Tachykinins mediate the potentiation of antigen-induced bronchoconstriction by cold air in guinea pigs

The role of tachykinins in the potentiation of antigen-evoked bronchoconstriction induced by inhalation of cold air was studied in guinea pigs. Cold air was delivered through a tracheal cannula to anesthetized, artificially ventilated guinea pigs sensitized with ovalbumin and pretreated with atropine (1.4 micromol/kg). Inhalation of cold air increased total pulmonary resistance (RL) in a time-dependent manner; inhalation of cold air for 10 or 15 minutes, but not for 5 minutes, produced a significant increase in RL. Aerosolized ovalbumin (5 breaths) increased RL in a dose-dependent manner (0.5% to 5%). Inhalation of cold air for 5 minutes significantly enhanced both the peak and the duration of the increase in RL induced by 0.5% ovalbumin. The tachykinin neurokinin 2-receptor antagonist, SR 48968 (0.3 micromol/kg intravenously) inhibited both the peak and the duration of the bronchoconstriction induced by 5-minute inhalation of cold air and ovalbumin (0.5%), whereas it did not affect the response to ovalbumin (0.5%) alone. These findings suggest that exposure to cold air potentiates the bronchoconstriction response to antigen and that this potentiation is mediated by tachykinin release from sensory nerves.

Trends in the utilization of noninvasive cardiac diagnostic tests in Ontario from fiscal year 1989/90 to 1992/93

OBJECTIVE

To describe pattern of utilization of noninvasive cardiac diagnostic test in Ontario.

DESIGN

Retrospective analysis using Ontario Health Insurance Plan (OHIP) administrative data.

SETTING

Ambulatory care settings in Ontario.

MAIN OUTCOME MEASURES

First, the volume of services and expenditures on electrocardiograms (ECG), ambulatory ECG, radionuclide angiocardiograms (RNA), echocardiograms, exercise stress tests (EST), and myocardial perfusion scintigrams from 1989/90 to 1992/93; second, the number and specialty of physicians performing these tests.

MAIN RESULTS

Ontario spent $119 million on noninvasive diagnostic cardiology test in 1992/93, representing 2.67% of total OHIP expenditures. Expenditures on these procedures grew by 49.3 % over the four-year period, exceeding the overall OHIP growth rate, and was most rapid for nuclear cardiology and echocardiography. Changing demographics accounted fpr only a minor portion of expenditure growth. Second, age-adjusted utilization rates for EST, myocardial perfusion scintigraphy and RNA were higher for men, but sex differences tended to diminish over time. Third, utilization rates differed markedly by geographic region, and variations were greatest for nuclear medicine studies. Geographic variations tended to be attenuated over time. There was also wide variation in the frequency with which physicians performed Doppler studies with two-dimensional echocardiography.

CONCLUSIONS

The use of noninvasive cardiac diagnostic test has grown rapidly in recent years. This growth may have been influenced by practice guidelines, by greater diffusion of, and access to, newer technology and by more testing in women. Wide regional variations suggest that clearer practice guidelines are needed concerning the appropriate use of noninvasive cardiac diagnostic investigations.

Cold air-induced bronchoconstriction is mediated by tachykinin and kinin release in guinea pigs

In the present study, we investigated the role of acetylcholine, tachykinins and kinins in the bronchoconstriction induced by cold air inhalation. Cold air was delivered to anaesthetised, artificially ventilated guinea pigs through a tracheal cannula. Inhalation of cold air increased the maximum total pulmonary resistance (RL) in a time-dependent manner, reaching a maximum after 15 min of exposure. The increase in RL induced by exposure to cold air for 10 min was not affected by pretreatment with atropine (1.4 mu mol/kg, i.v.); it was abolished by the tachykinin NK2 receptor antagonist, SR 48968 (0.3 mu mol/kg, i.v.) and was reduced by 58% by the kinin B2 receptor antagonist, HOE 140 (0.1 mu mol/kg, i.v.). These findings suggest that cold air induces bronchoconstriction in guinea pigs via a cascade that involves the release of kinins and tachykinins.

Assessment of the effect of candidate anti-inflammatory treatments on the interaction between meningococci and inflammatory cells in vitro in a whole blood model

A wide range of immunomodulating agents are now available which may be of benefit in reducing inflammatory cell activation in meningococcal sepsis. In order to facilitate selection of candidate anti-inflammatory agents for clinical trials, we have used an in vitro whole blood model to evaluate the effects on meningococcal induced neutrophil and monocyte activation, of dexamethasone, prostacyclin, pentoxifylline and a human IgM anti-lipid A monoclonal antibody (HA-1A). Known concentrations of heat and penicillin killed meningococci were added to whole blood and the time course of cellular activation was determined. Using elastase alpha 1-antitrypsin (elastase-alpha 1-AT) and TNF alpha production as markers of neutrophil and monocyte activation respectively, plasma levels of elastase-alpha 1-AT and TNF alpha were found to increase in a dose-dependent manner. Elastase-alpha 1-AT was detected early, with most release occurring between 15-30 min whereas TNF alpha was detected later, between 120-180 min. Dexamethasone, prostacyclin and pentoxifylline caused a dose-dependent inhibition of TNF alpha release but had no effect on elastase release. HA-1A had no effect on either TNF alpha or elastase release. This model may be useful in determining the sequence of inflammatory cell activation and in selecting candidate anti-inflammatory agents for evaluation in clinical trials.

Role of recruited neutrophils in interleukin-8 production in dog trachea after stimulation with Pseudomonas in vivo

Cell-free supernatant of Pseudomonas aeruginosa (PA) recruits neutrophils into the airways indirectly by inducing the production of chemotactic factors, including interleukin-8 (IL-8). PA products stimulate IL-8 expression selectively in surface airway epithelium, gland ducts, serous cells, and recruited neutrophils. To examine the relative contribution of neutrophils in IL-8 release in the airway lumen, we studied the effect of inhibition of neutrophil recruitment on IL-8 concentration in tracheal fluid after introduction of PA supernatant into the dog trachea in vivo. Tracheal superfusion with PA supernatant caused neutrophil recruitment and increased the IL-8 concentration in the tracheal lumen; NPC 15669 inhibited both effects. To study whether migration of neutrophils into the airway lumen per se induces their expression of IL-8, we compared effects of local introduction of IL-8 and of PA supernatant into the trachea on IL-8 expression in neutrophils recruited into the trachea. PA supernatant, but not exogenous IL-8 alone, induced IL-8 mRNA expression in neutrophils recruited into the trachea. To determine what product(s) of PA stimulate IL-8 expression in neutrophils, we examined neutrophils isolated from peripheral blood. PA supernatant induced IL-8 production in neutrophils, an effect reproduced by PA lipopolysaccharide and inhibited by polymyxin B. These results suggest that neutrophils recruited into the airway lumen play a major role in local IL-8 production in airways in response to bacteria such as PA, depending on the presence of stimuli such as lipopolysaccharide.

