Amylase-resistant starch plus oral rehydration solution for cholera

BACKGROUND

Although standard glucose-based oral rehydration therapy corrects the dehydration caused by cholera, it does not reduce the diarrhea. Short-chain fatty acids, which are produced in the colon from nonabsorbed carbohydrates, enhance sodium absorption. We conducted a study to determine the effects of an orally administered, nonabsorbed starch (i.e., one resistant to digestion by amylase) on fecal fluid loss and the duration of diarrhea in patients with cholera.

METHODS

We randomly assigned 48 adolescents and adults with cholera to treatment with standard oral rehydration therapy (16 patients), standard therapy and 50 g of rice flour per liter of oral rehydration solution (16 patients), or standard therapy and 50 g of high-amylose maize starch, an amylase-resistant starch, per liter of oral rehydration solution (16 patients). The primary end points were fecal weight (for every 12-hour period during the first 48 hours after enrollment) and the length of time to the first formed stool.

RESULTS

The mean (+/-SD) fecal weights in the periods 12 to 24 hours, 24 to 36 hours, and 36 to 48 hours after enrollment were significantly lower in the resistant-starch group (2206+/-1158 g, 1810+/-1018 g, and 985+/-668 g) than in the standard-therapy group (3251+/-766 g, 2621+/-1149 g, and 2498+/-1080 g; P=0.01, P= 0.04, and P=0.001, respectively). From 36 to 48 hours after enrollment, fecal weight was also significantly lower with the resistant-starch therapy than with the rice-flour therapy (985+/-668 g vs. 1790+/-866 g, P=0.01). The mean duration of diarrhea was significantly shorter with the resistant-starch therapy (56.7+/-18.6 hours) than with standard therapy alone (90.9+/-29.8 hours, P=0.001) or the rice-flour therapy (70.8+/-20.2 hours, P=0.05). Fecal excretion of starch was higher with the resistant-starch therapy (32.6+/-30.4) than with the standard therapy (11.7+/-4.1 g, P=0.002) or the rice-flour therapy (15.1+/-8.4 g, P=0.01).

CONCLUSIONS

The addition of a resistant starch to oral rehydration solution reduces fecal fluid loss and shortens the duration of diarrhea in adolescents and adults with cholera.

Liver transplantation with monosegments

BACKGROUND

Shortage of size-matched pediatric donors led to the development of surgical techniques to reduce or split livers and thus increase the potential pool of donors. Despite this, neonatal transplantation remains a problem because of the small size of the recipients. Further reduction of the left lateral segment is possible to provide a single segment graft (segment III). We report our experience of transplanting 6 babies using this technique.

METHODS

Of 310 children transplanted in our center between October 1989 and March 1998, 6 patients, 2 male and 4 female, median age 37.5 days (range 5 to 92 days), median weight 3.45 kg (range 2.45 to 5.46 kg) were transplanted with a monosegment. The cause of liver failure was neonatal hemochromatosis in 4, retransplantation for hepatic artery thrombosis in 1, and hepatitis B in one. The donor liver was reduced or split to a left lateral segment. Segment II was then resected and discarded before transplantation.

RESULTS

Overall, graft and patient survival is 83.3%. Five patients are alive with good graft function at a mean follow-up of 30.4 months (range 8 to 82 months). One child who was transplanted for hepatic artery thrombosis died from sepsis and multiorgan failure 48 hrs after transplant. None of the survivors had vascular or biliary complications.

CONCLUSIONS

Monosegment liver transplantation with segment III appears to be a satisfactory option for treating small babies with liver failure.

Exploring the UMLS: a rough sets based theoretical framework

The Unified Medical Language System (UMLS) [1] has a unique and leading position in the evolution of thesauri and metathesauri. Features that set it apart are: its composition from more than fifty component health care vocabularies; the sophisticated UMLS ontology linking the Metathesaurus with structures such as the Semantic Network and the SPECIALIST lexicon; and the high level of social collaboration invested in its construction and growth. It is our thesis that in order to successfully harness such a complex vocabulary for text retrieval we need sophisticated methods derived from a deeper understanding of the UMLS system. Thus we propose a theoretical framework based on the theory of rough sets, that supports the systematic and exploratory investigation of the UMLS Metathesaurus for text retrieval. Our goal is to make it more feasible for individuals such as patients and health care professionals to access relevant information at the point of need.

Ocular malaria. A clinical and histopathologic study

PURPOSE

Clinical and histopathologic findings of ocular lesions in malaria rarely have been described. This study reports lesions in three patients with malaria, with a histopathologic study of eyes obtained at autopsy of one of these patients.

METHODS

Various ocular lesions were documented in three patients with malarial infection, with histopathologic study of one patient. In all three patients, the diagnosis of malaria was confirmed by the demonstration of malarial parasites in peripheral smears and by fluorescent microscopy of acridine orange-stained buffy coat preparations of venous blood.

RESULTS

Multiple superficial blotchy retinal hemorrhages over the posterior pole were seen in the first patient, whereas acute bilateral panuveitis and secondary glaucoma were seen in the second, which on resolution showed multiple blotchy superficial retinal hemorrhages with perivasculitis. The third patient had cerebral malaria and was found to have subconjunctival and retinal hemorrhages. This patient died of pulmonary thromboembolism, and the eyes were obtained at autopsy. On gross examination, there were multiple retinal hemorrhages in the posterior pole. Histopathologic study showed cytoadherence of parasitized erythrocytes as well as schizonts and gametocytes of Plasmodium vivax within the retinal and choroidal blood vessels.

