123rc/medical_text huggingface dataset:
Effect of hypoxia on cerebral metabolites measured by proton nuclear magnetic resonance spectroscopy in rats. Proton nuclear magnetic resonance spectroscopy is a unique method to monitor noninvasively the concentrations of cerebral metabolites. N-Acetyl-L-aspartate, the concentration of which is assumed to be stable during hypoxia, has been used to form ratios with lactate. To determine the stability of the signal from N-acetyl-L-aspartate, we used a model of graded hypoxia in rats to monitor the percentage changes from baseline of the peak heights for lactate, lipids, and N-acetyl-L-aspartate. Anesthetized adult rats were exposed sequentially to 15% and 10% O2 while proton nuclear magnetic resonance spectra were collected with a surface coil in a 7-T 89-mm-bore spectrometer. Brain lactate concentration was either increased by feeding or infusion of glucose (n = 9) or lowered by fasting (n = 7). After death the brains were removed and frozen, and the water- and lipid-soluble compounds were extracted to identify the origin of the signals. We analyzed the data both as the percentage change from baseline for heights of the lactate (1.33 ppm), lipids (1.5 ppm), and N-acetyl-L-aspartate (2.02 ppm) peaks and as the ratios of heights of the 1.33 and 2.02 and the 1.5 and 2.02 ppm peaks. Both hypoxic episodes caused a 45% decrease from baseline in the 2.02 ppm peak. During the second hypoxic episode, the 1.33:2.02 ppm peak height ratio increased significantly in hyperglycemic rats (p less than 0.05) but was unchanged in hypoglycemic rats.
Rupture of atheromatous plaque as a cause of thrombotic occlusion of stenotic internal carotid artery. We analyzed the clinical profiles and autopsy findings of five patients who died shortly after developing cerebral infarction following thrombotic occlusion of the internal carotid artery. In all five cases, thrombotic occlusion was caused by rupture of the fibrous lining over the gruel of atheroma at the origin of the internal carotid artery showing tight stenosis of the lumen. The mean +/- SD shorter diameter of the lumen at the site of occlusion was 1.5 +/- 0.4 mm. Our results show that an internal carotid artery with tight stenosis of the lumen by atheroma containing gruel harbors a risk of thrombotic occlusion, which may give rise to cerebral infarction by artery-to-artery embolism or by reduced cerebral perfusion.
Portacaval shunt versus endoscopic sclerotherapy in the elective treatment of variceal hemorrhage. Eighty-two consecutive Child-Campbell class A and B cirrhotic patients were included in a prospective controlled trial to assess the efficacy and safety of portacaval anastomosis vs. endoscopic sclerotherapy as elective treatment of variceal hemorrhage. Forty-one patients were randomized to portacaval anastomosis and 41 to sclerotherapy. After excluding dropouts, 34 patients were treated with portacaval anastomosis and 35 with sclerotherapy. The incidence of variceal rebleeding during follow-up (mean +/- SD, 20.6 +/- 14.2 months) was significantly higher in the sclerotherapy than in the portacaval groups, either considering the overall treated group or only patients completing sclerotherapy (40% and 25% vs. 2.9%; P = 0.0002 and P = 0.01, respectively). The 2-year probability of suffering from at least one episode of hepatic encephalopathy was significantly higher in patients submitted to portacaval anastomosis than in those treated with endoscopic sclerotherapy (40% vs. 12%; P = 0.04). However, disabling encephalopathy only appeared in 3 of 34 patients who underwent surgery (8.8%). Early and long-term mortality did not differ between the therapeutic groups; 2-year survival rates were 83% for portacaval anastomosis and 79% for sclerotherapy. It is concluded that portacaval anastomosis is more effective than endoscopic sclerotherapy in preventing variceal rebleeding in spite of the greater incidence of hepatic encephalopathy. The role of portacaval anastomosis in the elective treatment of variceal rebleeding should be reassessed.
