Filamentous tau in oligodendrocytes and astrocytes of transgenic mice expressing the human tau isoform with the P301L mutation

We recently reported a transgenic mouse line (JNPL3) that expresses mutant (P301L) tau and develops neurofibrillary tangles composed of filamentous tau aggregates. Here we show that these mice have abnormal tau filaments not only in neurons, but also in oligodendrocytes and astrocytes. Similar results were detected in another transgenic line (JNPL2+3+) that expresses the longest human tau isoform with the P301L mutation. The ultrastructure of the tau filaments and immunoreactivity with tau and ubiquitin antibodies were similar in glia and neurons. Given similarities of the lesions in the mice to human neuronal and glial inclusions, these transgenic mice appear to be a valuable model to study pathogenesis of the neurodegenerative tauopathies.     

Expression of interleukin-18 by nasopharyngeal carcinoma cells: a factor that possibly initiates the massive leukocyte infiltration

Interleukin-18 (IL-18) is a single-chain cytokine that is produced by various cells. With interleukin-12 (IL-12), it synergistically stimulates activated T cells and natural killer (NK) cells to produce interferon-gamma (IFN-gamma). Nasopharyngeal carcinoma (NPC) is the most common form of nasal and nasopharyngeal malignancy, and in NPC tumor tissues there is an intense leukocyte infiltration comprising predominantly T cells and macrophages. We previously showed an increased expression of IFN-gamma in the infiltrating T cells. To identify the cells that provide IL-12 and IL-18 for stimulating the expression of IFN-gamma in activated T cells, NPC cell lines CNE-2 and HK-1, as well as biopsies obtained from NPC and control individuals, were examined. CNE-2 and HK-1 cells were found to express messenger RNA encoding IL-18, but not IL-12. Secreted IL-18 was detected in the culture supernatant. Addition of a caspase-1 inhibitor decreased the secretion level, indicating that this IL-18 secretion was caspase-1 dependent. Moreover, the in vitro IL-18 production in NPC cell lines correlated with the NPC tumor cells in situ. NPC tumor cells in the biopsies produced IL-18, as detected by immunohistochemistry and immunofluorescent double staining. In contrast, IL-18 expression was not observed in the control biopsies. We suggest that IL-18 secreted by NPC tumor cells plays a role in initiating the leukocyte infiltration process. IL-18 stimulates T cells and NK cells to produce IFN-gamma, which consequently activates macrophages and other immune cells to secrete chemokines to start a leukocyte recruitment cascade.     

Analysis of the influence of therapy and viral suppression on high-risk sexual behaviour and sexually transmitted infections among patients infected with human immunodeficiency virus in Taiwan

This study examined the effects of certain characteristics of human immunodeficiency virus (HIV)-infected patients related to the risks of practising unprotected sex (UPS) among 919 HIV-infected patients who attended the sexually transmitted disease (STD) clinic of the Taipei City STD Control Center, Taiwan, during the period January–July 2004. After learning that they were HIV-positive, 517 (56%) subjects had practised UPS, 476 (52%) had a new STD diagnosis, and 106 (12%) had used some form of injected drug. UPS was reported by 76% of homosexual/bisexual males, 19% of heterosexual males and 5% of females, and was reported more often by those individuals with casual sexual partners (p < 0.001). According to multivariate logistic regression analyses, UPS was associated with male-tomale sexual intercourse (OR 2.46; 95% CI 1.26–4.86, p < 0.001), with casual sexual partners (OR 2.82; 95% CI 1.62–4.88, p < 0.001), and with an individual's knowledge of his/her HIV status for > 11 years (OR 2.06; 95% CI 1.02–4.18, p < 0.05). Although using anti-retroviral therapy to prevent sexual transmission of HIV is rational, the avoidance of at-risk sexual behaviour should also be a priority among HIV-seropositive individuals. Ongoing risk-reduction counselling related to HIV transmission is needed to reduce certain sexual behaviours associated with HIV transmission.     

Pregnancy following treatment of symptomatic myomas with laparoscopic bipolar coagulation of uterine vessels

