Feasibility and acute toxicities of radioimmunoguided prostate brachytherapy

PURPOSE

We present a technique that fuses pelvic CT scans and ProstaScint images to localize areas of disease within the prostate gland to customize prostate implants. Additionally, the acute toxicity results from the first 43 patients treated with this technique are reviewed.

METHODS AND MATERIALS

Between 2/97 and 8/98, 43 patients with clinical stage II prostate adenocarcinoma received ultrasound-guided transperineal implantation of I-125 or Pd-103 seeds. The median patient age was 70 years (range 49-79). Prior to treatment, the median Gleason score and prostate-specific antigen (PSA) were 6 (range 3-8) and 7.5 (range 1.8-16.6 ng/mL), respectively. The median follow-up was 10 months (range 2.9-20.4 months).

RESULTS

The median PSA value at 10 months is 0.7 ng/mL. Significant acute complications within the first month following implantation included 13 Grade I urinary symptoms, 24 Grade II urinary symptoms, 6 Grade III symptoms, and no Grade IV complications. Beyond 4 months, complications included 12 Grade I urinary symptoms, 17 Grade II urinary symptoms, 1 Grade III, and 1 Grade IV complications.

CONCLUSIONS

The image fusion of the pelvic CT scan and ProstaScint scans helped identify regions within the prostate at high risk of local failure, which were targeted with additional seeds during implantation.

Indinavir population pharmacokinetics in plasma and cerebrospinal fluid. The HIV Neurobehavioral Research Center Group

Plasma and cerebrospinal fluid (CSF) indinavir concentrations were measured by high-performance liquid chromatography. The median concentration in plasma exceeded that in CSF 10-fold. The modeled CSF curve was flat at 155 nM, and the estimated ratio of the areas under the CSF and plasma concentration-time curves was 6%. We conclude that CSF indinavir concentrations are lower than levels in plasma but exceed the clinical 95% inhibitory concentration range.

Macromolecular crowding perturbs protein refolding kinetics: implications for folding inside the cell

We have studied the effects of macromolecular crowding on protein folding kinetics by studying the oxidative refolding of hen lysozyme in the absence and presence of high concentrations of bovine serum albumin and Ficoll 70. The heterogeneity characteristic of the lysozyme refolding process is preserved under crowded conditions. This, together with the observation that the refolding intermediates that accumulate to significant levels are very similar in the absence and presence of Ficoll, suggests that crowding does not alter substantially the energetics of the protein folding reaction. However, the presence of high concentrations of macromolecules results in the acceleration of the fast track of the refolding process whereas the slow track is substantially retarded. The results can be explained by preferential excluded volume stabilization of compact states relative to more unfolded states, and suggest that, relative to dilute solutions, the rates of many protein folding processes are likely to be altered under conditions that more closely resemble the intracellular environment.

Immuno-capture differential display method (IDDM) for the detection of environmentally induced promoters in rhizobacteria

A rapid immunological method for trapping and selection of functionally regulated prokaryotic promoters is described. The method is based on application of a novel mini-Tn5 derived promoter probe (pUTTKZY-promoterless lacZY as a reporter and kanamycin resistance) to mutagenise a plant growth promoting fluorescent pseudomonad, Pseudomonas fluorescens 54/96. The transposon allows selection of operon fusion mutants (lacZY(+)) directly on media containing lactose as a sole carbon source as well as selection for kanamycin and lacZ (beta-galactosidase) expression on X-gal indicator media. We have extended the technique to target the surface expression of the induced lactose permease gene (lacY) from mutagenised libraries and the immuno-capture of bacteria with magnetic beads and anti-LacY monospecifc antisera. The benefits of the lacZY reporter are that a library can be rapidly generated and screened in vitro to isolate non-expressed mutants for further in situ screening. Here we demonstrate the development and utility of the technique and its potential as a differential display method for the isolation of promoters that direct regulated gene expression in the phytosphere, or under other imposed conditions.

