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Biomedical subjects

N Bernard

Publications and source records attributed to N Bernard.

At least 91 records · Page 5Linked to original sources
PubMed1994

Lactobacillus plantarum ldhL gene: overexpression and deletion.

Lactobacillus plantarum is a lactic acid bacterium that converts pyruvate to L-(+)- and D-(-)-lactate with stereospecific enzymes designated L-(+)- and D-(-)-lactate dehydrogenase (LDH), respectively. A gene (designated ldhL) that encodes L-(+)-lactate dehydrogenase from L. plantarum DG301 was cloned by complementation in Escherichia coli. The nucleotide sequence of the ldhL gene predicted a protein of 320 amino acids closely related to that of Lactobacillus pentosus. A multicopy plasmid bearing the ldhL gene without modification of its expression signals was introduced in L. plantarum. L-LDH activity was increased up to 13-fold through this gene dosage effect. However, this change had hardly any effect on the production of L-(+)- and D-(-)-lactate. A stable chromosomal deletion in the ldhL gene was then constructed in L. plantarum by a two-step homologous recombination process. Inactivation of the gene resulted in the absence of L-LDH activity and in exclusive production of the D isomer of lactate. However, the global concentration of lactate in the culture supernatant remained unchanged.

Amino Acid Sequence↗
PubMed1994

Effects of lisinopril on stress-induced peak blood pressure and sodium excretion: a double-blind controlled study.

A stress test was performed before (S1) and after a 1-month treatment period (S2) in patients with essential hypertension, randomly allocated to receive either an angiotensin-converting enzyme inhibitor (ACEI), lisinopril (n = 10), or placebo (n = 10). The two groups were similar with regard to systolic and diastolic blood pressure (SBP, DBP), body weight, renal function, and 24-h sodium excretion. At S1, stress induced a significant increase in SBP of 18 +/- 9 mm Hg and in DBP of 10 +/- 6 mm Hg and a significant reduction in sodium excretion from 258 +/- 105 to 204 +/- 72 mumol/min. Stress-induced sympathetic stimulation was assessed by a significant increase in urinary norepinephrine (NE) excretion from 21 +/- 10 to 26 +/- 10 micrograms/g creatinine. One-month treatment by placebo did not change stress-induced BP reactivity, sodium retention, or urinary NE excretion. In the lisinopril group, rest and stress BP were significantly reduced by the treatment. Stress-induced sodium retention was higher after 1-month placebo treatment (72 +/- 78 vs 48 +/- 67 mumol/min), whereas this retention was significantly reduced by lisinopril (13 +/- 27 vs 69 +/- 60 mumol/min).

Blood Pressure↗
PubMed1993

T-cell receptor V region beta-chain gene expression in the autoimmune thyroiditis of non-obese diabetic mice.

The non-obese diabetic (NOD) mouse develops both a spontaneous T-cell-mediated autoimmune insulitis and, in addition, a well characterized thyroiditis. We have examined the repertoire of murine T-cell receptor (TCR) variable (V) beta-chain genes used by intrathyroidal T cells with specific oligonucleotides that amplified 17 murine V beta gene families in cDNA samples prepared from intact NOD thyroid tissues. Normal NOD thyroid tissue contained only low levels of TCR V gene mRNA. In contrast, NOD mice with histologic thyroiditis showed the marked expression of up to 3 TCR V beta genes consistent with a restricted T-cell invasion. Sequencing of amplified TCR V beta cDNA showed that within each NOD thyroid sample at least one of the overexpressed V beta gene families was clonally expanded. However, the clonally expanded T-cell V gene family was not consistent in all animals. Even within the same TCR V beta gene families, various D and J segments had been rearranged with open reading frames and together with insertions and deletions gave no significant homology at the nucleotide or amino acid level. In summary, these data showed that the intrathyroidal T-cell infiltrate in NOD mice was markedly biased towards the use of a single, but variable, TCR V gene family within each animal. It also appeared that the choice of the TCR V beta chain determined the intrathyroidal infiltrative process rather than the choice of D and/or J regions. However, there was no consistent use of a single TCR V beta chain. As thyroiditis does not occur uniformly in apparently genetically homogeneous animals, reared under similar environmental conditions, it may not be surprising that different TCR V genes are involved in different animals.

Amino Acid Sequence↗
PubMed1993

Pathogenesis of thyroid-associated ophthalmopathy: an autoimmune disorder of the eye muscle associated with Graves' hyperthyroidism and Hashimoto's thyroiditis.

