Quantitative immunochemistry of endothelial cells in cutaneous tissue

In vivo endothelial cell exploration in human pathology has been limited by the lack of a suitable procedure for quantification of endothelial molecule expression. The objective of the present study was the development of a precise, simple and rapid image analysis method to quantify dermis endothelial cells and associated molecules. Cutaneous tissue sections were labelled by immunoperoxidase procedure using a monoclonal anti-von Willebrand factor (vWF) antibody, which identifies endothelial cells. The image analysis programme was tested to quantify final reaction deposit (DAB) with reference to different anti-vWF antibody concentrations. The entire biopsy section was acquired, field by field. Analysis was restricted to three dermis zones geodesically defined from epidermis. Optical density and area measurements were performed in whole area and in positive areas. This work demonstrated the feasibility of endothelial cell study assisted by image analysis. Surface labelled by anti-vWF antibody at saturating concentration may be considered as an endothelial reference surface, and thus may be useful for future quantification of other endothelial molecules.

Using oligonucleotide probe arrays to access genetic diversity

As the Human Genome Project and related efforts identify and determine the DNA sequences of human genes, it is important that highly reliable and efficient mechanisms are found to access individual genetic variation. It is only through a greater understanding of genetic diversity that the true benefit of the Human Genome Project will be realized. One approach, hybridization to high-density arrays of oligonucleotides, is a fast and effective means of accessing this genetic variation. Light-directed chemical synthesis has been used to generate miniaturized, high-density arrays of oligonucleotide probes. Application-specific oligonucleotide probe array designs have been developed for the rapid screening of characterized genes. Dedicated instrumentation and software have been developed for array hybridization, fluorescence detection and data acquisition and analysis. In a specific and challenging application, oligonucleotide probe arrays have been used to screen the reverse transcriptase and protease genes of the highly polymorphic HIV-1 genome to explore genetic diversity and detect mutations conferring resistance to antiviral drugs. Results from this application strongly suggest that oligonucleotide probe arrays will be a powerful tool for rapid investigations in sequence checking, pathogen detection, expression monitoring and DNA molecular recognition.

Landmark-driven fundus perimetry using the scanning laser ophthalmoscope

PURPOSE

To present a new method of performing scanning laser ophthalmoscope perimetry that compensates for eye movements so that the correct retinal location is tested even if fixation changes. This allows for accurate testing of patients with central scotomas and for repeating testing longitudinally at the same retinal locations even if central fixation is lost.

METHODS

The operator views the retina and selects a retinal landmark, such as a vessel bifurcation, that can be identified easily. A testing strategy is preselected, and the computer saves the landmark and stimulus coordinates. To present each stimulus, the operator positions a cursor over the retinal landmark, and the computer adjusts the site of presentation of the stimulus for any change in landmark position caused by an eye movement. At the conclusion of the testing, the results are displayed in the proper retinal location on a fundus image.

RESULTS

Sixty-seven eyes with macular disease were tested with the landmark-driven method, using the same preplanned strategy for each eye for both a bright and a dim stimulus. There was a low rate of inconsistent points (seen with dim but not bright stimuli), and virtually all of these bordered a dense scotoma. Those eyes with more inconsistent points had a significantly greater percentage of dense scotoma points and significantly lower visual acuity. The technique significantly corrected error in retinal localization resulting from large eye movement. There is no significant rotation or magnification change during the procedure, so specifying the change in location of one landmark is sufficient to describe movement of the retina. The technique is rapid and easy to administer to elderly patients and to children.

CONCLUSIONS

This technique allows for accurate and repeatable measures of retinal sensitivity in specific locations. It is useful in following change over time. It can be developed further to allow for fully automated, retinally correct testing.

Experimental study using a direct current electrical field to promote peripheral nerve regeneration

A direct current (DC) electrical field was used to stimulate transected and sutured rat sciatic nerve. Electrophysiologic, morphometric, and functional assessments were carried out on days 10, 20, 30, and 60 postoperatively. The results showed that the electrophysiologic index, the diameter and myelin-sheath thickness of regenerating nerve fibers, the sciatic functional index (SFI), and the strength of the triceps surae muscle in the experimental group were much better than those in the control group. This indicated that DC electrical stimulation could effectively promote peripheral nerve regeneration and produce positive effects after 3 weeks, and that the stimulator was not rejected by the host for a relatively long period of time.

