Simplified organ cultures of human embryo trachea in the diagnosis of viral respiratory disease of children.

Organ cultures of human embryonic trachea in test tubes were used as an adjunct to tissue cultures in the isolation of respiratory viruses from children in hospital. Fifty-one viruses were obtained from 127 specimens, giving an isolation rate of 40%. Fifteen viruses were isolated from the original tissue cultures and also after passage through organ culture. Thirty viruses were isolated from the original tissue culture only, and six viruses only from organ culture (three para-influenza, one influenza A, and one rhinovirus). An increase of 5% in virus isolation rate over that of standard tissue culture was obtained.

Liquid chromatographic determination of urea in water-soluble urea-formaldehyde fertilizer products and in aqueous urea solutions: collaborative study.

Water soluble urea-formaldehyde (UF) fertilizers, manufactured by complex reaction of urea and formaldehyde, typically contain varying amounts of unreacted urea. A liquid chromatography method for the analysis of urea in these products, and in aqueous urea solutions, was collaboratively studied. An amine chromatography column was used to separate the unreacted urea from numerous UF reaction products present in these liquid fertilizers. Unreacted urea was determined by using external urea standards with UV detection at 195 nm. The standards and test samples were prepared in the mobile phase of 85% (v/v) acetonitrile in water. Ten laboratories analyzed 5 different UF-based commercial products containing unreacted urea in the range of 6 to 17% by weight, and 5 different concentrations of urea in water equivalent to commercial products of that nature. The aqueous urea solutions contained 2-20% urea (w/w). The range of s(R) values for the 5 UF-based commercial fertilizers was 0.49-1.02 and the %RSD(R) was 1.94-6.14. The s(R) range for the 5 urea solutions was 0.10 to 0.79 and the %RSD(R) range was 2.54 to 4.88. The average recovery of urea from the aqueous urea solutions was 96-103%. Therefore, this method is capable of monitoring urea nitrogen manufacturers' label claims and total nitrogen claims in those cases where urea is the sole source of plant food nitrogen. Based on the collaborative study data, the authors recommend this method be approved for AOAC Official First Action status.

Nasal and cloacal bacteria in free-ranging desert tortoises from the western United States.

Aerobic bacteria were collected from three free-ranging desert tortoise (Gopherus agassizii) populations in the eastern Mojave Desert (Arizona, Utah; USA) from 1989 to 1993, and from two free-ranging populations in the central Sonoran Desert (Arizona, USA) from 1990 to 1994. Six species of nasal bacteria and 18 species of cloacal bacteria were identified. At least one potential pathogen was found in the nasal cavity (Pasteurella testudinis), and at least two potential pathogens in the cloaca (Pseudomonas spp., Salmonella spp.).

The thermal effects of shortening in tetanic contractions of frog muscle.

1. In tetanic contractions during which shortening has occurred the total heat produced is greater than in isometric controls.2. The amount of this excess, measured after relaxation, is less than the shortening heat measured before relaxation. In other words relaxation heat is less after contractions with shortening.3. Only a small part of this reduction in relaxation heat can be explained by the reduced thermoelastic heat and work dissipation due to the lower tension maintained after shortening.4. In the few experiments in which the full tension is redeveloped after shortening the relaxation heat is still reduced.5. Decreases in the tension redeveloped after shortening, caused by using shorter tetani, or slower shortening, are not accompanied by decreases in the relaxation heat greater than can be accounted for by the assumed physical results of the lower tension.6. It is suggested that the reduction in relaxation heat after shortening is due to the occurrence of a reaction in which the exothermic process causing the shortening heat is reversed.

Supplement use, other dietary and demographic variables, and serum vitamin C in NHANES II.

OBJECTIVE: Our objective was to evaluate the effect of regular use of nutritional supplements on serum vitamin C levels in a multivariable regression model, taking into account other dietary and demographic variables which may affect nutritional status. METHODS: We analyzed NHANES II data for subjects age 3 to 74. Analysis was limited to regular supplement users and nonusers, excluding irregular users. Multivariable regression analysis was performed with SUDAAN, incorporating sample weights and accounting for the complex survey design. RESULTS: Regular supplement users had substantially higher serum vitamin C levels than nonusers (p < 0.001). The magnitude of the effect of supplement use on serum vitamin C was 0.23-0.33 mg/dL in children and teens, and 0.36-0.46 mg/dL in adults. In adults who smoked, bottom quartile vitamin C levels were 0.3 mg/dL in men and 0.4 mg/dL in women who did not use supplements, compared to 0.9 and 1.1 mg/dL in regular supplement users. There was a significant interaction of smoking and supplement use in men (p < 0.001). CONCLUSION: Regular supplement use has a strong impact on serum vitamin C levels, independent of other dietary and demographic characteristics of supplement users which may favor improved nutritional status.

The product of maize streak virus ORF V1 is associated with secondary plasmodesmata and is first detected with the onset of viral lesions.

