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Biomedical subjects

A Rhodes

Publications and source records attributed to A Rhodes.

13 recordsLinked to original sources
PubMed1992

Radioimmunoscintigraphy of metastatic breast carcinoma.

Seventeen patients with breast cancer underwent preoperative radioimmunoscintigraphy (RIS). Planar and tomographic imaging techniques (single photon emission computerised tomography--SPECT) were studied using Indium-111-labelled anti-epithelial membrane antigen (EMA) antibodies for tumour localisation. Overall imaging sensitivities were reasonable with correct identification of around 90% of primary lesions and 50% of secondary lesions. Planar imaging was more sensitive than SPECT for identification of superficial lesions such as the primary lesions (88% vs 56%) and axillary metastases (59% vs 53%). SPECT was necessary, however, for detection of deeper lesions such as internal mammary chain metastases and often served as an adjunct rather than an alternative to planar imaging. RIS, therefore, may contribute to more accurate staging of breast cancer, although further technical advances in RIS would enhance this contribution.

Adult↗
PubMed1991

Inhibition of heterologous strains of HIV by antisense RNA.

Antisense RNA can inhibit the expression of messenger RNAs (mRNAs) to which they are complementary by a variety of mechanisms and might provide the basis for antiviral therapies of high selectivity. In a previous study of six retrovirally expressed antisense RNAs targeted to HIV-1IIIB, we found that two significantly reduced HIV-1IIIB replication. Here we test the degree to which this inhibitory effect tolerates the natural variation found in the nucleotide sequence of different strains of HIV-1. We show that the longer of the two inhibitory antisense RNAs (600 bases) inhibits replication of HIV strains RF, MN and SF2 to at least as great an extent as it does the homologous strain. In contrast, the shorter (71 bases) does not inhibit replication of the heterologous strains. An examination of the predicted positions of the mismatches in the duplexes formed between the IIIB antisense RNAs and the mRNAs of heterologous strains suggests that one requirement of an inhibitory antisense RNA is that it can form a perfect duplex with its target mRNA of at least some 51-64 base-pairs. Although the observations presented here are not definitive proof of this, they are reminiscent of the structural requirements deduced for the double-stranded RNA-mediated induction of interferon and the activation of interferon-induced 2', 5'-oligo(A) synthetase and protein kinase. We tested the ability of antisense RNA to inhibit HIV replication in Jurkat, CEM, U937 and HeLa-T4 cells. The level of inhibition of HIV-1IIIB replication varied according to the cell line in which it was expressed, but in all cases was significant.

Animals↗
PubMed1990

Inhibition of human immunodeficiency virus replication in cell culture by endogenously synthesized antisense RNA.

Antisense RNA, which has a sequence complementary to mRNA, may provide the basis for antiviral therapies of high selectivity. We have explored the inhibitory effect of six antisense RNAs upon the replication of human immunodeficiency virus (HIV) in cell culture. We chose regions of the HIV genome to test whether sequences required for splicing or for translation initiation were more susceptible to antisense RNA interference. Our results suggest that inhibitory antisense RNAs contain sequences complementary to the AUG initiation codon of the tat gene and have a comparatively low tendency to form intramolecular base pairs which would interfere with intermolecular duplex formation. Inhibition can be substantial (over 70%) but is transient. Transience does not result from mutation of the input virus. Inhibition was not a consequence of the induction of interferon by antisense RNA-mRNA duplex formation. Our results suggest that at least part of the inhibitory effect is at the posttranscriptional level.

Base Sequence↗
PubMed1990

Macrophage-tropic strains of human immunodeficiency virus type 1 utilize the CD4 receptor.

