Association of Prostate Specific Antigen Kinetics after Testosterone Recovery with Subsequent Recurrence: Secondary Analysis of a Phase III Randomized Controlled Trial

PURPOSE/OBJECTIVE(S)

The combination of short-term androgen deprivation therapy (ST-ADT) with prostate radiotherapy (RT) is a standard of care for patients with localized prostate cancer (LPCa). After cessation of ST-ADT, it takes about 8 to 10 months for the testosterone (T) to recover to supracastrate levels, which could drive changes in PSA kinetics. It largely remains unknown whether early changes in PSA kinetics after T recovery could predict for subsequent biochemical relapse.

MATERIALS/METHODS

We performed a secondary analysis of a phase III randomized controlled trial in which patients with newly diagnosed LPCa with Gleason score £7, clinical stage T1b to T3a, and PSA <30 ng/mL were randomly allocated to neoadjuvant and concurrent ADT for 6 months starting 4 months before prostate RT (76 Gy in 38 fractions over 7.5 weeks) or concurrent and adjuvant ADT for 6 months starting simultaneously with prostate RT. Clinical assessment and laboratory investigations were repeated 1 month after completion of ADT, every 4 months for the first 2 years, every 6 months for the next 3 years, and annually thereafter. We calculated the PSA doubling time (PSADT) based on PSA values up to 18 months after recovery of T to a supracastrate level (>50 ng/dL). Patients with ³3 PSA measurements after T recovery to supracastrate level were included in this analysis. Fine and Gray cumulative incidence of biochemical recurrence (BCR) was calculated in patients with PSADT at or above median versus below median. Deaths were considered as competing events. All endpoints were calculated from the time of T recovery to supracastrate level. Subdistribution hazard ratios (sHR) with 95% confidence intervals (CI) were estimated for association of PSADT with relative incidence of recurrence using competing risk regression after adjusting for tumor stage, pre-treatment PSA, Gleason score, treatment regimen, and age at randomization.

RESULTS

Overall, 311 patients were eligible for this analysis. Median PSADT was 8 months. Cumulative incidence of BCR at 10 years was 31.0% and 20.7% in patients with PSADT <8 months and ³8 months, respectively. Longer PSADT was associated with a significantly lower risk of cumulative incidence of BCR (sHR for PSADT as a continuous variable 0.43, 95% CI: 0.28-0.66; sHR for PSADT ³8 months 0.54, 95% CI: 0.30-0.99). After adjustment for time to recovery of T to supracastrate level in addition to the aforementioned variables, longer PSADT (³8 months) was associated with lower risk of cumulative incidence of BCR (sHR: 0.53, 95% CI: 0.27-1.01).

CONCLUSION

These findings suggest that early PSA kinetics within 18 months of recovery of T to a supracastrate level predict for subsequent biochemical failure. Taking account of early changes in PSA after testosterone recovery may allow for recognition of potential failures earlier in the disease course and thereby permit greater personalization of management decisions.

Impact of Concomitant Medications on Biochemical Outcome in Localised Prostate Cancer Treated with Radiotherapy and Androgen Deprivation Therapy

AIMS

Several classes of concomitant medications have been shown to affect oncological outcomes in patients with prostate cancer (PCa). We assessed the association between the use of commonly prescribed concomitant medications and biochemical relapse-free survival (bRFS) in patients with localised PCa treated with radiotherapy and androgen deprivation therapy (ADT).

MATERIALS AND METHODS

A secondary pooled analysis of two phase III randomised trials was carried out. In the first trial, patients with localised PCa with clinical stage T1b-T3, prostate-specific antigen <30 ng/ml and Gleason score ≤7 were treated with radical radiotherapy and 6 months of ADT starting 4 months before or concomitantly with radiotherapy. In the second trial, patients with high-risk PCa were treated with radical radiotherapy and 36 months of ADT with randomisation to three-dimensional conformal or intensity-modulated radiotherapy. Information on concomitant medications was collected from the medical record. Univariable and multivariable Cox regression was used to identify factors associated with bRFS.

RESULTS

Overall, 486 patients were evaluable. The median follow-up was 125 months; 10-year bRFS was 83.7%. On univariable analysis, receipt of metformin was significantly associated with worse bRFS. Ten-year bRFS was 73% and 85% for patients with and without concomitant metformin (adjusted hazard ratio 2.11, 95% confidence interval 1.03-4.33). Similar evidence of an association was observed with sulfonamide-based α1-receptor blockers (adjusted hazard ratio 2.72, 95% confidence interval 1.31-5.66). However, no such association was seen with receipt of quinazoline-based α1-receptor blockers (adjusted hazard ratio 1.09, 95% confidence interval 0.42-2.82). There was no significant association between bRFS and receipt of all other medication classes considered.

