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PubMed1987

Pharmacokinetic studies on clavulanate potentiated ticarcillin in normal subjects and patients with renal insufficiency.

Pharmacokinetics of the novel combination of ticarcillin with the beta-lactamase inhibitor clavulanic acid (BRL 28500, Timentin, Betabactyl) was investigated in order to calculate the dose reduction factor (DRF) and elaborate dosage recommendations for patients with varying degrees of renal impairment. Serum and urine levels of ticarcillin and clavulanic acid have been determined following the i.v. application of 3.2 g and 5.2 g BRL 28500 consisting of 3.0 g and 5.0 g ticarcillin, respectively, and 0.2 g of clavulanic acid each. 10 healthy volunteers and 9 patients received the 5.2 g formulation, and 6 normal subjects and 9 patients the 3.2 g formulation. The pharmacokinetics of both components of BRL 28500 behave fairly similarly and provides the combination with a logic basis. The dose reduction factor, being 1 by definition in normal renal function, rises in final renal failure to 2-3 for clavulanic acid and to 4-5 for ticarcillin. A dosis reduction to 1/2-1/4 will roughly produce the same AUC in a patient with terminal renal insufficiency as the normal dosage in a healthy subject. The distribution volume of ticarcillin and clavulanic acid was found to be enlarged probably due to overhydration in this group of patients. The recovery of both BRL 28500 components decreased with impaired renal function. The recovery 6 h after administration of 0.2 g clavulanic acid in the 5.2 g (3.2 g) BRL 28500 formulation fell from 58 +/- 12% (52 +/- 6) in healthy subjects to 25 +/- 14% (25 +/- 13) in patients with renal insufficiency.(ABSTRACT TRUNCATED AT 250 WORDS)

Clavulanic Acids↗
PubMed2003

Pulmonary embolism in pregnant patients: a survey of practices and policies for CT pulmonary angiography.

OBJECTIVE: We surveyed the practices and policies of the radiology departments of the Society of Thoracic Radiology members regarding the use of CT pulmonary angiography in pregnant patients suspected of having pulmonary embolism. MATERIALS AND METHODS: Surveys were mailed electronically to the 403 members of the Society of Thoracic Radiology (403 addresses). Respondents were asked to send one response from each institution or department. Information gathered included use of CT angiography in relation to ventilation-perfusion imaging in pregnant patients, written policies, informed consent procedures, and modifications of standard protocols for dose reduction. RESULTS: Fifty-seven members responded; 43 (75%) reported that they perform CT angiography in pregnant patients suspected of having pulmonary embolism. Of the 43 respondents who perform CT angiography in pregnant patients, 23 (53%) generally perform CT angiography as the initial study rather than ventilation-perfusion scanning, 26 (60%) require informed consent from the patient, seven (16%) have a written policy concerning CT angiography in pregnant patients, and 17 (40%) modify standard imaging protocols for pregnant patients. The most common modification for dose reduction is decreasing the scanning area along the z-axis. CONCLUSION: Most respondents perform CT angiography in pregnant patients suspected of having pulmonary embolism, but their policies and practices vary considerably.

Angiography↗
PubMed1997

Preliminary results of a phase II study of paclitaxel and cisplatin in patients with non-small cell lung cancer.

