The slow mo mutation reduces pacemaker current and heart rate in adult zebrafish

Genetic studies in zebrafish have focused on embryonic mutations, but many physiological mechanisms continue to mature after embryogenesis. We report here that zebrafish homozygous for the mutation slow mo can be raised to adulthood. In the embryo, the slow mo gene is needed to regulate heart rate, and its mutation causes a reduction in pacemaker current (I(h)) and slowing of heart rate (bradycardia). The homozygous adult slow mo fish continues to manifest bradycardia, without other evident ill effects. Patch-clamp analysis of isolated adult cardiomyocytes reveals that I(h) has chamber-specific properties such that the atrial current density of I(h) is far greater than the ventricular current density of I(h). I(h) is markedly diminished in cardiomyocytes from both chambers of slow mo mutant fish. Thus I(h) continues to be a critical determinant of pacemaker rate even after adult neural and humoral influences have developed. It is clear that zebrafish may be used for genetic dissection of selected physiological mechanisms in the adult.

The aging voice: a review, treatment data and familial and genetic perspectives

This paper will provide a review of aspects of vocal aging within the context of general body aging and describe two data sets related to the aging voice. Data will be presented which document pre- to posttreatment improvement in select voice characteristics (sound pressure level, subglottal air pressure, thyroarytenoid laryngeal muscle activity and voice quality) following application of an intensive voice treatment program (the LSVT) to 3 individuals with aged voice. Additionally, physiological data (forced expiratory volume, visual accommodation, bone density, taste discrimination, white blood count and resting heart rate) and select perceptual (perceived age) and acoustic measures (reflecting both cycle-to-cycle and longer-term intensity and frequency stability) from 67 subjects will be reviewed from the work of Gray and colleagues to document the differential impact of the global aging process across organ systems including the aging voice.

Growth and function of the embryonic heart depend upon the cardiac-specific L-type calcium channel alpha1 subunit

The heart must function from the moment of its embryonic assembly, but the molecular underpinnings of the first heart beat are not known, nor whether function determines form at this early stage. Here, we find by positional cloning that the embryonic lethal island beat (isl) mutation in zebrafish disrupts the alpha1 C L-type calcium channel subunit (C-LTCC). The isl atrium is relatively normal in size, and individual cells contract chaotically, in a pattern resembling atrial fibrillation. The ventricle is completely silent. Unlike another mutation with a silent ventricle, isl fails to acquire the normal number of myocytes. Thus, calcium signaling via C-LTCC can regulate heart growth independently of contraction, and plays distinctive roles in fashioning both form and function of the two developing chambers.

The effect of differing scoring methods for the Tower of London task on developmental patterns of performance

The Tower of London (TOL) task is frequently used to assess executive functioning in both adults and children, although there remains considerable controversy over what it measures and how to score it. In this study we compare two scoring methods and find that correlations between them were high for 7-year-olds (.86), and dropped to a low of .47 for adults. These results demonstrate that the TOL necessarily has different construct validity in adults and children. Second, results of one method (based on errors only) show a developmental trend in performance from middle childhood to adulthood, while the other (based on errors and time) shows a developmental progression from ages 7 to 13, but not between 13-year-olds and young adults. Thus, scoring method influences the resulting developmental model.

Tolterodine versus oxybutynin in the treatment of urge urinary incontinence: a meta-analysis

OBJECTIVE

To compare tolterodine with oxybutynin in treatment of urge incontinence.

STUDY DESIGN

A systematic review, following Cochrane methods, was performed to retrieve results of randomized trials that compared tolterodine with oxybutynin in adults with urge incontinence. Composite point estimates of efficacy (episodes of incontinence per 24-hour period, frequency, and voided volume) and safety (dry mouth, withdrawal, and dose modification) were calculated.

RESULTS

Four studies were included. Both drugs similarly decreased the number of micturitions in a 24-hour period. Oxybutynin was marginally superior to tolterodine in decreasing the number of incontinent episodes in a 24-hour period (weighted mean difference, 0.41; 95% confidence interval [CI], 0.04 to 0.77) and increasing the mean voided volume per micturition (8.24 mL; 95% CI, 14.19 to 3.38). Fewer patients had dry mouth (relative risk, 0.54; 95% CI, 0.48 to 0.61) and withdrew from the study because of side effects (relative risk, 0.63; 95% CI, 0.46 to 0.88) with tolterodine.

