Low Rate Group Research Articles

Hospital-level variation in racial disparities in low-risk nulliparous cesarean delivery rates

Nationally, rates of cesarean delivery are highest among Black patients compared with other racial/ethnic groups. These observed inequities are a relatively new phenomenon (in the 1980s, cesarean delivery rates among Black patients were lower than average), indicating an opportunity to narrow the gap. Cesarean delivery rates vary greatly among hospitals, masking racial disparities that are unseen when rates are reported in aggregate. This study aimed to explore reasons for the current large Black-White disparity in first-birth cesarean delivery rates by first examining the hospital-level variation in first-birth cesarean delivery rates among different racial/ethnic groups. We then identified hospitals that had low first-birth cesarean delivery rates among Black patients and compared them with hospitals with high rates. We sought to identify differences in facility or patient characteristics that could explain the racial disparity. A population cross-sectional study was performed on 1,267,493 California live births from 2018 through 2020 using birth certificate data linked with maternal patient discharge records. Annual nulliparous term singleton vertex cesarean delivery (first-birth) rates were calculated for the most common racial/ethnic groups statewide and for each hospital. Self-identified race/ethnicity categories as selected on the birth certificate were used. Relative risk and 95% confidence intervals for first-birth cesarean delivery comparing 2019 with 2015 were estimated using a log-binomial model for each racial/ethnic group. Patient and hospital characteristics were compared between hospitals with first-birth cesarean delivery rates <23.9% for Black patients and hospitals with rates ≥23.9% for Black patients. Hospitals with at least 30 nulliparous term singleton vertex Asian, Black, Hispanic, and White patients each were identified. Black patients had a very different distribution, with a significantly higher rate (28.4%) and wider standard deviation (7.1) and interquartile range (6.5) than other racial groups (P<.01). A total of 29 hospitals with a low first-birth cesarean delivery rate among Black patients were identified using the Healthy People 2020 target of 23.9% and compared with 106 hospitals with higher rates. The low-rate group had a cesarean delivery rate of 19.9%, as opposed to 30.7% in the higher-rate group. There were no significant differences between the groups in hospital characteristics (ownership, delivery volume, neonatal level of care, proportion of midwife deliveries) or patient characteristics (age, education, insurance, onset of prenatal care, body mass index, hypertension, diabetes mellitus). Among the 106 hospitals that did not meet the target for Black patients, 63 met it for White patients with a mean rate of 21.4%. In the same hospitals, the mean rate for Black patients was 29.5%. Among Black patients in the group that did not meet the 23.9% target, there were significantly higher rates of all cesarean delivery indications: labor dystocia, fetal concern (spontaneous labor), and no labor (eg, macrosomia), which are all indications with a high degree of subjectivity. The statewide cesarean delivery rate of Black patients is significantly higher and has substantially greater hospital variation compared with other racial or ethnic groups. The lack of difference in facility or patient characteristics between hospitals with low cesarean delivery rates among Black patients and those with high rates suggests that unconscious bias and structural racism potentially play important roles in creating these racial differences.

Risk Factors Affecting Muscle Mass Decline in Maintenance Hemodialysis Patients.

There is a high prevalence of sarcopenia in maintenance hemodialysis (MHD) patients, which is known to be associated with increased mortality. This study is aimed at analyzing the risk factors affecting muscle mass decline in MHD patients. This retrospective study included MHD patients who underwent two body composition assessments in October 2013 and November 2017. Depending on whether there was muscle loss or not, the patients were divided into a normal muscle mass (NMM) group and a muscle mass decline (MMD) group. According to the muscle mass decline rate, patients in the MMD group were further classified into a low-rate group and a high-rate group. Biochemical variables, serum vitamin concentrations, anthropometric data, SGA, muscle mass, handgrip, and daily steps were assessed. Risk factors for muscle mass decline were screened by multivariate logistic analysis and linear regression analysis. Of the 72 MHD patients included in this study, 33 were male and 39 were female with a mean age of 56.80 ± 10.86 years and a mean dialysis duration of 7.50 ± 5.20 years. Age (P = .014) and serum 25(OH)D (P = .040) were found to be associated with a higher risk of muscle mass decline after adjusting for gender, dialysis vintage, albumin, and hs-CRP (P = .040). Further analysis found that dialysis vintage (β = 0.285, P = .030), 25(OH)D (β = -0.351, P = .007), and log NT-proBNP (β = 0.312, P = .020) were risk factors associated with the muscle mass decline rate in MHD patients. Age and serum 25(OH)D were associated with a higher risk of muscle mass decline, while 25(OH)D, dialysis vintage, and NT-proBNP were associated with the muscle mass decline rate in MHD patients.

