Streptococcus gallolyticus subspecies pasteurianus (biotype II/2), a newly reported cause of adult meningitis.

We report the first case of adult meningitis confirmed to be due to Streptococcus gallolyticus subsp. pasteurianus. Phenotypically reported as Streptococcus bovis biotype II/2, 16S rRNA sequencing revealed S. gallolyticus subsp. pasteurianus. Because of taxonomic uncertainties, S. gallolyticus subsp. pasteurianus may be an underrecognized agent of systemic infections.

DC-LAMP stains pulmonary adenocarcinoma with bronchiolar Clara cell differentiation.

DC-LAMP is a molecule expressed in mature dendritic cells, but its mRNA is also found in the lung. This study compares the immunostaining spectrum of PE-10, an antisurfactant protein monoclonal antibody; thyroid transcription factor-1 (TTF-1); and DC-LAMP in normal and neoplastic lung in an attempt to characterize the cell type(s) that express DC-LAMP. Electron microscopy was used to define cell types. DC-LAMP marks pulmonary adenocarcinomas that show Clara cell characteristics by electron microscopy. In contrast, PE-10 labels tumors that have Clara cell and type II pneumocyte differentiation. DC-LAMP staining was lost in solid type adenocarcinomas but persisted in well-differentiated areas. CC-10, an antibody that marks Clara cells, was also positive in tumors that labeled for DC-LAMP. There was no prognostic difference in tumors that reacted with DC-LAMP. DC-LAMP and CC-10 reactivity was also observed in endometrial adenocarcinomas but not in other tumor types.

Mitochondrial Iron Accumulation in Parietal and Chief Cells in Iron Pill Gastritis Following Billroth II Gastrectomy: Case Report Including Electron Microscopic Examination.

Iron pill gastritis has been shown to be associated with superficial gastric erosion and deposition of iron in lamina propria and gastric antral glands. However, iron absorption in gastric parietal and chief cells is rare. We present a case of a 62-year-old man with iron deficiency anemia. His past medical history is significant for Billroth II surgery. His medications include ferrous sulphate 325mg. Esophagogastroduodenoscopy showed diffuse circumferential abnormal mucosa at the gastro-jejunal anastomosis. The mucosa was erythematous and violaceous. Biopsy showed reactive gastropathy with iron deposits predominantly in macrophages, parietal cells, and chief cells. These findings were confirmed by iron stain and later by electron micrography of the gastric mucosa that showed iron deposits in mitochondria and cytoplasm of the parietal and chief cells.

A rare case of anal carcinosarcoma with human papilloma virus infection in both biphasic tumor elements: An immunohistochemical, molecular and ultrastructural study.

Carcinosarcoma of the anus is rare and has yet to be reportedly associated with the keratinocyte-specific Human Papilloma Virus (HPV). We describe a case of anal carcinosarcoma with HPV infection in both the epithelial and mesenchymal components of the tumor by immunohistochemistry, chromogenic in-situ hybridization (CISH) and further supported by electron microscopy (EM). Microscopic examination of the tumor showed nests of poorly-differentiated invasive squamous cell carcinoma with basaloid features intermixed with a hypercellular, atypical spindle cell proliferation. Immunohistochemistry demonstrated that the epithelial component was positive for AE1/AE3, p63, CK5/6 and p16, whilst the mesenchymal component was positive for smooth muscle actin, vimentin, and focally positive for desmin and p16, consistent with carcinosarcoma. The tumor was negative for GATA-3, CK7 and CK20. CISH demonstrated that the tumor was positive for high risk HPV (subtype 16/18) in both tumor components. EM further supported the presence of intracellular virus particles (~50 nm) that is compatible with HPV infection. Infection of both epithelial and mesenchymal tumor components by HPV has not been previously observed in the gastrointestinal tract. This finding may represent initial epithelial HPV infection with subsequent divergent tumoral differentiation and suggests the presence of viral replication in both biphasic tumor components.

Preferential induction of necrosis in human breast cancer cells by a p53 peptide derived from the MDM2 binding site.

p53 is the most frequently altered gene in human cancer and therefore represents an ideal target for cancer therapy. Several amino terminal p53-derived synthetic peptides were tested for their antiproliferative effects on breast cancer cell lines MDA-MB-468 (mutant p53), MCF-7 (overexpressed wild-type p53), and MDA-MB-157 (null p53). p53(15)Ant peptide representing the majority of the mouse double minute clone 2 binding site on p53 (amino acids 12-26) fused to the Drosophila carrier protein Antennapedia was the most effective. p53(15)Ant peptide induced rapid, nonapoptotic cell death resembling necrosis in all breast cancer cells; however, minimal cytotoxicity was observed in the nonmalignant breast epithelial cells MCF-10-2A and MCF-10F. Bioinformatic/biophysical analysis utilizing hydrophobic moment and secondary structure predictions as well as circular dichroism spectroscopy revealed an alpha-helical hydrophobic peptide structure with membrane disruptive potential. Based on these findings, p53(15)Ant peptide may be a novel peptide cancer therapeutic because it induces necrotic cell death and not apoptosis, which is uncommon in traditional cancer therapy.

