Incorporation, distribution, and turnover of arachidonic acid within membrane phospholipids of B220+ T cells from autoimmune-prone MRL-lpr/lpr mice.

The metabolism of AA-containing phosphoglycerides within T cell membranes leads to the generation of second messengers that appear to play a crucial role in transmembrane signal transduction. To test the hypothesis that aberrations in the movement of arachidonoyl-phospholipids are associated with and may potentially contribute to abnormal T cell function, the incorporation, distribution, and turnover of AA within the membrane glycerolipids of cells that are known to exhibit immunoregulatory disturbances was examined. Thy-1+, Ly-1+, L3T4-, Lyt-2-, B220+ T cells from autoimmune MRL-lpr/lpr mice were used as the cellular model. In contrast to control lymph node T cells, which preferentially incorporate labeled AA into phosphatidylcholine (PC), B220+ T cells displayed a predilection for distributing [3H]arachidonate into phosphatidylinositol (PI). The arachidonoyl-phospholipid pools were normal in B220+ T cells. The constitutive turnover of [3H]arachidonoyl-PI was significantly enhanced and that of [3H]arachidonate-PC substantially reduced in B220+ T cell compared with control cells. Using membrane homogenates B220+ T cells demonstrated a functional increase in the levels of lyso-PI. Intact B220+ T cells prelabeled with [3H]myoinositol and cultured in the absence of stimulation with exogenous antigens or mitogens, exhibited increased production of lyso-PI. The data indicate that the preferential formation of [3H]arachidonoyl-PI in B220+ T cells is the result of greatly increased, constitutive PI turnover that appears to be due to a membrane phospholipase A2 activity. It remains possible that disturbances in the movement of arachidonate within phospholipids of B220+ T cells play a role in the expression of aberrant immunological activity.

Aberrant production of leukotriene C4 by macrophages from autoimmune-prone mice.

Eicosanoids have been implicated in the pathogenesis of autoimmune diseases. In this study, peritoneal macrophages from autoimmune-prone mice were examined for their capacity to produce proinflammatory 5-lipoxygenase metabolites. The results indicate that enhanced production of leukotriene C4 is a common feature of murine autoimmunity and suggest further that aberrations in 5-lipoxygenase activity may play a role in the development of lupus.

Evidence for participation of cytochrome b5 in microsomal delta-6 desaturation of fatty acids.

The delta-6 desaturation of linoleic acid to gamma-linolenic acid and oleic acid to 6,9-octadecadienoic acid by rat liver microsomes was investigated. Using a specific antibody prepared against purified rat liver cytochrome b5, we demonstrated that cytochrome b5 participated in delta-6 desaturation of both fatty acids. The reaction products were identified as their methyl ester derivatives by argentation thin-layer chromatography, gas-liquid chromatography, and reductive ozonolysis followed by gas-liquid chromatography.

Stimulation of the microsomal alkylglycerol monooxygenase by catalase.

Liver cytosol contains a heat-sensitive nondialyzable soluble factor necessary for maximal activity of the alkylglycerol monooxygenase present in rat liver microsomes. In this report, we demonstrate that the stimulatory component in rat liver supernatant is catalase. Catalase functions to protect the enzyme from inactivation by H2O2 in addition to its documented ability to retard the noenzymatic oxidation of the pterin cofactor. The protective effect of catalase on alkylglycerol monooxygenase and on the aromatic amino acid hydroxylase systems indicates that H2O2 sensitivity is a general feature of pterin-dependent hydroxylases.

A novel approach to improve undergraduate surgical teaching.

BACKGROUND: Undergraduate surgery is at an important crossroads. Many departments report significant difficulties delivering effective teaching. Our student feedback indicated a dated surgical curriculum lacking structure, quality and uniformity. We report on a new "blended" approach employing a combination of professional DVDs, case based discussions, online material and traditional bedside teaching designed to provide structure, standardization, and equality of learning . METHODS: Year 4 students who had undertaken the new course and year 5 students who had participated in the traditional teaching programme were compared. Students completed a 20 item questionnaire about their experiences of the surgical teaching programme. RESULTS: One hundred and seventy-one year 4 (70%) and 148 year 5 students (66%) responded. Domains relating to "Overall Satisfaction with the course", "Approval of innovative teaching methods and interactivity" and "Satisfaction with the clarity of course information" showed improvements when comparing the new and old programmes. However bedside teaching was not rated as highly in the new programme (p<0.05). CONCLUSION: This blended approach has resulted in improved student understanding and engagement. The apparent compromise of bedside teaching may be a reflection of higher expectations. We believe that a similar blended approach has the potential to re-invigorate surgical teaching elsewhere.

