A novel mutation in the endothelin B receptor gene in a patient with Shah-Waardenburg syndrome and Down syndrome.
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DNA Mutational Analysis↗
Biomedical subjects
N J Robertson
Publications and source records attributed to N J Robertson.
Developments in vapour cloud explosion blast modeling.
TNT Equivalency methods are widely used for vapour cloud explosion blast modeling. Presently, however, other types of models are available which do not have the fundamental objections TNT Equivalency models have. TNO Multi-Energy method is increasingly accepted as a more reasonable alternative to be used as a simple and practical method. Computer codes based on computational fluid dynamics (CFD) like AutoReaGas, developed by TNO and Century Dynamics, could be used also in case a more rigorous analysis is required. Application of the Multi-Energy method requires knowledge of two parameters describing the explosion: a charge size and a charge strength. During the last years, research has led to an improved determination of the charge strength (i.e., the class number or source overpressure) to be chosen to apply the blast charts. A correlation has been derived relating the charge strength to a set of parameters describing the boundary conditions of the flammable cloud and the fuel in the cloud. A simple approach may not be satisfactory in all situations. The overpressure distribution inside a vapour cloud explosion is generally not homogeneous and the presence of obstructions causes directional blast propagation in the near field. A CFD approach, in which the actual situation is modeled, supplies case-specific results. An overview of the key aspects relevant to the application of the Multi-Energy method and CFD modeling is provided. Then the application of the two methods is demonstrated for an example problem involving the calculation of the explosion blast load on a structure at some distance from the explosion in an offshore platform complex.
Air Pollution↗
Periosteal osteosarcoma of the cranium.
We report a case of periosteal osteosarcoma arising from the occiput in a 29-year-old woman. To the best of our knowledge, this is the first documented case of periosteal osteosarcoma involving the cranium.
Adult↗
Characterization of cerebral white matter damage in preterm infants using 1H and 31P magnetic resonance spectroscopy.
The biochemical characteristics of white matter damage (WMD) in preterm infants were assessed using magnetic resonance spectroscopy (MRS). The authors hypothesized that preterm infants with WMD at term had a persisting cerebral lactic alkalosis and reduced N-acetyl aspartate (NAA)/ creatine plus phosphocreatine (Cr), similar to that previously documented in term infants weeks after perinatal hypoxiaischemia (HI). Thirty infants (gestational age 27.9 +/- 3.1 weeks, birth weight 1,122 +/- 445 g) were studied at postnatal age of 9.8 +/- 4.1 weeks (corrected age 40.3 +/- 3.9 weeks). Infants were grouped according to the presence or absence of WMD on magnetic resonance (MR) images. The peak area ratios of lactate/Cr, NAA/Cr, myo-inositol/Cr, and choline (Cho)/Cr were measured from an 8-cm3 voxel in the posterior periventricular white matter (WM) using proton MRS. Intracellular pH (pHi) was calculated using phosphorus MRS. Eighteen infants had normal WM on MR imaging; 12 had WMD. For infants with WMD, lactate/Cr and myo-inositol/Cr were related (P < 0.01); lactate/Cr and pHi were not (P = 0.8). In the WMD group, mean lactate/Cr and myo-inositol/Cr were higher (P < 0.001, P < 0.05, respectively) than the normal WM group. There was no difference in the NAA/Cr, Cho/Cr, or pHi between the two groups, although pHi was not measured in all infants. These findings suggest that WMD in the preterm infant at term has a different biochemical profile compared with the term infant after perinatal HI.
Brain↗
Pilot study of treatment with whole body hypothermia for neonatal encephalopathy.
