Phase properties of a zigzag chain lattice gas with Coulomb interactions

It has been reported that the phase transitions found in the quasi-one-dimensional sulfide KCu(7-x)S4 are most likely due to vacancy ordering involving Cu+-ion diffusion along the Cu(2)-Cu(2) zigzag chains. Our previous studies with both a self-consistent method and Monte Carlo simulations confirmed that phase transitions indeed exist in a one-dimensional (1D) lattice gas system in which vacancy ordering is involved. In this paper, we calculate the more nearly real case of KCu6.88S4 and further investigate the angular dependence of the phase properties in a partially occupied 1D zigzag chain with various particle occupancies. The calculated results suggest that the phase transitions that occur in the quasi-one-dimensional material KCu(7-x)S4 are presumably due to both intrachain and interchain interactions between the partially occupied Cu+ zigzag chains. Most interestingly, we found that the average particle distribution of the lowest free energy state is a linear superposition of two other solutions with different particle distributions for occupancy n(av)=1/2.

Overexpression of the HER-2/neu oncogene in pancreatic adenocarcinoma

Novel systemic treatments are needed in pancreatic cancer. The authors sought to establish the frequency of overexpression of the HER-2/neu oncogene in patients with pancreatic adenocarcinoma to determine the potential role of trastuzumab (Herceptin) as a therapeutic agent in this disease. Tumor specimens from patients with pancreatic adenocarcinoma were analyzed by staining for p185HER2 protein using the DAKO immunohistochemical assay. Patients with and without HER-2/neu overexpression by immunohistochemistry were compared with respect to clinical and pathologic characteristics. HER-2/neu gene amplification was also evaluated by fluorescence in situ hybridization (FISH). Thirty-two of 154 patients (21%) had pancreatic adenocarcinoma that demonstrated HER-2/neu overexpression by immunohistochemistry. At initial diagnosis, 16% of resectable cancers, 17% of locally advanced cancers, and 26% of metastatic cancers were determined to have HER-2/neu overexpression. Three of 11 (27%) patients with HER-2/neu overexpression by immunohistochemistry had gene amplification by FISH. HER-2/neu overexpression occurs in a subset of pancreatic cancer. Evaluation of the efficacy of trastuzumab for patients with pancreatic cancer who overexpress HER-2/neu appears indicated.

p53 mutations do not predict response to paclitaxel in metastatic nonsmall cell lung carcinoma

BACKGROUND

In vitro data and animal studies suggest that paclitaxel may have a unique ability to activate tumor cell apoptosis in the absence of wild-type p53 function. The authors previously demonstrated that response to paclitaxel and concurrent radiation was not affected by p53 mutations in nonsmall cell lung carcinoma (NSCLC). We sought to determine whether p53 mutations affect response to paclitaxel alone in patients with metastatic NSCLC.

METHODS

Twenty-five patients with metastatic NSCLC who participated in Brown University Oncology Group protocols utilizing single-agent weekly paclitaxel had tumor tissue that was adequate for p53 analysis. Tumor tissue was evaluated for p53 gene mutations in exons 5 through 8 by single-strand conformation polymorphism analysis. Mutations were confirmed by direct sequencing of altered mobility polymerase chain reaction products.

RESULTS

Mutations in p53 were found in 8 of 25 patients (32%). The response rates of 75% for patients with tumors with p53 mutations and 47% for patients with wild-type p53 do not differ significantly (P = 0.12). The 1-year survival rates for patients with and without p53 mutation after treatment with weekly paclitaxel were 63% (95% confidence interval [CI], 31-100%) and 53% (95% CI, 33-86%), respectively.

CONCLUSIONS

p53 mutations do not adversely affect response to paclitaxel as a single agent in metastatic NSCLC. These results provide clinical support for in vitro observations that paclitaxel can bypass mutant p53 and lead to tumor cell death by alternate pathway(s). Paclitaxel should be considered as a component of treatment for patients with metastatic NSCLC with tumors that have p53 mutations.

The human B cell response to IL-13 is dependent on cellular phenotype as well as mode of activation

Normal mature quiescent human B lymphocytes, isolated as a function of buoyant density, require activation for up-regulation of IL-13R constituents. Cell activation through a combination of surface Ig and CD40 receptor ligation leads to the most substantial message production for IL-13Ralpha1. Functional consequences of this receptor variation, in initially quiescent cells, includes demonstrable effects on cellular proliferation in response to ligand exposure. Variations in the method of surface activation, with particular emphasis on the CD40 receptor, reveals that immobilized CD40 ligand may be sufficient, in and of itself, to up-regulate IL-13Ralpha1, which may bear significance for B-lymphocyte bystander proliferation. Regulation of the IL-13Ralpha1 protein and message also differs as a function of cellular phenotype. Although values are greater in memory than naive B cells, as they are initially isolated from extirpated tonsils, variations in the magnitude of message and protein, as a function of surface stimulation, are more substantial in the naive subset. The magnitude of variation in message production in naive cells is associated with a more vigorous proliferative response to IL-13 than seen in memory lymphocytes. The cellular response to IL-13, as a function of activation and phenotype, is the converse of that demonstrated for IL-2. Evaluation of proliferation, receptor message, ligand binding protein production, and the response to putatively synergistic cytokines reveals that IL-2 is the predominant lymphokine utilized by memory cells. This is in contradistinction to IL-13, which along with IL-4, are the predominant moieties for naive lymphocytes.

Characterization and localization to chromosome 7 of psihGABPalpha, a human processed pseudogene related to the ets transcription factor, hGABPalpha

GABP is a heteromeric transcription factor complex which consists of the ets related protein, GABPalpha, and the Notch-related protein, GABPbeta. We isolated a human genomic DNA fragment which is highly homologous and colinear with human GABPalpha cDNA, but which lacks introns. This processed pseudogene, psihGABPalpha, is expressed as RNA in U937 human myeloid cells, but a mutation at the site that corresponds to the ATG start methionine codon prevents its translation into protein. The pseudogene was localized to chromosome 7 using a somatic cell hybrid mapping panel and it is not syntenic with authentic GABPalpha, which was localized to chromosome 21. We have identified psihGABPalpha, a novel, GABPalpha-related processed pseudogene which is expressed as a RNA transcript in human myeloid cells.

