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Biomedical subjects

C Ward

Publications and source records attributed to C Ward.

At least 163 records · Page 9Linked to original sources
PubMed1990

Effect of donor age on the growth in vitro of cells obtained from human trabecular bone.

The proliferation of human bone-derived cells (BDCs) was assessed in vitro, using [3H]thymidine incorporation and cell counting in a haemacytometer. The cells were cultured from human trabecular bone from 87 patients aged 2-88 years. The in vitro growth of these cells was unaffected by the chronological age of the donor. However, the cell number at confluence was shown to decrease with increasing donor age, this trend being most marked after 60 years of age. Other assays of the metabolic efficiency of the BDCs, namely, total protein, osteocalcin, and alkaline phosphatase synthesis, did not show any change with increasing donor age. These results suggest that while the ability of individual cells to divide and to perform specific synthetic activities is unimpaired with increasing age, other subtler changes may occur, leading to a decrease in the bone's osteogenic capacity.

Adolescent↗
PubMed1990

Immunoscintigraphy of colorectal cancer with an antibody to epithelial membrane antigen (EMA).

Immunoperoxidase staining of LICR-LON M8, a mouse monoclonal antibody reactive with epithelial membrane antigen, showed a strong reaction with colorectal cancer. This finding prompted an immunoscintigraphic study of colorectal cancer patients using this antibody. Sixteen patients had external gamma scintigraphy after intravenous injection of indium 111-labeled M8. Positive scans were obtained in 11 of the 13 patients with primary colorectal cancers, and 2 of the 3 patients with recurrent tumors. The high indium 111 background in the liver prevented the detection of hepatic metastases in 5 patients. Twelve patients had samples taken of tumor, normal colon, and venous blood at the time of surgery. The ratio of labeled antibody uptake in tumor to that of blood was 5.1 (+/- 3.6 S.D.), which was significantly different (P = 0.001) to that of the similar ratio for normal colon (2.0 +/- 1.6 S.D.). The tumor to normal colon uptake ratio was 2.6 (+/- 1.3 S.D.). These results suggest a specific uptake of indium 111-labeled M8 by colorectal cancer.

Aged↗
PubMed1990

Genotoxicity and cell cycle effects of platinum-based imaging agents in cisplatin-resistant human tumour cells.

A series of cis-dichloroplatinum(II) 2,3-diaminopropionamide complexes synthesised as potential imaging agents was tested for activity against a human ovarian tumour cell line (CI-80-13S) with high natural resistance to cisplatin and carboplatin as compared with other human cells. The most potent compound, the dimethyl ester of dichloro-[4-(methyleneiminodiacetic acid)phenyl (2',3'-diamino-propionamide)]platinum(II) (complex III), exhibited toxicity towards CI-80-13S cells similar to that observed in other cell lines, an effect that was not shown by the ligand alone or by cis-dichloroplatinum(II) 2,3-diaminopropionamide. However, complex III ester reproduced the genotoxic effects of cisplatin as judged by differential inactivation of two strains of adenovirus and by inhibition of cellular DNA and RNA synthesis; no major differences in these properties were observed between CI-80-13S and cisplatin-sensitive cells. Substantial inhibition of DNA and RNA synthesis was found within 2 h of treatment, much earlier than the effect of cisplatin. Complex III ester, which was 30- to 100-fold less potent than cisplatin, inhibited cell cycle progression in a similar way to equitoxic cisplatin, with cells accumulating in G2 at a dose of low toxicity and being arrested in all stages at higher levels. The latter in combination with colcemid caused extensive fragmentation of CI-80-13S cells. These results suggest that the mechanism of toxicity of such complexes involves factors, in addition to DNA damage, which rapidly inhibit nucleic acid synthesis and overcome natural resistance to cisplatin in the CI-80-13S cell line.

Adenoviridae↗
PubMed1990

The actions of GR32191B, a thromboxane receptor antagonist, on the effects of inhaled PAF on human airways.

We investigated acute bronchoconstriction and changes in airway responsiveness to methacholine following the inhalation of platelet activating factor (PAF) in an open study of 12 non-asthmatic subjects. Ventilatory function was monitored using a flow rate at 30% of vital capacity (V30) and airway responsiveness was measured as PD40V30, i.e. the dose of metacholine causing a 40% fall in V30. PAF (3-422 micrograms) resulted in dose-related acute bronchoconstriction in 10 of the 12 subjects. There was no association between the airway responsiveness to PAF and to methacholine. Ten subjects showed some increase in airway responsiveness to methacholine 1 or 3 days following PAF. Overall, these changes were statistically significant (P less than 0.05) but were of small magnitude (geometric mean PD40V30pre-PAF = 457 micrograms; 24 hr after PAF = 259 micrograms; 72 hr after PAF = 258 micrograms) and variable: only seven subjects showing increased airway responsiveness on both day 1 and day 3 after PAF. Six subjects who appeared to show increases in airway responsiveness following PAF were re-studied with the inhaled PAF pre-medicated by either placebo or a specific thromboxane receptor antagonist (GR32191B) in a double-blind fashion. GR32191B did not reduce the acute bronchoconstriction due to PAF. In this part of the study, these six subjects did not show significant increases in airway responsiveness following the placebo pre-medicated PAF challenge and so no effect of the drug on airway responsiveness could be shown.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Inhalation↗
PubMed1990

