Analysis of Transmission of Infection in Epidemics: Confined Random Walkers in Dimensions Higher Than One.

The process of transmission of infection in epidemics is analyzed by studying a pair of random walkers, the motion of each of which in two dimensions is confined spatially by the action of a quadratic potential centered at different locations for the two walks. The walkers are animals such as rodents in considerations of the Hantavirus epidemic, infected or susceptible. In this reaction-diffusion study, the reaction is the transmission of infection, and the confining potential represents the tendency of the animals to stay in the neighborhood of their home range centers. Calculations are based on a recently developed formalism (Kenkre and Sugaya in Bull Math Biol 76:3016-3027, 2014) structured around analytic solutions of a Smoluchowski equation and one of its aims is the resolution of peculiar but well-known problems of reaction-diffusion theory in two dimensions. The resolution is essential to a realistic application to field observations because the terrain over which the rodents move is best represented as a 2-d landscape. In the present analysis, reaction occurs not at points but in spatial regions of dimensions larger than 0. The analysis uncovers interesting nonintuitive phenomena one of which is similar to that encountered in the one-dimensional analysis given in the quoted article, and another specific to the fact that the reaction region is spatially extended. The analysis additionally provides a realistic description of observations on animals transmitting infection while moving on what is effectively a two-dimensional landscape. Along with the general formalism and explicit one-dimensional analysis given in Kenkre and Sugaya (2014), the present work forms a model calculational tool for the analysis for the transmission of infection in dilute systems.

A hollow-fibre column system to effectively prepare washed platelets.

BACKGROUND AND OBJECTIVES: We developed a hollow-fibre column system specifically adapted to prepare washed platelet concentrates (WPCs). This study was performed to evaluate the efficacy of the hollow-fibre column system for preparing WPCs. MATERIALS AND METHODS: First, the percentages of platelet (PLT) recovery and remaining plasma proteins were calculated by determining the PLT count, volume and plasma protein levels in both the prewash and postwash. Secondly, washed PLTs and unwashed control PLTs were stored for 5 days, and the changes during this 5-day storage of in vitro PLT characteristics were determined. RESULTS: The hollow-fibre column system effectively removed >98% of plasma in platelet concentrates (PCs), and the PLT recovery was 97% on an average. The CD62P-expression level on washed PLTs immediately after washing was approximately twofold higher than that on prewashed PLTs as well as on PLTs washed via manual methods or cell washing devices. Until day 5 during storage, PLT aggregability, hypotonic shock response and swirling scores of washed PLTs were not significantly different from those of the control PCs. CONCLUSION: Our novel hollow-fibre column system proved valuable in preparing washed PLTs with <2% of residual plasma proteins and high recovery of PLTs.

Theory of the transmission of infection in the spread of epidemics: interacting random walkers with and without confinement.

A theory of the spread of epidemics is formulated on the basis of pairwise interactions in a dilute system of random walkers (infected and susceptible animals) moving in [Formula: see text] dimensions. The motion of an animal pair is taken to obey a Smoluchowski equation in [Formula: see text]-dimensional space that combines diffusion with confinement of each animal to its particular home range. An additional (reaction) term that comes into play when the animals are in close proximity describes the process of infection. Analytic solutions are obtained, confirmed by numerical procedures, and shown to predict a surprising effect of confinement. The effect is that infection spread has a non-monotonic dependence on the diffusion constant and/or the extent of the attachment of the animals to the home ranges. Optimum values of these parameters exist for any given distance between the attractive centers. Any change from those values, involving faster/slower diffusion or shallower/steeper confinement, hinders the transmission of infection. A physical explanation is provided by the theory. Reduction to the simpler case of no home ranges is demonstrated. Effective infection rates are calculated, and it is shown how to use them in complex systems consisting of dense populations.

Quadruplet pregnancy complicated by ovarian hyperstimulation syndrome with spontaneous ovulation.

