Successful autologous peripheral blood stem cell harvest and transplant in a patient with cold agglutinins.
Explore the source record for details and available documents.
Antineoplastic Combined Chemotherapy Protocols↗
Biomedical subjects
D Collins
Publications and source records attributed to D Collins.
EUS-guided celiac block and neurolysis.
Abdominal pain related to pancreatic cancer or chronic pancreatitis can be a disabling and difficult symptom to treat for patients, their families, and physicians. Pharmacologic therapy with nonsteroidal anti-inflammatory drugs is usually ineffective. Opiate analgesics may not be well tolerated and can lead to dependence. Endoscopic ultrasound-guided celiac plexus block offers a potential adjunct treatment for pain control.
Celiac Plexus↗
Comparison of questionnaire and quantitative ultrasound techniques as screening tools for DXA.
The aim of the study is to assess the sensitivity and specificity of different techniques and their ability to act as screening tools in relation to dual energy X-ray absorptiometry (DXA) in a group of 208 postmenopausal women. In this study we examined eight screening systems for the diagnosis of osteoporosis, the osteoporosis self-assessment tool (OST), the osteoporosis risk assessment instrument (ORAI), the osteoporosis index of risk (OSIRIS), a risk index derived using data from the study of osteoporotic fractures (SOFSURF), the simple calculated osteoporosis risk estimation (SCORE), patient body weight (pBW), along with two ultrasound based systems, the Sunlight Omnisense (Sunlight Medical, Rehovot, Israel) and the CUBA Clinical (McCue plc, Winchester, UK). The sensitivity and specificity of the different techniques in relation to DXA were plotted as receiver-operating characteristic (ROC) curves at three different levels (DXA T-score -2.5 osteoporosis, -2 and -1 osteopenia). The areas under the curves (AUC) were calculated and showed broadband ultrasound attenuation (BUA) at the calcaneus to provide consistently the highest AUC (0.77-0.81). The velocity of sound (VOS) of the calcaneus (AUC=0.72-0.76) was equally good, but was out-performed by some of the questionnaire systems (AUC=0.66-0.79). Both the questionnaire systems and the CUBA Clinical out-perform the Sunlight Omnisense (AUC=0.58-0.7), which showed comparable performance with body weight (AUC=0.66-0.69). The results show that QUS is capable of selecting patients with low bone density as measured by DXA. A patient displaying a low QUS value should be followed up with a DXA scan to confirm the diagnosis.
Absorptiometry, Photon↗
The ability of peripheral quantitative ultrasound to identify patients with low bone mineral density in the hip or spine.
This study aims to assess the sensitivity and specificity of two commercially available quantitative ultrasound (QUS) scanners (CUBA Clinical, Sunlight Omnisense), to differentiate patients with osteoporosis (OP) or osteopenia at the spine and hip confirmed by dual-energy x-ray absorptiometry (DXA) and to investigate the optimum cut-off values to maximize the effectiveness of the screening technique. Participants (n = 268) received DXA scans on their lumbar spine (L1-L4) and hip, with paired QUS scans on their distal radius, proximal phalanx, midshaft tibia and calcaneus. Scanners were evaluated by using receiver-operating characteristics curves and their area under the curve (AUC) values. Measurement of the calcaneus by the CUBA Clinical showed a superior ability to predict DXA, with AUC values between 0.75 to 0.83 in comparison with AUC values of 0.60 to 0.70 for the Sunlight Omnisense. Cut-off values varied according to the technique used and the accuracy of the screening required. Assessment of the calcaneus was the best QUS technique for the prediction of low bone density at the axial skeleton as diagnosed by DXA.
Absorptiometry, Photon↗
Long distance quantum teleportation in a quantum relay configuration.
