Longitudinal aneurysm shrinkage following endovascular aortic aneurysm repair: a source of intermediate and late complications

PURPOSE

To report the incidence of delayed complications following endovascular abdominal aortic aneurysm (AAA) repair and the relationship of these sequelae to morphological changes in the sac and endograft.

METHODS

Twenty-six AAA patients treated with Vanguard endografts had completed > or = 1-year follow-up. Postoperative angiograms and spiral computed tomographic (CT) scans with 3-dimensional reconstruction were compared to the 1-year images to determine morphological changes in the aneurysm sac and the endograft. These changes were then related to complications occurring between 1 and 12 months postoperatively in the study group.

RESULTS

Comparison of angiograms uncovered endograft buckling in 18 (69%) patients and acutely angled or kinked endografts in 10 (38%). Measurements from the CT scans found that undistorted endografts had a mean change in sac length of +6.6 mm. Mean sac length change in buckled endografts was -3.1 mm, while kinked endografts displayed a mean change of -6.2 mm (p < 0.002, Student's t-test). Five (19%) patients, all with distorted endografts, demonstrated late (1 to 12 months) complications (4 endoleaks and 1 graft limb thrombosis) owing to component separation, distal stent migration, and acute angulation. No movement in the proximal stent was observed. Elongation of the endograft (flow line measurement) was observed in one tube graft only.

CONCLUSIONS

In this study, longitudinal shrinkage of the sac following endovascular aortic aneurysm repair led to buckling or kinking of the endograft within 1 year in 69% of patients. This appears to be an important source of delayed complications.

ICP-CBF trauma bolt, laboratory evaluation

Thermal diffusion flowmetry is a continuous quantitative technique of measuring regional cerebral blood flow utilizing a silastic strip probe placed through a craniotomy or craniectomy in the operating room. A new bolt like application of this technology is now available for commercial use and is especially designed for bedside placement in trauma patients. This new trauma bolt is tested in juvenile pigs who are subjected to episodes of hypercapnea to increase cerebral blood flow, and records significant changes in blood flow. Another feature of the trauma bolt is a second port for the placement of an intracranial pressure (ICP) monitor. Placement of the probe and ICP monitor were easier than with the silastic probe and had relatively little complication.

Color flow-directed Doppler studies of ovarian masses. Computer analysis

OBJECTIVE

To determine if analyzing the entire color Doppler image (CDI) pulse wave of an ovarian mass can improve the ability to predict its histopathology.

STUDY DESIGN

The CDI of 42 histopathologically diagnosed adnexal masses were retrospectively analyzed. Using an image analysis software program, the following parameters were calculated: area under the curve, compactness, Feret diameter, perimeter, shape factor and width of the waveform. Using an automated curve-fitting software program, the up and down slopes were processed separately for the optimal equation and coefficient for each slope. Two computerized neural networks were created, both consisting of an input layer, one hidden layer and an output layer of three neurons: benign, borderline and malignant. The first network contained two input neurons: pulsatility index (PI) and resistance index (RI). The second network contained 10 input neurons consistent with the shape and slope parameters calculated. The coefficient of determination (R2) was determined for each network.

RESULTS

The neural network utilizing RI and PI failed to train (1,397 runs, 67,056 facts, R2 = 0.59, 0.12 and 0.43 for benign, borderline and malignant masses, respectively). The network using the 10 calculated parameters achieved an R2 of 0.96 after 685 runs and 27 facts.

CONCLUSION

Analyzing the CDI studies of ovarian masses, using the entire pulse wave, improved the ability to differentiate between their benign, borderline and malignant histopathology.

Sry and the testis: molecular pathways of organogenesis

The gene Sry acts as a switch, initiating pathways leading to the differentiation of a testis rather than an ovary from the indifferent gonad (genital ridge) in mammals. The early events following Sry expression include rapid changes in the topographical organization of cells in the XY gonad. Sry must therefore initiate signaling pathways that direct male-specific patterns of proliferation, migration, cell-cell organization, and vascularization. We have identified an increase in male-specific proliferation by 12.0 days post coitum, while proliferation in the female gonad declines. We have also observed male-specific cell migration from the mesonephros into the gonad in a composite organ culture system in which gonads from wild-type mice (CD1) and mesonephroi from a transgenic strain expressing beta-galactosidase in all its cells (ROSA26) were grafted together in vitro at the indifferent stage of gonadogenesis. Migration depends on an active signal that requires the presence of a Y chromosome in the gonadal portion of the graft. The signals that trigger migration operate over considerable distances, suggesting either a long-range diffusible factor or the involvement of a rapid and efficient relay mechanism. Identification of the somatic cells contributed from the mesonephros with cell-specific markers indicated that some of the migrating cells were endothelial, revealing differences in processes of vascularization between male and female gonads. A second distinct population of migrating cells lay in close apposition to endothelial cells, and a third population occupied positions circumscribing areas of condensing Sertoli cells.

Control of cyclin B1 localization through regulated binding of the nuclear export factor CRM1

Activation of the Cyclin B/Cdc2 kinase complex triggers entry into mitosis in all eukaryotic cells. Cyclin B1 localization changes dramatically during the cell cycle, precipitously transiting from the cytoplasm to the nucleus at the beginning of mitosis. Presumably, this relocalization promotes the phosphorylation of nuclear targets critical for chromatin condensation and nuclear envelope breakdown. We show here that the previously characterized cytoplasmic retention sequence of Cyclin B1, responsible for its interphase cytoplasmic localization, is actually an autonomous nuclear export sequence, capable of directing nuclear export of a heterologous protein, and able to bind specifically to the recently identified export mediator, CRM1. We propose that the observed cytoplasmic localization of Cyclin B1 during interphase reflects the equilibrium between ongoing nuclear import and rapid CRM1-mediated export. In support of this hypothesis, we found that treatment of cells with leptomycin B, which disrupted Cyclin B1-CRM1 interactions, led to a marked nuclear accumulation of Cyclin B1. In mitosis, Cyclin B1 undergoes phosphorylation at several sites, a subset of which have been proposed to play a role in Cyclin B1 accumulation in the nucleus. Both CRM1 binding and the ability to direct nuclear export were affected by mutation of these phosphorylation sites; thus, we propose that Cyclin B1 phosphorylation at the G2/M transition prevents its interaction with CRM1, thereby reducing nuclear export and facilitating nuclear accumulation.

