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Biomedical subjects

M Goodman

Publications and source records attributed to M Goodman.

At least 91 records · Page 5Linked to original sources
PubMed1999

Efficacy of jejunogram after jejunostomy insertion.

The era of managed care has spawned a national debate over the allocation of health care resources. We hypothesized that routine postjejunostomy jejunogram rarely provides additional clinical information or changes patient management and, therefore, is unwarranted. We retrospectively reviewed the charts of 128 consecutive patients undergoing feeding jejunostomy tube insertion between January 1995 and December 1996. All patients had postinsertion jejunograms. Eighty-five (66%) of the jejunograms were performed after operative insertion of the jejunostomy, and 43 (33%) were performed after percutaneous reinsertion of a previously placed jejunostomy. Data extracted from the charts include age, sex, indication for jejunogram, length of time prior jejunostomy was in place at time of reinsertion, and results of jejunogram. There were no patients (0%) with misplaced jejunostomy or extravasation of dye, as noted on jejunogram. There were no management changes implemented as a result of jejunogram readings (P < <0.05). The use of routine jejunogram after operative insertion or reinsertion of a prior jejunostomy that has become dislodged or occluded does not alter patient management, incurs unnecessary costs, and, therefore, is unwarranted.

Adolescent↗
PubMed1999

Use of three-dimensional microscopy with multiple oblique illumination in evaluating cytopathology preparations.

OBJECTIVE: To analyze whether the use of multiple oblique illumination (MOI), in contrast to axial illumination (AI), improves imagery in bright field microscopy. Specimens containing thick cell clusters, such as cervical Pap smears, are often misread because of out-of-focus cell clusters. We hypothesized that visualization of these specimens with MOI would enhance this information as compared with AI. STUDY DESIGN: Micrometer images and Pap smears were analyzed in focus, and 8 and 40 microns out of focus by MOI and AI. All fields were captured to a remote computer, histograms were constructed, and mean light intensity was calculated. Mathematical formulation was used to define the histogram distribution of the micrometer images. Statistical analysis was performed using one-way ANOVA and Newman-Keuls test. RESULTS: K(focus) was improved (P < .01) and at 20 and 40 microns out of focus, mean light intensities were greater (P < .003, P < .05, respectively) with MOI as compared to AI. CONCLUSION: MOI improves out-of-focus information by increasing light penetration through the specimen and enhancing contrast and resolution.

Female↗
PubMed1998

Conformational analyses of somatostatin-related cyclic hexapeptides containing peptoid residues.

We report the conformational analysis by 1H NMR in DMSO and computer simulations involving distance geometry and molecular dynamics simulations of a series of peptoid analogues of the cyclic hexapeptide c[Phe11-Pro6-Phe7-d-Trp8-Lys9-Thr10] (1). The proline residue in compound 1 is replaced with the peptoid residues N-benzylglycine (Nphe) (compound 2), N-(S)-alpha-methylbenzylglycine [(S)-beta-MeNphe] (compound 3), and N-(R)-alpha-methylbenzylglycine [(R)-beta-MeNphe] (compound 4). The peptoid analogues 2 and 4 exhibit potent binding activities to the hsst2 receptor, while the binding affinities to the hsst5 and to the hsst3 receptors are reduced compared to that of the parent compound 1. Compound 3 shows reduced binding activities to the hsst2, hsst3, and hsst5 receptors compared to compound 1. The results of in vivo assays indicate that these compounds inhibit the growth hormone release but do not affect the insulin release. These peptoid-containing analogues show two sets of NMR signals corresponding to cis and trans conformations of the peptide bond between Phe11 and Nxaa6. We demonstrate that the backbone conformation and the orientation of the relevant side chains of compound 1 are maintained in the cis isomers of the peptoid analogues which adopt a type VI beta-turn centered around residues 11 and 6 and a type II' beta-turn with d-Trp in the i+1 position. The enhanced selectivity of the peptoid-containing analogues compared to compound 1 and the results of the conformational analysis suggest that the presence of a conformationally constrained hydrophobic group in position 6 in complementary topology to the Phe11 side chain enhances selective binding to the hsst2 receptor.

Computer Simulation↗
PubMed1998

Design, synthesis, and biological activities of potent and selective somatostatin analogues incorporating novel peptoid residues.

