An entrapped epidural catheter in a postpartum patient

BACKGROUND AND OBJECTIVES

Epidural catheters are seldom difficult to remove from patients. In fact, a review of the literature demonstrates only a few cases pertaining to epidurals and the unusual complication of catheter entrapment.

METHODS

This case report involves an uncomplicated obstetric patient who had an epidural placed for labor and in whom multiple attempts were needed to remove the catheter.

Hypersensitivity pneumonitis in a machinist

Hypersensitivity pneumonitis (HP), or extrinsic allergic alveolitis, is a patchy, interstitial lung disease that involves an immunologic reaction of the lung to repeated inhalation of foreign antigens. In this report, we describe a machinist with exposure to metalworking fluids (MWFs) and biopsy-confirmed HP. Return to work, which could be equated with a retrospective workplace-specific bronchoprovocation test, proved that working within an environment in which MWFs were used was associated with clinical deterioration in the patient's pulmonary status and with clinical improvement after removal from exposure.

CD6+ T cell-depleted allogeneic bone marrow transplantation for non-Hodgkin's lymphoma

For patients with non-Hodgkin's lymphoma (NHL) undergoing blood or bone marrow transplantation (BMT), the use of autologous grafts has often been preferred to that of allogeneic stem cells because of a significantly lower incidence of non-relapse mortality. If complications associated with allo-BMT could be minimized without compromising efficacy, then it might become a preferred strategy for certain subsets of patients. In this report, we describe the toxicity and long-term efficacy of T cell-depleted allogeneic BMT using anti-CD6 monoclonal antibody and complement alone to reduce the risk of GVHD and its sequelae. Twenty-two patients, aged 18-60 years, with high (n = 10), intermediate (n = 9), or low (n = 3) grade NHL underwent HLA-identical allogeneic BMT from siblings. Patients had either relapsed after at least one remission or never achieved a full remission with chemotherapy. Twenty patients had a history of marrow involvement. Bone marrow was depleted of CD6+ T cells with T12 monoclonal antibody and complement as the sole form of GVHD prophylaxis. Stable hematopoietic engraftment occurred in all 22 patients. Four patients developed grade 2 and 1 patient grade 3 GVHD (23% grades 2-4 GVHD). Chronic GVHD has occurred in three patients. Treatment-related mortality was very low. Only one patient died while in remission. Thirteen patients are alive and free of disease with a median follow-up of 30 months. Estimated event-free and overall survivals are 54 and 59%, respectively. CD6 allogeneic marrow transplantation is associated with a low risk of transplant-related complications and may offer advantages for certain patients with recurrent NHL felt to be at high risk for relapse after autologous transplantation.

In vivo relaxation time measurements in the human placenta using echo planar imaging at 0.5 T

This paper presents the first in vivo measurements of the nuclear magnetic resonance relaxation times T1 and T2 at 0.5 T in the human placenta from 20 weeks gestational age until term, in both normal and compromised pregnancies. T1 measurements were performed by using both an inversion recovery sequence and the Look-Locher echo planar imaging (EPI) sequence on a total of 41 women with normal pregnancies and 11 women with compromised pregnancies. T2 measurements were performed by using a spin-echo EPI sequence on 36 women with normal pregnancies and 14 women with compromised pregnancies. In normal pregnancies, both the T1 values measured with the inversion recovery sequence and the T2 values were found to decrease with gestational age, the linear regression results gave T1 = -9.1t + 1538 r2 = 0.23 p = 0.03. T2 = -4.0t + 338 r2=0.47 p =410(-6) where t is the gestational age in weeks, and T1 and T2 are the relaxation times in milliseconds. T1 values measured very rapidly with the Look-Locher EPI sequence, but, therefore, with a much lower signal-to-noise ratio, showed no significant trends. The T1 values measured in the abnormal group were significantly lower than those measured in the normal group. Four out of eight patients with compromised pregnancies had placental T1 values lying outside the 90% confidence limits for the normal population based about the regression line, significantly more than expected by chance (p = 0.005). Ten out of fourteen of the T2 measurements in the abnormal group were below the regression line established for the normal group, with 4 lying below the 90% confidence interval, although these trends were only just significant (p = 0.06 and p = 0.03).

