[Epidemiological characteristics of human respiratory syncytial virus (HRSV) among acute respiratory infection (ARI) cases in 16 provinces of China from 2009 to 2023]

Objective: To understand the epidemiological characteristics of human respiratory syncytial virus (HRSV) among acute respiratory infection (ARI) cases in 16 provinces of China from 2009 to 2023. Methods: The data of this study were collected from the ARI surveillance data from 16 provinces in China from 2009 to 2023, with a total of 28 278 ARI cases included in the study. The clinical specimens from ARI cases were screened for HRSV nucleic acid from 2009 to 2023, and differences in virus detection rates among cases of different age groups, regions, and months were analyzed. Results: A total of 28 278 ARI cases were enrolled from January 2009 to September 2023. The age of the cases ranged from<1 month to 112 years, and the age M (Q1, Q3) was 3 years (1 year, 9 years). Among them, 3 062 cases were positive for HRSV nucleic acid, with a total detection rate of 10.83%. From 2009 to 2019, the detection rate of HRSV was 9.33%, and the virus was mainly prevalent in winter and spring. During the Corona Virus Disease 2019 (COVID-19) pandemic, the detection rate of HRSV fluctuated between 6.32% and 18.67%. There was no traditional winter epidemic peak of HRSV from the end of 2022 to the beginning of 2023, and an anti-seasonal epidemic of HRSV occurred from April to May 2023. About 87.95% (2 693/3 062) of positive cases were children under 5 years old, and the difference in the detection rate of HRSV among different age groups was statistically significant (P<0.001), showing a decreasing trend of HRSV detection rate with the increase of age (P<0.001). Among them, the HRSV detection rate (25.69%) was highest in children under 6 months. Compared with 2009-2019, the ranking of HRSV detection rates in different age groups changed from high to low between 2020 and 2023, with the age M (Q1, Q3) of HRSV positive cases increasing from 1 year (6 months, 3 years) to 2 years (11 months, 3 years). Conclusion: Through 15 years of continuous HRSV surveillance analysis, children under 5 years old, especially infants under 6 months old, are the main high-risk population for HRSV infection. During the COVID-19 pandemic, the prevalence and patterns of HRSV in China have changed.

Comparison of the geriatric nutritional risk index and the prognostic nutritional index in determining survival outcome in patients with non-small cell lung cancer undergoing surgical resection: A cohort study

To assess the clinical feasibility of the geriatric nutritional risk index (GNRI) and prognostic nutritional index (PNI) as determinants of survival in patients with stage I to III non-small cell lung cancer (NSCLC). This retrospective study included patients with stage I to III NSCLC from all age groups. Hazard ratios (HRs) for overall survival (OS), cancer-specific survival (CSS), and relapse-free survival (RFS) were calculated using the Cox regression analysis. The concordance index (C-index) of the models was evaluated following the establishment of the prognostic models for survival. The median patient age was 69 years, and 64.6% of the patients were male. In total, 172 (65.4%) patients were classified as having stage I disease, 52 (19.8%) as stage II disease, and 39 (14.8%) as stage III disease. Using multivariate Cox regression analysis, the HRs of GNRI for OS, CSS, and RFS were 0.37 (P = .003), 0.47 (P = .041), and 0.38 (P < .001), respectively. However, the HRs of the PNI for survival outcomes were not statistically significant. Overall, age, sex, tumor-node-metastasis (TNM) stage, pleural invasion (PI), and GNRI were significant determinants of OS and constituted the OS model (concordance index [C-index], 0.824). In addition, age, TNM stage, PI, and GNRI were significant determinants of CSS and constituted the CSS model (C-index, 0.828). Finally, TNM stage, PI, lymphatic invasion, and GNRI were significant determinants of RFS and constituted the RFS model (C-index, 0.783). Our study showed that GNRI, but not PNI, was a predictor of OS, CSS, and RFS in patients with stage I-III NSCLC across all age groups. Excellent discriminant power was observed for OS, CSS, and RFS models.

