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Biomedical subjects

M H Fernstrom

Publications and source records attributed to M H Fernstrom.

At least 37 records · Page 2Linked to original sources
PubMed1991

Weight change in depression: influence of "disinhibition" is mediated by body mass and other variables.

The direction of weight change (gain or loss) in depression has recently been found to be a stable characteristic of patients across depressive episodes. A search for determinants of the direction of weight change revealed two candidates: the body mass index (BMI) (weight in kilograms/height in meters squared) and a psychological variable, "disinhibition" of dietary restraint. The present study, of 68 patients with a history of recurrent depression, found a significant correlation between BMI and weight change; in other words, heavier persons were more likely to gain weight if depressed. There was also a correlation between "disinhibition" and weight change. "Disinhibition" correlated with BMI and, when controlled for BMI, age and sex, the correlation between "disinhibition" and weight change fell to insignificance. We conclude that BMI along with age and sex mediated the correlation between "disinhibition" and weight change.

Appetite↗
PubMed1991

In vivo tyrosine hydroxylation in rat retina: effect of aspartame ingestion in rats pretreated with p-chlorophenylalanine.

Rats were pretreated with p-chlorophenylalanine (PCPA) to inhibit hepatic phenylalanine hydroxylase. Two days later, oral aspartame (APM; aspartylphenylalanine methylester) administration substantially increased serum phenylalanine (Phe) concentrations and the ratio, in serum, of Phe to the sum of its competitors for transport into brain and retina (the other large neutral amino acids). Smaller changes occurred in serum tyrosine (Tyr) concentrations and in the ratio, in serum, of Tyr to the sum of its competitors. P-chlorophenylalanine-pretreated rats showed normal increases in retinal Tyr hydroxylation rate after Tyr injection, indicating that the enzyme was functionally normal. APM (0, 500, 1000, 1500 mg/kg body wt) intubation of PCPA-pretreated rats produced a dose-related increment in retinal Phe concentrations (up to six times normal values), no changes in retinal Tyr concentration, and no changes in retinal Tyr hydroxylation rate. The results thus indicate that very large increments in retinal Phe concentrations produced by enormous doses of APM do not modify Tyr hydroxylation in vivo.

Animals↗
PubMed1991

Abnormal caloric requirements for weight maintenance in patients with anorexia and bulimia nervosa.

OBJECTIVE: This study tested previous findings that patients with eating disorders who attain normal weight have abnormal caloric requirements for maintaining weight. METHOD: Fifty-three female patients meeting the DSM-III-R criteria for anorexia nervosa and/or bulimia nervosa were divided into four subgroups, and their daily caloric intake was measured over a weight-stable period. Patients with anorexia nervosa (restricting and bulimic subtypes) were studied 4 weeks after refeeding and weight gain, when they had attained 95% of average body weight. Patients with normal-weight bulimia (previously anorexic or never previously anorexic) were studied 1-4 weeks after admission to an inpatient unit. RESULTS: After weight restoration, restricting anorexic patients required significantly more calories per day to maintain weight than did bulimic anorexic patients, as measured with corrections for weight, body surface area, and fat-free mass. Previously anorexic normal-weight bulimic patients required significantly more calories per day to maintain weight than never-anorexic normal-weight bulimic patients, as measured with correction for weight but not with the other factors used to correct caloric intake. CONCLUSIONS: To maintain stable weight after weight restoration, restricting anorexic patients require a significantly higher caloric intake than do bulimic anorexic patients. Differences in caloric needs between normal-weight bulimic patients with and without histories of anorexia may depend on the methods used to correct caloric requirements. Body surface area may be the most precise correction factor across different subgroups of eating disorder patients. Elevated caloric requirements, when coupled with reduced food intake, may particularly contribute to relapse in anorexic patients.

Adolescent↗
PubMed1990

Direction of weight change in recurrent depression. Consistency across episodes.

The direction and extent of weight change during two separate episodes of severe, unipolar depression were assessed in 53 (unmedicated) outpatients in the Pittsburgh (Pa) study of maintenance therapy of depression. There was a high concordance (45 of 53 patients) of direction of self-reported weight change during the two episodes. Twenty-three patients lost weight during both episodes, 17 gained weight, and 5 showed no change. The extent of weight change between the two episodes was highly correlated. Self-reported weight change corresponded closely to measured weight changes in a large sample of the study population. Changes in appetite paralleled those in body weight. Duration of the episode and body mass index were related to the weight change, but two features of depression with which weight loss in depression has been associated (the endogenous character of the depression and it severity) were not. Direction and extent of weight change in unipolar depression appear to be stable patient characteristics across episodes and are thus potential markers for subtypes of depression. This stability of weight change is in sharp contrast to the lack of stability of the endogenous subtype in consecutive episodes of major depression.

