A234 IN VITRO GUT MICROBIOME AND METABOLITE RESPONSES TO RESISTANT STARCH ARE INDIVIDUALIZED

Background

Gut microbes degrade and ferment resistant starch (RS) into metabolites that help maintain gut homeostasis. Clinical trials have evaluated RS for various health conditions, but individuals respond to RS with profound variability. The reason for this variability is unclear.

Aims

Using in vitro culturing methods and multi-omic analyses, we hypothesize that individuals will elicit variable responses to RS with respect to overall fermentation, bacterial composition, short chain acid production, and metabolite flux.

Methods

As part of an ongoing clinical trial, we have selected 4 pediatric patients with inflammatory bowel disease to better understand microbiome-RS interactions. We cultured stools anaerobically using a high-throughput platform (“RapidAIM”) with 9 different pre-digested RS. After 18-hour incubations, media supernatants were used to measure pH and perform targeted and semi-targeted metabolomic analyses with a panel of 116 compounds. Bacterial pellets were isolated for 16S rRNA gene sequencing analyses to evaluate changes in microbiome compositions. Data were analyzed with generalized linear mixed models, principal component analysis (PCA), random forest (RF) classification with feature selection, and network construction with graphical lasso.

Results

Changes in several microbiome parameters were different across individuals, including the magnitude of pH changes, metabolite signatures, and relative abundances of important bacterial taxa. Bacterial species known to degrade RS were more abundant in individuals showing stronger RS fermentation. Inter-individual discrimination was accomplished with PCA and RF, from which we could identify metabolite signatures. The robustness of microbiome networks corresponded to RS fermentation and butyrate production.

Conclusions

We report a novel perspective on how individuals respond to RS’ differently. Butyrate remains an important hub of the microbiome architecture with respect to RS fermentation. Future work will interrogate the roles of individualized metabolomic responses on host physiology. In vivo responses to RS are being evaluated in an ongoing clinical trial.

Funding Agencies

CCC, CIHRGenome Ontario, Genome Canada

The benefits of rural training: Producing the expert generalists of the future

Most doctors in the UK train in urban areas and tertiary centres are considered centres of excellence for training, with rural district general hospitals often seen as a training backwater. However, there are huge benefits to training in rural areas, particularly with an ageing population, increased medical complexity and a shift of care from hospitals to the community. This article examines the benefits of rural training and looks at its role in producing the 'expert generalists' of the future.

Association of Maternal Vitamin D Deficiency with Early Childhood Caries

Alaska Native (AN) children experience one of the highest reported rates of severe early childhood caries (S-ECC). Serum vitamin D concentrations in AN childbearing women in the Yukon Kuskokwim Delta (YKD) region have decreased since the 1960s to currently low levels, related to a decrease in traditional marine diet. Recent studies suggest an association between prenatal vitamin D (25(OH)D) concentrations in mothers and S-ECC in their infants. We used independent t tests to analyze the influence of prenatal 25(OH)D levels in YKD AN mothers on S-ECC in their children using data collected in the Maternal Organics Monitoring Study (MOMS). Maternal 25(OH)D levels were assessed at prenatal visits and in cord blood. We queried electronic dental records to assess early childhood caries (ECC) status using highest decayed, missing, filled, primary teeth (dmft) scores at 12 to 59 mo of age. We examined prenatal and cord blood for 76 and 57 mother/infant pairs, respectively. Children 12 to 35 mo of age with "deficient" cord blood (25(OH)D <30 nmol/L) had a mean dmft score twice as high as children who were "nondeficient" at birth (9.3 vs. 4.7; P = 0.002). There was no significant difference in mean dmft scores for children aged 36 to 59 mo with deficient versus nondeficient cord blood 25(OH)D (10.9 vs. 8.7 P = 0.14). There was no significant difference in mean dmft scores for children aged 12 to 35 mo whose mothers had "sufficient" versus "insufficient" 25(OH)D during prenatal visits (9.0 vs. 7.4; P = 0.48). In this small sample, children with deficient vitamin D levels in cord blood had a dmft score at 12 to 35 mo 2-fold higher than children with nondeficient cord blood. Maternal 25(OH)D may influence the primary dentition, and improving vitamin D status in pregnant women might affect ECC rates in their infants.

