Five year follow up of a phase II study of cytotoxic immunotherapy combined with radiation in newly diagnosed prostate cancer

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Background: In the U.S. there are about 70,000 annual prostate cancer recurrences. The purpose of this study is to evaluate a product to decrease incidence of recurrence. This study is based on objective clinical responses in Phase I studies with AdV-tk (ProstAtak™, Advantagene, Inc) as monotherapy in recurrent disease and preclinical data demonstrating synergy between AdV-tk and radiation. AdV-tk is an adenoviral vector expressing the herpes thymidine kinase gene delivered to the prostate via TRUS-guided injection followed by 14 days of oral prodrug. The mechanisms of function involve direct tumor cytotoxicity, local elicitation of danger signals, recruitment and activation of antigen presenting cells and stimulation of systemic anti-tumor T-cell immunity. Method: AdV-tk was evaluated in combination with radiation in 66 newly diagnosed patients: 33 low risk (Arm A, PSA <10, Gleason <7, and T1c-T2a) and 33 intermediate-high risk (Arm B, PSA ≥10, Gleason ≥7, or T2b-T3). Arm A received two treatments with AdV-tk, immediately before and 14 days into radiation. Arm B received an additional treatment at initiation of androgen deprivation therapy. Results: Two surrogate and one definitive end-point were evaluated. Frequency of patients in Arm A with PSA nadir ≤0.2 ng/ml was 71% vs 56% in a control group of concurrent patients without AdV-tk. The two-year pathologic complete response (pCR) rate by sextant biopsy was 90% in Arm A and 94% in Arm B, compared to an expected range of 70–73%. Freedom from failure (FFF) after 60 month median follow up is 100% for Arm A and 90% for Arm B (95% for intermediate, 75% for high risk) vs best reported results of 79–90% for low risk and 48–79% for intermediate-high risk patients. The three failures in Arm B occurred within months after treatment leading to a Kaplan-Meier curve that plateaus at 90% beyond year 3. This is notably different than previous reports in which the curves continue to drop beyond year 5. Conclusion: These results suggest that AdV-tk combined with radiation therapy may significantly reduce the recurrence rate in patients with prostate cancer, particularly in patients with intermediate-high risk disease. A randomized controlled trial is warranted.

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Buccal cells as a source of DNA for comparative animal genomic analysis

The source of DNA of adequate quality and quantity is an important consideration in genome analysis. In many animal and livestock species, easy access to DNA will facilitate the rapid and reliable genotyping of a large number of individual individuals. Here, we describe the use, for the first time, of buccal cells from non-human mammalian species as a source of DNA template for PCR and restriction analysis. The buccal cells from the pig, cow and human, were used to amplify PCR fragments that were scanned SNPs and for comparative genome analysis. The work indicates that buccal cells are also adequate sources of DNA for genome analysis of animals that have been identified as priorities in comparative genomics.

Visual field constriction: accumulation of vigabatrin but not tiagabine in the retina

BACKGROUND

The antiepileptic drug (AED) vigabatrin (VGB) causes concentric visual field constriction. Anecdotal reports involving tiagabine (TGB) have implied that this may be a class effect of all AEDs with gamma-aminobutyric acid (GABA)-related actions. We investigated the pharmacokinetic and pharmacodynamic profiles of VGB and TGB in rat brain and eye.

METHODS

Adult male rats (n = 8) were administered 0.9% saline (control), VGB (500 or 1,000 mg/kg), or TGB (5, 10, or 20 mg/kg). At 1 (TGB) and 4 hours (VGB) postdosing, the animals were killed, a blood sample was obtained, their brains were dissected into five anatomic regions, and the retina and vitreous humor were isolated from each eye. Samples were analyzed for GABA concentrations and the activity of the enzyme GABA-transaminase (GABA-T). Plasma and tissue drug concentrations were also determined.

RESULTS

VGB treatment produced a decrease in the activity of GABA-T and a rise in GABA concentrations in all tissues investigated. This effect was most pronounced in the retina. VGB concentrations were as much as fivefold higher in the retina than in the brain. TGB was without effect on GABA concentrations and activity of GABA-T. TGB concentrations were notably lower in the retina than in the brain.

