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Biomedical subjects

N T Bateman

Publications and source records attributed to N T Bateman.

At least 37 records · Page 2Linked to original sources
PubMed1991

Non-invasive management of fever and breathlessness in HIV positive patients.

In a prospective study of 72 human immunodeficiency virus (HIV) positive patients presenting with fever and breathlessness, a non-invasive management protocol, incorporating a scanning technique using radioactively labelled diethylenetriamine penta acetate (DTPA) and sputum induction, was found to be highly sensitive and specific in the early detection of Pneumocystis carinii pneumonia (PCP). At presentation, the DTPA scan was abnormal in 34 of 36 cases of PCP, irrespective of smoking history, whilst the chest radiograph was diffusely abnormal in 21 cases. Sputum induction identified 7 of 14 patients with PCP in the first six months of its use and 7 of 10 patients over the last six months. The DTPA lung scan and induced sputum examination are non-invasive techniques which can be used to investigate out-patients. In combination they detected all cases of PCP at presentation, reduced the need for bronchoscopy, resulted in a low case fatality (5.4%) and reduced the need for admission.

Acquired Immunodeficiency Syndrome↗
PubMed1990

Does inhalation of pentamidine in the supine position increase deposition in the upper part of the lung?

To assess the effect of posture on the distribution of nebulized pentamidine isethionate deposition in the lung, ten patients with AIDS were studied. Two nebulizer systems, System 22 Mizer (MedicAid) and Respirgard II (Marquest) were modified by adding 40 cm of corrugated tubing (volume 150 ml) to allow the patients to be studied in both the sitting and supine posture. Modification of the nebulizers caused a reduction in lung deposition in the sitting position for the System 22 Mizer but increased deposition in the Respirgard II compared with the unmodified apparatus. The ratio of upper to lower zone deposition (corrected for 133Xe distribution) was increased in the supine position for both devices (p less than 0.01). The best upper zone deposition was achieved with the unmodified System 22 Mizer in the sitting position. Respirgard II had the lowest nonpulmonary deposition and the lowest incidence of adverse effects. The supine position was associated with a redistribution of deposition to the upper zones. To attempt to reduce upper zone recurrence of Pneumocystis carinii pneumonia, the supine posture is suggested for less efficient nebulizer devices, ie, the Respirgard II, but for more efficient systems, ie, System 22 Mizer, the sitting position is probably suitable. This postulate needs to be confirmed by a clinical trial.

Acquired Immunodeficiency Syndrome↗
PubMed1989

The place of lung 99mTc DTPA aerosol transfer in the investigation of lung infections in HIV positive patients.

Pneumocystis carinii pneumonia (PCP) is the most common cause of pneumonia in HIV antibody positive patients, but other pneumonias remain important, i.e. streptococcal and mycobacterial infections. A definitive diagnosis relies on obtaining samples from the lung either noninvasively (induced sputum), or invasively (bronchoalveolar lavage, transbronchial or open lung biopsy). We have used the noninvasive technique of nebulized 99mTc DTPA transfer, to assess patients with PCP (n = 30) and other lung infections (n = 20) to see whether this test will distinguish between the various infections. The presence of a biphasic, rapid transfer curve indicates severe extensive alveolar damage and is seen in PCP or legionella pneumonia. The mean transfer time (T50 +/- SEM) for patients with PCP (whether smokers or nonsmokers) was 2.1 +/- 0.2 min, and for two of the patients with legionella 3.2 min. In PCP effective treatment causes the transfer to slow (mean T50 22.7 +/- 3.3 min, n = 24) and become monoexponential. Other causes of these changes in transfer are discussed. The other pneumonias (streptococcal, mycobacterial, and staphylococcal) did not result in biphasic curves or very rapid times, their T50 values are indistinguishable from cigarette smokers. In this patient group the DTPA transfer is a useful noninvasive investigation with a very rapid, biphasic curve indicating a high probability of PCP.

Adult↗
PubMed1989

The effect of noradrenaline on the ability of rat papillary muscle to resist an acute respiratory acidosis.

We have studied the effect of an increase in extracellular calcium and of noradrenaline on the ability of rat right ventricular papillary muscle in vitro to resist an acute fall in extracellular pH (pHe) produced by a rise in superfusate PCO2. We found a steep linear relationship, slope 0.86(SEM 0.06), r = 0.94, between a plot of logarithmic change in tension against pHe for control muscles (superfusate containing 1.8 mmol.litre-1 calcium). An increase in extracellular calcium (3.6 mmol.litre-1) increased absolute tension but did not alter the slope significantly. Increasing concentrations of noradrenaline (6.3 x 10(-8) to 6.3 x 10(-6) M) progressively reduced the slope of the tension/pHe plot from 0.82(0.05) to 0.35(0.07), p less than 0.001. Noradrenaline improved the ability of rat papillary muscle to resist an acute acidosis by a mechanism independent of changes in calcium concentration.

