C. elegans avoids toxin-producing Streptomyces using a seven transmembrane domain chemosensory receptor

Predators and prey co-evolve, each maximizing their own fitness, but the effects of predator–prey interactions on cellular and molecular machinery are poorly understood. Here, we study this process using the predator Caenorhabditis elegans and the bacterial prey Streptomyces, which have evolved a powerful defense: the production of nematicides. We demonstrate that upon exposure to Streptomyces at their head or tail, nematodes display an escape response that is mediated by bacterially produced cues. Avoidance requires a predicted G-protein-coupled receptor, SRB-6, which is expressed in five types of amphid and phasmid chemosensory neurons. We establish that species of Streptomyces secrete dodecanoic acid, which is sensed by SRB-6. This behavioral adaptation represents an important strategy for the nematode, which utilizes specialized sensory organs and a chemoreceptor that is tuned to recognize the bacteria. These findings provide a window into the molecules and organs used in the coevolutionary arms race between predator and potential prey.

A robotic manipulator for handling TLD badges

A prototype system for automatic handling of Harshaw/Bicron (now ThermoFisher Scientific) thermoluminescent dosimetry (TLD) badges, which is based on a robotic arm, was designed and built. The robot performs the loading and unloading of the TLD cards in the badges and transports them between the loading/unloading station and magazine stations. For quality assurance, a sticker containing the worker's details printed in barcode format was added to the badge. Automatic on-line identification is performed for checking the correlation between the badge and the TLD card number.

Multifocal osteosarcoma in a patient with Fanconi anemia

PURPOSE

The purpose of this report is to present a case of multifocal osteosarcoma in a patient with Fanconi anemia.

PATIENTS AND METHODS

A nine year old girl with known Fanconi anemia presented with a pathologic femur fracture. Imaging studies confirmed soft tissue and bony involvement in the femur, ipsilateral tibia, and possibly contralateral femur.

RESULTS

Biopsy and subsequent amputation confirmed the presence of classic osteosarcoma in the involved femur and ipsilateral tibia. The patient died seven months later of pulmonary failure secondary to metastases.

CONCLUSION

Fanconi anemia is known to be associated with malignancies such as leukemias. We report a new association of Fanconi anemia with osteosarcoma.

Rifampin preventive therapy for tuberculosis in Boston's homeless

An epidemic of isoniazid (INH)- and streptomycin (SM)-resistant tuberculosis began among Boston's homeless population in 1984. Individuals with skin test conversions who agreed to preventive therapy received either INH, rifampin, or a combination of INH and rifampin. A total of 204 individuals with documented tuberculin skin test conversions who did not have active tuberculosis at the time of the clinical evaluation for their positive skin test were eligible for preventive therapy. Data on type and length of preventive therapy were obtained from the Tuberculosis Clinic and the Boston Tuberculosis Registry records at Boston City Hospital. The individuals were followed for development of active tuberculosis. Six of 71 (8.6%) individuals who received no therapy, 3 of 38 (7.9%) in the INH group, and none in the rifampin or rifampin plus INH groups (49 and 37 persons, respectively) developed active tuberculosis. Patients in the rifampin group were significantly less likely to develop tuberculosis than patients in the no therapy group (p = 0.04; odds ratio [OR] = 0.00, 95% confidence interval [CI] = 0.00-0.91). Treatment with any rifampin-containing preventive therapy (rifampin or rifampin plus INH) was effective (p < 0.01 ) in preventing development of active disease. The three INH failures were with organisms that were resistant to INH.

Comparisons of blood pressure between Asian-American children and children from other racial groups in Chicago

RESEARCHERS COMPARED AVERAGE BLOOD PRESSURE, prevalence of elevated blood pressure, and average anthropometric measurements of Asian children with those same measures in children from other racial and ethnic groups, including blacks, whites, and Hispanics. The sample consisted of 1318 boys and 1548 girls ages 6 to 9 who had complete blood pressure and anthropometric data, which were derived from a health screening program in nonpublic schools conducted by the Chicago Department of Health from 1975 to 1978. The systolic pressure, adjusted for age, weight, and height, for Asian, black, Hispanic, and white boys was 108.1, 105.8, 104.7, and 105.6 mmHg, and for diastolic pressure, the adjusted values were 59.6, 58.9, 56.3, and 57.4 mmHg. For both systolic and diastolic, the differences between Asian boys and white boys and between Asian boys and Hispanic boys were statistically significant. For girls, the results were similar. In addition, for boys, the prevalence rates of elevated blood pressure (systolic greater than or equal to 122 mmHg or diastolic greater than or equal to 78 mmHg) were similar among the four groups. For girls, the prevalence rate for Asians was higher than those in the other groups; however, the differences were not statistically significant. Since hypertension is a major health problem in Asians, it is important to confirm these findings and to understand why mean blood pressure adjusted for age and body size is higher in Asian children than in other racial groups.

Comparison of three weight-for-height indices in blood pressure studies in children

Associations between blood pressures and three indices commonly used to assess relative obesity (weight (kg)/height (m)2, weight (kg)/height (m)3, and weight (kg)/height (m)p) were examined in a multiracial sample of children attending private schools in Chicago, Illinois. The 1,723 boys and 1,878 girls were 5-10 years old at the time of the survey (1975-1978). Inclusion of white, black, Hispanic, and Asian children permitted comparison of the relation between anthropometric variables and blood pressures across racial groups. The three weight-for-height indices used as estimates of relative obesity yielded nearly identical regression models, suggesting that, in spite of ongoing debate about the most appropriate index for describing relative obesity in children, it makes little difference which index is used.

