Relationship between clinical measures of hearing and clinical measures of vestibular function

PURPOSE

Patients often have basic audiometry (BA) but not objective diagnostic tests of the vestibular system (VNG) when complaining of symptoms of a vestibular disorder. The relationship of BA results to VNG results is unknown. This study sought to determine if BA scores are related to impaired VNG scores.

MATERIALS AND METHODS

We reviewed electronic medical records at a tertiary care center, for patients seen between 2015 and 2021 who had had both a BA and a VNG (n = 651). BA subtests were pure tone averages, word recognition, and tympanogram. VNG subtests were cervical vestibular evoked myogenic potentials, Dix-Hallpike maneuvers, and bi-thermal caloric tests. All tests were summarized as normal/abnormal.

RESULTS

More subjects had abnormal BA than abnormal VNG scores. Age but not sex was significantly related to abnormal scores. High BP was a significant comorbidity in 15 % of the sample, more in patients with abnormal than normal VNG scores. Although the abnormal BA and abnormal VNG were significantly related, pure tone averages and tympanogram scores were not related to VNG subtests. Abnormal word recognition with both ears combined was significantly related to normal and abnormal bi-thermal caloric tests.

CONCLUSIONS

If the clinician needs to know of any VNG impairment, in general, then performing a BA without a VNG might suffice. If the clinician needs information about the details of possible vestibular impairment, then a VNG should be performed.

Monopolar Cautery Use in Pediatric Cochlear Implant Users

OBJECTIVES

To determine the incidence and impact of monopolar cautery use in a cohort of pediatric cochlear implant (CI) users.

STUDY DESIGN

Case series from a retrospective chart review and a systematic review of the literature.

SETTING

Tertiary academic referral center.

METHODS

CI patient charts from 2012 to 2021 were reviewed from a single pediatric hospital system to determine if monopolar cautery was used during a subsequent surgical procedure. In addition, a systematic review of the literature was performed to identify additional, relevant patients. Postoperative CI function was the primary outcome measure.

RESULTS

In total, 190 patients underwent a surgical procedure following cochlear implantation in a single pediatric hospital system. Fifteen patients (7.9%) and 17 distinct surgical procedures were identified in which monopolar cautery was used. Seven of these 17 cases (41.2%) involved the head and neck, and 10 were performed below the clavicles. No patients experienced a device failure or a decline in CI performance following surgery. A systematic review identified an additional 4 patients who underwent a surgery that used monopolar cautery following cochlear implantation, and no change in CI function was identified.

CONCLUSIONS

The present study adds additional support to the notion that monopolar cautery does not necessarily injure CI functionality. While the most risk adverse strategy when planning a surgical procedure for a CI patient is to avoid monopolar cautery use altogether, the use of cautery should not immediately be associated with implant dysfunction.

Benefits from, Satisfaction with, and Self-Efficacy for Advanced Digital Hearing Aids in Users with Mild Sensorineural Hearing Loss

Little evidence is available regarding outcomes of advanced digital technology (ADT) hearing aid wearers with mild sensorineural hearing loss (MSNHL). The purpose of this article is to report the characteristics of and outcomes for this population. A cross-sectional research design was employed with 56 participants from a private practice setting. The International Outcomes Inventory for Hearing Aids (IOI-HA), Satisfaction with Amplification in Daily Life (SADL), and the Measure of Audiologic Rehabilitation Self-Efficacy for Hearing Aids (MARS-HA) were completed, scored, and compared with normative data. Results revealed that ADT aids were worn 10.5 hours/day, were mostly advanced to premium (55%), had an average cost per aid of $2,138 (SD = $840), and provided significant benefit (IOI-HA overall score: mean = 4.1; SD = 0.6) and satisfaction (SADL global score: mean = 5.4; SD = 0.8) to users who had good overall self-efficacy (MARS-HA composite score: mean = 81.7; SD = 12.8). Patients were most dissatisfied with and had the least self-efficacy for managing background noise and advanced handling of their devices. ADT hearing aid users with MSNHL achieved excellent outcomes, but ongoing follow-up and counseling from hearing health care providers may be important for successful management of background noise and mastery of advanced handling skills.

