Data mining of reference intervals for serum creatinine: an improvement in glomerular filtration rate estimating equations based on Q-values

OBJECTIVES

Glomerular filtration rate (GFR) estimating equations based on rescaled serum creatinine (SCr/Q) have shown better performance, where Q represents the median SCr for age- and sex-specific healthy populations. However, there remains a scarcity of investigations in China to determine this value. We aimed to develop Chinese age- and sex-specific reference intervals (RIs) and Q-values for SCr and to validate the equations incorporating new Q-values.

METHODS

We included 117,345 adults from five centers for establishing RIs and Q-values, and 3,692 participants with reference GFR (rGFR, 99mTc-DTPA renal dynamic imaging measurement) for validation. Appropriate age partitioning was determined using the decision tree method. Lower and upper reference limits and medians were calculated using the refineR algorithm, and Q-values were determined accordingly. We evaluated the full age spectrum (FAS) and European Kidney Function Consortium (EKFC) equations incorporating different Q-values considering bias, precision (interquartile range, IQR), and accuracy (percentage of estimates within ±20 % [P20] and ±30 % [P30] of rGFR).

RESULTS

RIs for males were: 18-79 years, 55.53-92.50 μmol/L; ≥80 years, 54.41-96.43 μmol/L. RIs for females were: 18-59 years, 40.42-69.73 μmol/L; 60-79 years, 41.16-73.69 μmol/L; ≥80 years, 46.50-73.20 μmol/L. Q-values were set at 73.82 μmol/L (0.84 mg/dL) for males and 53.80 μmol/L (0.61 mg/dL) for females. After validation, we found that the adjusted equations exhibit less bias, improved precision and accuracy, and increased agreement of GFR categories.

CONCLUSIONS

We determined Chinese age- and sex-specific RIs and Q-values for SCr. The adjustable Q-values provide an effective alternative to obtain valid equations for estimating GFR.

Assessment of the 2023 European Kidney Function Consortium (EKFC) equations in a Chinese adult population

OBJECTIVES

The European Kidney Function Consortium (EKFC) developed two novel equations in 2023 for estimating glomerular filtration rate (GFR): one sex-free cystatin C-based equation (EKFCCys) and one creatinine-cystatin C combined equation (EKFCCr-Cys). This study compared their performance with the previous creatinine-based EKFC equation (EKFCCr) and commonly used Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) and Berlin Initiative Study (BIS) equations in Chinese adults.

METHODS

A total of 2,438 Chinese adults (mean age=53.04 years) who underwent the 99mTc-DTPA renal dynamic imaging for reference GFR (rGFR) were included. Diagnostic value was evaluated using correlation coefficients, sensitivity, specificity, and area under the receiver operating characteristic curve (ROCAUC). Performance was assessed in terms of bias, precision (interquartile range of the median difference [IQR]), accuracy (percentage of estimates ±30 % of rGFR [P30], and root-mean-square error [RMSE]) across age, sex, and rGFR subgroups. Gender differences in bias and P30 were also analyzed.

RESULTS

Average rGFR was 73.37 mL/min/1.73 m2. EKFC equations showed stronger correlations and larger AUCs compared to the parallel CKD-EPI equations, with EKFCCr-Cys demonstrating the greatest improvement (R=0.771, ROCAUC=0.913). Concerning bias, precision, and accuracy, EKFC equations consistently outperformed CKD-EPI equations. EKFCCr-Cys and EKFCCr performed acceptably well in the entire population and were equivalent to BIS equations in the elderly. All equations, including EKFCCys, showed similar P30 accuracy across sexes.

CONCLUSIONS

EKFC equations provided a reasonable alternative for estimating GFR in the Chinese adult population. While EKFCCys did not outperform EKFCCr, EKFCCr-Cys improved the accuracy of single-marker equations.

A case of chronic kidney disease patient with rapid deterioration of renal function, hair loss, and spontaneous resolution of facial warts after COVID-19 infection

Background

Individuals with pre-existing chronic kidney disease (CKD) are at an increased risk of experiencing severe symptoms if infected with COVID-19. This report presents the case of a patient with CKD who contracted COVID-19 and subsequently experienced rapid deterioration of kidney function, hair loss, and spontaneous remission of facial warts.

