DNA Methylation in the Hypothalamic Feeding Center and Obesity

Obesity rates have been increasing worldwide for decades, mainly due to environmental factors, such as diet, nutrition, and exercise. However, the molecular mechanisms through which environmental factors induce obesity remain unclear. Several mechanisms underlie the body's response to environmental factors, and one of the main mechanisms involves epigenetic modifications, such as DNA methylation. The pattern of DNA methylation is influenced by environmental factors, and altered DNA methylation patterns can affect gene expression profiles and phenotypes. DNA methylation may mediate the development of obesity caused by environmental factors. Similar to the factors governing obesity, DNA methylation is influenced by nutrients and metabolites. Notably, DNA methylation is associated with body size and weight programming. The DNA methylation levels of proopiomelanocortin (Pomc) and neuropeptide Y (Npy) in the hypothalamic feeding center, a key region controlling systemic energy balance, are affected by diet. Conditional knockout mouse studies of epigenetic enzymes have shown that DNA methylation in the hypothalamic feeding center plays an indispensable role in energy homeostasis. In this review, we discuss the role of DNA methylation in the hypothalamic feeding center as a potential mechanism underlying the development of obesity induced by environmental factors.

Measurement of the Positive Muon Anomalous Magnetic Moment to 0.46 ppm

We present the first results of the Fermilab National Accelerator Laboratory (FNAL) Muon g-2 Experiment for the positive muon magnetic anomaly a_{μ}≡(g_{μ}-2)/2. The anomaly is determined from the precision measurements of two angular frequencies. Intensity variation of high-energy positrons from muon decays directly encodes the difference frequency ω_{a} between the spin-precession and cyclotron frequencies for polarized muons in a magnetic storage ring. The storage ring magnetic field is measured using nuclear magnetic resonance probes calibrated in terms of the equivalent proton spin precession frequency ω[over ˜]_{p}^{'} in a spherical water sample at 34.7 °C. The ratio ω_{a}/ω[over ˜]_{p}^{'}, together with known fundamental constants, determines a_{μ}(FNAL)=116 592 040(54)×10^{-11} (0.46 ppm). The result is 3.3 standard deviations greater than the standard model prediction and is in excellent agreement with the previous Brookhaven National Laboratory (BNL) E821 measurement. After combination with previous measurements of both μ^{+} and μ^{-}, the new experimental average of a_{μ}(Exp)=116 592 061(41)×10^{-11} (0.35 ppm) increases the tension between experiment and theory to 4.2 standard deviations.

Efficacy of porcine placental extract on wrinkle widths below the eye in climacteric women

OBJECTIVE

Injections of human placental extract, which is known to play a role in skin regulation, have long been used for the treatment of skin wrinkles and non-healing wounds. Porcine placental extract (PPE), an oral supplement, was recently developed for this purpose. The aim of this study was to assess whether PPE has a positive effect on the improvement of fine wrinkles below the eye in climacteric women.

METHODS

We first non-invasively measured wrinkle widths with a skin analyzer in a cross-section of 185 healthy adult Japanese women. Next, 44 climacteric women with mild or few climacteric symptoms were enrolled into an open-label, randomized, controlled study of the effect of PPE on wrinkle widths. A retrospective comparison of wrinkle widths in 123 climacteric women with climacteric symptoms with or without PPE treatment was also performed.

RESULTS

Wrinkle widths below the eye in women ≥ 30 years of age were significantly higher than in women 20-29 years of age. Treatment with three capsules of PPE per day was significantly (p < 0.05) effective in reducing wrinkle widths at 24 weeks compared with control subjects. Retrospective analysis showed that subjects treated with three (p < 0.05) and six (p < 0.01) capsules of PPE per day observed a significant reduction in wrinkle widths compared with untreated subjects.

CONCLUSION

Oral PPE treatment is a possible option for improving the appearance of fine wrinkles below the eye in climacteric women.

Efficacy of porcine placental extract on shoulder stiffness in climacteric women

OBJECTIVES

Some of the most common climacteric symptoms are somatic symptoms, such as muscle and joint pain, which cause limitations in performing daily tasks. This study aimed to assess whether oral porcine placental extract (PPE) affects patients with shoulder stiffness, one of the most common types of muscle-tendon stiffness, in climacteric women and postmenopausal women with hormone therapy (HT).

