Conformations of peptides corresponding to fatty acylation sites in proteins. A circular dichroism study

Fatty acid acylation is a posttranslational modification found in membrane proteins that have hydrophobic sequences serving as transmembrane segments as well as those that do not have them. The fatty acids myristate and palmitate are linked through an amide bond to N-terminal glycine and SH of cysteine via a thioester bond, respectively. In order to elucidate whether or how fatty acid acylation would modulate peptide structure, especially in hydrophobic environment, we have carried out circular dichroism studies on synthetic peptides both hydrophobic and hydrophilic in nature, corresponding to fatty acylation sites and their fatty acyl derivatives. The hydrophilic peptides were approximately 12 residues in length as studies on proteins modified by site-directed mutagenesis indicated that a peptide segment of approximately 12 residues is sufficient to direct acylation as well as membrane association, especially when the fatty acid is myristic acid. The peptide corresponding to a transmembrane segment composed of 31 residues as well as its palmitoyl derivative was found to adopt alpha-helical structure. Acylation appeared to favor increased partitioning into miscelles even in the case of a hydrophobic peptide. The hydrophilic peptides and their myristoyl or palmitoyl derivatives showed very little ordered structure in micelles. Our results suggest that the myristoyl and the palmitoyl moieties do not have the ability to "force" a hydrophilic peptide segment into a hydrophobic micellar environment. Thus, the mere presence of a fatty acid moiety may not be sufficient for membrane binding and recycling as is assumed especially in proteins in which no hydrophobic segment is present.

Interaction of peptides corresponding to fatty acylation sites in proteins with model membranes

In recent years, a large number of proteins having covalently linked myristic and palmitic acids have been discovered. It is assumed that fatty acid acylation serves to anchor proteins to membranes. However, it is not clear whether fatty acids modulate orientation of peptide chain in membranes or help in associating hydrophilic segments of peptides with membranes. We have examined the aggregation properties and membrane association of peptides corresponding to myristoylation and palmitoylation regions of proteins by fluorescence spectroscopy. Both acylated and non-acylated peptides were used for investigation. Binding of the peptides to lipid vesicles was assessed by monitoring the fluorescence of tryptophan as well as the quenching of its fluorescence in the presence of quenchers like I- and acrylamide. Our results indicate that in the peptide corresponding to a transmembrane segment, palmitoylation results in a change in the orientation of the peptide chain in the lipid bilayer. In the case of peptides that do not have a hydrophobic segment, acylation with palmitic or myristic acid does not appear to result in increased binding to lipid bilayer. Our results suggest that (i) the primary role of myristoylation may not be an anchor for membrane attachment as assumed, (ii) palmitoylation in the case of proteins having transmembrane segments may serve to realign the transmembrane segment from the normal orientation perpendicular to the bilayer surface, (iii) in the case of proteins where there is no hydrophobic segment, palmitoylation may not serve as a membrane anchor and could be involved in interaction with other membrane-bound proteins.

Allergen-stimulated T lymphocytes from allergic patients induce vascular cell adhesion molecule-1 (VCAM-1) expression and IL-6 production by endothelial cells

Adhesion of inflammatory cells to endothelium is a critical step for their transvascular migration to inflammatory sites. To evaluate the relationship between T lymphocytes (TL) and vascular endothelium, supernatants from allergen-stimulated TL obtained from patients sensitive to Dermatophagoides pteronyssinus (Dpt) versus healthy subjects were added to endothelial cell (EC) cultures. TL were stimulated by autologous-activated antigen-presenting cells (APC) previously fixed in paraformaldehyde to prevent monokine secretion. Two parameters were measured: the expression of adhesion molecule and the production of IL-6. Related allergen-stimulated TL supernatants from allergic patients induced an increase of VCAM-1 and intercellular adhesion molecule-1 (ICAM-1) expression when supernatants of the control groups (TL exposed to an unrelated allergen or not stimulated or TL obtained from healthy subjects) did not. E-selectin expression was not modulated whatever the supernatant added to EC culture. IL-6 production by EC was significantly enhanced after activation with related allergen-stimulated TL supernatants from allergics compared with control supernatants. Induction of VCAM-1 expression was inhibited by adding neutralizing antibodies against IL-4, whereas IL-6 production and ICAM-1 expression were inhibited by anti-interferon-gamma (IFN-gamma) antibodies. Enhanced production of IL-4 and IFN-gamma was detected in related allergen-stimulated TL supernatants from allergic subjects compared with the different supernatants. These data suggest that allergen-specific TL present in the peripheral blood of allergic patients are of Th1 and Th2 subtypes. Their stimulation in allergic patients may lead to the activation of endothelial cells and thereby participate in leucocyte recruitment towards the inflammatory site.

Implications of gynaecological abnormalities in pre-selection criteria for cervical screening: preliminary evaluation of 3602 subjects in south India

Early detection and eradication of cervical cancer and its precursor lesions through organized mass cytological screening programmes have recently gained considerable attention in developing countries. Strategies for both cost saving and effective implementation are however required for mass cervical screening in developing countries. In an early cancer detection programme conducted in South India, we analysed cytological abnormalities in 3602 women and correlated the results with other factors, including age, gynaecological complaints, number of years of married life and parity to see if pre-selection for cytologic screening was possible. Only lower grades of dysplasia were found in asymptomatic women below the age of 40 years. In asymptomatic women, malignancy and higher grades of dysplasia were confined to women with a clinically abnormal cervix only. Univariate analysis also revealed that subjects with a parity of more than 3 and a married life of more than 20 years had a significantly higher number of cytological abnormalities. However, on a multivariate analysis the increased number of marital years was not found to be an independent variable. These results suggest that asymptomatic women below the age of 40 years with a married life of less than 20 years and parity below 3, may be excluded from screening campaigns, and that pre-selection for cytologic screening is possible by introducing a programme of clinical and speculum examination of the cervix.

Ureteric ischaemia following major colorectal resection

An ischaemic injury of the ureter following major colorectal surgery is reported. The aetiology and incidence of this unusual complication is reviewed. Surgical techniques for prevention of such an injury are discussed.

A modified transfacial approach to the clivus

Anterior approaches to the clivus must provide excellent visualization of the lesion, give adequate access for dural repair, and be cosmetically acceptable. Most current approaches enter through the nasopharynx or oropharynx, with either palatal, maxillary, or mandibular splitting for greater exposure. We have modified the transfacial approach described by others, which provides excellent access to the clivus along its rostrocaudal extent. A lateral rhinotomy incision is used and carried along the base of the right alae nasi and columella. The nasal bones are osteotomized bilaterally, and the nose is rotated on a pedicle flap, thus opening the entire nasal cavity to view. The septum and medial maxillary walls are removed. This provides excellent visualization of the ethmoid, sphenoid, posterior nasopharynx, and upper oropharynx. At the conclusion of the procedure, the nasal incision is closed, with good cosmesis. A case of recurrent chordoma of the middle and lower clivus is presented to exemplify this technique. The approach has since been used to approach clivus tumors and midline aneurysms of the vertebrobasilar system.

