CHARMM: the biomolecular simulation program

CHARMM (Chemistry at HARvard Molecular Mechanics) is a highly versatile and widely used molecular simulation program. It has been developed over the last three decades with a primary focus on molecules of biological interest, including proteins, peptides, lipids, nucleic acids, carbohydrates, and small molecule ligands, as they occur in solution, crystals, and membrane environments. For the study of such systems, the program provides a large suite of computational tools that include numerous conformational and path sampling methods, free energy estimators, molecular minimization, dynamics, and analysis techniques, and model-building capabilities. The CHARMM program is applicable to problems involving a much broader class of many-particle systems. Calculations with CHARMM can be performed using a number of different energy functions and models, from mixed quantum mechanical-molecular mechanical force fields, to all-atom classical potential energy functions with explicit solvent and various boundary conditions, to implicit solvent and membrane models. The program has been ported to numerous platforms in both serial and parallel architectures. This article provides an overview of the program as it exists today with an emphasis on developments since the publication of the original CHARMM article in 1983.

Presentation and management of perineal endometriosis

OBJECTIVE

To analyze the clinical presentation of perineal endometriosis and evaluate its treatment.

METHODS

Clinical data were analyzed from the records of 36 patients with perineal endometriosis who were operated on between 1983 and 2007 at Peking Union Medical College Hospital, and followed up for 0.5 to 14 years.

RESULTS

The incidence of perineal endometriosis was 0.31% among the women with endometriosis treated surgically at the hospital. The latent period was between 4 months and 13 years. All patients had cyclical and painful lesions. Of the 36 patients, 5 (13.9%) also suffered from pelvic endometriosis. All patients without anal sphincter involvement were cured after complete surgical excision. In 7 patients who had anal sphincter involvement, disease recurred because of incomplete excision.

CONCLUSION

Perineal endometriosis can be diagnosed on the basis of clinical features and surgical excision is the treatment of choice. The recurrence rate of perineal endometriosis is related to sphincter involvement making preoperative evaluation of anal sphincter important.

The role of macrophages in optic nerve regeneration

Following injury to the nervous system, the activation of macrophages, microglia, and T-cells profoundly affects the ability of neurons to survive and to regenerate damaged axons. The primary visual pathway provides a well-defined model system for investigating the interactions between the immune system and the nervous system after neural injury. Following damage to the optic nerve in mice and rats, retinal ganglion cells, the projection neurons of the eye, normally fail to regenerate their axons and soon begin to die. Induction of an inflammatory response in the vitreous strongly enhances the survival of retinal ganglion cells and enables these cells to regenerate lengthy axons beyond the injury site. T cells modulate this response, whereas microglia are thought to contribute to the loss of retinal ganglion cells in this model and in certain ocular diseases. This review discusses the complex and sometimes paradoxical actions of blood-borne macrophages, resident microglia, and T-cells in determining the outcome of injury in the primary visual pathway.

The Effects of Open Lung Ventilation on Respiratory Mechanics and Haemodynamics in Atelectatic Infants after Cardiopulmonary Bypass

Acute lung injury (ALI) frequently occurs in infants after cardiopulmonary bypass (CPB) surgery and it sometimes develops into acute respiratory distress syndrome in critically ill infants, which can be life threatening. This study investigated the effects of open lung ventilation on the haemodynamics and respiratory mechanics of 64 infants (34 males; 30 females) with a mean ± SD age of 8.3 ± 0.3 months who developed ALI following CPB surgery. Open lung ventilation significantly improved the respiratory mechanics and oxygenation parameters of the infants, including the partial pressure of oxygen in arterial blood (PaO2), the ratio of PaO2/FiO2 (fraction of inspired oxygen), peak inspiratory pressure, static compliance and airway resistance. It is concluded that open lung ventilation can greatly improve oxygenation and respiratory mechanics in infants with ALI following CPB surgery.

Differentiation block of oligodendroglial progenitor cells as a cause for remyelination failure in chronic multiple sclerosis

Impaired function/differentiation of progenitor cells might provide an explanation for the limited remyelination observed in the majority of chronic multiple sclerosis lesions. Here, we establish that in the normal adult human CNS, the transcription factors Nkx2.2 and Olig2 are strongly expressed in progenitor cells while mature oligodendrocytes are characterized by low levels of Olig2 or Nkx2.2. In vitro studies confirmed the expression of Olig2 in oligodendroglial progenitor cells and mature oligodendrocytes while astrocytes, microglial cells and neurons were negative for Olig2. In early multiple sclerosis lesions, we found Olig2-positive progenitor cells throughout all lesion stages and in periplaque white matter (PPWM). The number of progenitors in PPWM was significantly increased compared with the white matter from controls. In chronic multiple sclerosis lesions progenitor cells were still present, however, in significantly lower numbers than in early multiple sclerosis lesions. A subpopulation of progenitor cells in early multiple sclerosis lesions and PPWM but not in control cases co-expressed NogoA, a marker of mature oligodendrocytes. The co-expression of these two markers suggested that these cells were maturing oligodendrocytes recently recruited from the progenitor pool. In contrast, in chronic multiple sclerosis lesions maturing progenitors were only rarely present. In summary, we provide evidence that a differentiation block of oligodendroglial progenitors is a major determinant of remyelination failure in chronic multiple sclerosis lesions.

Possible role of hydrogen sulfide on the preservation of donor rat hearts

OBJECTIVE

The aim of this study was to observe the preservative effect of hydrogen sulfide (H2S) on donor rat hearts.

MATERIALS AND METHODS

The hearts of 24 Sprague-Dawley rats were perfused on a Langendorff perfusion column for 30 minutes. We calculated and recorded the left ventricular-developed pressure (LVDP), and positive and negative derivatives of left ventricular systolic pressure (LVSP; +dP/dt and -dP/dt). Hearts were then arrested and stored for 6 hours at 4 degrees C: group 1, Krebs-Henseleit (KH) solution; group 2, KH solution with 1 micromol/L NaHS; group 3, KH solution with 1 micromol/L NaHS and 10 micromol/L glibenclamide; group 4, St. Thomas II solution. Hearts were transferred back to the Langendorff column. After stabilizing for 30 minutes, LV performance was assessed as before. The donor hearts were kept for pathological study including myocardial water ratio, ATP content, and myocyte apoptosis index.

RESULTS

The recovery rates of +dp/dtmax, -dp/dtmax, and LVDP of groups 2 and 4 were much better than those of groups 1 and 3. The hearts contracted immediately after reperfusion in group 4. Ventricular fibrillation was seen before contraction in the other 3 groups, with the longest duration in group. No significant difference in myocardial water ratio was found. The ATP content was the highest in group 2. Apoptosis was observed in the 4 groups with the lowest apoptosis index in group 2.

