Preclinical and clinical investigation of histone deacetylase inhibitor valproic acid given orally in androgen independent prostate cancer

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Background: Considerable preclinical data suggests that histone deacetylase inhibitors (HDAIs) can cause differentiation and apoptosis of prostate cancer cell lines and inhibit prostate cancer xenografts in vivo. There is evidence that valproic acid (VPA) is a HDAI and can be administered safely to cancer patients intravenously (Atmaca et al J Clin Oncol 2004). Methods: In the current investigation, 6 cell lines of a variety of solid tumors including prostate cancers were treated with escalating concentrations of VPA (0.5, 1, 2 and 4 mM) over 24–144 hours. Cell growth inhibition was studied by a modified MTS assay. Simultaneously, patients with androgen independent prostate cancers were treated with dose escalations of oral VPA every week or as tolerated (10, 15, 20, 25 mg/kg). Weekly total and free serum VPA, PSA and serum testosterone levels were obtained. In addition, lymphocytes were collected for histone H3 acetylation. Results: VPA inhibited all solid tumor cell lines in a dose-dependent and time-dependent fashion. Optimal (>50% over control) inhibition of most cell lines required 2–4 mM exposure over at least 72–96 hours. Prostate and lung cancer lines were more sensitive to inhibition after VPA administration. A total of 5 patients (Median age 71, Range 48–78) were treated with VPA. Major adverse events included Gr 1 confusion (1 pt), Gr 1 fatigue (3 pts), Gr 1 Dizziness (2 patients) and Gr 1 nausea and vomiting (1 pt). When PSA levels were normalized for simultaneously drawn serum testosterone (Median 20, Range 16–281 ng/dl), all patients had transient drops in PSA. In 3 of 4 evaluable patients, normalized PSA increased after patients were discontinued from VPA because of side effects or co-morbid conditions. In 1 patient, normalized PSA declined after re-challenge with VPA. Conclusions: In this study, VPA has demonstrable activity in cell lines and in patients as measured by lowered PSA levels. Normalization of PSA to serum testosterone might be important to detect clinical effects of HDAIs. Updated clinical data and a correlation between PSA, serum levels of VPA and histone acetylation will be presented.

No significant financial relationships to disclose.

Brain MRI and proton MRS findings in infants and children with respiratory chain defects

OBJECTIVE

The aim of this study is to describe neuroimaging patterns in children with respiratory chain (RC) defects using magnetic resonance imaging (MRI) and proton magnetic resonance spectroscopy (MRS) and to assess their role in the diagnostic evaluation.

METHOD

Neuroimaging studies of 49 children (newborn to 15 years old) with biochemical evidence of RC defect were reviewed. Patients were divided in 3 groups ("definite" = 24, "probable" = 14, "possible" = 11) according to Modified Adult Criteria for the diagnosis of RC defect. Eighty-one MRI studies were reviewed for deep gray and white matter changes, degree of myelination, cerebral and cerebellar atrophy, and 67 proton MRS studies were assessed for the presence or absence of lactate elevation, as well as NAA/Cr ratio. The findings were compared among the 3 groups with chi-square test.

RESULTS

All patients with "pure" myopathy had normal imaging studies. In patients with CNS involvement, significant differences in the frequency of imaging abnormalities among groups were found for deep gray matter (43 %/8 %/0 %; p = 0.01) and for the presence of lactate elevation on proton MRS (81 %/31 %/0 %; p = 0.001).

CONCLUSION

Brain MRI and proton MRS abnormalities were observed only in association with clinical CNS involvement. Deep gray matter signal abnormalities on structural imaging and lactate elevation on proton MRS were more frequently observed in the "definite" group and represent neuroimaging markers for RC mitochondriopathy.

Accuracy of the funnel technique of thoracic pedicle screws insertion in scoliosis surgery--an evaluation by CT-scans

Pedicle screw system has increasingly been used for correction of thoracic scoliosis. It offers several biomechanical advantages over hook system as it controls all three-column of the spine with enhanced stability. Of many techniques of pedicle screw placement in the thoracic spine, the funnel technique has been used in Sarawak General Hospital since 2002. This prospective study aims to assess the accuracy of the placement of thoracic pedicle screws using the funnel technique in the corrective surgery of idiopathic scoliosis. A total of 88 thoracic pedicle screws were inserted into the T4 to T12 vertebrae of 11 patients. Post-operative CT-scan was performed to evaluate the position of the pedicle screw. Seventy six (86.4%) screws were noted to be totally within the pedicle. There was no screw with medial violation of the pedicle, 8 (9.1%) screws breeching the lateral wall of the pedicle and 4 (4.5%) screws with anterior and lateral penetration of the vertebral body. No clinical sequel with the mal-positioned screws was noted. In conclusion, the funnel technique enabled simple, accurate and reliable insertion of pedicle screw even in the scoliotic thoracic spine without the need of any imaging guidance. It is however imperative for the surgeon to have a thorough knowledge of the thoracic spine anatomy, and to be familiar with the technique to insert these screws diligently.

A murine model for the study of immune memory in response to pneumococcal conjugate vaccination

We developed a murine model for assessment of immunological memory and antibody-induced protection to nasopharyngeal (NP) challenges. BALB/c female mice (n = 10 mice per study parameter) were immunized with two priming doses of the licensed 7-valent pneumococcal (Pnc) conjugate vaccine and immune responses [antibody immunoglobulin G (IgG) levels, avidity and opsonophagocytic activity] were monitored for 26 weeks until IgG levels decreased to nearly baseline. A booster dose of either 2 microg conjugate or 5 microg polysaccharide vaccine was given at week 26. The ability of these two treatments to recall immune memory established by the conjugate vaccine was determined for types 4 and 14 for up to 63 days post-booster. The ability of challenge with pneumococcal type 14 to recall the immune response was also evaluated, as well as, the number of antibody secreting cells (ASC) specific to polysaccharide (Ps) 4, 6B, and 14. A higher dose of conjugate vaccine (2 microg) was necessary to elicit a significant increase in IgG levels after priming with one dose. Priming with lower doses (0.5 and 1.0 microg) only elicited modest increases in IgG levels. Recall of the immune response was found with either conjugate or Ps vaccines. NP challenge with type 14 at week 26 did not recall the immune response, although reduction in NP Pnc load was seen post-primary immunization at 5, 10 and 26 weeks. ASCs were detected in response to either conjugate or Ps booster doses. This model allows for the screening and determination of potential alternative vaccination regimens and the study of immunological markers of memory following Pnc vaccination.

Does the discharge ECG provide additional prognostic insight(s) in non-ST elevation ACS patients from that acquired on admission?

BACKGROUND

Although the prognostic value of admission ST changes in patients with non-ST elevation acute coronary syndrome (ACS) is established, the utility of the discharge ECG is unknown. Accordingly, using the PARAGON-B Troponin substudy, we assessed the prevalence of ST depression on both admission and discharge ECG, the likelihood of developing new Q-waves at discharge and the additional prognostic value of these changes.

