Clinical Significance of CDH13 Promoter Methylation in Serum Samples from Patients with Bladder Transitional Cell Carcinoma

H-cadherin (CDH13; also known as T-cadherin), which functions as a tumour suppressor, is frequently silenced by promoter methylation in human cancers including bladder transitional cell carcinoma (TCC). This study investigated the clinical significance of methylation of the CDH13 gene promoter in serum from patients with bladder TCC. Methylation status of CDH13 in serum samples from 127 patients with primary bladder TCC and 41 healthy volunteers (controls) was examined by methylation-specific polymerase chain reaction. CDH13 methylation was found in 39 patients with bladder TCC (30.7%) but in no controls. CDH13 methylation was significantly associated with advanced tumour stage, high-grade tumour, large tumour size, tumour recurrence and poor prognosis. The results suggested that CDH13 methylation in serum may be a potential predictive biomarker for malignancy in bladder TCC, and an independent pre-therapeutic predictor of outcome. Demonstration of CDH13 methylation in serum may facilitate in the prediction of which patients require more aggressive additional post-operative systemic therapy.

Relationship between psychosocial factors and onset of multiple sclerosis

OBJECTIVE

The aim of this study was to investigate the influence of psychosocial variables on patients with multiple sclerosis (MS) and the relationship between these variables and the onset of MS.

BACKGROUND

The current evidence indicates that many types of psychosocial factors are involved in the development and relapse of MS, and it has been suggested that they could serve as predictors as well. So far, little has been reported on the effect of psychosocial factors on MS and the relationship between psychosocial factors and the onset of MS.

METHODS

Forty-one patients, 15 males and 26 females, average age 37.44 +/- 12.24 years (mean +/- SD), were evaluated by the Life Event Scale, Eysenck Personality Questionnaire, Social Support Revaluate Scale and Symptom Check List 90 and compared with 41 equivalent healthy control subjects, 15 males and 26 females, average age 36.38 +/- 12.84 years (mean +/- SD). Disease, demographic, psychosocial and lifestyle factors were measured at baseline. Patients with MS were first diagnosed by 3 neurologists according to the Poser (1983) MS diagnostic criteria.

RESULTS

Significant differences were found between the MS and the control group in their negative emotions and symptoms such as depression, anxiety, obsession, phobia, tense interpersonal relationship and somatization disorder. Significant differences were found between the two groups in the total number of negative life events, their family problems and the utilization of social support. The scores for various negative emotions in the MS group correlated positively with those for neuroticisms in personality type, and negatively with those for introverted and extroverted personality. Many kinds of negative emotions in the MS group correlated positively with the total number of life events, negative life events and family problems. Many kinds of negative emotions in the MS group correlated negatively with the utilization of social support.

CONCLUSION

The psychosocial factors are closely associated with MS onset and may play important roles in the development of the disease.

A study of the purine derivative AIT-082 in G93A SOD1 transgenic mice

AIT-082 is a purine derivative with neuroprotective and neurotrophic activity that is desirable in a candidate therapy for Amyotrophic Lateral Sclerosis. Consequently, we investigated the effect of AIT-082 in a transgenic mouse model of ALS. AIT-082 (0, 1, 3, 10, 30, 60, 100 mg/kg) was given to TgN(SOD1-G93A)1Gur transgenic mice from age 30 days until death. The age at onset of clinical signs of disease and the age at death were recorded for each animal. Disease progression was measured by the weekly average distance run in a running wheel. Analysis was made by the Kaplan Meier method with log rank statistics, log rank for trend and Cox regression. Neuropathological study of the brain, spinal cord, muscles and other organs was undertaken at death. In a second experiment we studied the effect of AIT-082 (30 mg/kg) at the onset of disease and during survival of transgenic G93A SOD1 mice, beginning dosing at different ages (20, 30, 40, 60, 80 days). Disease onset was mildly earlier (i.e. worse) at 1 and 10 mg/kg AIT-082 and mildly delayed at 30 mg/kg. This improvement did not reach the usual statistical significance. There was no difference in the age at death for any treatment dose. There was no difference in the neuropathology of treated and untreated G93A mice. However, there was an early improvement in the running wheel function at all tested doses. Using Cox regression, after adjustment for sex, the mice in the running wheels had slightly delayed onset of disease without change in survival and, after adjustment for exercise, the female mice had slightly improved survival. Consequently, AIT-082 would not be an attractive candidate for ALS clinical trials as monotherapy and justification for its use in combination therapy would require additional laboratory support. There was dissociation between the endpoints of disease progression (as judged by running wheel performance) and disease onset and survival. AIT-082 improved early running wheel performance yet led to accelerated late decline and had no impact on survival. It is possible that the drug facilitates early sprouting that leads to accelerated late decline.

