DPD epitope-specific glutamic acid decarboxylase (GAD)65 autoantibodies in children with Type 1 diabetes

AIM

To study whether DPD epitope-specific glutamate decarboxylase autoantibodies are found more frequently in children with milder forms of Type 1 diabetes.

METHODS

We prospectively evaluated 75 children with new-onset autoimmune Type 1 diabetes, in whom we collected demographic, anthropometric and clinical data and measured islet autoantibodies. Glutamate decarboxylase 65 autoantibody-positive samples were analysed for epitope specificities using recombinant Fab against the DPD-defined epitope of glutamate decarboxylase 65.

RESULTS

After adjustment for age, positive DPD epitope recognition was significantly associated with higher C-peptide levels at onset (P = 0.02, r² =0.21, n = 35), and high DPD recognition in the highest quartile tended to be associated with HbA_1c ≤ 53 mmol/mol (7%) at the last follow-up [mean (sd) follow-up 1.3 (0.4) years; P = 0.07; for the model, P = 0.044, n = 30)]. Age- and sex-adjusted BMI percentile was significantly correlated with recognition of the DPD-defined epitope (P < 0.03, r² =0.14, n = 34), but this correlation was driven by the older age group (age ≥ 10 years; P = 0.016, r² =0.27, n = 21) and was not significant in younger children (P = 0.93, n = 13). There were no independent associations with sex, race/ethnicity, diabetic ketoacidosis, HbA_1c , HLA DR3-DQ2/DR4-DQ8 or autoantibody number.

CONCLUSIONS

Our findings suggest that recognition of the DPD-defined glutamate decarboxylase 65 autoantibody epitope at Type 1 diabetes onset is directly associated with β-cell function, BMI and age, which supports the hypothesis that immunological factors contribute to the clinical heterogeneity of Type 1 diabetes. Larger studies relating epitope-specific glutamate decarboxylase 65 autoantibody to clinical phenotype in children with Type 1 diabetes are warranted.

Design, synthesis, and biological evaluation of analogues of the antitumor agent, 2-(4-[(7-chloro-2-quinoxalinyl)oxy]phenoxy)propionic acid (XK469)

2-(4-[(7-Chloro-2-quinoxalinyl)oxy]phenoxy)propionic acid (XK469) is among the most highly and broadly active antitumor agents to have been evaluated in our laboratories and is currently scheduled to enter clinical trials in 2001. The mechanism or mechanisms of action of XK469 remain to be elaborated. Accordingly, an effort was initiated to establish a pharmacophore hypothesis to delineate the requirements of the active site, via a comprehensive program of synthesis of analogues of XK469 and evaluation of the effects of structural modification(s) on solid tumor activity. The strategy formulated chose to dissect the two-dimensional parent structure into three regions-I, ring A of quinoxaline; II, the hydroquinone connector linkage; and III, the lactic acid moiety-to determine the resultant in vitro and in vivo effects of chemical alterations in each region. Neither the A-ring unsubstituted nor the B-ring 3-chloro-regioisomer of XK469 showed antitumor activity. The modulating antitumor effect(s) of substituents of differing electronegativities, located at the several sites comprising the A-ring of region I, were next ascertained. Thus, a halogen substituent, located at the 7-position of a 2-(4-[(2-quinoxalinyl)oxy]phenoxy)propionic acid, generated the most highly and broadly active antitumor agents. A methyl, methoxy, or an azido substituent at this site generated a much less active structure, whereas 5-, 6-, 8-chloro-, 6-, 7-nitro, and 7-amino derivatives all proved to be essentially inactive. When the connector linkage (region II) of 1 was changed from that of a hydroquinone to either a resorcinol or a catechol derivative, all antitumor activity was lost. Of the carboxylic acid derivatives of XK469 (region III), i.e., CONH2, CONHCH3, CON(CH3)2, CONHOH, CONHNH2, CN, or CN4H (tetrazole), only the monomethyl- and N,N-dimethylamides proved to be active.

