Eficacia de la radioterapia postoperatoria en los carcinomas epidermoides de cabeza y cuello: resultados de un ensayo prospectivo aleatorizado

INTRODUCTION

A prospective randomised clinical trial was designed to assess the usefulness of postoperative radiotherapy (RT) in terms of loco-regional control and survival in patients with surgically treated advanced (stages III to IV) head and neck squamous cell carcinoma with negative margins and without extracapsular extension in positive neck nodes.

MATERIALS AND METHODS

Between 1994 and 1995, 51 patients were included in the study and 42 were considered evaluables (from which 21 received postoperative RT). A minimum follow-up of 3 years was required.

RESULTS

The loco-regional recurrence rates were identical in irradiated and non-irradiated patients (15/21 cases--70%--in each group), as was the 5-year disease-specific survival (35% for both groups). The only parameter that was associated with a reduced disease-specific survival was the presence of regional lymph node metastases.

CONCLUSION

Our results suggest that postoperative RT does not increase loco-regional control or survival in patients with completely resected advanced head and neck squamous cell carcinoma.

Diabetic ketoacidosis associated with Metabolife: a report of two cases

AIM

To describe two cases of diabetic ketoacidosis in newly diagnosed type 1- and type-2-diabetic individuals associated with Metabolife-356.

METHODS

We report the acute hospitalizations and clinical courses of two individuals with diabetic ketoacidosis taking Metabolife-356.

RESULTS

Both patients presented without a previous diagnosis of diabetes mellitus. One patient clinically has type 1 diabetes (positive islet cell antibodies and subnormal pancreatic beta cell function to glucagon stimulation) and is treated with insulin. The second patient, after 5 days of treatment with intravenous insulin of up to 25 units per hour, is now treated with oral medications. Several possible mechanisms may exist, including the increases in catecholamines and in blood glucose after ingestion of the ingredients of these supplements. Recent clinical trial data shows an increase in blood glucose (in non-diabetics) with these supplements despite significant weight loss at 8 weeks, although no association with diabetes mellitus has been shown in these closely monitored studies.

CONCLUSIONS

Although no precipitating factor of diabetic ketoacidosis was found in these individuals, the dietary supplement Metabolife cannot be established as a precipitant. However, patients with diabetes should take this supplement only after consultation with their health care provider, as stated on the product label. Most individuals using this supplement meet the current criteria for screening to detect undiagnosed diabetes mellitus and should consider these tests.

Genotypes and S-gene variability of Mexican hepatitis B virus strains

The genotypes and subtypes of 15 Mexican hepatitis B virus strains were determined by sequencing and phylogenetic analysis of the small S-gene. The most predominant strains were found to be divergent genotype/subtype F/adw4 strains (66.6%), followed by A/adw2 (20.0%), D/ayw3 (6.7%), and G/adw2 (6.7%). The S-genes of the Mexican genotype F strains and two Nicaraguan strains described previously formed a subcluster with more than 4% divergence from the other strains within this genotype. The Mexican strains within genotypes A and D showed the highest homology with strains from Europe and the United States. Ten amino acid substitutions not described previously were found in the S-genes of strains from nine chronic carriers, whereas the S gene in strains from six acute hepatitis B patients were highly conserved as compared to their respective genotypes. One genotype F strain from an HBsAg positive chronic carrier had a T to A mutation at position 647, forming a translational stop at codon 216. Two genotype F strains from HBsAg negative chronic carriers had a Val180 instead of an Ala found in the other genotype F strains. This study shows that a divergent genotype F predominates in Mexican strains analyzed, which presented amino acid substitutions not reported previously outside the a determinant.

Seasonal patterns of arthropods occurring on sheltered and unsheltered pig carcasses in Buenos Aires Province (Argentina)

Differences in the succession of insects and other Arthropoda (invertebrate animals with jointed legs), on domestic pig carcasses placed under a roof and under the open sky have been studied in Buenos Aires Province, Argentina (latitude 34 degrees 45'S) in all the seasons of the year. Faunal associations proved different for each treatment in winter: the common bluebottle Calliphora vicina was found in both, but on the sheltered carcass Cochliomyia macellaria and the rare Phaenicia cluvia were found as well. In the fall, the difference between sheltered and unsheltered carcasses was small (six species on the former and five species on the latter); in spring and summer, the difference was negligible.

P53 allelic loss and outcome in patients with squamous cell carcinoma of the head and neck

Although loss of heterozygosity (LOH) on the p53 locus is frequent in squamous cell carcinomas of the head and neck (SCCHN), controversy still remains regarding the prognostic significance of such an event. Eighty consecutive SCCHN were studied. DNA was extracted from matched sets of normal and tumour tissue and used for polymerase chain reaction amplification of microsatellite markers located in the p53 locus. LOH at the p53 locus was found in 39 (70%) of the 56 informative cases. No relationship was found between p53 LOH and age, site, T stage, N stage, disease stage, and histological differentiation. Recurrence occurred in 53% of the cases with LOH and in 58% of the cases without it (P = 0.28). Moreover, no statistically significant association was found between p53 LOH and disease-specific survival (log-rank P = 0.98). These data suggest that although LOH at the p53 locus is common in SCCHN, this finding is of little clinical significance.

