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Biomedical subjects

N D Kon

Publications and source records attributed to N D Kon.

At least 55 records · Page 3Linked to original sources
PubMed1990

Hypoplastic left heart syndrome: palliation without cardiopulmonary bypass.

Our 100% mortality rate with first-stage palliation of hypoplastic left heart syndrome performed with cardiopulmonary bypass led us to a procedure not necessitating bypass. In nine neonates with this congenital heart defect, a woven Dacron graft was placed from the main pulmonary artery to the descending thoracic aorta. The patent ductus arteriosus was ligated and the main pulmonary artery banded distal to the graft and proximal to the bifurcation. Five patients were extubated within 4 days. Only low-dose inotropic support was required in eight of the nine. There were no bleeding problems. Four patients died in the hospital: one of Candida sepsis at 81 days, one of low cardiac output at 2 days, and two of restrictive atrial septal defect at 3 and 5 days. The five living patients were discharged 11 to 80 days postoperatively (mean 38 days). We now perform balloon septostomies preoperatively in all patients and believe that this will improve the survival rate. We believe this simpler approach to the treatment of hypoplastic left heart syndrome may allow survival for a cardiac transplant or a staged Fontan procedure at a later date for more definitive treatment.

Cardiac Catheterization↗
PubMed1989

Radial artery-to-aorta pressure difference after discontinuation of cardiopulmonary bypass.

To test whether the radial artery-to-aorta pressure gradient seen in some patients after cardiopulmonary bypass (CPB) is due to reduction in hand vascular resistance, the authors compared pressures in the ascending aorta with pressures in the radial artery before and after CPB in 12 patients. They increased hand vascular resistance by briefly occluding the radial and ulnar arteries at the wrist and recorded that effect on the radial artery-to-aorta pressure relationship. They also recorded the effect of wrist compression on radial artery pressures before and after CPB in 38 patients not having aortic pressure measurements. Before CPB in the first 12 patients, the radial systolic arterial pressure (SAP) was significantly higher (P less than 0.05) than the ascending aortic SAP, and wrist compression did not significantly affect that difference (P greater than 0.05). After CPB, the radial artery and aortic SAPs were not statistically different (P greater than 0.05), but wrist compression restored the higher radial artery SAP. The mean arterial pressure (MAP) was equal in four patients and 1-3 mmHg higher or lower in eight patients before CPB, and wrist compression did not alter those relationships. After CPB, MAP was equal in four patients; radial MAP was 1-3 mmHg higher or lower in six patients, and 7 and 10 mmHg lower in the last two patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1988

Management of injuries from liquid lye ingestion.

The simultaneous admission of nine youths to our institution following their ingestion of concentrated sodium hydroxide (which had been mistaken for wine) provided us with a unique opportunity to manage corrosive esophageal injuries ranging in severity from second-degree oral mucosal injury alone to full-thickness hypopharyngeal, esophageal, and gastric injury. The severity of injury was graded first on the basis of symptoms and physical examination of the mouth, and then in the operating room by rigid esophagoscopy. This procedure provided a logical approach to management. Three patients with second-degree oral burns required no surgery. Six patients required laparotomy with gastrostomy and/or chimney feeding jejunostomy, one required immediate esophagogastrectomy, and three required immediate total or subtotal gastrectomy. There were no deaths. Three patients have subsequently required esophageal replacement and three others have required repeated dilatations. At 2-year followup, all nine maintain their nutritional status orally, and all except for the previously mute patient can phonate. Ingestion of liquid lye requires a much more aggressive diagnostic and therapeutic approach than is currently recommended for ingestion of caustics in general. On the basis of our experience with these nine patients, we suggest the following for esophageal liquid lye injury: 1) early evaluation of the esophagus by esophagoscopy; 2) with esophageal burns, urgent laparotomy to assess gastric damage and gastrostomy to pass a string for subsequent retrograde dilatations; 3) adequate resection of stomach for gastric burns; 4) with deep esophageal burns, early esophagectomy.