CONCLUSIONS

Oxybutynin and tolterodine share a clinically similar efficacy profile (although oxybutynin is statistically superior), but tolterodine is better tolerated and leads to fewer withdrawals as a result of adverse events.

Endoscope reprocessing: taking the mystery out of high-level disinfection

Flexible endoscopes used in otolaryngology are often unable to withstand heat sterilization. An acceptable alternative to heat sterilization for these devices used to examine the aerodigestive tract is high-level disinfection. A review of otolaryngology (ORL) nursing clinical practice indicates that there is confusion regarding the recommended disinfectant solutions to use and the proper manner in which to use them. This article describes a method that is useful in determining the level of risk of infection posed by ORL endoscopy, a description of appropriate levels of disinfection, points to consider for achieving high-level disinfection, and appropriate personal protective measures.

HIRA, the human homologue of yeast Hir1p and Hir2p, is a novel cyclin-cdk2 substrate whose expression blocks S-phase progression

Substrates of cyclin-cdk2 kinases contain two distinct primary sequence motifs: a cyclin-binding RXL motif and one or more phosphoacceptor sites (consensus S/TPXK/R or S/TP). To identify novel cyclin-cdk2 substrates, we searched the database for proteins containing both of these motifs. One such protein is human HIRA, the homologue of two cell cycle-regulated repressors of histone gene expression in Saccharomyces cerevisiae, Hir1p and Hir2p. Here we demonstrate that human HIRA is an in vivo substrate of a cyclin-cdk2 kinase. First, HIRA bound to and was phosphorylated by cyclin A- and E-cdk2 in vitro in an RXL-dependent manner. Second, HIRA was phosphorylated in vivo on two consensus cyclin-cdk2 phosphoacceptor sites and at least one of these, threonine 555, was phosphorylated by cyclin A-cdk2 in vitro. Third, phosphorylation of HIRA in vivo was blocked by cyclin-cdk2 inhibitor p21(cip1). Fourth, HIRA became phosphorylated on threonine 555 in S phase when cyclin-cdk2 kinases are active. Fifth, HIRA was localized preferentially to the nucleus, where active cyclin A- and E-cdk2 are located. Finally, ectopic expression of HIRA in cells caused arrest in S phase and this is consistent with the notion that it is a cyclin-cdk2 substrate that has a role in control of the cell cycle.

HIV and AIDS: an overview

Despite a decrease in deaths due to AIDS in industrialised nations, there is still much confusion surrounding HIV and AIDS. The authors provide an up-to-date overview.

Instillation of allogeneic lung antigen-presenting cells deficient in expression of major histocompatibility complex class I or II antigens have differential effects on local cellular and humoral immunity and on pathology in recipient murine lungs

Recognition of allogeneic major histocompatibility complex (MHC) molecules expressed on donor lung antigen-presenting cells (APCs) by host T lymphocytes is believed to stimulate lung allograft rejection. However, the specific roles of donor MHC molecules in the rejection response is unknown. We report a murine model in which instilling allogeneic lung APCs into recipient lungs induces pathology analogous to acute rejection, and the production of interferon (IFN)-gamma, immunoglobulin (Ig) G2a, and alloantibodies in recipient lungs. Using allogeneic lung APCs (C57BL/6, I-a(b), H-2(b)) deficient in MHC class I, II, or both for instillation into lungs of BALB/c mice (I-a(d), H-2(d)), the purpose of the current study was to determine the specific roles of donor MHC molecules in stimulating local alloimmune responses. The data show that MHC class I or II on donor APCs induced IFN-gamma and IgG2a synthesis locally, though less than that induced by wild-type cells. Both MHC class I and II were required to induce alloantibody production. Instillation of wild-type or class I- or class II-deficient APCs induced comparable pathologic lesions in recipient lungs, and more severe than that induced by MHC-deficient cells. These data show that donor MHC class I and II molecules have differential effects in the stimulation of local alloimmune responses.

Exercise for knee osteoarthritis

Adverse outcomes in knee osteoarthritis include pain, loss of function, and disability. These outcomes can have devastating effects on the quality of life of those suffering from the disease. Treatments have generally targeted pain, assuming that disability would improve as a direct result of improvements in pain. However, there is evidence to suggest that determinants of pain and disability differ. In general, treatments have been more successful at decreasing pain rather than disability. Many of the factors that lead to disability can be improved with exercise. Exercise, both aerobic and strength training, have been examined as treatments for knee osteoarthritis, with considerable variability in the results. The variability between studies may be due to differences in study design, exercise protocols, and participants in the studies. Although there is variability among studies, it is notable that a majority of the studies had a positive effect on pain and or disability. The mechanism of exercise remains unclear and merits future studies to better define a concise, clear exercise protocol that may have the potential for a public health intervention.