CONCLUSIONS

In this population of patients with localised PCa treated with radiotherapy and ADT, receipt of concomitant metformin and sulfonamide-based α1-receptor blockers was associated with inferior biochemical outcome. Randomised trials are required to assess the true effect of these medications on oncological outcomes in localised PCa.

Benthic ecological status of Algerian harbours

This work is an overview of all available benthic data collected in the Algerian harbours between 1983 and 2001. So, total of 571 stations were reported in the 10 major Algerian harbours along the Algerian coast (1200km). Two main categories of harbours were distinguished according to their hydrodynamic regime and volume of water exchange between inner harbour basins and the entrance of the harbours. Univariate, multivariate, benthic indices and Biological Traits of Life approaches were applied on stations sampled in the late 1990s and long-term observations in six out of these ten harbours. These approaches assessed the main characteristics and ecological statuses from these south Mediterranean harbours. One of the main characteristics of the Algerian harbours was the very high species diversity (847 species). Although all the fauna was dominated by pollution-tolerant species; some harbours such as Bethioua and Djendjen hosted normal benthic communities as found in the open sea, but also included some pollution indicator species typical of a slight polluted system. On the contrary, the newly constructed port of Skikda showed perturbed benthic communities in relation to hydrocarbon pollution. Biological Traits of Life analysis reinforced the separation of benthic species along a gradient reflecting their sensitivity or tolerance to pollution. This response was related to an increase in organic matter content, probably associated with a general organic and metal contamination, from the entrance of the harbour to the innermost basins in areas with weak circulation, high sedimentation rate and concentrations of pollutants. Except for Oran harbour, where the poor to moderate ecological status remained unchanged with time, the other harbours showed an improvement or a slight degradation. A strategy of long-term monitoring should be promoted, based on a restricted and selected number of stations characteristic of the different basins and water masses occupying the harbours.

Use of lean principals to improve flow of patients with fractured neck of femur--the HOPE study

We describe the implementation of a care pathway for patients with fractured neck of femur (NOF) using Lean and Six Sigma principles. After introduction of the Lean pathway, 32 patients out a total of 86 (37%) with fractured NOF were admitted to the Trauma Ward within 4 hours of presentation to the hospital; prior to implementation this was 16 patients out of a total of 59 (27%). Post-Lean an earlier mean theatre start time of 8.40am was achieved, resulting in a 38 minute increase in daily theatre time. An additional 52 patients (12%) received surgery within 24 hours of admission, resulting in 1 night length of stay reduction. Lean methodology proved an effective method to guide change resulting in an improved journey for the patient and significant workflow gains.

Medical device security

Medical device security represents a growing problem within the healthcare industry. An increasing number of medical devices and systems contain critical health related information for which integrity, availability, and confidentiality must be maintained. HIPAA's Security Rule requires that US healthcare providers have a security program addressing this problem in place by April 21, 2005. Through a collaborative effort, ACCE and ECRI have developed the first comprehensive guideline for implementing the security management and risk analysis process for medical technology.

Terminal protein-induced stretching of bacteriophage phi29 DNA

Stretching of DNA molecules helps to resolve detail during the fluorescence microscopy of both single DNA molecules and single DNA-protein complexes. To make stretching occur, intricate procedures of specimen preparation and manipulation have been developed in previous studies. By contrast, the present study demonstrates that conventional procedures of specimen preparation cause DNA stretching to occur, if the specimen is the double-stranded DNA genome of bacteriophage phi29. Necessary for this stretching is a protein covalently bound at both 5' termini of phi29 DNA molecules. Some DNA molecules are attached to a cover glass only at the two ends. Others are attached at one end only with the other end free in solution. The extent of stretching varies from approximately 50% overstretched to approximately 50% understretched. The understretched DNA molecules are internally mobile to a variable extent. In addition to stretching, some phi29 DNA molecules also undergo assembly to form both linear and branched concatemers observed by single-molecule fluorescence microscopy. The assembly also requires the terminal protein. The stretched DNA molecules are potentially useful for observing DNA biochemistry at the single molecule level.

First measurement of transferred polarization in the exclusive ep-->e'K+Lambda--> reaction

The first measurements of the transferred polarization for the exclusive e-->p-->e(')K+Lambda--> reaction have been performed at Jefferson Laboratory using the CLAS spectrometer. A 2.567 GeV beam was used to measure the hyperon polarization over Q2 from 0.3 to 1.5 (GeV/c)(2), W from 1.6 to 2.15 GeV, and over the full K+ center-of-mass angular range. Comparison with predictions of hadrodynamic models indicates strong sensitivity to the underlying resonance contributions. A nonrelativistic quark-model interpretation of our data suggests that the ssmacr; quark pair is produced with spins predominantly antialigned. Implications for the validity of the most widely used quark-pair creation operator are discussed.

