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Reference Data on Neonatal Serum N-Acetyl- β-hexosaminidase Activity. DISEASE MARKERS 2018; 2018:6187245. [PMID: 30057650 PMCID: PMC6051087 DOI: 10.1155/2018/6187245] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/16/2018] [Revised: 04/12/2018] [Accepted: 05/13/2018] [Indexed: 11/24/2022]
Abstract
Background Determination of neonate serum's N-acetyl-β-hexosaminidase (HEX) activity and correlation results with Apgar scale and factors routinely determined in newborn serum. Aims Providing reference values of neonates serum HEX activities, and indicate their diagnostic significance. Study design The study was performed using random serum samples of 111 infants (53 ♂/58 ♀), aged 1–30 days. The activity of HEX was determined colorimetrically and expressed in nKat/L. Results Serum HEX activity of 111 newborns was 360.5 ± 114.0 nKat/L and significantly positively correlated with gestation week at the day of delivery, birth weight, weight on day of blood collection, sex, and serum CRP. Conclusions Reference values presented for neonatal serum activities of HEX may be used in neonatal diagnostics, for example, to detect inflammation and other diseases or for early assessment of the risk of Tay-Sachs and Sandhoff diseases.
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Zorec R, Parpura V, Verkhratsky A. Astroglial vesicular network: evolutionary trends, physiology and pathophysiology. Acta Physiol (Oxf) 2018; 222. [PMID: 28665546 DOI: 10.1111/apha.12915] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2017] [Revised: 05/17/2017] [Accepted: 06/24/2017] [Indexed: 12/13/2022]
Abstract
Intracellular organelles, including secretory vesicles, emerged when eukaryotic cells evolved some 3 billion years ago. The primordial organelles that evolved in Archaea were similar to endolysosomes, which developed, arguably, for specific metabolic tasks, including uptake, metabolic processing, storage and disposal of molecules. In comparison with prokaryotes, cell volume of eukaryotes increased by several orders of magnitude and vesicle traffic emerged to allow for communication between distant intracellular locations. Lysosomes, first described in 1955, a prominent intermediate of endo- and exocytotic pathways, operate virtually in all eukaryotic cells including astroglia, the most heterogeneous type of homeostatic glia in the central nervous system. Astrocytes support neuronal network activity in particular through elaborated secretion, based on a complex intracellular vesicle network dynamics. Deranged homeostasis underlies disease and astroglial vesicle traffic contributes to the pathophysiology of neurodegenerative (Alzheimer's disease, Huntington's disease), neurodevelopmental diseases (intellectual deficiency, Rett's disease) and neuroinfectious (Zika virus) disorders. This review addresses astroglial cell-autonomous vesicular traffic network, as well as its into primary and secondary vesicular network defects in diseases, and considers this network as a target for developing new therapies for neurological conditions.
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Affiliation(s)
- R. Zorec
- Laboratory of Neuroendocrinology and Molecular Cell Physiology; Institute of Pathophysiology; University of Ljubljana; Ljubljana Slovenia
- Celica; BIOMEDICAL; Ljubljana Slovenia
| | - V. Parpura
- Department of Neurobiology; Civitan International Research Center and Center for Glial Biology in Medicine; Evelyn F. McKnight Brain Institute; Atomic Force Microscopy and Nanotechnology Laboratories; University of Alabama; Birmingham AL USA
| | - A. Verkhratsky
- Laboratory of Neuroendocrinology and Molecular Cell Physiology; Institute of Pathophysiology; University of Ljubljana; Ljubljana Slovenia
- Celica; BIOMEDICAL; Ljubljana Slovenia
- Faculty of Biology; Medicine and Health; The University of Manchester; Manchester UK
- Achucarro Center for Neuroscience; IKERBASQUE; Basque Foundation for Science; Bilbao Spain
- Department of Neurosciences; University of the Basque Country UPV/EHU and CIBERNED; Leioa Spain
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Wendeler M, Sandhoff K. Hexosaminidase assays. Glycoconj J 2010; 26:945-52. [PMID: 18473163 DOI: 10.1007/s10719-008-9137-5] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2008] [Revised: 04/08/2008] [Accepted: 04/09/2008] [Indexed: 10/22/2022]
Abstract
beta-Hexosaminidases (EC 3.2.1.52) are lysosomal enzymes that remove terminal beta-glycosidically bound N-acetylglucosamine and N-acetylgalactosamine residues from a number of glycoconjugates. Reliable assay systems are particularly important for the diagnosis of a family of lysosomal storage disorders, the GM2 gangliosidoses that result from inherited beta-hexosaminidase deficiency. More recently, aberrant hexosaminidase levels have also been found to be associated with a variety of inflammatory diseases. Apart from patient testing and carrier screening, practical in vitro assays are indispensable for the characterization of knock-out mice with potentially altered hexosaminidase activities, for detailed structure-function studies aimed at elucidating the enzymatic mechanism, and to characterize newly described enzyme variants from other organisms. The purpose of this article is to discuss convenient hexosaminidase assay procedures for these and other applications, using fluorogenic or chromogenic artificial substrates as well as the physiological glycolipid substrate GM2. Attempts are also made to provide an overview of less commonly used alternative techniques and to introduce recent developments enabling high-throughput screening for enzyme inhibitors.
