[Clinical characteristics and related factors analysis of adrenal crisis occurred in children with primary nephrotic syndrome]

Objective: To investigate the clinical characteristics and related factors of corticosteroid induced adrenal crisis (AC) in children with primary nephrotic syndrome (NS). Methods: Case control study. The case group included 7 children aged 1 to 18 years with NS combined with AC hospitalized in Peking University First Hospital from January 2016 to May 2021 (AC group). According to the ratio of case group: control group 1: 4, 28 children aged 1 to 18 years who were diagnosed with NS without AC during the same period were matched as controls (non-AC group). Clinical data were collected. The clinical characteristics of AC were described. The clinical parameters were compared between the 2 groups by t test, Mann-Whitney U test or Fisher's test. Receiver operating characteristic (ROC) curve was used to analyze the cutoff values of clinical parameters for prediction of AC. Results: The AC group included 4 boys and 3 girls aged 6.9 (4.6, 10.8) years. The non-AC group included 20 boys and 8 girls aged 5.2 (3.3, 8.4) years. All AC events occurred during the relapse of NS with infection. Seven children had gastrointestinal symptoms such as nausea, vomiting and abdominal pain. Six children had poor mental state or impaired consciousness. No significant differences in NS course, corticosteroid treatment course, corticosteroid type, steroid dosage, steroid medication interval, the proportion of gastroenteritis and fever existed between the two groups (all P>0.05). Compared with the non-AC group, the duration from the onset of the relapse of NS until hospitalization in the AC group was significantly shorter (0.2 (0.1, 0.6) vs. 1.0 (0.4, 5.0) month,U=25.50, P=0.005). The 24 h urinary total protein (UTP) level was significantly higher in the AC group (193 (135, 429) vs. 81 (17, 200) mg/kg, U=27.00,P=0.036) than the non-AC group. The serum albumin level in the AC group was significantly lower((13.1±2.1) vs. (24.5±8.7) g/L,t=-6.22,P<0.001) than the non-AC group. There were significantly higher total white blood cell counts ((26±9)×109 vs. (11±5)×109/L,t=4.26,P=0.004), percentage of neutrophils (0.71±0.08 vs. 0.60±0.19,t=2.56,P=0.017) and the proportion of children with C reactive protein level≥8 mg/L (3/7 vs. 0,P=0.005) in the AC group than in the non-AC group. ROC curve analysis showed that the cutoff value of 24 h UTP was 122 mg/(kg·d) with a sensitivity of 100.0% and specificity of 70.4%. The cutoff value of serum albumin was 17.0 g/L with a sensitivity of 100.0% and specificity of 82.1%. Conclusions: Gastrointestinal symptoms and poor mental state were prominent manifestations of AC in children with NS. High 24 h UTP level, low serum albumin level, high peripheral white blood cell counts, high neutrophils percentage, and high C-reactive protein level during the early stage of NS relapse may be related to the occurrence of AC in children with NS.

[Suitability of estimated urine protein using different estimated 24 h urine creatinine equations in children with glomerular diseases]

