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Biomedical subjects

J M Lohr

Publications and source records attributed to J M Lohr.

9 recordsLinked to original sources

A methodological critique of the current status of eye movement desensitization (EMD).

Eye Movement Desensitization (EMD) has been recently advocated as a rapid treatment for the elimination of traumatic memories responsible for the maintenance of a number of anxiety disorders and their clinical correlates. Despite a limited conceptual framework, EMD has attracted considerable interest among clinicians and researchers. The popularity and interest generated by EMD will likely result in wide usage. We present a methodological critique of it with reference to assessment, treatment outcome, and treatment process. We also provide guidelines for judging the methodological adequacy of research on EMD and suggest intensive research to assess effectiveness, treatment components, and comparisons with other procedures.

Anxiety Disorders

Operative management of greater saphenous thrombophlebitis involving the saphenofemoral junction.

Forty-three consecutive patients with greater saphenous vein (GSV) thrombosis extending to the saphenofemoral junction (SFJ) were treated. Twenty-three patients had extension of thrombus into the common femoral vein (CFV). Twenty patients had thrombus extending to but not within the CFV. Symptoms, risk factors, and physical examination were not predictive of CFV thrombus extension. When compared with the operative record, duplex scans accurately located the extent of the thrombosis 100% of the time. Forty-one surgical procedures were performed. No patients had pulmonary emboli during the procedures. Thirty-seven patients were treated as outpatients or were discharged within 3 days of their surgical procedures. The two patients who did not undergo operative procedures in this series had complete occlusion of the CFV with extension into the external iliac vein. Thrombus within 3 cm of the SFJ is an indication for surgical intervention. Disconnection of the GSV from the CFV prevents extension of the thrombus, and a limited CFV thrombectomy can be performed when necessary. This is considerably more cost-effective than treatment with anticoagulation.

Adult

Global cerebral ischemia associated with cardiac arrest in the rat: I. Dynamics of early neuronal changes.

Light microscopic neuronal changes were studied in rats subjected to 10 min of global ischemia produced by compression of the major cardiac vessels. Observations of cresyl violet-stained sections revealed early changes involving predominantly GABAergic neurons in various locations. In rats killed 15 min after recirculation, the changes were characterized by the appearance of a clear peripheral zone with condensation of the remaining neuronal cytoplasm. After 1 h, these zones appeared to be compartmentalized into individual pearl-like vacuoles, especially prominent in the nucleus reticularis thalami. After 3 h, the cytoplasmic vacuoles disappeared and the neuronal changes, particularly in the cerebral cortex, striatum, hippocampus, and pars reticulata of the substantia nigra, consisted mainly of hyperchromasia or loss of Nissl substance. After 2 days, the cerebral cortex and thalamus contained occasional neurons with conspicuously large nucleoli. After 7 days, the hippocampus revealed an approximately 50% loss of CA1 pyramidal neurons, associated with intense microglial reactivity in the stratum radiatum, whereas the neuronal destruction was more complete in the nucleus reticularis thalami. Our observations suggest a possibility that early changes in GABAergic neurons may provide a period of neuronal disinhibition and thus contribute to an excitatory ischemic damage in regions connected by GABAergic circuitry.

Animals

Upper extremity venous duplex imaging.

Over 500 upper extremities have been imaged with the Duplex Scanner at the John J. Cranley Vascular laboratory. Venous anatomy and imaging techniques are presented. Reference points and zones for localizing abnormal findings are demonstrated. Abnormal venous pathology including case presentations of acute radial, basilic, cephalic, and axillary vein thrombosis are presented. Complications of subclavian and internal jugular vein catheterization are demonstrated. Soft tissue pathology including edema, lymphadenopathy, hematomas, cysts, and abscesses are visualized and differentiated. Duplex use for evaluation of aneurysm, pseudo aneurysm and graft surveillance has been increasing in frequency. Examples are demonstrated.

Arm

Lower extremity calf thrombosis: to treat or not to treat?

Seventy-five patients with isolated calf vein thrombi were prospectively monitored with sequential duplex scans at 3- to 4-day intervals. Twenty-four patients (32%) propagated and 11 of these 24 (46%) into the popliteal or larger veins of the thigh. Sex, age, obesity, trauma, estrogen use, malignancy, varicose veins, smoking, surgery, and activity level were not predictive for proximal propagation. Proximal soleal vein thrombi had the highest incidence in both propagating and non-propagating groups. Thrombus extent and bilateral involvement were not predictive of propagation. Five percent (4 of 75 patients) had highly probable ventilation perfusion scans as their initial indication for duplex scanning. Deep vein thrombosis isolated to the calf is not a benign problem. If anticoagulant therapy is contraindicated, the progress of the thrombus can be followed by duplex scanning.

Adult

Superficial thrombophlebitis diagnosed by duplex scanning.

