Clinical relevance of in vitro propagation of activated lymphocytes from endomyocardial biopsy samples of pediatric heart transplant recipients

In vivo activated T-lymphocytes can be cultured from endomyocardial biopsy samples of human cardiac allografts, sometimes even in the absence of histological rejection. We investigated the clinical relevance of this "lymphocyte growth assay" in pediatric heart transplant recipients. Specifically, we wished to determine if: (i) positive lymphocyte growth from EMB samples in the absence of significant rejection identifies a patient as being at increased risk for the development of acute rejection; (ii) withdrawal or major dose reduction of corticosteroids in the presence of lymphocyte growth results in high risk of rebound rejection; and (iii) presence of lymphocyte growth during acute rejection helps predict the response to treatment. Cultures were performed on 789 consecutive EMB samples from 65 pediatric heart transplant recipients in media containing 30 U/ml of recombinant IL-2. T-lymphocytes were cultured from 16% of EMB samples with low grade rejection (grade 0-1b) and from 34% of EMB samples with grade 2-4 rejection. EMB samples obtained early post-transplant (<180 days) were significantly more likely to yield positive lymphocyte growth compared to biopsies obtained late for any given rejection grade. Lymphocyte growth was comparable between patients managed with cyclosporine or tacrolimus based immunosuppression. For 227 EMB samples without rejection, a subsequent EMB sample was obtained within 12 weeks. Lymphocyte cultures were positive in 47 of these 227 EMB samples (21%), and in 19 out of 47 (40%) cases acute rejection (grade 2-4) was present on the follow-up EMB sample. By contrast, of 180 biopsies without growth, only 29 (16%) showed rejection at the next EMB (p<0.0001). When a follow-up biopsy was performed within 12 weeks of corticosteroid withdrawal, "rebound rejection" was observed in 3 out of 10 (30%) cases where the previous EMB sample yielded positive lymphocyte growth and in 4 out of 38 (11%) cases when it did not (p=0.29). The presence of lymphocyte growth in association with rejection was also predictive of whether rejection would resolve following high dose intravenous corticosteroid therapy (persistent rejection in 33 out of 50 (66%) cases with positive growth, versus 25 out of 80 (31%) cases without growth (p<0.0001)). Thus, positive lymphocyte growth is strongly associated with higher grade of rejection and earlier time from transplantation. Lymphocyte growth in the absence of rejection indicates high risk for rejection within the next 12 weeks. Growth in association with acute rejection indicates high probability of persistence of rejection following treatment with high dose corticosteroids.

Laparoscopic resection of an intra-abdominal cystic mass: a cystic mesothelioma

The clinical features of a patient with an intra-abdominal cystic mass do not lead to a specific diagnosis. Aspiration is usually ineffective because the mass recurs and cytologic investigation is often non-diagnostic. Conservative management is unsuccessful because symptoms often persist. Surgical management of cystic masses is required for definitive management and pathologic diagnosis. A laparoscopic approach to the diagnosis and treatment can provide essential anatomic information and a complete resection with minimal morbidity. A laparoscopic technique using 3 trocars and maintaining the integrity of the mass allows complete excision and removal of large intra-abdominal cystic masses as reported in a 43-year-old patient with a large intra-abdominal cystic mass identified as a benign cystic mesothelioma.

Integration of surface modification and 3D fabrication techniques to prepare patterned poly(L-lactide) substrates allowing regionally selective cell adhesion

Regeneration of organizationally complex tissue requires regulation of spatial distributions of particular cell types in three dimensions. In this paper we demonstrate an integration of polymer processing and selective polymer surface modification using methods suitable for construction of three-dimensional polymer scaffolds which may aid such cell organization. Specifically, the surfaces of degradable polyesters were modified with poly(ethylene-oxide) (PEO)-poly(propylene-oxide) (PPO) copolymers using a process compatible with a solid free-form fabrication technique, the 3DP printing process. We demonstrate inhibition of cell (hepatocyte and fibroblast) adhesion to regions of two-dimensional poly(lactide) (PLA) substrates modified with PEO-PPO-PEO copolymers. We further show that PEO-PPO-PEO-modified surfaces which are not adhesive for hepatocytes or fibroblasts can be made selectively adhesive for hepatocytes by covalent linkage of a carbohydrate ligand specific for the hepatocyte asialoglycoprotein receptor to the PEO chain ends. Our approach may be generally useful for creating regionally selective, microarchitectured scaffolds fabricated from biodegradable polymers, for spatial organization of diverse cell types.

Lipomas of the head and neck in children

Head and neck lipomas in the pediatric population are rarely described in the literature. Two patients who presented to the Hospital for Sick Children with rapidly enlarging head and neck lipomas are presented. Radiographic imaging, including CT and MRI, as well as fine needle aspiration implicated a lipoma as the probable diagnosis. Both patients were treated by surgical excision. The clinical behavior, diagnostic work-up and treatment of these rare lesions are the focus of this study.

