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J G Smith

Publications and source records attributed to J G Smith.

At least 55 records · Page 3Linked to original sources

Overview and initial results of the very long baseline interferometry space observatory programme

High angular resolution images of extragalactic radio sources are being made with the Highly Advanced Laboratory for Communications and Astronomy (HALCA) satellite and ground-based radio telescopes as part of the Very Long Baseline Interferometry (VLBI) Space Observatory Programme (VSOP). VSOP observations at 1.6 and 5 gigahertz of the milli-arc-second-scale structure of radio quasars enable the quasar core size and the corresponding brightness temperature to be determined, and they enable the motions of jet components that are close to the core to be studied. Here, VSOP images of the gamma-ray source 1156+295, the quasar 1548+056, the ultraluminous quasar 0014+813, and the superluminal quasar 0212+735 are presented and discussed.

Journal Article↗

Regulation of G proteins and adenylyl cyclase in brain regions of caffeine-tolerant and -dependent mice.

Regulation of post-receptor signaling provides a mechanism of adaptation to chronic psychotropic drug treatment. In this study, the regulation of guanine nucleotide binding proteins (G proteins) and G protein-stimulated adenylyl cyclase activity was examined in brain regions of caffeine-tolerant and -dependent mice. Chronic caffeine doses were administered via mini-osmotic pumps over 7 days at 0, 42, 85 and 125 mg kg-1 day-1. These chronic caffeine doses were linearly correlated with plasma caffeine concentrations. In behavioral studies, the stimulant effects of acute caffeine on motor activity were significantly diminished in a dose-dependent manner after chronic caffeine, suggesting the development of tolerance. Abrupt discontinuation of chronic caffeine treatment (at 85 and 125 mg kg-1 day-1) produced a dose-dependent and reversible reduction in motor activity 24 h later, suggestive of a caffeine withdrawal syndrome. Utilizing quantitative immunoblotting methods, we found that hippocampal Gialpha1,2 and Gialpha3 subunits were significantly reduced by 20.2% and 11.1%, respectively, in caffeine tolerant/dependent mice (caffeine 125 mg kg-1 day-1 vs. vehicle controls). Decreases in inhibitory G protein subunit concentrations in hippocampus were accompanied by a significant increase (by 21%) in hippocampal G protein function, as measured by guanine nucleotide-stimulated adenylyl cyclase activity, in caffeine-treated mice. This same caffeine treatment also produced significant decreases in cortical Gsalpha subunits of 14.0%. Since short-term caffeine treatment has been shown to reduce adenylyl cyclase activity, chronic caffeine treatment could produce adaptive increases in G protein-stimulated adenylyl cyclase to oppose this effect via G protein regulation.

Adenylyl Cyclases↗

Symptom duration and delay in referral for palliative radiotherapy in cancer patients: a pilot study.

OBJECTIVE: To estimate the frequency of delay in referral for palliative radiotherapy (PRT), and to identify factors associated with delay. DESIGN: Prospective survey over three months in 1997. SETTING: Radiotherapy department of a cancer centre in Melbourne, Victoria. PARTICIPANTS: 158 consecutive patients prescribed PRT in the lung, breast, urology and haematology units. MAIN OUTCOME MEASURES: Duration of symptoms; incidence of "unreasonable" delay in referral; and incidence of negative clinical outcome associated with referral delay. RESULTS: The median duration of symptoms before prescription of radiotherapy was four weeks. Thirty-eight patients (24%) were considered to have had an unreasonable delay in referral, with median symptom duration of 15 weeks, and median delay in referral of 12 weeks. Causes of delay were classified as "diagnostic uncertainty" (29%), "other treatment given" (18%), "patient related" (18%), "language difficulty" (3%), and "unexplained" (32%). Twenty-seven of these 38 patients (71%) had negative outcomes, including persistent pain, neurological deterioration and persistent respiratory symptoms. CONCLUSIONS: These data suggest that delay in referral for PRT is not uncommon, has a variety of causes and can result in negative clinical outcomes. There appears to be a need for greater awareness of patients' symptoms and of the role of PRT among clinicians caring for patients with cancer.

Aged↗

Results of treating primary tumors of the trachea with radiotherapy.