Adult↗
PubMed1990

Effect of 8-hydroxy-2-(di-n-propylamino)-tetralin on the tryptophan-induced increase in 5-hydroxytryptophan accumulation in rat brain.

The injection of 8-hydroxy-2-(di-n-propylamino)-tetralin [8-OH-DPAT]reduced 5-hydroxytryptophan accumulation in vivo in rat cerebral cortex, hypothalamus and brainstem. Brain tryptophan levels were unaffected. Dose-related increases in 5-hydroxytryptophan accumulation produced by single injections of L-tryptophan (0, 25, 75 mg/kg ip) were substantially diminished by pretreatment with 8-OH-DPAT. The drug did not affect the tryptophan-induced increments in brain tryptophan level. Since 8-OH-DPAT is known to reduce the activity of serotonin neurons in vivo, these results suggest that when serotonin neurons are relatively inactive, the ability of an injection of tryptophan to stimulate serotonin synthesis is greatly attenuated.

5-Hydroxytryptophan↗
PubMed1990

Perception and hedonics of sweet and fat taste in smokers and nonsmokers following nicotine intake.

Nicotine's effects on reducing perception and/or hedonics of sweet and fat taste may lead to less intake of sweet tasting, high-fat foods by smokers, helping to explain their generally lower body weights. Smokers and nonsmokers (n = 10 males each) rated perception (intensity and sensitivity) and hedonics (liking) of sweet/fat taste in milk samples varying both in sucrose (0, 5, 10, 20% w/w) and fat (0.1, 3.5, 11.7, 37.6% w/w) concentration on two occasions, once following intermittent presentation of nicotine (15 micrograms/kg) via measured dose nasal spray and the other following placebo. Nicotine significantly reduced perceived intensity of fat but not sweet taste and had no effect on sensitivity to either taste. There was no effect of nicotine on hedonics of sweet/fat taste. On the other hand, although there were no differences between smokers and nonsmokers in perception of sweet or fat, hedonics of sweet/fat taste was reduced in smokers regardless of nicotine or placebo intake. Thus, nicotine may acutely decrease fat taste perception without influencing sweet/fat hedonics, while long-term exposure (i.e., being a smoker) may produce chronically decreased taste hedonics without altering perception.

Adolescent↗
PubMed1990

Metabolic effects of nicotine after consumption of a meal in smokers and nonsmokers.

The thermogenic effect of nicotine intake after calorie consumption was investigated to determine if nicotine influences metabolic response to a calorie challenge. Smokers and nonsmokers (10 males in each group), matched for body weight, age, and physical fitness, each participated in four sessions that involved consuming a liquid calorie load (4.77 kcal/kg body wt) or water, followed by nicotine (15 micrograms/kg body wt) or placebo via nasal spray every 20 min for 2 h. Energy expenditure was significantly increased above baseline resting metabolic rate (RMR) over the 2 h by nicotine alone (6.5% of RMR, p less than 0.01). However, the combined effect of nicotine after calorie load (20.1% of RMR, p less than 0.001) was not significantly greater than the effect of calorie load alone (18.4% of RMR, p less than 0.001). Smokers and nonsmokers did not differ in baseline RMR or in response to nicotine or calorie load. These results confirm the thermogenic effect of nicotine but suggest that the effect of nicotine after calorie consumption is less than additive.

Administration, Intranasal↗
PubMed1990

In vivo somatostatin, vasopressin, and oxytocin synthesis in diabetic rat hypothalamus.

The in vivo labeling of somatostatin-14, somatostatin-28, arginine vasopressin, and oxytocin was studied in rat hypothalamus after third ventricular administration of [35S]cysteine to streptozotocin-diabetic and normal rats. Immunoreactive somatostatin levels in hypothalamus were unaffected by diabetes, as was the incorporation of [35S]cysteine into hypothalamic somatostatin-14 and somatostatin-28. In contrast, immunoreactive vasopressin levels in hypothalamus and posterior pituitary (and oxytocin levels in posterior pituitary) were below normal in diabetic rats. Moreover, [35S]cysteine incorporation into hypothalamic vasopressin and oxytocin (probably mainly in the paraventricular nucleus because of its proximity to the third ventricular site of label injection) was significantly above normal. The increments in vasopressin and oxytocin labeling were reversed by insulin administration. In vivo cysteine specific activity and the labeling of acid-precipitable protein did not differ between normal and diabetic animals; effects of diabetes on vasopressin and oxytocin labeling were therefore not caused by simple differences in cysteine specific activity. These results suggest that diabetes 1) does not influence the production of somatostatin peptides in hypothalamus but 2) stimulates the synthesis of vasopressin and oxytocin. For vasopressin at least, the increase in synthesis may be a compensatory response to the known increase in its secretion that occurs in uncontrolled diabetes.

