Mortality among veterans with type 2 diabetes initiating metformin, sulfonylurea or rosiglitazone monotherapy

AIMS/HYPOTHESES

Despite oral hypoglycaemic medications being the most commonly used pharmacological treatments for type 2 diabetes, research is limited on their comparative safety, particularly their effects on overall mortality. We compared mortality risk with monotherapy initiation of four oral hypoglycaemic medications in a nationwide cohort of US veterans with type 2 diabetes.

METHODS

We identified new users of oral hypoglycaemic medication monotherapy between 2004 and 2009 who received care for at least 1 year from the Veterans Health Administration.Patients were followed until initial monotherapy discontinuation,addition of another diabetes pharmacotherapy, death or end of follow-up. Mortality HRs were estimated using Cox regression adjusted for potential confounding factors.

RESULTS

Among new users of metformin, sulfonylureas and rosiglitazone (185,360 men, 7,812 women), 4,256 (2.2%) died during follow-up. Average duration of medication use ranged from 1.4 to 1.7 years. Significantly higher mortality risk was seen for glibenclamide (known as glyburide in the USA and Canada) (HR 1.38, 95% CI 1.27, 1.50) or glipizide (HR 1.55,95% CI 1.43, 1.67) compared with metformin monotherapy,and for glipizide compared with rosiglitazone (HR 1.27, 95%CI 1.01, 1.59) or glibenclamide monotherapy (HR 1.12, 95%CI 1.02, 1.23). A significant sex–rosiglitazone interaction was seen (p=0.034) compared with metformin monotherapy, with women having a higher HR (HR 4.36, 95% CI 1.34, 14.20)than men (HR 1.19, 95% CI 0.95, 1.49).

CONCLUSIONS/INTERPRETATIONS

Significantly higher mortality was associated with glibenclamide, glipizide and rosiglitazone use compared with metformin, and with glipizide use compared with rosiglitazone or glibenclamide. The potential for residual confounding by indication should be considered in interpreting these results.

SU-E-T-158: Neutron Damage of Power Electronics Used during Image Guidance in Proton Therapy

PURPOSE

A series of measurements were performed in a clinical proton therapy beam to assess the sensitivity of silicon-based electronics in commercial x-ray generators to single event burnout from the secondary neutron background in proton therapy treatments.

METHODS

Failure rates were nondestructively measured in various metal oxide semiconductor field-effect transistors (MOSFETs) as a function of applied voltage using a dedicated test circuit board. Neutrons were produced by 230 MeV protons stopping in a brass beam target and high beam current was used to accelerate testing. Neutron fluences were measured by activation analysis of carbon and aluminum in both the test setup and in situ at the generator. Failure rates were determined by scaling results based on beam monitor output to the relevant neutron fluence rate.

RESULTS

Current pulses from the test board clearly indicated the onset of single event burnout without destroying the MOSFET. The neutron fluence measured on the test board was 4.3 ± 0.8×106 n cm-2 MU-1 and this is consistent with previous measurements. The MOSFET failure rate decreased rapidly with a reduction in the applied voltage and is 20-30 times lower in higher-rated components at the same voltage. Under nominal operating conditions the estimated failure rate is tens of failures per year for a generator 6m from the treatment position.

CONCLUSION

The sensitivity of x-ray generator power electronics to neutron-induced single-event burnout is significant and can affect the implementation of image-guided techniques for proton therapy. Strategies and system designs to mitigate this phenomenon are being investigated to help enable x-ray generators withstand the proton therapy environment. This research was supported by the NIH/NCI under grant number 6-PO1 CA 21239.

IRT-Sofia BNCT beam tube optimization study

An optimization study of IRT-Sofia BNCT beam tube is presented. In the study we used the MIT/FCB experience. The enlarging of filter/moderator cross section dimensions and the decreasing of collimator length within the limits of the IRT-Sofia reactor design were analyzed. The influence of beam and reactor core axes non-coincidence on the beam properties was also evaluated. The irradiation resistance of polytetrafluoroethylene (Teflon(®)) was also evaluated. The results provide information for making decisions on the IRT-Sofia BNCT beam construction.