METHODS AND RESULTS

Nine hundred and eighteen patients were studied; 542 patients (59%) had admission ST downward arrow > or =1mm and 376 patients (41%) did not and their 6-month mortality was 4.4 vs 0.8%, P=0.002, respectively. Of patients with ST downward arrow on admission, 320 (59%) normalized their ST segment at discharge. Of patients without ST downward arrow on admission, 35 (9.3%) developed new ST downward arrow at discharge. Patients with persistent ST downward arrow on discharge had a higher 6-month mortality (6.0 vs 0.9%), (re)MI (16.3 vs 7.4%), and death/(re)MI (20.0 vs 8.3%) than those who never had ST downward arrow (all P< or =0.002). Two hundred and fifty-six patients had Q-waves on admission whereas by discharge 320 had Q-waves. Patients with Q-waves on discharge vs those without had a higher mortality (4.8 vs 1.9%), (re)MI (13.8 vs 8.3%), and death/(re)MI (16.4 vs 9.6%) at 6 months (all P< or =0.021).

CONCLUSIONS

This study highlights that the dynamic ECG changes which occur between admission and discharge in non-ST elevation ACS patients allows further risk stratification in determining the likelihood of 6-month death and/or re(MI).

Affinity purification of diverse plant and human 14-3-3-binding partners

Many proteins that bind to a 14-3-3 column in competition with a 14-3-3-binding phosphopeptide have been purified from plant and mammalian cells and tissues. New 14-3-3 targets include enzymes of biosynthetic metabolism, vesicle trafficking, cell signalling and chromatin function. These findings indicate central regulatory roles for 14-3-3s in partitioning carbon among the pathways of sugar, amino acid, nucleotide and protein biosynthesis in plants. Our results also suggest that the current perception that 14-3-3s bind predominantly to signalling proteins in mammalian cells is incorrect, and has probably arisen because of the intensity of research on mammalian signalling and for technical reasons.

Facial trauma and ocular/orbital injury

BACKGROUND AND OBJECTIVES

Ocular injuries occur commonly in patients with facial trauma. Patients with significant eye injuries may present with grossly normal eyes and good visual acuity; however, subsequent ocular disorders may become apparent. The estimates of incidence vary considerably. Trauma is the second leading cause of blindness, and a review is, therefore, warranted.

METHODS AND MATERIALS

Several extensive studies are reviewed. Blunt and penetrating trauma are examined by their respective subdivisions. The initial assessment and ophthalmologic examination of patients with facial trauma are discussed, and the type of injury that may occur secondary to trauma is delineated. Management is reviewed and discussed, including a recently developed diagnostic scoring system. Three clinical cases illustrate the procedure.

RESULTS AND/OR CONCLUSIONS

The diagnosis of ocular injuries resulting from trauma is difficult. The recently introduced scoring system was found to improve the procedure. Based on this system, the authors have devised an algorithm to assist the clinician, with emphasis on visual acuity and the importance of visual examination.

11 Beta-hydroxysteroid dehydrogenase type 1 is induced in human monocytes upon differentiation to macrophages

11beta-hydroxysteroid dehydrogenases (11beta-HSD) perform prereceptor metabolism of glucocorticoids through interconversion of the active glucocorticoid, cortisol, with inactive cortisone. Although the immunosuppressive and anti-inflammatory activities of glucocorticoids are well documented, the expression of 11beta-HSD enzymes in immune cells is not well understood. Here we demonstrate that 11beta-HSD1, which converts cortisone to cortisol, is expressed only upon differentiation of human monocytes to macrophages. 11beta-HSD1 expression is concomitant with the emergence of peroxisome proliferator activating receptor gamma, which was used as a surrogate marker of monocyte differentiation. The type 2 enzyme, 11beta-HSD2, which converts cortisol to cortisone, was not detectable in either monocytes or cultured macrophages. Incubation of monocytes with IL-4 or IL-13 induced 11beta-HSD1 activity by up to 10-fold. IFN-gamma, a known functional antagonist of IL-4 and IL-13, suppressed the induction of 11beta-HSD1 by these cytokines. THP-1 cells, a human macrophage-like cell line, expressed 11beta-HSD1 and low levels of 11beta-HSD2. The expression of 11beta-HSD1 in these cells is up-regulated 4-fold by LPS. In summary, we have shown strong expression of 11beta-HSD1 in cultured human macrophages and THP-1 cells. The presence of the enzyme in these cells suggests that it may play a role in regulating the immune function of these cells.

Statins suppress THP-1 cell migration and secretion of matrix metalloproteinase 9 by inhibiting geranylgeranylation

Macrophages secrete matrix metalloproteinase 9 (MMP-9), an enzyme that weakens the fibrous cap of atherosclerotic plaques, predisposing them to plaque rupture and subsequent ischemic events. Recent work indicates that statins strongly reduce the possibility of heart attack. Furthermore, these compounds appear to exert beneficial effects not only by lowering plasma low-density-lipoprotein cholesterol but also by directly affecting the artery wall. To evaluate whether statins influence the proinflammatory responses of monocytic cells, we studied their effects on the chemotactic migration and MMP-9 secretion of human monocytic cell line THP-1. Simvastatin dose dependently inhibited THP-1 cell migration mediated by monocyte chemoattractant protein 1, with a 50% inhibitory concentration of about 50 nM. It also inhibited bacterial lipopolysaccharide-stimulated secretion of MMP-9. The effects of simvastatin were completely reversed by mevalonate and its derivatives, farnesylpyrophosphate and geranylgeranyl pyrophosphate, but not by ubiquinone. Additional studies revealed similar but more profound inhibitory effects with L-839,867, a specific inhibitor of geranylgeranyl transferase. However, alpha-hydroxyfarnesyl phosphonic acid, an inhibitor of farnesyl transferase, had no effect. C3 exoenzyme, a specific inhibitor of the prenylated small signaling Rho proteins, mimicked the inhibitory effects of simvastatin and L-839,867. These data supported the role of geranylgeranylation in the migration and MMP-9 secretion of monocytes.

Body-image attitudes and psychosocial functioning in Euro-American and Asian-American college women

Euro-American (n = 94) and Asian-American (n = 72) college women were compared on multiple dimensions of body image, including global body satisfaction, preoccupation with appearance, satisfaction with individual body parts or features, and weight concern, and psychosocial functioning, including self-esteem, public self-consciousness, social anxiety, and public body consciousness. Both groups reported similar scores on these variables and showed similar patterns of correlations between body-image and psychosocial variables. Despite similar global body satisfaction, there were group differences in satisfaction with individual body parts or features, with Asian-American women reporting lower satisfaction with six parts or features and higher satisfaction with one feature. Stepwise multiple regression analyses predicting global body satisfaction from individual body parts or features suggested that both the specific body parts or features most salient to global body satisfaction and the relative influence of these parts or features varied as a function of ethnicity. Implications of these findings for research and practice are discussed.

