Enhancement of the Triple Alpha Rate in a Hot Dense Medium

In a sufficiently hot and dense astrophysical environment the rate of the triple-alpha (3α) reaction can increase greatly over the value appropriate for helium burning stars owing to hadronically induced deexcitation of the Hoyle state. In this Letter we use a statistical model to evaluate the enhancement as a function of temperature and density. For a density of 10^{6}  g cm^{-3} enhancements can exceed a factor of 100. In high temperature or density situations, the enhanced 3α rate is a better estimate of this rate and should be used in these circumstances. We then examine the effect of these enhancements on production of ^{12}C in the neutrino wind following a supernova explosion and in an x-ray burster.

Observation of the Isovector Giant Monopole Resonance via the ^{28}Si(^{10}Be,^{10}B^{*}[1.74 MeV]) Reaction at 100 AMeV

The (^{10}Be,^{10}B^{*}[1.74  MeV]) charge-exchange reaction at 100  AMeV is presented as a new probe for isolating the isovector (ΔT=1) nonspin-transfer (ΔS=0) response of nuclei, with ^{28}Si being the first nucleus studied. By using a secondary ^{10}Be beam produced by fast fragmentation of ^{18}O nuclei at the NSCL Coupled Cyclotron Facility, applying the dispersion-matching technique with the S800 magnetic spectrometer to determine the excitation energy in ^{28}Al, and performing high-resolution γ-ray tracking with the Gamma-Ray Energy Tracking In-beam Nuclear Array (GRETINA) to identify the 1022-keV γ ray associated with the decay from the 1.74-MeV T=1 isobaric analog state in ^{10}B, a ΔS=0 excitation-energy spectrum in ^{28}Al was extracted. Monopole and dipole contributions were determined through a multipole-decomposition analysis, and the isovector giant dipole resonance and isovector giant monopole resonance (IVGMR) were identified. The results show that this probe is a powerful tool for studying the elusive IVGMR, which is of interest for performing stringent tests of modern density functional theories at high excitation energies and for constraining the bulk properties of nuclei and nuclear matter. The extracted distributions were compared with theoretical calculations based on the normal-modes formalism and the proton-neutron relativistic time-blocking approximation. Calculated cross sections based on these strengths underestimate the data by about a factor of 2, which likely indicates deficiencies in the reaction calculations based on the distorted wave Born approximation.

β+ Gamow-Teller transition strengths from 46Ti and stellar electron-capture rates

The Gamow-Teller strength in the β(+) direction to (46)Sc was extracted via the (46)Ti(t,(3)He + γ) reaction at 115  MeV/u. The γ-ray coincidences served to precisely measure the very weak Gamow-Teller transition to a final state at 991 keV. Although this transition is weak, it is crucial for accurately estimating electron-capture rates in astrophysical scenarios with relatively low stellar densities and temperatures, such as presupernova stellar evolution. Shell-model calculations with different effective interactions in the pf shell-model space do not reproduce the experimental Gamow-Teller strengths, which is likely due to sd-shell admixtures. Calculations in the quasiparticle random phase approximation that are often used in astrophysical simulations also fail to reproduce the experimental Gamow-Teller strength distribution, leading to strongly overestimated electron-capture rates. Because reliable theoretical predictions of Gamow-Teller strengths are important for providing astrophysical electron-capture reaction rates for a broad set of nuclei in the lower pf shell, we conclude that further theoretical improvements are required to match astrophysical needs.

Effective helium burning rates and the production of the neutrino nuclei

Effective values for the key helium burning reaction rates, triple-α and (12)C(α, γ)(16)O, are obtained by adjusting their strengths so as to obtain the best match with the solar abundance pattern of isotopes uniquely or predominately made in core-collapse supernovae. These effective rates are then used to determine the production of the neutrino isotopes. The use of effective rates considerably reduces the uncertainties in the production factors arising from uncertainties in the helium burning rates, and improves our ability to use the production of B11 to constrain the neutrino emission from supernovae.