Viral infection potentiates the increase in airway blood flow produced by substance P

We examined the effect of respiratory tract infection with Sendai virus on the responsiveness of airway blood flow to substance P (SP) in rats. Pathogen-free rats were inoculated with either Sendai virus suspension or sterile viral growth medium into each nostril. Five days later, we measured airway and esophageal blood flows before and immediately after injection of SP or histamine into the left ventricle of rats in both groups using a modification of the reference-sample microsphere technique. Viral infection potentiated the increase in airway blood flow evoked by SP but not by histamine. We also examined the effect of neutral endopeptidase (NEP) and angiotensin-converting enzyme (ACE) on the SP-induced increase in airway blood flow. Both phosphoramidon (NEP inhibitor) and captopril (ACE inhibitor) potentiated the increase in airway blood flow produced by SP in pathogen-free rats. In the presence of both peptidase inhibitors, a submaximal dose of SP increased blood flow to a similar level in infected and pathogen-free rats. Thus decreased activity of both ACE and NEP may be involved in the exaggerated increase in airway blood flow evoked by SP in virus-infected rats.

Corticotropin-releasing factor inhibits antigen-induced plasma extravasation in airways

We investigated the potential of corticotropin-releasing factor (CRF) to reduce neurogenic plasma extravasation in sensitised guinea pig airways evoked by antigen challenge. Inhalation of 5% ovalbumin for 2 min in the presence of phosphoramidon (2.5 mg/kg, i.v.) increased extravasation of Evans blue dye in the trachea and main bronchi. The increase in plasma extravasation induced by antigen challenge was significantly reduced by pretreatment with CRF (30 nmol/kg, i.v.) (73% in the trachea and 42% in the main bronchi). The inhibition of plasma extravasation by CRF (30 nmol/kg, i.v.) alone was not different from the inhibition induced by the combination of CRF and the tachykinin NK1 receptor antagonist, CP-99,994 (4 mg/kg, i.v.) (73% in the trachea and 38% in the main bronchi). CRF (30 nmol/kg, i.v.) inhibited by 32% in the trachea and by 43% in the main bronchi plasma extravasation induced by aerosolised bradykinin but did not reduce the plasma extravasation caused by aerosolised substance P in the presence of phosphoramidon. These findings suggest that CRF reduces ovalbumin-induced plasma extravasation in guinea pig airways by inhibiting the release of tachykinins from primary sensory nerves.

Inhibition of bronchoconstriction by pituitary adenylate cyclase activating polypeptide (PACAP 1-27) in guinea-pigs in vivo

1. We studied the inhibitory effect of pituitary adenylate cyclase activating polypeptide (PACAP 1-27) on the increase in total pulmonary resistance (RL) caused either by allergen or histamine in anaesthetized, ventilated guinea-pigs. 2. PACAP 1-27 given via i.v. infusion (0.045-4.5 nmol kg-1 min-1) dose-dependently reduced the increase in RL caused by inhaled ovalbumin and histamine. At the highest dose, PACAP 1-27 prevented the increase in RL caused by ovalbumin and histamine completely. Infusion of PACAP 1-27 and the beta 2-adrenoceptor agonist, salbutamol (0.045-4.5 nmol kg-1 min-1) inhibited the increase in RL similarly, but salbutamol increased the heart rate more than PACAP 1-27. 3. PACAP 1-27 and salbutamol given via inhaled aerosol (0.1 mM, 20 breaths) significantly reduced the increase in RL caused by histamine infused i.v., whereas aerosolised sterile saline did not. Both PACAP 1-27 and salbutamol caused bronchodilator effects within 1 min of drug inhalation and these effects remained throughout the 20 min of study. 4. Because PACAP 1-27 produced significant bronchodilatation and rapid onset of sustained action in vivo and without pronounced cardiovascular side effects, we conclude that this peptide may have therapeutic potential as a bronchodilator.

Neutrophil elastase-alpha 1-antitrypsin in middle ear fluid in chronic otitis media with effusion

Neutrophil elastase-alpha 1-antitrypsin was quantified in samples taken from middle ear effusions collected at operation from 17 children attending for elective myringotomy and grommet insertion. At the time of surgery the effusion was classified as serous or mucoid. Children with a recent history of infection or antimicrobial therapy were excluded. The quantification of immunoreactive neutrophil elastase was by means of enzyme-linked immunosorbant assay (ELISA). The mean value of neutrophil elastase-alpha 1-antitrypsin was 50.6 +/- 38.3 (SD) micrograms/ml in mucoid effusions, which was significantly higher (P < 0.05) than that in serous effusions (5.3 +/- 4.8 micrograms/ml). These results indicate that a mucoid effusion may reflect a more severe inflammatory response and that persistence of neutrophil activity in the middle ear mucosa may contribute to the persistence of at least one group of middle ear effusions.

Expression of Trichoderma reesei and Trichoderma viride xylanases in Escherichia coli

Synthetic genes encoding the 190 amino acid Trichoderma reesei xylanase II (TrX) and the closely related Trichoderma viride xylanases have been synthesized in a two-step procedure. Initially, a partial gene encoding amino acids 92-190 was constructed in fusion with the N-terminal half of the Bacillus circulans xylanase (BcX). The remaining BcX gene sequence was replaced during the assembly of the coding sequence for amino acids 1-91. Expression of the synthetic genes in Escherichia coli yielded recombinant xylanases with specific activity generally identical with the natural TrX. However, the recombinant TrX showed thermostability and temperature optimum lower than those of the natural TrX, thus indicating that the posttranslational modifications of the latter in its fungal host are essential to its greater stability. A mutation N19K further decreased the thermostability of the recombinant TrX.

