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PubMed2005

Unusually high frequency MHC class I alleles in Mauritian origin cynomolgus macaques.

Acute shortages of Indian origin Rhesus macaques significantly hinder HIV/AIDS research. Cellular immune responses are particularly difficult to study because only a subset of animals possess MHC class I (MHC I) alleles with defined peptide-binding specificities. To expand the pool of nonhuman primates suitable for studies of cellular immunity, we defined 66 MHC I alleles in Cynomolgus macaques (Macaca fascicularis) of Chinese, Vietnamese, and Mauritian origin. Most MHC I alleles were found only in animals from a single geographic origin, suggesting that Cynomolgus macaques from different origins are not interchangeable in studies of cellular immunity. Animals from Mauritius may be particularly valuable because >50% of these Cynomolgus macaques share the MHC class I allele combination Mafa-B*430101, Mafa-B*440101, and Mafa-B*460101. The increased MHC I allele sharing of Mauritian origin Cynomolgus macaques may dramatically reduce the overall number of animals needed to study cellular immune responses in nonhuman primates while simultaneously reducing the confounding effects of genetic heterogeneity in HIV/AIDS research.

Alleles↗

PubMed1986

Detection of antibodies to Plasmodium vivax by indirect immunofluorescence: influence of the geographic origin of antigens and serum samples.

The results of a double-blind serological study of 15 sera sampled in a residual focus of vivax malaria transmission in Algeria, and of 7 sera from patients with slide-proven P. vivax infections acquired in India, are analyzed. The reactivity of each of these serum samples was tested by indirect immunofluorescence using 6 different batches of antigen, including 3 batches of P. vivax antigen prepared with isolates from Zaire (Africa), India and the Solomon Islands, respectively. The geometric mean of reciprocal titers (GMRT) calculated on the 7 sera from proven vivax infections fell from 289.8 using the homologous antigen from the same geographic origin (India) to 48.7 using a homologous (vivax) antigen originating from a different continent (Africa). Among the 15 samples from Algeria, the percentage of seropositives decreased from 100% using the homologous P. vivax antigen originating from the same continent (Africa) to 53.3% using a homologous antigen from India. Two aspects are included in the discussion: in seroepidemiological studies, sensitivity could be improved by the use of a homologous antigen from the same geographic origin; in detection of clinical cases of malaria and species identification based on serology, our results stress the need for caution in interpreting serological titers and for taking into account the geographic origin of the isolates used as antigen.

Antigens, Protozoan↗

PubMed1998

Inorganic indicators of the origin of edible salts marketed in Spain from a chemometric approach.

Twenty edible salts marketed in Spain were studied for content of inorganic constituents in order to identify one or more indicators of the origins of salts. In Spain the principal source of salt is seawater, either from the Mediterranean coast or from the Atlantic coast. In addition, some manufactured salts in the dietary category were also considered. Five "Atlantic," 12 "Mediterranean," and 3 dietary salts were analyzed for potassium, magnesium, calcium, strontium, manganese, zinc, and sulfate contents and for alkalinity. Salt samples were first dried for moisture determination. Metals were determined by inductively coupled plasma atomic emission spectrometry, sulfate was determined by turbidimetry, and alkalinity was determined by titration with hydrochloric acid. All the results were expressed as the means for triplicate experiments, as mg of analyte per kg of salt on a dry basis. From these results and by application of chemometric strategies (principal component analysis, variable-variable plots, and cluster analysis) it was found that the potassium content distinguishes sea salts from dietary salts very well, and the contents of strontium and manganese discriminate salts of Atlantic origin versus salts of Mediterranean origin. Dietary salts showed levels of potassium higher than the sea salts, and salts of Atlantic origin had greater strontium and manganese content values than salts of Mediterranean origin.

Potassium↗

PubMed2005

Comparison of pyogenic liver abscesses of biliary and cryptogenic origin. An eight-year analysis in a University Hospital.