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Affiliation(s)
- Michaela Wendeler
- LIMES, Membrane Biology and Lipid Biochemistry Unit, c/o Kekulé-Institut für Organische Chemie und Biochemie der Universität Bonn, Gerhard-Domagk-Str. 1, 53121 Bonn, Germany
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Hegwer G, Fairley C, Charrow J, Ormond KE. Knowledge and attitudes toward a free education and Ashkenazi Jewish carrier testing program. J Genet Couns 2006; 15:61-70. [PMID: 16468087 DOI: 10.1007/s10897-005-9004-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Carrier testing is offered on the basis of Ashkenazi Jewish background in both the prenatal and preconception settings, with the goal of decreasing the prevalence of affected individuals and allowing informed decision-making during childbearing. The purpose of this study was to (1) document the demographic characteristics of individuals who attended a free education and screening program, (2) learn how the education program changed attendees' knowledge and attitudes by learning more about these disorders, and (3) determine how participants perceived their carrier status risk. One hundred seventy-four individuals completed questionnaires at the beginning and end of an educational program about the Ashkenazi Jewish genetic disorders. There was a statistically significant difference in the participant's level of knowledge from the pre- to post education (p < .001). Females reported a significantly higher level of concern about the disorders (p = .004) and their carrier status (p = .006) before the education, as well as about their carrier status post education (p = .05). Finally, having one or more parent affiliated with Orthodox Judaism was related to higher knowledge before the education program (p = .05). In conclusion, this study demonstrated that an educational carrier screening program increased knowledge about the disorders and also produced mild anxiety regarding personal and reproductive risks.
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Affiliation(s)
- G Hegwer
- Center for Genetic Medicine and Graduate Program in Genetic Counseling, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611, USA
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Rozenberg R, Kok F, Burin MG, Sá Miranda MC, Vasques C, Henriques-Souza AMM, Giugliani R, Vainzof M, Pereira LV. Diagnosis and molecular characterization of non-classic forms of Tay-Sachs disease in Brazil. J Child Neurol 2006; 21:540-4. [PMID: 16948947 DOI: 10.1177/08830738060210061101] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Molecular analysis of five Brazilian families, including eight patients presenting with nonclassic Tay-Sachs disease, was performed to identify frequent causative mutations and their correlation with clinical course. Three patients were affected by the B1 subacute variant and were shown to carry the R178H mutation (the DN allele), which is also common among Portuguese patients. Two of them were compound heterozygotes, whereas the third presented with the mutation in both alleles. Since Brazil was a Portuguese colony for over two centuries, common ancestry might be the probable explanation. The fourth patient presented with a juvenile phenotype and carries the R499H mutation, which has been reported only once worldwide and is associated with residual enzyme activity, responsible for a slower clinical course. The fifth family, of an Ashkenazi Jewish background, showed an extensive intrafamilial clinical variability among three affected sibs presenting with muscle atrophy, ataxia, and psychiatric symptoms. They were first diagnosed as having atypical spinal muscular atrophy and, subsequently, spinocerebellar ataxia, but, recently, the diagnosis of late-onset Tay-Sachs disease was confirmed based on reduced plasma hexosaminidase A activity and the G269S/InsTATC1278 genotype. It is therefore highly recommended to test patients with a similar clinical history for Tay-Sachs disease. In the same family, one first cousin committed suicide at the age of 24 years, presenting with a clinical phenotype that suggested an undiagnosed case and highlighting the effect of the intrafamilial clinical variability in delaying a prompt diagnosis. It is now recognized that his parents are, in fact, a carrier couple. Additionally, another relative had been previously identified as a heterozygote in a Tay-Sachs disease screening program, but the information was not shared among the family. Since this information might anticipate diagnosis and genetic counseling, it is advisable that heterozygote screening programs encourage families to share genetic information.
