A truncating PET100 variant causing fatal infantile lactic acidosis and isolated cytochrome c oxidase deficiency

Isolated mitochondrial complex IV (cytochrome c oxidase) deficiency is an important cause of mitochondrial disease in children and adults. It is genetically heterogeneous, given that both mtDNA-encoded and nuclear-encoded gene products contribute to structural components and assembly factors. Pathogenic variants within these proteins are associated with clinical variability ranging from isolated organ involvement to multisystem disease presentations. Defects in more than 10 complex IV assembly factors have been described including a recent Lebanese founder mutation in PET100 in patients presenting with Leigh syndrome. We report the clinical and molecular investigation of a patient with a fatal, neonatal-onset isolated complex IV deficiency associated with multiorgan involvement born to consanguineous, first-cousin British Asian parents. Exome sequencing revealed a homozygous truncating variant (c.142C>T, p.(Gln48*)) in the PET100 gene that results in a complete loss of enzyme activity and assembly of the holocomplex. Our report confirms PET100 mutation as an important cause of isolated complex IV deficiency outside of the Lebanese population, extending the phenotypic spectrum associated with abnormalities within this gene.     

Function of the long spinal cord pathways in cervical spinal stenosis--an electrophysiologic study

Cervical spinal stenosis is radiologically defined by a reduced inner diameter (X less than 13 mm) of the cord canal and in most cases etiologically connected with spondylosis. The following study describes the results of non-invasive assessment of the long ascending and descending spinal tracts in 12 patients. The long ascending spinal tracts were examined by spinal and cortical SEP after stimulation of the tibial nerve; for the assessment of the descending spinal tracts motor responses of the tibial anterior muscle were recorded after non-invasive stimulation of the motor cortex. Clinically symptomatic patients (N = 2) exhibited clear-cut functional motor and sensory deficits of the central pathways. In asymptomatic patients (N = 10) corticomotoneuronal latencies to the lower limbs were increased in 8 cases. In comparison, increased central sensory latencies were found in 9/10. In conclusion, the studies showed that the technique of non-invasive stimulation of the motor cortex may play a role in the detection of subclinical lesions of the long descending motor tracts due to a chronic mechanical irritation.     

Primary tumor cells of myeloma patients induce interleukin-6 secretion in long-term bone marrow cultures

Long-term bone marrow cultures (LTBMC) from patients with multiple myeloma (MM) and normal donors were analyzed for immunophenotype and cytokine production. Both LTBMC adherent cells from myeloma and normal donor origin expressed CD10, CD13, the adhesion molecules CD44, CD54, vascular cell adhesion molecule 1, very late antigen 2 (VLA-2), and VLA- 5, and were positive for extracellular matrix components fibronectin, laminin, and collagen types 3 and 4. LTBMC from myeloma patients and normal donors spontaneously secreted interleukin-6 (IL-6). However, levels of IL-6 correlated with the stage of disease; highest levels of IL-6 were found in LTBMC from patients with active myeloma. To identify the origin of IL-6 production, LTBMC from MM patients and normal donors were cocultured with BM-derived myeloma cells and cells from myeloma cell lines. IL-6 was induced by plasma cell lines that adhered to LTBMC such as ARH-77 and RPMI-8226, but not by nonadhering cell lines U266 and FRAVEL. Myeloma cells strongly stimulated IL-6 secretion in cocultures with LTBMC adherent cells from normal donors and myeloma patients. When direct cellular contact between LTBMC and plasma cells was prevented by tissue-culture inserts, no IL-6 production was induced. This implies that intimate cell-cell contact is a prerequisite for IL-6 induction. Binding of purified myeloma cells to LTBMC adherent cells was partly inhibited by monoclonal antibodies against adhesion molecules VLA-4, CD44, and lymphocyte function-associated antigen 1 (LFA-1) present on the plasma cell. Antibodies against VLA-4, CD29, and LFA-1 also inhibited the induced IL-6 secretion in plasma cell-LTBMC cocultures. In situ hybridization studies performed before and after coculture with plasma cells indicated that LTBMC adherent cells produce the IL-6. These results suggest that the high levels of IL-6 found in LTBMC of MM patients with active disease are a reflection of their previous contact with tumor cells in vivo. These results provide a new perspective on tumor growth in MM and emphasize the importance of plasma cell-LTBMC interaction in the pathophysiology of MM.     