Fine-needle aspiration cytology of pancreatoblastoma in a young woman: report of a case and review of the literature.

Pancreatoblastoma is a rare tumor and has been reported only four times in the cytologic literature, three times in fine-needle aspiration (FNA) biopsy and once in an imprint of resected tumor. We are reporting the fourth case of FNA cytology with immunohistochemical and electron microscopic studies. The patient is a 24-yr-old African American woman, who presented with a pancreatic mass, hepatic masses, and abdominal lymphadenopathy. The aspiration smears of the liver mass showed a biphasic tumor composed of bland-appearing primitive spindled stromal fragments with "spider-web"-like long fibrils interconnecting with sharply angulated islands of cohesive epithelium. At high power, the epithelium is composed of medium-sized cells with round-to-oval vesicular nuclei with fine chromatin and one-to-two small nucleoli. The neuroendocrine component was demonstrated immunohistochemically with synaptophysin and chromogranin expressions. The acinar component and squamoid component were demonstrated ultrastructurally by the presence of 400-600 nm zymogen granules and tonofilaments. The literature was reviewed and the cytological features of all the four cases of pancreatoblastoma are summarized.

AA-type amyloidosis associated with non-Hodgkin's lymphoma: a case report.

Amyloid-associated protein (AA)-type systemic amyloidosis has been referred to as secondary amyloidosis because it is secondary to an associated inflammatory condition. It is extremely rare in patients with non-Hodgkin's lymphoma (NHL). Here we report an autopsy case of follicular small cleaved cell lymphoma with focal large B-cell lymphoma transformation in association with systemic AA-type amyloidosis. Formalin-fixed, paraffin-embedded tissues from autopsy and the patient's previous surgical specimen were studied by Congo red stain; electron microscopy; and immunostaining with antibodies against AA protein, P component, and kappa and lambda light chains. There was a marked AA amyloid deposition in the glomeruli of both kidneys, the retroperitoneal lymphoma mass, the blood vessels, the adrenal glands, and the adipose tissues. The patient's previous surgical specimens were negative for amyloid. We propose that this patient's systemic AA-type amyloidosis developed along the course of his NHL.

The concept of bronchioloalveolar cell adenocarcinoma: redefinition, a critique of the 1999 WHO classification, and an ultrastructural analysis of 155 cases.

Bronchioloalveolar cell adenocarcinoma (BACA) is bronchioloalveolar because (1) it arises in bronchioles and alveoli and (2) differentiates into bronchiolar and alveolar cells. Every entity possesses unique characteristics that separate it from other entities. The unique characteristic of BACA is its cell type. Lepidic growth is a clue to the cell type and, even though present in the vast majority, is not unique or absolutely essential. Because of the algebraic nature of concepts, the degree of differentiation, the extent of lepidic growth, and the degree of stromal desmoplasia cannot be used as definitional requirements. Likewise, in malignant tumors, absence of stromal invasion cannot be required. An epistemologically valid definition of BACA is proposed and a study of 155 cases defined this way and examined ultrastructurally is presented.

Bilateral tubulocystic renal cell carcinomas in diabetic end-stage renal disease: first case report with cytogenetic and ultrastructural studies.

Tubulocystic renal cell carcinoma (TC-RCC) is a rare renal tumor composed of well-differentiated tubules and cysts lined by neoplastic cells with eosinophilic cytoplasm and prominent nucleoli. The origin of the tumor cells is still controversial. TC-RCC typically arises unilaterally. Involvement of both kidneys by multifocal TC-RCC has not been reported. In this study we report the first case of bilateral and multifocal TC-RCC. Immunohistochemical, cytogenetic and ultrastructural studies suggest TC-RCC is closely related to papillary RCC.

Redirecting apoptosis to aponecrosis induces selective cytotoxicity to pancreatic cancer cells through increased ROS, decline in ATP levels, and VDAC.

