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Biomedical subjects

J P Hurley

Publications and source records attributed to J P Hurley.

At least 19 recordsLinked to original sources
PubMed2001

Partitioning of total mercury and methylmercury to the colloidal phase in freshwaters.

Using tangential flow ultrafiltration, total mercury (HgT) and methylmercury (MeHg) concentrations in the colloidal phase (0.4 microm-10 kDa) were determined for 15 freshwaters located in the upper Midwest (Minnesota, Michigan, and Wisconsin) and the Southern United States (Georgia and Florida). Unfiltered concentrations were typical of those reported for freshwater and ranged from 0.9 to 27.1 ng L(-1) HgT and from 0.08 to 0.86 ng L(-1) MeHg. For some rivers, HgT and MeHg in the colloidal phase comprised up to 72% of the respective unfiltered concentration. On average, however, HgT and MeHg concentrations were evenly distributed between the particulate (>0.4 microm), colloidal, and dissolved (<10 kDa) phases. The pool of Hg in the colloidal phase decreased with increasing specific conductance. Results from experiments on freshwaters with artificially elevated specific conductance suggest that HgT and MeHg may partition to different subfractions of colloidal material. The colloidal-phase HgT correlation with filtered organic carbon (OC(F)) was generally poor (r2 < 0.14; p > 0.07), but the regression of MeHg with OC(F) was strong, especially in the upper Midwest (r2 = 0.78; p < 0.01). On a mass basis, colloidal-phase Hg concentrations were similar to those of unimpacted sediments in the Midwest. Mercury to carbon ratios averaged 352 pg of HgT/mg of C and 25 pg of MeHg/mg of C and were not correlated to ionic strength. The log of the partition coefficient (log K(D)) for HgT and MeHg ranged from 3.7 to 6.4 and was typical of freshwater values determined using a 0.4 microm cutoff between the particulate phase and the dissolved phase. Log K(D) calculated using the <10 kDa fraction as "dissolved" ranged from 4.3 to 6.6 and had a smaller standard deviation about the mean. In addition, our data support the "particle concentration effect" (PCE) hypothesis that the association of Hg with colloids in the filter-passing fraction can lower the observed log K(D). The similarity between colloidal and particulate-phase partition coefficients suggests that colloidal mass and not preferential colloidal partitioning drives the PCE.

Carbon↗
PubMed1997

Surgical relief of tracheobronchial obstruction in infants and children.

OBJECTIVE: Congenital tracheobronchial obstruction (TBO) presents a complex problem both in terms of diverse aetiology, presence of associated anomalies and the operative strategy to be adopted. We report a single centre experience in managing this difficult problem. METHODS: Twenty-four infants and children with TBO referred to our unit over a 12-year period are reviewed. Aetiology of TBO included vascular rings (n = 9), anomalous innominate artery (n = 6), congenital tracheal stenosis (n = 5), segmental bronchial stenosis (n = 2) and pulmonary artery compression of the main bronchi (n = 2). Seven patients had concurrent cardiac anomalies. Stridor was the commonest presenting symptom (67%). Mean delay from onset of symptoms to referral was 19 months. One patient died preoperatively due to acute airway obstruction. Mean age at operation was 33.1 +/- 42 months (range 4 days-156 months) and 11 children were under 1 year at the time of surgery. In cases of TBO secondary to vascular rings, division of the ring resulted in relief of symptoms in seven cases, with two requiring further surgery for resultant tracheomalacia. Four of the five patients having tracheal resection were operated on with the use of cardiopulmonary bypass; three of these patients had concurrent correction of cardiac lesions, with two survivors. Tracheobronchial anastomoses were carried out using continuous polydioxanone (PDS). Patients with anomalous innominate arteries required aortopexy in five and innominate artery suspension in one, while those with pulmonary artery compression of the main bronchi had correction of their intracardiac defects (n = 2). RESULTS: Hospital mortality was 8.7% and there has been one late death due to Eisenmenger syndrome secondary to pulmonary regurgitation, atrial septal defect (ASD) and patent ductus arteriosus (PDA). On follow-up (mean 40 +/- 31 months), 19 patients are alive and symptom free. There have been no anastomotic strictures following tracheobronchial resection. The single most important predictor of mortality was the presence of associated cardiac anomalies. CONCLUSIONS: TBO can be managed effectively by a single operation in both infants and children without a detrimental effect on tracheal growth. We advocate consideration of concurrent repair of the tracheal and cardiac lesions. Cardiopulmonary bypass (CPB) allows this concurrent correction of cardiac lesions and also facilitates tracheal resection.

Adolescent↗
PubMed1997

A malignant astrocytoma containing simian virus 40 DNA in a macaque infected with simian immunodeficiency virus.

