Primary herpes simplex iridocyclitis with iris atrophy.
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Adult↗
Biomedical subjects
T S Chang
Publications and source records attributed to T S Chang.
Ocular clinicopathologic study of the mitochondrial encephalomyopathy overlap syndromes.
Recent advances in molecular genetics have led to a better understanding of mitochondrially inherited diseases. Mitochondrial encephalomyopathy overlap syndrome is one such group of diseases in which ocular abnormalities are frequently manifest. The authors describe the clinical, molecular genetic, and pathologic findings of two patients with the mitochondrial encephalomyopathy overlap syndrome. The patients shared a similar clinical course with features overlapping the three traditionally distinct clinical phenotypes (the Kearns-Sayre syndrome; the syndrome of mitochondrial encephalopathy, lactic acidosis, and stroke [MELAS], and the syndrome of myoclonus, epilepsy, and ragged red fibers [MERRF]). The patients had identical mitochondrial DNA mutations (at nucleotide position 3243) and had similar ultrastructural abnormalities, including abundant enlarged mitochondria with "whorled" and "tubular" cristae. These abnormal mitochondria appeared to be preferentially distributed in cells with high metabolic activity (retinal pigment epithelium, corneal endothelium, and extraocular muscles).
Abnormalities, Multiple↗
Immunohistochemical localization of nitric oxide synthase in the autonomic innervation of the human penis.
An improved understanding of the physiology of penile erection has resulted from recent evidence that implicates nitric oxide as the principal mediator of erectile function. Previously, the neuroanatomy of erection in man was established with descriptions of the autonomic innervation of the pelvic organs and external genitalia. The basis upon which novel physiological concepts of erection relate to earlier neuroanatomical principles remains to be determined. In the present study these relationships were explored with nitric oxide synthase immunohistochemistry and reduced nicotinamide adenine dinucleotide phosphate (NADPH) diaphorase histochemistry of select pelvic tissue specimens obtained from 4 men (3 at radical prostatectomy and 1 at autopsy). Nitric oxide synthase, the enzyme that catalyzes nitric oxide production, was identified in discrete neuronal locations, including the pelvic plexus, cavernous nerves and their terminal endings within the corporeal erectile tissue, branches of the dorsal penile nerves and nerve plexuses in the adventitia of the deep cavernous arteries. This distribution of nitric oxide synthase-containing nerves suggests that nitric oxide neuronally modulates local vascular smooth musculature of the penis. On this basis, nitric oxide is identified as a neuronal mediator of penile erection in man.
Aged↗
Microsurgical replantation of the avulsed scalp: report of six cases.
This article reports the successful microsurgical replantation of six scalps avulsed for over 3 to 11 hr, after trauma and before repair, including five total and one partial avulsion. The authors believe that one key to successful replantation is effective vessel anastomoses. In the reported series, three scalps were reconstructed with two superficial temporal vessels and in five cases, with a 1:1 ratio between arteries and veins. The partially avulsed scalp was replanted successfully with only one artery and one vein. The management of postoperative complications is discussed.
Accidents, Occupational↗
Nongynecologic applications of transvaginal sonography.
Transvaginal sonography has become an invaluable technique for examining the uterus and adnexa, primarily because it provides better spatial resolution than transabdominal sonography does. This characteristic also makes it useful for evaluating the nongynecologic structures in the pelvis. As many of these structures are imaged incidentally during gynecologic transvaginal sonography, familiarity with their normal and abnormal appearances is important. With minor modifications in technique, targeted studies of these structures are easily performed. We illustrate the technique used, normal anatomy seen, and abnormalities commonly encountered in transvaginal sonography of nongynecologic pelvic structures.
Blood Vessels↗
[Successful replantation of scalp avulsion in the parietal area with vascular microanastomosis. Apropos of a clinical case].
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Adult↗
Congenital trichomegaly, pigmentary degeneration of the retina and growth retardation (Oliver-McFarlane syndrome): 28-year follow-up of the first reported case.
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Adult↗
Nitric oxide: a physiologic mediator of penile erection.
Nitric oxide (NO) is a cytotoxic agent of macrophages, a messenger molecule of neurons, and a vasodilator produced by endothelial cells. NO synthase, the synthetic enzyme for NO, was localized to rat penile neurons innervating the corpora cavernosa and to neuronal plexuses in the adventitial layer of penile arteries. Small doses of NO synthase inhibitors abolished electrophysiologically induced penile erections. These results establish NO as a physiologic mediator of erectile function.
Amino Acid Oxidoreductases↗
Trans-scleral neodymium: YAG retinal photocoagulation in rabbit eyes.
