DNA analysis of HLA-DR, DQ and DP genes in pauciarticular juvenile rheumatoid arthritis.

HLA-DR, DQ, and DP alleles were determined by restriction fragment length polymorphism (RFLP) and oligonucleotide hybridization analysis in 50 Caucasian children with pauciarticular juvenile rheumatoid arthritis (PaJRA) and 82 controls. There was an increased frequency of DR5, DRw8, and DQw4, as well as individual DQ alpha and beta chains, DQA*0401 and DQB1*0402, respectively, in this group of patients. There was an absolute association between DRw8, DQw4, DQA1*0401, and DQB1*0402 in the patient population. HLA-DPw2.1 was also increased in frequency. There was little evidence of linkage disequilibrium found between DPw2.1 and DR5, DRw8, or DQw4. These MHC Class II associations were more characteristic of those patients with young age of onset (less than 5 years), rather than those with onset greater than or equal to 5 years of age. Our data confirmed the previous associations of HLA-DR5, DRw8, and DPw2.1 with PaJRA and suggested a new association for DQ alpha and beta genes in the clinical expression of this disease.     

Perceptions of the at-risk nonsmoker: are potential intervention topics being overlooked?

This research is supported in part by Arizona Disease Control and Research Commission (ADCRC), Grant #9904 (M. Burgoon, PI). This study assesses how adolescent nonsmokers, at-risk smokers, and smokers differ in perceptions of smoking harms, benefits, and safety. While small differences exist when comparing attitudes and knowledge concerning short- and long-term benefits of smoking, large differences arise when attitudes and knowledge concerning the short-term benefits and the safety of casual smoking are compared.     

Ainhum (dactylolysis spontanea): A Radiological survey of 6000 patients

Dactylolysis spontanea is an idiopathic condition affecting the fifth toe, and sometimes other toes, that is frequently bilateral, with lesions in different stages. Between 1977 and 1999, a total 6000 radiographic studies of the feet were reviewed in a mainly African American population in Chicago, Illinois. After an initial screening based on the Cole criteria, 581 patients were selected and re-examined, and amplification techniques were performed. After reviewing the complementary exams, 102 patients were diagnosed with dactylolysis spontanea or ainhum. Soft-tissue constriction was the most frequently presented radiological sign on the initial screening. Kurtosis at the digit plantar fold and marked rotation of the fifth toe were normal findings in asymptomatic patients. Demographics, comorbidities, and radiological findings were analyzed in the selected population. Associated diseases occurring in these patients appeared to have no specific etiologic correlation with ainhum. African Americans and the dark-skinned population are affected exclusively by this condition, presumably due to the fibrogenic tendency of these individuals. Early diagnosis and accurate staging of ainhum are facilitated by radiological examination of the feet. The findings suggest that this condition is underdiagnosed and overlooked because its low prevalence and variable clinical presentations that might mimic more common etiologies, including localized trauma.     

Blood coagulation, fibrinolytic and inhibitory profiles in renal transplant recipients: comparison of cyclosporine and azathioprine.

Renal transplant recipients treated with cyclosporine (CS) have been reported to be at increased risk of thrombotic complications. The present study was intended to examine the blood coagulation, fibrinolytic, and inhibitory systems in such patients. Eight transplant recipients on maintenance immunosuppression with CS and prednisone were studied. Five transplant recipients maintained on azathioprine (AZA) and prednisone and 32 normal volunteers served as controls. Plasma antigen concentrations and/or activities of various proteins in the above pathways were measured. Both the CS and AZA groups exhibited significant elevations of factor IX activity, von Willebrand factor (vWF), D-dimer, protein C and tissue type plasminogen activator (t-PA) levels when compared with the normal controls. In addition, CS group showed a significant elevation of alpha 2-macroglobulin activity and AZA group showed a significant reduction in factor XII activity when compared with the normal controls. Comparison of data from CS and AZA groups revealed higher factor XII activity and vWF concentration in the former group. In conclusion, transplant recipients treated with long-term cyclosporine and prednisone exhibited significant elevation of plasma vWF, D-dimer and protein C concentrations. In addition, both CS and AZA-treated transplant recipients showed increased plasma concentrations of D-dimer and t-PA. The latter observations suggest in vivo thrombin generation, fibrin formation and degradation.     

