Strand asymmetry of CpG transitions as indicator of G1 phase-dependent origin of multiple tumorigenic p53 mutations in stem cells

In dividing cells, expression of mutations is DNA strand symmetric. Of all mutations originating de novo in nondividing cells, only those in the transcribed (noncoding) strand are immediately expressed in mRNA and protein. In contrast, any new mutation in the nontranscribed (coding) strand remains unexpressed until the cells enter S phase and begin proliferation. This previously unrecognized difference enables us to examine the cell cycle-dependent origin of multiple tumorigenic mutations in stem cells. The human p53 gene, which acts as a gatekeeper in the control of G1 to S phase transition, was chosen for the analysis. Of all multiple mutations contained in p53 databases, we have tested in detail CpG transitions. Three features of CpG sites dictate this choice: C --> T transitions at methylated mCpG are the direct product of mC deamination and are replication-independent; it is easy to identify the strand bearing a primary mC --> T event because C --> T on the transcribed strand appears as G --> A on the nontranscribed strand; and CpG transitions are the most frequent (as both singular and multiple occurrences) tumor-related p53 mutations. The origin of double nonsilent CpG transitions in nondividing cells predicts a significant excess of the heterostrand (C --> T, G --> A) doublets over the homostrand (C --> T, C --> T and G --> A, G --> A) doublets. For p53, we found such an excess. Based on this result, along with the results of three other tests reported here, we conclude that the majority of multiple p53 mutations from human tumors occurred in quiescent stem cells.     

The pre-clinical assessment of QT interval prolongation: a comparison of in vitro and in vivo methods

The literature was searched for in vivo dog studies reporting QT prolongation and in vitro studies reporting increased myocardial action potential duration, which indicates the potential to prolong QT interval, for nine non-cardiac drugs that have been reported to produce QT prolongation in man. The drugs were: astemizole; terfenadine; erythromycin; sparfloxacin; cisapride; probucol; terodiline; risperidone and sertindole. 1. There were reports of the appropriate finding with in vitro methods for six of the drugs and with in vivo methods for seven of the drugs. No reports were found concerning the remaining drugs with each method. This indicates that both methods are effective and each method would have correctly identified the drugs in question as having the potential to prolong the QT interval in man in all cases for which studies were reported. 2. This suggests that, if properly conducted, either method alone is sufficient for the pre-clinical assessment of QT interval prolongation. This does not support the routine use of both methods before the administration of new drugs to man.     

The Dutch famine and schizophrenia spectrum disorders

In the Dutch Hunger Winter at the end of World War II a combination of circumstances created the conditions of a natural experiment. Unlike other famines, the Dutch famine struck at a precisely circumscribed time and place, and in a society able to document the timing and severity of the nutritional deprivation as well as the effects on fertility and health. Because the Dutch maintained comprehensive military and health records, it was possible to compare the incidence of neurodevelopmental disorders in adulthood for birth cohorts exposed versus those unexposed to prenatal famine. We have conducted several studies guided by the hypothesis that prenatal micronutrient deficiencies can cause neurodevelopmental schizophrenia or related personality disorders. In this paper we shall summarize our previous work and combine the outcome data of the different studies. Early prenatal famine was found to be specifically and robustly associated with each of three conditions: (1) congenital anomalies of the central nervous system, (2) schizophrenia, and (3) schizophrenia spectrum personality disorders. We found that the greatest increase in the risk of schizophrenia spectrum disorder- schizophrenia plus spectrum personality disorder- occurred among males born in the famine cities in December 1945 (relative risk = 2.7; 95% confidence interval = 1.5-5.1). Persons born in December 1945 were generally conceived at the absolute peak of the famine (March-April 1945). In the hope that the associations we have found may offer clues to the aetiology of schizophrenia, we are currently tracing and examining the cases of schizophrenia after prenatal exposure to famine.     