Paclitaxel (Taxol; Bristol-Myers Squibb Company, Princeton, NJ) and cisplatin are cytotoxic drugs active against non-small cell lung cancer (NSCLC) that possess additive cytotoxicity in animal tumors. Paclitaxel and cisplatin are active in patients with advanced NSCLC when given on a 3-weekly schedule. In an attempt to increase activity, we designed a phase II study with a biweekly schedule. Paclitaxel 110 mg/m2 was given by 3-hour intravenous infusion, followed by cisplatin 60 mg/m2 via intravenous infusion. Treatment was scheduled every 2 weeks. Of the 42 patients treated, 19 were men and 23 were women, with a median age of 54 years (range, 31 to 69 years). Four patients had stage IIIA NSCLC, 18 stage IIIB, and 20 stage IV. Median World Health Organization performance status was 1 (range, 0 to 2), and adenocarcinoma was the most common histology (52%). A median of nine cycles was administered (range, one to 24 cycles), with more than 360 cycles administered. Rates of frequency of World Health Organization grade 3 or 4 toxicities were as follows: neutropenia, 20%; thrombocytopenia, 2%; nausea/vomiting, 7% (despite prophylactic treatment with 5-HT3 receptor antagonists plus prednisolone); neurotoxicity, 2%; and nephrotoxicity, 2%. There were three septicemic episodes, no bleeding episodes, and no toxic deaths. Dose reduction was performed in 15 patients (36%), due to nephrotoxicity in 14 cases. Treatment delay was necessary in 23 patients (55%), most often due to neutropenia (nine cases). Forty patients are currently evaluable for response, with two complete and 15 partial responses (overall response rate, 43%; 95% confidence limits, 27% to 59%). Median response duration was 31 weeks (range, 9 to 85 weeks). The biweekly schedule of paclitaxel plus cisplatin has noteworthy activity in patients with NSCLC. A relatively large fraction of patients required either dose reduction and/or treatment delay, but World Health Organization grade 3 or 4 toxicity was rare, apart from the neutropenia that caused only a few septicemic episodes.

Adult↗
PubMedDate not supplied

Efficacy of lidocaine or bupivacaine combined with ephedrine in rat sciatic nerve block.

BACKGROUND AND OBJECTIVES: The adrenergic drug ephedrine inhibits Na(+) current in cultured cells expressing Na(+) channels and provides dose-dependent reversible rat sciatic nerve blockade. The dosage required for peripheral nerve blockade in humans would cause unacceptable cardiovascular side effects. We therefore hypothesized that either lidocaine or bupivacaine would show synergy with ephedrine in a rat sciatic nerve block model, allowing a dose reduction and limiting side effects while improving efficacy. METHODS: Sciatic nerves of anesthetized rats were exposed by lateral incision of the thighs; 0.2 mL of different concentrations of the following drugs was injected sub-fascially: bupivacaine, lidocaine, and ephedrine alone and bupivacaine or lidocaine combined with ephedrine (n=8 per group). After animals recovered from anesthesia, a blinded investigator evaluated motor blockade (push against a balance) and sensory/nociceptive blockade (to pinch of the fifth toe) at predefined time intervals. RESULTS: Ephedrine combined with bupivacaine interacted additively for both motor and sensory blockade, and ephedrine combined with lidocaine interacted antagonistically (sub-additive) for sensory blockade and additively for motor blockade. CONCLUSIONS: A combination of ephedrine with either lidocaine or bupivacaine is unlikely to allow a significant dose reduction because of a lack of synergy. Furthermore, the cardiovascular side effects will limit the maximal tolerable dosage of ephedrine.

Adrenergic Agents↗
PubMed2006

Recurrent gastrointestinal stromal tumor (GIST) of the stomach associated with a novel c-kit mutation after imatinib treatment.

A 57-year-old man with gastrointestinal stromal tumor (GIST) of the stomach with peritoneal dissemination underwent gastrectomy. After surgery, he was treated with 400 mg/day of imatinib, without recurrence, for 26 months. At 26 months, the imatinib dose was reduced because of nausea, and 4 months after the dose reduction, recurrence of GIST was detected, for which surgical resection was performed again. The first surgical specimen had a mutation of exon 11 in the c-kit receptor gene. Intriguingly, the second surgical specimen had a novel mutation of exon 17, in addition to the above-mentioned mutation, in the c-kit receptor gene. Based on the result of molecular analysis, the novel mutation of exon 17, induced by longterm chemotherapy, was judged to have been responsible for the recurrence, which perhaps was triggered by the dose reduction of imatinib.

Antineoplastic Agents↗
PubMedDate not supplied

[Reducing radiation dosage to 20-30 Gy in combined chemo-/radiotherapy of Hodgkin's disease in childhood. A report of the cooperative DAL-HD-87 therapy study].

