Expressive semantic deficit in the productive language of males with fragile X syndrome

Eleven males with fragile x syndrome [fra(X)] between the ages of 6 and 41, with an average communication age of 4 years 4 months and 11 normally developing 4 year old boys were administered a sentence completion task that assessed expressive semantic competence. The fra(X) males produced significantly more semantic errors than the normally developing 4 year children. Additionally, it was shown that sentences which could be correctly completed by a wider choice of words affected fra(X) males more than the nondisabled children. These 2 results suggest that the expressive semantic system is an area of specific deficit in fra(X) males.

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Non-steroid anti-inflammatory drug associated ulcer: epidemiology, causation and treatment

Epidemiological evidence consistently indicates that aspirin or non-aspirin non-steroidal anti-inflammatory drug use is associated with the occurrence of gastric ulceration, gastric and ulcer bleeding, and ulcer death. Evidence on duodenal ulcer occurrence conflicts, possibly because of differences in study populations. A wide range of mechanisms could explain the occurrence of non steroidal-induced damage. These include inhibition of bicarbonate secretion, effects on mucus formation, and vascular actions. Not all effects are dependent on cyclo-oxygenase inhibition. Short-term studies in humans provide indications of likely therapeutic effects, but cannot demonstrate clinical efficiency. Although anti-secretory drugs and prostaglandins can protect patients against the development of duodenal or gastric ulcers, but not both, there is no clinical evidence which bears upon the critical issue of protection against complications.

Transient ischemia attenuates neuronal afterdischarges induced in the absence of synaptic transmission

In vitro hippocampal slices were prepared from animals previously subjected to a 10-min period of transient forebrain ischemia. Electrophysiological responses were examined in the selectively vulnerable CA1 region in the presence of standard (2.0 mM) and reduced (0.2 mM) calcium concentrations. Synaptic responses evoked by orthodromic stimulation in standard calcium were intact following ischemia. In contrast, repetitive neuronal discharges, which are normally evoked by antidromic stimulation in the presence of low calcium concentrations, were attenuated or eliminated following ischemia. The possible contributions of presynaptic and postsynaptic mechanisms to post-ischemic hyperexcitability are discussed.

DNA mismatch repair in Xenopus egg extracts: repair efficiency and DNA repair synthesis for all single base-pair mismatches

Repair of all 12 single base-pair mismatches by Xenopus egg extracts was measured by a physical assay with a sequence containing four overlapping restriction sites. The heteroduplex substrates, derivatives of M13 phage DNA, differed in sequence at the mismatch position only and permitted measurement of repair to both strands. The efficiency of repair varied about 4-fold between the most and least effectively repaired mismatches. Repair was most active with C/A and T/C mismatches but the efficiency varied depending on the orientation of the mismatch. Mismatch-specific DNA repair synthesis was also observed but the extent of repair was not always predictive of the extent of synthesis, suggesting the presence of different repair systems or different modes of mismatch recognition.

Some restriction endonucleases tolerate single mismatches of the pyrimidine.purine type

DNAs from phage mutants M13mp18 and M13mp18/MP-1 were used to construct two closed circular heteroduplexes. One of them carried the sequence 5'-CCTGGG-3' 3'-GGGCCC-5' with a T.G mismatch at the position 6248. The other carried the sequence 5'-CCCGGG-3' 3'-GGACCC-5' with a C.A mismatch at the same position. Heteroduplexes were exposed to 7 restriction endonucleases having recognition sites within the sequence 5'-CCCGGG-3' 3'-GGGCCC-5' and to 1 restriction endonuclease having a recognition site within the sequence 5'-CCTGGG-3' 3'-GGACCC-5'. All tested enzymes cleaved at least one mismatch-containing sequence although with reduced efficiency. Smal and Xmal tolerated both mismatch-containing sequences. Aval, Hpall, Mspl, Ncil and Nsplll were able to tolerate only the T.G containing sequence, while BstNl was able to tolerate only the C.A containing sequence. It is inferred that the tolerance displayed by Smal and Xmal depends on the presence of either the original purines or the original pyrimidines in mismatches of both the T.G and C.A type and that all other tested enzymes require the presence of the original purines in mismaches of both types.

The language of children with spina bifida and hydrocephalus: meeting task demands and mastering syntax

Children with hydrocephalus are thought to exhibit deficiencies in their linguistic performance, including the production of numerous off-topic utterances and semantically immature responses to linguistically posed problems (e.g., questions, word definitions). The hydrocephalic children included in many previous studies, however, have been mentally retarded. We sought to determine whether these language problems also characterized intellectually average children with hydrocephalus. A second purpose was to evaluate the hypothesis that the language problems of hydrocephalic children occur predominantly on tasks with high cognitive or linguistic demands. A third purpose was to reexamine the claim that despite their semantic-pragmatic deficiencies, the syntax of hydrocephalic children is age appropriate. Our hydrocephalic subjects dealt with the semantic-pragmatic requirements of linguistically posed problems in an age-appropriate manner, and although their performance on these problems declined as task demands increased, the decline was no more than that seen for nondisabled age-matches. The hydrocephalic children did not differ significantly from nondisabled age-matches on measures of productive syntactic maturity.

Mismatch repair involving localized DNA synthesis in extracts of Xenopus eggs

Repair of heteroduplex DNA containing G.T or A.C mismatches or containing two tandem unpaired bases occurred in vitro with Xenopus egg extracts as detected by a physical assay. The repair was accompanied by a mismatch-stimulated and mismatch-localized DNA synthesis. Repaired molecules, separated from unrepaired molecules, showed a 20- to 100-fold increase in DNA synthesis in the region of the mismatch compared to regions distant from the mismatch. The remaining unrepaired heteroduplex DNA included molecules that also displayed mismatch-stimulated DNA synthesis in the mismatch-proximal regions. These may represent intermediates in the repair process. The patterns of DNA synthesis suggest that repair begins at some distance from the mismatch and that as much as 1 kilobase or more can be involved in the mismatch-stimulated synthesis.

