A Rational Approach to Estimating the Surgical Demand Elasticity Needed to Guide Manpower Reallocation during Contagious Outbreaks

Background

Emerging infectious diseases continue to pose serious threats to global public health. So far, however, few published study has addressed the need for manpower reallocation needed in hospitals when such a serious contagious outbreak occurs.

Aim

To quantify the demand elasticity of the major surgery types in order to guide future manpower reallocation during contagious outbreaks.

Materials and Methods

Based on a nationwide research database in Taiwan, we extracted the monthly volumes of major surgery types for the period 1998–2003, which covered the SARS period, in order to carry out a time series analysis. The demand elasticity of each surgery type was then estimated by autoregressive integrated moving average (ARIMA) analysis.

Results

During the study period, the surgical volumes of most selected surgery types either increased or remained steady. We categorized these surgery types into low-, moderate- and high-elastic groups according to their demand elasticity. Appendectomy, ‘open reduction of fracture with internal fixation’ and ‘free skin graft’ were in the low demand elasticity group. Transurethral prostatectomy and extracorporeal shockwave lithotripsy (ESWL) were in the high demand elasticity group. The manpower of the departments carrying out the surgeries with low demand elasticity should be maintained during outbreaks. In contrast, departments in charge of surgeries mainly with high demand elasticity, like urology departments, may be in a position to have part of their staff reallocated.

Conclusions

Taking advantage of the demand variation during the SARS period in 2003, we adopted the concept of demand elasticity and used a time series approach to figure out an effective index of demand elasticity for various types of surgery that could be used as a rational reference to carry out manpower reallocation during contagious outbreak situations.     

Tetrahydroindolizinone NK1 antagonists

A new class of potent NK₁ receptor antagonists with a tetrahydroindolizinone core has been identified. This series of compounds demonstrated improved functional activities as compared to previously identified 5,5-fused pyrrolidine lead structures. SAR at the 7-position of the tetrahydroindolizinone core is discussed in detail. A number of compounds displayed high NK₁ receptor occupancy at both 1 h and 24 h in a gerbil foot tapping model. Compound 40 has high NK₁ binding affinity, good selectivity for other NK receptors and promising in vivo properties. It also has clean P₄₅₀ inhibition and hPXR induction profiles.     

Invasion of the Lyme Disease Vector <Emphasis Type="Italic">Ixodes scapularis</Emphasis>: Implications for <Emphasis Type="Italic">Borrelia burgdorferi</Emphasis> Endemicity

Lyme disease risk is increasing in the United States due in part to the spread of blacklegged ticks Ixodes scapularis, the principal vector of the spirochetal pathogen Borrelia burgdorferi. A 5-year study was undertaken to investigate hypothesized coinvasion of I. scapularis and B. burgdorferi in Lower Michigan. We tracked the spatial and temporal dynamics of the tick and spirochete using mammal, bird, and vegetation drag sampling at eight field sites along coastal and inland transects originating in a zone of recent I. scapularis establishment. We document northward invasion of these ticks along Michigan’s west coast during the study period; this pattern was most evident in ticks removed from rodents. B. burgdorferi infection prevalences in I. scapularis sampled from vegetation in the invasion zone were 9.3% and 36.6% in nymphs and adults, respectively, with the majority of infection (95.1%) found at the most endemic site. There was no evidence of I. scapularis invasion along the inland transect; however, low-prevalence B. burgdorferi infection was detected in other tick species and in wildlife at inland sites, and at northern coastal sites in years before the arrival of I. scapularis. These infections suggest that cryptic B. burgdorferi transmission by other vector-competent tick species is occurring in the absence of I. scapularis. Other Borrelia spirochetes, including those that group with B. miyamotoi and B. andersonii, were present at a low prevalence within invading ticks and local wildlife. Reports of Lyme disease have increased significantly in the invasion zone in recent years. This rapid blacklegged tick invasion—measurable within 5 years—in combination with cryptic pathogen maintenance suggests a complex ecology of Lyme disease emergence in which wildlife sentinels can provide an early warning of disease emergence.     

