Stochastic programming for outpatient scheduling with flexible inpatient exam accommodation

This study is concerned with the determination of an optimal appointment schedule in an outpatient-inpatient hospital system where the inpatient exams can be cancelled based on certain rules while the outpatient exams cannot be cancelled. Stochastic programming models were formulated and solved to tackle the stochasticity in the procedure durations and patient arrival patterns. The first model, a two-stage stochastic programming model, is formulated to optimize the slot size. The second model further optimizes the inpatient block (IPB) placement and slot size simultaneously. A computational method is developed to solve the second optimization problem. A case study is conducted using the data from Magnetic Resonance Imaging (MRI) centers of Lahey Hospital and Medical Center (LHMC). The current schedule and the schedules obtained from the optimization models are evaluated and compared using simulation based on FlexSim Healthcare. Results indicate that the overall weighted cost can be reduced by 11.6% by optimizing the slot size and can be further reduced by an additional 12.6% by optimizing slot size and IPB placement simultaneously. Three commonly used sequencing rules (IPBEG, OPBEG, and a variant of ALTER rule) were also evaluated. The results showed that when optimization tools are not available, ALTER variant which evenly distributes the IPBs across the day has the best performance. Sensitivity analysis of weights for patient waiting time, machine idle time and exam cancellations further supports the superiority of ALTER variant sequencing rules compared to the other sequencing methods. A Pareto frontier was also developed and presented between patient waiting time and machine idle time to enable medical centers with different priorities to obtain solutions that accurately reflect their respective optimal tradeoffs. An extended optimization model was also developed to incorporate the emergency patient arrivals. The optimal schedules from the extended model show only minor differences compared to those from the original model, thus proving the robustness of the scheduling solutions obtained from our optimal models against the impacts of emergency patient arrivals.

     

RTS,S/AS01E malaria vaccine induces IgA responses against CSP and vaccine-unrelated antigens in African children in the phase 3 trial

BackgroundThe evaluation of immune responses to RTS,S/AS01 has traditionally focused on immunoglobulin (Ig) G antibodies that are only moderately associated with protection. The role of other antibody isotypes that could also contribute to vaccine efficacy remains unclear. Here we investigated whether RTS,S/AS01_E elicits antigen-specific serum IgA antibodies to the vaccine and other malaria antigens, and we explored their association with protection.MethodsNinety-five children (age 5–17 months old at first vaccination) from the RTS,S/AS01_E phase 3 clinical trial who received 3 doses of RTS,S/AS01_E or a comparator vaccine were selected for IgA quantification 1 month post primary immunization. Two sites with different malaria transmission intensities (MTI) and clinical malaria cases and controls, were included. Measurements of IgA against different constructs of the circumsporozoite protein (CSP) vaccine antigen and 16 vaccine-unrelated Plasmodium falciparum antigens were performed using a quantitative suspension array assay.ResultsRTS,S vaccination induced a 1.2 to 2-fold increase in levels of serum/plasma IgA antibodies to all CSP constructs, which was not observed upon immunization with a comparator vaccine. The IgA response against 13 out of 16 vaccine-unrelated P. falciparum antigens also increased after vaccination, and levels were higher in recipients of RTS,S than in comparators. IgA levels to malaria antigens before vaccination were more elevated in the high MTI than the low MTI site. No statistically significant association of IgA with protection was found in exploratory analyses.ConclusionsRTS,S/AS01_E induces IgA responses in peripheral blood against CSP vaccine antigens and other P. falciparum vaccine-unrelated antigens, similar to what we previously showed for IgG responses. Collectively, data warrant further investigation of the potential contribution of vaccine-induced IgA responses to efficacy and any possible interplay, either synergistic or antagonistic, with protective IgG, as identifying mediators of protection by RTS,S/AS01_E immunization is necessary for the design of improved second-generation vaccines.Clinical trial registration: ClinicalTrials.gov: NCT008666191.     