Histamine induces IL-6 production by human endothelial cells

Histamine is one of the major mediators implicated in the physiopathology of allergy. On vascular endothelium, histamine mainly induces early effects: an increase in vasopermeability leading to oedema, a release of lipid mediators and a transient expression of P-selectin. The aim of this study was to evaluate the effects of histamine on adhesion molecule expression and IL-6 production by human endothelial cells. Histamine did not modulate the expression of intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1) and E-selectin, but induced a transient expression of P-selectin as previously reported. In addition, histamine increased in a dose- (from 10(-5) to 10(-3) M) and time- (from 4 h to 24 h) dependent fashion the IL-6 synthesis by endothelial cells. Tumour necrosis factor-alpha (TNF-alpha)-induced IL-6 production was also potentiated in a dose-dependent manner by histamine, without modification of the time course of IL-6 secretion. Moreover, this increase of IL-6 production induced by histamine was inhibited in a dose-dependent manner by H1 and H2 histamine receptor antagonists (50% inhibition of IL-6 production at 5 x 10(-4) M and 4 x 10(-5) M, respectively). So, histamine induces, besides already well known effects, a late stimulation of endothelial cells, i.e. the production of IL-6.

Baseline body temperatures of patients with myelopathy

In myelopathy patients, baseline body temperatures and effects of common ambient temperatures have not been measured. Oral (OT), rectal (ReT) and room (RmT) temperatures were measured between 5 and 7 A.M. in 46 myelopathy patients (one female) aged 61 +/- 14 (mean +/- 1 standard deviation) who had been paralyzed 20 +/- 12 years. Their levels of paralysis were cervical in 34, dorsal in 11, lumbar in one. OT was 36.2 (97.1 degrees F) +/- 0.6 degrees C and RT 36.7 (98.0 degrees F) +/- 0.6 degrees C, correlation coefficient (r) = 0.723. RmT was 23.9 +/- 1.9 degrees C (75.1 +/- 3.4 degrees F), but RmT did not correlate with ReT, r = 0.088, in spite of a 19 degrees F difference between the extremes of RmT. In conclusion, the early morning body temperature of myelopathy subjects is lower than the generally recognized norm but is unaffected by a moderately wide range of ambient temperatures in a hospital setting.

Modulation of endothelial cell adhesion molecule expression in a situation of chronic inflammatory stimulation

Different disorders affecting the respiratory tract are characterized by the development of a chronic inflammatory reaction with an accumulation of immune and inflammatory cells into the bronchial walls and in interstitial and alveolar spaces. By its ability to secrete a large panel of cytokines, in particular TNF-alpha, the alveolar macrophage (AM) is undoubtedly playing a key role in the complex interactions between inflammatory and structural cells potentially implicated in the inflammatory reaction of the lung. One aspect of these interactions is the capacity of AM-derived TNF-alpha to induce the expression of cellular adhesion molecules (CAM) on the surface of endothelial cells. The main information concerning the induction of CAM have been obtained under experimental conditions mimicking an acute inflammatory reaction. In the present study, we propose an in vitro model allowing the reproduction of the conditions of a chronic inflammation, namely, the endothelial cell behavior submitted to a chronic TNF-alpha stimulation. The endothelial cell activation parameters were the modulation of expression of adhesion molecules: endothelial-leukocyte adhesion molecule-1 (E-selectin), intercellular adhesion molecule-1 (ICAM-1), and vascular adhesion molecule-1 (VCAM-1). Their functional abilities was evaluated using U937 cell adhesion analysis. Results demonstrated an overexpression of ICAM-1 after chronic stimulation performed with low but repeated doses of TNF-alpha. The level of ICAM-1 expression persisted throughout the culture to reach a high stable level despite the absence of detectable TNF-alpha activity in culture supernatants. If the stimulation was stopped after 6 days, the expression of ICAM-1 was still observed at least until Day 15. E-selectin and VCAM-1 expression remained absent or not significantly increased. The expression of ICAM-1 on endothelial cells was directly related to an enhanced adhesion capacity as demonstrated by the adhesion of U937 cells to endothelial cells by an ICAM-1/LFA-1 adhesion pathway. Taken together, these elements could bring new approaches in the investigation of mechanisms by which inflammatory cells are recruited and participate in chronic inflammatory processes.

Tumor necrosis factor-alpha release during systemic reaction in cold urticaria

Primary cold urticaria (PCU) characterized by the association of urticaria, angioedema, and sometimes a shock-like reaction after cold exposure, is usually considered to be linked with histamine and prostaglandin D2 release by mast cells. To determine the involvement of cytokines, we studied the release of tumor necrosis factor-alpha (TNF-alpha) in the blood of the efferent vein after immersion of the hand in chilled water. Five patients with PCU were compared with a control population (three patients with nonphysical urticaria and three healthy subjects). Among patients with PCU who underwent the cold immersion test, two exhibited a shock-like reaction with a large urticarial plaque (patients 1 and 2), one had only a mild cutaneous reaction, and two had no reaction. Patient 1 was reevaluated after 6 months of treatment with H1 and H2 antihistamines: he did not respond to this challenge. All controls were strictly negative. Histamine was released within the first minute after the challenge in the three patients with PCU, but at a higher level for the two patients who had a systemic reaction. TNF-alpha was undetectable in the blood of the patient with only a mild cutaneous reaction, whereas TNF-alpha release was observed for the two patients with a systemic reaction, 2 and 6 minutes after the end of the cold immersion test. The two other patients and the control subjects released neither histamine nor TNF-alpha. In parallel, pathologic and immunohistochemical (with a rabbit anti-TNF-alpha antibody) studies were performed on skin biopsy specimens collected 10 minutes after ice-cube test.(ABSTRACT TRUNCATED AT 250 WORDS)

Interleukin-6 and interleukin-1 alpha production is associated with antigen-induced late nasal response

BACKGROUND

Cytokines such as tumor necrosis factor (TNF)-alpha, interleukin (IL)-1 alpha, IL-6 and granulocyte macrophage-colony stimulating factor (GM-CSF) are able to potentiate allergic inflammation and seem to be implicated in the development of the late allergic reaction.

METHODS

To study the time course of cytokine production, sequential lavages were performed after nasal allergen challenge. Thirteen patients with allergic rhinitis and four healthy subjects were exposed to grass pollen (n = 6 and n = 2, respectively) or dust mite allergen (n = 7 and n = 2, respectively).