Extracorporeal shock wave lithotripsy in combination with transurethral surgery for management of large bladder calculi and moderate outlet obstruction. In 5 men evaluated for symptoms of obstructive voiding flexible cystoscopy revealed large or multiple bladder calculi along with small to moderate prostatic enlargement. All patients had successful localization and fragmentation of calculi with the Dornier HM3 lithotriptor. Of these patients 4 underwent transurethral resection or incision of the prostate under the same epidural anesthesia for moderate prostatic obstruction without complication and 1 subsequently required suprapubic prostatectomy of a gland with a large middle lobe that made a transurethral operation difficult. Extracorporeal shock wave lithotripsy should be considered for the primary management of large or hard bladder calculi and it is of particular value in combination with a transurethral operation for patients with small to moderate prostatic obstruction.
Vitamin C and cancer prevention: the epidemiologic evidence. Epidemiologic evidence of a protective effect of vitamin C for non-hormone-dependent cancers is strong. Of the 46 such studies in which a dietary vitamin C index was calculated, 33 found statistically significant protection, with high intake conferring approximately a twofold protective effect compared with low intake. Of 29 additional studies that assessed fruit intake, 21 found significant protection. For cancers of the esophagus, larynx, oral cavity, and pancreas, evidence for a protective effect of vitamin C or some component in fruit is strong and consistent. For cancers of the stomach, rectum, breast, and cervix there is also strong evidence. Several recent lung cancer studies found significant protective effects of vitamin C or of foods that are better sources of vitamin C than of beta-carotene. It is likely that ascorbic acid, carotenoids, and other factors in fruits and vegetables act jointly. Increased consumption of fruits and vegetables in general should be encouraged.
Intraoperative transesophageal color-coded Doppler echocardiography for evaluation of residual regurgitation after mitral valve repair. Because mitral valve competence after mitral valve reconstruction is awkward to assess during this procedure, we evaluated in this respect transesophageal color-coded Doppler echocardiography in 23 patients undergoing mitral valve reconstruction for severe mitral regurgitation. Transesophageal echocardiographic examinations were performed after induction of anesthesia but before sternotomy (baseline), after mitral valve repair before decannulation, and at sternal closure, all at similar mean aortic pressure and echocardiographic instrument settings. The degree of mitral regurgitation by transesophageal color Doppler flow mapping was visually quantified on a 5-point scale (0 to 4), pending the left atrial extent of the regurgitant jet. This was compared with the degree of mitral regurgitation by left ventricular cineangiography performed within several weeks after operation and also visually quantified on a 5-point scale (0 to 4), with use of the right anterior oblique projection. There was good correlation between the two methods (r = 0.83; p less than 0.001). We conclude that residual mitral regurgitation, as assessed by transesophageal color flow mapping in the operating room, highly correlates with the ultimate mitral regurgitation by cineangiography. Therefore transesophageal echocardiography can be helpful for evaluation of mitral valve competence during mitral valve reconstruction, and hence, in case of repair failure, allow valve replacement in the same surgical session, thus avoiding reoperation.
A simple and sensitive microtiter plate estrogen bioassay based on stimulation of alkaline phosphatase in Ishikawa cells: estrogenic action of delta 5 adrenal steroids. We have developed an estrogen bioassay using the Ishikawa human endometrial adenocarcinoma cell line growing in 96-well microtiter plates. Alkaline phosphatase enzyme activity (AlkP) in these cells is markedly stimulated by estrogens, and this enzyme can be easily quantified in situ using a chromogenic substrate. These cells are very sensitive to estrogens; estradiol induces AlkP at levels as low as 10(-12) M. Antiestrogens completely block the action of estradiol. Various estrogens stimulate AlkP with potencies comparable to those achieved in vivo. The induction of AlkP is specific for estrogens; no other type of steroid, including androgens, progestins, mineralocorticoids, or glucocorticoids produce this effect. The stimulation of AlkP in Ishikawa cells is specific for estrogens, is highly reproducible and sensitive, and permits large numbers of samples to be assayed with ease. We have used this assay to investigate the estrogenic action of the adrenal delta 5-3 beta-hydroxysteroids. While pregnenolone is inactive, dehydroepiandrosterone and its sulfate ester induce AlkP slightly. However, the C19 steroid, 5-androstene-3 beta, 17 beta-diol is considerably more estrogenic in this assay, although it stimulates Ishikawa AlkP with a potency of 1/30,000 that of estradiol. The stimulation by 5-androstene-3 beta,17 beta-diol is inhibited by antiestrogens, but it is not blocked by the delta 5-3 beta-hydroxysteroid isomerase/dehydrogenase inhibitor, cyanoketone, or by the aromatase inhibitor, 4-hydroxy-androstenedione. Thus, neither conversion to a delta 4-3-ketone nor aromatization is required for the action of this unusual estrogen.