Imaging matrix metalloproteinase expression in tumors

metastatic Matrix metalloproteinases (MMPs) are zinc-dependent secreted or transmembrane enzymes constituting a family of over 21 proteolytic members that are capable of selectively digesting a wide spectrum of both extracellular matrix (ECM) and nonmatrix proteins. MMPs play a critical role in tumor growth, angiogenesis, and metastatic processes. MMP inhibitors (MMPIs) have been extensively investigated as anti-tumor drugs, although the clinical trials thus far have been disappointing. In order to better understand the role of MMPs in cancer growth and metastasis, as well as improve the therapeutic efficacy of MMPIs, there is a need to develop new procedures to assess and/or monitor MMP activity in vivo. In addition to determining whether MMPs are present in tumors, it would be desirable to have an imaging agent that better probes other processes associated with MMP overproduction, including angiogenesis and the establishment of the growth of metastatic lesions in distant organ sites. In this paper we review the studies relating to the recent development of in vivo imaging of MMP expression. One of the purposes of this review is to discuss the current status of imaging MMP expression, which includes the types of tracers being developed and the types of imaging modalities available. Although imaging MMP expression is a relatively new area of research, the progress thus far is highly promising.

[Study on the improvement of process technology of L(+)-tartaric acid fermentation]

This work proposes an improved process technology of L(+)-tartaric acid produced by using cis-epoxysuccinates as the substrate for fermentation. The key to the question is to apply dipotassium cis-epoxysuccinate as the substrate instead of disodium cis-epoxysuccinate. As compared with the original process technology, the improved one has prominent advantages: 1. High yield of acid, increased by 20%-30% over the old one; 2. High rate of recovery, from about 60% to 80%; 3. One of the raw materials is cheaper, the KOH is expensive than NaOH, but half of the K kions could be used cyclically, and the varied products could be obtained easily; 4. The tough working procedure of filtration of fermented liquor could be evaded, the total working procedures might increase to some extent, but the cost of production will be reduced obviously, it is advantageous to industrial production.

Cell-specific targeting of caveolin-1 to caveolae, secretory vesicles, cytoplasm or mitochondria

In commonly used tissue culture cells, caveolin-1 is embedded in caveolae membranes. It appears to reach this location after being cotranslationally inserted into ER membranes, processed in the Golgi and shipped to the cell surface. We now report that caveolae are not the preferred location for caveolin-1 in all cell types. Skeletal muscle cells and keratinocytes target caveolin-1 to the cytosol while in exocrine and endocrine cells it accumulates in the secretory pathway. We also found that airway epithelial cells accumulate caveolin-1 in modified mitochondria. The cytosolic and the secreted forms appear to be incorporated into a soluble, lipid complex. We conclude that caveolin-1 can be targeted to a variety of intracellular destinations, which suggests a novel mechanism for the intracellular traffic of this protein.

Development of an in vitro model for assessing the in vivo stability of lanthanide chelates

