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Biomedical subjects

N Young

Publications and source records attributed to N Young.

At least 19 recordsLinked to original sources

Cementifying fibroma of the frontal bone: a case report.

Cementifying fibromas are rare fibro-osseous tumours that are usually found in the jaws. We report a 10-year-old boy who presented with a mass in the frontal bone causing frontal bossing and proptosis. The preoperative diagnosis was not clear despite computed tomographic and magnetic resonance imaging. The lesion was resected completely and found to be a cementifying fibroma. It was reconstructed at the same operation and he made a good recovery with no sign of recurrence.

Child↗

Superselective coil embolization in gastrointestinal haemorrhage: early experience.

This is a retrospective study to evaluate our early experience of using selective microcoil embolization in patients who had gastrointestinal (GI) haemorrhage. From December 2002 to December 2003, six patients with GI haemorrhage (upper GI, n = 1; lower GI, n = 5) underwent superselective microcoil embolization. Microcatheters were used to carry out embolizations in branches of the superior mesenteric artery. Microcoils were used in five patients and a combination of microcoils and embolospheres was used in one patient. Technical success (bleeding target devascularization) was achieved in all patients who showed active bleeding at the time of angiography. Two patients had recurrent bleeding within 24 h of embolization, of which one (16.7%) died. The other patient did not require active intervention as bleeding was minimal and resolved with conservative management. Satisfactory clinical success (no rebleeding after 30 days) was achieved in five patients. No clinical signs and symptoms of bowel ischaemia occurred in these patients. Follow-up colonoscopy carried out in two patients did not show any signs of ischaemia in the affected bowel segments. Superselective microcoil embolization is an effective and safe method of controlling and arresting bleeding in GI haemorrhage.

Aged↗

Accuracy of computed tomography in the detection of blunt bowel and mesenteric injuries.

BACKGROUND: There are conflicting views on the accuracy of computed tomography (CT) findings in patients with bowel and mesenteric injuries (BMIs) following blunt abdominal trauma. The aim of the present study was to assess the accuracy of the CT report during a trauma call. METHODS: Ninety-eight patients underwent preoperative abdominal spiral CT and subsequent laparotomy following blunt trauma between January 1996 and March 2001 at a level I trauma centre. The immediate results of the scans were reported by the on-call radiology registrar and written in the medical notes by the trauma team leader. Seventy of the 98 preoperative abdominal CT scans were retrieved from the radiology department and reported by two consultant radiologists with a special interest in trauma radiology. RESULTS: The sensitivity and specificity of the 70 expert CT reports were 80 (95 per cent confidence interval (c.i.) 66 to 94) and 78 (95 per cent c.i. 65 to 90) per cent respectively for diagnosing a BMI. The sensitivity and specificity of the immediate CT reports were 93 (95 per cent c.i. 84 to 100) and 71 (95 per cent c.i. 60 to 83) per cent respectively. CONCLUSION: Spiral CT is highly sensitive for detecting a BMI following blunt abdominal trauma. This sensitivity is maintained when the scan is reported by a radiology registrar.

Abdominal Injuries↗

Education and training in psychosocial interventions: a survey of Thorn Initiative course leaders.

The Thorn Initiative is a prominent education and training programme for psychosocial interventions. The course originated in two centres in the UK in 1992, 10 years on the programme had expanded to 13 centres across England and Wales. A survey of course content and structure was sent out to all 13 sites by email of which eight responded by post. The survey results showed that since 1999 there has been a rapid growth in the number of Thorn sites. There remains a high degree of fidelity to the original courses in mode of delivery, service user and carer participation, and core content. All of the sites were progressing towards providing degree courses, usually in a modular format and with an expanded curriculum. In conclusion, the Thorn Steering Group has been successful in Thorn site expansion and curriculum development. Such success has taken activity away from audit and research in psychosocial interventions, education, training, implementation and fidelity to taught skills. Implementation remains a cause for concern and it is recommended that a focus for Thorn sites should be on creating and evaluating novel solutions to this pervasive problem.

Cooperative Behavior↗

Sex-steroid derived compounds induce sex-specific effects on autonomic nervous system function in humans.

The physiological and psychological effects of 2 human sex-steroid derived compounds, 4.16-androstadien-3-one (AND) and l,3,5(10),16-estratetraen-3-ol(EST) were measured in 24 subjects who participated in a within-subjects, double-blind experiment. A dissociation was evident in the physiological effects of AND, in that it increased physiological arousal in women but decreased it in men. EST did not significantly affect physiological arousal in women or men. Neither compound significantly affected mood. AND is an androgen derivative that is the most prevalent androstene in human male sweat, male axillary hair, and on the male axillary skin surface. The authors argue that AND's opposite effects on physiology in men and women further implicate this compound in chemical communication between humans.

