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Biomedical subjects

R B Jones

Publications and source records attributed to R B Jones.

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

Optic disc and retinal microvasculopathy after high-dose chemotherapy and autologous hematopoietic progenitor cell support.

The purpose of this study was to prospectively evaluate the retinal and optic nerve changes in patients undergoing high-dose chemotherapy (HDC) followed by autologous hematopoietic progenitor cell support (AHPCS). One hundred and forty patients undergoing HDC and AHPCS underwent extensive pre- and post-transplant ophthalmologic evaluations for development of retinal microvascular complications. One hundred and ten patients received high-dose cyclophosphamide, cisplatin and BCNU; thirty received identical doses of cyclophosphamide and cisplatin, but received paclitaxel instead of BCNU. Thirty-four patients (24%) had retinal findings of either cotton wool spots (CWS) (n = 20) or retinal hemorrhages (n = 18) during follow-up, which ranged from 1 to 12 months. Ten (7%) of these patients, all of whom received BCNU, showed ocular toxicity characterized by CWS 1 to 4 months post transplant (n = 10); optic disc edema (n = 3); and variable vision loss associated with the onset of BCNU-induced pulmonary toxicity. Retinal and optic disc microvascular complications may occur after high-dose chemotherapy followed by AHPCS. The association of ischemic retinal lesions and/or optic disc edema with BCNU-induced pulmonary toxicity and the lack of ocular toxicity in patients that did not receive BCNU may suggest that BCNU is the etiologic agent.

Adult↗
PubMed1999

Early T-maze behaviour and subsequent growth in commercial broiler flocks.

Two batches of 2000 mixed-sex broiler chicks were obtained, one in summer and one in winter. Each flock was housed on the floor at a commercial farm. At 2 or 3 d of age, the latencies to escape from a T-maze were measured in 1044 and 1180 chicks in the summer and winter flocks, respectively. Chicks were assigned to high (HP), moderate (MP) or low (LP) performance categories if their escape latencies were below 40 s, between 40 to 90 s, or above 90 s, respectively. Ninety male and 90 female chicks from each of the 3 categories were weighed when they were 3 d old. The birds then remained undisturbed, apart from routine maintenance, until similar numbers were weighed at 49 d of age. Some birds may have been weighed at both ages. Body weights were higher in males than females and higher in the winter than summer flock at 3 d of age. Significant main effects of chick category as well as gender and season were found at 49 d of age. There were no significant interactions. As expected, 49-d body weights were higher in males than females and in the flock reared in winter than in summer. 5. HP chicks (those that showed rapid escape from the T-maze at 3 d) were also significantly heavier at 49 d than their LP counterparts, with MP chicks occupying an intermediate position. This suggests that early performance in a T-maze test is positively associated with subsequent growth. Furthermore, this relationship was apparent in each of the 2 flocks. Given this positive association, we suggest that this simple, rapid and non-invasive behavioural test could be a useful selection criterion for future breeding programmes.

Aging↗
PubMed1999

Treating Japanese quail with vitamin C does not facilitate their capture by the experimenter.

1. Vitamin C supplementation reduces fear of novel situations and of people. The present study examined its effects on the ease of capture of male Japanese quail by the experimenter. 2. At 20 d of age, quail received either vitamin C (ascorbyl-2-polyphosphate, APP, 1 g L-ascorbic acid/l) solution or untreated drinking water (UDW) for 24 h before they were mixed in 2 groups of 40 (20 APP + 20 UDW. All the birds in 1 group were caught individually by an unsighted experimenter whereas a sighted catcher captured the others. The bird's identity was noted each time. This capture/recapture procedure was repeated 6 times for each group (12 capture trials per bird) and an overall capture rank across all 12 trials was assigned to each bird. 3. Regardless of whether the catcher was sighted or unsighted, the mean ranks of neither APP nor UDW quail differed significantly from the value expected by chance. Neither were there any linear trends in the effects of repeated testing. Thus, prior treatment with vitamin C neither facilitated nor hindered capture. 4. Body weights were similar in both treatment groups and there were no significant intra-individual correlations between body weight and capture rank. 5. Highly significant tendencies were found for individual birds to be caught at similar stages of each capture trial regardless of treatment or test situation. This finding sounds a cautionary note for all studies involving putatively random sampling of a population.

