Interaction of pergolide with central dopaminergic receptors.

The activity of pergolide, an N-propylergoline derivative, has been tested for stimulation of central dopaminergic receptors. Binding to dopamine receptors shows that pergolide acts as an agonist with respect to these receptors. GTP decreases the potencies of dopamine agonists and of pergolide, but not of bromocriptine, to displace [3H]spiroperidol ([3H]Spi) from striatal membrane sites. The GTP-sensitive site labeled by [3H]Spi seems to be localized on intrastriatal dopamine receptors. The potency of dopamine agonists and of pergolide to displace [3H]Spi from striatal receptor sites is reduced in membranes exposed to higher temperatures. Pergolide, but not hitherto-tested dopaminergic ergots, stimulates dopamine-sensitive adenylate cyclase in striatal homogenates. Thus, pergolide, unlike other dopaminergic ergots, acts as an agonist on GTP-sensitive components of [3H]Spi binding and stimulates dopamine receptors linked to dopamine-sensitive adenylate cyclase. The drug also induces turning behavior in rats with 6-OH-dopamine lesions and relieves tremor in monkeys with ventromedial tegmental lesions for a longer time at a lower dose than other tested dopaminergic ergots. Other studies have shown that it is effective in the treatment of patients with advanced parkinsonism.     

Physiologic categorization of asbestos-exposed workers

Categorization of the pattern of physiologic abnormalities in patients with asbestos-associated disease may be important for clinical, compensation, and epidemiologic reasons. A population of 658 asbestos-exposed workers was divided into six groups (restrictive, mixed restrictive-obstructive, obstructive, abnormal diffusing capacity, small airway disease, and normal) based upon pulmonary function test results. Use of two commonly employed prediction equations for diffusing capacity produced divergent results. Adjustment of the forced vital capacity for airtrapping based upon measurement of residual volume or of total lung capacity can improve the accuracy of categorization, particularly in smokers. Hence, the process of interpretation of pulmonary function testing should be chosen carefully.     

Mortality and morbidity rates of patients older and younger than 75 years with acute myocardial infarction treated with intravenous streptokinase

The influence of patient age on mortality risk and on the incidence of serious hemorrhagic complications after treatment of acute myocardial infarction (AMI) with intravenous streptokinase (SK) and heparin was examined in 120 consecutive patients. No upper age limit was set for patient inclusion. The mortality rate increased abruptly in patients aged 75 years or older such that the 24 patients in that age group had a 10-fold higher in-hospital mortality rate (33% vs 3%) and 1-year mortality rate (42% vs 4%) than the 96 patients younger than 75 years. This increased mortality rate in the elderly patients was related to a 2-fold higher incidence of major hemorrhagic complications (24% vs 11%) and an increased incidence of anterior AMI, healed prior AMI, multiple-vessel coronary artery disease and extensive myocardial necrosis estimated by peak creatine kinase-MB. Hemorrhagic complications were more frequent in women than in men and in patients with diabetes mellitus or systemic hypertension; all of these conditions were more prevalent in patients aged 75 years and older than in those younger than 75 years. In contrast, the incidence of hemorrhagic complications in nondiabetic elderly men (1 of 12) was similar to the incidence of bleeding in the patients younger than 75 years. Based on our data and those from other studies reporting no reduction in mortality in elderly patients with AMI who are treated with intravenous SK, it is recommended that patients aged 75 years or older should not be routinely treated with intravenous SK.(ABSTRACT TRUNCATED AT 250 WORDS)     

Association of hospital and surgeon volume of total hip replacement with functional status and satisfaction three years following surgery

OBJECTIVE: To evaluate whether hospital volume and surgeon volume of total hip replacements (THRs) are associated with patient-reported functional status and satisfaction with surgery 3 years postoperatively. METHODS: We performed a population-based cohort study of a stratified random sample of Medicare beneficiaries who underwent elective primary or revision THR in Ohio, Pennsylvania, or Colorado in 1995. The primary outcomes were the self-reported Harris hip score and a validated scale measuring satisfaction with the results of surgery. Both outcomes were assessed 3 years postoperatively. Hospital volume was defined as the aggregate number of elective primary and revision THRs performed on Medicare beneficiaries in the hospital in 1995. High-volume hospitals were defined as those in which >100 such procedures are performed annually, and low-volume centers were defined as those in which 12 procedures per year. CONCLUSION: Hospital volume and surgeon volume have little effect on 3-year functional outcome following THR, after adjusting for patient sociodemographic and select clinical characteristics. However, satisfaction with primary THR is greater among patients who underwent surgery in high-volume centers, and satisfaction with revisions is greater among patients whose operations were performed by higher-volume surgeons. Referring clinicians should incorporate these findings into their discussion of referral choices with patients considering THR. Conclusions regarding the effect of volume on longevity of the implants must await longer-term followup studies. Finally, further research is warranted to better understand the association between hospital and surgeon procedure volume and patient satisfaction with surgery.     