New generation dopaminergic agents. 1. Discovery of a novel scaffold which embraces the D2 agonist pharmacophore. Structure-activity relationships of a series of 2-(aminomethyl)chromans

A series of 2-(aminomethyl)chromans (2-AMCs) was synthesized and evaluated for their affinity and selectivity for both the high- and low-affinity agonist states (D2High and D2Low, respectively) of the dopamine (DA) D2 receptor. The 7-hydroxy-2-(aminomethyl)chroman moiety was observed to be the primary D2 agonist pharmacophore. The 2-methylchroman moiety was discovered to be an entirely novel scaffold which could be used to access the D2 agonist pharmacophore. Attaching various simple alkyl and arylalkyl side chains to the 7-hydroxy 2-AMC nucleus had significant effects on selectivity for the D2High receptor vs the 5HT1A and alpha 1 receptors. A novel DA partial agonist, (R)-(-)-2-(benzylamino)methyl)chroman-7-ol [R-(-)-35c], was identified as having the highest affinity and best selectivity for the D2High receptor vs the alpha 1 and 5HT1A receptors. Several regions of the 2-AMC nucleus were modified and recognized as potential sites to modulate the level of intrinsic activity. The global minimum conformer of the 7-hydroxy-2-AMC moiety was identified as fulfilling the McDermed model D2 agonist pharmacophoric criteria and was proposed as the D2 receptor-bound conformation. Structure-activity relationships gained from these studies have aided in the synthesis of D2 partial agonists of varying intrinsic activity levels. These agents should be of therapeutic value in treating disorders resulting from hypo- and hyperdopaminergic activity, without the side effects associated with complete D2 agonism or antagonism.

Influence of CO2 pneumoperitoneum on systemic and peritoneal cell-mediated immunity

Port site metastases could be due to mechanical reasons or impairment of host defenses. As it is known that carbon dioxide is toxic for lymphocytes in vitro we decided to investigate lymphocyte stress during laparoscopy. Blood samples and peritoneal fluids were obtained before and after pneumoperitoneum from 16 patients undergoing laparoscopic cholecystectomy. Lymphocyte subsets were determined by flow cytometry. Propidium iodide was used as a lymphocyte vitality test. Cytokines were measured by an ELISA system. Significant falls in the absolute lymphocyte count and T3 and T4 lymphocytes occurred on postoperative day 1 with a quick return to the preoperative value on day 2. T8, natural killer cells, T4/T8, and T4+/T8+ counts were stable. Interleukins 1 beta and 6 and tumor necrosis factor-alpha were depressed during the two postoperative days. Peritoneal lymphocytes were not destroyed by pneumoperitoneum as demonstrated by the propidium test, nor were they locally impaired by carbon dioxide. The circulating lymphocyte subpopulation decrease favors moderate, brief immunodepression. The origin of port site metastases is not immunologic depression but, rather, facilitated implantation of malignant cells by hyperpressure into raw tissues.

The lateral approach to laparoscopic splenectomy

BACKGROUND

Laparoscopic splenectomy has been shown to result in shorter hospital stays and a quicker return to work than conventional splenectomy. Having tried the anterior 5 trocar approach, we developed a 4 trocar lateral approach and now present our experience with 22 cases.

METHODS

All patients were placed in the right lateral decubitus position. A 10-mm trocar was inserted in the left subcostal region, 2 in the flank, and a 5-mm trocar dorsally. A 30 degrees laparoscope was used. Splenectomy was performed for varying pathologies.

RESULTS

Operating room (OR) time averaged 169 minutes, spleen weight 513 grams, and postoperative (post-op) stays 5.4 days (median 3 days). One patient was converted to laparotomy. There were no deaths, post-op abscesses, pancreatic injuries, or bleeding complications.

CONCLUSIONS

The lateral approach affords superior exposure, allowing easier dissection of splenic hilar structures. Over varying patient habitus and spleen size it has been demonstrated to be the approach of choice for laparoscopic splenectomy.

Heterotopic brain in the parapharyngeal space

There have been numerous reports of various types of heterotopic tissue in the head and neck. Heterotopic cartilage, gastric tissue, thyroid, and salivary gland in such various locations as tongue, gingiva, palate, nasopharynx, parapharyngeal space, and neck have been frequently reported. Heterotopic brain in the parapharyngeal space causing airway obstruction in the neonate has been rarely described. These benign masses are capable of expansion and because of their location, can lead to significant airway and feeding difficulties. We describe 3 cases of heterotopic brain tissue in the parapharyngeal space causing feeding difficulties and airway obstruction in the neonatal period. Two were initially misdiagnosed as lymphatic malformations. In the third, a nine month delay in diagnosis occurred. The diagnostic features of heterotopic brain in this location and some management suggestions in treating such a lesion are discussed.

Objective assessment of the response to treatment of severe heart failure using a 9-minute walk test on a patient-powered treadmill

BACKGROUND

No previous studies have demonstrated the changes in exercise capacity that occur during treatment of decompensated severe heart failure. The authors assessed the efficacy and safety of using a patient-powered treadmill to objectively measure exercise capacity and its relationships, if any, to symptom scores and body weight.

