Search PubMed⌕ Search

Biomedical subjects

S B Johnson

Publications and source records attributed to S B Johnson.

At least 127 records · Page 7Linked to original sources
PubMed1991

Obesity and weight loss alter serum polyunsaturated lipids in humans.

Serum omega 6 (n-6) fatty acids were assessed in 12 obese women during an outpatient very-low-calorie diet (VLCD). Ten subjects (S10) achieved a mean weight loss of 17 kg over 3-5 mo (initial weight-for-height 157%). Serum was obtained before (baseline) and monthly during the VLCD and from five of them (S5) after 2-3 mo of weight stability (refed) at 21 kg of loss. At baseline for S10, the serum phospholipid (PL) 20:4 omega 6 was 9.16 wt% and differed from normal (12.81 wt%) by P less than 0.0001, but cholesterol ester (CE) 20:4 omega 6 did not differ from normal. During 3 mo of VLCD, the S10 serum PL and CE 18:2 omega 6 fell (P less than 0.005 and 0.0001, respectively). Serum PL 20:4 omega 6 rose to normal during VLCD months 1-3 (P less than 0.01) while the serum CE 20:4 omega 6 rose above normal (P less than 0.0002). During the VLCD, S5 results paralleled S10. However when refed, S5 PL and CE 18:2 omega 6 and 20:4 omega 6 all reverted to baseline (PL 20:4 omega 6 below normal, P less than 0.001). Serum PL 20:4 omega 6 is low in moderate obesity, corrects to normal during a VLCD, but regresses to the predict abnormality after weight loss.

Adult↗
PubMed1991

Essential fatty acid status and fluidity of plasma phospholipids in cystic fibrosis infants.

The fatty acid (FA) patterns of cord serum phospholipids (PLs) were examined in 4 cystic fibrosis (CF) newborns, 8 non-CF siblings, and 22 normal control subjects. Plasma from 27 newly diagnosed CF infants and 38 normal infants aged less than 2 y were studied for comparison. CF cord-blood PLs had patterns similar to those of CF siblings and to normal newborns, but the pattern for CF did not shift toward adult patterns during infancy as did patterns for normal infants. CF infants at diagnosis exhibited a deficiency pattern in which 18: 2 omega 6, 20:4 omega 6, 22:4 omega 6, an omega 3 polyunsaturated fatty acids (PUFAs) were significantly subnormal and 18:3 omega 6, total saturated fatty acids, and total monounsaturated fatty acids were significantly elevated compared with normal infants. In PLs in CF infants, although mean chain length of FAs was low, mean melting point was elevated 2.4 degrees C and double-bond index was low (both P less than 0.001), implying a significantly lessened fluidity. Nutritional supplements of both omega 6 and omega 3 PUFAs are cated.

Aging↗
PubMed1991

Enhancing blood glucose awareness in adolescents and young adults with IDDM.

OBJECTIVE: To determine the effectiveness of an intervention program designed to improve blood glucose awareness. RESEARCH DESIGN AND METHODS: Eight young-adult outpatients (mean age 22 yr) and six adolescent inpatients (mean age 14.5 yr) with insulin-dependent diabetes mellitus participated in the intervention program. Nine adolescent inpatients (mean age 13.9 yr) served as an untreated comparison group. One adult outpatient with unreliable data was removed. Before treatment, each patient completed a minimum of 40 blood glucose estimations, blood glucose tests, and symptom-rating checklists. Symptoms of hypo- or hyperglycemia were identified for each patient. The three-session intervention focused on internal (e.g., personal symptoms) and external (e.g., timing and amount of insulin, food, and exercise) cues that could be used to enhance blood glucose awareness. At postintervention, patients completed a minimum of 40 additional blood glucose estimates and tests. Comparison subjects completed the pre-postassessments but did not receive the intervention. RESULTS: Blood glucose estimation accuracy was evaluated with error grid analysis. All estimated-actual blood glucose values were plotted into one of five zones: accurate estimates (zone A), benign errors (zone B), and clinically dangerous errors (zones C, D, and E). An overall accuracy index (AI) was calculated by subtracting the summed percentage of clinically dangerous estimates (zones C, D, and E) from the percentage of accurate estimates (zone A). At study entry, the adolescent inpatients' mean AI of 7% was significantly poorer than the 32% mean AI exhibited by the outpatient young-adult sample (P less than 0.02). At postintervention, the adolescents' mean AI improved to 30% (P less than 0.02) and the young adults' mean outpatient AI improved to 45% (P less than 0.06). The treated sample as a whole exhibited increased sensitivity to both hypo- (P less than 0.005) and hyperglycemia (P less than 0.05). Similar improvements did not occur in the untreated comparison sample. CONCLUSIONS: Adolescents may exhibit poorer blood glucose awareness than adults. Although this intervention program improved blood glucose awareness in both adolescent and adult patients, postintervention blood glucose estimation accuracy remained far from ideal.