ET-1 actions in the kidney: evidence for sex differences

Hypertension and chronic kidney disease are more common in men than in premenopausal women at the same age. In animal models, females are relatively protected against genetic or pharmacological procedures that produce high blood pressure and renal injury. Overactivation or dysfunction of the endothelin (ET) system modulates the progression of hypertension or kidney diseases with the ET(A) receptor primarily mediating vasoconstriction, injury and anti-natriuresis, and ET(B) receptors having opposite effects. The purpose of this review is to examine the role of the ET system in the kidney with a focus on the inequality between the sexes associated with the susceptibility to and progression of hypertension and kidney diseases. In most animal models, males have higher renal ET-1 mRNA expression, greater ET(A) -mediated responses, including renal medullary vasoconstriction, and increased renal injury. These differences are reduced following gonadectomy suggesting a role for sex hormones, mainly testosterone. In contrast, females are relatively protected from high blood pressure and kidney damage via increased ET(B) versus ET(A) receptor function. Furthermore, ET(A) receptors may have a favourable effect on sodium excretion and reducing renal damage in females. In human studies, the genetic polymorphisms of the ET system are more associated with hypertension and renal injury in women. However, the knowledge of sex differences in the efficacy or adverse events of ET(A) antagonists in the treatment of hypertension and kidney disease is poorly described. Increased understanding how the ET system acts differently in the kidneys between sexes, especially with regard to receptor subtype function, could lead to better treatments for hypertension and renal disease. LINKED ARTICLES This article is part of a themed section on Endothelin. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2013.168.issue-1.

Endothelin(A) (ET(A)) and ET(B) receptor-mediated regulation of nitric oxide synthase 1 (NOS1) and NOS3 isoforms in the renal inner medulla

AIM

Our laboratory and others have shown that endothelin (ET)-1 directly stimulates nitric oxide (NO) production in inner medullary collecting duct (IMCD) cells. The goal of this study was to determine which NO synthase (NOS) isoforms in IMCD are sensitive to ET-1, and the role of ET(A) and ET(B) receptor activation in vivo and in vitro.

METHODS

NOS enzymatic activity and NOS isoform protein expression were examined in cultured IMCD-3 cells and isolated renal inner medulla. ET(B) receptor-deficient homozygous rats (sl/sl) have elevated levels of circulating ET-1 and lack a functional ET(B) signalling pathway in kidneys, and furthermore provides a unique model to study ET(A) receptor signalling in the renal inner medulla in vivo.

RESULTS

Incubation of IMCD-3 cells with exogenous ET-1 (50 nm) resulted in ET(A)-dependent increased NOS1 protein expression in IMCD-3 cells with no effect on NOS2 or NOS3 expression. ET(B) receptor antagonism has no effect on NOS expression in IMCD-3 cells. Consistent with in vitro results, cytosolic NOS1 protein expression was significantly greater in the renal inner medulla of sl/sl rats compared with heterozygous (sl/+) controls, with no alteration in NOS3 expression. In contrast to protein expression data, NOS1- and NOS3-specific enzymatic activities decreased in the cytosolic fraction from the renal inner medulla of sl/sl compared with sl/+.

CONCLUSION

These results provide evidence that both ET(A) and ET(B) receptors regulate NOS isoform activity in the renal inner medulla and specifically support the hypothesis that ET(A) receptor activation increases NOS1 expression.

Kinetics of the reaction of U(vi) with benzene-1,2-diphosphonic acid

The kinetics of the reaction between dioxouranium(VI) and benzene-1,2-diphosphonic acid (BzDPA) has been investigated by stopped-flow spectrophotometry. The rate of reaction of uranyl ions with Arsenazo III (2,7-bis(2,2'-arsonophenylazo)-1,8-dihydroxynaphthalene-3,6-disulfonic acid) in 50:50 methanol-water solutions was also determined. Both formation and dissociation rate constants for the 1:1 complex between uranyl-BzDPA in acidic solutions were resolved. To gain insight into the effect of solvation on the progress of the reaction, the system was studied in triply distilled water, in 50:50 methanol-water, 80:20 methanol-water and in 50:50 tert-butanol-water as a function of temperature at pH 1.0. The rates of complex formation and dissociation reactions decrease as methanol substitutes for water in the medium and further decrease as tert-butanol replaces methanol as co-solvent. Activation parameters are most consistent with an associative process governing the progress of both complex formation and dissociation reactions. Introduction of alcoholic co-solvents results in notably more negative activation entropies for both complex formation and dissociation reactions, while the activation enthalpies are only slightly reduced in the mixed methanol-water medium. These results are compared with the kinetic features of other U(VI) systems.

