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D J Effeney

Publications and source records attributed to D J Effeney.

At least 37 records · Page 2Linked to original sources
PubMed1988

Creation of a carotid-jugular fistula for repeated hemoaccess in a canine model.

We have developed a method to obtain access to the arterial circulation in the dog, which can be used for repeated hemoperfusion, hemodialysis, and for pharmacokinetic studies. Hemoaccess is achieved by the surgical creation of a carotid-jugular fistula. Using the fistula, which is internal and autogenous, has overcome the problems of thrombosis, dislodgement, and infection, which are associated with external shunts. Blood flow rates of between 70 and 100 ml/min in 12-kg dogs were obtained through a hemodialysis pump. The surgical techniques are described in detail so that other investigators can avail themselves of the methodology.

Animals↗
PubMed1988

Femoral false aneurysms: a recommendation for the method of repair.

False aneurysm formation is a major complication of vascular surgery. The most frequent site of anastomotic false aneurysm formation is the femoral artery. Between January 1974 and June 1986, 26 patients with 42 femoral false aneurysms were treated at the Princess Alexandra Hospital. Aneurysms developed following Dacron arterial grafting (29 aneurysms), saphenous vein grafting (10 aneurysms), umbilical vein grafting (one aneurysm) and femoral embolectomy (two aneurysms). Arterial wall failure (with intact suture and graft) was the most frequent operative finding. Ten recurrent aneurysms developed. There was a significantly greater number of recurrences when resuture or patch repair was employed than when an interposition graft was used as a repair. The development of a femoral anastomotic false aneurysm should be viewed as a total failure of that anastomosis and repair should be by replacement with an interposition graft rather than repair of the failed anastomosis by suture or patch.

Anastomosis, Surgical↗
PubMed1988

Nonlinear intestinal first-pass metabolism of salicylamide in dogs after portacaval transposition.

The dose-dependent first-pass metabolism and pharmacokinetics of salicylamide (SAM) were studied at four dose levels in dogs before and after portacaval transposition. Four minutes after each p.o. dose, a tracer dose of [14C]SAM was given i.v. to determine clearance and bioavailability. Over the dosage range studied pretransposition, 5 to 40 mg/kg, bioavailability increased from 0.24 +/- 0.14 (mean +/- S.D.) to 0.76 +/- 0.20 (P less than .05). Clearance decreased from 3.4 +/- 1.0 to 0.6 +/- 0.11 liter/min (P less than .01) and half-life increased from 5.0 +/- 1.2 to 23.5 +/- 6.1 min (P less than .01). Over the dosage range studied post-transposition, 1.5 to 20 mg/kg, bioavailability increased from 0.31 +/- 0.09 to 0.99 +/- 0.08. Clearance and half-life had the same values and showed the same dose-dependence as in the normal dogs. The amount of SAM removed by the intestine during first-pass remained constant at about 1 mg/kg over the dose range given to the post-transposition animals. Therefore, although more easily saturable than the liver, the intestine plays an important role in first-pass metabolism of low p.o. doses of SAM. In contrast to previous results in the normal dog, the p.o. coadministration of sodium sulfate did not reduce the bioavailability of SAM in transposed dogs. This indicates that the nonlinear intestinal first-pass metabolism of SAM is not due to the depletion of the cosubstrate precursor, inorganic sulfate.

Administration, Oral↗
PubMed1987

Concurrent intravenous administration of a labeled tracer to determine the oral bioavailability of a drug exhibiting Michaelis-Menten metabolism.

The theoretical accuracy of concurrent administration of labeled intravenous tracer and oral doses to estimate the bioavailability of drugs exhibiting Michaelis-Menten kinetics was determined by computer simulation. The simulation model consisted of sampling and hepatic compartments with elimination occurring by hepatic metabolism according to the venous equilibration model. The relationships between error in bioavailability estimation and dose, metabolic activity (Vmax), first-order absorption rate constant (ka), and volume of distribution (V) and the fraction of the dose absorbed were examined. Error was hypothesized to be relatively low when conditions result in a relatively constant value of clearance after oral dosing or when the concentration-time curves after intravenous and oral dosing are similar. The results were consistent with these hypotheses and, under most conditions, error was less than 15%. The effects, on error, of altering the intravenous tracer dose input and having a lag time in absorption of drug from the oral dose were also determined. In general, accuracy was improved by delaying administration of the iv tracer for a time equal to 50% of the oral dose peak time or by administering the tracer dose by constant-rate infusion from the time of oral dosing to the peak time. Lag time in absorption of the oral dose was shown to often result in overestimates in bioavailability of greater than 50%.