The bacteriophage straight phi29 portal motor can package DNA against a large internal force

As part of the viral infection cycle, viruses must package their newly replicated genomes for delivery to other host cells. Bacteriophage straight phi29 packages its 6.6-microm long, double-stranded DNA into a 42 x 54 nm capsid by means of a portal complex that hydrolyses ATP. This process is remarkable because entropic, electrostatic and bending energies of the DNA must be overcome to package the DNA to near-crystalline density. Here we use optical tweezers to pull on single DNA molecules as they are packaged, thus demonstrating that the portal complex is a force-generating motor. This motor can work against loads of up to 57 pN on average, making it one of the strongest molecular motors reported to date. Movements of over 5 microm are observed, indicating high processivity. Pauses and slips also occur, particularly at higher forces. We establish the force-velocity relationship of the motor and find that the rate-limiting step of the motor's cycle is force dependent even at low loads. Notably, the packaging rate decreases as the prohead is filled, indicating that an internal force builds up to approximately 50 pN owing to DNA confinement. Our data suggest that this force may be available for initiating the ejection of the DNA from the capsid during infection.

Effect of gastrin and anti-gastrin antibodies on proliferation of hepatocyte cell lines

Gastrin (G-17) and its precursor glycine-extended gastrin (G-17-gly) have been shown to be trophic to some gastrointestinal tumors. This in vitro study assessed the effect of G-17, G-17-gly, anti-gastrin antibodies (anti-G-17), and the CCK-B receptor antagonist PD135,158 on three hepatoma cell lines (PLC/PRF/5, HepG2 and MCA-RH7777) and an embryonic liver cell line (WRL68). The pancreatic adenocarcinoma cell line AR42J was used as a positive control. G-17 and G-17-gly caused significant proliferation of AR42J and WRL68 cell lines. G-17-gly but not G-17 induced significant proliferation of the PLC/PRF/5 cell line. Anti-G-17 and PD135,158 significantly inhibited unstimulated AR42J and WRL68 cell lines. Anti-G-17 also inhibited the proliferative effects of G-17 and G-17-gly on AR42J, WRL68, and PLC/PRF/5 cell lines, whereas PD135,158 inhibited the proliferative effect of G-17 only. G-17 and G-17-gly as well as anti-G-17 and PD135,158 had no effect on HepG2 and MCA-RH77777 cell lines. It is concluded that G-17-stimulated proliferation is mediated via the CCK-B receptor and G-17-gly via a separate, as yet uncharacterized, receptor. There may therefore be a role for gastrin in embryonic hepatocellular proliferation and perhaps also in the proliferation of some hepatocellular tumors.

Antibodies raised against the extracellular tail of the CCKB/gastrin receptor inhibit gastrin-stimulated signalling

INTRODUCTION

Gastrin acts to stimulate gastric acid secretion and is an acknowledged growth factor for human gastrointestinal (GI) cancer. The identity of the exact receptor type mediating the growth promoting effects of gastrin in tumours is uncertain. However, the best-characterised gastrin receptor is the CCK receptor type B (CCKB)/gastrin receptor. The anti-GRE1 antibody is a polyclonal, affinity-purified antibody raised against GRE1, a synthetic 21 amino acid peptide homologous to part of the extracellular, N-terminal tail of the CCKB receptor. We have recently proven that GRE1 antiserum specifically localises CCKB receptors on CCKB receptor transfected NIH3T3 cells and human gastrointestinal tumour cells by Western blotting and immunocytochemistry. GRE1 antiserum also inhibits liver invasion in the C170HM2 colorectal liver-metastasis model.

AIM

To relate the ability of GRE1 antiserum to displace G17 from CCKB receptors with its impact on cellular transduction effects.

METHODS

Radioligand binding studies were performed with 125IG17 and Calcium mobilisation studies by use of the fluorescent dye Fura 2-am.

RESULTS

GRE1 antiserum competitively displaced 50% radiolabelled gastrin-17 from whole cell NIH3T3 CCKB transfectants at a protein concentration of 250 microg x ml(-1). GRE1 antiserum did not stimulate calcium ion influx in the transfectant NIH3T3 cells when used at a range of protein concentrations. Pre-incubation with GRE1 antiserum was required to inhibit gastrin-stimulated calcium ion influx. This was found to be concentration-dependent, with inhibition shown at 30 and 5 microg x ml(-1) but not at 500 ng x ml(-1) or below.

CONCLUSION

The GRE1 antiserum is specific for the CCKB receptor and may act to inhibit gastrin-stimulated signalling in tumour cells.

