Support for decision-making on sharing health data for research: are data counsellors relevant?

Background

The implications of sharing one's health data are far-reaching. Potential applications of health data range from the delivery of treatments tailored to individuals' characteristics to improvements in public health, while also posing concerns about privacy, social justice and equity. Making informed decisions about health data sharing thus requires thorough consideration of the scientific, ethical and personal implications of donations. This study assessed participants' preferences regarding decision-making about health data sharing for research, including the need for support by data counsellors.

Methods

This observational cross-sectional study includes 159 patients and 479 carers followed at two reference centres for rare diseases in a Portuguese academic hospital, between June 2019 and March 2020. Participants were asked about preferred modes of decision-making: deciding on their own, deciding with support from another person, or delegating the decision to someone else. Those who responded the last two options also reported who they would choose for support or delegation: family or friends; a data counsellor; a professional with no specific training on data counselling; other. Data were analysed using descriptive and inferential statistics.

Results

The majority of respondents would prefer to decide with support (62%), 37% would prefer to decide on their own and 1% would opt to delegate the decision of sharing health data. Among those who expressed a preference for support, 60% would like to rely on a data counsellor. Carers, older and higher educated participants, and those with upper white-collar occupations and who were satisfied with their own health were significantly more likely to select data counsellors as their preferred source of support when engaging in decision-making about health data sharing for research (p < 0.05).

Conclusions

This study supports recommendations for the creation of a new professional specialty of health data counsellors.

Key messages

Most participants express the need for support in making decisions about health data sharing for research, with 60% preferring support from a data counsellor. As a new professional specialism, health data counselling can help to advance informed public participation in health research.

Congenital pulmonary lymphangiectasia and chylothorax - a case series

Congenital pulmonary lymphangiectasia (CPL) and chylothorax (CC) are rare lymphatic developmental disorders. We report six clinical cases of CPL and CC that were admitted to our level III neonatal intensive care unit over the last 20 years. One case of unilateral CC was successfully treated with pleuro-amniotic shunt; three cases of bilateral CC were associated to lung hypoplasia, hydrops fetalis, and generalized lymphangiectasias; one case of CPL was associated with obstructive congenital heart defect; one case of unilateral CC was successfully treated with thoracocentesis and medium-chain triglyceride diet. Mortality was high (66.6%).

Congenital diaphragmatic hernia: experience of 14 years

AIM

Over the last two decades, new therapies have emerged for the management of congenital diaphragmatic hernia (CDH). The aim of this paper was to review our experience in the management of newborns diagnosed with CDH over a 14-year period.

METHODS

Review of maternal and infant medical records, 1997-2010.

RESULTS

Eighty newborns with CDH; 21 (26%) were preterm and 28 (35%) of low birthweight (<2500 g), including 3 (4%) of very low birthweight (< 1500 g). Prenatal diagnosis was made in 53 (66%) cases. The location of the hernia was: left side 48 (90.5%); right 4 (7.5%); bilateral 1 (1%). Corrective surgery was performed in 58 (73%) patients. High frequency oscillatory ventilation was used in 10 (12.5%), inhaled nitric oxide in 18 (22.5%), sildenafil in 15 (18.7%) and extracorporeal membrane oxygenation in 1 (1%). The overall survival was 49% (N.=39). Since 2003, the overall survival raised to 64%. The survival rate of the appropriate for gestational age term newborns without other congenital/chromosomal anomaly or hydrops fetalis was 67% (24/36).

CONCLUSION

Our survival rate for congenital diaphragmatic hernia has improved over the last 14 years, associated to the use of new therapies, such as high-frequency oscillation ventilation (HFOV), inhaled nitric oxide and sildenafil.

Congenital Diaphragmatic Hernia. The Post-neonatal period. Part II

AIM

The aim of the study was to review our experience in the management of newborns with congenital diaphragmatic hernia (CDH).

METHODS

A retrospective study including all infants with CDH at the Hospital de São João, a center that does not provide ECMO support, for the period from 1997 to 2006. Since 2003, a new treatment protocol has been used.

