Particle uptake and translocation across epithelial membranes

Oral delivery of drugs and vaccines has many advantages over other routes of administration. For example, for vaccination, enteric delivery may result in the induction of a mucosal immune response against pathogens which colonise and invade the mucosa. However, the oral delivery of peptide or protein drugs or antigens is beset with problems, such as gastrointestinal breakdown of labile molecules, low level of macromolecular absorption and, for vaccines, the poor immune response usually elicited by orally administered soluble antigens. Investigations are therefore in progress to develop means of increasing intestinal absorption and decreasing digestion of orally administered molecules. Molecules can be incorporated into biodegradable microparticles to reduce the effect of gut secretions and to enable the absorption of bioactive agents in an unaltered form. The uptake of microparticulates through the gut wall is accepted as a true biological phenomenon but the mechanism and route of uptake have not been established. Furthermore, in general, only small numbers of microparticles are translocated across epithelial membranes, possibly making these systems inappropriate for drug or vaccine delivery. This paper reviews particle uptake across the gastrointestinal tract and describes studies carried out to determine whether a humoral response can be elicited following oral administration of an antigen associated with biodegradable poly(DL lactide-coglycolide) microparticles. The use of lipid delivery vehicles to enhance microparticle uptake and the selective transport of microspheres across M cells is also described.

Culture of human vascular endothelial cells on an RGD-containing synthetic peptide attached to a starch-coated polystyrene surface: comparison with fibronectin-coated tissue grade polystyrene

A synthetic peptide, Gly-Arg-Gly-Asp-Ser-Pro-Lys (GRGDSPK), which includes the cell-adhesive region of fibronectin, Arg-Gly-Asp (RGD), was covalently bound to a dialdehyde starch (DAS) coating on a polymer surface by reductive amination. The GRGDSPK/DAS-coated surface was characterized by atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). AFM and SEM revealed a uniform, roughened, textured surface, much more so than standard polymer or adhesive protein-coated polymer surfaces. XPS showed that GRGDSPK binding to DAS occurred in dose-dependent fashion in the 0-200 micrograms ml-1 GRGDSPK concentration range, with a plateau happening in the 200-400 micrograms ml-1 range. AFM revealed a uniform peptide layer on the DAS surface with a maximum separation distance of 50 nm between peptides. Angle-dependent XPS showed that the peptide is present in nearly constant amounts to at least 10 nm depth of the DAS coating. The attachment, spreading and growth properties of anchorage-dependent human umbilical vein endothelial cells (EC) on the GRGDSPK/DAS-coated polystyrene surface were compared with a standard fibronectin-coated polystyrene surface. EC adhesion, spreading and growth properties were similar for cells plated on polystyrene surfaces coated with fibronectin (5 micrograms cm-2) and GRGDSPK (25-50 micrograms ml-1)/DAS. In contrast, EC adhesion, spreading and growth performance significantly increased for cells plated on GRGDSPK (100-200 micrograms ml-1)/DAS compared with the fibronectin-coated surface. These findings support the conclusion that the GRGDSPK/DAS-coated surface can be substituted for an adhesive protein-coated surface in the culture of anchorage-dependent cells.

A pilot survey of sexual function and quality of life following 3D conformal radiotherapy for clinically localized prostate cancer

PURPOSE

To assess the impact of high dose three-dimensional conformal radiotherapy (3D CRT) for prostate cancer on the sexual function-related quality of life of patients and their partners.

METHODS AND MATERIALS

Sixty of 124 consecutive patients (median age 72.3 years) treated with 3D CRT for localized prostate cancer were surveyed and reported being potent prior to treatment. The answers to survey questions assessing the impact of quality of life related to sexual function from these 60 patients and their partners forms the basis for this retrospective analysis.