Preoperative mean platelet volume is a prognostic biomarker for survival in patients with gastric cancer: A cohort study

This study aimed to evaluate the prognostic potential of mean platelet volume (MPV) in gastric cancer (GC) patients. Patients with stage I-III GC who underwent gastrectomy were enrolled in this study. Cox regression analysis was performed to evaluate the determinants of overall survival (OS) and disease-free survival (DFS). The discriminative capacity of the model was determined using the Harrell concordance index (C-index). The net benefit of the model was validated using decision curve analysis (DCA). Data from 401 patients were analyzed. Multivariate Cox regression analysis revealed that age, stage, serum albumin level (ALB), perineural invasion (PNI) and MPV were determinants of both OS and DFS. The MPV model consisted of 5 covariates (age, stage, ALB, PNI, and MPV level), and the baseline model constituted the same covariates as the MPV model, except for the MPV level. C-indices for OS and DFS were higher in the MPV model than in the baseline model. When the models were validated using DCA, the MPV model showed a greater net benefit than the baseline model for nearly all the threshold probabilities. Age, stage, ALB, PNI, and MPV are prognostic factors for OS and DFS. The discriminative capacities for OS and DFS in the MPV model were higher than those in the baseline model, thus implying the clinical significance of the MPV level as a determinant of survival in GC.

[Epidemiological characteristics of influenza and characteristics of hemagglutinin gene of B-Victoria strains in Hebei Province from 2018 to 2019]

Objective: To understand the epidemiological characteristics of influenza in Hebei Province from 2018 to 2019, and to analyze the characteristics and variation of hemagglutinin(HA) gene of influenza B-Victoria(BV) strains. Methods: Throat swab specimens of influenza-like cases within 3 days of fever were collected from 28 sentinel hospitals in Hebei province, meanwhile, The surveillance data was collected by the Chinese National Influenza Surveillance Network from April 2018 to March 2019, Throat swab specimens were collected from patients with influenza-like symptoms in sentinel hospitals, and tested by RT-PCR and virus isolation. 14 influenza B-Victoria strains from different regions were selected to sequence HA gene, Phylogenetic tree and the molecular characteristics were analyzed by DNASTAR 7.0 and Mega-X software. Results: From 2018 to 2019, A total of 99 266 cases of influenza-like illness (ILI) were detected from 4 689 103 cases by 28 influenza sentinel hospitals in Hebei Province, the visit percentage of ILI was 2.12%. During the period, 18 730 samples were detected, and 2 752(14.69%) samples were positive tested by RT-PCR, the peak was in the third week of 2019(44.92%), In the early stage of epidemic season, Influenza A(H1N1)pdm09 virus was the main type, while BV virus was the main type in the late stage. HA gene sequence analysis showed that the 14 BV viruses belonged to 162-164 amino acid deletion strains, the amino acid homology between HA sequences was 97.16%-100.00%, and 97.16%-98.95% compared with the vaccine strain B/Colorado/06/2017 recommended by WHO. Compared with the vaccine strains, 14 strains involved 11 amino acid site mutations. Conclusion: Influenza was prevalent in winter and spring in Hebei province from 2018 to 2019, Multiple mutations in antigenic sites of BV viruses might be related to the outbreaks.

Clinical Significance of Paraspinal Muscle Parameters as a prognostic factor for survival in Gastric Cancer Patients who underwent Curative Surgical Resection

Background: The quantitative and qualitative skeletal muscle parameters have been proposed to predict the outcome of patients with gastric cancer. However, the evidence for their association with long-term survival is still conflicting. This study aimed to investigate the effect of paraspinal muscle parameters on overall survival (OS) and disease-free survival (DFS) in patients with gastric cancer who underwent curative resection.

Methods: Patients with stages I or II gastric cancer who underwent curative resection between October 2006 and June 2016 were identified from electrical medical records. Paraspinal muscle area and attenuation were measured at the level of the third lumbar vertebra using computerized tomography images. For the analysis of OS and DFS, proportional hazards model was used, incorporating demographic, pathologic, laboratory, and radiologic variables.

Results: This study enrolled 296 patients (192 men and 104 women). In the multivariate proportional hazards model, total gastrectomy (hazard ratio [HR], 2.65; 95% Confidence interval [CI], 1.36-5.19; p = 0.0044), neutrophil-lymphocyte ratio (NLR) (HR, 1.27; 95% CI, 1.06-1.51; p = 0.0081), serum albumin level (HR, 0.16; 95% CI, 0.07-0.39; p < 0.0001), paraspinal muscle area adjusted for body surface area (PMA_BSA) (HR, 3.06; 95% CI, 1.65-5.67; p = 0.0004), and mean attenuation in paraspinal muscle (PMMA) (HR, 3.38; 95% CI, 1.75-6.53; p = 0.0003) were prognostic factors for OS. Similarly, total gastrectomy (HR, 2.11; 95% CI, 1.10-4.06; p = 0.0243), NLR (HR, 1.25; 95% CI, 1.06-1.48; p = 0.0071), serum albumin level (HR, 0.22; 95% CI, 0.10-0.51; p = 0.0035), PMA_BSA (HR, 2.42; 95% CI, 1.34-4.37; p = 0.0035), and PMMA (HR, 3.19; 95% CI, 1.71-5.93; p = 0.0003) were prognostic factors for DFS.

