Factors affecting carriage and intensity of infection of Calodium hepaticum within Norway rats (Rattus norvegicus) from an urban slum environment in Salvador, Brazil.

Urban slum environments in the tropics are conducive to the proliferation and the spread of rodent-borne zoonotic pathogens to humans. Calodium hepaticum (Brancroft, 1893) is a zoonotic nematode known to infect a variety of mammalian hosts, including humans. Norway rats (Rattus norvegicus) are considered the most important mammalian host of C. hepaticum and are therefore a potentially useful species to inform estimates of the risk to humans living in urban slum environments. There is a lack of studies systematically evaluating the role of demographic and environmental factors that influence both carriage and intensity of infection of C. hepaticum in rodents from urban slum areas within tropical regions. Carriage and the intensity of infection of C. hepaticum were studied in 402 Norway rats over a 2-year period in an urban slum in Salvador, Brazil. Overall, prevalence in Norway rats was 83% (337/402). Independent risk factors for C. hepaticum carriage in R. norvegicus were age and valley of capture. Of those infected the proportion with gross liver involvement (i.e. >75% of the liver affected, a proxy for a high level intensity of infection), was low (8%, 26/337). Sixty soil samples were collected from ten locations to estimate levels of environmental contamination and provide information on the potential risk to humans of contracting C. hepaticum from the environment. Sixty percent (6/10) of the sites were contaminated with C. hepaticum. High carriage levels of C. hepaticum within Norway rats and sub-standard living conditions within slum areas may increase the risk to humans of exposure to the infective eggs of C. hepaticum. This study supports the need for further studies to assess whether humans are becoming infected within this community and whether C. hepaticum is posing a significant risk to human health.

Self-reported health-related quality of life in kindergarten children: psychometric properties of the Kiddy-KINDL.

OBJECTIVES: To assess the psychometric properties of the German self-reported version of the Kiddy-KINDL that measures Health Related Quality of Life (HRQoL) in 3 to 5 year old kindergarten children. STUDY DESIGN: The population of the study comprised baseline data of a longitudinal study whose main aim is to investigate self-reported health outcomes in young children (N = 317). METHODS: Missing values, the distribution of data, internal consistency (Cronbach's alpha and Guttman's lambda), and reliability (split half and two weeks test-retest) were analysed. To assess discriminant validity, mean differences were tested splitting the sample regarding socio-emotional competences (VBV 3-6), age and gender. Structural validity was investigated with Confirmatory Factor Analysis (CFA). RESULTS: Mean HRQoL was 69.79 (SD 16.84). Overall missing values were 8.1%, overall Cronbach's alpha was 0.75 and overall Guttman's lambda was 0.77; for the whole scale Spearman-Brown test for split half reliability resulted in 0.80 and ICC for test-retest in 0.83. Discriminant validity investigation differentiated groups with high and low socio-emotional competence and those children who were 4.5 years or older, compared to the younger ones. Differences between boys and girls were also found. CFA suggested two main dimensions: physical and socio-emotional. CONCLUSION: This preliminary validation of the Kiddy-KINDL in very young children shows satisfactory psychometric properties. However, results of the Cronbach's alpha, Guttman's lambda and the CFA depicted problems, mainly in the psychological dimension. Due to these we recommend to use the Kiddy-KINDL as an instrument with only two dimensions. Further studies in general population samples are needed.

Complex ventral hernia repair with a human acellular dermal matrix.

PURPOSE: The ideal approach to complex ventral hernia repair is frequently debated. Differences in processing techniques among biologic materials may impact hernia repair outcomes. This study evaluates the outcomes of hernia repair with a terminally sterilized human acellular dermal matrix (TS-HADM) (AlloMax(®) Surgical Graft, by C. R. Bard/Davol, Inc., Warwick, RI, USA) treated with low-dose gamma irradiation. METHODS: A single-arm multi-center retrospective observational study of patients undergoing hernia repair with TS-HADM was performed. Data analyses were exploratory only; no formal hypothesis testing was pre-specified. RESULTS: Seventy-eight patients (43F, 35M) underwent incisional hernia repair with a TS-HADM. Mean follow-up was 20.5 months. Preoperative characteristics include age of 56.6 ± 11.1 years, BMI 36.7 ± 9.9 kg/m(2), and mean hernia defect size 187 cm(2). Sixty-five patients underwent component separation technique (CST) with a reinforcing graft. Overall, 21.8% developed recurrences. Recurrences occurred in 15% of patients repaired with CST. Major wound complications occurred in 31% of patients overall. Based upon CDC surgical wound classification, major wound complications were seen in 26, 40, 56, and 50% of Class 1, 2, 3, and 4 wounds, respectively. No grafts required removal. CONCLUSIONS: Hernia recurrences are not uncommon following complex abdominal wall reconstruction. Improved outcomes are seen when a TS-HADM is utilized as reinforcement to primary fascial closure.

