Showing papers by "Mayo Clinic published in 1983"

Articular and ligamentous contributions to the stability of the elbow joint

Abstract: This preliminary study of four elbow specimens investigates the relationship of articular geometry and ligamentous structures in providing stability to the elbow joint. A technique is presented that describes the constraining features of varus-valgus and distraction in extension and at 90 degree of elbow flexion. Valgus stability is equally divided among the medial collateral ligament, anterior capsule, and bony articulation in full extension; whereas, at 90 degrees of flexion the contribution of the anterior capsule is assumed by the medial collateral ligament which provides approximately 55% of the stabilizing contribution to valgus stress. Varus stress is noted to be resisted primarily by the anterior capsule (32%) and the joint articulation (55%) with only a small (14%) contribution from the radial collateral ligament. At 90 degrees of flexion, little change is noted in the contribution to the radial collateral ligament (9%), but the anterior capsule offers only 13%, with the remaining stability (75%) arising from the joint articulation. In extension, the soft tissue resistance to distraction is provided minimally by either the radial (5%) or the medial (5%) collateral ligaments, and thus primarily originates from the anterior capsule (85%). At 90 degrees of flexion, however, the capsule offers virtually no resistance to distraction (8%). The radial collateral ligament contributes 10% of the stability, while the medial collateral ligament accounts for 78% of the resistance to distraction in this position. Too few specimens have been studied to form any conclusions for direct clinical applications at this time. However, the technique provides a reliable tool with additional studies for different positions and loading conditions underway. These efforts should disclose useful information that might be applied to the management of chronic elbow instability, radial head or olecranon fracture, the design and implantation of elbow prostheses, or provide a rationale for other reconstructive procedures.

Apolipoprotein A-I as a Marker of Angiographically Assessed Coronary-Artery Disease

Abstract: This study was designed to determine whether the plasma level of apolipoprotein A-I is a better discriminator of angiographically documented coronary-artery disease than the level of high-density–lipoprotein (HDL) cholesterol in male subjects. The level of plasma apolipoprotein A-I in 83 patients with coronary-artery disease was 96.7±4.2 mg per deciliter (mean ±S.E.M.), which was significantly lower (P<0.0001) than the level in 25 patients without coronary-artery disease (146.9±2.1 mg per deciliter). The levels of HDL cholesterol were also lower (P<0.0001) in patients with coronary-artery disease (31.9±1.5 mg per deciliter) than in those without it (45.9±2.3 mg per deciliter). A stepwise discriminant analysis, however, indicated the superiority of apolipoprotein A-I over HDL cholesterol in detecting coronary-artery disease. Furthermore, a linear discriminant analysis suggested that although HDL cholesterol by itself was a discriminator of coronary-artery disease, it did not provide a substantial ...

Quantitative sudomotor axon reflex test in normal and neuropathic subjects

Abstract: We have quantified postganglionic sweat output in human subjects resulting from axon reflex stimulation using acetylcholine electrophoresis. Dehumidified nitrogen of controlled temperature and flow rate was passed through an acrylic plastic chamber placed over a defined area of skin. Sweat droplets were evaporated; humidity change was sensed by a narrow-range humidity sensor housed in a temperature-controlled compartment and was plotted on a chart recorder. The time integral (area under the curve) was continuously integrated and converted to absolute units using a derived equation. Because stimulation and recording were simultaneous, an accurate determination of the latency of the sweat response was also possible. Quantitative sudomotor axon reflex tests were performed on the left forearm and foot of 33 female and 29 male normal subjects aged 11 to 69 years. Acetylcholine, 10%, was electrophoresed for 5 mA-minutes in the forearm and 10 mA-minutes in the foot, and recording was continued for an additional 5 minutes. The mean sweat output in males was 2.7 and 3.0 times that in females in forearm and foot, respectively (p < 0.0001). Studies in selected autonomic neuropathies confirm that quantitative sudomotor axon reflex tests will detect postganglionic sudomotor abnormalities sensitively and reproducibly.