Preclinical efficacy of thioxanthone SR271425 against transplanted solid tumors of mouse and human origin

A highly active and broadly active thioxanthone has been identified: N-[[1-[[2-(Diethylamino)ethyl]amino]-7-methoxy-9-oxo-9H-thioxanthen++ +-4-yl] methylformamide (SR271425, BCN326862, WIN71425). In preclinical testing against a variety of subcutaneously growing solid tumors, the following %T/C and Log10 tumor cell kill (LK) values were obtained: Panc-03 T/C = 0, 5/5 cures; Colon-38 (adv. stage) T/C = 0, 3/5 cures, 4.9 LK; Mam-16/C T/C = 0, 3.5 LK; Mam-17/0 T/C = 0, 2.8 LK; Colon-26 T/C = 0, 1/5 cures, 3.2 LK; Colon-51 T/C = 0, 2.7 LK; Panc-02 T/C = 0, 3.1 LK; B16 Melanoma T/C = 13%, 4.0 LK; Squamous Lung-LC12 (adv. stage) T/C = 14%, 4.9 LK; BG-1 human ovarian T/C = 16%, 1.3 LK; WSU-Brl human breast T/C = 25%, 0.8 LK. The agent was modestly active against doxorubicin (Adr)-resistant solid tumors: Mam-17/AdrT/C =23%, 0.8 LK; and Mam-16/C/Adr T/C = 25%, 1.0 LK, but retained substantial activity against a taxol-resistant tumor: Mam-16/C/taxol T/C = 3%, 2.4 LK. SR271425 was highly active against IV implanted leukemias, L1210 6.3 LK and AML1498 5.3 LK. The agent was equally active both by the IV and oral routes of administration, although requiring approximately 30% higher dose by the oral route. Based on its preclinical antitumor profile, it may be appropriate to evaluate SR271425 in clinical trials.

Aberrant expression of cyclin A and cyclin B1 proteins in oral carcinoma

Cyclins play an important role in regulating the passage of dividing cells through critical checkpoints in the cell cycle. Aberrant expression of cyclin proteins has been found in a number of human cancers, including carcinomas of the head and neck, where amplification of the cyclin D1 gene is a common finding. The objective of this study was to examine cell cycle kinetics in oral carcinomas by determining the expression of the S phase protein cyclin A and the M phase protein cyclin B1. Routinely processed tissue sections of 50 oral squamous cell carcinomas from the floor of the mouth were stained by immunohistochemistry for cyclin A, cyclin B1 and Ki-67 proteins. Ten specimens of normal epithelium from the floor of the mouth were used as controls. The number of cells showing nuclear staining for cyclin A, cyclin B1 and Ki-67 proteins was determined by computer image analysis. There were 17 well-differentiated, 25 moderately differentiated and 8 poorly differentiated tumours. Mean counts for cyclin A (29.50+/-4.10, mean+/-95% CI), cyclin B1 (2.05+/-0.30) and Ki-67 (49.46+/-5.91) proteins in the carcinomas were significantly higher than counts for the normal epithelial controls (cyclin A: 9.30+/-1.72; cyclin B1: 1.01+/-0.36; Ki-67: 17.40+/-4.17). For cyclin A, cyclin B1 and Ki-67, mean staining scores for all tumour grades were significantly higher than controls. There was a strong correlation between Ki-67 and cyclin A scores in all tumour groups (r2=0.68); however, the correlations between cyclin B1 and cyclin A scores (r2=0.35) and between cyclin B1 and Ki-67 scores (r2= 0.39) were weak. We conclude that there is overexpression of cyclin A and cyclin B1 proteins in oral carcinoma. Furthermore, the poor correlations for cyclin B1 scores with other cell cycle indices suggest that there may be aberrant cell cycle progression at the G2/M checkpoint in oral carcinomas.

Preclinical antitumor efficacy of analogs of XK469: sodium-(2-[4-(7-chloro-2-quinoxalinyloxy)phenoxy]propionate

A series of quinoxaline analogs of the herbicide Assure was found to have selective cytotoxicity for solid tumors of mice in a disk-diffusion-soft-agar-colony-formation-assay compared to L1210 leukemia. Four agents without selective cytotoxicity and 14 agents with selective cytotoxicity were evaluated in vivo for activity against a solid tumor. The four agents without selective cytotoxicity in the disk-assay were inactive in vivo (T/C > 42%). Thirteen of the fourteen agents with selectivity in the disk-assay were active in vivo (T/C < 42%). Five of the agents had curative activity. These five agents had a halogen (F, Cl, Br) in the 7-position (whereas Assure had a CI in the 6 position). All agents with curative activity were either a carboxylic acid, or a derivative thereof, whereas Assure is the ethyl ester of the carboxylic acid. All other structural features were identical between Assure and the curative agents. Assure had no selective cytotoxicity for solid tumors in the disk-assay, and was devoid of antitumor activity. The analog XK469 is in clinical development.

