Detection of melanoma cells in peripheral blood stem cell harvests of patients with progressive metastatic malignant melanoma

The detection of melanocyte-specific messenger RNA in patients with malignant melanoma suggests the potential contamination of peripheral blood stem cell (PBSC) harvests by neoplastic cells. In this study, the melanocyte-specific transcripts of tyrosinase and Melan-A/MART-1 were used to detect neoplastic cells in PBSC harvests of nine metastatic malignant melanoma patients. Only one patient's PBSC harvest tested positive for tyrosinase. All harvests were negative for Melan-A/MART-1. Our results suggest that contamination of PBSC harvests with neoplastic cells may not contribute to disease progression following high-dose chemotherapy in advanced malignant melanoma.

A role for the circadian clock of the suprachiasmatic nuclei in the interpretation of serial melatonin signals in the Syrian hamster

Seasonal rhythms of reproduction in the Syrian hamster are triggered by the pineal hormone melatonin. By varying the parameters of systemic infusions of exogenous melatonin delivered to pinealectomized hamsters, it has been shown that the hypothalamus is sensitive to the duration of individual signals, which serve as an inverse coding of day length. It also has been shown that animals are sensitive to the temporal structure of a series of signals insofar as a series of melatonin infusions of appropriate number and duration may fail to invoke a gonadal response if they are presented at inappropriate frequencies. Although the endogenous circadian pacemaker of the suprachiasmatic nucleus (SCN) is not thought to be involved in the measurement of or response to melatonin signal duration, its contribution to the interpretation of a series of melatonin signals remains to be determined. Syrian hamsters are able to show a short-day-like gonadal response to a series of melatonin signals delivered on a variety of noncircadian schedules, including one in which a "random" pattern of infusions is employed. This study investigated the role of the SCN in the interpretation of such infusion paradigms. Adult male Syrian hamsters received electrolytic lesions of the SCN. Pinealectomized, lesioned, and intact hamsters then were infused with melatonin or saline at one of three different phases of the day in a random pattern such that no signal was predictive of the timing of the next. Other lesioned and intact animals received melatonin or saline at the same time daily. After 6 weeks, control saline-infused animals in both lesioned and intact groups had large testes. However, sham animals receiving melatonin in the random infusion pattern had regressed testes, as did the lesioned animals receiving melatonin at the same phase every day. By contrast, lesioned animals that received melatonin in the random pattern of infusion did not show a short-day gonadal response. These results suggest that although the SCN is not necessary for measurement of the duration of individual signals, it may play a role in the interpretation of a series of melatonin signals in which the number of melatonin signals and the period of time over which they are encountered need to be compared.

Peripheral blood tyrosinase messenger RNA detection and survival in malignant melanoma

BACKGROUND

The most widely accepted criteria for the evaluation of prognosis of malignant melanoma are histopathologic and clinical presentation. No currently available laboratory tests provide additional prognostic information. It has recently been suggested that reverse transcription and polymerase chain reaction (RT-PCR)-based detection of tyrosinase messenger RNA (mRNA) in peripheral blood might be useful in the early detection of circulating tumor cells, since tyrosinase is thought to be a melanocyte-specific marker.

PURPOSE

To further evaluate the clinical relevance of this potential marker, we examined peripheral blood samples from patients with malignant melanoma in different stages of disease for the presence of tyrosinase mRNA.

METHODS

Total cellular RNA was extracted from heparinized peripheral blood cells from 64 patients with malignant melanoma, from five healthy control subjects, and from four patients with other cancers using the RNAzol A method. For analysis of tyrosinase mRNA, RT-PCR was performed as previously described by Smith et al.; the sensitivity of this assay was tested using RNA extracted from human melanoma cells (SK-mel 1 and SK-mel 3 cell lines) serially diluted with peripheral blood obtained from healthy control subjects. Two additional human melanoma cell lines (SK-mel 30 and RPMI-7951) served as positive controls for RT-PCR detection of tyrosinase mRNA. Overall patient survival curves were constructed using Kaplan-Meier estimates.