RESULTS

There were 61 newborns (30 male/31 female) with a birth weight of 2800 g (880 - 3770), and a gestational age of 38 weeks (28 - 41); 46 (75 %) were inborn and 42 (69 %) had a prenatal diagnosis of CDH. There were 2 (3 %) chromosomal anomalies, 3 (5 %) with other congenital anomalies and 1 (2 %) with nonimmune hydrops fetalis. The diaphragmatic defect was left sided in 55 (90 %) cases. Corrective surgery was performed in 43 (70 %) patients. New therapies were used: HFOV 13 % (n = 8); inhaled nitric oxide 13 % (n = 8); and sildenafil 7 % (n = 4). We found that systemic arterial hypotension (p = 0.001), the severity of pulmonary hypertension (p = 0.001), prenatal diagnosis (p = 0.006), birth weight (p = 0.022), female gender (p = 0.029), inborn birth (p = 0.030), arterial pH < 7.35 at admission (p = 0.030), right-sided defect (p = 0.033) and pneumothorax (p = 0.033) to be predictive of mortality. The overall survival rate was 43 % (n = 26), and since 2003 this rate has improved to 61 % for term neonates without other congenital or chromosomal anomalies.

CONCLUSIONS

Our survival rate for infants with CDH has improved over the last ten years, and this improvement is associated with the use of new therapies such as HFOV, inhaled nitric oxide and sildenafil.

Congenital diaphragmatic hernia - the neonatal period (part I)

AIM

The aim of the study was to review our experience in the management of newborns with congenital diaphragmatic hernia (CDH).

METHODS

A retrospective study including all infants with CDH at the Hospital de São João, a center that does not provide ECMO support, for the period from 1997 to 2006. Since 2003, a new treatment protocol has been used.

RESULTS

There were 61 newborns (30 male/31 female) with a birth weight of 2800 g (880 - 3770), and a gestational age of 38 weeks (28 - 41); 46 (75 %) were inborn and 42 (69 %) had a prenatal diagnosis of CDH. There were 2 (3 %) chromosomal anomalies, 3 (5 %) with other congenital anomalies and 1 (2 %) with nonimmune hydrops fetalis. The diaphragmatic defect was left sided in 55 (90 %) cases. Corrective surgery was performed in 43 (70 %) patients. New therapies were used: HFOV 13 % (n = 8); inhaled nitric oxide 13 % (n = 8); and sildenafil 7 % (n = 4). We found that systemic arterial hypotension (p = 0.001), the severity of pulmonary hypertension (p = 0.001), prenatal diagnosis (p = 0.006), birth weight (p = 0.022), female gender (p = 0.029), inborn birth (p = 0.030), arterial pH < 7.35 at admission (p = 0.030), right-sided defect (p = 0.033) and pneumothorax (p = 0.033) to be predictive of mortality. The overall survival rate was 43 % (n = 26), and since 2003 this rate has improved to 61 % for term neonates without other congenital or chromosomal anomalies.

CONCLUSIONS

Our survival rate for infants with CDH has improved over the last ten years, and this improvement is associated with the use of new therapies such as HFOV, inhaled nitric oxide and sildenafil.

Mutant SOD1 alters the motor neuronal transcriptome: implications for familial ALS

Familial amyotrophic lateral sclerosis (FALS) is caused, in 20% of cases, by mutations in the Cu/Zn superoxide dismutase gene (SOD1). Although motor neuron injury occurs through a toxic gain of function, the precise mechanism(s) remains unclear. Using an established NSC34 cellular model for SOD1-associated FALS, we investigated the effects of mutant SOD1 specifically in cells modelling the vulnerable cell population, the motor neurons, without contamination from non-neuronal cells present in CNS. Using gene expression profiling, 268 transcripts were differentially expressed in the presence of mutant human G93A SOD1. Of these, 197 were decreased, demonstrating that the presence of mutant SOD1 leads to a marked degree of transcriptional repression. Amongst these were a group of antioxidant response element (ARE) genes encoding phase II detoxifying enzymes and antioxidant response proteins (so-called 'programmed cell life' genes), the expression of which is regulated by the transcription factor NRF2. We provide evidence that dysregulation of Nrf2 and the ARE, coupled with reduced pentose phosphate pathway activity and decreased generation of NADPH, represent significant and hitherto unrecognized components of the toxic gain of function of mutant SOD1. Other genes of interest significantly altered in the presence of mutant SOD1 include several previously implicated in neurodegeneration, as well as genes involved in protein degradation, the immune response, cell death/survival and the heat shock response. Preliminary studies on isolated motor neurons from SOD1-associated motor neuron disease cases suggest key genes are also differently expressed in the human disease.

