PubMed Health⌕ Search

Biomedical subjects

I I Pipinos

Publications and source records attributed to I I Pipinos.

15 recordsLinked to original sources
PubMed2001

Analysis of coagulation changes associated with supraceliac aortic crossclamping using thromboelastography.

INTRODUCTION: The etiology of the coagulation changes seen with supraceliac (SC) aortic crossclamping (AXC) remains controversial; both primary fibrinolysis and clotting factor consumption have been implicated. The cause of these changes was investigated with thromboelastography (TEG), a test that measures the viscoelastic properties of thrombus to dynamically assess coagulation and fibrinolysis. METHODS: Eight pigs underwent SC AXC for 30 min; 5 pigs undergoing 30 min of infrarenal (IR) aortic clamping served as controls. Blood was drawn before AXC, before unclamping, and 5 and 60 min after unclamping. Thromboelastography and standard coagulation tests [prothrombin time (PT), partial thromboplastin time (PTT), fibrinogen, and platelet count] were performed. Measured TEG parameters included fibrinolytic index (a measure of fibrinolysis), r value (a reflection of intrinsic coagulation cascade activity), and the alpha angle and K values (measures of the speed of solid clot formation). Repeated measures ANOVA and t test were used for statistical analysis. RESULTS: There was no difference in the fibrinolytic index at any time point between the two groups. Increased activity of the intrinsic coagulation cascade during SC clamping was reflected by a lower R value just before unclamping (12.6 +/- 3.0 vs 20.0 +/- 3.0, P = 0.048) compared to IR AXC. Decreased speed of solid clot formation was noted 5 min after unclamping in the SC group but not the IR group [as defined by an increased K value (ANOVA, P = 0.010) and a decreased alpha angle value (ANOVA, P = 0.005)]. Fibrinogen levels were lower in the SC than in the IR group 5 (P = 0.013) and 60 min after unclamping (P = 0.02), but PT, PTT, and platelets did not differ between the groups at any time points. CONCLUSIONS: Thirty minutes of SC AXC does not result in fibrinolysis. There is increased clotting activity during SC clamping followed by decreased speed of clot formation and decreased fibrinogen levels after unclamping. These changes are consistent with clotting factor consumption.

Animals↗
PubMed2001

Factors affecting outcome in proximal abdominal aortic aneurysm repair.

Sixty-five consecutive patients undergoing nonemergent repair of an abdominal aortic aneurysm (AAA) originating above the visceral and/or renal arteries were studied to determine operative results and identify factors influencing outcome of proximal AAA repair. Factors associated with postoperative morbidity were analyzed using multivariate analysis. There were no postoperative deaths, paraplegia/paraparesis, or symptomatic visceral ischemia. Proximal AAA repair can be accomplished with acceptable mortality. If renal artery bypass or reimplantation is anticipated, cold renal perfusion may protect against renal dysfunction. Postoperative pulmonary dysfunction can be reduced by avoiding radial division of the diaphragm.

Adult↗
PubMed2000

Phosphorus 31 nuclear magnetic resonance spectroscopy suggests a mitochondrial defect in claudicating skeletal muscle.