RESULTS

Tyrosinase mRNA was detected by RT-PCR assay of all four of the established melanoma cell lines tested. Nine of the 64 patients with malignant melanoma were found to have detectable tyrosinase mRNA in their peripheral blood cells (tyrosinase-positive patients). The 16 patients with localized primary melanoma did not have detectable tyrosinase mRNA in their peripheral blood cells. Among the 48 patients with metastatic disease, all 27 patients who exhibited no evidence of disease progression were tyrosinase negative. Notably, all nine tyrosinase-positive patients had visceral metastases and were found to exhibit disease progression at the time of the sampling. Four of the nine tyrosinase-positive patients were also found to test negative at times without evidence of progressive disease; one patient became negative after achieving stable disease and three became positive for tyrosinase transcripts on disease progression. The probability of survival from time of sampling was significantly lower in the nine tyrosinase-positive patients when tested versus the 23 patients with comparable disease but without detectable tyrosinase mRNA (two-sided; P < or = .05).

CONCLUSIONS

The results of this study demonstrate that the detection of tyrosinase mRNA in cells in the peripheral blood by RT-PCR may be a useful prognostic marker for predicting tumor progression and poor clinical outcome in patients with malignant melanoma.

Entrainment of Syrian hamster circadian activity rhythms by neonatal melatonin injections

The circadian rhythms of fetal and neonatal rodents are entrained by their mother. This entrainment is dependent upon the maternal suprachiasmatic nucleus (SCN), but the mechanism of entrainment is unknown. Administration of the pineal hormone melatonin to pregnant, SCN-lesioned female Syrian hamsters entrains the activity rhythms of their hamster pups. The aim of this study was to determine whether melatonin injected directly in neonatal Syrian hamsters is able to entrain circadian rhythms and, if so, for how long this effect persists during development. Injection of melatonin in two groups of hamster pups at opposite phases on postnatal days 1-5 entrained the onset of activity rhythms on the day of weaning to two phases 10.67 h apart. Melatonin injection did not entrain activity rhythms to opposite phases on either postnatal days 6-10 or 21-25. Vehicle injection did not entrain animals to opposite phases at any of the ages studied. These results demonstrate that melatonin is able to act directly on the neonate to cause entrainment and that this effect disappears after postnatal day 6.

Platelet endothelial cell adhesion molecule-1 (PECAM-1): a potential prognostic marker involved in leukocyte infiltration of renal cell carcinoma

We investigated immunohistochemically the leukocyte infiltrate [CD3, CD4, CD8, CD11a, CD11b, CD14, CD56, VLA-4 and platelet endothelial cell adhesion molecule-1 (PECAM-1)] and the endothelial expression of cell adhesion molecules (PECAM-1, VCAM-1, ICAM-1 and ICAM-2) in 23 renal cell carcinoma tumor tissues. Tumors with a moderate or high density of PECAM-1 positive endothelia showed a stronger infiltration with PECAM-1-positive leukocytes as compared to tumors with a low density of positive endothelia (p<0.0085). Additionally, overall survival of patients who presented with tumors exhibiting a moderate or high density of PECAM-1 endothelia alone or in combination with a PECAM-1-positive infiltrate was extended (median survival: 23.5 months) as compared to patients without these tumor characteristics (median survival: 6.5 months). These results suggest an involvement of PECAM-1 in the process of leukocyte migration and a potential role as a prognostic marker in renal cell carcinoma.

Exposure to vinblastine modulates beta 1 integrin expression and in vitro binding to extracellular matrix molecules in a human renal carcinoma cell line