Role of p53 and p16 gene alterations in determining response to concurrent paclitaxel and radiation in solid tumor

Molecular genetic alterations that disturb cell cycle regulation in tumor cells can affect their response to chemotherapeutic agents and radiation. Many genes that regulate the critical cell cycle checkpoint at G1S are altered in human tumors. These genetic changes can result in uncontrolled cellular proliferation, genetic instability, and altered response to radiation and chemotherapy. The p53 tumor suppressor gene serves a critical role at the G1S transition, where it can either block entry into S phase or activate programmed cell death (apoptosis) in response to DNA damage. p53 Gene mutations are common in human tumors and interfere with the activation of apoptosis in response to most chemotherapeutic agents. Paclitaxel is a potent chemotherapeutic agent that interferes with mitotic spindle function to block cells at G2M, the most radiosensitive phase of the cell cycle. Utilization of paclitaxel as a radiation sensitizer in vivo to treat aggressive, locally advanced neoplasms has resulted in high response rates and acceptable toxicity in protocols for non-small cell lung carcinoma, upper gastrointestinal tract carcinoma, and other malignancies. Recent evidence suggests that paclitaxel is unique in its ability to activate apoptosis in tumor cells with p53 mutations in vitro and in vivo. The p16(INK4a) (MTS-1, CDKN2) gene product acts in the same pathway as p53 to inhibit cell cycle progression at G1/S. p16(INK4a) is deleted and/or mutated in a significant fraction of human tumors, including pancreatic carcinoma. The effects of p16(INK4a) alterations in response to paclitaxel/radiation and the risk of systemic relapse are currently being evaluated. Information about molecular genetic alterations in individual tumors ultimately may be a critical factor in choosing between therapeutic options.

Fluorescence melting curve analysis for the detection of the bcl-1/JH translocation in mantle cell lymphoma

PCR amplification and product analysis for the detection of chromosomal translocations such as bcl-1/JH have traditionally been performed as a two-step process with separate amplification and product detection. PCR product detection has generally entailed gel electrophoresis, hybridization, or sequencing for confirmation of assay specificity. By using a microvolume fluorimeter integrated with a thermal cycler and the PCR compatible double-stranded DNA (dsDNA) binding dye SYBR Green I, we simultaneously amplified and detected bcl-1/JH translocation products by using rapid cycle PCR and fluorescence melting curve analysis. We analyzed DNA from 25 cases of lymphoproliferative disorders comprising 12 previously documented bcl-1/JH-positive mantle cell lymphomas, and 13 reactive lymphadenopathies. The samples were coded and analyzed in a blind manner for the presence of bcl-1/JH translocations by fluorescence melting curve analysis. The results of fluorescence analysis were compared with those of conventional PCR and gel electrophoresis. All of the 12 cases (100%) previously determined to be bcl-1/JH positive by conventional PCR analysis showed a characteristic sharp decrease in fluorescence at about 86 degrees C by melting curve analysis. For easier visualization of melting temperatures (Tm), fluorescence melting peaks were obtained by plotting the negative derivative of fluorescence over temperature (-dF/dT) versus temperature (T). Dilutional assays revealed that fluorescence melting curve analysis was more sensitive than conventional PCR and agarose gel electrophoresis with ultraviolet transillumination by as much as 40-fold. Our results indicate that nucleic acid amplification integrated with fluorescence melting curve analysis is a simple, reliable, sensitive, and rapid method for the detection of bcl-1/JH translocations. The feasibility of specific PCR product detection without electrophoresis or expensive fluorescently labeled probes makes this methodology attractive for studies in molecular pathology.

Rapid simultaneous amplification and detection of the MBR/JH chromosomal translocation by fluorescence melting curve analysis

Polymerase chain reaction (PCR) amplification and product analysis for the detection of chromosomal translocations, such as the t(14;18), has traditionally been a two-step process. PCR product detection has generally entailed gel electrophoresis and/or hybridization or sequencing for confirmation of assay specificity. Using a microvolume fluorimeter integrated with a thermal cycler and a PCR-compatible double-stranded DNA (dsDNA) binding fluorescent dye (SYBR Green I), we investigated the feasibility of simultaneous thermal amplification and detection of MBR/JH translocation products by fluorescence melting curve analysis. We analyzed DNA from 30 cases of lymphoproliferative disorders comprising 19 cases of previously documented MBR/JH-positive follicle center lymphoma and 11 reactive lymphadenopathies. The samples were coded and analyzed blindly for the presence of MBR/JH translocations by fluorescence melting curve analysis. We also performed dilutional assays using the MBR/JH-positive cell line SUDHL-6. Multiplex PCR for MBR/JH and beta-globin was used to simultaneously assess sample adequacy. All (100%) of the 19 cases previously determined to be MBR/JH positive by conventional PCR analysis showed a characteristic sharp decrease in fluorescence at approximately 90 degrees C by melting curve analysis after amplification. Fluorescence melting peaks obtained by plotting the negative derivative of fluorescence over temperature (-dF/dT) versus temperature (T) showed melting temperatures (Tm) at 88.85+/-1.15 degrees C. In addition, multiplex assays using both MBR/JH and beta-globin primers yielded easily distinguishable fluorescence melting peaks at approximately 90 degrees C and 81.2 degrees C, respectively. Dilutional assays revealed that fluorescence melting curve analysis was more sensitive than conventional PCR and agarose gel electrophoresis with ultraviolet transillumination by as much as 100-fold. Simultaneous amplification and fluorescence melting curve analysis is a simple, reliable, and sensitive method for the detection of MBR/JH translocations. The feasibility of specific PCR product detection without electrophoresis or utilization of expensive fluorescently labeled probes makes this method attractive for routine molecular diagnostics.