An in vitro model was developed to evaluate the in vivo stability of lanthanide polyaminocarboxylate complexes. The ligand-to-metal ratios for the chelates EDTA, CDTA, DTPA, MA-DTPA (monoamide-DTPA) and DOTA with the lanthanides lanthanum, samarium, and lutetium were optimized to achieve > or = 98% complexation yield for the resultant radiolanthanide complexes. The exchange of the radiolanthanides from their EDTA, CDTA, DTPA, MA-DTPA and DOTA complexes with Ca(2+) was determined by in vitro adsorption and in vitro column studies using hydroxyapatite (HA), an in vitro bone model. In vitro serum stability of these radiolanthanide complexes was used as an additional indicator of in vivo stability, although the mechanism of instability in serum will be different than with bone. The in vitro studies were consistent with the expected findings that the smallest lanthanide (Lu) formed the most stable complexes. In vivo studies were done to validate the in vitro model. Biodistribution studies in normal CF-1 mice showed that in vivo stability of the complex (i.e., the more lanthanide remaining in complex form) could be assessed by a combination of the urinary, bone and liver uptake. For example, biodistribution studies demonstrate that high urinary excretion correlated with complex stability, while high liver plus bone uptake correlated with complex instability. The urinary excretion of the EDTA complexes decreased from (177)Lu to (140)La indicating a loss in stability in the direction of (140)La, consistent with the in vitro studies. The more stable a lanthanide complex is, the lower its exchange with HA in vitro will be, and the lower its combined bone plus liver uptake and higher its urinary excretion will be in vivo. This investigation indicates that the in vivo stability can be determined by a screening method that measures the degree of exchange from the lanthanide chelate with hydroxyapatite (HA) and its serum stability.

Determination of the critical pressure drop for filtration of super-compactible cakes

In accord with Darcy's law, the flow rate through a porous bed depends upon the pressure drop deltap(c). In general, increasing deltap(c) leads to increased values of flow rate and average percentage solids in filtration operations. When cakes become super-compactible, their behavior undergoes an unexpected change in which both the flow rate and the percentage solids reach maximum values and thereafter are unaffected by increasing deltap(c). The critical pressure drop deltap(c)R is defined as that value at which the flow rate reaches 90% of its ultimate value. When deltap(c) is greater than deltap(c)R and is doubled or tripled, the cake resistance approximately doubles or triples leaving the rate virtually unchanged. The super-compactibility problem is analyzed theoretically, and is verified by stepped pressure filtration experiments on different materials from Houston and Korea.

Oxygen tension limits nitric oxide synthesis by activated macrophages

Previous studies have established that constitutive calcium-dependent ('low-output') nitric oxide synthase (NOS) is regulated by oxygen tension. We have investigated the role of oxygen tension in the synthesis of NO by the 'high-output' calcium-independent NOS in activated macrophages. Hypoxia increased macrophage NOS gene expression in the presence of one additional activator, such as lipopolysaccharide or interferon-gamma, but not in the presence of both. Hypoxia markedly reduced the synthesis of NO by activated macrophages (as measured by accumulation of nitrite and citrulline), such that, at 1% oxygen tension, NO accumulation was reduced by 80-90%. The apparent K(m) for oxygen calculated from cells exposed to a range of oxygen tensions was found to be 10.8%, or 137 microM, O(2) This value is considerably higher than the oxygen tension in tissues, and is virtually identical to that reported recently for purified recombinant macrophage NOS. The decrease in NO synthesis did not appear to be due to diminished arginine or cofactor availability, since arginine transport and NO synthesis during recovery in normoxia were normal. Analysis of NO synthesis during hypoxia as a function of extracellular arginine indicated that an altered V(max), but not K(m)(Arg), accounted for the observed decrease in NO synthesis. We conclude that oxygen tension regulates the synthesis of NO in macrophages by a mechanism similar to that described previously for the calcium-dependent low-output NOS. Our data suggest that oxygen tension may be an important physiological regulator of macrophage NO synthesis in vivo.

Transport-dependent proteolysis of SREBP: relocation of site-1 protease from Golgi to ER obviates the need for SREBP transport to Golgi

Cholesterol homeostasis in animal cells is achieved by regulated cleavage of membrane-bound transcription factors, designated SREBPs. Proteolytic release of the active domains of SREBPs from membranes requires a sterol-sensing protein, SCAP, which forms a complex with SREBPs. In sterol-depleted cells, SCAP escorts SREBPs from ER to Golgi, where SREBPs are cleaved by Site-1 protease (S1P). Sterols block this transport and abolish cleavage. Relocating active S1P from Golgi to ER by treating cells with brefeldin A or by fusing the ER retention signal KDEL to S1P obviates the SCAP requirement and renders cleavage insensitive to sterols. Transport-dependent proteolysis may be a common mechanism to regulate the processing of membrane proteins.