OBJECTIVE: Decreased oxygen supply is generally accepted as the primary cause of muscle dysfunction in patients with peripheral arterial occlusive disease (PAOD) and intermittent claudication, although reported morphologic changes in the mitochondria of claudicating muscle suggest that impaired energy utilization may also play a role. With the measurement of the phosphate-rich compounds of muscle energy metabolism (adenosinetriphosphate [ATP], adenosinediphosphate [ADP], and phosphocreatine [PCr]) and pH, phosphorus P 31 magnetic resonance spectroscopy ((31)P MRS) provides a unique, noninvasive method to investigate this hypothesis further. METHODS: Calf muscle bioenergetics were studied in 12 men with moderate claudication (ankle-brachial index >/=0.5 and </=0.8) and 14 normal control subjects with the use of (31)P MRS and standard treadmill testing. Phosphorus MRS evaluation of the superficial posterior calf muscles was carried out with a 90-second submaximal isometric plantar flexion exercise. This mild exercise was chosen to permit in-magnet testing and to allow study of intrinsic mitochondrial efficiency under conditions of unchallenged blood flow. Phosphocreatine and ADP recovery time constants (t.c.), two very sensitive measures of oxidative mitochondrial function, as well as intracellular pH and ATP production via anaerobic glycolysis were determined during three exercise sessions and the results averaged and compared to known values obtained from a control population. RESULTS: During the (31)P MRS protocol, the end exercise intracellular pH (7.11 +/- 0.01 vs 7.11 +/- 0.01) and ATP production by anaerobic glycolysis (0.13 +/- 0.05 vs 0.14 +/- 0.03 mmol/L per second) were no different in PAOD patients versus control subjects, confirming that the protocol exercise did not significantly reduce oxygen supply. Phosphocreatine and ADP recovery t.c. (137 +/- 41 vs 44 +/- 3 seconds and 60 +/- 10 vs 29 +/- 2 seconds, respectively) were significantly slower than normal (P <.05, t test). There was, however, no correlation between these measures of mitochondrial function and any treadmill parameter (P >.5, Pearson moment correlation). CONCLUSIONS: Phosphorus 31 MRS provides the first direct evidence of defective energy metabolism in the mitochondria of claudicating calf muscle. This defect appears to be independent of both arterial flow and the severity of occlusive disease in patients with mild to moderate claudication. Coupled with documented ultrastructural and DNA abnormalities in the mitochondria of claudicating skeletal muscle, these data provide evidence for a secondary cause of muscle dysfunction in intermittent claudication.

Adenosine Diphosphate↗
PubMed2000

Lymphoepithelial cyst in the pancreas: a case report and review of the literature.

BACKGROUND: Lymphoepithelial cysts of the pancreas constitute a rare clinicopathologic entity. CASE REPORT: We report a case of lymphoepithelial cyst of the pancreas and review the world literature. RESULTS: Lymphoepithelial cysts are true pancreatic cysts lined by squamous epithelium and surrounded by mature lymphoid tissue. The cyst arises typically in middle aged men, and is usually asymptomatic or causes nonspecific abdominal complaints. There is no specific serologic marker for this entity. None of its radiologic characteristics can help differentiate it from other cystic lesions of the pancreas. Fine-needle aspiration cytology may be able to suggest its benign nature and identify it as a true cyst of the pancreas. The outcome after surgical excision is uniformly good with good symptom control and no recurrences. RECOMMENDATIONS: In the symptomatic patient or the asymptomatic patient with acceptable surgical risk a simple cyst excision should be performed after verification of the diagnosis with frozen section. In the asymptomatic patient with a high surgical risk, in whom fine-needle aspiration suggests the diagnosis of a lymphoepithelial cyst, observation of the lesion is recommended. When simple cyst excision is technically not possible, extensive resections/reconstructions should be avoided and drainage/bypass procedures may be considered.

Adult↗
PubMed2000

Retrograde jejunogastric intussusception.

Retrograde gastrointestinal intussusception is a rare entity, most commonly reported after gastric resection and gastrojejunostomy. Its occurrence in the absence of previous gastric resection is extremely unusual, with only four cases reported. All cases were associated with previously placed gastrostomy tubes and implicated these as the inciting factor. We present a fifth case and review the literature. The mechanism of this phenomenon is described and recommendations to prevent this potentially fatal complication are made.

Aged↗
PubMed1999

31P MRS studies of exercising human muscle at high temporal resolution.

Methods for measuring mitochondrial activity from 31P magnetic resonance spectroscopy data collected during and after exercise were compared in controls, weight lifters, and peripheral vascular occlusive disease (PVOD) patients. There were trends toward increasing mitochondrial activity during exercise in order from PVOD patients, moderately active controls, highly active controls, to weight lifters. Results from PVOD patients show divergence of some measures due to 1) the non-exponential nature of phosphocreatine recovery, and 2) potential breakdown of [ADP] control of the mitochondria due to lack of oxygen (for Qmax calculation). These results demonstrate the utility of obtaining and directly analyzing high time resolution data rather than assuming monoexponential behavior of metabolite recovery.

Adenosine Diphosphate↗
PubMed1998

Response to angiotensin inhibition in rats with sustained renovascular hypertension correlates with response to removing renal artery stenosis.