Adolescent↗
PubMed1986

Ticlopidine versus aspirin and dipyridamole: influence on platelet deposition and three-month patency of polytetrafluoroethylene grafts.

In an attempt to establish a specific drug regimen that would retard neointimal fibrous thickening (NFT) and promote patency of small arterial grafts, we studied acute platelet accumulation and 3-month patency of 4 mm polytetrafluoroethylene (PTFE) grafts in dogs treated with oral aspirin (2 mg/kg/day) in combination with dipyridamole (5 mg/kg/day) (ASA/D) or ticlopidine (25 mg/kg/day) (T). After 3 days of treatment, 15 dogs were given indium 111-labeled autologous platelets and then had bilateral femoral artery grafts placed (control, 10 grafts; each drug group, 10 grafts). The calculated graft radioactivity expressed as average counts per 10 minutes +/- standard error of the mean (SEM) was as follows: control = 542,003 +/- 63,991; ASA/D = 135,163 +/- 14,443 (p less than 0.001, Student's t test); T = 104,650 +/- 14,004 (p less than 0.001). Bilateral femoral artery and carotid artery grafts were placed in 15 other dogs (control, 20 grafts; each drug group, 20 grafts). Three months later the 60 grafts were excised and their patency recorded: control = 20% (4 of 20 grafts); ASA/D = 70% (12 of 17 grafts) (p less than 0.01, chi-square analysis); T = 30% (6 of 20 grafts) (p greater than 0.05). Mean anastomotic NFT +/- SEM of each graft was measured with an ocular micrometer: control = 1.6 +/- 0.2 mm; ASA/D = 0.7 +/- 0.2 mm (p less than 0.001, Student's t test); T = 1.3 +/- 0.2 mm (p greater than 0.1).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1986

Pseudocalculus sign. A pitfall of static cholangiography.

The pseudocalculus formation was first noted by Caroli in 1960, and was first called a sign by Beneventano and Schein in 1968. It is a cholangiographic illusion that appears as a filling defect in the distal common bile duct when static or "spot" films are exposed during the contractile phase of choledochal sphincter activity. Although first noted and most frequently seen in T-tube cholangiography, it is seen also during intravenous and intraoperative cholangiography. Because it mimics radiographically an impacted stone in the distal common bile duct, its delineation is critical to avoid unnecessary instrumentation of the common bile duct or even reoperation. In this review the authors discuss briefly the anatomy and physiology of the distal common bile duct and the etiology, differential diagnosis, and recognition of the pseudocalculus sign.

Ampulla of Vater↗
PubMed1985

Myocardial biopsy drill: construction details and techniques.

The modification of currently available dental equipment to construct a myocardial biopsy drill by the technique of Poole et al. (P. E. Poole, G. F. Norris, R. M. Lewis, and J. W. Covell, J. Appl. Physiol. 24: 832, 1968) is described. In dogs, five to seven full-thickness myocardial cores 3 mm in diameter and weighing 40 to 70 mg could be obtained consistently with the drill without affecting left ventricular function. The positive pressure/negative pressure system allowed separation of contaminating blood from the myocardial sample and rapid myocardial freezing. Assessment by a modification of the technique of Estabrook et al. (R. W. Estabrook, J. R. Williamson, R. Frenkel, and P. K. Maitra, In R. W. Estabrook and M. E. Pullman (Eds.), Methods in Enzymology, New York: Academic Press, 1967. Vol. 10, p. 474). yielded myocardial ATP levels of 32.12 +/- 0.90 nmole/mg of protein.

Adenosine Triphosphate↗
PubMed1985

Greater curvature gastroplasty. Follow-up at 34 months.

