Effect of aspirin in vascular surgery in patients from a randomized clinical trial (POISE-2).

BACKGROUND: In the POISE-2 (PeriOperative ISchemic Evaluation 2) trial, perioperative aspirin did not reduce cardiovascular events, but increased major bleeding. There remains uncertainty regarding the effect of perioperative aspirin in patients undergoing vascular surgery. The aim of this substudy was to determine whether there is a subgroup effect of initiating or continuing aspirin in patients undergoing vascular surgery. METHODS: POISE-2 was a blinded, randomized trial of patients having non-cardiac surgery. Patients were assigned to perioperative aspirin or placebo. The primary outcome was a composite of death or myocardial infarction at 30 days. Secondary outcomes included: vascular occlusive complications (a composite of amputation and peripheral arterial thrombosis) and major or life-threatening bleeding. RESULTS: Of 10 010 patients in POISE-2, 603 underwent vascular surgery, 319 in the continuation and 284 in the initiation stratum. Some 272 patients had vascular surgery for occlusive disease and 265 had aneurysm surgery. The primary outcome occurred in 13·7 per cent of patients having aneurysm repair allocated to aspirin and 9·0 per cent who had placebo (hazard ratio (HR) 1·48, 95 per cent c.i. 0·71 to 3·09). Among patients who had surgery for occlusive vascular disease, 15·8 per cent allocated to aspirin and 13·6 per cent on placebo had the primary outcome (HR 1·16, 0·62 to 2·17). There was no interaction with the primary outcome for type of surgery (P = 0·294) or aspirin stratum (P = 0·623). There was no interaction for vascular occlusive complications (P = 0·413) or bleeding (P = 0·900) for vascular compared with non-vascular surgery. CONCLUSION: This study suggests that the overall POISE-2 results apply to vascular surgery. Perioperative withdrawal of chronic aspirin therapy did not increase cardiovascular or vascular occlusive complications. Registration number: NCT01082874 ( http://www.clinicaltrials.gov).

Impact of anti-tobacco warning labels on behaviour of tobacco users in one of the cities of Gujarat, India.

BACKGROUND: Tobacco use continues to be the leading global cause of preventable deaths, killing nearly 6 million people worldwide each year. Tobacco control must be given the high priority by scaling up tobacco control measures. In India under Control of Tobacco Product Act, it is mandatory to keep the warning labels over all kind of tobacco products in order to minimise the use of tobacco. OBJECTIVES: Review of the knowledge regarding warning labels printed on tobacco products among its users and to evaluate the impact of them on addicting behaviour. METHODOLOGY: A Cross Sectional study was carried out among the group of people using tobacco in any form. Total 776 tobacco users were enrolled in the study. RESULTS: Mean age of tobacco user was 41.4 years. Out of total 776 tobacco users, 561 (72.3%) had ever noticed warning signals over the tobacco products. Among those who have noticed warning labels, 64.4 % became aware about health effects and 66% have thought to quit tobacco. Tobacco users of young age group (15-45) were more aware regarding warning labels. Females were less aware. As level of education increases number of tobacco users who tried to quit or reduced the daily quantity of tobacco intake were also increases. CONCLUSIONS: Positive impact of warning labels has been seen among the tobacco users who have noticed them. Not all the tobacco users were aware regarding the presence of warning labels as per the findings of present study.

LTSI Consensus Guidelines: Preoperative Pulmonary Evaluation in Adult Liver Transplant Recipients.