Objective: To assess the reliability of estimated urine protein to predict 24 h urine protein excretion in children with glomerular diseases. Methods: Four hundred and forty-three children with glomerular diseases, who were admitted to pediatric department of Peking University First Hospital from January 2001 to December 2021, were enrolled in the cross-sectional study. The 24 h estimated urine creatinine which calculated by 6 previously described equations, 24 h measured urine creatinine, measured urine protein-to-creatinine ratio(UPCR), 24 h urine protein (24 hUP) and urinary sediment analysis with microscopy were collected, estimated urine protein was computed as the product of measured UPCR and estimated or measured 24 h urine creatinine. Spearman correlation analysis, Bland-Altman analysis and linear regression analysis were used to compare the correlation, agreement and accuracy between estimated urine protein and 24 hUP, and the effect of urinary protein level and erythrocyte numbers on their relationship was analyzed. Results: Of 443 children with glomerular diseases (aged (11±4) years, 221 male, 222 female), there were 216 participants with nephrotic syndrome, 78 participants with IgA nephropathy, 47 participants with Alport syndrome, 42 participants with lupus nephritis, 58 participants with purpura nephropathy, and 2 participants with isolated proteinuria. Spearman correlation analysis showed a strong correlation between estimated urine protein and 24 hUP (r=0.90, P<0.05), and the correlation improved after multiplying the measured UPCR by 24 h measured urine creatinine (r=0.94, P<0.05). Improved correlation was also observed using the estimated urine creatinine which calculated by Hellerstein formula, Ghazali-Barratt formula, Ellam formula, Walser formula, Cockcroft-Gault formula, Ix formula (r=0.93, 0.94, 0.90, 0.90, 0.94, 0.93, all P<0.05).Bland-altman analysis showed that the difference between measured UPCR and 24 hUP was (-0.30±2.22) g, consistency limit was -4.65-4.04, and the consistency improved after 24 h measured urine creatinine correction (difference was (0.27±1.31) g, consistency limit -2.30-2.84). The consistency of estimated urine protein was further improved after correction by different formulas, and the Cockcroft-Gault formula showed the best consistency between estimated urine protein and 24 hUP (difference was (0.11±1.18)g, consistency limit was -2.20-2.42). Linear regression analysis showed that measured UPCR had poor accuracy in predicting 24 hUP (R²=0.55, α=0.48, β=0.60, P<0.05), and the accuracy improved after 24 h measured urine creatinine correction, the accuracy of estimated urine protein for predicting 24 hUP was further improved by using different formulas, and Cockcroft-Gault formula was the best (R²=0.81, α=0.18, β=0.96, P<0.05). With the increase of urinary protein level and the decrease of urinary erythrocyte numbers, the correlation, agreement and accuracy between estimated urine protein and measured UPCR and 24 hUP were improved(all P<0.05). Except Ellam and Ix formulas, estimated urine protein using the rest four formulas outperformed measured UPCR(all P<0.05). Conclusion: The 24 h urine creatinine excretion rate (obtained by the Cockcroft-Gault equation)-weighted urine protein-to-creatinine ratio more reliably predicts 24 hUP than measured UPCR alone in children with glomerular diseases.

[C1q or IgA deposition in glomeruli of children with primary membranous nephropathy]

Objective: To assess the correlation of glomerular C1q or IgA deposition with clinical and pathological features of primary membranous nephropathy (PMN) in children. Methods: The clinical and pathological manifestations including (phospholipase A2 receptor, PLA2R) and IgG subclasses staining in renal biopsies, serum anti-PLA2R antibody and therapeutic response of 33 children diagnosed with PMN in Peking University First Hospital from December 2012 to December 2020 were retrospectively summarized and analyzed. According to results of PLA2R test and findings renal pathological, the patients were divided into PLA2R-related group and non-PLA2R-related group, typical MN group and atypical MN group, C1q deposit group and non-C1q deposit group, as well as IgA deposit group and non-IgA deposit group respectively. T-test, Mann-Whitney U test and Fisher's exact probability test were used for comparison between the groups. Results: Among the 33 children with PMN, there were 20 males and 13 females, of that the age of onset was 11 (8, 13) years, and 32 patients had nephrotic level proteinuria. Renal biopsies were performed at 4.6 (2.1, 11.6) months after onset, and 28 patients (85%) received glucocorticoid or immunosuppressive therapy prior to renal biopsy. There were 20 cases (61%) with PLA2R-related MN and 13 cases (39%) with non-PLA2R-related MN. Compared with the non-PLA2R-related group, the PLA2R-related group had an older age of onset (12 (10, 13) vs. 7 (3, 12) years, Z=-2.52, P=0.011), a lower preceding infection rate (45% (9/20) vs. 11/13, P=0.032) and lower spontaneous remission rate (0 vs. 4/13, P=0.017). Renal PLA2R positivity was significantly associated with predominant or co-deposition of IgG4 (13/17 vs. 5/15, P=0.031) and low albumin levels at renal biopsy ((25±6) vs. (29±7) g/L, t=2.14, P=0.041). There were 12 patients with typical PMN and 21 patients with atypical PMN, and no significant difference in clinical and pathological manifestations was found between these 2 groups (all P>0.05). There were 10 cases (32.3%) with glomerular C1q deposition, and their disease course before renal biopsy was significantly shorter than those without C1q deposition (1.8 (0.8, 5.9) vs. 6.0 (2.5, 22.3) months, Z=-2.27, P=0.023). Twelve cases (36.4%) had glomerular IgA deposition, and their course of disease,clinical and pathological manifestations were not significantly different from those without IgA deposition (all P>0.05). Conclusion: Glomerular C1q or IgA deposition may not affect the clinical manifestations, glomerular PLA2R and IgG subclasses staining pattern, or the response to treatment of PMN in children.