Housing characteristics and indoor air quality in households of Alaska Native children with chronic lung conditions

Alaska Native children experience high rates of respiratory infections and conditions. Household crowding, indoor smoke, lack of piped water, and poverty have been associated with respiratory infections. We describe the baseline household characteristics of children with severe or chronic lung disease participating in a 2012-2015 indoor air study. We monitored indoor PM2.5, CO2 , relative humidity %, temperature, and VOCs and interviewed caregivers about children's respiratory symptoms. We evaluated the association between reported children's respiratory symptoms and indoor air quality indicators using multiple logistic regression analysis. Compared with general US households, study households were more likely overcrowded 73% (62%-82%) vs 3.2% (3.1%-3.3%); had higher woodstove use as primary heat source 16% (9%-25%) vs 2.1% (2.0%-2.2%); and higher proportion of children in a household with a smoker 49% (38%-60%) vs 26.2% (25.5%-26.8%). Median PM2.5 was 33 μg/m3 . Median CO2 was 1401 ppm. VOCs were detectable in all homes. VOCs, smoker, primary wood heat, and PM2.5>25 μg/m3 were associated with higher risk for cough between colds; VOCs were associated with higher risk for wheeze between colds and asthma diagnosis. High indoor air pollutant levels were associated with respiratory symptoms in household children, likely related to overcrowding, poor ventilation, woodstove use, and tobacco smoke.

Addressing Perinatal Disparities in Urban Setting: Using Community Based Participatory Research

Striking racial disparities in infant mortality exist in the United States, with rates of infant death among African Americans (AA) nearly twice the national average. Community-based participatory research (CBPR) approaches have been successful in fostering collaborative relationships between communities and researchers focused on developing effective and sustainable interventions and programs targeting needs of the community. The current paper details use of the Perinatal Period of Risk (PPOR) model as a method to engage communities by identifying factors influencing racial disparities in infant mortality and examining changes in those factors over a ten year period.

Comparison of proteins from thermophilic and nonthermophilic sources in terms of structural parameters inferred from amino acid composition

The amino acid composition of 14 different proteins from thermophilic bacteria were compiled along with the amino acid compositions of 56 corresponding proteins from nonthermophilic sources. A comparison was made between proteins serving the same catalytic function, and significant differences in composition were noted for those proteins from thermophilic bacteria. However, no consistent pattern was evident and the differences were often small. The two data pools were treated as two distinct classes and a thermophilic versus non-thermophilic comparison of amino acid composition was made using the Student's t-test. Significant differences in composition were found for Asx (sum of Asp and Asn, if known), Ser, and Arg. Both classes of data have similar standard deviations for the mean of any single amino acid, suggesting a similar tolerance of variation in the two classes of proteins. This would argue against the hypothesis that thermophiles exhibit a greater frequency of errors in protein synthesis. The amino acid compositions were used to calculate structural parameters (% helix, % beta, % turn, hydrophobicity, and melting temperatures) for the two classes of proteins. Of these, only the predicted % beta content was significantly lower for proteins of thermophilic origin. No differences in hydrophobicity or predicted melting temperature were observed for the two classes of proteins. This study supports the hypothesis that while small differences may occur in the amino acid composition of thermophilic proteins, they are quite varied and often are very subtle.

