Search PubMed⌕ Search

Biomedical subjects

J Matthews

Publications and source records attributed to J Matthews.

At least 145 records · Page 8Linked to original sources
PubMed1988

Proliferation patterns and aneuploidy in adenomatous polyps of the colon.

The frequency of aneuploidy and the proliferative activity of 57 colorectal adenomatous polyps was investigated by static cytophotometry and compared with 43 adenocarcinomas and 60 samples of normal mucosa. Twenty per cent of the adenomas contained aneuploid cells compared with 63 per cent of the adenocarcinomas. Except in the case of villous adenomas, there was a general increase in the proliferative activity of the diploid adenomas with increasing degrees of dysplasia. All of the adenomas showed an increase in proliferation compared with normal mucosa. There was a positive correlation between the size of the diploid adenomas and proliferative activity (P less than 0.001).

Adenocarcinoma↗
PubMed1988

Comparison of absorbable materials for surgical haemostasis.

The haemostatic effect of two new materials has been compared with surgical gauze and oxidized cellulose using a standardized liver laceration in New Zealand White rabbits. Following excision of a 3 cm2 disc of tissue from the liver, 42 rabbits were randomized to the use of gauze swabs (n = 6), oxidized cellulose (Surgicel) (n = 12), porcine collagen (Medistat) (n = 12) or calcium alginate (Kaltostat) (n = 12) to control the resulting haemorrhage. Blood loss and time to haemostasis were accurately recorded. The absorbable materials were left in situ and animals killed between 2 weeks and 6 months later to examine speed of absorption and resulting adhesions. Calcium alginate stopped bleeding in less than 3 min in all animals compared with a mean (+/- s.e.m.) of 5.7 +/- 0.75 min for porcine collagen, 12.5 +/- 0.9 min for oxidized cellulose and greater than 15 min with gauze (P less than 0.001). Oxidized cellulose and calcium alginate reabsorbed within 3 months leaving a fibrous scar, but a vigorous foreign body reaction was seen with porcine collagen which caused intestinal obstruction in 5 out of 12 animals within 3 months.

Absorption↗
PubMed1987

Importance of cellular DNA content in pre-malignant breast disease and pre-invasive carcinoma of the female breast.

The risk of malignant change in pre-invasive breast disease such as proliferative atypia (PA) or the risk of invasive carcinoma arising from ductal carcinoma in situ (DCIS) remains uncertain in individual women because of the absence of any prognostic criteria. In order to clarify this, the cellular DNA content (ploidy) of 51 screen-detected lesions has been investigated. Cellular DNA measurements were made by static cytometry following Feulgen staining of disaggregated tissue sections and the resulting histograms classified as either diploid or aneuploid. Thirteen cases of PA and twelve of DCIS were compared with twenty-six biopsies showing DCIS with adjacent invasive carcinoma (DCIS + Ca). In the latter group, ploidy of the invasive carcinoma was compared with the associated DCIS in 16 cases. Aneuploid cells were found in approximately 30 per cent of PA and DCIS lesions but in 23 of 26 cases of DCIS + Ca. Of 16 assessable cases of co-existing DCIS and micro-invasive carcinoma both were aneuploid in 11, both diploid in 1, and in 4 cases the DCIS was aneuploid whereas the invasive carcinoma was diploid. These results suggest that aneuploidy may be of value in predicting the most biologically aggressive of these pre-invasive lesions.

Aged↗
PubMed1987

Kinetic changes in experimental colonic urinary diversion.

An experimental model of colonic urinary diversion was performed on male Wistar rats to see if faeces, urine or a faeces and urine mixture produces tumours. Cell kinetic techniques, including the crypt cell production rate, and cellular DNA measurement were used to examine the effect of urine and of faeces on the colonic mucosa. Urinary diversion into the colon significantly increased colonic crypt activity. Tumours were found at the anastomosis when urine and faeces were mixed at 4 months, and at 6 months with urine alone.

