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Biomedical subjects

D L Diamond

Publications and source records attributed to D L Diamond.

At least 19 recordsLinked to original sources
PubMed1997

Concomitant orthopedic and vascular injuries as predictors for limb loss in blunt lower extremity trauma.

Lower extremity trauma with concomitant orthopedic and vascular injury is associated with a high degree of limb loss. Despite successful arterial repair, many patients will ultimately require amputations. The effect of associated orthopedic injuries on limb loss in patients with lower extremity arterial injuries is investigated. From 1989 to 1994, 52 infrainguinal arterial injuries were identified among 365 vascular trauma patients. Clinical determinants were retrospectively assessed for the ability to predict postoperative amputations. Femoral artery injuries were present in 23 patients, with 53 per cent the result of blunt trauma. The incidence of lower extremity fractures was 53 per cent (60% open). Seventy-nine per cent of femoral artery injuries were repaired with saphenous vein grafts. Popliteal artery injuries were present in 13 patients, with 77 per cent the result of blunt trauma. The incidence of lower extremity fractures and posterior knee dislocations was 85 per cent (73% open) and 38 per cent, respectively. Ninety-two per cent of injuries were repaired with saphenous vein grafts. Tibial artery injuries were present in 16 patients, with 44 per cent the result of blunt trauma. The incidence of lower extremity fractures was 81 per cent (46% open). Twenty-five per cent of tibial artery injuries were treated with arterial repair, and 31 per cent with arterial ligation. Fourteen above-knee (AKA) and two below-knee amputations were performed. Amputation rates were 26.1 per cent (three AKAs) for femoral, 53.8 per cent (seven AKAs) for popliteal, and 38 per cent (four AKAs, two below-knee amputations) for tibial artery injuries. At the popliteal and femoral locations, greater than two long-bone fractures was predictive of amputation. For tibial arteries, one-vessel (n = 10), two-vessel (n = 3), and three-vessel (n = 3) injuries were associated with 20, 33, and 100 per cent amputations rates, respectively. Blunt injury, pulseless extremity, need for arterial repair (rather than ligation or no therapy), increasing number of injured tibial vessels, and multiple long-bone fractures were predictors of amputation (P < 0.05). Distal vascular injuries combined with complex orthopedic fractures are more likely to result in limb loss. Two or more long-bone fractures is predictive of amputation at all three locations.

Amputation, Surgical↗
PubMed1997

Predictors of survival after inferior vena cava injuries.

In patients with inferior vena cava (IVC) injuries, predictors of survival are investigated. From 1987 to 1995, 27 IVC injuries were identified among 514 patients with vascular trauma. The ability of clinical determinants to predict survival were retrospectively assessed. IVC injuries occurred in 7 females and 20 males (mean age, 27.7 +/- 2.5 years) from both blunt (n = 14) and penetrating (n = 13) trauma. The mean revised trauma score was 10.2 +/- 0.6. Injuries were treated by primary repair (n = 22), ligation (n = 4), or prosthetic grafting (n = 1). Thirteen patients died (48%), 10 within 12 hours of admission. Suprahepatic (n = 2), retrohepatic (n = 12), suprarenal (n = 1), and infrarenal (n = 12) injuries were associated with 100, 67, 100, and 20 per cent mortality, respectively. Blood transfusions (16 +/- 4 vs 23 +/- 4 units), coagulation factor replacement (7 +/- 2 vs 7 +/- 2 units), and electrolyte solution use (8.6 +/- 1.4 vs 9.6 +/- 1.4 L) were similar among survivors and nonsurvivors. Four complications [venous hypertension (n = 2), IVC thrombosis (n = 1), and pulmonary embolus (n = 1)] occurred in the 14 survivors (28.6%). Blunt injury, revised trauma score, free perforation, injury location, intraoperative hypotension, and blood loss were predictive of mortality. IVC injuries remain extremely lethal, and improved survival is associated with infrarenal penetrating injuries and a contained hematoma.

Adult↗
PubMed1996

Regulation of GLUT1-mediated sugar transport by an antiport/uniport switch mechanism.

