The influence of experimental anterior knee pain during running on electromyography and articular cartilage metabolism.

OBJECTIVE: To determine whether anterior knee pain (AKP), during running, acutely affects lower-extremity electromyography (EMG) and articular cartilage metabolism. METHODS: A within-subjects design was used. Each of 12 able-bodied subjects ran on a treadmill for 30 min for three different sessions: control (no infusion), sham (0.9% NaCl infusion into the involved-leg infrapatellar fat pad), and pain (5.0% NaCl infusion into the involved-leg infrapatellar fat pad). Bilateral surface EMG was monitored for the vastus medialis (VM), vastus lateralis (VL), and gastrocnemius (GA). Serum cartilage oligomeric matrix protein (COMP) concentration was determined before, after, and 60 min after the run. A functional analysis approach was used to compare EMG amplitude, across the entire stance phase, between sessions and legs. Mixed-model analysis of covariance was used to compare serum COMP concentration between sessions, across time. RESULTS: Relative to the uninvolved leg, greater involved-leg VL and GA EMG amplitude existed during midstance for the sham and control sessions (P < 0.01). During the painful session, however, involved-leg VM, VL, and GA EMG amplitude was 5-10% less than for the uninvolved leg. COMP concentration immediately post-run was 14% and 21% greater than pre-run (P = 0.01) and 60 min post-run concentrations (P < 0.01), respectively. Session, however, did not significantly influence COMP. CONCLUSION: During a 30-min run, AKP acutely alters midstance VM, VL, and GA EMG amplitude. AKP during a 30-min run does not, however, acutely influence articular cartilage metabolism.

Transgenic avian-derived recombinant human interferon-alpha2b (AVI-005) in healthy subjects: an open-label, single-dose, controlled study.

BACKGROUND/AIMS: This study characterized the safety and pharmacological properties of AVI-005, a novel glycosylated recombinant human interferon-alpha2b produced from the egg whites of chickens transfected with human cDNA. METHODS: 18 healthy volunteers received single subcutaneous rising doses (0.5, 1.66 or 5 million international units, MIU) of AVI-005. A randomized parallel comparator group of 10 subjects received 5 MIU of unglycosylated IFN-alpha2b (Intron A). The pharmacokinetic parameters t1/2, tmax, Cmax, AUC0-24h, Vd, and clearance were compared between AVI-005 and unglycosylated IFN-alpa2b. RESULTS: At equipotent doses, AVI-005 had a larger AUC0-24h than the control interferon. Pharmacodynamic markers ofneopterin and beta2-microglobulin for the two treatments were similar. These markers were increased by AVI-005 in a dose-dependent manner. Pharmacodynamic responses to treatment with AVI-005 were shown by the change in mRNA expression for interferon inducible protein kinase and 2'5'-oligoadenylate synthetase. Adverse events in the two groups were qualitatively and quantitatively similar. CONCLUSION: AVI-005 demonstrates biological activity and pharmaco-kinetic properties in humans that support further development.

Clinical correlates and reference intervals for pulmonary artery systolic pressure among echocardiographically normal subjects.

BACKGROUND: Data in normal human subjects on the factors affecting pulmonary artery systolic pressure (PASP) are limited. We determined the correlates of and established a reference range for PASP as determined by Doppler transthoracic echocardiography (TTE) from a clinical echocardiographic database of 102 818 patients, of whom 15 596 (15%) had a normal Doppler TTE study. METHODS AND RESULTS: A normal TTE was based on normal cardiac structure and function during complete Doppler TTE studies. The PASP was calculated by use of the modified Bernoulli equation, with right atrial pressure assumed to be 10 mm Hg. Among TTE normal subjects, 3790 subjects (2432 women, 1358 men) from 1 to 89 years old had a measured PASP. The mean PASP was 28.3+/-4.9 mm Hg (range 15 to 57 mm Hg). PASP was independently associated with age, body mass index (BMI), male sex, left ventricular posterior wall thickness, and left ventricular ejection fraction (P<0.001). The estimated upper 95% limit for PASP among lower-risk subjects was 37.2 mm Hg. A PASP >40 mm Hg was found in 6% of those >50 years old and 5% of those with a BMI >30 kg/m(2). CONCLUSIONS: Among 3790 echocardiographically normal subjects, PASP was associated with age, BMI, sex, wall thickness, and ejection fraction. Of these subjects, 28% had a PASP >30 mm Hg, and the expected upper limit of PASP may include 40 mm Hg in older or obese subjects. These findings support the use of age- and BMI-corrected values in establishing the expected normal range for PASP.

