Membrane structure, toxins and phospholipase A2 activity.

The phospholipid-hydrolyzing enzyme phospholipase A2 (PLA2) (EC 3.1.1.4) exists in several forms which can be located in the cytosol or on cellular membranes. We review briefly cellular regulatory mechanisms involving covalent modification by protein kinase C and the action of Ca2+, cytokines, G proteins and other cellular proteins. The major focus is the role of phospholipid structure on PLA2 activity, including (1) the mechanism of PLA2 action on synthetic phospholipid bilayers, (2) perturbation of synthetic and cellular membranes with lipophilic agents and membrane-interactive peptides and (3) the ability of these agents to activate endogenous PLA2 activity, with emphasis on the venom and plant toxins melittin, cardiotoxin and Pyrularia thionein.     

Superior vena caval obstruction: a 10-year experience

One hundred and fifty-nine patients with symptoms of superior vena caval obstruction who presented to two major hospitals over a 10-year period, from 1970 to 1979, were reviewed. Lung cancer was the most common histological diagnosis. The most common symptoms were dyspnoea and a feeling of fullness in the head. The most common physical findings were dilatation of the neck or chest wall veins, or oedema of the face and arms. Superior mediastinal widening was the most common radiological abnormality. No significant morbidity was associated with any diagnostic procedure. Only patients with lymphoma had a significantly longer survival period, both from the diagnosis of the disease, and from the onset of the symptoms of superior vena caval obstruction. There is no evidence that superior vena caval obstruction is an absolute medical emergency. Appropriate diagnostic steps should be undertaken to establish the histological diagnosis. The prognosis for some tumour types may be improved by combined modality therapy (chemotherapy plus radiotherapy).     

Predictors of Paternal Versus Maternal Stress in Families of Children With Neural Tube Defects

This study examined the types of stress experienced by maternal and paternal caretakers of children with Neural Tube Defects (NTD) and examined child and family characteristics that correlated with stress. Participants were 71 two-parent families of a child with spina bifida. Parents completed the Parenting Stress Index-Short Form to measure types of stress. Additional measures were completed to investigate variables potentially related to reported stress. Fathers reported significantly higher levels of stress from “dysfunctional parent-child interaction.” Mothers' personal stress correlated with disability and medical characteristics of the child. Fathers reported more stress when the child had maladaptive behaviors and when experiencing fewer social supports and resources. Mothers and fathers coparenting a child with NTD have both common and unique stresses. It is important that both be included in parent support and education initiatives.     

Peripheral blood stem cell autografting

Transplantation of haemopoietic stem cells provides a means whereby patients with malignant disease may be treated with increased doses of chemotherapy or chemoradiotherapy. Until recently, the bone marrow has been the sole source of these cells. However, haemopoietic progenitors can also be demonstrated in the blood and it has been known for more than twenty years that peripheral blood mononuclear cells are capable of repopulating the marrow in animals. This phenomenon has recently been reproduced in man. The use of peripheral blood rather than bone marrow for autologous stem cell rescue may have advantages in terms of ready access, availability in patients with compromised pelvic bone marrows, a lower risk of tumour contamination and more rapid granulocyte and immune recovery. However, clinical experience with peripheral blood stem cell autografting is still very small. This review discusses the characteristics of circulating stem cells, the methods by which they can be collected and stored and the information which has come from recent studies of their transplantation in man.     

Reduced concentration of hepatic alpha-tocopherol in patients with alcoholic liver cirrhosis.

The concentration of alpha-tocopherol was measured in liver biopsy specimens obtained from 83 patients with alcoholic and non-alcoholic liver diseases. The mean hepatic vitamin E content (as alpha-tocopherol) was significantly lower in 23 patients with alcoholic cirrhosis (17.6 +/- 12.1 nmol/mg wet weight liver), compared with 12 patients with normal liver histology (39.2 +/- 29.7 nmol/mg, P less than 0.01). The mean serum concentration of alpha-tocopherol was lower in patients with alcoholic cirrhosis (13.9 +/- 7.0 mumol/l) than in individuals with alcoholic fatty liver (21.3 +/- 9.3 mumol/l, P less than 0.01) and patients with normal liver histology (23.4 +/- 11.6 mumol/l, P less than 0.01). A decreased ratio of serum alpha-tocopherol/total serum lipids was also observed in patients with alcoholic cirrhosis, compared with patients with normal liver histology (P less than 0.05). There was a significant correlation between concentrations of alpha-tocopherol in liver and serum (r = 0.43, P less than 0.001). Furthermore, serum alpha-tocopherol correlated with retinol (r = 0.53, P less than 0.001), selenium (r = 0.45, P less than 0.001), and albumin (r = 0.37, P less than 0.001) in serum. We suggest that the reduced content of hepatic alpha-tocopherol observed in some patients may play a role in ethanol-induced lipid peroxidation.