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Biomedical subjects

G D Pond

Publications and source records attributed to G D Pond.

At least 19 recordsLinked to original sources
PubMed1994

Catheter-directed urokinase thrombolysis: an adjunct to PTA/surgery for management of lower extremity thromboembolic disease.

Catheter-directed thrombolysis was used either alone or as an adjunct to percutaneous transluminal angioplasty (PTA) or surgery for peripheral vascular occlusion on 112 occasions in 102 patients. Symptom duration ranged from < one to > twenty-eight days. Thrombolytic therapy using urokinase plasminogen activator thrombolysis (uPAT), including intrathrombic injection when possible, was successful (> 50% lysis) in 99 procedures (88%). Technical failure (< 50% lysis) occurred in 13 procedures (12%). In 9 of the 13 failures, intrathrombic injection of urokinase was not possible, but the duration of occlusion was > twenty-eight days in all but 1. Two other failures were from embolic sources and 2 more occurred in patients with a hypercoagulable state. The uPAT was adjunctive to PTA/surgery in 56 cases (50%). PTA following uPAT was required and successfully performed in 24 of 27 cases (88.9%). Surgery followed lytic therapy in another 32 (including the 3 failed PTAs). In the remaining 56 cases (50%), no additional intervention was required. There were 20 complications (18%), minor in 16 of 20 (80%). Minor complications included small puncture site hematomas and distal embolization resolved by continued lytic therapy. Four major complications occurred. One was retroperitoneal hemorrhage directly contributing to the only death in the series. The other 3 were hematuria (2) and femoral neuropathy (1). The authors conclude that catheter-directed lytic therapy alone or as an adjunct to PTA/surgery is a valuable approach to peripheral vascular thromboembolic disease. It is less likely to succeed in chronic occlusion. The incidence of complications is moderate but acceptable.

Aged↗
PubMed1991

Proximity injuries: correlation with results of extremity arteriography.

The results of 170 emergency arteriography procedures in 142 patients who had sustained extremity injuries near major arteries were correlated with the findings from a physical examination conducted prior to arteriography. Radiographically demonstrable significant arterial injuries, which usually required surgical repair, were present at 42 of the 170 injury sites (25%). Major physical findings suggestive of arterial injury were noted at 105 of 170 sites (62%). Arteriography demonstrated a significant injury in 40 (38%) of these 105 injury sites, representing 95% of all major arterial injuries. Among the 65 injury sites without any suggestive major physical finding, only two were associated with a significant vascular injury at arteriography (3%) (5% of all 42 arterial injuries). At each of these 65 injury sites, the decision to perform emergency arteriography was based solely on the proximity of the wound to a major artery. In spite of this very low yield in the subgroup of 51 patients without major physical findings, emergency arteriography is still routinely requested for extremity injuries at the authors' institutions. The validity of this policy, a possible reason for its development, and its effect on patient disposition are examined.

Adolescent↗
PubMed1991

Cutaneous ulceration due to contrast extravasation. Experimental assessment of injury and potential antidotes.

Severe cutaneous ulceration may occur as a result of contrast media extravasation. We established a definitive animal model for assessing the cutaneous toxicity of commonly employed agents and used this model to evaluate possible antidotes to the effects of contrast media extravasation. The contrast agents studied were: meglumine/sodium diatrizoate 76%, meglumine iothalamate 60% and 43%, meglumine/sodium ioxaglate 60%, iohexol 350, and iopamidol 370, in varying volumes and osmolalities. Hypertonic saline (950 and 1900 mOsm/kg) also was injected. Agents were injected intradermally into BALB/c mice. The higher osmolality agents produced dose-dependent skin ulcerations. The lower osmolality agents failed to produce any skin lesions after the same volume doses. Hypertonic saline produced skin toxicity in a dose-dependent fashion similar to hyperosmolar contrast agents. Three antidotes were tested: hyaluronidase, topical heat, and topical cold. Hyaluronidase significantly reduced skin toxicity when injected immediately following contrast injection. Cold also significantly reduced skin toxicity, while heat caused no improvement.

Animals↗
PubMed1990

Prospective comparison of plain abdominal radiography with conventional and digital renal tomography in assessing renal extracorporeal shock wave lithotripsy patients.