The relationship between chronic liver disease and respiratory symptoms and hypoxia is well recognized. Over the last century, three pulmonary complications specific to chronic liver disease (CLD) have been characterized: hepatopulmonary syndrome, portopulmonary hypertension, and hepatic hydrothorax. Apart from that coexisting pulmonary disease like chronic obstructive lung disease and interstitial lung disease also complicate the outcomes after liver transplantation (LT). Assessment for evaluation of underlying pulmonary disorders is essential to improve outcomes in patients with CLD, posted for LT. This consensus guideline of the Liver Transplant Society of India (LTSI) provides a comprehensive review of pulmonary issues in CLD, related and unrelated to underlying liver disease and gives recommendations for pulmonary screening in specific clinical scenarios in adults with chronic liver disease planned for LT. This document also aims to standardize the strategies for preoperative evaluation of these pulmonary issues in this subset of patients. Proposed recommendations were based on selected single case reports, small series, registries, databases, and expert opinion. The paucity of randomized, controlled trials in either of these disorders was noted. Additionally, this review will highlight the lacunae in our current evaluation strategy, challenges faced, and will provide direction to potentially useful futuristic preoperative evaluation strategies.

Synthesis of C3-symmetric and C4-symmetric amino acid derivatives via Suzuki-Miyaura cross-coupling reaction.

Various non-natural C(3)- and C(4)-symmetric alpha-amino acid derivatives have been synthesized via Suzuki-Miyaura cross-coupling reaction between aromatic iodides or bromide and a suitably protected DL-4-boronophenylalanine derivative.

Design and synthesis of a novel anthracene-based fluorescent probe through the application of the Suzuki-Miyaura cross-coupling reaction.

We report on a simple synthetic route to a novel anthracene-based bis-armed amino acid derivative as a useful fluorescent probe. Various photophysical studies of this amino acid derivative are also described. Here, Suzuki-Miyaura cross-coupling reaction has been used as a key step for carbon-carbon bond formation.

Aggressive management of multiorgan donor.

Transplantation of vital human organs is a lifesaving therapy for patients with end-stage organ failure who are medically fit to undergo the surgical procedure. However, deceased donor management remains one of the most neglected areas in transplantation medicine. Brainstem death leads to hemodynamic, metabolic, and immune consequences. Failure to recognize them and provide adequate physiological support accounts for loss of the scarce source of valuable donor organs. Donor optimization leads to increased organ procurement and contributes to improved organ function in the recipient. This article reviews the management advances and controversies of the brainstem-dead donor in an intensive care unit.

Carbon dioxide absorption during laparoscopic donor nephrectomy: a comparison between retroperitoneal and transperitoneal approaches.

AIM: Previous studies have suggested that retroperitoneal and transperitoneal approaches for laparoscopic donor nephrectomy are associated with variable carbon dioxide (CO(2)) absorption, which can cause significant morbidity. The approach that results in greater CO(2) absorption is a matter of debate. We studied patients undergoing transperitoneal/retroperitoneal donor nephrectomy to determine relative CO(2) absorption, incidence of subcutaneous emphysema, pneumothorax, and pneumomediastinum, seeking to establish a correlation between the incidence of subcutaneous emphysema and CO(2) elimination. MATERIALS AND METHODS: This was a prospective nonrandomized, single-center, two-arm clinical study of 60 kidney donors undergoing laparoscopic nephrectomy by transperitoneal (n = 30) or retroperitoneal (n = 30) approach. CO(2) elimination was calculated using end tidal CO(2), tidal volume, respiratory rate, and weight of the donor. We studied intraoperative CO(2) elimination and CO(2) retention-related morbidities. RESULTS: There was a significant increase in CO(2) elimination in the first 30 minutes of insufflation followed by a plateau for the remainder of procedure. There was no difference in CO(2) elimination in either procedure at any time interval. Patients with subcutaneous emphysema showed significantly greater CO(2) elimination, which decreased with desufflation. CONCLUSION: CO(2) absorption during laparoscopy did not depend on the route of surgery. Subcutaneous emphysema was strongly and independently associated with a greater degree of CO(2) absorption during laparoscopic surgery.

Combined epidural and general anesthesia for paediatric renal transplantation-a single center experience.