Composition of cuticular lipids in the pteromalid wasp Lariophagus distinguendus is host dependent.

The insect cuticle is covered by a thin layer of hydrocarbons not only preventing desiccation but also playing an important role in the sexual communication of several species. In the pteromalid wasp Lariophagus distinguendus, a parasitoid of grain infesting beetles, female cuticular hydrocarbons (CHCs) elicit male courtship behaviour. We analyzed the CHC profiles of male and female L. distinguendus wasps reared on different beetle hosts by coupled gas chromatography- mass spectrometry (GC-MS). Statistical analysis of the data revealed significant differences between strains reared on different hosts, while spatially isolated strains reared on the same host produced similar profiles. CHC profiles of parasitoids reared on Stegobium paniceum were statistically distinguishable from those of wasps reared on all other hosts. A host shift from Sitophilus granarius to S. paniceum resulted in distinguishable CHC profiles of L. distinguendus females after only one generation. Considering the role of CHCs as contact sex pheromones, our data suggest that host shifts in parasitic wasps might lead to reproductive isolation of host races due to the modification of the cuticular semiochemistry.

Electron bunch timing with femtosecond precision in a superconducting free-electron laser.

High-gain free-electron lasers (FELs) are capable of generating femtosecond x-ray pulses with peak brilliances many orders of magnitude higher than at other existing x-ray sources. In order to fully exploit the opportunities offered by these femtosecond light pulses in time-resolved experiments, an unprecedented synchronization accuracy is required. In this Letter, we distributed the pulse train of a mode-locked fiber laser with femtosecond stability to different locations in the linear accelerator of the soft x-ray FEL FLASH. A novel electro-optic detection scheme was applied to measure the electron bunch arrival time with an as yet unrivaled precision of 6 fs (rms). With two beam-based feedback systems we succeeded in stabilizing both the arrival time and the electron bunch compression process within two magnetic chicanes, yielding a significant reduction of the FEL pulse energy jitter.

Mental health and illness in Boston's children and adolescents: one city's experience and its implications for mental health policy makers.

In 1999, the Boston Public Heath Commission used data from a variety of sources to explore the level of mental health disturbance in Boston's children and adolescents. Data for 1997 from the Youth Risk Behavior Survey showed that about 20% of Boston public high school students had ever experienced suicidal ideation, while approximately 10% had actually attempted suicide. About one in five teenage respondents to the Boston Youth Survey said they were frequently depressed. While females were more likely to report depression, males were more likely to report isolation and less likely to consider counseling. Medicaid claims data revealed differences by gender and age, with males using psychiatric emergency and Medicaid mental health services more than females, and 10- to 15-year-olds using these services more than other age groups. Emergency room injury surveillance and death certificate data indicated that among children and adolescents, females were twice as likely to attempt suicide as males, although males were more likely to complete a suicide. This data analysis helped pinpoint areas of need and has proven useful in the development of a child and adolescent mental health action agenda. Efforts to date have included expansion of surveillance, legislative advocacy, coalition building, and new services. Key indicators including suicidal ideation and attempts, service utilization, and service capacity have been chosen as markers for future improvement.

Listening to youth: teen perspectives on pregnancy prevention.