Fever and petechiae in children.

A prospective study of patients with fever and petechiae was performed. Of 190 patients enrolled in the 1-year study, 13 (7%) had meningococcal disease. The most common bacterial association was Streptococcus pyogenes (19 patients). Viral infections were documented in 28 patients. Patients with invasive bacterial disease (group I) appeared more sick, were more likely to have signs of meningeal irritation, and were more likely to have petechiae on the lower extremities than those with less serious, nonbacteremic disease (group II). No patient in group I had petechiae only above the nipple line. Patients in group I had a significantly higher peripheral white blood cell count and absolute band form count. Although no laboratory test or physical finding was sufficiently sensitive to detect all patients with serious disease, the patient with abnormal cerebrospinal fluid, elevated white blood cell count, or elevated absolute band form count was at increased risk for invasive, bacterial disease. Conversely, the risk of serious disease was small if all of these values were in the normal range in the nonill-appearing child or if sore throat and clinical pharyngitis were present in the patient older than 3 years of age.

Severity of disease correlated with fever reduction in febrile infants.

A prospective study of the effects of fever reduction on the clinical appearance of infants at risk for occult bacteremia was undertaken to study the hypothesis that infants with bacteremic illness fail to improve clinically following defervescence compared with infants with benign viral illness. A total of 154 children were enrolled in the study, including 19 with bacteremia: 13 with occult Streptococcus pneumoniae bacteremia, two with occult Haemophilus influenzae, type b bacteremia, and four with Haemophilus meningitis and bacteremia. There were no differences in degree of temperature reduction with acetaminophen between the bacteremic and nonbacteremic groups of infants. Among infants with bacteremia but without meningitis, differences from nonbacteremic children were detected in clinical appearance prior to fever reduction but not following defervescence. All patients with meningitis appeared seriously ill before and after defervescence. It was concluded that clinical improvement with defervescence is not a reliable indicator of the presence of occult bacteremia. Lack of clinical improvement with defervescence may be a reliable indicator for the presence of meningitis. Because there were differences in clinical appearance prior to fever reduction, routine administration of acetaminophen may interfere with the clinical evaluation by the physician.

The effects of drugs on Sephadex-induced eosinophilia and lung hyper-responsiveness in the rat.

1. Rats given an intravenous injection of Sephadex particles (0.5 mg of G200 in 1 ml of saline) on days 0, 2 and 5 had a blood eosinophilia which was maximal on day 7. 2. On day 7, broncho-alveolar lavage (BAL) fluids taken from the rats contained an increased number of eosinophils and fewer mononuclear cells but there was no change in the small number of neutrophils. In addition the rats were hyper-sensitive to the increase in resistance to artificial respiration produced by 5-hydroxytryptamine (5-HT), given intravenously, with a shift to the left of the log dose-response curve. Lung parenchymal strips, taken from the rats on days 6, 7 and 8, were hyper-reactive to 5-HT with an increase in slope of the log dose-response curve. 3. Compounds with a wide variety of activities were evaluated for their effects on the blood eosinophilia on day 7 when given before each injection of Sephadex. The eosinophilia was reduced by glucocorticosteroids, beta-adrenoceptor agonists, aminophylline, dapsone and phenidone. 4. Dexamethasone, isoprenaline, dapsone and phenidone at doses that reduced the blood eosinophilia also reduced the changes in number of leucocytes in the BAL fluids and the hyper-responsiveness to 5-HT in vivo and in vitro, except that the effects of dapsone on the hyper-sensitivity to 5-HT in vivo did not reach significance. Aminophylline was the least effective of the drugs at reducing the blood eosinophilia and its effects on the other changes did not reach significance. Sodium cromoglycate reduced the BAL eosinophilia but had no effect on the other changes produced by Sephadex. 5. The correlation coefficients between blood eosinophil numbers and reactivity to 5-HT in vitro and sensitivity in vivo were r = 0.76, (n = 88; P < 0.001) and r = 0.53, (n = 61; P < 0.001) respectively. 6. Doses of dexamethasone, isoprenaline, dapsone and phenidone that reduced the blood eosinophilia when given before each injection of Sephadex were inactive when given up to 8 h after the Sephadex. 7. These data show an association between blood eosinophilia and hyper-responsiveness of the lung. The blood eosinophilia in the rats was triggered within the first few hours of injecting the Sephadex and drugs have been identified which inhibit this trigger.

