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Biomedical subjects

R Duff

Publications and source records attributed to R Duff.

At least 19 recordsLinked to original sources
PubMed2005

Costs of running a universal adolescent hepatitis B vaccination programme.

In the first UK study to examine feasibility and acceptability of universal adolescent hepatitis B vaccination, the costs associated with the administration and uptake (80.2 and 89.3% for three doses and at least two doses, respectively), of a three-dose regimen in pupils in Glasgow schools (2001/2002) were measured. These data were used to estimate the economic outlay for the delivery of a routine, ongoing three-dose and two-dose hepatitis B vaccine programme in schools. Vaccine, accounting for almost 70% of the overall costs, was the largest cost item for both the pilot and routine programmes, using either regimen. However, the ongoing, two-dose regimen was the cheapest option in this analysis, irrespective of vaccine price. Cost data from this study may be useful for other countries wishing to implement a similar programme.

Adolescent↗
PubMed2005

A new dominant distal myopathy affecting posterior leg and anterior upper limb muscles.

OBJECTIVE: To report a dominant, slowly progressive early onset distal myopathy with sparing of the tibialis anterior. METHODS: Twelve affected and two possibly affected members from an Australian kindred were examined and investigated by EMG, imaging studies, histopathology, and genetic analysis. RESULTS: Affected patients had a slowly progressive condition with symmetric, distal weakness and wasting of the anterior upper and posterior lower limbs, with sparing of tibialis anterior, even in advanced disease. All patients remained ambulant and there was no evidence of cardiac or respiratory muscle involvement. Serum creatine kinase levels were either normal or mildly elevated. Imaging studies showed widespread involvement of the posterior and lateral leg compartments. Proximal muscles were radiologically abnormal only in advanced disease. Muscles that were mildly affected clinically appeared normal on imaging. EMG in nine patients showed widespread myopathic changes. Muscle histopathology in four patients showed either end stage muscle or nonspecific myopathic findings without inflammation or vacuoles. Microsatellite markers for distal myopathy loci were analyzed and all known distal myopathy phenotype genes and linkage regions were formally excluded by multipoint analysis. CONCLUSIONS: The affected patients in this kindred display a clinically distinct myopathy, with selective involvement of posterior lower and anterior upper limb muscles. The genetic analysis suggests the existence of one more distal myopathy locus.

Adolescent↗
PubMed2004

Determinants of universal adolescent hepatitis B vaccine uptake.

The UK is currently considering the introduction of universal hepatitis B vaccination. This study of determinants of vaccine uptake among school based adolescents shows that living in areas of high deprivation, commonly associated with injecting drug risk behaviours, was the most important factor, with statistically significant lower odds of receiving three doses. This was less pronounced for receipt of two doses. Thus, there are implications for future policy; if universal vaccination is approved, a licensed two dose schedule would be most appropriate in this setting.

Adolescent↗
PubMed2002

Universal hepatitis B vaccination of UK adolescents: a feasibility and acceptability study.

The feasibility of introducing universal hepatitis B immunisation was assessed by offering the vaccine to all 11-12 year old pupils in Greater Glasgow (approximately 10,800). Consent was received from 92% of the school roll, and 91.3%, 89.2% and 80.3% received at least 1, at least 2, and 3 doses respectively. The findings of this study constitute key evidence for the ongoing debate in the UK on hepatitis B vaccination.

Adolescent↗
PubMed1994

PHA induces IL-2 receptors on B-CLL cells and is a potential biological response modifier for the LIL-2-diphtheria toxin, DAB486IL-2.

DAB486IL-2 is an IL-2-diphtheria toxin conjugate which was developed to be specifically cytotoxic to cells bearing high affinity IL-2 receptors. The high affinity IL-2 receptor is a heterodimer comprising p55 and p75 subunits. While the p75 subunit appears to be ubiquitously expressed among the common North American leukemias and lymphomas, the p55 subunit is more restricted in its expression. To broaden the therapeutic relevance of the DAB486IL-2 we have sought physiologically feasible inducers of the p55 IL-2 receptor subunit. This report describes that PHA, in vitro, induces the p55 IL-2 receptor subunit on initially p55-negative B-CLL cells and converts toxin-insensitive leukemia cells to a toxin-sensitive state.

Diphtheria Toxin↗
PubMed1988

2',3'-Dideoxyadenosine is selectively toxic for TdT-positive cells.

