CD4+ T cells can induce airway hyperresponsiveness to allergen challenge in the brown norway rat

Airway hyperresponsiveness to inhalational challenge with methacholine (MCh) develops by 32 h after allergen challenge of actively sensitized BN rats. To test the hypothesis that CD4+ T cells mediate allergen-induced hyperresponsiveness independent of IgE-mediated mechanisms, we administered CD4+ T cells, CD8+ T cells, and a mixture of CD4+ and CD8+ T cells (total T cells) isolated from the cervical lymph nodes of rats sensitized with ovalbumin (OA) to naive BN rats that underwent aerosol challenge with either OA or bovine serum albumin (BSA) 2 d later. Responsiveness to MCh was measured 2 d before transfer of T cells and 32 h after challenge with OA or BSA. Airway responsiveness increased significantly in recipients of CD4+ T cells after OA challenge, but not in any other of the treatment groups. Analysis of bronchoalveolar lavage (BAL) cells for major basic protein expression by immunostaining showed eosinophilia in OA-challenged CD4+ and total T-cell recipients. Cells retrieved by bronchoalveolar lavage showed increased expression of IL-5 mRNA (in situ hybridization) in CD4+ T cell recipients after OA challenge compared with other groups. Interferon-gamma mRNA was expressed to the greatest extent in CD8+ recipients, but it was elevated in both OA- and BSA-challenged animals. We conclude that CD4+ T cells can induce airway hyperresponsiveness after inhalational challenge with allergen and this is associated with IL-5 production and eosinophilia. CD8+ T cells may have a negative regulatory effect on responsiveness, possibly mediated by interferon-gamma.     

Strain dependence of pseudoelastic hysteresis of NiTi

This work investigated the transformation-strain dependence of the stress hysteresis of pseudoelasticity associated with the stress-induced martensitic transformation in binary NiTi alloys. The strain dependence was studied with respect to the deformation mode during the stress-induced martensitic transformation, which was either localized or homogeneous. It was observed that the apparent stress hysteresis of pseudoelasticity was independent of the transformation strain within the macroscopic deformation range, for the specimens deformed in a localized manner. For specimens macroscopically deformed uniformly, the stress hysteresis of pseudoelasticity increased continuously with increasing strain from the beginning of the stress-induced martensitic transformation. The transformation-strain independence of the stress hysteresis for localized deformation is ascribed to be an artificial phenomenon, whereas the transformation-strain dependence of the hysteresis for uniform deformation is believed to be intrinsic to the process of stress-induced martensitic transformation in polycrystalline materials. This intrinsic behavior is attributed to the polycrystallinity of the materials.     

Depressive response to physostigmine challenge in borderline personality disorder patients

The purpose of this study was to examine the relationship between mood and hormonal responses to cholinergic challenge with physostigmine in order to assess cholinergic system responsiveness in borderline personality disorder (BPD) patients, other non-BPD personality disorder patients, and normal controls. Thirty-four personality disorder patients, 10 of whom met criteria for BPD and 24 of whom met criteria for other, non-borderline, personality disorders, and 11 normal controls participated in a double blind, placebo controlled physostigmine challenge paradigm. The Profile of Mood States depression subscale (POMS-D) self report measure was obtained at baseline and following the physostigmine or placebo infusions. A repeated measures ANOVA of POMS-D scores in placebo and drug conditions indicated a significantly greater depressive response in the total cohort of personality disorder patients than in the normal comparison group (p < 0.05). However, the depressive response to physostigmine was significantly greater in BPD patients, but not other personality disorder patients, compared to normal controls (p < 0.05). There was a correlation between the peak placebo-corrected depressive response to physostigmine and a group of BPD traits related to affective instability but not a group of BPD traits related to impulsivity. There was no correlation in any group between mood response to physostigmine and changes in plasma cortisol, prolactin, or growth hormone, or to nausea or other side effects following physostigmine infusion. These data suggest that there is an association between BPD and acute depressive responses to physostigmine challenge, and that the cholinergic system may be involved in the regulation of affect in Axis II disorders.     

