Search PubMed⌕ Search

Biomedical subjects

W J Hrushesky

Publications and source records attributed to W J Hrushesky.

At least 19 recordsLinked to original sources
PubMed2001

Tumor chronobiology.

Traditionally, drug delivery has meant getting a simple chemical absorbed predictably from the gut or from the site of injection. A second-generation drug delivery goal has been the perfection of continuous constant rate (zero-order) delivery of simple xenobiotic molecules or common hormones. Living organisms are not 'zero-order' in their requirement for or response to drugs. They are predictable resonating dynamic systems, which require different amounts of drug at predictably different times within the circadian cycle in order to maximize desired and minimize undesired drug effects.

Animals↗
PubMed2001

Circadian expression of clock genes in human oral mucosa and skin: association with specific cell-cycle phases.

We studied the relative RNA expression of clock genes throughout one 24-hour period in biopsies obtained from the oral mucosa and skin from eight healthy diurnally active male study participants. We found that the human clock genes hClock, hTim, hPer1, hCry1, and hBmal1 are expressed in oral mucosa and skin, with a circadian profile consistent with that found in the suprachiasmatic nuclei and the peripheral tissues of rodents. hPer1, hCry1, and hBmal1 have a rhythmic expression, peaking early in the morning, in late afternoon, and at night, respectively, whereas hClock and hTim are not rhythmic. This is the first human study to show a circadian profile of expression for all five clock genes as documented in rodents, suggesting their functional importance in man. In concurrent oral mucosa biopsies, thymidylate synthase enzyme activity, a marker for DNA synthesis, had a circadian variation with peak activity in early afternoon, coinciding with the timing of S phase in our previous study on cell-cycle timing in human oral mucosa. The major peak in hPer1 expression occurs at the same time of day as the peak in G(1) phase in oral mucosa, suggesting a possible link between the circadian clock and the mammalian cell cycle.

ARNTL Transcription Factors↗
PubMed2001

Cisplatin-incorporated polymeric micelles eliminate nephrotoxicity, while maintaining antitumor activity.

cis-Diamminedichloroplatinum (II) (cisplatin, CDDP), a potent anticancer agent, was bound to the aspartic acid residues of poly(ethylene glycol)-poly(aspartic acid) (PEG-P(ASP)) block copolymer by ligand substitution reaction at the platinum atom of CDDP. The polymeric drug thus obtained was observed to form a micelle structure in aqueous medium, showing excellent water solubility. In the present study, in vitro and in vivo antitumor activity against several human tumor cell lines, toxicity and pharmacokinetic characteristics in rodents of CDDP-incorporated polymeric micelles (CDDP / m) were evaluated in comparison with those of CDDP. In vitro, CDDP / m exhibited 10 - 17% of the cytotoxicity of CDDP against human tumor cell lines. CDDP / m given by intravenous (i.v.) injection yielded higher and more sustained serum levels than CDDP. In vivo CDDP / m treatment resulted in higher and more sustained levels in tumor tissue than CDDP, and showed similar antitumor activity to CDDP against MKN 45 human gastric cancer xenograft. CDDP / m treatment caused much less renal damage than CDDP. These results indicate that CDDP / m treatment can reduce CDDP-induced nephrotoxicity without compromising the anticancer cytotoxicity of CDDP.

Animals↗
PubMed2000

Circadian organization of thymidylate synthase activity in normal tissues: a possible basis for 5-fluorouracil chronotherapeutic advantage.

Fluoropyrimidines induce cytotoxicity, in part, by inhibiting the proliferation-coordinated enzyme thymidylate synthase (TS), which is essential for DNA synthesis. Tumor TS levels are clinically predictive of post-surgical tumor recurrence and of response to fluoropyrimidine chemotherapy. Fluoropyrimidine drug toxicity and efficacy each vary reproducibly in humans and animals, depending upon their circadian timing. In vivo, normal tissues and some tumor tissues exhibit circadian coordination of cellular proliferation. We therefore asked whether TS activity is coordinated rhythmically throughout the day in the normal proliferative tissues most damaged by fluoropyrimidine drugs. To assess tissue and time of day TS activity differences, we harvested normal tissues from female mice living on a 12:12 hr light:dark schedule at each of 6 different equispaced times throughout a 24 hr cycle and measured TS catalytic activity. We observed up to 10-fold differences in vivo in TS activity among different normal tissue types, roughly paralleling their proliferative state and relative fluoropyrimidine sensitivity. In normal tissues most damaged by fluoropyrimidines (bone marrow, small intestinal mucosa and oral mucosa/tongue), TS activity varies up to 2-fold throughout each day. In bone marrow, the circadian pattern of TS activity parallels the circadian rhythm in proliferation in this tissue. This circadian organization of TS, one of the primary fluoropyrimidine targets in normal tissues, probably contributes in vivo to the time of day differences in the toxic-therapeutic ratio of circadian-timed fluoropyrimidine drug therapy.