Prescription of Anticholinergic Drugs in Patients With Schizophrenia: Analysis of Antipsychotic Prescription Patterns and Hospital Characteristics.

In several clinical guidelines for schizophrenia, long-term use of anticholinergic drugs is not recommended. We investigated the characteristics of the use of anticholinergics in patients with schizophrenia by considering psychotropic prescription patterns and differences among hospitals. A cross-sectional, retrospective prescription survey at the time of discharge was conducted on 2027 patients with schizophrenia from 69 Japanese hospitals. We examined the relations among psychotropic drug prescriptions regarding anticholinergic prescription. We divided the hospitals into three groups—low rate group (LG), medium rate group (MG), and high rate group (HG)—according to their anticholinergic prescription rates, and analyzed the relationship between anticholinergic prescription rates and antipsychotic prescription. Anticholinergic drugs were prescribed to 618 patients (30.5%), and the prescription rates were significantly higher for high antipsychotic doses, antipsychotic polypharmacy, and first-generation antipsychotics (FGAs) use. The anticholinergic prescription rate varied considerably among hospitals, ranging from 0 to 66.7%, and it was significantly higher in patients with antipsychotic monotherapy, antipsychotic polypharmacy, and normal and high doses of antipsychotics in HG than in those LG and MG. The anticholinergics prescription rate in patients with second-generation antipsychotic monotherapy in HG was also significantly higher than in those LG and MG; however, the difference was no longer significant in patients with FGA monotherapy. Conclusively, in addition to high antipsychotic doses, antipsychotic polypharmacy, and FGA use, hospital characteristics influence the prescribing of anticholinergic drugs.

Kt/V reach rate is associated with clinical outcome in incident peritoneal dialysis patients

Background The urea clearance index (Kt/V) is an important index for predicting the clinical outcome of peritoneal dialysis (PD) patients, but it changes with time depending on the clinical condition. This study aimed to investigate the association between the Kt/V reach rate (defined as the percentage of Kt/V measurements that reached ≥ 1.70) and clinical outcome in incident PD patients. Methods In this retrospective cohort study, 210 patients were enrolled from the First Affiliated Hospital of Zhengzhou University from 1 January 2013 to 31 October 2019. The target Kt/V reach rate in the first year was applied as the predictor variable. Kaplan-Meier survival curves were drawn to evaluate differences in prognosis. The association between Kt/V reach rate and the composite clinical outcome (death or transfer to hemodialysis) was tested by Cox regression analysis. Results The dialysis adequacy group (Kt/V reach rate 3/3 times) and the dialysis intermittent adequacy group (1/3 or 2/3 times) had significantly better clinical outcomes than the dialysis inadequacy group (0/3 times). There was no difference in clinical outcome between the lower-rate group (reach rate 1/3 times) and the higher-rate group (2/3 times). Compared with the dialysis inadequacy group, the dialysis intermittent adequacy group and dialysis adequacy group had significantly lower risks of the composite outcome (HR 0.487, 95% CI 0.244–0.971, p = 0.041; HR 0.150, 95% CI 0.043–0.520, p = 0.003) in the fully adjusted analysis. Conclusion Higher Kt/V reach rates are associated with a better prognosis in incident PD patients.

Continuous genomic monitoring of multiple myeloma patients to identify patients of high risk for poor prognosis.

