123rc/medical_text huggingface dataset:
Effect of hyperthermia in vitro and in vivo on adenine and pyridine nucleotide pools in human peripheral lymphocytes. Hyperthermia has been shown in vitro and in vivo to potentiate the effects of ionizing irradiation. Previous studies found that hyperthermia alters the metabolism of adenosine diphosphate (ADP)-ribose polymers required for recovery from DNA damage and that poly(ADP-ribose) polymerase activity is very sensitive to cellular nicotinamide-adenine dinucleotide (NAD) levels. Thus, the effect of 41.8 degrees C hyperthermia in vitro and in vivo on NAD and adenosine triphosphate (ATP) levels was studied in human peripheral lymphocytes. In vitro studies showed significant decreases in oxidized NAD (NAD+) and ATP levels after heating that simulated a clinical whole-body hyperthermia (WBH) treatment. This nucleotide depletion could not be attributed to nucleotide leakage or increased enzymatic NAD+ consumption. As the reduction of NAD observed was sufficient to decrease poly(ADP-ribose)polymerase activity by 50%, the studies were extended to clinica cases. Cellular NAD+ and ATP were measured in previously stored lymphocytes obtained from four patients before and after WBH; a statistically significant decrease in NAD+ was observed after WBH which quantitatively agreed with the in vitro results. Based on these results a prospective study was done in three patients; NAD+ was extracted immediately on sample collection, and the kinetics of WBH-induced NAD depletion were studied. These data, which agree quantitatively with the laboratory results, are presented.
Carbamazepine dose requirements during stiripentol therapy: influence of cytochrome P-450 inhibition by stiripentol. The inhibitory effect of stiripentol (STP) on disposition of carbamazepine (CBZ) and carbamazepine-10,11-epoxide (CBZE) was quantitated to establish CBZ dosage reduction guidelines for future clinical add-on efficacy trials of STP. In seven epileptic patients, STP (1,500-3,000 mg/day for 2 weeks) inhibited CBZ clearance by 50 +/- 16% (p = 0.001) and reduced the CBZE/CBZ plasma ratio by 45 +/- 14% (p = 0.0005). The inhibitory effect was gradually manifested over a period of 7-10 days after initiation of STP therapy. In contrast to inhibition of CBZE formation, STP had no effect (p greater than 0.05) on elimination clearance or half-life (t1/2) of CBZE in six healthy volunteers. STP most likely exerts inhibitory effects through inhibition of cytochrome P-450. This hypothesis was confirmed in the present study by the finding that a therapeutic concentration of STP (7 micrograms/mL) inhibited 10,11-epoxidation of CBZ in human liver microsomes by 40-50%. On the basis of results from this study, we propose that (a) CBZ dosage should be reduced in steps over a period of 7-10 days after initiation of STP, and (b) a CBZ dosage of 4.3 to 8.7 mg/kg/day will maintain therapeutic CBZ plasma levels of 5-10 micrograms/mL.
Immunochemical characterization and quantitative distribution of pancreatic stone protein in sera and pancreatic secretions in pancreatic disorders. A fluorometric immunoassay has been established to quantitate pancreatic stone protein providing a sensitivity for concentrations from 0.015 to 0.5 micrograms/mL. When concentrations of pancreatic stone protein were determined from pancreatic secretions obtained either from patients suffering from chronic pancreatitis (n = 31) [including the calcifying forms (n = 10)], pancreatic cancer (n = 22), or nonpancreatic diseases (n = 17), no significant differences were found. In contrast, increased concentrations were found in serum samples from patients with chronic (39/66) and acute pancreatitis (16/20) compared with control patients. The differences between these diagnostic groups and controls were highly significant (P less than 0.0001) and independent of pancreatic enzyme activity. Immunochemical analyses of serum pancreatic stone protein showed an isoelectric point (pH 9) similar to that reported for the pancreatic thread protein. With respect to recent communications, these data do not support the etiopathogenic role postulated for pancreatic stone protein in chronic pancreatitis and chronic calcifying pancreatitis by other investigators.
