123rc/medical_text huggingface dataset:
The surgical treatment of atrial fibrillation. IV. Surgical technique. The operative technique for the current surgical procedure of creating an electrical maze for the treatment of atrial fibrillation is described in a sequential fashion. The accompanying diagrams of the procedure are drawn from the view of the operating surgeon.
The renin-angiotensin system and renal function in kidney transplantation. The use of converting enzyme inhibitors (CEI) has permitted us to assess the role of the renin-angiotensin system in the control of arterial pressure and renal function in various conditions. In renal transplant recipients treated by azathioprine and steroids, the occurrence of CEI-induced deterioration of renal function is highly suggestive of renal artery stenosis, whereas renal vasodilatation associated with unchanged glomerular filtration rate in response to CEI is indicative of a significant role of native kidneys. In hypertensive recipients without renal artery stenosis, the absence of renal hemodynamic changes after CEI may be predictive of subsequent chronic rejection. The information provided by CEI is rather different in cyclosporine treated subjects. In this setting, no acute effect of CEI on renal hemodynamics is detectable. Whether the renal response to CEI is similar in cyclosporine when compared to conventionally treated patients with renal artery stenosis remains to be demonstrated.
Primary malignant fibrous histiocytoma of the aorta associated with aortic dissection. We report a unique case of primary aortic malignant fibrous histiocytoma presenting clinically as aortic dissection. To our knowledge, this occurrence is the first ever reported. The magnetic resonance imaging technique may provide superiority in the differential diagnosis between tumor and hematoma of aortic dissection. Aortic tumor, although rare, should be included among the causes of aortic dissection.
Adrenal medullary implants in the rat spinal cord reduce nociception in a chronic pain model. Previous work in this laboratory has indicated that the transplantation of adrenal medullary tissue into the subarachnoid space of the rat spinal cord can reduce pain sensitivity to acute noxious stimuli, particularly following stimulation by nicotine. This most likely results from the stimulated release of opioid peptides and catecholamines from the transplanted chromaffin cells. However, chronic pain models may more closely resemble human clinical pain, and the arthritic rat model has been used for screening potential therapeutic strategies. The purpose of the present study was to assess the potential for adrenal medullary tissue implanted into the spinal subarachnoid space to alleviate chronic pain. Adrenal medullary tissue was implanted into adjuvant-induced arthritic rats, and changes in body weight and vocalization responses were monitored over the 10 week course of the disease. Results indicate that the severe weight reduction normally associated with this inflammatory arthritis was attenuated by adrenal medullary, but not control, implants. In addition, vocalizations were reduced in animals implanted with adrenal medullary, but not control tissue following nicotine stimulation. This reduction was blocked by the opiate antagonist, naloxone, and partially attenuated by the alpha-adrenergic antagonist, phentolamine. Together, these results suggest that the transplantation of adrenal medullary tissue into the subarachnoid space of the spinal cord may provide a local source of opioid peptides and catecholamines for the reduction of chronic pain.
Dynamic CT scanning of pancreatic duct after secretin provocation in pancreas divisum. Variations in pancreatic duct diameter at CT scanning and serum pancreatic amylase response following secretin administration were studied in 29 patients with pancreas divisum and unexplained upper abdominal pain. Eleven healthy individuals were used as controls. At endoscopic retrograde pancreatography (ERP) six patients had signs of marked and six moderate pancreatitis, whereas there were no pancreatitis changes in 17 of the patients. At CT scanning patients with marked pancreatitis (ERP) had significantly increased pancreatic duct diameter as compared to patients without signs of pancreatitis. The duct was visualized in 52% of all patients before and 71% after secretin stimulation the corresponding figures for healthy controls, being 18% both before and after secretin. In patients without signs of pancreatitis, it was demonstrated in 5/17 (29%) before and 11/17 (65%) after secretin, whereas it was seen in 10/12 (83%) pancreatitis patients both before and after the hormonal provocation. In five of the nonpancreatitis patients in whom the duct was measurable before and at all study intervals (10, 20, and 50 min) after secretin, there was a significant duct dilation response both at 10 min and when comparing the maximal duct diameter after secretin to the initial values. In contrast secretin did not affect the duct caliber in pancreatitis patients. Serum pancreatic amylase increased significantly after secretin administration to healthy controls and nonpancreatitis patients but was uninfluenced in the marked and moderate pancreatitis groups, respectively. However, when all pancreatitis patients were grouped together, the amylase levels were significantly elevated by secretin. In conclusion, secretin provocation caused duct dilation at CT scanning in pancreas divisum patients without signs of pancreatitis at ERP.
