Auditory sensory gating, hippocampal volume, and catecholamine metabolism in schizophrenics and their siblings

Schizophrenia may result from the concerted action of several pathophysiological factors. This pilot study compared the distribution of measurements of three such putative factors in 11 schizophrenics and their siblings: a neurophysiological deficit in auditory sensory gating, diminished hippocampal volume, and increased catecholamine metabolism. Abnormal auditory sensory gating was found in all schizophrenics in the 11 families studied and in 8 of their 20 siblings. Compared with the schizophrenics, the clinically unaffected siblings with abnormal auditory gating had larger hippocampal volume. There was no similar difference for the siblings with normal gating. The siblings with abnormal auditory gating also had lower homovanillic acid levels than the other siblings. The data suggest that a familial neuronal deficit, identified by diminished sensory gating, may be a necessary, but not sufficient factor in the pathogenesis of schizophrenia. Individuals with this deficit are generally clinically unaffected, except for schizophrenics, who also have other abnormalities, such as diminished hippocampal volume and increased catecholamine metabolism.

The effects of drug therapy on radiographic progression of rheumatoid arthritis. Results of a 36-week randomized trial comparing methotrexate and auranofin

OBJECTIVE

To determine the effects of drug therapy (methotrexate [MTX] versus auranofin [AUR]) on radiographic progression in patients with active rheumatoid arthritis (RA).

METHODS

We conducted a 9-month randomized, multicenter, double-blind trial comparing MTX and AUR. Standardized radiographs of the hands and wrists were obtained at baseline and at completion of the study. Four experienced bone radiologists graded the radiographs for erosions, joint space narrowing, erosion healing, and reparative bone formation.

RESULTS

Two hundred eighty-one patients were enrolled in the study. Radiographs were available on 167 of the 183 who completed the trial. After 9 months of therapy, there was a significantly greater worsening of the erosion score in the AUR group (mean +/- SEM change of 1.67 +/- 0.4) compared with the change in the MTX group (0.60 +/- 0.3) (P = 0.040). There was also a significantly greater worsening of the joint space narrowing score in the AUR group compared with the MTX group (1.36 +/- 0.3 versus 0.42 +/- 0.2) (P = 0.007). There was no difference demonstrated between groups in healing of erosions or in reparative bone formation.

CONCLUSION

The rate of radiographic progression in patients with RA, as measured by erosion score and joint space narrowing score, was demonstrated to be lower in those treated with MTX, as compared with AUR, over a 36-week period.

Auditory sensory gating and catecholamine metabolism in schizophrenic and normal subjects

Diminished neuronal response to repeated sensory input is a sensory-gating phenomenon that has been found to be deficient in schizophrenic patients. For example, schizophrenic patients fail to decrease the amplitude of the P50 wave of the auditory evoked potential to the second of paired click stimuli. In some studies, however, normal subjects have also failed to decrease their P50 responses. The aim of this study was to determine if accommodation to the recording situation over time would affect the gating of the P50 response. The gating of the P50 wave is measured as the ratio of the amplitude of the second response to the amplitude of the first. Three successive auditory evoked potentials were compiled, each from trains of 32 pairs of stimuli. Twelve normal subjects and 12 schizophrenic patients were studied. Unconjugated catecholamine metabolites were measured from venous samples drawn before and after the electrophysiological recording. Between the first and third trials, the normal subjects significantly increased their gating of P50. This increase in gating of P50 was related to decreased levels of the noradrenergic metabolite 3-methoxy-4-hydroxyphenylglycol. No similar phenomenon was observed in the schizophrenic patients, a number of whom had a further decrease in P50 gating over the three trials. Transient failure to observe gating of P50 in normal subjects may be related to increased state-dependent noradrenergic activity, which is known to disrupt sensory gating. This mechanism does not seem to account for the more persistent failure of sensory gating in schizophrenia.

Musculoskeletal manifestations in beta 2-microglobulin amyloidosis. Case discussion

The cases presented illustrate some of the typical (case 1) and less common (case 2) clinical features of beta 2m amyloidosis. The accumulation of beta 2m amyloid in tissues is a potentially severe complication of dialysis-treated chronic renal failure. Beta 2m amyloidosis has been shown to have distinct clinical, radiologic, and pathologic features. The pathogenesis of this condition is not yet clearly understood, and recommendations for the clinical management of these patients at present are limited to recognition of the disease and symptomatic treatment. Further insights into the biology of this disease should lead to new strategies for prevention and treatment.