UNLABELLED: The main objective of the multicenter study DAL-HD-87 was to evaluate for the involved-field irradiation a dose reduction by 5 Gy compared with the precursor studies HD-82 and HD-85. Moreover, the decisional strategy for selective laparotomy developed on the basis of retrospective analyses in study HD-82 was to be tested in a prospective design. Chemotherapy in group 1 (stages I, IIA) consisted in 2 OPA cycles (vincristine, prednisone, adriamycin). Group 2 (stages IIEA, IIB, IIIA) received 2 x OPA + 2 x COP(P), and group 3 (stages IIEB, IIIB, IV) 2 x OPPA (with procarbacine) + 4 x COP(P). For the subsequent radiotherapy, doses of 30, 25, and 20 Gy respectively were applied in the 3 groups. Fields with incomplete lymphoma regression were to receive an additional boost of 5-10 Gy. -Exploratory laparotomy was considered indicated in the event of abnormal findings in abdominal CT/ultrasonography and/or enlargement of lymph nodes at the pulmonary hilus. RESULTS: From Dec. 1986 to Sept. 1990, 204 pts from 51 centres were enrolled in the study. 196 were evaluable. 109 pts (55.6%) were laparotomized, 58 (29.6%) splenectomized. The accuracy for the prediction of an abdominal involvement was 72.3% in case of abnormal findings in abdominal CT/ultrasound but only 36.4% in case of enlarged lymph nodes at the pulmonary hilus without abdominal abnormalities. 91.2% of the removed spleens were proven involved. -2 out of 196 pts suffered progression under treatment, and 22 relapsed (as of 1 Jan, 1994). 6 pts died, 4 of whom succumbed to Hodgkin's disease, and 2 to intercurrent infections. 2 pts in first remission developed a secondary malignancy, namely 1 malignant histiocytoma in radiation field and 1 ANLL. Another patient developed a thyroid carcinoma following salvage therapy for a relapse. The probabilities of event-free survival (EFS) and survival after 7 years are for the total group: 85% and 97%, in group 1: 84% and 99%, in group 2: 82% and 93%, and group 3: 89% and 95%. Comparison with the precursor studies HD-82 and HD-85 reveals that the dose reduction in radiotherapy has not affected the results. Differences in EFS are exclusively correlated with changes in chemotherapy.

Adolescent↗
PubMed2005

Gemcitabine in the treatment of relapsed and refractory Hodgkin's disease.

BACKGROUND: Patients with refractory Hodgkin's disease or relapsing after high-dose therapy and autografting have a poor prognosis. Here, we present our experiences with gemcitabine in this setting. PATIENTS AND METHODS: We treated 14 patients with relapsed or refractory Hodgkin's disease with gemcitabine. The treatment was given on a compassionate use basis, off-label and not according to a study protocol. Patients were 17-46 years of age. 1 patient had stage IA disease, 2 patients had stage IIIB disease and 11 patients had stage IVB disease. 9 patients had received radiotherapy. 8 patients had been autografted and 1 patient auto- and allografted. Gemcitabine was administered at a starting dose of 1 g/m(2) on days 1 and 8 every 3 weeks in combination with steroids. RESULTS: The median follow-up period was 10 months. Hematological toxicity grade 3-4 occurred in 12 patients leading to dose reductions. 1 patient died of neutropenic sepsis. No other non-hematological toxicities were observed. The response rate was 64% with 6 patients achieving complete remission (CR) and 3 patients partial remission (PR). The median time to treatment failure was 9 months, and survival was 11 months. Responses were seen in previously transplanted patients and in patients refractory to previous treatment. The so far longest responder has been in CR for over 68 months. CONCLUSION: Gemcitabine is an effective treatment for Hodgkin's disease. Heavily pretreated patients often require dose reductions.

Adolescent↗
PubMed2004

Treating hepatitis C: the state of the art.

Treatment of chronic hepatitis C has improved significantly, but more effective and well-tolerated therapies are needed. While new therapies are being developed, it is important to optimize the use of currently available treatments. Current treatment regimens are associated with substantial side effects, especially hematologic and neuropsychiatric side effects, that can lead to nonadherence, dose reduction, and treatment discontinuation. Because treatment adherence is critical to achieving a sustained virologic response, especially in patients who have genotype 1, early recognition and appropriate management of these side effects should lead to improved patient outcomes. Pending the availability of new therapies, further progress can be made mainly by maximizing benefits for individuals infected with HCV through appropriate selection of patients for antiviral treatment and increasing treatment adherence through better patient and caregiver education, closer patient follow-up, and more aggressive management of the side effects that lead to dose reduction or discontinuation. Further clinical and research efforts are needed to expand treatment to subgroups of patients previously considered ineligible because of comorbidities such as psychiatric and substance-use disorders. Optimum management of patients with hepatitis C will involve a larger cooperative team effort that includes physician specialists from various disciplines, including mental health care providers and physician extenders. Continued efforts are needed to develop novel therapies and treatment approaches to benefit patients who do not respond to current therapies, to increase our understanding of the natural history and pathology of HCV infection, and to promote public education to better identify infected individuals and improve hepatitis C prevention.

