Expression and localization of macrophage elastase (matrix metalloproteinase-12) in abdominal aortic aneurysms

Elastolytic matrix metalloproteinases (MMPs) have been implicated in the pathogenesis of abdominal aortic aneurysms (AAA), a disorder characterized by chronic aortic wall inflammation and destruction of medial elastin. The purpose of this study was to determine if human macrophage elastase (HME; MMP-12) might participate in this disease. By reverse transcription-polymerase chain reaction, HME mRNA was consistently demonstrated in AAA and atherosclerotic occlusive disease (AOD) tissues (six of six), but in only one of six normal aortas. Immunoreactive proteins corresponding to proHME and two products of extracellular processing were present in seven of seven AAA tissue extracts. Total HME recovered from AAA tissue was sevenfold greater than normal aorta (P < 0.001), and the extracted enzyme exhibited activity in vitro. Production of HME was demonstrated in the media of AAA tissues by in situ hybridization and immunohistochemistry, but HME was not detected within the media of normal or AOD specimens. Importantly, immunoreactive HME was specifically localized to residual elastin fragments within the media of AAA tissue, particularly areas adjacent to nondilated normal aorta. In vitro, the fraction of MMP-12 sequestered by insoluble elastin was two- to fivefold greater than other elastases found in AAA tissue. Therefore, HME is prominently expressed by aneurysm-infiltrating macrophages within the degenerating aortic media of AAA, where it is also bound to residual elastic fiber fragments. Because elastin represents a critical component of aortic wall structure and a matrix substrate for metalloelastases, HME may have a direct and singular role in the pathogenesis of aortic aneurysms.

Production and localization of 92-kilodalton gelatinase in abdominal aortic aneurysms. An elastolytic metalloproteinase expressed by aneurysm-infiltrating macrophages

Abdominal aortic aneurysms (AAA) are characterized by disruption and degradation of the elastic media, yet the elastolytic proteinases involved and their cellular sources are undefined. We examined if 92-kD gelatinase, an elastolytic matrix metalloproteinase, participates in the pathobiology of AAA. Gelatin zymography of conditioned medium from normal, atheroocclusive disease (AOD), or AAA tissues in organ culture showed that all tissues produced 72-kD gelatinase. AOD and AAA cultures also secreted 92-kD gelatinase, but significantly more enzyme was released from AAA tissues. ELISA confirmed that AAA tissues released approximately 2-fold more 92-kD gelatinase than AOD tissue and approximately 10-fold more than normal aorta. Phorbol ester induced a 5.3-fold increase in 92-kD gelatinase secretion by normal aorta and AOD and an 11.5-fold increase by AAA. By immunohistochemistry, 92-kD gelatinase was not detected in normal aorta and was only occasionally seen within the neointimal lesions of AOD tissue. In all AAA specimens, however, 92-kD gelatinase was readily localized to numerous macrophages in the media and at the adventitial-medial junction. The expression of 92-kD gelatinase mRNA by aneurysm-infiltrating macrophages was confirmed by in situ hybridization. These results demonstrate that diseased aortic tissues secrete greater amounts of gelatinolytic activity than normal aorta primarily due to increased production of 92-kD gelatinase. In addition, the localization of 92-kD gelatinase to macrophages in the damaged wall of aneurysmal aortas suggests that chronic release of this elastolytic metalloproteinase contributes to extracellular matrix degradation in AAA.

Modulation of endocrine systems and food intake by green tea epigallocatechin gallate

Green tea polyphenols, especially the catechin, (-)-epigallocatechin gallate (EGCG), have been proposed as a cancer chemopreventative based on a variety of laboratory studies. For clear assessment of the possible physiological effects of green tea consumption, we injected pure green tea catechins ip into rats and studied their acute effects on endocrine systems. We found that EGCG, but not related catechins, significantly reduced food intake; body weight; blood levels of testosterone, estradiol, leptin, insulin, insulin-like growth factor I, LH, glucose, cholesterol, and triglyceride; as well as growth of the prostate, uterus, and ovary. Similar effects were observed in lean and obese male Zucker rats, suggesting that the effect of EGCG was independent of an intact leptin receptor. EGCG may interact specifically with a component of a leptin-independent appetite control pathway. Endocrine changes induced by parenteral administration of EGCG may relate to the observed growth inhibition and regression of human prostate and breast tumors in athymic mice treated with EGCG as well as play a role in the mechanism by which EGCG inhibits cancer initiation and promotion in various animal models of cancer.

