Lower eyelid reconstruction with pericranium graft and Mustarde flap. / Reconstrucción de párpado inferior mediante injerto de pericráneo y colgajo de Mustardé.

We report the case of a 68-year-old man with a left lower eyelid basal cell carcinoma with squamous differentiation. Resection was performed under frozen section technique and the defect (inner canthus, two thirds of the lower eyelid and 2.5cm of the cheek) reconstructed 2 days after surgery in a single surgical operation: posterior lamella with pericranial graft and anterior lamella with Mustarde flap. After one year of follow-up, the patient has an adequate appearance, good eyelid support and position, vascularized tissue like the native eyelid and no tumor recurrence.

Sarcoma de Kaposi palpebral bilateral en un paciente virus de la inmunodeficiencia humana negativo / Bilateral eyelid Kaposi's sarcoma in an HIV-negative patient

CASO CLÍNICO: Un varón de 70 años, procedente de Sicilia, acude con una masa palpebral bilateral con afectación tarsal conjuntival, que resultó ser un sarcoma de Kaposi al examen histológico. Se demostró afectación cutánea y pulmonar por el sarcoma de Kaposi. El paciente no tenía un diagnóstico previo de infección por el virus de la inmunodeficiencia humana. Este caso fue tratado con éxito tras 5 ciclos de quimioterapia con doxorrubicina liposomal, con resolución de las lesiones palpebrales, cutáneas y pulmonares. Conclusiones: La localización en el párpado es una posible manifestación inicial, aunque rara, del sarcoma de Kaposi en personas de edad avanzada negativos para el virus de la inmunodeficiencia humana. La doxorrubicina liposomal es un tratamiento seguro y efectivo

CASE REPORT: We report a case of 70-year-old male from Sicily, who presented with a bilateral eyelid mass involving the tarsal conjunctiva, found to be Kaposi's sarcoma on histologic examination. Cutaneous and pulmonary Kaposi's sarcoma involvement was documented. The patient had no prior diagnosis of human immunodeficiency virus infection. This case was managed successfully after the completion of five cycles of chemotherapy with liposomal doxorubicin, and his eyelid, skin and pulmonary lesions disappeared. CONCLUSIONS: Location in the eyelid is a possible, though rare, initial solitary manifestation of Kaposi's sarcoma in elderly HIV-negative patients. Liposomal doxorubicin is a safe and effective treatment

Bilateral eyelid Kaposi's sarcoma in an HIV-negative patient. / Sarcoma de Kaposi palpebral bilateral en un paciente virus de la inmunodeficiencia humana negativo.

CASE REPORT: We report a case of 70-year-old male from Sicily, who presented with a bilateral eyelid mass involving the tarsal conjunctiva, found to be Kaposi's sarcoma on histologic examination. Cutaneous and pulmonary Kaposi's sarcoma involvement was documented. The patient had no prior diagnosis of human immunodeficiency virus infection. This case was managed successfully after the completion of five cycles of chemotherapy with liposomal doxorubicin, and his eyelid, skin and pulmonary lesions disappeared. CONCLUSIONS: Location in the eyelid is a possible, though rare, initial solitary manifestation of Kaposi's sarcoma in elderly HIV-negative patients. Liposomal doxorubicin is a safe and effective treatment.

Cierre angular secundario al uso de lorazepam en paciente con miopía magna / Angle closure secondary to the use of lorazepam in patient with myopia magna

CASO CLÍNICO: Miope magna con cámara anterior estrecha que presentó cierre angular secundario a lorazepam. DISCUSIÓN: El cierre angular generalmente ocurre en pacientes predispuestos desencadenado por factores precipitantes. Muchos fármacos de uso rutinario en la práctica clínica podrían ejercer como factor responsable del cierre angular secundario

CASE REPORT: Myopic magna with narrow anterior chamber that presented with a secondary angle closure due to lorazepam. DISCUSSION: Angle closure usually occurs in predisposed patients and is triggered by precipitating factors. Many drugs routinely used in clinical practice could act as a factor responsible for the secondary angle closure

Drusas del nervio óptico / Optic nerve drusen

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Angle closure secondary to the use of lorazepam in patient with myopia magna.

CASE REPORT: Myopic magna with narrow anterior chamber that presented with a secondary angle closure due to lorazepam. DISCUSSION: Angle closure usually occurs in predisposed patients and is triggered by precipitating factors. Many drugs routinely used in clinical practice could act as a factor responsible for the secondary angle closure.