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Affiliation(s)
- R Rozenberg
- Centro de Estudos do Genoma Humano, Instituto de Biociências, Depto. Biologia/Genética, Universidade de São Paulo, Rua do Matão, Travessa 13 no. 106, CEP 05508-900 São Paulo-SP, Brazil
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Casal JA, Cano E, Tutor JC. β-Hexosaminidase isoenzyme profiles in serum, plasma, platelets and mononuclear, polymorphonuclear and unfractionated total leukocytes. Clin Biochem 2005; 38:938-42. [PMID: 16024010 DOI: 10.1016/j.clinbiochem.2005.05.016] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2005] [Revised: 05/09/2005] [Accepted: 05/19/2005] [Indexed: 10/25/2022]
Abstract
OBJECTIVES The relative proportion in percentage of the isoenzyme A of beta-hexosaminidase (Hex) is the single discriminatory function most frequently used for the biochemical screening of heterozygote Tay-Sachs disease carriers. It has been suggested that the assay of the Hex isoenzymes in homogeneous cell preparations is preferable to that in mixed total leukocytes which present greater interindividual variation. The major aim of our study was the evaluation of this hypothesis. DESIGN AND METHODS Total Hex and its Hex A and Hex B isoenzymes were determined in different samples of serum and plasma (n = 81) as well as in lysates of platelets (n = 75), and mononuclear (n = 81), polymorphonuclear (n = 81) and mixed total leukocytes (n = 33). RESULTS The interindividual variations found for % Hex A in the different biological samples were: plasma (CV = 23.4%), platelets (CV = 10.2%), mononuclear (CV = 5.7%), polymorphonuclear (CV = 5.3%) and total leukocytes (CV = 7.1%). Although the relative proportion of Hex A was significantly greater in polymorphonuclear than in mononuclear leukocytes (P < 0.001), a statistical significance was not attained for the correlation between the relative proportions of blood polymorphonuclear cells and Hex A in mixed total leukocytes (r = 0.220). CONCLUSIONS The use of total leukocyte lysates does not appear to introduce a significant increase for the interindividual variation of the Hex A isoenzyme relative proportion in relation to the use of homogeneous cell preparations.
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Affiliation(s)
- J Antonio Casal
- Laboratorio Central, Hospital Clínico Universitario, 15706 Santiago de Compostela, Galicia, Spain
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Abstract
The deficiency of the A isoenzyme of beta-hexosaminidase (Hex) produced by different mutations of the gene that codes for the alpha subunit (Tay-Sachs disease) has two variants with enzymological differences: the B variant consists of the absence of Hex A isoenzyme and the B1 variant produces an inactive Hex A isoenzyme for the hydrolysis of the GM2 ganglioside and synthetic substrates with negative charge. In contrast to the early childhood form of the B variant, the B1 variant appears at a later clinical stage (3 to 7 years of age) with neurodegenerative symptoms leading to the death of the patient in the second decade of life. The most frequent mutation responsible for the GM2 gangliosidosis B1 variant is R178H, which has a widespread geographic and ethnic distribution. The highest incidence has been described in Portugal, which has been suggested as the point of origin of this mutation. Biochemical characterization of this lysosomal disease is carried out using negatively charged synthetic alpha subunit-specific sulfated substrates, since Hex A isoenzyme heat-inactivation assays are not applicable. However, the determination of the apparent activation energy of Hex using the neutral substrate 3,3'-dichlorophenolsulfonphthaleinyl N-acetyl-beta-D-glucosaminide, may offer a valid alternative. The presence of an alpha subunit in the alphabeta heterodimer Hex A means that its activation energy (41.8 kJ/mol) is significantly lower than that of the betabeta homodimer Hex B (75.1 kJ/mol); however, as mutation inactivates the alpha subunit, the Hex A of the B1 variant presents an activation energy that is similar to that of the Hex B isoenzyme.