Short-chain fatty acids improve clinical, pathologic, and microbiologic features of experimental shigellosis

Because of the metabolic and antibacterial actions of short-chain fatty acids (SCFA), their roles in modifying the clinicopathologic features of shigellosis were evaluated in a rabbit model of shigellosis. Acute colitis was induced in adult rabbits by intracolonic administration of Shigella flexneri 2a. After 24 h, rabbits were given 6-h colonic infusions of SCFA (acetate, propionate, n-butyrate; 60:30:40 mM) or SCFA-free solution (control); groups of rabbits were killed in batches of 2 or 3 animals at 24, 48, 72, and 96 h after treatment, for histologic and bacteriologic assessment. SCFA significantly reduced fecal blood and mucus and improved clinical symptoms. Histologically, SCFA significantly (P<.01) reduced mucosal congestion, cellular infiltration, and necrotic changes. SCFA also significantly (P<.05) reduced the number of shigellae in the colon. No such improvements occurred in the control group. SCFA may be useful agents in improving clinicopathologic features of shigellosis and should be clinically evaluated.     

Effectiveness of inactivated influenza vaccine among nursing home residents during an influenza type A (H3N2) epidemic

We performed serological phenotyping of HLA antigens in 175 patients with rheumatoid arthritis (RA) with (n = 41) and without (n = 134) renal involvement (RI), and DNA typing of HLA class II alleles in 75 patients. Among the patients with RA, the frequency of serologically determined HLA-DR4 was found to be significantly increased (odds ratio: 1.8, confidence interval: 1.3-2.5, p = 2.4x10(-4)). In the patients without RI, the frequency of serological DR4 significantly increased (odds ratio: 2.2, confidence interval: 1.6-3.3, p = 2. 6x10(-5)). On the other hand, among the patients with RI, a serological determinant, DR15, did significantly increase (odds ratio: 2.7, confidence interval: 0.9-8.4, p = 1.2x10(-3)) in comparison to the controls. At the DNA level, we found that the association of Japanese RA patients with serological HLA-DR4 was based on that with a genotype of HLA-DRB1*0405 (odds ratio: 2.4, confidence interval: 1.5-4.0, p = 4.4x10(-4)) and also found an association of HLA-DRB1*1501 (odds ratio: 2.8, confidence interval: 1.2-6.6, p = 0.017) with RA patients having RI. Our results confirmed the association of HLA-DRB1*04 with RA over the ethnic barrier at the DNA level. Our results also suggested a distinct genetic effect of HLA-DRB1*1501 in the aspect of the susceptibility of RI in RA.     

Aminosulfhydryl and aminodisulfide compounds enhance binding of the glucocorticoid receptor complex to deoxyribonucleic acid-coated cellulose and to chromatin

In the presence of amine-containing sulfhydryl compounds, binding of heat-transformed cytosolic rat liver glucocorticoid receptor complex (GRC) to double-stranded calf thymus DNA-coated cellulose and to rat liver chromatin was enhanced up to 10-fold. These observations were made under conditions when a maximum of 8% of the total GRC bound to DNA in the absence of test compound. Compounds which did not contain both a sulfhydryl and amine group were inactive. Phosphorothioate derivatives of the active sulfhydryl compounds were also inactive. However, pretreatment of the phosphorothioate compounds with alkaline phosphatase restored activity. Upon centrifugation at 8800g, amine-containing disulfide compounds at millimolar concentrations caused considerable sedimentation of the GRC in the absence of DNA-coated cellulose or chromatin and no apparent increase in GRC binding to DNA or chromatin. Amine-containing disulfide compounds at micromolar concentrations did not cause heavy sedimentation of the GRC and enhanced binding of the GRC to DNA-coated cellulose up to 9.5-fold. Thus, diaminosulfhydryl compounds and the disulfide 1,18-diamino-6,13-diaza-9,10-dithiaoctadecane (WR 149,024) possess both the ability to restore and preserve the steroid binding capacity of the glucocorticoid receptor and to enhance binding of the GRC to DNA and chromatin.     

