123rc/medical_text huggingface dataset:
Mechanisms of blood flow during pneumatic vest cardiopulmonary resuscitation. Mechanisms of blood flow during cardiopulmonary resuscitation (CPR) were studied in a canine model with implanted mitral and aortic flow probes and by use of cineangiography. Intrathoracic pressure (ITP) fluctuations were induced by a circumferential pneumatic vest, with and without simultaneous ventilation, and by use of positive-pressure ventilation alone. Vascular volume and compression rate were altered with each CPR mode. Antegrade mitral flow was interpreted as left ventricular (LV) inflow, and antegrade aortic flow was interpreted as LV outflow. The pneumatic vest was expected to elevate ITP uniformly and thus produce simultaneous LV inflow and LV outflow throughout compression. This pattern, the passive conduit of "thoracic pump" physiology, was unequivocally demonstrated only during ITP elevation with positive-pressure ventilation alone at slow rates. During vest CPR, LV outflow started promptly with the onset of compression, whereas LV inflow was delayed. At compression rates of 50 times/min and normal vascular filling pressures, the delay was sufficiently long that all LV filling occurred with release of compression. This is the pattern that would be expected with direct LV compression or "cardiac pump" physiology. During the early part of the compression phase, catheter tip transducer LV and left atrial pressure measurements demonstrated gradients necessitating mitral valve closure, while cineangiography showed dye droplets moving from the large pulmonary veins retrograde to the small pulmonary veins. When the compression rate was reduced and/or when intravascular pressures were raised with volume infusion, LV inflow was observed at some point during the compressive phase. Thus, under these conditions, features of both thoracic pump and cardiac pump physiology occurred within the same compression. Our findings are not explained by the conventional conceptions of either thoracic pump or cardiac compression CPR mechanisms alone.
Atopy and primary lung cancer. Histology and sex distribution. Atopy, defined as the ability to develop IgE antibodies to commonly encountered allergens under conditions of normal exposure, has an inherited component with pleiotropic effects. An inverse relationship between the occurrence of atopy, allergy-related diseases, and cancers at specific sites has been reported. The familial association of primary lung cancer is most evident among women, nonsmokers, and those with adenocarcinomas. In order to determine whether the relationship between a lower prevalence of atopy among patients with lung cancer compared to control subjects was consistent between histologic cell types, we used seven common allergens to allergy prick skin test 209 community control subjects (46 women), 109 cases with primary squamous cell carcinoma of the lung (25 women), and 67 patients with primary adenocarcinomas of the lung (23 women). We have confirmed earlier reports of an inverse relationship between atopy and lung cancer risk. In analyses focusing on sex and histologic cell type, we found that women with adenocarcinomas were an exception and were as likely to be atopic as control subjects. The evidence does not support a protective role for atopy among these women.
Cat-scratch disease: an unusual cause of combative behavior. Acute encephalitis is an unusual manifestation of cat-scratch disease. The authors present the case of a 27-year-old man who exhibited the acute onset of encephalitis manifested by violent behavior and confusion. The diagnosis of drug abuse was presumed initially, but a careful examination revealed the true cause to be cat-scratch disease. Emergency physicians are frequently faced with the challenging task of evaluating confused and combative patients. This case demonstrates the importance of a complete physical examination and a thorough laboratory evaluation.
A prospective study of patients with sciatica. A comparison between conservatively treated patients and patients who have undergone operation, Part II: Results after one year follow-up. The prospective study included 122 sciatica patients who had not undergone operation (NOPs) and 220 sciatica patients who had undergone operation (OPs); all had been examined by rhizography. The follow-up study was done on 110 (90%) of the NOPs and 212 (96%) of the OPs. The NOPs were divided into two groups: 30 patients with pathologic rhizography (PR) and 80 patients with negative rhizography (NR). Pain-, ADL-, and occupation-handicap indices showed that after the 1 year follow-up the OP group had the best result and the NR group the lowest result. The PR group had nearly as good a result as the OP group. Thus, sciatica patients are candidates for conservative therapy, even though they have pathologic findings in rhizography, if the symptoms are mild. To improve therapeutic outcome, more accurate diagnostic tools are needed to develop specific therapy especially for those sciatica patients with negative rhizography.