CONCLUSIONS

H2S has a protective effect on rat donor hearts at the concentration of 1 micromol/L. The protective effect is better than that of St. Thomas II solution. The protective effect of H2S can be blocked by glibenclamide.

Differential roles of phosphatidylinositol 3-kinase/akt pathway in retinal ganglion cell survival in rats with or without acute ocular hypertension

Intraocular pressure (IOP) elevation has often been used as an experimental model to study mechanisms underlying retinal ganglion cell (RGC) death associated with ocular ischemic injury and glaucoma. The aim of the present study, using both in vitro and in vivo approaches, was to investigate the role of phosphatidylinositol 3-kinase (PI3K)/akt pathway in RGC viability in normal rats and rats following transient IOP elevation. For in vivo studies, pathway inhibitors were administered intravitreally on days 3, 9, and 15 post-2-h IOP elevation at 110 mm Hg. Toward the end of the 3-week examination period, the fluorescent dye Fluorogold was used to retrogradely label surviving RGCs. In order to examine the role of macrophages that were recruited into the eye following the pathway inhibition, clodronate liposomes were used to deplete phagocytic cells in the eye. PI3K/akt pathway activity and location in the retina were examined using Western blot and immunohistochemistry, respectively. Here we showed that PI3K/akt inhibitors 2-(4-morpholinyl)-8-phenyl-1(4H)-benzopyran-4-one hydrochloride (LY294002) and KY12420 at low concentrations (2 microM or 20 microM) did not influence RGC survival but caused RGC loss at high concentration (200 muM) in retinal explants derived from intact rats. In contrast, both LY294002 and KY12420 at 20 microM led to RGC loss in retinal explants derived from IOP-elevated eyes. A detrimental action of phagocytic cells on RGC survival was also seen in these retinas. In vivo results confirmed the detrimental actions of PI3K/akt inhibition and macrophages on RGC survival in IOP-elevated, but not intact eyes even with high concentration of LY294002. Low level of PI3K/akt activity was detected in the ganglion cell layer (GCL) in intact retina. Acute IOP elevation activated PI3K/akt pathway in the inner nuclear layer and GCL including RGCs. This study thus demonstrates that PI3K/akt pathway mediates RGC survival after IOP elevation but not under normal condition.

Regulatory network motifs and hotspots of cancer genes in a mammalian cellular signalling network

Mutations or overexpression of signalling genes can result in cancer development and metastasis. In this study, we manually assembled a human cellular signalling network and developed a robust bioinformatics strategy for extracting cancer-associated single nucleotide polymorphisms (SNPs) using expressed sequence tags (ESTs). We then investigated the relationships of cancer-associated genes [cancer-associated SNP genes, known as cancer genes (CG) and cell mobility genes (CMGs)] in a signalling network context. Through a graph-theory-based analysis, we found that CGs are significantly enriched in network hub proteins and cancer-associated genes are significantly enriched or depleted in some particular network motif types. Furthermore, we identified a substantial number of hotspots, the three- and four-node network motifs in which all nodes are either CGs or CMGs. More importantly, we uncovered that CGs are enriched in the convergent target nodes of most network motifs, although CMGs are enriched in the source nodes of most motifs. These results have implications for the foundations of the regulatory mechanisms of cancer development and metastasis.

A critical evaluation of different QM/MM frontier treatments with SCC-DFTB as the QM method

The performance of different link atom based frontier treatments in QM/MM simulations was evaluated critically with SCC-DFTB as the QM method. In addition to the analysis of gas-phase molecules as in previous studies, an important element of the present work is that chemical reactions in realistic enzyme systems were also examined. The schemes tested include all options available in the program CHARMM for SCC-DFTB/MM simulation, which treat electrostatic interactions due to the MM atoms close to the QM/MM boundary in different ways. In addition, a new approach, the divided frontier charge (DIV), has been implemented in which the partial charge associated with the frontier MM atom ("link host") is evenly distributed to the other MM atoms in the same group. The performance of these schemes was evaluated based on properties including proton affinities, deprotonation energies, dipole moments, and energetics of proton transfer reactions. Similar to previous work, it was found that calculated proton affinities and deprotonation energies of alcohols, carbonic acids, amino acids, and model DNA bases are very sensitive to the link atom scheme; the commonly used single link atom approach often gives error on the order of 15 to 20 kcal/mol. Other schemes give better and, on average, mutually comparable results. For proton transfer reactions, encouragingly, both activation barriers and reaction energies are fairly insensitive (within a typical range of 2-4 kcal/mol) to the link atom scheme due to error cancellation, and this was observed for both gas-phase and enzyme systems. Therefore, the effect of using different link atom schemes in QM/MM simulations is rather small for chemical reactions that conserve the total charge. Although the current study used an approximate DFT method as the QM level, the observed trends are expected to be applicable to QM/MM methods with use of other QM approaches. This observation does not mean to encourage QM/MM simulations without careful benchmark in the study of specific systems, rather it emphasizes that other technical details, such as the treatment of long-range electrostatics, tend to play a more important role and need to be handled carefully.

Strain-specific differences in the effects of cyclosporin A and FK506 on the survival and regeneration of axotomized retinal ganglion cells in adult rats

The immune response can influence neuronal viability and plasticity after injury, effects differing in strains of rats with different susceptibility to autoimmune disease. We assessed the effects of i.p. injections of cyclosporin A (CsA) or FK506 on adult retinal ganglion cell (RGC) survival and axonal regeneration into peripheral nerve (PN) autografted onto the cut optic nerve of rats resistant (Fischer F344) or vulnerable (Lewis) to autoimmune disease. Circulating and tissue CsA and FK506 levels were similar in both strains. Three weeks after autologous PN transplantation the number of viable beta-III tubulin-positive RGCs was significantly greater in CsA- and FK506-treated F344 rats compared with saline-injected controls. RGC survival in Lewis rats was not significantly altered. In F344 rats, retrograde labeling of RGCs revealed that CsA or FK506 treatment significantly increased the number of RGCs that regenerated an axon into a PN autograft; however these agents had no beneficial effect on axonal regeneration in Lewis rats. PN grafts in F344 rats also contained comparatively more pan-neurofilament immunoreactive axons. In both strains, 3 weeks after transplantation CsA or FK506 treatment resulted in increased retinal macrophage numbers, but only in F344 rats was this increase significant. At this time-point PN grafts in both strains contained many macrophages and some T cells. T cell numbers in Lewis rats were significantly greater than in F344 animals. The increased RGC axonal regeneration seen in CsA- or FK506-treated F344 but not Lewis rats shows that modulation of immune responses after neurotrauma has complex and not always predictable outcomes.

