Paid Sick Leave and Sickness Benefits for employees’ economic and job security: A Scoping Review

 

In health emergencies, such as in the COVID-19 pandemic, the need to expand or introduce the Paid sick leave(PSL) and Sickness benefits(SB) increases. They are key components of the universal health coverage(UHC) and active labor market policies(ALMPs) that enable workers to take care of their health and guarantee return-to-work after recovery. This study examines effects those policies in achieving economic stability and job security of covered workers through a scoping review. Studies were selected using the search terms ‘paid sick leave', ‘sickness benefits', ‘paid sick day', and ‘earned sick leave’ in PubMed and Web of Science. Our search conducted on 6th April 2021 yielded 1,030 articles, of which 22 articles were included in the review. All articles were analyzed by the 4 sub-groups(employees, families, employers, and government) and we investigated indicators of socio-economic impacts on their lives. Articles are largely PSL(90.9%)-focused. PSL guarantees not only workers’ job security by securing employment agreement, but also their income security by promising part of wages enough to afford healthcare and living expenses during the medical treatment and recovery. Additionally, PSL attenuates employers’ financial risk, as it reduces presenteeism while increasing the return-to-work rate. Moreover, PSL and SB reduce the total healthcare and social security expenditures of the government. To sum up, PSL and SB guarantee health and labor rights by ensuring income and job security to employees while assuring financial stability to both employers, and the government. However, as the previous studies paid less attention on the equity of these impacts at the system levels, future research should more focus on the dimension.

Key messages

• PSL and SB guarantee health and labour rights by ensuring income and job security for employees, while assuring financial stability for both employers and the government.

• The previous studies that examined the effects of PSL and SB paid less attention on the equity of ensuring income and employment security, therefore future studies should focus more on this dimension.

The paid sick leave and sickness benefits for universal health coverage: a scoping review

Background

The countries with paid sick leave (PSL) and sickness benefits (SB) mostly provide the benefit coverage to specific categories of workers, which results in health inequalities among employees in COVID-19. The PSL and SB are key factors to achieve universal health coverage (UHC) in that they protect access to healthcare and improve population health. This study attempted to investigate whether the policies helped achieve the UHC when they were expanded.

Methods

This review followed the scoping review protocol of PRISMA-ScR. On April 6, 2021, we extracted the literature using the keywords ‘paid sick leave', ‘sickness benefits', ‘paid sick day', and ‘earned sick leave’ from PubMed and Web of Science and added two studies through hand-search. All articles were written in English. We did not limit the publication date.

Results

Forty-four selected studies were based in four single countries and the European Union. Most of the studies were published after 2010 (84.1%) and were conducted as cross-sectional (72.7%) studies. Not only workers who use PSL and SB but also children whose parents use PSL and SB increased their use of healthcare services and getting flu shots. Also, using PSL and SB decreased their unmet healthcare needs and emergency use. The various health status factors, such as infectious disease incidence, mortality, and presenteeism, also decreased.

Conclusions

The provisions of PSL and SB offer individual and public health benefits by allowing employees and their families to use healthcare services. Group of employees, we can expect similar public health impacts on newly covered groups, thus contributing to achieving the UHC. Since more than 90% of articles are published from the United States, future studies need to evaluate the outcomes of health effects in various European or Asian countries.

Key messages

• The provision of PSL and SB positively affects employees and their families by allowing them to use healthcare services.

• The expansion of PSL and SB contributes to the UHC by guaranteeing indirect medical costs that enable universal access to essential healthcare services.

Reducing clinical review burden for insertable cardiac monitors

Funding Acknowledgements

Type of funding sources: None.

Background

The insertable cardiac monitor (ICM) is an essential tool for the ambulatory diagnosis of arrhythmias. However, definitive diagnoses still rely on time-consuming, manual adjudication of electrograms (EGMs) transmitted to the patient care network. This EGM review burden may be minimized by automatically selecting a subset of EGMs for fast review without delaying the diagnosis.

Purpose

Develop EGM selection strategies to reduce the EGM review burden without delaying diagnoses.

Methods

A retrospective analysis of 1,000 randomly selected Abbott Confirm Rx devices with 90+ days of remote transmission history was performed, regardless of transmission frequency, and all EGMs were adjudicated as either true or false positive (TP, FP). Up to 3 EGMs per day per arrhythmia type were prioritized for review based on ventricular rate and episode duration, with rules specific to each arrhythmia type: atrial fibrillation (AF), tachycardia, bradycardia, and pause. The resulting reduction in EGM review burden and TP days (patient-days with at least 1 TP EGM), as well as any diagnostic delay from the first transmitted TP, were calculated relative to reviewing all transmitted EGMs.

Results

In this population and transmission period, at least one AF, tachycardia, bradycardia, and pause EGM was transmitted by 424, 343, 190, and 325 unique devices, respectively, with a total of 35,723, 12,239, 19,752, and 28,002 EGMs, and a total of 6,163, 1,572, 1,438, and 646 TP days. For these patients with ≥1 EGM, the median [IQR] EGM transmission rate was 2.6 [0.7, 11.6], 1.1 [0.4, 4.7], 2.1 [0.6, 10.7], and 3.4 [0.6, 29.9] EGMs/patient/month, respectively. The optimal EGM selection strategy reduced this EGM review burden by 43%, 67%, 76%, and 50%, while only missing 3.4%, 2.2%, 0.3%, and 0.2% of TP days, respectively. Ultimately, 97%, 99%, 99%, and 99% of devices with a TP AF, tachycardia, bradycardia, or pause EGM exhibited no diagnostic delay vs. reviewing all transmitted EGMs.

