Metabolic effects of adding sucrose and aspartame to the diet of subjects with noninsulin-dependent diabetes mellitus

This study compared the effects of adding sucrose and aspartame to the usual diet of individuals with well-controlled noninsulin-dependent diabetes mellitus (NIDDM). A double-blind, cross-over design was used with each 6-wk study period. During the sucrose period, 45 g sucrose (9% of total daily energy) was added, 10 g with each main meal and 5 g with each between-meal beverage. An equivalent sweetening quantity of aspartame (162 mg) was ingested during the aspartame period. The addition of sucrose did not have a deleterious effect on glycemic control, lipids, glucose tolerance, or insulin action. No differences were observed between sucrose and aspartame. Sucrose added as an integral part of the diabetic diet does not adversely affect metabolic control in well-controlled NIDDM subjects. Aspartame is an acceptable sugar substitute for diabetic individuals but no specific advantage over sucrose was demonstrated.

Impact of juvenile arthritis on families. An educational assessment

State of the art patient education programs have as their goals changes in behaviors, coping styles, health status, and/or costs. The accomplishment of these goals often involves not only the patient but also his or her whole family. This is especially true if the patient is a child. Based on this premise, we undertook an educational needs assessment of 50 children with juvenile arthritis (JA) and their families. Through utilization of a grounded theory methodology, open-ended questionnaires were completed by JA children, their parents, and their siblings. The resulting analysis suggests (1) the need for family-based education, (2) differing needs of various family members, and (3) several hypotheses for further study.

Breath hydrogen excretion in infants with colic

Breath hydrogen excretion as an index of incomplete lactose absorption was measured in 118 healthy infants who were either breast fed or given a formula feed containing lactose, some of whom had colic. Infants with colic (n = 65) were selected on the basis of the mother's report of a history of inconsolable crying lasting several hours each day. Infants in the control group (n = 53) were not reported to cry excessively by their mothers. Breath samples were collected using a face mask sampling device preprandially, and 90 and 150 minutes after the start of a feed. Normalised breath hydrogen concentrations were higher in the group with colic than in the control group at each time point. The median maximum breath hydrogen concentration in the colic group was 29 ppm, and in the control group 11 ppm. The percentage of infants with incomplete lactose absorption (breath hydrogen concentration more than 20 ppm) in the colic group was 62% compared with 32% in the control group. The clinical importance of the observed association between increased breath hydrogen excretion and infantile colic remains to be determined. Increased breath hydrogen excretion indicative of incomplete lactose absorption may be either a cause or an effect of colic in infants.

Photoaffinity labeling of dopamine D1 receptors

A high-affinity radioiodinated D1 receptor photoaffinity probe, (+/-)-7-[125I]iodo-8-hydroxy-3-methyl-1-(4-azidophenyl)-2,3,4,5-tetra hyd ro- 1H-3-benzazepine ([125I]IMAB), has been synthesized and characterized. In the absence of light, [125I]IMAB bound in a saturable and reversible manner to sites in canine brain striatal membranes with high affinity (KD approximately equal to 220 pM). The binding of [125I]IMAB was stereoselectively and competitively inhibited by dopaminergic agonists and antagonists with an appropriate pharmacological specificity for D1 receptors. The ligand binding subunit of the dopamine D1 receptor was visualized by autoradiography following photoaffinity labeling with [125I]IMAB and sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Upon photolysis, [125I]IMAB incorporated into a protein of apparent agents in a stereoselective manner with a potency order typical of dopamine D1 receptors. In addition, smaller subunits of apparent Mr 62,000 and 51,000 were also specifically labeled by [125I]IMAB in these species. Photoaffinity labeling in the absence or presence of multiple protease inhibitors did not alter the migration pattern of [125I]IMAB-labeled subunits upon denaturing electrophoresis in both the absence or presence of urea or thiol reducing/oxidizing reagents. [125I]IMAB should prove to be a useful tool for the subsequent molecular characterization of the D1 receptor from various sources and under differing pathophysiological states.