RESULTS

Among the patients with allergic rhinitis, a single early response (single responders) developed in four, eight exhibited a dual response (dual responders) and one patient as well as the four healthy subjects did not respond. In addition to the measurement of IL-1 alpha, IL-6, TNF-alpha and GM-CSF concentrations by ELISA, the release of histamine, tryptase, and eosinophil cationic protein was also evaluated by radioimmunoassay performed on nasal lavage fluids. Concerning mediator levels in nasal lavage fluid, neither histamine release nor cytokine elevation were noted in healthy subjects. As previously described, histamine, tryptase and eosinophil cationic protein were released in single and dual responders. Concerning cytokines, TNF-alpha was undetectable in the majority of nasal lavages and an increase in GM-CSF concentration was occasionally observed whatever the type of response. In contrast, an increase in IL-1 alpha and IL-6 levels was observed for dual responders during the early period (12.6 +/- 3 and 9.2 +/- 2 pg/ml, respectively; p < 0.01 in both cases) and at a higher level during the late period (14.5 +/- 4, p not significant and 16.7 +/- 8 pg/ml, respectively; p < 0.01) when compared with baseline values (7.2 +/- 2.2 and 2 +/- 0.7 pg/ml, respectively). For single responders IL-1 alpha and IL-6 secretion was detected mainly during the early period.

CONCLUSION

These data suggest a role for IL-1 alpha in the induction and perennisation of the inflammatory reaction in allergic rhinitis, whereas the role of IL-6 remains to be investigated.

Modulation of adhesion molecule expression on endothelial cells during the late asthmatic reaction: role of macrophage-derived tumour necrosis factor-alpha

In a previous work we have demonstrated that in patients exhibiting a late allergic reaction (LAR), alveolar macrophages (AM) collected 18 h after bronchial allergen challenge produced high levels of IL-6 and tumour necrosis factor-alpha (TNF) which is known to up-regulate the endothelial cell expression of adhesion molecules participating in the development of the inflammatory reaction in bronchial asthma. For these reasons, we evaluated the effect of AM supernatants from asthmatic patients developing an LAR on intercellular adhesion molecule-1 (ICAM-1) and endothelial leucocyte adhesion molecule-1 (ELAM-1) expression by human endothelial cells. The expression of adhesion molecules was assessed by an ELISA method and compared with the effect of an optimal dose of human recombinant (hr) TNF. Results showed that AM supernatants, from challenged asthmatics developing an LAR, increased significantly the ICAM-1 and ELAM-1 expression on endothelial cells to a level similar to that obtained in the presence of hrTNF (500 U/ml) (P < 0.001 in both cases, respectively 90.4% and 75.2% of the level obtained with hrTNF). In contrast, AM supernatants from asthmatics at baseline or exhibiting, after challenge, a single early reaction had no significant effect on these parameters (P = NS in both cases, respectively 23.5% and 24.7% of the ICAM-1 expression, 22.7% and 15.3% of the ELAM-1 expression obtained with hrTNF). AM-derived TNF present in these supernatants was thought to play a key role in endothelial cell stimulation, since: (i) TNF concentration in AM supernatants correlated with its effect on ICAM-1 (r = 0.80, P < 10(-4)) and ELAM-1 expression (r = 0.88, P < 10(-5)); and (ii) a neutralizing anti-TNF antibody decreased their effect (68% and 80% respectively on ICAM-1 and ELAM-1 expression). Moreover, the role of IL-6 was excluded on the basis both of the hrIL-6 inefficiency to induce ICAM-1 and ELAM-1 synthesis, even in costimulation with hrTNF, and of anti-IL-6 antibody to neutralize the effect of AM supernatants. Our results suggest that, beside mast cells and lymphocytes, macrophages might participate in the induction of the local inflammatory reaction observed in bronchial asthma. During the LAR, cytokines and especially TNF are able, through an enhanced adhesion molecule expression on endothelial cells, to facilitate the bronchial cellular influx.

Comparison of community based service with hospital based service for people with acute, severe psychiatric illness

OBJECTIVE

To compare the burden on relatives and outcome of people treated for severe acute psychiatric illness by a community service and a traditional hospital based service.

DESIGN

Follow up of patients aged 16-65 who required admission to hospital or home treatment for psychiatric illness during January 1990 to February 1991.

SETTING

Two Birmingham electoral wards, Sparkbrook and Small Heath; Sparkbrook has a community based service and Small Heath a traditional hospital based service.

SUBJECTS

69 patients from Sparkbrook and 55 from Small Health.

MAIN OUTCOME MEASURES

Scores on present state examination, social behaviour assessment schedule, and general health questionnaire.

RESULTS

24 (35%) of Sparkbrook patients received some treatment in hospital during the initial episodes. Relatives of Sparkbrook patients were less distressed by their burden at the initial assessment than relatives of Small Health patients (mean score 0.11 v 0.29, p < 0.01). Relatives were also more satisfied with the support they received and the treatment received by patients. More patients from Sparkbrook than Small Health were in contact with a psychiatrist (81% (95% confidence interval 71% to 91%) v 62% (44% to 68%)) and community nurse (56% (44% to 68%) v 14% (13% to 24%)) one year after the initial episode. Sparkbrook patients spent significantly fewer days in hospital during the initial episode (8 days v 59 days) and the first year (20.6 v 67.9 days).

CONCLUSION

The community based service is as effective as the hospital based service and is preferred by relatives. It is more effective in keeping people in long term contact with psychiatrists.

Biosynthesis of gamma-linolenic acid in developing seeds of borage (Borago officinalis L.)

delta 6-desaturation of [14C]linoleoyl-CoA or [14C]oleoyl-CoA leading to the synthesis of gamma-linolenic acid was studied in vitro with microsomal fractions from developing seeds of Borago officinalis. Time course of the reaction, effects of protein and precursor concentrations and nucleotide requirements were examined. These parameters allowed us to improve the in vitro delta 6-desaturation assay. We observed that the precursors were acylated mainly in phosphatidylcholine, diacylglycerol and triacylglycerol, and then desaturated. NADH was absolutely required when [14C]oleoyl-CoA was the precursor, but not when [14C]linoleoyl-CoA was the precursor although it stimulated the reaction. The in vitro delta 6-desaturase activity was found mainly in phosphatidylcholine, associated with enriched endoplasmic reticulum membranes (ER) from embryos. No activity was observed in ER from seed coat or seedling. During maturation of the seeds, delta 6-desaturase reached its highest activity 14 to 16 days after pollination.

Production of anti-endothelial cell antibodies by coculture of EBV-infected human B cells with endothelial cells

Vascular endothelial cells are suspected of being the target of autoimmune processes seen in many connective tissue diseases and in systemic vasculitis as evidenced by the detection of circulating autoantibodies against endothelial cell antigens. In order to select B cells recognizing endothelial cells antigens, Epstein-Barr virus (EBV)-infected B cells, obtained from one patient presenting a systemic vasculitis, were cocultured with human endothelial cells concurrently with a human endothelial cell line (EC-pSV1 cells). This coculture consisted of a first step of expansion of B cells specifically selected by adherence onto human umbilical vein endothelial cells (HUVEC). The adherence of selected B cells was specific to endothelial cells because no rosette formation around control cells (HeLa cells or COS cells) was observed. Adherent B cells were cloned by limiting dilution by coculture onto EC-pSV1 cells and screened for anti-HUVEC antibody production by endothelial cell ELISA. An increase in anti-HUVEC antibody production of IgM isotype was detected by endothelial cell ELISA, peaking at Day 9 and remaining constantly elevated, relative to B cell expansion. Among 21 B cell lines producing IgM, 6 presented high levels of anti-HUVEC antibodies, whereas 1 of 52 B cells cloned without EC-pSV1 cells showed such antibody production. Anti-HUVEC antibody production and B cell proliferation were dependent on the presence of endothelial cells. Two of these 6 B cell lines produced antibodies directed against an endothelial cell antigen with an apparent molecular weight of 192 kDa as determined by immunoblotting analysis. Our results demonstrate that adherence of EBV-infected B cells to endothelial cells and further cloning by adherence can efficiently select anti-HUVEC antibody-producing human B cells and might help to define antigens potentially involved in autoimmune diseases.

