Suppression of α-Cyano-4-hydroxycinnamic Acid Matrix Clusters and Reduction of Chemical Noise in MALDI-TOF Mass Spectrometry

Progress in high-throughput MALDI-TOFMS analysis, especially in proteome applications, requires development of practical and efficient procedures for the preparation of proteins and peptides in a form suitable for high acquisition rates. These methods should improve successful identification of peptides, which depends on the signal intensity and the absence of interfering signals. Contamination of MALDI samples with alkali salts results in reduced MALDI peptide sensitivity and causes matrix cluster formation (widely reported for CHCA matrix) observed as signals dominating in the range below m/z 1200 in MALDI spectra. One way to remove these background signals, especially for concentrations of peptides lower than 10 fmol/microL, is to wash matrix/sample spots after peptide cocrystallization on the MALDI plate with deionized water prior to analysis. This method takes advantage of the low water solubility of the CHCA compared to its alkali salts. We report here that the application of some ammonium salt solutions, such as citrates and phosphates, instead of deionized water greatly improves the efficiency of this washing approach. Another way to reduce matrix cluster formation is to add ammonium salts as a part of the MALDI matrix. The best results were obtained with monoammonium phosphate, which successfully suppressed matrix clusters and improved sensitivity. Combining both of these approaches-the addition of ammonium salts in the CHCA matrix followed by one postcrystallization washing step with ammonium buffer-provided a substantial ( approximately 3-5-fold) improvement in the sensitivity of MALDI-MS detection compared to unwashed sample spots. This sample preparation method resulted in improved spectral quality and was essential for successful database searching for subnanomolar concentrations of protein digests.

Factors affecting conjugated linoleic acid and trans-C18:1 fatty acid production by mixed ruminal bacteria

The objective of this study was to identify environmental factors that influence conjugated linoleic acid (CLA) and trans-C18:1 fatty acid production by mixed ruminal bacteria. Ruminal contents were collected from a 600-kg ruminally fistulated Hereford steer maintained on pasture. Mixed ruminal bacteria were obtained by differential centrifugation under anaerobic conditions and added to a basal medium that contained a commercial emulsified preparation of soybean oil and a mixture of soluble carbohydrates (cellobiose, glucose, maltose, and xylose). Culture samples were collected from batch culture incubations at 0, 2, 4, 6, 8, 12, 24, 26, 28, 30, 32, and 48 h. Continuous culture incubations were conducted at dilution rates of 0.05 and 0.10 h(-1) with extracellular pH values of 5.5 and 6.5, and 0.5 and 1.0 g/L of mixed soluble carbohydrates. Culture samples were obtained from the culture vessel once steady-state conditions had been achieved. In batch culture, trans-C18:1 concentrations increased over time and reached a maximum at 48 h. Little CLA was produced during the first 8 h, but cis-9, trans-11 CLA concentrations remained high between 24 and 30 h. When mixed ruminal bacteria were maintained in continuous culture on 0.5 g/L of mixed soluble carbohydrates, concentrations of trans-C18:1 and cis-9, trans-11 CLA were reduced (P < 0.05) at a dilution rate of 0.05 h(-1) and an extracellular pH of 5.5. Similar effects were also observed when 1.0 g/L of mixed soluble carbohydrates was used. When extracellular pH was lowered to 5.0, neither trans-C18:1 or CLA isomers were detected. In conclusion, our results suggest that culture pH appears to have the most influence on the production of trans-C18:1 and CLA isomers by mixed ruminal bacteria.