Animals↗
PubMed1987

Transformation frequency increases with increase in agitation rate of chemostat-cultivated Escherichia coli K12, strain C-600.

The transformation frequency of Escherichia coli C-600, continuously cultivated in a chemostat operated at constant dilution rate, increased with increase in agitation rate (impeller speed). Cell counts at each impeller speed remained approximately constant. The phenomenon correlated with changes in mean cell volume associated with the changes in agitation rate.

Bacteriological Techniques↗
PubMed1987

The effect of acid perfusion on mucosal blood flow and intramural pH of rabbit duodenum.

To evaluate the role of blood flow for acid tolerance of the duodenal mucosa, we perfused the duodenums of anesthetized rabbits with different concentrations of hydrochloric acid (HCl). Acid perfusion stimulated blood flow to the duodenal wall in a concentration-dependent fashion up to 80 mmol/L HCl (0 mmol/L; 0.44 +/- 0.05, 10 mmol/L; 0.84 +/- 0.14, 50 mmol/L; 1.44 +/- 0.11, 80 mmol/L; 2.03 +/- 0.12, 100 mmol/L; 1.82 +/- 0.07 ml/gm/min X +/- SEM). The pH in the lamina propria of the mucosa, which was measured with antimony microelectrodes was not changed in experiments during perfusion with 50 and with 80 mmol/L HCl in normotension. Acidosis in the lamina propria could be demonstrated only when the duodenum was perfused with 100 and with 80 mmol/L HCl combined with hemorrhagic hypotension. Damage to the mucosa, which developed after 30 and 60 minutes of acid perfusion, also showed a H+-dependent pattern. Reduction of blood flow by hemorrhagic hypotension aggravated the morphologic damage. We conclude that luminal acid stimulates blood flow in the duodenum. The decrease in blood flow induced by hypotension results in a greater susceptibility to mucosal damage.

Animals↗
PubMed1986

beta-Endorphin/beta-lipotropin immunoreactivity in endogenous depression. Effect of dexamethasone.

This study addresses the question of whether pituitary peptides (ie, beta-endorphin) show regulatory disruption in endogenous depression and, if so, does it co-occur in the same subjects who show cortisol dysregulation. Endogenously depressed patients and psychiatric controls from three centers were evaluated, when not taking medications, and studied for plasma cortisol and beta-endorphin levels. Plasma samples were taken at four time points over one hour, on the basal day, and 16 hours after 1 mg of dexamethasone. From 33% to 69% of the endogenous patients were abnormal in their postdexamethasone cortisol levels, and from 50% to 69% were abnormal on postdexamethasone beta-endorphin values (vs 0% and 8%, respectively, for controls). When endogenous subjects were evaluated for abnormality on both cortisol and beta-endorphin, after dexamethasone, it was found that the two measures of hypothalamic-pituitary-adrenal dysfunction did not necessarily co-vary. In fact when having either abnormal beta-endorphin or cortisol levels (or both) was used as a biological marker a larger number of the endogenous patients were detected than with either measure alone. Our conclusions are as follows: Plasma beta-endorphin shows a circadian rhythm similar to that seen with corticotropin (ACTH) and is suppressable by dexamethasone. In many endogenous patients plasma beta-endorphin levels escape from dexamethasone suppression. Many of these subjects are not cortisol escapers. When abnormality of either the beta-endorphin or cortisol is considered it is clear that both levels of the hypothalamic-pituitary-adrenal axis can be dysregulated in endogenous depression.

Adolescent↗
PubMed1986

Prostatic carcinoma cell DNA content measured by flow cytometry and its relation to clinical outcome.

