Limited magnitude and breadth in the HLA-A2-restricted CD8 T-Cell response to Nef in children with vertically acquired HIV-1 infection.

CD8 T cells are believed to play a key role in the immune control of human immunodeficiency virus-1 (HIV-1) infection in children as well as in adults. We have used an enhanced EliSpot (AmpliSpot) assay to quantitate CD8 T-cell responses directed to five human leucocyte antigen (HLA)-A2-presented HIV-1 epitopes derived from the key viral antigen Nef. Responses were assayed in one group of 21 children with vertically acquired HIV infection and one group of 19 adult subjects with chronic infection. The paediatric group displayed significantly weaker and more narrowly focused CD8 T-cell responses as compared with the adult subjects. Two epitopes stood out as the most frequently and strongly recognized, suggesting that they should be considered immunodominant in the CD8 T-cell response to HIV-1 Nef. Interestingly, the most frequently and strongly recognized epitope in both adults and children was previously identified in HLA-A2-transgenic mice, demonstrating the usefulness of such mice in finding natural viral epitopes. These findings indicate significant weakness in strength and breadth of the CD8 T-cell response to the target protein Nef in infected children and prompt renewed efforts into the immunology of vertically acquired HIV-1 infection.

Sarcomere number regulation maintained after immobilization in desmin-null mouse skeletal muscle.

The serial sarcomere number of skeletal muscle changes in response to chronic length perturbation. The role of the intermediate filament desmin in regulating these changes was investigated by comparing the architectural adaptations of the tibialis anterior, extensor digitorum longus (EDL) and soleus from wild-type mice with those of homozygous desmin knockout mice after hindlimb immobilization. After 28 days, serial sarcomere number increased significantly in the lengthened wild-type tibialis anterior (by approximately 9%) and EDL (by approximately 17%). Surprisingly, muscles from desmin knockout mice also experienced significant serial remodeling, with the serial sarcomere number of the tibialis anterior increasing by approximately 10% and that of the EDL by approximately 27%. A consistent result was observed in the shortened soleus: a significant decrease in sarcomere number was observed in the muscles from both wild-type (approximately 26%) and knockout (approximately 12%) mice. Thus, although desmin is not essential for sarcomerogenesis or sarcomere subtraction in mouse hindlimb muscles, the results do suggest subtle differences in the nature of sarcomere number adaptation. We speculate that desmin may play a role in regulating the optimal arrangement of sarcomeres within the muscle or in sensing the magnitude of the immobilization effect itself.

Evaluation of light transmission and distribution materials for Lunar and Martian bioregenerative life support.

The materials that were selected and evaluated in this study in the context of bioregenerative advanced life support included polymer optical cables, for transmission of photosynthetic photon flux (PPF), and light pipe, woven optical pad and light-emitting fiber (LEF) for PPF distribution. All materials exhibited significant fidelity in transmitting the spectral characteristics of the artificial lluminator's Xenon-Metal Halide lamp. The PPF attenuation values for the polymer cables EL-200, EL-300, EL-400, and EL-500 were not significantly distinguishable from one another nor from that of the fused-silica cable of 0.34 dB/m. With the exception of EL-100 and EL-700, which had significantly lower PPF transmission efficiencies of 54.9%/m and 66.6%/m, respectively, all the other polymer cables had PPF transmission efficiencies of over 85%/m which, except for EL-300, were not significantly different from one another nor from that of the fused-silica cable of 93.2%/m. The highest PPF output efficiency achieved for the 7.1-cm light pipe 14.7%, for its maximum pipe length of 100 cm. At a constant pipe length of 50 cm, the PPF output efficiency of the 10-cm light pipe of 0.71% was significantly lower than that of the 7.1-cm light pipe of 10.54%. The PPF output for the woven optical pad was determined to be 36.3%. The PPF output efficiency for the LEF without the optic fastener was determined to be 27.1%, whereas that for the LEF with the optic fastener was 50.3%, that is, the maximum value of PPF output efficiency in the study. The polymer optical cables, light pipe, woven optical pad, and LEF exhibited significant regularity and symmetry in their PPF output spatial distributions.

Characterizations of high-intensity red and blue light-emitting diodes (LEDs) as a light source for plant growth.

Recently developed high-intensity red and blue light-emitting diodes (LEDs), which constitute a potentially improved light source for controlled-environment plant growth applications such as in vitro micropropagation and biologically based advanced life support (ALS) for space missions, were characterized in this study. Blue 2 LED and Red 1 LED consistently yielded the highest and lowest voltage drop readings, respectively, for all the electrical current settings tested (5-50 mA), with Blue 1 LED producing voltage drops falling nearly in the middle of the readings for the first two LEDs. At the standard current setting of 20 mA, Blue 2 LED and Blue 1 LED required 2.5 and 1.6 times more electrical power, respectively, than did Red 1 LED. At the standard current of 20 mA, the average photosynthetic photon flux (PPF) for Red 1 LED, Blue 1 LED, and Blue 2 LED were 180, 145, and 36 micromoles m-2 s-1, respectively. Red 1 LED peaked at 460 micromoles m-2 s-1 at 50 mA, Blue 1 LED at 200 micromoles m-2 s-1 at 40 mA, and Blue 2 LED at 40 micromoles m-2 s-1 at about 25 mA. For all current settings, the electrical conversion efficiency of Red 1 was approximately two times greater than that of Blue 1 LED. The electrical conversion efficiency of Blue 1 and of Red 1 LED peaked in between 10 and 20 mA, at about 13 mA for Blue 1 LED and at about 15 mA for Red 1 LED. The normalized PPF distributions for both Red 1 LED and Blue 1 LED were independent of the various magnitudes of electrical current (20, 30, 40, and 50 mA) that were applied to the LEDs.