Infrainguinal bypass surgery: factors determining late graft patency. The results of 373 infrainguinal bypass grafts, in a single centre, between 1980 and 1988 are reviewed. One hundred and thirty in situ vein (ISV), 47 reversed saphenous vein (RSV), 118 polytetrafluoroethylene (PTFE) and 78 human umbilical vein (HUV) grafts were used. The indications for surgery were disabling claudication in 25 per cent of patients and limb salvage in 75 per cent. In 36 per cent of operations the distal anastomosis was above the knee and in 64 per cent it was below the knee. Overall 5-year patency rates and limb salvage rates respectively were, for ISV (41 and 69 per cent), RSV (62 and 90 per cent), PTFE (31 and 67 per cent) and HUV (29 and 59 per cent). There was no significant difference in patency among these grafts at the above-knee level, but significant differences between vein and prosthetic grafts were evident below the knee (P less than 0.001). Using a proportional hazards model the three factors that consistently correlated with late graft patency were graft type (P less than 0.001), site of distal anastomosis (P less than 0.001) and distal run-off (P less than 0.001). Overall, the results suggest that prosthetic grafts are a suitable alternative to autogenous vein when the distal anastomosis is above the knee, but vein should always be used, if available, below the knee joint.
Improved early detection of recurrence in prostatic carcinoma following hormonal therapy. Combined use of palpation and fine needle aspiration cytology. Fifty-nine hormonally treated prostatic carcinoma patients were prospectively followed by rectal examination and fine needle aspiration cytology at six-month intervals for periods ranging from six to one hundred twenty months (median follow-up 48 mos). The cytologic findings and clinical impressions were divided into four or five categories, respectively, ranging from benign to clearly malignant. Cytologic material and clinical descriptions suitable for evaluation were available for 306 follow-up examinations. Of these, 209 were cytologically benign (including 191 without and 18 with clinical evidence of malignancy). The remaining 97 examinations showed cytologic evidence of malignancy of which 50 were clinically apparent (51.5%). While the correlation of clinical and cytologic findings was good (91.4%) in cases with no evidence of disease activity, our findings indicate that many recurrences which are occult to clinical examination may be detected by cytologic examination.
Improved flow cytometric determination of proliferative activity (S-phase fraction) from paraffin-embedded tissue. Recent studies suggest that proliferative activity (S-phase fraction [SPF]) may have greater prognostic significance than total nuclear DNA content; however, relatively few studies have examined SPF from paraffin-embedded tissue because of significant contamination of histograms with debris. In this study, cell cycle analysis was performed on 124 matched tissue specimens. Fresh tissue was divided into two equal portions; one portion was frozen, whereas the other portion was processed and embedded in paraffin. S-phase could be determined for both frozen and paraffin-embedded tissue in 81 cases. Correlation between SPF from frozen and paraffin-embedded tissue was demonstrated (r = 0.80) when debris was subtracted from histograms with the use of two new subtraction algorithms referred to as multicut and singlecut. Unlike other debris-subtraction algorithms, the quantity and distribution of debris calculated by these algorithms are dependent on the magnitude and position of histogram peaks. A lesser degree of correlation was demonstrated with the use of a standard exponential debris subtraction algorithm (r = 0.67). Correlation of SPF for aneuploid cases was greater when SPF was calculated as a percentage of the aneuploid cell population rather than as a percentage of the entire cell population. This was attributed to the observation that the proportion of aneuploid cells from paraffin-embedded tissue was less than that from frozen tissue. The results of this study indicate that SPF can be calculated from paraffin-embedded tissue with values comparable to those obtained from frozen tissue. The ability to calculate SPF reliably from paraffin-embedded tissue should allow additional evaluation of this parameter as a prognostic indicator.