The Parkinson's disease protein DJ-1 is neuroprotective due to cysteine-sulfinic acid-driven mitochondrial localization

Loss-of-function DJ-1 mutations can cause early-onset Parkinson's disease. The function of DJ-1 is unknown, but an acidic isoform accumulates after oxidative stress, leading to the suggestion that DJ-1 is protective under these conditions. We addressed whether this represents a posttranslational modification at cysteine residues by systematically mutating cysteine residues in human DJ-1. WT or C53A DJ-1 was readily oxidized in cultured cells, generating a pI 5.8 isoform, but an artificial C106A mutant was not. We observed a cysteine-sulfinic acid at C106 in crystalline DJ-1 but no modification of C53 or C46. Oxidation of DJ-1 was promoted by the crystallization procedure. In addition, oxidation-induced mitochondrial relocalization of DJ-1 and protection against cell death were abrogated in C106A but not C53A or C46A. We suggest that DJ-1 protects against neuronal death, and that this is signaled by acidification of the key cysteine residue, C106.

Parkin and alpha-synuclein: opponent actions in the pathogenesis of Parkinson's disease

Dominant mutations in the gene for alpha-synuclein, a small presynaptic protein, can cause Parkinson's disease. Although there is still substantial debate about the precise mechanisms, alpha-synuclein is toxic to vulnerable neurons, probably as a result of its tendency to aggregate. Opposing this is another gene product that, when mutated, causes a recessive form of parkinsonism, parkin. Parkin has been recently shown to protect cells against alpha-synuclein toxicity. However, the precise details of the mechanism are unclear. This review will discuss the concept that there are multiple neuronal functions that are targeted by mutant alpha-synuclein, and in many cases, there is evidence that parkin can protect cells against damage to the same systems. The authors will also discuss ways in which to test some of these ideas, by using newly identified genes such as DJ-1 that cause similar phenotypes.

L166P mutant DJ-1, causative for recessive Parkinson's disease, is degraded through the ubiquitin-proteasome system

Mutations in a gene on chromosome 1, DJ-1, have been reported recently to be associated with recessive, earlyonset Parkinson's disease. While one mutation is a large deletion that is predicted to produce an effective knockout of the gene, the second is a point mutation, L166P, whose precise effects on protein function are unclear. In the present study, we show that L166P destabilizes DJ-1 protein and promotes its degradation through the ubiquitin-proteasome system. A double mutant (K130R, L166P) was more stable than L166P, suggesting that this lysine residue contributes to stability of the protein. Subcellular localization was broadly similar for both wild type and L166P forms of the protein, indicating that the effect of the mutation is predominantly on protein stability. These observations are reminiscent of other recessive gene mutations that produce an effective loss of function. The L166P mutation has the simple effect of promoting DJ-1 degradation, thereby reducing net DJ-1 protein within the cell.

Microarray analysis reveals induction of heat shock proteins mRNAs by the torsion dystonia protein, TorsinA

An in-frame deletion (Delta E302/303) in the TorsinA gene has been demonstrated to be responsible for primary torsion dystonia, showing dominant inheritance with reduced penetrance. The Delta E302/303 torsinA mutation forms intracellular ER derived inclusions in a variety of cultured cells, which may suggest that the mutations might evoke ER stress. We used microarray analysis of human derived cell lines expressing the Delta E302/303 torsinA mutation in order to reveal alterations in gene expression in the hope of identifying genetic modifying loci or novel markers for disease pathogenesis. We identified transcriptional changes in multiple members of the heat shock protein family of genes, confirmed by reverse transcription-polymerase chain reaction, which could be indicative of ER stress. However, both wild type and mutant torsinA were affected to a similar extent, suggesting that this is not related to either disease state or the formation of ER-derived inclusions.

