Urban minority youth swimming (in)ability in the United States and associated demographic characteristics: toward a drowning prevention plan.

OBJECTIVE: To examine swimming ability and variables associated with swimming for US inner-city, minority children. Empirical research on minority children's swimming ability is non-existent, and drowning rates for this population are high. DESIGN: Cross-sectional survey research. Descriptive statistics were produced. Multiple regression was applied using significant demographic variables by swimming ability. SETTING: Six US cities were chosen (Chicago, Illinois; Houston, Texas; Memphis, Tennessee; Miami, Florida; Oakland, California; Philadelphia, Pennsylvania). Young Men's Christian Association (YMCA) facilities were used to solicit subjects. SUBJECTS: A large sample (n = 1680) was gathered, which targeted poor, minority children. Parents of children aged 4-11 years and adolescents (12-17 years) completed surveys that research team members or trained YMCA staff supervised during non-swimming YMCA programmes. RESULTS: African-American respondents reported a 57.5% "at risk" (unable to swim or uncomfortable in deep end of pool) swimming ability. Hispanic/Latino children confirmed a 56.2% "at risk" level as compared with 30.9% for white subjects. Age, sex, child's lunch programme, parental education and race variables were all significantly (p<0.05) related to swimming ability. Regression analysis revealed that all demographic variables fell into a significant model (p<0.001) as predictor variables. CONCLUSIONS: Poor minority children, specifically African-American and Hispanic/Latino, are at a significant disadvantage concerning swimming ability. Female subjects were notably more "at risk" regarding their swimming ability than male subjects. Age, race and socioeconomic factors (lunch programme and parental education) were significantly associated with children who have low swimming ability.

Expression of a reporter gene after microinjection of mammalian artificial chromosomes into pronuclei of bovine zygotes.

The introduction of mammalian artificial chromosomes (ACs) into zygotes represents an alternative, more predictive technology for the production of recombinant proteins in transgenic animals. The aim of these experiments was to examine the effects of artificial chromosome microinjection into bovine pronuclei on embryo development and reporter gene expression. Bovine oocytes aspirated from 2-5 mm size follicles were matured in vitro for 22 hr. Mature oocytes were fertilized in vitro with frozen- thawed bull spermatozoa. Artificial chromosome carrying either beta-galactosidase (Lac-Z) gene or green fluorescence protein (GFP) gene were isolated by flow cytometry. A single chromosome was microinjected into one of the two pronuclei of bovine zygotes. Sham injected zygotes served as controls. Injected zygotes were cultured in G 1.2 medium for 7 days. Hatched blastocysts were cultured on blocked STO cell feeder layer for attachment and outgrowth of ICM and trophectoderm cells. The results showed a high zygote survival rate following LacZ-ACs microinjection (74%). However, the blastocyst development rate after 7 days of culture was significantly lower than that of sham injected zygotes (7.5 vs. 22%). Embryonic cells positive for Lac-Z gene were detected by PCR in three of nine outgrowth colonies. In addition, GFP gene expression was observed in 15 out of 85 (18%) embryos at the arrested 2-cell stage to blastocyst stage. Six blastocysts successfully outgrew, three outgrowths were GFP positive for up to 3 weeks in culture. We conclude that the methodology for artificial chromosome delivery into bovine zygotes could lead to viable blastocyst development, and reporter gene expression could be sustained during pre-implantation development.

Efficient in-vitro transfer of a 60-Mb mammalian artificial chromosome into murine and hamster cells using cationic lipids and dendrimers.

