Structure, function, and pathology of proteoglycans and glycosaminoglycans in the urinary tract

The roles of glycosaminoglycans and proteoglycans in the physiology of the urinary tract are reviewed. The structures of proteoglycans and glycosaminoglycans are reviewed together with their role in control of epithelial differentiation through stromal-epithelial interactions and as modulators of cytokines. Heparan sulfate proteoglycans appear to be important in maintaining selectivity of the kidney tubular basement membrane, and the majority of the glycosaminoglycan found in the urine appears to come from the upper tract. Evidence suggesting that a dense layer of glycosaminoglycans on the urothelial surface is important to maintaining urothelial impermeability is reviewed and new data showing a high density of proteoglycans on the lumenal surface of the urothelium is presented. The role of this layer in maintaining antibacterial adherence and impermeability was discussed together with data suggesting that failure of this layer is an etiologic factor in interstitial cystitis. A model of the bladder surface is also presented to illustrate the role of proteoglycans and exogenous glycosaminoglycans in the defenses of normal bladder lumen and the failure of these defenses in the interstitial cystitis bladder.

Bladder cancer risk assessment with quantitative fluorescence image analysis of tumor markers in exfoliated bladder cells

BACKGROUND

The detection of potentially highly curable low-grade bladder cancers by noninvasive techniques remains an unsolved problem. Conventional cytology detects such tumors with 50% sensitivity, and addition of DNA measurements to cytology only improves sensitivity incrementally. Tumor-associated antigens potentially offer an additional diagnostic marker.

METHODS

In this study, the M344 antibody against a tumor-associated antigen expressed mainly by low-grade tumor cells was tested for its sensitivity and specificity, alone and in combination with DNA ploidy and cytology. Voided urine samples from 69 asymptomatic control subjects, urines and bladder washings from 59 patients with cancer, and 195 symptomatic control patients were collected. Cells were double-labeled with M344 monoclonal antibody and Hoechst. Each case was blinded, and the number of positive cells was scored by two independent observers.

RESULTS

High-grade and low-grade transitional cell carcinomas (TCC) were detected with equal efficiency (78%, P < 0.001 versus symptomatic control patients). Urine samples proved higher specificity in detecting cancers. Patients being monitored for recurrence, but without current detectable cancer, were intermediates between control subjects and patients with cancer, suggesting that this marker also responds to dysplasia or field disease. Patients with outlet obstruction did not significantly differ from patients with previous TCC (P = 0.95). When combined with DNA ploidy measurements and cytology, the sensitivity for low-grade and high-grade tumors was 88% and 95%, respectively.

CONCLUSIONS

The M344 antibody potentially could improve the specificity and sensitivity of detection of low-grade bladder tumors in symptomatic and asymptomatic patients as well as monitoring for recurrence, therapeutic response, and assessment of individual risk.

Alterations in phenotypic biochemical markers in bladder epithelium during tumorigenesis

Phenotypic biochemical markers of oncogenesis and differentiation were mapped in bladder biopsies to investigate changes that occur in bladder tumorigenesis and to identify markers for increased bladder cancer risk. Touch preparations from biopsy specimens from 30 patients were obtained from tumors, the adjacent bladder epithelium, and random distant bladder epithelium. Markers, including DNA ploidy, epidermal growth factor receptor (EGFR), and oncoproteins, were quantified in individual cells by using quantitative fluorescence image analysis. Cluster analysis revealed the markers fell into three independent groups: (i) G-actin and EGFR; (ii) ploidy, cytology, and p185 (HER-2/neu oncoprotein) (ERBB2); and (iii) p300, a low-grade tumor antigen. Each marker displayed a gradient of abnormality from distant field to adjacent field to tumor. Different patterns for each marker suggested a developmental sequence of bladder cancer oncogenesis; G-actin was altered in 58% of distant biopsies (vs. 0/6 normals, P < 0.001), ploidy and cytology were altered in < 20% of distant fields and approximately 80% of tumors, and the other markers were intermediate. Patterns of EGFR and p185 suggest low-and high-grade tracks diverge early (P < 0.05 by Mann-Whitney U test for EGFR and ANOVA for p185). In conclusion, this study shows that a sequence of phenotypic changes accompanies development and progression of bladder cancers. Biochemical alterations in cells of the bladder field are often detectable before abnormal pathology, and markers previously thought to be limited to tumors were found in the field. The hierarchy of expression may be useful in identifying high-risk patients, assessing completeness of response to therapy, and monitoring and predicting recurrence.