A long distance quantum teleportation experiment with a fiber-delayed Bell state measurement (BSM) is reported. The source creating the qubits to be teleported and the source creating the necessary entangled state are connected to the beam splitter realizing the BSM by two 2 km long optical fibers. In addition, the teleported qubits are analyzed after 2.2 km of optical fiber, in another laboratory separated by 55 m. Time-bin qubits carried by photons at 1310 nm are teleported onto photons at 1550 nm. The fidelity is of 77%, above the maximal value obtainable without entanglement. This is the first realization of an elementary quantum relay over significant distances, which will allow an increase in the range of quantum communication and quantum key distribution.
Journal Article↗
Aetiology and management of acute cardiac tamponade.
OBJECTIVE: To review current concepts in the aetiology and management of patients with cardiac tamponade. DATA SOURCES: A review of articles reported on acute cardiac tamponade. SUMMARY OF REVIEW: Cardiac tamponade is defined as a haemodynamically significant cardiac compression caused by pericardial fluid. The fluid may be blood, pus, effusion (transudate or exudate) or air and treatment involves correction of the cardiac diastolic restriction by removing pericardial fluid during either pericardiocentesis or thoracotomy. Pericardiocentesis is usually performed for urgent management of an acute tamponade. A thoracotomy is required when a tamponade exists following coronary artery bypass grafting, cardiac rupture, penetrating or closed cardiac trauma and aortic dissection or where a pericardial clot is likely. Removal of pericardial fluid by percutaneous catheterisation of the pericardial sac traditionally uses the subxiphoid 'blind' approach., However, pericardial aspiration is often currently performed under transthoracic echocardiographic guidance with the commonest site of needle entry being on the chest wall at or near the apex and the needle directed perpendicular to the skin. The pericardial fluid is drained using an indwelling 'pigtail' catheter, preferably with close monitoring of the pulmonary artery wedge pressure, as rapid removal of large volumes of pericardial fluid (> 500 mL) may result in a 'decompressive syndrome' causing pulmonary oedema. The fluid is sent for culture and Gram-stain and analysed for glucose, protein, lactate dehydrogenase, haemoglobin and white cell count. If appropriate the fluid is also analysed for amylase, and cholesterol and sent for cytology, serology and parasitic studies and viral, mycobacterial and fungal cultures. CONCLUSIONS: Cardiac tamponade may present as an acute or subacute syndrome of elevated central venous pressure and hypotension. Pericardiocentesis using echocardiographic guidance and right heart catheter control is often the method of choice for acute removal of fluid.
Journal Article↗
A rare case of intravascular lymphoma diagnosed on bone marrow trephine.
Intravascular lymphoma (IVL) is an extremely rare form of extra-nodal non-Hodgkins lymphoma characterised by the proliferation of neoplastic lymphocytes within the lumina of small arteries, veins and capillaries. The great majority of reported cases appear to be of B cell lineage. There is a wide variation in clinical presentation, and multiple organs are usually affected. We report a case of a 67-year-old man who presented with constitutional symptoms and neurological deficit and was diagnosed following bone-marrow trephine. His disease responded to polychemotherapy treatment but he died 15 months after diagnosis. This case in unusual in that it is generally felt that bone marrow is relatively spared until late in the disease and is often not clearly demonstrable histologically. In addition, this case supports the limited data that responses can be obtained following polychemotherapy treatment, although the prognosis remains generally poor.
Aged↗
Effect of MPC-11 myeloma and MPC-11 + IL-1 receptor antagonist treatment on mouse bone properties.
