Biochemical Characteristics of The Na-alpha-Ketoglutarate Cotransport System in Proximal Convoluted and Straight Tubules of the Rabbit Kidney / 대한신장학회잡지

PURPOSE: alpha-Ketoglutarate (alphaKG), a Krebs cycle intermediate, is extensively used in the kidney as a fuel substrate and as a counter anion for organic acid secretion. It is known to be taken up by the proximal tubule cells via the brush-border as well as basolateral membranes. We explored biochemical characteristics of the brush-border and basolateral alphaKG transport systems in pars convoluta and pars recta of the proximal tubule, respectively. METHODS: Brush-border and basolateral membrane vesicles (BBMV and BLMV) were isolated from rabbit renal outer cortex and outer medulla by Percoll gradient centrifugation. Vesicular uptake of alphaKG was determined by rapid Millipore filtration method using alpha-14[C]KG as a substrate. RESULTS: Both BBMV and BLMV showed a Na-gradient dependent uphill transport of alphaKG. The systems in both membranes were similarly inhibited by Li and activated by Na (Hill coefficient of 1.4). Kinetic analyses indicated that the Na-alphaKG cotransporters in the BBMV had a lower substrate affinity as compared with those in the BLMV. The transport systems in BLMVs showed a similar Km but different Vmax between the outer cortex (Km: 34 uM, Vmax: 3.3 nmol/mg protein/10s) and outer medulla (Km: 37, Vmax: 1.8). On the other hand, the systems in BBMVs were different in both Km and Vmax between the outer cortex (Km: 194, Vmax: 3.3) and outer medulla (Km: 89, Vmax: 1.7). CONCLUSION: The findings suggest that both axial and apical to basolateral heterogeneity of the Na-alphaKG cotransport system in proximal tubules may be due to a physiological adaptation to efficiently utilize alphaKG in the kidney.

Transport of Tetraethylammonium in Renal Cortical Endosomes of Cadmium-Intoxicated Rats

Effects of cadmium (Cd) intoxication on renal endosomal accumulation of organic cations (OC ) were studied in rats using 14C-tetraethylammnium (TEA) as a substrate. Cd intoxication was induced by s.c. injections of 2 mg Cd/kg/day for 2-3 weeks. Renal cortical endosomes were isolated and the endosomal acidification (acridine orange fluorescence change) and TEA uptake (Millipore filtration technique) were assessed. The TEA uptake was an uphill transport mediated by H /OC antiporter driven by the pH gradient established by H -ATPase. In endosomes of Cd-intoxicated rats, the ATP-dependent TEA uptake was markedly attenuated due to inhibition of endosomal acidification as well as H /TEA antiport. In kinetic analysis of H /TEA antiport, Vmax was reduced and Km was increased in the Cd group. Inhibition of H /TEA antiport was also observed in normal endosomes directly exposed to free Cd (but not Cd-metallothionein complex, CdMt) in vitro. These data suggest that during chronic Cd exposure, free Cd ions liberated by lysosomal degradation of CdMt in proximal tubule cells may impair the endosomal accumulation of OC by directly inhibiting the H /OC antiporter activity and indirectly by reducing the intravesicular acidification, the driving force for H /OC exchange.

The Effect of Intra-articular Hyaluronic Acid and Steroid Injection in Osteoarthritis of the Knee

OBJECTIVE: To evaluate the efficacy of intra-articular hyaluronic acid and steroid injection in osteoarthritis of the knee. METHOD: Among 653 patients with osteoarthritis, 531 patients were participated in this study. They were divided to three groups; A, treated with hyaluronic acid 2.5 ml intra-articular injection once a week for 5 times; B, hyaluronic acid 2.5 ml once a week for 5 times with triamcinolone 20 mg once at the first time; C, only triamcinolone 20 mg at the first time. Before injection, X-ray with standing view were checked and divided according to Kellgren's grade of osteoarthritis. The amount of pain relief was assessed by pain rating score (PRS) and visual analogue scale (VAS) 1 week before and 1 month after the treatment. RESULTS: The degree of pain relief by PRS and VAS were all improved at 1 month after injection compared with pre-injection status (p<0.001). Intra-articular hyaluronic acid injection was more effective in Kellgren's grade I, II than in III, IV in pain relief and hyaluronic acid with steroid injection was more effective in III, IV. CONCLUSION: The results suggest that intra-articular hyaluronic acid injection would be effective for the treatment of patients with osteoarthritis.