METHODS AND RESULTS

Changes in time-limited exercise capacity on a patient-powered treadmill were assessed during inpatient treatment of 12 patients with decompensated chronic heart failure (New York Heart Association classes III and IV). Patients performed a 9-minute walk test daily for 7 days and again at the 6-week follow-up examination. They also completed a 24-item symptom score questionnaire. After treatment, there was a rapid, significant increase in total distance walked, with the increase beginning as early as the second day after admission (mean distance walked +/- SEM, 54 +/- 27 m and 174 +/- 54 m on admission and on day 2, respectively, P < .05). Improvement was maintained throughout the period in the hospital and at 6 weeks (P < .001). Patients reported symptomatic improvement, but this did not reach significance until 4 days after admission (P < .05). Weight loss was not significant. Improved exercise capacity correlated with reduced symptoms and weight loss, but preceded these by several days.

CONCLUSIONS

In patients with decompensated chronic heart failure, this exercise test provides a safe, practical, inexpensive, and objective assessment of functional capacity, providing certain advantages over other indices of response to therapy, such as symptom scores and weight loss. Improvement of exercise capacity does not occur concurrently with relief of symptoms and weight loss.

In vitro cell response to differences in poly-L-lactide crystallinity

Many different processing techniques are currently being used to produce tissue regeneration devices from polyesters in the polylactide/polyglycolide family. While it is generally well recognized that processing techniques influence bulk mechanical and degradation properties of these materials, the effects on surface properties are relatively less well studied. We thus investigated the effects of processing conditions that are known to change bulk properties, but not composition, on the surface properties of poly-L-lactide (PLLA). Specifically, we investigated the role of bulk crystallinity of PLLA substrates on several physiochemical aspects of the surface and on the attachment, morphology, and differentiated function of cultured primary hepatocytes and growth of 3T3 fibroblasts. We fabricated smooth, clear PLLA films of 13-37% crystallinity. Glancing angle X-ray diffraction indicated that low crystallinity films lacked order in the first 50 A of the surface while relatively high crystallinity films had detectable order in this range. In other aspects, the surfaces of all PLLA substrates appeared identical with XPS, SEM, and advancing contact angle analysis, but contact angle hysteresis was slightly greater for more crystalline films. Although the physicochemical properties of the surfaces appeared almost identical, we observed differences in cell behavior on less crystalline versus more crystalline films. Hepatocytes formed spheroids on all PLLA substrates, but spheroid formation was faster (24-48 H) on crystalline substrates. quantitative image analysis was used to assess the average cell area as a function of time in culture, and our data confirm previous reports that retention of differentiated function is inversely related to cell spreading where function was assessed by P-450 enzyme activity. In addition, the growth rate of 3T3 fibroblasts was lower on crystalline substrates than on amorphous substrates. An important conclusion from this work is that processing techniques that lead to seemingly inconsequential changes in bulk and surface properties of these polymers may influence biological response.

Systematic mutational analysis of the death domain of the tumor necrosis factor receptor 1-associated protein TRADD

Tumor necrosis factor receptor 1 (TNF-R1) mediates most of the biological properties of TNF including activation of the transcription factor NF-kappaB and programmed cell death. An approximately 80-amino acid region within the intracellular domain of the receptor, termed the death domain, is required for signaling NF-kappaB activation and cytotoxicity. A TNF-R1-associated protein TRADD has been discovered that interacts with the death domain of the receptor. Elevated expression of TRADD in cells triggers both NF-kappaB activation and programmed cell death pathways. The biological activities of TRADD have been mapped to a 111-amino acid region within the carboxyl-terminal half of the protein. This region shows sequence similarity to the death domain of TNF-R1 and can self-associate and bind to the TNF-R1 death domain. We have performed an alanine scanning mutagenesis of TRADD's death domain to explore the relationship among its various functional properties. Mutations affecting the different activities of TRADD do not map to discrete regions but rather are spread over the entire death domain, suggesting that the death domain is a multifunctional unit. A mutant that separates cell killing from NF-kappaB activation by the TRADD death domain has been identified indicating that these two signaling pathways diverge with TRADD. Additionally, one of the TRADD mutants that fails to activate NF-kappaB was found to act as dominant negative mutant capable of preventing induction of NF-kappaB by TNFalpha. Such observations provide evidence that TRADD performs an obligate role in TNF-induced NF-kappaB activation.

