- Email: [email protected]
Electrolyte concentrations in saliva of children aged 6-10 years with Down syndrome
Electrolyte concentrations in saliva of children aged 6-10 years with Down syndrome Walter Luiz Siqueira, DDS,a Elisabeth de Oliveira, PhD,b Zan Mustacchi, PhD,c and Jose´ Nicolau, PhD,a Sa˜o Paulo, Brazil ˜ O PAULO AND DARCY VARGAS CHILDREN HOSPITAL UNIVERSITY OF SA
Study design. In this study sodium, potassium, calcium, phosphorus, zinc, and magnesium ion concentration was analyzed in stimulated whole saliva in 22 children with Down syndrome aged 6 to 10 years. These children were compared with 21 healthy children of the same age. Stimulated saliva was collected by chewing a piece of parafilm for 10 minutes. The pH was measured with a portable pH meter after collection. Electrolyte concentrations were determined by inductively coupled argon plasma with atomic emission spectrometry. Results. No statistically significant differences were observed in phosphorus, zinc, magnesium, and calcium concentration between the children with Down syndrome and the control children. The sodium concentration showed about 66.8% higher value in the Down syndrome than in the control group. On the other hand the flow rate and potassium concentration were lower in the Down syndrome than in the control group. Conclusion. Our results suggest that there is alteration in the metabolism of the duct and/or acinar cells of salivary glands of Down syndrome children. (Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2004;98:76-9)
Down syndrome is a disease caused by a trisomy of chromosome 21.1 Its incidence is 1 to 700 live newborns.2 Systemic manifestations in Down syndrome are common, such as recurrent respiratory infections, congenital heart defects, immunologic disorders, and hypothyroidism.3 In the oral cavity, the palate and maxilla are small compared to the mandible.3 There is a delay in the eruption of deciduous and permanent dentitions as well as agenesis of teeth,4,5 a high prevalence of periodontal disease6,7 and low incidence of dental caries.3,8-10 Most of the studies carried out on saliva from people with Down syndrome involved individuals above 10 years of age.11 Calcium and phosphorus are ions found in saliva, directly related to caries incidence, the maturation or remineralization of enamel, and calculus formation. Other ions such as sodium and bicarbonate have a relationship with the buffer capacity.12 The sodium concentration was reported to be high in individuals with Down syndrome; on the other hand, the potassium concentration13 and the activity of the enzymes amylase and peroxidase were reported to be Dr. Nicolau is a recipient of a fellowship from Conselho Nacional de Desenvolvimento Cientı´fico e Tecnolo´gico (CNPq). a Oral Biology Research Center, Faculty of Dentistry, University of Sa˜o Paulo, Brazil. b Institute of Chemistry, University of Sa˜o Paulo. c Darcy Vargas Children Hospital, Sa˜o Paulo, Brazil. Received for publication Dec 15, 2003; returned for revision Jan 28, 2004; accepted for publication Apr 12, 2004. 1079-2104/$ - see front matter Ó 2004 Elsevier Inc. All rights reserved. doi:10.1016/j.tripleo.2004.04.007
reduced in this syndrome.13,14 Other parameters studied, such as total protein and sialic acid concentration, were high in these individuals.11,13 Some authors have described a high salivary pH while others have found no difference between Down syndrome and normal people.11,15,16 The flow rate has been reported to be lower in Down syndrome individuals than the control group.11,17,18 The aim of the present study was to determine the sodium, potassium, calcium, phosphorus, zinc, and magnesium concentration in saliva of children aged 6-10 years with Down syndrome compared with a control group of children of the same age.