Kinetics of the formation of thrombin-thrombospondin complexes: involvement of a 77-kDa intermediate

Thrombin forms sodium dodecyl sulfate stable complexes of 77 and greater than 450 kDa with proteins secreted by activated platelets. The kinetics of formation of these complexes were investigated by addition of 125I-thrombin to the supernatant solution of A23187-activated platelets. Complexes were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis either with or without reduction of disulfide bonds. When analyzed on nonreduced gels, the 77-kDa complex reached a maximum at about 3 min and then declined as the greater than 450-kDa complex increased. On reduced gels (on which there was no greater than 450-kDa complex) the 77-kDa complex approached the level of the greater than 450-kDa complex on nonreduced gels. The half-time of formation was less than 1 min for the 77-kDa complex and about 15 min for the greater than 450-kDa complex. These time courses suggested that the 77-kDa complex was incorporated into the greater than 450-kDa complex as an essential precursor. Formation of complexes was inhibited by a competitive inhibitor or a noncompetitive inhibitor of thrombin, and the pH dependence of formation of both complexes was similar to the pH dependence for catalytic activity of thrombin. Ca2+ inhibited formation of the greater than 450-kDa complex but not of the 77-kDa complex. A model is presented in which thrombin and a secreted protein form a 77-kDa complex by a process that involves the active site of thrombin. The 77-kDa complex is then incorporated into a greater than 450-kDa complex by thiol-disulfide exchange with thrombospondin, a process that is inhibited by Ca2+. Thrombin in the greater than 450-kDa complex had no catalytic activity.

Conversion of angiotensin I to angiotensin II by cathepsin A isoenzymes of porcine kidney

We have reported the existence of a carboxypeptidase in a human renal extract that converts Angiotensin I (AI) to Angiotensin II (AII) in two steps with des-leu-AI (dl-AI) being formed as an intermediate. Since this carboxypeptidase had properties similar to cathepsin A, the ability of cathepsin A to metabolize AI was studied. Cathepsin A was purified from hog kidney with enzyme activity being monitored using both benzyloxycarbonyl-glutamyl-tyrosine (ZGT) and AI as substrates. The procedure separated the expected large and small molecular weight forms of cathepsin A as well as two additional isoenzymes. All of the isoenzymes had carboxypeptidase activity with ZGT, AI, and dl-AI. No detectable cleavage of AII was observed. Cathepsin A,S (small) activity with ZGT or AI as substrate was inhibited to a similar extent by diisopropylfluorophosphate, mersalyl acid, and a decapeptide renin inhibitor. It is concluded that the renal angiotensin carboxypeptidase activity is catalyzed by cathepsin A. By its ability to convert AI to AII, cathepsin A may be a component of the intrarenal renin-angiotensin system.

Dual role of norepinephrine in the hippocampal CA1 region of the rat: inhibition and disinhibition

Norepinephrine (NE) has been shown to produce either an inhibitory or an excitatory influence on CA1 pyramidal neurons of the hippocampus depending on the dosage. It was suggested that NE, in addition to exerting a direct inhibitory effect on pyramidal cells, may also act upon recurrent inhibitory interneurons to produce a disinhibition of the pyramidal cells. The present study was undertaken to examine the effect of NE on alveus-evoked inhibition, presumably mediated by the basket cell interneurons innervating the pyramidal cells. Experiments were carried out on the in vitro hippocampal slice preparation and inhibition was assessed by the percent reduction of the stratum radiatum evoked population spike response when preceded by a conditioning pulse delivered to the alveus to activate the inhibitory interneurons via the recurrent collaterals of the pyramidal cells. Paired pulse stimulation resulted in inhibition of the stratum radiatum evoked test response with conditioning-test intervals up to 60 ms. NE (50 microM) perfusion resulted in a significant and reversible reduction of the alveus-evoked recurrent inhibition. Intracellular recordings using a similar paired pulse paradigm corroborated the extracellular data well. The possible roles of NE in the physiological functioning and pathophysiology of epileptiform activity of the hippocampus are discussed.

