Incidence and time trends of childhood hematological neoplasms: a 36-year population-based study in the southern European context, 1983-2018

BACKGROUND

Hematological neoplasms (HNs) are the first and most common childhood cancers globally. Currently, there is a lack of updated population-based data on the incidence of these cancers in the Spanish pediatric population. This study aimed to describe the incidence and incidence trends of HNs in children (0-14 years) in Spain using data from the Spanish Network of Cancer Registries and to compare the results with other southern European countries.

METHODS

Data were extracted from 15 Spanish population-based cancer registries between 1983 and 2018. Cases were coded according to the International Classification of Diseases for Oncology, third edition, first revision, and grouped according to the International Classification of Childhood Cancer, third edition. Crude rates (CRs), age-specific rates, and age-standardized incidence rates using the 2013 European population (ASRE) were calculated and expressed as cases per 1,000,000 child-years. Incidence trends and annual percentage changes (APCs) were estimated.

RESULTS

A total of 4,747 HNs were recorded (59.5% boys). Age distribution [n (%)] was as follows: <1 year, 266 (5.6%); 1-4 years, 1,726 (36.4%); 5-9 years, 1,442 (30.4%); and 10-14 years, 1,313 (27.6%). Leukemias were the most common group, with a CR and an ASRE of 44.0 (95%CI: 42.5; 45.5) and 44.1 (95%CI: 42.6; 45.7), respectively. The CR and ASRE of lymphomas were 20.1 (95%CI: 19.1; 21.1) and 20.0 (95%CI: 19.0; 21.1), respectively. The comparable incidence rates between our results and those of other southern European countries were similar for lymphomas, while some differences were observed for leukemias. From 1988 to 2016, the trend in leukemia incidence was stable for both sexes, with an APC of 0.0 (95%CI: -0.5; 0.7), whereas a constant overall increase was observed for lymphoma in both sexes, with an APC of 1.0 (95%CI: 0.4; 1.6).

CONCLUSION

Leukemias are the most common HNs in children, and their incidence has remained stable since 1988, whereas the incidence of lymphomas has increased every year. Lymphoma incidence is like that of other southern European countries, while leukemia incidence is similar only to that of southwestern European countries. Collaborative cancer registry projects allow for assessing epidemiological indicators for cancers such as HNs, which helps health authorities and clinicians provide more knowledge about these malignancies.

Comparative clinical prognosis of massive and non-massive pulmonary embolism: A registry-based cohort study

AIMS

Little is known about the prognosis of patients with massive pulmonary embolism (PE) and its risk of recurrent venous thromboembolism (VTE) compared with non-massive PE, which may inform clinical decisions. Our aim was to compare the risk of recurrent VTE, bleeding, and mortality after massive and non-massive PE during anticoagulation and after its discontinuation.

METHODS AND RESULTS

We included all participants in the RIETE registry who suffered a symptomatic, objectively confirmed segmental or more central PE. Massive PE was defined by a systolic hypotension at clinical presentation (<90 mm Hg). We compared the risks of recurrent VTE, major bleeding, and mortality using time-to-event multivariable competing risk modeling. There were 3.5% of massive PE among 38 996 patients with PE. During the anticoagulation period, massive PE was associated with a greater risk of major bleeding (subhazard ratio [sHR] 1.72, 95% confidence interval [CI] 1.28-2.32), but not of recurrent VTE (sHR 1.15, 95% CI 0.75-1.74) than non-massive PE. An increased risk of mortality was only observed in the first month after PE. After discontinuation of anticoagulation, among 11 579 patients, massive PE and non-massive PE had similar risks of mortality, bleeding, and recurrent VTE (sHR 0.85, 95% CI 0.51-1.40), but with different case fatality of recurrent PE (11.1% versus 2.4%, P = .03) and possibly different risk of recurrent fatal PE (sHR 3.65, 95% CI 0.82-16.24).

CONCLUSION

In this large prospective registry, the baseline hemodynamic status of the incident PE did not influence the risk of recurrent VTE, during and after the anticoagulation periods, but was possibly associated with recurrent PE of greater severity.