Modulation by nedocromil sodium of immunologic and nonimmunologic activation of monocytes, macrophages, and platelets

Human monocytes, alveolar macrophages, and blood platelets were used in vitro to investigate the effects of nedocromil sodium on their IgE-dependent stimulation. The drug induced a significant inhibition of the IgE-mediated generation of cytotoxic mediators in both cell populations. This was evidenced by a strong inhibition of the killing of schistosome larvae and decreased free radical production, as demonstrated by chemiluminescence. Nedocromil sodium also produced a significant inhibition of lysosomal enzyme release and synthesis in alveolar macrophages. These effects reached a maximum between 10(-9) and 10(-7) mol/L nedocromil sodium. The 50% inhibition concentration was 10 times lower. The drug was also tested on IgE-activated rat peritoneal macrophages and blood platelets with similar results. Finally, nedocromil sodium was shown to inhibit the abnormal response to aspirin of platelets, both in vitro and ex vivo, from aspirin-sensitive asthma patients.

Synthesis and structure-activity relationships of new cephalosporins with aminoimidazoles at C-7. Effect of the pKa of the C-7 aminoimidazole on antibacterial spectrum and beta-lactamase stability

Cephalosporins with new aminoimidazole heterocycles at C-7 have been synthesized by reaction of anti-alpha-aminooximes with C-7 dihaloisocyanocephalosporins esters or by direct condensation of 2-fluoroimidazoles with C-7 aminocephalosporins esters. These compounds combine a broad spectrum of antibacterial activity, including Gram-negative and Gram-positive organisms with a good beta-lactamase stability. Activity is discussed in terms of its relationship to the pKa of the C-7 aminoimidazole heterocycle, basic C-7 aminoimidazole residues gave cephalosporins with the best beta-lactamase stability but the poorest activity against Gram-positive organisms. An additional interesting property of the C-7 imidazolylaminocephalosporins is the oral activity present in some compounds of this series.

Lung function and surfactant distribution in saline-lavaged sheep given instilled vs. nebulized surfactant

Adult sheep (35 +/- 3 kg) underwent saline lung lavage and 1.5 h of mechanical ventilation to induce acute lung injury. Animals received 100 mg lipid/kg body wt of tracheally instilled surfactant (Inst Surf) or either nebulized surfactant (Neb Surf) or nebulized saline (Neb Saline) and were killed 3 h later. Inst Surf and Neb Surf groups had significant improvements in oxygenation (P < 0.01) and peak inspiratory pressures (PIP) (P < 0.05) compared with pretreatment values. Improvements in oxygenation and PIP for Inst Surf animals were significantly greater than for Neb Surf animals (P < 0.05). Volumes of maximal pressure of quasi-static pressure-volume curves measured at the time the animals were killed were significantly greater for Inst Surf and Neb Surf animals than for animals given Neb Saline (P < 0.05). Alveolar recovery of exogenous surfactant was 100 times greater for Inst Surf animals (1,732 +/- 70 mg) than for Neb Surf animals (15.3 +/- 2.9 mg) at the time they were killed. Although there were no differences in exogenous surfactant distribution patterns at the lobar level between the two surfactant-treated groups, distribution histograms calculated for 10-g lung pieces revealed the Neb Surf animals had significantly more pieces within 25% of the mean value of 1.0 (42.7 +/- 6.9%) than did Inst Surf animals (20.8 +/- 5.5%) (P < 0.01). Exogenous surfactant therapy improved lung function with significantly different quantities of surfactant deposited in lung tissue for the two delivery methods evaluated.

A colorimetric assay to evaluate the immune reactivity of blood platelets based on the reduction of a tetrazolium salt

Since the first report in 1983, blood platelet reactivity from patients with immediate hypersensitivity reactions, and particularly allergic asthma and aspirin-sensitive asthma, has been evaluated by the release of cytotoxic mediators able to induce the death of parasite larvae, and by the generation of oxygen derived free radicals, measurable by chemiluminescence. We demonstrate here that platelets are able to reduce MTT tetrazolium salt proportionally to the stimulation level in two models of platelet triggering, one IgE-dependent and one aspirin-dependent. This method correlated significantly with the cytotoxicity assay of platelet stimulation (r = 0.965, p < 10(-5) for IgE-dependent stimulation; r = 0.723, p < 10(-4) for aspirin-dependent stimulation). The MTT colorimetric assay should complement or possibly replace previous methods of assessing platelet activation which were of limited use allowing broader investigations on the involvement of platelets in immune processes and in allergic or pseudoallergic reactions.

An international comparison of case definition of severe adverse cutaneous reactions to medicines

There is substantial intercountry variation in the proportion of cases of toxic epidermal necrolysis (TEN) and Stevens-Johnson syndrome (SJS) which are attributed to specific drugs. This study was undertaken to determine whether these differences might reflect biases in diagnosis of these conditions. A total of 138 reactions in 5 countries originally diagnosed as TEN or SJS were coded on to standardised forms. A single observer blind to the original diagnosis assessed each case according to specified criteria. This observer's diagnoses were compared with the original diagnoses. Overall, 111 of the 138 cases had information adequate for assessment. The blinded observer agreed with the diagnosis for 61% of cases where the original diagnosis was TEN and 58% of cases where the original diagnosis was SJS. There was no significant difference in rates of agreement when reactions attributed to sulphonamide antibiotics were compared with reactions attributed to other drugs. There were substantial and significant differences in percentage agreement between the blinded observer's diagnosis and the original diagnoses between countries. The lowest rates of agreement between the blinded observer and the original reports occurred in the US. Our results illustrate the difficulty in comparing reaction rates based on spontaneous reports between countries where the systems for gathering such reports vary. This illustrates the need for a minimum quantity of standard data and precise definitions of reactions if spontaneous reports of adverse reactions are to provide useful information about severe adverse skin reactions associated with drugs.

Acute psychosis diagnosed as schizophrenia in icd 9 : a discriminant validity study

Consequent to the ICD-10, schizophrenic patients with illness duration of less than one month will now be diagnosed as acute and transient psychosis. On the basis of the hospital records of 891 first admission patients, the acute schizophrenic patients (n=253) were compared on demographic and clinical characteristics with the rest of the patients (n = 548) under 295 of the ICD-9 diagnosis. Logistic discriminant function analysis on 21 variables achieved 88% overall correct classification rate, 86% for short duration group and 89% for long duration group. Vie significance of the results is discussed.

