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Biomedical subjects

M L Connolly

Publications and source records attributed to M L Connolly.

17 recordsLinked to original sources
PubMed1992

Shape distributions of protein topography.

A method is presented for measuring protein surface shape. It is an improvement of an earlier method that intersects a sphere with the solvent-excluded volume of a protein molecule. The new method, called a shape distribution, produces a more sophisticated description of the region of the sphere inside the protein than is provided by simply measuring the region's area or solid angle. This method is applied to the prediction of molecular complexes in three systems: the hemoglobin nonallosteric interface, trypsin and trypsin inhibitor, and heme and apomyoglobin. It does not uniquely predict the correct structure, even though the individual structures are taken from the experimentally determined complex structure. However, it does provide a list of several hundred predicted complexes, one of which is correct, and from which the correct complex might be extracted by a subsequent chemical filter.

Algorithms↗
PubMed1991

Ambulatory surgery and prepared discharges. Effects on orthopedic patients and nursing practice.

Orthopedic medical and nursing practice has changed dramatically partly as a result of three trends: cost containment, technology, and consumer activism. Many orthopedic procedures previously requiring inpatient hospital stays are routinely performed on an outpatient, day-surgery basis. it is imperative that nurses working in the ambulatory surgery environment be diligent in practicing the nursing process to ensure comprehensive patient care. Patients requiring hospitalization for orthopedic procedures now have shorter lengths of stay. The brevity of stay means that a great deal of coordination, education, and referral efforts are necessary before the patient's discharge. Prepared discharge programs, with the nurse assuming the coordinator role, are one way of ensuring that patients are ready to make the transition from the hospital to their postdischarge environment.

Ambulatory Surgical Procedures↗
PubMed1990

Influence of photoperiod and 6-methoxybenzoxazolinone on the reproductive axis of inbred LSH/Ss Lak male hamsters.

Adult male Syrian hamsters of the inbred LSH/Ss Lak strain were maintained under a 14L:10D light cycle until 13 weeks of age. At this point, they were implanted s.c. with elastomer capsules that were either empty or packed with 30-40 mg of 6-methoxybenzoxazolinone (6-MBOA), a compound found naturally in some monocotyledonous plants; half of the animals from each treatment group were then kept in long days (14L:10D) or transferred to short days (9L:15D). Testicular size was measured and blood samples collected from each hamster immediately before capsule implantation and again 2, 4, 6 and 8 weeks later. Within just 2 weeks of exposure to short days the mean plasma levels of LH and FSH had significantly declined, in both the control and 6-MBOA-treated animals, and were basal within 4 weeks. Testicular size closely followed these gonadotrophin changes; within 4-6 weeks the testes from all of the short-day hamsters had completely regressed to a prepubertal size. At the end of the experiment, at Week 8, the animals were killed and various components of the hypothalamo-pituitary-testicular axis were compared between the treatment groups. The pituitary content of FSH and LH, testicular weight, mean serum level of testosterone, but not hypothalamic LHRH content or pituitary gland weight, were considerably lower in the short-day than in the long-day hamsters, regardless of whether or not they had been chronically treated with 6-MBOA.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1987

Thermal expansion of a protein.

The thermal expansion of a protein, metmyoglobin, was investigated by analysis of the refined X-ray crystal structures at 80 and 255-300 K. On heating from 80 to 300 K, the volume occupied by myoglobin increases by approximately 3%. The linear thermal expansion coefficient is estimated to be 115 X 10(-6) K-1. This value is more than twice as large as that of liquid water but less than that of benzene. As the temperature is raised, the internal volume change does not come from the large, atom-sized internal cavities in the structure but from an increase in the small, subatomic free volumes between atoms. The largest expansion occurs in the region of the CD and GH corners; both these regions move away from the center of the protein. The remainder of the expansion results from the lengthening of contacts between segments of secondary structure.

Animals↗
PubMed1986

Computational studies of the interaction of myoglobin and xenon.

Computational studies are used to investigate the energies of xenon binding to myoglobin and to describe pathways through the protein interior for a metmyoglobin-xenon complex. Empirical energy calculations indicate a favorable enthalpic contribution of 0.6 to 4.2 kcal/mol to xenon binding for four experimentally determined xenon sites. These calculated enthalpies help to explain the different xenon occupancies observed experimentally. A fifth site, modeled in place of the iron co-ordinated water molecule in the distal cavity, is also predicted to bind xenon. The largest contribution to the binding energy is from van der Waals' interactions with smaller contributions from polarization and protein strain terms. Ligand trajectory calculations as well as a new geometric algorithm define a connecting network of channel-like pathways through the static protein structure. One or two pathways appear to lead most easily from each major internal cavity to the protein surface. The importance of these channels in protein dynamics and their implications as routes for ligand motion are discussed.

Algorithms↗
PubMed1986

Atomic size packing defects in proteins.

