Role of Sleep Apnea and Long-Term CPAP Treatment in the Prognosis of Patients With Melanoma: A Prospective Multicenter Study of 443 Patients

BACKGROUND

OSA has been associated with increased incidence and aggressiveness of melanoma. However, the long-term impact of OSA and CPAP treatment on the prognosis of melanoma remains unexplored.

RESEARCH QUESTION

Are OSA and CPAP treatment associated independently with a poor prognosis for cutaneous melanoma?

STUDY DESIGN AND METHODS

Four hundred forty-three patients with a diagnosis of cutaneous melanoma (2012-2015) underwent a sleep study within 6 months of diagnosis. The main 5-year outcome of the study was a composite of melanoma recurrence, metastasis, or mortality. Patients were divided into four groups: baseline apnea-hypopnea index (AHI) of fewer than 10 events/h (no OSA; control group), OSA treated with CPAP and good adherence, untreated or poor CPAP adherence in moderate (AHI, 10-29 events/h), and severe OSA (AHI, ≥ 30 events/h). Survival analysis was used to determine the independent role of OSA and CPAP treatment on melanoma composite outcome.

RESULTS

Three hundred ninety-one patients (88.2%) were available for analysis at 5-year follow-up (mean age, 65.1 ± 15.2 years; 49% male; Breslow index, 1.7 ± 2.5 mm). One hundred thirty-nine patients had AHI of fewer than 10 events/h (control group); 78 patients with OSA were adherent to CPAP; and 124 and 50 patients had moderate and severe OSA, respectively, without CPAP treatment. Median follow-up was 60 months (interquartile range, 51-74 months). During follow-up, 32 relapses, 53 metastases, and 52 deaths occurred (116 patients showed at least one of the main composite outcomes). After adjusting for age, sex, sentinel lymph nodes affected at diagnosis, BMI, diabetes, nighttime with an oxygen saturation below 90%, Breslow index, Epworth sleepiness scale scores, and melanoma treatment, moderate (hazard ratio [HR], 2.45; 95% CI, 1.09-5.49) and severe OSA (HR, 2.96; 95% CI, 1.36-6.42) were associated with poorer prognosis of melanoma compared with the control group. However, good adherence to CPAP avoided this excess risk (HR, 1.66; 95% CI, 0.71-3.90).

INTERPRETATION

Moderate to severe untreated OSA is an independent risk factor for poor prognosis of melanoma. Treatment with CPAP is associated with improved melanoma outcomes compared with untreated moderate to severe OSA.

Obstructive sleep apnoea is related to melanoma aggressiveness through paraspeckle protein-1 upregulation

BACKGROUND

In patients with obstructive sleep apnoea (OSA), intermittent hypoxia induces overexpression of paraspeckle component (PSPC)1, a master modulator of transforming growth factor (TGF)-β signalling, which promotes cell cancer progression through epithelial-mesenchymal transition (EMT) and acquisition of cancer stem cell (CSC)-like features. However, the persistence of intermittent hypoxia-induced effects on PSPC1, and their consequences in cancer patients are not known. To this effect, circulating PSPC1 levels were compared in patients with cutaneous melanoma with or without OSA, and their relationship with tumour aggressiveness along with the in vitro effects of soluble PSPC1 and intermittent hypoxia on melanoma cell aggressiveness mechanisms were assessed.

METHODS

In 292 cutaneous melanoma patients, sleep studies and serum levels of PSPC1 and TGF-β were evaluated. The effect of PSPC1 on expression of EMT and CSC transcription factors was assessed using melanoma cell lines with patient sera under both normoxia and intermittent hypoxia conditions.

RESULTS

PSPC1 levels were higher in patients with moderate-severe OSA compared with mild OSA or non-OSA patients. Serum levels of PSPC1 were associated with several cutaneous melanoma clinical aggressiveness indicators. Both intermittent hypoxia exposures and serum from OSA patients upregulated TGF-β expression and amplified the expression of transcription factors associated with EMT activation and acquisition of CSC characteristics.

CONCLUSION

In cutaneous melanoma patients, OSA severity is associated with higher PSPC1 serum levels, which jointly with intermittent hypoxia would enhance the self-reprogramming capabilities of EMT and CSC feature acquisition of melanoma cells, promoting their intrinsic aggressiveness.

