Articular exposure with the swashbuckler versus a "Mini-swashbuckler" approach

OBJECTIVE

To quantify the articular exposure obtained with a Swashbuckler approach to the distal femur and compare this to a "Mini-swashbuckler" approach.

METHODS

Forty surgical approaches in 20 fresh-frozen hemipelvis specimens were performed using a Mini-swashbuckler approach followed by a traditional Swashbuckler. Key anatomic landmarks, including the posterior femoral condyles, intercondylar notch, and medial articular margin, were either directly visualised or palpated with a tonsil clamp. Calibrated digital photographs were taken from the surgeon's viewing perspective after each approach. The digital images were then analyzed using a computer software programme, ImageJ (NIH, Bethesda, MD), to calculate the articular surface square area exposed.

RESULTS

The Mini-swashbuckler exposed 87% of the articular surface compared to the Swashbuckler approach (29.48cm(2) vs 34.03cm(2), p<0.0001). Key anatomic landmarks were directly visualised with both exposures in all subjects, including limbs with severe osteoarthritis. Greater exposure with the Mini-swashbuckler correlated with male gender (p<0.05) and height (p=0.03) but not weight or BMI.

CONCLUSIONS

Although exposure is improved with the use of a Swashbuckler, this difference may not be of clinical importance, since both approaches give either direct visual or tactile access to all critical areas of the distal femur, including the trochlea, entire medial compartment, and both posterior femoral condyles. A less invasive approach allows a smaller surgical dissection without sacrificing the ability to visualise the majority of the articular surface.

Spinal column injuries among Americans in the global war on terrorism

BACKGROUND

While combat spinal injuries have been documented since the fourth century BC, a comprehensive analysis of such injuries has not been performed for any American military conflict. Recent literature has suggested that spinal injuries account for substantial disability in wounded service members.

METHODS

The Joint Theater Trauma Registry was queried to identify all American military personnel who sustained injuries to the back, spinal column, and/or spinal cord in Iraq or Afghanistan from October 2001 to December 2009. Spinal injuries were categorized according to anatomic location, neurological involvement, mechanism of injury, and concomitant wounds.

RESULTS

Of 10,979 evacuated combat casualties, 598 (5.45%) sustained 2101 spinal injuries. Explosions accounted for 56% of spinal injuries, motor vehicle collisions for 29%, and gunshots for 15%. Ninety-two percent of all injuries were fractures, with transverse process, compression, and burst fractures the most common. Spinal cord injuries were present in 17% (104) of the 598 patients. Concomitant injuries frequently occurred in the abdomen, chest, head, and face.

CONCLUSIONS

The incidence of spine trauma sustained by military personnel in Iraq and Afghanistan is higher than that reported for previous conflicts, and the nature of these injuries may be similar to those in severely injured civilians. Further research into optimal management and rehabilitation is critical for military service members and severely injured civilians with spine trauma.

Multiple associated injuries are common with spine fractures during war

BACKGROUND CONTEXT

The nature of concomitant injuries associated with spine fractures in American military personnel engaged in Operation Enduring Freedom (OEF) and Operation Iraqi Freedom (OIF) has been poorly documented in the literature.

PURPOSE

To characterize the incidence and epidemiology of associated injuries (AIs) in American military personnel with spine fractures sustained during OEF and OIF from 2001 to 2009.

STUDY DESIGN

Retrospective study.

PATIENT SAMPLE

American military personnel who were injured in a combat zone and whose medical data were abstracted in the Joint Theater Trauma Registry (JTTR).

OUTCOME MEASURES

Not applicable.

METHODS

The JTTR was queried using International Statistical Classification of Disease, Ninth Revision codes to identify all individuals who sustained spine injuries in OEF or OIF from October 2001 to December 2009. Medical records of all identified service members were abstracted to ensure accuracy and avoid duplication. Demographic information, including sex, age, and military rank, were obtained for all patients. Information regarding fracture type, spine region, mechanism of injury, and the presence of AIs was collected for all patients.