Molecular pathobiology of pancreatic adenocarcinoma

Pancreatic adenocarcinoma is a major cause of cancer death in the United States. Most cases are sporadic and are discovered at late stage when they are not curable by surgery. Information about the molecular biology of pancreatic adenocarcinoma has increased significantly in the last five years with the identification of alterations in the K-ras proto-oncogene and the p16INK4a, p53, FHIT, and DPC4 tumor suppressor genes in a high percentage of tumors. Pancreatic adenocarcinoma is not homogeneous genetically, however, and other genes are clearly involved in some sporadic and heritable tumors. This review summarizes recent data relating to the molecular biology of pancreatic adenocarcinoma with emphasis on features which may be of clinical significance for diagnosis and/or therapy. Molecular genetic alterations that disturb cell cycle regulation in tumor cells can affect their response to chemotherapeutic agents and radiation and many of these genes are targeted in pancreatic adenocarcinoma. Knowledge of these genetic alterations in individual tumors may allow selection of optimal therapeutic strategies for individual patients. Furthermore, molecular detection of oncogene and tumor suppressor gene mutations may find application as screening tests for pancreatic adenocarcinoma at least in high risk populations. Biological therapy aimed at specific oncogenes and tumor suppressor gene replacement therapy protocols for pancreatic adenocarcinoma are beginning and may offer promise in the future.

Splenic marginal zone cell lymphoma associated with clonal B-cell populations showing different immunoglobulin heavy chain sequences

Splenic marginal zone cell lymphomas (SMZCLs) are low-grade B-cell lymphomas that usually present with massive splenomegaly and subtle (subleukemic) peripheral blood involvement. Polymerase chain reaction (PCR) analysis of peripheral blood from a patient with subleukemic SMZCL showed evidence of two clonal immunoglobulin heavy chain (IgH) gene rearrangements. IgH PCR analysis of DNA derived from the patient's splenic neoplasm demonstrated a single clonal IgH rearrangement, which had a different electrophoretic mobility from either of the two PCR products detected in the patient's peripheral blood. Additional characterization of these PCR products by DNA sequencing demonstrated two independent IgH rearrangements in the peripheral blood, one of which used IgH joining region 6c (JH6C) and the other JH4. A different IgH rearrangement was present in the splenic tumor, which used JH4a. No sequences from the splenic neoplasm were detected in the peripheral blood and vice versa. This case illustrates that PCR might reveal monoclonal populations in peripheral blood unrelated to the presence of lymphoma in other anatomic compartments.

Molecular characterization of Warthin tumor

OBJECTIVE

Warthin tumor of the salivary gland is composed of oncocytic epithelium with a prominent follicular lymphoid infiltrate. The purpose of this study was to characterize the clonality of this lymphoid component by means of polymerase chain reaction technology.

STUDY DESIGN

DNA was isolated from paraffin-embedded tissue from 20 cases of typical Warthin tumor of the salivary gland and amplified by polymerase chain reaction to assess B- and T-cell clonality.

RESULTS

No dominant clonal populations were identified in any tumor. However, minor clonal expansions of both B and T cells were detected in up to 50% of tumors (immunoglobulin H, 50%; T-cell antigen receptor beta, 10%; T-cell antigen receptor gamma, 5%). No tumors showed evidence of bcl-2 proto-oncogene translocation, whereas 95% contained detectable Epstein-Barr virus DNA.

CONCLUSION

The B- and T-cell components of Warthin tumor are polyclonal with oligoclonal expansion of both T and B cells in some lesions.

Regulation of interleukin-13 receptor constituents on mature human B lymphocytes

Human B cells stimulated through both their immunoglobulin and CD40 receptors up-regulate 745 +/- 51 interleukin (IL)-13 ligand binding sites with an affinity of 0.91 +/- 0.08 nM within 24 h. IL-13 binds primarily to the IL-13Ralpha1 with subsequent sequestration of the IL-4Ralpha into the complex. IL-13Ralpha1 may also be found in those receptors capable of binding IL-4. gamma chain (gammac) participates in receptors capable of binding IL-4 but is not found in association with bound IL-13. Dimeric receptors composed of the IL-4Ralpha complexed with either the IL-13Ralpha1 or gammac occur simultaneously within defined B cell populations. mRNAs for all receptor constituents are increased subsequent to immunoglobulin stimulation alone, while maximal expression of IL-13Ralpha1 is more dependent upon co-stimulation of immunoglobulin and CD40 receptors. mRNA levels for IL-13Ralpha1 vary over a wider range subsequent to surface stimulation than other receptor components. Although gammac is not bound to IL-13 in B cells under the conditions evaluated, it may influence IL-13 binding by competing with IL-13Ralpha1 for association/sequestration with the IL-4Ralpha chain. IL-13Ralpha2 does not participate in the IL-13 receptor that is up-regulated upon activation of quiescent tonsillar B lymphocytes, although mRNA for the protein may be found in the centroblastic fraction of tonsillar cells.

Whole blood screening test for factor V Leiden using a Russell viper venom time-based assay

Factor V Leiden (FVR506Q) is a genetic defect in the factor V (FV) molecule that confers resistance to proteolysis by activated protein C (APC) and is the most common abnormality detected in patients studied for hereditary thrombophilia. The initial screening test for this abnormality was a comparison of the activated partial thromboplastin time (APTT) in the presence and absence of APC, expressed as a ratio. But this has been shown to lack sensitivity for the FV mutation. Other clot-based screening tests, such as the modified APTT, using FV-deficient plasma, or the Russell viper venom (RVV) time assay have improved sensitivity. Eighty-seven samples were studied using the RVV-based assay. This assay was performed on platelet-poor plasma (PPP-RVV) and whole blood (WB-RVV). All samples were analyzed by polymerase chain reaction (PCR) for the FV Leiden defect: 77 were PCR negative; 10 were PCR positive. Using a threshold ratio of 1.8, all samples were correctly categorized in the PPP-RVV and the WB-RVV tests, showing an observed sensitivity and specificity of 1.0. These results suggest that an RVV-based assay using whole blood could be an effective screening test for this common abnormality.