Experience of urgent reconstruction of electrical injuries

Although there have been great advances in the treatment of electrical injuries in the last 20 years, the extremity loss ratio in electrical injuries remains at an unacceptably high level. The primary reason for this is the progressive tissue necrosis and enlargement of the necrosis in the wound. The goal in this study is to examine possible ways to break the necrotic malignancy circle and save the form and function of damaged extremities. As a result of systematic experimental and clinical research, a comprehensive urgent reconstruction alternative for electrical injuries has been proposed. The alternative includes the following principles: debriding the wound as early as possible after injury; preserving as much as possible the vital tissue structures, such as nerve, vessels, joints, tendons, and bone, even when they have undergone devitalization or local necrosis; transplanting these vital tissues during the first surgery if the functional reconstruction requires; nourishing the wound bed by covering with tissue flaps that have rich blood supply; improving flap survival by continuous irrigations with a compound medicine beneath the flaps for a 24- to 72-hour period after surgery; providing general treatment with vasoactive agents and antibiotics. This paper summarizes our experience of using this method in the treatment of 105 electrical injury patients (a total of 309 wounds) in the time period from 1 January 1986 to 31 December 1996. Satisfying results were obtained, with the extremity loss ratio decreasing to 7% as compared to 41.5% during the 10 years preceding 1984 at the same hospital. Thus, the urgent comprehensive reconstruction alternative presented here is an effective and workable method to manage electrical injuries.

Identification of caveolin-1 in lipoprotein particles secreted by exocrine cells

Caveolin-1 is a protein component (of relative molecular mass 22, 000) of the striated coat that decorates the cytoplasmic surface of caveolae membranes. Previous biochemical and molecular tests have indicated that caveolin-1 is an integral membrane protein that is co-translationally inserted into endoplasmic-reticulum membranes of fibroblast and epithelial cells such that its carboxy- and amino-terminal ends are in the cytoplasm. Here we identify caveolin-1 in the secretory pathway of exocrine cells. Secretion of caveolin-1 from pancreatic acinar cells and a transfected exocrine cell line, but not from Chinese hamster ovary cells, is stimulated by the secretagogues secretin, cholecystokinin and dexamethasone. The secreted caveolin-1 co-fractionates with apolipoproteins, indicating that it may be secreted in a complex with lipids.

Deprivation of endogenous brain-derived neurotrophic factor results in impairment of spatial learning and memory in adult rats

Brain-derived neurotrophic factor (BDNF) is abundantly expressed in the hippocampus and cerebral cortex and is involved in synaptic plasticity and long-term potentiation (LTP). The present study was under taken to investigate whether endogenous BDNF was required for spatial learning and memory in a rat model. Antibodies to BDNF (anti-BDNF, n=7) or control immunoglobulin G (control, n=6) were delivered into the rat brain continuously for 7 days with an osmotic pump. The rats were then subjected to a battery of behavioral tests. The results show that the average escape latencies in the BDNF antibody treated group were dramatically longer than those of the control (F=13.3, p<0.001). The rats treated with control IgG swam for a significantly longer distance in the P quadrant (where the escape plane had been placed) compared with the other three quadrants (p<0.05). In contrast, anti-BDNF-treated rats swam an equivalent distance in all four quadrants. The average percentage of swimming distance in the P quadrant by anti-BDNF-treated rats was much less than that by control IgG treated rats (p<0.001). These results suggest that endogenous BDNF is required for spatial learning and memory in adult rats.

Nitric oxide synthase neurons in different areas of normal aged and Alzheimer's brains

This study investigated the distribution of nitric oxide synthase-containing neurons in the cerebral cortex of individuals with Alzheimer's disease, and compared them with age-matched controls. Paraffin-embedded sections of the frontal (area 10), occipital (area 17) and entorhinal cortices (area 28), and hippocampal formation obtained from 13 autopsy cases were used in the study. Neurons expressing nitric oxide synthase messenger RNA and protein were identified, respectively, by in situ hybridization and immunohistochemistry. Optical densities of nitric oxide synthase-positive neurons were assessed in 50 randomly selected fields of each of the above regions of the cortices, in each case by microscopic photometry. In the frontal cortex of the Alzheimer group, while a decrease in the number of nitric oxide synthase-positive neurons was evident, the nitric oxide synthase neurons, on the other hand, showed an increased optical density in layers II-IV when compared with those of normal ageing. In the occipital cortices, no significant differences in optical density were recorded between the normal ageing and Alzheimer specimens. In the entorhinal cortex, the optical densities of nitric oxide synthase neurons were again similar between the Alzheimer and age-matched control groups. In the hippocampar formation itself, there was an increase of nitric oxide synthase staining in the Alzheimer patients. These results show that (i) nitric oxide synthase neurons are abundant in the human cortex, (ii) the distribution of nitric oxide synthase neurons differs between different cortical regions, and (iii) there are differences between normal ageing and Alzheimer patients in the frontal cortex and the hippocampus.