RESULTS

Following 3D CRT, 37 of 60 patients (62%) retained sexual function sufficient for intercourse. Intercourse at least once per month was reduced from 71 to 40%, whereas intercourse less than once per year increased from 12 to 35%. Following treatment, 25% of patients reported that the change in sexual dysfunction negatively affected their relationship or resulted in poor self-esteem. This outcome was associated with impotence following treatment (p < 0.01). Patients who had partners and satisfactory sexual function appeared to be at a higher risk of having a negatively affected relationship or losing self-esteem if they become impotent (p < 0.05). Partners of patients who reported a negatively affected relationship or loss of self-esteem appear to be less likely to return the survey instrument used (p = 0.02).

CONCLUSIONS

More work is needed to evaluate the impact of radiotherapy and other treatments on the quality of life of patients and their partners to allow adequate informed consent to be given.

Prostate volumes defined by magnetic resonance imaging and computerized tomographic scans for three-dimensional conformal radiotherapy

PURPOSE

To compare the prostate volumes defined on magnetic resonance imaging (MRI), and noncontrast computerized tomographic (CT) scans used for three-dimensional (3D) treatment planning.

METHODS AND MATERIALS

Ten patients were simulated for treatment using immobilization and a retrograde urethrogram. 3D images were used to compare prostate volumes defined by MRI (4-6 mm thick slices) and CT images (5 mm thick slices). Prostate volumes were calculated in cm(3) using the Scanditronix 3D planning system. MRI/CT images were merged using bony anatomy to define the regions of discrepancy in prostate volumes.

RESULTS

The mean prostate volume was 32% larger (range-5-63%) when defined by noncontrast CT compared to MRI. The areas of nonagreement tended to occur in four distinct regions of discrepancy: (a) the posterior portion of the prostate, (b) the posterior-inferior-apical portion of the prostate, (c) the apex due to disagreement between a urethrogram based definition and the location defined by MRI, (d) regions corresponding to the neurovascular bundle.

CONCLUSION

There is a tendency to overestimate the prostate volume by noncontrast CT compared to MRI. Awareness of this tendency should allow us to be to more accurately define the prostate during 3-D treatment planning.

The role of estradiol, progesterone, and transforming growth factor on human endometrioma cell culture

The present study demonstrates several aspects of endometrioma cells in culture, namely, 1) cell growth, proliferation, and morphology, 2) effect of cell culture on estrogen and progesterone receptor concentration, 3) effect of estradiol, progesterone, and transforming growth factor. The tissue sample was obtained from ovarian endometriomas that were removed via laparotomy or laparoscopy. The tissue sample was digested with collagenase. After washing, the tissue was cultured in endothelial cell culture medium. Cell count was done by flow cytometry. Receptor study was done by immunohistochemistry. The results demonstrated the growth and proliferation of endometrioma cell in culture medium. Electron microscopy showed stroma-like cells. The cells lost their estrogen and progesterone receptors. Estradiol and progesterone added to these cultures did not affect the rate of growth and proliferation of the cells. Transforming growth factor significantly increased the rate of growth and proliferation of these cells.

Flutamide-induced liver toxicity including fatal hepatic necrosis

PURPOSE

To describe hepatic injuries in three patients who received flutamide prior to and during radiation treatment to make radiation oncologists aware of the need for careful monitoring of liver function during use of this drug.

METHODS AND MATERIALS

The records of three patients who developed abnormal liver function tests while undergoing total androgen suppression (TAS), as well as the literature concerning flutamide toxicity were reviewed and summarized.

RESULTS

Three of 34 patients treated with a TAS regimen incorporating flutamide developed significant hepatic abnormalities: elevated transaminases [2] and fatal hepatic necrosis [1]. Following the discontinuation of flutamide, two patients recovered fully. Unfortunately, the third patient's hepatic function continued to deteriorate, which culminated in his death. Transient elevations in serum transaminases, which do not exceed four times the upper limits of normal, are common and apparently without clinical significance. Unfortunately, idiosyncratic serious and/or fatal liver damage can occur. Significant liver toxicity may be obviated by monitoring of liver function tests (LFT) early in the course of flutamide therapy.

