Are skin equipment for assessing childhood eczema any good?

AIM

Symptomatology and severity of atopic dermatitis (AD) can be objectively measured with equipment. This study aimed to compare skin measurements and investigate their correlations with various clinical severity scores.

METHODS

Skin hydration (SH), transepidermal water loss (TEWL), pH, erythema, pigmentation, and ITA (individual typology angle) were measured (using Delfin, Courage + Khazaka, and Mettler Toledo equipment), and correlated with Patient-Oriented Eczema Measure (POEM, a short-term subjective-symptom score), Scoring Atopic Dermatitis (SCORAD, a short-term subjective-symptom and objective-sign score), Nottingham Eczema Severity Score (NESS, a long-term subjective-symptom score), Children Dermatology Life Quality Index (CDLQI, a short-term subjective-symptom score) with Spearman's rho coefficient.

RESULTS

80 sets of clinical scores from eczema patients (mean age: 10.8 ± 4.9 years; 44.6% male) were evaluated. The POEM, objective SCORAD, CDLQI correlated well with each other. Skin pH ranged from 4.3 to 7.0 (mean 5.7 ± 0.61). Skin pH was correlated with Objective SCORAD components, including area (rho = 0.269, p = .036), erythema (rho = 0.302, p = .018), and lichenification (rho = 0.365, p = .026) and with the usage frequency of topical antibiotics. Skin pH was also correlated with other skin measurements, including SH (Delfin equipment: rho = -0.38, p < .001). SH and TEWL as measured by Delfin equipment correlated better with a number of symptoms and signs than Courage + Khazaka equipment. Other clinical measurements including erythema, melanin, and skin color did not demonstrate strong correlations with clinical symptom scores.

CONCLUSION

Skin pH (using Mettler Toledo), SH, and TEWL (using Delfin equipment) correlated well with various clinical symptomatology scores. Less acidic pH appears to be associated with worse clinical scores of symptomatology, and increase usage of topical antibiotics, These findings not only support the supplementary usage of equipment in aiding objective documentation of clinical symptomatology in eczema therapeutic research but also the advocacy of maintaining more acidic skin and avoiding alkaline soap and emollient products.

Age, sex, and disease status as determinants of skin hydration and transepidermal water loss among children with and without eczema

PURPOSE

Skin hydration (SH) and transepidermal water loss (TEWL) are important skin biophysical parameters for assessment of childhood eczema. This study investigated whether age, sex, and disease status influence these parameters.

METHODS

Skin hydration and TEWL were measured by Delfin MoistureMeterSC and Delfin Vapometer SWL5, respectively, among children aged ≤18 years with and without eczema. Disease status was evaluated using Scoring Atopic Dermatitis (SCORAD) and Nottingham Eczema Severity Score (NESS) clinical tools.

RESULTS

Clinical scores and objective measurements were reviewed for 132 patients with eczema and 120 patients without eczema. In both sexes, SH was significantly higher among children aged ≤2 years with and without eczema than among children aged >2 years with and without eczema. Among children aged >2 years, SH was higher among girls with and without eczema than among boys with and without eczema. Regardless of age or sex, SH was lower among children with eczema than among children without eczema. Age-, sex-, and disease-related differences were not observed for TEWL. Skin hydration was negatively correlated with objective SCORAD (r=-0.418, P<0.001), overall SCORAD (r=-0.385, P<0.001), oedema/papulation (r=-0.243, P=0.041), lichenification (r=-0.363, P=0.002), dryness (r=-0.415, P<0.001), and intensity (r=-0.266, P=0.025). Transepidermal water loss was positively correlated with objective SCORAD (r=0.209, P=0.018), overall SCORAD (r=0.215, P=0.015), and lichenification (r=0.240, P=0.043). Skin hydration was negatively correlated with TEWL among children without eczema (r=-0.401, P<0.001), but not among children with eczema.

CONCLUSION

Skin hydration can be used to distinguish clinical differences in eczema based on age, sex, and disease status.