CONCLUSIONS

Accumulation of VGB in the retina, with or without an increase in GABA, may be responsible for the visual field constriction reported clinically. In contrast, TGB had no effect on GABA concentrations and did not accumulate in the retina. These results suggest that TGB is unlikely to cause visual field defects in humans.

Treatment of myelopathy in Sjögren syndrome with a combination of prednisone and cyclophosphamide

BACKGROUND

Peripheral neuropathy is a common complication of primary Sjögren syndrome, but central nervous system involvement also occurs and may be the only extraglandular manifestation. Sicca symptoms may also be minimal. Combinations of lesions along with relapses and remissions can suggest multiple sclerosis in the proper clinical setting, making the correct diagnosis elusive.

OBJECTIVES

To report a case of progressive transverse myelopathy with previous optic neuropathy in primary central nervous system Sjögren syndrome (CNS-SS), and to review 17 previously reported cases and the patient's responses to various therapies.

DESIGN

Case report and literature review.

SETTING

University hospital.

PATIENT

A 63-year-old Hispanic woman with a 10-month history of progressive spastic paraparesis associated with optic neuropathy and a T10 sensory level. Magnetic resonance imaging demonstrated multifocal, contrast-enhancing lesions in the spinal cord. The patient was diagnosed as having CNS-SS because of the presence of sicca symptoms, abnormal serological test results, and salivary gland biopsy results, which fulfilled San Diego criteria for "definite" Sjögren syndrome. She responded to treatment with a combination of prednisone and cyclophosphamide.

CONCLUSIONS

Diagnosis of primary CNS-SS requires a high index of suspicion and specialized clinical testing. Treatment with pulse doses of corticosteroids alone may be suboptimal, but results of treatment with a combination of corticosteroids and either cyclophosphamide or chlorambucil have been encouraging.

A neurochemical study of the novel antiepileptic drug retigabine in mouse brain

The novel antiepileptic drug, retigabine, has been reported to have multiple mechanisms of action, including potentiation of gamma -aminobutyric acid (GABA) and glutamate synthesis. We have investigated its effects on several GABA- and glutamate-related neurochemical parameters in mouse brain. Mice were administered retigabine either as a single dose or daily for 5 days. At 4 h after dosing, brains were removed and analysed for GABA, glutamate, and glutamine concentrations and for the activities of GABA-transaminase and glutamic acid decarboxylase. Single doses of retigabine significantly lowered brain concentrations of glutamate and glutamine. Repeated treatment significantly reduced the activity of GABA-transaminase. The drug was essentially without effect on all other parameters investigated. These results suggest that retigabine blocks GABA metabolism rather than enhancing GABA synthesis. In addition, the drug may also lower brain concentrations of the excitatory neurotransmitter glutamate and its precursor, glutamine. These effects may contribute to the antiepileptic action of retigabine.

Glutamic acid decarboxylase autoantibodies in controlled and uncontrolled epilepsy: a pilot study

There have been anecdotal reports of raised glutamic acid decarboxylase (GAD) autoantibodies in patients with refractory epilepsy. We measured serum GAD autoantibodies in 105 patients with idiopathic or symptomatic epilepsy. There was no significant difference in the absolute titre of GAD autoantibody between patients with controlled and uncontrolled epilepsy. However, four female patients with uncontrolled epilepsy had levels that were over three times above the highest detected in the seizure-free group, three of whom also tested positive for pancreatic islet cell antibodies. Larger scale studies, perhaps comparing different epilepsy syndromes, are required to determine the exact clinical role of GAD autoantibodies in epilepsy.

