Achieving reuse of computable guideline systems

We describe an architecture for reusing computable guidelines and the programs used to interpret them across varied legacy clinical systems. Developed for the PRODIGY 3 project, our architecture aims to support interactive, point of care use of guidelines in primary care. Legacy medical record systems in UK primary care are diverse, using different terminologies, different data models, and varying user-interface philosophies. However, our goal is to provide common guideline knowledge bases and system components, while achieving full integration with the host medical record system, and a user interface tailored to that system. In conjunction with system suppliers, we identified areas of standardization required to achieve this goal. Firstly, standardized interfaces were created for mediation with the legacy system medical record and for act management. Secondly, a standard interface was developed for communication with the User Interface for guideline interaction. Thirdly, a terminology mapping knowledge base and system component was provided. Lastly, we developed a numeric unit conversion knowledge base and system component. The standardization of this architecture was achieved by close collaboration with existing vendors of Primary Care computing systems in the UK. The work has been verified by two suppliers successfully building and deploying systems with User Interfaces which mirror their normal look and feel, communicating fully with existing medical records, while using identical Guideline Interpreter components and knowledge bases. Encouragingly further experiments in other areas of clinical decision support have not required extension of our interfaces.

Sharable computer-based clinical practice guidelines: rationale, obstacles, approaches, and prospects

Clinical practice guideline automation at the point of care is of growing interest, yet most guidelines are authored in unstructured narrative form. Computer-based execution depends on a formal structured representation, and also faces a number of other challenges at all stages of the guideline lifecycle: modeling, authoring, dissemination, implementation, and update. This is because of the multiplicity of conceptual models, authoring tools, authoring approaches, intended applications, implementation platforms, and local interface requirements and operational constraints. Complexity and time required for development and structure are also huge obstacles. These factors argue for convergence on a common shared model for representation that can be the basis of dissemination. A common model would facilitate direct interpretation or mapping to multiple implementation environments. GLIF (GuideLine Interchange Format) is a formal representation model for guidelines, created by the InterMed Collaboratory as a proposed basis for a shared representation. GLIF currently addresses the process of authoring and dissemination; the InterMed team's major focus now is on tools to facilitate these tasks and the mapping to clinical information system environments. Because of limitations in what can be done by a single team with finite resources, however, and the variety of additional perspectives that need to be accommodated, the InterMed team has determined that further development of a shared representation would be best served as an open process in which the world community is engaged. Under the auspices of the HL7 Decision Support Technical Committee, a GLIF Special Interest Group has been established, which is intended to be a forum for collaborative refinement and extension of a standard representation that can support the needs of the guideline lifecycle. Significant areas for future work will need to include demonstrations of effective means for incorporating guide-lines at point of care, reconciliation of functional requirements of different models and identification of those most important for supporting practical implementation, im-proved means for authoring and management of complexity, and methods for automatically analyzing and validating syntax, semantics, and logical consistency of guidelines.

Neurotrophins, but not depolarization, regulate substance P expression in the developing optic tectum

Neurotransmitter expression can be regulated by both activity and neurotrophins in a number of in vitro systems. We examined whether either of these factors was likely to play a role in the in vivo optic nerve-dependent regulation of a substance P-like immunoreactive (SP-ir) population of cells in the developing optic tectum of the frog. In contrast to our previous results with the adult system, blocking tectal cell responses to glutamate release by retinal ganglion cells with 6-cyano-7-nitroquinoxaline-2,3 dione (CNQX) did not affect the percent of SP-ir cells in the developing tectum. Treatment with d-(-)-2-amino-5-phosphonovaleric acid (d-AP-5) was also ineffective in this regard, although both it and CNQX treatment disrupted visual map topography. Chronic treatment with brain-derived neurotrophic factor (BDNF) and neurotrophin-4/5 (NT-4/5) produced increases in SP-ir cells in the treated lobes of normal animals, which were significant in the case of NT-4/5. Both substances also prevented the decrease of SP cells that would otherwise occur in the deafferented lobe of unilaterally optic nerve-transected tadpoles. These changes in the percent of SP-ir cells occurred without any detectable changes in the overall number of tectal cells. NGF had no effect on SP expression. Nor did it affect topographic map formation, which was disrupted by treatment with either BDNF or NT-4/5. Our results demonstrate that different mechanisms regulate SP expression in the developing and adult tectum. They indicate that neurotrophin levels in the developing optic tectum may selectively regulate a specific neuropeptide-expressing population of cells.

