Testosterone-mediated neuroprotection through the androgen receptor in human primary neurons

Estrogen is an active neuroprotectant and is presently investigated as a potential therapy against Alzheimer's disease for women. To determine if male hormones could also be neuroprotective, we investigated the effect of testosterone, methyltestosterone, and epitestosterone at physiological concentrations on primary cultures of human neurons induced to undergo apoptosis by serum deprivation. Serum deprivation significantly induces neuronal apoptosis in a protracted fashion. As expected, physiological concentrations of 17-beta-estradiol and transcriptionally inactive 17-alpha-estradiol protect neurons against apoptosis. Similar to 17-beta-estradiol, physiological concentrations of testosterone are also neuroprotective. Androgen receptors are present at 8 +/- 2 fmol/mg protein in the neuron cultures. The non-aromatizable androgen, mibolerone, is also neuroprotective and aromatase inhibitor, 4-androsten-4-OL-3,17-dione, does not prevent testosterone-mediated neuroprotection. In contrast, anti-androgen, flutamide, eliminates testosterone-mediated neuroprotection. Testosterone analog, methyltestosterone, showed androgen receptor-dependent neuroprotection that was delayed in time indicating that a metabolite may be the active agent. The endogenous anti-androgen, epitestosterone, also showed a slight neuroprotective effect but not through the androgen receptor. These results indicate that androgens induce neuroprotection directly through the androgen receptor. These data suggest that androgens may also be of therapeutic value against Alzheimer's disease in aging males.

Obstetric admissions to the intensive care unit

OBJECTIVE

To determine whether obstetric admissions to the intensive care unit (ICU) are useful quality-assurance indicators.

METHODS

We analyzed retrospectively obstetric ICU admissions at two tertiary care centers from 1991 to 1997.

RESULTS

The 131 obstetric admissions represented 0.3% of all deliveries. The majority (78%) of women were admitted to the ICU postpartum. Obstetric hemorrhage (26%) and hypertension (21%) were the two most common reasons for admission. Together with cardiac disease, respiratory disorders, and infection, they accounted for more than 80% of all admissions. Preexisting medical conditions were present in 38% of all admissions. The median Acute Physiology and Chronic Health Evaluation II score was 8.5. The predicted mortality rate for the group was 10.0%, and the actual mortality rate was 2.3%.

CONCLUSION

The most common precipitants of ICU admission were obstetric hemorrhage and uncontrolled hypertension. Improved management strategies for these problems may significantly reduce major maternal morbidity.

Modulation of retinoic acid receptor function alters the growth inhibitory response of oral SCC cells to retinoids

Retinoids have been shown to inhibit the growth of many human tumor cells including breast, ovarian and squamous cell carcinoma (SCC). While the exact mechanism of retinoid mediated growth suppression is not known, a role for the retinoic acid receptors (RARs) and retinoid X receptors (RXRs) has been established in both the breast and ovarian tumor cell models. We set out to determine if modulation of RAR/RXR function would alter the retinoid sensitivity of oral SCC cells. We found that the growth of SCC cells was significantly inhibited by treatment with either all-trans-retinoic acid (trans-RA) or the synthetic, conformationally restricted RARgamma selective retinoids MM11254 and MM11389. In order to demonstrate a role for RAR/RXR function in this process, stable oral SCC cell clones constitutively overexpressing the dominant negative mutant RARbeta2 (R269Q) were prepared and shown to exhibit reduced RAR/RXR transcriptional transactivation activity. We found that oral SCC cells exhibiting reduced RAR/RXR function became resistant to growth inhibition by all-trans-RA, MM11254 and MM11389. Likewise, treatment of oral SCC cells with the RARgamma antagonist MM11253 was found to block the ability of MM11254 and MM11389 to inhibit SCC cell growth. Thus, modulation of RAR function through the use of RAR-gamma selective agonists, an RAR-gamma selective antagonist or a pan-RAR dominant negative mutant significantly alters the growth inhibitory response of oral SCC cells to retinoids.

