Search

Atomic force microscopy (AFM) offers new insights into the ability of proteins to resist mechanical force. The technique has been opened up by the availability of easy-to-use instruments that are commercially available, so that the technique no longer relies on the need to build instruments in the lab. Indeed it may become common for AFM instruments to sit beside stopped-flow apparatus in protein folding laboratories. In this chapter, we describe the instrument set-up, the preparation of suitable protein substrate, and the collection of data. Data selection and analysis are more complex than for conventional stopped-flow ensemble studies, but offer new insights into the function of proteins in vivo.

Background: A considerable proportion of oral cancer and precancer is not clinically apparent and could contribute significantly to the late diagnosis and high mortality of oral cancer. A simple method to identify such occult change is needed., Methods: Patients in the Oral Dysplasia Clinics at British Columbia are currently being examined with a simple hand-held device that permits the direct visualization of alterations to autofluorescence in the oral cavity. Tissue showing loss of autofluorescence is biopsied., Results: We present 3 representative cases in which occult lesions were identified with fluorescence visualization during longitudinal follow-up, resulting in the diagnosis of a primary dysplasia in case 1, a second primary cancer in case 2, and cancer recurrence in case 3., Conclusions: This is the first report of the diagnosis of occult oral disease using a simple noninvasive device. These early examples indicate the potential value of this technology to guide the management of patients with oral lesions, facilitating the detection of high-risk changes not apparent with white-light visualization.

Intrauterine insemination (IUI) remains a therapeutic option within means of the majority of infertile couples in Malaysia. Therefore additional information on predictors of IUI success in the local context would provide a more concrete basis for counseling patients on expectations and treatment options. A retrospective analysis of 297 couples who underwent 445 IUI cycles from Jan 2005-Mar 2006 was undertaken. Four fifths were Malay with a mean paternal and maternal age of 35.53 +/- 5.82 (range 24-59) and 33.02 +/- 4.69 (range 21-46) years respectively. Causes of infertility were idiopathic (50%), endometriosis (17%) and anovulation/polycystic ovarian syndrome (15%). Almost 10% were oligoastenoteratozoospermic with another 23% oligozoospermic or astenozoospermic. Combined male and female factors occurred in 26%. A pregnancy rate (PR) of 9.4% per cycle; 14.1% per couple with a cumulative PR of 36.7% per 4 cycles was achieved. Those who became pregnant were significantly younger (31.29 +/- 4.43 vs. 33.21 +/- 4.68 years, p = 0.011) and had more follicles (13.95 +/- 9.72 vs. 11.43 +/- 6.67, p = 0.029) at the time of insemination. PR depreciated with maternal age and semen quality. Maternal and paternal age was inversely correlated to the number of follicles recruited (r = -0.30, p < 0.0005) and progressive sperm motility (r = -0.125, p = 0.013) respectively.

The empty follicle syndrome (EFS) is a rare complication of in vitro fertilization (IVF) treatment, leading to cycle cancellation. Low human chorionic gonadotropin (hCG) bioavailability and ovarian dysfunction have been implicated with this condition. This case report illustrates a typical case of EFS and several strategies suggested to overcome this problem.

By using the natural birefringence of an a-cut Nd:GdVO(4) crystal, we experimentally investigate laser operation under different light polarizations (pi- and sigma-polarized emissions) and compare their performance. The laser performance is further compared with a diode-pumped c-cut Nd:GdVO(4) laser of the same parameters. We show experimentally that the c-cut Nd:GdVO(4) laser could have good passively Q-switched performance in a low-pump-power region but is influenced by other intrinsic laser effects, such as the thermally induced cavity losses; its performance is severely degraded under high pump power. The best passively Q-switched performance obtained in our experiments is from the a-cut pi-polarized laser, which gives the narrowest pulse of 5.4 ns with the highest peak power of 20 kW. Our experimental results show that, to achieve the best performance of the passively Q-switched laser operation, an overall consideration of laser parameters is important.

Epidemiologic evidence indicates that maternal smoking increases the risk of preterm birth. While a number of plausible mechanisms for early delivery have been offered, the role of gestational hormones in this smoke-induced outcome is uncertain. Thus, a toxicologic study was performed to examine the effects and underlying hormonal mechanisms of mainstream cigarette smoke (MCS) exposure on gestational duration. Pregnant B6C3F1 mice were exposed by inhalation to MCS for 5 days/week (4 hrs/day) from Gestational Day (GD) 4 to parturition. Smoke-induced effects on gestational length, interpubic ligament length, maternal hormone secretion patterns (estradiol-17beta, progesterone, prolactin, and relaxin), body weight gain, postimplantation loss, litter size, and offspring sex ratio were examined. Dams exposed to MCS at a concentration equivalent to smoking less than one pack of cigarettes/day (carbon monoxide = 25 parts per million, total suspended particulates = 16 mg/m3) demonstrated a significant (P < 0.05) shortening of gestational duration (compared with pregnant, air-exposed mice). In addition, MCS-exposed mice sacrificed on GD 18 had significantly (P < 0.05) increased interpubic ligament length, elevated serum estrogen levels, and a reduced progesterone to estradiol-17beta ratio (compared with air-exposed controls); levels of progesterone and prolactin were only modestly decreased and increased, respectively, in the MCS-exposed mice. Smoke exposure had no significant effects on maternal relaxin levels, body weight gain, postimplantation loss, litter size, or sex ratio. Results of this study demonstrate that inhalation exposure of pregnant mice to a low dose of MCS shortens gestation and alters hormone secretory patterns, which are important for maintaining pregnancy and inducing parturition. These findings support the view that pregnant women who smoke (even modestly) may be at increased risk for preterm birth, and that early delivery may be related (at least partly) to MCS-induced.