Effect of exogenous heparin on anchorage-independent growth of fibroblasts induced by transforming cytokines

Heparin at concentrations below 100 micrograms/ml stimulated anchorage-independent growth of NRK 49F (normal rat kidney fibroblasts, American type culture collection) rat fibroblasts at suboptimal cytokine concentrations but inhibited it at higher heparin concentrations regardless of the cytokine concentration. Heparin did not stimulate growth above that seen at optimal cytokine concentrations, suggesting that it alters the cellular response to the cytokines. These data suggest natural protein-glycosaminoglycan interactions play a role in modulating or mediating the actions of transforming cytokines and suggest they may play a role in acquisition of the transformed phenotype.

Urinary glycosaminoglycan excretion as a laboratory marker in the diagnosis of interstitial cystitis

Urinary macromolecular uronate and glycosaminoglycan uronate concentrations were determined in 209 urine specimens obtained from 192 interstitial cystitis patients, 47 asymptomatic normal individuals and 32 spinal cord injury patients. As a group the concentration of macromolecular uronate or glycosaminoglycan uronate was significantly less in the interstitial cystitis patients than in the normal controls. Some interstitial cystitis patients showed low values of macromolecular uronate and glycosaminoglycan uronate. Analysis of the population distributions suggested that macromolecular uronate may have significant value in diagnosis of interstitial cystitis.

Intermediate endpoint biomarkers for chemoprevention

The understanding of intermediate endpoint biomarker expression in relation to the sequential events in bladder tumorigenesis establishes a useful approach for evaluating chemopreventive agents. Biomarkers may be genotypic or phenotypic and function as biomarkers of susceptibility, exposure, effect, or disease. This paper reviews several years of research on biomarkers and their use in monitoring chemoprevention therapy. In initial animal experiments, mice were dosed with N-butyl-N-(4-hydroxybutyl)nitrosamine (OH-BBN) while co-administering N-(4-hydroxyphenyl)retinamide (4-HPR). 4-HPR did not statistically reduce tumor incidence, but did affect tumor differentiation and, consequently, nuclear size and DNA ploidy. These results suggest that nuclear size and ploidy may function as intermediate endpoint biomarkers of effect for oncogenesis and that epigenetic as well as genetic mechanisms may be primary in the oncogenic process. Early biomarkers of effect which occur prior to genetic effects or chromosome aberration may portend a higher probability of being modulated by differentiating agents such as retinoids. In vitro studies demonstrated that RPMI-7666 cells cultured with a phorbol ester tumor promoter (12-O-tetradecanoyl-phorbol-13-acetate) could be redifferentiated with 13-cis-retinoic acid and dimethyl sulfoxide (DMSO). F-actin, a cytoskeletal biomarker with a presumed function in the epigenetic mechanisms of carcinogenesis, could also be normalized in HL-60 cells treated with 4-HPR or DMSO. A clinical evaluation of F-actin in patients with varying degrees of risk confirmed the value of F-actin as a differentiating biomarker useful for bladder cancer risk assessment. The clarification of when the phenotypic changes of F-actin occur in the oncogenic process was achieved when a variety of biochemical changes were mapped in the patients with bladder cancer. These studies confirmed that G-actin, a reciprocal form of F-actin, is increased relatively early in bladder cancer oncogenesis when multiple biomarkers are quantitated in the field, adjacent area, and the tumor. Comparison of each individual biomarker's expression from field, adjacent to tumor, and tumor, and subsequent cluster analysis of these biomarkers, indicated that the possible sequence of phenotypic expression of biomarkers in bladder cancer oncogenesis is from G-actin, to p300 antigen, to epidermal growth factor receptor (EGFR), to p185 (neu oncogene product), to DNA aneuploidy and, finally, to visual morphology.(ABSTRACT TRUNCATED AT 400 WORDS)

Identification of a high risk subgroup of grade 1 transitional cell carcinoma using image analysis based deoxyribonucleic acid ploidy analysis of tumor tissue

