Biomedical subjects

F Aguado

Publications and source records attributed to F Aguado.

At least 37 records · Page 2Linked to original sources

PubMed1997

Vertebral and metacarpal morphometry as indicators of nutritional improvement.

Because of the importance of nutrition in the development of bone mass, we studied the nutritional state, and bone state by means of metacarpal radiogrammetric measurements and vertebral morphometry in a group of 40 premenopausal women born between 1960 and 1970, mean age 29 +/- 5 years, and in another group of 40 postmenopausal women born between 1934 and 1944, mean age 55 +/- 4 years. Both groups were considered normal, the main characteristic distinguishing them being that the women born between 1934 and 1944 grew up in a period of widespread malnutrition in Spain and the women born between 1960 and 1970 grew up in a period of normal nutrition. Protein, carbohydrate and fat intake in these two periods differed significantly (p < 0.0001 in the three cases by Fischer's exact test). The values of the metacarpal measurements, anterior height of the dorsal vertebrae from T-4 to T-12, and posterior height from L-1 to L-4 between the premenopausal and postmenopausal groups of women were significantly different (p < 0.001) (Anova test). These findings show the importance of nutrition in the development of bone mass during childhood.

Absorptiometry, Photon↗

PubMed1997

Cortical bone resorption in osteoporosis.

A study was made of 110 women: 35 healthy premenopausal, 40 healthy postmenopausal, and 35 women diagnosed as having postmenopausal osteoporosis. The postmenopausal women had similar ages and years since menopause (YSM). In all of the women, total bone mass was evaluated by dual-energy X-ray absorptiometry and metacarpal morphometry was evaluated by radiogrammetry on the second metacarpal of the nondominant hand, performed by computed radiography. An external metacarpal diameter of >/=7.4 mm was required as proof of having developed an adequate peak bone mass. The endosteal diameter, which is indicative of bone resorption in both groups of postmenopausal women, obtained in the postmenopausal groups was subtracted from the endosteal diameter obtained in the premenopausal group and the resulting figure was divided by the years since menopause to calculate the rate of cortical bone resorption/year for each group. The endosteal diameters values differed in the three groups studied (P < 0.0001): 3.2 +/- 0.7 mm in the healthy premenopausal women; 3.9 +/- 0.6 mm in the healthy postmenopausal women; and 4.7 +/- 0.5 mm in the osteoporotic postmenopausal women. The rate of cortical bone resorption was 0.068 +/- 0.002 mm/YSM (years since menopause) in the osteoporotic postmenopausal women and 0.033 +/- 0.003 mm/YSM in the healthy postmenopausal women (P < 0. 0001). These figures reflect the importance of bone resorption, as opposed to deficient bone formation, as a cause of osteoporosis.

Absorptiometry, Photon↗

PubMed1997

Comparison of three bone densitometry methods in osteoporotic women.

Three techniques of bone mass measurement were evaluated in the diagnosis of postmenopausal osteoporosis; the overlap in the measurements and the capacity for discriminating was determined among 51 postmenopausal normal (mean age 66.6 +/- 8.4 years) and 42 postmenopausal osteoporotic women (mean age 68.5 +/- 7.5 years). All bone mass was evaluated by total body bone mineral content (BMCTB), density (BMDTB), ultrasound bone velocity (UBV) in proximal phalanxes 2-5 of the nondominant hand (UBV = mean value of all ultrasound measurements), and peripheral quantitative computed tomography of the nondominant forearm (pQCT). BMCTB was found to be significantly better (P < 0.0001) for diagnosing postmenopausal osteoporosis than the other methods; both cortical and trabecular pQCT measurements were more discriminating than the corresponding UBV measurements (P < 0.001). T-score values in normals, subjects versus osteoporotic ones were BMCTB -1.15 +/- 0.79 versus -3.17 +/- 0.74; BMDTB -1.01 +/- 0.97 versus -3.28 +/- 0.81; UBV -1.51 +/- 1.02 versus -2.34 +/- 1.21; trabecular-pQCT -0.40 +/- 0.72 versus -1.57 +/- 0.37; cortical-pQCT -1.00 +/- 0.87 versus -2.67 +/- 0.53; and total-pQCT -0.65 +/- 1.01 versus -2.34 +/- 0.27, respectively. The overlap in values between the postmenopausal normal and postmenopausal osteoporotic groups was 50% with UBV, 6% with BMCTB, 9% with BMDTB, 25% with cortical pQCT, and 42% with trabecular pQCT. BMCTB, BMDTB, UBV, and pQCT correlated well with each other as measurements of bone mass, but BMCTB was more discriminating than the other measurements in the diagnosis of osteoporosis.