Conclusion

EGM prioritization rules for selecting up to 3 episodes/day significantly reduced EGM burden across all patients, not just "frequent fliers," with no delay-to-diagnosis in >97% of patients who exhibited a true arrhythmia. Implementing these rules on the patient care network may improve clinical workflow and ICM patient management. Abstract Figure.

A study on accumulator analysis for the valve performance evaluation system of nuclear power plants

To evaluate the valves used in the nuclear power plants are working properly under the required conditions, the performance and capacity test should be performed. In the test system, the accumulator was employed to control the large amount of high pressure and high temperature steam generated in the boiler precisely. In the accumulating process, the steam is often condensed. In order to prevent condensation, it is needed to install heaters and preheat the accumulator. However, if the size of the accumulator becomes large, the installation of the heater may not be easy. Therefore, when the test is conducted, the system was preheated by the latent heat generated from the phase change. Insufficient thermal insulation may cause temperature differences and it can cause mechanical problems in the accumulator structure. If insulation is sufficient, the temperature difference is indicated by the height. As the cooled condensate moves downwards, the condensate is discharged by the drain valve control and the temperature difference of the structure can be disappeared. The results of this paper can be applied to the conceptualization of equipment that uses latent heat and for the design of high-precision steam experimental devices or the design of high-capacity steam utilization systems.

Sex-specific effect of obesity on exercise capacity and diastolic function

Background

Obese women are overrepresented in heart failure with preserved ejection fraction (HFpEF). We sought to 1) characterize the sex-specific effect of obesity on exercise capacity and diastolic function and 2) identify the determinant of exercise intolerance and diastolic dysfunction in each sex.

Methods

A total of 736 healthy participants, who underwent comprehensive health check-ups, were included in this study. All individuals were divided into 4 groups according to sex and presence of obesity (BMI ≥23kg/m2).

Results

The exercise capacity (peak VO2) was greatly affected by sex, which was worse in women. In addition, exercise capacity significantly differed according to obesity in women (23.5±7.3 vs. 21.3±5.4ml/kg/min, p<0.05), whereas there was no such difference in men (28.2±7.8 vs. 28.0±6.6ml/kg/min, p>0.10). Overall, women had an elevated E/e' ratio. Even non-obese women had a similar E/e' ratio to obese men (8.2±1.8 vs. 8.4±2.1, p>0.10) and obese women exhibited the highest E/e' ratio over any other group (Fig 1). Among 5 parameters (aging, obesity, elevated blood pressure, elevated heart rate, and elevated fasting glucose), obesity was a significant determinant of exercise intolerance for women, but not for men (women, HR 1.87 [95% CI 1.12–3.11], p=0.016; men, HR 1.22 [95% CI 0.63–2.38], p=0.558). Furthermore, obesity confers a greater risk of diastolic dysfunction in women than men (women, HR 4.03 [95% CI 2.24–7.25], p<0.001; men, HR 2.82 [95% CI 1.37–5.79], p=0.005).

Conclusions

Women had a more deleterious effect on exercise capacity and diastolic function in response to obesity than men. These sex-specific effects might explain the female predominance of HFpEF, particularly for the obese phenotype.

Figure 1

Funding Acknowledgement

Type of funding source: None

668Principal component analysis can identify ventricular regions with highest variability in the arrhythmogenic substrate of ventricular tachycardia patients

Introduction

Left ventricle (LV) substrate can be characterized by imaging modalities providing physiological variables (tissue perfusion, ischemia, etc.) grouped in a complex dataset. Principal Component Analysis (PCA) can identify the dataset variables that best explain its variance. Variables linked to substrate arrhythmogenicity will lead PCA to identify LV regions most influenced by the variables on a LV 3D geometry.

Purpose

To evaluate whether regions identified by PCA correspond to regions targeted by physicians in a ventricular tachycardia (VT) ablation procedure.

Methods

Ischemic VT subjects underwent SPECT/CT perfusion imaging (rest and stress) prior to LV voltage mapping with the cardiac mapping system. Co-registration allowed projection of ablation sites onto SPECT/CT geometries. PCA retrospectively analyzed the following dataset: tissue perfusion (rest and stress), tissue ischemia and the local (1cm2 sub-regions) stress-rest difference for: 1) standard deviation (STD) and 2) skewness (Skew). PCA components (PCAc) explaining ≥85% of the total variance were plotted on the LV 3D geometry to display regions highly influenced by the dataset variables (see figure below).

Results

Ten subjects (9 males, 66 ± 8 years old, LVEF 37 ± 11%) underwent co-registration. In 7/10 subjects, tissue perfusion (in PCAc#1) and ischemia (in PCAc#2) were most influential on LV regions variance. Ischemia and low perfusion (≤40%) areas equaled 32 ± 19 % of the LV with 21 ± 23% of these areas highly involved in the arrhythmogenic substrate (≥75% of explained LV variance). The location of 63 ± 18% of ablation sites were <1 cm from areas explaining ≥50% of LV variance.

Conclusion

Preliminary results showed that PCA can synthesize the influence of different perfusion derived variables, like tissue perfusion and ischemia, used in SPECT/CT imaging of the LV. Further analysis is needed to confirm whether this could be used to select VT ablation targets.

Abstract Figure.

The prevalence of and factors related to calcium pyrophosphate dihydrate crystal deposition in the knee joint

OBJECTIVES

The purpose of this study was to reveal the accurate prevalence and related factors to the presence of calcium pyrophosphate dihydrate (CPPD) crystal deposition in cadaveric knee joints.

DESIGN

Controlled laboratory study.

