Nitric oxide suppresses inducible nitric oxide synthase expression by inhibiting post-translational modification of I kappa B

The expression of inducible nitric oxide synthase (iNOS) is a critical factor in both normal physiological functions and the pathogenesis of disease. This study was undertaken to determine the molecular mechanism by which nitric oxide (NO) exerts negative feedback regulation on iNOS gene expression. Isolated rat hepatocytes stimulated with cytokines exhibited a marked increase in NO production as well as iNOS mRNA and protein levels, which were significantly reduced by pretreatment of the NO donors S-nitroso-N-acetyl-D, L-penicillamine (SNAP) and V-PYRRO/NO. This effect of SNAP was inhibited when NO was scavenged using red blood cells. Pretreatment with oxidized SNAP, 8-Br-cGMP, NO2-, or NO3- did not suppress the cytokine-induced NO production. Moreover, LPS/ IFN-gamma-stimulated RAW264.7 cells, which produce endogenous NO, expressed lower levels of iNOS, IL-1beta, IL-6 and TNF-alpha mRNAs, without changes in their mRNA half-lives, than those in the presence of the iNOS inhibitor NG-monomethyl- L-arginine. The iNOS gene transcription rate exhibited an 18-fold increase after cytokine stimulation, which was significantly inhibited by SNAP pretreatment. SNAP also blocked cytokine- induced increase in NF-kappa B activation, iNOS promoter activity, nuclear translocation of cytosolic NF-kappa B p65 subunit, and I kappa B alpha degradation, which correlated with its inhibitory effect on phosphorylation and ubiquitination of I kappa B. These data indicate that NO down-regulates iNOS gene expression and NO production by inhibiting the post-translational processes of I kappa B alpha thereby preventing NF-kappa B activation. These results identify a novel negative feedback mechanism whereby NO down-regulates iNOS gene expression.

A Clinical Study of Apatite- and Wollastonite-containing Glass-ceramics as a bone prosthesis / 대한정형외과학회잡지

PURPOSE: To investigate in vivo reaction of newly developed glass-ceramic, we inserted an iliac crest prosthesis using apatite- and wollastonite-containing glass-ceramic. The efficacy and side effect of this prosthesis, if any, were studied clinically and radiologically. MATERIALS AND METHODS: A full-thickness bone graft of the iliac crest was made in 20 patients who needed revisional surgery for THR loosening. Different sized blocks (ranging from 3 cm to 7 cm in length) of bioactive glass-ceramic prosthesis were made and implanted in a complete and large bony deficiency of the iliac crest. The postoperative follow-up period ranged from 8 to 13 months (average 11 months). Following the operations, clinical and radiological examinations were performed postoperatively at 2 weeks, 3, 6 and 12 months. RESULTS: Clinically, no foreign body reactions, including swelling and irritation, were noted. Radiologically, no displacement and no breakdown of the iliac prostheses were seen 11 months after surgery and the radiolucent line between the prosthesis and the iliac bone gradually disappeared with time in all cases. CONCLUSIONS: The apatite- and wollastonite-containing glass-ceramic supplementation for the iliac bony defect was successful experimentally and this glass-ceramic, which contains sufficient mechanical strength and can strongly bond with host bone, may be a promising prosthesis in the repair of large bone defect.

Cementless Acetabular Revision using Morselized Bone Grafts and Screw Fixed Hemispherical Cup / 대한정형외과학회잡지

The purpose of this study is to evaiuate the results of the reconstruction of acetabular bone defect with morselized bone graft and screw fixed hemispherical cup in revision of failed acetabular cup. Thirty four revisions of an acetabular component that had been performed in 34 patients between 1988 and 1993 at SNUH, and had followed more than four years were included in this study. The revised acetabulum was evaluated clinically by Harris hip score and radiologically by evaluating the osseous union, incorporation and resorption of graft, the amount of migration and cup angle change of revised components and periacetabular radiolucency. The mean Harris hip score was improved 52 to 84. All of the bone grafts united by 6.4 months and incorporated by 13.1 months. The graft bone resorption less than onefourth of the initial graft thickness was 91.2% (31 cases). There was no significant difference between pure allograft and allograft mixed with autograft in clinical and radiological results. Of 34 cases, 2 cases (5.9%) required rerevision of acetabulum for aseptic loosening. The two complications, postoperative infection and trochanteric bursitis were managed successfully with conservative methods. The results of the present study confirm the success of revision of the acetabulum with use of a hemispherical component stabilized with multiple small screws and morselized bone grafts filling bone defects.

