Light-Sensitive Ruthenium Complex-Loaded Cross-linked Polymeric Nanoassemblies for the Treatment of Cancer.

This work focuses on improving the efficacy of photoactivatable Ru complexes for photodynamic therapy by employing cross-linked nanoassemblies (CNAs) as a delivery approach. The effects of complex photoactivation, hydrophobicity, and solution ionic strength and pH on complex loading and release from CNAs were analyzed. The cell cytotoxicity of CNA formulations was similar to free Ru complexes despite reduced or eliminated DNA interactions. The release rate and the amount of each Ru complex released (%) varied inversely with complex hydrophobicity, while the effect of solution ionic strength was dependent on complex hydrophobicity. Premature release of two photoactivatable prodrugs prior to irradiation was believed to account for higher activity in cells studies compared to DNA interaction studies; however, for photostable 1O2 generator-loaded CNAs this cannot explain the high cytotoxicity and lack of DNA interactions because release was incomplete after 48 hrs. The cause remains unclear, but among other possibilities, accelerated release in a cell culture environment may be responsible.

Velocity scaling of a shock wave reflected off a circular cylinder.

Two different approaches are undertaken to investigate the interaction of planar shock waves with circular cylinders. Experiments are conducted in a shock-tube apparatus equipped with a schlieren-based optical system to monitor the interaction, and numerical simulations are carried out using an in-house computer code to simulate similar problems. The incident shock-wave Mach number is varied in the range 1.1-1.4. Excellent agreement is found between the simulations and the experiments in terms of shock patterns, even though the model is based on an inviscid approach. Quantitative comparisons between the experimental results for different initial conditions (shock-wave strength, cylinder diameter, and working gas) are made to find the physical parameters affecting the path of the reflected shock. An approximate universal relation is derived, which predicts the reflected-shock trajectory along the axis of symmetry as a function of the incident-shock Mach, the diameter of the cylinder, and the gas properties. This relation is valid in the vicinity of the cylinder in the range of 0.1-5 D, where D is the cylinder diameter. It is found that the reflected shock from the cylinder evolves as in the case of a reflected-shock wave from a planar wall multiplied by a reduction factor, which depends on the incident-shock Mach number and the ratio of specific heats.

Cancer among Hispanic children in California, 1988-1994: comparison with non-Hispanic white children.

BACKGROUND: There has been a perception that California Hispanic children have an unusually high cancer incidence rate, but to the authors' knowledge the only information regarding cancer rates in this population has been the tabular data published in reports issued by the California Department of Health Services. The California Cancer Registry has collected data regarding all cancers diagnosed in California since 1988. METHODS: Data regarding all invasive cancers diagnosed in California Hispanic children age <15 years during the 7-year period 1988-1994 were analyzed. Cancers were grouped according to the International Classification for Childhood Cancers. Age-adjusted and age specific incidence rates were compared with the corresponding incidence rates among non-Hispanic white children. RESULTS: Based on available demographic information, the overall incidence rate of cancer was approximately 7% lower among California children classified as Hispanic than among non-Hispanic white children. Hispanic children had higher incidence rates of lymphoid leukemia and gonadal germ cell tumors and a lower incidence rate of astrocytomas and carcinomas than non-Hispanic white children. CONCLUSIONS: These data do not confirm the perception that California Hispanic children have an unusually high cancer incidence rate but there were notable differences between Hispanic and non-Hispanic white children with regard to the incidence rates of certain cancers. The perception may be due in part to the fact that childhood malignancies represented 3.1% of all cancers diagnosed among Hispanics but only 0.5% of all cancers diagnosed among non-Hispanic whites. This is explained by the lower incidence rate of cancer among California Hispanic adults than among non-Hispanic white adults and the difference in the age distribution of the two populations.

Repromicin derivatives with potent antibacterial activity against Pasteurella multocida.

Reductive amination of repromicin with polyfunctional amines has led to new macrolide antibacterial agents, some of which are highly potent against the Gram-negative pathogen Pasteurella multocida both in vitro and in a mouse infection model. A key element in this discovery was the recognition that among certain known macrolides increasing lipophilicity results in diminished in vivo activity. One repromicin derivative, 20-[N-[3-(dimethylamino)-propyl]-N-L-alanylamino]-20-deoxorepro micin (35), was selected for advanced evaluation. At 5 mg/kg, a single subcutaneous dose was found to control induced pasteurellosis in swine and induced respiratory disease in cattle.