e20035 Background: Multiple myeloma (MM) is heterogeneous from symptoms, mechanisms of tumorigenesis and progression, to the treatment outcome. Besides age and tumor stage, prognostic models based on the genomic or transcriptomic profiles were developed to stratify patients into risk groups at diagnosis. Even though mutation burden at diagnosis is not associated with overall survival (OS), its change during the course of treatment, which might reflect the emergence of treatment resistant subclones, could provide insights about the MM evolution and hence associate with patient outcome. Methods: In this study, we developed a new parameter referred to as “tumor evolution rate” and investigated its association withclinical outcomes. The tumor evolution rate was measured as the rate of acquiring new somatic mutations among the sequential samples from the same patients. We utilized genomic data generated on 140 MM patients with two sequential samples from the MMRF CoMMpass database. The prognostic power of evolution rate was compared with other clinical parameters as well as gene expression-based markers. Results: There was significant heterogeneity in the evolution rate among MM patients (median, 0.114; 0.011 – 2.34 new mutations per day). The evolution rate was significantly associated with OS in a univariate Cox regression model (Wald test p = 5.0×10-7). When stratified into high, intermediate and low-rate groups, they had a median OS of 316, 743 and 998 days after the collection date of 2nd samples, respectively (logrank test p = 1.0×10-6). With age and ISS stage as covariates in the multivariate Cox regression model, the evolution rate remained significantly associated with OS (p = 6.3×10-6). The mutation burden itself at either sampling time was not associated with OS. For patients with two sequential samples collected less than 2 years apart (N =82), the evolution rate was significantly associated with OS (Wald test p = 2.0×10-6). However, for patients with two sequential samples collected more than 2 years apart, the evolution rate was not significantly associated with OS anymore, likely due to the inaccurate evolution rate estimates over long intervals. In addition, the patient stratified by the evolution rate shared some similarity with those stratified via a gene expression-based prognostic model (previously developed by us). The majority of patients in the low or intermediate risk group based on gene expression were in the low or intermediate evolution rate group. For patients with a high-risk prognosis (n = 21), 57% (12 out of 21) had tumors with a high evolution rate during treatment, suggesting alternative treatment options may be needed for this group of patients. Conclusions: Our study demonstrated that the tumor evolution rate as derived from continuous monitoring of tumor genomic changes provided extra prognostic information for identifying MM patients of poor prognosis after drug treatment.

Longitudinal Analysis of Fetal Ventricular Rate for Risk Stratification in Immune Congenital Heart Block

Objectives: To assess the perinatal risks of immune complete congenital heart block (iCCHB) based on the longitudinal analysis of fetal heart rate. Methods: Retrospective analysis of a cohort of grade III congenital heart block diagnosed in utero, in the absence of associated cardiac defect, with positive maternal serum antibodies. Longitudinal measurements of the fetal heart rate were used to estimate the average slope of ventricular rate as a function of gestational age. We then defined the following prognostic stratification based on longitudinal follow-up observations: the high-rate (HR) group included cases for which all prenatal ventricular rate measurements were above the age-specific mean of our population of iCCHB and the low-rate (LR) group included those with at least one observation below the mean during follow-up. The 2 groups were compared to analyze the potential relationship between prenatal ventricular rate and adverse neonatal outcome defined by in utero or perinatal death, neonatal heart rate <50 bpm, or hemodynamic failure requiring emergency pacing. Results: Forty-four cases were studied. Overall, the average heart rate significantly decreased during gestation from 65 bpm at 20 weeks to 55 bpm at 38 weeks. The HR and LR groups included 18 (41%) and 26 (59%) cases, respectively. Adverse perinatal outcome occurred in 1/18 (6%) and 22/26 (85%) cases in the HR and LR groups, respectively (p < 0.001). In the HR group, 33% of cases remained nonpaced at >6 months. The positive predictive values and negative predictive values for adverse perinatal outcome in the LR group were 85% (22/26) and 94% (17/18), respectively (100 and 80% <30 weeks and 88 and 78% at ≥30 weeks). Conclusions: The prognostic classification we developed based on longitudinal heart rate assessment may be used in the late 2nd or early 3rd trimester to identify iCCHB cases at high risk of adverse perinatal outcome. This prognostic stratification should help refine counseling and perinatal management earlier in pregnancy instead of waiting for late gestation or predelivery assessment.

Enthusiasm, Opinion Leaders, Comparative Advantage, and the Uptake Of Laparoscopic Resection For Colorectal Cancer Liver Metastases in Ontario, Canada: A Population-Based Cohort Study.