Family Perceptions of Participating in a Structured Summer Kindergarten Transition Program

Many school districts provide one-time transition events to help students prepare for the rigors of kindergarten; yet, research shows families desire additional information and opportunities to help their children thrive once school begins. Researchers for this study interviewed 39 parents whose children participated in a three-week structured kindergarten transition program designed to promote parental involvement in school, reduce students' chronic absenteeism, and increase children's readiness for kindergarten. All interviewees expressed that participating in the program yielded benefits for themselves and their children. Respondents shared that meeting education staff members early during the summer, familiarizing themselves with the layout and routines of their schools, and building stronger social connections with other families were of particular value in helping them prepare for the start of kindergarten. Similarly, understanding kindergarten expectations more thoroughly and acquiring tools to support their children at home were deemed especially beneficial for those families who had not previously participated in preschool or other structured school opportunities. In addition to positive feedback, participants proposed various ways that adjusting the program could better meet the needs of all stakeholders. Suggestions included increasing the length of the student sessions, improving communication between district and families, re-structuring the parent information sessions to be more conducive to working families, and staffing the program with more individuals who would stay on as teachers during the transition from summer to fall. Parent suggestions from this study were synthesized into multiple implications for practice and substantiated by current relevant literature.

Proangiogenic factor midkine is increased in melanoma patients with sleep apnea and induces tumor cell proliferation

Midkine (MDK) might mediate the proangiogenic effect of intermittent hypoxia (IH) in patients with obstructive sleep apnea (OSA) and cutaneous melanoma (CM). We compare circulating MDK in CM patients with and without OSA, and their relationship with tumor aggressiveness, while exploring in vitro effects of soluble MDK on human lymphatic endothelial (HLEC) and melanoma cell proliferation. In 360 CM patients, sleep studies and MDK serum level measurements were performed. The effect of MDK on cell proliferation was assessed using HLEC and melanoma cell lines with patient sera under both normoxia and IH. MDK levels were higher in severe OSA compared to mild OSA or non-OSA patients, whereas no differences in VEGF levels emerged. In OSA patients, MDK levels correlated with nocturnal hypoxemia and CM mitotic rate. In vitro, MDK promotes HLEC proliferation under IH conditions. Moreover, cultures of the human melanoma cell line C81-61 with sera from patients with the highest MDK levels promoted tumor cell proliferation, which was attenuated after the addition of MDK antibody. These responses were enhanced by IH exposures. In conclusion, in CM patients, OSA severity is associated with higher MDK levels, which, appear to enhance both the lymphangiogenesis as the intrinsic aggressiveness of CM tumor cells.

Obesity attenuates the effect of sleep apnea on active TGF-ß1 levels and tumor aggressiveness in patients with melanoma

Active transforming growth factor-β1 (TGF-β1), a cytokine partially regulated by hypoxia and obesity, has been related with poor prognosis in several tumors. We determine whether obstructive sleep apnea (OSA) increases serum levels of active TGF-β1 in patients with cutaneous melanoma (CM), assess their relationship with melanoma aggressiveness and analyze the factors related to TGF-β1 levels in obese and non-obese OSA patients. In a multicenter observational study, 290 patients with CM were underwent sleep studies. TGF-β1 was increased in moderate-severe OSA patients vs. non-OSA or mild OSA patients with CM. In OSA patients, TGF-β1 levels correlated with mitotic index, Breslow index and melanoma growth rate, and were increased in presence of ulceration or higher Clark levels. In CM patients, OSA was associated with higher TGF-β1 levels and greater melanoma aggressiveness only in non-obese subjects. An in vitro model showed that IH-induced increases of TGF-β1 expression in melanoma cells is attenuated in the presence of high leptin levels. In conclusion, TGF-β1 levels are associated with melanoma aggressiveness in CM patients and increased in moderate-severe OSA. Moreover, in non-obese patients with OSA, TGF-β1 levels correlate with OSA severity and leptin levels, whereas only associate with leptin levels in obese OSA patients.

