Customization in a unified framework for summarizing medical literature.

OBJECTIVE: We present the summarization system in the PErsonalized Retrieval and Summarization of Images, Video and Language (PERSIVAL) medical digital library. Although we discuss the context of our summarization research within the PERSIVAL platform, the primary focus of this article is on strategies to define and generate customized summaries. METHODS AND MATERIAL: Our summarizer employs a unified user model to create a tailored summary of relevant documents for either a physician or lay person. The approach takes advantage of regularities in medical literature text structure and content to fulfill identified user needs. RESULTS: The resulting summaries combine both machine-generated text and extracted text that comes from multiple input documents. Customization includes both group-based modeling for two classes of users, physician and lay person, and individually driven models based on a patient record. CONCLUSIONS: Our research shows that customization is feasible in a medical digital library.

Regulation of 15-hydroxy prostaglandin dehydrogenase by corticotrophin-releasing hormone through a calcium-dependent pathway in human chorion trophoblast cells.

Prostaglandins (PGs) play a crucial role in mediating parturition events, and their synthesis and metabolism are regulated by PG H synthase and 15-hydroxy-PG dehydrogenase (PGDH), respectively. Within the chorion tissue, it is the actions of PGDH that predominate. Throughout gestation, the fetal membranes secrete increasing amounts of CRH. We hypothesized that CRH, produced locally in the chorion, could act to modulate PGDH activity throughout gestation. To investigate this, we obtained Percoll-purified human chorion and placental trophoblast cells from uncomplicated term pregnancies and cultured them for 72 h. Activity of PGDH was assessed by incubation (4 h) with PGF(2alpha) (282 nM) and measurement of conversion to 13,14-dihydro-15-keto PG F(2alpha). Dose-response curves were constructed for the chorion cell cultures with CRH or 8-bromo-cAMP. To investigate the role of CRH and calcium, cells were treated with either astressin, a CRH antibody, BAPTA, or EGTA. CRH (0-1 micro M) had no effect on PGDH activity; however, cells treated with astressin (10 micro M), with or without exogenous CRH (1 micro M), and cells treated with a CRH antibody showed a significant decrease in PGDH activity. 8-Bromo-cAMP (0-1 mM) had no effect on 13,14-dihydro-15-keto PG F(2alpha) output in chorion trophoblast cells but significantly decreased output from placental trophoblast cells. Cells treated with either BAPTA-AM or EGTA had significantly reduced PGDH activity; and, at intermediate concentrations of chelator, exogenous CRH restored PGDH activity. We suggest that, in chorion trophoblast cells, endogenously produced CRH exerts a tonic stimulatory effect on PGDH activity and may help maintain a metabolic barrier, preventing the transfer of bioactive PGs from the chorioamnion to the myometrium.

Periplasmic production of correctly processed human growth hormone in Escherichia coli: natural and bacterial signal sequences are interchangeable.

We have studied the synthesis, secretion, and processing of human growth hormone (hGH) in Escherichia coli transformed with plasmids engineered for the expression of hGH as a secreted product. In one plasmid, pPreHGH207-2, the coding sequence of the natural hGH precursor (pre-hGH) is placed under the control of the E. coli trp promoter. In a second plasmid, pAPH-1, a DNA fragment containing the E. coli alkaline phosphatase promoter and signal sequence codons is fused to the mature hGH coding sequence (pho-hGH). Most of the hGH was present in the osmotic shock fluids of E. coli cells containing either plasmid, indicating transport to the periplasmic space. Amino acid sequencing of the N termini of the pre-hGH and pho-hGH gene products revealed that both were processed correctly. Electrophoretic analysis of these polypeptides on reducing and nonreducing sodium dodecyl sulfate (SDS)-polyacrylamide (PA) gels indicates that periplasmic hGH is monomeric and contains the same two disulfide bonds as authentic hGH.

Assessment of different methods to detect increased autochthonous production of immunoglobulin G and oligoclonal immunoglobulins in multiple sclerosis.

The formulae for immunoglobulin G (IgG) synthesis rate, IgG(loc), IgG index, and IgG extended index in determining increased autochthonous production (intra-blood-brain barrier synthesis) of IgG was assessed in 50 chronic progressive multiple sclerosis patients. The results of all four formulae clearly show elevated intra-blood-brain barrier IgG synthesis in 35 patients, 94% of whom had oligoclonal immunoglobulins detected by the method of isoelectric focusing with immunofixation and silver staining (IEF-IS). The results from the four formulae are all normal in seven patients (none have oligoclonal immunoglobulins by IEF-IS) and are discordant in eight patients (five have oligoclonal immunoglobulins by IEF-IS). Whenever intra-blood-brain barrier synthesis of IgG is suspected, IEF-IS should be used to assay for oligoclonal immunoglobulins because this method is more sensitive than agarose electrophoresis with either Coomassie blue dye or silver stain (94% vs. 74% vs. 54%).

Generation and evaluation of intraoperative inferences for automated health care briefings on patient status after bypass surgery.

OBJECTIVE: The authors present a system that scans electronic records from cardiac surgery and uses inference rules to identify and classify abnormal events (e.g., hypertension) that may occur during critical surgical points (e.g., start of bypass). This vital information is used as the content of automatically generated briefings designed by MAGIC, a multimedia system that they are developing to brief intensive care unit clinicians on patient status after cardiac surgery. By recognizing patterns in the patient record, inferences concisely summarize detailed patient data. DESIGN: The authors present the development of inference rules that identify important information about patient status and describe their implementation and an experiment they carried out to validate their correctness. The data for a set of 24 patients were analyzed independently by the system and by 46 physicians. MEASUREMENTS: The authors measured accuracy, specificity, and sensitivity by comparing system inferences against physician judgments, in cases where all three physicians agreed and against the majority opinion in all cases. RESULTS: For laboratory inferences, evaluation shows that the system has an average accuracy of 98 percent (full agreement) and 96 percent (majority model). An analysis of interrater agreement, however, showed that physicians do not agree on abnormal hemodynamic events and could not serve as a gold standard for evaluating hemodynamic events. Analysis of discrepancies reveals possibilities for system improvement and causes of physician disagreement. CONCLUSIONS: This evaluation shows that the laboratory inferences of the system have high accuracy. The lack of agreement among physicians highlights the need for an objective quality-assurance tool for hemodynamic inferences. The system provides such a tool by implementing inferencing procedures established in the literature.