Most publications citing the effectiveness of renal extracorporeal shock wave lithotripsy have used plain abdominal radiography to assess residual calculi after treatment. We compared radiologist sensitivity and specificity in the detection of calculi on plain abdominal radiographs versus conventional film-screen and digital renal tomograms in extracorporeal shock wave lithotripsy patients. Of the patients 50 were imaged before and within 24 hours after lithotripsy. Six radiologists evaluated the resultant 300 studies for the presence and location of calculi. The mean sensitivity for digital tomograms was 83% for pre-lithotripsy and post-lithotripsy studies, which was significantly higher than for plain abdominal radiography and conventional tomography after lithotripsy. However, there were significantly more false positive stone diagnoses associated with digital tomogram interpretation. Signal detection analysis verified the over-all superiority of digital tomography for post-extracorporeal shock wave lithotripsy imaging. Calculus detection by conventional and digital tomography is superior to detection by plain abdominal radiography. However, because we did not perform delayed imaging, it is not possible to say what impact digital tomography might have on the management of extracorporeal shock wave lithotripsy patients.

Humans↗
PubMed1990

Preeminence of lesser splanchnic blood flow in selected patients with generalized portal hypertension.

Although restricted transhepatic portal flow is necessary for development of generalized portal hypertension (GPH), increased splanchnic arterial inflow also contributes to GPH and its clinical sequelae. In this context, we describe 7 male and 6 female patients (mean age 48 years) in whom the lesser splanchnic (gastrosplenic) system played a key role in the signs and symptoms of GPH. These 13 patients (9 with hepatic cirrhosis, 3 with primary myeloproliferative disorder, and 1 with extrahepatic portal block) shared common features of massive splenomegaly, huge splenofundic gastric varices, often with a prominent natural shunt to the left renal vein. Total or near total splenectomy alone or combined where appropriate with coronary vein ligation was effective in controlling varix hemorrhage (10 patients), ascites (3), or complications of an enlarged spleen-anorexia and abdominal pain (3), hemolytic anemia (1) and profound thrombocytopenia with severe epistaxis (1). Intraoperative jejunal portal venography was crucial in operative management in order to establish definitively the presence or absence of coronary venous collaterals, and when present, to verify their operative ligation. These distinctive patients illustrate: 1) GPH is a heterogeneous syndrome of divergent splanchnic circulatory patterns, a feature which should be taken into account in selecting operative treatment; 2) one well-defined subgroup displays prominent hyperdynamic lesser splanchnic and specifically, splenic blood flow as a major contributor to clinical complications; and 3) within this subgroup, splenectomy combined with documented absence or surgical interruption of coronary venous collaterals as corroborated by intraoperative portography is effective alternative treatment.

Adolescent↗
PubMed1989

Non-Hodgkin lymphoma: influence of lymphography, CT, and bone marrow biopsy on staging and management.

This prospective study assesses the contribution of lymphography (LAG), abdominal-pelvic computed tomography (CT), and bone marrow biopsy to the staging and management of 168 consecutive cases of newly diagnosed non-Hodgkin lymphoma (NHL). LAG and/or CT influenced Ann Arbor clinical stage (CS) in 39 patients (23%) and Ann Arbor pathologic stage (PS) in 23 patients (14%) by detection of clinically inapparent retroperitoneal adenopathy and/or extranodal disease. LAG findings raised the CS in eight patients and the PS in six of the eight by showing adenopathy when the CT results were negative. By depicting extranodal disease, CT resulted in the CS being raised in an additional ten patients and the PS in six of the ten. Of the diagnostic tests assessed, bone marrow biopsy and/or cytology had the greatest influence on staging. Clinical staging that included LAG/CT resulted in the identification of only 30 patients with CS IV disease, whereas an additional 53 CS I through CS III patients had their disease stage raised to PS IV due to positive bone marrow biopsy/cytology results. However, 42 of the 53 patients already had advanced (CS III) disease. Initial case management was influenced by LAG, CT, or bone marrow biopsy/cytology results in 27 of 168 patients. LAG/CT results influenced management in 20 of 27 cases, while bone marrow biopsy/cytology results caused initial management changes in only seven of the 27 cases.

Adolescent↗
PubMed1989

Intraoperative arteriography: comparison of conventional screen-film with photostimulable imaging plate radiographs.

This prospective study compared images obtained with a photostimulable imaging plate with matched images obtained with a conventional screen-film combination in 26 patients undergoing intraoperative arteriography. Diagnostic accuracy of the two techniques was assessed objectively, and image quality was assessed subjectively. In 16 patients (62%), the radiation exposure was reduced by 50% for the imaging plate technique by decreasing the mAs level generally used for the screen-film combination. Because of the dynamic range of the imaging plate system, no repeat examinations were necessary, while 12% of the screen-film studies had to be repeated because of over- or under-penetration. Imaging plate studies required 6% more time for processing than screen-film studies. Receiver-operating-characteristic analysis indicated no difference in diagnostic accuracy between the two imaging techniques. Subjective evaluation also revealed no difference in observer preference for imaging plate or screen-film studies. The imaging plate technique is an excellent alternative to screen-film studies in the operating room.

