Fibrosis assessment in patients with nonalcoholic fatty liver disease: Adherence to proposed algorithms and barriers to complying with them

INTRODUCTION AND AIMS

Fibrosis staging in patients with nonalcoholic fatty liver disease (NAFLD) is carried out through the application of stepwise algorithms but there is little real-world data on their use. Our aim was to calculate the number of patients with NAFLD and indeterminate or high risk for fibrosis, assessed through noninvasive scores, that consequently underwent further staging evaluation.

MATERIALS AND METHODS

A cross-sectional multicenter cohort study was conducted on patients with NAFLD evaluated by hepatologists within the time frame of June 1 and July 31, 2018. The FIB-4 and NAFLD fibrosis scores were calculated in all the patients, and if at least one of the scores suggested indeterminate or high risk for fibrosis, we believed the patient should have undergone additional fibrosis staging assessment.

RESULTS

The study included 238 patients. The median time interval from NAFLD diagnosis and inclusion in the analysis was 12.2 months (IQR 3.0-36.5). A total of 128 (54%) patients had at least one noninvasive score that suggested indeterminate or high risk for fibrosis but studies to confirm the fibrosis grade (elastography, biopsy, etc.) were performed on only 72 (56%). The main barriers encountered by the physicians for applying the staging algorithms were related to health insurance coverage and imaging study costs.

CONCLUSIONS

A high percentage of patients with NAFLD were at indeterminate or high risk for fibrosis, according to noninvasive scores, but additional studies were carried out on only half of them, showing low adherence to current recommendations.

Fibrosis assessment in patients with nonalcoholic fatty liver disease: Adherence to proposed algorithms and barriers to complying with them

INTRODUCTION AND AIMS

Fibrosis staging in patients with nonalcoholic fatty liver disease (NAFLD) is carried out through the application of stepwise algorithms but there is little real-world data on their use. Our aim was to calculate the number of patients with NAFLD and indeterminate or high risk for fibrosis, assessed through noninvasive scores, that consequently underwent further staging evaluation.

MATERIALS AND METHODS

A cross-sectional multicenter cohort study was conducted on patients with NAFLD evaluated by hepatologists within the time frame of June 1 and July 31, 2018. The FIB-4 and NAFLD fibrosis scores were calculated in all the patients, and if at least one of the scores suggested indeterminate or high risk for fibrosis, we believed the patient should have undergone additional fibrosis staging assessment.

RESULTS

The study included 238 patients. The median time interval from NAFLD diagnosis and inclusion in the analysis was 12.2months (IQR 3.0-36.5). A total of 128 (54%) patients had at least one noninvasive score that suggested indeterminate or high risk for fibrosis but studies to confirm the fibrosis grade (elastography, biopsy, etc.) were performed on only 72 (56%). The main barriers encountered by the physicians for applying the staging algorithms were related to health insurance coverage and imaging study costs.

CONCLUSIONS

A high percentage of patients with NAFLD were at indeterminate or high risk for fibrosis, according to noninvasive scores, but additional studies were carried out on only half of them, showing low adherence to current recommendations.

Evidence for multiple sylvatic transmission cycles during the 2016-2017 yellow fever virus outbreak, Brazil

OBJECTIVES

Since December 2016, Brazil has experienced an unusually large outbreak of yellow fever (YF). Whether urban transmission may contribute to the extent of the outbreak is unclear. The objective of this study was to characterize YF virus (YFV) genomes and to identify spatial patterns to determine the distribution and origin of YF cases in Minas Gerais, Espírito Santo and Rio de Janeiro, the most affected Brazilian states during the current YFV outbreak.

METHODS

We characterized near-complete YFV genomes from 14 human cases and two nonhuman primates (NHP), sampled from February to April 2017, retrieved epidemiologic data of cases and used a geographic information system to investigate the geospatial spread of YFV.

RESULTS

All YFV strains were closely related. On the basis of signature mutations, we identified two cocirculating YFV clusters. One was restricted to the hinterland of Espírito Santo state, and another formed a coastal cluster encompassing several hundred kilometers. Both clusters comprised strains from humans living in rural areas and NHP. Another NHP lineage clustered in a basal relationship. No signs of adaptation of YFV strains to human hosts were detected.