Structure of the bacteriophage phi29 DNA packaging motor

Motors generating mechanical force, powered by the hydrolysis of ATP, translocate double-stranded DNA into preformed capsids (proheads) of bacterial viruses and certain animal viruses. Here we describe the motor that packages the double-stranded DNA of the Bacillus subtilis bacteriophage phi29 into a precursor capsid. We determined the structure of the head-tail connector--the central component of the phi29 DNA packaging motor--to 3.2 A resolution by means of X-ray crystallography. We then fitted the connector into the electron densities of the prohead and of the partially packaged prohead as determined using cryo-electron microscopy and image reconstruction analysis. Our results suggest that the prohead plus dodecameric connector, prohead RNA, viral ATPase and DNA comprise a rotary motor with the head-prohead RNA-ATPase complex acting as a stator, the DNA acting as a spindle, and the connector as a ball-race. The helical nature of the DNA converts the rotary action of the connector into translation of the DNA.

Demonstration of new sites of expression of the CCK-B/gastrin receptor in pancreatic acinar AR42J cells using immunoelectron microscopy

The CCK-B/gastrin receptor has been characterised in both normal and tumour tissues. Endocytosis of the CCK-B/gastrin receptor has recently been demonstrated and this has similarly been described for other peptide receptors. In addition, ligand and ligand-receptor translocation to the nucleus has been demonstrated for other peptides. The aim of this study was to identify the sites of expression of the CCK-B/gastrin receptor in the known CCK-B/gastrin receptor bearing pancreatic acinar AR42J cells. The specificity of the CCK-B/gastrin receptor antibody (alpha-CCKBR-Ser antibody) was demonstrated by inhibition ELISA studies, radioligand inhibition studies and immunofluorescence binding studies on AR42J cells. Western blotting and immunogold electron microscopy techniques were used to identify the receptor in AR42J cell preparations. The affinity purified alpha-CCKBR-Ser antibody was shown to be specific for the CCK-B/gastrin receptor. The receptor was expressed on the cell membrane, in the cytoplasm and within the nucleus. Isoforms of the receptor protein identified in extra-nuclear and nuclear extracts ranged in molecular weight from 58 to 66 kDa. We conclude that the CCK-B/gastrin receptor is not only expressed on the cell membrane, but also in the cytoplasm and nucleus of AR42J pancreatic acinar cells.

A comparison of an anti-gastrin antibody and cytotoxic drugs in the therapy of human gastric ascites in SCID mice

The therapeutic effect of antibodies raised by the immunogen Gastrimmune was compared with both a CCKB/gastrin receptor antagonist, CI-988, and 5-Fluorouracil/leucovorin in a gastric cancer model. The human gastric ascites cell line, MGLVA1asc, produced and secreted progastrin and glycine-extended gastrin as determined by radioimmunoassay and immunocytochemistry. Cells were also stained with an antiserum directed against the human CCKB/gastrin receptor. MGLVAI asc cells were injected i.p. into SCID mice. Antibodies raised by Gastrimmune immunization of rabbits (affinity for G17 of 0.15 nM and GlyG17 of 0.47 nM) were passively infused i.p. and significantly enhanced survival by up to 5 days (p=0.0024 from vehicle controls). The enhancement in survival was not significantly different from that achieved by treatment with 5-Fluorouracil and leucovorin. A CCKB/gastrin receptor antagonist, CI-988, did not affect survival with cells injected at 7.5 x 10(5) cells/mouse but significantly increased the survival of mice injected with a lower cell innoculum of 5 x 10(5) cells/mouse from 30 to 35 days (p=0.0186). At this lower innoculum antibodies raised by Gastrimmune induced complete survival in 2 animals with the remaining dead by day 36 (p=0.0022). Thus, both endocrine and autocrine pathways mediated by precursor and mature gastrin molecules may be jointly operational in the gastric cancer scenario and may be important targets for therapeutic agents.

Expression and processing of gastrin in hepatocellular carcinoma, fibrolamellar carcinoma and cholangiocarcinoma

BACKGROUND/AIMS

Gastrin is a trophic factor within the normal gastrointestinal tract and is also a mitogen for a number of gastrointestinal and non-gastrointestinal tumours. Precursor forms of gastrin including progastrin (proG) and glycine-extended gastrin (G-gly) as well as the fully processed amidated gastrin (G-NH2) are expressed by tumours. There has been little study of the role of gastrin in either normal liver or liver tumours. The aim of this study was to identify the expression of CCK-B/gastrin receptor (CCK-BR), proG, G-gly and G-NH2 in normal liver and liver tumours.

METHODS

Tissue sections from patients with hepatocellular carcinoma, fibrolamellar carcinoma, cholangiocarcinoma as well as normal liver biopsies were assessed for expression of CCK-BR and gastrin isoforms.

RESULTS

Most liver tumours express CCK-BR and are able to process gastrin as far as proG and G-gly, although not as far as the amidated form. There appears to be little expression of the receptor and no expression of precursor forms of gastrin in normal liver.

CONCLUSIONS

Liver tumours express the CCK-BR and precursor forms of gastrin. This expression may be associated with tumour proliferation.