MATERIAL AND METHODS The saliva of 43 children (22 with Down syndrome and 21 normal children) aged 6-10 was analyzed. The children with Down syndrome were randomly selected from a population attending the ‘‘Associacxa˜o de Pais e Amigos dos Excepcionais’’ and patients from Darcy Vargas Children Hospital. All Down syndrome children were trisomy 21 diagnosed by karyotype testing. The control group was chosen from patients attending the Dental Clinic of the Faculty of Dentistry, University of Sa˜o Paulo. None of the children had systemic diseases and did not take any medication for at least 15 days before saliva collection. This study was approved by the Ethics Committee of the Faculty of Dentistry of the University of Sa˜o Paulo. Before starting the collection, all parents or guardians were informed of the objective of the investigation and
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a written consent was obtained for the participation of the children in this study. Whole saliva was collected during 10 minutes, always in the morning (8-10 am) to minimize the circadian rhythm effects. The saliva was stimulated by chewing a piece of parafilm (Sigma 10 3 10 centimeters, 1.40 g), and the saliva collected in the first 15 seconds was expectorated or degluted. During the period of collection the children were comfortably seated in a ventilated and lighted room. Soon after the collection, the flow rate was calculated and the pH was measured using a digital portable pH meter. The remaining saliva was frozen in dry ice, conducted to the laboratory, and stored at ÿ808C until the other parameters were analyzed. Analysis of saliva Sodium, potassium, calcium, phosphorus, zinc, and magnesium concentration was analyzed by inductively coupled argon plasma with atomic emission spectrometry.19 The sample was prepared by equal mixture of saliva and 10% nitric acid. Statistical analysis For statistical analysis, the data are presented as a mean 6 SD. The Student’s t- test was used to determine the difference between the mean of the values for the children with the Down syndrome and the normal group. RESULTS The results of the study are presented in Tables I and II. Differences in sodium and potassium concentrations were observed between the groups. The Down syndrome children showed a higher sodium concentration than the children in the control group. The potassium concentration was lower in the Down syndrome children. No difference was observed in phosphorus, zinc, magnesium, and calcium concentration between the 2 groups. The flow rate and pH were significantly lower in the Down syndrome children. In Table II, the results obtained for boys and girls with Down syndrome were compared with those obtained for boys and girls of the control group. The sodium concentration was higher in boys and girls with the Down syndrome than the children of the control group whereas the potassium concentration, flow rate, and pH were lower in both sexes in the Down syndrome group. DISCUSSION This study showed differences in inorganic salivary composition between the Down syndrome group and the control group in children aged 6-10 years. The salivary flow rate was lower in the Down syndrome children.
Table I. Flow rate, pH, and electrolytes of whole saliva from children aged 6-10 years with Down syndrome and control groups. Mean 6 SD Variable Flow rate (mL/min) pH Sodium (mEq/L) Potassium (mEq/L) Phosphorus (mEq/L) Calcium (mEq/L) Zinc (mEq/L) Magnesium (mEq/L)
Control group (n = 21) 0.95 7.76 5.69 7.52 1.10 0.42 0.002 0.06
6 6 6 6 6 6 6 6
0.21 0.30 1.54 1.28 0.31 0.09 0.0012 0.027
Down syndrome group (n = 22) 0.37 7.38 9.49 5.32 1.16 0.45 0.002 0.06
6 6 6 6 6 6 6 6
0.13** 0.31** 2.10** 1.88* 0.31 0.16 0.0009 0.014
*p \ .05. **p \ .01.
These results agree with the literature.17,18 Yarat et al,11 working with unstimulated saliva, found a lower value in saliva from Down syndrome children whose average age was 12.44 years than control. The low flow rate in the Down syndrome individuals suggests a reduction in the clearance of sugar, increasing the risk for oral disease.20 In relation to the salivary pH of individuals with Down syndrome, the studies are conflicting.15,16 Jara et al14 measured the pH of parotid saliva by stimulation with lemon juice swab on the back side of the tongue and found no differences among the Down syndrome patients, normal people, and mentally retarded subjects aged 10-25 years. Shapira et al15 also did not observe differences in the pH of adults with Down syndrome (aged 20-48 years) too. However this same group of researchers16 found differences between Down syndrome group and normal group aged 8-13, but they did not find significant difference in pH between Down syndrome and a mentally retarded group. In both publications,15,16 they used paper pH to measure the pH. In our work13 we have used digital pH, via a potentiometer method. The sodium concentration in saliva of Down syndrome children was higher than in the control group, whereas the potassium concentration was lower. Similar results were showed by Jara et al,14 who found in Chilean children aged 10-25 years with Down syndrome difference in those same ions. Winer and Feller17 observed only a difference in sodium concentration; there was a higher concentration in Down syndrome adults group aged 12-45 years. In this same study no differences in the potassium, chloride, and phosphorus concentrations were observed. The sodium ion is exchanged from primary acinar secretion apparently by both active and passive processes. The effect produced by the duct cells is the removal of sodium; however, a small amount of sodium may also be returned to the
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Table II. Flow rate, pH, and electrolytes of whole saliva comparing boys and girls of the control (C) and Down syndrome (DS) groups. Mean 6 SD Boys Variable Flow rate (mL/min) pH Sodium (mEq/L) Potassium (mEq/L) Phosphorus (mEq/L) Calcium (mEq/L) Zinc (mEq/L) Magnesium (mEq/L)
C (n = 11) 0.97 7.68 5.92 8.05 1.20 0.42 0.002 0.05
6 6 6 6 6 6 6 6
0.36 0.34 1.97 1.40 0.31 0.06 0.001 0.02
Girls DS (n = 12) 0.41 7.41 9.90 6.22 1.29 0.49 0.003 0.06
6 6 6 6 6 6 6 6
0.17** 0.27 2.66** 2.14* 0.37 0.17 0.001 0.01
C (n = 10) 0.84 7.79 5.43 6.93 0.99 0.41 0.003 0.07
6 6 6 6 6 6 6 6
0.25 0.39 0.93 0.85 0.28 0.12 0.001 0.03
DS (n = 10) 0.35 7.36 9.00 4.25 1.01 0.40 0.002 0.07
6 6 6 6 6 6 6 6
0.19** 0.45* 1.12** 0.54** 0.20 0.12 0.0009 0.02
*p \ .05. **p \ .01.
