Low-frequency stimulation of the perforant path produces long-term potentiation in the dentate gyrus of unanesthetized rats

Brief periods of high-frequency stimulation of hippocampal afferents produce long-term potentiation (LTP) of synaptic transmission, but the minimum frequency capable of inducing this alteration in synaptic efficacy has not been specified. The present study used the repeated measurement of input-output curves in the perforant path - dentate gyrus system of freely moving rats to monitor synaptic efficacy and found that stimulation at 0.2 Hz, but not 0.04 Hz produced LTP. These results suggest that the minimum stimulation frequency capable of producing LTP is lower than previously described. Possible reasons for the discrepancy between the present and previous findings are discussed, along with the implications of low-frequency potentiation.

Translocation of zinc from vacuole to nucleus during yeast meiosis

A novel staining procedure employing the UV fluorochrome DAPI (4',6-diamidino-2-phenylindole X 2HCl) and dithizone (diphenylthiocarbazone) was developed for microcytochemical determination of sites of zinc localization in Saccharomyces cerevisiae Hansen. In vegetative cells vacuolar polyphosphate bodies stained with dithizone, whereas in sporulating cells nucleoli and centriolar plaques were dithizone-positive. Hence, dithizone not only permitted localization of zinc but also indicated zinc translocation from vacuolar to nuclear compartments during differentiation from the vegetative to sporulated state.

Hearing loss in patients with diabetic retinopathy

With use of standard audiometric procedures, the hearing thresholds of patients with known diabetic retinopathy did not differ significantly from those of a control population group. However, use of a more subtle psychoacoustic tool--a filtered speech task--showed a definite difference in hearing acuity between the two groups.

Events associated with restoration by zinc of meiosis in apomictic Saccharomyces cerevisiae

The effects of nutritional alterations (carbon source and zinc) on nuclear division and protein synthesis during apomictic and meiotic development in Saccharomyces cerevisiae 19e1 were investigated. Unlike cells cultivated under meiosis-promoting conditions, cells cultured under apomixis-promoting conditions exhibited extensive protein synthesis during the first 3 h of incubation in sporulation medium, and nuclear divisions were evident during this time. Cycloheximide treatment of the latter cells induced meiosis, and maximum yields of meiotic asci resulted when this treatment was given for the first 3 h in sporulation medium. The results indicate that the decision concerning which developmental route cells will follow is made shortly after transfer to sporulation medium. Electrophoretic analysis of labeled proteins synthesized during sporulation revealed bands unique to both developmental routes.

Role of norepinephrine in seizurelike activity of hippocampal pyramidal cells maintained in vitro: alteration by 6-hydroxydopamine lesions of norepinephrine-containing systems

Perfusion of 50 microM norepinephrine (NE) produced a marked, reversible decrease (range 20-28%) of the extracellular population spike and excitatory postsynaptic potential (EPSP) responses of the CA1 region evoked by stratum radiatum stimulation in the rat hippocampal slice preparation. The effects of NE were dramatically altered in slices obtained from animals which were previously treated with intracerebral or intraventricular injections of 6-hydroxydopamine (6-OHDA) to destroy forebrain catecholamine systems. In the latter preparations NE produced a reduction in the inhibition of the EPSP (50%), enhancement of the population spike amplitude, and multiple spike discharges characteristic of ongoing epileptiform activity. The reversal of NE-induced inhibition and the generation of seizurelike activity in 6-OHDA-treated animals suggests that NE may, in part, act upon interneurons to produce a disinhibition of CA1 pyramidal cells.

An evaluation of high-frequency audiometry suitable for routine clinical use

The evaluation of high-frequency thresholds above 8 kHz has not always been accepted as a reliable, reproducible measure in routine audiological clinics. Using standard equipment we have shown that thresholds at 10 kHz and 12 kHz can be so measured, and that 16 kHz thresholds may be determined with the same degree of reliability with only the minor addition of a signal generator and a set of high performance earphones.