Assessment of adherence to eczema treatment in Hong Kong children

Introduction: Eczema is the most common childhood skin problem in Hong Kong. Treatment adherence is crucial in symptom management and the effectiveness of eczema management. The Problematic Experiences of Therapy Scale (PETS) is used to assess adherence to treatment among children with eczema. Objective: This study examined the psychometric properties of the translated Chinese version of PETS (C-PETS) among parents and caregivers of children with eczema. Methods: PETS was translated into Chinese and data obtained from a convenience sample of 147 Chinese participants from a regional hospital in Hong Kong. Results: The internal consistency of C-PETS with a Cronbach's α of 0.93 and good test-retest reliability with weighted Kappa ranging from 0.74 to 0.89 were obtained. Significant positive correlations were found among the C-PETS, Children's Dermatology Life Quality Index (r = 0.25, p = .002), and Severity Grading of Atopic Dermatitis scores (r = 0.38, p = .001). A significant negative correlation was found between C-PETS and Chinese adaptation of Generic Self-Efficacy scale (r = -0.40, p = .001). Confirmatory factor analysis showed that the data supported the structural validity of C-PETS. Conclusion: This study indicates that C-PETS is a reliable and valid measure to evaluate treatment adherence for Chinese parents and caregivers of children with eczema.

Two adult galactosaemia females with normal ovarian function and identical GALT mutations (Q188R/R333G)

We report two unrelated cases of adult galactosaemia females with normal ovarian function and Q188R/R333G mutations. Clinical history has been followed for 40 years. Biochemical finding in one patient are consistent with the presence of small amounts of galactose-1-phosphate uridyltransferase (GALT) activity, which differs from classical galactosaemia.

A case-control study of galactose consumption and metabolism in relation to ovarian cancer

Consumption or metabolism of dairy sugar and ovarian cancer have been linked based on evidence that galactose may be toxic to ovarian germ cells and that ovarian cancer is induced in animals by depletion of oocytes. We assessed consumption of dairy products and obtained blood for biochemical and molecular genetic assessment of galactose metabolism in 563 women with newly diagnosed epithelial ovarian cancer and 523 control women selected either by random digit dialing or through lists of residents in eastern Massachusetts and New Hampshire. We observed no significant differences between cases and controls in usual consumption of various types of dairy products or total daily lactose (the principal source of galactose in the diet); nor did we find that RBC activity of either galactose-1-phosphate uridyl transferase (GALT) or galactokinase differed. The mean (and SE) activity of uridine diphospho-galactose 4'-epimerase (in micromoles per hour per gram of hemoglobin) was, however, significantly lower (P < 0.005) in cases compared with controls, 20.32 (0.31) versus 21.64 (0.36). Ovarian cancer cases were also more likely to carry the N314D polymorphism of the GALT gene, generally predisposing to lower GALT activity. The difference was most evident for endometrioid and clear cell types of ovarian cancer, in which 3.9% of cases were found to be homozygous for N314D compared with 0.4% of controls, yielding an odds ratio and 95% confidence interval of 14.17 (2.62-76.60). We conclude that, whereas adult consumption of lactose carries no clear risk for the disease, certain genetic or biochemical features of galactose metabolism may influence disease risk for particular types of ovarian cancer.

Molecular and biochemical basis of galactosemia

Galactosemia is a clinically heterogeneous autosomal recessive inborn error of metabolism caused by deficiency of galactose-1-phosphate uridylyltransferase (GALT). Despite the numerous point mutations identified in the GALT gene, the prevalence of these mutations in different ethnic groups has not been studied. Reports on genotype/phenotype correlation are not consistent due to the small sample sizes studied and the lack of a sensitive enzyme assay. We applied multiplex PCR/ASO dot blot analysis to screen 293 galactosemic patients for 17 known point mutations in exons 5, 6, and 10. Our data demonstrate that only 7 of these mutations were detected in our patients, accounting for 65% of the GALT mutant alleles. Although Q188R is the most common mutation in Caucasian and Hispanic patients, the S135L mutation is most common in African-Americans. Another mutation, F171S, was observed only among African-American patients. An improved, sensitive, and accurate method was used to measure GALT activity in patient's red blood cells. The results indicated that patients homozygous for Q188R have no enzyme activity while those homozygous for S135L had residual enzyme activity. Interestingly, both Q188R/S135L and S135L/F171S compound heterozygotes demonstrated zero enzyme activity. Overall, 85% of Q188R compound heterozygotes also did not have any enzyme activity, whereas the remaining Q188R and the majority of S135L compound heterozygotes expressed variable amounts of GALT activity. We speculate that heterodimeric subunit interaction plays an important role in determining the overall enzymatic activity. Various genotypes thus result in biochemical and clinical heterogeneity among the patients.