Probing configuration mixing in 12Be with Gamow-Teller transition strengths

We present a novel technique for studying the quenching of shell gaps in exotic isotopes. The method is based on extracting Gamow-Teller (ΔL=0, ΔS=1) transition strengths [B(GT)] to low-lying states from charge-exchange reactions at intermediate beam energies. These Gamow-Teller strengths are very sensitive to configuration mixing between cross-shell orbitals, and this technique thus provides an important complement to other tools currently used to study cross-shell mixing. This work focuses on the N=8 shell gap. We populated the ground and 2.24 MeV 0+ states in 12Be using the 12B(1+) (7Li, 7Be) reaction at 80  MeV/u in inverse kinematics. Using the ground-state B(GT) value from β-decay measurements (0.184±0.007) as a calibration, the B(GT) for the transition to the second 0+ state was determined to be 0.214±0.051. Comparing the extracted Gamow-Teller strengths with shell-model calculations, it was determined that the wave functions of the first and second 0+ states in 12Be are composed of 25±5% and 60±5% (0s)4(0p)8 configurations, respectively.

Gamow-Teller transition strengths from 56Ni

A new technique to measure (p,n) charge-exchange reactions in inverse kinematics at intermediate energies on unstable isotopes was successfully developed and used to study the (56)Ni(p,n) reaction at 110 MeV/u. Gamow-Teller transition strengths from (56)Ni leading to (56)Cu were obtained and compared with shell-model predictions in the pf shell using the KB3G and GXPF1A interactions. The calculations with the GXPF1A interaction reproduce the experimental strength distribution much better than the calculations that employed the KB3G interaction, indicating deficiencies in the spin-orbit and proton-neutron residual potentials for the latter. The results are important for improving the description of electron-capture rates on nuclei in the iron region, which are important for modeling the late evolution of core-collapse and thermonuclear supernovae.

11B and constraints on neutrino oscillations and spectra from neutrino nucleosynthesis

We study the sensitivity to variations in the triple-alpha and 12C(α,γ)16O reaction rates, of the yield of the neutrino-process isotopes 7Li, 11B, 19F, 138La, and 180Ta in core-collapse supernovae. Compared to solar abundances, less than 15% of 7Li, about 25%-80% of 19F, and about half of 138La is produced in these stars. Over a range of ±2σ for each helium-burning rate, 11B is overproduced and the yield varies by an amount larger than the variation caused by the effects of neutrino oscillations. The total 11B yield, however, may eventually provide constraints on supernova neutrino spectra.

34P(7Li,7Be+γ) reaction at 100A MeV in inverse kinematics

We report on the first successful extraction of a β+ Gamow-Teller strength distribution from a radioactive isotope in an intermediate-energy charge-exchange experiment in inverse kinematics. The (7Li,7Be+γ(429  keV)) reaction at 100A  MeV was used to measure Gamow-Teller transition strengths from 34P to states in 34Si. The results show that little mixing occurs between sd and pf shell configurations for the low-lying 0+ and 2+ states even though 34Si neighbors the island of inversion and low-lying 2ℏω intruder states exist. Shell-model calculations in the sdpf model space are consistent with these findings.

Extraction of weak transition strengths via the (3He, t) reaction at 420 MeV

Differential cross sections for transitions of known weak strength were measured with the (3He, t) reaction at 420 MeV on targets of 12C, 13C, 18O, 26Mg, 58Ni, 60Ni, 90Zr, 118Sn, 120Sn, and 208Pb. Using these data, it is shown that the proportionalities between strengths and cross sections for this probe follow simple trends as a function of mass number. These trends can be used to confidently determine Gamow-Teller strength distributions in nuclei for which the proportionality cannot be calibrated via beta-decay strengths. Although theoretical calculations in the distorted-wave Born approximation overestimate the data, they allow one to understand the main experimental features and to predict deviations from the simple trends observed in some of the transitions.

S17(0) determined from the Coulomb breakup of 83 MeV /nucleon 8B

A kinematically complete measurement was made of the Coulomb dissociation of 8B nuclei on a Pb target at 83 MeV/nucleon. The cross section was measured at low relative energies in order to infer the astrophysical S factor for the 7Be(p,gamma)8B reaction. A first-order perturbation theory analysis including E1, E2, and M1 transitions was employed to extract the E1 strength relevant to neutrino-producing reactions in the solar interior. By fitting the measured cross section from E(rel) = 130 to 400 keV, we find S17(0) = 17.8(+1.4)(-1.2) eV b.