Survival and neurodevelopmental morbidity at 1 year of age following extremely preterm delivery over a 20-year period: a single centre cohort study

AIM

To assess survival and neurodevelopmental outcome of extremely preterm infants over a 20-year period at a single tertiary neonatal centre.

METHODS

All infants between 22 and 25(+6) weeks of gestation admitted to a single UK neonatal centre between 1981 and 2000 were enrolled prospectively. Infants in the same gestational age range who were born alive at the hospital but not admitted to the neonatal unit were also identified over the period 1991-2000. All surviving infants received neurological and developmental assessment at a corrected age of 1 year.

RESULTS

There was a progressive increase in survival at all gestational ages over the 20-year period. Overall survival rose from 32% to 71% as a proportion of all admissions. The proportion of survivors with adverse neurodevelopmental outcome at 1 year of age showed no consistent change over the same period.

CONCLUSION

In this single centre cohort study, marked improvements in survival over a 20-year period were not accompanied by a significant increase in neurodevelopmental morbidity.

Intravascular pressure and diameter profile of the utero-ovarian resistance artery network: estrous cycle-dependent modulation of resistance artery tone

Blood flow to the ovary varies dramatically in both magnitude and distribution throughout the estrous cycle to meet the hormonal and metabolic demands of the ovarian parenchyma as it cyclically develops and regresses. Several vascular components appear to be critical to vascular regulation of the ovary. As a first step in resolving the role of the resistance arteries and their paired veins in regulating ovarian blood flow and transvascular exchange, we characterized the architecture and intravascular pressure profile of the utero-ovarian resistance artery network in an in vivo preparation of the ovary of the anesthetized Golden hamster. We also investigated estrous cycle-dependent changes in resistance artery tone. The right ovary and the cranial aspect of the uterus in 26 female hamsters were exposed for microcirculatory observations. Estrous-cycle phase was determined in each animal before experimentation. The utero-ovarian vascular architecture was determined and resistance artery diameters were measured in each animal by video microscopy. Servo-null intravascular pressure measurements were made throughout the uteroovarian arterial network in 11 of the animals. Architectural data showed a complex anastomotic network jointly supplying the uterus and ovary. Resistance arteries showed a high degree of coiling and close apposition to veins, maximizing countercurrent-exchange capabilities. Arterial pressure dropped below 60% of systemic arterial pressure before the arteries entered the ovary. Both the ovarian artery and the uterine artery, which jointly feed the ovary, showed cycle day-dependent changes in diameter. Arterial diameters were smallest on the day following ovulation, during the brief luteal phase of the hamster. The data show that resistance arteries comprise a critical part of a complex network designed for intimate local communication and control and suggest that these arteries may play an important role in regulating ovarian blood flow in an estrous cycle-specific manner.

Effects of age and liveweight of dairy heifers at first calving on multiple lactation production