Discovery of cryptophycin-1 and BCN-183577: examples of strategies and problems in the detection of antitumor activity in mice

Historically, many new anticancer agents were first detected in a prescreen; usually consisting of a molecular/biochemical target or a cellular cytotoxicity assay. The agent then progressed to in vivo evaluation against transplanted human or mouse tumors. If the investigator had a large drug supply and ample resources, multiple tests were possible, with variations in tumor models, tumor and drug routes, dose-decrements, dose-schedules, number of groups, etc. However, in most large programs involving several hundred in vivo tests yearly, resource limitations and drug supply limitations have usually dictated a single trial. Under such restrictive conditions, we have implemented a flexible in vivo testing protocol. With this strategy, the tumor model is dictated by in vitro cellular sensitivity; drug route by water solubility (with water soluble agents injected intravenously); dosage decrement by drug supply, dose-schedule by toxicities encountered, etc. In this flexible design, many treatment parameters can be changed during the course of treatment (e.g., dose and schedule). The discovery of two active agents are presented (Cryptophycin-1, and Thioxanthone BCN 183577). Both were discovered by the intravenous route of administration. Both would have been missed if they were tested intraperitoneally, the usual drug route used in discovery protocols. It is also likely that they would have been missed with an easy to execute fixed protocol design, even if injected i.v.

Patterns of p53 and Ki-67 protein expression in epithelial dysplasia from the floor of the mouth

Oral squamous cell carcinoma develops through a series of precancerous stages manifested at the microscopic level as epithelial dysplasia. Mutation of the p53 tumour suppressor gene is thought to be an important component of oral carcinogenesis. p53 regulates cell proliferation and DNA repair by inhibiting the cell cycle at G1/S; loss of p53 function may therefore lead to aberrant cell kinetics. To date, no studies have examined the relationship between p53 protein and alterations in cell kinetics in oral epithelial dysplasia from a single anatomical site. Serial sections were studied from 40 routinely processed biopsy specimens of epithelial dysplasia from the floor of the mouth. The expression of p53 protein was determined by immunohistochemistry and cell proliferation was studied by immunostaining for the cell cycle-dependent protein Ki-67. The number of positive cells per millimetre of basement membrane was determined using computer image analysis and compared with site-matched normal controls. The mean p53 labelling index (LI) in normal mucosa was low, 3.48 +/- 0.92 [mean +/- 95 per cent confidence interval (CI)], and increased sharply in the transition from mild (42.49 +/- 21.71) to moderate (104.86 +/- 51.39) epithelial dysplasia. The mean p53 LI for severe dysplasia was 119.09 +/- 56.50. Differences were also observed in the distribution of p53-positive cells between grades of dysplasia, with the development of compact p53-positive foci in severe dysplasia. Mean proliferative indices, as determined by Ki-67 expression, were significantly associated with grade of epithelial dysplasia. Furthermore, there was a significant correlation between p53 LI and Ki-67 score (r2 = 0.37, P = 0.01). It is concluded that altered p53 protein expression is probably an early event in oral carcinogenesis in the floor of the mouth and is associated with dysregulation of cell proliferation at this site.

Preparing to tack: when physicians change careers

Because of the progressive health care revolution that gives all the power to the managed care insurance companies, the usurpation of physician autonomy, and the replacement of the physician-patient relationship with HMO policies, doctors are looking at other career choices. Many doctors have never considered life after medicine and have made no plans for that time in their future. Despite their ample education, some doctors say, "I don't know how to do anything else. I am trapped in this system, and I can't get out. If I knew what else I could do, I would definitely change careers." Many doctors feel that it is too late in their lives to make such a change. However, it is becoming more and more acceptable to switch or modify a medical career. A number of physicians have switched careers successfully without disgrace and have discovered that there is indeed a life after the first career choice. It isn't always easy, but it can be done.

Identification of amino acid changes affecting yeast uroporphyrinogen decarboxylase activity by sequence analysis of hem12 mutant alleles

The molecular basis of the uroporphyrinogen decarboxylase defect in eleven yeast 'uroporphyric' mutants was investigated. Uroporphyrinogen decarboxylase, an enzyme of the haem-biosynthetic pathway, catalyses the decarboxylation of uroporphyrinogen to coproporphyrinogen and is encoded by the HEM12 gene in the yeast Saccharomyces cerevisiae. The mutations were identified by sequencing the mutant hem12 alleles amplified in vitro from genomic DNA extracted from the mutant strains. Four mutations leading to the absence of enzyme protein were found: one mutation caused the substitution of the translation initiator Met to Ile, a two-base deletion created a frameshift at codon 247 and two nonsense mutations were found at codons 50 and 263. Four different point mutations were identified in seven 'leaky' mutants with residual modified uroporphyrinogen decarboxylase activity; each of three mutations was found in two independently isolated mutants. The nucleotide transitions resulted in the amino acid substitutions Ser-59 to Phe, Thr-62 to Ile, Leu-107 to Ser, or Ser-215 to Asn, all located in or near highly conserved regions. The results suggest that there is a single active centre in uroporphyrinogen decarboxylase, the geometry of which is affected in the mutant enzymes.