Co-ordinate transcriptional regulation of dopamine synthesis genes by alpha-synuclein in human neuroblastoma cell lines

Abnormal accumulation of alpha-synuclein in Lewy bodies is a neuropathological hallmark of both sporadic and familial Parkinson's disease (PD). Although mutations in alpha-synuclein have been identified in autosomal dominant PD, the mechanism by which dopaminergic cell death occurs remains unknown. We investigated transcriptional changes in neuroblastoma cell lines transfected with either normal or mutant (A30P or A53T) alpha-synuclein using microarrays, with confirmation of selected genes by quantitative RT-PCR. Gene products whose expression was found to be significantly altered included members of diverse functional groups such as stress response, transcription regulators, apoptosis-inducing molecules, transcription factors and membrane-bound proteins. We also found evidence of altered expression of dihydropteridine reductase, which indirectly regulates the synthesis of dopamine. Because of the importance of dopamine in PD, we investigated the expression of all the known genes in dopamine synthesis. We found co-ordinated downregulation of mRNA for GTP cyclohydrolase, sepiapterin reductase (SR), tyrosine hydroxylase (TH) and aromatic acid decarboxylase by wild-type but not mutant alpha-synuclein. These were confirmed at the protein level for SR and TH. Reduced expression of the orphan nuclear receptor Nurr1 was also noted, suggesting that the co-ordinate regulation of dopamine synthesis is regulated through this transcription factor.

Cardiac rhabdomyomas presenting in neonates

Rhabdomyoma is the most common cardiac neoplasm in neonates. Spontaneous regression of such tumors is common, particularly with smaller lesions, followed by resolution of symptoms. Because most of the tumoral masses regress spontaneously, treatment should primarily be symptomatic, while surgical removal is required only in life-threatening situations. Tuberous sclerosis is found in half of the patients with rhabdomyomas.

AIM

The aim of our work was to analyze the cases of rhabdomyoma with neonatal presentation in our hospital.

METHODS

A retrospective review was performed of the hospital records (cardiovascular examination, radiologic and echocardiographic findings, association with tuberous sclerosis, treatment and follow-up) of all neonates admitted, during the last 12 years, with the diagnosis of rhabdomyoma.

RESULTS

Six patients were found. All diagnoses were established during the first month of life. One third of our population had associated tuberous sclerosis. In three cases the tumors were multiple and the preferential location was the left ventricle. In only one case was surgical removal indicated because of the presence of life-threatening symptoms but the infant's parents refused consent for the procedure. All the children had regression of the tumoral masses.

CONCLUSIONS

The natural history of rhabdomyomas is one of spontaneous regression with surgical excision being recommended only in the presence of life-threatening symptoms.

Poly(A) polymerase from Escherichia coli adenylylates the 3'-hydroxyl residue of nucleosides, nucleoside 5'-phosphates and nucleoside(5')oligophospho(5')nucleosides (NpnN)

The capacity of Escherichia coli poly(A) polymerase to adenylylate the 3'-OH residue of a variety of nucleosides, nucleoside 5'-phosphates and dinucleotides of the type nucleoside(5')oligophospho(5')nucleoside is described here for the first time. Using micromolar concentrations of [alpha-32P]ATP, the following nucleosides/nucleotides were found to be substrates of the reaction: guanosine, AMP, CMP, GMP, IMP, GDP, CTP, dGTP, GTP, XTP, adenosine(5')diphospho(5')adenosine (Ap2A), adenosine (5')triphospho(5')adenosine (Ap3A), adenosine(5')tetraphospho(5')adenosine (Ap4A), adenosine(5')pentaphospho(5')adenosine (Ap5A), guanosine(5')diphospho(5') guanosine (Gp2G), guanosine(5')triphospho(5')guanosine (Gp3G), guanosine(5')tetraphospho(5')guanosine (Gp4G), and guanosine(5')pentaphospho(5')guanosine (Gp5G). The synthesized products were analysed by TLC or HPLC and characterized by their UV spectra, and by treatment with alkaline phosphatase and snake venom phosphodiesterase. The presence of 1 mM GMP inhibited competitively the polyadenylylation of tRNA. We hypothesize that the type of methods used to measure polyadenylation of RNA is the reason why this novel property of E. coli poly(A) polymerase has not been observed previously.

