Stable structures and superconducting properties of Ca-La-H compounds under pressure

The calcium hydrides and lanthanum hydrides under high pressures have been reported to have good superconducting properties with high-T_C. In this work, the structures and superconductivities of Ca-La-H ternary hydrides have been studied by genetic algorithm and density functional theory calculations. Our results show that at the pressure range of 100-300 GPa, the most stable structure of CaLaH₁₂has aCmmmsymmetry, in which there is a H₂₄hydrogen cage. It can be expected to have high possibility to be synthesized due to its large stability. Furthermore, the predictedT_Cof theCmmm-CaLaH₁₂structure is about 140 K at 150 GPa, and when the pressure decreases to 30 GPa, the CaLaH₁₂structure with aC2/msymmetry has a predictedT_Cof about 49 K. The CaLaH₁₂is suggested to be a stable good superconductor with large stability and performs well at relatively low pressures.

Study on superconducting Li-Se-H hydrides

The structures, stabilities and superconducting properties of LiSeH_n (n = 4-10) hydrides at 150-300 GPa were studied by the genetic algorithm (GA) and DFT calculation method. Three stable stoichiometries of LiSeH₄, LiSeH₆ and LiSeH₁₀ were uncovered under high pressure. Four other metastable stoichiometries of LiSeH₅, LiSeH₇, LiSeH₈, and LiSeH₉ were also studied. By analyzing the electronic band structure and electronic density of states, C2 LiSeH₄, Pmm2 LiSeH₆ and C2 LiSeH₁₀ were all found to be metal phases above 150 GPa. Electron-phonon coupling calculations showed that C2 LiSeH₄ and Pmm2 LiSeH₆ were promising superconductors. The predicted T_c values of C2 LiSeH₄ and Pmm2 LiSeH₆ were 77 K at 200 GPa and 111 K at 250 GPa, respectively.

All-Optical Volumetric Physiology for Connectomics in Dense Neuronal Structures

All-optical physiology (AOP) manipulates and reports neuronal activities with light, allowing for interrogation of neuronal functional connections with high spatiotemporal resolution. However, contemporary high-speed AOP platforms are limited to single-depth or discrete multi-plane recordings that are not suitable for studying functional connections among densely packed small neurons, such as neurons in Drosophila brains. Here, we constructed a 3D AOP platform by incorporating single-photon point stimulation and two-photon high-speed volumetric recordings with a tunable acoustic gradient-index (TAG) lens. We demonstrated the platform effectiveness by studying the anterior visual pathway (AVP) of Drosophila. We achieved functional observation of spatiotemporal coding and the strengths of calcium-sensitive connections between anterior optic tubercle (AOTU) sub-compartments and >70 tightly assembled 2-μm bulb (BU) microglomeruli in 3D coordinates with a single trial. Our work aids the establishment of in vivo 3D functional connectomes in neuron-dense brain areas.

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All-optical volumetric physiology = precise stimulation + fast volumetric recording

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Precise single-photon point stimulation among genetically defined neurons

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3D two-photon imaging by an acoustic gradient-index lens for dense neural structures

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Observation of 3D functional connectivity in Drosophila anterior visual pathway

Synthesis and structure of a cobalt coordination polymer based on 2,8-di(pyridin-4-yl)dibenzothiophene and 4,4-dicarboxydiphenylsulfone

A new coordination polymer {[Co2(DPDBT)2(DCPS)2(H2O)](H2O)} n (1) [DPDBT = 2,8-di(pyridin-4-yl)dibenzothiophene, H2DCPS = 4,4′-dicarboxydiphenyl sulfone], was synthesized under solvothermal conditions. Complex 1 exhibits a 2D structure with two different kinds of binuclear cobalt cluster units. The UV/Vis spectra of 1 and of the ligands were investigated, indicating that complex 1 is a potential wide gap semiconductor material.

