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Biomedical subjects

M J Shapiro

Publications and source records attributed to M J Shapiro.

At least 19 recordsLinked to original sources
PubMed1992

The effect of shock on blood oxidation-reduction potential.

Oxidation-reduction (redox) potential measurements were made in the blood of rabbits subjected to hemorrhagic shock followed by treatment with a mild oxidizing agent (albumin). Control redox potential reading corrected for pH was -8.8 +/- 1.3 millivolts (mV) in arterial blood (A) and -18.0 +/- 2.0 mV in venous blood (V). This A-V difference indicated that hydrogen equivalents coming from muscle and other tissues were partially consumed in the lungs. A 20-mV drop on the V and a 13 mV on the A side was seen after shock. This did not fully return to control 2 h after return of the shed blood. Infusion of 2 g of albumin/kg/h raised the V redox potential to control, but it returned to untreated levels when the albumin was discontinued. The reductive load imposed on the animal by shock appeared to be large and not readily reversed by reperfusion or by the quantity of albumin given. Thus, it may be concluded that cellular respiration had not been adequately restored. This reductive load may impede recovery by suppression of cellular respiration and other cell and organ functions.

Animals↗
PubMed1992

Branch retinal vein occlusion and quadratic variation in arteriovenous crossings.

To explore further the origin and clinically observed regional variation of branch retinal vein occlusion, we studied fluorescein angiograms of 42 patients (42 eyes) with branch retinal vein occlusion and a control population of 126 consecutive patients. In a statistically significant percentage of crossings, the artery was anterior to the vein in those areas of the retina clinically predisposed to branch retinal vein occlusion. Thirty-nine of the 42 patients with branch retinal vein occlusion sites had artery-anterior-to-vein crossings (P = .002), whereas 183 of all 266 arteriovenous crossings in these same eyes were similarly positioned. The artery lay anterior to the vein in significantly more temporal retinal crossings (337 of 457) than nasal retinal crossings (89 of 149; P = .002). Similarly, significantly more superotemporal quadrant crossings (164 of 209) than inferotemporal quadrant crossings (173 of 248) had the artery anterior to the vein (P = .0045). These results suggested that variation in the pattern of arteriovenous crossings may have a role in the clinical distribution of branch retinal vein occlusion.

Aging↗
PubMed1992

Management of blunt hepatic injuries.

Sixty-three consecutive patients with blunt hepatic trauma were examined. Twenty-four patients underwent immediate operation, and 39 patients were evaluated by computed tomography (CT), of whom 17 underwent operation. Ten patients had no hepatic abnormalities on CT and had operations for associated injuries. Liver injuries were noted in the remaining seven patients, but CT underestimated the injury in four patients. A large hemoperitoneum was present in all seven patients by CT, and the average transfusion was 10 U during initial resuscitation. Twenty-two patients with grade I to III injuries and a small to moderate hemoperitoneum were managed nonoperatively. Six of these patients had transfusions during resuscitation. Only one patient received more than 2 U. There were no deaths and no major complications related to the liver injury. Most patients had repeat CT at 1 week, which demonstrated stable or improving injuries. CT may underestimate the degree of liver injury. Nonoperative management is appropriate in stable patients with grade I to III injuries and a small to moderate hemoperitoneum. These patients should require no more than 2 U of blood, and repeat scans should demonstrate a stable injury.

Accidents, Traffic↗
PubMed1992

Intraarterial chemotherapy with limb-sparing resection of large soft-tissue sarcomas of the extremities.