Conclusions: The pretreatment paraspinal muscle parameters such as PMA_BSA and PMMA along with total gastrectomy, NLR, and serum albumin level could predict OS and DFS in patients with stages I or II gastric cancer who underwent curative surgical resection. Because PMA_BSA and PMMA are newly characterized parameters in gastric cancer, the relationship with the survival of these parameters requires further validation in further studies before they are subjected to clinical applications.

[Mechanism relevant to hepatocellular carcinoma occurrence after negative conversion of viral DNA in treatment of chronic hepatitis B patients with nucleos(t)ide drugs]

Hepatocellular carcinoma (HCC) is a common malignant tumor in China, and most of the patients have a background of chronic HBV infection. Nucleos(t)ide drugs (NAs) are currently recommended by major guidelines as a first-line treatments for chronic hepatitis B. However, it is still clinically possible to observe that some patients who have acquired virological response (HBV DNA below the lower detection limit) after NAS treatment progress to HCC, and its mechanism of development is still unclear. In this review, the mechanism relevant to HCC progression in treatment of chronic hepatitis B patients with NAs is analyzed mainly from the aspects of gene integration and persistent inflammatory injury.

[Association of α-actinin-3 gene polymorphism and muscle strength of postmenopausal women]

Objective: To explore the association between α-actinin-3 (ACTN3) polymorphism and muscle strength in postmenopausal women. Methods: Five hundred and ninety-eight postmenopausal women with an average of (62.9±7.0) years old in Dongcheng District of Beijing were included. The ACTN3 polymorphism including rs540874, rs618838 and rs2229456 were genotyped by Sequenom Mass Array to explore their associations with muscle strength. One hundred and sixty-three of them were trained with regular Tai chi movement while 271 were administered with elemental calcium 600 mg/d combined with Vitamin D 800 U/d or calcitriol 0.25 μg/d for 2 years. Association between changes of muscle strength and ACTN3 polymorphism were analyzed. Results: The rs540874 genotypes were found to be significantly associated with chair stand test[GG (9.02±3.85) s vs GA (9.27±4.14) s vs AA (9.68±5.00) s, P=0.015]. Right grip strength in women with G allele were likely to be higher compared with A allele, but it was not statistically significant (P=0.056). Multiple linear regression showed that the chair stand test of AA genotype was statistically longer than that of GG and GA genotype (β=2.639, 95% CI: 1.632-4.646, P=0.010). The associations between rs618838, rs2229456 genotypes and muscle strength of both lower and upper limbs were not significant (all P>0.05). In addition, muscle strength of lower limbs of patients with rs540874 genotyped with G allele, rs618838 genotyped with C allele and rs2229456 genotyped with A allele increased significantly after enhanced exercise and vitamin D supplementation (all P<0.05). Conclusions: The rs540874 polymorphism of ACTN3 gene was associated with the muscle function of lower limb in postmenopausal women. The improvement of muscle strength after intervention were possibly correlated with rs540874, rs618838 and rs2229456 polymorphisms.

Efficacy and safety of thread embedding acupuncture combined with conventional acupuncture for chronic low back pain: A study protocol for a randomized, controlled, assessor-blinded, multicenter clinical trial

BACKGROUND

Back pain is one of the most common diseases, and many patients with recurrent pain seek alternative treatment strategies. Thread embedding acupuncture involves thread insertion at the acupuncture point for continuous physical and chemical stimulation. Although thread embedding is widely used in clinical practice, there is no sound evidence of its efficacy for chronic back pain. We describe the protocol for a randomized controlled trial for investigation of the efficacy and safety of thread embedding acupuncture combined with conventional acupuncture for chronic low back pain.