Adhesion formation after intraperitoneal and extraperitoneal implantation of polypropylene mesh

Polypropylene mesh is commonly used in open and laparoscopic hernia repairs. We tested the hypothesis that intra-abdominal adhesion formation secondary to polypropylene mesh is greater when mesh is placed in an intraperitoneal versus an extraperitoneal position. Fifty adult male rats underwent midline laparotomy with or without implantation of a nonabsorbable mesh. There were ten rats in each of the following five groups: EP-M, creation of an extraperitoneal pocket without mesh placement; EP+M, mesh placement in an extraperitoneal pocket; IP+M, intraperitoneal mesh; IT-M, creation of an abdominal wall ischemic defect without mesh placement; IT+M, ischemic defect plus mesh. Adhesion formation was graded on a scale of 0 to 5, 2 weeks after operation. All groups formed adhesions. Tissue injury or the placement of a mesh in an intraperitoneal position resulted in significantly more adhesions. An entirely extraperitoneal approach to mesh placement is needed to minimize adhesions after laparoscopic hernia repair.

A comparative study of the long term psychosocial functioning of childhood acute lymphoblastic leukemia survivors treated by intrathecal methotrexate with or without cranial radiation

BACKGROUND

Although previous research has delineated medical, cognitive, and neuropsychologic late effects of central nervous system (CNS) prophylaxis for childhood acute lymphoblastic leukemia (ALL), it has been difficult to draw conclusions about the long term psychosocial sequelae of these treatments due to methodologic problems that led to inconclusive results in past studies. In the current study, the authors examined the long term psychosocial functioning of childhood ALL survivors who had been treated on a Phase III clinical protocol (Cancer and Leukemia Group B [CALGB] 7611) between 1976 and 1979, in which they were randomized to receive either 2400 centigray of cranial radiation (CRT) with intrathecal methotrexate (IT-MTX) or intermediate dose systemic methotrexate (IV-MTX) with IT-MTX.

METHODS

One hundred ten survivors of childhood ALL (mean age, 20.8 years) treated on CALGB 7611 who were age 14 years or older and disease free for at least 1 year were studied a mean of 14.7 years after their entry on CALGB 7611. In a telephone interview, a psychosocial assessment battery was administered to the patients, consisting of measures that assessed psychologic, sexual, social, and vocational functioning as well as any delayed physical effects.

RESULTS

Survivors who had received CRT + IT-MTX had significantly poorer academic achievement (P = 0.0001), poorer self-images with regard to their bodies (P = 0.001), and greater psychologic distress (P = 0.005).

CONCLUSIONS

Cranial radiation used to treat children with ALL has significant long term sequelae in terms of poorer academic achievement and psychosocial functioning. These data add weight to the conclusion that CRT prophylaxis should only be used to treat children who are at high risk of CNS relapse.

Parallel processing streams in human visual cortex

This study shows the existence in humans of independent neural processing streams in early visual cortex, which had previously been demonstrated in macaque monkeys. This evidence was obtained by controlled fixation testing of a subject who had suffered a small stroke in the right fusiform gyrus. The patient showed a severe disruption of color perception, shape discrimination and contrast sensitivity for stationary gratings in the upper left quadrant of his visual field. However, motion perception and contrast sensitivity for drifting gratings were relatively preserved. These results support the view that there are independent visual processing streams early in human visual cortex, and that these streams may subserve such functions as motion and color/form perception.