METHODS

Six hundred and eight knees from 304 cadavers (332 male knees and 276 female knees, formalin fixed, Japanese anatomical specimens) were included in this study. The average age of the cadavers was 78.3 ± 10.7 years. Knees were macroscopically evaluated for the existence of CPPD, and the depth of cartilage degeneration of the femoro-tibial joint following the Outerbridge's classification. CPPD crystal was confirmed under Fourier transform infrared spectroscopy (FTIR) analysis using light microscopy. Statistical analysis was performed to reveal the correlation between the occurrence of CPPD deposition in the knee joint and gender, age, and the depth of cartilage degeneration of the femoro-tibial joint.

RESULTS

The prevalence of grossly visible CPPD crystal was 13% (79 knees). In all of these knees, CPPD crystal was confirmed under FTIR analysis. Statistical analysis showed significant correlation between the occurrence of CPPD deposition and gender (P < 0.001), and depth of cartilage degeneration in the femoro-tibial joint (P < 0.001). In the cartilage degeneration positive knees (Over grade 3 in Outerbridge's classification), average age of CPPD deposition knee was significantly higher than CPPD negative knees.

CONCLUSIONS

In this study, the prevalence of CPPD deposition disease was evaluated in a relatively large sample size of cadaveric knees. The prevalence of CPPD deposition disease was 13%, and was significantly correlated with the subject's age, gender, and severity of cartilage degeneration in the femoro-tibial joint.

Numerical and Monte Carlo simulations of phenolic polymerizations catalyzed by peroxidase

Numerical and Monte Carlo simulations of horseradish peroxidase-catalyzed phenolic polymerizations have been performed. Kinetic constants for the simulations were fit to data from the oxidation and polymerization of bisphenol A. Simulations of peroxidase-catalyzed phenolic polymerization were run as a function of enzyme concentration and radical transfer and radical coupling rate constants. Predictions were performed with respect to conversion vs. time and number average molecular weight and polydispersity vs. conversion. It is shown that the enzymatic polymerization of phenols can be optimized with respect to high molecular weights by employing low enzyme concentrations and phenols with low radical coupling rate constants coupled with relatively high radical transfer rate constants. Such phenols may be identified by using linear free energy relationships that relate radical reactivity to electron donating/withdrawing potential of the phenolic substituent.

Prognostic impact of response to second-line chemotherapy on overall survival of patients with advanced gastric cancer

e15551

Background: It has been debated on whether tumor response to first-line chemotherapy (CT) would be reliable predictor for overall survival (OS) of cancer patients (pts). In case of advanced gastric cancer (AGC), many pts receive 2nd line CT after failure to 1st line treatment, so response to 2nd line CT as well as 1st line could affect OS. Methods: We retrieved clinical data of a total of 1,335 pts with AGC treated with palliative CT from January 2000 to December 2006 in National Cancer Center, Korea, including 757 pts who also received 2nd line CT. Responses to 1st and 2nd line CT were evaluable in 504 pts. Retrospective analysis was done to find correlation between objective tumor response to 1st and 2nd line CT and OS of the 504 pts, whom we divided into 4 groups: responders to both 1st and 2nd line CT (RR group); responders to 1st but not to 2nd line CT (RN group); responders to 2nd but not to 1st line CT (NR group); and nonresponders to both 1st and 2nd line CT (NN group). Results: Objective response rate of 1st and 2nd line CT was 41.7% and 12.3%, respectively. Responders to 1st line CT had a trend to respond to 2nd line CT (ORR of 2nd line CT in responders vs nonresponders to 1st line CT: 15.7% vs 9.9%, p = 0.049). 33/177/29/265 pts were assigned to each of RR/RN/NR/NN group, respectively. With median follow-up of 48.7 mo (range 23.2 - 93.7), median OS was 12.7 mo (95% CI 11.8–13.6). Baseline characteristics were balanced between 4 groups except higher hemoglobin and serum albumin level in RR group, younger median age in NN group, and fewer pts with poor performance status or poorly differentiated histology in NR group. Overall survival of RR, RN, NR, and NN group was 31.8 mo, 15.5 mo, 18.9 mo, and 9.2 mo, respectively (p<0.001). Multivariate analysis revealed relapsed disease after curative surgery, well-differentiated histology, absence of pulmonary metastasis, higher serum albumin level, lower serum bilirubin and alkaline phosphatase level, response to both of 1st line and 2nd line CT were reliable factors for favorable survival. Conclusions: Among the patients who received 2nd line chemotherapy for AGC, response to 2nd line CT was strongly associated with OS regardless of previous response to 1st line CT.

No significant financial relationships to disclose.

Characterization of the critical cycle length of a left atrial driver which causes right atrial fibrillatory conduction

A stable rhythm of very short cycle length (CL) in the left atrium (LA) can cause fibrillatory conduction, particularly in the right atrium (RA). Fast Fourier transform (FFT) analysis reliably identifies LA to RA conduction path(s) during atrial fibrillation (AF). We tested the hypotheses that FFT analysis of atrial electrograms (AEGs) during AF simulation will reliably identify the critical LA driver CL that causes RA fibrillatory conduction (i.e., the critical conduction breakdown CL) and that a longer critical conduction breakdown CL is found in atria of abnormal (sterile pericarditis) compared to normal dogs. We paced from Bachmann's bundle and the posterior-inferior LA at rapid rates to mimic an LA driver. During pacing, 4 sec of FFT analysis of 203 bipolar AEGs was performed and showed: 1) a single dominant frequency peak at the pacing CL in both atria when the atria followed the pacing in a 1:1 manner; 2) multiple and broad frequency peaks on the RA and parts of the LA at the conduction breakdown CL; and 3) the conduction breakdown CL is longer in pericarditis than normal dogs. FFT analysis allowed reliable detection of the critical CL of an LA driver that induces RA fibrillatory conduction.