Animals↗
PubMed1999

A phase-II study of trovafloxacin for the treatment of Chlamydia trachomatis infections.

BACKGROUND: Chlamydia trachomatis can cause an insidious, asymptomatic infection in both men and women. Trovafloxacin, a fluoronaphthyridone antibiotic related to the fluoroquinolones, has broad antibacterial activity that encompasses C. trachomatis. GOAL OF STUDY: We designed a phase-II study to determine the efficacy and safety of trovafloxacin for chlamydial infections. STUDY DESIGN: Four once-daily dosing regimens were used: 200 mg for 7 days, 200 mg for 5 days, 100 mg for 7 days, and 50 mg for 7 days. RESULTS: Sixty-four men and 66 women were enrolled. Of the 73 bacteriologically evaluable patients, 20 received 200 mg for 7 days, 18 received 200 mg for 5 days, 14 received 100 mg for 7 days, and 21 received 50 mg for 7 days. Bacteriologic failure occurred in 1 patient (5%) in the 200-mg 7-day group, 2 patients (14%) in the 100-mg group, and 1 patient (5%) in the 50-mg group. No clinical failures were noted among the 30 C. trachomatis infected men with nongonococcal urethritis, although 1 patient had only improved at the final visit. Safety data were available from 119 patients. Of 86 patients receiving the three highest dosing regimens, 17 (20%) had at least one adverse event, judged treatment-related in only 9 (10 %). Of 33 patients receiving the lowest dose, 5 (15%) had an adverse event, three (9%) of which were considered treatment related. No adverse event was severe. CONCLUSION: In doses ranging from 200 mg to 50 mg daily for a week and 200 mg daily for 5 days, trovafloxacin appears to be effective for chlamydial infections and is well tolerated.

Adult↗
PubMed1999

Parental consent to publicity.

The problems presented by the use of named child patients and their medical histories in television, radio and newspapers is discussed. It is suggested that it is not acceptable to regard this as comparable to their participation in non-therapeutic research, and that no one, not even the parent has the authority to give consent to such use.

Child↗
PubMed1999

Acute encephalopathy: a new toxicity associated with high-dose paclitaxel.

The purpose of this study was to describe acute encephalopathy as a new toxicity associated with paclitaxel, when it is delivered at high doses (> or =600 mg/m2) with stem cell support. A total of 129 patients, included in clinical trials of paclitaxel-containing high-dose chemotherapy, were analyzed. A total of 114 patients received paclitaxel at a dose of > or =600 mg/m2. Six patients presented acute encephalopathy starting between 7 and 23 days after paclitaxel treatment; two of them had received prior whole-brain irradiation. Paclitaxel was given alone (one patient), with cyclophosphamide and cisplatin (two patients), and with cyclophosphamide and cisplatin plus 1,3-bis(2-chloroethyl)-1-nitrosourea (three patients). Central nervous system toxicity consisted of rapid obtundation and coma (five patients) and severe confusional picture with paranoid ideations (one patient). Brain magnetic resonance imaging showed diffuse white matter atrophy (one patient) or multiple small infarcts (one patient), or it was normal (four patients). Other complementary tests, including cerebrospinal fluid analysis and electroencephalography, were nondiagnostic. An effect from concomitant psychotropic medications or from other organ toxicities was excluded in all patients. Three patients recovered after 8-15 days, either spontaneously (two patients) or after high-dose steroids (one patient). Three patients died of irreversible coma. Necropsy, performed in two patients, showed generalized white matter atrophy and multiple brain parenchymal infarcts, respectively. No pharmacodynamic correlation between the occurrence of encephalopathy and a pharmacokinetic parameter of paclitaxel could be identified. Paclitaxel-containing high-dose chemotherapy can cause severe acute encephalopathy. An aggravating effect from prior brain irradiation or concurrent 1,3-bis(2-chloroethyl)-1-nitrosourea seems possible.