[Investigation and analysis of noise hazards in three key industries in Shenzhen City]

Objective: To understand the basic situation of noise hazards in wood furniture manufacturing, stone processing and special equipment manufacturing industries in Shenzhen City, and to provide basis for preventing and controlling noise hazards. Methods: In August 2019, stratified random sampling ws used to select 21 wood funiture manafacturing, 15 stone processing and 24 special equipment manufactruing as survey object. Through the methods of occupational health field investigation, noise intensity measurement and occupational health examination data collection, the noise hazards of 60 enterprises in three industries were statistically analyzed. Results: There were 154, 44 and 113 noise detection points in wood furniture manufacturing, stone processing and special equipment manufacturing enterprises, and 101, 27 and 78 out of standard points respectively, and the exceeding standard rates were 65.6% (101/154) , 61.4% (27/44) and 69.0% (78/113) , respectively. There were 1670, 172 and 856 workers exposed to noise in the three industries. Among them, 1198, 134 and 703 people had taken occupational health examination. The physical examination rates were 71.7% (1198/1670) , 77.9% (134/172) and 82.1% (703/856) , respectively. The abnormal rates were 19.1% (229/1198) , 51.5% (69/134) and 37.8% (266/703) , respectively. Conclusion: High intensity noise working environment, too long noise exposure time, incorrect wearing of personal protective equipment and neglect of occupational health examination are important reasons for hearing loss of noise exposed personnel.

[Analysis on diagnosis rate of chronic kidney disease in hospitalized pediatric patients]

Objective: To analyze diagnosis rate of chronic kidney disease (CKD) in hospitalized pediatric patients in a single center and understand pediatricians' awareness of CKD. Methods: This was a cross-sectional study. Children who were admitted to the Division of Pediatric Nephrology, Peking University First Hospital from January 1, 2008 to December 31, 2017 and met the diagnostic criteria of CKD (kidney disease: improving global outcomes 2012 guideline) were recruited. A total of 4 472 cases were enrolled. Original CKD diagnosis was collected from the home page of medical records. Actual CKD diagnosis was validated and corrected by reviewing medical records and recalculating glomerular filtration rate. The diagnosis rate and influencing factors of pediatric CKD, the distribution and etiology of actual CKD were analyzed. The comparison between groups were performed with χ(2) test. Results: In 4 472 cases, there were 3 470 cases in actual CKD stage 1, among which only 24 cases were in original CKD stage 1. There were 543 cases in actual CKD stage 2-3, among which only 181 cases were in original CKD stage 2-3. Three hundred and one cases were in actual CKD stage 4-5, including 290 cases in original CKD stage 4-5. In addition, there were 43 cases with unknown CKD stage and 115 cases with acute kidney injury. Compared to original CKD diagnosis, the diagnosis rates of CKD stage 1-5 were 0.7% (24/3 470), 16.7% (58/348), 63.1% (123/195), 90.7% (78/86) and 98.6% (212/215), respectively. The proportions of actual CKD stage 1-5 were 80.4% (3 470/4 314), 8.1% (348/4 314), 4.5% (195/4 314), 2.0% (86/4 314) and 5.0% (215/4 314). The etiology of actual CKD included primary glomerular disease (62.2%, 2 686/4 314), secondary glomerular disease (19.7%, 849/4 314), hereditary kidney disease (9.1%, 391/4 314), congenital abnormalities of the kidney and urinary tract (CAKUT) (3.1%, 135/4 314), tubulointerstitial disease (2.2%, 94/4 314) and etiology uncertain (2.1%, 89/4 314). The leading cause of end stage renal disease was etiology uncertain (31.1%, 67/215), followed by hereditary kidney disease (24.2%, 52/215), CAKUT (16.3%, 35/215) and primary glomerular disease (16.3%, 35/215). Conclusions: Among actual CKD hospitalized pediatric patients, the diagnosis rate of CKD given by physicians at discharge was relatively low, especially patients in earlier CKD stages, which reflected serious lack of physicians' awareness of CKD.