The use of deoxyribonucleic acid (DNA) cytometry to identify a subset of patients with grade 1, stage Ta or T1 transitional cell carcinoma at high risk for death or recurrence was investigated in a retrospective study using paraffin blocks from 88 low grade transitional cell carcinomas of the bladder with an absorptiometric video-based image analysis system. Tumors were evaluated for ploidy (70 diploid, 16 aneuploid and 2 tetraploid) and the presence of cells with greater than 5C DNA. Survival analysis of 62 patients with adequate followup (15 to 20 years) showed that 43 of 62 (69%) suffered recurrences and 13 (21%) died of bladder cancer. The single most important predictors of death and recurrence were stem line aneuploidy and the presence of cells with greater than 5C DNA, respectively.

Quantitative fluorescence image analysis of deoxyribonucleic acid ploidy in urine from normal children

Quantitative fluorescence image analysis incorporates the 2 diagnostic techniques of cytological analysis with quantitation of deoxyribonucleic acid (DNA). Exfoliated urinary cells are ideal for analysis by this method, which allows the identification of "rare event" abnormal cells. We evaluated the urine from 50 children who had undergone cystoscopy or were catheterized for other reasons. The urine was free of infection by urinalysis. Cytological analysis demonstrated normal or atypical cells in all patients. Of the patients 1 (2%) had greater than 2 of 500 cells analyzed with greater than 5C DNA and 4 (8%) had greater than 2 of 500 cells with greater than 5C double stranded nucleic acid. These data suggest that it may be "normal" for urine to contain "rare event" abnormal cells. The significance of this finding is unclear at present.

Cellular F-actin levels as a marker for cellular transformation: correlation with bladder cancer risk

Previous findings in cultured cells that differentiated cells had markedly higher F-actin levels than undifferentiated cells (Cancer Res., 50: 2215-2220, 1990) suggested that quantitative F-actin measurements in urinary cells might provide diagnostic or prognostic information by identifying those individuals with cells tending towards a lower degree of differentiation. The feasibility of such an approach was investigated using a risk stratification schema. Bladder wash samples were obtained from 163 symptomatic patients being evaluated for bladder cancer and 41 asymptomatic controls without hematuria or other symptoms consistent with bladder cancer. F-actin levels were evaluated by flow cytometry using a fluorescent phalloidin probe. The risk of bladder cancer was stratified according to biopsy, either DNA ploidy by flow cytometry or quantitative fluorescence image analysis cytology, previous bladder cancer history, and hematuria. A strong correlation between the presence of cells with abnormally low F-actin content in cells obtained by bladder wash from 38 patients and biopsy-proved bladder transitional cell carcinoma (P less than 0.001) was observed. A strong correlation was also observed between the presence of cells with low F-actin content and risk of bladder cancer assessed by either stratification schema (P less than 0.0001). The correlation was more consistent with the stratification by quantitative fluorescence image analysis cytology because of the 37% false-positive rate of ploidy analysis by flow cytometry among the control patients. Further evidence that low F-actin was correlated with cellular abnormality was obtained from simultaneously labeling cells for F-actin and with M344 antibody, a monoclonal antibody against a low-grade bladder tumor-related antigen. These studies showed that the F-actin content of the M344-positive cells was lower than that of the M344-negative cells. These results suggest that F-actin could be an early and sensitive marker for bladder cancer detection and risk prognostication.

Molecular and cellular biological approaches and techniques in the detection of bladder cancer and enhanced risk for bladder cancer in high-risk groups

Recent advances in molecular cell biology, immunology, and toxicology enhance detection of actual and incipient disease and the definition of risk. Tumor-associated antigens may greatly improve detection of low-grade tumor cells. Several new strategies depend upon detecting molecular lesions of the genes controlling cell growth (oncogenes) at either the gene or protein levels. Highly sensitive techniques detecting DNA adducts are refining the ability to detect specific DNA damage shortly after exposure. The recognition of controls that actively stop proliferation (tumor suppressor genes), regulate differentiation or of relationships between metabolism and carcinogenesis may lead to new ways to identify persons genetically at increased risk from carcinogenic exposure. Current technologies, those on the near horizon, and long-term research needs are analyzed critically in terms of screening objectives.