Protein kinase C-mediated down-regulation of beta(2)-adrenergic receptor and gene expression in rat C6 glioma cells.

We investigated the regulation of beta(2)-adrenergic receptors (beta(2)AR) by protein kinase C (PKC) in rat C6 glioma cells at the levels of receptor activity, protein expression and gene expression. Cells exposed to 4beta-phorbol-12-myristate-13-acetate (PMA), a potent activator of PKC, exhibited a time- and concentration-dependent decrease in beta(2)AR binding activity. Maximum down-regulation was approximately 50% by 24 h and western blot analysis revealed a parallel decrease in beta(2)AR protein. In addition, PMA treatment resulted in an acute desensitization of beta(2)AR-stimulated cyclic AMP response prior to any reduction in receptor levels. PMA exposure also affected steady-state beta(2)AR mRNA levels in a time-dependent, biphasic manner. During the first 4 h, levels decreased by approximately 60% and then slowly recovered to approximately 75% of control by 24 h. As the reduction in receptor mRNA was not due to a decrease in its stability, we examined beta(2)AR gene transcription by nuclear run-on assays. Transcriptional activity in nuclei from C6 cells treated with PMA for 2 h was reduced by 70% compared to controls. Thus PKC can regulate beta(2)AR at least two levels: the first being an acute desensitization of receptor function, and the second being a more prolonged repression of receptor gene transcription that in turn results in decreased receptor expression.

Differential effects of mitomycin C and doxorubicin on P-glycoprotein expression.

Previous studies have demonstrated that mitomycin C (MMC) and other DNA cross-linking agents can suppress MDR1 (multidrug resistance 1) gene expression and subsequent functional P-glycoprotein (Pgp) expression, whereas doxorubicin and other anthracyclines increase MDR1 gene expression. In the present study, with stably transfected Madin-Darby canine kidney C7 epithelial cells expressing a human Pgp tagged with green fluorescent protein under the proximal human MDR1 gene promoter, we demonstrated that MMC and doxorubicin have differential effects on Pgp expression and function. Doxorubicin caused a progressive increase in the cell-surface expression of Pgp and function. In contrast, MMC initially increased plasma membrane expression and function at a time when total cellular Pgp was constant and Pgp mRNA expression had been shown to be suppressed. This was followed by a rapid and sustained decrease in cell-surface expression at later times, presumably as a consequence of the initial decrease in mRNA expression. These studies imply that there are at least two independent chemosensitive steps that can alter Pgp biogenesis: one at the level of mRNA transcription and the other at the level of Pgp trafficking. Understanding the combined consequences of these two mechanisms might lead to novel chemotherapeutic approaches to overcoming drug resistance in human cancers by altering either Pgp mRNA expression or trafficking to the membrane.

A comparison of complete blood replacement with varying hematocrit levels on neurological recovery in a porcine model of profound hypothermic (<5 degrees C) circulatory arrest.

Profound hypothermia (<5 degrees C) may afford better neurological protection after circulatory arrest; however, there are theoretical concerns related to microcirculatory sludging of blood components at these ultra-low temperatures. We hypothesized that at temperatures <5 degrees C, complete blood replacement results in superior neurological outcome. Twelve Yorkshire pigs (30 kg) underwent thoracotomy, cardiopulmonary bypass (CPB), and were randomly assigned to one of three target hematocrits during circulatory arrest: 0%, 5%, 15%. Hextend (6% hetastarch in a balanced electrolyte vehicle) was used for the CPB prime and as an exchange fluid. Animals were cooled to a temperature <5 degrees C, underwent 1-h circulatory arrest, and were warmed to 35 degrees C with administration of blood to increase the hematocrit to >25% before separation from CPB. The primary outcome, peak postoperative neurobehavioral score, was compared between groups. The 0% group (mean +/- SD) had significantly (P: < 0.02) better neurobehavioral scores than the 5% and 15% groups (6.0 +/- 2.9 vs 1.3 +/- 1.0 and 1.5 +/- 0.6) respectively. Other variables (e.g., intracranial pressure) were similar between groups. In a porcine model of profound hypothermia (<5 degrees C) and circulatory arrest, complete blood replacement resulted in superior neurological outcome. This finding suggests that at ultralow temperatures, the presence of some blood component (e.g., erythrocytes, leukocytes) may be deleterious.

