Biomedical subjects

M Tsokos

Publications and source records attributed to M Tsokos.

At least 73 records · Page 4Linked to original sources

PubMed1999

Skin and soft tissue artifacts due to postmortem damage caused by rodents.

Five cases of postmortem bite-injuries inflicted by rodents are presented (five males between 41 and 89 years; three cases caused by mice, one case by rats, one case of possible mixed rodent activity by rats and mice). The study presents a spectrum of phenomenological aspects of postmortem artifacts due to rodent activity to fresh skin and soft tissue: the majority of the injuries have a circular appearance. The wound margins are finely serrated with irregular edges and circumscribed 1-2 mm intervals within, partly showing protruding indentations up to 5 mm. Distinct parallel cutaneous lacerations deriving from the biting action of the upper and lower pairs of the rodents incisors are diagnostic for tooth marks of rodent origin but cannot always be found. No claw-induced damage can be found in the skin beyond the wound margins. Areas involved in the present study were: exposed and unprotected parts of the body, such as eyelids, nose and mouth (representing moist parts of the face); and the back of the hands. Postmortem rodent activity may occasionally be expected on clothed and therefore protected parts of the body. The phenomenon of postmortem rodent activity to human bodies can be found indoors especially under circumstances of low socioeconomic settings; outdoors this finding is particularly observed among fatalities among homeless people.

Adult↗

PubMed1999

Calcium ionophore-treated myeloid cells acquire many dendritic cell characteristics independent of prior differentiation state, transformation status, or sensitivity to biologic agents.

We previously reported that treatment of human peripheral blood monocytes or dendritic cells (DC) with calcium ionophore (CI) led to the rapid (18 hour) acquisition of many characteristics of mature DC, including CD83 expression. We therefore investigated whether less-mature myeloid cells were similarly susceptible to rapid CI activation. Although the promyelocytic leukemia line HL-60 was refractory to cytokine differentiation, CI treatment induced near-uniform overnight expression of CD83, CD80 (B7.1), and CD86 (B7. 2), as well as additional characteristics of mature DC. Several cytokines that alone had restricted impact on HL-60 could enhance CI-induced differentiation and resultant T-cell sensitizing capacity. In parallel studies, CD34(pos) cells cultured from normal donor bone marrow developed marked DC-like morphology after overnight treatment with either rhCD40L or CI, but only CI simultaneously induced upregulation of CD83, CD80, and CD86. This contrasted to peripheral blood monocytes, in which such upregulation could be induced with either CI or rhCD40L treatment. We conclude that normal and transformed myeloid cells at many stages of ontogeny possess the capacity to rapidly acquire many properties of mature DC in response to CI treatment. This apparent ability to respond to calcium mobilization, even when putative signal-transducing agents are inoperative, suggests strategies for implementing host antileukemic immune responses.

Antigens, CD↗

PubMed1999

Hemihypertrophy and a poorly differentiated embryonal rhabdomyosarcoma of the pelvis.

BACKGROUND: Asymmetry of the limbs (conventionally known as hemihypertrophy) is one of the overgrowth syndromes occurring sporadically in the general population at a frequency of approximately 1:86,000. Hemihypertrophy is also reported as part of the Beckwith-Wiedemann syndrome which has as its cardinal features omphalocele, macroglossia and gigantism with hypoglycemia, organomegaly, renal anomalies, hemihypertrophy, and embryonal tumors occurring less frequently. Various neoplasms are also associated with isolated hemihypertrophy. Wilms tumor, adrenocortical carcinoma, and hepatoblastoma are the most frequent. Rhabdomyosarcoma, neuroblastoma, phaeochromocytoma, and undifferentiated sarcoma of the lung are encountered only rarely. Loss of heterozygosity (LOH) of chromosome 11p15.5 is strongly associated with childhood embryonal tumors, particularly Wilms tumor, hepatoblastoma, and rhabdomyosarcoma. PROCEDURE AND RESULTS: In this article, we describe an adolescent male with congenital asymmetry of the lower limbs who presented with a large poorly differentiated pelvic sarcoma. Conventional histologic, immunohistochemical, and ultrastructural studies of this tumor were insufficient for accurate subclassfication. However, positive staining for MyoD1 (a recently identified embryonically expressed marker of muscle differentiation) and LOH at the tyrosine hydroxylase locus of chromosome 11p15.5 by molecular analysis favored the diagnosis of embryonal rhabdomyosarcoma over an undifferentiated sarcoma. CONCLUSIONS: This case stresses the importance of pursuing clinical findings when they occur in conditions with an increased risk of developing cancer, which in this case was asymmetry of a limb. Also illustrated by this patient is the need for early consideration of molecular diagnostic tests where available, to refine an uncertain pathologic diagnosis that may ultimately have an impact on treatment and prognosis.

