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C Greenbaum

Publications and source records attributed to C Greenbaum.

13 recordsLinked to original sources
PubMed2004

Conformation-dependent GAD65 autoantibodies in diabetes.

AIMS/HYPOTHESIS: Conformation-dependent autoantibodies directed against GAD65 are markers of Type 1 diabetes. In this study we aimed to determine whether the substitution of GAD65 with GAD67 amino acids would affect the binding of conformation-dependent GAD65 autoantibodies. METHODS: We used PCR-based site-directed mutagenesis to generate a series of mutated GAD65 cDNA constructs in which specific GAD65 coding sequences for regions of the protein critical for autoantibody binding were replaced with GAD67 coding sequences. RESULTS: The introduction of a point mutation at position 517, substituting glutamic acid with proline, markedly reduced the binding of disease-associated GAD65 antibodies. The binding of GAD65 antibodies to the E517P mutant was reduced in the sera of all newly diagnosed Type 1 diabetes patients ( n=85) by a mean of 72% ( p<0.0001) compared with binding to wild-type GAD65. Patients with latent autoimmune diabetes in adults ( n=24) showed a similar reduction in binding (79% reduction, p<0.0001). First-degree relatives who subsequently progressed to Type 1 diabetes ( n=12) showed a reduction in binding of 80% compared with a reduction of only 65% among relatives who had not progressed to disease ( n=38; p=0.025). In healthy GAD65Ab-positive individuals who did not progress to diabetes during a 9-year follow-up period ( n=51), binding to GAD65-E517P was reduced by only 28% compared with binding to wild-type GAD65. CONCLUSIONS/INTERPRETATION: Differences in autoantibody binding to wild-type GAD65 versus GAD65-E517P may provide predictive information about Type 1 diabetes risk beyond that provided by the presence or absence of GAD65 autoantibodies. Lack of binding to mutant GAD65-E517P defines GAD65-positive individuals who are at higher risk of developing diabetes.

Amino Acid Sequence↗
PubMed2001

Intermolecular antigen spreading occurs during the preclinical period of human type 1 diabetes.

Intra- and intermolecular spreading of T cell responses to autoantigens has been implicated in the pathogenesis of autoimmune diseases. Therefore, we questioned whether T cell responses from subjects identified as at-risk (positive for autoantibody reactivity to islet proteins) for the development of type 1 diabetes, a cell-mediated autoimmune disease, would demonstrate intermolecular Ag spreading of T cell responses to islet cell proteins. Previously, we have demonstrated that by the time subjects develop type 1 diabetes, they have T cell responses to numerous islet proteins, whereas T cells from normal controls respond to a limited number of islet proteins. Initial testing of PBMC responses from 25 nondiabetic at-risk subjects demonstrated that 16 of the 25 subjects have PBMC responses to islet proteins similar to controls. Fourteen of these 16 subjects were available for follow-up. Eleven of the 14 developed T cell responses to increasing numbers of islet proteins, and 6 of these subjects developed type 1 diabetes. In the nine subjects who already demonstrated T cell Ag spreading at the initial visit, four were available for follow-up. Of these four, two had increases in T cell reactivity to islet proteins, while two maintained their initial levels of T cell reactivity. We also observed Ag spreading in autoantibody reactivity to islet proteins in nine of the 18 at-risk subjects available for follow-up. Our data strongly support the conclusion that intermolecular spreading of T cell and Ab responses to islet proteins occurs during the preclinical period of type 1 diabetes.

Adolescent↗
PubMed2001

Accumulation of(125)iodine labeled interleukin-2 in the pancreas of NOD mice.

Interleukin-2 (IL-2) is an important cytokine in the autoimmune process proceeding Type 1 diabetes. Our aim was to investigate, in two previously used animal models, the NOD mouse and the BB/W rat, the in vivo tissue distribution of radio-labeled IL-2. If the radio-labeled IL-2 accumulated significantly in the pancreas compared to surrounding organs it could allow imaging of lymphocyte infiltration of the islets of Langerhans by scintigraphic methods. IL-2 was labeled enzymatically with(125)Iodine. Radio-labeled IL-2 was injected iv in prediabetic NOD mice, diabetic NOD mice and Balb/c mice in the first animal model and in BB rats in the second model. Animals were sacrificed at different time points and the activity in different organs was measured. It was found that the mean activity in the pancreas in both diabetic and prediabetic NOD mice was significantly higher compared to pancreas from Balb/c mice (P< 0.001 and P=0.005, respectively). However, the mean activity in the pancreas was at the lower range of the surrounding organs in both animal models, thereby excluding the possibility of imaging the autoimmune process by scintigraphic methods. It is concluded that radio-labeled IL-2 did accumulate significantly in the pancreas of NOD mice compared to control mice but there is a need to develop new techniques in order to visualize the localized activity.

