Chlorophyll and pheophytin protonated and deprotonated ions: Observation and theory.

Pheophytin a and chlorophyll a have been investigated by electrospray mass spectrometry in the positive and negative modes, in view of the importance of the knowledge of their properties in photosynthesis. Pheophytin and chlorophyll are both observed intensely in the protonated mode, and their main fragmentation route is the loss of their phytyl chain. Pheophytin is observed intact in the negative mode, while under collisions, it is primarily cleaved beyond the phytyl chain and loses the attaching propionate group. Chlorophyll is not detected in normal conditions in the negative mode, but addition of methanol solvent molecule is detected. Fragmentation of this adduct primarily forms a product (-30 amu) that dissociates into dephytyllated deprotonated chlorophyll. Semi-empirical molecular dynamics calculations show that the phytyl chain is unfolded from the chlorin cycle in pheophytin a and folded in chlorophyll a. Density functional theory calculations have been conducted to locate the charges on protonated and deprotonated pheophytin a and chlorophyll a and have found the major location sites that are notably more stable in energy by more than 0.5 eV than the others. The deprotonation site is found identical for pheophytin a and the chlorophyll a-methanol adduct. This is in line with experiment and calculation locating the addition of methanol on a double bond of deprotonated chlorophyll a.

Hepatic Sinusoidal Obstruction Syndrome in a child after chemotherapy for medulloblastoma.

Hepatic Sinusoidal Obstruction Syndrome (HSOS), the new name given to veno-occlusive disease (VOD) of the liver, is a well-known complication of high-dose chemotherapy employed with hematopoietic stem cell transplantation, but it has rarely been observed in children who receive conventional chemotherapy. HSOS following standard chemotherapy has been reported in patients receiving vincristine, actinomycin D, and cyclophosphamide for the treatment of Wilms tumor and more rarely rhabdomyosarcoma. We report a 14-year-old boy with high risk medulloblastoma treated with craniospinal radiation followed by chemotherapy, who experienced severe HSOS after only one course of chemotherapy including carboplatin, vincristine, and cyclophosphamide. To our knowledge, this is the second report of HSOS after standard dose chemotherapy for brain tumor in childhood.

Allogeneic stem cell transplantation for Glanzmann thrombasthenia.

Glanzmann thrombasthenia (GT) is a rare autosomal recessive bleeding disorder characterized by normal platelet count, but lack of platelet aggregation. The molecular basis is linked to quantitative and/or qualitative abnormalities of the membrane glycoprotein IIb/IIIa complexes. Usually it is associated with mild bleeding but may lead to severe and potentially fatal hemorrhages. Allogeneic hematopoietic stem cell transplantation (HSCT) is the only curative treatment. However, because of the risks associated with HSCT, it is generally not recommended unless there are life threatening hemorrhages, or the patient has developed refractoriness to platelet transfusion due to antibody formation. Herein, we report an 11-year-old female from United Arab Emirates (UAE) with severe GT and anti platelet alloimmunization successfully treated with HSCT from her HLA-identical sibling.

Diffuse calcinosis cutis in a patient with congenital leukemia and leukemia cutis.

We report an unusual case of congenital leukemia with leukemia cutis (LC) and diffuse calcinosis cutis. A newborn girl presented with widespread dusky red and yellowish cutaneous nodules and papules. Bone marrow morphology was consistent with the diagnosis of acute monocytic leukemia of the FAB M5 type. Skin biopsy specimens confirmed the presence of a leukemic infiltrate and revealed calcium salt deposition in the papillary and reticular dermis. Calcinosis was diffuse in the whole skin but spared other organs. Vascular calcification was not present. Serum calcium levels oscillated between 2.5 and 2.86 mmol/l, and phosphorus, parathyroid hormone and 25-hydroxyvitamin D(3) levels were normal. There were diffuse osteoporosis and spontaneous fractures of small tubular bones. The patient responded to chemotherapy but, following consolidation treatment, developed sepsis and died at 120 days of age. Congenital leukemia is rare and LC is uncommon. Hypercalcemia may be a complication of leukemia, which leads to multiorgan metastatic calcification. Despite the absence of frank hypercalcemia, the presence of bone lesions suggests that the patient's calcinosis cutis was of the metastatic type. However, the cutaneous leukemic infiltrate may also represent a triggering factor for calcium deposition in the skin.