Use of d-3He proton spectroscopy as a diagnostic of shell rho r in capsule implosion experiments with approximately 0.2 NIF scale high temperature Hohlraums at Omega

We present the calculations and preliminary results from experiments on the Omega laser facility using d-(3)He filled plastic capsule implosions in gold Hohlraums. These experiments aim to develop a technique to measure shell rho r and capsule unablated mass with proton spectroscopy and will be applied to future National Ignition Facility (NIF) experiments with ignition scale capsules. The Omega Hohlraums are 1900 microm length x 1200 microm diameter and have a 70% laser entrance hole. This is approximately a 0.2 NIF scale ignition Hohlraum and reaches temperatures of 265-275 eV similar to those during the peak of the NIF drive. These capsules can be used as a diagnostic of shell rho r, since the d-(3)He gas fill produces 14.7 MeV protons in the implosion, which escape through the shell and produce a proton spectrum that depends on the integrated rho r of the remaining shell mass. The neutron yield, proton yield, and spectra change with capsule shell thickness as the unablated mass or remaining capsule rho r changes. Proton stopping models are used to infer shell unablated mass and shell rho r from the proton spectra measured with different filter thicknesses. The experiment is well modeled with respect to Hohlraum energetics, neutron yields, and x-ray imploded core image size, but there are discrepancies between the observed and simulated proton spectra.

Modelling chorded prosthetic mitral valves using the immersed boundary method

The Immersed Boundary (IB) Method is an efficient method of modelling fluid structure interactions. However, it has two main limitations: ease of use and ability to model static loading. In this paper, the method is developed, so that it can efficiently and easily model any multileaflet elastic structure. The structure may include chordae, which attach to the leaflets and continue through the leaflet surfaces. In addition, an external surface pressure may be applied to the leaflets, thus enabling the deformations that arise under steady loads to be solved. This method is validated for a model of the native mitral valve under systolic loading and for a prosthetic aortic valve under static loading. It is then applied to a new chorded prosthetic mitral valve, housed in a cylindrical tube, subject to a physiological periodic fluid flow. Results are compared with those obtained by using the commercial package ANSYS as well as with experimental measurements. Qualitative agreements are obtained. There are some discrepancies due to the current IB method being unable to model bending and shear behaviour. In particular, the fibre structures of the new prosthetic valve model developed using the IB method may be prone to crimping. Further development of the IB method is necessary to include bending effects. This will improve the accuracy of both the dynamic and static analysis.

Experience with the prevention of invasive Haemophilus influenzae type b disease by vaccination in Alaska: the impact of persistent oropharyngeal carriage

OBJECTIVES

To report the epidemiology of invasive Haemophilus influenzae type b (Hib) disease in high-risk Alaska Native infants before and after universal infant Hib vaccination and evaluate an increase in invasive Hib disease in 1996 after changing Hib vaccine type.

STUDY DESIGN

Statewide laboratory surveillance for invasive Hib disease has been conducted since 1980. Three cross-sectional Hib carriage studies were conducted in 1997 and 1998.

RESULTS

The invasive Hib disease rate in Alaska Natives decreased from 332 cases per 100,000 children <5 years old in 1980-1991 to 17:100,000 in 1992-1995 but increased primarily in rural areas to 57.9:100,000 after a switch in Hib vaccine types. Carriage studies in 5 rural Alaska Native villages showed oropharyngeal Hib carriage as high as 9.3% in children aged 1 to 5 years; in contrast, carriage in urban Alaska Native children was <1%.

CONCLUSIONS

Although Hib disease has decreased in Alaska, the rate of Hib disease and carriage in rural Alaska Natives did not decrease to the same extent as in non-Natives and urban Alaska Natives. Use of polyribosylribitol phosphate-outer-membrane protein conjugate vaccine for the first vaccine dose is critical to disease control in this population with continued transmission in infants <6 months of age. The ability to eliminate Hib carriage and disease may be affected by population characteristics, vaccination coverage, and Hib vaccine type used. This may pose a challenge to global elimination of Hib.

Bronchiectasis in Alaska Native children: causes and clinical courses

Although bronchiectasis has become a rare condition in U.S. children, it is still commonly diagnosed in Alaska Native children in the Yukon Kuskokwim Delta. The prevalence of bronchiectasis has not decreased in persons born during the 1980s as compared with those born in the 1940s. We reviewed case histories of 46 children with bronchiectasis. We observed that recurrent pneumonia was the major preceding medical condition in 85% of patients. There was an association between the lobes affected by pneumonia and the lobes affected by bronchiectasis. Eight (17%) patients had surgical resection of involved lobes. We conclude that the continued high prevalence of bronchiectasis appears to be related to extremely high rates of infant and childhood pneumonia. Pediatr Pulmonol. 2000;29:182-187. Published 2000 Wiley-Liss, Inc.

