In Vivo and In Vitro Evaluation of Urinary Biomarkers in Ischemia/Reperfusion-Induced Kidney Injury

Oxidative stress plays an important role in the pathophysiology of acute kidney injury (AKI). Previously, we reported that vanin-1, which is involved in oxidative stress, is associated with renal tubular injury. This study was aimed to determine whether urinary vanin-1 is a biomarker for the early diagnosis of AKI in two experimental models: in vivo and in vitro. In a rat model of AKI, ischemic AKI was induced in uninephrectomized rats by clamping the left renal artery for 45 min and then reperfusing the kidney. On Day 1 after renal ischemia/reperfusion (I/R), serum creatinine (SCr) in I/R rats was higher than in sham-operated rats, but this did not reach significance. Urinary N-acetyl-β-D-glucosaminidase (NAG) exhibited a significant increase but decreased on Day 2 in I/R rats. In contrast, urinary vanin-1 significantly increased on Day 1 and remained at a significant high level on Day 2 in I/R rats. Renal vanin-1 protein decreased on Days 1 and 3. In line with these findings, immunofluorescence staining demonstrated that vanin-1 was attenuated in the renal proximal tubules of I/R rats. Our in vitro results confirmed that the supernatant from HK-2 cells under hypoxia/reoxygenation included significantly higher levels of vanin-1 as well as KIM-1 and NGAL. In conclusion, our results suggest that urinary vanin-1 might be a potential novel biomarker of AKI induced by I/R.

Involvement of Vanin-1 in Ameliorating Effect of Oxidative Renal Tubular Injury in Dahl-Salt Sensitive Rats

In salt-sensitive hypertension, reactive oxygen species (ROS) play a major role in the progression of renal disease partly through the activation of the mineralocorticoid receptor (MR). We have previously demonstrated that urinary vanin-1 is an early biomarker of oxidative renal tubular injury. However, it remains unknown whether urinary vanin-1 might reflect the treatment effect. The objective of this study was to clarify the treatment effect for renal tubular damage in Dahl salt-sensitive (DS) rats. DS rats (six weeks old) were given one of the following for four weeks: high-salt diet (8% NaCl), high-salt diet plus a superoxide dismutase mimetic, tempol (3 mmol/L in drinking water), high-salt diet plus eplerenone (100 mg/kg/day), and normal-salt diet (0.3% NaCl). After four-week treatment, blood pressure was measured and kidney tissues were evaluated. ROS were assessed by measurements of malondialdehyde and by immunostaining for 4-hydroxy-2-nonenal. A high-salt intake for four weeks caused ROS and histological renal tubular damages in DS rats, both of which were suppressed by tempol and eplerenone. Proteinuria and urinary N-acetyl-β-D-glucosaminidase exhibited a significant decrease in DS rats receiving a high-salt diet plus eplerenone, but not tempol. In contrast, urinary vanin-1 significantly decreased in DS rats receiving a high-salt diet plus eplerenone as well as tempol. Consistent with these findings, immunohistochemical analysis revealed that vanin-1 was localized in the renal proximal tubules but not the glomeruli in DS rats receiving a high-salt diet, with the strength attenuated by tempol or eplerenone treatment. In conclusion, these results suggest that urinary vanin-1 is a potentially sensitive biomarker for ameliorating renal tubular damage in salt-sensitive hypertension.

Clinical and genetic analysis of 7 Chinese patients with β-ureidopropionase deficiency

β-Ureidopropionase (βUP) deficiency is an autosomal recessive disease caused by abnormal changes in the pyrimidine-degradation pathway. This study aimed to investigate the mutation of β-ureidopropionase gene (UPB1) gene and clinical features of 7 Chinese patients with βUP deficiency.We reported 7 Chinese patients with βUP deficiency who were admitted at Tianjin Children's Hospital. Urine metabolomics was detected by gas chromatography-mass spectrometry (GC-MS). Then genetic testing of UPB1 was conducted by polymerase chain reaction (PCR) method.The patients presented with developmental delay, seizures, autism, abnormal magnetic resonance imaging, and significantly elevated levels of N-carbamyl-β-alanine and N-carbamyl-β-aminoisobutyric acid in urine. Subsequent analysis of UPB1 mutation revealed 2 novel missense mutations (c.851G>T and c.853G>A), 3 previously reported mutations including 2 missense mutations (c.977G>A and c.91G>A) and 1 splice site mutation (c.917-1 G>A).The results suggested that the UPB1 mutation may contribute to βUP deficiency. The c.977G>A is the most common mutation in Chinese population.