Bivalent non-typhoidal Salmonella outer membrane vesicles immunized mice sera confer passive protection against gastroenteritis in a suckling mice model

Invasive non-typhoidal Salmonella (iNTS) serovars, especially Salmonella Typhimurium (ST) and Salmonella Enteritidis (SE), cause gastroenteritis worldwide. Due to the emergence of multi-drug resistance in iNTS, a broad-spectrum vaccine is urgently needed for the prevention of iNTS infection. Currently, there is no effective licensed vaccine against iNTS available in the market. We have formulated an outer membrane vesicles (OMVs) based bivalent immunogen as a vaccine candidate to generate broad-spectrum protective immunity against both recently circulating prevalent ST and SE. We have isolated OMVs from ST and SE and formulated the immunogen by mixing both OMVs (1:1 ratio). Three doses of bivalent immunogen significantly induced humoral immune responses against lipopolysaccharides (LPSs) and outer membrane proteins (OMPs) as well as a cell-mediated immune response in adult mice. We also observed that proteins of OMVs act as an adjuvant for generation of high levels of anti-LPS antibodies through T cell activation. We then characterized the one-day old suckling mice model for both ST and SE mediated gastroenteritis and used the model for a passive protection study. In the passive protection study, we found the passive transfer of bivalent OMVs immunized sera significantly reduced ST and SE mediated colonization and gastroenteritis symptoms in the colon of suckling mice compared to non-immunized sera recipients. The overall study demonstrated that OMVs based bivalent vaccine could generate broad-spectrum immunity against prevalent iNTS mediated gastroenteritis. This study also established the suckling mice model as a suitable animal model for vaccine study against iNTS mediated gastroenteritis.     

Mycobacterium ulcerans-specific immune response after immunisation with bacillus Calmette-Guérin (BCG) vaccine

BackgroundBacillus Calmette–Guérin (BCG) vaccine provides partial protection against Buruli ulcer caused by Mycobacterium ulcerans in epidemiological studies. This study aimed to quantify M. ulcerans-specific immune responses induced by BCG immunisation.MethodsIntracellular cytokine analysis of in-vitro experiments done 10 weeks after BCG immunisation in 130 Australian infants randomised to one of three BCG vaccine strains given either at birth (BCG-Denmark, BCG-Japan, or BCG-Russia) or at two months of age (BCG-Denmark).ResultsProportions of polyfunctional CD4⁺ T-cells were higher in M. ulcerans-stimulated compared to unstimulated control samples. These proportions were not influenced by the vaccine strain or timing of the immunisation. The M. ulcerans-specific immune responses showed similar patterns to those observed in M. tuberculosis-stimulated samples, although they were of lower magnitude.ConclusionsOur data show that BCG immunisation induces M. ulcerans-specific immune responses in infants, likely explaining the cross-protective effect observed in epidemiological studies. (ACTRN12608000227392)     

Strain difference in transgene-induced tumorigenesis and suppressive effect of ionizing radiation

Transgenic expression in medaka of the Xiphophorus oncogene xmrk, under a pigment cell specific mitf promoter, induces hyperpigmentation and pigment cell tumors. In this study, we crossed the Hd-rR and HNI inbred strains because complete genome information is readily available for molecular and genetic analysis. We prepared an Hd-rR (p53^+/−, p53^−/−) and Hd-rR HNI hybrid (p53^+/−) fish-based xmrk model system to study the progression of pigment cells from hyperpigmentation to malignant tumors on different genetic backgrounds. In all strains examined, most of the initial hyperpigmentation occurred in the posterior region. On the Hd-rR background, mitf:xmrk-induced tumorigenesis was less frequent in p53^+/− fish than in p53^−/− fish. The incidence of hyperpigmentation was more frequent in Hd-rR/HNI hybrids than in Hd-rR homozygotes; however, the frequency of malignant tumors was low, which suggested the presence of a tumor suppressor in HNI genetic background fish. The effects on tumorigenesis in xmrk-transgenic immature medaka of a single 1.3 Gy irradiation was assessed by quantifying tumor progression over 4 consecutive months. The results demonstrate that irradiation has a different level of suppressive effect on the frequency of hyperpigmentation in purebred Hd-rR compared with hybrids.     