Clinical nuclear magnetic resonance spectroscopy: insight into metabolism. Nuclear magnetic resonance (NMR) spectroscopy can nondestructively evaluate changes in metabolites with different disease states, as well as with therapeutic interventions. Animal studies have provided the basis for understanding changes in high-energy phosphates with myocardial ischemia. Studies of graded ischemia due to partial coronary stenosis have shown the sensitivity of the ratio of phosphocreatinine to inorganic phosphate to small reductions in myocardial blood flow and its relation to myocardial function. The application of NMR spectroscopy to humans requires precise localization techniques to avoid acquiring contaminating information from structures around the heart, such as the chest wall and diaphragm. With these localization techniques, metabolic evidence of ischemia has been demonstrated in patients with myocardial infarction and patients with known coronary disease, although the sensitivity of this technique for the diagnosis of inducible ischemia is unknown. At rest, patients with dilated and hypertrophic cardiomyopathies often have an elevated phosphodiester resonance, possibly signifying abnormal breakdown of membrane phospholipids. Increasing oxygen demand in these patients does not usually alter high-energy phosphates, suggesting that oxidative energy metabolism is preserved under these conditions. NMR spectroscopy is a powerful tool to increase understanding of metabolic changes in a variety of pathologic conditions.
Flow cytometric evaluation of chemosensitive and chemoresistant head and neck tumors. For patients with head and neck squamous carcinoma, a clinical response to induction chemotherapy has correlated with a survival advantage. Similarly, patients with diploid tumors have displayed a survival advantage when compared with patients with aneuploid tumors. This study examined DNA content in 33 patients who had undergone induction chemotherapy as part of two clinical protocols to determine if there was a correlation between the patients with diploid tumors and the patients with a clinical response to chemotherapy. Although patients with stage III tumors had a longer disease-free survival than stage IV patients (p less than 0.0002), the addition of DNA content information did not improve the ability to predict response. Specifically, there was no correlation between DNA content and the response to chemotherapy. In addition, for this group of patients, a diploid DNA content was not correlated with a survival advantage. We conclude that DNA content information did not add significantly to the prediction of clinical outcome in these patients who received induction chemotherapy.
Anterior segment ischemia: a complication of retinal detachment repair in a patient with sickle cell trait. Anterior segment ischemia (ASI) is a dreaded complication of retinal detachment surgery particularly in patients with predisposing factors such as sickle cell disease. We report a case of ASI after scleral buckling in an otherwise healthy black patient with sickle cell trait. Conditions of relative hypoxia intraoperatively from either anesthesia or surgical manipulation may precipitate vasoocclusive phenomena in these normally asymptomatic patients. Since the incidence of sickle cell trait in the black population in the United States is 8.5%, we recommend these patients have a preoperative sickle test followed by hemoglobin electrophoresis with quantification if positive. The presence of sickle cell trait should alert the surgeon to the risk of ASI, and factors predisposing to hypoxia should be minimized when possible.
Transesophageal echocardiography during percutaneous balloon mitral valvuloplasty. To ascertain the value of transesophageal echocardiography during percutaneous balloon mitral valvuloplasty, the present study was undertaken in 26 anesthesized patients (21 women and 5 men; mean age, 47 years) with symptomatic rheumatic mitral valve stenosis. In all but one patient the balloon dilation of the mitral valve was successful and Doppler-derived valve area increased (0.9 +/- 0.3 to 1.9 +/- 0.4 cm2). Transesophageal echocardiography provides continuous monitoring, as well as guidance of the procedure. Crossing the arterial septum, as well as delivery of the sheath through the mitral valve orifice and correct positioning of the balloon, was highly facilitated and reduced x-ray exposure time. The degree of mitral regurgitation and the presence of interatrial shunting at the end of the procedure could be readily assessed, making cineangiography not necessary. Complications of the procedure, such as pericardial effusion, could be detected before hemodynamic deterioration had occurred (one patient). The advantages of transesophageal echocardiography for routine monitoring of percutaneous mitral valvuloplasty, however, should be weighted against the added risk and expense of this support.