Induction of 11beta-hydroxysteroid dehydrogenase type 1 but not -2 in human aortic smooth muscle cells by inflammatory stimuli

The 11beta-hydroxysteroid dehydrogenase (11beta-HSD) enzymes catalyze the interconversion of active glucocorticoids (GC) with their inert metabolites, thereby regulating the functional activity of GC. While 11beta-HSD type 1 (11beta-HSD1) activates GC from their 11-keto metabolites, 11beta-HSD type 2 (11beta-HSD2) inactivates GC. Here we report that both of these enzymes are expressed in human aortic smooth muscle cells (SMC), and that 11beta-HSD1 is more abundant and is differentially regulated relative to 11beta-HSD2. Stimulation of SMC with IL-1beta or TNFalpha led to a time- and dose-dependent increase of mRNA levels for 11beta-HSD1, while 11beta-HSD2 mRNA levels decreased. Parallel enzyme activity studies showed increased conversion of 3H-cortisone to 3H-cortisol but not 3H-cortisol to 3H-cortisone, demonstrating 11beta-HSD1 in SMC acts primarily as a reductase. A similar increase of 11beta-HSD1 mRNA expression was also found in human bronchial SMC upon stimulation, indicating the regulatory effect is not limited to vascular smooth muscle. Additional parallel studies revealed a similar pattern of induction for 11beta-HSD1 and monocyte chemoattractant protein-1, a well-defined proinflammatory molecule. These data suggest 11beta-HSD1 may play an important role in regulating inflammatory responses in the artery wall and lung.

Lipids, apoprotein B, and associated coronary risk factors in urban and rural older Mexican populations

The objective of this comparative cross-sectional study was to determine the prevalence of dyslipidemias and examine its association with food intake and metabolic variables in urban and rural elder Mexican populations. Three different communities (urban areas of medium and low income and a rural area) were studied. A total of 344 subjects aged 60 years and older and 273 aged 35 to 59 years were included. The evaluated parameters were personal medical data, 24-hour diet recall, and fasting plasma lipids, insulin, and glucose levels. Older subjects, especially men, living in the rural area had lower cholesterol levels (5.02 +/- 0.97 v 5.6 +/- 1.07 mmol/L; P <.05) and insulin levels (12 +/- 10 v 42 +/- 68 mU/mL) and higher high-density lipoprotein cholesterol concentrations (1.31 +/- 0.36 v 1.07 +/-0.28 mmol/L) than the elders from the urban medium-income group. Possible explanations for these differences are found in the dietary habits of the groups. Rural elders had higher amounts of fiber (20 +/- 11 v 10 +/- 6 g/d) and carbohydrate (70% +/- 0.08% v 52% +/- 0.11% of calories) and lower fat (18% +/- 0.07% v 33% +/- 0.1% of calories) in their diets. In the urban groups, low-density lipoprotein hypercholesterolemia was present in 17.8% of adult and 39.1% of elderly women (P =.00001). In conclusion, environmental factors still play a prominent role in the pathophysiology of the dyslipidemias in the elderly.

Irreversible brain creatine deficiency with elevated serum and urine creatine: a creatine transporter defect?

Recent reports highlight the utility of in vivo magnetic resonance spectroscopy (MRS) techniques to recognize creatine deficiency syndromes affecting the central nervous system (CNS). Reported cases demonstrate partial reversibility of neurologic symptoms upon restoration of CNS creatine levels with the administration of oral creatine. We describe a patient with a brain creatine deficiency syndrome detected by proton MRS that differs from published reports. Metabolic screening revealed elevated creatine in the serum and urine, with normal levels of guanidino acetic acid. Unlike the case with other reported creatine deficiency syndromes, treatment with oral creatine monohydrate demonstrated no observable increase in brain creatine with proton MRS and no improvement in clinical symptoms. In this study, we report a novel brain creatine deficiency syndrome most likely representing a creatine transporter defect.

Prevalence and penetrance of germline BRCA1 and BRCA2 mutations in a population series of 649 women with ovarian cancer

A population-based series of 649 unselected incident cases of ovarian cancer diagnosed in Ontario, Canada, during 1995-96 was screened for germline mutations in BRCA1 and BRCA2. We specifically tested for 11 of the most commonly reported mutations in the two genes. Then, cases were assessed with the protein-truncation test (PTT) for exon 11 of BRCA1, with denaturing gradient gel electrophoresis for the remainder of BRCA1, and with PTT for exons 10 and 11 of BRCA2. No mutations were found in all 134 women with tumors of borderline histology. Among the 515 women with invasive cancers, we identified 60 mutations, 39 in BRCA1 and 21 in BRCA2. The total mutation frequency among women with invasive cancers, 11.7% (95% confidence interval [95%CI] 9.2%-14.8%), is higher than previous estimates. Hereditary ovarian cancers diagnosed at age <50 years were mostly (83%) due to BRCA1, whereas the majority (60%) of those diagnosed at age >60 years were due to BRCA2. Mutations were found in 19% of women reporting first-degree relatives with breast or ovarian cancer and in 6.5% of women with no affected first-degree relatives. Risks of ovarian, breast, and stomach cancers and leukemias/lymphomas were increased nine-, five-, six- and threefold, respectively, among first-degree relatives of cases carrying BRCA1 mutations, compared with relatives of noncarriers, and risk of colorectal cancer was increased threefold for relatives of cases carrying BRCA2 mutations. For carriers of BRCA1 mutations, the estimated penetrance by age 80 years was 36% for ovarian cancer and 68% for breast cancer. In breast-cancer risk for first-degree relatives, there was a strong trend according to mutation location along the coding sequence of BRCA1, with little evidence of increased risk for mutations in the 5' fifth, but 8.8-fold increased risk for mutations in the 3' fifth (95%CI 3.6-22.0), corresponding to a carrier penetrance of essentially 100%. Ovarian, colorectal, stomach, pancreatic, and prostate cancer occurred among first-degree relatives of carriers of BRCA2 mutations only when mutations were in the ovarian cancer-cluster region (OCCR) of exon 11, whereas an excess of breast cancer was seen when mutations were outside the OCCR. For cancers of all sites combined, the estimated penetrance of BRCA2 mutations was greater for males than for females, 53% versus 38%. Past studies may have underestimated the contribution of BRCA2 to ovarian cancer, because mutations in this gene cause predominantly late-onset cancer, and previous work has focused more on early-onset disease. If confirmed in future studies, the trend in breast-cancer penetrance, according to mutation location along the BRCA1 coding sequence, may have significant impact on treatment decisions for carriers of BRCA1-mutations. As well, BRCA2 mutations may prove to be a greater cause of cancer in male carriers than previously has been thought.

TBX5 transcription factor regulates cell proliferation during cardiogenesis

Mutations in human TBX5, a member of the T-box transcription factor gene family, cause congenital cardiac septation defects and isomerism in autosomal dominant Holt-Oram syndrome. To determine the cellular function of TBX5 in cardiogenesis, we overexpressed wild-type and mutant human TBX5 isoforms in vitro and in vivo. TBX5 inhibited cell proliferation of D17 canine osteosarcoma cells and MEQC quail cardiomyocyte-like cells in vitro. Mutagenesis of the 5' end of the T-box but not the 3' end of the T-box abolished this effect. Overexpression of TBX5 in embryonic chick hearts showed that TBX5 inhibits myocardial growth and trabeculation. TBX5 effects in vivo were abolished by Gly80Arg missense mutation of the 5' end of the T-box. PCNA analysis in transgenic chick hearts revealed that TBX5 overexpression does suppress embryonic cardiomyocyte proliferation in vivo. Inhibitory effects of TBX5 on cardiomyocyte proliferation include a noncell autonomous process in vitro and in vivo. TBX5 inhibited proliferation of both nontransgenic cells cocultured with transgenic cells in vitro and nontransgenic cardiomyocytes in transgenic chick hearts with mosaic expression of TBX5 in vivo. Immunohistochemical studies of human embryonic tissues, including hearts, also demonstrated that TBX5 expression is inversely related to cellular proliferation. We propose that TBX5 can act as a cellular arrest signal during vertebrate cardiogenesis and thereby participate in modulation of cardiac growth and development.