Adult↗

Crystal structure of glycogen synthase kinase 3 beta: structural basis for phosphate-primed substrate specificity and autoinhibition.

Glycogen synthase kinase 3 beta (GSK3 beta) plays a key role in insulin and Wnt signaling, phosphorylating downstream targets by default, and becoming inhibited following the extracellular signaling event. The crystal structure of human GSK3 beta shows a catalytically active conformation in the absence of activation-segment phosphorylation, with the sulphonate of a buffer molecule bridging the activation-segment and N-terminal domain in the same way as the phosphate group of the activation-segment phospho-Ser/Thr in other kinases. The location of this oxyanion binding site in the substrate binding cleft indicates direct coupling of P+4 phosphate-primed substrate binding and catalytic activation, explains the ability of GSK3 beta to processively hyperphosphorylate substrates with Ser/Thr pentad-repeats, and suggests a mechanism for autoinhibition in which the phosphorylated N terminus binds as a competitive pseudosubstrate with phospho-Ser 9 occupying the P+4 site.

Animals↗

A mutation in the Gsk3-binding domain of zebrafish Masterblind/Axin1 leads to a fate transformation of telencephalon and eyes to diencephalon.

Zebrafish embryos homozygous for the masterblind (mbl) mutation exhibit a striking phenotype in which the eyes and telencephalon are reduced or absent and diencephalic fates expand to the front of the brain. Here we show that mbl(-/-) embryos carry an amino-acid change at a conserved site in the Wnt pathway scaffolding protein, Axin1. The amino-acid substitution present in the mbl allele abolishes the binding of Axin to Gsk3 and affects Tcf-dependent transcription. Therefore, Gsk3 activity may be decreased in mbl(-/-) embryos and in support of this possibility, overexpression of either wild-type Axin1 or Gsk3beta can restore eye and telencephalic fates to mbl(-/-) embryos. Our data reveal a crucial role for Axin1-dependent inhibition of the Wnt pathway in the early regional subdivision of the anterior neural plate into telencephalic, diencephalic, and eye-forming territories.

Animals↗

HIV seroconversion during pregnancy and risk for mother-to-infant transmission.

Pregnant women infected with HIV-1 were enrolled in a prospective mother-to-infant transmission study from 1992 through 1994 in Bangkok. In participating hospitals, voluntary HIV testing was routinely offered at the beginning of antenatal care and again in the middle of the third trimester of pregnancy. Women who seroconverted to HIV during pregnancy were compared with women who had tested positive on their first antenatal test. Maternal HIV RNA levels were determined during pregnancy, at delivery, and postpartum using RNA polymerase chain reaction (PCR), and infection status in infants was determined by DNA PCR. No infants were breast-fed, but prophylactic antiretroviral therapy was not yet used in Thailand to prevent transmission from mother to infant. Among enrolled women, 16 who seroconverted during pregnancy and 279 who were HIV-1-seropositive at their first antenatal test gave birth. Median plasma RNA levels at delivery were similar for the two groups (17,505 and 20,845 copies/ml, respectively; p =.8). Two (13.3%) of 15 infants born to women who seroconverted and 66 (24.8%) of 266 infants born to previously HIV-seropositive women were infected with HIV (p =.5). There was no increased risk for mother-to-infant HIV transmission and no significant difference in viral load at delivery between HIV-infected women who seroconverted to HIV during pregnancy and those who were HIV-seropositive when first tested.

Adult↗

The clinical meaning of functional outcome scores in children with juvenile arthritis.

OBJECTIVE: The Childhood Health Assessment Questionnaire (CHAQ) is the most widely used measure of function in childhood arthritis and yields a score of 0 (no disability) to 3 (very severe disability). This study ascertained the cutoff levels for CHAQ scores that represent no, mild, moderate, and severe disability, to determine the minimal clinically important change in scores and to determine whether the minimal important change in scores is similar for parent-reported assessments and the self-assessments provided by their older children. METHODS: One hundred thirty-six parents of children with arthritis were interviewed. They were asked to complete the CHAQ by assessing their child's functional status under 3 categories: current health, a hypothetical small improvement, and a hypothetical small worsening. They also completed a categorical scale of subjective disability. Those children who were > or = 10 years old also completed the CHAQ interview separately. RESULTS: The pediatric patients had mostly no, mild, or moderate disability. For those children rated as having no disability, the median CHAQ score was 0. The median CHAQ scores corresponding to mild, mild-to-moderate, and moderate disability were 0.13, 0.63, and 1.75, respectively. The minimal clinically important improvement was a reduction in score of 0.13. The minimal clinically important deterioration was a median change in score of 0.75. This discrepancy may be due to the ceiling effect seen with the CHAQ. There were no significant differences when the children assessed themselves. CONCLUSION: Clinicians, as well as researchers setting protocols, should aim for a mimimum improvement of 0.13 in the CHAQ score when treating pediatric patients with arthritis.