From bacteriology to biochemistry: Albert Jan Kluyver and Chester Werkman at Iowa State

This essay explores connections between bacteriology and disciplinary evolution of biochemistry in this country during the 1930s. Many features of intermediary metabolism, a central component of biochemistry, originated as attempts to answer fundamental bacteriological questions. Thus, many bacteriologists altered their research programs to answer these questions. In doing so they changed their disciplinary focus from bacteriology to biochemistry. Chester Hamlin Werkman's (1893-1962) Iowa State career illustrates the research perspective that many bacteriologists adopted. As a junior faculty member in the Bacteriology Department in the late 1920s, Werkman faced a powerful professional dilemma: establishing a research identity that distinguished him from his colleagues with flourishing national and international reputations. His solution was to radically alter his research program from traditional bacteriology to a biochemistry program, which reflected the influence of the Dutch microbiologist/biochemist, Albert Jan Kluyver (1888-1956). Werkman was extremely successful in this career change. His laboratory made significant contributions to biochemistry, and Werkman achieved a notable degree of personal success. His career began in the shadow of his departmental bacteriological colleagues; within a decade he became the department's dominant research figure, as a biochemist. Werkman's personal success, however, had profound consequences for the disciplinary future of bacteriology at Iowa State.

The challenge of ongoing Haemophilus influenzae type B carriage and transmission in Alaska

Cases of invasive Haemophilus influenzae type b disease in Alaskan children quickly dropped 10-fold after widespread vaccination with a conjugate vaccine (PRP-OMP) began in 1991. However, reemergence of invasive disease in 1996-97 soon followed a change to a combination diphtheria-tetanus toxoid-pertussis/H. influenzae type b vaccine which incorporates a different conjugate vaccine (HbOC). Previously unrecognized persistence of H. influenzae type b carriage in rural Alaska, coupled with characteristics of the immune response to HbOC, are the likely explanations for disease reemergence. The current vaccine recommendation--PRP-OMP for the first dose, followed by HbOC to complete the vaccination series--appears to protect Alaskan infants even in the face of continuing carriage and transmission. Successful control of invasive H. influenzae type b disease in Alaskan children will require not only appropriate immunization, but also continuing surveillance for both disease and carriage, identification of factors associated with carriage, and investigation into the feasibility of using vaccination plus antimicrobial drugs to eliminate this pathogen.

RSV-associated hospitalizations in Alaska Native infants

PURPOSE

Retrospective reviews for 1986-1992 suggested that Alaska Native children experience high rates of respiratory syncytial virus (RSV)-associated hospitalization; however, the epidemiology of RSV infections has been poorly characterized.

METHODS

A prospective hospital-based surveillance study was undertaken to determine rates of RSV-associated hospitalization in Alaska Native children < 36 months from the Yukon-Kuskokwim Delta.

RESULTS

During the first study year, October 1993 to September 1994, there were 40 RSV cases (hospitalization rate, 53/1,000 infants < 1 year of age); however, during the second year, October 1994 to September 1995, there were 251 RSV cases (hospitalization rate, 294/1,000 infants). An unusually high proportion, 12%, of RSV cases were < 1 month of age. Disease severity was higher for children with a history of prematurity, heart, or lung disease (p = .001, X2 analysis). Of 255 cell cultures during 1994-1995, 190 were RSV-positive, 11 were positive for influenza, 4 for adenovirus, and 1 for parainfluenza. This study demonstrates wide seasonal variation in a population with an extremely high RSV hospitalization rate; increased disease severity associated with young age and pre-existing medical conditions; and co-circulation of RSV with other viruses.

