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Biomedical subjects

A Rieger

Publications and source records attributed to A Rieger.

At least 91 records · Page 5Linked to original sources
PubMed1992

Epidermal Langerhans cells from normal human skin bind monomeric IgE via Fc epsilon RI.

Human epidermal Langerhans cells (LC) bearing IgE are found in disease states associated with hyperimmunoglobulinemia E. When studying the mechanism(s) underlying this phenomenon, immunohistology revealed that a majority of epidermal LC from normal skin of healthy individuals can specifically bind monomeric IgE. IgE binding to LC could neither be prevented by preincubation of the tissue with monoclonal antibodies (mAb) against either Fc epsilon RII/CD23 or Fc gamma RII/CD32, nor by the addition of lactose. However, binding could be entirely abrogated by preincubation with the anti-Fc epsilon RI alpha mAb 15-1, which interferes with IgE binding to Fc epsilon RI alpha gamma transfectants. These observations indicated that IgE binding to epidermal LC is mediated by Fc epsilon RI rather than by CD23, CD32, or the D-galactose-specific IgE-binding protein. This assumption gained support from our additional findings that: (a) the majority of LC exhibited distinct surface immunolabeling with the anti-Fc epsilon RI alpha mAbs 15-1 and 19-1, but not with any of eight different anti-Fc epsilon RII/CD23 mAbs; and (b) transcripts for the alpha, beta, and gamma chains of Fc epsilon RI could be amplified by polymerase chain reaction from RNA preparations of LC-enriched, but not of LC-depleted, epidermal cell suspensions. In view of the preeminent role of Fc epsilon RI crosslinking on mast cells and basophils in triggering the synthesis and release of mediators of allergic reactions, the demonstration of this receptor on epidermal LC may have important implications for our understanding of allergic reactions after epicutaneous contact with allergens.

Animals↗
PubMed1992

Mechanism of insulin resistance associated with liver cirrhosis.

Insulin-induced glucose metabolism was investigated in 26 patients with biopsy-proven liver cirrhosis and 10 control subjects. Two glucose clamp protocols together with continuous indirect calorimetry were performed to examine whether reduced rates of glucose oxidation and/or nonoxidative glucose metabolism explain insulin resistance in liver cirrhosis. Using a 4-hour, two-step protocol (0-2 hours, plasma glucose 5.2 mmol/L, plasma insulin 92 mU/L to test the half-maximum response; 2-4 hours, hyperglycemia 10.0 mmol/L, plasma insulin 442 mU/L to test the maximum cellular glucose disposal) liver cirrhosis reduced glucose disposal to 45% and 60% of control values, respectively. Simultaneously, insulin-induced increases in glucose oxidation, plasma lactate levels, and lipogenesis were normal, whereas nonoxidative glucose metabolism was reduced (-82% and -47% of controls, respectively). To determine whether reduced nonoxidative glucose metabolism was caused by reduced glucose disposal, glucose disposal was "matched" to normal values in a subgroup of cirrhotic patients. Nonoxidative glucose metabolism values were normal, but plasma lactate concentrations disproportionally increased (+96%) after "matching" glucose disposal. Insulin resistance was independent of the etiology of the cirrhosis, the biochemical parameters of parenchymal cell damage and liver function, and the clinical and nutritional state of the patients. It is concluded that liver cirrhosis impairs insulin sensitivity and maximum cellular glucose disposal. Reduced glucose disposal is caused by defective glucose storage. Insulin resistance is independent of the etiology of liver cirrhosis and of the clinical and nutritional state of the patient.

Adult↗
PubMed1992

Metabolic responses to lipid infusions in patients with liver cirrhosis.