Chemical modification and site-directed mutagenesis of human liver arginase: evidence that the imidazole group of histidine-141 is not involved in substrate binding.

Native and wild-type recombinant human liver arginases (EC 3.5.3.1) were photoinactivated by Rose bengal, and protection was afforded by the competitive inhibitor l-lysine. The dissociation constant for the enzyme-protector complex was essentially equal to the corresponding K(i) value. Upon mutation of His141 by phenylalanine, the enzyme activity was reduced to 6-10% of wild-type activity, with no changes in K(m) for arginine or K(i) for l-lysine or l-ornithine. The subunit composition of active enzyme was not altered by mutation, but the mutant H141F was markedly more sensitive to trypsin inactivation and completely insensitive to inactivation by diethyl pyrocarbonate (DEPC) and photoinactivation. Species with histidine groups blocked with DEPC were also insensitive to photoinactivation. We conclude that His141, which is the target for both inactivating procedures, is not involved in substrate binding, but plays a critical, albeit not essential role in the hydrolysis of enzyme-bound substrate.

Evidence that histidine-163 is critical for catalytic activity, but not for substrate binding to Escherichia coli agmatinase.

Agmatinase (agmatine ureohydrolase, EC 3.5.3.11) from Escherichia coli was inactivated by diethyl pyrocarbonate (DEPC) and illumination in the presence of Rose bengal. Protection against photoinactivation was afforded by the product putrescine, and the dissociation constant of the enzyme-protector complex (12 mM) was essentially equal to the K(i) value for this compound acting as a competitive inhibitor of agmatine hydrolysis. Upon mutation of His163 by phenylalanine, the agmatinase activity was reduced to 3-5% of wild-type activity, without any change in K(m) for agmatine or K(i) for putrescine inhibition. The mutant was insensitive to DEPC and dye-sensitized inactivations. We conclude that His163 plays an important role in the catalytic function of agmatinase, but it is not directly involved in substrate binding.

Manganese is essential for catalytic activity of Escherichia coli agmatinase.

Purified Escherichia coli agmatinase (EC 3.5.3.11) expressed the same activity in the absence or presence of added Mn2+ (0-5mM). However, it was strongly inhibited by Co2+, Ni2+, and Zn2+ and almost half inactivated by EDTA. Partial inactivation by EDTA yielded enzyme species containing 0.85 +/- 0.1 Mn2+/subunit, and it was accompanied by a decrease in intensity of fluorescence emission and a red shift from the emission maximum of 340 nm to 346 nm, indicating the movement of tryptophane residues to a more polar environment. The activity and fluorescence properties of fully activated agmatinase were restored by incubation of dialysed species with Mn2+. Manganese-free species, obtained by treatment with EDTA and guanidinium chloride (3 M), were active only in the presence of added Mn2+. Results obtained, which represent the first demonstration of the essentiality of Mn2+ for agmatinase activity, are discussed in connection with a possible binuclear metal center in the enzyme.

Manganese-dependent inhibition of human liver arginase by borate.

Full activation of human liver arginase (EC 3.5.3.1), by incubation with 5 mM Mn2+ for 10 min at 60 degrees C, resulted in increased Vmax and a higher sensitivity of the enzyme to borate inhibition, with no change in the K(m) for arginine. Borate behaved as an S-hyperbolic I-hyperbolic non-competitive inhibitor and had no effect on the interaction of the enzyme with the competitive inhibitors L-ornithine (Ki = 2 +/- 0.5 mM), L-lysine (Ki = 2.5 +/- 0.4 mM), and guanidinium chloride (Ki = 100 +/- 10 mM). The pH dependence of the inhibition was consistent with tetrahedral B(OH)4- being the inhibitor, rather than trigonal B(OH)3. We suggest that arginase activity is associated with a tightly bound Mn2+ whose catalytic action may be stimulated by addition of a more loosely bound Mn2+, to generate a fully activated enzyme form. The Mn2+ dependence and partial character of borate inhibition are explained by assuming that borate binds in close proximity to the loosely bound Mn2+ and interferes with its stimulatory action. Although borate protects against inactivation of the enzyme by diethyl pyrocarbonate (DEPC), the DEPC-sensitive residue is not considered as a ligand for borate binding, since chemically modified species, which retain about 10% of enzymatic activity, were also sensitive to the inhibitor.