Chlamydial elementary bodies are translocated on the surface of epithelial cells

Infection of eukaryotic cells by intracellular pathogens such as chlamydia requires attachment to the host cell surface. Chlamydia are thought to attach to the tips of microvilli in confluent monolayers of polarized cells. In vitro evidence obtained from migrating epithelial cells suggested that during healing the route of pathogen uptake might be different from that in intact epithelia. The small size of infectious chlamydial elementary bodies (approximately 0.3 microm in diameter) has made it difficult, however, to analyze the early stages of pathogen-host cell interaction in living cells by conventional microscopy. Contrast-enhanced video microscopy was therefore used to examine the earliest events of host-pathogen interaction and test the hypothesis that chlamydial uptake into the healing epithelia can involve translocation over the host cell surface. Observations made in this way were validated by scanning and immunofluorescence microscopy. These studies revealed two fates for chlamydiae taken onto the lamellipodial surface: 1) some chlamydiae were moved in a random fashion on the cell surface or were detached into the culture medium, whereas 2) other chlamydiae were translocated across the lamellipodium in a highly directed manner toward the microvillous perinuclear region. After internalization, these latter chlamydiae were found within intracellular inclusions, which demonstrated that this route of attachment and location of uptake resulted in productive growth.     

State-level infant, neonatal, and postneonatal mortality: the contribution of selected structural socioeconomic variables

The effective field size (EFS, SAR > or = 50% of the maximum SAR at 1 cm depth) of a conventional 433 MHz water filled waveguide applicator (32 cm2, aperture area 100 cm2) has been increased by: (1) replacement of the two diverging brass side walls which are parallel to the direction of the electric field by Lucite walls; and (2) Placement of a heterogeneous permittivity in the centre of the aperture. SAR distributions were measured at several depths in layered fat-muscle phantoms. With Lucite side walls the SAR distribution becomes wider in the H-plane of the aperture, resulting in a circular SAR distribution. In this situation the EFS is 67 cm2. Additional insertion of a PVC cone with a top angle of 15 degrees at the centre of the aperture increases the EFS to 91 +/- 6 cm2 for a waterbolus of 18 x 18 x 1 cm3. The experiments also demonstrated that the resulting EFS is affected by the waterbolus size and shape. Calorimetric measurements showed that the efficiency of the improved applicator is comparable to the efficiency of the conventional water filled waveguide applicator, 50 and 56% respectively. The modifications reported provide a simple and inexpensive means to increase the EFS and can be easily implemented in water filled waveguide applicators.     

Mid-trimester emergent cerclage: a ten year single institution review

Chronic lung disease (CLD) of prematurity may be caused by a number of insults during mechanical ventilation, including barotrauma and hyperoxia. To evaluate bronchial hyperresponsiveness (BHR) in infants with CLD of prematurity, we measured changes in transcutaneous oxygen tensions (tcPO2) during methacholine inhalation challenge. Twelve infants with CLD and 22 age-matched children without respiratory diseases were enrolled in this study (ages--5 to 36 months; mean age--16.2 months). Serial doses of methacholine were doubled until a 10% decrease in tcPO2 from baseline was reached. The cumulative dose of methacholine inhaled by the time tcPO2 had been reached (Dmin-PO2) was considered to represent the dose at which reactivity to methacholine (RO2meth) had occurred. In the CLD group, Dmin-PO2 (3.50 +/- 0.1 log x milli-units) was significantly lower than in the preterm control infant group (4.31 +/- 0.2 log x milli-units) and the term infant group (4.21 +/- 0.1 log x milli-units) (P = 0.004, P < 0.001). Dmin-PO2 in the preterm control infant group was not significantly different than in the term infant group (P > 0.5). These results suggest that infants who require additional therapeutic oxygen and mechanical ventilation during the early months of life are at risk of developing early-onset, long-lasting respiratory disease that is related to an acquired BHR.     

Preventable trauma deaths in Singapore

The international normalized ratio (INR) is the current standard for monitoring anticoagulation therapy. Although simple to determine, it normally requires venipuncture and extensive laboratory resources for specimen handling and analysis. The portable capillary whole blood coagulation monitor is an alternative to laboratory venipuncture. Its promoted advantages are: it obtains a blood sample by finger-stick versus venipuncture; rapid turnaround time for results; resultant dosage adjustments (as appropriate) performed in minutes versus hours or days after testing; relative ease of use by nonlaboratory personnel; and potential for home monitoring. This project compared the results of INRs obtained through the venipuncture/laboratory process to INRs obtained by the portable monitoring process at the National Naval Medical Center. A correlation coefficient of 0.97 was determined. The difference in the mean INR results of the two testing methods was not clinically significant (p = 0.269). The portable monitor was determined to be a viable alternative to laboratory testing.     

