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Biomedical subjects

M J Hicks

Publications and source records attributed to M J Hicks.

At least 127 records · Page 7Linked to original sources
PubMed1986

The prevalence of cellular immunity to coccidioidomycosis in a highly endemic area.

Intradermal skin test reactivity to spherulin and coccidioidin and in vitro spherulin-induced lymphocyte transformation were used to assess cellular immunity in healthy subjects and patients with acute, self-limited coccidioidomycosis (cocci). The objectives of this study were to evaluate the relative sensitivities of the two assays in assessing cellular immunity to cocci, especially in long-term residents of an endemic area (Tucson) and, based on data from both assays, determine the prevalence of detectable cellular immunity to cocci in this highly endemic area. The lymphocyte transformation assay appeared to be more sensitive than the skin test in assessing long-term immune status, and the prevalence of detectable immunity to cocci in this highly endemic area was only 75% in long-term residents. This is much lower than previous prevalence estimates (90%) in other endemic areas. The absence of a demonstrable cell-mediated immunity may indicate either no prior antigen exposure (infection) or previous remote exposure with a diminished immune response (no reexposure to boost immunity). A possible explanation for the lower prevalence of immunity to cocci in this endemic area may relate to the increased urbanization of the Southwest in the past several years. Therefore, the clinical suspicion of acute cocci should not be restricted to recent arrivals to endemic areas.

Arizona↗
PubMed1985

A unique malignant T-cell lymphoproliferative disorder with neutropenia simulating hairy cell leukemia.

The association of neutropenia with an indolent chronic T-suppressor cell lymphoproliferative disorder (LPD) has been well documented. The morphologic features and course suggest that this is a benign disorder. The authors studied a 58-year-old man with a chronic T-cell LPD, splenomegaly, and neutropenia. Chromosomal analysis revealed multiple abnormalities which progressively increased in number as the marrow lymphocytosis became more prominent. Subsequently he developed small bowel infiltration. A splenectomy resulted in only brief improvement in the neutropenia. Immunopathologic examination of the spleen was consistent with a well-differentiated lymphocytic lymphoma of a mature peripheral T-cell type without subset specific markers. Granulocyte-monocyte colony (CFU-GM) formation from the patient's marrow was normal and not augmented by T-cell depletion. Neither the patient's splenic T-cells nor serum suppressed granulopoiesis. In contrast to previous T-LPD with neutropenia whose malignant nature has been questioned, the clinical, cytogenetic, and pathologic features and course in this case indicate a malignant lymphoid process which was effectively treated with chemotherapy. Although the histologic pattern of red pulp involvement simulated hairy cell leukemia, that diagnosis was excluded by this patient's clinical, morphologic, and cytochemical features.

Antibodies, Monoclonal↗
PubMed1985

Immune function in chronic active Epstein-Barr virus infection.

The spectrum of illness attributed to Epstein-Barr virus (EBV) includes patients with symptoms persisting for more than 1 year without any other obvious underlying disease. High titers of antibodies to EBV, either IgG antiviral capsid antigen or anti-early antigen, can be demonstrated. In this study, 13 patients diagnosed as having chronic active EBV infection were examined to determine aspects of their immunologic status. Morphological examination and fluorescent antibody analysis revealed no abnormalities in the phenotypes of peripheral blood white cells present in these patients. Compared to those from healthy control individuals, mononuclear cells from the patients showed a markedly depressed ability to produce both interleukin-2 and interferon after stimulation with mitogen and a phorbol ester. Studies of natural killer (NK) cell activity revealed that unfractionated mononuclear cells from patients with chronic active EBV infection were significantly lower in killing activity compared to the control group. Fractionation procedures to enrich for large granular lymphocytes resulted in an increase in NK activity for all individuals, but killing activity still remained slightly lower in the patients than in the control group. The dysfunctions which were found in patients with chronic active EBV infection may reflect a primary defect in natural immune functions of the patients predisposing them to a chronic or intermittent clinical disease rather than a self-limiting illness. Alternatively, the abnormalities detected in these experiments may be a result of the viral infection itself.

