Enhanced Charge Collection in MOF-525-PEDOT Nanotube Composites Enable Highly Sensitive Biosensing

With the aim of a reliable biosensing exhibiting enhanced sensitivity and selectivity, this study demonstrates a dopamine (DA) sensor composed of conductive poly(3,4-ethylenedioxythiophene) nanotubes (PEDOT NTs) conformally coated with porphyrin-based metal-organic framework nanocrystals (MOF-525). The MOF-525 serves as an electrocatalytic surface, while the PEDOT NTs act as a charge collector to rapidly transport the electron from MOF nanocrystals. Bundles of these particles form a conductive interpenetrating network film that together: (i) improves charge transport pathways between the MOF-525 regions and (ii) increases the electrochemical active sites of the film. The electrocatalytic response is measured by cyclic voltammetry and differential pulse voltammetry techniques, where the linear concentration range of DA detection is estimated to be 2 × 10-6-270 × 10-6 m and the detection limit is estimated to be 0.04 × 10-6 m with high selectivity toward DA. Additionally, a real-time determination of DA released from living rat pheochromocytoma cells is realized. The combination of MOF5-25 and PEDOT NTs creates a new generation of porous electrodes for highly efficient electrochemical biosensing.

Benign prostatic enlargement is not associated with diabetes: a population-based study

The association between diabetes and benign prostatic hyperplasia remains inconclusive. In this case-control study, we examined the association of diabetes with benign prostatic enlargement (BPE) using the Longitudinal Health Insurance Database 2000 in Taiwan. In total, 20 152 patients with BPE as cases and 20 152 age-matched patients without BPE were included as controls. Conditional logistic regression analyses were performed to calculate the odds ratio (OR) and corresponding 95% CI for having been previously diagnosed with diabetes between cases and controls. We found that of the 40 304 sampled patients, 9492 (23.6%) had a history of diabetes before the index date. This mean age for the sampled patients was 65.9 with a standard deviation of 12.0 years. A Chi-squared test revealed that there was a significant difference in the prevalence of prior diabetes between cases and controls (25.3% vs. 21.8%, p < 0.001). The conditional logistic regression found that the OR of prior diabetes for cases was 1.21 (95% CI = 1.15-1.27) compared with controls. However, after adjusting for geographic region, monthly income, urbanization level, hypertension, coronary heart disease (CHD), hyperlipidemia, tobacco use disorder, and obesity, the association between prior diabetes and BPE did not reach a statistically significant level (OR = 1.03, 95% CI = 0.98-1.08). In addition, it was noteworthy that hypertension (OR = 1.25, 95% CI = 1.20-1.31), CHD (OR = 1.40, 95% CI = 1.32-1.48), and hyperlipidemia (OR = 1.30, 95% CI = 1.24-1.36) were all significantly associated with BPE. We found that men with a diagnosis of diabetes were not significantly associated with BPE after adjusting for patient's sociodemographic characteristics and comorbidities.

A novel flow cytometric analysis for platelet activation on immobilized von Willebrand factor or fibrillar collagen

Under flow conditions, platelets adhere singly or in small aggregates on von Willebrand factor (VWF)-coated surfaces, but form large aggregates on immobilized fibrillar collagen. We developed a novel flow cytometric analysis to study the mechanisms underlying these distinct platelet deposition patterns. Flow cytometry was used to measure platelet activation after platelet adherence onto microspheres coated with either VWF or collagen fibrils. Two representative indices were calculated to quantify activated GpIIb-IIIa and P-selectin expression on adherent platelets. The signaling pathways responsible for platelet activation after interacting with fibrillar collagen were elucidated using various inhibitors. An in vitro endothelial cell wound model was also used to study the roles of VWF and fibrillar collagen in platelet deposition onto subendothelial matrixes. The adherent platelets on fibrillar collagen express more activated GpIIb-IIIa and P-selectin than those on VWF. Activation of GpIIb-IIIa and expression of P-selectin after platelet interaction with collagen occur via different intracellular signaling pathways; however, Ca2+ released from intracellular pools is common to both phenomena. Platelets were deposited singly or formed small aggregates on the endothelial cell wounded area, and this deposition pattern was dependent on VWF molecules secreted by endothelial cells and the absence of subendothelial collagen fibrils. As less activated GpIIb-IIIa and P-selectin are expressed after platelets interact with immobilized VWF alone, subsequent flowing platelet recruitment is minimal. Collagen fibrils, however, can activate adherent platelets sufficiently to promote the formation of large platelet aggregates.