BACKGROUND: Appropriate anesthesia for pediatric renal transplantation requires stable intraoperative hemodynamics, optimal perfusion of the newly transplanted kidney and good analgesia during recovery. The aim of this study was to assess the preliminary application, success and safety of combined epidural and general anesthesia in pediatric renal transplantation in a small cohort. METHODS: We retrospectively reviewed the anesthesia records of 46 consecutive pediatric patients who received renal transplantation under combined epidural and general anesthesia from January 2003-2007. RESULTS: The mean patient age and weight were 13.2 +/- 2.4 years and 25.7 +/- 5.46 kg, respectively. The infused crystalloids, 20% albumin and red blood cell concentrates were 120 +/- 2 mL/kg to achieve a CVP of 13 to 15 mm Hg. Brisk diuresis was observed in all patients. Epidural tramadol (2 mg/kg) provided good postoperative analgesia in 89% patients. 15% patients developed radiological evidence of pulmonary edema, only one required mechanical ventilation for hypoxemia. Minor adverse effects were nausea and vomiting (17.5%) and convulsions (8.5%). No perioperative mortality or major morbidity was recorded. CONCLUSION: Epidural anesthesia is a useful adjunct to general anesthesia due to stable intraoperative haemodynamics and good postoperative analgesia.

The use of symmetry to correct Larmor phase aberrations in spin echo scattering angle measurement.

Spin echo scattering angle measurement (SESAME) is a sensitive interference technique for measuring neutron diffraction. The method uses waveplates or birefringent prisms to produce a phase separation (the Larmor phase) between the "up" and "down" spin components of a neutron wavefunction that is initially prepared in a state that is a linear combination of in-phase up and down components. For neutrons, uniformly birefringent optical elements can be constructed from closed solenoids with appropriately shaped cross sections. Such elements are inconvenient in practice, however, both because of the precision they demand in the control of magnetic fields outside the elements and because of the amount of material required in the neutron beam. In this paper, we explore a different option in which triangular-cross-section solenoids used to create magnetic fields for SESAME have gaps in one face, allowing the lines of magnetic flux to "leak out" of the solenoid. Although the resulting field inhomogeneity produces aberrations in the Larmor phase, the symmetry of the solenoid gaps causes the aberrations produced by neighboring pairs of triangular solenoids to cancel to a significant extent. The overall symmetry of the SESAME apparatus leads to further cancellations of aberrations, providing an architecture that is easy to construct and robust in performance.

Prevalence and Predictors of Abuse in Elderly Patients with Depression at a Tertiary Care Centre in Saurashtra, India.

CONTEXT: Elder abuse has devastating consequences such as poor quality of life, psychological distress and loss of property and security. Abuse of elderly patients with depression has not been adequately researched in India. AIMS: To explore the prevalence and predictors of abuse and its relation to various sociodemographic variables in elderly patients with depression. SETTINGS AND DESIGN: A cross-sectional, observational study carried out at a tertiary care centre in Jamnagar. METHODS AND MATERIALS: In all, 100 elderly patients with depression, attending Out Patient Department of Psychiatry at Shree M. P. Shah Government Medical College and Guru Gobind Singh Hospital, Jamnagar, were selected using simple random sampling by lottery method. Actual Abuse Tool and Elder Abuse Suspicion Index were used to detect abuse. Geriatric Depression Scale was used to assess depression, and Mini Mental State Examination was used to rule out dementia. STATISTICAL ANALYSIS: Descriptive statistics, Chi-square test, and binary logistic regression were used. RESULTS: The prevalence of abuse was 24%. Among those who had experienced abuse, 50% had experienced psychological abuse, 17% had experienced neglect, 8% had experienced exploitation and 4% had experienced physical abuse. About 54% of patients with severe depression had experienced abuse. Daughters-in-law (54%) and sons (42%) were the most common perpetrators. Illiteracy and severe depression were found to be the predictors of abuse.

Impact of retroperitoneoscopic donor nephrectomy on renal allograft in Indian and African recipients.

