Variations in diet cause alterations in microbiota and metabolites that follow changes in disease severity in a multiple sclerosis model.

Multiple sclerosis (MS) is a metabolically demanding disease involving immune-mediated destruction of myelin in the central nervous system. We previously demonstrated a significant alteration in disease course in the experimental autoimmune encephalomyelitis (EAE) preclinical model of MS due to diet. Based on the established crosstalk between metabolism and gut microbiota, we took an unbiased sampling of microbiota, in the stool, and metabolites, in the serum and stool, from mice (Mus musculus) on the two different diets, the Teklad global soy protein-free extruded rodent diet (irradiated diet) and the Teklad sterilisable rodent diet (autoclaved diet). Within the microbiota, the genus Lactobacillus was found to be inversely correlated with EAE severity. Therapeutic treatment with Lactobacillus paracasei resulted in a significant reduction in the incidence of disease, clinical scores and the amount of weight loss in EAE mice. Within the metabolites, we identified shifts in glycolysis and the tricarboxylic acid cycle that may explain the differences in disease severity between the different diets in EAE. This work begins to elucidate the relationship between diet, microbiota and metabolism in the EAE preclinical model of MS and identifies targets for further study with the goal to more specifically probe the complex metabolic interaction at play in EAE that may have translational relevance to MS patients.

Identification of tobacco-specific carcinogen in the cervical mucus of smokers and nonsmokers.

BACKGROUND: In 1996, an estimated 15,700 new cases of cancer of the uterine cervix and 4,900 deaths from this disease were expected to occur in the United States. In a recent international study, human papillomavirus DNA was found in more than 90% of cervical tumor specimens examined, irrespective of the nationality of the patients from whom the samples were obtained. Although infection with human papillomavirus is the major known risk factor for the development of cervical cancer, it alone is not sufficient. Other etiologic factors that have been associated with this disease include deficiencies in micronutrients, lower socioeconomic status, oral contraceptive use, and cigarette smoking. Several compounds from cigarette smoke (nicotine and its major metabolite, cotinine) have been identified in cervical mucus, and the occurrence of smoking-related DNA damage in the cervical epithelium has been documented. PURPOSE: This investigation was conducted to determine for the first time whether carcinogenic tobacco-specific N-nitrosamines are present in the cervical mucus of cigarette smokers and of nonsmokers (most likely as a result of environmental exposure). METHODS: Cervical mucus specimens from 15 smokers and 10 nonsmokers were subjected to supercritical fluid extraction with the use of carbon dioxide that contained 10% methanol, and the resultant extracts were analyzed for tobacco-specific nitrosamines by use of a very sensitive method that involved gas chromatography and mass spectroscopy analyses. RESULTS: In a total of 16 samples obtained from 15 women who were current smokers (two samples from the same woman), we detected the tobacco-specific nitrosamine 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) at concentrations that ranged from 11.9 to 115.0 ng/g of mucus. Only one of a total of 10 cervical mucus specimens obtained from 10 women who claimed to be nonsmokers did not contain detectable NNK, and NNK concentrations ranged from 4.1 to 30.8 ng/g of mucus in the specimens from the remaining nine women. The concentrations of NNK in specimens from cigarette smokers were significantly higher than those from nonsmokers (mean +/- standard deviation: 46.9 +/- 32.5 ng/g of mucus versus 13.0 +/- 9.3 ng/g of mucus; two-tailed Student's t test, P = .004). CONCLUSION: The cervical mucus of cigarette smokers contains measurable amounts of the potent carcinogen NNK. This compound represents the first tobacco-specific carcinogen identified in this physiologic fluid of women who smoke cigarettes. The presence of NNK in the cervical mucus of nonsmokers is likely due to environmental exposure or to the fact that some of the subjects in this study may not have revealed that they occasionally smoked cigarettes. IMPLICATIONS: The presence of NNK in human cervical mucus further strengthens the association between cervical cancer and tobacco smoking.

The Enigma of Rapid Repeat Pregnancy: A Qualitative Study of Teen Mothers.