Solitary stroma-invading tumor cells expressing the ATP-binding cassette transporter P-glycoprotein have been reported to be associated with a significantly higher incidence of vessel invasion and lymph node metastases. In contrast to P-gp-mediated multidrug resistance (MDR) which has become well characterized over the last decade, little is known about further morphological and functional alterations in drug-resistant tumor cells. Binding of malignant cells to components of the extracellular matrix mediated by beta 1 integrins has been suggested to play a substantial role in the metastatic cascade. We studied alterations of beta 1 integrin expression and in vitro adhesiveness to extracellular matrix proteins of the human renal carcinoma line Caki-1 in comparison to the vinblastine resistant sublines Caki-1/V1 and Caki-1/V10 (cultured in the presence of 1 ng/ml and 10 ng/ml vinblastine, respectively). Both VLA-1 and VLA-2 receptors were acquired by the Caki-1/V10 subline, whereas untreated and Caki-1/VI cells lacked surface expression of these antigens. VLA-6 was found to be decreased in the vinblastine-resistant sublines. Attachment of drug-resistant Caki-1/V1 and Caki-1/V10 cells to collagen type I was significantly increased when compared to parental cells (p < or = 0.005). Significant differences in the attachment to type IV collagen were observed between Caki-1/V10 and untreated cells (p < or = 0.045). Both Caki-1/V1 and Caki-1/ V10 cells exhibited increased adhesion to fibronectin when compared to cells of the untreated line (p < or = 0.04). Whether an aberrant expression of beta 1 integrin receptors in resistant cells in combination with altered tumor cell adhesiveness is caused by MDR induction or whether it is an epiphenomenon of cytotoxic stress is unknown. Future studies will be needed to characterize the clinical relevance of MDR-associated changes in tumor cells.

Chromatographic techniques--the basis of doping control

The principal definition of doping, the groups of banned compounds and the basic analytical problems and strategy of doping analysis are outlined, and the position of chromatography in doping analysis is explained. Examples of the application of GC-MS, especially high-resolution MS. and of LC-thermospray MS to doping problems are given. A practical case is presented briefly, showing the post-analytical problem of evaluating even unequivocal results.

Increased serum levels of basic fibroblast growth factor (bFGF) are associated with progressive lung metastases in advanced renal cell carcinoma patients

Basic fibroblast growth factor (bFGF) has been detected in body fluids of patients with various malignancies including renal cancer. Cytoplasmatic expression of bFGF in primary renal cell carcinoma cells has been reported recently to correlate with an impaired patient survival. In the present study, we analysed the statistical association of spontaneous serum bFGF levels in 23 patients with advanced renal cell carcinoma and progressive metastasis in different organ sites. Increased bFGF serum levels (>90% percentile for healthy donors i.e., > 14 pg/ml) were found in eight patients (35%) with a mean of 24.1 pg/ml. All patients in this subgroup presented with progressive pulmonary metastases at the time of sample collection (p < or = 0.007). In a total of fifteen patients exhibiting progressive pulmonary metastasis, bFGF serum levels were found to be significantly higher when compared to patients lacking progressive lung lesions (p < or = 0.0006). Of fifteen patients with bFGF levels lower than 14 pg/ml, six showed bone metastases at the time of sample collection (p < or = 0.04). Our results suggest that increased serum bFGF levels may be associated with a higher frequency of progressive pulmonary metastases. Interactions between soluble angiogenic factors and components of the extracellular matrix or basement membranes in remote sites of metastasis will be subject to further experiments.

Gonadal responses of the male tau mutant Syrian hamster to short-day-like programmed infusions of melatonin

Changes in the duration of the nocturnal peak of the circadian rhythm of melatonin secretion by the pineal gland mediate pohotoperiodic control of reproductive cycles in mammals. The present study examined whether the tau mutation of the circadian clock of the Syrian hamster altered the ability of the animals to exhibit photoperiodic, gonadal responses to timed infusions of exogenous melatonin. Pinealectomized tau mutant and wild-type hamsters received s.c. infusions of vehicle or melatonin solution (50 ng/h) for either 8 h or 6.67 h (i.e., 83% of 8 h, a reduction by the same proportion as circadian period is shortened by the mutation, 20 h vs. 24 h) once every 20 h for 6 wk. Testicular weight and serum levels of LH and prolactin were measured to assess the effects of the infusions on the reproductive axis. Both genotypes exhibited significant gonadal regression to the 8 h and 6.67 h melatonin signals, versus saline controls, although in taus the magnitude of the response to 6.67 h melatonin was significantly greater and more consistent than in wild-types. Compared to saline-infused hamsters, animals that received infusions of melatonin of either duration showed significantly reduced serum levels of LH and prolactin. There was no significant difference between the two genotypes in the observed endocrine responses to melatonin infusions. These preliminary data demonstrate that tau mutant hamsters can respond to programmed systemic infusions of melatonin in a manner comparable to that observed in wild-type hamsters, and therefore, that the tau mutation of the circadian clock has not impaired the ability of the hamster to measure photoperiodic time, as represented by melatonin.