Relationship between muscle tone changes, sawtooth waves and rapid eye movements during sleep

'Sawtoothed' waves occur during rapid eye movement (REM) sleep, but their source as well as their function is not known. We studied the onset of sawtooth waves (STW) in relation to the onset of muscle tone reduction (MTR) and to REM during 20 polysomnographic recordings in 11 normal volunteers. Seventy-seven (85%) of a total of 91 REM sleep cycles were used for further analysis, because within a 1000 s interval they showed a relatively stereotyped sequence of events: a generalized body movement, followed by MTR, then the appearance of STW, and ending with the first REM. The first STW often occurred during the electrographic stage II period prior to the beginning of the REM, by which time muscle tone was either already at or close to the tone level of the REM sleep period in all subjects. The overall mean onset time of MTR was 267 s (range 89-660 s), STW was 378 s (range 169-779), and REM was 448 s (range 265-849); their differences were highly significant (F = 27.1, df 2,20, P < 0.001). Our data suggest that a predictable sequence of muscle tone reduction, then STW, and then REM, precedes the generally accepted onset of the REM sleep period, and may have implications for the redesignation of physiologic REM sleep onset.

Pharmacokinetics and bioavailability of montelukast sodium (MK-0476) in healthy young and elderly volunteers

A study was conducted to (i) characterize the multiple-dose pharmacokinetics of oral montelukast sodium (MK-0476), 10 mg d-1 in healthy young subjects (N = 12), (ii) evaluate the pharmacokinetics of montelukast in healthy elderly subjects (N = 12), and (iii) compare the pharmacokinetics and oral bioavailability of montelukast between elderly and young subjects. Following oral administration of montelukast sodium, 10 mg d-1 (the therapeutic regimen for montelukast sodium) for 7 d, there was little difference in the plasma concentration-time profiles of montelukast in young subjects between day 1 and day 7 dosing. On average, trough plasma concentrations of montelukast were nearly constant, ranging from 18 to 24 ng mL-1 on days 3-7, indicating that the steady state of montelukast was attained on day 2. The mean accumulation ratio was 1.14, indicating that this dose regimen results in a 14% accumulation of montelukast. In elderly subjects, mean values of plasma clearance (Cl), steady-state volume of distribution (Vss), plasma terminal half-life (t1/2), and mean residence time in the body (MRTIV) following a 7 mg intravenous (5 min infusion) administration of montelukast sodium in the elderly were 30.8 mL min-1, 9.7 L, 6.7 h, and 5.4 h, respectively. Following a 10 mg oral dose, the bioavailability of montelukast in healthy elderly averaged 61%, very close to that (62%) determined previously in healthy young subjects. Also following the 10 mg oral administration, the mean values of AUC0-->infinity, Cmax, tmax, and t1/2, and the mean plasma concentration-time profile of montelukast in the elderly, were generally similar to those in young subjects, indicating that age has little or no effect on the pharmacokinetics of montelukast. There is no need to modify dosage as a function of age.

Metabolic profiles of montelukast sodium (Singulair), a potent cysteinyl leukotriene1 receptor antagonist, in human plasma and bile

Montelukast sodium [1-([(1(R)-(3-(2-(7-chloro-2-quinolinyl)-(E)- ethenyl)phenyl)-3-(2-(1-hydroxy-1-methylethyl)phenyl)propyl)thio]methyl)cyclopropylacetic acid sodium salt] (MK-476, Singulair) is a potent and selective antagonist of the cysteinyl leukotriene (Cys-LT1) receptor and is under investigation for the treatment of bronchial asthma. To assess the metabolism and excretion of montelukast, six healthy subjects received single oral doses of 102 mg of [14C]montelukast, and the urine and feces were collected. Most of the radioactivity was recovered in feces, with </=0.2% appearing in urine. Based on these results and the reported modestly high oral bioavailability of montelukast, it could be concluded that a major part of the radioactivity was excreted via bile. A second clinical study was conducted to identify biliary metabolites of montelukast. The bile was aspirated using a modified procedure involving a nasogastric tube placed fluoroscopically near the ampulla of Vater, after an oral dose of 54.8 mg of [14C]montelukast. This technique appears to be a new application for drug metabolism studies. The study was conducted with fasted and nonfasted subjects, with the bile being aspirated continuously under suction over periods of 2-8 hr and 8-12 hr after the dose, respectively. Two hours before the end of the collection procedure, cholecystokinin carboxyl-terminal octapeptide was administered iv to stimulate gallbladder contraction. Plasma samples also were collected periodically over 10 hr. Due to the nature of the collection procedure and the limited sampling time, recovery of radioactivity in bile was incomplete and varied from 3 to 20% of the dose. Radiochromatographic and LC-MS/MS analyses of bile showed the presence of one major and several minor metabolites, along with small amounts of unchanged parent drug. The minor metabolites were identified, by LC-MS/MS comparison with synthetic standards or by NMR, as acyl glucuronide (M1), sulfoxide (M2), 25-hydroxy (a phenol, M3), 21-hydroxy (diastereomers of a benzylic alcohol, M5a and M5b), and 36-hydroxy (diastereomers of a methyl alcohol, M6a and M6b) analogs of montelukast. The major metabolite was characterized as a dicarboxylic acid (M4), a product of further oxidation of the hydroxymethyl metabolite M6. Chiral LC-MS/MS analyses of M4 revealed that this diacid, like M5 and M6, was formed in both diastereomeric forms. The levels of metabolites in the systemic circulation were low in the fed as well as fasted subjects, with <2% of the circulating radioactivity being due to metabolites M5a, M5b, M6a, and M6b. Overall, this bile aspiration technique, which is less invasive than either T-tube drainage or fine-needle percutaneous puncture, provided a convenient and expedient means of identifying the biliary metabolites of montelukast, relatively free of contributions from colonic microflora.

