123rc/medical_text huggingface dataset:
Rigid fixation of internal orbital fractures. When large portions of the internal orbit are destroyed (two to four walls), standard bone-grafting techniques for immediate and late orbital reconstruction may not yield predictable eye position. Critical bone support is most often deficient inferomedially. CT analysis of orbital volume in cases where eye position was unsatisfactory reveals that displacement of bone grafts is one mechanism of the unsatisfactory result. Other mechanisms include undercorrection and bone-graft resorption. In order to minimize postoperative bone-graft displacement, titanium implants were used to span large defects in the internal orbit to provide a platform for bone-graft support. Twenty-six implants were placed in immediate and 12 were placed in late orbital reconstructions. More reliable bone-graft position resulted. Two late infections have occurred resulting in implant removal in a 3-year period.
Ischemic optic neuropathy. ION typically affects the older population with a sudden decrease in vision, altitudinal visual field loss, and a swollen optic nervehead. Systemic hypertension and diabetes mellitus are the most commonly associated medical problems. Occlusion of the posterior ciliary arterial blood supply to the retrolaminar optic nerve leads to axoplasmic stasis and further compromise of vessels in the nerve substance, which causes the typical funduscopic appearance. Although there is no recognized medical treatment that can reverse the visual loss, a recent report suggests optic nerve sheath decompression for a select group of patients with a gradual decline in vision due to ION may be beneficial. When ION occurs in persons less than 50 years of age, such etiologies as juvenile diabetes mellitus, antiphospholipid antibody-associated clotting disorders, collagen-vascular disease, and migraines should be considered. Rarely, complications of intraocular surgery or acute blood loss may cause an ischemic event in the optic nerve.
A phase II multi-institutional trial of low-dose N-(phosphonacetyl)-L-aspartate and high-dose 5-fluorouracil as a short-term infusion in the treatment of adenocarcinoma of the pancreas. A Southwest Oncology Group study. Adenocarcinoma of the pancreas is a highly lethal malignancy and chemotherapy has had little impact on the natural history of this disease. PALA, used to potentiate 5-fluorouracil (5-FU), has been shown to have synergy in vivo and in vitro. Twenty-seven patients were treated with an intravenous push dose of PALA (250 mg/m2) followed 24 hours later with a 24-hour infusion of 5-FU (2600 mg/m2). This regimen was repeated weekly. There was one partial response of 21 eligible patients with an estimated response rate of 5%. Toxicity was severe with one toxic death and four patients experiencing Grade 4 toxicity. 5-Fluorouracil and PALA, given in the schedule described, do not appear to be effective against adenocarcinoma of the pancreas.
Mechanisms of hemolysis and anemia associated with acute antepartum pyelonephritis. Anemia develops in about a fourth of women whose pregnancy is complicated by pyelonephritis, although its exact mechanism has not been defined clearly. In this study of 18 women with antepartum pyelonephritis, although only a third had anemia (hematocrit less than 30 vol/dl), there was evidence for hemolysis in all 18. Specifically there was a mean decrease in hematocrit of 5 vol/dl from admission to discharge. With scanning electron microscopy, we compared erythrocyte morphologic aberrations that were found in women with renal infection with those of normally pregnant women, and the former had significantly increased proportions of echinocytes in particular, but schistocytes and spherocytes were increased also (total 10.3% vs 1.4%, p less than 0.0001). These changes, especially echinocytosis, have been induced in vitro by lipopolysaccharide, and they are known to lead to premature red blood cell destruction in vivo. We conclude that hemolysis with subsequent anemia in pregnant women with pyelonephritis is caused by lipopolysaccharide-induced red blood cell membrane damage.