Acidosis, Respiratory↗
PubMed1989

Does 99Tcm human serum albumin alter the characteristics of nebulized pentamidine isethionate?

Nebulized pentamidine has been used as therapy for Pneumocystis carinii pneumonia. The lung dose delivered using different nebulizer systems and doses of pentamidine from 50-600 mg is unknown. To measure this a marker which does not alter the characteristics of the nebulized pentamidine solution must be found. We have assessed the aerosol characteristics of four jet nebulizers (System 22, System 22 Mizer, Optimist, Respigard II) and one ultrasonic device (Pulmosonic) using two concentrations of pentamidine isethionate (50 mg and 300 mg) in 3 ml of solution. The jet nebulizers were operated at a flow rate of 6 l min-1, a rate suitable for home use. These measurements were repeated with 99Tcm labelled human serum albumin (HSA) added to the solutions. A linear relationship between 99Tcm-HSA activity and pentamidine concentration was demonstrated by using a nine stage cascade impactor. The Respigard II and Optimist produced the best results in terms of particle size (96% less than 5 microns), but the addition of the tracer to the latter led to a smaller particle size range and a reduction in the amount of aerosol present at the mouthpiece. The Mizer system had 52% of particles less than 5 microns, the Pulmosonic 46%. The Respigard II had a total output of 8.7 mg for the 50 mg concentration and 30.9 mg for the 300 mg concentration. The System 22 produced corresponding outputs of 18.0 mg and 67.1 mg with 54% of the aerosol particles less than 5 microns.(ABSTRACT TRUNCATED AT 250 WORDS)

Aerosols↗
PubMed1989

Contractility of papillary muscle from rats exposed to 28 days of hypoxia, hypercapnia, and hypoxia with hypercapnia.

The effects of chronic respiratory failure (hypoxia and hypercapnia) on the contractile properties of cardiac muscle are not established. A study was performed of the isometric contractile properties of isolated papillary muscle removed from rats exposed in a normobaric environmental chamber to 28 days of hypoxia (fractional inspired oxygen (FIO2) 10%, fractional inspired carbon dioxide (FICO2) less than 1%), hypercapnia (FIO2 21%, FICO2 5%), and hypoxia with hypercapnia (FIO2 10%, FICO2 5%). Rats exposed to both hypoxia and hypoxia with hypercapnia developed selective right ventricular hypertrophy. Exposure to hypercapnia alone did not alter right ventricular weight. No change in right ventricular papillary muscle contractility per unit muscle mass was observed as measured by maximum active tension, maximum rate of rise or fall of tension, or time to peak tension. Rat cardiac muscle adapts successfully to the altered acid-base environment and increased work load associated with prolonged exposure to hypoxia and mild hypercapnia.

Animals↗
PubMed1988

Differences in relative efficiency of nebulisers for pentamidine administration.

The study compared the pulmonary deposition of nebulised pentamidine when inhaled by way of different nebuliser systems by nine human-immunodeficiency-virus-positive patients with a history of previous Pneumocystis carinii pneumonia. Pentamidine, 50 mg or 300 mg, mixed with technetium-99m-labelled human serum albumin in a total volume of 3 ml, was administered by way of three jet nebulisers (System 22', 'System 22 Mizer', and 'Respigard II') operated with a gas flow of 6 l/min, and one ultrasound nebuliser ('Pulmosonic'). Pulmonary and non-pulmonary isotope deposition was measured for each apparatus and adverse effects and lung function tests were recorded. For both doses of pentamidine, the system 22 mizer produced the largest pulmonary isotope deposition and it was completed in the shortest time. Oropharyngeal and gastric deposition were least with the respigard II, which also caused the fewest adverse effects. The adverse effects were greatest with the system 22 mizer and pulmosonic and the higher pentamidine dose, which also caused significant reductions in measurements of pulmonary function. It is concluded that either the system 22 mizer or the respigard II should be used to administer nebulised pentamidine.

Amidines↗
PubMed1988

Effect of amiloride on contractility of rat cardiac muscle exposed to chronic hypercapnia and acute acidosis.

