Meningeal SWI/SNF related, matrix-associated, actin-dependent regulator of chromatin, subfamily B member 1 (SMARCB1)-deficient tumours: an emerging group of meningeal tumours.

AIMS: Bi-allelic inactivation of SWI/SNF related, matrix-associated, actin-dependent regulator of chromatin, subfamily B member 1 (SMARCB1; also known as INI1) and loss of immunohistochemical expression of SMARCB1 define the group of SMARCB1-deficient tumours. Initially highlighted in malignant rhabdoid tumours, this inactivation has subsequently been observed in several intra and extracranial tumours. To date, primary meningeal SMARCB1-deficient tumours have not been described. We report two cases of meningeal SMARCB1-deficient tumours occurring in adults. METHODS: We performed immunohistochemical analyses, comparative genomic hybridization, fluorescence in situ hybridization and targeted next-generation sequencing. RESULTS: The first meningeal tumour was a solitary mass, composed of rhabdoid, adenoid, chordoid and sarcomatoid areas. The second case presented as multiple, bilateral, supra and infratentorial nodules, was composed of fusiform and ovoid cells embedded in a myxoid stroma. Tumour cells were positive for epithelial membrane antigen (EMA), vimentin and CD34 and negative for SMARCB1 and meningothelial, melanocytic, muscular, glial markers. In the first case, one allele of SMARCB1 was completely deleted, whereas in the second case, loss of expression of SMARCB1 was observed as a consequence of a homozygous deletion of SMARCB1. CONCLUSIONS: The phenotype and genotype of these two cases did not fit diagnostically with entities already known to be SMARCB1-deficient tumours. As both tumours shared common features, they are regarded as belonging to an emerging group of primary meningeal SMARCB1-deficient tumours, not described to date. To facilitate the identification and characterization of these tumours, we recommend SMARCB1 immunohistochemistry for primary meningeal tumours which are difficult to classify, especially if immunopositive for EMA and CD34.

Cre-loxP-mediated inactivation of the alpha6A integrin splice variant in vivo: evidence for a specific functional role of alpha6A in lymphocyte migration but not in heart development.

Two splice variants of the alpha6 integrin subunit, alpha6A and alpha6B, with different cytoplasmic domains, have previously been described. While alpha6B is expressed throughout the development of the mouse, the expression of alpha6A begins at 8.5 days post coitum and is initially restricted to the myocardium. Later in ontogeny, alpha6A is found in various epithelia and in certain cells of the immune system. In this study, we have investigated the function of alpha6A in vivo by generating knockout mice deficient for this splice variant. The Cre- loxP system of the bacteriophage P1 was used to specifically remove the exon encoding the cytoplasmic domain of alpha6A in embryonic stem cells, and the deletion resulted in the expression of alpha6B in all tissues that normally express alpha6A. We show that alpha6A-/- mice develop normally and are fertile. The substitution of alpha6A by alpha6B does not impair the development and function of the heart, hemidesmosome formation in the epidermis, or keratinocyte migration. Furthermore, T cells differentiated normally in alpha6A-/- mice. However, the substitution of alpha6A by alpha6B leads to a decrease in the migration of lymphocytes through laminin-coated Transwell filters and to a reduction of the number of T cells isolated from the peripheral and mesenteric lymph nodes. Lymphocyte homing to the lymph nodes, which involves various types of integrin-ligand interactions, was not affected in the alpha6A knockout mice, indicating that the reduced number of lymph node cells could not be directly attributed to defects in lymphocyte trafficking. Nevertheless, the expression of alpha6A might be necessary for optimal lymphocyte migration on laminin in certain pathological conditions.

Herlitz junctional epidermolysis bullosa keratinocytes display heterogeneous defects of nicein/kalinin gene expression.

Previous studies have correlated the Herlitz junctional epidermolysis bullosa (H-JEB) to an altered expression of the basement membrane component nicein/kalinin. This heterotrimeric glycoprotein appears to be present in H-JEB tissues in an abnormal form, because a number of antibodies specific to the protein either do not react with or weakly stain the epidermal basement membranes of most of the patients. With cDNA probes encoding each subunit of nicein and polyclonal antibodies raised against bacterial fusion polypeptides corresponding to the individual chains of the protein, we have molecularly analyzed the expression of nicein in H-JEB tissues and cultured keratinocytes. By immunohistochemistry, Northern blot, and protein analysis, we show a defective synthesis of one of the nicein subunits in six cases of H-JEB from five different consanguineous families. In two patients, the disease correlates with an impaired synthesis of the nicein B2 (nic B2) chain, in three others with that of the B1 (nic B1) chain, and in a sixth patient with that of the heavy A (nic A) chain. In this report, we thus demonstrate that H-JEB is a genetically heterogeneous disease and we provide strong evidence that the genes of nicein are the candidates for this genodermatosis.

