123rc/medical_text huggingface dataset:
Biliary endoprostheses. Plastic versus metal stents. Plastic biliary endoprostheses relieved malignant obstructive jaundice in 80% to 90% of the patients. The comfort of a completely indwelling endoprosthesis should be offered to all palliatively treated tumor patients, and external-internal catheters should be reserved for the minority of patients who return with reoccluded endoprostheses. These patients have bacterial flora that rapidly contaminates the endoprosthesis and causes encrustations and reocclusions. Thus, a second endoprosthesis also would reocclude quickly. The mechanism of reocclusion of plastic and metal endoprostheses is completely different. In plastic endoprostheses, bacterial contamination causes decomposition of the bile and subsequent encrustation. In metal endoprostheses tumor ingrowths between the struts of the stent cause reocclusion. Tumor ingrowths were observed in only 6.5% of metal prostheses with a narrow woven mesh (Wallstent), whereas prostheses with large distances between the struts (Gianturco stent) had ingrowth rates of 19% to 50%. This fact shows that tumor ingrowths can be reduced by narrowing the spaces between the metallic network, and, therefore, improvements in the design of the metal stents should reduce the occlusion rate to or below that of plastic endoprostheses, which currently have a lower encrustation rate. The major advantages of expandable metal prostheses are the relative ease and the minimal trauma of the implantation procedure. The Wallstent endoprosthesis, in particular, can be inserted through a 7-F introducer sheath and offers the chance of single-step placement. The 30-day mortality rate, therefore, was only 5%. This is significantly lower than the 30-day mortality rate after insertion of plastic prostheses (15% to 24%). Even simple external catheter drainage procedures have a higher reported 30-day mortality rate (27%). Expandable metal endoprostheses would be the most useful device if the occlusion rate could be kept under 10% in large series. Increasing the length of the endoprostheses to 10 cm in the expanded state could also improve the long-term patency rates.
Susceptibility to thyroid autoimmune disease: molecular analysis of HLA-D region genes identifies new markers for goitrous Hashimoto's thyroiditis. Hashimoto's thyroiditis has been shown to be associated with the HLA-specificities DR4 and DR5. Since former association studies yielded variable results, we used novel molecular typing methods to assess predisposing immunogenetic factors. Gene analysis of the HLA-DR-DQ and tumor necrosis factor region was performed in a group of Hashimoto's thyroiditis patients and randomly chosen controls using standards and nomenclature of the 10th International Histocompatibility Workshop. Genomic DNA of patients and controls was analyzed using a cDNA probe of the DQB1 gene. The resulting restriction fragment patterns allowed the determination of newly defined DQw-types 1-9. We find the strongest relative risk conferred by DQw7 (RR = 4.7), that is observed in 36 of 64 patients (56%) and only 21 of 98 controls (21%) (P corr less than 0.002). Comparison of DNA sequence variation in the DQB1 gene, that is found predominantly in Hashimoto's thyroiditis patients, indicates that codons 45 and 57 are critical features in DQw7 which distinguish it from other DQw specificities. The adjacent DQA1 genes also display a significant association with Hashimoto's thyroiditis (DQA1*0201/*0301 heterozygotes were found in 37% of patients and 15% controls, P less than 0.03). No significant association could be found with polymorphisms of the tumor necrosis factor gene. These results provide a new basis for the concept of genetic susceptibility in Hashimoto's thyroiditis and will help to elucidate the underlying autoimmune mechanisms that lead to disease at the functional level.
Nutritional approach to cancer prevention with emphasis on vitamins, antioxidants, and carotenoids. The main human cancers are associated with complex life-style related causative, enhancing, and inhibiting factors. Tobacco smoking or chewing exposes humans to genotoxic carcinogens and to promoting substances. Likewise, Western dietary traditions involve certain carcinogens and promoters, whereas Oriental traditions implicate other carcinogens and promoters. Importantly, in virtually all situations regular intake of fruits and vegetables appreciably lowers the risk of cancer. This paper reviews the causes of the main human cancers and analyzes the mechanisms of the protective effects of fruits and vegetables. Prevention of human cancer requires the definition of optimal levels of recommended daily allowances of micronutrients.