Non-integrating artificial chromosomes represent a potentially promising approach to ex-vivo and in-vivo gene therapy applications. These large vectors require an efficient means for delivery to target cells. We have evaluated a panel of twenty-one commercially available transfection agents for their ability to mediate the in-vitro transfer of a 60-Mb murine artificial chromosome consisting of mouse major satellite DNA and a payload including a marker gene (hygromycin B) and a reporter gene (lacZ). A rapid screening procedure utilizing iododeoxyuridine-incorporated artificial chromosomes facilitated the assessment of different transfection conditions. The results were confirmed by cytogenetic analysis of positively transfected clones. By transfecting both hamster lung fibroblast cells (V79-4) and murine connective tissue cells [L-M(TK-)], the best results were obtained using either Superfect (cationic dendrimer) or LipofectAMINE 2000 (cationic lipid) with protocols adapted for metaphase chromosome preparation. Transfection efficiencies of 10(-4)-10(-2) (0.01-1%) were routinely observed, and recipient cells were able to maintain expression of the reporter gene over the total length of the experiment. This represents a significant advance over our previous attempts at mass-transfection of artificial chromosomes using microcell fusion, where we routinely achieved efficiencies at least two orders of magnitudes less than reported here. These data are particularly noteworthy given that lipid-mediated gene transfer typically involves transfecting millions of plasmids (1 microg of DNA from a 5 kb plasmid is approximately 1.2 x 10(11) copies) to each cell whereas the much larger artificial chromosomes comprise only a one-to-one ratio, yet achieve transfection efficiencies of (10(-2)-10(-1)), that is, comparable to our results. These data suggest that artificial chromosomes containing therapeutic genes can be successfully delivered to target cells in vitro using well-established transfection agents.

Generation of transgenic mice and germline transmission of a mammalian artificial chromosome introduced into embryos by pronuclear microinjection.

We have generated transgenic mice by pronuclear microinjection of a murine satellite DNA-based artificial chromosome (SATAC). As 50% of the founder progeny were SATAC-positive, this demonstrates that SATAC transmission through the germline had occurred. FISH analyses of metaphase chromosomes from mitogen-activated peripheral blood lymphocytes from both the founder and progeny revealed that the SATAC was maintained as a discrete chromosome and that it had not integrated into an endogenous chromosome. To our knowledge, this is the first report of the germline transmission of a genetically engineered mammalian artificial chromosome within transgenic animals generated through pronuclear microinjection. We have also shown that murine SATACs can be similarly introduced into bovine embryos. The use of embryo microinjection to generate transgenic mammals carrying genetically engineered chromosomes provides a novel method by which the unique advantages of chromosome-based gene delivery systems can be exploited.

Mammalian artificial chromosome pilot production facility: large-scale isolation of functional satellite DNA-based artificial chromosomes.

BACKGROUND: A pilot production facility has been established to isolate mammillian artificial chromosomes at high purity by using flow cytometric techniques. Dicentric chromosomes have been generated by the targeted amplification of pericentric heterochromatic and centromeric DNA by activating the "megareplicator." Breakage of these dicentric chromosomes generates satellite DNA-based artificial chromosomes (SATAC) from 60 to 400 megabases. METHODS: For large-scale production, we have developed cell lines capable of carrying one or two SATACs. A SATAC, because of a high adenine-thymine (AT) composition, is easily identified and sorted by using chromomycin A3 and Hoechst 33258 stains and a dual laser high-speed flow cytometer. A prototype SATAC (60 megabases) has been characterized. The prototype SATAC has been isolated from an original rodent/human hybrid cell line and transferred by using modified microcell fusion into a CHO production cell line. RESULTS: Metaphase chromosomes from this production cell line were isolated in a modified polyamine buffer, stained, and sorted by using a modified sheath buffer that maintains condensed chromosomes. SATACs are routinely sorted at rates greater than 1 million per hour. Sorted SATACs have been transferred to a variety of cells by using microcell fusion technology and were found to be functional. CONCLUSIONS: By developing new SATAC containing cell lines with fewer numbers of chromosomes in conjunction with operating a high speed flow sorter we have effectively generated an efficient production facility geared purely for the isolation of SATACs.

Stability of a functional murine satellite DNA-based artificial chromosome across mammalian species.