Adolescent↗

PubMed1999

Macromorphology and histology of intramuscular hemorrhages in cases of drowning.

In a prospective autopsy series of 39 cases of fatal drowning, the detailed dissection of the skeletal muscles of the neck, anterior/posterior trunk and the upper extremities in layers revealed intramuscular hemorrhages of different size and shape in 20 cases (51.3%). Light microscopy examination showed a premortal (vital/agonal) type of muscular alteration in 7 (50%) out of 14 macroscopical hemorrhage-positive cases. These hemorrhages and histological muscle alterations are attributed to agonal convulsions, hypercontraction and overexertion of the affected muscle groups. As long as no cutaneous or subcutaneous hematomas above the hemorrhages can be found, these autopsy findings (with special reference to histology) can serve as an additional criterion concerning the differentiation of drowning and another cause of death.

Adolescent↗

PubMed1999

Indoor postmortem animal interference by carnivores and rodents: report of two cases and review of the literature.

We present two cases of nearly total skeletization of the exposed face and neck due to indoor postmortem animal interference and a review of the literature. In the case of a 61-year-old man, inspection of the damaged soft tissue margins revealed serrated edges and parallel cutaneous lacerations caused by rats. In the case of a 40-year-old woman, postmortem examination revealed v-shaped and rhomboid-shaped tunneled wounds in the damaged soft tissue caused by a pit bull terrier. The autopsy in both cases identified natural causes of death. While the morphological feature of postmortem soft tissue artifacts caused by rodents can be ascribed to animal incisors, stab wound-like punctured wounds are characteristic of canine dentition of carnivorous origin. Additional morphological criteria for injuries of carnivorous origin are linear scratch-type abrasions from claws in the vicinity of the injuries. In cases of indoor postmortem animal interference damage is primarily caused to the exposed areas of the body, no self-defense injuries can be found on the deceased's body, only a small amount of blood or the total absence of bloodstains should be expected at the scene, an inquiry of pets living free in the house or wild animals having possible access to the scene should be conducted and rodent excrement found at the scene can give the investigator further information.

Adult↗

PubMed1999

Iatrogenic staphylococcus aureus septicaemia following intravenous and intramuscular injections: clinical course and pathomorphological findings.

The clinical course, autopsy and histological findings are presented from three (one 33-year-old female and two males aged 26 and 56) fatalities resulting from injection therapy which has produced Staphylococcus aureus septicaemia. The autopsies were performed within 2-4 days postmortem. No primary focus other than the insertion site of the peripheral venous catheters or the intramuscular injections, representing the initial entry site of Staphylococcus aureus, could be identified. Death was attributed directly to the staphylococcal infection as a result of iatrogenic injection therapy for the treatment of a non-severe underlying illness (premature labour pains, acute loss of hearing, lumbago). The forensic diagnosis of Staphylococcus aureus septicaemia following iatrogenic injections has to be critically evaluated and can be established routinely in cases with delayed autopsy only when no other cause of death is revealed by autopsy, no apparent source of infection other than the insertion site can be detected and careful attention is paid to histological and bacteriological findings. All doubtful cases of nosocomial bloodstream infections with fatal outcome should undergo an immediate autopsy. In cases of very early forensic involvement microbiological investigations, including phagotyping, molecular biological characterization and identification of bacterial toxins from micro-organisms out of appropriate specimens obtained postmortem, could be efforts of potential evidential value regarding the aetiological proof. To optimize aetiopathogenetic conclusions concerning a causal relationship between iatrogenic injections and septic complications, the medicolegal investigation should also include an interdisciplinary co-operation with consultants from other relevant fields (e.g. microbiology and hygienics).

