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At least 1,171 records · Page 65Linked to original sources
PubMed2006

Extensor hallucis capsularis: frequency and identification on MRI.

BACKGROUND: The extensor hallucis capsularis (EHC) is the most common name given to the accessory tendon sporadically seen medial to the extensor hallucis longus (EHL). We performed cadaver dissections and MRI evaluation to determine the frequency of its occurrence, the pattern of its origin and insertion, and its potential suitability as tendon graft. METHODS: The EHC was examined by dissection in 81 cadaver feet. Physical parameters pertaining to EHC size and location were recorded. MRI was performed on six cadaver legs to determine if the EHC can be identified radiographically. MRI images were evaluated independently by a foot and ankle specialist and a radiologist. RESULTS: The EHC was present in 71 (88%) of the specimens. It originated from the EHL tendon or muscle in 93% and inserted into the first metatarsophalangeal joint capsule in 99% of cases. All EHC tendons were less than or equal to 4 mm in width; only 16% were more than 2 mm wide. Correct prediction of the presence or absence of EHC by MRI varied according to EHC width: two of two in tendons more than 2 mm, five of eight in tendons 1 to 2 mm, and zero of two in tendons 1 mm or less. CONCLUSION: Up to 14% of the population may have an EHC tendon suitable for grafting in reconstructive surgeries, particularly surgeries related to hallux dysfunction. MRI may have a role in the preoperative identification of the EHC.

Cadaver↗
PubMedDate not supplied

Linkage disequilibrium and the genetic distance in livestock populations: the impact of inbreeding.

Genome-wide linkage disequilibrium (LD) is subject to intensive investigation in human and livestock populations since it can potentially reveal aspects of a population history, permit to date them and help in fine-gene mapping. The most commonly used measure of LD between multiallelic loci is the coefficient D'. Data based on D' were recently published in humans, livestock and model animals. However, the properties of this coefficient are not well understood. Its sampling distribution and variance has received recent attention, but its expected behaviour with respect to genetic or physical distance remains unknown. Using stochastic simulations of populations having a finite size, we show that D' fits an exponential function having two parameters of simple biological interpretation: the residual value (rs) towards which D' tends as the genetic distance increases and the distance R at which this value is reached. Properties of this model are evaluated as a function of the inbreeding coefficient (F). It was found that R and rs increase when F increases. The proposed model offers opportunities to better understand the patterns and the origins of LD in different populations and along different chromosomes.

Alleles↗
PubMed2004

Substitution for natural musk in Pien Tze Huang does not affect its hepatoprotective activities.

Previous studies showed that Pien Tze Huang, a Chinese folk medicine well known for its therapeutic activity in treating liver diseases, protected the liver against carbon tetrachloride (CCl4)-induced damage in mice. In the present study, natural musk, one of the important ingredients of Pien Tze Huang, was replaced by a formulated substitute, and the new formulation of Pien Tze Huang was shown to have similar chromatographic patterns to the original Pien Tze Huang in gas chromatography-mass spectrometry and high performance liquid chromatography. When used in treating mice with CCl4- or galactosamine-induced liver damage, both the original and new formulations of Pien Tze Huang were found to be able to suppress to a similar extent both the histopathological changes in the liver and the elevation of serum alanine aminotransferase and aspartate aminotransferase. Necrosis, cellular ballooning, microvesicular steatosis and lymphocytes infiltration were all significantly reduced in the damaged liver. In hepatoma cells, both formulations activated the activator protein 1 (AP1) enhancer sequence, indicating that both of them were able to act through the JNK signal transduction pathway. The results of the present study showed that the substitution for natural musk does not affect the hepatoprotective activities of Pien Tze Huang. It is also postulated that both formulations protect the liver through regulating signal transduction in the cell.

Animals↗
PubMed2005

A theoretical study of hypothalamo-pituitary-adrenocortical axis dynamics.

