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Biomedical subjects

M A Bernard

Publications and source records attributed to M A Bernard.

At least 19 recordsLinked to original sources
PubMed2003

Analysis of proteins with caseinolytic activity in a human stratum corneum extract revealed a yet unidentified cysteine protease and identified the so-called "stratum corneum thiol protease" as cathepsin l2.

Desquamation is described as a protease-dependent phenomenon where serine proteases with a basic pH optimum play a key role. Recently proteases with an acidic pH optimum were identified in the stratumcorneum and associated with desquamation, e.g., cathepsin D and the stratum corneum thiol protease. The purpose of this study was to investigate if human stratum corneum contains proteases different from the above, exhibiting similar properties. After gel filtration, we identified four distinct proteolytic activities in a human stratum corneum extract, a cathepsin-E-like activity (80 kDa), a cathepsin-D activity (40 kDa), a yet unknown cathepsin-L-like form (28 kDa) exhibiting the highest caseinolytic activity, and a chymotrypsin-like protein (24 kDa) containing the acidic activity of the well described stratum corneum chymotryptic enzyme. We named the new 28 kDa protease stratum corneum cathepsin-L-like enzyme. Characterization of stratum corneum cathepsin-L-like enzyme provided clear evidence that this new protease, despite its membership to the cathepsin-L-like family, is distinct from cathepsin L and from the recently described stratum corneum thiol protease. Its ability to hydrolyze corneodesmosin, a marker of corneocyte cohesion, was in favor of a role of stratum corneum cathepsin-L-like enzyme in the desquamation process. A more detailed analysis did not allow us to identify stratum corneum cathepsin-L-like enzyme at the molecular level but revealed that stratum corneum thiol protease is identical with the recently described cathepsin L2 protease. Reverse transcription polymerase chain reaction studies and the use of a specific antibody revealed that, in contrast to earlier reports, expression of stratum corneum thiol protease in human epidermis is not related to keratinocyte differentiation. Our results indicate that the stratum corneum thiol protease is probably expressed as a pro-enzyme in the lower layers of the epidermis and in part activated by a yet unidentified mechanism in the upper layers during keratinocyte differentiation.

Amino Acid Sequence↗
PubMed2001

Diminished levels of the putative tumor suppressor proteins EXT1 and EXT2 in exostosis chondrocytes.

The EXT family of putative tumor suppressor genes affect endochondral bone growth, and mutations in EXT1 and EXT2 genes cause the autosomal dominant disorder Hereditary Multiple Exostoses (HME). Loss of heterozygosity (LOH) of these genes plays a role in the development of exostoses and chondrosarcomas. In this study, we characterized EXT genes in 11 exostosis chondrocyte strains using LOH and mutational analyses. We also determined subcellular localization and quantitation of EXT1 and EXT2 proteins by immunocytochemistry using antibodies raised against unique peptide epitopes. In an isolated non-HME exostosis, we detected three genetic hits: deletion of one EXT1 gene, a net 21-bp deletion within the other EXT1 gene and a deletion in intron 1 causing loss of gene product. Diminished levels of EXT1 and EXT2 protein were found in 9 (82%) and 5 (45%) exostosis chondrocyte strains, respectively, and 4 (36%) were deficient in levels of both proteins. Although we found mutations in exostosis chondrocytes, mutational analysis alone did not predict all the observed decreases in EXT gene products in exostosis chondrocytes, suggesting additional genetic mutations. Moreover, exostosis chondrocytes exhibit an unusual cellular phenotype characterized by abnormal actin bundles in the cytoplasm. These results suggest that multiple mutational steps are involved in exostosis development and that EXT genes play a role in cell signaling related to chondrocyte cytoskeleton regulation.

Actins↗
PubMed2001

Effects of a community-based intervention to increase activity in American Indian elders.