Since July 1982, this noninvasive vascular laboratory has performed 12,856 lower extermity venous duplex examinations. All cases of acute venous thrombosis have been categorized and entered into a computer data base. One thousand four hundred twelve examinations were positive for acute venous thrombosis. This report analyzes the laboratory's entire experience with superficial thrombophlebitis (SVT). One hundred eighty-six patients were diagnosed by duplex scanning to have SVT. Women outnumbered men 99 to 87. They were slightly older (average age 58.4 +/- 16.2 years) compared with the men (53.8 +/- 14.2 years). Men were more likely to have a complicated course of SVT (40% vs 22%; p less than 0.01). Complications included either radiographically documented pulmonary embolism or deep venous involvement. Fifty-seven (31%) patients had at least one complication of SVT. A series of predisposing factors was analyzed and six factors were associated with an increased risk of complications. They are bilateral SVT (p less than 0.01), age greater than 60 years (p less than 0.01), male sex (p less than 0.01), history of deep venous thrombosis (p less than 0.01), bed rest (p less than 0.02), and presence of infection (p less than 0.02). Location of thrombus within the greater saphenous vein (35%) was most likely to be associated with complications. Isolated varicosities (8%) were least likely to be associated with complications. Duplex scanning identifies a significant number of complications of patients with SVT and should be obtained in cases of saphenous vein involvement or in the presence of associated risk factors.

Aged

Putative neuroexcitation in cerebral ischemia and brain injury.

Involvement of neuroexcitatory mechanisms in cerebral ischemia and brain injury was explored in experimental models of repetitive forebrain ischemia by temporary occlusion of carotid arteries in gerbils and cryogenic injury to the cerebral cortex in rats and gerbils. Our observations in these models revealed a pattern of injury that involved some anatomic structures outside the areas of direct ischemic or traumatic insult. Such foci of injury revealed conspicuously abnormal uptake of 45Ca associated with slight or moderate neuronal alteration, whereas severely injured areas showed no 45Ca uptake. Electron microscopic observations revealed a characteristic presence of calcium in swollen dendrites, closely resembling pictures obtained in neuroexcitatory conditions such as epileptic seizures. Abnormal uptake of 45Ca was associated with apparent blood-brain barrier changes characterized by intracytoplasmic uptake of extravasated albumin into the neurons. Protein synthesis assayed by in vivo [3H]leucine incorporation was reduced in regions showing calcium accumulation. Our observations suggest that neuroexcitation may play an important role in development of secondary and chronic changes after ischemic or traumatic brain insults.

Animals

Experimental model for repetitive ischemic attacks in the gerbil: the cumulative effect of repeated ischemic insults.

An experimental model for repeated ischemic attacks, which allows easy induction of cerebral ischemia of any desired duration and frequency, has been developed in the gerbil. With this procedure, a pronounced cumulative effect on development of edema and tissue injury was observed using 3 separate, 5-min bilateral occlusions of the common carotid arteries spaced at various time intervals. This effect was most evident when the occlusions were carried out at 1-h intervals, i.e., during the period of marked postischemic hypoperfusion. Such animals, killed after 24 h of recirculation, showed significantly more severe edema and brain tissue injury in the areas exposed to ischemia than was observed in animals killed 24 h after single 5- or 15-min occlusions. The changes of regional CBF, assayed with a [3H]nicotine method, indicated a relatively rapid onset of hypoperfusion of similar degree after each release of arterial occlusion. The hypoperfusion recovered significantly within 6 h of recirculation following either single or multiple occlusions, and no residual hypoperfusion was observed in animals which, when killed at 24 h, showed severe edema and brain tissue injury. This model should prove useful in elucidating the pathophysiological mechanisms operative in repetitive cerebral ischemia.

Animals

Experience with physiologic amputation using the CryoCare Extremity Stabilization System (CESS).

Five years of experience gained with the CryoCare Extremity Stabilization System (CESS) were evaluated in this study. Twenty-one patients underwent freezing amputation. Five patients died before undergoing surgical amputation. Symptomatic relief, control of odor, decreased demand on nursing staff, and appreciation of the family make this approach valuable even when long-term survival is not anticipated. Ten patients who underwent freezing amputation subsequently underwent surgical amputation and were discharged. Six patients underwent freezing and surgical amputation but died prior to discharge. The patients selected for the freezer application were deemed to be prohibitive operative risks because they were experiencing systemic toxicity from their ischemic limb and underlying diseases. Six patients demonstrated myoglobinuria prior to freezing which cleared with CESS. The physiologic amputation allowed stabilization of medical problems including cardiac arrhythmias, congestive heart failure, sepsis, renal failure, diabetes, and respiratory failure. Freezing of an ischemic extremity allows delay in amputation enabling physicians to achieve maximal medical stabilization. It permits symptomatic relief in patients whose long-term survival is not anticipated. Physiologic freezing amputation should be included in the repertoire of all surgeons.

Adult