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Biomedical subjects

D B Michael

Publications and source records attributed to D B Michael.

At least 19 recordsLinked to original sources
PubMed2003

Measurement of free fatty acids in cerebrospinal fluid from patients with hemorrhagic and ischemic stroke.

Free fatty acid (FFA) concentrations in cerebrospinal fluid (CSF) from patients with ischemic and hemorrhagic stroke (n=25) and in contemporary controls (n=73) were examined using HPLC. Concentrations of CSF FFAs from ischemic and hemorrhagic stroke patients obtained within 48 h of the insult were significantly greater than in control patients. Higher concentrations of polyunsaturated fatty acids (PUFAs) in CSF obtained within 48 h of insult were associated with significantly lower (P<0.05) admission Glasgow Coma Scale scores and worse outcome at the time of hospital discharge, using the Glasgow Outcome Scale (P<0.01).

Chromatography, High Pressure Liquid↗
PubMed2000

Anticonvulsant prophylaxis and timing of seizures after aneurysmal subarachnoid hemorrhage.

OBJECTIVE: There is no evidence that seizure prophylaxis is indicated after aneurysmal subarachnoid hemorrhage (SAH). This study examines prophylactic antiepileptic drug (AED) prescription and the occurrence of seizures within a single university-affiliated institution. METHODS: The authors reviewed 95 SAH patient charts using standardized forms. Variables included prophylaxis duration, seizure incidence and timing, CT findings, AED adverse events, and 1-year patient follow-up. RESULTS: Prehospital seizures occurred in 17.9% (17/95) of patients; another 7.4% (7/95) had a questionable prehospital seizure. In-hospital seizures occurred in 4.1% (4/95) of patients, a mean of 14.5 +/- 13.7 days from ictus; three of these four patients were receiving an AED at the time of seizure. Inpatient AED were prescribed to 99% of the cohort for a median of 12 (range 1 to 68) days. Approximately 8% of the cohort had posthospital discharge seizures; this included the patients who had prehospital or in-hospital seizures, 50% of whom were receiving AED therapy at the time of the seizure. Adverse effects occurred in 4. 1%; none were serious. The thickness of cisternal clot was associated with having a seizure; no other clinical predictors were identified. Having a seizure at any time did not adversely affect outcome. CONCLUSIONS: In this SAH population, the majority of seizures happened before medical presentation. In-hospital seizures were rare and occurred more than 7 days postictus for patients receiving AED prophylaxis. The vast majority of putative clinical predictors did not help predict the occurrence of seizures; only the thickness of the cisternal clot was of value in predicting seizures. Patient selection for and the efficacy and timing of AED prophylaxis after SAH deserve prospective evaluation.

Adult↗
PubMed2000

An unusual subdural empyema: case report.

Subdural empyema in a 38-year-old patient with congenital hemangioma, suppurative parotitisis, soft tissue phlegmonia and osteomyelitis is reported. The clinical, radiological and surgical features are outlined. A review of the literature reveals the uniqueness of this case.

Adult↗
PubMed2000

Post-traumatic hydrocephalus.

The syndrome of post-traumatic hydrocephalus (PTH) has been recognized since Dandy's report in 1914. The incidence of symptomatic PTH ranges from 0.7%-29%. If CT criteria of ventriculomegaly are used the incidence has been reported to be from 30%-86%. Differences in diagnostic criteria and classification have contributed to the variation in reported incidence. The diagnosis of PTH is established using a combination of clinical, imaging and physiologic data. Symptomatic PTH is to be distinguished from post-traumatic ventriculomegaly resulting from atrophy. Symptomatic PTH patients are likely to improve when treated by shunting. Ventriculomegaly secondary to atrophy is less likely to respond to shunting. A series of traumatic brain injury patients at Wayne State University has been followed since 1989. The overall incidence of shunt placement in this group is 3.65%. Future studies of PTH should be aimed at refining diagnostic classification and criteria. Analysis of a large PTH population may then identify alterable risk factors in the early post-traumatic brain injury period. Minimizing these factors will help prevent subsequent PTH and obviate the need for shunting.