[Evaluation of the effects of hospital nurse retention programs in Taiwan]

The purpose of the study was to examine the effectiveness of current nursing retention programs in hospitals in Taiwan and the relationships between job satisfaction and intention to stay. A proportional multi-stratified random sampling technique was used to recruit nurses who were working in accredited district and regional hospitals in the years 1996 to 1998. Data were collected through a structured questionnaire from 471 nurses with 2 years of nursing experience, and analyzed by non-parametric and logistic regression. The results showed that a majority of the respondents positively recognized the importance of the DOH retention policy and were satisfied with its implementation. Nurses whose working hospital had a retention program had higher job satisfaction and intention to stay than those without a retention program. Based on the findings, nursing and hospital administrators could develop retrievable data gathered during an ongoing organizational retention policy and develop strategic planning for stabilizing their clinical nursing workforce.

Holistic outcome measurement for terminally ill cancer patients in medical centers in Taiwan

The purpose of this cross-sectional study was to examine holistic patient outcomes for terminally ill cancer patients, as well as to examine whether different care patterns affect patient outcomes differently. Holistic patient outcomes were measured by the patients' quality of life, satisfaction with care, and cost of care. A purposive sampling of 224 subjects including 123 patients and 101 nurses was drawn from four medical centers in Taiwan. Among these settings, various care patterns were adopted and categorized into 4 groups: hospice inpatients, hospice team consultation, home hospice care services, and a conventional acute care group. Results showed that hospice inpatients had a higher quality of life, a higher level of satisfaction with the care and a lower average inpatient cost, whereas conventional care tended to have the highest length of hospital stay. Home hospice care patients had better psychological well-being than those with other care patterns. In addition, nurses' work satisfaction with the inpatients care unit tended to be significantly higher than with the other groups. The study findings not only provide an instrument for evaluating the quality of care, but also contribute to identifying patterns of care that will influence the dying process, which can only be beneficial for patients. Given the wide variety of healthcare services available now, understanding and selecting the most effective care patterns to enhance patient outcomes is of utmost importance in Taiwan.

[The effectiveness of implementing an unit-based shared governance model]

The purpose of the nonequivalent control group study was to establish a regional unit-based shared governance model. Fifty-three subjects distributing to experimental (n = 29) and control (n = 24) groups-age, working years, and education were matched statistically-were selected by "purposeful sampling" of Index of Professional Nurse Governance pretest mean scores from six units at a nursing department. Based on Martin's "systematic" evaluation model for shared governance, the study collected: (1) manager's and staff's perception of existing governance using open-ended questions, (2) measure of organizational efficiency using the IPNG and the Index of Working Satisfaction, and (3) the research team's assessment of the unit's willingness to continue this model in the future. The reliability and validity of the questionnaires were established. Intervention of the model was approximately four months, including: preparatory and evaluating phase: data was collected; educative phase: empowering managers and staff were educated in the shared governance concepts; implementing phase: shared governance team was built up. Two-tailed t and chi 2 tests were used to detect differences between the two groups. Results showed, after establishing the unit-based model, (1) an increase in the nursing professional governance and work satisfaction among nurses; (2) an enhanced partnership between managers and nurses; (3) staff nurses perceived increased autonomy, authority, and more frequently expressed their opinions to managers; (4) managers perceived their staff to have more potential competence, then task pushed effectively. The findings suggest that managers and nurses need to refine their professional roles based on the organizational mission, as well as to expand nurses' representation and participation in current organization-wide committees by trust and full delegation from their managers.

Automatic recognition of the source of temporomandibular joint sounds

Sounds evoked in the temporomandibular joint (TMJ) during jaw movements may indicate pathology. They are in dental clinics usually recorded by auscultation and noted in protocols by verbal, subjective descriptions. Time-frequency analysis of electronically recorded TMJ sounds makes possible a more objective and sophisticated analysis. Such sounds were recorded from four subjects and grouped into two sets. One was used for training a classifier, while the other was used for testing its ability to relate a given sound to the subject from which it was recorded. Both scale and time-shift invariant representations, as well as only time-shift invariant representations of the Reduced Interference Distributions of the TMJ sounds were used for pattern recognition. The nearest neighbor, zero-subspace and nearest constrained linear combination classification methods were employed. It was observed that TMJ sound patterns could be very typical for a given person. This indicates that our classification approach can be developed into a useful diagnostic tool by obtaining training sets from patients where a definitive diagnosis of TMJ pathology has been obtained.