Immunohistochemical localization of calcium-binding protein in the cerebellum, hippocampal formation and olfactory bulb of the rat

The immunohistochemical localization of calcium-binding protein (CaBP) in the cerebellum, hippocampal formation and olfactory bulb of the rat was examined using rabbit anti-human or sheep anti-chick antisera purified by affinity chromatography. CaBP-like immunoreactivity was observed within the somata and dendrites of: (1) cerebellar Purkinje cells; (2) dentate granule cells, CA1 pyramidal cells and scattered interneurons in the stratum radiatum of the hippocampus; (3) periglomerular cells in the olfactory bulb. Staining was conspicuously absent in certain major cell types in each of these structures including cerebellar granule cells, hippocampal pyramidal cells in the CA3 region and both mitral and granule cells in the olfactory bulb. Immunoreactive fibers in the cerebellum presumably corresponding to climbing fiber inputs from the inferior olive and efferent projections to the deep cerebellar nuclei, were also observed. In the hippocampus intense staining was present in the mossy fiber projection to the CA3 region and in the terminal regions of the perforant path projection from entorhinal cortex.

Frequencies of Epstein-Barr virus-inducible IgM anti-IgG B lymphocytes in normal children and children with juvenile rheumatoid arthritis

The relative frequencies of IgM antiIgG autoantibody (rheumatoid factor) producing cells induced by the polyclonal B cell activator Epstein-Barr virus were measured in peripheral blood lymphocyte cultures of normal children and patients with juvenile rheumatoid arthritis. The frequencies of rheumatoid factor precursor B cells in normal children were lower than adults, but higher than neonates. The frequency increased with the age of the donor. In seronegative children with the systemic-onset or pauciarticular-onset types of juvenile rheumatoid arthritis, the number of IgM antiIgG inducible B cells was not significantly different (P greater than 0.05) from age-matched controls. Patients with seropositive juvenile rheumatoid arthritis or seropositive adult rheumatoid arthritis had significantly higher IgM antiIgG precursor cell frequencies than age-matched normal subjects (P less than 0.01 and P less than 0.02, respectively). In contrast, the patients with seronegative polyarticular-onset juvenile rheumatoid arthritis had an average precursor frequency significantly lower than normal age-matched controls (P less than 0.05), analogous to results previously noted in adult seronegative rheumatoid arthritis. Thus, both children and adults with seronegative polyarticular rheumatoid arthritis had a deficiency in B cells that produce IgM antiIgG and that are induced by Epstein-Barr virus. This distinguished them from seropositive juvenile rheumatoid arthritis and rheumatoid arthritis patients, normal subjects, and patients with the pauciarticular-onset and systemic-onset types of seronegative juvenile rheumatoid arthritis.

Calcium-induced long-term potentiation in the hippocampus

The effect of a transient increase in extracellular calcium concentration on the Schaffer collateral-commissural evoked excitatory postsynaptic potential and population spike responses of CAI pyramidal neurons was investigated using the rat in vitro hippocampal slice preparation. Brief exposure of slices (5-10 min) to twice the normal concentration of calcium (4 mM) induced a marked potentiation of both the excitatory postsynaptic potential and population spike that could persist for at least 3 h. No long-term changes were observed in either the presynaptic fiber volley of antidromically evoked CAI population spike, indicating that the potentiation could not be attributed to an increase in the number of fibers activated or a generalized increase in cellular excitability. The response of CAI pyramidal neurons to the iontophoretic application of L-glutamate in the apical dendritic zone was also unaffected after exposure to high calcium perfusate, suggesting a lack of alteration in membrane excitability or receptor sensitivity restricted to the region of synaptic input. In addition, total intracellular calcium content of individual slices, measured by atomic absorption spectrophotometry, was significantly increased for at least 1 h following return to the control medium. These data indicate that brief exposure of in vitro hippocampal slices to a high extracellular calcium concentration results in a long-term increase in synaptic efficacy which is similar in many respects to long-term potentiation induced by tetanic stimulation of hippocampal excitatory afferents. The results further suggest that the mechanisms underlying calcium-induced long-term potentiation may reside in presynaptic components and involve an enhanced transmitter release.

Calcium-binding protein distribution in the rat brain

The distribution in the rat brain of a protein with properties similar to vitamin D-dependent calcium binding protein (CaBP) was measured using a radioimmunoassay developed for mammalian brain CaBP. The cerebellum contained very high levels of CaBP in agreement with reports of CaBP distribution in the chick brain. The protein was distributed in large and unequal concentrations in different regions of the brain. Microdissection of the hippocampus revealed that, within a particular region, CaBP can have a marked differential distribution, suggesting that it is found in specific cell types. The significance of this protein is discussed in relation to the important functions of calcium in the CNS with particular emphasis being placed upon the possible role of CaBP as an intraneuronal calcium ion buffering system.