Effects of Saccharomyces cerevisiae culture and Saccharomyces cerevisiae live cells on in vitro mixed ruminal microorganism fermentation

The objective of this study was to examine the effects of a Saccharomyces cerevisiae live cell product and a S. cerevisiae culture product on the in vitro mixed ruminal microorganism fermentation of ground corn, soluble starch, alfalfa hay, and Coastal bermudagrass hay. In the presence of ground corn, neither concentration (0.35 or 0.73 g/L) of S. cerevisiae culture nor live cells had any effect on final pH, H2, CH4, propionate, or butyrate. The S. cerevisiae culture had no effect on acetate, but both concentrations of S. cerevisiae live cells decreased acetate and the acetate:propionate ratio. When soluble starch was the substrate, both concentrations of S. cerevisiae live cells and 0.73 g/L of S. cerevisiae culture decreased the acetate:propionate ratio. Although the treatment effects were not statistically significant, both concentrations of live cells and 0.73 g/L of the culture decreased lactate concentrations compared with the control incubations. When alfalfa hay served as the substrate, neither the S. cerevisiae culture nor the live cells had an effect on propionate, butyrate, or the acetate:propionate ratio. Both concentrations of S. cerevisiae culture decreased the final pH and in vitro dry matter disappearance, and the 0.73 g/L treatment decreased the amount of acetate. However, both treatments of S. cerevisiae live cells increased final pH and decreased acetate and in vitro dry matter disappearance. Neither yeast treatment had much effect on the Coastal bermudagrass hay fermentations. In general, both S. cerevisiae supplements seemed to have similar effects on the mixed ruminal microorganism fermentation.

Juxtaglomerular cell tumor: a clinicopathologic study of four cases and review of the literature

We studied 4 new cases of juxtaglomerular cell tumor and compared their morphologic and immunohistochemicalfeatures with 2 renal hemangiopericytomas and 5 cutaneous glomus tumors. The juxtaglomerular tumors were resectedfrom 2 males and 2 females (mean age at diagnosis, 23 years). Three patients manifested with severe hypertension. Tumors ranged from 2.2 to 8.0 cm and were well circumscribed. The tumors consisted of solid sheets and nodules of variably sized tumor cells with round, oval, and spindled nuclei alternating with edematous microcystic foci. Nuclear atypia, present in all tumors, was a prominent feature in 2. Mitotic activity was not identified. All cases showed hemorrhage, numerous mast cells, and thick-walled blood vessels. Unusual features included coagulative tumor necrosis, a hemangiopericytoma-like vascular pattern, and hyalinized stroma. All tumors were immunoreactive for CD34 and actin. Ultrastructural analysis revealed the presence of rhomboid-shaped renin protogranules. Patients were treated by partial or radical nephrectomy and followed up for 14 to 48 months. There were no recurrences or metastases. The characteristic clinical and morphologic features of juxtaglomerular cell tumor permit distinction from renal hemangiopericytoma and other renal tumors.

The physiological effects and metabolic alterations caused by the expression of Rhizobium etli pyruvate carboxylase in Escherichia coli

Oxaloacetate (OAA) plays an important role in the tricarboxylic acid cycle and for the biosynthesis of a variety of cellular compounds. Some microorganisms, such as Rhizobium etli and Corynebacterium glutamicum, are able to synthesize OAA during growth on glucose via either of the enzymes pyruvate carboxylase (PYC) or phosphoenolpyruvate carboxylase (PPC). Other microorganisms, including Escherichia coli, synthesize OAA during growth on glucose only via PPC because they lack PYC. In this study we have examined the effect that the R. etli PYC has on the physiology of E. coli. The expressed R. etli PYC was biotinylated by the native biotin holoenzyme synthase of E. coli and displayed kinetic properties similar to those reported for alpha4 PYC enzymes from other sources. R. etli PYC was able to restore the growth of an E. coli ppc null mutant in minimal glucose medium, and PYC expression caused increased carbon flow towards OAA in wild-type E. coli cells without affecting the glucose uptake rate or the growth rate. During aerobic glucose metabolism, expression of PYC resulted in a 56% increase in biomass yield and a 43% decrease in acetate yield. During anaerobic glucose metabolism, expression of PYC caused a 2.7-fold increase in succinate concentration, making it the major product by mass. The increase in succinate came mainly at the expense of lactate formation. However, in a mutant lacking lactate dehydrogenase activity, expression of PYC resulted in only a 1.7-fold increase in succinate concentration. The decreased enhancement of succinate formation in the /dh mutant was hypothesized to be due to accumulation of pyruvate and NADH, metabolites that affect the interconversion of the active and inactive form of the enzyme pyruvate formate-lyase.

