Geographic variation in mimetic precision among different species of coral snake mimics.

Batesian mimicry is widespread, but whether and why different species of mimics vary geographically in resemblance to their model is unclear. We characterized geographic variation in mimetic precision among four Batesian mimics of coral snakes. Each mimic occurs where its model is abundant (i.e. in 'deep sympatry'), rare (i.e. at the sympatry/allopatry boundary or 'edge sympatry') and absent (i.e. in allopatry). Geographic variation in mimetic precision was qualitatively different among these mimics. In one mimic, the most precise individuals occurred in edge sympatry; in another, they occurred in deep sympatry; in the third, they occurred in allopatry; and in the fourth, precise mimics were not concentrated anywhere throughout their range. Mimicry was less precise in allopatry than in sympatry in only two mimics. We present several nonmutually exclusive hypotheses for these patterns. Generally, examining geographic variation in mimetic precision - within and among different mimics - offers novel insights into the causes and consequences of mimicry.

A case of Klippel-Trenaunay syndrome involving only upper limbs.

The case of a 14-year-old girl suffering from Klippel-Trenaunay syndrome associated with multiple port-wine stain type vascular anomalies and varicose veins involving upper limbs is described. Finger deformations are common in Klippel-Trenaunay syndrome. In our patient, striking hypertrophy of soft tissues and overgrowth of bones were observed on both forearms and finger deformations were observed particularly on right thumb and index finger. Although lower limb involvement is very common amongst the patients with Klippel-Trenaunay syndrome, in our patient involvement of the lower limbs was not observed.

Association of insertion/deletion polymorphism of the angiotensin-converting enzyme gene with angio-oedema accompanying chronic urticaria but not chronic urticaria without angio-oedema or the autologous serum skin test response.

BACKGROUND: Chronic urticaria is defined as the daily or almost daily occurrence of weals for more than 6 weeks. The underlying pathophysiology is reported to be mast cell activation, with release of mast cell mediators, predominantly histamine. Substance P is a neuropeptide and has the capacity to provoke histamine release from skin mast cells. Angiotensin-converting enzyme (ACE), widely expressed in skin, is one of the major peptidase for the degradation of substance P. An insertion/deletion polymorphism (I/D) in the ACE gene has been reported to be related to the levels of enzyme. OBJECTIVE: An increase in substance P levels due to a polymorphism in ACE gene might be related to the pathology. Thus, we aimed to investigate whether there is an association between ACE I/D polymorphism and chronic ordinary urticaria. METHODS: Ninety-five patients with chronic ordinary urticaria were recruited and divided into two groups according to autologous serum skin test status and accompanying angio-oedema. One hundred and sixty-one healthy subjects were enrolled as control group. All participants were genotyped for I/D polymorphism in intron 16 of the ACE gene by polymerase chain reaction. RESULTS: A statistically significant association was not found between ACE I/D polymorphism and chronic ordinary urticaria. Further analyses of chronic ordinary urticaria patients showed that ACE I/D polymorphism was not associated with autologous serum skin test status of patients. However, the frequencies of II genotype and I allele were statistically significantly higher in chronic ordinary urticaria patients with accompanying angio-oedema with regard to angio-oedema-negative patients (II genotype: 24% vs. 9%, P = 0.0002; I allele: 58% vs. 27%, P = 0.0001) and control group (II genotype: 24% vs. 19%, P = 0.01; I allele: 58% vs. 41%, P = 0.03). CONCLUSION: The results of this study suggest no evidence of an association between ACE I/D polymorphism and risk of developing chronic ordinary urticaria. However, it can be a contributing factor to susceptibility of angio-oedema in chronic ordinary urticaria.

Detection of metastases in patients with cutaneous melanoma using FDG-PET/CT.

This study aimed to detect metastases in patients with stage III or IV cutaneous melanoma by (18)F-fluorodeoxyglucose positron emission tomography combined with computed tomography (FDG-PET/CT). Thirty-nine patients with clinically evident stage III or IV melanoma underwent whole-body FDG-PET/CT scans for metastatic disease and these results were compared with those of biopsy. Scans for 38 of the patients were evaluated; one patient's scan could not be evaluated. There were 11 true-positive, two false-positive, 24 true-negative and one false-negative scans for the detection of melanoma metastases, with sensitivity 91%, specificity 92%, accuracy 92%, and positive and negative predictive values 84% and 96%, respectively. False-positive FDG-PET/CT scans were due to sarcoidosis in the lung and infected cyst in the liver. It is concluded that FDG-PET/CT scanning has high sensitivity and specificity for detecting stage III or IV metastatic melanoma.

The effects of anastrozole on neonatal rat skin.