CONCLUSIONS

Our data suggest sylvatic transmission during the current outbreak. Additionally, cocirculation of two distinct YFV clades occurring in humans and NHP suggests the existence of multiple sylvatic transmission cycles. Increased detection of YFV might be facilitated by raised awareness for arbovirus-mediated disease after Zika and chikungunya virus outbreaks. Further surveillance is required, as reemergence of YFV from NHPs might continue and facilitate the appearance of urban transmission cycles.

Reduced work/academic performance and quality of life in patients with allergic rhinitis and impact of allergen immunotherapy

Background

Allergic rhinitis (AR) is characterised by burdensome nasal and/or ocular symptoms. This inflammatory disease can be debilitating and thus result in considerable health-related and economic consequences.

Methods

In a cross-sectional study, adult subjects with AR (N = 683) completed three allergy-specific questionnaires that assessed the impact of AR on the work/academic performance, daily activities, health-related quality of life (HRQOL), and satisfaction with allergen immunotherapy (AIT). Regression analyses were used to examine the associations between several clinical variables and the patient-reported outcomes.

Results

Total loss of productivity was 21.0 and 21.2 % for employed and student patients, respectively, whereas the impairment of daily activities was 22.0 %. The mean overall HRQOL score was 1.94 ± 1.29 (on the scale of 0–6 points). Global score for satisfaction with AIT was 65.5 ± 24.8 (on a 0–100 scale). Simple regression analysis found statistically significant associations between loss of work and academic productivity, impairment of daily activities and the type and severity of AR. AIT was a protective factor. The persistent and more severe types of AR and lack of AIT contributed to the worsening of HRQOL.

Conclusions

AR (the persistent and more severe form of the disease) has an impact on functional characteristics of adult patients in Spain. AIT might reduce the effect of this disease on the work/academic performance and HRQOL.

Trial registration Retrospectively registered

Aristolochic acid I metabolism in the isolated perfused rat kidney

Aristolochic acids are natural nitro-compounds found globally in the plant genus Aristolochia that have been implicated in the severe illness in humans termed aristolochic acid nephropathy (AAN). Aristolochic acids undergo nitroreduction, among other metabolic reactions, and active intermediates arise that are carcinogenic. Previous experiments with rats showed that aristolochic acid I (AA-I), after oral administration or injection, is subjected to detoxication reactions to give aristolochic acid Ia, aristolactam Ia, aristolactam I, and their glucuronide and sulfate conjugates that can be found in urine and feces. Results obtained with whole rats do not clearly define the role of liver and kidney in such metabolic transformation. In this study, in order to determine the specific role of the kidney on the renal disposition of AA-I and to study the biotransformations suffered by AA-I in this organ, isolated kidneys of rats were perfused with AA-I. AA-I and metabolite concentrations were determined in perfusates and urine using HPLC procedures. The isolated perfused rat kidney model showed that AA-I distributes rapidly and extensively in kidney tissues by uptake from the peritubular capillaries and the tubules. It was also established that the kidney is able to metabolize AA-I into aristolochic acid Ia, aristolochic acid Ia O-sulfate, aristolactam Ia, aristolactam I, and aristolactam Ia O-glucuronide. Rapid demethylation and sulfation of AA-I in the kidney generate aristolochic acid Ia and its sulfate conjugate that are voided to the urine. Reduction reactions to give the aristolactam metabolites occur to a slower rate. Renal clearances showed that filtered AA-I is reabsorbed at the tubules, whereas the metabolites are secreted. The unconjugated metabolites produced in the renal tissues are transported to both urine and perfusate, whereas the conjugated metabolites are almost exclusively secreted to the urine.