Antiviral Agents↗
PubMed1989

A randomized, controlled dose response study of intravenous sodium diethyldithiocarbamate in patients with advanced human immunodeficiency virus infection.

Sodium diethyldithiocarbamate (Imuthiol, DTC) has previously been observed to promote T-cell maturation in animal models and to reduce lymphadenopathy and improve survival in a murine AIDS model. In addition, several clinical studies have suggested that one dosage regimen may be active in patients with HIV infection. We conducted a randomized, controlled dose response study of intravenous DTC in patients with the acquired immunodeficiency syndrome (AIDS) and AIDS-related complex (ARC). Drug associated toxicities included gastrointestinal upset, burning at the infusion site, metallic taste, sneezing, confusional states, hyperactivity, delusional thinking, and myoclonus. Toxicity was ameliorated by dose reduction. The maximally tolerated dose varied for individual patients from 200 mg/m2 weekly to 800 mg/m2 twice weekly. No myelosuppression was observed. In patients with greater than 200 CD4+ cells/uL, a statistically significant reduction of lymphadenopathy occurred; whereas no beneficial effects were observed in patients with less than 200 CD4+ cells/uL. Improvement in symptom score and stabilization of CD4+ count also occurred in the treated group, although these trends did not reach statistical significance. Further controlled clinical trials of DTC in earlier HIV infection are warranted.

AIDS-Related Complex↗
PubMed1996

[Combination therapy of circumscribed choroid hemangioma in contralateral Sturge-Weber syndrome with acetazolamide and laser coagulation].

BACKGROUND: In Sturge-Weber syndrome choroidal hemangiomas occur in up to 55%. With a few exceptions it is a diffuse hemangioma and it always affects the eye ipsilateral to the naevus flammeus. To the best of our knowledge, a contralateral circumscribed choroidal hemangioma has not yet been described. HISTORY AND CLINICAL FINDINGS: We present a 34-year-old male caucasian with a left-sided naevus flammeus and a right-sided circumscribed choroidal hemangioma. Ipsilateral to the naevus, the left eye showed typical vascular anomalies of the conjunctiva and episclera as well as in the anterior chamber angle with anterior synechia formation and circumscribed iris atrophy without secondary glaucoma. Retinal and choroidal vasculature was normal. In the contralateral eye the anterior segment was normal, but there was a juxtafoveolar circumscribed choroidal hemangioma of about 7.5 x 4.5 mm along the superior temporal vascular arcade. The tumor was detected when vision dropped to 0.4 due to an exsudative retinal detachment over the tumor involving the fovea. THERAPY AND CLINICAL COURSE: Complete regression of the exsudative detachment occurred under oral Acetazolamide (1000 mg/d), but after dose reduction to 500 mg/d the exsudation recurred. Thereafter, the surface of the tumor was treated with argongreen grid lasercoagulation in 3 sessions under Acetazolamide cover. Following scar formation the retina has stayed completely attached even after discontinuation of oral Acetazolamide therapy with a follow-up of now 7 months. CONCLUSIONS: Visual prognosis after exsudative macula detachment is depended on rapid retinal reattachment. Therefore, early and effective treatment is mandatory. Systemic application of Acetazolamid (1000 mg/d orally) led to a rapid reattachment of the retina with an excellent visual result. However, dose-reduction was followed by an immediate recurrency. We therefore suggest to perform an Argongreen grid lasercoagulation of the tumor surface while the patient is still under systemic Aceazolamid. This strategy has proven successful in this case.

Acetazolamide↗
PubMed2004

Impact of late conversion from C0 to C2 monitoring of microemulsified cyclosporine in pediatric living donor liver transplant recipients.

