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Biomedical subjects

D Adams

Publications and source records attributed to D Adams.

At least 55 records · Page 3Linked to original sources
PubMed2001

Ruptured abdominal aortic aneurysms: clinical presentation in Auckland 1993-1997.

BACKGROUND: Rupture of an abdominal aortic aneurysm (RAAA) carries a reported mortality rate in the range of 32-95%. Survival requires prompt diagnosis and surgical management. The presenting features, however, are varied, often insidious and potentially misleading with Osler noting nearly 100 years ago that a correct premortem diagnosis was achieved in only 33% of cases. The present study aims to review our present accuracy in diagnosing this condition and outline demographic and presenting features of patients with RAAA. METHODS: A review was undertaken of hospital and Coroner's files of all patients residing in the Auckland Coronial region who had RAAA between 1 January 1993 and 31 December 1997. RESULTS: Three hundred and twenty-nine cases of RAAA were identified, and they occurred most commonly in the 8th decade. The male:female ratio was 3:1 and at least 73% of patients were Caucasian. The overall mortality was 71%. Nearly half underwent surgery and the hospital averaged mortality rate was 46%. No patient survived without surgery. Classic presenting features of RAAA were absent in many cases. Abdominal pain, back pain and a palpable mass occurred in only 49%, 36% and 18% of patients, respectively. Other common presenting symptoms included vomiting, general malaise and pelvic or hip pain. Forty-three patients (16%) were initially misdiagnosed. CONCLUSIONS: Although our ability to correctly diagnose a RAAA has improved since Osler's time, the initial misdiagnosis rate of 16% leaves no room for complacency. Ruptured abdominal aortic aneurysms must be included in the differential diagnosis of any patient over the age of 55 years who presents with shock, even if the pain is non-specific or atypical.

Aged↗
PubMed2000

Purification of salmon clotting factors and their use as tissue sealants.

Fibrin sealant prepared from the blood of farmed Atlantic salmon (Salmo salar) represents a potential source of well-controlled natural material with utility in a variety of clinical settings. A potential advantage of this material is a lower probability of viral or bacterial infection that has limited general approval of fibrin glues made from human or bovine proteins. This report describes the purification of fibrinogen from salmon blood, the use of fibrin glues derived from this material to promote wound healing in rats, and the antigenic response to this material. While the low ambient temperature of these cold water fish significantly lessens the probability of infectious transmission to humans, fibrinogen and factor XIII derived from S. salar are activated by human thrombin at 25 degrees C and 37 degrees C to form clots equivalent to those formed by human fibrin. We compare the reactivity of salmon and human fibrinogen with human and bovine thrombin and the structure and viscoelastic properties of the resulting fibrin gels over a range of pH and salt concentrations. The efficacy of salmon fibrin glues in a wound healing assay and the low antigenic response to salmon fibrinogen suggest that this material may substitute for proteins derived from mammalian sources with lower probability of infections.

Animals↗
PubMed2000

Induction of long-term protective effects against heterologous challenge in SIVhu-infected macaques.

A group of three rhesus macaques were inoculated with SIV isolated from a human (SIVhu) accidentally exposed and infected with SIVsm. Extensive sequence analyses of SIVhu obtained from the human and macaques following infection indicated the presence of truncated nef. Not only did nef fail to repair itself in vivo postinfection (p.i.), but instead, further mutations added additional stop codons with increasing time p.i. Infection of these animals was associated with minimal acute viral replication, followed by undetectable plasma viral loads and only intermittent PCR detection up to 5 years p.i. The three SIVhu infected and three control monkeys were then challenged with the heterologous highly pathogenic SHIV89.6p. All three controls became infected and showed rapid declines in peripheral CD4(+) lymphocytes, disease, and death at 10 and 32 weeks p.i., respectively. In contrast, all three animals previously infected with SIVhu are healthy and exhibit stable CD4(+) lymphocyte levels and undetectable plasma viral loads at >20 months post-SHIV89. 6p challenge. Only transient, low levels of SHIV replication were noted in these animals. Whereas responses to SIVgag/pol were noted, no evidence for SIV/SHIV envelope cross-reactivity was detected by antibody or CTL analyses, suggesting that the protective immune mechanisms to the heterologous challenge isolate were most likely not directed to envelope but rather to other viral determinants.

Animals↗
PubMed2000

Phylogeography of mitochondrial DNA variation in brown bears and polar bears.

