Modulation of skin cell functions by transforming growth factor-beta1 and ACTH after ultraviolet irradiation

A new method was developed for binding poly-(ethylene oxide) (PEO) to polymer surfaces that involves the use of electron beam irradiation in two steps. In the first, methacrylic acid was grafted and polymerized to a polymer surface, changing it from hydrophobic to hydrophilic. Exposure of this surface to aqueous PEO solutions resulted in strong hydrogen bonding of the PEO, which was covalently grafted in a second radiation step. The PEO grafts were stable; they could not be removed with extensive washing with water, soaking in basic solution, or gentle mechanical scraping. Both monolayers and multilayers of PEO were formed. The density of the monolayers were found to have little dependence on the molecular weight or concentration of the PEO solution; multilayers could be controlled by varying the viscosity of the PEO solution and the method of application. The PEO-grafted monolayers were tested for their ability to prevent protein adsorption of cytochrome-c, albumin, and fibronectin. Monolayers of star PEO were the most effective, at best showing a 60% decrease in adsorption from untreated controls. One million molecular wight linear PEO monolayers were almost as effective as star monolayers, and 35,000 g/mol linear PEO was bound too closely to the surface, owing to its small size, to have much impact in preventing protein adsorption. The reason for the continued protein adsorption was believed to be due to a close grafting of the PEO to the surface, as well as the grafted methacrylic acid chains being long enough to extend through the PEO monolayer, thus being accessible on the surface.     

Determination of the amino acid requirements for a protein hinge in triosephosphate isomerase

We have determined the sequence requirements for a protein hinge in triosephosphate isomerase. The codons encoding the hinge at the C-terminus of the active-site lid of triosephosphate isomerase were replaced with a genetic library of all possible 8,000 amino acid combinations. The most active of these 8,000 mutants were selected using in vivo complementation of a triosephosphate isomerase deficient strain of E. coli, DF502. Approximately 3% of the mutants complement DF502 with an activity that is above 70% of wild-type activity. The sequences of these hinge mutants reveal that the solutions to the hinge flexibility problem are varied. Moreover, these preferences are sequence dependent; that is, certain pairs occur frequently. They fall into six families of similar sequences. In addition to the hinge sequences expected on the basis of phylogenetic analysis, we selected three new families of 3-amino-acid hinges: X(A/S)(L/K/M), X(aromatic/beta-branched)(L/K), and XP(S/N). The absence of these hinge families in the more than 60 known species of triosephosphate isomerase suggests that during evolution, not all of sequence space is sampled, perhaps because there is no neutral mutation pathway to access the other families.     

Subclinical surface alterations of human pleura. A scanning electron microscopic study

Pleuritis or pleural effusion frequently develops in patients with pneumonia or heart failure. Most of these pleural changes regress without intrapleural intervention. The detailed mechanisms of the regression of the pleural changes in humans are not well documented. We studied the parietal pleura of nine patients with lung cancer and two patients with coronary artery disease by scanning electron microscopy (SEM). All patients had neither radiographic nor gross evidence of pleural disease but all had mixed surface alterations by SEM. Focal denudation of mesothelial cells was common. Deeper injuries exposed thick and thin interweaving collagen bundles. Patchy depositions of amorphous or crystallized fibrin covered normal and damaged pleural surfaces, frequently admixed with macrophages, red blood cells, and tissue debris. Reactive mesothelial cells appeared to proliferate over the fibrin. Our findings suggest that subclinical pleural alterations occur often in patients with pulmonary or cardiac diseases and that an intact pleural surface in those patients is restored mainly by the proliferation of reactive mesothelial cells.     