METHODS

Sixty-six climacteric women (33 each in the control and study groups) with shoulder stiffness and 54 postmenopausal women (27 each in the control and study groups) with HT-resistant shoulder stiffness were enrolled into this open-label, randomized, controlled study. The control subjects received Toki-shakuyaku-san (TJ23; 7.5 g/day, daily per os), an oral herbal remedy used to alleviate climacteric symptoms, and study subjects received PPE orally for 24 weeks in climacteric women and for 12 weeks in postmenopausal women with HT. Changes in the degree of shoulder stiffness were evaluated by the Visual Analog Scale (VAS).

RESULTS

Treatment with PPE was significantly effective in reducing the VAS score for shoulder stiffness during the study period compared with the control group in both climacteric and postmenopausal women with HT. The VAS score at the end of treatment was significantly reduced (p < 0.01 vs. baseline) by 76.4% for climacteric women and 64.8% for postmenopausal women with HT compared with baseline.

CONCLUSIONS

PPE is useful as an oral supplement for shoulder stiffness in climacteric women without HT or in postmenopausal women with HT-resistant, long-term shoulder stiffness.

Efficacy of porcine placental extract on climacteric symptoms in peri- and postmenopausal women

OBJECTIVES

Injections of human placental extract have long been used to treat menopausal symptoms. Recently, porcine placental extract (PPE), an oral supplement, has been developed for this purpose. The aim of this study was to assess whether PPE has an impact on climacteric symptoms in perimenopausal and postmenopausal women.

METHODS

Seventy-six women with climacteric symptoms were enrolled into this open-label, randomized, controlled study. The control group (n = 38) underwent 24 weeks of open treatment with Toki-shakuyaku-san (TJ23), an oral herbal remedy used to alleviate climacteric symptoms. The PPE group (n = 38) received three capsules of PPE/day orally for the initial 12 weeks and six capsules/day for the next 12 weeks. Climacteric symptoms were evaluated in both groups using the Simplified Menopausal Index (SMI) score, Zung's Self-Rating Depression Scale (ZSDS) and the Spielberger State-Trait Anxiety Inventory (STAI) before commencing treatment, after 12 weeks of treatment and on completion of treatment.

RESULTS

Treatment with PPE was significantly (p < 0.01) more effective in reducing the SMI, ZSDS and STAI measures at 12 and 24 weeks than TJ23 treatment alone. Treatment with PPE was also significantly effective (p < 0.01) in reducing the subscale scores of the SMI for items such as hot flushes, insomnia, irritability, depression, fatigue and joint pain. PPE treatment had no significant adverse effects.

CONCLUSION

Oral PPE treatment is another possible option for treating perimenopausal and postmenopausal women with climacteric symptoms.

Efficacy of porcine placental extracts with hormone therapy for postmenopausal women with knee pain

OBJECTIVES

Knee pain related to osteoarthritis increases with age and is more common in middle-aged women. Although hormone replacement therapy (HRT) improves knee pain, women unresponsive to HRT need an effective adjunctive therapy. The aim of this study was to assess whether oral porcine placental extracts (PPE) have an impact on patients with knee pain as an adjunctive therapy combined with HRT.

METHODS

Forty-eight postmenopausal women with knee pain receiving HRT were enrolled into this open-label, randomized, controlled study. Subjects were randomized into Group 1 (n= 24) or Group 2 (n=24). Subjects in Group 1 were given 3 months open treatment with calcium (260 mg/day) as adjunctive therapy combined with HRT. Group 2 received PPE (9 capsules/day) as adjunctive therapy combined with HRT. Changes in the degree of knee pain were evaluated by the Visual Analog Scale (VAS).

RESULTS

Treatment with PPE was significantly effective in reducing the VAS score for knee pain at 4 weeks (p < 0.05), at 8 weeks (p< 0.01) and at 12 weeks (p<0.01), compared with the control group. Interestingly, the effects continued for 4 weeks after cessation of treatment in the PPE group (p< 0.01) compared with the control group. The PPE treatment had no significant adverse effects on blood biochemical and metabolic profiles, especially related to the risk factors for cardiovascular disease.

CONCLUSION

PPE is a possible option as an adjunctive oral supplement in the case of HRT-resistant, long-lasting knee pain.

