Association between consumption of nonessential energy-dense food and body mass index among Mexican school-aged children: A prospective cohort study

BACKGROUND/OBJECTIVES

Obesity prevalence in Mexican children has increased rapidly and is among the highest in the world. We aimed to estimate the longitudinal association between nonessential energy-dense food (NEDF) consumption and body mass index (BMI) in school-aged children 5 to 11 years, using a cohort study with 6 years of follow-up.

SUBJECTS/METHODS

We studied the offspring of women in the Prenatal omega-3 fatty acid supplementation, child growth, and development (POSGRAD) cohort study. NEDF were classified into four main groups: chips and popcorn, sweet bakery products, non-cereal based sweets, and ready-to-eat cereals. We fitted fixed effects models to assess the association between change in 418.6 kJ (100 kcal) of NEDF consumption and changes in BMI.

RESULTS

Between 5 and 11 years, children increased their consumption of NEDF by 225 kJ/day (53.9 kcal/day). In fully adjusted models, we found that change in total NEDF was not associated with change in children's BMI (0.033 kg/m2, [p=0.246]). However, BMI increased 0.078 kg/m2 for every 418.6 kJ/day (100 kcal/day) of sweet bakery products (p=0.035) in fully adjusted models. For chips and popcorn, BMI increased 0.208 kg/m2 (p=0.035), yet, the association was attenuated after adjustment (p=0.303).

CONCLUSIONS

Changes in total NEDF consumption were not associated with changes in BMI in children. However, increases in the consumption of sweet bakery products were associated with BMI gain. NEDF are widely recognized as providing poor nutrition yet, their impact in Mexican children BMI seems to be heterogeneous.

Doxycycline-induced cholestatic liver injury

Doxycycline-induced liver injury is a rare phenomenon, with an unclear clinical course and etiopathogenesis. The onset of injury may be acute-to-subacute, with a pattern ranging from hepatocellular or cholestatic to mixed, and it often lasts up to several weeks. We present a case of cholestatic liver injury secondary to doxycycline use in a middle-aged woman. In patients with a history of doxycycline exposure and subsequent hepatic injury, an adverse drug reaction due to doxycycline should remain on the differential, and immediate removal of the offending agent with close monitoring of the clinical condition should be pursued.

Trainee colonoscopy quality is influenced by the independent and unobserved performance characteristics of supervising physicians

Background  Endoscopy training remains an apprenticeship, and the characteristics that facilitate transfer of high quality procedural skills from role models to trainees are unknown. We sought to determine whether unobserved supervisor performance influences the quality of colonoscopy performed by trainees, by studying how supervisors perform alone and how trainees perform while under those same supervisors. Methods  This was a retrospective cross-sectional study conducted among ambulatory adults ≥ 50 years old who underwent colonoscopy for cancer screening or polyp surveillance from 2006 to 2015 at one academic medical center. The primary exposures were the colonoscopy withdrawal time (WT) and adenoma detection rate (ADR) of supervisors while performing colonoscopies alone. The primary outcomes were the WT and ADR of trainees performing colonoscopies under supervision. Results  Data were included from 22 attending gastroenterologist supervisors, 56 gastroenterology fellow trainees, and 2777 adults undergoing 3094 colonoscopy procedures. Among all supervised colonoscopies, mean trainee WT was 12.7 minutes (SD 4.9) and trainee ADR was 33.5 %. The trainee WT was 0.42 minutes longer (standard error = 0.16, P  = 0.01) per minute increase in supervisor WT. Similarly, trainee ADR was higher under a high ADR supervisor, and the odds ratio of high compared to low supervisor ADR category was 1.28 (95 %CI 1.01 - 1.62, P  = 0.04) after adjusting for other factors. Conclusions  The unobserved performance characteristics of supervising endoscopists may influence the quality of colonoscopy performed by trainees.

Erfahrungen mit einem Thromboplastin auf der Basis von rekombinantem Gewebefaktor und synthetischen Phospholipiden

Rekombinanter Gewebefaktor wurde mit synthetischen Phospholipiden lipidiert und daraus ein Thromboplastinreagenz hergestellt (Innovin™, Baxter Diagnostics). Bisherige Erfahrungen zeigen folgendes: sehr niedrige VK-Werte auf verschiedenen Geräten; ISI-Werte sind wie bei konventionellen Reagenzien gerätespezifisch; hohe Faktorenempfindlichkeit, insbesondere bei mittelschweren und schweren Mängeln; gute Plausibilität im Vergleich von TPZ und Faktorenspiegeln, auch in Gegenwart von Heparin; sehr gute Vergleichbarkeit bei Patienten mit oraler Antikoagulation im Vergleich zu BCT/253, Thrombotest™, Hepatoquick® und anderen sensitiven Reagenzien; gelegentlich ein Trend zu höheren INR-Werten gegenüber einigen anderen Thromboplastinen bei Patienten mit INR-Werten >3 und relativ niedrigen Werten von insbesondere Faktor VII und Faktor X; Vorteile in der Bestimmung der Einzelfaktoren durch stark gespreizte Bezugskurven; Anwendung im Kapillarblut ist möglich; sehr gute Chargenkonstanz.