This paper reports on both the individual and combined effects of age and liveweight at first calving (AFC and LWFC, respectively) for Australian Holstein–Friesian heifers on multiple lactation production. One hundred and thirty-five heifers were allocated to 1 of 3 AFC treatments. Within each AFC treatment, heifers were randomly assigned to 1 of 3 LWFC treatments. From 16 weeks of age until first calving, heifers in all groups grazed pasture and were provided with supplementary feed when the quantity and quality of pasture was inadequate to meet growth requirements. Mean AFC and LWFC achieved were 25.1 ± 0.121, 29.9 ± 0.11 and 33.9 ± 0.09 months and 498 ± 4.09, 549 ± 5.40 and 595 ± 5.09 kg, respectively. As AFC increased, total production over the first 3 lactations increased. For each month's delay in AFC an extra 56.7 L milk, 1.78 kg milk fat, 1.45 kg milk protein and 3.23 kg fat + protein over the first 3 lactations was produced but by the third lactation the response was minimal. By end of third lactation the remaining heifers that calved at 25.1 months AFC were producing similar amounts to those that calved at the older AFC. As LWFC increased from 498 to 595 kg, production over the first 3 lactations increased. The response to an extra kilogram increase in LWFC was 4.82 L milk, 0.20 kg milk fat, 0.18 kg milk protein and 0.38 kg fat + protein over the first 3 lactations. The greatest benefit was when LWFC increased from 498 to 549 kg. Increasing LWFC from 549 to 595 kg did not significantly increase milk, milk fat and milk protein yields from the second to third lactation. The combined effects of AFC and LWFC indicated that to reduce the negative effects on production due to decreasing AFC, LWFC would have to increase by 7.2, 2.9 and 2.2 kg for each month decrease in AFC (for milk, fat and protein production, respectively). By the end of the third lactation, only 58 heifers remained in the herd. The number of heifers remaining within the 9 groups ranged from 4 to 10. Increasing LWFC while decreasing AFC reduced the chances of a heifer remaining in the herd but this may have been biased by the feeding regime imposed during lactation. Responses to increasing AFC decreased as the number of lactations increased, indicating that heifers calving at younger AFC produce similar amounts to their older herd-mates by the end of third lactation. Increasing LWFC from 498 to 549 kg had the greatest benefits for yield, indicating a possible maximum LWFC of 549 kg for our study. Therefore, the negative effects due to decreasing AFC can be offset in part, by increasing LWFC. However, on-farm resources and ultimately milk price will determine the choice of combination of AFC and LWFC.

Effects of Ionizable Residues on the Absorption Spectrum and Initial Electron-Transfer Kinetics in the Photosynthetic Reaction Center of Rhodobacter sphaeroides

Effects of ionizable amino acids on spectroscopic properties and electron-transfer kinetics in the photosynthetic reaction center (RC) of Rhodobacter sphaeroides are investigated by site-directed mutations designed to alter the electrostatic environment of the bacteriochlorophyll dimer that serves as the photochemical electron donor (P). Arginine residues at homologous positions in the L and M subunits (L135 and M164) are changed independently: Arg L135 is replaced by Lys, Leu, Glu, and Gln and Arg M164 by Leu and Glu. Asp L155 also is mutated to Asn, Tyr L164 to Phe, and Cys L247 to Lys and Asp. The mutations at L155, L164, and M164 have little effect on the absorption spectrum, whereas those at L135 and L247 shift the long-wavelength absorption band of P to higher energies. Fits to the ground-state absorption and hole-burned spectra indicate that the blue shift and increased width of the absorption band in the L135 mutants are due partly to changes in the distribution of energies for the zero-phonon absorption line and partly to stronger electron-phonon coupling. The initial electron-transfer kinetics are not changed significantly in most of the mutants, but the time constant increases from 3.0 +/- 0.2 in wild-type RCs to 4.7 +/- 0.2 in C(L247)D and 7.0 +/- 0.3 ps in C(L247)K. The effects of the mutations on the solvation free energies of the product of the initial electron-transfer reaction (P(+)) and the charge-transfer states that contribute to the absorption spectrum ( and ) were calculated by using a distance-dependent electrostatic screening factor. The results are qualitatively in accord with the view that electrostatic interactions of the bacteriochlorophylls with ionized residues of the protein are strongly screened and make only minor contributions to the energetics and dynamics of charge separation. However, the slowing of electron transfer in the Cys L247 mutants and the blue shift of the spectrum in some of the Arg L135 and Cys L247 mutants cannot be explained consistently by electrostatic interactions of the mutated residues with P and B(L); we ascribe these effects tentatively to structural changes caused by the mutations.

Application of TEPC microdosimetry to boron neutron capture therapy

Boron neutron capture therapy (BNCT) is a bimodal radiation therapy used primarily for highly malignant gliomas. Tissue-equivalent proportional counter (TEPC) microdosimetry has proven an ideal dosimetry technique for BNCT, facilitating accurate separation of the photon and neutron absorbed dose components, assessment of radiation quality and measurement of the BNC dose. A miniature dual-TEPC system has been constructed to facilitate microdosimetry measurements with excellent spatial resolution in high-flux clinical neutron capture therapy beams. A 10B-loaded TEPC allows direct measurement of the secondary charged particle spectrum resulting from the BNC reaction. A matching TEPC fabricated from brain-tissue-equivalent plastic allows evaluation of secondary charged particle spectra from photon and neutron interactions in normal brain tissue. Microdosimetric measurements performed in clinical BNCT beams using these novel miniature TEPCs are presented, and the advantages of this technique for such applications are discussed.