[Clinic intervention study on urogenital mycoplasma infection of pregnant women]

OBJECTIVE

To explore the hypothesis of pathogenic relationship between urogenital mycoplasma infection and adverse perinatal outcomes.

METHODS

Four hundred and eighty-eight mycoplasma-positive pregnant women detected by culture method were randomly divided into erythromycine-intervention group and non-intervention group. Comparison was made on rate of reverse sero-conversion, of vertical transmission to mycoplasma and adverse perinatal outcomes incidence between groups.

RESULTS

Ureaplasma urealyticum sero-conversion rate and rate of vertical-transmission in intervention group were significantly lower than in non-intervention group (P < 0.05). The incidences rates of preturm labor, post partum fever, puerperal infection and neonate pneumonia in intervention group were significantly lower than in non-intervention group (P < 0.05).

CONCLUSION

Erythromycin is effective in control of ureaplasma urealyticum infection among pregnant women through cutting off vertical transmission passway and lowering adverse perinatal outcomes against ureaplasma urealyticum.

Estramustine-related hypocalcemia in patients with prostate carcinoma and osteoblastic metastases

We describe a patient with androgen-independent prostate cancer in whom hypocalcemia developed during treatment with estramustine. The patient's total serum calcium level before and after the initiation of estramustine was 8.3 and 4.3 mg/dL, respectively (normal range 8.4 to 10.2). This finding prompted us to review the calcium levels in 135 consecutive patients who were also undergoing treatment with a similar estramustine-containing regimen. We found that hypocalcemia had developed in 20% of these patients during treatment. We speculate that estramustine may cause hypocalcemia by inhibiting the mobilization of calcium and the action of the parathyroid hormone in the skeleton.

Sharable representation of clinical guidelines in GLIF: relationship to the Arden Syntax

Clinical guidelines are intended to improve the quality and cost effectiveness of patient care. Integration of guidelines into electronic medical records and order-entry systems, in a way that enables delivery of patient-specific advice at the point of care, is likely to encourage guidelines acceptance and effectiveness. Among the methodologies for modeling guidelines and medical decision rules, the Arden Syntax for Medical Logic Modules and the GuideLine Interchange Format version 3 (GLIF3) emphasize the importance of sharing encoded logic across different medical institutions and implementation platforms. These two methodologies have similarities and differences; in this paper we clarify their roles. Both methods can be used to support sharing of medical knowledge, but they do so in complementary situations. The Arden Syntax is suitable for representing individual decision rules in self-contained units called Medical Logic Modules (MLMs), which are usually implemented as event-driven alerts or reminders. In contrast, GLIF3 is designed for encoding complex multistep guidelines that unfold over time. As a consequence, GLIF3 has several mechanisms for complexity management and additional constructs that may require overhead unnecessary for expressing simple alerts and reminders. Unlike the Arden Syntax, GLIF3 encourages a top-down process of guideline modeling consisting of three levels that are created in order: Level 1 comprises a human-readable flowchart of clinical decisions and actions. Level 2 comprises a computable specification that can be verified for logical consistency and completeness; and Level 3 comprises an implementable specification that includes information required for local adaptation of guideline logic as well as for mapping guideline variables onto institutional medical records. A major emphasis of the current GLIF3 development process has been to create the computable specification that formally represents medical decision and eligibility criteria. We based GLIF3's formal expression language on the Arden Syntax's logic grammar, making the necessary extensions to the Arden Syntax's data structures and operators to support GLIF3's object-oriented data model. We discuss why the process of generating a set of MLMs from a GLIF-encoded guideline cannot be automated, why it can result in information loss, and why simple medical rules are best represented as individual MLMs. We thus show that the Arden Syntax and GLIF3 play complementary roles in representing medical knowledge for clinical decision support.