Localization of 2 11beta-OH steroid dehydrogenase isoforms in aortic endothelial cells

11Beta-hydroxysteroid dehydrogenase (11beta-HSD) is expressed in vascular smooth muscle cells (VSMC) but has not been reported to be present in vascular endothelial cells. This enzyme assists in regulating the cellular concentration of active endogenous glucocorticoids (GCs). We have observed that endothelium intact rat aortic rings express message for both Type 1 and Type 2 11beta-HSD whereas primary cultures of VSMC express only mRNA for the Type I isoform. Since GCs diminish prostacyclin synthesis in endothelial cells, we hypothesized that 11beta-HSD is present in vascular endothelial cells. In primary cultures of rat aortic endothelial (RAE) cells, mRNA from both isoforms of 11beta-HSD could be detected by RT-PCR with higher levels of the Type 1 isoform. The oxo-reductase reaction "activating" 11-dehydro metabolites back to the parent steroid is the preferred enzyme direction (12:1 after a 120 minutes steroid incubation) in intact RAE cells. When RAE cells are grown in the presence of antisense oligonucleotides specific for Type 1 11beta-HSD, oxo-reductase activity is decreased by approximately 50% but the dehydrogenase reaction, which inactivates endogenous GCs and is characteristic of the Type 2 isoform, is unaffected. Thus endothelial cells appear to express both isoforms of 11beta-HSD; the Type 1 isoform dominates functioning in the oxo-reductase mode. Inhibition of the oxo-reductase reaction may lower the local concentrations of GC and indirectly allow for increased production of prostacyclin in endothelial cells.

Aprotinin, cardiac surgery, and factor V Leiden

BACKGROUND

Aprotinin has been shown to reduce blood transfusion in cardiac surgery. Aprotinin inhibits activated protein C (APC). Patients with factor V (FV) Leiden have an inherited resistance to APC proteolysis. If the inhibition of APC by aprotinin contributes to its beneficial effect in cardiac surgery, then patients with FV Leiden undergoing cardiac surgery might be expected to require less transfusion than patients without FV Leiden. However, the use of aprotinin in such patients also could compromise the protein C regulatory pathway and precipitate a clinical thrombotic event.

STUDY DESIGN AND METHODS

Patients undergoing cardiac surgery were studied for the presence of the FV Leiden defect by the use of a Russell's viper venom clot-based assay and polymerase chain reaction. The total amount of blood transfused was recorded for each patient. The effect of aprotinin on the plasma of normal and FV Leiden patients was studied. Further studies were performed on the direct inhibition of APC by aprotinin.

RESULTS

Over an 18-month period, 162 patients were studied, of whom 13 (8%; 95% CI, 4.3-13.3%) were positive for FV Leiden. These 13 had a smaller requirement for blood transfusion than the to 13 matched controls. In vitro, aprotinin induced a FV Leiden defect in normal plasma and exacerbated the defect in the plasma of FV Leiden patients. Aprotinin inhibited APC in a dose-dependent manner, and kinetic analysis showed competitive inhibition with an inhibition constant of 4.5 microM (250 Kallikrein inhibitor units/mL).

CONCLUSION

The inhibition of APC by aprotinin may contribute to its hemostatic effect. The use of aprotinin in patients with FV Leiden could cause extreme dysfunction of the protein C regulatory pathway, which could result in clinical thrombosis.

Comparison of an activated partial thromboplastin time with a Russell viper venom time test in screening for factor V(Leiden) (FVR506Q)

Factor V(Leiden) is the most common abnormality detected in patients examined because of hereditary thrombophilia. The most widely used clot-based screening test is based on the activated partial thromboplastin (aPTT) time. This test has a low sensitivity. A comparison of the aPTT-based test with a Russell viper venom time test (RVVT) was performed in matched samples. All samples were analyzed by polymerase chain reaction (PCR) for the factor V(Leiden) defect. We studied 139 samples, of which 109 were PCR-negative; 30 were PCR-positive. Using the manufacturer's suggested threshold ratio of 2, the aPTT test showed a sensitivity of 0.43, a specificity of 0.86, and a positive predictive value (PPV) of 0.97. The RVVT test had a sensitivity of 1.0, a specificity of 0.95, and a PPV of 0.91. Segregation of a subpopulation of this study population into ABO group O vs non-group O showed an effect of ABO group on the aPTT test but not on the RVVT test, consistent with an influence of factor VIII clotting (factor VIII:C) on the aPTT test. The RVVT test seems superior to the unmodified aPTT test as a screening test for factor V(Leiden).

P53 expression in Reed-Sternberg cells does not correlate with gene mutations in Hodgkin's disease

Immunohistochemically detectable p53 protein expression is common in the Reed-Sternberg and Hodgkin's (RS-H) cells of Hodgkin's disease, but p53 gene mutations have only rarely been identified. The authors found p53 expression in RS-H cells in 16 of 30 cases of Hodgkin's disease (53%), with the percentage of RS-H positive cells ranging from 4% to 85%. In 12 of 30 cases (40%), at least 10% of the RS-H cells were positive for p53. p53 gene mutations were detected in only two cases (7%) using a single-stranded conformational polymorphism assay with a detection sensitivity of between 1% and 5%. The cellular protein, mdm-2, which can stabilize and functionally inactivate wild-type p53 protein, was expressed in RS-H cells in most of these cases (86%). However, neither case with a p53 gene mutation expressed mdm-2 (P < .005). The two cases with p53 gene mutations had a higher mean proliferative index than cases without detectable mutations (90% versus 72%; P < .02). p53 expression in RS-H cells may be related to concurrent mdm-2 protein expression and a p53-positive, mdm-2-negative immunophenotype may be predictive of gene mutations in RS-H cells.

Synchronous colon carcinomas: molecular-genetic evidence for multicentricity

BACKGROUND

The synchronous presentation of multiple colonic adenocarcinomas is an unusual, but well-recognized event accounting for approximately 2-11% of these neoplasms. Synchronous tumors may have a different biology and prognosis than solitary tumors. Evidence based on measurement of DNA ploidy suggests that a significant percentage of synchronous tumors have a common clonal origin, probably resulting from translumenal metastasis.

METHODS

Fifteen synchronous colorectal cancers (30 tumors) were examined for histologic differences as well as genetic mutations. p53 gene abnormalities were detected by polymerase chain reaction (PCR) followed by single-strand conformation polymorphism analysis. Ki-ras mutations were detected by PCR followed by oligonucleotide-specific hybridization.

RESULTS

p53 gene mutations were detected in 12 of 30 tumors. In only one case was the same p53 mutation present in both tumors from one patient. Similarly, Ki-ras mutations were observed in 9 of 30 tumors. Concordant Ki-ras mutations were observed in only one case, which was also concordant for p53 mutation.