Antineoplastic Agents, Alkylating↗
PubMed1999

Nonpredictable pharmacokinetic behavior of high-dose cyclophosphamide in combination with cisplatin and 1,3-bis(2-chloroethyl)-1-nitrosourea.

Our objective was to assess whether the total area under the curve (AUC) of high-dose cyclophosphamide (CPA), combined with cisplatin and 1,3-bis(2-chloroethyl)-1-nitrosourea, could be predicted from its AUC on the first day of treatment. We reviewed the AUC of CPA in 470 patients who underwent pharmacokinetic monitoring of the drug. All patients received the same high-dose regimen of CPA, cisplatin, and 1,3-bis(2-chloroethyl)-1-nitrosourea (STAMP-I) with identical antiemetic support. Subsequently, patients who experienced a toxic death, relapsed after high-dose chemotherapy, or remained relapse-free at a minimum follow-up of 1 year after high-dose chemotherapy were analyzed for a correlation between the total AUC of CPA and both relapse-free survival and toxic death. The AUC of CPA decreased from day 1 to day 2 in most patients. However, its changes from day 2 to day 3 varied significantly. Neither the value of AUC on day 1 nor its decreasing trend from day 2 to day 3 could predict the AUC on day 3 and the total AUC. Our pharmacodynamic analysis in 335 patients failed to show a correlation between the total AUC of CPA and either toxic death or relapse-free survival. The significant intersubject variability in the AUC of CPA makes the final AUC of the drug unpredictable from an initial measurement on day 1. Thus, in this combination, measurement of levels of parent CPA, with the objective of real-time therapeutic monitoring of this drug, is not informative.

Analysis of Variance↗
PubMed1999

Phase II trial of high-dose chemotherapy with autologous stem cell transplant for stage IV breast cancer with minimal metastatic disease.

The purpose of this study was to assess the efficacy of high-dose chemotherapy (HDC) with autologous stem cell transplant in stage IV breast cancer patients with minimal metastases. Eligible patients had (a) disease that could be resected en bloc and/or irradiated with curative intent using a single field and could, thus, be rendered as having no evidence of disease (NED); and/or (b) <5% bone marrow involvement. From September 1991 to August 1997, 40 consecutive patients were prospectively entered on the study. Pre-HDC local treatment consisted of surgery (n = 31) and radiotherapy (XRT; n = 3). All patients received HDC with cyclophosphamide, cisplatin, and 1,3-bis(2-chloroethyl)-1-nitrosourea and autologous stem cell transplant, with or without CD34 selection. Following HDC, 22 patients received XRT. Four patients died of treatment-related complications. Eighteen patients developed grade 3 nonhematological toxicities (15 lung, 2 cardiomyopathy, and 1 optic neuritis), which resolved with therapy. Within a median follow-up of 49 (15-91) months, 14 patients had relapsed. Twenty-five patients (62.5%) were alive, and 22 patients (55%) were alive and free of disease. Median event-free and overall survivals were 43 and 77 months, respectively. In the subset of patients with one metastatic site, 17 of 24 (68%) remained relapse free. Grade 2 tumors, a single metastatic site, and delivery of XRT were favorable predictors of relapse-free survival in univariate but not multivariate analyses. Inclusion of HDC, as described, in the multimodal treatment of stage IV breast cancer patients with minimal metastases is promising. These results warrant prospective randomized trials with a HDC-containing arm in this patient population.

Adult↗
PubMed1999

A predictive model for relapse in high-risk primary breast cancer patients treated with high-dose chemotherapy and autologous stem-cell transplant.

