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Biomedical subjects

D Dalton

Publications and source records attributed to D Dalton.

At least 19 recordsLinked to original sources
PubMed2004

Bacteraemia and antibiotic use in respiratory syncytial virus infections.

AIMS: To examine the frequency of and risk factors for bacteraemia in children hospitalised with respiratory syncytial virus (RSV) infection; and to determine current use of antibiotics in hospitalised children with RSV infection. METHODS: Retrospective study of all children, aged 0-14 years, admitted to a tertiary children's hospital with proven RSV infection over a four year period. Children with concurrent bacteraemia and RSV infection were identified, and risk factors examined for bacteraemia. The case notes of a randomly selected comparison sample of 100 of these RSV infected children were examined to assess antibiotic use and population incidence of risk factors for severe RSV infection. RESULTS: A total of 1795 children had proven RSV infection, and blood cultures were sent on 861 (48%). Eleven (0.6%) of the 1795 RSV positive children had bacteraemia. RSV positive children had a significantly higher incidence of bacteraemia if they had nosocomial RSV infection (6.5%), cyanotic congenital heart disease (6.6%), or were admitted to the paediatric intensive care unit (2.9%). Forty five (45%) of the random comparison sample of RSV infected children received antibiotics. CONCLUSIONS: Bacteraemia is rare in RSV infection. Children with RSV infection are more likely to be bacteraemic, however, if they have nosocomial RSV infection, cyanotic congenital heart disease, or require intensive care unit admission.

Adolescent↗
PubMed1999

Outbreak of extended spectrum beta lactamase producing Klebsiella pneumoniae in a neonatal unit.

An outbreak of extended spectrum beta lactamase producing Klebsiella pneumoniae (ESBLKp) in a neonatal unit was controlled using simple measures. Normally, the control of such infections can be time consuming and expensive. Seven cases of septicaemia resulted in two deaths. ESBLKp isolates were subtyped by pulsed field gel electrophoresis, and four of the five isolates typed were identical. Control of the outbreak was achieved by altered empiric antibiotic treatment for late onset sepsis and prevention of cross infection by strict attention to hand washing. Widespread colonisation of babies in the unit was presumed, so initial surveillance cultures were not performed. No further episodes of sepsis occurred.

Amikacin↗
PubMed1997

Interferon-gamma protects against herpes simplex virus type 1-mediated neuronal death.

Host inflammatory mediators, such as interferons, play a protective role in infection, but the mechanism is undefined and may differ between tissue compartments. To determine whether interferon-gamma (IFN-gamma) elicitation prevents destructive encephalitis in herpes simplex virus type 1 (HSV-1) infection of the central nervous system, IFN-gamma-knockout (GKO) mice were challenged intravitreally with HSV-1 strain F, inciting infection of the eyes and the brain. Indeed, the GKO mice showed encephalitis with ataxia, whereas nontransgenic controls remained asymptomatic. Morphology and digoxigenin labeling of DNA fragments revealed increased apoptosis in the brains of GKO mice compared with controls, although viral replication was not influenced at early stages of infection. Greater numbers of apoptotic cells in the brains of GKO mice correlated with neurological symptoms, as well as lower expression of the protective protooncogene bcl-2. Thus, IFN-gamma inhibits apoptosis, affording neuronal protection from destructive encephalitis during viral infection of the central nervous system.

Animals↗
PubMed1997

Rate of seasonal spread of respiratory syncytial virus in a pediatric hospital.

The rate of nosocomial respiratory syncytial virus (RSV) infection was measured in a large pediatric hospital using an incidence density method. The at-risk days for nosocomial RSV were summed during a defined winter period in which there were 54 admissions with community-acquired RSV infection giving a rate of 2.9 cases per 1,000 at-risk days (95% confidence interval, 0.3-5.4 per 1,000).

Community-Acquired Infections↗
PubMed1996

Mice with a disrupted IFN-gamma gene are susceptible to the induction of experimental autoimmune encephalomyelitis (EAE).