Insulin-like growth factors I and II in children with systemic onset juvenile arthritis

Systemic onset juvenile arthritis (JA) has been associated with growth failure in children whether or not treated with adrenocorticosteroids. Growth hormone secretion has been reported to be normal, but production of insulin-like growth factors has not been studied. We measured serum concentrations of insulin-like growth factor I and II in a group of children with systemic JA at different times, and during treatment with only nonsteroidal antiinflammatory therapy or while receiving prednisone. Mean concentrations of insulin-like growth factor I and II were below normal for age whether or not prednisone was being given. Growth failure during periods of active disease was observed in both groups. Only 4 of 11 prepubertal children in whom growth rates were measured grew 4.5 cm or more/year. However, longitudinal studies of individual children showed that lowest growth rates occurred while taking prednisone and that growth rates were not correlated to insulin-like growth factor levels.

Des-Leu angiotensin I: biosynthesis and drinking response

The crude rat and bovine synaptosomal lysate from brain can hydrolyze angiotensin I (AI) to des-Leu angiotensin I (AI-dL) and no further. This cytosolic enzyme has a specificity for angiotensin-related sequences, R-His-Pro-Phe-His-Leu and therefore named angiotensin-related carboxypeptidase (ARC). These studies led to the biosynthesis and purification of AI-dL in order to determine if it can provoke a drinking response. This nonapeptide is a potent dipsogen when injected into the cerebroventricles of rats. The drinking response probably requires a second hydrolysis to angiotensin II (AII) since both captopril and saralasin can inhibit this response.

Complexes of thrombin with secreted platelet proteins

A labeled 77-kDa complex formed when 125I-thrombin was added to platelet suspensions or to the supernatant solution of ionophore-activated platelets. Prostacyclin inhibited complex formation with whole platelets but not with the supernatant solution of ionophore-activated platelets. This is evidence that the complex formed with a factor secreted from activated platelets. Smaller complexes of 70 and 58 kDa formed between labeled thrombin and lysed platelets. The 77-kDa complex was necessary for the formation of a thrombin-thrombospondin complex.

Subcellular localization in rat brain of angiotensin-related carboxypeptidase activity distinct from converting enzyme

Whole brain synaptosomes contain both an isorenin activity and angiotensin-related carboxypeptidase activity. Further hydrolysis of des-Leu angiotensin I (AI-dL) occurs more slowly; hydrolysis of angiotensin II (AII) is negligible. Vasopressin and oxytocin but not vasotocin can inhibit angiotensin-related carboxypeptidase activity. Since AII has been shown to induce vasopressin secretion, this correlation suggests a feedback inhibition by vasopressin of this enzymatic cascade. Commercially available radioimmunoassays for AI and AII show a 3.4 and 6.0% crossreactivity, respectively. When the absolute concentration of AI-dL exceeded 500 ng/ml, both antibodies to AI and AII showed maximal displacement of radiolabel. This suggests that these antibodies may not distinguish between AI-dL from other peptides during immunocytochemistry.

Action-potential discharge in hippocampal CA1 pyramidal neurons: current source-density analysis

1. The site of origin of evoked action-potential discharge in hippocampal CA1 pyramidal neurons was investigated using the in vitro rat hippocampal slice preparation. 2. Action-potential discharge in pyramidal cells was evoked by stimulation of efferent pyramidal cell fibers in the alveus (antidromic) or afferent synaptic inputs in stratum oriens (SO) or stratum radiatum (SR). Laminar profiles of evoked extracellular field potentials were recorded at 25-micron intervals along the entire dendrosomatic axis of the pyramidal cell and a one-dimensional current source-density analysis was applied. 3. Suprathreshold stimulation of the alveus evoked an antidromic population spike response and current sink with the shortest peak latency in stratum pyramidale or proximal stratum oriens. A biphasic positive/negative potential associated with a current source/sink was recorded in dendritic regions, with both components increasing in peak latency with distance from the border of stratum pyramidale. 4. Suprathreshold stimulation of SO or SR evoked a population spike response superimposed upon the underlying synaptic depolarization at all levels of the dendrosomatic axis. The shortest latency population spike and current sink were recorded in stratum pyramidale or proximal stratum oriens. In dendritic regions, a biphasic positive/negative potential and current source/sink conducted with increasing latency from the border of stratum pyramidale. 5. A direct comparison of alvear- and SR-evoked responses revealed a basic similarity in population spike potentials and associated sink/source relationships at both the somatic and dendritic level and a similar shift in peak latency of spike components along the pyramidal cell axis. 6. It is concluded that the initial site for generation of a spike along the dendrosomatic axis of the pyramidal cell following antidromic or orthodromic stimulation is in the region of the cell body layer (soma or axon hillock). Action-potential discharge in dendritic regions then occurs as the result of a subsequent retrograde spike invasion of basal and apical dendritic arborizations.

