Wagyu-Angus cross improves meat tenderness compared to Angus cattle but unaffected by mild protein restriction during late gestation

For the spring-calving beef herds, late gestation coincides with winter and early spring, when cows are dependent on feed supplements with low quality hay, which is hard to meet their nutrient requirements. However, the effects of deficiencies of metabolizable protein intake during late gestation on offspring beef quality are unclear. Wagyu cattle have excellent marbling, and insemination with Wagyu vs Angus semen is a practical option for beef producers to improve beef quality. To test, Angus cows (621 ± 73 kg) were selected and randomly separated into two groups. Each group was inseminated with either Angus or Wagyu semen. During the last 90 days of gestation, cows in each group were further separated and received either a low protein diet (85% of the NRC metabolizable protein requirement), which was a low quality hay-based diet common in northwestern region of the U.S., or an adequate protein diet (108% NRC requirement). All progeny was managed together and harvested at a final BW of 576.5 ± 16.6 kg. Wagyu-sired offspring had higher marbling scores and quality grades than Angus (P < 0.01). Protein supplementation did not affect Slice Shear Force (SSF) in either breeds (P = 0.60). However, Wagyu-sired cattle had lower SSF than Angus-sired (P < 0.01). In addition, Wagyu-sired cattle had higher intramuscular fat (P < 0.05) and total collagen content (P < 0.05), but Angus-sired had greater mature collagen cross-links, as shown by higher contents of Pyridinoline (P < 0.01) and Ehrlich Chromogen (P < 0.01). Consistently, the mRNA expression of enzymes catalyzing collagen cross-linking was higher in Angus-sired offspring, including Plod 1 (P < 0.05), Plod 2 (P = 0.08), and P4Hα 2 (P < 0.01). In conclusion, Wagyu-sired cattle had greater tenderness and marbling score compared to Angus-sired, which was associated with lower collagen cross-links. Feeding mature grass hay-based diet with relatively low protein content during late gestation had no major effect on beef quality of subsequent cattle.

Fatty acid composition of adipose tissue and muscle from Jersey steers was affected by finishing diet and tissue location

To determine the impacts of finishing diet and tissue type and location on fatty acid composition and palatability of Jersey beef, twenty steers were assigned to a factorial treatment design with initial weight (Light vs. Heavy) and finishing diet (70 vs. 85% concentrate) as treatments. Ribeye steaks were collected for sensory evaluation. Muscle, seam and subcutaneous (s.c.) fat from steaks, kidney fat (KF) and omental fat (OMF) were collected for fatty acid analysis. Initial weight and finishing diet had little impact on beef palatability. The 85% concentrate decreased polyunsaturated fatty acids (PUFA) in muscle and increased trans fatty acids in all tissues (P<0.05). The monounsaturated:saturated fatty acid ratio (MUFA:SFA) was highest in s.c. fat, intermediate in muscle and seam fat, and lowest in KF and OMF. The PUFA:SFA was highest in muscle, intermediate in s.c. and seam fat, and lowest in KF and OMF. Fatty acid composition differed greatly among tissues and the lower concentrate diet increased omega-3 and PUFA percentages in muscle.

Effect of sampling fat location and cooking on fatty acid composition of beef steaks

To investigate the impact of sampling fat location and cooking on fatty acid composition of beef steaks, 21 raw steaks from crossbred steers were dissected to obtain outer (OSC) and inner subcutaneous fat (ISC), seam fat, marbling, and lean muscle. Twenty-one cooked steaks were dissected to obtain OSC, ISC, seam fat, surface and inner muscle. Trans-vaccenic acid and c9, t11-CLA percentages were lower (P<0.05) in lean muscle than subcutaneous (s.c.) fat or marbling. Monounsaturated: saturated fatty acid ratios were lower (P<0.05) in seam fat and marbling than s.c. fat or lean muscle. Linoleic and linolenic acid levels were highest in lean muscle and longer chain n-6 and n-3 fatty acids were only detected in lean muscle. Cooking did not change fatty acid composition dramatically except that n-6: n-3 ratio in s.c. and seam fat decreased after cooking (P<0.05).

A direct method for fatty acid methyl ester synthesis: application to wet meat tissues, oils, and feedstuffs

A simplified protocol to obtain fatty acid methyl esters (FAME) directly from fresh tissue, oils, or feedstuffs, without prior organic solvent extraction, is presented. With this protocol, FAME synthesis is conducted in the presence of up to 33% water. Wet tissues, or other samples, are permeabilized and hydrolyzed for 1.5 h at 55 degrees C in 1 N KOH in MeOH containing C13:0 as the internal standard. The KOH is neutralized, and the FFA are methylated by H(2)SO(4) catalysis for 1.5 h at 55 degrees C. Hexane is then added to the reaction tube, which is vortex-mixed and centrifuged. The hexane is pipetted into a gas chromatography vial for subsequent gas chromatography. All reactions are conducted in a single screw-cap Pyrex tube for convenience. The method meets many criteria for fatty acid analysis, including not isomerizing CLA or introducing fatty acid artifacts. It is applicable to fresh, frozen, or lyophilized tissue samples, in addition to oils, waxes, and feedstuffs. The method saves time and effort and is economical when compared with other methods. Its unique performance, including easy sample preparation, is achieved because water is included rather than eliminated in the FAME reaction mixtures.

A direct method for fatty acid methyl ester synthesis: application to wet meat tissues, oils, and feedstuffs

A simplified protocol to obtain fatty acid methyl esters (FAME) directly from fresh tissue, oils, or feedstuffs, without prior organic solvent extraction, is presented. With this protocol, FAME synthesis is conducted in the presence of up to 33% water. Wet tissues, or other samples, are permeabilized and hydrolyzed for 1.5 h at 55 degrees C in 1 N KOH in MeOH containing C13:0 as the internal standard. The KOH is neutralized, and the FFA are methylated by H(2)SO(4) catalysis for 1.5 h at 55 degrees C. Hexane is then added to the reaction tube, which is vortex-mixed and centrifuged. The hexane is pipetted into a gas chromatography vial for subsequent gas chromatography. All reactions are conducted in a single screw-cap Pyrex tube for convenience. The method meets many criteria for fatty acid analysis, including not isomerizing CLA or introducing fatty acid artifacts. It is applicable to fresh, frozen, or lyophilized tissue samples, in addition to oils, waxes, and feedstuffs. The method saves time and effort and is economical when compared with other methods. Its unique performance, including easy sample preparation, is achieved because water is included rather than eliminated in the FAME reaction mixtures.

