Cluster analysis and display of genome-wide expression patterns

A system of cluster analysis for genome-wide expression data from DNA microarray hybridization is described that uses standard statistical algorithms to arrange genes according to similarity in pattern of gene expression. The output is displayed graphically, conveying the clustering and the underlying expression data simultaneously in a form intuitive for biologists. We have found in the budding yeast Saccharomyces cerevisiae that clustering gene expression data groups together efficiently genes of known similar function, and we find a similar tendency in human data. Thus patterns seen in genome-wide expression experiments can be interpreted as indications of the status of cellular processes. Also, coexpression of genes of known function with poorly characterized or novel genes may provide a simple means of gaining leads to the functions of many genes for which information is not available currently.     

Tuberculosis, a pediatric concern

In vitro excystation studies were done on the metacercarial cysts of Echinostoma trivolvis obtained from the kidneys of naturally infected Rana species tadpoles. Cysts were excysted in an alkaline trypsin-bile salts medium and the percentage of excystation was compared with that from previous studies done on cysts obtained from the kidneys of snails. The percentage of excystation of E. trivolvis metacercariae from tadpole kidneys was similar to that reported for previous studies on cysts obtained from experimentally infected gastropod hosts. The possible role of tadpoles as an agent for the transmission of Echinostoma and echinostomiasis to humans is discussed.     

Combination therapy with interferon alpha and ribavirin for chronic hepatitis C virus infection in thalassaemic patients

Hepatitis C virus (HCV) infection is common in multi-transfused thalassaemic patients, and, in combination with transfusional iron overload, can result in progressive liver disease. Therapy with interferon-alpha causes a sustained loss of HCV in only 15-25% of patients, and there is as yet no established effective therapy for those who fail to respond. We have conducted a pilot study of combination anti-viral therapy for patients who failed to respond, or relapsed after an initial response to single-agent interferon-alpha. Patients were treated for 6 months with interferon-alpha 2b, given subcutaneously three mega units thrice weekly, together with ribavirin, orally 1 g daily. 11 patients were enrolled, their median age was 24.9 years. 8/10 evaluable patients had cirrhosis on biopsy, five were infected with HCV type 1 and all but one had initial HCV RNA titres > 10(6) genomes/ml. Five patients (45.5%) had a sustained virological response with loss of serum HCV RNA for > 6 months after finishing therapy. There was no clear association between response to therapy and age, histology, HCV genotype, or HCV RNA titre. Transfusion requirements were significantly increased during the treatment phase, probably due to ribavirin-induced haemolysis, and this necessitated intensification of iron chelation therapy. Serum ferritin levels decreased significantly in those who responded. These results suggest that combination therapy is potent in clearing HCV infection, and may provide effective second-line therapy for thalassaemic patients who have failed to respond to interferon-alpha monotherapy.     

Systemic methotrexate therapy versus laparoscopic salpingostomy in tubal pregnancy. Part II. Patient preferences for systemic methotrexate

OBJECTIVE: To investigate patient preferences for systemic methotrexate therapy relative to laparoscopic salpingostomy in the treatment of tubal pregnancy. DESIGN: Preference assessment in controlled clinical study. SETTING: Four hospitals and one infertility clinic. PATIENT(S): Forty patients who had been treated for tubal pregnancy and 40 nonpregnant controls. INTERVENTION(S): Preference for methotrexate therapy relative to salpingostomy was established during an interview. Two scenarios were offered for methotrexate therapy: one with and one without preceding diagnostic laparoscopy. Hypothetical tubal patency rates after methotrexate therapy were varied in both scenarios until patients switched in their initial preference. MAIN OUTCOME MEASURE(S): Preference for systemic methotrexate therapy. RESULT(S): Only a few patients switched in their initial preference when the tubal patency rate after systemic methotrexate therapy was varied. Most preferred methotrexate therapy without an increase in the tubal patency rate in a scenario without preceding diagnostic laparoscopy. A small group never opted for methotrexate therapy even when it would guarantee a 100% tubal patency rate. CONCLUSION(S): Systemic methotrexate therapy would be preferred by most patients as part of a completely nonsurgical management strategy. Tubal patency was a decisive factor for treatment preference in a minority of patients only.     

Anatomy of the normal brachial plexus revealed by sonography and the role of sonographic guidance in anesthesia of the brachial plexus

The complete amino acid sequence of [2Fe-2S] ferredoxin from Physalis alkekengi var. francheti has been determined by automated Edman degradation of the entire Cm-protein and of the peptides obtained by trypsin and endoproteinase Asp-N digestions. This ferredoxin exhibited ten, ten, and nine differences respectively in the amino acid sequence, when compared with the ferredoxins of Datura stramonium, D. metel, and D. arborea, but 21-28 differences for other angiosperms, and 34-37 differences for fern and horsetails. These results are in harmony with the taxonomic position for these plants.     

