Neutrophil-endothelial cell interactions on endothelial monolayers grown on micropore filters.

We have developed a technique for growing endothelial monolayers on micropore filters. These monolayers demonstrate confluence by phase and electron microscopy and provide a functional barrier to passage of radiolabeled albumin. Neutrophils readily penetrate the monolayer in response to chemotaxin, whereas there is little movement in the absence of chemotaxin. This system offers unique advantages over available chemotaxis assays and may have wider applications in the study of endothelial function.

Airway complications from free-basing cocaine.

The majority of the deaths due to fires result from smoke inhalation, hypoxia, and systemic toxicity. Lower airway injury from chemical byproducts carried in the smoke is less frequent and thermal injury to the lower airways is a rare occurrence. We report a case of severe thermal injury to the conducting airways due to either inhalational injury or to intratracheal ignition of the ether vehicle used in free-basing cocaine resulting in severe reactive airways disease and tracheal stenosis requiring reconstructive surgery.

Melanotic malignant schwannoma of the right atrium.

A melanotic malignant schwannoma of the right atrium occurring in a 14-year-old girl is described. No previous such tumors in this location have been reported.

Two-dimensional echocardiographic detection of left pulmonary artery aneurysm following Potts' anastomosis.

The two-dimensional echocardiographic detection of left pulmonary artery aneurysm following a Pott's anastomosis in a patient with tetralogy of Fallot is described. The diagnosis was confirmed at angiography and surgery.

Bilateral uveal effusion associated with scleral thickening due to amyloidosis.

A 45-year-old man with primary systemic amyloidosis was found to have bilateral uveal effusions secondary to thickened sclera according to magnetic resonance imaging of the orbits. The patient was treated with bilateral sclerectomies and vortex vein decompression, and had an excellent outcome. Light microscopy of excised sclera revealed severe infiltration of the tissue by amyloid. To our knowledge, this is the first report of amyloid infiltration of the sclera leading to uveal effusion. Arch Ophthalmol. 2000;118:1293-1295

Effect of nicotine and acetylcholine on crustacean muscle membrane potential.

We have investigated the effect of nicotine and acetylcholine on the resting membrane potential of the crayfish extensor muscle in order to determine whether crustacean muscle can be activated by cholinergic compounds. Intracellular recordings from individual deep extensor abdominal muscle cells were made using standard glass microelectrode techniques. The resting membrane potential was measured before and after treatment with glutamate, nicotine, and acetylcholine. Glutamate, which is a known activator of crayfish muscle, was used to determine whether the muscle cell preparation was viable and capable of responding to any of the test substances. Our results confirm that application of glutamate is associated with a depolarization of the muscle membrane. However, muscle cells showed no depolarization after treatment with nicotine (50 microM) or acetylcholine (66 microM). These results argue against the notion that increases in muscle tension may be responsible for the increased receptor organ discharge observed in the presence of nicotine. Rather, it supports the hypothesis that nicotine is acting directly on the mechanoreceptor membrane to change its sensitivity.

Chemosensitivity of crayfish slowly adapting stretch receptors to nicotine.

It has recently been demonstrated that slowly adapting stretch receptors (SASRs) in the airways of the dog respond directly to nicotine (Federation Proc. 43: 318, 1984). The purpose of the present experiment was to investigate this chemical effect on an isolated stretch receptor. The crayfish muscle receptor organ was chosen, since crayfish muscle is reported to be insensitive to nicotine or acetylcholine and therefore permits the testing of any direct chemical effect of nicotine on the muscle stretch receptors. The tail was removed and pinned out in a tissue bath, and a stretch receptor organ was surgically isolated. Single-unit SASR extracellular nerve recordings were made while simultaneously measuring tension in the tail. Drugs were prepared in Van Harreveld's solution and administered into the bath kept at 18 degrees C. When resting muscle tension was essentially reduced to zero by cutting both ends of the receptor organ muscle, nicotine (0.07 microM) added to the bath increased receptor activity fourfold. This response was abolished by treatment with hexamethonium (690 microM). In a second group of animals in which the muscle was left intact, nicotine was shown to significantly increase receptor sensitivity to step changes in muscle tension. Once again hexamethonium blocked the response to nicotine. These results demonstrate that the sensitivity of mechanoreceptor can be altered by chemical interaction with nicotinic receptors, which dramatically alter sensory receptor activity.

Respiratory load compensation. II. Role of the cerebellum.