Animals↗
PubMed2001

Developmental outcome of school-age children born to mothers with heroin dependency: importance of environmental factors.

Development of children aged 5 to 12 years born to mothers with heroin dependency raised at home or adopted was studied in comparison with: (1) children with environmental deprivation alone (i.e. low parental socioeconomic status [SES] and evidence of neglect), (2) children born to fathers with heroin dependency fathers, and (3) control individuals of average SES. One hundred and sixty children (84 males and 76 females; average age at examination 8 years) were evaluated between 1998 and 1999. All were attending mainstream schools. All participants were examined by a paediatrician and a psychologist using standard neurological and psychological age-appropriate tests, as well as tests and questionnaires to assess learning ability and attention span. The Conners and Achenbach questionnaires and the Pollack Taper test were used to assess possible presence of attention-deficit-hyperactivity disorder (ADHD). Mothers were assessed for ADHD using Wender's questionnaire. Children born to parents with heroin dependency raised at home and those of low SES exhibited intellectual impairment both on verbal and performance skills. They also had impaired reading and arithmetic skills. Children born to mothers with heroin dependency but who were adopted at a young age had normal intellectual and learning abilities, except for some reduced function on the performance Wechsler Intelligence Scale for Children-Revised. We found a high rate of ADHD among all children born to parents with heroin dependency, including those adopted, as well as in children with low parental SES. The highest rate of ADHD was in children born to mothers with heroin dependency raised at home, being twice that observed in the other groups. Mothers of these groups of children also had a high rate of ADHD.

Adult↗
PubMed2001

School-age children born to diabetic mothers and to mothers with gestational diabetes exhibit a high rate of inattention and fine and gross motor impairment.

OBJECTIVES: To study the neurobehavioral effects that pregestational and gestational diabetes might have on offspring at school age. STUDY DESIGN: We studied neurobehavioral function at school age of 57 children born to 48, well controlled, diabetic mothers and of 32 children born to 32 women with gestational diabetes. Their development was compared with 57 control children matched by age, birth order and parental socio-economic status, using a number of cognitive, behavioral, sensory and motor neurological tests. RESULTS: The IQ scores on the WISC-R and Bender tests of the children born to diabetic mothers were similar to those of control children, but the Bender scores of the children born to mothers with gestational diabetes were slightly lower. No differences were found between the study groups in various sensory-motor functions in comparison to controls. However, both study group children performed less well than controls in fine and gross motor functions as observed on the Bruininks-Oseretzki test of motor proficiency. The scores of children born to the mothers with pregestational diabetes were higher than controls on the Touwen & Prechtl neurological examination (worse function). The children from both research groups also performed worse on the Pollack taper test that is designed to detect inattention and hyperactivity. The children of the two study groups also had slightly higher scores on the Conners abbreviated parents-teachers questionnaire measuring hyperactivity and inattention, but the differences from controls were not statistically significant. We found a negative correlation between the performance of the children born to mothers with pregestational diabetes on various neurodevelopmental and behavioral tests and the severity of maternal hyperglycemia as assessed by blood glycosylated hemoglobin levels and acetonuria. CONCLUSIONS: Pregestational or gestational diabetes was found to adversely affect attention span and motor functions of offspring at school age, but not their cognitive ability. These effects were negatively correlated with the degree of maternal glycemic control, and were more pronounced in younger children.

Adult↗
PubMed2000

Comparison of the motor development of school-age children born to mothers with and without diabetes mellitus.