METHODS

This randomized, controlled, assessor-blinded, 2-armed, parallel, multicenter clinical trial will include 38 outpatients with chronic low back pain recruited from 4 traditional Korean Medicine hospitals. The patients will be randomly allocated to a treatment group (conventional acupuncture + thread embedding acupuncture) and a control group (only conventional acupuncture) in a 1:1 ratio. The treatment group patients will receive thread embedding acupuncture treatment at 10 acupuncture points (multifidus muscle, 4 points; spinal erector muscles, four points; lumbar quadrate muscle, 2 points) once a week for 8 weeks (8 sessions). In addition, all patients will receive conventional acupuncture treatment at 14 acupuncture points (GV3, EX-B5, and bilateral BL23, BL24, BL25, BL26, BL40, and BL60) twice a week for 8 weeks (16 sessions). The primary outcome will be the change in the visual analog scale score from visit 1 to visit 16, analyzed by independent t tests, in both groups. The groups will also be compared with regard to the clinical relevance (minimal clinically important difference), quality of life (3-level version of Euroqol-5D), disability level (Roland and Morris Disability Questionnaire), global assessment (patient global impression of change), and safety. Cost data for cost-benefit and cost-effectiveness analyses will be collected.

DISCUSSION

Our study results will provide evidence of the efficacy and safety of thread embedding acupuncture combined with conventional acupuncture for the management of chronic low back pain. Even though the assessors will be blinded, the patients will not be blinded to treatment because of the lack of a sham embedding acupuncture group; this is a limitation of our study.

TRIAL REGISTRATION

Clinical Research Information Service: KCT0002666.

MIR-150 promotes prostate cancer stem cell development via suppressing p27Kip1

OBJECTIVE

Our previous study found that high miR-150 expression was positively correlated with prostate tumor recurrence or metastasis. In this work, we investigated the expression of miR-150 in prostate cancer stem cells (CSCs) and explored its regulation over p27 in the development of CSCs.

MATERIALS AND METHODS

MiR-150 expression in CD144 or CD44 positive primary prostate cells and in DU145 cell line was measured. It regulation over CSCs was measured using tumor sphere assay and qRT-PCR analysis of CSC related Oct4, Nestin and Nanog genes. The direct binding between miR-150 and 3'UTR of p27 mRNA was verified using dual luciferase, qRT-PCR and western blot assay. The influence of miR-150-p27 axis on prostate CSC properties was further investigated.

RESULTS

Findings of this study found miR-150 expression was significantly upregulated in CD44+ or CD133+ subgroups of prostate cancer cells. MiR-150 could directly target 3'UTR of p27 and decrease its expression, through which it increased the number and volume of tumor sphere formed by DU145 cells, as well as the expression of CSC related Oct4, Nestin and Nanog genes.

CONCLUSIONS

Increased miR-150 expression might participate in the development and progression of human prostate CSC by suppressing p27. This supported our previous study which found miR-150 was positively correlated with prostate tumor recurrence or metastasis.

Viscosupplementation of synovial fluid with xanthan gum for treatment of osteoarthritis and its clearance kinetics in the rabbit knee joint

BACKGROUND

Injection of xanthan gum (XG) has been demonstrated to reduce the symptoms and progression of osteoarthritis (OA) in experimental models. Due to its high viscosity and stability, it may restore the rheological homeostasis of osteoarthritic synovial fluid (SF), and avoid numerous intra-articular injections.

OBJECTIVE

The present study investigated the effect of XG on the rheological properties of SF, and determined its residence time in the rabbit joint cavity.

METHODS

Rabbit knees were subject to intra-articular injection with XG or XG labeled with green fluorescence, and the SF was collected at different time. Rheological properties of SF with XG injected were compared with those with sodium hyaluronate injected. Resistance to oxidant damage was tested by adding H2O2 to the viscosupplement. Fluorescence intensity was measured for the SF with XG labeled with green fluorescence.

RESULTS

Results showed that XG could significantly improve the SF viscosity at 24, 96, 168 h, and increase the storage moduli (G') and loss moduli (G″) tested at frequency of 0.5 and 2.5 Hz. SF with XG injection exhibited a gel-like behavior at 24 h, in that G' exceed G″ over the entire oscillation frequency range. XG preparation had a high resistance to oxidant damage. Half-life of XG in the joint cavity was 35.9 h, with clearance obeying first-order kinetics.

CONCLUSIONS

Intra-articular injection of XG could improve the rheological properties of SF, and this effect could last for several days.