CONCLUSION

Because p53 and Ki-ras mutations tend to occur fairly early in tumor development, it seems likely that cases discordant for p53 and Ki-ras mutations represent independently developing tumor foci. Taken together, these findings strongly suggest that the great majority of synchronous colonic adenocarcinomas arise as independent neoplasms and their worsened prognosis is not a result of unusually early metastatic spread.

Monoclonal B-cell population mimicking lymphoma in a patient with multiple sclerosis

BACKGROUND

Diagnosis of intraparenchymal brain lesions has usually required invasive diagnostic procedures, because too few cells are shed into cerebrospinal fluid to permit cytologic diagnosis. Polymerase chain reaction technology makes it possible to identify cell populations that are present at a much lower frequency than traditional techniques.

CASE REPORT

A young woman presented with multiple brain lesions raised the question of primary central nervous system lymphoma. Polymerase chain reaction analysis of cerebrospinal fluid showed evidence of a monoclonal B-cell population heightening suspicion of lymphoma. Brain biopsy showed acute demyelination most consistent with multiple sclerosis.

CONCLUSION

Although T-cell restriction has been demonstrated in multiple sclerosis lesions, the finding of a monoclonal B-cell population was unexpected and to our knowledge has not been previously reported. This case emphasizes that monoclonality is not always indicative of a neoplastic process, particularly in the central nervous system.

Extramedullary myeloid cell tumors arising in the setting of chronic myelomonocytic leukemia. A report of two cases

We report two cases of extramedullary myeloid cell tumor that arose in patients with chronic myelomonocytic leukemia. In both cases, the tumors were difficult to recognize histologically because the neoplasms lacked cytological evidence of granulocyte maturation, such as cytoplasmic granulation or eosinophilic myelocytes, and the Leder stains for chloroacetate esterase were negative. Immunohistochemical studies were necessary to establish the correct diagnosis. The neoplastic cells in both tumors expressed myeloperoxidase, lysozyme, and CD43 and were negative for B-cell, T-cell, and other nonhematopoietic antigens tested. We report these cases to emphasize that extramedullary myeloid cell tumors may rarely precede transformation to acute myeloid leukemia in patients with chronic myelomonocytic leukemia. Extramedullary myeloid cell tumors of monocytic lineage may be difficult to recognize in routine and Leder-stained sections, and immunohistochemical studies may be essential for establishing the diagnosis.

Retrospective diagnosis of sickle cell-hemoglobin C disease and parvovirus infection by molecular DNA analysis of postmortem tissue

A previously healthy 30-year-old African-American woman presented with a history of sickle cell trait and a nonspecific prodromal illness with severe bone pain. She experienced rapid clinical deterioration with seizures and cardiorespiratory arrest leading to death. Autopsy showed necrotic bone marrow with extensive bone marrow emboli. Parvovirus infection was documented by polymerase chain reaction (PCR) although diagnostic intranuclear inclusions or giant pronormoblasts were not present. The diagnosis of sickle cell-hemoglobin C disease (hemoglobin SC disease) was also established postmortem by DNA sequencing of PCR products. This case illustrates the use and versatility of PCR for analysis of formalin-fixed paraffin-embedded autopsy tissue.

Fluorescent in situ hybridization for assessing the proportion of cells with trisomy 4 in a patient with acute non-lymphoblastic leukemia

A case of acute non-lymphoblastic leukemia is described in which fluorescent in situ hybridization (FISH) helped to resolve initially conflicting conventional cytogenetic results. Identification and assessment of the proportion of cells exhibiting trisomy of chromosome 4 in the patient's bone marrow were made using a probe which hybridizes to the centromeric region of chromosome 4. These FISH results were consistent with our retrospective GTG-banded analysis but differed from another study conducted elsewhere. Factors such as culture conditions and duration of culture which may have influenced the proportion of leukemic to nonleukemic cells are discussed. Fluorescent in situ hybridization is a powerful adjunct to conventional cytogenetic analysis and may prove to be a useful tool for monitoring minimal residual disease in this patient.

Isolated metastasis to a pulmonary hamartoma

Intrapulmonary hamartomas are the most common benign pulmonary neoplasm, and malignant degeneration is exceedingly rare. Only a minority produce symptoms, and their major clinical significance is their ability to simulate a malignant pulmonary neoplasm in radiologic studies. Here we report a case of apparently localized prostatic adenocarcinoma with isolated metastasis to an intrapulmonary hamartoma. The pulmonary lesion was identified during staging and was ultimately resected. Prostatic adenocarcinoma involved the hamartoma extensively but did not involve adjacent lung tissue. The hamartoma was otherwise typical with predominantly cartilaginous differentiation. The malignant glands within the hamartoma showed strong reactivity for prostate specific antigen, excluding the possibility of malignant change within the hamartoma. To our knowledge, metastasis to a pulmonary hamartoma has not been previously reported, and this case raises several issues. The pattern of tumor spread suggests an affinity of the tumor cells for the hamartoma. The known propensity of prostatic adenocarcinoma to metastasize to osseous sites might underlie its apparent tropism for the cartilaginous milieu of a pulmonary hamartoma. Accurate pathologic staging of this patient's prostatic adenocarcinoma prevented a needless radical prostatectomy, and complete cancer staging may require histologic examination of clinically typical pulmonary hamartomas.

Lymphoma of the mucosa-associated lymphoid tissue of the lung. A multifocal case of common clonal origin

Low-grade B-cell lymphomas of the mucosa-associated lymphoid tissue (MALT) are extranodal tumors that tend to be localized. In this case report, the authors describe an unusual multifocal pulmonary MALT lymphoma, which presented radiologically as three discrete lesions involving two separate lobes of the lung, in addition to numerous separate macroscopic and microscopic foci of disease. The lesions were composed of centrocyte-like cells and cytologically bland plasma cells surrounding reactive lymphoid follicles with focal areas resembling lymphoid interstitial pneumonia (LIP). Immunohistochemical studies demonstrated a predominance of immunoglobulin kappa light chain positive plasma cells in the largest lesion. A polymerase chain reaction (PCR) assay demonstrated conserved immunoglobulin heavy chain gene rearrangements in the large tumor nodules as well as microscopic foci resembling LIP. This case illustrates the utility of PCR for identifying the clonal nature of lymphoid lesions that are too small or heterogeneous to unequivocally assess by other means.