This retrospective study analyzes the results of 198 consecutive greater curvature gastroplasties performed in 23 male and 175 female patients with morbid obesity. The gastroplasty consisted of the creation of a 30-50 cm3 proximal gastric pouch by a double application of the TA-90 stapler, modified by removing three staples near the pin and trimming the cartridge to prevent crushing of the stomach at the outlet. The outlet was calibrated to a diameter of 1 cm and reinforced with a polypropylene seromuscular suture. No deaths occurred; postoperative complications included 32 superficial wound infections (16.2%), 24 incisional hernias (12.0%), 15 staple-line disruptions (7.6%), seven gastric outlet obstructions (3.5%), five subphrenic abscesses (2.5%), three perforations (1.5%), one splenic infarction, and one enterocutaneous fistula. One hundred sixty-one (81%) patients have been followed for a mean of 34 months (range 24 to 56 months); their mean weight loss is 36.4 per cent +/- 32.9 per cent of excess body weight. Only 45.5 per cent of these patients can be considered to have had satisfactory weight loss. Because this is not as effective as other forms of surgical therapy, the authors do not recommend greater curvature gastroplasty for the treatment of morbid obesity.

Adolescent↗
PubMed1984

Comparison of suture technique on patency of polytetrafluoroethylene-microarterial anastomoses.

Polytetrafluoroethylene (PTFE) grafts, 1 mm in internal diameter, were interpositioned in the infrarenal aortas of 20 adult Sprague-Dawley rats with either continuous or interrupted sutures. The interrupted-suture (I-S) technique was used in ten rats, the continuous-suture (C-S) technique in the other ten. After followup of 90 days, the overall patency rate for the 20 rats was 95% (19/20); all grafts in the C-S group were patent; one graft in the I-S group had occluded on the day of operation. Since excellent patency rates were obtainable with these minute PTFE grafts placed in the rat aorta by either technique, the speed with which the C-S technique can be accomplished appears to make it preferable.

Animals↗
PubMed1984

Abdominal wound closure. A comparison of polydioxanone, polypropylene, and Teflon-coated braided Dacron sutures.

A midline abdominal wound was made in 135 Harlan Sprague-Dawley rats, and the fascia was then closed by the continuous suture technique with 4-0 absorbable monofilament polydioxanone sutures (n = 45 rats), 4-0 permanent monofilament polypropylene sutures (n = 45 rats), or 4-0 Teflon-coated braided Dacron sutures (n = 45 rats). At 1-, 2-, and 6-month intervals, wound-bursting pressures were determined in 15 animals from each group. At 1 month and at 6 months, there was no significant difference in wound-bursting strength among the three types of sutures. At 2 months, wounds closed with Teflon-coated braided Dacron were significantly stronger than wounds closed with the other types of sutures. In most of the braided Dacron suture animals, the fascia burst in areas other than the abdominal wound, indicating that the wound was stronger at that time than was the surrounding fascia. There is no advantage to that added strength, and braided Dacron sutures have been shown to cause greater tissue reaction than monofilament sutures. Therefore, except in patients with poor wound healing who are highly susceptible to dehiscence and in whom permanent low-tissue-reaction sutures may be beneficial, the authors recommend a running suture technique using absorbable monofilament suture, such as polydioxanone, for the routine closure of clean abdominal wounds.

Abdomen↗
PubMed1984

Suture technique and wound-bursting strength.

Despite advances in wound healing, fascial dehiscence continues to be a problem in celiotomy wounds. Experimental and clinical studies on suture material and on patient-related factors in wound disruption are abundant, but little attention has been given to mechanical factors in wound closure, although they may be of greater importance. A midline abdominal wound was made in 120 Harlan Sprague-Dawley rats, and the fascia was closed with Dacron in one of six ways: simple interrupted, interrupted figure-of-eight, and running, each tied loosely in one half of each group and tightly in the other half. One week later, the rats were reanesthetized and wound-bursting strength was measured. In general, the running suture technique resulted in the greatest wound-bursting pressures. A loosely tied figure-of-eight technique was nearly as good as a loosely tied running stitch, but tying figure-of-eight sutures tightly caused a significant decrease in wound-bursting pressure. The simple interrupted technique was unaffected by suture tension but was generally inferior to the running stitch in terms of wound-bursting strength. Histologic studies were performed, but most of the disparity in wound strength among the suture techniques apparently was due solely to mechanical factors. Closing midline abdominal fascial wounds with a running suture may be a superior method of closure in clean, incised wounds.

