PubMed Health⌕ Search

Biomedical subjects

P E Brown

Publications and source records attributed to P E Brown.

At least 19 recordsLinked to original sources
PubMed1997

Association of purified skeletal-muscle AMP deaminase with a histidine-proline-rich-glycoprotein-like molecule.

Denaturation of rabbit skeletal-muscle AMP deaminase in acidic medium followed by chromatography on DEAE-cellulose in 8 M urea atpH 8.0 allows separation of two main peptide components of similar apparent molecular mass (75-80 kDa) that we tentatively assume correspond to two different enzyme subunits. Whereas the amino acid composition of one of the two peptides is in good agreement with that derived from the nucleotide sequence of the known rat and human AMPD1 cDNAs, the second component shows much higher contents of proline, glycine and histidine. N-Terminal sequence analysis of the fragments liberated by limited proteolysis with trypsin of the novel peptide reveals a striking similarity to the fragments produced by plasmin cleavage of the rabbit plasma protein called histidine-proline-rich glycoprotein (HPRG). However, some divergence is observed between the sequence of one of the fragments liberated from AMP deaminase by a more extensive trypsinization and rabbit plasma HPRG in the region containing residues 472-477. A fragment with a blocked N-terminus, which was found among those liberated by proteolysis with pepsin of either whole AMP deaminase or the novel component of the enzyme, shows an amino acid composition quite different from that of the N-terminus of the known subunit of AMP deaminase. By coupling this observation with the detection in freshly prepared AMP deaminase of a low yield of the sequence (LTPTDX) corresponding to that of HPRG N-terminus, it can be deduced that in comparison with HPRG, the putative HPRG-like component of AMP deaminase contains an additional fragment with a blocked N-terminus, which is liberated by a proteolytic process during purification of the enzyme. The implications of the association to rabbit skeletal-muscle AMP deaminase of a HPRG-like protein species are discussed.

AMP Deaminase↗
PubMed1994

Evidence of a species-differentiated regulatory domain within the N-terminal region of skeletal muscle AMP deaminase.

Rabbit skeletal muscle AMP deaminase was submitted to limited proteolysis by trypsin that converts the native 80 kDa enzyme subunit to a stable product of approx. 70 kDa, which, in contrast to the native enzyme, is not sensitive to regulation by ATP at pH 6.5. Tryptic peptide mapping indicates that proteolysis is confined to the N-terminal region of the molecule, identifying in this region of AMP deaminase a non-catalytic, 95 residue regulatory domain that stabilises the binding of ATP to a distant site in the molecule. Protein sequence analysis reveals a marked degree of divergence between rat and rabbit skeletal muscle AMP deaminases in the regions containing residues 7-12 and 51-52, giving molecular basis to the hypothesis of the existence of isoenzymes of AMP deaminase in the mature skeletal muscle of the mammals.

AMP Deaminase↗
PubMed1994

Site and significance of chemically modifiable cysteine residues in glutamate dehydrogenase of Clostridium symbiosum and the use of protection studies to measure coenzyme binding.

Protein chemical studies of NAD(+)-dependent glutamate dehydrogenase (GDH; EC 1.4.1.2) from Clostridium symbiosum indicate only two cysteine residues/subunit, in good agreement with the gene sequence. Experiments with various thiol-modifying reagents reveal that in native clostridial GDH only one of these two cysteines is accessible for reaction. This residue does not react with iodoacetate, iodoacetamide, N-ethylmaleimide or N-phenylmaleimide, but reaction with either p-chloromercuribenzene sulphonate or 5,5'-dithiobis(2-nitrobenzoic acid) causes complete inactivation, preventable by NAD+ or NADH but not by glutamate or 2-oxoglutarate. Protection studies with combinations of substrates show that glutamate enhances protection by NADH, whereas 2-oxoglutarate diminishes it. These studies were also used to determine a dissociation constant (0.69 mM) for the enzyme-NAD+ complex. Similar data for NADH indicated mildly cooperative binding with a Hill coefficient of 1.32. The significance of these results is discussed in the light of the high-resolution crystallographic structure for clostridial GDH and in relation to information for GDH from other sources.