Reduction of enteric microorganisms at the Upper Occoquan Sewage Authority Water Reclamation Plant

The Upper Occoquan Sewage Authority (UOSA) Water Reclamation Plant, Centreville, Virginia, is a state-of-the-art wastewater treatment plant that was created to treat area wastewater and provide protection for the Occoquan Reservoir. This study investigated UOSA's unit processes as barriers to pathogenic as well as altemative and traditional-indicator microorganisms. Samples were collected once a month for 1 year from eight sites within UOSA's advanced wastewater reclamation plant. The eight sites were monitored for indicator bacteria total and fecal coliforms, enterococci, Clostridium, coliphage (the virus that infects Escherichia coli), human enteroviruses, and enteric protozoa. Overall, the plant was able to achieve a 5- to 7-log10 reduction of bacteria, 5-log10 reduction of enteroviruses, 4-log10 reduction for Clostridium, and 4.6-log10 reduction of protozoa. Total coliforms, enterococci, Clostridium, coliphage, Cryptosporidium, and Giardia were all detected in four or fewer samples of the final effluent. No enteroviruses or fecal coliforms were detected in the final effluent. The microbiological quality of reclaimed water and the reservoir water were compared. In every case, the treated wastewater was of a better quality than the ambient water in the reservoir, thus indicating that the reclaimed water will not adversely affect the water quality for downstream users.

A pilot survey of social work services in pediatric primary care programs in urban teaching hospitals

OBJECTIVE

To determine the current status of social work presence in pediatric primary care clinics in urban teaching hospitals.

DESIGN

Survey instrument mailed to the medical directors of outpatient pediatrics in the major pediatric teaching hospital of approved residency programs in the 100 largest metropolitan areas in the United States.

RESULTS

Sixty responses (60%) were received. Eighty percent of practices reported having on-site social work services, with a median of 14,805 annual clinic visits per social work full-time equivalent. Ninety-five percent of respondents considered on-site social work services in pediatric primary care to be important, whereas half of respondents considered social work services "less than adequate" at their site, and most of these felt this inadequacy had led to additional hospital visits or other adverse outcomes. There were no significant associations of reported adequacy of social work services with any characteristics of hospital, practice, or population.

CONCLUSION

Pediatric primary care clinicians at teaching hospitals consider on-site social work services to be important, but most report these services are less than adequate in their practices, and for many, adequacy has declined.

Developing a community-specific health-related quality of life (HRQOL) questionnaire for asthma: the Asthma-Specific Quality of Life Questionnaire for Native American Adults (AQLQ-NAA)

The Asthma Quality of Life Questionnaire for Native American Adults (AQLQ-NAA) was developed by modifying the Asthma Quality of Life Questionnaire-Marks (AQLQ-M) using the focus group technique. The 19-item AQLQ-NAA has emphasis on restrictions in social, community, and cultural activities. Higher scores indicate a better quality of life. The modified questionnaire was administered to a sample of 51 Native American adults with asthma at the Albuquerque USPHS Indian Hospital and its affiliated field clinics. Principal components analysis identified three domains with eigenvalues greater than 1.00: Community and Social Restrictions (CSR), Psychological Impact (PIM), and Symptoms (SYM). Cronbach's coefficient alpha for the AQLQ-NAA was 0.95 and ranged from 0.82 to 0.93 for the individual domains, indicating good internal consistency. The AQLQ-NAA score correlated negatively and significantly to urgent care visits, physician visits, and total number of medications taken for asthma in the past 6 and 12 months (p < 0.05). Additionally, the AQLQ-NAA score was correlated positively and significantly to medication adherence in the past 6 and 12 months (p < 0.05). Similar patterns of correlations were found with all three domain scores. These results indicated that there is evidence for the construct validity of the AQLQ-NAA and its domains. The AQLQ-NAA should provide a useful measure of HRQOL in asthma-specific medical interventions for the population in which it was developed.