Limited heterogeneity of HIV type 1 in infected mothers correlates with lack of vertical transmission.

The human immunodeficiency virus type 1 (HIV-1) envelope V3 region sequences of peripheral blood mononuclear cell DNA were analyzed from three nontransmitting mothers (infected mothers who failed to transmit HIV-1 to their infants in the absence of antiretroviral therapy), including one mother with two deliveries, and compared with the sequences of seven previously analyzed transmitting mothers. The coding potential of the envelope open reading frame, including several patient-specific amino acid motifs and previously described molecular features across the V3 region, were highly conserved. There was a low degree of heterogeneity within the sequences of each nontransmitting mother compared with the sequences of transmitting mothers. In addition, the estimates of genetic diversity of nontransmitting mother sequences were significantly lower compared with transmitting mother sequences. Phylogenetic analysis showed that the sequences of each nontransmitting mother formed distinct clusters that were well discriminated from each other and the sequences of seven transmitting mothers. In conclusion, a low degree of HIV-1 genetic heterogeneity in these infected mothers correlates with lack of vertical transmission; this finding may be useful in developing strategies for further prevention of maternal-fetal transmission.

Comparison of 1% and 2.5% selenium sulfide in the treatment of tinea capitis.

OBJECTIVE: To determine whether an over-the-counter shampoo containing 1% selenium sulfide would have sporicidal activity equal to that of a 2.5% selenium sulfide prescription lotion in the adjunctive treatment of tinea capitis infection. DESIGN: Prospective randomized nonblinded clinical trial. SETTING: Outpatient clinics and emergency department of a children's hospital. PATIENTS: Fifty-four patients between the ages of 1 and 15 years with culture-proved tinea capitis infection caused by Trichophyton tonsurans enrolled during a 14-month period. METHODS: Patients were randomized to receive 2.5% selenium sulfide lotion, 1% selenium sulfide shampoo, or a bland, nonmedicated shampoo with which they were instructed to shampoo twice weekly. All received 15 mg/kg per day of griseofulvin. Dermatophyte cultures of the affected area of each patient's scalp were obtained on enrollment and every 2 weeks until a negative culture was obtained from a previously infected area. RESULTS: Survival data analysis demonstrated that both the 2.5% selenium sulfide and 1% selenium sulfide preparations were superior to the nonmedicated control shampoo in terms of the time required to eliminate shedding of viable spores. When compared with each other, there was no difference between the 2.5% selenium sulfide and 1% selenium sulfide preparations in time required to produce a negative culture. CONCLUSION: Commercially available 1% selenium sulfide shampoo is an equally effective yet less expensive alternative sporicidal therapy in the adjunctive treatment of tinea capitis infection.

After-hours telephone triage and advice in private and nonprivate pediatric populations.