Secretory proteins move through the endoplasmic reticulum membrane via an aqueous, gated pore

The environment of secretory proteins undergoing translocation across the ER membrane was determined by incorporating fluorescent probes into nascent chains during translation. Dyes were positioned at various locations across the entire bilayer and inside the ribosome, and in each case the probes were in an aqueous milieu, as shown both by their fluorescence lifetimes and by collisional quenching of their fluorescence by iodide ions introduced into the ER lumen. The nascent chain therefore occupies an aqueous pore that spans the entire membrane. Since the pore is sealed off from the cytoplasm, cotranslational translocation is effected topographically. This pore is not open to the lumen after targeting is completed; it opens only after the nascent chain length reaches about 70 residues.

Detection of clonal T-cell receptor gamma gene rearrangements in early mycosis fungoides/Sezary syndrome by polymerase chain reaction and denaturing gradient gel electrophoresis (PCR/DGGE)

We used a gene amplification strategy to analyze T-cell receptor (TCR) gene rearrangements in 185 specimens, including mycosis fungoides/Sezary syndrome (MF/SS), other cutaneous neoplasms, inflammatory dermatoses, reactive lymphoid tissues, and normal skin. Genomic DNA was extracted from lesional tissues and rearrangements of the TCR-gamma chain gene were amplified using the polymerase chain reaction (PCR) with primers specific for rearrangements involving V gamma 1-8 or V gamma 9 gene segments. The resulting PCR products were then separated according to their nucleotide sequence as well as size by denaturing gradient gel electrophoresis (DGGE). Dominant clonal TCR-gamma gene rearrangements were detected in 61 of 68 MF/SS cases by PCR/DGGE. This sensitivity of 90% compared to a sensitivity of only 59% when dominant clonality was sought in 17 of these same cases by Southern blot analysis of TCR-beta gene rearrangements. This difference in sensitivity was greatest in early, minimally infiltrated skin lesions. PCR/DGGE was also more sensitive than Southern blot analysis for detecting peripheral blood involvement in two cases of early MF. Among 12 additional specimens of suspected MF/SS, nine (75%) showed clonal TCR-gamma gene rearrangements by PCR/DGGE including six of eight cases with a previously confirmed diagnosis of MF/SS and three of four cases without prior known MF/SS. Among 105 non-MF/SS specimens, dominant TCR-gamma gene rearrangements were detected in only six cases (6%). Four were diagnosed as chronic dermatitis and two were diagnosed as cutaneous lymphoid hyperplasia. We conclude that the large majority of MF/SS cases, including patch phase disease, possess dominant clonal TCR-gamma gene rearrangements. PCR/DGGE is more sensitive than Southern blot analysis for detecting dominant clonality and staging disease in patients with a confirmed diagnosis of MF/SS. However, because PCR/DGGE is sensitive enough to detect dominant TCR-gamma gene rearrangements in a subset of patients with chronic dermatitis, it cannot be used as the sole criterion for establishing a diagnosis of T-cell lymphoma. As with other molecular biologic clonality assays, clinicopathologic correlation is essential. Nevertheless, the detection of dominant clonality in some cases of histologically nonspecific dermatitis allows the identification of a previously unrecognized subset of patients, i.e., those with "clonal dermatitis." It will be important to determine the long-term risk of MF/SS among these patients because our study indicated that MF/SS can sometimes present with lesions indistinguishable from clonal dermatitis.

