Termination of damaged protein repair defines the occurrence of symptoms in carriers of the m.3243A > G tRNA(Leu) mutation.

BACKGROUND: The m.3243A>G mutation in the mitochondrial tRNA(Leu(UUR)) gene is an example of a mutation causing a very heterogeneous phenotype. It is the most frequent cause (80%) of the MELAS syndrome (mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes), but it can also lead in addition or separately to type 2 diabetes, deafness, renal tubulopathy and/or cardiomyopathy. METHODS: To identify pathogenic processes induced by this mutation, we compared global gene expression levels of muscle biopsies from affected and unaffected mutation carriers with controls. RESULTS AND CONCLUSIONS: Gene expression changes were relatively subtle. In the asymptomatic group 200 transcripts were upregulated and 12 were downregulated, whereas in the symptomatic group 15 transcripts were upregulated and 52 were downregulated. In the asymptomatic group, oxidative phosphorylation (OXPHOS) complex I and IV genes were induced. Protein turnover and apoptosis were elevated, most likely due to the formation of dysfunctional and reactive oxygen species (ROS) damaged proteins. These processes returned to normal in symptomatic patients. Components of the complement system were upregulated in both groups, but the strongest in the symptomatic group, which might indicate muscle regeneration--most likely, protein damage and OXPHOS dysfunction stimulate repair (protein regeneration) and metabolic adaptation (OXPHOS). In asymptomatic individuals these processes suffice to prevent the occurrence of symptoms. However, in affected individuals the repair process terminates, presumably because of excessive damage, and switches to muscle regeneration, as indicated by a stronger complement activation. This switch leaves increasingly damaged tissue in place and muscle pathology becomes manifest. Therefore, the expression of complement components might be a marker for the severity and progression of MELAS clinical course.

Altered myocardial gene expression reveals possible maladaptive processes in heterozygous and homozygous cardiac myosin-binding protein C knockout mice.

Familial hypertrophic cardiomyopathy (FHC) is an autosomal dominant disease characterized by left ventricular hypertrophy (LVH) predominantly affecting the interventricular septum. Cardiac myosin-binding protein C (cMyBP-C) mutations are common causes of FHC. Gene expression profiling was performed in left ventricles of 9-week-old wild-type mice, heterozygous cMyBP-C KO mice displaying asymmetric septal hypertrophy, and homozygous mice developing eccentric LVH. Knocking out one or two cMyBP-C genes leads primarily to gene expression changes indicating an increased energy demand, activation of the JNK and p38 parts of the MAPK pathway and deactivation of the ERK part, and induction of apoptosis. Altered gene expression for processes related to cardiac structure, contractile proteins, and protein turnover was also identified. Many of the changes were more pronounced in the homozygous KO mice. These alterations point to physiological and pathological adaptations in the prehypertrophic heterozygous KO mice and the hypertrophic homozygous mice.

Monoclonal antibodies to a rat colon carcinoma: model for monoclonal antibody therapy of solid tumors.

Tumor progression, lung metastasis, and death occur in tumor-bearing BD IX syngeneic rats in a fashion similar to the course of patients with metastatic colon cancer. In an effort to establish a relevant model for monoclonal antibody (MoAb) therapy of tumors, we generated murine MoAb against DHD/TR, a dimethylhydrazine-induced rat colon carcinoma which has been adapted to cell culture. Murine MoAb 17B10 E4 (E4) reacts with the TR tumor and shows weak immunoperoxidase reactivity with normal rat tissues. Murine MoAb 5F7 D3 (D3) reacts with the tumor and a variety of normal rat epithelia. Both are IgG2a and mediate cytotoxicity by rat peripheral blood mononuclear cells. 18D5 F6 (F6) also reacts with the tumor and normal tissues but is an IgG2b and does not mediate cytotoxicity in the presence of rat effector cells. Iodinated E4 and D3 antibodies retained their immunoreactivity. E4 revealed 9.8 x 10(5) antigenic sites per TR cell, with an affinity constant of 9.35 x 10(7) M-1, while D3 demonstrated 2.5 x 10(6) antigenic sites and an affinity constant of 4.2 x 10(7) M-1. Immunoblotting showed that the antigens recognized by D3 and E4 are glycoproteins with molecular weights of 27,000 and 66,000, respectively. F6 failed to react with its antigen present in the blot. This rat colon carcinoma and the monoclonal antibodies described here may provide experimental data useful for implementing monoclonal antibodies in cancer therapy.

