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Biomedical subjects

R I Harris

Publications and source records attributed to R I Harris.

At least 19 recordsLinked to original sources
PubMed1992

Comparison of CLA with BPT, SPT, and RAST in children with asthma.

Bronchial provocation tests (BPT) with allergen extracts were performed in 82 children with asthma, and the results were compared with the chemiluminescent assay (CLA), the radio-allergo-sorbent-test (RAST) and skin prick test (SPT). It was found that CLA matched BPT with a concordance of 87% (77-93%), RAST with a concordance of 74% (64-83%) and SPT with 80% (70-88%). Most often, CLA and RAST gave similar results, although their classes did not match precisely.

Adolescent↗
PubMed1991

A study of changes in red cell volume and haemoglobin concentration during phlebotomy induced iron deficiency and iron repletion using the Technicon H1.

The recently introduced Technicon H1 analyser uses an improved optical principle to measure the size and haemoglobin concentration of erythrocytes. We have made a serial study of ten patients undergoing phlebotomy to induce mild iron deficiency. The instrument showed the early development of anisohypochromia with subsequent fall in the mean cell haemoglobin concentration (MCHC). Cell volume was preserved until relatively late and during early iron deficient erythropoiesis cell volume would appear to be maintained at the expense of haemoglobin concentration. The Technicon H6000 (conventional technology) used in parallel produced contrasting results indicating anisomicrocytosis with preservation of cell haemoglobin concentration until relatively late. Five cases of severe iron deficiency treated with iron were similarly studied and showed comparable changes on both instruments, with characteristically bimodal cell volume histograms and large increases in red cell distribution width. Our results indicate that the new generation of instruments will generate red cell data of additional clinical value.

Anemia, Hypochromic↗
PubMed1991

Statistical problems in assessing the true value of new in vitro diagnostic tests, with special reference to the chemiluminescent assay (CLA, MAST).

By virtue of familiarity and usage over many years, diagnostic tests may become established and be regarded as infallible "Gold Standards". In the case of allergic disease no test except perhaps allergen challenge can ever precisely reflect the clinical disease at the actual site of the allergic reaction. Thus when a new test is introduced there are no fixed values available for statistical comparison when directly comparing established tests with more recent additions. This is illustrated by many articles comparing the new multiple allergosorbent test system (CLA, MAST) which is a chemiluminescent assay, to other previously established tests. The major reports on CLA in the diagnosis of allergy are here discussed and summarized. Most trials have compared the accuracy of CLA with clinical history, with the skin prick test (SPT), the universally used in vivo method, or with RAST, the most common in vitro diagnostic method. CLA performed similarly to SPT and most CLA and RAST results matched; nevertheless in statistical analyses the problems of comparing diagnostic methods without a Gold Standard against which to judge become obvious-if two fallible methods disagree, which is correct? These statistical problems are discussed as well as other difficulties, such as the impact of the use of different allergen sources and the differing prevalence of allergies in the various test populations analysed.

Biometry↗
PubMed1991

Relationships between skin prick test, radioallergosorbent test, and chemiluminescent assays in allergic children.

The results of skin prick tests (SPT), radioallergosorbent tests (RAST), and multiple chemiluminescent tests (DHS-CLA) to grass mix, parietaria, D. farinae, and D. pteronyssinus were evaluated in 43 allergic children. All CLA tests had valid positive and negative control threads. Chemiluminescent assays class 4 matched with RAST class 3 and/or 4 and CLA class 3 with RAST class 2. The D. farinae, D. pteronyssinus, and grass results obtained with CLA, RAST, and SPT were investigated by principal components analysis that showed a good association between different methods of measuring allergenicity. The results of the present study confirm that DHS-CLA is an effective "in vitro" method for the detection of IgE-allergen specific antibody.

Allergens↗
PubMed1990

Immunotherapy of tree pollen allergy with a modified alginate conjugated birch pollen extract compared to an aluminium adsorbed extract.