Cdc42 is a substrate for caspases and influences Fas-induced apoptosis

Fas-mediated apoptosis results in the activation of caspases, which subsequently cleave cellular substrates that are essential for normal cell viability. In the present study, we show that the Ras-related GTP-binding protein Cdc42 is susceptible to caspase-catalyzed proteolysis in a number of cell lines, including NIH3T3 fibroblasts, human breast cancer cells (e.g. T47D), and COS-7 cells. Both caspase-3 and caspase-7 were able to catalyze the cleavage of Cdc42, whereas caspase-6 and caspase-8 were without effect. The susceptibility to the caspase-stimulated degradation is specific; although Rac can also serve as a caspase substrate, neither Rho nor Ras is degraded. Caspase sensitivity is conferred by a consensus sequence (DXXD) that lies immediately upstream of the Rho insert regions (residues 122-134) of Cdc42 and Rac. The removal of a stretch of residues (120) that includes the insert region or site-directed mutagenesis of either aspartic acid 118 or 121 within a constitutively active background (i.e. Cdc42(F28L)) as well as a wild-type Cdc42 background yields Cdc42 molecules that provide a marked protection against Fas ligand-induced apoptosis. Overall, these results are consistent with a model in which Cdc42 acts downstream of Fas, perhaps to influence the rate of apoptosis, with the ultimate caspase-mediated degradation of Cdc42 then allowing for a maximal apoptotic response.

Effects and mechanisms of somatostatin analogs on apoptosis of pancreatic acinar cells in acute pancreatitis in mice

AIM

To investigate the effects of somatostatin analogs (SSa) on apoptosis of pancreatic acinar cells and apoptosis-regulated gene bax, and p53 in treating acute pancreatitis in mice.

METHODS

In cerulein-induced pancreatitis, with or without treatment of somatostatin, analogs (Octreotide) in CD-1 (BALB/c x DBetaAlpha/1) mice, apoptosis of pancreatic acinar cells was detected by using the TdT-mediated dUTP nick-end labeling (TUNEL) method, and the expression of apoptosis-regulated gene bax and p53 was determined by using the streptavidin-peroxidase immunohistochemical technique and the RT-PCR method, respectively.

RESULTS

On HE staining, acinar cells in the pancreas showed pyknotic nuclei and the formation of apoptotic bodies, which are the typical morphological features of apoptosis. Regarding TUNEL use, the apoptotic index of pancreatic acinar cells in the non-treated group at 5 and 14 h after induction of acute pancreatitis was significantly lower than those of the SSa-treated group, respectively (P < 0.01). On immunohistochemistry and RT-PCR, there was an expression of neither bax nor p53 in normal pancreatic tissues. The expression of bax in the SSa-treated group at 5 and 14 h after treatment of SSa was markedly higher than those of the non-treated group, respectively (P < 0.01), but there was no significant difference in the expression of p53 between the SSa-treated group and the non-treated group.

CONCLUSIONS

The induction of apoptosis in pancreatic acinar cells injury to reduce inflammatory reaction might be one of the mechanisms of SSa in treating acute pancreatitis in mice, and the mechanisms of apoptosis probably correlated with the expression of apoptosis-regulated gene bax, but have no relationship with the expression of p53.