Administration of donor-derived mesenchymal stem cells can prolong the survival of rat cardiac allograft

BACKGROUND

Mesenchymal stem cells (MSCs) are multipotent adult elements that have recently been shown to have profound immunomodulatory effects both in vitro and in vivo. Herein we have examined the impact of intravenous infusion of donor MSCs on the survival of transplanted hearts in a rat allograft model.

METHODS

Recipient Fisher344 rats were transplanted with hearts from inbred Wistar rats. Wistar rat MSCs were infused via the tail vein at designated intervals. In vitro mixed lymphocyte reaction (MLR) and cell-mediated lympholysis (CML) assays were performed to assess whether MSCs downregulated T-cell responses in vivo. Real-time polymerase chain reaction (PCR) was used to analyze the Th1/Th2 balance in MSC-treated and control groups.

RESULTS

The MSCs cultured in vitro exhibited multipotential for differentiation. Survival of the allografts was markedly prolonged by administration of MSCs compared with the controls, namely mean survivals of 12.4 vs 6.4 days, respectively. Real-time PCR showed a shift in the Th1/Th2 balance toward Th2. By MLR and CML assays, untreated control rats showed greater alloreactivity than did MSC-treated rats.

CONCLUSION

Our results indicated that MSCs suppressed allogeneic T-cell responses both in vitro and in vivo. Intravenous administration of MSCs prolonged the survival of transplanted hearts, possibly by induction of allograft tolerance through changing the Th1/Th2 balance.

Dynamics of X+CH4 (X=H,O,Cl) reactions: How reliable is transition state theory for fine-tuning potential energy surfaces?

Trajectory calculations run on global potential energy surfaces have shown that the topology of the entrance channel has strong implications on the dynamics of the title reactions. This may explain why huge differences are observed between the rate constants calculated from global dynamical methods and those obtained from local methods that employ the same potential energy surfaces but ignore such topological details. Local dynamics approaches such as transition state-based theories should then be used with caution for fine-tuning potential energy surfaces, especially for fast reactions with polyatomic species since the key statistical assumptions of the theory may not be valid for all degrees of freedom.

AAV-mediated expression of CNTF promotes long-term survival and regeneration of adult rat retinal ganglion cells

We compared the effects of intravitreal injection of bi-cistronic adeno-associated viral (AAV-2) vectors encoding enhanced green fluorescent protein (GFP) and either ciliary neurotrophic factor (CNTF), brain-derived neurotrophic factor (BDNF) or growth-associated protein-43 (GAP43) on adult retinal ganglion cell (RGC) survival and regeneration following (i) optic nerve (ON) crush or (ii) after ON cut and attachment of a peripheral nerve (PN). At 7 weeks after ON crush, quantification of betaIII-tubulin immunostaining revealed that, compared to AAV-GFP controls, RGC survival was not enhanced by AAV-GAP43-GFP but was increased in AAV-CNTF-GFP (mean RGCs/retina: 17 450+/-358 s.e.m.) and AAV-BDNF-GFP injected eyes (10 200+/-4064 RGCs/retina). Consistent with increased RGC viability in AAV-CNTF-GFP and AAV-BDNF-GFP injected eyes, these animals possessed many betaIII-tubulin- and GFP-positive fibres proximal to the ON crush. However, only in the AAV-CNTF-GFP group were regenerating RGC axons seen in distal ON (1135+/-367 axons/nerve, 0.5 mm post-crush), some reaching the optic chiasm. RGCs were immunoreactive for CNTF and quantitative RT-PCR revealed a substantial increase in CNTF mRNA expression in retinas transduced with AAV-CNTF-GFP. The combination of AAV-CNTF-GFP transduction of RGCs with autologous PN-ON transplantation resulted in even greater RGC survival and regeneration. At 7 weeks after PN transplantation there were 27 954 (+/-2833) surviving RGCs/retina, about 25% of the adult RGC population. Of these, 13 352 (+/-1868) RGCs/retina were retrogradely labelled after fluorogold injections into PN grafts. In summary, AAV-mediated expression of CNTF promotes long-term survival and regeneration of injured adult RGCs, effects that are substantially enhanced by combining gene and cell-based therapies/interventions.

Application of I125 Brachytherapy Combined Artificial Joint Prosthesis in Malignant Osteo- and Soft-Tissue Sarcoma

OBJECTIVES

The aim of this study was to evaluate the brachytherapy effectiveness of I(125) seeds combined with artificial prosthesis in malignant sarcoma therapy.

METHODS

The combination of I(125) seeds and artificial prosthesis was implanted to replace tumor section for three clinical cases-2 malignant osteosarcoma patients and 1 malignant soft-tissue tumor patient- through the direct operation.

RESULTS

Approximately 14-18 months after the operation, the results of our post-operational investigation showed that the tumor tissues of 3 patients had been completely removed. The limb functions recovered well. The brachytherapy of the combination of I(125) seeds and artificial prosthesis in malignant tumor improved the curative effect. No tumor existed, and no infection occurred.

CONCLUSIONS

It was demonstrated that this method was safe and easy. No side-effect was observed after the implantation of I(125) seeds. The brachytherapy was proven to be a potential method for patients who were at high risk to recrudesce the malignant osteosarcoma of tumors after the tumor excision.

SEA0400, a novel Na+/Ca2+ exchanger inhibitor, reduces calcium overload induced by ischemia and reperfusion in mouse ventricular myocytes

Given the potential clinical benefit of inhibiting Na+/Ca2+ exchanger (NCX) activity during myocardial ischemia reperfusion (I/R), pharmacological approaches have been pursued to both inhibit and clarify the importance of this exchanger. SEA0400 was reported to have a potent NCX selectivity. Thus, we examined the effect of SEA0400 on NCX currents and I/R induced intracellular Ca2+ overload in mouse ventricular myocytes using patch clamp techniques and fluorescence measurements. Ischemia significantly inhibited inward and outward NCX current (from -0.04+/-0.01 nA to 0 nA at -100 mV; from 0.23+/-0.08 nA to 0.11+/-0.03 nA at +50 mV, n=7), Subsequent reperfusion not only restored the current rapidly but enhanced the current amplitude obviously, especially the outward currents (from 0.23+/-0.08 nA to 0.49+/-0.12 nA at +50 mV, n=7). [Ca2+]i, expressed as the ratio of Fura-2 fluorescence intensity, increased to 138+/-7% (P<0.01) during ischemia and to 210+/-11% (P<0.01) after reperfusion. The change of NCX current and the increase of [Ca2+]i during I/R can be blocked by SEA0400 in a dose-dependent manner with an EC50 value of 31 nM and 28 nM for the inward and outward NCX current, respectively. The results suggested that SEA0400 is a potent NCX inhibitor, which can protect mouse cardiac myocytes from Ca2+ overload during I/R injuries.