Numerous factors likely influence adoption of surgical innovations in large regions. We considered the role of comparative advantage, surgeon enthusiasm, and opinion leaders on uptake of minimally invasive liver resection (MILR) for colorectal cancer (CRC) metastases in Ontario. We used administrative data for patients undergoing liver resection for CRC metastases from years 2006-2015. Fourteen regions were divided into three groups based on overall rate of MILR for CRC metastases. Outcomes included postoperative complications, length of hospital stay (LOS), operative mortality, and 1-year survival. We evaluated uptake of MILR among groups and within groups between opinion leader and nonopinion leader surgeons. There were 2675 patients in the low-rate (n = 937), medium-rate (n = 919), and high-rate (n = 819) groups. In these same groups, the number of opinion leader surgeons was six, five, and six. Patient outcomes were similar among groups, except in the low-rate group LOS was 1day greater (7 vs. 6 and 6; p = 0.017). The rate of MILR for CRC metastases did not change significantly among opinion leaders in any group. This rate among nonopinion leader surgeons was steady and low in the low-rate group (1.7-8.0%, p = 0.80) and increased in the mid-rate group (2.4-31.8%, p = 0.0026) and in the high-rate group (7.7-40.9%, p < 0.001). Greater use of MILR was associated with a 1-day shorter LOS. Relative enthusiasm for MILR for CRC metastases among a small number of opinion leader surgeons likely facilitated or dampened uptake of this complex innovation.

Food availability before aestivation governs growth and winter reproductive potential in the capital breeding fish, Ammodytes japonicus.

Capital breeders develop gametes by using energy that was stored before the spawning season. Energy is allocated to growth and reproduction, and limited food availability affects the balance of energy allocation, especially in fish that mature within a year, such as western sand lance (Ammodytes japonicus). This species aestivates without feeding until winter spawning and utilize energy stores that were accumulated prior to aestivation for maturation and spawning. This study aimed to evaluate the growth, energy storage, maturation rate, and reproduction of A. japonicus in response to food availability before aestivation. We conducted laboratory experiments in which young-of-the-year A. japonicus were fed at rates of 4% and 1% of their body weight per day; assigned as high and low ration groups, respectively. In June, body length was found to be significantly larger in the high ration group than in the low ration group, but the somatic condition did not differ significantly between the groups. Maturation rates and average fecundities were 1.0 and 6297 in the high ration group and 0.8 and 2251 in the low ration group, respectively. These results indicate that food availability before aestivation strongly governs the reproductive potential of A. japonicus, and suggest the involvement of mechanisms in the inter-annual recruitment variation in sand lance species.

How the tracking of habitual rate influences speech perception.

Listeners are known to track statistical regularities in speech. Yet, which temporal cues are encoded is unclear. This study tested effects of talker-specific habitual speech rate and talker-independent average speech rate (heard over a longer period of time) on the perception of the temporal Dutch vowel contrast /ɑ/-/a:/. First, Experiment 1 replicated that slow local (surrounding) speech contexts induce fewer long /a:/ responses than faster contexts. Experiment 2 tested effects of long-term habitual speech rate. A high-rate group listened to ambiguous vowels embedded in "neutral" speech from Talker A, intermixed with fast speech from Talker B. A low-rate group listened to the same neutral speech from Talker A, and/but to Talker B speaking at a slow rate. Between-groups comparison of the neutral trials showed that the high-rate group demonstrated a lower proportion of /a:/ responses, indicating that Talker A's habitual speech rate sounded slower when B was faster. In Experiment 3, both talkers produced speech at both rates, removing the different habitual speech rates of Talkers A and B, while maintaining the average rates differing between groups. In Experiment 3, no global rate effect was observed. Taken together, the present experiments show that a talker's habitual rate is encoded relative to the habitual rate of another talker, carrying implications for episodic and constraint-based models of speech perception. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

Fluid Therapy Rate in Postrenal Azotemia Stabilization in Cats

Fluid therapy is the most important component involved in the stabilization of postrenal azotemia, however there is not yet a consensus about the ideal rate of fluid therapy after relief of urethral obstruction. Fifteen adult cats were divided in two groups: High Rate Group (HRG) and Low Rate Group (LRG). At predetermined time points was assessed venous blood pH, pCO2, pO2, bicarbonate concentration, BE, creatinine, BUN, Na+, K+ and urinary output. HRG had a lower glomerular filtration rate, characterized by a lower urinary output and a slower stabilization of BUN, creatinine, acidbase balance and potassium. The infusion of high rates of fluids in cats after a urethral obstruction must be undertaken with caution since it can lead to death due to the occurrence of pleural effusion and the absence of appropriate restoration of electrolyte balance and glomerular filtration. (Less)

Bilateral Changes of Spontaneous Activity Within the Central Auditory Pathway Upon Chronic Unilateral Intracochlear Electrical Stimulation.

