Difference In Rate Of Increase Research Articles

Abstract 16966: Temporal Trends and Race Differences in Catheter Ablation for Atrial Fibrillation Among Patients With Heart Failure With Reduced Ejection Fraction Before and After CASTLE-AF

Background: Catheter ablation (CA) for atrial fibrillation (AF) reduced the risk of all-cause death or heart failure (HF) hospitalization among patients with HF with reduced ejection fraction (HFrEF) in the CASTLE-AF randomized trial. The trends in utilization of CA for AF in the setting of HFrEF before and after CASTLE-AF and whether disparities in CA by race have changed over time have not been well studied. Methods: Patients with AF and HFrEF from the GWTG-AF registry from 1/2016-6/2022 were included. Temporal trends in AF ablation in the overall cohort and across self-reported race-ethnicity groups (Black, White, and other) were examined using linear regression models with generalized estimating equations accounting for within-hospital clustering. Change in ablation rates following the CASTLE-AF publication (2/1/2018) were assessed using interrupted time-series analysis with linear splines with knots at the time of publication. Results: Overall, 26,678 patients (71.3±12.6 years, 45.4% Female, CHADS-VASc 1.3±0.6, 80.4% White) were included in the cohort. In the pre-Castle-AF period ablation rates were 5.2% with significantly lower rates of ablation in Black and other race patients compared with White patients (2.6% vs. 3.0% vs. 5.8%, respectively). The rates of CA increased post-CASTLE-AF (overall: 21.8%) and for each race group (Black: 20.3%, White: 22.6%, Other: 16.8%; Figure ) without significant difference in rate of increase across race groups (P-interaction for time*race = 0.82). Older age, female sex, non-White race, higher CHADS-VASc, and bleeding history were associated with less CA, while history of hypertension, obstructive sleep apnea, and the post-CASTLE-AF time period were associated with more CA. Conclusion: CA rates significantly increased post-CASTLE-AF among the entire cohort and across all race-ethnicity groups, however, non-White race was associated with lower utilization of CA over the entire period.

Association of the End-Stage Renal Disease Treatment Choices Payment Model With Home Dialysis Use at Kidney Failure Onset From 2016 to 2022

The Centers for Medicare & Medicaid Services designed a mandatory payment model to incentivize home dialysis use: the End-Stage Renal Disease Treatment Choices (ETC). Outpatient dialysis facilities and health care professionals providing nephrology services were randomly assigned to ETC participation at the hospital referral region level. To assess the association between ETC and home dialysis use in the incident dialysis population in its first 18 months of implementation. A cohort study with controlled, interrupted time series analysis of the US End-Stage Renal Disease Quality Reporting System database was conducted, using generalized estimating equations. All adults initiating home-based dialysis in the US between January 1, 2016, and June 30, 2022, without a prior kidney transplant were included in the analysis. Prior to vs after ETC onset in January 1, 2021, and random assignment to ETC participation of facilities and health care professionals involved in patient care. Percentage of patients started on incident home dialysis and yearly change in percentage initiating home dialysis. A total of 817 177 adults initiated home dialysis during the study period, of whom 750 314 were included in the study cohort. The cohort included 41.4% women; 26.2% of the patients were Black, 17.4% were Hispanic, and 49.1% were White. Approximately half (49.6%) of the patients were aged at least 65 years. A total of 31.2% received care from health care professionals assigned to ETC participation, and 33.6% had Medicare fee-for-service coverage. Overall, home dialysis use increased from 10.0% in January 2016 to 17.4% in June 2022. Home dialysis use increased more in ETC markets than in non-ETC markets after January 2021 (by 1.07%; 95% CI, 0.16%-1.97%). The rate of increase in home dialysis use in the entire cohort nearly doubled after January 2021 to 1.66% per year (95% CI, 1.14%-2.19%) compared with before 2021, when the rate was 0.86% per year (95% CI, 0.75%-0.97%), but the difference in rate of increase in home dialysis use was not significant between ETC and non-ETC markets. This study noted that, although the overall rate of dialysis use at home was greater after ETC implementation, the increase occurred more among patients in ETC markets than among those in non-ETC markets. These findings suggest that federal policy and financial incentives affected care for the entire incident dialysis population in the US.

