Spontaneous dormancy of metastatic breast cancer cells in an all human liver microphysiologic system.

BACKGROUND: Metastatic outgrowth in breast cancer can occur years after a seeming cure. Existing model systems of dormancy are limited as they do not recapitulate human metastatic dormancy without exogenous manipulations and are unable to query early events of micrometastases. METHODS: Here, we describe a human ex vivo hepatic microphysiologic system. The system is established with fresh human hepatocytes and non-parenchymal cells (NPCs) creating a microenvironment into which breast cancer cells (MCF7 and MDA-MB-231) are added. RESULTS: The hepatic tissue maintains function through 15 days as verified by liver-specific protein production and drug metabolism assays. The NPCs form an integral part of the hepatic niche, demonstrated within the system through their participation in differential signalling cascades and cancer cell outcomes. Breast cancer cells intercalate into the hepatic niche without interfering with hepatocyte function. Examination of cancer cells demonstrated that a significant subset enter a quiescent state of dormancy as shown by lack of cell cycling (EdU(-) or Ki67(-)). The presence of NPCs altered the cancer cell fraction entering quiescence, and lead to differential cytokine profiles in the microenvironment effluent. CONCLUSIONS: These findings establish the liver microphysiologic system as a relevant model for the study of breast cancer metastases and entry into dormancy.

The actin released from profilin--actin complexes is insufficient to account for the increase in F-actin in chemoattractant-stimulated polymorphonuclear leukocytes.

Chemoattractant stimulation of polymorphonuclear leukocytes is associated with a nearly two-fold rise in actin filament content. We examined the role of the actin monomer sequestering protein, profilin, in the regulation of PMN actin filament assembly during chemoattractant stimulation using a Triton extraction method. Poly-L-proline-conjugated Sepharose beads were used to assess the relative concentration of actin bound to profilin with high enough affinity to withstand dilution (profilin-actin complex) and DNase I-conjugated beads to measure the relative concentration of actin in the Triton-soluble fraction not bound to profilin. Actin associated with the Triton-insoluble fraction (F-actin) was also measured. In unstimulated PMN, the relative concentration of actin bound to profilin was maximum. After FMLP stimulation, profilin released actin monomers within 10 s, with the profilin-actin complex concentration reaching a nadir by 40 s and remaining low as long as the cells were exposed to chemoattractant (up to 30 min). If FMLP was dissociated from PMN membrane receptors using t-BOC, actin reassociated with profilin within 20 s. Quantitative analysis of these reactions, however, revealed that profilin release of and rebinding to actin could account for only a small percentage of the total change in F-actin content. Determination of the total profilin and actin concentrations in PMN revealed that the molar ratio of profilin to actin was 1 to 5.2. When purified actin was polymerized in PMN Triton extract containing EGTA, removal of profilin from the extract minimally affected (12% reduction) the high apparent critical concentration at which actin began to assemble. Although profilin released actin at the appropriate time to stimulate actin assembly during exposure to chemoattractants, the concentration of profilin in PMN was insufficient to explain the high unpolymerized actin content in unstimulated PMN and the quantity of actin released from profilin too small to account for the large shifts from unpolymerized to polymerized actin associated with maximal chemoattractant stimulation.

Manganese oxide octahedral molecular sieves: preparation, characterization, and applications.

A thermally stable 3 x 3 octahedral molecular sieve corresponding to natural todorokite (OMS-1) has been synthesized by autoclaving layer-structure manganese oxides, which are prepared by reactions of MnO(4)(-) and Mn(2+) under markedly alkaline conditions. The nature and thermal stability of products depend strongly on preparation parameters, such as the MnO(4)(-)/Mn(2+) ratio, pH, aging, and autoclave conditions. The purest and the most thermally stable todorokite is obtained at a ratio of 0.30 to 0.40. Autoclave treatments at about 150 degrees to 180 degrees C for more than 2 days yield OMS-1, which is as thermally stable (500 degrees C) as natural todorokite minerals. Adsorption data give a tunnel size of 6.9 angstroms and an increase of cyclohexane or carbon tetrachloride uptake with dehydration temperature up to 500 degrees C. At 600 degrees C, the tunnel structure collapses. Both Lewis and Brönsted acid sites have been observed in OMS-1. Particular applications of these materials include adsorption, electrochemical sensors, and oxidation catalysis.

Efficacy, toxicity, pharmacokinetics, and in vitro metabolism of the enantiomers of ifosfamide in mice.

