Search PubMed⌕ Search

Biomedical subjects

J R Allen

Publications and source records attributed to J R Allen.

At least 109 records · Page 6Linked to original sources
PubMed1987

Isolation and characterization of salivary antigens from the female tick, Dermacentor andersoni.

The salivary glands of ixodid ticks are complex organs which are known to contain the antigens responsible for tick resistance in animals. We have identified a large number of proteins from salivary gland extracts (SGE), at least some of which are immunologically recognized by tick resistant animals and which are therefore presumed to be secreted salivary components. During the 6 to 10 day feeding process, a number of these antigens alter in concentration according to individual kinetics, and some of these changes correlate with the kinetics of skin test reactivity of SGE obtained at different times throughout the feeding period. By use of immunoaffinity chromatography we have isolated large quantities of many of the salivary antigens (SGA) contained in SGE, and found that they contain several esterase activities. SGA stimulates both immediate and delayed skin reactions in tick resistant guinea-pigs, and these reactions are about 200-fold more intense, per unit protein, than those elicited by SGE. The skin reactions to SGA are basophil-mediated and have many features in common with the cutaneous basophil hypersensitivity reactions of tick resistant animals. The demonstrated antigenic complexity of the glands may have profound implications for attempts to develop anti-tick vaccines, as it may eventually be found that candidate vaccines will have to incorporate more than one tick antigen in order to be effective.

Animals↗
PubMed1987

Association of eosinophilic myositis with an unusual species of Sarcocystis in a beef cow.

The carcass of a mature cow had numerous, disseminated lesions typical of eosinophilic myositis. To elucidate the nature and possible cause of the lesions, histological sections were examined by light microscopy and selected areas were removed and processed for electron microscopy. The lesions were granulomatous in nature. Each granuloma contained at its centre an intact or ruptured sarcocyst associated with degenerate muscle fibers. Surrounding this was a layer of epithelioid cells and an intense accumulation of inflammatory cells, most of which were eosinophils. The primary cyst wall of the sarcocysts in these granulomas consisted of hair-like protrusions that featured many unusual electron-dense bodies. Sarcocysts with ultrastructures characteristic of Sarcocystis cruzi and Sarcocystis hirsuta were also present in muscle from the same animal, but these sarcocysts lacked any associated cellular responses. The eosinophilic myositis in this case appeared to be associated with sarcocystosis of an unknown species. Possibly, the inflammatory reaction was due to the host-parasite interaction in an unusual host.

Animals↗
PubMed1987

Risk of AIDS for recipients of blood components from donors who subsequently developed AIDS.

Reported cases of acquired immunodeficiency syndrome (AIDS) in San Francisco as of March 31, 1986, include 92 individuals who had donated blood subsequent to 1978. Their donated blood components had been transfused into 406 different recipients. The current status of 336 of these recipients was ascertained as of April 1, 1986. Of these, 223 had died at the time of our first contact, almost all as a result of the condition for which they were transfused. Seven had developed AIDS; five of these died, two before entry into the study and three subsequently. Forty-six additional living recipients were interviewed and evaluated. Seven had the AIDS-related complex, 18 had antibody to the human immunodeficiency virus (HIV) but were otherwise healthy, and 19 had no detectable anti-HIV. Two had risk factors other than transfusion. The frequency of infection of the recipient decreased as the time interval between transfusion and the diagnosis of AIDS in the donor increased. This information should be useful when counseling patients who have been transfused with blood components from donors later found to be infected with HIV.

Acquired Immunodeficiency Syndrome↗
PubMed1986

Laboratory and epidemiologic evaluation of an enzyme immunoassay for antibodies to HTLV-III.

The enzyme immunoassays (EIAs) for antibody to human T-cell lymphotropic virus type III (HTLV-III) were rapidly adopted for screening donated blood and plasma. To evaluate the significance of a positive EIA reaction, test performance was examined in a blood bank screening program. Specimens were tested by EIA, Western blot assay, and HTLV-III/lymphadenopathy-associated virus (LAV) culture. The EIA was positive in 0.25% of 67 190 blood donations. Specimens were categorized and 57.3% had low (weak) reactivity, 12.7% had moderate reactivity, and 30.0% had high reactivity. Highly reactive specimens were strongly associated with a positive Western blot or culture (86.7%) in contrast to moderately and weakly reactive specimens (1.9%). Twenty-five of 29 donors interviewed with a highly reactive EIA had risk factors for HTLV-III/LAV infection. Risk factors were not identified for 74 of 75 interviewed donors with specimens of lower reactivity. The minimum calculated specificity was 99.82%. The use of the HTLV-III EIA has virtually eliminated the use of blood and plasma from HTLV-III/LAV infected donors.

Adult↗
PubMed1986

Allogeneic bone marrow transplantation at Christchurch 1979-1985.

Twelve bone marrow transplants have been carried out at Christchurch since 1979 in five patients with aplastic anaemia and seven with acute leukaemia. Five patients are currently alive at 77, 69, 63, 45, and seven months post-transplant. Acute and chronic graft versus host disease have been major problems and its clinical features and management are described. Long term follow-up data is presented on the four patients currently alive at between three to six years post-transplant. The practical problems we have experienced by carrying out bone marrow transplants without special funding have been considerable and the implications of this are discussed.

Adolescent↗
PubMed1986

HTLV-III/LAV infection in hemodialysis patients.

Twenty-five (4.8%) of 520 hemodialysis patients were seropositive for antibody to human T-cell lymphotropic virus type III/lymphadenopathy-associated virus (HTLV-III/LAV) by enzyme immunoassay. Four had high reactivity on enzyme immunoassay and positive results of Western blot tests, and one of the four had a positive culture. The remaining 21 seropositive patients had low reactivity on enzyme immunoassay, negative results of Western blot tests, and negative cultures. All had received blood transfusions and 19 had antibodies to antigens associated with the H9 cell line used to propagate HTLV-III for serological tests. We found that HTLV-III/LAV was not transmitted in the dialysis centers. Frequent blood transfusion places dialysis patients at risk for HTLV-III/LAV infection, but may more commonly lead to false-positive results of enzyme immunoassay tests.

Acquired Immunodeficiency Syndrome↗
PubMed1986

Are there compartment syndromes in some patients with idiopathic back pain?

Palpable rigidity of the epaxial (paraspinal) muscles, lordotic flattening, and spinal flexion accompanying back pain generally are ascribed to epaxial muscle spasm. However, palpable rigidity without muscle spasm occurs in compartment syndromes and epaxial muscle contractions extend the spine, increasing lordosis. Epaxial compartment syndromes are proposed as a possible cause of palpable rigidity, lordotic flattening, and spinal flexion accompanying idiopathic back pain. This article demonstrates the following: existence of an epaxial compartment by latex and dye injections; simulation of epaxial compartment syndromes in unembalmed cadavers by saline injections; and a "Bourdon tube effect" producing spinal flexion with lordotic flattening during epaxial compartment syndrome simulation in embalmed cadavers. In addition, resting and exercising epaxial compartment pressures were measured in 18 normal volunteers with a slit catheter.

Aged↗