Anterior lung herniation: another aspect of the seatbelt syndrome

Shoulder harnesses can be a source of thoracic injury in motor vehicle crashes. Sternal and rib fractures are most commonly reported. We present a case of a traumatic anterior lung herniation secondary to shoulder harness trauma in a motor vehicle crash victim with multiple injuries. A brief review of lung hernias is provided as well as a brief discussion of the thoracic manifestations of the seatbelt syndrome.

Plasma extravasation in the rat trachea induced by cold air is mediated by tachykinin release from sensory nerves

Cold air was delivered to anesthetized, artificially ventilated, pathogen-free F344 rats via a tracheal cannula. Inhalation of cold air increased Evans blue dye extravasation in the trachea in a time-dependent (1 to 10 min) manner. Plasma extravasation increased after 3 min exposure to cold air and reached a maximum after 10 min exposure. The neutral endopeptidase inhibitor, phosphoramidon (2.5 mg/kg, intravenously), increased by 84% the plasma extravasation induced by inhalation of cold air for 1 min. The plasma extravasation evoked by 5 min exposure to cold air was abolished by the NK1 tachykinin receptor antagonist, CP-99,994 (4 mg/kg, intravenously); was reduced 30% by the B2 bradykinin receptor antagonist, HOE140 (0.1 mumol/kg, intravenously); and was not affected by H1 (pyrilamine, 10 mg/kg, intraperitoneally) or H2 (cimetidine, 10 mg/kg, intraperitoneally) histamine receptor antagonists or the cyclooxygenase inhibitor indomethacin (5 mg/kg, intravenously). In rats infected with Sendai virus, plasma extravasation evoked by inhalation of cold air was greater than in pathogen-free rats. Pretreatment with CP-99,994 (4 mg/kg, intravenously) inhibited completely the plasma extravasation induced by cold air in virus-infected rats. These findings indicate that cold air increases plasma extravasation in the rat trachea by a neurogenic mechanism that involves the release of tachykinins from sensory nerves. Kinin release may also play a role in this neurogenic inflammatory response.

Increase in interleukin-8 and soluble intercellular adhesion molecule-1 in bronchoalveolar lavage fluid from premature infants who develop chronic lung disease

Interleukin-8 (IL-8), soluble intercellular adhesion molecule-1 (sICAM), elastase and neutrophils were assessed in bronchoalveolar lavage fluid from nine infants who developed chronic lung disease (CLD) after respiratory distress syndrome (RDS), seven who had recovered from RDS, and in four control infants. IL-8, sICAM, elastase and neutrophils in bronchoalveolar lavage fluid were increased in the CLD group, the differences being most pronounced at 10 days of age. When babies with and without CLD were compared at 10 days of age, bronchoalveolar lavage fluid from the babies with CLD had significantly increased IL-8 (114.0 vs 12.7 ng/ml), sICAM (19.0 vs 1.1 micrograms/ml), elastase (6.9 vs 0.9 micrograms/ml) and neutrophils (1.9 vs 0.4 x 10(9)/l). In serum the increased concentration of IL-8 observed at birth in the CLD (247 pg/ml) and RDS (192 pg/ml) groups decreased over three weeks to the concentrations observed in the controls (< 70 pg/ml). Persistent inflammation could be a major contributory factor in the development of CLD.

Site-specific N-terminal auto-degradation of human serum albumin

Human serum albumin prepared by blood fractionation for clinical purposes was found to degrade when stored at or above 30 degree C. Mass spectrometry and N-terminal sequencing of the protein identified degradation corresponding to the loss of the first two residues, aspartic acid and alanine. The reaction was shown to be dependent upon temperature and the N-terminal alpha-amino group. In addition, comparison with serum albumins derived from other species showed that the instability of the N-terminus was specific to the human albumin sequence. An intact aspartyl-alanyl dipeptide, purified from degraded albumin solutions, differed substantially from a synthetic dipeptide on amino acid analysis, N-terminal sequencing and NMR. It is suggested that the released dipeptide may be cyclic, implying a novel cleavage mechanism.

Staphylococcus aureus stimulates neutrophil recruitment by stimulating interleukin-8 production in dog trachea

The present study examined whether neutrophil recruitment in dog airways by Staphylococcus aureus is mediated by interleukin-8 (IL-8). S. aureus culture supernatant was superfused into an isolated tracheal segment in six dogs, and neutrophil recruitment and IL-8 concentrations were measured in the superfusate. Dog IL-8 was cloned, expressed in Escherichia coli, purified by chromatography, and shown to be biologically active. With the use of an enzyme-linked immunoabsorbent assay (ELISA) for the measurement of dog IL-8, we showed that S. aureus supernatant induced neutrophil recruitment and increased IL-8 concentration in the superfusate in a time-dependent manner. The chemotactic activity present in the superfusate 6 h after superfusion with S. aureus was inhibited by an anti-IL-8 antibody. S. aureus supernatant also stimulated IL-8 production and gene expression by cultured canine tracheal epithelial cells. These results provide evidence that IL-8 plays a major role in S. aureus-induced neutrophil recruitment in the airways by stimulating IL-8 production in airway cells.

Pseudomonas stimulates interleukin-8 mRNA expression selectively in airway epithelium, in gland ducts, and in recruited neutrophils

Neutrophils may play important roles in chronic airway diseases. Pseudomonas is a common pathogen in some chronic airway diseases, and expression of the neutrophil chemoattractant interleukin-8 (IL-8) is induced by Pseudomonas in various cells in vitro. Here we examine the localization of IL-8 mRNA expression after incubating human and dog bronchi with Pseudomonas supernatant in vitro. To examine IL-8 expression in recruited neutrophils, we also superfused the dog bypassed tracheal segment with Pseudomonas supernatant in vivo and measured neutrophil number and IL-8 concentration in luminal fluid; simultaneously, we introduced Pseudomonas supernatant by catheter in a peripheral airway. After 6 h, we analyzed IL-8 mRNA expression and localization in removed tissue. Unincubated bronchi showed no IL-8 mRNA expression, but incubation with Pseudomonas supernatant in vitro resulted in IL-8 mRNA expression in surface epithelial, gland duct, and a subpopulation of serous gland cells. In vivo, introduction of Pseudomonas supernatant into dog trachea and peripheral airways caused IL-8 mRNA expression in epithelial and gland duct cells but also in the recruited neutrophils. Pseudomonas lipopolysaccharide alone was without effect in vitro and in vivo. We conclude that Pseudomonas products, but not lipopolysaccharide, stimulate IL-8 expression in airways and that this expression occurs primarily in surface epithelial and gland duct cells, thus bringing the chemoattractant to the bacterial site. Furthermore, IL-8 expression in recruited neutrophils provides a potential mechanism for positive feedback of this protective antibacterial response.