Limited usefulness of endoscopic evaluation in patients with continuous-flow left ventricular assist devices and gastrointestinal bleeding

BACKGROUND

Gastrointestinal bleeding (GIB) is a frequent cause of re-admission in patients with continuous-flow left ventricular assist devices (CF-LVADs) and is associated with multiple endoscopic procedures and high resource utilization. Our aim was to determine the diagnostic and therapeutic yield of endoscopy and to develop a more cost-effective approach for the management of GIB in CF-LVAD recipients.

METHODS

We retrospectively reviewed 428 patients implanted with a CF-LVAD between 2009 and 2016 at the Columbia University Medical Center and identified those hospitalized for GIB. Patients were categorized into upper GIB (UGIB), lower GIB (LGIB) and occult GIB (OGIB), based on clinical presentation.

RESULTS

Eighty-seven CF-LVAD patients underwent a total of 164 GIBs, resulting in 239 endoscopies. Index presentation was consistent with UGIB in 30 (34.5%), LGIB in 19 (21.8%) and OGIB in 38 (43.7%) patients. On the first GIB, 147 endoscopies localized a bleeding source in 49 (30%), resulting in 24 (16.3%) endoscopic interventions. Of 45 lesions identified, arteriovenous malformations (AVMs) were the most common (22, 48.9%). A gastric or small bowel source (HR 2.8, p = 0.003) and an endoscopic intervention (HR 1.9, p = 0.04) predicted recurrent GIB. The proposed algorithm may reduce the number of endoscopic procedures by 45% and costs by 35%.

CONCLUSIONS

Occult GIB is the most common presentation in CF-LVAD patients and carries the lowest diagnostic and therapeutic yield of endoscopy. Performing an intervention was among the strongest predictors of recurrent GIB. Our proposed algorithm may decrease the number of low-yield procedures and improve resource utilization.

Language and therapeutic change: a speech acts analysis

Drawing on the speech acts theory, a linguistic pattern was identified that could be expected to be associated to therapeutic change, characterized by being uttered in the first person singular and present indicative, and by being self-referential in its propositional content. The frequency of the pattern was examined among verbalizations defined as change moments in three therapies with different theoretical orientation. Results show that the majority of change moments have the specified pattern, and that this pattern is significantly more frequent in change moments than in random non-change-related verbalizations, and so, it does not pertain to therapeutic conversation in general. Implications are discussed concerning the possibility of using the linguistic pattern as an additional and complementary criterion in the identification of moments of change in the therapeutic process.

Experimental and modeling investigations of a hybrid upflow anaerobic sludge-filter bed (UASFB) reactor

A 9.8-L hybrid UASFB reactor, in which the lower half was occupied by a sludge blanket and the upper half by small floating polyethylene media, was evaluated using wine distillery vinasse as substrate. The reactor was operated for a total period of 232 days at 33 + 1 degrees C. Continuous feeding of the reactor was started with an initial OLR of 2.9 g COD/L.d and then it was increased step wise to 19.5 g COD/L.d by increasing the feed COD, while maintaining a constant HRT (1.05 d). The reactor was equipped with a continuous internal recirculation system from top to the bottom at the rate of 9 L/h (upflow velocity = 0.83 m/h) upto day 159 and then it was reduced to about half on day 160 onwards. It was observed that the reduced recirculation rate did not affect the performance of the reactor with an average COD(t) and COD(s) removal efficiencies of 82 and 88%, respectively. A maximum gas production rate of 6.7 L CH(4)/L(reactor).d was achieved for the highest OLR applied. The specific activity analysis depicts that the activity of the attached biomass was more than 2 times higher than that of the granular sludge. The efficiency of liquid mixing was good through out this study. The packing medium had a dual role in the retention of the biomass inside the reactor: i.e. entrapment of biomass within the support and filtration of the granular biomass, preventing it from going out of the reactor. ADM1_10 model simulated well the dynamic evolutions of the main variables in the liquid as well as in the gas phases.

Modeling microbial diversity in anaerobic digestion

The aim of this study is to develop a modeling approach able to handle microbial diversity both in normal and abnormal situations. Normal situations are defined as changing input characteristics that do not imply process imbalance while abnormal situations are illustrated by the presence of toxicant into the reactor. In both cases, modeling is performed by adding a stochastic term on top of a well defined and well structured model such as the IWA Anaerobic Digestion Model No1. Experimental data from a 1 m3 pilot scale anaerobic digester treating wine distillery wastewater are provided to demonstrate the applicability of this approach. Discussion also highlights that monitoring of digesters might receive a renewed consideration in the near future in order to handle explicitly microbial diversity within the control objectives.