[A multicenter study of reference intervals for 15 laboratory parameters in Chinese children]

Objective: To establish comprehensive laboratory reference intervals for Chinese children. Methods: This was a cross-sectional multicenter study. From June 2013 to December 2014, eligible healthy children aged from 6-month to 17-year were enrolled from 20 medical centers with informed consent. They were assessed by physical examination, questionnaire survey and abdominal ultrasound for eligibility. Fasting blood samples were collected and delivered to central laboratory. Measurements of 15 clinical laboratory parameters were performed, including estradiol (E2), testosterone(T), luteinizing hormone(LH), follicle-stimulating hormone(FSH), alanine transaminase(ALT), serum creatinine(Scr), cystatin C, immunoglobulin A(IgA), immunoglobulin G(IgG), immunoglobulin M(IgM), complement (C3, C4), alkaline phosphatase(ALP), uric acid(UA) and creatine kinase(CK). Reference intervals were established according to central 95% confidence intervals for reference population, stratified by age and sex. Results: In total, 2 259 children were enrolled. Finally, 1 648 children were eligible for this study, including 830 boys and 818 girls, at a mean age of 7.4 years. Age- and sex- specific reference intervals have been established for the parameters. Reference intervals of sex hormones increased gradually with age. Concentrations of ALT, cystatin C, ALP and CK were higher in children under 2 years old. Serum levels of sex hormones, creatinine, immunoglobin, CK, ALP and urea increased rapidly in adolescence, with significant sex difference. In addition, reference intervals were variable depending on assay methods. Concentrations of ALT detected by reagents with pyridoxal 5'-phosphate(PLP) were higher than those detected by reagents without PLP. Compared with enzymatic method, Jaffe assay always got higher results of serum creatinine, especially in children younger than 9 years old. Conclusion: This study established age- and sex- specific reference intervals, for 15 clinical laboratory parameters based on defined healthy children.

[Evaluation of transperineal sonography for lower urinary tract symptoms after pelvic floor reconstruction]

Objective: To evaluate transperineal sonography for lower urinary tract symptoms after pelvic floor reconstruction. Methods: Eighty-three patients with severe pelvic organ prolapse received surgeries in Fuzhou General Hospital from September 2014 to September 2015, dividing into two groups: 27 patients were selected to receive transvaginal mesh (TVM) pelvic floor reconstruction surgery with tension-free vaginal tape-Abbrevo (TVT-Abbrevo) incontinence surgery, named TVM+TVT-Abbrevo group; 56 patients were selected to receive TVM pelvic floor reconstruction surgery only, named TVM group. The ultrasonic parameters at rest, on contraction and Valsalva condition respectively were observed and measured, including the bladder neck descent (BND), urethral rotation angle, retrovesical angle, levator urethra gap (LUG), the existence of bladder neck funneling, position of the tape, by using 2D and 3D transperineal ultrasound. Results: The two groups were compared with the ultrasonic parameters before and after operation: two groups of patients with postoperative BND [(2.3±0.5) versus (3.1±0.7) cm, (1.6±0.4) versus (3.6±0.4) cm] were significantly reduced, the difference was statistically significant (P=0.02, P<0.01). The two groups of LUG before and after operation [(3.62±0.45) versus (3.26±0.92) cm, (2.96±0.47) versus (2.72±0.38) cm] both had significant difference by maximum Valsalva (P<0.01, P=0.04). There was statistical significance difference of urethral rotation angle in TVM+TVT-Abbrevo group by maximum Valsalva (P=0.01). Observation of morphology: (1) 2 patients with difficulty in urination in TVM+TVT-Abbrevo group, ultrasound showed when the position of the bladder down the urethra discount; 4 patients with stress urinary incontinence (SUI), ultrasound showed slings off or release. (2) One patient with difficulty in urination in TVM group, but ultrasound showed lower urinary tract anatomy were normal; 5 patients with SUI, ultrasound showed the position of the bladder neck were significantly lower in 3 patients, showing high mobility, and the other 2 patients had a larger urethral diameter, showing a tendency of natural deletion. Conclusion: s Anatomy of lower urinary tract could be clearly showed by transperineal sonography. This could provide imaging support for the diagnosis of lower urinary tract symptoms after pelvic floor reconstruction.