A survey of genes in the Atlantic salmon (Salmo salar) as identified by expressed sequence tags

We describe the construction and quality analysis of six cDNA libraries from the liver, ovary, testis, brain, spleen and muscle tissues of adult Atlantic salmon. The cDNA libraries were then screened with total cDNA probes to catalogue clones representing the abundant and rare mRNA populations in each tissue. Subsequently, the 5'-terminal DNA sequences of 1152 cDNA clones, composed of 96 clones from each of the abundant and rare mRNA populations in the six tissues, were determined. Bioinformatic analysis revealed that 510 (50%) of the salmon expressed sequence tags (ESTs) of sufficient length showed significant homology to previously identified genes from salmonid and other species, while 517 (50%) of salmon ESTs were unidentified or novel. After accounting for multi-EST redundancy, the 510 identified ESTs provided DNA sequence markers for 178 salmon genes which are listed in terms of tissue of origin and mRNA abundance class.

In vitro mixed ruminal microorganism fermentation of whole cottonseed coated with gelatinized corn starch and urea

We conducted an in vitro mixed ruminal microorganism fermentation study to determine the effect of coating whole cottonseed with gelatinized corn starch and feed grade urea. Treatments were arranged as a 3 x 4 factorial to provide three concentrations of starch (0.0, 2.5, and 5.0%) and four concentrations of urea (0.0, 0.25, 0.5, and 1.0%). All treatments were prepared from one lot of whole cottonseed. Batch culture fermentations were conducted using anaerobic medium that contained 20% (vol/vol) ruminal fluid in 160-ml serum bottles. Whole cottonseed was ground to pass through a 6-mm screen and weighed amounts (0, 0.4, 0.8, and 1.2 g) were added to the serum bottles. As starch increased, H2, CH4, total volatile fatty acids, and molar proportions of propionate increased linearly, whereas pH, molar proportions of acetate, and the acetate to propionate ratio decreased linearly. L-Lactate concentrations were highest with 2.5% starch compared with 0 or 5.0%. As the amount of urea in the coating increased, pH and CH4 increased linearly, whereas H2 concentrations decreased linearly. Ammonia concentrations exhibited a quadratic response due to moderate increases with the addition of 0.25 and 0.5% urea, and a greater increase was observed with 1.0% urea. Interactions between starch and urea were observed for H2, CH4, NH3, and L-lactate. Concentrations of H2 decreased and CH4 was relatively constant as urea increased in the presence of 0 and 2.5% starch, but increased with 5% starch. L-Lactate concentrations were unchanged (0% starch), higher (2.5% starch), or lower (5.0% starch) as urea increased. Ammonia concentrations increased after urea exceeded 10% of the starch concentration. The addition of urea did not prevent the decline in pH, but did reduce H2 and CH4 accumulation with 2.5% starch.

Effect of student ethnicity on interpersonal skills and objective standardized clinical examination scores

OBJECTIVE

To determine whether standardized patients' perceptions of medical students' ethnicity influenced ratings on the interpersonal skills subsection of the objective standardized clinical examination (OSCE) and performance overall on the OSCE.

METHODS

The OSCE is used to evaluate medical students' performances in the obstetrics and gynecology basic clerkship at the Johns Hopkins University School of Medicine. It is based on a series of standardized patient interviews conducted by medical students and incorporates ratings by standardized patients on each student's interpersonal skills. Medical students (n = 353) enrolled in the obstetrics and gynecology basic clerkship from 1995-1998 were classified according to ethnicity. Overall OSCE scores according to ethnicity were analyzed using one-way analysis of variance. Total interpersonal skills scores and scores on the individual components of the interpersonal skills section of the OSCE were analyzed according to students' ethnicity using the Kruskal-Wallis test for nonparametric analysis of variance.