The pharmacokinetics of the antidepressant tianeptine and its main metabolite in healthy humans--influence of alcohol co-administration.

A balanced 3 way cross-over study involving 12 young healthy volunteers (6 men and 6 women) was used to determine the pharmacokinetic parameters of the antidepressant tianeptine following a single dose administered by oral and intravenous route. The influence of alcohol on the pharmacokinetics of tianeptine when given per os was also investigated. Kinetic parameters of metabolite MC5, the C5 side chain beta-oxidation product of tianeptine, were simultaneously determined. Following intravenous administration total clearance and volume of distribution of tianeptine were 230 +/- 59 ml.min-1 and 0.47 +/- 0.14 l.kg-1 respectively. When given orally, tianeptine was absorbed rapidly (tmax = 0.94 +/- 0.47 h). The mean systemic availability was estimated to be 99 +/- 29%. Tianeptine was eliminated from plasma with a half-life of 2.5 +/- 1.1 h, mainly via extrarenal route since its renal clearance averaged 0.38 +/- 0.47 ml.min-1. Plasma levels of metabolite MC5 were lower than those of the parent drug but decreased with a longer half-life (7.2 +/- 5.7 h). Alcohol co-administration decreased tianeptine absorption rate and lowered tianeptine plasma levels by about 30% but did not affect those of the MC5 metabolite.

Administration, Oral↗
PubMed1990

The reversible effect of lignocaine on the stimulated metabolic activity of bronchoalveolar lavage cells.

Lignocaine concentrations were measured in the aspirate from a low volume (100 ml) bronchoalveolar lavage (BAL) in twenty patients who had received topical 4% lignocaine as required, and compared to those found in the aspirate from a 180 ml BAL in ten patients who had received 1.5% isotonic lignocaine. The median BAL supernatant lignocaine concentration was significantly lower at 0.14 mM (range 0.07-0.44 mM) in the group who received 1.5% lignocaine, compared to 1.08 mM (range 0.03-7.05 mM) in those given 4% lignocaine (p less than 0.01). The effect of increasing concentrations of lignocaine on BAL neutrophil and pulmonary macrophage metabolic activity, as assessed by latex-stimulated luminol- and lucigenin-amplified chemiluminescence (CL), respectively, in mixed BAL cell populations, were measured following preincubation of "washed" harvested BAL cells with 0.4-8.0 mM lignocaine. There was no demonstrable decline in either cell activity with lignocaine concentrations of up to 2 mM, with dose-dependent inhibition of both above this threshold. Cell viability was unaffected. In a further experiment, the inhibition induced by 8 mM lignocaine on both pulmonary macrophage (lucigenin-amplified CL of harvested BAL cells) and isolated peripheral blood neutrophil metabolic activity was completely reversed by a single "wash", following both 30 and 60 min incubations at 4 degrees C, which was equivalent to resuspending harvested BAL cells in fresh medium after separation from BAL supernatant.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

The relative contribution of bronchoalveolar macrophages and neutrophils to lucigenin- and luminol-amplified chemiluminescence.

The relationship between differential cell counts and latex-stimulated luminol and lucigenin-amplified chemiluminescence (CL) was investigated by mixing alveolar macrophages (AM) obtained at bronchoalveolar lavage (BAL) with allogeneic peripheral blood neutrophils (PMN) in varying proportions. In 5 non-asthmatic subjects, the mean luminol-amplified CL increased linearly from 2.1 (0.9 SEM) x 10(5) counts per second (cps) with less than 2% PMN, greater than 96% AM to 47.3 (11.1 SEM) x 10(5) cps with greater than 94% PMN, 0% AM (r = 0.996, p less than 0.001). The regression had a y-intercept indistinguishable from 0 cps, suggesting that luminol-amplified CL exclusively reflected PMN activity. Using the same technique, the mean lucigenin-amplified CL showed a fall from 35 (2.3 SEM) x 10(5) cps with a cell population of greater than 96% AM, less than 2% PMN to 20 (2.3 SEM) x 10(5) cps with 0% AM, greater than 94% PMN. Both PMN and AM appeared to contribute to lucigenin-amplified CL, with AM contributing approximately 1.7 times as much activity per cell as PMN. Lucigenin-amplified CL appeared to be an appropriate technique for measuring AM activity when the proportion of PMN in mixed cell populations was small. A linear relationship was found between percent PMN count and luminol-amplified CL measured in a mixed BAL cell population from asthmatic subjects (p less than 0.01) and non-asthmatic controls (p less than 0.01). The slope of this regression line was significantly greater for subjects with asthma than for control subjects (p less than 0.01), suggesting a uniform increase in PMN activity in cells obtained from asthmatic airways.

