Spontaneous rupture of the right aortic sinus resulting in a sterile aorto-atrial fistula in a pet rabbit (Oryctolagus cuniculus)

Aortocardiac fistula is a broad term used to describe defects between the aorta and other cardiac chambers that can occur in humans and animals. A 1.5-year-old, 1.7 kg, male castrated Holland lop rabbit (Oryctolagus cuniculus) was presented for a two-week history of a heart murmur with corresponding cardiomegaly on radiographs. Physical examination confirmed a grade-V/VI continuous heart murmur on the right sternal border with a regular rhythm and a gallop sound. Echocardiography revealed an aortic-to-right-atrial fistula causing severe left-sided volume overload. Based on the echocardiographic findings, rupture of the right aortic sinus was suspected. Due to the poor prognosis, euthanasia was elected. On necropsy, a fistula was found connecting the right aortic sinus with the right atrium, without evidence of an inflammatory response nor evidence of an infectious etiology. The sudden onset of a heart murmur supported acquired fistulation from a ruptured aortic sinus (also known as the sinus of Valsalva), though a congenital malformation could not be completely excluded.

Autologous fat transplantation alters gene expression patterns related to inflammation and hypoxia in the irradiated human breast

BACKGROUND

Radiation-induced fibrosis, an adverse effect of breast cancer treatment, is associated with functional and cosmetic impairment as well as surgical complications. Clinical reports suggest improvement following autologous fat transplantation, but the mechanisms underlying this effect are unknown. A global gene expression analysis was undertaken to identify genetic pathways dysregulated by radiation and evaluate the impact of autologous fat transplantation on gene expression.

METHODS

Adipose tissue biopsies were taken synchronously from irradiated and contralateral non-irradiated breasts, before and 1 year after autologous fat transplantation. Whole-genome gene expression analyses were performed, and Hallmark gene set analysis used to explore the effect of radiotherapy and autologous fat transplantation on gene expression.

RESULTS

Forty microarrays were analysed, using bilateral biopsies taken from ten patients before and after autologous fat transplantation. Forty-five pathways were identified among the 3000 most dysregulated transcripts after radiotherapy in irradiated compared with non-irradiated breast (P ≤ 0·023; false discovery rate (FDR) no higher than 0·026). After autologous fat transplantation, 575 of the 3000 genes were again altered. Thirteen pathways (P ≤ 0·013; FDR 0·050 or less) were identified; the top two canonical pathways were interferon-γ response and hypoxia. Correlative immunohistochemistry showed increased macrophage recruitment in irradiated tissues.

CONCLUSION

The present findings contribute to understanding of how autologous fat transplantation can ameliorate radiation-induced fibrosis. This further supports the use of autologous fat transplantation in the treatment of radiation-induced fibrosis. Surgical relevance Clinical studies have indicated that autologous fat transplantation (AFT) stimulates regression of chronic inflammation and fibrosis caused by radiotherapy in skin and subcutaneous fat. However, there is a paucity of biological evidence and the underlying processes are poorly understood. Human data are scarce, whereas experimental studies have focused mainly either on the effect of irradiation or AFT alone. The present results indicate that radiotherapy causes dysregulated gene expression in fibrosis-related pathways in adipose tissues in humans. They also show that AFT can cause a reversal of this, with several dysregulated genes returning to nearly normal expression levels. The study provides biological evidence for the impact of AFT on radiation-induced dysregulated gene expression in humans. It supports the use of AFT in the treatment of radiation-induced fibrosis, associated with severe morbidity and surgical challenges.

A literature-based algorithm for the assessment, management, and monitoring of drug-induced QTc prolongation in the psychiatric population

BACKGROUND

Certain psychotropics and a number of other medications used to treat medical conditions in psychiatric patients can increase the risk of prolonging the corrected QT (QTc) interval on the electrocardiogram, which puts patients at risk of life-threatening ventricular arrhythmias such as torsades de pointes. Pharmacists are often consulted about medications which are known to prolong the QTc interval. Although this information is often accessible, advising how to identify, assess, manage, and refer psychiatric patients at risk for drug-induced QTc prolongation is more challenging.

OBJECTIVES

The objective of this project was first to review the literature, which describes guidelines and recommendations for the assessment and management of drug-induced QTc prolongation, and then to design an algorithm to be used by pharmacists working closely with mental health professionals or who provide care to psychiatric patients.

METHODS

A review of the literature was undertaken. Predefined keywords were used to perform the database search in MEDLINE, EMBASE, and International Pharmaceutical Abstracts to identify reviews, reports and guidelines on the assessment, prevention and monitoring of drug-induced QTc prolongation with an emphasis on psychotropic medications and management in the psychiatric population.

RESULTS

The electronic database search retrieved 637 relevant citations. These were initially screened by title and all duplicates were removed. The abstracts were then reviewed for relevancy based on the inclusion/exclusion criteria. Additional citations were retrieved from the bibliography of the articles identified in the initial search. A total of 79 articles describing QTc prolongation in the psychiatric population were thoroughly examined, but only 31 articles were selected to guide the development of the algorithm.

CONCLUSION

The literature-based algorithm developed provides a stepped-based approach for the assessment, monitoring, and management of drug-induced QTc prolongation in the psychiatric population. The algorithm may assist mental health clinicians in the decision-making process when psychiatric patients are prescribed medications known to increase the QTc interval.

Attitudes about Organ and Tissue Donation among the General Public and Blood Donors in Hong Kong

Context

The cadaveric organ and tissue donation rate in Hong Kong is not satisfactory; 1 million blood donors are registered and more than 300 000 are active. However, the current attitudes toward organ and tissue donation in the general public and blood donors of Hong Kong are unknown.

Methods

Random general public (n = 1018) and blood donors (n = 1227) of Chinese origin, with age ranging from 16 to 60 years, were interviewed using a standard verified questionnaire that examines attitudes and knowledge of organ and tissue donation.

Results

The mean age of the general public and blood donors were 32.6 and 28.9 years, respectively. Of the general public, 44.4% were men and among blood donors, 60% were men. About 56% of both groups thought that organ donation is an obligation of citizens. Blood donors were more aware than the general public about the types of organs that can be donated. When compared with the general public, a significantly higher percentage of blood donors were willing to donate their organs (81% vs 53%), had heard about organ donation cards (98.3% vs 89.5%), and had signed the cards (49.9% vs 22.6%). About 70% of both groups who had signed a card were carrying it. Thirty-nine percent of the general public and 17% of blood donors had not decided whether they would donate. For blood donors, 49.7% were willing to donate their relatives' organs, compared with 41.8% of the general public. Most individuals in both groups would not object to their relatives' decision to donate. About two thirds of individuals in both groups disagreed with the concept of an opt-out law, though only 20% of the general public and 14.4% of blood donors would refuse donation if an opt-out law were in practice.