The objectives of this study were to examine the effects of diabetes during pregnancy on the long-term motor development of the offspring and to study possible correlations between glycemic control and motor development. We compared the motor development of 57 children, 5- to 12-years-of-age, born to 48 mothers with well-controlled diabetes, to the motor development of 57 control children matched by age, birth order, and parental socio-economic status. Children born to mothers with diabetes performed less well than controls in fine and gross motor functions on the Bruininks-Oseretsky Test of Motor Proficiency. A negative correlation existed between the test scores of the children whose mothers had diabetes and the severity of hyperglycemia as assessed by blood glycosylated hemoglobin levels and acetonuria. Motor ability of the children of mothers with diabetes had a high correlation with biological and environmental variables. These results suggest that diabetes during pregnancy may affect the developing brain, inducing long-term mild motor deficiency. The effects seem to result from the adverse effects of diabetic metabolic factors, and the effects correlate with the degree of diabetes control. The combination of metabolic functioning of women with diabetes and home environment may affect the motor development of their children.

Adolescent↗
PubMed1999

Neurodevelopmental outcome at early school age of children born to mothers with gestational diabetes.

AIMS: To study the metabolic derangements in the second half of pregnancy caused by gestational diabetes, on the long term development of children. METHODS: The neuropsychological function of 32 school age children born to 32 mothers with well controlled gestational diabetes and 57 control children matched by age, birth order, and parental socioeconomic status was studied. RESULTS: There were no differences in head circumference and height, but the children born to diabetic mothers were heavier. The verbal IQ scores of index children below the age of 9 years were lower than those of control children. No differences were found between the groups in various sensory and motor functions and in the Touwen and Prechtl neurological test. The young index group children performed less well than controls in fine and gross motor functions, as observed on the Bruininks-Oseretzky test of motor proficiency. The scores of young children born to mothers with gestational diabetes were also lower than controls on the Pollack tapper test, and there were more index group children who scored abnormally on the parents' Conners questionnaire. No correlation was found between the performance of the index group children on various neurodevelopmental tests and the severity of perinatal complications. The differences tended to disappear with age. CONCLUSIONS: Gestational diabetes, as a result of the metabolic abnormalities in the second half of pregnancy, induces long term minor neurological deficits which are more pronounced in younger children. There does not seem to be any direct relation between the appearance of congenital anomalies and neurodevelopmental outcome.

Child↗
PubMed1998

Neurobehaviour of school age children born to diabetic mothers.

AIM: To study the neurobehavioural effects that diabetes during pregnancy might have on children by school age. METHODS: The neurobehavioural function of 57 school age children born to 48, well controlled diabetic mothers was compared with 57 control children matched for age, birth order, and parental socioeconomic status, using several cognitive, behavioural, sensory and motor neurological tests. RESULTS: The IQ scores of the index group children were similar to those of control children (117.7 +/- 13.4 vs 118.5 +/- 10.1). There were no differences between the groups in various sensory motor functions. However, the index group children performed less well than the controls on indices of fine and gross motor functions, as observed on the Bruininks-Oseretzky test of motor proficiency. The scores of children born to diabetic mothers were higher than controls on the Touwen and Prechtl neurological examination. They also performed worse in the Pollack tapper test which is designed to detect minor neurological deficits, inattention, and hyperactivity. The index children had higher scores on the Conners abbreviated parent-teacher questionnaire which measures hyperactivity and inattention. There was a negative correlation between the performance of the index group children on various neurodevelopmental and behavioural tests and the severity of hyperglycaemia, as assessed by blood glycosylated haemoglobin and acetonuria. CONCLUSIONS: Diabetes during pregnancy adversely affects some fine neurological functions in children at school age, but not their cognitive scores. These effects are not correlated with the degree of glycaemic control.

Child↗
PubMed1996

Peripheral blood mononuclear cells of insulin-dependent diabetic patients respond to multiple islet cell proteins.