Brain Injuries↗
PubMed2000

The relationship of blunt head trauma, subarachnoid hemorrhage, and rupture of pre-existing intracranial saccular aneurysms.

Patients with a history of closed head trauma and subarachnoid hemorrhage are uncommonly diagnosed with an intracranial saccular aneurysm. This study presents a group of patients in whom a pre-existing aneurysm was discovered during work-up for traumatic subarachnoid hemorrhage. Without an accurate pre-trauma clinical history, it is difficult to define the relationship between trauma and the rupture of a pre-existing intracranial saccular aneurysm. We retrospectively reviewed 130 patients who presented to Detroit Receiving Hospital between 1993 and 1997 with a diagnosis of subarachnoid hemorrhage (SAH). Of these 130 patients, 70 were spontaneous, and 60 had a history of trauma. Mechanisms of trauma include motor vehicle accident, assault, or fall from a height. Of the 60 patients with subarachnoid hemorrhage and a history of trauma, 51 (86%) did not undergo conventional four-vessel angiography, and had no further neurological sequelae. Nine patients (14%) had a suspicious quantity of blood within the basal cisterns or Sylvian fissure and had a four-vessel angiogram. Five patients (8%) were diagnosed with a saccular intracranial aneurysm, and all underwent surgical clipping of the aneurysm. We conclude that the majority of patients (92%), with post-traumatic SAH do not harbor intracranial aneurysms. However, during initial evaluation, a high level of suspicion must be entertained when post-traumatic subarachnoid hemorrhage is encountered in the basal cisterns or Sylvian fissure, as 8% of our population were diagnosed with aneurysms.

Adult↗
PubMed2000

Infection related to intracranial pressure monitors in adults: analysis of risk factors and antibiotic prophylaxis.

OBJECTIVE: Infection is a complication related to intracranial pressure monitoring devices. The timing, duration, and role of prophylactic antimicrobial agents against intracranial pressure monitor (ICPM) related infection have not previously been well defined. Risk factors and selection, duration, and timing of antibiotic prophylaxis in patients with ICPMs were evaluated. METHODS: Records of all consecutive patients who underwent ICPM insertion between 1993 and 1996 were reviewed. Patients included were older than 12 years with an ICPM placed for at least 24 hours. Exclusion criteria consisted of ICPM placed before admission or documented CSF infection before or at the time of insertion. Standard criteria were applied to all patients for diagnosis of CSF infection. RESULTS: A total of 215 patients were included, 16 (7.4%) of whom developed CSF infection. Antibiotic prophylaxis for ICPM placement was administered to 63% of infected and 59% of non-infected patients. Vancomycin (60%) and cefazolin (34%) were used most often. Sixty per cent (6/16) of patients who developed infection and 45% (53/199) of those without CSF infection received their first antibiotic dose within the 2 hours before ICPM insertion. Risk factors for CSF infection included duration of monitoring greater than 5 days (RR 4.0 (1.3-11.9)); presence of ventriculostomy (RR 3.4 (1.0-10.7)); CSF leak (RR 6.3 (1.5-27.4)); concurrent systemic infection (RR 3.4 (1.2-9.5)); or serial ICPM (RR 4.9 (1. 7-13.8)). CONCLUSIONS: Administration of antibiotics to patients before or at the time of ICPM placement did not decrease the incidence of CSF infection. Patients found to be at greater risk for infection at our institution included duration of ICPM greater than 5 days, use of ventricular catheter, CSF leak, concurrent systemic infection, or serial ICPM.

Adult↗
PubMed2000

Adult rhombencephalosynapsis. Case report.