Conclusions

This study shows that blood donors have better knowledge of organ donation and are more willing to donate their organs and sign an organ donation card than the general public. However, a substantial proportion of blood donors have not signed a donor card. It would be useful to design promotion programs to facilitate blood donors' participation in organ donation.

Level 5 Lymphadenopathy Warrants Heightened Suspicion for Clinically Significant Pathology

We conclude that patients presenting with level 5 lymphadenopathy should be investigated with heightened clinical vigilance. Our results suggest that up to 80 % will harbour clinically significant pathology requiring further medical treatment, three quarters of which will be malignancy. We report an observational study of histological outcomes of level 5 lymph node biopsies from a regional histopathology department across 5 years. 184 subjects were identified as having a biopsy of a lymph node from the level 5 region within the study period. One hundred and fifty six cases (84.8 %) had clinically significant pathology on final histology requiring further medical treatment. Lymphoma accounted for the highest number of cases (n = 72, 39.1 %), followed by metastatic carcinoma (n = 65, 35.3 %) and granulomatous change (n = 17, 9.2 %). Gender and laterality were not shown to be independent predictors of pathology significance (p > 0.05).

Ceramides are associated with inflammatory processes in human mediastinal adipose tissue

BACKGROUND AND AIM

Ceramides are poorly characterized in human adipose tissue. The aim of this study was to investigate concentrations of different ceramide species in human subcutaneous and visceral adipose tissue depots and to determine associations between ceramides and global gene expression profiles.

METHODS AND RESULTS

Concentrations of six ceramide species were determined in plasma and in subcutaneous and mediastinal adipose tissue from 10 overweight subjects (BMI 29.4 ± 4.9 kg/m(2)). In the adipose tissue biopsies gene expression arrays were performed and relationships between ceramides and gene expression analyzed. Immunostaining of the two adipose tissue depots was performed in an independent group of 10 patients. Mediastinal adipose tissue contained significantly higher concentrations (p < 0.05) of all six ceramide species than the subcutaneous depot. Of the six ceramides in plasma, concentrations of only two (Cer d18:1/18:0 and Cer d18:1/22:0) correlated significantly (p < 0.05) with the corresponding species in mediastinal adipose tissue, but there were no significant correlations between ceramides in plasma and subcutaneous adipose tissue. Multivariate analysis identified significant correlations between the total ceramide concentration and global gene expression within mediastinal, but not subcutaneous adipose tissue, according to cross-validation. Gene ontology analysis of genes related to ceramides in the mediastinal depot revealed that genes positively correlated with ceramides were associated mainly with immune and inflammatory categories, while genes negatively correlated with ceramides were associated mainly with lipid and carbohydrate metabolism.

CONCLUSIONS

Ceramides in human mediastinal adipose tissue may be involved in inflammation and lipid and carbohydrate metabolism.

Continuous on-line monitoring of secretion from rodent pituitary endocrine cells using fluorescent protein surrogate markers

We have developed a system to use secreted fluorescent proteins (FPs) as surrogate markers for the continuous on-line monitoring of hormone release from perfused tissue slices. We have tested this system using GH-GFP transgenic rats with green fluorescent protein (GFP) targeted to the secretory vesicles (SVs) of pituitary growth hormone (GH) cells. Brief exposures of vibratome slices to GH secretagogues [GH-releasing hormone (GHRH), GH-releasing peptide-6 (GHRP-6)] or somatostatin caused changes in FP output that correlate with hormone secretion, subsequently measured in fractions of perfusate by radioimmunoassay. The temporal resolution of this method was capable of revealing differences in the kinetics of response to GHRH and GHRP-6 between wild-type and dwarf (dw/dw) rats harbouring the GH-GFP transgene. We further tested the utility of the system by generating transgenic mice with red FPs targeted to secretory vesicles (PRL-mRFP(sv)) and to the cytoplasm (PRL-DsRed(cyto)) of lactotrophs. Dopamine had no effect on the FP output from pituitary slices of PRL-DsRed(cyto) mice but inhibited output from those of PRL-mRFP(sv) animals, with a rebound increase of release after removal, which again correlated with hormone output measured in the perfusate by radioimmunoassay. The inhibition of monomeric RFP secretion by dopamine was dose-dependent, as was stimulation by low concentrations of oxytocin. The temporal resolution afforded by this method provides useful insight into the release kinetics from large populations of pituitary cells, and fills a temporo-spatial gap between single vesicle and single cell monitoring of exocytosis in milliseconds, and in vivo sampling studies of release into the bloodstream on a time scale of minutes.

Three-dimensional ultrasound features of the polycystic ovary in Chinese women

OBJECTIVES

To quantify the three-dimensional (3D) ultrasound characteristics of ovaries in Chinese women with polycystic ovarian syndrome (PCOS) and to compare these with previous data on a Caucasian cohort with PCOS.

METHODS

3D pelvic ultrasound was performed in 40 Chinese women with PCOS and 40 controls. Ovarian volume, stromal volume and echogenicity, and antral follicle count (AFC) were measured and ovarian blood flow was quantified using both 3D power Doppler and two-dimensional (2D) pulsed wave Doppler. These data were compared with previously published data on a Caucasian cohort with PCOS.

RESULTS

Compared with controls, women with PCOS had a higher AFC (median (range), 15 (11-30) vs. 5.5 (1-10) per ovary, P < 0.01), ovarian volume (12.32 (8.10-16.16) mL vs. 5.64 (2.62-8.81) mL, P < 0.01) and stromal volume (9.74 (6.44-13.56) mL vs. 4.07 (1.52-6.67) mL, P < 0.01) but were comparable in stromal echogenicity and ovarian blood flow as measured by 3D power Doppler or 2D pulsed wave Doppler indices. However, in comparison with a previously reported Caucasian cohort with PCOS, the ovaries of Chinese women with PCOS had a significantly smaller stromal volume (median (range), 9.74 (6.44-13.56) mL vs. 10.79 (5.65-17.12) mL, P < 0.05), were less echogenic as reflected in a lower mean gray value (22.43 (13.13-35.50) vs. 32.36 (19.35-53.71), P < 0.01), and had reduced ovarian blood flow as reflected in a lower flow index (30.19 (23.32-44.88) vs. 33.54 (21.88-51.65), P < 0.05).