Effects of supplemental fat on growth performance and quality of beef from steers fed barley-potato product finishing diets: I. Feedlot performance, carcass traits, appearance, water binding, retail storage, and palatability attributes

To measure the effects of dietary fat on feedlot performance, carcass characteristics, and beef appearance, moisture binding, shelf life, and palatability, 168 crossbred beef steers (317 +/- 1.0 kg) were allotted randomly, within weight blocks, to a randomized complete block design with a 3 x2 + 1 factorial arrangement of dietary treatments. Main effects were level of yellow restaurant grease (RG; 0, 3, or 6%) and level of alfalfa hay (AH; 3.5 or 7%), with the added treatment of 6% tallow and 7% AH in barley-based diets containing 15% potato by-product and 7% supplement fed for 165 d (all dietary levels on a DM basis). Dietary treatment did not (P >0.10) affect DMI, LM area, beef brightness, or beef texture. Level of RG linearly increased (P <0.05) ADG from 1.48 to 1.60 kg/d, diet NE(m) from 2.4 to 2.6 Mcal/kg, diet NE(g) from 1.7 to 1.9 Mcal/kg, and internal fat from 2.1 to 2.4%. Level of RG linearly increased (P <0.05) G:F from 0.184 to 0.202, but decreased (P <0.05) beef firmness score from 3.0 to 2.8 and fat luster score from 3.1 to 2.8. Level of AH did not (P >0.10) affect any of the measurements; however, AH interacted with level of RG on fat thickness and yield grade (linear; P <0.05), as well as marbling score and percentage of carcasses grading USDA Choice (quadratic; P <0.05). Fat thickness and yield grade increased with increasing RG level in 3.5%, but not in 7%, AH diets. In steers fed 3.5% RG, marbling scores and percentage of carcasses grading Choice were greatest when fed with 3.5% AH, and least when fed 7% AH. Steers fed tallow had lower marbling scores (P = 0.01) and percentage of carcasses grading Choice (P = 0.066) than those fed RG. Retail storage attributes, including visual and instrumental color, decreased during storage (P <0.01), but were not (P >0.10) affected by diet. Trained sensory panel scores for initial tenderness increased quadratically (P = 0.07) as dietary RG increased, but diet did not (P >0.10) affect drip loss, cooking loss, or trained sensory panel scores for sustained tenderness, initial and sustained juiciness, and beef flavor. Therefore, RG increased diet energy, improved performance, and increased carcass fatness; however, dietary fat and AH did not affect most measurements of water retention, color stability, or palatability of beef.

Education in end-of-life care: bridging disciplinary and institutional boundaries

This paper describes the development of an interdisciplinary, interinstitutional seminar in palliative care for South Dakota students in medicine, nursing, pharmacy, chaplaincy, and social work. Student outcomes from six seminars conducted during 2001-2004 are reported, and recommendations for future educational efforts are outlined.

Effects of supplemental fat on growth performance and quality of beef from steers fed barley-potato product finishing diets: II. Fatty acid composition of muscle and subcutaneous fat1

One hundred sixty-eight crossbred steers (317.1 +/- 1.0 kg) were used to evaluate the effects of supplemental fat in finishing diets on the fatty acid composition, including the 9,11 isomer of conjugated linoleic acid, of beef. Steers were allotted within three weight blocks to a randomized complete block design with a 3 x 2 + 1 factorial arrangement of dietary treatments. Main effects were level of yellow restaurant grease (RG; 0, 3, and 6%), and level of alfalfa hay (AH; 3.5 and 7%) with an added treatment containing 6% tallow (T) and 7% AH in barley-based diets containing 15% potato by-product and 7% supplement (all dietary levels are on a DM basis) fed for an average of 165 d. Fatty acids of the LM and s.c. fat from four randomly selected steers per pen were quantified using GC after methylation with sodium methoxide. Dietary treatment did not (P > 0.10) affect total fatty acid (FA) content of the LM (143 +/- 5.2 mg/g) or fat (958 +/- 7.9 mg/g). Myristic acid increased linearly (P < 0.01) with increasing RG from 3.1 to 3.7 +/- 0.1 g/100 g of FA in muscle. Stearic acid increased linearly (P < 0.05) as RG increased in the diet, from 11.4 to 12.9 +/- 0.4 g/100 g of FA in LM and from 9.9 to 12.2 +/- 0.3 g/100 g of FA in fat. Compared with T, steers fed 6% RG had more (P < 0.05) oleic acid in LM (42.7 vs. 40.3 +/- 0.5 g/100g FA) and in fat (43.0 vs. 40.9 +/- 0.5 g/100g FA). The cis-9, trans-11 conjugated linoleic acid (CLA) increased quadratically (P < 0.01) with increasing dietary RG in LM from 0.45 to 0.64 to 0.62 +/- 0.03 g/100 g of FA and increased in fat from 0.61 to 0.84 to 0.83 +/- 0.04 g/100 g of FA. Moreover, cis-9, trans-11 CLA was higher (P < 0.05) in fat from steers fed RG compared with T (0.81 vs. 0.69 +/- 0.04 g/100 g of FA), and tended to be higher (P = 0.07) in muscle (0.62 vs. 0.54 +/- 0.03 g/100 g of FA. Feeding yellow restaurant grease increased content of cis-9, trans-11 CLA in beef without an increase total FA content.

Effects of medroxyprogesterone acetate (MAP) on ovarian antral follicle development, gonadotrophin secretion and response to ovulation induction with gonadotrophin-releasing hormone (GnRH) in seasonally anoestrous ewes

When ovulation is induced with gonadotrophin-releasing hormone (GnRH) in anoestrous ewes, a proportion of animals fail to form normal (full-lifespan) corpora lutea (CL). Progesterone treatment before GnRH prevents luteal inadequacy. It remains uncertain whether a similar effect, achieved with medroxyprogesterone acetate (MAP) from intravaginal sponges, is mediated by influences on growing ovarian follicles and/or secretion of gonadotrophic hormones, before and after GnRH treatment. Two experiments were performed, on 13 and 11 anoestrous Western white-faced ewes, respectively. Seven and six ewes, respectively, received MAP-containing sponges (60 mg) for 14 days; the remaining ewes served as untreated controls. To test the effect of timing of GnRH administration after pre-treatment with MAP-releasing sponges, GnRH injections (250 ng every 2h for 24h followed by a bolus injection of 125 microg of GnRH i.v.) were given either immediately (Experiment 1) or 24h after sponge removal in the treated ewes (Experiment 2). Ovarian follicular dynamics (follicles reaching >or=5mm in size) and development of luteal structures were monitored using transrectal ultrasonography. In Experiment 1, the mean ovulation rate (0.7+/-0.3 and 1.0+/-0.4) and proportion of ovulating ewes (57 and 67%, respectively) did not vary (P>0.05) between MAP-treated and control ewes. Normal (full-lifespan) CL were detected in 29% of treated and 67% of control ewes (P>0.05). In Experiment 2, the mean ovulation rate (2.3+/-0.2 and 1.2+/-0.6; P<0.05) and percentage of ewes with normal (full-lifespan) CL (100 and 40%, respectively; P<0.10) were greater in the treated compared to control ewes. In Experiment 1, the mean peak concentration of the GnRH-induced LH surge was lower (P<0.05) in MAP-treated than in control ewes. There were no significant differences between MAP-treated and control ewes in the characteristics of follicular waves, mean daily serum FSH concentrations, and secretory parameters of LH/FSH, based on intensive blood sampling conducted 1 day before sponging and 1 day before sponge removal. It is concluded that treatment with MAP has no effect on the tonic secretion of LH/FSH or follicular wave development in anoestrous ewes. However, the GnRH-stimulated LH discharge was attenuated in the ewes that received MAP-impregnated sponges for 14 days and were treated with GnRH immediately after sponge withdrawal. Ovulatory response and CL formation were increased when GnRH was administered 24 h after sponge removal.

