Hepatic stimulator substance is a liver growth stimulator derived from the hepatocyte cytosol of weanling or regenerating adult rat livers. The present paper reports the almost 9,000-fold purification of hepatic stimulator substance with an approximately 100,000-fold increase in specific growth stimulator activity. Purification steps included heating at 95 degrees C for 15 min, 40% cold ethanol precipitation, passage over Procion Red HE3B, DEAE cellulose and Sephadex G75 columns and gel filtration and reverse-phase fast protein liquid chromatography techniques. As little as 27 ng per ml of the purest material produced a 2-fold stimulation in the standard HTC cell activity assay. Further studies indicate that hepatic stimulator substance is a highly negatively charged protein and that disulfide bonds or a complex tertiary structure are not essential to its activity. Hepatic stimulator substance is stable over a wide range of pH's and temperatures. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis with silver stain revealed 1 major band at 12,400 daltons and 1 minor band at 17,500 daltons.

Animals↗

PubMedDate not supplied

Circadian rhythmicity of ACTH and corticosterone in the rat.

The circadian secretion of ACTH and corticosterone was assessed by measuring immunoreactive ACTH concentration in the plasma and ACTH content in the anterior and posterior pituitary over a 30 h period in groups of both male and female rats and comparing these data to fluorometric corticosterone concentration in the plasma and corticosterone content in the adrenal. A circadian rhythm of plasma corticosterone levels and adrenal content was apparent in both males and females with the highest levels at the onset of darkness. In contrast, there was no significant circadian rhythm in plasma ACTH levels or anterior or posterior ACTH pituitary content. Because the ACTH and corticosterone rhythms were dissociated, rhythmic corticosterone secretion is not entirely dependent on ACTH secretion.

Adrenal Glands↗

PubMedDate not supplied

Comparison of two assays (EIA and EITB) and two samples (saliva and serum) for the diagnosis of neurocysticercosis.

The enzyme immunoassay (EIA), standardized with a crude extract, and the enzyme-linked immunoelectrotransfer blot assay (ETIB) with glycoprotein antigens, were compared by using saliva and serum in the search for specific antibodies against Taenia solium larvae, for the diagnosis of neurocysticercosis. Saliva was slightly more sensitive in EIA (82.1%) than serum (74.1%). In EITB serum was far more sensitive (100%) than saliva (70.4%). The use of EITB with serum is thus an excellent choice for diagnosis of clinical cases of neurocysticercosis, while EIA using saliva represents a useful combination for diagnosis and, especially, epidemiology, because saliva is easily obtained by a painless and non-invasive procedure and the technique is simpler to perform. Furthermore, cross-reactivity of EIA with Echinococcus does not interfere in countries like Mexico where human hydatid disease is not present.

Animals↗

PubMedDate not supplied

Immunoblot (western blot) and double diffusion (DD5) tests for hydatid disease cross-react with sera from patients with cysticercosis.

Explore the source record for details and available documents.

Adult↗

PubMedDate not supplied

Epidemiological investigation of Taenia solium taeniasis and cysticercosis in a rural village of Michoacan state, Mexico.

We performed a survey for taeniasis and cysticercosis among persons living in a Mexican village where Taenia solium infection in pigs was known to be enzootic. A standardized questionnaire was administered in all 577 households to obtain medical histories and information on demographic and environmental factors and on risk factors associated with transmission of infection. Serum and/or stool specimens were obtained from 1005 volunteers and examined for cysticercosis antibodies and intestinal parasites. Faecal examination of 828 participants revealed infection by Taenia sp. in 2 (0.2%). Three additional cases of taeniasis were detected in individuals who evacuated proglottids after treatment with praziquantel. Of 1005 human serum specimens, 49 (4.9%) were positive in the cysticercosis immunoblot assay. Seropositivity increased with age and reached a peak in subjects aged 46-55 years (P < 0.05). A history of seizures was significantly associated with seropositivity (P < 0.05); approximately 25% of persons with such histories were seropositive. Histories of headache, dizziness, trembling, blurred vision, and vomiting were also significantly associated with positive immunoblot assays. This study has demonstrated previously undiagnosed morbidity associated with T. solium neurocysticercosis and identified community behavioural and environmental practices that must be modified to prevent continued transmission of cysticercosis and taeniasis.

