Search PubMed⌕ Search

Biomedical subjects

R C Brown

Publications and source records attributed to R C Brown.

At least 181 records · Page 10Linked to original sources
PubMed1984

Catheter-induced cystitis: evaluation by cystosonography.

The bladders of 23 patients with indwelling catheters were examined by ultrasound and cystoscopy. Twelve of the 23 showed changes consistent with bullous cystitis, a catheter-induced reaction of the bladder mucosa that may simulate a bladder tumor on intravenous urography and sonography. The changes seen included a thickened mucosa that was smooth in the early stages, becoming redundant and polypoid in later stages. The mucosa was usually hypoechoic and the lesions were localized on the posterior wall or were diffuse and more severe, depending on the length of catheterization. It is concluded that the sonographic findings in the appropriate clinical setting are suggestive of this entity. Although cystoscopy is not often indicated, cystoscopic findings are diagnostic and biopsy is, therefore, unnecessary.

Aged↗
PubMed1984

Urinary bladder tumors studied by cystosonography. Part I: Detection.

Findings of excretory urography, the principal screening test for bladder tumors, do not accurately depict these tumors. In an attempt to assess the value of sonography in detecting bladder lesions, we used suprapubic sonography to examine 120 patients who presented with various lower urinary tract symptoms. Commercially available equipment was used. Ultrasound detected 16 of the 17 cases of bladder tumor that were confirmed by cystoscopy. In 14 of these, satisfactory images were obtained. Nontechnical factors that affect detection include size and location of the tumor, bladder distention, obesity of the patient, and the operator's skill. Blood clot, benign prostatic hypertrophy, cystitis, and bladder trabeculae can mimic bladder tumors. Sonography may be helpful as an initial screening test for patients suspected of having bladder tumors; however, further experience is needed before conclusions can be made.

Adult↗
PubMed1984

Urinary bladder tumors studied by cystosonography. Part II: Staging.

Correlation between the sonographic staging and the clinical staging as determined by excretory urography, CT, cystoscopy, bimanual examination under anesthesia, and biopsy was possible in 14 of 17 cases of bladder tumor. Ultrasound failed to stage three cases either because the tumor was not seen by sonography (one case) or because of technically suboptimal images (two cases). The cystoscopically obtained biopsy specimens were adequate to make pathologic staging possible in 12 of 14 cases. There was agreement between the sonographic and clinical staging in all 14 cases and with the pathologic staging in all 12 adequately staged cases. The shortcomings of pathologic staging using the cystoscopic biopsy and the criteria of sonographic staging are discussed. Although sonography was demonstrated to be more accurate than conventional methods, further experience is necessary before conclusions can be drawn.

Humans↗
PubMed1984

Chemotactic factor generation by asbestos. Fibre type differences and the effects of leaching.

The generation of chemotactic factors in normal human serum by treatment with chrysotile and crocidolite asbestos was investigated using the Boyden chamber method. Both types of asbestos produced chemotactic activity but not to the same extent. The two fibre types also produced different levels of complement activation as measured by C3 conversion using two dimensional immunoelectrophoresis. While there was a simple correlation between fibre concentration and C3 conversion the production of chemotactic activity declined at high doses of chrysotile. Phosphate buffer treatment reduced the differences between fibre types. The possible role of these phenomena in asbestos-associated disease is discussed.

Asbestos↗
PubMed1984

Anemia as a sign of abdominal pregnancy.

Advanced abdominal pregnancy is an ominous occurrence. The diagnosis is usually made when the physician considers this possibility as the answer to a puzzling obstetric problem. Marked, unexplained anemia, associated with unusual second- and third-trimester signs and symptoms, should warn the physician of the possibility of a near-term abdominal pregnancy.

Adult↗
PubMed1983

The influence of asbestos dust on the oncogenic transformation of C3H10T 1/2 cells.