CONCLUSION

The incidence of hepatic toxicity associated with flutamide may be higher than previously suggested. To prevent the development of serious hepatic dysfunction, all patients receiving flutamide should be monitored clinically for signs and symptoms referable to hepatic injury and with serial LFT. We recommend baseline LFT followed by serial LFT at weeks 2, 4, 6, and 8 from the start of treatment with flutamide. Flutamide should be stopped promptly if significant liver abnormalities are detected.

Liposomal cyclosporine. Characterization of drug incorporation and interbilayer exchange

A number of previous studies have examined the application of liposomes as carriers for the immunosuppressive agent cyclosporine. These studies, however, have generated equivocal results, particularly with regard to the therapeutic properties of such systems. In the present work, we have characterized cyclosporine incorporation into well defined liposomes, large unilamellar vesicles, and have examined the stability of drug association. Contrary to some earlier reports, we show that only modest levels of cyclosporine can be accommodated in the liposomal membrane and that the extent of drug incorporation is greatly reduced as the bilayer cholesterol content is increased. Furthermore, we demonstrate that cyclosporine, despite its hydrophobic character, can rapidly exchange between vesicles. This raises the possibility that, after i.v. administration, drug migration to other blood components might negate the potential benefits arising from liposomal delivery. In a companion paper, therefore (Choice et al., Transplantation, 1995, this issue), we have followed the pharmacokinetics and biodistribution of liposomal cyclosporine in a study that examined the behavior of both the drug and the liposomal carrier.

Potency following high-dose three-dimensional conformal radiotherapy and the impact of prior major urologic surgical procedures in patients treated for prostate cancer

PURPOSE

To assess the impact of high-dose three-dimensional conformal radiotherapy (3DCRT) on potency in patients treated for clinically localized prostate cancer and to identify factors that might predict the outcome of sexual function following treatment.

METHODS AND MATERIALS

One hundred twenty-four consecutive patients treated with 3DCRT for localized prostate cancer at UCSF between 1991-1993 were included in this retrospective analysis. Patient responses were obtained from a mailed questionnaire, telephone interviews, or departmental records. Medial follow-up was 21 months.

RESULTS

Sixty patients reported having sexual function prior to 3DCRT, including 47 who were fully potent and 13 who were marginally potent. Of the remaining 64 patients, 45 were impotent, 7 were on hormones, 1 was status-postorchiectomy, and 11 were not evaluable. Following 3DCRT, 37 of 60 patients (62%) retained sexual function sufficient for intercourse. Of those with sexual function before irradiation, 33 of 47 (70%) of patients fully potent and 4 of 13 (31%) of patients marginally potent maintained function sufficient for intercourse (p < 0.01). Potency was retained in 6 of 15 (40%) patients with a history of a major urologic surgical procedure (MUSP) and in 31 of 45 (69%) with no history of a MUSP (p < 0.04). Transurethral resection of the prostate was the MUSP in eight of these patients, with four (50%) maintaining sexual function.

CONCLUSIONS

Patients who receive definitive 3DCRT for localized prostate cancer appear to maintain potency similar to patients treated with conventional radiotherapy. However, patients who are marginally potent at presentation or who have a history of a MUSP appear to be at increased risk of impotence following 3DCRT.

Savant characteristics in a child with developmental delay and deletion in the short arm of chromosome 20

The development outcome of a four-year-old boy with a deletion of the short arm of chromosome 20 is described. Despite a number of early medical problems, including infantile hypoglycemic convulsions secondary to growth hormone deficiency and delayed motor and language development, he has been reading (self-taught) since 2.5 years and currently has computer proficiency, and exceptional memory for maps and spatial locations, an extremely rich and active fantasy life, good diction, and an extensive spoken vocabulary. Neuropsychological evaluation revealed low-average intelligence with normal language, memory and attention functions, and impaired visuomotor and graphomotor ability and motor skills. He showed extremely advanced decoding and reading comprehension skills while mathematics, spelling and general knowledge abilities were average.

Combination chemotherapy for metastatic or recurrent carcinoma of the breast--a randomized phase III trial comparing CAF versus VATH versus VATH alternating with CMFVP: Cancer and Leukemia Group B Study 8281

PURPOSE

We sought to compare three doxorubicin-based therapies for metastatic breast cancer for response frequency, time to treatment failure (TTF), and survival.