PURPOSE: To ascertain views of public high school students on preventing teen pregnancy. The authors hypothesized that students at varying risk for pregnancy (e.g., abstinent, consistent contraceptors, inconsistent contraceptors) would have differing views which would have implications for future pregnancy prevention programming. METHODS: A 75-question anonymous survey designed for this study was administered in six Boston high schools. The sample consisted of 49% females and 51% males in 10th and 11th grades from diverse racial and ethnic backgrounds. One thousand surveys were received and analyzed using Chi-square tests to assess statistically significant differences in student responses. RESULTS: Sixty-three percent of the students had had sexual intercourse: 72% of males and 54% of females. Of these, 35% were consistent contraceptors and 65% were inconsistent. Students believed that having more information on pregnancy and birth control (52%), education about relationships (33%), parental communication (32%), improved contraceptive access (31%), and education about parenting realities (30%) would prevent teen pregnancy. Abstinent teens were more likely (58%) to say that information on pregnancy and birth control was important (p<.05), whereas consistently contracepting teens were more likely (40%) to identify greater access to birth control (p <.01). Males were more likely than females to prefer their information on contraception from parents (23% vs. 18%) and health education classes (16% vs. 7.5%), whereas females were more likely than males to prefer the health arena (51% vs. 27%) (p<.001). Teens using contraception were also more likely to be having frequent conversations with parents (49%) (p<.001). When asked why they had not used contraception, inconsistent contraceptors were more likely than others to say that they never thought of it (15%) (p<.001). CONCLUSIONS: Teens report that having more information from parents, school, and health arenas can prevent pregnancy. Abstinent, consistent contraceptors, and inconsistent contraceptors have different preferences regarding strategies. This information has important implications for educational content and policy discussions.

PIP: This survey determined the views of public high school students on teen pregnancy prevention. The authors hypothesized that students at varying risk for pregnancy would have differing views, which would have implications for future pregnancy prevention programming. A 75-question anonymous survey was designed and administered in 6 Boston high schools. A total of 1000 10th- and 11th-grade students from diverse racial and ethnic backgrounds completed the questionnaire. The overall analysis showed that 63% of the students had had sexual intercourse: 72% of males and 54% of females. Among these, 35% were consistent contraceptors and 65% were inconsistent. Teens enumerated the factors that will prevent teen pregnancy. These include having more information on pregnancy and birth control (52%), education about relationships (33%), parental communication (32%), improved contraceptive access (31%), and education about parenting realities (30%). Moreover, abstinent, consistent contraceptors, and inconsistent contraceptors had different preferences regarding strategies. Such findings have important implications for educational content and policy discussions.

School-based health centers and school nurses: cementing the collaboration.

As school health personnel respond to the changing needs of children, new models are being developed and traditional models are being reexamined. The role of the school nurse is expanding at the same time as school-based health centers are increasing in number. Partnerships between school-based health centers and school nurses are critical for the success of school-based health centers, and partnerships will enhance and expand roles for school nurses. This paper clarifies the role of each in three areas: collaboration, communication, and cooperation. In addition, obstacles to partnerships are examined. The goal of this collaboration is a shared vision for the continuum of school health services in which school nurse and school health center serve integral roles. Elements for successful collaboration between nurse and health center are reviewed, including clarifying roles, shared leadership and program ownership, cooperative training and continuing education, negotiating conflict, and most importantly, maintaining mutual support and respect.

A hexameric helicase encircles one DNA strand and excludes the other during DNA unwinding.

The bacteriophage T7 DNA helicase/primase (gene 4 protein) is a ring-like hexamer that encircles ssDNA and requires forked DNA to catalyze DNA unwinding. We report that optimal rates of unwinding of forked DNA require ssDNA tails of 55 nucleotides on the 5'-to-3' strand and 15 nucleotides on the 3'-to-5' strand. Surprisingly, streptavidin bound to a biotinylated 3'-end fully substitutes for the 3'-to-5' ssDNA tail. This suggests that excluding the 3'-to-5' DNA strand from the center of the helicase is an essential aspect of the mechanism of hexameric helicase-catalyzed DNA unwinding. We also report that streptavidin bound to a biotinylated dT within the 5'-to-3' strand of the duplexed region abolishes DNA unwinding; whereas, streptavidin bound to a biotinylated dT within the duplexed region of the other strand has no effect. These results unambiguously demonstrate that the T7 gene 4 protein is a 5'-to-3' helicase and imply that during DNA unwinding the 5'-to-3' strand transverses the center of the ring while the 3'-to-5' strand is excluded from the center of the ring. Implications for collisions between a helicase and other protein-DNA complexes are discussed.

Role of school-based health centers in referral completion.