The purpose of this study was to evaluate the efficacy of a community-based exercise course applied to a group of American Indians (AI) who, because of physician recommendation and/or self-motivation, desired to increase their physical activity. Changes in physiological measurements and self-perceived measurements were determined following a moderate-intensity exercise program implemented through a randomized controlled trial to a population of American Indian elders between the ages of 55 and 75 living in an urban area. It was hypothesized that the exercise subjects would show improvement in all of the study variables examined, including three subjective measurements in emotional health, seven subjective measurements in physical health, and several physiological indices. The subjects participated in a six-week exercise class designed for healthy elderly persons as well as for those struggling from arthritis, heart disease, obesity, and/or non-insulin dependent diabetes. Results were measured using both subjective self-perceived and objective physiological measurements; T-tests were used to analyze the data, using subjects as their own controls and using a separate control group. Following the intervention, the exercise participants significantly improved their self-perceived physical health (p = 0.001), emotional health (p = 0.023), and personal appearance (p = 0.025) when compared with baseline values. The exercise subjects also significantly increased the self-perceived frequency with which they performed chores that gave them exercise (p = 0.035) and significantly increased the self-perceived frequency that they participated in activities specifically for exercise (p = 0.023) when compared with pre-intervention measurements. A corresponding trend in objective indices was also observed: following the intervention period, exercise participants were found to significantly lower their systolic blood pressure (p = 0.046) and significantly lower their respirations (p = 0.048) as compared with initial values. Findings of this study suggest that senior Al adults who participated in the exercise program subjectively and objectively improved their health status. The authors think that this type of program would be an excellent resource for physicians to recommend to their eldrly patients in need of increased physical activity. A literature search found no previously published clinical data documenting the response of Al elders to excercises that developed flexibility, muscular strength, and muscular endurance.

Aged↗
PubMed2000

Identification and cloning of a new calmodulin-like protein from human epidermis.

After separating by two-dimensional gel electrophoresis an extract of total proteins from human stratum corneum, two spots were extracted and analyzed for their peptide sequence. The resulting internal protein sequences provided evidence for the identification of a new calcium-binding protein. Cloning of the corresponding full-length cDNA was achieved by reverse transcriptase-polymerase chain reaction using two keratinocyte libraries, one from proliferating cultured keratinocytes and one from differentiated keratinocytes of reconstructed human epidermis. The cDNA had an open reading frame encoding a new calcium-binding protein of 146 amino acids, a member of the calmodulin family. We named this new protein calmodulin-like skin protein (CLSP), since reverse transcriptase-polymerase chain reaction studies of CLSP expression in 10 different human tissues revealed that this protein was particularly abundant in the epidermis where its expression is directly related to keratinocyte differentiation. Expression of the cloned cDNA in Escherichia coli yielded a recombinant protein which allowed its further characterization. rCLSP is able to bind calcium, and similarly to calmodulin, exposes thereafter hydrophobic parts which most likely interact with target proteins. Epidermal proteins retained by CaM affinity column are quantitatively and qualitatively distinct from those of the rCLSP column. Sequencing of a rCLSP affinity purified protein revealed 100% identity with transglutaminase 3, a key enzyme in terminal differentiation, indicating an important role of CLSP in this process.

Amino Acid Sequence↗
PubMed2000

Metabolic functions of microbial nucleoside diphosphate kinases.

This article summarizes research from our laboratory on two aspects of the biochemistry of nucleoside diphosphate kinase from Escherichia coli--first, its interactions with several T4 bacteriophage-coded enzymes, as part of a multienzyme complex for deoxyribonucleoside triphosphate biosynthesis. We identify some of the specific interactions and discuss whether the complex is linked physically or functionally with the T4 DNA replication machinery, or replisome. Second, we discuss phenotypes of an E. coli mutant strain carrying a targeted deletion of ndk, the structural gene for nucleoside diphosphate kinase. How do bacteria lacking this essential housekeeping enzyme synthesize nucleoside triphosphates? In view of the specific interactions of nucleoside diphosphate kinase with T4 enzymes of DNA metabolism, how does T4 multiply after infection of this host? Finally, the ndk disruption strain has highly biased nucleoside triphosphate pools, including elevations of the CTP and dCTP pools of 7- and 23-fold, respectively. Accompanied by these biased nucleotide pools is a strong mutator phenotype. What is the biochemical basis for the pool abnormalities and what are the mutagenic mechanisms? We conclude with brief references to related work in other laboratories.

Bacteriophage T4↗
PubMed2000

Cardiac troponin I is reliable with immediate but not medium-term cardiac complications after abdominal aortic repair.