CONCLUSION

Based on 3D ultrasound measurements, Chinese women with PCOS have an increased stromal volume compared with controls. However, their stromal volume, echogenicity and vascularity is significantly lower than that in Caucasian women with PCOS. The possible etiology for these differences is discussed.

Visible and near-infrared calibrations for quality assessment of fresh phase I and II mushroom (Agaricus bisporus) compost

Previous studies have shown that visible and near-infrared spectra (Vis-NIR) of dry and milled compost can be used for generating partial least squares (PLS) calibrations of phase II compost parameters including ammonia, nitrogen dry matter (NDM), dry matter (DM), pH, conductivity, carbon, microbial population, and potential productivity. The objective of this study was to develop robust calibrations for some of the key parameters from the spectra of fresh phase I and II composts. Samples of substrates from six commercial production yards were obtained during winter and summer months of 2000-2004 to monitor changes in quality and were analyzed for the test factors. Vis-NIR reflectance measurements of fresh samples (740) were made over the range of 400-2500 nm. After mathematical pretreatments, PLS calibrations of the key parameters were developed using the NIR (1100-2500 nm) and visible and NIR (400-2500 nm) regions and subsequently validated using an independent sample set of 123 phase I and II samples obtained during 2004-2005. The phase I and II standard errors of laboratory measurements of ammonia, pH, conductivity, DM, NDM, and ash were lower than the standard error of predictions of the same parameters, respectively, by the best NIR or Vis-NIR models. The degree of precision for some of the calibrations, especially ammonia, NDM, and DM, is suitable for composters to monitor changes in quality parameters during production. The laboratory measurement errors for phase I samples were greater than those of the phase II samples, except for ash, due to a higher degree of heterogeneity in the substrate. The calibrations, especially for pH, conductivity, and ash, need to be improved with new sample sets. A major advantage of NIR spectroscopy is the ability to assess substrate quality for a range of target parameters simultaneously, within a few hours of receiving the samples. The main drawbacks are the expensive instrumentation, expertise, and training necessary for operating the spectrometer and a dedicated chemometrician required for maintaining the equations compared to the reference methods.

Active mobilisation after flexor tendon repair: comparison of results following injuries in zone 2 and other zones

PURPOSE

To prospectively study the role of active mobilisation after flexor tendon repair.

METHODS

The standard modified Kessler's technique was used to repair 46 digits in 32 patients with flexor tendon injuries. Early active mobilisation of the repaired digit was commenced on the third postoperative day. Range of movement was monitored and recovery from injury in zone 2 was compared with injury in other zones.

RESULTS

There were 24 and 22 injuries in zone 2 and other zones respectively. The total active motion score of the American Society for Surgery of the Hand was measured. Patients with zone-2 injuries achieved similar results to those with other-zone injuries apart from a 3-week delay in recovery. The final results were good to excellent in 71% and 77% of zone-2 and other-zone cases respectively (p < 0.05). There were 2 ruptures in zone-2 and one rupture in zone-3 repairs (6.5%).

CONCLUSION

Preliminary results of this study showed that active mobilisation following flexor tendon repair provides comparable clinical results and is as safe as conventional mobilisation programmes although recovery in patients with zone-2 injury was delayed.

TNF and TNFR polymorphisms in severe sepsis and septic shock: a prospective multicentre study

Tumour necrosis factor (TNF) is an important pro-inflammatory cytokine produced in sepsis. Studies examining the association of individual TNF single nucleotide polymorphisms with sepsis have produced conflicting results. This study investigated whether common polymorphisms of the TNF locus and the two receptor genes, TNFRSF1A and TNFRSF1B, influence circulating levels of encoded proteins, and whether individual polymorphisms or extended haplotypes of these genes are associated with susceptibility, severity of illness or outcome in adult patients with severe sepsis or septic shock. A total of 213 Caucasian patients were recruited from eight intensive care units (ICU) in the UK and Australia. Plasma levels of TNF (P = 0.02), sTNFRSF1A (P = 0.005) and sTNFRSF1B (P = 0.01) were significantly higher in those who died on ICU compared to those who survived. There was a positive correlation between increasing soluble receptor levels and organ dysfunction (increasing SOFA score) (sTNFRSF1A R = 0.51, P < 0.001; sTNFRSF1B R = 0.53, P < 0.001), and in particular with the degree of renal dysfunction. In this study, there were no significant associations between the selected candidate TNF or TNF receptor polymorphisms, or their haplotypes, and susceptibility to sepsis, illness severity or outcome. The influence of polymorphisms of the TNF locus on susceptibility to, and outcome from sepsis remains uncertain.

Attitudes about organ and tissue donation among the general public and blood donors in Hong Kong

CONTEXT

The cadaveric organ and tissue donation rate in Hong Kong is not satisfactory; 1 million blood donors are registered and more than 300,000 are active. However, the current attitudes toward organ and tissue donation in the general public and blood donors of Hong Kong are unknown.

METHODS

Random general public (n = 1018) and blood donors (n = 1227) of Chinese origin, with age ranging from 16 to 60 years, were interviewed using a standard verified questionnaire that examines attitudes and knowledge of organ and tissue donation.

RESULTS

The mean age of the general public and blood donors were 32.6 and 28.9 years, respectively. Of the general public, 44.4% were men and among blood donors, 60% were men. About 56% of both groups thought that organ donation is an obligation of citizens. Blood donors were more aware than the general public about the types of organs that can be donated. When compared with the general public, a significantly higher percentage of blood donors were willing to donate their organs (81% vs 53%), had heard about organ donation cards (98.3% vs 89.5%), and had signed the cards (49.9% vs 22.6%). About 70% of both groups who had signed a card were carrying it. Thirty-nine percent of the general public and 17% of blood donors had not decided whether they would donate. For blood donors, 49.7% were willing to donate their relatives' organs, compared with 41.8% of the general public. Most individuals in both groups would not object to their relatives' decision to donate. About two thirds of individuals in both groups disagreed with the concept of an opt-out law, though only 20% of the general public and 14.4% of blood donors would refuse donation if an opt-out law were in practice.

CONCLUSIONS

This study shows that blood donors have better knowledge of organ donation and are more willing to donate their organs and sign an organ donation card than the general public. However, a substantial proportion of blood donors have not signed a donor card. It would be useful to design promotion programs to facilitate blood donors' participation in organ donation.