Minimization and management of wastes from biomedical research

Several committees were established by the National Association of Physicians for the Environment to investigate and report on various topics at the National Leadership Conference on Biomedical Research and the Environment held at the 1--2 November 1999 at the National Institutes of Health in Bethesda, Maryland. This is the report of the Committee on Minimization and Management of Wastes from Biomedical Research. Biomedical research facilities contribute a small fraction of the total amount of wastes generated in the United States, and the rate of generation appears to be decreasing. Significant reductions in generation of hazardous, radioactive, and mixed wastes have recently been reported, even at facilities with rapidly expanding research programs. Changes in the focus of research, improvements in laboratory techniques, and greater emphasis on waste minimization (volume and toxicity reduction) explain the declining trend in generation. The potential for uncontrolled releases of wastes from biomedical research facilities and adverse impacts on the general environment from these wastes appears to be low. Wastes are subject to numerous regulatory requirements and are contained and managed in a manner protective of the environment. Most biohazardous agents, chemicals, and radionuclides that find significant use in research are not likely to be persistent, bioaccumulative, or toxic if they are released. Today, the primary motivations for the ongoing efforts by facilities to improve minimization and management of wastes are regulatory compliance and avoidance of the high disposal costs and liabilities associated with generation of regulated wastes. The committee concluded that there was no evidence suggesting that the anticipated increases in biomedical research will significantly increase generation of hazardous wastes or have adverse impacts on the general environment. This conclusion assumes the positive, countervailing trends of enhanced pollution prevention efforts by facilities and reductions in waste generation resulting from improvements in research methods will continue.

Prebiotic synthesis of vitamin B6-type compounds

Heating a dilute solution of NH3 and glycoaldehyde gives a large family of pyridines substituted with the same functional groups as occur in the forms of vitamin B6. Thus, vitamin B6-like molecules could have been present on the early Earth and could have been available for catalysis of primitive transamination reactions. Ethanolamine and N-methylethanolamine are also formed as major products. These are choline-like molecules, the latter of which is apparently formed by a prebiotic methylation process.

Hemopericardium with cardiac tamponade after intravenous thrombolysis for acute myocardial infarction

This report presents 2 patients with hemopericardium and tamponade encountered among a group of 26 patients who had received intravenous thrombolytic therapy for acute myocardial infarction during an 8-month time span. Both responded promptly to pericardiocentesis and pericardial catheter drainage. It is suggested that this rarely reported complication has the potential of occurring more frequently with increasing use of thrombolytics followed by aggressive anticoagulant regimens.

The clinical value of computerized information services. A review of 98 randomized clinical trials

OBJECTIVE

To review all randomized clinical trials addressing the efficacy of clinical information systems and to determine the clinical settings, types of interventions, and effects studied.

DATA SOURCES

Extensive and systematic MEDLINE searches were conducted using a combination of medical subject headings (MeSH) and textword terms to collect trial reports. Manual searches of books and monographs as well as informal contacts were also used.

STUDY SELECTION

The eligibility criteria were (1) randomized controlled clinical trial, (2) computerized information intervention in the study group, and (3) effect measured on the process or outcome of care.

DATA EXTRACTION

Two research assistants independently abstracted from the selected reports the following structured information: trial sites, computerized interventions, effect variables, and outcomes. Three investigators evaluated the combined list of trial features for setting, intervention, and effect. The statistical analysis included an evaluation of agreement in developing classifications and an analysis of the ratio of positive trial outcomes.

DATA SYNTHESIS

Most information services were tested in outpatient care (82%), particularly in primary care (66%). The information intervention targeted the provider in 64% of the trials. The effect was primarily measured for the process of care (76%). Provider prompt/reminder, computer-assisted treatment planner, interactive patient education/therapy, and patient prompt/reminder were significantly successful interventions (sign test, P < .05).

CONCLUSIONS

Randomized clinical trials confirm that four generic information interventions are active ingredients of computer systems and can make a significant difference in family medicine (physician and patient reminders, treatment planner, and patient education). To manage care and improve quality, primary care computer systems should incorporate these effective information services.

