The effect of short-term treatment with micronized estradiol on bone turnover and gonadotrophins in older men

Evidence for the role of estrogen in male bone metabolism has been confirmed by studies on a man with a genetic defect in the estrogen receptor as well as men with aromatase defects. All exhibited tall stature, delayed epiphysial closure, decreased bone density and increased bone turnover. Estrogen is likely to affect bone turnover in men throughout life; therefore, we hypothesized that older men would show decreased bone resorption in response to estrogen therapy. To test our hypothesis, fourteen community-dwelling men with osteopenia of the femoral neck were treated for 9 weeks with micronized estradiol, 1 mg/d, a dose which is effective in postmenopausal women. Each subject served as his own control. Markers of bone resorption, N-terminal collagen crosslinks (NTX) and C-terminal collagen crosslinks (CTX) and markers of bone formation, osteocalcin (OC) and bone specific alkaline phosphatase (BSAP) were measured every 3 weeks during a 9-week treatment period and 9 weeks post-treatment. Sex hormones, gonadotrophins and calciotropic hormones were measured at baseline, 9 weeks on treatment and 9 weeks post- treatment. After 9 weeks of treatment, estradiol and estrone levels increased significantly by greater than 6-fold and 15-fold, respectively. SHBG levels increased significantly by 17%. Testosterone and free testosterone levels decreased significantly by 27% and 34%, respectively. Markers of bone resorption showed wide variation at baseline and while on treatment. There was no correlation between changes in bone markers and changes in estrogen levels. During treatment, 11 patients showed a decrease of NTX or CTX, but three showed an increase. These three and one other subject had high initial levels of FSH and LH, suggesting some degree of primary gonadal failure, which decreased during estrogen therapy. Thus, the change in NTX (and CTX) after 9 weeks of E2 treatment was correlated with initial FSH (r= -.66, p= .01) and LH (r= -.73, p= .003) values. In addition, the largest decrease in free testosterone at 9 weeks was correlated with the higher values for NTX, CTX and BAP (r=-0.66, -0.68, -0.70 respectively; p< or =.01 for each of the markers). Treatment was generally well tolerated. Side effects of treatment were minimal, and included breast tenderness and decreased libido which reversed after treatment. We conclude that it is feasible to give low dose estrogen to healthy older men, but that the effects on bone turnover are not consistent. Changes in central feedback and in endogenous sex hormone production may alter the response of bone turnover to exogenous estrogen in this population.

A rapid and sensitive reporter gene that uses green fluorescent protein expression to detect chemicals with estrogenic activity

A reporter gene sequence was constructed within a eukaryotic expression vector. The altered plasmid contained 2 sequential estrogen response elements (ERE) coupled to a human phosphoglycerate kinase (PGK) promoter inserted upstream from a cDNA sequence encoding enhanced green fluorescent protein (GFP) with a 3'-polyadenylation signal. The plasmid was linearized and transfected into MCF-7 cells, a human breast cancer-derived line that expresses the estrogen receptor (ER). No selectable marker was present in the plasmid, requiring stably transfected cells to be selected by fluorescence-activated cell sorting based on GFP expression after the cells were treated with 10(-9) M 17beta-estradiol (E2). Stably transfected MCF-7 cells (MCF7-ERE) exhibited 2000-3000 times more fluorescence at 488 nm excitation and 512 nm emission than non-transfected cells. MCF7-ERE cells exhibited a linear increase in GFP expression induced over a range of 10(-12) M E2, a concentration giving 2 times the background expression, to maximal expression at 3 x 0(-10) M E2. From the maximal level, GFP expression plateaued, and then declined when E2 was increased to the highest concentration tested, 10(-7) M. 4-Hydroxytamoxifen (TFN-OH) treatment of cells produced a dose-dependent inhibition of E2-induced GFP expression, indicating the interaction of ER in the regulation of GFP gene expression. A series of estrogenic chemicals were evaluated for their capacity to induce GFP expression in MCF7-ERE cells, showing induced expression of GFP at concentrations 2-4 log units higher than the E2 concentration giving maximal GFP expression. The ERE-PGK-GFP reporter gene system is capable of rapid GFP expression in the presence of low concentrations of E2, and of quantifying estrogenicity of chemicals compared with a standard curve of the natural ligand, 17beta-estradiol.