Effects of inspiratory tracheal occlusion (TO) on respiratory duration (inspiratory and expiratory duration), ventilation, and the peak integrated diaphragm electromyographic (integral of EMGdi) response were tested in 16 anesthetized cats before and after decerebellation with and without vagal input. The same protocols were repeated in the decerebrate preparation. Decerebellation did not significantly affect the baseline or the loaded values [tracheal occlusion (TO)] for respiratory duration, tidal volume, or magnitude of the integral of EMGdi response. Vagal blockade eliminated the load-compensating responses in the intact and the decerebrate preparation. However, vagal blockade in concert with decerebellation resulted in a significant (P < 0.05) reversible inhibition of the peak integral of EMGdi response during inspiratory TO. This suggests that removal of vagal and cerebellar influences during loaded breathing unmasked inhibitory inputs to the respiratory pattern generator. With vagus intact, decerebellation before or after decerebration abolished the attenuation of the peak integral of EMGdi response to TO observed with decerebration alone. We conclude that the cerebellum does play a role in determining the pattern of the respiratory response to TO. This influence may be direct and/or indirect via interaction with information emanating from suprapontine, vagal, and nonvagal sources.

Respiratory load compensation. III. Role of spinal cord afferents.

In a previous study, we reported that inspiratory tracheal occlusion (TO) significantly inhibited the motor drive to the diaphragm in a decerebellated bilaterally vagotomized preparation (J. Appl. Physiol. 75:675-681, 1993). The hypothesis to be tested in the present study was that respiratory muscle afferents activated by inspiratory TO provided the inputs responsible for the observed inhibition. Adult cats were anesthetized, tracheotomized, and instrumented with diaphragm electromyographic (EMGdi) recording electrodes. The cerebellum, vagi, and dorsal spinal cord (C2-T2) were surgically exposed. Inspiratory TO was applied before and after cold blockade of the dorsal cord (C6) or dorsal root (C3-6) transection in the intact and decerebellated vagotomized cat. Respiratory timing (inspiratory and expiratory duration) was determined from the EMGdi record, and the peak integrated EMGdi (integral of EMGdi) response was used as an index of respiratory motor drive. Our results showed that 1) cold blockade at the dorsal C6 level in an intact preparation significantly increased the peak of the integral of EMGdi response to TO and was reversible upon rewarming; 2) as previously reported, decerebellation coupled with bilateral vagotomy significantly decreased the peak integral of EMGdi response to TO with no effect on timing; 3) cold blockade (-1 degree C) of the dorsal cord at C6 significantly attenuated this inhibition, and subsequent dorsal rhizotomy at C3-6 completely abolished this inhibition; and 4) decerebellation, cold blockade of the dorsal cord (C6), and dorsal rhizotomy (C3-6) did not significantly affect baseline values in bilaterally vagotomized cats.(ABSTRACT TRUNCATED AT 250 WORDS)

Respiratory load compensation. I. Role of the cerebrum.

This study examines the extent to which the cerebrum and other suprapontine structures modulate the respiratory response to added mechanical resistive loads to breathing. Nine adult cats were anesthetized with thiopental sodium, tracheotomized, and instrumented with diaphragm electromyographic (EMGdi) recording electrodes. Two levels of resistive loads and tracheal occlusion were applied at the onset of inspiration in random order before and after decerebration. The integrated signal of the EMGdi (integral of EMGdi) was used to detect changes in respiratory timing and as an index of respiratory motor drive. The results showed that, compared with intact cats, decerebration did not significantly change baseline values for peak integral of EMGdi, respiratory timing, systemic blood pressure, or arterial blood gases. Although the percent changes in the peak integral of EMGdi elicited by the added loads were still significantly greater than those elicited by unloaded control breaths after decerebration, the magnitude of the responses was significantly attenuated at all load levels compared with the intact preparation. It is concluded that the cerebrum and/or other suprapontine structures provide information that is facilitatory to the respiratory pattern generator with little effect on timing.

Auxotrophy of Pseudomonas aeruginosa in cystic fibrosis.

Seventy-four of 403 (18.4%) sputum isolates of Pseudomonas aeruginosa from 49 of 136 (36.0%) adults with cystic fibrosis (CF) were auxotrophic mutants. Two of 11 (18.2%) isolates of P. aeruginosa taken from patients with non-CF bronchiectasis were also auxotrophic. All 99 strains taken from non-bronchiectatic sources were prototrophic. Forty-six of 55 (83.6%) CF auxotrophs required one or more of 36 growth factors tested; the requirements for the remaining 9 isolates were not identified. Methionine was the sole factor required by 17 of 22 (77.3%) isolated which depended on a single factor. We conclude that auxotrophy is a feature of P. aeruginosa infection in cystic fibrosis.

Transcoronary platelet activation and consumption in coronary artery disease: studies at rest.