Prk, a cytokine-inducible human protein serine/threonine kinase whose expression appears to be down-regulated in lung carcinomas

We have cloned and characterized a putative protein serine/threonine kinase termed prk through a combination of polymerase chain reaction and conventional cDNA library screening approaches. There are apparently two distinct domains within prk protein deduced from its nucleotide sequences. The amino-terminal portion has the feature of the catalytic domain of a serine/threonine kinase and shows strong homology to mouse fnk and other polo family kinases including mouse snk, human and murine plk, Drosophila polo, and yeast Cdc5. The carboxyl-terminal portion, presumably the regulatory domain, shares extensive homology to mouse fnk. Northern blotting analyses reveal that prk expression is restricted to a very limited number of tissues with placenta, ovaries, and lung containing detectable amounts of prk mRNA. prk mRNA expression is also detected at a low level in the megakaryocytic cell line Dami, MO7e, and three brain glioma cell lines. In addition, refeeding of serum-deprived MO7e, Dami, and K562 cells of hematopoietic origin and GMOO637D of lung fibroblasts rapidly activates prk mRNA expression with its peak induction around 2 h after serum addition. prk gene activation by the serum requires no new protein synthesis. The recombinant cytokines such as interleukin-3 and thrombopoietin also activate prk mRNA expression in MO7e cells. Furthermore, a survey of RNAs isolated from the tumor and the uninvolved tissues from 18 lung cancer patients reveals that prk mRNA expression is significantly down-regulated in tumor tissues. Southern blotting analysis indicates that the prk gene is present in a single copy in the genome of tumors and normal cells. Taken together, these results suggest that prk expression may be restricted to proliferating cells and involved in the regulation of cell cycle progression. The molecular cloning of prk cDNA will facilitate the study of its biological role as well as its potential role in tumorigenesis.     

Ribosomes from Xenopus laevis eggs and embryos in a cell-free protein-synthesizing system: translational regulation

Three types of ribosomal preparations from Xenopus laevis eggs and embryos were tested in a cell-free system to study possible translational regulation of protein synthesis as mediated by the ribosome during early amphibian development: type 1, a crude high-speed sediment, mainly containing monoribosomes completely dissociable by 0.5 M KC1; type II, ribosomes washed with 0.5 M KC1; and type III, ribosomes treated with puromycin - 0.5 M KC1. All three types showed an active response to the addition of poly[U]. Type III was found to be the most active: levels of incorporation of 30 phenylalanine residues/ribosome were reached. In all three cases ribosomes prepared from unfertilized eggs were 30-40% less active in vitro than those from cleavage and gastrula stages.     

Thermal expansion modular femoral head extractor for revision total hip arthroplasty

Removal of a prosthetic modular femoral head is sometimes desirable during revision hip arthroplasty. A femoral head extractor was designed to heat and expand the prosthetic femoral head, apply a gentle distraction load, and remove the femoral head without injury to the femoral neck, taper, or bone-prosthesis interface. The device was used clinically in six hip revision cases. In five hips with cobalt-chrome heads and titanium alloy tapers, femoral heads were removed successfully; femoral fixation was maintained and femoral components were not visibly damaged. In the sixth case, the female portion of the taper junction was contained in a long femoral head sleeve. Heating the ball did not adequately expand the sleeve to allow easy ball removal.     

Inner ear perfusion and the role of round window patency

OBJECTIVE: To report two cases of seizures associated with the use of muromonab-CD3. CASE SUMMARY: Two uremic cadaveric kidney transplant recipients had developed generalized seizures following administration of muromonab-CD3 within the first 2 days after transplantation. Seizures were treated successfully with intravenous phenytoin, and muromonab-CD3 administration was discontinued. DISCUSSION: The overall frequency of seizures during muromonab-CD3 administration is 6%. Uremia in patients in the early posttransplant period appears to predispose them to seizures. Seizures that happened to our two uremic patients after transplant suggest that they had been induced by muromonab-CD3 administration. The mechanism of how this could have induced seizures is unknown. CONCLUSIONS: Prophylactic muromonab-CD3 should be used carefully in uremic kidney transplant recipients following surgery. If therapy with muromonab-CD3 is necessary early hemodialysis should be considered in an effort to lower the risk of seizures.