AIM: To evaluate the impact of laparoscopic donor nephrectomy on renal allografts in Indian and African recipients. MATERIAL AND METHODS: Between September 2004 and August 2006, 125 retroperitoneoscopic donor nephrectomies were performed. Ninety-four donors were Indian (group A) and 32, African (group B). Three ports were used for left-sided and four for right-sided surgery, respectively. Hem-o-lok clips were used to control arteries and veins on left side and arteries on right side while an Endo-TA stapler was used on the right side to obtain an inferior vena caval cuff. RESULTS: The mean operative times in groups A and B were 130 and 134 minutes; mean blood loss, 100.4 mL and 85.3 mL; and mean warm ischemia time, 242.1 seconds and 234.5 seconds, respectively. Recipient mean serum creatinine value on day 7 was 1.9 and 1.6 mg%, and on day 28, 1.44 mg% and 1.4 mg%, respectively. CONCLUSION: Early adequate allograft function following retroperitoneoscopic donor nephrectomy was comparable in African and Indian patients, suggesting that no racial advantage was observed in this procedure.

In pursuit of the ultimate: the initial Ahmedabad journey toward transplantation tolerance.

We designed a prospective clinical trial of 357 patients divided in two groups--treated (n = 201) and controls (n = 156)--to evaluate effects of donor hematopoietic stem cell transplantation (HSCT) with minimal nonmyeloablative conditioning for tolerance induction in living related donor renal allograft recipients. Conditioning included donor leukocyte infusions, target-specific irradiation, anti-T-cell antibody, cyclophosphamide, cyclosporine (CsA), followed by bone marrow (BM)-derived and peripheral blood stem cell (PBSC) infusion into thymus, liver, BM, and periphery, with mean total dose of 20 x 10(8) nucleated cells/kg body weight (BW) (mean CD34(+) count: 0.9%) pretransplantation. CsA (3 mg/kg BW/d) and prednisolone (10 mg/d) were used for immunosuppression. Azathioprine/mycophenolate mofetil were added in the event of an acute rejection episode. The controls underwent transplantation with three drug immunosuppression. With a mean follow-up of 21.5 months, the treated cohort showed better allograft function with mean serum creatinine (SCr), 1.42 +/- 0.31 mg% in contrast with the controls mean SCr, 1.61 +/- 0.52 mg% (P < .0001) at 23.9 months follow-up. One-year allograft/patient survival was 95%/96.7% versus 89%/93.4%, respectively. Peripheral blood chimerism by fluorescent in situ hybridization was 0.8% +/- 0.2% in the subset of treated patients with gender-mismatched donors. No graft-versus-host disease was noted. Nine patients with donor-specific cytotoxic alloantibodies pretransplantation showed a decrease in positivity to <15% post-HSCT and were transplanted safely. A transient rise in donor-specific cytotoxic alloantibodies was noted in 19 treated patients post-HSCT, 14 of whom returned to the transplantable range within 2 weeks and five required a desensitization protocol. "Prope" tolerance may be induced in living related donor renal transplantation across major histocompatability complex barriers using HSCT with minimal nonmyeloablative conditioning.

Successful generation of donor specific hematopoietic stem cell lines from co-cultured bone marrow with human embryonic stem cell line: a new methodology.

We report the generation of 30 healthy human embryonic stem cell (h-ESC) lines from 33 voluntary oocyte donors using a donor somatic cell nuclear transfer (SCNT) technique on 190 oocytes. Our aim was to coculture them with their own bone marrow (BM) to generate hematopoietic progenitor cells for therapeutic purposes. Pluripotency and undifferentiated stage were confirmed using molecular cell surface markers. Normal karyotype of these cell lines was confirmed. Here we demonstrate that SCNT-h-ESCs differentiate to hematopoietic precursors when cocultured with unmodified, nonirradiated donor BM. We did not use any xenogeneic material for this hematopoietic differentiation. Hematopoietic precursors derived from them expressed cell surface antigens CD45/34. When further cultured with hematopoietic growth factors these hematopoietic precursors formed characteristic myeloid, erythroid, and megakaryocyte lineages. Phenotypic CD34+ cells derived from NT-h-ESCs were functionally similar to their counterparts in primary hematopoietic tissues like BM, umbilical cord, and blood. More terminally differentiated hematopoietic cells derived from h-ESCs under these culture conditions also expressed normal surface antigens like glycophorin A on erythroid cells, CD15 on myeloid cells, and CD41 on megakaryocytes. We report generation of hematopoietic progenitor cells from h-ESC lines by a SCNT technique, with differentiation into further lineages with structural and functional similarities to their adult counterparts in vivo. This novel alternative source of CD34+ stem cells from h-ESC lines generated without any xenogeneic material might be used to create transplantation tolerance, to implement regenerative medicine, and to treat autoimmune disorders.