Vanin-1 in Renal Pelvic Urine Reflects Kidney Injury in a Rat Model of Hydronephrosis

Urinary tract obstruction and the subsequent development of hydronephrosis can cause kidney injuries, which results in chronic kidney disease. Although it is important to detect kidney injuries at an early stage, new biomarkers of hydronephrosis have not been identified. In this study, we examined whether vanin-1 could be a potential biomarker for hydronephrosis. Male Sprague-Dawley rats were subjected to unilateral ureteral obstruction (UUO). On day 7 after UUO, when the histopathological renal tubular injuries became obvious, the vanin-1 level in the renal pelvic urine was significantly higher than that in voided urine from sham-operated rats. Furthermore, vanin-1 remained at the same level until day 14. There was no significant difference in the serum vanin-1 level between sham-operated rats and rats with UUO. In the kidney tissue, the mRNA and protein expressions of vanin-1 significantly decreased, whereas there was increased expression of transforming growth factor (TGF)-β1 and Snail-1, which plays a pivotal role in the pathogenesis of renal fibrosis via epithelial-to-mesenchymal transition (EMT). These results suggest that vanin-1 in the renal pelvic urine is released from the renal tubular cells of UUO rats and reflects renal tubular injuries at an early stage. Urinary vanin-1 may serve as a candidate biomarker of renal tubular injury due to hydronephrosis.

Biomarkers for Chronic Kidney Disease Associated with High Salt Intake

High salt intake has been related to the development to chronic kidney disease (CKD) as well as hypertension. In its early stages, symptoms of CKD are usually not apparent, especially those that are induced in a “silent” manner in normotensive individuals, thereby providing a need for some kind of urinary biomarker to detect injury at an early stage. Because traditional renal biomarkers such as serum creatinine are insensitive, it is difficult to detect kidney injury induced by a high-salt diet, especially in normotensive individuals. Recently, several new biomarkers for damage of renal tubular epithelia such as neutrophil gelatinase-associated lipocalin (NGAL) and kidney injury molecule-1 (Kim-1) have been identified. Previously, we found a novel renal biomarker, urinary vanin-1, in several animal models with renal tubular injury. However, there are few studies about early biomarkers of the progression to CKD associated with a high-salt diet. This review presents some new insights about these novel biomarkers for CKD in normotensives and hypertensives under a high salt intake. Interestingly, our recent reports using spontaneously hypertensive rats (SHR) and normotensive Wistar Kyoto rats (WKY) fed a high-salt diet revealed that urinary vanin-1 and NGAL are earlier biomarkers of renal tubular damage in SHR and WKY, whereas urinary Kim-1 is only useful as a biomarker of salt-induced renal injury in SHR. Clinical studies will be needed to clarify these findings.

A study on the effect of the internal exposure to (210)Po on the excretion of urinary proteins in rats

This study was designed to assess the feasibility of a noninvasive urine specimen for the detection of proteins as indicators of internal exposure to ionizing radiation. Three groups of rats (five in each group) were intravenously injected with 1601 ± 376, 10,846 ± 591 and 48,467 ± 2812 Bq of (210)Po in citrate form. A sham-exposed control group of five rats was intravenously injected with sterile physiological saline. Daily urine samples were collected over 4 days following injection. Purification and pre-concentration of urinary proteins were carried out by ultrafiltration using a 3000 Da molecular weight cutoff membrane filter. The concentration of common urinary proteins, namely albumin, alpha-1-acid glycoprotein, immunoglobulins IgA and IgG, was measured by an enzyme-linked immunosorbent assay. Urinary excretion of albumin decreased dose-dependently (p < 0.05) 96 h post-injection relative to the control group. In contrast, no statistically significant effects were observed for other proteins tested. The dose-dependent decrease in urinary excretion of albumin observed in this study underscores the need for further research, which may lead to the discovery of new biomarkers that would reflect the changes in the primary target organs for deposition of (210)Po.

