ISSN:0002-9629    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

The Tuskegee Study, an observational study of over 400 sharecroppers with untreated syphilis, was conducted by the U.S. Public Health Service to document the course of the disease in blacks, and racial differences in the clinical manifestations of syphilis. The men were not told they had syphilis, not given counseling on avoiding spread of the disease, and not given treatment throughout the course of the study. The study became the longest (1932-1972) nontherapeutic experiment on humans in the history of medicine, and has come to represent not only the exploitation of blacks in medical history, but the potential for exploitation of any population that may be vulnerable because of race, ethnicity, gender, disability, age or social class. It is important for physicians who will be caring for an increasingly diverse nation to understand the lasting implications of this study for their patients, but the effects of the Tuskegee Syphilis Study are demonstrated most strikingly by unsuccessful attempts at improving representation of minority patients in clinical trials.

ISSN:0002-9629    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Hypotension during hemodialysis in end-stage renal disease (ESRD) not explained by excessive ultrafiltration has been linked to an apparent increase in the synthesis of nitric oxide (NO). The authors tested whether the induction of NO synthase (iNOS) by cytokines or differences in the concentrations of inhibitors of NOS or both could account for variability in the amount of NO synthesized during hemodialysis. Plasma levels of an inhibitor of NOS, asymmetric dimethylarginine (ADMA), L-arginine, the substrate for NOS, the end-products NO2+NO3, iNOS activity in circulating buffy coat cells, and their interdialytic changes were measured in 10 patients during three treatments. Predialysis (0′) levels of ADMA were markedly elevated with a mean of 0.008 ± 0.002 µmol/mL of deproteinized plasma, compared to controls where ADMA is present in trace amounts. ADMA levels from 30 minutes to the end of dialysis correlated directly with the drop in blood pressure (BP), with levels being much higher in patients with severe hypotension. Postdialysis ADMA levels correlated directly with the 0′ systolic BP and the drop in BP at the next dialysis treatment. NOS activity was detected in two thirds of the predialysis buffy coat samples, and appeared to increase as dialysis progressed. 0′ iNOS activity correlated inversely with the 0′ BP, but activities did not differ based on percent drop in BP. iNOS activity in the 0′ samples correlated inversely with the time since the last dialysis, reflecting the greater accumulation of dialyzable inhibitors of NOS as the interval is prolonged. The interdialytic change in iNOS activity correlated inversely with the drop in BP. The isoform detected immunochemically in the buffy coat samples had an Mrof 130 kDa and was reactive with antihuman iNOS. Thus, iNOS is already induced in the cells of the buffy coat in many intermittently hemodialyzed ESRD subjects, but its expression may be masked by inhibitors. After 60 minutes of dialysis (too brief a time for the de novo induction of iNOS), the appearance of or increase in iNOS activity suggests that an inhibitor had been removed. Because ADMA levels are associated with higher predialysis systolic BPs that result in a greater severity of hypotension, reduction in ADMA concentrations would appear to play a major role in the resumption of NO synthesis by various isoforms.

ISSN:0002-9629    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Background:There has been little systematic study of the clinical spectrum of pancytopenia, and the optimal diagnostic approach to pancytopenia remains undefined.Methods:The authors studied 134 hospitalized pancytopenic patients in Zimbabwe in both consecutive and nonconsecutive fashion.Results:The most common cause of pancytopenia was megaloblastic anemia, followed by aplastic anemia, acute leukemia, acquired immunodeficiency syndrome (AIDS), and hypersplenism. Severe pancytopenia was usually due to aplastic anemia. Patients with aplastic anemia and acute leukemia were usually children, whereas those with megaloblastic anemia were adults. Moderate to severe anemia was noted throughout the series, but was most striking in patients with megaloblastic anemia, aplastic anemia, and acute leukemia. The mean corpuscular volume (MCV) was elevated in most patients with megaloblastic hematopoiesis, aplastic anemia, and acute nonlymphocytic leukemia. Normal or low MCV values were noted in almost one third of patients with megaloblastic anemia. Anisocytosis, poikilocytosis, macroovalocytosis, microcytosis, fragmentation, and teardrop erythrocytes were more prominent on the blood films of patients with megaloblastic anemia.Conclusions:Megaloblastic anemia, aplastic anemia, and AIDS are the most common causes of pancytopenia in Zimbabwe. Aplasia is the most frequent cause of severe pancytopenia. The authors have formulated tentative guidelines for the evaluation of pancytopenic patients in this setting.

