Low density lipopolyprotein inhibits flavivirus acquisition in Aedes aegypti.

Aedes aegypti is the primary vector of a number of human pathogens including dengue virus (DENV) and Zika virus (ZIKV). Ae. aegypti acquires these viruses during the processing of bloodmeals obtained from an infected vertebrate host. Vertebrate blood contains a number of factors that have the potential to modify virus acquisition in the mosquito. Interestingly, low density lipopolyprotein (LDL) levels are decreased during severe DENV infection. Accordingly, we hypothesized that LDL is a modifiable factor that can influence flavivirus acquisition in the mosquito. We found that LDL is endocytosed by Ae. aegypti cells in a dynamin-dependent manner. LDL is also endocytosed by midgut epithelial cells and accumulates at the luminal midgut epithelium during bloodmeal digestion. Importantly, pretreatment with LDL, but not high density lipopolyprotein (HDL), significantly inhibited both DENV and ZIKV infection in vitro, and LDL inhibited ZIKV infection in vivo. This study identifies human LDL or 'bad cholesterol' as a modifiable factor that can inhibit flavivirus acquisition in Ae. aegypti. Identification of modifiable blood factors and critical cellular interactions that mediate pathogen acquisition may lead to novel strategies to disrupt the transmission cycle of vector-borne diseases.

Achieving a narrow size distribution of Au particles at a precise depth in SiO2 by segregation of Au precipitates.

We propose a new method of confining Au nanoparticles of a narrow size distribution at a precise depth in an SiO2 matrix. The process involves the formation of nanocavities in silicon by hydrogen implantation and annealing (at 850 degrees C), followed by Au gettering to and precipitation in such cavities and a wet oxidation at 900 degrees C. Starting with a silicon-on-insulator wafer, Au precipitates can be segregated behind a growing Si/SiO2 interface during wet oxidation and ultimately trapped in SiO2 at the front interface of a buried oxide layer. The shape of the precipitates has been examined by transmission electron microscopy and found to be spherical. The average diameters of these precipitates before and after oxidation have been determined as around 15 nm and 30 nm, respectively.

Replication and assembly of human papillomaviruses.

Human papillomaviruses (HPVs) are small dsDNA tumor viruses, which are the etiologic agents of most cervical cancers and are associated with a growing percentage of oropharyngeal cancers. The HPV capsid is non-enveloped, having a T=7 icosahedral symmetry formed via the interaction among 72 pentamers of the major capsid protein, L1. The minor capsid protein L2 associates with L1 pentamers, although it is not known if each L1 pentamer contains a single L2 protein. The HPV life cycle strictly adheres to the host cell differentiation program, and as such, native HPV virions are only produced in vivo or in organotypic "raft" culture. Research producing synthetic papillomavirus particles--such as virus-like particles (VLPs), papillomavirus-based gene transfer vectors, known as pseudovirions (PsV), and papillomavirus genome-containing quasivirions (QV)--has bypassed the need for stratifying and differentiating host tissue in viral assembly and has allowed for the rapid analysis of HPV infectivity pathways, transmission, immunogenicity, and viral structure.

Developing public health management training capacity in Nicaragua.

The Cooperative for Assistance and Relief Everywhere (CARE) and Centers for Disease Control and Prevention (CDC) Health Initiative in Nicaragua is distinctive in its focus on developing a cadre of in-country trainers whose aim is to equip frontline public health managers with widely applicable tools and techniques to assist them in identifying and solving implementation problems. Since 1999, 137 trainees--37% more than originally planned--have demonstrated competence by completing and presenting applied management projects. Nineteen professors from the preventive medicine faculty at the Autonomous University of Nicaragua also have been trained. The country office now has a cadre of seasoned trainers who can meet the ongoing management training needs of CARE staff and their counterparts in the Ministry of Health and in other nongovernmental organizations.

Risks of complication following thyroidectomy.

OBJECTIVE: Because hypoparathyroidism is a serious complication of thyroidectomy, we attempted to elucidate factors determining the risk of this postoperative outcome. SETTING: Four tertiary care hospitals in Albuquerque, New Mexico. PATIENTS: A retrospective study of 142 patients who underwent total or subtotal thyroidectomy between 1988 and 1995. MEASUREMENTS AND MAIN RESULTS: Permanent hypoparathyroidism was defined as hypocalcemic symptoms plus a requirement for oral vitamin D or calcium 6 months after thyroidectomy. Factors analyzed to determine their contribution to the risk of persistent postoperative hypoparathyroidism were the indication for thyroidectomy, performance of a preoperative thyroid needle biopsy, type of surgery, postoperative pathology, presence and stage of thyroid carcinoma, resident surgeon involvement, and specialty of the surgeon performing the procedure. Surgical specialty and stage of thyroid carcinoma were independent risk factors for persistent postoperative hypoparathyroidism by multivariate analysis. Nine (29%) of 31 patients who had thyroidectomy by otolaryngologists met criteria for permanent hypoparathyroidism, and 6 (5%) of 111 patients who had thyroidectomy by general surgeons met the same criteria (p < .001). Adjustment for the effect of stage did not eliminate the effect of specialty (p = .006), and adjustment for the effect of specialty did not eliminate the effect of stage (p = .02), on the occurrence of postoperative hypoparathyroidism. CONCLUSIONS: We conclude from our data that patients undergoing thyroidectomy by an otolaryngologist may be at a higher risk of permanent postoperative hypoparathyroidism than patients who undergo thyroidectomy by a general surgeon. This may reflect differences in case selection or surgical approach or both.

