123rc/medical_text huggingface dataset:
Disposition of cerebral metastases from malignant melanoma: implications for radiosurgery Radiosurgery is becoming more generally available and indications for its use continue to be defined. Cerebral metastases from malignant melanoma are often treated with whole-brain irradiation, but with limited benefit. Innovative treatments, such as radiosurgery, make possible the delivery of doses of radiation that are higher than usual. To determine how many patients might be candidates for radiosurgery, a retrospective analysis of computed tomographic brain scans performed on 41 patients with cerebral metastases from malignant melanoma was undertaken. One-third of these patients were found to have cerebral metastases amenable to a radiosurgical approach, as illustrated radiation dose-volume histograms. Patient and tumor characteristics suggest that this series is represent with cerebral metastases from malignant melanoma. The implications of radiosurgery for normal tissue radiation tolerance and its effects on melanoma are discussed.
Genetics of asthma and hay fever in Australian twins. The occurrence of self-reported asthma/wheezing and hay fever among 3,808 pairs of twins from the Australian National Health and Medical Research Council Twin Registry was examined for evidence of genetic transmission by path analytic methods. The cumulative prevalence of asthma or wheezing was 13.2% and of hay fever, 32%. There were significant correlations in liability to reported disease among twins, and these were higher in monozygotic twins (MZ) (r = 0.65) than in dizygotic twins (DZ) (r = 0.25), and in male MZ twins (r = 0.75) compared with female MZ twins (r = 0.60). Analysis under the assumptions of the classic twin model suggested that there were genetic factors common to asthma and hay fever, with a correlation in genetic liability to the traits of 0.52 for men and 0.65 for women. These genes acted substantially in a nonadditive fashion in men but not in women. As the genetic correlation was significantly less than unity, this implied additional genetic factors influencing either or both diseases individually. The estimated heritability of these diseases was 60 to 70% in this population. Environmental causes of both diseases also were correlated (r = 0.53 for men and 0.33 for women). Cigarette smoking was only weakly associated with wheezing.
Changes in plasma free fatty acids and glycerols during prolonged exercise in trained and hypertensive persons taking propranolol and pindolol. The extent to which lipolysis is attenuated during prolonged submaximal exercise during beta blockade was determined in 12 normotensive endurance-trained and 12 hypertensive sedentary men using nonselective drugs with and without intrinsic sympathomimetic activity (ISA). Initially, subjects performed a graded treadmill test to determine maximal oxygen uptake (VO2max). This was followed by 2-hour walks at 25 and 45% of the subject's VO2max under each of 3 treatments: pindolol (ISA), propranolol (non-ISA) and placebo. The distribution of medication was randomized and double blinded. Blood samples taken at rest and every 30 minutes during the 2-hour walks were analyzed to determine the concentrations of free fatty acids (FFA) and glycerol. On the basis of the respective changes in FFA, glycerols and the respiratory exchange ratio, beta-adrenergic blockade did not attenuate lipolysis in the untrained hypertensive subjects when compared with the placebo administration. However, beta blockade did demonstrate a tendency to attenuate lipolysis in the trained, normotensive subjects when compared with results after placebo administration. This was particularly evident at 30 minutes of exercise, when both glycerol and FFA concentrations were not increased above resting values under both conditions of beta blockade. No differences between pindolol and propranolol were observed. Therefore, a beta-blocking agent with ISA properties appears to have no clear benefit with respect to lipid metabolism during low and moderate intensity exercise. Furthermore, these data demonstrate that beta blockade does not inhibit exercise-induced lipolysis at low and moderate intensities of exercise as formerly believed, and is unlikely to be the cause of fatigue normally observed during work in patient populations taking beta-blocking medication.
Tracheoesophageal anastomosis for intractable aspiration pneumonia. Permanent tracheostomy and tracheoesophageal anastomosis were performed as a means of surgical intervention for the treatment of intractable aspiration pneumonia. Conventional methods of tracheoesophageal anastomosis have entailed various problems. The improved method devised by us uses the special histological features and enables safe and reliable anastomosis. By this method, the tracheal perichondrium is retained and the strength of the anastomosed portion of the trachea is maintained, the failure of sutures due to tension on the anastomotic site being prevented. Also, reanastomosis can be performed after the cure of primary disease.