Assessment of middle-ear status during experimental otitis media using magnetic resonance imaging. Magnetic resonance imaging has proved to be a useful tool for in vivo imaging of a variety of tissues. In this study, magnetic resonance imaging was applied to the middle ear of experimental animals with otitis media. Results showed that the presence and distribution of effusion within the middle-ear space could be readily determined. Moreover, following injection of gadolinium-diethylenetriaminepentaacetic acid, a contrast agent, the inflamed middle-ear mucosa could be resolved. A comparison between magnetic resonance imaging and tympanometry with respect to the diagnosis of effusion showed that negative pressure tympanograms were equivocal (50% effusion) and that flat or normal tympanograms were in error in approximately 20% of the observations. These data document a role for magnetic resonance imaging in in vivo studies of the pathogenesis of otitis media with effusion.
Methsuximide for intractable childhood seizures. Methsuximide was added to the therapeutic regimens of 25 children with intractable epilepsy. In 15 patients the drug was well tolerated and resulted in a 50% or greater reduction in seizure frequency. No serious or irreversible adverse effects were seen. Methsuximide is frequently overlooked and may be an effective adjunctive antiepileptic for children with intractable seizures.
Thrombotic thrombocytopenic purpura treated with high-dose intravenous gamma globulin. Plasma infusion and/or plasma exchange has become standard therapy in the treatment of thrombotic thrombocytopenic purpura (TTP). The management of patients in whom such primary therapy fails is difficult and uncertain. We have described a patient who obtained a sustained remission with the use of high-dose IV gamma globulin after an initial response to aggressive plasma exchange was followed by prompt relapse. Our case and others suggest that high-dose IV IgG may induce remission in patients with TTP who do not respond to standard plasma infusion and/or exchange.
Doppler echocardiographic study of porcine bioprosthetic heart valves in the aortic valve position in patients without evidence of cardiac dysfunction. To study the natural history of the hemodynamic performance of bioprosthetic heart valves, Doppler echocardiograms were recorded in a group of clinically stable patients at 2 and 5 years after replacement of native aortic valves with bioprosthetic valves. Eighteen patients completed a 2-year and 26 patients a 5-year follow-up examination. The effective orifice areas of identical models of bioprosthetic valves (Hancock II) were determined in vitro in a left-sided heart pulse duplicator system. In vivo Doppler-derived effective orifice areas were compared with the in vitro measurements for the same valve size. At both the 2- and 5-year follow-up examinations, the Doppler-derived effective orifice area was significantly less than the in vitro area (p less than 0.0001 at each interval). Ten of 16 valves evaluated serially decreased greater than 0.20 cm2 in the Doppler-derived effective orifice area between studies. The mean decrease in effective orifice area in valves evaluated serially was 0.25 +/- 0.29 cm2 (p less than 0.005). The peak transaortic gradient increased from 21 +/- 6 to 27 +/- 8 mm Hg (p less than 0.01). The mean transaortic gradient increased from 12 +/- 4 to 15 +/- 7 mm Hg (p less than 0.05). It is concluded that serial Doppler echocardiographic studies demonstrate a deterioration in the hemodynamic performance of bioprosthetic valves over time in patients with no symptoms or signs of valvular dysfunction and that Doppler echocardiography may be useful for identifying subclinical bioprosthetic valvular dysfunction.