Twelve-year comparison of a Bjork-Shiley mechanical heart valve with porcine bioprostheses BACKGROUND. Patients undergoing heart-valve replacement may receive a mechanical prosthesis, necessitating lifelong anticoagulant treatment, or a porcine bioprosthesis, which involves no absolute need for anticoagulants. METHODS. We carried out a randomized, prospective trial to compare the durability of the Bjork-Shiley mechanical prosthesis (spherical tilting-disk model) and the incidence of valve-related complications with those variables in the Hancock and the Carpentier-Edwards porcine prostheses. The mitral valve was replaced in 261 patients, the aortic valve in 211, and both in 61; the survivors have been followed up for a mean of 12 years. RESULTS. We found a trend toward improved actuarial survival after 12 years with the Bjork-Shiley prosthesis, but this trend was not statistically significant (group with Bjork-Shiley valve vs. group with porcine valve [mean +/- SE], 51.5 +/- 3.2 vs. 44.4 +/- 3.2 percent; P = 0.08). There was no significant difference in the actuarial incidence of reoperation after 5 years, but after 12 years significantly more patients with a porcine prosthesis had undergone reoperation (8.5 +/- 2.0 vs. 37.1 +/- 4.1 percent, P less than 0.001). An analysis combining death and reoperation as end points for an actuarial assessment of survival with the original prosthesis intact confirmed that the patients with Bjork-Shiley Shiley prostheses had improved survival (48.6 +/- 3.2 vs. 30.0 +/- 3.0 percent after 12 years, P less than 0.001). Bleeding requiring hospitalization or blood transfusion was significantly more frequent in the patients with Bjork-Shiley prostheses (18.6 +/- 3.2 vs. 7.1 +/- 2.3 percent after 12 years, P less than 0.01). There was no significant difference after 12 years in the actuarial occurrence of embolism (Bjork-Shiley vs. porcine, 21.1 +/- 3.1 vs. 26.4 +/- 3.5 percent) or endocarditis (3.7 +/- 1.4 vs 4.6 +/- 1.6 percent). CONCLUSIONS. Survival with an intact valve is better among patients with the Bjork-Shiley spherical tilting-disk prosthesis than among patients with porcine bioprostheses, but use of the Bjork-Shiley valve carries an attendant increased risk of bleeding associated with the need for anticoagulant treatment.
Hemodynamic and endocrine effects of mental stress in untreated borderline hypertension. Mental arithmetic and mirror tracing were compared in 40 untreated patients with borderline hypertension, tested in random sequence in standardized protocols. Both tasks significantly increased systolic and diastolic blood pressure, heart rate, cardiac index, plasma renin, and decreased peripheral resistance. Mental arithmetic also increased cholesterol, triglycerides and HDL; plasma catecholamines were not changed significantly. Lipid changes were correlated with blood pressure changes. These methods will be useful in exploring the relationships between hemodynamic reactivity to stress, and the presence and progression of atherosclerosis, as well as testing the effects of antihypertensive drugs on stress-induced changes that may influence atherosclerotic complications of hypertension.
Cutaneous angiolipoleiomyoma. We describe eight cases of cutaneous angiolipoleiomyoma, a rare tumor previously reported only once under the term cutaneous angiomyolipoma. Clinically, the tumors were acquired, solitary, asymptomatic nodules that were always acral in location. Patients' ages ranged from 33 to 77 years (median 52.6 years); the male/female ratio was 7:1. Signs of tuberous sclerosis or renal angiomyolipoma were absent in all cases. Histologically, the tumors were subcutaneous, well circumscribed, and composed of smooth muscle, vascular spaces, connective tissue, and mature fat. In some tumors the fat was the predominant component, and in others smooth muscle predominated. Elastic tissue stains revealed that some blood vessels had developed an elastic lamina whereas other blood vessels lacked it. Additional histologic features occasionally observed included vascular thrombi, glomus bodies, and focal mucin deposition.
Colonoscopic screening of asymptomatic patients with a family history of colon cancer. The records of 201 asymptomatic patients who underwent colonoscopy based solely on a family history of colon cancer were reviewed. Eighty-five patients (42 percent) had a total of 166 lesions. Fifty-four (27 percent) patients of the screened population had neoplastic lesions, while 31 (15 percent) patients had nonneoplastic polyps. Four carcinomas were found. Twenty-five of the patients with polyps (29 percent) had no polyps distal to the splenic flexure; these proximal polyps (and two carcinomas) would have been missed on screening with fiberoptic sigmoidoscopy. Nineteen of these 25 patients had polyps smaller than 0.5 cm, which likely would have been missed with contrast enemas. Almost one half (47 percent) of all polyps discovered at screening colonoscopy were proximal to the descending colon. Only one patient younger than 40 years old had adenomas. The yield of polyps and cancer in patients with familial risk indicates screening colonoscopy should be considered after age 40.