Inverted duplication of the distal short arm of chromosome 3 associated with lobar holoprosencephaly and lumbosacral meningomyelocele

A fetus with lobar holoprosencephaly and lumbosacral meningomyelocele associated with duplication of the short arm of chromosome 3 is reported. The anomalies were detected on fetal ultrasound at 20 weeks' gestation and the autopsy findings correlated well with the prenatal findings. The fetal karyotype was 46,XY,der(3)del(3)(p26) dup(3)(p26p21.3). The association of holoprosencephaly with duplication 3p is well known, but to the best of our knowledge this is the first reported association of meningomyelocele with 3p duplication. These findings suggest that a gene or genes with a crucial role in central nervous system development are located on the short arm of chromosome 3.

Interaction of Pex5p, the type 1 peroxisome targeting signal receptor, with the peroxisomal membrane proteins Pex14p and Pex13p

Pex5p, a receptor for peroxisomal matrix proteins with a type 1 peroxisome targeting signal (PTS1), has been proposed to cycle from the cytoplasm to the peroxisomal membrane where it docks with Pex14p and Pex13p, the latter an SH3 domain-containing protein. Using in vitro binding assays we have demonstrated that binding of Pex5p to Pex14p is enhanced when Pex5p is loaded with a PTS1-containing peptide. In contrast, Pex5p binding to Pex13p, which involves only the SH3 domain, occurs at 20-40-fold lower levels and is reduced when Pex5p is preloaded with a PTS1 peptide. Pex14p was also shown to bind weakly to the Pex13p SH3 domain. Site-directed mutagenesis of the Pex13p SH3 domain attenuated binding to Pex5p and Pex14p, consistent with both of these proteins being binding partners for this domain. The SH3 binding site in Pex5p was determined to lie within a 114-residue peptide (Trp(100)-Glu(213)) in the amino-terminal region of the protein. The interaction between this peptide and the SH3 domain was competitively inhibited by Pex14p. We interpret these data as suggesting that docking of the Pex5p-PTS1 protein complex at the peroxisome membrane occurs at Pex14p and that the Pex13p SH3 domain functions as an associated component possibly involved in sequestering Pex5p after relinquishment of the PTS1 protein cargo to components of the translocation machinery.

Association between parental perception of children's vulnerability to illness and management of children's asthma

This study examined the relationship between asthma management strategies used by parents and parental perception of children's vulnerability to illness. Home interviews were conducted with 101 parents of children previously hospitalized with asthma. The child vulnerability scale (CVS) was employed to assess parents' perception of their children's vulnerability to illness. The asthma severity index (ASI) was used to measure the frequency and intensity of asthma symptoms experienced by children in the preceding 12 months. Five markers of parental asthma management were assessed: (i) school absences; (ii) visits to the general practitioner (GP); (iii) visits to the emergency room (ER); (iv) hospitalizations; and (v) whether children are using a regular preventer. After controlling for the frequency and intensity of children's asthma symptoms, parents who perceived that their children were more vulnerable to medical illness were significantly more likely to keep their children home from school (P = 0.01), were more likely to take their children to the GP for acute asthma care (P = 0.02), and were more likely to be giving their children regular preventer medication (P = 0.02). In contrast, the use of tertiary pediatric care services was not significantly associated with parental perceptions of their children's vulnerability. The results suggest that parental attitudes and beliefs about the vulnerability of their children to illness were associated with greater use of GP services by parents and more frequent school absences for children. The use of hospital services by parents appeared to be more strongly associated with the actual level of children's asthma symptoms than their vulnerability to illness.

Comparison of serum and urine assays for biochemical markers of bone resorption in postmenopausal women with and without hormone replacement therapy and in men

Biochemical markers of bone resorption have been used to characterize metabolic bone disease and assess therapeutic response. Most studies have used the urinary measurement of collagen crosslinks, but serum assays have recently been developed that may have less analytic and biologic variability. In the present study, we measured urine and serum N- and C-terminal crosslinked telopeptides of type I collagen (NTX and CTX) and serum bone sialoprotein (BSP) in postmenopausal women with or without hormone replacement therapy (HRT) and in men of similar age. In these populations, the variability of serum and urine markers was similar, except that serum NTX showed somewhat lower variability in postmenopausal women. Urine and serum assays correlated well with one another and were significantly lower in postmenopausal women on HRT compared with untreated women. The difference in women on HRT was similar for sNTX, uNTX and BSP (35-40%) and greater for sCTX and uCTX (52-53%). There was an inverse correlation between markers and bone mineral density, largely attributable to the high correlation in women not on HRT. Fractional excretion of NTX and CTX were estimated at 0.20+/-0.07 and 0.44+/-0.11, respectively. These values were independent of the concentration of the marker or of creatinine in the urine. We conclude that serum markers are useful measures of bone resorption in these populations, in whom the use of such markers is likely to be helpful in the management of osteoporosis.