Uroporphyrinogen decarboxylase in Saccharomyces cerevisiae. HEM12 gene sequence and evidence for two conserved glycines essential for enzymatic activity

The HEM12 gene from Saccharomyces cerevisiae encodes uroporphyrinogen decarboxylase which catalyzes the sequential decarboxylation of the four acetyl side chains of uroporphyrinogen to yield coproporphyrinogen, an intermediate in protoheme biosynthesis. The gene was isolated by functional complementation of a hem12 mutant. Sequencing revealed that the HEM12 gene encodes a protein of 362 amino acids with a calculated molecular mass of 41,348 Da. The amino acid sequence shares 50% identity with human and rat uroporphyrinogen decarboxylase and shows 40% identity with the N-terminus of an open reading frame described in Synechococcus sp. We determined the sequence of two hem12 mutations which lead to a totally inactive enzyme. They correspond to the amino acid changes Gly33----Asp and Gly300----Asp, located in two evolutionarily conserved regions. Each of these substitutions impairs binding of substrates without affecting the overall conformation of the protein. These results argue that a single active center exists in uroporphyrinogen decarboxylase.

Prevalence of the 281 (Gly----Glu) mutation in hepatoerythropoietic porphyria and porphyria cutanea tarda

The prevalence of the 281 (Gly----Glu) mutation in hepatoerythropoietic porphyria (HEP) was investigated by the use of hybridization with a synthetic oligonucleotide probe. The mutation was found in HEP-affected members of two unrelated families from Spain, but was absent in two other patients from Italy and Portugal who also had HEP. Moreover, this mutation was not detected in 13 unrelated cases of familial (type II) porphyria cutanea tarda.

Molecular cloning and nucleotide sequence of a complete human uroporphyrinogen decarboxylase cDNA

We have cloned and sequenced a full-length cDNA coding for human uroporphyrinogen decarboxylase. The deduced 367-amino acid sequence is consistent with the molecular weight, the partial amino acid sequence of cyanogen bromide peptides, and the total amino acid composition of the purified enzyme. Southern analysis of human genomic DNA shows that its gene is present as a single copy in the human genome, and Northern analysis demonstrates the presence of a single size species of mRNA in erythroid and non-erythroid tissues and in several cultured cell lines. We have also demonstrated that the level of uroporphyrinogen decarboxylase mRNA is markedly increased in tissues or cell lines of erythroid origin and that this is due to a tissue-specific transcriptional activation of the uroporphyrinogen decarboxylase gene.

Studies on the pathology of non-Hodgkin's lymphoma of childhood. I. The role of routine histopathology as a prognostic factor. A report from the Children's Cancer Study Group

Between April 1977, and August 1980, the Children's Cancer Study Group (CCSG) conducted a clinical trial of childhood non-Hodgkin's lymphoma (NHL), randomizing 256 patients to one of two treatment regimens. A 4-drug regimen (regimen 1, modified cyclophosphamide, Oncorin [vincristine], methotrexate, prednisone [COMP] ) was compared with a 10-drug regimen (regimen 2, modified LSA2-L2). Using the Rappaport classification, the review pathologist diagnosed the 213 evaluable tissue specimens as follows: lymphoblastic (LC), 73; Burkitt's tumor (BT), 40; "undifferentiated" non-Burkitt's type (NB), 67; large cell or "histiocytic" lymphoma (HI), 29; and other types (OT), 4. Concurrence in classification between the review and institutional pathologists was poor when using the above four categories; however, concurrence was 88% between the review pathologist and other hematopathologists, and 99% when classifying the specimens as lymphoblastic or nonlymphoblastic. For patients with nonlocalized disease, this randomized controlled study demonstrated a new important correlation of histopathology with the effectiveness of treatment. When analyzed without stratification into lymphoblastic and nonlymphoblastic types, the two regimens showed identical relapse free survival (RFS) curves for patients with nonlocalized involvement. However, when patients were stratified according to histologic classification, regimen 2 was superior to regimen 1 for patients with lymphoblastic lymphoma, achieving 74% RFS at 30 months compared to 31% for regimen 1 (P = 0.001). Conversely, those with nonlymphoblastic types (BT, NB, HI) treated with regimen 1 had a 58% RFS at 30 months compared to 32% for those treated on regimen 2 (P = 0.01). This study demonstrates that proper, routine histopathologic classification of NHL is the best criterion for choice of therapy in children with nonlocalized involvement. As a result of this study, all patients with nonlocalized disease, diagnosed after August 1980, were no longer randomized but were assigned to the appropriate treatment regimen based on prospective review of histopathology.