NK cells and alphabeta- and gammadelta-CTL play important roles in cellular immunity against tumors. We previously demonstrated that NPC patients have a quantitative and qualitative deficit in gammadelta-CTL and EBV-specific alphabeta-CTL when compared to normal subjects and NPC long-term survivors. In this study we report further observations of a complementary activation of peripheral NK cells in NPC patients. The NK cells in these patients, compared to those of healthy subjects and NPC survivors, were preferentially activated in response to the stimulation of myeloma cell line XG-7 and expanded in the presence of exogenous IL-2. The production of IFN-gamma was lowest in the patient group, whereas IL-12, IL-15 and TNF-alpha were produced in higher levels in patients than in the donors and survivors. The cytolytic effect of the NK cells against NPC cells in the patient group was also higher than that of the donors and survivors. Furthermore, the patients at later stages of NPC had lower gammadelta-CTL activity but higher NK cytotoxicity towards NPC targets, with higher production of IL-12, IL-15 and TNF-alpha but lower production of IFN-gamma than in patients at earlier stages. This might be part of a triggered compensatory re-activation of the innate immunity, believed to be mediated through various cytokines and chemokines when adaptive T cell immunity is breached. Together, these data suggest complementary roles of innate and adaptive immune response in tumor immunity where NK cells, gammadelta- and alphabeta-CTL compensate for the deficits of one another at different stages of tumor invasion.

A 20 year-old woman presented with features of a twisted ovarian cyst and had an emergency laparotomy Intraoperative findings revealed bilateral, solid ovarian tumors and a left oophorectomy with biopsy of the contralateral ovary performed. Histopathology report confirmed Burkitt lymphoma of ovary. There was no other evidence of lymphoma elsewhere. The primary Burkitt lymphoma of the ovaries was successfully managed with six courses of highly toxic chemotherapy (Berlin-Frankfurt- Munster 1986 protocol). The patient has remained disease free for the last 36 months.

Early pregnancy is a powerful negative risk factor for breast cancer (BCa) in women. Pregnancy also protects rats against induction of BCa by carcinogens such as N-methyl-N-nitrosourea (MNU), making the parous rat a useful model for studying this phenomenon. Smoking during early pregnancy may lead to an increased risk of BCa in later life, possibly attributable to carcinogens in cigarette smoke (CS), or to reversal of the parity-related protection against BCa. To investigate these possibilities, 50-day-old timed first-pregnancy rats were exposed to standardized mainstream CS (particle concentration = 50 mg/m3) or to filtered air (FA) 4 h/day, Day 2-20 of gestation. Age-matched virgin rats were similarly exposed to CS or FA. At age 100 days, the CS or FA-exposed, parous and virgin rats were injected s.c. with MNU (50 mg/kg body wt), or with MNU vehicle. Mammary tumors (MTs) first appeared in virgin rats 9 weeks post-MNU injection. While no MTs were detected in FA-exposed parous rats until 18 weeks post-MNU, MTs appeared in the CS-exposed parous rats as early as 10 wks (P < 0.02). As no MTs developed in CS-exposed rats not injected with MNU, CS did not act as a direct mammary carcinogen. Serum prolactin concentration on Day 19 of pregnancy in CS-exposed dams was reduced by 50% compared with FA-exposed dams (P < 0.005). CS exposure during a pregnancy may thus 'deprotect' rats, enhancing their vulnerability to MNU-induced BCa. Prenatal CS exposure had no detectable effect on the immune responses of the pups examined at 3, 8 or 19 weeks of age. However, prolactin concentration in stomach contents (milk) of 3-day-old pups suckled by CS-exposed dams was decreased when compared with that of FA-exposed dams (P < 0.032). As milk-borne prolactin modulates development of the central nervous and immune systems of neonatal rats, CS exposure of the dams could adversely affect later maturation of these systems by reducing milk prolactin.

Recurrent spontaneous abortion, defined as three consecutive abortions, occurs in approximately 1% to 2% of couples. Although the cause is unknown in up to 50% of cases, about 5% of these couples are found to be a balanced translocation carrier. We report a case in which the mother was identified to be a translocation carrier following the birth of a baby with multiple congenital abnormalities.