Dairy cattle exploratory and social behaviors: is there an effect of cloning?

While an increasing number of animals are produced by means of somatic cloning, behavioral studies on cloned animals are still rare. The aim of this study was to investigate whether the somatic cloning procedure has an influence on locomotion, exploratory, vocal and social behaviors of heifers. Ten heifers were used in the present study. Five of them were cloned heifers derived from somatic cells of three different Prim'Holstein cows and five others were same-age control heifers produced by artificial insemination. In addition to observations of social behaviors in the stable group, each animal was placed individually for a short time in an unfamiliar environment. Our results failed to show any statistical differences between clones and their controls both in frequencies of agonistic and non-agonistic behaviors. However, cloned heifers showed significantly more non-agonistic and less agonistic behaviors towards other cloned partners than towards control ones. This result also stood for control heifers. As far as their Hierarchical Index was concerned, three cloned heifers were highest ranking and two others lowest ranking. In this herd, social dominance appeared to be linked to body weight and age rather than to a cloning effect. In an unfamiliar environment, cloned and control subjects exhibited the same level of locomotion and vocalization. However, cloned heifers showed more exploratory behaviors than did control ones. This difference could be due to environmental factors during the postnatal period rather than to cloning.

Combined genetic approaches yield a 48% diagnostic rate in a large cohort of French hearing-impaired patients.

Hearing loss is the most common sensory disorder and because of its high genetic heterogeneity, implementation of Massively Parallel Sequencing (MPS) in diagnostic laboratories is greatly improving the possibilities of offering optimal care to patients. We present the results of a two-year period of molecular diagnosis that included 207 French families referred for non-syndromic hearing loss. Our multi-step strategy involved (i) DFNB1 locus analysis, (ii) MPS of 74 genes, and (iii) additional approaches including Copy Number Variations, in silico analyses, minigene studies coupled when appropriate with complete gene sequencing, and a specific assay for STRC. This comprehensive screening yielded an overall diagnostic rate of 48%, equally distributed between DFNB1 (24%) and the other genes (24%). Pathogenic genotypes were identified in 19 different genes, with a high prevalence of GJB2, STRC, MYO15A, OTOF, TMC1, MYO7A and USH2A. Involvement of an Usher gene was reported in 16% of the genotyped cohort. Four de novo variants were identified. This study highlights the need to develop several molecular approaches for efficient molecular diagnosis of hearing loss, as this is crucial for genetic counselling, audiological rehabilitation and the detection of syndromic forms.

Peripherin, a neuronal intermediate protein, is stably expressed by neuroendocrine carcinomas of the skin, their xenograft on nude mice, and the corresponding primary cultures.

The histogenesis of neuroendocrine carcinomas of the skin is still controversial. To determine the degree of neural differentiation of these neoplasias, we studied the expression of intermediate filament proteins in tumoral tissues. Expressions of peripherin, the neurofilament protein NF-L, vimentin, and cytokeratin 8 were analyzed by immunohistochemical methods on 12 human primary tumors and 3 tumor xenografts on nude mice. Peripherin was detected in 10 primary tumors by immunofluorescence. The protein and the corresponding messenger RNA were identified by two-dimensional gel electrophoresis and Northern analysis in extracts of an immunofluorescence-negative tumor. Peripherin, NF-L, and cytokeratin 8 were detected in tumoral cells, whereas vimentin was found exclusively in the stroma. The histological and ultrastructural properties of the original cells of neuroendocrine carcinomas of the skin, as well as coexpression of peripherin, cytokeratin 8, and neurofilament polypeptides, were preserved in tumor xenografts and their primary cultures in vitro. These results bring new elements to the knowledge of the biology of neuroendocrine carcinomas of the skin and indicate that peripherin constitutes a marker for tumor identification.

