123rc/medical_text huggingface dataset:
Atrial activation sequence during atrial flutter in the canine pericarditis model and its effects on the polarity of the flutter wave in the electrocardiogram. Stable atrial flutter induced in both conscious and open chest states was studied in 30 mongrel dogs after production of sterile pericarditis. During the conscious state studies, induced atrial flutter (mean cycle length 128 +/- 15 ms) was always sustained greater than 15 min and was stable. Three types of flutter wave polarity were noted in electrocardiogram (ECG) lead II: positive in 16 dogs, negative in 3 and flat or slightly positive in 11. Sequential site atrial mapping during atrial flutter (mean cycle length 133 +/- 18 ms) in the open chest state showed either clockwise (18 dogs) or counterclockwise (12 dogs) circus movement in the right atrium. In 19 of 30 dogs, the circus movement clearly did not require any naturally existing anatomic obstacle; in 11, the orifice of the superior vena cava probably was also involved. Double potentials were recorded from the center of the reentrant circuit during atrial flutter, and fractionated electrograms were recorded from a pivot point of the reentrant wave front. A positive flutter wave in ECG lead II (12 dogs with counterclockwise circus movement) was associated with early activation of the Bachmann's bundle region compared with the posteroinferior left atrium and activation of the left atrium mainly in a superoinferior direction. A negative flutter was associated with the early activation of the posteroinferior left atrium compared with Bachmann's bundle and activation of a considerable portion of the left atrium in an inferosuperior direction. A flat or slightly positive flutter wave (14 of 18 with clockwise circus movement) was associated with activation of the left atrium almost simultaneously by two wave fronts coming from both these sites. In conclusion, atrial flutter in this dog model is due to circus movement in the right atrium, the center of which does not necessarily require an anatomic obstacle. Although atrial flutter is generated by circus movement in the right atrium, the flutter wave polarity in the ECG is determined primarily by the activation sequence of the left atrium.
Squamous carcinoma of the distal esophagus: a survival study. A survival study for squamous carcinomas of the distal esophagus treated by the Southern California Permanente Medical Group in the interval of 1954 to 1988 was undertaken. We found radiation therapy and surgery equally efficacious in terms of cure for patients without distant disease and performance status sufficient to tolerate treatment. We did not find survival benefit for patients treated with palliative surgery, and plan less invasive endoscopic means along with chemotherapy and radiation for palliation, reserving surgery for special circumstances.
Hypoxanthine levels in vitreous humor: evidence of hypoxia in most infants who died of sudden infant death syndrome. Postmortem changes of the hypoxanthine in vitreous humor in humans were investigated. Hypoxanthine is formed from hypoxic degradation of adenosine monophosphate. Repeated sampling was performed in 13 deceased adults. Keeping the bodies at +6 degrees C, the increase of the hypoxanthine levels was estimated to 3.5 mumol/L per hour when sampling was started more than 12 hours after death (range 2.8 to 5.6 mumol/L per hour). Results of hypoxanthine measurements from vitreous humor in 73 infants with sudden infant death syndrome, 17 infants and children who died sudden violent deaths, and 6 neonates who died suddenly without hypoxemia prior to death were corrected according to the expected postmortem hypoxanthine increase. The time between death and autopsy was similar in the three groups studied. The corrected median hypoxanthine level in the group with sudden infant death syndrome was 227 mumol/L, which is significantly higher than in the other groups; 22 mumol/L in the group who had violent deaths (P less than .01), and 0 mumol/L in the neonate group (P less than .01). The findings seem to confirm that sudden infant death is preceded by a relatively long period of tissue hypoxia in most cases.