CONCLUSION

The authors' findings suggest that patients with unexplained blotchy retinal hemorrhages should be investigated for malarial infection, especially if they reside or have travelled in endemic areas.

Retrieval feedback for query design in MEDLINE. A comparison with expert network and LLSF approaches

Query design is a vibrant research focus in information retrieval. The objective is to modify a user's original query into one that is more effective for retrieval. Researchers have proposed and investigated a variety of strategies to support query design in MEDLINE. This paper examines a query design method built within the framework of retrieval feedback. In particular, the effectiveness of this method is compared with the effectiveness of competing methods that utilize query mapping functions constructed in an expert network or built using the Linear Least Squares Fit approach. The comparison indicates that retrieval feedback offers an approach that is just as effective as these alternative approaches. Moreover, it has the advantage of being simpler to implement.

Retrieval feedback in MEDLINE

OBJECTIVE

To investigate a new approach for query expansion based on retrieval feedback. The first objective in this study was to examine alternative query-expansion methods within the same retrieval-feedback framework. The three alternatives proposed are: expansion on the MeSH query field alone, expansion on the free-text field alone, and expansion on both the MeSH and the free-text fields. The second objective was to gain further understanding of retrieval feedback by examining possible dependencies on relevant documents during the feedback cycle.

DESIGN

Comparative study of retrieval effectiveness using the original unexpanded and the alternative expanded user queries on a MEDLINE test collection of 75 queries and 2,334 MEDLINE citations.

MEASUREMENTS

Retrieval effectivenesses of the original unexpanded and the alternative expanded queries were compared using 11-point-average precision scores (11-AvgP). These are averages of precision scores obtained at 11 standard recall points.

RESULTS

All three expansion strategies significantly improved the original queries in terms of retrieval effectiveness. Expansion on MeSH alone was equivalent to expansion on both MeSH and the free-text fields. Expansion on the free-text field alone improved the queries significantly less than did the other two strategies. The second part of the study indicated that retrieval-feedback-based expansion yields significant performance improvements independent of the availability of relevant documents for feedback information.

CONCLUSIONS

Retrieval feedback offers a robust procedure for query expansion that is most effective for MEDLINE when applied to the MeSH field.

From chart tracking to workflow management

The current interest in system-wide integration appears to be based on the assumption that an organization, by digitizing information and accepting a common standard for the exchange of such information, will improve the accessibility of this information and automatically experience benefits resulting from its more productive use. We do not dispute this reasoning, but assert that an organization's capacity for effective change is proportional to the understanding of the current structure among its personnel. Our workflow manager is based on the use of a Parameterized Petri Net (PPN) model which can be configured to represent an arbitrarily detailed picture of an organization. The PPN model can be animated to observe the model organization in action, and the results of the animation analyzed. This simulation is a dynamic ongoing process which changes with the system and allows members of the organization to pose "what if" questions as a means of exploring opportunities for change. We present, the "workflow management system" as the natural successor to the tracking program, incorporating modeling, scheduling, reactive planning, performance evaluation, and simulation. This workflow management system is more than adequate for meeting the needs of a paper chart tracking system, and, as the patient record is computerized, will serve as a planning and evaluation tool in converting the paper-based health information system into a computer-based system.

Structured text representations and relevance judgments: an exploratory study

This paper presents results of an exploratory study on using a structured text and query model for analyzing relevance judgments made by users on retrieved texts The structured model moves beyond keyword based text representation and retrieval. In particular it allows texts and queries to be represented by concepts embedded within the structural framework of complex objects. These objects preserves important text-based links between the selected concepts. The current study reveals a tendency for user judged relevance potential to decrease as the structure-based similarity between query and text decreases. This indicates that the structure-based retrieval model has the potential to conduct more precise retrieval than keyword based models. This supports our overall research goal of developing and investigating the structured retrieval model.

An investigation of content representation using text grammars

We extend prior work on a model for natural language text representation and retrieval using a linguistic device called text grammar. We demonstrate the value of this approach in accessing relevant items from a collection of empirical abstracts in a medical domain. The advantage, when compared to traditional keyword retrieval, is that this approach is a significant move towards knowledge representation and retrieval. Text representation in this model includes keywords and their conceptual roles in the text. In particular, it involves extracting TOPIC predicates representing the research issue addressed and DESIGN predicates representing important methodological features of the empirical study. Preliminary experimentation shows that keywords exhibit a variety of text-grammar roles in a text database. Second, as intuitively expected, retrieval using TOPIC predicates identifies a smaller subset of texts than Boolean retrieval does. These empirical results along with the theoretical work indicate that the representation and retrieval strategies proposed have a significant potential. Finally, EMPIRICIST, a prototype system is described. In it the text representation predicates are implemented as a network while retrieval is through constrained-spreading activation strategies.

Quality retrieval of the empirical literature: a structured approach

The extent and growth of medical knowledge is tremendous. As of December 1990, the MEDLINE database had 6.5 million records in its collection, with approximately a third added during the last five years. Despite numerous innovations, retrieval technology has not kept pace with the exploding numbers of authors, articles, journals, books and conferences. A major limiting factor is that the basic mechanisms of retrieval systems almost uniformly rely on keyword representation and searching. These keywords are either assigned to texts perhaps with the assistance of special vocabularies, or appear naturally in these texts. In particular no structural or role information is preserved to connect these keywords to each other. This paper presents an alternative approach wherein role preserving, structured representations are used. This approach has the potential to increase retrieval quality.