Abdomen↗
PubMed1984

Inhibition of platelet deposition on polytetrafluoroethylene grafts by antiplatelet agents.

The effects of ibuprofen (Motrin), dipyridamole (Persantine), and prostacyclin on the deposition of platelets on polytetrafluoroethylene grafts (5.5 cm long, 4 mm internal diameter implanted into both femoral arteries of 21 dogs) were studied by harvesting autologous platelets, labeling them with 51Cr, and reinjecting them 15 minutes before cross-clamping. Arterial flow was adjusted to 65 ml/min and monitored continuously. Ibuprofen (12.5 mg/kg) and dipyridamole (2.5 mg/kg) were each administered as a single intravenous injection in four dogs (eight grafts) and five dogs (10 grafts), respectively. Prostacyclin (50 ng/kg/min) was administered by continuous intravenous infusion in five dogs (10 grafts). Seven dogs (14 grafts) served as controls. Grafts were removed 2 hours after implantation, and radioactivity (counts per 10 minutes) was determined in four segments of each graft (including both anastomoses) with a gamma-counter. Counts were averaged for each group of dogs. Significance was calculated by the Student t test. Platelet deposition in control dogs averaged 10,033.9 +/- 1134.2 SE; that in prostacyclin-treated dogs averaged 2513.7 +/- 276 SE (p less than 0.001); that in ibuprofen-treated dogs averaged 5453.4 +/- 1336.3 SE (p = 0.02); that in dipyridamole-treated dogs averaged 11,213.7 +/- 1632.5 SE (p = 0.55). These data demonstrate the effectiveness of prostacyclin and ibuprofen in reducing platelet deposition on polytetrafluorethylene grafts in dogs.

Animals↗
PubMed1984

Postmastectomy angiosarcoma.

Six cases of postmastectomy angiosarcoma of the upper extremity have been treated at the North Carolina Baptist Hospital/Wake Forest University Medical Center over the past 25 years. Five patients had typical ductal carcinoma; one patient had mammary Paget's disease. Two patients, including the patient with Paget's disease, had bilateral mastectomies. The five patients with ductal carcinoma had received postoperative radiation therapy. The mean interval between mastectomy and the appearance of angiosarcoma was 17.5 years. Significant lymphedema of the upper extremity preceded the appearance of angiosarcoma in all six patients, and it appears important that special care be taken during mastectomy to preserve the integrity of the lymphatic system. The patient treated with interscapulothoracic amputation is alive at 2 years postamputation; the five patients whose angiosarcomas were treated with wide excision or radiotherapy died an average of 4.5 years later. Interscapulothoracic amputation is recommended as the initial treatment of postmastectomy angiosarcoma of the upper extremity.

Adult↗
PubMed1983

Measurement of extravascular lung water in sheep during colloid and crystalloid resuscitation from smoke inhalation.