Endometriosis associated with the N314D mutation of galactose-1-phosphate uridyl transferase (GALT)

To explore a possible connection between endometriosis, Müllerian anomalies, and possession of the N314D allele of the gene for galactose-1-phosphate uridyl transferase (GALT), we studied 33 women with endometriosis attending a fertility clinic. Patients completed questionnaires and had DNA tested for the N314D mutation of GALT. A previously completed general population survey of 111 women which obtained the same information was available for comparison. Women with endometriosis were more likely to carry at least one N314D allele (30% compared with 14%) and more likely to report a medical history of scoliosis (21% compared with 2%) compared to general population controls: two features we have described in women with vaginal agenesis. Compared with endometriosis cases without the N314D allele, those cases with the allele tended to have more advanced disease and a family history of endometriosis. We speculate that endometriosis may arise due to defects of canalization of the cervix leading to cervical stenosis and retrograde menstruation. The relevance of the N314D mutation, via this model, may derive from an association between abnormalities of galactose metabolism and vaginal agenesis which represents a canalization defect of the vaginal plate of the Müllerian tubercle, the same structure which gives rise to the cervix.

Radiochemical assay of minute quantities of galactose-1-phosphate uridyltransferase activity in erythrocytes and leukocytes of galactosemia patients

A sensitive radioisotopic method has been developed which can detect galactose-1-phosphate uridyltransferase (GALT) activity as low as 0.1% of normal control values in both erythrocytes and leukocytes. This assay utilizes carbon-14 labeled galactose-1-phosphate with high specific activity and requires removal of endogenous galactose-1-phosphate (Gal-1-P) and uridine diphosphate glucose (UDPGlc) through dialysis. Optimal exogenous UDPGlc concentration has been determined with a fixed concentration of Gal-1-P in the incubation. The rate of product, uridine diphosphate galactose (UDPGal), formation is monitored at three different times. Among 423 patients with galactosemia studied by this method, 363 patients exhibited no detectable GALT activity in their erythrocytes and 60 patients were found to have detectable erythrocyte GALT activity ranging from 0.02 to 5.0 units normal values: > 20 units). The former group of patients was designated as classic galactosemia (GG) and the latter group as galactosemia variant (GV). Leucocytes from ten patients belonging to the GG group also showed complete absence of GALT activity while leukocytes from two patients belonging to the GV group showed GALT activity at levels comparable with those found in their erythrocytes. Because there is extensive biochemical heterogeneity among galactosemia patients, we recommend that an assay with increase sensitivity be carried out on blood samples from galactosemia patients so that clinical, biochemical and molecular correlations made by different groups of investigators can be compared.

Biochemical and molecular studies of 132 patients with galactosemia

We evaluated 132 galactosemia patients for the Q188R (glutamine-188 to arginine) mutation in the human galactose-1-phosphate uridyltransferase (GALT) gene and for GALT activity in their hemolysates by a sensitive radioisotopic method. In those without any detectable GALT activity (GG), the Q188R mutation constituted 67% of the alleles. In patients with detectable GALT activity (GV), only 16% of the alleles were accounted for by Q188R. In all patients who were homozygous for the Q188R mutation, no erythrocyte GALT activity could be demonstrated. There was an extensive variation in the amount of detectable GALT activity ranging from 0.1% to 5% of the normal values among the GV patients. There was a difference in the frequency of Q188R mutation in the GALT alleles among patients belonging to different racial and ethnic groups. In Caucasian and Hispanic patients, the frequency was not far different (64% and 58%, respectively). On the other hand, only 12% of the GALT alleles with Q188R were found in African-American patients.

Characteristics of women with a family history of ovarian cancer. I. Galactose consumption and metabolism

BACKGROUND

Galactose metabolism may be a risk factor for ovarian cancer based upon evidence that galactose causes ovarian failure and that ovarian cancer arises from premature ovarian failure. This study examines galactose-1-phosphate uridyl transferase (GALT) activity in women with a family history of ovarian cancer (FOC) to determine if low GALT activity occurs in women who are at risk for but in whom ovarian cancer has not yet developed.

METHODS

The authors studied 106 premenopausal women (FOC patients) with one primary or two second-degree relatives with ovarian cancer compared with 116 age matched control subjects without a family history of ovarian cancer (FOC controls). All women completed questionnaires and had blood drawn to measure GALT activity and genotype.