Identification of mutations in the alpha 3(IV) and alpha 4(IV) collagen genes in autosomal recessive Alport syndrome

Alport syndrome (AS) is an hereditary disease of basement membranes characterized by progressive renal failure and deafness. Changes in the glomerular basement membrane (GBM) in AS suggest that the type IV collagen matrix, the major structural component of GBM, is disrupted. We recently isolated the genes for two type IV collagens, alpha 3(IV) and alpha 4(IV), that are encoded head-to-head on human chromosome 2. These chains are abundant in normal GBM but are sometimes absent in AS. We screened for mutations in families in which consanguinity suggested autosomal recessive inheritance. Homozygous mutations were found in alpha 3(IV) in two families and in alpha 4(IV) in two others, demonstrating that these chains are important in the structural integrity of the GBM and that there is an autosomal form of AS in addition to the previously-defined X-linked form.

Tachykinins and kinins in antigen-evoked plasma extravasation in guinea-pig nasal mucosa

The plasma extravasation evoked by instillation of 5% ovalbumin in the nasal mucosa of sensitized guinea-pigs was potentiated by the neutral endopeptidase inhibitor, phosphoramidon, and was reduced by the tachykinin NK1 receptor antagonist, CP-96,345. The bradykinin B2 receptor antagonist, HOE 140, also reduced the plasma extravasation evoked by the antigen. The combination of HOE 140 and CP-96,345 did not increase further the inhibition caused by HOE 140 alone. Plasma extravasation evoked by instillation of capsaicin was abolished by CP-96,345. HOE 140 blocked and CP-96,345 markedly reduced plasma extravasation caused by instillation of bradykinin. Plasma extravasation evoked by instillation of substance P was not affected by HOE 140. We conclude that antigen challenge causes plasma extravasation in the nasal mucosa of sensitized guinea-pigs, an effect that is due in part to the release of tachykinins from sensory nerve endings. Our evidence suggests that tachykinin release in response to antigen is provoked mainly by the release of kinins.

Interleukin 6 promotes murine lupus in NZB/NZW F1 mice

To investigate the role of IL-6 in systemic lupus erythematosus (SLE), we selectively inhibited IL-6 in lupus-prone NZB/NZW F1(B/W) mice by chronic administration of a rat mAb to mouse IL-6. Anti-IL-6 alone elicited an anti-rat response that blocked its biologic effects. To circumvent this problem, we rendered B/W mice tolerant to the rat mAb by administration of anti-CD4 concurrent with the first dose of anti-IL-6. Thereafter, the mice received weekly injections of anti-IL-6 alone. There were two control groups: one group received the tolerizing regimen of anti-CD4 along with a control rat IgG1 mAb (GL113) instead of anti-IL-6; the other control group received PBS. Mice that received anti-CD4 were tolerant to the rat mAb for 6 mo. Throughout this period, treatment with anti-IL-6 prevented production of anti-dsDNA, significantly reduced proteinuria, and prolonged life. Mice that received anti-IL-6 without anti-CD4 developed an immune response to the rat mAb and then developed anti-dsDNA antibodies, proteinuria, and mortality comparable with control mice. These findings establish that IL-6 promotes autoimmunity in B/W mice. They further indicate that, although mAb to IL-6 can suppress murine lupus, the development of host immunity to the mAb abrogates its beneficial effects. Finally, this is the first study to demonstrate that a brief course of anti-CD4 can induce tolerance to another therapeutic mAb, in this case an anti-cytokine mAb.

Treatment of murine lupus with monoclonal antibodies to lymphocyte function-associated antigen-1: dose-dependent inhibition of autoantibody production and blockade of the immune response to therapy

Monoclonal antibodies (mAb) to lymphocyte function-associated antigen-1 (LFA-1) have been used successfully in vivo to inhibit immune responses and to block inflammatory reactions. To determine whether these effects of anti-LFA-1 could retard autoimmune disease, we treated lupus-prone NZB/NZW F1 (B/W) mice with a rat mAb to LFA-1 (anti-CD11a). Mice received high-dose therapy (500 micrograms twice weekly), low-dose therapy (40 micrograms thrice weekly), or phosphate-buffered saline from age 5 months to age 10 months. Treatment with high doses of anti-CD11a suppressed both the immune response to the rat mAb and the production of autoantibodies to double-stranded DNA. In contrast, treatment with low doses of anti-CD11a elicited an immune response to the rat mAb and did not suppress autoantibody production. The immunosuppressive effects of high doses of anti-CD11a were not due to target cell depletion. In fact, treatment induced a marked lymphocytosis which involved all lymphocyte subsets equally. Despite inhibiting autoantibody production, high-dose therapy had only modest effects on longevity.

Airway vasodilation by bradykinin is mediated via B2 receptors and modulated by peptidase inhibitors

We studied the effect of exogenous bradykinin on blood flow in the airway microcirculation of anesthetized F344 rats in vivo. We made three successive determinations of airway blood flow and cardiac output using a modification of the reference sample microsphere technique. Injection of bradykinin into the left ventricle increased airway blood flow in a dose-related manner. Pretreatment with the bradykinin B2 receptor antagonist, Hoe 140, completely abolished bradykinin-, but not histamine-induced vasodilation. A bradykinin B1 receptor agonist, [des-Arg9]bradykinin, did not affect airway blood flow. We also studied the effect of inhibitors of angiotensin-converting enzyme (captopril) and neutral endopeptidase (phosphoramidon) on bradykinin-induced vasodilation. Pretreatment with captopril, but not phosphoramidon, potentiated the bradykinin-induced vasodilation. However, the addition of phosphoramidon further potentiated the effect of captopril. We conclude that injection of bradykinin into the left ventricle produces a dose-related vasodilation in the airway microcirculation mediated via B2 receptors, an effect that is modulated primarily by angiotensin-converting enzyme and, to a lesser extent, by neutral endopeptidase.

