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Biomedical subjects

J A Roberts

Publications and source records attributed to J A Roberts.

At least 19 recordsLinked to original sources
PubMed1992

Interleukin 4 is localized to and released by human mast cells.

Recent attention has focused on the T helper type 2 (Th2) lymphocyte as a source of interleukin 4 (IL-4) in allergic disease. However, Th2 cells themselves require a pulse of IL-4 to initiate this synthesis. Here we provide immunohistochemical evidence of IL-4 localization to human mast cells of the skin and respiratory tract, and demonstrate that immunoglobulin E-dependent stimulation of purified human lung mast cells leads to the rapid release of IL-4 into the extracellular environment. We propose that mast cell activation in an allergic response provides a rapid and local pulse of IL-4 into the local environment essential for the triggering of T lymphocytes into sustained IL-4 production and to initiate inflammatory cell accumulation and activation.

Culture Techniques↗
PubMed1992

The Bevan factor.

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Health Services Accessibility↗
PubMed1992

Is xamoterol safe in chronic airflow obstruction?

We have demonstrated in a group of 10 patients with CAO that treatment with xamoterol (200 mg b.i.d. for 7 days) did not alter lung function or respiratory symptoms. These results suggest that xamoterol can be used to treat mild heart failure in patients with CAO.

Adrenergic beta-Agonists↗
PubMed1992

Autokabalesis: a study of intentional vertical deceleration injuries.

Suicidal jumping from a height appears to be a seasonal problem in Glasgow. A series of 58 individuals were studied, giving a total of 60 jumping incidents. Of these, 21 were killed outright, and of 31 reaching hospital a further 11 subsequently died. Many were young, single, unemployed, adult males, the majority of whom had a known psychiatric diagnosis. Jump heights ranged from 1 to 27 floors and jumps from more than 6 floors were almost always fatal. Below this height mortality was related to the attitude of fall. Overall, 50 per cent mortality occurred at the 3rd floor. A wide range of multiple injuries were sustained and the Injury Severity Score was used to grade these for quantitative comparison. This was found to be highly discriminating between survival and non-survival.

Adolescent↗
PubMed1992

Progesterone receptors in bilateral ovarian ependymoma presenting in pregnancy.

We present a case of a 25-year-old patient at term pregnancy who presented with a bilateral ovarian neoplasm that was histologically and immunohistochemically indistinguishable from ependymoma of the central nervous system. Progesterone receptors were detected in primary and recurrent neoplasms by immunohistochemistry. This is the first case of this rare neoplasm to present during pregnancy as well as with bilateral ovarian involvement. Together with a previously reported case of recurrent ovarian ependymoma with estrogen and progesterone receptors, this case suggests that hormonal responsiveness of this rare neoplasm may be pathogenically significant.

Adult↗
PubMed1992

Continuous infusion of low-dose 5-fluorouracil and radiation therapy for poor-prognosis squamous cell carcinoma of the uterine cervix.

Ten patients with squamous cell carcinoma of the cervix metastatic to periaortic lymph nodes were treated with external-beam radiation therapy and synchronous infusion of intravenous 5-fluorouracil (5-FU) chemotherapy at doses of 350 mg/m2/day. The overall response rate was 90% with four complete responses (CR) and five partial responses (PR). The median duration of response was 11.8 months for CRs and 3.6 months for PRs. Toxicity was tolerable, with gastrointestinal symptoms and myelosuppression being noted most frequently. No patient experienced life-threatening toxicity. Median survival was 7.6 months, with only one patient being alive and free of disease at 2 years. In this pilot study we were unable to demonstrate a beneficial effect of continuous infusion of low doses of 5-FU chemotherapy concurrent with radiation therapy when compared to conventional radiotherapy in patients with advanced squamous cell carcinoma of the cervix.

Carcinoma, Squamous Cell↗
PubMed1992

Preventive treatment against toxocarosis in bovine calves.