RESULTS

There were no statistically significant differences among ethnic groups in overall OSCE scores, total interpersonal skills scores, or scores on the individual components of the interpersonal skills section of the OSCE.

CONCLUSION

No bias attributable to perceived medical student ethnicity that affects performance on the OSCE exists.

Cloning and characterization of the rainbow trout (Oncorhynchus mykiss) type II interleukin-1 receptor cDNA

A homologue of mammalian type II interleukin-1 receptor (IL-1RII) was isolated from a rainbow trout cDNA library by differential hybridization using a suppression subtractive hybridization generated probe enriched for sequences upregulated after immune stimulation. The trout cDNA has an ORF encoding 441 amino acids, and represents the first piscine IL-1 receptor described. The predicted amino-acid sequence has 29 and 26% identity with human and mouse IL-1RII, respectively. The trout IL-1 receptor has a domain organization similar to that of mammalian type II receptor, with a short cytoplasmic tail of 24 amino acids. These results suggest that type II receptor is also present in lower vertebrates, and therefore the duplication of an ancestral gene that generated type I and type II IL-1 receptors occurred prior to the time mammals emerged.

Effects of diet on rumen proliferation and fecal shedding of Escherichia coil O157:H7 in calves

Calves inoculated with Escherichia coli O157:H7 and fed either a high-roughage or high-concentrate diet were evaluated for rumen proliferation and fecal shedding of E. coli O157:H7. Calves fed the high-roughage diet had lower mean rumen volatile fatty acid concentrations and higher rumen pH values than did calves fed the high-concentrate diet. Despite these differences in rumen conditions, the calves fed the high-roughage diet did not have greater rumen populations of E. coli O157: H7 and did not exhibit increased or longer fecal shedding compared with the calves fed the high-concentrate diet. Two calves shedding the highest mean concentrations of E. coli O157:H7 were both fed the high-concentrate diet. There was a significant (P < 0.05) positive correlation between fecal shedding and rumen volatile fatty acid concentration in calves fed a high-concentrate diet. The effects of diet on E. coli O157:H7 proliferation and acid resistance were investigated using an in vitro rumen fermentation system. Rumen fluid collected from steers fed a high-roughage diet, but not from steers fed a high-concentrate diet, supported the proliferation of E. coli O157:H7. Rumen fluid from steers fed a high-concentrate diet rapidly induced acid resistance in E. coli O157:H7. The impact of diet on fecal shedding of E. coli O157:H7 is still unclear and may depend on dietary effects on fermentation in the colon and on diet-induced changes in the resident microflora. However, rapid development of acid tolerance by E. coli O157:H7 in the rumens of calves fed high-concentrate diets, allowing larger populations to survive passage through the acidic abomasum to proliferate in the colon, may be one factor that influences fecal shedding in cattle on feed.

Effects of thymol on ruminal microorganisms

Thymol (5-methyl-2-isopropylphenol) is a phenolic compound that is used to inhibit oral bacteria. Because little is known regarding the effects of this compound on ruminal microorganisms, the objective of this study was to determine the effects of thymol on growth and lactate production by the ruminal bacteria Streptococcus bovis JB1 and Selenomonas ruminantium HD4. In addition, the effect of thymol on the in vitro fermentation of glucose by mixed ruminal microorganisms was investigated. Neither 45 nor 90 microg/ml of thymol had any significant effect on growth or lactate production by S. bovis JB1, but 180 microg/ml of thymol completely inhibited growth and lactate production. In the case of S. ruminantium HD4, 45 microg/ml of thymol had little effect on growth and lactate production; however, 90 microg/ml of thymol completely inhibited growth of S. ruminantium HD4. Thymol also decreased glucose uptake by whole cells of both bacteria. When mixed ruminal microorganisms were incubated in medium that contained glucose, 400 microg/ml of thymol increased final pH and the acetate to propionate ratio and decreased concentrations of methane, acetate, propionate, and lactate. In conclusion, thymol was a potent inhibitor of glucose fermentation by S. bovis JB1 and S. ruminantium HD4. Even though thymol treatment decreased methane and lactate concentrations and increased final pH in mixed ruminal microorganism fermentations of glucose, concentrations of acetate and propionate were also reduced.