Animals↗
PubMed1989

In vivo tyrosine hydroxylation rate in retina: effects of phenylalanine and tyrosine administration in rats pretreated with p-chlorophenylalanine.

p-Chlorophenylalanine was administered to rats to inhibit hepatic phenylalanine hydroxylase activity. Two days later, phenylalanine injection was noted to produce substantial increases in serum phenylalanine levels, and relatively modest increments in serum tyrosine levels. Rats injected with p-chlorophenylalanine 2 days earlier showed a normal light-induced activation of retinal tyrosine hydroxylase activity in vivo, measured as dihydroxyphenylalanine accumulation following pharmacologic inhibition in vivo of aromatic L-amino acid decarboxylase activity. In addition, tyrosine injection into p-chlorophenylalanine-treated rats in the light produced anticipated increments in retinal tyrosine hydroxylation rate, showing the enzyme to be functionally normal. The acute administration of phenylalanine (62.5-500 mg/kg i.p.) to p-chlorophenylalanine-treated rats produced dose-related increments in retinal phenylalanine. In vivo tyrosine hydroxylation rate in retina was normal at all doses below 300 mg/kg. However, at the highest dose (500 mg/kg), when retinal phenylalanine levels were almost 5-times normal tyrosine hydroxylation rate consistently fell (to about half-normal values). These results demonstrate that very large elevations in tissue phenylalanine levels do not stimulate tyrosine hydroxylation in vivo, and that at extremely high levels phenylalanine inhibits tyrosine hydroxylation rate.

Animals↗
PubMed1989

Perception of appetite and weight change during treatment for depression.

As part of the Pittsburgh Appetite Test, 50 depressed outpatients reported their perceptions of appetite and weight change prior to and during chronic treatment with imipramine and psychotherapy. At the end of 4 months, as a group, patients were significantly more conscious of what they were eating, and reported a significant change in the frequency of regular meal consumption. No group changes were noted in frequency of snacking or late night eating, although weight change during treatment and obesity status modified these responses. Clinical response was unrelated to eating behavior. Perception of weight change varied with treatment: a 5 pound weight gain became highly problematic during recovery compared to the depressive episode. The interaction of these factors and antidepressant-induced weight gain are discussed.

Adult↗
PubMed1989

Resting metabolic rate in lean and obese children: relationship to child and parent weight and percent-overweight change.

Two studies were conducted to assess differences in metabolic rate as a function of child weight (study I); and the interaction of child and parent weight (study II). In both studies obese children had higher resting metabolic rates (RMRs) than lean children (p less than 0.05). Child weight accounted for 72 and 78% of the variance in RMR in studies 1 and 2, respectively. Including parental weight did not improve the prediction of RMR. After 6 mo of treatment, obese children decreased percent overweight, whereas lean children showed no change (p less than 0.01). RMR in both groups remained unchanged after 6 mo. These results indicate that the RMR is higher in obese than in lean children, that changes in percent overweight that result from increases in height and no change in weight do not decrease RMR over 6 mo, and parent weight does not improve the prediction of child RMR.

Basal Metabolism↗
PubMed1989

Depression, antidepressants, and body weight change.

The excessive weight gain observed during treatment of depression with antidepressant medications is caused in part, at least in some persons, by reductions in resting metabolic rate. Such problematic weight gain appears unrelated to clinical recovery, weight change during the depressive episode, prior weight, or other related factors. Preliminary results suggest that increased energy efficiency (of about 16-24%) during treatment with tricyclic antidepressants could promote weight gain even in the absence of a change in caloric intake. This is not a property of all antidepressants, as demonstrated by the increase in metabolic rate and associated weight loss observed during treatment with the monocyclic antidepressant compound fluvoxamine. Should these serotonergic compounds continue to be effective antidepressants, they may be better accepted by patients, and their use help avoid medication noncompliance. In considering energy balance and weight change, our focus has been drawn to altered metabolic rate. Continuing studies do not suggest an effect of antidepressants on appetite, particularly the presence of "carbohydrate craving," either during treatment or during a depressive episode. Certainly, a notable preference for highly palatable foods (rich in fats and carbohydrates) occurs during the depressive episode, but not during treatment. These foods cannot be labeled carbohydrates.