Five cases of beta-ureidopropionase deficiency detected by GC/MS analysis of urine metabolome

The clinical presentation of inborn errors of pyrimidine degradation varies considerably from asymptomatic to severe neurological illness. We have reported a method to screen for and make a chemical diagnosis of beta-ureidopropionase deficiency, leading to the discovery of the first asymptomatic case of this disease. In this method, the recovery of beta-ureidopropionate and beta-ureidoisobutyrate, the key biomarkers, was very high,and the adoption of GC/MS and targeted analysis enabled us to simultaneously obtain information related and unrelated to pyrimidine metabolism. The present study reports the results of a large-scale screening of 24,000 newborns using dried urine on filter paper. Identification of a total of four asymptomatic patients among newborns suggests the high incidence (1/6000) of this disease in Japan. While these newborns were asymptomatic, two additional cases detected at the age of 5 years as well as 3 months with this method for high-risk screening had autism and West syndrome, respectively.The key biomarkers and alpha-ureidobutyrate used as an internal standard were found to give not only their di-trimethylsilyl derivatives but also tri-trimethylsilyl derivatives, upon derivatization. The mass spectra and retention times of their tri-trimethylsilyl derivatives and data handling for quantification of the markers are presented.Identification of individuals with defects in pyrimidine metabolism would realize personalized medication in cancer chemotherapy with pyrimidine analogs such as 5-fluorouracil.

On human tissue kallikrein activity in urine of Brazilian White and Black primary hypertensive patients

OBJECTIVE

To evaluate the possible relationship between the human tissue kallikrein amidase activity with sex and ethnicity in Brazilian primary hypertensive patients.

DESIGN

Population-based study.

PARTICIPANTS

One hundred men and women, Black and White primary hypertensive patients aged 20 years and older were selected. Eighty nine healthy individuals, paired according to age, sex, and ethnics were used as controls.

METHODS

Early-morning midstream urine was used. Human tissue kallikrein amidase activity was estimated with D-Val-Leu-Arg 4-nitroanilide substrate. Creatinine was determined by a method based on Jaffe's reaction. hK1 amidase activity is expressed in microM/(min x mg creatinine) to correct for differences in urine flow rate. Data are expressed as medians.

RESULTS

Human tissue kallikrein amidase activity was significantly lower in the urine of hypertensive patients (0.210 microM/(min x mg creatinine) than in the urine of control subjects (0.260 microM/(min x mg creatinine) (P = .010). This result supports data from the literature. Contrasting to what was already reported, namely that human tissue kallikrein excretion is higher in females than in males, and especially higher in Caucasians than in African Americans, our results show that, in the urine of Brazilian hypertensive patients and control subjects, no significant effect of sex and ethnicity on human tissue kallikrein amidase activity was observed.

CONCLUSIONS

The lack of ethnicity effect supports what was already asserted, namely, that, in Brazil, at an individual level, color, as determined by physical evaluation, is a poor predictor of genomic African ancestry, estimated by molecular markers.

Possible indirect detection of rHuEPO administration in human urine by high-performance liquid chromatography tandem mass spectrometry

The present study is based on the assumption that changes in an ADMA-DDAH-NOS (ADMA-asymmetrical dimethylarginine; DDAH-dimethyl-arginine dimethylaminohydrolase; NOS-nitric oxide synthase) system could be employed as indirect markers for recombinant human erythropoietin (rHuEPO) administration in doping control. We assessed a predictive value of four proposed new markers for rHuEPO abuse. Preliminary data showed that concentrations of ADMA, symmetrical dimethylarginine (SDMA), citrulline and arginine in human urine were increased after administration of a single intravenous erythropoietin injection (2000 U day(-1), Epocrine, St-Petersburg, Russia). The study of variations of ADMA, SDMA, arginine and citrulline levels before and after rHuEPO administration was performed with two healthy male volunteers. Urine samples were collected before rHuEPO administration and urinary concentrations of ADMA and SDMA were determined at 10.0-40 microg mL(-1) and of arginine and citrulline at 0.5-10 microg mL(-1). A single dose injection of rHuEPO caused an increase in ADMA, SDMA, arginine and citrulline concentrations up to 40-270 microg mL(-1), 40-240 microg mL(-1), 10-60 microg mL(-1) and 12-140 microg mL(-1), respectively. These preliminary results indicated that an indirect approach could be used as a pre-screening of urine samples in order to decrease the number of samples with a low probability of rHuEPO abuse and, thus, save costs and human workload.

The Amidase Activity of Human Tissue Kallikrein Is Significantly Lower in the Urine of Patients With Systolic Heart Failure

BACKGROUND

Heart failure (HF) is a clinical syndrome that activates several neurohumoral systems. There is little information on the participation of renal kallikrein-kinin system (KKS) in HF. Kallikreins are key enzymes in this system. Thus it was decided to evaluate the role of renal human tissue kallikrein (hK1) in HF patients and, indirectly, to evaluate the role of renal KKS in this disease.