The safety and efficacy of two birch pollen extracts, one chemically conjugated to alginate (Anjuvac) the other adsorbed to aluminium hydroxide (Alutard), were investigated in an open multicentre comparative study of 63 birch pollen allergic patients. Both extracts decreased the nasal symptoms during the birch pollen season. The changes in specific IgE and IgG were much the same in both treatment groups. The adverse reactions recorded were mild in both groups, but more frequent in the Anjuvac group, probably because of a more aggressive dose schedule though there were twice as many asthmatics in the Anjuvac group. The two investigated allergen extracts were useful alternatives for immunotherapy.

Adolescent↗
PubMed1989

Treatment of refractory and relapsed non-Hodgkin's lymphoma with ifosfamide, methotrexate and etoposide.

The combination of ifosfamide, etoposide and methotrexate was evaluated in 22 patients with non-Hodgkin's lymphoma (NHL) whose disease had relapsed or was resistant to first-line adriamycin-containing treatment. Only 4 of the 22 patients underwent remissions, 3 of which were complete and 1, partial. Two of the complete remissions occurred in patients with "high-grade" histology who received IMVP-16 after first-line treatment had induced only a partial remission. Bone marrow suppression was the limiting toxicity of this regime, which may be of value in the salvage therapy of selected patients with NHL.

Adult↗
PubMed1989

Gentamicin and low dose piperacillin in febrile neutropenic patients.

One hundred and twenty-seven febrile neutropenic patients were randomized to receive empirical antibiotic therapy with intravenous gentamicin and 12 g/day or 8 g/day piperacillin. Despite a high incidence of Hickman catheter infections by antibiotic-resistant bacteria, there was an overall response in 56% of patients and no difference in the numbers responding to each antibiotic regimen. In addition, the duration of fever was not significantly different in the two groups of patients. The majority of the unresponsive patients responded to the addition of further antibiotics and there were only two infection related deaths. The results suggest that high dose antibiotics are not essential for the initial empirical therapy in febrile neutropenic patients.

Adult↗
PubMed1989

The use of the technicon H1 in the diagnosis of hereditary spherocytosis.

Blood samples from 21 patients with confirmed hereditary spherocytosis (HS) were studied using the Technicon H1 blood counter. Nine patients had had a splenectomy and 12 were unsplenectomized. In the latter, the means of MCHC and RDW as measured by the H1 were significantly higher than results obtained using the Technicon H6000. Furthermore, spherocytes were recognizable in all of the H1 histograms of red cell size and Hb concentration as distinctive hyperchromic and microcytic tails, and the HDW (Hb distribution width) was consistently elevated. In the splenectomized patients, although the mean MCHC and RDW results were significantly higher as measured by the H1, it was not possible to recognize any abnormalities in the red cell histograms, and the HDW results were normal. Two of 75 apparently normal blood donors showed very small tails of hyperchromic cells, but in neither was this sufficient to disturb the MCHC, RDW or HDW parameters, and confusion with an unsplenectomized case of HS would be very unlikely. The H1 appearances of HS are so specific that the measurement of osmotic fragility will seldom be necessary.

Blood Cell Count↗
PubMed1989

A double-blind study of hyposensitization with an alginate conjugated extract of D. pteronyssinus (Conjuvac) in patients with perennial rhinitis. 1. Clinical aspects.

The efficacy of hyposensitization with a standardised extract of Dermatophagoides pteronyssinus (D. pteronyssinus) conjugated to alginate and containing known amounts of antigen P1 (Conjuvac) was tested in a double blind, placebo controlled, multi-centre study in 66 adult patients with perennial rhinitis. Patients received 11 weekly injections of increasing concentrations of Conjuvac containing from 56 x 10(1) to 448 10(3) IU D. pteronyssinus or placebo injections of the alginate diluent to some of which 5 micrograms of histamine has been randomly added. This was followed by 15 monthly injections of Conjuvac or placebo. The severity of nasal blockage, sneezing and rhinorrhoea was recorded twice daily in a diary and visual analogue assessments (VAS) made at each clinic visit. Nasal provocation testing (NPT) was performed with increasing concentrations of the same extract of D. pteronyssinus as used in the hyposensitization injections, and changes in nasal airways resistance measured by passive anterior rhinomanometry. VAS was recorded and NPT was performed on entry to the study and after the fifth, ninth and final monthly injection. Conjuvac injections were well tolerated. Large local reactions (greater than 5 cm) occurred within 30 min in only 1% of patients but later in 23%. No systemic reactions or anaphylaxis occurred within 30 min of injections, but urticaria or worsening of asthma and rhinitis was reported later in 3% of patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Adjuvants, Immunologic↗
PubMed1988