Ovarian responses in gonadotrophin-releasing hormone-treated anoestrous ewes: follicular and endocrine correlates with luteal outcome

The relationships between the development of antral follicles (growing from 3 to > or = 5 mm diameter), hormone secretion (luteinizing hormone (LH), follicle-stimlating hormone (FSH), oestradiol and progesterone), ovulation and the formation of luteal structures in response to gonadotrophin-releasing hormone (GnRH) were examined in 24 anoestrous Western White Face ewes (May-July). Ewes were monitored by transrectal ovarian ultrasonography for 34 days, commencing 15 days before the administration of GnRH. Following treatment with GnRH, 83% (20/24) of ewes ovulated. Twenty-five per cent of all ewes (6/24) subsequently had normal (full-life span) corpora lutea (CL), 37% (9/24) had inadequate CL, 17% (4/24) had both normal and inadequate CL, 17% (including three of four anovular ewes and one ewe with inadequate CL) formed luteinized follicles and only 4% (1/24) did not ovulate or produce any luteal structure. None of the variables of follicular growth (follicles reaching > or = 5 mm diameter) differed between follicles that either ovulated or failed to ovulate and there was no evident correlation between the age or stage of development of ovulatory sized antral follicles and the type of luteal structure formed, except for luteinized unovulated follicles; these follicles all emerged within 3 days of GnRH injection. Mean serum concentrations of FSH and oestradiol before treatment did not differ (P>0.05) between ewes with different ovarian responses, but peaks of fluctuations in serum concentrations of FSH in daily samples were higher in ewes that produced normal CL compared with ewes with inadequate CL. After GnRH treatment, oestradiol secretion was higher in ewes that formed luteinized unovulated follicles than in all ewes with inadequate CL (P<0.05). The peak concentration of the GnRH-induced LH surge was higher and the interval from GnRH to peak LH discharge was shorter in ewes with inadequate CL compared with ewes that had normal CL after ovulation (P<0.05). In conclusion, ovulatory sized antral follicles at a similar stage of their life span can give rise to either normal or inadequate CL and a proportion of these follicles do not ovulate in response to GnRH in seasonally anoestrous ewes. This suggests differences in ovarian follicular responsiveness to gonadotrophic stimuli. Both the amplitude of episodic elevations in daily serum FSH concentrations and the characteristics of the pre-ovulatory LH surge may be important for luteogenesis following ovulation.

Student Outcomes of the Healing Web: Evaluation of a Transformative Model for Nursing Education

The Healing Web is a transformative nursing model, bridging gaps between nursing education and practice, baccalaureate and associate degree education, and public and private educational institutions. It is an educational prototype in which nursing students experience collaborative clinical practice in a differentiated practice model. Based on the Healing Web framework, it was hypothesized that the educational partnership model would influence specific student competencies (i.e., caring abilities, leadership skills, assertiveness, and professional nursing behaviors). Students in the Healing Web program scored higher in caring knowing, caring courage, leadership, and assertiveness than their counterparts who participated in traditional clinical experiences. Students identified collaboration, partnership with students and staff, and learning to value different nursing roles as primary benefits of the experience. Findings support the contribution of Healing Web experiences to selected student outcomes, but the research is limited by instrumentation, small numbers, and the question of adequate "dosage." Future research will emphasize qualitative methods to explicate significant concepts more completely.

A model for scholarship in nursing: the case of a private liberal arts college

Faculty in the Department of Nursing at Augustana College, Sioux Falls, SD, focused their faculty development efforts for the 1997-1998 academic year on the creation of a scholarship model that would be both discipline-specific and relevant to Augustana's private liberal arts college identity. Rooted in Boyer's seminal re-examination of scholarship in academia, the Augustana model defines scholarship in nursing and delineates dimensions of scholarship, as well as the qualities of a scholar and criteria for evaluating scholarly endeavors. This evolving model has proven useful as a framework for faculty self-evaluation and peer review, as a guide for orienting undergraduate and graduate students to their own scholarly development, and as a framework to define criteria for final graduate student projects. The model is presented as an invitation to individual and collective scholarship development for every clinician, educator, theorist, and researcher in nursing.

Effects of tallow on the energy metabolism of wethers fed barley finishing diets

A balance trial was conducted to titrate the effects of tallow on the energy metabolism of wethers fed barley finishing diets. Six dietary levels of tallow (0, 2, 4, 6, 8, or 10%) in a barley finishing diet were fed to six crossbred wethers (35+/-1.1 kg) in a randomized complete block design. Diets were 73% barley, 10% tallow and(or) bentonite, 10% alfalfa pellets, and 7% supplement. There was no effect of tallow level on OM intake (1,103.1+/-51 g/d), OM digestibility (84+/-0.9%), GE digestibility (83+/-1.1%), or cell solubles digestibility (84.2+/-1.2%). The level of tallow quadratically decreased ADF digestibility (P < 0.05), methane emissions, and methane energy as a percentage of GE P < 0.01). There were linear increases in dietary GE (megacalories per kilogram of OM [P < 0.01]), dietary DE (megacalories per kilogram of OM [P < 0.05]), and dietary ME (megacalories per kilogram of OM [P < 0.01]), as dietary tallow increased. Numbers of ruminal protozoa (Entodinium spp. and Polyplastron sp.) decreased linearly (P < 0.05) with increased level of tallow. The energy value of tallow (calculated by difference) was low. The total-tract fatty acid digestibility of tallow was calculated by linear regression, without intercept, after accounting for the fatty acids digested from the base diet (0% tallow fed to a wether in a period). Fatty acids of the same carbon length were pooled for the regression analysis. All linear regressions were significant (P < 0.10) indicating no effect of tallow level on fatty acid digestibility. Lauric acid had low digestibility. The high digestibility of all C16 (89%) and C18 (104%) fatty acids suggests an effect of tallow on endogenous and microbial fatty acid excretion. Fatty acid digestibility was probably a minor contributor to the low energy content of tallow, calculated by difference, in these diets.

Refractive changes caused by hypoxia after laser in situ keratomileusis surgery

OBJECTIVE

To determine whether hypoxia induces refractive changes in subjects who have had laser in situ keratomileusis (LASIK) refractive surgery.

DESIGN

Prospective paired eye clinical trial.

PARTICIPANTS

There were 20 LASIK subjects (40 eyes) and 20 myopic non-LASIK controls (40 eyes).

INTERVENTION

Each subject had one eye exposed to ocular surface hypoxia (humidified nitrogen) by use of an airtight goggle system at sea level for 2 hours. The other eye was simultaneously exposed to humidified, compressed air (21% oxygen) with the same airtight goggle system.

MAIN OUTCOME MEASURES

Keratometry, cycloplegic refraction, and pachymetry were compared before and after exposure by use of repeated measures analysis of variance.

RESULTS

A significant myopic shift (P: < 0.01) occurred in LASIK corneas exposed to hypoxia compared with myopic control subjects. A significant increase in corneal thickening occurred symmetrically in both LASIK and control subjects exposed to hypoxia. There was a trend toward corneal steepening (keratometry) in LASIK subjects, but this was not statistically significant.

CONCLUSIONS

These results suggest that ocular surface hypoxia induces a myopic shift in LASIK subjects.