Experimental autoimmune encephalomyelitis (EAE), an animal model for multiple sclerosis, is an autoimmune disorder seen in mice and rats following immunization with myelin basic protein (MBP) or MBP-derived peptides. IFN-gamma, a cytokine produced by a variety of cells, is involved in many inflammatory and immune regulatory events. Contradictory results concerning exacerbations and the disease course were seen comparing injections of IFN-gamma in humans suffering from multiple sclerosis to studies using anti-IFN-gamma Abs in mice with EAE. To study the role of IFN-gamma and IFN-gamma-producing cells in EAE, we crossed IFN-gamma knockout mice (H-2b) (unable to produce IFN-gamma due to the disruption of the IFN-gamma gene) with an EAE-susceptible mouse strain, B10.PL (H-2u). EAE was seen in IFN-gamma knockout mice, heterozygotic (IFN-gamma +/-) mice, as well as wild-type littermates following immunization with MBP. Histologic analyses of the central nervous system of IFN-gamma knockout mice with EAE revealed massive infiltrates composed of lymphocytes, macrophages, and granulocytes. We conclude that the presence of IFN-gamma is not crucial to the induction or the clinical course of EAE.

Animals↗
PubMed1996

Repeated prevalence surveys of paediatric hospital-acquired infection.

Hospital-acquired infection (HAI) results in an enormous burden of excess morbidity, mortality and cost in both adults and children. Monitoring HAI is difficult, especially with limited resources, but it is vital if infection control measures are to be appropriately implemented and assessed. Cross-sectional prevalence surveys, repeated every six months, have been used effectively to monitor HAI in adults, but this technique has not been previously employed in the paediatric population. We performed prevalence surveys of HAI on a single day once every six months for five years, using a standardized questionnaire. Of the 1623 inpatients surveyed, 125 (7.7%) had HAI and 352 (21%) had community-acquired infection. In those with HAI, central-line infections, pneumonia, and wound infections predominated. A hospital stay of greater than seven days was associated with a sixfold increase in the risk of HAI. In addition, admission to a paediatric or neonatal intensive care unit, the presence of a urinary or vascular catheter, the presence of an endotracheal tube, immunosuppression and recent surgery were all associated with a significantly increased risk of HAI. In contrast to other studies, younger children were not at increased risk of HAI; admission to the neonatal unit, rather than age per se, was associated with increased risk. We conclude that repeated prevalence surveys enable simple and cost-effective assessment of HAI, facilitating appropriate infection control interventions. They should be used more widely in the paediatric setting.

Age Factors↗
PubMed1995

The incidence of prostate cancer progression with undetectable serum prostate specific antigen in a series of 394 radical prostatectomies.

PURPOSE: Serum prostate specific antigen (PSA) has been reported to be a sensitive indicator of recurrent carcinoma after radical prostatectomy but it is not absolute. Disease progression with undetectable PSA levels has been described but the incidence of this phenomenon is unknown. MATERIALS AND METHODS: We retrospectively analyzed the records of 394 consecutive men who underwent radical prostatectomy between 1980 and 1991 to characterize the incidence of recurrent carcinoma despite undetectable serum PSA levels. RESULTS: Of the 394 men 133 had documented evidence of disease recurrence, 3 (2.3%) despite undetectable serum PSA levels (2 had local and systemic evidence of disease progression). Histological dedifferentiation characterized these recurrences. CONCLUSIONS: Although a post-prostatectomy detectable serum PSA level precedes clinical evidence of disease progression by years, rare patients (2.3% in our series) in whom recurrent disease is characterized by marked histological dedifferentiation will remain negative for PSA.

Aged↗
PubMed1993

IGF-I is required for normal embryonic growth in mice.