Anomalous origin of the left circumflex coronary artery from the right aortic sinus: A familial clustering

Origin of the left circumflex coronary artery from the right sinus of Valsalva or the right coronary artery is a well-described anomaly. We report 3 cases which suggest a familial association of this anomaly. The familial clustering that we report has not been previously demonstrated. © 1993 Wiley-Liss, Inc.     

Mummification of the infarcted myocardium by high dose corticosteroids

There is evidence that glucocorticoids reduce infarct size but their use in myocardial infarction remains controversial because of their potential adverse effects on healing of the infarct. To investigate the healing process, rats received either four parenteral doses of 50 mg/kg of methylprednisolone (MP) or saline 5 min, 3,6 and 24 hr after coronary occlusion and their hearts were examined by light and electron microscopy 48 hr and seven days after occlusion. At 48 hr, in five untreated rats, only 12 +/- 7% of injured myocytes showed the persistence of striations and a relatively intact sarcolemma despite loss of nuclei and hence appeared "mummified" whereas in six MP-treated rats 72 +/- 8% of myocytes exhibited this appearance (P less than 0.001). In treated rats there were fewer phagocytes than in controls. At seven days, in seven MP-rats, mummified cells were still more prominent than in five untreated rats and there were fewer phagocytes and less collagen. In conclusion, high dose of MP delays the inflammatory process and retards the disintegration of necrotic myocytes, resulting in impaired healing.     

Usefulness of residual plasma fibrinogen after intravenous streptokinase for predicting delay or failure of reperfusion in acute myocardial infarction

The relation between the level of residual plasma fibrinogen and coronary artery reperfusion after 750,000 IU of intravenous (i.v.) streptokinase (SK) was examined in 76 patients with acute myocardial infarction. Both the frequency and rapidity of reperfusion were greater in the 53 patients in whom the residual fibrinogen level was 50 mg/dl or less (low fibrinogen) than in the 23 patients in whom it was more than 50 mg/dl (high fibrinogen). Reperfusion occurred in all 53 patients in the low-fibrinogen group, compared with only 15 patients in the high-fibrinogen group (p less than 0.001). The interval from initiation of SK to clinical signs of reperfusion was 50 +/- 34 minutes in the low-fibrinogen group and 110 +/- 54 minutes in the high-fibrinogen group (p less than 0.001). A high fibrinogen level occurred in 58% of patients who weighed more than 85 kg and in 25% of patients who weighed 85 kg or less (p less than 0.05). No patient who weighed 60 kg or less had a high fibrinogen level. The high-fibrinogen group also had a greater incidence of a high anti-SK antibody titer: 8 of 13 patients (62%) tested, compared with none of the 8 patients tested in the low-fibrinogen group (p less than 0.01). Our data indicate that a high residual fibrinogen level after administration of i.v. SK identifies patients in whom SK is relatively ineffective, probably because of inadequate dosage of inactivation of the drug.(ABSTRACT TRUNCATED AT 250 WORDS)     

Accelerated idioventricular rhythm detected during elective surgery in a healthy man.

Accelerated idioventricular rhythm (AIVR) is found most commonly in the presence of underlying heart disease. It is characterized by acceleration of a latent pacemaker that normally depolarizes slowly. We describe a 30-year-old man who was found to have episodes of accelerated idioventricular rhythm (AIVR) on cardiac monitoring during elective orthopedic surgery. Noninvasive evaluation including two-dimensional echocardiography was unremarkable. No late potentials were detected on a signal-averaged electrocardiogram. During an exercise tolerance test, AIVR was suppressed as heart rate increased. A 24-h Holter monitor revealed that the AIVR rate was consistently 73-76 beats/min, which appeared whenever the sinus rate slowed to this level. The patient has been asymptomatic, and the rhythm has persisted at least through a 5-month follow-up period.