Case presentation

A 60-year-old Chinese man with a decade-long history of abnormal serum creatinine (Scr) levels and recently heightened fatigue sought treatment. The disease was previously managed and deemed resolved in 2020. However, when he contracted the novel coronavirus on December 20, 2022, he experienced persistent fatigue without other symptoms. In early January 2023, Scr levels was examined as more than 300 μmol/L. This was followed by hair loss, including eyebrows and lashes, and the spontaneous resolution of a longstanding facial wart. During this period, although the patient received kidney-protecting drugs and a lifestyle optimization, Scr increased continuously and the disease eventually progressed to the uremic stage. As the patient still had relatively abundant urine volume, the patient chose peritoneal dialysis treatment. At a two-month follow-up, he had adhered to the CAPD protocol without complications and his hair had begun to regrow. After eight months, his hair had mostly regrown, and his Scr levels kept stable.

Conclusion

This case may represent the inaugural instance of CKD patients experiencing rapid deterioration of renal function, hair loss, and spontaneous remission of common warts. The underlying mechanisms of this unique phenomenon warrant further researches and debate.

Multiple and large simple renal cysts are associated with glomerular filtration rate decline: a cross-sectional study of Chinese population

BACKGROUND

Although simple renal cyst (SRC) is a kind of structural alterations of kidney with age, the relationship between SRC and renal function is still obscure. We investigated the relationship between SRC and renal function in Chinese population.

METHODS

The medical records of 41,842 individuals who underwent physical examinations at the Health Check-up Center at our institution in 2018 were reviewed. According to whether with SRC, they were divided into no-SRC and SRC groups. SRCs were classified into subgroups based on number (< 2 vs. ≥ 2) and size (< 2 cm vs. ≥ 2 cm). Logistic regression was used to examine the relationship between SRC and estimated glomerular filtration rate (eGFR).

RESULTS

Multinomial logistic regression analysis showed that the adjusted odds ratio (OR) for eGFR slight decline in subjects with SRC was 1.26(95% confidence interval (95% CI):1.17-1.35, p < 0.001), and the OR for eGFR severe decline was 1.35(95% CI: 1.16-1.56, p < 0.001) compared with no-SRC. The adjusted OR of SRC number ≥ 2 and ≥ 2 cm on the risk of eGFR severe decline was the highest (OR:1.68, 95% CI:1.25-2.23, p < 0.01) of four SRC subgroups.

CONCLUSIONS

SRC is related to eGFR decline, especially when the person with one more SRCs and the size of SRC is more than 2 cm. SRC could be a warning sign for clinicians to judge the decline of renal function.

Different equations for estimating age-related changes of glomerular filtration rate in the healthy population

BACKGROUND

Identifying age-related trend of estimated glomerular filtration rate (eGFR) is necessary to assess whether kidney function is healthily aging. This study aimed to investigate the application of CKD-EPI, FAS, and Xiangya equations for the aging estimation of eGFR in the healthy Chinese individuals.

METHODS

A total of 36,911 healthy individuals were enrolled in this study. We grouped every ten years to observe the trend of eGFR with aging and investigated decline rate of it by general linear regression analysis in each age-groups. Agreement between equations was determined by intraclass correlation coefficient (ICC) and Bland-Altman plot. We calculated reference interval in each age-group. We further analyzed above statistical indicators in males and females.

RESULTS

The eGFR by CKD-EPI, and Xiangya equation started to decline from the age of 18. Whereas eGFR by FAS equation remained stable under 40 years, then decreased more rapidly. Compared with males, the females had a higher level but a faster decline rate of eGFR with aging. Agreement analysis revealed good agreement between CKD-EPI and FAS equations (ICC 0.818-0.920). Agreement between Xiangya and CKD-EPI or FAS equations was poor to moderate in most of the population under 70 years old (ICC 0.282-0.786), but good in individuals above 70 years (ICC 0.769-0.881).

CONCLUSIONS

The trend of eGFR with aging was different by CKD-EPI, FAS, and Xiangya equations in the healthy Chinese. It may be necessary to take these equations- or age-related differences into consideration when assessing kidney function in primary health care and clinical practice.

Comparison of glomerular filtration rate estimating equations in older adults: A systematic review and meta-analysis

BACKGROUND

Debates persist regarding the performance of existing glomerular filtration rate (GFR) estimating equations in older individuals. We performed this meta-analysis to assess the accuracy and bias of six commonly used equations, including the Chronic Kidney Disease Epidemiology Collaboration creatinine equation (CKD-EPICr) and its combination with cystatin C (CKD-EPICr-Cys), with the corresponding pair of the Berlin Initiative Study equations (BIS1 and BIS2) and the Full Age Spectrum equations (FASCr and FASCr-Cys).

METHODS

PubMed and the Cochrane Library were searched for studies comparing estimated GFR (eGFR) with measured GFR (mGFR). We analyzed the difference in P30 and bias among the six equations and investigated subgroups based on the area (Asian and non-Asian), mean age (60-74 years and ≥75 years), and levels of mean mGFR (<45 mL/min/1.73m2 and ≥45 mL/min/1.73m2).