Toward a representation format for sharable clinical guidelines

Clinical guidelines are being developed for the purpose of reducing medical errors and unjustified variations in medical practice, and for basing medical practice on evidence. Encoding guidelines in a computer-interpretable format and integrating them with the electronic medical record can enable delivery of patient-specific recommendations when and where needed. Since great effort must be expended in developing high-quality guidelines, and in making them computer-interpretable, it is highly desirable to be able to share computer-interpretable guidelines (CIGs) among institutions. Adoption of a common format for representing CIGs is one approach to sharing. Factors that need to be considered in creating a format for sharable CIGs include (i) the scope of guidelines and their intended applications, (ii) the method of delivery of the recommendations, and (iii) the environment, consisting of the practice setting and the information system in which the guidelines will be applied. Several investigators have proposed solutions that improve the sharability of CIGs and, more generally, of medical knowledge. These approaches can be useful in the development of a format for sharable CIGs. Challenges in sharing CIGs also include the need to extend the traditional framework for disseminating guidelines to enable them to be integrated into practice. These extensions include processes for (i) local adaptation of recommendations encoded in shared generic guidelines and (ii) integration of guidelines into the institutional information systems.

[Temperature distribution of tumor tissues irradiated by microwave]

This paper calculates the temperature distribution of the spherical tumor, applying the theory of electromagnetic scattering and the thermal conductivity of tissues (including normal tissues and tumor tissues). Our research work will be of some value in clinical medicine.

A randomized, controlled, single-blind trial of leflunomide in the treatment of rheumatoid arthritis

The efficacy and safety of leflunomide (LEF) in the treatment of rheumatoid arthritis (RA) were evaluated and the comparison with methotrexate's (MTX's) was performed in a 12-week, single-blind, randomized, parallel trial for treating 81 patients with RA. There were 56 cases in LEF group and 25 cases in MTX group. The dose of LEF was 20 mg per day and MTX 15 mg per week. All patients took oxaproxin simultaneously at the 4th to 6th week after the trail. The results showed that the general effective rate and notable effective rate were 94.64% and 73.21% in LEF group, 72% and 44% in MTX group, respectively, with the differences being statistically significant between the two groups (P < 0.05). LEF and oxaprozin could obviously improve the symptoms, signs and joint functions. The incidence of side reactions was lower in LEF group (17.86%) than in MTX group (40.00%, P < 0.05). LEF had a good therapeutic effect for RA, especially for refractory RA and had slight side reactions, and could be regarded as a superior immunosuppressive agent used in the treatment of RA and other connective tissue diseases.

Using features of Arden Syntax with object-oriented medical data models for guideline modeling

Computer-interpretable guidelines (CIGs) can deliver patient-specific decision support at the point of care. CIGs base their recommendations on eligibility and decision criteria that relate medical concepts to patient data. CIG models use expression languages for specifying these criteria, and define models for medical data to which the expressions can refer. In developing version 3 of the GuideLine Interchange Format (GLIF3), we used existing standards as the medical data model and expression language. We investigated the object-oriented HL7 Reference Information Model (RIM) as a default data model. We developed an expression language, called GEL, based on Arden Syntax's logic grammar. Together with other GLIF constructs, GEL reconciles incompatibilities between the data models of Arden Syntax and the HL7 RIM. These incompatibilities include Arden's lack of support for complex data types and time intervals, and the mismatch between Arden's single primary time and multiple time attributes of the HL7 RIM.

Activity-dependent regulation of substance P expression and topographic map maintenance by a cholinergic pathway

We have assessed the role of activity in the adult frog visual system in modulating two aspects of neuronal plasticity: neurotransmitter expression and topographic map maintenance. Chronic treatment of one tectal lobe with the non-NMDA receptor antagonist, 6-cyano-7-nitroquinoxaline-2,3-dione decreased the percentage of substance P-like immunoreactive (SP-IR) tectal cells in the untreated lobe while disrupting topographic map formation in the treated one. Treatment with the NMDA receptor antagonist d-(-)-2-amino-5-phosphonovaleric acid (d-AP-5) disrupted the topographic map but had no affect on SP-IR cells. These results indicate that maintenance of the topographic map is dependent on direct input from the glutamatergic retinal ganglion cells, whereas substance P (SP) expression is being regulated by a pathway that relays activity from one tectal lobe to the other. Such a pathway is provided by the cholinergic nucleus isthmi, which is reciprocally connected to the ipsilateral tectum and sends a projection to the contralateral one. Mecamylamine and atropine, antagonists of nicotinic and muscarinic receptors, respectively, were used together to block all cholinergic activity or alone to block receptor subclass activity. All three treatments decreased SP expression and disrupted the topographic map in the treated tectal lobe. We conclude that both SP expression and topographic map maintenance in the adult optic tectum are activity-dependent processes. Although our results are consistent with the maintenance of the topographic map through an NMDA receptor-based mechanism, they suggest that SP expression is regulated by a cholinergic interaction that depends on retinal ganglion cell input only for its activation.