Energy expenditure, whole body substrate oxidation rates and arterial substrate concentrations were measured in 14 patients with liver cirrhosis and 13 control subjects before and during sequential infusions of a long chain (LCT) or a medium chain triglyceride emulsion (MCT) without and with concomitant insulin plus glucose infusions. Resting energy expenditure, basal substrate oxidation rates and the arterial concentrations of glucose, lactate, triglycerides and ketones were normal, whereas plasma free fatty acids and glycerol were both increased in patients with liver cirrhosis. The arterial plasma triglyceride and free fatty acid concentrations as well as whole body lipid oxidation rate rose in response to LCT in both groups and the maximum lipid oxidation rate was 1.1 or 1.3 mg/kg fat free mass x min in controls and in cirrhotics, respectively (n.s.). Concomitantly, glucose oxidation rate fell to 65% of basal values in controls (p < 0.01), but remained nearly unchanged in the cirrhotic group (89% of the basal value; n.s.). The increase in plasma ketones was reduced to 67% of control values in liver cirrhosis (p < 0.01). Only a slight effect on energy expenditure was observed in both groups. When compared to controls, liver cirrhosis impaired insulin-induced increases in glucose disposal (-30%, p < 0.01) and in non oxidative glucose metabolism (-93%, p < 0.01). Concomitantly, normal increases in energy expenditure, glucose oxidation rate and the arterial plasma lactate concentrations and normal decreases in lipolysis, lipid oxidation and ketogenesis were observed in patients with liver cirrhosis. When lipids were given together with glucose, energy expenditure and lipid oxidation increased in controls, but glucose was the preferred fuel oxidised and lipid-induced thermogenesis was reduced in the cirrhotic group. Using a 50% MCT-emulsion, plasma free fatty acid concentrations further increased, but energy expenditure and lipid oxidation remained unchanged in both groups and further increases in plasma ketones were only observed in controls. Infusing glycerol in a subgroup of patients showed no thermogenic effect and a reduced glycerol clearance in liver cirrhosis.

Journal Article↗
PubMed1992

Resting energy expenditure and the thermic effect of adrenaline in patients with liver cirrhosis.

1. Resting energy expenditure and the metabolic responses to adrenaline (infusion rate: 0.03 micrograms min-1 kg-1 fat-free mass for 1 h) were investigated in 25 patients with liver cirrhosis. The patient group was heterogeneous and varied with respect to the aetiology of cirrhosis, the clinical condition (i.e. Child A or B), the nutritional status and the degree of hyperinsulinaemia. 2. When compared with 10 healthy control subjects the basal plasma adrenaline and noradrenaline concentrations were both increased in cirrhosis and remained elevated during adrenaline infusion (+39% and +31%, respectively; P < 0.05). Concomitantly, the peripheral plasma insulin concentration and the molar C-peptide/insulin ratio were increased in liver cirrhosis (+96% and +30%, respectively; P < 0.05). Hyperinsulinaemia was more pronounced in patients with ethanol-induced liver cirrhosis. 3. When expressed per kg fat-free mass, resting energy expenditure was enhanced in liver cirrhosis (+21%; P < 0.05) and was more pronounced (i.e. resting energy expenditures of +35% to +49% above estimated values) in patients with ethanol-induced cirrhosis, at advanced stages of the disease and in association with decreased body cell mass. 4. Infusion of adrenaline increased heart rate, O2 consumption and the plasma concentrations of glucose, lactate, free fatty acids, glycerol and 3-hydroxybutyrate, and similar transient increases and subsequent decreases in the respiratory quotient were observed in both groups. However, the lipolytic, ketogenic and thermic responses were reduced in cirrhotic patients. Reduced metabolic responses were more pronounced in hyperinsulinaemic patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

CD69, an early activation antigen on lymphocytes, is constitutively expressed by human epidermal Langerhans cells.

When screening skin cryosections with a panel of monoclonal antibodies (MoAb), we found that the anti-CD69 MoAb Leu-23 reacted with a subpopulation of epidermal dendritic cells, presumably Langerhans cells (LC). The staining intensity was enhanced by gentle trypsin pretreatment of the sections. Flow cytometric analysis of LC-enriched epidermal cells (EC) revealed that nearly all CD1a-bearing LC display anti-CD69 reactivity when tested briefly after termination of the enrichment procedure. Immunoprecipitation experiments showed that isolated LC specifically express a disulphide-linked dimer composed of 26/30kDa subunits that therefore slightly differs from the 28/32kDa CD69 complex described on activated T or natural killer (NK) cells. This difference is probably due to a different post-translational glycosylation pattern as evidenced by Endoglycosidase-F treatment of the immunoprecipitate disclosing the 24-kDa core protein of CD69. When freshly isolated LC-enriched EC were kept in culture, anti-CD69 reactivity gradually decreased but the addition of IFN-gamma to the culture medium sustained the CD69 expression on LC in vitro. These results strongly suggest that resident but not LC recovered from EC cultures bear CD69 moieties. It remains to be seen whether the expression of this antigen can be linked to (a) particular functional property (ies) of intraepidermal LC.