Nasopharyngeal carcinoma (NPC) is a common cancer among Chinese, especially Southern Chinese; except for a few other ethnic groups with moderate incidence, it is otherwise a rare cancer in the world. NPC has a male dominance of about 3:1 and mainly afflicts people in mid-life. There is now compelling evidences to suggest that Epstein-Barr virus (EBV), a category I human tumor virus defined by UICC (International Agency for Research on Cancer) in 1997, is a causal agent of NPC and is most likely to be involved in the multi-step and multi-factorial development of NPC. In this article, the role of EBV in pathogenesis of NPC is reviewed briefly, and principle applications of EBV antibodies and EBV DNA as markers of NPC are outlined. Based on current knowledge of EBV antibody responses by NPC and taking available testing technologies into account, serologic screening strategy to facilitate efficient early detection of NPC is formulated.

Epidemiologic evidence suggests that prenatal exposure to intact (unfractionated) cigarette smoke (CS) increases the incidence of cancer in the offspring. A toxicology study was carried out to examine the effects and underlying mechanisms of prenatal exposure to mainstream cigarette smoke (MCS) on offspring resistance to tumor challenge and surveillance mechanisms critical for the recognition and destruction of tumors. Pregnant B6C3F1 mice were exposed by inhalation to MCS for 5 days/week (4 h/day from gestational day 4 to parturition). Smoke-induced effects on offspring-host resistance to transplanted tumor cells; natural killer (NK) cell and cytotoxic T-lymphocyte (CTL) activity; cytokine levels; lymphoid organ immune cell subpopulations; and histology-were examined in 5-, 10- and 20-week-old male and female offspring. At a concentration of smoke roughly equivalent to smoking <1 pack of cigarettes/day, prenatally exposed male offspring challenged at 5 week of age with EL4 lymphoma cells demonstrated a greater than two-fold increase in tumor incidence (relative to age-/gender-matched air-exposed offspring); tumors in prenatally smoke-exposed pups also grew significantly faster. Cytotoxic T-lymphocyte activity in the smoke-exposed 5- and 10-week-old male pups was significantly less than that of the age- and gender-matched controls. No effects of prenatal CS exposure were observed on offspring NK activity, cytokine levels, lymphoid organ histology, or immune cell subpopulations. Results demonstrated that exposure of pregnant mice to a relevant dose of MCS decreased offspring resistance against transplanted tumor cells and persistently reduced CTL activity in prenatally exposed pups. This study provides biological plausibility for the epidemiologic data indicating that children of mothers who smoke during pregnancy have a greater risk of developing cancer in later life.

Aim:   Ovarian hyperstimulation syndrome (OHSS) is a potentially life-threatening, iatrogenic complication of assisted reproduction and has been associated with poor in vitro fertilization outcome. The aim of the present study was to evaluate the pregnancy rate and outcome following severe OHSS, at a single center over a three-year period. Methods:   The incidence of severe OHSS at the IVF Center, National University of Singapore, in Singapore, was 4% (48 cases over 1200 cycles) during the period of 1997-2000. The present retrospective study compared 48 cases of severe OHSS to 144 age-matched, contemporaneous controls without OHSS. Results:   The total gonadotropin required for severe OHSS group was found to be lower than for that of controls (2664.06 ± 768.29 IU vs 3349.58 ± 2003.73 IU), although duration of stimulation was similar. The OHSS group was associated with a fivefold increase (OR 5.293, 95% CI: 2.116-13.238) in pregnancy rate compared to controls (87.5% vs 56.9%; P  < 0.05). Late OHSS was more common (38/48 cases) and had a pregnancy rate of 97% per embryo transfer. There was no significant difference in the multiple pregnancy (54% vs 48%; P  > 0.05) and miscarriage rates (14% vs 7.3%; P  > 0.05) between the groups. Conclusion:   Severe OHSS at our center were mostly late onset. The pregnancy rate was significantly higher, but multiple pregnancy and miscarriage rates were not significantly increased when compared to the age-matched contemporaneous controls. (Reprod Med Biol 2005; 4 : 207-211).

Protein engineering Phi-value analysis combined with single molecule atomic force microscopy (AFM) was used to probe the molecular basis for the mechanical stability of TNfn3, the third fibronectin type III domain from human tenascin. This approach has been adopted previously to solve the forced unfolding pathway of a titin immunoglobulin domain, TI I27. TNfn3 and TI I27 are members of different protein superfamilies and have no sequence identity but they have the same beta-sandwich structure consisting of two antiparallel beta-sheets. TNfn3, however, unfolds at significantly lower forces than TI I27. We compare the response of these proteins to mechanical force. Mutational analysis shows that, as is the case with TI I27, TNfn3 unfolds via a force-stabilised intermediate. The key event in forced unfolding in TI I27 is largely the breaking of hydrogen bonds and hydrophobic interactions between the A' and G-strands. The mechanical Phi-value analysis and molecular dynamics simulations reported here reveal that significantly more of the TNfn3 molecule contributes to its resistance to force. Both AFM experimental data and molecular dynamics simulations suggest that the rate-limiting step of TNfn3 forced unfolding reflects a transition from the extended early intermediate to an aligned intermediate state. As well as losses of interactions of the A and G-strands and associated loops there are rearrangements throughout the core. As was the case for TI I27, the forced unfolding pathway of TNfn3 is different from that observed in denaturant studies in the absence of force.