Effects of lung volume on lung and chest wall mechanics in rats.

To investigate the effect of lung volume on chest wall and lung mechanics in the rats, we measured the impedance (Z) under closed- and open-chest conditions at various positive end-expiratory pressures (0-0.9 kPa) by using a computer-controlled small-animal ventilator (T. F. Schuessler and J. H. T. Bates. IEEE Trans. Biomed. Eng. 42: 860-866, 1995) that we have developed for determining accurately the respiratory Z in small animals. The Z of total respiratory system and lungs was measured with small-volume oscillations between 0.25 and 9.125 Hz. The measured Z was fitted to a model that featured a constant-phase tissue compartment (with dissipation and elastance characterized by constants G and H, respectively) and a constant airway resistance (Z. Hantos, B. Daroczy, B. Suki, S. Nagy, and J. J. Fredberg. J. Appl. Physiol. 72: 168-178, 1992). We matched the lung volume between the closed- and open-chest conditions by using the quasi-static pressure-volume relationship of the lungs to calculate Z as a function of lung volume. Resistance decreased with lung volume and was not significantly different between total respiratory system and lungs. However, G and H of the respiratory system were significantly higher than those of the lungs. We conclude that chest wall in rats has a significant influence on tissue mechanics of the total respiratory system.

Multiple primary malignant neoplasms.

The occurrence of multiple malignant tumours has been recorded, usually as individual cases but also in groups from tumour registries or autopsy studies. A personal series of 71 cases encountered in the follow-up clinics of two District General Hospitals is presented. Cases of multiple skin tumours, and of intestinal growths associated with pernicious anaemia, ulcerative colitis and familial polyposis have been excluded. Review of the literature has been carried out and possible aetiological factors have been considered. The importance of the functions of the tumour surveillance mechanism is emphasized, and the possibility of depression of the defence mechanism by major surgery, is considered to be of importance. Assessment of the patient's defence mechanisms may be as important as grading and staging the tumours.

Mechanism of the neurotoxicity of 1-methyl-4-phenylpyridinium (MPP+), the toxic bioactivation product of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP).

It is widely believed that the nigrostriatal toxicity of MPTP is due to its oxidation by brain monoamine oxidase first to MPDP+, and eventually to MPP+. Following uptake by the synaptic dopamine reuptake system, it is concentrated in the matrix of striatal mitochondria by an energy-dependent carrier, energized by the electrical gradient of the membrane. At the very high intramitochondrial concentrations thus reached, MPP+ combines with NADH dehydrogenase at a point distal to its iron-sulfur clusters but prior to the Q10 combining site. This leads to cessation of oxidative phosphorylation, ATP depletion, and cell death. Other pyridine derivatives act similarly on NADH dehydrogenase but they are not acutely toxic unless concentrated by the MPP+ carrier.

Clinical governance for nurses: smoking cessation interventions.

AIM: To raise clinical governance issues by drawing on a Health Education Authority-sponsored review of the style, form and effect of a smoking cessation service in north west Lancashire. This service operated for five years before the government's decision to set up smoking cessation services. METHOD: A postal survey was undertaken of 800 clients. RESULTS: 193 people responded. Of these, 132 (68 per cent) claimed to be helped by the service. Proactive telephone contact, carbon monoxide monitoring, the six-week course, nicotine replacement therapy, and reading materials were well received. Thirty six per cent of the respondents were not smoking at the time of the survey. CONCLUSION: Nursing staff are increasingly expected to provide smoking cessation support. The government is funding this work and monitoring the number of clients helped, rather than the quality of the service. However, in terms of clinical governance, the quality of the service is crucially important.

Clinical trial: music reduces anxiety levels in patients attending for endoscopy.

BACKGROUND: Patients attending for endoscopy are generally anxious and worried. AIMS: To examine whether music reduced anxiety levels in patients attending for endoscopic procedures. METHODS: Prospective randomized controlled trial of 180 patients (M:F 81:99). The effect of age (< or = or >51 years) and procedure (gastroscopy or flexible sigmoidoscopy/colonoscopy) on anxiety levels (state-trait anxiety inventory) on arrival in the unit and immediately before the endoscopy procedure, after listening to music or no music (control group) for the same period. RESULTS: At baseline, anxiety levels were not influenced by age (< or =51 years, n = 56:42.21 +/- 9.18; >51 years, n = 124:39.99 +/- 10.13 (P = 0.15) or procedure: gastroscopy, n = 87:39.43 +/- 9.9, flexible sigmoidoscopy/colonoscopy: n = 93:41.86 +/- 9.75 (P = 0.98). No difference was found in anxiety scores in the control group (n = 88) at baseline and immediately pre-endoscopy (P = 0.243), but music led to a significant reduction in anxiety scores (n = 92), which was maintained for all age groups irrespective of procedure (all P < 0.0001). CONCLUSIONS: Anxiety levels in patients attending for endoscopy were not influenced by age or procedure, but were significantly reduced by listening to music compared to controls. The availability of music within the endoscopy unit is a simple strategy that will improve the well-being of patients.