Using scenarios in chronic disease management guidelines for primary care

The Prodigy system is a guideline-based decision-support system designed to assist general practitioners in England choose the appropriate therapeutic action for their patients. As part of the system, we developed a novel model for encoding clinical guidelines for managing patients with chronic diseases such as asthma and hypertension. The model structures a guideline as a set of choices to be made by the clinician. It models patient scenarios which drive decision making and are used to synchronize the management of a patient with guideline recommendations. The model is robust with respect to available input data and leaves the control of decision-making to the clinician. We have built execution engines to verify the computability of the model. We intend to test the model integrated in up to 200 live systems from at least four system vendors in English General practice.

GLIF3: the evolution of a guideline representation format

The Guideline Interchange Format (GLIF) is a language for structured representation of guidelines. It was developed to facilitate sharing clinical guidelines. GLIF version 2 enabled modeling a guideline as a flowchart of structured steps, representing clinical actions and decisions. However, the attributes of structured constructs were defined as text strings that could not be parsed, and such guidelines could not be used for computer-based execution that requires automatic inference. GLIF3 is a new version of GLIF designed to support computer-based execution. GLIF3 builds upon the framework set by GLIF2 but augments it by introducing several new constructs and extending GLIF2 constructs to allow a more formal definition of decision criteria, action specifications and patient data. GLIF3 enables guideline encoding at three levels: a conceptual flowchart, a computable specification that can be verified for logical consistency and completeness, and an implementable specification that can be incorporated into particular institutional information systems.

Guideline classification to assist modeling, authoring, implementation and retrieval

The National Guideline Clearinghouse (NGC) and its guideline classification system are significant contributions to the study of clinical practice guidelines (CPGs) and their incorporation into routine clinical care. The NGC classification system is primarily designed to support guideline retrieval. We believe that a guideline classification system should also support identification of features that relate to incorporation of executable CPGs into computer-based applications for sharing and delivering guideline-based advice. We have developed a proposed expansion of the NGC guideline classification for this purpose. The axes of the proposed scheme have implications for designing formal models and structures for representing and authoring CPGs. This scheme also has implications for future research.

Development and regulation of substance P expression in neurons of the tadpole optic tectum

Activity-dependent synaptic plasticity is characteristic of developing visual systems. Using the frog retinotectal system, we investigated the extent to which afferent input affects neurotransmitter expression in a target structure. We have concentrated on a particular subpopulation of tectal cells that is immunoreactive to substance P (SP). Early in development, SP expression in tectal neurons was restricted to the anterior lateral region of the tectum. As tadpoles developed, this expression expanded into progressively more posterior and medial regions in a manner that closely followed the gradient of tectal maturation. At all times, however, anterior and lateral tectal regions had a greater percent of SP-like immunoreactive (SP-ir) cells than posterior and medial ones. Horseradish peroxidase (HRP) labeling of the retinal ganglion cell projection in conjunction with SP immunocytochemistry demonstrated that innervation by retinal ganglion cell terminals preceded the expression of SP by tectal cells. This suggested that the optic nerve may influence SP differentiation and/or expression. In support of this idea, transection of the optic nerve resulted in a decrease in SP expression in the deafferented tectal lobe of tadpoles. This result, opposite to that seen previously in the adult, also indicates that optic nerve-dependent regulation of SP expression in the developing and mature systems occurs through different pathways.