Case-control study of risk factors for development of pleuropneumonia in horses

Risk factors for development of pleuropneumonia were determined by reviewing medical records of 45 horses with pleuropneumonia and 180 control horses examined between Jan 1, 1980 and Jan 1, 1990. Factors considered included age, breed, sex, occupation, transport farther than 500 miles within the previous week, racing within the previous 48 hours, viral respiratory tract infection or exposure to horses with viral respiratory tract disease within the previous 2 weeks, and vaccination against influenza or rhinopneumonitis within the previous 6 months. Results indicated that Thoroughbreds were at a greater risk of developing pleuropneumonia than were other horses, and Standardbreds were at a reduced risk. Transport farther than 500 miles and viral respiratory tract disease or exposure to horses with respiratory tract disease were determined to be risk factors for the development of pleuropneumonia.

Methods of randomized controlled clinical trials in health services research

The randomized controlled clinical trial is an increasingly used method in health services research. Analysis of methodology is needed to accelerate practical implementation of trial results, select trials for meta-analysis, and improve trial quality in health services research. The objectives of this study are to explore the methodology of health services research trials, create and validate a streamlined quality evaluation tool, and identify frequent quality defects and confounding effects on quality. The authors developed a quality questionnaire that contained 20 evaluation criteria for health services research trials. One hundred one trials from the Columbia Registry of Controlled Clinical Trials were evaluated using the new quality tool. The overall agreement between independent reviewers, Cohen's kappa, was 0.94 (+/- 0.01). Of a possible score of 100, the trials received an average score of 54.8 (+/- 12.5). Five evaluation criteria indicated significant quality deficiencies (sample size, description of case selection, data on possible adverse effects, analysis of secondary effect variables, and retrospective analysis). The quality of study characteristics was significantly weaker than the quality of reporting characteristics (P < 0.001). The total average scores of Medline-indexed journals were better than the non-Medline-indexed journals (P < 0.001). There was a positive correlation between the overall quality and year of publication (R = 0.21, P < 0.05). The authors conclude that the new quality evaluation tool leads to replicable results and there is an urgent need to improve several study characteristics of clinical trials. In comparison to drug trials, site selection, randomization, and blinding often require different approaches in health services research.

The Columbia Registry of Information and Utilization Management Trials

OBJECTIVE

T systematically locate, register, and abstract information used in comparing effects of various information services (computerized and noncomputerized) and utilization management interventions on the process and outcome of patient care.

DESIGN

Manual and electronic database searches located reports that met three main criteria: 1) randomized controlled trial; 2) information or utilization management intervention in the study group with no similar intervention in the control group; and 3) effect of the intervention on the process and/or outcome of patient care had been measured. Published reports were registered in the Columbia Registry.

RESULTS

Nearly 600 reports were collected from 24 countries and 189 different publications. Frequently tested interventions included patients or physician education, telephone follow-up, patient or physician reminders, and home care services. Frequently reported effect variables included hospitalization rate, length of stay, immunization rate, and mortality rate. Standardized formal tools were developed for the separation and abstraction of practical information and methodologic details from the collected trial reports.

CONCLUSIONS

The registry provides a new source of information for meta-analyses, traditional reviews, and executive summaries of quality improvement of health services. The streamlined knowledge engineering process of quality evaluation and abstraction of critical information can generate helpful information for practitioners and researchers simultaneously.

Change in pH of plaque and 10% carbamide peroxide solution during nightguard vital bleaching treatment

The purpose of this study was to evaluate in vivo changes in the pH of plaque and of a 10% carbamide peroxide solution occurring within the bleaching guard during a 2-hour nightguard vital bleaching procedure. Baseline pH values for plaque and the carbamide peroxide solution were established. A small hole was placed in the anterior interproximal region of the guard to allow placement of the pH electrode. The pH of the carbamide peroxide solution was measured at 5-minute intervals. After 2 hours, the guard was removed and pH of the plaque was remeasured. The procedure was repeated three times on each of four subjects. The mean baseline pH reading for plaque was 6.31 and mean final pH reading was 6.86. The difference was statistically significant. At initial placement of the carbamide peroxide-filled guard, the mean intraguard pH was 4.50 (range of 2.80 to 7.80). The mean peak intraguard pH of 8.06 (range of 7.30 to 8.43), which was significantly different from baseline, was obtained within 31 minutes. The pH of plaque, saliva, and a 10% carbamide peroxide bleaching solution within the guard increased significantly during bleaching and remained significantly elevated for the duration of the study (2 hours).