To characterize the role of CD4 in human immunodeficiency virus type 1 (HIV-1) infection of macrophages, we examined the expression of CD4 by primary human monocyte-derived macrophages and studied the effect of recombinant soluble CD4 and anti-CD4 monoclonal antibodies on HIV-1 infection of these cells. Immunofluorescence and Western blot (immunoblot) studies demonstrated that both monocytes and macrophages display low levels of surface CD4, which is identical in mobility to CD4 in lymphocytes. Recombinant soluble CD4 and the anti-CD4 monoclonal antibody Leu3a blocked infection of macrophages by three different macrophage-tropic HIV isolates, and the cytopathic effects of HIV-1 infection were similarly prevented. Dose-response experiments using a prototype isolate which replicates in both macrophages and T lymphocytes showed that recombinant soluble CD4 inhibited infection of macrophages more efficiently than in lymphocytes. These results indicate that CD4 is the dominant entry pathway for HIV-1 infection of macrophages. In addition, recombinant soluble CD4 effectively blocks HIV-1 infection by a variety of macrophage-tropic strains and thus has the potential for therapeutic use in macrophage-dependent pathogenesis in HIV disease.

Antibodies, Monoclonal↗
PubMed1990

Disintegration of mercury disc cells in simulated gastric juice: implications for management of disc cell ingestion.

The disintegration of charged alkaline mercury button cells in simulated gastric fluid over a 24 h period has been studied. The integrity of the cells and the amount of mercury that can leak out of them were assessed. The cells raised the pH of the incubating solutions. Disruption was seen in five out of 18 cells tested in 0.1 mol/L hydrochloric acid and one out of nine in 0.9% saline. Five of the six disrupted cells were made by the same manufacturer. Major leakage of mercury only occurred after complete disintegration of the cells. The implications of these findings for the management of patients who have ingested mercury-containing button cells are discussed.

Animals↗
PubMed1988

High resolution analysis of ground foot reaction forces.

A new system of hardware and software has been designed for quantitative high resolution analysis of ground foot pressures during stance and gait. In the system, a large photoelastic sheet is used as the transducer and a computerized video system for analysis and display. This system offers a larger active surface at higher resolution and at lower cost than any other system heretofore described. It will be used to predict diabetic plantar ulceration as well as to detect anatomic and motor defects affecting the feet.

Computer Graphics↗
PubMed1976

Protocol management of male genitourinary infections.

As part of a demonstration study, 567 male patients presenting to a "walk-in" clinic with common genitourinary complaints were interviewed by health assistants guided by a protocol. Independent examination of 19 patients by a health assistant and a physician formally demonstrated that the health assistants could collect the clinical data accurately. Forty-four patients were then randomly chosen to be examined, diagnosed and treated either by a health assistant guided by the protocol and supported by an available physician, or only by a physician. Using medical records and a follow-up interview, we assessed the thoroughness of the medical record, adequacy of diagnosis and treatment, symptom relief, patient satisfaction and patient education: the health assistant-protocol system proved as safe and effective as the MD-only system, and the health assistants were able to manage 68% of patients without involving the physician. The study suggests that briefly-trained health assistants may help save physician and nurse time, and that the development of protocols can help set standards for the medical management of defined problems while providing a mechanism for rapidly creating a complete medical record which can be easily audited for conformance with standards.

Adolescent↗
PubMed1975

Protocol management of dysuria, urinary frequency, and vaginal discharge.

A proctocol to be administered by nurses for the management of dysuria, frequent urination, and vaginal discharge was validated. In a randomized, controlled trial, 146 women were seen by both nurse and physician and then assigned to either the nurse-proctocol treatment plan or the physician treatment plan. The clinical data collected by the nurse showed no important differences from the physicians' data. The protocol recommended that 89 percent of the patients be sent home without seeing the physician. The physicians agreed with the protocol-recommended disposition in all but two cases. All patients with complications were appropriately referred to the physician. In follow-up, more than 95 percent of both groups reported symptomatic improvement, and repeat urine cultures were negative. We conclude that the protocol can be accurately administered, makes sound recommendations, is safe, and efficiently saves physician time.

Adolescent↗