MRI findings in neuro-Behcet's disease. We report MRI findings in 6 patients with Behcet's disease and CNS involvement. There were 3 different stages of imaging appearance: (1) During the acute illness, there were scattered areas of high signal intensity on T2-weighted images with predilection to the central structures of the cerebrum, the cerebral peduncles, and basis pontis. (2) During the recovery phase, most of these findings improved, but some white matter high signal areas persisted in the upper brainstem and peripheral subcortical white matter. Occasionally, findings were suggestive of microhematoma. (3) During the chronic phase, atrophy of posterior fossa structures became evident with decreased signal intensity suggestive of hemosiderin deposits.
Increased extravascular lung water in patients with low pulmonary artery occlusion pressure after acute myocardial infarction. OBJECTIVE: To evaluate the clinical characteristics of increased extravascular lung water (EVLW) in patients with low pulmonary artery occlusion pressure (PAOP) in the early phase of acute myocardial infarction. DESIGN: Consecutive sample for descriptions of the clinical features of medical disorders. SETTING: A general medicine group practice in a university hospital. PATIENTS: Sixteen patients with low PAOP (less than 18 mm Hg) on the initial measurement obtained within 12 hr of chest pain onset. MEASUREMENTS AND MAIN RESULTS: EVLW was measured by the thermal indocyanine green dye double-indicator dilution method. QRS score was obtained on hospital day 7 from the Selvester's QRS Scoring System. Eleven (69%) patients had increased EVLW greater than 7 mL/kg despite low PAOP. EVLW had no significant correlation with PAOP and the difference between plasma colloid osmotic pressure and PAOP, but did have a significant correlation with pulmonary vascular resistance index (r2 = .31, p less than .05), and QRS score (r2 = .45, p less than .005). CONCLUSIONS: Larger infarcts led to increased EVLW even with low PAOP, and the accumulation of increased EVLW around the small arterioles might have led to increased pulmonary vascular resistance.
Human leukoagglutinating antibody evokes cooperative leukotriene synthesis in pulmonary microvasculature. Model of transfusion-related acute lung injury. Leukoagglutinating antibodies have been implicated in the development of transfusion-related acute lung injury. In the present study, human neutrophil leukotriene generation was provoked by an anti-5b immunoglobulin G, isolated from a multiparous donor plasma that caused noncardiogenic lung edema during transfusion therapy. In 5b-positive polymorphonuclear neutrophils (PMNs), the antibody stimulated marked arachidonic acid metabolism, dependent on the presence of plasma as the complement source. Quantity and profile of lipid mediators (leukotriene B4 and its omega-oxidation products, 5-hydroxyeicosatetraenoic acid, and nonenzymatic hydrolysis products of leukotriene A4) corresponded to those repeatedly described after PMN in vitro stimulation with the artificial calcium ionophore A23187. Anti-5b challenge of PMNs sequestered in the microvasculature of perfused rabbit lungs did, however, induce a markedly modified metabolite profile. Nonenzymatic hydrolysis products of leukotriene A4 were not detected, and 5-hydroxyeicosatetraenoic acid was markedly reduced. In contrast, cysteinyl leukotrienes were measured as predominant compounds, with rapid appearance of leukotriene C4 and more protracted generation of leukotriene E4. Leukotriene B4 and its omega-oxidation products were released with similar kinetics, but in lower amounts, as compared with the isolated PMN stimulation. Anti-5b challenge of PMNs coincubated with pulmonary artery endothelial cells in vitro, but not stimulation of either cell type alone, provoked marked generation of cysteinyl leukotrienes. These findings suggest modulation of PMN 5-lipoxygenase metabolism in favor of leukotriene A4 transfer to adjacent acceptor cells with subsequent enzymatic conversion to cysteinyl leukotrienes under conditions of lung vascular sequestration. Endothelial cells appear to serve as predominant cooperative cells under circumstances of blood-free lung perfusion. PMN-related transcellular eicosanoid synthesis may be involved in the pathogenesis of transfusion-evoked acute lung injury.
Reconstruction of mandibular defects in irradiated patients. In this prospective study, mandibular reconstruction using titanium plates was evaluated in 31 patients treated between July 1988 and January 1990. Sixteen patients had prior surgery; 13 had prior radiotherapy. In 11 patients, prior radiation and surgery had failed. Sixteen patients received postoperative radiotherapy either in standard or accelerated fractions. Twelve patients had complications of either intraoral (8), extraoral (5), or combined (1) plate exposure or fistula formation (2). Factors significantly related to complications were poor nutrition, accelerated radiation, and recurrence. Sixty-one percent of all patients healed uneventfully. When patients with complications secondary to recurrence who subsequently died were excluded, the success rate was 73%. Only one patient had an unacceptable result that produced a cosmetic and functional deformity despite secondary repair.