Different effects of a single amino acid substitution on three adjacent epitopes in the gp41 C-terminal tail of a neutralizing antibody escape mutant of human immunodeficiency virus type 1

The envelope protein of human immunodeficiency virus type 1 (HIV-1) comprises the outer gp 120 SU domain and the anchoring gp41 TM domain, and the conventional view is that it has a single transmembrane region with the following C-terminal sequence situated entirely within the virion. However, we have recently proposed that the gp41 C-terminal region comprises three transmembrane regions and an external loop structure. Part of this loop is the peptide 731PRGPDRPEGIEEEGGERDRDRS752 that carries three antibody epitopes, 734PDRPEG739, 740IEEE743, and 746ERDRD750. PDRPEG is not detected in virions but reacts with its cognate MAb (C8) in Western blots, IEEE is a linear and non-neutralizing epitope, and ERDRD is a conformational and neutralizing epitope. Here we show that escape mutants selected with neutralizing ERDRD-specific antibody had a single 732R-->G substitution, 14 residues upstream of the cognate epitope, and no longer bound the selecting antibody. The same amino acid substitution altered epitope PDRPEG in the virion so that it now reacted with MAb C8, but left epitope IEEE unaffected. Introduction of 732R-->G by site-specific mutagenesis into the gp41 of cloned HIV-1 NL4-3 virions allowed them to escape neutralization by ERDRD-specific IgG, and confirms that 732R makes a major contribution to the neutralizing conformation of the 731-752 region of the C-terminal tail of gp41.

Pecam-1 is a modulator of stat family member phosphorylation and localization: lessons from a transgenic mouse

PECAM-1 (CD31) is a member of the immunoglobin (Ig) superfamily of cell adhesion molecules whose expression is restricted to hematopoietic and vascular cells. PECAM-1 can recruit adapter and signaling molecules via its immunoreceptor tyrosine activation motif (ITAM), suggesting that PECAM-1 plays a role in signal transduction pathways. To study the involvement of PECAM-1 in signaling cascades in vivo, we used the major histocompatibility (MHC) I gene promoter to target ectopic PECAM-1 expression in transgenic mice. We noted an attenuation of mammary gland development at early stages of virgin ductal branching morphogenesis. STAT5a, a modulator of milk protein gene expression during lactation, was localized to the nuclei of ductal epithelial cells of 6-week-old virgin PECAM-1 transgenics, but not in control mice. This correlated with decreases in ductal epithelial cell proliferation and induction of p21, an inhibitor of cell cycle progression. Using in vitro model systems we demonstrated PECAM-1/STAT5a association and found that residue Y701 in PECAM-1's cytoplasmic tail is important for PECAM-1/STAT5 association and that PECAM-1 modulates increases in STAT5a tyrosine phosphorylation levels. We suggest that by serving as a scaffolding, PECAM-1 can bring substrates (STAT5a) and enzymes (a kinase) into close proximity, thereby modulating phosphorylation levels of selected proteins, as previously noted for beta-catenin.

PECAM-1 shedding during apoptosis generates a membrane-anchored truncated molecule with unique signaling characteristics

Shedding of cell surface molecules, including growth factor receptors, provides a mechanism by which cells regulate signal transduction events. Here we show that platelet-endothelial cell adhesion molecule (PECAM)-1 is shed from the endothelial cell surface during apoptosis and accumulates in the culture medium as a approximately 100 kDa soluble protein. The cleavage mediating the shedding is matrix metalloproteinase (MMP) dependent, as GM6001, a broad-spectrum MMP inhibitor, inhibits PECAM-1 accumulation in the culture medium in a dose-responsive manner. In addition to the 100 kDa soluble fragment, PECAM-1 cleavage generates the formation of a truncated (Tr.) approximately 28 kDa molecule, composed of the transmembrane and the cytoplasmic PECAM-1 domains. Transfections of the full-length (Fl) and the Tr. PECAM-1 gene constructs into endothelial and nonendothelial cells were performed. We found 1) significantly more gamma-catenin and SHP-2 bound to the truncated than to the full-length PECAM-1; 2) stable expression of the truncated PECAM-1 in SW480 colon carcinoma cells resulted in a dramatic decrease in cell proliferation, whereas expression of comparable levels of the full-length PECAM-1 had no effect; 3) the decrease observed in cell proliferation is due, in part, to an increase in programmed cell death (apoptosis) and correlated with continuous caspase 8 cleavage and p38/JNK phosphorylation. These results support the intimate involvement of PECAM-1 in signal transduction cascades and also suggest that caspase substrates (e.g., PECAM-1) may possess distinct and unique functions on cleavage.

Bioelectronic detection of point mutations using discrimination of the H63D polymorphism of the Hfe gene as a model

BACKGROUND

A bioelectronic detection platform has recently been developed that facilitates the detection and characterization of nucleic acids. The DNA chip platform is compatible with homogeneous assays because separate labeling and wash steps are not required. A one-step, bioelectronic detection assay was developed to genotype patient samples with respect to the H63D polymorphism of the Hfe gene, associated with hereditary hemochromatosis.

METHODS AND RESULTS

Electrode arrays were modified with DNA capture probes that were perfectly matched to the wild-type or mutant allele of H63D. Amplicons containing the polymorphic site were hybridized with the capture probes on the electrode arrays in the presence of electronically labeled reporter (signaling) probes. Voltammetric analysis of the electrode arrays was conducted first at ambient temperature and then at elevated temperature. The electronic signal was preferentially diminished at elevated temperature from electrodes that hybridized with mismatched target amplicons.

CONCLUSION

An assay for bioelectronic genotyping of the H63D polymorphism was developed and used with six patient specimens to show the feasibility of this system as a model for point mutation detection.

Putative measure of peripheral and brainstem frequency-following in humans

The human brainstem frequency-following response (FFR) registers phase-locked neural activity to periodic auditory stimuli. FFR waveforms were extracted from the electroencephalogram by averaging responses to repeated auditory stimulation. Two channels of data were simultaneously recorded from horizontally (electrodes placed in ear canals) and vertically (vertex scalp referenced to midline) oriented electrode configurations. Eight participants each received a total of 2000 tone repetitions for each of ten stimulus frequencies ranging from 133 to 950 Hz. FFRs were quantified by fast-Fourier spectral analysis. The largest spectral intensities at the stimulus frequency were recorded in the horizontal FFR, which also followed higher frequencies and showed better signal-to-noise ratios then did the vertical FFR. The horizontal FFR pattern suggests an acoustic nerve origin, while the vertical FFR pattern suggests a central brainstem origin.

