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PubMed1975

Dietary tryptophan and the selection of ethyl alcohol in different strains of rats.

Rats of three different strains were tested systematically for their selection of water or ethanol offered in a two-choice situation. In order that preference-aversion curves could be derived, the concentrations of ethanol were increased in strength from 3 to 30% over an 11 or 12 day test sequence. L-tryptophan was added to the rat's diet in 1% or 3% mixtures for a predetermined interval beginning before or during a test for ethanol preference. Given to female hooded rats of the Royal Victoria strain, excess tryptophan elevated the ethanol preference threshold and significantly increased ethanol intake according to the dose administered. However, in male hooded rats of the Long-Evans strain, tryptophan augmented only slightly the selection of ethanol. Male Sprague-Dawley rats, an albino strain, were unaffected by the addition of this essential amino acid to their diet. Although tryptophan may exert its effect on ethanol intake through an alteration in the metabolism of cerebral serotonin, such an effect seems to be dependent upon the strain of rat tested.

5-Hydroxytryptophan↗
PubMed1984

Separation of sequences defining basal expression from those conferring alpha gene recognition within the regulatory domains of herpes simplex virus 1 alpha genes.

The genes of herpes simplex virus 1 form three major groups--alpha, beta, and gamma--whose expression is coordinately regulated and sequentially ordered in a cascade fashion. To determine how the infected cell differentiates between these gene groups, alpha-regulated chimeric genes were constructed in earlier studies by fusing the structural sequences of the thymidine kinase (TK) gene, a beta gene, to the 5' noncoding sequences of alpha genes. These studies showed that (i) one or more structural components of the virion act in trans to increase alpha gene expression and (ii) the 5' noncoding sequences of alpha genes contain cis-acting domains that promote gene expression and confer alpha-gene regulation. These two domains could be moved independently, but the regulatory domain required a promoter for its function. We report here the properties of three sequences containing features common to the regulatory regions of all alpha genes. Sequence 1, containing (G + C)-rich inverted repeats, increased the basal level of TK expression when fused 5' to either the alpha gene 4 promoter or the truncated beta TK promoter. The effect was to some extent orientation dependent. Moreover, sequence 1 restored beta regulation to the truncated beta TK promoter but did not confer alpha-specific regulation on any of the chimeric genes tested. Sequences 2 (49 base pairs) and 3 (29 base pairs), containing an (A + T)-rich homolog from alpha gene 27 and alpha gene 0, respectively, restored alpha-specific regulation to the alpha promoter gene but only sequence 2 conferred alpha regulation on the truncated beta promoter gene. Our results indicate that (i) in natural beta TK the promoter and regulatory domains overlap, (ii) sequence 1 determines basal level of expression and substitutes for a promoter component that is essential for beta but not alpha regulation, and (iii) conversion of a gene with a promoter into an alpha gene requires two elements. Sequence 2 may contain both whereas sequence 3 contains only one.

Amino Acid Sequence↗
PubMed1991

Structure prediction and modelling.

Protein structure prediction from sequence remains a major goal in molecular biology. The methods described in this review concentrate on deriving structural information through the detection of similarities between a test sequence and a database of known structures. Such methods are often referred to as knowledge-based strategies reflecting the use of a structural database in the analyses. The past year has seen considerable advances in both the development of automated procedures and their application to protein sequences of outstanding biological interest.

Algorithms↗
PubMed1990

The pyrimidine/purine-biased region of the epidermal growth factor receptor gene is sensitive to S1 nuclease and may form an intramolecular triplex.

The pyrimidine/purine-biased region located upstream of the EGF (epidermal growth factor) receptor gene transcription initiation sites was sensitive to S1 nuclease when under superhelical tension. The structural basis of this specific reactivity to S1 nuclease was probed by the use of diethyl pyrocarbonate. The patterns of modification suggested that the H-form proposed by Mirkin, Lyamichev, Drushlyak, Dobrynin, Filippov & Frank-Kamenetskii [Nature (London) (1987) 330, 495-497], which includes an intramolecular triplex and a single-stranded region, was the most plausible model for the sequence tested. The results of dimethyl sulphate modification also supported this model.

Base Sequence↗
PubMed1992

Transcriptional regulation by triiodothyronine requires synergistic action of the thyroid receptor with another trans-acting factor.