RESULTS

Seventy-eight percent of patients with a spine fracture sustained at least one AI, with an average of 3.4 AIs per patient. Musculoskeletal injuries were most common, followed by chest, abdomen, and traumatic brain injuries. Most patients were injured by an explosive mechanism (62%). Head and face traumas were more common with cervical fractures, chest with thoracic injuries, and abdominopelvic injuries with lumbosacral fractures. Pelvis and acetabulum fractures were common after helicopter crashes, tibia/fibula injuries after explosions, thoracoabdominal injuries after gunshot wounds, and traumatic brain injuries after falls. Most patients (76%) sustained multiple spine fractures.

CONCLUSION

Spine fractures sustained in OEF and OIF have high rates of AIs. Musculoskeletal AIs are the most common, but visceral injuries adjacent to the spine fracture frequently occur. Multiple spine injuries are more prevalent after military trauma.

Military penetrating spine injuries compared with blunt

BACKGROUND CONTEXT

The nature of blunt and penetrating injuries to the spine and spinal column in a military combat setting has been poorly documented in the literature. To date, no study has attempted to characterize and compare blunt and penetrating spine injuries sustained by American servicemembers.

PURPOSE

The purpose of this study was to compare the military penetrating spine injuries with blunt spine injuries in the current military conflicts.

STUDY DESIGN/SETTING

Retrospective study.

PATIENT SAMPLE

All American military servicemembers who have been injured while deployed in Iraq (Operation Iraqi Freedom) and Afghanistan (Operation Enduring Freedom) whose medical data have been entered into the Joint Theater Trauma Registry (JTTR).

METHODS

The JTTR was queried for all American servicemembers sustaining an injury to the spinal column or spinal cord while deployed in Iraq or Afghanistan. These data were manually reviewed for relevant information regarding demographics, mechanism of injury, surgical intervention, and neurologic injury.

RESULTS

A total of 598 servicemembers sustained injuries to the spine or spinal cord. Isolated blunt injuries were recorded in 396 (66%) servicemembers and 165 (28%) sustained isolating penetrating injuries. Thirty servicemembers (5%) sustained combined blunt and penetrating injuries to the spine. The most commonly documented injuries were transverse process fractures, compression fractures, and burst fractures in the blunt-injured servicemembers versus transverse process fractures, lamina fractures, and spinous process fractures in those injured with a penetrating injury. One hundred four (17%) servicemembers sustained spinal cord injuries, comprising 10% of blunt injuries and 38% of penetrating injuries (p<.0001). Twenty-eight percent (28%) of blunt-injured servicemembers underwent a surgical procedure compared with 41% of those injured by penetrating mechanisms (p=.4). Sixty percent (n=12/20) of blunt-injured servicemembers experienced a neurologic improvement after surgical intervention at follow-up compared with 43% of servicemembers (n=10/23) who underwent a surgical intervention after a penetrating trauma (p=.28). Explosions accounted for 58% of blunt injuries and 47% of penetrating injuries, whereas motor vehicle collisions accounted for 40% of blunt injuries and 2% of penetrating injuries. Concomitant injuries to the abdomen, chest, and head were common in both groups.

CONCLUSIONS

Blunt and penetrating injuries to the spinal column and spinal cord occur frequently in the current conflicts in Iraq and Afghanistan. Penetrating injuries result in significantly higher rates of spinal cord injury and trend toward increased rates of operative interventions and decreased neurologic improvement at follow-up.

Complications associated with military spine injuries

BACKGROUND CONTEXT

To assess the presence of complications associated with spine injuries in the Global War on Terror.

PURPOSE

To characterize the effect of complications in and around the battlefield during Operation Enduring Freedom and Operation Iraqi Freedom from 2001 to 2009.

STUDY DESIGN/SETTING

Retrospective study.

PATIENT SAMPLE

American servicemembers sustaining spine injury during combat.