Randomized phase II trial of neoadjuvant vs. adjuvant docetaxel plus cisplatin in patients with locally advanced gastric carcinoma: An interim analysis

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Background: The perioperative treatment strategy for locally advanced gastric cancer (LAGC) has not been clearly established. We conducted a randomized phase II study of neoadjuvant vs. adjuvant docetaxel/cisplatin (DC) chemotherapy in LAGC. Methods: LAGC was radiographically defined by CT and PET. Pts were randomized to receive neoadjuvant or adjuvant DC (docetaxel 36 mg/m2 + cisplatin 40 mg/m2 on D1, D8, q 3 wks X 3 cycles) according Japanese staging system (IIIa, IIIb, IV M-, and IV with a single M+ node). Results: All planned 88 pts in 44 per each arm were enrolled between Jan 2003 and Nov 2005. One pt was not eligible. The median age was 57 yrs vs. 58 yrs, PS 1 90.7% vs. 84.1%, and stage III/IV 72.1%/27.9% vs. 70.5%/29.5% in the neoadjuvant and adjuvant arm, respectively. Clinical response rate of 42 evaluable pts in neoadjuvant arm according to WHO criteria was 64.3% (95% CI 49.8–78.8%) with CR 2.4%, PR 61.9%, SD 31.0%, and PD 4.7%. There was no treatment related death. Comparison of G3/4 adverse events in neoadjuvant vs. adjuvant arm were; leukopenia 14.0% vs. 32.4% (p=0.04), neutropenia 37.2% vs. 62.2% (p=0.02), febrile neutropenia 0% vs. 2.7%, diarrhea 2.3% vs. 10.8%, stomatitis 2.3% vs. 8.1% (p=NS). There were no difference in the postoperative morbidity and the duration of hospital stay between both arms, but surgery was delayed in one pt who developed tuberculosis during neoadjuvant chemotherapy. Downstaging of the T stage could be obtained in 6 (14.3%) among 42 evaluable pts in neoadjuvant arm, according to EUS. Conclusions: Both neoadjuvant and adjuvant DC chemotherapy were relatively well tolerated in LAGC, with the lower incidence of G3/4 toxicities in neoadjuvant arm. Neoadjuvant DC showed a high response rate and a modest downstaging effect. (Supported by National Cancer Center Grant; Docetaxel was provided by Sanofi Aventis Korea)

[Table: see text]

No significant financial relationships to disclose.

Antioxidant effects of fructosyl arginine, a Maillard reaction product in aged garlic extract

The amino-carbonyl (Maillard) reaction of amino acids with sugars is a nonenzymatic browning reaction that takes place during the processing, cooking, and storage of foods. Maillard reaction products (MRPs) have been shown to possess interesting chemical and biological properties including antimutagenic and antioxidant activity. In this study, we determined the antioxidant effects of fructosyl arginine (Fru-Arg), a MRP in aged garlic extract. Low density lipoprotein (LDL) was incubated with Cu(2+) at 37 degrees C and 5% CO(2) for 24 hours, which resulted in an increase of thiobarbituric acid reactive substances (TBARS) indicating lipid peroxidation. Coincubation of Cu(2+) with Fru-Arg and LDL resulted in a significant inhibition of TBARS formation. Pulmonary artery endothelial cells (PAEC) were exposed to 0.1 mg/mL oxidized LDL (Ox-LDL) at 37 degrees C and 5% CO(2) for 24 hours. Lactate dehydrogenase (LDH) release, as an index of cell membrane damage, and TBARS were measured. Ox-LDL caused an increase of LDH release and TBARS formation. Pretreatment of PAEC with Fru-Arg inhibited these changes. Murine macrophages were incubated with Ox-LDL, and the release of peroxides was measured using a fluorometric assay. Ox-LDL caused an increased release of peroxides. Coincubation of macrophages with Fru-Arg and Ox-LDL inhibited the release of peroxides dose-dependently. In a cell free system, Fru-Arg was shown to scavenge hydrogen peroxide. These data suggest that Fru-Arg is a potent antioxidant, and thus may be useful for the prevention of atherosclerosis and other disorders associated with oxidative stress.

Importance of accurate geometry in the study of the total cavopulmonary connection: computational simulations and in vitro experiments

Previous in vitro studies have shown that total cavopulmonary connection (TCPC) models incorporating offset between the vena cavae are energetically more efficient than those without offsets. In this study, the impact of reducing simplifying assumptions, thereby producing more physiologic models, was investigated by computational fluid dynamics (CFD) and particle flow visualization experiments. Two models were constructed based on angiography measurements. The first model retained planar arrangement of all vessels involved in the TCPC but incorporated physiologic vessel diameters. The second model consisted of constant-diameter vessels with non-planar vascular features. CFD and in vitro experiments were used to study flow patterns and energy losses within each model. Energy losses were determined using three methods: theoretical control volume, simplified control volume, and velocity gradient based dissipation. Results were compared to a simplified model control. Energy loss in the model with physiologically more accurate vessel diameters was 150% greater than the simplified model. The model with nonplanar features produced an asymmetric flow field with energy losses approximately 10% higher than simplified model losses. With the velocity gradient based dissipation technique, the map of energy dissipation was plotted revealing that most of the energy was dissipated near the pulmonary artery walls.