Absorptiometry, Photon↗

PubMed1997

Characterization of presynaptic proteins involved in synaptic vesicle exocytosis in the nervous system of Torpedo marmorata.

Synaptobrevin, SNAP-25 and syntaxin (SNAP receptor proteins) are molecular components that play a key role in the exocytotic machinery of synaptic vesicles. Their presence, distribution and interactions are reported in central and peripheral nervous systems of the electric fish Torpedo marmorata. These three proteins form a protein complex in all the nervous system regions tested, including the electric lobe and the electric organ which is innervated by pure cholinergic nerve terminals. Immunoblot analysis revealed a double protein pattern of SNAP-25 in the anterior brain and cerebellum, although a single protein band corresponding to SNAP-25 was observed in the electromotor system. Moreover, SNAP-25 showed a differential distribution in the electromotor system. It was present along nerve fibres and terminals that innervated the electric organ but it was not detected in nerve terminals at the electric lobe. Immunoisolation experiments using anti-synaptobrevin antibodies showed a tissue-specific co-existence of SNAP-25 and syntaxin with synaptobrevin in the immunoisolated organelles. In conclusion, the molecular components of the exocytotic machinery are shown to be conserved in Torpedo, although some differences mainly on SNAP-25, suggest a potential diversity in the regulation of neurosecretion.

Animals↗

PubMed1997

Ultrasound bone velocity on proximal phalanges in premenopausal, perimenopausal, and postmenopausal healthy women.

RATIONALE AND OBJECTIVES: The authors studied premenopausal, perimenopausal, and postmenopausal women to determine if ultrasound bone velocity (UBV) on proximal phalanges of women reflect bone changes related to gonadal status and age. METHODS: A total of 166 healthy women-64 postmenopausal women (mean age 58.7 +/- 9.4 years), 41 perimenopausal women (mean age 49.5 +/- 2.9 years), and 61 premenopausal women (mean age 36.8 +/- 7.1 years)-were studied. All the women underwent UBV study of the 2nd to 5th proximal phalanges on the nondominant hand and the mean value of all ultrasound measurements was calculated. RESULTS: The postmenopausal women had a UBV that differed significantly, one-way analysis of variance, from that of the perimenopausal women and premenopausal women (both P < 0.001). The UBV measurements of the perimenopausal women differed significantly from those of the premenopausal women (P < 0.01). Simple linear regression analysis of the relation between UBV and age showed that this was significant and negative in the overall group of women (r = -0.69; P < 0.0001), significant in the perimenopausal (r = -0.66; P < 0.001) and postmenopausal women (r = -0.69; P < 0.001) and nonsignificant in the premenopausal women (r = 0.08; P not significant). In the postmenopausal women, the correlation between UBV and years since menopause was larger (r = -0.71; P < 0.0001) than the correlation between UBV and chronological age. CONCLUSIONS: Ultrasound bone velocity of the phalanx, as a method for measuring changes in bone with age, has a precision that makes it possible to detect changes in bone mass in perimenopausal women and may perform similarly to other bone mass measurements.