D-dimer levels and risk of recurrence following provoked venous thromboembolism: findings from the RIETE registry

BACKGROUND

Patients with venous thromboembolism (VTE) secondary to transient risk factors may develop VTE recurrences after discontinuing anticoagulation. Identifying at-risk patients could help to guide the duration of therapy.

METHODS

We used the RIETE database to assess the prognostic value of d-dimer testing after discontinuing anticoagulation to identify patients at increased risk for recurrences. Transient risk factors were classified as major (postoperative) or minor (pregnancy, oestrogen use, immobilization or recent travel).

RESULTS

In December 2018, 1655 VTE patients with transient risk factors (major 460, minor 1195) underwent d-dimer measurements after discontinuing anticoagulation. Amongst patients with major risk factors, the recurrence rate was 5.74 (95% CI: 3.19-9.57) events per 100 patient-years in those with raised d-dimer levels and 2.68 (95% CI: 1.45-4.56) in those with normal levels. Amongst patients with minor risk factors, the rates were 7.79 (95% CI: 5.71-10.4) and 3.34 (95% CI: 2.39-4.53), respectively. Patients with major risk factors and raised d-dimer levels (n = 171) had a nonsignificantly higher rate of recurrences (hazard ratio [HR]: 2.14; 95% CI: 0.96-4.79) than those with normal levels. Patients with minor risk factors and raised d-dimer levels (n = 382) had a higher rate of recurrences (HR: 2.34; 95% CI: 1.51-3.63) than those with normal levels. On multivariate analysis, raised d-dimers (HR: 1.74; 95% CI: 1.09-2.77) were associated with an increased risk for recurrences in patients with minor risk factors, not in those with major risk factors.

CONCLUSIONS

Patients with raised d-dimer levels after discontinuing anticoagulant therapy for VTE provoked by a minor transient risk factor were at an increased risk for recurrences.

Spanish validation of the PAS-ADD Checklist Questionnaire for people with intellectual disabilities for Spanish population

BACKGROUND

The Psychiatric Assessment Schedule for Adult with Developmental Disability (PAS-ADD) is an international reference tool for the diagnosis and assessment of mental health problems and behavioural disorders among people with intellectual disabilities. Although the original PAS-ADD instrument has been validated in the Spanish language, the shorter PAS-ADD Checklist has yet not been validated. The aim of this study is to validate the PAS-ADD Checklist for the Spanish population.

METHODS

The PAS-ADD Checklist Questionnaire was administered to 208 adults with intellectual disabilities at a vocational centre in Madrid, Spain. The psychometric analyses included internal consistency, inter-rater and test-retest reliability, Varimax rotation factor analysis for construct validity, criterion validity and feasibility.

RESULTS

The Cronbach's alpha was 0.80 for the overall questionnaire and between 0.40 and 0.79 for the subscales. The Kappa coefficients for test-retest and inter-rater reliability were between 0.66 and 0.80. Varimax rotation factor analysis showed five well-defined factors. The Kappa coefficients for criterion validity were between 0.30 and 0.70. Feasibility was also good.

CONCLUSIONS

The PAS-ADD Checklist is a feasible and reliable instrument for carrying out initial assessment of the mental health status of adults with intellectual disabilities, referring cases to more specialised diagnosis and treatment.

Genome sequence of a divergent Colombian isolate of potato virus V (PVV) infecting Solanum phureja

Deep sequencing analysis of the transcriptome of a Solanum phureja cv. Criolla Colombia plant with symptoms typical of a virus disease revealed an infection with potato virus V (PVV). The PVV-phureja genome comprises 9904 nt, exhibits 83% nucleotide identity with currently fully sequenced PVV isolates and contains one large ORF that codes for a polyprotein of 3065 residues flanked by 5' and 3' UTR of 217 and 448 nt, respectively. Phylogenetic analysis of the PVV-phureja polyprotein indicates that it is divergent with respect to most PVV isolates. This is the first complete PVV genome of an isolate infecting a host different to S. tuberosum and, to this date, the only one from the South American Andes.