Chronic posterior subluxation and dislocation of the radial head. The clinical and radiographic features of chronic posterior subluxation or dislocation of the radial head were studied in thirty-four elbows of twenty-seven patients. Three characteristic radiographic types were noted: Type I, subluxation; Type II, posterior dislocation with minimum displacement; and Type III, posterior dislocation with substantial proximal migration of the radius. Follow-up of eighteen patients (twenty-one elbows) revealed that posterior displacement did not usually cause serious functional impairment except for loss of rotation of the forearm. The least common presentation, Type-I subluxation, caused pain and clicking and was associated with late degenerative arthritis. Cosmetic deformity due to prominence of the radial head was also a cosmetic problem, particularly with Type-III dislocation.
Human basophils express interleukin-4 receptors. Interleukin-4 (IL-4), a multipotential lymphokine reputed to play an important role in the regulation of immune responses, interacts with a variety of hemopoietic target cells through specific cell surface membrane receptors. The present study was designed to investigate whether human basophils express IL-4 binding sites. For this purpose, basophils were enriched to homogeneity (93% and 98% purity, respectively) from the peripheral blood of two chronic granulocytic leukemia (CGL) donors using a cocktail of monoclonal antibodies (MoAbs) and complement. Purified basophils bound 125I-radiolabeled recombinant human (rh) IL-4 in a specific manner. Quantitative binding studies and Scatchard plot analysis revealed the presence of a single class of high affinity IL-4 binding sites (280 +/- 40 sites per cell in donor 1 and 640 +/- 45 sites per cell in donor 2) with an apparent dissociation constant, kd, of 7.12 x 10(-11) +/- 2.29 x 10(-11) and 9.55 +/- 3.5 x 10(-11) mol/L, respectively. KU812-F, a human basophil precursor cell line, was found to express a single class of 810 to 1,500 high affinity IL-4 binding sites with a kd of 2.63 to 5.54 x 10(-10) mol/L. No change in the numbers or binding constants of IL-4 receptors was found after exposure of KU812-F cells to rhIL-3 (a potent activator of basophils) for 60 minutes. No effect of rhIL-4 on 3H-thymidine uptake, release or synthesis of histamine, or expression of basophil differentiation antigens (Bsp-1, CD11b, CD25, CD40, CD54) on primary human CGL basophils or KU812-F cells was observed.
Comparison of pump-driven and spontaneous continuous haemofiltration in postoperative acute renal failure. In a comparison of spontaneous continuous arteriovenous haemofiltration (CAVH) and pump-driven haemofiltration (PDHF) for acute renal failure after surgery, 116 patients admitted to a surgical intensive care unit were assigned CAVH (48) or PDHF (68). The method of assignment was that a patient was treated by PDHF if he or she was the only patient requiring treatment at that time (only one pump was available); any other patient coming to the unit would be treated by CAVH. The groups were slightly unbalanced because there were fewer simultaneous cases than expected. The main endpoints were survival rate, control of uraemia, and additional application of haemodialysis. There were no differences between the patient groups in age, duration of treatment, severity of illness, serum creatinine concentration at the start of treatment, or cause of acute renal failure. Both treatments adequately controlled uraemia and fluid overload. However, the survival rate was significantly higher with PDHF than with CAVH (6 [12.5%] vs 20 [29.4%]; p less than 0.05). The daily ultrafiltrate volume was significantly higher with PDHF than with CAVH (15.7 [95% confidence interval 13.6-17.8] vs 7.0 [6.6-7.4] l/day; p less than 0.05). The volume of ultrafiltrate in patients with ischaemic or sepsis-induced acute renal failure was correlated with the survival rate. This finding suggests that the better survival rate in the PDHF group was due to faster elimination of toxic mediators (of molecular weight 800-1000 daltons) through the filter membrane by high-volume haemofiltration.