Acridines↗
PubMed1990

Platelet-activating factor in bronchoalveolar lavage fluid from asthmatic subjects.

Bronchoalveolar lavage (BAL) was performed on 28 asthma patients, 7 patients with emphysema and 11 control subjects. Total and differential cell counts were performed and cellular metabolic activity was assessed using luminol and lucigenin amplified chemiluminescence. BAL supernatants were assayed for platelet-activating factor (PAF) and lyso-PAF using a sensitive guinea-pig bioassay. Eight of the asthma patients but none of the emphysema patients or control subjects had PAF in their BAL fluid. Lyso-PAF was measurable in BAL fluid in most subjects and no differences were detected between groups. Among the asthma patients, the presence of PAF in BAL supernatant was significantly associated with a combination of low neutrophil and high lymphocyte counts (p less than 0.05) and with macrophage metabolic activity as assessed by lucigenin chemiluminescence (p less than 0.05).

Adolescent↗
PubMed1989

Scopolamine and benzodiazepine models of dementia: cross-reversals by Ro 15-1788 and physostigmine.

The muscarinic antagonist scopolamine and the benzodiazepine lorazepam both produce transient impairments in memory and attention in normal volunteers. These impairments can be reversed by appropriate agents such as the cholinesterase inhibitor physostigmine in the case of scopolamine or the benzodiazepine antagonist Ro 15-1788 in the case of lorazepam. In this paper we investigated the pharmacological specificity of these reversals by examining the interactions of scopolamine and Ro 15-1788 and of lorazepam and physostigmine. There was no evidence that the effects of scopolamine and lorazepam on cognitive function could be attenuated by Ro 15-1788 and physostigmine, respectively. The results are discussed in terms of pharmacological models of Alzheimer's disease.

Acoustic Stimulation↗
PubMed1989

The effect of filtration on absolute and differential cell counts in fluid obtained at bronchoalveolar lavage.

We have studied the effects of filtering mucus from bronchoalveolar lavage (BAL) fluid on its cellular contents. We examined BAL fluid from 18 patients without excessive endobronchial mucus, and from three patients with bronchiectasis. In the non-bronchiectatic subjects there was a fall of 18% in mean absolute cell count from 2.66 +/- SD 1.9 x 10(9) l-1 to 2.18 +/- 1.4 x 10(9) l-1 (P less than 0.05) as a result of filtration. This was due to a selective loss of macrophages and there were no significant changes in the absolute numbers of either lymphocytes or neutrophils. The differential macrophage count fell from a mean of 82 +/- 14% to 76 +/- 16%, while the mean differential lymphocyte count rose from 14 +/- 7% to 19 +/- 9% and the mean differential neutrophil count increased slightly from 4 +/- 4% to 5 +/- 4%. In the three patients with bronchiectasis the absolute cell counts were grossly raised, due almost entirely to an excess of neutrophils. In these patients, filtration reduced the absolute macrophage count by 61% and the absolute neutrophil count by 27%. Overall, change in absolute cell count correlated significantly with mucus volume (r = 0.76, P less than 0.05). Removal of mucus by filtration affects absolute cell count and may have a selective effect on cell numbers. If filtration of BAL fluid is unavoidable, its effect on cell counts should be clearly established if data from different centres are to be meaningfully compared.

Adult↗
PubMed1989

The effect of drugs on the cell cycle of Giardia intestinalis.

Flow cytometric analysis of the binucleated protozoan parasite Giardia intestinalis gave DNA histograms with a broad G1 peak and a definable G2 + M peak with twice the DNA content of G1. Twenty-four hour treatment with metronidazole arrested cell cycle progression of susceptible trophozoites in the G2 + M phase, but had no effect, even at toxic doses, on the DNA histogram of a line selected for resistance to metronidazole. Furazolidone was inhibitory to both stocks, causing an arrest in the S and G2 + M phases. Inhibitors of the mammalian cell cycle were also tested. Hydroxyurea, which blocks mammalian cells in G1/S, and razoxane, which blocks in G2 + M, arrested trophozoites in the G2 + M phase whereas colchicine and gamma-irradiation had little or no effect on the cell cycle of G. intestinalis. These results suggest that the cell cycle of G. intestinalis may be controlled in a different manner from mammalian cells.