Tumor necrosis factor alpha and interleukin-6 production by human mononuclear phagocytes from allergic asthmatics after IgE-dependent stimulation

We have previously demonstrated the production of tumor necrosis factor alpha (TNF) and interleukin-6 (IL-6) by alveolar macrophages (AM) from allergic asthmatics developing a late asthmatic reaction after bronchial allergen challenge. In order to explain the modalities of this monokine synthesis, we tested in vitro the effect of an IgE-dependent stimulation on blood monocytes (BM) and AM from control and asthmatic subjects. TNF and IL-6 secretions were evaluated in 24-h supernatants by radioimmunoassay and by the 7TD1 cell proliferation test, respectively. AM from allergic asthmatics secreted spontaneously higher concentrations of TNF and IL-6 than did BM or AM from control subjects. BM from asthmatics also produced spontaneously increased levels of TNF, but at a lesser degree than did AM. The addition of anti-IgE induced a significant increase of TNF and IL-6 secretions by mononuclear phagocytes from control subjects only after previous sensitization with IgE-rich medium. In contrast, the direct stimulation by allergen or anti-IgE of AM and BM from asthmatics enhanced significantly the production of TNF and IL-6 when compared with cells cultured in medium alone. In these conditions, IgE-dependent activation of cells from allergic asthmatics compared with those from control subjects increased monokine production in a similar manner. Costimulation by recombinant human interferon gamma and IgE-dependent triggering had a synergistic effect on TNF production, but it had only an additive action on IL-6 synthesis (respective increase index: 9.8 compared with 2.9 and 9.8 compared with 2.1, respectively, for BM from control and asthmatic subjects).(ABSTRACT TRUNCATED AT 250 WORDS)

Clinical and laboratory correlates of human immunodeficiency virus infection in a cohort of intravenous drug users from New York, NY

BACKGROUND

The human immunodeficiency virus (HIV) epidemic has increasingly involved intravenous drug users. Few studies have attempted to define its clinical and laboratory characteristics in this population.

METHODS

We recruited 223 intravenous drug users from New York, NY, for a prospective study of the natural course of HIV infection. Medical history, physical examination, medical staging, and immunologic assessments were performed at 6-month intervals. We examined the baseline findings among this cohort.

RESULTS

Of the total cohort, 65.9% were men and 34.1% were women, with 70.9% African American, 12.6% white, 11.7% white Latino, and 4.9% black Latino. At baseline, 44.4% were HIV negative and 55.6% were HIV positive. No significant association was noted between ethnicity, gender, and serologic status. Also no significant difference was noted for homelessness either across serologic status or gender. There was a trend toward an association between gender and use of drugs during the week before interview; the women showed higher drug use. A significant association was noted between HIV serologic status and reported history of pneumonia, oral candidiasis, cough, night sweats, fever, and lymphadenopathy on physical examination. In a regression model, white blood cell count, hematocrit, symptom/sign complex score, and CD4 cell number were significantly associated with HIV status.

CONCLUSION

This study provided important historical, clinical, and immunologic characteristics that are useful in the identification and evaluation of the HIV-infected intravenous drug user.

Specific histamine release capacity of peptides selected from the modelized Der p I protein, a major allergen of Dermatophagoides pteronyssinus

Dust mite allergens are considered as a major cause of allergic disease and as a risk factor for asthma. Der p I, a 222 amino-acid residue globular glycoprotein, is one of the major allergens from Dermatophagoides pteronyssinus (Dpt) mites. In this study, we have used predictive conventional algorithms (i.e. hydrophilicity, mobility, accessibility) and a three-dimensional model of Der p I derived from comparison to actinidin and papain to select continuous amino acid sequences as potential B cell epitopes. Four peptides, 52-71, 117-133, 176-187, 188-199 were synthesized. Their antigenic reactivity was investigated, mainly by measuring their capacity to induce in vitro histamine release. Results indicated that only Dpt-sensitive patients react specifically to Der p I-derived peptides and more frequently to 52-71 and 117-133. For each peptide, the intensity of response was dependent on the patient tested and on the peptide concn. The capacity of peptides to induce histamine release was demonstrated to be correlated with the serum level of anti-Der p I IgE (r = 0.86; p less than 10(-2)). Taken together these data emphasize, in Dpt-sensitive patients, the heterogeneity of the specific response to synthetic Der p I-derived peptides and underline the possible variety of epitopes belonging to the allergen Der p I.

Separate induction of human blood platelet aggregation or cytotoxicity by different concentrations of PAF-acether and thrombin

Using decreasing concentrations of PAF-acether or thrombin, it was possible to observe on human platelets, first, aggregation, classically associated to activation, then , below a threshold, cytotoxicity towards Schistosoma mansoni larvae, proposed here as stimulation. These two activities appeared as distinct and antithetic. However, their induction might be the consequence of triggering of the same receptors with different intensity, since PAF-induced, but not thrombin-induced, cytotoxicity could be inhibited with specific PAF-antagonists BN 52021 and BN 52024 also known to inhibit PAF-induced aggregation. These results give credit to the hypothesis that haemostatic and cytotoxic properties of platelets are two distinct functions of these blood elements.

Unfolding of lysozyme by breaking its disulphide bridges results in exposure of hydrophobic sites

The interaction of 1-anilino-naphthalene-8-sulphonate (ANS), a probe whose fluorescence is strongly dependent on hydrophobicity of the environment, with native lysozyme and lysozyme partially unfolded by breaking the disulphide bridges and reacting the free -SH groups with iodoacetamide, has been investigated. Monitoring the intensity of ANS fluorescence and the position of the emission maximum in the presence of native and partially unfolded lysozyme indicated that unfolding resulted in the exposure of hydrophobic sites. Hydrophobic sites could not be detected when native and partially unfolded lysozyme were denatured with urea or guanidinium chloride. Protein components of the cells export machinery like 'chaperones' associate only with partially unfolded proteins and not native, folded proteins. Hence, hydrophobic regions of proteins, exposed on partial unfolding, could be the sites of recognition by 'chaperone' proteins.

Levels of soluble IL-2 receptor in plasma from asthmatics. Correlations with blood eosinophilia, lung function, and corticosteroid therapy

Evidence now suggests that eosinophils and T lymphocytes infiltrating bronchial tissues may play a key role in the pathophysiology of asthma. Circulating eosinophils, lung function, and plasma soluble IL-2 receptor (sIL-2R) were measured in 42 asthmatic patients referred for symptomatic asthma. The patients were divided into two groups based on the presence or absence of atopy. The group of non-atopic asthmatics was further divided according to the patients' requirement for long term oral corticosteroids. The mean sIL-2R +/- s.d. was 36.3 +/- 9.9 pM in the control group, 28.9 +/- 9.2 pM in the atopic asthmatics, 43.3 +/- 18.07 pM in the non-atopic asthmatics without oral steroid therapy, but was increased in the steroid-treated group (62.2 +/- 19.3 pM, P less than 0.01). A significant correlation was found between FEV1 and circulating eosinophils in atopic asthmatics and in non-atopic asthmatics without oral corticosteroid therapy, but not in the steroid-treated group. Furthermore, significant correlations were found between sIL-2R and FEV1, and between sIL-2R and blood eosinophils, in the group of non-atopic asthmatics not on oral steroid therapy. No such correlations were evidenced in the other groups of asthmatics. Similar results were obtained during the clinical course of three non-atopic patients followed for more than 1 year. These data suggest that T cell activation appears more prominent in non-atopic asthma than in atopic asthma. Moreover, it appears that T cell activation can occur in severe forms of asthma despite steroid treatment. Finally, the results suggest a possible link between T cell activation, eosinophils, and lung function, which may reflect a particular pathogenetic mechanism involved in non-atopic asthma.