Adult↗

PubMed1999

Perimortem fixation of the gastric and duodenal mucosa: a diagnostic indication for oral poisoning.

Two cases of fatal oral poisoning are presented. In the first case, a 40-year-old man died due to a lethal dose of mercury (blood concentration 113.8 microg/ml) and in the second, a 34-year-old man died of chloralhydrate overdose with a lethal blood concentration of trichloroethanol (52 microg/ml), the active metabolite of chloralhydrate. In both cases gross examination and histology showed an unusually well preserved gastrointestinal mucosa in addition to unspecific signs of intoxication. The two cases demonstrate that the phenomenon of perimortal fixation is a useful indication for the forensic pathologist and should direct the suspicion to oral poisoning. The detection of fixation facilitates toxicology screening by indicating that the relevant substance must have the capability to precipitate proteins.

Adult↗

PubMed1999

Non-traumatic liver rupture due to a perforated gastric ulcer.

The case of a 57-year-old woman with a fatal liver rupture due to a necrotizing perihepatic abscess caused by a perforated gastric ulcer is presented. The ulcer had been treated successfully by surgical intervention 8 days before. The autopsy revealed a large perihepatic abscess and multiple ruptures of Glisson's capsule with a large subcapsular hematoma and underlying lacerations of the liver parenchyma. The patient had no history of previous abdominal trauma and the known etiological factors for spontaneous liver rupture were excluded by the autopsy findings or by clinical and laboratory data. No liver penetration by the gastric ulcer was found at autopsy and there were no clinical signs or symptoms for an infection or any degenerative or inflammatory diseases. Histologically abundant vegetable fibers, identified as stomach contents and a dense infiltrate of lymphocytes and granulocytes were found in the perihepatic abscess next to Glisson's capsule. Below Glisson's capsule there were hemorrhages, focal hepatocellular necrosis and a mixed cell inflammatory infiltration. In the present case, preceding perforation of the gastric ulcer with leaking of gastric acid into the peritoneal cavity resulted in peptic digestion of Glisson's capsule. Vascular lesions of the affected parts of Glisson's capsule and the liver parenchyma underneath resulted in intrahepatic hemorrhage and an increase in intrahepatic pressure with subsequent liver rupture. To the authors' knowledge no similar case of spontaneous liver rupture due to perforation of a gastric ulcer has been reported previously.

Cause of Death↗

PubMed1999

Detection of EWS-FLI-1 fusion in Ewing's sarcoma/peripheral primitive neuroectodermal tumor by fluorescence in situ hybridization using formalin-fixed paraffin-embedded tissue.

The balanced translocation t(11;22)(q24;q12) is specific for the Ewing's sarcoma/peripheral primitive neuroectodermal tumors (ES/PNETs) and results in the EWS/FLI-1 fusion transcript, which can be detected by reverse transcription polymerase chain reaction (RT-PCR). Recent studies also have used fluorescence in situ hybridization (FISH) to show the translocation; however, most of these have been performed on cell lines or touch preparations and short-term cultures of tumors. Moreover, the existing probes generally have shown only the break in the specific chromosomes rather than the translocation itself. We describe our findings with a new set of probes that localize to 22q12 (EWS) and 11q24 (FLI-1) and directly show the translocation as juxtaposed red-green signals on der(22) in nuclei extracted from formalin-fixed, paraffm-embedded tissues. After establishing the specificity of the probes (on metaphase spreads and interphase nuclei in two translocation-positive cell lines and normal peripheral blood lymphocytes), we evaluated 11 ES/PNETs and 10 other tumors (four alveolar rhabdomyosarcomas, three neuroblastomas, two lymphomas, one extramedullary myeloid tumor) using a two-color FISH assay. All 11 ES/PNETs showed fusion signals in 20% to 80% of evaluable nuclei. In two lymphoma cases, random overlapping signals were present in 2% and 4% of nuclei, whereas the remaining eight tumors were negative. The presence of t(11;22) was confirmed by RT-PCR in 10 of 11 ES/PNETs. We conclude that FISH analysis with this newly designed probe pair is a specific and sensitive method of detecting t(11;22) on routinely processed tissue and can be useful in the differential diagnosis of ES/PNETs from other small round blue cell tumors when only fixed tissue is available.

