Biomedical subjects

J Alroy

Publications and source records attributed to J Alroy.

At least 91 records · Page 5Linked to original sources

PubMed1988

Biology of Giardia lamblia. Detection of N-acetyl-D-glucosamine as the only surface saccharide moiety and identification of two distinct subsets of trophozoites by lectin binding.

Lectins and glycosidases of known sugar specificity were used as probes to analyze the surface carbohydrate moieties of G. lamblia trophozoites and in particular to determine whether chitin or oligomeric D-GlcNAc is present in the trophozoite form of the parasite as well as on the cyst. Of 13 lectins with varying sugar specificity, only D-GlcNAc-specific lectins bound specifically to the trophozoite surface as determined by light microscopy and EM. A striking finding was the identification of two distinct subsets of trophozoites, distinguished by reactivity with WGA and detected by light microscopy and EM as well as by flow cytometry. Unlike the cyst wall, the trophozoite D-GlcNAc residues were resistant to chitinase treatment. In contrast N-acetyl-beta-D-glucosaminidase abolished WGA binding suggesting that the lectin binds to terminal beta-linked D-GlcNAc residues. These residues were identified as being present on surface glycoproteins by Western blotting of parasite membrane proteins using WGA as a probe. This study identifies D-GlcNAc as the only saccharide moiety detectable by lectin binding on the surface of G. lamblia trophozoites and demonstrates that in contrast to the cyst, chitin is not present in the trophozoite. In addition two distinct subsets of trophozoites were identified based on reactivity with WGA and may represent varying stages of differentiation from trophozoite to cyst.

Acetylglucosamine↗

PubMed1988

Clinical classification of neuronal ceroid-lipofuscinosis subtypes.

Neuronal ceroid-lipofuscinosis is the most common class of neurodegenerative disease in children. After decades of study, the biochemical basis for this group of diseases continues to elude scientists. One obstacle has been the difficulty in establishing specific criteria for diagnosis. This paper reviews case material from 65 patients referred to the Shriver Center for study from January, 1984 to December, 1986. The late-infantile type was the most commonly encountered (35%) with a mean age-of-onset of 3.1 +/- 0.5 yr. The juvenile type was slightly less frequent (32%) with a mean age-of-onset of 7.8 +/- 4 yr. The infantile type ranked third (23%); age-of-onset 11 +/- 4 months) and the adult form of the disease was the least common (10%; age-of-onset 25 +/- 4 yr). Consistent clinical findings were a progressive decline in mental faculties and seizures, predominantly of the myoclonic type. Neuroradiological changes of cerebral and cerebellar cortical atrophy were common when studies were obtained more than a year after clinical onset. Ataxia was a frequent manifestation in the late-infantile and juvenile types whereas dystonia was unique to the latter. There was a diversity of ultrastructural findings in skin biopsies between and within types. The absence of findings in a few familial cases necessitated sampling a second tissue such as muscle, particularly when the history was suggestive and urine dolichols were high. Elevated urine dolichol levels was a nonspecific but helpful finding.

Adolescent↗

PubMed1988

Lectin histochemistry of gangliosidosis. II. Neurovisceral tissues from patients with Sandhoff's disease.

Lectin histochemical studies were performed on selected formalin-fixed, paraffin-embedded tissues of patients affected with the O variant of GM2-gangliosidosis (i.e., Sandhoff's disease). The purpose was to identify specific sugar residues of undegraded "stored" substances in cytoplasm of affected cells. We studied neural tissues from 13 patients, visceral tissues from four patients, and placentae from three affected fetuses. Neurons in all 13 cases studied stained with Concanavalia ensiformis agglutinin (Con A) and with Ulex europaeus agglutinin-I (UEA-I). Succinylated wheat germ agglutinin (S-WGA) stained affected visceral cells and astrocytes and macrophages in the central nervous system. These results demonstrate that alpha-D-mannosyl and alpha-L-fucosyl residues, which bind Con A and UEA-I, respectively, are present in affected neurons. Furthermore, they revealed the affected non-neuronal cells and astrocytes contain complex carbohydrates with nonreducing terminal beta-N-acetylglucosamine, which binds S-WGA.

Brain↗

PubMed1988

Lectin histochemistry of gangliosidosis. I. Neural tissue in four mammalian species.