Adolescent↗
PubMed1991

Methodological considerations in pediatric behavioral research: measurement.

Measurement is the critical building block underlying all science. Adequate measures should demonstrate reliability, validity, and sensitivity. Special problems associated with the selection and development of measures used in behavioral pediatric research are reviewed. These include measurement specificity, construct complexity, the illusive "gold standard," construct independence, theoretical clarity, timing of measurements, and developmental considerations. The advantages and limitations of a variety of behavioral assessment strategies are described: questionnaires, interviews, behavioral observations, permanent products, biological measures, and provider ratings. Programmatic measurement research not only improves the science of behavioral pediatrics but also has widespread clinical application.

Attitude to Health↗
PubMed1991

The Columbia-Presbyterian Medical Center decision-support system as a model for implementing the Arden Syntax.

Columbia-Presbyterian Medical Center is implementing a decision-support system based on the Arden Syntax for Medical Logic Modules (MLM's). The system uses a compiler-interpreter pair. MLM's are first compiled into pseudo-codes, which are instructions for a virtual machine. The MLM's are then executed using an interpreter that emulates the virtual machine. This design has resulted in increased portability, easier debugging and verification, and more compact compiled MLM's. The time spent interpreting the MLM pseudo-codes has been found to be insignificant compared to database accesses. The compiler, which is written using the tools "lex" and "yacc," optimizes MLM's by minimizing the number of database accesses. The interpreter emulates a stack-oriented machine. A phased implementation of the syntax was used to speed the development of the system.

Artificial Intelligence↗
PubMed1991

Brachial plexus injury: association with subclavian and axillary vascular trauma.

Proximal upper extremity (subclavian and axillary) vascular injury (SAVI) and brachial plexus injury (BPI) occur uncommonly. However, BPI may be associated with SAVI and frequently is an important determinant of long-term disability. The medical records of patients with traumatic SAVI, BPI, or both over a 5-year period were reviewed. A total of 31 patients were identified. The group was predominantly male (28 men/3 women) with a mean age of 30.5 +/- 1.8 years (range, 15-63 years). Blunt trauma accounted for 43.5% of SAVI cases and 77.8% of BPI cases. Thirteen patients (41.9%) sustained SAVI alone (group I), 10 patients (32.2%) had combined SAVI and BPI (group II), and 8 patients (25.9%) had BPI alone (group III). Subclavian and axilliary vascular injury occurred in 10 of 18 patients (55.6%) with a BPI. Brachial plexus injury occurred in 10 of 23 patients (43.5%) with a SAVI. Patients with SAVI from blunt trauma were significantly more likely to have an associated complete BPI than patients with penetrating trauma. All patients with a complete BPI (6 patients) had an associated SAVI regardless of mechanism of injury. Only one patient with a partial BPI from blunt trauma had an associated SAVI. The Injury Severity Score was significantly higher for patients in group II. An average of 2.8 and 3.3 associated injuries were observed in patients with SAVI (groups I and II) versus patients without SAVI (group III), respectively. No patient who had a complete BPI showed an improvement in neurologic status during a mean follow-up of 7.2 months. No late vascular sequelae occurred in group-III patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1990

Differential turnover of phospholipid acyl groups in mouse peritoneal macrophages.