Specific activation of platelets from patients allergic to Dermatophagoides pteronyssinus by synthetic peptides derived from the allergen Der p I

Previous studies have shown that Fc epsilon RII-bearing platelets from patients with allergic disorders could be stimulated either by anti-human IgE antibodies or the relevant allergens to generate cytotoxic mediators. In this report, the reactivity of platelets from Dermatophagoides pteronyssinus (D. pt)-sensitive patients to three Der p I-derived synthetic peptides (52-71, 117-133 and 188-199) was investigated. The platelet stimulation observed in D. pt-sensitive patients was demonstrated to be allergen-specific and to be mediated by IgE. These Der p I-derived peptides failed to stimulate platelets from healthy donors or platelets from non-D. pt-allergic patients. D. pt-sensitive patients responded more frequently to the peptides 52-71 and 117-133 than to the peptide 188-199. Thus, in this model, synthetic peptides selected for their assumed accessibility on the native antigen could be associated to an IgE-dependent biological activity.

Botulinum a toxin for spasmodic torticollis: multiple vs single injection points per muscle

Eighty-six injections in 49 patients with adult onset spasmodic torticollis were evaluated for efficacy with respect to single point per muscle versus multiple point per muscle injection techniques. Parameters of the syndrome assessed were pain, posture deformity, range of cervical motion, disfigurement, cervical muscle hypertrophy, activity limitation, and degree of involuntary movement. The multiple point per muscle injection strategy appeared superior to the single injection per muscle technique with respect to pain (p less than 0.002, chi-square), posture deformity (p less than 0.001), range of motion (p less than 0.001), and improvement in activity endurance (p less than 0.001). No significant differences were noted with respect to cervical muscle hypertrophy or degree of involuntary movements, although the injections were considered beneficial in both groups to these syndrome components.

Increased secretion of tumor necrosis factor alpha and interleukin-6 by alveolar macrophages consecutive to the development of the late asthmatic reaction

The late asthmatic reaction (LAR), consecutive to bronchial allergen challenge, is characterized both by the influx of various cells in proximal and distal airways and by the enhancement of bronchial hyperresponsiveness. However, the exact conditions for the development of the inflammatory reaction during the LAR remain to be specified. Since monokines play a key role in inflammatory processes, particularly in the lung, the production of tumor necrosis factor-alpha (TNF-alpha), interleukin; 1-beta (IL-1-beta) and interleukin-6 (IL-6) by alveolar macrophages (AM), collected 18 to 20 hours after exposure to allergen, was evaluated in 15 allergic subjects with asthma submitted to a challenge test with Dermatophagoides pteronyssinus (N = 6) or with wheat flour (N = 9) and in three healthy subjects. After bronchial provocation test, four patients presented no bronchial response (group 1), and six patients, a single early reaction (group 2). In contrast, five patients developed successively an immediate plus a late response (group 3). The monokine production was compared to that from nine allergic subjects with asthma studied at baseline (group 0) and from 11 unchallenged healthy subjects (control subjects). Measurements of cytokines were evaluated for TNF-alpha and IL-1-beta by a specific immunoradiometric assay, whereas IL-6 levels were appreciated by the proliferation of 7TD1 cells. No detectable amounts of TNF-alpha, IL-1-beta, and IL-6 were in bronchial alveolar lavage fluid, even after a tenfold concentration. In contrast, a significant increase of TNF-alpha (10,642 +/- 3127 U/ml) and IL-6 (1250 +/- 427 U/ml) concentrations was noted in AM supernatants from patients exhibiting an LAR (group 3) compared to cells recovered from groups 2, 1, and 0 and to challenged or unchallenged control subjects (805 +/- 244, 995 +/- 521, 1269 +/- 524, 688 +/- 85, and 445 +/- 74 pg of TNF-alpha per milliliter, respectively; 190 +/- 64, 114 +/- 91, 242 +/- 95, 80 +/- 9, and 54 +/- 19 U/ml of IL-6 per milliliter, respectively). No modification of IL-1-beta contents could be detected between the different groups. A significant correlation was detected between concentrations of TNF and IL-6 (r = 0.92; p less than 0.001). These results demonstrate TNF-alpha and IL-6 secretion by AM consecutively to the development of LAR in allergic subjects with asthma, confirming that AMs are activated after allergen challenge.(ABSTRACT TRUNCATED AT 400 WORDS)

Effects of Furegrelate (Upjohn 63557A) on patency and platelet deposition after canine carotid endarterectomy

Platelet deposition upon endarterectomy sites is a likely cause for early postoperative thrombosis, embolism and restenosis. Platelets aggregate by the thromboxane-prostacycline mechanism. Thromboxane synthetase inhibitors which have been safely administered to humans should reduce platelet deposition after surgical therapy and therefore reduce peri-operative mortality and the prevalence of stroke. A randomized prospective controlled trial was designed to determine vessel patency and platelet deposition associated with the use of 3 mg/kg and 30 mg/kg of Furegrelate (Upjohn U63557A) daily in dogs, who were to have carotid endarterectomy. The 46 treated and 46 control dogs had total carotid patency of 96% and 76% respectively (P less than 0.01). Fourteen dogs treated with 30 mg/kg Furegrelate had no occlusions, compared with a 19% prevalence in 13 controls (P less than 0.02). Furegrelate 10 mg/kg significantly lowered platelet aggregation. Platelet deposition was not significantly changed, however. The reason for this disparity was a probable persistence of vessel wall factors which promoted platelet deposition. This approach might therefore lower rates of peri-operative thrombosis but it would be very unlikely to alter the incidence of restenosis or embolism. Further research could be directed towards modifying the stimuli for platelet deposition upon the endarterectomy site.