The platelet count(PC), plasma platelet factor 4 (PF4) and plasma beta-thromboglobulin(beta TG) have been measured in blood obtained from a peripheral vein, the aortic root and the coronary sinus in 7 patients with normal coronary arteries, 9 patients with lesser degrees of coronary artery disease(CAD) and in 13 patients with severe CAD under resting conditions. In each patient group values obtained in the peripheral venous blood were similar to those obtained in normal subjects. In each group values obtained in blood from the coronary sinus were similar to those obtained in blood from the coronary aortic root and in most instances these were similar to values obtained in peripheral venous blood. for example, in the 13 subjects with hemodynamically significant 3-vessel or 2-vessel CAD the mean values in blood from a peripheral vein, the aorta and the coronary sinus respectively were: PC-194, 205, and 208 x 10(9)/1; PF4-3.3, 3.7, and 3.5 ng/ml; and beta TG-15.5, 23.0 and 18.6 ng/ml. These findings provide no support for the occurrence of continuous platelet activation or platelet consumption in the coronary vessels or elsewhere in patients with stable CAD, under resting conditions, regardless of its severity.

Platelet activation caused by cardiac catheter blood collection, and its prevention.

The study of platelet changes occurring across the coronary circulation is important in the investigation of the platelet's role in ischemic heart disease. It requires blood sampling through cardiac catheters. This could activate platelets and alter the results of tests of platelet activation and reactivity. This study was designed to examine this problem and to devise satisfactory methods for obtaining blood for platelet studies through long catheters. Blood collected through catheters introduced with a guide-wire had a much higher plasma heparin neutralising activity (HNA), platelet factor 4(PF4) and beta-thromboglobulin (beta TG) than peripheral venous blood, and lower platelet count(PC). Blood collected through catheters introduced via a sheath, and kept filled with anticoagulant/antiplatelet solution until blood sampling, gave results similar to peripheral venous blood for the PC, platelet aggregate ratio, platelet fluorescent granule count, and for plasma HNA, PF4 and beta TG. It is concluded that platelets are activated during blood collection through cardiac catheters; however, with appropriate precautions, blood which is satisfactory for platelet studies can be obtained.

Pseudomonas cepacia pulmonary infection in adults with cystic fibrosis: is nosocomial acquisition occurring?

Ribotyping of 25 isolates of Pseudomonas cepacia taken from the sputum of 21 adults with cystic fibrosis (CF) who were registered at the Royal Brompton Hospital between 1987 and 1991, revealed that seven patients (33.3%) shared strains of a similar ribotype pattern with others, while 14 patients (63.7%) harboured strains unique to each individual. Constancy of sputum strain carriage was seen in two of three patients sampled twice over a 3-month period. Although no evidence for patient-to-patient transmission of P. cepacia within this group of patients was found, the fact that one third of CF patients shared strains of the same ribotype with others, suggests that nosocomial acquisition of this organism may have occurred.

Cystic fibrosis: antibiotic prescribing practices in the United Kingdom and Eire.

The antimicrobial prescribing practices of 26 physicians from the U.K. and Eire who care for patients with cystic fibrosis (CF) were assessed by postal questionnaire. Our main aim was to delineate divergent practices which may reveal a need for controlled prospective studies. For first-line intravenous (i.v.) therapy of acute exacerbations associated with Pseudomonas aeruginosa, 20 physicians (76.9%) combine a penicillin derivative with an aminoglycoside, in contrast to five (19.2%) who regularly use i.v. monotherapy with ceftazidime and one who combines i.v. ceftazidime with an aminoglycoside. When i.v. therapy is considered inappropriate, oral ciprofloxacin is sometimes used by all clinicians and oral broad spectrum agents are used in addition by 13, chloramphenicol being prescribed most often. Excluding allergy, the most important factor influencing choice of agents by 19 (73.1%) physicians is the most recent sputum susceptibility results. For maintenance therapy, 21 prescribe oral anti-staphylococcal agents if Staphylococcus aureus is isolated; of these, eight do so only if lung function deteriorates, nine after repeated isolation and four after first isolation of S. aureus. The remaining five physicians give anti-staphylococcal drugs to all patients once the diagnosis of CF is made. For maintenance of lung function in patients with persistent P. aeruginosa, all physicians used nebulized antibiotics, the indications for which vary between units. There was general concordance in the therapy of exacerbations associated with P. aeruginosa, whereas the use of agents to maintain lung function is more varied. We suggest that prospective studies address practices which vary greatly, such as the route, the duration and the timing of initiating antibiotic therapy given to maintain lung function.

Pseudomonas cepacia: pulmonary infection in patients with cystic fibrosis.