Advanced information support. Abstracting evidence from clinical practice research

Suzanne M. Austin, M.H.A., and E. Andrew Balas, M.D., Ph.D., of the Health Services Management Program at the University of Missouri-Columbia, present research on exchange of information in clinical practices. Their findings have led them to develop an integrated knowledge base aimed at enhancing cognition and supporting action rather than increasing confusion and indecision.

Interlocking intramedullary nailing of femoral-shaft fractures in adolescents: preliminary results and complications

Thirty-one femoral-shaft fractures in 30 patients were treated with interlocking intramedullary nails. The 19 boys and 11 girls ranged in age from 10 to 15 years (average age 12 + 3 years) at the time of injury. All fractures united, and the average leg-length discrepancy (comparing the injured to the uninjured extremity) was 0.51 cm. Two patients had overgrowth of > 2.5 cm; none had angular or rotational malunions. One patient developed asymptomatic segmental avascular necrosis of the femoral head, which was not seen on radiographs until 15 months after injury. All nails were removed at an average of 14 months after injury; no refracture or femoral neck fracture has since occurred. Intramedullary nailing is a reasonable alternative for the treatment of isolated femoral-shaft fractures in older adolescents and in younger adolescents with multiple trauma.

Paternal cyclophosphamide exposure causes decreased cell proliferation in cleavage-stage embryos

Exposure of the male germ cell to cyclophosphamide during spermatogenesis and sperm maturation can interfere with development of the embryo. When male rats were treated with a chronic low dose of cyclophosphamide for 4 wk there was a dramatic increase in early postimplantation loss in their progeny, characterized by implantation sites selectively lacking in embryonic tissues. The present study was designed to determine the earliest appearance of a paternal effect of cyclophosphamide treatment and to examine whether the embryonic lineage was selectively affected. Male Sprague-Dawley rats were orally dosed for 4-5 wk with saline or 6 mg/kg per day of cyclophosphamide; their progeny were obtained on Days 2, 2.5, 3, 4, and 4.5 of gestation. Paternal cyclophosphamide treatment had no effect on the mean number of embryos per pregnant female. However, as early as Day 3 of gestation, there was a significant decrease in cell number among the embryos sired by cyclophosphamide-treated males, increasing to a greater than 50% decrease in cell number by Day 4. The cell doubling time in embryos sired by treated males (16 h) was longer than that of controls (12 h). This decreased proliferation rate was confirmed by a dramatic decrease in the capacity of both Day 3 and Day 4 embryos sired by cyclophosphamide-treated males to incorporate [3H]thymidine over a 26-h culture period. Cytogenetic analysis in a limited number of blastomeres entering metaphase revealed no evidence of chromosomal abnormalities. Both the trophectoderm and the inner cell mass cells were proportionally decreased in Day 4.5 embryos sired by cyclophosphamide-treated males. Thus, paternal cyclophosphamide exposure affected both cell lineages in the conceptus as early as Day 3 of gestation.

Effect of physician reminders on preventive care: meta-analysis of randomized clinical trials

The objective of this study was to assess the clinical value of the physician reminder, an information intervention, in increasing compliance for selected preventive health care measures. Meta-analysis was used to combine the quantitative evidence from randomized controlled clinical trials meeting the eligibility criteria. The trials included in this meta-analysis were conducted in a family or internal medicine clinic. Physician reminders were used in the trials to influence utilization and compliance of preventive health care activities. The use of physician reminders for preventive health care activities resulted in a homogeneous effect for the subcategories of cervical cancer screening (test for heterogeneity X2(2) = 4.122, non-significant) and tetanus immunization (test for heterogeneity X2(2) = 3.139, non-significant). Similarly, the odds ratio from the combination of evidence from the three cervical cancer screening trials was significant (1.180, 95 percent CI: 1.020 to 1.339). The resulting odds ratio from the combination of evidence from the three tetanus immunization trials was significant (2.819, 95 percent CI: 2.664 to 2.975). The results of the meta-analyses for cervical cancer screening and tetanus immunizations indicate that physician reminders are an effective information intervention and can improve compliance for these two preventive health care procedures. Based on the results of this meta-analysis, further trials testing the effect of physician reminders on tetanus immunization would be unnecessary and probably unethical.