Inhibitory Role of the Endothelium in the Response of Isolated Coronary Arteries to Platelets

Abstract: Aggregating autologous platelets caused contraction of isolated rings of canine left circumflex arteries. The contractions were augmented after removal of the endothelium and were attenuated by serotonergic antagonists. During contraction caused by prostaglandin F2 alpha, aggregating platelets caused a transient increase in tension followed by a profound relaxation of arteries with endothelium, but caused only further contraction of arteries without endothelium. These observations demonstrate the importance of the vascular endothelium in opposing the constriction of coronary vessels caused by 5-hydroxytryptamine and other substances released from aggregating platelets.

Nimodipine Improves Cerebral Blood Flow and Neurologic Recovery after Complete Cerebral Ischemia in the Dog

Abstract: Ten minutes of complete ischemia was produced in 11 dogs by temporary ligation of the aorta. Immediately before the ischemic episode, the dogs received nimodipine, a new calcium entry blocker, 10 μ...

Complications of Cerebral Angiography: Prospective Assessment of Risk

Abstract: A prospective study of 1,517 consecutive cerebral angiographic examinations is reported. The incidence of all complications was 8.5%, and the incidence of all neurologic complications was 2.6%. The overall incidence of permanent neurologic deficit was 0.33%.. The incidence of permanent neurologic deficit in patients referred for evaluation of symptomatic cerebrovascular disease was 0.63%. Older age, increased serum creatinine concentration, and the use of more than one catheter all were significantly associated with serious neurologic complications. Although patients with a recent stroke or frequent transient ischemic attacks had a higher incidence of serious neurologic complications, this increase was not statistically significant for this sample.

The incidence of bulimia in freshman college students

Abstract: This paper reports the results of a questionnaire survey administered to 1355 college freshman (98.3% response rate) and to a comparison group of 37 female bulimic patients. Questions were contructed to elicit information which would allow identification of those respondents who would meet DSM-III requirements for diagnosis of bulimia. 2.1% of the student population (4.5% of females, 0.4% of males) met these modified criteria and the additional criterion of weekly binge-eating. The identified “bulimic” female students differed from female bulimic patients in their use of fasting instead of self-induced vomiting for weight control, and in their tendency to be overweight. “Bulimic” female students are also compared with nonbulimic students.

Primary sclerosing cholangitis: findings on cholangiography and pancreatography

Abstract: Cholangiograms of 86 patients with primary sclerosing cholangitis (PSC) were compared with those of 82 patients with primary bile duct carcinoma and 16 with primary biliary cirrhosis. Multifocal strictures involving both intra- and extra-hepatic bile ducts were most common in PSC; they were diffusely distributed, short, and annular, alternating with normal or slightly dilated segments to produce a "beaded" appearance. Very short, band-like strictures occurred in 18 patients; 9 also had diverticulum-like out-pouchings. Fourteen patients had "diverticula" without band strictures. Both findings appear to be specific for PSC. Inflammatory bowel disease was seen in 57 patients (66%), who could not be distinguished cholangiographically from other PSC patients. Of 40 patients with adequate retrograde pancreatograms, 3 had abnormalities of the pancreatic ducts.

Osteosarcoma of the jaw.

Abstract: The records of 66 patients with osteosarcoma of the jaw were reviewed. The ages of the 42 males and 24 females ranged from 12 to 79 years (mean, 34.2 years). Swelling and pain, the most frequent presenting complaints, were noted an average of three months before the patient was seen by a physician. Fifty-one percent of the lesions involved the maxilla and 49% involved the mandible. The most common sites of involvement were the body of the mandible and the alveolar ridge of the maxilla. Radiologically, most of the lesions in the maxilla were osteoblastic (50%), whereas most of those in the mandible were osteolytic (43%). Chondroblastic osteosarcoma was the most frequent histologic type (48%) and was associated with the best survival rate (47%). Treatment included radical and local surgery with radiotherapy, chemotherapy, or various combinations. The recurrence rate for all treatment modalities was 70%. Patients treated by initial radical surgery had the best survival (80%). Survival decreased to 27% with local surgery. Of the 43 (65%) patients who died, most died with uncontrolled local disease; only four patients had documented distant metastasis, which involved lung, cervical lymph nodes, spinal column, and brain.