Toward theoretical analysis of long-range proton transfer kinetics in biomolecular pumps

Motivated by the long-term goal of theoretically analyzing long-range proton transfer (PT) kinetics in biomolecular pumps, researchers made a number of technical developments in the framework of quantum mechanics-molecular mechanics (QM/MM) simulations. A set of collective reaction coordinates is proposed for characterizing the progress of long-range proton transfers; unlike previous suggestions, the new coordinates can describe PT along highly nonlinear three-dimensional pathways. Calculations using a realistic model of carbonic anhydrase demonstrated that adiabatic mapping using these collective coordinates gives reliable energetics and critical geometrical parameters as compared to minimum energy path calculations, which suggests that the new coordinates can be effectively used as reaction coordinate in potential of mean force calculations for long-range PT in complex systems. In addition, the generalized solvent boundary potential was implemented in the QM/MM framework for rectangular geometries, which is useful for studying reactions in membrane systems. The resulting protocol was found to produce water structure in the interior of aquaporin consistent with previous studies including a much larger number of explicit solvent and lipid molecules. The effect of electrostatics for PT through a membrane protein was also illustrated with a simple model channel embedded in different dielectric continuum environments. The encouraging results observed so far suggest that robust theoretical analysis of long-range PT kinetics in biomolecular pumps can soon be realized in a QM/MM framework.

cAMP regulates axon outgrowth and guidance during optic nerve regeneration in goldfish

Increased cAMP improves neuronal survival and axon regeneration in mammals. Here, we assess cAMP levels and identify activated pathways in a spontaneously regenerating central nervous system. Following optic nerve crush in goldfish, almost all retinal ganglion cells (RGC) survive and regenerate retinotectal topography. Goldfish received injections of a cAMP analogue (CPT-cAMP), a protein kinase A (PKA) inhibitor (KT5720), both compounds combined, or PBS (control). RGC survival in experimental groups was unaffected at any stage. The rate of axon regeneration was accelerated by the activator and decelerated both by the inhibitor and by combined injections, suggesting a PKA-dependent pathway. In addition, errors in regenerate retinotectal topography were observed when agents were applied in vivo and RGC response to the guidance cue ephrin-A5 in vitro was altered by the inhibitor. Our results highlight that therapeutic manipulation of cAMP levels to enhance axonal regeneration in mammals must ensure that topography, and consequently function, is not disrupted.

Retinal ganglion cell neurotrophin receptor levels and trophic requirements following target ablation in the neonatal rat

Superior colliculus (SC) ablation in neonatal rats results in a rapid increase in retinal ganglion cell (RGC) death. This injury-induced death is reduced by exogenous brain-derived neurotrophic factor or neurotrophin-4/5 (NT-4/5), but the protective effect of these molecules is transient, delaying but not preventing neuronal loss. We sought to discover why neurotrophins only temporarily reduce RGC death after target ablation, focusing on changes in neurotrophin receptor expression and possible changes in growth factor dependency. In unlesioned rats, receptor tyrosine kinase B (trkB) immunohistochemistry revealed no change in the number of trkB positive cells in the RGC layer 24 h after intraocular NT-4/5 injection. However, after SC lesions there were significantly less immunoreactive cells and, surprisingly, even fewer immunoreactive cells in NT-4/5 injected eyes. Semi-quantitative confocal analysis of immunofluorescence intensity revealed an increase in trkB staining in the RGC layer in unlesioned rats 24 h after NT-4/5 injection, whereas in SC-lesioned animals exposed to NT-4/5 there was a significant decrease in staining. To determine whether injured neonatal RGCs can switch their trophic requirements, different doses of ciliary neurotrophic factor were given intraocularly, either alone or combined with NT-4/5. We also tested an SC-derived chondroitin sulfate proteoglycan that has been reported to promote neonatal RGC survival. None of these interventions reduced lesion-induced RGC death 24 or 36 h after SC ablation. In summary, we show that developing RGCs do not shift their trophic dependence to other survival factors following injury; rather, the application of neurotrophins causes a down-regulation of the cognate trkB receptor, presumably altering the long-term responsiveness of neonatal RGCs to exogenous neurotrophins. These data highlight the difficulty in promoting long-term neuronal survival when using one-off administration of recombinant growth factors.

Uterine adenomyoma with lymphoid infiltration simulating lymphoma

BACKGROUND

Uterine leiomyoma with lymphoid infiltration is a rare disease that simulates malignant lymphoma with only nine cases reported to date. We describe the first case of uterine adenomyoma with lymphoid infiltration simulating lymphoma.

CASE

The specimen resected from a 30-year-old Chinese woman was a well-defined firm nodule measuring 5 x 5.5 x 5.5 cm. The cut surface was similar to that of adenomyoma, which contained dark brown spots and a cyst. Microscopically, the tumor comprised smooth muscle cells intermixed with many lymphocytes. Many lymphoid follicles were present, just locating beside one side of thin-walled blood vessels and protruding into the vessels. Endometrial-type glands and stroma were visible in the tumor.

CONCLUSION

We describe the first case of uterine adenomyoma with lymphoid infiltration simulating lymphoma.

The missing link between thermodynamics and structure in F1-ATPase

F(1)F(o)-ATP synthase is the enzyme responsible for most of the ATP synthesis in living systems. The catalytic domain F(1) of the F(1)F(o) complex, F(1)-ATPase, has the ability to hydrolyze ATP. A fundamental problem in the development of a detailed mechanism for this enzyme is that it has not been possible to determine experimentally the relation between the ligand binding affinities measured in solution and the different conformations of the catalytic beta subunits (beta(TP), beta(DP), beta(E)) observed in the crystal structures of the mitochondrial enzyme, MF(1). Using free energy difference simulations for the hydrolysis reaction ATP+H(2)O --> ADP+P(i) in the beta(TP) and beta(DP) sites and unisite hydrolysis data, we are able to identify beta(TP) as the "tight" (K(D) = 10(-12) M, MF(1)) binding site for ATP and beta(DP) as the "loose" site. An energy decomposition analysis demonstrates how certain residues, some of which have been shown to be important in catalysis, modulate the free energy of the hydrolysis reaction in the beta(TP) and beta(DP) sites, even though their structures are very similar. Combined with the recently published simulations of the rotation cycle of F(1)-ATPase, the present results make possible a consistent description of the binding change mechanism of F(1)-ATPase at an atomic level of detail.

[Evaluation of myometrial invasion in endometrial carcinoma]

OBJECTIVE

To determine the value of preoperative ultrasound, intraoperative gross visual inspection and postoperative bulk specimen measurement in evaluating the diagnosis of myometrial invasion in endometrial carcinoma.

