Comparison of bone mineral density in both hips

Dual-photon absorptiometry (DPA) was performed on both hips of 40 patients to determine if the calculated bone-mineral density (BMD) of one hip could be used to predict the BMD of the opposite hip. For the Ward triangle, femoral neck, and greater trochanter the correlation coefficients between the BMD of the two hips was .920, .917, and .843, and the standard errors (SE) of the estimate for the linear regression of the left hip on to the right were 0.067, 0.063, and 0.077 g cm-2. The absolute error of predicting one hip from the other was not a function of BMD and thus the relative error increases with lower BMD values. The relative errors were 17%, 8%, and 7% for BMDs of 0.4, 0.8, and 1.0 g cm-2, respectively. The interobserver variability was small, with an r value of .96 and an SE of the estimate value of 0.036 g cm-2. The relative error in the mild-to-moderate osteoporosis categories was 2.5 times the precision of the instrument, indicating that the asymmetry of BMD is due to real differences between hips. Therefore the BMD of one hip cannot be used to predict that of the other with sufficient accuracy to discriminate clinically relevant trends in BMD.     

Translation elongation after assembly of ribosomes on the Cricket paralysis virus internal ribosomal entry site without initiation factors or initiator tRNA

Reconstitution of translation elongation from purified components confirmed that ribosomes that assembled on the Cricket paralysis virus intercistronic internal ribosomal entry site (IRES) without the involvement of initiation factors or initiator tRNA were active in elongation and are, therefore, true initiation complexes. The first elongation cycle occurred without peptide bond formation on 80S ribosomes that did not contain tRNA in the P site. It required elongation factors 1A and 2 and A site-cognate aminoacylated tRNA. Cycloheximide arrested ribosomes on the IRES only after two cycles of elongation, when the first deacylated tRNA reached the E-site after translocation from the A-site.     

Transesophageal echocardiography in diagnosis of infectious endocarditis]

Transthoracic and transesophagal echocardiography (TT EChG and TE EChG) were performed in 43 patients with infectious endocarditis (IE). Sensitivity and specificity of TE EChG in detection of vegetations were higher (92 and 75%, 81 and 50% for TE EChG and TT EChG, respectively). Vegetations and thromboembolism were unrelated. With TE EChG, morphologically verified perforations of valvular cusps were revealed 3 times more frequently than with TT EChG. Along with detection of vegetations and dysfunction of the prosthetic valve, an essential diagnostic marker of IE of the artificial valve is visualization of paraprosthetic fistulas in 2 of 5 patients. Indications for TT and TE EChG and techniques of their performance are described. TT EChG is used in screening for IE. TE EChG is conducted in complications of IE.     

Molecular genetic analysis of Mycobacterium tuberculosis strains spread in different patient groups in St. Petersburg, Russia

Molecular epidemiological features of Mycobacterium tuberculosis strains among different patient groups in Russia have not been studied well. The aim of our study was to compare the genotypes of M. tuberculosis strains circulating among tuberculosis (TB) patients from different groups: homeless, human immunodeficiency virus (HIV)-infected, prisoners, and the general population of St. Petersburg citizens. One hundred and forty-two M. tuberculosis complex isolates from different TB patient groups were studied using the spacer oligonucleotide typing (spoligotyping) method. The majority of the studied M. tuberculosis isolates in all groups belonged to the Beijing family (55% among homeless; 77% among HIV-infected; 60% among the general population; 81% among prisoners). There were no significant differences in the Beijing family prevalence among homeless patients, HIV/TB co-infected patients, and the general population of TB patients. The lowest genetic diversity of the pathogen was detected among imprisoned patients. The results of our study demonstrate that M. tuberculosis strains circulating among patients from high-risk groups are also spread among the general population of St. Petersburg citizens.     

The influence of diabetes on short-term outcome following a prosthetic above-the-knee femoro-popliteal bypass

Objectives

To assess the influence of diabetes mellitus on early morbidity and mortality following a femoro-popliteal bypass.

Methods

Clinical data on patients subjected to a prosthetic above-the-knee femoro-popliteal bypass for atherothrombotic disease over a four-year period in the Durban Metropolitan Vascular Service were culled from a prospectively maintained computerised database. The patients were divided into two groups, diabetic and non-diabetic.

Results

Two hundred and seventeen patient records were analysed; 102 (47%) patients were diabetic and 115 (53%) non-diabetic. The mean age in the two groups was almost similar. Differences noted between the two groups were that there was a higher prevalence of males and cigarette smokers in the non-diabetic group and hypertension among the diabetics. The prevalence of ischaemic heart disease in the two groups was not statistically significant. The majority of patients in both groups presented with critical limb ischaemia.Overall, 208 (96%) of the patients had their procedures performed using loco regional anaesthesia. The incidence of superficial wound infection between the two groups was not statistically significant. Deep infection, which necessitated removal of the graft, and cardiovascular complications were significantly higher in the diabetics. Four patients (3.9%) in the diabetic group and only one (0.9%) in the non-diabetic group died.

Conclusion

Diabetes mellitus significantly increases the incidence of graft sepsis and cardiovascular morbidity in patients undergoing above-the-knee femoro-popliteal bypass.     

Internal initiation of translation of bovine viral diarrhea virus RNA.

Initiation of translation on the bovine viral diarrhea virus (BVDV) internal ribosomal entry site (IRES) was reconstituted in vitro from purified translation components to the stage of 48S ribosomal initiation complex formation. Ribosomal binding and positioning on this mRNA to form a 48S complex did not require the initiation factors eIF4A, eIF4B, or eIF4F, and translation of this mRNA was resistant to inhibition by a trans-dominant eIF4A mutant that inhibited cap-mediated initiation of translation. The BVDV IRES contains elements that are bound independently by ribosomal 40S subunits and by eukaryotic initiation factor (eIF) 3, as well as determinants that mediate direct attachment of 43S ribosomal complexes to the initiation codon.     

Dissociation of eIF1 from the 40S ribosomal subunit is a key step in start codon selection in vivo

Selection of the AUG start codon is a key step in translation initiation requiring hydrolysis of GTP in the eIF2*GTP*Met-tRNA(i)(Met) ternary complex (TC) and subsequent P(i) release from eIF2*GDP*P(i). It is thought that eIF1 prevents recognition of non-AUGs by promoting scanning and blocking P(i) release at non-AUG codons. We show that Sui(-) mutations in Saccharomyces cerevisiae eIF1, which increase initiation at UUG codons, reduce interaction of eIF1 with 40S subunits in vitro and in vivo, and both defects are diminished in cells by overexpressing the mutant proteins. Remarkably, Sui(-) mutation ISQLG(93-97)ASQAA (abbreviated 93-97) accelerates eIF1 dissociation and P(i) release from reconstituted preinitiation complexes (PICs), whereas a hyperaccuracy mutation in eIF1A (that suppresses Sui(-) mutations) decreases the eIF1 off-rate. These findings demonstrate that eIF1 dissociation is a critical step in start codon selection, which is modulated by eIF1A. We also describe Gcd(-) mutations in eIF1 that impair TC loading on 40S subunits or destabilize the multifactor complex containing eIF1, eIF3, eIF5, and TC, showing that eIF1 promotes PIC assembly in vivo beyond its important functions in AUG selection.