Monitoring spatiotemporal changes in chaperone-mediated autophagy in vivo

Autophagy malfunctioning occurs in multiple human disorders, making attractive the idea of chemically modulating it with therapeutic purposes. However, for many types of autophagy, a clear understanding of tissue-specific differences in their activity and regulation is missing because of lack of methods to monitor these processes in vivo. Chaperone-mediated autophagy (CMA) is a selective type of autophagy that until now has only been studied in vitro and not in the tissue context at single cell resolution. Here, we develop a transgenic reporter mouse that allows dynamic measurement of CMA activity in vivo using image-based procedures. We identify previously unknown spatial and temporal differences in CMA activity in multiple organs and in response to stress. We illustrate the versatility of this model for monitoring CMA in live animals, organotypic cultures and cell cultures from these mice, and provide practical examples of multiorgan response to drugs that modulate CMA.

Pre-operative anxiolysis in children through a combined pharmacological therapy with hydroxyzine and a non-pharmacological distraction technique with a clown (SONRISA): study protocol for randomised double-blind clinical trial

Background

Surgery can generate significant stress and anxiety in up to 70% of the paediatric population. There are several pharmacological and non-pharmacological strategies to reduce pre-operative anxiety in children, however, they have several side effects and the available information about them is contradictory. The role of clowns and hydroxyzine in the management of anxiety is controversial, with some studies supporting and others contraindicating both strategies.

Methods

We propose a randomised double-blind, controlled clinical trial that will evaluate the effectiveness of both interventions (hydroxyzine and clowns), alone or in combination, to reduce pre-operative anxiety (using the modified Yale scale of preoperative anxiety) in children aged 2–16 years undergoing outpatient surgery (n = 188).

Subjects will be randomised into two groups – (1) standard procedure (parental accompaniment) combined with placebo or (2) standard procedure combined with preoperative hydroxyzine. After randomisation, they will be divided by chance into two further groups, depending on the presence of clowns on the patient’s surgery day. Control of pre-operative anxiety will be determined in the four groups by a modified Yale scale of preoperative anxiety and cortisol levels. Compliance of children during induction of anaesthesia, time until anaesthesia recovery, presence of postoperative delirium and use of analgesia until discharge will be also assessed. For additional information, the children, parents and healthcare professionals involved in the study will complete a satisfaction survey.

Conclusions

This study aims to gather evidence on which of these four therapeutic options achieves the highest reduction of pre-operative anxiety with the best safety profile to allow paediatricians and anaesthesiologists to use the most effective and safe option for their patients.

Trial registration

ClinicalTrials.gov identifier: NCT03324828. Registered 21 September 2017.

Sleep-Disordered Breathing Is Independently Associated With Increased Aggressiveness of Cutaneous Melanoma: A Multicenter Observational Study in 443 Patients

BACKGROUND

Sleep-disordered breathing (SDB) has been associated with a greater incidence and mortality of cancer, although such findings are inconsistent. However, no large studies are currently available to investigate this association in patients with a specific type of cancer. This study seeks to assess potential relationships between SDB severity and aggressiveness markers of cutaneous melanoma.

METHODS

Four hundred and forty-three patients with a diagnosis of melanoma underwent a sleep study within 6 months of diagnosis. General demographics were collected, along with melanoma characteristics and polygraphic parameters consisting of the apnea-hypopnea index (AHI) and indices of both continuous and intermittent night-time oxyhemoglobin desaturation (DI4%). An exploration of independent relationships between SDB and various objective melanoma aggressiveness markers (Breslow index, presence of ulceration, presence of regression, mitotic index, stage of severity, damage to the sentinel lymph, and spreading of the melanoma) was performed.

RESULTS

Patients in the upper tertiles of AHI or DI4% were 1.94 (95% CI, 1.14-3.32; P = .022) and 1.93 (95% CI, 1.14-3.26; P = .013) times more likely, respectively, to present with aggressive melanoma (Breslow index > 1 mm) than those in the lowest tertiles of these sleep attributes after adjustment for age, sex, tumor location, and BMI. This association was particularly prominent among patients < 56 years of age with Breslow index > 2 mm. The presence of the additional markers of aggressiveness was also associated with higher AHI and DI4% values.