RESULTS

27 studies with 18,112 participants were included, all reporting P30 and bias. BIS1 and FASCr exhibited significantly higher P30 than CKD-EPICr. While no significant differences were observed between FASCr and BIS1, or among the three combined equations in terms of either P30 or bias. Subgroup analyses revealed FASCr and FASCr-Cys achieved better results in most situations. However, in the subgroup of mGFR<45 mL/min/1.73m2, CKD-EPICr-Cys had relatively higher P30 and significantly smaller bias.

CONCLUSIONS

Overall, BIS and FAS provided relatively more accurate estimates of GFR than CKD-EPI in older adults. FASCr and FASCr-Cys may be better suited for various conditions, while CKD-EPICr-Cys would be a better option for older individuals with impaired renal function.

Validation of the European Kidney Function Consortium Equation in Chinese Adult Population: An Equation Standing on the Shoulders of Predecessors

BACKGROUND

Equations based on serum creatinine (SCr) have been extensively applied to estimate glomerular filtration rate (GFR), but their performance is debatable. In 2021, the European Kidney Function Consortium (EKFC) published one novel SCr-based formula, which combined the feature of Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) and full age spectrum (FAS) equations, but its potential applications remain unknown. We seek to assess the appropriateness of the three equations in Chinese adults.

METHODS

A total of 3,692 participants (median age, 54 years) were included. Reference GFR (rGFR) was measured by the 99mTc-DTPA renal dynamic imaging method. Estimated GFR (eGFR) was calculated by the CKD-EPI, FAS, and EKFC equations. Correlation coefficients and Bland-Altman analysis were adopted to evaluate their validity. The performance was assessed in subgroups according to age, sex, rGFR, and SCr, considering the bias, accuracy, and precision.

RESULTS

The average rGFR was 74.2 mL/min/1.73 m2. eGFR by EKFC showed a relatively stronger correlation with rGFR (R = 0.749) and a larger area under the receiver operating characteristic curve (0.902). EKFC was significantly less biased and exhibited the highest P30 in the entire population (bias = 3.61, P30 = 73.3%). It also performed well in all analyzed subgroups, especially in participants with normal or slightly impaired renal function (rGFR≥60 mL/min/1.73 m2), and low SCr.

CONCLUSIONS

Compared to the other two SCr-based formulas, EKFC performed better in the Chinese. Thus, it might serve as a good alternative, until a more suitable formula is developed for the Chinese population.

METTL3 alleviates D-gal-induced renal tubular epithelial cellular senescence via promoting miR-181a maturation

Methyltransferase-like protein 3 (METTL3) mediated N6-Methyladenosine (m⁶A) modification has been implicated in many physiological and pathological processes. However, its function and mechanism in kidney aging are not entirely clear. Here, we investigated changes in m⁶A levels of aging kidneys and the role of METTL3 in senescent renal tubular epithelial cells and its potential mechanisms. First, we used the naturally aged mouse model and the D-galactose (D-gal)-induced aged mouse model. Dot blot and m⁶A RNA methylation quantification showed significantly decreased m⁶A levels in both models. In addition, we observed that METTL3 was down-regulated in D-gal-induced senescent human renal tubular epithelial cell line (HK-2). METTL3 reduction was associated with senescence-related phenotypes of HK-2 cells. We also found that miR-181a-5p attenuated HK-2 senescence by targeting the NF-κB pathway. Moreover, METTL3 was able to promote the maturation of miR-181a-5p and then inhibited the expression of NF-κB and IL-1α. Taken together, we demonstrate that the METTL3/miR-181a-5p/NF-κB axis counteracts HK-2 senescence. Our results suggest that METTL3 may be a novel biomarker and a potential therapy target for kidney aging.

Thyroid function and age-related decline in kidney function in older Chinese adults: a cross-sectional study

Background

Thyroid function may be a factor affecting kidney function in the general population. Kidney and thyroid function vary with age; therefore, the association between thyroid function and decreased kidney function in older adults may be different from that in younger adults and remains controversial. This study aimed to estimate the association between normal-range thyroid function and age-related decline in kidney function in older Chinese adults.

Methods

A total of 15,653 adults, of whom 23.2% (N = 3624) were older adults (age≧65 years), were collected at the Health Management Center of the First Affiliated Hospital of Nanjing Medical University from January 2018 to January 2020. Basic demographic information was collected by a physician-administered questionnaire. The estimated glomerular filtration rate (eGFR) was calculated using the CKD-EPI formula. Trends in thyroid function with age were shown by means of free triiodothyronine (FT3), free thyroxine (FT4), and thyroid-stimulating hormone (TSH) in subgroups every ten years. The association between kidney function and thyroid function was estimated by multiple linear regression using β value and by multivariable logistic regression models using odds ratios (OR) after adjusting for age, gender, body mass index, and serum urine acid.

