Cytochrome c mRNA levels decrease in senescent rat heart.

The concentration of mitochondria decrease in the heart as rodents age from maturity to senescence. The reason for this change is not known. One purpose of the present study was to determine if cytochrome c mRNA, representative of proteins of the inner mitochondrial membrane, decreased in the hearts of Fischer 344 rats as they aged from 12 to 24 months. Twenty-two percent less cytochrome c mRNA existed per given quantity of extracted RNA from the heart in 24-month-old rats as compared with the 12-month-old group. No change in the quantities of cardiac -actin mRNA, Ca²⁺/calmodulin protein kinase II mRNA or 18S rRNA was noted between 12- und 24-month-old hearts. Thus, the decrease in cytochrome c mRNA suggests that decreased in mRNAs for proteins of the inner mitochondrial membrane could play some role in the diminished concentration of mitochondria that exists in the senescent heart.     

Alleles of RUNX2/CBFA1 gene are associated with differences in bone mineral density and risk of fracture.

The aim of this study was to determine if DNA polymorphism within runt-related gene 2 (RUNX2)/core binding factor A1 (CBFA1) is related to bone mineral density (BMD). RUNX2 contains a glutamine-alanine repeat where mutations causing cleidocranial dysplasia (CCD) have been observed. Two common variants were detected within the alanine repeat: an 18-bp deletion and a synonymous alanine codon polymorphism with alleles GCA and GCG (noted as A and G alleles, respectively). In addition, rare mutations that may be related to low BMD were observed within the glutamine repeat. In 495 randomly selected women of the Geelong Osteoporosis Study (GOS), the A allele was associated with higher BMD at all sites tested. The effect was maximal at the ultradistal (UD) radius (p = 0.001). In a separate fracture study, the A allele was significantly protective against Colles' fracture in elderly women but not spine and hip fracture. The A allele was associated with increased BMD and was protective against a common form of osteoporotic fracture, suggesting that RUNX2 variants may be related to genetic effects on BMD and osteoporosis.     

Introduction to special section: comorbidity and treatment implications.

This article initiates the special section on comorbidity and treatment implications. The presence of comorbidity is recognized, the multiple meanings of comorbidity are mentioned, and an invitation for much-needed research on comorbidity and related treatment is extended.     

Transmembrane signalling associated with ganglioside-induced CD4 modulation

Ganglioside (GM1) treatment of CD4+ human CEM lymphoma cells stimulated transient phosphoinositide (PI) breakdown, production of inositol phosphates (IP), protein phosphorylation and rapid decrease of CD4 surface expression. A comparison between the actions of GM1 and other agents that affect these signal transduction pathways demonstrated a distinct mechanism for GM1-induced decrease of CD4. GM1 stimulated both phospholipase C activity and protein phosphorylation but had no effect on either cellular cAMP levels or tyrosine kinase activity. Phorbol myristate acetate (PMA) stimulated protein phosphorylation and caused a significant decrease in surface display of CD4. Both of these processes were blocked by pretreating cells with the protein kinase C (PKC) inhibitor H7. These results demonstrate that GM1 stimulates PI turnover and induces a rapid decrease of CD4 surface expression by processes that do not activate adenylate cyclase or tyrosine kinase. They further demonstrate that the mechanism for GM1-induced decrease of CD4 is distinct from the CD4 internalization processes mediated by PKC activity.     

Comparison of the Effectiveness of Two Bowel Programs for CVA Patients

The purpose of the study described in this article was to compare the effectiveness of two bowel training programs for patients who had experienced a cerebrovascular accident (CVA) and to determine the length of time required to establish a regulated program. A quasi-experimental design was used to compare the existing bowel program that incorporated every-other-day digital stimulation (DS) with a program using daily DS. The convenience sample of 48 CVA patients included 23 in the control group who had DS every other day and 25 in the experimental group who had daily DS. Demographic data showed no significant differences between the two groups. The t-test showed that more subjects in the experimental group established regularity; however, the subjects in the control group who did achieve regularity took less time to do it. Subjects with right-side hemiplegia and less mobility required more time to become established. As a result of these findings, the routine protocol for bowel training in this rehabilitation unit has been changed to include daily digital stimulation.     

