Two contiguous outbreaks of dengue type 2 in north Queensland

OBJECTIVES

To investigate two outbreaks of dengue type 2 in north Queensland, one in the Torres Strait beginning in late 1996, the other in a Cairns suburb in early 1997.

DESIGN

Epidemiological investigation of all laboratory-confirmed cases of dengue, entomological investigation of the local environment, and laboratory analysis of the isolated dengue viruses.

MAIN OUTCOME MEASURES

Numbers of confirmed and of locally acquired cases; virus serotype; comparison of nucleotide sequences between viruses isolated from the two outbreaks; and Breteau Index (BI = number of containers with larvae of the mosquito vector Aedes aegypti found per 100 houses investigated) on the affected islands and in the Cairns suburb.

RESULTS

There were 201 confirmed cases of dengue in the Torres Strait outbreak, which lasted nearly seven months, and seven confirmed cases in the Cairns outbreak, which lasted about nearly 11 weeks. Most (190) were confirmed as dengue type 2. Nucleotide sequencing of viruses isolated from the two outbreaks showed they were identical. Ae. aegypti breeding sites were very common on the five Torres Strait islands surveyed (BIs, 73-219--high risk), but less so in the Cairns suburb (BI, 23). The most common breeding sites were water storage reservoirs, particularly rainwater tanks, on the outer Torres Strait islands, discarded containers (such as plastic containers, buckets and tyres) on Thursday Island, and garden items (such as flowerpot bases and jars) in Cairns.

CONCLUSIONS

The virus responsible for the Cairns outbreak was most probably introduced from the Torres Strait, whereas the virus responsible for the Torres Strait outbreak was imported from Papua New Guinea. Preventive strategies tailored to specific locations are needed to reduce breeding of Ae. aegypti in north Queensland, and the consequent risk of future outbreaks of dengue.

Distress and the micturating cystourethrogram: does preparation help?

This study evaluates the impact of therapeutic preparation methods on children undergoing MCUG. Parents of 35 children who had undergone MCUG were surveyed by questionnaire. The child's reaction to investigation was assessed using the Groningen Distress Rating Scale (rating 1 = calm > 5 = panic) and parental coping styles using the Utrecht Coping List. Families received one of two types of therapeutic preparation: storybooklet or storybooklet and play preparation. Reported distress levels were significantly lower with therapeutic preparation (mean score 2.5 +/- 1.02 SD) than without (mean score 3.3 +/- 1.22 SD). Previously, controls reported 46% of anxiety-linked behaviour changes post-MCUG, falling to 13% after therapeutic preparation. Parents who gave a candid explanation reported significantly lower child distress levels (mean 2.0 +/- 0.91 SD) than those parents who avoided upsetting details (mean 3.1 +/- 0.47 SD). We conclude that distress associated with the MCUG can be reduced by therapeutic preparation of the child and family prior to investigation.

A biotin-regulated locus, bioS, in a possible survival operon of Rhizobium meliloti

A novel biotin-inducible DNA locus, bioS, was found in Rhizobium meliloti 1021 by mutation with a transposable promoter probe. The promoterless nptII reporter responded to 40 nM biotin with a sixfold increase in NPTII protein. Stationary-phase mutant cells accumulated 50% more 14C-biotin than corresponding wild-type cells. The prototrophic mutant competed equally with the wild type in biotin-free medium but poorly when 40 nM biotin was present. The 588-bp bioS is located among three genes showing homology to survival operons of other bacteria, and it may be part of a system that R. meliloti uses to respond to plant biotin signals.

Ross River virus in mosquitoes (Diptera:Culicidae) during the 1994 epidemic around Brisbane, Australia

During the summer 1994 outbreak of epidemic polyarthritis in suburban Brisbane, 29,931 adult female mosquitoes were collected by octenol-CO2 light traps and tested for virus by species in pools of approximately 20 using an in situ enzyme-linked immunoassay. Overall, 63 isolations of Ross River (RR) virus were made from 7 different mosquito species, including 23 from freshwater-breeding Culex annulirostris Skuse, 13 from peridomestic Aedes notoscriptus (Skuse), 4 from Aedes procax (Skuse), 12 from the brackish water-breeding Aedes funereus (Theobald), 9 from saltmarsh Aedes vigilax (Skuse), and 1 each from Culex sitiens Wiedemann and Aedes alternans (Westwood). The RR virus minimum infection rate in mosquitoes ranged from 1.6 to 2.5/1,000 from March to June 1994. This study implicates freshwater and brackish water mosquitoes as important suburban vectors of RR virus and indicates the need for refocusing mosquito control priorities.

