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Biomedical subjects

L H Pitts

Publications and source records attributed to L H Pitts.

At least 55 records · Page 3Linked to original sources
PubMed1992

Prognosticators of outcome after major head injury in the elderly.

In 195 elderly head-injured patients, Glasgow Coma Scale (GCS) scores (admission and 72 hours) and intracranial pressure (ICP) 0-12 days after injury were compared to 6 month Glasgow Outcome Scores. All patients remaining comatose at least 72 hours after injury died within 6 months. The mortality rate among patients with ICP greater than 20 mm Hg was higher both at 72 hours and at 6 months after injury. The 6 month mortality rate was 75% overall and 90% among patients with elevated ICP. This increased mortality in elderly patients with initially elevated ICP indicates that nurses and other health professionals should consider ICP as well as level of consciousness when counseling patients and families regarding the likely outcome after major head injuries.

Age Factors↗
PubMed1992

Decompression of the optic nerve sheath for vision-threatening papilledema caused by dural sinus occlusion.

Obstruction of the dural sinuses produces a clinical syndrome that resembles pseudotumor cerebri. In these patients, unremitting papilledema can cause blindness. We performed decompression of the optic nerve sheath in four patients who had occlusion of the dural sinuses. The operation achieved rapid relief of papilledema and recovery of vision. In three patients, fenestration of the nerve sheath of only one eye resulted in resolution of papilledema in both eyes. The procedure appears to relieve papilledema by filtering small quantities of cerebrospinal fluid into the orbit. It did not lower cerebrospinal fluid pressure in three patients who underwent lumbar puncture after surgery. Optic nerve sheath decompression is an effective operation for salvage of vision in patients with obstruction of the dural sinuses.

Adult↗
PubMed1992

Analysis of chromosome 22 deletions in neurofibromatosis type 2-related tumors.

The neurofibromatosis type 2 (NF2) gene has been hypothesized to be a recessive tumor suppressor, with mutations at the same locus on chromosome 22 that lead to NF2 also leading to sporadic tumors of the types seen in NF2. Flanking markers for this gene have previously been defined as D22S1 centromeric and D22S28 telomeric. Identification of subregions of this interval that are consistently rearranged in the NF2-related tumors would aid in better defining the disease locus. To this end, we have compared tumor and constitutional DNAs, isolated from 39 unrelated patients with sporadic and NF2-associated acoustic neuromas, meningiomas, schwannomas, and ependymomas, at eight polymorphic loci on chromosome 22. Two of the tumors studied revealed loss-of-heterozygosity patterns, which is consistent with the presence of chromosome 22 terminal deletions. By using additional polymorphic markers, the terminal deletion breakpoint found in one of the tumors, an acoustic neuroma from an NF2 patient, was mapped within the previously defined NF2 region. The breakpoint occurred between the haplotyped markers D22S41/D22S46 and D22S56. This finding redefines the proximal flanking marker and localizes the NF2 gene between markers D22S41/D22S46 and D22S28. In addition, we identified a sporadic acoustic neuroma that reveals a loss-of-heterozygosity pattern consistent with mitotic recombination or deletion and reduplication, which are mechanisms not previously seen in studies of these tumors. This finding, while inconsistent with models of tumorigenesis that invoke single deletions and their gene-dosage effects, lends further support to the recessive tumor-suppressor model.

Blotting, Southern↗
PubMed1992

Selection of surgical approach to acoustic neuroma.

A variety of surgical approaches are available in the management of acoustic neuroma. Each procedure has certain advantages and disadvantages in terms of surgical exposure, the capability of preserving cranial nerve function, and postoperative morbidity. This article advocates tailoring the operative approach to each acoustic neuroma according to its size, location, and clinical manifestations.

Age Factors↗
PubMed1991

Surface coil spectroscopic imaging: time and spatial evolution of lactate production following fluid percussion brain injury.