Inhibition of CCR5-dependent HIV-1 infection by hairpin ribozyme gene therapy against CC-chemokine receptor 5.

CCR-5 is a major cellular coreceptor for R5 strains of HIV-1. Individuals carrying a homozygous 32-base-pair deletion in this gene are apparently healthy and are relatively resistant to HIV-1 infection. Since CCR5 appears to be dispensable for the host, but important for initial HIV-1 infection, CCR5 mRNA is an excellent therapeutic target for inhibiting HIV-1 replication via ribozyme knockout. We report here that hairpin ribozymes are able to reduce cellular CCR5 mRNA and cell surface CCR5 when stably introduced into PM1 cells by transduction with recombinant adenoassociated viral vector. The ribozymes effectively protect the cells from infection by R5 HIV-1 strains or non-syncytium-inducing clinical isolates commensurate with a reduction in CCR5 mRNA. These results suggest a novel gene therapy approach to preventing or slowing the disease progression of HIV-1 infection.

Identification of eIF2Bgamma and eIF2gamma as cofactors of hepatitis C virus internal ribosome entry site-mediated translation using a functional genomics approach.

The 5'-untranslated region of hepatitis C virus (HCV) is highly conserved, folds into a complex secondary structure, and functions as an internal ribosome entry site (IRES) to initiate translation of HCV proteins. We have developed a selection system based on a randomized hairpin ribozyme gene library to identify cellular factors involved in HCV IRES function. A retroviral vector ribozyme library with randomized target recognition sequences was introduced into HeLa cells, stably expressing a bicistronic construct encoding the hygromycin B phosphotransferase gene and the herpes simplex virus thymidine kinase gene (HSV-tk). Translation of the HSV-tk gene was mediated by the HCV IRES. Cells expressing ribozymes that inhibit HCV IRES-mediated translation of HSV-tk were selected via their resistance to both ganciclovir and hygromycin B. Two ribozymes reproducibly conferred the ganciclovir-resistant phenotype and were shown to inhibit IRES-mediated translation of HCV core protein but did not inhibit cap-dependent protein translation or cell growth. The functional targets of these ribozymes were identified as the gamma subunits of human eukaryotic initiation factors 2B (eIF2Bgamma) and 2 (eIF2gamma), respectively. The involvement of eIF2Bgamma and eIF2gamma in HCV IRES-mediated translation was further validated by ribozymes directed against additional sites within the mRNAs of these genes. In addition to leading to the identification of cellular IRES cofactors, ribozymes obtained from this cellular selection system could be directly used to specifically inhibit HCV viral translation, thereby facilitating the development of new antiviral strategies for HCV infection.

Identification and validation of a gene involved in anchorage-independent cell growth control using a library of randomized hairpin ribozymes.

We have developed a library of hairpin ribozyme genes that can be delivered and expressed in mammalian cells with the purpose of identifying genes involved in a specific phenotype. By applying the appropriate phenotypic selection criteria in tissue culture, we can enrich for ribozymes that knock down expression of an unknown gene or genes in a particular pathway. Once specific ribozymes are selected, their target binding sequence is used to identify and clone the target gene. We have applied this technology to identify a putative tumor suppressor gene that has been activated in HF cells, a nontransformed revertant of HeLa cells. Using soft agar growth as the selection criteria for gain of transformation, we have isolated ribozymes capable of triggering anchorage-independent growth. Isolation of one of these ribozymes, Rz 568, led to the identification and cloning of the human homologue of the Drosophila gene ppan, a gene involved in DNA replication, cell proliferation, and larval development. This novel human gene, PPAN, was verified as the biologically relevant target of Rz 568 by creating five additional "target validation" ribozymes directed against additional sites in the PPAN mRNA. Rz 568 and all of the target validation ribozymes reduced the level of PPAN mRNA in cells and promoted anchorage-independent growth. Exogenous expression of PPAN in HeLa and A549 tumor cells reduced their ability to grow in soft agar, underscoring its role in regulating anchorage-dependent growth. This study describes a novel method for gene discovery where the intracellular application of hairpin ribozyme libraries was used to identify a novel gene based solely on a phenotype.