METHODS AND RESULTS

Twenty-eight systolic HF patients, > or =18 years, in New York Heart Association's functional classes II-IV, with left ventricular ejection fraction (LVEF) < or =40%, not receiving angiotensin-converting enzyme inhibitors were selected. Twenty-eight healthy individuals, paired according to gender, ethnics and age, were used as controls. Early-morning midstream urine from every subject was used. hK1 amidase activity was estimated with D-Val-Leu-Arg-Nan substrate. Creatinine was determined by Jaffe's method. hK1 amidase activity was expressed in muM.min(-1).mL(-1) urine and in muM.min(-1).mg(-1) creatinine to correct for differences in urine flow rate. hK1 amidase activities were significantly lower in the urine of HF patients.

CONCLUSION

Because the hK1 amidase activity is significantly lower in the urine of systolic HF patients, it can be supposed that the activity of renal KKS may be suppressed in this disease.

A clinical study of Yigu capsule in treating postmenopausal osteoporosis

OBJECTIVE

To observe the efficacy and safety of Yigu capsule (YGC), a Chinese herbal compound preparation, in treating postmenopausal osteoporosis (PMO) and to explore its possible mechanism.

METHODS

The clinical study was conducted in a prospective, randomized, double blinded method lasting for 6 months with placebo and positive control. Two hundred and ten PMO patients with confirmed diagnosis were assigned into the YGC group, the calciferol group and the placebo group. Besides being administered element calcium, they were treated with YGC, calciferol capsule and placebo capsule respectively. And such symptoms as newly found fracture and ostealgia, bone mineral density (BMD) of the 2nd-4th lumbar vertebrae (L(2-4)) and upper femur, blood and urinary indexes for bone metabolism, sex hormone level and adverse reaction that occurred in patients were observed.

RESULTS

In the YGC group, the total effective rate was 95.50%, with no new occurrence of fractures, which was significantly better than that in the other two groups (P < 0.05). Moreover, in the YGC group, the increase rate of BMD was 9.83% in L(2-4), 4.09% in femoral neck, 4.60% in Wards triangle, 3.00% in greater trochanter, which was also better than that in the placebo group (P < 0.05, P < 0.01). As compared with the placebo group, levels in the YGC group of urinary oxyproline hydroxyproline/creatinine, urinary calcium/creatinine were significantly lower, serum and bone alkaline phosphatase, osteocalcin, estradiol and estradiol/testosterone were significantly higher, but no difference was shown in the comparison of testosterone level. In the observation period, no abnormality in blood or urine routine, liver or renal function was found. Only mild, transient gastro-intestinal response occurred in individual patients, but it did not affect the treatment.

CONCLUSION

YGC could treat PMO effectively, as it could obviously increase the BMD of lumbar vertebrae and coxafemoral bone, elevate the alleviating rate of ostealgia and incessant motion time, yet causing no newly found compressive fracture of vertebrae, or and any related adverse reaction. YGC could not only promote the formation, but also inhibit the absorption of bone as well as increase the sex hormone level. Therefore, it is a pure Chinese herbal compound preparation worthy of further research and development.

Biological monitoring of workers exposed to N , N -dimethylformamide in synthetic leather manufacturing factories in Korea

OBJECTIVES

To investigate the relationship between N, N-dimethylformamide (DMF) exposure and excretion of urinary N-acetyl- S-( N-methylcarbamoyl)cysteine (AMCC) and N-methylformamide (NMF) in workers at synthetic leather manufacturing factories in Korea, for the first time.

METHODS

One-hundred forty-four male workers at nine synthetic leather manufacturing factories were surveyed. Exposure to DMF was evaluated through breathing zone air sampling followed by analysis via a gas chromatograph equipped with a flame ionization detector (GC-FID). The levels of NMF and AMCC were determined by a GC with a flame thermionic detector (GC-FTD). Urine samples were collected at the end of the workshift.