An epidemic outbreak of cryptosporidiosis: a prospective community study from Guinea Bissau. In the first year of a prospective community study of childhood diarrhea conducted in a semiurban area in the capital of Guinea Bissau, Cryptosporidium sp. was found in 73 (6.0%) of 1216 episodes of diarrhea. The parasite was the second most prevalent intestinal parasite, and the only one significantly associated with diarrhea (OR = 2.79, P = 0.0006). The seasonal distribution was striking, with a peak prevalence in the beginning of the rainy season (May 17.6%) when an epidemic outbreak of diarrhea started. The prevalence was highest in children younger than 18 months, an age at which prevalences of other intestinal parasites were low. This reverse age pattern may possibly be explained by the small infective dose needed to create severe infections, by air-borne transmission and by the development of protective immunity.
Magnetic resonance imaging of small hepatocellular carcinoma. Thirty-eight patients with small hepatocellular carcinomas (HCCs), size less than 20 mm, initially detected by ultrasound (US) and histologically confirmed, were examined by magnetic resonance (MR) imaging, computed tomographic (CT) scan, and angiography. MR imaging demonstrated HCC nodules in nine (75.0%) of 12 patients with tumors less than 10 mm in diameter and in 22 (84.6%) of 26 patients with tumors 10-20 mm in diameter. In total, HCC nodules were detected in 31 of 38 patients (81.6%) by MR imaging. On the other hand, HCC lesions were found on CT scan in 14 of 26 patients (53.8%) and in 27 of 35 patients (77.1%) by angiography. With MR imaging, HCC nodules were demonstrated in 21 of 31 patients on both T1 and T2 weighted images, and 13 of 21 patients (61.9%) were shown to have low intensity areas or iso intensity areas on T1 weighted image, whereas the other eight patients (38.1%) were shown to have high intensity areas. All 21 patients were shown to have high intensity areas on T2 weighted image. Among 15 resected cases, four patients had a high intensity area on T1 weighted image, and a significant fatty change was noted in HCC nodules by histological study of the resected specimen. We suggest that MR imaging is a useful diagnostic imaging modality, even in small HCC of less than 20 mm.
Expression of blood group antigens H-2, Le(y), and sialylated-Le(a) in human colorectal carcinoma. An immunohistochemical study using double-labeling techniques. In this study, double-labeling immunohistochemistry was used to gain insight into the coexpression or interrelationship between blood group antigens (BGA) that are differentiation antigens in the normal colon, and BGA that are sequential moieties in the same synthetic pathway. Paired-wise Sialylated-Le(a)/Le(y) and H-2/Le(y) was studied. The Sialylated-Le(a) and Le(y) are synthesized from type 1 and type 2 backbones, respectively. In the normal colon, the Le(y) and Sialylated-Le(a) are expressed by cells at the base and surface of the crypt, respectively, representing undifferentiated and differentiated enterocytes. The H-2 is considered oncofetal in nature, and is considered to be the immediate precursor in the synthesis of Le(y). In individual cancers. Sialylated-Lea and Le(y) were detected in different cancer cells within the same malignant glands, separately in different glands, and in different subcellular compartments of the same cell. Both H-2 and Le(y) were coexpressed in the same individual cells in 92% of cancers expressing both these BGA. In 50% of the cancers, the H-2 and Le(y) also were expressed separately in different malignant glands within individual tumors. These findings indicate that, in colorectal cancers, differentiation antigens (Sialylated Le(a) and Le(y)) are expressed by different individual cells within the same malignant gland somewhat, recapitulating the normal colon crypt. Antigens of different backbones occasionally may be expressed in the same cells but within different subcellular compartments. Precursor accumulation is common in cancers, and antigens in the same synthetic pathway are coexpressed in the same cell. The expression of H-2 and Le(y) in different glands (lack of coexpression) may be explained possibly by aberrant synthesis of Le(y) by an alternate pathway.