Electrical tinnitus suppression: frequency dependence of effects.

Electrical stimulation through a round window electrode has been evaluated in 9 patients with unilateral deafness and severe tinnitus. Three subjects were permanently implanted with positive long lasting results. Analysis of the threshold of sound perception, tinnitus suppression and auditory discomfort levels as a function of current frequency revealed the advantage of low frequency stimulation. In 2 patients the loudness of electrically evoked sound perception was balanced against tones in the hearing ear. Our results can be interpreted as indicating that processes other than auditory masking are responsible for electrical tinnitus suppression.

Purification and characterization of Epstein-Barr virus gp340/220 produced by a bovine papillomavirus virus expression vector system.

Our initial results with a bovine papilloma virus (BPV) vector expression system indicated that we could produce significant amounts of Epstein-Barr virus (EBV) gp340/220 in the supernatant of a mouse fibroblast cell line. We have now extended these findings to show that the truncated version of gp340/220, where the membrane anchor sequence is deleted, is produced even after extended passage of the cells, at a level of approximately 1 mg/4 x 10(8) cells. A simple purification protocol using Sephacryl S300HR and gelatin agarose gives a product which is greater than 90% pure. This product is recognized by anti-gp340 monoclonal antibodies from five different epitope groups and induces antibody that recognizes the authentic gp340/220 and neutralizes EBV in vitro. The purified gp340/220 can be used in ELISA and stimulates the proliferation of T-cell clones specific for gp340/220. These characteristics, together with the fact that BPV-transformed lines have been utilized for the production of pharmaceuticals for use in humans, suggest that this gp340/220 is suitable as a source of antigen for vaccination to prevent EBV infection and related diseases.

Diagnosis of nasopharyngeal carcinoma by means of recombinant Epstein-Barr virus proteins.

The immune response of patients with nasopharyngeal carcinoma to Epstein-Barr virus (EBV) antigens is diagnostic of the tumour. Existing tests use EBV antigens produced in EBV-infected lymphoblastoid cells, but the virus replicates poorly in these cells. Serum samples from 18 patients diagnosed as having nasopharyngeal carcinoma were screened by western blot analysis, enzyme-linked immunosorbent assay (ELISA), and immunofluorescence tests for antibodies to the EBV-coded alkaline deoxyribonuclease (DNase), thymidine kinase, and membrane antigen (gp340/220) produced in recombinant baculovirus or bovine papillomavirus systems. Each protein was a useful diagnostic marker for nasopharyngeal carcinoma, although in the gp340/220 ELISAs there was substantial overlap for both IgG and IgA antibodies between serum samples from nasopharyngeal carcinoma patients and those from healthy donors seropositive for EBV. The EBV thymidine kinase was the most sensitive predictor of nasopharyngeal carcinoma; all such samples showed both IgG and IgA antibody responses to this protein and all gave clearly distinct titres from those of the EBV-seropositive donors in the IgA test. Each of the recombinant systems described is suitable for use in large-scale screening programmes for the early diagnosis of nasopharyngeal carcinoma.

How people power fuels a high-flying carrier.

America West Airlines, in operation for only seven years, has grown to become the country's eleventh largest carrier. The key to the organization's growth has been its ability to forge an unusually strong bond between management and employees.

Characterization and expression of a glycoprotein encoded by the Epstein-Barr virus BamHI I fragment.

Computer-assisted analysis of the Epstein-Barr virus (EBV) open reading frame BILF2 (B95-8 nucleotides 150,525 to 149,782) predicts that it codes for a membrane-bound glycoprotein. [3H]glucosamine labeling of cells infected with vaccinia virus recombinants that expressed the BILF2 open reading frame revealed several diffuse species of glycoproteins of around 80,000 and 55,000 daltons. A monoclonal antibody derived from spleens of mice immunized with EBV immunoprecipitated the EBV-derived protein made by the vaccinia virus recombinants and also precipitated a late envelope glycoprotein with a mobility of 78,000 to 55,000 from EBV-producing cells. N-Glycanase treatment of the immunoprecipitated BILF2 product from EBV-producing cells resulted in a polypeptide of 28 kilodaltons, closely agreeing with the predicted molecular mass for the unmodified BILF2 gene product. Western (immuno-) blots using recombinant infected cells as a source of antigen showed that the majority of EBV-seropositive individuals have a serum antibody response to the BILF2-encoded gp78/55.

Electrical tinnitus suppression (ETS) with a single channel cochlear implant.

