Degenerative cerebral alterations in Chinese aged 65 years or older

The brains of 57 consecutive Chinese patients, aged 65 years or above, dying in a regional general hospital, the causes of death of whom were not primarily intracranial, were examined for parameters of degenerative brain disease--reduction in brain weight, ventricular enlargement, neurofibrillary tangles, senile plaques, granulovacuolar degenerations, and ischemic lesions. Semi-quantitative analysis of these morphological changes suggests that, though generally similar to those observed among Caucasians, they occurred much less frequently, and, as regards senile plaques, in smaller numbers. These observations suggest a lower prevalence of "senile" cerebral alterations in Chinese than in Caucasians.     

β-Methyl-15-p-iodophenylpentadecanoic acid metabolism and kinetics in the isolated rat heart

The use of 15-p-iodophenyl--methyl-pentadecanoic acid (Me-IPPA) as an indicator of long chain fatty acid (LCFA) utilization in nuclear medicine studies was evaluated in the isolated, perfused, working rat heart. Time courses of radioctivity (residue curves) were obtained following bolus injections of both Me-IPPA and its straight chain counterpart 15-p-iodophenyl-pentadecanoic acid (IPPA). IPPA kinetics clearly indicated flow independent impairment of fatty acid oxidation caused by the carnitine palmitoyltransferase I inhibitor 2[5(4-chlorophenyl)pentyl]oxirane-2-carboxylate (POCA). In contrast, Me-IPPA kinetics were insenstive to changes in fatty acid oxidation rate and net utilization of long chain fatty acid. Analysis of radiolabeled species in coronary effluent and heart homogenates showed the methylated fatty acid to be readily incorporated into complex lipids but a poor substrate for oxidation. POCA did not significatly alter metabolism of the tracer, suggesting that the tracer is poorly metabolized beyond Me-IPPA-CoA in the oxidative pathway.     

Quantitative evaluation of recall and precision of CAT Crawler,a search engine specialized on retrieval of Critically Appraised Topics

Background

Critically Appraised Topics (CATs) are a useful tool that helps physicians to make clinical decisions as the healthcare moves towards the practice of Evidence-Based Medicine (EBM). The fast growing World Wide Web has provided a place for physicians to share their appraised topics online, but an increasing amount of time is needed to find a particular topic within such a rich repository.

Methods

A web-based application, namely the CAT Crawler, was developed by Singapore's Bioinformatics Institute to allow physicians to adequately access available appraised topics on the Internet. A meta-search engine, as the core component of the application, finds relevant topics following keyword input. The primary objective of the work presented here is to evaluate the quantity and quality of search results obtained from the meta-search engine of the CAT Crawler by comparing them with those obtained from two individual CAT search engines. From the CAT libraries at these two sites, all possible keywords were extracted using a keyword extractor. Of those common to both libraries, ten were randomly chosen for evaluation. All ten were submitted to the two search engines individually, and through the meta-search engine of the CAT Crawler. Search results were evaluated for relevance both by medical amateurs and professionals, and the respective recall and precision were calculated.

Results

While achieving an identical recall, the meta-search engine showed a precision of 77.26% (±14.45) compared to the individual search engines' 52.65% (±12.0) (p < 0.001).

Conclusion

The results demonstrate the validity of the CAT Crawler meta-search engine approach. The improved precision due to inherent filters underlines the practical usefulness of this tool for clinicians.

     

Genetic imbalances in pleomorphic xanthoastrocytoma detected by comparative genomic hybridization and literature review.

Pleomorphic xanthoastrocytoma (PXA) is a rare, low-grade astrocytic tumor found in the central nervous system. Histologically, the tumor is characterized by markedly pleomorphic and lipidized cells. Although most of the patients have a favorable prognosis, a small number of cases undergoing recurrence or progression to anaplastic astrocytoma were reported. Very few genetic studies have been performed on PXA because of its rarity and the pathogenesis of this neoplasm is largely unknown. In order to provide an overview of genetic alterations in PXA, we performed comparative genomic hybridization to identify chromosomal imbalances (DNA gains and losses) in three cases of PXA. Genetic imbalance was detected on at least one chromosome for each case. One case, which revealed multiple genetic alterations, showed a poor prognosis. DNA gain on chromosome 7 and loss on 8p were demonstrated in two of three cases, suggesting that the candidate gene(s) located on these regions may play a role in the development of PXA. Further studies are needed to identify the residing candidate genes that are involved in the tumorigenesis of PXA. In addition, the histopathological features and previous genetic studies on PXA are reviewed.     