Improved cyber-physical system captured post-flowering high night temperature impact on yield and quality of field grown wheat

Winter wheat (Triticum aestivum L.) is essential to maintain food security for a large proportion of the world’s population. With increased risk from abiotic stresses due to climate variability, it is imperative to understand and minimize the negative impact of these stressors, including high night temperature (HNT). Both globally and at regional scales, a differential rate of increase in day and night temperature is observed, wherein night temperatures are increasing at a higher pace and the trend is projected to continue into the future. Previous studies using controlled environment facilities and small field-based removable chambers have shown that post-anthesis HNT stress can induce a significant reduction in wheat grain yield. A prototype was previously developed by utilizing field-based tents allowing for simultaneous phenotyping of popular winter wheat varieties from US Midwest and advanced breeding lines. Hence, the objectives of the study were to (i) design and build a new field-based infrastructure and test and validate the uniformity of HNT stress application on a scaled-up version of the prototype (ii) improve and develop a more sophisticated cyber-physical system to sense and impose post-anthesis HNT stress uniformly through physiological maturity within the scaled-up tents; and (iii) determine the impact of HNT stress during grain filling on the agronomic and grain quality parameters including starch and protein concentration. The system imposed a consistent post-anthesis HNT stress of + 3.8 °C until maturity and maintained uniform distribution of stress which was confirmed by (i) 0.23 °C temperature differential between an array of sensors within the tents and (ii) statistically similar performance of a common check replicated multiple times in each tent. On average, a reduction in grain-filling duration by 3.33 days, kernel weight by 1.25% per °C, grain number by 2.36% per °C and yield by 3.58% per °C increase in night temperature was documented. HNT stress induced a significant reduction in starch concentration indicating disturbed carbon balance. The pilot field-based facility integrated with a robust cyber-physical system provides a timely breakthrough for evaluating HNT stress impact on large diversity panels to enhance HNT stress tolerance across field crops. The flexibility of the cyber-physical system and movement capabilities of the field-based infrastructure allows this methodology to be adaptable to different crops.

Effects of prolonged mass rearing on life history traits of Habrobracon hebetor (Hymenoptera: Braconidae)

Long-term mass rearing of parasitoids under laboratory conditions may affect their quality. We studied the quality of Habrobracon hebetor (Say) (Hymenoptera: Braconidae) reared for more than 20 generations (G) using two-sex life table parameters. We found that G2 had the longest pre-adult development time (12.4 d) and the highest fecundity (1304.00 eggs/female) compared with the other generations. While no significant differences in the intrinsic rate of increase (r) and net reproductive rate (R 0) were found among G4, G6, G8, G15, and G20, the highest values of r (0.3273 day−1) and R 0 (436.28 eggs/individual) as well as the shortest mean generation time (T) were observed in G10. In addition, significant differences in sex ratio (F/F + M) were observed among different generations, ranging from 17% in G2 to 60% in G10. These results suggest that up to a certain number of generations (G10), the quality of H. hebetor significantly increased without adding field-collected parasitoids or changing the factitious host. To maintain the quality of the colony beyond this point, it should be rejuvenated by periodically adding field-collected individuals.

The trends of population general morbidity in the subjects of the Central Federal Okrug of the Russian Federation

The article presents the results of analysis of indices of total morbidity of population of the Central Federal Okrug (CFD) of the Russian Federation in 2010-2017. The significant differences in indices of total morbidity between the CFD subjects in certain ICD-10 classes were established. The indices of total morbidity of population during study period (8 years) in the Central Federal District factually didn't altered, while dynamics of indices in other subjects was characterized by multidirectionality. The gap in levels of total morbidity of population in the subjects was significant: from 115,123.6 per 100,000 of population in the Kursk Oblast to 194,404.1 per 100,000 of population in the Orel Oblast. The significant difference in rates of increase/ decrease of indices is noted. Thus, in Moscow decrease rate made up to 10%, while in the Orel Oblast morbidity increased up to 13.1%. Besides, in 2017, the Orel Region took a leadership in rate of increasing of total morbidity in such classes of diseases as infectious and parasitic diseases (39.3%), diseases of blood and blood-forming organs (49.1%), diseases of endocrine system (59,1%), diseases of nervous system (26.8%), diseases of respiratory system (28.2%), diseases of musculoskeletal system (16%), malformations (56%). It is very likely that this trend developed under influence of demographic situation in the subject due to significant increasing of percentage of people older than able-bodied age. The city of Moscow occupies leading position in decreasing of rate of prevalence of diseases and last but one place in level of total morbidity being inferior only to the Kursk Oblast. Thus, in Moscow was noted the most significant decreasing of morbidity in classes of infectious and parasitic diseases (26%) and diseases of digestive system (20.6%). The diseases of blood and blood-forming organs (235.2 per 100,000 population) and mental disorders (2353.5 per 100,000 population) were registered the less. The main contribution into trends of increasing or decreasing of indices is made by persons aged 18 years and older (74.1%).