Animals↗
PubMed2000

The temporal organization of life: the impact of multi-frequency non-linear biologic time structure upon the host-cancer balance.

The current scientific paradigm, based upon an erroneous assumption of linear biologic reality and simple cause and effect relationships, has outlived its usefulness. In order to begin to turn the voluminous data the reductive process provides us with daily into meaningful understanding of life, it is essential to integrate these data within a complex, multi-frequency temporo-spatial framework. This rhythmic chronobiology more accurately depicts the life process, as well as its evolutionary and ongoing vital interaction with the pulsating cosmic resonance structure. Examples of the kinds of thinking and experiments necessary to exploit this new paradigm are provided.

Antineoplastic Agents↗
PubMed1999

Circadian coordination of cancer growth and metastatic spread.

To understand whether mammalian circadian time structure measurably affects the host-cancer balance, we studied tumor-take frequency after s.c. tumor cell inoculation and the number of pulmonary tumor nodules after i.v. tumor cell injections at each of 6 equispaced times of day. We employed 2 genetically distinct mouse strains and 2 different tumor model systems, a methylcholanthrene A-induced fibrosarcoma of C(3)HeJ mice and 2 B(16) melanoma cell lines of vastly different metastatic efficiency in C57 Black/6 mice. Fibrosarcoma cells were injected s.c. in 1 of 8 different doses, at 1 of 8 permutated anatomic sites and at 1 of 6 equispaced circadian times, in 96 female C(3)HeJ mice maintained under a synchronizing schedule of 12 hr light alternating with 12 hr dark. Regardless of tumor cell dose and inoculum location, tumor-take frequency depended strongly upon the circadian stage of tumor cell inoculation. Injections of between 2,000 and 50,000 live tumor cells inoculated near the daily sleep/wake interface resulted in the lowest incidence of tumor take compared with inoculation at other times of day. In the experimental i.v. B(16) melanoma metastatic model (N = 110), the capacity of both high and low metastatic potential clones to successfully metastasize to lung depended, to a large extent, upon when in the day each of these clones was injected. Similar to the fibrosarcoma data, the daily sleep/wake boundary was the time of day associated with the greatest resistance to metastatic spread.

Animals↗
PubMed1998

Menstrual timing of breast cancer surgery.

PURPOSE AND DESIGN: This is a critical review of the growing body of data, 32 retrospective studies of the outcomes of 9,665 women published since 1989, relevant to the possibility that the timing of primary breast cancer resection within the menstrual cycle impacts breast cancer recurrence and/or spread and patient survival. This article evaluates and contrasts the adequacy of information and data analysis presented in each publication. The overall purpose of this exercise is to rigorously determine the relative strength of the hypothesis that the menstrual cycle timing of operation impacts outcome and, thereby, to determine whether or not a specific change in the practice of breast surgical oncology can be recommended. RESULTS: The single most completely reported and thoroughly analyzed series, involving 1,175 young women, indicates that surgical resection timing is likely to be relevant to outcome. Seven additional high-quality studies involving 2,864 women have been most completely reported. While two of these eight find no impact, six (75%) of these studies find that breast cancer outcome is affected by operative timing. Nine of the remaining 24 less-complete studies report a statistically significant effect of operative timing. Among these 15 studies of the fates of more than 5,000 women, the opportune menstrual cycle phase almost invariably includes the putative luteal phase. A large number of retrospective studies of widely varying quality find no outcome difference as a function of resection timing. The adequacy of design of each of four ongoing prospective studies is found lacking. CONCLUSIONS: Although it is likely that the menstrual cycle phase of operation is relevant to outcome, the nature of the available data cannot allow a clear recommendation of precisely when to operate. It is, therefore, concluded that current retrospective data are inadequate to recommend an immediate change in practice. Prospective studies of this potentially important question are essential. The prospective trials initiated to date will not be able to definitively answer this question because of inadequate chronobiological design. The minimal requirements for adequate prospective study are delineated.