The enantiomers of the anticancer drug ifosfamide, (+)-(R)-IFF and (-)-(S)-IFF, were prepared from the racemic compound rac-IFF using enantioselective liquid chromatographic techniques. The efficacy, toxicity, and pharmacokinetics of the individual enantiomers and rac-IFF were studied in mice. The results of the studies indicate that there were no statistically significant differences between the efficacy of (+)-(R)-IFF, (-)-(S)-IFF, and rac-IFF against childhood rhabdomyosarcoma (HxRh28) maintained in vivo as a xenograft in immune-deprived female CBA/CaJ mice. Similar results were found in toxicity and pharmacokinetic studies conducted in non-tumor-bearing female CBA/CaJ mice. The production of two major metabolites, aldoifosfamide and isophosphoramide mustard, by mice hepatic microsomes from non-tumor-bearing female CBA/CaJ mice was also investigated. There were no statistically significant differences in the calculated kinetic parameters, Vmax and Km, of the production of these two metabolites when the separate enantiomers or the racemic mixture were used as substrate.

A liver microphysiological system of tumor cell dormancy and inflammatory responsiveness is affected by scaffold properties.

Distant metastasis is the major cause of breast cancer-related mortality, commonly emerging clinically after 5 or more years of seeming 'cure' of the primary tumor, indicating a quiescent dormancy. The lack of relevant accessible model systems for metastasis that recreate this latent stage has hindered our understanding of the molecular basis and the development of therapies against these lethal outgrowths. We previously reported on the development of an all-human 3D ex vivo hepatic microphysiological system that reproduces several features of liver physiology and enables spontaneous dormancy in a subpopulation of breast cancer cells. However, we observed that the dormant cells were localized primarily within the 3D tissue, while the proliferative cells were in contact with the polystyrene scaffold. As matrix stiffness is known to drive inflammatory and malignant behaviors, we explored the occurrence of spontaneous tumor dormancy and inflammatory phenotype. The microphysiological system was retrofitted with PEGDa-SynKRGD hydrogel scaffolding, which is softer and differs in the interface with the tissue. The microphysiological system incorporated donor-matched primary human hepatocytes and non-parenchymal cells (NPCs), with MDA-MB-231 breast cancer cells. Hepatic tissue in hydrogel scaffolds secreted lower levels of pro-inflammatory analytes, and was more responsive to inflammatory stimuli. The proportion of tumor cells entering dormancy was markedly increased in the hydrogel-supported tissue compared to polystyrene. Interestingly, an unexpected differential response of dormant cells to varying chemotherapeutic doses was identified, which if reflective of patient pathophysiology, has important implications for patient dosing regimens. These findings highlight the metastatic microphysiological system fitted with hydrogel scaffolds as a critical tool in the assessment and development of therapeutic strategies to target dormant metastatic breast cancer.

Multiple-dose pharmacokinetics of telmisartan and of hydrochlorothiazide following concurrent administration in healthy subjects.

This open-label, crossover study had two objectives: to compare the steady-state pharmacokinetics of high-dose telmisartan with and without coadministered high-dose hydrochlorothiazide and to compare the steady-state pharmacokinetics of hydrochlorothiazide with and without coadministered telmisartan. A total of 13 healthy males and females of nonchildbearing potential received the following oral, once-daily medications, each for 7 days: telmisartan 160 mg, hydrochlorothiazide 25 mg, and telmisartan 160 mg plus hydrochlorothiazide 25 mg. Between medication periods, there was a 14-day washout. Blood was collected at intervals over 48 and 84 hours, respectively, at the end of the 7-day dosing period for the determination of plasma telmisartan and hydrochlorothiazide concentrations by high-performance liquid chromatography. Predose blood samples were also collected on days 1, 6, and 7. Tolerability of single-agent and combination medication was monitored. For hydrochlorothiazide and telmisartan, given alone or in combination, there were no appreciable differences in trough plasma concentrations between days 6, 7, and 8; thus, at day 7, both agents had achieved steady state. Mean values of the primary end points (Cmax and AUC0-24) and secondary end points (Cmin and t1/2) for both telmisartan and hyrochlorothiazide were unaffected when administered simultaneously. Moreover, concurrent telmisartan had no effect on urinary excretion of hydrochlorothiazide. Transient lightheadedness, associated with postural hypotension, was the most common adverse event. The absence of any significant effects on the pharmacokinetics of either hydrochlorothiazide or telmisartan shows that no dose adjustment is required if the two agents are given concurrently for the management of hypertension.

The acoustical behavior of Acheta domesticus L. (Orthoptera: Gryllidae) following sublethal doses of parathion, Dieldrin and Sevin.

