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Biomedical subjects

S Fisher

Publications and source records attributed to S Fisher.

At least 91 records · Page 5Linked to original sources

Preoperative obesity is associated with decreased survival after heart transplantation.

BACKGROUND: It is difficult to assess candidacy of obese patients for heart transplantation because the effect of obesity before heart transplantation on posttransplantation outcome has not been examined. Therefore, the purpose of this study was to examine the impact of both preoperative weight and postoperative weight gain on outcome after heart transplantation. METHODS: The retrospective sample included 193 consecutive patients undergoing transplantation between March 1984 and June 1991 (mean age 47 +/- 14 years, 75% male). Data were gathered from retrospective chart review. Percent ideal body weight was calculated for each patient. Patients were divided into three groups based on pretransplantation percent ideal body weight: < 90% ideal body weight (n = 30), 90% to 110% ideal body weight (n = 79), and > 110% ideal body weight (n = 84). Chi-square, analysis of variance, Kaplan-Meier survival distributions, and the Cox Proportional Hazards Model were used for analyses. RESULTS: Patients > 110% ideal body weight tended to have more coronary artery disease and higher serum triglyceride levels and significantly higher cholesterol levels than patients < 90% ideal body weight. After heart transplantation, no significant differences were found among the three pretransplantation percent ideal body weight groups regarding acute rejection, infection, and allograft arteriopathy. Survival was significantly worse among patients who were overweight before surgery (p = 0.018). A multivariate survival analysis showed that percent ideal body weight was an independent predictor of survival after heart transplantation (p = 0.046). CONCLUSIONS: Despite a similar incidence of infection and rejection after heart transplantation among the three percent ideal body weight groups, obesity before heart transplantation is associated with significantly decreased survival after heart transplantation.

Adolescent↗

Acute renal failure with thrombocytopenia after cryosurgery of the prostate.

We report three cases of transient acute renal failure accompanied by thrombocytopenia all occurring within 48 h of percutaneous transperineal cryoprostatectomy. Renal function spontaneously improved in all three patients, who currently have normal renal function and are voiding without difficulty. No known risk factor or specific etiology for the renal failure could be identified; therefore, we conclude that the renal failure is most likely secondary to the cryosurgery procedure, a common link shared by all three patients. We are currently administering intravenous mannitol before initiation of the freeze and have seen no further episodes of postcryosurgical acute renal failure in > 50 patients with prostate cancer. Because cryosurgery is currently becoming a more pervasive treatment option for localized prostate cancer, we believe it most important to report this heretofore unrecognized potential complication.

Acute Kidney Injury↗

A check on rational drug design: crystal structure of a complex of human immunodeficiency virus type 1 protease with a novel gamma-turn mimetic inhibitor.

We have previously reported (Newlander et al., J. Med. Chem. 1993, 36, 2321-2331) the design of human immunodeficiency virus type 1 (HIV-1) protease inhibitors incorporating C7 mimetics that lock three amino acid residues of a peptide sequence into a gamma-turn. The design of one such compound, SB203238, was based on X-ray structures of reduced amide aspartyl protease inhibitors. It incorporates a gamma-turn mimetic in the P2-P1' position, where the carbonyl of the C7 ring is replaced with an sp3 methylene group yielding a constrained reduced amide. It shows competitive inhibition with Ki = 430 nM at pH 6.0. The three-dimensional structure of SB203238 bound to the active site of HIV-1 protease has been determined at 2.3 A resolution by X-ray diffraction and refined to a crystallographic R-factor (R = sigma magnitude of Fo magnitude of - magnitude of Fc magnitude of /sigma magnitude of Fo magnitude of, where Fo and Fc are the observed and calculated structure factor amplitudes, respectively) of 0.177. The inhibitor lies in an extended conformation in the active site; however, because of the constrained geometry of the C7 ring, it maintains fewer hydrogen bonds with the protein than in most other HIV-1 protease-inhibitor complexes. More importantly, the inhibitor binds to the enzyme differently than predicted in its design, by binding with the P2-P1' alpha-carbon atoms shifted by approximately one-half a residue toward the N-terminus from their presumed positions. This study illustrates the importance of structural information in an approach to rational drug design.

Amino Acid Sequence↗

Severe, irreversible renal failure after ifosfamide treatment. A clinicopathologic report of two patients.