Human placental lactogen B (hCS-B) promoter activity is strongly stimulated by triiodothyronine (T3) in pituitary GC cells through interaction between the thyroid receptor and a thyroid receptor-binding element (TBE) spanning coordinates -67 to -41. This TBE is adjacent to the binding site for pituitary factor GHF1 (-95 to -68) which seems necessary for T3 stimulation of hCS-B promoter activity (M. L. Voz, B. Peers, A. Belayew, and J. A. Martial, J. Biol. Chem. 266:13397-13404, 1991). We here demonstrate actual synergy between the thyroid receptor and GHF1. Indeed, in placental JEG-3 cells devoid of factor GHF1, hCS promoter activity is barely stimulated by T3, while a strong response is observed in pituitary GC cells. In the latter, furthermore, neither the TBE nor the GHF1-binding site alone is sufficient to render the thymidine kinase promoter responsive to T3, while in combination they promote strong T3 stimulation. Close proximity between these sites is required for optimal synergy: T3 stimulation globally decreases with increased spacing. Furthermore, synergy occurs not only with a GHF1-binding site but also with all other factor recognition sequences tested (Sp1, NF1, CP1, Oct1, and CACCC boxes) and even with two other copies of the TBE. Nor is it specific to hCS TBE, since the palindromic sequence TCAGGTCA TGACCTGA (TREpal) also exhibits cooperativity.

Animals↗
PubMed1991

Systematic fractionation of serum antibodies using multiple antigen homologous peptides as affinity ligands.

The fractionation of polyclonal antibodies on multiple peptide ligands is described. The method is an application of a procedure for the synthesis of large numbers of peptides on individual polyethylene pins (Geysen et al., 1987). In this application, each pin-bound peptide is used as an affinity support. Antibodies bound to the peptides are then eluted, using buffers of either high or low pH. Each eluted antibody is then tested for specific binding to peptides or proteins, using ELISA procedures. A rabbit antiserum raised to gonococcal pilin was fractionated on a complete set of octapeptides homologous with the sequence of the pilin protein. Antibodies eluted from some of the peptides bound to pilin in solution. In a second example three hyperimmune sera raised to three different potyviruses were fractionated on their respective homologous peptide sequences. Testing the eluted antibodies on the three virus coat proteins revealed peptides which bound cross-reacting antibodies. Thus the method can be used to confirm direct peptide binding evidence for sequential epitopes. These peptides can then be used in affinity chromatography to increase the specificity of polyclonal sera. This can be achieved either by elution of the specific antibody from the peptide or by removal of cross-reacting antibodies from the whole serum by absorption on peptide.

Amino Acid Sequence↗
PubMed1987

Position-dependent sequence elements downstream of AAUAAA are required for efficient rabbit beta-globin mRNA 3' end formation.

We previously demonstrated that a critical 35 bp region 3' of the AAUAAA is required for rabbit beta-globin mRNA 3' end formation. Recently, we synthesized and tested sequence elements derived from this region. Here, we report that a GU-rich and a U-rich sequence element are both required for efficient rabbit beta-globin mRNA 3' end formation. The efficiency of processing is restored to the wild-type level when the two elements are placed together and is greatly diminished when only one element is present. The level of 3' end formation is also decreased when the distance between the two elements is expanded. These results demonstrate that the GU-rich and U-rich elements function synergistically to restore efficient mRNA 3' end formation and that they most likely form a single requisite sequence 3' of the AAUAAA. Furthermore, we show that the effect of the GU-rich and U-rich sequence elements is position-dependent.

Animals↗
PubMed1987

An assessment technique for children with auditory-language processing problems.

