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Biomedical subjects

D M Long

Publications and source records attributed to D M Long.

At least 19 recordsLinked to original sources

The utility of magnetic resonance imaging in the diagnosis of intranasal meningoencephaloceles.

We present three patients in whom the diagnosis of intranasal meningoencephalocele was made by magnetic resonance imaging. The initial clinical evaluation and computed tomographic examinations of these patients failed to distinguish between chronic inflammation and intranasal meningoencephalocele. Although both computed tomography and magnetic resonance imaging are used to distinguish between normal, inflammatory, and neoplastic tissue in the nasal cavity and paranasal sinuses, limitations do exist and these are the focus of our communication. A clear understanding of the efficacy of these radiographic modalities will enhance surgical planning and can preclude severe complications.

Encephalocele

Effect of emulsion concentration on biodistribution of perflubron in tumor-bearing mice.

Perflubron (perfluoroocytlbromide, PFOB) emulsion concentrations of 100%, 90%, or 60% w/v were administered to mice with and without 3 types of murine malignant tumor implants, and the distribution in blood, tumor, lung, liver and spleen were studied 48 hours after a dose of 10 or 3 g/Kg of PFOB. The most important changes were seen in the blood where the PFOB concentration [PFOB] was decreased in tumor bearing mice (TBM). Blood [PFOB] was also decreased in TBM and normal mice (NM) that received the 60% emulsion. Liver [PFOB] was increased in TBM. Lung [PFOB] was directly proportional to the emulsion concentration with the 10g/Kg dose. No major differences were seen in the biodistribution between the 100% and 90% emulsions using 10g/Kg, in spite of differences in composition and manufacturing history.

Animals

Cyclooxygenase inhibition with ibuprofen: effect on biodistribution of perflubron emulsions in mice with mammary tumor.

The biodistribution of Perflubron (perfluorocytylbromide, PFOB) was studied by infusing 10 or 3 g/Kg doses of 90% and 100% w/v emulsions into Balb C mice with and without malignant mammary tumor implants. PFOB concentrations were measured in blood, liver, spleen, lung and tumor, and X-rays were taken 48 hours after infusion. Ibuprofen (IBU) was given intraperitoneally 10 mg/Kg dialy for 3 days to study the effects of cyclooxygenase blockade. The results showed that the blood [PFOB] in tumor-bearing mice (TBM) was only 3.6% of that measured in normal mice (NM), and the liver [PFOB] was increased by 59%. The lung [PFOB] increase with IBU therapy in NM was highly significant. IBU therapy resulted in a 98% and 468% increase in blood [PFOB] in normal and TBM, respectively. Smaller but statistically significant changes occurred in blood [PFOB] with saline and sham injections. Tumor [PFOB] was lower by 17% (P = .028) in mice treated with IBU. Smaller decreases were seen with saline and sham injections but did not achieve statistical significance. In conclusion, the presence of this malignant tumor resulted in changes that might influence the usefulness of PFOB as a contrast agent and as an adjuvant for radiation and chemotherapy. This study shows that cyclooxygenase inhibition significantly modified the pharmacodynamics of PFOB emulsions in blood, tumor and lung. The changes seen in the saline placebo and sham category were attributed to stress from procedures.

Animals

Decision making in lumbar disc disease.