The cell transforming ability of asbestos dust was investigated using C3H10T 1/2 murine fibroblasts. In a series of experiments both crocidolite and amosite caused no increase in the number of transformed foci over that seen in cultures from untreated cells. The dusts, were, however, capable of augmenting the oncogenic effect of benzo[a]pyrene (BP). This putative synergistic effect was evident when fibres and chemicals were added to cultures as simple mixtures and when BP was adsorbed to the surface of the fibres.

Animals↗
PubMed1983

In vitro genotoxic activities of fibrous erionite.

A high incidence of mesothelioma has been reported from some villages in Cappadocia, Turkey. This type of cancer is usually associated with the inhalation of asbestos, but on the basis of the most prevalent fibre in the dust from these villages, the Turkish outbreak has been attributed to the inhalation of zeolite fibres. A counter hypothesis, based on the detection of very small quantities of chrysotile and tremolite in strata samples and human lung tissue, postulates a significant role of these minerals as one of several factors contributing to pleural disease. A respirable fraction of erionite, (from Oregon, USA, but with similar characteristics to the fibres found in Turkey), has some in vitro genotoxic properties associated with many conventional carcinogens. In this study these fibres caused an increase in morphological transformation and unscheduled DNA repair synthesis (UDS) in C3H10T1/2 cells and UDS in the human lung cell line--A549. It is therefore suggested that exposure to fibrous erionite alone may be sufficient to cause the high incidence of pleural tumours observed in Turkey.

Aluminum Silicates↗
PubMed1983

Intramucosal carcinoma of the gastric antrum complicating Menetrier's disease.

A 48-year-old man presented with haematemesis and was found to have Menetrier's disease. Three and a half years later early gastric cancer was detected at routine follow-up endoscopy. This is the first report of the development of early gastric cancer during follow-up in a case of Menetrier's disease. It is probable that patients with Menetrier's disease are at increased risk of gastric cancer, and should have regular endoscopic follow-up with gastric biopsy.

Gastric Mucosa↗
PubMed1983

Incomplete suppression of parathyroid hormone activity in sarcoidosis presenting with hypercalcaemia.

An adult patient presenting in summertime with sarcoidosis and demonstrating raised levels of serum calcium and 1,25-dihydroxycholecalciferol was observed to have a serum immuno-reactive parathyroid hormone concentration in the mid-normal range. Renal function was normal. Corticosteroid administration quickly depressed serum calcium and 1,25-dihydroxycholecalciferol into the normal range; serum parathyroid hormone also fell to low levels. It was concluded that corticosteroid suppression, when incorporating measurements of serum calcium and 1,25-dihydroxycholecalciferol concentrations, can distinguish between sarcoidosis-related hypercalcaemia and primary hyperparathyroidism. The significance of the changes in parathyroid hormone concentration is obscure.

Adult↗
PubMed1983

Somatomedins in adolescence: a cross-sectional study of the effect of puberty on plasma insulin-like growth factor I and II levels.

To explore the effect of puberty on the somatomedins (SMs), a group of insulin-like peptides which mediate the action of GH on skeletal tissue, we measured SM-C/insulin-like growth factor-I (SM-C/IGF-I) and IGF-II by specific RIAs in 110 adolescents between the ages of 10 and 18 yr. All subjects were in good health and between the 5th and 95th percentiles for height. In both females and males, SM-C/IGF-I levels rose during puberty to a peak approximately 3-fold higher than the average adult level. The rise in SM-C/IGF-I levels corresponded better with the Tanner stage of the adolescents than with their chronological age. IGF-II levels did not rise during puberty and were slightly below adult levels. The dramatic rise in SM-C/IGF-I levels during puberty suggests a role for this SM peptide in the adolescent growth spurt. Furthermore, these data indicate that proper interpretation of SM-C/IGF-I levels during adolescence must include a knowledge of the patient's pubertal development.

Adolescent↗
PubMed1983

Asbestos affects the in vitro uptake and detoxification of aromatic compounds.