Adult↗

PubMed1997

Influence of soft tissue (fat and fat-free mass) on ultrasound bone velocity: an in vivo study.

RATIONALE AND OBJECTIVES: The authors determine the relative effect of soft-tissue compartments, body fat (percent [%Bfat] and weight [Bfat kg]) and fat-free mass (FFM kg), on measurements of ultrasound bone velocity (UBV m/second). METHODS: The authors measured UBV in proximal phalanxes and body fat and fat-free mass by near infrared interactance in 40 healthy premenopausal women (mean age +/- standard deviation 28.2 +/- 3.8 years). RESULTS: Correlation study (Fisher's r to z) showed that UBV correlated negatively with %Bfat (r = -0.61, P < 0.0001), Bfat kg (r = -0.56, P = 0.0001) and marginally with body weight (r = -0.33, P = 0.0403), but did not correlate with FFM kg or H2O L (both r = -0.08, P not significant). When the correlation test was adjusted for weight and age (partial correlation), the negative correlation between UBV and %Bfat persisted (r = -0.54, P < 0.0005; and r = -0.63, P < 0.0001, respectively) and the correlation with FFM kg, adjusted for weight, became positive and significant (r = 0.55, P < 0.0005). CONCLUSIONS: These results, to our knowledge, are the first to be obtained by in vivo evaluation of UBV in relation to body fat and fat-free mass. Body fat, but not fat-free mass, was the main factor affecting UBV. This confirms the deficiency of UBV measurements, considering that obesity is a protective factor for bone mass.

Adipose Tissue↗

PubMed1997

Comparison of digital rectal examination, transrectal ultrasonography, and multicoil magnetic resonance imaging for preoperative evaluation of prostate cancer.

OBJECTIVE: A prospective study was designed to compare the potentials of digital rectal examination (DRE), transrectal ultrasound (TRUS), and magnetic resonance imaging (MRI) using integrated endorectal and pelvic phased-array coils for preoperative estimation of tumor volume and local extent of prostate cancer. METHODS: Evaluation of 20 consecutive patients undergoing radical retropubic prostatectomy included DRE, TRUS with a 7.5-MHz transducer, and MRI on a 1.5-tesla GE Signa system. Step sections (5 mm) of the entire specimen were performed, and tumor volume and percentage of gland involved were calculated. RESULTS: DRE, TRUS, and endorectal and pelvic phased-array MRI showed 50, 75, and 95% of the cancers, respectively. There was a linear correlation on MRI between predicted tumor volume and pathological tumor volume (r = 0.82, p < 0.0001), but not between predicted volume on DRE or TRUS and real volume. The accuracy for detecting extracapsular penetration was 60% for DRE and TRUS and 79% for MRI. The accuracy for detecting seminal vesicle invasion was 60% for DRE, 66 for TRUS, and 89% for MRI. The negative predictive value for extracapsular and seminal vesicle extension was highest for MRI (85 and 93%, respectively). The accuracy for tumor location in the apex of the prostate was 30% for DRE, 47 for TRUS, and 89% for MRI. CONCLUSIONS: MRI with integrated endorectal and pelvic phased-array coils satisfactorily predicted tumor volume and tumor extent preoperatively. Multicoil MRI can assist in decision making as it is valuable in the definition of patients that may benefit from surgery and can be of help for evaluating the risk of a positive margin, especially in the apical resection.

Aged↗

PubMed1996

Bone mass in Parkinson's disease: a study with three methods.