OBJECTIVES: The aim of this study is to delineate the clinical features of pyogenic liver abscesses of biliary and cryptogenic origin, and to compare the differences in outcome of patients between the two groups. METHODS: We studied 86 patients, aged 19 years or older, with pyogenic liver abscess admitted to Chung Shan Medical University Hospital, Taichung, Taiwan, between January 1996 and December 2003. The demographic data and medical information of the patients were reviewed and recorded. Of the 86 patients, 34 were classified into the biliary group and 52 were classified into the cryptogenic group. RESULTS: Patients with pyogenic liver abscesses of biliary origin had a higher frequency of underlying malignancy and Murphy's sign compared to those with pyogenic liver abscesses of cryptogenic origin. With respect to specific pathogens, Escherichia coli were more prevalent in the biliary group while Klebsiella pneumoniae were more prevalent in the cryptogenic group. Anaerobic isolates were less frequently cultured in the cryptogenic group than in the biliary group. After adjustment for age, sex, and the duration of symptoms before admission, there was no difference in mortality between both groups (biliary vs cryptogenic: 15% vs 8%; adjusted OR, 1.43; 95% CI, 0.24-8.25; p = 0.899). After adjustment for confounders, patients in the biliary group had higher frequencies of time to defervesce >1 week after admission (68% vs 40%; adjusted OR, 3.05; 95% CI, 1.09-9.04, p = 0.030) and hospital stay >3 weeks (47% vs 15%; adjusted OR, 4.34; 95% CI, 1.45-13.91; p = 0.007) than those in the cryptogenic group. CONCLUSIONS: This report highlights that pyogenic liver abscesses of cryptogenic origin had a benign clinical response, which was associated with shorter duration of hospitalisation and time to defervesce after admission, compared to those of biliary origin.

Adult↗

PubMed1993

Origin of subcortical somatosensory evoked potentials in response to posterior tibial nerve stimulation in humans.

To identify the origin of short latency somatosensory evoked potentials (SSEPs) to posterior tibial nerve stimulation, direct recordings were made from the cervical cord, the ventricular system and the frontal subcortex during 8 neurosurgical operations. The origin of each component of SSEPs was also studied in 7 selected patients with various lesions in the central nervous system. In addition, SSEPs to median nerve stimulation were investigated in 4 of 8 surgical cases and all 7 cases of the lesion study group. Bilateral posterior tibial nerve stimulation in 10 normal subjects showed spinal N28 on the skin of the posterior neck and far-field P30 and N33 components followed by a cortical P38 component at the scalp. Direct recordings made to the mid-brain through the medulla oblongata showed a negative potential with gradually increasing latency. The peak of the negativity in the vicinity of the dorsal column nucleus showed almost the same latency as that of the scalp far-field P30, and positivity with a stationary peak was found above the dorsal column nucleus. Above the mid-pons, there was a stationary negativity with no latency shift, showing the same peak latency as that of scalp N33. The spatiotemporal distributions of P30 and N33 to posterior tibial nerve stimulation were analogous to those of P14 and N18 by median nerve stimulation. Transesophageal and direct cervical cord recordings showed that the spinal N13 phase to median nerve stimulation was reversed between the dorsal and ventral sides of the cervical cord. No such reversal occurred for the spinal N28 potential. Clinical lesion studies showed that changes in P30 and P14, and in N33 and N18 correlated with one another: that is, 1) prolongation of latency of N33 was also observed for N18; 2) absence of P30 was paralleled by the absence of P14. These data suggest that spinal N28 originates from ascending activity such as a dorsal column volley, and scalp P30 comes from activity near the dorsal column nucleus, which is similar to the P14 component of median nerve stimulation. The origin of N33 is thought to be similar to N18 from median nerve stimulation, which originates from brainstem activity below the thalamus.

Adolescent↗

PubMed1997

Self-rating Barthel index compatible with the original Barthel index and the Functional Independence Measure motor score.