Occult diaphragm injuries at celiotomy for left chest stab wounds

No dependable test exists for diagnosis of diaphragmatic injury in asymptomatic patients with thoraco-abdominal stab wounds. Forty-one consecutive patients with anterior stab wounds of the lower left chest were treated in a 30-month period. In the 21 patients seen during the first 15 months, operations were reserved for those with peritoneal signs or continuing blood loss. Ten of these 21 patients (48%) required celiotomy; 2 patients (10%) had isolated diaphragm injuries and there was one negative celiotomy. Of the eleven patients who were not explored, 2 (18%) returned within 18 months after injury with an incarcerated diaphragmatic hernia. During the subsequent 15 months, the next 20 patients were managed by routine celiotomy in a prospective study. The admission systolic blood pressure and incidence of pneumothorax, celiotomy, diaphragm injury, isolated diaphragm injury, and unnecessary celiotomy in these two groups were compared. Ten patients in the prospective group (50%) were found to have isolated diaphragm injuries (P less than 0.005) and 7 (35%) had negative celiotomies (P less than 0.02). The true incidence of occult diaphragm injuries may be underestimated. In the prospectively studied group, the policy of routine celiotomy for anterior stab wounds of the lower left chest resulted in recognition and repair of a fivefold greater number of isolated diaphragm injuries. In the absence of a reliable, noninvasive test to diagnose penetration of the diaphragm, celiotomy should be considered in light of the risks of late strangulation.

Evaluation of a topically administered carbonic anhydrase inhibitor (MK-927) in normotensive and glaucomatous beagles

A new topically administered anhydrase inhibitor, MK-927, was evaluated for its ocular hypotensive activity in normotensive and glaucomatous Beagles. Single- and multiple-dose studies were performed. Six concentrations of the drug were evaluated in the single-dose study and the 2% solution was used for multiple-dose evaluation. The decrease in intraocular pressure (IOP) was greater in glaucomatous Beagles at the higher concentrations of the drug. The 2 and 4% solutions of MK-927 significantly lowered IOP (mean, 5 mm of Hg; SEM +/- 1.6 and SEM +/- 1.2, respectively) in normotensive and glaucomatous Beagles. In the multiple-dose study, IOP was significantly decreased in the normotensive (mean, 4 mm of Hg; SEM +/- 0.74) and glaucomatous Beagles (mean, 9 mm of Hg; SEM +/- 1.2). The maximal effect was observed by day 4. A contralateral effect was found in glaucomatous Beagles, with the maximal effect on day 4.

Therapeutic management of ocular squamous cell carcinoma in the horse: 43 cases (1979-1989)

The records of 50 horses with ocular squamous cell carcinoma (OSCC) presented to the University of Florida Veterinary Medical Teaching Hospital over an 11 year period were reviewed to determine the influence of therapy on the outcome of the case. Follow-up information was obtained for 43 of the 50 cases. The disease was more prevalent in the light horse breeds; however, the draft breeds also were at risk. There was no sex predisposition and the average age was 11.8 years. Tumour recurrence was significant when surgery alone was performed. The eyelid and nictitating membrane were the primary sites for tumor recurrence. Cases in which adjunctive therapy was used correlated with a lower rate of recurrence.

Integration of quality assurance activities into a computerized patient data management system in an intensive care unit

A prototype computer-based patient data management system (PDMS) was developed for a surgery-anesthesiology intensive care unit (ICU) to reduce the time and staff needed to implement quality assurance (QA) functions. Goals of the system were to make QA functions routine and minimally intrusive to the daily operation of the ICU. PDMS collects general data (eg, admissions and discharges, lengths of stay, and bed utilization rates) and specialized data (eg, specific indicators) unique to the ICU and performs prospective monitoring for the occurrence of specific events (occurrence screening) and retrospective examinations of patient records (targeted reviews). Preliminary results suggest that PDMS facilitates the acquisition and analysis of QA data and reduces the time needed to acquire these data. Research to validate these claims and efforts to improve and expand the prototype system with a permanent production system are in progress.

Hydroxyethyl starch macromolecules reduce myocardial reperfusion injury

We assessed the value of a fraction of hydroxyethyl starch (HES Pz) in reducing the myocardial reperfusion injury in a canine open-chest model in which 1 hour of left anterior descending coronary artery occlusion was followed by 24 hours of reperfusion. Three treatment infusions (5% of blood volume) were compared: Ringer's lactate, serum albumin, and HES Pz (70% of the macromolecules between 100,000 and 1,000,000 d). When compared with Ringer's lactate and albumin, HES Pz significantly reduced the ratio of 24-hour infarct size to pretreatment area at risk (3% vs 19% and 16%, respectively) and myocardial water content (0.5% vs 3% and 1%). Potassium content differences between injured and normal myocardium were significantly less in the infarct regions of animals receiving HES Pz. In the canine model, HES Pz reduced 1-hour myocardial ischemia reperfusion injury significantly.

A biophysical approach to capillary permeability

In this preliminary report, the capillary leakage that occurs after scald injury is considered a biophysical phenomenon and is treated by sealing the "pores," or endothelial gaps, in the capillary membranes with biodegradable macromolecules of the appropriate size and shape. We have measured albumin leakage from standardized scald burns in the rat jejunum with and without variously sized fractions of intravenous macromolecules of hydroxyethyl starch (HES) used as a sealing agent. The observed reduction of albumin leakage from injured capillaries was attributed to the sealing effect. The fraction HES (Fm) with molecular weights of 100,000 to 300,000 daltons performed significantly better (p less than 0.05) as a sealing agent when compared with HES (F1) fraction molecular weights of 300,000 to 3.4 million daltons, HES (Fs) molecular weight less than 50,000 daltons, and two control groups receiving the intravenous Ringer's lactate solution or serum albumin 5%. This capillary sealing phenomenon was shown to be independent of colloid osmotic pressure effect. It is believed to be related to the size and the shape of the noncharged macromolecules.

