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Biomedical subjects

A Berg

Publications and source records attributed to A Berg.

At least 163 records · Page 9Linked to original sources
PubMed1996

A novel physiological function for platelet-derived growth factor-BB in rat dermis.

1. The present experiments describe a role for platelet-derived growth factor-BB and cellular adhesion receptors towards extracellular matrix molecules (beta 1-integrins) in control of interstitial fluid pressure (Pif). 2. Pif was measured in rat skin with sharpened glass capillaries (3-7 microns) connected to a servocontrolled counter-pressure system. 3. The collagen and laminin-binding alpha 2 beta 1-integrin is involved in the control of Pif since subdermal injection (5 microliters) of monoclonal hamster anti-rat alpha 2 beta 1-integrin IgG (anti-alpha 2 beta 1) resulted in increased negativity of Pif. Control Pif averaged -0.88 +/- 0.23 mmHg (+/- S.D.) and decreased to -2.50 +/- 0.35 mmHg (P < 0.05) and -3.88 +/- 1.45 mmHg (P < 0.05) at anti-alpha 2 beta 1 concentrations of 0.56 and 1.12 mg ml-1, respectively. 4. The effect of anti-alpha 2 beta 1 was abolished when platelet-derived growth factor-BB (PDGF-BB) (200 ng ml-1) was injected together with anti-alpha 2 beta 1. 5. The time- and dose-responses of PDGF-BB to counteract increased negativity of Pif were studied further using dextran anaphylaxis as an experimental model inducing increased negativity of Pif in skin. Control Pif averaged -0.33 +/- 0.43 mmHg and fell to -4.10 +/- 1.47 mmHg within 10 min after dextran (P < 0.01). Subsequent subdermal injection of PDGF-BB at 200 ng ml-1 normalized Pif in 10-20 min which became -1.37 +/- 1.23 mmHg (P < 0.01 versus dextran, P > 0.05 versus control). PDGF-BB had little or no effect at 50 ng ml-1. PDGF-AA and basic fibroblast growth factor had no effect on Pif. 6. The in vivo function reported for PDGF-BB has not been described previously and provides further evidence for active participation of connective tissue cells in control of Pif by altering tension on extracellular matrix structures.

Animals↗
PubMed1996

NMR assignments and relaxation studies of Thiobacillus versutus ferrocytochrome c-550 indicate the presence of a highly mobile 13-residues long C-terminal tail.

Cytochrome c-550 of Thiobacillus versutus functions as an electron transfer protein in a chain of redox proteins that enables T. versutus to grow on methylamine. It is a single-heme protein of 134 residues, related to mitochondrial cytochrome c. Cytochrome c-550, as well as several other bacterial c2-type cytochromes, contain a C-terminal extension of 13-16 amino acids of unknown function, compared to mitochondrial cytochrome c. NMR experiments were performed to obtain structural and dynamic information on the protein in solution. For this purpose, T. versutus cytochrome c-550 was labeled with 15N and 13C using 13C-methanol grown Paracoccus denitrificans as a host for heterologous expression. NMR assignments were obtained for the 1H, 15N, and 13C nuclei in the backbone and the beta-positions of the protein and the secondary structure was determined. 15N-relaxation studies were performed to characterize the dynamic properties of the protein. The results indicate that the main part of T. versutus ferrocytochrome c-550 exists in solution as a rigid, well-ordered molecule with a secondary structure that is very similar to that of P. denitrificans cytochrome c-550, as observed in crystals. The C-terminal extension, however, is unstructured and highly mobile. The possible origin and function of the extension are discussed.

Amino Acid Sequence↗
PubMed1996

Pre-immunotherapy serum CA27.29 (MUC-1) mucin level and CD69+ lymphocytes correlate with effects of Theratope sialyl-Tn-KLH cancer vaccine in active specific immunotherapy.

Patients with metastatic breast, colorectal or ovarian cancers received active specific immunotherapy (ASI) with Theratope sialyl-Tn-KLH (keyhole limpet hemocyanin) cancer vaccine emulsified in Detox adjuvant. The median log2 anti-STn IgG titer generated by ASI, estimated by enzyme-linked immunosorbent assay with solid-phase ovine submaxillary mucin, was 5.322 (range = 0 - 9.322). Following ASI, 51 patients who generated titers higher than the median value for anti-STn+ mucin IgG survived longer than 46 patients who generated lower titers below the median. 38 of the patients were phenotyped for CD69 prior to ASI. The patients with lower numbers of CD69+ peripheral blood lymphocytes prior to immunotherapy (pre-ASI) also had low serum CA27.29 cancer antigen (MUC-1) levels, and had longer times to disease progression and improved survival following ASI. Elevated pre-ASI serum CA27.29 tumor antigen levels were associated with higher numbers of CD69+ PBL, with decreased anti-STn antibody production and decreased survival following ASI. The data are compatible with the hypothesis that elevated serum MUC-1 mucin is specifically immunosuppressive.

