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Biomedical subjects

A Healy

Publications and source records attributed to A Healy.

At least 19 recordsLinked to original sources
PubMed1998

Inhibitors of the chymotrypsin-like activity of proteasome based on di- and tri-peptidyl alpha-keto aldehydes (glyoxals).

A series of peptidyl alpha-keto aldehydes (glyoxals) have been synthesised as putative inhibitors of the chymotryptic-like activity of proteasome. The most potent peptides, Cbz-Leu-Leu-Tyr-COCHO and Bz-Leu-Leu-Leu-COCHO, function as slow-binding reversible inhibitors, exhibiting final Ki values of approximately 3.0 nM. These are among the lowest values so far reported for (tri)peptide-based aldehyde-related inhibitors.

Chymotrypsin↗
PubMed1998

Evaluation and long-term treatment of aberrant behavior displayed by young children with disabilities.

We trained parents to conduct functional analyses and functional communication treatment for 28 young children with developmental disabilities who displayed aberrant behavior. Of this sample, 22 parents conducted treatment for at least 3 months and 11 for 1 year. We conducted single-case analyses of the results of assessment and treatment. The functional analysis identified social functions (positive and negative reinforcement) for 86% (24 of 28) of the children. Treatment resulted in a pre/post decrease in aberrant behavior averaging 87% across the range of children, with the greatest decrease occurring at 3 months. Appropriate social responding increased, on average, by 69% across the range of children. Decreases in aberrant behavior were demonstrated in all children, and all except one child displayed increased social behavior during treatment. On a measure of parent-rated treatment acceptability, ranging from 1 (not at all acceptable) to 7 (very acceptable), the average overall acceptability was 6.35.

Behavior Therapy↗
PubMed1997

Isolation and identification of further peptides in the diafiltration retentate of the water-soluble fraction of Cheddar cheese.

Several peptides were isolated from the diafiltration retentate, prepared using 10 kDa membranes, of the water-soluble extract from a commercial mature Cheddar cheese and identified by amino acid sequencing and mass spectrometry. Most of the peptides were from the N-terminal half of the beta-casein, but peptides from alpha s1- and alpha s2-caseins were also identified; the extract also contained alpha-lactalbumin. Identified peptides showed the important role played by lactococcal cell envelope proteinases in the degradation of primary proteolytic products from alpha s1- and beta-caseins, produced by chymosin and plasmin respectively. Plasmin seemed to be involved in the hydrolysation of alpha s2-casein. Several phosphopeptides were identified and the action of phosphatase on these peptides was evident.

Amino Acid Sequence↗
PubMed1997

Specificity of an extracellular proteinase from Brevibacterium linens ATCC 9174 on bovine beta-casein.

The specificity of the extracellular proteinase from Brevibacterium linens ATCC 9174 on bovine beta-casein was studied. Hydrolysis was monitored over time by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (PAGE) and urea-PAGE. The major pH 4.6-soluble peptides were isolated by high-performance liquid chromatography and identified by N-terminal amino acid sequencing and mass spectrometry. The major sites of hydrolysis were Ser-18-Ser-19, Glu-20-Glu-21, Gln-56-Ser-57, Gln-72-Asn-73, Leu-77-Thr-78, Ala-101-Met-102, Phe-119-Thr-120, Leu-139-Leu-140, Ser-142-Trp-143, His-145-Gln-146, Gln-167-Ser-168, Gln-175-Lys-176, Tyr-180-Pro-181, and Phe-190-Leu-191. The proteinase had a broad specificity for the amino acid residues present at the P1 and P'1 positions but showed a preference for hydrophobic residues at the P2, P3, P4, P'2, P'3, and P'4 positions.

Amino Acid Sequence↗
PubMed1996

Specificity of an extracellular proteinase from Brevibacterium linens ATCC 9174 on bovine alpha s1-casein.