Ovarian hyperstimulation syndrome (OHSS) commonly occurs as a complication of ovarian stimulation with gonadotrophins. Spontaneous OHSS is an extremely rare event, but can occur as a result of stimulation with pregnancy-derived hCG. We herein report a case of quadruplet pregnancy complicated by OHSS with spontaneous ovulation. The patient had previously undergone ovarian stimulation with clomiphene citrate plus FSH. After that, she conceived spontaneously and developed OHSS after three weeks of amenorrhea. The OHSS was managed by conservative treatment and improved at six weeks of gestation. However, a quadruplet pregnancy became apparent on ultrasound examination. The patient therefore elected to have an induced abortion. Besides the conception in the cycle without administration of exogenous gonadotrophins, the symptoms in this case had the same kinetics as iatrogenic OHSS caused by ovarian stimulation.

A case of polycystic ovary syndrome conceived by intracytoplasmic sperm injection following laparoscopic ovarian drilling.

Polycystic ovary syndrome (PCOS) is a disease in which an ovulation disorder is the main cause of infertility. Clomifene citrate (CC) is the treatment of first choice for ovulation induction in PCOS. If ovulation cannot be induced by CC, then either laparoscopic ovarian drilling (LOD) or gonadotropin therapy is selected as a subsequent treatment. Assisted reproductive technology (ART) is indicated for women with PCOS, similar to other infertility patients, when pregnancy is not achieved by intrauterine insemination (IUI). In this study, we experienced a case of PCOS in which pregnancy was achieved by ART following LOD. The case pertains to a 26-year-old patient. She consulted our hospital with a chief complaint of primary infertility. IUI with administration of CC plus recombinant follicle-stimulating hormone (rFSH) was carried out; however, pregnancy was not achieved. Subsequently, ART was carried out. In the first attempt, the development of several follicles was observed under the gonadotropin releasing hormone (GnRH) agonist long protocol. However, a fertilized oocyte was not obtained. In the second attempt, an ovum could not be collected after CC-rFSH ovarian stimulation. In the third attempt, a good quality embryo could not be obtained under the GnRH antagonist protocol, and therefore pregnancy could not be achieved. We performed LOD using a harmonic scalpel for the purpose of preventing severe OHSS and improving the quality of embryos. Following the operation, ovarian stimulation was performed under the CC-rFSH-antagonist protocol. Eighteen follicles were aspirated, six oocytes were picked-up, and five oocytes were normally fertilized. As a result, four embryos from day 2 culture were cryopreserved. Cryopreserved-thawed embryo transfer was thereafter performed, and a single pregnancy was achieved. LOD is a clinically effective treatment for PCOS requiring ART.

Severe Asherman's syndrome complicated with placenta increta conceived by intracytoplasmic sperm injection following hysteroscopic surgery.

Although severe Asherman's syndrome is a disease that may cause infertility, pregnancy and childbirth are possible by performing hysteroscopic surgery. However, the obstetrical outcome is not always satisfactory. We report a case where severe Asherman's syndrome occurred following a cesarean section. Hysteroscopic surgery was performed due to secondary infertility, and pregnancy was achieved through a subsequent intracytoplasmic sperm injection. At 23 weeks of gestation, the patient was hospitalized due to the threat of premature labor, and a cesarean section was performed at 29 weeks of gestation after pregnancy-induced hypertension occurred. It was determined to be abnormal adherent placentation such as placenta increta through intraoperative findings, and a cesarean hysterectomy was performed. The pathological diagnosis of the uterus was placenta increta. Due to the risk of complications from placenta increta in pregnancies following hysteroscopic surgery in patients with severe Asherman's syndrome, it is important to realize the high risk involved in such cases during the pregnancy course, and careful perinatal management should be required.

Pregnancy following calcium ionophore oocyte activation in an oligozoospermia patient with repeated failure of fertilization after ICSI.