The glucose transporter and blood-brain barrier of human brain tumors. The glucose transporter of the human brain has been localized to endothelial cells expressing the blood-brain barrier, but little is known regarding its mechanism of induction or whether its expression is exclusively linked with restricted vascular permeability. We investigated glucose transporter expression by vessels in human astrocytic tumors and pulmonary metastases to the brain using immunohistochemical techniques. Vessels in 9 of 10 low-grade astrocytomas and 8 of 10 anaplastic astrocytomas were positive for glucose transporter. Glioblastoma vessels were transporter-positive in only 2 of 10 specimens. Vessels in all three metastatic tumors were negative for the glucose transporter. The decrease in transporter expression observed in higher-grade tumors occurred independently of increases in vascular permeability. In low-grade astrocytomas and glioblastomas transporter expression and contrast enhancement were inversely related, but vessels in 6 of 9 anaplastic astrocytomas were transporter-positive despite contrast enhancement. These findings suggest that separate mechanisms induce the glucose transporter and the permeability restrictions of the human blood-brain barrier. They also have potential implications for the therapy and prognosis of astroglial neoplasms.
Renal artery stenosis: evaluation with color Doppler flow imaging. Renal artery stenosis (RAS) is the most common correctable cause of hypertension. The current study was undertaken to evaluate the usefulness of color Doppler flow imaging as a screening examination in the detection of significant RAS. Fifty-five kidneys in 30 patients were examined with aortography and color Doppler flow imaging in a double-blind fashion. The peak systolic velocity (PSV) in the renal artery, the renal-aortic ratio (RAR) (ie, the ratio of the PSV in the renal artery to the PSV in the aorta), and the renal artery resistive index were determined and compared with the percentage of stenosis as determined with angiography. Ultrasound (US) criteria used to diagnose RAS were (a) an RAR of 3.5 or greater and/or (b) a renal artery PSV of greater than 100 cm/sec. Doppler tracings were obtained in 25 (69%) of 36 kidneys with a patent single renal artery. RAR and PSV each yielded a sensitivity of 0% in the diagnosis of RAS. Doppler tracings were obtained in three (50%) of six occluded renal arteries. Accessory arteries were present in 13 (24%) of 55 kidneys, but none were visualized with color Doppler flow imaging. The authors conclude that with current technical capability, color duplex US is not an adequate screening method for the detection of RAS.
Causes of failure after repeat vitreoretinal surgery for recurrent proliferative vitreoretinopathy. During the last two years, we performed vitreoretinal surgery on 37 eyes with retinal detachments and recurrent severe proliferative vitreoretinopathy in 37 patients who had had previous failed scleral buckling and vitreous surgery for proliferative vitreoretinopathy. Anterior proliferative vitreoretinopathy was present in 32 of 37 eyes (86%); posterior proliferative vitreoretinopathy of fixed retinal folds in four quadrants of narrow or closed funnel shape occurred in 23 of 37 eyes (62%); and subretinal proliferation was noted in 16 of 37 eyes (43%). The retinas in 12 eyes (32%) redetached from new or recurrent anterior proliferative vitreoretinopathy in nine eyes, reopening of pre-existing retinal breaks in two eyes, or recurrent posterior periretinal proliferation in one eye. With additional vitreoretinal procedures in six eyes and after a mean follow-up period of 11 months, 27 of 37 retinas (73%) were totally reattached, and an additional five eyes (13%) had retinal reattachment posterior to the scleral buckle. Of the 32 patients with posterior retinal reattachment, final visual acuity of 5/200 or better was attained in 19 eyes (59%).
Unilateral asterixis. We describe three patients with unilateral asterixis. One diabetic patient with a moderately-sized haematoma in the left putamen initially developed bilateral and symmetrical asterixis, which became confined to the right side as his diabetes mellitus was controlled. Two patients showed unilateral asterixis due to haematomas in the contralateral basal ganglia and thalamus, respectively. The present findings indicate that not only lesions of the thalamus but also those of the basal ganglia can cause unilateral asterixis, and bilateral and symmetrical asterixis does not necessarily exclude the presence of a focal mass lesion in the cerebrum.