Effect of Portulaca oleracea extracts on growth performance and microbial populations in ceca of broilers

The aim of this study was to investigate the effects of Portulaca oleracea extracts on growth performance and microbial populations in the ceca of broilers. A total of 120 one-day-old broilers were randomly divided into 3 groups. Portulaca oleracea extracts were added to diets at 0.2 and 0.4% (wt/wt; POL-0.2, POL-0.4), respectively. The control (CON) group was administered with no P. oleracea extract supplementation. Body weight gain and feed conversion ratio were recorded every 2 wk. On d 28 and 42, the cecal contents were collected and assayed for Escherichia coli, Lactobacillus, and Bifidobacterium populations. Additionally, the pH of the ileum and cecum was measured. The results showed that both on d 28 and 42 BW gain of P. oleracea extract supplementation groups was significantly higher, whereas the feed conversion ratio was lower (P < 0.05) compared with CON. On d 28 and 42, significantly (P < 0.05) fewer E. coli were recovered from ceca of broilers provided with the POL-0.2 diet than from broilers provided with the control diet. The quantities of Lactobacillus and Bifidobacterium of POL-0.2 were significantly (P < 0.05) higher than CON. Results showed P. oleracea extracts have no distinct influence on intestinal pH. These data suggest that P. oleracea extract supplementation significantly altered the cecal bacterial community without affecting the intestinal pH.

Survey on tetracycline resistance and antibiotic-resistant genotype of avian Escherichia coli in North China

The experiment was performed to investigate the tetracycline resistance and antibiotic-resistant genotype of avian Escherichia coli in North China and to analyze the correlation of genotype and phenotype. The resistance of 164 E. coli isolates (from Beijing, Tianjin, inner Mongolia, Shanxi, and Hebei regions of China) to tetracycline, doxycycline, and minocycline was investigated by using a drug susceptibility test. The results show that the rate of resistance to tetracycline antibiotics was 89.63% (147/164). The higher resistance rate was 84.76% (139/164) to tetracycline and 70.12% (115/164) to doxycycline, and the lowest resistance rate was 4.88% (8/164) to minocycline. The distribution of tetracycline resistance (Tcr) genes (tetA, tetB, tetC, and tetM) in avian E. coli isolates was detected by PCR. Of the isolates, 82.32% (135/164) carried tetracycline resistance genes. The positive rates of tetA, tetB, and tetM were 57.93% (95/164), 38.41% (63/164), and 10.97% (18/164), respectively. No tetC was amplified in avian E. coli isolates. The total positive rate of resistance genes (82.32%) was almost equal to the total rate of resistance to tetracycline antibiotics (89.63%). Thus, the positive rate of genotype was basically in line with that of phenotype for tetracycline resistance. The tetracycline resistance genes are widely distributed in E. coli and their main resistance mechanism to tetracycline is the active efflux effect mediated by tetA and tetB.

Molecular epidemiological survey on aminoglycoside antibiotics-resistant genotype and phenotype of avian Escherichia coli in North China

Monitoring drug resistance in Escherichia coli is important for prevention and treatment of colibacillosis. To choose effective drugs to prevent and control avian colibacillosis in North China, we investigated resistance of 205 E. coli isolates (from Beijing, Tianjin, inner Mongolia, Shanxi, and Hebei regions) to commonly used clinical aminoglycoside antibiotics using a drug susceptibility test. The results show that the isolates had varying degrees of resistance to kanamycin, gentamicin, streptomycin, amikacin, neomycin, and spectinomycin. Particularly, the resistance rates of the former 3 antibiotics exceeded 40%. To explore the reasons for wide drug resistance, aminoglycosides modifying enzymes (AME) genes, which are important in generation of aminoglycoside resistance, were detected by PCR. Of the isolates, 60.98% carried AME genes and 38.05% carried commensal multidrug resistance genes. Therefore, resistance of avian E. coli to aminoglycoside antibiotics is very serious in North China, perhaps due to the existence of resistance genes.