Reversal of established autoimmune diabetes by restoration of endogenous beta cell function

In NOD (nonobese diabetic) mice, a model of autoimmune diabetes, various immunomodulatory interventions prevent progression to diabetes. However, after hyperglycemia is established, such interventions rarely alter the course of disease or allow sustained engraftment of islet transplants. A proteasome defect in lymphoid cells of NOD mice impairs the presentation of self antigens and increases the susceptibility of these cells to TNF-alpha-induced apoptosis. Here, we examine the hypothesis that induction of TNF-alpha expression combined with reeducation of newly emerging T cells with self antigens can interrupt autoimmunity. Hyperglycemic NOD mice were treated with CFA to induce TNF-alpha expression and were exposed to functional complexes of MHC class I molecules and antigenic peptides either by repeated injection of MHC class I matched splenocytes or by transplantation of islets from nonautoimmune donors. Hyperglycemia was controlled in animals injected with splenocytes by administration of insulin or, more effectively, by implantation of encapsulated islets. These interventions reversed the established beta cell-directed autoimmunity and restored endogenous pancreatic islet function to such an extent that normoglycemia was maintained in up to 75% of animals after discontinuation of treatment and removal of islet transplants. A therapy aimed at the selective elimination of autoreactive cells and the reeducation of T cells, when combined with control of glycemia, is thus able to effect an apparent cure of established type 1 diabetes in the NOD mouse.

Progesterone together with estrogen attenuates homologous upregulation of gonadotropin-releasing hormone receptor mRNA in primary cultured rat pituitary cells

In a previous study, we clearly demonstrated that an application of gonadotropin-releasing hormone (GnRH) to cultured rat pituitary cells increased the expression of GnRH receptor (GnRH-R) mRNA through transcriptional activation of GnRH-R gene rather than suppression of the turnover rate of GnRH-R mRNA. Along with GnRH, gonadal steroids seem to be an important regulator for GnRH-R expression in the pituitary gland. Recent in vivo studies reported that an application of gonadal steroids to gonadectomized animals modulated GnRH-R mRNA expression in the pituitary gland. However, it has not been clearly understood whether steroids may act directly at the pituitary or indirectly via modulation of hypothalamic GnRH release. Therefore, we assessed the effects of estrogen and progesterone on GnRH-R mRNA expression in primary cultured female rat pituitary cells. Neither estradiol nor progesterone modulates the basal expression of GnRH-R mRNA in primary cultured pituitary cells. When cultured pituitary cells were exposed to different doses of estradiol in combination with GnRH (0.2 nM), the GnRH-stimulated increment of GnRH-R mRNA expression was not significantly changed by estradiol at any given doses. However, when different doses of progesterone were added to primary cultured pituitary cells in combination with GnRH (0.2 nM), GnRH-induced increases in GnRH-R mRNA levels were reduced in a dose-related manner, showing a significant reduction at 100 nM progesterone. Furthermore, the addition of estradiol reinforced the suppressive effect of progesterone on the homologous upregulation of GnRH-R mRNA expression. Collectively, our results clearly demonstrated that progesterone directly attenuates the homologous upregulation of GnRH-R mRNA expression at the pituitary level, and that estradiol potentiates the effect of progesterone.

Identification of four novel mutations in classical Menkes disease and successful prenatal DNA diagnosis

Menkes disease is an X-linked recessive disorder of the copper metabolism and affected males suffer a systemic copper deficiency due to malabsorption and defective distribution of dietary copper. It is caused by a defect in the Menkes (ATP7A) gene, which encodes a transmembrane copper-transporting P-type ATPase. A variety of mutations were reported; however, only a few mutations were reported in Asian patients. We identified four novel mutations and one known mutation in five Korean patients. Arg646Ter in exon 8, a novel mutation transmitted from his carrier mother, was identified in one patient. Prenatal DNA diagnosis on an unaffected fetus in this carrier mother was successfully accomplished. An additional three novel mutations, Leu706Arg in exon 9, Gly1118Asp in exon 17, and Gly1255Arg in exon 19, were identified. Splicing mutation was not identified. Menkes disease in Korean patients appears to be caused by heterogeneous mutations with different spectrums from Caucasian patients.

Regulation of gonadotropin releasing hormone receptor mRNA expression in cultured rat granulosa cells

The homologous regulation of pituitary Gonadotropin Releasing Hormone Receptor (GnRH-R) mRNA expression by GnRH has been well demonstrated. However, the regulation of the ovarian GnRH-R is poorly understood. The present study was performed to demonstrate the presence of GnRH transcripts in addition to GnRH-R mRNA and the regulation of GnRH-R mRNA expression in the granulosa cells isolated from small antral follicles. The GnRH and GnRH-R mRNA levels were determined by a competitive reverse transcription-polymerase chain reaction (RT-PCR). The granulosa cells were obtained from immature rats implanted with diethylstilbestrol for 3 days. When GnRH transcript expression was examined in isolated granulosa cells by RT-PCR, the PCR products showed two bands. The larger band contained intronic sequences and the smaller band was a fully processed GnRH gene transcript identical to hypothalamic GnRH. This suggests that authentic GnRH gene transcripts are expressed in ovarian granulosa cells and may act on the granulosa cells in a paracrine or autocrine manner. Since GnRH action in the granulosa cells is mediated by specific GnRH-R, it is of interest to examine whether GnRH-R is synthesized in the granulosa cells. When the granulosa cells were cultured in media only, GnRH-R mRNA levels increased abruptly within 3 h and gradually decreased thereafter during the 24 h culture period. However, GnRH itself did not alter the GnRH-R mRNA expression levels in cultured granulosa cells. Interestingly, treatment with FSH decreased the GnRH-R mRNA levels in a dose-dependent manner. A time-course analysis revealed that the GnRH-R mRNA levels were significantly lower up to 9 h after FSH treatment, and returned to the basal level between 12 h-24 h. Activation of adenylate cyclase with forskolin also decreased the GnRH-R mRNA levels. It is therefore concluded that in the granulosa cells of the small antral follicles GnRH-R mRNA expression was not homologously regulated by GnRH, while FSH may negatively regulate GnRH-R mRNA expression in the granulosa cells possibly through a cAMP-protein kinase A pathway.