Pancreatic cancer cell lines with mutated ras underwent an alternative form of cell death (aponecrosis) when treated concomitantly with clinically achievable concentrations of arsenic trioxide, ascorbic acid, and disulfiram (Antabuse; AAA). AAA's major effects are mediated through generation of intracellular reactive oxygen species (ROS) and more than 50% decline in intracellular ATP. N-acetyl cysteine and a superoxide dismutase mimetic prevented aponecrosis and restored intracellular ATP levels. DIDS (4,4'-diisothiocyanatostilbene-2, 2' disulfonic acid), the pan- Voltage-Dependent Anion Channel (VDAC), -1, 2, 3 inhibitor and short hairpin RNA (shRNA) to VDAC-1 blocked cell death and ROS accumulation. In vivo exposure of AAA led to a 62% reduction in mean tumor size and eliminated tumors in 30% of nude mice with PANC-1 xenografts. We concluded that early caspase-independent apoptosis was shifted to VDAC-mediated "targeted" aponecrosis by the addition of disulfiram to arsenic trioxide and ascorbic acid. Conceptually, this work represents a paradigm shift where switching from apoptosis to aponecrosis death pathways, also known as targeted aponecrosis, could be utilized to selectively kill pancreatic cancer cells resistant to apoptosis.

Extranodal Rosai-Dorfman disease arising in the right atrium: a case report with literature review.

Rosai-Dorfman disease is a rare, benign histiocytic proliferative disorder that commonly affects the lymph nodes. Although extranodal involvement has been reported in diverse sites, manifestation in the cardiovascular system is extremely uncommon. Specifically, the involvement of the heart by Rosai-Dorfman disease is an extraordinarily infrequent event. Here, the authors present a case of Rosai-Dorfman disease arising in the right atrium in a symptomatic 61-year-old man who initially presented with pleuritic chest pain and was found to have a large, lobulated, and circumscribed right atrial mass. The lesion exhibited an exuberant histiocytic and chronic fibroinflammatory process with focal emperipolesis within histiocytes. Immunohistochemical studies demonstrated strong S100 positivity in CD68+ CD1a- histiocytes. Although rare, Rosai-Dorfman disease should be considered in the differential diagnosis of a right atrial mass.

Case report: Paenibacillus thiaminolyticus: a new cause of human infection, inducing bacteremia in a patient on hemodialysis.

Paenibacilli are gram-positive, aerobic bacteria that are related to Bacilli but differ in the DNA encoding their 16S rRNA. Until recently, these organisms were not known to cause human disease. There are now several reports of human infection caused by a few members of this genus, most commonly by P. alvei. We report a human infection in a patient with a permacath for chronic hemodialysis who was found to have bacteremia caused by P. thiaminolyticus, which is an environmental bacterium that has never been found to cause human disease. We identified this bacterium by biochemical tests, cloning, sequencing the genomic DNA encoding its 16S rRNA, growth characteristics, and electron microscopic studies. This constitutes the first report of a human infection caused by this organism.

Activation of targeted necrosis by a p53 peptide: a novel death pathway that circumvents apoptotic resistance.

Cancer cells escape apoptosis by intrinsic or acquired mechanisms of drug resistance. An alternative strategy to circumvent resistance to apoptosis could be through redirection into other death pathways, such as necrosis. However, necrosis is a nonspecific, nontargeted process resulting in cell lysis and inflammation of both cancer and normal cells and is therefore not a viable alternative. Here, we report that a C-terminal peptide of p53, called p53p-Ant, induced targeted necrosis only in multiple mutant p53 human prostate cancer lines and not normal cells, because the mechanism of cytotoxicity by p53p-Ant is dependent on the presence of high levels of mutant p53. Topotecan- and paclitaxel-resistant prostate cancer lines were as sensitive to p53p-Ant-induced targeted necrosis as parental lines. A massive loss of ATP pools and intracellular generation of reactive oxygen species was involved in the mechanism of targeted necrosis, which was inhibited by O(2)(.) scavengers. We hypothesize that targeted necrosis by p53p-Ant is dependent on mutant p53, is mediated by O(2)(.) loss and ATP, and can circumvent chemotherapy resistance to apoptosis. Targeted necrosis, as an alternative pathway for selective killing of cancer cells, may overcome the problems of nonspecificity in utilizing the necrotic pathway.

Subcellular localization of phosphatidylinositol synthesis.

It is well-established that the endoplasmic reticulum is the major site of phosphatidylinositol (PtdIns) synthesis. The PtdIns synthetic ability of other organelles, such as plasma membrane and nucleus, remains controversial. In the present study, we re-examine this question by comparing PtdIns synthesis in isolated cytoplasts (enucleated cells) with that in corresponding karyoplasts (nuclei surrounded by plasma membrane but lacking most cytoplasmic components). We report that cytoplasts are competent to carry out both basal and stimulated PtdIns synthesis as well as polyphosphoinositide hydrolysis, while karyoplasts can neither synthesize PtdIns nor hydrolyze phosphoinositides in response to agonists. The karyoplasts are, however, capable of synthesizing phosphatidylcholine (PtdCho), as previously reported. From these data, we conclude that PtdIns synthesis is limited to cytoplasmic components, and cannot be sustained by either plasma membrane or nucleus under conditions that permit robust PtdCho synthesis.