Inhibition of interleukin-1beta (IL-1beta) production in human cells by ribozymes against IL-1beta and IL-1beta converting enzyme (ICE).

We and others have shown previously that hairpin ribozyme genes, when stably expressed in cells, can reduce the steady-state levels of target mRNA and their cognate proteins. Despite this capability, ribozymes have not been as widely used in knockdown experiments as one might expect, probably because specific rules governing the selection of ribozymes that will have high activity have not been described. In this report, we show that parallel screening of less than 10 ribozyme expression constructs, with no advanced knowledge of cleavage activity or preselection, can efficiently identify knockdown ribozymes. This empirical selection study, which used interleukin-1beta (IL-1beta) and IL-1beta converting enzyme (ICE) as example targets, resulted in (1) the rapid identification of ribozymes that can reduce the production of IL-1beta in THP-1 cultures by 10-fold and (2) the consequent direct generation of stable knockdown cell lines. We conclude, based on these and similar studies, that parallel screening of ribozyme constructs could be used in high throughput gene functional analysis programs as a means of rapidly generating specific knockdown cell lines.

Identification and developmental expression of the estrogen receptor alpha and beta in the baboon fetal adrenal gland.

We have previously shown that estrogen regulates the development and function of the fetal and definitive/transitional zones of the primate fetal adrenal gland. Thus, during baboon pregnancy estrogen acts directly on the fetal zone to suppress ACTH-stimulated dehydroepiandrosterone (DHA) formation, potentially to modulate C19-steroid production and consequently placental estrogen synthesis. It is proposed that this action of estrogen is mediated by the estrogen receptor. Therefore, in the present study a developmental approach was used to determine whether the messenger RNA (mRNA) and protein for the estrogen receptor were expressed in the fetal and definitive/transitional zones ofthe baboon fetal adrenal gland at mid (day 100) and late (day 170) gestation (term = 184 days). Estrogen receptor alpha mRNA levels, determined by competitive RT-PCR, were approximately 7-fold greater (P < 0.02) in the fetal adrenal of late (187.8+/-40.3 attomoles/microg RNA) compared with mid (27.4+/-5.4 attomoles/microg RNA) gestation. Moreover, estrogen receptor alpha mRNA expression, determined by quantitative in situ hybridization, was approximately 2.5-fold greater (P < 0.05) in the definitive/transitional zones (21.6+/-0.5 silver grains/0.025 mm2) than in the fetal zone (8.3+/-1.5 grains/0.025 mm2) late in gestation. The mRNA for the beta-isoform of the estrogen receptor was also expressed in the baboon fetal adrenal cortex. There was a gradient of immunocytochemical staining for the estrogen receptor alpha and beta proteins, with extensive immunoreactivity for both isoforms in the definitive zone and lower staining in the transitional zone and the fetal zone. In summary, the results of the present study show that estrogen receptor alpha and beta were expressed in the fetal and definitive/transitional zones of the baboon fetal adrenal cortex at mid and late gestation. The presence of the estrogen receptor provides a mechanism for mediating the action of estrogen in modulating ACTH-dependent and cortical zone-specific development and function of the primate fetal adrenal gland.

Development of the baboon fetal adrenal gland: regulation of the ontogenesis of the definitive and transitional zones by adrenocorticotropin.