Induction of in vitro graft-versus-leukemia activity following bone marrow transplantation for chronic myeloid leukemia. We studied the in vitro effects of lymphokine-activated killer (LAK) cells from the peripheral blood of chronic myeloid leukemia (CML) patients after allogeneic and syngeneic bone marrow transplantation (BMT). LAK cells were generated by incubating peripheral blood mononuclear cells from patients post-BMT with recombinant interleukin-2 (IL-2) (500 U/mL) in 10% AB serum for 7 days. They were phenotyped and tested for activity in a standard 4-hour 51Cr release assay (n = 37) and in a CFU-GM assay (n = 24). We found that the LAK cells were mainly activated natural killer cells, but some were CD3+ T cells. In the 51Cr release assay LAK cells from 20 of 33 (61%) allogeneic and 2 of 4 syngeneic recipients killed recipient CML cells and in 22 of 37 (60%) cases also killed the HLA disparate CML cells. In the CFU-GM assay the LAK cells incubated together with the CML cells in liquid culture before plating inhibited (P less than .05) colony growth in 16 of 22 allogeneic and 2 of 2 syngeneic recipients. Cell-cell contact was necessary for optimal effect. There was little or no inhibition of proliferation of donor marrow CFU-GM. This in vitro graft-versus-leukemia (GVL) effect could also be demonstrated after LAK effectors were depleted of CD3+ T cells. It was inducible in recipients of both T cell-depleted and T cell-replete donor marrow and in recipients with or without graft-versus-host disease. These results suggest that a major histocompatibility complex-unrestricted GVL effect is inducible following allogeneic and syngeneic BMT. The use of IL-2/LAK cells after BMT could reduce the risk of relapse.
Experience with in situ saphenous vein bypasses during 1981 to 1989: determinant factors of long-term patency. From 1981 to 1989, 361 consecutive in situ saphenous vein bypasses were performed. Indications for revascularization were critical limb ischemia (n = 335, 93%), popliteal aneurysm (n = 15, 4%), and claudication (n = 11, 3%). Outflow tract was the popliteal artery in 116 (32%) and tibial artery in 245 (68%) of bypasses. At 6 years primary patency was 63% and secondary patency was 81%. During the performance of the in situ bypass procedure, 86 (24%) venous conduits were modified because of a technical failure (n = 49, 13%) or an inadequate vein segment (n = 37, 10%). Secondary patency at 4 years for bypasses requiring modification was 72% compared to 84% for bypasses not modified (p less than 0.05). Atherosclerotic disease of the inflow artery necessitating endarterectomy, patch angioplasty, or replacement lowered primary patency at 3 years (69%) compared to the inflow artery not requiring reconstruction (46%, p less than 0.02). In the follow-up period, 95 (26%) bypasses were revised because of thrombosis or hemodynamic failure. Bypasses requiring revision had a 4-year secondary patency of 68% compared to 88% for bypasses not revised (p less than 0.02). The first 179 cases (1981 to 1985) were compared to the subsequent 182 cases (1986 to 1989). The secondary patency at 3 years for the latter half (92%) compared to the first half (80%) of the experience was significantly improved (p less than 0.02). The secondary patency for bypasses not requiring revision was significantly improved (p less than 0.02) for the latter half (n = 142, 97%) compared to the first half (n = 124, 83%) of the series. Long-term patency with the in situ saphenous vein bypass is dependent on surgical experience, quality of the venous conduit, and atherosclerotic disease of the inflow artery that necessitates reconstruction. Meticulous surgical technique and compulsive bypass surveillance results in superior long-term patency.