Effects of age and liveweight at first calving on first lactation milk, protein and fat yield of Friesian heifers

This paper reports on both the individual and combined effects of age (AFC) and liveweight (LWFC) at first calving for Australian Holstein–Friesian heifers on first lactation production. One hundred and thirty-five Australian Holstein–Friesian heifers were allocated to 1 of 3 AFC treatments. Within each AFC treatment, heifers were randomly assigned to 1 of 3 LWFC treatments. Heifers in all groups grazed pasture and were supplemented when the quantity and quality of pasture was inadequate to meet growth requirements. Mean AFC and LWFC achieved were 25.1, 29.9 and 33.9 months and 498, 549 and 595 kg, respectively. Mean liveweight gains from 16 weeks of age to calving ranged from 0.45 to 0.71 kg/day, depending on treatment. The heifers calving at 33.9 months of age produced 6.6 and 12.3% more milk, 6.3 and 11.9% more protein and 5.4 and 12.2% more fat than those calving at 29.9 and 25.1 months of age at the end of their first 300 day lactation, respectively. The lower production of the younger cows was associated with decreased daily output rather than by shorter lactation length. Heifers averaging 595 kg at first calving produced 5.5% more milk, 8.4% more protein and 11.4% more fat than those averaging 498 kg in first lactation, respectively. The heifers averaging 621 kg LWFC and 34 months AFC had the highest production of the 9 treatment groups. Production was increased by 5.35 L milk, 0.19 kg protein and 0.23 kg fat for an additional 1 kg LWFC, respectively. For each month delay in AFC, production was increased by 66.7 L milk, 1.87 kg protein and 2.36 kg fat, respectively. The combined effects of AFC and LWFC showed that to offset the negative effects of a 1 month reduction in AFC on milk, protein and fat yields in first lactation, LWFC would have to be increased by 8.1, 4.0 and 4.5 kg, respectively. Under the conditions of this experiment, maximum milk, protein and fat were estimated to be achieved at 559, 563 and 568 kg liveweight at first calving, respectively.

Detection of viral pathogens by reverse transcriptase PCR and of microbial indicators by standard methods in the canals of the Florida Keys

In order to assess the microbial water quality in canal waters throughout the Florida Keys, a survey was conducted to determine the concentration of microbial fecal indicators and the presence of human pathogenic microorganisms. A total of 19 sites, including 17 canal sites and 2 nearshore water sites, were assayed for total coliforms, fecal coliforms, Escherichia coli, Clostridium perfringens, enterococci, coliphages, F-specific (F(+)) RNA coliphages, Giardia lamblia, Cryptosporidium parvum, and human enteric viruses (polioviruses, coxsackie A and B viruses, echoviruses, hepatitis A viruses, Norwalk viruses, and small round-structured viruses). Numbers of coliforms ranged from <1 to 1, 410, E. coli organisms from <1 to 130, Clostridium spp. from <1 to 520, and enterococci from <1 to 800 CFU/100 ml of sample. Two sites were positive for coliphages, but no F(+) phages were identified. The sites were ranked according to microbial water quality and compared to various water quality standards and guidelines. Seventy-nine percent of the sites were positive for the presence of enteroviruses by reverse transcriptase PCR (polioviruses, coxsackie A and B viruses, and echoviruses). Sixty-three percent of the sites were positive for the presence of hepatitis A viruses. Ten percent of the sites were positive for the presence of Norwalk viruses. Ninety-five percent of the sites were positive for at least one of the virus groups. These results indicate that the canals and nearshore waters throughout the Florida Keys are being impacted by human fecal material carrying human enteric viruses through current wastewater treatment strategies such as septic tanks. Exposure to canal waters through recreation and work may be contributing to human health risks.