Rhombencephalosynapsis (RS) is a relatively rare developmental disorder of the cerebellum in which the cerebellar hemispheres are fused across the midline without being separated by a cleft or the vermis. The condition may be associated with hydrocephalus and other intracranial and extracranial abnormalities. The authors report on the case of a symptomatic adult who was successfully treated with suboccipital decompression and duraplasty. A 39-year-old woman presented with intractable pain radiating from the thoracolumbar column to the occiput. A general examination yielded normal findings and a neurological examination revealed only subtle ataxia of tandem gait. The patient underwent magnetic resonance (MR) imaging, the results of which revealed an absent cerebellar vermis with fusion of the cerebellum and mild hydrocephalus. A cine-MR image obtained to evaluate her cerebrospinal fluid flow (CSF) revealed attenuated flow in the posterior fossa and cerebral aqueduct. Preoperative intracranial pressure (ICP) monitoring demonstrated no elevation of ICP (mean 4.3 mm Hg). The patient consented to undergo suboccipital craniectomy and duraplasty. Despite an increase in postoperative ICP (mean 10.77 mm Hg; difference from preoperative level according to a t-test, p = 0.002), the patient experienced symptomatic relief, which has persisted for 3 years. One year postoperatively, a cine-MR image was obtained, which revealed improvement in the patient's CSF dynamics. The authors conclude that, although RS may cause altered flow in the adult, their patient has experienced symptomatic relief, suggesting that her pain was related to local pressure in the posterior fossa.

Adult↗
PubMed1999

Patterns of immediate early gene mRNA expression following rodent and human traumatic brain injury.

Cell stimulation which leads to degeneration triggers a prolonged wave of immediate early gene (IEG) transcription that correlates with neuronal demise. In order to determine the relevance of the prolonged IEG response to human traumatic brain injury, we analyzed IEG mRNA levels in brain tissue isolated following a controlled penetrating injury and an injection of the excitotoxin Quinolinic acid (QA), as well as from tissue recovered during routine neurosurgery for trauma. Total RNA was extracted from tissue and subjected to Northern analysis of IEG mRNAs (c-fos and zif/268). Both models produced rapid and prolonged waves of IEG transcription that appeared to correlate with the severity of injury. Increases in zif/268 mRNA were observed within 1 h with levels reaching their peak at 6 h following excitotoxic injury and 3 h following a controlled penetration. In general, human traumatic brain injury resulted in variable increases in IEG mRNA levels following traumatic injury with the largest IEG mRNA increases observed in tissue collected 0-10 h after injury. This post-injury time corresponds to the peak of the prolonged IEG response observed in rodents following excitotoxic injury. Comparisons were made in IEG response between rodent frontal cortex and human cortex, because the majority of the human tissue originated from the cerebral cortex. These results further support the hypothesis that prolonged IEG transcription serves as a marker of traumatic brain injury and may play a role in neurodegeneration and/or glial activation. Moreover, observations of similar IEG patterns of expression reinforces the importance of rodent models of brain injury providing useful information directly applicable to human brain injury.

Animals↗
PubMed1999

Incidence of intracranial bullet fragment migration.

Migration of retained bullets or bullet fragments may present as a complication of gunshot wounds to the head. This phenomenon has been reported in cases of abscess formation or retained copper fragments. Management of such migratory fragments is controversial. The purpose of this study is to determine the incidence of fragment migration in a population of neurosurgical patients treated for gunshot wounds to the head. Two-hundred and thirteen cases treated at Detroit Receiving Hospital between 1985 and 1987 were reviewed. Each patient treated had initial and one week follow-up imaging studies. Nine cases of documented migratory intracranial bullet fragments were identified. Thus, the incidence in this population is 4.2%. The fragments in eight cases were composed of copper, and in the remaining case, lead. No case was associated with an abscess. Fragments in the anterior fossa were found to migrate towards the sella turcica, while those of the middle fossa and posterior hemispheres migrate towards the confluence of sinuses (Torcula Herophili). Fragment migration was documented as early as 36 h post-injury. Based on this study, we recommend serial imaging studies to look for migrating bullet fragments and surgical removal aided by intra-operative ultrasound to localize the fragment when possible.

Adult↗
PubMed1998

Cerebral monitoring devices: analysis of complications.