Laparoscopic repair of large incisional hernias

Conventional repair of large incisional hernias is often associated with a painful postoperative recovery and a delayed return to normal activities. We describe here a technique of laparoscopic incisional hernia repair and review our experience with 30 cases. Hernias ranging in size from 10 to 420 cm2 (mean, 104 cm2) were repaired using a polytetrafluoroethylene patch (16 cases) and a Prolene mesh (14 cases). Operating room time ranged from 45 mins to 190 min (mean 108 mins). Postop stay ranged from 1 to 17 days (mean, 4.3 days; median, 3 days). Follow-up extends beyond 18 months. Postoperative complications included ileus (three cases) trocar site infection (one case) and urinary retention (two cases). There has been one hernia recurrence to date. Our experience with the laparoscopic repair of incisional hernias reveals it to be technically feasible with minimal morbidity, allowing patients prompt resumption of regular activities. Prospective comparison with conventional repair and longer follow-up are needed.

Sp1 is a component of the cytokine-inducible enhancer in the promoter of vascular cell adhesion molecule-1

Transcription of the vascular cell adhesion molecule-1 (VCAM-1) gene in endothelial cells is induced by the inflammatory cytokines interleukin-1 beta, tumor necrosis factor-alpha, and lipopolysaccharide. Previous studies demonstrated that the cytokine-response region in the VCAM1 promoter contains binding sites for the transcription factors nuclear factor-kappa B (NF-kappa B) and interferon regulatory factor-1. Using a saturation mutagenesis approach, we report that the cytokine-inducible enhancer consists of these previously characterized elements and a novel region located 3' of the NF-kappa B sites. Electrophoretic mobility shift assays and DNase I footprint studies with endothelial nuclear extracts and recombinant protein revealed that the transcriptional activator Sp1 interacts with this novel element in a specific manner. Transient transfection assays using vascular endothelial cells revealed that site-directed mutations in the Sp1 binding element decreased tumor necrosis factor-alpha-induced activity of the VCAM1 promoter. The cytokine-induced enhancer of the VCAM1 gene requires constitutively bound Sp1 and induced heterodimeric NF-kappa B for maximal promoter activity.

Lymphatic regulation of hematocrit during hypoxia in the toad Bufo woodhousei

Hypoxia rapidly increases hematocrit (Hct) in anuran amphibians by reducing plasma volume, but the mechanism(s) mediating this response is unknown. We tested the hypothesis that, during hypoxia, plasma volume is reduced by impaired lymph heart (LH) function, decreasing lymph flow into the circulation. In Bufo woodhousei, we measured the effects of hypoxia on Hct, lymph heart rate (LHR), LH pressure, the movement of dye from the dorsal lymph sac to the arterial blood, and flow through an open LH cannula. We also tested whether splenic contraction or cholinergic nerves contribute to the hypoxia-induced changes. Graded hypoxia between 21 and 4% O2 produced graded increases in Hct (P < 0.0001) and decreases in LHR (P = 0.01). Hypoxia reduced the rate of increase in arterial Evans blue concentration after injection into the dorsal lymph sac (P = 0.041) and decreased flow through an open LH cannula (P < 0.012). Hypoxia increased Hct and reduced LHR similarly in control, splenectomized, and sham-splenectomized toads. Atropine had no significant effect on Hct and LHR. These results indicate that the LHs play a regulatory role in hypoxia-induced hemoconcentration.

A porcine model for laparoscopic adrenalectomy

Laparoscopic adrenalectomy has been successfully performed and described in humans. Though it is presently not widely employed it offers tremendous potential for adrenal surgery. It remains, however, an advanced technique requiring demonstration and practice. The aim of this study is to develop a porcine model of adrenalectomy for teaching and advancing the technique applicable to human surgery. Five female pigs weighing 10-20 kg underwent bilateral adrenalectomy by the lateral approach using endotracheal intubation. The left adrenal was resected with the pig in the right decubitus position. The animal was repositioned to left decubitus and the right adrenal was resected. In each case four 10-mm trochars were placed over the respective flanks. There was no need to mobilize the colon or liver (in the pig model). The peritoneum over each gland was incised and the gland dissected in a cephalocaudal manner. The vessels were ligated and divided particularly those from the vena cava. Upon completion blood loss (< 100 cc) and operating times (mean 60 min for the left and 90 min for the right) were assessed and the animal was sacrificed. The glands were weighed (mean 1.23 g R and 1.15 g L) and measured. Using this model, experience is gained in positioning the subject as well as trocars, in fine dissection in a lateral orientation, and in techniques of hemostasis. Although porcine and human adrenal anatomy differ in some details the pig constitutes an excellent model for the development of the technical experience required to perform adrenalectomy in humans.