In vivo imaging of baboon and human dopamine transporters by positron emission tomography using [11C]WIN 35,428

[11C]WIN 35,428 was evaluated as a specific in vivo radioligand for the dopamine transporter site by PET scanning in nonhuman primates and humans. In studies with a baboon (Papio anubis), [11C]WIN 35,428 accumulated in brain regions containing dopamine transporters, i.e., the striata. This accumulation was partially blocked by prior administration of (-)cocaine (4 mg/kg, i.v.). Placement of a unilateral lesion of dopamine-containing nerve terminals with MPTP resulted in a unilateral reduction in [11C]WIN 35,428 accumulation in the striatum on the side of the lesion. Imaging of D2 dopamine receptors with [11C]NMSP in the same MPTP-treated animals showed much less reduction in the postsynaptic D2 dopamine receptors as compared to the much larger reduction in the dopamine transporters labeled with [11C]WIN 35,428. A total of ten normal human volunteers (five males and five females) with ages ranging from 19 to 81 years were studied. The caudate/cerebellar and putamen/cerebellar ratios ranged from 4.4 to 5.7 90 min after injection of the tracer. Preliminary kinetic modeling with arterial plasma sampling resulted in an average binding potential (k3/k4) of 4.98 in the caudate nucleus and 5.13 in putamen. To demonstrate in vivo blockade with dopamine reuptake inhibitors, two subjects received prior oral doses of 6 mg mazindol. Subject 5 had significant reductions of 29% in the caudate/cerebellar ratio at 90 min, 35% in the putamen/cerebellar ratio at 90 min, 45% in the caudate k3/k4 ratio from 6.7 to 3.7, and 46% in the putamen k3/k4 from 4.7 to 2.5. Subject 8 had significant reductions of 20% in both the caudate/cerebellar ratio and the putamen/cerebellar ratio at 90 min. During the human PET studies, a number of neuropsychological tests and physiological measurements were performed. No significant changes were found after administration of the [11C]WIN 35,428 alone. Taken together, these data indicate that [11C]WIN 35,428 is a promising radioligand for future studies of neuropsychiatric disorders that involve the dopamine transporter site.

The use of Glasgow Coma Scale in poisoning

A 12-month prospective study was undertaken to observe current practice and to determine if a Glasgow Coma Scale (GCS) of 8 or less on admission is a useful parameter to predict the need for airway protection in poisoning. For the period of September 1988 to August 1989, there were 414 admissions for poisoning with 3 fatalities (0.7%). A total of 41 patients (10%) were assessed by attending physicians as requiring airway protection. An initial GCS of 8 or less had a sensitivity of 90% and specificity of 95% for predicting the need for intubation. Logistic regression analysis showed an odds ratio of 0.48 for the relationship between GCS and intubation, significant at P < 0.001. In addition, the absence of a gag reflex on admission gave a sensitivity of 70% and specificity of 100% for predicting the need for airway protection. Further analysis showed that the presence or absence of a gag reflex added nothing to the GCS for the prediction of probability for intubation. In conclusion, an initial GCS of 8 or less was found to be a useful guideline for intubation. However, it should be used in conjunction with the clinical context.

Single Crystal Metals Encapsulated in Carbon Nanoparticles

Single-domain microcrystals of LaC(2) encapsulated within nanoscale polyhedral carbon particles have been synthesized in a carbon arc. Typical particle sizes are on the order of 20 to 40 nanometers. The stoichiometry and phase of the La-containing crystals have been assigned from characteristic lattice spacings observed by high-resolution transmission electron microscopy and energy dispersive spectroscopy (EDS). EDS spectra show that La and C are the only elements present. Characteristic interatomic distances of 3.39 and 2.78 angstroms identify the compound inside the nanoparticle cavities as alpha-LaC(2), the phase of LaC(2) that is stable at room temperature. Bulk alpha-LaC(2) is metallic and hydrolytic. Observation of crystals of pure encapsulated alpha-LaC(2) that were exposed to air for several days before analysis indicates that the LaC(2) is protected from degradation bythe carbon polyhedral shells of the nanoparticles. A high percentage of the carbon nanoparticles have encapsulated LaC(2) single crystals. These carbon-coated metal crystals form a new class of materials that can be protected in their pure or carbide forms and may have interesting and useful properties.

Structural and functional characterisation of recombinant human haemoglobin A expressed in Saccharomyces cerevisiae

Recombinant human HbA, produced by co-expressing alpha-globin and beta-globin chains in the yeast Saccharomyces cerevisiae, has been characterised extensively both physically and functionally. Structural studies using N-terminal sequence analysis, peptide mapping, amino acid composition analysis and electrospray MS demonstrated that the recombinant protein was identical to standard HbA purified from erythrocytes. The functional properties of the recombinant protein were assessed using equilibrium and kinetic measurements of oxygen and carbon monoxide binding. The oxygen-binding studies demonstrated that the yeast-derived HbA behaved as a fully functional, cooperative tetramer (Hill coefficient, 2.9), exhibited a normal Bohr effect and response to phosphate, and displayed a rate of oxygen dissociation identical to that of the native human molecule. The recombinant protein also showed the same characteristics of carbon monoxide combination as the standard protein. These studies demonstrate that yeast provides an ideal system for the production of Hb for structural and functional analysis and a potentially useful source of HbA for formulation into a Hb-based oxygen carrier.

Denervation of transplanted porcine lung causes airway obstruction

Lung transplantation can be complicated by a form of small airway obstruction known as bronchiolitis obliterans. We tested the hypothesis that lung denervation causes small airway obstruction in young pigs (10 +/- 1 weeks). Control pigs had an innervated native lobe, and study pigs had either a denervated native lobe or a denervated transplant lobe. Transplanted pigs received standard immunosuppression. At 10 weeks we measured isolated left lobe pulmonary mechanics. Dynamic resistance in both study groups was significantly higher than in the lobectomy group, whereas dynamic compliance in both study groups was significantly lower than in the lobectomy group. No significant difference in resistance or compliance was noted between the transplant and reimplant groups. Histologic changes consistent with rejection were noted in the transplant lobes. We conclude that the small airway obstruction noted in this model is due to operative denervation rather than to immunosuppression or rejection.

[The results of serological studies in different foci of tropical and tertiary malaria]

Attempt was made to determine the value of serologic indices of malaria surveys. Following uniformed methodological and technical approaches 3 foci of P. vivax and 6 foci of P. falciparum malaria were surveyed in different endemic zones of Vietnam and the USSR. It was shown that the most objective criteria for a foci classification is its serologic mean geometric titre. The latter in its turn directly depends of transmission longevity in a foci.

