A Model of Bone Adaptation Using a Global Optimisation Criterion Based on the Trajectorial Theory of Wolff

Julius Wolff originally proposed that trabecular bone was influenced by mechanical stresses during the formative processes of growth and repair such that trabeculae were required to intersect at right angles. In this work, we have developed an analytical parametric microstructural model, which captures this restriction. Using homogenisation theory, a global material model was obtained. An optimal structure constructed of the homogenised material could then be found by optimising a cost function accounting for both the structural stiffness and the biological cost associated with metabolic maintenance of the bone tissue. The formulation was applied to an example problem of the proximal femur. Optimal densities and orientations were obtained for single load cases. The situation of multiple loads was also considered. In this case, we observe that the alignment of principal strains with the material orthotropy direction is, in general, not possible for all load cases. Thus less restrictive microstructures (nonorthotropic) will yield higher structural stiffnesses than strictly orthotropic microstructures.

Use of danaparoid sodium (Orgaran) as an alternative to heparin sodium during cardiopulmonary bypass: a clinical evaluation of six cases

Heparin-induced thrombocytopenia (HIT) has become more prevalent in today's cardiac setting and has resulted in the need for alternative anticoagulant therapies. Danaparoid sodium, one alternative to heparin, has been used in six cardiopulmonary bypass procedures in this hospital. This clinical experience has resulted in the progressive refinement of a protocol for the 'safe' clinical use of danaparoid sodium. Although there were six positive outcomes with the use of danaparoid sodium, alternatives must be explored in order to find the optimal anticoagulant for the treatment of HIT.

Gelastic epilepsy possibly following antirabies vaccine

A case of child with gelastic epilepsy following administration of antirabies vaccine is presented. No associated structural brain could be identified in the patient. Possibility of relationship between antirables vaccine and gelastic epilepsy is discussed.

Synchronization of ovulation in crossbred dairy heifers using gonadotrophin-releasing hormone agonist, prostaglandin F2alpha and human chorionic gonadotrophin or estradiol benzoate

Girolando (Gir x Holstein) is a very common dairy breed in Brazil because it combines the rusticity of Gir (Bos indicus) with the high milk yield of Holstein (Bos taurus). The ovarian follicular dynamics and hormonal treatments for synchronization of ovulation and timed artificial insemination were studied in Girolando heifers. The injection of a gonadotrophin-releasing hormone (GnRH) agonist was followed 6 or 7 days (d) later by prostaglandin F2alpha (PGF2alpha). Twenty-four hours after PGF2alpha injection either human chorionic gonadotropin (hCG, GPh-d6 and GPh-d7 groups) or estradiol benzoate (EB, GPE-d6 and GPE-d7 groups) was administered to synchronize ovulation and consequently allow timed artificial insemination (AI) 24 and 30 h after hCG and EB injection, respectively. Follicular dynamics in Girolando heifers was characterized by the predominance of three follicular waves (71.4%) with sizes of dominant follicles (10-13 mm) and corpus luteum (approximately 20 mm) similar to those for Bos indicus cattle. In the GnRH-PGF-hCG protocol, hCG administration induced earlier ovulation (67.4 h, P<0.01) compared to the control group (GnRH-PGF) and a better synchronization of ovulation, since most of it occurred within a period of 12 to 17 h. Pregnancy rate after timed AI was 42.8 (3/7, GPh-d6) to 50% (7/14, GPh-d7). In contrast, estradiol benzoate (GnRH-PGF-EB protocol) synchronized ovulation of only 5 of 11 heifers from the GPE-d7 group and of none (0/7) from the GPE-d6 group, which led to low pregnancy rates after timed AI (27.3 and 0%, respectively). However, since a small number of Girolando heifers was used to determine pregnancy rates in the present study, pregnancy rates should be confirmed with a larger number of animals.