Structure of the NGFI-A gene and detection of upstream sequences responsible for its transcriptional induction by nerve growth factor

The NGFI-A gene encodes a "zinc-finger" protein that is rapidly induced by nerve growth factor (NGF) in PC12 rat pheochromocytoma cells. The complete exon/intron organization and nucleotide sequence of the rat NGFI-A gene have been determined. The gene spans 3789 nucleotides (nt) and is interrupted by a single intron at nt 588. All three zinc-finger DNA-binding domains are contiguously coded for within the 3' exon; this is in contrast to the structure described by others for the Xenopus laevis transcription factor TFIIIA gene. To analyze the transcription of this gene, we have determined the transcription start site and nucleotide sequence of the 5' flanking region. Transfection of PC12 cells with a fragment from the 5' flanking region linked to the chloramphenicol acetyltransferase (CAT) gene revealed that it contains an element which imparts an NGF-inducible phenotype to the normally silent CAT gene. Several regions with homologies to recognizable sequence elements are present in this fragment, including a TATA box at nt -27, serum response elements at nt -84, -106, -370, and -408, a cAMP-responsive element at nt -140, and a transcription factor Sp1-binding site at nt -286. These results establish the genomic structure of this mammalian multifinger protein and demonstrate that an NGF-responsive element lies upstream of the NGFI-A gene.

Papillary cystadenoma of the mesosalpinx in von Hippel-Lindau disease

Papillary cystadenoma of the epididymis is an occasional finding in men with von Hippel-Lindau disease. To date, an analogous lesion has not been described in women with the syndrome. We report a case of an asymptomatic papillary cystadenoma of the mesosalpinx found incidentally during surgery for a renal cell carcinoma in a woman with von Hippel-Lindau disease. This finding supports the notion that similar lesions may arise in both men and women with von Hippel-Lindau disease, perhaps from embryologically related portions of the urogenital tract.

The bovine mitochondrial endonuclease prefers a conserved sequence in the displacement loop region of mitochondrial DNA

The purified endonuclease of bovine heart mitochondria shows a remarkable preference for a specific site in bovine mtDNA. This site was identified using a recombinant DNA template which includes a 4.9-kilobase portion of the 16-kilobase bovine mitochondrial sequence encompassing all of the displacement loop region. The endonucleolytic target corresponds to an evolutionarily conserved sequence tract of 12 consecutive guanine residues that is found in an otherwise highly divergent domain of the mitochondrial displacement loop region. The preference for this site is several hundred-fold greater than other less favored sites. Unlike other less prominent cleavage loci, the conserved sequence tract is readily nicked in either or both DNA strands, even at 0 degrees C. These findings suggest that there is a specific interaction of the endonuclease with this site in vivo that may be important for mtDNA replication.

Mapping of control elements in the displacement loop region of bovine mitochondrial DNA

The genomes of mammalian mitochondria are duplex DNA circles. The two major transcriptional promoters and the origin of DNA replication for one DNA strand are located in a single region which contains no structural genes and occupies about 6% of the genome. This region is called the displacement loop (D-loop) region since it is often found as a novel triplex structure in which the heavy strand of the genome has been partially replicated. This nascent single-stranded DNA segment remains hybridized to the light strand, displacing the heavy strand of the genome over much of the D-loop region. The promoters and the sites of initiation of D-loop DNA synthesis have been mapped in the human and mouse genomes and may show limited sequence conservation. We have mapped these sites in the bovine mitochondrial genome. Some features are conserved between all three species; however, the promoters and the sites of initiation of D-loop DNA synthesis show no primary sequence homology among all species. This lack of sequence homology is in contrast to the greater than 80% sequence conservation which has been reported in portions of the D-loop region which are located distal to the origin of DNA replication and far from the transcriptional promoters. These results imply that closely related species may have developed different means of controlling mitochondrial gene expression.

Mitochondrial DNA displacement loop structure depends on growth state in bovine cells

One portion of the mitochondrial genome of mammals contains no structural genes. This so-called displacement loop (D-loop) region includes the two major transcriptional promoters and one of the origins of DNA replication. The D-loop region is often found in a novel triplex structure in which a discrete single-stranded DNA segment is hybridized to one strand of the genome displacing the other strand. The significance of this triplex structure and the possible function of the single-stranded D-loop segment have remained obscure. Here we show that the locations of the major 5' termini of D-loops in growing and nongrowing bovine cells differ by 46 nucleotides. The location of bovine D-loop 5' termini is dependent on the cell cycle but is not directly linked to nuclear DNA replication. The nature of D-loop 5' termini in growing cells is altered by inhibitors of cytoplasmic protein synthesis but not by inhibitors of mitochondrial protein synthesis. Changes in D-loop 5' termini correlate with alterations in transcripts from one of the transcriptional promoters. These findings implicate D-loops in the control of bovine mitochondrial gene expression and suggest mechanisms by which this control might by accomplished.

Purification and characterization of the potent endonuclease in extracts of bovine heart mitochondria

A potent endonuclease identified in a crude fraction of soluble proteins from bovine heart mitochondria has been purified 2500-fold and partially characterized. Physical studies of the enzyme indicate a Stokes radius of 30.3 A and a sedimentation coefficient, S20 degrees, w, of 4.1 yielding a native molecule weight of 59,000 and a frictional coefficient of 1.2. Analysis of extensively purified fractions by sodium dodecyl sulfate-polyacrylamide gel electrophoresis reveals a major band at 29,000 Da accounting for 50% of the total protein and suggesting a dimeric subunit structure. The endonuclease maintains two distinct pH optima: pH 5.1-5.5 and 7-8. Both acid and neutral activities nick supercoiled M13 circular double-stranded replicative form I DNA and fragment single-stranded DNA templates to generate 5'-phosphoryl-3'-hydroxyl breaks. The endonuclease requires a divalent cation (preferring Mn2+ over Mg2+) and is sensitive to N-ethylmaleimide and moderate levels of salt. Analysis of the digestion products of double-stranded DNA after prolonged nuclease treatment yields a mixture of oligonucleotides, 13% of which are di- and trinucleotides. Despite the enzyme's ability to degrade DNA to oligonucleotides under some conditions, a strikingly nonrandom pattern of cleavage is observed when a restriction fragment composed of bovine D-loop DNA is used as a template. In this case, a strong preference for guanine tracts is seen.