[The role of mitral valve balloon valvuloplasty in the treatment of rheumatic mitral valve stenosis during pregnancy]

OBJECTIVE

To analyze the immediate results and the clinical evolution of a group of fertile age women with rheumatic mitral stenosis, in whom percutaneous balloon mitral valvuloplasty was performed before or during pregnancy.

PATIENTS AND METHOD

Eighty-one women with mitral stenosis, submitted to balloon mitral vavuloplasty, were studied. They were divided into three groups, according to their desire of no further pregnancies (group A; n = 19), pregnancy during the follow-up (group B; n = 23) or valvuloplasty was performed during pregnancy (group C; n = 39). Patients from group B and C were controlled during pregnancy, childbirth and puerperium, and the newborns of women in group C were followed from birth to the age of 5 years.

RESULTS

Mortality in the three groups was null and the incidence of miscarriage was 2 (8.6%) in group B and 3 (9.1%) in group C. Normal delivery was predominant in group B and delivery by caesarean was predominant in group B. Success was immediate in all the cases. The procedure was repeated in 3 women due to restenosis. The media valvar area rase from 0.93 to 2.05 cm2 in group A, from 1.28 to 2.04 cm2 in group B and from 0.84 to 2.14 cm2 in group C (intergroup p = NS). The functional class improved in the three groups of patients.

CONCLUSION

Percutaneous balloon mitral valvuloplasty is an effective, efficient method for the treatment of rheumatic mitral stenosis during pregnancy, after organogenesis, or at any time in a woman's life, as long as it is indicated according to clinical and echocardiographic evaluation criteria.

Actigraphic sleep-wake patterns and urinary 6-sulfatoxymelatonin excretion in patients with Alzheimer's disease

Recent studies suggest melatonin, due to its antioxidant and free-radical-scavenging actions, may play a role in the neuroprotection against amyloid, which is implicated in the pathogenesis of Alzheimer's disease (AD). In this study, we determined urinary 6-sulfatoxymelatonin (aMT6s) excretion together with actigraphic sleep-wake patterns of untreated male patients with AD who lived at home. Results were compared with those obtained from normal age-matched elderly and normal young male subjects. Similar measurements were also performed in another group of patients with AD who were treated with a cholinesterase inhibitor (Donepezil, Aricept). Total 24h aMT6s values were significantly reduced in elderly controls (19.9h +/- 5.2 microg/ 24h), in those with untreated AD (12.7 +/- 4.4 microg/24h), and in patients treated for AD (12.4 +/- 4.4 microg/24h) compared with normal young men (32.8 +/- 3.1 microg/24h). A day-night difference in aMT6s was evident in all young controls, in 50% of elderly controls, in only 20% of patients with untreated AD, and in 67% of those with AD receiving Aricept. Sleep quality (expressed as sleep efficiency, wake time, and long undisturbed sleep duration) was better in young and elderly controls compared with the two groups of patients with AD. There was no significant correlation between aMT6s values or sleep patterns and the severity of cognitive impairment in patients with AD. Taken together, these data suggest that disrupted sleep, decreased melatonin production, and partial lack of day-night difference in melatonin secretion were observed equally in normal elderly and in patients with AD. Our results do not permit drawing any conclusion as to whether changes in urinary aMT6s excretion is correlated with disturbed sleep in patients with AD.

Xanthine oxidase released from reperfused hind limbs mediate kupffer cell activation, neutrophil sequestration, and hepatic oxidative stress in rats subjected to tourniquet shock