[A successful pregnancy in female after simultaneous kidney-pancreas transplantation]

The effects of pregnancy on kidney transplant recipients have been widely described, although its impact on the mother, the fetus and the graft is still debated. Experience in simultaneous kidney-pancreas transplantation is limited, with few reported cases, which increases uncertainty about guidelines to follow in this situation. We describe a case of successful pregnancy in a 35 year-old patient who underwent simultaneous pancreas-kidney transplantation 34 months before delivery. After modifications in immunosuppressive therapy (with tacrolimus and mycophenolate, the latter being switched to azathioprine), pregnancy evolved favourably. Delivery was by caesarean section due to fetal distress at 38 weeks of gestational age. Five months after delivery the child shows normal development while both pancreas and kidney grafts show normal function.

Dediazoniation of p-hydroxy and p-nitrobenzenediazonium ions in an aqueous medium: Interference by the chelating agent diethylenetriaminepentaacetic acid

We have made a comparative study of the dediazoniation of p-hydroxy and p-nitrobenzenediazonium ions. The electron-withdrawing and donating properties of the -NO2 and -OH groups strongly determine the reactivity of both compounds, thus exerting different influences upon the dediazoniation reaction. We describe here how the decomposition of p-hydroxy and p-nitrobenzenediazonium ions in a neutral aqueous medium follows a different pattern in the presence of the metal-chelator diethylenetriaminepentaacetic acid (DTPA). The decomposition rate of p-hydroxybenzene diazonium decreases whilst the decomposition of the p-nitrobenzenediazonium ion is enhanced. The experimental data are discussed with reference to a common scheme of interference for both benzenediazonium ions in the light of the radical-scavenging capacity of DTPA.Key words: p-hydroxybenzenediazonium ion, p-nitrobenzenediazonium ion, di-ethylenetriaminepentaacetic acid, dediazoniation, radical scavenging, artifacts.

[Condom use among the young engaging in vaginal intercourse]

OBJECTIVE

To describe young people's use of condoms in penetrative vaginal intercourse, and to identify the factors associated with this use.

METHOD

The information was collected using a self-administered questionnaire put in 1,000 people between 14 and 24 years of age resident in the region of Andalusia (Spain). The results of the sample were representative and the trust interval was 95%. A bivariante analysis was carried out and hierarchical logistic regression equations were adjusted to verify associations between the dependent variable use of the condom in the vaginal intercourse and the variables proposed from PRECEDE model (predisposing, enabling, and reinforcing). The adjustment of the model was of a 38%, according to the Nagelkerke's statistic.

RESULTS

Of the people surveyed, 750 had affective and/or sexual relations with physical contact, and 63% of these had vaginal intercourse (47% of all surveyed). Of those, people that only had vaginal intercourse once (12% of all surveyed), 83% (10,3% of all surveyed) used a condom, whereas, people that had sex more than once (34% of all surveyed), 49% always used a condom (16,9% of all surveyed). The variables associated with always using a condom were: intention of safe behaviour with their regular partner and low frequency of practice. The variables associated with never using a condom were: living emancipated, having an external locus of control (thinking that becoming infected depends upon external factors), low number of zones of the body identified as pleasure-sensitive, thinking that a condom is not necessary if one trusts his or her partner, intention of unsafe behaviour with their regular partner, and not talking with the partner about preventive methods before having sex.

DISCUSSION

The most associated factors with using or not a condom in vaginal intercourse are predisposing (attitudes, values and believes) that are related with the kind of sexual partner. Interventions (based on the young active participation) are suggested to make them perceived the compatibility between the trust with the partner and the use of condom, and put in doubt the false safety given by a partner perceived as habitual.

[Professionals and managers in face of training]

OBJECTIVES

To analyse ongoing education within primary care teams from managers' perspective.

DESIGN

Cross-sectional descriptive study.

SETTING

The Mother-Infant Health Programme of Andalusia in primary care.