Occult choroidal neovascularization in age-related macular degeneration. A natural history study

OBJECTIVE

To explore morphological and vision changes in untreated eyes with subfoveal choroidal neovascularization (CNV) that have poorly demarcated boundaries.

DESIGN

Analysis of photographs of untreated patients with poorly demarcated occult CNV participating in a prospective clinical trial evaluating laser treatment compared with observation.

SETTING

Two tertiary retinal referral centers.

PATIENTS

Symptomatic individuals with poorly demarcated subfoveal occult CNV associated with age-related macular degeneration.

MAIN OUTCOME MEASURES

Change in size of lesion, development of classic CNV, change in vision, and development of subretinal fibrosis.

RESULTS

During follow-up (9-12 months), 32% of the occult choroidal neovascular lesions more than doubled their original size. Classic CNV developed in 52% of eyes that started without it. The median loss in visual acuity was 2.5 lines. Eyes with classic CNV or subretinal blood or both at baseline developed subretinal fibrosis more frequently and lost more visual acuity, but not to a statistically significant degree.

CONCLUSIONS

The morphological changes of eyes with subfoveal occult CNV in which the boundaries are poorly demarcated in variable; the presence of subretinal blood or a component of classic CNV may influence the prognosis for further loss of vision.

An outbreak of Japanese encephalitis in the Torres Strait, Australia, 1995

OBJECTIVES

To determine the distribution of virus infection during an outbreak of Japanese encephalitis (JE) in the Torres Strait, and to describe the environmental factors facilitating the outbreak.

DESIGN

Human and porcine serological surveys for JE virus activity throughout the Torres Strait, and mosquito and household surveys on the island of Badu.

SETTING

The island of Badu (where the clinical cases occurred) and the other islands of the Torres Strait, Australia, during April-May 1995.

RESULTS

The serological surveys identified recent JE virus infection among residents or domestic pigs on at least nine outer Torres Strait islands. A JE virus, confirmed by nucleotide sequencing, was isolated from two asymptomatic Badu residents. Virus isolations and mosquito surveys implicated Culex annulirostris as the major vector involved in the outbreak. There was prolific Cx. annulirostris breeding in a variety of water bodies close to and within the Badu community. Over half (53%) of the households kept pigs in pens, and many (63%) of the pigpens were situated near standing water; in 56% of these "wet" pigpens Cx. annulirostris was breeding.

CONCLUSIONS

There was evidence of widespread JE virus activity throughout the outer islands of the Torres Strait. We suggest that migratory birds and/or wind-blown mosquitoes could have imported the virus into the Torres Strait from a focus of viral activity, possibly in Papua New Guinea, thereby initiating the outbreak. A combination of environmental factors, with large numbers of domestic pigs in close proximity to human dwellings and mosquito breeding sites, undoubtedly facilitated the outbreak on Badu.

Recombinant Rhizobium meliloti strains with extra biotin synthesis capability

The growth of Rhizobium meliloti 1021 in an experimental alfalfa (Medicago sativa L.) rhizosphere was stimulated by adding nanomolar amounts of biotin. To overcome this biotin limitation, R. meliloti strains were constructed by conjugating the Escherichia coli biotin synthesis operon into biotin auxotroph R. meliloti 1021-B3. Transconjugant strains Rm1021-WS10 and Rm1021-WS11 grew faster in vitro and achieved a higher cell density than did R. meliloti 1021 and overproduced biotin on a defined medium. The increase in cell yield was associated with as much as a 99% loss in viability for Rm1021-WS11, but data suggested that a separate stabilizing factor in the E. coli DNA reduced cell death in Rm1021-WS10. In rhizosphere tests, the recombinant strains showed delayed growth and competed poorly against Rm1021.