RESULTS

Mean erythrocyte GALT activity, in micromoles of hexose conversion per hour per gram of hemoglobin was 21.5 in FOC patients, significantly lower than the mean of 23.1 observed in FOC control subjects, (P = 0.001). FOC patients more frequently displayed the Duarte variant of galactosemia as detected by electrophoresis. In a subset of 87 patients and 113 control subjects for whom DNA was available, the allelelic frequency of the Duarte variant based upon molecular genetic detection of the N314D mutation that is associated with the Duarte variant was 15.5% among FOC cases compared with 7.5% among control subjects (P < 0.02). Galactose consumption did not differ between FOC patients and control subjects.

CONCLUSION

Galactose metabolism differs between women with and without a family history of ovarian cancer, suggesting that it may be a genetic risk factor for ovarian cancer, possibly mediated through oocyte toxicity from galactose.

Correlation of cognitive, neurologic, and ovarian outcome with the Q188R mutation of the galactose-1-phosphate uridyltransferase gene

This study was conducted to determine whether there is a genotype/phenotype correlation between aspects of cognitive, neurologic, and ovarian outcome in patients with galactosemia and the Q188R mutation of the galactose-1-phosphate uridyltransferase gene. The results showed that the Q188R mutation was found in 72% of alleles: 38 patients were homozygous and 21 were heterozygous for Q188R; eight patients did not have the mutation. The mean Broad Cognitive score for the group homozygous for Q188R was 75 (SD = 16), which was not statistically different from the outcome for the heterozygous group (mean score, 67; SD = 25) or the negative group (mean score, 88; SD = 21). Tremor, ataxia, and dysmetria were found in 12 subjects, and there was no association with Q188R status. Similarly, there was no association of this mutation with the development of primary amenorrhea (8 subjects) versus secondary amenorrhea (found in 14 women). Our findings suggests that the variability of outcome for patients with classic galactosemia cannot be explained by Q188R status alone, at least with regard to cognitive functioning, presence of neurologic symptoms, and timing of the onset of ovarian failure.

On the molecular nature of the Duarte variant of galactose-1-phosphate uridyl transferase (GALT)

Galactosemia is an inborn error of galactose metabolism secondary to deficiency of galactose-1-phosphate uridyl transferase (GALT). GALT is a polymorphic enzyme and Duarte (D) is the most common enzyme variant. This variant is characterized by faster electrophoretic mobility and reduced activity. Duarte/galactosemia compound heterozygotes (D/G) are commonly identified in galactosemia newborn screening programs. However, these patients do not generally require treatment. By using a "candidate mutation" approach to define the molecular basis of the Duarte variant of GALT, a close association between the previously reported N314D polymorphism and the Duarte variant of GALT was found. We suggest that N314D encodes the D variant of GALT and that molecular testing for N314D might be useful to confirm a biochemical diagnosis of Duarte variant of GALT.

Neurologic complications in galactosemia

Two siblings, a 27-year-old man and his 24-year-old sister were diagnosed with classic transferase deficiency galactosemia at birth and were treated with strict lactose restriction. Despite well-documented dietary management, both siblings are mentally retarded and manifest a progressive neurologic condition characterized by hypotonia, hyperreflexia, dysarthria, ataxia, and a postural and kinetic tremor. Magnetic resonance imaging revealed moderate cortical atrophy, a complete lack of normal myelination, and multifocal areas of increased signal in the periventricular white matter on T2-weighting. These patients suggest that even with early diagnosis and treatment, individuals with galactosemia may have significant neurologic morbidity with abnormalities of white matter development. This finding raises the possibility of biochemical heterogeneity within the classic transferase deficiency group, as well as the possibility of a lack of available galactose metabolites necessary for glycolipid synthesis causing a disruption of normal myelin development.

Galactose consumption and metabolism in relation to the risk of ovarian cancer

In a case-control study, consumption of dairy foods by 235 white women with epithelial ovarian cancer and by 239 control women, and activity of red blood cell galactose-1-phosphate uridyl transferase (transferase) in a subset of 145 cases and 127 controls were determined. Yogurt was consumed at least monthly by 49% of cases and 36% of controls. The mean transferase activity of cases was significantly lower than that of controls. When a ratio of lactose consumption to transferase (L/T) was calculated, cases had a mean L/T of 1.17 compared with 0.98 for controls; there was a highly significant trend for increasing ovarian cancer risk with increasing L/T ratio. Lactose consumption may be a dietary risk factor and transferase a genetic risk factor for ovarian cancer.