Does the hypothalamo-pituitary-adrenocortical (HPA) axis itself generate oscillations? The affirmative answer to this question is commonly assumed, because a regular daily rhythm of its hormones is observed. We offer another plausible explanation of the origin of this pattern: HPA just responds to an external pacemaker. A qualitative mathematical model is constructed wherein all the terms in the equations are physicochemically interpretable. Linear stability analysis shows that this system does not generate oscillations. Computer simulation yields oscillations that are the system's response to an external pulsing activator, implying that the observed pattern does not have to be an intrinsic property of this system.

Adrenal Cortex Hormones↗
PubMed1999

Analysis of meiosis in intratesticular germ cells from subjects affected by classic Klinefelter's syndrome.

Azoospermic subjects affected by Klinefelter's syndrome may occasionally show the presence of intratesticular residual foci of spermatogenesis, and the retrieval of mature spermatozoa from the testis may permit fertility and paternity by means of intracytoplasmic sperm injection. Previous studies have demonstrated that these subjects show the presence of an increased incidence of hyperaploid spermatozoa. Here we analyzed, by fluorescence in situ hybridization using specific probes for chromosomes 8, X, and Y, the spermatogenic process and the meiotic progression of 47,XXY germ cells retrieved by fine needle aspiration of the testis in ten azoospermic patients affected by classic Klinefelter's syndrome. All patients had lower testicular volume, higher gonadotropins, and lower testosterone plasma levels compared with control subjects. Cytological analysis of the testicular cells retrieved by fine needle aspiration showed the presence of Sertoli cells only in eight subjects, while germ cells were observed in two patients. In each patient Sertoli cells showed a 47,XXY karyotype, and the same chromosome pattern was observed in spermatogonia and primary spermatocytes of patients presenting a residual spermatogenesis. Secondary spermatocytes, spermatids, and mature spermatozoa showed different sex chromosome patterns, reflecting their origin from 47,XXY spermatogonia. In conclusion, this study demonstrated that, in subjects affected by Klinefelter's syndrome, residual germ cells may be present in the testis and that 47,XXY spermatogonia are able to undergo and complete the spermatogenic process leading to mature spermatozoa. These data further suggest the need to evaluate the sex chromosome status of sperm from patients affected by Klinefelter's syndrome undergoing assisted reproductive techniques.

Adult↗
PubMed2003

Developmental origin of wiring specificity in the olfactory system of Drosophila.

In both insects and mammals, olfactory receptor neurons (ORNs) expressing specific olfactory receptors converge their axons onto specific glomeruli, creating a spatial map in the brain. We have previously shown that second order projection neurons (PNs) in Drosophila are prespecified by lineage and birth order to send their dendrites to one of approximately 50 glomeruli in the antennal lobe. How can a given class of ORN axons match up with a given class of PN dendrites? Here, we examine the cellular and developmental events that lead to this wiring specificity. We find that, before ORN axon arrival, PN dendrites have already created a prototypic map that resembles the adult glomerular map, by virtue of their selective dendritic localization. Positional cues that create this prototypic dendritic map do not appear to be either from the residual larval olfactory system or from glial processes within the antennal lobe. We propose instead that this prototypic map might originate from both patterning information external to the developing antennal lobe and interactions among PN dendrites.

Animals↗
PubMed2004

Cardiac neural crest of the mouse embryo: axial level of origin, migratory pathway and cell autonomy of the splotch (Sp2H) mutant effect.

