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PubMed1992

Body composition, nitrogen metabolism, and energy utilization with feeding of mildly restricted (4.2 MJ/d) and severely restricted (2.1 MJ/d) isonitrogenous diets.

To determine the effects on weight loss of feeding isonitrogenous diets in mildly restricted (4.2 MJ/d) and severely restricted (2.1 MJ/d) amounts, we measured body composition, weight loss-energy deficit ratio, and nitrogen metabolism in 14 obese women housed in a metabolic ward consuming hypoenergetic diets for 21 d. Subjects consumed either a 4.2-MJ/d diet (50 g protein, 175 g carbohydrate) or a 2.1-MJ/d diet (50 g protein, 75 g carbohydrate). Body composition and leucine oxidation and turnover were determined before and after weight loss. Energy deficit was calculated from resting metabolic rates. Subjects fed the 2.1-MJ/d diet showed a greater weight loss (6.1 +/- 0.5 vs 4.5 +/- 0.5 kg; mean +/- SE, P less than 0.05) and fat loss (3.9 +/- 0.3 vs 3.0 +/- 0.3 kg, P less than 0.05). Weight loss-energy deficit ratio was the same with both diets. Nitrogen balance and leucine oxidation and turnover were similar in both groups. We conclude that with feeding of isonitrogenous hypoenergetic diets, severe restriction of energy content (2.1 MJ/d, 75 g carbohydrate) will enhance weight and fat loss without increasing nitrogen loss compared with mild restriction of energy (4.2 MJ/d).

Body Composition↗

PubMed1991

Characterization of Rrh4273I, a restriction-modification system of Rhodococcus rhodochrous ATCC 4273 (Nocardia corallina) which recognizes the same sequence as the Streptomyces albus G SalI restriction-modification system.

Rhodococcus rhodochrous ATCC 4275 (Nocardia corallina) has a restriction-modification system with the same recognition sequence, methylation site and cleavage site as the SalI restriction-modification system. Both the restriction endonuclease and the DNA-methyltransferase (DNA-MTase) have been partially purified and characterized. The nuclease has requirements of activity similar to SalI, and a native Mr of about 46,000. The DNA-MTase is a protein with an Mr of about 67,000. No DNA homology was detected between the cloned salI restriction-modification genes of Streptomyces albus and R. rhodochrous chromosomal DNA.

Base Sequence↗

PubMed1992

Overlapping epitopes that are recognized by CD8+ HLA class I-restricted and CD4+ class II-restricted cytotoxic T lymphocytes are contained within an influenza nucleoprotein peptide.

Viral epitopes that are recognized by both HLA class I-restricted and class II-restricted T cells have been defined for a type A influenza virus nucleoprotein (NP) peptide. CD8+ and CD4+ CTL lines have been generated against a synthetic peptide encompassing residues 335 to 349 of NP that are restricted by HLA-B37 and HLA-DQw5, respectively. Both of these CTL populations were capable of specifically lysing influenza A virus-infected targets, indicating that a naturally processed NP peptide(s) was being mimicked by the NP (335-349) peptide. Amino acid residues that are critical for recognition of this NP determinant in the context of HLA-B37 and HLA-DQw5 were investigated by the use of panels of truncated and alanine-substituted NP peptides. The results demonstrate that: 1) truncations in the amino- or carboxy-terminal ends differentially affect CD8+ and CD4+ CTL recognition; 2) the NP (335-349) sequence contains two octapeptide epitopes that share a core of six amino acid residues (NP 338-343); and 3) alanine substitutions at five of these residues abrogated recognition by at least one of the CD8+ and CD4+ CTL lines. Thus, these class I- and class II-restricted CTL lines recognize similar but distinct epitopes, and different structural features of the NP peptide are required for presentation by HLA-B37 and HLA-DQw5. Comparison of the amino acid sequences of the NP peptide presented by HLA-B37 and HLA-DQw5 with other peptides known to be presented by both class I and class II molecules revealed a common motif among these peptides.

Amino Acid Sequence↗

PubMed1990

DNP-specific/class I MHC-restricted suppressor molecules bear determinants of the T cell receptor alpha- and beta-chains. The V beta 8+ chain dictates restriction to either K or D.