The Clinical Results of Primary Cementless Total Hip Arthroplasties Using Omnifit Microstructured System: A Five-Year Clinical Follow-Up Study and Roentgenographic Analysis / 대한정형외과학회잡지

We reviewed 64 primary cementless porous-coated total hip arthroplasties using Omnifit Microstructured system (Osteonics, Allendale, New Jersey, U.S.A.). They were followed up for an average of 6 years (range, 5 years to 7 years and 11 months). The average Harris score was improved from 60.8 preoperatively to 86.2 postoperatively. The results were excellent in 3i cases(48.4%), good in 22 cases(34.4%), fair in 7 cases(I0.9%) and poor in 4 cases(6.3%). According to the last t'ollow-up radiologic findings, 61 cases(95.3%) were considered to he stable bony fixation and 3 cases(4.7%) to he stahle fibrous fixation. Neither unstahle fixation nor loosening of component was ohserved. But osteolysis was occured in 32 cases(50.0%) around prosthetic stem and in l6 cases(25.0%) around prosthetic cup. The mean linear wear of polyethylene insert was 1.46mm(range, 0.1 mm to 5.83mm). the linear wear rate was 0.23mm/year (range, 0.02mm/year to 0.81mm/year) and the excessive wear more than 2mm was ohserved in 15 cases. Reoperation was required in 18 cases(28. l%) after followup of 6 years (range, 4 years and 3 months to 7 years and 2 months); 11 had been reoperated and 7 were awaiting reoperation. The causes of reoperation were osteolysis and excessive polyethylene wear (more than 2mm) in 15 cases and osteolysis only in 3 cases. The result of primary cementless porous-coated total hip arthroplasties using Omnifit Microstructured system was acceptahle up to 5 years, but then increasing reoperation appeared to he due to polyethylene wear and osteolysis. Therefore, the routine follow-up of cementless porous-coated total hip arthroplasties is essential, especially after 5 years in order to detect and manage such prohlems early. And the modification in materials suhstituting metal-on-polyethylene articulation is required to reduce them.

Effect of Ascorbic Acid on Experimental Retinal Vein Occlusion

The retinal vein occlusion is one of the most common vision-threatening retinal diseases, and both the hemi-central and central retinal vein occlusion might induce severe visual loss. There have been many studies on the role of abnormally produced oxygen free radicals and excitatory amino acids in the mechanism of ischemic retinal injury. Many free radical scavengers, such as superoxide dismutase (SOD), catalase, and EGB 761 were reported to reduce the extent of ischemic retinal injury in animal experiments. Ascorbic acid is also a well-known free radical scavenger, but its in vivo therapeutic effects on retinal ischemia has not been studied, yet. We induced experimental retinal vein occlusion in 48 albino rat eyes; half of major veins in 24 eyes (group A) and total veins in 24 eyes (group B), with rose bengal dye injection followed by argon-green laser photocoagulation. The occlusion of veins was confirmed with fluorescein angiography. We injected ascorbic acid intraperitoneally just after venous occlusion in 12 eyes for each group. Rats were sacrificed after I week (group A) or 2 weeks (group B) following experiment and histological examination was done. In both groups, inner retina was less damaged than outer retina. The density of retinal ganglion cells was reduced to a less degree in eyes of rats treated with ascorbic acid in group A(P=0.0318). These data support the idea that the reactive free adicals are involved in the mechanism of ischemic retinal injury and thus the ascorbic acid may attenuate the ischemic retinal damage.

Experimental Retianl Vein Occlusion in Albino Rats

The retinal vein occlusion is one of the most common, vision-threatening retinal diseases, and the establishment of animal model in rats will be of great help for further study. We occluded retinal veins with rose bengal dye injection followed by argon green laser photocoagulation in albino rats and confirmed the occlusion of veins with fluorescein angiography one hour after photocoagulation. We occluded half of an all of major retinal veins in 12 eyes, respectively. After 1-2 weeks of follow-up, histologic examinations were done. Eyes which underwent occlusion of all major retinal veins showed severe retinal atrophy and preretinal neovas-cularization developed in two eyes. Eyes which underwent occlusion of half of retinal veins showed relatively less damage and the number of retinal ganglion cells was significantly reduced in occluded area than that in control area (P=0.0033), which might represent the ischemic damage of inner retina. We expect that it will be possible to establish an animal model of retinal vein occlusion in albino rats using this method.

Experimental Branch Retinal Vein Occlusion in Albino Rats

The retinal vein occlusion is one of the most common retinal diseases, and the establishment of animal model in rats will be a great help for further study. We occluded branch retinal veins with rose bengal dye injection followed by argon-green laser photocoagulation in albino rats. Retinal vein occlusion was maintained over 1 day in 35 eyes out of 47, maximally over 5 days. Retinal tissue damage was confined to the photocoagulated areas in most eyes and the loss of ganglion cells began when the occlusion persisted over 1 day. If the reproducibility is further increased, this will be a good animal model of retinal vein occlusion in albino rats.

Allograft transplantation in the segmental defect of the long bone (7 cases report) / 대한정형외과학회잡지

No abstract available.