Characteristics of a new angiotensin converting enzyme inhibitor: delapril. Delapril, a nonsulfhydryl angiotensin converting enzyme (ACE) inhibitor, which has an indanylglycine moiety differing from the proline moiety of captopril or enalapril, is an esterified prodrug that is converted in vivo to its active metabolites. Delapril effectively inhibits rabbit lung ACE activity and lowers blood pressure in spontaneously hypertensive rats. Delapril has several characteristics that differ from captopril and enalapril, including high lipophilicity and weak bradykinin potentiating action. Delapril is a more potent inhibitor of vascular wall ACE activity than enalapril or captopril. It also shows a weaker potentiating action on the citric acid-induced cough in the guinea pig model compared with captopril and enalapril. In 12 out of 150 patients with essential hypertension who complained of cough during treatment with enalapril, changing to delapril resulted in resolution of the cough in 6 out of 12 of these patients: the percentage of patients in the total population with cough decreased from 8% to 4%.
Coronary angioplasty after coronary bypass surgery: initial results and late outcome in 422 patients. From 1978 to 1988, coronary angioplasty was performed in 422 patients with prior coronary artery bypass surgery (264 patients with native coronary artery angioplasty and 158 patients with graft angioplasty). Angioplasty was successful in 84%, unsuccessful but uncomplicated in 11% and complicated by one or more major cardiac events in 5% (myocardial infarction 5%, emergency bypass surgery 2% and death 0.2%). Follow-up data were obtained in 99% of 356 patients with successful angioplasty. At a mean of 33 +/- 26 months, 92% were alive, 73% had improvement in angina and 61% were free of angina. One or more of the following late events occurred in 67 patients (19%): myocardial infarction (6%), elective reoperation (13%) and cardiac death (6%). Repeat angioplasty was performed in 27%, with a success rate of 89% and no deaths. Initial success rates were equal in native vessel versus graft angioplasty, but late outcome was less favorable with the latter because of a higher rate of infarction (11% versus 4%, p less than 0.05) and need for reoperation (19% versus 10%, p less than 0.05). The initial success rate was higher in vein grafts less than 1 year old compared with grafts 1 to 4 years or greater than 4 years after operation (92% versus 85% versus 83%, respectively) and adverse late events were less frequent after angioplasty in recent vein grafts (less than 1 year 13%, 1 to 4 years 35%, greater than 4 years 29%; less than 1 versus greater than 1 year, p less than 0.05).
Factors influencing survival after pancreaticoduodenectomy for pancreatic cancer. Eighty-nine patients with carcinoma of the head of the pancreas underwent pancreaticoduodenectomies. The actuarial 5-year survival for all 89 patients was 19%, with a median survival of 11.9 months. The 81 hospital survivors were analyzed in an effort to determine factors influencing long-term survival. Negative lymph nodes and the absence of blood vessel invasion both favored long-term survival. The strongest predictive factor was negative lymph node status with a median survival of 55.8 months, compared with 11 months with lymph nodes involved with tumor (p less than 0.05). Blood transfusions were also predictive, with patients receiving two or fewer units having a median survival of 24.7 months, compared with 10.2 months for those receiving three or more units (p less than 0.05). The most important determinant of long-term survival after pancreaticoduodenectomy for pancreatic cancer is biology of the tumor (lymph node status, blood vessel invasion). However, performance of the resection (units of blood transfused) also appears to be an important factor influencing survival.
The effect of continuous epidural analgesia on postoperative pain, rehabilitation, and duration of hospitalization in total knee arthroplasty. Efficacies of three alternate methods of postoperative analgesia were studied in 156 patients who had total knee arthroplasty (TKA). Forty-two of these patients received parenteral meperidine hydrochloride or morphine (Group 1), 58 patients received periodic epidural injections of morphine (Group 2), and 56 patients received continuous epidural infusions of bupivacaine hydrochloride and Duramorph (Group 3). The postoperative course of all patients was documented in terms of the incidence and severity of pain, range of joint motion, duration of hospitalization, and occurrence of complications. Although epidural analgesia increased the cost and duration of the operation, good-to-excellent pain relief was attained in 86% (Group 2) and 88% (Group 3) of cases with epidural analgesia compared with 61% of patients (Group 1) receiving conventional analgesia. Moreover, 67% of patients in Group 1 experienced frequent episodes of moderate-to-severe postoperative pain in contrast to 40% of patients in Group 2 and only 10% of patients in Group 3. As a result of diminished pain, greater joint motion was obtained within the first 72 hours in Groups 2 and 3. They also had shorter hospitalization (9.6 days versus 11.2 days for Group 1 and 10.8 days for Group 2). However, the use of epidural analgesia did not reduce the incidence of complications, including nausea. Continuous infusion of epidural bupivacaine and Duramorph provided good-to-excellent control of postoperative pain after TKA. However, better analgesics are needed to reduce the high incidence of side effects associated with various treatment methods.