secretions. At high flow rate, the sodium concentration in the saliva increases owing to the lack of active transport mechanisms at the end of the excretory ducts. On the other hand, the potassium ion is added to the salivary secretion by the acini and excretory duct cells. Its concentration is not influenced by the flow rate.21 As shown in Table II, the increase of sodium concentration in the groups with the Down syndrome was 67.2% for the boys and 65.7% for the girls, whereas the potassium concentration diminished 22.7% in the boys with the Down syndrome and 38.7% in the girls, although no significant difference between the boys and girls of the same group was observed. Our results suggest that there is an anomaly in sodium and potassium transport; however, more studies are necessary to determine if there is an error in the sodium/potassium pump. Significant differences in other ions, namely zinc, magnesium, calcium, and phosphorus were not observed. Zinc and magnesium ions are transported to salivary fluid by passive transport. Zinc is part of the cytosolic copper zinc superoxide dismutase enzyme (SOD); in Down syndrome the SOD enzyme has been demonstrated with high activity, because the gene of SOD is localized in the chromosome 21.22 This large activity has been described as the cause of failure in the antioxidant system in these individuals. In conclusion, our results substantiated by the changes in the sodium and potassium concentration and flow rate suggest that there is alteration in the metabolism of the duct and/or acinar cells of salivary glands of Down syndrome children. REFERENCES 1. Lejeune J, Gautier M, Turpin R. Les chromossomes humains en culture de tissues. Comp Rend Acad Sci 1959;248:602-3. 2. Wilson M. Special considerations for the dental professional for patients with Down’s syndrome. J Okla Dent Assoc 1994;84: 24-6.
3. Desai SS. Down syndrome: a review of the literature. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 1997;84:279-85. 4. Kumasaka S, Miyagi A, Sakai N, Shindo J, Kashima I. Oligodontia: a radiographic comparison of subjects with Down syndrome and normal subjects. Spec Care Dent 1997;17: 137-41. 5. Acerbi AG, de Freitas C, de Magalhaes MH. Prevalence of numeric anomalies in the permanent dentition of patients with Down syndrome. Spec Care Dent 2001;21:75-8. 6. Reuland-Bosma W, van Dijk J. Periodontal disease in Down’s syndrome: a review. J Clin Periodontol 1986;13:64-73. 7. Meyle J, Gonzales JR. Influences of systemic diseases on periodontitis in children and adolescents. Periodontol 2000 2001;26:92-112. 8. Hennequin M, Faulks D, Veyrune JL, Bourdiol P. Significance of oral health in persons with Down syndrome: a literature review. Dev Med Child Neurol 1999;41:275-83. 9. Orner G. Dental caries experience among children with Down’s syndrome and their sibs. Arch Oral Biol 1975;20:627-34. 10. Steinberg AD, Zimmerman S. The Lincoln dental caries study: a three-year evaluation of dental caries in persons with various mental disorders. J Am Dent Assoc 1978;97:981-4. 11. Yarat A, Akyuz S, Koc L, Erdem H, Emekli N. Salivary sialic acid, protein, salivary flow rate, pH, buffering capacity and caries indices in subjects with Down’s syndrome. J Dent 1999;27: 115-8. 12. Thylstrup A, Fejerskov O. Textbook of clinical cariology. 2nd ed. Copenhagen: Munksgaard; 1994. pp. 28-35. 13. Siqueira WL, Nicolau J. Stimulated whole saliva components in children with Down syndrome. Spec Care Dent 2002;22: 226-30. 14. Jara L, Ondarza A, Blanco R, Rivera L. Composition of the parotid saliva in Chilean children with Down’s syndrome. Arch Biol Med Exp (Santiago) 1991;24:57-60. 15. Shapira J, Stabholz A, Schurr D, Sela MN, Mann J. Caries levels, Streptococcus mutans counts, salivary pH, and periodontal treatment needs of adult Down syndrome patients. Spec Care Dent 1991;11:248-51. 16. Stabholz A, Mann J, Sela M, Schurr D, Steinberg D, Shapira J. Caries experience, periodontal treatment needs, salivary pH, and Streptococcus mutans counts in a preadolescent Down syndrome population. Spec Care Dent 1991;11:203-8. 17. Winer RA, Feller RP. Composition of parotid and submandibular saliva and serum in Down’s syndrome. J Dent Res 1972;51: 449-54. 18. Chaushu S, Yefenof E, Becker A, Shapira J, Chaushu G. Severe impairment of secretory Ig production in parotid saliva of Down Syndrome individuals. J Dent Res 2002;81:308-12. 19. Korn MGA, Oliveira E. Metal ion behavior in aqueous-organic medium in inductively coupled argon plasma with atomic