Gene expression during adventitious root formation in apple

A model system for adventitious root formation in woody plants was used to identify transcripts that are up-regulated during this process. 1 mm stem-disks from micropropagated shoots of the apple cultivar Jork 9 can be induced to form roots by treatment with the auxin indole butyric acid (IBA). Stem discs are placed on medium containing IBA for 24 hours and then transferred to IBA-free medium. Root initials become visible after 5-6 days and root elongation occurs within 7-9 days. The first visible cell divisions, which will give rise to the adventitious roots, are detectable 48 hours following IBA treatment. We have used this system to identify transcripts that are induced during adventitious root formation. Two techniques were employed in this analysis: differential messenger RNA display (DDRT) and mRNA representational difference analysis (RDA), a technique that couples PCR and subtractive hybridisation. Using both of these techniques a number of clones have been isolated that exhibit differential expression during auxin induced root formation. Both up-regulated and down-regulated transcripts have been identified. Expression of these genes has initially been verified by reverse northern blot analysis. Northern blot analysis with individual clones has confirmed the expression pattern observed in the reverse northern analysis. Tentative identities of some of the clones have been established by sequencing the partial cDNAs. Among the up-regulated transcripts are clones that share sequence homology with polygalacturonase and MAP kinases. A full-length cDNA for the most abundant up-regulated mRNA, a 2-oxoacid dependent dioxygenase, was characterised. This mRNA is expressed between 24 and 72 hours following IBA treatment of apple stem disks.

Vigabatrin and tiagabine are pharmacologically different drugs. A pre-clinical study

In light of theirclosely related mechanisms of action, and preliminary clinical evidence suggesting that they possess similar efficacies, it has been anecdotally suggested that vigabatrin and tiagabine may prove to be therapeutically indistinguishable. As a result, we have conducted a preclinical comparison of their anticonvulsant profile and mechanism of action. Pentylenetetrazol and maximal electroshock seizures were employed to determine the experimental anticonvulsant profile. Mechanisms of action were investigated using assays of gamma -aminobutyric acid (GABA), GABA-transaminase and glutamic acid decarboxylase in mouse brain and GABA uptake and GABA-transaminase in rat astrocyte cultures. Vigabatrin was without effect on either pentylenetetrazol- or maximal electroshock-induced seizures, whereas tiagabine increased the latency to pentylenetetrazol seizures and reduced the incidence of maximal electroshock seizures. In mouse brain assays, tiagabine was without effect, while vigabatrin increased GABA concentrations and reduced GABA-transaminase and glutamic acid decarboxylase activities. In cortical astrocyte cultures, vigabatrin reduced the activities of both GABA uptake and GABA-transaminase, whereas tiagabine blocked GABA uptake alone. These results suggest that vigabatrin and tiagabine have differing efficacy in experimental seizure models and distinct neurochemical effects. It is possible, then, that these drugs will have different spectra of activity and toxicity profiles in human epilepsy.

Effects of valproate, vigabatrin and tiagabine on GABA uptake into human astrocytes cultured from foetal and adult brain tissue

The antiepileptic agents sodium valproate (VPA), vigabatrin (VGB) and tiagabine (TGB) have been proposed to exert their effects, at least in part, by an action on the transport of the inhibitory neurotransmitter gamma-aminobutyric acid (GABA). This information has, however, been gleaned from studies employing experimental systems derived from animal tissues. We have conducted preliminary studies of the effects of VPA, VGB and TGB on the transport of GABA into primary cultures of human astrocytes, derived from both adult and foetal tissues. Astrocytes were prepared from cerebral cortical tissue obtained from patients undergoing surgery for intractable epilepsy, and from spontaneously aborted foetuses (16-24 weeks gestation). The cells were isolated via a series of enzymatic digestions, grown under standard culture conditions for around 21 days and then assayed for GABA uptake activity. VPA (1,000 microM), VGB (100 microM) and TGB (200 nM) all significantly (p < 0.05) reduced the uptake of GABA into primary cultures of human adult astrocytes following a one hour exposure. VPA (1,000 microM) and VGB (100 microM) similarly reduced GABA uptake into astrocytes derived from human foetal tissue, while TGB (200 and 500 nM) was without effect. The results of these preliminary studies suggest that VPA and VGB reduce GABA transport into both adult- and foetally-derived human astrocytes, whereas TGB appears active only in cells cultured from adult brain. Delayed development of the GAT-1 transporter in foetal tissue could explain this observation.