Changes in carotid artery intima-media thickness 3 years after cessation of menopausal hormone therapy: follow-up from the Kronos Early Estrogen Prevention Study.

Little is known regarding the progression of preclinical atherosclerosis upon cessation of menopausal hormone therapy (MHT). This study evaluated changes in carotid artery intima-media thickness (CIMT) in a subgroup of participants during 4 years and 3 years after the Kronos Early Estrogen Prevention Study (KEEPS). Of the women enrolled in KEEPS at Mayo Clinic (n = 118), a subset (n = 76) agreed to participate in this follow-up study. KEEPS MHT assignments were placebo (PBO), n = 33; transdermal 17β-estradiol (tE2), n = 23; and oral conjugated equine estrogens group (oCEE), n = 20. CIMT was measured by B-mode ultrasonography. Longitudinal analysis of CIMT was performed using all available data from pre-, on-, and post-treatment periods. At 7 years, median age of participants was 60.2 years; median time since menopause was 8.5 years. The mean difference in rates of increase was significantly greater over the post- than on-treatment period within the oCEE group (0.010 [0.002-0.017] mm/y), but not within the PBO (0.006 [-0.001 to 0.012] mm/y; P = 0.072) or tE2 (0.002 [-0.005 to 0.010] mm/y; P = 0.312) groups. There were, however, no significant treatment differences in the linear trends over those intervals (P = 0.524). Cessation of MHT at the lower doses and formulations used in KEEPS did not appear to alter the trajectory of CIMT over a 3-year follow-up period. CIMT, however, increased in all groups over the entire 7-year timeframe as expected with age and timing of menopause possibly key contributors.

Incidence trends and patterns of breast cancer in Sri Lanka: an analysis of the national cancer database

BackgroundA gradual decline in the incidence of breast cancer is documented in developed countries especially over last two decades, while in developing countries the incidence continues to rise. We conducted this study to examine trends in incidence of breast cancer in a developing country, Sri Lanka.MethodsA retrospective cohort evaluation of patients with breast cancer during 2001–2010 was performed using population based data from the Sri Lanka National Cancer Registry. Trends in incidence were analysed using Joinpoint regression analysis.ResultsThe age standardized incidence of female breast cancer in Sri Lanka appears to have increased from 17.3 per 100,000 in 2001 (95% confidence interval [95% CI] 16.5–18.2) to 24.7 per 100,000 in 2010 (95% CI 23.7–25.7); a 1.4-fold increase (p < 0.05) with an estimated annual percentage change (EAPC) of 4.4 (95% CI 3.3–5.5). Highest incidence of breast cancer was seen among women of 60 to 64-year age group which has increased from 68.1 to 100.2 per 100,000 over this period (EAPC 4.6%, 95% CI 3.9–5.2, p < 0.001 for trend). A substantially greater increase was observed among women older than 50 years (from 50.4 to 76.9 per 100,000; EAPC 5.5, 95% CI 4.1–7.0, p < 0.05) compared with women younger than 50 years (from 32.0 to 39.6 per 100,000; EAPC 2.3, 95% CI 1.1–3.5, p < 0.05).ConclusionsA gradual but a significant increase in the incidence of female breast cancer is observed in Sri Lanka. A rapid rise in the breast cancer incidence among post-menopausal women appears to be the major contributor towards this increase. Improving cancer data collection appears to have been a contributor to the observed increase. However, an inherent increase is also likely as differential rates of increase were observed by age groups. Further research is needed to identify the reasons for the observed increase which may help with future cancer control efforts in Sri Lanka.