Unusual aortic arch variation: distal origin of common carotid arteries

As part of a larger study, the aortic arch and its branches were removed en bloc at autopsy from men of Japanese ancestry born in Hawaii. Of the 193 arterial trees examined, 182 (94.3%) had a typical branching pattern (e.g., brachiocephalic trunk, left common carotid, and left subclavian arteries, in that order). Two specimens had only two branches arising from the aortic arch, a common trunk uniting the brachiocephalic and left common carotid arteries and a left subclavian artery. Nine individuals (4.6%) had four branches off the aortic arch; in eight of these cases (4.1%), the left vertebral artery originated directly off the aortic arch just proximal to, or as a common trunk with, the left subclavian artery. A unique aortic arch branching pattern was found in one of these men. The four arteries arising from the arch of the aorta were, in sequence: right subclavian, left subclavian, right common carotid, and left common carotid. The literature on aortic arch variations is reviewed and the possible embryonic development of these branching patterns and their clinical significance is discussed briefly.

Disposable plastic liners for a colostomy appliance: a controlled trial and follow-up survey of convenience, satisfaction, and costs

PURPOSE

The effectiveness of a disposable liner designed for a 2-piece colostomy appliance pouch was evaluated.

DESIGN

Randomized, crossover trial with follow-up surveys.

SETTING AND SUBJECTS

Nineteen participants were recruited from the Mayo Clinic in Scottsdale, Arizona, and the surrounding community.

INSTRUMENTS

A Daily Colostomy Care Evaluation Record and tally sheet of times for ostomy care were designed by the authors.

METHODS

Participants, acting as their own controls, were randomly assigned to use either an unlined or a lined appliance for 9 days. On day 10, participants switched to the opposite regimen, which was maintained through day 18. They recorded the time required for daily colostomy care and perceptions of the lined and unlined appliances. The volume of ostomy supplies and cost were recorded at baseline, 1, 3, and 5 to 9 months after the initial trial.

RESULTS

Odor, bother, perceived severity of leakage, and partner acceptance were better with unlined than lined appliances. Half of the participants were using a liner > or =75% of the time 3 months after the trial. There was no difference in cost when lined versus unlined ostomy systems were compared. Participants who chose to use the liners indicated high satisfaction. Problems noted included an inadequate seal with the liner (58%), inadequate liner size (16%), retention of flatus by the liner (11%), and difficulty removing the full liner (11%).

CONCLUSIONS

The study supports recommending liners to patients who have a modest amount of fecal output or flatus. However, patients who are unable to manipulate the seal or have a large output volume are unlikely to find the liners a convenience. Satisfaction with the liners was sufficient to warrant investigation and design of a lined device with an improved design, greater capacity, and tighter seal.

Effects of graded levels of potato by-products in barley- and corn-based beef feedlot diets: I. Feedlot performance, carcass traits, meat composition, and appearance

To measure effects of diet on feedlot performance, carcass characteristics, and beef appearance, 144 crossbred beef steers (333+/-.44 kg) were allotted within weight block (3) to a randomized complete block design with a 2 x 3 factorial arrangement of dietary treatments. Main effects were grain (barley or corn) and level of potato by-product (PB) (0, 10, or 20% of diet DM). Steers were fed diets containing 83% concentrate (grain plus PB), 10% supplement, and 7% alfalfa on a DM basis for an average of 130 d. Level of PB quadratically affected (P < .10) DM intake and gain such that steers fed 10% PB ate more and gained faster. Corn-fed steers were more (P < .05) efficient (5.8 vs 6.3 kg DM/kg gain) and had more (P < .05) kidney, pelvic, and heart fat (2.2 vs 2.0%) than barley-fed steers. A grain x PB interaction was detected (P < .10) for marbling score, which was minimized in steers fed barley diets (small 0) but maximized in those fed corn diets (small 30) at 10% PB. Diet did not affect beef firmness or beef color score. Barley-fed beef had whiter fat (P < .05) than corn-fed beef (2.6 vs 2.9 on a 1 to 7 scale); however, fat luster score was not affected by diet. Small differences were noted in fatty acid profile, purge, drip loss, and muscle pH. No differences were noted in color measurements due to dietary treatment over 7 d of retail shelf life. Overall, differences were small and probably not biologically important. These results indicate that these diets had minimal effects on beef appearance and carcass characteristics, meat composition, and water retention properties.

Effects of graded levels of potato by-products in barley- and corn-based beef feedlot diets: II. Palatability

The objective of this study was to evaluate the effects of barley- or corn-based diets containing 0, 10, or 20% potato by-product (DM basis) on Warner-Bratzler shear force and palatability of beef. One hundred forty-four crossbred beef steers (333+/-.44 kg) were allotted within weight block (3) to a randomized complete block design with a 2 x 3 factorial arrangement of dietary treatments. Main effects were grain (barley or corn) and level of potato by-product (0, 10, or 20% of diet DM). There were a total of 18 pens with eight steers per pen and three pens per treatment. Steers were fed diets containing 83% concentrate (grain plus potato by-product), 10% supplement, and 7% alfalfa (DM basis) for an average of 130 d. Longissimus muscle cuts were used for Warner-Bratzler shear force determination (four steers per pen) and evaluation (two steers per pen) by a 10-member trained laboratory panel, a professional flavor/texture profile panel, and by consumer panels. Diet did not affect (P > .10) Warner-Bratzler shear force or trained laboratory panel tenderness, juiciness, and flavor intensity scores. Flavor/texture profile panel scores indicated feeding a corn-based diet as opposed to barley-based diet produced a more appropriate well-balanced and well-blended beef flavor and texture. However, the magnitudes of the differences were relatively small, and flavor and texture amplitude ratings for both barley- and corn-fed beef were well above average. Beef from steers fed 10 or 20% potato by-product had lower (P < .05) incidences of inappropriate aromatics and aftertastes, which may have a slightly beneficial effect on beef flavor, but flavor amplitude was not affected (P > .05) by level of potato. Moreover, consumer panel overall acceptability scores were not affected by diet. Thus, feedlot diets containing corn or barley with or without potato by-product should result in palatable beef products.

Interaction between the serotonin transporter gene and neuroticism in cigarette smoking behavior

Cigarette smoking behavior is influenced by both personality traits and inherited factors. Previous research showed that neuroticism-a broad personality domain that includes anxiety, depression, impulsiveness and vulnerability-increases the risk of being a smoker, primarily because of difficulty in quitting. Neuroticism has also been associated with the 5-HTTLPR, a functional polymorphism in the promoter for the serotonin transporter gene. We used population and family-based methods to analyze the joint effects of the 5-HTTLPR and neuroticism on smoking behavior in a population of 759 never, current, and former smokers, all members of sib-pairs. Our main finding is that smoking behavior is influenced by an interaction between neuroticism and 5-HTTLPR genotype. Specifically, neuroticism was positively correlated with current smoking and negatively associated with smoking cessation in individuals and siblings with poorly transcribed 5-HTTLPR-S genotypes, but not in those with the more highly expressed 5-HTTLPR-L genotype. Individuals with both a 5-HTTLPR-S genotype and a high level of neuroticism had the greatest difficulty in quitting smoking. These data, if replicated, suggest that smoking behavior is more strongly influenced by the combination of the serotonin transporter gene and neuroticism than by either factor alone, and that personality scores and 5-HTTLPR genotype may predict the clinical efficacy of certain smoking cessation drugs.