Influence of graded changes in vasomotor tone on the carotid arterial mechanics in live spontaneously hypertensive rats.

1. The contribution of vasomotor tone to the increased stiffness of carotid arteries in living spontaneously hypertensive rats (SHR) is largely unknown. Whether a reduced vascular tone is associated with an increase or a decrease in arterial stiffness in vivo remains to be determined. The goal of the present investigation was to show that a decrease in vascular tone is associated with a decrease in arterial stiffness, independent of the structural composition of the arterial wall. 2. New high resolution echo-tracking techniques were used to evaluate pulsatile changes of carotid blood pressure and diameter following transient and graded changes of vasomotor tone produced by the dihydropyridine derivative, isradipine. Treatment for 8 weeks was given to groups of SHR rats either with a low (0.6 kg day-1) or a high (2.6 mg kg-1 day-1) dose. Another SHR group received an acute dose of 2.6 mg kg-1 day-1. Results were compared to those of placebo-treated Wystar-Kyoto (WKY) and SHR rats. Whatever the dosage, acute or chronic calcium blockade caused a decrease in blood pressure which was maximal 1 h after administration and disappeared after the 16th h. Carotid arterial thickness and the composition of the arterial wall was determined from histomorphometry. 3. In placebo-treated SHR, the inverse relationship relating blood pressure to carotid arterial distensibility was significantly shifted toward higher values of blood pressure compared to the curve of normotensive placebo-treated WKY rats. The curve of SHR receiving chronically a non antihypertensive (0.6 mg kg-1 day-1) isradipine dose prolonged that of placebo-treated SHR toward lower values of blood pressure, so that carotid distensibility was significantly higher than in WKY for the same diameter and blood pressure level (145 mmHg). With administration of a chronic antihypertensive dose (2.6 mg kg-1 day-1) causing a significant decrease in arterial function. Acute antihypertensive calcium blockade with a single isradipine dose (2.6 mg kg-1 day-1) caused a similar shift in the pressure-distensibility curve toward the WKY curve although the histomorphometric composition of the arterial wall differed significantly from that of chronically treated animals. 4. The study provides evidence that, in living SHR submitted to calcium blockade, (i) a low dose of isradipine causing no substantial antihypertensive effect is associated with a significant elevation of carotid arterial distensibility for the same pressure and diameter as normotensive controls, and (ii) an acute or chronic dose causing a substantial antihypertensive effect is associated with a transient shift of the SHR distensibility-pressure curve toward a physiological arterial function, increasing carotid distensibility for the same pressure and diameter as WKY controls. Since such findings were observed independently of the histomorphometric composition of the arterial wall, they imply that the transient decrease in arterial stiffness produced by calcium blockade should involve specific changes in the connections between arterial smooth muscle and extracellular matrix.

Complex processing and protein:protein interactions in the E2:NS2 region of HCV.

Hepatitis C virus (HCV), the principal cause of parenteral non-A, non-B hepatitis, is an RNA virus and a member of the Flaviviridae family. Its genome is translated into a single polyprotein that is processed co- and post-translationally into both structural and nonstructural (NS) proteins. There are three putative structural proteins, consisting of the nucleocapsid protein and two envelope glycoproteins, E1 and E2. Analysis of transient transfections of serially extended templates covering the E2/NS2 region provided evidence for three E2 species with distinct C-termini. One form is E2 terminating at amino acid 729, while the larger two species represent fusions with the downstream NS2A and NS2A/NS2B proteins terminating at amino acids 809 and 1026, respectively. Using the same E2 templates, we defined a region of E2 important for co-immunoprecipitation of E1 and observed that this region also prevents E2 secretion. The N-terminus of NS2B was determined by radiosequencing and a novel association of NS2B and probable NS4B with E2 was observed; the regions of NS2B and E2 important for this association have been mapped. These data indicate that complex processing and protein:protein interactions occur during HCV morphogenesis.

Expression, identification and subcellular localization of the proteins encoded by the hepatitis C viral genome.