In vivo adsorption of isohemagglutinins with fresh frozen plasma in major ABO-incompatible bone marrow transplantation

Despite techniques to deplete red cells from major ABO-incompatible allogeneic bone marrow (BM) or to remove recipient isohemagglutinins (IHGs) before transplantation, delayed erythropoiesis and hemolysis, red cell aplasia, and increased red cell transfusion requirements may occur. Twenty-nine recipients of major ABO-incompatible allografts received donor-type frozen fresh plasma (FFP) infusions twice daily to adsorb IHGs in vivo. Engraftment and transfusion requirements were compared between the 29 FFP-treated major ABO-incompatible allograft recipients, 5 recipients of major ABO-incompatible BM who did not receive FFP infusions, 35 recipients of minor ABO-incompatible BM, and 172 recipients of ABO-compatible BM. No significant differences in either transfusion requirements or engraftment were seen in the FFP-treated major ABO-incompatible vs. minor ABO-incompatible or ABO-compatible groups (p values > or = 0.10). The infusion of donor-type FFP represents a simple, effective treatment strategy to neutralize IHGs and to prevent adverse consequences of major ABO incompatibility in the setting of allogeneic BM transplantation. The role of this strategy in the care of patients receiving ABO-incompatible solid organs remains to be defined.

Effect of stereotaxic intrastriatal cografts of autologous adrenal medulla and peripheral nerve in Parkinson's disease: two-year follow-up study

Studies in nonhuman primates with experimental parkinsonism have shown that intrastriatal cografts of autologous adrenal medulla and peripheral nerve yield greater behavioral improvement and graft survival than do adrenal medulla grafts alone. To test these observations, five patients with advanced Parkinson's disease were selected to receive unilateral intrastriatal adrenal medulla-intercostal nerve cografts. They were evaluated using the Core Assessment Program for Intracerebral Transplantation (CAPIT) protocol. Three of these patients also underwent quantitative motor testing for the measurement of upper limb bradykinesia (movement time; MT). Following right flank adrenalectomy, cografts consisting of small fragments of adrenal medullary tissue and minced intercostal nerve were stereotaxically implanted into three targets in the right striatum using computerized tomography guidance. Surgery was uneventful and postoperative magnetic resonance imaging revealed accurate placement of the grafts. No morbidity was encountered. Results of 24 months of clinical and quantitative motor assessments postoperatively are reported. Total UPDRS motor scores in the "off" state improved from a mean preoperative score of 39.5 to 32.1 at 3, 29.7 at 6, 27.6 at 9, 28.5 at 12, 31.4 at 18, and 26.5 at 24 months after surgery. Total timed motor test scores during the "off" state improved 17.9% at 6, 23.3% at 9, 18.2% at 12, 38.2% at 18, and 34.9% at 24 months postoperatively compared to baseline. Movement time showed statistically significant improvement (repeated measures ANOVA, P < 0.05) in the left arm (contralateral to surgery) in all three patients tested. These results indicate that stereotaxic intrastriatal implantation of autologous adrenal medulla-peripheral nerve cografts can be performed safely and clinical improvement from this procedure is sustained for a period of 24 months. The clinical improvement was paralleled by improvement in objective, quantitative motor testing.