Reemergence of invasive Haemophilus influenzae type b disease in a well-vaccinated population in remote Alaska

Before vaccination, Alaska Natives experienced very high rates of invasive Haemophilus influenzae type b (Hib) disease and carriage. Vaccination with Hib conjugate vaccine PRP-OMP (polyribosylribitol phosphate Neisseria meningitidis outer membrane protein) began in 1991 and resulted in a sharp decline in cases. In 1996, after switching to a different Hib conjugate vaccine, DTP-HbOC (which combines diphtheria-tetanus-whole cell pertussis vaccines with HbOC [Hib oligosaccharide CRM197]), cases of invasive Hib disease increased, suggesting ongoing Hib transmission despite widespread vaccination. To determine the prevalence of and risk factors for carriage, a cross-sectional study of oropharyngeal Hib carriage was conducted among Alaska Native children aged 1-5 years in remote southwestern Alaska. Of 496 children with swabs taken, 46 (9.3%) were colonized with Hib. Carriage rates varied by village from 2.2% to 13.2% and by age from 6.1% in 1-year-olds to 14.7% in 5-year-olds. Crowding was associated with Hib carriage. Widespread vaccination with PRP-OMP Hib conjugate vaccine did not eliminate carriage in this population of Alaska Natives, and ongoing carriage contributed to disease resurgence.

Robert Earle Buchanan: an unappreciated scientist

Robert Earle Buchanan (1883-1973), 19th President of the Society of American Bacteriologists (later American Society for Microbiology), was one of the more important 20th century microbiologists. He was a dominant force in creating the field of bacterial systematics and made significant contributions to microbial physiology. He also numbered a number of influential textbooks. A reasonable conclusion is that Buchanan was a major cultivator of modern microbiology. To justify that assertion, I have four major objectives in this essay: i) a brief biographical review of Buchanan's early life; ii) a brief review of his scientific contributions, many of which go beyond his recognized contributions to bacterial systematics; iii) Buchanan was an important academic administrator who created the microbiology program and fostered a strong graduate education program at Iowa State, iv)finally, I close the essay with a focus on Buchanan's "moral character."

Overuse of parenteral antibiotics for wound care in an urban emergency department

This study compared patterns of parenteral antibiotic treatment by emergency physicians with literature-derived guidelines in the management of wound care. All patients who received parenteral antibiotics as part of wound management in an urban general emergency department (ED) (annual volume 65,000) and did not receive subsequent consultation or admission were prospectively studied for 4 weeks (July 18 to August 15, 1994). Data collected included age, sex, antibiotic, route of administration, dose, cost, diagnosis, and board certification of emergency physician. Antibiotic choice and dose were reviewed by study-blinded physicians and compared with criteria based on a review of the current wound care literature. Wound characteristics justifying antibiotic prophylaxis were derived from the literature and included immunocompromised patient, wounds with debris or occurring under contaminated circumstances, wounds with cellulitis or purulent drainage, wounds older than 18 hours, and crush injuries. The study included 72 patients, and 13 (18%) antibiotic discrepancies were found. Cefazolin (n = 49 [64%]) and ceftriaxone (n = 25 [35%]) were the most commonly prescribed parenteral antibiotics, with cefazolin used in 9 (69%) and ceftriaxone in 4 (31%) of discrepant cases. There were not significant differences in discrepant parenteral antibiotic by emergency physicians' board certification. There were no significant demographic differences between patients receiving discrepant and nondiscrepant antibiotics. The excess cost of discrepant parenteral antibiotics during this small study period was $380. Approximately one fifth of the parenteral antibiotics prescribed during wound care administered in the ED were discrepant with current recommendations derived from the literature.