Amino acid intake during lactation and amino acids of plasma and human milk

The aim of this study was to determine the free amino acid pool in plasma and milk in marginally nourished lactating women. Twenty-eight rural women (age, 23.9+/-5y; weight 50.2+/-4.9 kg; height, 148.2+/-4.8 cm) were studied under metabolic balance conditions. Subjects were divided into 6 groups (5-6 women in each), representing rural mothers postweaning and in the 15, 3rd, and 6th months of lactation; nonpregnant, nonlactating controls were from rural and urban areas. Amino acid analyses of diet and of plasma and milk samples were performed using a Beckman 6300 amino acid analyzer. Lysine intakes were lower than the recommended intake for lactating women (RDA). Plasma amino acid profiles differed between the lactating and weaned groups: aspartate and isoleucine increased at the 6th month (P < 0.05), while valine declined over weaning time (P < 0.05). In milk, valine and proline decreased at the 6th month (P < 0.05), while serine rose at the 3rd month. Free amino acid pools were 1- to 15-fold higher in plasma than in milk for branched-chain amino acids and basic, aromatic, and neutral amino acids. In mammary tissue these amino acids can be channeled to tissue and milk protein synthesis or to catabolic pathways. Glutamate was 40-fold higher in milk with respect to plasma content. This was the predominant amino acid in the free amino acid pool in milk. These results suggest selective amino acid transport in mammary tissue during lactation.

Perceptual analysis in different voice samples: agreement and reliability

The objective of this study was to estimate the agreement and reliability of voice evaluation by a group of expert listeners using the central portion of a sustained vowel and a fragment of connected speech as voice samples. Ratings were made using Wilson's Buffalo III Voice Screening Profile. Analysis showed that intraindividual listeners' agreement presented variability in the evaluation of both voice samples. In the evaluation of the central portion of the sustained vowel, interindividual listener agreement was moderate for breathiness, hyponasal resonance, and overall voice rating; in connected speech, agreement was moderate for most voice qualities (breathy, rough, high/low pitch, and hyponasal resonance). Finally, Wilson's Buffalo III Voice Screening Profile presented good reliability values for both voice samples, with overall voice rating achieving higher values (.90) than any other voice-quality variable.

Pilot studies of species-specific chemotherapy of childhood acute lymphoblastic leukemia using genotype and immunophenotype

Genotype and immunophenotype can be used to define biological species of acute lymphoblastic leukemia (ALL). The purpose of these two pilot studies, conducted between 1986 and 1994, was to explore the feasibility and acceptability of classifying ALL in this manner for selection of treatment rather than using conventional risk for failure factors such as age and initial white blood cell count. The possibility that conventional risk factors would be overcome and survival improved by this approach was also considered. Flow cytometry and chromosome analysis were used to classify the ALL of 150 children into one of five biologic categories as defined by cell surface antigens, DNA index and chromosome number and arrangement. Chemotherapy regimens depended on the assigned category. There was no provision for cranial irradiation and use of alkylating agents, anthracyclines and epipodophyllotoxins was restricted in order to reduce risk of late adverse sequelae. All patients are included in the analysis regardless of presenting condition or adherence to protocol. The majority of patients were Mexican-American or African-American. Eight-year event-free survival (EFS) is 60.7% (+/-4%) and 8-year overall survival (OAS) 72.6% (+/-3.7%). EFS and OAS varied significantly among the biologic categories despite differences in chemotherapy regimens. When the patients with B-precursor ALL were retrospectively classified by current Pediatric Oncology Group (POG) criteria, 8-year EFS was 82% (+/-7.3%) for the good risk group, 68.9% (+/-5.9%) for the standard risk and 48.8% (+/-7.6%) for the poor risk, all significant differences. However, when retrospectively classified according to the Rome/NCI prognostic criteria the 8-year EFS for standard risk patients was 69.1% (+/-5.1%) and for high risk 58.8% (+/-6.9%), not a statistically significant difference. Numbers of T cell and B cell patients are too few for comparison. Gender and ethnicity influenced survival as in treatment based on prognostic factors. Initial central nervous system (CNS) relapse occurred in five patients (3%) and combined CNS and hematological relapse in six (3%). Factors significantly associated with CNS and combined relapse were leukemic pleocytosis in the initial CSF sample, pro-B immunophenotype and DNA index <1.16, but not initial white blood cell count. Only three survivors appear to have serious late adverse sequelae, the only neurologic the result of asparaginase-induced cortical vein thrombosis. The results suggest that use of biologic species as defined by immunophenotype and genotype to select therapy of ALL is feasible and acceptable but under the conditions of these studies offered no apparent therapeutic advantage over conventional risk grouping. However, the introduction of molecular genotyping and novel gene targeted therapeutic agents justify further exploration of this approach.

Fatty acid oxidation affects food intake by altering hepatic energy status

Inhibition of fatty acid oxidation stimulates feeding behavior in rats. To determine whether a decrease in hepatic fatty acid oxidation triggers this behavioral response, we compared the effects of different doses of methyl palmoxirate (MP), an inhibitor of fatty acid oxidation, on food intake with those on in vivo and in vitro liver and muscle metabolism. Administration of 1 mg/kg MP selectively decreased hepatic fatty acid oxidation but did not stimulate food intake. In contrast, feeding behavior increased in rats given 5 or 10 mg/kg MP, which inhibited hepatic fatty acid oxidation to the same extent as did the low dose but in addition suppressed fatty acid oxidation in muscle and produced a marked depletion of liver glycogen. Dose-related increases in food intake tracked dose-related reductions in liver ATP content, ATP-to-ADP ratio, and phosphorylation potential. The findings suggest that a decrease in hepatic fatty acid oxidation can stimulate feeding behavior by reducing hepatic energy production.