Galactose-1-phosphate uridyl transferase activity associated with age at menopause and reproductive history

Reproductive history was obtained and the activity and electrophoretic pattern of the blood enzyme galactose-1-phosphate uridyl transferase (transferase) was measured in 104 adult Caucasian women, less than 70 years of age, sampled from the general population. Fifteen women were identified as carriers for the Duarte (GtD) or galactosemia (gt) variants of transferase--genes associated with reduced transferase activity compared with normal (Gt+). The mean age at menopause for 8 women with a natural menopause who were GtD/Gt+ or gt/Gt+ was 44.8, significantly younger (P = 0.007) than the mean age of 49.2 reported by 31 naturally postmenopausal subjects with Gt+/Gt+ genotypes and normal transferase activity. Compared with the latter group, women who were Duarte or galactosemia carriers were 13.7 times more likely to have a menopause before age 48 (with 95% confidence limits of 2.0 to 95.5). Six of 13 (46%) married women who were GtD/Gt+ or gt/Gt+ reported more than 2 years' trying to achieve a pregnancy, compared with 11 of 74 (15%) with normal genotypes and activity (P = 0.02). The authors conclude that genetic deficiency of transferase may be associated with infertility and early menopause.

Gonadal function and ovarian galactose metabolism in classic galactosemia

Evaluation of ovarian steroid secretion, histologic examination of ovarian tissue, and incubation studies with radiolabelled galactose in ovarian tissue slices were performed in a 21-year-old woman with galactosemia and incipient ovarian failure. After exogenous gonadotropin administration in an attempt to achieve fertility, there was no evidence of ovulation by ultrasound; estrogen and androgen production were deficient indicating ovarian unresponsiveness. Histologic examination of the ovary revealed that the ovarian stroma had an increase in fibrous tissue and that a few hyalinized atretic follicles were present with no intermediate or evolving Graafian follicles. After incubation with galactose-1-14C, there was absence of labelled CO2 production and only labelled galactose-1-phosphate was identified as compared to controls in which several labelled intermediates could be seen. The incorporation of galactose into the TCA-insoluble fraction was drastically reduced in the patient compared to controls, suggesting that there may be a deficiency of ovarian galactose-containing glycolipids, glycoproteins and mucopolysaccharides in the galactosemic ovary. Deficiency in the production of galactose containing compounds, or galactose-1-phosphate accumulation or both, may lead to the development of hypergonadotropic hypogonadism seen in women with galactosemia.

Galactose metabolism in human ovarian tissue

Galactose metabolism was studied in human ovarian tissue obtained from 14 women controls between 21 and 72 y of age, and one 21-y-old galactosemic patient with hypergonadotrophic hypogonadism. Tissue slices were incubated with 1-14C-galactose, and labeled intermediates were analyzed by anion-exchange column chromatography. Activities of enzymes related to the galactose pathway: galactokinase, transferase, epimerase, uridine diphosphoglucose (UDPGlc) and uridine diphosphogalactose pyrophosphorylases, and UDPGlc and uridine diphosphogalactose pyrophosphatases were measured in ovarian homogenates using radioisotopic, spectrophotometric, and fluorometric techniques. Incorporation of carbon label from 1-14C-galactose into various galactose and glycolytic intermediates, as well as carbon dioxide and TCA-insoluble materials was demonstrated in samples from non-galactosemic controls. In tissue from the galactosemic individual, no labeled carbon dioxide was produced and very little incorporation into TCA-insoluble material was found. Labeled galactose-1-phosphate was elevated. In normal ovarian tissue, specific activities of galactokinase, transferase, epimerase, and UDPGlc pyrophosphorylase are much higher than those found in the red cells and in testes. UDPGlc pyrophosphorylase activity is about 50 times that of transferase, suggesting that uridine nucleotide sugars have an important role in the normal development and function of the ovary. It is hypothesized that premature ovarian failure, often observed in patients with galactosemia, is due to interference with nucleotide sugar metabolism and the synthesis of galactose containing glycoproteins and glycolipids consequent to the enzymatic defect in the major pathway of galactose metabolism.

