Male Fischer344 rats were exposed to x-irradiation at a dose of 200 rad on Day 17 of gestation. Irradiated and control rats were tested at 10-13 weeks of age with the paradigm of go/no-go (active-passive) discriminated avoidance conditioning for three consecutive daily sessions. During the first conditioning session, they learned only active avoidance responses to two different warning signals. During the second and third sessions, they learned active and passive avoidance responses: in response to one warning signal, rats were required to make an active response to avoid a shock, but not to run in response to the other signal in order to avoid a shock. Prenatally irradiated rats made more active avoidance responses to both warning signals than controls (first session). In the early training phase of the go/no-go task, irradiated rats performed significantly higher active and lower passive avoidance responses than controls. Irradiated rats established a strong tendency to respond actively to the no-go signal, but eventually learned to respond to it.

Animals↗

PubMedDate not supplied

Effect of mic gene structure on repressor activity in the OmpA system.

It has been previously established that micRNA (mRNA-interfering complementary RNA) complementary to an individual mRNA specifically represses the expression of the target mRNA. We have constructed several plasmids which produce micRNAs which are complementary to different regions of the ompA mRNA. The repressor activity of these different micRNAs has been compared to determine the role of mic gene structure in effective micRNA function. The results indicate that micRNAs complementary to regions of the ompA mRNA likely to encounter ribosomes have the highest repressor activities. A clear effect of mic gene dosage was also observed. This was demonstrated using both identical and different mic(ompA) genes.

Bacterial Outer Membrane Proteins↗

PubMedDate not supplied

A novel immune system against bacteriophage infection using complementary RNA (micRNA).

The "operon' theory of gene regulation, in which protein repressor molecules bind to the operator site of a gene to prevent its transcription, is now well established. Recently, however, cases have been discovered in which gene expression is regulated by complementary RNA molecules that are able to bind to the transcripts of particular genes and consequently prevent their translation. For example, the synthesis of OmpF protein (a major outer membrane protein) in Escherichia coli is regulated by a short RNA complementary to a region of ompF RNA encompassing the "Shine-Dalgarno' sequence and the translation initiation codon. This RNA has been termed micRNA (messenger-RNA-interfering complementary RNA), and its discovery has prompted us to construct an artificial micRNA system designed to regulate gene expression in E. coli. A given target gene can be repressed by artificially producing an RNA (micRNA) complementary to the mRNA encoded by that gene. A micRNA system has also been used successfully in tissue-cultured mammalian cells. The use of artificial micRNAs to specifically regulate individual genes has great potential as a novel cellular immune system for blocking bacteriophage or virus infection. Here, we report that on induction of micRNAs directed against the coat protein and/or the replicase of the E. coli bacteriophage SP, phage proliferation was effectively prevented. We propose that the micRNA immune system provides an effective means of preventing viral infection as well as the expression of harmful genes in both prokaryotes and eukaryotes.

Base Sequence↗

PubMedDate not supplied

Prediction of functional outcome after stroke rehabilitation.

OBJECTIVE: The purpose of this study is to identify predictors of functional outcome after acute stroke inpatient rehabilitation using raw Functional Independence Measure (FIM) total scores. DESIGN: Multivariate analysis was performed on data collected retrospectively from stroke rehabilitation patients. Six independent variables were obtained from patients' medical records. RESULTS: The FIM total scores at the time of discharge from the hospital correlated strongly with FIM total scores at the time of admission to the hospital and correlated negatively with age and OAI using the Spearman's rank correlation method. The FIM total scores at the time of hospital admission were the best predictor of FIM total scores at the time of discharge from the hospital. However, the nature of the stroke, gender, and LOHS did not correlate with FIM total scores at the time of discharge from the hospital. CONCLUSIONS: Because FIM total scores at the time of hospital admission and discharge are highly correlated, FIM total scores at the time of hospital admission can be used to establish a rehabilitation program, to inform the patient and family about the possibility of recovery, and to assess the amount and quality of care given in the home or discharge placement.