Trial of combined warfarin plus dipyridamole or aspirin therapy in prosthetic heart valve replacement: Danger of aspirin compared with dipyridamole

Abstract: Despite the use of oral anticoagulation in patients with prosthetic heart valves, persistent thromboembolism over time warrants a search for improved methods of prevention. Thus, patients receiving 1 or more mechanical prosthetic heart valves were randomized to therapy with warfarin plus dipyridamole (400 mg/day) or warfarin plus aspirin (500 mg/day) on the basis of location and type of valve and surgeon, and followed up with a concurrent, nonrandomized control group taking warfarin alone. In 534 patients followed up 1,319 patient-years, excessive bleeding (necessitating blood transfusion or hospitalization) was noted in the warfarin plus aspirin group (23 of 170 [14%], or 6.0/100 patient-years) compared with warfarin plus dipyridamole (7 of 181 [4%], or 1.6/100 patient-years, p less than 0.001), or warfarin alone (9 of 183 [5%], or 1.8/100 patient-years, p less than 0.001). A trend was evident toward a reduction in thromboembolism in the warfarin plus dipyridamole group (2 of 181 [1%], or 0.5/100 patient-years) as compared with warfarin plus aspirin (7 of 170 [4%], or 1.8/100 patient-years), or warfarin alone (6 of 183 [4%], or 1.2/100 patient-years). Adequacy of anticoagulation (based on 12,720 prothrombin time determinations) was similar in all 3 groups with 65% of prothrombin times in the therapeutic range (1.5 less than or equal to prothrombin time/control less than or equal to 2.5), 30% too low, and 5% too high. Warfarin plus aspirin therapy resulted in excessive bleeding and is contraindicated. Longer follow-up study is needed to determine whether further separation of the incidence of thromboembolism can be detected.

Functional Anatomy of the Brachial Plexus Sheaths

Abstract: The brachial plexus sheath was examined in cadavers by using a combination of anatomic dissection, histologic preparations, and x-rays made after injection of x-ray contrast media, and in surgical patients by using computed tomography (CT) dye studies. The connective tissue forming the sheath was organized more densely proximally near its origin and became loosely organized distally as it ended by joining the medial intermuscular septum of the arm. The connective tissue forming the sheath extends inward, forming septa between components of the plexus. Thus, the sheath is a multicompartmented structure, formed by the thin connective tissue sheath surrounding the plexus and by the septa which extend inward from the sheath. A fascial compartment is created for each nerve, and this compartment serves to define the anatomic limits of that nerve. These compartments have potential clinical importance and implication in the techniques for brachial plexus block. They serve functionally to limit the circumferential spread of injected solutions of local anesthetics. These studies also indicate that injected anesthetic solutions spread easily in a longitudinal manner up and down the nerve and remain compartmentalized. The data presented here provide a rational explanation for the not uncommon occurrence of a profound block of rapid onset in one nerve, yet partial or absent block in other nerves, following any of the techniques of brachial plexus anesthesia.

Passive transfer of Lambert-Eaton myasthenic syndrome with IgG from man to mouse depletes the presynaptic membrane active zones.

Abstract: In the Lambert-Eaton myasthenic syndrome (LEMS), there is a decreased release of acetylcholine quanta from the nerve terminal by nerve impulse. Recently, an autoimmune origin of LEMS was documented by passive transfer of its electrophysiologic features from man to mouse with IgG. Freeze-fracture electron microscopy of LEMS neuromuscular junctions has revealed a paucity of presynaptic membrane active zones. Thus, the active zones might be the targets of the pathogenic autoantibodies in LEMS. To test this assumption, freeze-fracture electron microscopic studies were done in mice injected with 10 mg of IgG daily from each of three LEMS patients and in control mice treated with normal human IgG or no IgG. IgG from patients 1 and 2 impaired neuromuscular transmission in mice, but IgG from patient 3 failed to do so. After 52-69 days of treatment, diaphragm or anterior tibial muscles were removed and coded. Paired muscles from control mice and mice receiving LEMS IgG were studied "blindly." Satisfactory freeze-fracture replicas of 185 presynaptic membrane P-faces were analyzed by stereometric methods. In mice treated with LEMS IgG that was pathogenic by electrophysiologic criteria, there was a selective depletion of active zones and active-zone particles but not of other membrane particles and there was a concomitant increase of large membrane particles aggregated into clusters. These findings provide additional evidence that the active zones facilitate quantal transmitter release by nerve impulse, lend further support to the assumption that the active-zone particles are Ca2+ channels, and establish mediation of the membrane lesions in LEMS by IgG.