Polymorphisms of the promoter and exon 3 of the receptor for advanced glycation end products (RAGE) in Euro- and Afro-Brazilians

The receptor for advanced glycation end products (RAGE or AGER), a member of the immunoglobulin superfamily, is involved in pathologies such as atherosclerosis and diabetes. Over 50 SNPs were reported for RAGE, among which were the promoter region polymorphisms -429T>C (rs1800625), -374T>A (rs1800624) and a 63-bp deletion (-407 to -345 bp), all related to increased RAGE expression. Additionally, in the exon 3, a putative site of binding ligands, the missense variation G82S (rs2070600) was associated with skin disorders in patients with diabetes. We have determined allele, genotype and haplotype frequencies of RAGE polymorphisms -429T>C, -374T>A, 63-bp deletion and G82S in Euro-Brazilians (n = 108) and Afro-Brazilians (n = 91), characterized according to the predominant ancestry of the individuals. The allele frequencies for Euro- and Afro-Brazilians were as follows: -429C, 12.5% vs. 12.1% (P = 0.90); -374A, 31.5% vs. 26.2% (P = 0.25); 63del, 0.0% vs. 3.8% (P = 0.004); and 82S, 1.9% vs. 0.6% (P = 0.24). Absolute linkage disequilibrium was found between the promoter polymorphisms -429T>C and -374T>A plus the 63-bp deletion (D'=1.000; P < 0.0001). The haplotype frequencies differed (P = 0.003) between Euro- and Afro-Brazilians. Our results showed that the frequencies of the 63-bp deletion were higher in Afro-Brazilians, while the other analysed polymorphisms were similarly distributed in the studied populations. The -374T>A plus 63-bp deletion polymorphism captures more than 80% of the haplotypic variation in the studied population.

Single-acquisition method for simultaneous determination of extrinsic gamma-camera sensitivity and spatial resolution

A new method for measuring simultaneously both the extrinsic sensitivity and spatial resolution of a gamma-camera in a single planar acquisition was implemented. A dual-purpose phantom (SR phantom; sensitivity/resolution) was developed, tested and the results compared with other conventional methods used for separate determination of these two important image quality parameters. The SR phantom yielded reproducible and accurate results, allowing an immediate visual inspection of the spatial resolution as well as the quantitative determination of the contrast for six different spatial frequencies. It also proved to be useful in the estimation of the modulation transfer function (MTF) of the image formation collimator/detector system at six different frequencies and can be used to estimate the spatial resolution as function of the direction relative to the digital matrix of the detector.

Synthesis of the PhIP Adduct of 2‘-Deoxyguanosine and Its Incorporation into Oligomeric DNA

The 2'-deoxyguanosine adduct of the dietary mutagen 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) has been synthesized and incorporated into DNA using solid state synthesis technology. The key step to obtaining the C8-dG adduct is a palladium (Xantphos-chelated)-catalyzed N-arylation (Buchwald-Hartwig reaction) of PhIP by a suitably protected 8-bromo-2'-deoxyguanosine derivative. The reaction proceeded in good yield without complicating side products, and the adduct was converted to the required 5'-O-DMT-3'-O-phosphoramidite by standard methods. This modified deoxynucleoside was used to synthesize three oligodeoxynucleotides in which the C8-PhIP-dG adduct was incorporated at a single site. The oligomers were purified by reverse phase HPLC and characterized by mass spectrometry.

Incorporation of N2-deoxyguanosine metabolic adducts of 2-aminonaphthalene and 2-aminofluorene into oligomeric DNA

In previous work we described an efficient procedure for the synthesis of the respective N2 and N6 adducts of 2'-deoxyguanosine (dG) and 2'-deoxyadenosine (dA) derived from a series of aminoaryl compounds. We now outline methods for the site-specific introduction into oligomeric DNA of the adducts dG-N2-AN (6), dG-N2-AAN (7), dG-N2-AF (8), and dG-N2-AAF (9) derived from 2-aminonaphthalene (2-AN) or 2-aminofluorene (2-AF). For the 2-AN adduct 7, containing an acetylamino group, the 5'-O-4,4'-dimethoxytrityl- (DMT-) 3'-O-phosphoramidite (14) required for automated DNA synthesis was synthesized in high yield via the sequence 10-->11-->14. On the other hand, introduction of the desacetyl adduct 6 into oligomeric DNA was accomplished via the N-trifluoroacetyl-DMT-phosphoramidite derivative 18. This involved a similar sequence (10-->15-->18) except that the order of the reactions was changed to avoid a decomposition that occurred when the silyl-protected amino derivative 11 was treated with trifluoroacetic anhydride. In the 2-AF series the 5'-O-DMT-3'-O-phosphoramidites 27a and 27b, related to 8 and 9, were prepared by similar methods. Again, however, the order of the reactions was changed to avoid the extreme insolubility associated with the N2-[3-(2-acetylaminofluoren-3-yl)]dG (dG-N2-AAF, 9) adduct that we had noted previously. The incorporation into oligomeric DNA of the acetylamino compounds 7 and 9 proceeded smoothly and in high yield (95-100%). By contrast, the trifluoroacetyl analogues led in both the naphthyl and fluorenyl series to a mixture of oligomers containing the desired free amino adduct (6 or 8) accompanied by the N-acetyl adduct (7 or 9, respectively, after the deprotection step), indicating secondary acetylation by the capping agent acetic anhydride.