Adolescent↗
PubMed1985

Peripheral T-cell lymphoma: aggressive disease with heterogeneous immunotypes.

Eleven patients with mature or peripheral T-cell lymphoma (PTL), other than mycosis fungoides, were identified using an extensive battery of T- and B-cell markers. Eight cases had a histologic diagnosis of either diffuse large cell or mixed lymphoma, three of small cell type. All cases had one or more "mature" T-antigens and an absence of B- and immature T-antigens. Assessment of T-antigens included E-rosettes (Er), anti-Leu 1-7 and Tdt. The authors delineated striking heterogeneity of T-antigen expression: 9 different immunotypes in 11 cases. Subset T-antigen assessment indicated T-helper neoplastic cells in five cases and T-suppressor in two. The remaining four had universal T-antigens alone. Seven cases appeared to have "novel" T-phenotypes not corresponding to normal T-ontogeny phenotypes. Novel or idiosyncratic phenotypes may be a key characteristic of PTL. Since no single T-antigen, including Er and Er receptor (Leu-5), was expressed in all cases, a battery of monoclonal antibodies is necessary to detect PTL. Clinically, the authors found PTL unexpectedly aggressive, despite mature immunotype. Most patients were elderly (median age 69); all had extranodal disease with cutaneous involvement (six cases) most frequent. Responses to chemotherapy frequently proved transient, with median survival of nine months. A fulminant course was noted even with localized presentation. Clinical outcome suggests PTL requires new therapeutic strategies.

Adult↗
PubMed1985

Histopathology of the initial lesion of the root surface: an in vitro study.

An acidified gel system was used to produce artificial caries lesions in root surfaces. Radiopaque surface layers were found with 47% of the lesions. Demineralized bodies of the lesion and mineralized zones of banding were seen in all lesions when examined by microradiography. Cementum and dentin seemed to respond to the acid attack in a similar manner. Although artificial root lesions did not simulate natural root caries entirely, the acidified gel system resulted in a reproducible method that might give insight into initial lesion formation on root surfaces. This technique may be used for studying the physico-chemical process involved in the demineralization of root surfaces and for testing the effects of various agents in the prevention of root caries.

Aged↗
PubMed1985

Depth of penetration of in vitro root surface lesions.

An acidified gel system was used to produce artificial caries lesions in root surfaces and in enamel. The teeth were exposed to the gel system for two weeks and four weeks, after which the lesions were examined by polarized light microscopy and photographed by standardized techniques. The depths of penetration of the lesions were measured from these standardized photomicrographs. The lesions in root surfaces were deeper than those in enamel for all teeth. After two but not four weeks of exposure in the gel system, the lesions in the root surfaces of anterior teeth were deeper than those in pre-molars.

Aged↗
PubMed1985

Internal morphology of surface zones from acid-etched caries-like lesions: a scanning electron microscopic study.

Using scanning electron microscopic techniques, we compared the surface topography and internal surface morphology of acid-etched caries-like lesions of enamel with those of sound enamel and caries-like lesions of enamel. The results indicated that acid-etching of caries-like lesions of enamel yielded etching patterns similar to those previously described for sound enamel. The internal morphology of the acid-etched lesion indicated that porosities were created which may allow access to the subsurface demineralized area of the lesion and could prove beneficial in facilitating remineralization.

Acid Etching, Dental↗
PubMed1985

Oral fluid contamination of etched enamel surfaces: an SEM study.

The purpose of this in vitro study was to determine the effects of differing salivary contamination periods on the surface topography of etched enamel surfaces using SEM techniques. The results indicated that salivary contamination of etched enamel for 1 second or longer resulted in the formation of surface coatings that could not be removed by a water wash. It was concluded that should salivary contamination of an etched enamel surface occur, it would be necessary to repeat the etching procedure to ensure adequate bonding of a resin material.

Acid Etching, Dental↗
PubMed1985

Evidence for active Epstein-Barr virus infection in patients with persistent, unexplained illnesses: elevated anti-early antigen antibodies.

