Clathrin plays a novel role in the regulation of cell polarity, pseudopod formation, uropod stability and motility in Dictyostelium

Although the traditional role of clathrin has been in vesicle trafficking and the internalization of receptors, a novel role in cytokinesis was recently revealed in an analysis of a clathrin-minus Dictyostelium mutant (chc(-)). chc(-) cells grown in suspension were demonstrated to be defective in assembling myosin II into a normal contractile ring. To test whether this defect reflected a more general one of cytoskeletal dysfunction, chc(-) cells were analyzed for cell polarity, pseudopod formation, uropod stability, cell locomotion, chemotaxis, cytoskeletal organization and vesicle movement. chc(-) cells crawled, chemotaxed, localized F-actin in pseudopods, organized their microtubule cytoskeleton in a relatively normal fashion and exhibited normal vesicle dynamics. Although chc(-) cells extended pseudopods from the anterior half of the cell with the same frequency as normal chc(+) cells, they extended pseudopods at twice the normal frequency from the posterior half of the cell. The uropods of chc(-) cells also exhibited spatial instability. These defects resulted in an increase in roundness, a reduction in polarity, a reduction in velocity, a dramatic increase in turning, a high frequency of 180 degrees direction reversals and a decrease in the efficiency of chemotaxis. All defects were reversed in a rescued strain. These results are the first to suggest a novel role for clathrin in cell polarity, pseudopod formation, uropod stability and locomotion. It is hypothesized that clathrin functions to suppress pseudopod formation and to stabilize the uropod in the posterior half of a crawling cell, two behavioral characteristics that are essential for the maintenance of cellular polarity, efficient locomotion and efficient chemotaxis.

Measurements of multiply scattered light for on-line monitoring of changes in size distribution of cell debris suspension

Dual wavelength frequency-domain measurements of photon migration (FDPM) are conducted on filtrate samples obtained from an industrial centrifugation process designed to separate Escherichia coli cell debris from the inclusion bodies. FDPM measurements consist of detecting phase delay of intensity-modulated light at 670 and 820 (or 830) nm. Optical properties of isotropic scattering and absorption are obtained from the regression of phase delay data to the optical diffusion equation. We show that the corresponding intensity-based measurements alone cannot provide accurate and independent estimates for these optical properties. However, FDPM-derived scattering coefficients of filtrate solutions (primarily consisting of 0.1-0.2 micrometer E. coli cell debris) are sensitive to approximately 1 vol % of added inclusion bodies (of 1-2 micrometer size). The technique, theory, and future adaptation of FDPM as an on-line monitor to detect the loss of inclusion bodies in centrifugation following homogenization are presented and contrasted to conventional, intensity-based measurements.

Increased carriage of resistant non-pneumococcal alpha-hemolytic streptococci after antibiotic therapy

OBJECTIVE

We compared colonization and resistance rates of non-pneumococcal alpha-hemolytic streptococci (AHS) and Streptococcus pneumoniae in children receiving antibiotic therapy for acute otitis media.

STUDY DESIGN

Between December 1997 and September 1998, children 6 months to 6 years of age, diagnosed with acute otitis media were randomly assigned to receive amoxicillin/clavulanate (Augmentin) 45 mg/kg/d in 2 divided doses for 10 days or azithromycin (Zithromax), 10 mg/kg, once on the first day, followed by 5 mg/kg daily for 4 days. Nasopharyngeal swabs for culture were obtained before and at 2 weeks and 2 months after the start of therapy. Streptococci were identified by species, and antibiotic susceptibility was determined by the epsilometric test.

RESULTS

One hundred six children completed the 2-week follow-up and 2-month follow-up, respectively. The nasopharyngeal carriage rate of non-pneumococcal AHS increased from 14% before treatment to 32% at the 2-week follow-up (P =.02) and was similar in both treatment groups. In contrast, the carriage of S pneumoniae decreased from 51% before therapy to 27% at the 2-week follow-up (P =.002). The carriage of penicillin-resistant AHS strains (minimum inhibitory concentration > 1 microg/mL) increased from 9% before treatment to 26% at 2 weeks and 36% at 2 months.

