Hybrid tumours of the salivary glands. A report of two cases involving the palate and a review of the literature

Hybrid tumours are very rare salivary gland lesions composed of two or more different tumoural entities in a single neoplasm that arise within a definite topographical region. In most cases adenoid cystic carcinoma has been the predominant component in these lesions. In this study we describe two patients with hybrid tumours located in the palate, one in a 49-year-old woman and one in a 71-year-old man. The first case involved adenoid cystic carcinoma and mucoepidermoid carcinoma, and the patient in the second case exhibited adenoid cystic carcinoma and epithelial-myoepithelial carcinoma. Both patients were treated with surgery and radiotherapy, and there has been no evidence of recurrence after 13 and 36 months of follow-up, respectively. The recognition of the histologic component with the higher grade of malignancy in every case of hybrid tumour of the salivary glands is a necessary step to determine the biological behaviour and, consequently, to determine the proper therapeutic approach.     

Reduced tumor growth in vivo and increased c-Abl activity in PC3 prostate cancer cells overexpressing the Shb adapter protein

Background  

Induction of apoptosis is one strategy for treatment of prostate cancer. The Shb adapter protein has been found to regulate apoptosis in various cell types and consequently human prostate cancer 3 (PC3) cells were transfected to obtain cells overexpressing Shb in order to increase our understanding of the mechanisms regulating PC3 cell apoptosis.     

Assay of cytomegalovirus susceptibility to ganciclovir in renal and heart transplant recipients

Ganciclovir (GCV) prophylaxis or pre-emptive therapy significantly reduce the rate of cytomegalovirus (CMV) disease and viremia, but increase the potential for emergence of ganciclovir-resistant CMV strains. The inhibitor concentration at 50% (IC(50)) of GCV from 156 CMV isolates from 59 renal or heart transplant recipients was calculated by means of a rapid phenotypic susceptibility assay. Twenty-seven strains were from 14 patients undergoing GCV therapy. The IC(50) was higher in patients under the prophylaxis regimen. One CMV strain, from a heart transplant recipient, became GCV-resistant after 1 month of therapy (IC(50)=13.7 micromol/l). These data, together with clinical and virological markers, suggested that a switch to foscarnet was necessary, and good evolution was observed. Thus, assay of CMV susceptibility to GCV could be helpful in clinical management.     

Evolutionary aspects of “chloroplast-like” trnN and trnH expression in higher-plant mitochondria

Two identical “chloroplast-like” tRNA^Asn genes, trnN1 and trnN2, have been identified in the potato (Solanum tuberosum) mitochondrial genome. The flanking sequences of trnN1 are unrelated to the corresponding authentic potato chloroplast regions, whilst those of trnN2 are very similar to the chloroplast sequences. The trnN1 copy is present in the mitochondrial genome of various plants whereas the second copy, trnN2, is absent from all the other plant genomes studied so far. Interestingly, both trnN copies are expressed in potato mitochondria. Sequences flanking the chloroplast-like tRNA^His gene (trnH), present as a single copy in the potato mitochondrial DNA, are unrelated to the corresponding chloroplast sequences, whereas chloroplast-derived sequences have been maintained in the vicinity of the maize chloroplast-like mitochondrial trnH gene. However, both the potato and the maize trnH are expressed in mitochondria. Received: 10 April / 1 August 1997     

General Practitioners in Public Obstetrics - an Underutilized Resource

Summary: We questioned 229 general practitioners (GPs), 288 women who had recently delivered babies in public hospitals, 26 public hospital doctors, and 33 midwives in South Brisbane. Shared antenatal care was undertaken by 84% of mothers, and recently provided by 88% GPs. Mothers valued having sufficient time with their antenatal clinician, continuity of care, and short waiting and travel times. They preferred a GP to provide antenatal care, and a hospital midwife to deliver them. GPs were interested in providing even more obstetric care - one third in providing intrapartum care - and in gaining continuing education in obstetrics. Hospital doctors and midwives were supportive of women choosing the personnel to deliver them, and of an increased GP and midwife role in public hospital obstetrics, but unenthusiastic about home deliveries. There is widespread support for an increased role for GPs in public obstetrics.     

Attenuation of insulin-induced drinking by beta-adrenoceptor antagonists.