Immunosuppressive drugs and corticosteroids in the treatment of rheumatoid arthritis

Rheumatoid arthritis is the most common form of severe inflammatory arthropathy affecting patients at a relatively early age. Although there are a number of drugs which significantly reduce pain and swelling, few alter the development of erosions and progression of joint destruction. A significant number of patients with rheumatoid arthritis develop this progressive disability and will require treatment with corticosteroids or immunosuppressive agents. In this article the use of immunosuppressive drugs and corticosteroids in the treatment of aggressive rheumatoid arthritis is reviewed. Controlled clinical trials have shown that a number of these drugs can play a significant role in reducing pain and swelling and might possibly alter the disease course in rheumatoid arthritis. Side effects of these agents, including the potential for oncogenesis, still pose major problems in their long term use. The risks and benefits of immunosuppressive and corticosteroid drug therapy must be balanced in each patient to whom they are prescribed and reviewed at frequent intervals.

Estrogen therapy arrests bone loss in elderly women

Although osteoporosis is an age-related disorder, the accelerated bone loss observed in postmenopausal women may be preventable with early diagnosis and adequate estrogen replacement. In a prospective study, we investigated the effect of oral estrogen replacement using conjugated estrogens (Premarin, 0.625 mg) or micronized 17 beta-estradiol (Estrace, 1 mg) versus no estrogen in sequential single-photon bone density measurements over 3-year intervals in 397 postmenopausal women. Estradiol, 1 mg, and conjugated estrogens, 0.625 mg, were equally effective in regarding bone loss. The rate of bone loss was about the same for estrogen users regardless of age (51 to 80 years) and was approximately one third that of nonusers. Among nonusers a uniform accelerated rate of bone loss of 2.5% per year was noted between 56 and 70 years old, whereas between the ages of 51 and 55 years and after age 70 years, the rate of bone loss was significantly less. Ever users over age 65 years showed continued protection from bone loss as long as estrogen therapy was continued. Previous estrogen users who stopped estrogen after age 65 years lost bone more rapidly than women of similar age who had never taken estrogen. Thus to prevent accelerated bone loss in postmenopausal women, we recommend early and continued hormone replacement for life. Estrogen nonusers should be monitored at regular intervals to minimize accelerated bone loss.

Thickening of infant feedings for therapy of gastroesophageal reflux

To assess the effect of thickening of feedings on gastroesophageal reflux and gastric emptying, 20 infants were examined with technetium scintigraphy and detailed behavioral observation after each of a pair of feedings, one with radiolabeled infant formula alone and the other with radiolabeled formula thickened with dry rice cereal. The thickened and unthickened meals were followed by similar amounts of scintigraphically demonstrated gastroesophageal reflux. However, the number of episodes of emesis (1.2 +/- 0.7 vs 3.9 +/- 0.9 per 90 minutes postprandial), the percent of gastric emptying at 30 minutes (17.8% +/- 2.7% vs 22.4% +/- 2.4%), the time spent crying (11.7 +/- 3.1 minutes vs 17.6 +/- 3.8 minutes per 90 minutes), and the total time spent awake (45.2 +/- 5.9 minutes vs 53.1 +/- 4.9 minutes per 90 minutes) were significantly less after the thickened feedings. Because thickening of infant feedings increases the caloric density, decreases emesis, decreases crying time, and increases sleep time in the postprandial period, it is likely to be beneficial in the treatment of infants with gastroesophageal reflux associated with failure to thrive.

Organophosphorus Intermediates. IX. The Cleavage of α,ω-Bisdiphenylphosphinoalkanes With Lithium. A 13P N.M.R. Study

The title phosphines, Ph2P(CH2).PPh2 (n = 2-5), react with lithium in tetrahydrofuran to give the corresponding 1, n-dilithio-1, n-di(phenylphosphines) directly with little or no intermediacy of the 1-lithio- 1-phenyl- n- diphenylphosphinoalkanes which can, however, be obtained by arylation of the diphosphides. Methylenebisdiphenylphosphine and 1,4-diphenyl-1,4-diphosphinane undergo exclusive phosphorus-alkyl carbon cleavage. The chemistry and 31P n.m.r. spectroscopy of the diphosphides are described and the mechanism of the cleavage reaction is discussed. Some cleavage reactions in liquid ammonia are described.

Hydroxymethyluracil DNA glycosylase in mammalian cells

An activity has been purified 350-fold from extracts of mouse plasmacytoma cells that forms 5-hydroxymethyluracil (alpha-hydroxythymine) and apyrimidinic sites with phage SPO1 DNA, which contains this base in place of thymine. This DNA glycosylase presumably functions to eliminate hydroxymethyluracil, a major thymine-derived DNA lesion produced by ionizing radiation and oxidative damage. The enzyme has no cofactor requirement and is active in EDTA. Neither intermediate formation nor hydrolysis of hydroxymethyl-deoxyuridine or hydroxymethyldeoxyuridine monophosphate was detected. The enzyme does not cleave apyrimidinic sites in DNA. It does release uracil from the uracil-containing DNA of phage PBS2, but this activity is less than 2% of the predominant uracil DNA glycosylase activity of the cell, which is separated by phosphocellulose chromatography. The major uracil DNA glycosylase does not release hydroxymethyluracil from SPO1 DNA. The hydroxymethyluracil glycosylase is also separated upon phosphocelluose chromatography from a thymine glycol DNA glycosylase activity that is accompanied by an apyrimidinic endonuclease activity.