Growth inhibition and regression of human prostate and breast tumors in athymic mice by tea epigallocatechin gallate

The human prostate cancer cell lines, PC-3 (androgen-insensitive) and LNCaP 104-R (androgen-repressed) were inoculated subcutaneously into nude mice to produce prostate tumors. Intraperitoneal injection of green tea (-)epigallocatechin-3-gallate but not structurally related catechins, such as (-)epicatechin-3-gallate, inhibited the growth and rapidly reduced the size of human prostate tumors in nude mice. (-)Epigallocatechin-3-gallate also rapidly inhibited the growth of tumor growth formed by the human mammary cancer cell line MCF-7 in nude mice. It is possible that there is a relationship between the high consumption of green tea and the low incidence of prostate and breast cancers in some Asian countries.

The effect of multidimensional exercises on balance, mobility, and fall risk in community-dwelling older adults

BACKGROUND AND PURPOSE

This prospective clinical investigation examined the effects of a multidimensional exercise program on balance, mobility, and risk for falls in community-dwelling older adults with a history of falling. Factors used to predict adherence and a successful response to exercise were identified.

SUBJECTS

A total of 105 community-dwelling older adults (> or = 65 years of age) with a history of two or more falls in the previous 6 months (no neurologic diagnosis) participated. They were classified into (1) a control group of fallers (n = 21), (2) a fully adherent exercise group (n = 52), and (3) a partially adherent exercise group (n = 32).

METHODS

Following evaluation, each patient received an individualized exercise program addressing the impairments and functional disabilities identified during the assessment. The control group received no intervention. Changes in performance on five clinical tests of balance and mobility and fall risk were compared among groups.

RESULTS

Both exercise groups scored better than the control group on all measures of balance and mobility. Although both exercise groups showed a reduction in fall risk compared with the control group, the greatest reduction was found in the fully adherent exercise group. Factors associated with successful response to exercise included degree of adherence to exercise program and pretest score on the Tinetti Mobility Assessment.

CONCLUSION AND DISCUSSION

Exercise can improve balance and mobility function and reduce the likelihood for falls among community-dwelling older adults with a history of falling. The amount of exercise needed to achieve these results, however, could not be determined from this study.

Doxycycline inhibition of aneurysmal degeneration in an elastase-induced rat model of abdominal aortic aneurysm: preservation of aortic elastin associated with suppressed production of 92 kD gelatinase

PURPOSE

Increased local production of matrix metalloproteinases (MMPs) is a potential mechanism underlying structural protein degradation in abdominal aortic aneurysms (AAA). With an elastase-induced rodent model of AAA, we determined whether pharmacologic treatment with an MMP-inhibiting tetracycline might limit the development of experimental AAA in vivo.

METHODS

Forty-eight Wistar rats underwent a 2-hour perfusion of the abdominal aorta with 50 U porcine pancreatic elastase and were then treated with either subcutaneous doxycycline (25 mg/day; n=24) or saline solution vehicle (n=24). Aortic diameter was measured before and after elastase perfusion was performed and before the rats were killed at 0, 2, 7, or 14 days, and AAAs were defined as an increase in aortic diameter to at least twice that before perfusion. At death the aortic tissues were either perfusion-fixed for histologic evaluation or extracted for substrate zymographic evaluation.

RESULTS

Aortic diameter was not different between groups at 0 or 2 days, but it was significantly less in animals treated with doxycycline at both 7 and 14 days (mean+/-SEM, p<0.01). After day 2 the incidence of AAA was reduced from 83% (10 of 12 rats treated with saline solution) to 8% (1 of 12 animals treated with doxycycline). By histologic assessment doxycycline prevented the structural deterioration of aortic elastin without decreasing the influx of inflammatory cells. Increased aortic wall production of 92 kD gelatinase observed in a saline solution-treated control group was markedly suppressed in animals treated with doxycycline.

CONCLUSIONS

Treatment with an MMP-inhibiting tetracycline inhibits the development of experimental AAA in vivo. This inhibition may be due to selective blockade of elastolytic MMP expression in infiltrating inflammatory cells. Additional experiments, however, are necessitated to fully delineate this process.