Inhibition of wound-induced accumulation of allene oxide synthase transcripts in flax leaves by aspirin and salicylic acid

Allene oxide synthase (AOS) mediates the conversion of lipoxygenase-derived fatty acid hydroperoxides to unstable allene epoxides, which supply the precursors for the synthesis of the phytohormone jasmonic acid (JA). In this study the characterization of AOS gene expression in flax (Linum usitatissimum) is reported. AOS was constitutively expressed in different organs of flax plants. Additionally, AOS gene expression was enhanced after mechanical wounding in both the directly damaged leaves and in the systemic tissue located distal to the treated leaves. This wound-induced accumulation of AOS required the de novo biosynthesis of other unknown proteins involved in the signaling pathway modulating wound-induced AOS gene expression. Furthermore, the wound-induced AOS mRNA accumulation was correlated with the increase in the levels of JA. Both JA and its precursor, 12-oxo-phytodienoic acid, activated AOS gene expression in a dose-dependent manner. Thus, JA could activate its own biosynthetic pathway in flax leaves. Moreover, neither salicylic acid (SA) nor aspirin influenced AOS enzymatic activity. It is interesting that pretreatment with SA or aspirin inhibited wound-induced accumulation of AOS transcripts. These results suggest that a potent inhibition of JA biosynthetic capacity in leaves can be affected by SA or aspirin at the level of AOS gene expression.

Satiety from fat? Adverse effects of intestinal infusion of sodium oleate

To determine whether damage to the intestinal mucosa by oleic acid causes the suppression of food intake observed in response to intraintestinal infusion of the fatty acid, we measured lactate dehydrogenase (LDH) activity, a marker for cell damage, in the intestinal lumen after intestinal infusion of fatty acid under conditions similar to those employed in studies of eating behavior. Infusions of 25 or 51 mM sodium oleate (neutralized oleic acid) markedly and rapidly increased LDH activity, whereas infusions of saline had little or no effect. Infusion of octanoate, which has been reported to be ineffective in reducing eating behavior, did not increase intestinal LDH activity relative to saline infusion. Similarly, infusion of ethyl oleate or free (nonneutralized) oleic acid neither increased luminal LDH activity nor suppressed food intake. Infusion of sodium oleate also produced a strong conditioned aversion to sucrose. The results strongly suggest that the suppression of food intake induced by intraintestinal infusion of sodium oleate is due to the injurious effects of this unphysiological form of the fatty acid.

Intragastric carbohydrate exerts both intake-stimulating and intake-suppressing effects

Ingestion-contingent infusions of 6% carbohydrate did not affect saccharin intake during the first ingestive bout, but later they greatly stimulated ingestion, slowed the rate of decline of ingestion during bouts, and increased the average bout size. This suggests that the intake-stimulating effect of carbohydrate infusions is partly attributable to conditioned desatiation. Satiation can also be conditioned because more concentrated infusions (24% carbohydrate) did not increase daily intake or average bout size, even though both concentrations stimulated ingestion during the first 0.5-6.0 min of a test session, as well as during extinction tests when only water was infused. Increased intake may be partly mediated by a hedonic mechanism because naloxone, an opioid antagonist, decreased intake in rats infused with carbohydrate to a greater degree than it decreased intake in rats infused with water.

Stimulation of fluid intake by nutrients: oil is less effective than carbohydrate

It has been thought that the ability of nutrients to reinforce ingestion is related to their ability to provide metabolizable energy. This implies that the reinforcing effect of carbohydrate should be similar to that of fat. To test this concept, rats were trained in an apparatus that infused water or nutritive solutions/suspensions into their stomachs every time they drank a sapid solution. Each training trial lasted for 1 day. Successive training trials were interspersed by 1-day periods in which the rats were infused with plain water and offered plain water or a tastant different from the training taste (i.e., taste paired with vehicle infusion). Three different sapid solutions were used: a sweet solution (saccharin), a nonsweet solution (NaCl), and a mixture of sweet and nonsweet. Starch or maltodextrin infusions strongly and consistently stimulated intake of these solutions. Oil infusions also significantly stimulated intake, but feebly and less consistently. Indeed, in the one experiment in which the only sapid fluid offered was saccharin, oil infusions had no significant effect. Two different oil suspensions (one fine and one coarse) were equally ineffective in stimulating saccharin intake. To determine whether some unsuspected flaw in the infusion experiments somehow produced invalid results, an additional experiment was conducted in which rats ingested starch or oil suspensions by mouth. Consistent with the infusion experiments, starch stimulated ingestion to a much greater degree than did oil. It is concluded that intragastric infusion of triglyceride oil is a less potent reinforcer of ingestion than is equicaloric infusion of carbohydrate.