MATERIALS AND METHODS

Women with metastatic breast cancer who had measurable disease, required laboratory tests, had received no prior chemotherapy for metastases, had a Cancer and Leukemia Group B (CALGB) performance status < or = 2, and provided informed consent were eligible. Treatment included the following: arm I--cyclophosphamide, doxorubicin, and fluorouracil (CAF); arm II--vinblastine, doxorubicin, thiotepa, and halotestin (VATH); and arm III--VATH alternating with cyclophosphamide, methotrexate, fluorouracil, vincristine, and prednisone (CMFVP) on cycles 3, 5, 7, 9, etc. Doses were modified for toxicities. Standard CALGB response and toxicity criteria were used.

RESULTS

Between August 1982 and February 1987, 497 women were entered and 491 were treated on study. Pretreatment characteristics were well balanced and the median follow-up duration was 79 months. There were no significant differences in response (complete [CR] plus partial [PR]) at 50% on arm I, 57% on arm II, and 51% on arm III. The median TTFs were 8, 8, and 9 months, respectively, in favor of arm III when compared with arm I (P = .028). The median survival times for treatment arms I, II, and III were 15, 17, and 17 months, respectively. After multivariate regression analyses, only estrogen receptors (ER), performance status, and number of metastatic sites influenced TTF and survival. Leukopenia was the most common grade 3 or 4 toxicity, occurring in 90%, 80%, and 92% of patients per arm, respectively. Lethal toxicities were seen in four, five, and six women, respectively. Overall, there were more grade > or = 3 toxicities on arm II than I, and most occurred on arm III (P = .02).

CONCLUSION

The VATH regimen appears similarly effective to the CAF regimen as initial therapy. Alternating CMFVP with VATH did not improve response rate or survival. After accounting for other variables, treatment arm was not related to outcome. New therapeutic regimens are still needed.

Affinity, conservation, and surface exposure of hemopexin-binding proteins in Haemophilus influenzae

Haemophilus influenzae can acquire heme from hemopexin for use as a source of both essential porphyrin and iron. In classical ligand-binding studies, we observed time-dependent, saturable, and displaceable binding of human 125I-labelled hemopexin to intact cells of H. influenzae type b (Hib) strain 760705 grown in an iron-restricted medium. From these experiments, which demonstrate that hemopexin associates with a single class of binding site, the affinities (Kds) and receptor numbers were calculated for heme-hemopexin (Kd, 205 nM; 3,200 receptors per cell) and apohemopexin (Kd, 392 nM; 4,400 receptors per cell). Thus, Hib expresses a specific hemopexin receptor which shows some preference for the heme-protein complex. Affinity chromatography on hemopexin-Sepharose 4B of detergent-solubilized membranes from Hib strain 760705 results in the copurification of three proteins with molecular masses of 57, 38, and 29 kDa. Trypsinization of whole cells of Hib 760705 abolishes hemopexin binding and correlates with the disappearance of the 57-kDa hemopexin-binding protein and appearance of a 52-kDa species which does not bind either hemopexin in ligand blot assays or a monoclonal antibody (MAbT11-30) raised against the 57-kDa protein. From immunoblotting assays and NH2-terminal amino acid sequence analysis, the 38-kDa protein isolated following hemopexin affinity chromatography was identified as the porin protein P2. These data, taken together with the receptor-binding studies which support a single class of hemopexin-binding site, suggest that P2 and the 29-kDa protein function as accessory proteins to the 57-kDa hemopexin-binding protein to facilitate the uptake of heme from receptor-bound hemopexin. To determine whether hemopexin binding and the 57-kDa protein are conserved in Haemophilus strains, whole-cell dot blots and immunoblots of the outer membrane proteins prepared from strains belonging to each of 21 different Hib outer membrane protein subtypes, six nontypeable strains, and five Haemophilus parainfluenzae strains were probed with either hemopexin or MAbT11-30. Only the H. parainfluenzae strains which lack the 57-kDa protein do not bind hemopexin. Since H. influenzae has also been shown to produce a soluble 100-kDa hemopexin-binding protein, cell-free culture supernatants were also examined for the presence of this protein. Apart from Hib 760705 and H. parainfluenzae, the 100-kDa hemopexin-binding protein was detected in all the other Haemophilus strains. The abilities of Hib 760705 to both bind and acquire heme from hemopexin without expressing a 100-kDa soluble hemopexin-binding protein show that in strain 760705, this 100-kDa protein is not essential for the utilization of heme from hemopexin.