OBJECTIVES: To compare the content of after-hours medical triage and advice calls regarding private practice patients vs nonprivate practice patients and to assess caregiver compliance with advice resulting from these calls. DESIGN: Survey of after-hours medical triage and advice calls during a 2-week period (September 1 through 15, 1996). SETTING: Three private practices (serving approximately 24 000 patients) and 1 urban hospital-based, non-private practice (serving approximately 12 000 patients). SUBJECTS: After-hours medical triage and advice calls from caregivers of patients receiving their primary care in these settings. MAIN OUTCOME MEASURE: Compliance with recommended emergency department (ED) or office visit referrals. RESULTS: A total of 286 calls regarding private practice patients and 377 calls regarding nonprivate practice patients were received (P<.001). Eighty-one calls were referred by the nurse directly to the physician. Fifty-nine private practice patients and 59 nonprivate practice patients were referred to the ED. Caregivers of 94 private practice patients and 132 nonprivate practice patients were given home treatment advice. Appointments to be seen at their primary care source were given for 78 private practice patients and 160 nonprivate practice patients. Non-private practice patients were more likely to be referred for office care (P=.005); private practice patients were more likely to be referred to the ED (P=.01). Compliance with ED referrals was 42% for patients of nonprivate practice and 46% for private practice; for office visit referrals, compliance was 64% for nonprivate practice and 69% private practice patients (P=.71 for compliance with ED referrals and P=.40 for compliance with office referrals). CONCLUSIONS: Compliance with recommended physician encounters was not significantly different (and lower than expected) in both groups of patients. Private practice patients are more likely to be referred to the ED. Calls for nonprivate practice patients are more frequent and these patients are more likely to be referred to their primary care source. This difference may be due to caregivers of patients from nonprivate practices seeking advice for less serious conditions. Physicians should address telephone medicine with caregivers proactively during health maintenance visits.

An unusual iatrogenic cause of right coronary air embolism.

A 62-year-old woman undergoing redo mitral valve replacement was noted to have persistent intracardiac air following standard deairing procedures. Transesophageal echocardiography (TEE) identified air bubbles entering the left atrium from the right superior pulmonary vein. Exploration of the pleural cavity revealed a fistula between the pulmonary parenchyma and the right superior pulmonary vein caused by the atriotomy closure suture transfixing the edge of the lung, which was repaired with immediate disappearance of the air emboli. This demonstrates that transesophageal echocardiography is an invaluable aid to ensuring complete deairing after open heart procedures.

Genetic brain polypeptide variants in inbred mice and in mouse strains with high and low sensitivity to alcohol.

Twelve genetically determined brain polypeptide charge variants were identified by comparing cerebellar vermis of 7 inbred mouse strains and of mice selectively bred from 8 strains closely related to these 7 ancestral strains and one other for acute behavioral sensitivity to the sedative effects of ethanol. The selectively bred ethanol-sensitive (LS, long sleep) and insensitive (SS, short sleep) mice exhibited different allelic variants at 6 of these 12 gene loci expressed in the cerebellum. Variant polypeptide A1 (81 kdalton, pI 5.6) was shown to be associated with the membrane of synaptosomal mitochondria and to exhibit a basic variant in SS mice that is determined by a dominant allele. Other variant polypeptides showed codominant inheritance in F1 crosses. However, the phenotype of no single one of these brain polypeptides consistently correlated with the ethanol behavioral sensitivity of the 7 inbred mouse strains nor of 8 recombinant inbred (B X D, C57BL X DBA) strains. This finding supports the hypothesis that a substantial amount of inbreeding, leading to random fixation of alleles independent of selection for ethanol sensitivity, occurred during the breeding of the SS and LS mice. The present findings of a lack of a strong association between sleep time and a brain polypeptide variant do not preclude the existence of a major gene effect contributing to variation in acute sensitivity to ethanol but are consistent with reports that multiple loci are responsible for the difference in ethanol sensitivity between SS and LS mice.(ABSTRACT TRUNCATED AT 250 WORDS)

Activation of phospholipase D in porcine tracheal smooth muscle: role of phosphatidylinositol 3-kinase and RhoA activation.