METHODS

Extracted medical records of warriors identified by the Joint Theater Trauma Registry from October 2001 to December 2009. Complications were defined as unplanned medical events that required further intervention. Complications were classified as major or minor and further subdivided among groups, including surgical and nonsurgical management, mounted (in an armored vehicle) or dismounted at the time of injury, and blunt or penetrating trauma.

RESULTS

Major complications were encountered in 55 servicemembers (9%), and 38 (6%) sustained minor complications. Forty-four percent (n=24) of those with major complications had more than one complication. Eleven servicemembers sustained three or more complications. There were five intraoperative complications, and 50 occurred in the perioperative period. Intraoperative complications included gastrointestinal injury, dural tear, and instrument malposition. Among patients who sustained complications, precipitating spinal injuries occurred primarily in combat (n=43 [78%]) and resulted from blunt (18) or penetrating (25) mechanisms. Complications occurred in 10 (3%) of those treated nonoperatively and 45 (25%) of those receiving surgery. Complications were higher in the dismounted group (80%) as compared with those who were mounted in vehicles at the time of injury (20%). Thirty-five percent (n=24) of surgically treated, dismounted, and penetrating injured servicemembers had complications. Seventeen percent (n=8) of surgically treated and blunt injured mounted servicemembers and 20% (n=13) of dismounted servicemembers had complications. Among the dismounted and nonspinal cord-injured servicemembers, both blunt (p=.002) and penetrating injured (p<.0005) treated with surgery were correlated with complications. Only the dismounted servicemembers with spinal cord injuries because of a penetrating mechanism were also at an increased risk for complications (p<.0005).

CONCLUSIONS

Patients treated with surgery appear to be at increased complication risk regardless of the mechanism of injury. Uparmored vehicles may safeguard servicemembers from spine injuries and complications associated with their treatment. This may be reflective of the fact that less severe spinal and concomitant injuries are sustained in the precipitating trauma because of the protection afforded by the vehicle. Dismounted soldiers had more complications in all groups regardless of type of management or injury mechanism.

Are spine injuries sustained in battle truly different?

BACKGROUND CONTEXT

The severity and prognosis of combat-related injuries to the spine and spine injuries sustained unrelated to direct combat have not been previously compared. Differences may have implications on tactics, treatment strategies, and directions for future research.

PURPOSE

Compare the severity and prognosis of battle and nonbattle injuries to the spine.

STUDY DESIGN

Retrospective study.

PATIENT SAMPLE

American military personnel who were injured in a combat zone and whose medical data were abstracted in the Joint Theater Trauma Registry (JTTR).

METHODS

The JTTR was queried using International Statistical Classification of Diseases, Ninth Revision codes to identify all individuals who sustained battle and nonbattle injuries to the neck, back, spinal column, or spinal cord in Operation Iraqi Freedom or Operation Enduring Freedom from October 2001 to December 2009. Medical records of all identified servicemembers were individually reviewed. Demographic information, including sex, age, military rank, date of injury, and final disposition, was obtained for all patients. Spinal injuries were categorized according to anatomic location, associated neurologic involvement, precipitating mechanism of injury (MOI), and concomitant wounds. These data points were compared for the groups battle spine injuries (BSIs) and nonbattle spine injuries (NBSIs).

RESULTS

Five hundred two servicemembers sustained a total of 1,834 battle injuries to the spinal column, including 1,687 fractures (92%), compared with 92 servicemembers sustaining 267 nonbattle spinal column injuries, with 241 (90%) fractures. Ninety-one BSI servicemembers (18% of patients) sustained spinal cord injuries (SCIs) with 41 (45%) complete SCIs, compared with 13 (14% of patients) nonbattle SCIs with six (46.2%) complete injuries (p=.92). The reported MOI for 335 BSI servicemembers (66.7%) was an explosion compared with one NBSI explosive injury. Eighty-four patients (17%) sustained gunshot wounds (GSWs) in battle compared with five (5.2%) nonbattle GSWs. Fifteen patients (3.0%) sustained a battle-related fall compared with 29 (30%) nonbattle-related falls. Battle spine injury servicemembers underwent significantly higher rates of surgical interventions (p<.0001), were injured by high-energy injury mechanisms at a significantly greater rate (p<.0001), and demonstrated a trend toward lower neurologic recovery rates after SCI (p=.16).