Activities of Daily Living↗

PubMedDate not supplied

The effect of probucol on oxidized cholesterol disposition in hyperlipidaemic patients.

Probucol is a cholesterol-lowering and antioxidant drug that has been shown to inhibit or delay the progression of atherosclerosis. This antiatherosclerotic effect may result from the removal of oxidized cholesterol on the surface of low-density lipoprotein (LDL). To investigate whether probucol transfers oxidized cholesterol from LDL to urine, urine samples were obtained from five patients with hypercholesterolaemia treated with 500-mg probucol orally daily and from five healthy controls. Using gas chromatography-mass spectrometry, we identified cholesteryl-6-(2,6-di-tertiary butylphenol-4)-thioether (CT) in the urine samples from patients with hypercholesterolaemia but not from healthy controls. This result suggests that probucol is hydrolysed to form 4-mercapto-2,6-di-tertiary butylphenol (MBP) which conjugates with cholesterol-5 alpha, 6 alpha-epoxide, oxidized cholesterol, resulting in the formation of CT in vivo. In addition to its hypolipidaemic and antioxidant actions, probucol may act to prevent atherosclerosis by increasing the urinary excretion of oxidized cholesterol.

Anticholesteremic Agents↗

PubMedDate not supplied

Metabolism of o,p'-DDD in humans: a novel metabolic pathway forming methylthio-containing metabolites.

Urine samples were obtained from four patients with Cushing's syndrome who had been treated with o,p'-DDD[2,2-(2-chlorophenyl,4'-chlorophenyl)1,1-dichloroethane]. Methylthio-containing (MC) metabolites and other metabolites of o,p'-DDD were detected in the urine samples by gas chromatographic mass spectrometry. These MC metabolites showed smaller peaks in the gas chromatogram than other peaks derived from other metabolites of o,p'-DDD. Although the biological significance of the pathway forming these MC metabolites is not known at present, the mechanism of the metabolic pathway was discussed.

Cushing Syndrome↗

PubMedDate not supplied

Synthesis of the pro-peptide of subtilisin BPN'.

Subtilisin, a bacterial serine protease, is secreted as pre-pro-subtilisin. Previously, we demonstrated that the pro-peptide moiety of intact pro-subtilisin can guide the folding of inactive protein to active enzyme both in an intramolecular (6) and intermolecular manner (18). Herein is reported the total chemical synthesis of the pro-sequence (77 amino acids) of pre-pro-subtilisin BPN' carried out by solid phase methods. The structure was confirmed by both sequencing and amino acid analysis of the fragment peptides resulting from a V-8 protease digest. Preliminary studies indicate that the synthetic pro-peptide itself can renature denatured subtilisin BPN'. This study demonstrates a novel method for examining protein folding with the aid of exogenously added synthetic peptides.

Amino Acid Sequence↗

PubMedDate not supplied

Behavioral and neuropathological effects of prenatal methylmercury exposure in mice.

Pregnant C3H/HeN mice were orally administered a single dose of 20 mg/kg methylmercuric chloride on one of days 13 through 17 of pregnancy. They were allowed to give birth and the newborn mice were foster mothered, but the weaning rate was low. Long-term behavioral impairment was manifest in mice of every treated group. The righting movement was mildly disturbed when animals were dropped from about 40 cm high. The tail position was low during walking. Some animals showed strong flexion of the hind limbs when held by the tail. Spontaneous locomotor activity was reduced. At 10-12 weeks of age, the animals were sacrificed and the brain was histologically examined. The brain weight was reduced. The nucleus caudatus putamen was slightly reduced in size leaving the lateral ventricles dilated. Cerebellar folial patterns were slightly simplified. These neurobehavioral symptoms and pathological changes tended to be comparatively more severe in animals treated on days 13 and 14 of pregnancy than those of the other groups, but the differences were small.

Aging↗

PubMedDate not supplied

Function of the signal peptides in protein secretion across the membrane.

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Bacterial Proteins↗