The social function of young adults who had arthritis in childhood

One hundred twenty-one young adults 18 years of age or older who had been seen at this hospital with juvenile arthritis since 1955 were surveyed by a series of questionnaires to determine current social function and financial status. Chart reviews and patient questionnaires were used to determine modes of onset and the social circumstances of the family at the onset of the arthritis. The patients as a whole were functioning well: 45 were working full time, 25 were in school full time, 23 were in school and working, and 14 were married women at home. Females had a higher prevalence of persisting disability. Patients who had had a polyarticular onset had lower monthly salaries. No other disease or social variables at onset were statistically associated with any of the outcome variables measured. Fifty of the patients were compared to matched siblings and were found to have achieved comparable educations and salaries, and proportionate numbers of marriages and children.

Effects of extracellular calcium on low frequency induced potentiation and habituation in the in vitro hippocampal slice preparation

The electrophysiological characteristics of frequency potentiation and habituation were investigated in two afferent systems of the in vitro hippocampal slice preparation. Low frequency stimulation (1 Hz) of the Schaffer collateral - commissural (Sch-comm) fibers results in a short-term potentiation of the amplitude and rate of rise of the EPSP and population spike responses recorded in the CA1 region. In contrast, 1-Hz stimulation of the perforant path (PP) evokes a short-term, habituation-like depression of the dentate granule cell EPSP and population spike. An inverse relationship was observed between stimulus intensity and the magnitude of frequency potentiation or habituation. Changes in afferent fiber volleys or general excitability of postsynaptic membranes did not contribute significantly to the development of either of these forms of short-term plasticity. Perfusion with a medium containing a high calcium - low magnesium concentration (4 mM Ca+2 and 1 mM Mg+2) produced a differential effect on CA1 and dentate evoked potentials. Following a 20-min exposure to this medium, the amplitude of CA1 potentials was increased while dentate responses were decreased. Frequency potentiation of CA1 responses and habituation of dentate responses were depressed or eliminated by the high calcium medium. The opposing influence of extracellular calcium on CA1 and dentate evoked potentials indicates a fundamental difference in the process of transmitter release in these systems, a characteristic that may contribute to the production of frequency potentiation and habituation.

Pirprofen (Rengasil) in the treatment of juvenile rheumatoid arthritis. A segment I study

Thirty-two patients with JRA were enrolled in a 4-wk open-labeled, non-controlled multicentre trial of pirprofen. An initial dose of about 300 mg/m2/d (range 250-330) was gradually increased to a maximum of 600 mg/m2/d (range 413-761). The medication was provided as an aqueous suspension (10 mg/ml), and was given 4 times/d. Efficacy analysis showed significant decreases occurred in the DMS, travel time, grip strength, and the severity of swelling score (in all cases p less than 0.05 based on the paired Student t test, 2-tailed). Nineteen patients reported a total of 27 adverse experiences; 6 of which were attributable to pirprofen. At the study dosages used pirprofen seems to be very similar in efficacy and safety to other nonsteroidal antiinflammatory drugs investigated in children with JRA.

Functional tests of the corpus callosum in schizophrenia

The corpus callosum, a cerebral commissure of 200,000,000 fibres, is thickened in chronic schizophrenia and several neuropsychological and neurophysiological techniques have suggested poor links between the two cerebral hemispheres. The interhemispheric conduction time across the corpus callosum, measured in 12 schizophrenics, using the ipsilateral/contralateral latency differences of the early somatosensory evoked response, was found to be effectively zero. It is suggested that schizophrenia is a split-brain condition akin to agenesis of the corpus callosum, unrecognized through the use of compensatory ipsilateral sensory pathways.

Commissural potentiation of perforant path evoked responses in the dentate gyrus of the rat

The effects of conditioning stimuli applied to the commissural pathway on the perforant path (PP) evoked EPSP and population spike response were examined in urethane anaesthetized rats. Whereas conditioning stimuli applied to the PP resulted in a short-term potentiation of both the EPSP and population spike evoked by a test pulse to the same pathway (homosynaptic potentiation), only the population spike was potential when the PP test pulse was preceded by a conditioning volley to the commissural afferent. This form of heterosynaptic potentiation, which occurs in the absence of any significant change in the synaptic currents generated by the perforant path, suggests that alterations in postsynaptic excitability may underly the process of short-term potentiation rather than an augmented transmitter release.