Thyroid-associated ophthalmopathy, the progressive eye disorder which occurs frequently in patients with Graves' hyperthyroidism and, occasionally, in those with Hashimoto's thyroiditis, may be a two-stage disorder of the eye muscle. In the first stage, which may occur in the great majority of patients with Graves' hyperthyroidism and in an unknown, but probably small, proportion of those with Hashimoto's thyroiditis, antibodies and CD4+ (helper) T lymphocytes reactive with eye muscle and thyroid shared antigens, of which 64-kDa membrane proteins are good candidates, may initiate a mild eye muscle inflammation, manifested as eye muscle swelling on orbital imaging. The second stage, which occurs in about 25% of patients with Graves' hyperthyroidism and in 2% of those with Hashimoto's thyroiditis, may be due to reactivity of cytotoxic antibodies against eye muscle-specific membrane antigens, one of which at approximately 35 kDa appears a likely candidate, and, possibly, cytotoxic T cells in the context of the appropriate class I MHC molecule. Orbital connective tissue inflammation, which plays an important role in the development of progressive orbital inflammation, is likely to be secondary to the eye muscle reaction. The recent cloning of a 64-kDa thyroid and eye muscle antigen which shares significant homology with the muscle protein tropomodulin and mapping of its antibody-reactive epitopes provide structural information about one candidate eye muscle autoantigen and promise for a more rational approach to the diagnosis and management of this common, progressive eye disorder.

Graves Disease↗
PubMed1993

Carcinoid heart disease: two cases of left heart involvement diagnosed by transthoracic and transoesophageal echocardiography.

We report two observations of significant left heart involvement in patients with the carcinoid syndrome assessed by transthoracic and transoesophageal echocardiography. Echocardiographic lesions of this kind have only been reported twice. In the present cases, there was mitral involvement with mitral regurgitation in one case and a mitro-aortic involvement with mitral and aortic regurgitation in the other. The mechanism of left heart lesions is unclear since in both cases no right-to-left cardiac shunt was present, as attested by colour Doppler and saline contrast transoesophageal echocardiography. The location of the primary tumour was unknown in one case and ileal in the other; no pulmonary metastasis was detected. The use of transoesophageal echocardiography might make it possible to detect left-sided cardiac lesions more frequently since they were found in anatomical series, in 30% of patients with carcinoid syndrome.

Aged↗
PubMed1993

Nature of 64 kDa eye muscle and thyroid membrane proteins and their significance in thyroid-associated ophthalmopathy--an hypothesis.

Although a variety of eye muscle antigens are recognized by autoantibodies in the serum from patients with thyroid associated ophthalmopathy (TAO) 64 kDa membrane proteins, which are also expressed in the thyroid, are most closely linked to the development of ophthalmopathy in patients with autoimmune thyroid disease. A cloned 64 kDa protein called 1D, which shares homology with tropomodulin, appears to be closely related to a 64 kDa eye muscle protein identified in immunoblotting and both may be members of a family of cytostructural proteins. The relationship between 64 kDa proteins in eye muscle and thyroid, and its equivalent in somatic skeletal muscle, will only be understood when the various proteins are cloned from expression libraries, sequenced and their consensual and unique domains identified. Since these 64 kDa antigens are expressed in both thyroid and eye muscle, a possible mechanism for the association of ophthalmopathy with autoimmune thyroid disease is immunological cross-reactivity by autoantibodies and sensitized T lymphocytes. Autoantibodies reactive with 64 kDa eye muscle proteins are associated with ophthalmopathy in patients with autoimmune thyroid disorders and predictive of the development of ophthalmopathy in patients with Graves' hyperthyroidism.

Animals↗
PubMed1993

[The reproducibility of the manual checkbite in the wearers of complete dentures].

Thirty-six new complete dentures were remounted by means of check bite records at the time of placement. The mandibular position was recorded three times in each patient by two clinicians using Bite Compound, a thermoplastic material, for the records. After individual transverse horizontal axis localization, the dentures were mounted in an articulator, and subsequently three-dimensional, electronic and computerized measurements were made with a special measuring instrument. In intraindividual comparison the reproducibility of the check bite records resulted in a mean value of 0.37 +/- 0.33 mm, whereby maximum deviations of up to 1.8 mm were observed. Repeated insertion of the maxillary dentures into the hardened impressions of the thermoplastic compound led to an error of 0.04 +/- 0.06 mm. The results of the two clinicians differed only slightly.

Aged↗
PubMed1992

Restricted tissue reactivity of autoantibodies to a 64-kDa eye muscle membrane antigen in thyroid-associated ophthalmopathy.