BACKGROUND: Anastrozole is a third-generation nonsteroidal aromatase inhibitor which is used in the treatment of breast cancers. Anastrozole has also been used in the treatment of dermatomyositis skin eruptions but its direct effects on skin have not been well documented. OBJECTIVE: To study the effects of anastrozole administration on neonatal rat skin. METHODS: Forty Sprague-Dawley female newborn rats were separated into two control groups and two experimental groups (n = 10). One day after birth the control group of newborn rats were given daily 0.02 ml saline subcutaneously for a period of 15 days. The first experimental group of rats were treated with 0.05 mg/100g/day anastrozole subcutaneously for 15 days whereas the second experimental group of rats were given 0.25 mg/100g/day anastrozole subcutaneously for 15 days. Histopathological assessments were made and compared with the control groups. RESULTS: Increased keratinization, strippling, hypertrophic epidermal cells and disorganization of the epidermal cells were observed in the first experimental group. In the second experimental group in addition to these pathologic findings acantholysis was observed. CONCLUSION: The administration of anastrazole in newborn rats showed considerable harmful effects.

The Laugier-Hunziker syndrome.

Laugier-Hunziker syndrome is a rare, acquired, benign hyperpigmentation of the lips, oral mucosa and nails. Although it is a benign disorder, other pigmentary disorders affecting the oral mucosa and nails must be considered in the different diagnosis. We presented a case of Laugier-Hunziker syndrome, showed clinical and histopathologic features of the disease.

Biweekly serial glycolic acid peels vs. long-term daily use of topical low-strength glycolic acid in the treatment of atrophic acne scars.

BACKGROUND AND OBJECTIVE: Treatment of atrophic acne scars is difficult and generally unsatisfactory. Although many clinical studies have been performed to investigate the efficacy of glycolic acid in the treatment of acne vulgaris, to the best of our knowledge no placebo-controlled study has been carried out to ascertain the effect of glycolic acid on atrophic postacne scars. DESIGN: A single, blind, placebo-controlled, randomized comparative clinical study was conducted in 58 women with atrophic acne scars. The subjects were randomly divided into three study groups. Glycolic acid peels with 20%, 35%, 50%, and 70% concentrations were applied serially at 2-week intervals to 23 patients in Group A. Twenty patients in Group B used a 15% glycolic acid cream once or twice daily for a period of 24 weeks. The remaining 15 patients in Group C applied a placebo cream twice daily during the same period. RESULTS: The differences between the results in the different groups were statistically significant at week 24 (P<0.001). Home application of low-strength glycolic acid was better tolerated and had less side-effects than glycolic acid peels; however, repeated short-contact 70% glycolic acid peels provided superior results compared with the maintenance regimen (P<0.05), and apparently good responses were observed only in the peel group (P<0.01). CONCLUSIONS: Glycolic acid peeling is an effective modality for the treatment of atrophic acne scars, but repetitive peels (at least six times) with 70% concentration are necessary to obtain evident improvement. Long-term daily use of low-strength products may also have some useful effects on scars and may be recommended for patients who cannot tolerate the peeling procedure.

Participation of the melanocortin-1 receptor in the UV control of pigmentation.

The cloning of the melanocortin-1 receptor (MC1R) gene from human melanocytes and the demonstration that these cells respond to the melanocortins alpha-melanocyte stimulating hormone (alpha-MSH) and adrenocorticotropic hormone (ACTH) with increased proliferation and melanogenesis have renewed the interest in investigation the physiological role of these hormones in regulating human pigmentation. Alpha-melanocyte stimulating hormone and ACTH are both synthesized in the human epidermis, and their synthesis is upregulated by exposure to ultraviolet radiation (UVR). Activation of the MC1R by ligand binding results in stimulation of cAMP formation, which is a principal mechanism for inducing melanogenesis. The increase in cAMP is required for the pigmentary response of human melanocytes to UVR, and for allowing them to overcome the UVR-induced G1 arrest. Treatment of human melanocytes with alpha-MSH increases eumelanin synthesis, an effect that is expected to enhance photoprotection of the skin. Population studies have revealed more than 20 allelic variants of the MC1R gene. Some of these variants are overexpressed in individuals with skin type I or II, red hair, and poor tanning ability. Future studies will aim at further exploration of the role of these variants in MC1R function, and in determining constitutive human pigmentation, the response to sun exposure, and possibly the susceptibility to skin cancer.

The melanocortin-1 receptor and human pigmentation.

