Mutation in mitochondrial complex IV subunit COX5A causes pulmonary arterial hypertension,lactic acidemia,and failure to thrive

COX5A is a nuclear‐encoded subunit of mitochondrial respiratory chain complex IV (cytochrome c oxidase). We present patients with a homozygous pathogenic variant in the COX5A gene. Clinical details of two affected siblings suffering from early‐onset pulmonary arterial hypertension, lactic acidemia, failure to thrive, and isolated complex IV deficiency are presented. We show that the variant lies within the evolutionarily conserved COX5A/COX4 interface domain, suggesting that it alters the interaction between these two subunits during complex IV biogenesis. In patient skin fibroblasts, the enzymatic activity and protein levels of complex IV and several of its subunits are reduced. Lentiviral complementation rescues complex IV deficiency. The monomeric COX1 assembly intermediate accumulates demonstrating a function of COX5A in complex IV biogenesis. A potential therapeutic lead is demonstrated by showing that copper supplementation leads to partial rescue of complex IV deficiency in patient fibroblasts.     

Effectiveness of prolonged use of continuous passive motion (CPM), as an adjunct to physiotherapy,after total knee arthroplasty

Background  

Adequate and intensive rehabilitation is an important requirement for successful total knee arthroplasty.     

Time Series Analysis of Treatment Adherence Patterns in Individuals with Obstructive Sleep Apnea

Background  Adherence to medical recommendations is often suboptimal, making examination of adherence data an important scientific concern. Studies that attempt to predict or modify adherence often face the problem that adherence as a dependent variable is complex and non-normally distributed. Traditional statistical approaches to adherence data may mask individual variability that may guide clinician and researcher’s development of adherence interventions. In this study, we employ time series analysis to examine adherence patterns objectively in patients with obstructive sleep apnea (OSA). Although treatment adherence is poor in OSA, state-of-the-art adherence monitoring allows a comprehensive examination of objective data. Purpose  The purpose of the study is to determine the number and types of adherence patterns seen in a sample of patients with OSA receiving positive airway pressure (PAP). Methods  Seventy-one moderate to severe OSA participants with 365 days of treatment data were studied. Results  Adherence patterns could be classified into seven categories: (1) Good Users (24%), (2) Slow Improvers (13%), (3) Slow Decliners (14%), (4) Variable Users (17%), (5) Occasional Attempters (8%), (6) Early Drop-outs (13%), and (7) Non-Users (11%). Conclusions  Time series analysis provides a useful method for examining adherence while maintaining a focus on individual differences. Implications for future research are discussed.     

丹酚酸A对小鼠脑缺血再灌注致学习记忆功能障碍的改善作用及作用机制

本实验采用脑缺血再灌注损伤造成小鼠学习记忆功能障碍模型。通过跳台和避暗实验法研究了丹酚酸对记忆获得功能障碍的改善作用。结果表明丹酚酸Ａ３，１０ｍｇ·ｋｇ－１ｉｖ可以减轻脑缺血再灌注导致的小鼠学习记忆功能障碍状态。并使小鼠脑缺血再灌注后脑组织中脂质过氧化产物ＭＤＡ含量明显降低。体外实验表明丹酚酸Ａ１０－８～１０－７’ｍｏｌ·Ｌ－１可以抑制大鼠脑组织匀浆脂质过氧化反应和羟自由基（·ＯＨ）的生成，表现出较强的抗氧化作用，提示丹酚酸改善脑缺血再灌注损伤的主要机制可能与其抗氧化作用有关。     

Hepatitis B and C in doctors and dentists in Nigeria

We surveyed a random sample (n = 75) of doctors and dentists at University College Hospital, Ibadan, Nigeria. They were offered anonymous testing for hepatitis B surface antigen (HBsAg), hepatitis Be antigen (HBeAG), antibodies to hepatitis B core antigen (anti-HBc) and to hepatitis C virus (anti-HCV), by enzyme immunoassay. The results suggest a high prevalence of hepatitis B virus (HBV) with a high potential of transmissibility, as well as a high prevalence of HCV infection. The majority of the doctors and dentists use universal precaution for protection against viral hepatitis on < 50% of the occasions when they carry out procedures on their patients. Infection with HBV was associated with type of specialty (surgeons, dentists) and lack of HBV vaccination (p < 0.05). After logistic regression, these factors were independently associated with HBV infection (p < 0.05). Sixty (80%) had not received prior HBV vaccination. Unvaccinated personnel were more likely to be surgeons, dentists, < 37 years of age, and have fewer years of professional activity (p < 0.05). After logistic regression, only fewer years of professional activity remained independently associated with lack of vaccination (p < 0.05). To reduce the occupational exposure of HBV, universal precautions must be rigorously adhered to when the doctors and dentists carry out procedures on their patients, and all health-care workers should be vaccinated with HBV vaccine and the HCV vaccine, when it becomes available.      