A 60-Mb murine chromosome consisting of murine pericentric satellite DNA and two bands of integrated marker and reporter genes has been generated de novo in a rodent/human hybrid cell line (mM2C1). This prototype mammalian artificial chromosome platform carries a normal centromere, and the expression of its beta-galactosidase reporter gene has remained stable under selection for over 25 months. The novel chromosome was transferred by a modified microcell fusion method to mouse [L-M(TK-)], bovine (P46) and human (EJ30) cell lines. In all cases, the chromosome remained structurally and functionally intact under selection for periods exceeding 3 months from the time of transfer into the new host. In addition, the chromosome was retained in three first-generation tumours when L-M(TK-) cells containing the chromosome were xenografted in severe combined immunodeficiency mice. These data support that a murine satellite DNA-based artificial chromosome can be used as a functional mammalian artificial chromosome and can be maintained in vivo and in cells of heterologous species in vitro.

[Physical and psychological status of 60-70-year-old citizens of Bern with neurotic symptoms in childhood--a study over more than 50 years (Emmental cohort)]. / Körperliches und psychisches Befinden bei 60-70jährigen Bernerinnen und Bernern mit neurotischen Symptomen im Kindesalter--Eine Untersuchung über mehr als 50 Jahre (Emmental-Kohorte).

The present study was undertaken to assess the influence of childhood variables (physical and emotional) to later well-being in a group of rural Swiss (Emmental Cohort). Our study is the first prospective cohort over a time period of more than 50 years. It includes 1537 children who were listed and assessed in 1942 (T1) because they had difficulties in school or were otherwise behaviorally disturbed. In 1995 (T2) more than 60% of the initial population could be reassessed by our study group. We found more subjects at T2 who had been rated as intelligent at T1. More subjects responding to T2 belonged to a higher social class, were more anxious, and had more psychosocial problems at T1. Social income at T2 is correlated to the social class at T1. More subjects have died since who were rated at T1 as being less intelligent, less neurotical, and having higher psychosocial problems. Twice as many men died than women. The emotional situation at T2 is significantly correlated to psychological well-being at T1. The somatic complaints at T2 correlate significantly to neurotic symptoms in childhood (T1). The more intelligent the children were rated at T1, the less emotional and somatic complaints were voiced at T2 and the better the psychic well-being was rated (T2). In addition, the former social milieu (T1) significantly determined somatic and psychological complaints at T2. Our data discern a significant correlation between actual status and former childhood variables more than 50 years later in a rural Swiss cohort (Emmental Cohort).

Vaccination with irradiated autologous melanoma cells engineered to secrete human granulocyte-macrophage colony-stimulating factor generates potent antitumor immunity in patients with metastatic melanoma.

We conducted a Phase I clinical trial investigating the biologic activity of vaccination with irradiated autologous melanoma cells engineered to secrete human granulocyte-macrophage colony-stimulating factor in patients with metastatic melanoma. Immunization sites were intensely infiltrated with T lymphocytes, dendritic cells, macrophages, and eosinophils in all 21 evaluable patients. Although metastatic lesions resected before vaccination were minimally infiltrated with cells of the immune system in all patients, metastatic lesions resected after vaccination were densely infiltrated with T lymphocytes and plasma cells and showed extensive tumor destruction (at least 80%), fibrosis, and edema in 11 of 16 patients examined. Antimelanoma cytotoxic T cell and antibody responses were associated with tumor destruction. These results demonstrate that vaccination with irradiated autologous melanoma cells engineered to secrete granulocyte-macrophage colony-stimulating factor stimulates potent antitumor immunity in humans with metastatic melanoma.

Characteristics of regions suspicious for pulmonary nodules at chest radiography.