Both lumenal and cytosolic gating of the aqueous ER translocon pore are regulated from inside the ribosome during membrane protein integration

Portions of the nascent chain are exposed to the lumen, the cytosol, or neither at different stages during the cotranslational integration of a protein into the ER membrane, as shown by compartment-specific collisional quenching of fluorophores incorporated into the polypeptide. The opening or closing of each end of the aqueous translocon pore is tightly controlled and occurs in a sequence that does not compromise the membrane's permeability barrier. Surprisingly, these structural changes at the membrane are effected by the transmembrane segment in the nascent protein from inside the ribosome. Thus, the ribosome, not the translocon, first recognizes the transmembrane segment and triggers long-range structural changes at the translocon that may be involved in shifting its function from translocation to integration.

Ubiquitous receptor: a receptor that modulates gene activation by retinoic acid and thyroid hormone receptors

The cDNA for a member of the nuclear receptor family was cloned and named ubiquitous receptor (UR), since UR protein and mRNA are detected in many cell types. Rat UR/human retinoid X receptor alpha (hRXR alpha) heterodimers bound preferentially to double-stranded oligonucleotide direct repeats having the consensus half-site sequence AGGTCA and 4-nt spacing (DR-4). Coexpression of UR in COS-1 cells inhibited the stimulation of chloramphenicol acetyltransferase (CAT) reporter gene expression by hRXR alpha and human retinoic acid receptor alpha in the presence of all-trans-retinoic acid when DR-4 (but not DR-5) was present upstream of the promoter of a CAT reporter gene (DR-4-CAT). UR expression also inhibited the activation of a DR-4-CAT reporter gene by hRXR alpha and 9-cis-retinoic acid or by thyroid hormone receptor beta in the presence of thyroid hormone. However, in the absence of 9-cis-retinoic acid, UR in combination with hRXR alpha stimulation DR-4-CAT expression. Coexpression of thyroid hormone receptor markedly reduced this stimulation in the absence of thyroid hormone. UR may play an important role in normal growth and differentiation by modulating gene activation in retinoic acid and thyroid hormone signaling pathways.

Dominant local binary patterns for texture classification

This paper proposes a novel approach to extract image features for texture classification. The proposed features are robust to image rotation, less sensitive to histogram equalization and noise. It comprises of two sets of features: dominant local binary patterns (DLBP) in a texture image and the supplementary features extracted by using the circularly symmetric Gabor filter responses. The dominant local binary pattern method makes use of the most frequently occurred patterns to capture descriptive textural information, while the Gabor-based features aim at supplying additional global textural information to the DLBP features. Through experiments, the proposed approach has been intensively evaluated by applying a large number of classification tests to histogram-equalized, randomly rotated and noise corrupted images in Outex, Brodatz, Meastex, and CUReT texture image databases. Our method has also been compared with six published texture features in the experiments. It is experimentally demonstrated that the proposed method achieves the highest classification accuracy in various texture databases and image conditions.

Pharmacologic suppression of experimental abdominal aortic aneurysms: acomparison of doxycycline and four chemically modified tetracyclines

BACKGROUND

Matrix metalloproteinases (MMPs) likely contribute to the degradation of medial elastin in abdominal aortic aneurysms (AAAs), and tetracycline antibiotics exhibit MMP-inhibiting properties. The purpose of this study was to compare the effects of doxycycline and several non-antibiotic chemically modified tetracyclines (CMTs) in a rat model of elastase-induced AAA.

METHODS

Fifty-two male Wistar rats underwent intraluminal perfusion of the abdominal aorta with porcine pancreatic elastase. The rats then were treated for 7 days with subcutaneous injections of saline solution, different doses of doxycycline, or 1 of 4 different CMTs. The aortic diameters were measured with microcalipers, and the fixed tissues were examined by means of light microscopy. Gelatin zymography was used to assess the MMP activity in the aortic tissue extracts.