NOS 3 subcellular localization in the regulation of nitric oxide production

Endothelium-derived nitric oxide (NO) is a key signalling molecule in the maintenance of cardiovascular health. Endothelial NO synthase (NOS 3), which catalyses the formation of NO, is targeted to the plasma membrane by dual acylation. In vitro studies suggest that membrane localization of NOS 3 is an important regulatory element of NO production. Dysfunction of the vascular endothelium and a decrease in NO bioavailability is associated with the development and progression of a number of cardiovascular diseases, including hypertension. Our laboratory has previously published that in salt-dependent hypertension there is an altered localization of NOS 3, with an increase in cytosolic expression. These data have led us to question whether the increased cytosolic NOS 3 expression is a form of compensation for endothelial dysfunction in hypertension, or an indicator and contributing factor to endothelial dysfunction. This review will outline the importance of subcellular localization in the regulation of NOS 3 in vitro, the role of NOS 3 in endothelial dysfunction associated with salt-dependent hypertension, and the potential physiological consequences of altered NOS 3 localization in vivo.

Creatine supplementation in high school football players

OBJECTIVE

To describe creatine supplementation patterns and behaviors associated with creatine supplementation in high school football players.

DESIGN

A cross-sectional, multisite, anonymous, descriptive survey was conducted between October 1999 and February 2000.

SETTING

37 public high schools in Wisconsin.

SUBJECTS

A total of 1,349 high school football players, grades 9-12.

MAIN OUTCOME MEASURES

Self-reported prevalence of creatine use, as well as perceived benefits and risks. In addition, sources of information and influence regarding creatine supplementation were assessed.

RESULTS

30% of the respondents reported using creatine. Creatine use was lowest in the 9th grade (10.4%) and highest in the 12th grade (50.5%). 41% of the players at small schools stated they used creatine compared with 29% of the players in large schools. Enhanced recovery following a workout was the most likely perceived benefit of creatine supplementation, while dehydration was cited most often as a risk of creatine use. Users were encouraged to take creatine most often by their friends while their parents discouraged creatine use.

CONCLUSIONS

Creatine use is widespread in high school football players. High school football players who use creatine may not be aware of the risks and benefits associated with creatine supplementation. Sports medicine professionals who work with this population need to educate athletes, coaches, and parents about the use of creatine as a performance-enhancing supplement.

Effect of age on electrical field stimulation (EFS)-induced endothelium-dependent vasodilation in male and female rats

OBJECTIVE

The purpose of this study was to determine whether the effect of age on electrical field stimulation (EFS)-induced endothelium-dependent vasodilation was different in males and females.

METHODS

Young (3 month) and old (25 month) Fisher 344 rats were studied: young females (YF, n=34), young males (YM, n=28), old females (OF, n=19), and old males (OM, n=24). Isolated mesenteric resistance arteries (endothelium-intact and denuded) were pressurized, and outer diameter was monitored. EFS-response curves (0.1-8 Hz) were performed in preconstricted arteries in the presence of guanethidine. EFS responses were expressed as percent relaxation from preconstricted diameter. Area under the curve (AUC) was calculated and comparisons were made using ANOVA and t-tests.

RESULTS

Males became less responsive to EFS-induced vasodilation with age, while responses among females were unaffected (AUC: YM=344+/-23, OM=253+/-25, P=0.008; YF=397+/-21, OF=365+/-25, P=0.33). Endothelial denudation produced a significant decrease in EFS-induced dilation among all rat groups. The effect of denudation was greater in young animals compared to old. Incubation with the nitric oxide synthase inhibitor N(omega)-nitro-L-arginine (LNA) significantly decreased EFS responsiveness among all of the rat groups.

CONCLUSIONS

EFS-induced vasodilation declines with age among males. In YF and YM endothelium-dependent EFS-induced vasodilation is mediated by the release of endothelium-derived NO. With age, endothelial function declines, which is likely due to a decrease in the production of endothelium-derived NO. A decline in endothelial-derived NO is likely responsible for the decrease in EFS-induced vasodilation with age among males.