A successful pregnancy outcome after calcium ionophore A23187 oocyte activation in an infertile couple with a repeated failure of achieving fertilization after ICSI is reported. The secondary infertility couple with oligozoospermia underwent ICSI two times. However, none of the oocytes were fertilized. In the third ICSI attempt, three oocytes after ICSI were activated using calcium ionophore for five minutes. Two of three oocytes thus became fertilized. A successful pregnancy outcome was thereafter achieved with the delivery of a healthy infant without congenital abnormalities. Oocyte activation using calcium ionophore was thus found to be a useful method in a case of repeated failure of fertilization after ICSI.

Twin pregnancy after in vitro fertilization in a woman with a unicornuate uterus.

A unicornuate uterus is a rare congenital uterovaginal anomaly. A unicornuate uterus is associated with infertility, cervical incompetence, and premature labor. A case of a 32-year-old null gravid female with a unicornuate uterus who had wished to bear a child for five years is reported. After undergoing insemination treatment with the husband's semen, in vitro fertilization was performed and a twin pregnancy occurred. A successful outcome was achieved with the delivery of viable infants following intensive obstetric management.

Increase in ultraviolet sensitivity by overexpression of calpastatin in ultraviolet-resistant UVr-1 cells derived from ultraviolet-sensitive human RSa cells.

Human RSa cells are highly sensitive to apoptotic-like cell death by ultraviolet irradiation (UV) while UVr-1 cells are their variant with an increased resistance to UV. Three days after UV at 10 J/m2, the viability of RSa cells was approximately 17% while that of UVr-1 cells was 65%. This different survival might reflect apoptotic cell death since apoptosis-specific DNA ladder was more clearly observed in RSa cells than in UVr-1 cells after UV. Addition of ALLN/calpain inhibitor I to the culture medium after UV resulted in similar survival (14 - 18%) between RSa and UVr-1 cells. Immunoblot analysis showed down-regulation of protein kinase CTheta, Src, Bax and mu-calpain after UV was more prominent in UVr-1 than in RSa cells. Activated mu-calpain appeared within 1 h post-UV only in UVr-1 cells. The expression of calpastatin, a specific endogenous inhibitor of calpain, was higher in RSa than in UVr-1 cells. To further examine the role of calpain in UV-induced cell death, cDNA of human calpastatin was transfected into UVr-1 cells. The results showed that overexpression of calpastatin suppressed down-regulation of Src, mu-calpain and Bax. Concomitantly, colony survival after UV was reduced in calpastatin-transfected cells as compared to vector control cells. Our results suggest that activation of calpain might account for, at least in part, the lower susceptibility to UV-induced cell death in UVr-1 cells.

Development of novel cationic liposomes for efficient gene transfer into peritoneal disseminated tumor.

A novel series of cationic lipids has been found, by in vivo screening, to be effective for gene transfer into peritoneal disseminated tumor. O,O'-Ditetradecanoyl-N-(alpha-trimethylammonioacetyl)diethan olamine chloride (DC-6-14), having dimyristyl acid, has shown the highest transfection activity in vitro, provided that 10% fetal bovine serum is present. To enhance the transfection efficiency of DC-6-14, we added dioleoylphosphatidylethanolamine (DOPE) and/or cholesterol (Chol) as helper lipids in various ratios. Cationic liposomes containing DC-6-14, DOPE, and Chol in molar ratios of 1:0.75:0.75 and 1:1:0.8 maintained efficient transfection activity under serum-containing conditions in HRA, mEIIL, and ES-2 cell lines in vitro, as determined by luciferase assay. With our novel liposomes, transfection efficiencies were higher in cells proliferating faster than in cells proliferating slower, depending on mitotic activity as represented by labeling index. In the mEIIL peritoneal disseminated tumor model, cancer cells were specifically transfected with the lacZ gene. Gene transfer was observed by X-Gal staining not only in floating cancer cells in the ascites, but also in the peritoneal disseminated cancer tissue. The percentage of LacZ-positive cells was about 1%, which was significantly higher than with commercially available Lipofectin (0.38%), LipofectACE (0.62%), or LipofectAMINE (0.23%). In the mEIIL peritoneal disseminated tumor-nude mouse model, herpes simplex thymidine kinase gene (HSV tk) transfer with our novel liposomes, followed by ganciclovir (GCV) treatment, resulted in significantly longer survival compared with control mice (p < 0.05, Cox-Mantel). These results suggest that these liposomes show promise as tools in gene therapy for patients with intraperitoneal disseminated cancer.

