Control of Leishmania major by a monoclonal alpha beta T cell repertoire

Little is known regarding the diversity of the host T cell response that is required to maintain immunologic control of microbial pathogens. Leishmania major persist as obligate intracellular parasites within macrophages of the mammalian host. Immunity is dependent upon activation of MHC class II-restricted T cells to an effector state capable of restricting growth and dissemination of the organisms. We generated alpha-beta Leishmania-specific (ABLE) TCR transgenic mice with MHC class II-restricted T cells that recognized an immunodominant Leishmania Ag designated LACK. Naive T cells from ABLE mice proliferated in vitro after incubation with recombinant LACK or with Leishmania-parasitized macrophages and in vivo after injection into infected mice. Infected ABLE mice controlled Leishmania infection almost as well as wild-type mice despite a drastic reduction in the T cell repertoire. ABLE mice were crossed to mice with disruption of the TCR constant region alpha gene to create animals with a single alpha beta T cell repertoire. Although mice deficient in all alpha beta T cells (TCR-C alpha 0 mice) failed to control L. major, mice with a monoclonal alpha beta T cell repertoire (ABLE TCR-C alpha 0 mice) displayed substantial control. The immune system is capable of remarkable efficiency even when constrained to recognition of a single epitope from a complex organism.     

Magnetic resonance imaging and behavioral analysis of immature rats with kaolin-induced hydrocephalus: pre- and postshunting observations

The motor and cognitive dysfunction associated with hydrocephalus remains a clinical problem in children. We hypothesized that young rats with hydrocephalus should exhibit similar dysfunction and that the dysfunction should be reversible by shunting. Hydrocephalus was induced in 3-week-old rats by injection of kaolin into the cisterna magna. Rats were assessed by T2-weighted images obtained with a 7-T magnetic resonance device and by repeated behavioral testing including ability to traverse a narrow beam and ability to find a hidden platform in a water pool. Some of the rats underwent a shunting procedure 1 or 4 weeks after kaolin injection. Magnetic resonance images were used to measure ventricle size. They clearly demonstrated increased signal in periventricular white matter, which corresponded to increased brain water content. A flow-void phenomenon was observed in the cerebral aqueduct. Ability to traverse the beam did not correlate with the degree of ventriculomegaly. Ability to swim to the hidden platform demonstrated a progressive impairment of learning function which may have been accentuated by motor disability. When rats were shunted after 1 week, the behavioral dysfunction was prevented. Late shunting after 4 weeks was associated with gradual recovery of the behavioral disability which was not complete after 4 weeks. We conclude that early shunting is superior to late shunting with regard to behavioral dysfunction. High-resolution MR imaging shows features in hydrocephalic rats similar to those found in hydrocephalic humans.     

Stimulation of heparan sulfate proteoglycan synthesis and secretion during G1 phase induced by growth factors and PMA

Pulsatile tinnitus is a disorder that can be extremely disabling. Nonetheless, it has not been well-researched in the fields of psychology or behavioral therapy. This article describes the evaluation and behavioral treatment of a gentleman with pulsatile tinnitus. The evaluation included polygraphic assessment of vasomotor and electromyographic function both before and after treatment. The results show that the combination of lifestyle modifications and specific behavioral interventions were successful in modifying not only self-report indices of functioning, but also the underlying physiology related to the disorder. The potential role of the various treatment components and the value of including polygraphic assessment for informing treatment and evaluating outcome are discussed.     

Potential cost savings for Medi-Cal, AFDC, food stamps, and WIC programs associated with increasing breast-feeding among low-income Hmong women in California

OBJECTIVE: To determine the potential cost savings for four social service programs if breast-feeding rates increased among Hmong women in California. DESIGN: Cost-savings analysis. SUBJECTS/SETTING: Hmong women in California. In this population, breast-feeding is currently uncommon, and use of contraceptives is minimal. MAIN OUTCOME MEASURES: Savings were based on estimates of the resulting decrease in infant morbidity, maternal fertility, and formula purchases (Special Supplemental Nutrition Program for Women, Infants, and Children) if women breast-fed each child for at least 6 months. Costs were projected over a 7.5-year period and future values were discounted with annual interest rates of 2% or 4%. RESULTS: Substantial savings estimates were associated with breast-feeding for all four programs. The total projected savings over the 7.5-year period ranges from $3,442 to $4,944 (4% discount) to $4,475 to $6,0960 (0% discount) per family enrolled in all four programs. This translates into an estimated yearly savings of between $459 and $659 (4% discount) and $597 and $808 (0% discount) per family. APPLICATIONS: Although health care providers generally accept that breast-feeding is the preferred method for feeding infants, many still view the choice as a neutral one; that is, they consider low breast-feeding rates in the United States a cultural choice with no cost to society. This analysis provides evidence that breast-feeding is economically advantageous for individuals and society.     