High-dose mercaptopurine and intermediate-dose cytarabine during first remission of acute myeloid leukemia

High-dose, continuous infusion of intravenous mercaptopurine (HD 6MP) followed by intermediate-dose continuous cytarabine (ID Ara-C) has been shown to produce remissions in children with relapsed acute myeloid leukemia (AML). The purpose of this pilot study was to explore the feasibility of using this drug regimen as a component of treatment during the first remission of AML. Of 17 children with newly diagnosed AML registered in the study, 14 developed complete remission on conventional induction therapy and subsequently received the HD 6MP and ID Ara-C combination. The dosages of HD 6MP were escalated from 500 mg/m2 to 1250 mg/m2 in 24-hr infusions. The initial dosages of ID Ara-C were escalated from 250 mg/m2 to 650 mg/m2/24 hr and from 1 day to 4 days. Conventional treatment for AML was administered simultaneously. Seven of the 14 children remain in initial complete remission for 15 to 46 months and have completed treatment. Severe pancytopenia was observed in all patients, but there were no toxic deaths and no deaths during remission. The inclusion of HD 6MP and ID Ara-C in the treatment of AML in first remission appears to be feasible. Evaluation of its efficacy will require a comparative clinical trial.

Is fructose sweeter than glucose for rats?

Because it is generally thought that the intensity of the taste of fructose is greater than that of glucose for rats, it seemed surprising when sham-fed rats drank substantially less of a mixture of 6% fructose plus saccharin than of a mixture of 6% glucose plus saccharin. At least 3 different factors contribute to this effect. First, the taste of fructose is less attractive to rats than is the taste of glucose; sham-fed rats strongly preferred glucose over fructose (no saccharin was used in this experiment). The second factor is experience. Rats having substantial previous experience with glucose, but not with fructose, consistently preferred glucose over fructose. Conversely, rats having substantial previous experience with fructose, but not with glucose, initially showed no consistent preference but subsequently tended to prefer glucose. The third factor is an interaction between saccharin and the type of sugar. Rats given only one solution at a time drink approximately as much fructose as glucose when the solutions contain no saccharin. The addition of 0.25% saccharin to 6% glucose stimulated intake, whereas the addition of the same amount of saccharin to 6% fructose did not stimulate intake. As a result, rats ingested substantially more of a mixture of 0.25% saccharin plus 6% glucose than they did of a comparable mixture of saccharin and fructose, even though rats ingest similar amounts of fructose and glucose without saccharin in single-bottle tests. Because the differential effect of saccharin on intake appeared within 2 h in naive rats, and did not greatly change over a 3-day period, it is probably not attributable to conditioning. These results suggest that these sugars have qualitatively different tastes.

Stimulus specificity in flavor acceptance learning

Infusing rats with 6% carbohydrate whenever they drank a test fluid stimulated their intake of 0.03-0.3% saccharin, 0.9% sodium chloride, and 0.5% oligosaccharide solutions within 1 to 3 days, but did not greatly increase intake of cherry-flavored water, 2% saccharin, 0.45% sodium chloride, monosodium glutamate, 0.025% sucrose octaacetate, or 0.4% maltodextrin, when food was available adlib. In general, it was more difficult to detect an effect with aversive stimuli, but it was possible to detect a significant effect with one such aversive flavor by either increasing the number of animals to permit detection of a small effect, or by using a preference test. For most stimuli, however, rats that had been trained with food available and then tested when food deprived showed significant increases in fluid intake, compared to rats that had been given the same flavor without carbohydrate infusions, even when plain water was infused in all rats during the food deprivation test. The following forms of evidence indicate that the increased intake is due to a form of Pavlovian conditioning. It tends to increase over repeated trials and to persist for a day after the carbohydrate infusions have been discontinued. Indeed, in one experiment, increased intake even persisted for a day when the infusion conditions were reversed, such that control rats were infused with carbohydrate and experimental rats were infused with water. Increased ingestion is attenuated by preexposure to the infusion in the absence of an appropriate taste solution. Increased ingestion is attenuated by preexposure to the taste solution in the absence of infusions (i.e., latent inhibition). Although increased intake is a form of associative conditioning, it is unlike malaise-conditioned taste aversions because taste aversions were conditioned to monosodium glutamate, cherry flavor, and saccharin with equal ease. The ease with which infusion increased intake is influenced by at least three different factors, degree of aversiveness, stimulus intensity, and rats' innate predisposition to acquire certain stimulus-response relationships more readily than others.

The 20 mm Medtronic Hall prosthesis in the small aortic root

BACKGROUND AND AIMS OF THE STUDY

The choice of prosthesis becomes crucial in the narrow aortic annulus. The 20 mm Medtronic Hall valve has a reduced sewing ring that fits in an annulus where only a 19 mm valve would fit. This study assesses the hemodynamic performance of this prosthesis at rest and at exercise, and compares it with two 19 mm mechanical prostheses.