INTERVENTION

The views of health centre professionals were obtained through 8 groups. The type of health district and the number of years in operation were used as criteria for division. The views of the area managers were collected through a self-filled questionnaire from all the managers in the autonomous community.

MEASUREMENTS AND MAIN RESULTS

Professionals believed it necessary to keep up to date and train in new technology. They thought that training activities should focus on questions such as evaluation of programmes, focus of risk, counselling and communication, and certain techniques such as IUD insertion. Both managers and professionals coincided in recognising the effect of training on the development of mother-child services. There was consensus among professionals in affirming that training increases the quality of care delivered. Access to training was the main incentive element used by most area managers and one of those most highly valued by professionals. The professionals affirmed that in recent years there had been obstacles to their education by attending scientific events outside their areas. Many professionals stated that the economic assistance of the pharmaceutical industry for courses caused inequalities between doctors and nurses in access to training. Professionals were very critical of training combined with specialist training.

CONCLUSIONS

Professionals think they have sufficient training for mother-child health care. It is generally recognised that family doctors are better trained for working on health programmes than other professionals at the centres. Ongoing training was rated very highly by both professionals and directors, as it was seen as a motivating element and thought to be an activity almost solely carried out at health centres.

[Laboratory diagnosis and serologic course in patients with tularemia]

BACKGROUND

Tularemia was practically unknown in Spain until the end of 1997, when an epidemic outbreak was declared. This paper presents the data on microbiological diagnosis of 55 patients who suffered from tularemia.

PATIENTS AND METHODS

Thirty-two samples from 19 patients and 151 serum samples from 55 patients were obtained for culture. Serologic diagnosis was performed by tube sero-agglutination and microagglutination. Three types of tests were performed on all sera: Wright sero-agglutination (WSA), Coombs test against Brucella spp. and sero-agglutination against Yersinia enterocolitica O:3, Yersinia enterocolitica O:3, and Proteus OX 19.

RESULTS

F. tularensis was found in two samples (6.25%) of the 32 received. Titers > or = 1/160 were obtained in 78.2% and 74.5% of the initial sera by tube sero-agglutination and microagglutination, respectively. Correlation between the two tests was 0.80 (p < 0.001). Prozone phenomenon was observed in 59.9% of the sera, while crossed reactivity to Brucella spp. and Proteus spp. was found in 9.3% and 22.8%, respectively. No crossed reactivity was observed with Yersinia spp.

CONCLUSIONS

Culture of F. tularensis has low sensitivity. The correlation obtained between tube sero-agglutination and microagglutination is good. Both techniques are useful in routine diagnosis of tularemia, although microagglutination has some advantages over tube agglutination.

[Professionals and managers on internal communication in the Program of Mother-Child Health of Andalucia. Evaluation Team of the PSMI]

OBJECTIVE

To find the views of primary health area directors and of professionals in health centres (HC) in Andalusia on internal communication within the Mother-Child Health Programme introduced in this autonomous community.

DESIGN

Descriptive study that uses qualitative and quantitative methodology.

SETTING

Primary care (PC) areas and HC in Andalusia, between July 1994 and February 1995.

PARTICIPANTS

51 PC area directors and 91 HC professionals.

MEASUREMENTS AND MAIN RESULTS

Self-administered questionnaire (directors) and focus groups (professionals) were used. Analysis by non-parametric tests compared averages and analysed discourse contents. Internal communication was an important weakness in the Mother-Child Health Programme and in PC in general. There were important differences between the perceptions of directors and professionals in relation to the guidelines of the Mother-Child Programme. As such, in all the area administrations it was affirmed that there were programme objectives agreed with the professionals, and transmission channels for these objectives between the area and the centres, although these were transmitted in writing in under 25% of the areas. However, professionals thought that the objectives and guidelines of the programme were unclear and ill-defined. In addition, the view that the annual objectives are not negotiated was quite common.

CONCLUSIONS

Internal communication in PC is a considerable weakness in HC management. The professionals perceive considerable conflicts of interest between them and the organisation's directors.