Production of matrix metalloproteinase-9 in CaCO-2 cells in response to inflammatory stimuli

Matrix metalloproteinase-9 (MMP-9) may play an important role in the development of inflammatory bowel disease (IBD). However, the cellular source of MMP-9 in the inflamed mucosa of IBD remains unclear. Here we report that MMP-9 mRNA is expressed in CaCO-2 cells, an intestinal epithelial cell line, and that its expression is upregulated by inflammatory stimuli. Stimulation of CaCO-2 cells with interleukin-1beta (IL-1beta) or tumor necrosis factor-alpha (TNF-alpha) led to a dose-dependent increase in expression and secretion of MMP-9. In contrast, bacterial lipopolysaccharide (LPS) failed to induce expression or secretion of MMP-9, suggesting that an inflammatory reaction leading to cytokine release is a necessary step for the induction of MMP-9 release in intestinal epithelial cells. Additional studies show that induction of MMP-9 mRNA peaked at 16 h of IL-1beta stimulation, whereas expression of monocyte chemoattractant protein-1 (MCP-1) and IL-8 both peaked at 3 h of stimulation. Treatment of CaCO-2 cells with rosiglitazone, a peroxisome proliferator-activated receptor-gamma (PPAR-gamma) agonist, significantly reduced secretion of MMP-9, indicating that agents that activate PPAR-gamma may have therapeutic use in patients with IBD.

Primary central nervous system lymphoma in childhood presenting as progressive panhypopituitarism

We report a 15-year-old boy who had isolated central diabetes insipidus initially diagnosed at age 11 years. A brain magnetic resonance imaging (MRI) was normal at the time. At age 12 years, growth hormone (GH) testing was performed because of a decline in linear growth rate and demonstrated GH deficiency. After a repeat normal brain MRI, GH therapy was begun. Three years later, hormonal testing revealed prepubertal gonadotropins and low testosterone levels, free thyroxine index, and morning cortisol levels. Repeat brain MRI demonstrated a 9-mm enhancing lesion in the region of the pituitary stalk. The pathologic diagnosis was that of a high-grade malignant B-cell lymphoma, suggestive of Burkitt Lymphoma. Growth hormone therapy has not been associated with an increased incidence of lymphoma. This report underscores the need for vigilance in follow-up brain imaging and hormonal evaluation in children with diabetes insipidus, especially those with evolving anterior hormone deficiencies.

Clinical and radiological amelioration of refractory peripheral spondyloarthritis by pulse intravenous pamidronate therapy

OBJECTIVE

To examine the potential therapeutic properties of an aminobisphosphonate, pamidronate, using clinical and laboratory outcome variables together with dynamic magnetic resonance imaging (MRI) and gadolinium augmentation in patients with spondyloarthropathy (SpA) refractory to nonsteroidal antiinflammatory drugs (NSAID).

METHODS

We studied 9 patients (7 male, 2 female) of mean age 27.9 years (range 19-38) and mean disease duration of 5.5 years (range 0.5-20). Five had ankylosing spondylitis (AS), 3 had undifferentiated SpA, and one had reactive arthritis. Seven were HLA-B27 positive. Two had inflammatory bowel disease. Pamidronate (60 mg) was given intravenously on Days 1, 2, 14, 28, and 56, over 4 h in 500 ml of 5% dextrose. Clinical outcome assessments included the BASDAI (disease activity), BASFI (function), BASGI (global well being) composite visual analog instruments, and swollen and tender joint count. Laboratory variables included the erthrocyte sedimentation rate (ESR) and C-reactive protein (CRP). Dynamic MRI with gadolinium augmentation of synovium and bone was performed at baseline and at Day 84 in the first 6 patients enrolled in the study.

RESULTS

All patients completed the study and there was a significant improvement in all clinical and laboratory variables assessed. Mean swollen and tender joint count decreased by 93.8% (p = 0.017) and 98.2% (p = 0.012), respectively, and complete clinical resolution of synovitis was noted in 5 patients. BASDAI decreased by 44.2% (p = 0.028), BASFI by 47.3% (p = 0.015), and BASGI by 42.2% (p = 0.011). ESR and CRP declined by 49.4% (p = 0.012) and 66.9% (p = 0.008), respectively. Acute lymphopenia accompanied by elevated CRP levels was noted in 8 patients in the 48 h after first pamidronate infusion. Maximal rate and magnitude of enhanced MRI signal after gadolinium augmentation decreased after pamidronate therapy, especially in the bone marrow.

CONCLUSION

Preliminary data from uncontrolled studies support the efficacy of pamidronate therapy for NSAID refractory SpA and warrant further evaluation in controlled trials.

Alleles of the estrogen receptor alpha-gene and an estrogen receptor cotranscriptional activator gene, amplified in breast cancer-1 (AIB1), are associated with quantitative calcaneal ultrasound

Quantitative bone ultrasound (QUS) has a significant heritable component. Because estrogen is required for attainment of peak bone mass, we studied alleles of two genes, estrogen receptor alpha (ER1) and amplified in breast cancer-1 (AIB1), for their association with QUS. In a volunteer sample of 663 white women aged 18-35 years, bone ultrasound attenuation (BUA), speed of sound (SOS), and heel stiffness index (SI), the latter consisting of the component measures of BUA and SOS, were measured at the right calcaneus by QUS. Subjects were genotyped for the ER1 polymorphisms Xba I and Pvu II and for the AIB1 polyglutamine tract polymorphism. In a multiple regression analysis, ER1 genotype was an independent predictor of QUS-SI (p = 0.03). Because AIB1 and ER1 enhance gene expression in a coordinate manner, we also searched for interactions. A gene-by-gene interaction effect was seen for QUS-SI (p = 0.009), QUS-BUA (p = 0.03), and QUS-SOS (p = 0.004). These remained significant after the inclusion of clinically relevant variables into the final regression model. Overall, these clinical and genetic factors accounted for up to 16% of the variance in peak QUS; the genetic markers alone accounted for 4-7%. This is the first demonstration of specific genetic effects on calcaneal QUS encoded by alleles of genes directly involved in mediating estrogen effects on bone.

Validation of a blind transpyloric feeding tube placement technique in pediatric intensive care: rapid, simple, and highly successful

OBJECTIVE

Nasogastric feeding in intensive care is poorly tolerated as a result of gastroparesis. Transpyloric (TP) feeding has been limited by difficulty in tube placement. This study was to independently validate the success rate of a previously published bedside TP feeding tube (FT) placement technique.

DESIGN

Prospective interventional study.

SETTING

Tertiary pediatric intensive care unit (PICU) in a university hospital.