CONCLUSIONS

The severity of SDB was independently associated with greater aggressiveness of cutaneous melanoma, particularly among younger patients.

Preliminary Study on the Carcinogenic Activity of the Fungicide Manganese Ethylenebisdithiocarbamate in the Adult Newt, Triturus Cristatus Carnifex

Percutaneous exposure of adult newts to the fungicide manganese ethylenebisdithiocarbamate (maneb) at 3 concentration levels (0.5, 2.5 and 5.0 ppm) for a total of 19-23 weeks did not result in the induction of any neoplasms.

Synthesis and photophysical and supramolecular study of π-conjugated (diethylene glycol methyl ether) benzoateethynylene oligomers and polymers

The strong π–π interaction that governs (diethylene glycol methyl ether) benzoateethynylene macromolecules was evidenced by X-ray scattering and HRTEM.

Tuberculosis Diagnostic Committees' contribution to the National TB Program in Manila and Quezon Cities

SETTING

The Philippines Tuberculosis Diagnostic Committees (TBDCs) were created to improve the quality of diagnosis of sputum smear-negative chest radiography suggestive of pulmonary tuberculosis (sn-PTB).

OBJECTIVE

To determine current TBDC activities, obstacles and possible solutions for improvements in the quality of diagnosis of sn-PTB in Manila City and Quezon City.

DESIGN

A descriptive review of TBDC Masterlist records and interviews with TBDC members using a semi-structured questionnaire.

RESULTS

A record review of nine of 10 TBDCs was conducted, with interviews of 33 of the 49 current members. During the second and third quarters of 2009, respectively 1142 and 1563 sn-PTB cases were evaluated by the TBDCs in both cities. Of these, 53% in Manila City and 65% in Quezon City were classified as active TB patients. There were significant variations in the percentage of patients recommended for anti-tuberculosis treatment by the TBDC. The participation of its members is based on their expressed commitment to program sustainability.

CONCLUSION

TBDC activities contribute to TB control in the Philippines by ensuring the judicious use of resources. Further research to assess the contributions of TBDCs in reducing diagnostic and treatment delays, and factors affecting the sustainability of the TBDCs, is recommended.

Modeling of Changes in Atmosphere Composition in Fresh-cut Peach Packages due to Temperature Fluctuations

Storage temperature is not always constant in the distribution chain of modified atmosphere fresh food packages. A change in temperature means an alteration in the respiration rate of the product and in the gas transmission rates through the film. Because of their high metabolic activity, minimally processed products are particularly sensitive to temperature variation, and hence this study has been carried out with five cultivars of fresh-cut peaches (Prunus persica). Their respiratory activity has been determined by a closed system at 4, 15, and 25 °C. The peach segments are wrapped in microperforated films whose transmission rate is determined according to the size of the microperforations (between 100 × 130 μm and 215 × 190 μm). To quantify the effect of temperature fluctuations (5 h at 25 °C) on the O2 and CO2 concentrations of the packaging atmosphere of the product, a mathematical model has been applied. Using experimental data, it has been established that the rate of O2 consumption is a potential function of the O2 concentration, while the production of CO2 is linear. Although, all cultivars are of nonmelting fresh with no big differences in respiratory activity; these differences are accentuated with O2 concentrations greater than 10% and raising the temperature. The solution of the model provides knowledge of the behavior of the product during its nonstationary period and equilibrium once reached. The results show in all cases that the CO 2 concentration is more sensitive (increase of 5 units) to a break in the cold chain than that of O2 (reduction of 2 units).

Synthesis of fluorescent dendrimers with an oligo(phenylenevinylene) core

Novel fluorescent dendrimers of first, second, and third generation bearing a conjugated oligo(phenylenevinylene) (OPV) core and peripherial allyl chains as dendrons have been synthesized by a convergent method. The compounds have been fully characterized by 1H, 13C NMR, FTIR, UV-vis, and fluorescence spectroscopy, MALDI-TOF or FAB+ mass spectroscopy and elemental analysis. All dendrimers showed in solution a blue fluorescence with a maximum wavelength at 444-446 nm and can be deposited as thin films emitting in the blue-green region. The most homogeneous films were obtained for the second generation dendrimer which also exhibits the higher quantum yield in solution. These properties make it a possible candidate for application in organic light emitting diodes (OLEDs).

