Suppression of the paternal IgA-f and IgA-g allotypes in heterozygous rabbits suppressed for the paternal IgM allotype

The injection of neonatal rabbits of genotype a¹n^{8 1}g^{7 4}/a²n^{8 2}f⁷¹g⁷⁵with anti-n81 antiserum suppressess the expression of the paternal f73 and g74 IgA allotypes; the expression of the maternal 171 IgA allotype is enhanced but the expression of the g75 allotype is not significantly enhanced. The concentrations of these allotypes in serum correlated with the immunofluorescent analyses of cellular ratios in gut sections. Allotype suppression of IgA with an anti-IgM reagent supports the concept that the IgM bearing cells are the precursors of the IgA secreting cells.     

The development of synaptic plasticity induction rules and the requirement for postsynaptic spikes in rat hippocampal CA1 pyramidal neurones

Coincident pre- and postsynaptic activity induces synaptic plasticity at the Schaffer collateral synapse onto CA1 pyramidal neurones. The precise timing, frequency and number of coincident action potentials required to induce synaptic plasticity is currently unknown. In this study we show that the postsynaptic activity required for the induction of long-term potentiation (LTP) changes with development. In acute slices from adult rats, coincident pre- and postsynaptic theta burst stimulation (TBS) induced LTP and we show that multiple high-frequency postsynaptic spikes are required. In contrast, in acute slices from juvenile (P14) rats, TBS failed to induce LTP unless the excitatory postsynaptic potentials (EPSPs) were of sufficient magnitude to initiate action potentials. We also show that coincident individual pre- and postsynaptic action potentials are only capable of inducing LTP in the juvenile when given at a frequency greater than 5 Hz and that the timing of individual pre- and postsynaptic action potentials relative to one another is not important. Finally, we show that local tetrodotoxin (TTX) application to the soma blocked LTP in adults, but not juveniles. These data demonstrate that somatic spiking is more important for LTP induction in the adult as opposed to juvenile rats and we hypothesize that the basis for this is the ability of action potentials in the postsynaptic CA1 pyramidal neurone to back-propagate into the dendrites. Therefore, the pre- and postsynaptic activity patterns required to induce LTP mature as the hippocampus develops.     

Variable clinical presentation of lysosomal beta-mannosidosis in patients with null mutations

Beta-mannosidosis is an autosomal recessive lysosomal storage disease resulting from a deficiency of the lysosomal enzyme beta-mannosidase. The clinical manifestations of this disease in reported human cases are very heterogeneous ranging from relatively mild to moderately severe. This is in contrast with the severe prenatal onset seen in ruminant beta-mannosidosis. In humans, mental retardation, hearing loss, frequent infections, and behavioral problems are relatively common. Dysmorphology and skeletal involvement such as those seen in ruminants are unusual. The purpose of this study is to determine the range of clinical expression in human beta-mannosidosis resulting from null mutations. We determined that the beta-mannosidase gene consists of 17 exons. Intron-based PCR primers were designed and used to amplify each of the exons in genomic DNA isolated from patient fibroblasts. We identified two patients with null mutations. Results of the analysis showed that one patient was heterozygous for nonsense mutations G334T (E83X) in exon 2 and C1363T (Q426X) in exon 10, resulting in truncation of the deduced peptide sequence from 879 to 82 and 425 amino acids, respectively. The second patient was homozygous for a deletion mutation in exon 11 (1541delAT). This deletion causes a reading frame shift and 26 out of frame amino acids before a stop codon occurs in exon 12, resulting in truncation of the deduced peptide sequence from 879 to 510 amino acids. Because disease presentation in these patients with null mutations is very variable, ranging from mild to severe, we conclude that beta-mannosidosis in humans may indeed be milder than typical of other lysosomal storage disorders.     

Co-detection and discrimination of six human herpesviruses by multiplex PCR-ELAHA.

BACKGROUND: Herpesviruses are a significant cause of human morbidity. Traditional approaches to the identification of these viruses require infectious or at least antigenic virus. Multiplex PCR (mPCR) is capable of simultaneously amplifying a range of targets from a single preparation of nucleic acids and when combined with a suitable detection assay, it is capable of discriminating each of the amplicons. OBJECTIVES: Several methods have been described in the literature, however, they lack one or more significant design features required to suitably control a routinely applied nucleic acid amplification assay. We aimed to design a multiplex herpesvirus PCR that could co-amplify eight human herpesvirus targets plus an internal control (IC) molecule in a single tube. STUDY DESIGN: Primers were designed to target the DNA polymerase genes of each of the human herpesviruses. Synthetic controls were developed to act as templates for the evaluation of assay sensitivity and specificity and for development of an in-house competitive quantitative PCR. Amplicon was discriminated using a simplified enzyme linked amplicon hybridisation assay (ELAHA). RESULTS AND CONCLUSIONS: For routine diagnostic use we reduced the number of herpesviral targets from 8 to 6 in order to maintain adequate clinical sensitivity. The ELAHA proved more sensitive than agarose gel electrophoresis. Additionally, 36 cytomegalovirus positive patients were examined with an in-house quantitative PCR-ELAHA which was developed to confirm that that the mPCR's co-detection limit of 10(2) copy of synthetic template per millilitre was relevant for use in detecting virus from clinical samples. The mPCR-ELAHA was then applied to the screening of 174 patient specimens resulting in a specificity of 98% and a sensitivity of 93%. This preliminary study demonstrated that the mPCR-ELAHA was a complete approach to the detection of herpesviruses from a range of clinical samples and disease states.     

Discoid lupus erythematosus at the site of an intradermal injection of killed staphylococcus aureus

A case of chronic discoid lupus erythematosus is described in which there were recurrent relapses following infections, and at the same time repeated `flare ups' at the site of a delayed hypersensitivity reaction to Staphylococcus aureus. The appearance of the injection site changed from that of a typical `tuberculin reaction' to a patch of discoid lypus erythematosus which was confirmed both histologically and by immunofluorescence.     

An investigation into the relationship between salivary cortisol,stress, anxiety and depression

This study examined the relationship between indices of self-reported emotional distress and absolute versus change in cortisol levels. Fifty-four women attending a diagnostic breast clinic completed scales measuring stress, anxiety and depression and provided five saliva samples over the course of a single day for the measurement of cortisol. No significant relationships were evident between absolute cortisol levels and the distress measures. Analysis of the change in cortisol levels revealed a non-linear interaction effect between stress and anxiety and time of day. There was a non-linear relation between time of day and cortisol levels, but the extent of the non-linearity was dependent upon levels of stress and anxiety, not depression. A relationship was apparent between indices of distress and change in cortisol levels, but not absolute levels of the hormone.     

Functional polymers and sequential copolymers by phase transfer catalysis, 27. Synthesis of aromatic-aliphatic polyformals by polyetherification of 1,4-bis(chloromethoxy)butane with 4,4′-isopropylidenediphenol

The first examples of aromatic-aliphatic polyformals were synthesized from 4,4′-isopropylidenediphenol ( 2 ) and 1,4-bis(chloromethoxy)butane ( 1 ) by a two-phase (aqueous NaOH/toluene), phase transfer catalyzed (PTC) polyetherification. The influence of the reaction conditions upon the polymerization was studied by varying the phase transfer catalyst concentration, NaOH concentration and nucleophile to electrophile ratio. Changes in these parameters and their effects upon the microstructure of these polymers were also examined by ¹H NMR (200 MHz) spectroscopy. The reactivity of 1 has permitted, according to our knowledge, the first examples of interfacial polyetherification. Further, this reactivity has also permitted the homopolymerization of 1 through its hydrolysis byproducts under PTC conditions.