DNA content of prostate tumour cells has been measured by flow cytometry of cell suspensions prepared from fixed tissue by an enzyme disaggregation technique. Two classes of tumours have been identified: diploid tumours, with a DNA content similar to benign cells and aneuploid tumours with grossly abnormal DNA values. The prognosis for the aneuploid tumours was significantly worse than diploid tumours (P less than 0.001). When ploidy is combined with histological grading, here using the Gleason numerical system, it is possible to predict which patients, whatever their age at diagnosis, will die from their tumour and which patients will probably die before their tumour kills them. With these facts it is possible to select patients for active or expectant treatment.

Aged↗
PubMed1986

Possible hazards from irradiation with the carbon dioxide laser.

Previous investigators, using relatively high irradiance levels, have been unable to demonstrate viable tissue in the plume during carbon dioxide laser vaporization. Our study was undertaken to reinvestigate this possibility, particularly at the lower irradiance levels that are currently in clinical use. Fresh post-mortem skin was injected with a known quantity of bacterial spores and vaporized at different levels of irradiance and energy fluence. The plume and splatter were collected and cultured. Spores were found following the vaporization of five of 13 specimens treated at an irradiance of less than 500 W/cm2, while there were none in the 20 specimens treated at an irradiance of greater than 997 W/cm2. These results show that the widely accepted assumption that the carbon dioxide laser produces a sterile field may be false and that viable particles may be disseminated during vaporization at low irradiance. This may be important when considering the treatment of potentially infectious lesions.

Air Microbiology↗
PubMed1986

Human chorionic gonadotrophin expression in colorectal adenocarcinoma.

The presence of human chorionic gonadotrophin (HCG) in colorectal adenocarcinoma was studied histologically in 45 tumors using immunoperoxidase technique. Ten neoplasms (22.2 percent) contained HCG-positive tumor cells. These cells were present mostly at the periphery of the tumors. Many formed parts of glands, while some were arranged in syncytial clumps or columns, or singularly. Thus, these tumor cells resembled trophoblastic tissue not only in being HCG-positive but also in their peripheral distribution and occasionally in morphologic appearance. HCG-positive tumors were seen more commonly in the rectosigmoid region (90 percent) and were more aggressive than HCG-negative tumors. In this study, lymph node or liver metastases were present in 70 percent of HCG-positive tumors compared with 29 percent of negative tumors--a difference which is statistically significant.

Adenocarcinoma↗
PubMed1986

Changes in crypt cell DNA content during experimental colonic carcinogenesis.

Changes in colonic crypt cell DNA content have been monitored during experimental carcinogenesis. Colonic tumours were induced in Wistar rats using 12 consecutive subcutaneous injections of azoxymethane at a dose of 10 mg kg-1. Ten rats were killed at each of 10, 15, 20 and 25 weeks after the initial injection. On sacrifice the descending colon, plus any polyps or tumours with their adjacent mucosa, was removed, fixed and processed to paraffin wax. Sections were stained for DNA by the Feulgen reaction. Using an integrating microdensitometer the DNA content of the proliferative and functional cells was measured and expressed as a percentage of the stem cell DNA content. As carcinogenesis progressed there was an increase in the mean amount of DNA in the proliferative and functional cells in the distal colon although the tissue was histologically normal. The transitional mucosa adjacent to tumours showed the same increases as the 25 week distal colon. In the adenomas, there was a further increase in the DNA content of the functional cells. These results are probably a reflection of the increase in the number of dividing cells in the higher positions of the colonic crypts during carcinogenesis.

Animals↗
PubMed1986

A comparative study of ciprofloxacin and trimethoprim in the treatment of urinary tract infections in geriatric patients.

A prospective, comparative clinical trial of ciprofloxacin (100 mg bd) versus trimethoprim (200 mg bd), both for five days, was carried out in 40 geriatric patients with urinary tract infection. Thirty-two could be assessed for drug efficacy, and all forty for toxicity studies. Both drugs were equally safe, and ciprofloxacin was at least as effective as trimethoprim as far as clinical response was concerned. Ciprofloxacin appeared more effective in eradication of bacteria. Antibacterial activity was found in urine and faeces up to five days after stopping ciprofloxacin therapy.

Aged↗