Thalamic and amygdala-hippocampal volume reductions in first-degree relatives of patients with schizophrenia: an MRI-based morphometric analysis

BACKGROUND

Schizophrenia is characterized by subcortical and cortical brain abnormalities. Evidence indicates that some nonpsychotic relatives of schizophrenic patients manifest biobehavioral abnormalities, including brain abnormalities. The goal of this study was to determine whether amygdala-hippocampal and thalamic abnormalities are present in relatives of schizophrenic patients.

METHODS

Subjects were 28 nonpsychotic, and nonschizotypal, first-degree adult relatives of schizophrenics and 26 normal control subjects. Sixty contiguous 3 mm coronal, T1-weighted 3D magnetic resonance images of the brain were acquired on a 1.5 Tesla magnet. Cortical and subcortical gray and white matter and cerebrospinal fluid (CSF) were segmented using a semi-automated intensity contour mapping algorithm. Analyses of covariance of the volumes of brain regions, controlling for expected intellectual (i.e., reading) ability and diagnosis, were used to compare groups.

RESULTS

The main findings were that relatives had significant volume reductions bilaterally in the amygdala-hippocampal region and thalamus compared to control subjects. Marginal differences were noted in the pallidum, putamen, cerebellum, and third and fourth ventricles.

CONCLUSIONS

Results support the hypothesis that core components of the vulnerability to schizophrenia include structural abnormalities in the thalamus and amygdala-hippocampus. These findings require further work to determine if the abnormalities are an expression of the genetic liability to schizophrenia.

Safe use of valproic acid during pregnancy

QUESTION

I have an epileptic patient who plans pregnancy. It took us years to control her seizures, and valproic acid seems to be the only way to control them. What is the risk to her fetus?

ANSWER

Neural tube defects (NTDs) are the most common of the major anomalies associated with in utero exposure to valproic acid. About 1% to 2% of exposed fetuses suffer adverse effects.

Retinoic acid-dependent upregulation of mouse folate receptor-alpha expression in embryonic stem cells, and conservation of alternative splicing patterns

The action of retinoic acid (RA) in normal development and differentiation is mediated by changes in the expression of RA-responsive target genes. We used differential display reverse transcriptase polymerase chain reaction (RT-PCR) to identify RA-responsive genes expressed in embryonic stem (ES) cells and found that murine folate receptor-alpha (FR-alpha) expression is rapidly induced by RA treatment. The observed increase in FR-alpha expression occurs within 3h, is independent of protein synthesis and does not occur when ES cells are differentiated by removal of leukaemia inhibitory factor (LIF), evidence that the response to RA is both direct and specific. Two messenger RNA (mRNA) isoforms of FR-alpha featuring novel sequence in the 5' untranslated region (UTR) were cloned, and both were found to be upregulated by RA. Other splice variants in both the 5' UTR and 3' UTR of FR-alpha mRNA were also identified. There is a striking similarity between these splicing patterns and those reported for human FR-alpha, which also generates multiple isoforms by alternative splicing in the 5' and 3' UTR. The conservation of these splicing patterns in the non-coding regions of the FR-alpha gene between mouse and human suggests that these regions, and in particular the 5' UTR, play an important role in regulating expression of this gene.

Non-ionic bulky Gd(III) DTPA-bisamide complexes as potential contrast agents for magnetic resonance imaging

A series of new diethylene triamine pentaacetic acid (DTPA)-bisamide chelates containing bulky alkyl and aryl side chains have been prepared and characterized. Nuclear magnetic relaxation dispersion profiles were measured for the neutral gadolinium [Gd(III)] DTPA-bisamide complexes in water solution, and their chemical exchange times (tau(m)) were found to be in the range of 1.4 to 4.9 micros. Significant enhancements of solvent proton relaxation rates were observed between 10 and 50 MHz for one of the complexes of the series [Gd(III)-DTPA-bis-2-ethylhexylamide] in human serum albumin (HSA) solution, indicating the formation of a paramagnetic macromolecular adduct. The binding association constant K(A) of the complex and the albumin 5.7 x 10(3) M(-1) was obtained, and the relaxivity of the fully bound adduct was determined to be 13.8 mM(-1) s(-1) at 20 MHz and 25 degrees C. The high value of K(A) makes the above derivative a good potential blood pool contrast agent at the physiological HSA concentration.