RESULTS

The mean aortic diameter in the control group increased by 126% +/- 14% on day 7 (from 1.57 +/- 0.04 mm to 3.54 +/- 0.27 mm; P <.05), and 5 of 6 animals (83%) had AAAs. Doxycycline appeared to inhibit aortic dilatation in a dose-dependent manner, and AAAs did not develop in any animals. Half-maximal effects were observed at a dose of approximately 6 mg/kg/day, and maximal effects were noted at greater than 30 mg/kg/day. No AAAs were observed in the animals that were treated with CMTs at 15 mg/kg/day. Each of the following CMTs exhibited an efficacy that was similar to that of doxycycline (percent inhibition of aortic dilatation vs control; all P <.05): CMT-3 (47.6%), CMT-4 (38.9%), CMT-7 (47.6%), CMT-8 (54.0%), and doxycycline (51.6%). Tissues from saline solution-treated controls exhibited a transmural inflammatory response and marked destruction of the medial elastic lamellae. Tetracycline derivatives limited the disruption of medial elastin without appearing to alter either the inflammatory response or the rat aortic wall production of metallogelatinases.

CONCLUSION

Tetracycline derivatives suppress the development of AAAs after elastase-induced aortic injury in the rat. The aneurysm-suppressing effects of doxycycline appear to be dose-dependent and distinct from its antibiotic activities, and they coincide with the structural preservation of medial elastin fibers. Further studies are needed to explore the potential of MMP-inhibiting tetracyclines as a novel pharmacologic strategy for the suppression of aortic aneurysms.

Progression of LNCaP prostate tumor cells during androgen deprivation: hormone-independent growth, repression of proliferation by androgen, and role for p27Kip1 in androgen-induced cell cycle arrest

The molecular mechanism of androgen-independent growth of prostate cancer after androgen ablation was explored in LNCaP cells. An androgen-dependent clonal subline of the LNCaP human prostate carcinoma cell line, LNCaP 104-S, progressed to a slow growing stage (104-R1) and then to a faster growing stage (104-R2) during more than 2 yr of continuous culture in the absence of androgen. Androgen-induced proliferation of 104-S cells is inhibited by the antiandrogen Casodex, while proliferation of 104-R1 and 104-R2 cells is unaffected by Casodex. This indicates that proliferation of 104-R1 and 104-R2 cells is not supported by low levels of androgen in the culture medium. Compared with LNCaP 104-S cells, both 104-R1 and 104-R2 cells express higher basal levels of androgen receptor (AR), and proliferation of these two cell lines is paradoxically repressed by androgen. After continuous passage in androgen-containing medium, 104-R1 cells reverted back to an androgen-dependent phenotype. The mechanism of androgenic repression of 104-R1 and 104-R2 sublines was further evaluated by examining the role of critical regulatory factors involved in the control of cell cycle progression. At concentrations that repressed growth, androgen transiently induced the expression of the cyclin-dependent kinase (cdk) inhibitor p21waf1/cip1 in 104-R1 cells, while expression of the cdk inhibitor p27Kip1 was persistently induced by androgen in both 104-R1 and 104-R2 cells. Induced expression of murine p27Kip1 in 104-R2 cells resulted in G1 arrest. Specific immunoprecipitates of Cdk2 but not Cdk4 from androgen-treated 104-R1 cells contained both p21waf1/cip1 and p27Kip1. This observation was confirmed by in vitro assay of histone H1 and Rb (retinoblastoma protein) phosphorylation by the proteins associated with the immune complex. Furthermore, inhibition of Cdk2 activity correlated with the accumulation of p27Kip1 and not p21waf1/cip1. From these results we conclude that androgenic repression of LNCaP 104-R1 and 104-R2 cell proliferation is due to the induction of p27Kip1, which in turn inhibits Cdk2, a factor critical for cell cycle progression and proliferation.

Human prostate tumor growth in athymic mice: inhibition by androgens and stimulation by finasteride