Biotin and other water-soluble vitamins are key growth factors for alfalfa root colonization by Rhizobium meliloti 1021

Rhizosphere growth limitations imposed on Rhizobium meliloti by availability of biotin, thiamine, and riboflavin were overcome by adding nanomolar amounts of these vitamins. Studies done with R. meliloti 1021 showed that both synthesis and uptake of biotin promote colonization of alfalfa roots. Two lines of evidence indicated that plant-derived biotin normally promotes root colonization: (i) adding avidin significantly (P < or = 0.01) reduced rhizosphere growth of R meliloti 1021, and (ii) growth of Tn5-induced biotin auxotrophs still increased 10-fold in the rhizosphere. Synthesis, however, is the more important source of biotin for R. meliloti 1021 because in root colonization tests biotin auxotrophs competed very poorly with the parent strain. Mutations conferring biotin auxotrophy were closely linked on a single restriction fragment, and one was complemented with the Escherichia coli bio operon. Initial nucleotide sequencing and DNA-DNA hybridization tests showed the biotin synthesis genes in R. meliloti are quite different from those in E. coli.

Midfacial degloving for the management of nasal, sinus, and skull-base neoplasms

The midfacial degloving approach to the midfacial orbital and anterior skull base structures is very versatile. It provides excellent access to a wide range of resections, such as medial maxillectomy, radical maxillectomy with and without orbital exenteration, anterior skull base cranifacial resection, and partial rhinectomy. This technique is useful for removal of benign and malignant lesions. The postoperative complications are rare. Because of absence of external skin incisions the cosmetic results are excellent.

Suppression of an Isoflavonoid Phytoalexin Defense Response in Mycorrhizal Alfalfa Roots

Isoflavonoids and steady-state mRNA levels of phenylalanine ammonia-lyase, chalcone isomerase, and isoflavone reductase were followed during a rapid, nearly synchronous infection of alfalfa (Medicago sativa L.) roots by the vesicular arbuscular fungus Glomus intraradices (Schenck & Smith) to test whether previously indicated suppression of the host defense response is regulated by changes in the steady-state mRNA level. Relative amounts of steady-state phenylalanine ammonia-lyase mRNA in the mycorrhizal roots doubled between d 14 and 18 and then immediately declined by 75% to reach and maintain a value lower than the control roots through d 21. Relative levels of chalcone isomerase mRNA in the inoculated roots increased 6-fold between d 14 and 17 and then decreased rapidly to the control level. Isoflavone reductase mRNA was not induced by mycorrhizal colonization. High-performance liquid chromatography, proton-nuclear magnetic resonance, and fast atom bombardment-mass spectrometry analyses showed consistent increases in formononetin levels and transient increases in medicarpin-3-O-glycoside and formononetin conjugates in the inoculated roots when colonization began. As colonization increased, levels of formononetin conjugates declined in mycorrhizal roots below those in uncolonized controls. Medicarpin aglycone, an alfalfa phytoalexin normally associated with pathogenic infections, was not detected at any stage. These findings supply detailed evidence that, during early colonization of plant roots by symbiotic Glomus, defense transcripts are induced and then subsequently suppressed.

Plant isoflavonoids, pathogens and symbionts

It has recently been discovered that when symbiotic Rhizobium and Bradyrhizobium cells are outside the plant they are also exposed to the isoflavonoid phytoalexins that are normally associated with pathogenic infections. How the symbionts elicit and respond to isoflavonoids may help to define the mechanisms that are used by other beneficial soil microorganisms to colonize plant roots.

Child care for children in poverty: opportunity or inequity?

Data from a nationally representative survey of child care centers and a 5-site, observational study of centers were used to examine the quality of care provided to children from low-income families. Comparisons were made to a national sample of centers; among Head Start, public school-sponsored, and other community-based subsidized centers; and among centers that served families from differing socioeconomic groups. The quality of care in centers that served predominantly low-income children was adequate, but highly variable, with structural indices exhibiting higher quality than observations of global quality and of staff-child interactions. When compared to Head Start and public school-sponsored centers, the community-based centers had smaller groups and fewer children per teacher for preschoolers, but also had less well educated and compensated staff. Centers that predominantly served children from upper-income families provided the highest quality of care across multiple indices, and those that predominantly served children from middle-income families almost uniformly provided the poorest quality of care. The centers that served children from low-income families did not differ significantly in quality from the upper-income centers on most indices. However, the teachers in these programs were observed to be less sensitive and more harsh than teachers in the centers that served more advantaged families. The implications of the findings for research and policy are discussed.