Platelet-endothelial cell adhesion molecule-1 (CD31), a scaffolding molecule for selected catenin family members whose binding is mediated by different tyrosine and serine/threonine phosphorylation

Platelet-endothelial cell adhesion molecule (PECAM)-1 is a 130-kDa glycoprotein commonly used as an endothelium-specific marker. Evidence to date suggests that PECAM-1 is more than just an endothelial cell marker but is intimately involved in signal transduction pathways. This is mediated in part by phosphorylation of specific tyrosine residues within the ITAM domain of PECAM-1 and by recruitment of adapter and signaling molecules. Recently we demonstrated that PECAM-1/beta-catenin association functions to regulate beta-catenin localization and, moreover, to modulate beta-catenin tyrosine phosphorylation levels. Here we show that: 1) not only beta-catenin, but also gamma-catenin is associated with PECAM-1 in vitro and in vivo; 2) PKC enzyme directly phosphorylates purified PECAM-1; 3) PKC-derived PECAM-1 serine/threonine phosphorylation inversely correlates with gamma-catenin association; 4) PECAM-1 recruits gamma-catenin to cell-cell junctions in transfected SW480 cells; and 5) gamma-catenin may recruit PECAM-1 into an insoluble cytoskeletal fraction. These data further support the concept that PECAM-1 functions as a binder and modulator of catenins and provides a molecular mechanism for previously reported PECAM-1/cytoskeleton interactions.

Magnetic resonance imaging detection of vascular occlusion of a pedicled muscle flap

Contrast-enhanced magnetic resonance imaging (MRI) can be a highly sensitive monitor of tissue blood perfusion. This technique has been used to assess blood flow through liver, kidney, and certain tumors, but has not been widely applied to the study of skeletal muscle circulation. In our study, we used a novel scanning software to obtain contrast-enhanced T2*-weighted gradient echo MRI images of pedicled quadriceps muscle flaps in rabbits in order to study images of arterial, venous, and arterio-venous occlusion. We administered an intravenous bolus of gadoteridol contrast agent at the initiation of scanning, which produces a decrease in T2*-signal and improves the sensitivity of measuring blood perfusion. Within 30 seconds of MRI scanning, control flaps with intact pedicles exhibited a rapid decrease in T2*-signal intensity, indicating adequate perfusion of blood through muscle tissue; however, occluded pedicled flaps showed no significant change in signal intensity, indicating lack of blood perfusion. Differences in signal intensities as measured by MRI between occluded and control flaps were statistically significant (P < 0.05). Selective vascular occlusion of either artery alone, or both artery and vein were detected within 15 minutes, whereas selective venous occlusion could be detected after 2 hours. We conclude that MRI has the ability to assess skeletal muscle perfusion, and is capable of noninvasively evaluating a cross-section of tissue in both superficial and buried flaps. MRI, therefore, may have the potential for evaluating perfusion in muscle flaps (including buried flaps), and other disorders of muscle circulation such as compartment syndrome.

Reproducibility and validity of a food frequency questionnaire among fourth to seventh grade inner-city school children: implications of age and day-to-day variation in dietary intake

OBJECTIVE

To assess the reproducibility and validity of a semiquantitative food frequency questionnaire (FFQ) to classify children and adolescents in terms of daily servings of fruits and vegetables and intake of calories, protein, fat, carbohydrate, dietary fibre, vitamin C, phosphorous, calcium and iron.

DESIGN

FFQs were collected in the autumn of 1993 and 1994. Four 24-hour diet recalls were collected during the same 1-year period and their mean was compared to the FFQ diet estimates.

SETTING

Low income, inner-city state schools.

SUBJECTS

A sample of 109 inner-city fourth to seventh grade students.

RESULTS

The 1-year reproducibility of the FFQ, assessed with Spearman correlations, was lower among the fourth and fifth (range: r=-0.26 to 0.40) than the sixth and seventh grade students (range: r=0.18-0.47). After adjusting for day-to-day variation in dietary intake, for most nutrients and foods the correlations between the FFQ and the 24-hour recalls remained greater among the junior high school students (fourth to fifth grade range: r=0.0-0.42; sixth to seventh grade range: r=0.07-0.76).

CONCLUSIONS

Inner-city sixth and seventh grade students demonstrated the ability to provide valid estimates of intake of calories, carbohydrate, calcium, phosphorous, iron and vitamin C over the past year. However, children in the fourth and fifth grades experienced some difficulty in completing the FFQ. Our results suggest that, before using this instrument with fourth and fifth grade children, investigators should assess whether study participants can think abstractly and are familiar with the concept of 'average intake'.

Insights into the contemporary epidemiology and outpatient management of congestive heart failure

OBJECTIVES

To evaluate the epidemiology, prognosis, and patterns of practice in patients with chronic congestive heart failure (CHF) treated and followed at a specialized clinic.

METHODS

Prospective cohort study of consecutive patients referred to and followed up in a specialized heart failure clinic between September 1989 and March 1996.

RESULTS

Of the 628 patients referred, 566 were confirmed to have CHF. Mean duration of follow-up was 518 +/- 490 days (range 1 to 2192 days). Vital status was available for 99.3% of patients. Mean age at enrollment was 66 years, 68% were men, 67% had an ischemic cause of heart disease, and 78% had systolic dysfunction. Patients with preserved systolic function were older, more often female, had higher mean systolic blood pressures, and a lower prevalence of ischemic heart disease, ventricular arrhythmias, or impaired renal function when compared with those with systolic dysfunction (all P </=.001). Although there was a significant negative trend in survival with decreasing ejection fraction (P =. 03), the survival experience of those with CHF and preserved systolic function did not significantly differ from those with systolic failure (P =.25). Multiple logistic regression analysis showed increased mortality risk was associated with increasing age, New York Heart Association class IV, ischemic cause of disease, elevated serum creatinine level, use of diuretics, and systolic dysfunction, whereas use of beta-blockers was associated with reduced risk.

CONCLUSIONS

Our data suggest that a specialized outpatient clinic can improve practice patterns in patients with CHF. The high mortality risk in CHF with preserved systolic function suggests the need to find efficacious (and effective) therapies for this condition.