The organization of open complexes between Escherichia coli RNA polymerase and DNA fragments carrying promoters either with or without consensus -35 region sequences

Transcription initiation at the Escherichia coli galP1 promoter does not depend on specific nucleotide sequences in the -35 region. Footprint analysis of transcriptionally competent complexes between E. coli RNA polymerase and DNA fragments carrying galP1 shows that RNA polymerase protects sequences as far upstream as -55, whereas sequences around the -35 region are exposed. In contrast, with galP1 derivatives carrying -35 region sequences resembling the consensus, RNA polymerase protects bases as far as -45, and the -35 region is fully protected. Taken together, our data suggest that the overall architecture of RNA polymerase-promoter complexes can vary according to whether or not consensus -35 region sequences are present; in the absence of these sequences, open complex formation requires distortion of the promoter DNA. However, the unwinding of promoter DNA around the transcription start is not affected by the nature of the -35 region sequence. With a galP1 derivative carrying point mutations in the spacer region that greatly reduce promoter activity, the protection of bases by RNA polymerase around the -10 sequence and transcription start site is reduced. In contrast, protection of the region upstream of -25 is unaffected by the spacer mutations, although sequences from -46 to -54 become hypersensitive to attack by potassium permanganate, indicating severe distortion or kinking of this zone. We suggest that, with this galP1 derivative, RNA polymerase is blocked in a complex that is an intermediate on the path to open complex formation.

Unwinding of duplex DNA during transcription initiation at the Escherichia coli galactose operon overlapping promoters

We have used potassium permanganate as a probe to detect DNA duplex unwinding in vitro, in open complexes between E. coli RNA polymerase and DNa fragments carrying the E. coli galactose operon regulatory region. This zone contains 3 overlapping promoters which specify transcription initiation at 3 distinct startpoints. We have used mutant gal derivatives carrying different single point mutations, each of which allows initiation from only one of the 3 start sites. This has allowed us to compare duplex unwinding in open complexes at the 3 different promoters, and to show that the extent of the unwinding is similar in each case. Further, the pattern of DNA modification by potassium permanganate suggests a model for discrimination between the upper and lower strands. Finally, we show that DNA modification by potassium permanganate at the gal promoters is the same in vivo as in vitro.

Comparison of promoter activities in Escherichia coli and Pseudomonas aeruginosa: use of a new broad-host-range promoter-probe plasmid

The broad-host-range plasmid, pRW2, is a derivative of pRK 2501 carrying the Escherichia coli lac operon without a promoter, downstream of a polylinker sequence. We have cloned a number of DNA fragments carrying promoters into this plasmid and measured promoter activity in both E. coli and Pseudomonas aeruginosa. Promoters carrying consensus -10 and -35 sequences were active in both backgrounds and the dependence of activity on the nucleotide sequence of the 35 region was the same in both cases. We also measured the activity of two promoters at which transcription in E. coli was totally dependent on the E. coli activators CRP and FNR: both promoters were found to be active in P. aeruginosa.

Recognition of nucleotide sequences at the Escherichia coli galactose operon P1 promoter by RNA polymerase

Specific nucleotide (nt) sequences in the -35 region are not essential for galP1 promoter activity, whereas nt sequences in the spacer region are needed for transcription initiation: a G:C base pair at nt -14 and sequences upstream from this position are necessary. In the absence of these sequences, transcription initiation is dependent on the insertion of oligodeoxyribonucleotides carrying -35 region consensus hexamer sequences. Additionally, for maximal promoter activity, specific sequences just upstream from nt -49 are required. Because galP1 carries no sequence resembling the -35 region consensus hexamer, we propose that recognition by RNA polymerase proceeds via an unusual mechanism involving contacts upstream from the -10 hexamer, distortion of the spacer region and a contact upstream from nt -49.

Macrophage/monocyte receptor for nonenzymatically glycosylated protein is upregulated by cachectin/tumor necrosis factor

Proteins of extracellular matrix undergo over time multiple reactions with glucose to form advanced glycosylation endproducts (AGEs) which are highly active in protein crosslinking, and have been implicated in tissue damage associated with aging and diabetes. A macrophage/monocyte receptor for AGE moieties mediates the uptake of AGE-modified proteins by a process that also induces cachectin/tumor necrosis factor (TNF) and IL-1 secretion. Reasoning that cytokines might regulate this AGE-receptor system, we have evaluated the effect of cachectin/TNF, IL-1, and IFN-gamma on AGE-protein processing. We report that cachectin/TNF induced a severalfold enhancement of binding, endocytosis, and degradation of AGE-BSA by both murine peritoneal macrophages and human blood monocytes in vitro, and that cachectin/TNF enhanced the rate of disappearance of AGE-modified red blood cells in vivo. IL-1 and IFN-gamma alone did not increase AGE processing, but IFN-gamma consistently enhanced cachectin/TNF-induced changes in AGE-receptor kinetics. Similar effects were induced by AGE-BSA and FFI-BSA, a chemically synthesized AGE, when used as macrophage stimulants, possibly via cachectin/TNF induction. All upregulatory responses were blocked by anticachectin/TNF monoclonal antibody. These data suggest that AGE-induced cachectin/TNF, in addition to influencing tissue regeneration and remodelling, may also normally regulate the disposal of tissue damaging AGE-proteins through an autocrine upregulation.

Dissociation of authentic and artifactual effect of circulating heparin on drug protein binding

The purpose of this study was to dissociate the authentic and artifactual effect of in vivo heparin on drug protein binding using protamine as an inhibitor of ex vivo lipolysis. A mixture of ethylenediamine tetra-acetic acid (EDTA, 5 mg ml-1) and protamine in the concentration range of 0 to 7.5 mg ml-1 was added to blood samples from 23 cardiac catheterized patients before (control) and 10 min after 3000 IU of intravenous heparin. In control samples, protamine does not interfere with the protein binding of lidocaine (L), quinidine (Q) or propranolol (P) when plasma pH is readjusted to 7.4. In the absence of protamine, heparin induced a significant increase in the free fraction by 40, 130, and 30 per cent for L, Q, and P, respectively (p less than 0.001), while free fatty acid (FFA) levels increased 2 to 6 fold. When protamine was present, the heparin-induced elevation in free fraction was significantly lower for L (16 per cent) and Q (77 per cent) but not for P; FFA levels were decreased at all protamine concentrations. Residual increases in free fraction and FFA levels compared to control values may represent the true in vivo effect of heparin at the peak activity of lipoprotein lipases. For L and Q, variations in free fraction were strongly associated with variations in FFA, but for P, no significant correlation was observed (r = 0.492). These results indicate that variations in free fraction of L and Q caused by heparin are, to a large extent, artifactual but may be prevented by use of protamine in collection tubes (5 to 7.5 mg ml-1). For P, the increase in free fraction was not mediated by variations of FFA indicating that another mechanism must be involved.