We analyzed 286 nucleotides of the middle portion of the mitochondrial cytochrome b gene of 61 brown bears from three locations in Alaska and 55 polar bears from Arctic Canada and Arctic Siberia to test our earlier observations of paraphyly between polar bears and brown bears as well as to test the extreme uniqueness of mitochondrial DNA types of brown bears on Admiralty, Baranof, and Chichagof (ABC) islands of southeastern Alaska. We also investigated the phylogeography of brown bears of Alaska's Kenai Peninsula in relation to other Alaskan brown bears because the former are being threatened by increased human development. We predicted that: (1) mtDNA paraphyly between brown bears and polar bears would be upheld, (2) the mtDNA uniqueness of brown bears of the ABC islands would be upheld, and (3) brown bears of the Kenai Peninsula would belong to either clade II or clade III of brown bears of our earlier studies of mtDNA. All of our predictions were upheld through the analysis of these additional samples.

Animals↗
PubMed2000

Optimal gestational age for twin delivery.

OBJECTIVE: We evaluated the timing of twin delivery associated with perinatal outcome in gestations of at least 36 completed weeks. STUDY DESIGN: This was a retrospective analysis of infant and maternal hospital records for a consecutive series of twin deliveries at New York Hospital-Cornell Medical Center. The inclusion criteria were delivery after 36 weeks' gestation during a 7-year period (1987 to 1993), without congenital anomalies or early fetal demise. Adverse perinatal outcomes were compared between deliveries before 38 weeks' gestational age and those at or after 38 weeks' gestation. RESULTS: Of 776 twin deliveries during the study period, 329 met the inclusion criteria. Adverse perinatal outcome was significantly higher among the twin pregnancies that delivered before 38 weeks' gestation compared with those that delivered at or after 38 weeks' gestation. Twin pregnancies that delivered between 36 and 37 weeks' gestation were 13 times more likely to require neonatal intensive care compared with those who delivered at or after 38 weeks' gestation (95% confidence interval 1.8 to 95.9; p < 0.001). CONCLUSION: In uncomplicated twin gestations, delivery at between 36 and 37 weeks' gestation was not associated with a reduction in neonatal complications compared with deliveries at or after 38 weeks' gestation.

Adult↗
PubMed2000

Vascular control for resection of suprahepatic intracaval Wilms' tumor: technical considerations.

The surgical resection of Wilms' tumor can be complicated by tumor thrombus extension into the inferior vena cava. In cases of suprahepatic Wilms' tumor thrombus that may extend into the right atrium, a median sternotomy and cardiopulmonary bypass (CPB) are used to facilitate tumor resection. However, if the tumor can be localized and controlled below the atrium, resection without the use of cardiopulmonary bypass may limit morbidity. The authors describe a novel approach to tumor thrombectomy for a Wilms' tumor extending to the suprahepatic vena cava without the use of CPB. The authors used transesophageal echocardiography to localize the tumor thrombus and detect any tumor or air embolization and a minimal lower sternotomy to obtain intrapericardial control of the inferior vena cava. This technique may be useful in selected cases of Wilms' tumor as an alternative to median sternotomy and use of cardiopulmonary bypass.

Child, Preschool↗
PubMed2000

The course and prognostic factors of familial amyloid polyneuropathy after liver transplantation.

Familial amyloid polyneuropathy (FAP) associated with mutations of the transthyretin (TTR) gene is the most common type of FAP, a devastating disease causing death within 10 years after the first symptoms. Because most of the amyloidogenic mutated TTR is secreted by the liver, transplantation is widely used to treat these patients, but long-term quantitative evaluation of the effects of liver transplantation on the progression of the neuropathy are not available. We have treated 45 patients with symptomatic TTR-FAP, including 43 with the Met30 TTR gene mutation, and report on the results of periodic evaluation of markers of neuropathy in 25 of them, who have been followed for more than 2 years after liver transplantation (mean follow-up 4 years). The overall survival rates at 1 and 5 years were 82 and 60%, respectively. Urinary incontinence and a low Norris score at liver transplantation were associated with poorer outcome. The motor score stabilized in seven of 11 patients (64%) with mild sensorimotor neuropathy (walking unaided) and in two of the eight patients (25%) with severe sensorimotor deficit (walking with aid) at liver transplantation. In five other patients, deterioration of motor deficit occurred only within the first year after liver transplantation, but was progressive after this interval in two patients. None of the six patients with pure sensory neuropathy developed motor loss and superficial sensory loss remained unchanged. Two years after liver transplantation, the rate of myelinated axon loss in nerve biopsy specimens was markedly lower in seven transplanted patients (0.9/mm(2) of endoneurial area/month) than in non-transplanted patients (70/mm(2) of endoneurial area/month). Symptoms of dysautonomia and quantitated cardiocirculatory autonomic tests remained unchanged. In all patients, serum mutated TTR decreased to 2.5% of pre-liver transplantation values and remained at this level during follow-up. We presently recommend liver transplantation in FAP patients at onset of first symptoms and exclusion of those with a Norris score below 55 and/or with urinary incontinence.