Connectivity and control in the year 2000 and beyond

By now, most executives are familiar with the famous Year 2000 problem--and many believe that their companies have the situation well in hand. After all, it seems to be such a trivial problem--computer software that interprets "oo" to be the year 1900 instead of the year 2000. And yet armies of computer professionals have been working on it--updating code in payroll systems, distribution systems, actuarial systems, sales-tracking systems, and the like. The problem is pervasive. Not only is it in your systems, it's in your suppliers' systems, your bankers' systems, and your customers' systems. It's embedded in chips that control elevators, automated teller machines, process-control equipment, and power grids. Already, a dried-food manufacturer destroyed millions of dollars of perfectly good product when a computer counted inventory marked with an expiration date of "oo" as nearly a hundred years old. And when managers of a sewage-control plant turned the clock to January I, 2000 on a computer system they thought had been fixed, raw sewage pumped directly into the harbor. It has become apparent that there will not be enough time to find and fix all of the problems by January I, 2000. And what good will it do if your computers work but they're connected with systems that don't? That is one of the questions Harvard Business School professor Richard Nolan asks in his introduction to HBR's Perspectives on the Year 2000 issue. How will you prepare your organization to respond when things start to go wrong? Fourteen commentators offer their ideas on how senior managers should think about connectivity and control in the year 2000 and beyond.

Do infants with cystic fibrosis need a protein hydrolysate formula? A prospective, randomized, comparative study

OBJECTIVES

We compared the nutritional benefits of a protein hydrolysate and a conventional infant formula in infants newly diagnosed with cystic fibrosis (CF).

STUDY DESIGN

Twenty-three infants with CF (<6 months of age) and pancreatic insufficiency were randomized to receive a hydrolysate formula (Alimentum) or a cow's milk-based formula (Similac). Each patient was monitored at 1 month and then every 3 months for 1 year.

RESULTS

Eighteen patients (8 Alimentum, 10 Similac) completed the study. At entry, the age distribution and clinical characteristics of each group were comparable. Energy intake with each formula was the same at 1 and 3 months, but at 6 and 12 months the hydrolysate-fed infants had higher age-adjusted energy intake. There were no differences in fecal energy or fecal fat at entry or throughout the study. Although the hydrolysate-fed infants were slightly more malnourished at diagnosis, growth velocity and nutritional status of infants with CF in each group were the same throughout the study.

CONCLUSIONS

The results of this randomized study fail to support the use of a hydrolyzed formula for the routine care of infants newly diagnosed with CF.

Occult deep venous thrombosis complicating superficial thrombophlebitis

PURPOSE

To determine whether superficial thrombophlebitis (STP) can extend into the deep venous system (DVS) and whether this may result in pulmonary embolization.

METHODS

All venous duplex ultrasound examinations performed in our vascular laboratory to rule out deep venous thrombosis from June 1, 1994, to June 24, 1996, were reviewed.

RESULTS

Of 8313 limbs studied by duplex scanning in 6148 patients, 1756 limbs (21.1%) had a positive result for deep venous thrombosis. STP was demonstrated in 232 limbs (213 patients), of which 20 (8.6%) extended into the DVS. Fourteen (70%) were noted on the initial scan, and six (30%) were detected on serial follow-up scans. Eighteen (90%) originated in the proximal greater saphenous vein and extended across the saphenofemoral junction into the common femoral vein. Nine demonstrated "free-floating" thrombus with a "tongue" extending into the common femoral vein while still attached proximally to the greater saphenous vein. Extension of thrombus from the lesser saphenous vein into the popliteal vein was noted in two cases (10%). One pulmonary embolization was directly observed to occur in real time during scanning. No pulmonary embolization was seen when STP did not involve the DVS.

CONCLUSIONS

STP can extend into the DVS. In this series STP of the proximal greater saphenous vein extended into the common femoral vein in 8.6% of the cases, of which 10% embolized to the lungs. When the DVS is involved, standard deep venous thrombosis treatment (heparin, warfarin, bed rest) should be instituted. We recommend duplex imaging for STP involving the greater saphenous vein in the thigh to rule out occult deep venous thrombosis. STP is not always benign and self-limiting as previously described.

Endoluminal repair of internal carotid artery aneurysm: a feasible but hazardous procedure

PURPOSE

The aim of this study was to report the repair of an aneurysm of the internal carotid artery using the endoluminal method.

METHODS

A 70-year-old male patient noted a swelling in the right side of his neck 22 years after endarterectomy of the right internal carotid artery. Duplex ultrasound confirmed the clinical diagnosis of aneurysm of the internal carotid artery. Further investigation included contrast-enhanced computed tomographic (CT) scanning and carotid angiography performed via a retrograde femoral approach. The aneurysm contained thrombus and was 3 cm in diameter and in length. It extended superiorly from a point 0.5 cm above the carotid bifurcation to a point estimated to be 2 cm from the base of the skull. Repair of the aneurysm was undertaken using the endoluminal method. A self-expanding endograft 8 mm in diameter and 4 cm in length was introduced through a 12F sheath in the common carotid artery. An on-table completion angiogram of the right-sided extracranial carotid arteries and the intracranial internal carotid artery and branches was obtained.

RESULTS

The completion angiogram and postoperative CT scan confirmed exclusion of the aneurysm sac from the circulation. The patient awoke from anesthesia with complete paralysis of the left arm. Recovery of movement commenced 1 hour later. A brain CT scan demonstrated the event to be an embolic stroke. Strength had returned by 7 days. Function of the arm was good 1 month after operation, but coordination for fine movements was lacking. At the 6-month follow-up, good arm function was maintained. A duplex ultrasound scan demonstrated not only continued exclusion of the aneurysm sac but occlusion of the endograft, also.

CONCLUSIONS

Endoluminal repair of aneurysms of the internal carotid artery is feasible but carries the risk of major morbidity as a result of peripheral embolization and early occlusion of the endograft.

The NK2.1 receptor is encoded by Ly-49C and its expression is regulated by MHC class I alleles

A dual receptor system composed of activation and inhibitory receptors apparently controls NK cell-mediated lysis. In the C57BL/6 mouse, the NK1.1 molecule acts as an activation receptor whereas Ly-49A, C and G2 can inhibit NK cell lysis of target cells expressing specific MHC class I molecules. We previously reported that NK2.1 is an activation receptor sharing structural properties with members of the NKR-P1 and Ly-49 receptor families. In this study, we have shown that NK2.1 is encoded by the previously described Ly-49C gene. We also found that the expression level of NK2.1/Ly-49C is modulated by H-2-dependent factors and that this regulation differs from that previously described for Ly-49A. Flow cytometry analyses of NK-enriched spleen cells from MHC congenic strains on C57BL/10 and BALB/c backgrounds indeed revealed that the level of NK2.1/Ly-49C expression, but not the number of positive cells, is low in strains expressing H-2b and H-2k haplotypes as compared to H-2d mice. Similar analyses of splenic NK cells from two series of congenic and congenic recombinant strains on the C57BL/10 background indicate that the main regulatory element(s) are most likely the H-2Kb and H-2Dk alleles. Together with our and others previous observations, these results identify the NK2.1/Ly-49C antigen as a receptor for MHC class I molecules whose expression is regulated by host MHC genes.