RATIONALE AND OBJECTIVES: This study was performed to determine physical characteristics of areas on chest radiographs that are suspicious but not definitive for the presence of a pulmonary nodule and the characteristics of areas that contain an obvious nodule. MATERIALS AND METHODS: Two groups of patients were identified: those who had an area at plain radiography that was suspicious for a pulmonary nodule and underwent fluoroscopy for further evaluation (138 patients, 142 areas) and those who had an obvious nodule at plain radiography who underwent computed tomography for further evaluation (72 patients, 97 areas). The measured characteristics of the region of interest included size, circularity, compactness, contrast, and location. RESULTS: A comparison of the data show that while there was some difference between these groups of patients with regard to location of the nodules, there were essentially no differences with regard to size, circularity, compactness, and contrast of the regions of interest. CONCLUSION: Size, circularity, compactness, contrast, and location are not sufficient to distinguish pulmonary nodules from other suspicious regions on the chest radiograph.

Defining the superior border of posterior fossa radiation treatment fields.

PURPOSE: Lateral posterior fossa treatment fields are usually defined on traditional simulation films based on bony landmarks. The superior field border, intended to include the apex of the tentorium cerebelli, is frequently difficult to define. While sagittal magnetic resonance imaging (MRI) images or three-dimensional treatment planning tools are good means to locate the tentorial apex, these are not always available. We herein describe a method for locating the tentorial apex based on bony landmarks. METHODS AND MATERIALS: Midsagittal magnetic resonance images of 53 patients were reviewed. Using a Cartesian grid, the geometric relationship between the tentorial apex and several bony landmarks was assessed. Two lines were defined: the first connected the posterior clinoid and the internal occipital protuberance (AB). The second was perpendicular to the first, included the tentorial apex, and extended from the base of the skull inferiorly to the "crown" of the skull superiorly (DE). Relationships between measurements were made using linear regression and least square fits. RESULTS: Line DE was within 5 mm of the perpendicular bisector of line AB in 83% (44/53) of patients. The tentorial apex was located within 10 mm of the midpoint of DE in 91% (48/53) of patients. CONCLUSION: In the majority of patients, the location of the tentorial apex can be estimated based on bony landmarks, to within approximately 10 mm. The technique described is a useful means of estimating the location of the tentorial apex in patients where sagittal MRI imaging or three-dimensional treatment planning tools are not available.

The adrenergic inhibitors.

Although most of the centrally and peripherally-acting adrenergic inhibitors have been available for several years, they continue to contribute importantly to antihypertensive therapy. There are remarkably few contraindications to their use. They are useful in hypertension of all grades of severity, and are also valuable in complicated forms of hypertension, such as those associated with renal insufficiency, diabetes mellitus, and chronic obstructive lung disease. They can produce some fairly predictable side effects in patients, but generally do not cause significant metabolic changes. These drugs also seem to be tolerated well by physically active patients. They appear to have desirable effects on cardiac structure. In general, the adrenergic inhibitors cause regression of a left ventricular hypertrophy, which may well be a valuable property, especially in older hypertensive patients.

Doppler echocardiographic assessment of left ventricular systolic and diastolic function in mild hypertension.

Abnormalities in left ventricular (LV) wall thickness and mass have been demonstrated in patients with mild hypertension utilizing M-mode echocardiography. In addition, studies using radionuclide angiography have demonstrated abnormalities in early diastolic LV filling in asymptomatic hypertensive patients with normal ejection fraction and cardiac output. Recently, Doppler recordings of flow velocity in the ascending aorta and through the mitral valve have been shown to provide useful information about LV function. To determine whether flow abnormalities could be detected in patients with mild hypertension, we recorded Doppler aortic and mitral valve flow velocities in 21 men with mild hypertension. Casual systolic blood pressure was 147 +/- 18 mm Hg (mean +/- SD) and diastolic blood pressure was 96 +/- 9 mm Hg. LV mass (310 +/- 75 g) was elevated (i.e., above the 95% normal prediction interval) in 8 of 19 patients who underwent M-mode echocardiography; LV ejection fraction was normal in all patients (mean, 80%). As in previous studies in normal subjects, we found in these hypertensive patients an inverse correlation between age and both aortic peak flow velocity (r = -0.51, p less than 0.05) and transmitral early diastolic peak flow velocity (r = -0.44, p less than 0.05) and a positive relationship between age and mitral valve late diastolic peak flow velocity (r = 0.73, p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Disparate relationships between blood pressure and left ventricular mass in patients with and without left ventricular hypertrophy.

