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Biomedical subjects

J V Collins

Publications and source records attributed to J V Collins.

At least 19 recordsLinked to original sources
PubMed1992

A study of glutaraldehyde disinfection of fibreoptic bronchoscopes experimentally contaminated with Mycobacterium tuberculosis.

Mycobacteria are difficult to inactivate, and concern about the spread of tuberculosis at bronchoscopy has a major influence on infection control practices. Recommendations from the UK Department of Health are based largely on in-vitro mycobactericidal assays which do not take into account the particular conditions encountered in endoscopy units. In this applied study cleaning and disinfection methods were examined using five bronchoscopes that were heavily contaminated with a recent isolate of Mycobacterium tuberculosis in sputum. Cleaning reduced contamination by a mean 3.5 log(10) colony forming units (cfu) per ml; all bronchoscopes were free of detectable mycobacteria after 10 min in 2% alkaline glutaraldehyde (AG). It is recommended that all bronchoscopes be thoroughly pre-cleaned and disinfected in 2% AG for 20 min as part of a uniform policy of infection control.

Bronchoscopes↗
PubMed1992

Comparison of DNA amplification and immunofluorescence for detecting Pneumocystis carinii in patients receiving immunosuppressive therapy.

Two studies were performed to compare the sensitivity of DNA amplification with immunofluorescence for the detection of Pneumocystis carinii in asymptomatic normal and immunosuppressed subjects receiving no anti-Pneumocystis chemoprophylaxis. In the first study, immunofluorescence and silver stains were used to examine 12 induced sputa and 12 bronchoalveolar lavage specimens from 24 normal control subjects; induced sputa from 20 renal transplant recipients; and induced sputa from 11 patients with fibrosing alveolitis. All specimens were negative for P carinii using both stains, apart from one renal patient in whom 2 P carinii cysts were seen by immunofluorescence alone. In the second study, DNA amplification and immunofluorescence were used to examine induced sputa from 3 groups of 10 control, renal, and heart/lung transplant recipients. All 30 specimens were negative for P carinii by immunofluorescence. However, 3 renal and 2 heart/lung patients were positive for P carinii by DNA amplification alone. One of these patients developed P carinii pneumonia 6 weeks after sputum induction. DNA amplification is a more sensitive technique than immunofluorescence for detecting P carinii. P carinii colonization occurs in asymptomatic organ transplant recipients, but not in normal individuals.

Adult↗
PubMed1992

Symptomatic cysts in otherwise normal lungs of children and adults.

The clinical and pathological features of 28 lung cysts resected in the period 1980-1989, excluding those from patients with emphysema elsewhere in their lungs, have been reviewed. In 12 children aged 8 days to 17 years, five cysts were congenital adenomatoid malformations, three were bronchogenic cysts, two were intralobar sequestrations, one was a cystic haemangioma and one resembled the cysts excised from 16 adult patients. This latter group ranged in age from 20 to 62 years and included 11 cigarette smokers and five asthmatics. Twelve of these cysts were intralobar and four were attached by a pedicle to the pleural surface of the lung. All these cysts had a fibromuscular wall showing varying degrees of acute and chronic inflammation. The presence of at least a partial lining of epithelial cells in all the cysts was confirmed using an immunocytochemical marker. The surrounding lung did not show any significant pathology. These cysts are labelled as simple fibromuscular pulmonary cysts. In the childhood cases, a congenital cause could be established in the majority. The pathogenesis of the adult cysts remains unclear. The presence of inflammation in the cyst walls does not necessarily suggest a role for infection, as secondary infection of cysts cannot be ruled out. An aetiological role for local damage due to cigarette smoking or asthma must be taken into consideration.

Adolescent↗
PubMed1991

Eosinophils, T-lymphocytes, mast cells, neutrophils, and macrophages in bronchial biopsy specimens from atopic subjects with asthma: comparison with biopsy specimens from atopic subjects without asthma and normal control subjects and relationship to bronchial hyperresponsiveness.