This study examines the effects of an IL-6-producing murine multiple myeloma cell line on trabecular and cortical mouse bone, and evaluates the efficacy of interleukin-1 receptor antagonist (IL-1ra) in mitigating bone destruction. Six-week-old BALB/c mice were assigned to two groups: normal controls and myeloma animals (5 x 10(7) MPC-11 cells on day 0). Myeloma animals were further assigned to three unique groups: MPC-11 only; MPC-11 treated with hyaluronic acid (HA); and MPC-11 + IL-1ra/HA (100 mg/kg). Disease development was assessed at 14 and 21 days via spleen, liver, and proximal tibia histology; histomorphometry at the femoral middiaphysis; and long bone composition and mechanical testing. Histologic analysis revealed marked myeloma infiltration into organs and bone marrow and gross bone resorption of the proximal tibia. IL-1ra tended to decrease bone resorption at the proximal tibia; however, it had no effect on quantitatively measured bone parameters. Whole femur and tibia, and tibial epiphysis, percent mineralization was decreased (3.0%, 2.9%, and 6.3%, respectively) in all MPC-11 groups. The presence of myeloma did not affect long bone stiffness, strength, or length over the 3 week study. The percent of the femoral endosteal perimeter showing excessive resorption ( approximately 60%) in the MPC-11 groups increased significantly after 21 days. MPC-11 cell presence caused no change in bone formation or morphology. Normal growth mechanisms were not impacted, as the bones lengthened and increased in size and mass despite the presence of myeloma. IL-1 does not appear to be a primary factor in in vivo bone destruction caused by the MPC-11 cell line. These findings reveal the stochastic nature of bone lesions in multiple myeloma and suggest that IL-1 is not a cytokine critical to this disease pathology.
Animals↗
Reduction in stroke with gemfibrozil in men with coronary heart disease and low HDL cholesterol: The Veterans Affairs HDL Intervention Trial (VA-HIT).
BACKGROUND: A low level of HDL cholesterol has been identified as a risk factor for stroke in observational studies. METHODS AND RESULTS: Our objective was to determine whether treatment aimed at raising HDL cholesterol and lowering triglycerides reduces stroke in men with coronary heart disease and low levels of both HDL and LDL cholesterol. The study was a placebo-controlled, randomized trial conducted in 20 Veterans Affairs medical centers. A total of 2531 men with coronary heart disease, with mean HDL cholesterol 0.82 mmol/L (31.5 mg/dL) and mean LDL cholesterol 2.9 mmol/L (111 mg/dL), were randomized to gemfibrozil 1200 mg/d or placebo and were followed up for 5 years. Strokes were confirmed by a blinded adjudication committee. Relative risks were derived from Cox proportional hazards models. There were 134 confirmed strokes, 90% of which were ischemic. Seventy-six occurred in the placebo group (9 fatal) and 58 in the gemfibrozil group (3 fatal), for a relative risk reduction, adjusted for baseline variables, of 31% (95% CI, 2% to 52%, P=0.036). The reduction in risk was evident after 6 to 12 months. Patients with baseline HDL cholesterol below the median may have been more likely to benefit from treatment than those with higher HDL cholesterol. CONCLUSIONS: In men with coronary heart disease, low HDL cholesterol, and low LDL cholesterol, gemfibrozil reduces stroke incidence.
Aged↗
Relation of gemfibrozil treatment and lipid levels with major coronary events: VA-HIT: a randomized controlled trial.