We report the synthesis, bioactivity, and structure-activity relationship studies of compounds related to the Merck cyclic hexapeptide c[Pro6-Phe7-d-Trp8-Lys9-Thr10-Phe11], L-363,301 (the numbering in the sequence refers to the position of the residues in native somatostatin). The Pro residue in this compound is replaced with arylalkyl peptoid residues. We present a novel approach utilizing beta-methyl chiral substitutions to constrain the peptoid side-chain conformation. Our studies led to molecules which show potent binding and increased selectivity to the hsst2 receptor (weaker binding to the hsst3 and hsst5 receptors compared to L-363, 301). In vivo, these peptoid analogues selectively inhibit the release of growth hormone but have no effect on the inhibition of insulin. The biological assays which include binding to five recombinant human somatostatin receptors carried out in two independent laboratories and in vivo inhibition of growth hormone and insulin provide insight into the relationship between structure and biological activity of somatostatin analogues. Our results have important implications for the study of other peptide hormones and neurotransmitters.

Animals↗
PubMed1998

Synthesis and biological activity of a novel methylamine-bridged enkephalin analogue (MABE): a new route to cyclic peptides and peptidomimetics.

The synthesis and biological activity of a methylamine-bridged enkephalin analogue (MABE) is presented. The key step in the synthesis of the target compound involves the ring opening of Cbz-d-serine beta-lactone with Boc-Phe-NHCH2CH2NHCH3. Further synthetic elaboration of the resulting building block yielded compound 1 (MABE, Tyr-c[(NbetaCH3)-D-A2pr-Gly-Phe-NHCH2CH2-], where A2pr is a 2,3-diaminopropionic acid residue). Utilizing a combination of NMR and molecular modeling, the structure-biological activity relationships for compound 1 were studied. Using an in vitro isolated receptor assay, MABE was found to have affinities for isolated mu delta, and kappa opioid receptors of 1.6, 2.1, and 340 nM, respectively. By an in vivo thermal escape assay, MABE was found to have an ED50 of 0.027 microg in the rat when administered intrathecally. This effect was reversed by naloxone. By comparison, DAMGO, morphine, and DPDPE were found to yield ED50 values of 0.14, 2.4, and 54 microg, respectively, in the same assay.

Analgesics, Opioid↗
PubMed1998

Poor mental development in patients with tuberous sclerosis complex: clinical risk factors.

OBJECTIVE: To identify clinical risk factors for poor mental development among patients with tuberous sclerosis complex (TSC). DESIGN: Case-control analysis of a clinic population. SETTING: Specialty clinic in a hospital. PATIENTS: One hundred six patients with TSC consecutively seen between January 1984 and December 1995 at the Child Neurology Clinic of the Children's Memorial Health Institute in Warsaw, Poland. STUDY VARIABLES: Seizure type, age at seizure onset, sex, and history of diphtheria, tetanus, and pertussis immunization. MAIN OUTCOME MEASURE: Moderate to profound developmental delays. RESULTS: Seizure type (ie, infantile spasms) was the only analyzed risk factor that showed a consistent and independent association with poor mental development (adjusted odds ratio, 3.0; 95% confidence interval, 1.1-8.4; P =.03). Age at seizure onset, which initially showed a significant association with poor mental development, was no longer significantly associated after adjustment for seizure type (adjusted odds ratio, 1.6; P = .43). Neither sex (odds ratio, 1.1; P = .96) nor history of diphtheria, tetanus, and pertussis immunization (odds ratio, 1.0; P = .80) showed evidence of being a risk factor for poor mental development among patients with TSC. CONCLUSIONS: Infantile spasms, as the type of seizure on initial examination, is a significant risk factor for poor mental development in patients with TSC. Age at time of first seizure is not an independent risk factor but reflects the early ages at which these patients are seen with infantile spasms. Neither sex nor history of diphtheria, tetanus, and pertussis immunization is a risk factor for the subsequent development of poor mental development among patients with TSC.

Age of Onset↗
PubMed1998

Bilateral nasolacrimal duct obstruction managed with endoscopic techniques.