Relationship between histologic features, DNA flow cytometry, and clinical behavior of squamous cell carcinomas of the larynx. Flow cytometric analysis of DNA content was done on 133 primary squamous cell carcinomas of the larynx. Overall, 76 tumors (57.1%) were not diploid (aneuploid or tetraploid). The DNA index (DI) was calculated and grouped into three levels. Fifty-seven cases had a DI in a range of 1.85 to 2.15 (44 diploid and 13 tetraploid). The cases were grouped in relation to ploidy, proliferative index, and the tumor-node-metastasis (TNM) system. Every group was analyzed with respect to survival rate. Ploidy was related to histocytologic grade. In well-differentiated tumors (G1) survival rates at 48 months were 41.7% in diploid cases and 27.7% in nondiploid ones (relative risk [RR], 2.01; 95% confidence interval [CI], 0.89, 4.52). In NO cases that underwent surgery, survival rates at 48 months were, respectively, 81.8% and 49.2% (RR, 5.07; 95% CI, 0.76, 33.93). These results suggest that ploidy may be a new independent parameter of prognosis in squamous cell carcinoma of the larynx. This is useful in clinical practice because it allows the clinician to recognize those cases with poorer prognosis among the early tumors at a stage where other prognostic parameters are not yet available.
Fasting in vivo delays myocardial cell damage after brief periods of ischemia in the isolated working rat heart. To assess the effects of fasting on recovery of function and exogenous glucose metabolism after 15 minutes of total ischemia, we perfused isolated working rat hearts from fed and fasted animals. Hearts were perfused in a recirculating system with bicarbonate buffer containing glucose (10 mM). Mechanical performance, release of marker proteins for ischemic membrane damage (lactate dehydrogenase, myoglobin, citrate synthase), and the concentrations of lactate and glucose in the perfusion medium were measured serially. Tissue metabolites were also measured. Fasting raised the myocardial glycogen content by 25%. Cardiac performance of perfused hearts from fed and fasted animals was the same during the preischemic and the post-ischemic period. The time of return of function to preischemic values was significantly less in hearts from fasted rats (2.3 versus 7.8 minutes, p less than 0.025). The release of cytosolic and mitochondrial marker proteins was significantly lower in hearts from fasted rats than in hearts from fed rats. Glucose metabolic rates during control and reperfusion were unchanged for hearts from fasted rats, but decreased for hearts from fed rats during reperfusion. The adenine nucleotide content at the end of ischemia was higher in hearts from fasted animals than in hearts from fed animals. We conclude that increasing glycogen levels prior to ischemia improves recovery of function, lessens membrane damage, and prevents loss of adenine nucleotides.
Coexpression of two fibronectin receptors, VLA-4 and VLA-5, by immature human erythroblastic precursor cells. Human erythroblastic precursor cells adhere to fibronectin (Fn) but the exact nature of the receptors mediating this interaction has not been characterized. In this study, we report data showing that immature human erythroblasts express the integrins VLA-4 and VLA-5 and that both these molecules act as fibronectin receptors on these cells. We have recently demonstrated that adhesion to Fn of purified human CFU-E and their immediate progeny preproerythroblasts was inhibited by antibodies directed against the human fibronectin receptor (VLA-5). Here we have extended those results and characterized by immunoprecipitation with specific antibodies the integrins expressed on surface-labeled normal human immature erythroblasts. A polyclonal antibody recognizing the common VLA beta 1 subunit yielded two polypeptides of 120 and 160 kD. Our data further demonstrate that the polypeptide of 160 kD contains alpha subunits corresponding to both alpha 4 and alpha 5. Thus, erythroblast lysates prepared in 0.3% CHAPS and immunoprecipitated with antibodies which specifically recognize the alpha 4 subunit showed a heterodimer with peptides of 120 (beta 1) and 160 kD (alpha 4) and the additional peptides of 70 and 80 kD which usually coprecipitate with the alpha 4 chain. On the other hand, specific anti-alpha 5 antibodies immunoprecipitated an alpha 5/beta 1 complex with peptides of 120 and 160 kD which under reducing conditions migrated as a single band of 130 kD. Similar experiments performed with an erythroleukemic cell line (KU 812) showed that these cells also coexpress both the VLA-4 and VLA-5 members of the integrin family. Furthermore, monoclonal antibodies recognizing the VLA alpha 4 chain blocked the adhesion of immature erythroblasts to Fn-coated surfaces, thus demonstrating that, as VLA-5, VLA-4 is also a functional Fn receptor on these cells.