Detailed temporal and spatial distributions of lactate production are presented for graded fluid-percussion brain injury in the rat. A one-dimensional proton spin-echo spectroscopic imaging (1D SESI) technique, performed with a surface coil, is presented and evaluated. This technique, which represents a practical compromise, provides spatially localized proton nuclear magnetic resonance (NMR) brain spectra from a series of small voxels (less than 0.15 cm3) in less than 10 min, thus enabling both spatial and temporal monitoring of lactate production. These high-resolution lactate maps are correlated with hyperintense regions observed in T2-weighted images taken 10 h after impact, which, in turn, correlate with histology. The data demonstrate that, following severe trauma there is delayed production and propagation of lactate to regions of the brain that are remote from the trauma site. The extent of lactate production depends on the severity of impact. More significantly, the data show that following severe trauma, local lactate concentrations exceed 15 mumol/g, the concentration that has been claimed as the threshold for brain injury. Therefore high lactate levels cannot be ruled out a priori as a possible factor in brain injury following severe head trauma.

Animals↗
PubMed1991

Functional recovery after traumatic transtentorial herniation.

To elucidate the factors associated with functional recovery after traumatic transtentorial herniation, we reviewed the records of 153 consecutive patients admitted with clinical signs of transtentorial herniation (altered level of consciousness, anisocoria or pupillary unresponsiveness, and abnormal motor findings). Overall, 28 patients (18%) had a functional outcome: 14 patients (9%) made a good recovery and 14 were moderately disabled. Sixteen patients (10.5%) were severely disabled or vegetative, and 104 (60%) died. Compared with patients who died or were left severely disabled or vegetative, patients who had a good recovery were younger (21 versus 38 years), were significantly more likely to be children (less than or equal to 17 years old) and have anisocoria and a deteriorating Glasgow Coma Score (GCS), and were significantly less likely to be flaccid or have bilaterally fixed pupils; moderately disabled patients also had a lower median age and a higher frequency of anisocoria. There was no difference in the incidence of significant intracranial hematomas between patients with a functional outcome and those with a nonfunctional outcome. Twenty-seven percent of the 95 patients with anisocoria had a good outcome or moderate disability, whereas only 3.5% of the 58 patients with bilaterally fixed and dilated pupils at admission had a functional recovery (P less than 0.05). Age, level of consciousness, and the degree of residual upper brain stem function at admission appear to be the most important determinants of functional outcome after traumatic transtentorial herniation.

Adolescent↗
PubMed1991

Evaluation of 2,3,5-triphenyltetrazolium chloride staining to delineate rat brain infarcts.

BACKGROUND AND PURPOSE: Accurate and reproducible determination of the size and location of cerebral infarcts is critical for the evaluation of experimental focal cerebral ischemia. The purpose of this study was to compare intracardiac perfusion of 2,3,5-triphenyltetrazolium chloride with immersion of brain tissue in 2,3,5-triphenyltetrazolium chloride to delineate brain infarcts in rats. METHODS: After 6, 24, or 48 hours of ischemia induced by permanent middle cerebral artery occlusion, some rats were perfused with 2,3,5-triphenyltetrazolium chloride; other rats were given an overdose of barbiturates, after which brain sections were immersed in 2,3,5-triphenyltetrazolium chloride. Coronal sections were taken 4, 6, and 8 mm from the frontal pole, and infarct areas in perfused and immersed sections were compared; subsequently, the same sections were stained with hematoxylin and eosin. RESULTS: In rats subjected to 24 or 48 hours of occlusion, areas of infarction were clearly defined with both 2,3,5-triphenyltetrazolium chloride staining techniques, and the infarct sizes correlated well with the results of hematoxylin and eosin staining (r = 0.85-0.94). CONCLUSIONS: These results demonstrate that intracardiac perfusion of 2,3,5-triphenyltetrazolium chloride is an accurate, inexpensive, and efficient staining method to detect infarcted tissue 24 and 48 hours after the onset of ischemia in rats.

Animals↗
PubMed1990

Intraoperative ultrasound imaging of the entire brain through unilateral exploratory burr holes after severe head injury: technical note.