To confirm concurrent validity of the final revision of the self-rating Barthel index (SB) and its test-retest reliability, we investigated 171 stroke outpatients without severe aphasia or dementia who were seen by a doctor on predetermined days at eight different hospitals. For 41 patients, the differences in scores among the original Barthel index (BI) and Granger's BI and SB were examined by the Friedman two-way analysis of variance and Wilcoxon matched-pairs signed-ranks test, and the difference in scores between Functional Independence Measure motor score (FIM-MS) and three-level scale FIM-MS was determined by the Wilcoxon's matched-pairs signed-ranks test. Concurrent validity of the SB was confirmed by Spearman's correlation coefficients with the original BI and FIM-MS, and internal consistency of the five measuring instruments was examined. For all 171 patients test-retest reliability of the SB was examined with the Spearman's correlation coefficient for total scores and kappa coefficients for each ADL item. Regression analysis was performed to determine what factors were related with test-retest reliability. Total scores of the SB and Granger's BI and the three-level scale FIM-MS were significantly higher than those of the original BI and FIM-MS, respectively. Correlation coefficients of the SB with the original BI and FIM-MS were 0.994 and 0.904, respectively, and its alpha-coefficient was 0.842. Test-retest reliability of the total score was 0.835 by the correlation coefficient, and kappa coefficients of 1 and 12 ADL items were fair and good, respectively. Regression analysis revealed that self-rating by a patient with a high SB total score is more accurate. Therefore, the SB has good concurrent validity and is well-related with the original BI and FIM, and its test-retest reliability is sufficiently high for practical use.

Activities of Daily Living↗

PubMed1998

Projecting immigrant earnings: the significance of country of origin.

This article asks whether information about immigrants beyond their age, education, and years since migration can be productively used to project their earnings. Although many factors could affect immigrant earnings, what is most useful for Social Security modelling purposes is relevant information that is readily available on a continuous basis. Country of origin is a good candidate, as it is regularly and readily available from several administrative and survey data sources. In this article, microdata samples from the 1960-90 censuses are used to examine the relationship between country of origin and the earnings of immigrants. By following cohorts of immigrants over 10-year intervals, we learn how country of origin affects the initial earnings of immigrants and how the relationship between country of origin and immigrant earnings changes as immigrants continue to live in the United States. The article also presents theoretical insights and empirical evidence about the underlying causes of the link between country of origin and immigrant earnings.

Adult↗

PubMed1999

The origin of ethics and social order in a society without state power.

How ethics and social order in a society without state power had originated and developed is one of enigmas which human beings have tried to solve for a long time. Several theories on the origin of social order have been proposed since the "Social Contract" theory of Thomas Hobbes. According to Hobbes, as a society without state power is in a condition called war, a social contract among men is the origin of social order in a society where every man is against every man. Rousseau says that when human beings reach the stage in which they live in a permanent neighborhood, a property system is introduced. Then, too much ambition and avarice of man who has possessions compel him to propose the formation of a political institution, providing social order which enables him to keep his possessions. According to Nietzsche, the principle of equilibrium, that is, an eye for an eye, a tooth for a tooth is an important concept for the oldest theory of low and morality as well as the basis of justice. The sense of superiority and nobility which a strong man brave enough to take revenge feels is the origin of the antithesis "good" and "bad". Girard says that the sacred violence wielded by the community to sacrifice a surrogate victim brings about social order in a society without state power. All the aforementioned theories seem to have failed to find out that a society without state power has its own ethics that had spontaneously developed on the pagan culture. Previously, I indicated that a society without state power or a society where state power cannot function well, such as the tribal society in northern Albania, has ethics which is based on the ancient concepts of "Guest-god", "food (commensality)" and "blood". In the present paper, I propose a new theory on the origin of ethics and social order, using the model of ethics of the Kanun.

Anomie↗

PubMed1999

Formation of supernumerary euchromatic short arm isochromosomes: parent and cell stage of origin in new cases and review of the literature.