DNA microarrays for comparison of gene expression profiles between diagnosis and relapse in precursor-B acute lymphoblastic leukemia: choice of technique and purification influence the identification of potential diagnostic markers.

Microarrays for gene expression profiling are rapidly becoming important research tools for the identification of novel markers, for example, for novel classification of leukemias and lymphomas. Here, we review the considerations and infrastructure for microarray experiments. These considerations are illustrated via a microarray-based comparison of gene expression profiles of paired diagnosis-relapse samples from patients with precursor-B acute lymphoblastic leukemia (ALL), who relapsed during therapy or after completion of treatment. Initial experiments showed that several seemingly differentially expressed genes were actually derived from contaminating non-leukemic cells, particularly myeloid cells and T-lymphocytes. Therefore, we purified the ALL cells of the diagnosis and relapse samples if their frequency was lower than 95%. Furthermore, we observed in earlier studies that extra RNA amplification leads to skewing of particular gene transcripts. Sufficient (non-amplified) RNA of purified and paired diagnosis-relapse samples was obtained from only seven cases. The gene expression profiles were evaluated with Affymetrix U95A chips containing 12 600 human genes. These diagnosis-relapse comparisons revealed only a small number of genes (n=6) that differed significantly in expression: mostly signaling molecules and transcription factors involved in cell proliferation and cell survival were highly upregulated at relapse, but we did not observe any increase in drug-resistance markers. This finding fits with the observation that tumors with a high proliferation index have a poor prognosis. The genes that changed between diagnosis and relapse are currently not in use as diagnostic or disease progression markers, but represent potential new markers for such applications. Leukemia (2003) 17, 1324-1332. doi:10.1038/sj.leu.2402974

In vitro studies in nickel allergy: diagnostic value of a dual parameter analysis.

A comparison was made between the diagnostic value of assaying nickel-induced lymphocyte proliferation (lymphocyte transformation test, LTT) and migration inhibition factor (MIF) production in nickel contact sensitivity. Although lymphocyte proliferation was significantly increased in the group of patients with skin test reactivity to nickel, positive LTT were also frequently found in skin test-negative subjects: in 63% of subjects with and in 30% of subjects without a history of metal allergy. This would limit the value of the LTT as an in vitro correlate of skin test reactivity. However, in certain patients positive lymphocyte transformation may reveal nickel sensitization at a time of undetectable skin reactivity. Data obtained with the macrophage migration inhibition test (MMIT) showed a good correlation with nickel patch test reactions. Accurate determination of MIF became feasible by using cells from the human monocytoid cell line U937 as target cells in a microdroplet agarose assay. Using this MMIT, positive reactions occurred in 13% of the healthy controls and false-negative reactions were found in 26% of patients with positive skin test reactivity to nickel. As LTT and MMIT data appeared to be only weakly correlated in the individuals tested, a dual parameter analysis was performed. An excellent correlation [p = 1.8 (10(-8]] was found between skin test and in vitro reactivity for individuals with matching in vitro results (60% of all individuals tested). In those individuals with discordant in vitro data, skin testing will remain indispensable for diagnosing nickel allergy.

Newborn minor physical anomalies and problem behavior at age three.

The authors followed up 136 three-year-olds who had high or low scores for minor physical anomalies of face, head, hands, and feet at birth. Interviews with parents revealed that high-anomaly infants were somewhat more likely to have problem behaviors at age three; this was particularly true for hyperactive-impulsive behavior for boys. Preschool teachers' ratings of hyperactivity, however, did not show a significant relationship to anomaly score. The results suggest some congenital contributors to behavior disorders of childhood, but the relationship between anomalies and problem behavior is weak and limits clinical usefulness of this measure when used alone for identifying a high-risk population.