Reversal of tetracycline resistance mediated by different bacterial tetracycline resistance determinants by an inhibitor of the Tet(B) antiport protein

Active efflux is a useful strategy by which bacteria evade growth inhibition by antibiotics. Certain semisynthetic tetracycline (TC) analogs, substituted at the 13th carbon at C-6 on ring C of the TC molecule, blocked TC efflux as revealed in everted membrane vesicles from class B TC-resistant (Tcr) Escherichia coli (M. L. Nelson, B. H. Park, J. S. Andrews, V. A. Georgian, R. C. Thomas, and S. B. Levy, J. Med. Chem. 36:370-377, 1993). A representative C-13-substituted analog, 13-cyclopentylthio-5-OH-TC (13-CPTC), was shown to competitively inhibit TC translocation by the Tet(B) protein, blocking the uptake of TC into vesicles and therefore the efflux of TC from whole cells. Against Tcr E. coli, 13-CPTC, when used in combination with doxycycline, produced synergistic inhibition of growth. 13-CPTC was shown to increase the uptake of [3H]TC into the resistant cells. 13-CPTC alone was a potent growth inhibitor against TC-susceptible (Tcs) and Tcr Staphylococcus aureus and enterococci specifying class K or class L efflux-dependent TC resistance mechanisms or, unexpectedly, the class M ribosomal protection mechanism. These findings indicate that derivatives of TC, identified by their ability to block the Tet(B) efflux protein, can restore TC activity against Tcr bacteria bearing either of the two known resistance mechanisms. Blocking drug efflux and increasing intracellular drug concentrations constitute an effective approach to reversing TC resistance and may be generally applicable to other antibiotics rendered ineffective by efflux proteins.

A genetic association for cigarette smoking behavior

Dopaminergic genes are likely candidates for heritable influences on cigarette smoking. In an accompanying article, Lerman et al. (1999) report associations between allele 9 of a dopamine transporter gene polymorphism (SLC6A3-9) and lack of smoking, late initiation of smoking, and length of quitting attempts. The present investigation extended their study by examining both smoking behavior and personality traits in a diverse population of nonsmokers, current smokers, and former smokers (N = 1,107). A significant association between SLC6A3-9 and smoking status was confirmed and was due to an effect on cessation rather than initiation. The SLC6A3-9 polymorphism was also associated with low scores for novelty seeking, which was the most significant personality correlate of smoking cessation. It is hypothesized that individuals carrying the SLC6A3-9 polymorphism have altered dopamine transmission, which reduces their need for novelty and reward by external stimuli, including cigarettes.

A genetic association for cigarette smoking behavior

Dopaminergic genes are likely candidates for heritable influences on cigarette smoking. In an accompanying article, Lerman et al. (1999) report associations between allele 9 of a dopamine transporter gene polymorphism (SLC6A3-9) and lack of smoking, late initiation of smoking, and length of quitting attempts. The present investigation extended their study by examining both smoking behavior and personality traits in a diverse population of nonsmokers, current smokers, and former smokers (N = 1,107). A significant association between SLC6A3-9 and smoking status was confirmed and was due to an effect on cessation rather than initiation. The SLC6A3-9 polymorphism was also associated with low scores for novelty seeking, which was the most significant personality correlate of smoking cessation. It is hypothesized that individuals carrying the SLC6A3-9 polymorphism have altered dopamine transmission, which reduces their need for novelty and reward by external stimuli, including cigarettes.

Chemical and biological dynamics of tetracyclines

Key words: Tetracyclines, mechanism of action, biological activity.

Effects of barley cultivar on energy and nitrogen metabolism of lambs

The aim of this research was to compare energy values, nitrogen metabolism and diet digestibility of four barley (Hordeum vulgare L.) cultivars grown in two different years, to identify the most important factors affecting variation. Six wether lambs (39.4 ± 1.6 kg) were assigned within period in a randomized complete block design to barley cultivar (1990 Camelot, 1990 Cougbar, 1990 Steptoe, 1991 Boyer, 1991 Camelot and 1991 Steptoe) and consumed a diet of 83% barley, 10% alfalfa pellets and 7% supplement on a DM basis. During each 14-d period, feed, orts, fecal and urine samples were collected during the last 7 d and methane emissions were quantified. Digestibility of NDF polymeric monosaccharides was lower (P < 0.10) for weathers fed 1990 Steptoe than all cultivars other than 1991 Boyer and was positively correlated to methane production (r = 0.52). Barley DE was not different among cultivars but, because methane production was greater (P < 0.10) for lambs fed 1991 Boyer (38 L d−1) than for those fed 1990 Steptoe (21 L d−1) and 1990 Camelot (26 L d−1), barley ME content of 1991 Boyer (12.3 MJ kg−1 OM) was lower (P < 0.10) than for 1990 Steptoe (13.4 MJ kg−1 OM). Nitrogen digestibility in lambs fed Camelot grown both years was greater (P < 0.05) than for most cultivars. Absorbed nitrogen was greatest (P < 0.10) in lambs fed 1991 Camelot and nitrogen retention (g d−1) tended to be greater than 1990 Cougbar (P = 0.14) and 1990 Camelot (P = 0.16) fed lambs. Cougbar, Boyer and 1991 Steptoe had lower feeding quality for ruminants because of lower energy and/or nitrogen metabolism, while both years of Camelot and 1990 Steptoe had greater ME values. Methane production, digestibility of NDF polymeric monosaccharides and nitrogen metabolism were major factors contributing to variability among barley cultivars within and between years. Key words: Barley, lambs, methane, metabolizable energy

Variation in chemical composition and nutritional quality among barley cultivars for ruminants. 2. Digestion, ruminal characteristics and in situ disappearance kinetics

Two trials were conducted to compare the effects of feeding six different barley (Hordeum vulgare L.) cultivars on diet digestibility, DE content, and ruminal fermentation characteristics. In Trial 1, four steers (455 ± 1.6 kg) were used in a partially balanced incomplete block design and consumed a diet of 83% barley (Andre, Camelot, Clark, Cougbar, Harrington or Steptoe), 10% bromegrass hay and 7% supplement. Organic matter intake was lower (P < 0.10) for steers fed Clark, and in situ rate of disappearance of Steptoe was slower (P < 0.10) than other barleys. Acetate to propionate ratio was lower (P < 0.10) in ruminal fluid of steers fed Camelot than in that of those fed Andre, NDF digestibility was lower (54.7 vs. 69.2%), and digestion of NDF polymeric monosaccarides was lower (P < 0.10) for Camelot than for Andre. Scanning electron micrographs supported differences observed in chemical composition and in situ disappearance kinetics. In Trial 2, six steers (512 ± 1.8 kg) were used in a 6 × 6 Latin square design and consumed a diet of 83% barley (Boyer, Camelot, Clark, Harrington, Hesk or Steptoe), 10% bromegrass hay and 7% supplement. Steers fed Camelot had greater (P < 0.10) total tract NDF digestibility than steers fed Hesk and Steptoe. Total polymeric monosaccharide digestion was lower (P < 0.10) for Boyer (62.9%) than for any of the other cultivars (73.5%, average) except Hesk. In these two trials, NDF and NDF polymeric monosaccharide digestibilities were the major factors contributing to variability among barley cultivars in nutritional quality for ruminants. Key words: Barley, steers, digestibility, energy