Alterations in the binding site of the cyclic AMP receptor protein at the Escherichia coli galactose operon regulatory region

Gene manipulation techniques have been used to alter the binding site for the cyclic AMP-cyclic AMP receptor protein complex (cAMP-CRP) at the regulatory region of the Escherichia coli galactose (gal) operon. The effects of these changes on CRP-dependent stimulation of expression from the galP1 promoter in vivo have been measured, and gel binding assays have been used to measure the affinity of cAMP-CRP for the modified sites. Firstly we have deleted progressively longer sequences from upstream of the gal CRP site in order to locate the functional limit of the site. A deletion to -49, removing the first base that corresponds to the consensus sequence for a CRP binding site, is sufficient to reduce CRP binding and block CRP-dependent stimulation of P1. Secondly, we used synthetic oligonucleotides to invert the asymmetric nucleotide sequence at the gal CRP binding site or to make the sequence symmetric. Inversion of the site has little effect on CRP binding, the architecture of open complexes at P1 revealed by DNAase I footprinting, or the stimulation of transcription from P1. Making the site symmetric increases the affinity for CRP by over 50-fold and leads to increased transcription from P1, whilst hardly altering the DNAase I footprint of open complexes. Our results confirm that the strength of binding of CRP depends on the nature of the site and show that it is this that principally accounts for differences in CRP-dependent stimulation of transcription.

Changes in circulating alphafetoprotein and human chorionic gonadotrophin following chorionic villus sampling

Chorionic villus sampling (CVS) is rapidly becoming established as a routine procedure for first-trimester fetal diagnosis. The technique can result in fetomaternal haemorrhage and this might sensitize Rhesus-negative mothers and on occasion lead to spontaneous abortion. Serial sampling indicates that there is a rapid rise in alphafetoprotein (AFP) levels following CVS; however, this is not reflected by raised levels at 16-18 weeks and does not influence the subsequent pregnancy outcome. Unlike AFP, alterations in hCG levels are small and variable. Anti-D prophylaxis for non-sensitized Rhesus negative mothers should be given after CVS and the procedure may be contra-indicated in patients who are already sensitized.

Functional analysis of different sequence elements in the Escherichia coli galactose operon P2 promoter

Starting with a DNA fragment containing the galactose operon P2 promoter, we made a series of deletions that progressively replaced DNA sequences upstream of the transcription startpoint and determined their effects on P2 activity. The results show that specific sequences upstream of -32 are not important. Removal of the sequence 5'-CACA-3' from -32 to -28 reduces P2 activity by 50%: longer deletions to -16 further reduce activity but do not remove the information specifying the transcription startpoint. DNA sequences between -32 and -16 at gal P2 assist the isomerization of RNA polymerase from closed to open complexes rather than contributing to the initial binding of RNA polymerase. The activity of gal P2 in the absence of -35 region sequences is dependent on the sequence TG just upstream of the -10 hexamer, TATACT: a mutation at -14 changing the TG sequence to TT totally inactivates P2. However, P2 activity can be restored if the consensus -35 region sequence TTGACA is cloned 17 bp upstream of the -10 hexamer. Thus, for transcription initiation, the -10 hexamer, TATACT, must 'cooperate' with upstream sequences that may be located either around -35 or -14.

A novel whole blood capillary technic for measuring the prothrombin time

The prothrombin time (PT) is frequently performed to monitor anticoagulant therapy. Although relatively simple to perform, it requires venipuncture and laboratory resources for sample handling and analysis. A recently developed capillary whole blood device that uses fingerstick samples was evaluated. Paired capillary whole blood and reference plasma PTs were performed in 858 samples from 732 subjects. The PT for normal volunteers (n = 193) was 11.8 +/- 0.9 seconds with the use of the new instrument and 12.1 +/- 0.5 seconds with the use of the reference method. In samples from 539 patients receiving anticoagulants, the correlation coefficient between the two methods was 0.96. Venous whole blood without anticoagulant and capillary whole blood gave equivalent results, which suggests that the fingersticks do not effect the quality of the specimen. Variation in hematocrit between 23.4% (0.34) and 53.8% (0.538) did not alter the performance of the instrument. The new instrument is easy to use and may allow testing by nonlaboratory personnel and patients. It obviates the need for venipuncture, provides immediate results, and appears to be comparable in accuracy to current reference methods.

RNA polymerase makes important contacts upstream from base pair -49 at the Escherichia coli galactose operon P1 promoter

A G:C to T:A transversion at bp position -19 in the gal operon promoter region relieves the dependence of galP1 promoter activity on the cAMP-CRP complex. Deletion analysis shows that expression from the promoter is decreased on replacement of the sequence between 49 and 54 bp upstream from the P1 start point. Moreover, protection experiments show that RNA polymerase interacts with this region in open complexes at P1. We propose that this contact is necessary for optimal P1 activity; point mutations in the gal promoter region can alter DNA flexibility and hence the strength of this contact; CRP factor activates P1 transcription by favouring formation of this contact; and the gal repressor blocks P1 activity by binding to this zone.

Scatter distribution in transmission measurements with positron emission tomography

The distribution of scattered radiation was measured for transmission scans in positron emission tomography by adding the scattered radiation distributions in different projections from line source experiments. It is shown that in a 20 cm diameter water-filled phantom the scattered radiation effects contribute approximately one-third of the events centrally in the field of view. This may lead to systematic errors of the order of 15-25% in reconstructed images. A scheme for correction for scattered radiation effects in the transmission scans is described and tested in phantom experiments.