Identification of conserved traits in fluorescent pseudomonads with antifungal activity

A collection of 29 fluorescent pseudomonads, some with known biological control activity against a range of phytopathogenic fungi, were characterized phenotypically and genotypically by comparing carbon source utilization patterns, suppression of Pythium ultimum both in planta and in vitro and the potential to produce known secondary metabolites. Fatty acid profiling and restriction fragment length polymorphism (RFLP) analysis of the ribosomal DNA operon (ribotyping) were used to determine the diversity of isolates. A small group of genetically related Pseudomonas spp. with similar properties was identified; each isolate produced a diffusible bioactive product in vitro and was active against Pythium ultimum in planta. However, other isolates that were able to suppress damping off disease but did not inhibit hyphal extension in vitro clustered outside this group. Phenotypic analyses revealed that the accumulation of C17:0 cyclopropane fatty acid (17CFA) and the production of hydrogen cyanide correlated significantly with biological control activity and with the antagonism of fungal development. The potential of 17CFA as a marker for the selection of fluorescent pseudomonads with biocontrol agent (BCA) potential was demonstrated by the isolation of a novel active strain. This was selected after the screening of 13 clonal groups of fluorescent pseudomonads identified from 500 isolates from the phytosphere of sugar beet. Levels of 17CFA synthesis possibly reflect the efficacy of the rpoS allele in particular strains.

Reconstitution of higher plant chloroplast chaperonin 60 tetradecamers active in protein folding

Unlike the GroEL homologs of eubacteria and mitochondria, oligomer preparations of the higher plant chloroplast chaperonin 60 (cpn60) consist of roughly equal amounts of two divergent subunits, alpha and beta. The functional significance of these isoforms, their structural organization into tetradecamers, and their interactions with the unique binary chloroplast chaperonin 10 (cpn10) have not been elucidated. Toward this goal, we have cloned the alpha and beta subunits of the ch-cpn60 of pea (Pisum sativum), expressed them individually in Escherichia coli, and subjected the purified monomers to in vitro reconstitution experiments. In the absence of other factors, neither subunit (alone or in combination) spontaneously assembles into a higher order structure. However, in the presence of MgATP, the beta subunits form tetradecamers in a cooperative reaction that is potentiated by cpn10. In contrast, alpha subunits only assemble in the presence of beta subunits. Although beta and alpha/beta 14-mers are indistinguishable by electron microscopy and can both assist protein folding, their specificities for cpn10 are entirely different. Similar to the authentic chloroplast protein, the reconstituted alpha/beta 14-mers are functionally compatible with bacterial, mitochondrial, and chloroplast cpn10. In contrast, the folding reaction mediated by the reconstituted beta 14-mers is only efficient with mitochondrial cpn10. The ability to reconstitute two types of functional oligomer in vitro provides a unique tool, which will allow us to investigate the mechanism of this unusual chaperonin system.

Cerebrospinal fluid HIV RNA originates from both local CNS and systemic sources

OBJECTIVE

To identify the sources of HIV virions in CSF by modeling treatment-associated HIV dynamics.

BACKGROUND

We postulated a model in which cell-free CSF virions originate from two major sources, namely, systemic non-CNS and CNS tissues, the latter including brain parenchyma and meninges. The model predicted that with initiation of antiretroviral therapy, the acute-phase decline in CSF HIV RNA levels would be controlled by the kinetics of the dominant virion source (systemic versus CNS). Based on prior observations, we hypothesized that the dominant source of CSF virions would shift from systemic to CNS in more advanced disease.

METHODS

Three patient groups were studied: Group 1 (n = 5): nondemented, with early HIV disease (CD4+ lymphocytes > or = 400/microL) or pleocytosis (CSF leukocytes > or = 4/microL); Group 2 (n = 5): nondemented, with advanced HIV disease (CD4+ < 400/microL) and no pleocytosis; Group 3 (n = 2): patients with HIV-associated dementia (HAD). All patients began a new, highly active antiretroviral treatment regimen and underwent serial lumbar punctures and phlebotomies.