Studies were conducted on the effects of sublethal doses of an organophosphate, Parathion, a chlorinated hydrocarbon, Dieldrin, and a carbamate, Sevin, on the acoustical and sexual behavior of Acheta domesticus L. The LD10 of orally administered Parathion was 0.100 µg/g, that of Dieldrin was 0.066 µg/g, and that of Sevin was 0.330 µg/g. Parathion treated crickets were unable to emit pure calling, threat, or courtship songs. As a result of these changes in acoustic behavior, treated male crickets were unable to complete copulation.Oral administration of both Dieldrin and Sevin resulted in complete cessation of singing in all specimens for 3 to 6 hours. Once singing resumed there was a significant increase in chirp rate and pulse rate of the calling song.It is suggested that sublethal doses of Parathion act primaily on the peripheral neuromuscular system and the thoracic ganglia, whereas both Dieldrin and Sevin appear to act upon components of the brain, first in an inhibitory capacity and subsequently as excitants.

Fatal Plesiomonas shigelloides septicaemia in a splenectomised patient.

A case of fatal Plesiomonas shigelloides septicaemia is reported in a splenectomised patient. One week prior to his illness the patient was exposed to river water that was potentially contaminated with plesiomonads. Autopsy findings indicated that the plesiomonad may have invaded the blood stream through the terminal ileum.

The equine hypophysis: a gland for all seasons.

The intrahypophysial mechanisms involved in the control of gonadotrophin secretion remain unclear. In the horse, a divergent pattern of gonadotrophins is observed at different stages of the reproductive cycle in response to a single secretagogue (gonadotrophin-releasing hormone), and dramatic changes in fertility take place throughout the year in response to photoperiod. This species thus provides a useful model to investigate the regulation of fertility directly at the level of the hypophysis. A series of studies were undertaken to examine the cytological arrangements and heterogeneity of gonadotrophin storage in the pars distalis (PD) and pars tuberalis (PT) of the hypophysis of male and female horses. Specifically, the seasonal and gonadal effects on distribution, density and hormonal identity of gonadotrophs, the existence of gonadotroph-lactotroph associations and the expression of prolactin receptors (PRL-R) as possible morphological bases for the differential control of gonadotrophin secretion were investigated. It became apparent that both isolated and clustered gonadotrophs are normally distributed around the pars intermedia and surrounding capillaries in the PD, and in the caudal ventral region of the PT. In the PD, no effects of season or of reproductive state on the density or number of gonadotrophs could be detected in either male or female animals. In contrast, a fivefold increase in gonadotroph density was observed in the PT during the sexually active stage. In males, robust gonadal effects were detected on the gonadotroph population; orchidectomy significantly reduced both the number and proportion of gonadotrophs, in relation to other hypophysial cell types, in both the PD and PT regions. Luteinizing hormone (LH) monohormonal, follicle-stimulating hormone (FSH) monohormonal and bihormonal gonadotrophs were identified in the PD and PT of male and female horses. Interestingly, in males, the relative proportions of gonadotroph subtypes and the LH/FSH monohormonal gonadotroph ratio were not affected by either season or the presence of the gonads. In contrast, a larger proportion of monohormonal gonadotrophs was clearly observed in sexually active females. Specific gonadotroph-lactotroph associations and expression of PRL-R in cells other than gonadotrophs were detected in the PD throughout the annual reproductive cycle. In addition to a stimulatory gonadal effect on lactotroph density, a substantial gonadal-independent effect of season was apparent on this variable. The findings have revealed important seasonal and gonadal effects on the cytological configuration of the equine hypophysis, which may provide the morphological basis for the intrahypophysial control of fertility.

Famciclovir update. Chronic hepatitis B.

The growing body of preclinical data, as well as clinical data from the phase II doseranging study in immunocompetent patients and from liver transplant recipients participating in the compassionate use program, indicates that famciclovir offers the promise of safe and convenient oral treatment of chronic hepatitis B infection. The results of phase III pivotal studies are eagerly awaited. Denavir is a trademark of SmithKline Beecham plc.

Primary leiomyosarcoma of bone.

Adequate treatment of primary leiomyosarcoma of bone requires surgical ablation with the goals being those for any malignant tumor of bone--eradication of the lesion and preservation of as much function as possible. Careful preoperative staging will determine whether amputation is necessary or whether successful limb-saving resection is possible.

Health resource utilization associated with switching to risperidone long-acting injection.

OBJECTIVE: Studies have shown oral risperidone and conventional depot antipsychotics decrease direct healthcare costs largely by reducing hospitalization. Our aim was to assess the effect on bed stay of risperidone injection prescribed in normal clinical practice. METHOD: Patients prescribed risperidone long-acting injection (RLAI) were identified and followed-up for 1 year. Resource use data were collected for 3 years before and for 1 year after the initiation of RLAI. The main outcome measure was bed stay before and after the prescription of RLAI. RESULTS: Outcome data were available for 250 subjects. Eighty-one subjects (32.4%) completed 1 year's treatment. Days spent in hospital increased from (mean number/patient) 31 in year -3 to 44 in year -2 to 90 in year -1 to 141 in year +1. Direct healthcare costs increased accordingly. Outcome for RLAI continuers was similar to that of discontinuers. CONCLUSION: Switching to RLAI was associated with a continuation of the trend for increased bed stay and use of healthcare resources.