Merkel cells, normal and neoplastic: an update.

Merkel cells (MC) occur in the basal epidermal layer, hair follicles, and oral mucosa, as complexes with sensory axons. The axons transduce slowly adapting type I mechanoreception, and MC modulate their sensitivity. MC also determine and maintain the 3-dimensional epidermal structure. They have neuroendocrine granules, rigid spinous processes, and desmosomal junctions with each other and with keratinocytes. Rare MC are dermaWl. Current evidence supports a basal cell origin. Merkel cell carcinomas (MCC) occur mostly in sun-exposed skin in old age. Trabecular, intermediate, or small cell in pattern, MCC have neuroendocrine granules, intercellular junctions, rigid spinous processes, and a paranuclear collection of intermediate filaments staining for cytokeratin 20. Most MCC behave indolently, but those with the small cell pattern, and some with the intermediate pattern, are aggressive and rapidly fatal.

Pneumocystis carinii: an update.

Pneumocystis produces respiratory infection in immunocompromised individuals of several species of mammals, including humans. Each mammalian species has its own specific Pneumocystis species, which does not cross-infect other mammals. The species infecting humans has now been renamed P. jerovici, since P. carinii is reserved for one of two species infecting rats. Long believed to be a protozoan, Pneumocystis is now classified as an Archiascomycetous fungus. This is based on new molecular taxonomic techniques using DNA sequence analysis of srRNA genes. Only two of about 140 copies of the gene that exist in Pneumocystis were used for sequencing, so the evidence is not conclusive; however, it is supported by morphological evidence such as fungus-specific nucleus-associated organelles for cell division. There is also ultrastructural evidence of meiotic division and sexual conjugation. Clinically, several lines of evidence suggest the improbability of latent infection. Adult infections appear to be new infections, a fact that invites a new perspective on prevention.

Ultrastructurally "invasive" microvilli in an aggressively metastasizing biphasic malignant mesothelioma.

The presence of long, slender, often branching microvilli on cell surfaces is a characteristic feature of malignant and benign mesothelial cells. However, these typical microvilli are seen only in better-differentiated lumens within epithelial areas of malignant mesotheliomas. Presented here are the clinical and ultrastructural findings in a biphasic malignant mesothelioma that lacked lumens, but possessed very long microvilli. These invaginated deeply into the cytoplasm of neighboring tumor cells, as well as into the surrounding stromal matrix. The tumor cells had well-formed intercellular desmosomal junctions. The primary tumor was localized to the pleura and invaded the chest wall, but only minimally the lung. Lobectomy demonstrated the presence of metastatic tumor in 2 peribronchial lymph nodes. The disease progressed rapidly and, within 6 months, killed the patient. An autopsy revealed widespread metastases in multiple systemic organs. The authors speculate that the unique ultrastructural features of this case may be a clue to the unusually aggressive course of the neoplasm.

Parietal cell carcinoma of gastric cardia: immunophenotype and ultrastructure.

The case is reported of a clinically aggressive parietal cell carcinoma of the gastric cardia in a 67-year-old man. Histologically, the tumor was a poorly differentiated adenocarcinoma with a predominantly solid growth pattern, though with areas exhibiting glandular morphology and with extensive lymphatic invasion. The tumor cells had eosinophilic, finely granular cytoplasm, with focal Alcian blue-positive mucin in the gland lumens. Ultrastructural examination of the pleural metastasis and gastrectomy specimen demonstrated many mitochondria, tubulovesicular profiles of endoplasmic reticulum, and intracytoplasmic lumens, which resembled intracellular canaliculi of parietal cells. Immunohistochemically, there was positive staining of tumor cells for the parietal cell specific antibodies to H/K-ATPase and human milk fat globule-2 (HMFG-2).

Detection of extracellular forms of babesia in the blood by electron microscopy: a diagnostic method for differentiation from Plasmodium falciparum.

Light microscopic examination of blood smears is the traditional approach for the diagnosis of babesiosis, but there is morphological overlap with Plasmodium falciparum. The authors describe 3 patients with babesial infection in whom the diagnosis was made by identifying extracellular merozoites in a buffy coat preparation using electron microscopy. This method resulted in a high yield of extracellular babesia, even in a case where virtually no extracellular babesia were detectable in the blood smear. The test had a reasonably fast turnaround time and allowed detailed visualization of the organisms and reliable distinction from Plasmodium falciparum.