Gender differences in the effect of age on electrical field stimulation (EFS)-induced adrenergic vasoconstriction in rat mesenteric resistance arteries

The objective of this study was to examine the effects of gender and age on electrical field stimulation (EFS)-induced vasoconstriction. Fisher 344 rats were studied: young females (YF, n = 38), young males (YM, n = 29), old females (OF, n = 33), and old males (OM, n = 30). Isolated mesenteric resistance arteries (endothelium-intact or denuded) were pressurized, and outer diameter was monitored. Dose-response curves were performed to KCl and phenylephrine (PE). EFS (0.1-16 Hz) responses were expressed as percentage of constriction from baseline. Area under the curve (AUC) was calculated and comparisons were made using analysis of variance and t tests. Females became less responsive to EFS-induced constriction with age, whereas constrictor responses among males were unaffected (AUC: YF = 454 +/- 15, OF = 284 +/- 22, p < 0.001; YM = 391 +/- 35, OM = 357 +/- 31, p = 0.22). Endothelial denudation produced a significant increase in EFS-induced constriction in OF and OM. Endothelium removal in OF increased the EFS constrictor response to the level seen in arteries from YF. BQ 123 (ET(A) receptor antagonist) significantly decreased EFS-induced constriction in YM and OM. In YM, SQ 29,548 [thromboxane A(2) (TXA(2))/PGH(2) receptor antagonist] and indomethacin depressed constrictor responses. There were no differences among groups in the sensitivity to KCl, but YF were the most sensitive to PE. In conclusion, EFS-induced vasoconstriction declined with age among females but not males. The decrease in EFS constrictor responses in OF may be due to a selective decrease in vascular smooth muscle sensitivity to adrenergic agonists and an increase in the production of an endothelium-derived vasodilator. Among males there is also an endothelin-1 and TXA(2)/PGH(2) component to EFS-induced constriction that is absent among females.

Cross-validation of methods to predict body fat in African-American and Caucasian collegiate football players

Eight skinfold (SF) equations and bioelectrical impedance analysis (BIA) were cross-validated in 71 Division IA college football players. Criterion percent body fat (%FAT) was determined by hydrostatic weighing (HW) and computed from body density (BD) for African Americans (n = 28) and Caucasians (n = 43). Results were analyzed by method, with position and race effects examined simultaneously using a two-way ANOVA. Analysis included computation of mean difference (MD), correlation (r), standard error of estimate (SEE), and total error (TE). Skinfolds had MDs ranging from -1.8 to 2.9%, correlations from .85 to .93, SEEs from 2.3 to 3.2%, and TEs from 2.3 to 4.2%. Bioelectrical impedance analysis was significantly different from HW and yielded the highest MD (3.8%), lowest correlation (r = .78), highest SEE (3.9%), and highest TE (5.4%). The Jackson and Pollock (1978) SF equation provided the most valid prediction of HW-determined %FAT in a racially mixed sample of college football players, demonstrating the highest correlation, lowest SEE and TE, and an intercept and slope not significantly different than 0.0 and 1.0, respectively.

Prediction of percent body fat in adult males using dual energy x-ray absorptiometry, skinfolds, and hydrostatic weighing

The purpose of this study was to compare the prediction of percent body fat (%FAT) by dual energy x-ray absorptiometry (DXA), skinfolds (SF), and hydrostatic weighing (HW) in adult males. Subjects were 35 adult male Caucasians (mean +/- SD; age: 39.1 +/- 14.0 yr, height: 180.6 +/- 5.3 cm, weight: 81.0 +/- 11.1 kg). %FAT, determined by HW with residual volume determined via O2 dilution, served as the criterion. DXA %FAT was determined by the Norland XR-26 (XR-26) bone densitometer and by the SF equations of Jackson and Pollock (JP) (1978), and Lohman (LOH) (1981). Criterion referenced validation included analyzing mean (+/- SD) %FAT values using a one-way ANOVA for significance, comparison of mean differences (MD), correlations (r), standard error of estimates (SEE), and total errors (TE). Significant differences were found between means of each method. The r (0.91) and SEE (3.0 %FAT) for DXA compare favorably with the established SF methods of JP and LOH for predicting %FAT; however, DXA demonstrated the largest MD (3.9 %FAT) and TE (5.2 %FAT). Regression analysis yields HW = 0.79* DXA + 0.56. The results do not support earlier research that found no significant difference between HW and DXA %FAT in males. The study suggests the density of the fat-free body (DFFB) is not constant, and that the variation in bone mineral content affects the DFFB, which contributes to the differences between DXA and HW %FAT. We recommend further research to identify inconsistencies between manufacturers of DXA equipment in prediction of %FAT in males.