Amino Acid Sequence↗
PubMed1993

The Acute Physiology and Chronic Health Evaluation II classification system is a valid marker for physiologic stress in the critically ill patient.

OBJECTIVE: To compare the Acute Physiology and Chronic Health Evaluation (APACHE II) score with resting energy expenditure obtained from indirect calorimetry to determine whether the APACHE II scoring system is an accurate, objective measure of the degree of critical illness and physiologic stress between groups of patients. DESIGN: Prospective study. SETTING: University hospital, tertiary referral center. PATIENTS: Seventy critically ill patients, consecutively sampled from burn, surgical, and medical intensive care units. INTERVENTIONS: Indirect calorimetric studies were performed on each patient using a metabolic cart. The acute physiologic score component of the APACHE II scoring system was determined at the time of metabolic testing, a mean of 15.9 days after hospital admission. MEASUREMENTS AND MAIN RESULTS: True resting energy expenditure was calculated by adjusting the measured energy expenditure for diet-induced thermogenesis and fever. A predicted resting energy expenditure was calculated for each patient using the Harris-Benedict equation alone, and by using the Harris-Benedict value corrected for previously published metabolic activity factors. To eliminate differences in body composition and size, true resting energy expenditure was divided by weight, body surface area, and Harris-Benedict resting energy expenditure. Results showed no significant correlation between APACHE II scores and either the Harris-Benedict resting energy expenditure or the Harris-Benedict value corrected by metabolic activity factors. However, there was a significant (p < or = .001; r2 = .18 to .20) relationship between increasing APACHE II scores and both increasing measured and true resting energy expenditure. The true resting energy expenditure divided by body surface area, kilogram body weight, and Harris-Benedict predicted value, were all shown to be significantly (p < .01) related to APACHE II score, but showed no better degree of correlation (r2 = .12 to .23) than comparison of APACHE II score with measured or true resting energy expenditure. CONCLUSIONS: The APACHE II classification may be a valid marker of physiologic stress as demonstrated by its statistically significant (although weak) relationship with indirect calorimetric measures of energy expenditure associated with varying degrees of critical illness.

Adolescent↗
PubMed1991

The partial amino acid sequence of the NAD(+)-dependent glutamate dehydrogenase of Clostridium symbiosum: implications for the evolution and structural basis of coenzyme specificity.

The amino acid sequence is reported for CNBr and tryptic peptide fragments of the NAD(+)-dependent glutamate dehydrogenase of Clostridium symbiosum. Together with the N-terminal sequence, these make up about 75% of the total sequence. The sequence shows extensive similarity with that of the NADP(+)-dependent glutamate dehydrogenase of Escherichia coli (52% identical residues out of the 332 compared) allowing confident placing of the peptide fragments within the overall sequence. This demonstrated sequence similarity with the E. coli enzyme, despite different coenzyme specificity, is much greater than the similarity (31% identities) between the GDH's of C. symbiosum and Peptostreptococcus asaccharolyticus, both NAD(+)-linked. The evolutionary implications are discussed. In the 'fingerprint' region of the nucleotide binding fold the sequence Gly X Gly X X Ala is found, rather than Gly X Gly X X Gly. The sequence found here has previously been associated with NADP+ specificity and its finding in a strictly NAD(+)-dependent enzyme requires closer examination of the function of this structural motif.

Amino Acid Sequence↗
PubMed1990

Exacerbation of chronic obstructive pulmonary disease due to hyperinfection with Strongyloides stercoralis.

Pulmonary infection due to the filariform larvae of Strongloides stercoralis may occur in immunocompromised patients residing in endemic areas of the United States. Such infection usually presents as dyspnea with a cough that sometimes results in bloody sputum. Although the chest roentgenogram often reveals a patchy bilateral alveolar infiltrate, acute respiratory distress is unusual. We report a patient who experienced severe exacerbation of his underlying obstructive lung disease that was associated with chest infiltrates and recovery of S stercoralis from his sputum. Although initial improvement was accomplished with Thiobendazole treatment, a re-exacerbation occurred when antiparasitic therapy was completed. The persistence of his infection is correlated to factors that are commonly employed in the treatment of COPD but may be overlooked as predisposing causes of hyperinfection with S stercoralis.