We studied the tissue specificity of eye muscle (EM) membrane-reactive autoantibodies detected in the serum of patients with thyroid-associated ophthalmopathy (TAO). In preliminary studies, such antibodies were shown to react, in sodium dodecyl sulfate-polyacrylamide gel electrophoresis and Western blotting, with human thyroid (THY) and other human skeletal muscle (HSM) membrane antigens. We carried out absorption with human EM (HEM), THY, and HSM membranes of sera from patients with TAO and autoimmune thyroid disease without ophthalmopathy which reacted with one or more of 55-, 64-, and 95-kDa antigens in pig eye muscle (PEM) membrane in immunoblotting, the majority of which were also cytotoxic to HEM cells in an antibody-dependent cell-mediated cytotoxicity assay. In Western blotting, serum antibodies reactive with PEM membrane antigens of 55, 64, and 95 kDa were cross-absorbed by HEM, THY, and HSM but not by spleen or brain membranes and showed some species specificity, being absorbed by pig and human, but not bovine, EM membranes. When incubated with cultured HEM, THY, and HSM cells in vitro, autoantibodies in TAO sera immunoprecipitated a 64-kDa antigen from the first two tissues, but not from HSM, suggesting a specific binding to autoantigenic epitopes in HEM and THY. Sera from patients with TAO as well as those from patients with thyroid autoimmunity without ophthalmopathy immunoprecipitated a approximately 66-kDa protein, shown to be distinct from the 64-kDa antigen. The restricted immunological cross-reactivity of antibodies to a THY and HEM 64-kDa membrane antigen is discussed in the context of the association of ophthalmopathy with thyroid autoimmunity. Further experiments are needed to show whether autoantibodies to the 64-kDa eye muscle and thyroid shared antigen are cytotoxic, and thus likely to play a major role in the pathogenesis of the eye disease, or just markers of the orbital autoimmune process.

Adult↗
PubMed1992

Significance of antibodies reactive with a 64 kDa eye muscle membrane antigen in patients with thyroid autoimmunity.

SDS-polyacrylamide gel electrophoresis and Western blotting for antibodies reactive with a 64 kDa protein in pig eye muscle membrane was carried out in patients with lid lag and retraction, but no other signs of ophthalmopathy, associated with thyroid disease or nonimmunologic goiter and in patients with Graves' hyperthyroidism without ophthalmopathy who were studied prospectively to determine the relationship of eye muscle antibodies to clinical features of the ophthalmopathy as they appeared in this group of predisposed patients. Seventy-one percent of euthyroid patients with lid lag and retraction but no established ophthalmopathy had detectable serum antibodies to a 64 kDa eye muscle membrane protein. Much smaller proportions had antibodies to proteins of other MW. In normal subjects with previously detectable antibodies to a 64 kDa protein, serum titers, determined by carrying out immunoblotting at serum dilutions of 1:25-1:6400, were low (< or = 1:100) in all cases tested. On the other hand, titers were higher (1:200-1:6400) in 16 of 22 patients with established ophthalmopathy and in 5 of 7 patients with lid lag and retraction tested. Titers tended to be lower in patients with ophthalmopathy of > or = 3 years duration than in those of < or = 1 year duration. Antibody titers were low (1:25) in 6 of 7 patients with Graves' hyperthyroidism without evident eye disease tested. Antibodies to a 64 kDa eye muscle membrane protein were predictive of the development of ophthalmopathy in patients with Graves' hyperthyroidism studied prospectively for periods of 8-42 months.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

Antibodies in the serum of patients with autoimmune thyroid disorders react with a recombinant 98 amino acid fragment of a full length 64 kDa eye muscle membrane protein which is also expressed in the thyroid.

We have tested sera from patients with autoimmune thyroid disorders with or without ophthalmopathy for immunoreactivity, in a dot blot assay, against a recombinant 98 amino acid fragment of a cloned 64 kDa protein, D1, which is expressed in human eye muscle and thyroid, in the form of a Lac Z fusion protein. Tests were positive in 19 out of 40 patients with established thyroid-associated ophthalmopathy (TAO), in 12 out of 21 patients with Graves' hyperthyroidism (GH) without clinically evident ophthalmopathy, in 5 out of 10 patients with thyroid autoimmunity and lid retraction but no other signs of ophthalmopathy, in 4 out of 23 patients with Hashimoto's thyroiditis (HT) without evident ophthalmopathy and in 2 out of 18 patients with benign adenoma or multinodular goitre, but in only 2 out of 37 normal subjects tested. SDS-polyacrylamide gel electrophoresis and Western blotting for an antibody reactive with a 64 kDa antigen in pig eye muscle membranes was also carried out on sera from patients with TAO and GH. While immunoblotting for antibodies reactive with a 64 kDa protein was more often positive in patients with TAO, in whom 58% had serum antibodies which reacted with a 64 kDa protein, this was not the case in patients with GH without eye signs in whom the prevalence of positive immunoblot tests was 35%. Overall there was a fairly close correlation between the two tests although there were many exceptions.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Cell-mediated immunity to orbital tissue antigens in thyroid-associated ophthalmopathy determined using the leukocyte procoagulant activity assay.