Long-term increases in dentate granule cell responsivity accompany operant conditioning

The efficacy of synaptic transmission from the perforant path (PP) to the granule cells in the dentate gyrus (DG) of freely moving rats was monitored electrophysiologically over the course of training in an appetitively motivated, discriminated operant paradigm. Every day, 22 hr after behavioral sessions, evoked potentials were recorded from the DG following stimulation of the PP over range of current intensities and the amplitudes of the population spikes were measured. Behavioral conditions involved training in an operant conditioning paradigm or a session of free-feeding. Significant increases in population spike amplitudes were observed over the 8 d of training, but not over the 8 d of free-feeding. This training-induced increase in granule cell responsivity persisted for at least 10 d following the cessation of behavioral trials and was in many ways comparable to long-term potentiation (LTP), subsequently observed in these same rats 24 hr after tetanic stimulation. These data confirm and extend previous reports of synaptic enhancements following conditioning and suggest that such increases in synaptic efficacy may encode some aspect of learning.

Interleukin-2 production by lymphocytes from blood of children with arthritis is less suppressed than in systemic lupus or cystic fibrosis

Interleukin-2 (IL-2) production by cells from children with various forms of arthritis, systemic lupus erythematosus, and cystic fibrosis was compared. In all cases more IL-2 was detectable at 24 than at 48 h and production was increased by addition of indomethacin. Cultures from children with either active lupus or the pneumonia of cystic fibrosis produced very little IL-2, but cultures from children with arthritis produced apparently normal amounts. We conclude that depressed production of IL-2 in juvenile arthritis may be a secondary epiphenomenon and not a primary immunologic deficit.

Psychosocial risk and resistance factors among children with chronic illness, healthy siblings, and healthy controls

Psychosocial risk and resistance factors within the domains of parental functioning, family stressors, and family resources were examined as predictors of psychological adjustment and physical problems in juvenile rheumatic disease patients (N = 93), their healthy siblings (N = 72), and demographically matched healthy controls (N = 93). Family socioeconomic status and background variables showed few consistent relationships with child functioning. However, a constellation of risk and resistance factors tended to show comparable associations with functioning for patients, siblings, and controls. Higher parental depression and medical symptoms and more family stressors, sibling problems, and burden of illness on the family predicted more problems among the patients. These relationships held when disease duration and severity were controlled. For the siblings, increased parental and patient dysfunction, more family stressors, and less family cohesion and expressiveness were associated with more problems. Although the associations were not as strong, mothers' depression and lack of family cohesion and expressiveness also were related to more adjustment problems among the control children. These findings imply that there may be a general association between certain risk and resistance factors and childhood adaptation.

Spontaneous secretion of a proteoglycan releasing factor by mononuclear cells in juvenile arthritis

Patients with juvenile arthritis (JA) spontaneously produced a substance which accelerated proteoglycan loss from cultured articular cartilage. Peripheral blood mononuclear cells (PBMC) from 15 patients with JA were cultured for varying days, and cell-free PBMC conditioned media were added to articular cartilage cultures. Release of proteoglycan and collagen from cartilage was quantified by analysis of chondroitin sulfate and hydroxyproline content, respectively, after 4 days of culture. Conditioned media from PBMC of patients with systemic onset JA (3/3) and 5/7 patients with polyarticular JA increased release of proteoglycan when added to cartilage cultures. Mitogen stimulation of the PBMC was unnecessary for activity and addition of mitogen did not alter proteoglycan release. The PBMC conditioned media from the other patients (2/7) with polyarticular JA, from patients (3/3) with systemic onset JA which had progressed to polyarticular JA, and from patients with pauciarticular JA, did not enhance proteoglycan release without mitogen stimulation. PBMC of normal children produced media which enhanced proteoglycan release after mitogen stimulation. No conditioned medium accelerated proteoglycan release if cartilage was freeze killed before culture and none tested reduced cartilage collagen content.