Treatment with apolipoprotein A-1 mimetic peptide reduces lupus-like manifestations in a murine lupus model of accelerated atherosclerosis

Introduction

The purpose of this study was to evaluate the effects of L-4F, an apolipoprotein A-1 mimetic peptide, alone or with pravastatin, in apoE^-/-Fas^-/-C57BL/6 mice that spontaneously develop immunoglobulin G (IgG) autoantibodies, glomerulonephritis, osteopenia, and atherosclerotic lesions on a normal chow diet.

Methods

Female mice, starting at eight to nine weeks of age, were treated for 27 weeks with 1) pravastatin, 2) L-4F, 3) L-4F plus pravastatin, or 4) vehicle control, followed by disease phenotype assessment.

Results

In preliminary studies, dysfunctional, proinflammatory high-density lipoproteins (piHDL) were decreased six hours after a single L-4F, but not scrambled L-4F, injection in eight- to nine-week old mice. After 35 weeks, L-4F-treated mice, in the absence/presence of pravastatin, had significantly smaller lymph nodes and glomerular tufts (P_{L, LP} < 0.05), lower serum levels of IgG antibodies to double stranded DNA (dsDNA) (P_L < 0.05) and oxidized phospholipids (oxPLs) (P_{L, LP} < 0.005), and elevated total and vertebral bone mineral density (P_{L, LP} < 0.01) compared to vehicle controls. Although all treatment groups presented larger aortic root lesions compared to vehicle controls, enlarged atheromas in combination treatment mice had significantly less infiltrated CD68⁺ macrophages (P_LP < 0.01), significantly increased mean α-actin stained area (P_LP < 0.05), and significantly lower levels of circulating markers for atherosclerosis progression, CCL19 (P_{L, LP} < 0.0005) and VCAM-1 (P_L < 0.0002).

Conclusions

L-4F treatment, alone or with pravastatin, significantly reduced IgG anti-dsDNA and IgG anti-oxPLs, proteinuria, glomerulonephritis, and osteopenia in a murine lupus model of accelerated atherosclerosis. Despite enlarged aortic lesions, increased smooth muscle content, decreased macrophage infiltration, and decreased pro-atherogenic chemokines in L-4F plus pravastatin treated mice suggest protective mechanisms not only on lupus-like disease, but also on potential plaque remodeling in a murine model of systemic lupus erythematosus (SLE) and accelerated atherosclerosis.     

Keratinocyte growth factor/fibroblast growth factor-7-regulated cell migration and invasion through activation of NF-kappaB transcription factors

Keratinocyte growth factor (KGF)/fibroblast growth factor-7 (FGF-7) is a paracrine- and epithelium-specific growth factor produced by cells of mesenchymal origin. It acts exclusively through FGF-7 receptor (FGFR2/IIIb), which is expressed predominantly by epithelial cells, but not by fibroblasts, suggesting that it might function as a paracrine mediator of mesenchymal-epithelial interactions. KGF/FGF-7 plays an essential role in the growth of epithelial cells and is frequently overexpressed in cancers of epithelial origin such as pancreatic cancer, switching paracrine stimulation of KGF/FGF-7 to an autocrine loop. Less is known, however, about the signaling pathways by which KGF/FGF-7 regulates the response of epithelial cells. To delineate the signaling pathways activated by KGF/FGF-7 and examine cellular response to KGF/FGF-7 stimulation, we performed functional analysis of KGF/FGF-7 action. In this report, we show that KGF/FGF-7 activated nuclear factor kappaB (NF-kappaB), which in turn induced expression of VEGF, MMP-9, and urokinase-type plasminogen activator and increased migration and invasion of KGF/FGF-7-stimulated human pancreatic ductal epithelial cells. Expression of phosphorylation-defective IkappaBalpha (IkappaBalphaS32A,S36A), which blocked NF-kappaB activation, inhibited KGF/FGF-7-induced gene expression and cell migration and invasion. Our results demonstrate for the first time that KGF/FGF-7 induces NF-kappaB activation and that NF-kappaB plays an essential role in regulation of KGF/FGF-7-inducible gene expression and KGF/FGF-7-initiated cellular responses. Thus, these findings identify one signaling pathway for KGF/FGF-7-regulated cell migration and invasion and suggest that paracrine sources of KGF/FGF-7 are one of the malignancy-contributing factors from tumor stroma.     