CONCLUSIONS

Battle spine injury and NBSI are separate entities that may ultimately have disparate long-term prognoses. Nonbattle spine injury patients, although having similar MOIs compared with civilian spinal trauma, maintain a different patient demographic. Further research must be directed at accurately quantifying the long-term disabilities of all spine injuries sustained in a combat theater, whether they are the result of battle or not.

The effect of vehicle protection on spine injuries in military conflict

BACKGROUND CONTEXT

To evaluate the effect of critical time periods in vehicle protection on spine injuries in the Global War on Terror.

PURPOSE

To characterize the effect of method of movement on and around the battlefield during Operation Enduring Freedom and Operation Iraqi Freedom from 2001 to 2009 in terms of its impact on the incidence and severity of spinal fractures sustained in combat.

STUDY DESIGN/SETTING

Retrospective study.

PATIENT SAMPLE

Mounted and dismounted American servicemembers who were injured during combat.

METHODS

Extracted medical records of servicemembers identified in the Joint Theater Trauma Registry from October 2001 to December 2009. Methods of movement were defined as mounted or dismounted. Two time periods were compared. Cohorts were created for 2×2 analysis based on method of movement and the time period in which the injury occurred. Time period 1 and 2 were separated by April 1, 2007, which correlates with the initial fielding of the modern class of uparmored fighting vehicles with thickened underbelly armor and a V-shaped hull. Our four comparison groups were Dismounted in Time Period 1 (D1), Dismounted in Time Period 2 (D2), Mounted in Time Period 1 (M1), and Mounted in Time Period 2 (M2).

RESULTS

In total, 1,819 spine fractures occurred over the entire study period. Four hundred seventy-two fractures (26%) were sustained in 145 servicemembers who were mounted at the time of injury, and 1,347 (74%) were sustained by 404 servicemembers who were dismounted (p<.0005). The incidence of fractures in the dismounted cohort (D1+D2) was significantly higher than in the mounted cohort (M1+M2) in both time periods (D1 vs. M1, 13.75 vs. 3.95/10,000 warrior-years [p<.001] and D2 vs. M2, 11.15 vs. 4.89/10,000 warrior-years [p<.0001]). In both the mounted and dismounted groups, the thoracolumbar (TL) junction was the most common site of injury (36.1%). Fractures to the TL junction (T10-L3) increased significantly from Time Period 1 to 2 (34% vs. 40% of all fractures, respectively, p=.03). Thoracolumbar fractures were significantly more severe in that there were more Arbeitsgemeinschaft fur Osteosynthesefragen/Magerl Type A injuries versus all TL fractures, 1.75 versus 2.68/10,000 or 27% of all spine fractures in Time Period 1 versus 40% in Time Period 2 (p=.007). Furthermore, there were significantly fewer minor fractures (spinous process and transverse process fractures) (p<.0001). In Time Period 2, significantly more TL spine fractures were classified as major fractures, according to the Denis classification system, in both the mounted and dismounted groups; M1 group, 61 of 226 (27%) versus the M2 group, 86 of 246 (34%) (p<.0005) and 173 of 786 (22%) in the D1 group versus 193 of 561 (34%) in the D2 group. The spinal cord injury (SCI) incidence did not change in the mounted groups in Time Period 1 (7 of 71, 9.9%) versus Time Period 2 (7 of 74, 9.5%) (p=.935). In the dismounted groups, SCI actually decreased from D1 (55 of 228, 24%) to D2 (28 of 176, 16%) (p=.0428).