[Prognostic indexes derived from ventricular morphology in congenital diaphragmatic hernia induced by nitrofen]

BACKGROUND

Some indices derived from cardiac morphology have been proposed as prognostic factors in fetuses and newborns with congenital diaphragmatic hernia (CDH). These would be of interest in evaluating the risk of pulmonary hypoplasia and the need for surgery in the fetus. The aim of this study was to evaluate the heart-related indices in the nitrofen-induced CDH rat model.

METHODS

At day 9 1/2 of gestation dated pregnant female Wistar rats received 100 mg of nitrofen. Fetuses were harvested at day 21 1/2 by laparotomy. The fetuses exposed to nitrofen without CDH were defined as the control group (n = 38) while the fetuses exposed to nitrofen with CDH were defined as the CDH group (n = 30). The hearts from both groups were weighed, processed for paraffin embedding and fragmented in serial 7 microns thick transverse sections. In the hearts without cardiac morphological defects the right and the left ventricular cavity volumes were estimated. These allowed calculation of cardioventricular and left-ventricular mass indices.

RESULTS

In the fetuses without cardiac malformations, no significant difference was found regarding heart-to-body weight ratio, cardioventricular index or left ventricular mass between the study groups.

CONCLUSION

In this model the presence of CDH was not associated with any alteration in cardiac dimension, in the absence of structural malformations. These results suggest that the indices derived from ventricular morphology should not be used to evaluate the prognosis in fetuses and newborns with CDH.

A new fetal rat model of gastroschisis: development and early characterization

BACKGROUND/PURPOSE

The perinatal management and pathophysiology of gastroschisis remain controversial. Large animal experimental models of gastroschisis are inherently limited by expense and length of gestation, making multiple studies and statistical analysis difficult. To address these limitations the authors have developed a model of gastroschisis in the fetal rat.

METHODS

Twenty-one time-dated pregnant rats underwent laparotomy at 18 (1/2) day's gestational age. The exposed uterus was bathed in ritodrine for tocolysis. The right posterior leg was exteriorized through a hysterotomy, and under a dissecting microscope (16x) the fetal small bowel was exteriorized through a small incision performed on the right lower abdominal quadrant. The amniotic fluid was restored with saline solution and the hysterotomy closed with a purse-string suture. Control fetuses underwent hysterotomy and leg manipulation only. The surgical time was uniformly less than 60 minutes. Fetuses were harvested by cesarean section at 21 (1/2) days' gestational age. Fetal intestine was assessed by microscopic examination, and fetal weight, intestinal length, and intestinal weight per unit length were evaluated.

RESULTS

There was a significant surgical and anesthetic learning curve, which is not included in this report. After this, the authors achieved a maternal survival of 100% (n = 21). We created gastroschisis in 64 fetuses (58 survivors, 90.6%), and 33 fetuses were only manipulated (30 survivors, 90.9%). The number of induced gastroschisis per pregnant rat varied between 2 and 5 with median of 3. On gross examination, eviscerated intestine appeared dilated, edematous, and covered by peel when compared with control intestine. Fetuses with gastroschisis had significantly reduced body weight (4.1+/-0.5 v 5.6 g +/- 0.5 g) and intestinal length (102+/-19 v 210+/-17 mm) relative to controls, whereas the intestinal weight per unit length (1.75+/-0.29 v 0.71 +/- 0.1 mg/mm) was markedly increased (P<.001).

CONCLUSIONS

The pathophysiology observed in this experimental model appears to resemble human gastroschisis. In comparison with large animal models, the rat model offers the advantages of low expense, short gestation, littermate controls, and high maternal and fetal survival rates. In addition, there are specific probes and reagents available for application of molecular methodology to clarify the mechanisms responsible for the intestinal damage. This model appears appropriate for future experimental studies on gastroschisis.

Heterotrisomy, a significant contributing factor to ventricular septal defect associated with Down syndrome?

