T-cell clones derived by CD3 stimulation from hepatitis C virus explanted liver tissue are not representative of dominant clones present in vivo.

Liver tissue from hepatitis C virus (HCV)-related end-stage disease contains T-cell infiltrates. The goal of this study is to determine whether CD4 T-cell clones established in vitro using an antigen-independent technique from explanted liver tissue (n = 3) are representative of dominant clones present in vivo. T-cell receptor (TCR) use by intrahepatic CD4 T cells was assessed by spectratype analysis. Clones were established from single CD4 T cells by culturing in vitro with anti-CD3 and interleukin-2 (n > 25 per patient). TCR genes expressed by each clone were identified by sequencing. When identical clones were isolated, the original spectratype was analyzed further to determine whether the clone was a dominant T-cell expansion in vivo. Evidence for clonal expansions was found in all patients by spectratyping. T cells expressing the same TCRBV genes used for spectratyping were cloned in vitro. Duplicate clones expressing the same TCR genes were observed in 2 patients. Confirmation that clones established in vitro matched those present in vivo was obtained for 2 clones. Many dominant clones identified by spectratyping did not proliferate in vitro. Although spectratyping suggested the widespread accumulation of clonal expansions in HCV-related end-stage liver disease, clones established in vitro using anti-CD3 were poorly representative of dominant clones present in vivo. Although cloning with anti-CD3 has the advantage of generating T-cell clones not biased a priori toward a specific antigen, modified cloning strategies will need to be developed to expand those clones that appear dominant in end-stage organs.

The relationship between clinical and MRI findings in patients with unilateral temporomandibular joint pain.

BACKGROUND: With the advent of magnetic resonance imaging, or MRI, clinicians and researchers have sophisticated techniques by which to assess the anatomy of the temporomandibular joint, or TMJ. Imaging is indicated when the results will affect the patient's care beyond that which can be gained from a complete clinical assessment. One of the primary indications for treatment of patients with temporomandibular disorders, or TMDs, is jaw pain, including TMJ pain. Therefore, it is necessary to assess whether MRI-depicted TMJ findings are associated with TMJ pain. This study assessed the relationship between TMJ pain and clinical and MRI findings. METHODS: Subjects consisted of 85 patients with unilateral jaw pain in the area of the TMJ. The contralateral, nonpainful TMJ served as the matched control. All patients underwent a complete stomatognathic examination that included palpation of both TMJs. No care was given and no anti-inflammatory medications were prescribed until bilateral MRIs were obtained within one week. RESULTS: The authors found significant relationships between the side of reported jaw pain and the patient's report that palpation of the TMJ was painful and between the side of reported pain and the presence of MRI-detected effusions. The authors found no relationship between the side of reported pain and the presence of a disk displacement, or DD, or between the presence of effusions and DD on either side of the jaw. CONCLUSION: Although MRI-depicted effusions of the TMJ were associated with reports of TMJ pain, there was a high level of false-positive and false-negative findings. The results indicate that palpation of the TMJ is more accurate than MRI-depicted effusions in identifying the TMJ as the source of pain for patients with unilateral jaw pain. CLINICAL IMPLICATIONS: The results of this study suggest that palpation of the TMJ is superior to MRI in identifying the joint as the source of pain. Therefore, the most cost-effective and valid test to determine if the TMJ is a source of jaw pain is a complete clinical assessment.

Hyaluronic acid enhances peripheral nerve regeneration in vivo.

Hyaluronic acid has been shown to enhance peripheral nerve regeneration in vitro. It has been proposed that, during the fibrin matrix phase of regeneration, hyaluronic acid organizes the extracellular matrix into a hydrated open lattice, thereby facilitating migration of the regenerating axons. Hyaluronic acid solutions and saline control solutions were injected into a nerve guide spanning a transected gap in the sciatic nerve of Sprague-Dawley rats (five in each group). Nerve conduction velocities were measured at 4 weeks by electromyography (EMG) before sacrifice of the animals. These studies demonstrated increased conduction velocities in the hyaluronic acid group compared with control animals (P = 0.006). After the animals were sacrificed, regenerated axon cables were quantified histologically, and axon branching was delineated by retrograde tracer analysis. In addition, the hyaluronic acid group showed an increase in myelinated axon counts at 4 weeks (P= 0.03). An increase in retrograde flow was demonstrated in the hyaluronic acid groups compared with animals receiving saline solution.