Helminths of the Canadian toad, Bufo hemiophrys (Amphibia: Anura), from Alberta, Canada

Forty adult Bufo hemiophrys from Alberta, Canada, were examined for helminths. Four species were found: a trematode, Gorgoderina simplex, and 3 nematodes, Cosmocercoides variabilis, Oswaldocruzia pipiens, and Rhabdias americanus. Rhabdias americanus had the highest prevalence of helminths (73%); C. variabilis had the highest mean intensity (26+/-33 SD). Bufo hemiophrys represents a new host record for each species of helminth.     

The treatment of class III maxillary furcations using a resin-ionomer. A case report

This case report uses a resin-ionomer restoration as a barrier in the treatment of a Class III furcation defect. There was a reduction in tooth mobility and plaque count, no bleeding on probing, and a decrease in probing depth with the use of the resin ionomer. The study offers another treatment option in the treatment of a seemingly hopeless maxillary molar.     

A method to reduce response times in prehospital care: the motorcycle experience

This study compared the response times of a motorcycle and a standard ambulance in a congested urban emergency medical services (EMS) setting. The study was performed in Taipei, Taiwan, a densely populated urban area. A basic life support (BLS) motorcycle (without defibrillation capability) and an advanced life support (ALS) ambulance were based at three study hospitals and simultaneously dispatched when there was a perceived need for ALS ambulance transport. Over a 3-month period, prehospital personnel evaluated 307 medical and trauma emergencies. Time data were insufficient for analysis in 33 cases, leaving a study population of 274. Response times of the motorcycle and the ambulance were prospectively assessed and compared. During rush hours, the response times of the motorcycle and ambulance were 4.9+/-3.0 minutes and 6.3+/-3.4 minutes (P < .05), respectively, and in non-rush hours, 4.2+/-2.1 minutes and 5.1+/-2.5 minutes (P < .05), respectively. Using motorcycles to transport EMTs to the emergency scene significantly reduced response time compared with a standard ambulance in a congested urban setting. Large prospective studies are required to determine the impact on patient outcome of shorter EMS response times using motorcycles. EMS motorcycles appear feasible and deserve consideration to help expedite prehospital care in other systems in densely populated cities.     

Treatment of peri-implantitis using guided bone regeneration and bone grafts, alone or in combination, in beagle dogs. Part 1: Clinical findings and histologic observations

The purpose of this study was to evaluate and compare the treatment of ligature-induced peri-implantitis using guided bone regeneration and two bone grafts alone and in combination. Mandibular premolars and first molars were extracted from four beagle dogs and after 3 months of healing, three Br?nemark implants were placed on each side of the mandibles. Following abutment connection 3 months later, experimental peri-implantitis was induced by tying plaque-retentive ligatures around all abutments. Ligatures and abutments were removed after 3 months, and bony defects measured and treated with either: (1) debridement only; (2) debridement plus resorbable hydroxyapatite; (3) debridement plus canine freeze-dried demineralized bone; (4) debridement plus guided bone regeneration; (5) debridement plus resorbable hydroxyapatite and guided bone regeneration; or (6) debridement plus canine freeze-dried demineralized bone and guided bone regeneration. Pretreatment and 4-month-posttreatment comparison revealed a significant but variable degree of clinically appreciable hard tissue fill with all treatment procedures. Guided bone regeneration procedures resulted in the greatest fill, followed by bone grafts alone and flap debridement. There was no significant difference between guided bone regeneration and both guided bone regeneration/graft combinations; therefore, guided bone regeneration procedures appear to be a predictable treatment for plaque-induced peri-implant defects.     

Fine-structural alterations and clustering of developing synapses after chronic treatments with low levels of NMDA

In the visual pathway of frogs it is possible to apply low levels of NMDA chronically to the optic tectum and study the mechanisms underlying the stabilization of synapses developing within the CNS. Earlier studies (Cline and Constantine-Paton, 1990) found that chronic NMDA treatment of tecta innervated by two retinas results in a reduction of branching within the terminal arbors of retinal ganglion cells (RGCs). We now report that this same chronic NMDA treatment produces fine-structural changes in synaptic morphology as well as local synaptic rearrangements within the retinotectal neuropil. Chronic NMDA treatment of doubly innervated tecta was associated with a thickening or darkening of both pre- and postsynaptic densities. These changes in synapse morphology were restricted to the superficial neuropil of tecta in regions where reductions in branches of RGC axonal arbors were observed at the light microscopic level. The fine-structural effects were absent from similarly treated tecta innervated by only one eye, where RGC axonal arbor pruning was not observed. Stereological analyses indicated that the incidence of two or more presynaptic profiles converging on the same postsynaptic process was significantly increased in the NMDA-treated, doubly innervated tecta. This observed increase in synaptic clustering was not associated with a larger synaptic active zone, or with an increase in the number of synapses per unit volume. These data are discussed in the context of the hypothesis that chronic NMDA treatment raises the threshold for synapse stabilization in tectal neurons, causing the selective loss of poorly correlated synapses of both retinal and non-retinal origin from tectal neuropil that is innervated by two retinas: increased pre- and postsynaptic thickening could reflect greater efficiency in the remaining synaptic contacts and their closer spatial proximity on the same postsynaptic process is consistent with greater cooperativity and less competition.