PURPOSE: To report the efficacy of treatment and to identify prognostic factors that were predictive of survival in primary tumors of the trachea treated with radiotherapy. METHODS AND MATERIALS: The medical records of patients treated at the Peter MacCallum Cancer Institute in the period 1962 to 1995 were reviewed. Forty-two patients were eligible for the study and were treated with radiotherapy. Squamous cell carcinoma (SCC) was the commonest subtype and patients generally presented with long-standing respiratory symptoms. Eleven patients were planned for treatment with at least 50 Gy to the primary, while the rest were treated with lower doses. RESULTS: The estimated median survival for all patients was 5.7 months, with 13% surviving at 2 years. Univariate analysis revealed performance status, weight loss, and lymph node or distant metastatic involvement as significant prognostic factors. Patients planned for treatment with at least 50 Gy survived longer than patients treated with less than 50 Gy, but this was probably due to selection of patients with better prognostic factors for higher dose treatment.

Adenocarcinoma↗

Adenovirus-mediated transduction of intestinal cells in vivo.

The intestinal tract has many features that make it an attractive target for therapeutic gene transfer. In this study, replication-defective adenoviral vectors were used to explore parameters that may be important in administering gene therapy vectors to the intestine. After surgically accessing the intestine, an E1-, E3-deleted adenoviral vector encoding beta-galactosidase (beta-Gal) was directly injected into various regions of the small and large intestine of rats and rabbits. Significant transduction of the tissue was observed and histochemical staining was used to identify enterocytes as the primary targets of gene transfer. Expression of beta-Gal did not differ substantially when the virus was administered to the duodenum, ileum, or colon. When the vector was directly administered to segments of the distal ileum containing a Peyer's patch, transgene expression was approximately 10-fold higher than in segments lacking a Peyer's patch. In the Peyer's patches, a high level of expression was localized to epithelial cells, potentially M cells, overlying the lymphoid follicle domes. Transduction of these cells could have application in DNA-mediated oral vaccination. Administration of an adenoviral vector encoding a secreted alkaline phosphatase to the lumen resulted in expression and secretion of this gene product into the circulation. This finding demonstrates the potential of enterocytes to serve as heterotopic sites for the synthesis of heterologous gene products that would be secreted into the lumen of the intestinal tract or into the bloodstream.

Adenoviridae↗

Primary central nervous system lymphoma: age and performance status are more important than treatment modality.

PURPOSE: To assess prognostic factors and treatment modalities of patients with primary central nervous system lymphoma (PCNSL) in terms of response rates, patterns of failure and overall survival. METHODS AND MATERIALS: Sixty-two patients presenting with PCNSL between 1982 and 1994 at Peter MacCallum Cancer Institute with no evidence of human immunodeficiency virus infection were included in the study. Their median age was 60 years; World Health Organisation (WHO) performance status was > or = 2 in 85%. All patients were planned to receive whole brain irradiation; 7 also received spinal irradiation. The median planned dose to the target volume was 50.4 Gy. Twenty patients were planned to receive chemotherapy as well. Patients were followed up to June 20, 1995, giving a median follow-up for 14 surviving patients of 5.4 years, range 0.3 to 10.2 years. RESULTS: The clinical response rate to treatment was 77% [95% confidence interval (CI) 65 to 87%]. The estimated median overall survival was 20.6 months (CI 12.4 to 33.4 months). On univariate analysis male gender, age <60 years, WHO performance status < or = 1, treatment to the target volume > or = 45 Gy, and treatment with additional chemotherapy, were associated with a significantly better overall survival (p < 0.05). On multivariate analysis only age and performance status remained significant prognostic variables. Relapse involved the central nervous system or cerebrospinal fluid (CSF) in all patients with known sites of relapse except three who had ocular relapse only. There was a low incidence of relapse in the initial brain site (23% of known cases) and a high incidence (50%) of CSF/spinal cord relapse. Of 48 deaths, 15 were related to initial or subsequent treatment. CONCLUSIONS: Patient outcome is strongly influenced by age and performance status. Studies suggesting better survival for patients treated with chemoradiation may reflect patient selection rather than treatment variables. Optimal management remains to be defined. The high CSF/spinal relapse rate deserves particular attention.

Adolescent↗

Adenoviral transduction of melanoma cells with B7-1: antitumor immunity and immunosuppressive factors.