To assess the ability of trans-scleral application of the continuous-wave neodymium: YAG laser to produce retinal ablation with reproducible chorioretinal scars, retinal photocoagulation with the YAG laser was done in four Dutch-belted rabbits (eight eyes). Sharply defined, reproducible lesions were produced that were identical to those found following conventional treatment with the argon laser. At 0.2 J there was destruction of the outer retinal layers with sparing of the inner retinal layers. At 3.0 J full-thickness retinal reorganization was noted; however, even at this energy setting there was minimal histologic evidence of scleral damage. Focused laser energy produced distinctly more retinal destruction and obliteration of the retinal pigment epithelium than unfocused energy. The results suggest that trans-scleral photocoagulation with the YAG laser may be possible and would be particularly applicable in situations in which media opacities preclude visualization of the retina.
Animals↗
Priority in the use of the forearm free flap in one-stage phalloplasty.
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Follow-Up Studies↗
Ultrasonography in the emergency setting.
US is the imaging modality of choice in many situations encountered in the Emergency Department. It is particularly useful in evaluating renal colic, pain or vaginal bleeding in the pregnant patient, and pelvic pain in the nonpregnant woman; and in diagnosing gallbladder disease, appendicitis, proximal lower extremity DVT, and pericardial effusion. The information presented in each section, including sonographic findings and the role of US, should be helpful in choosing the most appropriate test in the evaluation process.
Aorta, Abdominal↗
Antibiotics: potential hazards to male fertility.
Individual agents within each of the major classes of antibiotics have been shown to have significant adverse effects on spermatogenesis or spermatozoal function in mammals. For humans, infertility or significant alterations in semen parameters have been well documented for the nitrofurans and for patients on sulfasalazine. Other commonly used antibiotics, such as minocycline, have been shown to be toxic to sperm at any concentration. Until further information is available, clinicians must keep in mind that treatment with antibiotics may adversely affect the fertility potential of men. It is possible that some classes of antibiotic agents, such as the penicillins or the quinolones, may have minimal effects on male fertility and maintain the clinical efficacy for patients requiring long-term antibiotic suppressive therapy. Further investigation is needed into the relative toxicity of antibiotics and the mechanisms by which antibiotics affect spermatogenesis and spermatozoal function. A background of the current state of knowledge regarding the adverse effects of antibiotics on male fertility is presented in this review.
Animals↗
Fatty liver. Chemical shift phase-difference and suppression magnetic resonance imaging techniques in animals, phantoms, and humans.
In vitro animal and human models were used to evaluate the potential of chemical shift magnetic resonance imaging (MRI) for assessing fatty liver. Phantoms of varying fat content were created from mayonnaise-agar preparations. Fatty liver was induced in eight rats by feeding them ethanol for three to six weeks (36% of total calories), whereas eight control rats were fed a normal diet. T1-weighted in-phase and opposed-phase MR images were obtained of the phantoms animals, and 28 human subjects. Additional images obtained in animals included long TR images with in-phase and opposed-phase technique, and hybrid chemical shift water and fat suppression. The rats were killed and histologic status was graded blindly by a hepatopathologist as normal, mild, moderate, or severe fatty change, for correlation with MR grading. Quantitative analysis of MR images included fat signal fraction for animals, and relative signal decrease between in-phase and opposed-phase images for phantom and human data. Phantom in-phase signal increased linearly with respect to fat content, whereas opposed-phase signal decreased linearly. MRI and histologic grading of rat livers were highly correlated, especially when based on water suppression images (r = 0.91, P = .0001). Opposed-phase images were also highly correlated, while fat suppression images were less effective. There was no overlap between MR-derived fat fractions for control (2.6%-5.7%) versus ethanol-fed rats (7.7%-17.9%, P = .0002). Human liver considered to be fatty by visual inspection (n = 8) had higher relative signal decrease than nonfatty liver (n = 22) (P less than .001). Phantom, animal, and human data demonstrate that comparison of T1-weighted in-phase and opposed-phase images is both practical and sensitive in the detection and grading of fatty liver.
Adult↗
Ablation of the inferior mesenteric plexus in the rat: alteration of sperm storage in the epididymis and vas deferens.