Quantitative fluorescence image analysis in bladder cancer screening

Quantitative fluorescence image analysis (QFIA) cytology combines image analysis to measure DNA with visual cytology for bladder cancer detection. QFIA sensitivity is 76% to 81% and 95% to 100% for low- and high-grade tumors respectively, with 94% specificity in asymptomatic controls. QFIA screening of 504 persons within a beta-naphthylamine exposed cohort found DNA hyperploidy correlated with the duration of carcinogenic exposure and smoking history; marker prevalence was 23% for exposed workers who smoked and 2% for nonexposed nonsmokers. In prospective animal studies, QFIA was useful in monitoring carcinogenesis and chemoprevention with retinoids. Current QFIA research focuses on measurements of oncogenes, growth factors and their receptors, cytoskeleton, and tumor-associated antigens to improve sensitivity and specificity to low-grade tumors and to identify premalignant conditions. Profiles of biochemical and immunological markers on single cells may further assist in the study of high-risk cohorts and individual risk assessment.

Cellular F-actin levels as a marker for cellular transformation: relationship to cell division and differentiation

Transformation is associated with profound structural and quantitative changes in the cytoskeleton. Herein we report studies using F-actin, a major cytoskeletal protein, as a quantitative marker for transformation cells, focusing on separating the effects of the cell cycle, cell differentiation, and transformation. The model system for these studies consisted of three lymphoblastic cell lines, one untransformed line (RPMI) and two transformed lines, one (HL-60) of which can be induced to differentiate and the other (Daudi) which cannot. The relation of F-actin levels to cell cycle was studied by flow cytometry with the use of fluorescein-phalloidin to label F-actin and propidium iodide to label DNA. F-actin levels in transformed Daudi and HL-60 lines were only two-thirds that of the untransformed RPMI cells. Histograms of the distribution of F-actin showed that the transformed lines consisted of two cell populations, one having an F-actin content near that of untransformed cells and the other having much less. Cell cycle analysis showed that F-actin in untransformed cells increased 10-15% as cells entered the S compartment, remaining approximately constant through G2 + M phases of the cell cycle, but in transformed cells the major increase in F-actin occurred during G2 + M phase. Double-label studies with rhodamine-phalloidin for F-actin and KI-67 monoclonal antibody for dividing cells (cells at late G1, S, G2, and M) measured with quantitative fluorescence image analysis showed that the mean F-actin content of dividing cells was twice that of nondividing cells. These results suggested that most of the cell division-related F-actin increase occurred during late G1 phase in untransformed cells. Differentiation of HL-60 cells with dimethyl sulfoxide or retinoic acid normalized the F-actin content of the nondividing cell population, but dimethyl sulfoxide and retinoic acid produced no detectable change in F-actin in the undifferentiable Daudi cells. A tumor promoter (12-O-tetradecanoylphorphol-13-acetate) inhibits differentiation of hematopoietic cells, resulted in a 32% decrease in the mean F-actin content of RPMI cells due to the appearance of a new subpopulation of low F-actin content. The 12-O-tetradecanoylphorbol-13-acetate-induced changes reversed slowly after removal of 12-O-tetradecanolyphorbol-13-acetate but more rapidly in the presence of retinoic acid. These results indicate that F-actin quantification can serve as a marker for cellular transformation and provides a tool for studying the mechanisms of cellular differentiation that may lead to a better understanding of the oncogenic process.

Decreased urinary uronic acid levels in individuals with interstitial cystitis

The pathogenesis of interstitial cystitis currently is unknown. A possible etiology is that the transitional epithelium is defective, leading to molecular leaks that initiate the disease complex. An important surface defense mechanism is the glycosaminoglycans or polysaccharides that line the bladder epithelium and act as a nonspecific antiadherence factor blocking access of bacteria, microcrystals, proteins and ions to the underlying transitional cells. We examined the excretion of urinary macromolecular uronic acid and glycosaminoglycans in normal individuals and those with interstitial cystitis. A total of 37 controls had a mean macromolecular uronic acid level of 56 nmol. per mg. creatinine, compared to 40.2 nmol. per mg. creatinine in 43 patients with active disease (differences were significant, p equals 0.03). The median excretions of glycosaminoglycan uronate for controls and patients were 15.1 and 11.1 nmol. per mg. creatinine, respectively. (There was an over-all tendency to decrease excretion in patients with a p value of 0.06.) Specimens obtained at cystoscopy from patients with active interstitial cystitis had ureteral macromolecular uronic acid levels of 40.5 nmol. uronate per mg. creatinine compared to 43.6 nmol. uronate per mg. creatinine from the bladder. Interstitial cystitis patients had 16.0 nmol. glycosaminoglycan uronate per mg. creatinine compared to 14.6 nmol. per mg. creatinine in normal controls. Neither of these differences was statistically significant. It would appear that there is a tendency to lower macromolecular uronic acid and polysaccharide excretion in individuals afflicted with this syndrome.