Thermoregulation during swimming and diving in bottlenose dolphins, Tursiops truncatus

Heat transfer from the periphery is in important thermoregulatory response in exercising mammals. However, when marine mammals submerge, peripheral vasoconstriction associated with the dive response may preclude heat dissipation at depth. To determine the effects of exercise and diving on thermoregulation in cetaceans, we measured heat flow and skin temperatures of bottlenose dolphins (Tursiops truncatus) trained to follow a boat and to dive to 15 m. The results demonstrated that skin temperatures usually remained within 1 degree C of the water after all exercise levels. Heat flow from peripheral sites (dorsal fin and flukes) increased over resting values immediately after exercise at the water surface and remained elevated for up to 20 min. However, post-exercise values for heat flow from the flukes and dorsal fin decreased by 30-67% when dolphins stationed at 15 m below the surface. The pattern in heat flow was reversed during ascent. For example, mean heat flow from the flukes measured at 5 m depth, 40.10 +/- 2.47 W.m-2, increased by 103.2% upon ascent. There is some flexibility in the balance between thermal and diving responses of dolphins. During high heat loads, heat transfer may momentarily increase during submergence. However, the majority of excess heat in dolphins appears to be dissipated upon resurfacing, thereby preserving the oxygen-conserving benefits of the dive response.

Regulation of zinc homeostasis in yeast by binding of the ZAP1 transcriptional activator to zinc-responsive promoter elements

Zinc homeostasis in yeast is controlled primarily through the regulation of zinc uptake. Transcription of the ZRT1 and ZRT2 zinc transporters increases in zinc-limited cells, and this induction is dependent on the ZAP1 gene. We hypothesized previously that ZAP1 encodes a zinc-responsive transcriptional activator. Expression of ZAP1 itself increases in zinc-limited cells. This response is also dependent on ZAP1 function through a potential positive autoregulatory mechanism. In this report, we describe the characterization of zinc-responsive elements (ZREs) in the promoters of the ZRT1, ZRT2, and ZAP1 genes. A ZRE consensus sequence, 5'-ACCYYNAAGGT-3', was identified and found to be both necessary and sufficient for zinc-responsive transcriptional regulation. We also demonstrate that ZREs are DNA binding sites for ZAP1. First, a dominant ZAP1 mutation, ZAP1-1(up), which causes increased expression of ZAP1-regulated genes in zinc-replete cells, exerted its effects specifically through the ZREs. Second, electrophoretic mobility shift assays and in vitro DNase I footprint analyses indicated that ZAP1 binds to ZREs in a sequence-specific fashion. These studies demonstrate that ZAP1 plays a direct role in controlling zinc-responsive gene expression in yeast by binding to zinc-responsive elements in the promoters of genes that it regulates.

Clumsiness in autism and Asperger syndrome: a further report

Clumsiness has been proposed as a diagnostic feature of Asperger syndrome (AS), a type of pervasive developmental disorder recently introduced in the ICD-10 and DSM-IV. However, the extent to which this symptom is specific to AS is not clear. To investigate this issue, we compared a sample of AS children with age- and sex-matched groups of children with autistic disorder and pervasive developmental disorder not otherwise specified (PDDNOS). Twelve subjects with AS (ICD-10/DSM-IV; 11 males; average age 11.4 years; mean full-scale IQ 104.9) were compared with 12 subjects with autistic disorder (DSM-III-R; II males; average age 10.3 years; mean full-scale IQ 78.4) and 12 subjects with PDDNOS (DSM-III-R; 10 males; average age 10.1 years; mean full-scale IQ 78.2). The BruininksOseretsky test, a standardized test of motor coordination, was administered blind by the same investigator to all the three groups. While coordination deficits were found in all three groups, children with AS were found to be less impaired than those with autistic disorder and PDDNOS. However, no significant relationship was found between coordination scores and diagnosis after adjusting for the level of intelligence. These findings suggest that some patients with AS may be less clumsy than those with autistic disorder and that this difference may be the result of their higher level of intelligence. Studies based on larger samples using multiple measures of coordination are needed to further clarify the role of clumsiness in the classification of pervasive developmental disorders.