A review of the effects of expansion of the nasal base on nasal airflow and resistance.

PURPOSE: The purpose of this article is to inform the reader of the current literature regarding nasal airflow resistance. The anatomy and physiology of nasal airflow resistance will be examined and the known effects of widening of the nasal airway upon airflow will be described. MATERIALS AND METHODS: This article is a review of the current literature regarding nasal airflow and resistance and the effects of widening of the nasal base. No patient data were collected. RESULTS: The literature shows that nasal airflow resistance can be changed by surgical manipulation and by rapid palatal expansion, but that the effects on airflow resistance and future growth and development are unpredictable. CONCLUSION: Patients with a maxilla that is constricted in the transverse dimension and nasal airflow problems may benefit from expansion of the nasal base. The resultant effects upon nasal airflow resistance and subsequent growth and development are unpredictable and therefore airflow issues alone may not be a primary reason to increase the transverse dimension of the nasal base.     

Effects of polyethylene on macrophages

A system was developed to expose macrophages to polyethylene in vitro. Exposure of macrophages to these particles in isolation led to the release of tumor necrosis factor alpha and prostaglandin E₂. Exposure of macrophages in co-culture with osteoblasts to polyethylene particles increased the release of prostaglandin E₂ and also led to the release of interleukin-6. Incubation of radiolabelled calvariae with conditioned medium from macrophages exposed to polyethylene particles alone or to particles in co-culture with osteoblasts led to bone resorption reflected by release of ⁴⁵Ca. Incubation with pamidronate was effective in inhibiting resorption stimulated by conditioned medium from macrophages exposed to these particles alone or in co-culture with osteoblasts. This demonstrates that pamidronate, or other bisphosphonates, may be effective in inhibiting bone resorption at the implant/bone interface in association with the macrophage ressponse to particulate polyethylene. Further investigation into the possible use of pamidronate or other bisphosphonates in the treatment of aseptic loosening is warranted.     

NMDA Receptor Activation Triggers Voltage Oscillations, Plateau Potentials and Burstinq in Neonatal Rat Lumbar Motoneurons ln Vitro

Whole-cell recordings of lumbar motoneurons in the intact neonatal rat spinal cord in vitro were undertaken to examine the effects of Kmethyl-D-aspartate (NMDA) receptor activation on membrane behaviour. Bath application of NMDA induced rhythmic voltage oscillations of 5.9 ± 2.1 mV (SD) at a frequency of 4.4 ± 1.5 Hz. Amplitude, but not frequency, of the voltage oscillations was membrane potential-dependent. Voltage oscillations could recruit action potentials and/or plateau potentials with or without superimposed bursting. Blockade of synaptic transmission with tetrodotoxin (TTX) sometimes resulted in a loss of oscillatory activity which could then be restored by increasing the NMDA concentration. After application of TTX, the trajectory of NMDA-induced oscillations was similar to the trajectory induced in the presence of intact synaptic networks, although the mean oscillation duration was longer and the oscillation frequency was slower (1.8 ± 1.1 Hz). Current ramps delivered after bath application of NMDA demonstrated bistable membrane properties which may underlie the plateau potentials. Injection of intracellular current pulses could initiate, entrain and terminate individual plateau potentials. The results suggest that membrane depolarization produced by oscillations may activate other intrinsic conductances which generate plateau potentials, thereby providing the neuron with enhanced voltage sensitivity, compared to that produced by NMDA receptor activation alone. These oscillatory events may have a role in the regulation of motor output in a variety of rhythmic behaviours including locomotion.