Quantitative immunofluorescence, anti-ras p21 antibody specificity, and cellular oncoprotein levels

A general approach to investigating specificity and saturation of antibodies by quantitative immunofluorescence is applied to monoclonal antibodies generated against p21 or ras oligopeptides to quantify ras p21 oncoprotein in cultured cells. Ras 10, a panreactive mouse monoclonal antibody, appears to be a superior probe for detection of p21 in cell extracts or fixed cells because it binds a 21 kD protein on SDS-PAGE/western blots and labels the cytoplasmic membrane in a saturable and competitive manner. RAP-5, a widely used mouse monoclonal antibody generated against an oligopeptide of ras p21, does not recognize p21 in denaturing immunoblots or in immunofluorescence of cultured cells.

Early detection of colorectal cancer by quantitative fluorescence image analysis of exfoliated cells

Early-stage colorectal cancer is potentially curable. In the present study, we applied quantitative fluorescence image analysis (QFIA) cytology to the detection of experimental colorectal cancer in a rodent model. QFIA cytology combines visual cytologic examination with quantitation of DNA content in single exfoliated cells. Cancer was induced by treating 110 rats with subcutaneous 1,2-dimethylhydrazine. Sequential colon washes were obtained weekly from each animal for 20 weeks. Control animals were treated identically except for the administration of carcinogen. Cells that were cytologically abnormal or had increased DNA content were found starting in the second week. By the eighth week, roughly 50 percent of animals had positive results, and this level remained approximately constant for the duration of the study. Tissue pathologic results were normal during weeks 1 to 7. Dysplasias became common during weeks 8 to 15 whereas most cancers appeared during weeks 16 to 21. These results indicate that QFIA cytology is a highly sensitive method for detecting even preneoplastic changes resulting from carcinogen administration and may prove useful in detecting human colorectal cancer.

Equilibrium binding of Hoechst 33258 and Hoechst 33342 fluorochromes with rat colorectal cells

We examined the biophysical characteristics of the interaction of Hoechst 33258 and 33342 dyes with normal rat colorectal cells as functions of fixation and solution composition. Classical dye-binding techniques were used to investigate the stoichiometry and binding constants with whole cells, and quantitative fluorescence image analysis was used to specifically study nuclear dye binding in intact cells. In aqueous solution, H-33258 dye bound cooperatively with intact cells, with a binding constant of between 3-4 x 10(5). In ethanolic solution, binding appeared less cooperative, although Scatchard analysis could not be used. The binding constant was slightly lower (2 x 10(5)), but the total number of cell binding sites was decreased by a factor of 5, reflecting a great decrease in cytoplasmic sites. QFIA studies identified conditions optimal for DNA quantitation under which the fluorescence signal was independent of dye or cell concentration. The proportionality between absolute nuclear fluorescence intensity and DNA content was established, and the upper limit of DNA content of normal colorectal cells was also determined.

The identification of a heparin-binding protein on the surface of bovine sperm

We report the identification of a sperm surface protein which binds tightly to heparin. The protein was isolated by affinity chromatography on heparin agarose, and its affinity for heparin was confirmed by electrophoresis in the presence of heparin under non-denaturing conditions. The protein consists of a single polypeptide chain with a molecular weight of 45,000, as determined by electrophoresis under denaturing conditions. The protein may bind glycosaminoglycans in vivo and play a part in initiating the capacitation/acrosome reaction.