Alfalfa (Medicago sativa L.) Root Exudates Contain Isoflavonoids in the Presence of Rhizobium meliloti

Root exudates of alfalfa (Medicago sativa L.) inoculated with symbiotic Rhizobium meliloti bacteria contained three isoflavonoids that were not found in exudates of uninoculated plants. Data from proton nuclear magnetic resonance, mass spectrometry, and ultraviolet-visible absorbance analyses indicated that root exudates of inoculated plants contained aglycone and glycoside forms of the phytoalexin medicarpin and a formononetin-7-O-(6"-O-malonylglycoside), a conjugated form of the medicarpin precursor formononetin. The medicarpin molecules did not induce nod gene transcription in R. meliloti, but the formononetin-7-O-(6"-O-malonylglycoside) induced nod genes regulated by both NodD1 and NodD2 proteins in R. meliloti. Hydrolysis of either the malonyl or the glycosyl linkage from the formononetin conjugate eliminated nod gene-inducing activity. The nod gene-inducing activity of crude root exudates was increased 200 and 65% upon inoculation with R. meliloti or R. leguminosarum bv phaseoli, respectively. When root exudate from uninoculated alfalfa was incubated with R. meliloti, high performance liquid chromatography analyses showed no evidence that bacterial metabolism produced medicarpin. These results indicate that alfalfa responds to symbiotic R. meliloti by exuding a phytoalexin normally elicited by pathogens and that the microsymbiont can use a precursor of the phytoalexin as a signal for inducing symbiotic nod genes.

Combined effects of urokinase and heparin on PTT values during thrombolytic therapy

The local infusion of urokinase may be complicated by hemorrhage. Except for maintaining fibrinogen levels above 100 mg/dL, no other criteria exist for titrating the dose of urokinase to avoid hemorrhagic complications. A retrospective examination of the fibrinolytic and coagulation states was performed on 11 patients receiving local high-dose urokinase (240,000 U/hr) and heparin for thrombolysis of acute occlusions to identify parameters other than fibrinogen levels that may correlate with bleeding complications. Five patients experienced bleeding complications, 3 of whom had partial thromboplastin time (PTT) values greater than 150 seconds. None of the five patients having hemorrhagic complications had fibrinogen levels below 100 mg/dL at any time. Urokinase began to enhance the effect of heparin on PTT values as a result of reducing fibrinogen levels. In 10 of 11 patients this effect caused PTT values to at least double when compared with heparin alone. This substantial rise in PTT occurred only after fibrinogen levels approached 200 mg/dL in 8 of 11 patients. Although the number of patients is small, these data suggest that when heparin is used during thrombolysis, closer PTT monitoring should be carried out as fibrinogen levels begin to decline, especially when they approach 200 mg/dL, to avoid excessive PTT elevations and subsequent bleeding.

Beyond beliefs: parent and child behaviors and children's perceived academic competence

Examined the relations of parent and child behaviors with children's perceptions of their academic competence. 74 high-achieving third-grade children, with varying levels of perceived academic competence, were observed working with mothers and fathers both on solvable tasks (Period 1) and during a period that included some unsolvable tasks (Period 2). Results indicated that children's perceived academic competence was positively related to father warmth, both at Period 1 and at Period 2. Children's perceived academic competence was also positively related to their own behavior when working with fathers at Period 2. Specifically, children with higher perceived academic competence showed more emotional restraint and were more self-reliant when working on tasks at Period 2 than were children with lower perceived academic competence. The results indicate that there are systematic, observable correlates of children's self-reports of their perceived academic competence.

Isolation of Kunjin virus from a patient with a naturally acquired infection

OBJECTIVE

To describe the first isolation of Kunjin virus from a patient with a natural infection.

CLINICAL FEATURES

A 48-year-old female egg collector presented with muscle weakness, fatigue and extreme lethargy three weeks after developing rigors, headache, photophobia and nausea. Kunjin virus was isolated from an acute phase serum sample.

INTERVENTION AND OUTCOME

The patient made a partial recovery after treatment for 10 days with Catovit (Boehringer Ingelheim), one tablet twice a day, and then declined further medical contact.

CONCLUSION

The isolation of Kunjin virus from this patient confirms previous serological observations which suggested that this mosquito-borne virus caused febrile episodes in humans accompanied, on occasion, by polyarthralgia or mild central nervous system signs and symptoms.