Results

In the older population, TSH tended to increase with age and FT3 tended to decrease, whereas FT4 was relatively stable. eGFR decreased significantly with increasing TSH (β = -0.081) and decreasing FT3 (β = 0.083) concentrations. Compared with those in the lowest quartile of FT3 (3.10–4.47 pmol/L), the prevalence of eGFR < 75 ml/min/1.73m² decreased significantly by 22.0% for those with FT3 of 4.47–4.81 pmol/L, 27.6% for those with FT3 of 4.82–5.20 pmol/L, and 34.9% for those with FT3 of 5.21–6.8 pmol/L in older individuals (P for trend < .001). The OR was 1.315 (P: 0.025) in subjects with high-normal TSH, using low-normal TSH as a reference. The prevalence of reduced kidney function was not significantly associated with FT4 within the reference range. Similar results were found in association between the prevalence of eGFR < 60 ml/min/1.73m² and thyroid function.

Conclusions

This study demonstrated a significant association between kidney function and thyroid function, particularly FT3, in the older population. Clinicians may need to pay more attention to the assessment and follow-up of kidney function in older individuals with low-normal FT3 and high-normal TSH.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12877-022-02904-z.

A risk scoring system for the decreased glomerular filtration rate in Chinese general population

Objective

The aim of this study was to establish a risk scoring system for the decreased glomerular filtration rate (GFR) in Chinese general population.

Methods

Totally 781 participants who underwent a health checkup in The First Affiliated Hospital of Nanjing Medical University from January to September 2017 were involved in the study. Significant variables chosen by multivariable logistic regression analysis were allocated the integral scores in proportion to its odds ratio (OR), and then the risk of decreased GFR was assessed based on the scores.

Results

The people with abnormal homocysteine (Hcy) level (OR: 1.534, 95% confidential interval [CI]: 1.075‐2.190, P = .018), males (OR: 2.054, 95%CI: 1.365‐3.092, P < .001), and those at the age of 46‐52 years (OR: 2.943, 95%CI: 1.546‐5.605, P = .001), 52‐59 years (OR: 3.664, 95%CI: 1.937‐6.931, P < .001) and ≥59 years (OR: 13.452, 95%CI: 7.339‐24.657, P < .001) were subjected to GFR reduction. These three variables were allocated the integral scores in proportion to its OR, and four risk categories were divided according to the scores. The prevalence of the decreased GFR in people with low (score 0‐4, n = 8), below the average (score 4‐6, n = 37), above the average (score 6‐13, n = 47), and high risks (score ≥ 13, n = 103) was 5.26%, 16.89%, 22.93% and 50.24%, respectively, and this prevalence raised with the increase of scores (P < .001).

Conclusions

A risk scoring system is developed in this study, which may offer a specific risk stratification for GFR reduction in Chinese general population.

Mild cognitive impairment in maintenance hemodialysis patients: a cross-sectional survey and cohort study

Introduction

Few studies focused on mild cognitive impairment (MCI) in maintenance hemodialysis (MHD) patients. This study was conducted to survey the prevalence, the potent risk factors of MCI in MHD patients, and further observe the progress of MCI in a period of 6 months.

Methodology

Mini-Mental State Examination, and Montreal Cognitive Assessment were used to assess cognitive condition. MHD patients were enrolled from The First Affiliated Hospital of Nanjing Medical University, who had a stable hemodialysis history for more than 3 months.

Results

Sixty-four MHD patients and 54 general subjects were finally included. The average age of both groups was more than 60 years. The prevalence of MCI in the MHD group was significantly higher than that in general population (60.9% vs 29.6%, P<0.05). Spearman correlation analysis indicated that MCI was related to age, comorbidities, education years, uric acid, serum albumin, and blood pressure. The prevalence and severity of MCI in the MHD group remained unchanged during the 6 months (prevalence: 59.5%–66.6%, MoCA scores: 22.9–22.5).

Conclusion

MHD patients sustain a fairly high prevalence of MCI. Multiple risk factors influence the incidence and progression of MCI in MHD patients. More attention should be paid to this special population.

Evaluation value of neutrophil gelatinase-associated lipocalin for the renal dysfunction of patients with chronic kidney disease: A meta-analysis

OBJECTIVE

The role of neutrophil gelatinase-associated lipocalin (NGAL) for the evaluation of renal function in chronic kidney disease (CKD) has not yet to be determined. We aimed to perform a meta-analysis exploring the correlation between NGAL and glomerular filtration rate (GFR) in CKD patients, and to further identify factors affecting NGAL's performance.