Patient factors predicting early alcohol-related readmissions for alcoholics: role of alcoholism severity and psychiatric co-morbidity. The current study was undertaken primarily to identify whether psychiatric co-morbidity was associated with the rate and time of alcohol-related inpatient readmissions for a group of 255 patients discharged from alcoholism treatment at a midwestern rural medical center. A structured interview obtained information regarding psychiatric disorders, including depression, antisocial personality disorders and polysubstance abuse, as well as alcohol history and sociodemographics. Ninety-eight subjects (38.4% of sample) were readmitted for alcoholism-related diagnoses within 15 months of discharge. Patients with a long history of heavy drinking, high daily alcohol consumption and history of previous alcoholism treatment were most likely to be readmitted with an alcoholism-related primary diagnosis. Once these variables were controlled for, other major psychiatric disorders, polysubstances abuse and sociodemographic variables did not appear to predict time to readmission. However, other potentially more sensitive outcome measures such as return to drinking were not evaluated in the present study.
Patients with two types of atrioventricular junctional (AV nodal) reentrant tachycardia. Evidence that a common pathway of nodal tissue is not present above the reentrant circuit. BACKGROUND. The site of the reentrant circuit in atrioventricular (AV) junctional reentrant tachycardia has not been defined; in particular, the existence of a common pathway of AV nodal tissue above the reentrant circuit is controversial. METHODS AND RESULTS. Two types of AV junctional reentrant tachycardia were induced in each of three patients at electrophysiological study. In one type of tachycardia (anterior), the onset of atrial activity occurred from 0 to 12 msec before the onset of ventricular activation, and earliest atrial activity was recorded near the His bundle. In the second type of tachycardia (posterior), the ventriculoatrial intervals were longer (76-168 msec), and earliest atrial activity was recorded near the mouth of the coronary sinus. In individual patients, the two types of tachycardia had different cycle lengths. Posterior AV junctional reentrant tachycardia was not a fast-slow form of AV junctional reentry in at least two of the three patients. Surgical cure was attempted in two patients. In one patient, anterior AV junctional reentrant tachycardia was abolished by dissection of the anterior perinodal atrium, but posterior AV junctional reentrant tachycardia could still be induced. At reoperation 4 months later, dissection of the posterior perinodal atrium abolished posterior AV junctional reentrant tachycardia while preserving AV conduction. CONCLUSION. Differences in ventriculoatrial intervals and cycle lengths and the results of selective surgery suggest that the two types of AV junctional reentrant tachycardia used different reentrant circuits. These observations imply that a common pathway of AV nodal tissue is not present above the reentrant circuit and suggest that perinodal atrium is part of these circuits.
Pain control in the ambulatory elderly. Pain control in the elderly, no matter what the etiology or setting, can be a major clinical challenge. Aging causes unique physiologic changes, eg, a decreased perception of pain and an enhanced sensitivity to opioid analgesics. Principles regarding evaluation of patients with pain are reviewed, including the use of an objective instrument for pain assessment from the viewpoint of both physician and patient. Good pain control can be achieved with the nonopioids, such as acetaminophen and the nonsteroidal anti-inflammatory drugs, the opioid analgesics, and, in some cases, adjuvant agents. Discussed also are the concerns for patient addiction and the WHO Cancer Pain Relief program.
Disseminated zygomycosis associated with systemic lupus erythematosus. We describe a 36-year-old patient who had systemic lupus erythematosus (SLE) and died of disseminated zygomycosis. There was rapid progression of his SLE, leading to suspicion of superimposed infectious disease, but the actual cause of his multiorgan failure was not recognized until after death. The manner in which systemic fungal infection may mimic SLE is discussed.
Angiotensin-converting-enzyme inhibitors and anaphylactoid reactions to high-flux membrane dialysis In a retrospective study, 9 of 236 haemodialysis patients treated with high-flux polyacrylonitrile 'AN 69' membranes were found to have had anaphylactoid reactions. Treatment with angiotensin-converting-enzyme (ACE) inhibitors had been recently started in all 9 affected patients; only 5 of 227 unaffected patients had been treated with ACE inhibitors, and anaphylactoid reactions disappeared after discontinuation of ACE inhibitors.