Phospholipid acyl turnover was assessed in mouse peritoneal exudate cells which consisted primarily of macrophages. The cells were incubated for up to 5 h in media containing 40% H218O, and uptake of 18O into ester carbonyls of phospholipids was determined by gas chromatography-mass spectrometry of hydrogenated methyl esters. The uptake was highest in choline phospholipids and phosphatidylinositol, less in ethanolamine phospholipids, and much less in phosphatidylserine. Acyl groups at the sn-1 and sn-2 positions of diacyl glycerophospholipids, including arachidonic and other long-chain polyunsaturated fatty acids, acquired 18O at about the same rate. Acyl groups of alkylacyl glycerophosphocholine exhibited lower rates of 18O uptake, and acyl groups of ethanolamine plasmalogens (alkenylacyl glycerophosphoethanolamines) acquired only minimal amounts of 18O within 5 h, indicating a low average acyl turnover via free fatty acids. Pulse experiments with exogenous 3H-labeled arachidonic acid supported the concept that acylation of alkenyl glycerophosphoethanolamine occurs by acyl transfer from other phospholipids rather than via free fatty acids and acyl-CoA. The 18O content of intracellular free fatty acids increased gradually over a 5-h period, whereas in extracellular free fatty acids it reached maximal 18O levels within the first hour. Arachidonate and other long-chain polyunsaturated fatty acids were found to participate readily in deacylation-reacylation reactions but were present only in trace amounts in the free fatty acid pools inside and outside the cells. We conclude that acyl turnover of macrophage phospholipids through hydrolysis and reacylation is rapid but tightly controlled so that appreciable concentrations of free arachidonic acid do not occur.

Acylation↗
PubMed1990

Reduced adipose 18:3 omega 3 with weight loss by very low calorie dieting.

The human undergoing rapid and sustained weight loss by very low calorie dieting (VLCD) derives the majority of daily energy needs from adipose fatty acids. To evaluate the rates of metabolic utilization of individual fatty acids in humans, two groups of adult women outpatients were studied during major weight loss by VLCD. The diets used were either food or formula, providing the recommended dietary allowance for minerals and vitamins, with fat contents of 2-20 g/d. Group 1 consisted of 10 subjects [initial body mass index (BMI) 32.7, 157% of ideal body weight (IBW)] with a mean loss of 17.7 kg in 3-5 months. Group 2 consisted of 14 subjects (initial BMI 36.7, 167% of IBW) with a mean loss of 25.6 kg in 4-5 months. Adipose tissue biopsies were obtained by needle aspiration from Group 1 before and after weight loss and from Group 2 before, at the midpoint, and after weight loss. With weight loss in Group 1, the adipose tissue content of 18:1 omega 9, 18:2 omega 6, and 20:4 omega 6 did not change, but 18:3 omega 3 fell (0.67 to 0.56 wt%, p less than 0.0001) as did 20:5 omega 3 (0.08 to 0.05, p less than 0.01). Adipose tissue 22:6 omega 3 rose from 0.03 to 0.07 (p less than 0.01). In Group 2, only 18:3 omega 3 showed a change, falling from 0.71 to 0.69 to 0.59 wt% across weight loss (p = 0.03 by analysis of variance). We conclude that the major fatty acids are oxidized in proportion to their composition in adipose triglyceride.(ABSTRACT TRUNCATED AT 250 WORDS)

Adipose Tissue↗
PubMed1990

Adherence in childhood diabetes: results of a confirmatory factor analysis.

In an earlier study (Johnson, Silverstein, Rosenbloom, Carter, & Cunningham, 1986), an exploratory factor analysis identified five components of adherence in childhood diabetes. In this investigation, a simultaneous confirmatory analysis was used to test the equality of this factor pattern across two independent samples. Factors 1 through 4--Exercise, Injection, Diet Type, and Eating/Testing Frequency-were confirmed. Factor 5--Diet Amount--proved to be too complex; the adherence measures comprising this factor (total calories and concentrated sweets consumed) are best treated as separate, single-indicator constructs. The results support a multivariate conceptualization of adherence, offer insight into the nature of the components underlying diabetes adherence, and provide measurement information for reliable component estimation.

Adolescent↗
PubMed1990

Reduced arachidonate in serum phospholipids and cholesteryl esters associated with vegetarian diets in humans.