The specificity of the extracellular proteinase from Brevibacterium linens ATCC 9174 on bovine alpha s1-casein was studied. Hydrolysis was monitored over time by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (PAGE) and urea-PAGE. The major pH 4.6-soluble peptides were isolated by high-performance liquid chromatography and identified by N-terminal amino acid sequencing and mass spectrometry. The time course of peptide formation indicated that His-8-Gln-9, Ser-161-Gly-162, and either Gln-172-Tyr-173 or Phe-23-Phe-24 were the first, second, and third bonds cleaved, respectively. Other cleavage sites included Asn-19-Leu-20, Phe-32-Gly-33, Tyr-104-Lys-105, Leu-142-Ala-143, Phe-150-Arg-151, Gln-152-Phe-153, Leu-169-Gly-170, and Thr-171-Gln-172. The proteinase had a broad specificity for the amino acid residues at the P1 and P'1 positions but showed a preference for hydrophobic residues at the P2, P3, P4, P'2, P'3, and P'4 positions.

Amino Acid Sequence↗
PubMed1996

Aerobic power and supramaximal endurance of competitive figure skaters.

OBJECTIVE HYPOTHESES: 1) figure skaters possess average aerobic power; 2) on-ice training would not improve aerobic power of supramaximal endurance; 3) off-ice training plus on-ice training would improve aerobic power and supramaximal endurance. EXPERIMENTAL DESIGN: This was a prospective, controlled study in which we monitored ice skaters before, during and after two different 10 week training programs. SETTING: Athletes training for competition sanctioned by the United States Figure Skating Association. PARTICIPANTS: 15 figure skaters (12 females) enrolled at an ice skating academy were randomly placed in two study groups. INTERVENTIONS: Grp 1 maintained on-ice training and Grp 2 supplemented on-ice with cycle ergometer training. MEASURES: Maximum O2 consumption (VO2peak) during cycle ergometer exercise, anaerobic threshold, HR, supramaximal exercise time and the lactate (LACT) response to exercise. RESULTS: (*, p < 0.05), Grp 1: VO2peak, pre = 44.2 +/- 2.2 ml/[kg.min], post = 41.4 +/- 1.6 ml/[kg.min]; VO2peak% (% predicted), pre = 100 +/- 5%, post = 92 +/- 4%; anaerobic threshold as % VO2peak (AT%), pre = 74 +/- 3%, post = 73 +/- 3%; Supramaximal Time, pre = 0.87 +/- 0.12 min, post = 0.94 +/- 0.12 min; lower LACT occurred at VO2peak and supramaximal exercise following on-ice training. Grp 2: VO2peak, pre = 50.7 +/- 3.6 ml/[kg.min], post = 55.9 +/- 3.3 ml/[kg.min]*; VO2peak%, pre = 110 +/- 7%, post = 121 +/- 6%*; AT%, pre = 80 +/- 2%, post = 83 +/- 2%*; Supramaximal Time, pre = 1.31 +/- 0.18 min, post = 2.69 +/- 0.66 min*; lower LACT occurred at 50%, 75% and VO2peak following training. CONCLUSIONS: 1) Grp 1 plus Grp 2 had average aerobic power (VO2peak = 105 +/- 3% of predicted) prior to the study; 2) on-ice training did not affect aerobic power or supramaximal endurance, while off-ice training improved these parameters; 3) the LACT response detected training adaptations.

Adaptation, Physiological↗
PubMed1995

Water-soluble peptides in Cheddar cheese: isolation and identification of peptides in the diafiltration retentate of the water-soluble fraction.

The water-soluble extract of Cheddar cheese was fractionated by diafiltration using 10 kDa cut-off membranes. Peptides were isolated from the diafiltrate retentate by chromatography on DEAE-cellulose with a linear NaCl gradient in 50 mM-Tris-HCl. pH 8.6, and reversed-phase HPLC or electroblotting from urea-PAGE gels. Peptides were identified by determining N-terminal amino acid sequences and mass spectrometry. Most (45) of the total 51 peptides identified in the diafiltrate retentate originated from beta-casein, especially from a short region in the N-terminal half of the molecule. Only six peptides originated from alpha s1-casein; beta-lactoglobulin was also identified in the retentate. The origin of most of these peptides could be explained on the basis of known specificities of lactococcal cell envelope proteinases.

Amino Acid Sequence↗
PubMed1994

Proteolysis of bovine alpha s2-casein by chymosin.