In recent years, cochlear implants have been applied successfully for the treatment of unilateral hearing loss with quite surprising benefit. One reason for this successful treatment, including the relief from tinnitus, could be the normalization of spontaneous activity in the central auditory pathway because of the electrical stimulation. The present study, therefore, investigated at a cellular level, the effect of a unilateral chronic intracochlear stimulation on key structures of the central auditory pathway. Normal-hearing guinea pigs were mechanically single-sided deafened through a standard HiFocus1j electrode array (on a HiRes 90k cochlear implant) being inserted into the first turn of the cochlea. Four to five electrode contacts could be used for the stimulation. Six weeks after surgery, the speech processor (Auria) was fitted, based on tNRI values and mounted on the animal's back. The two experimental groups were stimulated 16 hours per day for 90 days, using a HiRes strategy based on different stimulation rates (low rate (275 pps/ch), high rate (5000 pps/ch)). The results were compared with those of unilateral deafened controls (implanted but not stimulated), as well as between the treatment groups. All animals experienced a standardized free field auditory environment. The low-rate group showed a significantly lower average spontaneous activity bilaterally in the dorsal cochlear nucleus and the medial geniculate body than the controls. However, there was no difference in the inferior colliculus and the primary auditory cortex. Spontaneous activity of the high-rate group was also reduced bilaterally in the dorsal cochlear nucleus and in the primary auditory cortex. No differences could be observed between the high-rate group and the controls in the contra-lateral inferior colliculus and medial geniculate body. The high-rate group showed bilaterally a higher activity in the CN and the MGB compared with the low-rate group, whereas in the IC and in the AC a trend for an opposite effect could be determined. Unilateral intracochlear electrical stimulation seems to facilitate the homeostasis of the network activity, since it decreases the spontaneous activity that is usually elevated upon deafferentiation. The electrical stimulation per se seems to be responsible for the bilateral changes described above, rather than the particular nature of the electrical stimulation (e.g., rate). The normalization effects of electrical stimulation found in the present study are of particular importance in cochlear implant recipients with single-sided deafness.

Effects of deafness and cochlear implant use on temporal response characteristics in cat primary auditory cortex

We have previously shown that neonatal deafness of 7–13 months duration leads to loss of cochleotopy in the primary auditory cortex (AI) that can be reversed by cochlear implant use. Here we describe the effects of a similar duration of deafness and cochlear implant use on temporal processing. Specifically, we compared the temporal resolution of neurons in AI of young adult normal-hearing cats that were acutely deafened and implanted immediately prior to recording with that in three groups of neonatally deafened cats. One group of neonatally deafened cats received no chronic stimulation. The other two groups received up to 8 months of either low- or high-rate (50 or 500 pulses per second per electrode, respectively) stimulation from a clinical cochlear implant, initiated at 10 weeks of age. Deafness of 7–13 months duration had no effect on the duration of post-onset response suppression, latency, latency jitter, or the stimulus repetition rate at which units responded maximally (best repetition rate), but resulted in a statistically significant reduction in the ability of units to respond to every stimulus in a train (maximum following rate). None of the temporal response characteristics of the low-rate group differed from those in acutely deafened controls. In contrast, high-rate stimulation had diverse effects: it resulted in decreased suppression duration, longer latency and greater jitter relative to all other groups, and an increase in best repetition rate and cut-off rate relative to acutely deafened controls. The minimal effects of moderate-duration deafness on temporal processing in the present study are in contrast to its previously-reported pronounced effects on cochleotopy. Much longer periods of deafness have been reported to result in significant changes in temporal processing, in accord with the fact that duration of deafness is a major factor influencing outcome in human cochlear implantees.

Criminal Trajectories and Risk Factors in a Canadian Sample of Offenders

This study contributed to the criminal trajectory literature using a Canadian-based sample of offenders and examined childhood and adolescent predictors of trajectory group membership. The sample comprised 378 males who had been sentenced as youth, between 1986 and 1996, to one of two open custody facilities in Toronto, Canada. Official criminal records were obtained from late childhood and early adolescence into adulthood for an average follow-up of 12.1 years. Childhood and adolescent predictors reflecting individual, family, peer, and school domains were extracted from client files. Trajectory analysis yielded four groups, labeled moderate rate (MR); low rate (LR); high-rate, adult peaked (HRADL); and high-rate, adolescence peaked (HRADOL). Multinomial regression analyses indicated that risk factors representing the family and peer domains differentiated the MR, HRADL, and HRADOL groups from the LR group. Moreover, whereas both child and adolescent risk factors were associated with the MR, HRADL, and HRADOL groups, only adolescent risk factors were associated with the LR group.