We have expressed the full-length coding region and selected domains of the hepatitis C virus (HCV) cDNA in mammalian cells by transfection. Using HCV antibody-positive human sera and monospecific antibodies the proteins encoded by the putative structural and non-structural regions of the open reading frame of HCV were identified as core (p22), E1 (gp32-35), E2 (gp68-72), NS2 (p23), NS3 (p72), NS4a and b (p10 and p27) and NS5a and b (p56 and p70). We have also defined the subcellular localizations of the HCV proteins using indirect immunofluorescence assays.

The value of ultrasound in the diagnosis of congenital hypertrophic pyloric stenosis.

The charts of 103 children with a clinically and surgically confirmed diagnosis of congenital hypertrophic pyloric stenosis were retrospectively reviewed. We found a significant correlation between sonographic and surgical measurements of the muscular thickness of the pylorus (r = .987, P < .001). In 73.7% (76 cases), the clinical picture of gastric outlet obstruction was present when the thickness of the enlarged pyloric muscle was 3.0 mm or more. In 26.3% (27 cases), the pyloric muscle was less than 3.0 mm wide. For 10 patients in whom the muscle width was less than 2.5 mm by sonography, a barium meal was necessary to confirm the diagnosis. The width of the pyloric muscle is the most important factor in the sonographic diagnosis of pyloric stenosis, and even a width of less than 3.0 mm may be associated with clinically significant obstruction.

CP-72,588, a semisynthetic analog of the polyether ionophore UK-58,582 with increased anticoccidial potency.

We have employed semisynthesis to enhance the anticoccidial potency of a polyether ionophore. CP-72,588 is the alpha-methyl analog of the fermentation-derived polyether ionophore UK-58,852. The parent ionophore required a dose of 15 ppm to achieve anticoccidial efficacy in chickens equivalent to that of salinomycin at 60 ppm. CP-72,588 demonstrated substantially improved potency, with efficacy at 5 to 7.5 ppm. The intrinsic antimicrobial potencies of the two ionophores are similar; however, CP-72,588 was found in chicken tissues at higher levels than those of the parent ionophore when each was administered at the same dose (8 ppm). The enhanced potency of CP-72,588 may be partially due to enhanced uptake into tissues.

Modulation of myeloid proliferation and differentiation by monoclonal antibodies directed against a protein that interacts with the interleukin-3 receptor.

Hematopoietic cells can be transformed through the acquisition of autocrine growth factor production. Because of their ability to inhibit autocrine growth, antibodies directed against the growth factor or its receptor may have therapeutic potential. However, these agents may also inhibit normal cell development. We have developed two monoclonal antibodies, 4G8 and 2F2, directed against a protein of 110 to 150 Kd that interacts with the interleukin-3 (IL-3) receptor (R) complex. These antibodies inhibit IL-3-induced proliferation of nonleukemic and leukemic IL-3-dependent cell lines, as well as the autonomous growth of WEHI-3B in vitro and in vivo. These results suggest the possibility that anti-IL-3R antibodies may be useful in the treatment of some leukemias. However, the effect of anti-IL-3R antibodies on normal myeloid development in vitro has not been examined. We examined the effect of 4G8 and 2F2 on the growth in vitro of colony-forming unit granulocyte-macrophage (CFU-GM) colonies induced by IL-3, granulocyte colony-stimulating factor (G-CSF), granulocyte-macrophage CSF (GM-CSF), and macrophage-CSF (M-CSF). Our results show that while 4G8 and 2F2 inhibited CFU-GM colony formation induced by IL-3, they augmented colony formation induced by the other hematopoietins. 4G8 and 2F2 also enhanced G-CSF-induced proliferation of 32Dc13 and GM-CSF-induced proliferation of PT18, confirming that the effect on CFU-GM was a direct effect. Finally, 4G8 and 2F2 inhibited G-CSF-induced differentiation of 32Dc13, similar to low levels of IL-3; yet, neither 4G8 nor 2F2 blocked binding of G-CSF to its receptor. These results indicate that, in the absence of IL-3 and in the presence of other hematopoietins, 4G8 and 2F2 can function as weak IL-3 agonists. These studies suggest that antibodies such as 4G8 and 2F2, directed against components of the IL-3R, could potentially augment myeloid growth in vivo, rather than inhibit myeloid growth.