Paxillin: application of immunohistochemistry to the diagnosis of chromophobe renal cell carcinoma and oncocytoma

Paxillin is a cytoskeletal protein that was recently identified as a component of focal adhesions and links between F-actin and integrin. In this study, 91 renal tumors--65 conventional renal cell carcinomas (RCCs), 14 papillary RCCs, 6 chromophobe RCCs, 4 collecting duct carcinomas, 2 oncocytomas--were investigated for the immunohistochemical expression of paxillin. In a normal kidney, paxillin was predominantly expressed in the cytoplasm of distal tubules, loops of Henle, collecting ducts, and vascular smooth muscle cells. In all of the chromophobe RCCs and oncocytomas, strong expression of paxillin was observed in the tumor cytoplasm. In contrast to these tumors, conventional RCCs, papillary RCCs, and collecting duct carcinomas showed negative reactions for paxillin except for one case in each subgroup with weak reactivity. An immunoblot analysis confirmed the presence of paxillin in healthy kidney, chromophobe RCC, and oncocytoma. These data suggest that paxillin possibly plays a role in signal transductions as a focal adhesion intervening between tumor cells and the extracellular matrix in renal tumors with collecting duct phenotypes such as chromophobe RCCs and oncocytomas, but not in conventional RCCs. In addition, paxillin may be an available marker in distinguishing chromophobe RCCs from conventional or papillary RCCs.

Treatment with low-dose interferon-alpha restores the balance between matrix metalloproteinase-9 and E-cadherin expression in human transitional cell carcinoma of the bladder

Tumor invasion and metastasis are regulated by the expression of genes such as E-cadherin, which regulates cell adhesion, and matrix metalloproteinase-9 (MMP-9), which alters the integrity of the extracellular matrix. Both up-regulation of MMP-9 and down-regulation of E-cadherin correlate with bladder cancer metastasis. The purpose of this study was first to determine whether an imbalance between MMP-9 and E-cadherin expression correlates with metastasis from human transitional cell carcinoma (TCC) of the bladder after therapy with neoadjuvant chemotherapy and radical cystectomy and then to determine whether treatment of human TCC xenografts growing in nude mice with interferon (IFN)-alpha would restore this balance, thereby limiting tumor invasion and metastasis. We used in situ hybridization to evaluate the expression of several metastasis-related genes, including MMP-9 and E-cadherin, in paraffin-embedded biopsy specimens from 55 patients with muscle-invasive TCC treated with neoadjuvant methotrexate, vinblastine, doxorubicin, and cisplatin chemotherapy and radical cystectomy. By multivariate analysis, an MMP-9:E-cadherin ratio of >1.8 was an independent prognostic factor for disease progression. In vitro incubation of an IFN-resistant, highly metastatic human TCC cell line, 253J B-V(R) with noncytostatic concentrations of IFN-alpha down-regulated the activity of MMP-9, up-regulated E-cadherin, and inhibited in vitro invasion. 253J B-V(R) cells were implanted into the bladders of athymic nude mice. Systemic therapy with IFN-alpha (10,000 units s.c. daily) decreased the expression of MMP-9, increased expression of E-cadherin, reduced tumor volume, and inhibited metastasis. The MMP-9:E-cadherin ratio was 4.5 in untreated controls and 1.1 after IFN-alpha treatment. Moreover, systemic low-dose daily IFN-alpha potentiated the efficacy of paclitaxel. These studies indicate that in addition to its antiproliferative and antiangiogenic effects, IFN-alpha limits tumor invasion by restoring the normal balance between MMP-9 and E-cadherin and enhances the activity of systemic chemotherapy.

The prognostic value of angiogenesis factor expression for predicting recurrence and metastasis of bladder cancer after neoadjuvant chemotherapy and radical cystectomy

To determine the prognostic value of angiogenesis factor expression for patients with muscle-invasive transitional cell carcinoma (TCC) of the bladder treated with neoadjuvant methotrexate, vinblastine, doxorubicin, and cisplatin (M-VAC) chemotherapy and radical cystectomy, we evaluated the expression of basic fibroblast growth factor (bFGF), vascular endothelial growth factor (VEGF), and interleukin 8 (IL-8) by in situ hybridization, and we determined microvessel density (MVD) by immunohistochemistry. These factors were evaluated in 55 biopsy specimens prior to therapy and in the cystectomy specimens of 51 patients after completion of therapy. By univariate analysis, VEGF expression and MVD in the biopsy specimens were significant predictors of disease recurrence. By multivariate analysis, only VEGF expression was an independent prognostic factor. Pathological stage, bFGF expression, and MVD in the cystectomy specimens after therapy were all independent prognostic factors for disease recurrence. The results of this exploratory study indicate that the expression levels of VEGF and bFGF as indicated by in situ hybridization and MVD as indicated by immunohistochemistry identify patients with muscle-invasive TCC who are at high risk of developing metastasis after aggressive therapy with systemic M-VAC chemotherapy and radical cystectomy.