Reliability of stimulated and spontaneous growth hormone (GH) levels for identifying the child with low GH secretion. The reliability of stimulated and spontaneous GH levels for identifying the child with low GH secretion has been the subject of debate. We compared the ability of GH concentrations after pharmacological stimulation with levodopa and clonidine and of spontaneous peak and 12-h pooled GH concentrations during sleep on a single night to estimate the maximum spontaneous GH secretion from 2 nights in 55 children, aged 5-16 yr, with heights below the 3rd percentile and/or height velocities below the 25th percentile for age, who had two consecutive overnight GH secretory profiles. Maximum stimulated GH concentrations correctly categorized 80% of children who had maximum spontaneous GH concentrations above and below 4 micrograms/L using a double monoclonal immunoradiometric assay for GH (Tandem-R HGH, Hybritech). The remaining 20% of children had stimulated GH concentrations below but spontaneous GH concentrations above 4 micrograms/L. Using this cut-off, the maximum GH concentrations from the first and second nights correctly categorized 98% and 95% of the children, respectively. Night to night variation in GH secretion was low in children who had low spontaneous GH secretion (maximum spontaneous peak and pool GH concentrations, less than 4 and less than or equal to 0.7 micrograms/L, respectively), and pooled GH concentrations from the 2 nights were concordant in 98% of the cases. We conclude that it is not uncommon for stimulated GH concentrations to underestimate spontaneous GH secretion. Even without acclimatization to the hospital setting, measurement of spontaneous GH secretion on a single night was more reliable for identifying the child with low endogenous GH secretion than was GH stimulation testing alone.
Decreased protein binding of salicylates in Kawasaki disease. Because patients with Kawasaki disease have low serum concentrations of salicylates despite high doses, and because the free (unbound) drug is responsible for the pharmacologic effects of salicylates, we assessed salicylate protein binding in patients with Kawasaki disease. During the acute phase of the disease, protein binding of salicylate in 36 children with Kawasaki disease was 73 +/- 12%, significantly lower than during the subacute phase (90.4 +/- 8.7%; p less than 0.0005). Mean serum albumin concentration was 29.2 +/- 6.4 gm/L during the acute phase and 36.7 +/- 7.8 gm/L during the subsequent subacute phase (p less than 0.005). Salicylate protein binding was affected independently by both serum albumin and total salicylate levels. During the acute phase of Kawasaki disease, children had an average twofold increase in free salicylate compared with normoalbuminemic control subjects. A nomogram has been devised to derive free salicylate levels from the known total salicylate and serum albumin concentrations.
Transoesophageal echocardiography in the longitudinal axis: correlation between anatomy and images and its clinical implications. Transoesophageal echocardiographic imaging in the longitudinal axis is a recent addition to the non-invasive evaluation of congenital and acquired heart disease. The technique provides unique images of intracardiac anatomy but their interpretation remains difficult. A heart specimen was therefore cut according to the echocardiographic imaging planes to elucidate the morphological details. The results suggested that longitudinal transoesophageal imaging complements the transverse axis approach. It gave new imaging information on the right ventricular outflow tract and the pulmonary trunk, the atrioventricular valves, the interventricular septum, the cardiac apex, and the thoracic aorta. In particular, it showed the entire length of the right ventricular outflow tract. When longitudinal imaging was used in combination with transverse imaging almost all the thoracic aorta could be examined. Imaging in the longitudinal axis may also allow better assessment of the mechanisms of atrioventricular valve regurgitation.
Postoperative active specific immunization in colorectal cancer patients with virus-modified autologous tumor-cell vaccine. First clinical results with tumor-cell vaccines modified with live but avirulent Newcastle disease virus [published erratum appears in Cancer 1991 Apr 15;67(8):2124] Sixteen patients with colorectal carcinoma Dukes' Stage B2, C, or D were treated with an autologous virus-modified tumor-cell vaccine after potential curative tumor resection (R0-Resection). An inoculum of 1 X 10(7) cells incubated with 32 hemagglutination units of nonirradiated Newcastle disease virus (NDV) was given intracutaneously up to four times at 10-day intervals. The delayed-type hypersensitivity (DTH) skin reaction was measured. The vaccination was well tolerated. In 11 of 16 patients an increasing reactivity against the vaccine was observed during the vaccination procedure. A challenge test using autologous tumor cells without NDV after the vaccination cycle revealed a specific antitumor sensibilization in 12 patients. The DTH response was not due to bacterial contamination or sensibility to the virus. Histologic examination of the vaccination site showed a dense infiltration of predominantly helper T-lymphocytes. We conclude that in most of the patients treated active, specific immunization led to a specific antitumor sensitivity.