Evaluation of six serological tests in diagnosis and postoperative control of pulmonary hydatid disease patients

Latex agglutination (LA), passive hemagglutination (PHA), immunoelectrophoresis (IEP) and specific IgE, IgM, IgG enzyme-linked immunosorbent assay (ELISA) tests for diagnosis and postoperative follow-up of 79 patients with surgically confirmed pulmonary hydatidosis were evaluated. Specific IgG ELISA was the most sensitive test (83.5%) and the least sensitive tests were specific IgE ELISA (44.3%) and IEP (50.6%). The specificity obtained for all the serologic test was above 97% in all cases. The greatest number of false positives in all tests (except IEP) occurred in patients with Taenia saginata and Taenia solium cysticerci infestations and in patients with lymphoma and leukemia. Specific IgG ELISA demonstrated the highest negative predictive value (93.8%). No statistically significant differences (p > 0.050) were found in the sensitivity of the tests when patients with only one cyst and patients with various cysts were compared. Considering only the patients without relapse, the percentage of seropositive patients increased in all tests at 1 and 3 months after surgery. After that time the percentage of seropositive patients decreased. At 48 months after surgery all patients without relapse became negative in IEP, specific IgE ELISA, and specific IgM ELISA. The antibody titers in all seropositive patients increased during the 3 months after surgery. From these 3 months onward, antibody levels decreased in all serologic tests studied in the group of patients without relapse. The patients who had relapses during the first year after surgery presented persistently elevated antibody titers in all postoperative sera. The antibody titers of the patients who relapsed between the third and fourth years after surgery decreased progressively the third month after surgery, and increased in the serum obtained at the moment of relapse diagnosis. Our results show that persistence of elevated antibody titers in patients with pulmonary hydatidosis in the year after surgery or titer increase after a progressive decrease are indicative of relapse or reinfection.

Spi-1/PU.1 proto-oncogene induces opposite effects on monocytic and erythroid differentiation of K562 cells

Spi-1/PU.1 is a hematopoietic transcription factor of the Ets family. To analyze the effects of ectopic expression of spi-1 on the proliferation/differentiation of human myeloid leukemia cells, K562 cells were stably transfected with a spi-1 expression vector. The transfected cell lines expressed elevated levels of spi-1 mRNA and protein and high Spi-1-DNA binding activity. The spi-1 transfected cells showed reduced growth rates and reduced clonogenic cell growth. When the erythroid and monocytic differentiation markers were analyzed, spi-1 overexpression resulted in opposite effects: erythroid differentiation was significantly inhibited in spi-1 transfectants, while spi-1 overexpression increased the monocytic differentiation of cells. These results indicate a differential role of Spi-1 on the differentiation of human myeloid leukemia cells.

[Motivation and incentives: different perceptions of administrators and professionals. Evaluation Team of the Materno-Infantile Health Program]

OBJECTIVE

To find the views of Primary Care District managers and Health Centre (HC) professionals in Andalusia on systems of motivation and incentive in use in this autonomous community.

DESIGN

A descriptive study which uses qualitative and quantitative methodology.

SETTING

Primary Care districts and Health Centres in Andalusia.

PARTICIPANTS

Primary Care district managers (51) and HC professionals (91).

MATERIAL AND METHODS

Information-gathering: self-administered questionnaire (managers) and focus groups (professionals).

ANALYTICAL TECHNIQUES

Non-parametric tests to compare means and analysis of contents of discourse. Field-work. July 1994 and February 1995.

RESULTS

55% of the district managers thought that the incentive systems in use were inadequate and insufficient. Enabling professionals to be trained is the main motivating and incentive mechanism in place. Variable productivity was the next most common mechanism. However, variable productivity, in the view of the professionals, was the main demotivating factor of recent years. Professionals thought that the economic rewards of the incentives system were slight, the target variables were unsuitable, there were no objective evaluation mechanisms and the economic differences between the incentives earned by managers and professionals were too great.