We have used a polyclonal antiserum derived from a bacterially expressed viral fusion protein to investigate the expression and subcellular localisation of the maize streak virus V1 product (PV1). Western blot analysis of agroinfected tissue showed that PV1 was detectable from 10 days postinoculation, coinciding with the first appearance of chlorotic viral lesions. The viral protein was only detectable in cell wall fractions of plant protein extracts. PV1 migrated with an apparent size of 14 kDa on SDS-PAGE, larger than the 10.9 kDa predicted from the amino acid sequence and therefore suggestive of posttranslational modification. Immunogold labelling located PV1 to the cell walls within lesion tissue and demonstrated a close association between the viral protein and secondary plasmodesmata. These results are consistent with the V1 product of MSV playing a role in the cell-to-cell movement of the virus in infected plants.

Down's syndrome with a recombinant tandem duplication of chromosome 21 derived from a maternal ring.

An account is given of the cytogenetic investigations of a girl with Down's syndrome found to have a dicentric duplication of chromosome 21. This tandem type of rearrangement was interpreted as a recombinant derived from a single meiotic crossover between a maternal ring 21 and its normal homologue. A population of cells was also found in which breakage of the dicentric resulted in a chromosome 21 with a small terminal deletion. The mother and the proband's younger brother, who was also a ring 21 heterozygote, were both clinically normal.

Language production and comprehension in an adult with ACoA syndrome.

This study explored the prediction that cases with anterior communicating artery (ACoA) syndrome will exhibit deficits in higher-level language production and comprehension. A 65-year-old adult male with a history of ACoA syndrome was tested on higher-level linguistic tasks. The patient's performance on discourse comprehension. discourse production, and linguistic ambiguity comprehension tasks was impaired.

Significance of chromosome 22q11 analysis after detection of an increased first-trimester nuchal translucency.

OBJECTIVE: To determine the value of performing routine fluorescent in situ hybridization (FISH) for microdeletions of chromosome 22q11 when karyotyping fetuses with increased nuchal translucency. DESIGN: This was a prospective observational study carried out over an 18-month period. Fetal karyotyping by chorionic villus sampling was offered to 5429 women attending for a routine booking scan in the first trimester when their nuchal translucency adjusted risk for Down syndrome was > or = 1 in 300. Cytogenetic samples were routinely tested for the 22q11 microdeletion when the nuchal translucency was > or = 3 mm. RESULTS: The prevalence of increased nuchal translucency > or = 2.5 mm was 180 (3.3%) and > or = 3.5 mm was 42 (0.8%). None of 75 fetuses with an increased nuchal translucency and normal karyotype demonstrated a 22q11 microdeletion on FISH analysis. In the same cohort, 3 of 20 (15%) cases of major congenital heart defects in which nuchal translucency was measured, had a nuchal translucency measurement > or = 2.5 mm. CONCLUSIONS: Routine FISH analysis for chromosome 22q11 microdeletions at the time of chorionic villus sampling for increased first-trimester nuchal translucency is of limited value. As a significant proportion of fetuses with increased nuchal translucency will be found to have congenital heart defects later in the pregnancy, FISH analysis for chromosome 22q11 microdeletions can be targeted to fetuses with specific congenital heart defects. Tissue from the chorionic villus sampling should therefore be stored for subsequent analysis, until after detailed echocardiography is performed.

The prevalence of antibodies to Rickettsia rickettsii in an area endemic for Rocky Mountain spotted fever.

A study of Rickettsia rickettsii was conducted in Rowan, Cabarrus, and Granville counties, North Carolina in an attempt to define the prevalence of endemic infection in this area. Serum samples were obtained from 1,976 healthy persons and tested by indirect hemagglutination for detectable antibodies to R. rickettsii. Of this group, 568 (28.7%) had detectable antibody (greater than or equal to 1:8), 80 (4%) had titers greater than or equal to 1:64, and 1,408 (70%) had no detectable antibody (less than or equal 1:8). Indirect immunofluorescence testing for antibody was also performed for 315 (15%) of the serum samples, of which 301 (95%) had undetectable titers and 14 (5%) had detectable titers ranging from 1:8 to greater than or equal to 1:64. Serological reactivity by indirect hemagglutination was detected in persons in the absence of known Rocky Mountain spotted fever. The study failed to show a good correlation of either the height of the geometric mean titer or percentage of seropositive persons with the previously determined age-related rates of acquisition of the disease. These data suggest that the antibodies measured may not be specific for R. rickettsii or that the antibody levels wane with time or both. It is probable that unrecognized infection occurs, but the true incidence or prevalence cannot be determined by available serological tests.

Epidemiology of Rocky Mountain spotted fever as determined by active surveillance.

Prospective, active surveillance for Rocky Mountain Spotted fever (RMSF) was undertaken in two North Carolina counties for the years 1979-1981. Appropriate age, sex, and geographically matched controls were compared with the serologically confirmed cases of disease. Patients who were suspected of having infection, but were shown not to have RMSF, were also compared with the serologically proven cases. Ninety-eight cases were identified, and three of these patients died. The mean annual incidence of RMSF in these two counties was 14.59 cases/100,000 population. Identified cases occurred between the months of March and September. The overall mean annual incidence for men was 19.65/100,000 and for women 10.3/100,000. The study suggests that persons contracting RMSF are exposed to the vectors at their residences, which tend to be detached dwellings in woody, brushy areas. Children are more likely than adults both to be seen by physicians early in the illness and to be checked for ticks. Eighty-four percent of patients with serologically confirmed cases developed a rash. The epidemiology of RMSF in these two endemic counties is described.