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Biomedical subjects

N Bauman

Publications and source records attributed to N Bauman.

At least 19 recordsLinked to original sources
PubMed1997

Database diversity assessment: new ideas, concepts, and tools.

We present some new ideas for characterizing and comparing large chemical databases. The comparison of the contents of large databases is not trivial since it implies pairwise comparison of hundreds of thousands of compounds. We have developed methods for categorizing compounds into groups or series based on their ring-system content, using precalculated structure-based hashcodes. Two large databases can then be compared by simply comparing their hashcode tables. Furthermore, the number of distinct ring-system combinations can be used as an indicator of database diversity. We also present an independent technique for diversity assessment called the saturation diversity approach. This method is based on picking as many mutually dissimilar compounds as possible from a database or a subset thereof. We show that both methods yield similar results. Since the two methods measure very different properties, this probably says more about the properties of the databases studied than about the methods.

Benzene Derivatives↗
PubMed1995

Indirect calorimetry in the nutritional management of eating disorders.

The caloric prescription, a key component of the nutritional therapy of anorexia nervosa (AN) and bulimia nervosa (BN), may be empirically prescribed, or based on predicted resting energy expenditure (REE), yet adaptive changes in the metabolic rate may render both methods unreliable. Indirect calorimetry measurement of fasting REE was obtained in 32 patients with AN (n = 21) or BN (n = 11). Predicted REE was calculated according to the Harris-Benedict equation, and empiric caloric prescriptions were made by experienced physicians. In the AN group, mean measured REE was significantly lower than predicted REE (p = .00). The empiric caloric prescription was, as intended, significantly higher than the measured REE, but the two methods correlated significantly (r = .53, p < .05). The predicted REE overestimated caloric needs but was also highly correlated with measured REE (r = .69, p < .001). By regression analysis, measured REE could be calculated from predicted REE as follows: measured REE (Kcal/day) = (1.84 x Harris-Benedict predicted REE) - 1,435. In the BN group, mean measured REE was not significantly different from the empiric caloric prescription (p = .09) but was significantly lower than the Harris-Benedict predicted REE (p = .022). Neither correlated with measured REE in BN. Therefore, in BN indirect calorimetry is the only reliable method for determining caloric needs. In AN indirect calorimetry remains the preferred method, but when not available, we recommend the above equation to determine resting energy requirements.

Adolescent↗
PubMed1991

A method for automatic generation of novel chemical structures and its potential applications to drug discovery.

A novel method for generation of chemical structures of potential pharmaceutical interest is presented. Structures are generated by random combination of known fragments and selected by statistical topological techniques. The power of the method lies in the great profusion of candidates generated together with the extremely high selectivity imposed by the techniques of selection.

Chemistry, Pharmaceutical↗
PubMed1988

An efficient algorithm for sequencing peptides using fast atom bombardment mass spectral data.

An efficient algorithm is described for sequencing peptides from sequence ions appearing in fast atom bombardment (FAB) and FAB tandem mass spectra. The following features are incorporated in the algorithm. The members of the set of sequence ions are represented by all possible combinations of N- and C-terminal fragment ions. From the known N- and C-terminating groups and molecular weight (MW) of the peptide, the sequence ions are mathematically re-expressed as N-terminal residue ions and arranged in ascending order. The peptide sequence is computed, in a stepwise iterative procedure, from the mass differences between the mathematically re-expressed N-terminal residue ions and the predicted peptide subsequences for the neighboring ions of lower mass. These mass differences correspond to combinations of known amino acid residues which have previously been computed and tabulated, based upon the FAB fragmentation rules for peptides. The algorithm was successfully applied to sequence the following peptides from their respective FAB or FAB tandem mass spectrum: decapeptyl (MW 1310), angiotensin II (MW 1045), and two 'unknown' peptides (MW 1227 and 1485, respectively). Two criteria used to predict the correct peptide sequence from among many possibilities are the minimum number of amino acid residues and the maximum fragmentation probability per amino acid residue.

Algorithms↗
PubMed1985

Depletion of complement by light and porphyrin does not depend on sequential activation.