Synthetic modification of a novel microbial ionophore: exploration of anticoccidial structure-activity relationships.

While fermentation-derived polyether ionophores such as salinomycin are the dominant class of anticoccidial feed additives, there is little information concerning the structural features which confer optimal potency/efficacy in this important series. The recently discovered microbial polyether 1a, featuring potent, broad-spectrum anticoccidial activity, was employed as a template to explore structure-activity relationships. A number of single-step synthetic modifications targeted structural changes in both the lipophilic carbon backbone and the ion-binding cavity of 1a. Although previous semisynthetic transformations among the polyether ionophores almost always resulted in a substantial loss of anticoccidial activity, we obtained several analogues, altered on the periphery of the ionophore-ion complex, which retain good potency and efficacy. Monoglycone 7 (semduramicin sodium) has the most impressive anticoccidial profile of this series, and is undergoing further biological testing under field conditions.

Anticoccidial activities of 7-bromo-N-(2-imidazolidinylidene)-1H-indazol-6-amine and other alpha 2 adrenergic agonists.

Activity against the coccidial pathogen Eimeria tenella in chickens has been discovered among alpha 2 adrenergic agonists. The clonidine analog 7-bromo-N-(2-imidazolidinylidene)-1H-indazol-6-amine was active in feed at 7.5 ppm, a concentration similar to the use levels of potent commercial agents, e.g., maduramicin. Additional alpha 2 agonists were also found to have anticoccidial activity, for example, the catecholamine nordefrin, which is chemically unrelated to clonidine. However, alpha 1 agonists and alpha antagonists were inactive. These observations imply that anticoccidial effects reflect involvement of a receptor with the characteristics of the vertebrate alpha 2 adrenoceptor. alpha 2 agonists that permeate the blood-brain barrier (like clonidine) inhibit feed intake at efficacious levels, whereas those that are restricted to the peripheral compartment (such as catecholamines) do not inhibit feed intake as much. Hence, anticoccidial efficacy may be a peripheral adrenergic effect whereas depression of feed intake is likely centrally mediated.

Anticoccidial efficacy of semduramicin in battery studies with laboratory isolates of coccidia.

The anticoccidial activity of semduramicin against laboratory isolates of five species of poultry Eimeria was investigated. In laboratory scale battery trials, semduramicin at 20 to 30 ppm demonstrated broad-spectrum anticoccidial efficacy equivalent to salinomycin at 60 ppm. Also, semduramicin at 25 ppm was fed to uninfected cockerels in batteries for 21 days, and growth rate and feed efficiency were found to be equivalent to birds fed salinomycin at 60 ppm. Semduramicin was well tolerated when coadministered with tiamulin. Semduramicin demonstrated the same activity whether produced by semisynthesis or by direct fermentation.

Modulation by tumor necrosis factor-alpha of human astroglial cell production of granulocyte-macrophage colony-stimulating factor (GM-CSF) and granulocyte colony-stimulating factor (G-CSF).

Phagocyte survival and function are enhanced by GM-CSF and G-CSF. The production of both CSFs can be induced in mesenchymal cells by tumor necrosis factor-alpha (TNF-alpha) and interleukin-1 (IL-1). We have recently demonstrated that IL-1 alpha and beta induced the production of GM-CSF and G-CSF by two human astroglial cell lines. In the present study, we examined the effects of TNF-alpha on the production of GM-CSF and G-CSF by U87MG, a human astroglial cell line that constitutively expresses GM-CSF and G-CSF, and U373MG, a second human astroglial cell line that does not produce CSF. We demonstrate that U87MG can be induced to increase its production of GM-CSF and G-CSF by exposure to TNF-alpha while U373MG is induced to produce GM-CSF but not G-CSF. These responses, measured by accumulation of elevated levels of CSF protein and mRNA, are rapid and sensitive. The implications of these findings to the immunopathogenesis of central nervous system infections are discussed.

Comparisons of diet and biochemical characteristics of stool and urine between Chinese populations with low and high colorectal cancer rates.