Polyomaviruses have proven oncogenicity in nonhost experimental animals; however, studies concerning the association between human brain tumors and simian and human polyomaviruses have yielded inconclusive results. We examined the relationship of SV40 to a malignant astrocytoma found in the right frontal lobe of a pigtail macaque (Macaca nemestrina) infected with simian immunodeficiency virus (SIV). Consistent with the histologic diagnosis, the tumor was immunoreactive with antibodies to S-100 protein, vimentin, and glial fibrillary acidic protein, but negative for neurofilament protein, synaptophysin, neuron-specific enolase, and chromogranin A. At the time of SIV inoculation, the animal was seropositive for SV40. Polymerase chain reaction assay of tumor DNA, but not normal brain DNA, yielded a 300 base-pair fragment corresponding to the carboxy-terminal coding region (C-terminus) of the large T antigen gene of SV40, suggesting an association with the tumor.

Animals↗
PubMed1994

Retrospective analysis of the utility of video-assisted thoracic surgery in 100 consecutive procedures.

One hundred consecutive video-assisted thoracic surgery (VATS) procedures, diagnostic (n = 54) and therapeutic (n = 46), in 90 patients over a 2-year period are reviewed. Hospital mortality was 2%. Conversion to formal thoracotomy was required in 3%, and re-exploration for bleeding in 1%. Seven patients required intensive care unit facilities postoperatively. The technique described was safe and there was minimal postoperative morbidity. Diagnostic VATS was of particular use in cases of indeterminate pulmonary masses (Sensitivity of 96%), anterior mediastinal masses and in immunocompromised patients. Video-assisted thoracic surgery may now be the treatment of choice for recurrent pneumothoraces and it demonstrated potential for development in a variety of other benign thoracic disorders. This method had a limited role in the management of empyaema with a 60% conversion rate to formal thoracotomy. Pulmonary resections were feasible but its role in the treatment of malignancy is questioned.

Adolescent↗
PubMed1994

Imaged thoracoscopic surgery--patent ductus arteriosus ligation.

Video-assisted thoracic surgery (VATS) combines excellent visualization of the intrathoracic structures with a minimally invasive technique. A patient is presented who underwent successful ligation of a patent ductus arteriosus with a video-assisted thoracoscopic technique.

Adult↗
PubMed1994

Video-assisted thoracic surgery for delayed pericardial effusion post-CABG.

Delayed-onset pericardial effusion following coronary artery bypass grafts can give rise to significant morbidity in its presentation and in its management by traditional surgical techniques. A video-assisted thoracoscopic technique to create a pericardial window, with the advantage of a minimally invasive approach combined with excellent visualization in such a patient is described.

Coronary Artery Bypass↗
PubMed1994

Thoracoscopic assisted paraoesophageal hernia repair.

A video assisted thoracic surgical repair of a paraoesophageal hernia is described. The advantage of the procedure was the combination of the diagnostic and therapeutic facility characteristic of a transthoracic approach without exposing the patient to the morbidity of formal thoracotomy.

Aged↗
PubMed1993

Video assisted thoracic surgery.

Using video thoracoscopic techniques in 30 patients over a twelve month period we have been able to perform 33 procedures that would have been previously performed by thoracotomy, with its associated morbidity. We have found the applications of this procedure to be diverse, being both diagnostic (n = 16) and therapeutic (n = 17). The diagnostic procedures were associated with a high diagnostic yield and allowed accurate staging. The therapeutic procedures were associated with minimal morbidity and short hospital stay. Our experience indicates an established and expanding role for Video Assisted Thoracic Surgery.

Adolescent↗
PubMed1993

Isolated man-in-the-barrel syndrome following cardiac surgery.

A 59-year-old chronically hypertensive patient developed "man-in-the-barrel syndrome" following urgent coronary artery bypass graft surgery (CABG). This syndrome describes a brachial diplegia with intact motor function of the legs. Magnetic resonance imaging confirmed areas of ischaemia consistent with hypoperfusion leading to border-zone infarction between the territories of the anterior and middle cerebral arteries. The patient made a complete functional recovery.

Angina, Unstable↗
PubMed1991

A preventable cause of tracheal injury at oesophagectomy.

Advocates of transhiatal oesophagectomy warn of the danger of tracheal injury resulting from the blind dissection of tumours of the upper and middle thirds of the oesophagus when the tumour has invaded the membranous part of the trachea. We report an unusual cause of tracheal injury at transhiatal oesophagectomy due to dissection at the level of the inflated endotracheal cuff in a patient with a tumour at the gastro-oesophageal junction.

Aged↗
PubMed1990

Nitrate biosynthesis in rats, ferrets and humans. Precursor studies with L-arginine.