Behavioural interventions for HIV/AIDS prevention

OBJECTIVES

The aim of this study was to identify and critically review behavioural interventions in the HIV prevention and sexual health fields.

METHODS

Electronic and hand searches were conducted to retrieve relevant published and unpublished reports of outcome evaluations. A methodological review was carried out to identify those with sufficient methodological strengths to generate reliable conclusions as to effectiveness. Soundly designed studies were defined as those which met the four core criteria of employing control groups, providing pre- and post-intervention data and reporting on all targeted outcomes.

RESULTS

A total of 68 separate reports of outcome evaluations were located. Only 18 were judged to be methodologically adequate. Major problems found were lack of a control group or non-equivalent/unbalanced control groups, small sample sizes, failures to report pre-intervention measures, short follow-up, and high attrition rates. Academic reviewers were more likely than the authors of papers to judge reports of evaluations as providing insufficient information to assess effectiveness.

CONCLUSION

Evaluation design in this field needs to be improved. Recommendations include more use of randomized controlled trials and the raising of publication standards by journals.

Effect of starch-containing glove powder on wound healing in the rat

The effect of the starch-containing powder BioSorb on wound healing was examined in an immunocompetent and a T cell-deficient animal model. Wounds were tested by tensionometry to give values of resilience, ultimate strength, toughness and extension. Starch significantly decreased the resilience (P < 0.03), ultimate strength (P < 0.004), and toughness (P < 0.006) of wounds in the immunocompetent model but was not shown to affect the healing of wounds in T cell-depleted animals. When the uncontaminated wounds of the two groups were compared, those from T cell-depleted animals were tougher (P < 0.04) and less extensile (P < 0.0002). These results suggest that starch impairs wound healing by its effect on the T cell-mediated immune system, and that this system may also be involved in regulation of the reparative process because its absence leads to tougher wounds.

Sexual health education interventions for young people: a methodological review

OBJECTIVES

To locate reports of sexual health education interventions for young people, assess the methodological quality of evaluations, identify the subgroup with a methodologically sound design, and assess the evidence with respect to the effectiveness of different approaches to promoting young people's sexual health.

DESIGN

Survey of reports in English by means of electronic databases and hand searches for relevant studies conducted in the developed world since 1982. Papers were reviewed for eight methodological qualities. The evidence on effectiveness generated by studies meeting four core criteria was assessed. Judgments on effectiveness by reviewers and authors were compared. PAPERS: 270 papers reporting sexual health interventions.

MAIN OUTCOME MEASURE

The methodological quality of evaluations.

RESULTS

73 reports of evaluations of sexual health interventions examining the effectiveness of these interventions in changing knowledge, attitudes, or behavioural outcomes were identified, of which 65 were separate outcome evaluations. Of these studies, 45 (69%) lacked random control groups, 44 (68%) failed to present preintervention and 38 (59%) postintervention data, and 26 (40%) omitted to discuss the relevance of loss of data caused by drop outs. Only 12 (18%) of the 65 outcome evaluations were judged to be methodologically sound. Academic reviewers were more likely than authors to judge studies as unclear because of design faults. Only two of the sound evaluations recorded interventions which were effective in showing an impact on young people's sexual behaviour.

CONCLUSIONS

The design of evaluations in sexual health intervention needs to be improved so that reliable evidence of the effectiveness of different approaches to promoting young people's sexual health may be generated.