A portable ultrasound unit with a 3.5-MHz probe allows accurate imaging of both cerebral hemispheres and partial imaging of the posterior fossa through unilateral exploratory burr holes or a craniotomy. In patients with clinical signs of transtentorial herniation after severe head injury, this unilateral technique can detect extraaxial and intraparenchymal mass lesions more accurately than is possible with bilateral exploratory burr holes.

Adult↗
PubMed1990

Acoustic neuroma.

Acoustic neuromas are benign schwannomas that arise from the vestibular portion of the eighth cranial nerve. Small tumors confined to the internal auditory canal may be removed via an extradural subtemporal approach. Tumors that involve the cerebellopontine angle require posterior fossa craniotomy utilizing either the suboccipital or translabyrinthine technique. The choice of surgical approach depends primarily on the size of the tumor, its location, and the status of hearing in the involved ear. Operative mortality is very low. The most common sources of morbidity are hearing loss and facial nerve dysfunction.

Craniotomy↗
PubMed1990

Effect on outcome of prolonged exposure of patients to nitrous oxide.

Prolonged (several days or repeated) exposure to nitrous oxide (N2O) can cause injury or death. To assess whether relatively prolonged anesthesia with N2O in normal patients might similarly cause untoward effects, we investigated whether the addition of N2O to isoflurane anesthesia caused injury to patients having surgical resection of acoustic neuroma lasting approximately 10 h. Twenty-six patients undergoing surgical resection of acoustic neuroma were randomly assigned to a regimen that included or excluded N2O (50%-60%) during isoflurane anesthesia plus intravenous adjuvants. On average, slightly less isoflurane (0.24%) was used during anesthesia with N2O. We measured standard clinical variables (blood pressure, heart rate), oxygen saturation, neurologic status, pain, and the incidence and type of morbid outcomes. Exposure to N2O did not increase the incidence of morbid outcomes (including hepatic injury, infection, or hypoxemia), prolong hospitalization, or increase common postoperative complaints such as nausea, vomiting, coughing, or headache. Patients anesthetized with either regimen were equally satisfied with their anesthetic.

Adult↗
PubMed1989

The proliferative activity of neurilemomas.

Twenty-one patients with neurilemomas (15 intracranial and 6 intraspinal) received a 1-hour intravenous infusion of 5-bromodeoxyuridine (BrdU), 200 mg/m2 before tumor removal, to label S-phase tumor cells. Excised tumor specimens were stained by the indirect immunoperoxidase method with anti-BrdU monoclonal antibodies to determine the BrdU labeling index, or percentage of S-phase cells. The BrdU labeling index ranged from 0.1% to 3.1% (mean, 0.9%). The BrdU labeling index was greater than 1.5% in four of the 21 tumors (three trigeminal and one spinal). One acoustic tumor in a patient with neurofibromatosis type 1 had a labeling index of 1.3%, which was the highest among the acoustic tumors. The BrdU labeling indices did not correlate with the patient's age, tumor size, or the duration of signs and symptoms. There was no significant difference between the BrdU labeling indices of Antoni type A and Antoni type B tissue. The low BrdU labeling index of most of the intracranial neurilemomas coincides well with the slow growth of these tumors. As the BrdU labeling index may reflect growth potential of individual tumors, it could be used to guide the follow-up patients with incompletely resected tumor.

Adult↗
PubMed1989

Surgical exploration before computed tomography scanning in children with traumatic tentorial herniation.

Seventeen consecutive children with early clinical signs of tentorial herniation after head injury underwent immediate burr-hole exploration before computed tomography scanning. In nine children (53%), a subdural hematoma was discovered and immediately evacuated. In one, a small intracerebral hemorrhage was diagnosed by intraoperative ultrasonography. Postoperative studies showed that no intraaxial or extraaxial hematoma was missed by surgical exploration. Nine children (53%) survived; eight (47%) died. The survival rate was higher among patients with a mass lesion than among those without. Seven children had a good recovery, and two were moderately disabled (mean follow-up, 15.2 months). We conclude that a significant proportion of head-injured children with clinical signs of tentorial herniation have extraaxial hematomas that can be readily identified and evacuated by immediate surgical exploration. The survival rate and extent of recovery in children appear to be better than in similarly injured adults.