Insulin-dependent diabetes (IDDM) results from autoimmune destruction of pancreatic beta cells mediated predominantly by cellular effector mechanisms. To date, investigators have studied a limited number of islet cell proteins stimulatory to T cells. However, before development of clinical IDDM, the majority of the beta cells are impaired or destroyed. Thus, numerous proteins from lysed beta cells would be accessible to the immune system of the patient. Our goal was to investigate the PBMC reactivity of IDDM patients to the full spectrum of fractionated human pancreatic islet cell proteins to determine whether numerous islet cell proteins or a select few would be recognized. We observed that PBMCs from IDDM patients responded reproducibly (mean stimulation index, >2.0) to the proteins in all m.w. regions, whereas the mean stimulation index for controls from all m.w. regions was <2.0. Using three different islet protein preparations, PBMC responses of IDDM patients (n = 30) and controls (n = 39) to the islet cell proteins were significantly different. Dose responses were also demonstrated for the lymphocyte reactivity of the IDDM patients (n = 29) vs controls (n = 56) to the islet cell preparations. Proteins, presumably irrelevant to the IDDM disease process, from a human osteosarcoma cell line and normal human spleen cells did not stimulate PBMCs from IDDM patients or controls. Moreover, IDDM patients and controls responded similarly to mitogens and tetanus toxoid. These studies show that at the time of diagnosis of IDDM, PBMCs from IDDM patients are stimulated by a wide array of islet cell proteins.

Autoantigens↗
PubMed1996

Major histocompatibility complex class I molecule expression is normal on peripheral blood lymphocytes from patients with insulin-dependent diabetes mellitus.

Recent work from one laboratory has shown, in both nonobese diabetic mice and humans, an association between insulin-dependent diabetes mellitus (IDDM) and quantitative difference in MHC class I molecule expression. This reported decrease in MHC class I molecule expression is very controversial in the nonobese diabetic mouse model of IDDM, but to our knowledge, it has not been evaluated by another group in human IDDM. To evaluate this question, we studied 30 patients with IDDM and 30 age- and sex-matched normal controls. MHC class I molecule expression was measured by flow cytometry with conformational-dependent MHC class I mAbs. The mean antigen density of MHC class I molecule expression in IDDM vs. normal control is 454+/-34 vs. 440+/-28 for lymphocytes and 1,440+/-117 vs. 1,494+/- 117 for monocytes, both P > 0.05. Three conformational-dependent MHC class I antibodies showed consistent results. To estimate the biological variation of MHC class I molecule expression in normal controls, we also studied 10 age- and sex-matched normal control pairs. Using X +/-SD of the percentage difference of mean antigen density in the normal control pairs as our definition of normal, we found that 70% (21/30) of IDDM patients had normal, 13% (4/30) of IDDM patients had decreased, and 17% (5/30) of IDDM patients had increased MHC class I molecule expression on lymphocytes. All IDDM patients showed normal MHC class I expression on monocytes. In conclusion, we find that there is no consistent decrease in MHC class I molecule expression on either lymphocytes or monocytes from patients with IDDM. The MHC class I molecule expression observed in IDDM patients is largely within the expected biological variation of MHC class I molecule expression that has been observed in normal controls.

Adult↗
PubMedDate not supplied

Effects of an anti-CD5 immunoconjugate (CD5-plus) in recent onset type I diabetes mellitus: a preliminary investigation. The CD5 Diabetes Project Team.

Type-I (insulin-dependent) diabetes mellitus is an immunologically mediated disease that results in destruction of the insulin secreting beta cells of the pancreas. T cells have been implicated in the pathogenesis of this disease. One novel form of anti-T-cell therapy is the immunoconjugate CD5-Plus. This agent is composed of the murine IgG1 monoclonal antibody H65, which is directed toward the CD5+ antigen; and ricin A chain, a ribosomal inhibitor protein. We performed a pilot study to evaluate the safety of the immunoconjugate in subjects with type-I diabetes mellitus. We conducted a dose-escalation study using CD5-Plus given as an intravenous infusion for 5 consecutive days. Fifteen subjects (12 men and 3 women) with a mean age of 26 years, a mean duration of diabetes of 4.8 months, and a minimum stimulated C peptide of 0.3 pmol/mL were entered. Six subjects each were treated at the 0.1 and 0.2 mg/kg/day dosage levels, and three subjects were treated at the 0.33 mg/kg/day dose. Glycemic control was determined monthly by recording the glycohemoglobin, total daily insulin requirements, and fasting blood glucoses. Beta-cell function was measured by determining the C-peptide response to a mixed formula meal (Sustacal) at baseline and at 1,3,6,9, and 12 months after treatment. The area under the curve (AUC) of the C-peptide response was calculated and, to reduce variability, related to that of the same subject at baseline. An analysis of subjects who retained at least 80% of their baseline beta-cell function as measured by the AUC was performed.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