Lectin histochemical studies were performed on paraffin-embedded brain, spinal cord and eye sections of 16 animals from four different species affected with GM1- and GM2-gangliosidosis to identify specific carbohydrate residues in the perikaryon of neurons. We examined tissues from cats, cattle and dogs with GM1-gangliosidosis and from cats, dogs, and swine with GM2-gangliosidosis and compared them to corresponding normal animals. In all but two cases, the neurons stained intensely with Concanavalia ensiformis agglutinin (Con A); in 12 cases they stained with Dolichos biflorus agglutinin; in 10 cases with Ulex europaeus agglutinin-I; in 9 cases with Griffonia simplicifolia-I; and 8 with soybean agglutinin. Neurons from control tissues stained weakly with Con A, but not with any of the other lectins used. Similar staining patterns of neurons were noted in animals affected with the same disorder originating from the same mutant line. These findings highlight the fact that in gangliosidosis, the lectin staining patterns of neurons may be influenced by the deficiency in enzyme activity and by additional unknown but inherited factors.

Animals↗

PubMed1988

Characterization of alpha-mannosidase in feline mannosidosis.

Acidic alpha-mannosidase deficiency has been identified in a family of Blue Persian cats. Characterization of the residual activity revealed that the Km for the substrate, 4-methylumbelliferyl-alpha-D-mannoside, increased approximately three-fold with a severe deficiency in Vmax (1-2%) in homogenates of liver and brain of affected cats compared with controls. The residual activity at pH 4.0 in liver homogenates from affected cats is very thermolabile at 51 degrees C while the control activity is stable at this temperature for 1 h. Subcellular fractionation of liver was performed from a control and diseased cat in order to compare the properties of the different alpha-mannosidases localized in these fractions. The residual activity present in the lysosomal fraction from diseased cat liver showed altered pH optimum, two-fold increase in Km with a severely reduced Vmax and increased thermolability compared with the activity in the lysosomal fraction from control liver. The thermal inactivation pattern and Km of the residual activity in the lysosomal fraction is different from the non-lysosomal alpha-mannosidase in the liver of the affected cat. This suggests that the residual activity in the lysosomal fraction of the liver from the affected cat is not due to contamination of non-lysosomal alpha-mannosidase in this fraction. Whether this residual activity represents the properties of the mutant enzyme or yet another minor normal component of lysosomes different from the major inactive mutant or absent lysosomal enzyme remains to be elucidated.

Animals↗

PubMed1988

The distribution of lectin receptor sites in human breast lesions.

Conflicting data regarding the status of A, B, H and T antigens in epithelium of normal, mastopathies, fibroadenomas and carcinomas of the breast stimulated us to re-examine the carbohydrate residues in these condition. Currently, we extended the number of carbohydrate residues studied by using ten different biotinylated lectins as probes and avidin-biotin-peroxidase complex (ABC) as a visualant. In addition, the pattern of lectin staining of cancerous cells in primary and metastatic sites was compared. In primary and metastatic breast carcinomas, lectin receptor sites were stained more intensely with Concanavalia ensiformi agglutinin (*Con A), Ricinus communis agglutinin-I (RCA-I) and wheat germ agglutinin (WGA), than in normal breast, in mastopathies or in fibroadenomas. Cryptic receptor sites for peanut agglutinin (PNA) were stained in all cases of breast carcinomas, while free PNA sites stained only in a few cases of well-differentiated carcinomas. Receptors sites for Ulex europaeus agglutinin-I (UEA-I) stained non-malignant epithelium of patients with blood group H but did not stain malignant cells. The results show significant differences in lectin-binding patterns and staining intensities between normal and non-malignant, and malignant epithelial breast cells. Furthermore, these results indicate that in malignant cells, there is an increased content of sialic acid-rich carbohydrates but not of asialylated glycoconjugates.

Adenofibroma↗

PubMed1988

Differential lectin staining of central and peripheral zones of the prostate and alterations in dysplasia.

Histochemical staining with a battery of ten lectins demonstrated differences in lectin binding patterns between seminal vesicle, prostatic central and peripheral zones, and foci of prostate intraductal dysplasia, a putative premalignant lesion. Lectin binding patterns of seminal vesicle and central zone of the prostate were identical except for a single lectin, supporting the concept that these two structures have a common embryologic origin from the wolffian duct. Three of the lectins that bound to central zone were not bound in peripheral zone, indicating a biologic difference between these two regions of the prostate. Dysplasia foci showed markedly reduced binding with all lectins, consistent with impaired processing of glyco-conjugates. Lectin binding patterns appear to have value as sensitive markers of differences in terminal differentiation of closely related tissues and of early impairment of differentiated function in lesions that are precursors to carcinoma. Specific patterns of lectin binding provide information on the differential carbohydrate composition of the regions of the prostate.