Bilateral sound propagation characteristics in electronic TMJ sound recording

Temporomandibular Joint (TMJ) sounds, clicking and crepitation, are important signs of possible TM disorder or dysfunction (TMD). The sound are usually recorded and observed by stethoscope auscultation or palpation. Sound from one TMJ may propagate through head tissues and be recorded on the contra lateral side misleading the examiner to classify both joints as non-silent. Errors in localization of sound source may lead to an erroneous diagnosis. Widmalm et al. (1997) suggested a mathematical model for estimation of the sound propagation characteristics through the head tissues. A modified model applying the auto-spectral density and cross-spectral density of the signal was used to estimate the bilateral sound propagation characteristics of temporomandibular joint sounds from two subjects. The result indicates that the head tissues act as a bandpass filter causing strong attenuation in some frequency areas with little attenuation in others. The phase response of the transfer function provides a good mean to estimate the latency in time between sounds.

An evaluative study of the effects of the implementation of UBSG on nurses' perceptions of professional governance

Health care reform has been a major economic and political challenge in Taiwan. Successful implementation of change in hospitals requires managers to learn new skills. Unit-based shared governance (UBSG) is one innovation used to restructure health care organizations to promote the performance of professionals and to achieve goals for organizations. This research, conducted in a 150-bed community hospital, was a quasi-experimental study designed to evaluate the effectiveness of implementing UBSG. This article describes and compares the degree of nurses' perceptions of professional governance between a UBSG group (n = 29) and a control group (n = 24). The findings of this study indicate that the majority of UBSG respondents scored at a high level of participation in decision-making and professional practice (p < .05). Nurses in the UBSG group shared more in professional governance activities (p < .05). It is suggested that decentralized UBSG within a division of nursing can empower nurses. The study provides an empirical basis for implementing UBSG.

A quasi-experimental study on a quality circle program in a Taiwanese hospital

OBJECTIVE

To explore the impact of quality circles on job satisfaction, absenteeism, and turnover among hospital nurses in Taiwan.

DESIGN

A quasi-experimental research design.

SETTING

In November 1995, a study was initiated to establish quality circles in a 500-bed community hospital in Taiwan. After the administrative process and a pilot study, three of the experimental units began implementing the quality circle program in January 1997. For the comparison group, three non-quality circle medical-surgical units were selected from another building.

STUDY PARTICIPANTS

All registered nurses on the three selected units who met the criteria of having worked full-time on those units for > or = 6 months were included in the study. There were 53 full-time registered nurses (49 female, four male) who met the criteria and 100% participated. There were no significant differences between the quality circle group and the non-quality circle group in terms of sex, age, and number of years of working experience, education or marital status.

INTERVENTIONS

After obtaining administrative approval and support, the pilot study began with 3-month quality circle courses and 3-month quality circle process training for the experimental group nurses. Each circle has been meeting for 1 hour each week to identify problems, barriers, and solutions for effective implementation since 1997.

MAIN OUTCOME MEASURES

(i) Demographic data questionnaire; (ii) Stamps and Piedmont's Index of Work Satisfaction; (iii) hospital records for absenteeism and turnover data.

RESULTS

The data reveal that nurses of the three quality circle units felt more satisfied (P < 0.01) than did nurses from the three non-participating units. In the non-participating group, 36% had considered leaving the units, compared to 10% of nurses from the quality circle group. The turnover rate was significantly higher for the non-participating group (40%) than for the quality circle group (13%).

CONCLUSION

This quality circle program in a Taiwanese hospital significantly improved satisfaction, reduced absenteeism, and lowered turnover of nurses. The findings support other studies reported in the literature.

Computerized classification of temporomandibular joint sounds

Sounds, such as clicking and/or crepitation, evoked in the temporomandibular (jaw) joint during function may indicate pathology. Analysis of the reduced interference time-frequency distribution of these sounds is of diagnostic value. However, visual evaluation is expensive and error prone, and there is, thus, a need for automated analysis. The aim of this study was to find the optimal signal representation and pattern recognition method for computerized classification of temporomandibular joint sounds. Concepts of time-shift invariance with and without scale invariance were employed and mutually compared. The automated analysis methods provided classification results that were similar to previous visual classification of the sounds. It was found that the classifier performance was significantly improved when scale invariance was omitted. This behavior occurred because scale invariance interfered with the frequency content of the signal. Therefore, scale invariance should not be pursued in the classification scheme employed in this study.