PURPOSE: This study examined referrals from School-based health centers (SBHCs) to a sponsoring hospital to determine factors influencing successful referral completion and to assess SBHCs' ability to coordinate care. METHODS: A total of 138 referrals from eight SBHCs to Boston City Hospital between September 1993 and October 1994 were reviewed via medical records, clinic logs, and hospital registration system. A data extraction tool was used to collect information. Statistical analyses were performed to identify associations between referral completion and study variables. RESULTS: Seventy-five percent of all referrals were completed: 55.4% on the first attempt. Forty-six percent of those referred a second time completed their referrals. Statistically significant associations between referral completion and reason for referral (p = 0.01), visit diagnosis (p = 0.005), and usual source of health care (p = 0.009) were found. Provider documentation, including referral log and patient chart, was also associated with referral completion. Neither gender, race, nor health insurance had any significant association with successful referrals. CONCLUSIONS: This study suggests that SBHCs can significantly contribute to coordinated care for adolescents, especially for the uninsured and those without a source of health care. SBHCs were particularly effective at facilitating referral to specific services including: family planning, tuberculosis prophylaxis, and subspecialty care. Provider action, such as making appointments and documentation, was also an important factor.

Integrating school-based health centers into managed care in Massachusetts.

Contemporary school-based health centers (SBHCs) face dwindling financial resources and pressures to maximize reimbursement. As managed care becomes the dominant system of health care financing, SBHCs must integrate their service delivery with managed care systems. In Massachusetts, through a combination of advocacy, state, and local collaboration, SBHCs successfully developed partnerships with managed care plans. Strategies include enhancing communication between SBHCs and health maintenance organizations, standardizing school-based care, and mandating integration of services through state contract language. This article delineates the process that occurred and key elements necessary for developing these relationships. This experience is a valuable resource for other states and school-based providers as Medicaid populations are funneled into managed care arrangements.

Lateral Neck Mass in an Adolescent Athlete.

A 17-year-old African-American athlete presented with complaints of allergies. He had a history of seasonal allergic rhinitis and otorrhea for many years, but this time it was accompanied by right-sided neck swelling. His right sternocleidomastoid was slightly enlarged, soft, nontender, and no discrete masses were palpable. He was active in shot-put and was right-handed. Following discharge with antihistamine therapy, he returned a month later with a visible enlargement of the right lateral neck and bilateral cervical adenopathy. The biopsy of the nasopharyngeal mass revealed an undifferentiated squamous nasopharyngeal carcinoma, staged at T2N3MX. Chemotherapy followed by radiation was recommended.

A nationwide survey of school health services delivery in urban schools.

To understand school health service delivery models, and to plan for reorganization of a local school health service, a telephone survey of school-based health programs from around the country was conducted in 1992. Responses were elicited from 33 school departments in some of the largest American cities. Respondents described their current programs, obstacles they face, and approaches they have chosen to address the needs of urban schoolchildren. City size did affect amount of services provided overall, but a clear relationship existed between number of providers employed, and the number/amount of screening services available. Cities employed a range of strategies to enhance services, including collaboration with local health authorities, creation of school clinics, and billing for services.

The slow dissociation of the T4 DNA polymerase holoenzyme when stalled by nucleotide omission. An indication of a highly processive enzyme.

We have developed an experimental assay to monitor the rate of dissociation of the T4 DNA polymerase holoenzyme (polymerase plus gene 44/62 and 45 proteins) once it has been stalled by nucleotide omission. Using this assay, we determined that the dissociation of the DNA polymerase holoenzyme follows a first order decay with a half-life of 2.5 min. The long half-life resembles that expected for the holoenzyme processively synthesizing DNA on the leading strand of the replication fork. The holoenzyme dissociation rate is independent of polymerase accessory protein concentration and of ATP hydrolysis. The dissociation rate is increased if the gene 32 protein is omitted or if the primer-template region is shortened from 46 to 28 base pairs. But the rate of holoenzyme dissociation is most strikingly increased when the circular DNA template is converted to a linear form. By analogy with other well studied systems, these results support a model in which ATP hydrolysis by the 44/62 proteins serves to load a ring-like 45 protein onto the DNA. Once loaded, the 45 protein, possibly along with the 44/62 complex, acts as a sliding clamp that tethers the DNA polymerase to the template.

The rapid dissociation of the T4 DNA polymerase holoenzyme when stopped by a DNA hairpin helix. A model for polymerase release following the termination of each Okazaki fragment.