ISSN:0002-9629    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

The authors measured gastric emptying in 13 patients undergoing radiation therapy to the chest, abdomen, or pelvis for nongastrointestinal cancer to investigate whether gastric emptying (GE) was altered by this therapy. Symptoms and weight were monitored at regular intervals. Patients served as their own controls and were compared to a group of healthy subjects. When studied prior to radiation therapy (baseline), cancer patients had a gastric emptying rate that was similar to a healthy control group (t1/2 mean ± SEM 92.0 ± 15.3 vs. 80.4 ± 8.2 min). Irradiation did not change the emptying rate, either after the first dose (early) of 180 cGy (t1/2 99.5 ± 17.9) or after 2 weeks of therapy (late) with 3000 cGy (t1/2 75.5 ± 7.3). There was no correlation of radiation field or tumor type with gastric emptying rate. Two of the 13 patients experienced nausea and vomiting during their course of radiation, but their gastric emptying was unchanged from baseline.

ISSN:0002-9629    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

A patient with severe metabolic acidosis and an extremely elevated (57 mEq/L) serum anion gap (AG) is described, and the multiple factors that produced the patient's complex abnormalities are discussed in detail. These include renal failure, rhabdomyolysis, marked hyperphosphatemia, hemoconcentration, and an unidentified organic metabolic acidosis. A review of the literature indicates that the common thread observed in almost each instance of profoundly elevated AG values is a multifactorial pathogenesis that usually includes renal insufficiency, associated with a proven or likely cause of organic metabolic acidosis, or with exogenous phosphate intoxication.

ISSN:0002-9629    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Simple parathyroid cysts are rare; only about 200 cases have been reported in the literature. The diagnosis was facilitated recently by parathyroid hormone assay of the cyst fluid. Standard treatment consists of percutaneous aspiration of the cyst and surgical excision for recurrent lesions. Sclerotherapy of recurrent lesions was described in two cases and results were promising. The authors report a new case of recurrent nonfunctioning parathyroid cyst in a 34-year-old female, with complete resolution after ethanol sclerosis and no recurrence for 15 months of follow-up. Ethanol sclerotherapy is recommended as a simple and safe treatment for recurrent parathyroid cysts.

ISSN:0002-9629    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

The authors report a case of a patient who received alteplase for acute myocardial infarction and developed spontaneous subfascial hematoma without any evidence of direct trauma. Subfascial hematoma remains a rare and self-limited complication of thrombolytic therapy. The development of cutaneous ecchymosis associated with a sudden fall in hemoglobin after the administration of alteplase should strongly suggest the possibility of diffuse subfascial hematoma. Physicians should be aware of the possible association between the use of alteplase and the development of subfascial hemorrhage.

ISSN:0002-9629    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

The authors report a case of a suspected pure pancreatic polypeptide-secreting neuroendocrine carcinoma of the gallbladder. The tumor was initially interpreted as an adenocarcinoma of the gallbladder, but was found to have a neuroendocrine component after review. The pathology supports the view that a primitive epithelial stem cell can express both epithelial and neuroendocrine characteristics and can differentiate into both an adenocarcinoma and a neuroendocrine carcinoma. Upon recurrence, the tumor produced symptoms due to local growth, but eventually metastasized and led to the death of the patient within 4 years. The patient was treated with chemoembolization followed by the long-acting somatostatin analog octreotide acetate. The high serum level of pancreatic polypeptide may have contributed to cholestasis and cholelithiasis. Earlier measurement of serum hormone levels and identification of high pancreatic polypeptide levels may have suggested the presence of residual tumor and led to closer follow-up, imaging studies, and therapy.

ISSN:0002-9629    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Various extraintestinal manifestations may occur in juvenile polyposis, but hereditary hemorrhagic telangiectasia has rarely been reported in this type of polyposis. The authors treated a 14-year-old girl with rectal bleeding and anemia who had multiple polyps of the colorectum. Large polyps were removed and histologically diagnosed as juvenile polyps. She was later diagnosed as having telangiectasia of the skin, and arteriovenous malformations in the lung and in the liver, all of which were compatible with the diagnosis of hereditary hemorrhagic telangiectasia. At age 32, she had multiple ulcers in the ileum and in the colon. The coexistence of juvenile polyposis and hereditary hemorrhagic telangiectasia may be a clue for the understanding of the histopathogenesis of juvenile polyposis.

ISSN:0002-9629    

出版商:OVID    

年代:1999

数据来源: OVID