IGF-I is a pleiotropic hormone reported to affect linear growth, glucose metabolism, organ homeostasis, and the immune and neurologic systems. In contrast to IGF-II, IGF-I is expressed at low levels embryonically and has been thought to be more important for postnatal growth and development. To investigate the role of IGF-I in normal development we generated mice with an inactive IGF-I gene by homologous recombination in ES cells. Heterozygous mice are healthy and fertile, but they are 10-20% smaller than wild-type littermates and have lower than normal levels of IGF-I. The size reduction is attributable to a decrease in organs and muscle and bone mass. However, all tissues appear histologically normal. At birth homozygous mutant mice (IGF-I-/-) are < 60% body weight of wild type. Greater than 95% of IGF-I-/- pups die perinatally. Histopathology is characterized by underdevelopment of muscle tissue. Lungs of late embryonic and neonates also appeared less organized with ill-defined alveolae. IGF-I appears to be essential for correct embryonic development in mice.

Animals↗
PubMed1989

Silicone foam dressing for penis after reconstructive pediatric surgery.

Although silicone foam has been used abroad as an effective means to dress the penis after hypospadias surgery, its use has not been widespread in the United States. We have modified the method to apply the foam in order to facilitate its use. We used this method to dress the penis with silicone foam in 50 boys after reconstructive surgery. The dressing appeared to be effective in restricting edema and hematoma formation. Also, the dressing stabilized the indwelling urethral catheter thereby preventing disruption of the glansplasty. The urethrocutaneous fistula rate (10%) was not reduced by use of the foam. The dressings uncommonly fell off prematurely. The boys appeared to experience little discomfort while the foam was in place and during its removal.

Bandages↗
PubMed1989

Expression and embryonic function of empty spiracles: a Drosophila homeo box gene with two patterning functions on the anterior-posterior axis of the embryo.

Using the even-skipped homeo box as a probe to identify diverged homeo box genes in the Drosophila genome, we isolated the empty spiracles (ems) gene. Structural and functional comparisons between ems and other embryonic patterning genes of Drosophila suggest that ems acts, in part, as a homeotic selector gene, specifying the identity of some of the most anterior head segments. Mutant embryos lacking ems protein have severe patterning defects in the anterior head and are missing tracheal structures, including the filzkörper, which are normally developed by the eighth abdominal segment. ems has two different spatial patterns of expression during embryogenesis. The early, head-specific pattern consists of a single anterior stripe at the syncytial and cellular blastoderm stages. The later, metameric pattern consists of bilateral patches of ems expression in neural and ectodermal cells of every head and body segment. Variations of the ems expression pattern in bicoid mutants suggests that the morphogen protein produced by bicoid has a concentration-dependent regulatory role in the establishment of head-specific ems expression. In contrast, the metameric ems pattern is initiated independently of bicoid protein, and ems becomes expressed at high levels in the primordia of the duplicated fïlzkörper that develop in the anterior half of bicoid mutant embryos.

Amino Acid Sequence↗
PubMed1986

The natural history of simple renal cysts: a preliminary study.

We examined the natural history of simple renal cysts in 59 patients followed periodically with renal ultrasonography. Using the parameters of cyst diameter and number we grouped the patients according to the differing natural history of the cystic lesions. The results indicate that simple cysts tend to progress in number rather than size. Furthermore, 3 patients had independent solid or complex lesions. The only patient explored had an adenocarcinoma of the kidney. Periodic reevaluation of patients with an ultrasonic diagnosis of simple renal cyst warrants serious consideration.

Adult↗
PubMed1986

Ruptured thoracic aneurysm: unusual manifestation and early diagnosis using CT.

Rupture of a thoracic aortic aneurysm across the posterior mediastinum into the right side of the chest is rare. The diagnosis may be delayed by the absence of expected findings in the left side of the chest. We recently encountered two patients with thoracic aneurysm rupture who came to medical attention initially because of right-sided pleural and/or extrapleural hematomas, which were accurately diagnosed preoperatively on the basis of computed tomography (CT) findings. Aortography, performed in one patient, added no useful information. Because CT accurately identifies the presence of pleural or extrapleural blood, as well as the underlying aneurysm or dissection, CT should be the first examination performed in cases of suspected thoracic aneurysm rupture.

Aged↗