Low-dose CT: a useful and accessible tool for the early diagnosis of lung cancer in selected populations

OBJECTIVE

An evaluation is made of the effectiveness of low-dose computed tomography (LDCT) in diagnosing early stage lung cancer in the Autonomous Community of Madrid (Spain).

METHODS

The study comprised subjects over 50 years of age who were active smokers (or who had stopped smoking up to 6 months previously) who smoked more than 30 cigarettes daily for at least 15 years, or 20 cigarettes daily for 20 years, or more than 10packs/year and in contact with asbestos at work. The study group was evaluated using LDCT. For all participants in whom LDCT showed no pathological findings, or in those cases classified as benign, a new LDCT scan was performed 2 years after the first. In case of doubt regarding the benign nature of the findings, an assessment algorithm was applied.

RESULTS

Among the initial 482 candidates in the study group, 466 LDCT scans were performed at baseline, revealing 9 extrapulmonary lesions and 114 pulmonary lesions in 98 subjects. The latter raised diagnostic doubts in 32 cases; of these, 15 were confirmed as benign by high resolution computed tomography (HRCT). In the remaining 17 cases, stage IAp adenocarcinoma was diagnosed at baseline (0.2%). With LDCT after 2 years, an additional four adenocarcinomas were diagnosed-all in stage IAp (0.98%). The complete study, including prevalence cut-off and incidence calculation after 2 years, resulted in the diagnosis of five cancers (1.1%) and two false positive cases (28%).

CONCLUSIONS

The use of low-dose computed tomography in risk groups is valid for the early diagnosis of bronchogenic cancer. Nevertheless, significant problems remain, particularly those associated with false positive interpretations. The results of randomized studies on lung cancer mortality such as the US NLST trial and the Dutch-Belgian NELSON trial have to be awaited before any conclusion regarding the effectiveness of LDCT screening can be drawn.

Competitive and uncompetitive inhibitors simultaneously acting on an autocatalytic zymogen activation reaction

The time course of the residual enzyme activity of a general model consisting of an autocatalytic zymogen activation process inhibited by an irreversible competitive inhibitor and an irreversible uncompetitive inhibitor has been studied. Approached analytical expressions which furnish the time course of the residual enzyme activity from the onset of the reaction depending on the rate constants and initial concentration have been obtained. The goodness and limitations of the analytical equations were checked by comparing with the results obtained from the numerical integration, i.e. with the simulated progress curves. A dimensionless parameter giving the relative contributions of both the activation and the inhibitions routes is suggested, so that the value of this parameter determines whether the activation or the inhibitions routes prevail or if both processes are balanced during the time for which the analytical expressions are valid. The effects of the initial zymogen, free enzyme and inhibitors concentrations are analysed. Finally an experimental design and kinetic data analysis is proposed to evaluate simultaneously the kinetic parameters involved and to discriminate between different zymogen activation processes which can be considered particular cases of the general model.

Deaths: final data for 1999

OBJECTIVES

This report presents final 1999 data on U.S. deaths and death rates according to demographic and medical characteristics. Trends and patterns in general mortality, life expectancy, and infant and maternal mortality are also described. A previous report presented preliminary mortality data for 1999.

METHODS

In 1999 a total of 2,391,399 deaths were reported in the United States. This report presents tabulations of information reported on the death certificates completed by funeral directors, attending physicians, medical examiners, and coroners. Original records are filed in the State registration offices. Statistical information is compiled into a national data base through the Vital Statistics Cooperative Program of the National Center for Health Statistics (NCHS), Centers for Disease Control and Prevention. For the first time in a final mortality data report, age-adjusted death rates are based upon the year 2000 population and causes of death are processed in accordance with the Tenth Revision of the International Classification of Diseases (ICD-10).