PATIENTS

Children whose intensivist requested TP feeding, and who were without known fundoplication, pharyngeal trauma, or gastric ulceration.

INTERVENTIONS

After informed consent, an unweighted polyurethane feeding tube with a flexible wire stylet was inserted using a standard technique with metoclopramide, right lateral position, and air insufflation during advancement until <2 mL air could be aspirated after insufflation of 5-10 mL air. The tubes were inserted by one of the authors, whose training was only to observe one insertion, then perform one insertion with supervision.

MEASUREMENTS AND MAIN RESULTS

Patient demographics, procedural data, and success rate based on radiography were prospectively recorded. There were 71 insertions on 38 patients from February 1999 to October 1999. Patients were aged 56 +/- 69.8 months, weighed 17.8 +/- 18 kg, 69% were ventilated, and 56% received procedural sedation. Success rate for TP-FT placement was 63/71 insertions (88.7%) in an average of 7.43 +/- 6.85 mins (median, 5 mins; range, <1-45 mins); of 38 patients, 36 had a successful TP- FT (95%). Insertion was well tolerated. Of the successful TP-FTs, on day 1 (n = 63) the FT was in distal duodenum or jejunum in 51% and by days 3-5 (n = 51), this increased to 75%.

CONCLUSIONS

Bedside placement of a TP-FT with this technique is simple, rapid, well tolerated, and highly successful with little training. Immediate radiograph to confirm TP placement may not always be necessary. In our experience, this technique has obviated the need to search for another method to achieve a transpyloric feeding tube.

Pathogenesis of Cryptococcus neoformans is associated with quantitative differences in multiple virulence factors

Two isolates of Cryptococcus neoformans were previously described as being highly divergent in their level of capsule synthesis in vivo and in their virulence for mice. The highly virulent isolate (NU-2) produced more capsule than a weakly virulent isolate (184A) in vitro under tissue culture conditions and in vivo. This investigation was done to determine if there were differences between the two isolates in other factors that might also contribute to virulence. Growth rate was not a factor as NU-2 grew more slowly than 184A. Based on PCR fingerprinting the two isolates were genetically different providing an opportunity to examine differences in multiple virulence traits. Quantitative analysis revealed that NU-2 expressed significantly more melanin and mannitol than did 184A. Although the isolates expressed the same capsular chemotype, NU-2 produced an additional structure reporter group (SRG) under tissue culture conditions that was not present when grown in glucose salts/urea/basal medium (GSU). Capsular polysaccharide SRGs of 184A were unaffected by shifting the growth conditions from GSU to tissue culture conditions. Our results suggest that pathogenesis of a C. neoformans strain is dictated by the quantitative expression of the strain's combined virulence traits. Regulators of the expression of these genes may be playing key roles in virulence.

The economic burden of congestive heart failure in a managed care population

OBJECTIVE

To examine the economic burden of and treatment patterns for congestive heart failure (CHF) in a managed care population.

STUDY DESIGN

Retrospective review of medical and pharmacy claims.

PATIENTS AND METHODS

We reviewed integrated medical and pharmacy claims data from 6 independent-practice-association model health maintenance organizations to identify patients diagnosed with CHF. Of the approximately 1.4 million people enrolled in these managed care plans during the study period (January through December 1994), a total of 2777 patients (mean age, 56.9 years) met the study criteria, which included diagnostic codes for CHF and claims eligibility of at least 1 year. We reviewed the charges incurred by patients diagnosed with CHF for the 6 months after the initial CHF medical claim. We also examined the treatment received by each of these patients.

RESULTS

During the study period, 378 of the 2777 patients with CHF (14%) were admitted to the hospital at a cost of almost $3 million (an average of $7863 per hospitalized patient). Seventy-eight percent of the study population received prescription drugs, at an average per-patient cost of $942. The most commonly prescribed drug class was angiotensin-converting enzyme inhibitors, prescribed for 38% of patients. Calcium channel blockers were prescribed for 33% of patients, but beta-blockers were prescribed for only 18% of patients. Hospitalization accounted for 54% of the total cost for CHF treatment, with prescription drugs accounting for 38%.

CONCLUSION

Congestive heart failure represents a significant financial burden within a non-elderly managed care population. Improved management of the condition is needed to reduce the morbidity and mortality, as well as the costs of treatment, associated with CHF. Considerable data indicate that drugs such as beta-blockers and angiotensin-converting enzyme inhibitors can significantly decrease the morbidity and mortality of CHF. Further investigation is needed into whether increased use of prescription pharmaceuticals may reduce hospitalization rates and overall costs for CHF in this setting.

Recombinant human platelet-derived growth factor-BB (becaplermin) for healing chronic lower extremity diabetic ulcers: an open-label clinical evaluation of efficacy

Topically applied recombinant human platelet-derived growth factor-BB (becaplermin) is a new pharmacologically active therapy for chronic, neuropathic, lower extremity diabetic ulcers. In previous studies, becaplermin gel was administered once daily but dressings were changed twice daily. In the present study of 134 patients with diabetes mellitus and full thickness lower extremity ulcers, dressings were changed only once per day, simplifying the treatment regimen. Efficacy criteria included the percentage of patients achieving complete healing within the 20-week treatment period, the time to achieve complete healing, the rate of ulcer recurrence during the 6-month period following healing, and treatment compliance. Complete healing of ulcers was achieved in 57. 5% of patients, with a mean time to closure of 63 days and a recurrence rate of 21% at 6 months. Of the potential factors affecting ulcer healing, only drug compliance (p < 0.001), dressing compliance (p < 0.01), the presence of infection (p < 0.01), baseline ulcer area (p < 0.05), and baseline total wound evaluation score (p < 0.05) were significantly associated with healing. Results of this study further confirm the efficacy and safety of becaplermin gel for the treatment of lower extremity diabetic ulcers.

A rapid, automated enzymatic fluorometric assay for determination of D-arabinitol in serum

A rapid enzymatic fluorometric assay for measuring D-arabinitol in serum was developed using recombinant D-arabinitol dehydrogenase from Candida albicans (rArDH). rArDH was produced in Escherichia coli and purified by dye-ligand affinity chromatography. rArDH was highly specific for D-arabinitol, cross-reacting only with xylitol (4.9%) among all polyols tested. A Cobas Fara II centrifugal autoanalyzer (Roche) was used to measure NADH fluorometrically when rArDH and NAD were added to serum extracts, and D-arabinitol concentrations were calculated from standard curves derived from pooled human serum containing known amounts of D-arabinitol. The method was precise (mean intra-assay coefficients of variation [CVs], 0.8%, and mean interassay CVs, 1.6%) and rapid (3.5 min per assay) and showed excellent recovery of added D-arabinitol in serum (mean recovery rate, 101%). The mean and median D-arabinitol/creatinine ratios were 2.74 and 2.23 microM/mg/dl, respectively, for the 11 patients with candidemia compared to 1.14 and 1.23 microM/mg/dl, respectively, for 10 healthy controls (P < 0.01). These results confirm earlier studies showing that serum D-arabinitol measurement may help to promptly diagnose invasive candidiasis. The technique shows a significant improvement in terms of accuracy, cost, simplicity, specificity, and speed compared with gas chromatography, mass spectrometry, and earlier enzymatic assays.