CONCLUSIONS

The District managers indicated that improvements in the incentives systems used are needed. The HC professionals affirmed that the Andalusian incentives system has demotivated Primary Care teams and has had little effect on orienting professional practice.

[Genotypes of hepatitis C virus: their relationship with risk factors, the severity of liver disease, and the serologic response]

BACKGROUND

The objective of our study was to ascertain the prevalence of different HCV genotypes between the hepatitis C patients in the health area of Monforte de Lemos, Spain, as well as the possible influence of risk factors on their distribution and their relation with hepatic disease and with the serologic response.

PATIENTS AND METHODS

We have studied 128 patients with hepatitis C. Of these, 41 were intravenous drug users (IVDU), 19 had received transfusions, 7 were hemodialyzed and in 61 the risk factors were unknown. Antibodies against HCV were detected by second-generation enzyme immunoassay (EIA) and confirmed by immunoblot. RNA-HCV presence was studied by reverse transcription-PCR (RT-PCR), and a reverse hybridization test of the amplifications was used for the genotyping.

RESULTS

Hepatitis C genotypes 1b (46.1 [8.6%]), 1a (23.4 [7.3%]) and 3a (13.3 [5.9%]) were the most frequently encountered genotype. Genotype 1a (48.8 [15.3%]) was the most prevalent genotypes in IVDU patients, while 1b was the most frequent in patients of unknown risk factors (62.3 [12.1%]). Alanine-aminotransferase (ALT) was elevated in 66.6 (17.7%) of patients with genotype 1a, in 87.5 (8.6%) of patients with genotype 1b (p = 0.0367) and in 94.1 (11.2%) of patients with genotype 3a (p = 0.0347). Subtype 1b was present in 6 of 7 cases of cirrhosis (85.7%) and in 7 of 12 cases of active chronic hepatitis (58.3%). No significant statistical differences were observed between the genotypes and the specific IgM response against core antigen of HCV, neither we observed differences in the serologic response against C1, C2, NS3 and NS4 peptides.

CONCLUSIONS

Hepatitis C genotypes 1a and 3a were the most prevalent genotypes between IVDU patients while genotype 1b was the most frequent between non-IVDU patients. Genotype 1b was associated to severe liver disease. Percentage of positivity or the reactivity against HCV peptides was independent of the genotype encountered in the patient.

Antibiotic treatment in preterm labor and intact membranes: a randomized, double-blinded, placebo-controlled trial

Although an association between microbial invasion of amniotic cavity and preterm birth has been extensively demonstrated, there is conflicting evidence regarding the benefits of antibiotic therapy in patients with preterm labor and intact membranes. We attempted to assess the efficacy of amoxicillin and erythromycin on pregnancy outcome in those patients. A randomized, double-blinded, placebo-controlled trial was designed and implemented. A total of 196 patients with singleton pregnancies and preterm labor with intact membranes (22-36 weeks) were randomly allocated to receive either antibiotics or placebo, plus adjunctive parenteral tocolysis, and 173 patients (antibiotics group n = 83 vs. placebo group n = 90) completed the treatment. The overall prevalence of microbial invasion of the amniotic cavity was 5.2% (9/173). No significant difference between both groups was found in maternal outcomes, including duration of randomization-to-delivery interval, frequency of preterm delivery, and frequency of clinical chorioamnionitis and endometritis. Rate of cesarean section was significantly higher in the placebo group (28% vs. 12%). Regarding neonatal outcome, no significant difference was detected between both groups in neonatal death, respiratory distress syndrome, proven sepsis, and birthweight. Suspected sepsis was significantly more frequent in the placebo group (6/90 vs. 0/78). The results of this trial indicate that amoxicillin and erythromycin do not prolong pregnancy in patients with preterm labor and intact membranes. A significant reduction in the rate of cesarean section was observed in patients receiving antibiotics. A significant reduction in the rate of neonatal suspected sepsis was also demonstrated.