MATERIALS AND METHODS

Forty-two patients were studied by Doppler echocardiography, a mean of 34 months following surgery. Twenty-six had a 19 mm prosthesis implanted (12 standard St. Jude Medical and 14 Monostrut valves) and 16 had a 20 mm Medtronic Hall. Parameters studied were peak velocity and transvalvular gradient, both at rest and at exercise, effective orifice area and valve index.

RESULTS

No differences were found between the two 19 mm valves, but when compared with the Medtronic Hall valve at rest, this valve showed significantly lower peak velocity and gradient (2.9 vs. 3.3 m/sec, p < 0.01, and 17 vs. 23 mmHg, p < 0.003, respectively) and higher effective orifice area and valve index (1.3 vs. 1.0 cm2, p < 0.01 and 0.81 vs. 0.62 cm2, p < 0.006, respectively). There were also significant differences under exercise.

CONCLUSIONS

The 20 mm Medtronic Hall prosthesis shows a significantly better hemodynamic performance, both at rest and under exercise, than other, 19 mm mechanical prostheses and represents a superior choice in valve replacement with a small aortic root.

Gastric emptying of ingested fat emulsion in rats: implications for studies of fat-induced satiety

Evidence that ingested fat acts in the intestine to produce satiety stems from studies showing that intraintestinal infusion of fat emulsion inhibits eating behavior of rats. In this study, we determined the appropriateness of infusion parameters used in these behavioral studies by measuring gastric emptying rates of both the aqueous and lipid components of Intralipid ingested normally by rats. Stomach contents were collected at different times 0-40 min after rats ingested Intralipid containing [14C]polyethylene glycol (PEG) and phenol red (PR) and were assayed for PEG, PR, and fat. The proportion of ingested fat remaining in the stomach was significantly greater than the proportion of ingested PEG or PR at all time points examined. Despite initial gastric emptying of fat during ingestion, consumption of Intralipid (0.5 or 1.1 kcal/ml) did not suppress subsequent solid food intake. The results indicate that 1) ingested fat emulsion rapidly partitions in the rat stomach into an aqueous phase, which empties rapidly, and a lipid phase, which empties slowly, and 2) normal ingestion of Intralipid is not immediately satiating. These observations raise questions about the physiological significance of the rapid and marked suppression of feeding behavior produced by intraintestinal infusion of Intralipid.

Stimulation of fluid intake by maltodextrins and starch

Maltodextrin solutions are more potent stimulators of fluid intake than are starch suspensions, even though these two substances are both glucose polymers. When rats were offered a choice of two fluids, one containing maltodextrin and the other containing the same concentration of starch, rats preferred maltodextrin; this preference increased over successive days for rats given 7.4% or 10% carbohydrate but not for rats given 1% carbohydrate. Rats offered fluids containing artificial flavors mixed with maltodextrin and starch acquired preferences for flavors paired with 10% or 7.4% maltodextrin but not for flavors paired with 1% maltodextrin. In an attempt to determine whether this greater preference for maltodextrin is due to an innate flavor preference, rats were given a choice of maltodextrin containing sucrose octaacetate vs. plain starch; these rats initially preferred starch but subsequently ingested more maltodextrin flavored with sucrose octaacetate than plain starch. Direct evidence for a postingestive factor was obtained by giving rats intragastric infusions of either maltodextrin, starch, or vehicle whenever they drank a dilute saccharin solution. Both carbohydrates stimulated fluid intake, but maltodextrin did so more rapidly (within 1 day rather than the 2 days of training required with starch infusions). These results indicate that some difference in the postingestive effects of maltodextrin and starch contributes to the greater intake-stimulating effect of maltodextrin. The postingestive factor responsible for the difference between maltodextrin and starch has not been identified, but it is not the amount of utilizable energy because rats prefer maltodextrin over starch even when the starch suspension contains more calories than does the maltodextrin solution. It is proposed that the postingestive factor differentiating these substances is rate of digestion.

Sucrose and fructose have qualitatively different flavors to rats

Previous studies suggest that rats might be able to discriminate between sucrose and fructose, but no previous study has examined this possibility in much detail. Rats were conditioned to avoid either sucrose or fructose by injecting them with lithium chloride when they drank these substances. Control rats were given the same injections but were not exposed to either sugar during training. After training, the rats were given a choice of fructose vs. sucrose. Data from control rats provided information about the relative taste intensity of the sugars. If the sugars possess only a single gustatory quality, control rats should prefer the sweeter sugar; under this assumption, sucrose appears to be two-four times sweeter than fructose. The two sugars share a common taste because rats trained to avoid sucrose avoided fructose when the fructose concentration was much greater than the sucrose concentration. Nevertheless, the two sugars are discriminable because, when the apparent sweetness of the sugars was matched, rats showed a greater aversion to the sugar they were trained to avoid. Aversions to sucrose and fructose also generalized to maltodextrins, but sucrose may have a somewhat greater maltodextrin flavor than does fructose. It is proposed that the biological function of maltodextrin taste is to allow animals to sense the ratio of glucose to fructose in foods.

