Effect of age on burst firing characteristics of rat hippocampal pyramidal cells.

During behavior, hippocampal pyramidal cells emit high frequency bursts, modulated by the animal's location and the 7 Hz theta rhythm. During rest, CA1 EEG exhibits large irregular activity (LIA), containing sharp-wave/ripple complexes, during which pyramidal cells exhibit burst discharge. Aging results in altered intracellular calcium homeostasis, increased electrical coupling and reduced cholinergic modulation within CA1, all of which might affect burst discharge characteristics.

Two crystalline modifications of 2-hydroxycyclopent-2-enone.

The orthorhombic form of 2-hydroxycyclopent-2-enone, C(5)H(6)O(2), consists of chains of hydrogen-bonded molecules aligned along a twofold screw axis. The monoclinic form contains two independent molecules, which have different orientations of the hydroxyl proton, and which assemble into ribbons along a twofold screw axis.

Kinetic characterisation of ene-diol-based inhibitors of alpha-amylase.

A kinetic analysis of the inhibition of malt alpha-amylase by compounds based on ascorbic acid has shown the mode of inhibition to be competitive for the parent compound, but more complex for its derivatives. We have further simplified the ascorbic acid ene-diol pharmacophore by demonstrating that dihydroxyfumaric acid is also a good inhibitor of malt alpha-amylase.

Suppression of lymphocyte mitogenesis by tamoxifen: studies on protein kinase C, calmodulin and calcium.

The effect of tamoxifen (TX; 1.0 microM) on the mitogenic response of rat lymphocytes was compared with the effect of drugs that are known to act on protein kinase C (PKC), calmodulin (CM), and calcium (Ca(2+)). The calcium ionophore A23187 (0.

Covalent protein adduct formation and protein cross-linking resulting from the maillard reaction between cyclotene and a model food protein.

Covalent Maillard products of the reactions of carbonyl compounds with proteins are often described in the literature, but, until recently, evidence for their existence has been indirect. Cyclotene (2-hydroxy-3-methylcyclopent-2-enone), a common flavor compound, was incubated with a model food protein, ribonuclease, and found to cross-link the protein. Size exclusion high-performance liquid chromatrography and electrospray mass spectrometry of the early stages of the reaction provide strong evidence for covalent adducts that we believe to be intermediates in the cross-linking reaction.

Isolation, identification, and molecular characterization of strains of Photorhabdus luminescens from infected humans in Australia.

We describe the isolation of Photorhabdus (Xenorhabdus) luminescens from four Australian patients: two with multiple skin lesions, one with bacteremia only, and one with disseminated infection. One of the patients had multiple skin lesions following the bite of a spider, while the lesions in the other patient were possibly associated with a spider bite. The source of infection for the remaining two patients is unknown.

Plasma phospholipid fatty acids in the central Canadian arctic: biocultural explanations for ethnic differences.

As part of the Keewatin Health Assessment Study, a comprehensive health interview and examination survey of Inuit and non-Inuit in the central Canadian Arctic during 1990-91, plasma samples were analyzed for phospholipid fatty acid composition. Compared to non-Inuit, the Inuit have reduced levels of dihomo-gamma-linoleic (DGLA) and arachidonic acid (ratios of 0.41 and 0.

Ascorbic acid-based inhibitors of alpha-amylases.

A series of ascorbic acid and isoascorbic acid derivatives has been evaluated as inhibitors of malt, bacterial, fungal, pancreatic and salivary alpha-amylases using a simple and quick assay procedure. The results demonstrate that the enediol moiety of ascorbic acid is essential for alpha-amylase inhibition. Acylation of the primary and secondary alcohols, and the absolute configuration of the secondary alcohol, do not affect the potency of inhibition.

Fatal encephalitis and meningitis at the Gold Coast Hospital, 1980 to 1996.

The recent association of a fatal human case of encephalitis with a newly identified lyssavirus apparently acquired from a native Australian bat has highlighted the possibility that previous human infections have passed urecognised. Infected bats have been identified on the Queensland Gold Coast where extensive close contact between bats and humans has occurred for many years. In an attempt to identify nervously unrecognised cases of fatal lyssavirus encephalitis, the medical records of the Gold Coast Hospital over a 16 years period from 1980 to 1996 were reviewed.

Deciphering the hippocampal polyglot: the hippocampus as a path integration system.

Hippocampal 'place' cells and the head-direction cells of the dorsal presubiculum and related neocortical and thalamic areas appear to be part of a preconfigured network that generates an abstract internal representation of two-dimensional space whose metric is self-motion. It appears that viewpoint-specific visual information (e.g.

Zinc inhibition of electron transfer: mechanism of beta receptor inhibition?

Zinc has been shown to inhibit β-receptor activation of adenylate cyclase at a post receptor site. We have postulated that the β-receptor is one of several receptors activated by reduction, followed by transmembrane elector transfer accelerated by GTP. GTP accelerates electron transfer in a model system and this accelerated electron transfer is inhibited by zinc.

Variability in scoring the Hachinski Ischaemic Score.