CONCLUSIONS

The incidence of spine fractures and SCI is significantly higher in dismounted operations. The data suggest that current uparmored vehicles convey greater protection against spinal fracture compared with dismounted operations in which servicemembers are engaged on foot, outside their vehicles. The TL junction is at greatest risk for spine fractures sustained in mounted and dismounted combat operations. Recently, the incidence of TL fractures, especially severe fractures, has significantly increased in mounted operations. Although there has been an increased incidence of TL spine fractures, in context of the number of servicemembers deployed in support of Operation Enduring Freedom/Operation Iraqi Freedom, these severe fractures still represent a relatively rare event.

Do plans and execution agree in a humanitarian medical mission?

There is a significant need for orthopaedic care in developing countries. For the past 10 years, the United States Army has supported annual orthopaedic hand surgery humanitarian missions to Honduras. The goal of this article is to compare the premission planning to the realities of mission execution to provide a template for future missions. Premission planning began 1 year before the mission. Based on previous missions, supplies were brought for 50 surgical cases. The mission began with 1 preoperative clinic day followed by 8 operative days and 1 postoperative clinic day. Of the 99 prescreened patients, 65 were indicated for surgery. A total of 58 surgeries were performed using innovative methods to stretch available supplies. A multidisciplinary and multination concerted effort is required for a successful humanitarian medical mission. A premission plan is critical prior to arrival and a contingency plan must be in place for missing mission-critical items.

Comparison of dorsal and volar approaches to the proximal radius

Proximal radius exposure may be acquired by either the dorsal or volar approach depending on surgical requirements. The dorsal approach is traditionally recommended for fracture fixation of the proximal radius because of theoretically improved exposure and because the dorsal aspect of the bone is the tensile surface. The posterior interosseous nerve can be visualized and protected using this approach. The volar approach is preferred for biceps repair and boasts a distal extensile approach with adequate soft tissue coverage. Impingement on the bicipital tuberosity and biceps tendon, in addition to positioning on the compression side of the bone, makes the anterior or anterolateral position for plate placement less desirable. The goal of this study was to quantify and compare in a cadaver model the area of bone exposed using both approaches. We hypothesized that equivalent exposures can be obtained and the posterior interosseous nerve can be identified with either the Thompson or Henry approach. Standard dorsal and volar approaches were performed on 10 fresh-frozen adult cadaveric upper-limb specimens. Cross-sectional area of exposure was quantified from digital photographs using software. The 2 approaches did not result in a significant difference in area exposed. Depending on case requirements, either the dorsal or volar approach will provide adequate exposure to the proximal radius.

Can an ankle-foot orthosis change hearts and minds?

The current military conflicts of Operation Enduring Freedom and Operation Iraqi Freedom have been characterized by high-energy explosive wounding patterns, with the majority affecting the extremities. While many injuries have resulted in amputation, surgical advances have allowed the orthopaedic surgeon to pursue limb salvage in the face of injuries once considered unsalvageable. The military limb salvage patient is frequently highly active and motivated and expresses significant frustration with the slow nature of limb salvage rehabilitation and continued functional deficits. Inspired by these patients, efforts at this institution began to provide them with a more dynamic orthosis. Utilizing techniques and technology resulting from cerebral palsy, stroke, and amputation research, the Intrepid Dynamic Exoskeletal Orthosis was created. To date, this device has significantly improved the functional capabilities of the limb salvage wounded warrior population when combined with a high-intensity rehabilitation program. Clinical and biomechanical research is currently underway at this institution in order to fully characterize the device, its effect on patients, and what can be done to modify future generations of the device to best serve the combat-wounded limb salvage population.