Papillary muscle preparations from rats with normal arterial oxygen and carbon dioxide tensions and from rats which had been maintained with normal oxygen tension but with hypercapnia for 28 days (FICO2 = 5%) were subjected to acute hypercapnia with or without amiloride, a competitive inhibitor of the Na+/H+ pump. Acclimatisation to hypercapnia reduced the slope of the line relating log tension against the extracellular pH from 0.96(SEM0.06) to 0.71(0.07) (p less than 0.02). Amiloride increased the slope in unacclimatised muscle to 1.39(0.09), p less than 0.001 and in muscles acclimatised to hypercapnia to 1.03(0.13), p less than 0.05. The slope in acclimatised muscles was significantly less steep than in unacclimatised muscle (p less than 0.05). The sarcolemmal Na+H+ exchanger is important in the protection of rat cardiac muscle against acute respiratory acidosis.

Acidosis↗
PubMed1987

Alveolar permeability in HIV antibody positive patients with Pneumocystis carinii pneumonia.

Pulmonary permeability was assessed using the technique of 99mTc (technetium-99m) diethylene triamene pentacetic acid (DTPA) aerosol transfer in 10 patients who had antibodies to human immunodeficiency virus (HIV) and were non-smokers and in 20 HIV antibody positive smokers. Five patients had Pneumocystis carinii pneumonia (PCP) proved by transbronchial lung biopsy; four were non-smokers and one a smoker. Two findings emerged: patients with PCP had greater epithelial permeability than non-smokers and smokers; and the permeability curves were monophasic in smokers and non-smokers, but biphasic in patients with PCP. The biphasic curve observed is indicative of diffuse alveolar damage and might be useful to predict PCP in patients with antibodies to HIV who have normal chest radiographs. As the study was of only five patients with PCP, however, further studies are necessary to confirm this observation.

Adult↗
PubMed1987

The acute haemodynamic effects of intravenous verapamil in patients with chronic obstructive airways disease.

The haemodynamic effects of a single intravenous dose of verapamil have been investigated in patients with chronic obstructive airways disease both during an acute exacerbation and when in a stable clinical condition and compared with the effects of oxygen administered by nasal cannulae. In five patients studied during an episode of acute on chronic hypoxaemia (mean PaO2 = 5.4 kPa) there was a significant fall in pulmonary vascular resistance (p less than 0.03) following intravenous verapamil (10 mg) without any reduction in PaO2, cardiac index or oxygen delivery. Subsequent administration of oxygen by nasal cannulae at 2 l/min for 30 min produced similar pulmonary haemodynamic changes: pulmonary vascular resistance fell by 17 +/- 3 per cent following oxygen and by 22 +/- 4 per cent following verapamil. In a similar group of five patients in a stable clinical condition (mean PaO2 = 7.3 kPa) neither oxygen nor verapamil administered during acute exacerbations produced any significant changes in pulmonary vascular resistance, cardiac index or oxygen delivery.

Acute Disease↗
PubMed1986

Pulmonary permeability in hematologic malignancies. Effects of the disease and cytotoxic agents.

Pulmonary permeability was assessed using the technique of DTPA aerosol transfer in untreated patients with chronic lymphocytic leukemia (CLL) and in patients with a variety of hematologic malignancies that had all been treated with alkylating agents. Two findings emerged: In the untreated CLL patients, the permeability of the upper and middle lung regions was reduced. This may be due to diffuse infiltration by the CLL; and Treatment with cytotoxic agents increased epithelial permeability in both middle and lower lung regions. Further prospective studies are required to determine the cause of the long T50 values in untreated CLL and to confirm that the DTPA transfer test is a sensitive indicator of the damage which eventually leads to pulmonary fibrosis.

Adult↗
PubMed1986

The influence of topical anaesthetic agent at bronchoalveolar lavage upon cellular yield and identification and upon macrophage function.

The influence of cocaine and lignocaine as local anaesthetic agent upon the results obtained at bronchoalveolar lavage was investigated. No differences were found. A functional activity of macrophages was assessed when the cells were stored in lavage fluid. A time-dependent decrease occurred which was related to lack of nutrients rather than the anaesthetic concentration.

Bronchi↗
PubMed1986

Functional images of lung 99Tcm-DTPA aerosol transfer in smokers and nonsmokers.

The large amount of information from dynamic 99Tcm-DTPA lung can be simplified and rendered easily interpretable by the use of functional images. Eight such images have been devised: a maximum count image, a minimum count image, a time of maximum count image, a time of minimum count image, percentage maximum change image, a T50 image, a standard error image and a correlation coefficient image. These images enable the distribution of aerosol after inhalation, the reliability of the calculated T50 value and movement artefacts to be easily identified. They also allow rapid assessment of the distribution of T50 values in the lungs which may be particularly useful in segmental lung disease.

Adult↗