Calcium uptake and retention during long-term potentiation of neuronal activity in the rat hippocampal slice preparation

Alterations in 45Ca uptake and retention as well as total intracellular calcium content were measured in hippocampal 'in vitro' slice preparations following the induction of long-term potentiation (LTP) in CA1 pyramidal neurones. The results indicate that tetanic stimulation of the Schaffer-commissural input produces a significant increase in the uptake and retention of calcium which parallels LTP of the CA1 population spike response.

In vitro responses of lymphocytes in juvenile arthritis: effects of time and concentration of PHA-P

The effects of concentration of PHA-P and time in culture on cells from patients with systemic, polyarticular and pauciarticular juvenile arthritis have been studied. Responses to suboptimal concentrations are depressed at 3 days, particularly of systemic and polyarticular patients, but normal by 5 days and probably prolonged at 7 days. The responses approach normal with 5 micrograms/ml PHA-P. This delay also occurs in cells from children with cystic fibrosis and acute pneumonia and so is not disease specific. Kinetic studies show a slower recruitment of cells. The delay is corrected by 1 microgram/ml indomethacin. After 7 days, cultures from patients with juvenile arthritis have fewer E, heat-stable E, and EAC rosetting cells than do cultures from normal children or children with cystic fibrosis.

[3H]2-Deoxy-D-glucose capture in the hippocampus and dentate gyrus of ketamine-anesthetized rat

Glucose capture in the hippocampus and dentate gyrus was studied after administration of [3H]2-deoxy-D-glucose in ketamine-anesthetized rats, using film and fine-grain emulsion autoradiography. On films, the densest label distribution occurred over the distal one-third of CA1 apical dendrites in both the dorsal and ventral hippocampus. The molecular layer of the dentate gyrus was also heavily labeled. On fine-grain emulsions, grain counts in the neuropil of these regions were significantly higher than over CA1 pyramidal cells or dentate granule cell bodies. It is suggested that the greatest label accumulation in the hippocampus occurs in perisynaptic sites in stratum lacunosum-moleculare of CA1.

Clq binding in serum in juvenile rheumatoid arthritis

The Clq assay for antigen-antibody complexes was performed on 79 blood samples from 43 patients with juvenile rheumatoid arthritis (JRA). The results were compared with assays for the activation products of C3 (C3c,d), for the concentration of C3, for rheumatoid factor, and for antinuclear antibodies. A statistically significant association was found between Clq binding and positive tests for latex fixation and C3c,d in systemic and polyarticular JRA, but positive results of each assay were found independently. These 3 assays were usually negative in pauciarticular JRA. No relationship was found between Clq binding and C3 concentration or antinuclear antibodies.

Component concentrations and activation of the complement system in neonatal illness: a preliminary study of necrotizing enterocolitis

Determinations of C3, C4, and C5 concentrations by radial immunodiffusion, and assays for the activation products of C3, C3c and C3d by counterimmunoelectrophoresis, were performed on 80 infants. Seven nonbacteremic preterm infants with necrotizing enterocolitis (NEC) or probable NEC (PNEC) were found at the time of diagnosis to have a significantly lower mean concentration of C3 (P less than 0.05, 1-tailed) without C3 activation when compared to other noninfected preterm infants. Ten full-term and 63 preterm infants were studied prospectively during the first days of life, and were then followed for the postnatal development of localized or systemic infection. Assays for the detection of C3 activation products were negative in all these infants. Four preterm infants who developed PNEC after 5 or more days without clinical illness had low original concentrations of complement components. The pathogenesis of NEC may not involve primarily complement activation, and susceptibility to this condition may be related to pre-existing deficiencies in complement component concentrations relative to gestational age, or to defective activation of C3 in the presence of certain bacterial species and strains.

Comparison of three assays for anti-DNA with three assays for the measurement of the role of complement in systemic lupus erythematosus in adolescents

Three assays for anti-DNA antibody were compared simultaneously with assays for Clq binding, C3 concentration, and the activation of C3 (C3c,d) on blood of children with systemic lupus erythematosus. The Farr assay and the Millipore filter assay for anti-DNA were abnormal most frequently, followed by the assay for C3c,d. Positive assays for C3c,d were closely associated with abnormal Millipore filter assays. Clq binding was elevated in 42% of samples, but was not associated with any other abnormality. The hemagglutination assay for anti-DNA and the C3 concentrations were the least frequently abnormal.