Effect of Schwann cells in the enhancement of peripheral-nerve regeneration.

Schwann cells appear to stimulate the early phases of axon regeneration. The reported study investigated whether nerve guides with Schwann-cell monolayers can help regenerating nerves span gaps larger than 1 cm. Schwann-cell cultures were established by resecting 1-cm segments of sciatic nerves of adult female Sprague-Dawley rats, establishing cell monolayers in 24-mm nerve guides, and then reinserting these "living guides" into 20-mm nerve gaps of the rats from which they were developed. Control groups had plain guides (no Schwann cells) inserted between the same 20-mm gaps. In the experimental group, resected nerves regrew progressively. At 8 weeks, regrowth had spanned the entire gap in 60 percent of the animals. Axon counts increased at each successive time point. Regeneration did begin to occur in the control group but by 8 weeks, those cables had atrophied. The experimental groups displayed more central connections and higher nerve conduction velocity. Explant organ cultures of rat sciatic nerve can be used to develop nonneural conduits with Schwann-cell monolayers. These living artificial nerve guides permit the spanning of gaps of at least 20 mm.

The prevalence and treatment needs of subjects with temporomandibular disorders.

A cross-sectional study of prevalence of temporomandibular joint (TMJ) internal derangements, muscle disorders, and associated TM signs and symptoms was completed on 269 female nursing students. The prevalence of specific stages of internal derangements of the TMJ and muscle disorders was estimated, using established diagnostic criteria. The levels of dysfunction and symptomatology associated with each diagnosis were estimated with previously established indexes. When subjects with symptoms were asked if they had previous treatment for a TMJ problem, 6.7% responded positively. When subjects with symptoms who had not had treatment were asked why they had not sought treatment, most responded that it was not a problem or they could live with the symptoms. Thus, most subjects with clinically detectable dysfunction are functioning adequately without significant symptoms and do not need treatment.

Structural and functional correlates of effects of angiotensin-induced changes in rat glomerulus.

The effects of systemically infused angiotensin II (ANG II) (5, 50, and 100 ng X min-1 X 100 g body wt-1; groups 1, 2, and 3, respectively) were studied in Sprague-Dawley rats. All doses increased systemic blood pressure, fractional excretion of sodium, and urine flow rate but decreased glomerular filtration rate. Scanning electron microscopy revealed no detectable changes in the visceral epithelium or measurable alterations in the total area of endothelial capillary surface occupied by pores. Glomerular basement membrane surface densities of outer (OCG) and inner (ICG) cortical glomeruli averaged 0.22 micron2/micron3 of glomerular tuft volume in all groups. Volume ratios of the individual glomerular tufts to that of their Bowman's capsule of OCG were less (P less than 0.05) in groups 1 and 2 (52 +/- 3 and 63 +/- 9%) than the control group (72 +/- 1%). The volume fraction of the glomerular capillaries to their Bowman's capsules remained approximately 25% in all groups. However, the volume fraction of parenchyma to Bowman's capsule was reduced in group 1 to 30 +/- 4% and 38 +/- 5% in group 2 compared with the control value of 47 +/- 2% (P less than 0.05). Thus ANG II reduced glomerular tuft volume and parenchyma but did not alter filtration surface area or capillary endothelial epithelial surface characteristics.

The aging male rat: structure and function of the kidney.