Quantitative evaluation of fluorescein angiograms: microaneurysm counts.

This study describes a method for quantifying microaneurysms (MA) from fluorescein angiograms. The method was validated by the reproducibility of the number of MA in 30 angiograms read twice each by two independent observers; and by the absolute difference in MA counts between two readings by the same observer, and difference in numbers counted by two different observers. The precise location of each MA on two readings was also studied and the reproducibility of location varied from 60 to 71%, depending on the quality of the angiograms. Clinicians and technicians working in the same or in different centers obtained similar results. The coefficient of correlation between observers and between readings was satisfactory, r greater than 0.9. The method is easy to learn and the reproducibility allows for its use in clinical trials.

LRP5 gene polymorphisms and idiopathic osteoporosis in men.

Mutations in the low-density lipoprotein receptor-related protein 5 gene (LRP5) have demonstrated the role of LRP5 in bone mass acquisition. LRP5 variants were recently reported to contribute to the population-based variance in vertebral bone mass and size in males. To investigate whether LRP5 variants are implicated in idiopathic male osteoporosis, we studied 78 men with low BMD (<2.5 T score or < -2 Z score) aged less than 70 years (mean +/- SD: 50 +/- 16 years) in whom secondary causes of osteoporosis had been excluded and 86 controls (51 +/- 10 years). Genotypes and haplotypes were based on LRP5 missense substitutions in exons 9 (c.2047G > A, p.V667M) and 18 (c.4037C > T, p.A1330V), and their association with osteoporosis evaluated after adjustment for multiple clinical and environmental variables using logistic regression. The presence of osteoporosis was significantly associated with LRP5 haplotypes (P = 0.0036) independent of age (P = 0.006), weight (P = 0.004), calcium intake (P = 0.002), alcohol (P = 0.005) and tobacco (P = 0.004) consumption. Accordingly, the odds ratio for osteoporosis was 3.78 (95% CI 1.27-11.26, P < 0.001) in male carriers of haplotype 3 (c.2047A-4037T, n = 20 cases and 12 controls) versus homozygous carriers of haplotype 1 (c.2047G-4037C, n = 42 cases and 61 controls). In conclusion, these data indicate beyond a significant role for environmental factors, an association between LRP5 variants and idiopathic osteoporosis in males, pointing to a role of LRP5 in this disease.

Bone mass in middle-aged osteoporotic men and their relatives: familial effect.

Severe idiopathic osteoporosis in middle-aged men is still poorly understood. The aim of this study was to assess the contribution of genetic factors in these patients. We studied 38 men (mean age +/- SD, 50 +/- 11 years) presenting with vertebral or peripheral bone fractures due to primary osteoporosis and 73 of their relatives divided into four subgroups: 19 brothers, 22 sisters, 13 sons, and 19 daughters. The control group comprised 199 age-matched subjects. In all subjects, we measured bone mineral density (BMD) and calculated the Z score at the lumbar spine (LS) and femoral neck (FN) based on the fitted BMD value in the controls. LS BMD values were lower in each of the four subgroups compared with the age-matched controls. The mean Z score for the overall group of 73 relatives was decreased compared with the age-matched controls (-1. 28 +/- 1.48 at the LS and -1.03 +/- 1.19 at the FN) and was not influenced by gender or by whether the relatives were siblings or children. An LS Z score < -1) was found in 54.8% of the relatives of osteoporotic patients versus 17.4% of the control subjects (risk ratio, 3.2). Alcohol and tobacco abuse are well-known risk factors for osteoporosis in men. Among the 38 osteoporotic patients, 7 were heavy smokers (>20 pack-years), 8 were both heavy smokers and drinkers (>80 g/day for at least 10 years and gammaGT > 40 UI/l), and 23 had neither of these risk factors. BMD, Z score, and anthropometric data were the same in patients with and without risk factors. Decreases in LS and FN Z scores were similar in relatives of patients with and without risk factors. In conclusion, low BMD is observed in relatives of osteoporotic men with or without risk factors for osteoporosis, indicating that familial factors contribute to primary osteoporosis in middle-aged men.

BMD is reduced in HIV-infected men irrespective of treatment.