Intermolecular cleavage by UmuD-like enzymes: identification of residues required for cleavage and substrate specificity

The UmuD-like proteins are best characterized for their role in damage-induced SOS mutagenesis. An essential step in this process is the enzymatic self-processing of the UmuD-like proteins. This reaction is thought to occur either via an intramolecular or intermolecular self-cleavage mechanism. Here, we demonstrate that it can also occur via an heterologous intermolecular cleavage reaction. The Escherichia coli UmuD enzyme demonstrated the broadest substrate specificity, cleaving both E. coli and Salmonella typhimurium UmuD substrates in vivo. In comparison, the wild-type S. typhimurium UmuD (UmuDSt) and MucA enzymes catalyzed intermolecular self-cleavage, but did not facilitate heterologous cleavage. Heterologous cleavage by the UmuDSt enzyme was, however, observed with chimeric UmuD substrates that possess residues 30-55 of UmuDSt. We have further localized the residue predominantly responsible for UmuDSt-catalyzed heterologous cleavage to Ser50 in the substrate molecule. We hypothesize that changes at this residue affect the positioning of the cleavage site of a substrate molecule within the catalytic cleft of the UmuDSt enzyme by affecting the formation of a so-called UmuD "filament-dimer". This hypothesis is further supported by the observation that mutations known to disrupt an E. coli UmuD' filament dimer also block intermolecular UmuDEc cleavage.     

Proliferative index of human luteinized granulosa cells varies as a function of ovarian reserve

OBJECTIVE: We examined whether the proliferative index of luteinized granulosa cells, as determined by flow cytometry, varied as a function of a woman's ovarian reserve, as reserve, as reflected by follicular-phase day 3 serum follicle-stimulating hormone. STUDY DESIGN: This prospective cohort study consisted of 19 women of similar chronologic age preparing for in vitro fertilization-embryo who met specific day 3 serum follicle-stimulating hormone criteria. The "low follicle-stimulating hormone" group consisted of 11 women with day 3 serum follicle-stimulating hormone levels < or = 6 IU/L. The "high follicle-stimulating hormone" group consisted of eight women with day 3 serum follicle-stimulating hormone levels > or = 18 IU/L. A total of 56 preovulatory follicles containing > or = 10(4) luteinized granulosa cells were examined by flow cytometry. The low follicle-stimulating hormone group was compared with the high follicle-stimulating hormone group to examine proliferative index as a function of serum day 3 follicle-stimulating hormone levels. RESULTS: The low follicle-stimulating hormone group had a greater proliferative index (11.1% +/- 0.4%) than did the high follicle-stimulating hormone group (8.3% +/- 0.6%), p < 0.001). This study demonstrates that in spite of the same chronologic age, luteinized granulosa cells from preovulatory follicles of women with day 3 serum follicle-stimulating hormone levels > or = 18 IU/L have a 25% decreased proliferative index compared with luteinized granulosa cells from women with day 3 serum follicle-stimulating hormone levels < or = 6. CONCLUSIONS: This suggests that granulosa cell proliferation is influenced by ovarian reserve and may explain in part the more favorable response to ovulation induction protocols that younger women demonstrate compared with women of more advanced reproductive age.     

The Vector System for dynamic gait analysis

This article explores dynamic versus static biomechanics, quantitative versus qualitative data, and practical uses in a clinical setting for the Vector System of gait analysis. This system uses a video camera connected to a computer to analyze gait.     

Management of metatarsus adductovarus

A retrospective analysis of 795 patients treated for metatarsus adductovarus by a standardized outpatient approach by one of the authors (D.S.W.) from 1970 to 1983 was conducted to evaluate the efficacy of a straight metal bar and attached reverse last shoe protocol. Criteria for inclusion were developed excluding those milder cases in which spontaneous resolution was expected and indeed occurred. Nearly uniform excellent results were encountered, with a 99% likelihood of obtaining a fully corrected foot. Surgical intervention was deemed necessary in under 1% of cases seen. The authors also examined birth weights and rank in relation to metatarsus adductovarus. Those children with the deformity had a mean birth weight of 7.6 pounds, without statistical variance from normal average birth weights. We were unable to establish any statistical association with birth rank. In light of the results of this study, which compare favorably with serial casting, we recommend this approach as a more economical and less disruptive and cumbersome technique for parent, patient, and physician.