Anorexic contribution to increased linoleate mobilization and oxidation in lymphoma-bearing mice

To test for a regulatory defect in adipose triacylglycerol (essential) fatty acid mobilization in lymphoma-bearing mice, free [1-14C]linoleic acid/mouse serum albumin was injected iv into lymphoma-bearing and control mice, adapted to a reversed light cycle, and studied in three dietary states in the dark period. Mean daily food intake decreased in mice with small and large tumor burdens. Plasma free fatty acid (FFA) oxidation rates, which approximate FFA mobilization rates, were estimated by multicompartmental analysis (CONSAM). Oxidation of linoleate to CO2 was reduced significantly (85%) in ad libitum fed as compared to briefly fasted control mice but not in fed vs. fasted mice with large or small tumor burdens. However, plasma FFA oxidation rates to CO2 did not differ in briefly fasted tumor-bearing and pair-fed control mice. When re-fed a 250-mg test meal, briefly fasted mice with small tumors suppressed plasma free linoleic acid oxidation, as did controls. During simulated night, mildly anorexic, tumor-bearing mice with small tumor burdens mobilized essential fatty acids much faster than controls. This could explain body fat loss. The abnormally rapid rates of FFA (free linoleic acid) mobilization at night probably result from anorexia rather than from inability of food to suppress fat mobilization.

Effect of human mammary MX-1 tumor on plasma free fatty acids in fasted and fasted-refed nude mice

We hypothesized that tumor-bearing (TB) nude mice, because they are reported to have no detectable, circulating tumor necrosis factor (TNF)/cachectin, would regulate their plasma free fatty acid (FFA) levels normally when fasted and refed. We compared levels of individual plasma FFA in response to fasting (24 hr) and to refeeding (for 20 hr after fasting) a fat-free, 65% sucrose diet in control, nude mice and in mice bearing 1.3 +/- 0.4 g MX-1 tumors. Total plasma FFA levels were typically high in 24-hr fasted mice [mean concentrations in microM +/- SE (n); controls 515 +/- 63 (6); TB, 625 +/- 63 (6)]. FFA levels were reduced by 65% in each group in response to refeeding. Each major plasma FFA species fell in response to refeeding, except arachidonate, which did not change significantly (fasted vs. fasted-refed concentrations) in either controls or TB mice. In refed mice, the molar FFA ratio of oleate to linoleate rose; however, that of oleate to arachidonate fell markedly. TB nude mice had normal appetites. We conclude that all species of FFA were mobilized from adipose tissue in a normal manner in TB nude mice; therefore, regulation of adipose triacylglycerol fatty acid mobilization (as plasma FFA) by dietary sugar is probably not affected by MX-1 tumor growth in these mice. Our findings are consistent with the hypothesis that nude mice may be unable to secrete TNF/cachectin in response to tumor growth, but they do not establish whether or not endogenous, circulating TNF/cachectin increases FFA mobilization in any TB animal.

Renal epithelium: reversal of cytotoxic damage by addition of anti-thymocyte globulin

A novel in vitro assay of renal epithelium tight junction function was used to assess the efficacy with which rabbit anti-thymocyte globulin (ATG) blocks epithelium damage mediated by lymphokine-activated killer (LAK) cells. It was found that LAK cells lysed renal epithelial cells poorly in standard chromium-release assays but that they caused a rapid, and almost total, reduction in trans-epithelium monolayer resistance, indicating tight junction failure and, hence, loss of tissue function. LAK cell-mediated cytolysis of the sensitive K562 cell line was completely blocked in the presence of ATG at a concentration of 200 micrograms/ml. Addition of ATG at this concentration to damaged renal cell monolayers in the presence of LAK cells allowed the trans-monolayer resistance to recover rapidly to levels approaching the values recorded before initial addition of LAK cells. On this basis it seems likely that the rapid restoration of renal function frequently observed after appropriate "rescue" therapy during episodes of acute rejection may reflect subtle changes in tissue function rather than recovery from widespread graft cell cytolysis.

