Resistance to chemically-induced mammary tumors in Copenhagen X nude- derived F2 athymic rats: evidence that T-cell immunity is not involved in Copenhagen resistance

Resistance to chemically-induced mammary tumors in the Copenhagen rat is well defined, but the mechanism of resistance has yet to be determined. We have tested whether or not Copenhagen rat resistance is dependent on T-cells, since several lines of evidence supported an involvement of the immune system. We crossed Copenhagen rats with an athymic nude rat to produce F1s, that were interbred to produce F2 animals, some of which were athymic with partial Copenhagen rat background. A comparison of the mammary tumor incidences between the nude athymic F2 animals and their non-nude littermates allowed us to determine what role, if any, T-cells played in resistance. Following treatment with N-methyl-N-nitrosourea, we observed no difference in the tumor incidences between the two groups. Furthermore, the mammary tumor incidences in the F2 nude and non-nude animals was almost zero. These results indicate that T-cells are not involved in Cop resistance, and that nude rats are resistant to N-methyl-N-nitrosourea-induced mammary tumorigenesis.      

Value of chest radiography in excluding traumatic aortic rupture

A retrospective review of chest radiographs from 205 patients with blunt chest trauma who also underwent aortography was performed. Forty-one of the 205 had aortographically proved aortic rupture. Discriminant analysis of 16 radiographic signs indicated that the most discriminating signs were loss of the aorticopulmonary window, abnormality of the aortic arch, rightward tracheal shift, and widening of the left paraspinal line without associated fracture. No single or combination of radiographic signs demonstrated sufficient sensitivity to indicate all cases of traumatic aortic rupture on plain chest radiographs without the performance of a large number of aortographically negative studies. The bedside anteroposterior "erect" view of the chest proved far more valuable than the supine view in detecting true-negative studies. Despite significant reader variability in the interpretation of the various radiographic signs, in general the analysis confirmed the role of chest radiography in this clinical situation, but suggests that its most beneficial use is in excluding the diagnosis and eliminating unwarranted aortography rather than in predicting aortic rupture.     

Balloon dilatation of excised aortic coarctations

Seven children 1-6 years of age underwent aortic resection and re-anastomosis for coarctation of the thoracic aorta. The excised segments were 1-2 cm long and were dilated in vitro with a Grüntzig balloon catheter less than two hours after resection. A pressure of 4-8 atmospheres was used, and the inflated diameter of the balloon was twice the luminal diameter of the undilated coarctation. The diameter of each specimen was increased by an average of 85%, largely because of an increase in the external diameter of the coarctation. However, extremely high pressures were required for successful dilatation, producing transmedial tears in the "normal" aorta distal to the coarctation in three specimens. These results indicate that although balloon dilatation appears feasible as palliation for aortic coarctation, further studies of its safety are necessary before instituting clinical trials.     

Designing criteria to handle diabetes patients as a strategy for quality assurance

This study was carried out at the General Hospital of Zone N masculine 14 of the IMSS in Jalisco, Mexico, with the goal of designing standardized criteria to handle hospitalized diabetes patients, as a strategy for quality assurance, through the participation of a panel of experts in internal medicine from the hospital. Participation by the attending physician in designing criteria generates a sense of belonging in the staff and makes adherence and application easier. The suggested criteria are subject to further improvement and are not intended for universal application, but to the extent that they have been useful in patient care they have far surpassed the authors' expectations when the goals of this research were originally established.     

Altered expression of transforming growth factor betas during urethral and bulbourethral gland tumor progression in transgenic mice carrying the androgen-responsive C3(1) 5' flanking region fused to SV40 large T antigen