Nanostructuring polymeric materials by templating strategies

This contribution summarizes efforts in designing, assembling/synthesizing, and structurally and functionally characterizing nanostructured materials using anodized aluminum oxide (AAO) as a thin-film template. Optical waveguide spectroscopy, using a nanoporous template as the guiding structure, is a particularly powerful analytical tool. The layer-by-layer approach for the fabrication of multilayer assemblies is shown to allow the fabrication of nanotube arrays. In addition to using dendrimers as building blocks, semiconducting nanomaterial (e.g., quantum dot) hybrid architectures with very interesting photophysical properties can be assembled. These can be employed, for example, in biosensing applications. Other strategies for using the AAO layers as templates include the growth of polymeric nanorod arrays from different functional monomers, which, after the dissolution of the template, are still able to guide light. This opens up novel concepts for integrated optics platforms with nanostructured materials.

CYP2D6 inhibition in patients treated with sertraline

Sertraline, a selective serotonin reuptake inhibitor used to treat depression, inhibits CYP2D6 in vitro (Ki = 1.2 microM) less potently than fluoxetine (Ki = 0.15 microM). To determine the extent and time course of CYP2D6 inhibition in patients, six males (mean age: 40 years, range: 29-64 years), who were starting treatment for depression with sertraline, were phenotyped on five occasions (once before treatment and approximately 3, 7, 14, and 21 days later). Phenotype status was determined using oral dextromethorphan (30 mg) by calculating the urinary ratio of O-demethylated metabolites to parent drug (i.e., log ODMR). CYP2D6 genotype was determined by leukocyte DNA analysis using polymerase chain reaction amplification. Compliance was confirmed by sertraline plasma levels. Daily sertraline dosages ranged from 50 to 150 mg. Genotype results indicated all subjects were extensive metabolizers (four homozygous wild type [wt], two heterozygous wt/B mutation). Phenotype results showed that CYP2D6 inhibition in patients treated with sertraline appeared to be related to baseline CYP2D6 activity and sertraline dosage. Some patients with high CYP2D6 activity can demonstrate inhibition with sertraline dosages as low as 50 mg.

Striatal 3,4-dihydroxyphenylalanine decarboxylase in aging: disparity between postmortem and positron emission tomography studies?

Recent positron emission tomography (PET) studies using 3,4-[18F]fluorodihydroxyphenylalanine ([18F]fluorodopa) have reported little or no decrement in dopaminergic function in human striatum (caudate and putamen) during aging. In contrast, previous postmortem studies have reported marked age-dependent decreases in the activity of dopa decarboxylase (DDC), a variable upon which the PET determinations depend. Using quantitative blot immunolabeling techniques, we measured DDC protein concentrations in postmortem striata of 28 neurologically normal subjects ranging in age from 17 to 103 years. We found a significant, albeit modest, age-dependent decrease in the concentration of DDC protein in caudate (r = -0.50, p < 0.05) but not in putamen (r = -0.16, p > 0.05), with mean values of the 87-year-old group being 27% (caudate) and 12% (putamen) lower than those of the 30-year-old group. The absence of a robust effect of aging upon striatal DDC protein is consistent with the [18F]fluorodopa-PET studies that report either no change or only a relatively small decrease in striatal 18F accumulation during aging. To the extent that aging is associated with a substantial loss of striatal dopaminergic nerve terminals, the present results also suggest that DDC protein synthesis may be upregulated in those dopaminergic neurons that survive the aging process and, therefore, that striatal [18F]fluorodopa uptake indices may provide an overestimate of the number of dopaminergic nerve terminals during physiological aging.

Striatal dihydroxyphenylalanine decarboxylase and tyrosine hydroxylase protein in idiopathic Parkinson's disease and dominantly inherited olivopontocerebellar atrophy

We measured the levels of dopamine, tyrosine hydroxylase (TH) protein, and dihydroxyphenylalanine (DOPA) decarboxylase (DDC) protein in the striatum of 10 patients with idiopathic Parkinson's disease (PD) and 23 patients with dominantly inherited olivopontocerebellar atrophy (OPCA). The levels of dopamine were markedly reduced (2% of control) in the striatum of the patients with PD, whereas striatal dopamine in the patients with OPCA ranged from normal (> 60% of control) to moderately reduced (20-60% of control) to severely depleted (< 20% of control). Both TH and DDC protein levels were significantly lower than those of the controls in the striatum of all of the patients with PD and in the subgroup of patients with OPCA having severely depleted dopamine. In contradistinction, TH but not DDC protein levels were reduced in those patients with OPCA having moderately reduced dopamine levels. This suggests that in the early stage of nigrostriatal dopamine neurone degeneration, DDC levels may be less susceptible to neurodegenerative influences than is TH synthesis or, alternatively, DDC synthesis may be more aggressively upregulated. Unexpectedly, from the blot immunolabeling analysis an additional DDC-immunoreactive band of slightly lower apparent molecular mass was detected in two of the patients with PD and in 12 of the patients with OPCA. This additional DDC band, which was not present in any of the control subjects, may reflect posttranslational modification(s) of DDC related to the neurodegenerative process.