The human immunodeficiency virus type 1 accessory protein Vpu induces apoptosis by suppressing the nuclear factor kappaB-dependent expression of antiapoptotic factors

Human immunodeficiency virus (HIV) type 1 Vpu is an integral membrane protein with a unique affinity for betaTrCP (TrCP), a key member of the SkpI-Cullin-F-box E3 ubiquitin ligase complex that is involved in the regulated degradation of cellular proteins, including IkappaB. Remarkably, Vpu is resistant to TrCP-mediated degradation and competitively inhibits TrCP-dependent degradation of IkappaB, resulting in the suppression of nuclear factor (NF)-kappaB activity in Vpu-expressing cells. We now report that Vpu, through its interaction with TrCP, potently contributes to the induction of apoptosis in HIV-infected T cells. Vpu-induced apoptosis is specific and independent of other viral proteins. Mutation of a TrCP-binding motif in Vpu abolishes its apoptogenic property, demonstrating a close correlation between this property of Vpu and its ability to inhibit NF-kappaB activity. The involvement of NF-kappaB in Vpu-induced apoptosis is further supported by the finding that the levels of antiapoptotic factors Bcl-xL, A1/Bfl-1, and TNF receptor-associated factor (TRAF)1, all of which are expressed in an NF-kappaB-dependent manner, are reduced and, at the same time, levels of active caspase-3 are elevated. Thus, Vpu induces apoptosis through activation of the caspase pathway by way of inhibiting the NF-kappaB-dependent expression of antiapoptotic genes.

Human immunodeficiency virus type 1 Vif protein is packaged into the nucleoprotein complex through an interaction with viral genomic RNA

The human immunodeficiency virus type 1 (HIV-1) Vif protein plays a critical role in the production of infectious virions. Previous studies have demonstrated the presence of small amounts of Vif in virus particles. However, Vif packaging was assumed to be nonspecific, and its functional significance has been questioned. We now report that packaging of Vif is dependent on the packaging of viral genomic RNA in both permissive and restrictive HIV-1 target cells. Mutations in the nucleocapsid zinc finger domains that abrogate packaging of viral genomic RNA abolished packaging of Vif. Additionally, an RNA packaging-defective virus exhibited significantly reduced packaging of Vif. Finally, deletion of a putative RNA-interacting domain in Vif abolished packaging of Vif into virions. Virion-associated Vif was resistant to detergent extraction and copurified with components of the viral nucleoprotein complex and functional reverse transcription complexes. Thus, Vif is specifically packaged into virions as a component of the viral nucleoprotein complex. Our data suggest that the specific association of Vif with the viral nucleoprotein complex might be functionally significant and could be a critical requirement for infectivity of viruses produced from restrictive host cells.

Functional interaction between the cytoplasmic leucine-zipper domain of HIV-1 gp41 and p115-RhoGEF

The long cytoplasmic tail of the human immunodeficiency virus (HIV)-1 transmembrane protein gp41 (gp41C) is implicated in the replication and cytopathicity of HIV-1 [1]. Little is known about the specific functions of gp41C, however. HIV-1 or simian immunodeficiency virus (SIV) mutants with defective gp41C have cell-type- or species-dependent phenotypes [2] [3] [4] [5] [6]. Thus, host factors are implicated in mediating the functions of gp41C. We report here that gp41C interacted with the carboxy-terminal regulatory domain of p115-RhoGEF [7], a specific guanine nucleotide exchange factor (GEF) and activator of the RhoA GTPase, which regulates actin stress fiber formation, activation of serum response factor (SRF) and cell proliferation [8] [9]. We demonstrate that gp41C inhibited p115-mediated actin stress fiber formation and activation of SRF. An amphipathic helix region with a leucine-zipper motif in gp41C is involved in its interaction with p115. Mutations in gp41C leading to loss of interaction with p115 impaired HIV-1 replication in human T cells. These findings suggest that an important function of gp41C is to modulate the activity of p115-RhoGEF and they thus reveal a new potential anti-HIV-1 target.

A single dose of the ovotoxicant 4-vinylcyclohexene diepoxide is protective in rat primary ovarian follicles

Repeated dosing of rats with the ovotoxic chemical, 4-vinylcyclohexene diepoxide (VCD), destroys primordial and primary ovarian follicles via apoptosis (physiological cell death) by accelerating the normal rate of atresia. The present study investigated the effect of a single dose (1x) of VCD. Immature (d28) female Fischer 344 rats were dosed 1x or 15x with VCD (80 mg/kg ip). Ovaries were collected 24 h or 15 days following 1x VCD or after 15x for classification and evaluation. Following 1x VCD the number of healthy primary follicles was greater (p < 0.05) than control 24 h and 15 days later. This effect reflected a slowing of the normal rate of atresia seen in control ovaries. There was no effect of a single dose on primordial or growing follicles at any time. Expression of mRNA encoding the cell death gene bax was reduced (p < 0.05) on d1 after 1x VCD in isolated primordial and primary follicles. These observations were in contrast to a decreased (p < 0. 05) number of healthy primary and primordial follicles in ovaries and increased (p < 0.05) bax mRNA in isolated follicles from rats dosed 15x for 15 days. Immunofluorescence staining revealed that, the distribution of Bax protein was similar between ovaries from controls and 1x or 15x VCD-treated rats. These data provide evidence for a "protective" response against the normal rate of atresia in primary ovarian follicles following exposure to 1x VCD. Additionally, changes in expression of bax mRNA paralleled alterations in the rate of atresia.