Previous studies in experimental models have demonstrated that the transduction of human or murine melanoma cells with the co-stimulatory B7-1 molecule induces effective antitumor immune responses. In order to develop B7-1 gene transfer as a therapeutic tool in the clinical management of melanoma, efficient means of in vivo gene transfer must be used. To this end we evaluated in vitro and in vivo immune responses associated with adenoviral transduction of murine and human melanoma cells with B7-1. Adenovirus-mediated transduction of human and murine melanoma cells with B7-1 leads to high-level transgene expression in vitro and in vivo and does not affect MHC class I and II expression. Adenovirus-delivered B7-1 induced antitumor immune responses, on the basis of observations that human melanoma cells transduced to express human B7-1 were able to co-stimulate allogeneic and autologous T cells to proliferate and that murine melanoma K1735 cells transduced to express murine B7-1 were rejected by syngeneic, immunocompetent mice. By contrast, intratumoral injection of an adenovirus encoding murine B7-1 failed to eliminate established murine melanoma (K1735) despite high-level transgene expression in tumor cells. Potent T cell inhibitory factor(s) secreted by both K1735 cells and select human melanoma cells may contribute to the failure to achieve protection in this setting. Thus, immune inhibitory melanoma-derived factors need to be taken into account when considering the clinical use of B7-1 immunotherapy.

Adenoviridae↗

Biodistribution of radiolabeled lipid-DNA complexes and DNA in mice.

The tissue biodistribution and expression of [33P]DNA-1-[2-[9-(Z)-octadecenoyloxy]ethyl]]-2-[8](Z)-heptadece nyl]-3 -[hydroxyethyl]imidazolinium chloride (DOTIM):cholesterol complexes and 33P-radiolabeled DNA expressing chloramphenicol acetyl transferase (CAT; 4.7 kB) were studied after intravenous (iv) injection in ICR mice. Mice were injected with 200 microL of complex containing DNA at 3 mg/kg or DNA alone. One group received 8 microCi of radioactivity and were sacrificed at 5 and 20 min, and 1, 2, 4 and 24 h post-dose (n = 4/time point). A second group received the equivalent of 3.9 microCi of radioactivity and were sacrificed at 20 min, and 2 and 24 h for subsequent whole body autoradiographic analysis (WBA; n = 2/time point). The tissue distribution of intact DNA was assessed by Southern blot at 24 h post-dose, whereas the integrity of complexes and DNA incubated in heparinized whole blood was studied separately. In further studies, the time course of expression in lung tissue over a 48-h period was examined, and the relative lung-expression of purified open circular (OC) versus supercoiled (SC) DNA at 24 h was evaluated. Approximately 42% of the radioactivity was found in the lungs 5 min after injection and about half this percentage was found in the liver. By 2 h, only 5% remained in the lungs, but 48% was present in the liver. No other tissue accumulated >5% of the dose throughout the duration of the study. WBA radiograms confirmed the tissue distribution results and highlighted significant accumulation of radioactivity in bone over time. Southern Blot analysis demonstrated intact DNA in many tissues 24 h after dosing. In contrast, the majority of DNA incubated in blood was degraded within 2 h, although the complexes afforded some protection relative to DNA alone. The OC DNA expressed equivalently to SC DNA in lung tissue (OC = 1035 +/- 183 pg; SC = 856 +/- 257 pg/mg soluble protein, n = 6, mean +/- SEM) at 24 h, and detectable levels of CAT were present within 2 h of dosing (21.3 +/- 7.2 pg, n >/= 8, mean +/- SD). The results confirm that DNA-DOTIM:cholesterol complexes are initially deposited in the lungs after iv administration.

Animals↗

Characterization and in vivo testing of a heterogeneous cationic lipid-DNA formulation.

PURPOSE: To identify characteristics of lipid-DNA complexes that correlate with in vivo expression data. METHODS: DOTIM:cholesterol liposomes (1:1 mole ratio) and DNA expressing chloramphenicol acetyl transferase (CAT) were complexed at a 4.2:1 mass ratio (cationic lipid:DNA). Complexes were fractionated by density gradient centrifugation. analyzed for particle size and zeta potential and quantitated using HPLC methods. The unfractionated complexes, "purified" fractions of the complexes, and purified complexes supplemented with liposomes were administered to mice by intravenous injection (i.v.) and intratracheal instillation (i.t.) and their ability to express gene product was assessed. RESULTS: Centrifugation separated two distinct populations within complexes one consisting of free liposomes and the other of lipid complexed with DNA. The vesicle diameter and zeta potential among separated fractions varied from 113 to 354 nm. and + 24 to + 34 mV respectively. Re-centrifugation of the 'purified' fractions containing the lipid-DNA population produced a single band. CAT expression in lung tissue 24 hr post-i.v. was observed with the unfractionated complex, but not the purified form. Some activity was 'restored' with the liposome-supplemented complexes. In contrast, the same series of complexes administered by i.t. resulted in no significant difference in lung expression (p=0.16 ANOVA). CONCLUSIONS: An uncomplexed liposome population exists within DOTIM:cholesterol-DNA complexes that influences the expression of complexes administered i.v. but not i.t..