Activation of PPARalpha or gamma reduces secretion of matrix metalloproteinase 9 but not interleukin 8 from human monocytic THP-1 cells

Peroxisome proliferator-activated receptors (PPARs) are ligand-activated transcription factors that directly control numerous genes of lipid metabolism by binding to response elements in the promoter. It has recently been proposed that PPARgamma may also regulate genes for proinflammatory proteins, not through PPRE binding but by interaction with transcription factors AP-1, STAT, and NF-kappaB. Recent studies with cultured human monocytes, however, have failed to observe an inhibitory effect of PPARgamma agonists on induced expression of TNFalpha and IL-6, genes known to be controlled by AP-1, STAT, and NF-kappaB. In a similar fashion, we show here that PPARalpha (fenofibrate) or PPARgamma (rosiglitazone) agonists failed to modulate LPS-induced secretion of IL-8 in THP-1 cells. When we made parallel observations on another gene, matrix metalloproteinase 9 (MMP-9), we were surprised to find profound downregulation of LPS-induced secretion by both PPARalpha or PPARgamma agonists. These findings suggest that PPAR may regulate only a subset of the proinflammatory genes controlled by AP-1, STAT, and NF-kappaB. Effects of PPARs on MMP-9 may account for the beneficial effect of PPAR agonists in animal models of atherosclerosis.

Protein Carbonyls in Bronchoalveolar Lavage Fluid in Mice, Rats and Hamsters Following Inhalation of Pigmentary Titanium Dioxide Particles

Elevation of protein carbonyls has been implicated in the clinical setting as a result of oxidant damage associated with a number of disease states in both humans and laboratory animals. Protein carbonyls, the product of oxidative modification of amino acid residues, may result from macrophage and neutrophil inflammatory responses to inhaled particles. We hypothesized that increased levels of protein carbonyl groups in the bronchoalveolar lavage fluid (BALF) may serve as a biomarker of oxidative stress in rodents exposed to extremely high airborne concentrations of poorly soluble particles (PSP) of low toxicity. The objective of the present study was to compare the BALF protein carbonyl levels in three rodent species following a subchronic PSP exposure known to result in pulmonary pathology in chronically exposed rats under similar conditions. Female Fischer 344 rats, B6C3F1 mice, and Syrian golden hamsters were identically exposed by whole-body inhalation to concentrations of aerosolized pigmentary titanium dioxide (TiO2)(MMAD and GSD, 1.42 and 1.3 μm, respectively) for 6 h/day and 5 days/wk for 13 wk. Groups of animals were exposed to 0, 10, 50, or 250 mg/m(3) of pigmentary TiO2. Levels of protein carbonyl groups in BALF were measured at the termination of the 13-wk exposure with an ELISA assay utilizing a 2,4-dinitrophenylhydrazine fluorescent probe. Protein carbonyl levels were elevated in rats at both the mid and high dose (50 and 250 mg/m(3)), while in mice and hamster the levels were elevated only at the high dose (250 mg/m(3)). The elevations in protein carbonyl levels paralleled changes in BALF-associated cytologic and biochemical inflammatory indices, including total protein levels and neutrophil counts. Inflammatory changes in all three species were limited to animals exposed to the highest concentrations of particles. Rats were the only species tested that had coincidental elevation of both protein carbonyls and a high inflammatory response measured in BALF following the 50-mg/m(3) exposure. These results suggest that the measurement of protein carbonyl groups in BALF may be a useful biomarker of particle-induced oxidant change, although this endpoint should be used in conjunction with other oxidative endpoints as a total assessment of oxidant stress.

Identification of surface residues of the monocyte chemotactic protein 1 that affect signaling through the receptor CCR2

The CC chemokine, monocyte chemotactic protein, 1 (MCP-1) functions as a major chemoattractant for T-cells and monocytes by interacting with the seven-transmembrane G protein-coupled receptor CCR2. To identify which residues of MCP-1 contribute to signaling though CCR2, we mutated all the surface-exposed residues to alanine and other amino acids and made some selective large changes at the amino terminus. We then characterized the impact of these mutations on three postreceptor pathways involving inhibition of cAMP synthesis, stimulation of cytosolic calcium influx, and chemotaxis. The results highlight several important features of the signaling process and the correlation between binding and signaling: The amino terminus of MCP-1 is essential as truncation of residues 2-8 ([1+9-76]hMCP-1) results in a protein that cannot stimulate chemotaxis. However, the exact peptide sequence may be unimportant as individual alanine mutations or simultaneous replacement of residues 3-6 with alanine had little effect. Y13 is also important and must be a large nonpolar residue for chemotaxis to occur. Interestingly, both Y13 and [1+9-76]hMCP-1 are high-affinity binders and thus affinity of these mutants is not correlated with ability to promote chemotaxis. For the other surface residues there is a strong correlation between binding affinity and agonist potency in all three signaling pathways. Perhaps the most interesting observation is that although Y13A and [1+9-76]hMCP are antagonists of chemotaxis, they are agonists of pathways involving inhibition of cAMP synthesis and, in the case of Y13A, calcium influx. These results demonstrate that these two well-known signaling events are not sufficient to drive chemotaxis. Furthermore, it suggests that specific molecular features of MCP-1 induce different conformations in CCR2 that are coupled to separate postreceptor pathways. Therefore, by judicious design of antagonists, it should be possible to trap CCR2 in conformational states that are unable to stimulate all of the pathways required for chemotaxis.

Overexpression of a dominant-negative allele of SEC4 inhibits growth and protein secretion in Candida albicans

Candida albicans SEC4 was cloned by complementing the Saccharomyces cerevisiae sec4-8 mutation, and its deduced protein product (Sec4p) was 63% identical to S. cerevisiae Sec4p. One chromosomal SEC4 allele in C. albicans CAI4 was readily disrupted by homologous gene targeting, but efforts to disrupt the second allele yielded no viable null mutants. Although this suggested that C. albicans SEC4 was essential, it provided no information about this gene's functions. Therefore, we constructed a mutant sec4 allele encoding an amino acid substitution (Ser-28-->Asn) analogous to the Ser-17-->Asn substitution in a trans-dominant inhibitor of mammalian Ras protein. GAL1-regulated expression plasmids carrying the mutant sec4 allele (pS28N) had minimal effects in glucose-incubated C. albicans transformants, but six of nine transformants tested grew very slowly in galactose. Incubation of pS28N transformants in galactose also inhibited secretion of aspartyl protease (Sap) and caused 90-nm secretory vesicles to accumulate intracellularly, and plasmid curing restored growth and Sap secretion to wild-type levels. These results imply that C. albicans SEC4 is required for growth and protein secretion and that it functions at a later step in the protein secretion pathway than formation of post-Golgi secretory vesicles. They also demonstrate the feasibility of using inducible dominant-negative alleles to define the functions of essential genes in C. albicans.