Arthritis, Juvenile↗

Intracranial aneurysms: evaluation in 200 patients with spiral CT angiography.

The goal of this study was to assess the usefulness of spiral CT angiography (CTA) with three- dimensional reconstructions in defining intracranial aneurysms, particularly around the Circle of Willis. Two hundred consecutive patients with angiographic and/or surgical correlation were studied between 1993 and 1998, with CTA performed on a GE HiSpeed unit and Windows workstation. The following clinical situations were evaluated: conventional CT suspicion of an aneurysm; follow-up of treated aneurysm remnants or of untreated aneurysms; subarachnoid haemorrhage (SAH) and negative angiography; family or past aneurysm history; and for improved definition of aneurysm anatomy. Spiral CTA detected 140 of 144 aneurysms, and an overall sensitivity of 97%, including 30 of 32 aneurysms 3 mm or less in size. In 38 patients with SAH and negative angiography, CTA found six of the seven aneurysms finally diagnosed. There was no significant artefact in 17 of 23 patients (74%) with clips. The specificity of CTA was 86% with 8 false-positive cases. Spiral CTA is very useful in demonstrating intracranial aneurysms.

Adolescent↗

EVT endovascular graft for abdominal aortic aneurysm.

BACKGROUND: A variety of prostheses are now available for the endovascular treatment of abdominal aortic aneurysm (AAA). Significant advantages of the EVT device are its unibody design, secure hook attachment system and graft fabric approximating that used in conventional surgery. METHODS: Implantation of the EVT device was attempted in 60 patients who were studied prospectively with an analysis of subsequent problems encountered. RESULTS: Conversion to open repair was required in four cases (6.7%). There were nine tube grafts inserted, 13 aorto-unilateral iliac with crossover grafts and 34 aorto-bi-iliac grafts. There was one death (mortality 1.7%). Endoleaks were identified in eight patients (14%), none of which were proximal; three sealed spontaneously, two were treated with coil embolization, two are being observed and one patient had an iliac attachment converted to an open anastomosis. Access vessel problems were seen in 21 patients (35%); two-thirds were corrected at the time of initial surgery. Seven patients (12%) had primary graft limb problems identified and treated before leaving the operating room. Nine patients (16%) developed secondary graft limb problems, which were diagnosed and treated after the initial surgery. Endovascular treatment was used in eight and was successful in six with surgical revision required in two. On review of these cases to assess if the problem could have been predicted at the time of initial surgery, it was felt that more aggressive treatment of intraoperatively diagnosed graft limb stenoses, even though considered mild, may have prevented 50% of subsequent secondary graft limb occlusions. CONCLUSION: Although the EVT device has significant advantages in the endovascular management of aortic aneurysm, potential graft limb problems need to be actively identified with the majority able to be successfully managed by supplementary endovascular techniques.

Aged↗

Comparison of spiral CT angiography with conventional digital subtraction angiography in the evaluation of renal transplant donors: a pilot study.

Conventional digital subtraction renal arteriography (IA-DSA) has been traditionally used as the preoperative imaging modality for assessment of renal vascular anatomy for renal transplant donors. This study evaluates the potential use of spiral CT angiography in replacing IA-DSA in the preoperative assessment of this group of patients. Seven patients underwent both spiral CT angiography and IA-DSA between October 1997 and April 1998. It is concluded that spiral CT angiography can demonstrate the number, length and location of renal arteries and it is suggested that spiral CT angiography can potentially replace IA-DSA in the preoperative assessment of renal donors.

Adult↗

Oral oseltamivir treatment of influenza in children.

BACKGROUND: Oral oseltamivir administration is effective treatment for influenza in adults. This study was conducted to determine the efficacy, safety and tolerability of oseltamivir in children with influenza. METHODS: In this randomized, double blind, placebo-controlled study, children 1 through 12 years with fever [> or =100 degrees F (> or =38 degrees C)] and a history of cough or coryza <48 h duration received oseltamivir 2 mg/kg/dose or placebo twice daily for 5 days. The primary efficacy endpoint was the time to resolution of illness including mild/absent cough and coryza mild/absent, return to normal activity and euthermia. RESULTS: Of 695 enrolled children 452 (65%) had influenza (placebo, n = 235; oseltamivir, n = 217). Among infected children the median duration of illness was reduced by 36 h (26%) in oseltamivir compared with placebo recipients (101 h; 95% confidence interval, 89 to 118 vs. 137 h; 95% confidence interval, 125 to 150; P < 0.0001). Oseltamivir treatment also reduced cough, coryza and duration of fever. New diagnoses of otitis media were reduced by 44% (12% vs. 21%). The incidence of physician-prescribed antibiotics was significantly lower in influenza-infected oseltamivir (68 of 217, 31%) than placebo (97 of 235, 41%; P = 0.03) recipients. Oseltamivir therapy was generally well-tolerated, although associated with an excess frequency of emesis (5.8%). Discontinuation because of adverse events was low in both groups (1.8% with oseltamivir vs. 1.1% with placebo). Oseltamivir treatment did not affect the influenza-specific antibody response. CONCLUSIONS: Oral oseltamivir administration is an efficacious and well-tolerated therapy for influenza in children when given within 48 h of onset of illness.