Social work roles in collaborative research.

Social workers in health care settings may be most effective in the development and implementation of collaborative research studies which jointly involve academic and health service institutions. This article describes: organizational issues significant to the integration of research into a health service system; interpersonal issues that effect the perspectives of research and service professionals in the daily operation of the research project; and social work skills for collaborative research studies. An on-going 5-year collaborative research study of approximately 7,000 participants will be used as a case example.

PIP: This article presents principles of collaborative multi-organizational research for use by social workers. To illustrate the organizational and interpersonal issues related to implementation of a joint research-service project, an ongoing study of the epidemiology of genital herpes is used as a case study. This project seeks to follow approximately 7000 women, drawn from Pennsylvania family planning clinics, for a 3-year period to determine the incidence and natural history of genital herpes. In the planning phase, the social worker was central in discussing the study design, methods of patient recruitment, and overall study purposes with the family planning clinic staff and in identifying potential problem areas (e.g., professional boundaries regarding patient contact, sharing of medical records). Another component of the preimplementation phase of a collaborative research-service project is the in-service education of clinical staff. It is important that research protocols interface as much as possible with existing clinic protocols. The social worker can play a liaison role in terms of developing tolerance for change and flexibility. Among the benefits to social workers of participation in such collaborative research projects are improved consultation skills, increased knowledge of research design and methodology, an opportunity to act as an advocate, and an opportunity to foster greater institutional research-service cooperation. Further collaboration between schools of social work and health care settings such as hospitals, primary health care programs, and community-based services is recommended.

Family planning utilization by black and white women: public health social work implications.

Black infant mortality is one of the most serious and long-standing public health problems in the United States. This article reports the findings of a study of the family planning records of 1143 residents of a city with one of the highest black infant mortality rates. The importance of increased social work involvement in the federally funded family planning system and specific social work strategies are discussed as methods to reduce black infant mortality.

Psychosocial influences on research subject recruitment, enrollment and retention.

Psychosocial factors may profoundly affect the successful implementation of a research study. The purpose of this paper is to describe psychosocial influences on the researcher-participant interaction during: (1) recruitment, (2) enrollment, and (3) retention and to provide guidelines for effective implementation of a study within a clinical health care setting. An interdisciplinary teamwork approach was used to identify and to resolve psychosocial issues. A study of 4781 family planning patients will be used as the case example.

PIP: Between 1984 and 1986, staff from 5 family planning clinics in western Pennsylvania enrolled 4781 women in a study of genital herpes. Clinic staff conducted follow-up contacts with them biannually and examined them yearly for 3 years. A social worker served as a consultant and liaison in the context of being a trouble-shooter. A nurse-researcher headed up onsite data collection and supervised nurses who visited clinic sites often during the week. They identified psychosocial issues as they arose. The principal investigator made all final decisions on interventions. The interdisciplinary team developed guidelines for researchers in recruitment, enrollment, and retention of study subjects. Some recruitment guidelines included developing positive relationships with staff who are the referring personnel to the study, conducting interview training before recruitment begins, and providing a private place to recruit study subjects. Some enrollment guidelines were to be physically present at routine intervals at the referring site,, be willing to make acceptable changes in research protocol to accommodate referring site, and inform subjects about the disease/condition being studies. Researchers need to stay in contact with subjects by either face-to-face meetings, phone calls, or mail as well as at the clinic to promote high retention. They also need to encourage questions and concerns of subjects. Researchers should also refer them to appropriate resources when needed. Social workers should consider these guidelines when interested in research since they promote a favorable environment amid many implementation problems. Since social workers receive academic and professional training in individual and group dynamics, administration, and research design and methodology, they are suitable to foster cooperative agreements in an interdisciplinary team.

Antibiotic therapy for enterobacter meningitis: a retrospective review of 13 episodes and review of the literature.

Enterobacter meningitis is an uncommon form of meningitis whose treatment poses a therapeutic dilemma because of the development of resistance to the third-generation cephalosporins while the patient receives therapy. In recent years, we have been using trimethoprim-sulfamethoxazole (TMP-SMZ) as treatment for this infection. In this report, we reviewed 13 episodes of enterobacter meningitis that were treated with various antibiotic regimens and 33 episodes from the literature. We found that the development of resistance to beta-lactam agents may be much higher than that seen in bacteremias (approximately 30%), that the case-fatality rate is lower among our patients than among those described previously, and that all patients who received TMP-SMZ were cured, compared with about 70% of those receiving beta-lactam agents. TMP-SMZ appears to be an acceptable alternative to the cephalosporins for the treatment of enterobacter meningitis.