Lipid fractions such as phospholipids (PLs), cholesteryl esters (CEs), and free fatty acids (FFAs) represent source pools for eicosanoid synthesis. To determine whether dietary habits affect the enrichment of 20:4n-6 in these precursor pools, we studied humans with partial or complete arachidonate restriction resulting from chronic avoidance of animal fat and tissue. Fasting serum was obtained from omnivorous control subjects (Omni, n = 100), semivegetarians (Semiveg, n = 16), and vegetarians (Veg, n = 25). PLs, CEs, FFAs, and triglyceride (TG) fatty acids were quantitated by thin-layer and gas chromatography. Serum 20:4n-6 was lower in the PL fraction in both Veg (p less than 0.01) and Semiveg groups (p less than 0.05) than in the Omni group and lower in the CE fraction in the Veg group (p less than 0.05). Serum 18:2n-6 did not differ between groups for any serum lipid fraction. 18:3n-3 was elevated in PLs and CEs of both Veg (p less than 0.05 and 0.01) and Semiveg groups (p less than 0.05 and 0.01) compared with the Omni group but did not result in differences in 20:5n-3 in PLs or CEs between diet groups. The lower concentration of 20:4n-6 in serum PLs and CEs of the Veg group indicates that dietary arachidonic acid enriches its circulating pool in humans; however, 20:5n-3 is not similarly responsive to dietary restriction.

Adult↗
PubMed1990

Assessing daily diabetes management by 24-hour recall interview: the validity of children's reports.

The current investigation examined the accuracy of diabetic children's 24-hr recall data by comparing the 7- to 12-year-old children's reports to direct observations of their behavior. Observers' data evidenced sufficient reliability to serve as an acceptable standard to which the children's 24-hr recall data could be compared. The children exhibited excellent agreement with the observers' data on all measures of the occurrence/nonoccurrence of events, including insulin injections, exercise periods, glucose tests, meal, type and amount of insulin injected. Although somewhat poorer reporters on some behaviors, differences were small. Children underreported most dietary behaviors and some exercise behaviors.

Blood Glucose Self-Monitoring↗
PubMed1990

Unintentional injury death rates in rural Appalachia.

Rural unintentional injury (UI) death rates are higher than rates for urban regions. Our trauma center serves 49 rural Appalachian (AP) counties in a 120-county rural state. We investigated the impact of prehospital and hospital resources on UI death rates in our referral area. Age-adjusted and average age- and sex-specific UI death rates from 1979-1985 were compared among 49 rural AP counties, the 71 non-Appalachian (NAP) counties, and the United States. Counties were grouped for comparisons by level of prehospital care (Advanced Life Support [ALS] vs. Basic Life Support [BLS]) and by presence (H) or absence (NH) of a hospital. Death rates were calculated using data from the 1980 population census, the National Center for Health Statistics (NCHS), and state vital statistics. Within AP, all 49 counties have ambulance service. Only 9/49 (18%) have ALS service and 13/49 (26%) have no hospital. Age-specific AP rates were higher than NAP and US rates in the 25-44 and 45-64 year age groups. AP death rates were highest for BLS and NH counties across all age groups. Rural UI death rates in the region remain unacceptably high. The reason(s) that AP death rates exceed the NAP rates is uncertain. ALS service and an available hospital were associated with lower death rates. We propose both educational and epidemiologic programs to better identify and define additional problems.

Adult↗
PubMed1990

Psychological impact of islet cell-antibody screening. Preliminary results.

The identification of at-risk individuals before the onset of insulin-dependent diabetes mellitus with islet cell-antibody (ICA) screening programs could have significant psychological sequelae. We initiated a descriptive study of ICA+ subjects and their family members in which reactions to study participation, anxiety, and coping responses are monitored. Described here are preliminary results from 18 ICA+ youngsters, 6 ICA+ adults, and their family members. ICA+ identification resulted in clinically significant anxiety that dissipated to normal levels over time for all participants. Both ICA+ subjects and family members coped with the news in similar ways, relying primarily on problem-focused and social-support coping strategies. Few blamed themselves for their own or their loved one's ICA+ status. There was some evidence that the ICA+ participants may minimize the potential impact of their at-risk status. Compared with family members, ICA+ subjects used more avoidance coping strategies, and few believed they would ever develop diabetes. In contrast, many family members believed their loved one would ultimately develop diabetes. Although the initial findings support the resiliency of this population, the long-term effects of ICA screening remain to be seen.