Pneumomediastinum, pneumothorax and subcutaneous emphysema following the measurement of maximal expiratory pressure in a normal subject. Mediastinal and subcutaneous emphysema have been reported as a consequence of deliberate manipulations of the breathing pattern producing a Valsalva-like maneuver in healthy subjects. We present a case of pneumomediastinum, pneumothorax and subcutaneous emphysema occurring in a normal volunteer after repeated measurements of the PEmax.
Role of ultrasonic tissue characterization to distinguish reversible from irreversible myocardial injury. Tissue characterization reflects structural and functional integrity of tissues. Inasmuch as reversible ischemia causes no structural damage and irreversible ischemia results in persistent structural myocardial damage, we postulated that ultrasonic tissue characterization can distinguish the two types of injuries. Anesthetized open chest dogs underwent 15 minutes (group 1, n = 5) and 90 minutes (group 2, n = 8) of acute total occlusion of the left anterior descending coronary artery, followed by 3 hours of reperfusion. Myocardial ischemia-infarction was confirmed with segment shortening, electronmicroscopic examination, and triphenyl tetrazolium chloride staining. Integrated backscatter Rayleigh 5 (IBR5), a measure of ultrasonic backscatter, and Fourier coefficient of amplitude modulation (FAM), an index of cardiac cycle dependent variation in backscatter, were measured at baseline, during ischemia, and after reperfusion. Group 1 (reversible ischemia) showed an increase in IBR5 from -48 +/- 1.2 dB at control to -45 +/- 1.0 dB (p less than 0.01) during ischemia, which returned to baseline after reperfusion (-47 +/- 1.3 dB). FAM was blunted during ischemia (6.2 +/- 1.0 dB during control versus 1.2 +/- 1.0 dB during ischemia, p less than 0.01) and recovered completely during reperfusion. Segment shortening was abolished during ischemia (18% +/- 3% during control versus -12% +/- 5% during ischemia, p less than 0.01) and recovered partially during reperfusion (4% +/- 5%). The group 2 animals with irreversible myocardial injury showed an increase in IBR5, from -49 +/- 1.2 dB during control to -44 +/- 1.0 dB during ischemia (p less than 0.01) and paradoxical bulging of the ischemic region (17% +/- 3% to -7% +/- 3%, p less than 0.01) during ischemia.
Nonseminomatous germ cell tumor with very high serum human chorionic gonadotropin. Most patients with disseminated nonseminomatous germ cell tumor (NSGCT) have an excellent prognosis with modern chemotherapy, although certain subgroups with a worse prognosis have been described. One such subgroup includes patients with high serum levels of the tumor marker, human chorionic gonadotropin (HCG). Sixteen patients of 104 treated for NSGCT at the CRC Wessex Medical Oncology Unit (Southampton, UK) presented with serum HCG greater than 25,000. Most of these patients exhibited features of the "choriocarcinoma syndrome" with bulky, rapidly progressive disease; frequent pulmonary, hepatic, and central nervous system complications; and a generally poorer response to standard NSGCT chemotherapy. Histologic identification of trophoblastic tumor was not made in all patients and is not essential for the diagnosis of the syndrome; indeed, closed biopsy may be contradicted in some circumstances because of the risk of hemorrhage. The NSGCT patients with poor prognosis, including patients with the choriocarcinoma syndrome, must be clearly identified in order to improve management and, eventually, cure rates.