The efficacy and feasibility of 2-h post-dose level (C2) monitoring of cyclosporine in long-term living donor liver transplantation (LDLT) is not clear. The aim of this study was to investigate the impact of late conversion from conventional trough-level (C0) monitoring to C2 monitoring of a microemulsion form of cyclosporine (Neoral) in pediatric LDLT recipients. From June 1994 to August 2002, we performed 116 LDLTs in 115 patients. Initially, we adapted conventional C0 monitoring of Neoral, which was converted to C2 monitoring starting in January 2002. The 60 patients who were enrolled in the study had the following characteristics: they were younger than or equal to 15 yr at transplantation, and they had survived LDLT, and they had received a Neoral-based immunosuppression regimen, and they underwent conversion to C2 more than 1 month after transplantation. We evaluated the impact of conversion on doses, blood levels, rejection, adverse effects, and patient/graft outcome. In the long-term patients, the mean C2 levels immediately after conversion were higher than the target levels at any time point selected after transplantation; thus, 34 patients (57%) finally required a dose reduction of Neoral. The current mean C2 level was significantly lower than that observed immediately after conversion (584.6 +/- 262.8 ng/ml vs. 893.1 +/- 260.2 ng/ml, mean +/- SD, p < 0.0001) with a mean follow-up period of 7.4 +/- 0.6 months (range: 5-8 months) after conversion. Only one patient encountered rejection after conversion (1.7%), and no de novo infection or adverse effects were observed. Traditional C0 monitoring of Neoral was safely replaced by C2 monitoring without an increase in the rejection rate or any adverse effects in pediatric LDLT patients. C2 monitoring contributed to the dose reduction of Neoral, which may lead to the avoidance of long-term complications due to immunosuppression.

Adolescent↗
PubMed2006

Low-level laser therapy induces dose-dependent reduction of TNFalpha levels in acute inflammation.

OBJECTIVE: The aim of this study was to investigate if low-level laser therapy (LLLT) can modulate acute inflammation and tumor necrosis factor (TNFalpha) levels. BACKGROUND DATA: Drug therapy with TNFalpha-inhibitors has become standard treatment for rheumatoid arthritis, but it is unknown if LLLT can reduce or modulate TNFalpha levels in inflammatory disorders. METHODS: Two controlled animal studies were undertaken, with 35 male Wistar rats randomly divided into five groups each. Rabbit antiserum to ovalbumin was instilled intrabronchially in one of the lobes, followed by the intravenous injection of 10 mg of ovalbumin in 0.5 mL to induce acute lung injury. The first study served to define the time profile of TNFalpha activity for the first 4 h, while the second study compared three different LLLT doses to a control group and a chlorpromazine group at a timepoint where TNFalpha activity was increased. The rats in LLLT groups were irradiated within 5 min at the site of injury by a 650-nm Ga-Al-As laser. RESULTS: There was a time-lag before TNFalpha activity increased after BSA injection. TNFalpha levels increased from < or =6.9 (95% confidence interval [CI], 5.6-8.2) units/mL in the first 3 h to 62.1 (95% CI, 60.8-63.4) units/mL (p < 0.001) at 4 h. An LLLT dose of 0.11 Joules administered with a power density of 31.3 mW/cm(2) in 42 sec significantly reduced TNFalpha level to 50.2 (95% CI, 49.4-51.0), p < 0.01 units/mL versus control. Chlorpromazine reduced TNFalpha level to 45.3 (95% CI, 44.0-46.6) units/mL, p < 0.001 versus control. CONCLUSION: LLLT can reduce TNFalpha expression after acute immunocomplex lung injury in rats, but LLLT dose appears to be critical for reducing TNFalpha release.

Animals↗
PubMed1999

Interferon treatment of chronic active hepatitis C during therapy of acute lymphoblastic leukemia.