UNLABELLED: Osteoporosis has be reported to be a complication of active antiretroviral therapy of HIV infection. We studied 148 HIV-infected men stratified according to their treatment. Our data show that these patients have an average 9% decreased BMD, irrespective of their treatment. Low body mass index and high resorption markers were associated with low bone density. INTRODUCTION: Osteoporosis has been reported in HIV-infected (HIV+) patients, and it has been suggested that it may be linked to protease-inhibitor treatments (PI). MATERIALS AND METHODS: To assess this risk and to investigate its putative link with treatments, we compared the bone density of HIV+ men, who were either receiving treatment (including PI [PI+], n = 49; without PI [PI-], n = 51) or untreated (UT, n = 48). We included 81 age-matched control HIV-negative (HIV-) males (age, 40 +/- 8 years). RESULTS: BMD adjusted for age (Z-score) was lower in the HIV+ patients at the lumbar spine (HIV+: -1.08 +/- 1.21, HIV-: -0.06 +/- 1.26, p < 0.001) and the femoral neck (HIV+: -0.39 +/- 1.05, HIV-: 0.25 +/- 0.87, p < 0.001). The prevalence of osteoporosis was 16% in HIV+ and 4% in HIV- subjects (p < 0.01). In the HIV+ subjects, the Z-score was correlated only to body mass index (r = 0.27 at lumbar spine and 0.35 at femoral neck). Untreated HIV+ patients had a negative Z-score (-0.82 +/- 1.15 for the lumbar spine), which was not different from the one of treated HIV+ patients. In the PI+ and PI- groups, the Z-score did not depend on the presence of lipodystrophy or the proportion of fat in the abdomen and legs measured by DXA. Markers of bone remodeling were measured in the 132 HIV+ and 35 HIV- subjects. Compared with controls, HIV+ patients had lower bone alkaline phosphatase and higher urinary cross-laps/Cr, which was negatively correlated with the Z-score at both the femoral neck (r = -0.22) and lumbar spine (r = -0.21). TNFalpha was increased in untreated compared with treated HIV+ subjects and was not correlated to the Z-score. CONCLUSION: Our cross-sectional study does not show any deleterious effect of the treatment but does indicate a decrease in bone density in HIV+ patients irrespective of the treatment. This low bone density is in part related to the low body weight and is associated with increased bone resorption.

Osteoporosis in patients on long-term home parenteral nutrition: a longitudinal study.

UNLABELLED: The prevalence of osteoporosis was investigated in 88 patients with intestinal failure (IF). Osteoporosis was found in 67%, dependent of body mass index and age when IF occurred. In 56 patients on HPN, followed prospectively, changes in bone density were dependent on the duration of HPN; older patients had a higher increase. INTRODUCTION: It has been suggested that low bone mass and negative bone balance may occur in adult patients receiving home parenteral nutrition (HPN). The aim of this study was to assess prospectively the prevalence of osteoporosis in intestinal failure (IF) patients and the changes in bone mineral density in those on long-term HPN and to analyze the factors that may influence the occurrence and evolution of osteoporosis. MATERIALS AND METHODS: Bone mineral density was measured at the lumbar spine and femoral neck in 88 IF patients. RESULTS: At the first bone mineral density determination (baseline), the prevalence of osteoporosis was 67% in this population (median age, 52 years). Ten percent of the patients with osteoporosis experienced fragility fractures. Osteoporosis was independent of age and gender but occurred earlier in patients who had received corticosteroids. At baseline, the lumbar Z-score was positively correlated mainly to body mass index and age when IF occurred; these two parameters explained 34% of the Z-score. Repeated measurements were performed in 56 patients during long-term HPN (mean duration, 5.5 +/- 1.2 years). The changes in Z-score at the lumbar spine were dependent on the age when IF occurred and on the duration of HPN, with a synergistic effect between them. The older the patients, the higher the increase in Z-score during HPN. CONCLUSION: HPN had no deleterious effect on cortical bone and actually improved trabecular bone in patients whose intestinal disease started after the age of 21 years.

Genetic and environmental factors affect bone density variances of families of men and women with osteoporosis.