Cell division age dependency of meiosis in an apomictic variant of Saccharomyces cerevisiae

The cell division age dependency of sporulation was investigated in a diploid strain of Saccharomyces cerevisiae (19el) which undergoes a single equational nuclear division during sporulation with consequent formation of asci containing two uninucleate diploid spores (apomictic dyads). Under modified nutritional conditions which partially restore meiosis and hence normal tetrad formation, newly formed (age 0) daughter cells were observed to be capable of formation of apomictic dyads but not of meiotic tetrads. Even under conditions in which only apomictic dyads developed, approximately 20% of the asci resulted from differentiation of newborn 'inexperienced' cells. Thus, the data indicated production of at least one bud to be a prerequisite for meiosis but not for apomixis; however, occurrence of at least one complete mitotic cell division cycle was evidently insufficient for the morphogenetic switch from diploid to haploid spore formation, since older cells bearing several bud scars often underwent apomictic dyad development, and some produced no spores.

Distribution of Calbindin-D28K 1 (CaBP) in the cerebral cortex and hippocampus of the epileptic (El) mouse

The distribution of Calbindin-D28K (CaBP), a calcium-binding protein that binds Ca2+ with high affinity, was measured by radioimmunoassay in various cortical regions of the epileptic strain of mice El. The El strain, in which seizures are induced by repeated vestibular stimulation, had significantly lower levels of CaBP in the hippocampus and dorsal occipital cortical areas than the control CF-1 strain. Following induction of seizures in the El strain, a further decrease in CaBP levels was observed in the hippocampal formation and ventral temporal cortical regions, areas where paroxysmal activity is generated in this strain. Considering the role of CaBP as an intraneuronal calcium buffer, the present findings indicate that neuronal calcium regulation is genetically altered in the El strain and is further disturbed during the events that lead to induction of seizures.

Psychosocial adaptation in juvenile rheumatic disease: A controlled evaluation

Juvenile rheumatic diseases are serious chronic illnesses potentially capable of disrupting a child's development and functioning. This study examined the psychosocial functioning of 43 children with severe rheumatic disease as compared to that of 52 children with a milder or inactive form of rheumatic disease. Both patient groups also were compared to 93 healthy children from demographically matched families. Data were obtained from parent reports, from physician evaluation, and, for children who were old enough, from self-reports. The severe patient group showed more parent-reported psychological and physical problems than both the mild patient group and the healthy controls. Compared to the mild group, the severe group also missed more days of school due to illness. Older children in the severe group were more likely to miss school due to illness and to participate in fewer social activities with their families and friends than the controls; however, the older children reported comparable mood and functioning in other areas. An expanded model is proposed to examine risk and resistance factors predictive of psychological and social dysfunction among children with severe chronic disease.

Different patterns of C3 and C4 activation in the varied types of juvenile arthritis

Quantitative assays for C3 and C4 activation were carried out simultaneously on blood from children with varied types of juvenile arthritis. Factor VIII-related antigen was also measured as an indicator of vascular damage. In active systemic juvenile arthritis, the C4d/C4 ratio was frequently elevated and was usually associated with elevated C3d/C3 ratios and elevated concentrations of factor VIII-related antigen. Children with chronic polyarticular arthritis, no matter which forms of onset they had had, also had increased levels of the C4d/C4 ratio, C3d/C3 ratio, and factor VIII-related antigen, but these were less consistent and were not associated with each other. In contrast, in pauciarticular arthritis there was a uniquely isolated increase in the C3d/C3 ratio. This work implies that there are different mechanisms responsible for complement activation in the different types and at different stages of juvenile arthritis.