Epidermal growth factor protects epithelial cells against Fas-induced apoptosis. Requirement for Akt activation

Chemotherapeutic drugs that damage DNA kill tumor cells, in part, by inducing the expression of a death receptor such as Fas or its ligand, FasL. Here, we demonstrate that epidermal growth factor (EGF) stimulation of T47D breast adenocarcinoma and embryonic kidney epithelial (HEK293) cells protects these cells from Fas-induced apoptosis. EGF stimulation of epithelial cells also inhibited Fas-induced caspase activation and the proteolysis of signaling proteins downstream of the EGF receptor, Cbl and Akt/protein kinase B (Akt). EGF stimulation of Akt kinase activity blocked Fas-induced apoptosis. Expression of activated Akt in MCF-7 breast adenocarcinoma cells was sufficient to block Fas-mediated apoptosis. Inhibition of EGF-stimulated extracellular signal-regulated kinase (ERK) activity did not affect EGF protection from Fas-mediated apoptosis. The findings indicate that EGF receptor stimulation of epithelial cells has a significant survival function against death receptor-induced apoptosis mediated by Akt.

Integrating a modern knowledge-based system architecture with a legacy VA database: the ATHENA and EON projects at Stanford

We present a methodology and database mediator tool for integrating modern knowledge-based systems, such as the Stanford EON architecture for automated guideline-based decision-support, with legacy databases, such as the Veterans Health Information Systems & Technology Architecture (VISTA) systems, which are used nation-wide. Specifically, we discuss designs for database integration in ATHENA, a system for hypertension care based on EON, at the VA Palo Alto Health Care System. We describe a new database mediator that affords the EON system both physical and logical data independence from the legacy VA database. We found that to achieve our design goals, the mediator requires two separate mapping levels and must itself involve a knowledge-based component.

Effect of Sinomenine on IL-8, IL-6, IL-2 produced by peripheral blood mononuclear cells

The effect of Sinomenine on IL-8, IL-6, IL-2 and mIL-2R produced by peripheral blood mononuclear cells was investigated by using cell culture, radioimmunoassay and flow cytometry. It was showed that production of IL-8 and mIL-2R was inhibited, but the levels of IL-6 were enhanced by Sinomenine. Our results also demonstrated that Sinomenine did not have any effect on the production of IL-2. The study demonstrated that Sinomenine was able to regulate the production of cytokines. This may be one of the mechanisms by which Sinomenine works on rheumatoid arthritis.

bcl-2 expression confers androgen independence in androgen sensitive prostatic carcinoma

Expression of the bcl-2 proto-oncogene is associated with the progression of prostate cancer to androgen-independence. Dunning R3327G (DG) cells were engineered to express high levels of bcl-2 protein. The parental DG (DG-P) cell line and bcl-2 transfectant (DG-B) clones were grown as subcutaneous tumor explants in male athymic nude mice. The rate of tumor growth after castration was significantly lower in DG-P tumors but was unaffected in DG-B tumors. The proliferative indices (PI) in DG-P and DG-B tumors were similar, however, apoptotic indices (ApI) were significantly lower in DG-B tumors before castration. Following castration the PI and ApI decreased significantly in DG-P but not DG-B tumors. Bax upregulation was not observed in the DG-P or DG-B tumors, but did occur in the ventral prostate, after castration. These findings support a role for bcl-2 expression in conferring androgen-independent growth during prostate cancer progression.