Correlation of thallium uptake with left ventricular wall thickness by cine magnetic resonance imaging in patients with acute and healed myocardial infarcts

Myocardial infarction (MI) is characterized by cellular necrosis which undergoes fibrotic transformation over time. Cine magnetic resonance imaging (MRI) offers high-resolution 3-dimensional images of the left ventricular myocardium, allowing sampling of the myocardial wall thickness over the entire left ventricle. Tomographic (single-photon emission computed tomography [SPECT]) thallium images also provide 3-dimensional information on the location and level of thallium uptake, which has been shown to correlate with myocardial viability. The purposes of this study were: (1) to examine the relation between both end-diastolic and end-systolic wall thickness and normalized thallium-201 uptake over the left ventricle in a group of patients with MI, (2) to examine the relation between regional wall thickening and normalized thallium uptake, and (3) to examine the relation between thallium uptake and wall thickness both early and late after infarction. Twenty-four patients with MI underwent stress, redistribution, and reinjection thallium SPECT imaging and cine MRI within several days. Seventeen patients underwent imaging late after infarction and 7 underwent imaging early after infarction. Normalized thallium activity was correlated with MRI wall thicknesses at both end-diastole and end-systole for 18 segments for each ventricle. In addition, end-diastolic and end-systolic wall thicknesses were grouped by their corresponding thallium activity levels into percentiles. End-systolic wall thickness correlated significantly with normalized thallium uptake in 14 of 18 segments, end-diastolic wall thickness in only 4 of 18 segments, and wall thickening in only 3 of 18 segments. Mean values for end-diastolic and end-systolic wall thicknesses corresponding to severely reduced (<50%) normalized thallium activity were 9.9 +/- 1.1 and 8.5 +/- 0.6, respectively. Using receiver-operating curve analysis, end-systolic wall performed as a better diagnostic parameter than end-diastolic wall for identifying severely reduced thallium activity levels. For all levels of thallium activity, end-diastolic wall thicknesses were all thinner late versus early after MI, whereas end-systolic wall thickness was thinner only in the segments corresponding to severely reduced thallium activity. Based on these results, end-systolic wall thickness is the best noninvasive anatomic parameter of myocardial scar.

The Australian Incident Monitoring Study. Problems with regional anaesthesia: an analysis of 2000 incident reports

There were 160 incidents associated with regional anaesthesia amongst the first 2000 incidents reported to the Australian Incident Monitoring Study. They were categorised into 6 groups; epidural anaesthesia (83), spinal anaesthesia (42), brachial plexus blocks (14), intravenous local anaesthesia (4), ocular blocks (3), and local infiltration (14). The largest single cause of incidents involved circulatory problems; these occurred in all the groups except brachial plexus block (30 cases of hypotension, 7 of arrhythmias, 3 of cardiac arrest, 2 of hypertension and 1 of myocardial ischaemia). There were 24 drug errors, of which 10 involved the "wrong drug" and 4 "inappropriate use". With the exception of these, all the remainder involved problems specific to regional anaesthesia: 26 inadvertent dural punctures; 19 failed or inadequate blocks; 14 dural puncture headaches (all cured by blood patches); 10 inadvertent total or high spinal blocks (of which 7 required artificial ventilation); 5 blocks on the wrong side or in the wrong patient; 3 late hypoxic incidents and a variety of miscellaneous problems. Three-quarters of all incidents occurred in the presence of an anaesthetist and over 90% in patients of ASA Groups I-III. Rapid recognition by the anaesthetist prevented many potentially life threatening events, and the only death was as a result of surgical bleeding.

Palliative home care program for terminally ill children

A study conducted for the Dr. Charles A. Janeway Child Health Centre, St. John's, Newfoundland, determined that pediatric oncology patients and their families had needs that were not being met by the existing program of care. The article describes those needs, and then outlines the multidisciplinary palliative home care program that was established by the health centre to address them. The program's procedures of operation and follow-up, and the evaluation process are discussed.

Ask the doctor: answers may surprise you

In summary, physicians tend to base their final decision not only on the combination and culmination of all of the information that they gain about the location and the practice opportunity, but it seems that the final decision is mainly based on a trust factor. This trust factor lies in the belief that comments the administrator may have made while walking the halls with the candidate were true. Many physicians comment that they decide to go to one location over the other when both are equally as impressive in terms of quality of life and quality of practice style, because they trusted and had a higher comfort level and established a rapport more quickly with one administration or medical staff over another.