Field Crops and the Fear of Heat Stress – Opportunities, Challenges and Future Directions

The increased probability of occurrence of more intense and frequent heat stress episodes and extended warmer nights in the future are major challenges towards sustaining agricultural production. Cereals, millets and oil seed crops respond differently to increasing temperature at different growth and developmental stages but are highly susceptible to heat stress during the gametogenesis and the flowering stages. Interestingly, the duration of stress exposure induces differential responses i.e. season-long exposure to high-temperature and short episodes of heat stress coinciding with reproductive processes. Season-long high-temperature stress decreased biomass production, seed number, individual seed weight and yield of all grain crops. Short duration heat stress coinciding with either gametogenesis or anthesis leads to negative impact of seed-set, while stress exposure at post-anthesis stages decreased seed filling duration leading to decreased seed weight. Based on extensive research we have identified temperature thresholds across field crops and quantified the above changes. Impact of heat stress on pollen production, pollen viability, pollen lipid profiles, alternations in the pollen and stigmatic surface, pollen reactive oxygen species production, their membrane damage etc., differentiating contrasting cultivars across different field crops will be highlighted. In addition, considering the differential rate of increase in minimum night temperature, different physiological routes inducing yield losses under high day and high night temperature will be presented. Genetic variability across field crops in response to heat stress and more interestingly options from wild species of wheat (higher heat tolerance at flowering), rice (heat escape through early morning flowering) and their usefulness in heat stress tolerance breeding will be an interesting addition to our talk. The current progress achieved, opportunities available, unaddressed challenges and future direction of research that could help in crop improvement to sustain global food production under future hotter climates will be discussed.

Decadal Changes in Soil Carbon and Nitrogen under a Range of Irrigation and Phosphorus Fertilizer Treatments

We determined decadal changes in soil carbon (C) and nitrogen (N) due to different irrigation regimes and phosphorus fertilization of pastures. Archived soil samples (0–75 mm) collected annually from two long‐term trials in New Zealand were analyzed for %C and %N from three P input treatments (ranging from 0 to 376 kg superphosphate ha−1 yr−1, 1952–2009) and three irrigation treatments (unirrigated and irrigated when soil moisture content fell below either 10 or 20%, 1959–2002). In the fertilizer trial, soil C increased linearly from 2.7 to 4.2%, and there was no difference in rates of increase in C between treatments, despite much greater aboveground production when P was added. This lack of difference was attributed to higher stocking rates on treatments with higher production, and to the possibility that root inputs (which differed less between treatments) was a more important control of soil C accumulation. Nitrogen (%) was lower in the unfertilized than fertilized treatments due to lower clover N fixation, which was constrained by P availability. Soil C (%) was significantly greater in the unirrigated treatment than the irrigated treatments throughout the trial. Aboveground production was much greater in the irrigated than dryland treatment but root biomass was lower. Irrigation must have increased C and N losses, possibly via increased respiration rates during seasonally dry periods. Our study showed that P fertilizer application did not result in an increase in surface soil C and that flood irrigation resulted in a constrained increase in surface soil C content.

Injectable synthetic bone substitute and distal radius surgery: prospective continue study on comminutive fracture and extra articular malunion

medical use of particular signaling molecules as inducers of regeneration can induce significant tissue regeneration. Fibroblast growth factor 2 (FGF-2) displays strong angiogenic activity and the ability to stimulate mesenchymal cells into proliferating. Especially in Japan, many fundamental studies have been performed to apply FGF-2 in a clinical setting. A randomized, double-blinded clinical trial involving placebos and multiple dental facilities was performed from 2005 to 2007 to both clarify the activity of FGF-2 to regenerate periodontal tissue in periodontitis patients and confirm drug safety. From among those patients we discuss about the 7 patients treated in our hospital. Materials and Methods: Patients were diagnosed with 2or 3-walled intrabony defect according to radiography at the screening. Patients provided written informed consent. They were randomly assigned to 4 groups: Group P, given vehicle only with no FGF-2; Group L, given HPC containing 0.2% FGF-2; Group M, given HPC containing 0.3% FGF-2; and Group H, given HPC containing 0.4% FGF-2. The patients underwent periodontal surgical treatment (modified Widman flap operations) during which we also administered 200 μL of the appropriate investigational drug to sites displaying periodontal tissue defect. To evaluate efficacy of the investigational drug, all patients underwent standardized radiography of the region under investigation before and for 72 weeks following administration of the investigational drug. This study was initiated following the institutional review board (IRB) approvals and performed in compliance with good clinical practices (GCP). Result: Major difference in rate of increase in alveolar bone height at the defect region was identified between Group P (8.21%, n=4) and Group H (73.94%, n=3) at 72 weeks. Throughout the investigation period, no serious adverse event causal with the investigational drug was identified. Conclusions: These results suggest that some efficacy can be expected from FGF-2 on induced regeneration of periodontal tissue in patients with periodontitis displaying 2or 3-walled intrabony defects. Disclosure of Interest: None declared