Interleukin-6 (IL-6) is an intermediate in IL-1-induced proliferation of leukemic human megakaryoblasts. We have examined the in vitro effects of recombinant human (rh) interleukin-1 (IL-1) on the growth of purified megakaryoblasts obtained from patients with acute megakaryoblastic leukemia. We demonstrate that both IL-1 alpha and IL-1 beta treatment of these cells led to stimulation of DNA synthesis (as shown by increase of 3H-thymidine incorporation up to 35-fold) and also resulted in colony formation of leukemic megakaryoblasts. However, the stimulatory effect of IL-1 was dependent on endogenous production of IL-6, because addition of neutralizing monoclonal antibody (MoAb) to IL-6 abrogated the stimulatory activity of IL-1. In contrast, neutralizing MoAbs to granulocyte (G)-colony stimulating factor (CSF), granulocyte-macrophage (GM)-CSF, and macrophage (M)-CSF failed to counteract the growth-enhancing effects of IL-1. Leukemic megakaryoblasts accumulated IL-6 mRNA and released IL-6 protein into their culture supernatant when exposed to rh IL-1 but failed to disclose transcripts for G-, GM-, and M-CSF under these conditions. Analysis of IL-6 receptor (IL-6R) transcript levels demonstrated that megakaryoblasts constitutively expressed IL-6R mRNA and that these transcripts are down-regulated to undetectable levels upon exposure to IL-1 and IL-6. Increase of 3H-thymidine incorporation by megakaryoblasts could be duplicated by exogenous IL-6 that could be blocked by neutralizing MoAb to IL-6. In conclusion, our results suggest that leukemic megakaryoblasts could produce and secrete IL-6, and express IL-6R, and that the growth-enhancing effect of IL-1 on these cells is indirect, via production of IL-6 by leukemic cells.
Enlarged adenoid and adenoidectomy in adults: endoscopic approach and histopathological study. Adenoid enlargement is uncommon in adults and because examination of the nasopharynx by indirect posterior rhinoscopy is inadequate, many cases of enlarged adenoid in adults are misdiagnosed and accordingly maltreated. This study was conducted on 35 cases of enlarged adenoid aged between 20 and 42 years. The nasal endoscope was utilized to identify the adenoid mass. Adenoidectomy under transnasal endoscopic control was performed and all the excised material was sent for histopathological examination. Adenoidectomy resulted in marked improvement in 94 per cent of cases without major complications. Histopathological examination revealed non-specific inflammatory reaction in 15 cases (43 per cent), pure reactive changes, predominantly follicular hyperplasia, in two cases (6 per cent) and mixed pattern in 18 cases (51 per cent). Endoscopic follow-up for an average 17 months identified recurrence in only two patients. It was concluded that enlarged adenoid tissue in adults has some histopathological differences from that in children and adenoidectomy under transnasal endoscopic control is safe and reliable.
Neuroendocrine activity in congestive heart failure. The increased neuroendocrine activity in patients with congestive heart failure appears to be a generalized attempt to maintain blood pressure at the expense of reduced cardiac performance and salt and water retention. It is likely that baroreceptor dysfunction contributes to increased sympathetic nervous system activity in patients with congestive heart failure. The usual tonic inhibitory messages emanating from baro- and mechanoreceptors in the great vessels and heart fail to adjust sympathetic traffic from the brain to the periphery, leading to uninhibited sympathetic tone. Arginine vasopressin and plasma renin activity may be increased secondarily; however, plasma renin activity activation could also be induced by a low-salt diet and diuretic use. Preliminary baseline data indicate that patients with left ventricular dysfunction (ejection fraction less than or equal to 35%) but no or very mild symptoms of heart failure have increased plasma levels of norepinephrine, atrial natriuretic factor and arginine vasopressin, while plasma renin activity is normal, suggesting that neuroendocrine activity contributes to the pathogenesis of congestive heart failure. Neurohormones such as angiotensin II may alter gene expression, leading to changes in the shape and size of the cell. Remodeling of the heart and blood vessels is associated with both heart failure and hypertension. Angiotensin-converting enzyme inhibitors have been demonstrated to retard or reverse the remodeling process under certain experimental conditions. Studies are currently under way to test this possibility in patients.