Vinculin: its possible use as a marker of normal collecting ducts and renal neoplasms with collecting duct system phenotype

Vinculin is a cytoskeletal protein associated with membrane actin-filament-attachment sites of cell-cell and cell-matrix adherens-type junctions. In this article, we examine the expression of vinculin to elucidate its role in human renal neoplasms. We reviewed surgically resected specimens and selected available tissue from 79 renal tumors in 78 patients. There were 55 men and 23 women. Their mean age was 61 years and the mean size of the renal tumors was 6.1 cm. All renal tumors were examined by immunohistochemistry using a monoclonal antibody against vinculin. Overall, 17 (21.5%) renal tumor samples reacted with vinculin. The positive ratio in various types of renal tumors was as follows: conventional-type (clear cell), 0/54; papillary-type, 5/12; chromophobe-type, 5/5; sarcomatoid-type, 3/4; collecting duct carcinoma, 3/3; and oncocytoma, 1/1. The positive rate of conventional-type renal cell carcinomas (RCCs) is significantly different from that of other renal tumors (P < .01). Normal kidney, conventional, and papillary-type RCCs exhibited positive signals in Western blot analysis. These results suggest that vinculin may serve as a useful marker of renal neoplasms with collecting duct system phenotype such as chromophobe-type RCC.

Numerical chromosomal changes in metastatic prostate cancer following anti-androgen therapy: fluorescence in situ hybridization analysis of 5 Japanese cases

We used fluorescence in situ hybridization with centromere-specific probes for chromosomes 7, 8, 10, and Y to determine the copy number of these chromosomes in metastatic prostate cancers of five Japanese cases. Freshly prepared samples were obtained from prostate needle biopsies at different phases of clinical treatment; pretreatment, 1 week, 4 weeks, 12 weeks, 24 weeks post-treatment (PT), and clinical relapse. Gain of chromosomes 7 and 8, as noted in pretreatment samples; however, in post-treatment specimens (four of five cases), a remarkable reduction in the number of cells with extra copies of these chromosomes was detected. This decrease in the number of cells with additional chromosome 7 and 8 signals was correlated with the clinicohistopathological findings until 4 weeks PT. Chromosomes Y and 10 did not show numerical aberrations before treatment or changes in cells with aneusomy after treatment in all five cases. Our results suggest that gains of chromosomes 7 and 8 correlate with high grade and stage, and that changes in the cell number with aneusomy of chromosomes 7 and 8 reflect the clinical effects of anti-androgen therapy at an early phase, which may also indicate the androgen dependency of prostate cancer cells.

Overexpression of c-met proto-oncogene associated with chromophilic renal cell carcinoma with papillary growth

Various genetic changes are involved in human renal cell carcinomas (RCCs). However, the molecular events related to other cytomorphological subtypes of RCC are not well known, apart from the relationship between the von Hippel-Lindau tumour suppressor gene and clear cell subtype RCC. We examined the overexpression of several growth factor receptors immunohistochemically and analyzed their relationship to the cytomorphological characters in 120 cases of RCCs. These receptors included c-met proto-oncogene product (c-MET), epidermal growth factor receptor (EGFR) and transforming growth factor beta receptor II (TGFbetaR). The overexpression of c-MET was detected in all cases (20/20) of the tubulo-papillary growth type and 78.3% (18/23) of chromophilic cell subtype, resulting in a very significant associations between c-MET overexpression and tubulo-papillary growth RCCs (P<0.0001), c-MET and chromophilic subtype RCCs (P<0.0001), and c-MET and EGFR (P<0.0001). EGFR overexpression was significantly associated with the compact growth RCCs (49/89, P<0.0001), clear cell subtype RCCs (P<0.005) and the overexpression of TGFbetaR (P<0.0001). These results strongly suggest a close correlation between the overexpression of c-MET and development of the chromophilic subtype of RCC with papillary growth pattern. EGFR expression is closely related to the pathogenesis of the clear cell subtype of RCC with compact growth pattern. The overexpression of c-MET, EGFR, and TGFbetaR may have roles that are individually significant in the morphogenesis of RCC.