Periodontal Tissue Regeneration Using Fibroblast Growth Factor -2: Randomized Controlled Phase II Clinical Trial

BackgroundThe options for medical use of signaling molecules as stimulators of tissue regeneration are currently limited. Preclinical evidence suggests that fibroblast growth factor (FGF)-2 can promote periodontal regeneration. This study aimed to clarify the activity of FGF-2 in stimulating regeneration of periodontal tissue lost by periodontitis and to evaluate the safety of such stimulation.Methodology/Principal FindingsWe used recombinant human FGF-2 with 3% hydroxypropylcellulose (HPC) as vehicle and conducted a randomized double-blinded controlled trial involving 13 facilities. Subjects comprised 74 patients displaying a 2- or 3-walled vertical bone defect as measured ≥3 mm apical to the bone crest. Patients were randomly assigned to 4 groups: Group P, given HPC with no FGF-2; Group L, given HPC containing 0.03% FGF-2; Group M, given HPC containing 0.1% FGF-2; and Group H, given HPC containing 0.3% FGF-2. Each patient underwent flap operation during which we administered 200 µL of the appropriate investigational drug to the bone defect. Before and for 36 weeks following administration, patients underwent periodontal tissue inspections and standardized radiography of the region under investigation. As a result, a significant difference (p = 0.021) in rate of increase in alveolar bone height was identified between Group P (23.92%) and Group H (58.62%) at 36 weeks. The linear increase in alveolar bone height at 36 weeks in Group P and H was 0.95 mm and 1.85 mm, respectively (p = 0.132). No serious adverse events attributable to the investigational drug were identified.ConclusionsAlthough no statistically significant differences were noted for gains in clinical attachment level and alveolar bone gain for FGF-2 groups versus Group P, the significant difference in rate of increase in alveolar bone height (p = 0.021) between Groups P and H at 36 weeks suggests that some efficacy could be expected from FGF-2 in stimulating regeneration of periodontal tissue in patients with periodontitis.Trial RegistrationClinicalTrials.gov NCT00514657

Regional cerebral blood flow measured by the resting and vascular reserve (RVR) method in chronic alcoholics.

It has been reported that cerebral blood flow is decreased in chronic alcoholics without neurological diseases. We performed SPECT by the resting and vascular reserve (RVR) method in 11 chronic alcoholics (mean age 59.1 +/- 10.4, all males) and 11 age-matched healthy controls (mean age 58.8 +/- 10.1, all males). The resting and vascular reserve (RVR) method is a consecutive (99m)Tc-ECD SPECT study before and after acetazolamide administration with adjunctive radionuclide angiography, which is easy to perform for a routine clinical study and quite useful for evaluating regional cerebral blood flow and the cerebrovascular response to acetazolamide. Regional cerebral blood flows in almost all regions in the alcoholic group were lower than those in the control group. However, there were no significant differences in increased rates of blood flow in response to acetazolamide in almost all regions between the chronic alcoholic group and the control group. In both groups, the increased rates of blood flow in response to acetazolamide in the supratentorial region, cerebellum, and brain stem were 30-40%, 20-25%, and 42-48%, respectively. The cerebrovascular response to acetazolamide in chronic alcoholics was not impaired, therefore the reduction of brain metabolism may be one of the important factors causing the decreased cerebral blood flow in chronic alcoholics.

The evolution of airway function in early childhood following clinical diagnosis of cystic fibrosis.

This study aimed to investigate the evolution of airway function in infants newly diagnosed with cystic fibrosis (CF). FEV(0.5) was measured soon after diagnosis (median age of 28 weeks) and 6 months later in subjects with CF and on two occasions 6 months apart (median ages of 7.4 and 33.7 weeks) in healthy infants, using the raised-volume technique. Repeated measurements were successful in 34 CF and 32 healthy subjects. After adjustment for age, length, sex, and exposure to maternal smoking, mean FEV(0.5) was significantly lower in infants with CF both shortly after diagnosis and at the second test, with no significant difference in rate of increase in FEV(0.5) with growth between the two groups. When compared with published reference data, FEV(0.5) was reduced by an average of two z scores on both test occasions in those with CF, with 72% of individuals having an FEV(0.5) of less than 1.64 z-scores (i.e., less than the fifth percentile) on one or both test occasions. On longitudinal analysis, subjects with CF experienced a mean (95% confidence interval) reduction in FEV(0.5) of 20% (11, 28). Airway function is diminished soon after diagnosis in infants with CF and does not catch up during infancy and early childhood. These findings have important implications for early interventions in CF.