Treatment of bovine calves 10-16 days old with an anthelmintic which is effective against immature Toxocara vitulorum killed the parasites, there was no new infection and recontamination of the environment was precluded. When the management of the program was delegated to the livestock officers, approximately 3% of calves scheduled for treatment developed patent infections. The prevalences of toxocarosis on the different farms were correlated with annual rainfall, probably because the longer dry periods associated with lower rainfall killed infective eggs in the environment. The treatment schedules prevailing before the study commenced were ineffective. The prevalence of toxocarosis in the bovine calves on farms in the area with an annual rainfall of about 1000 mm was lower than that in buffalo calves studied previously in the same area.

Animals↗
PubMed1992

Magnetic resonance imaging during intracavitary gynecologic brachytherapy.

The cases of three patients, two with Stage III-B and one with Stage II-B carcinoma of the cervix, are cited to illustrate specific advantages of magnetic resonance (MR) imaging over computed tomography (CT) during intracavitary gynecologic brachytherapy. CT and MR were performed during the first of two intracavitary implants. To obtain artifact-free images with the intracavitary implant in place, a CT- and MR-compatible Fletcher system applicator was used. Although CT failed to differentiate the cervical tumor clearly from surrounding tissues, the area of pathology could be identified on MR by comparing the T1-weighted (T1W) and T2-weighted (T2W) images. Cervical tumors typically exhibit low-signal intensity on T1W and high-signal intensity on T2W scans, whereas paracervical soft tissues demonstrate high intensity on both T1W and T2W images. This contrast permits the size, location, and paracervical involvement of the tumor to be defined by MR. Multiplanar MR images obtained during the patients' intracavitary brachytherapy help demonstrate the actual anatomic relationship between the tumor and the applicator. Isodose distributions displayed on these images show that, in two cases, the tumor margin extended beyond the prescribed isodose line. Thus, MR may prove to be a clinically useful reference during intracavitary brachytherapy for ascertaining radiation dose to actual tumor volume.

Brachytherapy↗
PubMed1992

Vesicoureteral reflux and pyelonephritis in the monkey: a review.

P-fimbriated Escherichia coli, which cause nonobstructive pyelonephritis, adhere to a specific urothelial glycolipid receptor. In either the presence or absence of reflux (in the area of turbulent urine flow) these bacteria ascend the ureter and cause a decrease in ureteral motility. Endotoxin causes peristalsis to cease, leading to ureteral dilatation and change in papillary shape, thus allowing intrarenal reflux and adherence of the bacteria to renal tubules. Bacterial infection of a refluxing ureter may cause reflux to persist. Once the bacteria reach the kidney rapid effects occur at the cellular level with activation of complement followed by granulocytic aggregation and capillary obstruction, causing renal ischemia and damage during reperfusion. In addition, during phagocytosis the respiratory burst occurs, releasing toxic oxygen molecules, which leads to renal tubular death, invasion of the interstitium, microabscess and renal scar formation, that is chronic pyelonephritis, which equates with reflux nephropathy.

Animals↗
PubMed1992

The site of disruption of the bronchial epithelium in asthmatic and non-asthmatic subjects.

BACKGROUND: Attention has recently been focused on the basal cells of the tracheobronchial epithelium as the mechanism of anchorage of the tall columnar cells, which themselves do not appear to form hemidesmosomes with the basement membrane of the epithelium. Residual basal cells have been described as remaining attached to the basement membrane after epithelial denudation. This led this group to formulate the hypothesis that there may be a potential plane of cleavage between the basal cells and the overlying columnar cell layer within the bronchial epithelium, which becomes disrupted in asthma. METHODS: Bronchoalveolar lavage samples were obtained during bronchoscopy from eight patients with atopic asthma and four normal controls. Ultrathin sections of lavage cell pellets were examined by electron microscopy and the number of columnar and basal cells found in each epithelial cell cluster was counted. Cytocentrifuge preparations of the lavage samples from the same subjects were also examined for free epithelial cells and epithelial cell clusters. RESULTS: Electron microscopic examination of the cell pellets showed that basal cells were present in very small numbers in the epithelial clusters in all subjects (mean 0.03 (SE 0.02)/cluster) and the ratio of columnar cells to basal cells was far greater than was encountered in the intact bronchial epithelium (167 nu 4). The cytocentrifuge preparations showed an increased number of epithelial cell clusters and epithelial cells in the asthmatic patients. Although these clusters were similar in size in the two groups of subjects (6.3 nu 5.1 cells/cluster) the ratio of free epithelial cells to cells within the cluster was higher in the non-asthmatic subjects. CONCLUSIONS: It is proposed that shedding of epithelial cells occurs along a suprabasal plane and that there is a potential plane of cleavage between the suprabasal and the basal cell layers, which might be more vulnerable to the various insults.