Cerebrospinal fluid neuron-specific enolase is reduced in Alzheimer's disease.

Neuron-specific enolase (NSE), a glycolytic enzyme enolase found in brain, was examined in the cerebrospinal fluid and serum of 30 patients with presumptive Alzheimer's disease (AD) and of 13 healthy controls and evaluated as a measure of neuronal functional activity associated with AD. The cerebrospinal fluid NSE levels of patients with AD were significantly reduced and serum NSE levels were significantly increased from controls. Cerebrospinal fluid NSE levels may be representative of central nervous system cell loss or a decrease in neuronal functional activity associated with AD.

Pharmacokinetic studies of mouse monoclonal antibodies to a rat colon carcinoma: I. Comparison of biodistribution in normal rats, syngeneic tumor-bearing rats, or tumor-bearing nude mice.

The pharmacokinetics of two iodine-131-(131I) labeled murine anti-rat colon carcinoma monoclonal antibodies (D3 and E4) were compared in normal Sprague Dawley rats, syngeneic BDIX rats, or nude mice bearing that tumor. Results of antibody uptake after i.v. administration were analyzed in terms of accumulation and localization indices for normal tissues and tumor. Statistically significant differences between rat and mouse tissue biodistribution were found. D3, which reacts in vitro with the tumor and several normal rat tissues, cleared quickly from the blood of rats and was specifically targeted to several normal tissues, notably the lung. Virtually no targeting to the tumor was observed. Nude mice, however, showed a slower blood clearance and specific antibody targeting only in the tumor. Similar results were seen after injection of another antibody, E4, which is tumor-specific in vitro. Data suggest that studies on the xenogeneic nude mouse model may not necessarily be relevant to the choice of monoclonal antibodies for clinical diagnostic imaging or therapy.

Effects of stress on amino acids and related compounds in various tissues of fasted rats.

The purpose of this study was to examine the effect of stress on the free amino acid pattern of plasma and various organs. Two groups of rats were deprived of food, for 24 hrs. One group was sacrificed after this time (fasting control representing mostly free endogenous amino acids) and the second group was first restrained in wire cages for 120 min before being sacrificed (fasting stress representing mostly the effects of stress on endogenous free amino acids). A third group had free access to food and was sacrificed at the same time (fed control representing mostly free amino acids absorbed from the gut and endogenous free amino acid metabolism). Fasting (as compared to fed controls) reduced alanine and arginine but increased ethanolamine, glutamic acid and glutamine in the plasma; increased ethanolamine, phosphoethanolamine and glutamic acid in the liver; increased carnosine, glutamic acid, phosphoethanolamine and glutamine in the ventricle; increased oxidized glutathione in the aorta; decreased alanine, aspartic acid, glutamic acid, leucine and methionine and increased glutamine in the pancreas; and decreased arginine in skeletal muscle. Fasting plus stress (as compared to fasting controls) reduced alanine and glutamine in the plasma; increased methionine in the liver; increased ethanolamine, GABA, and glutamic acid in the aorta; reduced arginine, glutamic acid, glutamine, leucine and methionine but increased ethanolamine in the ventricle; reduced ammonia and ethanolamine but increased histidine, isoleucine, leucine, lysine, phenylalanine, tyrosine and valine in the pancreas; and reduced ammonia in skeletal muscle. Fasting plus stress affects the amino acid composition of plasma and various of tissues but effects seen were individually different and strongly substance and tissue specific. Plasma changes did not coincide with tissue changes. Changes in the endogenous pattern of amino acids and related compounds in response to stress could be first indications of stress induced organ pathology.

Stability and comparability of intellectual measures for cerebral-palsied preschoolers.