Vasopressin response to 2-deoxy-D-glucose in the rat

The effect of 2-deoxyglucose (2DG) upon plasma arginine vasopressin (AVP), measured by a specific and sensitive RIA, has been studied in unanesthetized male Sprague-Dawley rats. Injection of the drug ip at a dose of 100 mg/kg BW caused a 10-fold rise in plasma AVP to 23.4 +/- 4.9 pg/ml (mean +/- SD). This effect was associated with a rise in plasmas osmolality to 301.8 +/- 3.9 mosmol/kg, but this change was accounted for totally by a rise in plasma glucose to 17.3 +/- 3.0 mM and in plasma urea to 3.4 +/- 0.4 mM. The only effective solute, plasma sodium, fell to 135.0 +/- 0.8 mM. Idiogenic osmoles did not change. Blood volume was reduced by about 5%, while PRA and mean arterial pressure did not change. Thus, the rise in plasma AVP caused by 2DG was not mediated by osmotic or hemodynamic stimuli. Treatment with propranolol (2.5 mg/kg BW) 15 min before 2DG completely abolished the AVP response. These results indicate that 2DG stimulates AVP release by a primary mechanism different from that which mediates the effect of insulin-induced hypoglycemia on AVP.     

Antigen-specific immunoglobulin-A prevents increased airway responsiveness and lung eosinophilia after airway challenge in sensitized mice

The aim of this study was to examine the role of dopamine neurotransmission in the effects of morphine in the learned helplessness paradigm in rats, a generally recognized model of depression. In this model, rats first exposed to inescapable shocks (stressed rats) exhibited an escape deficit in a subsequent shuttle-box test performed 48 h later for 3 consecutive days. The numbers of escape failures and intertrial crossings (motor activity during each intertrial interval) were recorded. Morphine was injected twice daily for 5 days (6 mg/kg/day, s.c.), and haloperidol, a preferential D2-dopamine receptor antagonist, was injected i.p. 15 min before each shuttle-box session. At the highest dose tested (150 microg/kg) haloperidol mimicked the behavioral deficit produced by inescapable shocks. A 37.5 microg/kg dose of haloperidol, which was ineffective by itself, reversed the morphine-induced improvement of escape behavior in previously stressed rats and the morphine-induced increase in intertrial activity in both stressed and nonstressed animals. These results support roles (a) for a dysregulation of dopaminergic neuronal activity in the expression of escape deficit subsequent to an inescapable aversive situation, and (b) for a dopaminergic mediation in the effects of morphine in the learned helplessness paradigm.     

Frequency dependence of specific airway resistance in a commercialized plethysmograph

Specific airway resistance (sRaw) measured by body plethysmography has been shown to decrease markedly with decreasing breathing frequency when the inspired air is not conditioned to body temperature, atmospheric pressure and saturation with water vapour (BTPS). The phenomenon has been attributed to noninstantaneous gas warming and wetting in the airways. The aim of this investigation was to assess whether the phenomenon was also present in a commercialized plethysmograph featuring an "electronic BTPS correction". Airway resistance (Raw) and sRaw were measured in 15 healthy subjects at six breathing frequencies ranging 0.25-3 Hz, using a constant volume plethysmograph in which a correction for non-BTPS gas conditions was applied by electronically flattening the box pressure-airway flow loop (Jaeger Masterscreen Body, version 4.0). The temperature and water vapour saturations in the box averaged 26.5 +/- 1.3 degrees C and 59 +/- 6%, respectively. Raw and sRaw exhibited a clear positive frequency dependence in all but one subject. From 0.25 to 3 Hz Raw increased from (mean+/-SD) 0.62 +/- 0.55 to 1.71 +/- 0.76 hPa x s x L-1 (p<0.001), and sRaw from 2.34 +/- 1.90 to 7.55 +/- 3.08 hPa x s (p<0.001). The data are consistent with a simple model, in which gas conditioning in the airways and external dead space occurred with a time constant of 0.39 s. We conclude that the electronic BTPS correction of the instrument was inadequate, probably because it is assumed that gas conditioning in the airways is instantaneous. We recommend that, with similar instruments, airway resistance be measured using as high a panting frequency as feasible.     

