Marek Vlk

Combination of Er:YAG laser and photodynamic therapy in the treatment of nodular basal cell carcinoma

Photodynamic therapy (PDT), via topical aminolevulinic acid (ALA) is an effective treatment for basal cell carcinomas not exceeding a depth of 2 mm. This limits the treatment of basal cell carcinoma (non‐melanoma skin cancer) to superficial forms and nodular therapy (only in aesthetically desired locations). This paper addresses the effectiveness of reducing tumor mass via initial Er:YAG laser ablation to depths that are therapeutically responsive to PDT with ALA.

Fractional Carbon Dioxide Laser Improves Nodular Basal Cell Carcinoma Treatment with Photodynamic Therapy with Methyl 5‐Aminolevulinate

Background The major limitation of photodynamic therapy with 5‐aminolevulinic acid (ALA‐PDT) is proper photosensitizer penetration. The nodular form of BCC (nBCC) is perceived as a contraindication to ALA‐PDT because the tumor layer is thicker than 2 mm. We have improved on the results of previous studies that used an ablative laser to limit tumor thickness. A fractional laser produces skin microtubules that can improve the penetration of ALA into tumors. Objective To evaluate the use of a fractional laser as pretreatment before ALA‐PDT for nBCC treatment in an 18‐month single‐blind clinical trial. Methods Fifty‐six verified nBCCs were ablated using a diode laser under ultrasound control. Half of the tumors were treated 3 weeks later using a fractional carbon dioxide laser, and the other half were treated using curettage (control). We then immediately treated with ALA‐PDT. Fluorescence and photography were evaluated and compared each month, and a final histopathologic examination was performed. Results Fifty‐two of 56 nBCCs in the fractional laser treatment group responded to ALA‐PDT, compared with only 45 of 56 in the control group. Fluorescence was higher in 53 cases in the treatment group; 3 cases demonstrated the same fluorescence level in both groups. Healing took longer in the treatment group, and there were more side effects. Conclusion Fractional laser pretreatment increases the fluorescence and clinical effectiveness of ALA‐PDT for the treatment of nBCC.

Ultrasound guided ablative-laser assisted photodynamic therapy of basal cell carcinoma (US-aL-PDT).

OBJECTIVE With proper noninvasive ultrasound measurement of tumor depth, case selection for laser pre-ablation followed by PDT is possible. This combination of methods provides a less invasive approach to the treatment of BCC. BACKGROUND DATA Basal cell carcinoma (BCC) primarily affects the face, and, therefore, radical excision is problematic because of the possibility of poor aesthetic outcomes. Photodynamic therapy (PDT) offers an advantage in aesthetic outcomes, but topical PDT is only effective for tumors with a depth up to 2 mm. MATERIALS AND METHODS Seventy-five histologically verified BCCs from 67 patients were selected and divided into three therapeutic groups based on the tumor depth, which was determined by 20 MHz skin ultrasound. The three groups were: A/<2 mm (PDT), B/ 2-3 mm (Er:YAG laser ablation+PDT), and C/>3 mm (diode laser ablation+PDT). The treatment consisted of laser ablation (or no ablation) followed by the application of methyl-aminolevulinate (MAL) and a 3-h treatment period using an occlusive bandage. Subsequently, illumination with 630 nm (MAL-PDT) was performed. MAL-PDT was repeated 1-3 weeks after the first treatment. A clinical evaluation was performed after 6 months. RESULTS A 100% clearance rate (CR) in the group with the deepest tumors was observed. In addition, a 94.7% CR occurred in the group with tumors 2-3 mm in depth, and an 81.2% CR was observed in the group with superficial tumors. CONCLUSIONS With proper ultrasound case selection and laser ablation before MAL-PDT, the depth of a BCC lesion is not a limiting factor for PDT, and aesthetic outcomes are very good. Therefore, ultrasound-guided ablative laser-assisted PDT of BCC can be the method of choice, particularly in aesthetically challenging cases.

Reactive Recovery from Machine Breakdown in Production Scheduling with Temporal Distance and Resource Constraints

One of the classical problems of real-life production scheduling is dynamics of manufacturing environments with new production demands coming and breaking machines during the schedule execution. Simple rescheduling from scratch in response to unexpected events occurring on the shop floor may require excessive computation time. Moreover, the recovered schedule may be deviated prohibitively from the ongoing schedule. This paper studies two methods how to modify a schedule in response to a resource failure: rightshift of affected activities and simple temporal network recovery. The importance is put on the speed of the rescheduling procedures as well as on the minimum deviation from the original schedule. The scheduling model is motivated by the FlowOpt project, which is based on Temporal Networks with Alternatives and supports simple temporal constraints between the activities.