STUDY OBJECTIVE: Rapid repeat pregnancy accounts for 18% of teen pregnancies and leads to adverse health, economic, and developmental outcomes for teen mothers and their children. Few interventions have been successful in reducing rapid repeat pregnancy. In this qualitative study we examined adolescent mothers' perceptions of their decision-making and behaviors that helped prevent or promote a rapid repeat pregnancy. DESIGN, SETTING, PARTICIPANTS, INTERVENTIONS, AND MAIN OUTCOME MEASURES: Semistructured interviews were conducted with 31 adolescent mothers, aged 16-21 years; 15 of these subjects experienced a repeat pregnancy within a year of their first child's birth and 16 had not. Two researchers used a grounded, inductive technique to identify emergent themes; interviews were subsequently coded accordingly. Counts were tabulated of the number of times themes were endorsed among those with or without a repeat pregnancy. RESULTS: Four overarching themes emerged from the interviews: intentionality regarding pregnancy planning, patients' degree of independence in making contraceptive choices, sense of control over life experience, and barriers to follow-through on contraceptive planning. Teens who had not experienced a rapid repeat pregnancy more often endorsed themes of intentionality in preventing or promoting a pregnancy, independence in decision-making, and feelings of control over their experience. Ambivalence and lack of decision-making about seeking another pregnancy were frequently endorsed by mothers who had experienced a second pregnancy. CONCLUSION: Decision-making regarding seeking or preventing a rapid repeat pregnancy is complex for teen mothers; techniques to help support decision-making or to delay pregnancy until decision-repeat making is complete might be important in reducing rapid pregnancy.

Pulmonary intravascular lymphomatosis: presentation with dyspnea and air trapping.

Intravascular lymphomatosis (IVL) is a rare lymphoid neoplasm that is typically of B-cell lineage and characterized by proliferation of malignant cells within small arterioles, capillaries, and venules. We report a patient with pulmonary IVL who presented clinically with progressive dyspnea, fever, and a dry cough. Pulmonary function tests revealed a marked decrease in diffusion capacity with airflow obstruction and severe air trapping. High-resolution CT (HRCT) of the chest with inspiratory and expiratory images revealed mosaic attenuation consistent with air trapping. Transbronchial biopsies revealed the diagnosis of IVL with capillary expansion in the alveolar and peribronchiolar interstitial tissue. IVL should be considered in the differential diagnosis of a patient with an interstitial lung disease, air trapping on pulmonary function tests, and mosaic attenuation on HRCT. Transbronchial biopsies may be the initial diagnostic procedure of choice.

Sham feeding in rats after ventromedial hypothalamic lesions and vagotomy.

Sham feeding was examined in female rats with ventromedial hypothalamic (VMH) lesions with or without abdominal vagotomy. In Experiment 1, intact rats consumed more than twice as much sweet milk during 1-hr tests of sham feeding (M = 13.0 ml) as they did when feeding normally (M = 5.5 ml). Rats with VMH lesions showed exaggerated sham feeding, which was elevated almost fourfold (M = 56.6 ml) over their already high normal feeding baseline (M = 15.1 ml). In Experiment 2, vagotomy substantially reduced sham feeding in rats with VMH lesions. After vagotomy, VMH rats sham fed half as much (M = 23.7 ml) as nonvagotomized VMH rats did (M = 46.8 ml). Vagotomy did not, however, reduce sham feeding to control levels (M = 13.1 ml). These results are consistent with the hypothesis that VMH hyperphagia arises from exaggeration of orosensory responsiveness, which is, in part, a consequence of perturbed vagal function.

Fathers of children born to adolescent mothers. Predictors of contact with their children at 2 years.

OBJECTIVE: To examine factors associated with long-term involvement of the fathers of children born to adolescent mothers receiving health care in a teen-tot clinic. DESIGN: Ninety-three first-time adolescent mothers younger than 18 years receiving care in a hospital-based teen-tot clinic participated in standardized structured interviews at 2 weeks and 24 months post partum. Data were obtained on demographic factors, the father's prenatal and delivery involvement, frequency of the father's contact with his child, and his participation in child care and financial support of the child. RESULTS: Factors associated with at least monthly contact between father and child during the first 24 months of the child's life were attending at least one prenatal visit, seeing the newborn in the hospital, and a reported supportive relationship between the young mother's family and the father at the 2-week interview. Age of the father and his education, work, or living arrangement did not predict involvement at 24 months. CONCLUSIONS: Our study suggests an association between a father's active participation in both the prenatal and neonatal periods and later contacts between children of adolescent mothers and their fathers. Since other studies indicate that paternal involvement results in more effective maternal parenting and satisfaction, interventions that encourage fathers' participation in both prenatal and intrapartum care should be developed and rigorously evaluated.

Celiac vagotomy reduces suppression of feeding by jejunal fatty acid infusions.

We investigated the role of the celiac branch of the vagus nerve in suppression of food intake produced by jejunal fatty acids infusions. Following selective celiac vagotomy or sham surgery, adult, male Sprague-Dawley rats received 7 h infusions of linoleic acid or saline through indwelling jejunal catheters on four consecutive days. Although linoleic acid still produced significant suppression of intake in rats with celiac vagotomy, it was less effective in these animals than in controls. The temporal pattern of results suggested that celiac afferent fibers are involved in mediating both pre- and postabsorptive effects of infused fatty acids.