N alpha-(1-deoxy-D-fructos-1-yl)-L-arginine, an antioxidant compound identified in aged garlic extract

Aged garlic extract (AGE) has been shown to have antioxidant activity. The organosulfur compounds, S-allyl-L-cysteine and S-allylmercapto-L-cysteine, are responsible, at least in part, for the antioxidant activity of AGE. To identify major active components, we fractionated AGE, using hydrogen peroxide scavenging activity as an antioxidative index. Strong activity in the amino acid fraction was found and the major active compound was identified as N alpha-(1-deoxy-D-fructos-1-yl)-L-arginine (Fru-Arg). Antioxidant activity of Fru-Arg was comparable to that of ascorbic acid, scavenging hydrogen peroxide completely at 50 micromol/L and 37% at 10 micromol/L. Quantitative analysis using the established HPLC system revealed that AGE contained 2.1-2.4 mmol/L of Fru-Arg, but none was detected in either raw or heated garlic juice. Furthermore, it was shown that a minimum of 4 mo aging incubation was required for Fru-Arg to be generated. These findings indicate that the aging process is critical for the production of the antioxidant compound, Fru-Arg. These results may explain some of the variation in benefits among different commercially available garlic preparations.

Correlation between genotype and phenotype in Korean patients with spinal muscular atrophy

The goal of this study was to define the correlation between genotype and phenotype in Korean patients with spinal muscular atrophy (SMA). The SMA can be classified into three groups based on the age of onset and the clinical course. The candidate genes, survival motor neuron (SMN) gene, neuronal apoptosis inhibitory protein (NAIP) gene, and p44 gene were mapped and duplicated with telomeric and centromeric. The loss of the telomeric SMN occurs by a different mechanism. That is the deletion or conversion of telomeric SMN to centromeric SMN, in which case the conversion could produce a mild phenotype and deletion could produce a severe one. It has been known that there may be a balance between the numbers of copies expressed by the centromeric and telomeric SMN genes. In our study, ten patients with type I SMA and two type II patients were identified by their clinical findings and DNA studies. The major deletion of SMA candidate genes, deletion of the SMN gene, NAIP gene, and p44 gene were identified in six patients with type I SMA, while the rest of type I and all the type II patients showed the deletion of the SMN gene only. Allele numbers of the C212 marker were compared in patients and normal controls in order to find the correlation between the copy numbers and the clinical severity. The result was that type I patients had 2-5 alleles and the normal controls had 4-6. This suggests that the deletion is a major determining factor in the clinical phenotype. However, two type I patients with telomeric NAIP gene deletion notably had 4-5 alleles, as in the normal controls. This result implies that the correlation between the copy numbers and the severity is uncertain as opposed to the previous hypothesis. One type I patient showed the conversion of the centromeric SMN gene to the telomeric, which supports the conclusion that gene conversion is an important molecular mechanism for SMA. In the study of one hundred normal newborns, two physically normal newborns showed deletion of the centromeric SMN gene, suggesting frequent rearrangement in the locus.

Progesterone together with estrogen attenuates homologous upregulation of gonadotropin-releasing hormone receptor mRNA in primary cultured rat pituitary cells

In a previous study, we clearly demonstrated that an application of gonadotropin-releasing hormone (GnRH) to cultured rat pituitary cells increased the expression of GnRH receptor (GnRH-R) mRNA through transcriptional activation of GnRH-R gene rather than suppression of the turnover rate of GnRH-R mRNA. Along with GnRH, gonadal steroids seem to be an important regulator for GnRH-R expression in the pituitary gland. Recent in vivo studies reported that an application of gonadal steroids to gonadectomized animals modulated GnRH-R mRNA expression in the pituitary gland. However, it has not been clearly understood whether steroids may act directly at the pituitary or indirectly via modulation of hypothalamic GnRH release. Therefore, we assessed the effects of estrogen and progesterone on GnRH-R mRNA expression in primary cultured female rat pituitary cells. Neither estradiol nor progesterone modulates the basal expression of GnRH-R mRNA in primary cultured pituitary cells. When cultured pituitary cells were exposed to different doses of estradiol in combination with GnRH (0.2 nM), the GnRH-stimulated increment of GnRH-R mRNA expression was not significantly changed by estradiol at any given doses. However, when different doses of progesterone were added to primary cultured pituitary cells in combination with GnRH (0.2 nM), GnRH-induced increases in GnRH-R mRNA levels were reduced in a dose-related manner, showing a significant reduction at 100 nM progesterone. Furthermore, the addition of estradiol reinforced the suppressive effect of progesterone on the homologous upregulation of GnRH-R mRNA expression. Collectively, our results clearly demonstrated that progesterone directly attenuates the homologous upregulation of GnRH-R mRNA expression at the pituitary level, and that estradiol potentiates the effect of progesterone.