Adult↗
PubMed1991

Consistent chromosome abnormalities in squamous cell carcinoma of the vulva.

Six squamous cell carcinomas of the vulva (SCV) were karyotyped in short-term culture and in early passages as established cell lines. Each tumor was cytogenetically distinct, contained multiple chromosome rearrangements, and was karyotypically stable in culture. Heterogeneity within individual tumors was manifested by the presence of more than one clonal population, but the clones within each tumor were closely related to one another. Seven consistent chromosome abnormalities found in five of the six tumors were: losses of 3p14-cen, 8pter-p11, 22q13.1-q13.2, and the short arm of the inactive X; chromosome gains involving 3q25-qter and 11q21; and rearrangement breakpoints at 5cen-q12. Ten additional chromosome changes were observed in four of the six SCVs, and together, 22 changes occurred in at least three of the tumors. Two specific losses, 10q23-q25 and 18q22-q23, were present in all four tumors that exhibited biologically aggressive behavior in vivo, but these losses were not found in the tumors of the two long-term survivors. These findings indicate that: 1) SCVs are genetically complex, but homogeneous; 2) loss of 18q22-q23 and loss of 10q23-q25 may be associated with a poor prognosis; and 3) development and progression of SCV appear to result from cumulative effects of altered gene dosage at multiple, consistent loci.

Adult↗
PubMed1991

Evaluating results of clinical trials in treatment of complicated urinary tract infection.

Clinical trials of new drugs should produce results that are not due to chance, inherent differences in groups, or handling of the groups by the investigator. These sources of error may be prevented by having groups of a size that provides sufficient statistical power and thus rules out sample variation. Differences in groups can be prevented by randomization, and double blinding the subjects prevents investigator bias.

Clinical Trials as Topic↗
PubMed1991

The effects of early removal of indwelling urinary catheter after radical hysterectomy.

Radical hysterectomy has long been a primary mode of therapy for selected gynecologic malignancies. The lower urinary tract is an area associated with complications following this procedure. Lack of satisfactory reflex micturition and urinary retention, diminished bladder sensation, infection, and fistula formation are common adverse sequelae. Prolonged indwelling catheterization is a cornerstone of postoperative management after radical hysterectomy. An alternative regimen consisting of early postoperative catheter removal, with a strict voiding schedule, and intermittent self-catheterization (ISC) for postvoid residuals (PVR) was prospectively investigated. Intermittent self-catheterization was initiated only if the PVR 12 hr after catheter removal was greater than 75 ml. Twenty-six patients who underwent radical hysterectomy were studied. Catheters were removed between the fifth and ninth postoperative day. Eighteen patients (69%) had PVRs less than 75 ml at 12 hr and were successfully managed with a strict voiding schedule only. Eight patients (31%) had 12-hr PVRs greater than 75 ml and were managed with a strict voiding schedule and ISC until the PVR was less than 75 ml for two consecutive voids. These patients were evaluated with fluorourodynamics and none had an abnormal study. Compared to 25 historical control patients, study group median indwelling catheter duration was less (6.0 days compared to 30.0 days) with no increase in postoperative complications. On the basis of these data, early removal of indwelling urinary catheters after radical hysterectomy appears to be an acceptable alternative to long-term catheterization.

Catheters, Indwelling↗