Avian erythrocyte sugar transport is stimulated during anoxia and during exposure to inhibitors of oxidative phosphorylation. This stimulation results from catalytic desuppression of the cell surface glucose transporter GLUT1 [Diamond, D., & Carruthers, A. (1993) J. Biol. Chem. 268, 6437-6444]. The present study was undertaken to investigate the mechanisms of GLUT1 suppression/desuppression. Sugar uniport (sugar uptake or exit in the absence of sugar at the opposite side of the membrane) is absent in normoxic avian erythrocytes, but sugar antiport (sugar uptake coupled to sugar exit) is present. Exposure to cyanide and/or to FCCP (mitochondrial inhibitors) stimulates erythrocyte sugar uniport but not sugar antiport. K(m)(app) for 3-O-methylglucose uniport and antiport are unaffected by metabolic poisoning. Ki(app) for inhibitions of 3-O-methylglucose uniport by cytochalasin B and forskolin (sugar export site ligands) are unaffected by progressive stimulation of sugar uniport. Cyanide and FCCP stimulation of 3-O-methylglucose uniport are associated with increased AMP-activated protein kinase activity. Purified human GLUT1 is not phosphorylated by exposure to cytosol extracted from poisoned avian erythrocytes. FCCP does not stimulate GLUT1-mediated 3-O-methylglucose uptake in K562 cells but does increase K562 AMP-activated protein kinase activity. FCCP stimulation of 3-O-methylglucose uniport in resealed erythrocyte ghosts requires cytosolic ATP and/or glutathione. The nonmetabolizable ATP analog AMP-PNP cannot be substituted for ATP in this action. These results are contrasted with allosteric regulation of human erythrocyte sugar transport and suggest that avian erythrocyte sugar transport suppression results from inhibition of carrier uniport function. Uniport suppression is not mediated by interaction with cytosolic molecular species that bind to the sugar export site. The antiport to uniport switch mechanism requires ATP hydrolysis, is associated with elevated AMP-activated kinase function, and, if triggered by this kinase, is mediated by factors absent in K562 cells and downstream from the kinase.

3-O-Methylglucose↗
PubMed1996

Blunt carotid injury: reassessing the role of anticoagulation.

Twenty patients with blunt mechanism injuries to the internal carotid artery were treated over a 10-year period. The purpose of this review is to assess the necessity and timing of anticoagulation as a primary therapeutic modality in patients with this injury. Sixteen patients (80%) survived, the majority with normal neurologic function. Twelve patients with either unilateral or bilateral carotid mural injury were anticoagulated. Ten survived with normal neurologic function. Five patients in the heparin anticoagulant group had a significant delay in the initiation of anticoagulation. All recovered without deficits. Two patients were treated with aspirin alone and recovered without deficits. Two patients received no treatment; one survived without deficits, and the nonsurvivor succumbed to a severe head injury. Therefore, a total of nine patients were either not treated with heparin or had a significant delay in the initiation of heparin. Eight of nine (88%) in this group recovered without deficit. A delay in the initiation of heparin therapy, no therapy, or the institution of antiplatelet therapy may all be appropriate in the initial management of mural injuries of the internal carotid artery.

Adult↗
PubMed1995

Interaction of SecB with intermediates along the folding pathway of maltose-binding protein.

SecB, a molecular chaperone involved in protein export in Escherichia coli, displays the remarkable ability to selectively bind many different polypeptide ligands whose only common feature is that of being nonnative. The selectivity is explained in part by a kinetic partitioning between the folding of a polypeptide and its association with SecB. SecB has no affinity for native, stably folded polypeptides but interacts tightly with polypeptides that are nonnative. In order to better understand the nature of the binding, we have examined the interaction of SecB with intermediates along the folding pathway of maltose-binding protein. Taking advantage of forms of maltose-binding protein that are altered in their folding properties, we show that the first intermediate in folding, represented by the collapsed state, binds to SecB, and that the polypeptide remains active as a ligand until it crosses the final energy barrier to attain the native state.

ATP-Binding Cassette Transporters↗
PubMed1995

Craniofacial trauma and cerebrospinal fluid leakage: a retrospective clinical study.

PURPOSE: The study examines the efficacy of antibiotic treatment in patients with traumatic cerebrospinal fluid (CSF) leakage and identifies a consistent clinical approach for better management of these patients. PATIENTS AND METHODS: A retrospective study of traumatic CSF leakage in 88 patients with craniofacial fractures was performed. The mechanism of injury, etiology and source of leakage, decision to treat conservatively (without surgery) versus aggressively (with surgery), decision to use early versus late repair, and decision to provide prophylactic antibiotic coverage were recorded. Both timing of repair and the decision to use antibiotics were compared with the incidence of meningitis resulting from CSF leakage. RESULTS: Of 48 patients treated with antibiotics, 5(10.4%) developed meningitis. In the remaining 40 who were not treated with antibiotics, only one patient acquired meningitis. Five of 53 (9.4%) patients with conservative treatment developed meningitis versus 1 of 35 (2.9%) after aggressive treatment. CONCLUSION: There was no statistically significant difference in the rate of occurrence of meningitis between the conservative and the aggressive treatment group. However, the data suggest that there may be no benefit in treating these patients with antibiotics to prevent meningitis, whereas aggressive treatment and early repair of facial fractures may, in fact, be helpful.