Sustained release of insulin from sodium hyaluronate based dry powder formulations after pulmonary delivery to beagle dogs

Hyaluronic acid (HA) and recombinant human insulin were co-spray dried to form a dry powder suitable for inhalation (Mass Median Aerodynamic Diameter, MMAD=1 to 4 microm). Insulin systemic levels and corresponding glucose levels were monitored following administration of the microparticles to the lungs of male Beagle dogs. Release kinetics were modified by addition of excess zinc ions (Zn2+) or hydroxypropyl cellulose (HPC). HA formulations containing insulin (10%w/w) were found to extend the mean residence time (MRT) and terminal half-life (t(1/2)) when compared to spray dried pure insulin. Addition of Zn2+ also improved MRT (>9 fold), AUC/dose (2.5 fold) and Tmax (by a factor of 3) when compared to spray dried pure insulin. Addition of HPC improved MRT (>7 fold), AUC/dose (5 fold) and Tmax (by a factor of 3) when compared to spray dried pure insulin. Our results demonstrate the potential of HA-based dry powder drug delivery systems in the pulmonary controlled release of insulin.

Modifying the release of leuprolide from spray dried OED microparticles

A range of oligosaccharide ester derivatives (OEDs) have been designed as drug delivery matrices for controlled release. The synthetic hormone analogue, leuprolide, was encapsulated within these matrices using hydrophobic ion pairing and solvent spray drying. The particles produced modified the release of leuprolide in vitro (dissolution in phosphate buffered saline) and in vivo (subcutaneous and pulmonary delivery in the rat). Release rate was dependent on drug loading and could be manipulated by choice of OED and by combining different OEDs in different ratios. Leuprolide encapsulated in the OEDs retained biological activity as evidenced by elevation in plasma luteinising hormone levels following subcutaneous injection of leuprolide recovered from OED particles in vitro prior to in vivo administration.

Early predictors of myoglobinuria and acute renal failure following electrical injury

Myoglobinuria-induced acute renal failure (ARF) is a potentially lethal consequence of electrical injury. We describe clinical variables that can predict the risk of myoglobinuria and ARF following electrical injury. This was a retrospective multivariate analysis of risk factors among electrically injured patients over a 26-year period. Urine myoglobin status was documented in 162 patients; 14% had myoglobinuria. No patient developed ARF. Multivariate modeling revealed that high-voltage exposure, prehospital cardiac arrest, full-thickness burns, and compartment syndrome were associated with myoglobinuria. Using a prediction rule defined as positive when a patient had > or = 2 risk factors yielded a sensitivity of 96% and negative predictive value of 99%. Electrical injury patients with myoglobinuria have little risk of developing ARF. A prediction rule can be used to screen out patients at low risk for myoglobinuria and identify high-risk patients who warrant early aggressive treatment and a more definitive myoglobin test.

Mechanisms of pediatric electrical injury. New implications for product safety and injury prevention

OBJECTIVES

To determine age-specific mechanisms of electrical injury in children, to examine product safety regulation of the major sources of electrical injury hazard, and to assess the adequacy of current prevention strategies.

DESIGN

Case series of 144 pediatric and adolescent electrical injuries in patients seen in the specialized burn center and tertiary care hospital between 1970 and 1995, examination of Consumer Product Safety Commission product recall reports for electrical injury hazards between 1973 and 1995, and review of the National Electric Code.

RESULTS

Eighty-six cases of electrical injuries resulted from low-voltage (< 1000-V) exposures, all occurring within the home. In children aged 12 years and younger, household appliance electrical cords and extension cords caused more than 64 (63%) of 102 injuries, whereas wall outlets were responsible for only 14 (15%) of injuries. Fifty-eight cases resulted from high-voltage exposures, accounting for 38 (90%) of 42 injuries in children older than 12 years. No federal safety regulations for electrical cords exist, although voluntary standards have been adopted by many manufacturers. Among 383 consumer products identified by the Consumer Product Safety Commission to be electrical injury hazards, 119 were appliance cords, extension cords, or holiday stringed light sets. Several products numbered more than 1.5 million units in US household distribution prior to the investigation by the Consumer Product Safety Commission.

CONCLUSIONS

Household electrical cords are the major electrocution hazard for children younger than 12 years, yet no federal safety mandates exist. Despite voluntary standards, noncompliant manufacturers can introduce vast numbers of unsafe cords onto the US household market every year. Conversion of existing voluntary safety guidelines into federally legislated standards may be the most effective intervention against pediatric electrocutions.