Effect of sugars and malate on ruminal microorganisms

The objective of this study was to examine the effects of a commercial feed supplement that contains sugars and malate on lactate fermentation by Selenomonas ruminantium grown in batch culture. Experiments also were conducted to examine the effects of this feed supplement on the mixed ruminal microorganism fermentation of ground corn and soluble starch in the presence and absence of 5 mg/kg of monensin. When S. ruminantium strains HD4 and H18 were incubated in basal medium that contained DL-lactate, some DL-lactate was utilized by both strains after 24 h. In the presence of 1 g/L of sugars plus malate commercial feed supplement, both strains used most of the carbohydrate associated with the feed supplement between 6 and 8 h, and lactate was the main end product. In ground corn fermentations by mixed ruminal microorganisms, 2.25 and 3.25 g/L of sugars plus malate commercial feed supplement increased concentrations of acetate, propionate, and total volatile fatty acids, while 3.25 g/L increased lactate and decreased final pH and butyrate. Fermentation of soluble starch in the presence of both concentrations of sugars plus malate commercial feed supplement increased concentrations of acetate, propionate, and total volatile fatty acids and decreased the acetate:propionate ratio. In the presence of 5 mg/kg of monensin, sugars plus malate treatment increased concentrations of propionate and total volatile fatty acids in ground corn and soluble starch fermentations. Collectively, these results suggest that the sugars plus malate commercial feed supplement stimulates the ruminal fermentation.

Deoxyribonuclease activity in Selenomonas ruminantium, Streptococcus bovis, and Bacteroides ovatus

Six Selenomonas ruminantium strains (132c, JW13, SRK1, 179f, 5521c1, and 5934e), Streptococcus bovis JB1, and Bacteroides ovatus V975 were examined for nuclease activity as well as the ability to utilize nucleic acids, ribose, and 2-deoxyribose. Nuclease activity was detected in sonicated cells and culture supernatants for all bacteria except S. ruminantium JW13 and 179f sonicated cells. S. ruminantium strains were able to utilize several deoxyribonucleosides, while S. bovis JB1 and B. ovatus V975 showed little or no growth on all deoxyribonucleosides. When S. ruminantium strains 5934e, 132c, JW13, and SRK1 were incubated in medium that contained 15 mm ribose, the major end products were acetate, propionate, and lactate. S. ruminantium 5521c1 and S. bovis JB1 did not grow on ribose, and none of the S. ruminantium strains or S. bovis JB1 grew on 15 mm 2-deoxyribose. In contrast, B. ovatus V975 was able to grow on ribose and 2-deoxyribose. In conclusion, all S. ruminantium strains, S. bovis JB1, and B. ovatus V975 had nuclease activity. However, not all bacteria were able to utilize deoxyribonucleosides, ribose, or 2-deoxyribose.