Childhood non-Hodgkin's lymphoma. The results of a randomized therapeutic trial comparing a 4-drug regimen (COMP) with a 10-drug regimen (LSA2-L2)

Members of the Childrens Cancer Study Group treated 234 eligible patients in a randomized trial designed to study the relative effectiveness of two therapy programs for the treatment of childhood and adolescent non-Hodgkin's lymphoma. Two chemotherapeutic strategies were compared: a 4-drug regimen (COMP) and a 10-drug regimen (modified LSA2-L2). Failure-free survival for all patients was 60 per cent at 24 months. In patients with disseminated disease treatment success was influenced by both the histologic subtype of disease and the therapeutic regimen followed. The 10-drug program was more effective than the 4-drug program in patients with disseminated lymphoblastic disease (two-year failure-free survival rate, 76 vs. 26 per cent, respectively; P = 0.0002), whereas the 4-drug program was more effective than the 10-drug program in those with nonlymphoblastic disease (57 vs. 28 per cent, respectively, P = 0.008). The less toxic, more easily administered 4-drug regimen was as effective as the 10-drug regimen in patients with localized disease (89 vs. 84 per cent, respectively).

Histiocytosis X: occurrence and oral involvement in six adolescent and adult patients

Six cases of adolescent- and adult-onset histiocytosis X with oral involvement and their evaluation are described. Clinical findings can be mistaken for dental infection. Management involved a combination of low-dose radiation and chemotherapeutic drugs. The extreme variability of clinical signs and symptoms and the extent and progression of the disease suggest that the classic classification of histiocytosis X is inappropriate.

Brainstem hemorrhages and increased intracranial pressure: from Duret to computed tomography

In the late nineteenth century, Henri Duret produced minute brainstem hemorrhage in dogs by rapidly increasing their intracranial pressure. Whether those hemorrhages were the same as those seen today associated with transtentorial herniation is not agreed upon, and the term Duret's hemorrhages is rarely used. Duret's report on his experiments is condensed here and the value of computed tomography for detecting brainstem hemorrhages is illustrated by a case report.

A new therapy schedule for pediatric non-Hodgkin lymphoma toxicity with preliminary results

A pilot study of the toxicity and efficacy of a new treatment schedule for childhood non-Hodgkin's lymphoma was conducted by members of the Children's Cancer Study Group (CCSG) prior to its use in a randomized phase III trial. Chemotherapeutic agents used were cyclophosphamide (CPM), vincristine (VCR), and prednisone, together with intravenous (IV) and intrathecal methotrexate (IT MTS). Radiation therapy was also employed. From September 1976 to April 1977, 27 eligible, newly diagnosed patients with non-Hodgkin's lymphoma were entered onto this pilot study. Toxicity was acceptable with minor adjustments in dosage and timing of the myelosuppressive agents. Fourteen of the 22 patients entered onto maintenance remain entirely disease-free, and all have completed the prescribed course of chemotherapy. None of the 12 patients characterized as having a "favorable" prognosis has relapsed, with a median follow-up of 27 months from on study.

Crouzon's disease (craniofacial dysostosis). Modern diagnosis and treatment

✓ This article discusses the nature and treatment of Crouzon's disease and reproduces a translation of part of Crouzon's original description. Six typical patients with this disease are presented, and the reasons for surgical treatment emphasized.

Neonatal intracranial choriocarcinoma. Case report

✓ A case is reported of a newborn child whose predominant lesion was a metastatic choriocarcinoma of the brain. The outstanding features of the clinical course were repeated episodes of intracranial and subgaleal hemorrhage. Angiograms revealed large areas of pooling of contrast medium without neovascularization or rapid venous drainage. A review of the literature demonstrated the infrequency with which this lesion has been encountered.

Kyphoscoliosis following lumbar subarachnoid shunts

✓ In a follow-up of 80 lumbar subarachnoid shunts for hydrocephalus, scoliosis with limitation of back flexion was found to have developed in approximately 50% of the surviving children, some of whom showed a disparity in the length and size of their legs. There was no correlation between the direction of the convexity of the scoliosis and the side of the shortened leg, or between the number of shunt revisions and the ultimate development of kyphoscoliosis, or between removal of laminae and the subsequent development of scoliosis. Three case histories are presented to illustrate the still unproven but possible relationship between arachnoiditis due to polyethylene tubes and the ensuing scoliosis. Removal of the lumbar shunts, decompression, and laminectomy seemed to have no beneficial effect in the reversal of the scoliosis in any of the cases reviewed.