Neurochemical actions of the desglycinyl metabolite of remacemide hydrochloride (ARL 12495AA) in mouse brain

1. Remacemide hydrochloride, a recently developed antiepileptic drug, is believed to exert its effects, at least in part, via its desglycinyl metabolite, ARL 12495AA. 2. We have investigated the effects of ARL 12495AA on several neurochemical parameters in mouse brain. Adult male ICR mice were randomized into two groups and administered ARL 12495AA (0-75 mg kg-1) intraperitoneally, either as a single dose or once daily for 5 days. 3. Six hours after the final dose, animals were killed and their brains removed. Brain tissues were analysed for concentrations of gamma-aminobutyric acid (GABA), glutamine and glutamate and for the activities of GABA-transaminase (GABA-T) and glutamic acid decarboxylase (GAD). 4. Single dose ARL 12495AA was without effect on any of the parameters investigated. 5. Repeated ARL 12495AA treatment did not alter brain concentrations of GABA and glutamine, but at a high dose there was a trend toward reduced brain glutamate concentrations (P = 0.10). 6. Repeated administration of ARL 12495AA at a high dose significantly increased GABA-T activity (P < 0.05) and decreased that of GAD (P < 0.05). 7. These findings may have relevance to the clinical use of remacemide hydrochloride in human epilepsy.

Neurochemical actions of gabapentin in mouse brain

Gabapentin (GBP) is a recently licensed antiepileptic, drug whose mode of action remains to be fully elucidated. The following studies were designed to investigate the effects of GBP on several gamma-aminobutyric acid (GABA) related neurochemical parameters in mouse brain. GBP (0-75 mg/kg) was administered by intraperitoneal injection either as a single dose or twice daily for 8 days. Animals were sacrificed 4 h after the final administration and their brains removed and analysed for concentrations of GABA, glutamate and glutamine and the activities of GABA-transaminase (GABA-T) and glutamic acid decarboxylase (GAD). Single dose GBP increased brain GABA-T activity and glutamine concentration but was without effect on GAD activity or the concentrations of GABA and glutamate. Following repeated treatment with GBP, brain GABA-T activity was consistently decreased and there was also a decrease in brain glutamate concentration. Repeated drug treatment was without effect on the activity of GAD or on the concentrations of GABA and glutamine. These results suggest that GBP has effects on the GABAergic system which may contribute to its antiepileptic and/or neuroprotective actions.

Neurochemical actions of vigabatrin and tiagabine alone and in combination in mouse cortex

1. The effects of repeated administration of the anticonvulsant compounds, vigabatrin (VGB) and tiagabine (TGB), on gamma-aminobutyric acid (GABA) concentration and the activities of GABA-transaminase (GABA-T) and glutamic acid decarboxylase (GAD) were investigated in mouse cortex. 2. VGB alone increased GABA levels and decreased GABA-T and GAD activities. 3. TGB alone was essentially without effect. 4. Low doses of VGB and TGB in combination increased GABA levels when neither drug had such an effect alone. 5. Despite this observation, this study failed to establish any conclusive evidence for an interaction between VGB and TGB that might help to explain their reported clinical synergism.

Effects of tiagabine and vigabatrin on GABA uptake into primary cultures of rat cortical astrocytes

Tiagabine (TGB) and vigabatrin (VGB) are two novel anticonvulsant compounds reported to exert their pharmacological effects via an action on the gamma-aminobutyric acid (GABA) system. We have investigated the effects of acute exposure of these drugs on the uptake of GABA into rat cortical astrocytes in primary culture. Astrocytes were prepared from the cerebral cortices of one day-old rat pups by a mechanical dissociation technique and were assayed for GABA uptake activity after 21 days in culture. Tiagabine (100-300 nM) and VGB (100 microM) reduced GABA uptake when compared to control at four hours post-exposure. GABA uptake was also reduced following eight and 24 hour exposures to 200 nM TGB. A combination of TGB (200 nM) and VGB (100 microM) treatments reduced GABA uptake when compared to both control and VGB treated cultures. These results support the efficacy of TGB as a GABA uptake inhibitor and suggest that VGB may also exert an effect by this mechanism.