Adult↗

PubMed1988

Immunohistochemical evidence for impaired cell differentiation in the premalignant phase of prostate carcinogenesis.

Epithelial cell differentiation was evaluated in 15 samples of duct-acinar dysplasia, a putative premalignant lesion of the prostate, through immunohistochemical staining for five differentiation markers. Prostate-specific antigen (PSA), prostatic acid phosphatase (PAP), Leu-7, pepsinogen II (PG II), and tissue plasminogen activator (t-PA) are all constituents of seminal fluid that are produced by prostatic epithelium. Dysplasia foci were classified into three grades of severity and their locations mapped by camera lucida drawings of each slide. The degree of abnormal staining with each antibody was recorded on the map, and its correlation with dysplasia grade was evaluated. PSA, PAP, and Leu-7 staining were reduced in dysplasia and often absent in severe dysplasia, indicating that reduced differentiation is an early change in prostatic carcinogenesis. PG II and t-PA stains were sometimes positive in a region where they are usually absent, suggesting that deregulation of differentiation markers may accompany reduction in differentiation in these preneoplastic lesions.

Acid Phosphatase↗

PubMed1988

Characterization of colonic cellular glycoconjugates in colitis and cancer-prone tamarins versus colitis and cancer-resistant primates.

Differences in colonic secretory glycoconjugates (ie, mucin) between normal and ulcerative colitis-prone patients have been noted. Similar differences may occur in a corresponding primate model, the cotton-top tamarin (CTT), Saguinus oedipus, a New World monkey which suffers from spontaneous chronic colitis and colon cancer. Lectin reagents were used to characterize and compare colonic cell surface, cytoplasmic, and secretory glycoconjugates of 9 clinically healthy cotton-top tamarins, 7 colitis-susceptible, cancer-resistant tamarins (Callithrix jacchus, Saguinus fuscicollis), and 8 colitis and cancer-resistant primates (Aotus trivirgatus, Saimiri sciureus, Macaca fascicularis, and Macaca mulatta). Paraffin-embedded colonic sections were labeled with ten different biotinylated lectins and visualized by the avidin-biotin peroxidase (ABC) method. Significant differences were demonstrated in the pattern of lectin staining between the colitis-resistant and colitis-prone groups of primates. The differences were noted with Griffonia simplicifolia-I (GS-I), Dolichos biflorus agglutinin (DBA), peanut agglutinin (PNA) before and after neuraminidase, Ricinus communis agglutinin-I (RCA-I), soybean agglutinin (SBA), Ulex europaeus agglutinin-I (UEA-I), wheat germ agglutinin (WGA), and succinylated WGA (S-WGA). Significant differences between the CTT and phylogenetically related colitis-prone but cancer-resistant tamarins were demonstrated with SBA, UEA-I, and PNA after desialylation with neuraminidase. These results suggest that differences in colonic cellular glycoconjugates between colitis- and cancer-susceptible species versus colitis-susceptible, cancer-resistant species may be associated with risk of cancer.

Animals↗

PubMed1988

Differences in cellular glycoconjugates of quiescent, inflamed, and neoplastic colonic epithelium in colitis and cancer-prone tamarins.

In the preceding paper the authors demonstrated that the lectin staining patterns of normal colonic epithelium obtained from colitis and carcinoma-prone cotton top tamarins (CTTs), Saguinus oedipus, a New World primate, differs from colitis- and carcinoma-resistant primate species. In this study they determined the usefulness of cytochemical features in inflamed epithelium as indicators for malignant change. They compared the lectin staining pattern in inflamed mucosa and adjacent mucosa with colonic carcinoma from 8 CTTs with that of 9 clinically healthy CTTs with no histologic evidence of colitis. Deparaffinized sections were labeled with ten biotinylated lectins and stained by the avidin-biotin peroxidase complex method. Numerous significant differences were demonstrated in the lectin staining pattern between normal epithelium and colonic carcinoma; fewer between normal and chronic inflamed epithelium. However, between chronic inflamed epithelium and colonic carcinoma significant staining differences were observed with only two lectins, peanut agglutinin (PNA) and Ulex europaeus agglutinin-I (UEA-I). These findings suggest that there is a progression in alteration of lectin staining pattern from normal epithelium, via chronic colitis, to colonic carcinoma. Furthermore, the differences between chronic colitis and colonic carcinoma are expressed only with those lectins that are associated with malignant transformation of human colonic epithelium.