To examine in greater detail the relationship between DNP-specific/class I MHC-restricted suppressor molecules (SSF) that inhibit contact sensitivity to 2,4-dinitrofluorobenzene and the receptors on the T cells that produce them, we have generated two T cell hybridomas that can be induced to produce and secrete these molecules. In order to become activated to produce SSF, the Ts 15.15 and 15.31 cells required recognition of complexes of DNP/Dd on presenting cells. The suppressor molecules produced by each of the Ts hybrids had the same specificity, recognizing DNP/Dd on cells in the immune lymph node cell target population. The activation of the Ts hybrids was blocked when the cells were treated with the anti-V beta 8 antibody F23.1 before coculture with the DNP-presenting cells. Reduction of the 15.15 and 15.31 SSF followed by affinity chromatography on DNP-bovine-gamma-globulin-Sepharose beads indicated that these molecules are dimers and that one of the chains (Ag-binding(AgB] binds to cellfree DNP and one (non-Ag-binding (NAgB) chain) does not. The AgB chain was found to express an epitope bound by a mAb specific for a TCR alpha-chain-constant region determinant. Alternatively, the NAgB chain expressed an epitope bound by the anti-V beta 8 mAb F23.1. Active hybrid suppressor molecules were generated by combining the NAgB chain from a DNP-specific/H-2Kd-restricted SSF (produced by Ts hybridoma 3-10) with the AgB chain from Ts 15.31 and by combining the NAgB chain from Ts cell 15.15 with the 3-10 AgB chain. In each case, the class I MHC element (i.e., Kd or Dd) restricting the activity of these hybrid SSF correlated with the source of the V beta 8+, NAgB chain. Thus, these secreted immunoregulatory molecules have the Ag/MHC specificity of the T cells producing them and are structurally and serologically related to the TCR-alpha/beta. The results further suggest that for some hapten-specific/class I MHC-restricted TCR, the alpha-chain may have avidity for the hapten and the beta-chain may dictate the MHC restriction element (K or D) recognized by the receptor.

Animals↗

PubMed1992

Molecular epidemiology of group B streptococcal infections: use of restriction endonuclease analysis of chromosomal DNA and DNA restriction fragment length polymorphisms of ribosomal RNA genes (ribotyping).

Epidemiologic investigation of group B streptococcal (GBS) infections has been limited by the lack of a discriminatory typing system. Therefore, the use of restriction endonuclease analysis of chromosomal DNA (REAC) and DNA restriction fragment length polymorphisms of rRNA genes (ribotyping) to subtype molecularly GBS isolates associated with human invasive disease was investigated. Chromosomal DNA of selected GBS isolates was initially digested with 24 different restriction enzymes. HhaI gave the best discrimination of hybridization banding patterns (ribotypes) and was used with all study isolates. Ribotyping and REAC differentiated among isolates of the same and different serotypes. Nine ribotype patterns were noted among the 76 isolates studied, including 4 among serotype Ia/c and 4 additional ribotypes among serotype III isolates. Epidemiologically related isolates (e.g., mother-infant or twin-twin pairs) had identical REAC and ribotype patterns. Epidemiologically unrelated isolates with the same ribotype usually had different REAC patterns, suggesting that REAC may be a more sensitive technique for strain differentiation. REAC and ribotyping were reproducible and proved to be successful molecular epidemiologic methods for subtyping GBS.

Adult↗

PubMed2026

Effects of intensive lifestyle interventions with calorie-carbohydrate-restricted diet versus time-restricted eating on appetite and binge eating in type 2 diabetes: A randomized controlled trial.

The impact of intensive lifestyle interventions on appetite regulation and binge eating in individuals with type 2 diabetes (T2D) remains unclear. This study evaluated the effects of combined lifestyle interventions on appetite responses and binge eating in overweight or obese adults with T2D. In a randomized trial, 120 participants with T2D were allocated to three groups (n = 40 each): (1) Calorie-carbohydrate restriction (CCR), (2) Time-restricted eating with CCR (TRE + CCR), or (3) Control. Intervention groups received structured exercise and behavioral education based on the Information-Motivation-Behavioral Skills model. Appetite perceptions (hunger, satiety, desire to eat, and prospective food consumption) and binge eating (Binge Eating Scale; BES and objective binge episodes) were evaluated at baseline, week 12, and week 24 using linear mixed models. Both CCR and TRE + CCR significantly improved subjective appetite compared with the control group at 12 and 24 weeks (all p < 0.01). At 24 weeks, hunger decreased by -24.1 mm (95% CI: -35.8, -12.5) in the CCR group and -32.7 mm (95% CI: -44.2, -21.3) in the TRE + CCR group. Satiety also increased by 21.7 mm (95% CI: 9.46, 33.9) and 29.4 mm (95% CI: 17.4, 41.4), respectively. Significant reductions were observed for desire to eat and prospective food consumption. In contrast, changes in BES and objective binge episodes were not significantly different between groups at any time point. No significant differences were detected between the CCR and the TRE + CCR groups. Intensive lifestyle interventions incorporating CCR or TRE + CCR effectively reduced appetite in adults with T2D but did not significantly affect binge eating. Future research should target individuals with higher baseline BES scores to clarify potential benefits for binge eating behavior.