METHODS

A total of 133 cases of women with endometrial carcinoma were analyzed focusing on evaluating the diagnosis of myometrial invasion by preoperative ultrasound, intraoperative gross visual inspection and postoperative bulk specimen measurement. The relationship between CA(125) and endometrial carcinoma of 91 cases of endometrial carcinoma was also analyzed.

RESULTS

In the diagnosis of myometrial invasion and deep myometrial invasion, ultrasound showed a sensitivity of 62.6% and 47.8% and a specificity of 67.7% and 90.0%, respectively, and intraoperative gross visual inspection showed a sensitivity of 59.6% and 73.9% and a specificity of 76.5% and 94.6%, respectively. The sensitivity of postoperative bulk specimen measurement was 70.0% and 94.4% and the specificity was 92.0% and 97.7%, respectively. The levels of CA(125) had no correlation with depth of myometrial invasion in endometrial carcinoma, but they had correlation with International Federation of Gynecology and Obstetrics (FIGO) stage.

CONCLUSIONS

Preoperative ultrasound, intraoperative gross visual inspection and postoperative bulk specimen measurement were helpful to the diagnosis of depth of myometrial invasion in endometrial carcinoma, and postoperative bulk specimen measurement seems to be better. CA(125) could not evaluate depth of myometrial invasion in endometrial carcinoma.

[Retrospective analysis of seven cases of pulmonary cryptococcosis]

OBJECTIVE

To understand the diagnosis and treatment of pulmonary cryptococcosis.

METHODS

Patients diagnosed as having pulmonary cryptococcosis in the past 15 years were retrospectively studied. Their demographic data, respiratory symptoms, diagnostic methods, chest radiograph, immune state, antifungal therapy and follow-up results were analyzed.

RESULTS

Thirty cases of cryptococcosis were diagnosed, of which 7 were diagnosed as having pulmonary cryptococcosis, one of them presented with concomitant meningitis. Of the 7 patients, 4 were male and 3 were female, with a median age of 41.8. All were HIV negative; one case was immunocompromised with a history of colon cancer and glucocorticoid therapy for 8 months, while others were immunocompetent. Three patients complained of low fever or cough and sputum, while 4 others presented no symptoms. The X-ray and chest CT showed unilateral or bilateral patches, nodules or cavities. The diagnosis was made by pathology and bacterial culture of sputum or bronchoalveolar lavage fluid. Amphotericin B plus flucytosine were initially given to 4 patients, all of them developed liver and renal abnormalities to some degree after therapy. Three patients were given fluconazole or itraconazole initially. All the 7 patients with pulmonary cryptococcosis responded favorably to antifungal therapy and the prognosis was good.

CONCLUSIONS

Clinically pulmonary cryptococcosis was less common than cryptococcal meningitis. Pathology and cryptococcal culture were essential to the diagnosis. For immunocompetent patients with pulmonary cryptococcosis, the prognosis was good.

Clinical analysis of 4 cases of juvenile granulosa cell tumor of the ovary

OBJECTIVE

To review the diagnosis, treatment and prognosis of juvenile granulosa cell tumor of the ovary (JGCT).

METHODS

To review four patients with JGCT treated in Peking Union Medical College Hospital from 1983 to 2002.

RESULTS

JGCT is rare and most of the patients are adolescent or children. Solid pelvic mass with ascites and pleural effusion were mainly clinical feature. The levels of estrogen of the four patients were normal. Diagnoses were made by pathology. All 4 patients were at stage I and treated with surgery and combined chemotherapy. Two patients with high mitotic index progressed and died after 10 and 14 months, and the others without high mitotic index obtained a complete remission for 25 and 32 months.

CONCLUSIONS

The diagnosis of JGCT is made by pathology definitely. The prognosis is poor when patient has high mitotic index. Cytoreductive surgery is the treatment of choice and combination chemotherapy may be helpful to improve the prognosis of JGCT.

Comparison of lumbar spine fusion using mixed and cloned marrow cells

STUDY DESIGN

Prospective study on lumbar spine fusion using cloned and mixed marrow cells.

OBJECTIVE

To analyze the effectiveness of cloned osteoprogenitor cells in spine fusion and their differentiation in vivo using a traceable gene.

SUMMARY OF BACKGROUND DATA

Although autografts are currently the standard for stable spine fusion, supply is limited. Alternative graft materials need to be developed and evaluated.

METHODS

An osteoprogenitor cell, D1-BAG, cloned from mouse bone marrow and transduced with LacZ and neomycin resistance genes, and mixed marrow stromal cells from marrow blowouts were used in athymic rats to establish posterior spinal fusion; 2 x 10(6) cells in 100 microL Matrigel were implanted into the lumbar fusion bed in 36 animals, whereas Matrigel without cells was used in 16 animals as control. Rats were killed at 2, 3, 6, and 9 weeks, and the spines were evaluated by manual palpation, radiographs, and histology.

RESULTS

Two weeks after surgery radiopaque tissue was seen at transplantation sites with D1-BAG cells but not at sites with mixed marrow stromal cells. Successful spine fusion at 6 and 9 weeks was observed in 8 of 8 (100%) animals receiving DI-BAG cells, 4 of 8 (50%) in mixed marrow stromal cells, and 0 of 8 (0%) in control animals.

CONCLUSIONS

Compared with mixed marrow stromal cells, cloned osteoprogenitor cells can produce a larger amount of mature osseous tissue at an earlier time point during spine fusion.

Substrate conformational transitions in the active site of chorismate mutase: their role in the catalytic mechanism

Chorismate mutase acts at the first branch-point of aromatic amino acid biosynthesis and catalyzes the conversion of chorismate to prephenate. The results of molecular dynamics simulations of the substrate in solution and in the active site of chorismate mutase are reported. Two nonreactive conformers of chorismate are found to be more stable than the reactive pseudodiaxial chair conformer in solution. It is shown by QM/MM molecular dynamics simulations, which take into account the motions of the enzyme, that when these inactive conformers are bound to the active site, they are rapidly converted to the reactive chair conformer. This result suggests that one contribution of the enzyme is to bind the more prevalent nonreactive conformers and transform them into the active form in a step before the chemical reaction. The motion of the reactive chair conformer in the active site calculated by using the QM/MM potential generates transient structures that are closer to the transition state than is the stable CHAIR conformer.

[Alterations in DPC4 gene in pancreatic cancers]

OBJECTIVE

To examine the alterations in the DPC4 gene in pancreatic cancers.