Trigonelline and Stachydrine Released from Alfalfa Seeds Activate NodD2 Protein in Rhizobium meliloti

Spectroscopic data (nuclear magnetic resonance, mass spectrometry, ultraviolet-visible) in this study identify trigonelline and stachydrine as major components of alfalfa (Medicago sativa L.) seed rinse. Moreover, biological assays show that these natural products induce nodulation (nod) gene transcription in Rhizobium meliloti by activating the regulatory protein NodD2, but not the homologous NodD1 protein. These findings contrast with the fact that the only previously identified NodD2 activator, 4,4' -dihydroxy-2' -methoxychalcone (MCh), also activates NodD1 protein. Trigonelline and stachydrine induce nod genes only at much higher concentrations than MCh, but they are released from seeds in correspondingly greater amounts. The existence of these amphoteric, nonflavonoid nod gene inducers broadens our understanding of the biochemical processes and ecological mechanisms that a legume host uses to regulate its microbial symbiont.

Thresholds of quality: implications for the social development of children in center-based child care

We assessed the quality of center child care relationships with adults and peers for 414 children (ages 14 to 54 months). Classrooms were classified by ratio and group size provisions of the Federal Interagency Day Care Requirements (FIDCR) and by the Early Childhood and Infant and Toddler Environmental Rating Scales. Children cared for in classrooms meeting FIDCR ratios were more likely to be in classrooms rated as good or very good in caregiving and activities. Children in classrooms rated as good or very good in caregiving were more likely to be securely attached to teachers. Securely attached children were more competent with peers. Children cared for in classrooms meeting FIDCR group size were more likely to be in classrooms rated higher in activities. Children in classrooms rated high in activities were likely to orient to both adults and peers. Children with social orientations to adults and peers were more competent with peers.

Traumatic aortic tear: screening with chest CT

Dynamic chest computed tomography (CT) was performed in 326 patients who had undergone abdominal CT for blunt trauma to evaluate the role of chest CT in screening for thoracic aortic injury. Evidence of mediastinal bleeding constituted an abnormal CT examination. The results were correlated with those from aortography in 131 patients. The chest radiographs were abnormal in 127 patients (39%). Of those 127 patients, chest CT scans were abnormal in 39 patients; an aortic tear was present in eight of those patients (21%). The remaining 88 patients had normal CT scans and no aortic injury. Of the 199 patients with normal radiographs, 15 had abnormal CT scans and 184 had normal CT scans and no aortic injury. There were no false-negative CT scans; 79% of patients with normal CT scans had false-positive chest radiographs. With CT there was a significant improvement over plain radiography in specificity, accuracy, and predictive value of positive results. If chest CT were used as an adjunct to chest radiography in the screening for traumatic aortic tear, the need for aortography would decrease by 56%. Chest CT can safely help discriminate candidates for aortography, is cost-effective, and, in hemodynamically stable patients, should be incorporated in the screening for traumatic aortic tear.

Rhizobium nod Gene Inducers Exuded Naturally from Roots of Common Bean (Phaseolus vulgaris L.)

Four compounds exuded from young roots of a black-seeded bean (Phaseolus vulgaris L., cv PI165426CS) induce transcription of nod genes in Rhizobium leguminosarum biovar phaseoli. The three most active nod gene inducers were identified by spectroscopic methods (ultraviolet/visible absorbance, proton nuclear magnetic resonance, and mass spectrometry) as being eriodictyol (5,7,3',4' -tetrahydroxyflavanone), naringenin (5,7,4' -trihydroxyflavanone), and a 7-O-glycoside of genistein (5,7,4' -trihydroxyisoflavone). Comparisons with authentic standards verified the chemical structures of the aglycones and their capacity to induce beta-galactosidase activity in R. leguminosarum strains containing nodA-lacZ or nodC-lacZ fusions controlled by R. leguminosarum biovar phaseoli nodD genes. Roots of 9-day-old seedlings released 42, 281, and 337 nanomoles per plant per day of genistein, eriodictyol, and naringenin, respectively. Genistein and naringenin induced higher maximum beta-galactosidase activities and required lower concentrations for half-maximum induction than eriodictyol. Comparing the nod gene-inducing activity of seed rinses with root exudate from PI165426CS bean showed that root flavonoids were released at about 6% the rate of those from seeds on a molar basis, but on average the individual compounds from roots were approximately three times more active than nod gene inducers from seeds.