CD6-depleted allogeneic bone marrow transplantation for acute leukemia in first complete remission

The appropriate timing of bone marrow transplantation (BMT) for adults with acute myelogenous leukemia (AML) and acute lymphoblastic leukemia (ALL) is controversial. Although allogeneic transplantation results in a lower risk of disease recurrence than intensive chemotherapy alone, overall outcome following BMT may not be improved due to the higher incidence of therapy-related fatal complications, frequently as a result of the development of graft-versus-host disease (GVHD). Selective T-cell depletion of donor marrow can reduce the incidence of GVHD and thereby limit transplant-related toxicity. Herein we report the risk of GVHD, incidence of transplant related mortality (TRM), likelihood of disease relapse, and overall survival in adult patients undergoing BMT with CD6 depleted allogeneic marrow for acute leukemia in first remission. Forty-one consecutive allogeneic transplants were performed on patients with acute leukemia and high-risk features (28 AML, 13 ALL) using T12 monoclonal antibody and complement to remove CD6+ T cells from donor marrow. No pre- or posttransplant immune suppressive medications for GVHD prophylaxis were administered. The actuarial estimated risk of grade 2 to 4 acute GVHD was 15% in patients receiving HLA identical grafts. Chronic GVHD developed in five patients. The estimated risk of TRM for patients in first complete remission was 5% at Day +100 and 16% at 2 years. Fatalities attributable to infection with cytomegalovirus or Epstein-Barr virus occurred in only three patients. Estimated probabilities of relapse, overall survival, and event-free survival at 4 years were 25%, 71%, and 63%, respectively. No significant differences in GVHD, TRM, relapse rate, or survival was observed for patients with AML compared with those with ALL. Allogeneic transplantation with CD6 depleted bone marrow is effective in consolidating remissions of high-risk patients with acute leukemia in first remission without excessive toxicity.

CD6+ T cell depleted allogeneic bone marrow transplantation from genotypically HLA nonidentical related donors

The widespread use of allogeneic bone marrow transplantation (BMT) is limited by the availability of suitable donors. Recent attempts to expand the donor pool by employing HLA matched unrelated marrow have been partially successful. However, severe graft-versus-host disease (GVHD) and graft failure remain obstacles and contribute to the substantial morbidity and mortality associated with matched unrelated BMT. The use of genotypically nonidentical related or unrelated donor marrow could have wider application if problems associated with GVHD could be overcome. Based upon the low incidence of GVHD in recipients of HLA-matched related donor marrow depleted of T cells with T12, an anti-CD6 monoclonal antibody, we applied this approach to 27 adult recipients of HLA mismatched related bone marrow. Ten patients received marrow mismatched at 2 HLA loci, 13 received 1 antigen mismatched marrow, and 4 received phenotypically identical marrow from a non-sibling. Immediately prior to admission, patients were treated with total lymphoid irradiation (750-1050 cGy) to suppress host derived. T lymphocytes capable of mediating graft rejection. The ablative regimen consisted of cyclophosphamide (60 mg/kg x 2 days) followed by total body irradiation (1400 cGy in 7 fractions over 4 days). Patients then received marrow depleted of T cells with T12 (CD6) plus complement. No immune suppressive medications were administered to prevent GVHD. Twenty-four of 27 patients displayed stable hematologic engraftment, achieving an absolute neutrophil count of 0.5 x 10(9)/L at a median of 19 days post-BMT. Degree of HLA disparity did not influence engraftment. Among engrafting patients, grades 2-4 acute GVHD occurred in 40% and grade 3-4 GVHD in 8%. Chronic GVHD developed in 5 patients. Patients mismatched at 2 loci were more likely to develop GVHD than those mismatched at 0-1 loci (logrank, p = .04). Disease relapse has occurred in only 3 patients receiving mismatched marrow. Estimated overall survival for mismatched patients is 56% at 2 years and is independent of HLA disparity. Among the patients transplanted for chronic myelogenous in stable phase or acute leukemia in first remission, estimated event free survival is 69% at 2 years compared to 20% for patients with more advanced disease. Our results suggest that transplantation of mismatched related marrow using modalities designed to reduce GVHD without immune suppressive medication (CD6 depletion) is feasible and should prompt wider investigation into the extended families of patients in the search for potential marrow donors. This approach also merits investigation in recipients of matched unrelated marrow as a potential means of reducing transplant-related toxicity.