METHODS

Studies dated before November 2017 were retrieved from PubMed, Embase, Web of Science, and the Cochrane Library. A total of 28 relevant studies (involving 3082 patients from 17 countries) were included. The second version of the Quality Assessment for Studies of Diagnostic Accuracy demonstrated that no significant bias had influenced the methodological quality of the included studies.

RESULTS

Neutrophil gelatinase-associated lipocalin showed a strong negative correlation with measured glomerular filtration rate (mGFR). The pooled correlation coefficient (r) with corresponding 95% confidence intervals for the correlation between serum NGAL (sNGAL) and GFR was -0.48, meanwhile that for urine NGAL (uNGAL) and GFR was -0.34. However, NGAL's performance is different in subgroups restricted by clinical settings, race, sex, age, and staging of renal function.

CONCLUSION

Neutrophil gelatinase-associated lipocalin could be a renal function evaluation marker for patients with renal dysfunction in CKD. Compared with uNGAL, there was a significant negative correlation between sNGAL and GFR. The performances of sNGAL and uNGAL were restricted by clinical factors that should be considered in regards to the sampling source selection.

[Blomia tropicalis is found in a flour warehouse of a food factory in a civil aviation airport]

Objective To investigate whether there is Blomia tropicalis breeding in the flour warehouse of food factory in a civil aviation airport, and, if there is, to observe the morphological structure of the mite. Methods The flour samples were collected from the flour warehouse of food factory in a civil aviation airport. The breeding mites were isolated from the samples by direct microscopy and made into specimens to observe with a light microscope. Results Female Blomia tropicalis was found in the collected flour samples. Under the microscope, the mite was nearly spherical, and it had no tergum and claw. Its apodemeⅠ was developed and connected in the midline. The reproductive hole was located between the foot Ⅲ and IV level and was covered with a pair of oblique genital folds. The foot Ⅲ and Ⅳ had no solenoids. The copulatory pouch was a long, slightly curved tube, extending from the end of the mite. ConclusionsBlomia tropicalis has been found in the flour warehouse of a food factory in the civil aviation airport. The main distinguishing feature of this mite is that it has no tergum, its feet have no pectinate inferior tarsus scales or claw, the feetⅠgenu has only one solenidia, and feet Ⅲ and Ⅳ have no solenidias.

Predictive value of serum cystatin C for acute kidney injury in adults: a meta-analysis of prospective cohort trials

The role of serum cystatin C (Scys) for the detection of acute kidney injury (AKI) has not been fully discussed. This meta-analysis was aimed to investigate the overall diagnostic accuracy of Scys for AKI in adults, and further identify factors affecting its performance. Studies before Sept. 2016 were retrieved from PubMed, Embase, Web of Science and the Cochrane Library. A total of 30 prospective cohort studies (involving 4247 adults from 15 countries, 982 patients occurring AKI) were included. The revised Quality Assessment for Studies of Diagnostic Accuracy (QUADAS-2) tools demonstrated no significant bias had influenced the methodological quality of the included studies. Scys showed a high predictive power for all-cause AKI, that the area under the receiver operating characteristic curve was 0.89. The detailed assessment parameters, such as sensitivity, specificity, positive likelihood ratio, negative likelihood ratio and diagnostic odds ratio for Scys were 0.82, 0.82, 4.6, 0.22 and 21, respectively. Although Scys could be slightly influenced by the following factors: settings, AKI diagnostic criteria, ethnicity, determination method, age and gender, these factors above did not reach statistically significance. In conclusion, Scys could be a vital promising marker to screen out AKI.

Estimation of standard liver volume in Chinese adult living donors

AIM

To determine a formula predicting the standard liver volume based on body surface area (BSA) or body weight in Chinese adults.

MATERIALS AND METHODS

A total of 115 consecutive right-lobe living donors not including the middle hepatic vein underwent right hemi-hepatectomy. No organs were used from prisoners, and no subjects were prisoners. Donor anthropometric data including age, gender, body weight, and body height were recorded prospectively. The weights and volumes of the right lobe liver grafts were measured at the back table. Liver weights and volumes were calculated from the right lobe graft weight and volume obtained at the back table, divided by the proportion of the right lobe on computed tomography. By simple linear regression analysis and stepwise multiple linear regression analysis, we correlated calculated liver volume and body height, body weight, or body surface area.