RESULTS AND CONCLUSIONS

Geometric mean of workplace air DMF and urinary NMF was 8.8 ppm and 47.5 mg/l, respectively, and the level of DMF and NMF was significantly correlated. The biological exposure limit for NMF (15 mg/ml) was exceeded in 89.5% of urine samples, and 37.9% of air samples exceeded the environmental DMF exposure limit (10 ppm), indicating a serious health risk to the employees of the synthetic leather industry in Korea. Exposure to 10 ppm DMF in the workplace air corresponded to a urinary NMF concentration of 53.4 mg/l. Alcohol intake the day before urine was sampled influenced NMF excretion into urine (40.5 mg/l NMF for the no-alcohol group and 94.6 mg/l for the group consuming more than 63.0 g alcohol/day). We could not find a significant relationship between air DMF and urinary AMCC concentration. Exposure to 10 ppm DMF corresponded to an AMCC concentration of 8.0 mg/l in the urine samples collected on the same day as the air was sampled.

Rapid gas chromatographic-mass spectrometric diagnosis of dihydropyrimidine dehydrogenase deficiency and dihydropyrimidinase deficiency

A rapid yet reliable chemical diagnosis for dihydropyrimidine dehydrogenase (DHPD) deficiency, and possibly dihydropyrimidinase (DHP) deficiency in cancer patients, prior to therapy with pyrimidine analogues such as 5-fluorouracil, is desired for prevention of severe side-effects by these drugs. We have reported the basic separation and quantitation technology for pyrimidine metabolites using gas chromatography-mass spectrometry. A proposal to use the number (n) of standard deviations (SD) above the normal mean, as the index of the excessive urinary excretion of the metabolites appears not to be commonly used. When used, the values were too small, such as two or three, even in genetic disorders. Here, we applied the method to 11 urine specimens from proven cases including two DHP carriers and proved how specific the method is, because "n"-values were markedly large for thymine (T), uracil (U) and/or dihydrothymine (DHT) and dihydrouracil (DHU). In three cases with DHPD deficiency, two were siblings, one with symptoms and the other without, n was 12 for T and 5.9 for U, and 5-hydroxymethyluracil was distinctly detected. These values indicate that the nature of genetic mutation relates closely to the degree of metabolite accumulation in pyrimidine disorders. In six patients with DHP deficiency, n was 8.4-12 for DHT and 7.2-11 for DHU. Many mutations are known for both genes and the assay of residual enzyme activity may be time-consuming or invasive especially for those with DHP deficiency. Thus, this noninvasive yet comprehensive urinalysis has great value for those without a family history, as the first trial, before DNA or the enzyme assay. Our findings again raise the question whether the metabolic block really causes the symptoms found in pyrimidine disorders.

Urinary biotinidase and alanine excretion in patients with insulin-dependent diabetes mellitus

Twenty-four-hour urine specimens from 21 juvenile insulin-dependent diabetics and 10 healthy controls were compared with respect to biotinidase activity and alanine content. Urinary biotinidase activity was analysed by a newly developed high-performance liquid chromatography (HPLC) method. It was found that the excretion of biotinidase in urine was elevated in diabetics (7.02 mU/d; p < 0.005) as compared with controls (not detectable). Alanine excretion was also found to increase (p < 0.01) in diabetics. Biotinidase excretion in diabetics was correlated with alanine excretion (rS = 0.667; p < 0.01), but not with protein, albumin or N-acetyl-beta-glucosaminidase excretion. The simultaneous elevation of urinary biotinidase and alanine excretion in juvenile diabetics suggests that changes in kidney metabolism arise in the early stages of diabetes.

Amidase activity of human Bence Jones proteins

Bence Jones proteins purified from urine of patients with multiple myeloma were found to be capable of hydrolyzing carbobenzoxy-L-valyl-glycyl-L-arginine p-nitroanilide (Chromozym TRY) and benzoyl-L-arginine p-nitroanilide (BApNA), synthetic chromogenic substrates for trypsin. The amidolytic activity obeyed classic Michaelis-Menten kinetics, exhibiting optimal activity around pH 8.4 and apparent Km of 140-730 microM and 18-27 microM for Chromozym TRY and BApNA, respectively. No activity was detected with intact IgG or Fab fragment, whereas the activity comparable to those of Bence Jones proteins was found with light chain derived from inactive IgG. Several lines of circumstantial evidence indicate that the observed activity was not due to contaminating enzyme.