False localization of TMJ sounds to side is an important source of error in TMD diagnosis

The results of the study indicate that the head tissues act as a band pass filter that is far from flat. Instead there seems to be strong frequency variations in attenuation of transmitted sounds. The sounds are subject to phase shift and time delay, which can be used to decide from which TMJ the sound comes. Bilateral electronic recording with high sampling rate (>> 44 kHz) is needed to accurately and consistently identify the origin of a TMJ sound. Further studies on autopsy specimens and large subject groups are motivated.

[11 beta-Hydroxysteroid dehydrogenase]

There are two types of 11 beta-hydroxysteroid dehydrogenase (11 beta-HSD). 11 beta-HSD 1 is an oxoreductase interconverting biologically active cortisol and inactive cortisone. 11 beta-HSD 2 is an exclusive oxidase only converting cortisol to cortisone. It has been recognized that 11 beta-HSD 2 confers the specificity of mineralocorticoid receptor in the kidney and protects the fetus from high levels of maternal glucocorticoids in the placenta. Lack or malfunction of this enzyme could result in the development of apparent mineralocorticoid excess syndrome and intrauterine growth retardation of the fetus. 11 beta-HSD is possibly involved in a number of other physiological and pathological conditions such as stress, hypertension, diabetes mellitus and neurodegenerative disorders. The functions of 11 beta-HSD 1 are not very well understood.

Insulin-like growth factor-II (IGF-II) messenger ribonucleic acid is expressed in steroidogenic cells of the developing ovine adrenal gland: evidence of an autocrine/paracrine role for IGF-II

Insulin-like growth factors (IGFs) are potent mitogenic and differentiation-promoting factors that regulate the growth and development of many fetal tissues. Their role in the development of the adrenal gland and activation of its function is not known. The latter is crucial in providing the stimulus for the maturation of various fetal organs and determines the onset of parturition in sheep. To examine the hypothesis that IGFs are important autocrine/paracrine regulators of fetal adrenal development in vivo, we localized IGF-I and IGF-II mRNAs and peptides in the adrenal glands of developing sheep fetuses and correlated the cellular distribution with localization of 3 beta-hydroxysteroid dehydrogenase, tyrosine hydroxylase, and phenylethanolamine-N-methyltransferase enzymes by immunohistochemistry. Adrenal glands from 60- to 75-day-old (n = 4), 100- to 110-day-old (n = 4), 120- to 130-day-old (n = 4), and 145- to 147-day-old (term; n = 4) fetal sheep and 1- to 4-day-old newborn lambs (n = 4) were dissected and either snap-frozen or fixed. Total RNAs were subjected to Northern analysis using ovine IGF-I and IGF-II cDNA probes. Seven IGF-II transcripts of 1.2-6.0 kilobases (kb) were identified in the adrenal glands of fetuses at all gestational ages, and in the newborn. By densitometry, the abundance of IGF-II mRNA was highest in the fetal adrenal gland at 60 days, decreased slightly between 60 and 100 days, remained relatively constant until term, and decreased significantly after birth. At all gestational ages, IGF-II mRNA was detectable in significantly greater abundance than IGF-I mRNA. IGF-I and IGF-II mRNAs were localized by in situ hybridization using 35S-labeled anti-sense cRNA probes, and the peptides by immunohistochemistry using specific antisera. Low levels of IGF-I mRNA were detected in the zona fasciculata, but not in the zona glomerulosa. There was strong hybridization of the IGF-II cRNA to the zona glomerulosa and fasciculata and to the capsule. The hybridization signal was greater in the zona fasciculata than in the zona glomerulosa. IGF-II mRNA was also detected in groups of cells within the medulla. Localization of IGF-II mRNA by in situ hybridization correlated well with the distribution of IGF-II immunoreactivity and with 3 beta-hydroxysteroid dehydrogenase-positive cells in the cortex and in groups of cells within the medulla.(ABSTRACT TRUNCATED AT 400 WORDS)