Ethnic differences in blood pressure and heart rate of Chicago school children

In 1975-1978, the Chicago Department of Health conducted a screening program that included measurements of blood pressure, heart rate, height, weight, triceps skinfold thickness, and arm circumference, and calculation of body mass index and muscle circumference for non-public school children. Based on data on 4,086 boys and girls aged 5-10 years from the program, this study examined the ethnic differences in blood pressure and heart rate among children of white, black, Latino, and Oriental ethnicity. Mean levels for both systolic and diastolic blood pressure were higher for Oriental and black children than for white and Latino children. These differences were independent of age, height, weight, and skinfold thickness. The black children had a much lower mean heart rate than the other children. A seasonal variation was observed for systolic blood pressure, i.e., with each sex group, the mean systolic blood pressure adjusted for age, skinfold thickness, and height tended to be higher in spring than in fall and winter. (Note-- no child was screened during the summer because of summer break.) With control for season, ethnic differences in systolic blood pressure disappeared, but not the ethnic differences in diastolic blood pressure and heart rate.

Comparison of intraluminal and intravenous mediators of colonic response to eating

Eating a 1000-kcal mixed meal stimulates an increase in distal colonic motility. Fat is the dietary component which is the major stimulant of colonic spike activity. In this study the colonic spike activity increased similarly after the mixed meal [19.1 +/- 2.4 spike potentials (SP)/30 min] and after the fat meal (19.4 +/- 5.4 SP/30 min). Fat stimulated a concentration-dependent increase in colonic motility only when in contact with the gastroduodenal mucosa. Intravenous administration of Liposyn (100 kcal/hr) did not stimulate an increase in colonic spike activity (3.3 +/- 1.3 SP/30 min) despite greater increase in plasma total fatty acid levels than after the oral ingestion of fat. In contrast both the oral ingestion and the intravenous administration of an amino acid mixture (Aminosyn) inhibited the gastrocolonic response after the 1000-kcal mixed meal. Thus, these studies demonstrate: (1) fat stimulates colonic motility only through direct mucosal contact, and (2) a mixture of amino acid inhibits colonic motility through either mucosal contact or by circulating in the plasma. The exact neurohumoral mechanisms involved in both of these effects is unknown at present.

A reexamination of the validity of the Children's Personality Questionnaire

Scores on the Children's Personality Questionnaire (CPO) were correlated with ratings on the Devereux Elementary School Behavior Rating Scale (DESB). Three judges matched scales from the two instruments that appeared to measure the same behavior. For about one-third of these matches significant correlations in the predicted direction were found. Of the 156 possible correlations between CPQ factors and DESB scales 50 reaches significance. The results contradict those of a similar investigation (Willis & Sevmour, 1978), whose methodology is questioned. The correlations found in the present study provide limited support for the validity of CPQ factors.

The association between urinary sodium excretion and blood pressure in children

This study explored the association between sodium excretion and blood pressure (BP). A new method was used to minimize the measurement error introduced by the large intrinsic variability of 24-hour sodium excretion. The ratio of intra- to interindividual variation was used to estimate the number of measurements needed to characterize the individual. When seven consecutive 24-hour samples were collected from 73 children, ages 11-14 years, a significant correlation between mean individual sodium excretion and BP was demonstrated. The independent relationship persisted when controlling for height, weight, pulse, age, sex and race (p = 0.045), but was eliminated by simultaneously considering mean creatinine excretion. Although the cross-sectional association described is quantitatively weak, a linear relationship between BP and sodium over the range consumed in this society could be important for prevention.

Aneurysm of a persistent sciatic artery

Angiographic examination in a patient with sciatic-like pain on the right side and a firm, pulsatile, non-tender mass in the right buttock revealed a large sciatic artery aneurysm. The aneurysm was successfully resected at surgery. The primitive sciatic artery is the main arterial supply to the lower extremities in the 9-mm embryo. Its persistence, while very rare, is of clinical significance because of the tendency for aneurysms to develop in the artery. Surgical resection is indicated in sciatic artery aneurysms because of the danger of rupture or embolic occlusion of arteries distal to the aneurysm.

Laryngeal spasm complicating pseudomyotonia

Pseudomyotonia is a syndrome characterized by progressive muscle stiffness, weakness, myokymia, hyperhydrosis, and wasting of muscle. It especially affects the distal aspect of the extremities. The electromyogram is characteristic, and shows continuous muscle activity at rest. We discuss a case that is believed to be the first recorded instance of pseudomyotonia complicated by airway obstruction secondary to laryngeal spasm. Treatment with phenytoin sodium resulted in rapid improvement of the peripheral symptoms and simultaneous resolution of the laryngeal spasm.

Enhancement of low spatial frequency signals with optical aperture tapering

Detection of weak signals in an optical spectrum analyzer is impaired by sidelobes from nearby large signal components in the output spectrum. Strong sidelobes about the zero frequency component particularly inhibit detection of low frequency signals. Sidelobe response can be attenuated by suitable illumination tapering over the input data aperture. Changes of first and second sidelobe levels and main lobe width have been investigated for gaussian, lorentzian, and exponential tapers. Improved capability to distinguish weak low frequency signals in the presence of distortions introduced by component flaws is demonstrated for the exponential form.