Methohexital impairs osmoregulation. Studies in conscious and anesthetized volume-expanded dogs

BACKGROUND

Anesthetic agents influence central regulations. This study investigated the effects of methohexital anesthesia on renal and hormonal responses to acute sodium and water loading in dogs in the absence of surgical stress.

METHODS

Fourteen experiments (two in each dog) were performed in seven well-trained, chronically tracheotomized beagle dogs kept in highly standardized environmental and dietary conditions (2.5 mmol sodium and 91 ml water/kg body weight daily). Experiments lasted 3 h, while the dogs were conscious (7 experiments) or, after 1 h control, while they were anesthetized (7 experiments) with methohexital (initial dose 6.6 mg/kg body weight and maintenance infusion 0.34 mg.min-1.kg-1 body weight) over a period of 2 h. In both experiments, extracellular volume expansion was performed by intravenous infusion of a balanced isoosmolar electrolyte solution (0.5 ml.min-1.kg-1 body weight). Normal arterial blood gases were maintained by controlled mechanical ventilation. In another five dogs the same protocol was used, and vasopressin (0.05 mU.min-1.kg-1 body weight) was infused intravenously during methohexital anesthesia.

RESULTS

Values are given as means. During methohexital anesthesia, mean arterial pressure decreased from 108 to 101 mmHg, and heart rate increased from 95 to 146 beats/min. Renal sodium excretion decreased; urine volume increased; and urine osmolarity decreased from 233 to 155 mosm/l, whereas plasma osmolarity increased from 301 to 312 mosm/l because of an increase in plasma sodium concentration from 148 to 154 mmol/l. Plasma renin activity, plasma aldosterone concentration, plasma atrial natriuretic peptide, and plasma antidiuretic hormone concentrations (range 1.8-2.8 pg/ml) did not change in either protocol. In the presence of exogenous vasopressin (antidiuretic hormone 3.3 pg/ml), water diuresis did not occur, and neither plasma osmolarity nor the plasma concentration of sodium changed.

CONCLUSIONS

Methohexital may impair osmoregulation by inhibiting adequate pituitary antidiuretic hormone release in response to an osmotic challenge.

Lymphocyte-conditioned medium in combination with interleukin-2 effectively induces antitumour autoimmunity by adoptive transfer of short activated killer (SHAK) cells

In this study, effective antitumour immunity was transferred by autologous short activated killer (SHAK) cells induced over four hours with lymphocyte conditioned medium (LCM) and recombinant interleukin-2 (rIL-2). Among eight patients with progressive metastatic renal cell carcinoma refractory to standard therapy, there were six objective tumour responses to SHAKs. Progression-free survival ranged from 0 to 8+ months, and overall survival ranged from 2 to 14+ months, with a median of 9+ months. Systemic toxicity of SHAKs was limited to flulike symptoms. Patient SHAKs provided a tumour-specific immunity, both cellular and humoral (expression and secretion of secondary cytokines, including IL-2, GM-CSF, INF-gamma and TNF-alpha), far superior to rIL-2 activated killer cells.