A sub-population of the neural crest is known to play a crucial role in development of the cardiac outflow tract. Studies in avians have mapped the complete migratory pathways taken by 'cardiac' neural crest cells en route from the neural tube to the developing heart. A cardiac neural crest lineage is also known to exist in mammals, although detailed information on its axial level of origin and migratory pattern are lacking. We used focal cell labelling and orthotopic grafting, followed by whole embryo culture, to determine the spatio-temporal migratory pattern of cardiac neural crest in mouse embryos. Axial levels between the post-otic hindbrain and somite 4 contributed neural crest cells to the heart, with the neural tube opposite somite 2 being the most prolific source. Emigration of cardiac neural crest from the neural tube began at the 7-somite stage, with cells migrating in pathways dorsolateral to the somite, medial to the somite, and between somites. Subsequently, cardiac neural crest cells migrated through the peri-aortic mesenchyme, lateral to the pharynx, through pharyngeal arches 3, 4 and 6, and into the aortic sac. Colonisation of the outflow tract mesenchyme was detected at the 32-somite stage. Embryos homozygous for the Sp2H mutation show delayed onset of cardiac neural crest emigration, although the pathways of subsequent migration resembled wild type. The number of neural crest cells along the cardiac migratory pathway was significantly reduced in Sp2H/Sp2H embryos. To resolve current controversy over the cell autonomy of the splotch cardiac neural crest defect, we performed reciprocal grafts of premigratory neural crest between wild type and splotch embryos. Sp2H/Sp2H cells migrated normally in the +/+ environment, and +/+ cells migrated normally in the Sp2H/Sp2H environment. In contrast, retarded migration along the cardiac route occurred when either Sp2H/+ or Sp2H/Sp2H neural crest cells were grafted into the Sp2H/Sp2H environment. We conclude that the retardation of cardiac neural crest migration in splotch mutant embryos requires the genetic defect in both neural crest cells and their migratory environment.

Animals↗
PubMed2006

Endogenous retrovirus-related sequences provide an alternative transcript of MCJ genes in human tissues and cancer cells.

The MCJ gene is a member of the DNAJ family, and its transcriptional event is controlled by methylation of the CpG island. In our study, we found LTR33 and LTR7 elements provided an alternative transcript within the MCJ gene. To detect different expression patterns between the originally reported MCJ transcript and the LTR-related transcript, we performed a RT-PCR approach using various human tissues and cancer cells. The original MCJ transcript was detected in human tissues and cancer cells, whereas the LTR-related transcript was only revealed in some cancer cells (HCT106, MCF-3, TE-1, Hela, and CCHM). We also performed a PCR analysis to compare the insertion lineage of the LTR elements with the genomic DNAs of primates, indicating that those LTR33 and LTR7 elements of HERV-H have been integrated into the primate genome at different times. Taken together, we suggest that HERV-related elements trigger transcriptome diversification during primate evolution.

Base Sequence↗
PubMed1995

Antigenic and genetic analyses of the hemagglutinin of influenza viruses isolated from pigs in 1993.

Three strains of influenza A virus (H3N2) were isolated from pigs in Hokkaido, Japan in 1993. The hemagglutinin (HA) antigen of the three isolates was related to that of recent H3N2 viruses of human origin. The reactivity patterns of two of the isolates (A/sw/Obihiro/1/93 and A/sw/Obihiro/2/93) with monoclonal antibodies to the hemagglutinin of A/Bangkok/1/79 strain were similar to that of the human H3N2 strain isolated in Hokkaido in 1988, while that of the other one (A/sw/Obihiro/3/93) was similar to human H3N2 strains of 1993. In the phylogenetic analysis based on the nucleotide sequences of the HA1 regions, the HA genes of the two isolates were shown to be closely related to those of human H3N2 viruses isolated between 1986 and 1988. The remaining one isolate was shown to be closely related to those of current human H3N2 viruses. We have also found serological evidence that the A/sw/Obihiro/1/93 virus is circulating extensively in Obihiro swine. It is clear from these findings that pigs were infected with the recent H3N2 influenza virus during the human epidemic and that the virus has been maintained in pigs for at least five years.

Amino Acid Sequence↗
PubMed1978

Bone loss in response to long-term immobilisation.