Prospective pharmacokinetically based development of effective infusion regimens for ACC-9358, a new antiarrhythmic drug. In this study we evaluated the clinical pharmacology of intravenous ACC-9358, a new antiarrhythmic drug derived from a Chinese herbal remedy. In a first-study phase, 0.125 to 1.0 mg/kg during 10 minutes was administered to six patients with chronic nonsustained ventricular arrhythmias. These data were then used to design 3-hour infusions to maintain stable plasma concentrations: these infusions suppressed arrhythmias by 90% or greater for 2 1/2 hours or more at plasma concentrations of 114 to 1010 ng/ml (mean, 400 +/- 421 ng/ml [SD]), and with QRS interval increases of 2.5% to 8.8% (5.1% +/- 2.9%). Mean clearance was 478 +/- 151 ml/min, and elimination half-life was 19.1 +/- 6.1 hours. ACC-9358 did not produce adverse effects in this study. ACC-9358 shows antiarrhythmic activity in humans at concentrations that prolong QRS only slightly and do not alter rate-corrected QT; further studies in other patient populations, at dosages and plasma concentrations defined here, are required to establish a clinical role for ACC-9358. The pharmacokinetically based dose-ranging approach allowed the safe initial evaluation of ACC-9358 in patients.
Adrenal hormones and the anorectic response and adaptation of rats to amino acid imbalance. The role of adrenal function in the anorectic response and adaptation of rats to a diet with an isoleucine (Ile) imbalance was investigated. In the first of four experiments, rats were fed a mildly Ile-imbalanced diet after treatment with metyrapone, and inhibitor of glucocorticoid synthesis. In two separate experiments, rats were presented with either a mildly or severely Ile-imbalanced diet (4.93 and 9.86% imbalanced amino acid mixture, respectively) after bilateral adrenalectomy. Finally, the effects of ICS 205-930, a serotonin-3 receptor antagonist, on the intake of mildly Ile-imbalanced diet were tested in adrenalectomized animals. In each experiment a 2 X 2 factorial design was used. Neither metyrapone nor adrenalectomy altered the initial depression in the intake of an imbalanced diet. The adaptation phase in the response of adrenalectomized rats fed a mildly Ile-imbalanced diet was not different from that of controls, but adrenalectomized rats fed severely Ile-imbalanced diets were unable to adapt. Adrenalectomy did not alter the anti-anoretic activity of ICS 205-930 in this model. These results suggest that adrenal hormones are not necessary for the initial anoretic response or adaptation of rats to an Ile-imbalanced diet, nor are they implicated in the anti-anorectic effect of serotonin-3 blockade.
Assessment of myocardial perfusion in patients after the arterial switch operation. In 21 patients who had undergone the arterial switch operation, the adequacy of myocardial perfusion was evaluated by thallium-201 computed scintigraphy 2.6 +/- 2 (0.3-7) yr after surgery. Fourteen patients had undergone the arterial switch procedure after pulmonary artery banding and seven as a primary repair. Isoproterenol stress increased the heart rate by at least 55%. Tomographic imaging was performed at peak stress and 3 hr later in the reperfusion phase. Nine patients had perfusion defects. The perfusion defects were located at the left ventricular apex in four (with extension to the inferolateral wall in one), left ventricular anterolateral wall in two, ventricular septum in one, left ventricular inferior wall in one, and right ventricular free wall in one. Some of these defects could be due to myocardial damage at the time of surgery, but these results also raise concern about long-term adequacy of myocardial perfusion following the arterial switch procedure.
Cause of thrombosis in human atherosclerotic arteries. Although it has been known for a long time that thrombosis nearly always develops in atherosclerotic arteries--and almost never in normal vessels--the mechanism through which atherosclerosis promotes thrombosis was unknown until this problem was explored through histologic examination of complete serial section sets of thrombosed atherosclerotic arteries. These studies, repeatedly confirmed, revealed that the thrombi are triggered by microscopic cracks in the collagen cap of advanced plaques. Blood most often seeps from the arterial lumen through the cracks into the underlying lipid gruel before the breaks or cracks are plugged by the thrombi (which function as hemostatic seals of the breaks). These results are parallel to results of experimental studies in which the synergism of endotheliotoxic and pressor agents produced thrombi over cap breaks and sub-break hemorrhages only in arteries with advanced collagen-rich plaques, not in arteries with early atherosclerosis or in normal vessels. This finding indicates that advanced atherosclerosis makes the arterial wall much more fragile and that, once broken, this wall exposes the blood to powerful thrombogenic materials that do not exist in normal arterial tissue. At present, human and experimental evidence suggest that the thrombogenic fissures of advanced plaque caps can be promoted by several factors, such as a surge in intraarterial pressure or insults that damage the caps structurally and increase their vulnerability to any type of stress such as certain metabolic, exogenous chemical and immune insults, spontaneous molecular changes of collagen with time and hemorrhages of capillaries that invade advanced plaques from the adventitia or the arterial lumen.