Hematopoietic stem cell transplantation in autoimmune diseases: the Ahmedabad experience.

INTRODUCTION: Autoimmune disease represents a (AD) breakdown of natural tolerance against autoreactive antigens leading to a high mortality and morbidity. The reaction is usually polyclonal; T- and B-cell components of the hematopoietic system are responsible for disease progression. Allogeneic/autologous hematopoietic stem cell transplantation (HSCT) are the current modalities for treating drug-resistant AD. PATIENTS AND METHODS: We present a single-center retrospective evaluation of allogeneic HSCT with nonmyeloablative, low-intensity conditioning in nine patients (five males, four females) with pemphigus vulgaris (PV) and 27 patients with systemic lupus erythematosus (SLE; 3 males, 24 females). The mean follow-up period was 4.24 years for PV and 4.9 years for SLE. Cytokine-mobilized HSC from unmatched related donors, with mean dose of 21.3 x 10(8) nucleated cells/kg body weight (BW; mean CD34(+) count, 6 x 10(6)/kg BW) was administered in to the thymus as well as the portal and peripheral circulations of recipients. Cyclosporine (4 +/- 1 mg/kg BW per day) and prednisolone (10 mg/kg BW per day) were administered for 6 months to protect mixed chimerism. A subset of patients with cross-gender donors were analyzed for peripheral blood chimerism at 1 month post-HSCT and every 3 months thereafter. RESULTS: Sustained clinical remission with peripheral lymphohematopoietic chimerism of 0.7 +/- 0.3% was observed in PV, whereas SLE relapsed after mean of 7.35 months of disease-free interval associated with fall in chimerism from 5 +/- 3% to < or =0.08 +/- 0.03%. CONCLUSION: HSCT was effective to achieve early clinical remission of PV; and in SLE relapsed after a 7.35-month disease-free interval accompanied by a fall in mixed lymphohematopoietic chimerism.

Cadaveric renal transplantation: our experience at the Institute of Kidney Diseases & Research Centre, Institute of Transplantation Sciences, Ahmedabad.

In a developing country such as India, cadaveric renal transplantation accounts for only less than 1% of total renal transplantations. The reasons for such a low rate of cadaveric transplantation are many, ranging from lack of awareness to socioeconomic reasons. Our institute conducted a statewide public awareness program and initiated an intercity organ harvesting program. This doubled the cadaveric renal transplantations in the last 2 years. We performed 38 cadaveric transplantations among 190 renal transplantations in the last year (August 2005 to July 2006). We retrieved kidneys from 21 donors, of whom 9 were outside our city. From 21 donors we transplanted 38 recipients; out of whom 3 received dual kidneys and one kidney was discarded. The Mean age of the donors was 41.4 +/- 18.2 years with a mean cold ischemia time of 6.9 +/- 3.8 hours. Sixty-eight percent had delayed graft function. At the last follow-up, which was 190 +/- 98 days, patient survival rate was 90%: 4 patients died, including 2 due to bacterial sepsis and 2 due to cytomegalovirus (CMV) disease. The Graft survival rate was 85%, and the death-censored graft survival rate was 90%. Mean serum creatinine value at the last follow-up was 1.2 +/- 0.3 mg%. There were 5 episodes of acute rejection in 31 patients during first 3 months (16% acute rejection rate). The increase in cadaveric transplantations was associated with satisfactory patient and graft survival despite the high incidence of delayed graft function.