Recent reports suggest the presence of osteopenia in a high percentage of patients with Parkinson's disease (PD). These data contrast with previous reports of our group, perhaps due to the different methods used. We studied bone mass in 52 PD patients (28 males, 24 females) and in 80 age- and sex-matched controls (40 males, 40 females) who had no other disease that could affect bone mass. We measured the totally body bone mineral content (TBBMC) and the ultrasound bone velocity (UBV) of transmission in phalanx, and performed metacarpal radiogrammetry with computerized radiography (CCT). We also measured serum levels of total alkaline phosphatase and tartrate-resistant acid phosphatase, which were significantly increased in PD patients compared with controls (P < 0.0001). TBBMC was significantly lower in males (P < 0.05) and females (P < 0.05) with PD with respect to their controls. CCT did not differ significantly between the study groups. UBV was significantly lower in males with PD (P < 0.005), but similar in female PD and controls. These data suggest that the changes reported in bone mass in PD patients can depend on the sex and the study methods. We only found severe osteopenia in one male (3.6%) and five females (20.8%) with PD according to z-score. Only in women was no relationship found between TBBMC and severity of PD.

Absorptiometry, Photon↗

PubMed1996

Behavior of bone mass measurements. Dual energy x-ray absorptiometry total body bone mineral content, ultrasound bone velocity, and computed metacarpal radiogrammetry, with age, gonadal status, and weight in healthy women.

RATIONALE AND OBJECTIVES: Bone mass as measured by dual energy x-ray absorptiometry varies with body weight. The authors studied the behavior of bone mass measurements made by ultrasound bone velocity and metacarpal radiogrammetry in relation to body weight. METHODS: Eighty healthy women were studied: 40 post-menopausal and 40 premenopausal (mean age 60 +/- 6 and 38 +/- 8 years, respectively). The authors performed in every subject the following studies: a radiograph of the nondominant hand for metacarpal cortical thickness, a study of the 2nd to 5th proximal phalanges for ultrasound bone velocity, and total bone mineral content by dual energy x-ray absorptiometry. RESULTS: The measurements obtained with the three methods correlated significantly with each other (P < 0.0001). The only parameter related significantly with weight were total bone mineral content (P < 0.0001). In the premenopausal women, age did not correlate with any measurement. In the postmenopausal women, age correlated significantly with the three measured parameters (P < 0.0058 to P < 0.0001). CONCLUSIONS: Weight did not influence ultrasound bone velocity and metacarpal cortical thickness measurements.

Absorptiometry, Photon↗

PubMed1996

Differential distribution of syntaxin isoforms 1A and 1B in the rat central nervous system.

Syntaxin 1 binds to several proteins of the synaptic terminal and is a central component in the pathway of protein-protein interactions that underlies docking and fusion of synaptic vesicles. Molecular studies revealed the occurrence of two isoforms, syntaxin 1A and syntaxin 1B, which coexpress in neural tissues. However, they display differential expression patterns in endocrine cell types. We generated isoform-specific antibodies that were used in Western blotting and immunocytochemical studies. First, we confirmed the sole presence of syntaxin 1A in endocrine pituitary cells. Second, we found distinctive immunolabelling patterns of each isoform in the rat olfactory system, hippocampus, striatum, thalamus and spinal cord. In addition, the principal white matter commissures displayed distinct immunoreactivity for each isoform. This report shows, for the first time, major differences between the distributions of syntaxin 1A and syntaxin 1B isoforms in the rat central nervous system.

Animals↗

PubMed1996

Expression of synaptosomal-associated protein SNAP-25 in endocrine anterior pituitary cells.

A growing body of evidence indicates that the fundamental molecular mechanism of exocytosis in the secretory pathway may be structurally similar in all eukaryotic cells. The synaptosomal-associated protein of 25 kDa (SNAP-25) is a plasma membrane protein involved in regulated exocytosis in neurons. In order to compare exocytotic components in neurons and endocrine cells, we have analyzed the expression of SNAP-25 in the rat anterior pituitary. Western blotting analysis documented the presence of SNAP-25 in anterior pituitary homogenates and cultured anterior pituitary cells. In addition to SNAP-25, other neuronal proteins involved in exocytosis (syntaxin, VAMP/synaptobrevin and Rab3A) were also detected in the anterior pituitary. The specific expression of SNAP-25 mRNA in anterior pituitary cells was also corroborated by Northern analysis. SNAP-25 immunoreactivity was located at the plasma membrane of endocrine anterior pituitary cells. Characteristically, patches of fine punctate deposits exhibited intense SNAP-25 immunoreactivity. Double-labeling immunocytochemistry revealed that SNAP-25 was mainly associated with gonadotroph cell populations. Furthermore, we demonstrate that in the anterior pituitary, SNAP-25 is selectively cleaved by clostridial neurotoxins. In conclusion, our results establish the presence of SNAP-25 in secretory anterior pituitary cells and suggest a potential role of this protein in the secretion of adenohypophysial hormone.