5-HT3 receptor antagonists in the control of cisplatin-induced delayed emesis

Two large randomized, double-blind, placebo-controlled studies with an appropriate study design have been conducted to fully evaluate the efficacy of ondansetron in the control of cisplatin-induced delayed emesis. These studies show that ondansetron and particularly ondansetron plus dexamethasone have moderate efficacy in the control of cisplatin-induced delayed emesis and nausea. The benefit of ondansetron, with or without dexamethasone, may be greatest in patients with incomplete control of acute emesis. The efficacy of ondansetron in this setting compared to its greater efficacy during the acute phase of emesis induced by cisplatin and the more prolonged phases of acute emesis induced by cyclophosphamide and carboplatin indicates that non-5-HT3-mediated emetic mechanisms maybe are relatively more important in the delayed phase of emesis following cisplatin.

Alendronate stimulation of nocturnal parathyroid hormone secretion: a mechanism to explain the continued improvement in bone mineral density accompanying alendronate therapy

The major effect of currently available antiresorptive therapy for osteoporosis is to slow or arrest bone loss. Although antiresorptive therapies demonstrate increases in bone mineral density, the effect is usually transient, and a plateau in bone mineral density usually emerges at 1 year. A unique and unexplained feature of treatment with the antiresorptive agent alendronate is continued, and steady improvement in bone mineral density occurs in years 2 and 3. We postulated that a potential mechanism for this unanticipated effect might be an exaggerated nocturnal increase in parathyroid hormone (PTH), which can act as an anabolic agent. We examined day-night levels and diurnal variation of PTH, serum calcium, ionized calcium, and markers of bone formation (osteocalcin) and resorption (N-telopeptide cross-links) over 24 hours in a randomly selected subset of 38 women (placebo: N = 13; mean age +/- SD, 69 +/- 3 years; alendronate: N = 25; mean age +/- SD, 69 +/- 3 years) who had completed 12 to 15 months of a larger (N = 120), randomized, double-blind, placebo-controlled trial with alendronate, 5 mg/day. By month 12, increases in the bone density of the spine (4.6%) and femoral neck (2.7%) were observed in the group treated with alendronate compared with placebo, (spine, 2.2%, p = .05; femoral neck, -0.2%, p < or = .05). Mean nocturnal PTH (10 PM-8 AM) was 21% higher (39 versus 32 pg/ml), and nocturnal serum calcium averaged 3% lower (8.7 versus 9.0 mg/dL) in the alendronate-versus-placebo group (both p < or = .05). Daytime levels (8 AM-10 PM) of PTH did not differ significantly between groups. We observed accompanying decreases in coupled markers of bone formation (osteocalcin, 38% lower, p < or = .01) and resorption (N-telopeptide cross-links, 50% lower, p < or = .01) in the alendronate group. Significant diurnal variations of PTH, serum calcium, and osteocalcin were present in both groups. We conclude that following 1 year of alendronate therapy, women have significant increases in bone mineral density and in nocturnal PTH levels, associated with decreases in nocturnal serum calcium and markers of bone turnover with maintenance of the diurnal variation. The nocturnal increase in PTH may mimic the anabolic effect of low-dose intermittent PTH administration to stimulate bone formation. Therefore, the increase might be a potential mechanism to explain the continued improvement in bone density following more than 1 year of alendronate therapy.