Animals↗
PubMed1998

Distinct circadian time structures characterize myeloid and erythroid progenitor and multipotential cell clonogenicity as well as marrow precursor proliferation dynamics.

Circadian differences in the susceptibility of the marrow to the effects of radiation, myelotoxic drugs, and growth factors suggest that hematopoietic processes vary significant throughout each day. One mechanism possibly responsible for the differing degrees of marrow damage sustained from a fixed dose of a cytotoxic agent at different times of day is the circadian organization of cell cycle events. Previous circadian rhythm-oriented studies of proliferation using unfractionated marrow have reported seemingly contradictory peak and nadir times of day. Marrow represents a heterogeneous population of stem cells and various hematopoietic progenitors whose proliferation and differentiation are controlled by both common and unique factors. Therefore, we examined lineage-specific circadian marrow proliferative dynamics for evidence of parasynchronous circadian DNA synthesis. Cell cycle phase was determined using flow cytometry with both propidium iodide staining and 5-bromo-2'-deoxyuridine (BrdU) incorporation concurrently with cell culture-based determinations of lineage-specific progenitor numbers in the same marrow samples. Although no clear circadian (24-hour) rhythm characterized unfractionated marrow DNA synthesis, both erythroid- and myeloid-enriched subpopulations demonstrated distinct circadian patterns with respect to the percentage of cells incorporating BrdU, with up to 50% differences throughout each day. Interestingly, these circadian rhythms in erythroid and myeloid progenitor cell DNA synthesis are entirely different from one another. The lineage-specific circadian patterns in the fraction of cells undergoing DNA synthesis are, in part, paralleled by up to eightfold larger circadian differences in erythroid and myeloid colony numbers. Multipotential colony numbers likewise vary throughout the day, with a unique pattern of their own. The predominant period length of daily rhythms in colony numbers and their amplitudes differ as a function of the stage of progenitor commitment. Multipotent and early progenitor colony numbers each exhibit 24-hour rhythms, with three- to fivefold daily peak-trough differences, whereas later progenitor colony numbers exhibit two peaks per day (12-hour rhythms) with twofold peak-trough differences throughout each day. In vivo erythropoietin (Epo) administration enhances daily rhythms in erythroid colony numbers by increasing their amplitudes while leaving their circadian shapes virtually unchanged. The increment in erythroid colony numbers after Epo administration varies up to 16-fold with the time of day of treatment. In summary, we have defined distinctly different lineage-dependent circadian patterns of marrow progenitor numbers and proliferating cells. We can infer from these data that the circadian timing of administration of physical, chemical, or biologic agents, whose bioactivity toward marrow precursors depends on the cell cycle phase of its presentation, can be expected to affect this activity predictably and significantly. These results may have practical applications in improving stem and progenitor cell yields by optimal circadian timing of growth factor administration and harvest.

Animals↗
PubMed1996

Irreversible inactivation of interleukin 2 in a pump-based delivery environment.

The physical stability of pharmaceutical proteins in delivery environments is a critical determinant of biological potency and treatment efficacy, and yet it is often taken for granted. We studied both the bioactivity and physical stability of interleukin 2 upon delivery via continuous infusion. We found that the biological activity of the delivered protein was dramatically reduced by approximately 90% after a 24-hr infusion program. Only a portion of these losses could be attributed to direct protein deposition on the delivery surfaces. Analysis of delivered protein by size exclusion chromatography gave no indication of insulin-like, surface-induced aggregation phenomena. Examination of the secondary and tertiary structure of both adsorbed and delivered protein via Fourier-transform infrared spectroscopy, circular dichroism, and fluorescence spectroscopy indicated that transient surface association of interleukin 2 with the catheter tubing resulted in profound, irreversible structural changes that were responsible for the majority of the biological activity losses.