Analysis of Variance↗

Butyric acid from the diet: actions at the level of gene expression.

A number of components present in the diet, although nutritionally nonessential, have been discovered to have beneficial effects toward both general health and disease prevention/protection. One such nutrient, butyric acid, can be derived in large quantities from bacterial fementation of dietary fiber in the bowel and is also a component of bovine milk. In gut fermentation, the production of butyric acid defines its delivery point; thus, the synthesis and site of action of butyric acid are in close proximity and have frustrated the investigation of its activities in vivo. Recent research has, however, revealed a number of activities of butyric acid toward isolated cells. In particular, its ability to modify nuclear architecture and induce death by apoptosis in colon cancer cells is arousing great interest. Butyric acid changes the structure of chromatin through its effects on posttranslational modifications, key modifications being acetylation and phosphorylation of the nuclear histones. Butyric acid can also modify the differentiation state of cells, and in the case of cancerous colonic cells overcomes their resistance to normal programmed death. Thus, the activities of this fermentation product of dietary fiber may contribute substantially to the decreased incidence of bowel cancer that has been associated with fiber intake.

Animals↗

Congenital anomalies of the hand.

This manuscript reviews the basic and most common types of congenital hand anomalies seen by the pediatrician. Each disorder is categorized into the standard classification system used, and the main highlights of each condition are detailed with representative illustrations. Other system anomalies associated with congenital hand problems are also identified.

Female↗

Radiotherapy treatment for isolated loco-regional recurrence of rectosigmoid cancer following definitive surgery: Peter MacCallum Cancer Institute experience, 1981-1990.

PURPOSE: To assess the success of external beam radiation treatment in the management of loco-regional recurrence of rectosigmoid cancer. METHODS AND MATERIALS: A retrospective analysis of 135 patients with locally recurrent rectosigmoid cancer presenting to Peter MacCallum Cancer Institute between January 1981 and December 1990 was undertaken. Patients were treated with three different dose ranges of radiotherapy: 50-60 Gy ("Radical" group), 45 Gy ("High-dose palliative" group), and <45 Gy ("Low-dose palliative" group). Symptomatic response rates and overall survival for each group were determined. RESULTS: Symptomatic response rates of 85, 81, and 56% were achieved in the radical, high-dose palliative, and low-dose palliative groups, respectively. Estimated median survival times were 17.9, 14.8, and 9.1 months for the radical, high-dose palliative, and low-dose palliative groups, respectively.

Adult↗

Intracranial administration of adenovirus expressing HSV-TK in combination with ganciclovir produces a dose-dependent, self-limiting inflammatory response.

Replication-defective adenovirus expressing the herpes simplex thymidine kinase gene (H5.010RSVtk) may be useful in treating human gliomas. To determine the toxicity of this therapeutic strategy, we injected H5.010RSVtk stereotactically into the normal brain of Wistar rats, cotton rats, and rhesus monkeys in conjunction with systemic ganciclovir (GCV) at 10 mg/kg per day. In the Wistar rat, 5.7 x 10(9) pfu resulted in histopathologic injury consisting of localized necrosis, mild gliosis, marked malacia, and focal astrocytosis; however, 1.0 x 10(8) pfu resulted in only mild gliosis and trace meningitis and approximates a "no toxic effect" dose. A dose of 1.0 x 10(9) pfu in both adenoviral immune and adenoviral naive cotton rats resulted in similar findings. In the rhesus monkey, doses ranging from 1.4 x 10(8) pfu to 1.5 x 10(11) pfu resulted in localized gliosis, necrosis, perivascular cuffing, meningitis, and roughly correlated in severity with increasing dose. No histologic evidence of toxicity was found in non-central nervous system (CNS) tissues, and no virus could be cultured from cerebrospinal fluid (CSF), blood, urine, and stool samples. All animals survived to prescribed end points without signs of general toxicity or neurologic symptoms, except for 2 of the rhesus monkeys, one of which became febrile and the other of which developed a grand mal seizure (both subsequently resolved). These toxicology studies define the parameters for developing a phase I clinical trial.

Adenoviridae↗

Australian multicentre phase II trial of paclitaxel in women with metastatic breast cancer and prior chemotherapy.