The pathophysiology of pulmonary inhalation injury, a major cause of morbidity and mortality from fires, is poorly understood. To examine the effects of colloid and crystalloid resuscitation on extravascular lung water (EVLW) during a standard smoke inhalation injury, we subjected 12 sheep to 8 minutes of cool pine smoke inhalation. The animals were then resuscitated to a pulmonary capillary wedge pressure (PCWP) of 10 +/- 1.5 mm Hg with either lactated Ringer's solution or plasma protein derivative. EVLW, cardiac output, vascular resistance, colloid oncotic pressure (COP), arterial and pulmonary artery pressures, PCWP, and blood gases were monitored during 4 hours of resuscitation. In colloid-treated animals, EVLW increased from 8.3 +/- 1.2 to 11.1 +/- 0.9 ml/kg with injury; it increased only to 12.5 +/- 1.3 ml/kg during resuscitation. In crystalloid-treated animals, EVLW increased from 8.0 +/- 1.0 to 10.3 +/- 0.8 ml/kg with injury and further increased to 17.4 +/- 1.6 ml/kg during resuscitation, a level significantly higher than that in the colloid group (P less than 0.05). The increases in EVLW were associated with progressive hypoxia, which was worse in the crystalloid group. In the crystalloid group, COP decreased from 27.3 +/- 0.9 to 14.2 +/- 0.4 mm Hg and intravascular driving force (COP-PCWP) dropped from 17.6 to 3.26 +/- 1.5 mm Hg; COP and COP-PCWP were maintained in the colloid group. These data demonstrate that supporting serum COP minimizes the increase in EVLW with smoke inhalation injury and suggests that smoke inhalation does not lead to a dramatic increase in alveolar capillary membrane permeability to protein.

Animals↗
PubMed1976

Ability of delayed-type hypersensitivity reactions to distinguish tumor-associated antigens and histocompatibility antigens in soluble extracts from murine fibrosarcomas.

The footpad swelling (FPS) test for delayed-type hypersensitivity in the mouse was evaluated for its ability to measure both tumor-associated antigens (TAA) and histocompatibility (H) antigens solubilized from methylcholanthrene (MCA) induced fibrosarcomas of C57B1/6 (B6) mice. Tests for TAA were performed in mice immune to syngeneic tumors while H-antigens were assayed in mice immunized with skin allografts. FPS was most intense in B6 mice challenged with TAA from the immunizing B6 tumor, but also occurred in response to cross-reactive TAA solubilized from another B6 fibrosarcoma. Tests for tumor-associated H-antigens in allograft immune mice were strongly positive in response to donor/recipient H-antigen differences and proved sensitive to shared third-party H-antigen differences. Comparison of soluble antigens from the same tumor maintained in vitro and in vivo revealed that, while both TAA and H-antigens could be detected in preparations from the in vivo tumor line, only TAA and not H-antigens could be detected by RPS in extracts prepared from the in vitro tumor line. These experiments have demonstrated that the mouse FPS test can distinguish both TAA and H-antigen specificities persent in the same complex mixture of tumor-cell antigens.

Animals↗
PubMed1976

Measurement of H-2 and non-H-2 antigens in the mouse with the footpad swelling test.

The footpad swelling (FPS) test for delayed-type hypersensitivity in the mouse was evaluated for its ability to measure histocompatibility (H) antigens present on intact spleen cells or solubilized from a methylcholanthrene-(MCA) induced fibrosarcoma. Mice were immunized to H-antigens (H-2 or non-H-2) with skin allografts and challenged 14 days later with test antigens. Spleen cell-bound and solubilized H-antigens elicited strong and specific FPS reactions in allograft-immunized but not in unimmunized mice. The test could distinguish H-2 from non-H-2 antigens as well as D from KI region specificities of the H-2 gene complex. These experiments suggest that the FPS test is a reliable in vivo method for measuring both cell-bound and solubilized H-antigens in the mouse.

Animals↗
PubMedDate not supplied

The perils of esophageal prosthesis placement in malignant tracheoesophageal fistula.

Endoesophageal prostheses are sometimes used in palliative therapy of esophageal carcinoma. Placement or subsequent manipulation of these devices may require general anesthesia, and these anesthetics are fraught with potential complications, both from the patient's illness and from the prosthesis itself. The two patients in our report presented anesthetic challenges, including acute upper airway obstruction occurring outside the operating theater and management of malignant tracheoesophageal fistula.

Aged↗