PURPOSE: Sustained (late-phase) renovascular hypertension is associated with lower plasma renin activity than is the early phase. It is not clear to what extent this reduced plasma renin activity reflects diminished influence of the renin-angiotensin system. It also is not clear whether this change in the character of the disease influences the effectiveness of surgical removal of the renal artery stenosis in reversing hypertension. Using an animal model of sustained (> or =10 weeks after renal artery clipping) two-kidney, one-clip renovascular hypertension, we hypothesized that the magnitude of the depressor response to selective angiotensin II receptor blockade with losartan would reflect the influence of the renin-angiotensin system on hypertension and enable us to predict the depressor response to subsequent surgical removal of the clip. METHODS: The left renal arteries of 20 male Sprague-Dawley rats weighing 150 to 200 gm were fitted with a silver clip (0.23 mm internal diameter). Systolic blood pressure was measured by means of tail-cuff plethysmography for 10 weeks. Rats were then given losartan orally (30 mg/kg a day) for 1 week while blood pressure was monitored. After an additional week to allow recovery, 13 rats underwent surgical unclipping, and seven underwent sham repair. Blood pressure again was monitored over the final week. RESULTS: All two-kidney one-clip rats had hypertension 10 weeks after clipping (mean systolic blood pressure 206 +/- 10 mm Hg). Losartan decreased systolic blood pressure by 36 +/- 6 mm Hg. The response was variable, ranging from 3 to 66 mm Hg, and overall blood pressure did not normalize (170 +/- 8 mm Hg). Subsequent surgical unclipping decreased systolic blood pressure by 46 +/- 9 mm Hg. Again the response was variable, ranging from 10 to 99 mm Hg, although overall blood pressure did not normalize (164 +/- 7 mm Hg). The decrease in blood pressure after unclipping showed a high correlation with the blood pressure decrease after losartan administration (r = 0.861, p < 0.001). Resting plasma renin activity (before intervention) was 16 +/- 4 ng angiotensin I per milliliter per hour and was not predictive of the response to either losartan or surgical unclipping. The rats subjected to sham operations had no statistically significant changes in blood pressure. Histologic evaluation showed patent renal arteries without appreciable stenosis or intimal hyperplasia after removal of the clips. CONCLUSIONS: In sustained two-kidney, one-clip renovascular hypertension, the depressor response to angiotensin II receptor blockade is attenuated, suggesting that late-phase hypertension becomes increasingly angiotensin II-independent. In our model, the extent to which sustained renovascular hypertension becomes refractory to 7 days of angiotensin II blockade is highly predictive of the ultimate outcome of surgical repair of renal artery stenosis.

Angiotensin Receptor Antagonists↗
PubMed1998

Superficial temporal artery aneurysms.

OBJECTIVE: We analyzed the data from our vascular registry to determine the cause, clinical features, and cost-effective management of this uncommon pathologic entity. DESIGN: Patients referred to the vascular surgery outpatient clinic of a tertiary referral center during the past 18 years were evaluated. SUBJECTS: The subjects were six male patients (14 to 32 years) referred for evaluation of a unilateral pulsatile mass over the temporal region of the head. INTERVENTION: Diagnosis of superficial temporal artery aneurysm was verified by loss of the aneurysm's pulse with compression of the ipsilateral proximal superficial temporal artery. All treated aneurysms were electively ligated and excised as an ambulatory procedure. RESULTS: The symptoms were resolved. No recurrences or other complications were seen. CONCLUSIONS: Although rare, a superficial temporal artery aneurysm should be considered when a temporal head mass is evaluated. This condition is almost always a result of blunt or penetrating head trauma. Clinical examination is sufficient to confirm the diagnosis. Simple elective ligation and excision of the aneurysm is curative.

Adolescent↗
PubMed1997

Secondary aortoesophageal fistula.

Secondary aortoesophageal fistula is the rarest type of aortopeptic fistula, characterized by communication between the reconstructed aorta and the esophagus. This condition has been reported to be uniformly fatal, even after prompt diagnosis and treatment. We report what may be the first case of a successfully managed secondary aortoesophageal fistula that occurred 14 months after repair of a Crawford type II thoracoabdominal aortic aneurysm. The entity was diagnosed with a combination of esophagogastroduodenoscopy and aortography. At exploration, a communication between the proximal anastomosis and the esophagus with otherwise minimal mediastinal contamination was encountered. The anastomosis was replaced with an interposition polytetrafluoroethylene graft, and the esophageal defect was debrided, primarily closed, and reinforced with adjacent old aneurysm wall. There were no postoperative complications, and the patient remains well 18 months after fistula repair.

Aged↗