Behavioural and cellular responses to light of the circadian system of tau mutant and wild-type Syrian hamsters

The tau mutation shortens the free-running circadian period of the activity rhythm of the Syrian hamster from around 24 h in the wild-type, to 20 h in the homozygous mutant. The aim of this study was to examine the effects of light pulses on the activity rhythms and expression of c-fos in the suprachiasmatic nuclei of wild-type and mutant hamsters. This would make it possible to determine the relative durations of subjective day and night, and thereby characterize further the effect of the mutation upon the circadian cycle. Presentation of light pulses (15 min) to animals kept in dim red light for seven to 10 days induced phase-dependent shifts in the onset of activity. During subjective day (inactive phase) there was no effect of light upon the activity rhythm of either normal or mutant animals. Early in subjective night (i.e. after the start of the active phase), light pulses induced phase delays of approximately one circadian hour in both phenotypes. However, later in subjective night light pulses induced phase advances in activity rhythms. The magnitude of the advance phase shifts differed considerably between the two phenotypes, with the wild-types typically showing shifts of about one circadian hour, while the mutants showed much larger advances of up to 12 circadian hours. In both strains, advances were observed following light at circadian time 22 but not after light at circadian time 24. The relative duration of subjective night was therefore comparable in the mutants and wild-types i.e. around 11 circadian hours. In order to examine the light-induced expression of the immediate early gene c-fos at different circadian phases, animals received a second light pulse (15 min) or a control "dark pulse" at the same circadian time as they had received the first, but seven to 10 circadian days later. They were perfused 1 h after the start of the pulse and brains processed for the immunocytochemical detection of Fos, the protein product of c-fos. Animals receiving dark pulses showed minimal Fos immunoreactivity in the suprachiasmatic nucleus, regardless of the circadian time of presentation of the stimulus. During subjective day (circadian times 4-11), light induced very little Fos immunoreactivity. In contrast, light presented during subjective night (after circadian time 12) induced a dense pattern of Fos immunoreactivity in the ventrolateral, retino-recipient region of the suprachiasmatic nucleus of both wild-type and mutant animals.(ABSTRACT TRUNCATED AT 400 WORDS)

In vivo tumor necrosis factor-alpha as indicator of biologic and clinical response to low-dose SC recombinant interleukin 2

The effect of low-dose human recombinant interleukin-2 (rIL-2) on the induction of secondary tumor necrosis factor-alpha (TNF-alpha) in vivo was studied in 16 patients with metastatic renal cell carcinoma. In all patients s.c. rIL-2 resulted in a significant increase in TNF-alpha serum levels within 4 to 8 hours, as determined by enzyme-linked immunosorbent assay (ELISA). TNF-alpha serum concentrations remained elevated up to 24 hours following single s.c. administration of rIL-2. Total secondary TNF-alpha release, as assessed by the area under the curve (AUC), appeared to be independent of dose distribution of rIL-2 (10 million IU rIL-2 q12 hours versus 20 million IU rIL-2 q24 hours). rIL-2 induced TNF-alpha release was significantly higher in patients who had received prior rIL-2 immunotherapy, while steroids resulted in a significant suppression of TNF-alpha release. Secondary TNF-alpha release was statistically associated with progression-free survival of renal cell carcinoma patients and may be a prognostic factor in patients receiving rIL-2.

Platelet aggregation inhibiting and anticoagulant effects of oligoamines, XXIII: Influence of the oligoamine RE 1492 on the deformability of red blood cells

The influence of the oligoamine RE 1492 on the deformability of Red Blood Cells (RBCs) was measured with the micropipette aspiration technique and the capillary rigidometer. The maximal cell flow resistance (MCFR) and the apparent elastic membrane shear modulus mu were increased by 45% at RE 1492 concentrations > 10 mumol/L. There was a decrease of the surface/volume ratio of 6% at RE 1492 concentrations of 25 mumol/L. The qualitative analysis of the polypeptide pattern of membranes and extracted membranes of human RBCs suggests that the reduction of deformability is due to an increased affinity of skeletal proteins to the cytosolic part of the membrane. RE 1492 caused a decrease of osmotic hemolysis by 80% at concentrations of 8 mumol/L.

Immunocytochemical detection of P-glycoprotein: initial expression correlates with survival in renal cell carcinoma patients

We evaluated 28 patients with advanced renal cell carcinoma for the initial expression of P-glycoprotein (MDR1 gene product) employing immunocytochemistry. Tumor specimens were obtained upon primary tumor nephrectomy. In all patients, progression-free survival time following nephrectomy was evaluated and correlated statistically with the staining results. Progression-free survival of patients with no or very few (< 1%) P-glycoprotein-positive tumor cells (n = 8, median survival 27.0 months) was significantly extended (p < 0.04) as compared to patients with 1% or more P-glycoprotein-positive tumor cells (n = 20, median survival 4.0 months). Correlations with histopathological tumor characteristics were insignificant. These results suggest a potential role for P-glycoprotein as a biologic parameter predictive of tumor progression in renal cell carcinoma patients.