A comparison of methods to predict minimal weight in high school wrestlers

The purpose of this study was to compare the accuracy of body fat determinations and subsequent calculation of minimal weight (MW) by dual energy x-ray absorptiometry (DEXA), bioelectrical impedance (BIA), near-infrared photospectometry (NIR), and anthropometry (LOHMAN). Necessitated by mandatory state minimal weight testing, the methods were cross-validated on 95 Wisconsin high school wrestlers (mean +/- SD; age: 15.1 +/- 1.2 yr, height: 170.4 +/- 7.1 cm, weight: 63.4 +/- 9.8 kg). MW, defined as fat-free body/0.93, determined by hydrostatic weighing (HW) and residual volume via O2 dilution, served as the criterion. The validity of the four selected MW predictions were evaluated against HW by examining mean differences (MD), standard deviation differences (SDD), correlations (r), standard error of estimate (SEE), and total errors (TE). Statistically significant differences were shown between the methods and the criterion by t-tests; however, these were clinically small in Lohman (0.6 kg) and BIA (0.9 kg). TE ranged from 2.25 kg (Lohman) to 6.03 kg (NIR). The results indicated that Lohman skinfold equation provided the most accurate prediction of MW, demonstrating the highest correlation (0.972), lowest MD (0.6 kg), lowest SEE (2.12 kg), and lowest TE (2.25 kg) of the methods evaluated.

Oxidation of Formatopentaamminecobalt(III) Perchlorate by Silver(II)

Formatopentaamminecobalt (III) perchlorate is oxidized relatively rapidly by AgO in acid conditions (1 M H2SO4, HNO3 or HO3SCF3), with approximately 97% of the total cobalt retained in the cobalt(III) state as [Co(NH3)5(OH2)]3+ and [Co(NH3)5X]n+ (X = SO42- or NO3-). A combination of product distribution, silver(I) and silver(II) concentration dependence and 18O-labelling experiments indicate that the major pathway (97%) is oxidation of [Co(NH3)5(OCHO)]2+ directly to [(NH3)5Co(OCO)]3+ and [(NH3)5Co(O2COH)]2+ by AgIII (through the disproportionation 2AgII ↔ AgIII + AgI ) in a relatively rapid hydride extraction. A minor path (3%) appears to involve a one-electron oxidation by AgII to the complexed radical anion [(NH3)5Co(OC?O)]2+ which then decays intramolecularly to yield CoII and CO2. In 1 M H2SO4 the cobalt(III) intermediate, [(NH3)5Co(OCO)]3+, has been shown by 18O-labelling and competition experiments to decay by dissociation into [Co(NH3)5]3+ and CO2. The pentacoordinate intermediate [Co(NH3)5]3+ immediately captures OH2 and HSO4-.

Clients' satisfaction survey in a psychiatric inpatient population attached to a general hospital

A clients' satisfaction survey was undertaken on the population of a psychiatric inpatient facility in a general hospital setting. The responses were analysed statistically and the results showed that the patients were highly satisfied with the services provided. The results are reviewed within the context of the literature available, and the methodological issues involved are discussed. It is felt that existing questionnaires need to be further refined to make them more sensitive to dissatisfaction felt by patients.

Lymphoma and the parotid gland

The rich parotid lymphatic network makes necessary the inclusion of benign and malignant lymphoid disease in the differential diagnosis of parotid swelling. This area is affected directly by lymphoma in many clinical situations and has an indirect relationship with lymphoma through Sjögren's syndrome. These associations can produce uncertainty about the etiology and significance of parotid masses. Patients with Sjögren's have a spectrum of lymphoproliferative disorders from benign lymphoepithelial disease (BLD) to lymphoma and a significantly greater incidence of the latter than the general population. Nine patients with lymphoma and also benign and malignant lymphoid disease in the parotid illustrate various diagnostic considerations. These include that both benign and malignant parotid lymphoid pathology are seen with systemic lymphoma, that lymphoma can co-exist with BLD, may be misdiagnosed as BLD, and can develop in the same gland after appearance of BLD.