BACKGROUND: There is extensive experimental evidence to support the investigation of treatment with mild hypothermia after birth asphyxia. However, clinical studies have been delayed by the difficulty in predicting long-term outcome very soon after birth and by concern about adverse effects of hypothermia. OBJECTIVES: The objectives of this study were to determine whether it is feasible to select infants with a bad neurological prognosis and to begin hypothermic therapy within 6 hours of birth, and to observe the effect of this therapy on relevant physiologic variables. METHODS: Sixteen newborn infants with clinical features of birth asphyxia (median cord blood pH: 6.74; range: 6.58-7.08) were assessed by amplitude integrated electroencephalography (aEEG), and mild whole body hypothermia was instituted within 6 hours of birth in the 10 infants with an aEEG prognostic of a bad outcome. Rectal temperature was maintained at 33.2 +/- (standard deviation).6 degrees C for 48 hours. Rectal and tympanic membrane temperature, blood pressure, heart rate, blood gases, blood lactate, full blood count, blood electrolytes, high and low shear rate viscosity, and coagulation studies were monitored during and after cooling. A preliminary assessment of neurological outcome was made by repeated magnetic resonance imaging (MRI) and neurological examination. RESULTS: All infants selected to receive hypothermia developed convulsions and a severe encephalopathy. During 48 hours of hypothermia infants had prolonged metabolic acidosis (median pH: 7.30; base excess: -6.3 mmol x L(-1), a high blood lactate (median lactate: 5.3 mmol x L(-1)) and low blood potassium levels (median value: 3.9 mmol x L(-1)) x Hypothermia was associated with lower heart rate and higher mean blood pressure. However, these changes did not seem to be clinically relevant and no significant complication of hypothermia was encountered. Blood viscosity and coagulation studies were similar during and after cooling. Unusual MRI findings were noted in 3 infants: transverse sinus thrombosis with subsequent small cerebellar infarct; probable thrombosis in the straight sinus; and hemorrhagic cerebral infarction. Six of the 10 cooled infants had minor abnormalities only or normal follow-up neurological examination; 3 infants died and 1 had major abnormalities. None of the 6 infants with a normal aEEG developed severe neonatal encephalopathy or neurological sequel. CONCLUSIONS: After birth asphyxia infants can be objectively selected by aEEG and hypothermia started within 6 hours of birth in infants at high risk of developing severe neonatal encephalopathy. Prolonged mild hypothermia to 33 degrees C to 34 degrees C is associated with minor physiologic abnormalities. Further studies of both the safety and efficacy of mild hypothermia, including further neuroimaging studies, are warranted.
Asphyxia Neonatorum↗
Revisited: spinal angiolipoma--three additional cases.
Angiolipomas are benign tumours which usually arise from subcutaneous tissue, particularly in the forearm, but they do occur rarely in the spinal canal. To the best of our knowledge 60 cases of histologically confirmed spinal angiolipoma have been reported in the medical literature. They show a female predominance (1.6:1), and the mean age at presentation is 43 years. They usually arise in the thoracic spine, most cases presenting with slowly progressive signs and symptoms of cord compression. Rarely, massive acute haemorrhage into the tumour may herald its presence. Surgical resection or decompression are the most satisfactory methods of treatment in most patients. We describe three further cases of spinal angiolipoma, and discuss their aetiology, pathogenesis, clinico-pathological features and surgical management.
Adolescent↗
A woman who bled after a decade of dyspnoea.
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Aged↗
Cerebral intracellular lactic alkalosis persisting months after neonatal encephalopathy measured by magnetic resonance spectroscopy.
We have found that cerebral lactate can be detected later than 1 month of age after neonatal encephalopathy (NE) in infants with severe neurodevelopmental impairment at 1 y. Our hypothesis was that persisting lactate after NE is associated with alkalosis and a decreased cell phosphorylation potential. Forty-three infants with NE underwent proton and phosphorus-31 magnetic resonance spectroscopy at 0.2-56 wk postnatal age. Seventy-seven examinations were obtained: 25 aged <2 wk, 16 aged > or = 2 to < or = 4 wk, 25 aged > 4 to < or = 30 wk, and 11 aged > 30 wk. Neurodevelopmental outcome was assessed at 1 y of age: 17 infants had a normal outcome and 26 infants had an abnormal outcome. Using univariate linear regression, we determined that increased lactate/creatine plus phosphocreatine (Cr) was associated with an alkaline intracellular pH (pHi) (p < 0.001) and increased inorganic phosphate/phosphocreatine (Pi/PCr) (p < 0.001). This relationship was significant, irrespective of outcome group or age at time of study. Between outcome groups, there were significant differences for lactate/Cr measured at < 2 wk (p = 0.005) and > 4 to < or = 30 wk (p = 0.01); Pi/PCr measured at < 2 wk (p < 0.001); pHi measured at < 2 wk (p < 0.001), > or = 2 to < or = 4 wk (p = 0.02) and > 4 to < or = 30 wk (p = 0.03); and for N-acetylaspartate/Cr measured at > or = 2 to < or = 4 wk (p = 0.03) and > 4 to < or = 30 wk (p = 0.01). Possible mechanisms leading to this persisting cerebral lactic alkalosis are a prolonged change in redox state within neuronal cells, the presence of phagocytic cells, the proliferation of glial cells, or altered buffering mechanisms. These findings may have implications for therapeutic intervention.