RESULTS

The subjects had a mean age of 35.97 +/- 9.6 years, and a female-to-male ratio of 60:55. The mean volume of the right lobe was 727.47 +/- 136.17 mL, occupying 55.59% +/- 6.70% of the whole liver by computed tomography. The volume of the right lobe was 581.73 +/- 96.137 mL, and the estimated liver volume was 1053.08 +/- 167.56 mL. Females of the same body weight showed a slightly lower liver weight. By simple linear regression analysis and stepwise multiple linear regression analysis, a formula was derived based on body weight. All formulae except the Hong Kong formula overestimated liver volume compared to this formula.

CONCLUSIONS

The formula of standard liver volume, SLV (mL) = 11.508 x body weight (kg) + 334.024, may be applied to estimate liver volumes in Chinese adults.

Isothermal titration calorimetry - a new method for the quantification of microbial degradation of trace pollutants

The environmental fate and, in particular, biodegradation rates of hydrophobic organic compounds (HOC) are of high interest due to the ubiquity, persistence, and potential health effects of these compounds. HOC tend to interact with bioreactor materials and sampling devices and are frequently volatile, so that conventionally derived degradation parameters are often biased. We report on the development and validation of a novel calorimetric approach that serves to gain real time information on the kinetics and the physiology of HOC bioconversion in aqueous systems while overcoming weaknesses of conventional biodegradation experiments. Soil bacteria Mycobacterium frederiksbergense LB501T, Rhodococcus erythropolis K2-3 and Pseudomonas putida G7 were exposed to pulsed titrations of dissolved anthracene, 4-(2,4-dichlorophenoxy)butyric acid or naphthalene, respectively, and the thermal responses were monitored. The combinations of strains and pollutants were selected as examples for complete and partial biodegradation and complete degradation with storage product formation, respectively. Heat production signals were interpreted thermodynamically and in terms of Michaelis-Menten kinetics. The half-saturation constant k(D) and the degradation rate r(D)(Max) were derived. Comparison with conventional methods shows the suitability to extract kinetic degradation parameters of organic trace pollutants from simple ITC experiments, while thermodynamic interpretation provided further information about the metabolic fate of HOC compounds.

Effect of feeding allowance level on embryonic survival, IGF-1, insulin, GH, leptin and progesterone secretion in early pregnancy gilts

The present experiment was conducted to evaluate the effects of feeding allowance level on embryonic survival, uterine development and reproductive hormone secretion in early gestation gilts. A total of 54 F1 crosses of Landrace x Large white gilts were randomly allocated to three treatment groups of high (H, 2 x maintenance), medium (M, 1.2 x maintenance) and low (L, 0.6 x maintenance) feeding level after mating. Blood samples and uterine flushings were collected on day 12, 25 and 35 of pregnancy, and embryonic survival rate was estimated. Concentrations of insulin-like growth factor I (IGF)-1, insulin, growth harmone (GH), leptin and progesterone in serum and uterine flushings were determined by enzyme-linked immunosorbent assay. Embryonic survival was affected by dietary treatment; total number of viable embryos and embryo survival of group M were higher than other groups in the early pregnancy (p < 0.05). Greater foetal weight in M gilts was achieved when gestation advanced to day 35 (p < 0.05), though there was no difference on day 25 of pregnancy among treatments. No appreciable differences were observed in the crown-rump length on day 25 and 35 of pregnancy among groups. Greater weight of uterus and products of conception were identified in M gilts compared with group H and L (p = 0.024 and p = 0.005, respectively) on day 25 of pregnancy. The hormone level was greatly affected by feeding allowance level. In serum, concentrations of IGF-1, leptin and insulin tended to be greater in H than in M and L during the early gestation, while concentrations of GH were greater in M and progesterone were the lowest in H. At the same time, feed allowance level affected the concentration of IGF-1, insulin, GH, leptin and progesterone in uterine flushings. These data demonstrated that feed allowance level after mating has important consequence on embryo survival, embryo development and uterine development, possibly mediated by nutrition level inducing changes in concentrations of reproductive hormones and/or intermediary metabolites in early pregnancy.

Blood–retinal barrier disruption and ultrastructural changes in the hypoxic retina in adult rats: the beneficial effect of melatonin administration