Adolescent↗
PubMed1995

The role of a substance abuse consultation team in a trauma center.

OBJECTIVE: Trauma is a leading cause of morbidity and mortality in the U.S., and substance abuse makes an enormous contribution to this problem as well as to the increased cost of health care. A substance abuse consultation (SAC) team was developed to evaluate and intervene with trauma victims who are suspected of having problems with alcohol and/or other drugs. This study was undertaken to determine the effectiveness of this service. METHOD: This study is a retrospective review of 100 consecutive trauma admissions who were felt to be at high risk for substance abuse and were referred to the SAC team for evaluation and intervention. This study was undertaken in a tertiary care teaching hospital in a cooperative effort between the trauma center and the addictions program. RESULTS: All 100 patients were diagnosed with psychoactive substance use disorders and 78 were referred for alcohol and other drug rehabilitation. Of these patients, 62% accepted a referral for drug and alcohol treatment. CONCLUSIONS: From these preliminary data, it appears that a SAC team may be effective in intervening with hospitalized trauma patients who have alcohol and other drug problems.

Accidents, Traffic↗
PubMed1994

Blunt vascular injury associated with closed mid-shaft femur fracture: a plea for concern.

During a period of six years, 765 consecutive patients were treated by the trauma service at Allegheny General Hospital for closed mid-shaft femur fractures that were a component of their injury complex. Thirty-one patients underwent angiography of the involved extremity for indications including loss of pulses in eleven and large hematomas or deformities of the thigh in the remainder. Ten patients (1.3%) were found to have acute vascular injuries. In nine patients there was an intimal flap of the superficial femoral artery (SFA), and in one, a pseudoaneurysm. Two patients had injuries of the femoral nerve. Three patients had no other associated major injuries (Injury Severity Score range, 10-19). Twelve months after the initial injury, one patient developed an arteriovenous fistula of the SFA. Detailed, repeated physical examinations, early utilization of angiography, and intensive follow-up by the trauma surgeon or orthopedic surgeon of patients with closed mid-shaft femur fractures should lead to early recognition of this potentially serious association.

Adolescent↗
PubMed1994

Enhanced rim around infarcted, traumatized spleen on computed tomographic scans: case report.

Computed tomography is considered a reliable imaging technique when determining the extent of splenic injury. We present the case of a patient with a traumatic infarct of the spleen detected by computed tomographic scanning of the abdomen. During laparotomy there was an infarction of the spleen from a hilar injury in addition to bleeding from the splenic vein. We conclude that ongoing bleeding from the splenic hilar vessel can lead to a rim of enhancement around the spleen from contrast material. This should be taken into account when a decision is made for nonsurgical management.

Abdominal Injuries↗
PubMed1994

Diving injuries: a preventable catastrophe.

During a 5-year period from January 1987 through January 1992, 58 patients were admitted to the Allegheny General Hospital trauma center for non-scuba, non-suicidal diving injuries. There were 46 men and 12 women (mean age, 23 years). Forty-five patients were injured in swimming pools. Twenty-two patients had blood alcohol levels > 100 mg/dL. Cervical spine injury was the most common pathologic entity encountered in this group of patients. Closed head injury, pelvic fracture, thoracic vertebral fracture, and rib fractures were other injuries identified. Some patients had multiple organ failure syndrome. Aquatic recreational activities carry a risk for injury that is preventable. The mechanism, clinical data, and complications of 58 patients are presented and the importance of prevention is discussed.

Adolescent↗
PubMed1994

Delayed rupture of the spleen--myths, facts, and their importance: case reports and literature review.

Over a 1-year period, three patients were seen in our trauma service with delayed bleeding (> or = 7 days) from an initially inapparent splenic injury. This entity was defined as a late occurrence of signs and symptoms attributed to splenic injury not detected by diagnostic computed tomographic (CT) scanning during the initial examination. We believe that this represents an "injury in evolution" minor enough to go undetected on initial CT scans of the abdomen. A high index of suspicion and liberal utilization of imaging techniques are essential for the identification of delayed splenic rupture. Further multicenter studies are required to delineate the true incidence of its occurrence and its clinical significance. We conclude that "delayed rupture" of the spleen is a true clinical entity. The occurrence of a delayed rupture may prove hazardous to patients discharged early from the hospital after blunt abdominal injury. A classification system to assess this type of injury is suggested.

Accidents, Traffic↗
PubMed1993

Metabolic control of sugar transport by derepression of cell surface glucose transporters. An insulin-independent recruitment-independent mechanism of regulation.