Factors affecting glucose and maltose phosphorylation by the ruminal bacterium Megasphaera elsdenii

The objectives of this study were to examine the effects of growth substrate and extracellular pH on phosphoenolpyruvate-dependent glucose phosphorylation as well as to examine how maltose is phosphorylated by the ruminal bacterium Megasphaera elsdenii B159. Phosphoenolpyruvate-dependent glucose phosphorylation by toluene-treated cells was constitutive, and glucose phosphorylation was reduced by 69% at pH 5.0. When toluene-treated cells were incubated in histidine buffer, little maltose phosphorylation occurred in the absence of inorganic phosphate. However, the addition of increasing concentrations of either potassium or sodium phosphate increased maltose phosphorylation. Maximal phosphorylation activity was observed at between 25 and 50 mM of either inorganic phosphate source. Compared with the control incubations, maltose phosphorylation was increased over threefold with 25 mM of either potassium or sodium phosphate. Phosphoglucomutase activity was detected in cell extracts of M. elsdenii B159, and this enzyme had a K(m) of 3.2 mM for glucose-1-P and a V(max) of 1836 nmol of NADP(+) reduced/mg of protein per min. Maltose was also hydrolyzed by an inducible maltase (K(m), 1.19 mM). To our knowledge, this is the first report of a maltose phosphorylase and a maltase in M. elsdenii.

Impact of environmental inequity on health outcome: where is the epidemiological evidence?

A significant amount of evidence reveals a presence of environmental inequity. Although there is a disproportionate distribution of waste treatment, storage and disposal facilities, and chemical and manufacturing plants in minority and low-income communities in the United States, little research has been devoted to show any associations based on analytic epidemiological methods. To date, attempts to quantify health disparities have included demographic data, race, sex, income, other socioeconomic factors, and broad symptomatic survey instruments. To study this, we examined the latest epidemiological evidence documenting the existence of adverse health impacts resulting from environmental inequity. We observed that the overwhelming majority of studies were descriptive in nature and lacked comparison populations. As a result, we believe that further research based on analytic epidemiological methods would further contribute to the determination of the cause-effect relationship between environmental exposure and health outcome.

Anticoagulation clinics and patient self-testing for patients on chronic warfarin therapy: A cost-effectiveness analysis

This study was intended to evaluate the cost-effectiveness of anticoagulation clinic care and self-testing for the management of patients on chronic warfarin therapy. Using a 5-year Markov model, we evaluated the health and economic outcomes associated with each of three different anticoagulation management approaches: (1) usual care, (2) anticoagulation clinic testing with a capillary monitor, and (3) patient self-testing with a capillary monitor. Data available in the published literature and data from a large health system were used to develop model assumptions. Model results indicate that over a 5-year period, compared with usual care, anticoagulation clinic testing results in a total of 1.7 fewer thromboembolic events and 2.0 less hemorrhagic events per 100 patients. Another 4.0 thromboembolic events and 0.8 hemorrhagic events are avoided with patient self-testing compared with anticoagulation clinic testing. In addition to the health advantages of these strategies, both also have cost advantages. When the costs incurred by provider organizations and patients are considered, patient self-testing is the most cost-effective alternative, resulting in an overall cost saving.

Prediction of birth weight by ultrasound in the third trimester

OBJECTIVE

To compare the accuracy of predicted birth weight by the gestation-adjusted projection method using ultrasonographic measurements obtained just before and at term.

METHODS

The study group comprised patients with singleton pregnancies who underwent sonograms between 34.0 and 36.9 weeks' gestation (period 1) and at 37 weeks and beyond (period 2). The mean error in birth weight prediction, absolute birth weight error, and signed and absolute percent errors were compared with paired t tests. Thus, each patient served as her own control.

RESULTS

The study included 138 patients undergoing 276 sonograms. The mean absolute error of the predicted birth weight was smaller for period 1 than for period 2 (197 +/- 167 g compared with 235 +/- 209 g, P =.019). The mean absolute percent error was 6.2 +/- 5.2% for period 1 compared with 7.4 +/- 6.3% for period 2 (P =.019). These same trends were observed when fetuses with suspected growth abnormalities were examined separately. Averaging data from both gestational periods did not improve the prediction of birth weight.

