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Biomedical subjects

W Tietz

Publications and source records attributed to W Tietz.

At least 19 recordsLinked to original sources
PubMed1998

CD4+ T cells migrate into inflamed skin only if they express ligands for E- and P-selectin.

Previous data suggested a role of endothelial selectins in skin homing of lymphocytes. In the current study, we have analyzed the expression and functional role of E-and P-selectin ligands on CD4+ T cells induced in vivo upon skin sensitization, using soluble selectin-Ig chimera and blocking Abs. Only low numbers of CD4+ cells expressing significant levels of E- or P-selectin ligands were present in s.c. lymph nodes of untreated mice (0.5-1.5% and 2-4%, respectively). Induction of a delayed-type hypersensitivity reaction increased the percentage of E-selectin-binding CD4+ cells in the draining lymph nodes up to 6 to 9% and that of P-selectin-binding cells up to 14%. The majority of E- and P-selectin-binding cells displayed an activated phenotype as judged by the increase in IL-2R, CD71, or cell size. The populations of E- and P-selectin-binding cells were largely overlapping; all E-selectin-binding cells also bound to P-selectin, whereas only a subfraction of P-selectin-binding cells reacted with E-selectin. Both E- and P-selectin-binding CD4+ cells, isolated by FACS, efficiently migrated into inflamed, but not normal skin, whereas P- or E-selectin ligand-negative CD4+ T cells did not. Abs against one of the two endothelial selectins partially inhibited the entry of isolated, ligand-positive cells, whereas a combination of Abs against both selectins almost completely abrogated skin homing. These data indicate that the expression of functional ligands for E- and for P-selectin is essential for homing of CD4+ T cells into the inflamed skin.

Animals↗
PubMed1997

P-selectin glycoprotein ligand-1 (PSGL-1) on T helper 1 but not on T helper 2 cells binds to P-selectin and supports migration into inflamed skin.

We have shown recently that mouse Th1 cells but not Th2 cells are selectively recruited into inflamed sites of a delayed-type hypersensitivity (DTH) reaction of the skin. This migration was blocked by monoclonal antibodies (mAb) against P- and E-selectin. Here we show that Th1 cells bind to P-selectin via the P-selectin glycoprotein ligand-1 (PSGL-1). This is the only glycoprotein ligand that was detectable by affinity isolation with a P-selectin-Ig fusion protein. Binding of Th1 cells to P-selectin, as analyzed by flow cytometry and in cell adhesion assays, was completely blocked by antibodies against PSGL-1. The same antibodies blocked partially the migration of Th1 cells into cutaneous DTH reactions. This blocking activity, in combination with that of a mAb against E-selectin, was additive. PSGL-1 on Th2 cells, although expressed at similar levels as on Th1 cells, did not support binding to P-selectin. Thus, the P-selectin-binding form of PSGL-1 distinguishes Th1 cells from Th2 cells. Furthermore, PSGL-1 is relevant for the entry of Th1 cells into inflamed areas of the skin. This is the first demonstration for the importance of PSGL-1 for mouse leukocyte recruitment in vivo.

Animals↗
PubMed1997

The migratory behavior of murine CD4+ cells of memory phenotype.

Lymphocyte differentiation is connected with profound alterations in the migratory pattern of lymphocytes. Whereas naive cells predominantly recirculate through lymphoid tissues, activated lymphocytes acquire an increased preference for immigration into non-lymphoid tissues and a reduced capacity for recirculation via high endothelial venules (HEV). A variety of data had indicated that memory-related subpopulations of cells in man and sheep, classified by the low expression of the CD45RA isotype, also lack the capacity to recirculate via HEV. However, recent data in the rat called these results into question. We therefore analyzed the migration properties of murine CD4+ T cell subpopulations defined by several markers used to distinguish memory from naive CD4+ cells in mice, namely CD45RB, L-selectin and CD44. Our data clearly show that the majority of putative memory cells expressing either low levels of CD45RB, low levels of L-selectin or high levels of CD44 display a strongly reduced capacity for direct entry into lymphoid tissues, including the spleen, from the blood stream. The accumulation in peripheral lymph nodes is further reduced by treatment with anti-L-selectin antibody, which blocks their entry via HEV. This indicates that memory CD4+ T cells are not excluded from crossing lymph node HEV, and that the numbers of cells entering the node via this route exceed the numbers entering via the afferent lymph, at least in the absence of local inflammation. Concomitantly, a strongly enhanced localization of cells of the memory phenotype is observed in lung and liver as compared with naive cells. Trafficking to specific sites such as skin or gut mucosa is not a prominent feature of the total population of memory cells. The trafficking to lung and liver and an increased ability to bind to dendritic cells, demonstrable in in vitro adhesion assays, suggest a more sessile phenotype of most memory cells. With respect to these properties, memory cells have a surprizing similarity to fully activated lymphocytes.

Animals↗
PubMed1985

The effect of potassium, calcium and magnesium concentration on insulin and glucagon secretion of the perfused dog pancreas.

The effect of different potassium, calcium and magnesium concentrations in the perfusate on the hormone secretion of the isolated dog pancreas was investigated. A potassium concentration above 15 mMol/l shortly stimulates the insulin and glucagon secretion. Potassium ions (greater than or equal to 15 mMol/l) completely inhibit the early phase of glucose-induced insulin release. At a low Ca2+-level (0.25 mMol/l) the glucose-stimulated insulin secretion is reduced to basal values. On the other hand, the glucagon release is stimulated under these conditions. An increase of magnesium ions from 1.0 mMol/l to 2.5-7.5 mMol/l strikingly inhibits insulin and glucagon release by approximately 50%, which is compensated for insulin by increasing the Ca2+-content of the medium. Perfusates for normothermic pancreas perfusion should contain electrolyte concentrations within the physiological range.