Intelligence test scores on the Stanford-Binet Intelligence Scale and the Merrill Palmer Scale were studied for 23 cerebral-palsied children to determine the stability and comparability of these measures during the preschool years as well as the relationship of pyschological gains or losses to clinical diagnoses of the children. Test and posttest data were analyzed for subjects who had participated for one year in a special preschool program for children with neuromotor problems. A high correlation was found between the two intelligence tests both on pretesting (r = .89) and posttesting (r = .83). No significant differences were observed between IQs attained at the three-year level and IQs attained at the four-year level. No associative pattern between etiology of the disability, neuromotor involvement, and intelligence test patterns was determined.

Failure of monoclonal antibodies against tumor associated antigens to improve tumor targeting of LAK cells in a model of rat colon carcinoma.

The possibility of targeting LAK cells to the tumor by arming them with monoclonal antibodies directed against tumor associated antigens was tested in a rat model of colon carcinoma. Peritoneal carcinomatosis was generated by injection of cloned tumor cells and 111In-labeled LAK cells were injected in the tail vein after preincubation with the monoclonal antibodies themselves. It appeared that the antibodies did not significantly improve tumor targeting of LAK cells, most of the radioactivity being recovered in the spleen, the liver, the kidney or the lung, and only a small fraction in the tumor.

[Characterization of autoantigen (p105) in a model of colonic adenocarcinoma in the rat]. / Caractérisation d'un autoantigène (p105) dans un modèle d'adénocarcinome colique chez le rat.

Sera from BDIX rats bearing the syngeneic colon tumors PROb or REGb were analysed by Western blotting in order to detect a possible humoral response against the grafted tumor. The PROb clone grows progressively in syngeneic hosts and metastasizes, whereas the REGb clone grows slowly and then is rejected. This model was developed by F Martin and his group in Dijon, France. We observed that rats bearing PROb tumors only develop an antibody response against a water-soluble protein of 105 kDa (p105) which is expressed by both tumor clones. This antibody response has never been detected in rats bearing REGb tumors. The antigen p105 was also expressed by normal adult colon as well as some other foetal or adult tissues. It is also present in extracts from several tumor cell lines including human colorectal carcinoma cell lines. Moreover, the titer of detected antibody at day 30 was inversely correlated with the survival of rats after tumor inoculation, suggesting a possible facilitating role of this antibody response.

Early and transient gene expression changes in pressure overload-induced cardiac hypertrophy in mice.

Cardiac hypertrophy is an important risk factor for cardiac morbidity and mortality. To unravel the underlying pathogenic genetic pathways, we hybridized left ventricular RNA from Transverse Aortic Constriction mice at 48 h, 1 week, and 2, 3, and 8 weeks after surgery to microarrays containing a 15K fetal cDNA collection. Key processes involved an early restriction in the expression of metabolic genes, accompanied by increased expression of genes related to growth and reactivation of fetal genes. Most of these genes returned to basal expression levels during the later, compensated hypertrophic phase. Our findings suggest that compensated hypertrophy in these mice is established by rapid adaptation of the heart at the cost of gene expression associated with metabolic activity, with only temporary expression of possible maladaptive processes. Therefore, the transient early changes may reflect a beneficial response to pressure overload, as deterioration of cardiac hemodynamic function or heart failure does not occur.

Newborn minor physical anomalies and prediction of infant behavior.

The relationship between a newborn score of minor physical anomalies (MPAs) and behavior at ages 1 and 2 was examined. From an initial screening population of 933, 63 high anomaly and 78 low anomaly infants were followed until age 2 by examiners blind for the newborn anomaly score. High anomaly infants were more likely to be temperamentally difficult as rated by parent interview and direct observation. A subgroup of six infants who were considered irritable at both ages 1 and 2 were all from the high anomaly group. However, there was little agreement between behavioral ratings across situations and over time, and there were no significant predictors of behavior problems at age 2 based on any newborn or 1-year measure. These results indicate that the newborn anomaly score by itself is unlikely to prove clinically useful in predicting preschool behavior problems for an unselected population. The usefulness of this measure for other, "high-risk," populations remains to be explored.