Animals↗

PubMed1987

Lectin histochemistry of mammalian endothelium.

Lectin-histochemical studies were performed on formalin-fixed, paraffin-embedded tissues from ten mammalian species to demonstrate the pattern of carbohydrate residues in vascular endothelium. Ten different biotinylated lectins were used as probes and avidin-biotin-peroxidase complex (ABC) was used as visualant. Ricinus communis agglutinin-I (RCA-I) and wheat germ agglutinin (WGA) stained vascular endothelium in all species. Peanut agglutinin (PNA) stained vascular endothelium in all species only after preincubation with neuraminidase. Bandeirea simplicifolia agglutinin-I (BS-I) stained vascular endothelium in all species but human, while Ulex europeus agglutinin-I (UEA-I) stained only human endothelium. Individual differences in staining of human vascular endothelium were noted with BS-I and succinylated-WGA (SWGA). Similarly, individual differences in staining of animal vascular endothelium were noted with soybean agglutinin (SBA) after preincubation with neuraminidase. Finally, Concanavalia ensiformis agglutinin (Con A), Dolichos biflorus agglutinin (DBA) and Lens culinaris agglutinin (LCA) did not stain vascular endothelium in any of the species studied.

Animals↗

PubMed1987

The use of avidin-gold complex for light microscopic localization of lectin receptors.

In the present study, we have investigated the use of avidin-gold complex (AG) as a possible cytochemical marker for visualizing and identifying lectin receptors in deparaffinized tissue sections. Monodispersed gold sols of 15 nm average diameter were prepared by sodium citrate reduction. The AG complex was prepared with highly purified egg-white avidin (avidin-D). Deparaffinized sections of cat duodenum were labeled with five different biotinylated lectins, then were washed and stained for 1-2 h with AG. Intensification of the gold staining was achieved by a modification of the silver-enhancement method. For each lectin, the labeling properties of the avidin-gold-silver (AGS) were compared with those of the avidin-biotin-peroxidase (ABC) and the lectin-gold (LG) methods. We found the lectin binding pattern demonstrated by the AG method to be similar to that of the ABC. The AG localization of the carbohydrate residues is more precise, compared to the peroxidase reaction due to lack of diffusion of the gold marker. Labeling with AGS resulted in improved staining over the AG method, similar to the staining intensity of the ABC. In addition, the two-step AG method provided more intense staining than the direct one-step procedure of the lectin-gold labeling. In conclusion, the use of the AGS method for histochemical visualization of lectin receptors requires a simple two-step procedure which allows highly accurate localization of tissue glycoconjugates. It entails using only a single gold-ligand complex applicable to any biotinylated lectin regardless of its biochemical nature.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1987

Lectin histochemistry and ultrastructure of feline kidneys from six different storage diseases.

We have compared the pattern of lectin staining with the ultrastructural features of kidneys from normal cats and 19 cats with 6 different lysosomal storage diseases. The diseases studied include GM1 and GM2 gangliosidosis, mucopolysaccharidosis (MPS)-I and MPS-VI, sphingomyelin-lipidosis (i.e., Niemann-Pick disease) and mannosidosis. Ten different biotinylated lectins were used as histochemical probes for carbohydrate residues and avidin-biotin-peroxidase complex as visualant. Concanavalia ensiformis agglutinin (Con A) stained mesangial cells in all storage diseases but GM1, epithelial cells in sphingomyelin-lipidosis and mannosidosis, endothelial cells in GM1 and mannosidosis and Bowman's capsule cells in all but GM2. Griffonia simplicifolia agglutinin I (GS-I) stained the glomerular endothelium in all six diseases, but not in control kidneys. Ricinus communis agglutinin-I (RCA-I) stained the glomerular epithelium only in GM1 and MPS-I. Succinylated wheat germ agglutinin (SWGA) stained the glomerular endothelium and epithelium in mannosidosis, and the glomerular epithelium and Bowman's capsule in MPS-I. Ultrastructure studies demonstrated an accumulation of oligosaccharides in cases of mannosidosis and GM1 gangliosidosis, a mixture of oligosaccharides and lipids in MPS-I, MPS-VI and GM2 gangliosidosis and only lipid storage in sphingomyelin lipidosis. These studies show that morphologic and histochemical changes are manifested in some kidney cell types in lysosomal storage diseases, even though the enzyme deficiency occurs in all cell types. Furthermore, we show that the nature of the undegraded stored material is complex and that other factors, such as rate of membrane turn over, membrane composition, and cell function may influence the amount and nature of the "stored" material.