High-dose chemotherapy (HDCT) is currently under evaluation for high-risk primary breast cancer (HRPBC), defined by extensive axillary nodal involvement or inflammatory breast carcinoma. Phase II studies of HDCT for HRPBC show that 30-40% of patients eventually relapse. We retrospectively reviewed 176 patients enrolled in clinical trials of HDCT for HRPBC at the University of Colorado and analyzed 23 potential predictive variables for relapse. All of the patients received the same regimen, with cyclophosphamide, cisplatin, and BCNU. Nine patients who experienced a toxic death were excluded from this analysis. The resulting predictive model was subsequently tested in an independent patient set treated at Duke University with the same HDCT regimen. Nodal ratio (number of involved nodes:number of sampled nodes), tumor size, grade, stage, estrogen receptor, progesterone receptor, and clinical inflammatory breast carcinoma correlated with risk of relapse. Nodal ratio, tumor size, and the combined estrogen receptor/progesterone receptor status were independent predictors. A scoring system using those three variables determines the risk of relapse, with a sensitivity and specificity of 60 and 90%, respectively, and a positive and negative predictive value of 65 and 88%, respectively. The differences in relapse-free survival and overall survival between high- and low-score patients were highly significant (P<0.000001). This model was subsequently validated in the Duke patient set. This model can identify two subgroups of HRPBC patients with low (12%) and high (65%) risk for recurrence after HDCT. Future research that tests new therapies will focus on those patients with a high score.

Adult↗
PubMed1998

The glycine box: a determinant of specificity for fibroblast growth factor.

Acidic fibroblast growth factor (FGF-1), keratinocyte growth factor (FGF-7), and FGF-10 are homologues with distinct specificity. In the presence of heparin, FGF-1 binds and activates in vitro all FGFR subtypes, while FGF-7 exhibits absolute specificity for the IIIb splice variant of FGFR2. FGF-10 exhibits a similar specificity but also binds the FGFR1IIIb isoform. Neither FGF-7 nor FGF-10 will bind to IIIc isoforms of FGFR. Molecular models of FGF, heparin, and the FGFR ectodomain suggested that sequences between beta-strands 10 and 12 of FGF may be important for the interaction of FGF with the heparin-FGFR ectodomain duplex. Site-directed mutants of FGF-7 and FGF-10 were prepared to test whether this domain might underlie failure of FGF-7 and FGF-10 to bind to the FGFRIIIc isoforms. Constructions with substitution of FGF-1 sequences spanning the entire C-terminus encoded in exon 3 or only C-terminal sequences spanning beta-strands 10 through 12 conferred ability on FGF-7 to bind to and activate FGFRIIIc without a significant loss in binding to or activation of FGFR2IIIb. A series of twelve different substitutions of shorter segments of FGF-1 sequences into the C-terminal portion of FGF-7 or FGF-10 revealed that substitution of GSCKRG for GIPVRG or the tri-peptide sequence KKN for NQK just N-terminal to it conferred dual activities on both the FGF-7 and FGF-10 backbones. The results suggest that the combined sequence domain, which we call the FGF glycine box (G-box), is a major determinant for the specificity of the binding of FGF to heparan sulfate-FGFR duplexes.

Amino Acid Sequence↗
PubMed1998

Effect of 1,1-dimethyl-2-[2-morpholinophenyl]guanidine fumarate on pancreatic islet function.

The modality of the insulinotropic action of 1,1-dimethyl-2-[2-morpholinophenyl]guanidine fumarate (BTS 67 582), a new antidiabetic agent, was investigated in rat pancreatic islets. At a 0.1 mM concentration, which was sufficient to cause a close-to-maximal secretory response, BTS 67 582 failed to affect the utilization and oxidation of exogenous D-glucose, but slightly augmented 14CO2 production from islets prelabelled with either L-[U-14C]glutamine or [U-14C]palmitate. BTS 67 582 (0.1 mM) also failed to affect biosynthetic activity in islets incubated with L-[4-3H]phenylalanine. It augmented insulin release from islets incubated for 90 min in the absence or presence of D-glucose (2.8 to 16.7 mM), this coinciding with stimulation of 45Ca net uptake. In perifused islets deprived of extracellular D-glucose for 45 min, BTS 67 582 (0.1 mM) decreased 86Rb outflow from prelabelled islets, but failed to increase 45Ca efflux and insulin release. In the presence of D-glucose (7.0 mM), BTS 67 582, whilst failing to decrease 86Rb+ outflow, provoked rapid, sustained and rapidly reversible increases of both 45Ca2+ efflux and insulin output. The latter increases were attenuated, but not totally suppressed, in the absence of extracellular Ca2+. BTS 67 582 (0.1 mM) suppressed the inhibitory action of diazoxide (0.25 mM) upon glucose-stimulated insulin release, but nevertheless augmented insulin output from islets incubated in the presence of 90 mM K+. These findings support the view that the insulinotropic action of BTS 67 582 is mainly attributable to the inactivation of ATP-sensitive K+ channels. An intracellular redistribution of Ca2+ ions may also participate, however, to the islet functional response to BTS 67 582.