Embryonic stem cell derived and adult hematopoietic stem cell transplantation for tolerance induction in a renal allograft recipient:--a case report.

UNLABELLED: We generated an human embryonic stem cell (hESC) line to augment chimerism-associated tolerance. A 40-year-old African with chronic glomerulonephritis-chronic renal failure with 100% G6PD enzyme deficiency presented for renal transplantation with a 27-year-old, 6/6 HLA-matched sister as a willing donor. METHOD: We generated an hESC line from the donor's oocytes using long ovarian stimulation protocol simultaneously with tolerance induction protocol. A nuclear transfer (NT)-hESC line was derived by transferring a donor cumulus cell into an enucleated oocyte, subjected to electrical fusion, and cultured for 5 days. ESCs hatched from the blastocyst on day 6 were cocultured with her unmodified bone marrow for 2 days and suspended in Ringer's lactate. Five milliliters of suspension were collected for cell counting, viability, pluripotency, flow cytometry, and karyotyping. The remaining suspension was infused into the periphery of the recipient. Transplantation was performed 1 week later following a negative lymphocytotoxicity cross-match test using no immunosuppression. Peripheral blood chimerism (PBC) was studied using fluorescent in situ hybridization technique. Allograft biopsy was performed on day 7. RESULTS: NT-hESC CD34+ count was 7.6%, viability 100%, karyotyping normal, pluripotency markers: SSEA-1, SSEA-4, OCT-3/4, TRA-1/60:positive; 12% PBC was noted at 1 week after transplantation. Serum creatinine was 1.2 mg%, graft biopsy was unremarkable, and G6PD enzyme deficiency was corrected to 0% at 100 days posttransplant. Liver function tests and hematology profile were unremarkable for graft-versus-host disease. CONCLUSION: This is the first report of tolerance induction using NT-hESC-induced hematopoietic chimerism with synergistic use of adult bone marrow. It was safe and effective.

Allogeneic hematopoietic stem-cell transplantation, mixed chimerism, and tolerance in living related donor renal allograft recipients.

OBJECTIVE: We designed a prospective, randomized, and controlled clinical trial to evaluate the efficacy and safety of achieving a mixed chimerism-associated tolerance protocol for recipients of living related donor (LRD) renal allografts. PATIENTS AND METHODS: Sixty-six consecutive patients were divided into two equal groups of 33 patients with end-stage renal disease. They were enrolled for transplantation after negative lymphocytotoxicity cross-matching (LCM). Both groups (treated [Tn] and control [Cn]) showed similar clinical and laboratory parameters and donor HLA match profiles. The Tn group underwent thymic transplantation of donor renal tissue, two donor-specific transfusions, low-intensity conditioning, and high-dose hematopoietic stem-cell transplantation (HSCT) before renal transplantation. The conditioning regimen included low-dose, target-specific irradiation (to abdominal and inguinal lymph nodes, bone marrow [BM] from thoracolumbar vertebrae and part of the pelvis on alternate days, 100 rad x 4), anti-T-cell antibodies (1.5 mg/kg body weight [BW]), cyclophosphamide (10 mg/kg BW x 2 consecutive days), and cyclosporine (CyA; >3 mg/kg BW/d). Unfractionated HSCT procured from the donor marrow was administered into the BM, portal and peripheral circulations, within 24 hours of achieving CD 4+/CD 8+ T-cell count less than 10% of normal. This infusion was supplemented with a dose of peripherally mobilized stem cells (mean total dose of 20 x 10(8) cells/kg recipient BW) administered peripherally. Renal transplantation was performed after negative LCM. Donor-specific cytotoxic antibodies were eliminated with intravenous immunoglobulins and plasmapheresis before renal transplantation. Mixed chimerism was evaluated before and after transplantation at monthly intervals in patients with donors of opposite gender by the FISH technique. Both groups received CyA and prednisolone for immunosuppression; Cn subjects also received mycophenolate mofetil/azathioprine. Rejection was treated with standard treatment. Immunosuppression was withdrawn 6 months after renal transplantation for patients with consistently positive chimerism. Clinical tolerance was defined as stable allograft function for more than 100 days without immunosuppression and confirmed by allograft biopsy. RESULTS: Over a mean follow-up of 210 days, all Tn patients showed stable allograft function with mean serum creatinines (SCr) of 1.20 mg/dL, no rejection/CMV infections/graft or patient loss. A low-level donor-specific cytotoxic antibody was observed in all Tn patients. The CyA toxicity was noted in 10 (30.3%) patients. Persistent mixed hematopoietic chimerism was seen in all 21 patients irrespective of donor-recipient HLA matching (mean 0.5% before and 1 +/- 0.3% after transplantation). All four patients on drug withdrawal have shown donor-specific tolerance at a mean follow-up of 129.8 days. Other Tn patients are in the process of being weaned off immunosuppression. Mean SCr of controls was 1.45 mg/dL over a mean follow-up of 216 days. Acute rejection was observed in 17 (51.5%) patients; no CMV infection/patient loss was noted and one (3.03%) graft was lost in controls. No patient was lost in controls. No graft-versus-host disease was observed in Tn patients. CONCLUSION: We have achieved mixed hematopoietic chimerism-associated tolerance with high-dose HSCT, intrathymic donor renal tissue transplantation, and minimal conditioning without any adverse effects.