An epidemiological study of atopy in children.

A sample of 930 children, between 9 years and 15 years old from six Italian towns, were studied. Their family history of allergy, personal allergy and medical history, current allergy symptoms, exposure to environmental allergens, feeding as infants, and their parents' occupations were recorded. They were skin-prick tested (SPT) with a range of common allergens. A subject was defined as atopic if at least one SPT caused a weal greater than 3 mm diameter. The association between the recorded information and atopy was investigated by logistic multiple regression. Atopy was positively associated with: high density housing; medium or high exposure to environmental allergens; a history of rhinitis, asthma or atopic eczema; male gender; and a history of breastfeeding. It was independent of infectious diseases, vaccinations and operations, social class and family history. Thus, there was no evidence of a genetic factor in atopy, other than sex.

Adolescent↗
PubMed1988

Dose response curve of allergen and histamine in skin prick tests.

Twenty-six Dermatophagoides pteronyssinus (D.pt.) sensitive subjects were skin prick tested in duplicate with 15 concentrations of D.pt. ranging from 0.0018 to 17.8 mg/ml, 15 concentrations of the major allergen of D.pt., antigen P1, ranging from 0.0002 to 1.88 mg/ml and 15 concentrations of histamine dihydrochloride solution ranging from 0.048 to 114.0 mg/ml. Weal areas and concentrations were transformed by taking logs and linear and non-linear regression curves fitted, allowing for confounding variables, such as subject, and interactions. The weal areas over all concentrations fitted "S" shaped curves with essentially straight central portions, parallel between materials, with differences between subjects but parallel within subjects. The dose response curves of P1 and D.pt. were coincident when the concentrations were adjusted to allow for differences in potency. The concentrations of allergen and histamine commonly used for standardisation purposes will give weals that can be plotted along a straight line, but at higher and lower concentrations the response will tail off. This accounts for previously ambiguous results. Standardisation of allergens using 10 mg/ml histamine is preferable to 1 mg/mg.

Adult↗
PubMed1987

Empirical treatment of febrile, neutropenic patients with tobramycin and latamoxef.

One hundred and two febrile episodes in neutropenic patients were treated with intravenous tobramycin and latamoxef. After 48 h latamoxef at 6 g day-1, patients were randomized to continue this regimen or latamoxef at 3 g day-1. Infections responded to these regimens in 67% and 71% of patients, respectively. Two-thirds of the infections which failed to respond were due to coagulase-negative staphylococci in Hickman catheters, a trend which may necessitate the inclusion of additional antibiotics in future empirical regimens. Prolonged prothrombin times due to antibiotic therapy were seen in nine patients but there was only one episode of bleeding and this responded quickly to treatment with vitamin K and fresh frozen plasma. In 35 patients, coagulopathy was present before antibiotics were started, and these cases also responded to vitamin K. The study shows that the response to tobramycin and latamoxef is comparable to other broad-spectrum antibiotic regimens and that a reduction in the dose of latamoxef after 48 h treatment may safely permit cost savings.

Agranulocytosis↗
PubMed1986

Pulmonary embolism associated with self-administration of mercury.

We report the case of a young female patient presenting with a clinical picture of pulmonary embolism, in whom widespread deposits of metallic mercury were demonstrated throughout both lungs and in a lesion on the wrist. These resulted from intravenous injection of mercury by the patient in a suicide attempt.

Adult↗