RESULTS

For patients in Group 2, the rate of decline in CSF HIV RNA was slower than in plasma (p < 0.00001). For Group 1, the rate of decline in CSF was not different from plasma (p > 0.25). Patients with HAD showed high CSF HIV RNA after 5 to 6 weeks of treatment despite a 100-fold decrease in plasma HIV RNA.

CONCLUSIONS

CSF and plasma HIV dynamics became increasingly independent in advanced HIV disease, and the compartmental discrepancy was largest in HAD. Our findings suggest that viral replication in CNS tissues may constitute a major, independent source of CSF HIV RNA. In patients with HAD, brain parenchyma itself may be the principal CNS tissue source, and CNS-targeted treatment strategies may be required to eradicate this infection.

Ciprofloxacin-warfarin coagulopathy: a case series

Ciprofloxacin, when given to patients previously anticoagulated with warfarin, can occasionally cause an exaggerated hypoprothombinemic response and bleeding diatheses. Two such cases encountered at our institution are presented and data is combined with 64 cases reported to the Food and Drug Administration's (FDA) Spontaneous Reporting System (SRS) database, which included all cases reported from 1987 through 1997. Of 66 total cases the median age was 72 (range 36-94). The mean time to detection of the coagulopathy following the ciprofloxacin challenge was 5.5 days (n = 50). Hospitalization was reported in 15 cases, bleeding in 25 cases, and death in one case. The median prothrombin time (PT) and International Normalized Ratio (INR) was 38.0 (n = 13) and 10.0 (n = 23), respectively. The mean number of medications taken was 6.5 (n = 45). The mean time to correction was significantly shorter between the treated (2.5 days) and the untreated (4.0 days) groups (P < 0. 008). The ciprofloxacin-warfarin coagulopathy occurred most commonly in patients in their seventh decade and in those who require polypharmacy. Active treatment of the coagulopathy results in more rapid resolution than observation alone. Clinicians should be aware of the potential bleeding complications that can occur with the ciprofloxacin-warfarin drug-drug interaction.

Effects of macromolecular crowding on protein folding and aggregation

We have studied the effects of polysaccharide and protein crowding agents on the refolding of oxidized and reduced hen lysozyme in order to test the prediction that association constants of interacting macromolecules in living cells are greatly increased by macromolecular crowding relative to their values in dilute solutions. We demonstrate that whereas refolding of oxidized lysozyme is hardly affected by crowding, correct refolding of the reduced protein is essentially abolished due to aggregation at high concentrations of crowding agents. The results show that the protein folding catalyst protein disulfide isomerase is particularly effective in preventing lysozyme aggregation under crowded conditions, suggesting that crowding enhances its chaperone activity. Our findings suggest that the effects of macromolecular crowding could have major implications for our understanding of how protein folding occurs inside cells.

Laboratory heparin resistance in burn injury complicated by venous thrombosis

Anticoagulation with heparin is required in the management of the burn patient if their clinical course is complicated by venous thrombosis. Heparin therapy is commonly monitored by the activated partial thromboplastin time (APTT) but this assay can be unreliable in patients with acute inflammation because of an increase in plasma factor VIII levels that result in an underestimation of the heparin concentration. We report an example of heparin resistance that occurred in a patient who developed venous thrombosis following extensive second-degree burns. Heparin doses in excess of 60,000 units per day were required to produce a significant elevation in the APTT. The plasma factor VIII level was found to be markedly elevated to 455% and the plasma heparin concentration as determined by the anti-factor Xa assay was disproportionately elevated in relation to the APTT. Physicians treating patients with burn injury complicated by venous thrombosis should be aware of the potential development of factor VIII-related heparin resistance when large amounts of heparin are required to obtain a satisfactory elevation in the APTT. Measurement of the plasma heparin concentration will avoid excessive heparin administration and the serious bleeding which can result.