Osteosclerotic myeloma and peripheral neuropathy

Abstract: Sixteen cases of osteosclerotic myeloma and peripheral neuropathy (SM-PN) were reviewed. The neuropathy resembled chronic inflammatory-demyelinating polyneuropathy with predominantly motor disability, high CSF protein levels, and low motor nerve conduction velocities. Twelve of the 16 patients had detectable levels of monoclonal serum proteins, all with A light chains, but results of other laboratory studies were usually normal. Most of the patients also had organomegaly, endocrine abnormalities, or both. Treatment of solitary lesions with tumoricidal irradiation usually improved the neuropathy and reversed the nonneurologic abnormalities; chemotherapy for multiple osteosclerotic lesions was less helpful.

Infection after Total Elbow Arthroplasty

Abstract: Deep sepsis occurred after fourteen (9 per cent) of 156 elbow-replacement procedures in 140 patients. This high frequency of infection was attributed to several factors. First, the patients were drawn from a population that was at high risk of infection, because rheumatoid arthritis and post-traumatic arthritis were the indications for arthroplasty. Second, many of the patients had had prior surgery, which significantly (p less than 0.02) increased the risk of sepsis in those with rheumatoid arthritis. Third, some patients had surgery after the arthroplasty, which also seemed to predispose to deep infection (p less than 0.05). In one patient the elbow was salvaged by early debridement, and in two others reimplantation of a total joint replacement was successful after removal of the first prosthesis and control of the infection. Resection arthroplasty was required to arrest the infection in ten patients, eight of whom had a satisfactory result. The high incidence of this significant complication attests to the hazardous nature of the elbow-replacement procedure and should warn orthopaedic surgeons to be cautious when recommending this form of treatment.

Surgical Treatment of Incidental Intracranial Aneurysms

Abstract: It is clear that more incidental aneurysms will be encountered in the future. Approximately 5% or more of the population harbors these lesions, and advancing technology can be expected to demonstrate them with increasing regularity. Multiple aneurysms will also be found in at least 18% of patients with subarachnoid hemorrhage due to aneurysms. The best estimates suggest a rate of hemorrhage approximating 1%/year for incidental aneurysms and a 0.4 to 0.65% annual mortality rate for these lesions. It has also been shown that even small aneurysms may enlarge and bleed unpredictably with the passage of time. Surgery for incidental aneurysms of the anterior circulation can be accomplished without mortality and with an operative morbidity of 6.5%. Higher morbidity occurs in surgery for aneurysms in more difficult locations as well as larger aneurysms. The increased risk of bleeding from larger aneurysms, however, may justify the increased morbidity of surgery for these lesions. Surgery for incidental aneurysms can be recommended in healthy individuals whose anesthetic risk is acceptable and for aneurysms less than 1.5 cm in diameter arising from the middle cerebral and posterior communicating arteries. Advancing age alone is not a contraindication for surgery, nor is size greater than 1.5 cm in diameter; however, the latter factor increases the operative risk. Operations to clip aneurysms of the carotid bifurcation, carotid-ophthalmic, and anterior communicating arteries may also be recommended, but these aneurysms are more difficult to approach and surgery carries a higher morbidity. Larger aneurysms, greater than 1.5 cm in diameter, in patients over 60 years of age, and in less accessible locations may not benefit from operation because surgical morbidity for these lesions is high and with advancing age the lifetime risk of rupture has decreased. For incidental aneurysms of the posterior circulation there are insufficient data to make a recommendation regarding surgery, although it is anticipated that the counsel for anterior circulation aneurysms will apply. If operative mortality and morbidity are to be maintained at acceptable levels, incidental aneurysm surgery should be the province of the accomplished aneurysm surgeon who has available to him the most modern techniques and equipment. With the clipping of incidental aneurysms, hopefully the number of patients suffering from subarachnoid hemorrhage with its high morbidity and mortality rates can be further reduced.