Antigens, CD↗
PubMed1996

Coexisting left congenital diaphragmatic hernia and esophageal atresia with tracheoesophageal fistula: successful management in a premature neonate.

The combination of left congenital diaphragmatic hernia (CDH) with esophageal atresia (EA) and distal tracheoesophageal fistula (TEF) is extremely rare and is considered highly lethal. The authors describe a premature neonate with this association, who is alive at 6 1/2 years of age. Temporary banding of the gastroesophageal junction and gastrostomy was performed concurrently with hernia repair and prosthetic abdominoplasty to enlarge the abdominal cavity. A right thoracotomy for ligation of the fistula, using extracorporeal membrane oxygenation (ECMO), was performed 13 days later. Complete repair of the esophageal atresia was accomplished 7 weeks after birth. The methods that have been suggested in the literature are discussed. The institution of ECMO at birth could allow a primary complete surgical repair of EA and CDH. Nevertheless, surgical management with staged repair, as described herein, can be useful.

Abdomen↗
PubMed1996

RT-PCR based analysis of T-cell receptor B variable region gene usage in normal human breast skin resident T lymphocytes (SRT).

The skin interfaces directly with the external environment that contains innumerable infectious agents. Therefore, an appropriate and rapid immunologic response is required to preserve internal homeostasis. An essential feature of the "skin immuno system' (SIS) is the presence of substantial numbers of T cells in normal skin. The T-cell receptor repertoire from normal human breast skin was analysed quantitatively and qualitatively by using PCR amplification of reverse transcribed RNA, T-cell receptor BV3 and BV14 gene usage was increased in skir T lymphocytes in all individuals tested (n = 8) compared to peripheral blood CD4+ and CD8+ T lymphocytes from the same individuals. The T-cell receptor junctional diversity analysed by high resolution gel electrophoresis showed skin T-cell BV3 and BV14 gene usage to be predominantly polyclonal. Superantigen stimulation of T cells in human skin is considered a likely explanation of the present finding.

Breast↗
PubMed1996

Lipoprotein(a) in endurance athletes, power athletes, and sedentary controls.

Elevated concentrations of lipoprotein(a) [Lp(a)] have been shown to be an independent risk factor for atherosclerotic disease. Physical activity and physical fitness have been shown to improve lipoprotein metabolism and reduce the risk of coronary artery disease. Studies on the influence of physical activity and physical fitness on Lp(a) levels including a large number of endurance as well as power athletes have not been performed before. Therefore, we determined parameters of physical fitness (maximal oxygen consumption), physical activity, and lipoproteins in 105 endurance athletes, 57 power athletes, and 87 sedentary young men. As expected, we found that endurance athletes with a good physical fitness had significantly higher concentrations of high-density lipoprotein cholesterol than power athletes and sedentary controls. Regarding mean Lp(a) levels (rocket immunoelectrophoresis), however, there were no significant differences between endurance athletes, power athletes, and sedentary controls. Even when including only those with Lp(a) values > 10 mg.dl-1, no differences were observed between the groups. These findings indicate that intensive training over years and good aerobic fitness improve the ratio of low-density lipoprotein to high-density lipoprotein cholesterol but have no or only minor effects on Lp(a) concentrations.

Adult↗
PubMed1996

Effect of physical exercise and vitamin C on absorption of ferric sodium citrate.