When the human prostate cancer cell line, LNCaP 104-S, the growth of which is stimulated by physiological levels of androgen, is cultured in androgen-depleted medium for > 100 passages, the cells, now called LNCaP 104-R2, are proliferatively repressed by low concentrations of androgens. LNCaP 104-R2 cells formed tumors in castrated male athymic nude mice. Testosterone propionate (TP) treatment prevented LNCaP 104-R2 tumor growth and caused regression of established tumors in these mice. Such a tumor-suppressive effect was not observed with tumors derived from LNCaP 104-S cells or androgen receptor-negative human prostate cancer PC-3 cells. 5 alpha-Dihydrotestosterone, but not 5 beta-dihydrotestosterone, 17 beta-estradiol, or medroxyprogesterone acetate, also inhibited LNCaP 104-R2 tumor growth. Removal of TP or implantation of finasteride, a 5 alpha-reductase inhibitor, in nude mice bearing TP implants resulted in the regrowth of LNCaP 104-R2 tumors. Within 1 week after TP implantation, LNCaP 104-R2 tumors exhibited massive necrosis with severe hemorrhage. Three weeks later, these tumors showed fibrosis with infiltration of chronic inflammatory cells and scattered carcinoma cells exhibiting degeneration. TP treatment of mice with LNCaP 104-R2 tumors reduced tumor androgen receptor and c-myc mRNA levels but increased prostate-specific antigen in serum- and prostate-specific antigen mRNA in tumors. Although androgen ablation has been the standard treatment for metastatic prostate cancer for > 50 years, our study shows that androgen supplementation therapy may be beneficial for treatment of certain types of human prostate cancer and that the use of 5 alpha-reductase inhibitors, such as finasteride or anti-androgens, in the general treatment of metastatic prostate cancer may require careful assessment.

Antibacterial dental composites with chlorhexidine and mesoporous silica

One of the leading causes for the failure of dental composite restorations is secondary caries. Effectively inhibiting cariogenic biofilms and reducing secondary caries could extend the service life of composite restorations. Dental composites releasing antibacterial agents such as chlorhexidine (CHX) have shown biofilm-inhibitory efficacy, but they usually have poor physical and mechanical properties. Herein, we present a study of a new method to encapsulate and release CHX from dental composite using mesoporous silica nanoparticles (MSNs). SBA-15 MSNs were synthesized according to a reported procedure. CHX (62.9 wt%) was encapsulated into dried MSN from 0.3 M CHX ethanol solution. The dental composites containing 0% (control), 3%, 5%, and 6.3% CHX or the same amounts of CHX entrapped in MSN (denoted as CHX@MSN) were fabricated with methacrylate monomers and silanized glass fillers (CHX or CHX@MSN + glass filler particle = 70 wt%). The monomer mixture consisted of bisphenol A glycidyl methacrylate (BisGMA), hexanediol dimethacrylate (HDDMA), ethoxylated bisphenol A dimethacrylate (EBPADMA), and urethane dimethacrylates (UEDMA) at a weight ratio of 40:30:20:10. The composites were tested for CHX release and recharge, flexural strength and modulus (at 24 hr and 1 mo), surface roughness, in vitro wear, and antibacterial activity against Streptococcus mutans and Lactobacillus casei (in both planktonic growth and biofilm formation). The results showed that the composites with CHX@MSN largely retained mechanical properties and smooth surfaces and showed controlled release of CHX over a long time. In contrast, the composites with directly mixed CHX showed reduced mechanical properties, rough surfaces, and burst release of CHX in a short time. The composites with CHX either directly mixed or in MSN showed strong inhibition to S. mutans and L. casei. This research has demonstrated the successful application of MSNs as a novel nanotechnology in dental materials to inhibit oral biofilm without sacrificing materials' mechanical properties and surface integrity.

Vascular smooth muscle cell apoptosis in abdominal aortic aneurysms

Apoptosis is a naturally occurring mechanism of cell death that plays an important role in both normal and pathological remodeling of the vessel wall. Abdominal aortic aneurysms (AAA) represent a unique and dramatic example of vessel wall remodeling characterized by degeneration of the elastic media. Although much attention has been focused on the proteolytic mechanisms that underlie elastin and collagen degradation in AAA, recent studies suggest that depletion of medial smooth muscle cells (SMC) makes an important contribution to this disease by eliminating a cell population capable of directing connective tissue repair. As described in this review, these investigations have revealed that SMC depletion in human aneurysm tissues is accompanied by biochemical, morphological and molecular changes consistent with SMC apoptosis. The exact mechanisms responsible for SMC apoptosis in AAA remain to be elucidated, but current evidence indicates that elevated cellular production of p53 and p21 participates in the process. These findings provide an important new starting point for further investigations on the cellular and molecular mechanisms underlying SMC depletion in AAA and how this process might trigger the accelerated progression of aneurysm disease.