Fifteen patients with large (average, 15-cm), high-grade soft-tissue sarcomas of the extremities received prolonged selective intraarterial infusions of chemotherapeutic agents in an attempt to permit limb-sparing resection of these tumors, which would otherwise have required amputation. There were seven malignant fibrous histiocytomas, four liposarcomas, two fibrosarcomas, one leiomyosarcoma, and one rhabdomyosarcoma; 73% were grade III. Seven patients underwent two catheterizations, for a total of 22 infusions, which averaged 11.3 days each. There were four catheterization-related complications, including catheter occlusion or dislodgement in one patient each and two cases of arterial thromboembolism in patients in whom anticoagulant dose was not adequate. Both of the latter patients required thrombectomy; one developed gangrene, which precluded limb-sparing surgery. Thirteen of the 15 patients underwent limb-sparing resections, and two underwent amputations. No wound complications occurred. With a median follow-up of 36 months (mean, 34 months), life-table analysis indicates overall and disease-free survivals of 72% and 59%, respectively, at 2 years and 64% and 59% at 3 years. In comparison to other reported therapies, this technique permits limb salvage in most patients without the high wound complication rate associated with preoperative radiation therapy, with equivalent local disease control and survival.

Adult↗
PubMed1992

Pyrimidine-enhanced purine uptake in hepatocytes and improved survival from hypovolemic shock.

To assess the effect of pyrimidines on the incorporation of purines into rat hepatocytes, monolayer preparations of hepatocytes were incubated with radiolabeled precursors and their uptake determined. The uptake of purine precursors (inosine monophosphate, inosine, and hypoxanthine) was 27.8 +/- 1.31 nmoles per well, per 30 min. In the presence of added pyrimidines (uridine monophosphate, uridine, and orotate), this increased by 22%. Further enhancement (45%) was observed when L-dihydroxyphenylalanine (L-DOPA) plus pyridoxal-5'-phosphate was added to the purine/pyrimidine incubation medium. The effect of increased uptake of purines on survival after hypovolemic shock was also studied. Rats were bled to a blood pressure of 40 mmHg for 105 min and then treated with return of shed blood plus saline with or without purines and pyrimidines. Survival at 24 hr was 43% (15/35) in control animals, 66% (8/12) (P = 0.276) when treated with inosine monophosphate (IMP) and aspartate (60 mumoles/kg each), and 83% (10/12) (P = 0.037) for IMP with aspartate and orotate treatment (60 mumoles/kg each). Thus, the addition of orotate enhanced survival possibly by promoting salvage or by uptake of purines. Nucleotide concentrations in the livers of animals after shock which had received IMP and orotate demonstrated a return of both ATP and energy charge to normal, further indicating the value of this treatment.

Adenosine Diphosphate↗
PubMed1992

Continuous oscillation therapy for the treatment of pulmonary contusion.

Pulmonary contusion as a result of blunt trauma carries significant morbidity and mortality. In an attempt to improve therapy, a prospective study was performed in which 30 patients were randomized to either receive or not receive continuous oscillation therapy on the Kinetic Treatment Table. Pulmonary contusion was defined by mechanism of injury (blunt trauma secondary to a motor vehicle accident), hypoxemia, and radiographic confirmation. Patients who received continuous oscillation therapy had a significantly higher injury severity score (more severely injured group of patients), yet had a hospital course similar to those patients who did not receive continuous oscillation therapy and had a significantly lower injury severity score.

Adult↗
PubMed1992

Clearance and maintenance of blood nucleotide levels with adenosine triphosphate-magnesium chloride injection.

ATP-MgCl2 has been found to be helpful in experimental animals after shock and ischemia with improvement in organ function and survival. The reasons for this pharmacologic action are unclear. To evaluate the clearance and circulation of ATP and its metabolites after intravenous injection, 20 rabbits received ATP-MgCl2 as a bolus injection or a continuous intravenous infusion. Arterial blood was withdrawn, and ATP and its metabolites were measured using a high-performance liquid chromatography (HPLC) technique with ultraviolet (UV) absorption. Forty seconds following a bolus injection, only 1% of the injected dose was present in arterial blood as ATP, and at 280 sec only inosine remained. With a 60 min continuous ATP-MgCl2 infusion, the inosine level peaked at 62.9% at 30 min and was 37.6% at 60 min, whereas ATP was 4.9% and AMP was 17.4% at 60 min. Thus a single dose of ATP-MgCl2 has a half-life of less than 40 sec as ATP. With a continuous infusion, although some ATP circulates, inosine and AMP are the major remaining nucleotides. Thus, the beneficial effects of ATP-MgCl2 may be through ATP itself with magnesium or with adenine nucleotide metabolites for recycling of the nucleotides, phosphorylation of cell membrane inositides, and/or its vasoactive effects.