Antibodies, Monoclonal↗
PubMed1992

Fc epsilon RI mediates IgE binding to human epidermal Langerhans cells.

In a recent series of experiments, we observed that epidermal Langerhans cells (LC) of healthy, non-atopic individuals have the capacity of specifically binding monomeric serum or myeloma IgE. IgE-binding to LC could neither be prevented by pre-incubation of the cryostat sections with monoclonal antibodies (MoAb) against either Fc epsilon RII/CD23 or Fc gamma RII/CD32 nor by the addition of excess amounts of lactose, but could be entirely abrogated by pre-incubation with the anti-Fc epsilon RI MoAb 15-1. A direct testing of the anti-Fc epsilon RI MoAb 15-1 and 19-1 on cryostat sections in an indirect immuno-double-labeling technique showed that, in contrast to eight different anti-Fc epsilon RII/CD23 MoAb, these MoAb react with the majority of CD1a-bearing epidermal cells. At an ultrastructural level, 15-1 immunogold-labeling in the epidermis was confined to the surface of cells exhibiting Birbeck granules. In further experiments, we were able to amplify by polymerase chain reaction (PCR) technology transcripts for the alpha, beta, and gamma chains of Fc epsilon RI from LC-enriched epidermal cells and dermal cells, but not from LC-depleted epidermal cells. Transcripts for the mast cell enzyme tryptase were exclusively found in dermal cell-derived RNA preparations, thus excluding a contamination of the LC-enriched epidermal cell preparations by dermal mast cells. Collectively, these data show that epidermal LC, but not other epidermal cells, express Fc epsilon RI molecules.

Dermatitis, Atopic↗
PubMed1992

[Linear relations of brain pulse amplitude to mean intracranial pressure].

A catheter for intracranial pressure monitoring was introduced into the right lateral ventricle in 71 neurosurgical patients. In 63 patients (88.7%) a significant linear relationship was found between the cerebral pulse amplitude (PA) and the mean intracranial pressure (Pm). In 8 patients (11.3%) no linear relationship was established between PA and Pm. PA- and Pm-analyses performed subsequent to these compliance tests are discussed on the basis of the pathophysiology of the intracranial space.

Blood Pressure↗
PubMed1992

[Extending informative value of intracranial pressure measurement by cerebral pressure amplitudes (Pa)--analysis of average intracranial pressure (Pm)].

One aim of the intracranial pressure measurement is observing constantly patients with intracranial space-occupying factors and therefore to act diagnosticly and therapeutically correct at the right time. Through the continual registration of the intracranial pressure amplitude in relation to the medium intracranial pressure it is earlier possible to forecast intracranial pressure rise and to deal with this than with just the simple measurements of medium intracranial pressure. With 40 neurosurgical patients such examinations were undertaken after implantation of a ventricle catheter. The value of this method was proven during the continual observation of the patient.

Brain Injuries↗
PubMed1992

[Improved patient monitoring during intracranial pressure measurement by calculating a theoretical pressure-volume curve].

Patients with an acute "brain damage" where an intracranial pressure rise can be suspected due to the pathophysiological context are an indication for intracranial pressure measurement. For registrating the reduction of the intracranial reserve space before the rise of the medium pressure, volume-loads from the side-ventricles were undertaken with 54 neurosurgical patients. A better bedside monitoring is possible though the mathematical registration of those factors which indicate the size of the functional intracranial reserve space. With the calculated parameters of the reserve space (pressure-volume-index) a theoretical pressure-volume-curve was demonstrated.

Blood Pressure↗
PubMed1990

Physical activity and colon cancer: a case-referent study in Stockholm.

A population-based case-referent study on physical activity (during working and recreational hours) and colon cancer was performed in Stockholm in 1986-1988. The study included 1,081 subjects. Low physical activity was associated with an excess risk of colon (but not rectum) cancer for both men and women, showing a dose-response relationship with decreasing levels of physical activity. The effect was seen in the left colon (relative risk = 3.2, 95% confidence interval = 1.5-7.0) rather than in the right colon (relative risk = 1.1, 0.5-2.5). These results persisted after adjustment for year of birth, gender, body mass, intake of total energy, protein, total fat, dietary fibre, and browned meat surface.