Image-guided radiosurgery for the spine and pancreas

A robotic image-guided radiosurgical system has been modified to treat extra-cranial sites using implanted fiducials and skeletal landmarks to locate the treatment targets. The system has been used to treat an artero-venous malformation in the cervical spine, a recurrent schwannoma of the thoracic spine, a metastatic adenocarcinoma of the lumbar spine, and three pancreatic cancers. During each treatment, the image guidance system monitored the position of the target site and relayed the target coordinates to the beam-pointing system at discrete intervals. The pointing system then dynamically aligned the therapy beam with the lesion, automatically compensating for shifts in target position. Breathing-related motion of the pancreas lesions was managed by coordinating beam gating with breath-holding by the patient. The system maintained alignment with the spine lesions to within +/- 0.2 mm on average, and to within +/- 1 mm for the pancreatic tumors. This experience has demonstrated the feasibility of using image-guided robotic radiosurgery outside the cranium.

Cage size and flight speed of the tobacco hawkmoth Manduca sexta

Flight speeds and behaviors of the sphinx moth Manduca sexta were recorded in chambers of four different sizes (0.57, 8.5, 44 and 447 m3). Mean horizontal speed increased linearly with the cube root of chamber volume from 0.57 m s-1 in the smallest chamber to 3.4 m s-1 in the largest. The maximum horizontal speed observed was 5.3 m s-1 in the largest chamber. Speeds decreased linearly with the logarithm of hawkmoth proximity to the wall. In a tunnel chamber (the third largest), moths often flew in a scalloped-shaped path. At the top of the scallop, they glided for 1­5 wing beats. In the largest chamber, moths could be recorded flying at angles other than horizontal (0 °). At flight angles greater or less than 0 °, mean speed decreased linearly with angle until ±40 °. At greater angles, speeds remained between 1 and 2 m s-1. Moths also flew closer to the wall at flight angles deviating from the horizontal. An allometric analysis of the flight speeds of insects and birds suggests that M. sexta may be able to fly at 7­10 m s-1. We conclude that chamber size limits the flight speed and modifies the flight behavior of the tobacco hawkmoth.

Daily low-dose carboplatin as a radiation sensitizer for newly diagnosed malignant glioma

Surgical resection followed by local field radiotherapy is currently our most effective approach to treatment for most patients with malignant glioma. Carboplatin chemotherapy has direct cytotoxic effects on glioma cells and acts as a radiation sensitizer to enhance cell killing. Its demonstrated efficacy as a sensitizer in other solid tumors led to this clinical trial of carboplatin as a radiation sensitizer in the treatment of newly diagnosed glioblastoma multiforme (GBM) and anaplastic astrocytoma (AA). Fourteen patients (nine GBM and five AA) were treated with daily low-dose carboplatin 25 mg/m2 intravenously within 2 h of their fractionated radiotherapy to a total dose of 600 mg/m2. No significant toxicities attributable to this combined therapy were observed. All patients have progressed, with median time to progression of 16 weeks. Eleven patients have died, with median survival of 38 weeks for the entire cohort. Although this regimen appeared safe, there was no benefit in survival time compared to historical patients treated with radiotherapy. The limitations and future potential for the strategy of radiation sensitization are discussed.

Effect of rapamycin and interleukin-2 on regulatory CD4+CD25+Foxp3+ T cells in mice after allogenic corneal transplantation

BACKGROUND

We explored the effect of rapamycin (RAPA) and interleukin (IL)-2 on regulatory CD4(+)CD25(+)Foxp3(+) T cells (Treg) in recipient mice after allogenic corneal transplantation and analyzed its correlation with graft outcome.

METHODS

Allogenic corneal transplantation was performed using C57/BL6 mice as donors and Balb/c mice as recipients. RAPA, IL-2, and RAPA + IL-2 (mixed group) were administered to recipient mice, with three dosages for each therapeutic protocol. The graft status was assessed twice per week. The percentage of CD4(+)CD25(+)Foxp3(+) Treg in the peripheral blood, spleen, and draining lymph nodes was analyzed. The expression of Foxp3 mRNA in grafts was tested, and the concentration of IL-10 and transforming growth factor (TGF)-β1 in serum and aqueous humor was measured.