Application of sciatic functional index in nerve functional assessment

In order to confirm the reliability of the sciatic functional index (SFI) in the rat, SFI, muscle strength, electrophysiological, and morphometric assessments were carried out from the 10th day to the sixth month after nerve injury or repair. The results showed that the SFI has a positive correlation with all tested indices of muscle strength, electrophysiology, and morphology (r = 0.925-0.996, P < 0.01 or P < 0.001). These results indicate that the SFI is a reliable index for evaluating rat sciatic nerve regeneration and can be widely used.

Expression of adhesion molecules in endothelial cells during allogeneic bone marrow transplantation

Endothelial cell activation during allogeneic bone marrow transplantation, mainly in acute graft-versus-host disease (aGvHD) was studied in 23 recipients and 5 controls using anti-von Willebrand factor (vWF) antibody, antibodies to endothelial leukocyte adhesion molecule-1 (ELAM-1), vascular cell adhesion molecule-1 (VCAM-1) and intercellular adhesion molecule-1 (ICAM-1), and anti-HLA-DQ antibody, by immunohistological staining of skin. vWF extravasation, ELAM-1 and VCAM-1 expression were present in most recipients with a cutaneous rash which was confirmed as an aGvHD by histological examination (documented aGvHD) (p = 0.005 for vWF extravasation and ELAM-1 expression and p = 0.03 for VCAM-1 expression in comparison with the controls). In recipients with a rash, the cases displaying vWF extravasation and ELAM-1 expression were significantly more numerous in those with a documented aGvHD than in those without histological features of aGvHD (p = 0.01). vWF extravasation and ELAM-1 occurred concomitantly (p < 0.01). This study demonstrates that, during the course of skin aGvHD following bone marrow transplantation, there is transient expression of ELAM-1 and VCAM-1 by endothelial cells and simultaneous vWF extravasation, indicating an intense inflammation with endothelial cell participation.

Heterogeneity of neoplastic and reactive cell proliferation in non-Hodgkin's lymphomas linked to patient survival

This study was undertaken to determine the characteristics of the proliferation of malignant and reactive cells in non-Hodgkin's lymphoma (NHL). Cell kinetics were studied in 76 previously untreated cases of NHL by flow cytometry after a double labeling of membrane antigen and DNA. Results were analyzed according to clinical and biologic characteristics of the patients. In B-cell NHL, percentages of B and T cells in S-phase were strongly linked (r = .82). The level of proliferation of malignant B cells and reactive T cells was significantly higher in aggressive lymphomas, compared with low grade, diffuse small cleaved cell NHL or reactive lymph nodes (P < .001). The percentages of malignant B cells in S-phase were lower when reactive T cells were more numerous (n = 59, r = -.264, P < .05), particularly in high-grade NHL (n = 16, r = -.78, P < .001). In the whole population of patients, survival was longer when the percentage of cells in S-phase (n1 = 38, n2 = 33) or S+G2 + mitosis (M) (n1 = 36, n2 = 35) was less than 3.2% and 7.25%, respectively (P < .005). When considering only B-cell NHL, survival was longer when the percentage of B cells in S-phase was less than 4.5% (n1 = 31, n2 = 28, P < .04). Among the slowly proliferative groups of lymphomas, this prognostic value was retained when S-phase value was less than 1% (n1 = 16, n2 = 13, P < .002). Furthermore, prognosis was better when the percentage of T cells in S-phase was less than 2.75% (n1 = 30, n2 = 29, P < .01) or when reactive CD4-positive T cells were more than 14.5% (n1 = 24, n2 = 24, P < .04). This result remained true in the group of highly proliferative lymphomas. These results illustrate the complexity of the interactions between malignant and reactive cells in NHL, with possible opposite effects on tumor cell growth.

Delivery of recombinant gene products with microencapsulated cells in vivo

If established cultured cell lines genetically modified to secrete desired gene products could be implanted in different allogeneic recipients without immune rejection, novel gene products would be delivered more cost effectively. We tested this strategy by encapsulating mouse Ltk- cells transfected with the human growth hormone (hGH) gene in immunoprotective perm-selective alginate microcapsules. Allogeneic mice implanted with these microcapsules demonstrated hGH in their circulation (0.1-1.5 ng/ml serum) within the first 2 weeks. Control mice implanted with only the transfected cells without microcapsules did not demonstrate significant levels of circulating hGH. By about 3 weeks, antibodies against hGH developed in the microcapsule-implanted mice. The immune response was detected only against the hGH and no other secretory products from the transfected cells. The antibody titer continued to escalate for more than three months, thus demonstrating indirectly the continued delivery of the growth hormone. The persistent expression of the transgene and survival of the transfected cells were verified when the microcapsules were retrieved periodically to demonstrate that the encapsulated cells remained viable, proliferative, and productive of hGH even by 78-111 days. In conclusion, delivering gene products with genetically modified allogeneic cells in vivo has been shown feasible for prolonged periods. This technology should have potential applications in somatic gene therapy and in treatment of other somatic diseases.