Humans↗

PubMed1990

An immunodominant class I-restricted cytotoxic T lymphocyte determinant of human immunodeficiency virus type 1 induces CD4 class II-restricted help for itself.

We have observed that a peptide corresponding to an immunodominant epitope of the HIV-1 envelope protein recognized by class I MHC-restricted CD8+ CTL can also induce T cell help for itself. The help is necessary for restimulation of CTL precursors in vitro with peptide alone in the absence of exogenous lymphokines, can be removed by depletion of CD4+ T cells, and can be replaced by exogenous IL-2. Whereas the CTL in BALB/c or B10. D2 mice are restricted by the class I molecule Dd, the Th cells are restricted by the class II molecule Ad, and the help can be blocked by anti-Ad mAb. To examine the genetic regulation of the induction of help, we studied B10.A mice that share the class I Dd molecule, but have different class II molecules, Ak and Ek. Spleen cells of immune B10.A mice behave like CD4-depleted BALB/c spleen cells in that they cannot be restimulated in vitro by the peptide alone, but can with peptide plus IL-2. Therefore, in the absence of exogenous lymphokines, peptide-specific help is necessary for restimulation with this immunodominant CTL epitope peptide, and in H-2d mice, this peptide stimulates help for itself as well as CTL. We speculate on the implications of these findings for the immunodominance of this peptide in H-2d mice, and for the selective advantage of pairing certain class I and class II molecules in an MHC haplotype.

Animals↗

PubMed1991

Characterization of noncapsulate Haemophilus influenzae by whole-cell polypeptide profiles, restriction endonuclease analysis, and rRNA gene restriction patterns.

Thirty-four clinical isolates of noncapsulate Haemophilus influenzae representing isolates with either related or dissimilar patterns of whole-cell polypeptide profiles on sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) were further characterized by restriction enzyme analysis (REA) and rRNA gene restriction patterns. Total cellular DNA was extracted by a rapid, microcentrifuge-scale method and digested with BamHI, which gave a pattern of about 18 discrete bands. This confirmed the five closely related groupings suggested by SDS-PAGE. Isolates dissimilar by SDS-PAGE were also distinguishable by REA. However, there was no correlation between the degrees of similarity estimated from whole-cell polypeptide profiles and those obtained from REA for the dissimilar isolates. Therefore, inferences of genetic relatedness made on the basis of these data should be interpreted with caution. rRNA gene restriction patterns also confirmed the groupings suggested by the other two techniques. We conclude that the three methods were highly discriminatory and that whole-cell polypeptide patterns or REA with BamHI would be appropriate techniques for epidemiological studies of noncapsulate H. influenzae.

Bacterial Proteins↗

PubMed1990

Hae III--a suitable restriction endonuclease for restriction fragment length polymorphism analysis of biological evidence samples.

Hae III has been selected by our laboratories as the restriction endonuclease of choice for restriction fragment length polymorphism analysis of forensic science samples. The enzyme is compatible with the D2S44 probe system and generates relatively small DNA fragments for that marker system. Similarly, Hae III is compatible with several other independent polymorphic loci, including D1S7, D4S139, D16S85, D17S74, D17S79, D14S13, and D20S15. Hae III is functional under a variety of adverse conditions for DNA digestion and is not affected by the methylation pattern in mammals. Finally, Hae III is a relatively inexpensive restriction endonuclease.

Base Sequence↗

PubMed1990

Analysis of left ventricular diastolic function by the pressure-volume relation in cases with idiopathic restrictive cardiomyopathy and amyloid restrictive cardiomyopathy.

To assess left ventricular (LV) diastolic function in idiopathic restrictive cardiomyopathy (IRCM) and amyloid restrictive cardiomyopathy (ARCM), we analyzed LV cineangiograms and pressures (tip manometer) in two patients, one with IRCM and the other with ARCM. LV volume and instantaneous rate of change of volume were derived from frame-by-frame analyses of angiograms. LV relaxation was assessed by the time constant of isovolumic pressure decay. LV compliance was evaluated by the pressure-volume relationship. From these analyses, we conclude as follows: (1) In restrictive cardiomyopathy (RCM), LV diastolic dysfunction may be characterized by impaired relaxation and decreased compliance; (2) LV diastolic filling was minimally impaired or normal in both conditions; (3) The ventricular diastolic pressure wave form of "dip and plateau" seemed not to be a characteristic sign in RCM.