The progression of anatomic and functional changes that occur with aging in normal male Sprague-Dawley rats was investigated. Renal function studies were followed by vascular perfusion fixation of the kidneys. The kidneys were examined with light microscopy and scanning and transmission electron microscopy. The glomerular filtration rate of 12-month-old rats (0.30 +/- 0.06 ml/min/100 gm body weight) was significantly lower (P less than .05) than the rates of the 3-month-old (0.91 +/- 0.08 ml/min/100 gm body weight) and 5-month-old (0.99 +/- 0.16 ml/min/100 gm body weight) rats. Urine protein levels were moderately elevated in 12-month-old rats. Structural changes mainly involved the renal corpuscle and proximal tubule. The parietal layer of Bowman's capsule was transformed from a squamous to a columnar epithelium resembling that of the proximal tubule in 48% of the capsules surveyed in 12-month-old rats. This value was significantly higher (P less than .05) than that of the 5- (14%) or 3- (6%) month-old rats. Thin sheets of cytoplasm extended from podocytic cell bodies over the layer of pedicels. The proximal tubule displayed focal areas of cell injury and necrosis. Basement membranes associated with the renal corpuscle, glomerulus, and proximal tubule were considerably thickened in the oldest group of rats. Some cellular infiltration occurred in the interstitium. Therefore, kidneys of aging Sprague-Dawley rats exhibited capsular metaplasia, death, and injury of proximal tubular epithelial cells, and other structural changes not seen in younger animals. Some of these changes may underlie the functional deterioration of their kidneys.

Morphologic changes in uranyl nitrate-induced acute renal failure in saline- and water-drinking rats.

The sequential changes in renal morphology that occurred for 5 subsequent days after a subcutaneous injection of uranyl nitrate (10 mg. per kg.) were examined in saline- and water-drinking rats using light microscopy, transmission electron microscopy, and scanning electron microscopy. The cortical proximal tubule exhibited diffuse focal brush border loss and increased vacuolization by 1 hour after administration of the nephrotoxin. By 5 days, the P2 and P3 segments were completely necrotic. Cells of P1 segments accumulated large vacuoles throughout their cytoplasm, and distal nephron segments exhibited considerable cellular swelling and vacuolization. Scanning electron microscopy revealed abnormalities in glomerular epithelial cells similar to those seen in humans with chronic renal disease and in experimental animal models characterized by proteinuria. There was essentially no difference in the morphologic response of saline- and water-drinking rats. Although uranyl nitrate administered at this dosage resulted in the relatively slow development of tubular necrosis, changes in renal morphology could be seen within an hour and progressed insidiously throughout the study with little evidence of regeneration.

The long-term effects of uranyl nitrate on the structure and function of the rat kidney.

Studies were undertaken to determine the long-term effects of the nephrotoxin, uranyl nitrate, on the function and structure of the rat kidney. Animals were injected with 10 mg/kg B.Wt. of uranyl nitrate and renal function studies were performed one, two, four and eight weeks after drug administration. Light microscopy and scanning and transmission electron microscopy were used to characterize the morphologic changes at each time interval. Glomerular filtration rate was significantly reduced (P less than 0.01) one week (0.18 +/- 0.06 ml/min/100 gm B.Wt.) and two weeks (0.54 +/- 0.09 ml/min/100 gm B.Wt.) after drug treatment compared to controls (1.01 +/- 0.4 ml/min/100 gm B.Wt.) and returned to normal values by four weeks. The fractional excretion of sodium was significantly increased (P less than 0.01) one week after uranyl nitrate treatment (2.45% +/- 0.82) compared to controls (0.29% +/- 0.11). No further differences in this parameter were noted after one week. At all time intervals studied the pars recta of the proximal tubule (S2 and S3 segments) was the most consistently damaged region of the nephron. Acute tubular necrosis and tubular regeneration of these segments were evident one and two weeks after drug administration. Many of the tubules were widely dilated and lined by low-lying squamous epithelial cells. By four weeks some of these pars recta segments could be classified as microcysts and this type of lesion persisted as long as eight weeks after treatment. Regeneration of most injured proximal tubules was complete by eight weeks. Atrophic proximal tubules, marked interstitial fibrosis and a mononuclear cell infiltration, consistent with a chronic type of injury, were noted at the later time intervals. These results suggest that uranyl nitrate induces a persistent injury to the kidneys of rats causing lesions as long as eight weeks after injection.