Metachromatic leukodystrophy: multiple nonfunctional and pseudodeficiency alleles in a pedigree: problems with diagnosis and counseling

Metachromatic leukodystrophy is due to deficient activity of arylsulfatase A, an enzyme important in myelin catabolism. The deficiency can be caused by different point mutations in the gene coding for arylsulfatase A (nonfunctional alleles). In addition, certain mutations result in low levels of enzyme activity detectable with artificial substrates in vitro but no clinical dysfunction (pseudodeficiency alleles). The described family has various combinations of normal, nonfunctional, and pseudodeficiency alleles that presented diagnostic and counseling dilemmas which were resolved at the genomic level. We find no evidence that compound heterozygote individuals have subclinical involvement of the nervous system. We report the clinical, pathological, electrophysiological, imaging, biochemical, and genetic data of this family and discuss the difficulties in analyzing such pedigrees.

Complications in the genotypic molecular diagnosis of pseudo arylsulfatase A deficiency

Metachromatic leukodystrophy (MLD) is a severe neurodegenerative disease associated with deficient arylsulfatase A activity. Biochemical confirmation of this disorder has been complicated by a clinically normal but enzymatically deficient variant, pseudo arylsulfatase-A deficiency (PD). The PD mutation is associated with two A-->G transitions in the arylsulfatase A gene. They can be detected simultaneously with a recently developed 3'-mismatch polymerase chain reaction, hence providing a rapid method for genotypic identification and resolving ambiguities of carrier identification based solely on enzyme analyses. However, we now report further genotypic complexities in the molecular diagnosis of PD due to the occurrence of another variant in which only one of the two A-->G mutations of the PD allele was present. This variant confers reduced but readily detectable enzyme activity and behaves as a silent allele in the 3'-mismatch polymerase chain reaction, thus leading to conflicting and erroneous genotype assignments in a family in which both variants and MLD co-exist. The inconsistency was resolved after pedigree validation and further molecular analyses in which the two A-->G mutations were assayed separately with allele-specific oligonucleotides. Because arylsulfatase A analysis is one of the most commonly requested lysosomal enzyme assays and the PD mutant allele frequency is high in the general population, complexities as described in this family may be a recurrent problem that can be solved only with combined enzymatic and detailed molecular analyses.

DNA adducts in model systems and humans

The etiology of chemically induced cancer is thought to involve the covalent binding of carcinogens to DNA (adducts) leading to mutations in oncogenes or tumor suppressor genes, and ultimately to tumors. Thus, the DNA-carcinogen adduct has been used as a measurable biochemical endpoint in laboratory studies designed to assess carcinogen exposure, carcinogen metabolism, mutagenesis, and tumorigenesis. Unfortunately, the significance of adducts in the etiology of human cancer is still unclear. This is partially due to the difficulty detecting adducts at carcinogen exposures relevant to humans, which are often orders of magnitude lower than animal model exposures. The relationship between adducts and higher biological effects is also not known at low doses. We have been assessing the DNA damage caused by exposure to heterocyclic amine carcinogens in the diet. Using the technique of 32P-postlabeling in combination with accelerator mass spectrometry, we have determined that DNA adduction in rodents decreases linearly with decreasing dose from the high doses used in typical cancer bioassays to the low doses relevant to human exposures. For a given tissue, adduct levels are correlated with dose, but the level of DNA modification by carcinogens is tissue-specific and does not completely correlate with tumor site. This lack of correlation may be due to differences in adduct formation and repair rates among tissues. Comparison of carcinogen metabolism routes between rodents and humans also indicates that species differences could influence the amount and type of damage resulting from exposure to these carcinogens. The use of model systems to study dosimetry, species differences in adduction, and role of adducts in mutation will ultimately lead to a better understanding of the significance of adducts in human disease. This should eventually allow the use of adducts as biomarkers for estimating carcinogen exposure and individual susceptibility.