Homologous upregulation of gonadotropin-releasing hormone receptor mRNA occurs through transcriptional activation rather than modulation of mRNA stability

In a previous study, we showed that even continuous application of gonadotropin-releasing hormone (GnRH) could increase the steady-state levels of GnRH receptor (GnRH-R) mRNA if treated for a relatively short period (6 h). Therefore, in the present study we examined whether GnRH-induced increment of GnRH-R mRNA is owing to stabilization of the preexisting GnRH-R mRNA or new synthesis of GnRH-R mRNA or both. Initially, to examine the effect on new RNA synthesis, the transcription inhibitor, actinomycin D (2 microM), was added to primary cultured rat anterior pituitary cells. In the presence of transcription inhibitor, GnRH-induced augmentation of GnRH-R mRNA levels was completely abolished. This result indicates that homologous upregulation of GnRH-R mRNA expression occurs at least through new RNA synthesis of GnRH-R gene. We further assessed the effects of GnRH on the turnover rate of GnRH-R mRNA using actinomycin D (2 microM). The basal half-life of GnRH-R mRNA was estimated to be approx 21 h. The application of GnRH tended to slightly suppress the basal turnover rate of GnRH; however, there was no statistically significant difference, compared with the group treated with actinomycin D alone. Collectively, our results suggest that the homologous upregulation of GnRH-R mRNA may occur through transcriptional activation of GnRH-R gene rather than enhancement of GnRH-R mRNA stability, although we did not examine the transcription rate of GnRH-R gene.

Effects of immobilization stress on estrogen-induced surges of luteinizing hormone and prolactin in ovariectomized rats

Reproductive function has been known to be impaired by various kinds of physical and emotional stress, but the mechanism by which stress impairs the reproductive axis has not been clearly understood. In the present study, the effects of immobilization stress were studied on the surges of luteinizing hormone (LH) and prolactin (PRL) induced by 17beta-estradiol (E2) in ovariectomized rats. Two weeks after bilateral ovariectomy, animals were implanted with the capsule containing E2 or vehicle at 1000 h (designated as d 0). Immobilization was started at 1000 h and continued to 2100 h on d 2. Blood samples were collected according to the time schedule by a jugular vein catheter procedure. Immobilization stress inhibited basal release of LH and abolished E2-induced LH and PRL surges in ovariectomized (OVX) rats. Daily repeated immobilization (from 1200 h to 1800 h, 6 h/d) for 3 d also abolished LH and PRL surges when examined at 1800 h on d 2. Although daily repeated immobilization stress reduced E2-induced PRL mRNA levels, this stress failed to change LHbeta mRNA levels in the anterior pituitary as determined by Northern blot analysis. Gonadotropin-releasing hormone (GnRH) receptor mRNA levels in the anterior pituitary were lowered by immobilization stress in the OVX, E2-treated group. Dopamine D2 receptor mRNA levels in the anterior pituitary of OVX, E2-treated rats were significantly decreased at 1800 h, compared with those at 1000 h. However, immobilization prevented a decrease in dopamine D2 receptor mRNA levels at 1800 h. GnRH content was increased in the mediobasal hypothalamus by immobilization in the OVX, E2-treated group, suggesting that GnRH release was inhibited. Interestingly, GnRH mRNA levels in the preoptic area-anterior hypothalamic area were suppressed by immobilization stress in OVX, E2-treated rats when determined at 1800 h. Therefore, we concluded that immobilization stress blocks E2-induced LH surge possibly by inhibiting synthesis and release of GnRH at the hypothalamic level, and an increase of dopaminergic activity via D2 receptor at the pituitary level might be involved in the stress blockage of E2-induced PRL surge.

Homologous upregulation of GnRH receptor mRNA by continuous GnRH in cultured rat pituitary cells

The present study examined the effects of continuous treatment with gonadotropin-releasing hormone (GnRH) on GnRH receptor (GnRH-R) mRNA levels in dispersed cultures of rat pituitary cells. Pituitary GnRH-R mRNA levels were determined by competitive reverse transcriptase polymerase chain reaction. When pituitary cells were continuously exposed to a low dose of GnRH (0.2 nM), GnRH-R mRNA levels were transiently increased. The levels of GnRH-R mRNA were significantly increased up to 6 h and diminished to untreated levels by 24 h. Luteinizing hormone (LH) release was also increased significantly up to 12 h, maintaining similar levels in LH release thereafter. When GnRH antagonist ([D-pGlu1, D-Phe2, D-Trp3,6]-LH-RH) was added to the cultures together with GnRH (0.2 nM) for 6 h, the stimulatory effect of GnRH on GnRH-R mRNA levels and LH release was significantly diminished in a dose-related manner. In another experiment, pituitary cells were treated with various doses of GnRH (0.02-200 nM) for a relatively short (6 h) or a longer (24 h) period. When pituitary cells were exposed for 6 h, all doses of GnRH (0.02-200 nM) significantly increased GnRH-R mRNA levels in a dose-dependent manner. By contrast, continuous exposure to GnRH for 24 h was ineffective in changing pituitary GnRH-R mRNA levels at any given doses. These results indicate that the duration of GnRH treatment is critical for upregulation of GnRH-R mRNA by continuous GnRH. When pituitary cells were treated for 6 h with either a continuous mode of GnRH (0.2 nM) or an hourly pulsatile mode of GnRH (0.2 nM, 6 min/h), both treatments significantly augmented GnRH-R mRNA levels. Thus, the modes of GnRH application, if treated for a relatively short period, do not appear to make a significant difference in upregulation of GnRH-R mRNA levels. Collectively, our data provide strong evidence that continuous GnRH application is able to upregulate pituitary GnRH-R mRNA levels, if treated for a relatively short period (6 h).