Variation in chemical composition and nutritional quality among barley cultivars for ruminants. 1. Steer finishing performance, diet digestibilities and carcass characteristics

Inherent variability in chemical composition and nutritional value exists among barley (Hordeum vulgare L.) cultivars due to year grown, head morphology, growth habit and intended end use. Two trials were conducted to identify causal factors for variability among barley cultivars in animal performance, carcass characteristics, diet digestibility and digestible energy (DE) content. In feedlot trials, 144 large-frame beef steers (380 ± 1.6 kg in Trial 1, 372 ± 0.8 kg in Trial 2) were assigned within three weight blocks, eight to a pen, in a randomized complete block design and pens to treatments. Steers were fed a diet of 83% steam-rolled barley (Andre, Camelot, Clark, Cougbar, Harrington or Steptoe for 123 d in Trial 1; Boyer, Camelot, Clark, Harrington, Hesk or Steptoe for 119 d in Trial 2), 10% silage (wheat in Trial 1, oat in Trial 2), and 7% supplement on a dry matter (DM) basis. In Trial 1, Cougbar neutral detergent fiber (NDF) digestibility was significantly lower than Clark. Digestibility of other nutrients tended to be lowest for steers fed Cougbar and as a result, diet DE was lower (P < 0.05) for Cougbar than for Clark and Camelot. Diet DE and NDF digestibility were correlated (r = 0.69; P < 0.0001). Lower nutrient utilization by steers fed Cougbar resulted in lower performance. In Trial 2, steers fed Hesk had a poorer (P < 0.05) ratio of feed to gain than steers fed Camelot and Harrington and lower (P < 0.05) digestibility than steers fed Steptoe. In summary, data from these trials suggest that Cougbar and Steptoe are of lower nutritional value than other cultivars under the conditions of these studies. In these studies, digestibility of NDF was a major factor contributing to differences among cultivars. Key words: Barley, steers, digestibility, energy

Infectious crystalline keratopathy caused by Candida guilliermondii

PURPOSE

To describe the manifestations of infectious crystalline keratopathy caused by Candida guilliermondii in a corneal transplant performed for pseudophakic bullous keratopathy.

METHOD

Case report.

RESULTS

Candida guilliermondii was identified as the causative organism of an indolent infectious crystalline keratopathy. Incisional lamellar biopsy provided diagnostic culture and histopathologic results. Histopathology showed aggregates of yeast elements between corneal stromal lamellae, without inflammation. The infection progressed despite a 6-week course of topical amphotericin B and an additional 6-week course of topical and oral fluconazole. Repeat penetrating keratoplasty resulted in clear graft, with no recurrent infection.

CONCLUSIONS

Fungal keratopathy should be included in the differential diagnosis of infectious crystalline keratopathy. Numerous Candida species have been isolated in addition to the most common causative bacterial organism, Streptococcus viridans. Candida guilliermondii is yet one more causative agent of infectious crystalline keratopathy. Candida guilliermondii, a rare human pathogen, was resistant to medical therapy in this case.

Research in training clinics: a bridge between science and practice

Clinics associated with psychology training programs have potential to generate important research data. The expectation that research be experimental in nature has limited the pursuit of research in training clinics. This type of efficacy study is not feasible in most clinics, where too much variation occurs as a result of training and administrative demands. Numerous process-outcome studies have been effectively conducted in training clinics. This article reviews some of these studies, identifies problems related to research in training clinics, and makes recommendations for the development of an enhanced research agenda for training clinics.

Escape protein supplementation of steers fed grass silage-based diets

Beef steers (Trials 1 and 2, 280 +/- 2 kg; Trial 3, 330 +/- 2 kg) were fed diets of 67.5% wheat (Trial 1) or oat silage (Trials 2 and 3), 20.5% barley, and 12% supplement in randomized complete block design growth trials. Dietary treatments were graded levels of supplemental escape protein (EP) from corn gluten meal (Trial 1, 0 to 213 g/d escape protein) or animal by-products (1:1:1 DM mixture of blood, feather, and meat and bone meals, 0 to 223 or 0 to 317 g/d of escape protein in Trials 2 and 3, respectively) to titrate amounts needed to maximize steer live weight gain. As supplemental EP from corn gluten meal increased, steer live weight gain increased linearly (P < .001) and feed-to-gain decreased linearly (P < .001). Supplementation with 135 g/d of corn gluten meal EP (335 g/d of corn gluten meal) increased average daily gain from .76 to .91 kg/d. As supplemental EP from animal by-products increased, steer live weight gain increased quadratically (P < .05) and feed-to-gain decreased linearly (P < .01). Supplementation with 223 or 317 g/d of animal by-product EP increased live weight gain by .27 kg/d. Supplemental escape protein was needed to increase live weight gain of steers consuming ensiled forage diets due to low EP contents of silages (7, 3, and 23% of CP in Trials 1, 2, and 3, respectively) and barley (15, 27, and 22% of CP in Trials 1, 2, and 3, respectively) and limited microbial protein synthesis.

Torsion of the tendon of peroneus brevis

The authors present a previously undescribed torsion located within the tendon of peroneus brevis. The musculotendinous unit of peroneus brevis was isolated from 46 lower extremities of cadavers. A goniometer was constructed and utilized to quantify the degree of torsion located within each peroneus brevis tendon. Torsion was present in all 46 cadaver specimens, with a mean of 38.5 degrees and a range of 26 degrees to 56 degrees. The regional anatomy and biomechanical functions of peroneus brevis are discussed, and proposed bases for the embryologic origins and functional significance of the torsion are presented.

Ruminal undegradability of blood meal and effects of blood meal on ruminal and postruminal digestion in steers consuming vegetative orchardgrass hay

Four crossbred steers (360 +/- 3 kg) cannulated at the rumen and duodenum were used in a 4 x 4 Latin square design to examine the effects of supplemental blood meal (BM) on voluntary intake, digesta kinetics, ruminal fermentation, site and extent of digestion, and bacterial protein synthesis in steers fed vegetative orchardgrass hay (Dactylis glomerata L.). The levels of BM supplementation were 0, .07, .13, and .20 kg/d. Voluntary intake of OM (8.35 kg/d) was not significantly affected by BM supplementation. No significant effects of BM supplementation were detected for OM flow to the duodenum or digestion in the rumen or lower tract. However, total tract OM digestibility decreased 2.2 percentage units at .20 kg/d of BM intake (lower with vs without BM; P < .10). Total N intake and flow to the duodenum linearly increased (P < .10) with increasing BM level from 251 to 277 g/d and from 158 to 199 g/d, respectively. Ammonia N and bacterial N flows to the duodenum were not affected (P > .10) by BM supplementation. As a result, nonammonia N flow to the duodenum increased linearly (P < .10) with increasing BM supplementation. Ruminal escape N from BM was 83.5, 85.3, and 87.2% for .07, .13, and .20 kg/d of BM, respectively. Apparent bacterial efficiency and true bacterial efficiency were not affected (P > .10) by BM supplementation. Total amino acid and total essential amino acid flows to the duodenum were increased (P < .10) by dietary inclusion of BM. Duodenal flows of all essential amino acids except lysine and valine and of all nonessential amino acids except alanine and proline were increased (P < .10) by BM inclusion in the diet. In summary, supplementation with BM increased ruminal escape N and duodenal flows of total and most essential amino acids.