Reactive changes in astrocytes and Müller cells in the retina of adult rats subjected to hypoxia were investigated. Along with this, the integrity of the blood-retinal barrier (BRB) was assessed using fluorescent and electron-dense tracers. In hypoxic rats, mRNA and protein expression of glial fibrillary acidic protein (GFAP) and aquaporin-4 (AQ4) were significantly increased. AQ4 immunoreactive cells were identified as astrocytes and Müller cells by double immunofluorescence labelling. Another alteration in the hypoxic retina was marked reduction in melatonin content compared to controls. In this connection, administration of exogenous melatonin reduced the tissue concentration of vascular endothelial growth factor (VEGF) and nitric oxide (NO); both were elevated in hypoxic rats. A major structural change in the hypoxic retina was swelling of astrocyte and Müller cell processes but this was noticeably attenuated after melatonin administration. Following an intraperitoneal or intravenous injection of rhodamine isothiocyanate (RhIC) or horseradish peroxidase (HRP), leakage of both tracers was observed in the retina in hypoxic rats but not in the controls, indicating that the functional integrity of the BRB is compromised in hypoxia/reoxygenation. It is suggested that enhanced tissue concentration of VEGF and NO production in the hypoxic retina contribute to increased permeability of the retinal blood vessels. The concurrent up-regulation of AQ4, a water-transporting protein, in astrocytes and Müller cells in hypoxia suggests its involvement in oedema formation. Since melatonin effectively reduced the vascular permeability in the retina of hypoxic rats, as evidenced by reduced leakage of RhIC, we suggest that its administration may be of potential benefit in the management of retinal oedema associated with retinal hypoxia.

Growth-associated gene expression profiles by microarray analysis of trophoblast of molar pregnancies and normal villi

We used microarray analysis to investigate expression profiles of 589 known genes committed to cell growth control to characterize regulatory circuitry for cell proliferation in complete moles (CMs). CMs are characterized by hyperplastic trophoblast and have a high propensity to give rise to choriocarcinoma. Characteristic alterations in gene expression profiles were observed when compared with normal villi. Fifty-seven genes were significantly up-regulated in CMs and involved the Ras-Map kinase 3, Jak-STAT5, and Wnt signal pathways, implicating growth factor or cytokine-mediated signal pathways in the trophoblastic hyperplasia of CMs. Several genes associated with anti-apoptosis, cell structuring, and/or cell attachment were also up-regulated in CMs. In contrast, relatively fewer genes were down-regulated and these involved IGFBPs, versican, interleukin-1, tumor necrosis factor receptor, CD44, and RAD52. Genes identified in this study may elucidate regulation mechanisms of trophoblastic proliferation and mechanisms causing a pathological phenotype in CMs.

In vitro development of caprine ovarian preantral follicles

The in vitro growth and developmental pattern of caprine preantral follicles cultured in agar gel was observed. Preantral follicles 50 to 150 microm in diameter were isolated from prepuberal goat ovaries by treatment with collagenase and DNase. The isolated preantral follicles were cultured in agar gel for up to 14 days. A group of 10 follicles in different developmental stages was cultured in a culture well coated with 0.6% agar gel and filled with DMEM medium supplemented with FCS (10%), hypoxanthine (2 mmol/mL), dbcAMP (2 mmol/mL), FSH (100 ng/mL), insulin-transferrin-selenium (ITS) (50 ng/mL), IGF-1 (50 ng/mL), hydrocortisone (40 ng/mL) and antibiotics. Follicle viability was determined under an inverted phase-contrast microscope according to morphological and histological criteria, and follicle growth was assessed by their size and appearance. The results showed that the three-dimensional structures and forms of follicles were basically maintained intact during culture. Primary follicles developed into secondary follicles and a few of them into antral follicles. A large portion of secondary follicles entered the antral stage, and oocytes also acquired growth. The formation of theca lamina and zona pellucida was observed. The survival capacity of secondary follicles was greater than primary follicles. The survival rates for primary and secondary follicles were 11.36% (5/44) and 71.16% (53/74), respectively. During in vitro development the follicles demonstrated dominance. This experiment revealed the preliminary characteristics of the in vitro development of caprine preantral follicles.

Nuclear-cytoplasmic interaction and development of goat embryos reconstructed by nuclear transplantation: production of goats by serially cloning embryos

The time of pronuclear formation of in vivo-matured oocytes was examined. Maturation-promoting factor (MPF) activity in enucleated and electrically activated oocytes was checked by assessment of nuclear envelope breakdown (NEBD) of fused blastomeres. The effect of stage of the cell cycle of donor cells and recipient oocytes on DNA synthesis and development of reconstructed embryos was studied. MPF activity declined rapidly to approximately 63.2% at 1 h, to 9.7% at 5 h, and to the level at which NEBD cannot occur at 7 h postactivation. All blastomeres that were fused at the time of recipient cytoplasm activation underwent NEBD and subsequent DNA synthesis. However, when blastomeres were fused to enucleated oocytes at 7 h postactivation, no NEBD was observed; DNA was replicated in nuclei at the G1/S border, but in G2 nuclei no DNA replication was observed. The proportion of development to blastocysts of reconstructed goat embryos increased with the decline in MPF activity in fused recipient cytoplasm when reconstruction took place at 0-6 h postactivation of enucleated oocytes. Generations 1, 2, 3, 4, 5, and 6 of cloned goat embryos were produced by a combination of nuclear transplantation and in vitro techniques. After transfer to recipients, 45 kids were obtained, including three pairs of monozygotic twins, three series of monozygotic triplets, two series of monozygotic quadruplets, three series of monozygotic quintuplets, and one series of monozygotic heptaplets. The present study indicates that normal DNA replication of goat blastomere nuclei can be accomplished in enucleated oocytes when MPF activity is low, regardless of the stage of the cell cycle of donor nuclei; induction of NEBD and prematuration chromosome condensation is not essential for further development of reconstructed goat embryos.