Down syndrome (DS; trisomy 21) is associated with a wide range of variable clinical features, one of the most common being congenital heart defects (CHD). We used molecular genetic techniques to study the inheritance of genes on chromosome 21 in children with DS and CHD. Polymorphic markers on the long arm of chromosome 21 were analysed in 99 families who had a child with DS. Of these, 60 children had a CHD and 39 children had no CHD. Heterotrisomy describes the inheritance of an allele from each of three different grandparents. In some cases heterotrisomy will involve the inheritance of three different alleles. Heterotrisomic regions were defined as those showing retention of non-disjoining parental heterozygosity at polymorphic loci in the non-disjoined chromosomes of children with DS. Using polymorphic non-coding markers, we identified a consistent 9.6-cM minimum region (D21S167-HMG14) of heterotrisomy in children with DS and ventricular septal defect (VSD). Comparing individuals with DS and VSD to all others with DS (those either with no CHD or with any other CHD combined) shows the individuals with DS and VSD to have significantly more non-reduction or heterotrisomy in this region (P=0.006, Fisher's exact test, two-tailed). We postulate that heterotrisomy for a gene or genes in this region is a contributing factor to the pathogenesis of VSD in trisomy 21 either through the presence of three different specific alleles or through the presence of specific combinations of alleles.

Heart-related indices in experimental diaphragmatic hernia

BACKGROUND

Heart-related indices have been suggested as useful tools to evaluate left ventricular (LV) hypoplasia, which might predict the outcome of fetuses and infants with congenital diaphragmatic hernia (CDH). The current study analyzed the behavior of such indices in the nitrofen-induced CDH rat model.

METHODS

Dated pregnant Wistar rats received at day 9.5 of gestation either a dose of 100 mg of nitrofen or just the vehicle. Body, lung, and heart weights were measured in 12 newborn rats not exposed to nitrofen (Ctrl group) and 68 animals exposed to nitrofen: 30 without CDH (non-CDH group) and 38 with left CDH (CDH group). Each heart was fragmented in 7-microm thick sections. Only hearts with no evidence of cardiac morphologic defects (CMD) were studied further to estimate right and left ventricular cavity volumes, septal, right, and left ventricular free wall masses. These parameters allowed the calculation of the cardio-ventricular (CVindex) and LV mass indices. The aorta-to-pulmonary artery ratio also was calculated.

RESULTS

Excluding fetuses with CMD, the heart-to-body weight ratio was reduced significantly in animals exposed to nitrofen, whereas no significant differences were observed between non-CDH versus CDH groups. Although the left and right ventricular cavity volumes were both reduced significantly in nitrofen-treated rats, they were not changed significantly by the existence of CDH, and the calculated CVindex was similar in the 3 groups. Estimated septal and LV masses were reduced markedly in the nitrofen-treated animals and further reduced by the presence of CDH. However, when LV mass was normalized (LV mass index) the difference became restricted to the animals exposed to nitrofen but was not influenced by the presence of CDH. Finally, the aorta-to-pulmonary artery ratio was similar in all studied groups.

CONCLUSIONS

The results of the current study suggest that, although nitrofen had been responsible by global heart hypoplasia, the presence of CDH was not associated with significant underdevelopment of the heart or of the LV in rat fetuses without CMD. Based on these results, we think that the evidence for prenatal counseling based on heart-related indices should be critically reconsidered.

[Patent ductus arteriosus in neonatal intensive care]

OBJECTIVE

In this study we evaluated the prevalence of symptomatic patent ductus arteriosus (PDA) in newborns, admitted to a neonatal intensive care unit (NICU), as well as the clinical features and the outcome of medical or surgical treatment.

METHODS

We carried out a retrospective medical chart review of 42 newborns admitted to an NICU between May 1996 and May 1998. Data regarding birth weight, sex, gestational age, prenatal corticotherapy and surfactant needs were gathered. Clinical evolution was assessed based on mechanical ventilation, morbidity and mortality. The therapeutic options and their results where analysed.

RESULTS

Of the 1,195 newborns admitted to an NICU, 42 had symptomatic PDA. The prevalence was higher in newborns with a low birth weight. There was no significant difference regarding the administration of steroids prenatally in the newborns with PDA compared to the remaining newborns without PDA. Surfactant therapy, mechanical ventilation, bronchopulmonary dysplasia, necrotizing enterocolitis and intraventricular hemorrhage were found to be more frequent in patients with PDA, especially among those with a lower birth weight, with statistical significance for newborns weighing less than 2,500 g (p < 0.05). The therapy most frequently used was indomethacin, with a success rate of 22/23 (95.6%) and with two cases of acute renal failure as side effects. Only one infant required surgical ligation of PDA. Mortality was similar in both groups (PDA vs. no PDA).