Scope of health systems research in Child Survival and Safe Motherhood programme

Editorial commentary focused on several Health System Research (HSR) approaches which exemplified some of the key issues for application of HSR for further improvement in Maternal and Child Health (MCH) services in India. The goals of HSR are to delineate health policy which improves the operations of the health care delivery system for sustainability at the district level. HSR is part of a global effort of Health For All by 2000 AD and India's Child Survival and Safe Motherhood (CSSM) program, sponsored by IDA/UNICEF. CSSM aims also to end polio by 2000 AD, eliminate neonatal tetanus by 1995, and prevent deaths and morbidity from measles, diarrheal diseases, and acute respiratory infection. MCH services will be expanded at the village, subcenter, primary health center, and community health center levels in order to reduce maternal mortality to below 2/1000 from the 1990 5/1000 and to reduce mortality of children aged 1-4 years to less than 10/1000 live births from 80/1000 by 2000 AD. States with particularly high levels of child and maternal mortality are Bihar, Uttar Pradesh, Rajasthan, and Madhya Pradesh, which have about 40% of India's population. These states have low marriage ages, low female literacy, and few women in nonagricultural employment. There are about 90 districts in these states with particularly low demographic indicators. India policy directs all CSSM work to be carried out by existing staff; the program emphasis will be training, supervision, and logistics. IEC will need to be directed to attitudinal change in rural areas and urban slums. Research has found that coverage is uneven and quality of MCH services, poor. One study will evaluate the performance over 5 years in Gwalior district in a nutrition and school health program. Another research effort will perform quality assessment of MCH care at the primary health care level and promote community awareness and increased utilization. An ongoing study is evaluating nationally the family welfare services and MCH program at the primary health center level. The several agencies conducting HSR included the National Institute of Health and Family Welfare, the Indian Council of Medical Research, and the BJ Medical College. Multidisciplinary research is still needed in order to understand the malnutrition among pregnant mothers and use of health services by women.     

Evaluation of beta-tethymustine, a new anticancer compound, in murine tumour models

beta-Tethymustine, 1-[2- {bis(2'-chloroethyl)amino}ethyl]spiro[imidazolidine-4,2'-(1'H),3',4'-dihydronaphthalene]-2,5-dione, has been synthesised and LD50 value determined in Swiss male mice, which was found to be 100.00 mg/kg by single i.p. injection. The following three criteria, namely ascites cell count, ascites fluid measurement and increase in median survival times (MST) of drug-treated (T) over untreated control (C) mice, were studied for evaluation of its antitumour efficacy in vivo in three murine ascites tumours, namely Ehrlich ascites carcinoma (EAC), sarcoma-180 (S-180) and Dalton's lymphoma (DL). At the optimum dose range of 8.0 mg/kg (higher) to 4.0 mg/kg (lower) for 1-7 days treatment following tumour transplantation on day 0, it exhibited a very high percentage of inhibition of both the ascites cell and fluid in these models and displayed excellent ILS(max) value of 80 in EAC, 224 in S-180 and 240 in DL, respectively, showing 'curative' effect (2-3/6 mice having 90 days survival rate). It also demonstrated a high ILS value of 150 with one cure/six mice bearing S-180 for 6 days prior to drug therapy. Screening results were compared with two clinical drugs, cyclophosphamide and 5-fluorouracil, serving as positive controls. Its chemical alkylating activity was compared with nor-HN2 (NSC 10873) and spiromustine (NSC 172112). The results indicate that it possesses greater alkylating activity than nor-HN2 and comparable activity with spiromustine.