Dynamic imaging of structural changes in silver catalysts by environmental scanning electron microscopy

Polycrystalline silver catalysts are used extensively for the partial oxidation of methanol to formaldehyde, which is then primarily incorporated in the synthesis process for adhesives and resins. In order to maximize formaldehyde production it is essential to gain a comprehensive understanding of the complex microstructural changes which occur in the catalyst during reaction conditions. However, conventional electron microscopic techniques are incapable of imaging catalysts at high temperatures and in the presence of a gaseous atmosphere. Therefore, an environmental scanning electron microscope (ESEM) has been used to image polycrystalline silver catalysts during simulated industrial conditions. The most dramatic effect of heating various catalysts to 700 degrees C in the ESEM chamber was the formation of "pinholes" in the silver surface. These "pinholes" occur at specific temperatures and are inherently associated with the catalytic process, resulting from near-surface explosions caused by subsurface hydroxyl recombination. Of particular interest was the nature and location of the holes, which preferentially occur in the vicinity of surface defects such as platelets and edge structures. To the best of our knowledge, this study represents the first time that the progress of a catalytic reaction has been observed under in situ conditions by scanning electron microscopy.

Differential stimulation of cortisol and dehydroepiandrosterone levels by food in obese and normal subjects: relation to body fat distribution

BACKGROUND

It has been previously shown that food intake elevates circulating ACTH and cortisol levels, but no report has been published regarding the changes in circulating dehydroepiandrosterone (DHEA). DHEA was originally described as a weak androgen, but more recently it has been associated with a wide range of metabolic functions. In addition, previous studies have described a hyper-responsive hypothalamo-pituitary-adrenal axis in obese subjects in response to various stimuli, but the specific response to food has not been studied.

SUBJECTS AND DESIGN

We studied the effect of food on the hypothalamo-pituitary-adrenal axis in 20 subjects of normal body mass index (BMI range 18-25) and also in a group of 12 obese subjects (BMI range 34-61). Levels of glucose, insulin, ACTH, cortisol and dehydroepiandrosterone were measured every 20 minutes.

RESULTS

A small rise in DHEA accompanies the rise in circulating ACTH and cortisol in response to food in both lean and obese subjects, but DHEA rose independently of cortisol and ACTH on the fasting day. In the obese subjects, food induced a significantly greater change in serum cortisol (peak cortisol rise (mean +/- SEM); normal-weight group, 169 +/- 14%; obese group, 294 +/- 23%) and in the cortisol/DHEA ratio (area under the curve; normal-weight group, 202 +/- 15%; obese group, 292 +/- 29%) than in the normal-weight subjects. This difference was particularly notable in those with central-type obesity (waist/hip ratio > 0.80). A group of the normal, jean female subjects showed no cortisol rise after food intake.

CONCLUSION

Our results suggest that DHEA may vary independently of circulating cortisol, and that the cortisol response to food is enhanced in obese subjects, particularly in those with central obesity. We speculate that there may be a caused connection between the cortisol response to food in normal subjects, and the subsequent distribution of fat if such subjects overeat sufficiently to become obese.

Effect of storage temperature and time on fiber content of fresh and ensiled alfalfa

To determine effects of storage temperature and time on fiber content, fresh alfalfa (late vegetative) was hand-clipped from three locations (blocks) and stored fresh or ensiled at -20 degrees C or +60 degrees C for 0, 24, 48, 96, 168, or 336 h. The experimental design was a randomized complete block with a 2 x 2 factorial arrangement of treatments. Main effects were method of forage conservation (fresh or ensiled) and temperature of storage (-20 degrees C or + 60 degrees C). Length of storage (0, 24, 48, 96, 168, or 336 h) was in the subplot. Conservation method x storage temperature x time interactions were detected (P < .05) for NDF, IVDMD, ADIN, and N content of NDF. Large increases in alfalfa NDF were observed up to 168 h of storage at 60 degrees C, whereas when fresh alfalfa was stored at -20 degrees C, small increases were observed up to 48 h but a large increase was observed after 168 h. Ensiled alfalfa stored at -20 degrees C had no change in NDF content. Contributors to increased NDF seemed due to changes in protein solubility and glycosylamine formation when fresh forage was stored at 60 degrees C, and changes in protein solubility, glycosylamine formation, and Maillard product formation when ensiled forage was stored at 60 degrees C. At -20 degrees C, formation of adducts with arabinose and glucose from nonstructural carbohydrates as well as polymerization and fragmentation of cell wall monosaccharides probably contributed to altered NDF content of alfalfa.

Health care worker incidents reported in a rural health care facility: a descriptive study

About eight million workers, or 6.4% of the total United States work force, are employed by the health care industry. Frequency of injury has continued to rise from 6 per 100 full time workers in 1980 to over 10 in 1992 (US Department of Labor, 1994). This descriptive, retrospective study characterizes host, agent, and environmental variables for 120 incidents reported in 1990 at a rural nursing home and acute care hospital with 290 employees. Incident is defined as an event that results in injury or has the potential to result in an injury. Based on an estimate of full time equivalents (190.4 FTE) calculated at 9 months, the incident rate per 100 FTEs was 63 for this facility. Injury was reported in 114 incidents, resulting in an overall injury rate per 100 FTEs of 59.9. Sprains and strains were the most frequently reported nature of injury followed by cuts, lacerations, and punctures. Female and male workers reported similar proportions of incidents. At midyear, 85% of the employee population was female, 15% male. Females represented 83.3% of the subjects reporting incidents; males represented 16.7%. These data from a small rural facility differ from many of the findings on the injury experience of health care workers reported in the literature.

Eating behavior in bulimia nervosa: multiple meal analyses

Ten bulimic individuals were admitted to an inpatient unit and for 7 consecutive days eating behavior was observed and recorded. Age, sex, and weight-matched control subjects (n = 10) were admitted to the same unit for 4 d. All food and fluid intake, frequency of binge eating and purging, and ratings of appetite and mood before and after eating were recorded every 24 h. Bulimic patients demonstrated chaotic eating patterns that varied within as well as between individuals. Total daily energy intake was significantly higher for bulimic patients (41982 +/- 113 kJ; 10,034 +/- 2701 kcal) than for control subjects (8050 +/- 0427 kJ; 1924 +/- 102 kcal). On average, patients binged 1.6 times, purged three times, and ate one snack or meal without purging daily. Macronutrient analyses of intake revealed significantly less energy from protein and more energy from fat in bulimic patients compared with control subjects. Some improvement of mood was noted after binges, the magnitude of which was greatest after purging.