Due to concerns that antineoplastic therapy produces prolonged decrease in immune function, interferon treatment of chronic active hepatitis C (CAHC) has been used only at one year or longer after the end of cancer therapy. We report the experience of an 11-year-old who developed symptomatic CAHC at the start of maintenance therapy for testicular relapse of acute lymphoblastic leukemia (ALL). Significant dose reduction of maintenance therapy did not improve the tolerance of antileukemic treatment. In an effort to improve his liver disease and to deliver effective antileukemic therapy, interferon alpha and an alternative maintenance therapy regimen for ALL were initiated. The patient tolerated the combined therapy well. Interferon therapy was continued for 27 months, which was three months from the end of antineoplastic therapy. At that time serum transaminase values were normal, and no HCV viral genome was detectable. Viral genome was detected 10 months later. The combined effects of interferon and antineoplastic therapy resulted in myelosuppression requiring dose reduction of both treatments. The patient remains asymptomatic and with no evidence of recurrent leukemia more than six years from diagnosis of relapse. The effect on the status of this patient's CAHC was similar to that reported among leukemic patients who underwent an interferon course more than one year from the end of antineoplastic therapy. Interferon treatment of CAHC can be given concomitantly with antineoplastic therapy.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed2004

Nitric oxide donor induces temporal and dose-dependent reduction of gene expression in human endothelial cells.

The present study tested the hypothesis that acute increases in nitric oxide (NO) exert substantial influences on gene transcription in endothelial cells (ECs) via guanylyl cyclase (GC). Human umbilical veins ECs (HUVECs) were exposed to 0.1, 1, and 10 mM of sodium nitroprusside (SNP) for 4 h and to 1 mM SNP or 250 microM of (Z)-1[N-(2-aminoethyl)-N-(2-ammonioethyl)amino]diazen-1-ium-1,2-diolate (DETA-NONOate) for 2, 4, 8, and 24 h. Also, cells were exposed to DETA-NONOate in the presence and absence of the GC inhibitor 1H-[1,2,4]oxadiazolo-[4,3-a]quinoxalin-1-one (ODQ; 10 microM) for 4 h. RNA was isolated, reverse transcribed, Cy3 and Cy5 labeled, and analyzed using cDNA microarrays. Increasing doses of SNP predominantly depressed gene expression in HUVECs. Gene function was related to growth, adhesion, and cell structure. DETA-NONOate evoked a wave of expression changes (maximum at 4 h), with a remarkable downregulation of the transcription factors MSX1, RELB, and Egr-1. Both SNP- and DETA-NONOate-induced gene expression had faded after 24 h, despite continued elevation of cGMP in the medium. Coadministration of ODQ decreased many, but not all, of the transcriptional responses to DETA-NONOate. NO pronouncedly depressed EC gene expression, in particular of transcription factors. The observation that many, but not all, transcriptional changes induced by NO could be inhibited by inhibition of GC indicates the presence of GC-independent NO actions on gene expression. Thus EC gene expression responds to NO; however, the transcriptional response fades during prolonged exposure. This could allow the EC to respond to increased shear, without vigorous changes in gene expression.

Cell Survival↗
PubMed2004

A prospective, randomized study of coadministration of ketoconazole and cyclosporine a in kidney transplant recipients: ten-year follow-up.

BACKGROUND: In a prospective, randomized study, we previously proved the safety and financial benefits of the coadministration of ketoconazole (keto) and cyclosporine A (CsA) in patients. We report the 10-year follow-up of these patients and the controls. PATIENTS AND METHODS: In January 1992, 100 living-related kidney transplant recipients were randomized into two groups: Group 1 (51 patients) received 100 mg/day keto, and group 2 (49 patients) did not receive keto (control). Both groups were evaluated regarding graft function, CsA dose and levels, liver function tests, serum calcium and phosphorus, bone mineral density, and histopathologic assessment. RESULTS: Follow-up for 10 years showed that CsA dose reduction was maximum after 1 month (76.5%) and decreased gradually after 10 years (64.6%). Acute rejection was diagnosed in 22% and 27% in the keto and control groups, respectively (P =0.27). In the control group, the acute rejection episodes were more frequent with poorer response to treatment. Chronic allograft nephropathy was statistically significantly less in the keto group. Hepatotoxicity and metabolic complications were similar in both groups. The annual cost saving of CsA was 60% after 1 year and 50% at the end of the study. CONCLUSIONS: We conclude that the long-term use of keto for CsA dose reduction in kidney transplant recipients is safe, tolerable, and cost-sparing and is associated with stable graft function.

Adult↗
PubMed1997

Application of a gamma extremity monitoring system in a radiopharmaceutical dispensary.