Animals↗
PubMed1984

[Hypothermic perfusion and cold storage of the dog pancreas].

The results of 18-hours of hypothermic pulsatile perfusion and 18-hours of cold storage of canine pancreas are compared. Both methods of preservation yield the same endocrine pancreas function. However preservation of pancreas by perfusion results in considerable oedema of the gland and high enzyme activity in the perfusate. Therefore, cold storage should be used for the preservation of pancreas.

Amylases↗
PubMed1984

[Oxygen requirements of the isolated dog pancreas].

This contribution reports about the oxygen requirement of the isolated perfused dog pancreas. A solution with the content of red blood corpuscles, a stroma-free hemoglobin solution or a perfusate--free from oxygen carriers--were applied. The oxygen requirement of the pancreas amounts to 0.59 ml/min . 100 g. The oxygen supply of the organ is possible with a flow of 0.50 ml/min . g and an oxygen partial pressure of 65 kPa (487.5 mmHg) also by means of a perfusate free from oxygen carriers.

Animals↗
PubMed1983

[Effect of potassium concentration of the perfusion solution on organ resistance of the perfused dog pancreas].

The influence of different potassium concentrations in the perfusate on the perfusion pressure of isolated dog pancreas is reported. A potassium concentration above 30 mmol/l leads both under hypothermic and normothermic conditions to an increase of the vascular resistance, That's why organs with a small blood flow should be perfused with solutions poor in potassium also in the initial perfusion.

Animals↗
PubMed1978

[Results of islet transplantation in diabetic dogs].

The influence of histocompatibility on islet transplantation in dogs was studied. Donors and hosts were chosen by help of the macrophage-electrophoresis-mobility test. By subtotal pancreatectomy and twice applying streptocotocin diabetes was successfully induced in recipient animals. Isolation of pancreating islets from the donor was done by means of the collagenase method combined with the Ficoll-gradient-separating technique. The grafting occurred via portal vein into the liver. Significant decrease of blood sugar during 10 weeks was observed in animals with good compatibility. This effect lasted only 14 days in cases of bad compatibility. Concentrations of insulin in the portal vein and superior caval vein 4 weeks after grafting was lower in cases with high-grade histoincompatibility. The duration of functioning of transplanted islets depends on the histocompatibility.

Animals↗
PubMed1977

Family sequelae after a child's death due to cancer.

In a small study assessing the psychologic sequelae on disadvantaged families after a child's death from cancer, a high incidence of psychologic problems was found. The implication is that the coping mechanisms failed partially as a result of inadequate anticipatory griefing.

Adaptation, Psychological↗
PubMed1976

[Transplantation of isolated islets of Langerhans into the liver of diabetic dogs (author's transl)].

Isolated islets of Langerhans were transplanted through the portal vein in the liver of 8 diabetic dogs; In 4 dogs a homologous transplantation was performed and another group of four dogs received isolated islets from their sisters or brothers. In both groups, there was an immediate effect on the blood glucose level. After pancreatectomy and injection of Alloxan the blood glucose rose to between 350 and 420 mg per 100 ml and after islet implantation the blood glucose decreased between 80 to 160 mg per 100 ml. The iv GTT'S were after islet implantation clear better than in the diabetic control animals. These results could maintained in the recipients with homologues islets over a period of 6 to 8 weeks and in the other group of dogs over a period of 6 to 12 months. We were able to show, that the islet implantation in the liver of diabetic dogs did not disturb the microscopic architecture of the liver. No signs of portal hypertension, hepatic congestion and embolism were found.

Animals↗
PubMed1975

The pediatrician and the dying child. "Physician, know thyself".

To deal with problems aroused in professional medical staff working with fatally ill children, a team of psychiatrics and oncologists not only deals with the problems of the children and their families, but also with problems of the medical staff themselves. Psychotherapy to the medical staff is offered only indirectly. The overriding difficulty which prevents the medical staff from maintaining role-appearance behavior is dealing with the theme of death. Often this is the hidden agenda behind a facade of other presenting problems. At times, the medical staff may be unable to deal with their own anger when conforted by demanding patients or hostile parents. At other times, medical staff will overidentify with the patient resulting in inappropriate role behavior. When medical results are poor despite good medical care, staff may feel inappropriately guilty. These issues can be dealt with means of a weekly mental health conference with the focus on the patient.

Adolescent↗
PubMed1975

Relationship of psychopathology to death in asthmatic adolescents.

With the help of three illustrative cases, all of whom died during an acute asthmatic attack, it is proposed that patients with severe psychopathology who also have asthma are particularly susceptible to the more serious complications of asthma. This is related to the circular reactions to anxiety and the patient's incapacity to cope with it. Often these patients are either unusually sensitive to the pharmacological agents used in the medical regime, or they overmedicate themselves. At the same time the reactions of the family and medical staff tend to increase anxiety in these patients. This finally leads to psychological decompensation, making medical treatment extremely difficult. Some therapeutic interventions in dealing with this problem have been suggested. These include the development of an asthma team which can provide supportive psychotherapy to high risk patients.

Acute Disease↗