Animals↗

PubMed1995

Cloning characterization and expression of the cDNA encoding a neuron-specific alpha-tubulin isoform highly represented in the electric lobe of Torpedo marmorata.

A cDNA (alpha T6) encoding an alpha-tubulin from Torpedo marmorata (Tm) was isolated and sequenced. The deduced 451-amino-acid (aa) sequence codes for an alpha-tubulin of 50,161 Da. The aa sequence of alpha T6 of Tm showed a 70-99.6% identity to the other alpha-tubulins previously described. Moreover, the alpha T6 aa sequence was 95-99.6% identical to neural-specific tubulins of mouse, rat, human and siberian salmon. The corresponding mRNA is highly represented in the giant motoneurons of the electric lobe. All neuronal populations of the Tm brain exhibit variable levels of alpha T6 expression, with the highest levels in the long-axon-projecting neurons. These results suggest that this alpha-tubulin isoform may play an important role in the maintenance and/or remodeling of the neuronal cytoskeleton.

Amino Acid Sequence↗

PubMed1995

Effects of prolonged social isolation on responses of neurons in the bed nucleus of the stria terminalis, preoptic area, and hypothalamic paraventricular nucleus to stimulation of the medial amygdala.

The studies presented demonstrate changes in hypothalamo-pituitary-adrenocortical secretion, and in electrical activity and synaptic responses of neurons in the bed nucleus of the stria terminalis, preoptic area, and hypothalamic paraventricular nucleus of rats exposed to early, long-term social isolation. Rats isolated from all social contact from an early preweaning time showed reduced basal plasma corticosterone concentrations, compared with littermate controls raised under social conditions. Isolated animals also exhibited a selective decrease in the spontaneous electrical activity of neurons within the hypothalamic paraventricular nucleus and lateral preoptic area, but not in adjacent structures. Moreover, isolation also altered the response of neurons in certain nuclei to electrical stimulation of the medial amygdala. Thus, a reduction in excitatory responses, and an increase in inhibition and nonresponsiveness, of preoptic area and paraventricular nucleus neurons was recorded, compared with control rats. Neurons in the bed nucleus of the stria terminalis were less affected, but showed an increase in the duration of excitatory responses following medial amygdala stimulation. These results, obtained from urethane-anesthetized rats, together with the reduced basal plasma corticosterone concentrations, suggest a reduction in limbic-hypothalamo-pituitary-adrenocortical (LHPA) activity following maternal deprivation and prolonged social isolation. This may result from altered limbic activity, specifically in the amygdala and its pathways to the paraventricular nucleus (PVN). Such alterations may include the stria terminalis, in so much as increased efficacy of inhibitory components and reduced efficacy of excitatory components was observed. The neural mechanisms underlying these alterations could involve an altered synaptology of the regions examined and/or a disruption of glucocorticoid feedback events.

Amygdala↗

PubMed1995

Adrenalectomy alters the response of neurons in the bed nucleus of the stria terminalis to electrical stimulation of the medial amygdala.