The impact of HIV-related neuropsychological dysfunction on driving behavior. The HNRC Group

HIV infection often results in neuropsychological (NP) impairment. In order to assess the impact that HIV-related NP deficits may have on automobile driving, we evaluated 68 HIV-seropositive drivers using an NP battery and two PC-based driving simulations. Thirty-two participants were classified as NP impaired; most (72%) evidenced only mild impairment, and none met criteria for HIV-associated dementia. After controlling for degree of immunosuppression and disease stage, NP-impaired participants failed a previously validated driving simulation at a much higher rate than cognitively intact participants [OR = 5.3, 95% CI (1.7, 17.0), p = .006]. Similarly, on a simulation of city driving, NP impaired participants were more likely to fail based upon the number of accidents [OR = 6.1, 95% CI (1.5, 24.6), p = .01]. Simulator performance was predicted by functioning in a number of NP domains, with NP tests accounting for 13-30% of the variance on the simulations. Although it would be premature to extrapolate these findings to impairment in on-the-road driving, they do argue for greater attention to the impact that even mild HIV-related NP deficits may have on driving skills.

Relevance of glutamate levels in the CSF of patients with HIV-1-associated dementia complex

Chronic hyperactivation of excitatory amino acid pathways in the CNS of patients infected with HIV-1 may contribute to the pathogenesis of HIV-1-associated dementia complex. However, no correlation between the concentration of glutamate in CSF (mean 3.3 micromol/L) and either HIV-1 infection or HIV-1-associated dementia complex was observed. The results clarify several important issues regarding analysis of glutamate in the CSF and the role of excitotoxins in HIV-1-associated dementia complex.

Ecological basis for biocontrol of damping-off disease by pseudomonas fluorescens 54/96

Pseudomonas fluorescens 54/96, originally isolated from the rhizosphere of sugar beet, has been shown to be commercially effective in field trials for the suppression of a number of fungal diseases of seedlings. In vitro and microcosm-based assays revealed that both the timing and method of application of bacteria were important for effective control of Pythium ultimum, the causative agent of damping-off disease. Following transposon mutagenesis (Tn5lac), mutants deficient for the suppression of Pythium ultimum infections of peas were isolated. Three major classes of insertional mutants of Ps. fluorescens 54/96 were identified which either inhibited sporulation, reduced mycelial growth or affected the regulation of bacterial metabolic activity. Evaluation of the metabolic capability of pathogen and antagonist revealed evidence for direct competition, as both the fungus and bacterium had similar sole carbon source nutrient utilization profiles. Further comparisons of the activity of the transposon mutants indicated that although the mechanisms of disease control were multifactorial, the most significant factor was the prevention of rapid spore germination in the presence of pea seeds.

Molecular chaperones: pathways and networks

Some proteins synthesized by growing eukaryotic cells are transferred along unidirectional pathways of molecular chaperones until the risk of aggregation has decreased and they can be released safely. Mature proteins denatured by stress may instead be handled by chaperones acting in branched, reversible networks.

Principles of protein folding in the cellular environment

The ability of newly synthesised protein chains to fold into their functional conformations has evolved within the complex intracellular environment. Until recently, however, this ability has been studied largely as the refolding of denatured mature proteins in dilute simple solutions. Recent work aimed at understanding how proteins fold in vivo has allowed some general statements to be postulated.

Optimal use of photomultipliers for chemiluminescence and bioluminescence applications

Photomultipliers are the preferred detectors for quantifying weak or short-lived light emissions. The quality of signal recovery has an upper limit imposed by the statistical nature of light detection. It is shown that the photon counting method can provide performance close to ideal, whereas performance in the current measuring method is degraded by noise in the multiplier gain process and by the nature of the dark current. Performance variations because of changes in temperature, shock, vibration and magnetic field effects are significantly reduced when using the photon counting method. The effects of dead-time can be corrected making photon counting superior to current measuring with regard to dynamic range. The benefits of using photon counting packages are presented.

A randomized trial of amitriptyline and mexiletine for painful neuropathy in HIV infection. AIDS Clinical Trial Group 242 Protocol Team

BACKGROUND

Painful sensory neuropathy is a common complication of HIV infection. Based on prior uncontrolled observations, we hypothesized that amitriptyline or mexiletine would improve the pain symptoms.

METHOD

A randomized, double-blind, 10-week trial of 145 patients assigned equally to amitriptyline, mexiletine, or matching placebo. The primary outcome measure was the change in pain intensity between baseline and the final visit.