A prototype simulator for endovascular repair of abdominal aortic aneurysms

A prototype simulator for training in endovascular repair of abdominal aortic aneurysms (AAA) has been developed. Employing transparent models of human AAA complete with renal, iliac and femoral arteries, this system allows accurate simulation of aortography, road-mapping, catheter guidewire manipulation and stent-graft deployment while obviating the need for ionising radiation.

The Ly-49 family: genes, proteins and recognition of class I MHC

The Ly-49 family consists of at least nine members, of which Ly-49A and C have been found to be NK-cell inhibitory receptors specific for class I MHC. The functions of other Ly-49 molecules are still unclear. Further analysis of Ly-49 is complicated by the cross-reactivities of some anti-Ly-49 antibodies initially thought to be specific for individual Ly-49 molecules. Studies on the role of Ly-49 in hybrid resistance as well as on allelic exclusion are also complicated by our recent finding that a novel Ly-49CB6 gene is the likely allelic form of Ly-49CBALB as opposed to a previously reported highly related but distinct gene in B6 mice. In cell-cell binding assays, only Ly-49A and C show significant binding to class I MHC. Ly-49A and C also bind some polysaccharides, and carbohydrates on class I MHC seem to be important for its binding to Ly-49. However, this interaction involves not only the carbohydrate recognition domain of Ly-49 but also a part of the stalk region, suggesting that both carbohydrates and peptide backbone of class I MHC may be recognized by Ly-49. It is likely that additional Ly-49 molecules yet to be identified function as NK-inhibitory receptors specific for class I MHC.

Phase I trial of fluorouracil modulation by N-phosphonacetyl-L-aspartate and 6-methylmercaptopurine ribonucleoside (MMPR), and leucovorin in patients with advanced cancer

The results of several clinical trials support the hypothesis that biochemical modulation may enhance the antitumor activity of 5-Fluorouracil (5-FU). We have performed a phase I trial using a combination of three different biochemical modulators at the optimal dose established in previous clinical trials. The modulators include: phosphonacetyl-l-aspartate (PALA), which may increase 5-FU incorporation into RNA; leucovorin, which potentiates thymidylate synthase inhibition; and 6-methylmercaptopurine riboside (MMPR), which promotes the intracellular retention of fluorinated nucleotides. The treatment regimen consisted of PALA 250 mg/m2 day 1, followed 24 h later by MMPR 150 mg/m2 as an iv bolus, and the initiation of a 24-hour infusion of 5-FU along with leucovorin 50 mg/m2. This regimen was repeated weekly. Doses of 5-FU were escalated in cohorts of four or more patients from 2,000 to 2,600 mg/m2. Among 20 patients entered, the majority had colorectal cancer, and most had received prior 5-FU treatment. Toxicity was predominantly gastrointestinal, and diarrhea was dose-limiting at a 5-FU dose of 2600 mg/m2. There were three partial remissions observed, two of whom had colorectal cancer. Emerging data that casts doubt on the modulation value of PALA at this dose and schedule suggests that revision of this regimen be considered before Phase II trial.

Heterogeneity among Ly-49C natural killer (NK) cells: characterization of highly related receptors with differing functions and expression patterns

Ly-49C is a member of the polymorphic family of murine NK cell inhibitory receptors. The 5E6 antibody that defines a subset of NK cells responsible for the rejection of parental H-2d bone marrow by F1 mice has been shown previously to react with Ly-49C. Here, the 5E6 antibody was found to detect two Ly-49C-related molecules in B6 mice. Two cDNA clones were isolated from B6 NK cells, one identical to previously reported Ly-49CB6 and the other a novel cDNA. The deduced amino acid sequence of the latter differs from that of Ly-49CBALB at only 4 residues, whereas the previously reported Ly-49CB6 differs at 22 residues. Flow cytometric analyses of COS cells transfected with the two cDNAs showed that the 5E6 antibody binds to both Ly-49 molecules, while another anti-Ly-49C antibody, 4LO3311, binds to the newly described Ly-49C but not the previously reported Ly-49CB6. Two-color flow cytometric analysis detected 5E6+4LO3311- as well as 5E6+4LO3311+ subsets of NK cells from B6, but not BALB/c, mice. The level of Ly-49C expression on B6 NK cells detected by the 4LO3311 antibody was substantially lower than that on BALB/c NK cells. Binding specificity of the novel Ly-49CB6 was indistinguishable from that of Ly-49CBALB, whereas no binding was detectable with previously reported Ly-49CB6. These results demonstrate that the newly described Ly-49CB6, not the previously reported Ly-49CB6, is the probable B6 allelic form of Ly-49C. The previously reported Ly-49CB6 must be encoded by a separate gene and should be renamed Ly-49I. The implication of these results with respect to the role of Ly-49C in hybrid resistance is discussed.

Role of computed quantitation of immunohistochemical staining of Ki-67 antigen in diagnosing ampullary lesions

OBJECTIVE

To determine the possible role of Ki-67 antigen expression by visual and computed quantitation in diagnosing ampullary lesions.

STUDY DESIGN

Twenty-two cases of ampullary lesions treated at Thomas Jefferson University Hospital between 1989 and 1994 were analyzed. Four cases of adenoma, 4 of epithelial dysplasia in adenoma, 7 of well-differentiated adenocarcinoma and 7 of high grade adenocarcinoma were included. For each case three consecutive sections were obtained from the paraffin-embedded blocks. The first slide was stained with hematoxylin & eosin for visual diagnosis; the other two were immunoprocessed to evaluate the expression of Ki-67 antigen. Visual quantitation of Ki-67 was evaluated by light microscopy, and computed quantitation was performed utilizing the SAMBA 4000 cell image analysis system.

RESULTS

Immunohistochemical analysis of the ampullary lesions showed a positive correlation of Ki-67 expression, both by visual and computed quantitation, with biologic grade. The cell proliferation sequence was carcinoma, adenoma with dysplasia and adenomia.

CONCLUSION

Ki-67 antigen expression correlated highly with the progression of malignancy in ampullary lesions. Computed quantitation of Ki-67 was more sensitive than visual quantitation, especially in differentiating between low and high grade adenocarcinomas.