Colorectal cancer: differences between community and geographically distant patients seen at an urban medical center. Many studies in clinical oncology rely on hospital-derived patients. Hospitals vary in the proportions of patients from the local catchment area vs. those from more distant places, of whom a larger proportion are presumably referrals. To study the differences between these two types of patients, we analyzed 1,245 colorectal cancer patients seen at a large urban medical center over a seven-year period. Three hundred ninety-eight patients were from the local community (32 percent), 489 were from the extended community (39.3 percent), and 358 from more distant communities (28.8 percent). The patients from the local community tended to be older and from minority ethnic groups. In addition, the local community patients were more likely to have advanced disease at the time of presentation. The grade of the tumor and its site distribution within the large bowel were similar for the three groups. After adjusting for age, sex, race, and stage of disease, the survival was somewhat better for the distant community patients as compared with the local and extended communities (P less than 0.02). Overall, in our patient population, the distant patients tended to have more favorable socioeconomic factors and less advanced disease, and these differences may account, in large part, for a better prognosis for these patients. Particularly in large cooperative trials, studies may need to take into account the respective proportions of local community and geographically distant patients in analyzing and generalizing treatment outcomes.
Cyclosporin-associated akinetic mutism and extrapyramidal syndrome after liver transplantation. Three patients developed akinetic mutism on the third day after the introduction of intravenous cyclosporin A, given for immunosuppression after liver transplantation. One patient in addition developed a florid orofacial dyskinesia, which resolved completely, as did the akinetic mutism, after withdrawal of cyclosporin. In these patients the time course of the akinetic mutism and extrapyramidal syndrome, which developed in the absence of any other identifiable cause, suggests cyclosporin A was the precipitating factor. Subsequently, two of the patients showed signs of pseudobulbar palsy with abnormalities in the pons on MRI scanning, suggesting central pontine myelinolysis (CPM). None of the patients had experienced significant fluctuations in serum sodium or other risk factors for central pontine myelinolysis and the exact relationship to the earlier cyclosporin related mutism was not clear.
The mutation for medullary thyroid carcinoma with parathyroid tumors (MTC with PTs) is closely linked to the centromeric region of chromosome 10. Two new morphs (F and G) detected by the centromeric alpha satellite probe p alpha 10RP8 and D10Z1 in HinfI digests are linked to the PstI polymorphisms of D10Z1, confirming their chromosome 10 location. The F and G morphs were in strong linkage disequilibrium with each other but were in weak linkage disequilibrium with the A and B morphs defined in PstI digests. Data for haplotypes formed by using the A and F morphs improved the lod score for linkage between the disease locus for multiple endocrine neoplasia type 2A (MEN2A) and D10Z1 (Z = 14.06 at theta = 0) in the six large families studied by Wu et al. Furthermore, the locus that codes for a distinct phenotype, medullary thyroid carcinoma (MTC) with parathyroid tumors (PTs) and no pheochromocytomas (PHEOs) (referred to as MTC with PTs), in one of the families was closely linked to two markers, D10Z1 and RBP3, with lodscores of 2.86 and 3.54, respectively, at theta = 0. A possible allelic association was noted between disease phenotypes and centromeric haplotypes. The phenotype MTC and PHEOs with and without PTs was associated with the same relatively common centromeric haplotype (A + B-F-G-) in the four families in which all four morphs could be determined, while the phenotype MTC with PTs was associated with the rare centromeric haplotype (A-B-F-G+) in one family.
Exposure of the intracavernous carotid artery in aneurysm surgery. The pterional intradural approach was used in five cases of large and giant carotid-ophthalmic aneurysms and in two cases of intracavernous aneurysms that arose from the anterior siphon knee in the cavernous sinus (CS) and extended into the carotid cistern. In four cases of large carotid-ophthalmic aneurysms removal of the anterior clinoid process and the roof of the optic canal gave easy access to the pericarotid ring. The anteromedial part of the pericarotid ring was dissected to expose the extradural portion of the internal carotid artery (ICA) proximal to the neck and to make enough room between the wall of the CS and the extradural portion of the ICA, thus allowing easy clipping of the neck. In one case of a giant carotid-ophthalmic aneurysm extending into the CS with an extradural origin of the ophthalmic artery and in two cases of an intracavernous aneurysm arising from the siphon knee, neck clipping was performed by opening the lateral wall and roof of the CS after removal of the optic strut. The opening of the lateral wall anterior to the 3rd nerve facilitated wide exposure of the anterior siphon knee. The horizontal portion of the intracavernous ICA as well as the whole aspect of the aneurysm could be exposed as a result of the extended opening of the cavernous roof anterior to the posterior clinoid process. Successful operative results were obtained in all seven patients. A visual field detect as an operative complication was noted in one patient. No disturbance of ocular movements was noted.