Muscarinic receptor agonists transiently activate phospholipase D in tracheal smooth muscle. Muscarinic activation of phospholipase D in this tissue is dependent on activation of protein kinase C and an unidentified pathway that is not protein kinase C dependent. Cholinergic agents have also been shown to activate phospholipase D by pathways linked to the small G protein, RhoA. This study explores the relationship between muscarinic activation of phophatidylinositol 3-kinase and activation of RhoA, and examines whether phospholipase D activation is dependent on either pathway in tracheal smooth muscle. Wortmannin or 2-(4-morphonyl)-8-phenyl-4H-1-benzopyran-4-one (LY-294002), putative specific inhibitors of phophatidylinositol 3-kinase, significantly inhibit acetylcholine-induced formation of phosphatidylethanol and also block acetylcholine-induced translocation of RhoA to the membrane. In previous experiments calphostin C, a protein kinase C inhibitor, partially inhibited both acetylcholine-induced and phorbol-12-myristate-13-acetate (PMA)-induced phosphatidylethanol formation. In the present study calphostin C did not block acetylcholine-induced RhoA translocation to the membrane. However, the Rho kinase inhibitor, N-(4-pyridyl)-4-(1-aminoethyl)-cyclohexanecarboxamide (Y-27632), significantly inhibited acetylcholine-induced phosphatidylethanol formation, but had no effect on activation of phospholipase D by PMA. Acetylcholine treatment also stimulated the phosphorylation of the 110-kDa subunit of phosphatidylinositol 3-kinase. Phosphorylation of phosphatidylinositol 3-kinase 110-kDa subunit could be blocked by wortmannin in a concentration-dependent manner, and acetylcholine-induced phosphatidylinositol 3-kinase activity was significantly inhibited by wortmannin. LY-294002 also inhibited acetylcholine-induced phosphorylation of 110-kDa subunit and activation of phosphatidylinositol 3-kinase. These results suggest that acetylcholine stimulation translocates RhoA to the membrane by a phosphatidylinositol 3-kinase-dependent mechanism and acetylcholine-induced phospholipase D stimulation is at least partly mediated via phosphatidylinositol 3-kinase, however, protein kinase C appears to activate phospholipase D independent of phosphatidylinositol 3-kinase or RhoA activation in porcine tracheal smooth muscle.

Weight control during the holidays: highly consistent self-monitoring as a potentially useful coping mechanism.

The study examined the extent to which trait self-monitoring (the systematic observation and recording of target behaviors) was related to weight control during the high-risk holiday season. The participants (32 women, 6 men) averaged 223.1 lbs (101.41 kg), 57.2% overweight, 50.2 weeks of participation, and 21.3 lbs (9.68 kg) lost at the beginning of the study. Consistency of self-monitoring and weight changes were assessed for 3 holiday versus 7 nonholiday weeks. Analyses of variance (Consistency of Self-Monitoring Groups x Holiday/Nonholiday Weeks) revealed that participants gained 500% more weight per week during holiday compared with nonholiday weeks. Only participants in the most consistent self-monitoring quartile averaged any weight loss over the 10 weeks of the study and during the holiday weeks.

How can obese weight controllers minimize weight gain during the high risk holiday season? By self-monitoring very consistently.

This study examined the efficacy of augmenting standard weekly cognitive-behavioral treatment for obesity with a self-monitoring intervention during the high risk holiday season. Fifty-seven participants in a long-term cognitive-behavioral treatment program were randomly assigned to self-monitoring intervention or comparison groups. During 2 holiday weeks (Christmas-New Years), the intervention group's treatment was supplemented with additional phone calls and daily mailings, all focused on self-monitoring. As hypothesized, the intervention group self-monitored more consistently and managed their weight better than the comparison group during the holidays. However, both groups struggled with weight management throughout the holidays. These findings support the critical role of self-monitoring in weight control and demonstrate the benefits of a low-cost intervention for assisting weight controllers during the holidays.

L-glutamate-induced changes in intracellular calcium oscillation frequency through non-classical glutamate receptor binding in cultured rat myocardial cells.