We present 3 cases of bilateral acquired nasolacrimal duct obstruction secondary to Wegener granulomatosis, sarcoidosis, and chronic lymphocytic leukemia. In all cases significant paranasal sinus and intranasal disease coincided with bilateral nasolacrimal duct obstruction. Surgical treatment of the nasolacrimal duct obstruction with dacryocystorhinostomy was more successful if the paranasal sinus disease was also treated. Nontraumatic bilateral nasolacrimal duct obstruction heralds unusual underlying systemic diseases, and coexisting paranasal sinus disease should be suspected. The simultaneous surgical treatment of both lacrimal and paranasal sinus disease through an endoscopic approach is advocated.

Adult↗
PubMed1998

Collagen mimetics.

Collagen peptidomimetics have been synthesized as an alternative to natural collagen. The incorporation of unnatural residues such as peptoids in the collagen sequences can demonstrate potent and specific biological activity and enhance the biostability against enzymatic degradation. Furthermore, the use of achiral peptoids simplifies synthetic strategies by reducing racemization problems. The peptoid residue N-isobutylglycine (Nleu) has been successfully incorporated into a series of collagen mimetics composed of Gly-Pro-Nleu, Gly-Nleu-Pro, and Gly-Nleu-Nleu. The discovery of template-assembled collagen mimetics and metal binding ability has laid the foundation for new opportunities in the design of novel collagen mimetic complexes. The review summarizes the synthesis and integrated biophysical analyses of the structures of these collagen mimetics. Solid phase segment condensation techniques have been utilized for the synthesis of the single chain and template-assembled analogues. The characterization of the collagen-like structures has been established by temperature-dependent optical rotation measurements. CD, NMR spectroscopy, and molecular modelling simulations.

Circular Dichroism↗
PubMed1998

X-ray structures of new dipeptide taste ligands.

The molecular basis of sweet taste was investigated by carrying out the crystal state conformational analysis by X-ray diffraction of the following dipeptide taste ligands: N-3,3-dimethylbutyl-aspartylphenylalanine methyl ester, I (N-DMB-Asp-Phe-OMe), its sodium salt (N-DMB-Asp-Phe-ONa), II, aspartyl-D-2-aminobutyric acid-(S)-alpha-ethylbenzylamide, III (Asp-D-Abu-(S)-alpha-ethylbenzylamide), aspartyl-N'-((2,2,5,5-tetramethylcyclopentanyl)-carbonyl)-(R)- 1,1-diamino-ethane, IV (Asp-(R)-gAla-TMCP), and aspartyl-D-valine-(R)-alpha-methoxymethylbenzyl amide, V (Asp-D-Val-(R)-alpha-methoxymethylbenzylamide). With the exception of the sodium salt II, all compounds are sweet-tasting, showing in some cases considerable potency enhancement with respect to sucrose. The results of this study confirm the earlier model that an 'L-shape' molecular array is essential for eliciting sweet taste for dipeptide-like ligands. In addition, it was established that (i) substitution of the N-terminal group does not inhibit sweet taste, if its zwitterionic character is maintained; (ii) a hydrophobic group located between the stem and the base of the L-shape could be responsible for sweetness potency enhancement, as found in I, III and IV; in fact, the extraordinary potency of the N-alkylated analogue I would support a model with an additional hydrophobic binding domain above the base of the 'L'; (iii) removal of the methyl ester at the C-terminus of compound I with the salt formation gives rise to the tasteless compound II; (iv) for the first time all possible side-chain conformers (g-, g+ and t) for the N-substituted aspartyl residue were observed; and (v) a retro-inverso modification, incorporated at position 2 of the dipeptide chain, confers greater flexibility to the molecule, as demonstrated by the contemporary presence of six conformationally distinct independent molecules in the unit cell and yet sweet taste properties are maintained, as found in IV.

Computer Simulation↗
PubMed1998

Toward a phylogenetic classification of Primates based on DNA evidence complemented by fossil evidence.

A highly resolved primate cladogram based on DNA evidence is congruent with extant and fossil osteological evidence. A provisional primate classification based on this cladogram and the time scale provided by fossils and the model of local molecular clocks has all named taxa represent clades and assigns the same taxonomic rank to those clades of roughly equivalent age. Order Primates divides into Strepsirhini and Haplorhini. Strepsirhines divide into Lemuriformes and Loriformes, whereas haplorhines divide into Tarsiiformes and Anthropoidea. Within Anthropoidea when equivalent ranks are used for divisions within Platyrrhini and Catarrhini, Homininae divides into Hylobatini (common and siamang gibbon) and Hominini, and the latter divides into Pongina for Pongo (orangutans) and Hominina for Gorilla and Homo. Homo itself divides into the subgenera H. (Homo) for humans and H. (Pan) for chimpanzees and bonobos. The differences between this provisional age related phylogenetic classification and current primate taxonomies are discussed.