Pregnancy outcome following gestational exposure to organic solvents: a prospective controlled study

CONTEXT

Numerous women of childbearing age are exposed occupationally to organic solvents. Previous retrospective studies have reported conflicting results regarding teratogenic risk.

OBJECTIVE

To evaluate pregnancy and fetal outcome following maternal occupational exposure to organic solvents.

DESIGN

A prospective, observational, controlled study.

SETTING

An antenatal counseling service in Toronto, Ontario.

PATIENTS

One hundred twenty-five pregnant-women who were exposed occupationally to organic solvents and seen during the first trimester between 1987 and 1996. Each pregnant woman who was exposed to organic solvents was matched to a pregnant woman who was exposed to a nonteratogenic agent on age (+/-4 years), gravidity (+/-1), and smoking and drinking status.

MAIN OUTCOME MEASURE

Occurrence of major congenital malformations.

RESULTS

Significantly more major malformations occurred among fetuses of women exposed to organic solvents than controls (13 vs 1; relative risk, 13.0; 95% confidence interval, 1.8-99.5). Twelve malformations occurred among the 75 women who had symptoms temporally associated with their exposure, while none occurred among 43 asymptomatic exposed women (P<.001). (One malformation occurred in a woman for whom such information was missing.) More of these exposed women had previous miscarriage while working with organic solvents than controls (54/117 [46.2%] vs 24/125 [19.2%]; P<.001). However, exposed women who had a previous miscarriage had rates of major malformation that were similar to exposed women who had no previous miscarriage.

CONCLUSIONS

Occupational exposure to organic solvents during pregnancy is associated with an increased risk of major fetal malformations. This risk appears to be increased among women who report symptoms associated with organic solvent exposure. Women's exposure to organic solvents should be minimized during pregnancy. Symptomatic exposure appears to predict higher fetal risk for malformations.

Perception of first- and second-order motion: separable neurological mechanisms?

An unresolved issue in visual motion perception is how distinct are the processes underlying "first-order" and "second-order" motion. The former is defined by spatiotemporal variations of luminance and the latter by spatiotemporal variations in other image attributes, such as contrast or depth. Here we describe two neurological patients with focal unilateral lesions whose contrasting perceptual deficits on psychophysical tasks of "first-order" and "second-order" motion are related to the maps of the human brain established by functional neuroimaging and gross anatomical features. We used a relatively fine-grained neocortical parcellation method applied to high-resolution MRI scans of the patients' brains to illustrate a subtle, yet highly specific dissociation in the visual motion system in humans. Our results suggest that the two motion systems are mediated by regionally separate mechanisms from an early stage of cortical processing.

Identification of a mouse orthologue of the human ras-GAP-SH3-domain binding protein and structural confirmation that these proteins contain an RNA recognition motif

Human ras-GTPase-activating protein (GAP120) SH3-domain-binding protein (G3BP) has recently been identified on the basis of its specific binding to the GAP120 SH3 binding domain. Here we report the identification of a mouse G3BP cDNA and the confirmation by three dimensional modelling of an RNA recognition motif (RRM) in the encoded protein. Mouse G3BP also contains an RGG domain, an acid-rich amino acid domain, and several SH3 domain-binding consensus sequences, indicating that mammalian G3BPs represent a new family of signal transduction proteins which connect tyrosine kinase-linked receptors to cellular RNA metabolism.

The epidemiology of cocaine and opiate abuse in urban Canada

This study describes the epidemiology of cocaine and heroin abuse in urban Canada as part of an initial report on a national substance abuse surveillance system, the Canadian Community Epidemiology Network on Drug Use. Data pertaining to prevalence of use, law enforcement, treatment, morbidity and mortality of cocaine and heroin were obtained from the appropriate health and law enforcement institutions in six sentinel cities: Vancouver, Calgary, Winnipeg, Toronto, Montreal and Halifax. Cocaine and heroin appear to be more available in Vancouver than in the remaining cities. In all CCENDU cities, large proportions of persons in treatment programs for substance abuse identified cocaine as their major addiction; however, there is considerable variation in treatment utilization regarding heroin. Vancouver ranks first in terms of the per capita number of cocaine- and heroin-related hospital separations and mortality rate. Cocaine abuse appears to be an emerging problem in Calgary, Winnipeg and Halifax, and opiate abuse appears to be an emerging problem in Calgary.