L-Arginine, the primary nitrogen source for nitric oxide synthesized by many cell types in culture and for biosynthesized nitrate in humans, is also a nitrogen source for biosynthesized nitrate in rats and ferrets. After administration of [15N2]L-arginine to rats and ferrets, [15N]NO3- was detected in urine. Escherichia coli lipopolysaccharide induced more than a 10-fold increase in urinary nitrate in rats and a parallel increase in incorporation of 15N from [15N2]L-arginine into NO3-. Bradykinin, a vasodilator which induces nitric oxide production by endothelial cells in vitro, lacked detectable effect on urinary nitrate or on incorporation of L-arginine nitrogen into nitrate in rats. A prolonged period of vasodilation brought on by an extended period of exercise increased urinary nitrate 2-fold in human subjects. In the rat, recoveries in 24 h post-dose urine collections of [15N]NO3- given i.v. and i.p. were 75 and 64% respectively, while in the ferret, recoveries of i.v. and per os [15N]NO3- doses were 49 and 34% respectively. Thus, nitrate synthesized by mammalian cells in vivo would undergo losses similar to those for exogenous nitrate.

Adult↗
PubMed1990

Transhiatal oesophagectomy--its role for tumours of the middle third of the intrathoracic oesophagus.

All patients presenting to a regional unit with oesophageal carcinoma over a twelve month period are reviewed and the role of transhiatal oesophagectomy for tumours of the middle third of the intrathoracic oesophagus is evaluated. Of the 28 cases of oesophageal carcinoma, 22 (78%) were resected by blunt transhiatal oesophagectomy, the remaining six (22%) has various forms of palliative treatment. In the resected group post-operative morbidity was compared in patients with tumours of the middle third to those with lower and upper third tumours combined. There was one post-operative death in each group giving an overall operative mortality of 9%. Resection for carcinoma of the middle third (N = 7) resulted in a complication rate of 50% and a mean ICU stay of 19.5 days as opposed to a complication rate of 35% and a mean ICU stay of ten days (P = 0.050) for tumours of upper and lower third combined (N = 15). On the basis of these figures we question whether transhiatal oesophagectomy, despite its many advantages, can be applied safely to tumours of the middle third of the intrathoracic oesophagus.

Aged↗
PubMed1988

Hemolymphangioma in a neonate--a therapeutic problem--case history.

The authors present the case of a one and one-half-day-old child with a 4 X 5 cm hemolymphangioma of the left lower extremity. The mass was a violaceous, protuberant, compressible tumor covered with distended peau d'orange skin. A pressure dressing was applied to the lesion, and it was made certain that the blood supply to the foot was not cut off. The lesion began to resolve within a week and over the next few months; however, pressure may need to be continued for her lifetime. The patient had been wearing a pressure-gradient leotard as of six months of age, but this was discontinued after two weeks because of the authors' inability to converse with the child to determine how much pressure could be safely employed. This is one example of a to date successfully treated hemolymphangioma in a neonate using a pressure dressing initially followed by combined compression therapy. The proposed mechanism of this therapy, as well as comparison with other types of therapy, is discussed.

Female↗
PubMed1986

Capture and detection of carcinoembryonic antigen on antibody coated beads used in enzyme immunoassay.

We have evaluated antibody coated beads for capture and detection of carcinoembryonic antigen (CEA). Assay parameters of time, temperature, buffer molarity, specificity of antibody on the bead and reagent addition sequence have been studied. Optimal assay kinetics occurred at a temperature of 45 degrees C and a buffer molarity of 0.1M or above. The type and quantity of antibody on the bead surface were also critical to optimal CEA detection. Beads coated with baboon or goat anti-CEA antibody were able to capture a higher percentage of CEA than monoclonal mouse anti-CEA antibody or guinea pig anti-CEA antibody. The sequence of addition of CEA, anti-CEA antibody coated bead, and anti-CEA-horse radish peroxidase conjugate was important for optimal CEA detection. Formation of an immune complex of CEA with the anti-CEA horse radish peroxidase conjugate prior to capture of the CEA on an antibody bead resulted in the optimal detection of CEA.

Animals↗
PubMed1986

Tinea nigra masquerading as acral lentiginous melanoma.

Tinea nigra is a superficial mycosis that may mimic serious pigmentary lesions. A lesion recently encountered on the foot was suspected of being a malignant melanoma. Histologic and mycologic studies, done after a biopsy was obtained, demonstrated Exophilia werneckii in the stratum corneum. Tinea nigra should be considered in the diagnosis of pigmented lesions of the hands and feet. A KOH examination is a simple and rapid means of demonstrating this entity.

Adult↗
PubMed1985

Energy of the oscillating legs of a fast-moving cheetah, pronghorn, jackrabbit, and elephant.

Lifelike models of the oscillating legs treated as three-segment systems show the course of kinetic and potential energy over the locomotor cycle for a cheetah, pronghorn, jackrabbit, and elephant running at speeds approaching their maxima. The models can be adjusted to eliminate differences among the animals in time intervals, mass or length of limb, and joint angles. This facilitates analysis of the influence on total energy of each of these variables and of the distribution of mass among leg segments. Fast-cycling legs of the carnivore type have significantly more energy than those of the hoofed type. This may contribute to the lesser endurance that is usual for carnivores that hunt using a high-speed dash.

Acinonyx↗