BACKGROUND: The diagnosis of cardiac complications is particularly challenging in the postoperative course of non-cardiac surgery. Follow-up of patients suggests that silent or symptomatic postoperative myocardial infarction have similar short-term outcomes. Cardiac troponin I (cTnI) has been reported as being a sensitive and specific marker of these complications. METHODS: We conducted a prospective study to determine the cut-off values of cTnI which may predict cardiac complications, i: in the postoperative period until discharge, and ii: during a 1-year period after aortic surgery. Three hundred and twenty-nine consecutive patients undergoing infrarenal aortic surgery were included over a 2-year period in a single center. cTnI was measured at recovery and on the 1st, 2nd and 3rd postoperative days. The presence or absence of cardiac complications was classified by reviewers who had no knowledge of cTnI. For evaluation of the ideal discrimination value of cTnI between the complicated and uncomplicated patient groups, we calculated receiver-operator characteristics for the mean values of the peak of cTnI. RESULTS: Thirteen patients (4%) developed 19 postoperative cardiac complications. Thirteen patients (4%) died in the postoperative period. Nine patients (3%) developed 10 cardiac complications during the 1-year follow-up in 316 patients. In 280 patients, cTnI was below 0.5 ng/ml, in 22 patients between 0.5 and 1.5 ng/ml and the 27 remaining patients had a cTnI higher than 1.5 ng/ml. The area under the curve for postoperative cardiac complications was 0.84 (SD=0.21). A limit value of 0.54 ng/ml yielded a sensitivity of 75% and a specificity of 89%. The area under the curve for late cardiac complications was 0.45 (SD= 0.13). CONCLUSION: A cTnI level greater than 0.54 ng/ml appears to be correlated with the occurrence of cardiac complications in the period until discharge, but no value of cTnI is predictive of late cardiac complications occurring in the 1st year after aortic surgery.

Aged↗
PubMed2000

Cytoskeletal abnormalities in chondrocytes with EXT1 and EXT2 mutations.

The EXT genes are a group of putative tumor suppressor genes that previously have been shown to participate in the development of hereditary multiple exostoses (HME), HME-associated and isolated chondrosarcomas. Two HME disease genes, EXT1 and EXT2, have been identified and are expressed ubiquitously. However, the only known effect of mutations in the EXT genes is on chondrocyte function as evidenced by aberrant proliferation of chondrocytes leading to formation of bony, cartilage-capped projections (exostoses). In this study, we have characterized exostosis chondrocytes from three patients with HME (one with EXT1 and two with EXT2 germline mutations) and from one individual with a non-HME, isolated exostosis. At the light microscopic level, exostosis chondrocytes have a stellate appearance with elongated inclusions in the cytoplasm. Confocal and immunofluorescence of in vitro and in vivo chondrocytes showed that these massive accumulations are composed of actin bundled by 1.5-microm repeat cross-bridges of alpha-actinin. Western blot analysis shows that exostosis chondrocytes from two out of three patients aberrantly produce high levels of muscle-specific alpha-actin, whereas beta-actin levels are similar to normal chondrocytes. These findings suggest that mutations in the EXT genes cause abnormal processing of cytoskeleton proteins in chondrocytes.

Actinin↗
PubMed1998

The effect of vitamin B12 deficiency on older veterans and its relationship to health.

OBJECTIVE: To examine the effect of vitamin B12 deficiency on older veterans and its relationship to general health and cognitive impairment. DESIGN: Cross-sectional study. SETTING: Oklahoma City Veterans Affairs Medical Center. PARTICIPANTS: Data for this research were obtained from 303 ambulatory, older veterans who used the outpatient laboratories of the Oklahoma City Department of Veterans Affairs Medical Center. Subjects were included in the study if they were 65 years of age and older and if they had no known diagnosis associated with B12 deficiency. The sample in this study consisted of 301 men and 2 women aged 65 to 89 years. MEASUREMENTS: This study used two separate measurements of vitamin B12 deficiency: (1) a strict definition of B12 deficiency (serum B12 level < laboratory norm) and (2) a broader definition of B12 deficiency (serum B12 level < laboratory norm or laboratory norm < B12 < 300 pg/mL and methyl malonic acid (MMA) or homocysteine (HC) elevated by more than two standard deviations). The laboratory norm is 200 pg/mL. The dependent variables were measures of cognitive impairment and general health. Cognitive impairment was measured using the Folstein Mini-Mental State Examination (MMSE) and general health was measured using the RAND 36-Item Health Survey Version 1.0. The control variables for this study were the subjects' daily alcohol intake, daily intake of a vitamin/mineral supplement, annual income, and level of education. RESULTS/CONCLUSIONS: Nineteen subjects (6%) were vitamin B12-deficient as measured by the strict definition of B12 deficiency (serum B12 level < laboratory norm), and 49 subjects (16%) were vitamin B12-deficient as measured by the broader definition of B12 deficiency (serum B12 level < laboratory norm or laboratory norm < B12 < 300 pg/mL and MMA or HC elevated by more than two standard deviations). Vitamin B12 level decreases as age increases. Of the nine general health outcomes measured by using the RAND 36-Item Health Survey, only bodily pain is associated with vitamin B12 deficiency, and only then when B12 deficiency is measured as serum B12 level < laboratory norm, the strict definition of B12 deficiency. Vitamin B12-deficient subjects experience more bodily pain than those with normal vitamin B12 levels. There is a significant difference between B12-deficient subjects and B12 normal subjects on cognitive impairment, with B12 normal subjects indicating less cognitive impairment, only when B12 deficiency is measured as B12 level < laboratory norm, the strict definition of B12 deficiency. The broader measurement of vitamin B12 deficiency (i.e., serum B12 level < laboratory norm or laboratory norm < B12 < 300 pg/mL and MMA or HC elevated by more than two standard deviations) is not a significant correlate of cognitive impairment and general health.