Mechanisms of aluminum absorption in rats

Aluminum has become a dietary toxin in modern times but its mechanism of absorption is poorly understood. After ingestion, the systemic transfer of aluminum is small but it is greatly affected by the coingestion of certain dietary agents, such as citrate, that complex with the metal in the intestinal lumen or transiently alter the permeability of the mucosa. Here, mechanisms of aluminum absorption were studied by using freshly prepared aluminum hydroxide and aluminum citrate. Everted sacs of rat gut were used to investigate the site of absorption, effect of chemical charge on absorption of aluminum citrate, and presence of active or passive absorption with use of the metabolic inhibitor ouabain. Absorption was biphasic with a large tissue uptake that was consistent with adhesion to mucus-mucosal surface but little tissue transport, which was consistent with passive paracellular permeation. Citrate reduced the uptake-transport ratio both by competing with the mucosal uptake and by increasing mucus-mucosal permeation but not by affecting the charge of the luminal aluminum species. Despite the potential for hydroxypolymerization of aluminum at intestinal pH, the small bowel and colon absorbed aluminum passively and paracellularly but the stomach did not. The predominantly proximal absorption of aluminum observed in vivo is a reflection of the proximal absorption, and therefore removal, of dietary constituents (eg, citrate) that enhance mucosal permeation of aluminum. The colon should be investigated further as a site of significant paracellular permeability.

Gallium-transferrin binding in treated and untreated Parkinson's disease

The binding of gallium (Ga) to transferrin (Tf) was studied in plasma from control patients, in patients with untreated Parkinson's disease (PD) and in patients with PD treated either with levodopa (L-dopa) alone or in combination with selegiline. Mean percentage Ga-Tf binding was significantly reduced in untreated and treated PD compared with controls. Binding, however, was significantly greater in treated than in untreated patients. There was no difference in binding between patients treated with L-dopa alone and those treated with L-dopa and selegiline. The data support the hypothesis that oxidation reactions may be of pathogenic significance in PD.

Aluminium and Alzheimer's disease: review of possible pathogenic mechanisms

Chronic exposure to aluminium (Al) remains a controversial possible cause of sporadic forms of Alzheimer's disease (AD). This article reviews the evidence that once Al enters the brain and individual brain cells, it may be involved in three pathological processes: (1) the production of abnormal forms of tau leading to the formation of cellular neurofibrillary tangles and neuropil threads; (2) the processing of the amyloid precursor protein, resulting in the formation of beta-amyloid deposits and senile plaques, and (3) that via the mutual histocompatibility system, Al could be involved in the initiation of the immune response observed in AD patients. Despite recent evidence that Al could be involved in these processes, a conclusive case that exposure to Al initiates the primary pathological process in sporadic AD remains to be established.

The role of pterins in depression and the effects of antidepressive therapy

Urinary excretion of neopterins (N) and biopterins (B) was measured in 48 patients with depression before and after treatment with placebo, antidepressants, or electroconvulsive therapy (ECT), and in 26 healthy control subjects. Patients prior to and after treatment had a significantly greater neopterin/biopterin (N:B) ratio than control subjects. There was a significant correlation between N:B ratios and the severity of depression and plasma cortisol. As a raised N:B ratio implies failure to convert neopterin to biopterin, it is possible that reduced availability of tetrahydrobiopterin, the essential cofactor for the formation of noradrenaline, serotonin and dopamine, may exert rate-limiting control over the synthesis of monoamines implicated in the pathogenesis of depressive illness.

Hypothesis: is Alzheimer's disease a metal-induced immune disorder?

