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Biomedical subjects

S B Johnson

Publications and source records attributed to S B Johnson.

At least 145 records · Page 8Linked to original sources
PubMed1989

Psychological and physiological responses to acute laboratory stressors in insulin-dependent diabetes mellitus adolescents and nondiabetic controls.

Thirty 11- to 18-year old adolescents with insulin-dependent diabetes mellitus (IDDM) of at least 1-year duration and 15 nondiabetic controls were subjected to three laboratory stressors: a venipuncture and two public-speaking tasks. Half of the IDDM participants were in good metabolic control prior to the inception of the experiment and half were in poor control. The IDDM adolescents in poor control and the nondiabetics were matched to the well-controlled IDDM group on the basis of age, sex, and race. The two IDDM groups were also matched on disease duration. Self-report, behavioral, and physiological measures of anxiety or arousal were monitored during the stress.

Adolescent↗
PubMed1988

Composition of mixed octadecadienoates via ozonolysis, chromatography and computer solution of linear equations.

An approach to the analysis of 55 possible nonconjugated positional isomers of octadecadienoic acid is described and tested with mixtures of individual synthetic methyl esters. In the first example, by ozonolysis a seven-component mixture consisting of cis,cis 5,12-, 6,10-, 6,11-, 6,12-, 7,12-, 8,12-, and 9,12-octadecadienoates was converted to aldehydes, aldehyde-esters and dialdehydes. These fragments were separated on a 50 m X 0.2 mm free fatty acid phase (FFAP) vitreous silica capillary column. Equations for an arbitrarily restricted 12 X 15 matrix of linear simultaneous equations and a computer solution of the matrix provided the composition of the initial methyl octadecadienoate mixture. The power and significance of this method became apparent with the observation that only two of the seven isomers in the known mixture were resolved as single peaks by state-of-the-art capillary gas chromatography, but all seven were identified and estimated with acceptable error by the ozonolysis-capillary gas chromatography-computer procedure. In a generalized approach to the analysis of the 55 possible nonconjugated isomers, a computer program selects the appropriate matrix of linear simultaneous equations based on the aldehyde data supplied by the analyst. Twenty of 21 combinations of seven isomeric esters taken five at a time have been analyzed to assess the efficiency of the method. To illustrate applicability at this stage of development, the method has been used to analyze the diene products of the hydrazine reduction of gamma-linolenic acid and the diene products from the biological desaturation of isomeric monoenes.(ABSTRACT TRUNCATED AT 250 WORDS)

Chromatography, Gas↗
PubMed1988

Polyunsaturated fatty acids of serum lipids in myocardial infarction.

Two groups of volunteers had blood drawn for serum analysis of fatty acids. The first group was comprised of patients admitted to the hospital with possible myocardial infarction (MI). Blood was drawn at admission and at 12, 24 and 48 hr. These patients were subsequently divided into three groups, those with MI, those without (No MI) and those taking prostaglandin inhibitors (PGI), on the basis of the cardiac enzymes, electrocardiograms and clinical history. A fourth group of Normal nonstressed people was also drawn at 0, 12, 24 and 48 hr for comparison. Fatty acid composition of phospholipids (PL), nonesterified fatty acids (NEFA), triglycerides (TG) and cholesteryl esters (CE) was determined by capillary gas chromatography (GC), and comparisons were made between the MI, No MI, PGI and Normal groups. Total NEFA were significantly elevated in patients admitted for possible MI compared with Normals. Those patients with MI had marginally higher levels of NEFA than the No MI group at each sampling time, but this difference was not statistically significant. The MI, No MI and PGI groups had significantly different fatty acid patterns in NEFA with reduced percentages of arachidonic acid (AA) than controls. The fatty acid patterns in the four lipid classes showed few significant differences comparing the MI, No MI and PGI groups. The regular use of prostaglandin inhibitors before hospitalization for chest pain was associated with a reduced frequency of MI (p less than 0.002). NEFA levels, nonesterified AA levels and fatty acid patterns in this group did not differ from those patients not taking prostaglandin inhibitors.

Arachidonic Acid↗
PubMed1988

Determination of ester carbonyl 18O/16O ratios in phospholipids by gas chromatography-mass spectrometry.

A method is described for the quantitation of 18O enrichment in phospholipid acyl groups. Methyl esters are prepared by transesterification with sodium hydroxide in methanol and are hydrogenated prior to gas chromatography-mass spectrometry (GC-MS). Estimation of 18O content of the resulting esters is made using the m/z 74 and m/z 76 fragments, which contain both the ester oxygens. The accuracy of the method is demonstrated with synthetic methyl esters and phosphatidylcholines containing a known amount of 18O.

Carbon Isotopes↗
PubMed1988

Effects of biotin deficiency on serum fatty acid composition: evidence for abnormalities in humans.