Non-Hodgkins lymphoma of the head and neck: experience in the Grampian area. The records of 44 cases of non-Hodgkins lymphoma (NHL) presenting to the ear, nose and throat department in the Grampian area from 1980-1988 were examined in relation to site of occurrence, histology, age at presentation, clinical stage, treatment and survival. The median age was 67 years and there was a preponderance of high grade histology, especially in disease affecting the tonsil. Most deaths occurred in the first year; patients with high grade disease and those in stages three and four had a significantly poorer survival during the first year. The site of disease had no influence on survival.
Regional differences in the intranodal distribution of tumor cells. The intranodal distribution of tumor cells was examined in 103 mesenteric and 135 axillary nodes to determine the frequency of a circumferential type of distribution and its relationship, if any, to central necrosis. Eighteen percent of the mesenteric nodes removed at surgery from patients with colon cancer contained a circumferential rim of viable tumor cells in an area corresponding wholly or in part to the normal location of the marginal sinus. In each case this rim of tumor cells surrounded a large central area of necrosis. In contrast, only one of the 135 axillary nodes removed from patients with breast cancer demonstrated this pattern. These findings suggest that by interrupting blood and lymph vessels, the circumferential spread of tumor cells underlies development of central necrosis. Previously described structural dissimilarities between mesenteric and axillary nodes may explain the striking difference in incidence of this pattern in these nodes.
Phase I clinical and pharmacokinetic trial of flavone acetic acid. Flavone acetic acid is a synthetic benzopyrone derivative with an unknown mechanism of action. Thirty-eight patients (30 men and 8 women) were treated once a week for 4 weeks every 5 weeks with doses of flavone acetic acid ranging from 0.33 to 12.5 g/m2. At doses less than or equal to 3.9 g/m2, the drug was administered intravenously over 1 hour; at doses greater than or equal to 5.28 g/m2, the infusion period was lengthened to 6 hours. Treatment of all patients included hydration before and after treatment and alkalization to maintain urine pH at greater than or equal to 6.5. A dose-limiting toxic effect was hypotension at 10 g/m2. Pharmacokinetic studies revealed linear behavior in the eight patients studied, beginning at 3.9 g/m2. Peak plasma levels ranged from 125 to 630 micrograms/mL, with a mean terminal half-life of 22.4 hours. Immunologic monitoring was performed in three patients at 10 g/m2. A transient increase in CD16- and/or Leu-19-positive cells was noted in all three patients. In one patient, this increase correlated with a 10-fold increase in K562 cell killing. There were no objective tumor responses seen in this trial. The recommended phase II dose on this schedule is 8 g/m2. Further studies to elucidate the drug's mechanism of action and to define its immunologic properties are recommended.
Intraoperative radiation of canine carotid artery, internal jugular vein, and vagus nerve. Therapeutic applications in the management of advanced head and neck cancers. As a step in the application of intraoperative radiotherapy (IORT) for treating advanced head and neck cancers, preliminary information was obtained on the radiation tolerance of the canine common carotid artery, internal jugular vein, and vagus nerve to a single, high-dose electron beam. Both sides of the neck of eight mongrel dogs were operated on to expose an 8-cm segment of common carotid artery, internal jugular vein, and vagus nerve. One side of the neck was irradiated, using escalating doses of 2500, 3500, 4500, and 5500 cGy. The contralateral side of the neck served as the unirradiated control. At 3 and 6 months after IORT, one dog at each dose level was killed. None of the dogs developed carotid bleeding at any time after IORT. Light microscopic investigations using hematoxylin-eosin staining on the common carotid artery and internal jugular vein showed no consistent changes that suggested radiation damage; however, the Masson trichrome stain and hydroxyproline concentration of irradiated common carotid artery indicated an increase in the collagen content of the tunica media. Marked changes in the irradiated vagus nerve were seen, indicating severe demyelination and loss of nerve fibers, which appeared to be radiation-dose dependent. Four patients with advanced recurrent head and neck cancer were treated with surgical resection and IORT without any acute or subacute complications. The role of IORT as a supplement to surgery, external beam irradiation, and chemotherapy in selected patients with advanced head and neck cancer needs further exploration.