Animals↗
PubMed1998

Daily oral grepafloxacin vs. twice daily oral doxycycline in the treatment of Chlamydia trachomatis endocervical infection.

OBJECTIVE: To compare the efficacy and safety of a 7-day course of treatment with oral grepafloxacin, 400 mg once daily, and oral doxycycline, 100 mg twice daily, in patients with chlamydial cervicitis. METHODS: Women aged 18 years or older attending 17 sexually transmitted disease clinics in the United States who had clinical signs of mucopurulent cervicitis or who had a recent positive culture or nonculture test for Chlamydia trachomatis or who had contact with a male partner with a positive culture for C. trachomatis were enrolled into this randomized, double-blind, active-controlled clinical study. The diagnosis of chlamydial cervicitis was based on culture for C. trachomatis. Patients were randomized to receive a 7-day course of treatment with either oral grepafloxacin, 400 mg once daily, or oral doxycycline, 100 mg twice daily. Response to therapy was assessed 3-8 days and 21-28 days after completion of treatment. The primary measure of efficacy was eradication of C. trachomatis at the 21-28 day follow-up visit. Clinical success, defined as improvement or complete resolution of the signs and symptoms of cervicitis, was a secondary measure of efficacy. RESULTS: Of the 451 female patients enrolled, 228 received grepafloxacin and 223 received doxycycline. In all, 154/451 (35%) patients were evaluable at the 21-28 day follow-up (81 who received grepafloxacin and 73 who received doxycycline). Microbiologic and clinical success rates demonstrated the equivalence of the two treatments. The C. trachomatis eradication rates were 96.3% (78/81) and 98.6% (72/73) for patients receiving grepafloxacin or doxycycline, respectively. The two study drugs were also equivalent in resolving clinical signs and symptoms, with clinical success rates of 88.9% (64/72) and 89.5% (51/57) for patients treated with grepafloxacin and doxycycline, respectively. Both drugs were well tolerated, with 47% of patients receiving grepafloxacin and 46% of patients receiving doxycycline experiencing drug-related adverse events, none of which was serious. CONCLUSIONS: Seven days of treatment with oral grepafloxacin, 400 mg once daily, was as effective as 7 days of treatment with oral doxycycline, 100 mg twice daily, in patients with cervicitis caused by C. trachomatis. Both agents were well tolerated and had comparable safety profiles. Grepafloxacin's once-daily dosing regimen may offer advantages in terms of patient compliance.

Administration, Oral↗
PubMed1998

Randomized trial of trovafloxacin and ofloxacin for single-dose therapy of gonorrhea. Trovafloxacin Gonorrhea Study Group.

PURPOSE: To compare trovafloxacin, a new quinolone antibiotic with enhanced activity against Neisseria gonorrhoeae, with ofloxacin as single-dose oral therapy for uncomplicated gonococcal urethritis or cervicitis. PATIENTS AND METHODS: In this multicenter, double-blind trial, 625 patients (270 men, 355 women) with uncomplicated gonococcal urethritis or cervicitis received one 100-mg tablet of trovafloxacin or two 200-mg capsules of ofloxacin as a single dose under direct supervision. RESULTS: Single-dose oral therapy with trovafloxacin was equivalent both bacteriologically and clinically to ofloxacin. Among evaluable patients, N gonorrhoeae was eradicated in 99% of trovafloxacin recipients and in 98% of ofloxacin recipients. Each treatment was well tolerated; vaginitis was the most frequently observed side effect (4% trovafloxacin, 7% ofloxacin). CONCLUSION: Based on the results presented here, trovafloxacin is a promising agent for single-dose therapy of uncomplicated gonorrhea.