A population-based study of Stevens-Johnson syndrome. Incidence and antecedent drug exposures

To determine the incidence of Stevens-Johnson syndrome, a descriptive epidemiology study was performed using computerized Medicaid billing data from 1980 to 1984 from the states of Michigan, Minnesota, and Florida. The ratio of persons hospitalized with a discharge diagnosis of erythema multiforme (ICD-9-CM code 695.1) to persons with any claim for medical service was first used as an estimate of the incidence rate of the disease. Then, since the ICD-9-CM code for erythema multiforme includes other illnesses in addition to Stevens-Johnson syndrome and because these illnesses are frequently misdiagnosed, the information provided by a review of medical records for a subset of cases of erythema multiforme was used to determine the proportion of patients with true Stevens-Johnson syndrome. The incidence rates of Stevens-Johnson syndrome were 7.1 (6.1 to 8.2), 2.6 (1.6 to 4.0), and 6.8 (4.3 to 10.3) per million per year in each state, respectively. Penicillins, especially aminopenicillins, were frequently used in the 19 patients judged to be true cases of Stevens-Johnson syndrome. In conclusion, Stevens-Johnson syndrome is a uncommon condition. The excess risk of Stevens-Johnson syndrome due to any drug must, therefore, be very low.

Interaction of SR 33557 with skeletal muscle calcium channel blocker receptors in the baboon: characterization of its binding sites

A procedure for the isolation of primate skeletal microsomal membranes was initiated. Membranes exhibited specific enzymatic markers such as 5'-nucleotidase, Ca++,Mg(++)-adenosine triphosphatase and an ATP-dependent calcium uptake. Baboon skeletal microsomes bound specifically with high-affinity potent Ca++ channel blockers such as dihydropyridine, phenylalkylamine and benzothiazepine derivatives. Scatchard analysis of equilibrium binding assays with [3H](+)-PN 200-110, [3H](-)-desmethoxyverapamil [( 3H](-)-D888) and [3H]-d-cis-dilitiazem were consistent with a single class of binding sites for the three radioligands. The pharmacological profile of SR 33557, an original compound with calcium antagonist properties, was investigated using radioligand binding studies. SR 33557 totally inhibited the specific binding of the three main classes of Ca++ channel effectors and interacted allosterically with them. In addition, SR 33557 bound with high affinity to a homogeneous population of binding sites in baboon skeletal muscle.

Using a claims database to investigate drug-induced Stevens-Johnson syndrome

In order to explore a priori hypotheses about drug-induced Stevens-Johnson Syndrome (SJS), a case-control study was initiated using data from COMPASS, a computerized data base consisting of Medicaid claims data. The records of 3.8 million patients in five U.S. states were searched to identify patients with an inpatient diagnosis of ICD-9-CM code 695.1 (erythema multiforme-EM). Out of the total of 367 cases that were identified, primary medical records for 249 were sought and 128 (51.4 per cent) of these were obtained. The remainder could not be obtained because: in 36 (29.8 per cent) the hospital refused to provide medical records; in 33 (27.3 per cent) there were transcription errors; in 20 (16.5 per cent) the state could not translate the identification number, primarily because the patients lost Medicaid eligibility too long before our request; in 27 (22.3 per cent) the hospital could not locate the patient's record; and in 5 (4.1 per cent) there were other reasons. Of those with a medical record, 121 (94.5 per cent) had a skin diagnosis and 109 (85.2 per cent) had a diagnosis compatible with ICD-9-CM code 695.1 specified on their discharge summary. However, in 35 (27.3 per cent) an expert reviewer felt that the discharge diagnosis was incorrect. In 50 (39 per cent) the computer diagnosis was incorrect. Only 19 (14.8 per cent) were judged by the expert reviewer to truly have Stevens-Johnson Syndrome, and an additional 37 (28.9 per cent) were judged to have erythema multiforme minor. Thus, the computerized diagnosis agreed very well with the diagnoses specified on the discharge summary. However, EM is frequently misdiagnosed, ICD-9-CM code 695.1 contains multiple other diagnoses which are not EM, and much of hospitalized EM is EM minor. Thus, studies of SJS cannot be performed except in patients whose medical records are available.

A patient with massive oral-facial venous malformation

While malformations of the upper airway are rare, they present challenging management problems and have a potentially devastating impact during anesthesia. This case report describes the management of a patient with a massive supraglottic venous malformation as he underwent transvenous embolization.

A pilot study of the prevalence of herpes genitalis among selected groups of patients seeking care in a family practice center

Herpes genitalis is typically studied in patient panels identified at specialized sexually transmitted disease clinics or with information obtained from herpes self-help groups. This article reports the results of a descriptive pilot study of the prevalence of herpes genitalis in family practice. The feasibility of obtaining psychosexual information on sexually transmitted diseases from more than 600 patients from five family practice practices was assessed. These initial data show that in the family practices participating in this study: 1) genital herpes is a low prevalence disease; 2) psychosocial adjustment to the disease among infected persons is usually reported as good, apart from sexual effects; and 3) close to 30% of the study population reported having prior sexually transmitted diseases. Problems involved in generalizing the results of this research and the limitations of conducting collaborative clinical research in family practice settings are reviewed.

Plasmapheresis in a patient with severe asthma associated with auto-antibodies to platelets

Although the pathogenesis of aspirin-sensitive asthma remains to be specified, it is known that in the presence of acetylsalicylic acid or non-steroidal anti-inflammatory drugs, platelets from aspirin-sensitive asthmatics have been described as generating cytocidal mediators that killed parasite targets such as Schistosoma mansoni larvae. Here we report, in a patient with corticosteroid-dependent asthma associated with aspirin sensitivity, the presence of circulating IgE antibodies against 55 kD and 68 kD platelet antigens. In addition, the serum from this patient was shown to contain a factor able to trigger the release of cytocidal mediators from his platelets as well as from normal individual platelets. This platelet stimulatory activity was presumably supported by IgE antibodies or immune complexes. After informed consent the patient was submitted to plasma exchanges. Plasma removal induced clinical improvement, anti-platelet antibody decrease, and the reduction of the platelet stimulatory activity. All clinical symptoms disappeared within 2 weeks. The disease remained quiescent for 2 months, and daily requirements for prednisone (20-5 mg), and beta-agonist (10-16 to 0-1 inhalations) could be kept at a low level follow-up. The plasma exchanges were delayed by 3 mg kg-1 azathioprine with the maintenance of clinical improvement. A relapse occurred after the arrest of immunosuppressive therapy with the reappearance of both asthma attacks and anti-platelet antibodies, as well as the increase of the platelet stimulatory activity.(ABSTRACT TRUNCATED AT 250 WORDS)

Botulinum A toxin for the treatment of spasmodic torticollis: dysphagia and regional toxin spread

Chemodenervation of cervical muscles with botulinum A toxin, although useful in treating spasmodic torticollis, has been associated with dysphagia. Retrospective analysis of dose and injection site (sternomastoid vs. posterior cervical muscle groups) in 26 patients (49 injections) suggested that dysphagia was related to the quantity of toxin injected into the sternomastoid muscle: dysphagia, median 150 IU (7 injections); and no dysphagia, median 100 IU (42 injections; p = 0.026 Wilcoxon test). In a prospective study (31 injections to 24 patients), limiting the dose administered to the sternomastoid to 100 IU, substantially reduced the incidence of dysphagia (0 of 31, p = 0.27, Fisher's exact test). Denervation of human orbicularis muscle fibers, 5 weeks to 4 months after injection of botulinum A toxin for the treatment of blepharospasm, was successfully demonstrated by intense, diffuse acetylcholinesterase staining. A weight-adjusted dose similar to that given for torticollis was injected into longissimus dorsi muscle in 6 albino rabbits. Using the acetylcholinesterase stain as a marker, a diffusion gradient was noted over a distance of 30 to 45 mm from the point of injection and in contralateral muscle 15 to 25 mm from this point. Thus, denervation was demonstrated to occur within a definable area which crossed anatomic barriers, such as fascia and bone. These clinical and laboratory data suggest that dysphagia following botulinum toxin therapy results from toxin spread to pharyngeal musculature from the sternocleidomastoid injection site. Limiting of the injection dose to 100 IU or less to the sternomastoid substantially decreases the incidence of this complication.