Upregulation of brain-derived neurotrophic factor and neuropeptide Y in the dorsal ascending sensory pathway following sciatic nerve injury in rat

An immunohistochemical study was undertaken to examine the changes of brain-derived neurotrophic factor (BDNF) and neuropeptide Y (NPY) in the nucleus gracilis of rats following sciatic nerve transection. The results showed that BDNF-immunoreactivity (-ir) in the gracile nucleus was significantly increased after the nerve injury. The upregulation was apparent 24 h after nerve lesion, remaining robust up to 56 days postlesion. The increase in BDNF-ir was blocked by hemisection of the spinal cord, or by dorsal rhizotomy ipsilateral to the lesion. NPY-ir changes were similar to those of BDNF-ir, but the onset was delayed by 7 days. No NPY-ir was detected in dorsal root ganglion (DRG) from normal animals. Following sciatic nerve lesion, most of the NPY-immunoreactive neurones were found to be colocalized with BDNF-immunoreactive neurones. Neutralization of endogenous BDNF with its antiserum had no effects on NPY-ir in either the gracile nucleus or DRG. These results indicate that neurones contributing to the dorsal ascending sensory pathway upregulate the expression of both BDNF and NPY in response to sciatic nerve injury.

Neurotransmitters, peptides, and neural cell adhesion molecules in the cortices of normal elderly humans and Alzheimer patients: a comparison

Immunocytochemical techniques was used to compare the proportion of neurons expressing various neurotransmitters (tyrosine hydroxylase, choline acetyltransferase and gamma-aminobutyric acid), neuropeptides (Leu-enkephalin and substance P) and neural cell adhesion molecules (NCAM) in the hippocampus, frontal (area 10) and occipital (area 17) cortices of neurologically normal elderly humans to that of age-matched Alzheimer disease (AD) patients. There was no difference in the proportion of GABAergic and cholinergic cells between the normal and AD groups in all three brain regions studied. However, the catecholaminergic cells in the frontal cortex of the AD patients revealed a significant decrease. The catecholaminergic cells present in the cortex were both neurons and astrocytes, as revealed by a double immunostaining of tyrosine hydroxylase and glial fibrillary acid protein (GFAP). Furthermore, the difference in the proportion of cells expressing Substance P and Leu-enkephalin was minimal between the two groups studied. Although there was little difference in the levels of NCAM in the occipital cortex and hippocampus of the two groups, there were significantly fewer positive NCAM neurons in the frontal cortex of AD than normal aging individuals.

cDNA cloning of mouse and human cholesterol 25-hydroxylases, polytopic membrane proteins that synthesize a potent oxysterol regulator of lipid metabolism

Oxysterols regulate the expression of genes involved in cholesterol and lipid metabolism and serve as intermediates in cholesterol catabolism. Among the most potent of regulatory oxysterols is 25-hydroxycholesterol, whose biosynthetic enzyme has not yet been isolated. Here, we report the cloning of cholesterol 25-hydroxylase cDNAs from the mouse and human. The encoded enzymes are polytopic membrane proteins of 298 and 272 amino acids, respectively, which contain clusters of histidine residues that are essential for catalytic activity. Unlike most other sterol hydroxylases, cholesterol 25-hydroxylase is not a cytochrome P450, but rather it is a member of a small family of enzymes that utilize diiron cofactors to catalyze the hydroxylation of hydrophobic substrates. The cholesterol 25-hydroxylase gene lacks introns, and in the human it is located on chromosome 10q23. The murine gene is expressed at low levels in multiple tissues. Expression of cholesterol 25-hydroxylase in transfected cells reduces the biosynthesis of cholesterol from acetate and suppresses the cleavage of sterol regulatory element binding protein-1 and -2. The data suggest that cholesterol 25-hydroxylase has the capacity to play an important role in regulating lipid metabolism by synthesizing a co-repressor that blocks sterol regulatory element binding protein processing and ultimately leads to inhibition of gene transcription.