Expression of CCKB/gastrin receptor isoforms in gastro-intestinal tumour cells

Anti-serum raised against the human cholecystokinin B (CCKB)/gastrin receptor was used in Western blotting to differentiate the cellular locations of receptor isoforms expressed by human gastro-intestinal (GI) tumour cell lines. Using anti-serum directed against the amino-terminal extracellular tail of the CCKB/gastrin receptor, 8/9 cell lines were shown to express immunoreactive proteins of either m.w. 70 or 40 kDa, or both. Both isoforms were found to be associated with intracellular, non-nuclear membranes, whereas only the 70 kDa protein was expressed in the plasma membrane. Receptor expression was related to gastrin production and secretion. Both progastrin and glycine-extended gastrin-17 were produced and secreted by the tumour cell lines; however, carboxy amidated gastrin was not detected by radioimmunoassay. A CCKB/gastrin receptor transfectant NIH3T3 cell line did not produce detectable gastrin and showed exclusive expression of the 70 kDa receptor on the plasma membrane. One cell line had <50 pg/ml cell-associated progastrin and no detectable receptor form. Cell lines expressing 50-150 pg/ml had both 40 and 70 kDa receptor forms. Those expressing >150 pg/ml progastrin had only the 40 kDa isoform, which was shown to be exclusively expressed on intracellular, non-nuclear membranes, in one of the cell lines. Of the 4 cell lines exclusively expressing the lower m.w. receptor, 3 had gastrin present within the cell, which was not secreted. Thus, if cell-associated gastrin induces a proliferative effect, it may be by an intracrine pathway. Our study has identified the presence of CCKB/gastrin receptor isoforms in different cellular locations and may help toward understanding the complex autocrine and intracrine pathways mediated by gastrin peptides.

Encephalomalacia associated with vitamin E deficiency in commercially raised emus

Thirteen of 64 emus on a commercial emu farm in Ohio exhibited neurological signs that included backward staggering, incoordination, generalized weakness, and sitting on their hocks with head retracted backward. Eight of the birds showing such signs were found dead. Two of these emus were necropsied, and no significant gross lesions were observed. Major histopathological lesions were found in the cerebellum and included multiple malacic foci in association with neuropil rarefaction and astrogliosis within the white matter of folia. In addition, the hepatic vitamin E level of one emu was determined at the Michigan State University Animal Health Diagnostic Laboratory (MSU-AHDL) to be 14.61 micrograms/g dry weight. This vitamin E level was in the lower percentile (35%) of 30 emu liver samples examined at MSU-AHDL. A diagnosis of vitamin E-associated encephalomalacia was made based on clinical signs, gross and histological lesions, and liver vitamin E levels.

Pre-clinical evaluation of the Gastrimmune immunogen alone and in combination with 5-fluorouracil/leucovorin in a rat colorectal cancer model

Mature and post-translational precursor gastrin forms are growth factors for colorectal tumours. The immunogen Gastrimmune is composed of the amino terminus of gastrin-17 linked to diphtheria toxoid and raises antibodies in situ which neutralise amidated and glycine-extended gastrin-17. The aim of the study was to determine the effect of treatment with 5-fluorouracil(5-FU)/leucovorin on the antibody titres induced by Gastrimmune and the effect of combination therapy on the growth of the rat colon tumour DHDK12. Gastrimmune was administered to rats s.c. at 3 weekly intervals. The rat colon tumour line DHDK12 was injected into the abdominal wall of BDIX rats. Combinations of 5-FU/leucovorin were injected i.v. on days 1, 3 and 5, with the cycle repeated every 4 weeks. Antibody titres were measured by an ELISA technique. Antibody titres were followed for 40 weeks after Gastrimmune (500 microg.ml(-1)) immunization, with titres peaking between 10 and 20 weeks after a single immunisation and falling by week 30. At termination, no effect was observed on either the histological appearance of the gastro-intestinal tract or the proliferation of the colonic mucosa. Pre- and post-treatment with 5-FU/leucovorin (30 mg.kg(-1)) had no effect on the kinetics and level of antibody response to Gastrimmune. Gastrimmune (200 microg.ml(-1)) and 5-FU/leucovorin combinations (12.5 and 20 mg.kg(-1)) increased the therapeutic effects on the in vivo growth of DHDK12 tumors when compared to the agents given singly. Gastrimmune immunisation may be a therapeutic option for the treatment of colorectal cancer in combination with 5-FU/leucovorin.