Microcomputer database and system of audit for the vascular surgeon

We have set up a vascular database based upon an IBM personal computer in the vascular unit at Repatriation General Hospital, Concord, using 'Dataease'. This is commercially available software that allows the development of a database by users with little or no programming knowledge. The database is menu driven and designed to record details of admissions, indications for surgery, operations, complications and follow-up and has been set up as a prospective project from 1 January 1989 after a pilot study in 1988. Currently, interns, residents and registrars enter data directly onto the computer, providing an excellent teaching and review medium. Unit audit is easy as the program is completely menu driven and there are more than 100 customized reports written, ranging from providing simple complication details to complex reports deriving graft cumulative patency rates. This system also provides for 'instant' discharge letters which have markedly improved communication with the general practitioner.

Lymphocyte-mediated inhibition of platelet cytotoxic functions during Hymenoptera venom desensitization: characterization of a suppressive lymphokine

Recently, it has been shown that platelets, through a receptor for the Fc fragment of IgE, could be specially triggered by venom allergens in hypersensitivity to hymenoptera, generating cytocidal mediators toward Schistosoma mansoni larvae, and oxygen metabolites measured by chemiluminescence. After rush immunotherapy, a depressed platelet response was demonstrated to be associated with the production of lymphokine(s). Here we report the characterization of a factor present in supernatants of antigen-stimulated T cells from patients after hymenoptera venom desensitization which is able to inhibit platelet cytotoxic functions in a dose-dependent manner. The optimal inhibition was observed with supernatants obtained after T lymphocyte stimulated with 10(-5) micrograms venom allergen/ml. Once specifically produced the platelet-suppressive effect of lymphocyte supernatants was not antigen specific. The producing T cell subpopulation was identified as CD8+. This lymphokine had an approximate molecular mass of 25 kDa and a pI of 4.8. It was heat and acid stable and sensitive to trypsin and proteinase K but not to neuraminidase. This platelet inhibitory activity was absorbed by platelet membrane suggesting its binding to a receptor. These properties were very similar to a previously described platelet activity suppressive lymphokine, suggesting the participation of this lymphokine in the mechanisms of rush desensitization.

The abnormal in vitro response to aspirin of platelets from aspirin-sensitive asthmatics is inhibited after inhalation of nedocromil sodium but not of sodium cromoglycate

1. Blood platelets from patients with aspirin-sensitive asthma (ASA) generated cytotoxic mediators in the presence of aspirin. This abnormal in vitro response to aspirin was abolished within 1 h after nedocromil sodium inhalation but not after sodium cromoglycate inhalation. 2. Platelets recovered this reactivity to aspirin by 12 hours after nedocromil sodium treatment of ASA-patients. 3. The in vitro reactivity to aspirin of ASA platelets isolated before inhalation was inhibited in the presence of serum isolated 15 and 60 min after nedocromil sodium inhalation.

Short-term decrease of skin-test sensitivity after rush desensitization in Hymenoptera venom hypersensitivity

Thirty-seven patients with a history of systemic anaphylactic stings were desensitized by the rush method. Patients were evaluated by skin testing twice, before and 6 weeks after desensitization. An additional control group of 10 patients, not yet desensitized, were tested for skin test technique reproducibility at 6-week intervals. Results were compared with IgE and IgG antibody levels, and with platelet reactivity towards specific Hymenoptera venom. Before desensitization, the maximum skin-test sensitivity was observed at 10(-5) micrograms venom/ml in 56% of patients and decreased to 10(-1) micrograms venom/ml after desensitization (48.6% of patients). Decrease of cutaneous tests was observed in 28/37 patients (75%) (P less than 0.001) and was not associated with significant variations of specific IgE or IgG antibody levels, but was correlated with the decrease of platelet reactivity (P less than 0.05). Conversely, variations of skin-test sensitivity in the control group was not significant.

Role of phospholipase A2 and G-proteins in the IgE-dependent activation of mast cells and macrophages

The effect of para-bromophenacyl bromide (a selective inhibitor of phospholipase A2) and pertussis toxin has been investigated on IgE-dependent histamine release and on IgE-dependent macrophage-mediated cytotoxicity. Para-bromophenacyl bromide inhibited dose-dependently IgE-dependent stimulation of mast cells and macrophages (IC50's of 5.0 X 10(-7) M and 2.5 X 10(-7) M, respectively). In contrast, pertussis toxin only inhibited the IgE-dependent stimulation of macrophages, whereas the IgE-dependent activation of mast cells was not affected. These results suggest that the transducing mechanisms following the activation of the high affinity receptor for IgE (Fc epsilon RI on mast cells) as well as the low affinity receptor for IgE (Fc epsilon RII on macrophages) induce the activation of phospholipase A2. Fc epsilon RII might be coupled to a pertussis toxin sensitive G-protein.

Prehospital cricothyrotomy: an investigation of indications, technique, complications, and patient outcome

The records of all patients who presented to a Level 1 trauma center during a two-year period for whom a prehospital cricothyrotomy was attempted or ordered were reviewed. Twenty patients met the study criteria. The average age was 37 years (range, 11 to 65 years). Indications for prehospital cricothyrotomy were massive facial trauma (eight), failed oral intubation (seven), and suspected cervical-spine injury (one). Cricothyrotomy was attempted in 16 patients (80%), with the remaining four having the procedure ordered but not attempted. A successful airway was achieved in 14 patients (88%). Horizontal incisions were used in all cases and were anatomically correct in 15 of 16 attempts (94%). The overall immediate complication rate was 31%. Two patients (12%) sustained major complications (failure to obtain an airway). No hemorrhagic complications occurred, but 16 of the 20 were in cardiac arrest in the field. Long-term complications were not evaluated. All patients sustained major injuries (mean Injury Severity Score, 53.7), except one patient who suffered airway obstruction from food. Three patients (15%) survived; two of the three suffered permanent, severe brain dysfunction. These preliminary findings demonstrate that prehospital cricothyrotomy is being used chiefly in massively injured patients who are already beyond recovery. It is thus difficult to assess whether the procedure is either safe or effective. There is a need for further investigation to determine whether prehospital cricothyrotomy has any beneficial effect on outcome and, if so, in what setting.(ABSTRACT TRUNCATED AT 250 WORDS)