In three patients who developed biotin deficiency during parenteral alimentation, serum fatty acid compositions of the four major lipid classes (phospholipid, cholesteryl ester, triglyceride and free fatty acid) were measured. Relative to the normal range, percent compositions of an odd-chain fatty acid (either 15:0 or 17:0 or both) were increased in each class of lipid, and these abnormalities generally returned to normal or decreased toward normal with biotin therapy. Abnormalities in particular fatty acids in the omega 6, omega 3 and omega 9 pathways were also found, but these abnormalities did not resolve with biotin therapy. These data provide evidence in favor of the conclusion that biotin deficiency causes increases in the composition of some odd-chain fatty acids in humans, perhaps by the same mechanism that leads to odd-chain fatty acidemia in the inborn deficiency of the biotin-dependent enzyme propionyl-CoA carboxylase.

Acetyl-CoA Carboxylase↗
PubMed1988

Effects of biotin deficiency on plasma and tissue fatty acid composition: evidence for abnormalities in rats.

Abnormalities of fatty acid composition have been detected in the plasma of patients who developed frank biotin deficiency during parenteral nutrition. We sought to determine which abnormalities of fatty acid composition, if any, would be replicated in the biotin-deficient rat and to determine the relative temporal relationships of these abnormalities to biotin nutritional status. We measured fatty acid compositions of the phospholipids extracted from plasma, heart, and liver and assessed biotin nutritional status longitudinally in biotin-deficient and biotin-treated rats during progressive biotin deficiency. In the biotin-deficient group, significant increases relative to the biotin-treated group were detected in all three tissues in the odd-chain fatty acids 15:0 and 17:0. In the biotin-deficient rats, significant increases in 18:2 omega 6 in liver and 18:3 omega 6 in plasma and liver and significant decreases in 22:5 omega 6 were detected in plasma and liver. The constellation of fatty acid abnormalities observed in the biotin-deficient rats was not identical to that observed in biotin-deficient patients, but abnormalities in composition of odd-chain fatty acids were detected in both human and rat and therefore are attributable to biotin deficiency per se. The abnormalities in fatty acid composition were already present by wk 4 on the egg white diet; the cutaneous findings appeared between wk 3 and 6. These observations are consistent with the hypothesis that an abnormality in fatty acid metabolism may play a pathogenetic role in the cutaneous manifestations of biotin deficiency.

Animals↗
PubMed1987

Essential fatty acid status in isolated closed head injury.

Abnormal profiles of polyunsaturated fatty acids in the plasma phospholipid fraction were observed in 14 patients with hypermetabolism due to severe isolated closed head injury. Depressed linoleic acid levels were observed within 24 hours along with elevation of oleic acid levels. By one week postinjury, subnormal levels of arachidonic acid were also observed. These data indicate that the metabolic response to injury encompasses changes in the metabolism of polyunsaturated fatty acids which are rapid in onset and qualitatively similar to those seen in mild essential fatty acid deficiency.

Adult↗
PubMed1987

Rhabdomyolysis in retrospect: are psychiatric patients predisposed to this little-known syndrome?

Rhabdomyolysis is a potentially lethal syndrome that follows skeletal muscle injury, both traumatic and nontraumatic. The literature on this syndrome remains sketchy, and rhabdomyolysis may often go unrecognized. The history, clinical presentation, laboratory findings, etiology, and treatment of rhabdomyolysis are reviewed. Factors which predispose psychiatric patients in particular to this syndrome are discussed. Recommendations to reduce morbidity and mortality are offered.

Acute Kidney Injury↗
PubMed1986

A comparison of pyrrolidide and picolinyl ester derivatives for the identification of fatty acids in natural samples by gas chromatography-mass spectrometry.

The pyrrolidide and picolinyl ester derivatives of the fatty acids in two natural lipid samples rich in unsaturated fatty acids, pig testis lipids and cod liver oil were satisfactorily resolved on capillary columns of fused silica coated with stationary phases of varying polarity. The picolinyl esters, in particular, when subjected to gas chromatography-mass spectrometry on a column containing a cross-linked methyl silicone, gave distinctive mass spectra, which could be interpreted in terms of both the numbers and positions of the double bonds.

Animals↗
PubMed1986

Behavioral interventions for childhood nocturnal enuresis: the differential effect of bladder capacity on treatment progress and outcome.