The effects of L-glutamate, N-methyl-D-aspartate (NMDA), kainate (KA) and L-alpha-amino-3-hydroxy-5-methyl-4-isoxazole proprionate (AMPA) on intracellular Ca2+ oscillation frequency were studied in cultured rat myocardial cells. Ca2+ oscillations per minute were increased as compared to control by L-glutamate (100 microM) from 3.8 +/- 2.2 to 25.7 +/- 4.3 (p < 0.001) and the NMDA-receptor agonist, NMDA (100 microM), from 1.2 +/- 0.8 to 34.8 +/- 10.1 (p < 0.011). Increases over control frequency were also seen in response to the non-NMDA receptor agonists KA (100 microM) from 5.8 +/- 2.3 to 25.6 +/- 3.2 (p < 0.001) and AMPA (10 microM) from 3.8 +/- 1.2 to 13.3 +/- 1.8 (p < 0.001). The non-competitive NMDA receptor antagonist, (+)-5-methyl-10,11-dihydro-5H-dibenzo[a,d]cyclohepten-5,10-imine maleate (MK801) (10 microM), decreased the Ca2+ oscillation frequency induced by NMDA (100 microM from 36.8 +/- 12.2 to 7.2 +/- 7.2 (p < 0.05). (+/-)-2-Amino-7-phosphonoheptanoic acid (AP7), a competitive inhibitor at the NMDA receptor inhibited the increase in frequency induced by KA (100 microM) at all concentrations tested (0.1, 1.0, 10 and 100 microM). 6,7-Dinitroquinoxaline-2,3-dione (DNQX), a competitive inhibitor at non-NMDA receptors, also decreased the oscillation frequency elicited by KA (100 microM) from 35.4 +/- 9.4 to 28.2 +/- 9.8, 24.8 +/- 9.8 and 11 +/- 9.5 at concentrations of 0.1, 1.0 and 10 microM respectively. The peak amount of intracellular Ca2+ as expressed as the fluo 3 ratio, F/Frcst, was not increased by L-glutamate, NMDA or KA. These results suggest the presence of a novel glutamate receptor composed of both non-NMDA and NMDA subunits on cultured rat myocardial cells, and receptor stimulation leads to an increase in intracellular Ca2+ oscillation frequency.

Effects of inhalation anesthetics of Kainate-induced glutamate release from cerebellar granule cells.

The mechanisms of inhalation anesthesia may include inhibiting non NMDA excitatory amino acid neurotransmission. This possibility was addressed by measuring the effect of three anesthetics at clinically relevant concentration on kainate-induced glutamate release from cerebellar granule cells. Cerebellar granule cells were obtained from 8-day-old SD rats and maintained in vitro for 9-14 days. Medium glutamate concentrations were measured by HPLC after 90 minutes incubation with kainate or NMDA. Inhalation anesthetics were introduced by holding the cells under a continuous flow of air/anesthetic mixtures. All anesthetics tested did not effect NMDA-induced glutamate release. Halothane (1 MAC), isoflurane (1 MAC) inhibited kainate-induced glutamate release from the cultured cells whereas enflurane (1 MAC) had no effect on kainate-induced glutamate release. The difference between enflurane and the other anesthetics tested suggests that anesthesia is dependent on more than one process and the extent at which each function is perturbed is dependent on the specific anesthetic used. Halothane inhibition of kainate-induced glutamate release was not reversible by increasing kainate concentration, indicating halothane does not directly compete with kainate at its receptor.

Ethanol-induced apoptosis in human HL-60 cells.

The mechanisms responsible for aberrant immune function associated with chronic ethanol use remain obscure, but a decrease in monocyte numbers is often reported for individuals who chronically abuse ethanol. We investigated, using human HL-60 promyelocytic cell line, the possibility that ethanol induces apoptosis which contributes to decreased monocyte numbers. Characteristic features of apoptosis were observed 4 days after ethanol treatment, as documented by increased DNA fragmentation; enhanced expression of phosphatidylserine, an early marker of apoptosis; and the appearance of a hypodiploid apoptotic cell population identified by flow cytometry analysis of the cell cycle. Treatment with the protein kinase C inhibitor, GF 109203X, potentiated ethanol-induced apoptosis. Direct induction of human HL-60 cell apoptosis by ethanol and potentiation of ethanol-induced apoptosis by inhibiting protein kinase C provides a partial explanation for the cytotoxic effects of ethanol on hematopoietic progenitor cells and establishes a link between inhibiting protein kinase C activity and ethanol-induced apoptosis.

A comparison of fresh and frozen poultry.

Chicken broilers, chicken roasters, turkeys, and ducks were split; then one half was stored frozen; the other half was iced. Two days later, both halves were baked and then evaluated using the triangle test. Shear values and expressible fluid values were also determined. The taste panel could not significantly distinguish between fresh and frozen thawed paired halves of roast poultry. Objective testing by shearing and expressible moisture losses also failed to show a significant difference. However, of the judges who could distinguish between the fresh and the frozen thawed samples, the greater percentage preferred the fresh samples.