Immune responses to allogeneic and xenogeneic implants of collagen and collagen derivatives. Whereas xenogeneic collagen has provided a safe and effective biomaterial for numerous medical applications, there are few instances in which data permit the correlation of the immunologic profile of well-defined devices with their clinical sequelae. A major exception is the use of injectable bovine dermal collagen for soft-tissue contour correction. The low incidence of hypersensitivity has been studied in the context of clinical efficacy and safety with several devices. The findings indicate that such immunity usually results in the manifestation of local symptoms of dermal inflammation at sites of treatment that resolve as the implant is resorbed by the host. In contrast, more immunogenic hemostatic agents may elicit a more frequent or vigorous immune response that is not clinically visible or relevant in that application. Recent experiences with collagen-based devices for the repair and regeneration of bone have also demonstrated that the presence of immunity to their collagenous or non-collagenous components does not necessarily predict adverse clinical sequelae. Indeed, numerous specific data indicate that this immunity can exist as an epiphenomenon with no effect on osteogenesis. To get a true composite picture of biocompatibility, significant steps must be taken to characterize biomaterials properly and to ensure that immunologic, clinical, histologic, and other pertinent laboratory data are viewed in relation to one another and not in isolation.
Hemorrhoidectomy during pregnancy: risk or relief? Acute hemorrhoidal crisis can occur in the pregnant female. When medical therapy fails to relieve pain, operative intervention may be necessary. The surgeon, however, may be reluctant to operate due to potential complications to the mother and fetus. From July 1983 to July 1989, hemorrhoidectomy was performed in 25 of 12,455 pregnant women (0.2 percent) who delivered in our institution. Twenty-two women were in their third trimester, 80 percent were multiparous, and each had a remote history of hemorrhoidal symptoms, including intermittent pain, bleeding, and protrusion. Closed hemorrhoidectomy was performed under local anesthesia. The surgery was directed at removing only symptomatic disease, which included three quadrants in 14 patients, two quadrants in seven patients, and one quadrant in four patients. All patients experienced relief of intractable pain the day after surgery, except one patient who required a hemostatic packing during the immediate post-operative period. There were no other maternal or fetal complications. Subsequent follow-up for anorectal disease ranged from 6 months to 6 years. Six (24 percent) patients required additional hemorrhoid treatment. Hemorrhoidectomy in selected pregnant patients is safe in our experience.
Anterior cervical discectomy and fusion. A retrospective review of 94 patients who had undergone anterior cervical discectomy and fusion was performed to analyze the result in patients who had a diagnosis of posterolateral spondylosis, disc herniation, or both. Although in 23 of 94 patients additional adjacent asymptomatic levels of spondylosis were noted, only the symptomatic levels were addressed in the 94 cases. Postoperatively two cases of dysphagia were noted, as well as a 4% pseudarthrosis rate. There was an 88% good or excellent result when no additional spondylosis was present, but only a 60% good or excellent result when just the symptomatic levels were addressed, leaving unoperated adjacent levels of spondylosis.
Sedation for upper gastrointestinal endoscopy: results of a nationwide survey. A postal questionnaire inquiring about routine sedation and premedication practice for upper gastrointestinal endoscopy was sent to 1048 doctors. Of 665 appropriate returns, 81% were from consultant physicians and surgeons. Most endoscopists (90%) reported using an intravenous benzodiazepine for at least three quarters of endoscopies and 54% of physicians and 69% of surgeons always did so. Midazolam was the intravenous sedative used by a third of all respondents and 13% also used an additional intravenous agent, usually pethidine. Over the previous two years a total of 119 respiratory arrests, 37 cardiac arrests, and 52 deaths were identified. Adverse outcomes were reported more frequently by consultant physicians, by those who 'titrated' the intravenous sedative, and by those who used an additional intravenous agent, but were reported equally frequently by endoscopists using midazolam and endoscopists using diazepam. There is an urgent need for a prospective study to identify the circumstances and risk factors associated with adverse outcomes related to endoscopy.