Modulation of gene expression in subjects at risk for colorectal cancer by the chemopreventive dithiolethione oltipraz

Prolonged exposure to mutagenic substances is strongly associated with an individual's risk of developing colorectal cancer. Clinical investigation of oltipraz as a chemopreventive agent is supported by its induction of the expression of detoxication enzymes in various tissues, and its protective activity against the formation of chemically induced colorectal tumors in animals. The goals of the present study were: to determine if oltipraz could induce detoxicating gene expression in human tissues; to identify effective non-toxic doses for more extensive clinical testing; and to establish a relationship between effects in the colon mucosa and those in a more readily available tissue, the peripheral mononuclear cell. 24 evaluable patients at high risk for colorectal cancer were treated in a dose-finding study with oltipraz 125, 250, 500, or 1,000 mg/m2 as a single oral dose. Biochemical analysis of sequential blood samples and colon mucosal biopsies revealed increases in glutathione transferase activity at the lower dose levels. These effects were not observed at the higher doses. More pronounced changes were observed in detoxicating enzyme gene expression in both tissues at all doses. Peripheral mononuclear cell and colon mRNA content for gamma-glutamylcysteine synthetase (gamma-GCS) and DT-diaphorase increased after dosing to reach a peak on day 2-4 after treatment, and declined to baseline in the subsequent 7-10 d. The extent of induction of gene expression in colon mucosa reached a peak of 5.75-fold for gamma-GCS, and a peak of 4.14-fold for DT-diaphorase at 250 mg/m2 ; higher doses were not more effective. Levels of gamma-GCS and DT-diaphorase correlated closely (P < or = 0.001) between peripheral mononuclear cells and colon mucosa both at baseline and at peak. These findings demonstrate that the administration of minimally toxic agents at low doses may modulate the expression of detoxicating genes in the tissues of individuals at high risk for cancer. Furthermore, peripheral mononuclear cells may be used as a noninvasive surrogate endpoint biomarker for the transcriptional response of normal colon mucosa to drug administration.

Recognition of class I major histocompatibility complex molecules by Ly-49: specificities and domain interactions

Ly-49 is a family type II transmembrane proteins encoded by a gene cluster on murine chromosome 6. One member of this family, Ly-49A, is expressed by a natural killer (NK) cell subset, binds to class I major histocompatibility complex (MHC) molecules, and blocks the killing of target cells bearing the appropriate H-2 antigens. Here we show that another member of this family which is expressed by an NK cell subset, Ly-49C, recognizes H-2b and H-2d structures which are distinct from and overlapping with those recognized by Ly-49A. Interactions between Ly-49A and C and their class I ligands are entirely blocked by the antibodies 5E6, YE1/48, YE1/32, and A1, all of which were found to recognize epitopes contained within the carbohydrate recognition domain (CRD). However, cell-cell binding assays revealed that class I binding specificity is conferred by a combination of sequences within both the CRD and a 19-amino acid adjacent region. We also investigated the question of whether Ly-49A and C form dimers on cells which express both receptors. When coexpressed on COS cells, sequential immunoprecipitation demonstrated that these receptors pair exclusively as homodimers, with no evidence for heterodimeric structures. These observations provide insight into both the biochemical nature of the Ly-49 family as well as the receptor functions of Ly-49C on NK cells.

Phase I trial of buthionine sulfoximine in combination with melphalan in patients with cancer

PURPOSE AND METHODS

Resistance to alkylating agents and platinum compounds is associated with elevated levels of glutathione (GSH). Depletion of GSH by buthionine sulfoximine (BSO) restores the sensitivity of resistant tumors to melphalan in vitro and in vivo. In a phase I trial, each patient received two cycles as follows: BSO alone intravenously (i.v.) every 12 hours for six doses, and 1 week later the same BSO as cycle one with melphalan (L-PAM) 15 mg/m2 i.v. 1 hour after the fifth dose. BSO doses were escalated from 1.5 to 17 g/m2 in 41 patients.

RESULTS

The only toxicity attributable to BSO was grade I or II nausea/vomiting in 50% of patients. Dose-related neutropenia required an L-PAM dose reduction to 10 mg/m2 at BSO 7.5 g/m2. We measured GSH in peripheral mononuclear cells (PMN), and in tumor biopsies when available, at intervals following BSO dosing. In PMNs, GSH content decreased over 36 to 72 hours to reach a nadir on day 3; at the highest dose, recovery was delayed beyond day 7. The mean PMN GSH nadirs were approximately 10% of control at BSO doses > or = 7.5 g/m2; at 13 and 17 g/m2, all but two patients had nadir values in this range. GSH was depleted in sequential tumor biopsies to a variable extent, but with a similar time course. At BSO doses > or = 13 g/m2, tumor GSH was < or = 20% of starting values on day 3 in five of seven patients; recovery had not occurred by day 5. We measured plasma concentrations of R- and S-BSO by high-performance liquid chromatography (HPLC) in 22 patients throughout the dosing period. Total-body clearance (CLt) and volume of distribution at steady-state (Vss) for both isomers were dose-independent. The CLt of S-BSO was significantly less than that of R-BSO at all doses, but no significant differences in Vss were observed between the racemates. Harmonic mean half-lives were 1.39 hours and 1.89 hours for R-BSO and S-BSO, respectively.

CONCLUSION

A biochemically appropriate dose of BSO for use on this schedule is 13 g/m2, which will be used in phase II trials to be conducted in ovarian cancer and melanoma.

Using and archiving the labor curves

Optimal interpretation of the events of labor requires integration of information about cervical changes, fetal descent, uterine contractions, fetal position and attitude, as well as fetal heart rate monitoring and maternal condition. The use and understanding of labor curves is a vital part of this process. The complexity and diversity of labor data lend itself to computer storage and analysis.

Absorption and presystemic metabolism of nefazodone administered at different regions in the gastrointestinal tract of humans

PURPOSE

The absorption and disposition of nefazodone (NEF) and its metabolites hydroxynefazodone (HO-NEF), m-chlorophenylpiperazine (mCPP) and triazole dione (dione) were assessed in 10 healthy subjects following infusion of NEF solution into the proximal and distal regions of the intestine vs administration of NEF solution orally by mouth.

METHODS

NEF HCl (400 mg) was infused over 5 hours into the proximal or distal intestine through a nasogastric tube, or orally ingested in 10 divided doses over 4.5 hours. The three treatments in the three-period crossover design were separated by one week.

RESULTS

The bioavailability of NEF, based on AUC(INF), from proximal and distal regions relative to that from oral administration was 97% and 106%, respectively. NEF was absorbed equally well from all three treatments with median Tmax of 5.0 hours which coincided with the duration of infusion. Mean Cmax of NEF was not different between proximal and oral administrations, however, mean Cmax after distal instillation was 40% lower than that after oral administration. Exposure to HO-NEF, mCPP and dione, following proximal instillation was also comparable to that after oral administration. AUC(INF) of HO-NEF and dione was significantly lower after distal instillation compared to that after oral administration but AUC(INF) of mCPP was not. Cmax of all metabolites was significantly lower after distal administration in comparison to oral treatment. Terminal half-life for NEF, HO-NEF and mCPP after distal administration was longer than the other two treatments.

CONCLUSIONS

NEF is absorbed throughout the length of the gastro-intestinal tract which supports the development of an extended-release formulation of NEF. The exposure to the metabolites (relative to NEF) was lower from the distal intestinal site compared to the proximal and oral site which may be explained by a reduced first pass of NEF by the cytochrome P450 3A4 in the distal intestine.