We demonstrate that targeted expression of SV40 large T antigen (TAg) to the urethral (periurethral) and bulbourethral gland epithelium leads to adenocarcinoma formation in these tissues after 7 months of age, which are extremely rare sites for spontaneous tumor formation in humans. The development of proliferative lesions in the urethral gland predictably follows a temporal course of progression with approximately one third of male animals developing urethral tumors by 1 year of age. Tumor progression in these organs correlates to the level of TAg and p53 expression. Immunoprecipitation confirmed that SV40 TAg protein was bound to p53 and Rb p110 in vivo. Expression of transforming growth factor beta (TGFbetas) was evaluated during tumor progression of urethral gland carcinomas. Elevations of intracellular and extracellular TGFbeta1 and extracellular TGFbeta3 were found in preneoplastic and neoplastic lesions, suggesting that increased TGFbetas may augment tumor growth. c-Met expression showed a tendency for increased expression in the urethral gland carcinomas. We speculate that the directed expression of SV40 TAg by the hormone responsive C3(1) gene and subsequent tumor formation in these organs is influenced by androgens, since these tissues and carcinomas express androgen receptor (AR) and arise only in male transgenic mice. Several cell lines established from the urethral carcinomas were also shown to express AR, but are not androgen dependent in culture. To our knowledge, this is the first transgenic animal model for urethral and bulbourethral carcinomas. This transgenic mouse model and the cell lines derived from it may provide a unique opportunity for dissecting molecular mechanisms involved in the tumorigenesis of these organs which otherwise rarely develop cancer.      

Mycoplasma pneumoniae infection and neurological disease

The cases are reported of 13 children seen over a 22 month period who presented with a variety of acute neurological illnesses associated with Mycoplasma pneumoniae infection. Although presentation with a decreased level of consciousness or seizures was common, psychosis, hemiparesis, cranial nerve palsies, and Guillain-Barré syndrome were also seen. In contrast with published reports, only one child had an associated chest infection. Although some children have been left with residual disability, most have made a complete recovery. In this recent experience, M pneumoniae is a not rare cause of neurological illness in childhood and may present in unusual ways.     

Nitric oxide treatment for fulminant pulmonary hypertension

A 3 year old child with known pulmonary haemosiderosis suffered acute circulatory collapse secondary to raised pulmonary vascular resistance. Nitric oxide inhalation produced a profound improvement in circulatory parameters and gaseous exchange. Nitric oxide may have a therapeutic role in acute pulmonary hypertensive crisis.     

The effect of temperature reduction on respiratory rate in febrile illnesses

A raised respiratory rate is a useful sign in the diagnosis of pneumonia in children. It was observed that children with malaria and other febrile illnesses may also present with a raised respiratory rate. To determine the extent to which increased body temperature contributes to the raised respiratory rate observed in these children the effect of change in body temperature on respiratory rate was measured in 186 sick Gambian children with a raised respiratory rate, including those with pneumonia or malaria. A temperature dependent effect on respiratory rate of 3.7 breaths per minute per degree centigrade was demonstrated for the whole study cohort, with no significant difference between children with pneumonia or malaria. Twenty three per cent of children with pneumonia whose temperature fell had a final respiratory rate below that currently recommended by the World Health Organisation for the diagnosis of pneumonia. It is concluded that respiratory rate is to some extent dependent on body temperature in children with febrile illnesses such as pneumonia and malaria, but that this does not alone account for the raised respiratory rate seen in these children. The effect of reduction in body temperature on respiratory rate does not help to distinguish children with pneumonia from those with malaria. A history of recent use of an antipyretic or other measures to control fever is important when evaluating children for possible pneumonia.     

TREATMENT GOALS IN IRRITABLE BOWEL SYNDROME

Irritable bowel syndrome (IBS) carries a considerable economic and social impact which may, in part, be due to inefficient diagnosis and inappropriate treatment choice leading to continued patient ill health and absenteeism. Even assuming that IBS can be diagnosed positively, using well-established symptom-based criteria, management difficulties remain. Thus, pharmacological treatment choice is still based on the single predominant symptom, and many currently available treatments are ineffective in the long term. A greater understanding of the pathophysiology of IBS may lead to the development of more effective treatments that can target the multiple symptoms present in IBS. A new understanding of the role of serotonin (5-HT) and specific receptors (5-HT₃ and 5-HT₄) found in the gastrointestinal (GI) tract has led to the development of serotonergic agents which have potential clinical benefits. Recent clinical trials suggest that 5-HT4 receptor partial agonists, in particular, may have the ability to offer multiple symptom relief, without the risk of significant adverse reactions.