Recovery trends over three years following pediatric traumatic brain injury

This cohort study investigated the magnitude of neurobehavioral, academic, and "real world" deficits over the course of 3 years in children with mild, moderate, and severe traumatic brain injury (TBI), and their individually matched controls. This series of analyses addresses the history of recovery, tracing changes in performance over time. Data on 72 case-control pairs (mild, n = 40; moderate, n = 17; severe, n = 15) were available for three testing times: 3 weeks, 1 year, and 3 years after the resolution of post-traumatic amnesia. The same standardized battery of tests was used at all testing times. The dependent variables in these analyses included individual test results, a variable summarizing results within each of 10 neurobehavioral domains, and an overall score across all domains. Three statistics were calculated for each variable: (1) the "grand" mean across the three testing times; (2) the slope (expressing the linear trend in performance); and (3) the change in slope over time (expressing the change in the rate of recovery). Use of the differences between case and control scores controlled for premorbid factors, maturation, and test-retest effects. Results indicate the chronicity of neurobehavioral deficits across all 3 years for moderately and severely injured children. They show a strong improvement rate during the first year, but a negligible rate of change during the following 2 years postinjury in most domains. All three of the time components--grand mean, slope, and change in slope--have significant Spearman correlations with severity ranging up to rho = -.5. Over time, the recovery rate slows down more for those with greater brain injury severity. The greatest slowing of recovery occurs in Performance IQ, adaptive problem solving, memory, and motor skills, as well as on a summary score of overall performance. Given this "plateauing" of recovery, achievement of parity with peers by the moderately and severely injured seems unlikely. Mildly injured children, however, exhibit negligible deficits or change in performance over time.

Suppression of experimental abdominal aortic aneurysms in the rat by treatment with angiotensin-converting enzyme inhibitors

PURPOSE

Pathologic remodeling of the extracellular matrix is a critical mechanism in the development and progression of abdominal aortic aneurysms (AAAs). Although angiotensin-converting enzyme (ACE) inhibitors are known to alter vascular wall remodeling in other conditions, their effects on AAAs are unknown. In this study we assessed the effect of ACE inhibitors in a rodent model of aneurysm development.

METHODS

Male Wistar rats underwent transient aortic perfusion with porcine pancreatic elastase, followed by treatment with one of three ACE inhibitors (captopril [CP], lisinopril [LP], or enalapril [EP]), an angiotensin (AT)1 receptor antagonist (losartan [LOS]), or water alone (9 rats in each group). Blood pressure and aortic diameter (AD) were measured before elastase perfusion and on day 14, with an AAA defined as an increase in AD (DeltaAD) of more than 100%. The structural features of the aortic wall were examined by means of light microscopy.

RESULTS

Aneurysmal dilatation consistently developed within 14 days of elastase perfusion in untreated rats, coinciding with the development of a transmural inflammatory response and destruction of the elastic media (mean DeltaAD, 223% +/- 28%). All three ACE inhibitors prevented AAA development (mean DeltaAD: CP, 67% +/- 4%; LP, 18% +/- 12%; and EP, 14% +/- 3%; each P <.05 vs controls). ACE inhibitors also attenuated the degradation of medial elastin without diminishing the inflammatory response. Surprisingly, the aneurysm-suppressing effects of ACE inhibitors were dissociated from their effects on systemic hemodynamics, and LOS had no significant effect on aneurysm development compared with untreated controls (mean DeltaAD, 186% +/- 19%).

CONCLUSION

Treatment with ACE inhibitors suppresses the development of elastase-induced AAAs in the rat. Although this is associated with the preservation of medial elastin, the mechanisms underlying these effects appear to be distinct from hemodynamic alterations alone or events mediated solely by AT1 receptors. Further studies are needed to elucidate how ACE inhibitors influence aortic wall matrix remodeling during aneurysmal degeneration.

Fatigue in an older population

OBJECTIVES

Fatigue is a common symptom that has not been studied well in the older populations. The purpose of this pilot study was to examine the epidemiology of fatigue symptoms in relation to demographic and medical characteristics of older patients in a long-term care setting.