Time-dependent pharmacodynamic models in cancer chemotherapy: population pharmacodynamic model for glutathione depletion following modulation by buthionine sulfoximine (BSO) in a Phase I trial of melphalan and BSO

The development of time-dependent pharmacodynamic models in cancer chemotherapy has been extremely limited. A population approach was used to develop such a model to describe the effect of buthionine sulfoximine (BSO), via its active S-isomer (S-BSO), on glutathione (GSH) depletion in peripheral mononuclear cells. The Phase I trial utilized escalating doses of BSO, from 5 to 17 gm/m2, as a multiple infusion regimen. The population model consisted of a linear 2-compartment pharmacokinetic model coupled to an indirect response model. The indirect response model consisted of a GSH compartment with input and output rate processes that are modulated as a function of S-BSO and GSH concentrations. The model predicted the observed gradual depletion of GSH, a nadir at approximately 30 h after the last dose of BSO, and a return to baseline GSH levels. On the basis of an IC50 estimate of about 1.6 microM for inhibition of gamma-glutamylcysteine synthetase, the target enzyme of BSO, the population model predicted near identical GSH concentration time profiles over the dose range studied. Time-dependent pharmacodynamic models are seen as a powerful means to design dosing regimens and to provide a mathematical platform for mechanistic based models.

Cloning and developmental expression of Nsk2, a novel receptor tyrosine kinase implicated in skeletal myogenesis

The protein superfamily of transmembrane receptor tyrosine kinases (RTKs) are essential components of intercellular signalling pathways necessary for normal cellular regulation. We report the cloning and developmental expression pattern of Nsk2, a novel, structurally distinct mammalian RTK characterised by a putative extracellular region bearing four immunoglobulin-like domains. The Nsk2 locus was mapped to the distal region of mouse chromosome 13 and was found to be expressed preferentially in skeletal muscle amongst adult mouse tissues. Moreover, increased steady-state levels of Nsk2 transcripts were apparent on terminal differentiation of committed skeletal myoblast cell lines in vitro and multiple isoforms of the Nsk2 RTK were identified in skeletal myotube cultures. RNA in situ hybridisation studies of mouse embryos confirmed skeletal myogenesis to be a major site of Nsk2 expression during normal embryogenesis, and identified other likely sites of Nsk2 function in ganglia of the developing peripheral nervous system and various embryonic epithelia, including those of kidney, lung and gut, during fetal development. Taken together, our data suggest normal functions for Nsk2 RTKs in distinctive aspects of skeletal muscle development, neurogenesis and mesenchymal-epithelial interactions during organ formation.

Carbohydrate recognition by a natural killer cell receptor, Ly-49C

Ly-49 represents a family of type II transmembrane proteins containing C-type lectin domains. At least two members of the Ly-49 family, namely Ly-49A and Ly-49C, are expressed by distinct subsets of natural killer cells and bind to class I major histocompatibility complex antigens on the surface of target cells. In this report we have established that Ly-49C mediates carbohydrate recognition. The sulfated glycans fucoidan, lambda-carrageenan, and dextran sulfate were found to be potent inhibitors of Ly-49C-mediated cell adhesion, whereas other polysaccharides of similar size, charge, or sulfate content were noninhibitory. All of the polysaccharides which inhibited Ly-49C adhesion also blocked the binding of the antibody 5E6 to Ly-49C-expressing COS cells, confirming the direct protein-carbohydrate interaction. The enzymatic removal of specific carbohydrates from the target cell surface has shown that Ly-49C-mediated adhesion is not sialic acid-dependent, but is significantly decreased following fucosidase treatment. These results suggest an important role for carbohydrate recognition by natural killer cell receptors.

Risk-adjusted analysis of surgeon performance: a 1-year study

A 1-year prospective analysis was undertaken of all non-day-case general surgery in a district general hospital. Using the Physiological and Operative Severity Score for the enUmeration of Mortality and Morbidity (POSSUM) scoring system 3004 patients were assessed. From the predictions of mortality and morbidity so obtained, a quality measure, the ratio of observed to expected numbers of deaths and complications (O:E ratio) was determined for each surgeon, both overall and within specialty zones. The present study demonstrates the serious hazard in using 'raw' uncorrected mortality and morbidity statistics to compare surgeon performance. Mortality rates varied from 1.0 to 4.9 per cent whereas O:E ratios ranged from 0.83 to 1.06; morbidity rates varied from 5.3 to 12.6 per cent with O:E ratios 0.86-1.02. Great misunderstanding may result from the publication of surgeon or hospital 'league tables'. The present study demonstrates a technique that might allow surgeon performance to be monitored adequately and accurately.

Squamous cell carcinoma of the head and neck in the elderly

OBJECTIVE

While squamous cell carcinoma of the head and neck (HNSCC) most commonly affects individuals in the fifth to seventh decades of life, it occasionally arises in older patients. Biologic and epidemiologic factors of HNSCC in elderly patients have been investigated to shed light on the process of neoplastic transformation in that population.

DESIGN

The medical records of patients with new onset of HNSCC presenting between 1988 and 1993 were reviewed retrospectively.

SETTING

Tertiary-care hospital-based clinic.

PATIENTS

Eighty-one individuals who developed HNSCC of the upper aerodigestive tract after their 75th birthday constituted the study group. A control group consisting of 102 patients who developed HNSCC between the ages of 40 and 70 years was also analyzed.

MAIN OUTCOME MEASURE

Information about each individual's tobacco and ethanol exposure, family history of cancer, history of second primary cancer, treatment provided, and current disease status were derived from the medical record. The presence or absence of p53 gene mutation was tabulated for a subset of individuals in both the elderly and the middle-aged groups.

RESULTS

The elderly patients had a significantly lower degree of alcohol and tobacco exposure, but a significantly higher rate of second primary cancers, especially in sites outside the upper aerodigestive tract. There was no difference in the incidence of cancer in first-degree relatives in the two groups. These findings were interpreted in light of results from our laboratory examining the incidence of p53 gene mutation in a large number of patients with HNSCC. A significantly higher percentage of tumors from the younger group contained a p53 gene mutation. Major surgery was an integral part of the treatment plan for most of the older patient group despite their advanced age.

CONCLUSIONS

These findings suggest that HNSCC arising after the seventh decade of life less frequently involves a genetic change commonly found in younger patients. Heavy carcinogen exposure and p53 gene mutations are present less often in elderly individuals, whereas this group appears to be more susceptible to multiple cancers. The precise biologic factors involved in neoplastic transformation in this older population await discovery. Since aggressive therapy can be successfully tolerated by many elderly patients, an individualized approach to treatment is advocated.