Acetamides↗

Telomere length dynamics in normal individuals and in patients with hematopoietic stem cell-associated disorders.

The telomere length in nucleated peripheral blood (PB) cells indirectly reflects the mitotic history of their precursors: the hematopoietic stem cells (HSCs). The average length of telomeres in PB leukocytes can be measured using fluorescence in situ hybridization and flow cytometry (flow FISH). We previously used flow FISH to characterize the age-related turnover of HSCs in healthy individuals. In this review, we describe results of recent flow FISH studies in patients with selected hematopoietic stem cell-associated disorders: chronic myelogenous leukemia (CML) and several bone marrow failure syndromes. CML is characterized by a marked expansion of myeloid Philadelphia chromosome positive (Ph+) cells. Nevertheless, nonmalignant (Ph-) HSCs typically coexist in the bone marrow of CML patients. We analyzed the telomere length in > 150 peripheral blood leukocytes (PBLs) and bone marrow samples of patients with CML as well as samples of Ph- T-lymphocytes. Compared to normal controls, the overall telomere fluorescence in PBLs of patients with CML was significantly reduced. However, no telomere shortening was observed in Ph- T-lymphocytes. Patients in late chronic phase (CP) had significantly shorter telomeres than those assessed earlier in CP. Our data suggest that progressive telomere shortening is correlated with disease progression in CML. Within the group of patients with bone marrow failure syndromes, we only found significantly shortened telomeres (compared to age-adjusted controls) in granulocytes from patients with aplastic anemia (AA). Strikingly, the telomere length in granulocytes from AA patients who had recovered after immunosuppressive therapy (recAA) did not differ significantly from controls, whereas untreated patients and nonresponders with persistent severe pancytopenia (sAANR) showed marked and significant telomere shortening compared to healthy donors and patients with recAA. Furthermore, an inverse correlation between age-adjusted telomere length and peripheral blood counts was found in support of a model in which the degree of cytopenia and the amount of telomere shortening are correlated. These results support the concept of extensive proliferation of HSCs in subgroups of AA patients and suggest a potential use of telomere-length measurements as a prognostic tool in this group of disorders as well.

Anemia, Aplastic↗

Safety of late in utero exposure to zidovudine in infants born to human immunodeficiency virus-infected mothers: Bangkok. Bangkok Collaborative Perinatal HIV Transmission Study Group.

BACKGROUND: Short-course zidovudine (ZDV) given in the late antenatal period can reduce mother-infant human immunodeficiency virus (HIV) transmission by one half. Because this intervention is being implemented in developing countries, evidence of its safety is needed. METHODS: In a randomized, double-blinded, placebo-controlled trial in Bangkok, HIV-infected pregnant women received either ZDV (300 mg twice daily from 36 weeks' gestation until labor, then every 3 hours until delivery) or an identical placebo regimen. Infants were evaluated at birth and at 1, 2, 4, 6, 9, 12, 15, and 18 months of age. Growth, clinical events, and hematologic and immunologic measurements were compared between treatment groups. RESULTS: Of the 395 children born (196 in ZDV group and 199 in placebo group), 330 were uninfected, 55 were infected, and 10 had indeterminate infection status. Overall, 319 children (81%) completed 18 months of follow-up, and 14 (4%) died before 18 months of age. Among uninfected children, the mean hematocrit was lower in the ZDV group at birth (49.1% vs 51.5%) but not at later ages; mean weight, height, head circumference, and CD4(+) and CD8(+) T lymphocyte counts were similar in both groups at all ages. Five uninfected children in the ZDV group but only one in the placebo group had a febrile convulsion. No other signs suggestive of mitochondrial dysfunction and no tumors were observed. Among infected children, an estimated 62% in the ZDV group and 77% in the placebo group survived free of Centers for Disease Control and Prevention class C disease during the 18-month follow-up. CONCLUSIONS: No significant adverse events were associated with short-course ZDV during 18 months of follow-up in this population.

Acquired Immunodeficiency Syndrome↗