We have shown previously that rats subjected to tourniquet shock develop an acute form of remote organ injury of the liver that is both Kupffer cell (KC) and polymorphonuclear (PMN) leukocyte dependent. Circulating plasma xanthine oxidase (XO) has been shown to be responsible for the development of endothelial dysfunction and for remote organ injury of the lung and intestine after ischemia-reperfusion protocols. We now hypothesize that XO is released from rat hind limbs upon reperfusion and that it is responsible for KC and PMN leukocyte activation in this shock model. Our results show that about 30% of rat gastrocnemius muscle xanthine dehydrogenase (XD) is converted to XO during the 5-h tourniquet period and that it is released into the femoral vein within 10 min of reperfusion. Total muscle xanthine oxidoreductase activity (XO + XD) decreases within 30 min of reperfusion and is paralleled by a corresponding increase in femoral vein lactic dehydrogenase. In addition, liver tissue XO increases significantly within 30 min of reperfusion without a corresponding conversion of endogenous XD. Conversion of hepatic XD becomes evident 60 min after reperfusion is initiated, as does XO, and alanine aminotransferase (ALT) release into the hepatic vein, presumably from damaged hepatocytes as a consequence of oxidative stress. Tissue myeloperoxidase activity also increases significantly after the 60-min reperfusion period. That XO mediates KC and PMN activation is supported by the following observations: a) the close relationships between plasma XO and the time courses of tumor necrosis factor-alpha TNFalpha release into the hepatic vein and colloidal carbon clearance by KCs; b) that colloidal carbon clearance, TNFalpha and ALT release, loss of tissue free thiols, lipid peroxidation (TBARS), and liver infiltration by PMN neutrophils can also be induced by the administration of exogenous XO to normal rats; and c) pretreatment of rats with allopurinol inhibits KC activation and liver leukocyte infiltration. These results suggest that XO, released from the ischemic limb on reperfusion, is taken up by the liver were it mediates KC and PMN neutrophil activation and thus contributes to the development of multiple system organ failure after hind limb reperfusion.

Induction of autoimmunity in a transgenic model of B cell receptor peripheral tolerance: changes in coreceptors and B cell receptor-induced tyrosine-phosphoproteins

Abrogation of peripheral tolerance in transgenic mice that express a uniform B-cell receptor may create a powerful tool to examine the molecular mechanisms that underlie the autoimmune response in B cells. Here we report that processes that induce a systemic lupus erythematosus-like syndrome in normal mice, namely chronic graft vs host reaction, trigger systemic autoimmunity in a well-established transgenic mice model of B cell receptor peripheral tolerance. The induction of graft vs host reaction in mice that carry both a rearranged B cell Ag receptors specific for hen egg lysozyme and expressing chronically circulating hen egg lysozyme Ag resulted in induction of high and sustained levels of circulating anti-hen egg lysozyme autoantibodies and glomerulonephritis with proteinuria. This was associated with marked changes in expression of cell-surface proteins, such as CD23 and complement receptor 2. B cells from the graft vs host-induced mice could proliferate in vitro in response to self-Ag, and upon stimulation with anti-IgD demonstrated rapid phosphotyrosine phosphorylation of specific proteins, which could not be induced in the anergic double transgenic B cells. Conversely, loss of tolerance was not associated with a higher induction in the level of Syk kinase phosphorylation following stimulation with anti-IgD. Taken collectively, these data establish that 1) processes that induce a systemic lupus erythematosus-like syndrome in normal mice can abrogate peripheral tolerance in transgenic mice expressing self-tolerized B cells, and that 2) loss of tolerance in this model is associated with marked changes in surface expression of B cell coreceptors as well as with selective changes in IgD-induced signaling by discrete tyrosine-phosphoproteins, but not Syk kinase.

The multicomponent automated dissolution system: an alternative in the development and pharmaceutical analysis of generic polydrugs

The necessity of assuring the quality of polydrugs, especially those with low aqueous solubility and in vivo absorption, has led to the development and evaluation of new techniques that can reduce the time and cost of analysis. This study examines the efficiency and accuracy of an automated dissolution system, fitted with an integrated multicomponent detector, for analysis of generic polydrugs using multiple linear regression (MLR). Trimethoprim and sulphamethoxazole were chosen as model drugs for this study and comparison was made with a conventional analysis based on HPLC. Both analytical systems under study gave reproducible and accurate results. Analysis of variance showed that there was no significant statistical difference between the methods of analysis, nor any statistical difference between the measured amounts of drug in the three different formulations. We have demonstrated that low cost instrumentation coupled with MLR data processing provides entirely satisfactory drug analysis to standard at least as good as that achieved using HPLC and provides an opportunity to reduce the time and analysis cost of other generic formulations.

Percutaneous mitral valvotomy in patients eighteen years old and younger. Immediate and late results

OBJECTIVE - To analyze immediate and late results of percutaneous mitral valvotomy (PMV) in patients < or = 18 year. METHODS - Between August '87 and July '97, 48 procedures were performed on 40 patients. The mean age was 15.6 years; 68.7% were females four of whom were pregnant. RESULTS - Success was obtained in 91.7% of the procedures. Immediate complications were severe mitral regurgitation (6.3%) and cardiac tamponade (2.0%). Late follow-up was obtained in 88.8% of the patients (mean value=43.2+/-33.9 months). NYHA functional class (FC) I or II was observed in 96.2% of the patients and restenosis developed in five patients, at a mean follow-up of 29.7+/-11.9 months. Three patients presented with severe mitral insufficiency and underwent surgery. Two patients died. CONCLUSION - PMV represents a valid therapeutic option in young patients. In these patients, maybe because of subclinical rheumatic activity, restenosis may have a higher incidence and occur at an earlier stage than in others persons.