The use of indwelling cerebral monitoring devices (ICMDs) is common in the intensive care of neurosurgical patients. ICMDs are used to measure and treat intracranial pressure (ICP), temperature, blood flow and the microchemical environment. Intracranial hemorrhage (ICH) and infection are risks of ICMD use [4]. This study presents ICMD use at Detroit Receiving Hospital (DRH) from July 1993- March 1997. Analysis of complications associated with ICMD placement will test the hypothesis that complication rate depends upon type of ICMD used. A log of all patients having ICMDs at DRH has been kept since 1993. This log was used to identify complications of ICMD placement. Each case was reviewed and the following data obtained: diagnosis, patient age, initial Glasgow Coma Score, Glasgow Outcome Score, type of ICMD, number of ICMDs per patient, duration of implant and complication. Descriptive and non-parametric statistics were used to compare samples of interest. The following number of ICMDs were placed: 274 ventriculostomies, 229 Camino intra parenchymal ICP monitors, and 33 other ICMDs. Complications in these 536 cases include 21 infections, 15 ICHs, 1 granuloma and 1 persistent cerebrospinal fluid leak. Complication was analyzed as a function of ICMD type using Chi-Square test for independence. The rate of infection and ICH was significantly higher in the ventriculostomy group (p = 0.0001). These results support the hypothesis that complications of ICMD use are due to the type of device implanted. The determinants of ICMD complication is undoubtedly multifactorial. The clinician must consider the complication rate related to a particular ICMD among other factors when choosing to place an ICMD.

Brain Injuries↗
PubMed1998

Patterns of heat-shock protein 70 biosynthesis following human traumatic brain injury.

Heat-shock protein 70 (hsp70) is activated upon cellular stress/injury and participates in the folding and intracellular transport of damaged proteins. The expression of hsp70 following CNS trauma has been speculated to be part of a cellular response which is involved in the repair of damaged proteins. In this study, we measured hsp70 mRNA and protein levels within human cerebral cortex subjected to traumatic brain injury. Specimens were obtained during routine neurosurgery for trauma and processed for Northern mRNA and Western protein analysis. The largest increase in hsp70 mRNA levels was detected in trauma tissue obtained 4-6 h following injury. By 24 h, hsp70 mRNA levels were similar to nontrauma comparison tissues. hsp70 protein expression exhibited its greatest increases at 12-20 h post-injury. Immunocytological techniques revealed hsp70 protein expression in cells with neuronal-like morphology at 12 h after injury. These results suggest a role for hsp70 in human cortex following TBI. Moreover, since the temporal induction pattern of hsp70 biosynthesis is similar to that reported in the rodent, our observations validate the importance of rodent brain injury models in providing useful information directly applicable to human brain injury.

Blotting, Northern↗
PubMed1998

Heat-shock protein 72 expression in excitotoxic versus penetrating injuries of the rodent cerebral cortex.

The induction of heat shock protein 72 (hsp72) has been described in various experimental models of brain injury. The present study examined hsp72 expression patterns within the rodent cerebral cortex in experimental paradigms designed to mimic two mechanisms of damage produced by penetration of the cerebral cortex: (1) tissue tearing from the missile track and (2) diffuse excitotoxicity during temporary cavitation and shock wave formation. Adult male Spaque-Dawley rats received controlled penetration (stab) or injection of the NMDA receptor excitotoxin, quinolinic acid (QA), into the frontal cortex and were killed 1-24 h later. Tissue from the lesioned, sham-operated, or contralateral uninjected cortex was processed for Western and immunocytochemical analyses of hsp72 protein expression. By 12 h, both controlled penetration and excitotoxic brain injuries produced significant increases in hsp72 immunoreactivity, which decreased toward control levels at 24 h. However, the severity and regional distribution of hsp72 expression varied between the two models. Specifically, the controlled penetration injury produced many hsp72-expressing cells near the needle track, while immunoreactive cells within the QA-injected cortex were found in the periphery of the lesion site. Morphological assessment of brain sections subjected to dual-labeling procedures demonstrated that cells expressing hsp72 were primarily neuronal in both models of injury. These results suggest that although controlled penetration and diffuse excitotoxicity may induce similar temporal and cellular patterns of hsp72 expression, the spatial location of hsp72-immunoreactive cells may differ between the two models.