The purpose of this study was to develop a new multilayer clinical assessment technique to evaluate auditory-language processing abilities in children. Following a 90-min in-service workshop on auditory-language processing problems, 46 nonhandicapped first-, second-, and third-grade students were referred by their classroom teachers for an evaluation of auditory-language processing abilities. Twelve "normally" achieving first-, second-, and third-grade students were randomly selected as controls. Standardized and nonstandardized measures included a pure tone and impedance test, selected subtests of the Clinical Evaluation of Language Functions (Linguistic Concepts, Relationships and Ambiguities, Oral Directions, Spoken Paragraphs, Word Associations, and Model Sentences), the Goldman-Fristoe-Woodcock (GFW) Memory for Sequence Test, Sound Mimicry Test, Sound-Symbol Association Test, and the GFW Test of Auditory Discrimination. Nonstandardized measures included an Observational Profile of Classroom Communication and an informal language sample. Results indicated 87% of 46 (n = 40) children were identified as having auditory-language processing problems. In-service training was an effective means to heighten teachers' awareness for referring subjects. Additionally, the Observational Profile of Classroom Communication was an effective procedure for teachers to systematically observe and document communication behaviors in the context of the classroom.

Auditory Perceptual Disorders↗
PubMed1986

Responses of somatosensory cortical neurones to tooth pressure and their modulation by transient mouth opening in the cat.

One hundred and thirty two cortical neurones sensitive to mechanical tooth stimulation were detected from the caudal part of the coronal gyrus of the cat. They responded to transient mechanical stimulation of the tooth (TMTst) with initial burst discharges (latency; 14.9 +/- 8.7 ms) and sequential suppression of spontaneous discharges (duration; 218 +/- 142 ms). They also fired strongly at the onset and removal of sustained mechanical stimulation of the tooth (SMTst) with both on and off responses, but the responses for the duration of stimulation were indistinguishable from the spontaneous discharge level. Conditioning stimulation by transient mouth opening (TMOst) inhibited the on and off responses elicited by tooth pressure in 13 (56.5 per cent) of the 23 cortical neurones and in 16 (88.9 per cent) of the 18 neurones tested, respectively. On reversing the conditioning-test sequence, the response elicited by TMOst was inhibited by the onset and removal of SMTst in 12 (52.2 per cent) of the 23 neurones and in 8 (44.4 per cent) of the 18 neurones tested, respectively. The inhibitory period ranged from 50 to 250 ms.

Animals↗
PubMed1980

The recognition site of type II restriction enzyme BglI is interrupted.

The Type II restriction endonuclease BglI recognizes the interrupted DNA sequence 5'-G-C-C-N-N-N-N-N-G-G-C-. This sequence occurs at all locations in over 33 000 base pairs of DNA sequence where the enzyme was found to cut DNA and nowhere else. All six of the specified bases are essential parts of the site since all groups of five of the six bases occur in the DNA sequences tested and none of them are cut by BglI. The length of the block of intervening unspecified positions must be exactly five since all other sizes between zero and 15 occur in the DNA sequences searched and none are cut by BglI. The 5'-terminal nucleotides of BglI cleaved phage G4 replicative form DNA and plasmid pER18 DNA were compared with the DNA sequences near the BglI sites on these DNAs. These results indicated that BglI cuts within the intervening unspecified region and produces single-stranded 3' termini that are three bases long. The BglI recognition site and cleavage points can thus be represented as follows: (Formula: see text). This study of the BglI recognition site was facilitated by the use of inexpensive microcomputers. A system of programs was developed that allowed analysis of over 33 kb of DNA sequences stored on flexible magnetic disks or audio cassettes. While these programs were generally written in the higher level language BASIC, some assembly language subroutines were utilized to reduce execution time.

Bacillus↗
PubMed1991

Octopus program G1X.

The glaucoma program G1 is widely employed by Octopus users. In addition to a specific distribution of test locations, its main advantages are the quick comparison of results with normal values and an easy follow-up. The program, however, is relatively time consuming and, therefore, tiring for some patients. For this reason, the program was modified to 'G1X'. This program is interruptable at any time and provides information, including statistical analysis based on the available data. The test sequence is rearranged in accordance with the importance of the information. The available information, including the confidence limits, is continuously calculated and presented on the screen of the Octopus 1-2-3 during the test procedure. This provides the possibility of adapting the measurement to the patients and their state of health. The principal features as well as clinical applications are described.

Glaucoma↗
PubMed1989

The effectiveness of immediate feedback during the objective structured clinical examination.