Antidepressive Agents↗
PubMed1988

Antidepressant-induced weight gain: a comparison study of four medications.

Body weight change was monitored in 73 hospitalized depressed patients treated with one of four antidepressants for 1 month. After a 2-week medication-free period, patients were randomly assigned to treatment with amitriptyline, nortriptyline, desipramine, or zimelidine. By the end of 1 month, treatment with all three tricyclic compounds promoted weight gain, with the greatest increase observed during amitriptyline treatment; less weight was gained by patients treated with nortriptyline and desipramine. In contrast, most patients treated with zimelidine showed no weight gain and, in many cases, demonstrated weight loss. Weight change during treatment was not associated with age, sex, severity of depression, obesity, weight loss during depression, or clinical response.

Adult↗
PubMed1988

Imipramine treatment and preference for sweets.

Antidepressant-induced changes in food preference were investigated in a group of 40 depressed patients before and during treatment with imipramine. As part of a validated survey, the Pittsburgh Appetite Test, self-reported food preference was categorized by both nutrient and hedonic properties to define individual response. After 4 months of treatment, 14 patients (35%) expressed a clear desire for high-carbohydrate/high-fat foods with a sweet taste. Within this group, eight patients already preferred these foods while medication-free, while six subjects demonstrated a change in preference to these foods during treatment. The other 26 patients (65%) showed no consistent changes in food preference. These results suggest that while approximately one-third of imipramine-treated patients report a preference for sweets, only 15% actually developed this preference during treatment.

Adult↗
PubMed1987

Protein consumption increases tyrosine concentration and in vivo tyrosine hydroxylation rate in the light-adapted rat retina.

The ingestion of a single, 40% protein meal increased serum and retinal tyrosine levels and stimulated retinal tyrosine hydroxylation rate in light-adapted rats. Consumption of a similar, protein-free meal elicited none of these effects. The results thus indicate for retinal dopamine neurons that physiologically induced increases in tyrosine level can readily stimulate in vivo tyrosine hydroxylation rate.

Amino Acids↗
PubMed1987

Appetite and food preference in depression: effects of imipramine treatment.

A nutritional survey, the Pittsburgh Appetite Test (PAT), was developed to study potential changes in appetite and food preference reported by patients during a depressive episode and during antidepressant treatment. We examined a group of 50 depressed outpatients who were drug-free for 2 weeks prior to treatment with imipramine and psychotherapy for 4 months. A significant increase in the desire for "sweets" (carbohydrate--fat-rich foods) was observed during a depressive episode, compared to periods when patients recalled feeling well (retrospective data). During imipramine treatment, no further changes were observed in preference for either "sweets" or carbohydrates when compared to the medication-free period. Alterations in patient self-reports of appetite and body weight change were noted during imipramine treatment.

Adult↗
PubMed1987

Twenty-four-hour variations in rat blood and brain levels of the aromatic and branched-chain amino acids: chronic effects of dietary protein content.

Groups of young adult, male rats were given free access for 12 weeks to a single diet containing either 12%, 24%, or 40% protein (dry weight). At the end of this time, six rats from each diet group were killed every four hours throughout a single 24-hour period, and blood samples and brains were obtained for quantitation of several of the large neutral amino acids (LNAAs). The blood level of each LNAA varied significantly as a function of time of day (tending to be lower during the day than at night) and as a function of dietary protein content (typically rising as protein intake increased). Except for tyrosine and valine, the serum concentration ratio of each LNAA to the sum of the other LNAA (previously reported to be a good predictor of the competitive uptake of each LNAA into brain) and the brain level of each LNAA showed unremarkable variations with time of day and dietary protein content. In contrast, the serum ratios and brain levels of tyrosine and valine did show notable variations at night as a function of dietary protein intake. Together, the results show that within a chronic physiologic range of protein intakes, the serum ratios and brain levels of several large neutral amino acids, particularly tryptophan, bear no relationship to dietary protein level. Though good correlations between these parameters and protein intake were obtained for valine and tyrosine, their physiologic/metabolic significance, if any, is unknown. In general, the data do not support the broad, unvalidated use of serum LNAA ratios in chronic settings as predictors of brain LNAA levels.

Amino Acids↗