This retrospective study reviews the patterns of P. cepacia pulmonary infection in 75 of a total of 872 mainly adults with cystic fibrosis, registered here during the 4 years 1987-1990; 35 (47%) were female. During this period, 55 patients acquired P. cepacia and the annual incidence and prevalence rates have remained between 1.6 and 3.1%, and 4.1 and 5.9%, respectively. The mean age at the time of the first isolation of P. cepacia was 23 years, ranging 11-45 years. Sixty-eight percent of the initial isolates were multi-resistant (sensitive to fewer than three of 15 anti-pseudomonal agents). Prior to acquisition of P. cepacia, 28 (50.9%) patients already had severe lung disease and only three had normal lung function. Infection was transient in 39.1% of patients. Initial multi-resistance of P. cepacia to anti-pseudomonal agents was significantly associated with persistent infection. Clinical outcome was unaffected by age, sex and early intravenous antibiotic therapy but was significantly adversely affected by increasing severity of lung disease at the onset of P. cepacia infection and by initial multi-resistance, and persistence of the organism. Thus, all patients with normal or mild lung disease at the outset of infection have remained clinically stable, whereas, only six of 28 patients with severe disease remained stable, three of whom were transiently infected with P. cepacia. The prevalence of P. cepacia at the time of death fluctuated between 12.5% and 26.9% during the study period.

The management of children born to human immunodeficiency virus seropositive women.

Increasing numbers of children born to human immunodeficiency virus (HIV) antibody-positive women are being identified, but guidelines as to their management are lacking. We have therefore established a paediatric counselling and screening clinic for managing such children in Edinburgh. During a period of 3 years, 49 infants and children of 43 HIV seropositive women have been seen. After a median follow-up period of 23 months, four children were found to have clinical evidence of HIV disease which was non-specific and could have been missed had they not been regularly monitored. Thus, close surveillance of infants born to seropositive women is important. Identifying a single clinic where this is done has allowed experience to accumulate on issues beyond the medical management of these infants as well as contributing to the clinical care of infants with symptoms. Based on this experience, we have developed guidelines for managing children born to HIV antibody-positive women.

Long-term outcome of gold eyelid weights in patients with facial nerve palsy.

OBJECTIVE: To assess the safety and efficacy of upper eyelid gold weight implants in managing paralytic lagophthalmos and to compare two surgical techniques for their insertion. STUDY DESIGN: Retrospective case series. SETTING: Tertiary referral center. PATIENTS: One hundred four patients had a gold weight implanted for paralytic lagophthalmos between 1982 and 1996 at the Royal Prince Alfred Hospital in Sydney. Each patient had more than 2 years of follow-up of lid load function. MAIN OUTCOME MEASURES: The effectiveness of gold weights in reanimating eyelid closure, mean duration of gold weight retention, reasons for removal, and complications resulting from a gold weight; these outcomes were also compared using two surgical techniques for gold weight insertion. RESULTS: One hundred three patients maintained corneal integrity. At the time of assessment, 46 patients had had their lid loads removed from their eyelids, and 58 lid loads remained in situ. Of the lid loads that were removed, 78% were because the facial nerve had recovered. The remaining 22% were removed because of cosmetic dissatisfaction (7 patients), the lid load becoming too superficial (6 patients), migration (3 patients), partial extrusion (1 patient), and ptosis resulting from too heavy a weight (1 patient). CONCLUSION: Gold weights are well tolerated and effective in managing paralytic lagophthalmos. An open surgical technique with direct suture fixation of the gold weight to the tarsal plate produced fewer complications than inserting the lid load into a prefashioned tissue pocket in the preseptal space through a small lateral skin incision.

Application of enzyme-linked immunosorbent assay for detecting antibody to Mycoplasma gallisepticum infections in poultry.

An enzyme-linked immunosorbent assay (MYCO-ELISA) was developed to detect antibodies to Mycoplasma gallisepticum (MG) in chicken sera. The assay was standardized in terms of optimum antigen concentration, serum dilution, conjugate dilution and incubation temperature, and time. The MYCO-ELISA antigen was prepared from MG whole bacterial cell or its disrupted cell suspension. Both preparations showed strong affinity for binding or adsorbing to the surface of polystyrene wells of the microtiter plate. The MYCO-ELISA was more sensitive than the hemagglutination-inhibition test. However, cross-reactions were observed with sera from M. synoviae (MS)-infected birds.

Dose-titration to confirm the level of fenbendazole for control of Raillietina cesticillus in broiler chickens.

A total of 452 broiler chickens, naturally infected with Raillietina cesticillus, were allotted into six treatment groups. One group was fed unmedicated broiler ration (Group 1), and the other five groups were fed broiler ration containing fenbendazole at 180 ppm for 3 days (38.5 mg/kg body weight [BW]), 240 ppm for 3 days (50.9 mg/kg BW), 120 ppm for 6 days (52.2 mg/kg BW), 180 ppm for 6 days (79.9 mg/kg BW), or 240 ppm for 6 days (104.3 mg/kg BW). Fenbendazole was 100.0% efficacious against R. cesticillus when administered in the diet at 240 ppm for 6 days; 99.9% at 240 ppm for 3 days and at 180 ppm for 6 days; 99.5% at 120 ppm for 6 days; and 96.9% at 180 ppm for 3 days. Fenbendazole treatment had no adverse effect on weight gain or feed intake.