QSAR modeling and transmission electron microscopy stereology of altered mitochondrial ultrastructure of white blood cells in patients diagnosed as schizophrenic and treated with antipsychotic drugs.

Treatment of patients diagnosed as schizophrenic with antipsychotic drugs (neuroleptics) is known to cause occasional unexplained depletion of white blood cells, especially neutrophil granulocytes. It has been known for many years that neuroleptics can interfere with the mitochondrial respiratory chain in vitro. Because there has been a growing interest recently in mitochondrial targeting of drugs, and since a quantitative structure-activity relationship (QSAR) model that predicts mitochondrial accumulation of neuroleptics has been published, we investigated the effects of neuroleptics on white blood cell mitochondria. Venous blood samples were collected from both patients undergoing treatment with neuroleptics and healthy volunteers. The samples were processed for transmission electron microscopy. The resulting images of white blood cells were analyzed using stereology to compare quantitatively mitochondrial morphology in the patient and control groups. We found that in patients, but not in controls, there was swelling of mitochondria and fragmentation of the mitochondrial cristae. There also were fewer mitochondria in patients than in controls, although due to the swelling of the organelles, the volume density of mitochondria in the two groups was not significantly different. Such changes are typical of a toxic insult. Consequently, it seems plausible that, since schizophrenia is not a disease considered to affect white blood cells per se, these changes probably are due to the medication.     

QSAR modeling and transmission electron microscopy stereology of altered mitochondrial ultrastructure of white blood cells in patients diagnosed as schizophrenic and treated with antipsychotic drugs.

Treatment of patients diagnosed as schizophrenic with antipsychotic drugs (neuroleptics) is known to cause occasional unexplained depletion of white blood cells, especially neutrophil granulocytes. It has been known for many years that neuroleptics can interfere with the mitochondrial respiratory chain in vitro. Because there has been a growing interest recently in mitochondrial targeting of drugs, and since a quantitative structure-activity relationship (QSAR) model that predicts mitochondrial accumulation of neuroleptics has been published, we investigated the effects of neuroleptics on white blood cell mitochondria. Venous blood samples were collected from both patients undergoing treatment with neuroleptics and healthy volunteers. The samples were processed for transmission electron microscopy. The resulting images of white blood cells were analyzed using stereology to compare quantitatively mitochondrial morphology in the patient and control groups. We found that in patients, but not in controls, there was swelling of mitochondria and fragmentation of the mitochondrial cristae. There also were fewer mitochondria in patients than in controls, although due to the swelling of the organelles, the volume density of mitochondria in the two groups was not significantly different. Such changes are typical of a toxic insult. Consequently, it seems plausible that, since schizophrenia is not a disease considered to affect white blood cells per se, these changes probably are due to the medication.     

RAPID SCREENING FOR SALMONELLA IN FISHMEAL BY ENRICHMENT-IMMUNOASSAY

We previously described an enrichment-immunoassay utilizing a T6 monoclonal antibody capture enzyme-linked immunosorbent assay. Here we evaluated it for the rapid screening for Salmonella in fishmeal obtained from the national Animal and Plant Quarantine service in the People's Republic of China. In this method, the number of Salmonella present is first expanded by appropriate enrichment cultures, and the pathogens are then directly detected by the T6 immunoassay. In a total of 94 enrichment cultures of fishmeal, we obtained an overall concordance of 98% between the results obtained in parallel by this method and by conventional test method. The positive prediction by this method was 92% and the negative prediction was 100%. The turn around time for the new test was 27 h which is a significant improvement from the turn around time exceeding 96 h required for the conventional test method. This test proved to be compatible with the routine work flow in the practical setting of a quarantine laboratory.     

The mechanism of covalent reaction of bromoacetyl-phenylalanyl-transfer RNA with the peptidyl-transfer RNA binding site of the Escherichia coli ribosome

Results are presented to prove that bromoacetyl-phenylalanyl-transfer RNA reacts covalently with 50 S ribosomal proteins L2 and L27 while it is bound correctly to the peptidyl site on the 70 S ribosome. Attachment of the BrAcPhe moiety to tRNA causes a 100-fold enhancement of its reactivity with ribosomes. This reactivity closely parallels binding of tRNA whether measured by poly(U) stimulation or competition with deacylated tRNA. BrAcPhe-tRNA can bind correctly to the P site as judged by puromycin releasibility and lack of tetracycline inhibition. Little significant reaction of BrAcPhe-tRNA with L2 and L27 occurs during procedures used to purify and analyze ribosomal proteins. If ribosomes are first incubated with BrAcPhe-tRNA and subsequently treated with puromycin before analysis, little inhibition of the covalent reaction with L2 and L27 is observed. In contrast, a few minor reaction products are markedly suppressed. Covalently attached BrAcPhe-tRNA is still capable of accepting an amino acid from Phe-tRNA or puromycin. The products from this reaction are found attached to proteins L2 and L27 and to a lesser extent to L15 and L16. This shows that true affinity labeling of proteins in the peptidyl binding site has been accomplished.Some covalent reaction of BrAcPhe-tRNA with the 30 S protein S18 is also observed. This reaction is not poly(U)-dependent, however, and S18-reacted BrAcPhe-tRNA is not capable of peptide bond formation with Phe-tRNA. It seems likely that reaction with S18 results from a non-functional interaction of the affinity label with the ribosome.     

Mannose binding lectin plays a crucial role in innate immunity against yeast by enhanced complement activation and enhanced uptake of polymorphonuclear cells

Background  

Mannose binding lectin (MBL) is an important host defence protein against opportunistic fungal pathogens. This carbohydrate-binding protein, an opsonin and lectin pathway activator, binds through multiple lectin domains to the repeating sugar arrays displayed on the surface of a wide range of clinically relevant microbial species. We investigated the contribution of MBL to antifungal innate immunity towards C. parapsilosis in vitro.     

Beware of thermal epiglottis! A case report describing ‘teapot syndrome’

Background

The type of scalding injury known as ‘teapot syndrome’, where hot liquid is grabbed by the child with the aim of ingestion and falls over a child causing burns on the face, upper thorax and arms, is known to cause peri-oral and facial oedema. Thermal epiglottitis following scalds to face, neck and thorax is rare and can occur even in absence of ingestion of a damaging agent or intraoral burns, Awareness of the possibility of thermal epiglottitis, also in scald burns, is imperative to ensure prompt airway protection.

Case presentation

We report the case of a child with thermal epiglottitis after a scalding burn from boiling milk resulting in mixed deep burns of the face, neck and chest, but no history of ingestion. Upon presentation there was a progressive stridor and signs of respiratory distress requiring intubation. Laryngoscopy revealed epiglottis oedema, confirming the diagnosis of thermal epiglottitis. Final extubation took place 5 days after initial burn.

Conclusions

Thermal epiglottitis following scalds to face, neck and thorax is rare and can occur even in absence of ingestion and intra-oral damage. Burns to the peri-oral area should raise suspicion of additional damage to oral cavity and supraglottic structures, even in absence of intra-oral injury or initial respiratory distress. Awareness of the occurrence of thermal epiglottitis in absence of intra-oral injury is important to diagnose impending upper airway obstruction requiring intubation.