alpha-Melanocyte stimulating hormone (alpha-MSH) is known to be the main physiologic regulator for integumental pigmentation of various vertebrate species. However, the role of alpha-MSH and related melanocortins in the regulation of human cutaneous pigmentation is only beginning to be understood. Cloning of the melanocortin-1 receptor (MC1R), and the feasibility of establishing normal human epidermal melanocyte cultures have made it possible to demonstrate direct and specific biological effects of alpha-MSH on these cells. It is now recognized that both alpha-MSH and ACTH have similar mitogenic and melanogenic effects on human epidermal melanocytes. These effects are mediated by binding of these hormones to the specific MC1R that recognizes them both with similar affinity. Human MC1R is homologous to its mouse counterpart in that its activation leads to stimulation of eumelanin synthesis. MC1R is also the binding site for agouti signaling protein (ASP), the product of the agouti locus. Human epidermal melanocytes respond to purified recombinant mouse or human ASP, with a reduction in basal tyrosinase activity, and complete abrogation of the mitogenic and melanogenic effects of alpha-MSH. These results suggest that ASP induces pheomelanin synthesis by competing with alpha-MSH for binding to the MC1R. This receptor seems to be subject to regulation by a variety of paracrine and/or autocrine factors that are synthesized in response to exposure of the skin to ultraviolet radiation (UVR). Activation of MC1R seems to be pivotal for UV-induced melanogenesis, since stimulation of the cAMP pathway plays a key role in the melanogenic response of human epidermal melanocytes. The melanogenic response to UVR might be influenced by the presence of allelic variants of the MC1R gene. Allelic variants have been identified and shown to be associated with red hair, poor tanning ability, and possibly melanoma. The possible influence of these variants on the function of the MC1R needs to be investigated, in order to understand the physiological consequence of these mutations. Also, the interaction of alpha-MSH with other factors that are known to affect pigmentation needs to be better understood in order to define the role possible of this hormone and its receptor in acquired human cutaneous hyper- or hypopigmentation.

Pharyngocutaneous fistula following laryngectomy.

BACKGROUND: Pharyngocutaneous fistula (PCF) following laryngectomy is a serious complication, and its incidence varies from 7.6% to 50%. Despite the relative frequency of this complication, there is still uncertainty about the predisposing factors. METHODS: A retrospective study was performed in 295 patients who underwent total laryngectomy. RESULTS: Of the 295 patients, 37 (12.5%) developed PCF. The contributing factors,--such as early oral feeding postoperatively, prior radiotherapy or tracheostomy, accompanying neck dissection,--and the surgical technique failed to show a statistically significant effect. There was statistically significant association between tumor size and PCF formation. Also, when the suture materials used for the closure of the pharynx were compared, catgut showed a higher rate of PCF formation than vicryl (p < .05). CONCLUSIONS: The vicryl, when used as a suture material for the closure of the pharynx, seemed to decrease the fistula rate significantly, compared with catgut. Also, tumor stage was found to have a significant role in PCF formation, but no statistical significant difference could be demonstrated for other investigated parameters. We believe that after total laryngectomy, oral feeding can be started at the third postoperative day without increasing morbidity, which makes the patients feel more comfortable and confident without nasogastric tube.

Mitogenic and melanogenic stimulation of normal human melanocytes by melanotropic peptides.

The significance of melanotropic hormones as physiologic regulators of cutaneous pigmentation in humans is still controversial. Until recently, no direct effect for melanotropins could be demonstrated on human melanocytes. Here we present conclusive evidence that alpha-melanotropin (alpha-melanocyte-stimulating hormone, alpha-MSH) and the related hormone corticotropin (adrenocorticotropic hormone, ACTH) stimulate the proliferation and melanogenesis of human melanocytes maintained in culture in a growth medium lacking any AMP inducer. The minimal effective dose of either hormone is 0.1 nM. In time-course experiments, the increase in cell number and tyrosinase activity became evident after one treatment of the melanocytes with 100 nM alpha-MSH for 48 hr. The mitogenic effect gradually increased to 50-270% above control, depending on the individual melanocyte strain, with continuous treatment with 100 nM alpha-MSH for 8 days, whereas the melanogenic effect became maximal (70-450% increase above control) after 4 days of treatment. Western blot analysis of tyrosinase and the tyrosinase-related proteins TRP-1 and TRP-2 revealed that alpha-MSH increased the expression of those three melanogenic proteins. This was not accompanied by any change in their mRNA levels after brief (1.5-24 hr) or prolonged (6 days) treatment with 100 nM alpha-MSH, suggesting that the increased expression of these melanogenic proteins was due to posttranscriptional events. These results demonstrate both mitogenic and melanogenic effects of alpha-MSH and ACTH on human melanocytes. That both hormones are effective at subnanomolar concentrations, combined with the presence of melanotropin receptors on human melanocytes, strongly suggests that these melanotropins play a physiologic role in regulating human cutaneous pigmentation.

Acyclovir in the treatment of recurrent respiratory papillomatosis: a preliminary report.

INTRODUCTION: In this study, we evaluate the effect of acyclovir in the treatment of recurrent respiratory papillomatosis (RRP), in addition to CO2 surgery. MATERIALS AND METHODS: We include 12 patients who had aggressive RRP and required at least three prior endoscopic surgeries in this study. Acyclovir treatment started the day after the surgery. During the planned treatment period of 6 months, patients older than 5 years were asked to take the daily dose of 800 mg, and those younger than 5 years were asked to take 400 mg. RESULTS: Nine of 12 patients were disease free during the follow-up periods, which ranged from 14 to 25 months with a mean of 18 months. Only 3 patients who used the drug inadequately required reoperation. CONCLUSION: Because of the specific viral origin of RRP, we hope that addition of acyclovir to surgery will preclude or at least decrease the number of recurrences in this potentially fatal disease.