Jejunal or portal vein infusions of lipids increase hepatic vagal afferent activity.

Jejunal infusions of linoleic acid, corn oil, or caprylic acid significantly increased hepatic vagal afferent activity, whereas saline infusions were ineffective. The magnitude of response was greatest with either linoleic acid or corn oil. Hepatic portal infusions of linoleic acid, Liposyn II, or caprylic acid significantly increased hepatic vagal afferent activity, whereas 5% albumin/phosphate buffer vehicle was ineffective. The magnitude of response was greatest with either linoleic acid or Liposyn II. These data show that either jejunal or portal infusions of lipids increase activity of hepatic vagal afferents and could potentially serve as a complementary and/or alternative substrate to celiac vagal afferents in mediating the effects of jejunal infusions of lipids in suppressing food intake.

Inhibitory effects of cholecystokinin develop through interaction with duodenal signals.

I previously reported that cholecystokinin octapeptide (CCK-8) had little effect on feeding motivation as indexed by runway performance, but that substantial impairment resulted from the interaction of CCK-8 and prefeeding of sucrose. If the sucrose was sham-fed, potentiation of the effect of CCK-8 was seen only after large doses. The current experiments examined whether synergy between 1 microgram/kg CCK-8 and prefeeding could be reproduced using gastric, duodenal, or hepatic-portal infusions. Gastric and duodenal infusions of 30% sucrose were effective; in conjunction with CCK-8 they decreased running speed as substantially as prefeeding did. The duodenal effect was specific. Glucose appeared to be as effective as sucrose, whereas equi-osmotic saline and mannitol were not. Intraportal glucose was relatively ineffective; interaction with CCK-8 was seen only after very large infusions, and the resulting running speeds did not approach those seen after prefeeding or gastrointestinal infusions. These results suggest that decreased feeding motivation after 1 microgram/kg CCK-8 develops through synergy between this peptide and a carbohydrate-sensitive signal generated within the small intestine.

Cholecystokinin interacts with prefeeding to impair runway performance.

Previous experiments demonstrated the ineffectiveness of the C-terminal octapeptide of cholecystokinin (CCK-8) for impairing runway performance by food-deprived rats. These results were consistent with the proposal that CCK-8 does not reduce food intake by inhibiting appetitive motivation but instead acts late in the meal to prematurely trigger satiety. For further evaluation of this hypothesis, the effect of CCK-8 on runway performance was assessed after 21 h food-deprived rats consumed a partial meal of 30% sucrose. Injection of 1.0 micrograms/kg CCK-8 after rats were allowed 3 min (6.2 ml consumed) or 5 min (9.7 ml) access to 30% sucrose produced significant reductions in running speed of 43% and 70%, respectively. After 5 min prefeeding, 0.25 and 0.50 micrograms/kg CCK-8 also produced significant decreases in speed of 20% and 59%, respectively. By contrast, CCK-8 had little or no effect without prefeeding. Doses of 0.25 and 0.50 micrograms/kg failed to affect running speed on these tests and 1.0 micrograms/kg produced a small (7%) though significant decrease. These results suggest that inhibition of feeding motivation after CCK-8 administration develops during the course of the meal through interaction with signals generated by the ingestion of food.

Dose-dependent interaction between cholecystokinin and sham feeding.

Previous work in this laboratory indicated that decreases in feeding motivation produced by cholecystokinin octapeptide (CCK-8) develop through synergism with signals generated by feeding. In these experiments, we used a runway paradigm to assess the contribution of signals from the oral cavity to this interaction. In contrast to the substantial (44%) impairment in runway performance produced by the combination of 1 microgram/kg CCK-8 and 5 min normal prefeeding, 5 min sham feeding failed to potentiate the effect of 1 microgram/kg CCK-8. Sham feeding in conjunction with this dose of CCK-8 reduced running speed by no more (2%) than CCK-8 alone (9%). Similar results were obtained whether rats were allowed a longer sham feeding interval (12 min) or the prefeeding interval was shifted in time so that it ended only 3 min before the start of the runway test. By contrast, larger doses of CCK-8 interacted with 5 min sham feeding to substantially impair runway performance; significant decreases in speed of 29% and 41% were observed after 2 and 4 micrograms/kg CCK-8, respectively. Results with these doses indicate that synergy between CCK-8 and signals from the oral cavity can contribute to the inhibitory effects of this agent. However, the failure of the combination of the 1 microgram/kg dose and sham feeding to replicate the interaction seen with normal prefeeding indicates the additional involvement of signals arising from food stimulation distal to the oropharynx.