Purpose: Four flavones, namely Apigenin, Baicalein, Chrysin and Luteolin, were selected for study and comparison of their absorption and metabolism in gut using the in vitro Caco-2 monolayer model., Methods: Transport of the four flavones in the Caco-2 monolayer model was studied in both Apical-to-Basolateral and Basolateral-to-Apical directions., Results: All of the selected flavones were able to pass through the Caco-2 cell monolayer with no significant efflux. The permeability coefficients of the four compounds were all greater than 10(-6) cm/sec and those of Apigenin and Baicalein were even greater than 10(-5) cm/sec. Glucuronides of the tested flavones were all formed in the Caco-2 cell monolayer model and a structure-activity relationship has been proposed for this glucuronidation. In addition, Apical-to-Basolateral transport studies were performed in Caco-2 models pre-treated with Chrysin, an UGT inducer. Quantities of the corresponding glucuronides formed were all significantly higher in Chrysin-treated groups than the controls., Conclusions: It demonstrated that all selected flavones were substrates of the UGT isoforms that are inducible by Chrysin.

Microinvasive squamous cell carcinoma of the uterine cervix is a recognized entity and is defined as carcinoma with invasion of less than 5 mm penetration of the stroma and seldom metastasized. Our patient was a 70-year-old, multiparous woman who had a microinvasive, cervical, squamous cell carcinoma. The tumor had spread superficially into the entire endometrial cavity up to the fundus, totally replacing the columnar epithelium. This is an extremely rare phenomenon, with fewer than 20 cases reported so far in the literature.

We reviewed the unenhanced computer tomography (CT) scans of 53 patients with surgically proven acute cholecystitis, where 27 patients presented with hyperdense gallbladder wall. To our knowledge, this sign was never reported before. Because mucosa is highly sensitive to ischemia, early mucosal necrosis and hemorrhage may result in CT-detectable high density. Similar episode may also occur in acute cholecystitis. This sign also reflects high probability for acute gangrenous cholecystitis. We suggest that patients with this sign should have urgent treatment.

Imperforate hymen is an uncommon obstructive anomaly of the female reproductive tract, which usually presents with intermittent and cyclical abdominal pain. Although it is usually sporadic, four cases of familial occurrence of imperforate hymen have been reported so far. Imperforate hymen is seldom associated with complications if it is detected early. In view of the possible familial occurrence, it is important to have a high index of suspicion in women who present with imperforate hymen. A detailed menstrual history of other female family members is necessary to enable early detection.

A first toxicity identification evaluation (TIE) was conducted in three phases using the Microtox test to identify the major toxicant(s) in effluent discharged from a dyeing plant in Hong Kong. In Phase I toxicity characterization indicated that anions were likely to be the major toxicants for the entire effluent. In Phase II concentrations of sulfite and other anions in the original and the anion exchange resin-treated effluent samples were determined by ion chromatography. Anions, which were found in the effluent at comparatively high concentrations and were suspected of being responsible for the toxicity to luminescent bacteria, were selected for further study in Phase III. Investigation in Phase III using the spiking and mass balance approaches confirmed that the sulfite ion was the major toxicant in the effluent., (Copyright 2003 Wiley Periodicals, Inc.)

The pathogenesis of neonatal necrotizing enterocolitis (NEC) is unknown. Intestinal dilatation and preferred occurrence of NEC at sites of bacterial overgrowth (colon and ileum) are common findings. The study attempted to produce NEC with increasing intraluminal pressures and bacterial concentrations in two different aged groups of rats. First, 10-cm terminal ileum segments were isolated with intact vascular pedicles in 1-and 3-month-old rats, and a dose of 10(11) E. coli in 1 ml was injected into each segment. Intraluminal pressure was sustained for 1 h at 150, 100, 50 and 0 cmH(2)0, respectively, in four experimental groups ( n=6). The isolated loop was then returned to the abdominal cavity and assessed grossly for NEC after 24 h. Histological examination was performed by a pathologist (KWC) who was blinded to the procedures. Second, the procedure was repeated with doses of 10(8), 10(5) and 0 bacteria/ml ( n=6) at intraluminal pressure of 100 cmH(2)0 in 1-month-old rats. Third, in another experimental group, oxygenation of the pedicled loop was assessed by oximetry as the intraluminal pressure increased and the findings were correlated with aortic blood pressure. The blood pressures (mean+/-SD) for 3- and 1-month-old rats were 110+/-6 and 72+/-4 mmHg, respectively. Hypoxia (<50% oxygen saturation) of the bowel was detected when the intraluminal pressure exceeded the mean blood pressure. The relative incidences of NEC in the bowel with intraluminal pressure above and below mean blood pressure were 100% (6/6) vs. 4% (1/24; P<0.05) in 3-month-old rats, and 100% (12/12) vs. 11% (2/18; P<0.05) in 1-month-old rats. There was no occurrence of NEC in bowel injected with 10(5) E. coli/ml and less at 100 cm intraluminal pressure. Increased intraluminal pressure results in bowel hypoxia and in the presence of adequate bacterial concentration predisposes to the development of NEC. Young age is associated with a lower threshold for increased intraluminal pressure leading to NEC.