The effect of physical exercise and vitamin C on iron absorption after oral iron administration was investigated. Eight healthy male subjects without iron deficiency were studied after administration of 100 mg ferric sodium citrate complex, 100 mg ferric sodium citrate complex with 200 mg ascorbic acid, and without iron intake, both under resting conditions and after a 1-h bicycle ergometer test at moderate exercise. Serum concentrations for iron, transferrin, and ferritin were measured before and 30 min, and 1, 2, and 4 h after each administration. Under resting conditions administration of 100 mg ferric sodium citrate led to a significant increase in serum iron concentrations. When ferric sodium citrate was administered with vitamin C, iron values increased significantly further. Ingestion of iron together with physical exercise resulted in a higher serum iron concentration than under resting conditions. The maximum increase, reached after 4 h, was 48.2% with exercise and 8.3% without. In combination with exercise, the addition of 200 mg vitamin C did not further increase serum iron concentration. In conclusion, 1 h of moderate exercise enhanced the rate of iron absorption. Under resting conditions the combination of ferric sodium citrate with vitamin C led to significantly increased postabsorption serum iron concentrations compared with iron administration without vitamin C.

Adult↗
PubMed1996

Epogam evening primrose oil treatment in atopic dermatitis and asthma.

Essential fatty acids are claimed to have positive effects in atopic diseases. In a double blind, placebo controlled, parallel group study 58 out of 60 children, with atopic dermatitis and the need for regular treatment with topical skin steroids, completed a 16 weeks' treatment period with either Epogam evening primrose oil or placebo capsules. Twenty two of these subjects also had asthma. The parents used diaries to record symptom scores and concomitant medication. Peak expiratory flow was measured and disease activity was monitored by the clinician every four weeks. The plasma concentrations of essential fatty acids increased significantly in the group treated with Epogam capsules. The study demonstrated significant improvements of the eczema symptoms but no significant difference was found between the placebo and the Epogam groups. No therapeutic effect was shown on asthma symptoms or fidget.

Administration, Topical↗
PubMed1996

Association between serum fibrinogen concentrations and HDL and LDL subfraction phenotypes in healthy men.

Hyperfibrinogenemia and a dyslipoproteinemia characterized by reduced HDL2 cholesterol and elevated levels of small, dense LDL particles are risk factors for coronary artery disease. However, the relationship between fibrinogen and lipoproteins, in particular LDL subfractions, is uncertain. We therefore measured serum fibrinogen levels and serum concentrations of cholesterol and apolipoproteins of VLDL, IDL, six LDL, and two HDL subfractions by using the technique of density-gradient ultracentrifugation in 132 nonsmoking men without evidence of coronary artery disease or infection. Dividing the individuals into quartiles according to their fibrinogen values showed that men within the highest fibrinogen quartile (fibrinogen 2.90 to 4.34 g/L) had significantly higher concentrations of small, dense LDL (d > 1.044 g/mL) apolipoprotein B and cholesterol and lower concentrations of HDL2 cholesterol than men within the lower fibrinogen quartiles (fibrinogen < 2.55 g/L). Multivariate regression analysis revealed that the association between fibrinogen and small, dense LDL particles was independent of serum triglycerides, cholesterol, body mass index, and age. In contrast, the relationship between fibrinogen and HDL2 cholesterol was primarily influenced by triglycerides and cholesterol and not independently influenced by fibrinogen. There were no significant differences between the quartiles in terms of insulin, glucose, insulin resistance, free fatty acids, lipoprotein(a), and blood pressure. This study showed that fibrinogen is associated with the expression of a more atherogenic LDL subfraction phenotype independent of body mass index, age, other serum lipids, and insulin resistance in a healthy male nonsmoking population. The reason for this association is uncertain. These findings reinforce the evidence that fibrinogen should be determined when assessing coronary risk.

Aging↗
PubMed1996

Suicidal chloral hydrate poisoning.

BACKGROUND: The cumulative reports of chlorate hydrate toxicity suggest an unacceptable risk for this commonly used sleep aid. CASE REPORT: A 29-year-old male was admitted after ingestion of 70 g of chloral hydrate. He was hypotensive and hypothermic. Spontaneous respiration was insufficient. Fluid resuscitation did not restore adequate blood pressure levels. Low dose catecholamine infusion resulted in ventricular arrhythmias. The patient was treated with combined hemoperfusion and hemodialysis during an eight hour period. During this time, serum concentrations of trichlorethanol fell. Blood pressure and heart rate increased and consciousness was regained without signs of neurological deficits. CONCLUSIONS: Although outcome was favorable, this case report illustrates the potentially high acute toxicity of chloral hydrate and supports its removal from the market.

Adult↗
PubMed1995

Sequential 1H and 15N nuclear magnetic resonance assignments and secondary structure of the lipoyl domain of the 2-oxoglutarate dehydrogenase complex from Azotobacter vinelandii. Evidence for high structural similarity with the lipoyl domain of the pyruvate dehydrogenase complex.