CONTEXT: A low plasma level of high-density lipoprotein cholesterol (HDL-C) is a major risk factor for coronary heart disease (CHD). A secondary prevention study, the Veterans Affairs High-Density Lipoprotein Intervention Trial (VA-HIT), demonstrated that CHD events were significantly reduced during a median follow-up of 5.1 years by treating patients with the fibric acid derivative gemfibrozil when the predominant lipid abnormality was low HDL-C. OBJECTIVE: To determine if the reduction in major CHD events with gemfibrozil in VA-HIT could be attributed to changes in major plasma lipid levels. DESIGN: Multicenter, randomized, double-blind, placebo-controlled trial conducted from September 1991 to August 1998. SETTING: The Department of Veterans Affairs Cooperative Studies Program, in which 20 VA medical centers were participating sites. PARTICIPANTS: A total of 2531 men with a history of CHD who had low HDL-C levels (mean, 32 mg/dL [0.83 mmol/L] ) and low low-density lipoprotein cholesterol (LDL-C) levels (mean, 111 mg/dL [2.88 mmol/L]). INTERVENTION: Participants were randomly assigned to receive gemfibrozil, 1200 mg/d (n = 1264), or matching placebo (n = 1267). MAIN OUTCOME MEASURE: Relation of lipid levels at baseline and averaged during the first 18 months of gemfibrozil treatment with the combined incidence of nonfatal myocardial infarction and CHD death. RESULTS: Concentrations of HDL-C were inversely related to CHD events. Multivariable Cox proportional hazards analysis showed that CHD events were reduced by 11% with gemfibrozil for every 5-mg/dL (0.13-mmol/L) increase in HDL-C (P =.02). Events were reduced even further with gemfibrozil beyond that explained by increases in HDL-C values, particularly in the second through fourth quintiles of HDL-C values during treatment. During gemfibrozil treatment, only the increase in HDL-C significantly predicted a lower risk of CHD events; by multivariable analysis, neither triglyceride nor LDL-C levels at baseline or during the trial predicted CHD events. CONCLUSIONS: Concentrations of HDL-C achieved with gemfibrozil treatment predicted a significant reduction in CHD events in patients with low HDL-C levels. However, the change in HDL-C levels only partially explained the beneficial effect of gemfibrozil.
Cholesterol, HDL↗
Common variants in the gene encoding ATP-binding cassette transporter 1 in men with low HDL cholesterol levels and coronary heart disease.
HDL cholesterol (HDL-C) deficiency is the most common lipid abnormality observed in patients with premature coronary heart disease (CHD). Recently, our laboratory and others demonstrated that mutations in the ATP-binding cassette transporter 1 (ABCA1) gene are responsible for Tangier disease, a rare genetic disorder characterized by severely diminished plasma HDL-C concentrations and a predisposition for CHD. To address the question of whether common variants within the coding sequence of ABCA1 may affect plasma HDL-C levels and CHD risk in the general population, we determined the frequencies of three common ABCA1 variants (G596A, A2589G and G3456C) in men participating in the Veterans Affairs Cooperative HDL Cholesterol Intervention Trial (VA-HIT), a study designed to examine the benefits of HDL raising in men having low HDL-C (< or =40 mg/dl) and established CHD, as well as in CHD-free men from the Framingham Offspring Study (FOS). Allele frequencies (%) in VA-HIT were 31, 16, and 4 for the G596A, A2589G, and G3456C variants, respectively, versus 27, 12, and 2 in FOS (P<0.03). None of the variants were significantly associated with plasma HDL-C concentrations in either population; however, in VA-HIT, the G3456C variant was associated with a significantly increased risk for CHD end points, suggesting a role for this variant in the premature CHD observed in this population.
ATP Binding Cassette Transporter 1↗
The effect of season and vitamin D supplementation on bone mineral density in healthy women: a double-masked crossover study.