A new gamma extremity monitoring system (GEMS) was used to assess finger doses of staff working in a hospital radionuclide dispensary. The system is designed to give a continuous readout of dose rate from a small probe which may be attached to a finger. It allows the contributions to radiation dose to the fingers from different parts of a procedure to be measured for the first time and the detailed pattern of radiation exposure to be determined. The dose reduction benefits of small changes in procedure and the use of syringe shields were easily demonstrated after monitoring staff for a few sessions using GEMS, which would not have been possible using thermoluminescent or other integrating dosemeters. GEMS was calibrated against 99Tc(m), 241Am, 137Cs and 131I. The main disadvantage of the system is that the response of the detector increases significantly at lower radiation energies, with that at 60 keV being approximately 70 times the response at 662 keV. In addition, the response of the current detector is nonlinear and saturates around 7000 counts s(-1), which corresponds to a dose rate of 2200 microGy h(-1) for 99Tc(m). Despite these drawbacks, GEMS can play a significant part in the analysis of finger dose patterns and assist in dose reduction.

Americium↗
PubMed2005

[Dose optimization for multislice computed tomography protocols of the midface].

PURPOSE: To optimize multislice computed tomography (MSCT) protocols of the midface for dose reduction and adequate image quality. MATERIALS AND METHODS: MSCT (Somatom Volume Zoom, Siemens) of the midface was performed on 3 cadavers within 24 hours of death with successive reduction of the tube current, applying 150, 100, 70 and 30 mAs at 120 kV as well as 40 and 21 mAs at 80 kV. At 120 kV, a pitch of 0.875 and collimation of 4x1 mm were used, and at 80 kV, a pitch of 0.7 and collimation of 2x0.5 mm. Images were reconstructed in transverse and coronal orientation. Qualitative image analysis was separately performed by two radiologists using a five-point scale (1 = excellent; 5 = poor) applying the following parameters: image quality, demarcation and sharpness of lamellar bone, overall image quality, and image noise (1 = minor; 5 = strong). The effective body dose [mSv] and organ dose [mSv] of the ocular lens (using the dosimetry system "WINdose") were calculated, and the interobserver agreement (kappa coefficient) was determined. RESULTS: For the evaluation of the lamellar bone, adequate sharpness, demarcation and image quality was demonstrated at 120 kV/30 mAs, and for the overall image quality and noise, 120 kV/40 mAs was acceptable. With regard to image quality, the effective body dose could be reduced from 1.89 mSv to 0.34 mSv and the organ dose of the ocular lens from 27.2 mSv to 4.8 mSv. Interobserver agreement was moderate (kappa = 0.39). CONCLUSION: Adequate image quality was achieved for MSCT protocols of the midface with 30 mAs at 120 kV, resulting in a dose reduction of 70 % in comparison to standard protocols.

Face↗
PubMed1992

FK506-induced impairment of glucose metabolism in the primate--studies in pancreatic transplant recipients and in nontransplanted animals.

The effect of FK506 on glucose metabolism was studied in five cynomolgus monkeys after pancreatic transplantation and in 10 nontransplanted cynomolgus monkeys. We have clearly demonstrated that FK506 can induce hyperglycemia in these animals. In the orally treated nontransplanted animals the hyperglycemia was usually very mild (4.5-6.0 mmol/L). In one of the five transplanted animals, hyperglycemia was induced by the FK506 treatment, since histological signs of rejection were absent and since plasma glucose levels normalized on dose reduction. The glucose disappearance rates, as indicated by the K-values, decreased from a mean of 3.0 +/- 0.5%/min before FK506 treatment to 2.4 +/- 0.6%/min at one month and 1.5 +/- 0.4%/min at three months in the nontransplanted animals. In the transplant group, the K values decreased significantly from 4.2 +/- 0.6%/min in the donor animals to 1.4 +/- 0.4%/min at day 10 posttransplantation (P < 0.02). At one and three months postoperatively, the mean K-values were 1.4 +/- 0.2%/min and 1.2 +/- 0.6%/min, respectively. We conclude that FK506 is diabetogenic in the cynomolgus monkey. This side effect, however, was found to be reversible on dose reduction.

Animals↗