Angiography↗
PubMed1989

Whole-body lymphangioscintigraphy: preferred method for initial assessment of the peripheral lymphatic system.

In 20 patients with congenital and acquired lymphedema in either upper or lower extremities and in four patients without extremity edema, human serum albumin labeled with technetium-99m was injected intradermally into a digital web space of the hand or foot. With a digital gamma camera that permitted a "sweep" of the torso, serial extremity and whole-body lymphagioscintigraphy (LAS) of the peripheral lymphatic system was performed. In 11 patients with acquired lymphedema, a well-defined obstructive pattern was seen, characterized by discrete peripheral lymphatic trunks, delayed or absent depiction of regional nodes, and delayed but extensive soft-tissue tracer extravasation. Five of nine patients with congenital lymphedema showed hypoplasia characterized by poorly defined lymphatic trunks, delayed depiction of regional nodes, and early and extensive extravasation of tracer. The other four patients showed aplasia, with absence of trunks, no depiction of nodes, and little or no tracer extravasation. LAS is technically simple to perform and requires no special training. Radiation exposure is minuscule, and the procedure is safe and without apparent side effects. For these reasons, whole-body LAS should be the preferred method for the initial assessment of congenital or acquired lymphedema.

Adolescent↗
PubMed1989

Detection of pneumothorax: comparison of digital and conventional chest imaging.

To investigate radiologists' performance at interpreting digital radiographic images, we compared the detectability of pneumothoraces on computed radiographic chest images with 0.2-mm pixel size (2.5 Ip/mm) with their detectability on matched conventional screen-film images (5 Ip/mm). Eight radiologists reviewed 50 computed and 50 screen-film chest radiographs from 25 patients with pneumothoraces and 25 patients with other (or no) abnormalities. Four of the readers who best detected pneumothoraces on screen-film examinations performed worse when interpreting computed radiographic studies; the other four readers detected pneumothoraces similarly with both techniques. No relationship was found between the size of a pneumothorax and its likelihood of detection by either technique. These results raise concerns about implementing computed radiography for comprehensive chest imaging.

Adult↗
PubMed1988

Computed radiographic evaluation of simulated pulmonary nodules. Preliminary results.

We evaluated the capabilities of a computed radiography system (CRS) and a standard radiography system (SRS) in the detection of simulated solitary pulmonary lung nodules of various sizes and contrast. A phantom simulated the pulmonary anatomy, and specially shaped plexiglass disks were externally mounted to simulate solitary pulmonary nodules of different diameters and thicknesses. ROC curves were generated based on the performance of each of the radiologists observing each film set. In this preliminary study, the overall performance for both the CRS and the SRS were comparable in detecting simulated pulmonary nodules.

Humans↗
PubMed1988

Chest radiographic abnormalities in Lennert's lymphoma.

In reviewing the medical records of ten patients with Lennert's lymphoma, we found chest radiographic abnormalities in five cases. Two cases had hilar and mediastinal adenopathy without associated parenchymal or pleural disease, and three cases had isolated pulmonary parenchymal abnormalities. In one patient, both the chest radiograph and the histologic findings, obtained by open lung biopsy, mimicked miliary granulomatous disease. This article emphasizes the need to be alert to this aggressive T-cell neoplasm, since its clinical course differs significantly from some of the diseases it tends to imitate. By being aware of the entity and by using thorough pathologic and immunopathologic techniques, difficult cases of Lennert's lymphoma can be successfully diagnosed.

Aged↗
PubMed1988

Combined thrombolytic therapy and percutaneous transluminal angioplasty for treatment of complex arterial graft thrombosis--a case report.

Combined catheter-directed thrombolytic therapy followed by percutaneous transluminal angioplasty (PTA) was successfully performed for the treatment of a thrombosed complex mesenteric artery bypass graft resulting from an anastomotic stenosis. Restenosis of the graft due to neointimal hyperplasia was subsequently treated by PTA, with resultant long-term patency. This approach is an attractive alternative to surgical thrombectomy and graft revision, especially in patients who are poor surgical risks owing to concurrent medical problems.

Aged↗