Adenosine Diphosphate↗
PubMed1992

Argon beam coagulator hepatorrhaphy in potential donors.

Advances in medical technology have provided clinicians with the means to successfully treat life-threatening illnesses and injuries. For trauma surgeons, the acuteness and severity of thoracic and abdominal injuries may not allow time for complete, continuous neurologic examination, including computed tomography. The situation may arise in which urgent, major surgical intervention is necessary in a neurologically moribund patient. One such patient is presented herein; the Argon Beam Coagulator is used to repair a severe liver injury in this unstable trauma victim on whom a complete neurologic examination could not be performed. Cerebral death ensued and the repaired liver was successfully transplanted.

Accidents, Traffic↗
PubMed1991

Management of the dislocated crystalline lens with a perfluorocarbon liquid.

Vitreoretinal surgery allows the effective removal of soft to moderately dense crystalline lens fragments, using the vitrectomy probe and the ultrasonic fragmentation probe. Hard lenses cannot be removed with these instruments. Previously described techniques for removal of hard lenses include trapping the lens anteriorly with needles, cryoextraction of the lens in an air-filled eye, and manipulation with sodium hyaluronate. These methods are difficult and dangerous in some cases. We used perfluorocarbon liquid to facilitate the safe removal of a surgically luxated hard crystalline lens. Injection of the perfluorocarbon liquid floated the lens off the retinal surface and into the anterior vitreous cavity. In this location, the lens was delivered by using standard extracapsular cataract extraction techniques. This technique allowed removal of the hard crystalline lens with minimal manipulation, and was helpful in the setting of poor media clarity.

Aged↗
PubMed1991

Stress gastritis revisited.

In current ICU populations, overt bleeding from stress gastritis occurs in 10% to 20% of patients. Bleeding rates may be reduced to about 3% in patients receiving prophylactic therapy. Although patients with bleeding have higher mortality rates than other critically ill patients, it is not clear that the mortality rate is improved with prophylactic therapy, as most patients die from their underlying disease. As new complications of prophylactic therapy are identified, better definitions of the population at risk to develop complications of stress gastritis will be necessary to select those patients who will benefit most from prophylactic therapy.

Antacids↗
PubMed1991

Recanalization of an occluded aortoiliac bypass graft with Palmaz stents.

Four tandem Palmaz balloon-expandable vascular stents were used to recanalize the completely occluded limb of an aortoiliac bypass graft after failure of thrombolysis and conventional angioplasty. The resting peak-systolic pressure gradient across the occluded limb was reduced from 68 to 13 mm Hg. The patient's rest pain resolved, and the ankle-brachial index rose from 0.54 to 0.78. No embolization or stent-related complications occurred. The graft remains patent as determined with noninvasive studies obtained 8 months later.

Anastomosis, Surgical↗
PubMed1991

Transhepatic laser lithotripsy of choledocholithiasis: initial clinical experience.

Three patients with symptomatic intra- and extrahepatic choledocholithiasis who were not good candidates for retrograde endoscopy, surgery, or extracorporeal shock wave lithotripsy (ESWL) were treated successfully with endoscopically guided tunable dye laser lithotripsy via a 12-F transhepatic sheath. There were no complications secondary to the use of the laser. On the basis of this initial experience, transhepatic laser lithotripsy is a technically feasible and safe alternative when choledocholithiasis cannot be managed with retrograde endoscopy, ESWL, or surgery. Its role in the management of choledocholithiasis relative to other transhepatic techniques remains to be determined.