Diagnosis of persistent intestinal ischemia in the rabbit using proton magnetic resonance imaging

Noninvasive diagnosis of persistent intestinal ischemia remains an elusive goal. Magnetic resonance imaging (MRI) recognizes changes in tissue water content, and several authors have demonstrated increased intensity within 6 hours of intestinal ischemia. To simulate the clinical situation more closely, we studied the efficacy of MRI in differentiating ischemic from viable segments of bowel 24 hours after injury in a rabbit model. A segment of distal ileum was rendered ischemic by vascular isolation and ligation. Controls underwent sham operation without vascular ligation. After 24 hours, multislice transverse scans were done using both T1 and T2 weighting. Image intensity was calculated from the isolated loop (absolute intensity), and paraspinal muscle intensity was used as an internal standard to calculate relative intensity (isolated bowel/paraspinal muscle). Animals were killed and bowel necrosis was confirmed histologically. Both absolute and relative intensity were significantly higher in animals undergoing persistent intestinal ischemia. This was true using both T1 and T2 weighting. In a further group of rabbits using the same model, intensity was calculated both before and after intravenous gadolinium. No significant difference was seen between sham and ischemic animals. Our data show that (1) MRI can differentiate ischemic from viable bowel 24 hours after ischemic injury, and (2) the use of intravenous contrast does not improve accuracy. We conclude that MRI may represent a useful noninvasive technique for the diagnosis of persistent intestinal ischemia and that clinical studies should be initiated.

Laparoscopic-assisted vagotomy and distal gastrectomy

This is a report of the techniques used on and outcome for three patients who underwent laparoscopic-assisted vagotomy and distal gastrectomy for complicated peptic ulcer disease. The first patient had a Billroth I anastomosis in 2 h 42 min with an estimated blood loss of 200 ml. Oral fluids were started on day 3 and the diet progressed to a soft food by day 5. The patient was discharged 11 days after his gastrectomy following a transurethal prostatic resection on day 6. The second patient had a Billroth II anastomosis. The operation was completed in 4 h 40 min with an estimated blood loss of 350 ml. Oral fluids were commenced on the 1st postoperative day and the patient was tolerating a soft diet by day 4. The patient was discharged 5 days after his gastrectomy. The third patient had a Billroth I anastomosis with an estimated blood loss of less than 150 ml. The surgery took 2 h 35 min; the patient was tolerating oral fluids on the first postoperative day and was discharged on the 4th postoperative day on soft diet. Laparoscopic-assisted vagotomy and gastrectomy has the advantages of a minimal-access procedure without the risks of an intracorporeal anastomosis.

Perfragilins A and B, cytotoxic isoquinolinequinones from the bryozoan Membranipora perfragilis

Detailed spectroscopic and cytotoxicity data are reported for two new isoquinolinequinones, perfragilins A [1] and B [2], which were isolated from the bryozoan Membranipora perfragilis collected in South Australia. Both compounds, which are speculated to be of microbial origin, contain a relatively uncommon thiomethyl ether functionality.

Diagnosis of intestinal ischemia in the rat using magnetic resonance imaging

Noninvasive diagnosis of persistent ischemia after intestinal revascularization has remained an elusive goal. Because magnetic resonance imaging (MRI) can detect changes in tissue water, we studied its efficacy in differentiating ischemic from perfused intestine in an animal model. Six-week-old rats were subjected to (1) 30-min superior mesenteric artery (SMA) occlusion and reperfusion, (2) permanent SMA ligation, or (3) sham operation, and were then imaged for 90 min using a small-animal MRI scanner with T1 weighting (TR = 1000 msec, TE = 25 msec). In an additional group of rats, the experiment was repeated using a new contrast technique consisting of oral ferrite to decrease luminal signal and intravenous gadolinium to increase bowel wall signal. Mean abdominal intensity over the scanning period was calculated for each animal (n = 5 rats per experimental group). Definition of individual bowel loops was subjectively improved in animals scanned with intravenous and oral contrast. Mean abdominal intensity was significantly lower in ligated vs sham rats (43.90 +/- 8 vs 59.63 +/- 6 and 46.19 +/- 6 vs 54.26 +/- 6, with and without contrast, respectively). There was no significant difference in intensity between reperfused and sham animals. MRI differentiated persistently ischemic bowel from viable bowel in this model, both with and without the use of contrast. These data suggest that MRI may have a potential role in the noninvasive diagnosis of persistent intestinal ischemia.

Child, parent, and physician perceived satisfaction with pediatric outpatient visits

Patient satisfaction has been linked empirically to a variety of health care outcomes (e.g., treatment adherence). Unfortunately, there is a paucity of data regarding the assessment of children's satisfaction with pediatric care. This lack of instrumentation was the impetus for the development and preliminary validation of the Metro Assessment of Child Satisfaction (MACS). Findings indicated the MACS is internally consistent and easily administered and understood by children as young as 6 years of age. Factor analysis yielded four distinct factors that appear to be statistically valid and clinically meaningful. Findings are discussed in relation to maternal ratings of satisfaction and physician perceptions of patient and parent satisfaction.

The cell-type-specific activator region of c-Jun juxtaposes constitutive and negatively regulated domains

Dissection of the cell-type-specific activation region in c-Jun reveals two functionally separable regulatory subdomains. One subdomain (a1) functions as a transcriptional activator; adjacent to it is a newly identified domain (epsilon) which, together with the previously defined delta region, interacts with a cellular factor that modulates the action of a1. Mutants that lack epsilon are constitutively active and do not interact with the cell-type-specific repressor, whereas mutants that have sustained changes in a1 exhibit a reduced trans-activation potential but retain the ability to interact with the repressor. This bipartite and modular organization of the a1/epsilon domain is further established by demonstrating that a1 can be replaced by the heterologous acidic activator of VP16 and retain proper negative regulation by the cell-specific c-Jun inhibitor along with epsilon and delta. Repression of Jun activity by the inhibitor is not caused by a change in stability, nuclear localization, or DNA-binding activity of the protein. Instead the inhibitor apparently regulates transcriptional activation by interacting directly with delta/epsilon and perhaps masking the a1 domain. These studies suggest that multifunctional activation domains, which are structurally complex, may play an important role in the mechanisms that govern inducible tissue-specific gene expression.