CONCLUSIONS

Amoxicillin/clavulanate and azithromycin therapy resulted in increased isolation of nasopharyngeal non-pneumococcal AHS, many of which were multidrug-resistant, in contrast to a decrease in pneumococcal carriage. This suggests that the competitive balance between these 2 groups of organisms was disturbed as a result of differential antibiotic susceptibility. The importance of drug-resistant AHS as a reservoir for resistance genes for S pneumoniae warrants further investigation.

Anterior discectomy and fusion for the management of neck pain

STUDY DESIGN

Data were collected prospectively on 38 patients who underwent anterior cervical discectomy and fusion for neck pain with no symptoms or signs of radiculopathy or myelopathy.

OBJECTIVES

To determine the changes in pain and function after anterior cervical discectomy and fusion for nonradicular neck pain.

SUMMARY OF BACKGROUND DATA

There is considerable controversy regarding the role of anterior cervical discectomy and fusion for neck pain in the absence of radiculopathy or myelopathy. Although no studies have addressed this specific and common problem, it is known that anterior cervical discectomy and fusion for radiculopathy or myelopathy may also provide relief of neck pain for many patients.

METHODS

Thirty-eight patients who underwent anterior cervical discectomy and fusion for neck pain were evaluated. Before and after surgery, the authors measured pain with a numerical rating scale, function with the Oswestry Disability Questionnaire, and final patient satisfaction. Final evaluation was done by a disinterested third party.

RESULTS

All 38 patients were available for follow-up study. Mean age was 42.4 years, and mean duration of follow-up study was 53 months. All patients had painful disc(s) proven by discography. No patients had nerve root compression. Anterior cervical discectomy and fusion was performed at one level in 21 patients, two levels in 16 patients, and three levels in one patient. The mean score on the numerical rating scale for neck pain before surgery was 8.3 (range, 3-10) versus 4.1 (range, 0-10) after surgery. This difference is significant (P < 0.001). The mean score on the Oswestry Disability Questionnaire was 57.5 (range, 0-89) before surgery versus 38.9 (range, 0-80) after surgery. This difference is significant (P < 0.001). There were 30 (79%) patients who were satisfied with their outcome, and 8 (21%) who were not satisfied. There was no statistical difference in change of pain or function between patients with worker's compensation and those with other insurance or between men and women. Twenty patients were not working because of neck pain before surgery, and 15 were not working at the time of follow-up examination.

CONCLUSION

A significant decrease in pain, a significant increase in function, and a high degree of patient satisfaction were found with anterior cervical discectomy and fusion for neck pain. Improvements were not affected by worker's compensation status or gender.

The applicability of selected rational-emotive therapy principles for pastoral counseling

Examines the compatibility and possibility of communication between pastoral counseling and Rational-Emotive Therapy (RET). Uses a Delphi technique to determine whether a randomly selected group of pastoral counselors (N = 15) believe that the basic principles of RET can be used without surrendering theological tenets foundational to pastoral counseling. Concludes that some RET principles may be applicable for pastoral counseling.

Investigation of static structure factor in dense suspensions by use of multiply scattered light

Near-infrared, frequency-domain photon migration measurements of phase shift are used to derive accurate values of isotropic scattering coefficients in concentrated, interacting suspensions of aqueous polystyrene microspheres with volume concentrations ranging from 1% to 45% by solids and mean diameters ranging from 135 to 500 nm. Under conditions of high ionic strength, the isotropic scattering coefficient can be quantitatively predicted by the Percus-Yevick model for hard-sphere interactions and Mie theory. In addition, the attractive interactions between scatterers arising from the addition of soluble poly(ethylene glycol) with molecular weights of 100 and 600 K cause hindered scattering. The increases in static structure and decreases in isotropic scattering coefficient agree with that predicted by Mie theory and the depletion interaction model developed by Asakura and Oosawa [J. Chem. Phys. 22, 1255 (1954)]. These results demonstrate the success of monitoring interaction between particles by use of multiple-scattered light and the necessity of incorporating models for these interactions when predicting scattering of dense, concentrated suspensions.