Inhibition of tumor growth by direct intratumoral gene transfer of herpes simplex virus thymidine kinase gene with DNA-liposome complexes.

To establish the expression of the herpes simplex virus thymidine kinase (HSV-TK) gene in tumor cells, we analyzed the promoter function of the SV40 promoter and the nucleotide sequence (CACGTG) to which Myc-Max heterodimers (Myc/Max) were capable of binding in four kinds of cell lines: COLO320 DM, A-431, KF, and Nakajima. When luciferase reporter plasmid under the control of SV40 promoter was transfected into tumor cells in vitro, a high level of luciferase activity was observed in all kinds of cell lines. However, by transfection of the luciferase gene promoted by the Myc/Max binding sequence, accelerated luciferase expression was observed in COLO320 DM and A-431 cells with high expression of c-myc, but not in KF and Nakajima cells, which showed low expression of c-myc. The repeated transfection of the liposome-conjugated HSV-TK gene regulated by the SV40 promoter and cultivation in 100 micrograms/ml of aciclovir for 5 days in vitro demonstrated growth inhibition for all four kinds of cell lines. However, cell toxicity was observed only in COLO320 DM and A-431 cells when the HSV-TK gene promoted by the Myc/Max binding sequence was introduced. (The survival rate to 100 micrograms/ml of aciclovir concentration in COLO320 DM, A-431, KF, and Nakajima cells was 59%, 53%, 74%, and 79%, respectively.) In vivo direct injection of the liposome-conjugated HSV-TK gene regulated by the SV40 promoter into established tumors and aciclovir administration for 10 days into the mice resulted in significant tumor volume reduction in three tested tumor cells. However, injection of the HSV-TK gene promoted by the Myc/Max binding sequence and aciclovir administration into mice could achieve significant tumor regression only in COLO320 DM and A-431 cells. These results suggest that gene therapy using the HSV-TK gene promoted by the Myc/Max binding sequence can be an attractive approach for treatment against tumor cells expressing high levels of c-myc.

Suppression of okadaic acid-induced apoptosis by overexpression of calpastatin in human UV(r)-1 cells.

Proteolytic systems have various involvements in apoptotic pathways. To understand the role of calpain in apoptosis, calpastatin, a specific inhibitor of calpain, was overexpressed in human UV(r)-1 fibroblasts by transfection of its cDNA. The elevated expression of calpastatin resulted in decreased survival in the presence of okadaic acid (OA) but in no apparent alteration in the sensitivity toward other drugs such as 5-fluorouracil, mitomycin C and methotrexate. After treatment with OA, a typical apoptotic DNA ladder was observed in control vector-transfected cells but not in calpastatin-transfected cells. This indicates that OA-induced apoptosis was suppressed by overexpression of calpastatin. Further immunoblot analysis showed that the OA-induced hyperphosphorylation of c-Jun was inhibited in calpastatin-transfected cells. This might be involved in the resistance to OA-induced cell death in calpastatin-overproducing cells.

Activation of MAP kinases by 5-fluorouracil in a 5-fluorouracil-resistant variant human cell line derived from a KT breast cancer cell line.

To investigate the mechanism of the acquired resistance of human cells to an anticancer drug, 5-fluorouracil (5-FU), a drug-resistant clone, KTFU-4, was isolated from a human KT breast carcinoma cell line, treated with ethylmethanesulfonate and then with 5-FU. The viability of the KT cells, analyzed using an MTT assay, was suppressed by 5-FU in a dose-dependent manner, while that of the KTFU-4 cells was enhanced by it at concentrations between 0.1 and 1.0 microgram/ml. Treatment of KTFU-4 cells with 5-FU resulted in increased amounts of activated phosphorylated ERK1/2 and p38 MAP kinases, but not in the parent KT cells. It is thus possible that 5-FU stimulated the proliferation of KTFU-4 cells by activating a signal transduction pathway leading to cell growth.

