Repeated Treatment Protocols for Melasma and Acquired Dermal Melanocytosis

BACKGROUND AND OBJECTIVE: Melasma and acquired dermal melanocytosis (ADM; acquired bilateral nevus of Ota-like macules) are both seen most commonly symmetrically on the face of women with darker skin and are also known as difficult conditions to treat. METHODS: Our topical bleaching protocol with 0.1 to 0.4% tretinoin gel and 5% hydroquinone was performed repeatedly (1-3 times) for melasma (n=163), and a combination treatment with topical bleaching and Q-switched ruby (QSR) laser was performed repeatedly (1-3 times) for ADM (n=62). RESULTS: There is a significant correlation between clinical results (clearance of pigmentation) and the number of sessions in both melasma (p=.019) and ADM (p<.0001). CONCLUSION: The repeated treatment protocol for melasma and ADM showed successful clinical results compared with conventional ones, and they may be applied to other pigment conditions. It may be better that epidermal and dermal pigmentations are treated separately, especially in dark-skinned people who are more likely to suffer postinflammatory hyperpigmentation after inflammation-inducing therapies.     

Varicocele rupture due to sexual intercourse

Varicocele rupture was diagnosed in a 23-year-old man who presented with swelling and pain in the left scrotum after sexual intercourse. Color Doppler ultrasonography revealed blood flowing into the space surrounding the left testis, a hematoma and reflux of blood in the left spermatic vein. Varicocele rupture is a very rare condition and there have been only five reported cases.     

Effects of Acute Ischemia on Anisotropic Conduction in Canine Ventricular Muscle

The effects of acute ischemia on conduction velocities in the longitudinal (θ_L)and transverse (θ_T)fiber axis were determined from epicardiai activafion patterns, recorded with 48 bipolar electrodes (piaque eiectrode, 25 × 35 mm) on the left anterior ventricuiar wail of eight dogs and the posterior wall of seven dogs. During left ventricuJar stimulation (cycle length = 300 msec)in the center of the piaque electrode, θ_L, θ_T, and the ratio of longitudinai to transverse conduction velocities (θ_L/t)were measured before and 2 to 5 minutes after occiusion of the left anterior descending coronary artery or the left circumflex coronary artery. During the control state θ_Lwas greater thon θ_Tdemonstrating anisotropic properties of cardiac muscle, not only in the anterior but also in the posterior wail. During acute ischemia θ_L and θ_Twere decreased from the control value and θ_T was decreased by a greater extent than θ_L, resuiting in an increase in θ_L/Tfrom 1.83 ± 0.31 (mean ± SD)to 2.19 ± 0.36 in the anterior wall and from 1.58 ± 0.17 to 1.92 ± 0.28 in the posterior wall. During ventricuiar fibriiiation some lines of conduction block were parallel to the long axis of epicardial muscie fiber bundle and the others were perpendicular. In conclusion, acute ischemia increased anisotropic conduction (Bl/t) in the epicardial ventricular muscle mainly due to greater reduction in θ_T, in the anterior and the posterior wall. This augmented anisotropic ventricuiar conduction may have some relation to the initiation of ventricular fibrillation during acute ischemia.     

Shortcut Link Between the Fast and Slow Pathways and the Mechanism of Cure in Atrioventricular Nodal Reentrant Tachycardia by Catheter Ablation

The mechanism of cure in AV nodal reentrant tachycardia (AVNRT) by catheter ablation has not been fully clarified. We hypothesized that disruption of a shortcut link between the fast and slow pathways is responsible for the elimination of tachycardia. Results: AVNRT was eliminated in 20 patients by catheter ablation. In five patients (25%; group 1) slow pathway conduction disappeared 1 week after ablation. In six patients (30%; group II), the effective refractory period of the slow pathway was prolonged by more than 50 ms (212 ± 81 ms vs 340 ± 81 ms; P < 0.05). In the remaining nine patients (45%; group III), there was no change in the refractory period (270 ± 65 ms vs 273 ± 74 ms), although tachycardia was not inducible. A shortcut link between the fast and slow pathways was examined by comparing the A-H intervals over the slow pathway during the tachycardia and during atrial pacing at the tachycardia cycle length. Prior to ablation, a shortcut link was assumed in 1 of group I patients, 2 of group II patients, and 8 of group III patients. Of the 9 patients in whom the slow pathway was not impaired after ablation (group III), 8 patients were found to have a shortcut link, while 8 of 11 patients with impairment of the slow pathway after ablation (groups I and II) had no shortcut link between the fast and slow pathways (P < 0.05). Conclusion: In patients with a shortcut link between the fast and slow pathways, slow pathway conduction itself does not need to be impaired to eliminate the AVNRT, whereas in patients without this shortcut link, slow pathway conduction must be impaired.     

Myeloid differentiation is impaired in transgenic mice with targeted expression of a dominant negative form of retinoid X receptor β

To investigate the in vivo function of retinoid X receptor (RXR) on myelopoiesis, we generated transgenic (Tg) mice with targeted expression of a dominant negative form of RXR β in myeloid cells. In these Tg mice the transgene is expected to suppress the function of heterodimeric receptors composed of RXR and its counterparts, such as retinoic acid receptor. Out of 12 mice analysed, one Tg mouse exhibited a severe maturation arrest at the promyelocytic stage. Three other Tg mice showed a mild inhibition of myeloid differentiation, which was further augmented when mice were treated with 5-fluorouracil (5-FU). Furthermore, four Tg mice showed impaired myeloid differentiation in response to the treatment by 5-FU or granulocyte-colony stimulating factor (G-CSF), although they exhibited apparently normal myelopoiesis in the untreated state. The phenotype of Tg mice observed after G-CSF treatment correlated with the expression level of the transgene, although the correlation was not found in untreated mice. These results indicated that myeloid differentiation is perturbed in the Tg mice by the dominant negative effect of the transgenic RXR, indicating that RXR plays a role in myelopoiesis.     

Selected Slow Pathway Ablation in a Patient with Corrected Transposition of the Great Arteries and Atrioventricular Nodal Reentrant Tachycardia

AVNRT in Corrected TGA. We report the first known case of AV nodal reentrant tachycardia (AVNRT) associated with a corrected transposition of the great arteries to be treated successfully by ablation of the slow pathway. Triple AV nodal pathways were observed in the anterograde direction and two types of AVNRT were induced. Input of the fast pathway to the AV node was located at the anterior portion of the left-sided A V annulus, while the input of the intermediate and slow pathways was located at the anteroseptal portion of the right-sided AV annulus. Radiofrequency energy ablation at the right anteroseptal site eliminated the intermediate and slow pathways.