Soluble interleukin 2 receptors abrogate IL-2 induced activation of peripheral mononuclear cells

Soluble interleukin 2 receptors (sIL-2R) exert a potential role in immunoregulation. We investigated the in vitro effects of sIL-2R on several interleukin 2 (IL-2)-dependent cellular events. Cytotoxicity of human rIL-2-stimulated PBMC against K562 and Daudi was correlated inversely to the concentration of sIL-2R in the culture medium during rIL-2 stimulation. sIL-2R concentrations higher than 4.0 pM produced a significant loss of cytotoxicity (P < 0.01). The effect of different sIL-2R concentrations added to cultured human PBMC on secondary sIL-2R production was tested by ELISA. Secondary sIL-2R production was abrogated by high initial sIL-2R dosages whereas low initial dosages were followed by a continuing production of secondary sIL-2R after five days of culture. Proliferation of the IL-2-dependent mouse cell line CTLL-2-was suppressed by sIL-2R added to the culture medium in a dose-dependent way. The neutralizing capacity of sIL-2R strongly depended on the initial number of CTLL set in per proliferation assay. In contrast, variation of rIL-2-concentration had no significant effect on reduction of proliferation by sIL-2R. Furthermore, preincubation of sIL-2R with rIL-2 did not enhance growth suppression. These last findings indicate that there is at least no functional interaction between sIL-2R and free IL-2, whereas an interaction of sIL-2R with the membrane-bound receptor for IL-2 seems possible.

In vivo time and dose dependency of interleukin-6 secretion in response to low-dose subcutaneous recombinant interleukin-2

Serum concentrations of Interleukin-6 (IL-6) were determined in renal cell carcinoma patients treated with low-dose subcutaneous human recombinant interleukin-2 (rIL-2). In all patients, administration of rIL-2 resulted in a significant increase in IL-6 serum levels to peak values within 4 to 6 hours as measured by enzyme-linked immunosorbent assays (ELISA). Repetitive administration of rIL-2 induced significantly lower IL-6 serum peaks when compared to the initial administration of rIL-2. Cumulative IL-6 release, as expressed by the area under the concentration curve (AUC), appeared to be independent of rIL-2 dose distribution (10 million IU rIL-2/m2 versus 20 million IU rIL-2/m2), and IL-6 serum peaks showed no direct dose dependency. Prior rIL-2 immunotherapy had no measurable effect on rIL-2 induced IL-6 release, while steroids resulted in a significant suppression of secondary IL-6 did not correlate with response to rIL-2 therapy or survival of rIL-2 treated renal cell carcinoma patients.

Induction of cytokines and cytotoxicity against tumor cells by Newcastle disease virus

The use of NDV as biological adjuvant in vaccines against human cancer is still actual in several clinical treatment protocols. In this study, we have investigated in vitro-effects of Newcastle disease virus (NDV) strain 73-T on isolated mononuclear blood cells and cultured tumor cells. Cellular cytotoxicity of PBMC freshly isolated from healthy donors against tumor cells was enhanced significantly (p < 0.01) after coincubation of NDV with effector cells. NDV failed to enhance cytotoxicity of effector cells when PBMC were stimulated three days with 500 IU recombinant interleukin-2 (rIL-2) per ml prior to coincubation with the virus. No significant enhancement of cellular lysis was seen when only target cells were coincubated with NDV. As shown by depletion of various lymphocyte subsets, NK cells were the predominant mediator of lysis. Enhancement of cytotoxicity correlated with the induction of interferon-alpha (IFN-alpha) in PBMC by NDV. NDV also induced high amounts of tumor necrosis factor-alpha (TNF-alpha) in PBMC. Induction of interferon-gamma (IFN-gamma) was weak. A direct cytopathic effect (CPE) of NDV on different target cells was detected by colorimetric measurement of metabolic cell activity. The human tumor cell lines A-498, A-704, Caki-1, Caki-2, and K-562 and the fibroblast line MRC-5 showed progressive cellular destruction 48 h after infection with NDV, whereas PBMC and Daudi cells remained unaffected during the observation period. The nontransformed monkey kidney cell line CV-1 and the transformed monkey kidney cell line COS-1 were both lysed by NDV with marginal difference in time course of CPE. Our results indicate a reasonable potential of pleiotropic modifications of the immune response against tumors by NDV.