A comparison between fast and conventional spin-echo in the detection of multiple sclerosis lesions

Long repetition time (TR) spin-echo (SE) with T₂- or proton density weighting is the sequence of choice to detect the brain lesions of multiple sclerosis (MS). Fast spin-echo (FSE) permits the generation of T₂-weighted images with similar contrast to SE but in a fraction of the time. We compared the sensitivity of FSE and SE in the detection of the brain lesions of MS. Six patients with clinically definite MS underwent brain imaging with both dual echo (long TR, long and short echo time (TE) SE and dual echo FSE. The SE and FSE images were first reviewed independently and then compared. A total of 404 lesions was detected on SE and 398 on FSE. Slightly more periventricular lesions were detected using SE than FSE (145 vs 127), whereas more posterior cranial fossa lesions were detected by FSE (77 vs 57). With both SE and FSE the short TE images revealed more lesions than the long echo. These results suggest that FSE could replace SE as the long TR sequence of choice in the investigation of MS.     

A comparative trial of aztreonam versus gentamicin in the treatment of urinary tract infections

A prospective, randomized trial was conducted to compare the efficacy of aztreonam, a monobactam, antibiotic, and gentamicin in the treatment of serious urinary tract infections. Fifty-five patients with a suspected or confirmed infection were randomized, 28 received aztreonam and 27 received gentamicin. Both antibiotics had a high clinical response rate (aztreonam 92%, gentamicin 85%). However, the duration of treatment was significantly shorter (p=0.037, Wilcoxon Rank Sum Test) when aztreonam was used. There were no cases of toxicity with either antibiotic but 5 patients who received gentamicin required dose alteration. Aztreonam is well tolerated and is no less effective than gentamicin in the treatment of urinary tract infections and has advantages in convenience of use and duration of treatment.     

Cardiac tamponade.

Cardiac tamponade is a cardiological emergency requiring prompt treatment in order to avoid a fatal outcome. It can complicate a number of medical conditions and it is important, therefore, that all practitioners are aware of its presentation, diagnosis and management. These are outlined. We suggest that, with certain specific and important exceptions, percutaneous catheter pericardiocentesis is to be recommended in the management of cardiac tamponade. We include a review of 51 consecutive cases treated at our own institution. Catheter pericardiocentesis was successful in 49 (96%) cases and 36 (80%) patients did not require any further intervention. There were no major and only two minor complications which required no additional treatment. We review previous literature concerning percutaneous pericardiocentesis. Using recommended procedures, pericardiocentesis is successful in 90-100% of cases and major complications are rare.     

Localized cerebral proton MR spectroscopy in HIV infection and AIDS.

PURPOSETo document differences in the cerebral proton MR spectra of patients with early and late stages of human immunodeficiency virus (HIV) infection.METHODWe studied the relative N-acetyl-aspartate (NAA) levels by localized proton spectroscopy of the parietooccipital region of the brain in 43 HIV-seropositive patients, including 26 with an acquired immunodeficiency syndrome (AIDS)-defining diagnosis, and in eight control subjects.RESULTSReduced relative NAA levels were shown in those HIV-1-seropositive patients: 1) with AIDS against HIV-1-seropositive patients without AIDS (P < .04); 2) with HIV-1-associated cognitive/motor complex against neurologically healthy patients (P < .007); 3) with encephalopathic changes on MR against those with normal imaging (P < .001); and 4) on follow-up against their results on initial study (P < .03).CONCLUSIONSBy clinical (Centers for Disease Control classification) and radiologic (MR evidence of white-matter disease) criteria indicating late-stage HIV infection, reduced relative levels of NAA have been demonstrated. Spectroscopic abnormalities can be quantitatively tracked with time. This paper demonstrates the clinical use of detecting NAA as a putative in vivo measure of the neuronal loss that has been demonstrated in postmortem studies of patients with AIDS. This neuronal loss, which is believed to underlie the HIV-1-associated cognitive/motor complex, is thought to be attributable directly or indirectly to the presence of HIV in the brain. Proton spectroscopy may serve as a quantitative noninvasive indicator of this aspect of cerebral involvement in HIV disease.