Aged↗
PubMed1997

Common health problems among minority elders.

This article reviews the primary health problems of African-American, Hispanic-American, Asian/Pacific Islander-American, and Native-American elders. The goal is to familiarize practicing dietitians with the differences in longevity, disease spectrum, and functional status (where data are available) for each of these ethnic groups. These data should be of assistance in making decisions regarding dietary counseling for ethnic elders. It is acknowledged that most data accumulated according to race do not accurately measure ethnicity. The degree of acculturation may vary widely among individuals. Therefore, it is recommended that dietitians solicit clients' perceptions of the factors that may contribute to illness and the barriers to implementing recommended remedies.

Black or African American↗
PubMed1997

Lumbar muscle rhabdomyolysis after abdominal aortic surgery.

Lumbar muscle rhabdomyolysis has been very rarely reported after surgery. The aim of this study was to determine its incidence and main characteristics in a large population undergoing abdominal aortic surgery. Over a 21-mo period, 224 consecutive patients, 209 male and 15 female, mean age 65 +/- 10 yr, underwent abdominal aortic surgery (aortic aneurysm in 142 patients and occlusive aortic degenerative disease in 82 patients). Surgical incision was a midline incision with exaggerated hyperlordosis in 173 patients and a flank incision with a retroperitoneal approach in 51 patients. Postoperative rhabdomyolysis was diagnosed in 20 patients. In these patients, 9 (4%) experienced severe low back pain, and lumbar muscle rhabdomyolysis was confirmed by tomodensitometry (n = 6) or muscle biopsy (n = 3). The remaining 11 patients had lower limb muscle rhabdomyolysis. Rhabdomyolysis occurred after surgery of longer duration, which involved more frequent visceral artery reimplantation, with longer duration of aortic clamping and greater intraoperative bleeding. Lumbar rhabdomyolysis occurred in younger patients who were more frequently obese. On first postoperative day, the mean creatine kinase (CK) value was greater in lumbar rhabdomyolysis than in lower limb rhabdomyolysis (17,082 +/- 15,003 vs 3,313 +/- 3,120 IU/L, P < 0.05). Acute renal failure and postoperative death did not occur in patients with lumbar muscle rhabdomyolysis. Lumbar rhabdomyolysis was not a rare event after abdominal aortic surgery (4%). This syndrome was characterized by postoperative low back pain of unusual severity, which required analgesic therapy, and induced a very high increase in CK with typical findings at tomodensitometry or muscle biopsy but was not associated with postoperative renal failure.

Acute Kidney Injury↗
PubMed1996

T4 phage gene 32 protein as a candidate organizing factor for the deoxyribonucleoside triphosphate synthetase complex.

After T4 bacteriophage infection of Escherichia coli, the enzymes of deoxyribonucleoside triphosphate biosynthesis form a multienzyme complex that we call T4 deoxyribonucleoside triphosphate (dNTP) synthetase. At least eight phage-coded enzymes and two enzymes of host origin are found in this 1.5-mDa complex. The complex may shuttle dNTPs to DNA replication sites, because replication draws from small pools, which are probably highly localized. Several specific protein-protein contacts within the complex are described in this paper. We have studied protein-protein interactions in the complex by immobilizing individual enzymes and identifying radiolabeled T4 proteins that are retained by columns of these respective affinity ligands. Elsewhere we have described interactions involving three T4 enzymes found in the complex. In this paper we describe similar analysis of five more proteins: dihydrofolate reductase, dCTPase-dUTPase, deoxyribonucleoside monophosphokinase, ribonucleotide reductase, and E. coli nucleoside diphosphokinase,. All eight proteins analyzed to date retain single-strand DNA-binding protein (gp32), the product of T4 gene 32. At least one T4 protein, thymidylate synthase, binds directly to gp32, as shown by affinity chromatographic analysis of the two purified proteins. Among its several roles, gp32 stabilizes single-strand template DNA ahead of a replicating DNA polymerase. Our data suggest a model in which dNTP synthetase complexes, probably more than one per growing DNA chain, are drawn to replication forks via their affinity for gp32 and hence are localized so as to produce dNTPs at their sites of utilization, immediately ahead of growing DNA 3' termini.