A hypothesis that a metal-induced immune disorder may be involved in the pathogenesis of some forms of Alzheimer's disease (AD) is presented. The classical complement pathway is activated in AD and T cells and reactive microglia appear in the brain. Studies of metal induced autoimmunity and the use of compounds containing aluminium as vaccine adjuvants suggest that metals can activate complement and can be taken up by antigen presenting cells. The consequent immune response could contribute to neuronal damage, beta-amyloid deposition and cell death. The strengths and weaknesses of this hypothesis are discussed and tests of some aspects are proposed.

5-Methyltetrahydrofolate level in the serum of depressed subjects and its relationship to the outcome of ECT

Serum 5-MeTHF levels are reported in 26 subjects, before and after completing a course of ECT, and compared to 21 healthy volunteers. 5-MeTHF levels of depressed subjects were significantly lower than controls before and after ECT. There was no difference in 5-MeTHF levels between ECT responders and non-responders but folate deficiency was related to severity of depression before ECT. Serum 5-MeTHF was not related to treatment response and values remained markedly low even after a good response to treatment.

Recovery from depression after electroconvulsive therapy is accompanied by evidence of increased tetrahydrobiopterin-dependent hydroxylation

Serum phenylalanine and tyrosine levels were measured in 26 patients with severe depression before and after receiving electroconvulsive therapy. The phenylalanine:tyrosine [P:T] ratio declined significantly for those responding to treatment but not for nonresponders. These findings are discussed in relation to tetrahydrobiopterin, the essential cofactor for the formation of noradrenaline, dopamine and serotonin and the hydroxylation of phenylalanine to tyrosine.

Pre-injury emotional trauma and chronic back pain. An unexpected finding

STUDY DESIGN

A retrospective study investigated pre-injury emotional trauma in out-of-work, blue collar patients with chronic back pain (N = 27) who participated in a 30-hour workshop in which a wide range of cognitive skills was taught to help patients with rehabilitation and return them to work.

OBJECTIVES

This study identified categories of pre-injury emotional trauma, calculated summary statistics, and performed category comparisons.

METHODS

The categories of abandonment, emotional abuse, physical abuse, and sexual abuse emerged from the data. Frequencies and percentages in each category were calculated. Chi-square tests compared the differences in emotional trauma and gender.

RESULTS

Statistically more patients reported abandonment and emotional abuse than physical and sexual abuse. There were no differences in trauma rates by gender. The results of the study revealed a high rate of pre-injury emotional trauma in patients with chronic back pain.

CONCLUSION

Including pre-injury emotional trauma in psychologic evaluations of patients with chronic back pain and high psychologic test scores is recommended.

Reduced transferrin binding in Down syndrome: a route to senile plaque formation and dementia

Plasma transferrin binding in Down syndrome and Alzheimer's disease is significantly reduced compared with age matched controls and it was thought this may help elucidate a pathological time sequence for the onset of dementia in Down syndrome. In Down syndrome, there was a reduction in gallium and aluminium transferrin binding both with age and the onset of dementia. Non-transferrin bound gallium species were identified as non-transportable phosphate or silicate. Thus, the route of entry of metals into the brain must be via a transferrin mediated complex only. A clear sequence of pathological events has been demonstrated in Down syndrome which shows the pathway to development of plaques and dementia and this is believed to have an immunological origin.

Pterin metabolism in depression: an extension of the amine hypothesis and possible marker of response to ECT

Urinary excretion of neopterins and biopterins was measured in 23 patients with severe depression before and after receiving electroconvulsive therapy (ECT) and 26 healthy control subjects. Patients with psychotic depression and those responding to ECT had neopterin:biopterin (N:B) ratio significantly higher than controls before commencing ECT and positive therapeutic response was associated with reduction of N:B ratio towards control values. As a raised N:B ratio implies failure to convert neopterin to biopterin it is possible that reduced availability of tetrahydrobiopterin, the essential cofactor for the formation of noradrenaline, serotonin and dopamine, may exert rate limiting control over the synthesis of monoamines implicated in the pathogenesis of depressive disorders. The N:B ratio may be a marker for certain depressive subtypes and response to ECT.