Implantation of Intraocular Lenses in Traumatic Cataract

We implanted intraocular lenses in 41 eyes of 41 patients with traumatic cataract without associated retinal injury. All the enrolled patients had sustained injury visited the Incheon Gil Hospital between August 1988 and June 1992. We analyzed age and sex distribution, mode and site of injuries, associated injuries, postoperative complications, methods of operation, final visual results and causes of decreased vision. Nineteen patients(46.4%) achieved final visual acuity of 0.5 or better, 11 patients(26.8%) between 0.1 and 0.5, and the remaining 11(26.8%) below 0.1. Major visual prognostic factors were associated ocular injuries, the state of the posterior lens capule, intraoperative and early postoperative complications. The interval between the first and second operation had little effect on the final vision.

A Clinical Study of Traumatic Hyphema

Traumatic hyphema accounts for about 6.7% of ocular trauma and its visual threatening associated ocular injuries are commotio retinae, retinal detachment, macular hole. cataract and rebleeding. The authors reviewed the medical records of 98 patients (98 eyes) having been admitted to the Joongang Gil Hospital between March 1989 and February 1991 with the diagnosis of nonperforating traumatic hyphema. Prospective study was performed as to the effect of epsilon-aminocaproic acid (EACA) in the clearance time of blood clot in the anterior chamber and the frequency of rebleeding. The avlrage clearance time of blood clot was significantly longer in the EACA treated group (5.8 days) than in the control group (3.5 days)(t-Test P0.05).

A Case of Herpes Zoster Ophthalmicus Complicated by Abducens Palsy

The complications of herpes zoster ophthalmicus vary greatly among different patients. The major portion of the complications fall under four types; (1) keratitis, (2) iridocyclitis, (3) muscular palsies, and (4) optic neuritis. We have experienced a case of herpes zoster ophthalmicus complicated by abducens palsy, sectorial paralysis of iris sphincter, iritis, and transient increase of intraocular pressure. The case was reviewed and the pathogenesis of the complications were discus sed.

Electroretinographic Change after Intravitreal Silicone Oil Injection in Rabbit

Effect of silicone oil in vitreous cavity of the rabbit was studied with electroretinogram. Pars plana vitrectomy was performed bilaterally in nine white rabbits, and they were divided into 3 groups. 1.6~1.7 cc of silicone oil was injected in right eye in 1st group, 0.8 cc of silicone oil was injected in right eye in 2 nd group, and 0.8~1.0 cc of silicone oil was injected in right eye after retinal tear was made in 3 rd group. Left eye in each group was used as a control. Photopic and scotopic electroretinographic studies were performed in both eye of rabbits preoperatively and postoperatively 2 days, 1 week, 2 weeks, 3 weeks, and 4 weeks. In each group, a and b-wave amplitude was decreased in silicone oil injected eye compared to control eye at postoperative 2 days, and was increased to normal amplitude at postoperative 4 weeks in both photopic and scotopic electroretinograms. Implicit time of a and b-wave was not affected in each group. Above results suggest that rabbit electroretinogram is not affected by intravitreal silicone oil until postoperative 4 weeks.

Normal Growth in the Genitalia of Korean Male Children

An accurate evaluation of the size of the genitalia and its function is mandatory in judging abnormal growth of external genitalia from birth to adolescence as well as adulthood. This study was carried out to establish the standard values of penile and testicular sizes for normal Korean boys. Nine hundred and fifty-four Korean boys from birth to 15 years of age were subjected. The genital measurements were performed on the length and circumference of the flaccid and erect penis, and the length, width and depth of testis. The length of the penis was measured on the dorsal surface from the pubopenile skin junction to the tip of the glans with a sliding rule, and the circumference with a measuring tape. A sliding caliper was used for measurement of testis. Each testicular volume was calculated using the formula: V = 0.71 X L X W X D, where V is volume; L, length; W, width and D, depth. The mean of the two testes was taken as individual's testicular volume. The results are as follows. 1. The means, standard deviations and 95 percent confidence intervals of flaccid and erect penile length and circumference and testicular volume according to age were obtained. Except a slight increase in the penile length in the first four to five years the sizes of penis and testis did not change appreciably until prepubescence. With the onset of pubescence, there was a rapid spurt in penile size and testicular volume. 2. Marked differences in the erect penile length and circumference and testicular volume were observed between the two groups of the same ages with or without pubic hair. 3. A diagram of longitudinal median sections of testes in actual size arranged by age was obtained. 4. The right testis was larger than the left in 65.9%, the right testis was smaller than the left in 27.3% and the right and left testes were equal in 6.8% of boys studied. 5. Correlation coefficients(r) between height and erect penile length and circumference as well as testicular volume revealed 0.76, 0.74, 0.56, respectively. Correlation coefficients with weight were 0.75, 0.73, 0.55, respectively.