Evidence of extensive phospholipid fatty acid methylation during the assumed selective methylation of plasma free fatty acids by diazomethane

We compared a conventional method (Method I) for measuring plasma free fatty acid (FFA) concentrations with two more rapid procedures (Method II and Method III). Method I required total lipid extraction, separation of FFA by thin-layer chromatography, methylation, and gas-liquid chromatographic analysis of the fatty acid (FA) methyl esters. Method II was a colorimetric procedure. Method III relied upon diazomethane's presumed ability to selectively methylate FFA even in the presence of FA esters. The three methods were compared using plasma from fasted and from fed nude mice, tumor-bearing mice (MX-1 and ZR-75-1 human mammary carcinomas), and controls. Method II, was less reliable than Method I, but both gave similar mean values for plasma FFA levels in fasted mice. Both Methods I and II also showed similar lowering of plasma FFA levels after feeding previously fasted mice. Method III consistently gave values that were far greater than those obtained using Methods I and II. Moreover, highly significant differences between fasted and fed mice were obscured by direct methylation of plasma FFA with diazomethane (Method III). The excess FA methyl esters formed in Method III were derived from plasma phospholipids, but not from plasma triacylglycerols. After feeding fasted mice, plasma free palmitic acid and oleic acid levels fell (Method I); by contrast, the excess "FFA" formed by methylation of plasma phospholipid FA increased two-fold and fourteen-fold, respectively. Caution is therefore advised in the use of direct methylating agents when measuring total and individual plasma FFA levels.

Model development to describe the heterogeneous kinetics of apolipoprotein B and triglyceride in hypertriglyceridemic subjects

The heterogeneous nature of very low density lipoprotein (VLDL) metabolism in hypertriglyceridemia gives rise to complex kinetics when labeled VLDL are traced. Analysis of such systems benefits from the simultaneous study of several metabolically discrete subfractions which are then integrated. We have studied the kinetics of VLDL and intermediate density lipoprotein (IDL) apoprotein B and triglyceride simultaneously by injecting homologous 125I-labeled VLDL1 and 131I-labeled VLDL2 and [2-3H]glycerol intravenously in three diverse type IV hyperlipoproteinemic subjects. An additional type IV subject received only [2-3H]glycerol. Specific radioactivities were measured in: VLDL1-triglyceride and -apoB, VLDL2-triglyceride and -apoB, and in each corresponding subfraction after further separation into heparin-Sepharose-bound and -unbound fractions. ApoB and triglyceride specific radioactivities were also measured in IDL. Analysis of the kinetics of apoB in the unbound fractions in VLDL1 and VLDL2 showed the presence of two pools of particles, one of which turned over rapidly. The kinetics of apoB in the bound fractions in VLDL1 and VLDL2 were, in contrast, dominated by a large slowly turning over pool of particles that resembled the kinetics of whole VLDL. Evidence of a partial precursor-product relationship between the unbound and bound fractions suggested that the former was richer in nascent-like particles, while the latter contained more remnant particles. However, triglyceride specific radioactivity curves for both unbound and bound fractions showed initial rapid rises and broad peaks, indicating that the bound fraction also contained a substantial proportion of nascent-like particles. Using multicompartmental analysis, a model was constructed to account for the kinetics of both apoB and triglyceride in all fractions of VLDL and in IDL. The model comprises two parallel delipidation pathways that supply a common remnant pool with these features: 1) multiple direct inputs of particles into plasma at VLDL2 and IDL levels; 2) heterogeneous triglyceride precursor pools leading to different rates of labeling of VLDL1 and VLDL2; 3) very substantial delipidation of VLDL2 particles prior to conversion to IDL and; 5) triglyceride production rates somewhat higher than previously reported. The inclusion in the model of the rapidly turning over pool of triglyceride-rich particles, identified in the heparin-unbound fraction, suggests that values for triglyceride production in man have been underestimated.

Effect of oral antacid administration on the pharmacokinetics of oral fluconazole

Absorption and elimination of fluconazole after oral administration of a 100-mg capsule were unaffected by concomitant administration of an antacid containing aluminum and magnesium hydroxides.

