Profound suppression of cellular proliferation mediated by the secretions of nematodes

Loss of T lymphocyte proliferation and the emergence of a host response that is dominated by a Th2-type profile are well-established features of human filarial infection. Downregulation and modulation of host T cell responses during lymphatic filariasis has been investigated by implantation of parasite stages into inbred mice. Adherent peritoneal exudate cells (PEC) from mice transplanted with adult or larval Brugia malayi parasites are profoundly anti-proliferative but do not prevent antigen-specific cytokine production by T cells. We demonstrate here that the excretory/secretory (E/S) products of the adult parasite are sufficient to induce PEC that block proliferation if injected daily into mice. We have previously shown that in vivo production of host IL-4 is required for the generation of suppressive cells. Because the induction of host IL-4 is characteristic of infection with nematodes, we asked whether E/S from two other nematode parasites, Nippostrongylus braziliensis and Toxocara canis were also capable of generating a suppressor cell population. Injection of E/S from these two parasites also led to a reduction in T cell proliferation suggesting that this mechanism of down-regulating host responses is a feature common to nematode parasites .     

Electrical response audiometry: a survey of its effect on the diagnosis and management of deafness in children

The effect of the use of electric response audiometry (ERA) on the diagnosis and management of children has been investigated. A retrospective method was employed using the notes of the first 102 hearing assessments in 1978 where an ERA test was performed. The results show that the effect on diagnosis has been to improve the degree of certainty rather than to re-classify patients as deaf or normal. The effect on management has been to reduce by 24% the number of patients that require repeat assessment. These effects are more pronounced in the ‘0-1 age group’ as opposed to the ‘above 1 year’ age group.     

Crystallographic characterization of geometry and conformation of TOAC,a nitroxide spin-labelled Cα,α-disubstituted glycine,in simple derivatives and model peptides *

The molecular and crystal structures of one derivative and two oligopeptides of TOAC, a nitroxide spin-labelled C^αα-disubstituted glycine, have been determined by X-ray diffraction. The derivative is the 5(4H)-oxazolone from Piv-TOAC-OH; the oligopeptides are Z-TOAC-(L-Ala)₂-NHtBu sesquihydrate and p BrBz-TOAC-(L-Ala)₂-TOAC-L-Ala-NHtBu hemihydrate. Incipient and fully developed right-handed 3₁₀-helical conformations are formed by both independent molecules in the asymmetric unit of the terminally blocked tripeptide amide and the terminally blocked pentapeptide amide, respectively. The average geometry and preferred conformation for the piperidine ring of the TOAC residues are also discussed in detail. © Munksgaard 1996.     

Can Ultrasound and Computed Tomography Replace High-dose Urography in Patients with Impaired Renal Function?

Ninety-one patients with unexplained impaired renal functionwere investigated by high-dose urography, ultrasound and computedtomography (CT) without contrast. The aim was to evaluate therole of ultrasound and CT in renal failure, in particular theirability to define renal length and to show collecting systemdilatation. In the majority of patients, renal length could be measuredaccurately by ultrasound. Mea surements were less that thoseat urography because of the absence of magnification. Renalmeasurement by CT was not a sufficiently accurate indicatorof renal length to be of clinical use. Both ultrasound and CT were sensitive detectors of collectingsystem dilatation: neither technique missed any case diagnosedby urography. However, in the presence of staghorn cal culior multiple cysts, neither ultrasound nor CT could exclude collectingsystem dilatation. CT was the only technique which demonstrated retroperitonealnodes or fibrosis causing obstruction. It is proposed that the first investigation when renal functionis impaired should be ultrasound, with plain films and renaltomograms to show calculi. CT should be reserved for those patientsin whom ultrasound is not diagnostic or in whom ultrasound showscollecting system dilatation but does not demonstrate the cause.Using this scheme, ultrasound, plain radiography and CT wouldhave demonstrated collecting system dilatation and, where appropriate,shown the cause of obstruction in 84 per cent of patients inthis series. Only 16 per cent of patients would have requiredeither high-dose urography or retrograde ureterograms.     

CARBON-DIOXIDE ELIMINATION DURING CLOSED CHEST CARDIAC MASSAGE

Acid-base balance was accurately measured before, during andafter external cardiac massage in a case of ventricular fibrillationdeveloping shortly after induction of anaesthesia for herniorrhaphy.Results showed that the acidosis which occurred during cardiacarrest was purely metabolic in origin, and that carbon dioxideelimination by the lungs during intermittent positive pressurerespiration in a patient undergoing external cardiac massagewas sufficient to lower the Pco₂ below normal. The managementof the case is described.     

Effects of Anticonvulsant Drugs on the Synthesis of DNA and Protein by Human Bone Marrow Cells in Vitro

Suspensions of human bone marrow cells were incubated with various concentrations of phenobarbitone or phenytoin sodium for 2 h, and the effects of this incubation on the subsequent incorporation of ³H-thymidine and ³H-leucine into DNA and protein, respectively, were studied. Both drugs caused a depression of ³H-thymidine incorporation and this phenomenon was not prevented by the addition of 100 μg of pteroylglutamic acid, folinic acid or 5-methyltetrahydrofolate per ml of marrow culture. The lowest concentration of drug which caused a statistically significant depression of ³H-thymidine incorporation was 200 μg per ml for phenobarbitone and 50 μg per ml for phenytoin sodium. Both phenobarbitone and phenytoin sodium also caused an increase in the incorporation of ³H-leucine at concentrations of 50 and 20 μg per ml, respectively, suggesting the possibility that a stimulation of protein synthesis within erythropoietic cells may play an important role in the development of anticonvulsant-induced macrocytosis.