Sezary cell morphology induced in peripheral blood lymphocytes: re- evaluation

In this study we examined the effect of mitogens and epidermal cells in inducing a Sezary cell morphology in normal peripheral blood lymphocytes. Peripheral blood mononuclear cells from six healthy volunteers were stimulated with the mitogens phytohemaglutinin and concanavalin A, and also cocultivated with human epidermal cell cultures. Incubation times with mitogens and epidermal cells were four days and stimulation of the lymphocytes by mitogens was confirmed by standard 3H-thymidine uptake. Standard transmission electron microscopy showed that in the mitogen-driven system 20% to 60% (33 +/- 15%) and in the epidermal cell-driven system 5% to 15% (8 +/- 4%) of the lymphoid cells exhibited mild to moderate indentation of the nuclei with nuclear contour indices (NCI) of 4.6 to 6.5 but no Sezary cells were observed (cells with NCI greater than 6.5 and up to 19.2). In the mitogen- stimulated preparation 2% to 5% (3 +/- 1%) of the lymphoid cells showed nuclear multilobulation resembling the cells seen in adult T cell lymphoma/leukemia. Incubation of mononuclear cells for longer periods of up to 4 weeks with mitogens and exogenous IL-2 resulted in no further morphologic changes. Using an indirect immunogold technique at the electron microscopic level, the cells showing nuclear indentation or lobulation were shown to bear both T helper (CD4) and T suppressor (CD8) cell phenotypes in a similar ratio to the total numbers of T helper and T suppressor cells present. Mitogens and epidermal cells are thus not able to induce a morphologic change to Sezary cells in normal peripheral blood lymphocytes.     

Is there a Rationale for Autologous Breast Reconstruction in Older Patients? A Retrospective Single Center Analysis of Quality of life,Complications and Comorbidities after DIEP or ms‐TRAM Flap Using the BREAST‐Q

Autologous breast reconstruction with the deep inferior epigastric perforator (DIEP) or muscle‐sparing transverse rectus abdominis myocutaneous (ms‐TRAM) flap is a common method in the majority of patients after mastectomy. Because of an increased perioperative risk profile the benefit in older patients is questionable. To assess the postoperative quality of life and peri‐ and post‐operative complications of older compared to younger patients is the aim of this retrospective study. In a retrospective analysis 39 older (i.e. >60 years) and 140 younger patients (i.e. <60 years) with autologous breast reconstruction in the Department of Plastic Surgery at the University Hospital of Erlangen‐Nuernberg were surveyed at least 6 month postoperative using the BREAST‐Q questionnaire. Correlations were generated between comorbidities and complications. Significant differences were observed regarding hospitalization, pre‐existing diseases and the choice of DIEP versus ms‐TRAM flaps. Parameters such as major and minor complications, bulging or hernia and risk factors (e.g. smoking or obesity) showed no significant differences. The results of the questionnaire parameters showed no significant difference between both groups, revealing high satisfaction with the aesthetic result and an improvement in quality of life independent of age. Autologous breast reconstruction after mastectomy generates a gain in quality of life and shows a good to excellent overall satisfaction in older as well as younger patients. Despite a longer hospitalization and a different risk profile there were no significant differences regarding minor and major complications in the postoperative course. Hence autologous breast reconstruction for older patients is justified and should be taken into consideration.     