Complete transection of the intrathoracic trachea due to blunt trauma

A 24-year-old man was transferred to Columbia-Presbyterian Medical Center from a local hospital 24 hours after a car crash. Bronchoscopy at the local hospital revealed transection with discontinuity of the trachea just above the carina. At Columbia-Presbyterian Medical Center, following cautious intubation without positive airway pressure, a right posterolateral thoracotomy was performed, and the bronchi were intubated with sterile endotracheal tubes for initial airway control. A 6-cm tracheal disruption was repaired. Early care was complicated by chest wall instability and pulmonary contusions, but the patient was discharged breathing comfortably on the tenth postoperative day. Subsequent to discharge, flow-volume loops revealed the development of a tracheal stricture. Three months after the initial procedure, tracheal resection for stenosis was completed. To date, the patient is asymptomatic.

The role of brain stimulation priming effects in self-deprivation

Choice of brain stimulation reward (BSR) over biologically necessary substances in some self-stimulating animals is referred to as self-deprivation. In several recent papers, it has been argued that this phenomenon is produced by the rewarding aspects of the brain stimulation. This conclusion is partially based on data showing that self-deprivation and brain stimulation reward increase and decrease in a similar manner in response to changes in the brain stimulation parameters. However, the priming aspects of the brain stimulation also fluctuate with changes in stimulation parameters. Therefore, changes in the priming rather than the rewarding aspects of the brain stimulation could be responsible for self-deprivation. To determine whether the priming effects of brain stimulation play an important role in self-deprivation, rats with bipolar stimulating electrodes were given the choice between BSR and food. Time-outs were enforced within each BSR/food competition session. Since priming effects decay over time, increasing time-out length should have decreased self-deprivation due to decay of priming. It was found that time-out length did not affect the degree of self-deprivation. It was concluded that self-deprivation is not mediated by the priming aspects of brain stimulation.

RNase III cleavage is obligate for maturation but not for function of Escherichia coli pre-23S rRNA

RNase III makes the initial cleavages that excise Escherichia coli precursor 16S and 23S rRNA from a single large primary transcript. In mutants deficient in RNase III, no species cleaved by RNase III are detected and the processing of 23S rRNA precursors to form mature 23S rRNA fails entirely. Instead, 50S ribosomes are formed with rRNAs up to several hundred nucleotides longer than mature 23S rRNA. Unexpectedly, these aberrant subunits function well enough to participate in protein synthesis and permit cell growth. Consistent with the inference that RNase III cleavages are absolutely required for 23S rRNA maturation, when 50S ribosomes from a strain deficient in RNase III were incubated with a ribosome-free extract from a RNase III+ strain, rRNA species processed by RNase III and species with normal mature 23S rRNA termini were produced.

S1 nuclease mapping analysis of ribosomal RNA processing in wild type and processing deficient Escherichia coli

S1 nuclease mapping was used to assess rRNA processing in Escherichia coli. Single-stranded DNA probes complementary to the sequences bordering each terminus of 16 S and 23 S rRNA were end-labeled, hybridized to total E. coli RNA, and treated with S1 nuclease. The resultant DNA fragments were then displayed on denaturing polyacrylamide gels. Measurements of steady state levels of precursor rRNA species and measurements of the rates of decay of precursors after transcription arrest by rifampicin gave consistent results. 1) The rRNA precursor species identified in wild type cells corresponded to those previously identified by other means. 2) In RNase III-deficient strains, mature 16 S rRNA termini form at the same rate as in wild type cells; but the normal mature termini of 23 S rRNA are never generated. 3) RNase III cleavage at the 5' end of 23 S rRNA can occur before the 3' end of the same molecule is synthesized. 4) The cleavages that generate the mature termini of 16 S rRNA are interdependent; in the BUMMER strain, slow processing at the 5' end is accompanied by slow processing at the 3' end. Thus, the kinetically observed order of processing reactions is obligate for some cleavages but not for others, and the assumption that complete rRNA processing is required for function fails for 23 S rRNA.

Structure of partially denatured Escherichia coli 23 S ribosomal RNA determined by electron microscopy

The secondary structure of 23 S ribosomal RNA was analyzed by electron microscopy after partial denaturation. A reproducible pattern of loops was seen when molecules were spread for electron microscopy in 50% formamide solutions containing various concentrations of Mg2+ and Na+. Some loops were stabilized more than others by Na+ or by Mg2+; but in general, small amounts of Mg2+ (0.5 to 1.0 mM) markedly stabilized all the major loops, as did much greater amounts of Na+ (100 mM). However, at all levels of Mg2+ examined, increasing levels of Na+ destabilized loop structures. These data are consistent with the known salt dependence of double-stranded DNA and transfer RNA structure. The four most frequently observed loops correspond, within the limits of measurement error, to the major loops in the secondary structure models of Noller et al. (1981) and Glotz et al. (1981). These four loops are, in length and position of their midpoints along the 23 S rRNA molecule: 490 +/- 50 at 250 +/- 40; 350 +/- 50 at 1860 +/- 80; 400 +/- 70 at 2330 +/- 150; and 570 +/- 100 at 2350 +/- 100. Three of the four have base-paired stems with delta G0 values among the lowest of all the loops in the two indirect models. At least two are also among the most stable loops found in computer searches of the 23 S rRNA sequence for dyad symmetry. These results demonstrate that partial denaturation mapping can both identify prominent features of secondary structure in rRNA and estimate their relative stability.

Spectrophotometric assessment of dose-response curves for single antimicrobial agents and antimicrobial combinations

The activity of single antimicrobial agents and antimicrobial combinations was examined by measuring their effects on the growth rate constant of a test strain of Escherichia coli. This spectrophotometric method provides a kinetic view of antimicrobial action and is sufficiently precise to define dose-response curves, in contrast to standard methods such as broth or agar dilution testing, which are static and measure only all-or-none responses. The results demonstrate that dose-response curves for single antimicrobial agents are logarithmic (rather than linear) and that the effects of antimicrobial combinations may be exquisitely concentration dependent. Although the results for some antimicrobial combinations were similar with the spectrophotometric and checkerboard methods, other combinations produced different results in the two systems. Additional studies will be necessary to determine whether one or the other of these methods more accurately predicts clinical outcome.