This study was performed to characterize the effects of adrenalectomy (ADX) on electrical activity and synaptic responses of bed nucleus of the stria terminalis (BNST) and preoptic area (POA) neurons, which are involved in the control of limbic-hypothalamo-pituitary-adrenocortical (LHPA) activity. Adrenalectomy altered the response of BNST neurons to medial amygdala (AME) stimulation, increasing the proportion of excitatory responses and reducing the number of cells inhibited. No such effects were found for neurons within the POA. The basal activity of neurons recorded within the BNST and POA, as well as the latencies and duration of responses, was not affected. The specificity of the effects upon BNST, but not POA, neurons suggests that the response of BNST neurons to AME stimulation is corticosteroid dependent, whereas the response of preoptic neurons is not.

Adrenalectomy↗

PubMed1994

Insulin-like growth factor I-immunoreactive peptide in adult human cerebellar Purkinje cells: co-localization with low-affinity nerve growth factor receptor.

It has been proposed that Insulin-like growth factor I is involved in the development, growth and maintenance of the central nervous system possibly interacting with other trophic factors. High levels of insulin-like growth factor I have been detected in the cerebellum during development and adulthood suggesting a specific role for insulin-like growth factor I in this brain area. While there is ever increasing data regarding the cell types containing endogenous insulin-like growth factor I in the rat brain, no information on the human brain is yet available. In the present study we sought to analyse the precise location of insulin-like growth factor I peptide in the adult human cerebellum using a specific antiserum against recombinant human insulin-like growth factor I. After immunocytochemistry, numerous Purkinje cells exhibited intense positive staining occupying the cell soma, dendrites and dendritic spines as well as axons. Occasionally, immunoreactive Purkinje cell axons were arciform and exhibited bulbous dilatations along their proximal length. Putative recurrent collaterals of Purkinje cell axons were also insulin-like growth factor I reactive. Double-staining immunocytochemistry in the same sections consistently showed, as expected, co-expression of insulin-like growth factor I and calbindin, although a few calbindin containing Purkinje cells lacked insulin-like growth factor I immunostaining suggesting there are insulin-like growth factor I positive Purkinje cell subsets in the human cerebellum. In addition, co-expression of insulin-like growth factor I and low-affinity nerve growth factor receptor-immunoreactive protein was found in a subpopulation of insulin-like growth factor I positive Purkinje cells. The results of this study prove the presence of insulin-like growth factor I immunoreactivity in a Purkinje cell subpopulation of the adult human cerebellum suggesting that insulin-like growth factor I may participate in paracrine or autocrine regulatory systems in the adult human brain.

Adult↗

PubMed1994

Interactions between serotonin, thyrotropin-releasing hormone, and substance P in the CNS regulation of adrenocortical secretion.

Double-labeling immunohistochemical studies were performed to discern the morphological relationships between corticotropin-releasing factor-immunoreactive (CRF-ir) perikarya and afferent innervation in the hypothalamic paraventricular nucleus (PVN) of the rat. Attention was focussed on the local innervation by serotonin (5-hydroxytryptamine, 5-HT), thyrotropin-releasing hormone (TRH) and substance P (SP)-ir nerve terminal fibers. 5-HT-ir and SP-ir fibers were present in moderate numbers, in close apposition with CRF-ir perikarya. Sparse TRH-ir fibers were observed, but a population of TRH-ir perikarya was found in proximity with the CRF-ir cell bodies. TRH-ir perikarya in the PVN were surrounded by both 5-HT- and SP-ir fibers. Neuroendocrine studies were performed to investigate the interactions between 5-HT, TRH and SP in the regulation of hypothalamo-pituitary-adrenocortical (HPA) secretion. Male rats were prepared bearing cannulae for intracerebroventricular (ICV) or intra-PVN administration of drugs. 5-HT, at all doses tested (0.1, 40, or 80 nmol, ICV), caused increases in plasma corticosterone (CS) concentrations in tail-vein blood collected 20 min after injection. ICV injections of TRH caused dose-dependent increases in plasma CS, but did not further increase HPA responses when injected together with 5-HT. SP alone had little effect, although a significant reduction in plasma CS concentrations was observed in several individual experiments. However, SP (0.1 nmol) significantly attenuated CS responses following high doses of 5-HT (40 and 80 nmol, ICV), although the response to 0.1 nmol 5-HT was not affected. Combined injection of SP with TRH resulted in HPA responses not different from those following TRH alone. Similarly, SP did not reduce the HPA response observed with TRH and 40 nmol 5-HT in combination. Intra-PVN injections of 5-HT (0.1 or 40 nmol) and TRH also increased plasma CS concentrations. Intra-PVN injections of SP had little effect on plasma CS concentrations although a tendency toward a decrease in plasma CS was observed, as with the ICV injections. Combined intra-PVN injection of 5-HT (0.1 nmol) with TRH (0.1 nmol) did not significantly alter the response compared with that observed following TRH alone, although plasma CS concentrations were greater than with 0.1 nmol 5-HT. Combined intra-PVN injections of SP (0.1 nmol) with 5-HT (0.1 nmol) resulted in a significant decrease in plasma CS concentration compared with that following 5-HT alone, but SP did not prevent the CS response to a higher dose of 5-HT (40 nmol).(ABSTRACT TRUNCATED AT 400 WORDS)