Dural spinal cord arteriovenous malformation. After multiple hospital admissions and an inpatient rehabilitation stay, a 68-year-old woman was transferred to our rehabilitation facility with a paraparesis of unknown etiology. Previous studies included four CT scans and three MRIs which did not demonstrate the lesion. A myelogram was noncharacteristic. The correct diagnosis, confirmed by selective angiography, was ultimately contingent upon recognition of the clinical features and natural history of dural spinal cord arteriovenous malformations (SCAVM). The unusual combination of this multitude of nondiagnostic imaging studies in the uncommon dural SCAVM served to delay diagnosis and treatment. Such delay may have great functional consequences. This report illustrates the importance of suspecting SCAVM and recognizing its features. Emphasis is placed on the physiatrist's role in assuring proper diagnosis to expedite a timely treatment and to obtain the best functional outcome. A brief review of the classification, clinical features, pathophysiology, diagnosis, and prognosis of SCAVM is presented.
The effect of race on the relationship between fetal death and altered fetal growth. This population study examines racial differences in the relationship between birth weight and fetal death. An earlier report showed that a birth weight that results in a fourfold increased risk of stillbirth is not a constant birth weight percentile (2nd percentile at 25 weeks, 17th percentile at 42 weeks). This analysis was applied to 782,430 white and black births in Illinois from 1980 to 1984. Mean and 10th percentile growth for white and black infants is identical before 34 weeks' gestation and growth diverges by 250 gm at term, with white infants being larger. Race-specific birth weights resulting in quadrupling of the stillbirth rate were determined with an exponential regression analysis of the relationship between birth weight and fetal death rate for each gestational age. The data indicate (1) that the birth weights resulting in quadrupling the stillbirth rate are substantially above the Denver 10th percentile and the previously unpublished race-specific Illinois 10th percentiles and (2) that at term white infants demonstrate this constant risk at the 12th percentile, whereas black infants exhibit the risk at the 18th percentile. From these data we conclude that black fetuses are more sensitive than white fetuses to factors that adversely affect growth and that continued use of "race-neutral" data for clinical management in racially heterogenous populations will not accurately predict the risk of stillbirth.
Hypertension and diabetes in blacks. This article summarizes the current state of knowledge on the interrelationship between non-insulin-dependent diabetes mellitus, obesity, insulin resistance, and hypertension in our attempt to explore the pathophysiology of the high incidence of diabetes and hypertension in the Black population in the United States. A central role for hyperinsulinemia is proposed, and questions are raised that are suitable for investigative clinical trials.
Decision criteria for pure-tone detection used by two age groups of normal-hearing and hearing-impaired listeners. Response criteria from a yes-no task and detection thresholds from two test procedures were measured for four groups of adults: younger normal-hearing, older normal-hearing, younger hearing-impaired, and older hearing-impaired. The two test procedures were an audiological procedure (which does not control for response bias) and a 21FC adaptive procedure (which does control for bias). The signal was a 500 or 4000 Hz tone presented in quiet. All four groups showed an equally conservative response bias in the yes-no task. In addition, neither age nor hearing loss affected the difference (6.5 dB) between the two threshold measures.
Hepatitis B vaccination and interleukin 2 receptor expression in chronic renal failure. Only 50 to 60% of dialysis patients develop anti-HBs antibodies following hepatitis B vaccination. The nonresponder state correlates with impaired monocyte function, decreased interleukin-2 (IL-2) production of T cells, and an upregulation of the IL-2 receptor system. In the present study we examined anti-HBs production after hepatitis B vaccination and the in vitro expression of IL-2 receptors in nondialyzed patients with various degrees of chronic renal failure. Forty-four patients with impaired renal function were immunized with 2 micrograms recombinant hepatitis B vaccine and boostered after one and six months. Prior to the first injection IL-2 receptor expression of activated T cells was studied by an in vitro proliferation assay. Sixty-four healthy subjects served as controls. After completion of the third vaccination 55.0% of the patients acquired antibody titers greater than 10 U/liter. The seroconversion rate did not differ between patients with lower (less than 3.5 mg/dl) and higher (greater than 3.5 mg/dl) creatinine levels. In nonresponders IL-2 receptor expression (stimulation index, SI = 10.09 +/- 1.80) was elevated compared to healthy controls (SI = 4.62 +/- 0.35, P less than 0.002) or patients who responded with a high antibody titer (greater than 50 U/liter, SI = 3.12 +/- 0.43, P less than 0.001). Patients who produced low antibody titers (less than 50 U/liter) also presented with enhanced IL-2 receptor expression. These data show that an impaired antibody production following hepatitis B vaccination and an enhanced IL-2 receptor expression of T cells may already be present in early stages of chronic renal failure.