Background & Objective: The aim of this study was to optimize a dual-antibody assay for sero-diagnosis of nasopharyngeal carcinoma(NPC) by evaluating 4 Epstein-Barr virus(EBV) antigen-based enzyme-linked immunosorbent assays(ELISAs)., Methods: The serum samples of 57 pretreated NPC patients and 58 apparently healthy adults in Guangzhou were collected. The levels of anti-EBV antibody in the sera were tested by 4 ELISAs, which were developed using fusion proteins of glutathione transferase and EBV specific recombinant antigens, namely, EBNA1-IgA, EBNA1-IgG, Zta-IgA, and Zta-IgG., Results: When evaluated individually, the sensitivity(0.9123) and negative predictive value(0.9074) of EBNA1-IgA were the highest among the 4 ELISAs tested. Zta-IgA test had the highest individual accuracy rate(pi, 0.8870) and Youden index(J, 0.7738). The dual positives for EBNA1-IgA and Zta-IgA were the highest among the 4 dual positives when paired ELISAs were evaluated. Five NPC patients with negative reaction to EBNA1-IgA showed positive reaction of Zta-IgA, and 7 NPC patients with negative reaction to Zta-IgA showed positive reaction of EBNA1-IgA., Conclusion: The EBNA1-IgA assay is more suitable than the other 3 ELISAs(EBNA1-IgG, Zta-IgA, and Zta-IgG) when used individually for serological diagnosis of NPC. When two assays are combined, EBNA1-IgA and Zta-IgA have complementary effect on serological diagnosis for NPC and is thus an optimal combination of serum antibody assays.

We report the experimental observation and numerical simulation of deterministic chaos in a diode-pumped Nd:YAG solid-state laser that is passively Q switched by a Cr4+:YAG crystal saturable absorber. We show that apart from the stable Q-switched operation the laser can also exhibit complicated nonlinear dynamics, including the period-doubling route to chaos and periodic windows.

The efficacy of immunization with Salmonella typhimurium aroA to deliver the plasmid pRc/CMV-HBsAg (i.e. an oral DNA vaccine) was compared with that of intramuscular immunization with the same plasmid DNA, and with recombinant HBsAg protein, in a HBsAg transgenic mouse model. A single dose of oral DNA vaccine evoked vigorous Th1 cell and CTL responses and production of IgG2 subclass of anti-HBs after 2 weeks, and this was accompanied by a transient hepatitic flare with elevated alanine aminotransferase in the first 3 weeks. Concomitantly, the level of HBsAg-mRNA in liver tissues decreased by more than fourfold and viral-antigen expression was curtailed markedly in hepatocytes compared with controls. Hepatitic flare subsided after 3 weeks, but suppression of the transgene expression was continued in the absence of overt liver pathology for the remaining duration of the experiment (i.e. 12 weeks), and possibly beyond. The other vaccines could also break immune tolerance, but this was achieved only after repeated booster doses of the respective vaccines, and they did not affect transgene expression, or induce hepatic flare. We previously showed in non-transgenic mice that immunization by the oral DNA vaccine is achieved by an active intestinal infection with a bacterial carrier that is an adept intracellular parasite, and the immune response to the vaccination is orchestrated by phagocytic APC. Our present findings further implicated that the combined effects of an innate and a specific immune response induced by oral DNA vaccination are crucial in down-regulating HBsAg-transgene expression in hepatocytes.

Immunosensors based on the microgravimetric quartz crystal microbalance (QCM) technique have been developed for the detection of Salmonella species from serogroups A, B and D. Salmonella serogroup-specific murine monoclonal antibodies, respectively, raised against these serogroups were immobilized onto the silver electrodes of piezoelectric (PZ) crystals by cross-linkage via glutaraldehyde (GA) to the electrode surfaces pre-coated with thin polyethyleneimine (PEI) layer. The specific immunosensors developed gave responses in linear ranges from 10(5) to 5x10(8) cells per ml with no significant interference from other strains of Salmonella and Escherichia coli up to 10(8) cells per ml. They showed good repeatability and excellent linear range, achieving detection limits down to 10(4) cells per ml with ability to distinguish different strains of Salmonella. These biosensors exhibited an exquisite specificity evidenced by their ability to discriminate antigens, the structures of which differ only by the isomeric form of di-deoxyhexose. The antibody-modified crystals showed no loss in activity over 4 days under storage at 4 degrees C.

Previous studies identified CD56(+) and CD56(-) subsets of peripheral gamma delta T cells from healthy donors. Both subsets responded to stimulation by a myeloma cell line, XG-7 and undergo vigorous ex vivo expansion in the presence of exogenous IL-2. They are cytotoxic for different tumor targets including nasopharyngeal carcinoma, but they differ from one another in that the CD56(-) subset has an additional growth requirement for IL-7 and exhibited greater cytotoxicity against nasopharyngeal carcinoma (NPC) targets. These immune cells were further shown to retard tumor growth in a nude mice NPC model. To assess if these immune cells might contribute to host defense against NPC, we compared gamma delta T-cell status of NPC patients with healthy donors and survivors who had been in clinical remission of the cancer. It was found that peripheral gamma delta T cells of patients were impaired in their response to the stimulatory effects of XG-7 and exhibited weak or essentially no cytotoxicity for the NPC targets. The deficits were present in early and advanced stages of the cancer but were restored among survivors after successful treatment of the cancer. These findings support a role for peripheral gamma delta T cells in host defense against NPC. It was noted that these immune cells comprise less than 5% of peripheral blood monocytic cells and hence it was not surprising that this component of host defense was breached early in the development of the cancer., (Copyright 2002 Wiley-Liss, Inc.)