Criminal Trajectories of Adult Sex Offenders and the Age Effect: Examining the Dynamic Aspect of Offending in Adulthood

Several policies have been implemented to manage the risk of sex offenders in the community. These policies, however, tend to target older repeat sex offenders. This is the first study to examine and describe the offending trajectories of adult sex offenders from early adolescence to adulthood. The current study is based on a quasipopulation of convicted adult sex offenders in the province of Quebec, Canada. The number of convictions was examined from the period of adolescence up to age 35 using a group-based modeling technique. The study uncovered four offending trajectories: (a) very low-rate group (56%); (b) late-bloomers (12%); (c) low-rate desistors (25%); and (d) high-rate chronics (8%). These trajectories differed on several key criminal career dimensions such as age of onset, frequency, diversity, and specialization in different offence types. The study findings challenge the conception of sex offenders’ risk as high, stable, and linear. The implications for the risk assessment and the risk prediction of recidivism are discussed.

Own and Friends' Smoking Attitudes and Social Preference as Early Predictors of Adolescent Smoking

This study examined the role of friends' attitudes in adolescent smoking (N = 203). Growth mixture modeling was used to identify three trajectories of smoking behavior from ages 12 to 14 years: a low-rate group, an increasing-rate group, and a high-rate group. Adolescents' own and their friends' attitudes at age 11 years were not significantly related to smoking. However, in the increasing-rate group (compared with the low-rate group), friends' attitudes interacted with both adolescents' own and friends' social preference (i.e., likeability). The link between friends' attitudes and membership in the increasing-rate group was stronger for early adolescents with low social preference scores and for early adolescents with friends who had low social preference scores. Other than for the high-rate group, for which causal factors of smoking may be located early in childhood (e.g., family and personality or temperamental characteristics), the combination of low social preference and friends who hold a positive attitude toward smoking is associated with escalating cigarette use among young adolescents.

Survivin expression in early hepatocellular carcinoma and post-treatment with anti-cancer drug under hypoxic culture condition

To investigate the expression of survivin during the early stages of hepatocellular carcinoma (HCC). Immunohistochemical expression of survivin in liver tumor and non-tumor tissue specimens taken from 17 patients was compared. In addition, to determine the survivin expression in response to anti-cancer drugs in early stage HCC, the survivin expression was determined after the treatment of the HCC cells with anti-cancer drugs under hypoxic culture conditions. Survivin proteins were expressed in 64.7% of cells in early HCC specimens. A correlation between the survivin expression rate in the peritumoral hepatocytes and the rate of expression in the HCC specimens (low-rate group vs high-rate group) was observed. The survivin protein concentration in HCC cells was increased by the combination of hypoxia and anti-cancer drugs. This study suggests that survivin could be used as a therapeutic target in early HCC.

The effect of altering heart rate on ventricular function in patients with heart failure treated with β-blockers

Beta-blockers are effective for the treatment of heart failure, but their mechanism of action is unresolved. Heart rate reduction may be a central mechanism or a troublesome side effect. A randomized, double-blind, parallel group study comparing chronic higher-rate (80 pulses per minute) with lower-rate (60 pulses per minute) pacing in pacemaker-dependent patients with symptomatic left ventricular (LV) systolic dysfunction, receiving beta-blockers. Gated radionuclide ventriculography (RNVG) was performed at baseline and after at least 9 months. The primary outcome was change in LV volumes, as a marker of beneficial reverse remodeling, from baseline to follow-up. Forty-nine patients were randomized. Mean age was 74 +/- 6 years and with LV ejection fraction of 26% +/- 9% at baseline. During 14 +/- 13 months of follow-up, 21 patients (43%) died and 25 (51%) completed the study protocol: 12 in the higher-rate and 13 in the lower-rate group. Mean LV end-diastolic (higher rate +20 +/- 104 mL vs lower rate -65 +/- 92 mL, P = .03) and systolic (higher rate +29 +/- 83 mL vs lower rate -60 +/- 74 mL, P = .006) volumes increased with higher-rate versus lower-rate pacing, whereas LV ejection fraction declined (higher rate -4.2% +/- 4.4% vs lower rate +2.2% +/- 5.4%, P = .002). Reversal of beta-blocker-induced bradycardia has deleterious effects on ventricular function, suggesting heart rate reduction is an important mediator of their effects. The prognosis of patients with pacemakers and heart failure is poor.