Administration, Oral↗
PubMed1987

Caecal volvulus: ten year experience in an Australian teaching hospital.

Sixteen cases of caecal volvulus were treated surgically at a major Australian teaching hospital over a decade. Review of these cases suggests that this condition may be more common in fit people between 30 and 40 years of age than in the elderly or institutionalised. Caecal volvulus was more common in women than in men, possibly because adhesions from previous gynaecological surgery may initiate volvulus. In some other cases colonic distension due to poor muscle tone rather than distal obstruction may have been an important predisposing factor. Preoperative diagnosis was not usually made, but might have been facilitated if knowledge of the above predisposing factors had been available. This would allow colonoscopic reduction to be considered as a therapeutic alternative to laparotomy. At laparotomy, right hemicolectomy or caecal fixation (caecostomy or caecopexy) were the alternative methods of treatment.

Adult↗
PubMed1987

Prostacyclin production by the heart: effect of nicotine and carbon monoxide.

Smoking has been linked to the development and progression of atherosclerosis but the mechanism by which smoking exerts its deleterious effects remains unknown. This study was designed to examine in a systematic way the effects of nicotine and carbon monoxide on platelets, arterial walls, and the heart. Results of experiments designed to assess the effect of nicotine and carbon monoxide on the production of prostacyclin (PGI2) by the rabbit heart are reported. Animals exposed to carbon monoxide had the carboxyhemoglobin raised to at least 12% by breathing an atmosphere enriched with carbon monoxide. Nicotine was infused at 50 micrograms/kg/hr for 1 week. Nicotine was measured by gas/liquid chromatography. PGI2 was measured by radioimmunoassay of 6-keto-PGF1 alpha, and its biologic activity was assessed by inhibition of platelet aggregation. Nicotine is concentrated in the heart and blood vessel wall and causes a statistically significant reduction in PGI2 production. Carbon monoxide raised PGI2 production significantly in all chambers, and the combination of nicotine and carbon monoxide further raised PGI2 production. The difference between the effects of nitrogen and carbon monoxide alone and nitrogen and a combination of nitrogen and carbon monoxide was significant in all chambers. It is hypothesized that nicotine exerts a direct metabolic effect in lowering PGI2 production. Carbon monoxide may make the endothelial cell relatively hypoxic, a powerful stimulus of PGI2 production, or less likely exert a direct toxic effect on the endothelial cell.

6-Ketoprostaglandin F1 alpha↗
PubMed1986

Extrahepatic extraction of salicylamide in dogs.

Extrahepatic conjugation may be an important mechanism for the metabolism of many phenolic compounds. We have observed dose-dependent sulfoconjugation of salicylamide (SAM) in the lung, kidney and forelimb of dogs during steady-state infusions. The lungs alone accounted for more than one-half the total elimination at the lowest infusion rate (0.3 microgram/min/kg). The limbs appeared to play an important secondary role in SAM elimination whereas the kidneys made only a minor contribution to total elimination. At the highest infusion rate (500 micrograms/min/kg), extrahepatic extraction approached zero and elimination by the three extrahepatic sites fell to less than 31% of total elimination. Dose-dependent elimination at the three extrahepatic sites was responsible for most of the dose dependence observed in these studies. Extrahepatic extraction was insensitive to plasma inorganic sulfate. Clearance significantly, but only slightly, increased on coinfusing sodium sulfate at a rate that increased plasma inorganic sulfate from one-sixth (after depletion by SAM infusion) to two times normal.

Animals↗
PubMed1985

Sonography of axillofemoral and femorofemoral subcutaneous arterial bypass grafts.