Identification of residues in the monocyte chemotactic protein-1 that contact the MCP-1 receptor, CCR2

The CC chemokine, MCP-1, has been identified as a major chemoattractant for T cells and monocytes, and plays a significant role in the pathology of inflammatory diseases. To identify the regions of MCP-1 that contact its receptor, CCR2, we substituted all surface-exposed residues with alanine. Some residues were also mutated to other amino acids to identify the importance of charge, hydrophobicity, or aromaticity at specific positions. The binding affinity of each mutant for CCR2 was assayed with THP-1 and CCR2-transfected CHL cells. The majority of point mutations had no effect. Residues at the N-terminus of the protein, known to be crucial for signaling, contribute less than a factor of 10 to the binding affinity. However, two clusters of primarily basic residues (R24, K35, K38, K49, and Y13), separated by a 35 A hydrophobic groove, reduced the level of binding by 15-100-fold. A peptide fragment encompassing residues 13-35 recapitulated some of the mutational data derived from the intact protein. It exhibited modest binding as a linear peptide and dramatically improved affinity when the region which adopts a single turn of a 3(10)-helix in the protein, which includes R24, was constrained by a disulfide bond. Additional constraints at the ends of the peptide, corresponding to the disulfide between the first and third cysteines in MCP-1, yielded further improvements in affinity. Together, these data suggest a model in which a large surface area of MCP-1 contacts the receptor, and the accumulation of a number of weak interactions results in the 35 pM affinity observed for the wild-type (WT) protein. The receptor binding site of MCP-1 also is significantly different from the binding sites of RANTES and IL-8, providing insight into the issue of receptor specificity. It was previously shown that the N-terminus of CCR2 is critical for binding MCP-1 [Monteclaro, F. S., and Charo, I. F. (1996) J. Biol. Chem. 271, 19084-92; Monteclaro, F. S., and Charo, I. F. (1997) J. Biol. Chem. 272, 23186-90]. Point mutations of six acidic residues in this region of the receptor were made to test their role in ligand binding. This identified D25 and D27 of the DYDY motif as being important. On the basis of our data, we propose a model in which the receptor N-terminus lies along the hydrophobic groove in an extended fashion, placing the DYDY motif near the basic cluster involving R24 and K49 of MCP-1. This in turn orients the signaling residues (Y13 and the N-terminus) for productive interaction with the receptor.

Effects of a thirteen-week inhalation exposure to ethyl tertiary butyl ether on fischer-344 rats and CD-1 mice

The 1990 Clean Air Act Amendments require that oxygenates be added to automotive fuels to reduce emissions of carbon monoxide and hydrocarbons. One potential oxygenate is the aliphatic ether ethyl tertiary butyl ether (ETBE). Our objective was to provide data on the potential toxic effects of ETBE. Male and female Fisher 344 rats and CD-1 mice were exposed to 0 (control), 500, 1750, or 5000 ppm of ETBE for 6 h/day and 5 days/wk over a 13-week period. ETBE exposure had no effect on mortality and body weight with the exception of an increase in body weights of the female rats in the 5000-ppm group. No major changes in clinical pathology parameters were noted for either rats or mice exposed to ETBE for 6 (rats only) or 13 weeks. Liver weights increased with increasing ETBE-exposure concentration for both sexes of rats and mice. Increases in kidney, adrenal, and heart (females only) weights were noted in rats. Degenerative changes in testicular seminiferous tubules were observed in male rats exposed to 1750 and 5000 ppm but were not seen in mice. This testicular lesion has not been reported previously for aliphatic ethers. Increases in the incidence of regenerative foci, rates of renal cell proliferation, and alpha2u-globulin containing protein droplets were noted in the kidneys of all treated male rats. These lesions are associated with the male rat-specific syndrome of alpha2u-globulin nephropathy. Increases in the incidence of centrilobular hepatocyte hypertrophy and rates of hepatocyte cell proliferation were seen in the livers of male and female mice in the 5000-ppm group, consistent with a mitogenic response to ETBE. These two target organs for ETBE toxicity, mouse liver and male rat kidney, have also been reported for methyl tertiary butyl ether and unleaded gasoline.

The prevalence of obesity and its determinants in urban and rural aging Mexican populations

OBJECTIVE

To determine the prevalence of obesity and its association to different variables in urban and rural older Mexican populations.

METHODS AND PROCEDURES

A cross-sectional study of three different Mexican communities. A total of 121 men and 223 women 60 years and older and 93 men and 180 women aged 35 to 59 years old were selected randomly for inclusion in the survey. A personal interview assessed demographic information, personal medical history and functional status and a 24-hour diet recall was obtained. The physical examination included anthropometric and blood pressure measurements. A fasting blood sample was obtained for measurements of lipids, insulin and glucose.

RESULTS

Obesity was highly prevalent in women, in individuals from the urban communities and diminished with advancing age. A BMI > or =30 kg/m2 was observed in 23.6% younger vs. 15.6% older adult men (p=0.21) and 28.4% younger vs. 19.7% older adult women (p = 0.06). The association of obesity with other variables was estimated using a stepwise multivariate logistic regression, increased insulin levels [Odds Ratio (OR) 1.68, p=0.006] and living in an urban area (OR 5.90, p<0.007) were variables independently associated to obesity in adult older individuals. In the younger adults, obesity was associated with hypertension (OR 2.74, p<0.0009), higher insulin levels (OR 1.31, p<0.03) and central adiposity (OR 2.97, p = 0.05), these relationship were not observed with gender, distribution of food or alcohol intake or other coronary risk factors.

CONCLUSIONS

The present survey confirms the high prevalence of obesity in the Mexican urban population that declines with advanced age. Studies in elderly population must consider the bias produced by increased early mortality in those individuals with a more unfavorable risk profile.

Enhancement of leukocyte response to lipopolysaccharide by secretory group IIA phospholipase A2

Secretory nonpancreatic group IIA phospholipase A2 (sPLA2), a lipolytic enzyme found in plasma, is thought to play an important role in inflammation. In patients with sepsis, a strong positive correlation is observed between the plasma level of sPLA2 and poor clinical outcome in sepsis. We have thus asked whether sPLA2 could play a role in enabling responses of cells to bacterial lipopolysaccharide (LPS), a key contributor to sepsis. In the presence of sPLA2, cellular responses to LPS were significantly increased. This was demonstrated in assays of LPS-stimulated interleukin-6 (IL-6) production in whole blood and binding of freshly isolated human polymorphonuclear neutrophils (PMN) to fibrinogen-coated surfaces. We further found that sPLA2 enhanced binding of labeled LPS to PMN, and that the sPLA2-mediated cell responses to LPS were all blocked by monoclonal antibodies directed against membrane CD14. Two properties ofsPLA2 may contribute to its activity to mediate responses to LPS. sPLA2 appears to bind LPS because pre-exposure of sPLA2 to LPS led to a dose-dependent increase in its ability to hydrolyze phospholid substrate, and incubation of sPLA2 with BODIPY-LPS micelles resulted in enhanced fluorescence, presumably from the disaggregation of the LPS aggregates. Additional studies demonstrated that the esterolytic function of sPLA2 is also needed both for the disaggregation of LPS and CD14-dependent cell stimulation. The precise mechanisms by which LPS-binding and esterolytic activity contribute to sPLA2 activity are not clear but our data strongly suggest that these activities result in interaction of LPS with CD14 and subsequent cell activation.