We have evaluated the performance of 3 new EBV ELISA for the diagnosis of nasopharyngeal carcinoma (NPC). The tests were specific for EBNA 1 IgA, EBNA 1 IgG and zta IgG, respectively. Their distinct antigenic specificity permits these assays to be used in concert in an approach that differentiates patients and apparently healthy subjects on the basis of their antibody spectrum. By so exploiting a distinguishing feature of NPC first described by Lloyd Olds and his group (Olds et al., Proc Nat Acad Sci 1966;56:1699-1704) [corrected] that the patients sustain high levels of a broad spectrum of serum EBV antibodies, this approach achieved a sensitivity of 92% and a specificity of 93%, surpassing the performance of each of these assays individually. The enhanced performance is especially useful in population screening. It was shown that relative risk of NPC sustained by apparently healthy subjects residing in a high incidence area for NPC in the Pearl River estuary in Southern China may vary according to EBV antibody spectrum. The risk of the cancer was markedly reduced with odds ratios of 0.009 for 59% of those who had low level of all 3 antibodies. The risk was increased as antibody spectrum broadens and the risk was the highest with an odds ratio of 138 for 0.4% of those who had high levels of all 3 antibodies. Thus, EBV antibody spectrum may serve to guide follow-up measures for early detection of the cancer and/or risk counseling according to level of the risk of the cancer sustained by the screened individuals., (Copyright 2001 Wiley-Liss, Inc.)

Serum samples were taken from 57 patients with sporadic non-A, -B, and -C (Non A, B, C) acute hepatitis at different times after onset of the disease and tested for the presence of the hepatitis E virus (HEV) RNA, IgM, and low avidity IgG antibodies. The viral antibodies were detected using two ELISA. One assay (GL) was produced using a mixture of recombinant peptides specified by ORF2 and ORF3 of the viral genome. The other was produced with an ORF2 specified peptide, pE2. The latter occurs naturally as homodimer, it is recognized strongly in its dimeric form by human sera and, in the primate model, it confers protection against experimental HEV infection. Nineteen samples were positive for one or more of these acute markers of HEV infection, 14 of which were acute sera with elevated ALT levels and 5 were convalescent sera with normal ALT level. The results showed that icteric phase of sporadic hepatitis lasts for about 17 days and it coincides with a period when viremia is subsiding as HEV antibodies are developing. Viremia was intermittent and all but one of the 5 instances were confined to the icteric phase with elevated ALT levels. On two of these occasions, viremia preceded detection of HEV antibody, on another 2 occasions it was concurrent with the detection of pE2 specific IgM and/or low avidity IgG and only in one case of protracted viremia was the viral genome detected concurrently with avid pE2 IgG antibody. Ten (71%) of the 14 acute sera were reactive for pE2 IgM, eight (57%) were reactive for low avidity pE2 IgG, and six (43%) for the GL IgM. The sensitivity for the diagnosis of acute hepatitis E may be increased to 87% by combining pE2 IgM and viremia. GL IgM was detected later, but persisted for a longer period of time than the pE2 antibodies, and it was the only acute antibody detected in the convalescent sera., (Copyright 2002 Wiley-Liss, Inc.)

A monoclonal antibody (MAb), MO15, was raised against the lipopolysaccharide antigen of an epsilon15-lysogenized serogroup E(1) Salmonella strain. The O factor 15-specific MAb MO15, together with another serogroup E-specific MAb, can differentiate among phage lysogenization variants in serogroup E salmonellae. Their epitope specificities in relation to conventional O-antigenic structures are discussed.

To design efficient culture strategies for use with immunoassays to detect Salmonella in food, the growth of these organisms was investigated according to the Bacteriological Analytical Manual (BAM) and enrichment-immunoassay (EI) culture procedures. The cultures were further evaluated using a commercial enzyme-linked immunosorbent assay (ELISA) kit. The BAM procedure includes pre-enrichment in nutrient broth (NB) for 16 h followed by selective enrichment in either Rappaport-Vassiliadis (RV) or tetrathionate brilliant green (TBG) broth for 16 h. The EI procedure includes pre-enrichment in NB for 4 h, selective enrichment in RV for 16 h and post-enrichment in NB for 4 h. The effects of different incubation times for pre- and post-enrichment, and different culture media for selective enrichment (TBG and RV) and post-enrichment in NB and Brain Heart Infusion broth (BHI) on the growth of the bacteria and ELISA titers in the EI procedure were also investigated. Salmonella enteritidis and S. typhimurium inoculated at different initial concentrations between 0.1 and 35 CFU/ml grew to similar concentrations of 10(7) to 10(8) colony forming unit (CFU)/ml in pure culture and generally 2 to 4 fold lower concentrations (P<0.05) in mixed culture using spiked chicken rinse. In the BAM procedure, the concentration of Salmonella cultured in RV was higher (P<0.01) than that in TBG. The cultures in TBG showed positive results for ELISA, but those in RV were generally negative. In the EI procedure, the ELISA titers from cultures post-enriched in NB or BHI were higher (P<0.01) when TBG, as compared to RV, was used for selective enrichment. Post-enrichment in BHI yielded higher numbers of Salmonella and higher ELISA titers than those in NB (P<0.05) for post-enrichment. This study demonstrated that in both culture procedures small numbers of Salmonella could be increased to at least 10(7) CFU/ml which is detectable by most ELISAs, and that the type of the culture media used may have a significant impact on ELISA results.

