Oral tolerance in protein-deprived mice. I. Profound antibody tolerance but impaired DTH tolerance after antigen feeding.

We have examined the effects of protein deprivation on the induction of oral tolerance for systemic antibody and DTH responses to the protein antigen ovalbumin (OVA). Mice were fed 4% or 24% protein diets from weaning and given a single feed of OVA 2 weeks later (short-term deprivation) or after 10 weeks (long-term deprivation). Tolerance for serum antibody responses was more profound in protein-deprived animals than in 24% protein-fed control groups. Conversely, tolerance for DTH responses was impaired in protein-deprived mice. This was demonstrated both for short-term deprivation, where nutritional rehabilitation after OVA feeding was necessary to demonstrate this effect on DTH, and for long-term deprivation. Furthermore, the effect of short-term deprivation on tolerance for DTH responses was similar to that observed after cyclophosphamide pretreatment of OVA-fed mice. Protein deprivation has disparate effects on the humoral and cell-mediated limbs of oral tolerance, and our results support the hypothesis that this regime selectively depletes a population of suppressor T cells responsible for the fine control of DTH tolerance.     

Giant cell tumor of bone express p63.

p63 contributes to skeletal development and tumor formation; however, little is known regarding its activity in the context of bone and soft tissue neoplasms. The purpose of this study was to investigate p63 expression in giant cell tumor of bone and to determine whether it can be used to discriminate between other giant cell-rich tumors. Seventeen cases of giant cell tumor of bone were examined to determine the cell type expressing p63 and identify the isoforms present. Total RNA or cell protein was extracted from mononuclear- or giant cell-enriched fractions or intact giant cell tumor of bone and examined by RT-PCR or western blot, respectively. Immunohistochemistry was used to evaluate p63 expression in paraffin embedded sections of giant cell tumor of bone and in tumors containing multinucleated giant cells, including: giant cell tumor of tendon sheath, pigmented villonodular synovitis, aneurysmal bone cyst, chondroblastoma, and central giant cell granuloma. The mononuclear cell component in all cases of giant cell tumor of bone was found to express all forms of TAp63 (alpha, beta, and gamma), whereas only low levels of the TAp63 alpha and beta isoforms were detected in multinucleated cells; DeltaNp63 was not detected in these tumors. Western blot analysis identified p63 protein as being predominately localized to mononuclear cells compared to giant cells. This was confirmed by immunohistochemical staining of paraffin-embedded tumor sections, with expression identified in all cases of giant cell tumor of bone. Only a proportion of cases of aneurysmal bone cyst and chondroblastoma showed p63 immunoreactivity whereas it was not detected in central giant cell granuloma, giant cell tumor of tendon sheath, or pigmented villonodular synovitis. The differential expression of p63 in giant cell tumor of bone and central giant cell granuloma suggest that these two tumors may have a different pathogenesis. Moreover, p63 may be a useful biomarker to differentiate giant cell tumor of bone from central giant cell granuloma and other giant cell-rich tumors, such as giant cell tumor of tendon sheath and pigmented villonodular synovitis.     

Real-time nucleic acid sequence-based amplification using molecular beacons for detection of enterovirus RNA in clinical specimens

Real-time nucleic acid sequence-based amplification (NASBA) using molecular beacon technology (NASBA-beacon) was compared to standard NASBA with postamplification hybridization using electrochemiluminescently labeled probes (NASBA-ECL) for detection of enteroviruses (EV) in 133 cerebrospinal fluid and 27 stool samples. NASBA-ECL and NASBA-beacon were similar in sensitivity, detecting 55 (100%) and 52 (94.5%) EV-positive samples, respectively. There were no false positives. Both NASBA assays were significantly more sensitive than culture. Real-time NASBA-beacon reagents and equipment rental were more expensive than those for NASBA-ECL; however, time to result was shortened by 1.5 h, hands-on time was reduced by 25 min, and the assay was much simpler for technologists to learn and perform.     

Increasing transplant mass results in long-term allograft survival and recovery from transplant vasculopathy

Late allograft rejection due to transplant vasculopathy continues to be a major clinical problem. Increasing the ratio of donor transplant size to recipient weight has been shown to reduce the incidence of late allograft failure. Using a murine pancreas transplant model we have tested the hypothesis that increasing the donor transplant size in a recipient can promote long-term allograft survival by promoting recovery from transplant vasculopathy. Recipients of an allograft that showed extensive vasculopathy were transplanted with a second donor transplant. The effect of the second allograft on the vasculopathy present in the first graft was measured. Transplanting a second allograft reversed all signs of ongoing rejection, including transplant vasculopathy, resulting in long-term survival of the first graft. Vasculopathy was only reversed if the first and second grafts were from the same mouse strain, suggesting an antigen-specific mechanism. However, the recovery of the first graft was not associated with antigen-specific peripheral tolerance.     

End-stage renal disease and race: an overview and perspective

The epidemiology of end-stage renal disease (ESRD) in the United States is reviewed. Hypertension and diabetes as etiologic factors in ESRD in minorities are discussed, as is the question of a familial ESRD. It is hypothesized that diuretics as sole antihypertensive therapy in blacks may in the long term result in chronic volume contraction, increased sympathetic stimulation, and therefore, decreased renal function. As such, a rational basis for the long-term use of diuretics as the sole antihypertensive therapeutic in blacks becomes questionable at best.     