Acrylamide↗
PubMed1996

Circadian rhythms and cancer chemotherapy.

Temporal coordination of biologic processes with an approximately 24-h cycle (circadian) is common throughout the animal and plant kingdom and even in some prokaryotic organisms. In all organisms studied, the capability to keep biologic time is an inherited characteristic located intracellularly. These biological clocks anticipate and get the organism ready for regular environmental changes. This indicates both the ubiquity and the weight of the selective environmental pressure to keep time accurately. Several molecular strategies for biologic time keeping have apparently arisen independently several times throughout evolution. The anatomic, biochemical, and molecular mechanisms of the clock are in the process of being defined. This temporal organization at the cellular, organ, and organismic levels results in predictable differences in the capacity of plants, animals, and human beings to respond to therapeutic interventions administered at different times throughout important biologic cycles (e.g., circadian timed therapy). In the treatment of the cancer bearing host, circadian timing of surgery, anticancer drugs, radiation therapy, and biologic agents can result in improved toxicity profiles, enhanced tumor control, and improved host survival. The routine clinical application of such principles is facilitated by the availability of programmable drug delivery devices. Rhythm frequency ranges other than 24-h (e.g., low frequency: menstrual; high frequency: 10 to 120 min) may also be important to understanding health and disease and to designing successful therapy in diseases as diverse as cancer, infertility, and diabetes.

Animals↗
PubMed1995

Steroid-responsive interstitial lung disease in patients receiving 2'-deoxy-5-fluorouridine-infusion chemotherapy. A report of three cases.

BACKGROUND: Continuous infusion of 2'-deoxy-5-fluorouridine (FUdR) has shown promise in its activity against metastatic renal cell carcinoma. Its side-effect profile is dominated by gastrointestinal toxicity; there are no known adverse pulmonary reactions. To the authors' knowledge, this is the first report on the development of lung toxicity in three patients receiving FUdR-infusion chemotherapy for metastatic renal cell carcinoma. METHODS: The hospital charts of three patients presenting with pulmonary symptoms during FUdR chemotherapy were reviewed. A literature search was performed regarding FUdR-related pulmonary toxicity. RESULTS: Nonproductive cough, dyspnea, and fever appeared within the 10th chemotherapy cycle. Chest radiographs showed interstitial disease in each case, accompanied by a restrictive pattern by pulmonary-function testing. Lung biopsies were performed on two patients showing a pattern of interstitial inflammation. Discontinuing FUdR and instituting steroidal therapy invariably improved symptoms, as was evident by chest radiographs and pulmonary function tests. In one patient, resuming FUdR treatment resulted in a recurrence of the respiratory symptoms, which was controlled with an increased steroidal dose. All three patients required low dose steroids to maintain their baseline respiratory functions. CONCLUSIONS: 2'-deoxy-5-fluorouridine-related lung toxicity is an uncommon event and occurs late in the treatment course. It is rapidly symptomatic and responds readily to steroidal therapy.

Aged↗
PubMed1995

Cisplatin-associated anemia: an erythropoietin deficiency syndrome.

Cisplatin-based therapy results in a cumulative anemia that is disproportionate to the effects on other blood cells. The severity of this treatment-induced anemia and the resultant transfusion requirement in cancer patients correlate with cisplatin-induced renal tubular dysfunction. Observed/expected serum erythropoietin (EPO) ratios decline with progressive cisplatin therapy and are proportionate to the degree of renal dysfunction. Recovery from anemia and of observed/expected serum EPO ratios in patients occurs after cessation of cisplatin therapy, along with restoration of renal tubular function. Creatinine clearance, however, remains permanently depressed. Cisplatin-treated rats develop progressive renal dysfunction and anemia that persists for many weeks, without effects on white blood cell counts. The anemia is also associated with a lack of expected EPO and reticulocyte response. With EPO administration, cisplatin-treated rats exhibit a greater reticulocyte response and hematocrit increment then non-cisplatin-treated rats given EPO, indicating minimal erythroid precursor cell damage from cisplatin. These results indicate the primary etiology of cisplatin-associated anemia is a transient, but persisting EPO deficiency state resulting from cisplatin-induced renal tubular damage, which can be prevented or treated by hormone (EPO) replacement.

Aged↗