Nephropathy in the Wiskott-Aldrich syndrome

Nephropathy was detected in five of 32 patients with the Wiskott-Aldrich syndrome who were participating in a study of transfer factor (TF) therapy. In two patients, nephropathy was present before TF and did not appear changed by TF therapy. One of these patients subsequently developed progressive renal failure requiring dialysis beginning 5 1/2 years after TF therapy. In two patients, decreased renal function appeared very soon after the administration of TF. One patient showed gradually decreasing renal function beginning after two years of TF therapy. An additional patient was identified who died with renal failure without having received TF. The results suggest that renal failure occurs in the Wiskott-Aldrich syndrome more frequently than generally recognized and that administration of TF may precipitate or accelerate the renal disease in patients with this syndrome.

Influence of S-adenosylmethionine on DAPI-induced fluorescence of polyphosphate in the yeast vacuole

Use of the fluorochrome 4',6-diamidino-2-phenylindole.2 HCl (DAPI) in ultraviolet microscopy revealed fluorescent objects in Brownian motion within the vacuoles of seven species of yeast. The abundance of these bodies increased when cells of Saccharomyces cerevisiae were transferred from growth medium to a glucose-phosphate solution, indicating that they contain polyphosphate. In addition, the effect on vacuolar fluorescence of supplementing a defined growth medium with amino acids provided evidence that they also contained S-adenosylmethionine. These deductions were supported by in vitro studies of the interaction and fluorescence of polyphosphate, S-adenosylmethionine, and DAPI. Vacuolar fluorescence of cells in suspension in flucose-phosphate solution was less after addition of exogenous arginine, lysine, or glutamine but not after addition of alanine, aspartic acid, or methionine. Mithramycin was superior to DAPI as a fluorochrome for ultraviolet demonstration of yeast nuclei since it stained the nuclei much more intensely and did not fluoresce with other material in the cells.

Induction of normal ascosporogenesis in two-spored Saccharomyces cerevisiae by glucose, acetate, and zinc

In an apomictic strain of Saccharomyces cerevisiae that normally produces two-spored asci, production of three and four-spored asci was restored by adjusting zinc and carbon source levels in presporulation and sporulation media. Sporogenic capability was compared after growth in defined and undefined presporulation environments. Cultivation in defined presporulation medium containing 6% glucose followed by sporulation in 3.5% acetate yielded 16 +/- 3% three- and four-spored asci. Inclusion of 25 mug of zinc sulfate per ml in presporulation medium or 25 mug of zinc acetate per ml in sporulation medium gave a further increase in yield of three- and four-spored asci; it reached 48 +/- 1% when zinc was added to both media. Cells grown in undefined presporulation medium were incapable of three- and four-spored ascus development in acetate sporulation medium unless zinc was included in the latter medium. Cultivation in defined presporulation medium amended with yeast extract, peptone, or casein hydrolysate greatly reduced three- and four-spored ascus yields. Inclusion of a meiotic inhibitor (glucose) in sporulation medium inhibited three- and four-spored ascus production but not two-spored ascus production. Nuclear staining demonstrated two classes of asci: binucleate (one and two spored) and tetranucleate (three and four spored). Hence, some control over apomictic versus normal ascus development has been gained by nutritional manipulation.

Prolonged use of large intravenous steroid pulses in the rheumatic diseases of children

Nineteen children with rheumatic diseases refractory to standard treatment were given repeated large "pulses" of corticosteroid therapy. The pulses consisted of four repeated doses of 500 mg of hydrocortisone given intravenously over 20 to 30 minutes at six-hour intervals or of single intravenous injections of 30 mg/kg of methylprednisolone. All patients had temporary relief of signs or symptoms of inflammation. Complications were mild and only one child was removed from therapy because of a complication. Two children were judged to be treatment failures. Five patients have been weaned from all steroid treatment, and eight have required continued pulses at one- or two-week intervals as outpatients to maintain control. All of these have been able to reduce oral prednisone doses. Effects of the two forms of pulse appear similar. However, two children responded to the series of injections of hydrocortisone but not to single doses of methylprednisolone. Pulses have been given for periods up to three years without evident toxicity. Further work to define doses, schedules, and optimal drug is needed since this approach to steroid use appears effective and relatively nontoxic.