The histodynamic response to long-term "non-traumatic" immobilisation was studied in young adult Beagle dogs by means of radiomorphometry and histomorphometry, the right forelimb being encased in plaster and the left forelimb serving as a control. The dogs were killed at two, four, six, eight, twelve, sixteen, twenty, twenty-four, thirty-two and forty weeks and the third metacarpal, radius, ulna and humerus removed for analysis of the contributions of the periosteal, haversian and endosteal envelopes to the bone loss at the mid-diaphysis. The bone mass responded to long-term immobilisation in three stages. First there was a rapid initial loss of bone, reaching its maximum (some 16 per cent of original mass) at six weeks, to which all three bone envelopes, to some extent, contributed. A rapid reversal followed, the bone mass approaching the control values between eight and twelve weeks after immobilisation. A second stage of slower but longer lasting bone loss ended twenty-four to thirty-two weeks after immobilisation; the periosteal envelope was the main contributor (80 to 90 per cent of the total loss). The third stage was characterised by maintenance of the bone mass which had been reduced by some 30 to 50 per cent of original values. This pattern was qualitatively similar in all four bones but the distal bones lost more bone than the proximal bones. The extent of resorption surface and the total histologically "active" periosteal envelope increased parallel to the phases of bone loss. The linear mineralisation rate did not differ significantly between the experimental and control sides.

Animals↗
PubMed2002

Mitochondrial DNA diversity in Southeast Asian populations.

In a previous study of Southeast Asian genetic variation, we characterized mitochondrial DNAs (mtDNAs) from six populations through high-resolution restriction fragment length polymorphism (RFLP) analysis. Our analysis revealed that these Southeast Asian populations were genetically similar to each other, suggesting they had a common origin. However, other patterns of population associations also emerged. Haplotypes from a major founding haplogroup in Papua New Guinea were present in Malaysia; the Vietnamese and Malaysian aborigines (Orang Asli) had high frequencies of haplogroup F, which was also seen in most other Southeast Asian populations; and haplogroup B, defined by the Region V 9-base-pair deletion, was present throughout the region. In addition, the Malaysian and Sabah (Borneo) aborigine populations exhibited a number of unique mtDNA clusters that were not observed in other populations. Unfortunately, it has been difficult to compare these patterns of genetic diversity with those shown in subsequent studies of mtDNA variation in Southeast Asian populations because the latter have typically sequenced the first hypervariable segment (HVS-I) of the control region (CR) sequencing rather than used RFLP haplotyping to characterize the mtDNAs present in them. For this reason, we sequenced the HVS-I of Southeast Asian mtDNAs that had previously been subjected to RFLP analysis, and compared the resulting data with published information from other Southeast Asian and Oceanic groups. Our findings reveal broad patterns of mtDNA haplogroup distribution in Southeast Asia that may reflect different population expansion events in this region over the past 50,000-5,000 years.

Asia, Southeastern↗
PubMed1981

A case with glucagonoma syndrome--heterogeneity of glucagon and insulin.

The heterogeneity of glucagon and insulin in plasma and tissue extracts from a 57-year-old female with glucagonoma syndrome with surgically and autopsy verified islet-cell tumors was studied by Bio-Gel P-10 filtration. The preoperative plasma immunoreactive glucagon (IRG) level was 20.2 ng/ml, and plasma glucagon-like immunoreactivity(GLI) 25.8 ng/ml. The column chromatography of the preoperative plasma revealed three or four IRG components and four GLI components. Among these, peak II, the large glucagon immunoreactivity (LGI) peak, considered a candidate for proglucagon, was prominent, along with peak III. The resected metastatic liver tumor contained an enormous amount of IRG and an appreciable amount of immunoreactive insulin (IRI), indicating that the elevated plasma IRG was mainly of tumor origin. The IRG pattern of the tumor tissue extract revealed a small quantity of IRG in peaks I and II, and a large amount in peak III; control pancreatic tissue extract manifested a similar elution pattern. The IRI elution pattern of the tumor tissue extract revealed two major IRI peaks which migrated close to the elution volume of cytochrome C and insulin, respectively. This is a quite different pattern from the control pancreatic tissue extract in which the RI peak was localized in the elution volume of the insulin. We conclude that the present metastatic liver tumor produced not only enormous amounts of glucagon but heterogeneous peptides which contained immunological insulin determinants within their.