Fatigued? A warm response to auto industry challenge

One of the popular themes at the PM World Congress in Orlando was the study of fatigue behaviour of PM steels. Various aspects of this subject were discussed in over half a dozen sessions. A selection from these papers is reviewed here by Joe Capus…     

Frequency dependence of total respiratory resistance in early airway disease

Patients who develop frequency dependence of lung compliance will theoretically have frequency dependence of pulmonary resistance. We investigated the ability of the simpler, noninvasive measurement of frequency dependence of total respiratory resistance to identify subjects with frequency dependence of compliance. Ten healthy nonsmokers, 14 asymptomatic smokers, and 6 patients with obstructive airway disease were studied. Frequency dependence of total respiratory resistance was determined by the superimposed oscillating airflow technique at 3 to 9 cycles per sec, and frequency dependence of lung compliance was determined by measurements at 10 to 80 breaths per min. Spirometry, airway resistance, closing volume, and closing capacity were also measured. Frequency dependence of lung compliance and total respiratory resistance were closely correlated (P less than 0.001, r = 0.82), but closing volume, closing capacity, spirometry, and airway resistance could not be used to identify subjects with abnormal frequency dependence of lung compliance. Measurements of frequency dependence of total respiratory resistance and lung compliance, total respiratory resistance at 3 cycles per sec, and closing volume minus expiratory reserve volume were able to distinguish significantly between the smokers and the nonsmokers, but spirometry, closing volume, closing capacity, and airway resistance could not. These data indicate that in asymptomatic smokers and subjects with obstructive airway disease, frequency dependence of lung compliance can be predicted from measurements of frequency dependence of total respiratory resistance. These two tests appear to have equivalent sensitivity and selectivity in detecting the uneven time constants in the airways of asymptomatic smokers.     

Tail artery response to sound in the unanesthetized rat

Arterial pulsations have been recorded indirectly from the surface of the rat's tail. Slight heating of restrained unanesthetized rats produces vasodilatation and large amplitude pulsations that are influenced by sensory stimuli, in this case, sound. The surface-recorded pulse volume was found to be proportional to pulse pressure, indicating vasoconstriction as the cause of the decline of the pulse amplitude. A one-second noise burst elicited vasoconstriction, the duration of which was proportional to sound level and occurred as low as at hearing threshold. Under the specified conditions, reproducibility was good with no significant habituation both within session, and between sessions with a one week interval. The warming of the rats was found to be critical for the sound-elicited reactions; responses were obtained only within a narrow, individual temperature-range. The possibilities of using tail vasoconstriction for evaluation of hearing was pointed out, as well as for studies of noise effects on peripheral circulation.     

The response of the rat tail to hyperthermia

When the cartilage of the tail of a baby rat is exposed to temperatures between 41 degrees C and 46 degrees C either necrosis or a small degree of stunting in growth may occur. Isoeffect curves relating time and temperature for both these endpoints for normal and clamped tissue were found to be parallel, a doubling of heating time or an increase in temperature of 1 degree C having the same effect in all cases. Clamping sensitizes the tails by a factor of about three in heating time, equivalent to a temperature difference of 1.5 degrees C. Arrhenius plots show an inactivation energy of 140 kcal/mole. This is similar to that found by other workers using different endpoints, and supports the suggestion that protein denaturation is a critical target for direct heat damage.     