METHODS

Five pancreatic adenocarcinoma cell lines (P1, P2, P3, P4, and P7) and 11 fresh frozen pancreatic cancer tissues were monitored with polymerase chain reaction (PCR), single-strand conformation polymorphism (SSCP) analysis to demonstrate the sequence of deletion and mutation in 6 exons (1, 2, 3, 4, 8, and 11) of the DPC4 gene.

RESULTS

Mutation in the DPC4 gene was found in 3 of 5 cells lines (P1, P2, and P3). Three of eleven fresh-frozen tissues showed homozygous deletions and two showed intragenic mutations, with a gene alteration frequency of 45.5% (5/11).

CONCLUSION

Alterations in tumor-suppressor gene DPC4 may play an important role during the tumorigenesis of pancreatic cancer.

Triosephosphate isomerase: a theoretical comparison of alternative pathways

Three mechanisms proposed for the triosephosphate isomerase (TIM) catalyzed reactions were studied with the QM/MM approach using B3LYP/6-31+G(d,p) as the QM method. The two pathways that involve an enediol species were found to give similar values for the barriers and the calculated rates are in satisfactory agreement with experiment. By contrast, the mechanism that involves intramolecular proton transfer in the enediolate was found to be energetically unfavorable due to electrostatic interactions with His 95, a conserved residue in TIM from different organisms. A perturbation analysis was used to determine the residues that make the major contribution to catalysis.

Activity of the botanical aphicides 1,5-diphenyl-1-pentanone and 1,5-diphenyl-2-penten-1-one on two species of Aphididnae

1,5-Diphenyl-1-pentanone (A) and 1,5-diphenyl-2-penten-1-one (B) are natural products extracted for the first time from Stellera chamaejasme. Laboratory bioassay showed that the two products have strong contact activity and very good anti-feedant activity against Aphis gossypii and Schizaphis graminum. Both products showed dose-dependent relationships for both forms of activity against the two aphids, the contact activity of B being about twice that of A. Both products were inferior to methomyl in contact activity but superior in anti-feedant activity against the two aphids. This is the first report of aphicidal activity in these two compounds, which may represent a new class of aphicide.

CNTF promotes the regrowth of retinal ganglion cell axons into murine peripheral nerve grafts

Autologous peripheral nerves were transplanted onto transected optic nerves of adult mice. We examined whether intraocular CNTF injections increased retinal ganglion cell (RGC) axon regeneration, and what types of RGCs regrew axons into grafts. After temporal CNTF eye injections there were more fluorogold-labelled regenerating RGCs (mean +/- s.e.m. 342+/-113.1; n=6) than in sham eye-injected mice (133+/-27.6; n=8). Greater numbers of regenerating RGCs (1198+/-367.6; n=6) were seen in mice receiving both nasal and temporal CNTF injections. The range of soma areas in regenerate and normal retinas was similar but the average size of regenerating RGCs was greater (212 microm2 vs 111 microm2). Most regenerating RGCs had large dendritic fields. The data suggest a heterogeneous response to axotomy in adult mice, large RGCs preferentially regrowing axons into PN grafts.

[Expression of epidermal growth factor receptor in gestational trophoblastic tumours]

OBJECTIVE

To investigate the expression of epidermal growth factor receptor (EGFR) in gestational trophoblastic tumours and its clinical significance.

METHODS

Placentas of 10 normal early pregnancies, 20 molar pregnancies, 10 samples from invasive mole and 8 samples of choriocarcinoma were used for the study. EGFR expression was evaluated by immunohistochemistry using monoclonal antibody.

RESULTS

EGFR was expressed both in normal chorionic villi and tissues of trophoblastic tumours. EGFR was expressed more strongly in normal chorionic villi and non-malignant transformed hydatidiform mole than in malignant transformed molar pregnancies and malignant trophoblastic tumours (P < 0.05). Univariate and multivariate analysis indicated that EGFR immunostaining intensity was significantly related to the clinical stage in malignant trophoblastic tumours (P = 0.026, OR = 9.874).

CONCLUSION

EGFR expression could be used as an index for prediction of malignant transformation of hydatidiform mole and staging of malignant trophoblastic tumours.

NT-4/5 reduces cell death in inner nuclear as well as ganglion cell layers in neonatal rat retina

Using the TUNEL method, we examined the effect of intraocular NT-4/5 injections on cell death in ganglion and non-ganglion cell layers in 5-day-old rat retinas. NT-4/5 reduced the level of naturally occurring cell death in all retinal layers. Twenty-four hours after superior colliculus (SC) lesions there was a significant increase in the density of TUNEL+ profiles in the RGC layer (6.43/mm2 in normal vs (8.89/mm2 after lesions) which was ameliorated by intraocular NT-4/5 injections (8.79/mm2). Surprisingly, after SC ablation a significant increase in TUNEL+ profiles was also seen in non-ganglion cell layers (52.25/mm2 in normal vs 89.35/mm2 after lesions), mostly in the developing inner nuclear layer. Death in non-ganglion cell layers was also significantly reduced (43.09/mm2) after NT-4/5 eye injections.

[Primary non-specific ureteritis]

OBJECTIVE

To better understand primary non-specific ureteritis.

METHODS

The etiological, clinical, and pathological manifestations, diagnosis, and treatment of 3 cases of primary non-specific ureteritis were discussed.

RESULTS

Preoperative diagnosis failed. Uretero-ureterostomy was performed in 2 cases, and ureteroneocystostomy in one. The patients were free from hydronephrosis and ureteral dilatation.

CONCLUSIONS

Diagnosis depends on pathological manifestations, differentiation from secondary non-specific ureteritis, ureteral tuberculosis, negative X-ray of ureteral stone and ureteral carcinoma. Surgical intervention is effective with good prognosis.

Pluripotential mesenchymal cells repopulate bone marrow and retain osteogenic properties

Precursor cells, isolated from bone marrow, can develop into various cell types and may contribute to skeletal growth, remodeling, and repair. The D1 cell line was cloned from a multipotent mouse bone marrow stromal precursor and has osteogenic, chondrogenic, and adipogenic properties. The osteogenic phenotype of these precursor cells is relevant to the process of fracture healing and osteointegration of prosthetic implants. The D1 cells were labeled genetically using a replication incompetent retroviral vector encoding beta-galactosidase, an enzyme which is used as a marker. Labeled cells are readily identifiable by staining with 5-bromo-4-chloro-3-indoyl-beta-D-galactoside and by flow cytometry, and retain the desired osteogenic characteristics in vivo as shown by von Kossa staining, alkaline phosphatase assay, an increase in cyclic adenosine monophosphate in response to parathyroid hormone, osteocalcin messenger ribonucleic acid production, and bone formation in diffusion chambers. In addition, the cells cloned from marrow stroma repopulate the marrow of host mice, persist for several weeks, and retain their osteogenic potential ex vivo. The data suggest that such cells may be used to replenish the number of osteoprogenitors in marrow, which appear to decrease with age, thereby leading to recovery from bone loss and improved bone growth and repair. Labeling these cells creates a model in which to study the potential of such cells to participate in fracture repair, ingrowth around prosthetic implants, treatment of osteoporosis, and to explore the possibility of gene delivery to correct mutations or defects in metabolism that are responsible for certain skeletal abnormalities.