Anthocyanidins and Flavonols, Major nod Gene Inducers from Seeds of a Black-Seeded Common Bean (Phaseolus vulgaris L.)

Eleven compounds released from germinating seeds of a black-seeded bean (Phaseolus vulgaris L., cv PI165426CS) induce transcription of nod genes in Rhizobium leguminosarum biovar phaseoli. Aglycones from 10 of those compounds were identified by spectroscopic methods (ultraviolet/visible, proton nuclear magnetic resonance, and mass spectroscopy), and their biological activities were demonstrated by induction of beta-galactosidase activity in R. leguminosarum strains containing nodA-lacZ or nodC-lacZ fusions controlled by R. leguminosarum biovar phaseoli nodD genes. By making comparisons with authentic standards, the chemical structures for aglycones from the 10 molecules were confirmed as being anthocyanidins (delphinidin, petunidin, and malvidin) and flavonols (myricetin, quercetin, and kaempferol). All anthocyanidins and flavonols had 3-O-glycosylation and free hydroxyl groups at the 4', 5, and 7 positions. Hydrolysis experiments showed that the mean concentration required for half-maximum nod gene induction (I(50)) by the 10 glycosides was about half that of the corresponding aglycones. The mean I(50) value for the three anthocyanidins (360 nanomolar) was less (P </= 0.05) than that of the three flavonol aglycones (980 nanomolar). Each seed released approximately 2500 nanomoles of anthocyanidin and 450 nanomoles of flavonol nod gene inducers in conjugated forms during the first 6 hours of imbibition. Based on amounts and activities of the compounds released, anthocyanins contributed approximately 10-fold more total nod-inducing activity than flavonol glycosides. These anthocyanidins from bean seeds represent the first nod-inducing compounds identified from that group of flavonoids.

Gastric tonometry and venous oximetry in cardiac surgery patients

OBJECTIVE

To determine the relationship between gastric intramucosal pH and several other indices of splanchnic perfusion in patients undergoing cardiopulmonary bypass.

DESIGN

Prospective, single-arm study.

SETTING

University Hospital.

METHODS

Elective cardiac surgery patients (n = 8), free of hepatic disease, were studied. Before anesthetic induction, a triple-lumen, heparin-bonded fiberoptic catheter was inserted into the hepatic vein under fluoroscopic guidance. An identical catheter was inserted into the pulmonary artery. After endotracheal intubation, a nasogastric tube modified to permit measurement of gastric intramucosal pH was inserted into the stomach. Systemic oxygen delivery (DO2), and arterial, mixed venous, hepatic venous, and femoral venous blood gases and lactate concentrations were recorded at the following times: immediately before induction of anesthesia (time 1); during atrial cannulation (time 2); after 30 mins of hypothermic cardiopulmonary bypass (time 3); 15 mins after termination of cardiopulmonary bypass (time 4); and 1 hr after arrival in the ICU (time 5). Hepatic venous hemoglobin saturation (SO2) and mixed venous hemoglobin saturation (SvO2) were monitored continuously from times 1 to 5. Gastric intramucosal pH was recorded at times 2, 3, 4, and 5. The hepatic catheter was removed as soon as the last samples were collected in the ICU.

RESULTS

The square of the weighted mean correlation coefficients (rw)2 for gastric intramucosal pH vs. hepatic venous lactate concentrations, gastric intramucosal pH vs. hepatic venous PO2, and gastric intramucosal pH vs. hepatic venous pH were (rw)2 = .50, (rw)2 = .58, and (rw)2 = .32, respectively. Systemic DO2, hepatic venous lactate concentrations, hepatic venous PO2, and hepatic venous pH were significant determinants in the multiple regression model for gastric intramucosal pH (r2 = .89). There were significant differences between SvO2 and hepatic venous SO2 at times 4 and 5.

CONCLUSION

Gastric intramucosal pH may provide a minimally invasive way to monitor the adequacy of splanchnic DO2 in patients undergoing cardiopulmonary bypass. Additional data are necessary to determine whether low gastric intramucosal pH is truly a marker of supply-dependent oxygen uptake across the hepatosplanchnic vascular bed under these conditions.