Aspartylglucosaminuria in a Puerto Rican family: additional features of a panethnic disorder

We report on 3 Puerto Rican brothers with the clinical and laboratory findings of aspartylglucosaminuria (AGU). Their parents were first cousins. The affected sibs have the "cardinal" manifestations of AGU, including developmental disabilities, progressive "coarsening" of the face, and early onset of hepatosplenomegaly. Biochemical studies showed elevated levels of urinary aspartylglucosamine and very low activity of aspartylglucosaminidase(AGA) in cultured fibroblasts. With long term follow-up, previously undescribed manifestations were noted, including radiographic evidence of spondylolysis and spondylolisthesis in early childhood and development of macro-orchidism during puberty. This family shows that AGU is not limited to individuals of Finnish background, but that the gene is panethnic in distribution and that additional changes, not previously noted, may present with advancing age.

Effect of amiloride on urinary and renal kallikrein in the rat

A single intraperitoneal injection of amiloride in the range of 2.7, 5.4, 10.9, and 21 mumol/100 g body wt in female adult rats produced, in the two successive periods of 4 h following its administration, a significant decrease in the urinary excretory rate of kallikrein. Amiloride, 10.9 mumol/100 g body wt, which significantly reduced active kallikrein, also decreased, but less significantly, the trypsin-activated kallikrein in the urine. The fall in the excretory rate of kallikrein cannot be explained by its enzymatic inhibition by amiloride, since the inhibition was only present at higher concentrations. In hyperhydrated rats amiloride did not change the kallikrein excretory rate in the urine collected within 4 h after the injection. Rats simultaneously injected with 7.6 mumol/100 g body wt furosemide and 10.9 mumol/100 g body wt amiloride excreted levels of kallikrein similar to those found in rats injected with furosemide alone. The kidneys of rats removed after 4 h of administration of 10.9 mumol/100 g body wt amiloride showed a significant lowering of the kallikrein activity compared with the respective controls. The decrease of renal kallikrein tended to be similarly pronounced in those rats that received amiloride and furosemide simultaneously. These results confirm the depressive effect of amiloride on kallikrein excretion, which may be explained by an inhibitory action on kallikrein release, activation, and synthesis by the renal cells.

Degradation of beta 2-microglobulin in infected urine by leukocyte elastase-like activity

Loss of beta 2-microglobulin in human urine at near neutral pH is described. beta 2-Microglobulin was found to be unstable at pH 7.4 in 15 out of 70 specimens with bacterial infection. Breakdown of this protein was shown to be most active between pH 6.5 and 8.0 but some proteolysis also occurred between pH 5.0 and 6.0. Evidence that proteolysis of beta 2-microglobulin near neutral pH is due to neutrophil elastase-like activity was obtained by the following methods: use of the model elastase substrate L-pyroglutamyl-L-prolyl-L-valine-p-nitroanilide and the specific inhibitor 2-trifluoroacetylaminobenzenesulphonyl fluoride; use of neutrophil granule extracts and determination of the size distribution of beta 2-microglobulin proteolytic fragments. If increased numbers of pus cells are present, it is suggested that screening for elastase-like proteolysis should be undertaken before interpreting a measurement of beta 2-microglobulin.

Finger clubbing and aspartylglucosamine excretion in a laxative-abusing patient

A young woman with a previous history of anorexia nervosa presented with severe finger clubbing. Urine samples intermittently contained significant amounts of aspartylglucosamine. Liver biopsy showed abnormal cytoplasmic inclusions in phagocytic cells. The patient was found to be abusing senna laxative.

Variation of urinary excretion of aspartylglucosamine and associated clinical findings in aspartyglucosaminuria

The urinary excretion of aspartylglucosamine (AADG), the main accumulating glycoprotein degradation product in aspartylglucosaminuria (AGU), was studied in 40 patients at various stages of the disease. Only slight variation was found when the amount of AADG excreted by ten AGU patients under 10 years of age was compared with AADG excretion of older patients at a clinically advanced stage of the disease. The 24h AADG excretion of the younger patients was 354 mg compared with 441 mg in the group of ten patients over 20 years of age. Clinical symptoms were unrelated to AADG excretion.

Aspartylglucosaminuria: unique biochemical and ultrastructural characteristics

The observation of vacuolated lymphocytes in a coarsely featured two year old female with hepatosplenomegaly, mitral insufficiency, and mild psychomotor retardation led to the first diagnosed case of aspartylglucosaminuria in the United States. Although physical characteristics and bone roentgenograms were consistent with a mucopolysaccharide disorder, analysis of the urine showed no mucopolysaccharide elevation. The chromatographic, enzymatic, and ultrastructural studies confirming the diagnosis are presented.