Acrylates induced rhinitis and contact dermatitis

Acrylates are a well-known cause of occupational contact dermatitis due to its widespread use in several settings such as dentistry, orthopaedic surgery, graphic industry and cosmetics. We describe the case of a manicurist who developed occupational rhinitis and allergic contact dermatitis induced by the application of acrylic-sculptured nails.

Stereoselective excision of thymine glycol from oxidatively damaged DNA

DNA damage created by reactive oxygen species includes the prototypic oxidized pyrimidine, thymine glycol (Tg), which exists in oxidatively damaged DNA as two diastereoisomeric pairs. In Escherichia coli, Saccharomyces cerevesiae and mice, Tg is preferentially excised by endonuclease III (Endo III) and endonuclease VIII (Endo VIII), yNTG1 and yNTG2, and mNTH and mNEIL1, respectively. We have explored the ability of these DNA glycosylases to discriminate between Tg stereoisomers. Oligonucleotides containing a single, chromatographically pure (5S,6R) or (5R,6S) stereoisomer of Tg were prepared by oxidation with osmium tetroxide. Steady-state kinetic analyses of the excision process revealed that Endo III, Endo VIII, yNTG1, mNTH and mNEIL1, but not yNTG2, excise Tg isomers from DNA in a stereoselective manner, as reflected in the parameter of catalytic efficiency (kcat/Km). When DNA glycosylases occur as complementary pairs, failure of one or both enzymes to excise their cognate Tg stereoisomer from oxidatively damaged DNA could have deleterious consequences for the cell.

Regioselective synthesis of 1,N(2)-etheno-2'-deoxyguanosine and its generation in oligomeric DNA

Chloroethylene oxide and chloroacetaldehyde, reactive intermediates derived from vinyl chloride, and the epoxy-hydroxy-alkanals, produced endogenously in the metabolism of polyunsaturated fatty acids, react with nucleic acid bases in DNA to form exocyclic etheno derivatives of 2'-deoxyadenosine, 2'-deoxyguanosine, and 2'-deoxycytidine. This paper describes an efficient method for the synthesis of the exocyclic 1,N(2)-etheno adduct of 2'-deoxyguanosine and its incorporation into DNA oligomers using automated synthesis techniques. The synthesis was initiated by a high-yield alkylation of N(2)-protected 2'-deoxyguanosine at the 1-position with 1,2-diacetoxy-3-bromopropane. The product was converted to the 5'-O-dimethoxytrityl-3'-O-phosphoramidite using published techniques and incorporated site specifically into DNA oligomers with 99% coupling efficiency. Ring closure to yield the 6-hydroxyethano derivative was accomplished by oxidation with sodium periodate, and facile dehydration then afforded DNA oligomers containing 1,N(2)-etheno-2'-deoxyguanosine. All oligomers were characterized fully by physicochemical methods.

Synthesis of the minor acrolein adducts of 2(')-deoxyguanosine and their generation in oligomeric DNA

Acrolein, a known mutagen, undergoes reaction in vitro under physiological conditions with both 2(')-deoxyguanosine and native DNA to give rise to exocyclic adducts of the 5,6,7,8-tetrahydropyrimido[1,2-a]purine-10(3H)-one class having an hydroxy group at either the 6 or the 8 position. Previously we have shown that the 8-hydroxy derivative in a bacterial system has very low mutagenicity probably because in double-stranded DNA this residue exists in the open-chain aldehydic form [N(2)-(3-oxopropyl)-2(')-deoxyguanosine] (3). To continue our investigation in this area, we needed ample supplies of the 6-hydroxy isomers. This current paper describes high-yield simple methods for the synthesis in bulk of the 6-hydroxy adduct 1 and its incorporation into DNA oligomers. The basic methods for the synthesis of the adduct 1, involve 1-substitution of dG derivatives with a 3-butenyl group, dihydroxylation of the olefin with osmium tetroxide and N-methylmorpholine N-oxide, then diol cleavage with periodate ion after incorporation of the 1-(3,4-diacetoxybutyl)-2(')-deoxyguanosine into oligomeric DNA.