Etiology of genital ulcers and prevalence of human immunodeficiency virus coinfection in 10 US cities. The Genital Ulcer Disease Surveillance Group

To determine the etiology of genital ulcers and to assess the prevalence of human immunodeficiency virus (HIV) infection in ulcer patients in 10 US cities, ulcer and serum specimens were collected from approximately 50 ulcer patients at a sexually transmitted disease clinic in each city. Ulcer specimens were tested using a multiplex polymerase chain reaction assay to detect Haemophilus ducreyi, Treponema pallidum, and herpes simplex virus (HSV); sera were tested for antibody to HIV. H. ducreyi was detected in ulcer specimens from patients in Memphis (20% of specimens) and Chicago (12%). T. pallidum was detected in ulcer specimens from every city except Los Angeles (median, 9% of specimens; range, 0%-46%). HSV was detected in >/=50% of specimens from all cities except Memphis (42%). HIV seroprevalence in ulcer patients was 6% (range by city, 0%-18%). These data suggest that chancroid is prevalent in some US cities and that persons with genital ulcers should be a focus of HIV prevention activities.

Randomised controlled trial of effects of early discharge after surgery for breast cancer

OBJECTIVE

To determine the effect of early discharge from hospital after surgery for breast cancer on physical and psychological illness.

DESIGN

Randomised controlled trial comparing discharge two days after surgery (before removal of drain) with standard management (discharge after removal of drain).

SETTING

Regional breast unit.

SUBJECTS

100 women with early breast cancer undergoing mastectomy and axillary node clearance (20) or breast conservation surgery (80).

MAIN OUTCOME MEASURES

Physical illness (infection, seroma formation, shoulder movement) and psychological illness (checklist of concerns, Rotterdam symptom questionnaire, hospital anxiety and depression scale) preoperatively and at one month and three months postoperatively.

RESULTS

Women discharged early had greater shoulder movement (odds ratio 0.28 (95% confidence interval 0.08 to 0.95); P = 0.042) and less wound pain (odds ratio 0.28 (0.10 to 0.79); P = 0.016) three months after surgery compared with women given standard management. One month after surgery scores were significantly lower on the Rotterdam symptom questionnaire in patients who were discharged early (ratio of geometric mean scores 0.73 (0.55 to 0.98) P = 0.035), but rates of psychological illness generally did not differ between groups.

CONCLUSIONS

Increased rates of physical or psychological illness did not result from early discharge after surgery for breast cancer. This policy can be recommended for patients with support at home.

A family-based analysis of whether the functional promoter alleles of the serotonin transporter gene HTT affect the risk for alcohol dependence

A population association between a regulatory variation in the promoter of the serotonin transporter gene (HTT) and severe alcohol dependence was recently reported. We analyzed this potential association in a large number of systematically ascertained families in the United States; these families had at least three first-degree relatives who were alcohol-dependent. Analyses focused on individuals defined as alcohol-dependent by criteria from ICD-10 and on subsets of these individuals reporting withdrawal-related symptoms. Application of the transmission disequilibrium test did not provide support for either linkage or association between this functional polymorphism and alcohol dependence; there was no significant bias in the transmission of either allele to the alcohol-dependent offspring. We also report that African Americans differ from Caucasians in allele frequencies for this polymorphism.

Take Five, a nutrition education intervention to increase fruit and vegetable intakes: impact on attitudes towards dietary change

To assess the response of low consumers of fruit and vegetables to a nutrition education intervention programme, data were collected from 104 adults on attitudinal variables related to 'eating more fruit, vegetables and vegetable dishes'. Questionnaires (based on the theory of planned behaviour) assessing perceived barriers to increasing fruit and vegetable consumption were administered before an action-orientated intervention programme and at the end of the intervention period (8 weeks). Questionnaire scores for belief-evaluations in the intervention groups pre- and post-study indicated that support of family and friends, food costs, time constraints and shopping practicalities (in order to increase intake of fruit, vegetable and vegetable dishes) were barriers to greater consumption of these foodstuffs. Perceived situational barriers to increasing intakes of fruits and vegetables were: limited availability of vegetables, salads and fruit at work canteens, take-aways, friends' houses and at work generally. Following the intervention the number of visits to the shops was perceived as a greater barrier for increasing intakes of fruit and vegetables. Perceived practical opportunities for increasing intakes high-lighted drinking fruit juice, taking fruit as a dessert, having fruit as a between-meal snack and eating two portions of vegetables with a meal. About two-thirds of intervention subjects achieved the recommended fruit and vegetable target, but it is concluded that practical issues and situational barriers need to be addressed for the success of future public health campaigns.