Distribution of vasoactive intestinal peptide and calcitonin gene-related peptide immunoreactive nerve fibers and binding sites in the hamster seminal vesicle during post-natal development

The distribution of vasoactive intestinal peptide (VIP)- and calcitonin gene-related peptide (CGRP)-immunoreactive nerves and 125I-labeled VIP- and CGRP-binding sites was studied in the hamster seminal vesicle of 12-, 30- and 60-day-old animals. In addition, the general innervation of the seminal vesicle was examined using the general neuronal marker synaptophysin. Our results show that the densities of the overall (synaptophysin immunoreactive) and CGRP-immunoreactive innervation is constant during the post-natal development of the gland. However, a significant decrease in VIP-containing nerves is observed at the end of puberty. The autoradiographic study revealed that in 12-day-old animals, the epithelium presents VIP binding sites. However, in 30-day-old animals, VIP binding sites are observed in the epithelium of only a few clumps of acini. In 60-day-old animals, the gland is composed of acini with dilated lumina where VIP binding sites are not detected. In all groups studied the epithelium does not exhibit CGRP binding sites. The seminal vesicle muscle layer displays specific binding sites for both VIP and CGRP at all post-natal developmental times, but the density of VIP binding sites is higher in 12- than in 30- and 60-day-old animals. Our results, showing the presence of specific VIP and CGRP binding sites during the development of the hamster seminal vesicle, suggest that these neuropeptides may be involved in the growth and differentiation of the gland.

[Cardiac neuronal depopulation in hamsters (Mesocricetus auratus) chronically infected with Trypanosoma cruzi]

The aim of this study was to obtain an experimental animal model of destruction of cardiac neurons in order to investigate the behavior of the cardiac nervous system of hamsters chronically infected with Trypanosoma cruzi. We counted the neuronal cells of the cardiac autonomic nervous plexus in hamsters inoculated with 35,000 blood forms of three different T. cruzi strains and killed 5, 8 and 10 months after infection. We showed for the first time severe neuronal destruction in an experimental animal model with characteristics similar to those observed in human Chagas'disease.

Health anxiety and characteristics of self-initiated general practitioner consultations

Health anxiety has been hypothesized to lead to a cycle of repeated medical consultations. We investigated the relationship of health anxiety to patients' frequency of general practitioner visits, and to their expectations about the index visit in 200 general practice attenders. Health anxiety scores declined modestly with age, and were similar in men and women. Frequency of visits rose from 2.6 per year in the lowest decile of health anxiety to 4.2 in the highest (p=0.033). Across the same range, the odds of seeking advice prior to visiting the doctor rose from 0.25 to 0.56 (p=0.034), and the odds of believing that a specialist referral would be needed rose from 0.22 to 0.48 (p =0.008). There was no association between health anxiety and previous referral for investigation of symptoms that had not resulted in a medical diagnosis, nor with attitudes to prescriptions, possibly because there was little variation in either. In this population, absolute levels of health anxiety were low. Nevertheless, within this "normal" range, there was an association between level of health anxiety and frequency of visiting, and with expectations for the index visit. The findings support the health anxiety model as predicting use of services by psychologically normal persons.

[The Maffucci syndrome with axial bone lesions. A rare cause of low back pain]

The authors describe the case of a twenty-nine-year-old female with the diagnosis of Maffucci's syndrome, since the age of five, with lower back and lower limb pain. The diagnosis was made of bone axial lesions, which are seldom found in this syndrome. Sarcomatous transformation was found in one of them.

Molecular genetic analysis of a human neuropeptide Y receptor. The human homolog of the murine "Y5" receptor may be a pseudogene

Neuropeptide Y is a 36-amino-acid peptide amide with numerous biological activities. These functions are mediated through several pharmacologically distinct receptors. To date five receptor subtypes have been cloned. Here we report the isolation, by low stringency homology cloning from a hypothalamic library, of a cDNA encoding the human homolog of the murine neuropeptide Y receptor subsequently reported (). Translation of the human Y1-like receptor clone suggested that it encoded a receptor which is truncated in the third extracellular loop. Comparison of the human Y1-like sequence to that of the human Y1 receptor suggested that the truncated receptor could have resulted from a frameshift due to a single nucleotide deletion in the sixth transmembrane domain. Southern blot analysis suggested that the gene is single copy in the human genome. The gene is located on chromosome 5q. To test the hypothesis that allelic variation of nucleic acid length within the sixth transmembrane domain of the Y1-like receptor may exist to produce a functional receptor, genomic DNA from 192 individuals of various ages, ethnic backgrounds, and degrees of obesity were analyzed electrophoretically and by direct sequencing. No variation was detected in any of the subjects, indicating that this receptor subtype may be a transcribed pseudogene in humans.