Determination of the prognostic significance of unscheduled cyclin A overexpression in patients with esophageal squamous cell carcinoma

The expression of cyclin A protein was retrospectively investigated in 124 patients with human esophageal squamous cell carcinoma with immunohistochemical techniques using antibody to cyclin A protein (BF683). Of 124 tumors, 49 (39.5%) exhibited positive staining in cancer cells with this antibody. Staining was observed predominantly but not exclusively in the nucleus. A significantly higher degree of association of immunoreactivity with this antibody was detected for advanced types of tumors (stages I, II, III, and IV) than for early tumors (stage 0; P < 0.05). Patients with cyclin A immunopositivity had a significantly poorer survival rate than did other patients (P < 0.01). These findings provide the first evidence for frequent and unscheduled overexpression of cyclin A protein in human esophageal cancer and suggest the possibility that alteration of cyclin A overexpression is associated with tumor progression and patient prognosis for esophageal cancers.

[Gamma Glutamyltransferase]

Gamma-Glutamyltransferase (GGT), formerly called gamma-glutamyltranspeptidase, is predominantly a membrane-bound enzyme. The estimation of enzyme activity in serum is useful in monitoring hepatobiliary complaints. The electrophoresis with surfactant (Triton X-100) developed by the authors demonstrates five distinct bands of enzyme activity in the serum from patients with hepatitis. These bands are called isoenzyme GGT1 to 5 from anode to cathode, respectively. Four isoenzymes GGT2 to 5, except GGT1 are demonstrated in normal adult serum. The affinity electrophoresis is more variable to identify the hepatoma associated isoenzyme, namely HA-GGT. Concanavalin A used in the method has no affinity with HA-GGT and this isoenzyme is separated from GGT2. The diagnostic sensitivity and specificity for the measurement of HA-GGT were 58% and 83%, respectively.

Test-strip method for measuring lactate in whole blood

We have developed a dry reagent strip system for measuring lactate in whole blood. The test strip contains lactate oxidase (no EC number assigned), horseradish peroxidase (EC 1.11.1.7), and N-ethyl-N-(2-hydroxy-3-sulfopropyl)-m-toluidine. The system is designed to measure with a reflectometer the color that developed in the test strip, although the lactate concentration can be estimated without the reflectometer. The between-run coefficients of variation for controls at three concentrations were 2.9-5.3%. The lactate concentrations in blood samples from healthy subjects before and after exercise correlated well (r = 0.97) with the results measured by the comparison method with the use of lactate oxidase. This dry reagent strip system provides a convenient and rapid test for measuring blood lactate in clinical and sports medicine.

Test-strip method for measuring lactate in whole blood

We have developed a dry reagent strip system for measuring lactate in whole blood. The test strip contains lactate oxidase (no EC number assigned), horseradish peroxidase (EC 1.11.1.7), and N-ethyl-N-(2-hydroxy-3-sulfopropyl)-m-toluidine. The system is designed to measure with a reflectometer the color that developed in the test strip, although the lactate concentration can be estimated without the reflectometer. The between-run coefficients of variation for controls at three concentrations were 2.9-5.3%. The lactate concentrations in blood samples from healthy subjects before and after exercise correlated well (r = 0.97) with the results measured by the comparison method with the use of lactate oxidase. This dry reagent strip system provides a convenient and rapid test for measuring blood lactate in clinical and sports medicine.

Plasma fructosamine assay in children with insulin-dependent diabetes mellitus

Plasma concentrations of fructosamine, an indicator of glycated plasma proteins, were measured in non-diabetic children and children with insulin-dependent diabetes mellitus (IDDM) to see if they also correlate with glycemic control in children as well as in adults. Non-diabetic children aged less than 4 yr had significantly lower plasma fructosamine than non-diabetic children aged 4 or more. Total plasma protein in these children was slightly lower or close to that of older children. There was no difference in fructosamine between non-diabetic children aged 4 or more and healthy adult subjects. Plasma fructosamine in children with IDDM was twofold that of age-matched controls. In children with IDDM, correlations between fructosamine and HbAI (r = 0.799) or HbAIc (r = 0.841) were high. The measurement of plasma fructosamine, which is practical in children because of the small sample volume needed and no influence of HbF, is useful in the management of children with IDDM.