Animals↗
PubMed1989

Reflex sympathetic dystrophy (algoneurodystrophy): temperature studies in the upper limb.

The temperature response of the hands to mild cold stress (20 degrees C for one minute) has been measured in 20 normal subjects, 20 patients with reflex sympathetic dystrophy (RSD) and 10 patients with chronic upper limb pain (CULP) of uncertain origin. The results of RSD and CULP groups were significantly (p less than 0.05) different from normal but were indistinguishable. For each patient, 11 variables obtained from the thermal stress test were compared with the normal range. Ten of the RSD group and seven of the CULP group had four or more abnormal variables and were considered to have a thermoregulatory abnormality. The thermal stress test is useful in the objective assessment of RSD. It is non-invasive, patient acceptable and reproducible.

Adult↗
PubMed1989

Lymphocyte subsets in bronchoalveolar lavage fluid obtained from stable asthmatics, and their correlations with bronchial responsiveness.

Bronchial responsiveness to methacholine (PD20 FEV1) was assessed in 22 asthmatic subjects approximately 5 days prior to bronchoalveolar lavage (BAL). A PD20 FEV1 could not be attained in 20 matched controls with normal pulmonary function. BAL was performed in all subjects, 3 x 60 ml aliquots of buffered saline being introduced into a segment of the middle lobe and immediately aspirated into siliconized glassware at 4 degrees C. After filtration, cells were counted, and the cell pellet resuspended in medium 199. Cytospin slides were prepared and a differential cell count performed. Lymphocyte subsets were identified by labelling further cytospin preparations with specific monoclonal antibodies (Leu series) against T3, T4, T8 and B cell markers, followed by a fluorescent antibody marker. The slides were coded, and 100 lymphocytes were then randomly scanned for fluorescence on each cytospin preparation. The median total lymphocyte counts were significantly greater in the asthmatic subjects, but this increase was confined to the T cell subgroups. The mean T4/T8 ratio was similar in asthmatic (1.51) and control (1.45) subjects. Log PD20 FEV1 correlated positively with total lymphocyte counts (r = 0.42, P less than 0.05), and with total T8 counts (r = 0.60, P less than 0.05). Correlations between bronchial responsiveness and T3, T4 and B lymphocyte numbers all failed to reach significance, and there was no correlation with T4/T8 ratios. The increase in BAL lymphocyte counts in asthma appears to be due to an absolute increase in T cell subsets, especially the T8 lymphocyte subgroup, and is most marked in mild asthmatics.

Adolescent↗
PubMed1989

Coarctation of the aorta: MR imaging in late postoperative assessment.

Thirty-six patients were studied with magnetic resonance (MR) imaging 2-29 years after repair of coarctation of the aorta, and the findings were compared with clinical data and results of echocardiography, catheterization, angiography, and surgery. A satisfactory echocardiographic examination of the isthmus was achieved in 28 patients. Comparison with data from gradient measurements at catheterization and Doppler ultrasound shows that the reduction of lumen diameter correlates well with the gradient and that restenosis at the site of the repair can be suspected when the percentage of stenosis at the isthmus is greater than 50%. MR imaging showed a Dacron patch aneurysm in three patients. Cine MR imaging showed systolic signal loss in the ascending aorta that was presumed to be due, among other factors, to turbulent flow generated from a bicuspid valve. Similar signal loss was seen in the descending aorta distal to the site of the coarctation repair, but this was not related to the presence or absence of a gradient. Aortic compliance measured from transverse MR systolic and diastolic images was abnormally low, suggesting it may be a factor causing systolic hypertension after coarctation repair. MR imaging is a reliable and accurate noninvasive method likely to supersede other methods of assessing the aorta and isthmus following coarctation repair.

Adolescent↗
PubMed1989

Does myeloma secrete an osteoblast inhibiting factor?

Unlike most other tumours, myeloma causes bone destruction without an osteoblastic reaction; we tried to assess whether myeloma secretes a humoral factor that inhibits osteoblasts. Human bone-derived cells were either co-cultured with myeloma cells, or cultured in medium conditioned by myeloma cells. Bone-derived cell growth was measured by cell counts and by uptake of tritiated thymidine (3H-Tdr); growth was inhibited when cultured in medium conditioned by myeloma cells and some inhibition was seen when the bone-derived cells were co-cultured with myeloma cells. The inhibiting effect was dose-dependent and also dependent upon the density of the myeloma cells conditioning the medium. The results of our study suggest that myeloma secretes an osteoblast inhibiting factor of less than 50,000 Dalton molecular weight.

Cell Count↗