Pluripotential marrow cells produce adipocytes when transplanted into steroid-treated mice

The effect of steroids on adipogenesis by D1-BAG, a pluripotent cell cloned from mouse bone marrow and transfected with traceable genes encoding beta-galactosidase and neomycin resistance, was investigated in vitro in culture and in vivo after injection into mice. Treatment of D1-BAG cells in culture with dexamethasone produced an accumulation of lipid vesicles and stimulated expression of the fat cell-specific 422(aP2) mRNA. Fifty-six mice each received 1 x 10(6) D1-BAG cells, either by tail-vein injection or by direct injection into the marrow of the right femur. Another 38 mice received either saline injection or no treatment as controls. Half of the animals in each group were treated with 3 mg/kg of methylprednisolone per week. Analysis of marrow blow-outs by flow cytometry, DNA analysis by PCR, and X-gal stain of histological sections indicated that cells transplanted by either intravenous or intramedullary injection had appeared and persisted in the marrow of host mice. Cell sorting by flow cytometry and staining with Sudan IV demonstrated that steroid treatment produced adipogenesis in 5-9% of transplanted cells. The results indicate that steroid-induced differentiation of potentially osteogenic marrow cells into adipocytes in vivo may contribute to the development of osteoporosis and osteonecrosis.

[Detection of alterations of the DPC4 gene in paraffin-embedded tissues of pancreatic carcinomas]

OBJECTIVE

To examine the alteration and significance of the DPC4 gene in paraffin-embedded tissues of pancreatic carcinomas.

METHODS

Polymerase chain reaction and single-strand conformation polymorphism analysis were used to search for deletions and mutations in the DPC4 gene in 46 cases of pancreatic carcinomas.

RESULTS

Thirteen of forty-six (28.3%) cases were found to have homozygous deletions in exon 1, 2, 3, 4, 8 and 11. One was in exon 11, one in exon 1 and 11, one in exon 2 and 3, one in exon 3 and 8, one in exon 1, 2 and 8, one in exon 2, 4 and 11, one in exon 3, 4 and 11, three in exon 3, 4 and 8, one in exon 2, 3, 4, and 8, one in exon 2, 3, 8 and 11, one in exon 2, 3, 4, 8 and 11. Intragenic mutations were found in 10 of 46 cases (21.7%). One case was in exon 1, one in exon 2, three in exon 8, four in exon 11, and one in exon 4 and 11. The total frequency of intragenic changes of DPC4 in paraffin-embedded tissues was 45.6% (21/46).

CONCLUSION

Inactivation of tumor-suppressor gene DPC4 may play an important role during the tumorigenesis of pancreatic carcinomas.

[Cytosine diaminase/5-flurocytosine mediated inhibiting effect on the growth of human pancreatic carcinoma cells]

OBJECTIVE

To study the inhibition effect of E. coli cytosine diaminase (CD)/5-flurocytosine (5-FC) system on the growth of human pancreatic carcinoma cell line cells.

METHODS

Recombinant retroviral vector expressing CD genes was transduced into pancreatic carcinoma cell line cells. In vitro and in vivo prodrug sensitivity assays were carried out, including: (1) detection of growth and colony forming inhibition rate of transduced cells in the presence of 5-FC; (2) observation of bystander effect by MTT method; (3) observation of the growth inhibition effect of 5-FC on transduced cell xenografts in nude mice.

RESULTS

The growth and colony forming inhibition rate of the transduced cells in the presence of 5-FC were 80.0% and 79.0%, which were obviously higher than 4.8% and 5.0% (P < 0.01) of nontransduced cells. Mixed cells containing only 10% of transduced cells showed 50.7% reduction of proliferation (bystander effect). The growth of transduced cells xenografts could be totally regressed by 5-FC.

CONCLUSIONS

CD/5-FC system is a potential gene therapy strategy for pancreatic carcinoma.

[Different susceptibility of cell lines to thymidine kinase/ganciclovir-mediated killing effect and the way of cell death]

OBJECTIVE

To investigate the mechanism of variability of herpes simplex virus (HSV) thymidine kinase (TK)/ganciclovir (GCV)-mediated suicide effect obtained in three different cell lines and the ways in which this system-mediated cell killing occurs.

METHODS

Recombinant retroviral vector expressing HSV-TK was transduced into three cell lines known with different growth rate (PC-2, PC-7 and LLC-PK1). The doubling time of the transduced and parental cells was calculated. MTT method was used to detect the concentration of GCV at which cell growth was inhibited by 50% (IC(50) value). Cell cycle was analyzed by flow cytometry. Necrosis or apoptosis of cultured cells and/or xenografts was observed under light and electron microscope, and by in situ apoptosis detection.

RESULTS

The doubling time of the three parental cell lines was (31.2 +/- 0.1) h, (48.3 +/- 0.1) h, and (53.9 +/- 0.1) h, separately. The IC(50) values of their HSV-TK-transduced cell lines to GCV were (0.73 +/- 0.12) micromol/L, (0.93 +/- 0.16) micromol/L and (1.22 +/- 0.06) micromol/L, respectively and the IC(50) value was correlated with the cell doubling time. Flow cytometry revealed S arrest. The majority of cells under treatment of GCV displayed swelling and collapse, but very few cells showed apoptosis. Large areas of necrosis were observed in the xenografts.

CONCLUSIONS

The cells with high growth rate are more susceptible to HSV-TK/GCV-mediated killing effect. Necrosis is the main way in which cells of the three HSV-TK-transduced cells lines die.