Respiratory symptoms and risk factors in an Arizona population sample of Anglo and Mexican-American whites. Prevalence rates of respiratory symptoms and diseases in a large group of Anglos and Mexican-Americans were analyzed. Each subject completed a questionnaire. Among current smokers, chronic productive cough and dyspnea were significantly higher in both ethnic groups; wheezy symptoms were higher in Anglos. There were no significant differences in the symptom prevalence rates between the two groups, after stratifying by current cigarette consumption and CRT. The spirometric values were not significantly different. In both ethnic groups, the prevalence rates of wheeze, SOBWHZ and asthma were significantly higher in those who had CRT. Among Anglos, less educated smokers had significantly higher prevalence rates of SOBWHZ and dyspnea; nonsmokers with less education had higher prevalence rates of cough, chronic cough and dyspnea. Our results confirm the importance of CRT and lower educational level as risk factors for respiratory symptoms. Ethnicity is not associated with symptomatology or lung function impairment.
Regeneration of myocardial phosphocreatine in pigs despite continued moderate ischemia. The effects of 1 hour of mild and moderate reductions in coronary blood flow on myocardial high-energy phosphate levels were evaluated. Thirty anesthetized pigs were instrumented with left anterior descending arterial and venous catheters, crystals for instantaneous wall thickness, and a fluid-filled occluder. Measurement of myocardial blood flow was performed with microspheres, and a series of myocardial biopsies also was performed. In 10 pigs, overall coronary blood flow was lowered by 22%, with a fall in subendocardial-to-subepicardial flow ratio from 1.11 to 0.54 and in wall thickening from 33% to 15%. Subendocardial flow fell 48%. Coronary blood flow and thickening were constant during 1 hour of ischemia. Phosphocreatine (mumol/g wet wt) in the subendocardial third of the ischemic zone fell from 7.6 to 3.8 at 5 minutes of ischemia (p less than 0.005 versus control) and returned to normal (7.9) at 60 minutes (p = NS), despite ongoing ischemia. Subendocardial ATP (mumol/g wet wt) fell slowly from 4.3 and leveled off at 2.1 at 60 minutes of ischemia (p less than 0.001 versus control). Similar regeneration of phosphocreatine was found in seven additional pigs, with a 43% transmural reduction in coronary blood flow and a 66% reduction in subendocardial flow. No significant changes in ATP and phosphocreatine were noted in two different control groups (n = 13 pigs). The regeneration of phosphocreatine despite ongoing ischemia and low ATP levels was not related to changes in myocardial oxygen demand or consumption, or in regional function during the period of ischemia. This may reflect 1) a successful downregulation of the energy needs of the ischemic myocardium to maintain cell viability, or 2) a metabolic abnormality in the ability of the cells to produce ATP primarily or by use of phosphocreatine.
Removal of radiation-induced cataracts in patients treated for retinoblastoma. Experience with removal of radiation-induced cataract in patients treated for retinoblastoma is limited. We retrospectively reviewed the records of 38 patients with retinoblastoma (42 eyes) who underwent removal of radiation-induced cataract from 1973 to 1989. Nineteen eyes (45%) without macular tumors or severe radiation complications had final visual acuities in the range of 20/20 to 20/50. One eye (2.4%) developed a rhegmatogenous retinal detachment and four eyes (9.5%) were noted to have amblyopia after cataract removal. Three eyes (7%) developed retinoblastoma recurrence, one with extension of retinoblastoma into the subconjunctival space through the previous sclerotomy. Exenteration was performed and the patient was alive after 8 years. Cataract removal can be visually beneficial in selected patients with radiation-induced cataracts.