Reoperation for small intestinal obstruction. Today, intestinal adhesions represent the most frequent etiology for complete or partial intestinal obstruction. Although partial obstruction can be treated nonoperatively with a considerable likelihood of success, intestinal strangulation cannot uniformly be predicted or prevented. Complete intestinal obstruction is associated with a significant incidence of strangulation if not treated by a vigorous surgical approach. Consequently, complete intestinal obstruction secondary to adhesions is still a surgical disease. Attempts at control of the adhesion process include mechanical methods to prevent subsequent obstruction and chemical methods to prevent the adhesion process itself. The invasive mechanical methods appear dated. A variety of agents have been used either systemically or in the peritoneal cavity to prevent the establishment of intra-abdominal adhesions. Agents that do not contribute to subsequent morbidity or impede the native host defense mechanisms should be utilized. High-molecular-weight dextran and nonsteroidal anti-inflammatory agents show some promise of being both safe and effective. As is frequently the case, the bottom line in preventing and treating intra-abdominal adhesions is appropriate surgical technique. Intestinal adhesions can be related clearly to leaving damaged, devitalized, or ischemic tissue in the peritoneal cavity or to excessive roughness in handling of tissues. Steps such as avoidance of excessive suture material and unnecessary handling of the bowel will do much to prevent subsequent adhesion generation. Likewise, the surgical lysis of intraperitoneal adhesions is frequently fraught with complications such as intra-abdominal abscess or postoperative incisional failure. This is again related to surgical technique and most directly to the use of blunt dissection to divide adhesions. Knife dissection in the lysis of adhesions is recommended. This technique, combined with excellent intraoperative hemostasis, can be associated with a marked diminution in the incidence of postoperative fistulas and abscesses.
From disease to delirium: managing the declining elderly patient. Many geriatric patients have concurrent physical and psychiatric illnesses, but at times it may be difficult to determine which is primary. Delirium, a transient syndrome that presents with psychiatric symptoms, is usually the manifestation of an organic disorder and, if undetected and untreated, can be fatal. Clinicians, therefore, must learn to recognize the syndrome, search diligently for the underlying etiology, and treat accordingly.
Use of the metabolic tracer carbon-11-acetate for evaluation of regional myocardial perfusion. The high first-pass myocardial extraction fraction of carbon-11-acetate suggests that its initial uptake depends on blood flow. Accordingly, regional uptake of 11C-acetate at 4 min was compared to regional perfusion determined with nitrogen-13-ammonia in 119 segments in 15 patients with stable coronary artery disease by two methods. A close correlation was observed between initial relative myocardial concentrations (segmental activity normalized to maximal activity) of both tracers (11C-acetate = 0.88; 13N-ammonia + 0.079; s.e.e. = 0.064, r = 0.94, p less than 0.001). Furthermore, segmental net extractions (E.F), as calculated from the input function and segmental activities, of the two tracers correlated closely by E.FC-11 = 0.55E.FN-13 + 0.080 (s.e.e. = 0.045, r = 0.87, p less than 0.001). These relationships indicate that initial regional myocardial uptake of 11C-acetate reflects perfusion and that 11C-acetate permits near simultaneous evaluation of regional oxidative metabolism and of regional myocardial perfusion.
Parascapular free flaps for head and neck reconstruction. We report our experience with single-stage, primary reconstruction of the head and neck in 29 consecutive patients using parascapular free flaps. The commonest indications were for craniofacial defects (9), oropharyngeal soft tissue defects (10), and combined mandibular and soft tissue losses (4). Ablative surgery was performed for squamous carcinoma (22), melanoma (2), and malignant fibrous histiocytoma (2). Seven patients died of recurrent disease during a 3 1/2 year follow-up. Seven patients are alive with recurrence. Flap complications included total loss (2) due to unsalvageable microvascular thrombosis, wound breakdown with oropharyngeal fistula (2), mandibular osteomyelitis (1), trismus (2), neck contracture (1), and donor site wound dehiscence (1). The overall success of this reconstruction was 93%. Primary wound healing was the general rule with lower morbidity than with other reconstructive techniques. The flap is thin, pliable, and conforms well to three-dimensional defects. The lateral border of the scapula can be incorporated on the same vascular pedicle for single-stage mandibular reconstruction. No muscle is sacrificed, and the posterior donor defect is an added advantage. The parascapular flap is our first choice for reconstruction of major defects in the head and neck.
Reciprocal inhibition between forearm muscles in spastic hemiplegia. We studied reciprocal inhibition of H-reflexes in the forearm flexor and extensor muscles in 14 patients with spastic hemiplegia secondary to a focal cerebral lesion and 14 normal volunteers. In the spastic limb, the Hmax/Mmax ratio was increased in both flexor and particularly extensor wrist muscles. The 3 normal inhibitory phases of reciprocal inhibition between extensor and flexor forearm muscles were markedly reduced on the spastic side of patients. The early disynaptic phase showed the greatest alteration. Reduced or absent inhibition between forearm muscles associated with increased spinal motoneuron excitability may be typical to spastic hemiplegia.