STUDIES ON ANTIBODY PRODUCTION : XIII. THE EFFECT OF CHLORAMPHENICOL ON PRIMING IN MICE

Young adult mice were primed with 20 Lf (56 µg) of diphtheria toxoid and given a second injection of the same size 40 days later. This procedure produces a reproducible secondary response which can be used as a standard. Chloramphenicol in maximum dosage prevents the unknown process by which the animal is primed for the second response. To be fully inhibitory, the drug must be given from the hour of the first antigen injection in maximum dosage for 2 weeks. A delay of 48 hours in starting the drug allows completion of the priming process, and shorter delays produce partial inhibition. Hence the initiation of priming is a rapid process sensitive to chloramphenicol. Subsequent changes in the cell population necessary for the full development of priming are not sensitive to chloramphenicol. The secondary antibody response is not inhibited in mice by chloramphenicol at the doses employed.     

The effect of perinatal undernutrition on perineurial diffusion barrier to exogenous protein

Summary The maturation of the perineurial diffusion barrier to exogenous protein was studied fluorescence-microscopically on sciatic nerve in normal, undernourished and rehabilitated rats. Bovine albumin labelled with Evans blue was used as tracer and applied around the sciatic nervein vivo for 1 h and for 24 h.It was shown that in normal rats the perineurial diffusion barrier to protein is established at the age of 4 weeks and after this age no diffusion through the perineurium into the endoneurial spaces takes place.In rats subjected to pre- and postnatal undernutrition no effective barrier was present during the observation-period extended to 4 months, indicating an impaired maturation of the perineurial diffusion barrier.Rats rehabilitated by foodad libitum, even from the early age of 5 days, revealed no effective barrier to protein when examined at the age of 3 months. It is concluded that pre-and postanatal undernutrition causes a damage to the perineurium functionally manifested as a deficient barrier to exogenously applied protein.     

Cortical perfusion assessment with 123I-isopropyl amphetamine (123I-IAMP) in normal pressure hydrocepha lus (NPH)

NPH can be reversible after cerebrospinal fluid (CSF) diversion. In the past no reliable criteria could be defined to predict the successful outcome of CSF shunting. Several authors demonstrated an increased cerebral blood flow after lumbar puncture in patients with NPH, indicating an underlying impairment of cerebral circulation autoregulation. ¹²³I-AMP brain tomoscintigraphy was applied to 23 individuals with NPH before and after CSF drainage. Of these 23 patients, 10 underwent surgical shunting. The frontal and parietal hypoactive cortical pattern was present in NPH but not pathognomonic. Under stimulation of CSF pressure lowering, seven patients with improved outcome after shunting demonstrated an increase of cerebral perfusion in these areas, whereas a decrease of activity was found in three patients whose clinical status was unchanged after CSF diversion. This tomoscintigraphic test may be an interesting additional criterion for surgical admission.     

Mifepristone (RU486) and therapeutic late pregnancy termination: a double-blind study of two different doses

An antiprogesterone, mifepristone (RU486), was administeredto 35 patients undergoing a therapeutic interruption of pregnancyduring the second and third trimester for maternal or fetalindications. A randomized double-blind study test was perfonnedusing 150 and 450 mg of mifepristone as pretreatment prior toprostaglandins. No toxicity or maternal morbidity were recorded.In three patients the onset of labour occurred spontaneouslybefore prostaglandin administration. Mifepristone produced amodification in the consistency of the cervix with a statisticalimprovement in cervical calibration in the two groups, but thecervical effect was independent of the dose.     

Genetics: Preimplantation diagnosis for X and Y normality in embryos from three Klinefelter patients

In some 47,XXY Klinefelter patients without evidence of mosaicism,testicular spermatozoa can be successfully recovered and usedfor intracytoplasmlc sperm Injection (ICSI). To ensure the replacementof embryos with a normal X and Y chromosome pattern, preimplantationdiagnosis can be performed. This paper reports on three 47,XXYKlinefelter patients from whom it was possible to retrieve testicularspermatozoa in order to perform ICSI. From their healthy wivesa total of 27 oocyte-cumulus complexes were retrieved from which22 metaphase-II oocytes were obtained and injected; 19 of thesewere intact after injection. Two distinct pronuclel were observedin eight oocytes (42.1%) 18 h after injection. On day 3 of development,five embryos (62.5%) had reached at least the 6-cell stage andwere of sufficient quality to undergo biopsy and subsequentpreimplantation diagnosis for sex chromosome analysis by fluorescentin-situ hybridization. The four embryos diagnosed as normalwere transferred to three respective patients, resulting Inone biochemical pregnancy. The remaining cells of the fifthembryo were analysed afterwards, revealing a normal X and Ychromosome constitution. So far, in the five embryos diagnosed,a normal sex chromosome pattern has been observed.