RESULTS

The 1999 age-adjusted death rate for the United States was 881.9 deaths per 100,000 standard population, a 0.7 percent increase from the 1998 rate, and life expectancy at birth remained the same at 76.7 years. For all causes of death, age-specific death rates rose for those 45-54 years, 75-84 years, and 85 years and over and declined for a number of age groups including those 5-14 years, 55-64 years, and 65-74 years. Aortic aneurysm and dissection made its debut in the list of leading causes of death and atherosclerosis exited from the list. Heart disease and cancer continued to be the leading and second leading causes of death. The age-adjusted death rate for firearm injuries decreased for the sixth consecutive year, declining 6.2 percent between 1998 and 1999. The infant mortality rate, 7.1 infant deaths per 1,000 live births, was not statistically different from the rate in 1998.

CONCLUSIONS

Generally, mortality continued long-term trends. Life expectancy in 1999 was unchanged from 1998 despite a slight increase in the age-adjusted death rate from the record low achieved in 1998. Although statistically unchanged from 1998, the trend in infant mortality has been of a steady but slowing decline. Some mortality measures for women and persons 85 years and over worsened between 1998 and 1999.

Analysis of pesticide residues in wine by solid-phase extraction and gas chromatography with electron capture and nitrogen-phosphorus detection

A feasible and reproducible method for multiresidue analysis of several common pesticides, of different polarities, in wine samples is proposed. The method combines a solid-phase extraction on polymeric cartridges eluted with ethyl acetate and a gas chromatographic determination using electron capture and nitrogen-phosphorus detection. To avoid the matrix effect, previous washing of the cartridges with a mixture of water-2-propanol (90:10) and further clean-up of the extract on Florisil cartridges, together with a calibration using spiked extracts, are recommended.

Evolutive behavior towards cardiomyopathy of treated (nifurtimox or benznidazole) and untreated chronic chagasic patients

The aim of this work was to compare the evolution of chronic chagasic untreated patients (UTPs) with that of benznidazole or nifurtimox-treated patients (TPs). A longitudinal study from a low endemic area (Santa Fe city, Argentina) was performed during an average period of 14 years. Serological and parasitological analyses with clinical exams, ECG and X-chest ray were carried out. At the onset, 19/198 infected patients showed chagasic cardiomyopathy (CrChM) while 179 were asymptomatic. In this latter group the frequency of CrChM during the follow-up was lower in TPs compared with UTPs (3.2% vs 7%). Within the CrChM group, 2/5 TPs showed aggravated myopathy whereas this happened in 9/14 UTPs. Comparing the clinical evolution of all patients, 5.9% of TPs and 13% of UTPs had unfavourable evolution, but the difference is not statistically relevant. Serological titers were assessed by IIF. Titers equal to or lower than 1/64 were obtained in 86% of the TPs, but only in 38% of UTPs. The differences were statistically significant (geometric mean: 49.36 vs. 98.2). Antiparasitic assessment of the drugs (xenodiagnosis) proved to be effective. The low sensitivity in chronic chagasic patients must be born in mind. Despite treated patients showed a better clinical evolution and lower antibody levels than untreated ones, it is necessary to carry on doing research in order to improve therapeutic guidelines, according to the risk/benefit equation and based on scientific and ethical principles.

Airway hyperresponsiveness to ultrasonically nebulized distilled water in subjects with tetraplegia

The majority of otherwise healthy subjects with chronic cervical spinal cord injury (SCI) demonstrate airway hyperresponsiveness to aerosolized methacholine or histamine. The present study was performed to determine whether ultrasonically nebulized distilled water (UNDW) induces airway hyperresponsiveness and to further elucidate potential mechanisms in this population. Fifteen subjects with SCI, nine with tetraplegia (C4-7) and six with paraplegia (T9-L1), were initially exposed to UNDW for 30 s; spirometry was performed immediately and again 2 min after exposure. The challenge continued by progressively increasing exposure time until the forced expiratory volume in 1 s decreased 20% or more from baseline (PD20) or the maximal exposure time was reached. Five subjects responding to UNDW returned for a second challenge 30 min after inhalation of aerosolized ipratropium bromide (2.5 ml of a 0.6% solution). Eight of nine subjects with tetraplegia had significant bronchoconstrictor responses to UNDW (geometric mean PD20 = 7.76 +/- 7.67 ml), whereas none with paraplegia demonstrated a response (geometric mean PD20 = 24 ml). Five of the subjects with tetraplegia who initially responded to distilled water (geometric mean PD20 = 5.99 +/- 4.47 ml) were not responsive after pretreatment with ipratropium bromide (geometric mean PD20 = 24 ml). Findings that subjects with tetraplegia are hyperreactive to UNDW, a physicochemical agent, combined with previous observations of hyperreactivity to methacholine and histamine, suggest that overall airway hyperresponsiveness in these individuals is a nonspecific phenomenon similar to that observed in patients with asthma. The ability of ipratropium bromide to completely block UNDW-induced bronchoconstriction suggests that, in part, airway hyperresponsiveness in subjects with tetraplegia represents unopposed parasympathetic activity.