Animals↗
PubMed1987

Merkle cell carcinoma report of a case and possible role for adjuvant radiotherapy.

A case of neuroendocrine (Merkle cell) carcinoma of the skin is described. This uncommon tumor occurred in a 76-year-old female and presented as a small exophytic nodule on the right anterior chest wall. Following primary excision, it was thought to be a basal cell carcinoma. The diagnosis of Merkle cell carcinoma was established only after the tumor had recurred locally and involved ipsilateral axillary lymph nodes. Although local control was achieved with surgery and radiotherapy, the patient died of probable hepatic metastases 18 months after presentation. The Merkle cell tumor is an undifferentiated small cell carcinoma originating in the skin and has distinct ultrastructural characteristics that help to differentiate it from other small cell tumors. The clinicopathologic characteristics of these potentially aggressive neoplasms are reviewed, and treatment is briefly discussed.

Aged↗
PubMed1975

Ambulatory treatment of femoral shaft fractures with cast-brace.

Our early results support use of the cast-brace, early ambulation treatment of both open and closed fractures of the femoral shaft in all adult age groups. We believe initial traction should be used to reduce the fracture and maintain reduction until the fracture is clinically "sticky" to avoid subsequent malalignment in the cast-brace. The method facilitates early rehabilitation of the fractured extremity and the patient with minimal residual disability such as non-union, malunion, chronic infection and joint stiffness, so often associated with other forms of long bone fracture treatment.

Adolescent↗
PubMed1975

Surgical treatment for nonunion of the scaphoid.

Fracture of the scaphoid is the most common injury of the carpal bones. Most scaphoid fractures heal after immobilization. When the fracture does not unite, degenerative arthritic changes and disability may occur. Twenty-four symptomatic nonunions treated surgically were reviewed. Based on presence of union, percent of normal motion, and patients' symptoms, results were rated good in 19 cases and fair in five. Nine of ten patients treated with bone grafting and styloidectomy had union of fractures with good results. All five patients with bone grafting and internal fixation had union. Excision of proximal fragments of more than one third to one half of the scaphoid, and internal fixation alone, had unsatisfactory results. A styloidectomy should excise approximately one half of the radius articulating with the scaphoid. If not enough styloid is excised, osteophytic overgrowth will occur; if too much is excised, the carpus will sublux radially.

Adolescent↗
PubMed1972

The lipid-teichoic acid complex in the cytoplasmic membrane of Streptococcus faecalis N.C.I.B. 8191.

1. A lipid-teichoic acid complex was isolated from Streptococcus faecalis N.C.I.B. 8191. The covalent nature of the linkage between teichoic acid and lipid was established. 2. The complex exhibits macromolecular properties in solution, and ultracentrifugation studies show that these are due to micelle formation. 3. From chemical studies it is concluded that the teichoic acid is a poly(glycerol phosphate) in which some of the glycerol hydroxyl groups possess kojibiosyl [2-O-alpha-d-glucopyranosyl-(1-->2)-alpha-d- glucopyranosyl] substituents, together with d-alanine ester residues. 4. The lipid is 1-kojibiosyl diglyceride, already known as a membrane component of this organism, with probably a phosphatidyl substituent. The phosphatidyl kojibiosyl diglyceride is attached to the teichoic acid through a phosphodiester linkage, and the chain of the teichoic acid contains 28-35 units. 5. Although the complex represents the whole of the membrane teichoic acid in this organism, only about 12% of the membrane glycolipid is associated with teichoic acid. 6. Two phosphatidyl glycolipids, closely resembling that bearing the teichoic acid, were isolated from the lipids of the organism and were partly characterized.

Chromatography, Gas↗