Neuropathy in Navajo children: clinical and epidemiologic features

We describe a rare and apparently unique neuropathic syndrome among Navajo children living on the Navajo Reservation. Clinical features include sensorimotor neuropathy, corneal ulcerations, acral mutilation, poor weight gain, short stature, sexual infantilism, serious systemic infections, and liver derangement including Reye's syndrome-like episodes. Progressive CNS white matter lesions were diagnosed through magnetic resonance imaging. We identified 20 definite and 4 probable cases occurring between 1959 and 1986. Mean age at the time of 1st recognized symptom was 13 months (range, 1 month to 4 years 6 months). Ten individuals have died; 6 of the deaths occurred before 5 years of age. The incidence of this syndrome on the western Navajo reservation is 5 times higher than that on the eastern reservation (38 compared with 7 cases per 100,000 births). Although the etiology is unknown, this syndrome is consistent with an inborn error of metabolism, inherited in an autosomal recessive manner.

Effect of Calcium Cation on Plating Efficiency of the Sulfate-Reducing Bacterium Desulfovibrio vulgaris

The presence of Ca 2+ (concentration, ca. 0.4 mM) in the growth medium causes cells of Desulfovibrio vulgaris (Hildenborough) to aggregate, leading to a decrease in plating efficiency. When the Ca 2+ concentration in the medium was reduced 20-fold, cell aggregation did not occur and the plating efficiency increased from an initial value of 34% to a final value of 56%.

Long-term complications in a premature infant with tracheoesophageal fistula

This is a report of the short- and long-term complications in a premature infant with tracheoesophageal fistula, including those related to central venous alimentation, seizures, chylothorax, bronchopulmonary dysplasia, dental erosions, gastroesophageal reflux, pulmonary problems, and gall stones. It offers analyses of possible alternate methods and treatments, which may have provided a better course.

Multiple organ donation: its impact on the recovery of cadaver kidneys

Cyclosporin A not only has improved renal allograft survival but it also has caused a renewed interest in cardiac and hepatic transplantation. The South Texas Organ Bank was sensitive to the need for multiple organ donors and also concerned that the recovery of multiple organs could have a negative impact on the quantity or quality of kidneys recovered. From July 1983 through March 1985 cadaveric kidneys were obtained from 43 renal donors and multiple vital organs were obtained from 11 additional donors. There was no statistical difference between the renal and multiple organ donors in the incidence of renal contamination, post-transplant acute renal failure or renal discard rate (p greater than 0.3 in each comparison). No donor family rescinded permission for renal donation because other vital organs were requested. Urologists involved in cadaveric renal recovery are encouraged to view every cadaver donor as a potential multiple organ donor.

Preliminary observation of impaired water excretion in treated status asthmaticus

Patients in status asthmaticus often have elevated plasma antidiuretic hormone levels. To determine if children in status asthmaticus have impaired water excretion and an increased risk of developing significant hyponatremia when given a fluid challenge, five consecutive patients who showed moderate asthmatic symptoms after taking two doses of epinephrine hydrochloride were given a fluid challenge (20 mL/kg of 5% dextrose in 0.2% normal saline solution given intravenously over 30 minutes followed by maintenance fluids [1,500 mL/sq m/24 hr] for 50 minutes). Urine was collected at 20-minute intervals for measurement of free-water clearance and percent water-load excretion in 80 minutes. This protocol was repeated 24 to 48 hours later, after clinical improvement. None of the patients was hyponatremic during status asthmaticus before water loading. However, four of five patients were mildly hyponatremic (serum sodium level between 130 and 132 mEq/L) between status asthmaticus and after clinical improvement. These same four patients also became mildly hyponatremic after fluid challenge during status asthmaticus. Maximal free-water clearance and percent water load excretion in 80 minutes were significantly lower during status asthmaticus after fluid challenge compared with results obtained after water loading when the patients' conditions were clinically improved. We conclude that patients in status asthmaticus have impaired water excretion after water loading but with a small risk of significant hyponatremia; a patient remaining in status asthmaticus and given large volumes of hypotonic fluid over a prolonged period of time may be at higher risk for significant hyponatremia.