Throughout gestation, the primate fetal adrenal gland is comprised of the fetal zone, which expresses the P-450 17alpha-hydroxylase-C17,20 lyase (P-450c17) enzyme that catalyzes the synthesis of C19 steroids used for placental estrogen production. The development of the transitional zone comprised of cortical cells that express the P-450c17 and the 3beta-hydroxysteroid dehydrogenase-isomerase (3betaHSD) enzymes for cortisol production, and the definitive zone, which expresses 3betaHSD, but not P-450c17, for mineralocorticoid synthesis, does not occur until relatively late in gestation. Although ACTH is considered essential to fetal adrenal growth and function, the role that ACTH has in the development of the transitional and definitive zones, is less clear. To answer this question, the width of these zones was determined by immunocytochemical expression of P-450c17 and/or 3betaHSD in fetal adrenal glands obtained on day 100 (mid) of gestation (term = day 184) from baboons in which ACTH was administered to the fetus on days 95-99 of gestation or on day 165 (late) of gestation from baboons in which fetal ACTH was suppressed by treatment of the mother and fetus with betamethasone on days 150-164 of gestation. At midgestation, the fetal adrenal was comprised almost exclusively of fetal zone cells and a small definitive zone (38 +/- 2 microm in width), but was essentially devoid of a transitional zone (7 +/- 2 microm). Treatment with ACTH enhanced (P < 0.05) the width of the transitional zone (67 +/- 4 microm), but not the size of the definitive zone (10 +/- 4 microm). In late gestation, the width of the definitive zone, although 2-fold greater than that on day 100, was smaller (P < 0.05) than that of the transitional zone (120 +/- 15 microm), which greatly exceeded that at midgestation. Treatment with betamethasone in late gestation eliminated the transitional zone, but had no effect on the size of the definitive zone (120 +/- 8 microm). These findings indicate that the development of the baboon fetal adrenal transitional zone late in gestation is dependent on fetal pituitary ACTH. In contrast, the ontogenesis of the definitive zone at midgestation and its growth in late gestation occur in the relative absence of ACTH.

Lack of evidence of an association between mitral-valve prolapse and stroke in young patients.

BACKGROUND: Previous studies have reported a high prevalence of mitral-valve prolapse among patients with embolic stroke (28 to 40 percent), especially among young patients (those < or =45 years old); this finding has practical implications for prophylaxis. However, diagnostic criteria for prolapse have changed and are now based on three-dimensional analysis of the shape of the valve; use of the current criteria reduces markedly the frequency of such a diagnosis and increases its specificity. Previously described complications must therefore be reconsidered. METHODS: In a case-control study, we reviewed data on 213 consecutive patients 45 years old or younger with documented ischemic stroke or transient ischemic attack between 1985 and 1995; they underwent complete neurologic and echocardiographic evaluations. The prevalence of prolapse in these patients was compared with that in 263 control subjects without known heart disease, who were referred to our institution for assessment of ventricular function before receiving chemotherapy. RESULTS: Mitral-valve prolapse was present in 4 of the 213 young patients with stroke (1.9 percent), as compared with 7 of the 263 controls (2.7 percent); prolapse was present in 2 of 71 patients (2.8 percent) with otherwise unexplained stroke. The crude odds ratio for mitral-valve prolapse among the patients who had strokes, as compared with those who did not have strokes, was 0.70 (95 percent confidence interval, 0.15 to 2.80; P=0.80); after adjustment for age and sex, the odds ratio was 0.59 (95 percent confidence interval, 0.12 to 2.50; P=0.62). CONCLUSIONS: Mitral-valve prolapse is considerably less common than previously reported among young patients with stroke or transient ischemic attack, including unexplained stroke, and no more common than among controls. Using more specific and currently accepted echocardiographic criteria, therefore, we could not demonstrate an association between the presence of mitral-valve prolapse and acute ischemic neurologic events in young people.

Functional capacity of fetal zone cells of the baboon fetal adrenal gland: a major source of alpha-inhibin.