A number of mineral dusts were tested for their ability to catalyze the transformation of benzo(a)pyrene from the microcrystalline state into lipid solution. The findings of Lakowicz and his co-workers, that fibrous dusts were more active than nonfibrous dusts, were confirmed. Macromolecular binding metabolites of BaP were formed in A549 cells to a similar extent whether the BaP was added in solution or adsorbed to fibers; however, the level of water-soluble metabolites was lower in cultures treated with adsorbed hydrocarbon. It was found that asbestos can also inhibit the accumulation of 1-naphthyl glucuronide in cultures treated with 1-naphthol. The significance of this in asbestos pathogenesis is briefly discussed.

Animals↗
PubMed1983

Study of the cell-transforming ability of amosite and crocidolite asbestos and the ability to induce changes in the metabolism and macromolecular binding of benzo(a)pyrene in C3H10T1/2 cells.

The cell transforming ability of asbestos dusts was investigated using C3H10T1/2 murine fibroblasts. In a series of experiments, crocidolite and amosite caused no increase in the number of transformed colonies over that seen in cultures from untreated cells. The dusts were, however, capable of augmenting the oncogenic effect of benzo(a)pyrene. This synergistic effect was evident when fibers and chemicals were added to cultures as simple mixtures and when benzo(a)pyrene was adsorbed to the surface of fibers. Asbestos dust did not, however, appear to exert its oncogenic enhancing effect by modifying the metabolism of benzo(a)pyrene in C3H10T1/2 cells.

Animals↗
PubMed1983

Angiotensin converting enzyme in the serum of rats with experimental silicosis.

The development of silicosis in rats given an intratracheal dose of silica was followed both by normal histological procedures and by measuring the level of angiotensin converting enzyme in the serum. The histological changes demonstrated a variable response due to the uneven deposition of material given by the intratracheal route. While the enzyme activity in the serum increased in the treated group it was not well correlated with the histological changes.

Animals↗
PubMed1983

Vitamin D3 metabolites in hypercalcaemic adults after kidney transplantation.

Vitamin D3 metabolites and iPTH were measured in 26 patients at various times after renal transplantation. Hypercalcaemia (serum Ca greater than 2.62 mmol/L, 14 patients) was associated with hyperparathyroidism (p less than 0.02) and raised 1,25(OH)2D3 (p less than 0.05) but raised 1,25(OH)2D3 was also found in most patients in the normocalcaemic group. Lower 25(OH)D3 concentrations were found in the group with normal 1,25(OH)2D3 compared to the group with elevated 1,25(OH)2D3 (p less than 0.05). Low values of 24,25(OH)2D3 were found in both the normocalcaemic and hypercalcaemic patients (p less than 0.002). Impaired creatinine clearance (less than or equal to 55 ml/min, mean: 38 ml/min) was not associated with reduced 1,25(OH)2D3. No difference in D3 metabolites was found between hypophosphataemic and normophosphataemic patients.

Adult↗
PubMed1982

Biological effects of tremolite.

Tremolite is an amphibole which has been implicated in a variety of disease patterns in different parts of the world. It occurs in a number of phases, which are chemically identical but have specific physical characteristics. In an attempt to clarify the epidemiological findings, tremolite fibres of 3 specific forms--A, B and C--were characterized and studied for biological activity by: (i) in vivo intrapleural injection of rats (2 separate experiments--1 with poor survival). (ii) in vitro enzyme release from mouse peritoneal macrophages (iii) in vitro giant-cell formation in A549 cultures (iv) in vitro cytotoxicity for V79-4 cells. Sample C, which contained more long thin fibres than A and B, was alone in producing mesotheliomas. C, but not A or B, induced LDH and B-glucuronidase enzyme release, and induced giant cells. A was not cytotoxic, B moderately cytotoxic and C as highly cytotoxic as UICC crocidolite. The in vivo studies were marred by being split between 2 experiments, of which the second had poor survival. We are aware of the weakness of our in vivo data, but as Tremolite C was being considered for commercial use on the European market we felt it timely to submit our findings for publication.

Animals↗