Phase I study of 90Y-labeled B72.3 intraperitoneal administration in patients with ovarian cancer: effect of dose and EDTA coadministration on pharmacokinetics and toxicity

The tumor-associated glycoprotein 72 (TAG-72) antigen is present on a high percentage of tumor types including ovarian carcinomas. Antibody B72.3 is a murine monoclonal recognizing the surface domain of the TAG-72 antigen and has been widely used in human clinical trials. After our initial encouraging studies (M. G. Rosenblum et al., J. Natl. Cancer Inst., 83: 1629-1636, 1991) of tissue disposition, metabolism, and pharmacokinetics in 9 patients with ovarian cancer, we designed an escalating dose, multi-arm Phase I study of 90Y-labeled B72.3 i.p. administration. In the first arm of the study, patients (3 pts/dose level) received an i.p. infusion of either 2 or 10 mg of B72.3 labeled with either 1, 10, 15, or 25 mCi of 90Y. Pharmacokinetic studies demonstrated that concentrations of 90Y-labeled B72.3 persist in peritoneal fluid with half-lives >24 h after i.p. administration. In addition, 90Y-labeled B72.3 was absorbed rapidly into the plasma with peak levels achieved within 48 h, and levels declined slowly thereafter. Cumulative urinary excretion of the 90Y label was 10-20% of the administered dose which suggests significant whole-body retention of the radiolabel. Biopsy specimens of bone and marrow obtained at 72 h after administration demonstrated significant content of the label in bone (0.015% of the dose/g) with relatively little in marrow (0.005% of the dose/g). The maximal tolerated dose was determined to be 10 mCi because of hematological toxicity and platelet suppression. This typically occurred on the 29th day after administration and was thought to be a consequence of the irradiation of the marrow from the bony deposition of the radiolabel. In an effort to suppress the bone uptake of 90Y, patients were treated with a continuous i.v. infusion of EDTA (25 mg/kg/12 h x 6) infused immediately before i.p. administration of the radiolabeled antibody. Patients (3 pts/dose level) were treated with doses of 10, 15, 20, 25, 30, 35, 40, or 45 mCi of 90Y-labeled B72.3 for a total of 38 patients. EDTA administration resulted in significant myeloprotection, which allowed escalation to the maximal tolerated dose of 40 mCi. Dose-limiting toxicity was thrombocytopenia and neutropenia. Studies of plasma and peritoneal fluid pharmacokinetics demonstrate no changes compared with patients without EDTA pretreatment. Cumulative urinary excretion of the radiolabel was not increased in patients pretreated with EDTA compared with the untreated group. However, analysis of biopsy specimens of bone and marrow demonstrated that bone and marrow content of the 90Y label was 15-fold lower (<0.001% injected dose/g) than a companion group without EDTA. Four responses were noted in patients who received 15-30 mCi of 90Y-labeled B72.3 with response durations of 1-12 months. These results demonstrate the myeloprotective ability of EDTA, which allows safe i.p. administration of higher doses of 90Y-labeled B72.3 and, therefore, clearly warrant an expanded Phase II trial in patients with minimal residual disease after standard chemotherapy or for the palliation of refractory ascites.

Recombinant immunotoxins directed against the c-erb-2/HER2/neu oncogene product: in vitro cytotoxicity, pharmacokinetics, and in vivo efficacy studies in xenograft models

TAB-250 and BACH-250 are murine and human chimeric antibodies directed at the extracellular domain of the gp185c-erb-2 (HER2/neu) growth factor receptor overexpressed in a variety of tumor types, including ovarian and breast carcinoma. The ribosome-inhibiting plant toxin gelonin (rGel) was chemically coupled to both antibodies, and the resulting immunotoxins were purified and tested in vitro against human tumor cells expressing various levels of HER-2/neu and in vivo against human tumor xenograft models. The binding of both BACH-250 and BACH-250/rGel conjugate to target cells was essentially equivalent. Against SKOV-3 cells, the IC50 of BACH-250/rGel was 97 pM (17 ng/ml), whereas BACH-250 and rGel alone showed no cytotoxic effects. There was a clear correlation between expression levels of HER-2/neu and cytoimmunotoxin. Tissue distribution studies showed that the antibody and immunotoxin both concentrate 2-10-fold higher in tumors than in normal tissues, with optimal tumor uptake occurring 48-96 h after administration. Plasma clearance curves for BACH-250 and BACH-250/rGel showed terminal-phase half-lives of 26 and 72 h, respectively. In athymic mice bearing s.c. or i.p. SKOV-3 tumors, immunotoxin treatment slowed tumor growth by 99 and 94 % at days 35 and 49 after implantation, respectively, and lengthened the median survival by 40% (from 30 to 50 days) in mice bearing lethal i.p. tumors. We conclude that clinical development of BACH-250/rGel may be warranted in patients with HER2/neu-expressing malignancies.

Exposure to the mass media and weight concerns among girls

OBJECTIVE

To assess the influence of the media on girls' weight concerns, weight control/loss behaviors, and perceptions of body weight and shape.

DESIGN

Cross-sectional survey completed in school. The questionnaire assessed body weight, dissatisfaction with body weight and shape, exposure to fashion magazines, the impact of media on feelings about weight and shape, attributes of and preferences for body types, and whether subjects had gone on a diet to lose weight or initiated exercise because of an article in a magazine.

SETTING

Mandatory physical education class in public elementary, junior high, and high schools.

PARTICIPANTS

Subjects included 548 5th- through 12th-grade girls in a working-class suburb in the northeastern United States.

OUTCOME MEASURES

Perceived influence of fashion magazines on body dissatisfaction, idea of the perfect body shape, dieting to lose weight, and initiating an exercise program.

RESULTS

Pictures in magazines had a strong impact on girls' perceptions of their weight and shape. Of the girls, 69% reported that magazine pictures influence their idea of the perfect body shape, and 47% reported wanting to lose weight because of magazine pictures. There was a positive linear association between the frequency of reading women's magazines and the prevalence of having dieted to lose weight because of a magazine article, initiating an exercise program because of a magazine article, wanting to lose weight because of pictures in magazines, and feeling that pictures in magazines influence their idea of the perfect body shape. In multivariate logistic regression models controlling for weight status (overweight vs not overweight), school level (elementary vs junior high school, elementary vs high school), and race/ethnic group, girls who were frequent readers of fashion magazines were two to three times more likely than infrequent readers to diet to lose weight because of a magazine article (odds ratio [OR] = 2.11, 95% confidence interval [CI]: 1.19-3.75); to exercise to lose weight because of a magazine article (OR = 3.02, 95% CI: 1.77-5.17); and to feel that magazines influence what they believe is the ideal body shape (OR = 2.81; 95% CI: 1.72-4.58). In addition, moderate-frequency readers were more likely than infrequent readers of fashion magazines to report exercising because of a magazine article (OR = 1.94; 95% CI: 1.14-3.30) and feeling that magazines influence what they believe is the ideal body shape (OR = 2.03; 95% CI: 1.30-3.15).