Pharmacological identification of acetylcholine and glutamate excitatory systems in the dentate gyrus of the rat

The responses of dentate granule cells to medial septum (MS) and perforant path (PP) stimulation were examined in urethane anaesthetized rats. MS and PP stimulation evoked an orthodromic activation of granule cells which was correlated with the negative transient of the characteristic field potential elicited from each site. The effects of electrophoretic application of acetylcholine (ACh) and glutamate (Glu) were examined on granule cells identified in this manner. The excitatory action of ACh but not that of Glu was antagonized by atropine. Glutamate diethylester (GDEE) blocked the excitation produced by Glu but not ACh. The synaptically evoked excitation elicited by MS was blocked by atropine but unaltered by GDEE whereas the PP excitatory response was blocked by GDEE and unaltered by atropine. The results of this study indicate that two discrete excitatory systems are present in the dentate gyrus of the rat: a cholinergic system originating in the medial septum and a glutamate mediated system originating in the entorhinal cortex.

Effects of simple imidazoles on human peripheral blood lymphocytes stimulated by mitogen or allogeneic cells

Five imidazole compounds were added to cultures of human lymphocytes which had been stimulated to undergo blast transformation by exposure to phytohaemagglutinin, pokeweed mitogen or allogeneic cells. Two compounds, clotrimazole and dacarbazine (DTIC) produced a dose related suppression of these responses. Nimorazole was largely inactive whereas metronidazole and tinidazole actually enhanced the response--at least in those cultures stimulated by the plant mitogens. It is suggested that experiments of this kind are helpful in identifying those imidazole compounds that could be used as immunosuppressants in vivo.

Inhibition of the mixed lymphocyte reaction by fractionated niridazole urine dialysate

Urine dialysate from rats treated orally with 25 mg/Kg 3H-labeled niridazole was fractionated by DEAE-Sepharose column chromatography and was found to contain three radioactive metabolites and no parent compound. When human niridazole urine dialysate (NUD) was fractionated under identical conditions, fractions corresponding to the three rat NUD metabolites were found to inhibit the human one-way MLR. No inhibition was obtained with fractionated control urine dialysate. It was concluded that nonimmunosuppressive niridazole is metabolized by rats and man to produce three active compounds with the ability to suppress the in vitro response to alloantigens.

Differences in in vitro incorporation of tritiated deoxycytidine and tritiated thymidine into human lymphocytes

Human lymphocytes stimulated in vitro by PHA or PWM incorporate 3H-CdR into DNA, but less well than 3H-TdR. More 3H-CdR is incorporated in populations enriched for T cells. No 3H-CdR is used by cells stimulated by lipopolysaccharides under circumstances in which 3H-TdR is incorporated. We conclude that human T cells and B cells differ in their ability to use 3H-CdR.

Differences in utilization of tritiated thymidine and tritiated deoxycytidine by rat lymph node cells

Large lymphoid cells and plasma cells in antigenically stimulated rat lymph nodes retain less label after injection of 3H-CdR than after injection of 3H-TdR. There is no difference amongst small lymphocytes. The data are consistent with a defect in the utilization of 3H-CdR in the late stages of B cell maturation in the rat.

The immunologic and clinical associations of the split products of C3 in plasma in juvenile rheumatoid arthritis

A qualitative counterimmunoelectrophoretic assay for the complement activation products C3c and C3d was used to study plasma from children with juvenile rheumatoid arthritis (JRA) and other rheumatic diseases. Positive tests for C3c,d were found in all patients with active systemic lupus erythematosus (SLE), 7 of 10 patients with active systemic JRA, 16 of 29 with active polyarticular JRA, 7 of 20 with active pauciarticular JRA, and in only 2 of 20 with inactive joint disease. The incidence of positive assays for C3c,d in JRA was increased in the presence of positive latex fixation tests, antinuclear antibody tests, or elevated values for antiglobulins as determined by affinity chromatography, but these associations were not statistically significant. Three joint fluids from children with pauciarticular JRA were negative for C3c,d. These studies show that the subgroups of JRA defined by clinical criteria are heterogeneous by current laboratory parameters and that evidence implicating antigen-antibody complexes in the pathogenesis of JRA is lacking in many patients.

Sporulation in single-spore isolates from amitrole-induced multispored asci of Saccharomyces cerevisiae

Amitrole treatment causes multispored ascus production by cells of a yeast strain whose asci normally contain two diploid spores. Single spores were isolated from asci containing two to eight spores and their ability to germinate was determined. Cells in colonies grown from single spores sporulated in the same manner as the parent strain indicating that amitrole had not induced meiotic division in the developing asci.