Phase I trial of fluorouracil modulation by N-phosphonacetyl-L-aspartate and 6-methylmercaptopurine ribonucleoside

Inhibition of pyrimidine and purine synthesis has been demonstrated to potentiate 5-fluorouracil (5-FU) activity in preclinical models. Low-dose phosphonacetyl-L-aspartate (PALA) potentiates the incorporation of 5-FU into RNA, without detectably increasing its toxicity. 6-Methylmercaptopurine riboside (MMPR) results in inhibition of purine biosynthesis with elevation of phosphoribosyl pyrophosphate (PRPP), which in turn is believed to increase the phosphorylation and intracellular retention of 5-FU. We conducted a phase I clinical trial to determine the maximum tolerated dose of 5-FU in combination with low-dose PALA and a biochemically-optimized dose of MMPR. The regimen consisted of PALA 250 mg/m2 given on day 1, followed 24 h later by MMPR 150 mg/m2, and escalating doses of 5-FU from 1625 to 2600 mg/m2 by 24 h continuous infusion. This regimen was repeated weekly. A group of 29 patients with a diagnosis of malignant solid tumor were entered; their median performance status was 1. The dose-limiting toxicity was mucositis, while other gastrointestinal toxicity was minimal. Two patients also experienced ischemic chest pain during the 5-FU infusion. The maximum tolerated dose of 5-FU in this combination was 2600 mg/m2. Several responses were observed including a complete remission in a previously treated breast cancer patient and two partial responses in breast and colon cancer. MMPR pharmacokinetics were obtained from urine analyses in 21 patients on this trial; there was no correlation between the pharmacokinetics of MMPR and the toxicity observed. This regimen was well tolerated and phase II trials are warranted using PALA 250 mg/m2, MMPR 150 mg/m2, and 5-FU 2300 mg/m2 by continuous infusion over 24 h.

Phase I study of phosphonacetyl-L-aspartate, 5-fluorouracil, and leucovorin in patients with advanced cancer

Low-dose phosphonacetyl-L-aspartate (PALA) may potentiate both 5-fluorouracil (5-FU) incorporation into RNA and thymidylate synthase inhibition by 5-fluorodeoxyuridylate (5-FdUMP). The gastrointestinal toxicity of 5-FU is not increased by PALA administration. Exogenous leucovorin, on the other hand, which enhances thymidylate synthase inhibition, appears to increase the clinical toxicity of 5-FU in a dose-dependent manner. As a result, the clinical use of high-dose leucovorin requires a marked dose reduction of 5-FU. Extracellular leucovorin levels of 1 microM suffice to maximize the enhancement of thymidylate synthase inhibition in several models. We conducted a trial to add leucovorin to the PALA/5-FU regimen. We chose a leucovorin dose that was predicted to yield end-infusion total reduced folate concentrations of 1 microM. The major endpoint was to determine the maximum tolerated dose of 5-FU in this combination. The regimen consisted of 250 mg/m2 PALA given on day 1 and, 24 h later, escalating 5-FU doses ranging from 1,850 to 2,600 mg/m2 admixed with 50 mg/m2 leucovorin and given by 24-h infusion. Courses were repeated weekly. A total of 24 patients with a median performance status of 1 were entered at three dose levels. Diarrhea was dose-limiting; 6/13 patients had grade II or worse diarrhea at 2,600 mg/m2. Dose modification resulted in a mean dose intensity of 2,300 mg/m2 at both the 2,600- and 2,300-mg/m2 dose levels. The 2,300-mg/m2 dose is suitable for phase II testing of this regimen. Three patients (two with breast cancer and 1 with sarcoma) had a partial remission. We measured steady-state concentrations (Css) of 5-FU in 23 patients. The mean Css increased with dose from 0.738 to 1.03 micrograms/ml. Total body clearance did not vary with dose in this range. Patients with grade II or worse diarrhea had a higher mean Css (1.10 +/- 0.19) than those with grade O or I toxicity (0.835 +/- 0.25, P < 0.02). Total bioactive folates (bound and free) were measured using a biological assay. Pretreatment values ranged from 2 to 52 nM and were not predictive of toxicity. End-infusion (23-h) values were somewhat lower than predicted and ranged from 400 to 950 nM. The risk of diarrhea was positively correlated with end-infusion total folate values. In a logistic regression analysis, total folate values obtained at 23 h were a more powerful predictor of diarrhea than were 5-FU Css values.(ABSTRACT TRUNCATED AT 400 WORDS)

Expression of different members of the Ly-49 gene family defines distinct natural killer cell subsets and cell adhesion properties

The murine Ly-49 antigen belongs to a family of type II transmembrane molecules containing lectin-like domains. The original member of this family, Ly-49A, has been demonstrated to be expressed by a subpopulation of natural killer (NK) cells, bind certain class I major histocompatibility complexes (MHC), and act as a negative regulator of lytic activity. The expression patterns and functional activities of the other Ly-49s, however, is unknown. We extended the study of this family by isolating cDNAs encoding two new Ly-49 molecules. The reactivity of these and previously identified Ly-49 molecules with NK antibodies was tested in a COS cell expression system. YE1/32 and YE1/48 bound Ly-49A specifically, and 5E6 reacted only with Ly-49C. Three-color flow cytometric analysis demonstrated Ly-49A and Ly-49C expression defines complex, but distinct subsets within NK1.1+ cells. Some NK1.1-CD3+ as well as NK1.1-CD3- cells expressing Ly-49A or C were also detected. Analysis of MHC congenic strains of mice demonstrated that YE1/32+ and YE1/48+ NK cells are not deleted, as has been shown with the Ly-49A mAb A1. Furthermore, COS cells transfected with Ly-49A bound H-2d and H-2k cell lines, whereas Ly-49C transfectants bound H-2d, H-2k, H-2b, and H-2s. The antibodies 5E6 and 34-1-2S (anti-class I MHC) inhibited the binding of Ly-49C to an H-2s cell line. These results imply that the NK cell antigens Ly-49A and C bind to different repertoires of class I MHC molecules.

The value of urinalysis in differentiating acute pyelonephritis from lower urinary tract infection in febrile infants

There is an ongoing debate on the best way to screen febrile infants for urinary tract infection. We examined the urinanalysis (UA) findings on admission among infants less than 16 weeks old, with and without acute pyelonephritis (APN), as defined by the dimercaptosuccinic acid (DMSA) renal scan findings, performed during a 57-month period. Forty-nine cases with a positive DMSA scan were compared with 79 negative study cases. A negative UA for leukocytes (< 5 white blood cells/high power field) was found in 4 of 49 (8.1%) cases with APN by DMSA, and in 34 of 79 (43%) cases with a negative DMSA (odds ratio 10.88 (95% confidence interval, 2.31 to 70.3; P < 0.001)). Three of the 4 infants not suspected to have APN by their UA findings would have been admitted for a full sepsis workup based on their clinical presentation and/or their laboratory findings on admission. We conclude that a fresh UA may be a sufficient screening method for the exclusion of APN in infants assessed for fever of no obvious origin.