Food intake in diabetic rats: relationship to metabolic effects of insulin treatment

Hyperphagic streptozotocin-diabetic rats were given week-long treatment with 0 (vehicle), 3, or 6 U/rat/day of regular insulin via a SC osmotic pump. Insulin reduced urinary glucose excretion and plasma glucose and increased body weight in a dose-related manner starting on the first day of treatment. Insulin treatment also increased carcass weight, carcass fat, and liver glycogen within 3 days. Food intake did not decrease until the fifth day of insulin treatment, and this change was unrelated to the amount of insulin administered. These results show that the effects of insulin on food intake and metabolism of diabetic rats can be dissociated with respect to both time course and dose of insulin. The findings indicate that hypoinsulinemia, glycosuria, body weight loss, and depletion of body fat and liver glycogen are symptoms of diabetes, not causes of diabetic hyperphagia.

Chemosensory similarities among oils: does viscosity play a role?

It is widely thought that viscosity plays an important role in the perception of fats. Rats were conditioned to avoid oil suspensions by treating them with lithium chloride after they had ingested the oil suspension. Control rats received the same lithium chloride injection after they drank vehicle. Three, chemically different, oils were examined, triglyceride oil, silicone oil and mineral oil. Rats trained to avoid a 4% aqueous suspension of one of these oils, reliably avoided suspensions containing any of the other oils, although the rats could discriminate between the oils. The viscosity of the oil suspension was slightly greater than the viscosity of the vehicle alone. However, rats trained to avoid an oil suspension, did not avoid a fluid having a viscosity similar to that of the oil suspension. In order to assess the possibility that rats could sense the viscosity of the oil separately from that of the vehicle, rats were tested for their aversion to oils having viscosities much higher and much lower than that of the oil they were trained to avoid. Rats trained to avoid triolein having a viscosity of 67 cp, reliably avoided silicone oils having viscosities of 5 and 203 cp. However, rats trained to avoid oil did not avoid an oil-free fluid having a viscosity of 22-29 cp. A final experiment examined whether the use of viscous or non-viscous vehicles influenced the conditioned aversion. No significant effect of vehicle viscosity appeared. Thus, chemically-diverse oils are perceived, by rats, to have some perceptible attribute in common. It is proposed that this common physical attribute is boundary lubrication rather than viscosity.

High-dose mercaptopurine followed by intermediate-dose cytarabine in relapsed acute leukemia

PURPOSE

This phase I/II study was designed to explore the feasibility, toxicity, and potential efficacy of administering high-dose continuous intravenous mercaptopurine (6MP) followed by intermediate-dose continuous intravenous cytarabine (Ara-C) to children with relapsed or unresponsive acute leukemia.

PATIENTS AND METHODS

Twenty-three children with relapsed or unresponsive acute leukemia (13 myeloid, 10 lymphoid) were entered onto the study. After initial hydration and alkalinization, 1,000 or 1,250 mg/m2 of 6MP was administered by continuous intravenous infusion over 24 hours. Following another period of hydration, 500 mg/m2 of Ara-C was administered by continuous intravenous infusion daily for 4 days. In 17 children, plasma concentrations of 6MP were measured at hours 4, 24, and 27 of the 6MP infusions. Plasma concentrations of Ara-C were measured at hours 8, 24, 48, 72, and 96 of the Ara-C infusions. Intracellular Ara-C triphosphate (Ara-CTP) concentrations were measured in peripheral-blood leukemia cells of the five patients with sufficient cells for measurement. Children who developed remission received repeated courses of this regimen every 3 to 4 weeks until relapse or completion of 12 courses.

RESULTS

Of 13 children with acute myeloid leukemia (AML), six developed complete remissions (CRs) lasting 7 months to nearly 4 years. Two children remain in CR with normal growth, development, and health 3 years after cessation of treatment. Of 10 children with acute lymphoid leukemia (ALL), one had a CR of 2 months' duration. Dose-limiting toxicity consisted of severe hematosuppression with fever, neutropenia, and serious infection. There were two toxic deaths. The mean steady-state plasma concentrations of 6MP were approximately 4 mumol/L and of Ara-C approximately 3 mumol/L. The median Ara-CTP concentration in peripheral-blood leukemia cells was 308 mumol/L at hour 8 of the Ara-C infusion.

CONCLUSION

High-dose continuous intravenous 6MP followed by intermediate-dose intravenous Ara-C produced CRs of longer than 6 months in approximately half of children with relapsed or unresponsive AML. Further study of this drug regimen is justified.

Stimulation of fluid intake by carbohydrates: interaction between taste and calories

Rats were trained in an apparatus that infused water or nutritive fluids into their stomachs every time that they drank flavored fluids. Rats given saccharin to drink by mouth drank more fluid than rats given cherry-flavored water to drink. Furthermore, rats given saccharin to drink ingested much more fluid if they were given intragastric infusions of 6% carbohydrate than intragastric infusions of plain water. This stimulatory effect of carbohydrate infusion occurred within 1 or 2 days of training and was very large, amounting to > or = 70% increase in fluid intake compared with rats drinking saccharin and infused with water. On the other hand, infusions of 6% carbohydrate had no effect on the intake of rats given cherry-flavored water to drink. In an attempt to determine whether rats could be trained to respond to cherry flavor at all, rats were infused with a liquid diet whenever they drank cherry or saccharin-flavored water. When dry food was withheld, the rats learned to increase fluid intake so as to feed themselves. The rats given saccharin to drink acquired this task more readily than rats given cherry flavor to drink, but both groups took in normal amounts of food by the end of the 10-day training period. It is concluded that it is much easier to condition an increase in fluid intake with intragastric infusions of carbohydrate than with an arbitrary nonsweet flavor.