Adolescent↗
PubMed1998

Lateralization in chicks and hens: new evidence for control of response by the right eye system.

Domestic chicks show marked lateralization of visually evoked behaviour: left eye use is associated with, and has advantage for, the detection of novelty; right eye use is associated with the use of selected cues to determine what response should be given. Experiments undertaken to see how far such lateralization might be a transient feature of development showed similar patterns in both adults and chicks: (i) use of the right, but not the left, frontal field allowed the inhibition of pecks at a familiar social partner; (ii) in distant viewing, there was spontaneous preference for more use of the left eye when the social partner was familiar rather than unfamiliar. The chick data, in particular, support the hypothesis that the visual system fed by the right eye is especially competent in the control of response. This is shown by the ability of birds that are using the right eye to inhibit approach to an entirely novel potential social partner, and inhibit pecks at a familiar partner. The resemblances between chick and hen are sufficient to show that the basic adult pattern is already present in the young chick: the various developmental changes in features of lateralization, such as days of bias to control by one or other hemisphere, thus do not cause the appearance of the adult pattern.

Animals↗
PubMed1998

A molecular investigation of the obese phenotype in the Aston University strain of ob/ob mice and the Japanese Kuo Kondo mice.

The aim of this work was to determine the role of the ob gene in the obese phenotype observed in the Aston University Strain of ob/ob mouse and the Japanese Kuo Kondo (KK) mouse. After RT-PCR amplification of the ob RNA, the transcript was cloned into the vector pCR3 and three individual clones from each strain were sequenced. It was confirmed that the Aston University strain of ob/ob mice shared the same C-T mutation found in the Jackson Laboratory C57BL/6J ob/ob strain whereas the Japanese KK mice showed wild-type ob gene expression. This study indicates that the ob mutation has survived unchanged following the separation of the two strains of ob/ob mice, and secondly, that the molecular basis of the obese phenotype in the KK mice is not due to mutations in the ob gene.

Animals↗
PubMed1998

Pantoprazole-based 10-day triple therapy is effective in Helicobacter pylori eradication.

AIM: To investigate the efficacy of a short course of pantoprazole-based triple therapy in Helicobacter pylori eradication in a single-centre pilot study. METHODS: Patients with active or healed duodenal ulcer or with gastric erosions or gastritis, all of whom were H. pylori-positive, received 10 days of twice-daily open treatment with pantoprazole 40 mg, plus clarithromycin 250 mg and tinidazole 500 mg. H. pylori was assessed at entry and 28-35 days after the end of treatment by rapid urease test (at entry only), culture and antimicrobial sensitivity, histology and 13C urea breath test. The criterion for eradication was a negative result in all three tests. RESULTS: Seventy patients were treated, of whom four were excluded from analysis due to major deviations from the study protocol. Eradication of H. pylori was achieved in 57/66 patients (per protocol analysis 86% (95% CI: 78-95%)) and was higher in patients with organisms sensitive to nitroimidazole before treatment (sensitive: 47/53 (89%), insensitive: 10/13 (77%)). There was marked reduction in acute gastritis throughout the stomach while chronic gastritis decreased only in the corpus. Healing was achieved in all 24 patients with active duodenal ulcer. Treatment was complied with; only one patient missed one of the 20 doses. Adverse events were of mild or moderate intensity and did not require withdrawal from treatment. CONCLUSION: A short course of pantoprazole-based triple therapy is well tolerated and effective in eradicating H. pylori.

2-Pyridinylmethylsulfinylbenzimidazoles↗