Mutations in the conserved regions of p53 are infrequent in betel-associated oral cancers from Papua New Guinea

Seventy-five % of the world's oral cancers arise in developing countries. In high incidence areas of Southeast Asia such as Papua New Guinea (PNG) the major region-specific risk exposure is betel quid chewing. While it has been shown that p53 gene mutations in the conserved midregion (exons 5-9) are a common feature of oral cancers in the developed world, there is no information on this type of genetic lesion in betel quid-associated oral cancers. We examined 50 oral squamous cell carcinomas, 20 from Baltimore, MD and 30 from PNG, for mutations in exons 5-9 of the p53 gene. DNA extracted from frozen biopsies was amplified by polymerase chain reaction, the purified product was sequenced directly, and mutations were confirmed by repeating the entire procedure. Mutations were found in 3 of 30 tumors from PNG (10%), whereas 9 mutations were detected among the 20 tumors (45%) from Baltimore, MD. This difference in frequency is statistically significant (P < 0.01) by chi 2 analysis. Nuclear accumulation of p53 protein, determined by immunohistochemistry with the CM-1 antiserum, was observed in the PNG cases harboring a missense mutation of the p53 gene. In agreement with the low number of PNG cancers with mutations, only 17% of the cases from PNG were immunostain positive. To explore whether less conserved regions of the gene are preferential targets for alterations in this patient group, sequence analysis in tumors from PNG was extended to outlying regions of the gene (all of exons 4 and 10, and splice sites), but mutations in only two additional tumors were identified. The presence of human papillomavirus DNA in PNG cases was examined with a polymerase chain reaction-based procedure, and viral sequences (human papillomavirus strains 11/16) were detected in two tumors. Human papillomavirus-triggered degradation of the tumor suppressor protein is thus unlikely to be a typical pathway to p53 dysfunction in tumors from PNG.

The Eck receptor tyrosine kinase is implicated in pattern formation during gastrulation, hindbrain segmentation and limb development

Members of the protein superfamily of transmembrane receptor tyrosine kinases are key components of intercellular signal transduction pathways that elicit appropriate cellular responses to environmental cues during development of multicellular organisms. In a search for additional receptor tyrosine kinases expressed during mouse embryogenesis we cloned the murine homolog of Eck, a member of the Eph subfamily, that maps to the distal region of mouse chromosome 4. Specific antisera defined Eck in murine embryonic cells as a glycoprotein of 130 kDa with an intrinsic autophosphorylation activity. Immunohistochemical staining and laser scanning microscopy revealed a dynamic and tightly regulated distribution of Eck receptor protein in the developing mouse embryo. During gastrulation, a high transient distribution of Eck was seen in mesodermal cells aggregating in the midline as notochordal plate. A similar restriction of Eck receptor protein was apparent along the rostrocaudal axis of the developing neural tube. In hindbrain neuroepithelia, Eck protein localised specifically to cells of rhombomere 4 and was also seen transiently in cells populating second and third branchial arches and neurogenic facial crest VII-VIII and IX-X. Receptor distribution also implicated Eck in development of the proximodistal axis of the limb, expression being restricted to distal regions of limb bud mesenchyme. At later stages, additional sites of Eck protein expression were seen in the cartilaginous model of the skeleton, tooth primordia, infundibular component of the pituitary and various fetal tissue epithelia. Taken together, our data suggest pleiotropic functions for the Eck receptor, initially in distinctive aspects of pattern formation and subsequently in development of several fetal tissues, and reveal possible allelism with known mouse developmental mutant loci.

The interleukin (IL) 2 receptor beta chain is shared by IL-2 and a cytokine, provisionally designated IL-T, that stimulates T-cell proliferation and the induction of lymphokine-activated killer cells

Late-phase human T-cell lymphotropic virus I-associated adult T-cell leukemia cells express IL-2 receptors (IL-2R) but no longer produce IL-2. We have reported that the IL-2-independent adult T-cell leukemia line HuT-102 secretes a cytokine, provisionally designated IL-T, that stimulates T-cell proliferation and lymphokine-activated killer cell activity. Stimulation of proliferation of the cytokine-dependent human T-cell line Kit-225 mediated by HuT-102-conditioned medium or by 3200-fold-purified IL-T was not blocked by the addition of antibodies against IL-2 or IL-2R alpha subunit. However, IL-T-mediated stimulation of this human T-cell line was inhibited by addition of Mik-beta 1, an antibody that binds specifically to IL-2R beta subunit. In addition, the activation of large granular lymphocytes to lymphokine-activated killer cells mediated by IL-T-containing conditioned medium was not blocked by antibodies directed toward IL-2 or IL-2 alpha but was inhibited by an antibody to IL-2R beta, suggesting the requirement of this receptor subunit for IL-T action. This conclusion was confirmed using an IL-3-dependent murine myeloid precursor cell line, 32D, that expresses IL-2R alpha and IL-2R gamma, but not IL-2R beta. Neither IL-2 nor IL-T stimulated 32D cell proliferation. However, after transfection with the gene encoding human IL-2R beta, 32D beta cells proliferated on addition of either cytokine. The IL-T-mediated stimulation of 32D beta proliferation was inhibited by an anti-IL-2R beta antibody but not by an anti-IL-2 antibody. Thus, the IL-T-mediated stimulation of T-cell and lymphokine-activated killer cell activation requires the expression of the IL-2R beta subunit.

A lymphokine, provisionally designated interleukin T and produced by a human adult T-cell leukemia line, stimulates T-cell proliferation and the induction of lymphokine-activated killer cells

In early phases of human T-cell lymphotrophic virus I-induced adult T-cell leukemia (ATL), the malignant cell proliferation is associated with an autocrine process involving coordinate expression of interleukin (IL) 2 and its receptor. However, during late-phase ATL, leukemic cells no longer produce IL-2 yet continue to express high-affinity IL-2 receptors. During studies to define pathogenic mechanisms that underlie this IL-2-independent proliferation, we demonstrated that the ATL cell line HuT-102 secretes a lymphokine, provisionally designated IL-T, that stimulates T-cell proliferation and the induction of lymphokine-activated killer cells. Conditioned medium from HuT-102, when added to the IL-2-dependent CTLL-2 line, yielded a stimulation index of 230. Since CTLL-2 was purported to be IL-2-specific, we performed a number of studies to exclude IL-2 production by HuT-102. Stimulation of CTLL-2 cells by HuT-102-conditioned medium was not meaningfully inhibited by addition of an antiserum to IL-2. Furthermore, uninduced HuT-102 cells did not express mRNA encoding IL-2 as assessed by Northern blot analysis. No biological activity on CTLL-2 cells was mediated by purified IL-1, IL-3, IL-4, IL-5, IL-6, IL-7, IL-9, IL-10, IL-12, IL-13, or granulocyte/macrophage colony-stimulating factor, thus differentiating these factors from IL-T. Based on preliminary biochemical data, IL-T is a protein with a pI value of 4.5 and a molecular mass in SDS gels of 14 kDa. In addition to its action on CTLL-2 cells, 3200-fold-purified IL-T stimulated proliferation of the human cytokine-dependent T-cell line Kit-225. Furthermore, addition of IL-T enhanced cytotoxic activity of large granular lymphocytes (i.e., induced lymphokine-activated killer cells). Thus, IL-T is a lymphokine that plays a role in T-cell proliferation and induction of lymphokine-activated killer cells. Furthermore, IL-T may contribute to IL-2-independent proliferation of select ATL cells and lines.