Circulation to Skeletal Muscle

Abstract: The sections in this article are: 1 Basal Vascular Resistance and Autoregulation 2 Role of Myogenic Mechanism in Reactive Hyperemia 3 Role of Myogenic Mechanism in Exercise Hyperemia 4 Types of Skeletal Muscle Fibers 5 Muscle Blood Flow During Exercise 5.1 Oxygen Lack 5.2 Lactic Acid, pH, and CO2 5.3 Potassium 5.4 Inorganic Phosphate 5.5 Osmolarity 5.6 Prostaglandins 5.7 Adenosine and Adenine Nucleotides 5.8 Intrinsic Neurons and Exercise Dilatation 5.9 General Conclusions 6 Mechanical Hindrance to Blood Flow in Skeletal Muscle 7 Reactive Hyperemia 7.1 Are Exercise and Reactive Hyperemia Due to the Same Mechanism(s)? 8 Propagated Vasodilatation 9 Sympathetic Vasomotor Outflow 10 Noradrenergic Innervation of Resistance Vessels in Muscles 10.1 Neuroeffector Junction 10.2 α-Adrenergic Activation 11 Factors that Modulate Transmitter Output From Sympathetic Nerve Endings 11.1 Metabolic Action 11.2 Neurohumoral Action 12 Reflex Regulation of Skeletal Muscle Resistance Vessels by Sympathetic Noradrenergic Nerves 12.1 Carotid and Aortic Baroreflex 12.2 Carotid and Aortic Chemoreflex 12.3 Reflexes From the Heart and Lungs 12.4 Diving Reflex 12.5 Reflex From Receptors in Skeletal Muscles 13 Rhythmic Exercise 14 Isometric Exercise 15 Influence of Sympathetic Noradrenergic Fibers on the Blood Flow to Active Muscles 16 β2-Adrenergic Activation 17 Cholinergic Vasodilator Nerves 17.1 Role of Cholinergic Nerves in the Carotid Baroreflex 17.2 Cholinergic Vasodilatation in Humans 18 Histaminergic Vasodilatation 18.1 Role of Histamine in the Vasodilatation Resulting From Reflex Inhibition of Sympathetic Outflow 19 Conclusions

Papillary muscle rupture complicating acute myocardial infarction: analysis of 17 patients

Abstract: The records of 17 patients (10 men and 7 women) with the diagnosis of acute papillary muscle rupture secondary to acute myocardial infarction (AMI) were reviewed to determine the clinical course and pathologic features of this entity. Eight patients underwent operation after papillary muscle rupture had been diagnosed, and 9 had the diagnosis confirmed at autopsy without a prior surgical procedure. The ages were 44 to 80 years (mean 64). The site of AMI was inferolateral in 15 and anterior in 2. The recorded onset of mitral regurgitation ranged from less than 24 hours to 28 days after AMI (mean 6 days). Of the 11 patients presenting with pulmonary congestion alone, 6 remained stable and had subsequent mitral valve replacement and coronary artery bypass graft operation; however, 5 patients' condition initially stabilized with medical therapy and then suddenly deteriorated after a variable period (1 to 60 days), followed by death. Of the 6 patients who presented with systemic hypotension and pulmonary congestion, 4 were treated medically and died; 1 of the 2 who had surgical treatment survived. The extent of the AMI at autopsy was small and was limited to the subendocardium in half of the patients. Significant coronary artery disease was limited to a single vessel in 7 of 14 patients. The unpredictable and rapid clinical deterioration and the limited extent of coronary atherosclerotic disease and infarct size suggest that early surgical repair should be undertaken in patients with papillary muscle rupture after AMI.