A monoclonal anti-HLA-B27 antibody which is reactive with a linear sequence of the HLA-B27 protein is useful for the study of molecular mimicry

In the search for cross-reactivity between bacteria and HLA-B27, three groups of investigators have identified several bacterial envelope proteins which are reactive with the monoclonal anti-HLA-B27 antibodies B27.M1 and B27.M2. Since these two antibodies react poorly with HLA-B27-derived synthetic peptides, it is not possible to locate the reactive epitopes on the HLA-B27 using synthetic peptides. Here, we introduce Ye-2, a monoclonal anti-HLA-B27 antibody which, unlike B27.M1 and B27.M2, is reactive with a synthetic peptide derived from residues 63-84 of HLA-B27.1. Analysis with a cross-reactive peptide derived from residues 226-244 of bovine carbonic anhydrase suggests that only a few of the amino acid residues in the HLA-B27-derived peptide are responsible for the reactivity. This antibody should be a useful adjunct in a preliminary assessment of whether a bacterial protein mimics HLA-B27 in primary structure.

An experimental mouse model of Yersinia-induced reactive arthritis

An experimental animal model of Yersinia-induced arthritis was successfully developed in mice using Yersinia enterocolitica WA. In order for the Yersinia to induce arthritis the strain had to be cured of plasmid. The arthritis-susceptible mouse strains were DBA/2 and BDF1. C57B1/6, Balb/c, CBA and DBA/1 were arthritis-resistant. Both the dose of bacteria and the route of administration were critical.

A Yersinia pseudotuberculosis protein which cross-reacts with HLA-B27

The most-debated question in the investigation of the spondyloarthropathies has been whether there is molecular mimicry between host HLA-B27 antigens and the arthritis-causing pathogens. We have generated a monoclonal anti-HLA-B27 antibody in our laboratory and have used a radioimmunoassay to screen a panel of bacterial species. Two strains of Yersinia pseudotuberculosis were found to be highly reactive. The cross-reactive Yersinia component was identified by Western blot to be a 19,000 component. A preparative sodium dodecyl sulfate-polyacrylamide gel electrophoresis chromatography apparatus was constructed to isolate milligram quantities of this component. To verify that the component carried the HLA-B27-specific epitope, rabbits were hyperimmunized with the purified materials. Affinity-purified antibodies from one of the immunized rabbits indeed carried anti-HLA-B27 activity. Last, antibodies generated against synthetic peptides derived from the HLA-B27.1 amino acid sequence were tested against the Yersinia component. Positive reactivity was found with antibodies generated against a peptide spanning residues 69-83 of the HLA-B27.1 protein. Since this resides in the segment responsible for the allotypic specificity of the antigen, these experiments establish the presence of molecular mimicry to a high degree of confidence.

A Yersinia pseudotuberculosis protein which cross-reacts with HLA-B27

The most-debated question in the investigation of the spondyloarthropathies has been whether there is molecular mimicry between host HLA-B27 antigens and the arthritis-causing pathogens. We have generated a monoclonal anti-HLA-B27 antibody in our laboratory and have used a radioimmunoassay to screen a panel of bacterial species. Two strains of Yersinia pseudotuberculosis were found to be highly reactive. The cross-reactive Yersinia component was identified by Western blot to be a 19,000 component. A preparative sodium dodecyl sulfate-polyacrylamide gel electrophoresis chromatography apparatus was constructed to isolate milligram quantities of this component. To verify that the component carried the HLA-B27-specific epitope, rabbits were hyperimmunized with the purified materials. Affinity-purified antibodies from one of the immunized rabbits indeed carried anti-HLA-B27 activity. Last, antibodies generated against synthetic peptides derived from the HLA-B27.1 amino acid sequence were tested against the Yersinia component. Positive reactivity was found with antibodies generated against a peptide spanning residues 69-83 of the HLA-B27.1 protein. Since this resides in the segment responsible for the allotypic specificity of the antigen, these experiments establish the presence of molecular mimicry to a high degree of confidence.