Primary biliary stones: diagnosis and management

To review the results of treatment of primary biliary stones, 96 consecutive patients managed from 1991 to 1996 were studied retrospectively. Acute cholangitis and abdominal pain were the presenting symptoms in 57 patients (59%) and 29 patients (30%), respectively. Fifty-four patients (56%) had a history of biliary surgery. Endoscopic retrograde cholangiopancreatography, ultrasonography, and computed tomography were frequently employed for diagnosis of primary biliary stones and were performed on 84 patients (88%), 90 patients (94%), and 89 patients (93%), respectively. Intrahepatic stones were identified in 91 patients (95%) and biliary strictures in 34 patients (35%). Concomitant cholangiocarcinoma occurred in 15 patients (16%). Hepatic resection was required in 55 patients (57%) for removal of an atrophic liver lobe or a segment related to repeated infection, biliary strictures, liver abscesses, or cholangiocarcinoma. Intraoperative choledochoscopy was routinely performed in all patients to detect, remove, or confirm clearance of biliary stones. A hepaticocutaneous jejunostomy (HCJ) was constructed in 70 patients (73%) to facilitate postoperative choledochoscopic examination or biliary stone extraction. Twenty-two patients (23%) had residual stones and required postoperative choledochoscopic extraction. Complete eradication of residual stones was achieved in all patients. Postoperative morbidity occurred in 28 patients (29%), and there was one hospital death (a patient with cholangiocarcinoma). With a median follow-up of 26 months (range 2-62 months), stones recurred in three patients. In conclusion, the early results of treatment of primary biliary stones were satisfactory owing to a systematic, aggressive approach that consisted of hepatic resection, frequent construction of an HCJ, and postoperative choledochoscopy.     

Assessing the limping child with skeletal scintigraphy

Skeletal scintigraphy is frequently used in the clinical investigation of young children who present with limping as their only or predominant symptom. This article reviews techniques used for pediatric skeletal scintigraphy, skeletal tracer distribution in the immature skeleton and scintigraphic manifestations of relatively common conditions that can produce limping in children 1-6 yr old. Acute osteomyelitis, vertebral infections, transient synovitis, septic arthritis, Legg-Calvé-Perthes disease, lower extremity injuries in toddlers and osteoid osteoma are emphasized.     

Transcriptional activation of NF-kappa B activity by Epstein-Barr virus (EBV) LMP1 as a selective therapeutic strategy for EBV-associated diseases

Epstein-Barr virus (EBV) has been known to be associated with many malignant tumors, including nasopharyngeal carcinoma (NPC). Previous studies have indicated that an EBV-encoded oncoprotein, latent membrane protein 1 (LMP1), is expressed in many NPC tissues. LMP1 has been shown to stimulate HIV LTR through the two NF-kappa B binding sites within this promoter. In this study, we examined the feasibility of using this property of LMP1 as a therapeutic strategy for the treatment of NPC. This therapy consists of the preferential killing of the LMP1-expressing cells by gene transfer using the NF-kappa B-mediated herpes simplex virus thymidine kinase (HSVtk)/ganciclovir (GCV) system. The 800-bp HIV-LTR, which contains two NF-kappa B binding sites, was used to drive the HSVtk gene. Stable C33A cell clones expressing the LMP1 and the HSVtk genes were subjected to the GCV sensitivity test. Results showed that cells expressing both the LMP1 and the HSVtk genes were highly sensitive to GCV treatment. These cells were introduced into nude mice subcutaneously and tumors became palpable within 2 weeks. GCV was then introduced intraperitoneally to these mice and the sizes of the tumors were measured daily. Results showed that the tumors regressed in the group of mice carrying cells that stably expressed both the LMP1 and the HSVtk genes, but not in mice carrying cells containing LMP1 or HSVtk alone. Our data indicate that the HSVtk gene expressed from a NF-kappa B-binding motif-containing promoter that is regulated by LMP1 may be used as an in vivo gene therapy strategy of EBV LMP1-expressing cancers such as NPC.