Adenoma, Islet Cell↗
PubMed2004

Finasteride in the treatment of alopecia.

Finasteride is a 5alpha-reductase inhibitor approved for the treatment of male pattern hair loss. Originally approved for the treatment of benign prostatic hypertrophy in 1992, its approval was expanded in 1997 to include the treatment of androgenetic alopecia (AGA) in men at a dose of 1 mg/day. Finasteride inhibits 5alpha-reductase, thereby prohibiting the conversion of testosterone to dihydrotestosterone (DHT), which is implicated in the development of hairless in some men. Reduction in DHT results in a significant improvement in subjective and objective assessments of hair growth and density. Finasteride is well-tolerated with a favourable adverse event history. The most common adverse events include reduced libido, decreased ejaculate volume and gynaecomastia.

Alopecia↗
PubMed2005

Sodium and calcium current-mediated pacemaker neurons and respiratory rhythm generation.

The breathing motor pattern in mammals originates in brainstem networks. Whether pacemaker neurons play an obligatory role remains a key unanswered question. We performed whole-cell recordings in the preBotzinger Complex in slice preparations from neonatal rodents and tested for pacemaker activity. We observed persistent Na+ current (I(NaP))-mediated bursting in approximately 5% of inspiratory neurons in postnatal day 0 (P0)-P5 and in P8-P10 slices. I(NaP)-mediated bursting was voltage dependent and blocked by 20 mum riluzole (RIL). We found Ca2+ current (I(Ca))-dependent bursting in 7.5% of inspiratory neurons in P8-P10 slices, but in P0-P5 slices these cells were exceedingly rare (0.6%). This bursting was voltage independent and blocked by 100 microm Cd2+ or flufenamic acid (FFA) (10-200 microm), which suggests that a Ca2+-activated inward cationic current (I(CAN)) underlies burst generation. These data substantiate our observation that P0-P5 slices exposed to RIL contain few (if any) pacemaker neurons, yet maintain respiratory rhythm. We also show that 20 nm TTX or coapplication of 20 microm RIL + FFA (100-200 microm) stops the respiratory rhythm, but that adding 2 mum substance P restarts it. We conclude that I(NaP) and I(CAN) enhance neuronal excitability and promote rhythmogenesis, even if their magnitude is insufficient to support bursting-pacemaker activity in individual neurons. When I(NaP) and I(CAN) are removed pharmacologically, the rhythm can be maintained by boosting neural excitability, which is inconsistent with a pacemaker-essential mechanism of respiratory rhythmogenesis by the preBotzinger complex.

Animals↗
PubMed2003

Vascularisation of the cerebellar nuclei in Akkaraman sheep.

This study reports an anatomical study of the vascular supply in 20 Akkaraman sheep cerebelli from adult subjects of both sexes. The origin and branching pattern of the cerebellar artery vascularising the cerebellar nuclei were studied by gross dissection and vascular injection. Then dissection was performed and vessels nourishing the cerebellar nuclei were documented. Four bilaterally symmetrical cerebellar nuclei were determined as nucleus lateralis cerebelli, nucleus interpositus lateralis cerebelli, and nucleus interpositus medialis cerebelli and nucleus fastigii from lateral to medial side. It has been previously confirmed that vascularisation of the cerebellar nuclei is carried out by intermediary branches of the rostral cerebellar artery and the caudal cerebellar artery. However, this study has confirmed that the caudal cerebellar artery has no contribution in the vascularisation of the cerebellar nuclei.

Animals↗
PubMed2004

[Hepatitis B and D virus infection within Amerindians ethnic groups in the Brazilian Amazon: epidemiological aspects].