Substance P-immunoreactive nerves in the rat kidney

Previously published data have indicated that in the rat, unlike other species examined, the kidney is not supplied by sensory nerves containing substance P (SP). As part of a study of reflex control of renal function in the rat, we have now reassessed this situation. Many fine, varicose, SP-immunoreactive nerve fibers were found in the wall of the proximal ureter and the renal pelvis, and around the larger renal blood vessels. Sparser populations of similar nerves were also seen running close to proximal and distal tubules in the renal cortex. Occasional fibers were seen at the margins of the glomeruli. Our findings suggest that sensory nerves containing SP may carry sensory information of several types from the rat kidney.     

A portable precision pumping system for chronic, programmed insulin infusion

This paper provides some details of a new insulin delivery system which includes a reservoir, a pump and a power pack. The reservoir holds 50 ml and is coupled to a precision peristaltic pump whose delivery can be set to any one of 128 different mean flow rates from 0 to 80 microliter/min (+/- 1.6% over 10 months) using the flow rate controller included in the battery power pack. The system weighs 525 g consuming 60 mW at the maximum pumping rate, proportionately less at lower rates. Ten pumps have undergone bench tests for 30 days. One has been subjected to an extended life test of 11 months while seven complete systems have been used on dogs to demonstrate their capability for precise longterm intravenous insulin therapy. With this system experimental diabetes has been reversed in 4 dogs for periods now extending beyond 6 months. This device now qualifies for long-term studies on hospitalized patients with diabetes mellitus.     

Skeletal muscle and cardiac changes with training in patients with angina pectoris

Cardiovascular and skeletal muscle adaptations were studied before and after 6 mo of physical training in patients with coronary artery disease and exertional angina pectoris. Symptom-limited exercise capacity increased by 41% (470 +/- 30 to 665 +/- 35 kg.m.min-1; n = 29, P less than 0.001) with training as did skeletal muscle succinate dehydrogenase activity (1.75 +/- 0.24 to 3.31 +/- 0.24 IU; n = 23, P less than 0.001) and the areas of muscle fibers (type I from 43.6 +/- 3.3 to 54.4 +/- 3.3 micrometers 2 X 10(2); n = 21, P less than 0.05 and type II from 43.9 +/- 2.4 to 57.2 +/- 5.1 micrometers 2 X 10(2); P less than 0.01). At the same submaximal exercise intensity (mean 355 +/- 100 km.m.min-1), plasma catecholamines (1.31 +/- 0.14 to 1.07 +/- 0.09 ng.ml-1; n = 13, P less than 0.05), heart rate (115 +/- 3 to 97 +/- 3 beats/min; n = 29, P less than 0.001), and systolic blood pressure (171 +/- 4 to 143 +2- 4 mmHg; n = 29, P less than 0.001) were significantly reduced after training. Maximal coronary sinus blood flow (192 +/- 10 to 208 +/- 9 ml.min-1; n = 29, P less than 0.05) and left ventricular oxygen consumption (23.2 +/- 1.5 to 25.8 +/- 1.6 ml.min-1; n = 24, P less than 0.05) were increased by 8 and 11%, respectively, after training. The improvement in exercise capacity with training in patients with exercise is secondary to a reduction in myocardial oxygen requirements during subangina levels of exercise and partly to a small increase in maximal myocardial oxygen consumption. The skeletal muscle adaptations with training were not related to other indices of training such as the reduced exercise heart rate or increased symptom-limited exercise capacity.     

Effects of a viral laryngotracheitis on the epithelial barrier of chicken airways

The effects of a virus infection on the barrier function of tracheal epithelium were compared to the effects of a chemical agent (methacholine) which selectively increases membrane permeability, and both were compared to controls. The disruption of the airway epithelium induced by the virus infection caused an increased permeation of horseradish peroxidase (HRP) through this barrier. Methacholine enhanced HRP uptake from the airway lumen to the blood as compared to controls. Visualization of HRP in the tracheal epithelium by transmission electron microscopy correlated with the radioimmunoassay measurements in the blood. Serial anti-HRP antibody titers were measured by a competitive binding technique. The antigen permeation induced by methacholine was associated with an enhanced anti-HRP antibody production. The larger increase in antigen permeation seen with the viral infection was associated with depressed anti-HRP titers. It was concluded that viral disruption of the airway epithelial barrier may contribute to an increased uptake of orally inhaled antigens. The relationship, however, between the increased antigen penetration consequent to the viral infection and the development of allergy remains unclear.     

The effects of hip contact aberrations on stress patterns within the human femoral head

A two-dimensional finite element model incorporating cancellous bone inhomogeneity is used to study femoral head stress alterations caused by changes from the usual articular contact patterns. The contact stress distributions, calculated from an earlier mathematical analysis by Greenwald and O'Connor (16), are found to influence not only the adjacent subchondral bone, but relatively distant parts of the head as well. Both abnormally large joint incongruity and abnormally low cartilage compliance cause load to shift away from the superior “weight-bearing” area, out toward the periphery of the contact region. As a consequence, transverse compressive stresses, which are of appreciable magnitude but which do not contribute to weight bearing, are built up throughout much of the superior and central portions of the femoral head. Most small changes in the overall cartilage thickness or in its thickness distribution, when considered in isolation from hip compliance changes, have only minor effects on the internal stress distribution. An important exception is cartilage thinning at the superior margin, which can result in abrupt longitudinal compressive stress concentrations. It is suggested that such alterations of the normal patterns of stress transmission may contribute to sclerosis or to the formation of osteophytes or cysts in the osteoarthritic hip. This study was aided by grants from the Easter Seal Research Foundation (#N7739), the National Science Foundation (#ENG78-05451), the Barra Foundation, Inc., and the Western Pennsylvania Chapter of the Arthritis Foundation. The authors wish to acknowledge the excellent service provided by the University of Pittsburgh Computer Center. The assistance of Mr. Gary E. Graf and Mrs. Diana W. Montgomery are also appreciated.