Adult↗
PubMed1991

Magnetic resonance chemical shift imaging and spectroscopy of atherosclerotic plaque.

An in vivo magnetic resonance imaging (MRI) technique for identification and characterization of atherosclerotic plaque was assessed in animal and human models. Atherosclerosis was induced in the abdominal aorta of four rabbits by a combination of balloon denudation and a high cholesterol diet. In vivo conventional spin-echo and fat/water suppressed images of the rabbit aortae were obtained at 1.5 T. Chemical shift imaging (CSI) was achieved using a hybridization of selective excitation and modified Dixon techniques. These techniques were then used to obtain images of atherosclerotic lesions in the carotid arteries of four patients prior to endarterectomy. The MRI results were corroborated by histologic and high-resolution proton MR spectroscopic (8.5 T) analysis of rabbit aorta, human carotid endarterectomy, and six additional human superficial femoral and iliac atherectomy specimens. All animal and human lesions were classified as either fatty streaks or fibrotic plaque. When compared to conventional spin-echo images, fat suppression by CSI substantially improved the measured contrast-to-noise ratio between plaque and vessel lumen, and enhanced its discrimination from periadventitial fat. In contrast, water suppression eliminated visualization of plaque due to the negligible amount of isotropic (liquid-like) signal from the immobilized lesion lipids. Magnetic resonance spectroscopy corroborated the CSI results by demonstrating broad, ill-defined fat resonances characteristic of nonmobile lipids in both human and rabbit atherosclerotic lesions. These findings indicate that in vivo MRI of plaque is technically feasible and can be markedly improved using chemical shift imaging.

Animals↗
PubMed1991

Cardiovascular evaluation in blunt thoracic trauma using transesophageal echocardiography (TEE)

Blunt chest trauma can result in significant cardiothoracic injury, which can include cardiac contusion, aortic injury, and myocardial valvular injury. Nineteen patients with no prior history of cardiac abnormalities who sustained severe blunt chest trauma and had widening of the mediastinum on chest radiographs were prospectively evaluated using transesophageal echocardiography (TEE). In each instance TEE was performed without difficulty, excellent images were obtained of the aorta and heart, and no complications were noted. Abnormalities were seen in 12 (63%) patients, with hypokinetic regional wall motion consistent with cardiac contusion demonstrated in five (26%) patients. Tricuspid regurgitation was found in three (16%) patients, and aortic and mitral regurgitation in one (5%) patient each. Aortic wall hematomas were seen in two patients, one of whom had an intimal tear on aortography, and a pericardial effusion was seen in one patient with an aortic intimal tear confirmed angiographically. Thus TEE can be performed safely in the acute setting of patients sustaining severe blunt chest trauma and yield useful information with respect to cardiovascular function and the aorta.

Adult↗
PubMed1991

Cardiac injury complicating traumatic asphyxia.

During a 3-year period (1986-1989), 8 patients were seen at St. Louis University Medical Center exhibiting the stigmata of traumatic asphyxia. Fewer than 200 cases of traumatic asphyxia have been reported and there is only a single report of a cardiac injury. In this series, 3 of 8 (37.5%) patients were found to have an injury to the heart: two cardiac contusions and a ventricular rupture. Five patients were crushed in motor vehicle collisions, one by an elevator counterweight, and two patients by river barges. Injuries associated with these patients include pulmonary contusion, hemopneumothorax, traumatic pneumatocele, traumatic retinopathy, bone fractures, mental confusion, and liver contusion. There was one death in the series, a patient with rupture of the right ventricle and severe splenic and liver injuries. The cardiac status of the patients was evaluated by serial serum cardiac enzyme determinations, electrocardiograms, and echocardiography. This report illustrates the importance of complete cardiac evaluation in patients with traumatic asphyxia.

Accidents, Occupational↗