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Background Melanoma is an aggressive cutaneous cancer. Acral lentiginous melanoma is a melanoma subtype arising on palms, soles, and nail-units. The incidence, prevalence and prognosis differ among populations. The link between expression of major histocompatibility complex Class II alleles and melanoma progression is known. However, available studies report variable results regarding the association of melanoma with specific HLA Class II loci. Aims The aim of the study was to determine HLA Class II allele frequencies in acral lentiginous melanoma patients and healthy Mexican Mestizo individuals. Methods Eighteen patients with acral lentiginous melanoma and 99 healthy controls were recruited. HLA Class II typing was performed based on the sequence-specific oligonucleotide method. Results Three alleles were associated with increased susceptibility to develop acral lentiginous melanoma, namely: HLA-DRB1*13:01; pC = 0.02, odds ratio = 6.1, IC95% = 1.4-25.5, HLA-DQA1*01:03; pC = 0.001, odds ratio = 9.3, IC95% = 2.7-31.3 and HLA-DQB1*02:02; pC = 0.01, odds ratio = 3.7, IC95% = 1.4-10.3. Limitations The small sample size was a major limitation, although it included all acral lentiginous melanoma patients seen at the dermatology department of Dr. Manuel Gea González General Hospital during the study period. Conclusion HLA-DRB1*13:01, HLA-DQB1*02:02 and HLA-DQA*01:03 alleles are associated with increased susceptibility to develop acral lentiginous melanoma in Mexican Mestizo patients. [ABSTRACT FROM AUTHOR]

In isolated rat hearts perfused with HEPES and red blood cell-enriched buffers, we examined changes in left ventricular pressure induced by increases in heart rate or infusion of adenosine to investigate whether the negative force-frequency relation and the positive inotropic effect of adenosine are related to an inadequate oxygen supply provided by crystalloid perfusates. Hearts perfused with HEPES buffer at a constant flow demonstrated a negative force-frequency relation, whereas hearts perfused with red blood cell-enriched buffer exhibited a positive force-frequency relation. In contrast, HEPES buffer-perfused hearts showed a concentration-dependent increase in left ventricular systolic pressure [E[C.sub.50] = 7.0 [+ or -] 1.2 nM, maximal effect ([E.sub.max]) = 104 [+ or -] 2 and 84 [+ or -] 2 mmHg at 0.1 [micro]M and baseline, respectively] in response to adenosine, whereas hearts perfused with red blood cell-enriched buffer showed no change in left ventricular pressure. The positive inotropic effect of adenosine correlated with the simultaneous reduction in heart rate (r = 0.67, P < 0.01; E[C.sub.50] = 3.8 [+ or -] 1.4 nM, baseline 228 [+ or -] 21 beats/min to a minimum of 183 [+ or -] 22 beats/min at 0.1 [micro]M) and was abolished in isolated hearts paced to suppress the adenosine-induced bradycardia. In conclusion, these results indicate that the negative force-frequency relation and the positive inotropic effect of adenosine in the isolated rat heart are related to myocardial hypoxia, rather than functional peculiarities of the rat heart. hypoxia; myocardium; myocardial contractility

A machining fixture controls position and orientation of datum references (used to define important functional features of the geometry of a mechanical part) relative the reference frame for an NC program. Inaccuracies in fixture's location scheme result in a deviation of the work part from its nominal specified geometry. For a part to be acceptable this deviation must be within the limits allowed by the geometric tolerances specified. This paper addresses the problem of characterizing the acceptable level of inaccuracy in the location scheme so that the features machined on the part comply with the limits associated with its geometric tolerances. First we solve the 'forward problem' that involves predicting the tolerance deviation resulting at a feature from a known set of errors on the locators. However, the paper concentrates on solving the 'inverse' problem that involves establishing bounds on the errors of the locators to ensure that the limits specified by geometric tolerances at a feature are not violated.

This paper addresses the problem of computing frictionless optimal clamping schemes with form closure on three-dimensional parts with planar and cylindrical faces. Given a work part with a pre-defined 3-2-1 locator scheme, a set of polygonal convex regions on the clamping faces are defined as the admissible positions of the clamps. The work part-fixture contact is assumed to be of the point-surface type. Using extended screw theory, we present a linear algebraic method that computes the sub-regions of the clamping faces such that clamps located within them are guaranteed to achieve form closure. These are termed dependent regions of form closure, since the clamps must be placed according to a precise relationship. We develop methods to compute these regions on work parts with planar and cylindrical faces. This result is incorporated into a new linear programming formulation to compute frictionless optimal clamping schemes. Clamping schemes with form closure are robust when uncertainty, in knowledge of the external loads acting on the work part is present. Next, we extend the method to compute maximal independent regions of form closure. These are sub-regions of the dependent regions of form closure where the clamps can be placed completely independent of each other while maintaining form closure. When the clamps are placed within the independent regions of form closure, the clamping scheme is made robust against errors in their positions. [DOI: 10.1115/1.1471527]

This paper addresses the problem of synthesizing robust optimal clamping schemes on three-dimensional parts with planar faces, with and without friction. Given a work part with a pre-defined deterministic 3-2-1 location scheme, a set of polygonal convex regions on its faces are defined as areas of admissible clamp positions. A known set of external disturbing wrenches is also given. The frictionless case is considered first, and a new linear program is formulated to provide clamp locations that minimize the maximum clamping force. A transformation of the solution is presented that permits the extraction of both, the optimal positions of the clamps and the magnitude of the corresponding maximum clamping force. Friction is introduced next, and a linear program is presented that minimizes the maximum normal clamping force. We also extend the earlier formulations to support the case of frictionless clamping contacts on cylindrical faces. The result is a nonlinear (but convex) optimization problem that can be easily solved. Finally, we discuss a linear algebraic technique to find the directions, and associated relative motion rates, along which the clamps can be moved while maintaining the clamping forces constant. These lines of constant clamping force, as we name them, identify an equivalence set of clamping schemes (such that the maximum clamping force, given a set of disturbing wrenches, stays invariant). [DOI: 10.1115/1.1469520]

This paper addresses the problem of generating a we/l-conditioned, near-optimal deterministic 3-2-1 location scheme. Given are a workpart with identified planar datum faces, each with an associated convex region of admissible locator positions, and a set of disturbing twists (resulting from the processing operations on the workpart). First, screw theory is used to identify easily implementable necessary and sufficient conditions for deterministic positioning of the workpart in a 3-2-1 locator scheme. Next, the conditioning of a location scheme is studied and combinatorial algorithms are developed for synthesizing near-optimally conditioned locator schemes. Interesting decomposition and restrictions on the search space are identified to make the synthesis procedure efficient. [DOI: 10.1115/1.1381396]

ABSTRACT Lidocaine/prilocaine cream is a topical anesthetic commonly used in pediatric and dermatologic practice to obtain local anesthesia Common side effects include: transient skin blanching, erythema, urticaria, allergic contact dermatitis, [...]

Cutaneous malakoplakia is a rare infection-related granulomatous disease frequently associated with immunocompromised states. Foamy macrophages containing basophilic granules, called the Michaelis-Gutman bodies, are pathognomonic. We report a case of cutaneous malakoplakia in a 77-year-old male with pyoderma gangrenosum and a 2-year history of a non-healing malleolar ulcer treated successfully with cotrimoxazole. [ABSTRACT FROM AUTHOR]