A 79-amino-acid polypeptide, corresponding to the lipoyl domain of the succinyltransferase component of the 2-oxoglutarate dehydrogenase multienzyme complex from Azotobacter vinelandii, has been sub-cloned and produced in Escherichia coli. Complete sequential 1H and 15N resonance assignments for the lipoyl domain have been obtained by using homo- and hetero-nuclear NMR spectroscopy. Two antiparallel beta-sheets of four strands each were identified from characteristic NOE connectivities and 3JHN alpha values. The lipoyl-lysine residue is found in a type-I turn connecting two beta-strands. The secondary structure of the lipoyl domain very much resembles the secondary solution structure of the N-terminal lipoyl domain of the A. vinelandii pyruvate dehydrogenase complex, despite the sequence identity of 25%. A detailed comparison of the NMR-derived parameters of both lipoyl domains, i.e. chemical shifts, NH-exchange rates, NOEs, and 3JHN alpha values suggests a high structural similarity in solution between the two lipoyl domains. Preliminary tertiary-structure calculations confirm that these lipoyl domains have very similar overall folds. The observed specificity of the 2-oxo acid dehydrogenase components of both complexes for these lipoyl domains is discussed in this respect.

Amino Acid Sequence↗
PubMed1995

1-O-hexadecyl-2-metoxy-glycero-3-phosphatidylcholine--a methoxy ether lipid inhibiting platelet activating factor-induced platelet aggregation and neutrophil oxidative metabolism.

Whether or not two alkylglycerols could initiate a functional response in human platelets or modify responses induced by platelet activating factor (PAF) was evaluated. It was found that 1-100 microM 1-O-hexadecyl-2-metoxy-glycero-3-phosphatidylcholine (Et-16-OCH3) induced platelet aggregation but 1-O-hexadecyl-sn-glycerol (chimyl alcohol; CA) did not. Et-16-OCH3-induced platelet aggregation was abolished by pretreatment with the PAF receptor antagonist WEB 2086. While CA had no effect on platelet aggregation induced by PAF, pretreatment with Et-16-OCH3 (0.1 microM or higher) significantly inhibited platelet aggregation induced by PAF, but had no effect on aggregation caused by ADP, thrombin or phorbol myristate acetate (PMA). A receptor binding study using radiolabelled [3H]WEB 2086 showed that Et-16-OCH3 exerts its actions through interaction with the PAF receptor. Moreover, Et-16-OCH3 inhibited neutrophil chemiluminescence responses induced by PAF, but not reactions to PMA or a formyl peptide. Finally, 1 microM Et-16-OCH3 induced a rise in the intracellular calcium concentration in platelets equal to that induced by PAF and also had an calcium ionophore-like effect at 100 microM. Thus, this study shows that Et-16-OCH3 is both a potent inducer of platelet aggregation and an inhibitor of PAF-induced platelet aggregation and neutrophil chemiluminescence, through interaction with the PAF receptor.

Azepines↗
PubMed1995

CD69+ and HLA-DR+ activation antigens on peripheral blood lymphocyte populations in metastatic breast and ovarian cancer patients: correlations with survival following active specific immunotherapy.

Lymphocyte activation markers CD69 and HLA-DR were studied in metastatic breast and ovarian cancer patients who received active specific immunotherapy (ASI) using cancer vaccines containing the synthetic tumor-associated antigen sialyl-Tn or the Thomsen-Friedenreich antigen conjugated to KLH plus DETOX adjuvant. Breast cancer patients who showed prolonged survival following ASI had lower numbers of total CD69+ and CD4+CD69+ cells prior to ASI compared to patients who died. However, following ASI, the surviving patients showed an increase in CD69+ and CD4+CD69+ cells and the deceased patients showed a decrease. A greater than 50% increase in the percentage of cells bearing the activation marker CD69 is associated with an increase in survival in both ovarian and breast cancer patients. In the surviving breast cancer patients there was a significant decrease in the percentage of non-B lymphocyte HLA-DR+ (CD20-HLA-DR+) cells following cyclophosphamide treatment. A strong positive correlation was found between lymphocyte populations CD20- HLA-DR+ and CD8+CD57+, a putative suppressor cell population. Breast cancer patients who showed a greater than median decrease in CD20-HLA-DR+ lymphocytes following cyclophosphamide treatment had a survival advantage over patients who had less than the median decrease in the percent CD20-HLA-DR+ lymphocytes.

Adenocarcinoma↗