The objectives of this study were to determine the total plasma and lipoprotein lipid concentration and composition and cholesteryl ester transfer activity in two diabetic animal models (alloxan-induced diabetes in rabbits and streptozotocin-induced diabetes in rats). Furthermore, we wanted to determine if the severity of diabetes influences lipoprotein lipid profiles and cholesteryl ester transfer activity. Rats and rabbits were randomly divided into non-diabetic and diabetic groups. Rats were administered either 55 mg/kg or 100 mg/kg of streptozotocin intravenously through the tail vein, while rabbits were administered 100 mg/kg or 200 mg/kg of alloxan intravenously through the marginal ear vein under light anesthesia. Hyperglycaemia was tested for at 48 hr following the doses. Total and lipoprotein cholesterol and triglyceride concentrations using enzymatic kits and cholesteryl ester transfer activity from low-density lipoproteins to high-density lipoproteins using 3H-cholesteryl ester incorporated into low-density lipoproteins were determined. Elevations in both total and lipoprotein cholesterol and triglyceride concentrations and alterations in lipoprotein lipid composition are observed following the onset of drug-induced diabetes in rats and rabbits compared to non-diabetics. However, these findings were observed only in animals administered the higher streptozotocin and alloxan dose. Furthermore, cholesteryl ester transfer from low-density lipoproteins to high-density lipoproteins is not significantly different in drug-induced diabetic compared to non-diabetic rats and rabbits, regardless of which streptozotocin and alloxan dose was used. These findings suggest that difference in lipoprotein lipid concentration and composition as a result of drug-induced diabetes is independent of cholesteryl ester transfer activity in both rats and rabbits. Furthermore, diabetic severity may influence lipoprotein metabolism in these animal models.

Unlabelled: New measures aimed at reducing nosocomial infection in our neonatal intensive care unit (NICU) were introduced over a 3-month period from 1 July to 30 September 1994., Objective: The aim of this study was to evaluate the impact of these measures on the incidence of nosocomial infection in our NICU., Methods: The new measures introduced were: 1. grouping of all blood investigations to allow for fewer blood samplings per baby per day; 2. reduction of routine blood investigations after the acute illness has stabilised, and 3. a system of aseptic delivery of drugs through a central venous catheter, thereby reducing the need for peripheral intravenous lines. Nosocomial infections were defined according to the criteria spelt out in the Centres for Disease Control (CDC) guidelines. Data for the study was obtained from the ongoing surveillance carried out by the hospital's infection control team. Period 1 (1 year duration) was prior to the implementation of the new measures. Period 2 (1 year duration) was after implementation of the new measures., Results: The overall nosocomial infection patient rates (expressed as number of infections per 100 intensive care unit patients) were 17.6 for Period 1 and 7.5 for Period 2. The overall nosocomial infection patient-day rates (expressed as number of infections per 1000 patient-days) were 13.5 and 6.1 respectively (p < 0.01). When the infants' birth weights were stratified as < 1500 g, 1500-2500 g, and > 2500 g, the greatest decline in both the overall nosocomial infection patient rate and nosocomial infection patient-day rate was seen in infants weighing < 1500 g. There was also a significant decline in the rates of blood-stream infections in infants weighing < 1500 g (from 7.5 to 2.8 per 1000 patient-days) (p < 0.05). Ventilator associated pneumonias also showed a decline from 3.3 to 1.0 pneumonia per 1000 ventilator days. The organisms responsible for the majority of blood stream infections in Period 1 were methicillin-resistant Staphylococci Aureus (MRSA), coagulase-negative staphylococci, gram-negative bacilli and candida. In Period 2, coagulase-negative staphylococci was the predominant organism., Conclusion: We conclude that there was a reduction in nosocomial infection rates. The new measures introduced may have contributed to this reduction.

The objective of the proposed study was to determine the distribution in plasma lipoprotein of free all-trans retinoic acid (ATRA) and liposomal ATRA (Atragen; composed of dimyristoyl phosphatidylcholine and soybean oil) following incubation in human, rat, and dog plasma. When ATRA and Atragen at concentrations of 1, 5, 10, and 25 micrograms/ml were incubated in human and rat plasma for 5, 60, and 180 min, the majority of the tretinoin was recovered in the lipoprotein-deficient plasma fraction. However, when ATRA and Afragen were incubated in dog plasma, the majority of the tretinoin (> 40%) was recovered in the high-density lipoprotein (HDL) fraction. No differences in the plasma distribution between ATRA and Atragen were found. These data suggest that a significant percentage of tretinoin associates with plasma lipoproteins (primarily the HDL fraction) upon incubation in human, dog, and rat plasma. Differences between the lipoprotein lipid and protein profiles in human plasma and in dog and rat plasma influenced the plasma distribution of ATRA and Atragen. Differences in lipoprotein distribution between ATRA and Atragen were not observed, suggesting that the drug's distribution in plasma in not influenced by its incorporation into these liposomes.