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emission spectrometry detection: mercury. ICP Inf Newslett 1995;21:299-303. 20. Sreenbny L. Saliva in health and disease: an appraisal and update. Int Dent J 2000;50:140-61. 21. Ferguson DB. Salivary Electrolytes. In: Tenovuo JO, Human saliva: clinical chemistry and microbiology. Vol. I. Boca Raton: CRC Press; 1989. p. 76-84. 22. Jovanovic SV, Clements D, Macleod K. Biomarkers of oxidative stress are significantly elevated in Down syndrome. Free Rad Biol Med 1998;25:1044-8.
Reprint requests: Dr. Jose´ Nicolau Oral Biology Research Center Faculty of Dentistry, University of Sa˜o Paulo Ave. Prof. Lineu Prestes, 2227 05508-900 Sa˜o Paulo Brazil [email protected]
YMOE674_proof 24 June 2004 1:30 pm
Study design. In this study sodium, potassium, calcium, phosphorus, zinc, and magnesium ion concentration was analyzed in stimulated whole saliva in 22 children with Down syndrome aged 6 to 10 years. These children were compared with 21 healthy children of the same age. Stimulated saliva was collected by chewing a piece of parafilm for 10 minutes. The pH was measured with a portable pH meter after collection. Electrolyte concentrations were determined by inductively coupled argon plasma with atomic emission spectrometry. Results. No statistically significant differences were observed in phosphorus, zinc, magnesium, and calcium concentration between the children with Down syndrome and the control children. The sodium concentration showed about 66.8% higher value in the Down syndrome than in the control group. On the other hand the flow rate and potassium concentration were lower in the Down syndrome than in the control group. Conclusion. Our results suggest that there is alteration in the metabolism of the duct and/or acinar cells of salivary glands of Down syndrome children. (Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2004;98:76-9)
Down syndrome is a disease caused by a trisomy of chromosome 21.1 Its incidence is 1 to 700 live newborns.2 Systemic manifestations in Down syndrome are common, such as recurrent respiratory infections, congenital heart defects, immunologic disorders, and hypothyroidism.3 In the oral cavity, the palate and maxilla are small compared to the mandible.3 There is a delay in the eruption of deciduous and permanent dentitions as well as agenesis of teeth,4,5 a high prevalence of periodontal disease6,7 and low incidence of dental caries.3,8-10 Most of the studies carried out on saliva from people with Down syndrome involved individuals above 10 years of age.11 Calcium and phosphorus are ions found in saliva, directly related to caries incidence, the maturation or remineralization of enamel, and calculus formation. Other ions such as sodium and bicarbonate have a relationship with the buffer capacity.12 The sodium concentration was reported to be high in individuals with Down syndrome; on the other hand, the potassium concentration13 and the activity of the enzymes amylase and peroxidase were reported to be Dr. Nicolau is a recipient of a fellowship from Conselho Nacional de Desenvolvimento Cientı´fico e Tecnolo´gico (CNPq). a Oral Biology Research Center, Faculty of Dentistry, University of Sa˜o Paulo, Brazil. b Institute of Chemistry, University of Sa˜o Paulo. c Darcy Vargas Children Hospital, Sa˜o Paulo, Brazil. Received for publication Dec 15, 2003; returned for revision Jan 28, 2004; accepted for publication Apr 12, 2004. 1079-2104/$ - see front matter Ó 2004 Elsevier Inc. All rights reserved. doi:10.1016/j.tripleo.2004.04.007
reduced in this syndrome.13,14 Other parameters studied, such as total protein and sialic acid concentration, were high in these individuals.11,13 Some authors have described a high salivary pH while others have found no difference between Down syndrome and normal people.11,15,16 The flow rate has been reported to be lower in Down syndrome individuals than the control group.11,17,18 The aim of the present study was to determine the sodium, potassium, calcium, phosphorus, zinc, and magnesium concentration in saliva of children aged 6-10 years with Down syndrome compared with a control group of children of the same age.