Design parameters of flat-panel LED modules for plant lighting applications.

Semispherical high-intensity light-emitting diodes (LEDS) mounted on a circuit board have been developed and examined for plant growth applications. This type of LED configuration, however, has problems such as relatively poor heat dissipation, difficulty of effecting high light uniformity, and high cost of assembly. Such problems may now be obviated through use of the recently developed flat-panel LED modules. In this study, the photosynthetic photon flux (PPF) levels and PPF distribution of 172 x 27 mm red flat-panel LED modules were determined. Results showed that: 1) the red flat-panel LED modules tested produced a mean PPF level of about 111 micromoles m-2 s-1 at a distance of 10 cm, which would be adequate for most micropropagated species grown photomixotrophically and reasonable for some micropropagated species grown photoautotrophically, both in terms of red wavelength; 2) the mean surface PPF of 419 micromoles m-2 s-1 for a single LED in a flat-panel module was about 47% greater than that for a single semispherical LED at about equal operational currents, owing primarily to the significantly larger reflectance area present in a flat-panel LED than that in a semispherical LED; 3) two flat-panel LED modules tested had about 80% of their illuminated areas having PPF values equal to or greater than half their maximum PPF levels, whereas the third module had a corresponding figure of about 67%; and 4) flat-panel LED modules exhibited very similar PPF distributions, underscoring the advantage of the LED flat-panel design over the manually assembled LED array in the ease of replicating light distributions.

Serious illness and private health coverage: a unique problem calling for unique solutions.

Authors examine the experience of two nonelderly adult populations in Indiana and their difficulties in obtaining and retaining health insurance once diagnosed with a serious chronic or catastrophic disease.

Tort liability for managed care: the weakening of ERISA's protective shield.

In light of recent developments in the law of ERISA preemption, author assesses the extent to which litigants are successfully imposing tort liability on HMOs and MCOs.

Effect of ammonia on the quantitative clearance of Escherichia coli from lungs, air sacs, and livers of turkeys aerosol vaccinated against Escherichia coli.

Turkeys were given an aerosol vaccine to determine their ability to clear a virulent inhaled pathogenic strain of Escherichia coli, while they were being maintained in the presence of atmospheric NH3. Turkeys were exposed to 2 concentrations of NH3 (10 and 40 microliters/L of air). More E coli was found in lungs, air sacs, and livers of turkeys exposed to NH3. Turkeys not exposed to NH3 had better clearance of E coli. Vaccination against E coli improved the rate of clearance of E coli in birds not exposed to NH3.

Scanning electron microscopic studies of adverse effects of ammonia on tracheal tissues of turkeys.

Effects of 10 and 40 microliter of NH3/L of air (10 and 40 ppm) on the tracheal tissues of turkeys were examined under the scanning electron microscope. Turkeys maintained in the presence of either level of NH3 had deterioration of their normal mucociliary apparatus after prolonged exposure. Excessive mucous production, matted cilia, and areas of deciliation in the tracheal tissues were detected in birds exposed to NH3 concentrations as low as 10 microliters/L. The tracheal tissues of birds not exposed to NH3 appeared normal. The implications of respiratory tract damage caused by NH3 are discussed.

Epizootiological investigations of colibacillosis in turkeys.

One experimental and two field studies were conducted to assess the input of the three most common pathogenic serotypes of Escherichia coli (01a, 02a, and 078) via the hatch debris, environment of turkey buildings, and feed and water supplied these turkeys. Air samples were also taken to assess the environmental load in the experimental study. These studies revealed that in one field trial the input of E. coli 02a in conjunction with mild infections of Mycoplasma meleagridis (MM) and avian influenza (AI) contributed to an outbreak of acute colibacillosis with high mortality. E. coli 02a was isolated from the infected organs. At the processing plant, airsacculitis scores revealed lesions attributed mainly to MM. Lactose-broth rinsings of whole eviscerated turkeys indicated that pathogenic E. coli 01a and 02a could be detected at the time the turkeys are marketed.

The incidences of leg and foot abnormalities in Wrolstad White turkeys.

The leg and foot abnormalities of a flock of 911 Wrolstad White turkeys were described and were analyzed statistically to determine the relationship of the incidences of leg and foot abnormalities to sex and body weight of the turkeys. Body weight and a visual observation of the condition of legs and feet of each turkey were recorded at the age of nearly 12 weeks. The sex of each turkey had been recorded at one day of age. Based on chi-square contingency tables, the incidence of the leg and foot abnormalities was related to sex. The male turkeys were far more likely to experience leg and foot abnormalities than were the females. The incidence rate of severe leg and foot abnormalities was 16.1% for the males and 4.8% for females. The incidence of leg and foot abnormalities was not related to weight per se. The light turkeys of either sex were just as likely as the heavy turkeys of the same sex to have leg and foot abnormalities.