Effect of Co substitution on the magnetic and electron-transport properties of Mn2PtSn.

The structural, magnetic and electron-transport properties of Mn(2)Pt(1-x)Co(x)Sn(x = 0, 0.3, 0.5, 0.7, 1) ribbons prepared by arc-melting and melt-spinning were investigated. The rapidly quenched alloys with x = 0 and 0.3 were found to crystallize in the inverse tetragonal structure, but the structure transformed into inverse cubic as x increased to 0.5. At room temperature, the samples are ferro or ferrimagnetic, and the Curie temperature increases by 225 K from 370 K for Mn(2)PtSn (x = 0) to 595 K for Mn(2)CoSn (x = 1). The measured anisotropy constants for the inverse-tetragonal alloys are on the order of 1 Merg cm(-3) at room temperature. The ribbons are moderately conducting with the room temperature resistivities being between 0.4 and 8.4 mΩ cm. Interestingly, the thermal coefficient of resistivity transforms from positive to negative and the magnetoresistance transforms from negative to positive as the value of x reaches 0.5.

Oral absolute bioavailability and intravenous dose-proportionality of cefprozil in humans.

The absolute bioavailability (F) and dose proportionality of cefprozil were investigated in a parallel design study with an embedded two-way crossover leg. Twenty-four healthy male subjects divided into 3 dosing groups received a single 250-, 500-, or 1000-mg dose of cefprozil by a 30-minute intravenous infusion. Subjects assigned to the 500-mg dose group also received a 500-mg oral dose of cefprozil in crossover manner with a wash-out period of 7 days between each treatment. Cefprozil consists of cis and trans isomers in an approximate 90:10 ratio. Serial blood and urine samples were collected and analyzed for the concentrations of the cis and trans isomers of the cephalosporin using high-pressure liquid chromatographic assay with UV detection methods. After the 250-, 500-, and 1000-mg intravenous administration of cefprozil, the peak concentrations were 13.2, 26.0, and 48.5 micrograms/mL, and area under the plasma concentration versus time profiles were 17.2, 31.4, and 58.1 micrograms.hour/mL, respectively, for the cis isomer increasing in a dose proportional manner. Total body clearance, renal clearance, and volume of distribution at steady state, adjusted for body weight, were not significantly different among all groups. Mean residence time, elimination half-life, and urinary recovery were invariant with the dose. Based on the plasma and urine data, the estimates of F were 89% and 94% for the cis isomer, respectively. The plasma concentrations of the trans isomer were about 1/10th of the cis isomer, and all parameters were similar to those observed for the cis isomer. In summary, cefprozil exhibits linear pharmacokinetics and is essentially completely absorbed after oral administration.