T cell vaccination induces T cell receptor Vbeta-specific Qa-1-restricted regulatory CD8(+) T cells

Vaccination of mice with activated autoantigen-reactive CD4(+) T cells (T cell vaccination, TCV) has been shown to induce protection from the subsequent induction of a variety of experimental autoimmune diseases, including experimental allergic encephalomyelitis (EAE). Although the mechanisms involved in TCV-mediated protection are not completely known, there is some evidence that TCV induces CD8(+) regulatory T cells that are specific for pathogenic CD4(+) T cells. Previously, we demonstrated that, after superantigen administration in vivo, CD8(+) T cells emerge that preferentially lyse and regulate activated autologous CD4(+) T cells in a T cell receptor (TCR) Vbeta-specific manner. This TCR Vbeta-specific regulation is not observed in beta2-microglobulin-deficient mice and is inhibited, in vitro, by antibody to Qa-1. We now show that similar Vbeta8-specific Qa-1-restricted CD8(+) T cells are also induced by TCV with activated CD4(+) Vbeta8(+) T cells. These CD8(+) T cells specifically lyse murine or human transfectants coexpressing Qa-1 and murine TCR Vbeta8. Further, CD8(+) T cell hybridoma clones generated from B10.PL mice vaccinated with a myelin basic protein-specific CD4(+)Vbeta8(+) T cell clone specifically recognize other CD4(+) T cells and T cell tumors that express Vbeta8 and the syngeneic Qa-1(a) but not the allogeneic Qa-1(b) molecule. Thus, Vbeta-specific Qa-1-restricted CD8(+) T cells are induced by activated CD4(+) T cells. We suggest that these CD8(+) T cells may function to specifically regulate activated CD4(+) T cells during immune responses.     

Nonsurgical infarctectomy in acute experimental myocardial infarction

This study examines whether a catheter mounted left intraventricular balloon may prevent left ventricular (LV) dysfunction following acute experimental myocardial infarction. In 10 anesthetized pigs, multiple coronary arterial ligations were applied around the apex of the heart. LV end-diastolic pressure (LVEDP), aortic flow (AF), and LV long and short axis fractional shortening (FS) were measured before and at 15 min intervals after ligations. At the 60th min after ligation, the LV long axis FS and AF decreased by 7.2 +/- 2.6% (p < 0.05) and 13.25 +/- 2.68% (p < 0.01), respectively, and the LVEDP increased by 4.3 +/- 1.1 mm Hg (p < 0.01) while no change was noted in the LV short axis FS. An intraventricular catheter mounted nonpulsating balloon was positioned over the endocardium of the infarcted area at the LV apex. Inflation of the nonpulsating balloon to an optimal volume, which was found to be equal to 8-10% of the LV end-diastolic volume, resulted in a reduction (by 3.8 +/- 1.2 mm Hg, p < 0.01) of the already increased LVEDP and in an increase (by 6.6 +/- 2.1%, p < 0.05) in the LV short axis FS while no statistically significant change was noted in the AF and LV long axis FS. It is concluded that an intraventricular catheter mounted balloon patch positioned over the endocardium of the infarcted area may ameliorate early LV dysfunction, possibly by interfering with the functional geometry of the LV contraction.     

Serum concentrations of soluble adhesion molecules in patients with colorectal cancer

The concentrations of the soluble adhesion molecules E-cadherin, E-selectin, intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) were investigated in 48 patients with colorectal cancer before treatment, and their relation to clinical, histological and routine laboratory parameters was examined. Data were collected on tumour stage at presentation, presence and sites of metastatic disease, tumour pathology and results of routine laboratory tests. Serum concentrations of ICAM-1 and VCAM-1 were significantly elevated in the patients with colorectal cancer in comparison with a group of healthy subjects (P < 0.00001). Levels of circulating ICAM-1 and VCAM-1 were increased both in patients with local and those with metastatic disease. Although elevated in some patients soluble E-cadherin and E-selectin concentrations were not significantly elevated compared with the control group (P = 0.71 and P = 0.052 respectively). The levels of circulating ICAM-1 were significantly correlated with those of VCAM-1 and E-selectin. A correlation was also found between the serum concentrations of E-selectin and ICAM-1 and alkaline phosphatase, total white cell count and platelet count. VCAM-1 was positively correlated with age and negatively with degree of tumour differentiation and haemoglobin concentration. The biological implications and possible clinical relevance of these findings are discussed.     