Testicular regression in pinealectomized Syrian hamsters following infusions of melatonin delivered on non-circadian schedules

The aims of this study were to validate the use of a timed infusion protocol for restoring physiologically appropriate rhythms of melatonin in the circulation of pinealectomized hamsters and, using such infusions, to compare the relative importance of the parameters of the nocturnal melatonin signal--frequency, phase, and duration of the interval between signals--in the photoperiodic control of testicular function in male Syrian hamsters. Hamsters were pinealectomized and fitted with a chronic s.c. cannula enabling them to receive timed infusions of melatonin (50 ng/h) or saline vehicle (50 microliters/h). In experiment 1, RIA of serum samples confirmed that s.c. infusions produced a pattern of melatonin in the blood equivalent in amplitude and duration to that observed previously in pineal-intact animals exposed to a short photoperiod. In experiment 2, we investigated the relative importance of the frequency of the melatonin signal and the duration of the interval between signals. Pinealectomized animals that received infusions of saline for 6 wk had large testes and high concentrations of LH in the serum. Animals that received a series of short-day-like infusions of melatonin of 14-h duration, separated by an interval of either 10 h or 6 h, underwent gonadal regression and had low serum concentrations of LH. Animals that received infusions of melatonin of 8-h duration, separated by intervals of 12 h, also exhibited full gonadal collapse. However, animals that received the same 8-h infusions separated by intervals of 8 h (i.e., once every 16 h) did not undergo gonadal regression and their circulating levels of LH remained high.(ABSTRACT TRUNCATED AT 250 WORDS)

Pretreatment natural killer antigen density correlates to clinical response in tumor patients receiving long-term subcutaneous recombinant interleukin-2 and recombinant interferon-alpha

We evaluated density of the natural killer (NK) cell-associated CD56 antigen on circulating NK cells of 47 patients with advanced renal cell carcinoma. Patients received a combination of low-dose subcutaneous recombinant interleukin-2 (rIL-2) and recombinant interferon-alpha (rIFN-alpha) as home therapy. Antigen density of CD56 before therapy was 2.2-fold higher (P < 0.005) in patients who subsequently achieved a complete or partial remission when compared with patients who presented with progressive disease on therapy. After a 6-week treatment cycle, NK cells of treatment responders expressed significantly (2.1-fold; P < 0.005) more CD56 antigens than NK cells in nonresponding patients. These results suggested a potential role of both pre- and posttreatment NK antigen density levels as a biologic correlate to treatment response.

Non-photic phase shifting of the circadian activity rhythm of Syrian hamsters: the relative potency of arousal and melatonin

This study investigated the relative potency of melatonin and arousal as Zeitgebers in the non-photic phase shifting of circadian rhythmicity in the adult Syrian hamster. Animals held under dim red light (DD) exhibited robust free-running rhythms of wheel-running activity. Melatonin (1 mg/kg) or ethanolic saline vehicle, delivered manually by subcutaneous injection after removing the animal from its cage, resulted in phase advances of the activity rhythm. This effect was phase dependent, injections at CT 8 and 10 being effective (CT 12 = anticipated activity onset), whereas injection at CT 2, 6, 14 and 20 did not cause a shift. There was no significant difference between the magnitude or timing of phase shifts in response to injections of saline or melatonin. To determine whether the observed shifts were related to arousal of the animals induced by handling, a second group held under DD were fitted with chronic s.c. cannulae so that melatonin solution or vehicle could be delivered remotely at projected CT 10. Neither solution had any effect upon the free-running rhythm. However, when these animals received manual s.c. injection of saline or melatonin solution, they exhibited phase advances similar to those observed in Expt. 1. These results fail to support the hypothesis that melatonin can exert a chemically specific, acute phase-shifting action in the adult Syrian hamster. They do, however, demonstrate the potent effect of arousing stimuli upon the circadian clock in this species.