Vitamin D status is known to be an important determinant of bone mineral density (BMD). There is a significant seasonal variation in serum vitamin D, and some studies have reported an associated seasonal variation in BMD. The present study was devised to investigate whether a seasonal variation in BMD could be detected in healthy normal subjects, along with associated variations in serum parathyroid hormone (PTH), intestinal calcium absorption and biochemical markers of bone turnover. A second aim was to investigate whether, if such variations were identified, they could be suppressed by vitamin D supplementation. The subjects were 70 healthy female volunteers (mean age 47.2 years, range 24-70 years) recruited into a double-masked crossover study and followed over 2 years. During the first year 35 subjects received a daily oral supplement containing 800 IU (20 micrograms) cholecalciferol (group 1) and 35 subjects received a placebo preparation (group 2). During the second year the treatment each group received was reversed. Lumbar spine (L1-L4), left proximal femur and total body BMD were measured by DXA at 3-month intervals. Serum 25-hydroxyvitamin D (25-OHD), serum PTH, bone markers (bone-specific ALP (BSAP) and urinary crosslinks (DYPD/creatinine)) and calcium absorption were also measured at each visit. Cholecalciferol treatment increased serum 25-OHD by 25.4 nmol/l (p < 0.001), while a reciprocal decrease in serum PTH of 6.6 ng/l (p = 0.011) was seen in subjects in the lowest quartile of baseline serum 25-OHD. The treatment had no significant effect on spine, femur or total body BMD, calcium absorption or bone markers. When Fourier analysis was used to analyze the data for seasonal effect (defined as twice the amplitude of the 1-year period variation) a highly significant effect for 25-OHD of 18 nmol/l (p < 0.001) was found. However, no effect was found for BMD, PTH, calcium absorption or bone markers. The analysis set a 95% confidence limit to the seasonal effect of less than 0.6% for spine, total hip and total body BMD. It was concluded that in the population of healthy women studied there was no evidence of seasonal variation in spine, femur or total body BMD, serum PTH, calcium absorption or bone markers. Vitamin D supplementation was found to have no effect on BMD.
Adult↗
Pre-shot EEG alpha-power reactivity during expert air-pistol shooting: a comparison of best and worst shots.
The aim of this study was to examine the proposal that pre-shot occipital electroencephalogram (EEG) alpha-power reactivity would not only associate with, but also have a causal role in, the relative success of performance outcome in expert air-pistol shooting. Six expert air-pistol shooters performed a sixty-shot match, individually, while electroencephalograms were captured from occipital and anterior-temporal electrode sites during the aiming period (3 x 2 s epochs) before shot release. The five best shots and five worst shots were selected for each shooter on the basis of four shot quality indicators, and pre-shot EEG alpha power for best shots was compared with that of worst shots. Occipital EEG alpha power was found to increase during epochs 1-3 before best shots, but to decrease before worst shots; it was significantly greater during the final pre-shot epoch of best shots. This finding suggests that visual attention to the pistol and target was gradually suppressed during the pre-shot period of best shots, whereas it gradually increased before worst shots. In addition, significantly greater EEG alpha power was found at the left than at the right anterior-temporal site, lending support to the robust findings of previous target-sport studies. We conclude that the participants were able to shoot at the target with greatest success when not having maximal visual attention on where the pistol was aimed and that suppression of visual attention during the final seconds of the pre-shot period is a necessary prerequisite for automatic shot execution, as controlled by mechanisms of intention.
Adult↗
Rating of perceived exertion during high-intensity treadmill running.
PURPOSE: The purpose of this investigation was 1) to evaluate the time course of the rating of perceived exertion (RPE; 6-20 Borg scale) during short-term, high-intensity, constant-load running (ST); and 2) to determine the reproducibility of RPE during ST. METHODS: Fifteen well-trained males (VO2max = 58.0 +/- 4.6 mL x kg(-1) x min(-1), mean +/- SD) performed treadmill running (i.e., between 3 and 4 m.s-1 at 10.5% incline) to volitional exhaustion (Tlim) at an exercise intensity equivalent to 125% VO2max. A total of four RPE measurements were taken during each test, one every 30 s during the first 120 s of the exercise. The tests were repeated at the same time of day on three occasions within a 3-wk period. RESULTS: Tlim for the three tests was 197.6 +/- 34.8 s. RPE was linearly related with exercise time (mean +/- SD for the three tests: RPE at 30 s = 10.8 +/- 2.2; RPE at 60 s = 12.6 +/- 1.8; RPE at 90 s = 14.5 +/- 1.7; RPE at 120 s = 16.0 +/- 1.9; RPE = 9.06 + (0.06 x time (s)); r = 0.71, SEE = 2.0, P < 0.01). Repeated ANOVA revealed no systematic bias between the three tests for RPE, and other measures of reliability were also favorable. These included intraclass correlation coefficients ranging from 0.78 to 0.87 and sample coefficients of variation of between 4.4% and 6.0%. The 95% limits of agreement ranged between 0.0 +/- 2.3 and 0.0 +/- 2.5. CONCLUSION: ST RPE displays a positive linear response during the first 2 min. The measurement of ST RPE appears to be reliable and could thus add a new dimension to ST investigations.