Antimicrobial activity of Ca(OH)2 containing pastes with Enterococcus faecalis in vitro

Sixty-eight standardized human root specimens were infected with Enterococcus faecalis for 3 wk after removal of the smear layer. After 3 wk of infection, the smear layer was reformed and in half of the specimens, the smear layer was again removed. Aqueous Ca(OH)2 paste and silicone oil based Ca(OH)2 paste were used as the test medications. The specimens were divided into four groups (i.e. (a) nonsmeared aqueous calcium hydroxide group, (b) nonsmeared silicon oil-based calcium hydroxide group, (c) smeared aqueous calcium hydroxide group, and (d) smeared silicon oil-based calcium hydroxide group. Medications were placed in the canals for 7 days. After removal of medications dentin chips were collected and incubated. The quantity of bacteria present was assessed. All calcium hydroxide pastes were effective in the elimination of bacteria in the dentinal tubules, except in the smeared group with silicone oil-based calcium hydroxide.

[Isolation and structure determination of xanthone glycosides of Anemarrhena asphodeloides]

Xilingzhimu, the rhizomes of Anemarrhena asphodeloides Bunge (Liliaceae), has been prescribed as antipyretic, anti-inflammatory, diuretic and hypoglycemic agents in Chinese traditional medicine. In this paper, two xanthone glycosides I and II, were isolated from Xilingzhimu by conventional method. The structures of I and II were identified on the basis of chemical reactions and UV, IR, 1HNMR, 13CNMR and DEPT. Compound I was identified as mangiferin and II is a new compound, named neomangiferin. Its structure is 7-O-beta-D-glucopyranosyl-mangiferin.

Elevation of intracellular Ca2+ concentration in rabbit nonpigmented ciliary epithelial cells by allicin

A previous study has shown that allicin produces changes in aqueous humor dynamics, and this study was conducted to examine possible cellular mechanisms. In rabbit nonpigmented ciliary epithelial cells, basal levels of [Ca2+]i were determined to be 164 +/- 34 nM. Allicin, a sulfhydryl-reactive agent, induced Ca2+ transients at 0.01 mM and at 0.2 mM, the Ca2+ transient peaked at 732 +/- 35 nM. Allicin-induced Ca2+ transients were prevented by pretreatment with dithiothreitol which did not affect the basal Ca2+ levels. Allicin had only a slight, insignificant, effect on L-type Ca2+ currents, and allicin-induced Ca2+ transients were also present under extracellular Ca(2+)-free conditions. These data suggest that intracellular Ca2+ stores are the most probable source of allicin's effect. Pretreatment of cells with ryanodine, an inhibitor of Ca(2+)-induced-Ca(2+)-release, inhibited allicin-induced Ca2+ transients, but the basal Ca2+ levels were unaffected by ryanodine. Thus, allicin-induced Ca2+ transients are most likely mediated through ryanodine-sensitive intracellular Ca2+ stores.

A procedure for quantitative determination of tris(2-carboxyethyl)phosphine, an odorless reducing agent more stable and effective than dithiothreitol

The concentration of tris(2-carboxyethyl)phosphine (TCEP) can be conveniently determined by measuring the amount of 2-nitro-5-thiobenzoate (NTB) formed after reaction with 5,5'-dithiobis(2-nitrobenzoic acid) (DTNB). This method utilizes the fact that TCEP reduces DTNB rapidly and stoichiometrically to generate two equivalents of NTB which, in its anionic form, has a molar extinction coefficient of 14,150 M-1 cm-1 at 412 nm. This method is sensitive enough to detect the concentration of TCEP in the micromolar range and has proven useful in monitoring the stability or oxidation of TCEP under various conditions. TCEP is not only very stable in acidic solutions, but unlike dithiothreitol (DTT) which readily oxidizes above pH 7.5, it is also highly stable in basic solutions. The rates of reduction of DTNB by TCEP and DTT are compared in the pH range 6-9. Below pH 8, TCEP is significantly more effective than DTT in reducing this disulfide. The rates of reduction of 2,2'-dithiodipyridine (2,2'-DTDP) by TCEP and DTT are compared in the pH range 1.5-8.5. Unlike DTT which is totally inactive at pH 1.5, TCEP is still capable of reducing 2,2'-DTDP effectively at this pH. Thus, if TCEP and thiols are simultaneously present, the concentration of TCEP can be selectively determined by using 2,2'-DTDP at very low pH.

Specific Detection and Properties of Enzyme Hydrolyzing Phosphonate Ester in Serum

An enzyme capable of hydrolyzing 4-methylumbelliferyl phenylphosphonate to 4-methylumbelliferone and phenylphosphonic acid has been detected in human serum. It has a Km value of 1.72 x 10(-4) mol/L, has an optimum pH of 8.8-9.1 in Tris buffer, and shows maximum activity at 60 degrees C (30 min). The enzymic activity can be inhibited by Na3PO4, EDTA, and cysteine. We saw no effect of CuSO4, adenosine, thymidine, NaN3, diethyl p-nitrophenyl phosphate, p-chloromercuribenzoate, isopropyl fluorophosphate, or eserine on the enzymic activity. The enzyme cannot hydrolyze substrates of phosphodiesterase I or alkaline phosphatase. The enzyme is considered a phosphonate esterase.