Multi-infarct dementia (MID) may be the second most common form of dementia in later life. A commonly used aid in the clinical diagnosis of MID is the Hachinski Ischaemic Score (HIS). The usefulness of this score is controversial, and we hypothesized that this is because many items of the HIS are open to a wide range of interpretations.

Pneumocystis carinii pneumonia in HIV-negative immunocompromised adults.

Objectives: To identify patient populations at risk of Pneumocystis carinii pneumonia (PCP) and assess the potential role of chemoprophylaxis.

Methods: Review of cases of PCP among patients admitted to a tertiary referral hospital in Sydney between January 1990 and April 1993. Cases were identified by indirect immunofluorescent antibody microscopy performed on respiratory tract specimens.

Phenylketonuria revisited.

This article describes the parts played by Bickel, Hickmans, Gerrard, and Woolf in the preparation of a formula low in phenylanine and in the treatment of the first child with phenylketonuria (PKU) with a low phenylalanine diet. As the child whom they were treating was 2 years old, and was already appreciably retarded mentally, the apparent improvement in her mental status was ascribed, by their medical colleagues, to the extra attention that the child was receiving and not to the biochemical changes noted in her blood.

Familial resemblance for immunoglobulin levels.

The familial resemblance for immunoglobulin A, D, E, G, and M levels was investigated with family data collected in Canada and the U.S., entertaining both multifactorial and single gene hypotheses.

Granulophysin is located in the membrane of azurophilic granules in human neutrophils and mobilizes to the plasma membrane following cell stimulation.

Granulophysin, a protein described in platelet dense granule membranes, has been shown to be similar or identical to CD63, a lysosomal membrane protein. We have previously shown granulophysin to be present in neutrophils using immunofluorescence. We now localize granulophysin to the neutrophil azurophilic granules by fine structural immunocytochemistry.

Neuropharmacological evaluation of movement disorders that are adverse reactions to specific foods.

Three cases are reported of patients who had episodic movement disorders triggered by foods or components of the diet. In the first patient, the movement consisted of shaking the head from side to side that was triggered by milk and a number of other foods. In the second patient, the movement consisted of a repeated shrugging of the shoulders that was triggered by egg and coffee.

Australia's first case of AIDS? Pneumocystis carinii pneumonia and HIV in 1981.

Objective: To present the earliest Australian case of the acquired immunodeficiency syndrome (AIDS) reported to date.

Clinical Features: A 72-year-old man developed a prolonged illness, beginning in February 1981, characterised by anorexia, malaise, weight loss and an episode of herpes zoster. In July he noted the insidious onset of dyspnoea with a productive cough.

The empty sack syndrome: a platelet storage pool deficiency associated with empty dense granules.

Two sisters with lifelong bleeding tendencies were examined to determine whether their condition was associated with a platelet defect. Their platelet aggregation in response to epinephrine and collagen was abnormal, and the secretion of serotonin and ATP was markedly reduced. The platelet contents of serotonin, ADP, and ATP were all diminished and the ATP:ADP ratio was increased.

Platelets from bleeding Simmental cattle mobilize calcium, phosphorylate myosin light chain and bind normal numbers of fibrinogen molecules but have abnormal cytoskeletal assembly and aggregation in response to ADP.

We have evaluated platelet function in normal Simmental cattle and in those with a congenital, inherited bleeding disorder previously attributed to impaired platelet aggregation. Affected platelets failed to aggregate and secrete in response to ADP and the ionophore A23187, and showed impaired aggregation responses to collagen and ionomycin. Aggregation and secretion of normal and affected platelets was similar in response to thrombin and PMA.

Post-receptor events associated with thrombin-induced platelet activation.

Thrombin is by far the most potent platelet agonist. Potentially this reflects multiple intracellular processes involved in transmitting the activation signal from the initial contact with a receptor, or binding site, to the final platelet response. Platelet membranes have two putative receptors: the high affinity glycoprotein Ib, whose function remains to be clarified, and the moderate affinity autoproteolytic receptor.

Possible mechanisms of epinephrine actions in quin-2-loaded platelets refractory to arachidonic acid.

We evaluated the effect of Quin-2 loading (> 20 microM) on platelet responses such as phosphoinositide turnover, elevation of cytosolic Ca2+, phosphorylation of myosin light chain (MLC) and a 47-kDa protein, and aggregation in human platelets stimulated with arachidonic acid (AA) and epinephrine. The formation of inositol phosphates (IP, IP2, and IP3) in platelets stimulated with AA was inhibited by 50.4, 59.

A trainer's perspective of an innovative programme teaching health visitors about the detection, treatment and prevention of postnatal depression.

Health visitors in North Staffordshire, Edinburgh and Lewisham were given the opportunity to participate in a training programme in the detection, treatment and prevention of postnatal depression, based on previously reported successful intervention strategies. They were trained in the use of the Edinburgh Postnatal Depression Scale (EPDS), and given information about the value and practice of non-directive counselling and about preventative strategies. Knowledge acquisition was evaluation by self-report questionnaires given before and after training.