Bronchial biopsy specimens were obtained by fiberoptic bronchoscopy from 21 atopic subjects with asthma, 10 atopic subjects without asthma, and 12 normal healthy control subjects. With immunohistochemical techniques and a panel of monoclonal antibodies, inflammatory cells were identified and counted in the bronchial mucosa. The mean number of leukocytes (CD45+) and T-lymphocytes (CD3+, CD4+, and CD8+) at two airway levels in the subjects with asthma tended to be higher than in the other groups, but this difference did not achieve statistical significance. Similarly, there were no significant differences in the numbers of mucosal-type or connective tissue-type mast cells, elastase-positive neutrophils, or Leu-M3+ cells in the airway mucosa of subjects with asthma compared with atopic subjects without asthma and healthy control subjects. In contrast, significantly more interleukin-2 receptor-positive (CD25+) cells and "activated" (EG2+) eosinophils (EOSs) were present in the airways of subjects with asthma at both proximal and subsegmental biopsy sites. When the relationships between numbers of T-lymphocytes, activated (CD25+) cells, and EOSs were analyzed, there were positive correlations between CD3 and EG2, between CD3 and CD25, and between CD25 and EG2 positive cells in the airways of subjects with asthma. Furthermore, the ratio of EG2+ to CD45+ cells correlated with the provocative concentration of methacholine that caused a 20% decrease of FEV1 in hyperresponsive subjects. Although these associations do not prove a causal relationship, the results support the hypothesis that activated (CD25) T-lymphocytes release products which regulate recruitment of EOSs into the airway wall. In addition, our findings suggest that, in the large airways at least, asthma is not associated with hyperplasia of either mucosal-type or connective tissue-type mast cell.

Adult↗
PubMed1991

Viral transmission and fibreoptic endoscopy.

Fibreoptic endoscopes have been responsible for outbreaks of infection with bacteria although viral transmission has been reported only once. The emergence of human immunodeficiency virus (HIV) has prompted a review of infection control practices in endoscopy units because of the theoretical possibility that HIV might be transmitted at endoscopy. Recent studies have shown that bronchoscopes and gastroscopes used on AIDS patients become contaminated with HIV genetic material although cleaning equipment in detergent removes all traces of the virus. Thorough precleaning has been shown to eliminate even high titres of HIV from endoscopes and 2% alkaline glutaraldehyde has been found to inactivate the virus rapidly even if the virus is dried in serum to a surface. These findings support the British Society of Gastroenterology recommendations for the cleaning and disinfection of endoscopic equipment and demonstrate that a uniform policy of infection control is practicable in endoscopy units.

DNA, Viral↗
PubMed1991

Steroid trials in the assessment of reversibility of air flow limitation: a survey of current clinical practice of chest physicians.

To evaluate how steroid trials are currently used in the assessment of reversibility of air flow limitation, a postal questionnaire was sent to 355 consultant members of the British Thoracic Society working in England and Wales; 253 questionnaires were returned (71% response rate). Two respondents did not undertake steroid trials; of the remaining 251, 75% prescribed 30-40 mg oral prednisolone, with the commonest treatment period being 2 weeks. A high dose steroid inhaler was sometimes used as an alternative by 31% of respondents. Although 71% of respondents made lung function measurements on several occasions before starting steroids and 76% made measurements during treatment, 78% assessed patients on only one occasion at the end of the trials to ascertain its outcome. Weight, blood pressure and glycosuria were measured less frequently after the steroid treatment compared to the pre-trial period. Blood glucose and serum electrolytes were infrequently measured both before and after treatment. Wide variations exist in steroid trial regimens and current practice may neither provide definitive evidence of treatment benefit nor an adequate safeguard for patients against potential side-effects.

Chronic Disease↗
PubMed1991

A comparison of several agents with two delivery systems for the prevention of airway narrowing induced by nebulised pentamidine isethionate.