BACKGROUND: Chronic renal failure has been described only rarely in patients treated with the alkylating agent ifosfamide, which is known to cause renal tubular dysfunction and acute renal failure, and the associated histopathologic features have not been well characterized. METHODS: This report describes the clinical course and renal histopathologic features in two patients in whom irreversible renal failure occurred requiring permanent dialysis after treatment with ifosfamide. RESULTS: Irreversible renal failure developed in a 60-year-old man with malignant fibrohistiocytoma, requiring chronic dialysis within several months after he received two cycles of ifosfamide in a cumulative dose of 28 g/m2. The second patient, a 53-year-old man with osteogenic sarcoma, received two cycles of ifosfamide with a cumulative dose of 26 g/m2, after initial therapy with cisplatin and doxorubicin. His renal function worsened over the next 11 months, at which time permanent dialysis was initiated. In neither patient were other causes of renal failure apparent. Renal biopsies in both patients showed diffuse tubular epithelial damage with degenerative and regenerative epithelial changes, diffuse interstitial fibrosis, and arterial and arteriolar sclerosis. CONCLUSIONS: Irreversible severe renal failure, which appears due to nephrotoxic damage of renal tubular epithelium and/or the renal microvasculature may develop after treatment with ifosfamide. Neither large cumulative doses of ifosfamide nor prior cisplatin treatment are necessary for this toxicity to occur. Because a rising serum creatinine may develop months after completion of treatment with ifosfamide, renal function should be monitored closely both during and after ifosfamide treatment.

Antineoplastic Agents, Alkylating↗

High-resolution comparative mapping of the proximal region of the mouse X chromosome.

The murine homologues of the loci for McLeod syndrome (XK), Dent's disease (CICN5), and synaptophysin (SYP) have been mapped to the proximal region of the mouse X chromosome and positioned with respect to other conserved loci in this region using a total of 948 progeny from two separate Mus musculus x Mus spretus backcrosses. In the mouse, the order of loci and evolutionary breakpoints (EB) has been established as centromere-(DXWas70, DXHXF34h)-EB-Clcn5-(Syp, DXMit55, DXMit26)-Tfe3-Gata1-EB-Xk-Cybb-telomere. In the proximal region of the human X chromosome short arm, the position of evolutionary breakpoints with respect to key loci has been established as DMD-EB-XK-PFC-EB-GATA1-C1CN5-EB-DXS1272E-ALAS2-E B-DXF34-centromere. These data have enabled us to construct a high-resolution genetic map for the approximately 3-cM interval between DXWas70 and Cybb on the mouse X chromosome, which encompasses 10 loci. This detailed map demonstrates the power of high-resolution genetic mapping in the mouse as a means of determining locus order in a small chromosomal region and of providing an accurate framework for the construction of physical maps.

Animals↗

Synthesis and biological evaluation of radioiodinated phospholipid ether analogs.

Previous work has shown that radioiodinated phospholipid ether analogs with the iodine-125 substituted on the meta position of the aromatic ring readily localized in a variety of animal tumors. In an effort to ascertain the importance of such meta substitution, three phospholipid ether analogs with the iodine-125 in the para position were synthesized for evaluation as potential tumor-localizing imaging agents. 12-(p-Iodophenyl)dodecyl phosphocholine, 1-O-[12-(p-iodophenyl)dodecyl]-1,3-propanediol-3-phosphocholine, and 1-O-[12-(p-iodophenyl)dodecyl]-2-O-methyl-3-rac-glycerophosphocholine were synthesized and labeled with iodine-125 via an isotope exchange procedure. Similar to previous results with the meta substituted analogs, tissue distribution studies with the three para analogs demonstrated tumor localization and retention of radioactivity at 24 h after i.v. injection. In all three cases, the para isomers showed greater tumor avidity than the meta isomers and clearance of the radiotracer from the tumor was much slower than the clearance from nontarget tissue. 12-(p-Iodophenyl)dodecyl phosphocholine afforded the greatest tumor-to-nontarget tissue ratio. For example, the tumor-to-blood and tumor-to-liver ratios at 24 h were 10.96 and 1.85, respectively. As a result of such selective tumor retention, it was possible to clearly delineate the tumor using gamma-camera scintigraphy.

Animals↗

The effects of self-hypnosis on quality of life following coronary artery bypass surgery: preliminary results of a prospective, randomized trial.