Underreporting and misclassification of maternal mortality in Taiwan

BACKGROUND

Underreporting and misclassification of maternal deaths are universal. The purposes of this study were to quantify the level of underestimation of maternal mortality and to analyze possible factors that contribute to underreporting and misclassification of maternal mortality.

METHODS

An interview census of all registered deaths that occurred during 1984-1988 in women of reproductive age was undertaken in Taiwan. Pregnancy-related deaths were screened from all collected questionnaires and death certificates by the researchers. The screened pregnancy-related deaths were then reviewed and evaluated by obstetrician-gynecologists; a cause of each death was assigned.

RESULTS

For the five years, on average, the rate of underreporting of maternal mortality is 58.38% and the correct/confirmed rate of classification is 53.28%. Underreported and misclassified maternal deaths are more likely for women aged 20-24, with stillbirth and fetal death, care sought for non-obstetric reasons, care received in private hospitals and clinics, occurrence in the home, certification by non-obstetrician-gynecologists and court doctors, and death from non-obstetric causes.

CONCLUSIONS

This study shows the limitations of official vital registration and concludes that dependence on death certificates alone to identify maternal deaths is incomplete and incorrect.

Mitochondrial deoxyribonucleic acid 4977-bp deletion is associated with diminished fertility and motility of human sperm

The accumulation of mitochondrial DNA (mtDNA) mutations has been suggested to be an important contributor to human aging and degenerative diseases. In previous studies, we found an age-dependent increase of mtDNA mutations in various human tissues. Sperm motility is one of the determinants of male fertility. The possible relationship between mtDNA deletions and diminished fertility and motility of sperm was explored in the present study. We examined accumulation of the 4977-bp mtDNA deletion in spermatozoa obtained from patients with infertility or subfertility and compared these values with those of normal individuals. Using polymerase chain reaction (PCR) techniques, we determined the frequency of occurrence and the proportion of mtDNA with the 4977-bp deletion in human spermatozoa with different motilities. Human spermatozoa were separated by self-migration in Percoll gradients into five fractions with different motility scores. The highest frequency of occurrence of the 4977-bp mtDNA deletion was found in sperm in the fraction with the lowest motility. The results revealed a negative correlation between sperm motility and the proportion of 4977-bp-deleted mtDNA. Furthermore, we found a significantly higher incidence of the 4977-bp mtDNA mutation in patients with asthenospermia, oligospermia, and primary infertility compared to normal individuals. These findings suggest that mtDNA mutations may play an important role in some pathophysiological conditions in human spermatozoa.

The greater omentum transplantation model in the rat

Dissection of the rat omentum were performed to study the feasibility of rat omental free transfer. The right epiploic vessels were found to be adequate for anastomosis in transfer. Twelve omental free flaps were transferred to the groin, with 100% survival of flaps in the 10 animals that survived the operation. The artery and vein averaged 0.3 and 0.4 mm in diameter, respectively. The average pedicle length was 5 mm, and the average flap weight was 136.9 mg. This omental transplant offers a new experimental means of studying lymphedema, neovascularization, and tissue revascularization.

Microvascular transfer of the rectus abdominis muscle and myocutaneous flap in rats

A rat microvascular free rectus myocutaneous flap model with a superior epigastric vessel pedicle is presented. The rectus muscle has a predictable "flow-through" axial vascular system consisting of superior and inferior epigastric vessels anastomosing under the fascial sheath, and six to seven musculocutaneous perforating branches to the skin. The superior epigastric artery and vein, averaging 0.45 mm and 0.5 mm in diameter, can be used as the vascular pedicle in muscle or myocutaneous flap transplantation. Eight muscle and 15 myocutaneous flaps were transplanted to the groin. The myocutaneous flaps averaged 3.5 cm by 1.2 cm in size; the pedicle length averaged 11 mm. The 5 day survival was 100% for muscle flaps and 67% for myocutaneous flaps. The rectus myocutaneous flap is believed to be the first true myocutaneous model in the rat.