Male aggression toward females as a function of traditional vs nontraditional cues and visibility of the target

An aggression paradigm, disguised as a competitive reaction time task, was designed to investigate aggression by males toward a female who deviated from traditionally expected properties of a female target. 33 male subjects, exposed to a female varying in traditional vs non-traditional appearance and attitudes, did not set differential shock levels for their target. The surprisingly high shock levels which subjects set for the female, however, resulted in an additional experimental condition to compare the visibility of the opponent in the design with the non-visibility of female opponents in previous studies demonstrating low aggression against females. Seven subjects with a non-visible target shocked their opponent significantly less than in all other conditions where males had contact with the female opponent. This finding suggests that studies using non-visible female targets cannot legitimately be generalized to real-life situations and that males may not be inhibited from aggressing against females as previously thought.

The effects of N-hexyl-O-glucosyl sphingosine on normal cultured human fibroblasts: a chemical model for Gaucher's disease

Normal human skin fibroblasts were grown in the presence of N-hexyl-O-glucosyl sphingosine (HGS), an inhibitor of aryl glucosidase and glucocerebrosidase. Tests of the cells with aryl glycosides showed that beta-glucosidase activity in the cells was drastically reduced while other enzyme activities (alpha-glucosidase, beta-galactosidase, and N-acetyl-beta-hexosaminidase) were normal or elevated. Exposure of cells to HGS for 28 days resulted in increased values for cell weight per plate, glucocerebroside concentration, and galactosyl-galactosylglucosyl ceramide concentration. The concentrations of total lipid, cholesterol, and protein were unchanged, as was the fatty acid distribution within the glycolipids. Chemically, the inhibitor-treated cells exhibited a model form of Gaucher's disease. Although many membranous cytoplasmic inclusions were induced by HGS, they were unlike the characteristic inclusions seen in individuals with the genetic disorder. Skin fibroblasts from a Gaucher patient showed no abnormalities in composition or appearance.

Study of the Hurler syndrome using cell culture: definition of the biochemical phenotype and the effects of ascorbic acid on the mutant cell

Fibroblasts from patients with Hurler syndrome retain a distinctive biochemical phenotype when grown in culture which is characterized by increased synthesis of both nonsulfated and sulfated glycosaminoglycans. Ascorbic acid reinforces the phenotypic expression of the biochemical abnormality, producing not only increased synthesis of sulfated glycosaminoglycans, but selective retention of sulfated glycosaminoglycans within the cell. Although the synthesis of nonsulfated glycosaminoglycans is also increased, these compounds, particularly hyaluronic acid are not retained by the cell but are secreted into the medium. Analyses of urine from patients with Hurler syndrome show increased absolute concentrations of nonsulfated glycosaminoglycans in addition to the expected increase in sulfated glycosaminoglycans. This indicates that the biochemical phenotype as defined in cell culture is not an artifact of the experimental model but reflects the biochemical defect in the patient. Redefinition of the biochemical defect to include nonsulfated as well as sulfated glycosaminoglycans contradicts explanations of this disease which are based on a single structural gene mutation.

Ascorbic acid deficiency in cultured human fibroblasts

Fibroblasts grown in medium containing less than 1 microg of ascorbic acid per milliliter showed evidence of ascorbic acid deficiency when compared with cells grown in medium containing 50 microg of ascorbic acid per milliliter. This was manifested morphologically by dilated endoplasmic reticulum, a decrease in number, size, and intensity of staining of the mitochondria, by defective intercellular fibril formation, and by easy disaggregation of the cells from the intercellular matrix after treatment with pronase. When 50 microg per milliliter of ascorbic acid was incorporated into the medium, the altered morphology was corrected, banded fibrils were produced which were organized into bundles, and the cells were tightly bound in a matrix which was resistant to disaggregation with a variety of proteolytic enzymes. Collagen and sulfated glycosaminoglycan synthesis were less in the control than in the ascorbic acid supplemented cells. Similar morphological and chemical changes have been reported in the connective tissue of scorbutic animals. The effects of low ascorbic acid concentration on fibroblasts in culture indicate that these cells require ascorbic acid to maintain connective tissue functions.

Vitamin C-induced increase of dermatan sulfate in cultured Hurler's fibroblasts

In fibroblasts taken from patients witli Hurler's syndromne and grown in cultlure, dermatan sulfate constituted a larger percentage of the total sulfated glycosaminoglycans than it did in cultured fibroblasts from unaffected individuals. Moreover, the addition of ascorbic acid (vitamnin C) to the culture medium markedly increased the concentration of dermatan sulfate in the Hurler's fibroblasts but not in the normal fibroblasts. The biochemical phenotype of the Hurler's cells persisted during 28 weeks of serial culture.