医薬品の副作用検索におけるＭｅｄｌｉｎｅの利用性評価

Database usage was evaluated regarding the retrieval of drug-induced adverse effect case reports. A search of case reports was performed using the on-line Medline (Ovid). Forty case reports were extracted from “Reactions” (adis INTERNATIONAL) used as secondary literature on adverse effects. From the original titles and abstracts, the name of the drugs and adverse effects were translated into Japanease and used to search data sets. After 6 pharmacists received a 30-minute explanation on how to use Medline since they had no previous experience in using Medline at the time of this study, the accessibility to the original case reports was examined and evaluated for their hitting rates. The hitting rates of the original data were 40-75%, and the data was divided into high-rate and low-rate groups. A major cause of a low hitting rate was that the “explode” function was not utilized to extend the terms of adverse effects. As a result, the “explode” function was found to be an important factor in effectively using Medline, especially when terms are not adequately chosen to retrieve case reports on adverse effects.

Effects of ration on the maturation and fecundity in captive Atlantic herring (Clupea harengus)

We examined the effects of amount of food on vitellogenic oocyte size and number (fecundity) between two experimental groups of Atlantic herring (Clupea harengus) kept in separate but identical compartments of a large seawater tank. Growth and maturation were monitored for 1.5 years. Each group of 200 fish was fed exclusively on krill. At the end of the experiment, a high-ration group, fed 12 mg ·g fish-1 ·day-1, had similar weights-at-length as wild specimens of the same stock. A low-ration group fed about half the amount of the high-ration group had significantly lower weights-at-length. Ration had no effect on oocyte size and relative potential fecundity (oocytes per gram), but mean potential fecundity (oocytes per fish) of the low-ration fish was 26% lower than that of the high-ration fish. The relative intensity of early stages of atresia was quantified histologically. Atresia is a common phenomenon in Atlantic herring and increases markedly with suboptimal feeding. Mean relative atretic intensities were estimated at about 3 and 6% for the high- and low-ration groups, respectively, but with large intragroup variation. Modeled realized fecundity (spawned eggs per fish) indicated a 9 and 40% reduction compared with the measured potential fecundities, respectively.

Role of adiposity in food intake control of juvenile chinook salmon ( Oncorhynchus tshawytscha)

Experiments were conducted to determine if adiposity affected feed intake in juvenile chinook salmon ( Oncorhynchus tshawytscha) with different nutritional histories. Fry were fed high-fat (23%) or low-fat (3%) diets at high (satiation) and low (one-half satiation) ration levels for 7 months before the start of the intake experiment. This pre-treatment produced fish averaging 22 g with 11.3% (high-fat diet) and 5.4% (low-fat diet) body fat when fed to satiation or 11 g with 7.0% (high-fat diet) and 3.3% (low-fat diet) body fat when fed at one-half satiation. Experiment 1 had a 2 × 2 factorial design where duplicate groups of 20 fish from the high-ration groups (22 g) were fed high- (16%) or low- (4%) fat diets twice daily to satiation 6 days/wk for 3 weeks. Daily feed intake was recorded. The same protocol was used in experiment 2 on fish (40 fish per tank) from the smaller low-ration groups (11 g). Feed intakes on day 1, cumulative feed intakes after 21 days and plasma levels of insulin and insulin-like growth factor 1 (IGF-1) were compared using two-way ANOVA with initial whole body fat and dietary fat as the independent variables. In both experiments, high body fat led to significantly lower feed intake on day 1 and after 21 days of feeding. High dietary fat levels caused greater intake on day 1, but by the end of the experiments, this effect was not significant, suggesting some adaptation to the diets. Insulin in plasma showed greater response to dietary fat (high-fat diets causing higher insulin levels), whereas IGF-1 responded more to body fat level (high body fat led to higher IGF-1 levels). Our results show that in both-fast- and slow-growing juvenile chinook salmon, adiposity plays a role in regulation of feed intake and that adiposity appears to interact with IGF-1. Dietary fat levels had transient effects on intake, but plasma insulin levels consistently reflected the dietary fat levels. An important implication of our findings is that food intake, and possibly growth, could be retarded if a feeding regime results in high body fat levels.