DISCUSSION

The majority of the preadolescent and adolescent girls in this school-based study were unhappy with their body weight and shape. This discontentment was strongly related to the frequency of reading fashion magazines. Although previous studies have concluded that the print media promotes an unrealistically thin body ideal, which in turn is at least partially responsible for promoting eating disorders, the present study is the first that we are aware of to assess directly the impact of the print media on the weight and body shape beliefs of young girls. We observed that the frequency of reading fashion magazines was positively associated with the prevalence of having dieted to lose weight, having gone on a diet because of a magazine article, exercising to lose weight or improve body shape, and deciding to exercise because of a magazine article. Given the substantial health risk associated with overweight and the fact that during the past 2 decades the prevalence of overweight has increased sharply among children and adolescents, it is not prudent to suggest that overweight girls should accept their body shape and not be encouraged to lose weight. However, aspiring to look like underweight models may have deleterious psychological consequences. The results suggest that the print media aimed at young girls could serve a public health role by refraining from relying on models who are severely underweight and printing more articles on the benefits of physical

Determination of blood flow in the finger using near-infrared spectroscopy

Wavelengths in the near-infrared range have much better penetrance in organic substances than visible light. We used near-infrared spectroscopy to determine non-invasively blood flow in the fingertip. We used laser Doppler technology to measure skin blood flow as a comparison procedure. We performed several manoeuvres to change blood flow. These included restriction of flow, thermal stimulation and post-occlusion hyperaemia. Near-infrared measurements had coefficients of variation of 10-15% at the various wavelengths, contrasting with variability of 30-40% with laser Doppler measurement. With restriction of blood flow, there was a downward shift in the absorbance curve. With thermal stimulation and with post-occlusion hyperaemia, there was a rise in the curve. The flow-induced shifts in the absorbance curve were particularly pronounced in the range of 850-970 nm. The correlation between absorbance values and laser Doppler-determined blood flow was also highest in this range, averaging about 0.69 (n = 625). Near-infrared spectroscopy can therefore be used to scan the fingertip. The absorbances obtained do reflect changes in blood flow. There is a correlation with skin blood flow, although near-infrared measurements are affected by blood flow in the full breadth of the finger, not just the skin. We can measure this blood flow with significant reproducibility. It may be possible to use near-infrared spectroscopy to measure the concentration of individual blood components.

Spiral spin-echo magnetic resonance imaging of the pelvis with spectrally and spatially selective radiofrequency excitation: comparison with fat-saturated fast spin-echo imaging

OBJECTIVE

The authors describe their initial clinical experience in comparing a spiral spin-echo technique with a fat-saturated fast spin-echo technique for imaging the pelvis.

METHODS

A total of 18 patients were imaged with both spiral spin-echo and fat-saturated fast spin-echo magnetic resonance imaging. The spiral spin-echo technique combines a spectrally and spatially selective radiofrequency excitation with a spiral k-space trajectory. This technique permits rapid acquisition of T2-weighted water-only images.

RESULTS

The spiral spin-echo images were judged superior to the fat-saturated fast spin-echo images in terms of uniformity of fat suppression and absence of flow-related artifacts. However, the overall image quality of the spiral spin-echo images was inferior to that of the fat-saturated fast spin-echo images, as a result of blurring caused by off resonance effects. The two techniques were judged equivalent in terms of conspicuity of the abnormality and diagnostic information.

CONCLUSION

The authors conclude that the spiral spin-echo technique holds promise, particularly if combined with a deblurring algorithm.

DNA testing in familial hypertrophic cardiomyopathy: clinical and laboratory implications

Counselling and clinical assessment in familial hypertrophic cardiomyopathy (FHC) is difficult, particularly in the young, since echocardiographic and ECG changes may not be diagnostic and clinical severity can vary. From 1990, when the beta-cardiac myosin heavy chain gene was implicated in the aetiology of FHC, considerable information about the molecular genetics of this disorder has emerged. However, an important question facing health professionals is the practical significance of DNA testing in FHC. The present study describes a DNA-based approach to screening for five commonly reported mutations involving the beta-cardiac myosin heavy chain gene. Approximately 11% of randomly selected families had an abnormality detected.

Effect of human immunodeficiency virus on hepatitis C virus infection among injecting drug users

To assess the effect of human immunodeficiency virus (HIV) immunosuppression on ongoing hepatitis C virus (HCV) infection, CD4 lymphocyte counts and serum concentrations of HCV RNA, HIV RNA, and alanine aminotransferase (ALT) were evaluated among members of a cohort of injecting drug users (IDUs). With 100 participants randomly selected at various stages of HIV-related immunosuppression, serum HCV RNA concentrations increased with age (P = .007) and were higher in HIV-positive IDUs with 201-500 (P = .026) and 51-200 (P = .004) CD4 cells/mL than in HIV-negative participants. Among 27 HCV-infected IDUs who acquired HIV infection, serum HCV RNA concentrations varied between semiannual visits by a mean of 0.45 logs, increasing by 0.60 logs after HIV seroconversion (P < .0001), by 0.12 logs each subsequent year (P = .006), and by 0.36 logs per log increase in CD4 cells (P = .01). Serum ALT levels were similar between HIV-positive (40.1 IU/mL) and HIV-negative (45.4 IU/mL) patients (P > .10). While HIV infection and possibly HIV progression are associated with increased HCV RNA levels, other factors appear to affect biochemical and virologic markers of HCV infection in some dually infected persons.

Routes of infection, viremia, and liver disease in blood donors found to have hepatitis C virus infection

BACKGROUND

For many people infected with the hepatitis C virus (HCV), the route of exposure, risk of transmission, and severity of associated liver disease are unknown. We studied these variables in people who donated blood voluntarily.

METHODS

Blood donors who tested positive for HCV antibodies on enzyme immunoassay were classified according to whether the results of a confirmatory second-generation recombinant immunoblot assay (RIBA) for HCV were positive, negative, or indeterminate. The evaluations also included an assessment of risk factors, a physical examination, serial determinations of alanine aminotransferase levels and HCV serologic assays, a polymerase-chain-reaction assay for HCV RNA, testing of sexual contacts and family members, and liver biopsies in some participants who were HCV-positive by RIBA.

