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Biomedical subjects

D M Long

Publications and source records attributed to D M Long.

At least 163 records · Page 9Linked to original sources
PubMed1979

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↗
PubMed1979

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↗
PubMed1979

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↗
PubMed1978

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↗
PubMed1978

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↗
PubMed1978

Colloquium--is there a surgical cure for pain?

We have heard today that psychological factors are extremely important in pain problems and that careful psychiatric assessment should delineate patients who have the potential of achieving good pain relief with interventional procedures. The bulwarks of the neurosurgical management of pain have been peripheral neurectomy, rhizotomy, sympathectomy, and cordotomy. We have heard each of these discussed. Peripheral neurectomy and rhizotomies are not highly successful in the treatment of pain, but are useful in carefully chosen patients. Cordotomy remains an excellent technique for the management of many patients with chronic pain or malignancy, and sympathectomy can be one of the most gratifying operations performed, as long as the patients are well chosen. The major lesson we have learned today is that there is no cure for pain at the present time. Nevertheless, neurosurgical procedures remain an important part of pain management. They should be applied after an adequate diagnosis is made, after psychiatric characterization of the entire pain problem is complete, and only when there is only a definitive pain generator which can be relieved by an interventional procedure. Perhaps the most important message we have heard is the categorization of pain patients given us by Doctor Hendler. It is important that we all identify those patients with affective or exaggerated pain behavior so that interventional procedures are carried out only on those patients who have a real possibility of benefiting from them. I believe if we all do this, we will see a significant increase in the effectiveness of surgical procedures for pain.

Cordotomy↗
PubMed1978

Electrical stimulation of the nervous system for pain control.

Transcutaneous electrical stimulation appears to be a valid technique for the treatment of many pain states. Its use in chronic pain is limited and it appears to be much more likely to be effective in the relief of acute painful states. Nevertheless, since it provides a simple way to treat a significant number of patients whose pain would otherwise by intractable, it has been a valuable addition to the armamentarium of the physician dealing with chronic pain. Peripheral nerve stimulation is an excellent way to relieve pain of peripheral nerve injury origin and certain painful, poorly understood, vasopastic or reflex sympathetic states. Spinal cord stimulation has been revived by the advent of percutaneous stimulators. The technique is currently the best available for the treatment of the patient suffering from the chronic low back syndrome with severe arachnoiditis, for whom no definitive therapy is available. Brain stimulation has been relegated to therapy for pain of central nervous system origin. It is a most promising technique though its application appears to be limited at this point to a few specific problems. The seriousness of potential complications has kept it from being widely applicable to date. There is little information concerning the mechanism whereby these various techniques are effective. Transcutaneous and peripheral nerve stimulation might have their effect through peripheral mechanisms or through a gating mechanism in the posterior horn (Melzack and Wall 1965; Campbell and Taub 1973). Spinal cord stimulation could act through a retrograde effect upon a dorsal horn gate or have more central actions. Brain stimulation in the opiate receptor system may be effective through activation of this system. The mechanisms of action of stimulation in the sensory system centrally are certainly not well understood (Bloedel 1974).

Brain↗
PubMed1978

Enlarging optic chiasmal glioma with stable visual acuity.

A 13 1/2-year-old girl with stable, reduced visual acuity, nystagmus and Small, pale optic discs initially noted at age nine months, developed signs and symptoms of increased intracranial pressure. At craniotomy, an intrinsic glioma of the optic chiasm and both optic nerves extended into both frontal lobes, the hypothalamus and the third ventricle.

Adolescent↗
PubMed1977

Uses of percutaneous electrical stimulation of the nervous system.

Temporary percutaneous electrical stimulation of peripheral nerves and the spinal cord is a valuable screening technique. This approach will provide a much higher success rate for identifying those patients suitable for a permanently implanted stimulation system. The system appears to be the treatment of choice for chronic, intractable pain caused by nerve injury. The author presents his surgical procedures for stimulation of peripheral nerve and spinal cord. A summary of clinical results is discussed.

Electric Stimulation↗
PubMed1977

Electrical stimulation for the control of pain.

Electrical stimulation for the control of pain is now a well accepted therapeutic modality. Transcutaneous application of electrical stimulation is the most common technique employed and has been used to treat chronic pain, acute surgical pain, and acute pain of other origins. Percutaneous application of electricity to the nervous system through needles electrodes is useful in predicting the efficacy of implantable stimulators and has served the same function as diagnostic nerve block. Implantable stimulators have been used for stimulation of peripheral nerves, the anterior and posterior surfaces of the spinal cord, and the brain. Peripheral nerve stimulators are the most efficacious of the implantable devices. They are used specifically for pain of peripheral nerve injury origin. Their use for pain outside the distribution of the nerve stimulated is not yet proved.

Brain↗
PubMed1977

Perfluoroctylbromide as a diagnostic contrast medium in gastroenterography.

The efficacy and safety of perfluoroctylbromide as a diagnostic contrast medium for gastroenterography was studied in laboratory animals. It was found that perfluoroctylbromide possesses excellent coating properties and a short transit time in the gastrointestinal tract. The conscious animals tolerated 64 ml/kg without any toxic manifestations. Thorough hematologic, serologic and histologic examinations showed no evidence of any adverse effects. Perfluoroctylbromide may be especially useful in patients with advanced inflammatory lesions of the gastrointestinal tract or in those with risk of aspiration of contrast medium into the lungs during gastroenterographic examinations.

Alanine Transaminase↗
PubMed1977

Transnasal transsphenoidal approach to the sella.

The transnasal transsphenoidal approach to the sella turcica has been refined and perfected through advances in medicine and technology. Originally performed for excision of pituitary adenomas, its present primary use is pituitary ablation is hormonally dependent diseases. Our study of 55 patients who have undergone this procedure during the years 1970-1975 demonstrates that this microscopic technique gives excellent exposure and visualization of intrasellar contents. Our method gives excellent exposure and visualization of intrasellar contents. Our method with several instrument modifications is discussed. It is technically an easy procedure with a minimum of morbidigy and mortality.

Adenoma↗
PubMed1977

Use of microfibrillar collagen as a topical hemostatic agent in brain tissue.

Microfibrillar collagen, a recently introduced topical hemostatic agent, was used to obtain hemostasis in suction-evacuation lesions of canine cortex. Gelatin foam was used as a control in identical lesions on the opposite side. Microfibrillar collagen was found to be faster acting and more effective than gelatin foam. Histological evaluation of the lesions at 2,4, and 6 months postoperatively showed no significant difference in the amount or type of tissue reaction to the two agents.

Animals↗