Animals↗
PubMed1998

A cohort study of the safety and feasibility of intraventricular urokinase for nonaneurysmal spontaneous intraventricular hemorrhage.

BACKGROUND AND PURPOSE: Small case series have reported potential benefit from thrombolysis after spontaneous intraventricular hemorrhage (IVH). Our objective was to review our experience using intraventricular urokinase (UK) in treating selected patients with IVH. METHODS: Using medical records, we identified all patients who received ventriculostomies for CT-confirmed nonaneurysmal nontraumatic spontaneous IVH from December 1992 through November 1996. We reviewed charts and CT images and examined the data for associations with specific outcomes. RESULTS: We identified 40 patients, 18 treated with ventriculostomy alone and 22 receiving adjunctive intraventricular UK. The initial Glasgow Coma Scale (GCS) scores of the two groups were similar (P = 0.5). While there was a trend for patients with any intraparenchymal hemorrhage (IPH) to receive UK (P = 0.07), the mean size of IPH in those who received ventriculostomy alone was larger than in those who received adjunctive UK (P = 0.002). There was lower mortality in the group treated with UK (31.8 versus 66.7%; P = 0.03), but there was only a trend toward an increase in favorable outcome (22.2% versus 36.4%; P = 0.3). Overall, the most significant association with outcome was neurological condition at presentation (GCS >5 versus < or = 5; P = 0.003). Receiving UK did not increase the occurrence of complications or hospital length of stay for survivors (P = 0.5). CONCLUSIONS: Intraventricular UK remains a safe and potentially beneficial intervention. While it appeared to lower mortality, a randomized, placebo-controlled trial is needed to explore whether the therapy can increase the incidence of favorable outcomes.

Adult↗
PubMed1989

Innervation of the pituitary gland by supraependymal neurons.

Retrograde transport of horseradish peroxidase (HRP) was used to identify supraependymal neurons projecting to the pituitary gland in the hamster. Supraependymal neurons overlying the median eminence were labeled by HRP injections into the neural and intermediate lobes of the pituitary gland; no neurons were labeled following HRP injections confined to the anterior lobe. Supraependymal neurons innervating the pituitary gland may provide a means whereby cerebrospinal fluid-borne substances modulate neuro-intermediate lobe function.

Animals↗
PubMed1989

Coincidence of head and cervical spine injury.

The association of head and cervical spine injury has long been recognized. Reports of the coincidence of these injuries in the literature range from 1.2 to 19%. This study was undertaken to determine the coincidence and examine the mechanisms of head and cervical spine injuries at a major trauma hospital. All cases of cervical spine injury (CSI) and head injury (HI) admitted to The Detroit Receiving Hospital during 1987 were identified using the hospital computer data bank and spine unit log book. There were 359 admissions for CSI including concussion, skull fracture, and intracranial hemorrhage. There were 92 admissions for CSI including complete or incomplete neurologic syndromes with fractures. There were 22 patients with both HI and CSI. Thus the coincidence of "primary" CSI with HI (both/CSI) is 24% while the coincidence of primary HI with CSI (both/HI) is 6%. The variety of injuries is demonstrated with appropriate imaging studies. Our study supports the view that all seriously head-injured patients should be treated as if a concomitant cervical spine injury is present until proven otherwise. It also shows that nearly one-quarter of patients with cervical spine injury have also experienced head injury. This coincidence may be an important consideration in the rehabilitation of such injured patients.

Accidents, Traffic↗
PubMedDate not supplied

Gene expression in neurotrauma.

It has been established that following injury to the central nervous system two types of damage take place, the initial insult and the secondary response to injury. This review will focus on the secondary molecular aspects of neurotrauma. These responses may be either deleterious or have protective effects upon the injured cell population. Molecular responses include the regulation of genes which change cellular architecture, up-regulate of growth factors, induce reparative stress responses, influence apoptosis and regulate the transcriptional process. The purpose of this study is to provide the reader with a brief overview of some of the molecular mechanisms which are activated following a neurological insult.

Animals↗