Blood Pressure↗

PubMed1992

Increased frequency of 2,4,6-trinitrophenyl (TNP)-specific, H-2b-restricted cytotoxic T lymphocyte precursors in transgenic mice expressing a T cell receptor beta chain gene from an H-2b-restricted, TNP-specific cytolytic T cell clone.

T cell antigen receptors (TcR) expressing V alpha 10/J alpha BBM142 genes in association with beta chains containing J beta 2.6 elements were found to be predominant among 2,4,6-trinitrophenyl (TNP)-specific, H-2b-restricted cytolytic T cell lines (CTL). To assess the relative contribution of the TcR beta chain to the TNP specificity as well as to the selection of the respective TcR alpha chain elements we generated transgenic mice expressing the TcR beta chain of the H-2b/TNP-specific CTL clone BT7.4.1. The TcR of this clone does not belong to the type predominant among H-2b/TNP-specific CTL, as it consists of an alpha chain encoded by a V alpha 8/J alpha DO gene rearrangement and a V beta 2/J beta 1.1-containing beta chain. In the transgenic mice almost all T cells exclusively express the transgenic V beta 2 gene, as a result of allelic exclusion. TNP-specific, H-2b-restricted precursors were found at 7- to 8-fold higher frequency in these mice as compared with non-transgenic littermates. In H-2b/d heterozygous transgenic mice, an increased frequency of TNP-specific precursors was found only in H-2b, but not in H-2d-restricted CTL. Analysis of H-2b/TNP-specific CTL lines derived from V beta 2-transgenic mice indicated a preferential association of the transgenic TcR beta chain with endogenous alpha chains encoded by V alpha 8 and J alpha BBM142 genes. This suggests that the hapten TNP is recognized like typical peptide antigens by combinatorial TcR alpha and beta contact sites.

Alleles↗

PubMed1978

Complement C3 convertase: cell surface restriction of beta1H control and generation of restriction on neuraminidase-treated cells.

The alternative or properdin pathway of complement is primarily controlled by the endopeptidase C3b inactivator (C3bINA) and the nonproteolytic glycoprotein beta1H. The molecular mechanisms of control were investigated by performing binding studies of radiolabeled complement proteins to C3b bearing sheep erythrocytes (E(S)C3b). C3b was found to have distinct binding sites for beta1H, C3bINA, Factor B, and properdin. beta1H binding increased C3bINA binding 30-fold, while Factor B binding prevented C3bINA action on C3b and was competitive with beta1H binding. Properdin binding, which facilitates Factor B interaction with C3b, had no effect on the beta1H and C3bINA sites. Activators such as rabbit erythrocytes (E(R)) have previously been shown to interfere with the effectiveness of the control by C3bINA and beta1H, thereby allowing unrestricted formation of C3 convertase. Such restriction of control does not occur on the surface of E(S), a nonactivator of the alternative pathway. On the basis of comparative binding studies, restriction of control is explained entirely by reduced binding of beta1H to E(R)C3b relative to E(S)C3b. Access of properdin, Factor B, C3bINA, and the Fab fragment of anti-C3 to the two cell types was unrestricted. Restriction of beta1H control could be generated on the surface of E(S) by removal of cell-surface sialic acid with neuraminidase (acylneuraminyl hydrolase; EC 3.2.1.18). This enzymatic treatment converted E(S) from a nonactivator to an activator of the alternative pathway.

Binding Sites↗

PubMed1990

Human protectin (CD59), an 18-20-kD homologous complement restriction factor, does not restrict perforin-mediated lysis.

Human protectin (CD59) is an 18-20-kD membrane glycoprotein that restricts lysis of human erythrocytes and leukocytes by homologous complement. By directly incorporating protectin into membranes of heterologous cells we observed that protectin did not prevent perforin-mediated killing, whereas complement killing was effectively restricted. Further, no significant enhancement of cell-mediated killing or target killing by purified perforin was observed with anti-protectin antibodies. Thus, in contrast with complement lysis, restriction of lysis by protectin does not apply to cell-mediated killing.

Animals↗

PubMed1990

The predominance of CD8+ T cells after infection with measles virus suggests a role for CD8+ class I MHC-restricted cytotoxic T lymphocytes (CTL) in recovery from measles. Clonal analyses of human CD8+ class I MHC-restricted CTL.