MATERIAL AND METHODS The saliva of 43 children (22 with Down syndrome and 21 normal children) aged 6-10 was analyzed. The children with Down syndrome were randomly selected from a population attending the ‘‘Associacxa˜o de Pais e Amigos dos Excepcionais’’ and patients from Darcy Vargas Children Hospital. All Down syndrome children were trisomy 21 diagnosed by karyotype testing. The control group was chosen from patients attending the Dental Clinic of the Faculty of Dentistry, University of Sa˜o Paulo. None of the children had systemic diseases and did not take any medication for at least 15 days before saliva collection. This study was approved by the Ethics Committee of the Faculty of Dentistry of the University of Sa˜o Paulo. Before starting the collection, all parents or guardians were informed of the objective of the investigation and
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a written consent was obtained for the participation of the children in this study. Whole saliva was collected during 10 minutes, always in the morning (8-10 am) to minimize the circadian rhythm effects. The saliva was stimulated by chewing a piece of parafilm (Sigma 10 3 10 centimeters, 1.40 g), and the saliva collected in the first 15 seconds was expectorated or degluted. During the period of collection the children were comfortably seated in a ventilated and lighted room. Soon after the collection, the flow rate was calculated and the pH was measured using a digital portable pH meter. The remaining saliva was frozen in dry ice, conducted to the laboratory, and stored at ÿ808C until the other parameters were analyzed. Analysis of saliva Sodium, potassium, calcium, phosphorus, zinc, and magnesium concentration was analyzed by inductively coupled argon plasma with atomic emission spectrometry.19 The sample was prepared by equal mixture of saliva and 10% nitric acid. Statistical analysis For statistical analysis, the data are presented as a mean 6 SD. The Student’s t- test was used to determine the difference between the mean of the values for the children with the Down syndrome and the normal group. RESULTS The results of the study are presented in Tables I and II. Differences in sodium and potassium concentrations were observed between the groups. The Down syndrome children showed a higher sodium concentration than the children in the control group. The potassium concentration was lower in the Down syndrome children. No difference was observed in phosphorus, zinc, magnesium, and calcium concentration between the 2 groups. The flow rate and pH were significantly lower in the Down syndrome children. In Table II, the results obtained for boys and girls with Down syndrome were compared with those obtained for boys and girls of the control group. The sodium concentration was higher in boys and girls with the Down syndrome than the children of the control group whereas the potassium concentration, flow rate, and pH were lower in both sexes in the Down syndrome group. DISCUSSION This study showed differences in inorganic salivary composition between the Down syndrome group and the control group in children aged 6-10 years. The salivary flow rate was lower in the Down syndrome children.
Table I. Flow rate, pH, and electrolytes of whole saliva from children aged 6-10 years with Down syndrome and control groups. Mean 6 SD Variable Flow rate (mL/min) pH Sodium (mEq/L) Potassium (mEq/L) Phosphorus (mEq/L) Calcium (mEq/L) Zinc (mEq/L) Magnesium (mEq/L)
Control group (n = 21) 0.95 7.76 5.69 7.52 1.10 0.42 0.002 0.06
6 6 6 6 6 6 6 6
0.21 0.30 1.54 1.28 0.31 0.09 0.0012 0.027
Down syndrome group (n = 22) 0.37 7.38 9.49 5.32 1.16 0.45 0.002 0.06
6 6 6 6 6 6 6 6
0.13** 0.31** 2.10** 1.88* 0.31 0.16 0.0009 0.014
*p \ .05. **p \ .01.