Animals↗
PubMed1998

Duration of antimicrobial prophylaxis in vascular surgery.

BACKGROUND: This randomized clinical trial compares the incidence of wound infection after vascular surgery in patients who received prophylaxis using the same antibiotic as either a single-dose or a multiple-dose regimen (until the lines/drain tubes were removed, but not for more than 5 days). METHODS: Each of the 302 patients who entered the study received ticarcillin 3.0 g/clavulanate 0.1 g (Timentin) intravenously immediately after the induction of anesthesia. Patients randomized to the multiple-dose group received an average of 14.3 doses (range 9 to 20). RESULTS: The incidence of wound infections was 18% (28 of 153) for patients in the single-dose group and 10% (15 of 149) for patients in the multiple-dose group (P = 0.04; relative risk estimate = 2.00, 95% confidence interval = -1.02 to 3.92). CONCLUSIONS: A multiple-dose antibiotic regimen, rather than single-dose therapy, provides optimal prophylaxis against wound infection for patients undergoing vascular surgery.

Aged↗
PubMed1998

Analysis of the value of empiric vancomycin administration in febrile neutropenia occurring after autologous peripheral blood stem cell transplants.

We conducted a retrospective review of 125 patients undergoing high-dose therapy and stem cell rescue in order to evaluate the incidence of documented infection and the utility of the administration of vancomycin empirically. All patients received prophylactic oral quinolone therapy. Because neutropenia in this setting is relatively brief, 21 patients never manifested fever, and no patient died of infection. Of the remaining 104 patients, positive blood cultures were obtained in only 10, nine with a gram stain positive and one with a gram stain negative organism. Sixty-two patients without any evidence of gram positive infection received vancomycin according to the existing algorithm for care of neutropenic fevers. In this population of patients, empiric administration of vancomycin for neutropenic fevers without culture documentation appears to be unnecessary, could be discontinued safely and at substantial cost savings, and might slow the appearance of vancomycin-resistant organisms.

Adult↗
PubMed1998

Interleukin-2 and leukemia.

Leukemia has been treated with chemotherapy for the past 40 years with only moderate success. A growing body of evidence suggests that by augmenting the immune system more effective results may be obtained. This is highlighted by T cell reinfusions resulting in durable remissions in patients with chronic myelogenous leukemia who have relapsed after an allogeneic transplant. Interleukin-2 is the primary growth factor for T lymphocytes and is a stimulator of natural killer cell activity. It has now been shown that a limited number of otherwise refractory leukemias can be effectively treated with interleukin-2. However, there remains a lack of correlation between the biologic and clinical effects of interleukin-2. The clinical activity of interleukin-2 appears to be greatest in myeloid leukemias. A variety of dose schedules and routes of administration make it difficult to determine if interleukin-2 given to patients in clinical remission is of benefit. Large randomized studies are necessary to explore the role of interleukin-2 in leukemia.

Acute Disease↗
PubMed1998

Interleukin-2 therapy for advanced chronic myeloid leukemia.

Chronic myeloid leukemia (CML) is usually treated with either alpha-interferon or hydrea. Median survival is 6 years. Eventually, in most CML patients, the disease evolves to blast phase with clinical and morphologic characteristics of an acute leukemia. This phase is commonly associated with systemic symptoms and the appearance of new cytogenetic abnormalities. Therapy for this phase is of limited value, resulting in a mean survival of 4 months. We describe four consecutive patients seen at our clinic with advanced stage CML (three blast, one accelerated phase) who were treated with interleukin-2 (Proleukin). The mean survival in these patients was 22 months (range 9-35 months) and two are still alive 25 and 35 months after the start of therapy. One patient had a complete cytogenetic response and another a partial response. Toxicity was minimal and no patient had to discontinue therapy because of it.

Adjuvants, Immunologic↗