The three-dimensional refined high resolution structures of 20 proteins were examined for the presence of packing defects of atomic size or larger. Of the proteins examined, 12 had no such packing defects, 6 proteins had just 1 packing defect, and 2 proteins had 2 or 3 packing defects. These results confirm earlier studies on smaller samples of proteins which demonstrated that proteins are well packed. The atoms that surround the packing defects are almost always hydrophobic (carbon or sulfur). This study also tabulated the number of internal waters in each protein, which varied from 0 to 28.

Enzymes↗
PubMed1984

The structure of an antigenic determinant in a protein.

The immunogenic and antigenic determinants of a synthetic peptide and the corresponding antigenic determinants in the parent protein have been elucidated. Four determinants have been defined by reactivity of a large panel of antipeptide monoclonal antibodies with short, overlapping peptides (7-28 amino acids), the immunizing peptide (36 amino acids), and the intact parent protein (the influenza virus hemagglutinin, HA). The majority of the antipeptide antibodies that also react strongly with the intact protein recognize one specific nine amino acid sequence. This immunodominant peptide determinant is located in the subunit interface in the HA trimeric structure. The relative inaccessibility of this site implies that antibody binding to the protein is to a more unfolded HA conformation. This antigenic determinant differs from those previously described for the hemagglutinin and clearly demonstrates the ability of synthetic peptides to generate antibodies that interact with regions of the protein not immunogenic or generally accessible when the protein is the immunogen.

Amino Acid Sequence↗
PubMed1983

Solvent-accessible surfaces of proteins and nucleic acids.

A method is presented for analytically calculating a smooth, three-dimensional contour about a molecule. The molecular surface envelope may be drawn on either color raster computer displays or real-time vector computer graphics systems. Molecular areas and volumes may be computed analytically from this surface representation. Unlike most previous computer graphics representations of molecules, which imitate wire models or space-filling plastic spheres, this surface shows only the atoms that are accessible to solvent. This analytical method extends the earlier dot surface numerical algorithm, which has been applied in enzymology, rational drug design, immunology, and understanding DNA base sequence recognition.

Aspartate Carbamoyltransferase↗
PubMed1982

Computer graphics in drug design: molecular modeling of thyroid hormone-prealbumin interactions.

Computer graphics modeling of the thyroxine-prealbumin complex provides a detailed picture of the interactions between thyroxine and prealbumin. A wide variety of thyroid hormone analogue-prealbumin complexes were modeled by calculating the molecular surfaces of the analogues and the prealbumin hormone-binding site. Analogues with high binding affinity were observed to fill more of the hormone-binding site than low-affinity analogues. These surface models described many aspects of the hormone-protein interaction which were not obvious using simple wire models and led us to develop a model which accounts for thyroid hormone-prealbumin structure-activity relationships and ultimately to predict and measure the relative binding affinities of four previously untested thyroid hormone analogues to prealbumin.

Chemical Phenomena↗
PubMed1981

Real-time color graphics in studies of molecular interactions.

Studies of the structures and interactions of large biological molecules require both coordinate data and three-dimensional visualization. Orthodox molecular models often bear a tenuous relationship to the coordinate data. In contrast, computer graphics requires that the display directly and accurately represent the data, and storage of modified configurations and recovery of original structures are simple. Software has been developed that allows real-time display of color line and surface displays of several interacting molecules, while quantitatively monitoring the stereochemistry.

Carboxypeptidases↗
PubMed1981

Distance geometry analysis of the N.M.R. evidence on the solution conformation of bleomycin.

Conformational constraints derived from n.m.r. experiments, X-ray data and the known stereochemistry have been used to investigate by the distance geometry method the range of allowed solution conformations for Cu(II):P-3A (a biosynthetic precursor of bleomycin), Fe(II):bleomycin:carbon monoxide, and Zn(II):bleomycin. The experimental data have been found to be self-consistent and lead to the following observations. 1) Designation of the ligands and the dihedral angles available from vicinal coupling constants are not sufficient to define uniquely the geometry around the metal. 2) When only five bleomycin ligands are invoked (e.g. Cu(II):P-3A or Fe(II):bleomycin:carbon monoxide) there is considerable freedom in the allowed coordination scheme around the metal, but some regions of the molecule have well determined conformation. 3) Introduction of a sixth bleomycin ligand, as in Zn(II):bleomycin, considerably constrains the conformational freedom of the groups coordinated to the zinc. The utility of the distance geometry approach for analysis of data and design of experiments is discussed.

Bleomycin↗
PubMedDate not supplied

Home care of the prostate cryosurgery patient.

1. Through the use of the pathway process, variation in home care of the prostate cryosurgery patient is reduced in caregiver technique and efficiency of care delivery is improved. More importantly, patient outcomes are closely monitored and multidisciplinary continuity of care is promoted. The pathway helps ensure that appropriate resources are initiated and used in appropriate timeframes. 2. A patient version of the critical pathway, written in lay terminology, is given to patients to define their responsibilities in the care process. This method encourages patient participation in care. 3. The purpose of home care is to educate the patient about his disease process and treatment regimen, and encourage him to participate in his treatment and recovery. The prostatic cryosurgery pathway gives him an opportunity to be active in his care.

Cryosurgery↗