Measurement of secondary colony formation after 5 weeks in long-term cultures in patients with myelodysplastic syndrome

Pancytopenia is a frequent manifestation of myelodysplastic syndromes (MDS). In the presence of an empty bone marrow, clinical distinction from aplastic anemia may be difficult. The hypoplastic marrow morphology seen in some cases of MDS raises questions about etiologic and pathophysiologic relationships between aplastic anemia and MDS. The goal of our study was to compare the degree of the hematopoietic failure in these diseases at the level of the most immature progenitor and stem cells that can be measured in vitro. In a systemic, prospective fashion, we have studied bone marrow (n = 45) and peripheral blood (n = 33) of patients with MDS for the number of long-term culture initiating cells (LTC-IC) in comparison to 17 normal controls and patients with new, untreated aplastic anemia (46 marrow; 62 blood samples). Due to the low numbers of cells available for the analysis, formal limiting dilution analysis could not be performed, instead secondary colony-forming cells (CFC) after 5 weeks of LTBMC were measured. As the number of these cells is proportional to the input number of LTC-IC, the number of secondary CFC per 10(6) mononuclear cells (MNC) initiating the LTBMC can be used as a measure of the content of immature stem cells in bone marrow and peripheral blood. The MDS group consisted of 34 RA, three RARS, eight RAEB and two RAEB-T patients with mean absolute neutrophil values of 1992, 1413, 1441, and 380 per mm3, respectively. The diagnosis was established based on bone marrow morphology and results of cytogenetic studies. In comparison to controls (147 +/- 38/10(6) MNC), significantly decreased numbers of bone marrow secondary CFC were found in MDS: in patients with RA and RARS, 21 +/- 7 secondary CFC per 10(6) bone marrow MNC (P < 0.001); patients with RAEB and RAEB-T: 39 +/- 12 CFC per 10(6) marrow MNC (P < 0.001). In all groups tested, the decrease in peripheral blood secondary CFC numbers was consistently less pronounced. In MDS patients with hypocellular bone marrow, secondary CFC were lower but not significantly different in comparison to MDS with hypercellular marrow (18 +/- 6 vs 35 +/- 11; NS; hypoplastic bone marrow also was not associated with significantly lower neutrophil counts). However, in 24% of patients with MDS, bone marrow secondary CFC were within the normal range, while in the aplastic anemia group only one of the patients showed secondary CFC number within normal range. Bone marrow and blood secondary CFC numbers in hypoplastic RA were significantly higher than those in severe aplastic anemia 919 +/- 5 in bone marrow, P < 0.01; 7 +/- 2 in blood, P < 0.05). This trend was even more pronounced in hypoplastic RA with chromosomal abnormalities. However, no significant differences were found between the secondary CFC numbers in hypoplastic RA and moderate aplastic anemia. We concluded that, although the deficiency in the stem cell compartment is less severe in MDS than in aplastic anemia, depletion of early hematopoietic cells is an essential part of the pathophysiology in both diseases.     

Amino acid composition and biological value of rice proteins]

The study concerns the effect of angiotensin II when infused into the systemic and portal blood flow upon the general and renal haemodynamics in normal dogs and in hypertensive animals, as well as the effect of the operation of porto-caval transposition upon the course of renovascular hypertension. When peptide is infused, at a rate that causes a moderate pressor effect, into the systemic blood flow of normal animals, an antidiuretic and antinatriuretic effect is obtained, in hypertensive animals--an increase of diuresis, natriuresis and a less distinct pressor effect are obtained. When angiotensin II is infused into the portal flow, a less distinct pressor and renal effect is seen in animals with renovascular hypertension. The operation of porto-caval transposition of the vessels results in a hypotensive effect in the animals with renovascular hypertension.     

Tutor-student interaction in the operating theatre

This paper examines the view that productive teaching in the operating theatre requires a recognition of the unique set of factors which may influence the process of communication. For tutor-student interaction to occur in a productive manner, the tutor's behaviour will need to be modified to suit the demands of the other tasks in which both tutor and student are involved. The particular value of recognizing the role of nonverbal behaviours during interaction is discussed, with the use of specific examples related to the positioning of the tutor and student, and their use of facial expression, the eyes and voice.