The effect of glucose administration on carbohydrate metabolism after head injury. The role of intravenous infusion of glucose in limiting ketogenesis and the effect of glucose on cerebral metabolism following severe head injury were studied in 21 comatose patients. The patients were randomly assigned to alimentation with or without glucose. Systemic protein wasting, arterial concentrations of energy substrates, and cerebral metabolism of these energy substrates were monitored for 5 days postinjury. Both groups were in negative nitrogen balance, and had wasting of systemic proteins despite substantial protein intake. Blood and cerebrospinal fluid (CSF) glucose concentrations were highest on Day 1, but remained higher than normal fasting levels on all days of study, even in the patients who received no exogenous glucose. Although there were no differences in blood or CSF glucose concentrations in the two groups of patients, the glucose group had higher plasma insulin levels, with a mean +/- standard deviation of 14.8 +/- 7.3 microU/ml compared to 10.3 +/- 4.2 microU/ml in the saline group. The blood concentrations of beta-hydroxybutyrate, acetoacetate, pyruvate, glycerol, and the free fatty acids were higher in the saline group than in the glucose group. Cerebral oxygen consumption was similar in the two groups, while the cerebral metabolism of glucose and of the ketone bodies was dependent on whether glucose was administered. In the glucose group, glucose was the only energy substrate utilized by the brain. In the saline group, the ketone bodies beta-hydroxybutyrate and acetoacetate replaced glucose to the extent of 16% of the brain's total energy production. Cerebral lactate production and CSF lactate concentration were lower in the saline group. These studies suggest that administration of glucose during the early recovery period of severe head injury is a major cause of suppressed ketogenesis, and may increase production of lactic acid by the traumatized brain by limiting the availability of nonglycolytic energy substrates.
Experience with esmolol for the treatment of cocaine-associated cardiovascular complications. The authors report their experience using esmolol, an ultra-short acting beta-adrenergic antagonist, for the treatment of seven patients with cocaine-associated cardiovascular complications. No consistent hemodynamic benefit was found with the use of this drug. Although there was a decline in mean heart rate of 23% (range 0% to 35%), they were unable to show a consistent antihypertensive response. Adverse effects occurred in three patients. This included one patient with a marked exacerbation of hypertension and one who became hypotensive. Another patient developed emesis and lethargy during esmolol therapy and required endotracheal intubation. They do not recommend the routine use of esmolol for cocaine cardiotoxicity.
Synchronous carcinoma of the colon and rectum. Reports on the incidence of synchronous carcinoma of the colon and rectum have varied from 2 to 11 per cent. The variability is a result of a lack of uniformity in criteria of diagnosis, differences in the population studied and differences in time period used. In this study, we evaluated the incidence and distribution of synchronous lesions during a recent time period before the use of colonoscopy became widespread. We reviewed the records of all patients with newly diagnosed adenocarcinoma of the colon and rectum who were operated upon at our institution between 1976 and 1981. In a total group of 1,000 patients of which 52 per cent were men, there were 54 patients or 5.4 per cent who had synchronous carcinomas. The group of patients with synchronous carcinomas were older than the group with nonsynchronous carcinomas (72.4 versus 68.8 years). There was also a higher incidence of associated benign polyps in the group with synchronous carcinomas (70 versus 30 per cent for a nonsynchronous carcinomas). The anatomic distribution of carcinomas of the colon and rectum in the group with synchronous lesions (111 in total) revealed a higher percentage of carcinomas located on the right side (29.7 versus 22.5 per cent), although the difference did not reach statistical significance. Synchronous carcinomas were located in nonadjacent segments of the colon in 37 per cent. There was no difference in stage between the groups with and without synchronous carcinomas. The preoperative identification of synchronous lesions by either colonoscopy or barium enema is important for the proper treatment of patients with carcinoma of the colon and rectum. Failure to locate these tumors may lead to the demise of the patient.