Radiologic Measurement of Flatfoot

OBJECTIVE: This study was aimed to demonstrate definite diagnostic radiologic criteria between normal and flatfoot. METHOD: Sixty healthy subjects and fifty two flatfoot cases were evaluated by radiologic measurements. We evaluated criteria for longitudinal arch curve by measuring of calcaneal pitch, talocalcaneal angle, talometatarsal angle, metatarsal angle and navicular height I and II. RESULTS: Over 10 years old, there was significant correlation between normal group and flatfoot in calcaneal pitch, talocacaneal angle, difference angle, metatarsal angle, navicular height I and II. But below 10 years old, there was difference in only talometatarsal angle and metatarsal angle. Therefore talometatarsal angle and metartarsal angle are valuable in diagnosis of flatfoot in all age group. CONCLUSION: In diagnosis of flatfoot, variable radiologic measurement are clinically significant.

Ultrasonography in the Shoulder Impingement Syndrome

OBJECTIVE: The purpose of this study was to evaluate the ultrasonographic (US) findings in the shoulder impingement syndrome and to correlate them with the Hawkins and Kennedy's clinical stages. METHOD: 41 patients with suspected shoulder impingement syndrome were evaluated. All patients were divided into 3 clinical groups according to Hawkins and Kennedy and US examination was done in each group. RESULTS: US findings were as follows. In stage I, there were 3 normal findings, 5 tendinitis of the rotator cuff (RC), 2 partial thickness tear of RC, and 0 full thickness tear of RC. In stage II, 6 normal findings, 13 tendinitis of RC, 3 partial thickness tear of RC and 2 full thickness tear of RC. In stage III, 0 normal findings, 1 tendinitids of RC, 1 partial thickness tear of RC, and 5 full thickness tear of RC. The most common findings in the tendinits of RC were tendon thickness, focal hypoechogenicity and calcification. In partial thickness tear of RC, focal hypoechogenicity and impingement in abduction were most common findings. In full thickness tear of RC, the irregular humeral head surface and the biceps tendon effusion were most common findings CONCLUSION: The ultrasonography is a valuable means of evaluating the shoulder impingement syndrome and its findings have good correlation with clinical stages

Usefulness of Questionnaires, Physical Examination and Median Mixed Nerve Conduction Studies in Patients with Diabetes Mellitus

OBJECTIVE: To find simple screening method for assessment of patients with diabetic neuropathy by use of brief questionnaire, scored physical examination including vibration perception threshold, and mixed median conduction study. METHOD: Subjects were 24 patients with diabetes mellitus. Conventional nerve conduction study was performed in 24 patients and the patients were divided into two groups: 11 patients with polyneuropathy; 13 patients of normal findings. The questionnaires were given for evaluation of sensory function in all the subjects. The questionnaires were followed by physical examination including two point discrimination, vibration perception threshold by using biothesiometer, 10 gram filament test, pin prick test, DTR check, and muscle strength test. Abnormality was determined by the number of positive responses or abnormal clinical findings. Finally, we recorded the conduction velocity and amplitude of median mixed nerve and compared these parameters to values of 20 normal adults. RESULTS: The questionnaire and physical exam scores were higher in patients with polyneuropathy (p<0.01). The patients with polyneuropathy showed higher vibration perception threshold values (p<0.01) and slower conduction velocity and smaller amplitude of median mixed nerve (p<0.05). In correlation with conventional nerve conduction study, the median mixed nerve conduction velocity had higher kappa value than amplitude in screening for diabetic polyneuropathy. CONCLUSION: We suggest the questionnaires, scored physical examination, vibration perception threshold, and median mixed nerve conduction velocity to be a simple screening method for assessment of patients with diabetic plyneuropathy.