Adult↗
Acute gastrointestinal bleeding: Part I.
OBJECTIVE: To review the management of acute gastrointestinal bleeding in the critically ill patient in a two part presentation. DATA SOURCES: Articles and a review of studies reported from 1991 to 2001 and identified through a MEDLINE search of the English language literature on acute gastrointestinal bleeding. SUMMARY OF REVIEW: Gastrointestinal bleeding is a relatively frequent problem in the critically ill patient. Common causes include acute stress ulceration (ASU), peptic ulceration and bleeding oesophageal varices. Non-variceal upper gastrointestinal bleeding requires resuscitation and correction of coagulation disturbances before endoscopy is performed. If a bleeding ulcer is detected it is often managed by an adrenaline injection or electrocautery into the base of the lesion and a proton pump inhibitor (e.g. omeprazole 80 mg i.v. followed by 8 mg/hr for 72 hr then 20 mg orally for 8 weeks). Surgery is considered for all patients in whom bleeding persists despite endoscopic or medical therapy. While H(2) receptor antagonists have been used for the management of ASU, proton pump inhibitors are currently prescribed due to their greater gastric acid suppressant effect (e.g. omeprazole 40 mg i.v. daily for ASU prophylaxis, 40 mg daily or 12-hourly for ASU with mild blood loss and 80 mg i.v. followed by 8 mg/hr for 72 hrs for ASU with severe haemorrhage). With severe haemorrhage, fibrinolytic inhibitors (e.g. tranexamic acid 3-6 g i.v. daily) may also be of benefit. For lower gastrointestinal bleeding or if there is no obvious upper gastrointestinal lesion during endoscopy, then selective mesenteric angiography with embolisation of the bleeding point (if the bleeding is brisk, e.g. > 0.5-2.0 mL/min) or colonoscopy with electrocautery or adrenaline injection (for diverticular haemorrhage) may be considered as an alternative to surgery. CONCLUSIONS: Acute upper gastrointestinal bleeding is often managed by intravenous proton pump inhibitors and endoscopy with electrocautery or adrenaline injection when a bleeding at the base of an ulcer is found. For lower gastrointestinal haemorrhage, selective mesenteric angiography with embolisation of the bleeding point is an alternative to surgery in critically ill patients. Fibrinolytic inhibitors may have added benefit.
Journal Article↗
Acute gastrointestinal bleeding: Part II.
OBJECTIVE: To review the management of acute gastrointestinal bleeding in the critically ill patient in a two part presentation. DATA SOURCES: Articles and a review of studies reported from 1991 to 2001 and identified through a MEDLINE search of the English language literature on acute gastrointestinal bleeding. SUMMARY OF REVIEW: Oesophageal varices are a common source of upper gastrointestinal bleeding in patients who have portal hypertension. Management requires resuscitation and treatment of associated coagulation disturbances along with intravenous octreotide (50 microg followed by 50 microg/hr for 48 hr) before endoscopy is performed. Octreotide is more effective than vasopressin in controlling acute variceal suppressant and has fewer side effects compared with glypressin. To provide haemostasis, endoscopic variceal sclerosis has largely been replaced by variceal ligation using an overtube and small elastic 'o' rings to band the bleeding variceal channels. If bleeding continues then Balloon tamponade and intravenous fibrinolytic inhibitors (e.g. tranexamic acid 3-6 g i.v. daily) are used for 24 hr before endoscopy (with variceal ligation) is repeated. If the variceal bleeding is resistant to repeated banding, portal decompression using transjugular intrahepatic portosystemic shunt or surgical shunt should be considered. While beta adrenergic blockers (e.g. propranalol) are indicated to reduce the incidence of rebleeding, they are contraindicated in a patient with actively bleeding oesophageal varices. CONCLUSIONS: Acute oesophageal variceal bleeding can often be managed successfully using octreotide and variceal ligation. If bleeding continues then transjugular intrahepatic portosystemic shunt or surgical shunt should be considered.