High affinity hormone binding to the extracellular N-terminal exodomain of the follicle-stimulating hormone receptor is critically modulated by exoloop 3

The human follicle-stimulating hormone receptor (FSH-R) consists of two distinct domains of >330 amino acids, the N-terminal extracellular exodomain and membrane-associated endodomain. The exodomain alone binds hormone with high affinity, whereas the endodomain is the site of receptor activation. Coordination of these two domains is essential for successful hormone action but little is known about their functional and structural relationship. In this communication, we report that exoloop 3 of FSH-R constrains follicle-stimulating hormone binding to the exodomain. When the FSH-R exodomain was prepared by truncating its endodomain, the hormone binding affinity of the exodomain was slightly improved, compared with the wild type receptor. The binding affinity was further improved by >3-fold when the exodomain was attached to the membrane-associated domain of CD8. These results suggest that the FSH-R endodomain attenuates hormone binding at the exodomain. As a first step to test this hypothesis, the 11 amino acids except Ala589 of exoloop 3 were individually substituted with Ala. Ala substitution for Leu583 or Ile584 improved the hormone binding affinity by 4-6-fold while totally abolishing cAMP induction, indicating an inverse relationship. The Ala substitution for Lys580 or Pro582 had a similar trend but to a lesser extent. This significant improvement in the binding affinity suggests that the four residues at the N-terminal region of exoloop 3 interact with the exodomain and constrain the hormone binding in the wild type receptor. This effect is specific since substitutions for other than the 4 residues did not improve the hormone binding affinity. Computer modeling shows that the 4 residues can be positioned on one side of exoloop 3. This result and the apparent inverse relationship of hormone binding and cAMP induction suggest that these two essential functions may work against each other. Therefore, hormone binding might be compromised to preserve cAMP inducibility while maintaining a reasonably high, but below maximum, binding affinity.

Modulation of high affinity hormone binding. Human choriogonadotropin binding to the exodomain of the receptor is influenced by exoloop 2 of the receptor

The lutropin/choriogonadotropin receptor is a seven-transmembrane receptor and consists of two major domains of similar size, an extracellular exodomain and a membrane-associated endodomain which includes 3 exoloops. The uniquely large exodomain is responsible for high affinity hormone binding whereas receptor activation occurs at the endodomain. However, little is known about the relationship between the exodomain and endodomain. It was reported that hormone binding to the exodomain was improved when the endodomain was truncated. This result suggests that hormone binding to the exodomain was influenced by the endodomain. To test this hypothesis, amino acids of exoloop 2 were examined by Ala substitutions. The binding affinity was enhanced by some Ala substitutions but attenuated by others. These results indicate that exoloop 2 influences the hormone binding to the exodomain. Particularly, the high affinity hormone binding at the exodomain is constrained by a group of amino acids, Ser484, Asn485, Lys488, Ser490, and Ser499. Computer modeling suggests these residues may be positioned on one side of exoloop 2. It also influences the affinity for cAMP induction and the maximal cAMP production in distinct ways, in addition to its influence on the hormone binding affinity. The distinct ways of influencing these functions are sometimes in conflict and compromised to attain the maximal affinity for cAMP induction. As a result, the exodomain attains the maximal affinity for hormone binding when the endodomain is truncated and cAMP induction is disengaged.

Differential regulation of gonadotropin-releasing hormone (GnRH) receptor expression in the posterior mediobasal hypothalamus by steroid hormones: implication of GnRH neuronal activity

The present study is designed to evaluate the relationship between gonadotropin-releasing hormone (GnRH) and GnRH receptor (GnRHR) gene expression during the steroid-induced LH surge. One week after ovariectomy (OVX), a capsule containing 17beta-estradiol (E) or vehicle (V) was implanted into OVX rats, and 2 days later a single injection of progesterone (P) or V was administered s.c. at 10:00 h. Poly(A)-rich RNA samples were isolated from the micropunches of the preoptic area (POA) and the posterior mediobasal hypothalamus (pMBH) from both sides of individual brain slices. Using competitive reverse transcription-polymerase chain reaction (RT-PCR) procedures, three parameters (POA GnRH, pMBH GnRHR) and pituitary GnRHR mRNA levels were simultaneously determined in each individual animal. POA GnRH mRNA and pituitary GnRHR mRNA levels were decreased by treatment with E, but increased by a combination of E and P. In contrast, pMBH GnRHR mRNA levels were clearly augmented by treatment with E, and decreased by the combination of E and P. Temporal changes in such parameters were determined in OVX+E+V- and OVX+E+P-treated rats. P augmented POA GnRH mRNA levels at the time of the LH surge (17:00 h) and the increased GnRH mRNA levels were remained until 22:00 h, while E alone failed to alter POA GnRH mRNA levels. In the pMBH micropunch samples, P substantially decreased E-induced increase in GnRHR mRNA levels at 17:00 h and further lowered those until 22:00 h. Antisense oligonucleotides of GnRHR mRNA administered into the lateral ventricle of OVX+E-treated rats blocked the E-induced increase in pMBH GnRHR mRNA levels. The antisense oligonucleotides also prevented the LH surge as well as the increase in pituitary GnRHR mRNA levels in the OVX+E+P-treated group. However, administration of this antisense oligonucleotides failed to alter POA GnRH mRNA levels. In conclusion, the present study demonstrated that there is an inverse relationship between POA GnRH mRNA levels and pMBH GnRHR mRNA levels in response to E and/or P, and that the blockade of the E-induced increase in pMBH GnRHR mRNA levels effectively nullified the P-induced LH surge. These results indicate that pMBH GnRHR gene expression is involved in synchronizing the GnRH neuronal activity, which is crucial for the generation of the LH surge.