Reconciling heart disease mortality and ICD codes

This study uses 61 years of death certificates for Bexar County, Texas, uniformly coded under ICD 9, to describe the transition in heart disease mortality from 1935-1995. We find that life expectancy for persons dying with heart diseases increased throughout this period, with clear differences in rates of increase for males and females, associated with acute ischemic heart disease. Our data point to an epidemic of AIHD in the 1950s and 1960s, which is now abating. Findings are less clear for chronic ischemic heart disease, while other major heart diseases cannot be traced with any confidence owing to changes over time in the emphasis accorded particular causes. Our findings suggest caution with respect to the socioeconomic analysis of heart disease mortality data, particularly where the instability of the coding conventions has been most acute.

Escape from gregarine parasites affects the competitive interactions of an invasive mosquito.

When a species is introduced into a new location, it may escape, at least temporarily, from its natural enemies. In field surveys, we found that when the exotic, invasive mosquito, Aedes albopictus, invades new sites, it initially experiences reduced infection by its gut parasite, Ascogregarina taiwanensis. To determine the effect of this escape from parasitism on the competitive ability of A. albopictus, we performed a laboratory competition experiment in which infected and uninfected A. albopictus larvae were reared in microcosms alone and in competition with larvae of the native mosquito, Ochlerotatus triseriatus. We analyzed the effect of parasitism by A. taiwanensis on A. albopictus performance when subjected to intra- and interspecific competition across a range of larval densities, as well as the effect of A. albopictus parasitism by A. taiwanensis on the competitive impact of A. albopictus on O. triseriatus. At a density of 30 O. triseriatus larvae, O. triseriatus survivorship was significantly reduced by the addition of 30 unifected A. albopictus, but not by addition of 30 infected A. albopictus, and not by addition of 15 A. albopictus whether infected or uninfected. Although estimated finite rate of population increase (λ') showed similar trends, and was significantly affected by treatments, no pairwise differences in rate of increase were significant. Infection by A. taiwanensis also significantly prolonged A. albopictus female development time and reduced the intraspecific competitive effect of increased density of A. albopictus, but did not affect A. albopictus survivorship, mass, or estimated finite rate of population increase. Thus, when A. albopictus escapes from this parasite as it colonizes new sites, this escape may give it a small, but significant, added competitive advantage over O. triseriatus, which may facilitate range expansion of A. albopictus and enhance A. albopictus's initial impact on resident species.

Strategic sperm allocation in the Small White butterfly Pieris rapae (Lepidoptera: Pieridae)

1. In species where females mate multiply, it is important for males to recuperate quickly in order to maximize their fertilization success. Butterflies produce a spermatophore at mating containing accessory secretions and sperm of two types: a large number of non‐fertile ‘apyrene’ sperm and fewer fertile ‘eupyrene’ sperm. Many butterfly species eclose with most nutrients for reproduction already present. Males must therefore decide how to allocate resources to the various spermatophore components at any given mating. 2. Recovery rates of apyrene and eupyrene sperm number and spermatophore size was studied in the polyandrous Small White butterfly Pieris rapae. The mass of the first spermatophore increases with time since eclosion, as does the number of both types of sperm. Similarly, on a male's second mating, both the mass of the spermatophore and the number of sperm increases with time since the first mating. 3. However, the rate of increase in eupyrene sperm numbers is higher after the first mating. The difference in rate of increase may be the result of different probabilities of virgin and non‐virgin males obtaining future matings. 4. Males have a sperm storage organ, the duplex, in which they retain sperm after their first mating. This ensures that high sperm numbers are available for their second mating, even when remating only 1 h later. Thus, males do not ejaculate all available sperm on any given mating, and seem to have different strategies on their first and second matings. 5. It can be argued that Small White butterfly males allocate sperm strategically according to the probability of obtaining subsequent matings, and the level of sperm competition.

