Effects of the amphiphilic peptides melittin and mastoparan on calcium influx, phosphoinositide breakdown and arachidonic acid release in rat pheochromocytoma PC12 cells.

Two amphiphilic peptides from hymenopterid insects, melittin and mastoparan, stimulate secretion in a variety of cell types. In PC12 cells, both peptides stimulate calcium influx with melittin some 20-fold more potently than mastoparan. Melittin stimulates both breakdown of phosphoinositides (Pl) by phospholipase C to yield inositol phosphates and hydrolysis of phospholipids by phospholipase A2 to release arachidonic acid (AA). Mastoparan stimulates Pl breakdown, but has no effect on AA release. Maximal stimulation of Pl breakdown occurs at 1 to 2.5 micrograms/ml melittin and 30 micrograms/ml mastoparan, whereas maximal stimulation of AA release occurs at 2 to 5 micrograms/ml melittin. Organic calcium channel blockers (nifedipine, verapamil, diltiazem) have little or no effect on responses to the peptides. The influx of calcium elicited by melittin or mastoparan is completely or nearly completely blocked by inorganic calcium channel blockers (Co++, Mn++, Cd++). Mn++ and Cd++ inhibit melittin-induced Pl breakdown and AA release and mastoparan-induced Pl breakdown. Co++ has no effect on melittin-induced Pl breakdown and potentiates mastoparan-induced Pl breakdown. Pertussis toxin has no effect on the Pl breakdown induced by either peptide. The responses to melittin and mastoparan in PC12 cells are compared to those reported for maitotoxin.     

Immobilization of Aspergillus fumigatus colonies in a soft agar matrix allows visualization of A549 cell detachment and death.

A model to examine the effects of proliferating Aspergillus fumigatus ATCC 26933 colonies embedded in a thin layer of soft agar on a monolayer of A549 cells was developed and enabled an investigation of the response of cultured cells to fungal growth. This model simulates the conditions on the respiratory surface in patients with invasive aspergillosis and also in the mucus secretions of cystic fibrosis patients with allergic bronchopulmonary aspergillosis. Conidia of A. fumigatus adhering to A549 cells were immobilized in a thin layer of soft agar (0.6% (w/v)) and allowed to germinate at 37 degrees C. Fungal colonies greater than 5 mm in diameter caused rounding-up and detachment of A549 cells underneath the colony and towards the hyphal tips. As the fungal colony diameter increased, cell detachment occurred ahead of the hyphal tips. Cells detached for short periods (less than 6 h) showed no annexin-V (AV) or propidium iodide (PI) staining, suggesting no externalization of phosphatidylserine and an intact plasma membrane. Cells that had detached for periods greater than 6 h were positive for AV and PI indicating the rupture of the plasma membrane and cell death by necrosis. Chemical extraction and separation by thin layer chromatography of agar from zones of cell detachment around fungal colonies revealed the presence of three compounds that may play a role in inducing cell death.     

Benign mesenchymoma of the palate: report of a case

A case of benign mesenchymoma of the hard palate is presented. The lesion was completely excised and the tumor margins were shown to be free of disease. Within 4 months a second noncontiguous lesion arose of the opposite side of the palate and was also removed. Whether this represented a distinctly new lesion or possibly one which was seeded through previous diagnostic efforts was difficult to ascertain. Follow-up for more than 2 years has not revealed any further evidence of neoplasia.     

Cytomegalovirus Disease in High-Risk Transplant Recipients Despite Ganciclovir or Valganciclovir Prophylaxis

The clinical patterns and predictors of cytomegalovirus (CMV) disease in kidney and/or pancreas transplant patients on ganciclovir (1.0 g po t.i.d.) or valganciclovir (450 mg po q.d.) prophylaxis were studied. This is a retrospective analysis of 129 transplant recipients. Median follow up was 12 months (range, 6-18 months). The overall incidence of CMV disease at 1-year post-transplant was 14% (4% tissue-invasive, 10% noninvasive). Seventeen of 18 patients were diagnosed with CMV after completion of 3 months' prophylaxis (median 8 weeks, range, 2-28 weeks). Induction treatment with thymoglobulin, and Donor +/Recipient - CMV status were the strongest predictors for the development of CMV disease. Cytomegalovirus incidence was not different between patients treated with ganciclovir or valganciclovir (15 vs. 17%, respectively). Valganciclovir (450 mg q.d.) is as effective as oral ganciclovir in CMV prophylaxis. High-risk individuals might require higher doses or longer duration of valganciclovir treatment.     

The homograft department.

Perfusionists are highly skilled professionals providing essential life support, enabling patients to undergo open heart surgery. Although this is the main function at the Royal Liverpool Children's Hospital, Alder Hey, they also manage a Homograft bank. Also known as a heart valve bank, this is a completely independent branch of the perfusion department.     

Extracranial approaches to the repair of cerebrospinal fluid rhinorrhea.

This paper presents a review of the extracranial evaluation and treatment of cerebrospinal fluid (CSF) rhinorrhea. Diagnosis with attention to a careful history and physical with maneuvers which exacerbate drainage and thorough physical exam along with imaging techniques are discussed. The common etiologies of CSF rhinorrhea including trauma, spontaneous leakage, tumor, and iatrogenic injury are included. Management consists of conservative measures including the avoidance of straining maneuvers which increases intracranial pressure. Periodic drainage of CSF via lumbar puncture or continuous drainage via flow-regulated systems may also be of benefit in attempts of conservative management. Failure of conservative management, constant leakage, pneumocephalus, and recurrent meningitis are indicators for surgical repairs. Ethmoid-cribiform plate region repairs are generally approached by external ethmoidectomy and the development of mucoperiosteal flaps from various donor sites which are then rotated to the leak area to seal the defect. Frontal sinus leaks are usually repaired via an osteoplastic flap technique with direct repair of the dural defect or the use of fascial graft tucked under the bony defect, then obliterated with abdominal fat. CSF rhinorrhea presents a diagnostic and surgical challenge to the otolaryngologist. After diagnosis and localization, operative repair using extracranial approaches is accepted as the initial method of intervention in these cases.     

Diet and disadvantage: observations on infant feeding from an inner city

Background: There are few detailed nutritional studies analysing dietary intakes and weaning practices of inner city infants aged 0–12 months. Pasteurized cow's milk (PCM) is not recommended as a main drink until after 1 year of age, although early usage is still common. Premature introduction of pasteurized cow's milk is associated with increased risk of iron deficiency anaemia. Methods: We therefore prospectively examined the dietary effect of early introduction of pasteurized cow's milk on the nutritional intake of 100 infants (mean age at recruitment 7.8 months), whose mothers had already elected to introduce cow's milk before the recommended age of 12 months in a deprived inner city area. In addition, a retrospective questionnaire on feeding practices and food choices was administered and information on parental education and employment was collected, together with a 3-day dietary diary of weighed intakes at recruitment. Results: The results indicate that weaning practices are handed down from family and friends and are intuitive rather than informed. Over 80% of the infants had intakes of iron, zinc and vitamin D below the reference nutrient intake (RNI) and a further 41% had low vitamin C intakes. Prior to introduction of PCM, there was also misuse of infant formula. Twenty per cent added an extra scoop of powder to the feeds, 10% added milk powder to the bottle before addition of water and 30% used microwave ovens to heat the infant bottle. Conclusion: Feeding practices in a deprived inner city area differed substantially from guidelines and infants were at risk of developing nutrient deficiencies as well as poor feeding practices.