Proteolysis of bovine alpha s2-casein by chymosin (E. C. 3.4.23.4) in solution in 100 mM Na phosphate buffer, pH 6.5, at 30 degrees C was studied by reversed-phase (RP)-HPLC and urea-polyacrylamide gel electrophoresis (PAGE). Chymosin hydrolyzed alpha s2-casein in solution to eight peptides detectable by urea-PAGE. Peptides soluble in acetate buffer, pH 4.6, were isolated by RP-HPLC on a C18 column using an acetonitrile/water gradient and identified from their N-terminal amino acid sequence. The chymosin cleavage sites were at the bonds Phe88-Tyr89, Tyr95-Leu96, Gln97-Tyr98, Tyr98-Leu99, Phe163-Leu164, Phe174-Ala175 and Tyr179-Leu180. Chymosin cleavage sites were restricted to the hydrophobic regions of the molecule. The bond-type in alpha s2-casein cleaved by chymosin was in agreement with that found to be susceptible to chymosin in other caseins. The primary site of chymosin action on alpha s2-casein appeared to be at Phe88-Tyr89.

Amino Acid Sequence↗
PubMed1993

Peptide glyoxals: a novel class of inhibitor for serine and cysteine proteinases.

A series of novel synthetic dipeptides, containing a C-terminal glyoxal grouping (-COCHO), have been tested as inhibitors against typical members of the serine- and cysteine-proteinase families. For example, the sequences benzyloxycarbonyl (Cbz)-Pro-Phe-CHO (I) and Cbz-Phe-Ala-CHO (II), which fulfil the known primary and secondary specificity requirements of chymotrypsin and cathepsin B respectively, have been found to be potent reversible inhibitors of their respective target proteinase. Thus I was found to inhibit chymotrypsin with a Ki of approximately 0.8 microM, whereas II exhibits a Ki of approximately 80 nm against cathepsin B. These Ki values are some 10-fold and 3-fold lower than those reported for the corresponding peptide-aldehyde inhibitors of chymotrypsin and cathepsin B upon which the peptidyl-glyoxals were fashioned. Unexpectedly, the sequence Cbz-Pro-Ala-CHO, which was designed to inhibit elastase-like proteinases, exhibited no inhibitory activity towards porcine pancreatic elastase, even when used at concentrations as high as 200 microM.

Animals↗
PubMed1993

Proteolytic specificity of chymosin on bovine alpha s1-casein.

The proteolytic specificity of chymosin (EC 3.4.23.4) on bovine alpha s1-casein at 30 degrees C in phosphate buffer, pH 6.5 and at pH 5.2 in the presence of 5% (w/v) NaCl was investigated. Peptides (pH 4.6-soluble) were isolated by reversed-phase HPLC and identified from their amino acid sequence; the identity of some peptides was confirmed by mass spectrometry and/or amino acid composition. The small peptides produced at pH 6.5 were Arg1-Phe23, Phe24-Phe28, Phe24-Leu40(?), Phe150-Phe153, Phe150-Leu156, Tyr154-Tyr159, Tyr154-Trp164, Asp157-Trp164 and Tyr165-Trp199. The same peptides, except Tyr154-Trp164, were produced at pH 5.2 in the presence of NaCl and, in addition, the peptides Arg1-Leu11, Phe24-Phe32, Lys102-Leu142, Ala143-Leu149 and Tyr165-Phe179. The rates of production of individual peptides differed under the two conditions studied but Arg1-Phe23 and Tyr165-Trp199 were the first and second peptides produced under both conditions. Pathways are proposed to interpret the proteolysis of alpha s1-casein in solution under the conditions of this study.

Amino Acid Sequence↗
PubMed1992

Participation by pediatricians in early intervention: impetus from Public Law 99-457.

Part H of the Individuals with Disabilities Education Act (originally enacted as Public Law 99-457) requires that participating states phase in a system of early intervention services by 1993. By recognizing the importance of good health in the development of infants and toddlers, Congress acknowledged the key role of medical care providers in a comprehensive program for young children with or at risk for developmental delay or dysfunction. National and state surveys of pediatricians suggest limited but growing awareness of this legislation and uncertainty about how they might participate effectively. A chief concern relates to mechanisms of payment for developmental screening and assessment as well as time-demands for participation in interdisciplinary team activities. The American Academy of Pediatrics and its state chapters are responding to requests for information with educational seminars and print materials. Pediatricians can enhance the quality of community support services for children with special needs by participating in planning efforts and by coordinating health care with other aspects of early intervention. Other professionals and parents are looking to pediatricians for leadership and willing participation in the implementation of PL 99-457.

Child↗