Adaptation, Psychological↗
PubMed1990

Adherence-health status relationships in childhood diabetes.

Used 24-hr recall interviews to assess adherence in a sample of seventy-eight 6- to 19-year-olds with insulin-dependent diabetes mellitus over a 3-month period. Thirteen adherence measures were quantified and grouped into six adherence factors (Injection, Exercise, Diet Type, Testing/Eating Frequency, Calories Consumed, and Concentrated Sweets). Prevailing glucose levels over a 2- to 3-month interval were indexed by glycosylated hemoglobin A1c (HA1c) and glycosylated serum protein (GSP) assays. Fasting triglycerides (TRIG) and total cholesterol (CHOL) assays were used to estimate lipid metabolism. Adolescents were generally less adherent than their young counterparts. Using hierarchical multiple-regression techniques, HA1c and GSP were not reliably predicted by most of the adherence factors; only Calories Consumed showed any predictive power. No significant regression equations emerged for CHOL. In contrast, TRIG was significantly associated with five of the six adherence factors; in all cases, adherence interacted with the patients' metabolic status (as defined by HA1c) at study entry, suggesting that adherence had different effects for youngsters in good versus poor diabetes control.

Adolescent↗
PubMed1989

Fatty acid pattern of tissue phospholipids in copper and iron deficiencies.

Because copper and iron have been reported to be essential cofactors in delta 9 desaturation of fatty acids, the effects of different dietary intakes of copper and iron on tissue fatty acids were studied. Male Long-Evans rats (ten per group) were fed diets containing adequate, deficient or excess copper or iron. On day 42 of the dietary regimen, the animals were killed and tissues and blood were removed for analysis of metals and fatty acids of phospholipids. Compared with the copper-adequate rats, the copper-deficient rats showed increased 18:0 in liver and decreased 16:1 omega 7 in liver, heart and serum. There were no differences for 16:0 or 18:1 omega 9. Intake of excess copper did not cause an increase in products of delta 9 desaturation. Comparisons between iron-deficient and iron-adequate rats showed that iron deficiency increased 18:2 omega 6 in liver and serum and decreased 20:4 omega 6 in serum only. Relative percentages of 16:0, 18:0, 16:1 omega 7 and 18:1 omega 9 in liver and serum phospholipids were similar for both groups. Intake of excess iron caused a decrease in 18:2 omega 6; and 16:0 and 18:1 omega 9 were higher in the liver of the iron-excess group than the iron-deficient group. This study did not support the requirement for copper or iron in the delta 9 desaturation of fatty acids as expressed in phospholipids of liver, heart and serum.

Animals↗
PubMed1989

Deficiencies of polyunsaturated fatty acids and replacement by nonessential fatty acids in plasma lipids in multiple sclerosis.

Fatty acid compositions of plasma phospholipids, cholesteryl esters, triacylglycerols, and nonesterified fatty acids of 14 clinically proven and graded cases of multiple sclerosis were determined by capillary gas chromatography and compared with the values obtained for 100 normal, healthy subjects. In phospholipids, linoleic acid (18:2 omega 6; 18 carbon atoms, 2 double bonds, 6 carbon atoms beyond last double bond) was normal and 18:3 omega 6 was increased, but all subsequent omega 6 acids were subnormal (P less than 0.001), indicating impairment of chain elongation. All omega 3 acids were subnormal. The paucity of polyunsaturated fatty acids was compensated mass-wise by an increase in saturated acids. Disproportionate increases in short-chain, saturated, and monounsaturated acids, decreases in long-chain homologs, and increases of branched and odd-chain acids were observed. Loss of polyunsaturated fatty acids and replacement by nonessential acids lowered mean chain length and raised mean melting point significantly, suggesting that lowered membrane fluidity was only partially compensated by endogenous synthesis of lower-melting, nonessential acids. This phenomenon was not observed in cholesteryl esters or triacylglycerols. Nonesterified fatty acids showed significant changes in pattern of possible autacoid precursors. The abnormal profile of fatty acids in multiple sclerosis has features in common with profiles of other syndromes involving viral infections.

Adult↗