Pre-clinical evaluation of the Gastrimmune immunogen alone and in combination with 5-fluorouracil/leucovorin in a rat colorectal cancer model

Mature and post-translational precursor gastrin forms are growth factors for colorectal tumours. The immunogen Gastrimmune is composed of the amino terminus of gastrin-17 linked to diphtheria toxoid and raises antibodies in situ which neutralise amidated and glycine-extended gastrin-17. The aim of the study was to determine the effect of treatment with 5-fluorouracil(5-FU)/leucovorin on the antibody titres induced by Gastrimmune and the effect of combination therapy on the growth of the rat colon tumour DHDK12. Gastrimmune was administered to rats s.c. at 3 weekly intervals. The rat colon tumour line DHDK12 was injected into the abdominal wall of BDIX rats. Combinations of 5-FU/leucovorin were injected i.v. on days 1, 3 and 5, with the cycle repeated every 4 weeks. Antibody titres were measured by an ELISA technique. Antibody titres were followed for 40 weeks after Gastrimmune (500 microg.ml(-1)) immunization, with titres peaking between 10 and 20 weeks after a single immunisation and falling by week 30. At termination, no effect was observed on either the histological appearance of the gastro-intestinal tract or the proliferation of the colonic mucosa. Pre- and post-treatment with 5-FU/leucovorin (30 mg.kg(-1)) had no effect on the kinetics and level of antibody response to Gastrimmune. Gastrimmune (200 microg.ml(-1)) and 5-FU/leucovorin combinations (12.5 and 20 mg.kg(-1)) increased the therapeutic effects on the in vivo growth of DHDK12 tumors when compared to the agents given singly. Gastrimmune immunisation may be a therapeutic option for the treatment of colorectal cancer in combination with 5-FU/leucovorin.

The bacteriophage phi29 packaging proteins supercoil the DNA ends

Bacteriophage phi29 DNA with covalently bound terminal protein (DNA-gp3) and its left and right-end restriction fragments (L and R-DNA-gp3) sedimented faster in sucrose density gradients than their proteinase K-treated counterparts, and the faster sedimentation was both gp3 and Mg2+-dependent. Addition of gp16, the phi29 DNA packaging ATPase, further increased the sedimentation rates of both intact DNA-gp3 and L and R-DNA-gp3 fragments. Thus, DNAs with gp3 were more compact than gp3-free DNA, and gp16 further condensed the DNA-gp3 forms. [35S]gp16 cosedimented with the fast-sedimenting DNA-gp3 fragments, and the putative L-DNA-gp3-gp16 complexes were packaged preferentially into proheads in the defined in vitro system. Lariats of DNA-gp3 and L and R-DNA-gp3 observed by electron microscopy rationalized the sedimentation results, and lariats with multiple loops or coils increased tenfold in a preparation of L-DNA-gp3-gp16 complexes. The rapid sedimentation and the structure of the DNA-gp3-gp16 complexes were consistent with supercoiling of lariat loops, and treatment with topoisomerase I shifted fast-sedimenting complexes toward the uncoiled lariat position in sucrose density gradients. DNA-gp3 has a maturation pathway in which the packaging proteins gp3 and gp16 supercoil the DNA ends, probably as a prerequisite for efficient interaction with the prohead.

Gastrimmune raises antibodies that neutralize amidated and glycine-extended gastrin-17 and inhibit the growth of colon cancer

The effect of gastrin neutralization was evaluated on the in vivo growth of the rat colon line, DHDK12, which expressed cholecystokinin B/gastrin receptors and secreted glycine-extended gastrin-17 (G17). Gastrin neutralization was achieved by administration of the immunogen, Gastrimmune, which is composed of the amino terminal portion of G17 linked to a diphtheria toxoid. A rat-specific version of Gastrimmune was used to preimmunize rats, with control animals receiving diphtheria toxoid only. The antibodies raised neutralized both carboxy-amidated and glycine-extended G17. The tumor was implanted into the muscle layer of the abdominal wall, and rats immunized with Gastrimmune had significantly reduced median cross-sectional tumor areas (70.2% reduction; P = 0.005) and weights (56.5% reduction; P = 0.0078)) when compared to control rats. Histological analysis revealed that the tumors had an enhanced degree of necrosis, with the area of viable tumor in the Gastrimmune-immunized rat reduced to 40.3% compared to 58.6% in the control rats (P = 0.003). Immunization with Gastrimmune raised antibodies that inhibited the growth of a rat colon tumor. This could have been mediated by neutralization of both serum G17 and cell-associated precursor gastrin molecules.