When a patient presents with an acute pain syndrome suggestive of a herniated lumbar disc, nonoperative treatment is almost always the rule. Urgent surgery is undertaken for intractable pain, significant or progressive neurological deficit, and abnormalities of bowel, bladder, or sexual function. Evaluation of the patient is not needed in typical cases until nonoperative care has failed. The decision to evaluate and treat by intervention is made after a reasonable time, usually a minimum of 1 month and a maximum of 3 for the patient who is not making progress. Slow recoveries can be monitored for even longer if agreeable with the patient. The decision for intervention is almost never warranted in the face of normal imaging studies. Several interventions are possible. Traditional surgery, with or without magnification, is followed by an excellent outcome. Chymopapain injection is a reasonable alternative for those expert in its use. Percutaneous discectomy is a possibility but remains to be proved by acceptable clinical studies. Lumbar disc surgery is highly successful and complications are extremely unusual. They do occur however, and can be extremely serious. Unexpected postoperative complications should be investigated immediately. Recovery from disc surgery usually is uneventful, and no rehabilitation is required. Some patients, particularly those who do heavy work, can be helped by a rehabilitation program that stresses return to normal function. Rarely will a patient develop a serious neurological deficit following surgery. Unexpected serious deficits require urgent reevaluation. Most patients return to work promptly without assistance. For those who cannot, referral to a multidisciplinary rehabilitation program to assist with return to function through general management of comorbidities can be useful. It is a rare patient who is disabled by a back disorder, and the decision that a patient is disabled should be made only after thorough evaluation and adequate rehabilitative therapy.

Disability Evaluation

Non-glial tumors of the brain: tumors of the cerebellopontine angle and meningiomas.

The principal non-glial tumors of the brain are meningiomas and acoustic schwannomas. Advances in the management of meningiomas have included endovascular techniques for embolization to reduce blood loss, radical surgical approaches, and the recognition of the high recurrence rate of these tumors. Advances in the management of acoustic tumors have been in preservation of VIIth nerve function, improved preservation of hearing, and the availability of stereotactic radiosurgical techniques as an alternative. There is still a substantial discussion concerning the route of surgery for acoustic tumors and not all agree that hearing preservation is a reasonable goal at present.

Cerebellopontine Angle

Strategic planning has market orientation.

A key element in the strategic planning process is active involvement of the hospital's key personnel so that each has a commitment to the ultimate plan.

Administrative Personnel

Dibutyryl cyclic adenosine 3',5'-monophosphate: its role in regulation of cat brain extracellular fluid.

The role of dibutyryl cyclic adenosine 3',5'-monophosphate (db cAMP) in influencing the water content of the cat's gray and white matter was evaluated by intracoritcal injection of 20 micrio L of 2 x 10(-1) to 2 x 10(-6)M solution of db cAMP. Cholera toxin, a stimulator of adenylate cyclase, also was tested. Concentrations of db cAMP less than 10(-3)M failed to produce significant change in brain water content, while concentrations greater than 10(-2)M produced 31.5% +/- 8% and 17.3% +/- 3.6% increases in white matter volume, respectively (P less than .05). Cholera toxin did not increase brain water levels. These results are discussed in relation to the pathophysiology of brain edema.

Animals

Comparison of radiopaque perfluorocarbon and Ethiodol in lymphography.

Lymphangiography was performed on 40 adult cats, 39 dogs, 20 rabbits, and 12 rats of mixed sex using Ethiodol or radiopaque perfluorocarbon (BPC). Ethiodol was more radiodense than RPC, but imaging of lymph channels and nodes was satisfactory with the latter. RPC could be infused rapidly, while Ethiodol infusion was time consuming. RPC was biologically inert; Ethiodol produced both local and systemic inflammatory reactions. The lymph node distribution with RPC was more uniform and persisted for longer periods. It was concluded that RPC was an improvement over Ethiodol for lymphangiography.

Animals

Surgical postoperative bleeding associated with aspirin ingestion. Report of two cases.

Two patients are reported in whom repeated postoperative hematomas appeared to be secondary to aspirin-induced platelet defect. Routine bleeding and clotting studies will not demonstrate this platelet-induced coagulopathy. A previous history of massive aspirin ingestion makes such a coagulopathy a serious consideration, but the platelet defect may occur with small doses of aspirin. Such aspirin ingestion should be viewed with great concern by the neurosurgeon. The defect is treatable by platelet transfusion.

Aged

Capillary ultrastructure in human metastatic brain tumors.

