Neutrophil superoxide and hydrogen peroxide production in patients with acute liver failure

Defects in superoxide and hydrogen peroxide production may be implicated in the high incidence of bacterial infections in patients with acute liver failure (ALF). In the present study, oxygen radical production in patients with ALF due to paracetamol overdose was compared with that of healthy volunteers. Neutrophils from 14 ALF patients were stimulated via the complement receptors using zymosan opsonized with ALF or control serum. Superoxide and hydrogen peroxide production by ALF neutrophils stimulated with zymosan opsonized with ALF serum was significantly reduced compared with the control subjects ( P  < 0.01). This defect persisted when zymosan opsonized by control serum was used ( P  < 0.05). Superoxide and hydrogen peroxide production in neutrophils stimulated with formyl-methionyl-leucyl-phenylalanine (fMLP) from a further 18 ALF patients was unaffected compared with control neutrophils. Serum C3 complement levels were significantly reduced in ALF patients compared with control subjects ( P  < 0.0005). These results demonstrate a neutrophil defect in ALF due to paracetamol overdose, that is complement dependent but independent of serum complement, possibly connected to the complement receptor.     

Production and Characterization of Monoclonal Antibodies Against the Major Cysteine Proteinase of Trypanosoma cruzi

In the present study we describe the production and characterization of a panel of monoclonal antibodies (MoAbs) directed against cruzipain (Crz), the major cysteine proteinase from Trypanosoma cruzi . The five MoAbs, BD6, BF2, CG2, CH8, and DC10 were analysed with respect to affinity and specificity. None of the MoAbs cross-reacted with papain, which has regions of high homology with Crz. Treatment of the antigen with periodate did not affect the binding of the MoAbs. suggesting that they bind to the polypeptide moiety of Crz. CH8 recognized a continuous epitope located at the C-terminal extension of the proteinase that appeared to be highly immunogenic. Although the rest of the MoAbs recognized epitopes located in the catalytic domain, the enzymatic activity of Crz was not impaired by the binding of the MoAbs. Characterization of the antibody-binding sites revealed the presence of at least four separate epitopes.     

Changing patterns in interventional bronchoscopy

Background and objective:   Many interventional tools for airway disorders can now be delivered via flexible bronchoscopy (FB), including neodymium-yttrium aluminium garnet laser, electrocautery, argon plasma coagulation, cryotherapy, balloon dilatation and metal or hybrid stents. Comparison of outcomes for patients undergoing rigid bronchoscopy (RB) with those treated using FB highlights the usefulness of the FB approach.
Methods:   A retrospective medical record review of all interventional bronchoscopy procedures performed at Lahey Clinic over the past 8 years was conducted. Patients were categorized into two groups according to the procedure used, that is, RB (251 patients), and FB (161 patients) groups. Patients with malignancies were included as a separate subgroup, comprising 178 RB and 117 FB patients. For every procedure, the location of the lesion, patient survival from the first interventional procedure performed, and in patients with malignancy, additional treatments received such as chemotherapy and radiation were recorded.
Results:   Ninety per cent of RB procedures were performed in patients with tracheal or main stem lesions, while over half the patients undergoing FB had more distal lesions. A trend towards increasing use of FB for interventional procedures in recent years was noted.
Conclusions:   FB is a valuable alternative to RB for treating less advanced malignant disease or distal airway lesions.     

Extracorporeal photochemotherapy in a patient with Ki-1-positive anaplastic large-ceil lymphoma

Summary A 57-year-old man with Ki-1 anaplastic large-cell lymphoma treated with extracorporetil photochemotherapy is described.     