Muscle Fiber Conduction Velocity and Histopathologic Findings after Intramuscular Injection with 7% Phenol Solution in Rat

OBJECTIVE: To investigate the muscle fiber conduction velocity and histopathologic changes in skeletal muscle after 7% phenol solutions intramuscular injection. METHOD: Forty-five Sprague Dawley rats were divided into two groups: Experimental group, 30; Control group, 15. Experimental and control groups were injected with 0.1 cc of 7% phenol solution and 0.9% saline in right gastrocnemius, respectively. The histopathologic findings and muscle fiber conduction velocity were evaluated at 0, 1, 5, 14, and 28 days after each injection. RESULTS: In the light microscopic examination of experimental groups, vacuolar change, atrophy of myofibers, and intermyofiber cell proliferation were shown. The expression of synaptophysin began to be seen at 5 days and S-100 protein was increased 14 days after injection. In the electron microscopic examination of experimental groups, vacuolar change and denuded postsynaptic membrane were shown. In muscle fiber conduction study of experimental groups, the mean velocity were significantly slowed at 1, 5, 14, and 28 days after injection than those of control groups (p<0.05). CONCLUSION: On the basis of histopathologic findings, it is presumed that the mechanisms of paralysis following intramuscular injection of 7% phenol solutions were both myogenic and neurogenic. The slowing of muscle fiber conduction velocity tended to be related with the histopathologic changes of skeletal muscles after intramuscular injection with 7% phenol solution.

Histopathologic Findings and Muscle Fiber Conduction Studies after Intra-muscular Injection of Botulinum Toxin in Rat

Recently, botulinum toxin has been widely used for the management of spasticity. However it's mechanism of action in the skeletal muscle has not been well clarified. This study was performed to investigate the histopathologic changes in the skeletal muscle after botulinum toxin injection, and to determine the clinical standards of muscle fiber conduction study as an objective indicator for the changes of muscle fiber. As a study group, 35 Sprague Dawley rats were injected intra-muscularly with the botulinum toxin type A around two heads of right gastrocnemius muscle. After the injection of botulinum toxin, histopathologic studies and muscle fiber conduction studies were performed in 5 rats of the study group at 0, 1, 3, 5, 7, 14, and 28th day respectively. Based on the morphologic studies, the mechanisms of paralysis following the botulinum toxin injection were found to be both myogenic and neurogenic, and the motor function recovered through the formation of new motor end-plate and proliferation of Schwann cells. The muscle fiber conduction study revealed that the mean latencies of study group at 1, 3, 5, 7, and 14th day after the injection of botulinum toxin were significantly prolonged than those of the control group(p<0.05). The prolongation and slow recovery of latencies in a muscle fiber conduction study after the injection of botulinum toxin significantly reflect the morphologic changes of paralized skeletal muscles.

Comparisons between Clinical, Radiologic and Electrodiagnostic Findings in the Low Back Pain Patients

The authors reviewed the diagnostic use of clinical findings on physical examination, electrodiagnostic data, and radiologic findings including magnetic resonance imaging (MRI) in 55 patients with low back pain (LBP). Radiologic parameters included the lumbar lordosis, lumbosacral joint angle, and disc height narrowing. Clinical parameters included straight leg raising test, motor and sensory tests, and deep tendon reflxes (DTRs) on physical examination. MRI findings were classified 6 categories as bulging, protruded, extruded, sequestered, normal, and multiple level. In 35 cases of radiculopathy group, the severity of herniated intervertebral disc was well correlated with some of clinical and radiologic parameters, such as motor weakness, sensory or DTR abnormalities, and L5/S1 disc height. There was no correlations between MRI and electrodiagnostic findings on the site of the root lesions in all but 10 cases(18.2%). We suggest that the electrodiagnostic studies should be performed routinely as part of LBP evaluation for the identification of site and degree of radiculopathy.