Several studies describe very high prevalence rates of infection and disease of hepatitis B and D within Native American population. This is a review of what has been described among Amerindians of Brazilian Amazon. Some groups show low prevalence rates of HBsAg, whereas, others of the same region reveal high endemic pattern, even among individuals less then 10 years of age. HDV is only found in groups of Amazonas province. Transmission may occur by interfamilial dissemination or sexual contact among young adults. Socio-cultural, genetic, and ecological factors are described as determinants of this unique pattern. Nevertheless, the origin of these two viruses is yet to be disclosed. Amerindians population and their genetic memory are a live experiment, which demands a broad investigation, weighting with modern tools, as molecular biology, the influence of historical, genetic, medical and anthropological factors.

Adolescent↗
PubMed2003

Prehistoric tuberculosis in america: adding comments to a literature review.

Tuberculosis is a prehistoric American human disease. This paper reviews the literature and discusses hypotheses for origins and epidemiological patterns of prehistoric tuberculosis. From the last decades, 24 papers about prehistoric tuberculosis were published and 133 cases were reviewed. In South America most are isolated case studies, contrary to North America where more skeletal series were analyzed. Disease was usually located at the deserts of Chile and Peru, Central Plains in USA, and Lake Ontario in Canada. Skeletal remains represent most of the cases, but 16 mummies have also been described. Thirty individuals had lung disease, 19 of them diagnosed by the ribs. More then 100 individuals had osseous tuberculosis and 26 also had it in other organs. As today, transmission of the infection and establishment of the disease were favored by cultural and life-style changes such as sedentarization, crowding, undernutrition, use of dark and insulated houses, and by the frequency of interpersonal contacts. The papers confirm that despite previous perceptions, tuberculosis seems to have occurred in America for millennia. It only had epidemiological expression when special conditions favored its expansion. Occurring as epidemic bursts or low endemic disease, it had differential impact on groups or social segments in America for at least two millennia.

Americas↗
PubMed1997

HIV risk perception, risk behavior, and seroprevalence among female commercial sex workers in Georgetown, Guyana.

A study of 108 female sex workers engaged in prostitution in Georgetown, Guyana, was made in April 1993. Based on interviews and procurement of blood samples, the study investigated relationships between HIV seroprevalences and AIDS knowledge, risk behaviors, client characteristics, and condom use. Street-walkers-as distinct from sex workers in bars, hotels, and Port Georgetown-tended to charge less, be worse off socioeconomically, and have clients who were similarly disadvantaged; they were therefore classified as belonging to a "lower" socio-economic stratum, while the other workers were classified as belonging to a "higher" stratum. The overall HIV seroprevalence found among the sex workers was 25% (95% CI: 17%-33%). But the 50 subjects in the lower stratum had a relatively high seroprevalence (42%, as compared to 10% among those in the higher stratum), accounting for 21 of the 27 HIV-seropositive subjects. Reported patterns of client origins (Guyanese or foreign), worker willingness to have sex without a condom, and condom use by clients differed by stratum. Participants in the higher stratum were more disposed to having sex without a condom. The workers' knowledge of what causes AIDS and how HIV is transmitted was low in both strata; substantial numbers of workers said they had contracted a sexually transmitted disease within the past two years or were users of illicit drugs. Condom use is reportedly less common among Guyanese than foreign clients, suggesting a greater risk of contracting HIV from Guyanese clients or infecting Guyanese clients with it. The HIV seroprevalence among workers who said they had only Guyanese clients was statistically greater than the rate among those who said they had only foreign clients. The HIV seroprevalence among those reporting more than five clients per week was statistically greater than among those reporting fewer. HIV seropositivity was relatively high among the 12 workers who said they used cocaine. Overall, the findings supported the view that interventions targeted at female sex workers and their clients should be strengthened-more specifically, that concerted efforts should be made to intensity condom promotion, distribution, and social marketing; to improve STD services that provide treatment and counseling for female sex workers; and to increase educational activities among the workers' Guyanese clients.

Adolescent↗