Opioid receptors are present in the hypothalamus but not detectable in the anterior pituitary of the developing ovine fetus

Exogenous opioids stimulate adrenocorticotropic hormone (ACTH) release in fetal sheep after day 125 of pregnancy (term 145 days), but not at day 110. To determine if the different response is due to an alteration in opioid-binding sites and to examine sites of opioid action on ACTH release, we established an in vitro binding assay to study changes and characteristics of opioid receptor binding sites in ovine fetal hypothalamus and pituitary during development. [3H]-naloxone was used as the radiolabelled ligand. The binding of [3H]-naloxone to hypothalamic membrane preparations was specific, saturable with respect to [3H]-naloxone concentration, and linear with the hypothalamic membrane protein content. Binding assays were conducted on tissues collected from fetuses at three gestational ages: days 110-115 and 125-130 and term. In all cases, Scatchard analysis revealed a single class of binding sites with high binding affinity (0.9-1.2 nM) which did not differ significantly with gestational ages. The binding capacity increased significantly from 45.4 +/- 2.5 fmol/mg protein at days 110-115 to 76.8 +/- 2.3 fmol/mg at days 125-130, but did not change further in term fetuses. When anterior pituitaries from the three groups of fetuses were processed and analyzed in a similar manner, no detectable binding was found. These results indicate (1) that endogenous opioid peptides may act at the hypothalamus rather than pituitary to regulate hypothalamic-pituitary-adrenal activity in the ovine fetus, and (2) the developmental changes in the binding capacity may contribute, in part, to the altered ACTH response reported in previous in vivo studies.

Intrinsic drug resistance in a human medullary thyroid carcinoma cell line: association with overexpression of mdrl gene and low proliferation fraction

Medullary thyroid carcinoma (MTC) is a cancer that is relatively insensitive to clinical chemotherapy. Our previous studies have demonstrated that an established human MTC cell line, TT, seems to possess an intrinsic resistance phenotype when tested for its chemosensitivity to multiple antineoplastic agents. We now report our investigation on the potential mechanisms responsible for the chemoresistance of TT cells. Northern analysis showed an increased level of multidrug resistance gene (mdrl) mRNA in TT and in an inherently drug-resistant colon carcinoma cell line, LoVo, when compared with CEM, a drug-sensitive leukemic lymphoblastic cell line; the latter two cell lines were included here as a control. Verapamil (10 microM) partially reversed resistance to doxorubicin in TT and LoVo cells, but had no effect on doxorubicin cytotoxicity to CEM cells. Expression of glutathione-S-transferase-pi (GST pi) gene was undetectable in TT, whereas, under similar conditions, GST pi mRNA was detectable in LoVo. Growth kinetics studies revealed that doubling times of the 3 cell lines in exponential growth were 95, 37, and 24 h for TT, LoVo and CEM, respectively. Flow-cytometric analysis showed that the percentage of TT population is S phase was 49% and 33% of the LoVo and CEM cell populations, respectively, while the G1/G0 fraction of TT was about 63% and 61% higher than that of LoVo and CEM, respectively. Our data suggest that the intrinsic chemoresistance in TT cells may be attributed to the combined factors of overexpression of the mdrl gene, a slower growth rate and a smaller proliferation fraction, although other factors or mechanisms that are yet to be investigated may also act in concert to contribute to the resistance phenotype of TT.

Deletion mapping on the distal third region of chromosome 1p in multiple endocrine neoplasia type IIA