The discovery of potent, selective, and orally bioavailable hNK1 antagonists derived from pyrrolidine

SAR studies on amides, ureas, and vinylogous amides derived from pyrrolidine led to the discovery of several potent hNK(1) antagonists. One particular vinylogous amide (45b) had excellent potency, selectivity, pharmacokinetic profile, and functional activity in vivo. An in vivo rhesus macaque brain receptor occupancy PET study for compound 45b revealed an estimated Occ(90) approximately 300 ng/ml.     

Rapamycin enriches for CD4(+) CD25(+) CD27(+) Foxp3(+) regulatory T cells in ex vivo-expanded CD25-enriched products from healthy donors and patients with multiple sclerosis

BACKGROUND: CD4(+) CD25(bright+) regulatory T cells (Treg) can be expanded to clinical doses using CD3/CD28 Ab-coated beads plus IL-2. However, this method requires high purity of the starting population to prevent overgrowth by non-regulatory T cells. Rapamycin, an agent that inhibits T-cell proliferation but selectively spares Treg, may be a means to expand Treg from less pure CD25-enriched cells. METHODS: CD25-enriched cells were prepared by a single-step immunomagnetic-selection using anti-CD25 microbeads. The cells were activated with a single addition of anti-CD3/CD28 beads and expanded in ex vivo 15-5% HS and autologous CD4(+) CD25(-) feeder cells,+/-rapamycin (0.01-20 ng/mL). IL-2 was added on day 3. Cells were rested for 2 days in ex vivo 15-5% HS and tested for phenotype, intracellular Foxp3 protein and suppressor activity. RESULTS: In the absence of rapamycin, CD25-enriched fractions expanded >17 000-fold by 21 days. Although suppressor activity was detected to day 14, it declined significantly by 21 days as non-regulatory cells expanded. The addition of rapamycin inhibited expansion of non-regulatory T cells at doses > or =1 ng/mL while increasing suppressor activity and the percentage of CD4(+) CD25(+) CD27(+) Foxp3(+) cells. Rapamycin did not enrich for Foxp3(+) cells in expanded cultures of CD4(+) CD25(-) cells. Treg were also readily expanded in cultures of CD25-enriched cells obtained from patients with multiple sclerosis in the presence of rapamycin. DISCUSSION: The addition of 1-20 ng/mL rapamycin to CD25-enriched cultures increased the purity of cells with the phenotype and function of Treg. This approach may alleviate the need for rigorous enrichment of Treg prior to activation and expansion for potential clinical use.     

Oestrogen receptors interact with the α-catalytic subunit of AMP-activated protein kinase

Normal and pathological stressors engage the AMP-activated protein kinase (AMPK) signalling axis to protect the cell from energetic pressures. Sex steroid hormones also play a critical role in energy metabolism and significantly modify pathological progression of cardiac disease, diabetes/obesity and cancer. AMPK is targeted by 17β-oestradiol (E2), the main circulating oestrogen, but the mechanism by which E2 activates AMPK is currently unknown. Using an oestrogen receptor α/β (ERα/β) positive (T47D) breast cancer cell line, we validated E2-dependent activation of AMPK that was mediated through ERα (not ERβ) by using three experimental strategies. A series of co-immunoprecipitation experiments showed that both ERs associated with AMPK in cancer and striated (skeletal and cardiac) muscle cells. We further demonstrated direct binding of ERs to the α-catalytic subunit of AMPK within the βγ-subunit-binding domain. Finally, both ERs interacted with the upstream liver kinase B 1 (LKB1) kinase complex, which is required for E2-dependent activation of AMPK. We conclude that E2 activates AMPK through ERα by direct interaction with the βγ-binding domain of AMPKα.