Dopa-responsive dystonia: pathological and biochemical observations in a case

We report the first neuropathological and neurochemical study of a patient with dopa-responsive dystonia. She had onset of foot dystonia at age 5 years and by age 8 years it was generalized with prominent right leg and arm involvement. On levodopa 750 mg daily she had complete symptomatic improvement that was sustained for 11 years until death. Pathological studies revealed normal numbers of hypopigmented substantia nigra neurons, normal tyrosine hydroxylase (TH) immunoreactivity and TH protein in the SN, no inclusion bodies or gliosis, and no evidence of a degenerative process in the striatum. Biochemical studies revealed reduced dopamine in the substantia nigra and striatum (8% in the putamen and 18% of control in the caudate) with a similar but not identical subregional distribution as in idiopathic Parkinson's disease. In the striatum, TH protein and TH activity was reduced, with the loss more pronounced in the putamen than the caudate. The GBR 12935 binding to DA transporter was normal in the caudate and at the lower end of the range of control values in the putamen. We conclude that disturbed dopamine synthetic capacity or a reduced arborization of striatal dopamine terminals may be the major disturbance in dopa-responsive dystonia.

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine-resistant, flat-cell PC12 variants having a partial loss of transformed phenotype

We have cloned and characterized two variants of PC12 cells. MPT1 cells were selected by their resistance to 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), and variant 2068 was isolated nonselectively as a large, flat-cell variant commonly occurring in PC12 cultures. Variant 2068 cells also exhibit resistance to MPTP. Karyotype analysis revealed that these variants are true derivatives of wild-type PC12 cells; however, each variant is tetraploid, whereas the wild-type parent is diploid. The two variants contain an altered level and composition of lactate dehydrogenase isoenzymes, which could account for a previously described difference in lactate metabolism. Both variants exhibit a partial loss of transformed phenotype in culture in that they are nonrefractile, grow in monolayers, and fail to multiply in soft agar. We suggest that this alteration in transformed phenotype may result in altered mitochondria and lactate dehydrogenase and thus account for their resistance to MPTP. Compared with wild-type PC12 cells, MPT1 cells have a decreased level of fos mRNA and an increased level of myc mRNA; the latter results from an increased level of transcription of exon 1 of the myc gene. Studies with hybrid cells obtained by fusing MPT1 cells with wild-type-like cells show that most, but not all, of the parameters of the MPT1 phenotype predominate.

Phosphotyrosine-containing lactate dehydrogenase is restricted to the nuclei of PC12 pheochromocytoma cells

There are five lactate dehydrogenase (LDH) isoenzymes, composed of various combinations of two types of subunits. LDH-5, which contains only the LDH A subunit, is known to be present in both the cytoplasm and the nucleus, to act as a single-stranded DNA-binding protein possibly functioning in transcription and/or replication, and to undergo phosphorylation of tyrosine 238 in approximately 1% of the enzyme after cell transformation by certain tumor viruses. We have characterized LDH from wild-type PC12 pheochromocytoma cells and from a PC12 variant (MPT1) that exhibits altered lactate metabolism and altered expression of multiple genes. Wild-type and MPT1 cells contain different proportions of LDH isoenzymes, with LDH-5 being more predominant in wild-type cells than in the variant. A small fraction of LDH from PC12 cells contains phosphotyrosine. Approximately 99% of the total LDH activity is located in the cytoplasm, but all of the phosphotyrosine-containing LDH is located in the nucleus. Furthermore, essentially all of the nuclear LDH contains phosphotyrosine. These results suggest that tyrosine phosphorylation can affect its role in the nucleus.