Cyclooxygenase-1 and Cyclooxygenase-2 in the Human Optic Nerve Head

To investigate the hypothesis that eicosanoids act as cellular mediators in the optic nerve head of normals and of patients with glaucoma, we have determined the presence of the two cyclooxygenase (COX) isoforms in human tissue. Histological sections of optic nerve heads were studied by immunohistochemistry. Age matched normal donors were compared with eyes from glaucoma patients with moderate to severe nerve damage. Polyclonal antibodies to human COX-1 and COX-2 were localized with immunoperoxidase staining. Specific antibodies for vascular endothelia and microglia were also co-localized. In normal and glaucomatous eyes, COX-1 was localized exclusively to the prelaminar and lamina cribrosa regions of the optic nerve head. No staining for COX-1 was observed in the nerve fiber layer or the myelinated optic nerve. COX-1 was associated with the astrocytes of the glial columns and the cribriform plates, but not with the endothelia lining the capillaries. In glaucoma, more astrocytes appeared to be stained with antibody to COX-1 than in normals and staining was intensely perinuclear. There was no staining for COX-2 in normal tissue. A few COX-2 positive cells were found in the prelaminar, lamina cribrosa and postlaminar regions of the glaucomatous optic nerves. Positive staining for COX-2 was not associated with microglia. COX-1 is constitutively present in astrocytes that are localized exclusively to the prelaminar and lamina cribrosa regions of the human optic nerve head. Eicosanoids, synthesized by COX-1 in this tissue, may have a homeostatic and a neuroprotective role related to the axons of the retinal ganglion cells. The sparse presence of COX-2 in glaucomatous tissue probably reflects the lack of inflammation associated with glaucomatous optic neuropathy.     

SUBACUTE BENZODIAZEPINE TREATMENT: OBSERVATIONS ON BEHAVIOURAL TOLERANCE AND WITHDRAWAL

The acute and subchronic actions of the benzodiazepines triazolam,oxazepam and diazepam have been examined using three behaviouraltests. In the accelerating rotarod motor coordination test bothdiazepam and oxazepam on acute administration produced dose-relateddiscoordination or motor impairment in mice. After chronic administration(50 mg/kg per day i.p. for 14 days) the corresponding dose-responselines were shifted to the right suggesting tolerance development.In a test for conflict behaviour in rats (conditioned suppressionof drinking) oxazepam (20 mg/kg i.p.), triazolam (1 mg/kg i.p.)and diazepam (10 mg/kg i.p.) all augmented punished respondingrates with no effect on unpunished responses and this has beenspeculated to reflect anxiolytic activity. These initial elevationsin punished responding displayed a gradual decline during repeateddaily administration over 20 days, there being little alterationin the unpunished response levels. In separate studies, chronictreatment of mice with triazolam in the drinking water over30 days showed diminished pentylenetetrazol-induced seizurelatencies compared to the level of protection afforded by triazolamat the beginning of the schedule. In additional experiments,mice injected daily with triazolam (1 mg/kg i.p. for 14 days)exhibited a higher seizure susceptibility than their correspondingcontrols. The results are discussed in relation to toleranceto the anxiolytic, anticonvulsant and neurological impairmentproperties of benzodiazepines.     

Hereditary xerocytosis: a report of six unrelated Spanish families with leaky red cell syndrome and increased heat stability of the erythrocyte membrane

Summary. Hereditary xerocytosis (HX) is a rare haemolytic disease due to dehydrated red blood cells (RBCs). A unique feature of this syndrome is that affected members often show normal or near normal haemoglobin levels despite clinical and laboratory evidence of mild to moderate haemolysis. The diagnostic clue is the association of markedly increased RBC Na⁺+K⁺ fluxes with low total cation (Na⁺ +K⁺) content. 11 patients of six unrelated families of Spanish origin with HX have been studied from clinical, genetical and biological points of view. In addition, we have investigated the sensitivity of RBC membrane to heat at three different incubation times (15, 30 and 60min) and two different temperature values (46°C and 49°C). Under these conditions control RBCs (50 normal subjects) exhibited at 49°C and 30min a maximum of 30% fragmented RBCs. This value increased to 80% after 60min of incubation. In contrast, patients with HX showed significantly lower percentages of fragmented RBCs at both 30 and 60min of incubation (maximum 10% and 30%, respectively). In an attempt to determine if increased heat stability was unique to HX RBCs, several other congenital membranopathies with haemolytic anaemia were also studied. The degree of fragmentation, except in one case of HPP (which was strongly increased), did not differ from the control group. Electrophoretic studies of membrane proteins performed in RBCs of all the patients with HX did not explain any qualitative nor quantitative abnormality.
In addition to its physiopathological interest, study of RBC heat stability, together with other haematological parameters (increased MCHC and decreased RBC osmotic fragility), may be useful for HX diagnosis, especially in laboratories which are not equipped to evaluate RBC membrane permeability.