In an investigation of the roles of diet and stool biochemistry in human colorectal carcinogenesis, 24-hour food, urine, and stool samples were collected from randomly selected participants from two populations with a fourfold difference in colorectal cancer risk: Chinese in Sha Giao, People's Republic of China (low risk), and Chinese-Americans of similar ages in San Francisco County, Calif, in the United States (high risk). The findings supported the hypotheses that colorectal cancer risk is increased by the consumption of high-fat, high-protein, and low-carbohydrate diets and is associated with high levels of cholesterol in stool as well as increased daily outputs of 3-methyl-histidine and malonaldehyde in urine. However, risk does not increase with low stool bulk and low total stool fibers.

Monokine modulation of human astroglial cell production of granulocyte colony-stimulating factor and granulocyte-macrophage colony-stimulating factor. I. Effects of IL-1 alpha and IL-beta.

Granulocyte (G)-CSF and granulocyte-macrophage (GM)-CSF enhance phagocyte survival and function and are produced by fibroblasts and endothelial cells after induction by inflammatory mediators such as IL-1. Our ability to detect G-CSF and GM-CSF activity in the conditioned medium of the human astroglial tumor cell line, U87MG, and molecularly clone the cDNA for G-CSF from a U87MG cDNA library raised the possibility that astroglial cells are capable of G-CSF and GM-CSF production within the central nervous system; if so, the production of these CSF by astroglial cells may be inducible by IL-1. We examined the effects of IL-1 alpha and IL-1 beta on the production of G-CSF and GM-CSF by U87MG and U373MG, another astroglial tumor cell line that does not constitutively produce CSF. We demonstrate that both U87MG and U373MG can be induced to produce G-CSF and GM-CSF by exposure to IL-1 alpha and IL-1 beta. This response, measured by accumulation of increased CSF mRNA, is rapid, sensitive and due to the enhanced stability of CSF message following IL-1 exposure. The implications of these findings to the immunopathogenesis of central nervous system infections are discussed.

Assessment of potential for cancer control by Golden State Medical Association physicians.

To gather data on which to base the design of an intervention program to decrease cancer mortality in the black population of California, physician members of the Golden State Medical Association were surveyed to determine their current practices relating to early cancer detection and cancer prevention. Respondents' estimates of the proportions of their patients in various categories indicated that at least 60% to 70% of their patients were potential subjects for intensive early cancer detection and cancer prevention efforts. Thirty-four percent of respondents reported that they were performing early cancer detection examinations on all their patients. On the average, respondents estimated that about 70% of their patients (more than 80% of patients of primary care physicians) were receiving either routine check-ups or specific early cancer detection examinations. Patient education about various aspects of cancer and cancer prevention emerged as the most readily attainable means to reduce cancer mortality in blacks. It was most frequently mentioned both as something that physicians could do to help achieve this goal and as an outside resource physicians would find useful in their practices. Its lack was cited as the greatest barrier to early cancer detection and cancer prevention in the black population.

Utilization and effectiveness of a hospital autologous preoperative blood donor program.

The utilization and effectiveness of a hospital preoperative autologous blood donation program were analyzed. Over 16 months, 180 donors, or 11.6 percent of eligible patients (those undergoing elective surgical procedures where blood was routinely crossmatched), were enrolled in the program. They donated an average of 2.2 units of red cells, or 59 percent of the mean order of 3.7 units. Donations were completed in 17.9 days, leaving 10.7 days between the last donation and hospitalization. Of all scheduled donations, 25.5 percent were cancelled due to deferrals; 47.8 percent of patients were deferred at least once. Most patients were able to donate a unit of blood weekly, with minimal drops in hematocrit (mean 3.2%). The reaction rate, 4.8 percent, was comparable to figures reported for homologous donors. Nearly two-thirds of participants used no homologous blood during their hospitalization: 28.6 percent used no blood whatsoever, and 36.9 percent used only autologous components. Including released autologous components subsequently administered to other recipients, transfused autologous red cells were 2.1 percent and fresh-frozen plasma (FFP) 7.2 percent of the hospital's blood supply. Although the high deferral rate complicated the administration of the program, this complication was offset by the demonstration of donor safety, reduction in the proportion of patients who used homologous blood, and the contribution of autologous blood components to the hospital's blood inventory.