RESULTS

The lowest scores of graft neovascularization and opacity were mainly found in mixed groups. The percentage of CD4(+)CD25(+)Foxp3(+) Tregs in blood was increased significantly in mice treated with either high-dose RAPA or high-dose IL-2, and a synergistic effect was found in mixed high-dose group. So were the Tregs in either spleen or draining lymph nodes. However, such effects were weakened with decreased dosage. Foxp3 gene expression in grafts was elevated significantly in the recipients treated with median dosage of RAPA, IL-2, and mixed agents. The concentration of IL-10 in serum and aqueous humor was increased significantly in mice with mixed- high-dose treatment. Mixed treatments also enhanced TGF-β1 level in serum and aqueous humor, except those receiving low dosage.

CONCLUSION

In vivo administration of RAPA prohibited graft rejection after allogenic penetrating keratoplasty through expansion of CD4(+)CD25(+)Foxp3(+) Tregs. Simultaneous treatment of IL-2 enabled further elevation of Tregs. However, the synergistic effect was dosage-dependent, being the most potent at high dosage. The protocol may be beneficial to induce transplantation tolerance.

In vivo confocal microscopy of early corneal epithelial recovery in patients with chemical injury

PURPOSE

To investigate the early recovery of corneal epithelium in patients with chemical injuries by the application of in vivo laser scanning confocal microscopy (LSCM).

METHODS

LSCM was performed on 26 eyes of 18 consecutive patients at 1, 2, and 3 months post injury. The morphology of central corneal epithelium and limbus was evaluated. Analysis was performed to compare the densities of corneal apical surface cells (ASCs) and basal epithelial cells (BECs) among different injury severity and time points after injury. The comparisons were also made on inflammatory cells (ICs) and dendritic cells (DCs) infiltrating at the limbus. Moreover, the presence rate of palisades of Vogt (POV) was analyzed at 3 months post injury.

RESULTS

Corneal re-epithelialization was found within 3 months post injury in all eyes, except that persistent epithelium defect was identified in grade IV injured eyes even at 3 months after injury. The injury severity had a significantly negative correlation with the densities of ASCs. However, it had no relationship with the densities of BECs. The density of ICs at the limbus decreased significantly with the prolongation of follow-up, except in the grade I injured eyes. The presence rate of POV also had a significantly negative correlation with injury severity.

CONCLUSION

Epithelial recovery after chemical injury varied in cellular morphology and the densities of ASCs among eyes with different injury severity. The presence rates of POV decreased with the aggravation of injury. LSCM is a feasible method for observing the early recovery of corneal epithelium in patients with chemical injuries.

Nanoengineered injectable hydrogels derived from layered double hydroxides and alginate for sustained release of protein therapeutics in tissue engineering applications

Chronic Kidney Disease (CKD) which involves gradual loss of kidney function is characterized by low levels of a glycoprotein called Erythropoietin (EPO) that leads to red blood cell  deficiency and anemia. Recombinant human EPO (rhEPO) injections that are administered intravenously or subcutaneously is the current gold standard for treating CKD. The rhEPO injections have very short half-lives and thus demands frequent administration with a risk of high endogenous EPO levels leading to severe side effects that could prove fatal. To this effect, this work provides a novel approach of using lamellar inorganic solids with a brucite-like structure for controlling the release of protein therapeutics such as rhEPO in injectable hydrogels. The nanoengineered injectable system was formulated by incorporating two-dimensional layered double hydroxide (LDH) clay materials with a high surface area into alginate hydrogels for sustained delivery. The inclusion of LDH in the hydrogel network not only improved the mechanical properties of the hydrogels (5-30 times that of alginate hydrogel) but also exhibited a high binding affinity to proteins without altering their bioactivity and conformation. Furthermore, the nanoengineered injectable hydrogels (INHs) demonstrated quick gelation, injectability, and excellent adhesion properties on human skin. The in vitro release test of EPO from conventional alginate hydrogels (Alg-Gel) showed 86% EPO release within 108 h while INHs showed greater control over the initial burst and released only 24% of EPO in the same incubation time. INH-based ink was successfully used for 3D printing, resulting in scaffolds with good shape fidelity and stability in cell culture media. Controlled release of EPO from INHs facilitated superior angiogenic potential in ovo (chick chorioallantoic membrane) compared to Alg-Gel. When subcutaneously implanted in albino mice, the INHs formed a stable gel in vivo without inducing any adverse effects. The results suggest that the proposed INHs in this study can be utilized as a minimally invasive injectable platform or as 3D printed patches for the delivery of protein therapeutics to facilitate tissue regeneration.