Diabetes knowledge and its determinants in a Mexican population

PURPOSE

The purpose of this study was to measure the level of diabetes knowledge in a representative group of Mexican individuals with diabetes and to identify the factors that influence it.

METHODS

A validated questionnaire was administered to 570 outpatients; 11.2% had Type 1 diabetes, 36.4% had Type 2 diabetes treated with insulin, and 52.2% had Type 2 diabetes treated with oral agents. Samples for HbA1c determination also were obtained.

RESULTS

The percentage of correct answers in each section of the questionnaire was low. Type 1 patients had the highest scores, followed by the insulin-treated Type 2 patients; those with chronic complications also had high scores. Educational background, attendance at diabetes courses, age, and HbA1c concentration were the main predictors of knowledge. Attendance at courses was influenced by the severity of the disease.

CONCLUSIONS

The amount of patient knowledge about diabetes-related issues was low in this representative Mexican population. The educational efforts were focused on those with the worst metabolic control and/or with diabetes complications.

Attachment of periosteal grafts to articular cartilage with fibrin sealant

Favorable results using fibrin sealants in vascular surgery and soft tissue reconstruction have prompted investigation of these biologic adhesives for orthopedic applications. One important recent application was as a sealant for periosteal grafts applied to defects in articular surfaces, a procedure that contained injected chondrocytes cultured in vitro. The low and variable adhesive strength of autologous fibrin substances prompted our investigation of allogeneic fibrin. An in vitro test method was developed to investigate the use of a fibrin sealant for attaching periosteal (bovine) patches to articular cartilage (bovine). Dermis-dermis (porcine) adhesion also was evaluated. In tests of the periosteum-to-cartilage bond performed in a physiological environment, we determined the effects of the following variables on the adhesive shear strength: set time, source of fibrinogen (bovine versus human), and fibrinogen concentration. A specially designed test rig was developed to avoid nonshear force components. Adhesive shear strength increased with fibrin set time for both fibrinogen concentrations and sources (p <.03). The 30-min set time yielded data with less variance than the 5-min set time in all cases except with the higher human fibrinogen concentration (50-80 mg/mL). While there was a trend at each set time towards greater shear strength with increased protein concentration (50-80 mg/mL versus 25-40 mg/mL), only the 5-min trial of the bovine product provided a significant advantage (p <.006). There was no significant difference in adhesive strength between the fibrin products produced with human and bovine fibrinogen. The periosteum-cartilage adhesive strengths obtained in our model were comparable to values recorded for the dermis-dermis bonding. The greater strength at the 30-min set time suggests that a certain time period of joint immobilization might be beneficial in procedures in which grafts are glued to articular cartilage. This study has shown that adhesive strengths achieved with fibrin glues in treating skin wounds also can be achieved in the attachment of periosteal grafts to articular cartilage.

Cryptococcus neoformans: virulence and host defences

Cryptococcus neoformans represents a model organism for the study of virulence and the host response. In this discussion, there is a focus on the genetic, molecular, and biochemical aspects of C. neoformans as it interacts with the host. Investigations into direct and indirect virulence phenotypes are now possible. The molecular aspects of two major virulence factors, capsule and melanin, are characterized. Yeast polyol metabolism through mannitol is examined as a potential biochemical pathway for virulence. The concept of C. neoformans differentially expressed genes within the host or in response to certain environmental cues can be used indirectly to identify potential virulence genes. However, despite significant progress in molecular pathogenesis with C. neoformans, the future of research in this area will require a certain critical mass of investigators to help share in the developmental costs which continue to occur.

Acarbose vs. bedtime NPH insulin in the treatment of secondary failures to sulphonylurea-metformin therapy in type 2 diabetes mellitus

OBJECTIVE

To evaluate the efficacy of acarbose in the treatment of secondary failures to sulphonylurea-metformin therapy, its comparison against bedtime NPH insulin, and to measure the changes in postprandial metabolism resulting from both treatments.

METHODS

One hundred type 2 diabetic patients in a secondary failure were included. The study begun with a run-in diet period of 6 weeks, in which an isocaloric diet was prescribed. Only subjects who continued hyperglycaemic were randomly assigned to placebo and acarbose (n = 17) or bedtime NPH insulin (n = 12). Acarbose (300 mg/day) or placebo were administered using a randomized, double blind, crossover design. Treatment periods of 3 months were separated by a 3-week washout period. Insulin was administered during 3 months. At the beginning and the end of each treatment period, an i.v. glucose tolerance test and a meal test were performed. Safety tests were done every 4 weeks.

RESULTS

Acarbose resulted in a small but significant improvement in fasting plasma glucose (13.5 +/- 2.4 vs. 11.3 +/- 3.9 mmol/l, p = 0.05), HbA1c (11.1 +/- 3.4 vs. 10.3 +/- 2.5%, P = 0.3) and in a decreased plasma glucose during the meal test. Bedtime insulin significantly decreased fasting plasma glucose (13.1 +/- 2.9 vs. 8.2 +/- 2.3 mmol/l, p < 0.01), HbA1c (11.7 +/- 2.9 vs. 9.4 +/- 2.7%, p < 0.01) and plasma cholesterol. No change in insulin secretion resulted from insulin and acarbose treatment.

CONCLUSIONS

Acarbose decreases blood glucose in secondary failure to sulphonylurea-metformin therapy; however, the decrease is not enough to reach the desired metabolic control. Bedtime NPH insulin is, by far, a more effective alternative.

Monomeric monocyte chemoattractant protein-1 (MCP-1) binds and activates the MCP-1 receptor CCR2B

To address the role of dimerization in the function of the monocyte chemoattractant protein-1, MCP-1, we mutated residues that comprise the core of the dimerization interface and characterized the ability of these mutants to dimerize and to bind and activate the MCP-1 receptor, CCR2b. One mutant, P8A*, does not dimerize. However, it has wild type binding affinity, stimulates chemotaxis, inhibits adenylate cyclase, and stimulates calcium influx with wild type potency and efficacy. These data suggest that MCP-1 binds and activates its receptor as a monomer. In contrast, Y13A*, another monomeric mutant, has a 100-fold weaker binding affinity, is a much less potent inhibitor of adenylate cyclase and stimulator of calcium influx, and is unable to stimulate chemotaxis. Thus Tyr13 may make important contacts with the receptor that are required for high affinity binding and signal transduction. We also explored whether a mutant, [1+9-76]MCP-1 (MCP-1 lacking residues 2-8), antagonizes wild type MCP-1 by competitive inhibition, or by a dominant negative mechanism wherein heterodimers of MCP-1 and [1+9-76]MCP-1 bind to the receptor but are signaling incompetent. Consistent with the finding that MCP-1 can bind and activate the receptor as a monomer, we demonstrate that binding of MCP-1 in the presence of [1+9-76]MCP-1 over a range of concentrations of both ligands fits well to a simple model in which monomeric [1+9-76]MCP-1 functions as a competitive inhibitor of monomeric MCP-1. These results are crucial for elucidating the molecular details of receptor binding and activation, for interpreting mutagenesis data, for understanding how antagonistic chemokine variants function, and for the design of receptor antagonists.