Bacteriophage T4↗
PubMed1995

Health and nutritional status of old-old African Americans.

This study reports the initial results of a baseline cross-sectional evaluation of the health and nutritional status of 58 old-old African Americans, 74 years of age and older, residing in low income housing complexes in metropolitan Oklahoma City. Although the population had a high overall functional status, cognitive status, and mood, there were a number of nutritional parameters suggestive of nutritional risk. In particular, 20% of subjects had relatively low serum albumin levels, 14% had serum cholesterol levels below 160 mg/dl, and a subset of the population reported low intake during 24 hour dietary recall. The National Center and Caucus on Black Aged report that 60% of African American elders live at or below the poverty level. These study findings suggest that the present cohort of African American elders may be at nutritional risk.

Black or African American↗
PubMed1994

Urinary incontinence in elderly females.

This article reviews recent literature regarding the incidence, causes, and treatment of urinary incontinence in elderly women. Data gathering was based upon a Medline search of the medical literature from 1987 to 1993. Studies that included fifty subjects or more and that were published in a physician-oriented journal were selected for inclusion. The findings indicate that urinary incontinence is a common problem among elderly women and one that can be easily evaluated and treated, at least initially, in any physician's office.

Aged↗
PubMed1993

Genetic heterogeneity of the V3 region of the HIV-1 envelope glycoprotein in Brazil. Brazilian Collaborative AIDS Research Group.

OBJECTIVE: To examine the genetic heterogeneity of the V3 region of HIV-1 gp120 from 22 Brazilian HIV-1 specimens. DESIGN: Genetic heterogeneity was examined by DNA sequencing of the C2 V3 region of the HIV-1 envelope (env) gene from polymerase chain reaction (PCR)-amplified HIV-1 DNA. Deduced amino-acid sequences were compared to determine the extent of amino-acid conservation among the Brazilian specimens. Genetic similarity among and between the Brazilian specimens and other previously published HIV-1 isolates was analyzed by principal co-ordinate and DNA parsimony methods. METHODS: A 282 base pair (bp) region of a 1.5 kilo (k) bp PCR-amplified HIV-1 env fragment was sequenced by a Taq dye-labeled primer cycle sequencing reaction. Nucleotide sequences were used to analyze inter-specimen relationships based on overall nucleotide sequence similarity and DNA parsimony principles. RESULTS: Amino-acid comparison showed that 15 of the 35 (43%) residues of the V3 loop were conserved among the Brazilian specimens. Nine of the 22 (40%) Brazilian specimens contained the North American-European GPGR tetrapeptide motif, while eight (36%) contained the GWGR motif, previously reported in Japanese isolates. Principal co-ordinate analysis demonstrated that 19 of the 20 examined Brazilian HIV-1 specimens were more similar to North American and Haitian isolates than to African isolates. Similar results were also obtained by DNA parsimony analysis. CONCLUSION: The majority of the Brazilian specimens examined are more genetically related to North American and Haitian HIV-1 isolates than to African isolates. This finding and the presence of a GWGR V3 loop motif in some Brazilian isolates may be important for vaccine development.

Acquired Immunodeficiency Syndrome↗
PubMed1993

Problems in diagnosing infections in the elderly.

Elderly individuals often present with altered signs and symptoms to infectious diseases. Altered signs and symptoms may result from underlying illnesses, physiological changes of the elderly, or chemotherapy. Increased awareness of the occurrence of altered signs and symptoms can facilitate determining the medical diagnosis and treatment of the elderly.

Aged↗
PubMed1993

Decisions regarding services for the frail elderly.

The care of the frail elderly will become a progressive challenge in the decades to come. There are presently validated and standardized measures for assessing the frail elderly, as well as a number of options for their care. The challenge for the physician will be the proper selection of assessment instruments and care options.

Activities of Daily Living↗