The effects of complementary techniques and alternative medicine on allopathic therapies is generating much interest and research. To properly evaluate these techniques, well controlled studies are needed to corroborate the findings espoused by individuals practicing complementary medicine therapies. To this end, we evaluated the role of one of these therapies, self-hypnosis relaxation techniques, in a prospective, randomized trial to study its effects on quality of life after coronary artery bypass surgery. Subjects were randomized to a control group or a study group. Study group patients were taught self-hypnosis relaxation techniques the night prior to surgery. The control group received no such treatment. Patients then underwent routine cardiac management and care. The main endpoint of our study was quality of life, assessed by the Profile of Moods Scale. Results demonstrated that patients undergoing self-hypnosis the night prior to coronary artery bypass surgery were significantly more relaxed than the control group (p = 0.0317). Trends toward improvement were also noted in depression, anger, and fatigue. This study demonstrates the beneficial effects of self-hypnosis relaxation techniques on coronary surgery. This study also identifies endpoints and a study design that can be used to assess complementary medicine therapies. Results of this preliminary investigation are encouraging and demonstrate a need for further well-controlled studies.

Affect↗

Ventilatory arrest after a fluid challenge in a neonate receiving s.c. morphine.

S.c. infusions of morphine have been advocated for postoperative analgesia in children, but experience with this technique is limited. We report a case in which an s.c. infusion of morphine given after operation to a neonate failed to provide acceptable analgesia until the child had been adequately rehydrated. However, restoration of peripheral perfusion with a fluid challenge was followed by sudden ventilatory arrest which required resuscitation and naloxone infusion. This report emphasizes the dangers of giving morphine by a peripheral route in the dehydrated or hypovolaemic infant.

Analgesics, Opioid↗

Oxygen radical scavengers are protective against indomethacin-induced intestinal ulceration in the rat.

Nonsteroidal antiinflammatory drugs (NSAIDs) are widely used and may cause small intestinal inflammation and damage. Reactive oxygen metabolites are involved in various gastrointestinal inflammatory processes, but there is little information about their role in small intestinal mucosal damage induced by NSAIDs. We studied the effect of the oxygen radical scavengers superoxide dismutase (SOD), catalase (CAT), and allopurinol (ALLO) on indomethacin (INDO)-induced intestinal ulceration in the rat. Ulceration was produced by s.c. injection of 30 mg/kg of INDO 30 min after refeeding 24 h-fasted rats. Total ulcer area was measured 24 h after INDO administration. Study groups each consisted of eight animals which received either i.p. CAT, SOD, or both together, at a dosage of 5,000 U/kg each. All drugs were divided into five doses, given once an hour over a 4-h period, starting at the time of INDO injection. Another group received 100 mg/kg ALLO in two doses. Total ulcer area was reduced by SOD from 228 +/- 12 (sq mm, mean +/- SEM) to 153 +/- 12 (p < 0.001), by CAT to 179 +/- 13 (p < 0.01), and by both together to 95 +/- 5 (p < 0.0001). ALLO administration reduced the total ulcer area to 176 +/- 7 (p < 0.003). The protective effect of oxyradical scavengers supports the hypothesis that oxygen radicals are involved in the pathogenesis of INDO-induced small intestinal ulceration in the rat.

Allopurinol↗

Regulation of Gax homeobox gene transcription by a combination of positive factors including myocyte-specific enhancer factor 2.

Homeobox-containing genes play an essential role in basic processes during embryogenesis and development, but little is known about the regulation of their expression. To elucidate regulatory networks that govern homeobox gene expression, we defined the core promoter of the mouse Gax homeobox gene and characterized its interactions with cellular proteins. Transient transfection experiments revealed Gax promoter activity in several cell types. Deletion analysis defined a 138-bp minimal promoter fragment between positions -125 and +13 relative to the transcription initiation site. Mutagenesis and protein-DNA binding assays suggested that at least three positive factors interact with this fragment and are required for transcriptional activity. One of these factors, HRF-1, recognizes a cis element consisting of an inverted palindromic motif. A second factor is Sp1, that binds to a G/C-rich element. The third is the MADS box factor referred to as MEF2 or RSRF. Mutations in the MEF2/RSRF site had the greatest effect on transcription in cell types that expressed the highest levels of endogenous MEF2 activity. Conversely, overexpression of MEF2A transactivated the Gax promoter more efficiently in cells lacking endogenous MEF2. These data provide evidence for a direct transcriptional link between members of the MADS and homeobox families of transcription factors.