Adolescent↗

PubMed1999

Absence of EWS/FLI1 fusion in olfactory neuroblastomas indicates these tumors do not belong to the Ewing's sarcoma family.

The balanced reciprocal translocation t(11;22)(q24;q12) is a specific molecular marker for the Ewing's sarcoma family of tumors (ESFT). Based on the detection of this translocation in some olfactory neuroblastomas (ONBs), it has been proposed that ONBs also belong to the ESFT. Others have challenged this hypothesis; however, the rarity of ONBs, as well as the lack of molecular techniques that work reliably on formalin fixed tissue, have precluded the molecular analysis of a significant number of cases. We evaluated the immunophenotypic and molecular features of 17 paranasal small round neuroectodermal tumors using routinely fixed tissue. Probes localizing to 22q12 (EWS) and 11q24 (FLI-1) were used in a standard 2-color fluorescence in situ hybridization (FISH) assay to evaluate EWS/FLI1 fusion on the der(22). Sixteen tumors were mic-2 negative, whereas 1 tumor was mic-2 positive, compatible with ONB and ESFT, respectively. Thirteen of 15 ONBs could be evaluated by FISH, and all 13 were negative for the EWS/FLI1 fusion. Distinct fusion signals were identified in the single paranasal ESFT. Our findings indicate that ONBs lack the EWS/FLI1 fusion and are unrelated to the ESFT; however, true ESFTs may rarely occur as primary sinonasal tumors.

Adolescent↗

PubMed1999

Neuroectodermal differentiation in Ewing's sarcoma family of tumors does not predict tumor behavior.

The observation that neuroectodermal differentiation imparts a worse prognosis to the Ewing family of tumors has been suggested by some studies and refuted by others. To assess whether the diagnosis of Ewing's sarcoma versus peripheral primitive neuroectodermal tumor (PNET) affects prognosis, we analyzed tumors from 63 analogously treated pediatric and young adult patients from the National Cancer Institute and St Jude Children's Research Hospital and retrospectively compared the results with clinical outcomes. The tumors were assessed using standard light microscopy and immunohistochemical stains for neuron-specific enolase, CD57, S100 protein, neurofilament protein, and synaptophysin with or without antigen retrieval. Ultrastructural evaluation was also performed in 39 tumors. Classification was performed using Kiel criteria as well as a modified classification. Kaplan-Meier analyses, with Mantel-Haenzel evaluation of the significance of the differences, were performed separately for localized or metastatic tumors. Using the Kiel classification on a subset of 60 cases, 39 tumors qualified as PNET and 21 as Ewing's sarcoma. Using the modified classification on a subset of 61 cases, 14 were classified as PNET, 21 as atypical Ewing's sarcoma, and 26 as Ewing's sarcoma. The addition of electron microscopy to the diagnostic armamentarium significantly increased the likelihood of identifying PNET. No significant differences in event-free or overall survival were seen using either the modified or Kiel classification, regardless of the ancillary diagnostic techniques employed. In this exploratory analysis, neuroectodermal differentiation did not play a role in clinical outcome. Confirmation of this finding will require a larger, separate study of similarly treated patients, and it may not apply to older patients.

Adolescent↗

PubMed1999

Sensitive detection of rare Ewing's sarcoma cells in peripheral blood by reverse transcriptase polymerase chain reaction.