The occurrence of late asthmatic response to exercise after allergen challenge

OBJECTIVES: To evaluate the correlation between the pathological findings of stereotactic core needle biopsy (SCNB) and the prebiopsy mammographic findings, as well as the pathological findings of lesions that were subsequently removed by surgical excision. DESIGN: A retrospective review of 97 consecutive patients who underwent 100 SCNBs of suspicious nonpalpable mammographic lesions. The criterion standard is surgical excisional biopsy with needle localization. Mammographic findings were graded according to the American College of Radiology Breast Imaging Reporting and Data System. The pathological findings of SCNB were categorized into 4 groups: benign and specific, benign and nonspecific, premalignant, and malignant. Surgical excision of the lesion was performed if the pathological finding on SCNB was nonconcordant with the prebiopsy mammogram and when premalignant or malignant lesions were found. The pathological findings of lesions that were subsequently removed by surgical excision were compared with those of SCNB. SETTING: Community-based private multispecialty ambulatory practice. PATIENTS: A population-based sample composed of 97 patients who had grade III, IV, or V lesions on routine screening mammograms. INTERVENTION: Stereotactic core needle biopsy of nonpalpable mammographic lesions. MAIN OUTCOME MEASURES: Percentage of patients whose SCNB results were concordant with the mammographic findings and the pathological findings on subsequent surgical excision. RESULTS: Concordance between SCNB and mammography occurred in 97% of biopsy specimens. Concordance between the pathological findings of SCNB and those of surgically excised lesions occurred in 92.5% of biopsy specimens. We had 1 false-negative result. We had no false-positive diagnosis of cancer with SCNB. CONCLUSION: On the basis of accumulating literature and our own initial experience, SCNB is a promising, safe, and cost-effective procedure.     

How inhomogeneities and airway walls affect frequency dependence and separation of airway and tissue properties

It has been proposed that during mild-to-moderate bronchoconstriction one can partition airway and tissue properties on the basis of input impedance (Zin) acquired from 0.1 to 5 Hz (K.R. Lutchen, B. Suki, Q. Zhang, F. Peták, B. Daróczy, and Z. Hantos. J. Appl. Physiol. 77: 373-385, 1994). The approach is to apply a homogeneous lung model that contains airway resistance and viscoelastic tissue damping and elastance parameters. The tissue parameters account for the frequency dependence in lung resistance (RL) and elastance (EL). We present an anatomically consistent asymmetrically branching airway model to address two key questions: 1) How will lung inhomogeneities, airway wall shunting, and tissue viscoelasticity contribute to increased frequency dependence and levels of RL and EL during lung constriction? and 2) How much can lung inhomogeneities and airway wall shunting contribute to our assessment of airway, tissue, and overall lung properties derived from Zin? The model incorporates nonrigid airway walls and allows for explicit control over the type and degree of inhomogeneous airway constriction or tissue changes. Our results indicate that, from 0.1 to 5 Hz, airway wall shunting does not become important unless the entire lung periphery experiences significant constriction. Mild-to-moderate inhomogeneous peripheral airway constriction produces a relatively minor additional frequency dependence in RL and EL beyond that due to the tissues alone. With more extreme constriction, however, there is a marked frequency-dependent increase in EL. This phenomenon may render it impossible to distinguish from a single frequency measurement whether an increase in EL during bronchoconstriction is a consequence of a true increase in tissue stiffening or simply a consequence of airway phenomena. Finally, Zin from 0.1 to 5 Hz can be used to provide a reasonable separation of airway and tissue properties for mild-to-moderate homogeneous or inhomogeneous lung constriction. However, during more severe disease, inhomogeneities and/or wall shunting will produce substantial overestimation of tissue damping and hysteretic properties. In fact, the only reliable indicator of a real change in the tissues may be a change in the estimate of tissue elastance that is based on data extending to a sufficiently low frequency.     

Effects of ibuprofen on airway vascular response to cotton smoke injury

We studied the effects of ibuprofen on bronchial blood flow and myocardial function after inhalation injury. Sheep (n = 12) were chronically instrumented with cardiovascular and pulmonary catheters. After 5 days of recovery period, baseline data were collected and the sheep were divided into two groups. Group S (n = 6) were insufflated with 48 breaths of cotton smoke; while group I (n = 6) were pretreated with ibuprofen (12mg/kg bolus followed by 3 mg/kg/h continuous infusion for 24 h) and challenged with the same dose of smoke. All the animals were studied for 24h. Bronchial blood flow increased significantly in both groups throughout the experimental period; while stroke volume as well as right and left ventricular stroke work indices of both groups were significantly decreased (group I worse than group S) in the second half of the experimental period. These data suggest that vasodilatory prostaglandins do not play a major role in the bronchial vascular response to smoke inhalation injury and myocardial depression seen post injury is worse in animals treated with ibuprofen.     