Adenovirus 12S E1A gene represses differentiation of F9 teratocarcinoma cells. The F9 teratocarcinoma cell line differentiates in vitro after treatment with retinoic acid and cAMP and has been a widely used model system for the study of the molecular events that are responsible for cellular commitment and differentiation during early development. Previous experiments have suggested intriguing parallels between the control of gene expression during F9 cell differentiation and the regulation of gene expression by adenovirus E1A. Transfection of a 12S E1A-expressing plasmid into terminally differentiated, nonproliferating F9 cells generates, at high frequency, colonies of dividing cells, each of which expresses E1A. Cell lines established from these colonies proliferate in the presence of retinoic acid and have lost the fully differentiated phenotype as characterized by the absence of expression of a series of differentiation-specific genes. We conclude that expression of the viral 12S E1A gene product interferes with retinoic acid-induced F9 cell differentiation. Moreover, the results suggest that the differentiation process, as defined by markers of terminal differentiation, may not be a permanent event but can be reversed by E1A expression.
Lymphoma, motor neuron diseases, and amyotrophic lateral sclerosis. We studied 9 patients with motor neuron disease and lymphoma. The following several observations have not been recognized in the past: (1) Motor neuron syndromes are associated with either Hodgkin's disease or non-Hodgkin's lymphoma. (2) The syndromes are not restricted to lower motor neuron disorders; 8 of 9 patients had definite or probable upper motor neuron signs as well, qualifying for the diagnosis of amyotrophic lateral sclerosis. Corticospinal tracts were affected in both postmortem examinations. (3) The combination of motor neuron disease and lymphoma is often accompanied by paraproteinemia (3 of 7 patients studied), increased cerebrospinal fluid protein content (6 of 9 patients), and cerebrospinal fluid oligoclonal bands (3 of 9 patients). (4) In 2 patients, asymptomatic non-Hodgkin's lymphoma was found only because the discovery of paraproteinemia gave impetus to examine the bone marrow. (5) Patients with both upper and lower motor neuron signs (amyotrophic lateral sclerosis) may show physiological evidence of conduction block in peripheral nerves or autopsy abnormalities in peripheral nerves. The cause of this syndrome is not known. Both lymphoma and motor neuron disease could have a common cause, possibly a retroviral infection. The frequency of paraproteinemia suggests that an immunological disorder may play a role in the pathogenesis of the neurological disorder.
Computed tomography-guided fine-needle aspiration of retroperitoneal lymph nodes in gynecologic oncology. Computed tomography-guided fine-needle aspiration was performed on 30 retroperitoneal lymph nodes in 29 patients with gynecologic cancer. There were no serious complications. Review of the cytologic material demonstrated malignant cells in 83% of the aspirates. Because the predictive value of a positive aspirate approaches 100%, therapy for metastatic disease can be initiated in these patients with the need for an open biopsy. Among five aspirates in which malignant cells were not seen, the cellularity of the specimen appeared to be the critical factor determining the predictive value of the aspirate. Whereas neither of two patients with negative aspirates of adequate cellularity has developed recurrent disease, two of three patients with hypocellular negative aspirates have. Because a hypocellular negative aspirate from a retroperitoneal lymph node may not be a true reflection of disease status, either repeat aspiration or open biopsy is advisable.
Experimental models of temporal lobe epilepsy: new insights from the study of kindling and synaptic reorganization. Temporal lobe epilepsy is a common localization-related epileptic syndrome characterized by complex partial seizures, ictal and interictal epileptic discharges arising from limbic structures of the temporal lobe, and association with hippocampal sclerosis. Temporal lobe epilepsy may follow perinatal injury and febrile convulsions, may be progressive, and frequently becomes refractory to standard antiepileptic therapy. The neurobiology that underlies these features of temporal lobe epilepsy is not known. Recent studies in experimental models have provided new insights that may help clarify the relationship of seizures, hippocampal sclerosis, and temporal lobe epilepsy. Observations from the study of the hippocampus with kainic acid-induced lesions, the kindling model, and other experimental models of epilepsy have demonstrated that seizures induce structural and electrophysiologic alterations in hippocampal pathways that may lead to increased excitability and could play a role in the development and progression of temporal lobe epilepsy. These alterations include mossy fiber synaptic reorganization, induction of NMDA-mediated synaptic transmission, and progressive hippocampal neuronal loss induced by brief kindled seizures. Some of the structural alterations induced by kindling have also been observed in the human epileptic temporal lobe, raising the possibility that mechanisms operative in kindling may play a role in the pathogenesis of hippocampal sclerosis and in the syndrome of human temporal lobe epilepsy.