Noncoordinate regulation of alpha-1 adrenoreceptor coupling and reexpression of alpha skeletal actin in myocardial infarction-induced left ventricular failure in rats. To determine the effects of myocardial infarction-induced left ventricular failure on the regulation of surface alpha-1 adrenoreceptors and signal transduction, large infarcts were produced in rats and the animals killed seven days later. After the documentation of impaired left ventricular pump performance, radioligand binding studies of the alpha-1 adrenoreceptor, norepinephrine-stimulated phosphoinositol turnover, and ADP ribosylation of 41 kD substrate by pertussis toxin were examined in the hypertrophying unaffected myocardium. Moreover, the expression of sarcomeric actin isoforms was analyzed by Northern blots and hybridization with specific oligonucleotide probes. Alpha-1 adrenoreceptor density was found not to be altered in membranes obtained from the spared left ventricular tissue, whereas phosphoinositol turnover was increased 3.1-fold in the viable myocytes of infarcted hearts. Furthermore, pertussis toxin substrate was augmented 2.5-fold in membranes prepared from the surviving left ventricular myocardium. Finally, an upregulation of the skeletal actin isoform was detected in the tissue of the failing left ventricle. In conclusion, the possibility is raised that in the presence of severe myocardial dysfunction and ongoing reactive hypertrophy, effector pathways linked to the alpha-1 adrenoreceptor may stimulate the myocyte hypertrophic response which would tend to normalize cardiac hemodynamics. The reexpression of alpha skeletal actin may be a molecular indicator of the persistance of an overload on the myocardium.
Analysis of the Medtronic Intact bioprosthetic valve. Effects of "zero-pressure" fixation. The long-term performance of current-design porcine xenograft valves has not been satisfactory. These valves are generally fixed at "low pressures" of about 3 to 5 mm Hg. The Medtronic Intact (Medtronic, Inc., Minneapolis, Minn.) valve is fixed at "zero pressure" and is proposed as a better alternative to existing xenograft valves. A mechanical analysis of this valve has been carried out to determine if the Intact valve differs significantly from the low-pressure fixed xenograft. Twelve circumferential strips of tissue 5 mm wide were cut from the leaflets of four clinical-grade Intact valves. Their stress/strain, stress relaxation, and flexural behavior were examined mechanically and histologically. The Intact valve was more extensible than the low-pressure fixed xenograft (22% versus 12% strain, p less than 0.001), relaxed faster (p less than 0.001), and was more pliable than the xenograft (p less than 0.05). It did not, however, buckle less than did the low-pressure fixed xenograft during enforced bending, and it buckled significantly more than did fresh porcine aortic valve tissue (p less than 0.001). The Intact valve also relaxed significantly more slowly than did the fresh tissue (p less than 0.05). Its bending stiffness had a stronger dependence on leaflet thickness than the bending thickness of fresh tissue had (p less than 0.001) but a weaker dependence than the bending thickness of the low-pressure fixed xenograft material had (p less than 0.001). The Intact valve demonstrated a very large variability in extensibility, bending stiffness, and buckling behavior, with little correlation between these parameters. Some valves appeared to have wrinkled leaflets; others were likely fixed at different pressures. The shrinkage of the leaflet material at these low fixation pressures is likely important, since it can modify the elastic behavior of the valve cusps. Overall, the Intact valve had a more "natural" elastic behavior than had low-pressure fixed xenograft, and it should therefore experience lower stresses during normal valve function. It can be concluded that zero-pressure fixation does preserve many of the desirable stress-reducing properties of aortic valve tissue.
Left ventricular rupture complicating percutaneous mitral commissurotomy: salvage using percutaneous cardiopulmonary bypass support. Left ventricular rupture resulting in death has been reported to be a complication of percutaneous mitral commissurotomy. We report a 71-year-old man in whom a left ventricular rupture occurred during percutaneous mitral commissurotomy and resulted in hemodynamic collapse due to acute cardiac tamponade. The patient was stabilized using percutaneously instituted cardiopulmonary bypass support with subsequent repair of the left ventricle and successful mitral valve replacement. Three months later this patient remains in New York Heart Class I.
Magnetic resonance imaging for ineffectual tarsal tunnel surgical treatment. Tarsal tunnel syndrome (TTS) is an entrapment neuropathy caused by compression of the posterior tibial nerve beneath the ankle flexor retinaculum. Treatment of TTS consists of surgical release of the retinaculum. The failure rate is 10%-20%. Magnetic resonance (MR) imaging was used to evaluate a patient with an unsatisfactory response. MR imaging demonstrated incompleteness of the surgical release of the flexor retinaculum.