Deficit of uridine diphosphate galactose in galactosaemia

The levels of uridine diphosphate galactose (UDPGal) and uridine diphosphate glucose (UDPGlc) have been determined in liver autopsy samples, erythrocytes and cultured skin fibroblasts from galactosaemic patients and compared to non-galactosaemic controls. In patients with undetectable erythrocyte galactose-1-phosphate uridyltransferase (transferase) activity, the levels of UDPGal were substantially lower than in controls. In patients with detectable transferase activity, even though in less than 1% of normal values, both UDPGal and UDPGlc levels were in the normal range. Incubation of erythrocytes from both galactosaemic patients and normal individuals with 10 mmol/L uridine increased UDPGal and UDPGlc levels several-fold, both in the presence or absence of galactose in the incubation medium. We hypothesize that a deficit of UDPGal is responsible for the late onset clinical manifestations in galactosaemia which include ovarian failure, speech defect and neurological abnormalities. We suggest that uridine administration may be of therapeutic value in raising the intracellular concentrations of UDPGal. We conclude that the transferase reaction, however small in activity, is essential for optimal UDPGal formation.

Uridine nucleotide sugars in erythrocytes of patients with galactokinase deficiency

The levels of UDPglucose and UDPgalactose (UDPGal) have been measured in erythrocytes of seven patients with galactokinase deficiency. Normal levels of UDPGal were found in all patients with galactokinase deficiency (McKusick 23020). This is in contrast with reduced values of UDPGal found in patients with classical galactosaemia who have complete absence of galactose-1-phosphate uridyl transferase activity. It was demonstrated that patients with galactokinase deficiency had an incomplete enzyme block in erythrocytes by direct enzyme assay, by 14CO2 production from [1-14C]galactose, and by the appearance of labelled intermediates, notably galactose-1-phosphate and UDPhexose.

Lysosomal enzyme activities among Chinese: leukocyte alpha-galactosidase and beta-galactosidase

alpha-Galactosidase and beta-galactosidase activities have been determined in leukocyte preparations from 100 randomly selected Chinese adults. For alpha-galactosidase, two groups with low activities were identified: group I consisted of 3 females having activities below 40% of normal, and group II consisted of 5 males and 1 female with activities about 60% of normal. Family studies suggested that these low alpha-galactosidase activities are genetically determined. Only 1 individual was found to have about 50% of normal beta-galactosidase activity; presumably he is a carrier for beta-galactosidase deficiency (GM1 gangliosidosis).

Müllerian aplasia associated with maternal deficiency of galactose-1-phosphate uridyl transferase

The activity and electrophoretic pattern of galactose-1-phosphate uridyl transferase (transferase), a key enzyme in galactose metabolism, were analyzed in four patients with Müllerian aplasia (Rokitansky-Küster-Hauser syndrome) and their mothers. Mothers of two of the patients had genetic variations of their transferase enzymes with activities below the normal range. Affected daughters from these two mothers also had genetic variations of the transferase enzyme. In one of the patients whose Müllerian aplasia had been diagnosed 15 years previously, premature ovarian failure developed. These case reports suggest a possible association between errors of galactose metabolism, Müllerian aplasia, and premature menopause--an association that is supported by a rodent model in which female offspring of mothers fed a high-galactose diet were born with reduced oocyte numbers and delayed vaginal opening.

Methylmalonic and propionic acidemias: lipid profiles of normal and affected human skin fibroblasts incubated with [1-14C]propionate

Normal human skin fibroblasts and those from methylmalonic acidemia and propionic acidemia patients were grown in culture. Following incubation with [1-14C]propionate, the major lipid classes in the cells were separated by thin layer chromatography and isolated fractions analyzed by radio gas chromatography for the presence of odd-numbered long-chain fatty acids; the pattern of even-numbered long-chain fatty acids was obtained also. Normal fibroblasts incorporated a small percentage of propionate into odd-numbered fatty acids which were present in all lipids studied. The abnormal cells incorporated a larger amount while maintaining the characteristic ratios of odd-numbered fatty acids found in the normal line. Most of the radioactivity was associated with phospholipids which are the predominant constituents of cell membranes. A characteristic C15/C17 ratio was found for different phospholipids and the triglyceride fraction; pentadecanoic acid was the principal odd-numbered fatty acid utilized in the assembly of complex lipids. Compared to even-numbered long-chain fatty acids the absolute amount of odd-numbered fatty acids was low (1-2%), even in affected cells. An unusual polar lipid fraction was isolated in the course of the study. In the normal cell it contained several unlabeled eicosanoids which were missing from the same fraction of both affected cell lines.