The involvement of the sympathetic nervous system in the transport and storage of spermatozoa in the male reproductive tract was examined by surgically ablating the inferior mesenteric plexus (IMP). One to eight weeks after ablation of the IMP, epididymal weight and the total number of spermatozoa present in the cauda epididymidis were significantly greater in IMP-ablated rats than in sham-operated rats. By contrast, the number of spermatozoa present in the initial segment of the vas deferens was significantly greater than in sham operated controls one week after IMP ablation but returned to control levels at two, four, six and eight weeks. Throughout the experiment, no differences were observed between IMP-ablated and control rats in the percentage of motile cauda epididymal spermatozoa, testicular weight, testicular sperm number or serum testosterone. These data demonstrate that the sympathetic nervous system differentially regulates sperm transport and storage in the male reproductive tract and suggest that the IMP may influence the epididymal maturation of spermatozoa.
Animals↗
Reduction of epididymal sperm motility after ablation of the inferior mesenteric plexus in the rat.
Surgical ablation of the inferior mesenteric plexus in the rat results in an excessive accumulation of sperm within the cauda epididymidis. The present study examined the effect of ablation of the inferior mesenteric plexus on the motility of cauda epididymal spermatozoa. One to 8 weeks after ablation of the inferior mesenteric plexus, sperm curvilinear and straight line swimming velocities were reduced significantly compared with sperm curvilinear and straight line swimming velocities from sham-operated controls. Sperm swimming linearity also changed significantly versus controls after inferior mesenteric plexus ablation. Additional experiments using a vasectomy model suggested that the reductions in sperm curvilinear and straight swimming velocities after inferior mesenteric plexus ablation were not primarily the result of tubal obstruction. These data suggest that the sympathetic nervous system may influence epididymal sperm function.
Analysis of Variance↗
Binding and activation of plasminogen on immobilized immunoglobulin G. Identification of the plasmin-derived Fab as the plasminogen-binding fragment.
We have found that tissue plasminogen activator catalyzes the binding of plasminogen (Pg) to immunoglobulin G (IgG) immobilized on a surface. This enhancement is due to the formation of plasmin, since plasmin treatment of immobilized IgG produced a 20-fold increase in Pg binding. Pg binding is lysine site dependent and reversible. The augmentation of Pg binding by plasmin is specific as other proteases produced significantly less or no effect. Immobilized plasmin-treated IgG also specifically binds Pg in plasma. IgG-immobilized Pg is activated by tissue plasminogen activator, and a significant portion of the plasmin formed remains bound to the IgG. The Pg reactive species in a plasmin-treated IgG digest was identified as the Fab fragment by chromatography utilizing the immobilized high affinity lysine-binding site of plasminogen. Specificity of the interaction was further demonstrated by immunoblot-ligand analysis which demonstrated that the plasmin-derived Fab fragment bound Pg whereas papain-derived Fab or plasmin-derived Fc fragments did not. These data suggest that Pg binds to the new COOH-terminal lysine residue of the plasmin-derived Fab. Pg also binds to an immobilized immune complex following plasmin treatment. These findings indicate that surface-bound IgG localizes plasminogen thus extending the spectrum of activity of the plasmin system to immunologic reactions.
Enzyme Activation↗
Characterization and localization of in vivo phospholipid methylation in the hamster testis.
Although previous studies have demonstrated that phospholipid methylation occurs in the testis and may be involved in Leydig cell function, phospholipid methylation in spermatogenic cells has not been characterized. In this study we describe the occurrence, time course, and localization of phospholipid methylation in the hamster testis following intratesticular injection of radioactive methyl precursor. Adult and pubertal (seven day old) hamsters were injected intratesticularly with [3H-methyl]-methionine and sacrificed 10 min. to 31 hours thereafter. The testes were then removed and homogenized or dispersed into cell suspensions. Spermatogenic cell and Leydig cell enriched preparations were isolated from the dispersed cell preparations using elutriation and Percoll gradient centrifugation and assayed for methylated phospholipids and proteins. These experiments demonstrated that 1) phospholipid methylation occurs in the hamster testis at a level seven-fold greater than protein methylation, 2) the incorporation of radioactivity associated with phospholipid methylation is progressive over time, and 3) in vivo, spermatogenic cell preparations enriched with pachytene spermatocytes have an almost four-fold higher level of measurable phospholipid methylation when compared to whole testis preparations. Taken together, these results suggest that phospholipid methylation may play an important stage-specific role in spermatogenesis.
Animals↗
Clinical application of the free scapular fascial flap.
Seven free scapular fascial flaps with a skin graft on top were used to cover soft tissue defects of the hand and foot in 6 patients during the past two years. The size of the flap ranged from 7 x 8 cm to 8 x 12 cm. All flaps survived well, but one had partial loss as a result of infection. The advantages, disadvantages, indications, and important technical points of the surgery are discussed.
Adolescent↗