Axillofemoral and femorofemoral grafts in 12 patients were examined on 22 occasions with linear-array and digital static scanners with 5-MHz transducers and a 10-MHz high-resolution real-time instrument. Real-time instruments that produce a linear image, particularly high-resolution small-parts units, are the most appropriate to define the incorporation of the prosthesis, its pulsatility, and the nature of the perigraft bed. Early after implantation, these grafts have small perigraft fluid collections in the surgically created tunnels. These collections disappear spontaneously as the graft is incorporated into the tissues. However, discrete and persistent perigraft fluid collections are abnormal. Such collections were noted in five patients. One proved to be abscess and four were seromas. Graft occlusions (four patients) and an anastomotic aneurysm (one patient) were also readily diagnosed on sonography.

Aged↗
PubMed1985

Prescription options for the below knee amputee. A review.

In 1973 a workshop sponsored by the National Academy of Sciences recommended that "efforts to develop prescription criteria for use of the numerous variants of the BK prosthesis should be intensified." This paper provides a review of the important considerations in the prescription of a below-knee prosthesis. It is intended that this information would assist the physician to make better informed decisions regarding the specific type of prosthesis for a particular patient. No attempt has been made to describe all prosthetic options since a majority of amputees are fit with only a few prescriptions. Thus, socket design, suspension, shank type, and foot specification may be optimized for individual patients through mutual agreement of the prosthetist and the knowledgeable physician. This paper will present some of the more difficult prescription solutions to the various fitting problems that are representative of our nation's amputee population. This is done with the knowledge that there may be other and equally successful solutions to these problems. Several illustrative examples are provided.

Adult↗
PubMed1985

Static load response of the heels of SACH feet.

Excessive heel hardness in the prosthetic foot is a frequent problem that may contribute to decreased function in the above knee and below knee amputee. Optimal mechanical characteristics of the SACH (solid ankle cushion heel) foot have not been defined. In an effort to characterize the mechanical properties of the heels of these feet, we performed static load-deformation tests on the heels of SACH feet at stimulated heelstrike. These data were interpreted using least squares fitting of the natural logarithms of the load-deformation data. Statistical comparison of these data revealed no significant difference in the static response of the "medium" and "regular" grades of foot. A difference at the 1% level of confidence was found between the "soft" grade and the two firmer grades. Consistency within a grade of foot was quite good. Comparison of feet from another manufacturer revealed no difference in static response, suggesting consistency in static performance among manufactures. It was our clinical impression that all grades of SACH heels are too stiff.

Artificial Limbs↗
PubMed1985

Septic endarteritis after percutaneous transluminal angioplasty.

A case of septic endarteritis leading to septic arthritis and septic emboli occurred after percutaneous transluminal angioplasty. To our knowledge, this is the first reported instance of arterial wall infection potentially caused by percutaneous transluminal angioplasty. Treatment consisted of long-term intravenous antibiotics and drainage of the septic joint.

Angioplasty, Balloon↗
PubMed1985

Gait analysis in amputees.

There are marked differences from normal in both AK and BK gait. Forward velocity of walking is significantly lower in the amputee and is lower in the AK than in the BK subjects. Traumatic AK amputees ambulate with time-distance parameters of velocity, cadence, stride length and gait cycle which are all two standard deviations below normal. The same parameters for the traumatic BK amputee are only one standard deviation below normal. The symmetry of walking seen in the normal subject is not present in the lower extremity amputee. Measurements of single limb support times and motion analysis of the lower extremities as well as of the head, arms and trunk bear this out. This asymmetry of motion increases the excursion of the center of mass during each cycle and thereby increases the energy cost of ambulation. Energy cost of amputee gait often places the dysvascular AK amputee at his limits and strains other amputees severely. Further research is necessary to enable amputees to approach the walking capabilities of normal people.

Adult↗
PubMed1985

Prostacyclin production in regions of arterial stenosis.