Journal Article↗
E5 murine monoclonal antiendotoxin antibody in gram-negative sepsis: a randomized controlled trial. E5 Study Investigators.
CONTEXT: Knowledge and understanding of gram-negative sepsis have grown over the past 20 years, but the ability to treat severe sepsis successfully has not. OBJECTIVE: To assess the efficacy and safety of E5 in the treatment of patients with severe gram-negative sepsis. DESIGN: A multicenter, double-blind, randomized, placebo-controlled trial conducted at 136 US medical centers from April 1993 to April 1997, designed with 90% power to detect a 25% relative risk reduction, incorporating 2 planned interim analyses. SETTING: Intensive care units at university medical centers, Veterans Affairs medical centers, and community hospitals. PATIENTS: Adults aged 18 years or older, with signs and symptoms consistent with severe sepsis and documented or probable gram-negative infection. INTERVENTION: Patients were assigned to receive 2 doses of either E5, a murine monoclonal antibody directed against endotoxin (n = 550; 2 mg/kg per day by intravenous infusion 24 hours apart) or placebo (n = 552). MAIN OUTCOME MEASURES: The primary end point was mortality at day 14; secondary end points were mortality at day 28, adverse event rates, and 14-day and 28-day mortality in the subgroup without shock at presentation. RESULTS: The trial was stopped after the second interim analysis. A total of 1090 patients received study medication and 915 had gram-negative infection confirmed by culture. There were no statistically significant differences in mortality between the E5 and placebo groups at either day 14 (29.7% vs 31.1%; P = .67) or day 28 (38.5% vs 40.3%; P = .56). Patients presenting without shock had a slightly lower mortality when treated with E5 but the difference was not significant (28.9% vs 33.0% for the E5 and placebo groups, respectively, at day 28; P = .32). There was a similar profile of adverse event rates between E5 and placebo. CONCLUSIONS: Despite adequate sample size and high enrollment of patients with confirmed gram-negative sepsis, E5 did not improve short-term survival. Current study rationale and designs should be carefully reviewed before further large-scale studies of patients with sepsis are conducted.
Antibodies, Monoclonal↗
Successful separation of apoptosis and necrosis pathways in HaCaT keratinocyte cells induced by UVB irradiation.
UVB irradiation can induce apoptotic, necrotic, and differentiation pathways in normal human keratinocytes. The present study was undertaken to determine at what dose of UVB each of these pathways is induced and whether these pathways are distinct or overlapping. We have observed that UVB induces fragmentation of DNA in human HaCaT keratinocytes, in a bimodal manner. Low doses of UVB, 5-20 mJ/cm2, increase the levels of apoptosis as shown by increased levels of fragmented DNA, Fas, PARP, and FasL protein, and the number of apoptotic cells as assessed by FACS analysis. At higher doses of UVB (20 and 30 mJ/cm2) the number of apoptotic cells becomes reduced, as does the amount of Fas, PARP, and FasL protein. At these higher doses, cell viability is decreased as measured by DNA synthesis (BrdU labeling) neutral red uptake, which represents an increasing necrotic phenotype. Expression of markers of keratinocyte differentiation, involucrin, keratin K1, and keratin K10, are also observed to decrease with increasing UVB dose. These changes are accompanied by a further increase in DNA fragmentation. We conclude that low doses of UVB (5-20 mJ/cm2) induced an apoptotic pathway, whereas increasing doses (greater than 20 mJ/cm2) of UVB produce a direct necrotic effect and inhibit terminal differentiation.
Apoptosis↗