Effects of calcium on recombinant bovine chromogranin A

Bovine chromogranin A, the acidic calcium-binding protein characteristic of endocrine secretory vesicles, has been expressed in Escherichia coli using the pET3a vector system under T7 polymerase control. The expressed protein is located in the bacterial cytosol and can be purified from bacterial proteins by a heat treatment step, followed by gel filtration, anion-exchange, and reversed-phase chromatography. The purified recombinant chromogranin A has an apparent M(r) of ca. 72,000 by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, in spite of its 432-amino acid polypeptide chain, consistent with observations on natural chromogranin A. The primary structure has been confirmed by mass spectral analysis of tryptic peptides, by Edman degradation of the intact protein, and by immunoreactivity with sequence-specific antibodies. Analysis by circular dichroism spectroscopy shows pH- and concentration-dependent spectra. The spectra are Ca2(+)-dependent from 5 to 40 microM.

Fate and distribution of 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine in mice at a human dietary equivalent dose

2-Amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) is a heterocyclic amine rodent carcinogen that is found at the ppb level in cooked meat. Most laboratory studies are at 10(4)-10(7)-fold greater concentrations than actual ingested human doses. We report the first study of the bioavailability and fate of this heterocyclic amine at a human dietary equivalent dose using the high sensitivity offered by accelerator mass spectrometry. [2-14C]PhIP was administered to C57BL/6 male mice (41 ng/kg) by gavage. Tissues and excreta were collected over the subsequent 96 h. One hundred % of the administered dose was excreted in urine (90%) and feces (10%) over the length of the study. Absorption of the radiocarbon-tagged PhIP from the gastrointestinal tract was rapid, with radiocarbon levels peaking in the whole blood and urine within 1 h of exposure. Fecal 14C levels peaked at 12 h. Tissue levels peaked by 3 h with the highest concentrations of radiolabel in the intestine, stomach, and liver, followed by the kidney, pancreas, lung, and spleen. Low levels of 14C from PhIP (0.01-0.04% of the administered dose) could be detected in the tissues 48-96 h after exposure, possibly due to covalent binding to protein or DNA. The calculated half-life of PhIP at this dose was 1.14 h. This study is the first example of how accelerator mass spectrometry can be used to gather biological information about carcinogenic compounds at environmental levels of exposure.

Apoptosis and DNA fragmentation precede TNF-induced cytolysis in U937 cells

The hypothesis that activation of apoptosis and DNA fragmentation is involved in TNF-mediated cytolysis of U937 tumor cells was investigated. Morphological, biochemical, and kinetic criteria established that TNF activates apoptosis as opposed to necrosis. Within 2-3 h of exposure to TNF, U937 underwent the morphological alterations characteristic of apoptosis. This was accompanied by cleavage of DNA into multiples of nucleosome size fragments. Both of these events occurred 1-2 h prior to cell death as defined by trypan blue exclusion or 51Cr release. DNA fragmentation was not a non-specific result of cell death since U937 cells lysed under hypotonic conditions did not release DNA fragments. The percentage of cells undergoing apoptosis depended on the concentration of TNF and was augmented by the addition of cycloheximide. A TNF-resistant variant derived from U937 did not undergo apoptosis in response to TNF, even in the presence of cycloheximide. Furthermore, TNF could still activate NFkB in this variant, suggesting that this pathway is not involved in TNF-mediated cytotoxicity. Two agents known to inhibit TNF-mediated cytotoxicity, ZnSO4 and 3-aminobenzamide, were shown to inhibit TNF-induced apoptosis. Taken altogether, these data support the hypothesis that activation of apoptosis is at least one essential step in the TNF lytic pathway in the U937 model system.

[Relationship between height, collagen metabolism, hair zinc and excessive fluoride intake]

After eliminating confounding factors, the study was made on the relationship between height, collagen metabolism, hair zinc and excessive fluoride intake. 140 schoolchildren aged 12-13 years born and reared in endemic fluorosis areas were surveyed. The results were as follows: 1. The average height of children with dental fluorosis III degree (DF III degree) was appreciably smaller than that of children without dental fluorosis. Among children with excessive fluoride intake, a negative correlation between the height and fluoride level in staple foods was seen. 2. The more the fluoride ingested, the higher the urinary THP excreted, showing that fluoride intoxication interfered with the collagen metabolism. 3. Among children with excessive fluoride intake, the height showed negative correlation with urinary THP/Cr, suggesting that the effect of fluoride on collagen metabolism indicated the mechanism of height retardation. 4. As compared to control group with the excessive fluoride intake but without dental fluorosis group, there was a significant reduction in hair zinc in group with DF III degree, suggesting that the zinc in the body decreased because of zinc metabolism disturbance by excessive fluoride intake. But among cases with excessive fluoride intake, no appreciable correlation between hair zinc and height was found. Therefore, it could not be confirmed that the effect of fluoride on zinc metabolism affected the height development.