Efficient synthesis of the benzo[a]pyrene metabolic adducts of 2'-deoxyguanosine and 2'-deoxyadenosine and their direct incorporation into DNA

A new and efficient method is described for the synthesis in gram quantities of the benzo[a]pyrene (B[a]P) metabolic adducts of 2'-deoxyguanosine (dG) and 2'-deoxyadenosine (dA) substituted, respectively, at the N(2)- and N(6)- positions. When the racemic form of the tris(benzoyloxy)amine 5 (related to the notoriously carcinogenic epoxydiol 2) is coupled with the bromoinosine derivative 6 by means of a Buchwald-Hartwig reaction, the expected pair of diastereomers, 7 and 8, is obtained in high (combined) yield. Selective deblocking of this mixture then gave cleanly the pair of diastereomers 9. These were used in the synthesis of a series of DNA oligomers via their 5'-O-DMT-3'-O-phosphoramidites (10) using standard automated methods. Coupling efficiencies were 94-98% at the point of introduction of the xeno-2'-deoxynucleoside, and in all cases the mixtures of the two diastereomeric oligomers (DMT-off stage) were easily separated by HPLC. By a similar sequence of reactions beginning with 5 and the protected 6-bromopurine 2'-deoxynucleoside 11, it was possible with equal efficiency to introduce the N(6)-modified diastereomers (16) of dA into oligomeric DNA. Circular dichroism measurements were used to establish the fundamental configurations at the xeno-2'-deoxynucleoside site for each of the oligomers. Mass spectral data in both the dG and the dA series confirmed the presence of the xeno-2'-deoxynucleoside in the oligomers. This was complemented by enzymatic degradation of one of the oligomers from each of the series. In both of these cases, after HPLC separation, circular dichroism measurements on the reisolated xenonucleoside also confirmed its presence in the oligomer.

Salivary Streptococcus mutans and Lactobacillus sp levels in cardiac children

This study assesses salivary conditions of 20 children with cardiac disease comparing with a control group of 15 healthy children. The results showed that there was no difference between the groups on salivary flow, buffer capacity and the level of Streptococcus mutans (Sm). The test group i.e., children with cardiac disease, showed a lower level of Lactobacillus sp. The association between the usage of antibiotics and the risk of developing caries, measuring the level of Streptococcus mutans and Lactobacillus sp., showed that children taking antibiotics frequently had a significant lower level of Lactobacillus sp (p<0.05) than healthy children. This association was not found on relation to the levels of Streptococcus mutans.

Development of a child with Joubert syndrome

The article describes the development of a child with Joubert Syndrome who, since the age of 16 months, has received personalized stimulation therapy at home and in the Early Intervention Unit (EIU) of the Faculty, in each of the five areas considered by the Portage Guide to Early Education: socialization, language, self-help, cognition, and motoricity. Repeated evaluations during the treatment (up to age 40 months) showed show progress in all developmental areas, as well as in general attitude to and capacity for learning. During treatment, greatest progress was made in the areas of cognition and communication.

Molecular epidemiologic analysis of Mycobacterium bovis isolates from Mexico

OBJECTIVE

To assess phylogenetic relationships among Mycobacterium bovis isolates by use of random amplified polymorphic DNA polymerase chain reaction (RAPD-PCR) fingerprinting and to relate genetic profiles of isolates to epidemiologic characteristics.

ANIMALS

400 cattle with tuberculosis.

PROCEDURE

Mycobacterium bovis was isolated from various organs of cattle slaughtered in 6 geographic regions of Mexico. Most cattle were adult Holsteins from large herds that did not participate in a tuberculosis control program. Four random primers and 2 selected primers were used in RAPD-PCR fingerprinting of 88 isolates. Pairwise genetic distance between isolates was obtained and subjected to cluster analysis with bootstrapping to test for levels of support.