We studied 13 consecutive infants admitted to our Neonatal Intensive Care Unit over 37 months from 1 June 1994 to 30 June 1997, who were diagnosed with severe persistent pulmonary hypertension (PPHN) meeting extracorporeal membrane oxygenation (ECMO) criteria as defined by Bartlett and/or Short. They were managed with conservative ventilation strategy, with emphasis on the use of moderate ventilatory pressures whilst avoiding paralysis. Peak inspiratory pressure (PIP) on intermittent mandatory ventilation was adjusted according to adequate chest excursion. High PIP was avoided. Two main ventilatory techniques were used: 1) low ventilatory rate < or = 40/min, PIP 20 to 30 cmH2O, inspiratory time (IT) 0.5 seconds, positive end-expiratory pressure (PEEP) 5 cmH2O, and 2) high ventilatory rate 100/min, PEEP 0 cmH2O, IT 0.3 seconds. The aim was to keep preductal PaO2 > or = 50 mmHg. We did not sought to achieve alkalotic pH or low PaCO2. When PIP requirements exceeded 30 to 35 cmH2O, the use of an alternative rescue therapy such as pulmonary vasodilator, high frequency ventilation and/or surfactant were considered. Only 1 infant died of PPHN. Low mortality due to PPHN can be achieved using this strategy. There is a need for a randomised controlled trial to compare this strategy with other alternative treatment strategies.

Two hundred and thirty six women who underwent abdominal hysterectomy for benign disease at Fairfield District Hospital were studied retrospectively. Eleven patients received a total of 28 units of blood. The transfusion rate was 4.7%. The average number of units transfused per operation was 0.12. Each transfused patient received an average of 2.5 units with a range of 1-4 units. Only 27% of cross-matched blood was actually transfused. Patients with preoperative anaemia, prolonged operation time and a larger uterus were more likely to require blood transfusion. The group and screen procedure is an adequate preoperative blood order for patients having abdominal hysterectomy.

We previously described an antigen capture enzyme-linked immunosorbent assay which makes use of monoclonal antibody T6, which recognizes an epitope on the outer core polysaccharide of Salmonella lipopolysaccharide molecules that is common to almost all Salmonella serovars. In this paper, we show that this assay can detect between 10(5) and 10(7) Salmonella cells per ml even in the presence of excess Escherichia coli. A total of 153 of 154 (99%) serogroup A to E strains and 51 of 78 (71%) serogroup F to 67 strains were reactive as determined by this assay. This corresponds to a detection rate of approximately 98% of all salmonellae known to affect humans. None of the 65 strains of non-Salmonella bacteria tested positive. Taking advantage of the O-factor polysaccharides also present on the antigen captured by the immobilized T6 antibody, we showed that 136 of 154 Salmonella serogroup A to E strains (88%) were correctly differentiated according to their serogroups by use of enzyme conjugates of a panel of O-factor-specific monoclonal antibodies. We evaluated this assay for the detection and serogroup differentiation of salmonellae directly from enrichment cultures of simulated food, eggs, pork, and infant formula milk. All 26 samples which had been contaminated with Salmonella spp. were detected by T6 (100% sensitivity), with only one false-positive result from 101 samples not contaminated by Salmonella spp. (99% specificity). The detection time was substantially reduced to between 17 and 29 h, depending on the enrichment methods used. Since there were no false-negative results, we concluded that this enrichment-immunoassay method can afford rapid screening for Salmonella spp. in food samples.

3 neonates admitted into our intensive care unit had their arterial blood gases analyzed. A total of 64, 67 and 73 arterial blood samples were analyzed for the 3 neonates respectively. The relationship between PaO2 and the corresponding SaO2 were plotted in an oxygen hemoglobin dissociation curve. PaO2 of 50mmHg corresponded to SaO2 of 80%, 84% and 92% for the 3 babies respectively, reflecting the fact that SaO2 can differ considerably. PaO2 of 50mmHg or SaO2 of 87% by themselves are inadequate as indicators of lower limit of arterial oxygenation. Indeed a consideration of other factors such as oxygen consumption, cardiac output, hemoglobin concentration are integral to this issue. PaO2 of 70mmHg corresponded to SaO2 of 92%, 93% and 97% respectively. However, at the upper limit of arterial oxygenation, the oxygen hemoglobin dissociation curve flattens out and PaO2 is a more sensitive indicator of the upper limit of arterial oxygenation as compared to SaO2.

A Malay baby with multiple cranial nerve involvement consistent with the Moebius sequence (syndrome) is reported. He also had many non-Central Nervous System (CNS) related defects which include limb reduction defects and the Poland sequence. A short annotation and the spectrum of this disorder are presented. In view of many reported related disorders, Moebius sequence may occur as a part of a broader pattern of malformation.