Amino Acid Sequence↗

Mapping the X chromosome breakpoint in two papillary renal cell carcinoma cell lines with a t(X;1)(p11.2;q21.2) and the first report of a female case.

A t(X;1)(p11.2;q21.2) has been reported in cases of papillary renal cell tumors arising in males. In this study two cell lines derived from this tumor type have been used to indicate the breakpoint region on the X chromosome. Both cell lines have the translocation in addition to other rearrangements and one is derived from the first female case to be reported with the t(X;1)(p11.2;q21.2). Fluorescence in situ hybridization (FISH) has been used to position YACs belonging to contigs in the Xp11.2 region relative to the breakpoint. When considered together with detailed mapping information from the Xp11.2 region the position of the breakpoint in both cell lines was suggested as follows: Xpter-->Xp11.23-OATL1-GATA1-WAS-TFE3-SY P-t(X;1)-DXS255-CLCN5-DXS146-OATL2- Xp11.22-->Xcen. The breakpoint was determined to lie in an uncloned region between SYP and a YAC called FTDM/1 which extends 1 Mb distal to DXS255. These results are contrary to the conclusion from previous FISH studies that the breakpoint was near the OATL2 locus, but are consistent with, and considerably refine, the position that had been established by molecular analysis.

Carcinoma, Papillary↗

Placebo washout is not a meaningful part of antidepressant drug trials.

Most trials testing the effectiveness of psychotropic drugs begin with a placebo washout phase. Hypothetically this technique rids studies of placebo responders before randomization of subjects to drug and placebo groups. In theory, this lowers the level of response to placebo in the study and magnifies the superiority of the response to medication. An analysis of 10 years of research literature demonstrates that the washout technique does not do what it was designed to do in antidepressant studies. Within placebo or drug groups neither measures of depression nor dropouts were affected by including a preliminary washout in the design. The findings are consistent with the two other studies that have addressed this issue.

Antidepressive Agents↗

Bacillaene, a novel inhibitor of procaryotic protein synthesis produced by Bacillus subtilis: production, taxonomy, isolation, physico-chemical characterization and biological activity.

Bacillaene, a novel polyene antibiotic, was discovered and isolated from fermentation broths of a strain of Bacillus subtilis. The novel antibiotic has a nominal molecular weight of 580 and an empirical formula of C35H48O7. Bacillaene is active against a broad spectrum of bacteria in agar-plate diffusion assays. Studies in vitro indicate that the antibiotic inhibits prokaryotic protein synthesis but not eukaryotic protein synthesis. Cell survival studies performed with strains of Escherichia coli indicate that the antibiotic is a bacteriostatic agent.

Anti-Bacterial Agents↗

Postmarketing surveillance by patient self-monitoring: preliminary data for sertraline versus fluoxetine.

BACKGROUND: There have been no published postmarketing reports comparing sertraline with another serotonin selective reuptake inhibitor (SSRI) in large-sample, parallel groups. As part of an ongoing postmarketing surveillance study, this paper presents preliminary data for a number of adverse clinical events reported by outpatients being treated with either fluoxetine or sertraline. METHOD: Using a well-validated method developed to signal possible adverse drug reactions, data were collected on 1577 fluoxetine-treated and 1209 sertraline-treated patients who filled a prescription for either of the two targeted drugs. Pharmacists gave these patients an announcement, part of which served as an entry form, that described the purpose and details of the study. Volunteers (highly selective) were requested to report during the next month via a toll-free telephone interview "any new or unusual symptoms or unexpected improvements" in their health since starting the designated medication. RESULTS: Almost 1 (31.4%) of every 3 sertraline-treated patients called at least once to report one or more adverse clinical events compared with only about 1 (19.7%) of every 5 fluoxetine-treated patients. Most of the reported adverse clinical events--but not all--are well-known adverse drug reactions that seem common to SSRIs. Adverse clinical events reported more frequently by sertraline-treated patients included urinary, sexual, psychological, neurologic, gastrointestinal, and dermatological complaints. Drug discontinuation was also reported more frequently by sertraline-treated patients. Fluoxetine-treated patients reported an increased frequency of weight gain and anger or aggression. CONCLUSION: These data indicate that many adverse reactions known to be induced by fluoxetine are being reported with even greater frequency by sertraline-treated patients. Possible interpretations of these differences are discussed.