Multiple endocrine neoplasia type IIA (MEN IIA) syndrome is an autosomal-dominant endocrine disorder that consists of medullary thyroid carcinoma (MTC), pheochromocytoma, and parathyroid hyperplasia. The susceptibility gene to this disorder has been mapped to chromosome 10. However, molecular studies of tumor cells from patients with familial and sporadic MTC and/or pheochromocytoma have shown a high frequency (50%) of abnormalities on chromosome 1p. In the present study, we examined MTC or pheochromocytoma tumor specimens from eight patients (familial and nonfamilial cases) to investigate gene losses on chromosomes 1 and 10 as potential mechanisms for the tumors' development. The patients studies had homozygous genotypes in their leukocyte DNAs for the chromosome 10 marker used in this study, and the patients were, therefore, uninformative. However, the patients were informative for the chromosome 1 markers and five of the patients' tumor-cell DNAs (63%) had allelic deletions at one or multiple loci on chromosome 1p, and one tumor DNA had evidence of possible gene rearrangement; in all six cases, the abnormalities involved the distal third of chromosome 1p. Furthermore, we determined that the common break point for the 1p deletions was at 1p32. These results suggest that a tumor suppressor gene in this defined region is involved in the development/progression of MTC and pheochromocytoma by being either lost or inactivated.

C-myc, N-myc, N-ras, and c-erb-B: lack of amplification or rearrangement in human medullary thyroid carcinoma and a derivative cell line

We investigated the copy number and possible rearrangement of the four protooncogenes, c-myc, N-myc, N-ras, and c-erb-B, in DNA from seven untreated primary cancers or metastases of medullary thyroid carcinoma and an established human medullary thyroid carcinoma cell line, TT, using the Southern blotting technique. The purpose of this study was two-fold: 1) to examine whether protooncogene perturbations in medullary thyroid carcinoma could be considered as a prognostic marker; and 2) to determine whether the protooncogenes could have a possible role in medullary thyroid tumorigenesis. Neither amplification nor rearrangement of the protooncogenes was detectable in the DNA from any tumor samples or in the cell line. Our results suggest that DNA-evident amplification and rearrangement of the c-myc, N-myc, N-ras, and c-erb-B oncogenes may not be mechanisms through which these oncogenes become activated in this malignancy.

Quantification of opioid-binding sites in the ewe hypothalamus

Opioid-binding sites were quantified in the ewe hypothalamus using [3H]diprenorphine ([3H]DIP) as the radioligand. [3H]DIP binding to hypothalamic membrane preparations was stereospecific, saturable with respect to [3H]DIP concentration, and linear with hypothalamic membrane protein content. Scatchard analysis revealed a single class of binding sites. There were no significant differences in binding site concentration or binding affinity in hypothalami from intact ewes during the breeding and non-breeding seasons, or from long-term ovariectomized ewes with and without oestradiol treatment during the breeding season. Thus, whilst ovarian steroid hormones are known to modify LH responses to opioids and their antagonists in the ewe in vivo, they do not appear to do this by modulating the numbers of hypothalamic opioid-binding sites.

Controls of corticotrophin-releasing factor output by hypothalamic tissue from fetal sheep in vitro

Corticotrophin-releasing factor (CRF) is thought to be an important physiological regulator of the pituitary-adrenal axis in fetal sheep and, as such, plays a fundamental role in the initiation of parturition in this species. However, little is known of the controls of CRF secretion from the fetal hypothalamus. We looked for the presence of CRF in fetal hypothalami, and examined whether the hypothalamic CRF concentration or molecular species changed in relation to gestational age. We established an in-vitro perifusion system to examine the release of CRF from perifused hypothalami taken from fetuses at day 100 and day 140 of pregnancy, under basal conditions and in response to potassium depolarization and/or dexamethasone administration. Immunoreactive CRF was present in fetal hypothalami as early as day 100 (2.42 +/- 0.99 (S.E.M.) micrograms/g protein, n = 9) and in similar concentrations at day 140 (2.31 +/- 0.69 micrograms/g protein, n = 9). There was a significant (P less than 0.05) increase in hypothalamic CRF content to 14.79 +/- 4.09 micrograms/g protein (n = 16) between day 122 and day 135 of gestation. Using Sephadex G-75 chromatography, hypothalamic extracts at day 100, days 122-135 and day 140 eluted with a single peak of immunoreactivity which corresponded to synthetic ovine CRF(1-41). The basal release of CRF from perifused hypothalami at day 140 (76.6 +/- 10.4 pg/fraction, n = 8) was significantly (P less than 0.05) greater than at day 100 (50.1 +/- 10.2 pg/fraction, n = 11). Dexamethasone significantly inhibited basal CRF release at day 140 of gestation but not at day 100.(ABSTRACT TRUNCATED AT 250 WORDS)