Molecular requirements for the inhibition of the tetracycline antiport protein and the effect of potent inhibitors on the growth of tetracycline-resistant bacteria

Forty-seven compounds and tetracycline (Tc) structural analogues were tested for their ability to interfere with [3H]Tc uptake in everted inner membrane vesicles derived from Tc-resistant Escherichia coli D1-209, bearing the class B tetracycline resistance efflux protein (Tet protein). For effective inhibition of Tc uptake, the molecule had to have an intact ABCD tetracyclic carbon skeleton and a conjugated phenolic beta-diketone substructure at positions 10-12a with the subsequent development of keto-enol tautomerization. Molecular variations at carbon positions 2, 4, 5, 6, 7, 8, and 9 did not decrease, and some increased, the inhibitory activity as compared to that of Tc. Among these compounds, the highest inhibition of uptake occurred with certain position 6 and 13 derivatives of 5-hydroxytetracycline. In a group of 13-(propylthio) derivatives of 5-OH-Tc [13-propyl, 13-(3-chloropropyl), and 13-(2-carboxyethyl)] there was a correlation between uptake inhibitory activity and antibacterial activity. The 13-(3-chloropropyl) derivative, with the best efflux inhibitory activity, exhibited synergistic activity when tested in combination with doxycycline against Tc-resistant E. coli bearing the class A or B determinant, against Staphylococcus aureus bearing class K, and against Enterococcus faecalis bearing the class L determinant. The 13-propyl analogue also showed high transport blocking activity and showed synergistic antibacterial activity against E. coli bearing the class A determinant and additive activity against the other Tc-resistant bacteria. The synergistic antibacterial activity of these compounds was not shown by the 13-[(2-carboxyethyl)thio] homologue, whose efflux blocking activity was 70-fold less. These findings suggest that multiple sites on the Tc molecule are available for synthetic modification toward the development of an effective Tc blocking agent. Such compounds, used alone or in combination with a standard tetracycline, show improved antibacterial activity.

The pharmacokinetics and pharmacodynamics of medifoxamine after oral administration in healthy elderly volunteers

The pharmacokinetics and psychomotor effects of medifoxamine, a 5 HT reuptake inhibitory antidepressant, were studied in healthy elderly volunteers after single and multiple dosing. The elimination half life (t1/2z) after single doses of 300 mg was 2.8 h--almost identical to that found in young volunteers. After seven days of dosing at 100 mg three times daily the mean corrected AUC after 300 mg significantly increased from 1.04 to 1.34 mg.h.l-1 and t1/2z increased to 4.0 h (NS). There were no significant changes in critical flicker fusion frequency, symbol digit substitution, continuous attention or choice reaction times.

Inhibition of the tetracycline efflux antiport protein by 13-thio-substituted 5-hydroxy-6-deoxytetracyclines

A series of 13-(alkylthio) and 13-(arylthio) derivatives of 5-hydroxy-6-deoxytetracycline (tetracycline, Tc) were synthesized and compared to the clinically used antibiotics tetracycline, methacycline, and minocycline for their ability to inhibit tetracycline efflux in an everted membrane vesicle assay of bacterial resistance to tetracyclines. The assay screened for the ability of tetracycline analogues to inhibit [3H]tetracycline uptake into everted membrane vesicles, thereby evaluating the molecular prerequisites for inhibition of an efflux-dependent resistant bacterial system. Thiol adducts attached at the exocyclic C13 carbon of methacycline led to an increase in inhibitor potency as compared to the reference antibiotics. The most potent inhibitors of [3H]tetracycline uptake into everted vesicles among these analogues, particularly members of the alkyl series, revealed important structure-activity relationships between inhibitor potency, steric parameters, and lipophilicity at the C13 sulfur position.

Eating pathology in bulimia nervosa

Degree of eating pathology in bulimia nervosa was assessed using the Eating Behavior Rating Scale (EBRS) across three videotaped eating sessions. Twelve bulimic and 12 non-eating disordered subjects participated in this study. All subjects were filmed during a baseline meal (ad libitum), a high-calorie meal, and a low-calorie meal (both fixed amounts). Mean EBRS scores were significantly higher for bulimics (12.6 +/- 1.7) than for controls (3.9 +/- 0.9), suggesting a higher degree of eating pathology in these patients. Affect during eating was significantly more negative in the bulimic patients. EBRS and affect scores were significantly correlated [r (11) = .813, p < .01]. Bulimics had a slower rate of eating than controls and took significantly longer to initiate eating. Scores of pathological eating correlated with scores on the Eating Attitudes Test and the Bulimic Investigatory Test-Edinburgh, indicating a relationship between objective measures of pathological eating and self-report measures of eating disorder symptoms.

The association of age with gastric emptying

Gastric emptying is important as a rate-limiting step in the absorption of orally administered drugs. Paracetamol absorption kinetics were used to compare gastric emptying in 19 fit elderly and 19 fit young volunteers. The results showed no significant difference in any of the derived parameters (t1/2abs, tlag and tmax) between the two groups. These results suggest that ageing does not impair this rate-limiting step in drug absorption.

Observation of the anterior supracostal muscles

A pair of anomalous supernumerary muscles has been found in a single cadaver which fit the classic description of the Musculus supracostalis anterior. The muscles took origin from the first rib deep to the two pectoral muscles and between the origins of the pectoralis minor and serratus anterior muscles. They were directed inferiorly to insert on the upper margin of the fourth rib. The nerve supply of one muscle of the pair was determined to be from the collateral branch of the second right intercostal nerve. This supports the theory that these rare muscles may be derived from a single external intercostal muscle which grew to span several intercostal spaces.

Decrease in resting metabolic rate during abstinence from bulimic behavior

Among eight normal-weight bulimic women studied during 1 week of binge eating and vomiting and 7 weeks of abstinence without weight loss, resting metabolic rate and T3 and T4 levels fell significantly during abstinence. These data suggest that a physiological consequence of binge eating and vomiting is an increase in metabolic rate, in part due to increased thyroid hormone activity.

Effects of rapeseed silage variety and dietary level on digestion and growth performance of beef steers

A digestion and ruminal fermentation trial involving five ruminally cannulated steers assigned to a 5 x 5 Latin square with a 2 x 2 + 1 arrangement of dietary treatments was conducted to evaluate the effects of variety of rapeseed silage (RS) containing either a high (HG) or a low (LG) glucosinolate concentration when fed at 100 or 50% of diet DM. A bromegrass hay-corn-soybean meal mixture, which was expected to be isocaloric and isonitrogenous with the RS, was used as the control (C) treatment and replaced RS in the 50% diets. In situ disappearance of substrate from both RS varieties was measured in ruminal environments created by each diet. No dietary treatment x RS substrate interactions were observed for any in situ variable. Total tract digestibility and extent of in situ disappearance of both DM and NDF were greater (P less than .01) for HG than for LG. In situ DM and NDF disappearance at 8, 16 and 24 h was greater (P less than .01) for RS than for the C diet. Similarly, total tract DM digestibility was greater (P less than .01) for RS (61.0%) vs C (56.0%) diets. Diets with 50% RS had greater (P less than .01) NDF digestibility (50.4%) than 100% RS (43.6%) diets. Variety of RS had no effect on particulate passage rate. In a 77-d growth trial with 60 beef steers, ADG was greater (P less than .01) for HG vs LG (.46 vs .36 kg), 50 vs 100% (.52 vs .31) and C vs RS (.64 vs .41) diets.(ABSTRACT TRUNCATED AT 250 WORDS)