These results agree with the literature.17,18 Yarat et al,11 working with unstimulated saliva, found a lower value in saliva from Down syndrome children whose average age was 12.44 years than control. The low flow rate in the Down syndrome individuals suggests a reduction in the clearance of sugar, increasing the risk for oral disease.20 In relation to the salivary pH of individuals with Down syndrome, the studies are conflicting.15,16 Jara et al14 measured the pH of parotid saliva by stimulation with lemon juice swab on the back side of the tongue and found no differences among the Down syndrome patients, normal people, and mentally retarded subjects aged 10-25 years. Shapira et al15 also did not observe differences in the pH of adults with Down syndrome (aged 20-48 years) too. However this same group of researchers16 found differences between Down syndrome group and normal group aged 8-13, but they did not find significant difference in pH between Down syndrome and a mentally retarded group. In both publications,15,16 they used paper pH to measure the pH. In our work13 we have used digital pH, via a potentiometer method. The sodium concentration in saliva of Down syndrome children was higher than in the control group, whereas the potassium concentration was lower. Similar results were showed by Jara et al,14 who found in Chilean children aged 10-25 years with Down syndrome difference in those same ions. Winer and Feller17 observed only a difference in sodium concentration; there was a higher concentration in Down syndrome adults group aged 12-45 years. In this same study no differences in the potassium, chloride, and phosphorus concentrations were observed. The sodium ion is exchanged from primary acinar secretion apparently by both active and passive processes. The effect produced by the duct cells is the removal of sodium; however, a small amount of sodium may also be returned to the
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Table II. Flow rate, pH, and electrolytes of whole saliva comparing boys and girls of the control (C) and Down syndrome (DS) groups. Mean 6 SD Boys Variable Flow rate (mL/min) pH Sodium (mEq/L) Potassium (mEq/L) Phosphorus (mEq/L) Calcium (mEq/L) Zinc (mEq/L) Magnesium (mEq/L)
C (n = 11) 0.97 7.68 5.92 8.05 1.20 0.42 0.002 0.05
6 6 6 6 6 6 6 6
0.36 0.34 1.97 1.40 0.31 0.06 0.001 0.02
Girls DS (n = 12) 0.41 7.41 9.90 6.22 1.29 0.49 0.003 0.06
6 6 6 6 6 6 6 6
0.17** 0.27 2.66** 2.14* 0.37 0.17 0.001 0.01
C (n = 10) 0.84 7.79 5.43 6.93 0.99 0.41 0.003 0.07
6 6 6 6 6 6 6 6
0.25 0.39 0.93 0.85 0.28 0.12 0.001 0.03
DS (n = 10) 0.35 7.36 9.00 4.25 1.01 0.40 0.002 0.07
6 6 6 6 6 6 6 6
0.19** 0.45* 1.12** 0.54** 0.20 0.12 0.0009 0.02
*p \ .05. **p \ .01.
secretions. At high flow rate, the sodium concentration in the saliva increases owing to the lack of active transport mechanisms at the end of the excretory ducts. On the other hand, the potassium ion is added to the salivary secretion by the acini and excretory duct cells. Its concentration is not influenced by the flow rate.21 As shown in Table II, the increase of sodium concentration in the groups with the Down syndrome was 67.2% for the boys and 65.7% for the girls, whereas the potassium concentration diminished 22.7% in the boys with the Down syndrome and 38.7% in the girls, although no significant difference between the boys and girls of the same group was observed. Our results suggest that there is an anomaly in sodium and potassium transport; however, more studies are necessary to determine if there is an error in the sodium/potassium pump. Significant differences in other ions, namely zinc, magnesium, calcium, and phosphorus were not observed. Zinc and magnesium ions are transported to salivary fluid by passive transport. Zinc is part of the cytosolic copper zinc superoxide dismutase enzyme (SOD); in Down syndrome the SOD enzyme has been demonstrated with high activity, because the gene of SOD is localized in the chromosome 21.22 This large activity has been described as the cause of failure in the antioxidant system in these individuals. In conclusion, our results substantiated by the changes in the sodium and potassium concentration and flow rate suggest that there is alteration in the metabolism of the duct and/or acinar cells of salivary glands of Down syndrome children. REFERENCES 1. Lejeune J, Gautier M, Turpin R. Les chromossomes humains en culture de tissues. Comp Rend Acad Sci 1959;248:602-3. 2. Wilson M. Special considerations for the dental professional for patients with Down’s syndrome. J Okla Dent Assoc 1994;84: 24-6.