A vital component of care: the nurse's role in recognising altered body image

Using the example of people with spinal injuries, this article examines the impact of illness or injury on people's body image. Successful assessment and evaluation by nurses of altered body image--from physical, psychological and social angles--are vital components of patient care and support.

Predictors of coronary dissection following percutaneous transluminal coronary balloon angioplasty

To determine predictors of acute coronary dissection after coronary angioplasty, we studied 170 consecutive patients who underwent arterial dilatations of 234 arteries. Coronary dissection occurred in 103 (44%) arteries. More dissections occurred in women [40/73 (55%) versus 63/161 (39%), p < 0.03] and in patients with long lesions [45/74 (61%) versus 56/158 (35%), p < 0.0005]. Balloon/arterial diameter ratio was higher in patients with dissection (1.1 +/- 0.2 versus 1.0 +/- 0.2, p < 0.02). Complications did not differ in patients with and without dissection except for non-Q wave myocardial infarctions which were more frequent in patients with coronary dissection [10/12 (83%) versus 2/12 (17%), p < 0.01]. Thus coronary dissection during angioplasty is relatively frequent. However, most dissections are not associated with complications. Balloon dilatation of lesions in female patients and in patients with long lesions are more likely to result in dissection.

Clinical and angiographic determinants of initial percutaneous transluminal coronary angioplasty success

Clinical and anatomic determinants of primary success of percutaneous transluminal coronary angioplasty were retrospectively evaluated in 299 patients. Successful angioplasty (residual stenosis < 50%) was achieved in 350 (94%) of 373 lesions. The success rate in patients chronically treated with aspirin was higher than that of patients not treated with aspirin (95% versus 86%, P < 0.03). An additional finding was that the success rate in patients referred for coronary angioplasty because of acute myocardial infarction or postinfarction angina was lower than that of those without these characteristics (89% versus 96%, P < 0.01). No other clinical features studied influenced the outcome of coronary angioplasty. The angiographic characteristics of the lesions did not differ between patients with successful or failed angioplasty except for the degree of stenosis prior to the procedure, being lower in patients with successful procedure (92.4 +/- 7.6% versus 97.3 +/- 3.1%), P < 0.002). Thus coronary angioplasty can be performed with a high rate of success. Long-term pretreatment with aspirin may have a beneficial effect.

Atrial natriuretic factor and arginine vasopressin production in tumor cell lines from patients with lung cancer and their relationship to serum sodium

Patients with lung cancer (n = 263) were studied to determine the relationship among ectopic production of atrial natriuretic factors (ANF) and arginine vasopressin (AVP), serum sodium, and patient outcome. Of 133, 21 (16%) patients with small cell lung cancer (SCLC) had hyponatremia (serum sodium, < 130 mmol/liter), compared to none of 130 (0%) patients with non-small cell lung cancer (P < 0.0001). Patients with extensive-stage SCLC and hyponatremia had shorter survival than patients with extensive stage SCLC and normal serum sodium values (P = 0.012). Of the 11 hyponatremic patients with SCLC and tumor cell lines available for study, 9 produced ANF mRNA, 7 of 11 produced AVP mRNA, and 5 of 11 produced both ANF mRNA and AVP mRNA. All 11 cell lines produced either ANF mRNA and ANF peptide or AVP mRNA and AVP peptide, or both. The quantity of AVP peptide in the tumor cell lines was more closely associated with hyponatremia in the patients (P = 0.0026, r2 = 0.28) than was the production of ANF peptide (P = 0.066, r2 = 0.12), although neither association was strong. All tumor cell lines studied from SCLC patients with hyponatremia produce ANF and/or AVP mRNA and peptides.

Radioimmunoassay for ceronapril, a new angiotensin-converting enzyme inhibitor, and its application to a pharmacokinetic study in healthy male volunteers

Ceronapril is a member of a new chemical class of angiotensin-converting enzyme inhibitors being developed by The Bristol-Myers Squibb Pharmaceutical Research Institute. A radioimmunoassay (RIA) has been developed for the measurement of ceronapril in biological fluids. The RIA has a range of 0 to 500 ng/ml and has the sensitivity to detect 1.0 ng/ml of ceronapril. Satisfactory zero binding and sensitivity were obtained after a 2-h incubation at room temperature or overnight at 4 degrees C. Separation of the antibody-bound and free radiolabel was achieved by employing polyethylene glycol-goat anti-rabbit gamma-globulin separant. A quantitative recovery of the exogenous analyte was obtained at all concentrations of ceronapril tested. Intraassay coefficients of variance (CV's) were 3.9% and 4.6% for the low and medium controls, respectively. A highly significant statistical correlation between RIA and [14C]TLRC was observed for both plasma and urine samples. Clinical samples from the ascending dosage studies have been analyzed by the ceronapril RIA. The maximum concentration and the area under the plasma concentration-time curve did not increase in a dose-proportional manner for doses above 100 mg.

Gastrointestinal transit and systemic absorption of captopril from a pulsed-release formulation

Captopril has been administered to eight healthy male subjects by means of a pulsatile delivery system that was designed to release the drug in the colonic region of the intestine. The gastrointestinal transit and pulsatile release were followed using gamma scintigraphy. A pulsatile capsule system with release after a nominal 5-hr period was found to perform reproducibly in vitro and in vivo. In six of the eight subjects, the drug was delivered to the colon, and in the remaining two subjects, to the terminal ileum. Measurable blood levels of free captopril were found in three subjects. Variable instability of the drug in the distal intestine is suggested as a possible reason for the lack of absorption of the drug in the majority of subjects.

Percutaneous transluminal coronary angioplasty in unstable and stable angina pectoris: a comparison of immediate success and complications

To determine the success rate and the safety of percutaneous transluminal coronary angioplasty in patients with unstable angina pectoris (group 1) versus stable angina (group 2), we studied 299 consecutive patients who underwent coronary angioplasty of 373 consecutive lesions. Of these patients, 149 had unstable angina pectoris and dilation of 188 arteries. The success rate was high and similar in both groups (95 and 93%, respectively). The groups did not differ in regard to the lesion characteristics, vessels and number of sites dilated except for an increase in the presence of thrombus in the unstable angina group (p < 0.03). Although there was a higher incidence of coronary thrombus and more acute myocardial infarction in group 1, the major complication rate did not differ from that of group 2 and was low in both of them (3 and 2%, respectively). No deaths occurred. Six patients (3 in each group) needed urgent coronary artery bypass grafting while 3 additional patients developed acute Q-wave myocardial infarction (all of them in group 1). Thus, percutaneous transluminal coronary angioplasty is a safe and successful procedure in patients with unstable angina as well as in patients with stable angina pectoris.