RESULTS

A total of 481 donors were studied, among whom 248 were positive for HCV by RIBA, 102 had indeterminate results, and 131 were HCV-negative. In a logistic-regression analysis, significant risk factors for HCV infection among the HCV-positive participants were a history of blood transfusion in 66 (27 percent; P < 0.001 for the comparison with RIBA-negative donors), intranasal cocaine use in 169 (68 percent, P < 0.001), intravenous drug use in 103 (42 percent, P = 0.001), sexual promiscuity in 132 (53 percent, P = 0.002), and ear piercing among men (P < 0.05). Nine of 85 sexual partners of HCV-positive donors were anti-HCV-positive; 8 had used intravenous drugs or received transfusions. HCV RNA was found in 213 HCV-positive donors (86 percent), 3 who had indeterminate results by RIBA (2 of these 3 tested positive with a more specific, third-generation RIBA), and none who were HCV-negative. Of the HCV-positive donors, 69 percent had biochemical evidence of chronic liver disease; among 77 donors positive for HCV by RIBA who underwent liver biopsy, 5 had severe chronic hepatitis or cirrhosis, 66 had mild-to-moderate chronic hepatitis, and 6 had no evidence of hepatitis.

CONCLUSIONS

Among volunteer blood donors, prior blood transfusion, intranasal cocaine use, intravenous drug use, sexual promiscuity, and ear piercing in men are risk factors for HCV infection. The high frequency of intravenous drug use was unexpected, because these donors had denied such use when questioned directly at the time of their blood donations.

Cellular resistance to the antimelanoma immunotoxin ZME-gelonin and strategies to target resistant cells

The development of cellular resistance to immunotoxins has been demonstrated in a variety of models and can involve a number of mechanisms. For the present study, an immunotoxin was utilized composed of an anti-melanoma antibody ZME-018 recognizing a 240-kDa surface glycoprotein (gp 240) and the plant toxin gelonin. Human melanoma cells (A375-M) were grown in the presence of increasing amounts of ZME-gelonin and a clonal variant (A-375-ZR) was developed that was 100-fold resistant to ZME-gelonin compared to parental cells. Scatchard analysis showed that the A375-M parental cells had 260 X 10(3) ZME-gelonin-binding sites/cell with relatively low affinity (5 nM). In contrast, resistant A375-ZR cells demonstrated a reduced number of low-affinity sites (160 x 10(3)/cel1), but showed a small number (47 x 10(3)) of higher-affinity sites (0.8 nM). Internalization rates and degradation rates of 125I-labeled ZME-gelonin were identical in both the parental and resistant cells. A375-ZR cells were found to be more resistant to vincristine and doxorubicin than were parental cells. Both cell lines were almost equally sensitive to native gelonin, 5-fluorouracil (5-FU), cisplatin. melphalan, carmustine, interferon gamma (IFNgamma) and IFNalpha. In addition. both cell lines were equally sensitive to another gelonin antibody conjugate that binds to cell-surface, GD2 (antibody 14G2A). However, resistant cells were twice as sensitive to the cytotoxic effects of etoposide than were parental cells. Finally, a variety of agents were tested in combination with ZME-gelonin against A375-ZR cells in an attempt to identify agents to augment immunotoxin cytotoxic effects against resistant cells. The agents 5-FU, cisplatin, IFNgamma, IFNalpha, and etoposide were the most effective in augmenting the cytotoxicity of ZME-gelonin against resistant cells. These studies suggest that development of resistance to one immunotoxin does not cause development of cross-resistance to other gelonin immunotoxins. Further, specific biological response modifiers and chemotherapeutic agents may be effective in augmenting the effectiveness of immunotoxins and specifically targeting or reducing the emergence of immunotoxin-resistant cells.

Amino acid sequence analysis, gene construction, cloning, and expression of gelonin, a toxin derived from Gelonium multiflorum

The plant toxin gelonin is an extremely potent inhibitor of protein synthesis, similar in action to ricin. The mature protein primary sequence was obtained using conventional sequencing techniques. Gelonin was found to be composed of 258 amino acids and contains 21 lysine residues. This toxin shares approximately 33% sequence homology with trichosanthin and ricin A chain. A 774 bp synthetic gene encoding gelonin was synthesized and expressed in E. coli. Recombinant gelonin (approximately 28 kD) expression was monitored and demonstrated by western analysis. Purification and functional activity studies demonstrated that this protein behaves identically to that of the natural product. Recombinant gelonin (RG) thus joins a growing list of recombinant toxins currently available for use in the construction of recombinant immunotoxins composed of gelonin fused to binding domains of antibodies, growth factors, or other cytokines.

Pharmacokinetics, tissue distribution, and in vivo antitumor effects of the antimelanoma immunotoxin ZME-gelonin

Antibody ZME-018 is directed against the gp240 glycoprotein on the surface of more than 80% of human melanoma cell lines and fresh biopsy specimens. Previous studies in our laboratory described the in vitro cytotoxicity and specificity of an immunoconjugate composed of mAb ZME-018 and the plant toxin gelonin. The present study described the in vivo pharmacokinetics and therapeutic effects of ZME-gelonin in human xenograft/nude mouse models. Pharmacokinetic studies of 125I-labeled ZME-018 and ZME-gelonin demonstrated a shorter terminal-phase plasma half-life of the immunoconjugate than native ZME (20.6 h compared to 41.3 h). The initial volume of distribution of the ZME-gelonin was also higher compared to that of ZME alone (2.85 ml compared to 1.94 ml) suggesting an enhanced distribution of the conjugate outside the vasculature. The corresponding area under the concentration/time curve for the ZME-gelonin conjugate was 40% lower than that of ZME alone (80.8 compared to 139.6 microCi.ml-1 x min). In nude mice bearing well-developed human tumor A375 melanoma xenografts, administration of 125I-labeled ZME and ZME-gelonin resulted in tumor-to-blood ratios of 1.9 +/- 0.5 and 1.5 +/- 0.6 respectively by 72 h. Compared with ZME, ZME-gelonin conjugate caused an increase in the content of radiolabel in kidney, spleen and liver. Treatment of nude mice bearing well-developed (150 mm3) s.c. A375-M xenografts with divided doses of ZME-gelonin, ZME, gelonin, or saline resulted in suppression of tumor growth in the immunotoxin group but virtually no retardation of tumor growth in the control groups. Using a murine model for a rapidly growing lethal metastatic human melanoma, treatment with ZME-gelonin resulted in a mean survival of 44 days, 213% increase in mean survival time compared with the saline treatment (14.2 +/- 2 day survival). Given these encouraging results, we are proceeding with further preclinical development of this immunotoxin.