Optimized Photodynamic Therapy with Systemic Photosensitizer Following Debulking Technique for Nonmelanoma Skin Cancers

BACKGROUND: The thickness and depth of invasion of skin tumors may be limiting factors for topical photosensitizer-based photodynamic therapy (PDT). The use of PDT with systemic photosensitizer needs to be further explored as a modality of treatment for nonmelanoma skin cancer (NMSC). OBJECTIVE: The objective was to present six patients with multiple, nodular, and/or pigmented NMSC treated successfully with purified hematoporphyrin derivative (PHD) and PDT using prior debulking. METHODS: After 24 hours of systemic PHD (1.5 mg/kg), 12 lesions of NMSC were selected for PHD-PDT alone and 6 nodular/elevated lesions for PHD-PDT following a debulking procedure. The tumor area was illuminated in one single-dose session of 300 J/cm(2), at an intensity range of 130 to 150 mW/cm(2), with a 630-nm-wavelength diode laser. RESULTS: The prior curettage provided significant reduction in volume and/or pigmentation of lesions. After the session of PHD-PDT with prior curettage and additional topical 20% ALA-PDT in two lesions or PHD-PDT alone, 83% (5/6) of lesions and 58% (7/12) of lesions, respectively, maintained a complete clinical response, 22.2+/-8.9 months of follow-up. CONCLUSIONS: The combination of prior debulking with systemic agents-PDT appears to be a good option for multiple, pigmented, and/or nodular lesions of NMSC and can allow the improvement of clinical results.     

Assessment of Aortic Coarctation and Collateral Circulation By Biplane Transesophageal Echocardiography

Our experience in using biplane transesophageal echocardiography in the assessment of coarctation of the aorta is described.     

Sinus Node Reentrant Tachycardia

This review article discusses the electrophysiological basis of sinus node reentry, clinical features of sinus node reentry, and the management of this uncommon tachycardia with drugs and ablative therapy. It also proposes the use of the term "sinoatrial reentrant tachycardia" for this form of tachycardia.     

A comparative conformational analysis of thimet oligopeptidase (EC 3.4.24.15) substrates

The specificity of thimet oligopeptidase (EC 3.4.24.15) (TOP 24.15) does not agree with theoretical models devised to explain the specificity characteristic of peptidases toward certain sequences of amino acid residues. According to previous studies peptide chains hydrolyzed by TOP 24.15 adopt similar main chain conformations, although with different and in some cases small probabilities of occurrence in aqueous solution. To determine specific structural features recognized by TOP 24.15, a conformational search including eight polypeptides with known susceptibilities for catalytic hydrolysis was executed and the distribution of each main chain conformation found in the search was tabulated. Two sets of main chain conformations were selected, those common to all peptides in the study and those common only to substrates of TOP 24.15. The former set is very small and includes mainly extended conformations. In contrast, the latter set is large and its conformations are coiled and exhibit sharp turns coincident with positions of hydrolysis by TOP 24.15. These results indicate a possible basis for the selectivity of TOP 24.15.     

Synthesis of human angiotensinogen (1-17) containing one of the putative glycosylation binding sites and its hydrolysis by human renin and porcine pepsin

The N-terminal heptadecapeptide of human angiotensinogen (Asp-Arg-Val-Tyr-Ile-His-Pro-Phe-His-Leu-Val-Ile-His-Asn-Glu-Ser-Thr-NH₂), with the C-terminal carboxyl group amidated, was synthesized in order to study the role of Asn-Glu-Ser, a putative carbohydrate binding site, on the hydrolysis by human renin. The synthesis was performed by fragment condensation using the Honzl and Rudinger azide procedure. In our conditions for azide segment condensation, histidine racemization was demonstrated to be negligible for most of the condensation reactions. Human renin liberates angiotensin I from h-angiotensinogen (1-17)-NH₂ with a K_m value of 3.4 × 10^?5m , at pH 7.3 and 37° being similar to h-angiotensinogen (1-13), an analog without the carbohydrate binding site. However, the V_max value of 4.1 × 10^?9mol/G.U. min is one order of magnitude higher. Porcine pepsin was demonstrated to cleave preferentially Leu¹⁰-Val¹¹ bond and, surprisingly, His⁹-Leu¹⁰ as well.     

Transgastric Ultrasonography: A New Approach for Imaging the Abdominal Structures and Vessels

For the first time, the feasibility of using transgastric ultrasonography to examine the abdominal vasculature and organs has been demonstrated. An illustrative case report details how this approach was utilized in a patient following abdominal aortic aneurysm resection, in whom surface ultrasonography was not feasible. The diagnostic potential of this new approach is discussed. Possible modifications to improve the technique and to facilitate the examination in a wider range of patients are also suggested. Further studies are needed to better define the technique and role of transgastric ultrasonography in the evaluation of the abdominal aorta and its branches and other abdominal structures. (ECHOCARDIOGRAPHY, Volume 8, May 1991)     

Enhanced fibrinolytic activity during cardiopulmonary bypass in open-heart surgery in man is caused by extrinsic (tissue-type) plasminogen activator

The nature of the enhanced blood fibrinolytic activity which is known to occur during cardiopulmonary bypass is not understood. We show here that the cause is an increase in extrinsic (tissue-type) plasminogen activator. In six patients, the nature of the enhanced blood fibrinolytic activity that evolved during cardiopulmonary bypass was characterized by differential inhibition using the fibrin plate method and was shown to be C1-inactivator-resistant (extrinsic-activator activity). The C1-inactivator-resistant-activator activity was completely quenched by an antibody against extrinsic (tissue-type) plasminogen activator but not by antiurokinase, proving that the activity was due to the presence of extrinsic (tissue-type) plasminogen activator. The concentration of extrinsic (tissue-type) plasminogen activator increased during cardiopulmonary bypass and disappeared rapidly thereafter. Fibrinogen, plasminogen and alpha 2-antiplasmin were not consumed during cardiopulmonary bypass, while no increase or occasionally a moderate one in fibrinogen degradation products occurred. This is in accord with the property of extrinsic (tissue-type) plasminogen activator which activates plasminogen predominantly at sites where fibrin is present and not in the free circulation.