A novel metalloproteinase present in freshly isolated rat glomeruli

We have utilized [3H] gelatin to document high activity of a metalloproteinase present in freshly isolated rat glomeruli. [3H] gelatin degradation by glomeruli was markedly inhibited by EDTA (10 mM: -89 +/- 2.3%) and o-phenanthroline (2 mM: -72 +/- 0.1%), inhibitors of metalloproteinases. No significant inhibition of [3H]gelatin degradation was observed with inhibitors of serine or cysteine proteinases. Most (greater than 80%) of the glomerular metalloproteinase (GLOMP) activity was associated with the pellet after centrifugation of sonicated glomeruli at 100,000 g for 90 min. The pH optimum for gelatin degradation by sonicated glomeruli was approximately pH 8.5. Sodium dodecyl sulfate substrate (gelatin)-polyacrylamide gel electrophoresis revealed a single major band of EDTA-inhibitable gelatin-degrading activity with a molecular mass of approximately 116-125 kDa. The GLOMP activity was not inhibited by tissue inhibitors of metalloproteinases, did not appear to be latent, and was not activated by organomercurial activators of several latent metalloproteinases. GLOMP activity was increased 3.4-fold after incubation with trypsin (20 micrograms/ml, 25 min, 22 degrees C). These data indicate that GLOMP is distinct from the previously described matrix metalloproteinases, as well as other metalloproteinases present in the kidney, including the gelatinase secreted by cultured mesangial cells, Meprin, and endopeptidase 24.11 (enkephalinase, EC 3.4.24.11).

Does a history of postoperative ileus predispose to recurrent ileus after multistage ileal pouch-anal anastomosis?

BACKGROUND

Although postoperative ileus (POI) is a common complication after major abdominal colorectal surgery, it is unknown whether a history of POI predisposes to recurrent POI in subsequent surgeries. In the present retrospective case-control study, conducted at the colorectal surgery division of a tertiary care center, we attempted to identify factors that may predict recurrent POI in ulcerative colitis (UC) patients undergoing three-stage ileal pouch-anal anastomosis (IPAA).

METHODS

Charts of UC patients undergoing three-stage IPAA were reviewed. All patients received a standardized accelerated postoperative care pathway. Patients were assigned to one of 3 categories: Group A patients did not have POI after either initial subtotal colectomy (STC) or subsequent IPAA, Group B patients developed POI only after initial STC, and Group C patients developed POI after both STC and IPAA.

RESULTS

The study group consisted of 91 patients. There were 71 (78 %) patients in Group A, 14 (15 %) patients in Group B, and 6 (7 %) patients in group C. There was no significant difference in any demographic or clinical features among patients that developed no POI, those that developed POI only after STC, and those that developed POI after both STC and IPAA.

CONCLUSIONS

POI is difficult to predict after first- and second-stage IPAA. Clinical factors and a history of POI from first-stage IPAA do not predict POI after second-stage IPAA. Patients with a history of POI after STC do not have an increased risk of developing recurrent POI.

Continuing risk for hepatitis B virus transmission among Southeast Asian infants in Louisiana

OBJECTIVE

Implementation and evaluation of a hepatitis B vaccination program for Southeast Asian infants in Louisiana.

METHODS

A baseline seroprevalence survey of hepatitis B virus (HBV) infection in US-born Southeast Asian children was conducted in 1991 before the implementation of a vaccination program. Hepatitis B vaccination and postvaccination serologic testing of survey participants 10 years of age and younger was performed. Eighteen months after the hepatitis B vaccine was integrated into infant immunization schedules in July 1993, a vaccination coverage survey was performed.

RESULTS

Baseline serologic testing was conducted on 96% of persons from 225 randomly selected households in a Southeast Asian community in Louisiana. Of 676 US-born children, 28 (4.1%) had chronic HBV infection; 61% of children with chronic HBV infection were born to hepatitis B surface antigen (HBsAg)-negative women. Among children born to HBsAg-negative women, the prevalence of chronic HBV infection increased with age, reaching 7.3% for children 13 to 16 years of age. Children born to HBsAg-negative women and living with carriers were 5.4 times more likely to have evidence of HBV infection than were children who did not live with carriers. Before the survey, only one child had received three doses of hepatitis B vaccine. In July 1993, 43% of Southeast Asian infants 9 to 18 months of age born in Louisiana had received three doses of hepatitis B vaccine. Infants who received immunizations from private providers were more likely to be fully vaccinated than were infants who received services from public sector clinics (prevalence ratio, 2.1; 95% confidence interval, 1.4, 3.1).