Forty-four patients, including 26 adults and 18 children under 15 years of age, were referred for evaluation of recurrent or persistent illnesses, with symptoms including pharyngitis, lymphadenopathy, fever, headaches, arthralgia, fatigue, depression, dyslogia, and myalgia. Thirty-nine patients were positive for Epstein-Barr virus antibody with antibody levels compatible with active infection for at least 1 year. Antiviral capsid antigen and anti-early antigen titers of patients were significantly greater (p less than 0.001) than age-group-matched controls. The frequency, number, duration, and patterns of symptoms, as well as patient sex, were compared by age in study patients seropositive and seronegative for Epstein-Barr virus. Illness patterns were not associated with changes in specific antibody titers or clinical findings. Lymphocyte phenotype and function analyses were done in 11 of the 39 patients positive for Epstein-Barr virus antibody; no consistent differences from normal were found. Only 1 of 32 patients had circulating interferon, in contrast to 7 of 7 patients with acute infectious mononucleosis. There were many adverse consequences of the illness. Epstein-Barr virus infection may not be self-limiting, and the virus may be associated with clinically recognizable illness other than infectious mononucleosis in children as well as in adults.

Adolescent↗
PubMed1985

Ultrastructural morphometric analysis of normal human lymphocytes stimulated in vitro with mitogens and antigens.

In the present study the authors attempt to experimentally produce the characteristic cerebriform appearance of Sézary cells from normal cells by stimulation in vitro with a variety of mitogens and antigens. Lymphocytes were stimulated with the mitogens phytohemagglutinin (PHA), concanavalin A, and pokeweed mitogen and the antigens spherulin, Candida, and herpes simplex virus Type I. In vitro blast transformation was measured in tritiated thymidine uptake microculture systems. Nuclear contours were morphometrically analyzed with the use of a computerized planimeter. An exhaustive search for Sézary-type cells did not reveal any nuclear profiles that were highly convoluted. The lowest form factor value obtained from the stimulated cultures was 0.14. This value represents 14% of a circle. All stimulated cultures analyzed morphometrically showed significant blast transformation. There was no correlation between the degree of stimulation and the nuclear contour values. An analysis of mean form factor values from ten separate lymphoid populations revealed that neither mitogens nor antigens had any effect on increasing the nuclear irregularity of lymphoid cells. One PHA-stimulated culture, in fact, had less irregular nuclear contours than the 3-day unstimulated control cells. The difference in these means was statistically significant (P less than 0.05). In addition, morphometric analysis of 73 published electron micrographs of human lymphoid cells from a variety of clinical and experimental conditions showing irregular nuclear contours revealed that only 5% had nuclei that were more irregular than the most convoluted nuclei analyzed from lymphocytes stimulated in vitro in the present study. The authors have shown that mitogen- and antigen-stimulated cells do not display the highly irregular nuclear outlines commonly seen in the Sézary syndrome and mycosis fungoides and emphasize the need for more objective analysis of Sézary-like nuclear profiles to determine their specificity.

Antigens↗
PubMed1984

Pseudonodular T cell lymphoblastic lymphoma.

T cell lymphoblastic lymphoma usually presents as a rapidly growing lymphoma with histologic features of a diffuse, poorly-differentiated small cell lymphoma with a high mitotic rate. This report describes a patient who presented with an aggressive small cell lymphoma that morphologically had a nodular pattern. Repeated biopsy and use of cell surface markers resulted in reclassifying the cell type as T cell lymphoblastic and in recognizing the original pattern as pseudonodular. The routine application of these immunologic techniques in patients with lymphoma may lead to more accurate diagnoses and improved treatment.

Adult↗
PubMed1984

A scanning electron microscopic and polarized light microscopic study of acid-etching of caries-like lesions in human tooth enamel treated with sodium fluoride in vitro.

Types of etching patterns and histological appearances were examined in acid-etched, NaF-treated caries-like lesions of enamel. Etching patterns similar to those for etched-sound enamel were found. Remineralization was limited to the surface zone and superficial portion of the body of the lesion following acid-etching of NaF-treated caries-like lesions.

Acid Etching, Dental↗