Our aim was to assess the relative impacts of genetics and environment in the families of osteoporotic patients and identify the best subgroup of patients to investigate the genes associated with osteoporosis. We recruited 36 men and 47 women with osteoporosis (probands), median age of 52 and 68 yr, and all their siblings (90) and offspring (83). The families were classified as young or old on the basis of the median age of the probands. We measured the bone mineral density at the femoral neck (FN) and lumbar spine (LS) adjusted for age and weight and standardized (Z-score). Physical activity, nutritional calcium, and alcohol and tobacco consumption were investigated. We compared the mean Z-score using linear mixed model and assessed the familial resemblance using intraclass correlation. The mean Z-scores of the families of osteoporotic patients were significantly negative at FN and LS, with no intergeneration or intergender differences. At FN, but not at LS, the mean Z-score was independently lower in the families of male probands (mean +/- SD: -0.57 +/- 0.96, female: -0.18 +/- 0.85, P = 0.012) and in young families (-0.58 +/- 0.94, old families: -0.11 +/- 0.83, P = 0.006). This suggested that the lower Z-score in the families of men with osteoporosis was related to their younger age. There was significant phenotypic resemblance among members in the families. In the families of female probands, the correlation between the probands and her siblings was weak and disappeared after adjustment on environment, and a resemblance appeared within their children (FN: r = 0.61) suggesting that different environment had masked the resemblance in this subgroup. In the families of male probands, a strong resemblance persisted after adjusting for environment, (proband-offspring at FN: r = 0.46 and within offspring at FN: r = 0.66, at LS: r = 0.61). This showed that resemblance was independent of a common measurable environment in these families of men with osteoporosis. In conclusion, mainly young osteoporotic patients, most of whom were male in our study, are affected by the genetic component.

A novel beta 1 integrin isoform produced by alternative splicing: unique expression in cardiac and skeletal muscle.

The mRNA's of several integrin subunits are alternatively spliced in the region encoding cytoplasmic domains, that may potentially provide alternative integrin-cytoskeleton interactions and transmembrane signaling pathways. We identified a novel cytoplasmic tail variant of the human beta 1 subunit by reverse transcriptase polymerase chain reaction. This fourth beta 1 variant, named beta 1D, is specific for skeletal and cardiac muscle. The determined genomic organization of the 3'-region of the human beta 1 gene reveals that beta 1D is produced by alternative splicing of mRNA. In addition, we show that the expression of beta 1D is developmentally regulated during murine myoblast differentiation, suggesting a role for beta 1D in myogenesis.

Clinical outcomes and mortality after hip fracture: a 2-year follow-up study.

The aim of this study was to evaluate the burden of hip fractures, which occurred in the French region of Picardie, in 1992, among 1103 women and 356 men, whether the fractures occurred at home or in a community (i.e., patients who depended on a collective service). The data are part of the PICAROS study, which was designed to assess prospectively the outcome of patients as judged by clinical, economical, and quality of life factors. Patients and/or proxies were questioned during the 2nd or 3rd week following the fracture, and again at 3, 6, 12, and 24 months after the fracture. The survey was conducted by home interview. Recruitment criteria were: 1) all patients with a hip fracture as defined by the International Classification of Disease (ICD); 2) 20 years of age and over; 3) admitted to one of the 34 surgical units from the region, public and private, and had an operation or not. Patients with metastatic or myelomatous fractures or fractures on prothesis device were not included. For the present analysis, patients under 50 years of age were excluded. Among people aged 50 years and over, 3% of the general population lived in a community; 32% of hip fractures were from a community. Patients in a community, aged 60-69, had 15 times more risk of having a hip fracture than subjects of the same age at home. The excess risk decreased with age and stabilized over 85 years of age at two to threefold. During the 24 month follow-up, 394 women and 173 men died. Among those surviving, 87% were interviewed at 2 years. We analysed seven classes of complications, according to the ICD: (1) pressure sores and blisters; (2) pulmonary infections; (3) urinary infections; (4) surgical complications; (5) orthopedic complications; (6) thrombosis and embolisms; and (7) secondary hip fractures. Patients coming from a community had a higher risk of mortality, pressure sores, surgical complications, and pulmonary and urinary infections. From an economical perspective, the institutionalized population would seem to be a profitable target for the prevention of fractures and their complications.

Reduced bone mineral density in postmenopausal women self-reporting premenopausal wrist fractures.