Bronchial narrowing is the major side effect of inhaled nebulised pentamidine isethionate, used for the prophylaxis and treatment of Pneumocystis carinii pneumonia. Several agents and delivery systems were assessed for prophylaxis of bronchial narrowing in HIV-positive males receiving regular nebulised pentamidine isethionate. In a previous study we found the mean maximum fall in FEV1 with nebulised pentamidine alone to be 21%. FEV1 was measured before and after inhaling nebulised pentamidine, preceded by one of the following bronchodilator/immunoregulatory agents: Terbutaline metered dose inhaler (500 micrograms), nebulised salbutamol (5 mg), nebulised ipratropium bromide (500 micrograms), nebulised sodium cromoglycate (20 mg), and nedocromil sodium metered dose inhaler (4 mg). Each agent was administered once only to ten different subjects. Nebulised salbutamol gave most effective prophylaxis against bronchial narrowing induced by nebulised pentamidine (mean maximum fall in FEV1 = 5% vs. 21%, P less than 0.001). Terbutaline given by metered dose inhaler was significantly less effective than high dose terbutaline (10 mg) given by nebuliser, demonstrated in the previous study (mean maximum fall in FEV1 = 14% vs. 6%, P less than 0.05). Mean maximum falls in FEV1 for ipratropium bromide, sodium cromoglycate and nedocromil sodium were 16, 17 and 16%, respectively. High dose beta 2-agonists administered by nebuliser give more effective prophylaxis against nebulised pentamidine-induced bronchial narrowing than either lower doses given by metered dose inhaler, anticholinergics or immunoregulatory drugs.

Adult↗
PubMed1991

Effect of terbutaline on bronchoconstriction induced by nebulised pentamidine.

The severity, duration, and reversibility of pentamidine induced bronchial narrowing was studied with and without pretreatment with nebulised terbutaline 10 mg in an open study of 40 patients seropositive for the human immunodeficiency virus (HIV). All subjects received pentamidine 300 mg in 5 ml water via an Acorn System 22 jet nebuliser. The forced expiratory volume in one second (FEV1) fell in all 20 patients given pentamidine alone, the mean maximum fall being 20.6%. In the 20 patients given pentamidine preceded by nebulised terbutaline the mean maximum fall in FEV1 was 4%; three subjects had a fall in FEV1 of more than 10%.

Administration, Inhalation↗
PubMed1991

Recovery of the human immunodeficiency virus from fibreoptic bronchoscopes.

Ten bronchoscopes that had been used on patients with the acquired immunodeficiency syndrome were sampled to determine the nature and extent of microbial contamination. Samples were taken by irrigating the suction biopsy channel with modified viral transport medium and by swabbing the insertion tube. Sampling was repeated after they had been cleaned in detergent and after two minutes' disinfection in 2% alkaline glutaraldehyde. Before being cleaned the seven bronchoscopes tested by polymerase chain reaction were contaminated with the human immunodeficiency virus, though infectivity and antigen assays gave negative results. Other organisms identified were hepatitis B virus (1), commensal bacteria (9), and Pneumocystis carinii (4). Mean bacterial contamination was 2.27 log colony forming organisms per millilitre. Cleaning the bronchoscope before disinfection removed all detectable contaminants with a reduction in bacterial growth of up to 8 log colony forming units/ml.

Bronchoscopes↗
PubMed1991

Interleukin-5 mRNA in mucosal bronchial biopsies from asthmatic subjects.

Using in situ hybridization, we have investigated the expression of interleukin-5 (IL-5) mRNA in bronchial biopsies from asthmatics (n = 10) and controls (n = 9). The number of IL-5-nRNA-positive cells were compared with the number of CD25+ and EG2+ cells and total eosinophil counts. Specific hybridization signals for IL-5 mRNA were demonstrated in 6 out of the 10 asthmatic subjects but in none of the controls. The 6 IL-5-mRNA-positive asthmatics tended to have more severe disease and showed a significant increase in the degree of infiltration of the bronchial mucosa by activated T lymphocytes and eosinophils.

Asthma↗
PubMed1991

Expression of mRNA for interleukin-5 in mucosal bronchial biopsies from asthma.