Using eight different physical examination or technical stations, 400 examinations were conducted to evaluate the effectiveness of immediate feedback during the Objective Structured Clinical Examination (OSCE). The test group comprised 50 medical students who underwent a standard 4-minute examination followed by 2 minutes of feedback. Immediately following feedback the students repeated an identical 4-minute examination scored by the same examiners. The control group consisted of 50 students from the same class who underwent an identical testing sequence, but instead of receiving feedback, they were instructed to continue their examinations for an additional 2 minutes before repeating the stations. Simple repetition of the task did not significantly improve score (mean increase 2.0%, NS). Extending the testing period from 4 to 6 minutes resulted in a small but significant increase in score (mean 6.7%, P less than 0.001). However, there was a much larger increase in the scores obtained following 2 minutes of immediate feedback compared to pre-feedback performance (mean 26.3%, P less than 0.0001). The majority of students and examiners felt that feedback, as administered in this study, was valuable both as a learning and teaching experience. Short periods of immediate feedback during an OSCE are practical and can improve competency in the performance of criterion-based tasks, at least over the short term. In addition, such feedback provides students with valuable self-assessment that may stimulate further learning.

Clinical Competence↗
PubMed1986

Aftereffects in the responses of cat muscle spindles.

Responses have been recorded from primary endings of muscle spindles in the cat soleus muscle. Changes in spindle responsiveness were measured following a period of conditioning that consisted of a series of rapid stretches or of tetanic ventral root stimulation. In the testing procedure the response of a single spindle afferent was recorded to stimulation of a dynamic fusimotor axon during a slow stretch. Changes in gross afferent discharge coming from the muscle were measured by integrating the activity recorded in dorsal roots. If, after conditioning stretches, the muscle was immediately returned to its initial length, the spindle responded to the test fusimotor stimulation with a high-frequency burst of afferent impulses. If the muscle was held stretched for 3 s after conditioning the response to the brief test tetanus was small or "depressed." It has been suggested that conditioning stretches result in detachment of stable crossbridges in intrafusal fibers and that these bridges then reform over the next few seconds at whatever length the muscle happens to have at the time. When it is long, shortening the muscle back to the initial length leads to the development of slack in intrafusal fibers because of the passive stiffness they have acquired from the presence of the stable bridges. Under these conditions a brief test fusimotor tetanus will lead to a depressed response because the slack must first be taken up before a full response can be generated. It was possible to reverse the depression by interposing an extrafusal contraction during the period between the conditioning and test sequences. It is suggested that lateral compression from the contracting extrafusal fibers and the stretch they impose as they relax reduces any intrafusal slack and thereby reduces the depression. A more quantitative measure of intrafusal slack than the test for depression is to determine the delay in onset of the afferent response to a longer fusimotor tetanus. The delay was short a long initial muscle lengths where, if the muscle was left undisturbed, it soon disappeared completely and spontaneously. It is suggested that at long lengths passive tension in the muscle tends to remove any slack in intrafusal fibers and therefore removes any after effects. The rise in resting discharge of muscle afferents after a conditioning tetanus applied to the ventral root ("postcontraction sensory discharge") can be accounted for by the same hypothesis.(ABSTRACT TRUNCATED AT 400 WORDS)

Action Potentials↗
PubMedDate not supplied

Specificity and variable region cDNA sequence of an isogeneic monoclonal antiidiotype to an anti-alpha(1----6)dextran.

We have characterized a monoclonal isogeneic antiidiotype, IdB5.7, from a BALB/c mouse immunized with the anti-alpha(1----6)dextran C57BL/6 45.21.1. It defined a hapten-inhibitable idiotope expressed on four of the 2 myeloma and 37 hybridoma anti-alpha(1----6)dextrans tested. Sequence comparison of Id+ and Id- anti-alpha(1----6)dextrans suggested that two extra amino acids at VH 100A and 100B and different residues at VH 101 abolish the expression of the idiotope in the Id- anti-alpha(1----6)dextrans. Sequence analysis of the VH of IdB5.7 showed a CDR1 longer than usual and a D segment in CDR3 formed by the fusion of two D minigenes. The IdB5.7 V kappa uses the V kappa 1 germline gene K5.1 with a few substitutions. The D-D fusion in VH CDR3 is a feature which has been reported in several other antiidiotypic antibodies.

Amino Acid Sequence↗
PubMed1991

Sequence effect on incision by (A)BC excinuclease of 4NQO adducts and UV photoproducts.