RESULTS

The improvement in amitriptyline group (0.31+/-0.31 units [mean+/-SD]) and mexiletine group (0.23+/-0.41) was not significantly different from placebo (0.20+/-0.30). Both interventions were generally well tolerated.

CONCLUSIONS

Neither amitriptyline nor mexiletine provide significant pain relief in patients with HIV-associated painful sensory neuropathy.

Prostate cancer and prostate bed SPECT imaging with ProstaScint: semiquantitative correlation with prostatic biopsy results

BACKGROUND

ProstaScint (Cytogen Corporation, Princeton, NJ) murine monoclonal antibody imaging is FDA-approved for imaging of prostate cancer patients at high risk for metastatic disease and patients postprostatectomy with a rising serum prostate-specific antigen (PSA) level. ProstaScint is a murine monoclonal antibody which targets prostate-specific membrane antigen (PSMA). PSMA expression is upregulated in primary and metastatic prostate cancer. FDA Cytogen (Princeton, NJ) protocol studies using 111indium-labeled ProstaScint revealed correlation between areas of increased concentration in the prostate and biopsy-proven tumors in patients imaged pretherapy.

METHODS

In our study, four transverse, single-photon emission tomography (SPECT) images were isolated and regions of interest were selected and correlated with pretherapy prostate biopsy results. Prostate cancer and normal tissue prostate/muscle background (P/M) ratios were derived, so that postprostatectomy/radiation therapy patients could be evaluated for the presence of residual prostate cancer. Twenty-three pretherapy prostate cancer patients with quadrant/sextant biopsies had SPECT 96-hr 111indium ProstaScint pelvic images. The four transverse 1-cm slices above the midline penile blood pool were chosen, and four to six 27-30-pixel regions of interest were placed over the prostate bed. The background muscle region of interest was placed over the external obturator muscle region. The P/M ratio was calculated and compared to the quadrant/sextant prostatic biopsy result. The same procedure was applied to 17 posttherapy prostate cancer patients with rising PSA.

RESULTS

In the 23 pretherapy prostate cancer patients, there was a correlation between the P/M ratio of at least 3.0 in 32 of 35 prostatic cancer biopsy regions, and there was correlation with P/M ratios less than 3.0 in 82 of 89 negative biopsy regions. Seventeen posttherapy patients underwent ProstaScint studies. Six underwent biopsy, with typically one biopsy site per patient. All 6 had P/M ratios greater than 3.0 in the biopsied region. Five out of six biopsies revealed residual prostate cancer.

CONCLUSIONS

A prostate/muscle ratio was developed from 111indium ProstaScint regions of interest obtained on 1-cm SPECT transverse slices through the prostate bed in 23 patients preprostatic cancer therapy. A P/M ratio above 3.0 correlated in the majority of positive cases, and a P/M ratio below 3.0 was demonstrated in negative prostatic biopsy cases. The P/M ratio of above 3.0 or below 3.0 also separated those posttherapy prostate cancer patients with rising PSA who had residual prostate carcinoma in the prostate bed.

Cerebrospinal fluid tau protein is not elevated in HIV-associated neurologic disease in humans. HIV Neurobehavioral Research Center Group (HNRC)

We measured the concentrations of the neuron-specific protein, tau, in the cerebrospinal fluid (CSF) of 32 neurologically characterized HIV-infected (HIVpos) subjects and nine matched seronegative (HIVneg) controls using a sensitive ELISA assay. Of 32 HIVpos subjects, nine had HIV-associated neurocognitive disorders, and nine had clinically diagnosed peripheral neuropathies. CSF tau levels in subjects with HIV-associated neurocognitive disorders were similar to those in HIVneg subjects (185 +/- 83 vs. 223 +/- 106 pg/ml; P = 57). CSF tau levels in HIVpos subjects with peripheral neuropathies did not differ from those without neuropathies (320 +/- 190 vs. 251 +/- 185; P = 23). In summary, CSF tau levels were not elevated in patients with HIV-associated neurologic disease.