Ventromedial hypothalamic and paraventricular nucleus lesions damage a common system to produce hyperphagia.

We investigated the anatomical basis of paraventricular (PVN) and ventromedial (VMH) hypothalamic hyperphagia. Asymmetrical electrolytic lesions, damaging the VMH and PVN contralaterally, produced significant hyperphagia and weight gains (mean = 257.2 g) almost three times those of controls (89.8 g) during 56 postsurgical days. Weight gain in these rats was not significantly different from that in rats with bilateral lesions of the VMH (277.2 g) or PVN (188.2 g). Combined bilateral destruction of the PVN and VMH produced weight gain (272.8 g) almost identical to that seen after bilateral VMH lesions alone. The lack of additivity of these combined lesions and the effectiveness of the asymmetrical lesions are consistent with the hypothesis that lesions of either of these two regions damage a longitudinally running system to produce elevated food intake and body weight. Cell bodies of this system may lie within the PVN and send efferent projections through the VMH. Hyperinsulinemia developed only in rats with bilateral damage in the VMH. Thus, hypothalamic hyperphagia and hyperinsulinemia appear to be dissociable, reflecting damage to separate neural systems.

Ineffectiveness of cholecystokinin in impairing runway performance.

We compared changes in runway performance by rats for sucrose reward following injections of the synthetic C-terminal octapeptide of cholecystokinin (CCK-8) with those seen after variations in food deprivation and injections of lithium chloride. No effects on running for either 10% or 30% sucrose were found following 0.5 to 4.0 micrograms/kg of CCK-8, though such doses suppressed 30-min sucrose intake up to 53%. Statistically reliable slowing of running for 10% sucrose was observed on two series of tests after 8.0 micrograms/kg of CCK-8. Running for 30% sucrose was not significantly affected by this dose. The general ineffectiveness of CCK-8 for producing decrements in running spread contrasts with significantly reduced performance after either reductions in food deprivation (21 h vs 12 and 3 h) or injections of 75 mg/kg lithium chloride. These results suggest that the mode of action of CCK-8 in reducing food intake is different than that produced by changes in hunger or by non-specific interference with motivation by malaise. The finding that CCK-8 can substantially reduce consumption with no apparent changes in appetitive motivation is consistent with the hypothesis that this substance acts only late in the meal to prematurely trigger satiety.

CCK-8 activates hepatic vagal C-fiber afferents.

Intravenous administration of 2 micrograms/kg CCK-8 increased the single unit activity of 54% of hepatic vagal afferent fibers. Conduction velocity tests indicated that all of these units were C fibers. The increase in hepatic vagal activity produced by CCK-8 was significantly reduced by i.v. administration of 200 micrograms/kg of the CCKA receptor antagonist devazepide. Control comparisons indicated that this reduction was not an artifact of tachyphylaxis resulting from repeated administration of CCK-8. Further, the inability of pretreatment with atropine and hexamethonium to reduce the increases in hepatic vagal activity produced by CCK-8 suggests that the latter effect was not secondary to changes in gastrointestinal motor function. These outcomes demonstrate that activation of CCKA receptors by CCK-8 increases hepatic vagal afferent activity and support the view that the duodenal satiety action of CCK is mediated by the hepatic branch.

Seizure-induced transient hippocampal abnormalities on MR: correlation with positron emission tomography and electroencephalography.

We report transient focal abnormalities on MR in a patient having frequent electrographic seizures that were not obvious clinically. Marked mass effect (confirmed with volumetric studies) and abnormal T2 signal intensity in the right hippocampal region correlated with electroencephalographic ictal activity and with increased positron-emitting radiotracer uptake in the medial temporal lobe. The follow-up MR 2 months later, after electroencephalography findings normalized, revealed no hippocampal abnormalities.

Effect of pyloric cuffs on cholecystokinin satiety.

Because inflation of a pyloric cuff during feeding blocks gastric emptying and increases gastric distention, this device was used to test the hypothesis of synergism between gastric distention and cholecystokinin octapeptide (CCK-8) in reducing intake. Adult, male Sprague-Dawley rat were allowed 20-min access to 30% sucrose, with or without inflation of pyloric cuffs, after intraperitoneal injection of saline or 1, 2, or 4 micrograms/kg CCK-8. Cuff inflation resulted in large increases in gastric volume at the end of feeding tests. However, this manipulation failed to enhance the effectiveness of any dose of CCK-8. In fact, data analyses revealed trends suggestive of decreased effectiveness of the two lowest doses under these conditions. The effect of 4 micrograms/kg CCK-8 was almost identical in tests with and without cuff inflation. These results are contrary to the prediction of greater potency of CCK-8 resulting from increased gastric distention.