Postmenopausal fractures are associated with low bone mass; however, the role of low peak bone mass in young adults in determining subsequent osteoporosis suggests that premenopausal fractures may also be relevant. We therefore sought to determine whether a self-reported previous history of premenopausal wrist and nonwrist fractures could also be associated with bone density and therefore be used to predict osteoporosis. We recruited 453 volunteer women with a median age of 64 years (range 50-83 years), with no metabolic bone disease, previous femoral neck fracture, or prevalent vertebral fracture. Bone density at the femoral neck (FN) and lumbar spine (LS) was measured using a Lunar DPX-L. As expected, the 319 women who did not report any fracture had a higher T score at LS (-0.93 +/- 1.44) than the 134 women who reported a previous fracture at any site and at any age (T score -1.60 +/- 1.21, p < 0.001). The findings for the FN were similar. Compared with fracture-free women, the women who reported a first wrist fracture before menopause now had a lower LS T score (-1.77 +/- 1.20, n = 15, p < 0.05), whereas those who reported a nonwrist fracture showed no significant decrease in their LS T score (-1.26 +/- 1.00, n = 36). When both wrist and nonwrist fractures had occurred after menopause, the T score was significantly lower. Twenty percent of the fracture-free women were osteoporosis patients. After adjusting for body weight, age, hormonal replacement therapy (HRT), and hip fracture in the family, the relative risk (RR) of osteoporosis for premenopausal wrist fractures was 2.7 (95% confidence interval 1.4-4.3) vs. 1.2 (0.7-2.4) for women with premenopausal nonwrist fractures. We conclude that self-reported premenopausal wrist fractures, but no other fractures occurring before menopause, are likely to be associated with osteoporosis at 65 years of age, and therefore constitute strong grounds for screening.

Calcitonin receptor mRNA in mononuclear leucocytes from postmenopausal women: decrease during osteoporosis and link to bone markers with specific isoform involvement.

Calcitonin inhibits bone resorption via its receptor (CTR) on osteoclasts. Two hCTR isoforms, hCTR1 and hCTR2, give proteins that differ in their structure and signaling pathways. We investigated whether specific isoforms or quantitative changes in total hCTR mRNA were associated with high bone resorption and turnover in menopause or osteoporosis. The hCTR mRNA in mononuclear blood cells of premenopausal (PreM), healthy (PostM), and osteoporotic (OsteoP) postmenopausal women was assessed using reverse-transcriptase polymerase chain reaction. hCTR1 and hCTR2 were investigated for 59 total RNA samples, and semiquantitative analysis of total hCTR mRNA was performed for 71. Serum calcitonin, free urinary deoxypyridinoline (D-Pyr), serum bone alkaline phosphatase (SBAP), and osteocalcin (SOC) were also evaluated. Serum calcitonin levels did not differ in PostM and OsteoP. The prevalence of each isoform was similar in the three groups. Healthy postmenopausal women and OsteoP with hCTR2 had lower bone turnover (D-Pyr: 6.79 +/- 0.54, n = 25; SBAP: 11.63 +/- 1.47, n = 26; SOC: 8.31 +/- 0.58, n = 26) than those without hCTR2 (D-Pyr: 9.90 +/- 1.95, n = 5; SBAP: 21 +/- 5.19, n = 5; SOC: 11.9 +/- 2.10, n = 5; p < 0.05). Total hCTR mRNA levels were not different in PreM and PostM. By contrast, values were strikingly lower in OsteoP (0.57 +/- 0.17, n = 28) than in PostM (2. 25 +/- 0.61, n = 19, p < 0.05) and negatively correlated with bone markers values in both. We suggest that a specific isoform and amounts of total hCTR mRNA are linked to increased bone resorption in postmenopausal osteoporosis.

Does increased platelet aggregation have a prognostic value in the deterioration of background diabetic retinopathy? The Damad Study Group.

Many case-control studies have suggested that increased platelet aggregation (PA) could be involved in the pathogenesis of diabetic microangiopathy. However, longitudinal data are needed to support this hypothesis. We consider here such an approach in the placebo group (93 diabetic patients) of a controlled clinical trial on the effect of PA inhibitors in the treatment of diabetic retinopathy (Damad program). We have measured spontaneous PA and PA induced by ADP, collagen and arachidonic acid before treatment and yearly during a 3-year period. The assessment of retinopathy was based on the changes in the number of microaneurysms present in the macular field as seen on fluorescein angiograms during follow-up. PA was estimated by maximal decrease in optical density. The lowest ADP concentration still able to induce irreversible aggregation was also determined. No significant correlations between any baseline PA measurements and end point criterion were found (all correlation coefficients lower than 0.20). No significant changes in mean PA were observed during follow-up. Within-subject variation of PA was markedly large accounting for 61% to 98% of the total variance of various measurements. Allowances for the main characteristics of diabetes made no substantial difference to the results. These negative findings can be partly attributed to the lack of reliability of PA tests. In our study, we conclude that PA tests are not useful measures for the prediction of evolution of background diabetic retinopathy.

