrations of TSH receptor antibodies, thyroid peroxidase antibodies, and thyroglobulin antibodies (TgAb) were increased in both groups. Three weeks of treatment with betamethasone reduced the thyroid peroxidase antibody and TgAb titers as well as the serum concentrations of thyroid hormones. A decrease in the TSH receptor antibody level was not statistically significant. After radioiodine therapy, transient increases in thyroid autoantibody levels were observed. The titers of the different antibodies generally changed in parallel. In some patients a detectable level of a given antibody was found only after the radioiodine treatment, and in two cases, TgAb did not appear at all, although the two other antibodies increased temporarily. Betamethasone delayed, but did not abolish, the 131I-induced antibody peaks. Betamethasone also caused a reduction in the total serum immunoglobulin G, a reduction which persisted throughout the study period. When the study ended, 17 patients given placebo and 9 patients given betamethasone (P less than 0.001) were receiving replacement therapy due to the development of hypothyroidism. These patients at this point in time had lower antibody levels than those not requiring T4. The results of this study demonstrate that betamethasone reduces and modifies the thyroid autoantibody responses as well as the outcome of radioiodine therapy in patients with Graves' disease. From a clinical point of view, these effects may be in opposite directions.

Aged↗
PubMed1991

A prospective study of 115 initially asymptomatic HIV infected gay men in Stockholm, Sweden.

A cohort of 115 asymptomatic gay men, all seropositive for HIV, was recruited in a health screening project in Stockholm, Sweden, between Nov. 1982 and Dec. 1983 and subsequently followed and clinically evaluated after a mean observation time of 63 months. AIDS in accordance with the surveillance definition (CDC group IV C-1 and D) developed in 34 (29.6%) of the men, while 1 (0.9%) additional man died of multiple myeloma classified as CDC group IV E. Constitutional symptoms (CDC group IV A) developed in 13 (11.3%) men, while symptoms from the central nervous system classified as CDC group IV B occurred in 1 (0.9%) additional man. Minor opportunistic infections included in the definition for CDC group IV C-2 developed in 12 (10.4%) men, while 48 (41.7%) men remained asymptomatic, with or without persistent generalized lymphadenopathy (PGL). One man who died of AIDS had been treated for malignant melanoma (MM) and one who did not fulfill the criteria for CDC group IV died of MM during the observation period. The 5-year actuarial progression rate to surveillance defined AIDS was 31.5% and to CDC group IV 53.6%. No statistically significant association was found between disease progression and a number of recorded epidemiological variables, most previous and present sexually transmitted diseases (STD) (except gonorrhoea) and the presence of PGL at entry. On the other hand, reduced delayed cutaneous hypersensitivity, in particular to tuberculin, as well as the presence of a high IgG titer against cytomegalovirus (CMV), were correlated to disease progression.

Acquired Immunodeficiency Syndrome↗
PubMed1991

Effects of occupational exposure to mercury vapor on lymphocyte micronuclei.

For 26 chloralkali workers exposed to inorganic mercury and 26 age-matched, occupationally unexposed referents, the frequency and size distribution of micronuclei were determined in peripheral lymphocytes stimulated with either phytohemagglutinin or pokeweed mitogen. For the exposed workers the mean concentrations of mercury in urine, plasma, and erythrocytes were 16 nmol/mmol of creatinine, 48 nmol/l, and 78 nmol/l, respectively, and their mean exposure time was 10 years. Neither the frequency nor the size of micronuclei was significantly different in the two groups; nor were there any correlations to current mercury levels. However, in the exposed group, and with phytohemagglutinin as the mitogen, a statistically significant correlation between previous exposure to mercury (cumulative exposure or number of blood mercury peaks) and the frequency of micronuclei was found. This association was also present when the effects of age and smoking were allowed for, and it may indicate an accumulation of cytogenetic effects in T-lymphocytes.

Adult↗
PubMed1990

The efficacy of inosine pranobex in preventing the acquired immunodeficiency syndrome in patients with human immunodeficiency virus infection. The Scandinavian Isoprinosine Study Group.

We performed a randomized, double-blind, placebo-controlled trial to assess the efficacy and safety of inosine pranobex (Isoprinosine) [corrected] in the treatment of patients with human immunodeficiency virus (HIV) infection but without manifest acquired immunodeficiency syndrome (AIDS). A total of 866 patients were enrolled in 21 centers in Denmark and Sweden. The patients were stratified in three groups according to their CD4+ cell count and randomly assigned to receive either inosine pranobex (1 g three times a day) (n = 429) or matching placebo (n = 437) for 24 weeks. Of the 831 patients who could be evaluated, AIDS developed in 17 in the placebo group as compared with 2 in the inosine pranobex group (P less than 0.001; odds ratio, 8.6 [95 percent confidence limits, 2.2 and 52.6]). There were no significant differences between the groups with respect to changes in CD4+ cell count or the development of other HIV-related conditions, with the exception of thrush, which developed in fewer patients in the inosine pranobex group (P = 0.05). No serious side effects were observed. We conclude that treatment with inosine pranobex delays progression to AIDS in patients with HIV infection. The duration of this beneficial effect, the optimal dose, and the mode of action of inosine pranobex remain to be clarified.

Acquired Immunodeficiency Syndrome↗
PubMed1990

The metabolism of 3'-azido-2',3'-dideoxyguanosine in CEM cells.

When CEM cells were incubated with [3H]-labeled 3'-azido-2',3'-dideoxyguanosine (AzddGuo), the isotope was largely recovered as ribo- and deoxyribonucleotides in the acid soluble fraction of CEM cells, due to extensive catabolism of AzddGuo and recycling of the guanine formed by purine nucleoside phosphorylase. Only 10% was found as the AzddGuo nucleotides, with the diphosphate of AzddGuo as the dominating nucleotide at all time points. Thus nucleoside diphosphate kinase was rate limiting for the formation of AzddGuo triphosphate, responsible for the toxic and antiviral activity of the nucleoside. Inhibition of de novo deoxyribonucleotide synthesis with hydroxyurea increased the phosphorylation of AzddGuo twofold.

Antiviral Agents↗