Insulin-induced drinking (IID) in male Wistar rats, evoked by administering 5 U/kg of crystalline porcine insulin i.p., was significantly decreased by propranolol (0.1 and 0.5 mg/kg s.c.) after 1 and 2 h. The blood glucose of rats treated with a much higher dose of propranolol (10 mg/kg body weight) and insulin did not differ from that of rats treated solely with insulin after 30 and 120 min. Atenolol (0.5 mg/kg s.c.) caused a reduction in IID after 1 and 2h. Butoxamine (1 mg/kg s.c.) also reduced IID after 1 and 2h, and at 0.5 mg/kg after 1h. The alpha-blocker, phenoxybenzamine (10 mg/kg s.c.), had the opposite effect, stimulating IID after 2h. There is no direct evidence that insulin activated the sympathetic system at the doses used in these experiments. Nevertheless, the results reported here seem to be compatible with the involvement of the sympathetic system in IID, possible through the renin-angiotensin system.     

Structure-activity relationship in the gastric cytoprotective effect of several sesquiterpene lactones.

The structural requirements for the gastric cytoprotective activity of several sesquiterpene lactones are reported. A theoretical-experimental study on the potentially active centers is carried out. The biological evaluation of reduced analogues and the simulation of the molecular interactions between these compounds and an endogenous cysteine residue suggest that the presence of a non sterically hindered Michael acceptor seems to be an essential structural requirement for the cytoprotective activity in this family of compounds. This observation suggests that cytoprotection is mediated through a Michael reaction between the sulfhydryl-containing peptides of the mucosa and Michael acceptors present in the molecules under study. This mechanism of action is in addition to and distinct from the one proposed in our previous paper, namely, that these sesquiterpenes stimulate endogenous synthesis of prostaglandins.     

Electrocardiographic findings in pulmonary arterial hypertension in children

Pulmonary hypertension (PH) induces high risk of cardiovascular morbidity and mortality, mainly in the primary or essential type. Invasive studies are needed to confirm the diagnosis; among the non- invasive approach, the electrocardiogram has been used to suspect such entity with poor results due to inadequate diagnostic criteria. Twelve children with pulmonary hypertension of the essential type (PPH) and ten children with PH due to interventricular septal defect (VSD) were studied haemodynamically and electrocardiographically and compared to electrocardiographic data of 53 normal children. PPH showed higher resistances than VSD (17.2 +/- 1.9 vs 6 +/- 0.6 u/m2 p less than 0.01) with the same pressure level (99.5 +/- 10.3 vs 101.5 +/- 4.8 mmHg). Right axis deviation, peaked P wave, increased ventricular activation time and prominent ST-T changes were seen in PPH patients whereas in VSD the electrical axis was within normal limits, without P wave changes and in some cases, less conspicuous ST-T abnormalities were observed (p less than 0.01). Such changes showed good sensitivity (80%) and specificity (81%) to suspect PH with resistances higher than 10 u/m2 with a predictive value of 75% (p less than 0.02). P wave and ST-T changes could be of use to suspect PPH with elevated resistances instead of right ventricular hypertrophy voltage criteria.     

Involvement of IL-1beta in acute stress-induced worsening of cerebral ischaemia in rats.

Stress is known to be one of the risk factors of stroke. Most of the knowledge on the effects of stress on cerebrovascular disease in humans is restricted to catecholamines and glucocorticoids effects on blood pressure and/or development of atherosclerosis. However, few experimental studies have examined the possible mechanisms by which stress may affect stroke outcome. We have used an acute stress protocol consisting of the exposure of male Fischer rats to an acute, single exposure immobilisation protocol (6 h) prior to permanent middle cerebral artery occlusion (MCAO), and we have found that stress worsens behavioural and neurological outcomes and increased infarct size after MCAO. The possible regulatory role of the TNFalpha and IL-1beta was studied by looking at the release of these cytokines in brain. The results of the present study showed an increase in IL-1beta release in cerebral cortex after exposure to acute stress. Brain levels of IL-1beta are also higher in previously stressed MCAO rats than in MCAO animals without stress. Pharmacological blockade of IL-1beta with an antibody anti-IL-1beta led to a decrease in the infarct size as well as in neurological and behavioural deficits after MCAO. In summary, our results indicate that IL-1beta, but not TNFalpha, accounts at least partly for the worsening of MCAO consequences in brain of rats exposed to acute stress.