BACKGROUND: Laparoscopic bipolar coagulation of uterine vessels (LBCUV) has been employed for women with symptomatic uterine myomas, but its effect on subsequent pregnancy has not been characterized. METHODS: Four-hundred and twenty-three women entered the study between March 1999 and December 2001. Of these, 142 women (33.6%) were under the age of 40 years at the time of LBCUV, 36 of whom (36/142, 25.3%) were sexually active without contraception. In a prospective study of 142 patients (<40 years old) undergoing LBCUV for symptomatic myomas, 15 women became pregnant (17 total pregnancies) and were evaluated by physical and ultrasound examinations. RESULTS: The volume of the dominant myoma was 117.4 +/- 118.4 and 36.8 +/- 56.8 cm(3) before and after LBCUV respectively. Volume of the dominant myoma after pregnancy was 46.2 +/- 76.7 cm(3) (mean +/- SD). There was a significant difference in myoma volume before and after LBCUV (P = 0.002), but no significant difference in myoma volume when comparing post-partum size with post-LBCUV size (P = 0.269). Pregnancy outcomes included seven miscarriages in the first trimester and one premature rupture of membrane (PPROM). Although the other pregnancies were regarded as uncomplicated, only two women were delivered of normal neonates as the other seven pregnancies were terminated secondary to patient request. CONCLUSIONS: The pregnancy and term pregnancy rates in sexually active women without contraception were 41.6% (15/36) and 5.6% (2/36) respectively. Because a relatively high rate (7/17, 41.2%) of early miscarriages was observed, we recommend that this procedure be employed only for women who do not desire additional children.     

Tau assembly in inducible transfectants expressing wild-type or FTDP-17 tau

Conditional expression systems for 4-repeat wild-type (WT) tau or the corresponding mutants V337M and R406W were established in human neuroglioma H4 cells to study the effect of tau mutations on the physicochemical properties of tau, and to develop a cellular model for the formation of filamentous tau characteristic of frontotemporal dementia with parkinsonism linked to chromosome 17 (FTDP-17) and Alzheimer's disease. Upon induction tau expression increased, reaching maximal levels at 5 to 7 days. WT tau was phosphorylated at amino acids T181, S202/T205, T231, and S396/S404. The R406W mutation decreased tau phosphorylation at each of these sites as did the V337M mutation except for S396/S404 sites that increased. Most tau in postnuclear cell lysates was recovered in the supernatant fraction after centrifugation at 200,000 x g. The amount of tau in the pellet fraction increased more in mutant transfectants compared to WT when the induction was extended beyond 5 days. This particulate tau could be partially extracted with salt, Triton X-100, or sarkosyl. Of the transfectants, R406W had the highest proportion of sarkosyl-insoluble tau by day 7. This insoluble fraction was thioflavin S-positive and contained 15- to 5-nm-wide filaments with tau immunoreactivities. The R406W filaments were more abundant than those detected in similar preparations from WT or V337M transfectants. At the light microscopy level, most tau was found with microtubules, or diffusely distributed in the cytoplasm, but none of this appeared thioflavin S-positive. The results suggest that conditional tau transfectants are in a pretangle stage making them an attractive model system for studying intracellular tangle accumulation and for testing potential therapeutic agents as inhibitors for tau aggregation.     

The Effects of “Immunosympathectomy” on Blood Pressure and Vascular “Reactivity” in Normal and Spontaneously Hypertensive Rats

Newborn litters of spontaneously hypertensive rats (SHR) and normotensive control rats (NCR) were identically treated with sympathetic nerve growth factor antiserum (Wellcome) which markedly interferes with adrenergic cardiovascular control (Zaimis 1967). Blood pressure, measured intermittently during 8 months, was in treated SHR (SHR_is) about 25 % higher than in NCR_is, their respective pressures being about 40 % and 25 % lower than those of sham-treated SHR and NCR.–The hindquarters of one SHR_is, or NCR_is, were then perfused at constant flow in parallel with those of ordinary NCR. Starting from maximal vasodilatation, resistance increases were induced by graded noradrenaline (NA) infusions, from “threshold” to maximal pressor responses. Compared to NCR_is, SHR_is showed an increased resistance at maximal dilatation, an increased slope of the NA dose-response curve and an increased maximal pressor response, while their NA “thresholds” did not differ significantly. Thus, the structurally determined hemodynamic differences between ordinary SHR and NCR (Folkow et al. 1970 b) characterize also SHR_is and NCR_is, though to a reduced extent. Even when comparing SHR_is with ordinary- NCR, which exhibited similar “resting” pressures, these differences partly remain, suggesting that the SHR resistance vessels might, for genetic reasons, be more prone to adapt structurally to pressure loads than those of NCR.     

On-line sensors for coagulation proteins: concept and progress report

The assessment of blood damage and of the activation of the coagulation, complement and/or inflammatory systems by cardiovascular and extracorporeal devices is difficult at best. Immunoassay methods are now available for the measurement of many of the proteins, enzymes and peptides involved in coagulation, thrombosis, complement and inflammation. We present a long-range project and plan to develop an array of remote, on-line, semicontinuous immunosensors for selected coagulation proteins, based on fluoroimmunoassay principles. The free/bound separation step is performed optically. Excitation of fluorescence is performed via an evanescent wave produced by total internal reflection and waveguide optics. Fluorescence emission is collected only in the near field. Means to deliver fluorescently-labelled reagent and to modify the antigen-antibody binding constant are presented and discussed. The results of non-specific binding, plasma-blood fluorescence, and blood compatibility are also discussed.     