Mutations that reduce expression from the P2 promoter of the Escherichia coli galactose operon

We describe the isolation and characterisation of twelve different mutations that reduce gene expression from the galP2 promoter, starting with a gal regulatory region with a mutation that inactivated galP1, the cAMP-CRP-dependent promoter. Seven of the new mutations reduce the initiation of transcription at P2 whereas the others reduce translation initiation of the first gal operon gene, galE. Two of the mutations affecting translation fall in the galE initiation codon and the Shine-Dalgarno sequence. Mutations that allow the formation of a stem-loop structure in the messenger including this sequence also reduce translation. A deletion of 11 bp, upstream of the Shine-Dalgarno sequence, almost totally prevents translation. Although none of the point mutations that reduced transcription initiation at P2 fall in the -35 region, we repeatedly isolated insertions in this zone. The point mutations all fell around the -10 region: the strongest effects were found with mutations that altered the sequence away from the consensus that has been established for Escherichia coli promoters. The effects of the two strongest P2 mutations were investigated in the absence of the P1 mutation used for their isolation. One mutation, a T:A to C:G transition at -12, inactivates both P2 and P1. In contrast the other, a T:A to G:C transversion at -19, specifically inactivates P2, but leaves P1 partially active even in the absence of cAMP-CRP. The implications of this are discussed in the context of how cAMP-CRP controls the balance between transcription from P2 and P1 at the gal operon regulatory region.

Effect of vagal blockade on food- and hormone-stimulated release of pancreatic polypeptide and motilin in dogs

Vagal control of food- and hormone-stimulated release of pancreatic polypeptide (PP) and motilin was investigated in four conscious dogs by examining the effect of cryogenic vagosympathetic blockade. The postprandial PP response of 189 +/- 7 pM was totally, although reversibly, inhibited to 58 +/- 11 pM with the vagi blocked. Similarly, bombesin-, CCK-OP-, or neurotensin-stimulated PP release was abolished. Although the PP response to intraduodenal perfusion of an elemental diet was also reduced by blockade, the 52 +/- 15% inhibition was less than observed with the meal. In contrast to PP, plasma motilin fell after the meal from a fasting level of 128 +/- 16 pM to a nadir of 52 +/- 7 pM. Vagal blockade reversed this decline as plasma motilin rose to a peak of 121 +/- 18 pM with a pattern resembling the motilin response in the interdigestive state. This motilin increment during blockade was inhibited by atropine and by infusion of porcine PP. Plasma motilin also fell with the elemental diet, but this response was not affected by blockade. During infusion of bombesin, plasma motilin rose by 60 +/- 9 pM; vagal blockade augmented this increment twofold. Thus, the PP response to a meal and to hormonal stimulation is controlled by a vagal cholinergic excitatory pathway. However, intestinal release of PP is mediated in part by the vagus and in part by a vagally independent mechanism which may be neural or hormonal. Alternatively, vagal noncholinergic inhibition is a major mechanism modulating the motilin response after oral food but motilin release exclusively from intestinal nutriments is mediated by nonvagal, noncholinergic mechanisms.(ABSTRACT TRUNCATED AT 250 WORDS)

Can potentially infectious specimens containing hepatitis B virus be identified on the basis of their biochemical profile?

The potential infectivity of 1129 randomly selected plasma specimens was directly assayed by hepatitis B virus (HBV) DNA dot-hybridization. Presence or absence of HBV was then correlated with a biochemical profile of 20 common analytes obtained on these same specimens. We found that potentially infectious specimens could not be identified on the basis of any combination of simple biochemical tests; indeed, the infectious specimens were more "normal" in some tests of liver function than were the non-infectious specimens.

Can potentially infectious specimens containing hepatitis B virus be identified on the basis of their biochemical profile?

The potential infectivity of 1129 randomly selected plasma specimens was directly assayed by hepatitis B virus (HBV) DNA dot-hybridization. Presence or absence of HBV was then correlated with a biochemical profile of 20 common analytes obtained on these same specimens. We found that potentially infectious specimens could not be identified on the basis of any combination of simple biochemical tests; indeed, the infectious specimens were more "normal" in some tests of liver function than were the non-infectious specimens.

The role of vagal integrity in gastrin releasing peptide stimulated gastroenteropancreatic hormone release and gastric acid secretion

The role of the vagus nerve in the control of gastrin releasing peptide (GRP) stimulated gastroenteropancreatic hormone release and gastric acid secretion was investigated in four conscious gastric fistula dogs using a technique of bilateral cryogenic vagal blockade. A 90-min infusion of GRP at a dose of 400 pmol X kg-1. h-1 produced significant elevations in plasma levels of gastrin, motilin, GIP, enteroglucagon, insulin, pancreatic glucagon, pancreatic polypeptide and VIP. Vagal blockade reversibly inhibited the rise of plasma PP and significantly blunted the elevation of plasma VIP. However, the GRP stimulated response of the other hormones investigated was not modified by vagal blockade. Similarly, the substantial secretion of gastric acid observed with GRP was not influenced by vagal blockade. Thus GRP acts predominantly via mechanisms which are independent of vagal integrity, findings that are in support of a major role for the local neuromodulation of hormone release and gastric acid secretion.

Simultaneous or sequential expression of lymphoid and myeloid phenotypes in acute leukemia

Acute mixed myeloid-lymphoid leukemia is uncommon. We report four cases in which myeloid and lymphoid cell markers were observed simultaneously or sequentially when 94 patients with acute leukemia were phenotyped according to the French-American-British (FAB) classification system, with cytochemical stains, and with immunologically defined differentiation markers (identified by monoclonal antibodies and antiterminal deoxynucleotidyl transferase [TdT]). In one case, conversion from acute lymphoblastic leukemia to acute myeloid leukemia was noted (FAB L1, TdT+ to FAB M4, Auer rods, TdT-). In another patient, two distinct populations of myeloid and lymphoid blast cells were observed simultaneously (TdT-, LeuM1+/TdT+, LeuM1-). In two additional patients, acute leukemia was characterized by the expression of both lymphoid and myeloid markers on the same cell (TdT+/Leu M1+, B4+/Leu M1+ and greater than or equal to 70% TdT+, T11+, My9+). The Philadelphia (Ph1) chromosome was negative in all cases, though other chromosomal abnormalities were noted in three out of four cases. Malignant transformation of a pluripotential stem cell for both lymphoid and myeloid lineages, with or without the Ph1 chromosome marker, could explain the coexistence of distinct populations of lymphoblasts and myeloblasts in acute leukemia. Acute leukemia with a biphenotypic profile may reflect genome depression accompanying neoplasia.