Long-term effect of dopaminergic drugs in restless legs. A 2-year follow-up. Thirty patients with restless legs syndrome, who initially had all responded well to treatment with levodopa and benserazide, were studied as to the long-term effect of the drugs (at least 2 years). During the 2-year period, two patients were switched from levodopa to bromocriptine. Two patients no longer needed levodopa; one of them had developed paraplegia and in the other the symptoms of restless legs syndrome had disappeared completely. The remaining 26 patients continued to use levodopa. Eight patients maintained the original dose, nine had to use an increased dose, and nine found a decreased dose to be sufficient. The only side effect was transient nausea reported by two of the 30 patients. The study showed that the relief of symptoms of restless legs syndrome by dopaminergic drugs does not wear off with the passage of time, that side effects are minimal even with long-term use, and that the dose needed to obtain relief may increase as well as decrease.
Leucine kinetics in patients with benign disease, non-weight-losing cancer, and cancer cachexia: studies at the whole-body and tissue level and the response to nutritional support. We have performed intraoperative isotopic infusions of carbon 14-labeled leucine in 65 patients to define the abnormalities in protein metabolism at both the whole-body and tissue level in patients with weight-losing and non-weight-losing cancer. Eighteen patients had benign disease, 26 had non-weight-losing cancer, and 21 had cancer cachexia. Samples of plasma and expired breath were taken to determine rates of whole-body protein synthesis (WBPS), whole-body protein catabolism (WBPC), net protein catabolism, and albumin fractional synthetic rates. Tissue samples were taken to determine the fractional synthetic rates (FSR) of protein in muscle, liver, cancer, and the tissue in which the cancer arose. In addition, in 14 patients the effect of nutritional support on protein metabolism was assessed. In all parameters examined we were unable to detect any significant differences between patients with no cancer and the patients with non-weight-losing cancer. In contrast, patients with cancer cachexia had a significant elevation (p less than 0.005) in WBPC compared with the other two groups. WBPS was also elevated (to a lesser extent) in the patients with cancer cachexia, and the rate of net protein catabolism was increased significantly (p less than 0.05). Patients with cancer cachexia also had significantly higher values of FSR of protein in muscle (p less than 0.05), liver (p less than 0.05), and albumin (p less than 0.01) compared with the other two groups. In addition, the protein FSR in the cancer rose progressively when the values for the primary cancer were compared with those for nodal and systemic metastases. Further, although nutritional support resulted in an increase in host muscle protein synthesis (p less than 0.04), there was no promotion of FSR of protein in cancer. We conclude that patients with cancer cachexia are actively losing protein as a result of an increase in WBPC that is only partially compensated for by an increase in WBPS. There are compensatory increases in protein synthesis in muscle and liver, but these increases in host protein synthesis are insufficient to keep pace with the combined effect of the accelerated rate of protein synthesis in the cancer per se and the accelerated rate of net protein catabolism at the whole-body level. In response to nutritional support, there is a significant increase in the muscle protein synthesis, but we could not demonstrate any increase in cancer protein synthesis.
Prospective randomized multicenter comparison of in situ and reversed vein infrapopliteal bypasses. We have performed a prospective, randomized, multicenter study to compare in situ and reversed vein grafts for long limb salvage bypasses from the proximal thigh to an infrapopliteal artery. Three hundred eighty-four patients required an infrapopliteal bypass for critical lower extremity ischemia. Of these, 259 were excluded because a short vein bypass was performed or because the vein was considered inadequate. The remaining 125 patients had a randomized vein bypass, 63 reversed, 62 in situ. The two groups were similar with regard to risk factors, indications, graft dimensions, and outflow. Secondary patency at 30 months was similar for both techniques: reversed 67% +/- 9% (+/- SE); in situ 69% +/- 8%. For veins less than or equal to 3.0 mm in minimum distended diameter 24-month patency rates were 61% +/- 22% for 12 in situ veins and 37% +/- 29% for 10 reversed veins (p greater than 0.05). Angiographic evaluation of failing grafts revealed lesions similar in type and frequency in both types of grafts. These included focal (in situ, n = 4; reversed, n = 7) and diffuse vein hyperplasia (in situ, n = 2; reversed, n = 1), and inflow and outflow stenoses (in situ, n = 4; reversed, n = 3). The incidence of wound complications and the mortality rate were similar for the two groups. These data show no significant difference in overall patency rates for the two types of vein grafts at 2 1/2 years.