Vancomycin-resistant enterococcal bacteremia: comparison of clinical features and outcome between Enterococcus faecium and Enterococcus faecalis.

BACKGROUND AND PURPOSE: Vancomycin-resistant enterococci (VRE) have emerged as important nosocomial pathogens. This study was conducted to clarify the clinical features and outcome of patients with vancomycin-resistant enterococcal bacteremia. METHODS: Patients with vancomycin-resistant enterococcal bacteremia treated at a medical center in northern Taiwan between November 1998 and July 2006 were reviewed. Clinical and bacteriological characteristics of Enterococcus faecium and Enterococcus faecalis were compared. RESULTS: Twelve patients (6 males and 6 females) were included for analyses. The mean age was 69.3 years (range, 40 to 86 years), and 8 cases (66.7%) were older than 65 years. All patients had underlying disease. Two patients received total hip replacement before development of VRE bacteremia. Twelve patients had prior exposure to broad-spectrum antimicrobial therapy. Ten patients had prior intensive care unit stay and prior mechanical ventilation before VRE bacteremia. All of the patients (n = 12) had an intravascular catheter in place. Bacteremia was caused by E. faecalis in 4 patients and by E. faecium in eight. The portals of entry included urinary tract (8.3%), skin, soft tissue and bone (41.7%) and unknown sources (50.0%). E. faecium showed a higher rate of resistance to ampicillin and teicoplanin than E. faecalis (87.5% vs 0.0%, p=0.01). The 60-day mortality rate was higher in patients with E. faecium bacteremia than E. faecalis bacteremia (62.5% vs 0.0%), although statistical significance was not obtained (p=0.08). CONCLUSIONS: VRE bacteremia may have an impact on the mortality and morbidity of hospitalized patients. Patients with bacteremia caused by vancomycin-resistant E. faecium had a grave prognosis, especially immunosuppressed patients. The prudent use of antibiotics and strict enforcement of infection control may prevent further emergence and spread of VRE.     

A genipin-crosslinked gelatin membrane as wound-dressing material: in vitro and in vivo studies

A naturally occurring crosslinking agent (genipin) was used in this study to crosslink gelatin hydrogel to develop a wound-dressing membrane. The study was to investigate the in vitro characteristics of the genipin-crosslinked gelatin membrane. The glutaraldehyde-crosslinked counterpart, at a similar crosslinking degree, was used as control. Additionally, an in vivo experiment was undertaken to study the wound healings covered with the glutaraldehyde- and genipin-crosslinked dressings in a rat model. The in vitro results obtained suggested that crosslinking of gelatin membranes with glutaraldehyde or genipin may produce distinct crosslinking structures. The differences in crosslinking structure can significantly affect the mechanical property, water-vapor-transmission rate, swelling ratio, degradation against enzyme and cellular compatibility of the crosslinked membranes. In the in vivo study, it was found that the degree of inflammatory reaction for the wound treated with the genipin-crosslinked dressing was significantly less severe than that covered with the glutaraldehyde-crosslinked dressing throughout the entire course of the study. Additionally, the healing rate for the wound treated with the genipin-crosslinked dressing was notably faster than its glutaraldehyde-crosslinked counterpart.     

The mouse Mid1 gene: implications for the pathogenesis of Opitz syndrome and the evolution of the mammalian pseudoautosomal region

We have recently reported isolation of the gene responsible for X- linked Opitz G/BBB syndrome, a defect of midline development. MID1 is located on the distal short arm of the human X chromosome (Xp22. 3) and encodes a novel member of the B box family of zinc finger proteins. We have now cloned the murine homolog of MID1 and performed preliminary expression studies during development. Mid1 expression in undifferentiated cells in the central nervous, gastrointestinal and urogenital systems suggests that abnormal cell proliferation may underlie the defect in midline development characteristic of Opitz syndrome. We have also found that Mid1 is located within the mouse pseudoautosomal region (PAR) in Mus musculus , while it seems to be X- specific in Mus spretus. Therefore, Mid1 is likely to be a recent acquisition of the M. musculus PAR. Genetic and FISH analyses also demonstrated a high frequency of unequal crossovers in the murine PAR, creating spontaneous deletion/duplication events involving Mid1. These data provide evidence for the first time that genetic instability of the PAR may affect functionally important genes. In addition, we show that MID1 is the first example of a gene subject to X-inactivation in man while escaping it in mouse. These data contribute to a better understanding of the molecular content and evolution of the rodent PAR.