Timing of osteosynthesis of major fractures in patients with severe brain injury. A retrospective study was performed to assess the effects on outcome of early osteosynthesis of major extremity fractures in patients with severe brain injury (GCS less than or equal to 7). In a consecutive series of 58 patients, early osteosynthesis was performed on the day of injury in 15 patients. (Group A). In 43 patients no major fractures were present or no early osteosynthesis was performed (Group B). The severity of brain injury as seen on CT scan was similar in both groups. Mortality was significantly lower in Group A, despite a significantly higher ISS. As to the functional end result of brain injury, an indication of a better outcome was present in Group A.
Immunologic aspects of carbamazepine treatment in epileptic patients. Immune abnormalities have been found in epileptic patients receiving antiepileptic drugs (AEDs). Phenytoin (PHT) produces a decrease in serum IgA and IgM levels and a decrease in blastic transformation of circulating lymphocytes stimulated with phytohemoagglutinin (PHA). The effects of carbamazepine (CBZ) on the immune response are still conflicting. To elucidate the effects of CBZ on some immunologic parameters, serum concentrations of IgA, IgG, IgM, the phagocytosis and killing properties of polymorphonuclear leukocytes (PMNs), the cytotoxic activity of natural killer cells and the response of lymphocytes to mitogenic agents were studied. Forty healthy individuals and 39 epileptic patients treated with carbamazepine (CBZ) monotherapy (age range 18-40 years) entered the study. Student's t test was used to evaluate the data. CBZ had no effect on the serum immunoglobulin concentrations or on lymphocytic reactivity to phytohemoagglutinin (PHA) mitogen. CBZ produced a significant enhancement of phagocytosis and killing properties of PMNs and an increase in natural killer (NK) cell activity. Therefore, a negative effect of CBZ therapy on the immune system was not observed in this study.
The pitted duodenal bulb. The radiologic, endoscopic, and histologic findings in two patients with flaskshaped or collar-button collections of barium in the duodenum are presented. These abnormal mucosal depressions, which may be related to inflammation, were seen endoscopically and identified radiographically and have not been reported previously.
Value of plasmapheresis in hepatic encephalopathy. Plasmapheresis is used for treating the complications of liver failure. We performed plasmapheresis on 6 children with hepatic encephalopathy resulting from acute hepatic failure and prospectively assessed its effects on neurologic and electrophysiologic (electroencephalography and evoked potentials) function. Clinical improvement was observed in 3 of 6 patients; changes in the serum ammonia value or the results of initial electrophysiologic tests did not predict the patient response. Two patients underwent transplantation after neurologic improvement was produced by plasmapheresis; however, despite plasmapheresis, 4 patients progressed to brain death. Our data demonstrate that plasmapheresis may transiently improve the encephalopathy of acute hepatic failure but is not curative alone. Therefore, plasmapheresis may be a useful adjunct in the treatment of liver failure, potentially improving the pretransplantation status of the patient.
The effects of dopamine on myocardial functional recovery after reversible ischemic injury. Dopamine frequently is used to improve cardiac performance after acute myocardial ischemia. Inotropic agents, however, increase myocardial oxygen demand and could potentially delay recovery from ischemic injury. To evaluate this problem, we studied eight chronically instrumented dogs in the conscious state and performed two 15-minute coronary occlusions 48 hours apart. After one of the occlusions, either dopamine (15 micrograms/kg/min) or saline placebo was administered intravenously from 1.0 to 1.5 hours of reperfusion. The alternative infusion was given during the second study. Preload recruitable work area, the area beneath the stroke work versus end-diastolic length relationship, was used to assess intrinsic myocardial performance. Ischemia decreased preload recruitable work area to 13% of control after both occlusions. After reperfusion, a 30-minute dopamine infusion acutely increased myocardial function nearly threefold as compared with placebo. Myocardial performance after dopamine administration, however, was significantly depressed compared with placebo throughout the remaining 24 hours of reperfusion (p less than 0.01). These data indicate that dopamine may impair functional recovery after ischemic myocardial injury and suggest that inotropic interventions should be used in this setting only when absolutely indicated.