Antibody-mediated secondary eosinophilic response to Taenia taeniaeformis in the rat

An experimental model for neoplastic pleural effusion was made using a transplantable pleural fibrosarcoma MC-106 in ddO mice, and a local immunotherapy of neoplastic pleural effusion with oil-attached BCG cell-wall skeleton was attempted. Viable cells (3 X 10(5)) of MC-106 were injected into the right pleural cavity of the mice on day 0 with a tuberculin syringe which was joined to a two-way tap attached to a capillary manometer. All of the mice in the control group, which received intrapleurally saline solution 24 hr after the injection of tumor cells, died within 24 days and the mean survival time was 16.9 +/- 3.4 (SD) days. Macroscopically massive blooded pleural effusion in both pleural cavities and multiple tumor nodules on the surface of parietal and visceral pleura were observed. On the other hand, the mice which received intrapleurally 100 mug of oil-attached BCG cell-wall skeleton 24 hr after the injection of tumor cells survived much longer. About 50% of the mice remained alive and were killed on day 95. They revealed histologically no malignant lesion of the pleura except for residual changes of inflammatory reactions.     

Some peculiarities of the glucoregulatory response to glucose infusion in the rat

The glucoregulatory response to the i.v. infusion of different doses of glucose and glucose plus insulin was studied in anesthetized rats by using the primed constant infusion of glucose-2-3H. Infusion of glucose at the rate of 10 mg/kg/min induced a rise of about 100% in blood glucose, while the hepatic release of glucose showed only a small and transient decrease. A proportional increase of glycemia and glucose utilization (Rd) was observed without any appreciable change in the metabolic clearance rate (MCR) of glucose; a two-fold increase in plasma insulin was recorded at all times. In the group of rats receiving 20 mg/kg/min of glucose, changes in the above parameters were slightly greater; MCR showed a moderate increment in spite of the six-fold rise of plasma insulin. Finally, the influsion of large doses of insulin together with 20 mg/kg/min of glucose resulted in complete cessation of glucose release by the liver and in a remarkable increase of Rd and MCR. These results suggest a poor adaptability of the glucoregulatory system of the rat in response to glucose infusion as compared to other mammalian species.     

Suppression of the granulocyte colony-stimulating factor response to Escherichia coli challenge by alcohol intoxication

Alcohol's suppressive effects on polymorphonuclear leukocyte (PMN) production and function increases host susceptibility to a wide variety of infections and impairs the ability of these effector cells to seek and destroy invading pathogens. Granulocyte colony-stimulating factor (G-CSF), an important regulator of PMN production and function, is known to be increased in the plasma during infectious episodes. In previous studies we found acute alcohol intoxication to suppress the tumor necrosis factor-alpha (TNF alpha) response to in vivo challenges with bacteria or lipopolysaccharide. The present study was initiated to determine the impact of alcohol intoxication on the plasma G-CSF response to gram-negative infection. For this purpose, rats received an intravenous challenge of Escherichia coli (10(6) CFU) 30 min after an intraperitoneal injection of ethanol (5.5 g/kg) or an equivalent volume of saline (control). Ethanol-intoxicated rats had a greater 48 hr mortality to live E. coli injection than did unintoxicated animals (45% vs. 8%). Despite an increased bacterial burden in both the lung and liver at 24 hr after initiating E. coli infection in alcohol-intoxicated animals, PMN tissue recruitment, indexed as myeloperoxidase activity, did not differ between control and alcohol-treated rats. Moreover, alcohol suppressed blood PMN phagocytic capacity to a greater extent in animals given alcohol than controls at 5 and 24 hr after initiating infection. In control animals after intravenous E. coli injection, bioactive G-CSF increased in plasma and peaked near 300 ng/ml at 8 hr. In rats pretreated with alcohol, the plasma G-CSF response was markedly suppressed in response to intravenous E. coli (p < 0.05). In a second experiment, neutralization of the E. coli-induced plasma TNF alpha response by pretreatment with anti-TNF alpha antibody similarly inhibited the plasma G-CSF response. These results support the postulate that alcohol-induced inhibition of TNF alpha directly contributes to the adverse effects of alcohol on PMN function by suppressing the normal autocrine amplification pathway responsible for G-CSF production.