The effect of signal frequency on the gonadal response of male Syrian hamsters to programmed melatonin infusions

The aim of this study was to investigate which characteristics of the nocturnal melatonin signal, in addition to its duration, convey photoperiodic information to the reproductive axis. To achieve control over the pattern of circulating melatonin, male Syrian hamsters held under stimulatory long daylengths (16h light:8h dark) were pinealectomized to remove the principal source of circulating endogenous hormone and then fitted with chronic subcutaneous cannulae through which programmed infusions of melatonin solution or vehicle could be delivered. Experiment 1 tested whether long intervals between successive melatonin signals impaired the photoperiodic response. Animals which received a short day-like melatonin infusion of 10 h duration once every 24 h (T = 24) for 6 weeks underwent gonadal atrophy. When the same number of signals (42) was delivered at a frequency of once every 32 h (T = 32), they were ineffective and animals remained gonadally active. Two infusion patterns were used to determine if the loss of response to 10 h signals given at T = 32 h was a consequence of the frequency per se or the long interval between signals (22 h). In the first, a 'chimaeric' signal which combined a long duration i.e. short day-like 18 h melatonin signal with a short day-like melatonin-free interval of 14 h (combined signal T = 32 h) was able to induce significant, but only partial, gonadal atrophy. Second, when the 22-h interval between 10-h melatonin signals was interrupted by a short (2 h) melatonin pulse, significant but partial gonadal regression again occurred. Moreover, the response depended upon the timing of the 2 h pulse. When this fell early in the melatonin-free interval, leaving a large portion of it intact, it had no effect on gonadal condition. In contrast, a pulse delivered in the middle of the interval, which divided it up into two short day-like segments of 10 h each, was partially effective in restoring a short day response. The second experiment tested whether melatonin signals delivered at a high frequency would induce a photoperiodic response. A 10 h infusion delivered once every 24 h caused gonadal atrophy. The same melatonin infusion delivered at a periodicity of 20 h (T = 20) was also very potent as a short day stimulus. However, when 10-h signals were delivered at the higher frequencies of once every 18 or 16 h, they were less effective. Only a minority of animals exhibited gonadal atrophy and overall the group means were not significantly different from those of saline-infused controls, but were significantly greater than those of the 24 and 20 h groups. These data demonstrate that the photoperiodic response to the melatonin signal is sensitive to the frequency at which the signal is received. However, there is no evidence for a circadian basis to this sensitivity, nor a dependence upon the relationship between the endocrine stimulus and the light-dark cycle, insofar as signals encountered at a non-circadian period of 20 h are very effective. Moreover, the effectiveness of signals encountered at longer periodicities can be modified by manipulation of the uninterrupted duration of the interval free of melatonin, demonstrating a role in photoperiodic time measurement for the duration of the interval between signals.

[A uterine rupture during peridural anesthesia]

A 31 years old multiparous woman was delivered by caesarean section at her first pregnancy. For her third, spontaneous, full-term labour an epidural analgesia was realized with 0.125% epinephrined bupivacaine and fentanyl (1 mg per kg). In spite of its initial efficacy, pains appeared only localized at the caesarean scar. An uterine rupture was suspected, due probably to the use of oxytocin. The operating room was immediately prepared for an emergency caesarean section. As none other pejorative clinical manifestation was present, vaginal delivery was pursued and an healthy boy was taken out after application of forceps. The uterine revision and the secondary laparotomy, performed under epidural anesthesia, confirmed an uterine break, not very wide. The end result was satisfactory both for the mother and the child. The use of epidural analgesia and oxytocin are discussed from the literature and the clinical facts. The absence of internal tocography is an arguable point in this case report.