Glucose polymer taste is not unitary for rats

The present studies examined rats' responses to two maltodextrin preparations. One maltodextrin, a maltooligosaccharide, had an average chain length of 4.4 glucose units. The other maltodextrin was a maltopolysaccharide, having an average chain length of 22. In 24-h preference tests, rats strongly preferred 1% and 5% maltodextrin over water, regardless of the type of maltodextrin offered. When given a choice of two maltodextrins, rats preferred the maltooligosaccharide, but the degree of preference was influenced by the rats' previous experience with maltodextrins. Conditioned flavor aversion experiments were conducted to determine whether rats detect qualitative flavor differences between the these two maltodextrins. Rats trained to avoid one maltodextrin also avoided the other maltodextrin. Nevertheless, rats could be trained to drink maltooligosaccharide but avoid maltopolysaccharide; these rats showed no reliable tendency to respond to the intensity of maltooligosaccharide flavor. Therefore, maltodextrins of varying chain length differ more in flavor quality than in flavor intensity. This difference in flavor quality is not attributable to known sweet and starch flavors because neither maltodextrin contained much glucose and because rats trained to avoid the polysaccharide did not avoid starch. Because rats can discriminate between solutions containing only 0.5-1% maltodextrin, their ability to discriminate among carbohydrates must be far more acute than that of humans.

Relative preference for starch and sugar in rats

When given a choice between fluids containing equal amounts of corn starch or glucose, Fischer rats preferred the fluid containing starch when the fluids contained 0.5%, 1%, 5%, or 20% carbohydrate, but not when the fluids contained 10% carbohydrate. Fischer rats preferred 0.5% sucrose over 0.5% starch on the first day of testing, but then switched to preferring starch. Rats of the CD strain also preferred 0.5% starch over 0.5% sucrose or 0.5% glucose, but showed no reliable preference when offered a choice of 5% starch vs. 5% sucrose or 5% glucose. Most experiments used corn starch, but rats prefer 1% rice, wheat, and tapioca starch over 1% glucose. Rats given only one substance to drink, drank more fluid if the fluid contained 1% starch than if it contained 1% glucose. Preexposing rats to either glucose or starch for 3 days did not influence subsequent preference for starch over glucose. Since the starch and glucose mixtures used in the present work had the same number of calories, preference for starch over glucose must be attributed to the hedonic effects of starch flavor rather than to the postingestive effects of starch.

Role of olfaction in starch and oil preference

Two different techniques were used to assess the role of olfaction in the preference rats show for dilute nutrient suspensions and solutions. Removal of the olfactory bulbs reduced but did not abolish preference for 1% starch and oil emulsions. Removal of the olfactory bulbs also reduced preference for sucrose, Polycose, and saccharin. In another experiment, rats were rendered anosmic with intranasal zinc sulfate. The degree of anosmia was evaluated by measuring preference for an aqueous solution of citral and vanillin. Rats whose avoidance of citral plus vanillin had been abolished by zinc sulfate continued to prefer a 1% starch suspension over vehicle, although starch preference was significantly reduced. It is concluded that starch and oil preference is mediated by both olfactory and nonolfactory cues.

Food deprivation reduces rats' oil preference

Rats normally prefer dilute oil suspensions over vehicle, but this preference can be abolished by exposing them to dilute oil suspensions during a period of food deprivation. In the first series of experiments, rats were given a choice of 0.5-0.9% triolein vs. vehicle for 4 consecutive days each week for 3 weeks. Food was available ad libitum on days 1, 2 and 4; no food was available on day 3. Preference for oil suspension dropped sharply after, but not during, each occasion that food was withheld. Similar experiments using starch, Polycose, or sucrose did not show comparable deprivation-induced changes in preference. The second series of experiments included separate control and experimental groups. The experimental group was food deprived for 1 day when test fluids were available. The control group was food deprived the day after the test fluids were available. Food was returned and the test fluids were removed for a few days. Fluid preference was then retested with food available ad libitum. After this cycle of two preference tests was repeated 1-2 times, the experimental group showed substantially lower oil preference than did the control group. Similar results were obtained with 0.5% triolein, 0.5% soybean oil, and 5% soybean oil. A similar experiment in which a vanillin-citral flavor was used instead of oil did not show such an effect. However, preference for the vanillin-citral flavor was decreased in rats exposed to a mixture of this flavor and oil while they were food deprived. It is proposed that rats readily learn to associate oil flavor, but not other flavors, with the aversive effects of food deprivation.