Action Potentials↗
PubMed2000

Real-time volumetric echocardiography: the technology and the possibilities.

The heart is a dynamic organ with complexities in its shape. As such, it places special demands on three-dimensional techniques for reconstruction. Real-time volumetric echocardiography, which is based on phased array and parallel processing principles to enhance line density within a scan volume, provides rapid image acquisition. We introduce the principle, potential clinical importance, current limitations, and future of volumetric imaging methods.

Echocardiography, Three-Dimensional↗
PubMed2000

Construct validity and predictive value of the Hooper Visual Organization Test in stroke rehabilitation.

The Hooper Visual Organization Test (HVOT; Hooper, 1958) is a commonly used measure of visual perceptual function. However, serious questions have recently been raised about its construct validity (i.e., the role of object naming). This study further examined the HVOT's construct validity and began exploring its contribution to outcome prediction in stroke rehabilitation. Participants were 101 rehabilitation inpatients suffering from recent cerebrovascular accidents. Each participant was administered the HVOT as part of a comprehensive neuropsychological evaluation. Wechsler Adult Intelligence Scale-Revised (Wechsler, 1981) Object Assembly, Picture Completion, and Cognistat Naming were significantly and uniquely correlated with the HVOT and accounted for about 45% of its variance. The HVOT's value in outcome prediction was examined by correlating HVOT with admission and discharge Functional Independence Measure (FIM; Granger & Hamilton, 1990; Hamilton, Granger, Sherwin, Zielezny, & Tashman, 1987) scores. While correlating weakly with some FIM domains, when admission FIM was controlled, the relation between HVOT and discharge FIM became nonsignificant. Implications of these data for the HVOT's clinical utility are discussed.

Aged↗
PubMed2000

[Familial amyloid polyneuropathy type I complicated by chronic glaucoma: 3 cases].

PURPOSE: We report 3 cases of familial amyloid polyneuropathy type I (FAP) with amyloid infiltration of the vitreum and glaucoma. PATIENTS AND METHODS: We reviewed the records of three patients, 2 females and one male, aged 41, 47 and 83 years respectively. The 3 patients had familial amyloid polyneuropathy type I with vitreous infiltration and open angle glaucoma. The two women underwent a liver graft four years earlier. Vitrectomy allowed confirmation of the diagnosis in the 83-year-old patient. Two patients underwent trabeculectomy, histological analysis of the iris and the trabeculum was obtained for one patient. RESULTS: The tree patients presented a polyneuropathy, vitreous infiltration and open angle glaucoma. Results of light microscopy of the iris and the trabeculum showed amyloid deposits in the iris and the trabecular meshworks. CONCLUSION: Familial amyloid polyneuropathy is a hereditary disease which may have a wide range of ocular manifestations. Glaucoma is among the most serious complications of familial amyloid polyneuropathy.

Adult↗
PubMed1999

Three-dimensional model of the ligand binding domain of the nuclear receptor for 1alpha,25-dihydroxy-vitamin D(3).

A three-dimensional model for residues 142-427 of the ligand binding domain (LBD) of the human nuclear receptor for 1alpha, 25-dihydroxy-vitamin D(3) [VDR] has been generated based on the X-ray crystallographic atomic coordinates of the LBD of the rat alpha1 thyroid receptor (TR). The VDR LBD model is an elongated globular shape comprised of an antiparallel alpha-helical triple sandwich topology, made up of 12 alpha-helical elements linked by short loop structures; collectively these structural features are similar to the characteristic secondary and tertiary structures for six nuclear receptors with known X-ray structures. The model has been used to describe the interaction of the conformationally flexible natural hormone, 1alpha,25-dihydroxy-vitamin D(3) [1alpha, 25(OH)(2)D(3)], and a number of related analogs with the VDR LBD. The optimal orientation of the 1alpha,25(OH)(2)D(3) in the LBD is with its A-ring directed towards the interior and its flexible side chain pointing towards and interacting with helix-12, site of the activation function-2 domain (AF-2) of the VDR. Mapping of four natural and one experimental point mutations of the VDR LBD, which result in ligand-related receptor dysfunction, indicates the close proximity of these amino acids to the bound ligand.

Amino Acid Sequence↗