The 2',3'-dideoxynucleosides (ddNs) are currently undergoing clinical evaluation as antiretroviral agents in HIV-infected individuals. When phosphorylated, the ddNs (ddNTPs) function as chain-terminating substrate analogues with reverse transcriptase, thereby inhibiting HIV replication. These nucleoside analogues can also inhibit, by chain-terminating additions, the primitive lymphoid DNA polymerase, terminal deoxynucleotidyl transferase (TdT). To determine the effect of possible intracellular chain-terminating additions of ddNMPs by TdT, we exposed a series of TdT-positive and TdT-negative cell lines to 2',3'-dideoxyadenosine (ddA), a representative ddN. At ddA concentrations 25-fold higher than required for inhibition of HIV replication, progressive dose-related cytotoxicity was observed in the TdT-positive cell lines. This was accentuated by the adenosine deaminase inhibitor Coformycin (CF), presumably by enhancing the intracellular generation of ddATP from ddA. A central role of TdT in mediating the ddA/CF cytotoxicity was suggested by studies in a pre-B-cell line rendered TdT positive by infection with a TdT cDNA-containing retroviral vector. After a 48-hour continuous exposure period to 250 mumol/L ddA and 30 mumol/L CF, 30% cell death was observed in the TdT-negative parental line, whereas 90% cell death was observed in the TdT-positive daughter line. Exposure of fresh TdT-positive leukemic cells to ddA/CF for 72 hours ex vivo resulted in cytotoxicity (six cases of acute lymphocytic leukemia [ALL]) while not affecting TdT-negative acute leukemic cells (six cases). We conclude that ddA/CF selectively damages TdT-positive cells, presumably by chain-terminating additions of ddAMP, and that this may have therapeutic relevance in TdT-positive malignant disease.

Cell Division↗
PubMed1987

Microencapsulated tumor assay: new short-term assay for in vivo evaluation of the effects of anticancer drugs on human tumor cell lines.

A new in vivo has been developed for evaluating the antitumor activity of chemotherapeutic drugs. The assay is based on a microencapsulation technology developed by Damon Biotech, Inc., Boston, MA, which makes it possible to encapsulate human tumor cells in small (about 1 mm in diameter) microcapsules with semipermeable membranes. Microcapsules containing human tumor cells were injected i.p. into nude or C57BL/6 mice and drugs were administered i.v. The microcapsules were recovered at various intervals following treatment and determinations of drug effects were made based on the differences in the number of tumor cells recovered from the treated and nontreated animals. Using this assay we found that (a) encapsulated tumor cells grew better in the in vivo system than in vitro under the conditions tested; (b) drugs crossed the capsular membrane and killed or inhibited the proliferation of tumor cells; and (c) the antitumor effect was consistent with the relative therapeutic efficacy of drugs or level of resistance of tumor cells detected by other in vitro or in vivo tests. The tumor microencapsulation assay offers several properties which make it attractive for use in new drug development: (a) the antitumor activity of drugs can be tested against human tumor cells under conditions which provide for three-dimensional growth and in vivo supply of nutrients; (b) the sensitivity of tumor cells can be assessed following exposure to drugs at concentrations which are achievable in vivo; (c) compounds requiring in vivo metabolic activation can be tested; (d) the effect of each drug injection can be quickly evaluated; (e) inhibition of tumor cell proliferation versus cytoreductive effects of drugs can be discriminated; (f) the test is applicable to virtually all histological types of human tumor cells; and (g) the tumor microencapsulation assay is a short-term, simple, and relatively inexpensive assay.

Animals↗
PubMed1987

Determination of L-buthionine-(S,R)-sulfoximine in plasma by high-performance liquid chromatography with o-phthalaldehyde derivatization and fluorometric detection.

The development of a high-performance liquid chromatography system for the analysis of L-buthionine-(S,R)-sulfoximine (BSO) in human plasma is described. o-Phthalaldehyde derivatization and fluorescence detection were used. The R- and S-BSO peaks were partially separated from each other and completely separated from the matrix components. The limit of detection for BSO was 2 micrograms/ml plasma.

Buthionine Sulfoximine↗
PubMed1981

A comparison of the fears of mildly retarded adults with children of their mental age and chronological age matched controls.

Twenty mildly retarded adults were matched for chronological age and sex with twenty non-retarded children using the Peabody Picture Vocabulary Test. All 60 subjects were given an 89-item Fear Survey Schedule with a three-point rating scale. Mildly retarded adults were more fearful in general and showed a more intense level of fear than their chronological age matched controls. However, they reported less overall fear than their mental age matched controls. Differences in type of feared objects or situations were reported between groups. The importance of understanding the degree and types of fear in promoting de-institutionalization in the retarded is stressed.

Adult↗
PubMed1978

Effects of experimental excision arthroplasty of the hip joint.

The experimental results are reported on a series of sheep in which unilateral hip excision arthroplasty was performed. These sheep were slaughtered at regular postoperative intervals. Radiography and histology were performed on the normal and excised hip joints of the experimental sheep to provide information of the formation of the pseudarthrosis that develops following excision arthroplasty. The efficiency of the false joint that develops is good, judged on a clinical basis. Continuous remodelling of the acetabulum and resected face was noted throughout the experimental period. A sequence of degenerative changes in the acetabular cartilage was observed followed by filling in of the acetabular favity with new bone. New bone also developed on the cemoral component of the pseudarthrosis in the form of osteophytes situated around the perimeter of the resected surface. Growth deformities of the contralateral, nonoperated limb were induced.

Acetabulum↗
PubMed1977

Long term results of excision arthroplasty of the canine hip.

An analysis has been made of the long term results of excision of the canine femoral head and neck. The most frequent postoperative findings include shortening of the operated limb and restricted movement of the hip pseudarthrosis. Although few dogs show lameness or pain in the operated hip, muscle atrophy is a frequent finding even after eight years. Difficulty in jumping and in climbing stairs are more commonly found postoperatively in the larger breeds of dog. Despite these noted abnormalities almost all owners expressed their satisfaction with the outcome of excision arthroplasty.

Animals↗