Precise estimation of carcass fat from total body water in rats and mice.

We investigated the utility of carcass water for predicting adiposity in a sample of 373 rats and mice from nine studies involving several models of obesity and experimental manipulations. A single regression equation was derived for estimating percentage carcass fat--%FAT predicted = -1.272 X %WATER + 95.96 (r = -.988). The function is linear across the range of %FAT observed (6.6% to 68.8%) and fits very well the data of each of the nine experiments. Comparisons between this function and the Lee Index as measures of obesity indicate, by contrast, the considerable imprecision of the latter method. Because studies in our analysis employed formalin fixation, we also provide an equation for use with unfixed tissue. This corrected function accounts for 97.8% of the variance in independent data from 19 published reports. We suggest that both of the functions presented here have general applicability for precise determination of body composition of rats and mice and, further, that the body water analysis offers significant advantages in terms of reduced time and expense.

The thermodilution technique for measuring resting energy expenditure does not agree with indirect calorimetry for the critically ill patient.

BACKGROUND: The complications associated with overfeeding critically ill patients are well documented. Indirect calorimetry is touted as the gold standard for measuring resting energy expenditure (REE). Unfortunately, the device is expensive, and many centers do not have this technology. The thermodilution technique for measuring cardiac output and calculating REE using the Fick equation has been reported to be an acceptable alternative. This study compared these techniques in a critically ill population. METHODS: Forty consecutive patients with indwelling Swan-Ganz catheters in the surgical intensive care unit were prospectively studied while under the consultative care of the nutrition support service. REE was determined in all patients by both techniques within a 2-hour period. An error of 5% (approximately+/-100 kcal/d) between the two methods was deemed acceptable for clinical use. RESULTS: Mean values for REE were 1928+/-558 vs 1898+/-518 kcal/d for the indirect calorimetry and thermodilution methods, respectively, and were not significantly different. However, there was great variation between the two techniques for the majority of patients such that REE determinations did not agree (t = 6.8; p < .0005). In 70% of the patients, REE determinations differed by > or =20% and in 10% of the patients by 50%. Additionally, the greater the difference between the two methods, the more the thermodilution method tended to overestimate REE. CONCLUSIONS: When compared with indirect calorimetry in a critically ill population, the thermodilution method demonstrated an intersubject variability that is unacceptable for clinical use.

Shielding of longitudinal magnetic fields with thin, closely spaced, concentric cylinders of high permeability material.

Formulae for the longitudinal shielding effectiveness of N thin, closely spaced, concentric cylinders of high permeability material have been developed and experimentally tested. For shields which cannot be oriented, or which change their orientation in the ambient field, the shielding effectiveness for longitudinal fields is generally the limiting criterion and no design formulae have previously been published for more than two shields. A simple diagrammatical method of writing the shielding formula is presented. Use of these equations is demonstrated by application to the design of magnetic shields for hydrogen maser atomic clocks. Examples of design tradeoffs such as size, weight, and material thickness are discussed. Experimental data on three sets of shields fabricated by three manufacturers are presented.

Studies of pituitary-adrenal-testis interaction in sheep. II. The effects of repeated injections of adrenocorticotrophic hormone outside the breeding season.

The administration of 0.5 mg of long-acting adrenocorticotrophic hormone (ACTH, Synacthen-Depot) twice daily for 5.5 d to four rams outside the breeding season caused marked rises in plasma cortisol without any evidence of adrenal depletion. This treatment also caused marked rises in basal plasma follicle stimulating hormone (FSH) concentrations which remained high even after cessation of treatment. Plasma FSH responses to 5 ug of gonadotrophin releasing hormone (GnRH) were consistently observed and ACTH treatment increased the FSH response to GnRH. In contrast, spontaneous fluctuations in the plasma luteinizing hormone (LH) and testosterone concentrations were abolished by ACTH treatment. The quantity of testosterone released after GnRH (estimated by the maximum values reached and by the area under the response curve) was also suppressed while that of LH was only slightly lower. A comparison of the results of this experiment with those obtained in rams during the breeding season showed that the effects of ACTH on LH and testosterone were more marked during the breeding season. In contrast, the effect of ACTH on FSH is to increase the latter during the nonbreeding season, whereas no effect was observed during the breeding season.