CONCLUSION

Sonograms between 34.0 and 36. 9 weeks' gestation allow for more accurate prediction of birth weight than sonograms later in gestation. Though these differences are small and not clinically significant, this study indicates that serial sonograms in the late third trimester do not improve the ability to predict birth weight, even in abnormally grown fetuses. A single sonogram between 34 and 37 weeks' gestation is recommended for prediction of birth weight.

Effect of vasovasostomy on contralateral testicular damage associated with unilateral vasectomy in mature and immature Lewis rats

OBJECTIVE

We sought to determine if laser-assisted vasovasostomy could reverse the contralateral histologic testicular changes associated with unilateral vasectomy.

DESIGN

A prospective, randomized, blinded, controlled study.

SETTING

Animal microsurgical laboratory, St. John's Mercy Medical Center, St. Louis, Missouri.

PATIENT(S)

Twenty mature and 20 immature male Lewis rats.

INTERVENTION(S)

Ten mature and 10 immature male Lewis rats underwent unilateral vasectomy. At 5 months, testicular biopsy and laser-assisted vasovasostomies were performed followed 2 months later by evaluation of vas patency and repeat testicular biopsy. Control animals consisted of 10 rats in each group, 5 that underwent sham operations and 5 that had halothane anesthesia alone.

RESULT(S)

In the immature and mature groups unilateral vasectomy resulted in marked contralateral testicular damage in 30% (3 of 10) and 50% (5 of 10), respectively. Vas patency determined 2 months after vasovasostomy was 80% (8 of 10) in the mature group and 89% (8 of 9) in the immature group. No animal that had contralateral testicular changes after vasectomy and a patent vas after vasovasostomy showed improvement in testicular histology.

CONCLUSION(S)

It appears that contralateral testicular damage associated with unilateral vasectomy is not improved 2 months after successful vasovasostomy in mature or immature Lewis rats.

In situ disappearance of malate from alfalfa and bermudagrass hay

The objectives of this study were to determine the rate of malate and dry matter disappearance from different forages in the rumen. Four nonlactating, ruminally cannulated Holstein cows were fed a hay-based diet. Samples of early and late harvested alfalfa, Coastal bermudagrass, and Tifton 85 bermudagrass hays were ground, placed in nylon in situ bags, and ruminally incubated for 0, 0.5, 1, 2, 4, 8, 12, 24, and 48 h. After incubation, samples were rinsed, freeze-dried, extracted, and analyzed for malate content by HPLC with an organic acid column. When forages were incubated in the rumen, malate concentrations were less than 0.55 mg/g of dry matter at 0.5 h and remained low for the 48-h incubation period. These results suggest that malate was solublized and utilized within 30 min after reaching the rumen. Dry matter digestibility of both forages increased with time and was different across forages. Both alfalfa samples were digested to a greater extent between 0.5 and 24 h than either type of bermudagrass, but after 48 h the early maturity Tifton 85 digestibility was similar to alfalfa. Even though it is more common to feed unground forages to ruminants, these in situ results suggest that once malate is available in the rumen it will disappear quickly.

The cost-effectiveness of different management strategies for patients on chronic warfarin therapy

OBJECTIVE

To examine the cost-effectiveness of moving from usual care to more organized management strategies for patients on chronic warfarin therapy.

DESIGN

Using information available in the scientific literature, supplemented with data from a large health system and, when necessary, expert opinion, we constructed a 5-year Markov model to evaluate the health and economic outcomes associated with each of three different anticoagulation management approaches: usual care, anticoagulation clinic testing with a capillary monitor, and patient self-testing with a capillary monitor.

PATIENTS

Three hypothetical cohorts of patients beginning long-term warfarin therapy were used to generate model results.

MAIN RESULTS

Model results indicated that moving from usual care to anticoagulation clinic testing would result in a total of 1.7 thromboembolic events and 2.0 hemorrhagic events avoided per 100 patients over 5 years. Another 4.0 thromboembolic events and 0.8 hemorrhagic events would be avoided by moving to patient self-testing. When direct medical care costs and those incurred by patients and their caregivers in receiving care were considered, patient self-testing was the most cost-effective alternative, resulting in an overall cost saving.