The mechanism of complement depletion from human serum fortified with porphyrin and irradiated with light has been reinvestigated, with the conclusion that it did not depend on the normal sequence of complement activation. Thus, disappearance of the activities of C3, C4, and C5 was not dependent on divalent cations. Purified C3-C7 were labile to porphyrin/light treatment in the absence of other components. The depletion of C4 was not prevented by potent inhibitors of C1 and, unlike the depletion of C4 seen in response to aggregated gamma globulin, was insensitive to change in temperature. Electrophoresis showed an alteration of C3 unlike that caused by cobra venom factor and that light/porphyrin treatment nonspecifically altered many serum proteins.

Complement Activation↗
PubMed1984

Passive transfer of collagen arthritis: studies with affinity-purified anticollagen IgG prepared in rabbits.

Affinity-purified rabbit anticollagen IgG failed to transfer arthritis to rats when it was injected intravenously. Immunofluorescence examination of the joints of the hind paws of recipient rats showed the deposition of rabbit IgG on the articular surfaces; however, C4 or C3 deposition was not detected. In recipient rats injected intravenously with equivalent amounts of rat anticollagen IgG, arthritis occurred within 48 hr; IgG, C4, and C3 could be detected on the articular surface. Rats given Type II collagen intravenously accumulated inflammatory cells in the pleural cavity in response to a subsequent challenge with intrapleural rat anticollagen IgG; with rabbit anticollagen IgG significantly fewer cells accumulated. Rabbit anticollagen IgG did not promote the lysis of Type II collagen coated sheep red blood cells that were incubated with rat serum. In parallel control experiments, lysis of cells occurred when rat serum was added to either sheep cells coated with Type II collagen and incubated with rat anticollagen IgG or sheep cells coated with bovine serum albumin and incubated with rabbit anti-bovine serum albumin. These observations suggest that the failure of rabbit anticollagen IgG to transfer arthritis to rats is, at least in part, due to its inability to activate rat complement.

Animals↗
PubMed1983

Pulsatile tinnitus arising from jugular megabulb deformity: a treatment rationale.

Pulsatile tinnitus is a rare presenting symptom in patients with enlarged jugular bulbs. We will describe three young women presenting with right pulsatile tinnitus associated with a megabulb deformity of the temporal bone. After extensive radiologic and audiologic evaluation, no vascular or bony abnormalities could be identified. All three patients demonstrated pulsatile bruits over the right temple. Pulsatile tinnitus disappeared with ipsilateral jugular compression suggesting flow rather than pressure to be responsible for abnormal auditory symptoms. This observation formed the basis of our treatment recommendations. Because of progressively debilitating pulsatile tinnitus, two patients elected right internal jugular vein ligations under local anesthesia. Both patients were relieved of tinnitus. We conclude that jugular vein ligation can be a safe and effective surgical treatment for pulsatile tinnitus resulting from a jugular megabulb deformity, provided two criteria are met: 1. The presence of an expanding tumor is ruled out. 2. The presence of contralateral venous drainage is established by angiography or brain scan. Anatomic and functional hemodynamic considerations of brain circulation will be emphasized in the discussion of our treatment rationale.

Adult↗
PubMed1982

Effects of iodipamide on human C3 and factor B in vitro.

The effects of iodipamide on C3 and factor B in normal human serum and in purified form have been examined by immunoelectrophoresis and sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). Temperature-dependent changes in immunoelectrophoretic profiles have been observed; however, these are not the same as those obtained after treatment of normal human serum (NHS) with cobra venom factor Naja naja. Analyses of iodipamide-treated NHS and purified C3 and factor B by reducing SDS-PAGE indicate that no macromolecular changes have occurred in C3 and factor B that can be ascribed to proteolysis (i.e., activation). The changes observed in C3 and factor B, including loss of hemolytic activity, appear to be due to direct interactions between iodipamide and C3 and factor B. In the case of factor B, iodipamide treatment at 37 degrees C induces aggregation, which is reversible upon reduction with beta-mercaptoethanol.

Complement Activation↗
PubMed1981

Systematic discovery and evaluation of complement inhibitors.

Methods are presented for an orderly search of a chemical file for complement inhibitors. Compounds are initially examined for intrinsic activity against dilute human components in vitro, using hemolytic assays to detect inhibitors of fluid phase C1, of late components lysis of EAC142, and of CVF-induced passive lysis of AET-treated human erythrocytes. Active compounds are then examined for activity against undiluted serum in vitro. Compounds passing this test are examined for activity in vivo against serum complement and complement-dependent lesions, viz. Forssman vasculitis, the reverse passive Arthus phenomenon, and Forssman shock. Methods are given for quantitation of these lesions.

Animals↗