Interferon induces up-regulation of Spi-1/PU.1 in human leukemia K562 cells

The human K562 cell line is derived from a chronic myelogenous leukemia in blastic crisis. Treatment of K562 cells with interferons alpha, beta or gamma resulted in inhibition of cell proliferation. Spi-1/PU.1 is a transcription factor of the Ets family which is required for normal hematopoyesis. We have found that spi-1 mRNA and protein as well as Spi-1-DNA binding activity increase after exposure of K562 cells to interferons. The increase in spi-1 expression ranged from 4- to 8-fold with the different interferons. K562 cells can be differentiated in vitro towards erythroid cells or monocyte-macrophage cells. Interestingly, the regulation of spi-1 by interferon-alpha depended on the differentiated phenotype of K562 cells: interferon-alpha failed to induce spi-1 in erythroid differentiated cells, whereas it induced spi-1 in monocyte-macrophage differentiated cells. The results suggest a role for Spi-1 in the cytostatic response to interferons.

Inhibition of the degranulation and myeloperoxidase activity of human polymorphonuclear neutrophils by Brucella melitensis

The degranulation and myeloperoxidase-H2O2-halide activities of human polymorphonuclear leukocytes from healthy donors were tested after co-incubation with either Brucella melitensis 16M, Staphylococcus aureus or Staphylococcus aureus in presence of lipopolysaccharide, protein fraction, native hapten and soluble fractions released at 65 degrees C from smooth strain of Brucella melitensis 16M. The degranulation and myeloperoxidase activities of polymorphonuclear leukocytes were significantly higher when co-incubated with Staphylococcus aureus than with Brucella melitensis. The presence of lipopolysaccharide, protein fraction, and native hapten did not cause significant modification of either degranulation or myeloperoxidase activities of polymorphonuclear leukocytes against Staphylococcus aureus. Soluble fraction released at 65 degrees C produced a significant reduction in the myeloperoxidase activity but did not alter the degranulation of polymorphonuclear leukocytes triggered by Staphylococcus aureus.

Seasonal cycles in testicular activity in the frog, Rana perezi

Studies of seasonal testicular cycle based on spermatogenetic activity and direct measurement of plasma testosterone were made in male frog Rana perezi obtained from its natural biotope in the Iberian Peninsula. Testosterone plasma level was determined by radioimmunoassay and exhibited notable differences according to season: plasma testosterone was lowest (less than 0.5 ng/ml) in summer and then increased progressively to reach a peak in spring (3-4 ng/ml), coincident with mating. After spermiation, when an increase in temperature and photoperiod in the natural habitat occurs, levels decline. Fat bodies also show a pronounced seasonal cycle with total regression following breeding and maximal development in winter. However, testicular weight was independent of seasons, and no significant change was observed throughout the year. Histological evidence indicates that although cell nests of different types are present every month of the year, the most important spermatogenetic activity is initiated in summer. The possible relationship between spermatogenetic activity and testosterone production and the importance of environmental factors as synchronizers of seasonal reproduction are discussed.

Effects of daily melatonin injections on the photoperiodic gonadal response of the female frog Rana ridibunda

The effects of daily melatonin injections on female gonads in Rana ridibunda were examined. Melatonin-treated R. ridibunda maintained on a long photoperiod (18L:6D) had significantly smaller gonads than control animals. Thus, frogs injected daily with melatonin exhibited a substantial decrease in ovary weight when compared to saline-injected animals. Our findings suggest that melatonin exerts antigonadal effects in female Rana ridibunda.

Physiological and biochemical properties and population studies in the M lactate dehydrogenase polymorphism of Discoglossus pictus (Amphibia, Anura)

1. M LDH polymorphism has been previously described in Discoglossus pictus. 2. Gene frequency at the LdM locus varied significantly in two isolated areas which differed markedly in water oxygen tension. 3. Sex distribution, relative activity of the LDH isozymes, percentage of total H and M subunits and enzyme kinetics did not differ among the distinct LDH phenotypes. 4. Under decreasing oxygen conditions, mean time to death, LT50 and oxygen consumption were similar in tadpoles of the three LDH phenotypes (fast, intermediate and slow). 5. Our results are compatible with a neutral role for this LDH polymorphism.