Brain↗
Recent advances in developing neuroprotective strategies for perinatal asphyxia.
Perinatal asphyxia is the most important cause of acute neurologic injury in the newborn and occurs in approximately six per 1000 term live births. After resuscitation of an infant with birth asphyxia, the emphasis has been on supportive therapy; however, there is increasing evidence that a "therapeutic window" exists in the early hours following the insult, and perhaps for longer, when intervention can attenuate activation of the neurotoxic cascade that leads to delayed cell death hours, days or months later.
Asphyxia Neonatorum↗
Randomised trial of elective continuous positive airway pressure (CPAP) compared with rescue CPAP after extubation.
AIM: To determine if a weaning regimen on flow driver continuous positive airway pressure (CPAP) would decrease the number of ventilator days but increase the number of CPAP days when compared with a rescue regimen. METHODS: Fifty eight babies of 24-32 weeks gestation with respiratory distress syndrome (RDS) were studied prospectively. After extubation they were randomly allocated to receive CPAP for 72 hours (n = 29) according to a weaning regimen, or were placed in headbox oxygen and received CPAP only if present "start CPAP" criteria were met (n = 29, rescue group). RESULTS: There was no difference in successful extubation at 72 hours, 1 and 2 weeks, between the groups in terms of the number of reventilation episodes, reventilation days, or in total days of CPAP. Birthweight, gestational age, race, day of first extubation, antenatal or postnatal steroids, patent ductus arteriosus status and maximal mean airway pressure used were of no value in predicting success or failure at 72 hours, 1, or 2 weeks. CONCLUSION: The weaning regimen did not decrease the number of ventilator days or days on CPAP compared with the rescue regimen. The rescue regimen on flow driver CPAP seems to be a safe and effective method of managing a baby of 24-32 weeks gestation who has been ventilated for RDS or immature lung disease.
Humans↗
Intravascular synovial sarcoma.
A case of intravascular biphasic synovial sarcoma arising from the wall of the left femoral vein in a 34 year old woman is described. This is the third case of an intravascular synovial sarcoma known to be reported in the medical literature. The two previous cases arose from the left femoral vein and inferior vena cava in women of 34 and 31 years old, respectively. A characteristic clinical pattern appears to be emerging--that is, location in large veins of the lower extremity and trunk in young adult females. Synovial sarcoma must be considered in the differential diagnosis of intravascular "tumours".
Adult↗
Carcinosarcoma of the oesophagus showing neuroendocrine, squamous and glandular differentiation.
AIM: A case of oesophageal carcinosarcoma occurring in a previously fit, 64-year-old man is reported. CASE SUMMARY: The carcinomatous component displayed neuroendocrine, squamous and glandular differentiation: the sarcomatous component showed no specific features of differentiation. In-situ squamous carcinoma was present in the adjacent squamous mucosa. The most superficial part of invasive tumour consisted of carcinosarcoma with a predominant neuroendocrine epithelial component. Squamous carcinoma without an accompanying sarcomatous component occupied most of the deeper part of the tumour, suggesting outgrowth of this tumour type by a selective growth advantage. CONCLUSION: We speculate that further tumour growth might have led to complete replacement of the tumour by pure squamous carcinoma, and that other advanced oesophageal squamous carcinomas might have had their origin in a short-lived carcinosarcomatous phase.
Adenocarcinoma↗
Salivary duct carcinoma: a cytological and histopathological study.
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Adenocarcinoma↗
Nasal deformities resulting from flow driver continuous positive airway pressure.
Over a period of six months, seven cases were documented of trauma to the nose as a result of flow driver continuous positive airway pressure in babies of very low birthweight (VLBW). There was a complication rate of 20% in the babies who required it. Deformities consisted of columella nasi necrosis which can occur within three days, flaring of nostrils which worsens with duration of continuous positive airway pressure, and snubbing of the nose which persists after prolonged continuous positive airway pressure. These complications should be preventable by modifications to the mechanism and method of use.
Humans↗
Liver giant mitochondria revisited.