Adrenal Cortex↗

PubMed1994

Analysis of vasoactive intestinal peptide receptors and the G protein regulation of adenylyl cyclase in seminal vesicle membranes from streptozotocin-diabetic rats.

The present report describes the status of the vasoactive intestinal peptide (VIP) receptor/effector system of signal transduction in seminal vesicle from streptozotocin (STZ)-treated rats. STZ-treatment modified the binding parameters of the high-affinity sites for VIP in seminal vesicle: 0.78 +/- 0.10 and 2.54 +/- 0.30 nM for the dissociation constant (Kd) in control and diabetic rats, respectively; 0.07 +/- 0.01 and 0.15 +/- 0.03 pmol VIP/mg protein for the maximum binding capacity (Bmax) in control and diabetic rats, respectively. It was associated with a reduced potency of VIP on the stimulation of adenylyl cyclase activity in the diabetic state (ED50 = 64.0 +/- 20.0 nM) as compared to control (ED50 = 9.5 +/- 4.3 nM). In contrast, the stimulatory effects of GTP, Gpp[NH]p and forskolin on the enzyme activity were not modified in diabetic rats. The levels of G-protein subunits in rat seminal vesicle were studied by immunoblot of alpha s and alpha i subunits: whereas alpha i-subunit levels did not vary, those corresponding to alpha s subunit decreased after STZ treatment. In diabetic rats, low concentrations of Gpp[NH]p failed to inhibit forskolin-stimulated adenylyl cyclase activity, suggesting the absence of functional Gi in this condition. In conclusion, present results show a decrease in the sensitivity of the VIP receptor/effector system in seminal vesicle membranes from STZ-treated rats suggesting a physiopathological role for VIP in the seminal neuropathy observed in diabetes.

Adenylyl Cyclases↗

PubMed1994

Ultrasound bone velocity and metacarpal radiogrametry in hemodialyzed patients.

Bone density measurements based on the rate of propagation of ultrasound waves provide information on bone elasticity, which is largely dependent on cortical bone structure. Both bone density and cortical bone present variations dependent on age and sex. As far as we know, bone elasticity in patients on hemodialysis has not been studied, so we used ultrasound bone velocity and metacarpal radiogrametry to study 23 adult patients with end-stage renal disease. The patients' results were compared with those of a group of 23 healthy subjects matched by age and sex. The measurements obtained by both ultrasound bone velocity and metacarpal radiogrametry were lower in hemodialyzed patients (p < 0.025) than in controls and there was a good correlation between the two measurements (r2 = 0.561; p < 0.0007). Neither of the measurements correlated with age or time on dialysis. These results show that bone elasticity in dialyzed patients is diminished, which could be an important factor in the bone lesions of these patients.

Adult↗