The Nicolas Andry award. The pathogenesis and prevention of steroid-induced osteonecrosis

The effects of steroids on a cloned pluripotential cell from bone marrow stroma were examined in vitro in culture and in vivo after the cells were transfected with a traceable gene and transplanted into host mice. Bipedal chickens were treated with steroids to establish a model for osteonecrosis. The effects of a lipid lowering agent, lovastatin, on the prevention of steroid induced adipogenesis in vitro in cell culture, and on adipogenesis and osteonecrosis in vivo in chickens, were evaluated. On treatment with dexamethasone, cloned pluripotential cells began to differentiate into adipocytes and expressed a fat specific gene, whereas the expression of Type I collagen and osteocalcin messenger ribonucleic acid decreased. Addition of lovastatin in culture inhibited steroid induced fat gene expression and counteracted the inhibitory effect of steroids on osteoblastic gene expression. Cloned pluripotential cells were transduced with a traceable retrovirus vector encoding the beta-galactosidase and neomycin resistance genes. The transfected cells were administered to mice either by tail vein or by direct intramedullary injection. Half of the animals in each group were treated with steroids. Histologic sections showed the appearance of transplanted cells in the marrow. Analysis of marrow blowouts by flow cytometry revealed that steroid treatment produced adipogenesis in transplanted cells. Evidence of osteonecrosis was observed in steroid treated chickens, whereas sections from animals treated with steroids and lovastatin showed less adipogenesis and no bone death. The results indicate that steroid induced adipogenesis in the marrow may contribute to osteonecrosis and that lovastatin may be helpful in preventing the development of steroid induced osteonecrosis.

[The mechanism of bystander effect in herpes simplex virus thymidine kinase/ganciclovir-mediated gene therapy]

OBJECTIVE

To study the mechanism of bystander effect in herpes simplex virus thymidine kinase (HSV-TK)/Ganciclovir (GCV)-mediated gene therapy.

METHODS

Recombinant retroviral vectors expressing HSV-TK and beta-Galactosidase (Lac Z) genes were constructed and transferred into pancreatic carcinoma cell line respectively. Cell counting was used to detect the growth inhibition rate of HSV-TK-transduced cells in presence of GCV. Taking Lac Z-transduced cells as bystander cells, the bystander effect was detected by MTT method, and its mechanism was studied by the experiments of supernatant shifting, Verapamil inhibition and ultrastructural observation.

RESULTS

The growth inhibition rate of the HSV-TK-transduced cells in the presence of GCV was 92.1%, which was obviously 4.9% and 3.2% higher than of the non-and control vector-transduced cells. Mixed cells containing only 10% of HSV-TK-transduced cells showed 39.0% reduction of the proliferation, which meant there was an obvious bystander effect in the system. However this effect disappeared when transferring GCV-containing supernatant of HSV-TK-transduced cells to the parent cells and could be reduced significantly when verapamil was added in the medium, indicating that this bystander effect requires cell-cell contact. Gap junctions were observed existing between PC-2 cells by electron microscopy.

CONCLUSION

The bystander effect in HSV-TK/GCV-mediated gene therapy occurs by transfer of GCV metabolite from cell to cell through gap junction.

[Specific activity of the promoter containing Myc-Max response elements in c-myc-overexpressing cells]

OBJECTIVE

To investigate the specific activity of a hybrid promoter which is constructed by replacing the third domain of herpes simplex virus (HSV) thymidine kinase (TK) promoter with the Myc-Max response elements.

METHODS

Myc-Max response elements were ligated with a third domain-deleted HSV-TK promoter by cloning and subcloning PCR products. Then a luciferase-expressing plasmid, in which the luciferase gene was put under the control of hybrid promoter, was constructed and transfected transiently into the cell lines which had been demonstrated to be c-myc over- or low-expressing by Northern blot hybridization. The luciferase activities in these cells were detected.

RESULTS

In c-myc over-expressing cells, the hybrid promoter (Mpr) led to high levels of (81,966 +/- 43,238) relative light units (RLUs) in PC-2 cells and (70,563 +/- 22,435) RLUs in PC-7 cells, which were 78- and 150-fold higher than those coming from the third domain-deleted TK promoter (Epr), and also 6.9- and 1.7-fold higher than the activities controlled by TK promoter. However, Mpr showed a very low activity in c-myc low-expressing cells, in which the luciferase activity was (431 +/- 73) RLUs, similar to (601 +/- 141) RLUs produced by Epr.

CONCLUSION

The activity of hybrid promoter, which is composed of Myc-Max response elements and the third domain-deleted TK promoter, possesses cell-type specificity for c-myc-overexpressing cells.

[The establishment of a human pancreatic mixed ductal-endocrine carcinoma cell line]

OBJECTIVE

Establishment of a human pancreatic mixed ductal-endocrine carcinoma cell line.

METHODS

A specimen of this type of cancer was obtained from a male patient at the head of pancreas. The tumor tissue was minced into pieces and inoculated subcutaneously in nude mice. With two successive subcutaneous implants, a piece of tumor tissue taken from the 2(nd) implanted neoplasm of a nude mouse was minced into minute tissue masses and inoculated in a media containing 10% fetal bovine serum.

RESULTS

Currently, it has been passed to the 55(th) passage. Cells of this cell line (PC-EN) kept simultaneously the morphologic patterns of a pancreatic ductal and endocrine tumor which were verified by histochemistry and immunohistochemistry assays. Some of the PC-EN cells showed presence of neuroendocrine granules by electron microscopy. The growth rate of this cell line was relatively low. Kakryotype analysis showed two cell populations with its major mode of chromosomes numbers as 48 in one, and 56 in the other. Study on K-ras gene demonstrated that PC-EN harbored a mutated codon 12. Several gastrointestinal hormones and CEA were detected in PC-EN cells and in the supra-cultured medium using radioimmunoassay.

CONCLUSIONS

The cellular and molecular biologic characteristics of PC-EN cells illustrated that this cell line preserved the morphology of a pancreatic ductal and endocrine tumor and possessed a special growth property, chromosome karyotype, and mutation of Ki-ras gene, but also showed a biologic exocrine and endocrine functions of the pancreas. The establishment of PC-EN cell line will provide a useful model in vitro for further investigating the cellular and molecular biology of exocrine and endocrine tumors of the pancreas.

Fatty marrow conversion of the proximal femoral metaphysis in osteonecrotic hips

To determine whether fatty marrow conversion of the proximal femoral metaphysis is related to osteonecrosis of the femoral head using a marrow conversion index ([signal intensity of the proximal femoral metaphysis/signal intensity of the greater trochanter] x 100 in T1 weighted magnetic resonance images), a case control study was conducted on 42 osteonecrotic hips in 28 patients. The 28 patients (42 osteonecrotic hips) were matched with 84 control patients (84 normal hips) for gender, age (5-year range), and time of presentation (1-year range). The marrow conversion index was measured in each hip studied. The index was 90.2% (standard deviation, 8.2%) in osteonecrotic hips and 75.1% (standard deviation, 9.1%) in matched controls. By conditional logistic regression, a 5% increase in the index was associated with 3.6 times increase of the odds ratio of osteonecrosis and a 10% increase with a 12.9 times increase of the odds ratio. The marrow conversion index, which reflects the ratio of fatty marrow conversion of the proximal femoral metaphysis to that of the greater trochanter measured on T1 weighted magnetic resonance images, is increased in osteonecrotic hips.