DESIGN

A cross-sectional interviewer-assisted survey.

PARTICIPANTS/SETTING

A total of 199 ambulatory older residents of a single residential care facility.

MEASUREMENTS

Along with medical and demographic characteristics, the survey included mental status (Folstein), activities of daily living (Katz and Lawton), depression (Yesavage GDS), a 3-minute walk, a 7-item pain scale, and the modified Piper Fatigue Scale.

RESULTS

One-hundred ninety-nine (65%) of 308 potential subjects completed the study (mean age 88 years, 82% female). Of these 199 subjects, 195 (98%) reported some fatigue symptoms (median duration 44 weeks). Significant (P < .0005) relationships were found between fatigue and GDS (r = 0.57), 3-minute walk (r = -0.29), Lawton IADLs (r = 0.31), pain (r = 0.36), and number of medications (r = 0.26). No significant relationships were found between fatigue and age, sex, Folstein score, or number of medical diagnoses. Multivariate regression analysis identified GDS, pain, number of medications and 3-minute walk as significant predictors of fatigue intensity (multiple R = 0.68, r2 = 0.46, P < .02).

CONCLUSIONS

Fatigue is a symptom often found among older residents of a residential facility and has important implications for quality of life. Fatigue is poorly recognized and probably undertreated in older people.

Selective inhibition of steroid 5 alpha-reductase isozymes by tea epicatechin-3-gallate and epigallocatechin-3-gallate

Inhibitors of 5 alpha-reductase may be effective in the treatment of 5 alpha-dihydrotestosterone-dependent abnormalities, such as benign prostate hyperplasia, prostate cancer and certain skin diseases. The green tea catechins, (-)epigallocatechin-3-gallate and (-)epicatechin-3-gallate, but not (-)epicatechin and (-)epigallocatechin, are potent inhibitors of type 1 but not type 2 5 alpha-reductase. (-)Epigallocatechin-3-gallate also inhibits accessory sex gland growth in the rat. These results suggest that certain tea gallates can regulate androgen action in target organs.

Inhibition of steroid 5 alpha-reductase by specific aliphatic unsaturated fatty acids

Human or rat microsomal 5 alpha-reductase activity, as measured by enzymic conversion of testosterone into 5 alpha-dihydrotestosterone or by binding of a competitive inhibitor, [3H]17 beta-NN-diethulcarbamoyl-4-methyl-4-aza-5 alpha-androstan-3-one ([3H]4-MA) to the reductase, is inhibited by low concentrations (less than 10 microM) of certain polyunsaturated fatty acids. The relative inhibitory potencies of unsaturated fatty acids are, in decreasing order: gamma-linolenic acid greater than cis-4,7,10,13,16,19-docosahexaenoic acid = cis-6,9,12,15-octatetraenoic acid = arachidonic acid = alpha-linolenic acid greater than linoleic acid greater than palmitoleic acid greater than oleic acid greater than myristoleic acid. Other unsaturated fatty acids such as undecylenic acid, erucic acid and nervonic acid, are inactive. The methyl esters and alcohol analogues of these compounds, glycerols, phospholipids, saturated fatty acids, retinoids and carotenes were inactive even at 0.2 mM. The results of the binding assay and the enzymic assay correlated well except for elaidic acid and linolelaidic acid, the trans isomers of oleic acid and linoleic acid respectively, which were much less active than their cis isomers in the binding assay but were as potent in the enzymic assay. gamma-Linolenic acid had no effect on the activities of two other rat liver microsomal enzymes: NADH:menadione reductase and glucuronosyl transferase. gamma-Linolenic acid, the most potent inhibitor tested, decreased the Vmax. and increased Km values of substrates, NADPH and testosterone, and promoted dissociation of [3H]4-MA from the microsomal reductase. gamma-Linolenic acid, but not the corresponding saturated fatty acid (stearic acid), inhibited the 5 alpha-reductase activity, but not the 17 beta-dehydrogenase activity, of human prostate cancer cells in culture. These results suggest that unsaturated fatty acids may play an important role in regulating androgen action in target cells.