Studies of the oral bioavailability of alendronate

Clinical studies were performed to examine the oral bioavailability of alendronate (4-amino-1-hydroxy-butylidene-1,1-bisphosphonate monosodium). All studies, with the exception of one performed in men, involved postmenopausal women. Short-term (24 to 36 hours) urinary recovery of alendronate after an intravenous dose of 125 to 250 micrograms averaged about 40% in both men and women. In women, oral bioavailability of alendronate was independent of dose (5 to 80 mg) and averaged (90% confidence interval) 0.76% (0.58, 0.98) when taken with water in the fasting state, followed by a meal 2 hours later. Bioavailability was similar in men [0.59%, (0.43, 0.81)]. Taking alendronate either 60 or 30 minutes before a standardized breakfast reduced bioavailability by 40% relative to the 2-hour wait. Taking alendronate either concurrently with or 2 hours after breakfast drastically (> 85%) impaired availability. Black coffee or orange juice alone, when taken with the drug, also reduced bioavailability (approximately 60%). Increasing gastric pH, by infusion of ranitidine, was associated with a doubling of alendronate bioavailability. A practical dosing recommendation, derived from these findings and reflective of the long-term nature of therapy for a disease such as osteoporosis, is that patients take the drug with water after an overnight fast and at least 30 minutes before any other food or beverage.

Echo-planar magnetic resonance imaging to assess water volume in the distal small bowel

PURPOSE

Assessment of fluid volumes and flow through the small intestine has in the past only been possible by means of invasive intubation studies on human volunteers. Intubation very likely disturbs gut motility and stimulates secretion.

METHODS

The aim of this study was to utilise the new technique of echo-planar magnetic resonance imaging in order to non-invasively visualise the changing volume of water in the small intestinal lumen. 200 mls of test solution was ingested and water volume assessed using a multi-slice scanning technique on 3 separate days. The solutions were pure water, pure water plus 2.264 or 10 g of mannitol. These were taken on separate days by 8 healthy male volunteers. Regions of interest were constructed in the area of the lower pelvis excluding retroperitoneal structure.

RESULTS

The water content of the lower small intestine did not change significantly over the 4 hours after the control solution. By contrast after both mannitol solutions there was an increase in the amount of water in the distal intestine as assessed by the area under the curve of the volume time profile (Control 51 ml.h (SD +/- 47); mannitol 2.264 g/200 ml 72 ml.h (SD +/- 57); 10 g/200 ml mannitol 115 ml.h (SD +/- 56)). Page's L Trend test showed that the trend for the volume to increase with increasing mannitol concentration to be statistically significant at the 1% level (L = 108).

CONCLUSIONS

The study highlights the potential of echo-planar magnetic resonance imaging to visualise changes in gastrointestinal physiology in a noninvasive manner.

Sequence and analysis of the human ABL gene, the BCR gene, and regions involved in the Philadelphia chromosomal translocation

The complete human BCR gene (152-141 nt) on chromosome 22 and greater than 80% of the human ABL gene (179-512 nt) on chromosome 9 have been sequenced from mapped cosmid and plasmid clones via a shotgun strategy. Because these two chromosomes are translocated with breakpoints within the BCR and ABL genes in Philadelphia chromosome-positive leukemias, knowledge of these sequences also might provide insight into the validity of various theories of chromosomal rearrangements. Comparison of these genes with their cDNA sequences reveal the positions of 23 BCR exons and putative alternative BCR first and second exons, as well as the common ABL exons 2-11, respectively. Additionally, these regions include the alternative ABL first exons 1b and 1a, a new gene 5' to the first ABL exon, and an open reading frame with homology to an EST within the BCR fourth intron. Further analysis reveals an Alu homology of 38.83 and 39.35% for the BCR and ABL genes, respectively, with other repeat elements present to a lesser extent. Four new Philadelphia chromosome translocation breakpoints from chronic myelogenous leukemia patients also were sequenced, and the positions of these and several other previously sequenced breakpoints now have been mapped precisely, although no consistent breakpoint features immediately were apparent. Comparative analysis of genomic sequences encompassing the murine homologues to the human ABL exons 1b and 1a, as well as regions encompassing the ABL exons 2 and 3, reveals that although there is a high degree of homology in their corresponding exons and promoter regions, these two vertebrate species show a striking lack of homology outside these regions.