The influence of properties encoded by the Yersinia virulence plasmid on adhesion of Yersinia enterocolitica to ileal brush border membrane vesicles

The influence of plasmid-associated cell surface structures on the ability of Yersinia enterocolitica to bind to ileal brush border membrane vesicles (BBVs) was investigated. Rabbit or human BBVs were immobilized on polystyrene microtiter plates and adhesion of radiolabeled cells of Y. enterocolitica was determined. Strains of pathogenic serotypes carrying the Yersinia virulence plasmid (pYV+), as well as their isogenic plasmid cured derivatives (pYV-), adhered to immobilized BBVs, but adhesion of pYV+ organisms was markedly greater than that of pYV- ones. Strains belonging to non-pathogenic serotypes did not adhere significantly. The pYV+ strain Ye0301P+ did not express specific adhesion to glycolipids, nor was adhesion to BBVs reduced in the presence of various monosaccharides. Proteolytic digestion of surface structures on strain Ye0301P+ markedly reduced adhesion. pYV+ strains also demonstrated greater adhesion to a non-biological surface (polystyrene) and showed a higher degree of hydrophobicity than pYV- organisms as evaluated in a two-phase partitioning system. It is therefore likely that the plasmid-associated adhesion of Y. enterocolitica is promoted by one or more outer membrane proteins, that confer hydrophobicity to the bacterial surface.

Glycosphingolipid receptors for Pseudomonas aeruginosa

The binding of Pseudomonas aeruginosa to glycosphingolipids and to buccal and bronchial epithelial cells was analyzed. Three independently expressed specificities were found by bacterial binding to glycosphingolipids separated by thin-layer chromatography. All strains bound gangliotria- and gangliotetrasylceramide. All but one of the strains bound sialic acid-containing glycosphingolipids and lactosylceramide. The latter two specificities could be separated in that the lactosylceramide binding was retained and the sialic acid binding was suppressed when bovine serum albumin was used as a blocking agent in the thin-layer chromatography assay. The attachment to buccal epithelial cells, like the binding to sialylated compounds and lactosylceramide, was abolished by Formalin treatment of the bacteria, suggesting the importance of these specificities for cell adherence. In contrast, the binding to gangliotria- and gangliotetraosylceramide was retained by nonattaching Formalin-treated bacteria.

Reduced suppression of plasma saturated fatty acid mobilization and oxidation by feeding in lymphoma-bearing mice

Lymphoma-bearing mice have a circulating lipid-mobilizing factor, but increased plasma free fatty acid (FFA) turnover has not been demonstrable in earlier studies using postabsorptive tumor-bearing mice. We hypothesized that FFA mobilization in lymphoma-bearing mice is only elevated in fed mice and may best be observed at night (dark, reversed light cycle). AKR mice with early and advanced tumors (10(6) SL-3 lymphoma cells, i.p.) and controls were fed ad libitum (reversed light cycle, dark) or fasted 4 h (daylight, regular cycle), given injections of [14C]bicarbonate of [1-14C]palmitate-mouse serum albumin, i.v., and plasma [14C]FFA disappearance and/or breath 14CO2 were monitored. Plasma FFA mobilization, estimated by multicompartmental analysis (SAAM) of the oxidation rate was lower in fasted mice with advanced tumors [tumor, 9.5 +/- 6.0% (%SE); controls, 14 +/- 4.4% micrograms-atoms fatty acid-carbon/min/30 g body weight, n = 3 to 6 mice/time point/group]. Feeding reduced these rates 90% in control mice and 53% in mice with early tumors, but only 14% in mice with advanced tumors. Plasma FFA fractional catabolic rates were 2.5 times faster in fed mice with advanced tumors than in controls. Diminished suppression of fatty acid mobilization in fed tumor-bearing mice (at night) probably accounts partially for the body fat loss.

Lack of relationship of auditory gating defects to negative symptoms in schizophrenia

The differences between schizophrenic patients with positive and negative symptoms have been the subject of extensive investigations. Psychophysiologists have proposed that there are elementary auditory sensory processing deficits in schizophrenia, but their prevalence in particular positive or negative subtypes has not been described. Our previous studies have shown that schizophrenics have impaired auditory sensory gating relative to normal controls, as demonstrated by the P50 auditory evoked potential conditioning-testing paradigm. In this paradigm, schizophrenics fail to show the normally expected diminished response to the second or 'test' stimulus. In the present study we assessed the possible relationship of this defect to negative symptoms in 20 schizophrenic patients treated with neuroleptics. Nine patients met the Andreasen criteria for predominantly 'negative schizophrenia'. 12 normal controls with no family history of schizophrenia were also studied electrophysiologically. Negative schizophrenics showed greater impairment than patients without such symptoms on the Trails B test of organic impairment, but there were no differences between groups on electrophysiological measurements of auditory sensory gating. Both schizophrenic groups showed impaired P50 auditory gating compared to normal controls. Both groups of schizophrenics also had a significantly diminished amplitude of the N100 waveform in the conditioning response, compared to normal controls. Auditory sensory processing defects in schizophrenia appear to be independent of negative symptoms.