Failure of melatonin to influence endogenous opioid effects on LH secretion in the anoestrous ewe

In May mature seasonally anoestrous ewes were implanted with melatonin which advanced the onset of cycles by about 1 month. The LH response to an opioid antagonist, WIN-3, was determined 5, 15, 25 and 60 days after melatonin implantation, by intravenous administration of WIN-3 (12.5 mg/dose) 4 times at 15-min intervals during both the 1st and the 5th hour of an 8-h treatment period. There was no effect of WIN-3 at 5, 15 and 25 days after melatonin implantation. At 60 days LH concentration and pulse frequency were significantly increased (P less than 0.05 and less than 0.01 respectively) in response to WIN-3 treatment, but only in those animals which had begun reproductive cycles, an effect known to be mediated by the presence of progesterone. We were therefore unable to find evidence to support the hypothesis that the influence of melatonin in advancing the breeding season may be via an opioidergic pathway.

Lethal efficacy of doxorubicin on human medullary thyroid carcinoma cells in vitro

Cytotoxicity of doxorubicin was evaluated on a cultured human thyroid carcinoma (MTC) cell line, TT, by the colony-formation technique. The concentration-dependent survival curve showed a biphasic exponential pattern. Doxorubicin in concentrations of 5 X 10(-9) to 3 X 10 (-5) M produced a 15% to 71% cell kill after 1 hr of treatment. Mean lethal concentrations, 0.6 and 59 micrograms/ml, were considerably higher than those reported for cells of other tumors. Prolonged continuous treatment with a single concentration (1 X 10(-8) M) resulted in a cell kill of only 39% by 20 hr, and no further improvement was achieved with extended treatment of up to 48 hr. That doxorubicin activity was not enhanced by prolonged treatment was shown by controls not to be due to inactivation of the drug. Our results suggest that TT cells are somewhat resistant to doxorubicin and that acute administration of larger doses rather than continuous infusion of small doses should perhaps be considered when doxorubicin is used in patients with metastatic MTC.

Enhancement of hormonal synchronization and 5-fluorouracil cytotoxicity in breast cancer cells by low concentration of thymidine

A method is described that applies a low concentration of thymidine to achieve maximal hormonal synchronization in cultures of an established human breast cancer cell line, MCF-7. The method consists of sequential treatments with tamoxifen, estradiol, and thymidine. The increase (3.8 fold) in the S-phase fraction achieved by this method is higher than that (2.6 fold) achieved by a solely published method using tamoxifen block plus estradiol rescue. The MCF-7 cells, which have an enhanced labeling index (S-phase fraction) after being treated with the synchronizing method, have a markedly increased sensitivity to an S-phase-specific cytotoxic agent, 5-fluorouracil. This method may have potentially important implications for clinical chemotherapeutic strategy in the treatment of breast cancer.

Reduction of estrogen receptor concentration in MCF-7 human breast carcinoma cells following exposure to chemotherapeutic drugs

To study the effects of commonly used chemotherapeutic drugs on estrogen receptor (ER) of human breast cancer, we investigated the specific binding of [3H]estradiol within intact MCF-7 human breast cancer cells after 1 to 4 hr of exposure to methotrexate (0.5 to 50 micrograms/ml), 5-fluorouracil, and vincristine in serum- and hormone-free medium. Intracellular [3H]estradiol binding was either slightly increased (methotrexate and 5-fluorouracil) or not changed (vincristine) during the first 2 hr of drug exposures at 37 degrees, but slightly decreased at the third hr. After 4 hr of drug treatments, [3H]estradiol binding within MCF-7 cells was reduced by 30 to 70%; the response was dose dependent. Most (80 to 83%) of the intracellularly bound [3H]estradiol was found within the nuclei, and the drug-induced reduction of ER was reflected by a depleted nuclear uptake of [3H]estradiol. The Scatchard plot showed a large decrease of receptor number per cell with no apparent alteration in the binding affinity. The reduction of ER was reversible; regeneration of receptors to the control level occurred at either 4 hr (methotrexate and 5-fluorouracil) or 8 hr (vincristine) after removal of these drugs. The restoration was followed by an increase of ER beyond the control level. The dose-dependent depletion of ER by these cytotoxic drugs was also detectable in a second ER-positive cell line, MDA-MB-134. These data indicate that the cytotoxic drugs may cause a dose-dependent, reversible depletion of ER in human breast cancer, and the effect seems to be due to inhibition of receptor synthesis rather than inhibition of the binding of estradiol to its receptors.