Involvement of LEU13 in interferon-induced refractoriness of human RSa cells to cell killing by X rays.

Culture of human cells with human interferon alpha and beta (IFNA and IFNB) results in increased resistance of the cells to cell killing by X rays. To identify candidate genes responsible for the IFN-induced X-ray resistance, we searched for genes whose expression levels are increased in human RSa cells treated with IFNA, using an mRNA differential display method and Northern blotting analysis. RSa cells, which showed increased survival (assayed by colony formation) after X irradiation when they were treated with IFNA prior to irradiation, showed increased expression levels of LEU13 (IFITM1) mRNA after IFNA treatment alone. In contrast, IF(r) and F-IF(r) cells, both of which are derived from RSa cells, showed increased X-ray resistance and high constitutive LEU13 mRNA expression levels compared to the parental RSa cells. Furthermore, the IFNA-induced resistance of RSa cells to killing by X rays was suppressed by antisense oligonucleotides for LEU13 mRNA. LEU13, a leukocyte surface protein, was previously reported to mediate the actions of IFN such as inhibition of cell proliferation. The present results suggest a novel role of LEU13 different from that in the inhibition of cell proliferation, involved in IFNA-induced refractoriness of RSa cells to X rays.

Gene delivery using liposome technology.

Development of more reliable liposomal formulations and preparation methods which can be used for gene therapy instead of commonly used viral vectors is expected. We have already developed the freeze-dried empty (non-drug-containing) liposomes (FDEL) method for mass-production of liposomal products. After these freeze-dried empty liposomes are rehydrated with aqueous drug solutions, many kinds of drugs can be encapsulated highly efficiently, and particle size can be controlled well. This study evaluated the usefulness of this FDEL method for preparation of liposomes containing DNA with a particular attention to the stability of DNA. When the liposomes were prepared by the conventional lipid-film method on a relatively large scale with use of a Potter-homogenizer (a teflon homogenizer), significant degradation and conformational change of DNA was observed during homogenization. Loss of DNA was also significant after extrusion for sizing and sterilization; residual DNA in the final preparation was hardly detected. When the FDEL method was used, on the other hand, no degradation, conformational change or loss of DNA was observed, and particle size was easily controlled. Moreover, there was no significant difference in luciferase activity between the lipid-film method used on a small scale with use of a vortex mixer and the FDEL method after transfection of tumor cells (HRA, HEC-1A and Colo320DM) by the liposomes containing DNA (PGV-C). These findings suggest that the FDEL method is very useful for preparation of liposomes containing DNA.

Mutagenicity of bisphenol A and its suppression by interferon-alpha in human RSa cells.

Bisphenol A is used as a monomer in the production of polycarbonate plastic products. The widespread use of bisphenol A has raised concerns about its effects in humans. Since there is little information on the mutagenic potential of the chemical, the mutagenicity of bisphenol A was tested using human RSa cells, which has been utilized for identification of novel mutagens. In genomic DNA from cells treated with bisphenol A at concentrations ranging from 1x10(-7) to 1x10(-5)M, base substitution mutations at K-ras codon 12 were detected using PCR and differential dot-blot hybridization with mutant probes. Mutations were also detected using the method of peptide nucleic acid (PNA)-mediated PCR clamping. The latter method enabled us to detect the mutation in bisphenol A-treated cells at a dose (1x10(-8)M) equivalent to that typically found in the environment. Induction of ouabain-resistant (Oua(R)) phenotypic mutation was also found in cells treated with 1x10(-7) and 1x10(-5)M of bisphenol A. The induction of K-ras codon 12 mutations and Oua(R) mutations was suppressed by pretreating RSa cells with human interferon (HuIFN)-alpha prior to bisphenol A treatment. The cells treated with bisphenol A at the concentration of 1x10(-6)M elicited unscheduled DNA synthesis (UDS). These findings suggested that bisphenol A has mutagenicity in RSa cells as well as mutagens that have been tested in these cells, and furthermore, that a combination of the PNA-mediated PCR clamping method with the human RSa cell line may be used as an assay system for screening the mutagenic chemicals at very low doses.