Specific detection and properties of enzyme hydrolyzing phosphonate ester in serum

An enzyme capable of hydrolyzing 4-methylumbelliferyl phenylphosphonate to 4-methylumbelliferone and phenylphosphonic acid has been detected in human serum. It has a Km value of 1.72 x 10(-4) mol/L, has an optimum pH of 8.8-9.1 in Tris buffer, and shows maximum activity at 60 degrees C (30 min). The enzymic activity can be inhibited by Na3PO4, EDTA, and cysteine. We saw no effect of CuSO4, adenosine, thymidine, NaN3, diethyl p-nitrophenyl phosphate, p-chloromercuribenzoate, isopropyl fluorophosphate, or eserine on the enzymic activity. The enzyme cannot hydrolyze substrates of phosphodiesterase I or alkaline phosphatase. The enzyme is considered a phosphonate esterase.

The synthesis of 5-iodoindoxyl-3-phenylphosphonate and its use in analysis of phosphodiesterase I

5-Iodoindoxyl-3-phenylphosphonate was prepared by using phenylphosphonic dichloride and 5-iodo-1-acetylindoxyl-3-ol. Its physical and chemical properties were studied. The results show that it can be used as an alternative substrate of snake venom phosphodiesterase I for assay of zymogram and in histochemistry.

Immobilization of chicken liver fructose 1,6-bisphosphatase on CNBr-activated Sepharose

Chicken liver fructose 1,6-bisphosphatase is readily immobilized on CNBr-activated Sepharose. The immobilization alters some enzymatic properties. They include broader pH activity curve, loss of activation by K+ or NH+4, increased resistance to inactivation by trypsin, decreased sensitivity to AMP inhibition, and loss of cooperative interaction among AMP-binding sites. The immobilized enzyme retains about 38% or 19% of the specific activity of the native enzyme when the activity is measured in the absence or presence of K+, respectively.

Synergistic effect of AMP and fructose 2,6-bisphosphate on the protection of fructose 1,6-bisphosphatase against inactivation by trypsin

The rate of inactivation of chicken liver fructose 1,6-bisphosphatase by trypsin is reduced if the digestive reaction is conducted in the presence of AMP or fructose 2,6-bisphosphate. The effects of these 2 compounds are synergistic. Although fructose 1,6-bisphosphate does not protect the enzyme against tryptic inactivation, it can enhance the effect of AMP. Selective modification of the AMP allosteric site of fructose 1,6-bisphosphatase with pyridoxal-P and NaBH4 renders the enzyme more resistant to tryptic inactivation, but the modified enzyme is no longer responsive to the protective effect of AMP.

Inactivation of yeast glucose-6-P dehydrogenase by aspirin

Glucose-6-P dehydrogenase is irreversibly inactivated by treatment with Na salts of aspirin. Kinetic data show that 1 molecule of aspirin reacts with each active unit when the enzyme is inactivated. The rate of inactivation is enhanced with increasing pH but is reduced in the presence of glucose-6-P or NADP+. Na salicylate fails to inactivate the enzyme.

Inhibition of liver fructose 1,6-bisphosphatase activity by Zn2+: reversal by imidazole pyruvate

Imidazole pyruvate was found to be a very potent natural chelating agent in reversing the inhibition of liver fructose 1,6-bisphosphatase activity by Zn2+. This metabolite may play a physiological role in gluconeogenesis.

A new method for measurement of cyclic AMP phosphodiesterase activity

The extreme sensitivity of chicken muscle fructose 1,6-bisphosphatase to inhibition by 5'-AMP has been utilized to develop a new method for the assay of cAMP phosphodiesterase activity. In this method, the substrate (cAMP) is first incubated with phosphodiesterase and the amount of 5'-AMP formed is then determined by measuring the degree of inhibition of fructose 1'6-bisphosphatase activity. The present method conveniently employs the spectrophotometric technique and is sensitive enough to detect the conversion of 50 pmol of cAMP to 5'-AMP in 1 ml of reaction mixture. This method is considered particularly valuable for those laboratories that are not equipped with facilities for measuring radioactivity.