Animals↗

PubMed1987

Lectin binding in retinoblastoma.

Lectins were used as cytochemical probes to examine the relationship between normal retina and retinoblastoma. Cases of retinoblastoma in which there were either Flexner-Wintersteiner rosettes or fleurettes accompanied by nontumorous retina were studied with ten biotinylated lectins. Pineal and ocular tumors from cases of trilateral retinoblastoma were also studied. Con-A, LCA, PNA, WGA and RCA-I labeled tissue of each type to varying degrees, while BS-I, DBA, SBA, S-WGA and UEA-I bound neither tumor nor retina. The high degree of binding homology suggests biochemical as well as structural similarities between these tissues.

Eye Neoplasms↗

PubMed1987

Modulation of carbohydrate residues in regenerative nodules and neoplasms of canine and feline pancreas.

The glycoconjugates of regenerative acinar cells, acinic cell carcinomas, islet cell tumors, and normal canine and feline pancreas were studied. The authors used biotinylated lectins as probes and avidin-biotin-peroxidase complex as visualant to identify and to compare the distribution of carbohydrate residues on paraffin sections from 74 cases. The findings demonstrate a difference in the staining pattern between normal acinar, islet, and ductal cells in each species and small differences in the staining pattern between the species. It is shown that in nodules of regenerative acinar cells and acinic cell carcinomas there is an increased staining intensity with Concanavalia ensiformis agglutinin, Ricinus communis agglutinin-I, and wheat germ agglutinin. The pattern of lectin staining in regenerative cells and malignant acinar cells reflects the degree of cellular differentiation. Intensive apical staining characterizes a higher degree of differentiation, while dispersed staining is a major feature of poor differentiation. These findings suggest that malignant transformation of pancreatic acinar cells is associated with enhanced expression of glycoconjugates, which resembles that seen in a normal immature acinar cells.

Animals↗

PubMed1987

Lectin histochemistry and ultrastructure of kidneys from patients with I-cell disease.

The undegraded stored material in I-cell disease (ICD) includes mucopolysaccharides, lipids, and oligosaccharides. We used ten different lectins as histochemical probes to identify specific carbohydrate residues in stored materials, and electron microscopy to examine the morphology of abnormally stored material in kidneys from two patients with ICD. In both cases, all the glomerular epithelial cells (ie, podocytes), endothelial cells, and renal tubular cells were enlarged and vacuolated. Ultrastructural studies revealed both fibrillogranular material and lamellated membrane structures in the vacuoles. The cytoplasm of affected cells stained with Concanavalia ensiformis agglutinin, wheat-germ agglutinin, and succinylated-wheat-germ agglutinin, but no corresponding control cells stained with lectins. The latter findings indicate an accumulation of N-linked oligosaccharides containing alpha-mannosyl, beta-N-acetylglucosaminyl, and sialyl residues in renal cells affected by ICD.

Child↗

PubMed1986

Oligosaccharides from placenta: early diagnosis of feline mannosidosis.

High-pressure liquid chromatography analysis of oligosaccharides from placentas allowed the diagnosis of alpha-mannosidosis in three litters of kittens. The chromatography also afforded a detailed comparison of the oligosaccharide pattern and levels in placenta, liver, brain, urine and ocular fluid of the affected animals. In all cases, two series of compounds were observed, with one or two residues of N-acetylglucosamine at the reducing terminus, respectively, and between two and nine mannose residues. This pattern is unlike that of human mannosidosis, and resembles that of ruminants, except that the major oligosaccharide contains three mannose residues instead of two.

Animals↗

PubMed1986

Malignant neoplasms associated with orthopedic implant materials in rats.

The carcinogenic potential of 22 orthopedic prosthetic materials was studied by implantation in bone in Sprague-Dawley rats and evaluated by complete autopsy examination performed at the time of death or at the end of the 30 month experimental period. When the number of malignancies in these rats was compared with control and sham-operated animals, a small increase in sarcomata was observed in animals bearing metal alloy implants containing high contents of cobalt, chromium, or nickel. An increased incidence of lymphomata with bone involvement was also observed in rats bearing metal implants when compared with control and sham-operated animals.

Animals↗