Effect of castration on the VIPergic innervation and 125I-labelled vasoactive intestinal peptide (VIP) binding sites in the hamster seminal vesicle. A quantitative immunohistochemical and receptor autoradiographic study

In the present work we have investigated the effects of medium- (15 days) and long-term (2 months) castration on vasoactive intestinal peptide (VIP)-immunoreactive nerve fibres and 125I-labelled VIP binding sites in the adult hamster seminal vesicle. The density of VIP- and synaptophysin (general neuronal marker)-containing nerve fibres was determined in immunofluorescently stained cryostat sections using a computerised image analysis system. The morphological analysis of 125I-VIP binding sites in seminal vesicle cryostat sections was performed by quantitative receptor autoradiography. Our results show that the densities of the overall (synaptophysin immunoreactive) and VIPergic innervation increase in both medium and long-term castrated animals. In absolute terms, the quantity of VIP- and synaptophysin- containing nerves is not altered in medium-term castrates, but decreases for synaptophysin in long-term castrates. Medium-term castration does not affect the density of 125I-VIP binding sites in the gland muscular coat, but a significant decrease is observed after long-term castration. In conclusion, our results indicate that whereas VIP nerves are apparently unaffected by castration, 125I-VIP binding sites in the muscular coat of hamster seminal vesicle are sensitive to androgen levels.

Familial reverse seasonal affective disorder - a case report

A patient with recurrent summer depression for seven consecutive years is described, whose mood significantly worsened with increased environmental temperature. She had a family history of recurrent summer depression in both her brother and paternal grandmother with symptoms similar to those of typical endogenous depression. The patient's mood switched to hypomania with antidepressant therapy.

Calcitonin gene-related peptide in the hamster seminal vesicle and coagulating gland: an immunohistochemical, autoradiographical, and pharmacological study

The distribution of calcitonin gene-related peptide (CGRP)-immunoreactive nerves and CGRP binding sites, as well as the effect of CGRP on the muscle tension, was studied in the hamster seminal vesicle and coagulating gland. The use of an immunofluorescence staining technique on cryostat sections revealed that in the hamster seminal vesicle and coagulating gland, CGRP-positive nerve fibers are found in the connective interstitium and in the muscular and mucosal layers. Using an in vitro receptor autoradiographic technique, CGRP binding sites were found associated with the muscular coat. CGRP (10 pM to 1 microM) relaxed the seminal vesicle and the coagulating gland precontracted by either noradrenaline (10-30 microM) or the alpha 1-agonist, phenylephrine (10 microM). In preparations contracted by carbachol (10 microM), CGRP relaxed the seminal vesicle but not the coagulating gland. In both preparations, CGRP (1 microM) did not affect the muscle resting tension. These results suggest that CGRP may act as an inhibitory modulator of the autonomic control of contractility in the male accessory sex glands of the hamster.

Cloning and functional expression of a cDNA encoding a human type 2 neuropeptide Y receptor

Neuropeptide Y (NPY) is a 36-amino acid polypeptide that is widely distributed in the central nervous system and periphery. Pharmacological studies have suggested that there are at least three receptor subtypes, Y1, Y2, and Y3. Cloning of the Y1 subtype has been reported previously. Here we report the isolation by expression cloning of a cDNA encoding a human NPY receptor displaying a pharmacology typical of a Y2 receptor. COS-7 cells transfected with the cDNA express high affinity binding sites for NPY, peptide YY, and NPY13-36, whereas [Leu31,Pro34]NPY binds with lower affinity. The receptor is 381 amino acids in length and has seven putative transmembrane regions typical of G-protein-coupled receptors. Comparison of the amino acid sequence of this Y2 receptor to that of the human Y1 receptor indicates that the two receptors are 31% identical at the amino acid level. Northern blot analyses reveal a single 4-kilobase mRNA species and indicate that the messenger RNA is present in many areas of the central nervous system. NPY induced calcium mobilization and inhibited forskolin-stimulated cAMP accumulation in Chinese hamster ovary cells that stably express the Y2 receptor cDNA, indicating that the recombinant Y2 receptor is functionally coupled to second messenger systems.

Bacillaene, a novel inhibitor of procaryotic protein synthesis produced by Bacillus subtilis: production, taxonomy, isolation, physico-chemical characterization and biological activity

Bacillaene, a novel polyene antibiotic, was discovered and isolated from fermentation broths of a strain of Bacillus subtilis. The novel antibiotic has a nominal molecular weight of 580 and an empirical formula of C35H48O7. Bacillaene is active against a broad spectrum of bacteria in agar-plate diffusion assays. Studies in vitro indicate that the antibiotic inhibits prokaryotic protein synthesis but not eukaryotic protein synthesis. Cell survival studies performed with strains of Escherichia coli indicate that the antibiotic is a bacteriostatic agent.