Valproic acid use in psychiatry: issues in treating women of reproductive age

Valproic acid, a well known anticonvulsant, is being used by psychiatrists increasingly to manage bipolar and other affective disorders. Because of the demographics of the population affected by such psychiatric conditions, more women of childbearing age are likely to be exposed to this teratogenic drug. Neural tube defects (NTD) are the most common of the major anomalies associated with in utero valproic acid exposure, and are estimated to occur in 1% to 2% of exposed fetuses. Other teratogenic effects include facial dysmorphism, congenital cardiac defects, limb reduction defects and other skeletal anomalies. Prenatal diagnosis, in particular maternal serum alpha-fetoprotein screening and targeted ultrasonography, should be offered to all pregnant women exposed to valproic acid and couples need to be aware of the prenatal diagnostic options available to them. Periconceptual prophylaxis with high doses of folic acid is recommended for all women on valproic acid and counselling should also emphasize planning pregnancy to optimize folic acid supplementation. Psychiatrists should be aware of the teratogenic potential of valproic acid and know how to counsel their patients of reproductive age.

Visual loss in a returning traveller with tick typhus

Rickettsial diseases are increasingly found world-wide and should be considered in febrile patients returning from abroad. This case report describes the vasculitic complications of a patient returning from the Republic of South Africa with tick typhus.

Effective in vivo depletion of T cell subpopulations and loss of memory cells in cattle using mouse monoclonal antibodies

Conditions were established to obtain depletion of T lymphocyte subsets in lymphoid tissues of calves by injection of mouse monoclonal antibodies to T cell antigens. Adverse reactions were avoided by injecting small quantities of antibody, until target cells had disappeared from blood. Two different mechanisms appeared to be responsible for elimination of the target cells. Rapid depletion of T cells was associated with complement-binding antibody isotypes (IgG2a, IgM), suggesting a complement-mediated mechanism. Clearance of T cells after several days was observed with a non complement-binding isotype (IgG1), suggesting phagocytosis or induction of apoptosis as possible mechanisms. Clearance of the cells in peripheral blood and spleen was obtained with 10-20 mg of anti-CD4 or anti-CD8, but almost ten times as much was needed to obtain depletion of the cells in lymph nodes and Peyer's patches. Depletion lasted for 12 days for CD4 T cells and 3 weeks for CD8 T cells. Successful and lasting depletion (at least 2 weeks) was also obtained with other T cell reagents, such as anti-CD2 and anti-WC1 (gamma/delta T cells). Although B lymphocytes could be removed by a complement-binding antibody, complete depletion of these cells only lasted for a few hours, probably because B cells regenerate faster than T cells. T cell function was severely inhibited when CD4+ T cells were depleted. Stimulation of T cells with foot and mouth disease viral antigen (FMDV) in vaccinated calves was non-existent after depletion. Even 2 months after restoration of normal CD4 T cell levels in blood, activity to FMDV was low. This suggested that the depleted T cells were replaced by naive cells.

Cocaine decreases cortical cerebral blood flow but does not obscure regional activation in functional magnetic resonance imaging in human subjects

The authors used functional magnetic resonance imaging (fMRI) to determine whether acute intravenous (i.v.) cocaine use would change global cerebral blood flow (CBF) or visual stimulation-induced functional activation. They used flow-sensitive alternating inversion recovery (FAIR) scan sequences to measure CBF and blood oxygen level-dependent (BOLD) sensitive T2* scan sequences during visual stimulation to measure neuronal activation before and after cocaine and saline infusions. Cocaine (0.6 mg/kg i.v. over 30 seconds) increased heart rate and mean blood pressure and decreased end tidal carbon dioxide (CO2). All measures returned to baseline by 2 hours, the interinfusion interval, and were unchanged by saline. Flow-sensitive alternating inversion recovery imaging demonstrated that cortical gray matter CBF was unchanged after saline infusion (-2.4 +/- 6.5%) but decreased (-14.1 +/- 8.5%) after cocaine infusion (n = 8, P < 0.01). No decreases were detected in white matter, nor were changes found comparing BOLD signal intensity in cortical gray matter immediately before cocaine infusion with that measured 10 minutes after infusion. Visual stimulation resulted in comparable BOLD signal increases in visual cortex in all conditions (before and after cocaine and saline infusion). Despite a small (14%) but significant decrease in global cortical gray matter CBF after acute cocaine infusion, specific regional increases in BOLD imaging, mediated by neurons, can be measured reliably.