CONCLUSIONS

Results illustrate the potential health and economic benefits of organized care management approaches and capillary monitors in the management of patients receiving warfarin therapy.

Involvement of estrogens in the process of sex differentiation in two fish species: the rainbow trout (Oncorhynchus mykiss) and a tilapia (Oreochromis niloticus)

In order to study the physiological implication of sex steroid hormones in gonadal sex differentiation in fish, we first investigated the potential role of estrogens using two fish models: the rainbow trout (Oncorhynchus mykiss) and a tilapia species (Oreochromis niloticus). All experiments were carried out on genetically all-male (XY) and all-female (XX) populations. In vivo treatments with an aromatase inhibitor (ATD, 1,4,6- androstatriene-3-17-dione) result in 100% masculinization of an all-female population in rainbow trout (dosage 50 mg/kg of food) and 75.3% in tilapia (dosage 150 mg/kg of food). In tilapia, the effectiveness of the aromatase inhibition by ATD is demonstrated by the marked decrease of the gonadal aromatase activity in treated animals versus control. No masculinization is obtained following treatment with an estrogen receptor antagonist (tamoxifen) in both species. Aromatase and estrogen receptor gene expression was studied in rainbow trout by semi-quantitative RT-PCR in gonads sampled before, during and after sex-differentiation. Aromatase mRNA is specifically detected in female gonads, 3 weeks before the first sign of histological sex-differentiation, i.e., first female meiosis. Aromatase expression in male gonads is at least a few hundred times less than in female gonads. Estrogen receptor gene is expressed in both male and female gonads at all stages with no dimorphic expression between sexes. Specific aromatase gene expression before ovarian differentiation was also demonstrated using virtual Northern blot, with no expression detected in male differentiating gonads. From these results it can be concluded that estrogen synthesis is crucial for ovarian differentiation, and transcription of the aromatase gene can be proposed as a key step in that process in fish.

Fermentation of fenugreek fiber, psyllium husk, and wheat bran by Bacteroides ovatus V975

The objective of this study was to evaluate the ability of the human colonic bacterium Bacteroides ovatus V975 to ferment fenugreek fiber (Fenufibers), psyllium husk (Metamucil), and wheat bran (Wheat Chex). Strain V975 was incubated in basal medium that contained 0.1 g of each fiber source for 0, 24, or 48 h. Little digestion of either fiber source was detected over 48 h, and little acetate or succinate was produced. From the lack of significant fiber digestion and fermentation by B. ovatus, it seems that all three fiber sources could be used as dietary supplements to increase roughage in the human diet.

The pediatric critical care nurse practitioner: evolution and impact

This nonexperimental, descriptive pilot study evaluated the role and impact of two pediatric critical care nurse practitioners (PCCNPs) in the pediatric intensive care unit (PICU) at a tertiary care children's hospital. Questions posed included: 1) Are parents satisfied with the care their child and family received from the PCCNP in the PICU?; 2) Are staff nurses satisfied with the role of the PCCNP in the PICU?; and 3) Is there a difference between the care delivered by the PCCNP and the pediatric resident staff in nutritional management and discharge planning? Study methodology included a retrospective chart review of 25 PCCNP and 25 pediatric resident staff patient charts and a questionnaire survey of a convenience sample of parents and staff nurses over a 6-month study period. Overall, parents reported that the care their children received from the PCCNP was adequate. Staff nurses were satisfied with nurse practitioner (NP) care and supported the PCCNP role. There were no significant differences in the nutritional management of the children cared for by residents and PCCNPs. However, the PCCNPs initiated documentation of discharge planning with a greater frequency and earlier in the child's hospitalization, as compared to medical staff practice. Study findings support the use of the PCCNP in the PICU as care is comparable to that of the pediatric resident staff.