Prognostic value of beta1,6-branched oligosaccharides in human colorectal carcinoma

Increase of beta1,6-branched oligosaccharides is possibly associated with tumor progression and lymph node metastasis. The aim of this study was to determine the prognostic value of beta1,6 branches in human colorectal carcinoma. Expression of beta1,6 branches was histochemically evaluated using the leukoagglutinating Phaseolus vulgaris lectin, PHA-L, in 92 clinically documented colorectal carcinomas, of which 31 had formed lymph node metastases. The follow-up time ranged between 4 and 14 years (median, 10.3 years). A PHA-L staining index (SI), taking into account staining intensity and its percentage of tumor cut surface area, was established. The carcinoma SI was highly associated with the disease-free survival (P = 0.004) and overall survival (P = 0.005). Patients with a carcinoma SI of >1, as compared to those with a SI of < or =1, were at significantly higher risk for tumor recurrence, with a shorter disease-free survival (hazard ratio = 2.59, P = 0.005) and significant higher risk of death with shorter overall survival (hazard ratio = 2.51, P = 0.007). The carcinoma SI was also associated with the presence of lymph node metastases. We conclude that PHA-L staining in human colorectal carcinoma sections provides an independent prognostic indicator for tumor recurrence and patient survival and is associated with the presence of lymph node metastases.

PYY-preferring receptor in the dorsal vagal complex and its involvement in PYY stimulation of gastric acid secretion in rats

1. Microinjection of peptide YY (PYY, 7-46 pmol) into the dorsal vagal complex (DVC) stimulated gastric acid secretion in urethane-anaesthetized rats. Using a variety of neuropeptide Y (NPY) and PYY derivatives, we characterized the pharmacological profile of the receptor mediating the acid secretory response to PYY. 2. [Pro34]rat(r)/porcine(p)PYY and [Pro34]human(h)PYY (23-117 pmol), microinjected unilaterally into the DVC resulted in a similar maximal increase in net acid secretion reaching 68+/-11 and 89+/-31 micromol 90 min(-1) respectively. 3. Rat/hNPY and pNPY (47 pmol) microinjected into the DVC induced a similar net gastric acid secretion (27+/-8 and 23+/-8 micromol 90 min(-1) respectively) and a higher dose (116 pmol) tended to reduce the response. 4. Pancreatic polypeptide (PP, 4-46 pmol), [Leu31,Pro34]r/hNPY (47 and 117 pmol) and the Y2 selective agonists, hPYY3-36, pNPY5-36 and PNPY13-36 (25-168 pmol) microinjected into the DVC failed to influence basal gastric acid secretion. 5. The rank order of potency of PYY > or = [Pro34]r/pPYY = [Pro34]hPYY> r/hNPY = pNPY to stimulate gastric acid secretion upon injection into the DVC and the ineffectiveness of PP, [Leu31,Pro34]NPY and C-terminal NPY/PYY fragments suggest that a PYY-preferring receptor subtype may be involved in mediating the stimulating effect.

Lectin-Gold Histochemistry on Paraffin and Lowicryl K4M Sections Using Biotin and Digoxigenin-Conjugated Lectins

A variety of staining reactions for the visualization of cellular and extracellular glycoconjugates at the light microscopic level are available that are based on the detection of carboxyl and sulfate groups or periodic acid reactive configurations (1,2). Starting in the late 1960s lectins have replaced many of these chemical staining reactions because of their high specificity for defined monoand oligosaccharidic sequences in both N- and o-glycosidic-linked oligosaccharide side-chains of glycoproteins and glycolipids. In order to be useful as histochemical reagents, lectins must be tagged with appropriate markers and those employed in immunocytochemistry have been used successfully (3-9) Horisberger and coworkers were the first to prepare lectins labeled with particles of colloidal gold and used them in scanning electron mrcroscopy (10) Subsequently, gold-labeled lectins were applied in transmission electron microscopy to study various aspects of cell surface expression and internalization of lectin-binding sites (5,8,11,12), as well as in postembedding labeling of Lowicryl K4M thin sections (13). Later, it was shown that gold-labeled lectins can be used to stain sections of paraffin-embedded tissues (14-16), as well as semithin sections of Epon (17) and Lowicryl K4M-embedded tissues (18,19), However, in order to achieve a visible pink staining, which is the natural color of particles of colloidal gold in transmitted visible light (20), highly concentrated lectin-gold complexes had to be used, thereby allowing the possibility of nonspecific staining. A major improvement resulted through the application of a photochemrcal silver reaction for signal amphfication (21-24), whrch permitted the use of lectins for light microscopy in concentrations as applied for electron microscopy (25,26).

