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J Parkin

Publications and source records attributed to J Parkin.

At least 37 records · Page 2Linked to original sources
PubMed1993

Double-staining artefact observed in certain individuals during dual-colour immunophenotyping of lymphocytes by flow cytometry.

An unusual double-staining artefact has been repeatedly observed in certain individuals (both HIV-positive and healthy laboratory controls) during 2-colour immunophenotyping of lymphocytes by flow cytometry after red cell lysis. This artefact can falsely suggest co-expression of CD4 and CD8, as well as some of the other monoclonal antibody pairs commonly used in the typing of lymphocytes. It is caused by a serum factor associated with the ammonium-sulphate-precipitated and gamma-globulin fractions. It appears to be fairly common in the population (being found in 6 out of 105 of our healthy laboratory controls and in 42 out of 247 of our HIV-1 seropositive subjects); it may be genetically determined, but may be acquired in some. It is a potential source of error in lymphocyte immunophenotyping, which can be avoided by simple adjustments to the recommended techniques.

Antibodies, Monoclonal↗
PubMed1993

Iron overload in multiply transfused patients who are HIV seropositive.

AIMS: To assess histologically the amount of iron deposited in liver biopsy specimens from HIV positive patients; and to perform estimations of liver iron on tissue from patients with an increase in parenchymal stainable iron. To correlate the amount of blood transfused and the degree of iron overload. METHODS: Liver biopsy specimens (n = 120) from 109 HIV positive patients, 74 of whom had AIDS, were examined retrospectively and the amount of iron, as visualised with Perls's stain, was graded. Fibrosis was assessed using connective tissue stains. Estimations of liver iron were performed on tissue retrieved from paraffin wax blocks in cases with histological grade 3 or 4 iron overload. The amount of blood transfused before liver biopsy was determined from the notes for each patient. RESULTS: Fifteen of the 120 liver biopsy specimens had significantly increased amounts of iron in their hepatocytes, as assessed histologically, and this was confirmed in seven cases by measurement of liver iron. There was a close correlation between the amount of blood transfused and the degree of iron overload. In the initial biopsy specimens only one case showed portal tract expansion. Three of the five patients who had repeat biopsies, however, showed progressive fibrosis. CONCLUSION: Multiply transfused HIV positive patients may develop clinically important iron overload and are at risk of developing progressive fibrosis. Superimposed liver disease, especially viral hepatitis, in these high risk patients may exacerbate the effects of the iron overload.

Adult↗
PubMed1993

Lymphoproliferative process with natural killer cell phenotype. Histopathologic, ultrastructural, and surface marker observations.

We describe the clinical, structural, and immunophenotypic characteristics of a lymphoproliferative process characterized by persistent thrombocytopenia and prominent involvement of the spleen and, to a lesser degree, the liver. The proliferating cells lacked cytoplasmic azurophilic granules by light microscopy and on ultrastructural examination displayed prominent interdigitating cell processes and did not contain parallel tubular arrays. Immunophenotypically, the cells displayed markers of true natural killer cells (positive CD2, CD56, CD45, CD7, CD16, and CD33). No involvement of peripheral blood or bone marrow was detected. This case represents a proliferation of true natural killer cells probably arising in the spleen. The relationship of this process to other lymphoid proliferations at different sites with true natural killer cell or natural killer-like activity is unknown.

Adult↗
PubMed1991

Telephone use by patients fitted with the Ineraid cochlear implant.

A survey of telephone use by 66 patients fitted with the Ineraid cochlear prosthesis revealed that 51% initiate telephone calls (most calls are to family or friends) and that 66% answer the telephone. Of the patients who answer the telephone, 49% indicated that they could identify the gender and/or age of the caller most of the time, 27% could identify a familiar caller most of the time, and 48% indicated that they could understand a conversation most of the time if speaking to a familiar speaker about a familiar topic. Understanding dropped rapidly as the speaker and topic became unfamiliar.

Cochlear Implants↗
PubMed1991

Eosinophilic leukemia: a myeloproliferative disorder distinct from the hypereosinophilic syndrome.

Evidence to support the existence of eosinophilic leukemia (EL) as an autonomous eosinophilic proliferation analogous to other myeloproliferative disorders has been somewhat confusing. Partially obscuring the existence of EL as a distinct entity is the proposal that EL merely represents a clinically aggressive form of hypereosinophilic syndrome. This report details the clinical and pathologic findings in a case of EL. The presence of trisomy 8 and trisomy 21; morphologic, cytochemical, and ultrastructural findings of granular abnormalities and nuclear/cytoplasmic dysynchrony; and a clinical course similar to that of other myeloproliferative disorders support the existence of EL as a rare but distinct entity within the spectrum of myeloproliferative diseases.

Adult↗
PubMed1990

Pitch scaling and speech understanding by patients who use the Ineraid cochlear implant.

Pitch scaling was assessed for 10 normal-hearing listeners and 8 patients who use the Ineraid multichannel cochlear implant. For two patients who were excellent users of the prosthesis, pitch increased over a wide range of frequencies (100 Hz to 2333-3000 Hz). For three patients who were above average users of the prosthesis, pitch increased with frequency over a smaller range (100 Hz to 1200-2300 Hz). For three patients who demonstrated poor word recognition ability, pitch increased with frequency over a very small range (100 Hz to 600-1000 Hz). These results suggest that differences in speech understanding among patients who use the Ineraid may be accounted for, in part, by the range of pitch available through the implant.