Sensory physiology and catecholamines in schizophrenia and mania

Hypersensitivity to sensory stimulation is a prominent characteristic of both schizophrenia and mania. Neurophysiological recordings suggest a common deficit in a central neuronal sensory gating mechanism which regulates sensitivity to repeated auditory stimuli. Dopamine and norepinephrine are hypothesized to have major roles in these illnesses, but their role in aberrant sensory processing has not yet been proved. Presumptive evidence for effects of catecholamines on sensory processing comes from psychophysiological studies of normal subjects challenged with stimulants who show decreased sensory gating, and studies of psychotic patients treated with neuroleptics who show improved function. Studies of similar phenomena in animals show comparable effects of catecholamines on sensory processing, both behaviorally and at the single neuron level. In this study, gating of auditory evoked potentials (EPs) during treatment of both illnesses was compared with plasma dopamine and norepinephrine metabolites. Comparisons of medicated and unmedicated states showed that schizophrenic patients have a fixed deficit in sensory gating, which is a familial trait, unchanged by medication. During acute illness, they have an additional transient hypersensitivity to stimuli, manifested as smaller EPs, which seems to be mediated by dopamine. Manic patients have only the deficit in sensory gating, which is transient and seems to be mediated by norepinephrine. Thus, similar neurophysiological deficits in the two psychoses are associated with different biochemical abnormalities, which may explain similarities in acute symptoms and differences in other aspects of the illnesses, such as their response to treatment.

Turnover and fate of plasma free fatty acids in briefly-fasted lymphoma-bearing mice

Body fat loss during tumor growth may be due to increased mobilization of adipose triglycerides. Earlier work from this laboratory suggested that (i) lymphoma-bearing AKR mice have a circulating lipid mobilizing factor (LMF) which caused body fat loss during cancer growth; that (ii) fatty acids (FA) mobilized in these tumor-bearing (TB) mice were not oxidized to CO2 as in starved mice that lose their body fat; and that (iii) instead, the mobilized FA were sequestered by the lymphoma. We tested these hypotheses by injecting [1-14C]palmitate-albumin into lymphoma-bearing and control mice. We measured turnover of plasma FFA for 24 hr and predicted the cumulative conversion of tracer into breath 14CO2 (at 85 min) in the TB mice. Plasma FFA were mobilized more slowly in briefly fasted tumor-bearing mice than in controls with the same plasma FFA pool sizes. The fractional catabolic rate (FCR) (min-1) of plasma FFA turnover in both groups decreased during the night when the mice ate: postabsorptive controls, 1.07 (+/- 5.6%); fed controls, 0.25 (+/- 13%); postabsorptive TB, 0.53 (+/- 4.6%); fed TB, 0.29 (+/- 7.3%). Virtually all of the plasma FFA irreversible disposal in TB mice was accounted for as breath 14CO2 (30 to 40% I.D.), not as tumor lipids (1.1 +/- 0.22% I.D.). Thus, FFA oxidation to CO2 is the major fate of plasma FFA turnover in TB mice, and sequestration of FFA (palmitate) by tumor cells is a quantitatively minor process. The putative circulating LMF did not cause increased FFA mobilization in these lymphoma-bearing mice in the post-absorptive state.