Normative data for the F(p) scale of the MMPI-2: implications for clinical and forensic assessment of malingering

Data from several clinical samples and the Minnesota Multiphasic Personality Inventory--2 standardization group are presented to familiarize the reader with response patterns of different groups on a new validity scale designed to assist in the identification of exaggeration or fabrication of psychological disturbance. Sensitivity-specificity analyses are included along with suggestions for use of the F(p) Scale with other validity scales. Cautions about setting single cutoff scores are also discussed.

Human herpesviruses in the cornea

AIMS

To determine the sensitivity and specificity of culture, immunohistochemistry (IHC), the polymerase chain reaction (PCR), and in situ hybridisation (ISH) for detecting herpes simplex virus (HSV-1) in the cornea of patients undergoing penetrating keratoplasty. To compare the incidence of HSV-1 in the cornea with that of varicella zoster virus (VZV), cytomegalovirus (CMV), and Epstein-Barr virus (EBV).

METHODS

The corneas of 110 patients, 52 with a documented history of herpes keratitis (HSK) and 58 with non-herpetic corneal disease, were investigated using IHC, PCR, ISH, and culture.

RESULTS

HSV-1 DNA and antigen were detected in 82% and 74% respectively, of corneas of patients with HSK and in 22% and 15% of corneas of patients with no history of HSK. The sensitivity of PCR and IHC was 82% and 74% with a specificity of 78% and 85%, respectively. HSV-1 DNA and antigen were found more frequently and in increased amounts in corneas of patients with a short interval between their last attack of HSK and surgery. There was a good correlation between PCR and IHC in 71%. HSV-1 was isolated by culture in 2%. Latency associated transcripts were not detected using ISH. Evidence of VZV DNA or antigen was found significantly more frequently in the corneas of patients with a history of HSK (p<0.001). No evidence of EBV or CMV was found in any cornea.

CONCLUSIONS

PCR and IHC are both sensitive for the detection of HSV-1 in the cornea. A combination of PCR and IHC increases the specificity for the diagnosis of HSK to 97%. HSV-1 appears to be slowly removed from the cornea. VZV and HSV-1 may co-infect the cornea.

Developmental changes in blood pressure and the renin-angiotensin system in pony fetuses during the second half of gestation

Blood pressure, heart rate and the plasma concentrations of cortisol and components of the renin-angiotensin system were measured in chronically catheterized Pony mares (n=15) and their fetuses during the second half of gestation (day 153-336 of gestation; term is normally between day 320 and day 340 of gestation). Fetal blood pressure increased towards term with the prepartum surge in plasma cortisol concentration, and there was a correlation between fetal blood pressure and both gestational age (r = 0.88, P < 0.0005) and plasma cortisol concentration (r = 0.88, P < 0.0005). Plasma concentrations of angiotensin-converting enzyme (ACE) and angiotensinogen increased towards term in the fetus; plasma ACE correlated with gestational age (r = 0.83, P < 0.0005), plasma cortisol (r = 0.76, P < 0.005) and blood pressure (r = 0.84, P < 0.0005), whereas plasma concentrations of angiotensinogen correlated with gestational age only (r = 0.80, P <0.0005). Fetal heart rate was correlated inversely with gestational age (r = -0.67, P < 0.05), plasma ACE concentration (r = -0.58, P < 0.05) and plasma angiotensinogen concentration (r = -0.69, P < 0.05). There was a positive correlation between plasma angiotensin II and renin concentrations in the fetuses (r = 0.81, P < 0.05). No gestational changes in plasma angiotensin II or renin concentrations were observed in either the mares or fetuses. Maternal blood pressure, heart rate, plasma ACE and plasma angiotensinogen concentrations also did not change over the period of study. Therefore, in Pony fetuses, maturational changes in the activity of the renin-angiotensin system occur towards term and coincide with the prepartum cortisol surge. These changes in the fetal renin-angiotensin system may be responsible, at least in part, for the observed ontogenic increase in fetal blood pressure.

The temper thing

Examines the tempers and uses of anger by various U.S. presidents, including Andrew Jackson, Theodore Roosevelt, Harry Truman, Richard Nixon, and Lyndon Johnson.