We have shown that ACTH receptor mRNA expression and steroidogenesis were increased in the transitional zone and decreased in the fetal zone of the baboon fetal adrenal in the second half of gestation. Thus, we proposed that there is a divergence in ACTH receptor-mediated zone-specific steroidogenesis within the fetal adrenal during mid to late gestation. We have also demonstrated that fetal serum alpha-inhibin levels decline with advancing development. It is possible, therefore, that the alpha subunit of inhibin provides a good marker of fetal zone cellular function and that the changes in circulating fetal alpha-inhibin with advancing pregnancy reflect ontogenetic changes in fetal adrenal cortical zone-specific cell function. However, it remains to be determined whether the fetal adrenal is a major source of circulating alpha-inhibin in the fetus and whether alpha-inhibin is expressed in the fetal, definitive, and/or transitional zones. Therefore, the current study compared fetal serum alpha-inhibin levels with immunocytochemical localization of alpha-inhibin in baboon fetal adrenals obtained on Days 60 (early), 100 (mid), and 165 or 182 (late) of gestation (term averages Day 184) from animals untreated or treated with betamethasone, which we previously demonstrated suppressed fetal pituitary ACTH and adrenal weight. Fetal serum alpha-inhibin levels (mean +/- SE) were greater (p < 0.05) at mid (5863 +/- 730 microliter eq/ml) than at late (3246 +/- 379) gestation and were reduced (p < 0. 05) by betamethasone. The inhibin alpha subunit was expressed in abundant quantities in the fetal adrenal cortex, but not in medulla, throughout gestation. At mid and late gestation, alpha-inhibin was expressed throughout the fetal adrenal cortex but most intensely in the innermost area of fetal zone cells. By late gestation, the fetal adrenal exhibited a gradient of alpha-inhibin expression. Thus, the outermost definitive zone cells were devoid of alpha-inhibin, the transitional zone exhibited a relatively low alpha-inhibin content, and fetal zone cells continued to exhibit extensive expression of alpha-inhibin. Betamethasone diminished the intensity of alpha-inhibin expression throughout the fetal adrenal cortex. These results indicate that the fetal adrenal fetal zone is a significant source of circulating alpha-inhibin in the baboon fetus and that alpha-inhibin provides a good marker to study the developmental regulation of fetal zone-specific adrenocortical function.

Comparison of Chinese and Caucasian families caregiving to children with cancer at home: Part I.

This 1-year, longitudinal comparative study of Chinese and Caucasian family caregiving for a child with cancer is reported in two parts. Part I describes data obtained from the initial interviews at diagnosis with Chinese and Caucasian families. Interviews revealed that Chinese families use supplemental care methods, Chinese families have fewer resources and are more isolated; Caucasian families emphasize emotional care; and family emotional coping patterns differed between the two groups. Measures of functional status of the child, the impact of the child's illness on the family, the symptomatic responses of the parents to the child's illness, and patterns of caregiving were also analyzed over the first year after diagnosis. There were no statistical differences between ethnic groups. General health was lower for the children with cancer than for chronically ill children. Part II reports on the results from the two following interviews during the first year after diagnosis.

Common themes and ethnic differences in family caregiving the first year after diagnosis of childhood cancer: Part II.

Chinese immigrant and North American white family caregiving for a child with cancer was compared in a 1-year study. This second of a two-part report describes interview results after first remission and at 1-year postdiagnosis. (The first part reported results of the initial interview and family function, symptom and caregiving inventories administered at diagnosis and at first remission). In follow-up interviews, the ill child remained the family priority in both groups, with sequelae for siblings and parents. All children were physically well cared for, with strict adherence to Western medical protocols. Cultural differences and immigrant status contributed to lower verbal expression of distress, more isolation, and lower attention to emotional distress for the Chinese. Caregiving emphases were dietary for the Chinese; emotional for the Caucasians. Differences over time in family caregiving and coping were determined by demands of care and evolving expertise. Care inclusive routines were established by most families by the second interview, in spite of extent of continued difficulties. Emotional care demands, concern for needs of siblings, and marital conflict increased over time. At 1 year, all families complained of emotional and physical fatigue and the need to adapt to a tentative future with their child.

Restricted diastolic opening of the mitral leaflets in patients with left ventricular dysfunction: evidence for increased valve tethering.