Disseminated disease is very important in the clinical assessment of pediatric sarcomas. Several reports suggest that reverse transcriptase polymerase chain reaction (RT-PCR) holds great promise in the early staging of cancer patients in general. However, the complexities of these protocols hamper adequate standardization, and their application as routine diagnostic tools has been difficult. The aim of this study is to assess the actual minimal number of tumor cells that may be detected by RT-PCR in a blood sample. Specific tumor cell dilutions from a Ewing's sarcoma cell line reconstituted in peripheral blood from healthy individuals were "ficolled" and submitted to RNA extraction for cDNA preparation and PCR amplification of the t(11-22) (q24;q12) fusion transcript. After PCR amplification, we were able to detect the EWS/FI-1 chimeric gene product at a dilution of 10 tumor cells per 1 or 2 mL of blood. Our simple method supports a role for routine clinical use of RT-PCR in the detection of circulating Ewing's sarcoma cells.

Artificial Gene Fusion↗

PubMed1999

Unusual injury pattern in a case of postmortem animal depredation by a domestic German shepherd.

A case is presented of a 38-year-old woman with skeletization of the head, neck, and collar region and a circumscribed 26-cm x 19-cm defect on the left chest with sole removal of the heart through the opened pericardium but undamaged mediastinum and lungs. The injuries showed V-shaped puncture wounds and superficial claw-induced scratches adjacent to the wound margins that have been described as typical for postmortem animal depredation of carnivore origin and derived from postmortem animal damage by the woman's domestic German shepherd. The circumscribed destruction of the left chest with unusual opening of the pericardium is explained by the physiognomy of the muzzle of the German shepherd and differs from previous reports. Any case presented as postmortem animal mutilation should be viewed with skepticism and undergo a full autopsy.

Adult↗

PubMed1999

Lysosomal inclusions in gastric parietal cells in mucolipidosis type IV: a novel cause of achlorhydria and hypergastrinemia.

Mucolipidosis type IV (ML-IV) is an autosomal recessive lysosomal storage disease that causes severe neurologic abnormalities. The brain disease is characterized by pigmented cytoplasmic granules in neurons and accumulation of lamellated membrane structures in lysosomes. The gastrointestinal disease in ML-IV was not previously recognized. Clinical examination of 20 patients with ML-IV (age range, 2-23 years) at the National Institutes of Health showed hypergastrinemia and constitutive achlorhydria. Endoscopic biopsy specimens from the gastric fundus, body, and antrum and from the duodenum of four such patients (ages 4, 6, 7, and 22 years) were evaluated histologically and by electron microscopy. Histologically, all gastric fundus and body biopsy specimens showed parietal cells in normal numbers. However, a striking cytoplasmic vacuolization of parietal cells was seen on hematoxylin and eosin stain. Electron microscopy showed the parietal cells to be markedly distended by large lysosomes containing lamellar, concentric, and cystic membranous inclusions. Additionally, chronic atrophic gastritis and enterochromaffin-like (ECL) cell hyperplasia were observed. Foveolar and chief cells in stomach and duodenum biopsy specimens were normal. We conclude that the cytoplasmic lysosomal inclusions in gastric parietal cells is a unique histologic feature of gastric biopsy in ML-IV.

Achlorhydria↗

PubMed1999

Myc oncogene expression and nude mouse tumorigenicity and metastasis formation are higher in alveolar than embryonal rhabdomyosarcoma cell lines.

Accumulated clinical evidence suggests that alveolar rhabdomyosarcoma (ARMS) is more aggressive than embryonal rhabdomyosarcoma (ERMS). Here, we study six childhood rhabdomyosarcoma cell lines, three ERMS and three ARMS. We have assayed the ability of the tumor cells to grow in culture and in nude mice as well as their propensity for pulmonary metastasis formation by tail vein injection. We also compared levels of c- and N-myc oncogene expression and DNA copy number. We find no correlation of histologic tumor type (i.e. ERMS versus ARMS) with growth rate in culture, but we do find suggestive correlations of histologic type with tumorigenicity (mean tumor diameter in millimeters at 6 wk: ARMS 30, ERMS 10; p1 = 0.1) and metastasis formation (ARMS 12, ERMS 0; p1 = 0.1). These properties also correlate with uniform greater overexpression of c-myc in ARMS (mean 39.3-fold, range 16-83) compared with ERMS (mean 5.3, range 4-8) (p1 = 0.05, control fibroblasts = 1). Although c-myc was often amplified in vitro (four of six lines), there was no correlation with histologic type (2/3 ARMS, 2/3 ERMS). These data on rhabdomyosarcoma cell lines derived from verified ERMS and ARMS tumors support the impression from previous clinicopathologic observations that ARMS is a more malignant form of rhabdomyosarcoma than ERMS.