Protein-mediated sugar transport is nominally absent in normoxic pigeon erythrocytes. Following exposure to metabolic inhibitors (cyanide or carbonyl-cyanide-p-trifluoromethoxyphenylhydrazone), pigeon red cells transport sugars by a saturable stereoselective pathway that is inhibited by cytochalasin B or forskolin. The sugar transport capacity of fully poisoned cells is consistent with a transporter density of approximately 30 carriers/erythrocyte. Immunoblot analyses and competition enzyme-linked immunosorbent assay indicate that pigeon red cells contain approximately 200 copies of an integral plasma membrane protein immunologically related to the glucose transporter isoform GLUT1. GLUT1 is quantitatively restricted to the plasma membrane at all times. Pigeon red cells and brain lack proteins immunologically related to the sugar transporter isoforms GLUT3 and GLUT4. Specific immunodepletion of red cell GLUT1 content results in the subsequent loss of reconstitutable protein-mediated sugar transport. These findings demonstrate that avian erythrocyte sugar transport is mediated by a GLUT1-like sugar transport protein and that sugar transport stimulation by metabolic depletion results from derepression of cell surface sugar transport proteins.

3-O-Methylglucose↗
PubMed1993

Hypoxemia after blunt chest injury: right-to-left intracardiac shunt managed non-operatively.

A case of patent foramen ovale with right-to-left intracardiac shunt after blunt chest injury is presented. The association of pulmonary contusion, pulmonary hypertension, and patent foramen ovale in a previously healthy subject is discussed. In such a case reduction of the afterload on the right ventricle is the suggested modality of treatment for hypoxemia due to the right-to-left shunt.

Adult↗
PubMed1993

ATLS-based videotape trauma resuscitation review: education and outcome.

Trauma resuscitations (TRs) can be improved with ongoing videotape review. Unrecognized errors, delays, and system problems can be identified and corrected. Previous studies have demonstrated the importance of a short TR on survival and that videotape education can shorten TR time. Trauma resuscitation efficiency depends on details of TR including timing, organization, and appropriateness of care. Videotape education review monitors TR detail and improves TR efficiency by eliminating wasted time and treatment errors. Eight hundred eighty-three patients were evaluated. Group I included a control group prior to the incorporation of an ATLS based videotape review process. Group II included patients who were resuscitated after the educational review process was established. Subgroups based on ISS, direct OR transfer, DPL, and CT scan were also compared. Time and outcome were compared. Videotape educational review based on ATLS guidelines has improved TR efficiency. The benefits of ongoing videotape review include more efficient time utilization, correction of conceptual and technical errors, elimination of "wasted time," and improved survival.

Audiovisual Aids↗
PubMed1993

Acute obstructive uropathy secondary to pelvic hematoma compressing the bladder: report of two cases.

Two patients with traumatic retroperitoneal hematomas causing obstructive uropathy required surgical evacuation of the hematoma to relieve the obstruction. Fast recovery of renal function and an instant increase in urine output resulted. The obstruction to the urine outflow by the retroperitoneal hematoma caused near total collapse of the bladder in these patients, which was corrected by angiographic embolization and surgical removal of the hematoma.

Acute Disease↗
PubMed1993

Acute mortality associated with injuries to the pelvic ring: the role of early patient mobilization and external fixation.

PURPOSE: To analyze the effect on mortality of a protocol for early mobilization with external fixation of patients with pelvic ring injuries. METHODS: From 1981 through 1988, 605 patients with pelvic ring fractures and dislocations were treated. In 1982, a protocol for early external fixation of hemodynamically unstable patients and those with structurally unstable pelvic fracture patterns to achieve early mobilization to an upright chest position was initiated. Mortality rates were compared between 1981 (pre-protocol), 1982 (transitional), and 1983 through 1988, after initiation of a protocol of care that included external fixation of the pelvic injury. No statistical changes occurred from 1983 through 1988. RESULTS: Mortality rates in pelvic ring injury patients fell from 26% in 1981, to 6% in 1983 through 1988 (p < 0.001), whereas during the study period the mean injury Severity Score (ISS), 23, did not change. The mortality rate of a group of consecutive patients with comparable ISSs, but without pelvic ring injuries did not change. The mortality rate in patients with systolic blood pressure < 100 mm Hg at admission fell from 41% in 1981 to 21% 1983 through 1988 (p = 0.0001). Mortality in patients with closed head injuries associated with pelvic ring injuries fell from 43% in 1981 to 7% from 1983 through 1988 (p = 0.0001). The proportion of patients undergoing external fixation rose from 3% in 1981 to 31% in 1983 through 1988 (p = 0.0001). CONCLUSIONS: An organized protocol including external fixation and early patient mobilization to an upright chest position reduced mortality associated with injuries of the pelvic ring. Orthopedic stabilization of major skeletal injuries should be viewed as part of patient resuscitation, not reconstruction.

Clinical Protocols↗