The ultrastructural characteristics of blood vessels within 18 metastatic neoplasms of the brain have been studied. The abnormal permeability to protein-bound tracers was found to be related to defective capillary endothelium. Abnormalities include gap functions, fenestrations of membranes, and open normal junctions. The abnormal capillaries had the character of capillaries from current tissue. Endothelium cell abnormalities were not found in surrounding edematous brain.

Blood-Brain Barrier

The anatomy of the so-called "articular nerves" and their relationship to facet denervation in the treatment of low-back pain.

Disections of the dorsal rami of L1--5 were performed in human cadavers, and the course of the dorsal rami, their branches, and the innervation of the zygapophyseal joints in the lumbar region were specifically studied. At the L-1 through L-4 levels, the dorsal rami divide into medial and lateral branches within the intertransverse ligaments. Each medial branch runs across the root of the adjacent superior articular process. At the caudal edge of the process, the branch turns medially beneath the mammillo-accessory ligament. Beneath the mammillo-accessory ligament, medial branches occur that innervate the adjacent zygapophyseal joint, and distal zygapophyseal branches arise at the laminar level to innervate the next lower joint. The L-5 dorsal ramus runs along a groove between the ala of the sacrum and its superior articular process. A the caudal edge of the articular process, the ramus divides into medial and lateral branches, and the medial branch supplies the L5--S1 articulation.

Back Pain

Dynamics of cerebral edema. The role of an intact vascular bed in the production and propagation of vasogenic brain edema.

Brain edema was produced in cats by a standardized cortical freezing lesion. With a careful microsurgical tehnique, the injured cortex was removed as a single piece, either immediately after induction or at 2, 4, or 8 hours after lesion production. The injured brain was either discarded or replaced in its bed. Brain edema and the defect in the blood-brain barrier were assessed by determining percent dry weight, increase in volume of white matter, and spread of Evans' blue by planimetry. The results indicate that 1) if the lesion is removed immediately after production, formation of the expected vasogenic brain edema is completely abolished; 2) replacement of the frozen brain is unable to induce significant increase in permeability of the surrounding blood-brain barrier or a significant amount of brain edema; and 3) if the lesion is removed at 2, 4, or 8 hours with or without replacement, advancement of the edema front and increase in the amount of edema is stopped. It appears that an intact vascular bed is necessary for the extracellular fluid component of brain edema, and that no edemagenic factors exist within the injured brain in this model that influence either the production or propagation of the increased extracellular fluid volume.

Animals

Thalamic EEG recordings in patients with chronic pain.

Thalamic EEG recordings were made in 10 patients; the therapeutic goal of the implantation was the electrical stimulation treatment for pain. The patients' ages ranged from 37 to 72 years; seven patients had thalamic pain (Dejerine-Roussy syndrome), two had chronic spinal arachnoiditis and one had facial anaesthesia dolorosa. Platinum-iridium electrodes were stereotaxically inserted; the ventrobasal complex of the thalamus including the ventral posterior zone was the target of the implant. Excessive thalamic slowing was found in four of seven patients with Dejerine-Roussy syndrome and also in two of three cases with other causes of pain. One patient had marked rhythmical intermittent delta activity in the thalamus which was often triggered by arousing stimuli. Thalamic spindle activity was sometimes noted without concomitant spindle activity on the scalp and would occasionally occur in states of early drowsiness.

Adult

Tumor imaging with x-rays using macrophage uptake of radiopaque fluorocarbon emulsions.

Radiopaque fluorocarbon (RFC) emulsions were prepared with small particle size and high concentration of the fluorocarbon. When RFC emulsions were injected intravenously in hamsters, rats, and mice with eight types of malignant tumors, the tumors became radiopaque, except in the mice with spontaneous teratoma of the ovaries. Tumors as small as 3 to 4 mm could be defined radiographically using routine x-ray techniques. The tumors remained radiopaque for days to weeks after injection. Light and electron microscopy revealed characteristic fluorocarbon vacuoles primarily in the tumor macrophages. Thus RFC emulsions may be useful in detection of malignant tumors.

Animals