Stimulation of PBMC, in children recovering from acute measles, with autologous EBV-transformed and measles virus (MV)-infected lymphoblastoid cell lines (B-LCL) expanded primarily MV-specific CD8+ T cells. A large number of CD8+ T cell clones were obtained either by passaging of bulk cultures at limiting dilutions or by direct cloning of PBMC without previous stimulation in bulk culture. The MV-specific CD8+ T cell clones responding in a proliferative and a CTL assay were found to be class I MHC restricted. In contrast, CD4+ MV-specific T cell clones, which were generated by the same protocol, recognized MV in association with class II MHC molecules. Analysis of processing requirements for Ag presentation to CD8+ and CD4+ T cell clones, measured by the effect of chloroquine in a proliferative T cell response, revealed that both types of T cells recognized MV Ag processed via the endogenous/cytoplasmic pathway. Thus, these studies indicate that, as in most other viral infections and in contrast to previous suggestions, the class I MHC-restricted CTL response by CD8+ T cells may be an important factor in the control and elimination of MV infection. Therefore, the role proposed for CD4+ class II-restricted T cells in recovery from measles needs to be reevaluated.

Antigen-Presenting Cells↗

PubMed1977

[Long-term study on the influence of running exercise, food restriction, running exercise + food restriction and of parenterally applicated testis cells on age-parameters of the rat (author's transl)].

Preliminary results of a long-term study on 1100 male Sprague-Dawley rats are presented, showing the influence of running exercise, of restricted diet, of both of these together and of the s.c. application of lypholized testis cells. Up to now animals aged 9, 15 and 24 mths were investigated. The test-animals were exposed to the experimental conditions from their 6th month of life. The running exercise was carried out on a treadmill (30 m at a speed of 25 m/min, horizontal) 5 days a week. A food restriction of about 20% was achieved by 2 fasting-days a week. The lyophilized testis cells were injected for the first time at an age of 9 mths and afterwards in 6 mths intervals. Between the injection and the assessment of the age-parameters there was an interval of 6 mths. S o fare the following parameters of the comprehensive test-program have been evaluated: 1) running performance in m (treadmill, 20 m/min, ascent 15 degrees), 2) motor activity (Animex Activity Meter), 3) chemical contraction-relaxation of tail-tendon-fibers, 4) total lipids and total cholesterol in the plasma. The results obtained so far show that a mild regular training, moderate food restriction and the s.c. application of testis-cells are able to cause a significant shift in the dirction of a younger biological age in at least some of the age parameters. The action of the testis-cells seems to affect most of the age parameters but shows the tendency to be more distinct at a higher age. More concrete statements about the influence on the biological age or the vitality will only be possible after the multivariate analysis of the results.

Age Factors↗

PubMed1975

Restriction and modification in B. subtilis. Nucleotide sequence recognised by restriction endonuclease R. Bsu R from strain R.

Restriction endonuclease R from Bacillus subtilis strain R cleaves nonmodified SPP 1 DNA in approximately 80, and lambda DNA in about 200 different sites. DNA digests with this endonuclease and with endonuclease Hae III from Haemophilus aegyptius show identical fragmentation patterns on gel electrophoresis, indicating that the two enzymes recognise the same nucleotide sequence. The polynucleotide kinase reaction was used in conjunction with two-dimensional ionophoretic nucleotide mapping methods to identify the 5'-nucleotide sequences at the sites of cleavage by the B. subtilis restriction endonuclease. The results show that the recognition sequence is (see article) where arrows indicate the points of strand scission. Each of the four possible nucleotides can occur in the positions flanking the recognition site.

Bacillus subtilis↗

PubMed1991

The distribution of restriction fragment lengths for non-overlapping restriction sites in a random DNA sequence model.

Overlapping subsequences in a DNA sequence are not independent even if independence is supposed for the single nucleotides. Therefore the often used geometric distribution for the length of restriction fragments is not exact. The exact distribution of this random variable is derived for non-overlapping restriction sites in a DNA sequence with an infinite (or very large) number of nucleotides. Correction to the finite case is easy. It is shown that the simple geometric distribution is a good approximation as long as the basic probability for the occurrence of the recognition sequence at a given site is small.

Base Sequence↗

PubMed1991

Partial restriction map of salmonid herpesvirus (Oncorhynchus masou virus) DNA for three restriction enzymes BamHI, EcoRI and XhoI.

Cleavage of Oncorhynchus masou virus (OMV) DNA with restriction endonucleases BamHI, EcoRI, and XhoI resulted in 28, 26 and 17 fragments, respectively. Based on the molecular weights of digested fragments and those molar ratio. OMV DNA showed the molecular weight of about 100 x 10(6). Twenty out of 28 BamHI fragments of OMV DNA were successfully cloned into pBR322 vector. Restriction map of OMV DNA was constructed by blotting hybridization and double-digestion. The data suggested that terminal repeat of the end fragments of OMV DNA molecule was not existence.

Animals↗