Characterization of the mmsAB operon of Pseudomonas aeruginosa PAO encoding methylmalonate-semialdehyde dehydrogenase and 3-hydroxyisobutyrate dehydrogenase

A 5417-base pair (bp) region of Pseudomonas aeruginosa PAO chromosomal DNA containing the mmsAB operon and an upstream regulatory gene (mmsR) has been cloned and characterized. The operon contains two structural genes involved in valine metabolism: mmsA, which encodes methylmalonate-semialdehyde dehydrogenase; and mmsB, which encodes 3-hydroxyisobutyrate dehydrogenase. mmsA and mmsB share the same orientation and are separated by a 16-bp noncoding region. The transcriptional start site for the operon has been pinpointed to a cytidine residue located 77 bp from the translational start site of the operon. mmsR is located on the opposite strand and begins 134 bp from the translational start site of mmsA. MmsR has been identified as a member of the XylS/AraC family of transcriptional regulators and appears to act as a positive regulator of the mmsAB operon. Sequence comparison of MmsA to other proteins in the data bases revealed that MmsA belongs to the aldehyde dehydrogenase (NAD+) superfamily. MmsB shares a 44% amino acid identity with 3-hydroxyisobutyrate dehydrogenase from rat liver. Mutants with insertionally inactivated mmsR, mmsA, and mmsB grow slowly on valine/isoleucine medium and exhibit reduced enzyme activity in cell-free extracts compared to P. aeruginosa PAO.

Acceptability of interventions for childhood depression

Using a case description methodology, this study examined the effects of behavior problem severity, intervention type, and subject race on mothers' acceptability ratings of five interventions used to treat childhood depression. Results indicated that (a) all psychological (behavioral or cognitive-behavioral) interventions were rated more acceptable than pharmacological treatment; (b) among the psychological interventions, the social skills intervention was the least preferred; (c) acceptability of treatments varied as a function of subject race; and (d) severity of depressive symptoms failed to influence acceptability ratings significantly. Psychometric support was found for a revised measure of acceptability (Abbreviated Acceptability Rating Profile; AARP) developed in the context of the present study. Implications of the findings for consultation are discussed.

v-Src and EJ Ras alleviate repression of c-Jun by a cell-specific inhibitor

The AP-1 family of transcription factors, which includes the proto-oncogene products c-Jun and c-Fos, controls the stimulation of cellular genes by growth factors and the expression of oncogenes, including src and ras. Transcriptional activation by c-Jun is regulated by a cell-type-specific inhibitor that represses the activity of a transcriptional activation domain (A1) of c-Jun by operating through the adjacent negative regulatory region (delta). Here we show that cotransfection of the src or ras oncogene enhances the transcriptional activity of a GAL4:c-Jun hybrid that includes the delta-A1 region of c-Jun, suggesting that the DNA binding and dimerization domain of c-Jun is not required for stimulation by Src or Ras. Moreover, induction of c-Jun activity by Src and Ras occurs in cell lines containing the c-Jun inhibitor but not in a cell line lacking it. The region in c-Jun essential for the stimulatory action of these oncogenes maps to domain A1. These findings suggest the existence of signal-transduction pathways that result in an increase in transcriptional activity of c-Jun and AP-1 by disrupting the c-Jun:inhibitor interaction.

Circadian variation of heart rate is affected by environment: a study of continuous electrocardiographic monitoring in members of a symphony orchestra

Twenty four hour ambulatory ST segment monitoring was performed on 48 members (43 players and five members of the management/technical team) of the British Broadcasting Corporation (BBC) symphony orchestra without a history of cardiac disease. This period included final rehearsals and live performances (for audience and radio) of music by Richard Strauss and Mozart at the Royal Festival Hall (n = 36) and Rachmaninov and Tchaikovsky at the Barbican Arts Centre (n = 21). During the period of monitoring one person (2%) had transient ST segment changes. Mean heart rates were significantly higher during the live performances than during the rehearsals. Mean heart rates during the live performance of Rachmaninov and Tchaikovsky were significantly higher than during Strauss and Mozart in those (n = 6) who were monitored on both occasions. Mean heart rates in the management and technical team were higher than those of the players. The recognised circadian pattern of heart rate, with a peak in the morning waking hours, was altered similarly during both concert days, with a primary peak occurring in the evening hours and a lesser peak in the morning for both musicians and management/technical staff. This study showed that environmental factors are of primary importance in defining the circadian pattern of heart rate. This has important implications when identifying peak periods of cardiovascular stress and tailoring drug treatment for patients with angina pectoris.