Study participants were fifty 5- to 13-year-old children (33 boys and 17 girls) with nocturnal enuresis of at least 3 months duration. All wet their beds at least twice per week, were of normal intelligence, and were without demonstrable organic cause for their enuresis. Each youngster's pretreatment maximum functional bladder capacity (MFBC) was used to classify the child as having small or large MFBC based on available norms. Youngsters were then randomly assigned to treatment with the urine alarm (UA) alone or with the urine alarm supplemented with retention control training (UA plus RCT). Of the 40 youngsters who completed treatment, 37 (92.5%) achieved the treatment goal of 14 consecutive dry nights. Two additional children became dry during follow-up, leaving only one child who failed to stop wetting. Sixteen children (41%) subsequently relapsed, but all who reentered treatment became dry. Because treatment outcome was uniformly excellent across all groups, treatment progress was evaluated by analyzing wetting frequency and arising at night to use the bathroom during treatment, as well as prechange and postchange in MFBC For both wetting frequency and arising at night, there was a significant interaction between bladder capacity and treatment. Small MFBC children treated with the UA plus RCT and large MFBC youngsters treated with the UA alone had the fewest wetting episodes and got up at night to use the bathroom less often; these youngsters took less time to be successfully treated. Prechanges and postchanges in MFBC indicated that RCT did not lead to consistent increases in bladder capacity in the sample studies. The 10 children who terminated treatment prematurely had lower self-esteem and more parent-reported conduct problems than the 40 children who completed treatment.

Adolescent↗
PubMed1986

Partial correction by exogenous lipid of abnormal patterns of polyunsaturated fatty acids in plasma phospholipids of stressed and septic surgical patients.

Polyunsaturated fatty acid (PUFA) profiles are abnormal in a variety of clinical conditions that are commonly seen in the surgical intensive care unit. PUFA profiles in the serum phospholipids were studied by capillary gas chromatography in 22 critically ill, hypermetabolic surgical intensive care unit patients. All patients received continuous total parenteral nutrition (TPN) by central vein with trace elements and vitamins. Eleven patients received daily supplementation with 50 gm of safflower oil-based lipid emulsion (TPN + L group). No lipid was administered in the other 11 patients (TPN). Both groups showed deficiencies in 18:2 omega 6 linoleic acid from the time of onset of TPN. In TPN the deficiency was progressive; in the TPN + L group, lipid administration prevented this progression but did not restore 18:2 omega 6 levels to normal. In the TPN group levels of 18:1 omega 9 and its metabolite 20:3 omega 9 (the triene of deficiency) increased over time, consistent with a mild essential fatty acid deficiency. These changes in omega 9 acids were not seen with lipid supplementation. Despite low levels of 18:2 omega 6 in both groups, the levels of omega 6 metabolites were normal or increased. Levels of 20:4 omega 6 (arachidonate) remained normal or slightly decreased in the TPN group but were decreased in the TPN + L group. Levels of arachidonate metabolites, in particular 22:5 omega 6, were increased in the lipid-supplemented group. We concluded that stressed patients receiving TPN develop mild essential fatty acid deficiency that is only partially correctable by lipid supplementation and that administration of supplemental lipid to these patients stimulates arachidonic acid conversion to 22:5 omega 6.

Aged↗
PubMed1986

Essential fatty acid patterns in preeclampsia.

Fatty acid patterns were determined for maternal and cord sera from normal and preeclamptic pregnancies using gas liquid chromatography. Ten normal and 11 preeclamptic maternal sera were used; 6 preeclamptic and 6 normal cord sera were measured. Fatty acid patterns were measured in the nonesterified fatty acids (NEFA), the triglycerides (TG), the cholesterol esters (CE), and the phospholipids (PL). Preeclampsia showed significant differences in the essential fatty acid patterns in the maternal and cord sera compared to normal pregnancy. Oleic acid, an early indicator of essential fatty acid deficiency, made up a significantly greater proportion of preeclamptic cord blood NEFA, TG, and PL than in normal cord blood. Abnormalities in essential fatty acid patterns may be associated with decreased prostacyclin production and dysmaturity which may be seen with preeclampsia.

Arachidonic Acid↗
PubMed1986

A case of massive rhabdomyolysis following molindone administration.

Rhabdomyolysis is a potentially lethal syndrome that psychiatric patients seem predisposed to develop. The clinical signs and symptoms, typical laboratory features, and complications of rhabdomyolysis are presented. The case of a schizophrenic patient is reported to illustrate massive rhabdomyolysis and subsequent acute renal failure following molindone administration. Physicians who prescribe molindone should be aware of this reaction.

Acute Kidney Injury↗
PubMed1985

Sister chromatid exchanges in adult epileptic patients on phenytoin therapy.

Sister chromatid exchanges (SCE) were studied in lymphocyte cultures of 12 adult male epileptic patients on long-term monotherapy with phenytoin (PHT) and of matched controls. Significantly increased frequency of SCE was observed in the epileptic patients as a group and in almost all individuals, indicating a detectable chromosome damaging effect of PHT therapy on its human users.

Adult↗