Adenocarcinoma↗
PubMed1990

Diet, body mass and colorectal cancer: a case-referent study in Stockholm.

A population-based case-referent study on diet (total energy, protein, fat, dietary fiber), body mass and colorectal cancer was performed in Stockholm in 1986-1988. The study included 1,081 subjects. The relative risks (RR, with a 95% confidence interval, highest versus lowest quintile) for colon cancer were as follows: total energy (1.7, 1.0-3.0), protein (2.4, 1.5-4.0), total fat (2.2, 1.3-3.6), dietary fiber for men (0.5, 0.2-1.1), dietary fiber for women (1.2, 0.7-2.3) and body mass (2.0, 1.3-3.1). The relative risks for rectal cancer were: total energy (2.4, 1.2-4.7), protein (3.6, 2.0-6.4), total fat (2.5, 1.4-4.6), dietary fiber (0.5, 0.3-0.9), body mass for men (1.7, 0.7-4.0), and body mass for women (1.0, 0.5-1.9). Adjustment for physical activity, body mass (in the diet analysis), the above-mentioned dietary factors (in the body mass analysis), and browned meat surface had little or no influence on the results.

Adult↗
PubMed1990

Human epidermal T cells predominantly belong to the lineage expressing alpha/beta T cell receptor.

The epidermis of clinically normal-appearing human skin harbors a phenotypically heterogeneous population of T lymphocytes (TCs), the majority of which are CD2+/CD3+/CD5+ "memory" cells, but in an unactivated state, and express the TCR-alpha/beta. In contrast to murine skin, only a very minor subpopulation of CD3+ cells in the human epidermis bears the TCR-gamma/delta. Epidermal TCs primarily are distributed along the rete ridges in the basal keratinocyte layer and are often in close apposition to Langerhans cells (LCs). These TCs were propagated from epidermal cell suspensions after stimulation with TC activating agents (Con A, rIL-1, rIL-2), then evaluated for phenotypic features and TCR diversity. Similar to the in situ situation, most were CD4-/CD8+/TCR-alpha/beta+. In addition, two cultures contained TCR-gamma/delta+ cells; one of these determined to be an adherent CD4-/CD8+ population. Epidermal TCs were significantly (p less than 0.0001) more abundant in the sole than in the other body regions examined (i.e., 40 vs. 7 CD3+ cells/linear centimeter of epidermis) and seemed to have a particular affinity for the acrosyringial epithelium of eccrine sweat ducts. Moreover, the sole usually contained a greater number of CD8+ relative to CD4+ TCs, whereas the epidermal CD4/CD8 ratio in the trunk and extremities was quite variable, although the trend also was towards a slightly larger percentage of CD8+ cells. Collectively, our data suggest that the volar epidermis has a unique microenvironment which is responsible for both the higher density of TCs, preferentially CD8+, and lower number of LCs. This study has not only provided evidence for significant regional variability in the human epidermal TC population of normal skin, but also strengthens the concept for skin-associated lymphoid tissues (SALT), whereby memory TCs recirculate back to the epidermis and interact with resident antigen-presenting cells (i.e., LC).

Antibodies, Monoclonal↗
PubMed1990

Clinical appearances in severe ischaemic colitis. Case report.

Ischaemic colitis was not diagnosed until laparotomy in five cases. In two it was secondary to hypotension and multiple organ failure, in two it was atherosclerotic, and one had polycythemia vera. The diagnosis should always be considered in patients with abdominal distension--with or without diarrhoea and abdominal pain--so that treatment may be instituted before the onset of peritonitis.

Aged↗
PubMed1989

Induction of Fc epsilon R2/CD23 on human epidermal Langerhans cells by human recombinant interleukin 4 and gamma interferon.

Human rIL-4 and human rIFN-gamma are able to induce the expression of the low affinity receptor for IgE (Fc epsilon R2/CD23) on normal human epidermal Langerhans cells, whereas IL-2 and PMA have no effect. A synergistic effect is observed when both cytokines are combined. These receptors are synthesized de novo by the LC since cycloheximide completely inhibits the appearance of Fc epsilon R2/CD23. Fc epsilon R2/CD23+ LC may have a major role in the pathogenesis of atopic eczema, as well as in the regulation of IgE synthesis.

Antibodies, Monoclonal↗