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Affiliation(s)
- J C Tutor
- Laboratorio Central, Hospital Clínico Universitario, Santiago de Compostela, Spain.
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Casal JA, Pérez LF, Tutor JC. Thermodynamic determination of plasma and leukocyte beta-hexosaminidase isoenzymes in homozygote and heterozygote carriers for the GM2 gangliosidosis B1 variant. Am J Clin Pathol 2003; 119:684-8. [PMID: 12760286 DOI: 10.1309/ahtk-lprk-b4nw-0x5m] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022] Open
Abstract
In the GM2 gangliosidosis B1 variant, the mutated isoenzyme A of beta-hexosaminidase (Hex) is incapable of hydrolyzing ganglioside GM2 and negatively charged substrates. Biochemical characterization of this lysosomal disease is carried out using synthetic alpha-subunit-specific sulfated substrates, as heat-inactivation assays are not applicable. The apparent enzyme activation energy of Hex using the chromogenic substrate 3,3'-dichlorophenolsulfonphthaleinyl N-acetyl-beta-D-glucosaminide is related directly to the relative proportions of Hex A and Hex B isoenzymes. This thermodynamic variable was used for the study of Hex enzyme heterogeneity in 3 patients with the GM2 gangliosidosis B1 variant and 6 heterozygote carriers. Hex activity was determined at 25 degrees C, 30 degrees C, 35 degrees C, and 37 degrees C in a Cobas Bio analyzer (Roche Diagnostics, Basel, Switzerland), and Arrhenius plot slopes and apparent activation energies were calculated in plasma samples and mononuclear and polymorphonuclear leukocyte lysates. The determination of the Hex isoenzymes in plasma presented a high discrimination power for B1 variant patients but not for heterozygote carriers, in whom false-negative results may be obtained. However, thermodynamic evaluation of the isoenzyme composition of Hex in leukocyte lysates permits the biochemical identification of patients with the GM2 gangliosidosis B1 variant and of heterozygote carriers.
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Affiliation(s)
- J Antonio Casal
- Central Laboratory, University Hospital Clinic, Santiago de Compostela, Spain
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Casal JA, Chabás A, Tutor JC. Thermodynamic determination of beta-hexosaminidase isoenzymes in mononuclear and polymorphonuclear leukocyte populations. Am J Med Genet A 2003; 116A:229-33. [PMID: 12503097 DOI: 10.1002/ajmg.a.10891] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Isoenzymes of beta-hexosaminidase (Hex) were determined in mononuclear (MN) and polymorphonuclear (PMN) leukocytes, with a thermodynamic method using the chromogenic substrate sodio-3,3'-dichlorophenolsulfonphthaleinyl N-acetyl-beta-D-glucosaminide. Imprecision was very satisfactory, and the results are very much in agreement with those obtained using the fluorogenic substrates 4-methylumbelliferyl N-acetyl-beta-D-glucosaminide and 4-methylumbelliferyl N-acetyl-beta-D-glucosaminide 6-sulfate. In 163 healthy individuals we found, for the proportion as a percentage of the Hex A isoenzyme, significantly higher values (P < 0.001) in PMN than in MN cells (71.56 +/- 0.30% vs. 54.28 +/- 0.24%), meaning that it would not appear advisable to use total leukocyte lysates for evaluating this variable. The method is fast, precise, and highly suitable for the biochemical diagnosis and heterozygote screening of GM2 gangliosidoses, and would be applicable in cases of thermolabile Hex B and for detecting the B1 variant.
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Affiliation(s)
- J Antonio Casal
- Laboratorio Central, Hospital Clínico Universitario, Santiago de Compostela, Spain
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Schweitzer-Miller L. Tay-Sachs disease: psychologic care of carriers and affected families. ADVANCES IN GENETICS 2002; 44:341-7. [PMID: 11596995 DOI: 10.1016/s0065-2660(01)44090-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Affiliation(s)
- L Schweitzer-Miller
- New York University Psychoanalytic Institute, New York University Medical School, New York 10016, USA
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