Acoustics↗
PubMed1990

Acoustic cues for consonant identification by patients who use the Ineraid cochlear implant.

Ten patients who use the Ineraid cochlear implant were tested on a consonant identification task. The stimuli were 16 consonants in the "aCa" environment. The patients who scored greater than 60 percent correct were found to have high feature information scores for amplitude envelope features and for features requiring the detection of high-frequency energy. The patients who scored less than 60 percent correct exhibited lower scores for all features of the signal. The difference in performance between the two groups of patients may be due, at least in part, to differences in the detection or resolution of high-frequency components in the speech signal.

Adult↗
PubMed1990

Protracted enteric cryptosporidial infection in selective immunoglobulin A and saccharomyces opsonin deficiencies.

Chronic cryptosporidial infection in man usually occurs in those who are immunocompromised. We report a patient with a one year history of bowel symptoms resulting from persistent cryptosporidial infection of the colon. Investigations showed underlying selective IgA and saccharomyces opsonin deficiencies but no evidence of cell mediated immune dysfunction. Both selective immunoglobulin A and opsonin deficiencies are relatively common in the general population and may be a cause of susceptibility to persistent cryptosporidial infection.

Chronic Disease↗
PubMed1987

HIV antigen testing.

Explore the source record for details and available documents.

AIDS-Related Complex↗
PubMed1987

Transient atypical lymphocytosis in patients with emergency medical conditions.

Lymphocytosis in older adults is unusual and frequently indicates chronic lymphocytic leukemia or other lymphoproliferative disorder. This report describes 73 patients, aged 43 to 93 years, who presented with emergency medical conditions and who had absolute lymphocytosis, with absolute lymphocyte counts ranging from 4.1 to 12.9 X 10(9)/L (4100 to 12,900/mm3). The lymphocytosis was characterized morphologically by atypical lymphocytes and was transient, followed, in most instances, by a neutrophilia. Most of the patients presented with serious cardiac conditions; the remaining presented with other critical disorders including status epilepticus and traumatic injuries. The mortality rate was high (50%). The lymphocytosis in some patients was probably secondary to the administration of epinephrine. The lymphocytosis in those not receiving epinephrine may have represented a physiologic reaction to severe stress.

Adult↗
PubMed1982

Mucopolysaccharidosis type VII. A morphologic, cytochemical, and ultrastructural study of the blood and bone marrow.

The morphologic, cytochemical, and ultrastructural pathology of the blood and bone marrow of an infant with Mucopolysaccharidosis Type VII (MPS VII) is reported. The neutrophils, monocytes, basophils, and eosinophils contained prominent granulation of the Alder-Reilly type. The lymphocytes, plasma cells, osteoblasts, and macrophages contained cytoplasmic inclusions surrounded by clear vacuoles. Cytochemically, the granulocytes, monocytes, and lymphocytes were negative for beta-glucuronidase, negative or weakly metachromatic with toluidine blue, and positive for acid phosphatase. Macrophages were negative with toluidine blue. A normal staining pattern was present with myeloperoxidase and periodic acid-Schiff (PAS). Ultrastructural studies showed abnormal vacuoles in neutrophils, basophils, eosinophils, monocytes, lymphocytes, plasma cells, and macrophages. Occasional vacuoles contained Ruthenium Red positive material and confirmed the presence of acid mucopolysaccharide in these cells. This report confirms previously described abnormalities in peripheral blood cells in MPS VII, demonstrates additional abnormalities in bone marrow, and reports cytochemical reactions in leukocytes in MPS VII.

Adult↗
PubMed1982

Acute promyelocytic leukaemia: a study of 39 cases with identification of a hyperbasophilic microgranular variant.

Thirty-nine cases of acute promyelocytic leukaemia (APL) were divided into two morphological subgroups, typical hypergranular APL (31 cases) and microgranular APL (eight cases, 21%). The leukaemic cells in the microgranular APL cases were characterized by striking nuclear folding or lobulation; granulation was present in most of these cells but was less abundant and finer than in typical APL. In three microgranular APL cases a distinctive small leukaemic promyelocyte with unusual nuclear lobulation and deeply basophilic cytoplasm containing few or no visable granules was the predominant leukaemic cell. This small hyperbasophilic promyelocyte was also present as a minor population of cells in the other five microgranular APL case and in 28 of the 31 typical APL cases. Ultrastructurally the most abundant promyelocytes in microgranular APL had smaller and usually fewer granules than in typical APL; other characteristic ultrastructural features of APL were found with equal frequency. The median blood leucocyte count was significantly higher in microgranular APL, 83.0 x 10(9) x 10(9)/l, than in typical APL, 1.8 x 10(9)/l (P less than 0.01). The median duration of complete remission (CR) for microgranular APL, 6.5 months, was shorter than the 21 + month median CR for typical APL. The morphological characteristics of microgranular APL may mimic those of myelomonocytic leukaemia; however, the presence of cells with multiple Auer rods, large inclusions of Auer-like material and the small hyperbasophilic promyelocytes are important distinguishing features. In equivocal cases cytochemistry, electron microscopy and cytogenetic studies may verify the diagnosis.

Adolescent↗