Biomedical subjects

Jeanine Bartlett

Publications and source records attributed to Jeanine Bartlett.

7 recordsLinked to original sources

PubMed2007

An in vitro model of the leukocyte interactions associated with granuloma formation in Mycobacterium tuberculosis infection.

The principal defense of the human host against a Mycobacterium tuberculosis infection is the formation of granulomas, organized collections of activated macrophages, including epithelioid and multinucleated giant cells, surrounded by lymphocytes. This granuloma can sequester and contain the bacteria preventing active disease, and if the granuloma is maintained, these bacteria may remain latent for a person's lifetime. Secretion of a variety of chemoattractant cytokines following phagocytosis of the bacilli by the macrophage is critical not only to the formation of the granuloma but also to its maintenance. To investigate this process of early granuloma formation, we developed an in vitro model composed entirely of human cells. Combining blood lymphocytes and autologous macrophages from healthy purified protein derivative skin test-negative individuals and mycobacteria resulted in the formation of small, rounded aggregate structures. Microscopic examination found macrophage-specific CD68(+) epithelioid macrophages and small round CD3(+) lymphocytes that in complex resembled small granulomas seen in clinical pathology specimens. Acid-fast staining bacteria were observed between and possibly within the cells composing the granulomas. Supernatants from the infected cells collected at 24 and 48 h and 5 and 9 days after infection were analyzed by a multiplexed cytokine bead-based assay using the Luminex 100 and were found to contain interleukin (IL)-6, IL-8, interferon-gamma and tumor necrosis factor-alpha, cytokines known to be involved in human granuloma formation, in quantities from two-fold to 7000-fold higher than supernatants from uninfected control cells. In addition, chemotaxis assays demonstrated that the same supernatants attracted significantly more human peripheral blood mononuclear cells than those of uninfected cells (P<0.001). This model may provide insight into the earliest stages of granuloma formation in those newly infected.

Adult↗

PubMed2006

Immunohistochemical evidence of Clostridium sp, Staphylococcus aureus, and group A Streptococcus in severe soft tissue infections related to injection drug use.

Severe soft tissue infections are caused by either single or multiple microorganisms. We performed a retrospective immunohistochemical (IHC) study on formalin-fixed, paraffin-embedded soft tissue samples from 20 injection drug users who were part of a cluster of severe illness and death after skin and soft tissue infections in Scotland and Ireland in 2000. The IHC assays used antibodies against Clostridium sp, Staphylococcus aureus, group A streptococci, and Bacillus anthracis. Intact bacilli and granular Clostridium antigen staining in areas with necrosis, edema, and inflammation were observed in skin, fascia, or muscle samples of 12 (60%) patients. A variety of clostridia were isolated from affected soft tissues in 10 IHC-positive cases. Staphylococcus aureus antigens were observed in 3 cases including 1 where S aureus was isolated, 1 with negative cultures, and 1 where mixed cultures were obtained. Group A streptococcal antigens were observed in 1 case in which Streptococcus pyogenes and S aureus were isolated. By using IHC, we detected different bacteria in archival soft tissue samples from patients with severe skin and soft tissue infections. Immunohistochemical assays can be of great diagnostic value, particularly for bacteria such as Clostridium sp, which are difficult to isolate because of their anaerobic fastidious growth requirements.

Clostridium Infections↗

PubMed2006

Morphologic, immunologic, and molecular methods to detect bacillus anthracis in formalin-fixed tissues.

Due to the importance of Bacillus anthracis as a cause of naturally occurring infection among humans and as an agent of bioterrorism, there is a vital need for rapid and specific assays, including immunohistochemistry (IHC) and polymerase chain reaction (PCR) assays, to detect the bacterium in formalin-fixed tissues. Colorimetric IHC assays were developed using a multistep indirect immunoalkaline phosphatase method with anti-B. anthracis cell wall (EAII-6G6-2-3) and anti-B. anthracis capsule (FDF-1B9) mAbs to detect B. anthracis antigens in formalin-fixed, paraffin-embedded bacterial cultures and tissues. B. anthracis antigens were localized, using both antibodies, in samples from B. anthracis-infected animals and humans. The colorimetric IHC assay with both antibodies was expedient in diagnosing the presence of B. anthracis in formalin-fixed, paraffin-embedded tissue from bioterrorism-associated cases of inhalational and cutaneous anthrax and from a case of naturally occurring cutaneous anthrax. Using the same antibodies, confocal microscopy demonstrated the structure of replicating B. anthracis in tissues. B. anthracis-specific primers were successfully used with PCR to amplify and detect B. anthracis sequences derived from formalin-fixed tissues of anthrax cases. In this study, morphologic, immunologic, and molecular assays were used to study and diagnose 22 veterinary and human anthrax cases.

Animals↗

PubMed2005

Cell proliferation and inflammation on biopsy samples with multifocal atrophic gastritis before and 1 year after Helicobacter pylori eradication.