Anti-gastrin antibodies raised by gastrimmune inhibit growth of the human colorectal tumour AP5

The neutralising ability of rabbit anti-gastrin-17 (G17) antiserum raised by Gastrimmune, an immunogen constructed of the N-terminal portion of human G17 conjugated to diptheria toxoid (DT), was evaluated. The anti-serum (denoted anti-G17: DT) was shown to displace 125[I] G17 from the gastrin receptors on AR42J cells. The therapeutic effect of the rabbit anti-G17:DT anti-serum was evaluated on a freshly derived human colorectal cancer cell line, AP5, which was shown to express both gastrin receptors and gastrin immunoreactivity as assessed by immunocytochemistry. Rabbit anti-G17:DT anti-serum was shown to block basal in vitro growth of AP5 cells when used at an antigen binding capacity of 3.75 x 10(-9) M. The same dilution of anti-serum completely reversed growth stimulated by human G17 at concentrations of 1 x 10(-10) and 1 x 10(-9) M but did not inhibit growth at 1 x 10(-8) M G17. When AP5 was grown as a xenograft in nude mice, the sensitivity to the proliferative effect of human G17 was maintained. In addition, the basal growth of AP5 xenografts was significantly reduced by i.v. infusion of rabbit anti-G17:DT anti-serum when compared to treatment with rabbit anti:DT control anti-serum. Thus anti-G17:DT antibodies raised by Gastrimmune may be of clinical value in gastrin-sensitive tumours.

Residential segregation in Australian cities: a literature review

"In this review of literature dealing with the postwar immigrant experience in urban Australia, some of the key interpretations of residential segregation are assessed. The article focuses on studies which have examined ethnic clusters formed by southern Europeans in Sydney and Melbourne and more recently by Indochinese refugees. Much of the analysis to date has been based on measuring static residential patterns rather than social interaction, and the need to question the significance of ethnic concentrations which sometimes characterize the early stages of immigrant adaptation is suggested."

Sumatriptan and cerebral perfusion in healthy volunteers

1. The effect of sumatriptan on regional cerebral perfusion was studied in healthy volunteers. 2. Intravenous sumatriptan (2 mg) had no detectable effect on regional cerebral perfusion as measured using a SPECT system with 99technetiumm labelled hexemethylpropyleneamineoxime. 3. Sumatriptan had no effect on pulse, blood pressure or ECG indices. 4. All six volunteers experienced minor adverse effects during the intravenous infusion.

RNA dependence of the bacteriophage phi 29 DNA packaging ATPase

The activity of the DNA packaging adenosine triphosphatase (ATPase) of the Bacillus subtilis bacteriophage phi 29 is dependent upon prohead RNA. The 174 nucleotide viral-encoded RNA is positioned on the head-tail connector at the portal vertex of the phi 29 precursor shell (prohead). Here, the RNA interacts with the ATP-binding gene 16 product (gp16) to constitute the DNA-packaging ATPase and initiate DNA packaging in vitro. Both the prohead connector (gene 10 product, gp10) and gp16 may utilize an RNA recognition motif characteristic of a number of RNA-associated proteins, and the binding of gp16 by proheads shields the prohead RNA from RNase A. The ATPase activity of gp16 is stimulated fourfold by RNA and tenfold by proheads with RNA. RNA is needed continuously for the gp16/RNA ATPase activity and is essential for the gp16/prohead ATPase activity. The prohead, with its connector, RNA and associated gp16 in an assembly-regulated configuration, hydrolyzes ATP and drives phi 29 DNA translocation.

Impact of crime on the rural elderly

Two hundred and seven persons over 65 years of age were interviewed to determine the impact of crime on their lives. The setting was during a much publicized series of assaults on the rural elderly in their homes. Seventy two per cent were upset, 40% of the total were moderately upset and 26% suffered a major upset. Females and those over 75 years old were most upset. Some aspect of change of lifestyle was found in the vast majority.

In vitro packaging of bacteriophage phi 29 DNA restriction fragments and the role of the terminal protein gp3

Restriction fragments of bacteriophage phi 29 DNA-gp3 (DNA-gene product 3 complex) were packaged in a completely defined in vitro system that included purified proheads, the DNA packaging protein gp16 and ATP. Both left and right end DNA-gp3 fragments were packaged in this system, in contrast to the oriented and selective packaging of left end DNA-gp3 fragments in extracts; left ends could be packaged quantitatively in the defined system, while the packaging efficiency of right ends was generally about threefold lower. In addition, certain internal (non-end) DNA fragments were packaged at efficiencies of about 10% to 15%. Digestion of the gp3 with trypsin or proteinase K reduced the packaging of whole-length DNA by a factor of 2 or 4, respectively, and removal of the gp3 from whole-length DNA or end fragments with piperidine reduced packaging to the level of internal fragments. Though the terminal protein gp3 was non-essential for DNA translocation in the defined system, it stimulated packaging of left and right end fragments, and stabilized packaging of the left end. The packaging of end and internal DNA fragments of the related phage M2Y into phi 29 proheads was similar to that of phi 29 DNA fragments, and certain fragments of lambda DNA were packaged at the efficiency of the internal phi 29 DNA fragments. Selective packaging of DNA-gp3 left ends was restored by the addition of bacterial cell extracts or glycerol to the defined system, and these packaging conditions discriminated between phi 29 and M2Y DNAs that have distinct terminal proteins.