Ambulatory ST segment monitoring in the assessment of patients following PTCA

In this article we discuss the place of ambulatory ST-segment monitoring in the investigation of the patient following coronary angioplasty. Particular attention is focused on the relationship between the results of exercise testing (the standard technique in the evaluation of the post-angioplasty patient) and ambulatory ST-segment monitoring, in order to assess whether ST-segment monitoring might contribute further information in the identification of residual or recurrent ischaemia.

Ischemia in the ambulatory setting--the total ischemic burden: relation to exercise testing and investigative and therapeutic implications

To establish the relation between treadmill exercise testing and ambulatory St segment monitoring in the detection of ischemia in patients with coronary artery disease, and to assess whether standard medical therapy affects any such relation, 277 patients with stable angina and angiographically documented coronary artery disease were studied with treadmill exercise testing and 48 h ambulatory ST segment monitoring. One hundred forty-six patients (52%) were studied while receiving no routine antianginal therapy, and 131 (48%) while receiving standard medical therapy. In 187 patients (67%) the exercise test was positive for ischemia. During 11,964 h of ambulatory monitoring, 881 episodes of ischemia (645 [73%] silent) were recorded, of which 809 (92%) occurred in patients with a positive exercise test. The mean heart rate at the onset of ischemic episodes during ambulatory monitoring was significantly less than that at the onset of 1 mm ST segment depression during exercise testing (94.5 versus 105.9 beats/min, p less than 0.0001). However, the frequency of ambulatory ischemic episodes was strongly related to a positive exercise test (p less than 0.001), and this relation was similar for both silent and painful ischemia (p less than 0.0001 for both) and in patients who were and were not receiving therapy (p less than 0.0001 for both). The total duration of ischemia was similarly related to a positive exercise test (p less than 0.0001). Only one patient with a negative exercise test had frequent (greater than 5/day) episodes of ischemia on ambulatory monitoring and had documented coronary artery spasm. Thus, exercise testing identifies the majority of patients likely to have significant ischemia during their daily activities.(ABSTRACT TRUNCATED AT 250 WORDS)

Stimulation of rat B-lymphocyte proliferation by corticotropin-releasing factor

The mitogenic effect of corticotropin-releasing factor (CRF) on rat lymphocytes was investigated. When rat splenocytes were cultured for 48 hr with CFR, a dose-dependent increase in incorporation of 3H-thymidine (3H-Tdr) was observed, with a maximal response at 10 nM CRF. Comparison of the proliferative effect of CRF on enriched populations of B lymphocytes, T lymphocytes, or macrophages revealed that only B lymphocytes responded following treatment with CRF. When lymphocytes derived from different lymphoid tissues were compared, CRF had a greater proliferative effect on lymphocytes derived from gut-associated lymphoid tissue (mesenteric lymph nodes and Peyer's patches) than on lymphocytes from spleen or inguinal lymph nodes; CRF had no effect on thymocytes. Synthetic fragments of CRF were used to determine which portions of the peptide are recognized by lymphocytes. The C-terminal fragments alpha-helical CRF9-41 and CRF21-41 were as potent as native CRF in stimulating B-lymphocyte proliferation, whereas CRF1-20 did not stimulate proliferation. The activity of these peptides suggests that CRF stimulates lymphocyte proliferation by cellular recognition of structural determinants in the C-terminal one-half of the peptide.

Diurnal variation of pulmonary artery pressure in chronic heart failure

Variation in pulmonary artery pressure has important consequences for the interpretation of isolated pressure measurements in patients with chronic heart failure. To investigate the nature of diurnal variation in pulmonary artery pressure in chronic heart failure, eight angina-free men (aged 50-72 years) with treated chronic heart failure caused by ischaemic heart disease underwent continuous ambulatory pulmonary artery pressure recording by a transducer tipped catheter. The mean (1 SD) daytime pulmonary artery pressure was 29.6 (5.0) mm Hg systolic and 13.7 (5.6) mm Hg diastolic. The mean change in pressure from day to night was +5.1 (3.2) mm Hg systolic and +3.8 (1.7) mm Hg diastolic; and the mean change from standing to lying +9.3 (2.3) mm Hg systolic and +6.4 (2.1) mm Hg diastolic. In six of the eight patients there was considerable rise in pulmonary artery pressure at night, but in the two patients with the most severe symptoms there was no nocturnal rise. In patients with chronic heart failure, nocturnal pulmonary artery pressure is not determined by postural change alone. But interpretation of isolated pulmonary artery pressure measurements must take the posture of the patient into account.