1-Naphthylamine↗

An orally bioavailable HIV-1 protease inhibitor containing an imidazole-derived peptide bond replacement: crystallographic and pharmacokinetic analysis.

(2R,4S,5S,1'S)-2-Phenylmethyl-4-hydroxy-5-(tert-butoxycarbonyl) amino-6-phenylhexanoyl-N-(1'-imidazo-2-yl)-2'-methylpropanamide (compound 2) is a tripeptide analogue inhibitor of HIV-1 protease in which a C-terminal imidazole substituent constitutes an isoelectronic, structural mimic of a carboxamide group. Compound 2 is a potent inhibitor of the protease (K(i) = 18 nM) and inhibits HIV-1 acute infectivity of CD4+ T-lymphocytes (IC50 = 570 nM). Crystallographic analysis of an HIV-1 protease-compound 2 complex demonstrates that the nitrogen atoms of the imidazole ring assume the same hydrogen-bonding interactions with the protease as amide linkages in other peptide analogue inhibitors. The sole substitution of the C-terminal carboxamide of a hydroxyethylene-containing tripeptide analogue with an imidazole group imparts greatly improved pharmacokinetic and oral bioavailability properties on the compound compared to its carboxamide-containing homologue (compound 1). While the oral bioavailability of compound 1 in rats was negligible, compound 2 displayed oral bioavailabilities of 30% and 14%, respectively, in rats and monkeys.

Administration, Oral↗

Antibodies against linear and conformational epitopes of the human papillomavirus (HPV) type 16 E6 and E7 oncoproteins in sera of cervical cancer patients.

Sera obtained from 137 cervical cancer patients were analysed for the presence of antibodies to the human papillomavirus (HPV) type 16 proteins E6 and E7 by the aid of different assays, i.e. ELISA using as antigen either synthetic peptides or the complete E7 protein and radio-immunoprecipitation (RIPA) which uses the viral protein made by in vitro transcription/translation. In agreement with previous reports, reactivity to the E7 protein was found more frequently than to the E6 protein (31.4% vs. 16.8%) when the sera were assayed by peptide-based ELISA. In contrast, when RIPA was employed, reactivity to either protein was obtained at similar frequency (38.7% vs 46.7%). When the protein was denatured prior to immuno-precipitation the reactivity was lost in all sera tested for E6-specific antibodies but only in a few samples in the E7-RIPA. Therefore it was concluded that the increased sensitivity of the E6-RIPA as compared to the E6 peptide-ELISA is due to the detection of antibodies to conformational epitopes which are presented by the in vitro product but not by the synthetic peptides. Eighty-two sera from healthy donors were tested by HPV 16E6- and E7-RIPA and also by ELISA using the HPV 16E7 protein which was produced in the fission yeast Schizosaccharomyces pombe. One sample reacted each in the E6- and E7-RIPA indicating a high specificity of these assays. The E7 protein-ELISA proved to be less sensitive for the detection of antibodies in cervical cancer patients' sera (22.6% positive) as compared to peptide-based ELISA or RIPA.

Adolescent↗

Induction of hyperphosphorylation and activation of the p56lck protein tyrosine kinase by phenylarsine oxide, a phosphotyrosine phosphatase inhibitor.

The T cell protein tyrosine kinase p56lck is implicated in thymic development and mitogenic activation of T lymphocytes, and is itself regulated by reversible tyrosine phosphorylation. When phenylarsine oxide (PAO), a membrane-permeable inhibitor of phosphotyrosine phosphatases, was added to Jurkat T leukemia or LSTRA thymoma cells, the phosphate content of p56lck increased rapidly. The sites of increased phosphorylation were mapped to Tyr-192, Tyr-394 and Tyr-505. Hyperphosphorylated p56lck displayed retarded mobility on SDS gels, unaltered or marginally increased cytoskeletal association, and its catalytic activity changed in a biphasic manner; during the first 10-20 min of PAO-treatment the activity increased and then it declined to very low values within 1-2 hr. Our data suggest that p56lck contains both positive and negative regulatory sites which are constantly dephosphorylated at an unexpectedly high rate by cellular phosphotyrosine phosphatases.

Animals↗