Cleaving the prohead RNA of bacteriophage phi 29 alters the in vitro packaging of restriction fragments of DNA-gp3

In vitro packaging of restriction fragments of the bacteriophage phi 29 DNA-gp3 (DNA-gene product 3 complex) in the defined system was dependent on prohead RNA. Truncated prohead RNAs were obtained by in situ RNase A digestion, isolated and sequenced. Proheads having the intact 174 base RNA were compared to proheads having RNAs of 120, 95, 71, 69 or 54 bases for the capacity to package the DNA-gp3 left and right ends and internal (non-end) fragments generated by the restriction enzymes EcoRI, HpaI and BstNI. Proheads with the 174 or 120 base RNAs packaged both left and right ends; internal fragments were packaged more efficiently by proheads with the 120 base RNA. Proheads with the 95 base RNA packaged DNA-gp3 left ends and internal fragments efficiently, but lost the capacity to package right ends. Only internal fragments were packaged by proheads with the 71 base RNA, and proheads having 69 or 54 base RNAs were inactive. RNA-free proheads were effectively reconstituted with purified 174 and 120 base RNAs to produce particles similar in biological activity to the proheads from which the RNAs were isolated. The 95 base RNA was the smallest RNA of the group that could reconstitute the prohead and direct fragment packaging, although packaging was inefficient. Alteration of the specificity of DNA fragment packaging with truncated prohead RNAs has delineated RNA domains that function in DNA-gp3 recognition and prohead binding.

A rat histone H4 gene closely associated with the testis-specific H1t gene

A rat histone H4 gene closely associated with the testis-specific H1t gene was isolated by screening the Sargent-Bonner rat genomic library using cloned human histone genes as probes. Both the H4 gene and the H1t gene are located on a 7-kb EcoRI genomic DNA fragment. Although the deduced amino acid sequence of the rat H4 histone is identical to that of the sequence of human histone H4, the nucleotide sequence of the coding region differs significantly from the coding region of the human H4 gene. Moreover, the relative spacing between the 5'-consensus sequence elements is unique for an H4 gene. S1-nuclease protection analyses reveal that both the H4 and H1t mRNA species are present in a fraction of rat testis cells highly enriched in pachytene spermatocytes, while only the H4 mRNA species is present in a rat myeloma cell line (Y3-Ag1.2.3). During a 1-h hydroxyurea treatment of the Y3 cells, which produces a 99% inhibition of DNA synthesis, the level of this H4 mRNA drops by only 50%, indicating that the stability of this mRNA is only partially coupled with DNA synthesis.

Induction of latent immunological memory in genetically nonresponsive mice

C57BL/10 mice exhibit major histocompatibility complex linked nonresponsiveness to hen egg white lysozyme (HEL). When these animals are primed with HEL in Freund's complete adjuvant (FCA), their secondary splenic plaque forming cell responses to aqueous HEL challenge are minimal to nonexistent. This notwithstanding, we show here that concomitant priming with both HEL and keyhole limpet hemocyanin (KLH) leads to an enhanced response to the HEL component following secondary challenge with an HEL-KLH conjugate. This enhancing effect can be transferred by nylon wool nonadherent spleen cells from HEL/FCA primed animals. Adoptive transfer studies with fractionated spleen cell populations suggest also that B cells are primed in these animals. Thus, animals which are incapable of mounting a secondary response to this antigen nevertheless appear to be primed at both the T-cell and B-cell levels following exposure to the antigen in FCA. The implications of this finding are discussed.

Cellular basis of genetic nonresponsiveness to egg white lysozyme

Utilizing radiation chimeras, we have investigated the cellular level at which the low immunological responsiveness to egg white lysozyme C57Bl/10 mice is expressed. Both NR----F1 (responder) and F1----NR combinations were assessed. The results demonstrate that C57Bl/10 bone marrow can give rise to hen egg white lysozyme responsive cells, but this response requires that the antigen be presented by cells derived from high responder animals.

A defined system for in vitro packaging of DNA-gp3 of the Bacillus subtilis bacteriophage phi 29

The bacteriophage phi 29 DNA-gene product 3 complex (DNA-gp3) has been efficiently packaged into proheads in a completely defined in vitro system. The phi 29 DNA packaging protein gp16, the product of gene 16, was overproduced in Escherichia coli and purified to near homogeneity. The purified gp16 packaged 23% of the DNA-gp3 added to purified proheads in the defined mixture, while gp16 in an extract of phage-infected cells packaged 26% of the DNA-gp3. No host proteins were required in the defined system. ATP-dependent packaging of DNA-gp3 in the defined system was optimal with approximately equal to 100 copies of gp16 per DNA-gp3, an amount similar to the production of gp16 per DNA-gp3 in phi 29-infected cells.