While it is generally accepted that thyroid-associated ophthalmopathy (TAO), a progressive inflammatory disorder of the extraocular muscle and orbital connective tissue (OCT), is immunologically mediated the nature of the underlying abnormalities is poorly understood. Although there is considerable evidence for antibody-mediated immunity against both eye muscle (EM) and OCT antigens in TAO a role of cell-mediated immunity (CMI) has not been studied in detail. We have used a new sensitive test for CMI, the leukocyte procoagulant activity (LPCA) assay and tested blood leukocytes from patients with TAO and autoimmune thyroid disease (ATD) without evident ophthalmopathy for reactivity against pig eye muscle (PEM) and human thyroid and OCT membrane and soluble fractions. In some cases human EM fractions were also tested. Preparations of PEM membrane (PEMM) and human thyroid membrane induced a significant LPCA response in both groups of patients. PEM cytosol, human OCT membrane and cytosol and human spleen membrane did not evoke a significant response in either group of patients. There were significant positive correlations in patients with TAO between (i) LPCA in response to PEMM and that to human thyroid membrane and (ii) LPCA in response to human thyroid membrane and that to human EM membrane. In patients with TAO there were no significant associations between LPCA response to PEMM and the detection of serum antibodies to a 64 kDa EM membrane protein in immunoblotting, or between LPCA response to PEMM and the duration or severity of the ophthalmopathy or clinical evidence for eye muscle involvement. These findings confirm a role of cell-mediated immunity against eye muscle antigens in thyroid-associated ophthalmopathy.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Urinary trypsin inhibitory activity for the diagnosis of bacterial infection: a prospective study in 690 patients.

OBJECTIVES: During the acute phase response, interleukin-1 induces production of inter-alpha-trypsin inhibitor. The measurement of urinary trypsin inhibitory activity which results from the effects of inter-alpha-trypsin inhibitor degradation products is easy, quick and inexpensive. We conducted a prospective study to investigate its value as a diagnostic tool in comparison with C-reactive protein. METHODS: Comparisons were made in 690 consecutive patients at admission to a department of internal medicine. RESULTS: The level of urinary trypsin inhibitory activity was significantly higher in patients with bacterial infection (mean = 123 IU/g creatinine) than in patients with either viral infection (34 IU), cancer (50 IU), elevated erythrocyte sedimentation rate without infection (45 IU), miscellaneous non-inflammatory diseases (27 IU) or in non-organic controls (19 IU) (Dunnet's test, p << 0.01). The receiver operating characteristic curve showed that sensitivity and specificity of urinary trypsin inhibitory activity were higher than those of C-Reactive protein for the diagnosis of bacterial infection. For levels > or = 60 IU, sensitivity was 75% and specificity 89%. Urinary trypsin inhibitory activity levels fell within 2 days in patients treated for acute bacterial infection. CONCLUSION: Urinary trypsin inhibitory activity could be a useful marker of bacterial infection particularly in patients with fever of unknown origin and/or elevated erythrocyte sedimentation rate.

Alpha-Globulins↗
PubMed1992

[The reproducibility of arrow-point registration in full-dentition subjects depending on the recording material].

The reproducibility of the intraoral central bearing point method was measured in 46 dentate subjects with a healthy stomatognathic system. Nine complete registrations were carried out on each volunteer, while three different materials were used for fixing the upper to the lower jaw. The occlusal records were examined in the condylar area on a specially designed articulator. Two therapists took part in this study. The shifts of the condylar spheres in all three spatial directions were found as follows: Ramitec 0.14 +/- 0.16 mm, Super-Bite 0.15 +/- 0.14 mm and Bite Compound 0.15 +/- 0.16 mm. The movements of the condylar spheres in space were calculated. They amounted to 0.28 +/- 0.23 mm when using Ramitec, 0.28 +/- 0.20 mm when using Super Bite and 0.31 +/- 0.23 mm when using Bite Compound. Statistically, the differences between the data of the three materials were not significant. Also, the results of our random sample were independent of the therapist.

Dental Articulators↗
PubMed1991

Cloning of the D-lactate dehydrogenase gene from Lactobacillus delbrueckii subsp. bulgaricus by complementation in Escherichia coli.

A strain of Escherichia coli (FMJ144) deficient for pyruvate formate lyase and lactate dehydrogenase (LDH) was complemented with a genomic DNA library from Lactobacillus delbrueckii subsp. bulgaricus. One positive cloned showed LDH activity and production of D(-)lactate was demonstrated. The nucleotide sequence of the D-LDH gene (ldhA) revealed the spontaneous insertion of an E. coli insertion sequence IS2 upstream of the gene coding region. The open reading frame encoded a 333-amino acid protein, showing no similarity with known L-LDH sequences but closely related to L. casei D-hydroxyisocaproate dehydrogenase (D-HicDH).

Amino Acid Sequence↗