Nucleotide excision repair in Escherichia coli is initiated by (A)BC excinuclease, an enzyme which incises DNA on both sides of bulky adducts and removes the damaged nucleotide as a 12-13 base long oligomer. The incision pattern of the enzyme was examined using DNA modified by 4-nitroquinoline 1-oxide (4NQO) and UV light. Similar to the cleavage pattern of UV photoproducts and other bulky adducts, the enzyme incises the 8th phosphodiester bond 5' and 5th phosphodiester bond 3' to the 4NQO-modifed base, primarily guanine. The extent of DNA damage by these agents was determined using techniques which quantitatively cleave the DNA or stop at the site of the adduct. By comparison of the intensity of gel bands created by (A)BC excinuclease and the specific cleavage at the damaged site, the efficiency of (A)BC excinuclease incision at 13 different 4NQO-induced adducts and 13 different photoproducts was determined by densitometric scanning. In general, incisions made at 4NQO-induced adducts are proportional to the extent of damage, though the efficiency of cutting throughout the sequence tested varies from 25 to 75%. Incisions made at pyrimidine dimers are less efficient than at 4NQO-adducts, ranging from 13 to 65% incision relative to modification, though most are around 50%. The two (6-4) photoproducts within the region tested are incised more efficiently than any pyrimidine dimer.

4-Nitroquinoline-1-oxide↗
PubMed1985

Properties of some monkey DNA sequences obtained by a procedure that enriches for DNA replication origins.

Twelve clones of monkey DNA obtained by a procedure that enriches 10(3)- to 10(4)-fold for nascent sequences activated early in S phase (G. Kaufmann, M. Zannis-Hadjopoulos, and R. G. Martin, Mol. Cell. Biol. 5:721-727, 1985) have been examined. Only 2 of the 12 ors sequences (origin-enriched sequences) are unique (ors1 and ors8). Three contain the highly reiterated Alu family (ors3, ors9, and ors11). One contains the highly reiterated alpha-satellite family (ors12), but none contain the Kpn family. Those remaining contain middle repetitive sequences. Two examples of the same middle repetitive sequence were found (ors2 and ors6). Three of the middle repetitive sequences (the ors2-ors6 pair, ors5, and ors10) are moderately dispersed; one (ors4) is highly dispersed. The last, ors7, has been mapped to the bona fide replication origin of the D loop of mitochondrial DNA. Of the nine ors sequences tested, half possess snapback (intrachain reannealing) properties.

Animals↗
PubMedDate not supplied

Recognition impairment correlated with short bisynchronous epileptic discharges.

The occurrence of transitory cognitive impairment during diffuse subclinical electroencephalographic (EEG) discharges has been widely documented but the role of the parameters influencing the cognitive performance and the involvement of motor or verbal response in the tasks used is still under debate. Fifteen patients suffering from primary generalized epilepsy with frequent bisynchronous EEG epileptic bursts underwent a shape recognition task during EEG monitoring. The test sequence was as follows: memorandum, pause, and multiple choice set. After pressing the response button, the patient was asked to confirm the choice verbally. The following parameters were considered: geometrical complexity of the shape, chronological position of the burst occurring during the single test, and the duration of discharge ranging from 1 to 3 s. Results showed a significant increase in incorrect responses during the test when discharges occurred, with more errors occurring for difficult than for easy shapes. Neither the discharge position nor the duration of the epileptic burst influenced the performance. Diffuse epileptic activity of short duration produced selective effects on the cognitive process regardless of the motor component of the response.

Adolescent↗
PubMedDate not supplied

The utility of ancillary tests in the diagnosis of jaundice.

The helpfulness of technological tests in the diagnosis of diseases presenting as jaundice was examined using a measure of expected utility derived from decision theory. Data from 243 patients admitted with jaundice yielded a total of 2260 test-results from twenty seven tests used. The results were partitioned into a total of 123 bands. Forty-three bands had a sufficient number of results to be considered for calculation. Eleven out of the 27 tests and 16 of 123 bands gave information recognized to be worthwhile. They contributed to the diagnosis of the 7 commonest diseases, and would permit the selection of the best combination of tests to be performed. The frequency of use of tests did not reflect their utility. A test-sequencing proforma might be a useful aid in the work-up of patients.

Blood Chemical Analysis↗