DNA cytometry and cytology by quantitative fluorescence image analysis in symptomatic bladder cancer patients

A semi-automated quantitative fluorescence image analysis (QFIA) technique was developed with the Leitz TAS-Plus to detect bladder cancer using hyperploidy in urinary cells. Absolute nuclear fluorescence intensity (ANFI) (emission at 540 nm with excitation at 436 nm) of individual acridine-orange-stained cells was quantitated using (1) QFIA and (2) simple filter microspectrofluorophotometry (SFM). Both methods employed an internal phosphor particle standard which, when once calibrated against the DNA content of normal cells, obviates the necessity of routinely calibrating against normal cells in each sample. Results of SFM and QFIA were compared with routine Papanicolaou (Pap) cytopathology, using histopathology as the diagnostic standard in 272 samples from 67 symptomatic patients. The sensitivities for detecting low-grade transitional-cell carcinoma were 86% for SFM, 76% for QFIA, and 33% for Pap cytology. QFIA and SFM were significantly more sensitive at detecting bladder cancer than was Pap (0.01 greater than p greater than 0.001). Comparison of sensitivity obtained with bladder washings and urine samples showed that noninvasively obtained urines can be used. ANFI also detected recurrent and precancerous bladder lesions and kidney, ureter, and prostate lesions. This approach may prove generally useful in quantifying biochemical and immunological probes and should be broadly applicable as a research tool for studying the relationship of biochemical markers in the pathogenesis of disease and as a test for cancer control.

Functional and structural characteristics of the glycosaminoglycans of the bladder luminal surface

The glycosaminoglycan layer of bladder has been proposed to play a crucial role in protecting the bladder from harmful substances in urine. Rats were partially cystectomized to determine whether bladder glycosaminoglycans are routinely eluted from the bladder surface in detectable quantities. Cystectomy produced no detectable qualitative or quantitative changes in excreted GAG thereby showing that most urinary glycosaminoglycan originates in the kidney and not from the bladder. Damaging the glycosaminoglycan layer by a dilute acid wash, however, leads to a consistent decrease in the output of urinary GAG which recovers to normal at the same rate as the layer regenerates. This suggests that the newly exposed sites tightly bind urinary GAG. We suggest that such binding may be a component of the normal physiological defense mechanism of the bladder. The bladder glycosaminoglycan layer was isolated, dilute acid being used to elute ionically-bound material and brief trypsinization to elute intercalated proteoglycans from the luminal surface. The GAG from the luminal surface, which was present at a density of one chain per 50 nm.2 of bladder surface, was quite different in composition from that isolated from the whole bladder.

Heparin binding is necessary, but not sufficient, for fibronectin aggregation. A fluorescence polarization study

Analysis of parameters governing heparin binding to fibronectin indicates that heparin binding is a necessary, but insufficient, condition for fibronectin cryoprecipitation. Heparin binding to fibronectin is a rapid, readily reversible event which can occur under several conditions which prohibit fibronectin cryoprecipitation. While cryoprecipitation of fibronectin is abolished at temperatures in excess of 10 degrees C, appreciable heparin binding to fibronectin does occur even at 40 degrees C. While increasing ionic strength and pH inhibit both heparin binding and cryoprecipitation of fibronectin, heparin binding can still occur at high ionic strengths and pH values which completely abolish cryoprecipitation. Scatchard analysis of fluorescent polarization data reveals a biphasic heparin binding curve with high and low affinity Kd values of 3.5 X 10(-8) and 10(-6) M, respectively. In contrast to heparin binding, fibronectin aggregation is a cooperative phenomenon. Fibronectin cryoprecipitation is greatly reduced at temperatures above 10 degrees C, at pH values above pH 10, and at ionic strengths above 0.3 M. Thus, heparin binding and protein aggregation are separate events which occur during fibronectin cryoprecipitation. Results obtained here via fluorescence polarization in conjunction with other physical measurements suggest that a decrease in flexibility of the fibronectin molecule is associated with the protein aggregation step of cryoprecipitation. The role of heparin in the mechanism of fibronectin cryoprecipitation is discussed.