An immunohistochemical study of neuronal and glial cell reactions in retinae of rats with experimental glaucoma

Glaucoma is a common disease seen in the eye clinic, but its associated pathological processes, especially the role of glial cells in glaucomatous retinae, are still under debate. The aim of the present work was to study the responses of astrocytes, Müller cells and microglia in retinae of rats with experimental glaucoma. Glaucoma was induced in adult male Wistar rats by cauterizing limbal-derived veins and the changes in glial fibrillary acidic protein (GFAP), OX42, OX18, OX6 and EDI expression were studied by immunohistochemical staining. Neuronal cell viability was studied by immunostaining with the neuronal nuclei (NeuN) antibody. In the experimental glaucomatous eyes, a significant drop in the number of NeuN-positive neurons was observed from 7 days postoperation and beyond in both the ganglion cell layer and inner nuclear layer. The expression of GFAP and OX42 was increased during the first 2 months after operation and reduced in rats at 3 and 4 months. OX6 and OX18 immunoreactivity was induced in some microglia of both glaucomatous and sham-operated control eyes. Possible mechanisms of the reaction of astrocytes, Müller cells and microglia in neuronal degeneration following glaucoma are discussed.     

Reactive hemophagocytic syndrome: a study of 7 fatal cases

Reactive hemophagocytic syndrome is a clinico-pathologic entity characterized by systemic proliferation of non-neoplastic histiocytes showing phagocytosis of hemopoietic cells, resulting in blood cytopenia. It is best known to be associated with virus infection, but other associated diseases have also been implicated. The clinical and pathological findings of 7 fatal cases are described. The syndrome affected both sexes of a wide age range, and all patients had fever. Significant laboratory findings were blood cytopenia, abrupt drop in the blood cell counts, deranged liver function tests and abnormal coagulation profile. The associated diseases were diverse: two patients had bacterial infection; two had peripheral T-cell lymphoma; one had disseminated undifferentiated carcinoma of the ovary; one had both tuberculosis and disseminated nasopharyngeal carcinoma, and one had no obvious underlying disease. It is postulated that lymphokines secreted by lymphoid cells or tumor cells may be responsible for the systemic activation of histiocytes. The differential diagnosis from malignant histiocytosis is discussed.     

Understanding the adaptation of Halobacterium species NRC-1 to its extreme environment through computational analysis of its genome sequence

The genome of the halophilic archaeon Halobacterium sp. NRC-1 and predicted proteome have been analyzed by computational methods and reveal characteristics relevant to life in an extreme environment distinguished by hypersalinity and high solar radiation: (1) The proteome is highly acidic, with a median pI of 4.9 and mostly lacking basic proteins. This characteristic correlates with high surface negative charge, determined through homology modeling, as the major adaptive mechanism of halophilic proteins to function in nearly saturating salinity. (2) Codon usage displays the expected GC bias in the wobble position and is consistent with a highly acidic proteome. (3) Distinct genomic domains of NRC-1 with bacterial character are apparent by whole proteome BLAST analysis, including two gene clusters coding for a bacterial-type aerobic respiratory chain. This result indicates that the capacity of halophiles for aerobic respiration may have been acquired through lateral gene transfer. (4) Two regions of the large chromosome were found with relatively lower GC composition and overrepresentation of IS elements, similar to the minichromosomes. These IS-element-rich regions of the genome may serve to exchange DNA between the three replicons and promote genome evolution. (5) GC-skew analysis showed evidence for the existence of two replication origins in the large chromosome. This finding and the occurrence of multiple chromosomes indicate a dynamic genome organization with eukaryotic character.     

Prosthetic hip joint infection due to Campylobacter fetus.

A case of postoperative prosthetic hip joint infection due to Campylobacter fetus subsp. fetus is described. Difficulties in isolation and antimicrobial susceptibility testing of this organism are discussed.     

Cytokine production in lethal and non-lethal murine malaria

Levels of IFN-gamma, IL-2 and IL-4 were measured in vitro during the course of non-lethal Plasmodium chabaudi adami and lethal P. chabaudi strain 1309 infections in BALB/cByJ mice. Spleen cells from mice infected with the non-lethal Plasmodium had a higher initial response to P. chabaudi antigens than mice infected with P. chabaudi strain 1309, as determined by measuring all three lymphokines. We conclude that both Th1 and Th2 subsets of T helper lymphocytes are activated during P. chabaudi adami infection but that these responses are suppressed in mice infected with the more virulent P. chabaudi strain 1309.