Clearance of Albumin by Cortical Bone and Marrow

Male Sprague-Dawley rats, approximately 300 g, were anesthetized. The jugular vein and carotid artery were cannulated and the left femoral vein was exposed. The femoral vein was then ligated, and 2 minutes later albumin, labeled with 125I, was injected. The albumin was allowed to equilibrate in the vascular system for 3 minutes, and then 1 group of animals was euthanized. Further groups of animals were euthanized after 15, 30, and 60 minutes. Tibias were removed from both legs together with samples of muscle and liver. The tibias were separated into diaphyseal cortex, marrow, and proximal and distal ends. All tissue samples and terminal blood samples were counted for radioactivity, and volumes of distribution were calculated. In cortical bone the volume distribution increased from an initial value of 12.9 +/- 1.1 microL/g to 18.6 +/- 2.5 microL/g at 30 minutes in the control leg (mean +/- standard error of the mean, n = 5). In the congested leg, the volume of distribution increased from 10.6 +/- 0.6 to 19.6 +/- 2.1 microL/g during the same time interval. The difference in rate of increase between the congested and control leg was not statistically significant. Albumin seemed to equilibrate within 3 minutes within the marrow. The data are consistent with the hypothesis that macromolecular transport in the interstitial fluid of cortical bone is coupled to convectional flow from endosteal to periosteal surface. This data may help to understand mechanisms by which venous hypertension has been shown to stimulate bone growth and fracture repair, and also the distribution of bone density changes observed after prolonged exposure to microgravity.

Prevalence of Prostatism in Japanese Men in a Community-based Study with Comparison to a Similar American Study

Purpose We estimate the prevalence of urinary symptoms in Japanese men. Materials and Methods A total of 289 eligible residents 40 to 79 years old completed a questionnaire with questions worded similarly to those of the international prostate symptom score (response rate 42 percent). Results The ratio of moderate-to-severe symptoms was 41 percent, 29 percent, 31 percent and 56 percent for each age decade from ages 40 to 79 years, respectively, after adjusting for nonresponse. Within each age decade the median international prostatic symptom score was higher for Japanese men than for United States men with little difference in rates of increase with participant age or bother. Conclusion Lower urinary tract symptoms were common in Japanese men, with age-related increases similar to those of United States men.

Numerical simulation of the temperature dependence of the sidegating effect in GaAs MESFETs

The temperature dependence of the sidegating effect in GaAs devices has been investigated by performing two-dimensional numerical simulations on realistic structures. The less sidegating and the higher sidegating threshold at higher temperatures are found to be caused by the temperature-dependent trapping properties of the deep traps and the difference in increase rate with temperature of the currents in various current paths. These results provide further support to the sidegating picture in which Schottky contacts on the semi-insulating substrate play an important role.

Bacterioplankton cell growth and macromolecular synthesis in seawater cultures during the North Atlantic Spring Phytoplankton Bloom, May, 1989

We performed a series of seawater culture experiments on surface mixed layer samples during the spring phytoplankton bloom in the North Atlantic Ocean. Diluted (20% unfiltered + 80% 0.22 μm filtered) and untreated "whole" seawater samples were incubated up to 40 hour and sampled periodically for cell numbers, biovolume, and incorporation of (3)H-thymidine and -leucine. Abundance and biovolume increased exponentially at similar rates in diluted and whole samples, suggesting that removal by bacteriovores was low compared with growth. The exponential increase in biovolume was due to increases in cell numbers and mean cell volume. Generation times (i.e., 0.693/μ) averaged 36-53 hour in these surface (10 m) samples. Ninety percent of the tritiated thymidine incorporation (TTI) into cold trichloroacetic acid-insoluble cell fractions was recovered after extraction with NaOH and phenolchloroform, indicating that catabolism of thymidine and its appearance in RNA or protein was very low. The percentage of thymidine recovered in DNA did not change over the 40 hour of incubation and was the same as in water column samples. Rates of thymidine and leucine incorporation also increased exponentially. Incorporation rates tended to increase more rapidly than cell numbers or biovolume, though the differences were not significantly different, due to the small number of samples and variability over the time courses. Differential rates of increase in cellular properties during growth might indicate a lack of coupling between incorporation and production over time scales of hours-days. This in turn may reflect unbalanced growth of bacterial assemblages, which is an adaptation to variable conditions in the upper ocean in this season. Nonequality of rate constants for cells and incorporation yields conversion factors that are either higher or lower than would be calculated from balanced growth (i.e., rates of increase in numbers and incorporation rates equal), depending on the calculation approach chosen. An alternative approach to calculating conversion factors (the modified derivative approach) is proposed, which is insensitive to differential rates of increase of abundance and incorporation.