Induction of mixed erythroid-megakaryocyte colonies and bipotential blast cell colonies by recombinant human erythropoietin in serum-free culture. The effects of recombinant human erythropoietin (rEp) on murine hematopoietic progenitors were studied using a serum-free culture. A high concentration of rEp stimulated the formation of mixed erythroid-megakaryocyte colonies (EM colonies) and blast cell colonies, as well as erythroid colonies, erythroid bursts, and megakaryocyte colonies from normal mouse bone marrow cells. Direct effects of rEp on EM colony, megakaryocyte colony, and erythroid burst formation were confirmed by depletion of accessory cells such as T cells, B cells, and macrophages from crude bone marrow cells, and inhibition of the colonies by the addition of rabbit anti-rEp antibody to the culture in a dose-dependent fashion. Replating experiments were performed to confirm the differentiating ability of blast cell colonies grown in the presence of rEp. Most of the blast cell colonies yielded not only secondary erythroid colonies but also megakaryocyte colonies in the presence of 2 IU/mL rEp. Some of the blast cell colonies produced secondary EM colonies in the presence of 16 IU/ml rEp of 2 IU/mL rEp plus interleukin-3, although no granulocyte-macrophage colonies were found in the secondary culture. These results suggest that Ep acts not only as a late-acting factor that is specific for erythroid progenitors, but also as a bipotential EM-stimulating factor for murine hematopoietic cells.
Intracranial pressure and cerebrospinal fluid outflow conductance in healthy subjects. Conductance of cerebrospinal fluid (CSF) outflow (Cout) is an important parameter to be considered in patients with CSF circulation abnormalities. In patients with normal-pressure hydrocephalus it is the single most important parameter in determining if the patient needs CSF shunting. The lower normal limit for Cout has been estimated from the effect of shunting in patients with normal-pressure hydrocephalus, from patients retrospectively reevaluated after recovering from illness, and from patients with known abnormalities in the brain or the CSF system. The true value of Cout in normal individuals, however, has hitherto not been reported. In the present study, Cout has been measured by a lumbar infusion test in eight young volunteers with no suspicion of disease. The mean intracranial pressure (ICP) was 11 mm Hg and a linear relationship was found between CSF absorption and ICP. The mean Cout was 0.11 ml/min/mm Hg and the lower 95% confidence level was 0.10 ml/min/mm Hg. These values are in accordance with those obtained from previous studies.
Levels of serum granulocyte colony-stimulating factor in patients with infections. To clarify the physiologic roles of granulocyte colony-stimulating factor (G-CSF) in infectious states in vivo, we examined the serum levels of G-CSF in patients with infection. Serum samples from 24 patients in the acute stage of infection (14 men and 10 women, age 65 to 101, without hematologic disorders), as well as samples from 32 age-matched normal elderly volunteers were investigated. Sixteen of the initial 24 patients were reexamined after the recovery phase. G-CSF levels were examined by quantitative enzyme immunoassay. The G-CSF level in normal elderly controls, 25.3 +/- 19.7 pg/mL, was not different from that reported in other findings. There was no statistically significant relationship between their G-CSF level and peripheral white blood cell count or neutrophilic granulocyte count. The G-CSF level in the acute stage of infection was 731.8 +/- 895.0 pg/mL, with a range of 30 to 3,199 pg/mL. There was no significant difference in G-CSF levels between patients with respiratory tract infection and those with urinary tract infection. In all 16 cases examined, the serum G-CSF level in the acute stage of infection was significantly higher than that after recovery phase, the latter being the same as the level in normal elderly controls. G-CSF must therefore play a significant role in human infectious states in vivo.