Pharmacokinetics of aztreonam in patients with chronic renal failure.

The elimination kinetics of aztreonam (SQ 26,776), a new, completely synthetic, monocyclic beta-lactam antibiotic, were studied after the administration of a single 1g intravenous dose. Five healthy volunteers and 20 patients with various degrees of renal insufficiency were enrolled in this study. Concentrations of aztreonam in serum and urine were determined by both microbiological and high pressure liquid chromatography (HPLC) assays. The pharmacokinetic parameters for aztreonam were calculated on the basis of a 2-compartment open model. Serum concentrations of aztreonam at 10 minutes after administration were approximately 100 micrograms/ml in all subjects, regardless of renal function (HPLC assay). The mean serum half-life during the alpha-phase showed no important variation with renal function. The mean serum half-life during the beta-phase was 1.8 hours in normal subjects and 8.4 hours in haemodialysis patients (HPLC assay). There was a linear correlation between the serum clearance of aztreonam and creatinine clearance. The mean cumulative urinary recovery of aztreonam in 48 hours was 60 to 70% of the administered dose in normal subjects but this was reduced in the presence of renal insufficiency. SQ 26,992, the microbiologically inactive metabolite of aztreonam resulting from hydrolytic opening of the beta-lactam ring, was undetectable in the serum of normal subjects but was found in low levels in uraemic patients. Half of a 1g intravenous dose of aztreonam was eliminated during 4 hours of haemodialysis. Guidelines for administration of aztreonam in the presence of renal failure are given.

Olfactory memory in rats, cholinergic agents and benzodiazepine receptor ligands.

Drugs and their effects on olfactory learning processes in rats were tested using a modified version of the runway apparatus developed by Ades. Rats were first exposed to a conspecific urine sample and 24 h later were exposed to the same stimulus in the runway. Observations recorded the time spent investigating the urine and the number of sniffs at the site, these being considered to be indices of memory. Diazepam-treated rats (4 or 6 mg/kg) and scopolamine-treated rats (0.5 or 1 mg/kg) showed increases for both parameters. When both drugs were administered simultaneously, the impairing effect was potentiated. However, no changes in learning responses were observed in rats treated with physostigmine (0.125, 0.25, 0.5 mg/kg) or methyl beta-carboline-3-carboxylate (0.3, 0.5, 1 mg/kg), although the administration of physostigmine or methyl beta-carboline-3-carboxylate was shown to antagonize the impairing effect of diazepam or scopolamine respectively. These observations support the hypothesis of interactions existing between cholinergic agents and benzodiazepine receptor ligands and of such interactions affecting olfactory acquisition processes. The runway apparatus appears to be a valid candidate model to be used for the assessment of pharmacological influences on olfactory learning in rats.

Indomethacin increases 15-PGDH mRNA expression in HL60 cells differentiated by PMA.

We previously reported an induction of 15-hydroxyprostaglandin dehydrogenase type I mRNA (15-PGDH) expression accompanied by a decrease in prostaglandin E2(PGE2) levels during cord blood monocytes differentiation into preosteoclastic cells by 1,25 dihydroxyvitamin D3 (1,25 (OH)2D3). These results suggested a role of prostaglandin (PG) enzymes in adhesion and/or differentiation of monocytes. In the present work, we studied modulation of gene expression of PG metabolism enzymes mRNAs in HL60 cells differentiated by phorbol myristate acetate (PMA) into the monocyte/macrophage lineage. We showed that adhesion of HL60 induced by PMA causes an increase of cyclooxygenase 2 (COX 2) and 15-PGDH mRNAs. When adding indomethacin, a non steroidal antiinflammatory drug known to inhibit COX activity, the cells remained attached and expressed large amounts of 15-PGDH mRNA while COX 2 mRNA expression remained unchanged. Indomethacin, in association with PMA can consequently exert a dual control on key enzymes of PGE2 metabolism without modifying adhesion of the cells.