Adolescent↗
PubMed1989

Use of intraoperative ultrasonography to improve the diagnostic accuracy of exploratory burr holes in patients with traumatic tentorial herniation.

Seventeen head-injured patients with signs of brain stem compression at admission underwent emergency bilateral burr-hole exploration before computerized tomographic (CT) scanning. After exploration of the epidural and subdural spaces, real-time ultrasonography was performed intraoperatively to identify intraaxial hematomas. Epidural or subdural hematomas were identified surgically in 11 patients (65%) and immediately evacuated through a craniotomy; in 2 patients, bilateral subdural hematomas were removed. Ultrasonography showed no evidence of intracerebral mass lesions in 14 (82%) of the 17 patients, demonstrated extensive contusions of the temporal lobe in 2 patients (prompting partial lobectomy in both cases), and revealed a small intraparenchymal hematoma deep within the dominant hemisphere, which was not removed, in 1 patient. The sensitivity of ultrasound images for identifying intraparenchymal lesions was evaluated postoperatively by CT or autopsy. In 15 patients (88%), the results of ultrasonography were confirmed. In 2 (12%), CT scans showed small but significant lesions at the frontal pole missed by ultrasonography; one patient had a residual subdural hematoma, and the other a small intraparenchymal hemorrhage. These results confirm that patients with clinical evidence of brain stem compression soon after head injury often have extraaxial hematomas that can be readily identified by burr-hole exploration. Although intraparenchymal hematomas are rare immediately after head injury, they can usually be identified by intraoperative ultrasonography. This simple technique can reduce the risk of missing intracranial hematomas during emergency burr-hole exploration and improve intraoperative decision making in this population of severely head-injured patients.

Adolescent↗
PubMed1989

Magnetic resonance imaging and 31P magnetic resonance spectroscopy for evaluating focal cerebral ischemia.

Recent advances in magnetic resonance (MR) imaging and MR spectroscopy (MRS) allow the noninvasive in vivo study of a variety of anatomical, physiological, and biochemical alterations that may occur in different cerebral pathologies. The authors have investigated the use of MR imaging and MRS to monitor the evolution of experimental focal cerebral ischemia in rats. Permanent focal cerebral ischemia was induced in 36 rats, and 12 normal rats were used as a control group. Changes in high-energy phosphate metabolites were followed in vivo using MRS during the 1st hour and at 3 and 6 hours after ischemic insult. Changes in vivo MR images were evaluated at 1, 3, 6, 12, and 24 hours after ischemic insult. Significant decreases (p less than 0.05) in phosphocreatine/inorganic phosphate ratios and intracellular pH values occurred immediately after the induction of ischemia. The presence of an infarcted area seen on MR images was a constant finding at 3 hours after ischemic insult, and was well defined and localized at 12 and 24 hours. The location of areas of infarction seen on MR images correlated well with areas identified histopathologically. The T1 and T2 MR relaxation times were significantly increased 3 hours after ischemic insult and remained prolonged for at least 24 hours. The results show that MR imaging is a sensitive method to measure cerebral infarction, and that MRS is a sensitive measure of changes that occur in the early phases of ischemia, perhaps when cellular changes may still be reversible. At 3 and 6 hours after the ischemic insult, however, 31P-MRS spectra may appear to be "normal" despite the presence of well-documented areas of infarction.

Animals↗
PubMed1989

Nonoperative treatment of spinal epidural infections.

Spinal epidural infections were diagnosed before the onset of neurological deficits in six patients and treated nonsurgically. The diagnosis was based on the clinical presentation and on the results of myelography and computerized tomography scanning. Positive cultures were obtained from blood in all six patients, from aspiration of a paraspinous infection in two, and from a skin abscess and a pulmonary empyema in one patient each. Staphylococcus aureus was the causative organism in five cases. All patients were treated with intravenous antibiotics and remained neurologically intact throughout the course of treatment. Five patients have had no recurrence of their symptoms. One patient eventually required surgery for persistent discitis.

Adult↗