Association between gelatinase release and increased plasma membrane expression of the Mo1 glycoprotein

Mo1, a glycoprotein heterodimer (gp 155,95) that functions as an adhesion promoting molecule and as the C3bi receptor of human myeloid cells, is expressed in increased amounts in the plasma membrane after exposure of polymorphonuclear leukocytes (PMNs) to various stimuli. Previous studies have suggested that secondary granules represent an intracellular pool of Mo1 that, upon degranulation, fuse with the plasma membrane resulting in a tenfold increase in surface expression of Mo1. To determine the intracellular location of Mo1, we monitored Mo1 expression by immunofluorescence and compared it to the release of myeloperoxidase (MPO, a marker for the primary granules), vitamin B12 binding protein (B12BP, secondary granules), and gelatinase (gelatinase- containing organelles) following exposure to various stimuli. Human neutrophils stimulated with 20 mmol/L fluoride for 16 minutes exhibited a twofold increase in Mo1 expression and gelatinase release but no enhanced release of primary or secondary granular contents. In a similar fashion, incubation of cells at 37 degrees C for five minutes with 7.5 X 10(-9) to 10(-6) mol/L N-formyl-methionyl-leucyl- phenylalanine (FMLP) resulted in significant increases in both surface Mo1 expression (three- to fivefold) and gelatinase release (five- to eightfold) without significant release of either MPO or B12BP. In addition, both the fluoride and FMLP experiments demonstrated that Mo1 up-modulation alone is not sufficient to activate superoxide (O2-) production. These data indicate that at least one intracellular storage pool of Mo1 is the gelatinase-containing organelles and that their fusion with the plasma membrane results in increased expression of Mo1 on the cell surface.     

Analysis with antiidiotype antibody of a patient with chronic lymphocytic leukemia and a large cell lymphoma (Richter's syndrome)

A murine monoclonal antibody made against an idiotypic determinant (Id) of surface IgM/IgD lambda molecules on chronic lymphocytic leukemia (CLL) cells of a 71-year-old woman was used for clonal analysis by two- color immunofluorescence. The anti-Id antibody identified IgM+/IgD+/lambda+ B cells as the predominant cell type of her CLL clone. In addition, substantial proportions of the IgG and IgA B cells and most of the IgM plasma cells in her bone marrow and blood were Id+. Six years after diagnosis, the patient died of respiratory failure due to infiltration of lungs by malignant cells. Autopsy revealed a dramatic change in the tumor cell morphology. The lungs, hilar nodes, and liver were infiltrated by a diffuse large cell lymphoma admixed with the leukemic cells. By immunohistologic staining these anaplastic lymphoma cells were IgM+/IgD-/lambda+ B cells expressing the same Id noted earlier on the CLL cells. The immunoglobulin gene rearrangement pattern on Southern blot analysis was also the same in leukemic blood cells and in the tissues involved by the lymphoma. Thus, the combination of antiidiotype and immunoglobulin gene analyses in this patient with Richter's syndrome revealed that a CLL clone, seemingly "frozen" in differentiation, was actually undergoing isotype switching, differentiation into plasma cells, and evolution into a rapidly growing and fetal lymphoma.     

Respiratory burst oxidase activation can be dissociated from phosphatidylinositol bisphosphate degradation in a cell-free system from human neutrophils

Activation of the respiratory burst oxidase in cell-free preparations from 32P-labeled neutrophils was compared with changes in levels of radioactively labeled phosphoinositides in the same preparations. With membrane particles, treatment with sodium dodecyl sulfate (SDS) in the presence of cytosol led to activation of the oxidase without an alteration in levels of labeled phosphatidylinositol 4,5-bisphosphate (PIP2) or phosphatidylinositol 4-phosphate (PIP). Conversely, solubilization of the membrane particles with deoxycholate resulted in loss of nearly 98% of the radioactive PIP2 without activation of the oxidase. In this solubilized preparation, the oxidase could subsequently be fully activated by SDS in the presence of cytosol, even though the labeled PIP2 was almost totally depleted. Two PIP2-derived second messengers, diacylglycerol and inositol 1,4,5-trisphosphate, as well as the protein kinase C activator phorbol myristate acetate (PMA), failed to activate the oxidase. These results suggest that in a cell- free preparation from human neutrophils, detergent-mediated activation of the respiratory burst oxidase is independent of changes in the levels of phosphoinositides or phosphoinositide-derived second messengers.     

Protein kinases potentially capable of catalyzing the phosphorylation of p47-phox in normal neutrophils and neutrophils of patients with chronic granulomatous disease

A procedure for uncovering novel protein kinases was used to search for enzymes in neutrophils that may catalyze the phosphorylation of the 47- Kd subunit of the NADPH oxidase system (p47-phox). This component of the oxidase can undergo phosphorylation on multiple sites. The method is based on the ability of renatured kinases to recognize exogenous substrates fixed in gels. We report that neutrophils contain several uncharacterized protein kinases that catalyze the phosphorylation of a peptide substrate that corresponds to amino acid residues 297 through 331 of p47-phox. Some of these enzymes are strongly activated on stimulation of the cells with phorbol 12-myristate 13-acetate (PMA). The results indicate that the phosphorylation of p47-phox in neutrophils may be more complicated than previously appreciated and may involve multiple protein kinases. In addition, we have examined both the renaturable protein kinases and the properties of protein kinase C (PKC) in neutrophils from patients with chronic granulomatous disease (CGD) who are deficient in cytochrome b558. Previous studies have shown that these cells exhibit incomplete phosphorylation of p47-phox on stimulation. In this study, we were unable to detect any alterations in the renaturable protein kinases or PKC in CGD neutrophils that could explain these defects in the phosphorylation of p47-phox.