[The ambulatory recording of the long-term electrocardiogram]

In the past 5 years, a new approach was developed to evaluate the patient with sporadic symptoms as is the patient with syncope--the long-term ambulatory loop electrocardiogram monitoring. This method allow to assure the heart rate and rhythm at the moment of the symptoms hardly to be able with the other diagnostic tools disposable. The long-term ambulatory loop electrocardiogram monitoring was not to replace the actual tools, but complement them. Newer devices are smaller and too light, and have the ability of registry some minutes before and after the symptom. In the near future, the devices will be able to detected and store arrhythmias and to possess an easy and accessible management. With continued and profitable work that has been done in this area, a large proportion of patients with the diagnosis of "syncope of unknown etiology" can have a diagnostic and specify therapeutic and we will be able to assert with more strictness if the symptoms related by the patient are or not of cardiovascular origin.

ION TRANSPORT IN THE INTESTINE OF ANGUILLA ANGUILLA: GRADIENTS AND TRANSLOCATORS

The transport of Na+, K+ and Cl- across the isolated epithelium of the eel intestine was studied using a combination of four experimental strategies: short-circuiting, measurements of intracellular potentials and ion concentrations, application of a variety of transport inhibitors and measurement of unidirectional fluxes with radioactive tracers. When short-circuited, the system performs a net transport of Cl- and Na+ towards the blood side, with a stoichiometry approaching 2, and a much smaller net transport of K+ towards the lumen. The system is totally driven by the sodium pump located in the basolateral barrier and the main coupling between the fluxes of the three ions is through the operation of a furosemide-sensitive transporter in the apical barrier, probably a 2Cl-/Na+/K+ symporter. The inhibitory effect of DIDS and picrylsulphonic acid on the short-circuit current, when added to the serosal side, suggests the presence of a sodium-dependent anionic shuttle located in the basolateral membrane. The short-circuit current is inhibited by H25, a non-specific inhibitor of the K+/Cl- symport, added to the serosal side. This effect occurs after a delay of at least 5 min and may result from the diffusion of the drug to the apical barrier, where it blocks the 2Cl-/Na+/K+ symport with much higher affinity.

Spectral analysis of heart rate variability in athletes

The objectives of the study were to characterize power spectrum pattern of the heart rate variability and assessment of the relative contributions of sympathetic and parasympathetic cardiac nervous system control in athletes. Thirty-three male athletes, swimming (1), canoeing (10), cycling (6), athletics (4), football (3), roller-skating (2) and volleyball (7) aged 23.4 +/- 5.5 years, with a mean athletic level of 18 hours/week (8-45) and 33 sedentary healthy control subjects were included. Ecg signals were recorded after a period of 15 minutes in supine rest with controlled breathing at 15 cycles/min. Signal acquisition was done at 300 samples/sec. From 512 consecutive heart beats, we calculated mean average, standard deviation, maximum and minimum R-R intervals and, after computing the fast Fourier transform, total spectrum power, low frequency (LF), high frequency (HF) components and its ratio (LF/HF). The average R-R interval was 987.7 +/- 168.8 ms and 762.7 +/- 125.3 ms, the variance was 5.44 and 2.51 ms2 and ratio of R-R interval maximum/minimum (E/I ratio) 1.53 +/- 0.16 and 1.41 +/- 0.16, respectively for athletes and control group. Differences between groups were significant (p < 0.01) for all parameters, with higher variability in the athletes. Both spectral bands (LF and HF) had higher power in athletes (LF = 925 +/- 920 and HF = 2258 +/- 2349 ms2) than in the control group (LF = 442 +/- 446 and HF = 1179 +/- 1542 ms2) (p < 0.01). There were no significant differences for LF/HF ratio, or normalized LF (LF%) or normalized HF (HF%) between groups.(ABSTRACT TRUNCATED AT 250 WORDS)

[Variability of heart rate: a perspective]

The present work is an attempt to provide a general overview on the current methods and applications of heart rate variability (HRV), starting from the underlying mechanisms of cardiac rhythmic automaticity and the influence on heart rate of biological modulators, namely autonomous nervous system. Different evaluation methods for HRV are compared in what concerns the duration of the records under analysis and the mathematical approach (spectral/non-spectral). Finally, clinical applications of HRV are mentioned, some of them the Department is particularly interested in, namely coronary heart disease, heart failure and diabetic neuropathy. The authors conclude, minding some aspects susceptible of discussion in the future of this technique.