Palmar fasciitis and polyarthritis associated with squamous cell carcinoma of the cervix.

Palmar fasciitis and polyarthritis (PFPA) is an uncommon syndrome characterized by progressive and extensive rheumatic disease. We present the first example of PFPA in association with squamous cell carcinoma of the uterine cervix and peritoneal carcinoma. A 54-year-old woman developed pain in both shoulders and flexion deformities of all fingers in both hands due to an increasing swelling of both palms. She underwent surgery and histologic examination of the removed uterus revealed squamous cell carcinoma, nonkeratinizing type with a small portion of undifferentiated carcinoma. Chemotherapy resulted in an excellent response, during which the arthritic symptoms improved gradually. PFPA can occur in a wide range of cancers and warrants extensive investigation for a malignant tumor.

Infectivity of feline enteroepithelial stages of Toxoplasma gondii isolated by Percoll-density gradient centrifugation.

The infectivity of the feline enteroepithelial stages of Toxoplasma gondii isolated by Percoll-density gradient centrifugation was examined by the trypan blue dye exclusion method by assaying their penetration into feline fibroblast cells in vitro and by inoculation of the intestinal mucosa of cats. A large population of the parasites showed trypan blue dye exclusion activity. When feline fibroblast cells were inoculated with feline enteroepithelial stage parasites, no intracellular parasites were found 18 h post-inoculation. Kittens inoculated intraduodenally with 2 x 10(6) feline enteroepithelial stage parasites shed oocysts between 2 and 8 days post-inoculation. These results indicate that the isolated feline enteroepithelial stage parasites display infectivity towards enterocytes of cats and are capable of gametogenesis.

Increased and decreased expression of CD69 and CD23, respectively, in gravity-stressed lymphocytes.

BACKGROUND: Recent studies have shown that gravity-changing stress modulates expression levels of cell surface molecules on human lymphocytes. However, previous in vitro microgravity studies have been performed with lymphocytes treated with mitogenic agents. HYPOTHESIS: The aim of the study was to test if exposure of cells to gravity-changing stress alone alters the expression levels of cell surface molecules. Specifically, we examined whether the expression of activation markers is altered after exposure of lymphocytes to combinations of microgravity and hypergravity. METHODS: We used free-fall in parabolic flight for human subjects and a drop-shaft to expose peripheral blood mononuclear cells (PBMC) to gravity-changing stress. After such exposure, PBMC were isolated, and expression levels of CD69, CD23 and CD38 were estimated using three-color flow cytometry. RESULTS: Increased percentages of CD69-positive cells were observed with PBMC from 3 of 4 volunteers who undertook 10 parabolic flights. Exposure of blood to gravity-changing stress in the drop-shaft increased both ratios of CD69-positive cells and levels of CD69 expression on T and B cells. In contrast, the percentages of CD23-positive B cells was decreased. However, gravity-changing stress was not always followed by significant alteration in CD38 expression. CONCLUSIONS: Our findings suggest that CD69 and CD23 might be useful markers that are up- and down-regulated, respectively, after exposure of lymphocytes to gravity-changing stress.

Reaction-diffusion theory in the presence of an attractive harmonic potential.

Problems involving the capture of a moving entity by a trap occur in a variety of physical situations, the moving entity being an electron, an excitation, an atom, a molecule, a biological object such as a receptor cluster, a cell, or even an animal such as a mouse carrying an epidemic. Theoretical considerations have almost always assumed that the particle motion is translationally invariant. We study here the case when that assumption is relaxed, in that the particle is additionally subjected to a harmonic potential. This tethering to a center modifies the reaction-diffusion phenomenon. Using a Smoluchowski equation to describe the system, we carry out a study which is explicit in one dimension but can be easily extended for arbitrary dimensions. Interesting features emerge depending on the relative location of the trap, the attractive center, and the initial placement of the diffusing particle.