Hyperacute cerebral enhancement: the earliest predictor of hemorrhage by MR imaging?

A test to detect very early hemorrhage in acute cerebral infarct could offer a substantial increase in the safety and success of advanced stroke therapies, particularly when the use of thrombolytic therapies is contemplated. Currently, computed tomography is the standard test for the detection of cerebral hemorrhage but is not a valid predictor of potential areas of hemorrhagic transformation. A technique to evaluate the risk of hemorrhagic transformation in infarcted cerebral tissue has been conducted with contrast-enhanced magnetic resonance imaging in various animal stroke models. Knight demonstrated Gadolinium-DTPA enhancement in the territory of occluded vessels immediately in rats after reperfusion. Gadolinium enhancement was thought to predict areas of hemorrhagic transformation. Yenari and associates demonstrated in rabbit models that contrast-enhanced T1-weighted scans can reveal regions of blood-brain barrier disruption, characterized as hemorrhagic transformation in ischemic tissue. The authors report a clinical example in which hyperacute contrast-enhanced magnetic resonance imaging was the first indication of hemorrhagic transformation within 24 hours of onset of an acute cerebral infarct.

Practice variations in biochemical screening for Down syndrome

The American College of Obstetricians and Gynecologists has recommended that when using biochemical screening for Down syndrome, the cut-off selected for counseling the patient should be consistent with the Down syndrome risk at which the obstetrician routinely offers prenatal cytogenetic diagnosis on the basis of maternal age alone. They also state that multiple marker testing in women over the age of 35 years cannot be recommended for routine Down syndrome screening as an equivalent alternative to offering prenatal cytogenetic diagnosis. The American College of Medical Genetics has issued similar statements. We wanted to determine current practices in regard to these suggestions. A questionnaire was mailed to members of the Society of Perinatal Obstetricians asking: (1) At what maternal age do they offer counseling/amniocentesis? (2) Do they adhere to the Colleges' recommendations with regard to counseling/amniocentesis? (3) Do they change the risk for women age 35 years or over based on serum screening? Results showed that (1) Most members currently identify attaining the age of 35 years as a separate risk factor. (2) There were wide variations in the risk quoted for women 35 years old. (3) Many members used a different risk for their biochemical screening cut-off. (4) 74% of the members would increase the age-related risk for women over 35 years based on serum screening and 49% would decrease this risk based on serum screening. Among members, there were wide variations in the risks quoted; the biochemical screening cut-off used; and the use of serum screening in women over the age of 35 years.

Selective killing of transformed cells by cyclin/cyclin-dependent kinase 2 antagonists

Recent studies identified a short peptide motif that serves as a docking site for cyclin/cyclin-dependent kinase (cdk) 2 complexes. Peptides containing this motif block the phosphorylation of substrates by cyclin A/cdk2 or cyclin E/cdk2. Here we report that cell membrane-permeable forms of such peptides preferentially induced transformed cells to undergo apoptosis relative to nontransformed cells. Deregulation of E2F family transcription factors is a common event during transformation and was sufficient to sensitize cells to the cyclin/cdk2 inhibitory peptides. These results suggest that deregulation of E2F and inhibition of cdk2 are synthetically lethal and provide a rationale for the development of cdk2 antagonists as antineoplastic agents.

A spontaneous corneal change in juvenile Wistar rats

Corneal changes were seen in a shipment of male and female Charles River Wistar (Crl:(WI)BR) albino rats aged 33 days. Seventeen weeks later, varying degrees of corneal roughness were observed ophthalmoscopically in 40 of 43 males and 26 of 29 females. Corneal lesions, described clinically as multiple punctate or particulate opacities, were most often bilateral and located paracentrally. Histologically, lesions were observed in only 21 of 40 males and in 15 of 26 females which had shown clinical changes. The lesions consisted of basophilic particulate material, which occasionally formed linear plaques, lining the basement membrane of the corneal epithelium. Ultrastructurally, irregularly distributed electron-dense deposits, occasionally assuming a concentric laminar appearance, were observed. X-ray microanalysis revealed that the granules consisted predominantly of calcium and phosphorus, with trace amounts of iron, zinc, sodium and aluminium. These mineral deposits in the corneas of Wistar rats were similar to those described in other species. Awareness of this spontaneously occurring disease in Wistar rats is of importance in relation to toxicological investigations in which the cornea may be a target organ.