Hemodynamic effects of diltiazem during vasoconstrictor pulmonary hypertension in sheep. Calcium channel blockers have been effective as pulmonary vasodilators in patients with pulmonary hypertension. The current study therefore compared the effects of prostaglandin E1, an effective pulmonary vasodilator, with the effects of the water-soluble calcium channel blocker diltiazem during pulmonary hypertension in sheep. Pulmonary hypertension was produced by continuous intravenous administration of U46619 to halothane-anesthetized sheep. Prostaglandin E1 decreased pulmonary artery pressure 29%, decreased pulmonary vascular resistance (Rp) 57%, and did not affect the ratio of pulmonary to systemic vascular resistance (Rp/Rs). Diltiazem decreased pulmonary artery pressure 15%, decreased Rp 50%, and did not affect Rp/Rs. When 0.33 mL/kg polyethylene glycol-ethanol vehicle (the vehicle used for nifedipine administration in a prior study) was administered during diltiazem infusion, pulmonary artery pressure increased 19%, Rp increased 72%, and Rp/Rs increased 29%. These results indicate that diltiazem is an effective pulmonary vasodilator and suggest that the previously reported unfavorable results of nifedipine may have been due to the vehicle used for nifedipine administration.
Preoperative stabilisation in congenital diaphragmatic hernia. Between January 1983 and November 1986, 26 newborn infants with congenital diaphragmatic hernia were treated by early operation at a mean of 7 hours of age. A further 23 infants admitted between December 1986 and December 1989 were stabilised for a mean period of 40 hours before operation. There was no significant difference in survival between the two groups. Delayed operation is not detrimental to infants with congenital diaphragmatic hernia.
Stage IV neuroblastoma in infants. Long-term survival. Before the advent of multiagent chemotherapy, the prognosis for patients with Stage IV neuroblastoma of all ages was dismal. More recently, marked improvement in infants with Stage IV neuroblastoma has been reported. Twenty-four infants with Stage IV neuroblastoma have been treated at the Dana-Farber Cancer Institute/The Children's Hospital, and the Joint Center For Radiation Therapy, Boston, Massachusetts, between 1970 and 1988. Twenty-three of these patients were treated with multiagent chemotherapy and one with a single drug. In the initial report, ten of 11 patients were alive without evidence of disease after intensive therapy. In this report the authors update their initial series of patients and include 13 additional patients who subsequently presented to our institutions with Stage IV neuroblastoma younger than 1 year of age. The 5-year actuarial event-free survival for the 24 patients is 75%. No patient without bone metastases died from neuroblastoma, and 12 of 16 patients with bone metastases remained disease free. These results confirm that infants with Stage IV neuroblastoma have a very good prognosis when treated with intensive multiagent chemotherapy.
Secondary T-cell lymphoproliferation after marrow transplantation. Secondary lymphoproliferative syndromes in immunosuppressed patients have been characterized as polyclonal or monoclonal B-lineage disorders nearly always associated with Epstein-Barr virus (EBV) infection. The authors now report three patients with a distinctly different lymphoproliferative syndrome. Two patients with common acute lymphoblastic leukemia antigen (CALLA) (CD10)-positive acute lymphoblastic leukemia and one patient with acute myelogenous leukemia, respectively, received high-dose chemoradiotherapy followed by marrow transplantation from either an HLA-identical sibling or HLA-mismatched parent. All three patients developed severe graft-versus-host disease (GVHD), requiring immunosuppressive treatment with corticosteroids. A secondary malignant T-cell lymphoproliferation occurred 2, 21, and 43 months, respectively, after marrow transplantation. In all three cases the lymphoid cells expressed T-cell surface antigens and were morphologically and immunophenotypically distinct from the malignant cells present before transplantation. One tumor was of host cell origin, one was probably of donor origin, and the tumor origin in the third case could not be determined. The authors were unable to find any evidence for EBV, human T-cell lymphotropic virus type I or II, human immunodeficiency virus, or human herpesvirus 6.