CONCLUSIONS

HBV transmission occurs throughout childhood in US-born Southeast Asian children, and the prevalence of chronic HBV infection approaches that of the country of origin. Few US-born Southeast Asian children have received hepatitis B vaccine. Because of the high rates of early childhood HBV transmission and the high risk of chronic infection in Asian and Pacific Islander communities, prevention efforts should be enhanced to ensure that all Asian and Pacific Islander infants receive hepatitis B vaccine in the first 12 months of life and that older children are vaccinated.

Involvement of C-Abl tyrosine kinase in lipopolysaccharide-induced macrophage activation

LPS endotoxin-induced macrophage activation is recognized to be important in both nonspecific immunity and endotoxin-induced sepsis when excessive macrophage stimulation occurs. In this study, we showed that reduction of c-Abl in macrophages prevented LPS-induced growth arrest, nitric oxide production and TNF-alpha secretion by ANA-1 macrophages. These cells continued to grow but later underwent apoptosis. Reduction of c-Abl in these cells led to reduced c-Abl kinase activity associated with Ran, which recently has been shown to be an LPS-responsive gene product. Our data suggest that c-Abl tyrosine kinase is one of the intermediates downstream of the initial signal transduction event related to activation of macrophages by LPS.

Skill shortages in health: innovative solutions using vocational education and training

INTRODUCTION

This article reports findings of a project funded by the Australian National Council for Vocational Education Research. The project explores solutions to current and projected skills shortages within the health and community services sector, from a vocational education and training perspective. Its purpose is to locate, analyse and disseminate information about innovative models of health training and service delivery that have been developed in response to skill shortages.

METHODS

The article begins with a brief overview of Australian statistics and literature on the structure of the national health workforce and perceived skill shortages. The impact of location (state and rurality), demographics of the workforce, and other relevant factors, on health skill shortages is examined. Drawing on a synthesis of the Australian and international literature on innovative and effective models for addressing health skill shortages and nominations by key stakeholders within the health sector, over 70 models were identified. The models represent a mixture of innovative service delivery models and training solutions from Australia, as well as international examples that could be transposed to the Australian context. They include the skill ecosystem approach facilitated by the Australian National Training Authority Skill Ecosystem Project. Models were selected to represent diversity in terms of the nature of skill shortage addressed, barriers overcome in development of the model, healthcare specialisations, and different customer groups.

RESULTS

Key barriers to the development of innovative solutions to skills shortages identified were: policy that is not sufficiently flexible to accommodate changing workplace needs; unwillingness to risk take in order to develop new models; delays in gaining endorsement/accreditation; current vocational education and training (VET) monitoring and reporting systems; issues related to working in partnership, including different cultures, ways of operating, priorities and timelines; workplace culture that is resistant to change; and organisational boundaries. For training-only models, additional barriers were: technology; low educational levels of trainees; lack of health professionals to provide training and/or supervision; and cost of training. Key enhancers for the development of models were identified as: commitment by all partners and co-location of partners; or effective communication channels. Key enhancers for model effectiveness were: first considering work tasks, competencies and job (re)design; high profile of the model within the community; community-based models; cultural fit; and evidence of direct link between skills development and employment, for example VET trained aged care workers upskilling for other health jobs. For training only models, additional enhancers were flexibility of partners in accommodating needs of trainees; low training costs; experienced clinical supervisors; and the provision of professional development to trainers.

CONCLUSIONS

There needs to be a balance between short-term solutions to current skill shortages (training only), and medium to longer term solutions (job redesign, holistic approaches) that also address projected skills shortages. Models that focus on addressing skills shortages in aged care can provide a broad pathway to careers in health. Characteristics of models likely to be effective in addressing skill shortages are: responsibility for addressing skills shortage is shared between the health sector, education and training organisations and government, with employers taking a proactive role; the training component is complemented by a focus on retention of workers; models are either targeted at existing employees or identify a target group(s) who may not otherwise have considered a career in health.