Energy-Aware Production Scheduling with Power-Saving Modes

This study addresses optimization of production processes where machines have high energy consumption. One efficient way to reduce the energy expenses in production is to turn a machine off when it is not being used or switch it into an energy-saving mode. If the production has several machines and production demand that varies in time, the energy saving can be substantial; the cost reduction can be achieved by an appropriate production schedule that could control the switching between the energy modes with respect to the required production volume. Therefore, inspired by real production processes of glass tempering and steel hardening, this paper addresses the scheduling of jobs with release times and deadlines on parallel machines. The objective is to find a schedule of the jobs and a switching between the power modes of the machines so that the total energy consumption is minimized. Moreover, to further generalize the scheduling problem to other production processes, we assume that the processing time of the jobs is mode-dependent, i.e., the processing time of a job depends on the mode in which a machine is operating. The study provides an efficient Branch-and-Price algorithm and compares two approaches (based on Integer Linear Programming and Constraint Programming) for solving the subproblem.

Phenotypic characterization of oral mucosa: what is normal?

BACKGROUND Knowledge of the phenotypic pattern of oral squamous epithelium is important in the histopathologic evaluation of lesions including cancer. The literature on normal epithelium is controversial as the phenotype has not been evaluated in samples from completely healthy tissue donors without a history of tobacco and alcohol exposure. METHODS In this study, we evaluated normal upper lip fornix and gingival mucosa from carefully selected young healthy donors without a history of smoking and alcohol exposure, and keratin types 8, 10, 14, and 17, filaggrin, and Ki67 were investigated in these donors. The results were compared with profile of epithelium from leukoplakia. RESULTS The results demonstrated that the phenotypic patterns of gingiva and upper lip fornix mucosa were different. Surprisingly, a high proportion of gingival samples exhibited keratin 8 and a suprabasal signal for keratin 14. These patterns were compared with that of human oral leukoplakia, and some phenotypic similarities were noted. CONCLUSIONS These results demonstrated oral epithelium phenotypic plasticity based on functional requirements of the microenvironment, which can be used in diagnosis.

Hierarchical Task Model for Resource Failure Recovery in Production Scheduling

Attaining optimal results in real-life scheduling is hindered by a number of problems. One such problem is dynamics of manufacturing environments with breaking-down resources and hot orders coming during the schedule execution. A traditional approach to react to unexpected events occurring on the shop floor is generating a new schedule from scratch. Complete rescheduling, however, may require excessive computation time. Moreover, the recovered schedule may deviate a lot from the ongoing schedule. Some works have focused on tackling these shortcomings, but none of the existing approaches tries to substitute jobs that cannot be executed with a set of alternative jobs. This paper describes the scheduling model suitable for dealing with unforeseen events using the possibility of alternative processes and proposes an efficient heuristic-based approach to recover an ongoing schedule from a resource failure.

Machine Breakdown Recovery in Production Scheduling with Simple Temporal Constraints

One of the problems of real-life production scheduling is dynamics of manufacturing environments with new production demands coming and breaking machines during the schedule execution. Simple rescheduling from scratch in response to unexpected events may require excessive computation time. Moreover, the recovered schedule may deviate prohibitively from the ongoing schedule. This paper studies two methods how to modify a schedule in response to a machine breakdown: right-shift of affected activities and simple temporal network recovery. The importance is put on the speed of the rescheduling procedures as well as on the minimum deviation from the original schedule. In addition, this paper models the problem as a Mixed Integer Program and compares the proposed algorithms to the model using the mosek optimizer. The scheduling model is motivated by the FlowOpt project, which is based on Temporal Networks with Alternatives and supports simple temporal constraints between the activities.

The efficacy of diode laser removal of leukoplakias on the tongue and in lower buccal cavity compared to other buccal cavity locations. A two-year study

Introduction. Leukoplakias of the buccal cavity are premalignant lesions with a significant 0–20% potential for malignant transformation. In addition to active follow-up screening procedures, a number of surgical interventions are recommended for their removal. One of the preferred procedures is laser ablation with consecutive histopathology using one of the many types of lasers. The efficacy of such procedure with respect to the lesion location is, however, unclear. Many studies are contradictory. Some shows laser ablations as prevention of malignisation other see it as increased risk. Aim of this is to test treatment in different locations for two years. Material and method. An outpatient ablation by a 980mm diode laser of lesions on the tongue and in the lower buccal cavity (Group A) and lesions in other parts of the buccal cavity (Group B) were performed under local anaesthesia. In total, 76 lesions were treated in 66 patients. Recurrence after 1, 3, 6, 9, 12, and 24 months were followed up. Initially, all lesions were histopathologically tested. Concurrently, the subjective tolerance of the procedure was monitored, using a 1 (ideal) to 5 (worst) scale. Results. Clearing rate of lesions was of 84.6% for Group A and of 94.7% for Group B. In two patients (3% of Group A) malignant transformation occurred which was not observed in Group B. Patient toleration in various time intervals was always higher in Group B, but generally was very high in both groups. Conclusion. Malignant transformation of leukoplakias does occur even after laser ablation, and for this reason it is necessary to subject the patients to systematic follow-ups. It is significantly higher risk of recurrences and malign transformation in tongue and oral base. Laser ablation is a simple and well-tolerated procedure with high clearing rate.