The relationship between casual blood pressure and left ventricular (LV) mass has been reported to be fairly weak in hypertensive patients. In this study we analyzed this relationship using noninvasive devices to monitor blood pressure for 24 hours in ambulatory patients and M-mode echocardiography to determine LV mass. Among the 33 patients with hypertension, 21 had echocardiographic LV hypertrophy (LV mass greater than 250 g). Patients with LV hypertrophy did not differ significantly from patients without hypertrophy with respect to age or casual systolic or diastolic blood pressure. The averages of whole-day systolic and diastolic blood pressures were 146 +/- 17 (SD) over 90 +/- 12 and 136 +/- 16 over 89 +/- 12 mm Hg, respectively. The relationship between whole-day average systolic blood pressure and LV mass was significantly positive (r = 0.66, p less than 0.05) in patients without hypertrophy but was not significant in patients with LV hypertrophy (r = -0.24). Similarly, the relationship between whole-day average diastolic blood pressure and LV mass was significantly positive in the former group (r = 0.64, p less than 0.05) but significantly negative in hypertensive patients with LV hypertrophy (r = -0.67, p less than 0.01). Thus, blood pressure correlates positively with LV mass only in patients without cardiac hypertrophy. In hypertensive patients with LV hypertrophy, factors additional to the high blood pressure itself must participate in the regulation of LV mass.

The antihypertensive effect of lisinopril compared to atenolol in patients with mild to moderate hypertension.

In a multicenter, parallel, double-blind study, lisinopril was compared with atenolol in the treatment of mild to moderate essential hypertension. Four hundred ninety patients were randomized to a once-a-day treatment with lisinopril 20 mg or atenolol 50 mg for 4 weeks, and the doses of lisinopril or atenolol were increased up to 80 mg or 200 mg, respectively, at 4-week intervals if sitting diastolic blood pressure (SDBP) was not well controlled. Hydrochlorothiazide (HCTZ) 12.5 or 25 mg was added after 12 weeks, if necessary, and titrated upward after 4 weeks to a maximum dose of 25 or 50 mg/day. Lisinopril and atenolol reduced SDBP to a similar extent. All reductions from baseline in sitting diastolic and systolic blood pressure were significant (less than 0.01). Lisinopril produced a significant (less than 0.01) greater reduction in sitting systolic blood pressure (SSBP) than atenolol. Addition of HCTZ caused further blood pressure reductions (p less than 0.01). Five patients (1.7%) on lisinopril and four (2.0%) on atenolol developed skin rashes during weeks 1-12. Two patients (0.7%) on lisinopril 80 mg developed proteinuria (greater than 1 g/day). Cough occurred more often with lisinopril (4.5%), and elevated triglycerides occurred more often with atenolol (2.0%).

Effect of the calcium channel blocker nitrendipine on left ventricular mass in patients with hypertension.

Reductions in left ventricular (LV) mass have been reported after antihypertensive therapy with certain sympatholytic agents and converting enzyme inhibitors, but little or no improvement has been noted after vasodilator therapy. In this study we evaluated the effect of the calcium channel blocker nitrendipine on echocardiographic LV mass. During a 12-month period, nitrendipine was used as monotherapy in 30 patients and in combination with propranolol or a diuretic in an additional 28 patients. Nitrendipine monotherapy lowered supine blood pressure from 148/97 to 136/83 mm Hg, but LV mass did not change significantly. Supine blood pressure decreased from 155/103 to 134/86 mm Hg in patients receiving combination therapy but, again, changes in LV mass were not significant. These data suggest that nitrendipine is effective in lowering blood pressure, but this is not associated with a significant decrease in LV mass in patients with mild hypertension.