Pyruvate carboxylase defect: metabolic studies on cultured skin fibroblasts

Oxidative studies using a number of radioactive carbon-labelled substrates on intact cultured skin fibroblasts from a patient with pyruvate carboxylase deficiency revealed dysfunction of the Krebs cycle. The suppression of CO2 production from aspartate but not glutamine strongly suggests that the defective function lies in the aspartate-malate shuttle. Furthermore, there is an unusual dependence on glutamine for the maintenance of growth of the patient's cells compared to normal cells. Glutamine could not be replaced by aspartate supplementation. A secondary defect resulting in accumulation of lipid material was also demonstrated in this study. It is speculated that the intracellular level of oxaloacetate may also be diminished in the patient's cells. Oxaloacetate is primarily generated by the carboxylation of pyruvate catalysed by pyruvate carboxylase.

False-positive amniotic fluid acetylcholinesterase results: the need for a multifacet approach to the prenatal diagnosis of neural tube defects

Two cases are presented with false-positive amniotic fluid alpha-fetoprotein and acetylcholinesterase results for the prenatal diagnosis of neural tube defects. Stage II ultrasound revealed no lesions of the fetal spine in both cases. The alpha-fetoprotein and acetylcholinesterase results returned to normal on subsequent taps. Both pregnancies resulted in normal outcomes. A protocol is presented for managing pregnancies with abnormal alpha-fetoprotein and acetylcholinesterase results.

Beta-glucuronidase deficiency. A heterogeneous mucopolysaccharidosis

We studied two cases of beta-glucuronidase deficiency. One patient's disease was present at birth and the other patient's disease appeared in early childhood. The symptoms observed in both patients, although of differing severity, included peculiar facies, cloudy cornea, hepatosplenomegaly, hernia, kyphosis, recurrent infections, short stature, and developmental delay, as well as increased excretion of urinary chondroitin sulfate A/C and decreased levels of beta-glucuronidase activity. We reviewed all of the reported cases and examined the biochemical and clinical heterogeneity observed in this disorder.

Partial ornithine transcarbamylase deficiency associated with recurrent hyperammonemia, lethargy and depressed sensorium

A 6-year-old boy presented with recurrent coma associated with hyperammonemia and infection is reported. A liver biopsy revealed decreased ornithine transcarbamylase (OTC) activity (16% of normal). The enzymatic abnormality in the child is supported by the finding of elevated orotic acid excretion in his mother following a protein load, compatible with an X-linked pattern of inheritance. Since initiation of a dietary arginine supplement, the child has not had recurrent episodes of hyperammonemia.

Prenatal diagnosis of pseudo arylsulphatase A deficiency

Prenatal diagnosis was performed on a pregnancy at risk for metachromatic leukodystrophy (MLD) in a family with the pseudo arylsulphatase A deficiency trait. Extracts of cultured amniotic fluid cells were deficient in arylsulphatase A indicating that the fetus was either affected with MLD or had the benign pseudodeficiency trait. In the cerebroside sulphate loading test, the at risk cells hydrolysed sulphatide like control cultured amniotic fluid cells implying that the fetus had pseudodeficiency. The pregnancy was carried to term and a male child was delivered. Placenta, urine and fibroblasts had very low activities of arysulphatase A. However, no sulphatide could be detected in urine and growing fibroblasts responded normally in the cerebroside sulphate loading test, suggesting pseudodeficiency. At 29 months, the infant is healthy and shows no stigmata of MLD. The prediction based on the results of the cerebroside sulphate loading test on cultured amniotic fluid cells appeared to be borne out.

Neonatal pyruvate carboxylase deficiency with renal tubular acidosis and cystinuria

This report concerns a patient with severe congenital lacticacidosis associated with proximal renal tubular acidosis and cystinuria. Enzyme studies with cultured skin fibroblasts obtained from the patient revealed zero pyruvate carboxylase activity, but propionyl-CoA carboxylase activity was normal. Administration of various vitamins in large amounts did not improve the clinical condition. In contrast, the patient began to thrive when her diet was supplemented with aspartic acid, asparagine, glutamic acid, and glutamine. The particular dietary treatment used and the biochemical findings merit consideration for management of future cases.

Presymptomatic diagnosis: metachromatic leukodystrophy or pseudo arylsulphatase A deficiency?