CONTEXT: Results of clinical trials that have assessed whether gastric cancer is preventable with Helicobacter pylori eradication therapy remain inconclusive. These trials have used atrophy, intestinal metaplasia, and dysplasia as histopathologic end points that reflect possible preneoplastic lesions. Trial results would be more compelling if cell proliferation and inflammatory markers improved simultaneously with histopathologic lesions. OBJECTIVE: To study the presence of cell proliferation markers and type of inflammatory cells in biopsy specimens with gastritis, atrophy, and intestinal metaplasia before and 1 year after H pylori therapy and to determine if immunohistochemistry can be used to study these. DESIGN: We evaluated 12 subjects with gastritis and 16 with gastritis and multiple foci of atrophy and intestinal metaplasia by using immunohistochemical assays for tumor suppressor protein p53, proliferation marker Ki-67, cell cycle regulator cyclin D1, T and B lymphocytes, macrophages, and TUNEL (terminal deoxynucleotide transferase deoxyuridine triphosphate nick end labeling) assay for apoptosis. The biopsy specimens were selected from a randomized clinical trial that studied improvement of histopathologic gastric lesions after H pylori eradication. RESULTS: Groups of surface epithelial cells that expressed p53 and Ki-67 were observed more often in subjects with atrophy and intestinal metaplasia compared with those with gastritis alone. T lymphocytes in the lamina propria were frequently observed 1 year after treatment in subjects with atrophy and intestinal metaplasia. CONCLUSIONS: Immunohistochemical assays for cell proliferation and inflammatory cell markers showed different distribution patterns in these gastric biopsy specimens. The presence of T lymphocytes and groups of cells that expressed proliferation markers in subjects with multiple foci of atrophy and intestinal metaplasia needs further study.

Apoptosis↗

PubMed2003

Can pre-neoplastic lesions be detected in gastric biopsies of children with Helicobacter pylori infection?

BACKGROUND: Active gastritis, gastric mucosal atrophy and intestinal metaplasia are lesions associated with Helicobacter pylori infection. Atrophy and intestinal metaplasia are only seen in adults. OBJECTIVES: We describe pediatric patients with atrophy and metaplasia, and compare the inflammatory response in these patients to controls. METHODS: As part of a multicenter study of pediatric H. pylori infection, gastric biopsy specimens obtained during diagnostic upper endoscopy of 19 H. pylori-infected children and 45 uninfected controls were reviewed and graded by using the updated Sydney system. The inflammatory response was characterized using immunohistochemistry for T lymphocytes, B lymphocytes, and macrophages, and TUNEL assay for apoptosis. RESULTS: Histology of H. pylori-infected and control biopsy specimens showed active gastritis in 32% and 2% respectively (P = 0.002). Mild intestinal metaplasia was found in 4 H. pylori-infected children, in two of whom it appeared to be accompanied by atrophy. Specimens from patients with H. pylori infection contained increased numbers of B lymphocytes in lymphoid nodules, and apoptosis in the superficial epithelium and inflammatory cells. T lymphocytes and macrophages appeared in similar numbers in specimens from controls and infected patients. CONCLUSIONS: We describe intestinal metaplasia associated with H. pylori infection in children. Since atrophy usually precedes intestinal metaplasia in adults, we suggest that atrophy exists in children. High numbers of B lymphocytes and apoptosis in the surface epithelium are seen in patients with H. pylori infection and may be related to the development of atrophy and intestinal metaplasia.

Adolescent↗

PubMed2003

Chronic myeloid leukemia following therapy with imatinib mesylate (Gleevec). Bone marrow histopathology and correlation with genetic status.

We evaluated bone marrow pathologic features and cytogenetic and molecular genetic status of 13 patients with interferon-resistant, chronic-phase chronic myeloid leukemia (CML), treated with imatinib mesylate (Gleevec). All had morphologic evidence of CML in the blood and bone marrow and were positive for bcr-abl by reverse transcriptase-polymerase chain reaction, fluorescence in situ hybridization (FISH), or both. Follow-up marrow biopsies, interphase FISH for bcr-abl, and conventional cytogenetics were performed at 3-month intervals (up to 24 months) after therapy initiation. All patients exhibited a reduction in bone marrow cellularity with decreases in myeloid/erythroid ratios at 3 to 6 months after therapy. The percentage of bcr-abl-positive cells by FISH decreased in all patients (pretherapy median, 73%; 3 months median, 47%). Cytogenetic and FISH data defined 2 groups after 6 months of follow-up: 5 patients became negative for bcr-abl by FISH; 8 remained positive, 4 of whom developed signs of clonal cytogenetic evolution. Patients who became negative for bcr-abl had no morphologic evidence of CML at 15 to 24 months of follow-up, whereas patients who remained positive redeveloped morphologic features of CML as cellularity increased. Some bcr-abl-positive patients showed signs of progression, including 2 patients who developed myeloid blast phase. Although all patients demonstrated an initial decrease in bone marrow cellularity after imatinib mesylate therapy, continued follow-up showed that histopathologic findings correlated with genetic response.

Antineoplastic Agents↗

PubMed2003

Histopathologic features of Mycobacterium ulcerans infection.

Because of the emergence of Buruli ulcer disease, the World Health Organization launched a Global Buruli Ulcer Initiative in 1998. This indolent skin infection is caused by Mycobacterium ulcerans. During a study of risk factors for the disease in Ghana, adequate excisional skin-biopsy specimens were obtained from 124 clinically suspicious lesions. Buruli ulcer disease was diagnosed in 78 lesions since acid-fast bacilli (AFB) were found by histopathologic examination. Lesions with other diagnoses included filariasis (3 cases), zygomycosis (2 cases), ulcerative squamous cell carcinomas (2 cases), keratin cyst (1 case), and lymph node (1 case). Thirty-seven specimens that did not show AFB were considered suspected Buruli ulcer disease cases. Necrosis of subcutaneous tissues and dermal collagen were found more frequently in AFB-positive specimens compared with specimens from suspected case-patients (p<0.001). Defining histologic criteria for a diagnosis of Buruli ulcer disease is of clinical and public health importance since it would allow earlier treatment, leading to less deforming sequelae.

DNA, Bacterial↗