Patients with intractable tinnitus in a dead ear were selected for electrical tinnitus suppression (ETS) first with a round window electrode inserted via the ear canal. Three patients have been selected for implantation with a UCH/RNID single channel extracochlear device to use with a sinusoidal tinnitus suppressor. We have also examined the effect of sinusoids on deafened implantees with tinnitus and conclude that tinnitus can be suppressed in some individuals with low frequency sine waves. Two patients are presented who have used cochlear implants to suppress their tinnitus for more than 18 months.

Design of the UCH/RNID cochlear implant system.

This paper describes the design of the UCH/RNID single channel, extracochlear, auditory prosthesis. The system employs a body-worn analogue sound processor whose output is transmitted to a pair of implanted Platinum/Iridium stimulating electrodes via a transcutaneous inductively coupled link. The stimulating current is passed between a 1 mm diameter ball electrode, resting in the round window, and a 5 mm square foil electrode placed under the temporalis muscle. The implanted amplitude modulation receiver circuit is fabricated from hermetically sealed electronic components which are mounted on a ceramic substrate. The implanted circuit is encapsulated in silicone rubber. The primary design objective was to produce a reliable and effective auditory prosthesis costing less than 1,000 pounds.

Gallstones and risk of gallbladder cancer.

The relationship between gallstones and gallbladder cancer was investigated in a case-control study in 131 subjects with gallbladder cancer and 2,399 subjects without gallbladder cancer. Included in the study were male and female subjects from 3 racial groups: white, black, and Southwestern American Indian. For the non-Indian group there was a significant relationship between gallstones and gallbladder cancer, with an overall estimated relative risk (RR) of 4.4 (95% confidence interval, 2.6-7.3). For the Indian population the overall estimated RR was much higher: RR = 20.9; 95% confidence interval = 8.1-54. By the combination of the RR, the prevalence of gallstones, and the overall incidence of gallbladder cancer, the risk of gallbladder cancer was calculated in each population for subjects with untreated gallstones. In older subjects with gallstones the estimated 20-year cumulative risk for gallbladder cancer ranged from 0.13% in black males to 1.5% in Indian females. It was concluded that the risk of gallbladder cancer in untreated subjects with gallstones is heterogeneous, depending on race and sex as well as the period of exposure to gallstones.

Identification of sensory neural hearing loss in very preterm infants by brainstem auditory evoked potentials.

Brainstem auditory evoked potentials were recorded in 117 newborn infants of less than 33 weeks of gestation. The potentials were absent in 10 infants (bilaterally in eight and unilaterally in two) and present in 107. By 1 year of age nine of the 10 infants with absent brainstem auditory evoked potentials were shown to have sensory neural hearing loss and required hearing aids: the remaining infant had secretory otitis media. None of the 107 infants whose auditory evoked potentials were present were found to have sensory neural hearing loss but 13 had secretory otitis media. Measurement of brainstem auditory evoked potentials is an accurate method of identifying sensory neural hearing loss in very preterm infants.

Language development in a group of very low-birth-weight children whose postauricular myogenic response was tested in infancy.

A new instrument for the detection of the postauricular myogenic (PAM) response was used to test the hearing of 106 infants weighing less than or equal to 1,500 g when they were aged 1 to 21 months. Eighty-eight infants showed a positive response at 60 dB hearing level (HL) (normal). The other 18 did not respond; four were found to have sensory neural hearing loss and another six had conductive loss due to secretory otitis media. Of the 106 children, 90 aged 2 years or more (mean 27 months) were living in the United Kingdom, and their language development was assessed. It was normal in 67/75 children whose PAM response had been normal in infancy. The remaining eight children with normal PAM responses in infancy, had language delay. All eight children had problems that were thought to account for the delay, including three with mental retardation, three with cerebral palsy, and two whose families did not speak English. Language development was normal in 11/15 children tested whose PAM responses had been found to be abnormal, including all six whose secretory otitis media had been diagnosed and treated at the time of the PAM test. Delay in language development was found in 3/4 children with sensory neural hearing loss who were available for testing and in one child with overall developmental delay. It is concluded that a positive PAM response at 60 dB HL in infancy indicated hearing adequate for the development of normal speech in otherwise normal children among a group of infants at high risk of hearing loss.

Exercise lowers thyroid radioiodine uptake: concise communication.

The effect of exercise upon the uptake of radioiodine by the thyroid was examined in both rats and humans. Rats that exercised intermittently on a mechanical wheel for a period of 20 days had significantly lower uptake values (p < 0.0001) than sedentary controls. Human volunteers that ran at least ten miles/week had a lower mean 24-hr uptake value (8.0 +/- 2.8%) than nonexercising subjects (14.3 +/- 5.1%, p < 0.01). Other thyroid function studies (thyroxine, triiodothyronine, triiodothyronine resin uptake, thyroid-stimulating hormone) did not differ significantly between the exercising and nonexercising groups. These studies suggest that exercise significantly alters thyroid iodine economy.