[Protective effects of gypenosides on experimental myocardial infarction]

In the model of myocardial infarction produced by occlusion of left anterior descending coronary artery (LAD) in rabbit, gypenosides (GP 100 but not 50 mg/kg, ip) reduced myocardial infarct size and decreased serum free fatty acid (FFA). In rat model of myocardial infarction, GP and the fractions of GP of non ginsenosides (FGNG) both in dose of 100 mg/kg, ip, protected significantly myocardial superoxide dismutase (SOD) activity and decreased the myocardial malondialdehyde (MDA). The results indicate that the protective effect of GP on myocardial infarction may be correlated with its prevention of myocardial lipid peroxidation, and attributed to the amelioration of FFA metabolic deterioration.

T cell determinants of myelin basic protein include a unique encephalitogenic I-E-restricted epitope for Lewis rats

The major encephalitogenic epitope for Lewis rats is the 72-89 sequence of guinea pig basic protein (GP-BP) or rat basic protein (Rt-BP). T cells responsive to this epitope are I-A restricted and preferentially express the V alpha 2:V beta 8 gene combination in their TCR. In this work, we describe for the first time the delayed appearance of T cells specific for additional discrete determinant of BP, the nonencephalitogenic 55-68 sequence of GP-BP restricted by I-A, and the encephalitogenic 87-99 sequence of Rt-BP restricted by I-E. The TCR V alpha 2:V beta 8 gene combination was expressed by both encephalitogenic GP-BP S72-89 and Rt-BP S87-99 T cell specificities but not by GP-BP 44-68-specific T cells. This is the first demonstration of I-E-restricted encephalitogenic T cells in Lewis rats and supports the conclusion that the I-E class II locus is involved in autoimmune diseases.

Major outer membrane proteins unique to reproductive cells of Hyphomonas jannaschiana

Separation on the basis of molecular weight resolved three proteins specific to the swarmer cell of Hyphomonas jannaschiana. In the reproductive cell, 4 major proteins were identified as cytoplasmic and 10 were identified as envelope. Of these envelope proteins, one was common to both the inner and outer membranes, four were common to the inner membrane, and five were common to the outer membrane. Four of these outer membrane proteins were specific to the reproductive cell, and two of these proteins, with apparent molecular weights of 116,000 and 29,000, constituted 19% of the total cell protein and 54% of the outer membrane protein.

Both rat and mouse T cell receptors specific for the encephalitogenic determinant of myelin basic protein use similar V alpha and V beta chain genes even though the major histocompatibility complex and encephalitogenic determinants being recognized are different

Prospects for specific immune intervention in T cell-mediated autoimmune disease via anti-idiotypic regulation depend on the degree of diversity of the responder cell antigen receptor repertoire. A highly heterogenous response against self epitopes offers little chance for such regulation. We report here that the Lewis rat autoimmune disease experimental allergic encephalomyelitis, generally considered to be a model of human multiple sclerosis, is caused by T cells that use a limited set of TCR V genes. We have cloned the rat TCR alpha and beta chain cDNAs from the Lewis rat x mouse T cell hybridoma 510, which retains the rat specificity for the encephalitogenic determinant of myelin basic protein (MBP). Using Northern blot analysis of T cell RNA with the cloned V region probes, we have found a specific, and near perfect, correlation between expression of TCR message hybridizing to the V alpha 510 and VB510 probes and specificity for the encephalitogenic determinant of MBP in both T cell hybridomas and encephalitogenic T cell clones. This restricted V gene usage provides a basis for observed idiotypic regulation of auto-reactive T cells, and possible therapy for autoimmune disease. A curious and unexplained observation is that the Lewis rat V alpha/V beta combination that dominates the encephalitogenic response to the 68-88 peptide of MBP is precisely the same V alpha/V beta combination used by the B10.PL mouse response to the encephalitogenic response to the 1-9 peptide of MBP.