OBJECTIVE: To determine the efficacy and safety of paclitaxel given as a three-hour infusion in patients with metastatic breast cancer which had progressed despite hormonal therapy and/or chemotherapy. DESIGN AND SETTING: Multicentre phase it trial undertaken in five major centres or hospitals in Sydney, Melbourne and Adelaide. PATIENTS AND METHODS: 50 patients with clinically or radiologically measurable or evaluable metastatic breast cancer recruited between March and July 1993. All had received prior chemotherapy, with subsequent disease progression. INTERVENTION: Paclitaxel (Anzatax, Faulding) was given at a dose of 175 mg/m2 intravenously over three hours every three weeks for up to nine courses. MAIN OUTCOME MEASURES: Response rate (partial or complete); duration of progression-free survival; duration of survival; and adverse reactions. RESULTS: Patients had a median age of 51 years; 62% had received at least two prior drug regimens for metastatic breast cancer and 48% had anthracycline-resistant tumours. A median of six paclitaxel courses was given per patient. Overall response rate was 18% (95% confidence interval [95% CI], 9%-31%), with complete responses in four patients (8%). In patients with anthracycline-resistant tumours, response rate was 25% (95% CI, 10%-47%). Response was not influenced by extent of prior treatment. Estimated median progression-free survival was 4.1 months (95% CI, 3.2-6.0 months) and estimated median survival was 6.3 months (95% CI, 6.2-10.3 months). Treatment was well tolerated, with neutropenia the major toxic effect. CONCLUSIONS: Paclitaxel (three-hour infusion) has significant activity in heavily pretreated patients with metastatic breast cancer, including anthracycline-resistant tumours.

Adult↗

Topical diclofenac/hyaluronic acid gel in the treatment of solar keratoses.

A randomized double-blind controlled trial of 130 patients was performed to study the efficacy and tolerability of topical 3% diclofenac in 2.5% hyaluronic acid (HA) gel (active) versus gel containing 2.5% HA alone (control) in the treatment of solar keratoses. Patients were asked to apply trial gel to the target lesion twice a day and also sunscreen once a day for 24 weeks. The complete response rates were 29% for the active gel and 17% for the control gel. The difference was not statistically significant (P = 0.14). A high percentage of patients in both groups experienced a partial response to treatment (38% active, 45% control) but there was no significant difference in the spectrum of response between the two treatments (P = 0.18). Local adverse reactions occurred significantly more frequently in patients using the active gel (29% compared to 5% using control gel, P = 0.0002).

Administration, Topical↗

In vitro preclinical evaluation studies with the echinocandin antifungal MK-0991 (L-743,872).

The echinocandin MK-0991, formerly L-743,872, is a water-soluble lipopeptide that has been demonstrated in preclinical studies to have potent activity against Candida spp., Aspergillus fumigatus, and Pneumocystis carinii. An extensive in vitro biological evaluation of MK-0991 was performed to better define the potential activities of this novel compound. Susceptibility testing with MK-0991 against approximately 200 clinical isolates of Candida, Cryptococcus neoformans, and Aspergillus isolates was conducted to determine MICs and minimum fungicidal concentrations MF(s). The MFC at which 90% of isolates are inhibited for 40 C. albicans clinical isolates was 0.5 microg/ml. Susceptibility testing with panels of antifungal agent-resistant species of Candida and C. neoformans isolates indicated that the MK-0991 MFCs for these isolates are comparable to those obtained for susceptible isolates. Growth kinetic studies of MK-0991 against Candida albicans and Candida tropicalis isolates showed that the compound exhibited fungicidal activity (i.e., a 99% reduction in viability) within 3 to 7 h at concentrations ranging from 0.06 to 1 microg/ml (0.25 to 4 times the MIC). Drug combination studies with MK-0991 plus amphotericin B found that this combination was not antagonistic against C. albicans, C. neoformans, or A. fumigatus in vitro. Studies with 0 to 50% pooled human or mouse serum established that fungal susceptibility to MK-0991 was not significantly influenced by the presence of human or mouse serum. Results from resistance induction studies suggested that the susceptibility of C. albicans was not altered by repeated exposure (40 passages) to MK-0991. Erythrocyte hemolysis studies with MK-0991 with washed and unwashed human or mouse erythrocytes indicated minimal hemolytic potential with this compound. These favorable results of preclinical studies support further studies with MK-0991 with humans.

Amphotericin B↗