AIMS: To examine the correlation between the severity of alcohol induced liver damage and the presence of intracytoplasmic red bodies (defined as periodic acid-Schiff diastase negative, globular, hyaline cytoplasmic inclusions larger in size than the hepatocyte nucleolus). To investigate the incidence of intracytoplasmic red bodies (ICRBs) in non-alcoholic liver disease. METHODS: Liver biopsy specimens from 53 patients with alcoholic liver disease and 50 patients with a variety of nonalcohol related liver diseases were examined by light microscopy for the presence of ICRBs. For the 53 patients with alcoholic liver disease an assessment of recent alcohol consumption was made indirectly from measurements of red cell volume (MCV) and plasma gamma-glutamyl transferase (GGT). In addition, 10 liver biopsies with alcohol induced changes and ICRBs were examined by electron microscopy for the presence of mitochondrial aberrations including enlargement. RESULTS: ICRBs were detected in 18 of the 53 liver biopsy specimens showing alcohol induced changes, and were more abundant in those showing more advanced changes. Those patients whose liver specimens contained ICRBs were found to have a significantly higher mean plasma GGT activity and mean MCV than those individuals whose liver biopsy specimens did not contain ICRBs. Two of the 50 liver biopsy specimens showing non-alcohol induced changes contained ICRBs. Giant mitochondria were not detected by electron microscopy, but this may reflect sampling. CONCLUSIONS: The results of this study indicate that ICRBs are definitely associated with alcoholic liver disease and are more likely to be found in liver biopsy specimens showing more advanced alcohol induced damage, and when recent alcohol consumption has been high.
Adult↗
Fatal overdose from a sustained-release theophylline preparation.
A 26-year-old woman ingested approximately 9 g of theophylline (Theodur). She exhibited agitation, generalized seizures, hyperglycemia, hypokalemia, hypomagnesemia, hypophosphatemia, and diuresis. Later in her hospital course rhabdomyolysis, myoglobinuria, and acute renal failure occurred. Hemodialysis was performed to correct electrolyte imbalance. She subsequently died of intractable shock and hyperkalemia. This case illustrates the metabolic abnormalities which may occur with severe theophylline intoxication.
Adult↗
Evaluation of regional and nonregional poison centers.
The purpose of this study was to determine whether regional poison centers handle a particular poisoning situation better than nonregional centers do. Informed consent was obtained from 15 regional and 15 nonregional poison centers. A case involving salicylate ingestion by a three-year-old child was presented twice (one day call and one night call) to each center. Those answering the phone at the regional centers asked more information-gathering questions than did those at the nonregional centers (P less than 0.01) and were more proficient in their history taking (P less than 0.01). Nonregional centers did not consider the potentially toxic ingestion (220 mg per kilogram of body weight) important enough to treat or were not willing to handle the poisoning in one third of the calls. The nonregional centers recommended manual stimulation to induce emesis in 30 per cent of the calls, whereas none of the regional centers recommended this treatment. Four calls to the nonregional centers resulted in recommendations of inappropriate emetics--e.g., saltwater, raw eggs, or mustard water. The chance of obtaining incorrect recommendations for poisoning treatment from the nonregional centers was determined to be nine times greater than that from the regional centers. Indications of intention to follow up were twice as frequent among regional as among nonregional centers. These data strongly suggest that regional poison centers provide better and more consistent poison information than do nonregional centers.
Child↗
Amphibian organ culture in experimental toxicology: the effects of paracetamol and phenacetin on cultured tissues from urodele and anuran amphibians.
Organ cultures of various tissues from urodele amphibians deacetylate paracetamol to p-aminophenol, which polymerises to form a brown precipitate. Paracetamol addition results in a loss of glycogen and lactate dehydrogenase (LDH) from urodele liver cultures and an increase in glucose release, and in LDH loss from kidney cultures. Organ cultures from anuran amphibians are unable to metabolise paracetamol and are not affected by its presence in the culture medium. The addition of unpolymerised p-aminophenol resulted in a loss of LDH from urodele and anuran organ cultures, whilst the addition of polymerised p-aminophenol had no such effects. This suggests that the toxic effects which follow the addition of paracetamol to urodele organ cultures are caused by unpolymerised p-aminophenol, a known toxicant in mammals. Cultures from both urodele and anuran amphibians are able to deacetylate phenacetin to p-phenetidine, but p-phenetidine was found to be much less toxic to amphibian tissues than p-aminophenol, causing LDH loss from kidney cultures only at very high dose levels.
Acetaminophen↗