Diltiazem and verapamil reduce the loss of adenine nucleotide metabolites from hypoxic hearts

The present study was undertaken to elucidate possible mechanisms for a protection of myocardial cells from hypoxia-induced derangements in cardiac function and metabolism by calcium antagonists. For this purpose, rabbit hearts were perfused for 20 min under hypoxic conditions in the presence of 312 ng/ml diltiazem or 125 ng/ml verapamil, and then for 45 min under reoxygenated conditions. Metabolic changes in the myocardium and the perfusate were examined throughout. Hypoxia induced a marked decline in myocardial high-energy phosphates and an immediate release of ATP metabolites, such as adenosine, inosine and hypoxanthine, from the perfused heart. These changes were effectively depressed by diltiazem and verapamil. Hypoxia and subsequent reoxygenation resulted in a release of creatine phosphokinase from the heart, which was completely inhibited by the treatment with either diltiazem or verapamil. Myocardial calcium contents were increased by 20 min-hypoxic perfusion. Both diltiazem and verapamil are capable of preventing hypoxia-induced increase in the transmembrane flux of cellular components, which may be beneficial for the preservation of substances necessary for the ATP regeneration after hypoxia and for the inhibition of calcium overload in cardiac cells.

Changes in serum enzyme activity after transcatheter arterial embolization for hepatic neoplasm

We assayed serum levels of certain enzymes and tumor markers in patients after transcatheter arterial embolization (TAE) to evaluate the effectiveness of this treatment. Twenty patients had hepatocellular carcinoma and two patients had metastases to the liver from colon cancer. Assays were first done immediately after TAE and were continued for the next 12 days. Glutamic oxaloacetic transaminase (GOT; EC 2.6.1.1, L-aspartate:2-oxoglutarate aminotransferase), glutamic pyruvic transaminase (GPT; EC 2.6.1.2, L-alanine:2-oxoglutarate aminotransferase), and lactate dehydrogenase (EC 1.1.1.27; (S)-lactate:NAD+ oxidoreductase) peaked 24 to 48 h after TAE and returned to the base lines in 7 to 10 days. Mitochondrial GOT (mGOT) and glutamate dehydrogenase (GLDH; EC 1.4.1.2, L-glutamate:NAD+ oxidoreductase) also peaked at the same time after TAE. alpha-Fetoprotein peaked 2 h after TAE and decreased to half of the baseline on day 7. Carcinoembryonic antigen peaked at 24 h and fell at 48 h only in the patients with colon cancer. The total amount of cytosolic GOT, GPT, mGOT, and GLDH released was correlated to the volume of the necrotic mass estimated by computed tomography scans. The correlation coefficients for mGOT and GLDH were r = 0.919 and r = 0.939 (both p less than 0.001), respectively. Assays of mGOT and GLDH may be useful to estimate the volume of the necrotic mass of a hepatoma or metastatic carcinoma in the liver.

[Combination chemotherapy with cyclophosphamide, adriamycin, vincristine and prednisolone (VEPA) for non-Hodgkin's lymphoma]

Combination Chemotherapy with Adriamycin (VEPA) was applied to 16 patients with non-Hodgkin's lymphoma. The effects of VEPA therapy were compared with those of combination chemotherapy without Adriamycin (non-VEPA). Complete remission rate achieved with VEPA therapy was 37.5% while that with non-VEPA therapy was 27.6%. Histologically, the complete remission rate in cases of large-cell type treated with VEPA therapy was 40%, while that with non-VEPA therapy was 14.3%. No cases of stage IV showed complete remission, whereas the complete remission rate for cases of stage III was 37.5% for VEPA therapy, but 27.6% for non-VEPA therapy. From these results we concluded that VEPA therapy is more effective for non-Hodgkin's lymphoma, especially large-cell type, than non-VEPA therapy.

Salivary urea nitrogen as an index to renal function: a test-strip method

To investigate the feasibility of using salivary urea nitrogen as an index of renal glomerular filtration rate, we developed and applied a new analytical system consisting of a urease-containing test strip and an automatic reflectance spectrometer. The concentrations of urea nitrogen so determined correlate well (r = 0.93) with concentrations in serum. These preliminary data suggest that our method can be used routinely as a simple and reliable means of detecting abnormalities of renal function.

Salivary urea nitrogen as an index to renal function: a test-strip method

To investigate the feasibility of using salivary urea nitrogen as an index of renal glomerular filtration rate, we developed and applied a new analytical system consisting of a urease-containing test strip and an automatic reflectance spectrometer. The concentrations of urea nitrogen so determined correlate well (r = 0.93) with concentrations in serum. These preliminary data suggest that our method can be used routinely as a simple and reliable means of detecting abnormalities of renal function.