RESULTS

98 different fragments were obtained; there was broad genetic diversity among isolates, and each isolate had a unique RAPD-genotype, including those originating from the same herd. Clustering by geographic location, affected organ, or severity of lesion was not detected. Linkage disequilibrium analysis suggested that M. bovis was highly clonal and that mutations develop at a rapid rate among isolates.

CONCLUSIONS AND CLINICAL RELEVANCE

Use of RAPD-PCR could not differentiate M. bovis isolates by epidemiologic characteristics or identify common sources of infection.

Formation of s-triazines during aerial oxidation of 8-oxo-7,8-dihydro-2'-deoxyguanosine in concentrated ammonia

After automated DNA synthesis, oligodeoxynucleotides containing 8-oxoguanine are sensitive to aerial oxidation when subjected to the basic conditions necessary for deprotection and release of the oligomer from the control pore glass support. The major oxidation products of this heterocyclic moiety have been characterized by permitting 8-oxo-7,8-dihydro-2'-deoxyguanosine to react with oxygen in the presence of 28% aqueous ammonia at room temperature. Products were isolated by reverse phase HPLC and analyzed by electrospray ionization-mass spectrometry and gas chromatography-mass spectrometry of the trimethylsilyl-derivatives. 2-Amino-4-hydroxy-s-triazine-6-carboxylic acid and 2-amino-4-hydroxy-6-carbamyl-s-triazine were identified by these techniques and standards were synthesized. In addition, GC-MS analysis revealed other oxidation products, including urea, guanidine and 2-deoxyribose, which were not observed by HPLC because these compounds are transparent in the UV region of the spectrum. Both s-triazines were also observed when a purified, synthetic oligodeoxynucleotide containing a single 8-oxoguanine moiety was exposed to the same conditions. Oxidation of 8-oxoguanine appears to parallel the uric acid oxidation pathway, and a mechanistic scheme is proposed to account for the products of degradation.

The relationship between life-events and periodontitis. A case-control study

This case-control study (n = 100 dental patients, matched for age and sex) investigated the role of life-events in periodontitis. Data collected included life events, tobacco use, oral health behaviours and socio-demographics. The results of conditional simple logistic regression analysis showed that periodontitis was associated with the negative impact of life-events (p < 0.01), the number of negative life-events (p < 0.05), high levels of dental plaque (p < 0.01), tobacco smoking (p < 0.01) and being unemployed (p < 0.05). These associations remained statistically significant after adjusting for oral health behaviour and socio-demographic variables, but not tobacco smoking (p > 0.05). Marital status became statistically significant after adjusting for the other variables (p < 0.05). A model is suggested to explain the pathways through which life events may affect periodontal health. It was concluded that psychosocial factors and oral health risk behaviours cluster together as important determinants of periodontitis.

Characterization of the alkaline degradation products of an oligodeoxynucleotide containing 8-oxo-7,8-dihydro-2'-deoxyguanosine by electrospray ionization mass spectrometry

Oligodeoxynucleotides containing 8-oxo-7,8-dihydro-2'-deoxyguanosine exhibit alkaline sensitivity and undergo cleavage of the phosphodiester backbone. Identification of the major degradation products and unstable intermediates formed in concentrated ammonia was accomplished by HPLC isolation and characterization by electrospray ionization mass spectrometry. Unstable intermediates were reduced in situ with NaBH4 prior to isolation and mass analysis. This technique produced accurate mass data for an oligonucleotide intermediate containing an abasic site, a strand cleavage, product containing the 3'-terminus, and two products with the 5'-terminus. 8-Oxoguanine was not present in the product HPLC chromatogram, suggesting rearrangement or degradation of this moiety prior to glycosidic bond cleavage. A scheme for the decomposition of 7,8-dihydro-2'-deoxyguanosine-containing oligonucleotides in 28% ammonia solution is presented.