OBJECTIVES: We tested the hypothesis that patients with incomplete systolic mitral leaflet closure (IMLC: apically displaced coaptation) also have restricted diastolic leaflet opening that is independent of mitral inflow volume and provides evidence supporting increased leaflet tethering. BACKGROUND: Competing hypotheses for functional mitral regurgitation (MR) with IMLC include global left ventricular (LV) dysfunction per se (reduced leaflet closing force) versus geometric distortion of the mitral apparatus by LV dilation (augmented leaflet tethering). These are inseparable in systole, but restricted leaflet motion has also been observed in diastole, and attributed to reduced mitral inflow. METHODS: Diastolic mitral leaflet excursion and orifice area were measured by two-dimensional echocardiography in 58 patients with global LV dysfunction, 36 with and 22 without IMLC, compared with 21 normal subjects. The biplane Simpson's method was used to calculate LV ejection volume, which equals mitral inflow volume in the absence of aortic regurgitation. RESULTS: The diastolic mitral leaflet excursion angle was markedly reduced in patients with IMLC compared with those without IMLC, whose ventricles were smaller, and normal subjects (17 +/- 10 degrees vs. 58 +/- 13 degrees vs. 67 +/- 8 degrees, p < 0.0001). Excursion angle was dissociated from mitral inflow volume (r2 = 0.04); excursion was reduced in patients with IMLC despite a normal inflow volume in the larger ventricles with MR (60 +/- 25 vs. 61 +/- 12 ml in normal subjects, p = NS), and excursion was nearly normal in patients without IMLC despite reduced inflow volume (40 +/- 10 ml, p < 0.001 vs. normal subjects). The anterior leaflet when maximally open coincided well with the line connecting its attachments to the anterior annulus and papillary muscle tip (angular difference = 3 +/- 7 degrees vs. 25 +/- 9 degrees vs. 32 +/- 10 degrees in patients with and without IMLC vs. normal subjects, p < 0.0001). In patients with IMLC, the leaflet tip orifice was smaller in an anteroposterior direction but wider than in the other groups, giving a normal total area (6.8 +/- 1.8 vs. 7.1 +/- 1.2 vs. 6.9 +/- 0.8 cm2, p = NS). CONCLUSIONS: Patients with LV dysfunction and systolic IMLC also have restricted diastolic leaflet excursion that is independent of inflow volume, coincides with the tethering line connecting the annulus and papillary muscle and reflects limitation of anterior motion relative to the posteriorly placed papillary muscles without a decrease in total orifice area. These observations are consistent with increased tethering by displaced mitral leaflet attachments in the dilated ventricles of patients with IMLC that can restrict both diastolic opening and systolic closure.

Effect of maternal betamethasone administration at midgestation on baboon fetal adrenal gland development and adrenocorticotropin receptor messenger ribonucleic acid expression.

Although fetal pituitary ACTH is important to fetal adrenal growth and steroidogenesis in the second half of primate pregnancy, its role in adrenal development and function has not been established in vivo in the first half of gestation. In the present study, therefore, baboons were treated at midgestation with betamethasone to determine the effect of fetal pituitary ACTH on fetal adrenal growth, development, and ACTH receptor and P-450 enzyme messenger ribonucleic acid (mRNA) levels. The administration of betamethasone to baboon mothers on days 60-99 of gestation (term = 184 days) decreased fetal pituitary POMC mRNA levels by 54% (P < 0.01) and fetal serum ACTH levels to undetectable values (P < 0.05). The decline in ACTH was associated with decreases in fetal adrenal weight (P < 0.001), cortical cell size (P < 0.05), appearance of apoptosis and cellular disorganization, and a loss of immunocytochemically demonstrable definitive zone-specific delta5-3beta-hydroxysteroid dehydrogenase expression. The concomitant administration of ACTH and betamethasone restored these aspects of adrenal integrity to normal. Moreover, there was approximately a 95% decrease (P < 0.01) in fetal adrenal expression of ACTH receptor, P-450 cholesterol side-chain cleavage, and P-450 17alpha-hydroxylase 17/20-lyase mRNA levels after betamethasone administration. We conclude that fetal pituitary ACTH is necessary for the growth and development of fetal and definitive cortical zones and the marked coordinated increase in ACTH receptor and maintenance of P-450 cholesterol side-chain cleavage/P-450 17alpha-hydroxylase 17/20-lyase expression in the baboon fetal adrenal gland during the first half of gestation.