Inhibitory effect of propranolol on lipid synthesis in gonadectomized male hamster flank organs

BACKGROUND

This paper describes the inhibitory effect produced by propranolol pre-treatment on lipid synthesis in flank organs from intact, gonadectomized, and isoproterenol-treated male hamsters. Furthermore, the effect induced by the same treatments on gland sebum composition is reported.

METHODS

Different groups of male hamsters were injected daily with propranolol, isoproterenol or propranolol plus isoproterenol. Treatment-effect was evaluated determining the in vitro incorporation of radioactive acetate into lipids in hamster flank organs from intact and castrated animals. Additionally, radiolabeled lipids were isolated and identified using TLC and autoradiography as methods.

RESULTS

Results demonstrate that castration significantly decreases lipid synthesis in male hamster flank organs. In addition, propranolol treatment inhibits such synthesis in glands from intact, gonadectomized, and isoproterenol-treated animals. However, isoproterenol treatment was ineffective when compared to intact or gonadectomized control vehicle-treated animals. Lipid classes isolated and identified lipids either in castrated or in drug-treated animals were phospholipids, cholesterol, monoglycerides, fatty acids, waxes and cholesterol esters.

CONCLUSIONS

Results indicate an inhibitory effect induced on lipid synthesis by beta-adrenergic receptor antagonists; however, beta-adrenergic agonists drugs do not stimulate it. Data suggest a permissive role of adrenergic hormones on lipid synthesis in intact and in gonadectomized animals. Furthermore, castration decreased the synthesis, suggesting that a tight coupling between beta-adrenergic receptors and androgen receptors may be a prerequisite for lipogenesis in this tissue. Pre-treatment does not modify sebum composition in gonadectomized animal glands. These data support the evidence that activation of beta-adrenergic receptors could be an independent factor in the lipid composition regulation process.

Evaluation of the tumor-promoting activity of two beta-adrenoreceptor blocking agents, propranolol and atenolol, in liver of Fischer 344 rats

The tumor-promoting activity of two beta-adrenoreceptor blocking agents, propranolol and atenolol, was tested in a two-stage protocol of hepatocarcinogenesis in male and female Fischer 344 rats. Propranolol is a lipophilic non-selective beta-blocker mainly eliminated via the liver; atenolol is a hydrophilic beta 1-selective blocking agent, mainly eliminated via the kidney. Animals were initiated with a single dose of diethylnitrosamine (DEN, 200 mg/kg, i.p.) and, after 17 days of recovery, were continuously treated with propranolol (75-100 mg/kg) or atenolol (300 mg/kg) by gavage for up to 21 months. Rats given phenobarbital (0.05% in the diet) were used as positive controls. After 2, 4 and 8 months of promotion, preneoplastic lesions were quantified by staining sections of liver for gamma-glutamyltranspeptidase (GGT). In non-initiated rats, neither propranolol nor atenolol influenced the development of spontaneous preneoplastic or neoplastic liver lesions. The results obtained in DEN-initiated rats given propranolol cannot be unequivocally interpreted. In the male, propranolol seemed to be ineffective. In the female, there was weak enhancement of DEN-induced GGT foci at 4 and 8 months and of neoplastic lesions thereafter. However, there was great interindividual variability in focus and tumor yields. Unfortunately, due to the high incidence of liver tumors in rats given DEN alone and the small number of propranolol-treated rats that survived until the end of the experiment, no definite conclusion can be drawn about the modifying potential of this beta-blocker on liver carcinogenesis. There was no evidence of liver tumor promotion in DEN-initiated rats of either sex given atenolol.