Expression of beta 1,6 branched asparagine-linked oligosaccharides in non-mitotic and non-migratory cells of normal human and rat tissues

Malignant transformation of cells leads to the synthesis of large asparagine-linked oligosaccharides that exhibit a higher degree of beta 1,6 branching. In rodent and human tumor cell lines and certain human tumors, increased beta 1,6 branching of oligosaccharides has been shown to be associated with metastasis. In addition, this structural change occurs in glycoproteins of stimulated normal human lymphocytes. The leukoagglutinating Phaseolus vulgaris lectin (L-PHA) has a high affinity for tri- and tetraantennary beta 1,6 branches carrying oligosaccharides and has been widely used for the detection of such structures by histochemistry and blotting. We have analyzed a spectrum of normal human and rat tissues using a sensitive silver-intensified lectin-gold technique. Staining by L-PHA was detected in undifferentiated cells of germinative layers of the gastrointestinal and respiratory tract as well as testis. However, differentiated and non-mitotic epithelia in most organs showed strong lectin staining as well. Notable exceptions were the epithelium of the colon and resting mammary gland, which were unreactive with L-PHA. The histochemical studies were supplemented by lectin blotting, which showed the presence of diverse L-PHA-reactive glycoproteins in rat tissues. Our data may be of importance for the use of L-PHA in studies on human malignant tumors.

Terminal dUTP nick end labeling (TUNEL) positive cells in the different regions of the brain in normal aging and Alzheimer patients

This study investigated terminal dUTP nick-end labeling (TUNEL)-positive cells in the frontal, occipital, and hippocampal cortices of seven normal aging and four Alzheimer's patients. Significant increase in TUNEL-positive cells was observed in the frontal and hippocampal cortices of Alzheimer's patients when compared with controls. In the hippocampal cortex, only area CA4 demonstrated a significant increase of TUNEL-positive cells. Double staining of TUNEL-positive cells for glial fibrillary acidic protein revealed that < 13% of the TUNEL-positive nuclei belonged to astrocytes. The results of this study illustrated a differential pattern of cortical degeneration between normal aging and Alzheimer patients.

Colon carcinoma glycoproteins carrying alpha 2,6-linked sialic acid reactive with Sambucus nigra agglutinin are not constitutively expressed in normal human colon mucosa and are distinct from sialyl-Tn antigen

In human colon carcinoma, increased amounts of sialic acids have been found and correlated with tumor progression. Further, the degree of O-acetylation of sialic acid residues in normal mucosa is higher than in colon carcinoma. Thus, tumor-associated sialylated antigens may be constitutively expressed in O-acetylated form in normal mucosa unreactive with the respective monoclonal antibodies. We have earlier demonstrated a colon carcinoma-associated expression of alpha 2,6-linked sialic acid residues with the Sambucus nigra agglutinin (SNA). We report now that de-acetylation of normal and transitional colonic mucosa, in contrast to sialyl-Tn antigen, does not result in SNA binding. Further, the alpha 2,6-linked sialic acid recognized by SNA is distinct from that of sialyl-Tn antigen. This is confirmed by Northern blotting detecting transcripts for alpha 2,6 sialyltransferase of N-glycoproteins and measurement of activity for this sialyltransferase. Blot analysis by SNA of colon carcinoma cells revealed few reactive glycoproteins. Quantitative differences in lectin labeling and sialyltransferase activity were found in HCT116 colon carcinoma cell sub-lines. Our data suggest that SNA binding in human colon carcinoma is due to de novo expression of a specific sialic acid present on selected glycoproteins.