Animals↗

PubMed1999

Fas ligand expression in thyroid carcinomas: a potential mechanism of immune evasion.

Fas ligand (FasL) induces apoptosis by cross-linking the Fas receptor and is expressed by cells of the immune system. Recently, FasL was found in malignant tumors, suggesting that it helps them escape immune surveillance by eliminating infiltrating lymphocytes. We investigated the presence of FasL immunohistochemically in 48 thyroid carcinomas and by Western blotting and RT-PCR in 5 thyroid carcinoma cell lines. We found that in contrast to normal thyroid tissue, FasL was highly expressed in all papillary, follicular, and Huerthle carcinomas. Medullary carcinomas lacked or had minimal FasL expression. In papillary carcinomas, high levels of expression correlated independently with aggressive histology and unfavorable clinical presentation. FasL was also present in all thyroid cell lines. Thyroid carcinoma cells killed Fas-sensitive targets in a FasL-dependent manner in a coculture experiment. Cross-linking of Fas induced apoptosis in thyroid carcinoma cells only in the presence of cycloheximide. We conclude that FasL is specifically expressed in thyroid carcinomas of follicular epithelial origin, may help them evade the immune system, and may have prognostic implications in papillary carcinoma, as it is associated with a more aggressive phenotype. Thyroid carcinoma cells avoid Fas-mediated suicide possibly by expressing an inhibitor of the Fas apoptotic pathway.

Adolescent↗

PubMed1999

Phenylbutyrate induces cell differentiation and modulates Epstein-Barr virus gene expression in Burkitt's lymphoma cells.

Although Burkitt's lymphoma (BL) is a readily treated malignancy, recurrences, as well as disease arising in immunosuppressed patients, are notoriously resistant to conventional therapeutic approaches. The EBV is associated with a significant proportion of these lymphomas that evade immune surveillance through decreased expression of both viral and cellular antigens. Increasing the immunogenicity of BL cells may, therefore, represent a potentially beneficial therapeutic maneuver. Using in vitro models of EBV-transformed lymphoblastoid as well as BL cell lines, we demonstrate increased expression of genes coding for HLA class I and EBV latent proteins by the differentiation inducer phenylbutyrate (PB). The aromatic fatty acid also caused cytostasis associated with sustained declines in c-myc expression, a direct antitumor effect that was independent of the EBV status. We conclude, therefore, that differentiation therapy of BL with PB may lead to growth arrest with increased tumor immunogenicity in vivo. The findings may have clinical relevance because the in vitro activity has been observed with PB concentrations that are well tolerated and nonimmunosuppressive in humans, a desirable feature for the different patient populations afflicted with this disease.

Burkitt Lymphoma↗

PubMed1998

Pluripotent tumor cells in benign pituitary adenomas associated with multiple endocrine neoplasia type 1.

Analysis of human tumor cells in vitro enhances the study of numerous neoplastic conditions. However, it has been difficult to establish long-term cultures of adenoma cells, especially those of neuroendocrine origin, because the endocrine cells survive only briefly in culture, and fibroblasts overgrow the culture dish in 1 or 2 weeks. We describe cells isolated from pituitary adenomas in two patients with multiple endocrine neoplasia type 1 in which cells with a mesenchymal phenotype evolved from pituitary tumor cells. It appears that these poorly differentiated cells arose from multipotent adenoma cells. This represents a path of cell differentiation not observed previously in humans and may help explain the diverse nature of the benign tumors in multiple endocrine neoplasia type 1.

Adenoma↗