Analysis of synthetic oligodeoxynucleotides containing modified components by electrospray ionization mass spectrometry

Electrospray ionization mass spectrometry (ESI/MS) has been used to confirm the synthesis of oligodeoxynucleotides containing modified structures and to identify products of unstable oligomer degradation. Negative ion mass spectra of oligomers and dimethoxytrityl-protected oligomers exhibited a distribution of multiply charged molecular ions with few adduct ions present. Molecular masses may be determined from the array of peaks with excellent accuracy and serve to corroborate the synthetic sequence and the inclusion of a modified structure within the sequence. Incorporation of modified deoxynucleotides, stable isotopes, and other novel structures such as a terminal biotin moiety and a phosphorothioate linkage can be rapidly verified by ESI/MS. This technique has also proved useful for the identification of products of unstable oligomers formed during synthesis, deprotection, or purification, including the major products formed under basic conditions from 5'-dimethoxytrityl-protected oligomers containing 8-oxo-2'-deoxyguanosine.

Effect of diazepam on successive negative contrast in one-way avoidance learning

The effect of administration of diazepam on successive negative contrast in one-way avoidance learning was examined in rats. Contrast was induced by shifting rats from a large reward, 30 s spent in the safe compartment, to a small reward, 1 s spent in the safe compartment. IP administration of 2 mg/kg diazepam eliminated this negative contrast. Moreover, this effect is dose dependent, with doses of 2 and 2.5 mg/kg, but not 0.5 mg/kg, effective in reliably reducing contrast. These results suggest the existence of similar or common underlying mechanisms in both aversive and appetitive contrast effects; they are discussed in light of the current theories of frustrative nonreward and as a mean of studying the behavioral and biological mechanisms of anxiety.

Startle disease, or hyperekplexia: Response to clonazepam and assignment of the gene (STHE) to chromosome 5q by linkage analysis

Familial startle disease (also known as hyperekplexia and congenital "stiff-man" syndrome) is an autosomal dominant disorder characterized by an exaggerated startle reaction of sudden, unexpected auditory or tactile stimuli; affected neonates also have severe and occasionally fatal hypertonia. We recently encountered a large, five-generation family with startle disease, and treated 16 patients (including 1 neonate) with clonazepam; all experienced dramatic and sustained improvement. We performed systematic linkage analysis in this family, and found tight linkage between the disease locus and a polymorphic genetic marker locus (colony-stimulating factor receptor, or CSF1R) that has been physically mapped to chromosome 5q33-q35. The maximum odds ratio favoring linkage over nonlinkage is greater than 10,000,000:1 (lod score, 7.10) at 3% recombination. Several genes encoding neurotransmitter receptor components have been physically mapped to the subtelomeric region of chromosome 5q, and are thus candidates for the startle disease gene. The availability of additional large pedigrees with startle disease should facilitate identification and characterization of the gene for this disorder.

Benign familial neonatal convulsions: evidence for clinical and genetic heterogeneity

The gene for autosomal dominant "benign" familial neonatal convulsions, a transient, primary epilepsy of infancy, has recently been assigned to chromosome 20q. To determine whether this disorder is genetically heterogeneous, we performed linkage analysis in two previously unreported pedigrees with benign familial neonatal convulsions in which clinical heterogeneity was evident. There were 14 affected persons in the first family, and none had seizures (febrile or afebrile) after the age of 2 months. The second family had 13 affected individuals and 2 obligate carriers; seizures frequently did not remit until 6 to 24 months, febrile convulsions occurred in at least 2 patients, apparent audiogenic seizures occurred in 4 patients, and 1 individual had refractory epilepsy until late adolescence. Linkage studies with the chromosome 20 markers D20S19 and D20S20 were performed in both families. The resulting data favored linkage of the disease and marker loci in Family 2 by a maximum odds ratio of 45:1 at 6% recombination. In Family 1, however, the odds were greater than 20,000:1 against linkage at 10% recombination or less. We conclude that the syndrome of benign familial neonatal convulsions is clinically and genetically heterogeneous. Further study will be necessary to clarify the relationship between phenotype and genotype in this disorder.

A model for a health career information center

A model health career information center was developed and evaluated at a university health science center. One part of the information center is a statewide, toll-free health careers hotline which provides information about health careers to high school and college students, parents, counselors, and teachers, especially in small schools and rural areas, which are not usually included in recruiting circuits. Evaluation of the hotline after one year of operation has indicated that it fills a need, is considered useful by callers, and is of a relatively small cost, considering the geographical coverage. The model information system proposed can be implemented in phases with only slight modifications to meet the unique needs of specific health science centers or their geographical location.