3. Desai SS. Down syndrome: a review of the literature. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 1997;84:279-85. 4. Kumasaka S, Miyagi A, Sakai N, Shindo J, Kashima I. Oligodontia: a radiographic comparison of subjects with Down syndrome and normal subjects. Spec Care Dent 1997;17: 137-41. 5. Acerbi AG, de Freitas C, de Magalhaes MH. Prevalence of numeric anomalies in the permanent dentition of patients with Down syndrome. Spec Care Dent 2001;21:75-8. 6. Reuland-Bosma W, van Dijk J. Periodontal disease in Down’s syndrome: a review. J Clin Periodontol 1986;13:64-73. 7. Meyle J, Gonzales JR. Influences of systemic diseases on periodontitis in children and adolescents. Periodontol 2000 2001;26:92-112. 8. Hennequin M, Faulks D, Veyrune JL, Bourdiol P. Significance of oral health in persons with Down syndrome: a literature review. Dev Med Child Neurol 1999;41:275-83. 9. Orner G. Dental caries experience among children with Down’s syndrome and their sibs. Arch Oral Biol 1975;20:627-34. 10. Steinberg AD, Zimmerman S. The Lincoln dental caries study: a three-year evaluation of dental caries in persons with various mental disorders. J Am Dent Assoc 1978;97:981-4. 11. Yarat A, Akyuz S, Koc L, Erdem H, Emekli N. Salivary sialic acid, protein, salivary flow rate, pH, buffering capacity and caries indices in subjects with Down’s syndrome. J Dent 1999;27: 115-8. 12. Thylstrup A, Fejerskov O. Textbook of clinical cariology. 2nd ed. Copenhagen: Munksgaard; 1994. pp. 28-35. 13. Siqueira WL, Nicolau J. Stimulated whole saliva components in children with Down syndrome. Spec Care Dent 2002;22: 226-30. 14. Jara L, Ondarza A, Blanco R, Rivera L. Composition of the parotid saliva in Chilean children with Down’s syndrome. Arch Biol Med Exp (Santiago) 1991;24:57-60. 15. Shapira J, Stabholz A, Schurr D, Sela MN, Mann J. Caries levels, Streptococcus mutans counts, salivary pH, and periodontal treatment needs of adult Down syndrome patients. Spec Care Dent 1991;11:248-51. 16. Stabholz A, Mann J, Sela M, Schurr D, Steinberg D, Shapira J. Caries experience, periodontal treatment needs, salivary pH, and Streptococcus mutans counts in a preadolescent Down syndrome population. Spec Care Dent 1991;11:203-8. 17. Winer RA, Feller RP. Composition of parotid and submandibular saliva and serum in Down’s syndrome. J Dent Res 1972;51: 449-54. 18. Chaushu S, Yefenof E, Becker A, Shapira J, Chaushu G. Severe impairment of secretory Ig production in parotid saliva of Down Syndrome individuals. J Dent Res 2002;81:308-12. 19. Korn MGA, Oliveira E. Metal ion behavior in aqueous-organic medium in inductively coupled argon plasma with atomic
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emission spectrometry detection: mercury. ICP Inf Newslett 1995;21:299-303. 20. Sreenbny L. Saliva in health and disease: an appraisal and update. Int Dent J 2000;50:140-61. 21. Ferguson DB. Salivary Electrolytes. In: Tenovuo JO, Human saliva: clinical chemistry and microbiology. Vol. I. Boca Raton: CRC Press; 1989. p. 76-84. 22. Jovanovic SV, Clements D, Macleod K. Biomarkers of oxidative stress are significantly elevated in Down syndrome. Free Rad Biol Med 1998;25:1044-8.
Reprint requests: Dr. Jose´ Nicolau Oral Biology Research Center Faculty of Dentistry, University of Sa˜o Paulo Ave. Prof. Lineu Prestes, 2227 05508-900 Sa˜o Paulo Brazil [email protected]
YMOE674_proof 24 June 2004 1:30 pm