Estrogen receptor: a prognostic factor in breast cancer

Two-hundred-seventeen women with primary breast carcinoma had an estrogen receptor determination tested by both the dextran-coated charcoal assay and sucrose density gradient. The results were correlated with the disease-free interval, survival, response to hormone therapy or chemotherapy, and site of recurrent disease. The disease-free interval (DFI) was significantly longer in premenopausal patients with estrogen receptor positive (ER+) determination compared with premenopausal patients with estrogen receptor negative (ER-) determinations, irrespective of nodal involvement (P less than 0.05). There was no difference between the postmenopausal patients. The survival of the ER+ patients was statistically longer than that of the ER- patients (P less than 0.05). Statistical significance remained when the patients were grouped according to menopausal status or nodal involvement (P less than 0.002 or less). Sixty-two patients were treated with hormonal therapy, either ablative or additive. Forty-eight percent of patients with ER+ responded compared with 6% of patients with ER- (P less than 0.0005). Seventy-nine patients received chemotherapy; 52% of the ER+ and 57% of the ER- patients responded (P less than 0.5). ER+ tumors had a predilection to metastasize in skin and bone, while ER- tumors metastasized more commonly to the viscera and brain.

Hypercalcemia in patients with known malignent disease

In 82 patients, a preoperative diagnosis of primary hyperparathyroidism has been established by means of transfemoral neck vein catheterization and measurement of serum immunoreactive parathyroid hormone (iPTH). Twenty-five of these patients have had cancer in other parts of the body but with no evidence of recurrence or metastasis. One patient had carcinoma of the colon with metastases, and four were members of families with multiple endocrine adenomatosis (MEA, Types I and II). In six other hypercalcemic patients, high levels of iPTH were found also in the effluent blood from cancer sites other than the parathyroid gland, secondary to ectopic hormone production or pseudohyperparathyroidism. In addition, a high serum level of iPTH was found in the superior vena cava of a seventh patient who had carcinoma of the breast but no clinical or radiological signs of recurrence or metastasis with the exception of an enlarged liver. This iPTH finding was interpreted as being, probably, the result of parathyroid adenoma in either the neck or the mediastinum. At the time of operation, a transcervical mediastinal search was made. Four normal cervical parathyroid glands were found; three were removed. Hypercalcemia persisted after operation, and the patient died. At postmortem examination, microscopic study revealed that the disease had metastasized to lungs and hilar lymph nodes. There was massive metastasis in the liver; the liver contained a large amount of iPTH. The results of these investigations suggest that (1) venous catheterization of the neck veins and the effluent blood from extraparathyroid tumors aid in identifying and localizing iPTH production; (2) primary benign hyperparathyroidism is not uncommon in patients with cancer, and its co-existence must be recognized; (3) high serum iPTH level in the superior vena cava may be found in patients with metastatic or primary cancer of the thoracic cavity; and (4) hyperparathyroidism may be the first hint of a familial multiple endocrine syndrome.

Characterization of an inhibitor for luteinizing hormone receptor site binding

An inhibitor for luteinizing hormone (LH) receptor site binding has been partially purified from aqueous extracts of ovaries from pseudo-pregnant or pregnant rats. The LH receptor binding inhibitor (LH-RBI) was heat-resistant, partially inactivated by trypsin or pronase digestion, and had a molecular weight of approximately 3800 daltons. The LH-RBI was not found in the ovary of mature non-pregnant rats or immature rats, nor was it found in testis or liver extracts. The LH-RBI strongly inhibited the in vitro binding of 125I-labeled ovine LH to ovarian LH receptors but did not inhibit 125I-labeled ovine prolactin binding to ovarian PRL receptors.