In vivo nuclear magnetic resonance study of the osmoregulation of phosphocholine-substituted beta-1,3;1,6 cyclic glucan and its associated carbon metabolism in Bradyrhizobium japonicum USDA 110

A phosphocholine-substituted beta-1,3;1,6 cyclic glucan (PCCG), an unusual cyclic oligosaccharide, has been isolated from Bradyrhizobium japonicum USDA 110 (D. B. Rolin, P. E. Pfeffer, S. F. Osman, B. S. Swergold, F. Kappler, and A. J. Benesi, Biochim. Biophys. Acta 1116:215-225, 1992). Data presented here suggest that PCCG synthesis is dependent on the carbon metabolism and that osmotic regulation of its biosynthesis parallels regulation of membrane-derived oligosaccharide biosynthesis observed in Escherichia coli (E. P. Kennedy, M. K. Rumley, H. Schulman, and L. M. G. van Golde, J. Biol. Chem. 251:4208-4213, 1976) and Agrobacterium tumefaciens (G. A. Cangelosi, G. Martinetti, and E. W. Nester, J. Bacteriol. 172:2172-2174, 1990). Growth of B. japonicum USDA 110 cells in the reference medium at relatively low osmotic pressures (LO) (65 mosmol/kg of H2O) caused a large accumulation of PCCG and unsubstituted beta-1,3;1,6 cyclic glucans (CG). Sucrose and polyethylene glycol, nonionic osmotica, reduce all growth rates and inhibit almost completely the production of PCCG at high osmotic pressures (HO) above 650 and 400 mosmol/kg of H2O), respectively. We used in vivo 13C nuclear magnetic resonance spectroscopy to identify the active osmolytes implicated in the osmoregulation process. The level of alpha,alpha-trehalose in B. japonicum cells grown in autoclaved or filter-sterilized solutions remained constant in HO (0.3 M sucrose or 250 g of polyethylene glycol 6000 per liter) medium. Significant amounts of glycogen and extracellular polysaccharides were produced only when glucose was present in the autoclaved HO 0.3 M sucrose media. The results of hypo- and hyperosmotic shocking of B. japonicum USDA 110 cells were monitored by using in vivo 31P and 13C nuclear magnetic resonance spectroscopy. The first observed osmoregulatory response of glycogen-containing cells undergoing hypoosmotic shock was release of P(i) into the medium. Within 7 h, reabsorption of P(i) was complete and production of PCCG was initiated. After 12 h, the PCCG content had increased by a factor of 7. Following the same treatment, cells containing little or no glycogen released trehalose and failed to produce PCCG. Thus the production of PCCG/CG in response to hypoosmotic shocking of stationary-phase cells was found to be directly linked to the interconversion of stored glycogen. Hyperosmotic shocking of LO-grown stationary-phase cells with sucrose had no effect on the content of previously synthesized CG/PCCG. The PCCG/CG content and its osmotically induced biosynthesis are discussed in terms of carbon metabolism and a possible role in hypoosmotic adaptation in B. japonicum USDA 110.

TQuery: a context-sensitive temporal query language

Users of electronic medical databases request pertinent information by recasting their clinical questions into a formal database query language. Because the query language is the user's only access to the data, the query language must be powerful enough to enable users to express their data requirements. However, a competing need is for the query language to be restrictive enough so that queries can have unambiguous semantics and the query processor can generate correct answers. We describe a query language, called TQuery , that was designed specifically to formulate database queries that are dependent on temporal and contextual relationships. TQuery specifications express contextual constraints without the need to explicitly reference calendar dates. TQuery is the database query language used to retrieve patient data from an object-oriented electronic patient medical-record system called the temporal network (TNET). TNET and TQuery were developed to support the real-time temporal reasoning and representation needs of a LISP workstation-based medical expert system.

A chromogranin A-derived peptide differentially regulates the secretion of calcitonin gene products

We studied the regulation of the secretion of CT and CGRP by chromogranin A (CgA)-derived peptides in a human lung tumor cell line. The amino-terminal peptide of CgA, CgA1-40, stimulated the secretion of CGRP and inhibited the secretion of CT; both effects occurred in a dose-dependent manner. These studies demonstrate a differential effect of a CgA-derived peptide on two products of the CT gene, CT itself and CGRP. CgA may be processed at its multiple dibasic sites to peptides that specifically regulate the secretion of its coresident hormones, in this case two calcitonin gene products that are present in the same secretory vesicle. This novel mechanism represents a new pathway for the control of calcium regulating hormones.