We have attempted to identify mRNA for IL-5 in endobronchial mucosal biopsies from asthmatics and controls, using the technique of in situ hybridization. Bronchial biopsies were obtained from 10 asthmatics and 9 nonatopic normal controls. A radio-labeled cRNA probe was prepared from an IL-5 cDNA and hybridized to permeabilized sections. These were washed extensively before processing for autoradiography. An IL-5-producing T cell clone derived from a patient with the hyper-IgE syndrome was used as a positive control. As a negative control, sections were also treated with a "sense" IL-5 probe. Specific hybridization signals for IL-5 mRNA were demonstrated within the bronchial mucosa in 6 out of the 10 asthmatic subjects. Cells exhibiting hybridization signals were located beneath the epithelial basement membrane. In contrast, there was no hybridization in the control group. No hybridization was observed with the sense probe. The six IL-5 mRNA-positive asthmatics tended to have more severe disease than the negative asthmatics, as assessed by symptoms and lung function, and showed a significant increase in the degree of infiltration of the bronchial mucosa by secreting (EG2+) eosinophils and activated (CD25+) T lymphocytes. Within the subjects who showed positive IL-5 mRNA, there was a correlation between IL-5 mRNA expression and the number of CD25+ and EG2+ cells and total eosinophil count. This study provides evidence for the cellular localization of IL-5 mRNA in the bronchial mucosa of asthmatics and supports the concept that this cytokine regulates eosinophil function in bronchial asthma.

Adult↗
PubMed1990

Elimination of high titre HIV from fibreoptic endoscopes.

Concern about contamination of fibreoptic endoscopes with human immunodeficiency virus (HIV) has generated a variety of disruptive and possibly unnecessary infection control practices in endoscopy units. Current recommendations on the cleaning and disinfection of endoscopes have been formulated without applied experimental evidence of the effective removal of HIV from endoscopes. To study the kinetics of elimination of HIV from endoscope surfaces, we artificially contaminated the suction-biopsy channels of five Olympus GIF XQ20 endoscopes with high titre HIV in serum. The air and water channels of two instruments were similarly contaminated. Contamination was measured by irrigating channels with viral culture medium and collecting 3 ml at the distal end for antigen immunoassay. Endoscopes were then cleaned manually in neutral detergent according to the manufacturer's recommendations and disinfected in 2% alkaline glutaraldehyde (Cidex, Surgikos) for two, four, and ten minutes. Contamination with HIV antigens was measured before and after cleaning and after each period of disinfection. Initial contamination comprised 4.8 x 10(4) to 3.5 x 10(6) pg HIV antigen/ml. Cleaning in detergent achieved a reduction to 165 pg/ml (99.93%) on one endoscope and to undetectable levels (100%) on four. After two minutes in alkaline glutaraldehyde all samples were negative and remained negative after the longer disinfection times. Air and water channels, where contaminated, were tested after 10 minutes' disinfection and were negative. These findings underline the importance of cleaning in removing HIV from endoscope and indicate that the use of dedicated equipment and long disinfection times are unnecessary.

Acquired Immunodeficiency Syndrome↗
PubMed1990

Effects of inhaled PAF in humans on circulating and bronchoalveolar lavage fluid neutrophils. Relationship to bronchoconstriction and changes in airway responsiveness.

We have compared the effect of inhaled platelet activating factor (PAF) on circulating neutrophils with its ability to induce bronchoconstriction and bronchial hyperresponsiveness in humans. Human volunteers inhaled PAF, given as six successive inhalations 15 min apart, followed by bronchoalveolar lavage (BAL) 4 h later. The mean density and volume of circulating neutrophils were measured by metrizamide gradients and flow cytometry, respectively. PAF caused a decrease in Vp20 of 38.2 +/- 4.5% at 5 min after the first inhalation (p less than 0.001). This was associated with a fall in the peripheral blood neutrophil count from 3.15 +/- 0.3 to 1.1 +/- 0.3 x 10(6) per ml (p less than 0.001), followed by a rebound neutrophilia (p less than 0.01). The mean density of peripheral blood neutrophils fell significantly at 15 min (p less than 0.02), with a return to baseline values despite further PAF inhalations; this was associated with an increase in neutrophil volume (n = 4; p less than 0.05). The numbers of neutrophils (x 10(5] in BAL fluid after PAF were significantly greater than after inhalation of lyso-PAF: 7.1 +/- 1.4 (n = 7) versus 1.3 +/- 0.3 (n = 5, p less than 0.01); eosinophil counts did not change significantly. The PC40 (the concentration of methacholine needed to cause a fall in Vp30) decreased from 17.1 (GSEM 1.40) to 8.7 (1.44) mg/ml (n = 12, p less than 0.02) 3 days after PAF. Inhaled lyso-PAF was inactive in all these respects.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Inhalation↗