Mitral valve disease associated with long-term ergotamine use

A 43-year-old woman with symptoms and signs of congestive heart failure and intermittent claudication was found to have moderately severe mitral stenosis and regurgitation, as well as severe bilateral upper and lower extremity arterial occlusive disease. She had a history of migraine headaches and had abused ergotamine tartrate (Cafergot) chronically for more than 20 years. Only rare instances of valvular heart disease have been associated with chronic ergotamine toxicity, with the majority of previously reported cases based on auscultatory findings alone.

Quality evaluation of controlled clinical information service trials

Randomized controlled clinical trials are increasingly accepted as tools of computer technology assessment and, therefore, quality evaluation of trials has great theoretical and practical significance. The purpose of this study was to assist the design of evaluation studies and synthesis of published results by developing and validating an easy-to-use quality scoring method. The development of the new scoring system was based on the available quality evaluation methods and the analysis of 19 trial reports registered in the Columbia Registry of Controlled Clinical Information Service Trials. First critical aspects and afterwards the levels of quality were defined. In spite of the fact that all quality requirements were met by some trials, the average overall quality score was 52.6 (+/- 8.7) per cent. The minimum score was 37 and the maximum was 72 per cent. Data collection and site/sample definition were better in the good quality trials, but improvement in statistical analysis was erratic. The quality scoring method was validated by using another sample of 20 registered trials. While the number of published controlled clinical trials is increasing in medical informatics, the analysis was unable to demonstrate a significant positive correlation between the quality and year of publication.

Slope of serial glomerular filtration rate and the progression of diabetic glomerular disease

Glomerular function was evaluated longitudinally over a 24- to 48-month period in 18 patients with diabetic glomerular disease (DGD) manifested by proteinuria. GFR was determined by iothalamate clearance at 4-month intervals. The patients were divided into two groups: Group 1 (N = 9) had subnephrotic proteinuria and an initially normal GFR of 91 +/- 8 mL/min. Group 2 (N = 9) had nephrotic-range proteinuria, and initial GFR was reduced to 53 +/- 5 mL/min. Serial GFR fluctuated over time in Group 1, but no trend towards hypofiltration was evident. In contrast, GFR declined linearly in Group 2 at 1.1 +/- 0.3 mL/min per month. The transglomerular sieving of uncharged dextrans of graded size was analyzed and initially revealed a uniform reduction in glomerular pore density and an enhancement of shuntlike pores. Pore density was initially reduced by 80% and declined further after 24 months in nephrotic Group 2; corresponding pore density in subnephrotic Group 1 was reduced by half but remained constant. Renal biopsy of four members of Group 1 revealed a 22% prevalence of global glomerulosclerosis. Remaining open glomeruli exhibited hypertrophy, excessive extracellular matrix, and deformation of epithelial podocytes. The latter abnormality appeared to be the predominant determinant of lowered ultrafiltration capacity. It was inferred that trials of therapy to attenuate the progression of DGD should be initiated at a functional level similar to that in subnephrotic Group 1. Because GFR is unlikely to decline over a 2- to 4-yr period, it is suggested that such trials be extended for longer periods. Alternatively, morphometric analysis of serial renal biopsies may shorten the time needed to demonstrate effective renoprotection in DGD.

Community hospital experience with recombinant tissue plasminogen activator in acute myocardial infarction

Clinical features, outcomes, and hospital charges of 51 consecutive patients who had had acute myocardial infarction (MI) and who had received intravenous tissue plasminogen activator (TPA) at a community teaching hospital were reviewed retrospectively. The overall mortality rate was 22%, including four patients (8%) who had died of hemorrhagic complications, three of whom (6%) had had intracerebral hemorrhages. Despite similar mean ages and lengths of hospital stay, TPA patients had had significantly higher total hospital charges and ancillary charges than had had concurrent MI patients who had not received TPA (p less than 0.0001). In a community hospital setting, older patients may be at higher risk for intracranial hemorrhage when treated with TPA, especially in the presence of other risk factors.