Calcium-dependent increase in spike duration during repetitive firing of Aplysia axon in the presence of TEA

Repetitive stimulation was studied in the axon of the giant neuron, R2, of Aplysia in the presence of TEA. In 25 or 50 mM extracellular TEA, a plateau develops on the axon spike during repetitive stimulation at frequencies greater than 3/sec. The plateau in extracellular TEA is inhibited by 30 mM CoCl2 or 1 mM CdCl2, and is enhanced by raising the Ca concentration. Intracellular TEA induces a plateau on the axon spike at frequencies less than 1/30sec. This plateau increases in duration with repetitive stimulation at higher frequencies and is inhibited by 30 mM CoCl2 or 1 mM CdCl2. The increase in spike duration during repetitive firing in the presence of TEA is indicative of an increased entry of Ca during the spike train.

Behcet's disease presenting as chronic aphthous stomatitis in a child

Behcet's disease is a chronic, recurrent, inflammatory disease of unknown cause that involves mucous surfaces, skin, eyes, joints, and the CNS. Although not reported in the pediatric literature, some cases start in childhood. This report describes a child whose chronic oral and genital ulcers preceded recognition of her gastrointestinal tract, eye, and CNS disease for nine years. The current knowledge of Behcet's disease in children is discussed.

Free proline content and sensitivity to desiccation and heat during yeast sporulation and spore germination

Ascospores of a strain of Saccharomyces cerevisiae Hansen were less sensitive to desiccation and heat than vegetative cells. Desiccation resistance was acquired earlier during sporulation and lost later during spore germination than heat resistance. As spores matured, resistance to both stresses increased. With the exception of the first few hours in sporulation medium, when proline appeared to be utilized, the intracellular free proline content increased during sporulation and decreased during spore germination. Not all the proline lost could be detected in the germination medium, indicating that some was metabolically utilized by the germinating spores. Since exogenous proline supplied to vegetative or sporulating cells before desiccation increased their survival, it is suggested that the high level of free proline in mature spores may protect against desiccation stress.

A trial of lactose hydrolysed milk in Australian Aboriginal children

Weight gains in 50 young Australian Aboriginal children were studied in a blind controlled hospital trial of reconstituted, lactose hydrolysed milk powder (test) and full-cream milk powder (control). The mean weight gains (+/- SEM) were 4.80 +/- 0.80 g kg-1 day-1 for children receiving the lactose hydrolysed milk, and 2.20 +/- 0.75 g kg-1 day-1 for those receiving the normal milk P less than 0.0125). Weight gain of infants (that is, those under one year of age) in the control group was less than 10% of that in the test group (P less than 0.0025). Weight gain was higher in children fed hydrolysed milk irrespective of percentage of Standard Weight for Age or the presence or absence of recognizable symptoms of lactose intolerance. Lactose malabsorption appears to be a major factor in the growth retardation of Aboriginal children. It is recommended that lactose hydrolysed milk replace normal milk in the supplementary feeding of Aboriginal infants and children.

Immunosuppressive properties of sera and urine dialysates from kidney-graft recipients treated with azathioprine, prednisolone, and niridazole

Niridazole, an antischistosomal agent, was given to renal transplant recipients in addition to azathioprine and prednisolone, as there is experimental evidence that this combination of drugs is highly immunosuppressive. Sera obtained from kidney-graft recipients during the first two weeks after transplantation were examined for their ability to inhibit the one-way mixed lymphocyte reaction (MLR). Sera from seven patients receiving azathioprine, prednisolone, and niridazole (triple-drug treatment), five patients receiving azathioprine and prednisolone, and two other patients treated with niridazole alone for schistosomiasis produced MLR inhibition by comparison with pretreatment (control) sera.A mean of 78% inhibition was observed with sera taken after one day's treatment with the three-drug combination, whereas this level of in-vitro immunosuppression occurred only after eight days of treatment with azathioprine and prednisolone. Niridazole alone produced an effect similar to azathioprine and prednisolone. Concentrated dialysate of urine from a patient receiving triple-drug treatment not only inhibited the MLR but also significantly prolonged the survival of heterotopic heart allografts in rats, whereas dialysate from the same patient after niridazole had been stopped gave less MLR inhibition and failed to prolong heart allograft survival.Since niridazole thus increased the in-vitro and in-vivo immunosuppressive action of azathioprine and prednisolone, we suggest that this triple-drug combination might be useful for preventing early acute kidney graft rejection.