Structural analysis of heparin by methylation and g.l.c.-m.s.: preliminary results

Heparin is a complex mixture of polysaccharides differing in biological activity and structure, and attempts to relate this activity to structure have suffered, owing to a lack of sufficiently sensitive and specific analytical methods. Application of methylation analysis to determination of the structure of heparin is described. Carboxyl-reduced heparin was converted into its pyridinium salt, this was dissolved in Me2SO, and free OH and NH groups were methylated with dimethylsulfinyl anion. Sulfate groups were removed by solvolysis, and after dialysis, the polymer was acetylated and depolymerized by acetolysis. The resulting monosaccharides were converted into alditol acetates, which were separated by capillary, gas-liquid chromatography, and identified by both electron impact and chemical ionization mass spectrometry. Seventeen different monosaccharides were identified in the hydrolyzate. All of the expected internal hexosaminyl and glycosyluronic residues were identified. Although several sugars were identified as nonreducing termini, only a hexosamine 6-sulfate was identified as a reducing-terminus sugar. The results indicate that methylation analysis of heparins and other complex, sulfated glycosaminoglycans is feasible.

Structure-activity relationships of heparin. Independence of heparin charge density and antithrombin-binding domains in thrombin inhibition by antithrombin and heparin cofactor II

To better understand how heparin structure affects its activity the relationships between the functional domains for inhibitor binding and charge density were investigated to determine how these domains affect heparin-mediated thrombin inhibition by two different heparin-dependent protease inhibitors, antithrombin (AT) and heparin cofactor II (HC II). A series of heparins, fractionated systematically by charge density, was further fractionated on antithrombin agarose to isolate more homogeneous subfractions that were either inactive or highly active with respect to thrombin inhibition by AT. With AT, the activities of the AT-active subfractions increased sharply with heparin charge density, while those with little or no affinity for AT were virtually inactive. In contrast, with HC II inhibitor, the activities of the heparins depended only upon their charge densities and were independent of AT affinity. At any given charge density, the heparin before fractionation by AT affinity and the fractions that were highly active and inactive with AT were all equally active with HC II. The two inhibitors also differed in their reactivity with heparan sulfate and dermatan sulfate. A charge-density effect with the subfractions having similar high affinity for AT demonstrates that charge density represents a heparin functional domain that is independent of the AT-binding domain. The behavior of the AT-inactive heparins, being fully active with HC II, demonstrates the functional domain necessary for AT binding is not needed to produce HC II activity.

Glycosaminoglycans in human neutrophils and leukemic myeloblasts: ultrastructural, cytochemical, immunologic, and biochemical characterization

Chondroitin sulfate is known to be present in normal and leukemic myeloid cells; however, its definitive subcellular location and association with other glycosaminoglycans (GAGs) has not been demonstrated. We have studied the type and distribution of GAGs in neutrophil granule subpopulations of normal and leukemic myeloid cells using ultrastructural, cytochemical, immunologic, and biochemical methods. At the ultrastructural level, high-iron diamine-thiocarbohydrazide-silver proteinate (HID-TCH-SP) stained sulfated glycoconjugates selectively in immature primary granules of normal promyelocytes and Auer rods and immature granules of leukemic myeloblasts. Staining was weak or absent in mature primary granules, whereas tertiary granules stained moderately. Primary granule staining with HID-TCH-SP was greatly diminished by prior treatment of the specimens with chondroitinase ABC and/or nitrous acid, indicating the presence of chondroitin sulfate and N-sulfated glycosaminoglycan. Immunostaining of myeloid cells with a rabbit antichondroitin 4-sulfate and ferritin-conjugated goat anti-rabbit IgG sequence resulted in staining of most primary granules. Biochemical analysis of GAGs from leukemic myeloblasts containing primary granules and Auer rods, but lacking secondary and tertiary granules, revealed 8 x 10(-17) mole of uronic acid/cell and electrophoretic and sulfaminohexose analysis showed 60%-70% chondroitin sulfate AC of heterogeneous molecular weight, 20%-30% of a GAG that most closely resembled heparan sulfate, and 10% dermatan sulfate. The lack of significant HID-TCH-SP staining of sulfate iin sites other than Auer rods and primary granules in leukemic myeloblasts indicates that these granules contain the chondroitin, dermatan, and heparan sulfate isolated from the same specimen. Similar GAGs are present in primary granules of normal cells as evidenced by their cytochemical and immunostaining properties. Thus, these studies demonstrate a heterogeneous population of GAGs not previously identified and localize these substances to the primary granule of leukemic and normal cells.