Cytochrome c3 from the sulfate-reducing anaerobe Desulfovibrio africanus Benghazi: antigenic properties

Antisera were prepared against cytochromes c3 from Desulfovibrio africanus, D. vulgaris, and D. salexigens. Cross-reactions were observed between antisera to D. vulgaris and D. africanus cytochromes and heterologous cytochromes c3. A weak cross-reaction with antisera against both D. vulgaris and D. africanus cytochromes and the acid form of the D. salexigens cytochrome was seen; the basic form did not react.

Cardiac myxoma

Ten patients with cardiac myxoma were reviewed. The ranged from 23 months to 60 years old. Echocardiography was the most helpful noninvasive diagnostic technique. The tumor was demonstrated by angiocardiography, left atrial myxomas frequently migrating to the left ventricle in diastole. Hemodynamically, left atrial myxomas were associated with moderately severe pulmonary hypertension and simulated mitral stenosis or insufficiency and right atrial myxomas, with right atrial hypertension. There were 7 myxomas in the left atrium, 2 in the right atrium, and 1 in the right ventricle. Eight patients underwent open-heart operation with removal of the myxoma, 1 had concomitant tricuspid valve replacement, and 1 had biopsy of the right ventricle only. The other patient was a Jehovah's Witness and refused operation. One patient died of cardiac arrest intraoperatively, and another died of a bilateral cerebral infarct. One patient had recurrence requiring reoperation. Postoperative hemodynamic and clinical improvement was more striking in patients with a left atrial myxoma presumably due to a normal mitral valve in contradistinction to the tricuspid valve.

Cytochrome c3 from the sulfate-reducing anaerobe Desulfovibrio africanus Benghazi: purification and properties

Cytochrome c3 was purified from Desulfovibrio africanus Benghazi by extraction with alkaline deoxyribonuclease, fractionation with ammonium sulfate, batch elution from carboxymethyl Sephadex followed by chromatography on the same resin, and gel filtration on Sephadex G-75. The preparation was judge homogeneous by a variety of criteria. The molecular weight was determined in an analytical ultracentrifuge, and values between 14,400 and 15,490 were obtained, depending upon the presumed value of partial specific volume. Gel filtration on a calibrated column of Sephadex G-75 gave a value of 14,900 daltons. The amino acid composition was very similar to that observed for the cytochrome from other species of Desulfovibrio, with the exception of increased levels of ThR and PhE. S-Carboxymethylation of the protein before and after heme removal by HgCl2 demonstrated eight Cys molecules involved in heme binding or four heme sites per molecule. Titration with sodium dithionite under N2 gave an electrochemical potential (E' 0) of -276 mV relative to the normal hydrogen electrode. Electrochemical titration of the cytochrome gave a Nernst plot with two linear regions with E' 0 values of -0.376 and -0.534 V. The spectra produced at various potentials exhibited shifts in isosbestic points upon reduction, suggesting changes in conformation during the reaction.

Analysis of left ventricular function from multiple gated acquisition cardiac blood pool imaging. Comparison to contrast angiography

Global ventricular function was evaluated by both multiple gated cardiac blood pool scans (MUGA) and contrast ventriculograms in a group of 17 patients with suspected coronary artery disease. The contrast ventriculograms were analyzed frame by frame to generate a volume versus time curve for each patient, while the tracer data were analyzed by two methods: 1) the standard method, in which the left ventricle is identified on the end-diastolic frame and the background corrected activity under the region of interest obtained from the entire cardiac cycle, and displayed as a time versus activity curve; and 2) by a semi-automatic method in which the computer applies a threshold detection program to define the ventricular borders, and activity in the chamber at each point in the cardiac cycle is defined after background correction. The tracer data in each patient were analyzed independently by four observers. The tracer data correlated with the contrast data on a point by point basis r = 0.87 for the standard method, and 0.93 for the semi-automatic technique. An F test of variance revealed the semi-automatic method superior to the standard approach (P less than 0.05).