PTHrP secretion is stimulated by CT and inhibited by CgA peptides

We studied the regulation of the secretion in vitro of the parathyroid hormone-related protein (PTHrP) associated with the hypercalcemia of malignancy by Chromogranin A (CgA)-derived peptides and by human calcitonin (CT) in the BEN human lung tumor cell line. The amino terminal peptide of CgA, CgA1-40, inhibited the secretion of PTHrP, whereas other peptides had no such effect. Human CT stimulated the secretion of PTHrP, whereas other hormones had no such effect. Both effects occurred in a dose-dependent manner. These studies reveal novel regulatory pathways among peptides and proteins that are commonly associated with each other and can have paracrine interactions. CgA may be processed at its multiple dibasic sites to peptides that regulate the secretion of its co-resident hormones, in this case PTHrP. In addition to a paracrine effect, CT may be clinically useful as a provocative agent for PTHrP secretion. Complex interactions are present among the calcium-regulating hormones and their associated proteins.

Prognosis of nasopharyngeal carcinoma by Epstein-Barr virus antibody titer

A total of 433 samples of serum were collected from 305 patients with histopathologically proved anaplastic nasopharyngeal carcinoma (NPC). Antibodies against viral capsid antigens (VCA) of Epstein-Barr (EB) virus were titrated by means of indirect fluorescent antibody technique, using P3HR-1 cells as the target. High anti-VCA antibody titer in patients with NPC was found beginning to decline at the end of radiotherapy. Most (66.7%) of the patients were found to have a detectable reduction in antibody titer within six months after radiotherapy. Persistent high antibody titer after treatment correlates to high risk of the recurrence of the disease. This prognostic importance of anti-VCA titer becomes apparent at the end of radiotherapy, significant (P less than .05) within one year after treatment, and highly significant (P less than .0005) over one year after treatment.

Cortisol modification of HeLa 65 alkaline phosphatase. Decreased phosphate content of the induced enzyme

Alkaline phosphatase activity of HeLa cells is increased 5-20-fold during growth in medium with cortisol. The increase in enzyme activity is due to an enhanced catalytic efficiency rather than an increase in alkaline phosphatase protein in induced cells. In the present study the chemical composition of control and induced forms of alkaline phosphatase were investigated to determine the enzyme modification that may be responsible for the increased catalytic activity. HeLa alkaline phosphatase is a phosphoprotein and the induced form of the enzyme has approximately one-half of the phosphate residues associated with control enzyme. The decrease in phosphate residues of the enzyme apparently alters its catalytic activity. Other chemical components of purified alkaline phosphatase from control and induced cells are similar; these include sialic acid, hexosamine and sulfhydryl residues.

Differential effects of 8-anilino-1-naphthalenesulfonate upon binding of oxidized and reduced flavines by bacterial luciferase

Upon binding to bacterial luciferase, both the absorption and the fluorescence excitatiom maxima of 8-anilino-1-naphthalensulfonate (ANS) shift from 353 to 370 nm while the fluorescence emission optimum shifts from 540 to 480 nm, and the fluorescence quantum yield increases from 0.003 to 0.39, indicating that the environment of the ANS binding site is hydrophobic. ANS binds to luciferase with dissociation constants of 1.9 X 10(-5) and 2.3 X 10(-5) M at 5 and 23 degrees, repsectively. As with both oxidized flavine mononucleotide (FMN) and reduced flavine mononucleotide (FMNH2), ANS also binds to luciferase with a stoichiometry of 1 site per dimeric luciferase molecule. ANS acts as a luciferase inhibitor, competitive with FMNH2, with an inhibitor constant of 2.3 X 10(-5) M at 23 degrees. However, the binding of ANS does not significantly displace FMN from binding to luciferase. Interactions of FMN and FMNH2 with luciferase are thus differentially regulated by the ANS binding.