The effect of abnormal flow dynamics on prostacyclin (PGI2) production by intact endothelium is unknown. To investigate this we studied the effects of graded stenoses on vessel wall PGI2 production in dogs (n = 8) whose femoral and carotid arteries (n = 32) were narrowed by machine-milled clips, producing 1.0 cm segmental stenoses of 25%, 50%, 75%, and 90% diameter reduction. Three dogs were injected with Indium 111-labeled platelets and 12 vessels were scanned for platelet deposition. All stenotic vessels were excised at 6 weeks for histologic study (hematoxylin-eosin section and immunohistochemistry for factor VIII) and PGI2 radioimmunoassay (as the metabolite 6-keto PGF1 alpha). All vessels remained patent with no thrombus formation in any segment. Vessel imaging in platelet-labeled animals showed no significant deposition. Histologic analysis demonstrated an intact endothelial surface in the stenotic segments, confirmed by the demonstration of factor VIII production by these cells. PGI2 production (per unit surface area) by the arterial segments with greater than or equal to 50% stenosis markedly exceeded the PGI2 production by the normal proximal and distal segments (p less than 0.0002) and showed further significantly increased production with increasing degrees of stenosis (p less than 0.00001). The data indicate increased PGI2 production by normal endothelium in regions of arterial stenosis. The mechanism of this increase is unknown, but this endothelial "turn on" effect may serve to inhibit deposition of platelets and thrombus formation in the presence of disordered flow patterns.

Animals↗
PubMed1985

Dose-dependent sulfoconjugation of salicylamide in dogs: effect of sulfate depletion or administration.

The effects of plasma inorganic sulfate concentrations on the dose-dependent kinetics of salicylamide (SAM) were examined in the dog. Decreasing plasma sulfate concentrations from 0.9 mM to less than 0.3 mM significantly decreased clearance of a small dose of SAM (5 mg/kg) to the sulfate conjugate. Infusing sodium sulfate to prevent the decrease in plasma inorganic sulfate concentration that follows a p.o. 20-mg/kg dose of SAM did not increase SAM elimination. However, sodium sulfate given p.o. decreased SAM bioavailability, which suggests a local effect of sulfate on intestinal first-pass metabolism of SAM. These data show some dependence of SAM metabolism on plasma inorganic sulfate concentrations, but only when they are markedly reduced.

Animals↗
PubMed1985

Spontaneous dissection of the superior mesenteric artery.

A patient presented with chronic visceral ischemia caused by spontaneous dissection of the superior mesenteric artery; this was treated successfully by "intimectomy" and patch angioplasty. Operative rather than expectant management is recommended for this rare but surgically accessible lesion.

Aortic Dissection↗
PubMed1985

Carotid endarterectomy in a metropolitan community: comparison of results from three institutions.

The hospitalizations of 300 patients who had carotid endarterectomies (CEA) in three different kinds of hospital were analyzed. 100 patients had CEA performed by experienced vascular surgeons in a university hospital (UH), 100 patients had CEA performed by experienced vascular surgeons in private community hospitals (PCH), and 100 patients had CEA performed by senior general surgery residents (GSR) assisted by experienced vascular surgeons in a university-affiliated Veterans Administration hospital (VA). Analysis of patient characteristics revealed that, compared with the other groups, VA patients were (1) younger (62 +/- 7 years; p less than 0.001); (2) had a higher frequency of peripheral vascular operations (51%; p less than 0.01; (3) were more often cigarette smokers (84%; p less than 0.001); and (4) had more contralateral carotid occlusions (19%) and ulcerated lesions (73%) (p less than 0.01). GSR had longer operating room times and cerebral ischemia times during shunt insertion and removal (6 +/- 2.8 minutes) and during the CEA (30 +/- 27 minutes) (p less than 0.001). Postoperative hypertension and neck hematomas were less common in PCH patients (p less than 0.001) than in the other groups. Although their duration of hospitalization (17 +/- 12 days) was longer, the VA patients experienced no increased morbidity. There was a high rate of cranial nerve injury in all groups (27%, 15%, 17%) but symptoms were not often permanent (9%, 6%, 6%). Our data indicate that results of vascular operations performed by well-supervised residents are comparable in all important respects to those performed by fully trained surgeons.

Aged↗
PubMed1984

Symptomatic extrinsic compression of the cervical carotid artery.

A 41-year-old man had external compression of the internal carotid artery. He had hemispheric symptoms brought on by flexion of the neck and turning his head to the left. The compression was diagnosed by positional angiography. Treatment consisted of excision of the posterior belly of the digastric muscle and associated fascial bands.

Adult↗