Case report: metolazone-associated hypercalcemia and acute pancreatitis

Metolazone-induced acute pancreatitis and hypercalcemia are described in a 58-year-old woman with severe congestive cardiac failure. Her symptoms and laboratory abnormalities rapidly resolved upon discontinuation of metolazone. Both clinical and laboratory findings make other etiologies for the patient's pancreatitis extremely unlikely. The pathophysiology of thiazide-related hypercalcemia and pancreatitis is reviewed. To our knowledge, neither hypercalcemia nor the combination of acute pancreatitis with hypercalcemia has been reported previously in association with metolazone therapy, and the association of pancreatitis and metolazone has been noted previously only once.

Comparison of the efficacy of ivermectin, oxibendazole, and pyrantel pamoate against 28-day Parascaris equorum larvae in the intestine of pony foals

Sixteen helminth-free pony foals were inoculated with a mean (+/- SD) 2,000 (+/- 545.5) infective Parascaris equorum eggs (day 0). Foals were allocated to replicates of 4, and treatments within each replicate were assigned at random. Treatment administered on postinoculation day (PID) 28 included no treatment (control), 0.2 mg of ivermectin/kg of body weight, 10 mg of oxibendazole/kg, or 6.6 mg of pyrantel base (pamoate)/kg. Paste formulations of the anthelmintics were administered orally. The foals were euthanatized 14 days after treatment (PID 42) and examined for P equorum larvae in the small intestine. The mean +/- SD (and range) numbers of fourth-stage P equorum larvae recovered from nontreated foals and those treated with ivermectin, pyrantel, or oxibendazole were 1,603.8 +/- 1,026.8 (305 to 2,480), 29.3 +/- 55.8 (0 to 113), 413.0 +/- 568.1 (0 to 1,204), or 889.5 +/- 1,123.1 (1 to 2,345), respectively. Compared with the value for control (nontreated) foals, treatment with ivermectin, pyrantel, and oxibendazole was 98.2, 74.2, and 44.5% effective, respectively, when administered 28 days after experimentally induced infection with P equorum. Adverse reactions attributable to treatment were not observed.

Dosimetric estimates for clinical positron emission tomographic scanning after injection of [18F]-6-fluorodopamine

Positron emission tomographic (PET) scanning after systemic i.v. injection of fluorine-18-6-fluorodopamine ([18F]-6F-DA) is a method for visualizing and measuring regional sympathetic nervous system innervation and function. Based on results of preclinical studies of rats and dogs and on previous literature about the fate of injected tracer-labeled catecholamines, dosimetric estimates for clinical studies are presented here. After injection of 1 mCi of [18F]-F-DA, the radiation dose would be highest to the wall of the urinary bladder (1.40 rem/mCi), due to accumulation of radioactive metabolites of [18F]-F-DA in urine. Radioactivity also would accumulate in bile. Organs receiving the next highest dose would be the kidneys (0.9 rem/mCi) and small intestine (0.2 rem/mCi). The parenchymal radiation dose would be lowest in the brain, since there is an effective blood-brain barrier for circulating catecholamines. Radiation doses to all organs after administration of 1 mCi of [18F]-F-DA to humans would be less than 3 rem and, therefore, within current FDA guidelines.

Serologic evidence of acute murine typhus infection in a patient with culture-negative endocarditis

A patient with culture-negative infective endocarditis is presented in whom detailed serological studies were indicative of acute infection with murine typhus. The patient had aortic and mitral regurgitation with congestive heart failure and typical peripheral manifestations of subacute endocarditis, but no documented fever. Aortic and mitral valve replacement surgery and a 6-week course of doxycycline therapy produced a clinical cure in this patient, as well as a diagnostic fall in markedly elevated preoperative typhus indirect fluorescent antibody (IFA) and complement fixation (CF) titers. Serological studies were consistently negative for Q fever.