Preoperative evaluation and surgical treatment for tricuspid regurgitation associated with acquired valvular heart disease. The Kay-Boyd method vs the Carpentier-Edwards ring method. This study compared the results of annuloplastic repair of tricuspid regurgitation (TR) using Doppler echocardiography. Sixty-three patients who underwent tricuspid annuloplasty were studied. Thirty-four patients received Kay-Boyd annuloplasty and 29 Carpentier-Edwards ring annuloplasty. A new classification of TR based on the direction and area of regurgitation flow on Doppler echocardiogram was applied preoperatively. In the Kay-Boyd group, 10 cases showed massive TR and 24 cases showed localized TR preoperatively. Localized TR was well controlled in all cases, but 8 of 9 cases of massive TR showed grade III residual TR. In the C-E group, 21 cases showed massive TR and 8 cases showed localized TR. All cases were well controlled postoperatively. We conclude that (1) although the Kay-Boyd method is acceptable for localized TR, the C-E method should be employed for massive TR; (2) analyzing the regurgitant pattern of TR by Doppler echocardiogram is useful in selecting an appropriate surgical technique.
Lung vascular injury after administration of viable hemolysin-forming Escherichia coli in isolated rabbit lungs. Escherichia coli hemolysin, a transmembrane pore-forming exotoxin, is considered an important virulence factor. In the present study, the possible significance of hemolysin production was investigated in a model of septic lung failure through infusion of viable bacteria in isolated rabbit lungs; 10(4) to 10(7) E. coli/ml perfusate caused a dose- and time-dependent appearance of hemolysin, accompanied by release of potassium, thromboxane A2, and PGI2 into the perfusate. Concomitantly, marked pulmonary hypertension developed. Inhibitor studies suggested that the pressor response was predominantly mediated by pulmonary thromboxane generation. Administration of hemolysin-forming E. coli additionally caused a protracted, dose-dependent increase in the lung capillary filtration coefficient, followed by severe edema formation. The permeability increase was independent of lung prostanoid generation. An E. coli strain that releases an inactive form of hemolysin completely failed to provoke the described biophysical and biochemical responses. Preapplication of 2 x 10(8) human granulocytes was without effect in the present experimental model. We conclude that the hemolysin produced by low numbers of E. coli organisms can provoke thromboxane-mediated pulmonary hypertension and severe vascular leakage. E. coli hemolysin and, possibly, other related cytolysins may thus contribute directly to the pathogenesis of acute respiratory failure under conditions of sepsis or pneumonia.
Immunopathology and viral reactivation. A general theory of schizophrenia. A theory is proposed that explains a broad range of clinical manifestations in schizophrenia. It is a heuristic device for organizing research in the neuroimmunology and virology of schizophrenia. This approach is different from other immune and viral theories of schizophrenia and defines testable hypotheses for further theory refinement or rejection. Defective alpha-interferon (aIFN) regulation resulting in excessive effect is postulated to cause schizophrenia. The role of aIFN in the regulation of development and its induction within the brain by the reactivation of viruses that are commonly present in the normal central nervous system (CNS) are the primary pathophysiological mechanisms. Biological properties of aIFN include neural excitation, opiate and adrenocorticotropic hormone activity, and inhibition of cellular proliferation and differentiation. Psychosis results from in situ viral stimulation of aIFN production in the CNS of a vulnerable host having defective regulation of either sensitivity or production. Negative symptoms result from aIFN effects on CNS development and the behavioral toxicity of aIFN. Biological developmental abnormalities, gender differences in severity, and decline in psychotic symptoms with age are discussed in the context of the theory. Research strategies and specific testable hypotheses are presented.
A case of classical mycosis fungoides associated with human T-cell lymphotropic virus type I. A 72-year-old male patient from north-eastern Iran developed the typical clinical and histopathological features of mycosis fungoides with lymphadenopathy, but without any other systemic involvement. Human T-cell lymphotropic virus (HTLV-I) antibodies were detected in the patient's serum by two different ELISAs and by Western blot using purified viral particles from MT-2 culture supernatants. Cultured peripheral blood lymphocytes were positive for labelling with anti-HTLV-I serum. Southern blot hybridization of DNA extracted from a skin tumour and from an involved lymph node revealed integrated proviral DNA with identical restriction patterns. This case supports a relationship between mycosis fungoides and HTLV-I and may indicate a new region of endemic HTLV-I infection.