Osteosarcoma of the maxilla in Hong Kong Chinese postirradiation for nasopharyngeal carcinoma. A report of four cases. Postirradiation osteosarcoma of the maxilla was seen in four Hong Kong Chinese patients treated for nasopharyngeal carcinoma. These cases represent four of 42 (9%) cases of osteosarcoma at all sites in this institution during the period 1979 to 1989, when more than 1000 patients were treated with radiotherapy for nasopharyngeal carcinoma. The latent periods varied from 8 to 11 years from completion of radiotherapy treatment to development of osteosarcoma. The radiation dosage varied from 6000 to 6280 cGy in three of the patients. These cases fit the criteria for diagnosis of postirradiation sarcomas. Maxillary osteosarcomas after irradiation for nasopharyngeal carcinoma do not appear to have been described. The very high incidence of nasopharyngeal carcinoma (for which radiotherapy is the treatment of choice) in Hong Kong Chinese would make the occurrence of such tumors more likely in Hong Kong, although the small risk does not contraindicate the use of radiation in the treatment of nasopharyngeal carcinoma in view of its well-documented efficacy.
Mutation of the p53 gene in human acute myelogenous leukemia. Heterogeneity of p53 protein expression is seen in blast cells of patients with acute myelogenous leukemia (AML). p53 protein is detected in the blasts of certain AML patients but not in others. We have identified p53 protein variants with abnormal mobility on gel electrophoresis and/or prolonged half-life (t 1/2). We have sequenced the p53 coding sequence from primary blast cells of five AML patients and from the AML cell line (OCIM2). In OCIM2, a point mutation in codon 274 was identified that changes a valine residue to aspartic acid. A wild type p53 allele was not detected in these cells. Two point mutations (codon 135, cysteine to serine; codon 246, methionine to valine) were identified in cDNA from blasts of one AML patient. Both mutations were present in blast colonies grown from single blast progenitor cells, indicating that individual leukemia cells had sustained mutation of both p53 alleles. The cDNAs sequenced from blast samples of four other patients, including one with prolonged p53 protein t 1/2 and one with no detectable p53 protein, were fully wild type. Thus, the heterogeneity of p53 expression cannot be explained in all cases by genetic change in the p53 coding sequence. The prolonged t 1/2 of p53 protein seen in some AML blasts may therefore reflect changes not inherent to p53. A model is proposed in which mutational inactivation of p53, although not required for the evolution of neoplasia, would confer a selective advantage, favoring clonal outgrowth during disease progression.
The utility of echocardiography in the diagnostic strategy of postinfarction ventricular septal rupture: a comparison of two-dimensional echocardiography versus Doppler color flow imaging. The diagnostic accuracy of Doppler color flow imaging in the diagnosis of postinfarction ventricular septal defects has not been established. In this study, 43 patients with unexplained hypotension or a new murmur in the periinfarct period were evaluated with conventional two-dimensional echocardiography and Doppler color flow imaging. The presence of a ventricular septal defect was confirmed by oximetry, ventriculography, operative repair, or autopsy in each case. Both two-dimensional and Doppler color flow imaging were 100% specific in excluding a ventricular septal defect. Doppler color flow imaging correctly identified the 12 confirmed ventricular septal defects in this study (100% sensitivity), whereas any combination of two-dimensional criteria only correctly identified seven (58% sensitive) (p less than 0.05). Doppler color flow imaging is superior to conventional two-dimensional imaging in the diagnosis of a postinfarction ventricular septal defect. In addition, Doppler color flow imaging localized the septal defect, and thus guided therapy and technique for repair. Carefully performed Doppler color flow examination can exclude or result in the rapid diagnosis of a ventricular septal defect, which eliminates the need for further time-consuming confirmatory testing.