Adolescent↗

PubMedDate not supplied

Application of a Rasch analysis to the examination of the perception of facial affect among persons with mental retardation.

An instrument for the assessment of perception of nonverbal facial affect was developed and administered to two separate groups of respondents: adults with mental retardation and adults without mental retardation. The instrument was developed and calibrated using an item response theory (Rasch) analysis on respondents without mental retardation. Following assurance of item stability, data were analyzed using an anchored analysis for persons without mental retardation. Cumulative score differences between the two groups were expected and were found. The Rasch analysis uncovered a difference in the structure of the latent trait of understanding of facial affect between the two groups. In view of these qualitative differences, the argument is presented that quantitative differences in the two groups are irrelevant. We suggest that qualitative differences such as those found herein may partially account for the traditionally limited scope of generalization and maintenance of treatment effects of social skills training with persons with mental retardation. Theoretical and empirical implications of the findings, and future research directions based on these qualitative differences are discussed.

Activities of Daily Living↗

PubMedDate not supplied

Application of the Stages of Change Scale in a clinical drug trial.

The Stages of Change Scale (SOC: McConnaughy, Prochaska, & Velicer, 1983) was used to predict outcome among 131 outpatients with generalized anxiety disorder who were enrolled in a clinical drug trial. As predicted, subjects high on Precontemplation did not experience as much relief from anxiety as subjects low on Precontemplation, whereas subjects high on Contemplation or Action experienced more decrease in anxiety during the trial than subjects low on these stages. Contrary to our hypothesis, only Contemplation was related to illness severity changes, and scores on the Maintenance scale were not related to outcome. Of the four stage scores, only Maintenance was related to premature termination of treatment. There were no differences between drug (adinazolam) and placebo groups and only Action scores interacted with drug/placebo assignment in this study. Results suggest that the SOC may be useful in identifying individuals who are most likely to experience decreased anxiety while enrolled in a clinical drug trial.

Adult↗

PubMedDate not supplied

Neurotensin induces calcium oscillations in cultured amacrine cells.

The peptide, neurotensin, is found in a class of amacrine cells synapsing chiefly with other amacrine cells in the chicken retina (Li & Lam, 1990; Watt et al., 1991). To investigate the possible effects of neurotensin, we have used Ca2+ imaging to measure cytosolic Ca2+ concentrations in cultured chick amacrine cells. Following a delay of about 2 min, neurotensin (300 nM) induced oscillations in Ca2+ concentration that typically had a period of 2 min and peak values of about 300 nM when averaged over the cell body. The phospholipase C inhibitors U-73, 112 and 4'-bromophenacyl bromide terminated oscillations induced by neurotensin but the protein kinase inhibitors H7 and staurosporine did not inhibit oscillations, increasing their frequency instead. In the absence of external Ca2+, neurotensin induced only a single Ca2+ transient, much briefer than when external Ca2+ was present. Together these results suggest that neurotensin activates phospholipase C, thereby producing IP3 that triggers Ca2+ release from an internal store. Although this released Ca2+ contributes to periodic Ca2+ peaks, the majority of cytosolic Ca2+, even in the first peak, comes from Ca2+ influx across the plasmalemma.

Amino Acid Sequence↗

PubMedDate not supplied

Signal clipping by the rod output synapse.

The properties of synapses between retinal neurons make an essential contribution to early visual processing. Light produces a graded hyperpolarization in photoreceptors, up to 25 mV in amplitude, and it is conventionally assumed that all of this response range is available for coding visual information. We report here, however, that the rod output synapse rectifies strongly, so that only potential changes within 5 mV of the rod dark potential are transmitted effectively to postsynaptic horizontal cells. This finding is consistent with the voltage-dependence of the calcium current presumed to control neurotransmitter release from rods. It suggests functional roles for the strong electrical coupling of adjacent rods and the weak electrical coupling of adjacent rods and cones. The existence of photoreceptor coupling resolves the apparent paradox that rods have a 25 mV response range, while signals greater than 5 mV in amplitude are clipped during synaptic transmission. We predict that the strengths of rod-rod and rod-cone coupling are quantitatively linked to the relationship between the rod response range and the synapse operating range.

Animals↗