We have examined the molecular mechanism that enables the T4 bacteriophage DNA polymerase holoenzyme to synthesize DNA processively on the leading strand of the replication fork for many minutes, while allowing an identical holoenzyme on the lagging strand to recycle from one Okazaki fragment to the next in less than 4 s. We use a perfect hairpin helix of 15 base pairs to mimic the encounter of the polymerase with the end of a previously synthesized Okazaki fragment. Polymerase dissociation is monitored during the stall at the hairpin helix by the addition of excess T4 gene 32 protein (SSB protein), which rapidly melts the helix and allows a stalled polymerase molecule to continue DNA synthesis. In the accompanying paper, we show that polymerase holoenzyme dissociation is slow (half-life of 2.5 min) when this enzyme is stalled by nucleotide omission (Hacker, K. J., and Alberts, B. M. (1994) J. Biol. Chem. 269, 24209-24220). In contrast, the holoenzyme dissociates with a half-life of 1 s after hitting the hairpin helix, a rate sufficient to allow efficient polymerase recycling on the lagging strand in vivo. We conclude that, upon completing each Okazaki fragment, the holoenzyme senses an encounter with duplex DNA and then switches to a state that rapidly dissociates.

Evidence for cytoprotection by prostaglandin E1 with normothermic hepatic ischemia.

Although the liver is relatively resistant to normothermic ischemia, prolonged periods of inflow occlusion have produced evidence of hepatocyte injury. We have developed an animal model of liver ischemia using the pig and maintaining subtotal inflow (hepatic artery and portal vein) occlusion, allowing mesenteric portal decompression via patent portal veins through the caudate lobe, obviating the need for portosystemic shunting. This produced biochemical [aspartate transaminase (AST), lactate dehydrogenase (LDH)] and histopathologic evidence, using a microscopic grading system, of hepatocyte necrosis after 2 hr of normothermic ischemia. By administration of prostaglandin E1 (PGE1) prior to and during inflow occlusion, we have produced a statistically significant reduction in LDH (1085.9 +/- 413.5 U/liter compared to 669.1 +/- 161.4 U/liter) and AST (236.5 +/- 80.4 U/liter compared to 85.1 +/- 39.7 U/liter) (P < 0.05) between control and PGE1 animals 24 hr after reperfusion. Moreover, using the blinded microscopic grading system for hepatocellular necrosis, we have found significantly less (2.86 +/- 0.90 compared to 1.57 +/- 1.13, P < 0.01) necrosis when control and PGE1 animals were compared. Our experimental model supports the hypothesis that PGE1 exerts a cytoprotective effect during prolonged normothermic hepatic ischemia but does not aid in elucidating a mechanism for this effect.

DNA helicase requirements for DNA replication during bacteriophage T4 infection.

The lytic bacteriophage T4 uses multiple mechanisms to initiate the replication of its DNA. Initiation occurs predominantly at replication origins at early times of infection, but there is a switch to genetic recombination-dependent initiation at late times of infection. The T4 insertion-substitution system was used to create a deletion in the T4 dda gene, which encodes a 5'-3' DNA helicase that stimulates both DNA replication and recombination reactions in vitro. The deletion caused a delay in T4 DNA synthesis at early times of infection, suggesting that the Dda protein is involved in the initiation of origin-dependent DNA synthesis. However, DNA synthesis eventually reached nearly wild-type levels, and the final number of phages produced per bacterium was similar to that of the wild type. When the dda mutant phage also contained a mutation in T4 gene 59 (a gene normally required only for recombination-dependent DNA replication), essentially no DNA was synthesized. Recent in vitro studies have shown that the gene 59 protein loads a component of the primosome, the T4 gene 41 DNA helicase, onto DNA. A molecular model for replication initiation is presented that is based on our genetic data.

Overexpression, purification, sequence analysis, and characterization of the T4 bacteriophage dda DNA helicase.

The bacteriophage T4 dda protein is a 5'-3' DNA helicase that stimulates DNA replication and recombination reactions in vitro and seems to play a role in the initiation of T4 DNA replication in vivo. Oligonucleotide probes based on NH2-terminal amino acid sequence were used to precisely map the location of the dda gene on the T4 chromosome. Using polymerase chain reaction techniques, the dda gene was then cloned into an expression vector, and the overproduced protein was purified in two chromatography steps. Both the genomic and cloned dda genes were sequenced and found to be identical, encoding a protein of 439 amino acids. The dda protein contains amino acid sequences resembling those of other known helicases, and is most homologous to the Escherichia coli recD protein. Protein affinity chromatography was used to show a direct interaction between the dda protein and the T4 uvsX protein (a rec A-type DNA recombinase).