Purging of acute myeloid leukemic cells by ether lipids and hyperthermia

Ether lipids (EL) and hyperthermia have been shown to possess a relatively selective cytotoxicity to leukemic cells. In this study, the combined effects of EL (ET-18-OCH3, ET-16-NHCOCH3, or BM 41.440) and hyperthermia on the growth of hematopoietic progenitors, myeloid leukemic cell lines, and leukemic cells obtained from patients with acute myeloid leukemia (AML) were examined to determine if this combination resulted in a greater selective killing of leukemic cells than that achieved by either EL or heat alone. When the cells were treated simultaneously with EL (50 micrograms/mL) and hyperthermia (42 degrees C) for one hour, the killing of leukemic cell line cells was enhanced considerably. Among the three EL, however, the combination of ET-18-OCH3 and heat seemed to be the most cytotoxic to leukemic cell line cells with no effect on the growth of hematopoietic progenitors. An increase in the duration of treatment with ET-18-OCH3 to four hours with heat added during the last hour resulted in a further reduction of leukemic cell line cells while sparing 50% of hematopoietic progenitors after cryopreservation. The combined treatment with ET-18-OCH3 and heat also inhibited the growth of leukemic progenitors obtained from AML patients by 97% to 100%. These data indicate that the combined treatment with EL and hyperthermia might offer an efficient means to eliminate myeloid leukemic cells in vitro.     

Characterization of primitive subpopulations of normal and leukemic cells present in the blood of patients with newly diagnosed as well as established chronic myeloid leukemia

Elevated numbers of primitive Philadelphia chromosome-positive (Ph+) progenitors, including long-term culture-initiating cells (LTC-IC) as well as colony-forming cells (CFC), have been previously described in the blood of patients with chronic myeloid leukemia (CML) in chronic phase with high white blood cell counts. In the present study, which focused primarily on an analysis of circulating progenitors present in such patients at diagnosis, we discovered the frequent and occasionally exclusive presence of circulating normal (Ph-) LTC-IC, often at levels above those seen for LTC-IC in the blood of normal individuals. The presence of detectable numbers of circulating Ph- LTC-IC was independent of the fact that the same peripheral blood samples also contained elevated numbers of predominantly or exclusively Ph+ CFC. Interestingly, both the Ph+ and Ph- LTC-IC in these samples were CD34+CD71- and variably CD38- and Thy-1+, as previously documented for LTC-IC in normal marrow. Thus, neither CD38 nor Thy-1 expression was useful for discriminating between Ph+ and Ph- LTC-IC in mixed populations. Nevertheless, an association of these phenotypes with LTC- IC function did allow highly enriched (> 5% pure) suspensions of either Ph+ or Ph- LTC-IC to be obtained from selected samples of CML blood in which the initial LTC-IC population was either predominantly Ph+ or Ph- , respectively. These findings suggest that the mechanisms causing mobilization of leukemic stem cells in untreated CML patients may affect their normal counterparts. They also indicate a possible new source of autologous cells for the support of intensive therapy of CML patients. Finally, they provide a method for obtaining the most highly purified populations of Ph+ LTC-IC described to date. This method should be useful for further analyses of the molecular activities of these very primitive neoplastic cells.     

The SETX missense variation spectrum as evaluated in patients with ALS4-like motor neuron diseases

Mutations in the senataxin (SETX) gene can cause amyotrophic lateral sclerosis 4 (ALS4), an autosomal dominant form of juvenile onset amyotrophic lateral sclerosis, or result in autosomal recessive ataxia with oculomotor apraxia type 2. Great caution regarding the possible disease causation, especially of missense variations, has to be taken. Here, we evaluated the significance of all previously reported SETX missense mutations as well as six newly identified variations in 54 patients suspected of having ALS4. Yet, epidemiologic and in silico evidence indicates that all newly identified variations and two previously published ALS4-related missense variations (C1554G and I2547T) are most likely non-pathogenic, demonstrating the problems of interpretation of SETX missense alleles in the absence of functional assays.