Take Five, a nutrition education intervention to increase fruit and vegetable intakes: impact on consumer choice and nutrient intakes

This study reports results from a randomized controlled intervention trial, focusing on: (1) the identification of successful consumer strategies for increasing fruit and vegetable intakes to the recommended levels of more than five (80 g) portions per day and (2) impact on overall diet and nutrient intakes. Adult men and women (n 170) fulfilling the main recruitment criterion of eating less than five fruit and vegetable portions per day but contemplating increasing intakes were recruited. Complete valid dietary data was provided by 101 intervention (fifty-nine estimated fruit and vegetable intakes, and forty-two simultaneous weighted total dietary and estimated fruit and vegetable intakes) and twenty-four control subjects (weighed total dietary intakes). Intervention advice included the specific association of high fruit and vegetable intake with reduced risk of disease, practicalities, and portion definition with a target intake of greater than five 80 g fruit and vegetable portions per day for 8 weeks. There were significant effects (P < 0.001) on weighed intakes of fruit and vegetables in the intervention group, rising from 324 (SE 25) to 557 (SE 31) g/d and reflected by validated portion measures at 8 weeks intervention. Successful strategies chosen by 'achievers' of the target intake (65% of subjects) were conventional (fruit as a snack, vegetables with main meals etc.) and favoured fruit. There were significant increases in percentage energy from carbohydrate (from sugars not starch), vitamin C, carotenes and NSP and there was a significant decrease in percentage energy from fat for subjects who had high fat intakes (> 35% energy) at baseline. Follow-up self-reported measures at 6 and 12 months indicated mean intakes of 4.5 and 4.6 defined portions/d respectively, suggesting some sustainable effect. In conclusion, the intervention led to significant increases in fruit and vegetable intakes largely via conventional eating habits, with some desirable effects on macro- and micronutrient intakes.

Dissolution of multicomponent microbubbles in the bloodstream: 2. Experiment

The effect of the nature of the filling gas on the persistence of microbubbles in the bloodstream was studied. All the microbubbles were covered with the same shells. Various perfluorocarbons and perfluoropolyethers alone and as mixtures with nitrogen were used as the filling gases. The persistence time of microbubbles in the bloodstream tau increased with the molecular weight of the filling gas, from approximately 2 min for perfluorethane, to > 40 min for perfluorodiglyme, C6F14O3, and then decreased again to 8 min for C6F14O5. An acceptable ultrasound scattering efficacy was exhibited by the filling gases with intermediate molecular weights that possessed both a high saturated vapor pressure and a comparatively low water solubility (Ostwald coefficient). On the basis of the experimental data, it is concluded that the microbubble persistence tau is controlled primarily by the dissolution of microbubbles and not by the removal of the microbubbles by the reticular endothelial system. Although the qualitative experimental trends are in good agreement with the theoretical model developed previously, there are some quantitative differences. Possible reasons for these differences are discussed.

Organizing health care for people with seizures and epilepsy

The day-to-day responsibilities of managing seizures and epilepsy fall most heavily on patients and their families. Unfortunately, health care services in the United States are not organized to identify, diagnose, and treat people with seizures effectively nor are they delivered in such a way that patients and their families can engage in a positive, collaborative relationship with health care providers. This article describes a model of chronic illness care as applied to seizures and epilepsy, that is, how care should be structured to help people with seizures live as well as possible.

Diurnal patterns of CO2 and H2O exchange of the Arctic sedges Eriophorum angustifolium and E. vaginatum (Cyperaceae)

Eriophorum vaginatum and E. angustifolium are dominant arctic sedges of the well-drained tussock tundra and the permanently flooded wet-sedge tundra, respectively. We determined diurnal courses of gas exchange and water relations of the two species in their natural habitat and compared their responses to changes in light, air temperature, and humidity. Mean photosynthetic response to light was similar between E. angustifolium and E. vaginatum and carbon gain in both species was light limited during most of the growing season. On sunny and dry days, both species closed stomata in response to high leaf-to-air vapor pressure deficits. Even though E. angustifolium was growing in standing water, it exhibited a tighter control of transpirational water loss and had lower hydraulic conductivity in the soil-root-shoot pathway than E. vaginatum. The different response pattern between the two species is discussed in the context of differences in habitat conditions.