Silent myocardial ischaemia in patients referred for coronary bypass surgery because of angina: a comparison with patients whose symptoms were well controlled on medical treatment

The frequency and characteristics of silent ischaemia were prospectively studied in 114 patients with confirmed coronary artery disease and angina. Fifty seven patients who had angina that was not adequately controlled by standard medications were referred for elective coronary artery bypass surgery (group 1). Fifty seven other patients had symptoms that were well controlled on medical treatment (group 2). Patients underwent treadmill exercise testing (n = 109) and 48 hours of ambulatory ST segment monitoring (total 5125 hours). Patients in group 1 had more severe coronary artery disease and a shorter time to 1 mm ST segment depression and maximal exercise. Twenty two patients in group 1 (38%) and 16 in group 2 (28%) had greater than or equal to 1 episode of silent ischaemia during 48 hours of ST monitoring. There was no significant difference in the mean frequency of silent ischaemic episodes in 24 hours between the two groups (group 1 0.72 v group 2 0.64); however, the mean frequency of painful ischaemic episodes in 24 hours was greater in group 1 patients (0.51) than in group 2 (0.11). In both groups the frequency of silent ischaemia was significantly related to a positive exercise test, as was the total duration of silent ischaemia. The circadian variation of silent ischaemia showed a peak of episodes in the evening in both groups. The frequency of silent ischaemia in patients with coronary artery disease and angina receiving standard antianginal medications was not related to the severity of symptoms, but was significantly related to a positive exercise test. Thirty three percent of the patients studied had evidence of silent ischaemia during 48 hours of ambulatory ST segment monitoring; however, only four patients (3.5%) had frequent (>/=5) daily episodes of silent ischaemia.

A new exercise test for the assessment of heart failure: use of a self powered treadmill

Time limited exercise on a self powered treadmill was evaluated as a method of assessing functional capacity in patients with mild heart failure. The characteristics of the treadmill were established by exercising 11 controls at three speeds and two inclinations and comparing oxygen consumption with that on a motorised treadmill under the same conditions. Oxygen consumption on the self powered treadmill at an equivalent speed and inclination was significantly higher because of the work needed to overcome the friction of the belt. Unlike a conventional treadmill, increasing the gradient on the self powered treadmill did not increase oxygen consumption. The distance walked in 12 minutes on the self powered treadmill was measured in eight patients with mild heart failure and ten controls. Maximal oxygen consumption was measured in the same group on a conventional treadmill by a mass spectrometer. There was a significant correlation between the distance walked and maximum oxygen consumption. In patients with mild heart failure the distance travelled in 12 minutes on a self powered treadmill provides a practical, inexpensive, and sensitive method of assessing functional capacity.

Cough flow-volume relationships in normal and asthmatic children

The flow-volume profile of a maximum voluntary cough resembles that of a maximum expiratory flow-volume (MEFV) curve with superimposed transient peak flows at the onset of each cough effort and portions of zero flow corresponding to periods of glottis closure. A straight line (the cough slope) can be drawn through the transient peak flows, and the ratio of MEFV-equivalent flow to the cough peak flow can be calculated. This cough ratio has been shown to fall during adult life and may be related to changes in airway compliance and cross-sectional area with age. The present study investigated the cough ratio, cough slope, and maximum flows measured from the cough flow-volume curve in a group of normal children aged 7 to 16 years. Maximum flows and the cough slope increased with height, but the cough ratio did not change with growth or age. In a similar group of asthmatic children, baseline measurements of cough showed a reduction in cough peak flow rates, MEFV-equivalent flow, and the cough ratio. These changes are related to alterations in airway compliance and cross-sectional area and are partly reversed following inhalation of a bronchodilator.

Circadian variation of total ischaemic burden and its alteration with anti-anginal agents

6264 hours of ambulatory ST segment monitoring of 150 unselected patients with proven coronary artery disease, who were off all routine anti-anginal treatments, showed 598 ischaemic episodes, of which 446 (75%) were silent (symptom-free). Most (68%) ischaemic episodes occurred between 0730 and 1930, with a peak in the morning and a lesser peak in the evening. Two subgroups were studied further in double-blind controlled trials: 33 patients had a total of 1313 hours of ST segment monitoring while treated with nifedipine; and 41 patients a total of 1581 hours while treated with atenolol. Nifedipine did not alter the circadian pattern of ischaemic episodes; atenolol abolished the morning peak, and the peak incidence of ischaemia then occurred in the evening. Circadian patterns for total duration of ischaemic episodes corresponded closely to those of episodes of ischaemia, and were similarly altered by treatment. The circadian pattern of silent ischaemic episodes and their total duration were very similar to those of total ischaemia for the group as a whole and the different subgroups. This circadian distribution of ischaemic episodes and the observed changes with treatment resemble the reported circadian variation of acute myocardial infarction and sudden death.

Controlled trial of clinical utility of serum salicylate monitoring in rheumatoid arthritis

A crossover double-blind controlled trial was performed on 36 patients with rheumatoid arthritis to assess the necessity for serum salicylate monitoring in determining optimal dosage. There was no clinically or statistically significant increase in the clinical improvement of patients associated with serum monitoring but potentially toxic serum levels occurred without tinnitus when serum monitoring was not used.