Randomized double-blind crossover ondansetron-dexamethasone versus ondansetron-placebo study for the treatment of chemotherapy-induced nausea and vomiting in pediatric patients with malignancies

PURPOSE

To determine whether the addition of dexamethasone to ondansetron (OND + DEX) is a more effective antiemetic regimen than ondansetron (OND) alone in children receiving chemotherapy.

PATIENTS AND METHODS

Children who had solid tumors and who were receiving highly emetogenic chemotherapy, including cisplatin, carboplatin, cyclophosphamide, and ifosfamide, were randomized (1:1) in a double-blind fashion to receive either OND 0.15 mg/kg intravenously (i.v.) 30 min before and 4 and 8 h after chemotherapy and placebo, or OND + DEX (same OND doses plus DEX 8 mg/m2 i.v. 30 min before chemotherapy, followed by 16 mg/m2 in divided doses) as antiemetics. The patients were crossed over to the other antiemetic regimen when receiving an identical course of chemotherapy. Patients were monitored for emetic episodes, nausea, appetite, sense of well-being, and antiemetic adverse events.

RESULTS

A total of 33 patients were evaluated. Sixty-one percent of the patients receiving OND + DEX regimens had a complete response for emetic episodes as compared with 23% with OND alone. Combined complete and major responses (two or less emetic episodes) were 86% for OND + DEX and 67% for OND. Failure for emetic episodes (more than five vomitings/day) were seen only in 7-10% of the total population. Minimal or no nausea was experienced in 74% of OND + DEX courses and in 52% of the OND courses. Appetite was better in OND + DEX courses (p = 0.006). Both antiemetic arms had similar adverse events. Mild to moderate sedation occurred in about half of the courses, followed by restlessness (29%), headache (17%), diarrhea (17%), and hiccups (2%).

CONCLUSION

The combination of ondansetron and dexamethasone is superior to ondansetron alone to control emetic episodes in children receiving highly emetogenic chemotherapy (p = 0.04).

Polyacrylamide-based redox polymer for connecting redox centers of enzymes to electrodes

Enzyme electrodes based on complexing a water-soluble copolymer of acrylamide and vinylimidazole with [Os(dmebpy)2C1]+/2+ (dmebpy = 4,4'-dimethyl-2,2'-bipyridine) and cross-linking with oxidases by water-soluble cross-linkers are described. The potential of the polyacrylamide-based redox polymer is +55 mV (SCE), a typical electron diffusion coefficient (De) in the redox hydrogel that results from its cross-linking is (1.3 +/- 0.1) x 10(-9) cm2/s. The properties of the enzyme electrodes formed when this redox hydrogel "wired" horseradish peroxidase (HRP), lactate oxidase (LOx) or glucose oxidase (GOx) depended on the thickness of the hydrogel film, the chemistry of their cross-linking, and their enzyme content. At the wired HRP electrodes, H2O2 was electrocatalytically reduced to water at 0.0 V (SCE). Lactate and glucose were electrocatalytically oxidized at 0.16 V (SCE). The GOx electrodes, when made with 140 micrograms/cm2 thick polymer films, were selective for glucose in the presence of physiological concentrations of urate and ascorbate.

Stabilization and surface modification of monoclonal antibodies by 'bi-layer encagement'

A two step simple procedure for antibody stabilization in soluble form was developed. The antibody is first treated with low molecular weight polyaldehyde (polyglutaraldehyde). Following removal of non-bound polyaldehyde the antibody-polyaldehyde conjugate is crosslinked by polyamine (alkyl amine derivative of polyglutaraldehyde). Feasibility studies were successfully conducted employing monoclonal antibody raised against horseradish peroxidase as model system. The stabilized antibody preparation exhibited improved thermal stability, enhanced resistance to proteolytic digestion and higher 'specific binding activity' in ELISA test, without losing its capability to bind large antigen (enzyme) or being recognized by another antibody (goat anti-mouse IgG).