Binding specificities of wild-type and cloned Escherichia coli strains that recognize globo-A

In this study we compared the specificity for the globoseries of glycolipids of Escherichia coli expressing the O-negative, A-positive (ONAP) adhesin and clones transformed with the pap-like (prs or pap-2) gene cluster. Receptor-active glycolipids were identified by the ability of radiolabeled bacteria to bind to the glycolipids on thin-layer chromatogram plates. The ONAP adhesin and pap-like clones bound with high affinity to the globo-A and Forssman glycolipids. The ONAP strains did not recognize other glycolipids of the globoseries. In contrast, the pap-like clones also showed weak binding to globotriaosylceramide and reacted weakly with Gal alpha 1----4 Gal beta-latex beads. We suggest that the pap-like and ONAP adhesins recognize an epitope shared by the globo-A and Forssman structures, e.g., terminal GalNAc alpha 1----3 bound to Gal alpha 1----4Gal beta-containing glycolipids.

Increased platelet intracellular calcium concentration in patients with bipolar affective disorders

Using the fluorescent indicator Fura 2, we measured the free intracellular calcium ion concentration in blood platelets of patients with untreated mania, bipolar depression, and unipolar depression; patients who had recovered from bipolar depression or mania; and age- and sex-matched controls. The baseline intracellular calcium ion concentration was significantly increased in platelets from patients with mania compared with controls. The free intracellular calcium ion concentration after stimulation with platelet-activating factor and thrombin was significantly higher in platelets of manic and bipolar depressed patients than in all other groups. The degree to which intracellular calcium ion concentration increased over baseline after stimulation was significantly lower in unipolar than in bipolar patients. These findings suggest that platelets of manic and depressed bipolar patients have a similar enhancement of intracellular calcium ion activity that is distinctly different from the decreased ability of platelets of unipolar patients to mobilize intracellular calcium in response to stimulation.

Globo-A--a new receptor specificity for attaching Escherichia coli

Uropathogenic Escherichia coli strains designated as ONAP, based on their O negative A positive agglutination of human P1 erythrocytes, were shown to prefer the globo-A glycolipid as a receptor structure. The dependence on both the A terminal and the globoseries chain was confirmed by agglutination of human AP1, but not Ap or OP1 erythrocytes and by binding to the globo-A glycolipid on TLC plates. Neither Gal alpha 1----4Gal beta nor the A trisaccharide GalNAc alpha 1----3(Fuc alpha 1----2)Gal beta alone functioned as receptors. The bacteria thus appeared to recognize an epitope resulting from the combination of the terminal and internal structures.

Fat pad triacylglycerol fatty acid loss and oxidation as indices of total body triacylglycerol fatty acid mobilization and oxidation in starving mice

We tested our hypothesis that, kinetically, triacylglycerol fatty acids in heterogeneously labeled adipocytes behave similarly to the whole fat pad triacylglycerol fatty acid during starvation in mice. Adipose triacylglycerol fatty acids were labeled with [1-14C]palmitate (complexed to albumin) by injection of a small bolus (2-5 microliter) into either epididymal or inguinal fat pads. Both 14C-labeled triacylglycerol fatty acid spec. act. and breath 14CO2 spec. act. were monitored 30 min after tracer injection and after 24-72 h starvation. Adipose triacylglycerol fatty acid spec. act. remained approximately constant during fasting, i.e., tracer and mass disappeared at similar rates. Negligible translocation of labeled triacylglycerol fatty acid from the injection site to other parts of the same fat pad or to distant fat pads occurred. Triacylglycerol fatty acid was mobilized more slowly from epididymal than from inguinal fat pads in two of three studies. Triacylglycerol fatty acid disappearance (loss) from inguinal fat pads was more replicable than from epididymal fat pads and more closely reflected the fall in whole body total lipid during starvation. The estimated percent of breath CO2-carbon derived from adipose triacylglycerol fatty acid increased from an average of approx. 32% in the postabsorptive state to about 77% after 48 h starvation. The data help to validate the direct tracer injection technique as a means of studying adipose triacylglycerol fatty acid turnover and oxidation. This approach should be particularly useful for studying the fate of adipose triacylglycerol fatty acid when it is mobilized. e.g., during states of inanition and starvation and in response to hormones and cancer-induced cachexia.

Cerebral coenurosis in a cat

Coenurus serialis, the intermediate stage of Taenia serialis, was the cause of progressive, fatal, intracranial disease in a 5-year-old cat. X-Ray computed tomographic findings were identical to those associated with intracranial parasitic cysts in people, in whom x-ray computed tomographic features are considered pathognomonic and superior to those of other diagnostic methods. The presumed source of the coenurus was the owner's dog.