Diagnosis of metachromatic leukodystrophy (MLD) was established in the proband at age 27 months. An examination of the family arylsulphatase A profile revealed that the father and younger sibling, age 2 months, had very low enzyme activities like the proband. The father, in all likelihood, had the pseudo arylsulphatase A deficiency trait, but the sibling could be either pseudodeficient or affected with MLD. The fibroblast cerebroside sulphate loading test confirmed that the father had pseudo arylsulphatase A deficiency. The test also indicated that the sibling was affected with MLD. This was confirmed by clinical evidence of neurological degeneration by 18 months.

Radial and linear thin-layer chromatographic prodedures compared for screening urines to detect oligosaccharidoses

We describe a circular (radial) thin-layer chromatographic procedure for separating urinary oligosaccharides. Results were better than those obtained by a single linear development. Bands and specific patterns were finely resolved for various known oligosaccharidoses. The procedure provides a simple means of screening for these disorders.

Radial and linear thin-layer chromatographic prodedures compared for screening urines to detect oligosaccharidoses

We describe a circular (radial) thin-layer chromatographic procedure for separating urinary oligosaccharides. Results were better than those obtained by a single linear development. Bands and specific patterns were finely resolved for various known oligosaccharidoses. The procedure provides a simple means of screening for these disorders.

Regional mapping of the gene for human UDPGal 4-epimerase on chromosome 1 in mouse-human hybrids

Somatic cell hybrids between mouse and human cells containing two different reciprocal translocations involving human chromosome 1, 46,X,t(1;X)(q12;q26) and 47,XX,+21,t(1;17)(p32;p13), were studied for the expression of human uridine diphosphate galactose 4-epimerase (UDPGal 4-epimerase, E.C. 5.1.3.2) by starch-gel electrophoresis. Analysis of the hybrid clones for the expression of the enzyme and the presence of the translocation chromosome 1 has permitted the assignment of the gene for human UDPGal 4-epimerase to the pter yields p32 region of chromosome 1.

Serum pseudocholinesterase variants in Mexican-born patients with lepromatous leprosy

No difference in the distribution of serum pseudocholinesterase variants could be found in lepromatous leprosy patients as compared with controls. The variety of reported relationships of pseudocholinesterase variants in leprosy suggests that only in some populations is a locus regulating pseudocholinesterase genetically linked to a hypothetical locus regulating susceptibility to leprosy.

Biochemical studies of a human low-activity galactose-1-phosphate uridyl transferase variant

A low activity galactose-1-phosphate uridyl transferase (transferase) variant in a newborn infant has been demonstrated by biochemical studies in erythrocytes and cultured skin fibroblasts. The newborn infant was a galactosaemic suspect identified in a neonatal metabolic screening programme. On breast feeding, he did well without clinical symptoms of galactosaemia during the first 15 days of life. However, substantial amounts of erythrocyte galactose-1-phosphate and urinary galactitol corresponding to the levels in untreated galactosaemic patients, along with mild amino aciduria, were found. The transferase activity, as measured by a sensitive micro kinetic radioisotopic method, was about 7--10% of the normal. On starch gel electrophoresis, the enzyme from the haemolysate had similar mobility as the normal in Tris--glycine buffer, pH 8.8 and phosphate buffer, pH 7.0, but had a slower mobility than that of the normal in the histidine buffer, pH 7.8. The mobility difference was much clearer in a semipurified enzyme preparation. The transferase enzyme in the haemolysate appeared to be more heat labile.

Assay of ornithine carbamoyltransferase activity in human liver using carbon-labeled ornithine and thin-layer chromatography

Ornithine carbamoyltransferase (EC 2.1.3.3) activity in human liver homogenates has been measured using 14C-labeled ornithine and unlabeled carbamoyl phosphate. A thin-layer chromatographic (TLC) procedure is used to separate the radioactive substrate and product, ornithine and citrulline, respectively, and the regions of the chromatogram corresponding to ornithine and citrulline are cut out and counted in a liquid scintillation spectrophotometer. The method has the following advantages: (1) the radioactive substrate ornithine is more stable in solution than carbamoyl phosphate, (2) 14C-labeled ornithine is available in higher specific activity than carbamoyl phosphate, (3) all radioactivity may be accounted for by using the TLC system, (4) the developed thin-layer chromatogram is stable indefinitely, (5) in contrast to colorimetric assays, other compounds in the raction mixture do not interfere with the citrulline determination, and (6) most importantly, the rate of the enzyme reaction at various time intervals can be determined by taking aliquots from the same incubation tube.