CONCLUSION

PDA was probably underdiagnosed in our NICU. Morbidity, but not mortality, was higher in newborns with symptomatic PDA. We conclude that treatment with indomethacin is preferred to surgical ligation as an initial approach in those infants. Our data show the importance of early screening with echocardiogram for "silent" PDA in low birth weight neonates.

[Absence of cardiac hypoplasia in an experimental model of congenital diaphragmatic hernia]

INTRODUCTION

Congenital diaphragmatic hernia (CDH) is a rare malformation in newborns. Amongst the various prenatal prognostic criteria, it is suggested that heart weight could be useful in evaluating the severity of lung hypoplasia. In this work we studied heart development in a rat model with nitrofen-induced CDH.

MATERIAL AND METHODS

Pregnant female Wistar rats were treated on day 9 1/2 of gestation with 100 mg of nitrofen dissolved in 1 ml of olive oil. The control group was only treated with 1 ml of olive oil. The foetuses were delivered by caesarean section on day 21 1/2 of gestation. The weight of the foetuses was recorded. Under microscopy, the foetuses were dissected and the diaphragm was inspected. The wet weight of the heart and lung were recorded. The results are presented as a mean +/- standard deviation. A statistical analysis was made with the one-way ANOVA test on Ranks, and the Dunn test for post-test analysis. The statistical significance was set at a p < 0.05.

RESULTS

The foetuses with CDH (n = 16) were lighter and had a smaller left lung/body weight ratio when compared with animals exposed to nitrofen without CDH (n = 18) and with controls (n = 12) (p < 0.05). The heart/ body weight ratio was smaller in foetuses exposed to nitrofen (p < 0.05), but we could not find any differences between nitrofen-treated treated foetuses with vs without CDH (n.s.).

CONCLUSIONS

In spite of the lung hypoplasia, we could not demonstrate the presence of heart hypoplasia in rats with CDH when compared to nitrofen-treated foetuses without CDH.

New strategies on molecular biology applied to microbial systematics

Systematics is the study of diversity of the organisms and their relationships comprising classification, nomenclature and identification. The term classification or taxonomy means the arrangement of the organisms in groups (rate) and the nomenclature is the attribution of correct international scientific names to organisms and identification is the inclusion of unknown strains in groups derived from classification. Therefore, classification for a stable nomenclature and a perfect identification are required previously. The beginning of the new bacterial systematics era can be remembered by the introduction and application of new taxonomic concepts and techniques, from the 50's and 60's. Important progress were achieved using numerical taxonomy and molecular taxonomy. Molecular taxonomy, brought into effect after the emergence of the Molecular Biology resources, provided knowledge that comprises systematics of bacteria, in which occurs great evolutionary interest, or where is observed the necessity of eliminating any environmental interference. When you study the composition and disposition of nucleotides in certain portions of the genetic material, you study searching their genome, much less susceptible to environmental alterations than proteins, codified based on it. In the molecular taxonomy, you can research both DNA and RNA, and the main techniques that have been used in the systematics comprise the build of restriction maps, DNA-DNA hybridization, DNA-RNA hybridization, sequencing of DNA sequencing of sub-units 16S and 23S of rRNA, RAPD, RFLP, PFGE etc. Techniques such as base sequencing, though they are extremely sensible and greatly precise, are relatively onerous and impracticable to the great majority of the bacterial taxonomy laboratories. Several specialized techniques have been applied to taxonomic studies of microorganisms. In the last years, these have included preliminary electrophoretic analysis of soluble proteins and isoenzymes, and subsequently determination of deoxyribonucleic acid base composition and assessment of base sequence homology by means of DNA-RNA hybrid experiments beside others. These various techniques, as expected, have generally indicated a lack of taxonomic information in microbial systematics. There are numberless techniques and methodologies that make bacteria identification and classification study possible, part of them described here, allowing establish different degrees of subspecific and interspecific similarity through phenetic-genetic polymorphism analysis. However, was pointed out the necessity of using more than one technique for better establish similarity degrees within microorganisms. Obtaining data resulting from application of a sole technique isolatedly may not provide significant information from Bacterial Systematics viewpoint.