In order to get insight in the formation of isochromosomes we analysed different supernumerary euchromatic short arm isochromosomes for the parent and cell stage of origin. After cytogenetic detection and confirmation by fluorescence-in-situ hybridization we performed short tandem repeat typing in a child with i(9p), three with i(12p) and three with i(18p). The extra chromosomes were monocentric in each case, the i(9p) and i(12p) constitutions were found in mosaic with normal cell lines. Our results and those of other groups indicate a strong role of maternal meiosis in isochromosome formation: in one i(8p), 4 out of 5 i(9p), 7 out of 12 i(12p) and 18 out of 23 i(18p) families a maternal meiotic nondisjunction had occurred prior to the centromere misdivision. For chromosome 18, the majority of isochromosomes originated from a maternal meiosis II error (16/18). For the other tetrasomic constitutions the isochromosomes could be delineated from paternal as well as from maternal origin, the short tandem repeat typing patterns being consistent with meiotic or mitotic cell stages of formation. Thus, independently of the chromosomal origin, in the majority of cases with additional euchromatic isochromosomes maternal meiosis nondisjunction is the initial step followed by centromeric misdivision. Postzygotic nondisjunction as suggested previously due to mosaics observed in tetrasomies 9p and 12p seems to be of minor importance. The observed origin of isochromosomes 18 corresponds to that of trisomy 18, where the majority of cases can be delineated from maternal meiosis II errors.

Child↗

PubMed1999

Development and evolutionary origin of feathers.

Avian feathers are a complex evolutionary novelty characterized by structural diversity and hierarchical development. Here, I propose a functionally neutral model of the origin and evolutionary diversification of bird feathers based on the hierarchical details of feather development. I propose that feathers originated with the evolution of the first feather follicle-a cylindrical epidermal invagination around the base of a dermal papilla. A transition series of follicle and feather morphologies is hypothesized to have evolved through a series of stages of increasing complexity in follicle structure and follicular developmental mechanisms. Follicular evolution proceeded with the origin of the undifferentiated collar (stage I), barb ridges (stage II), helical displacement of barb ridges, barbule plates, and the new barb locus (stage III), differentiation of pennulae of distal and proximal barbules (stage IV), and diversification of barbule structure and the new barb locus position (stage V). The model predicts that the first feather was an undifferentiated cylinder (stage I), which was followed by a tuft of unbranched barbs (stage II). Subsequently, with the origin of the rachis and barbules, the bipinnate feather evolved (stage III), followed then by the pennaceous feather with a closed vane (stage IV) and other structural diversity (stages Va-f). The model is used to evaluate the developmental plausibility of proposed functional theories of the origin of feathers. Early feathers (stages I, II) could have functioned in communication, defense, thermal insulation, or water repellency. Feathers could not have had an aerodynamic function until after bipinnate, closed pennaceous feathers (stage IV) had evolved. The morphology of the integumental structures of the coelurisaurian theropod dinosaurs Sinosauropteryx and Beipiaosaurus are congruent with the model's predictions of the form of early feathers (stage I or II). Additional research is required to examine whether these fossil integumental structures developed from follicles and are homologous with avian feathers. J. Exp. Zool. (Mol. Dev. Evol.) 285:291-306, 1999.

Animals↗

PubMedDate not supplied

[Descriptive study of statistical methods in the original article published on the cigarette smoking habit in four Spanish medical journals (1985-1996)].

BACKGROUND: Being the tobacco use a high-priority subject of investigation and having itself increased the utilization of statistical techniques in biomedical publication the used statistical techniques are described and the statistical accessibility is quantified in the original articles on tobacco use published in four Spanish medical journals. METHODS: Retrospective descriptive study of 154 original articles on the cigarette smoking habit published in 1985-1996 in the journals Atención Primaria, Medicina Clínica (Barcelona), Revista Española de Salud Pública and Revista Clínica Española. An only observer codified the statistic techniques in 14 categories in agreement with the classification processed by Carré et al (1995) from the classification settled down by Emerson and Colditz (1983). The knowledge of bivariable techniques, to simple lineal regression, was stablished as the reference for the study of statistical accessibility. RESULTS: 81.8% original articles used inferential statistics. The most frequently used categories were "Contingency tables" (37.0%), "Descriptive statistics" (18.2%) and "Life tables and analysis of survival" (9.7%). A reader familiarized with bivariable techniques has statistical access to 96.0% for the originals of Revista Española de Salud Pública, 86.2% of Atención Primaria, 66.7% of Medicina Clínia (Barcelona) and 33.3% of Revista Clínica Española. The same reader had statistical access to 100% for the originals published from 1985 to 1987 and 68.1% from 1994 to 1996. CONCLUSIONS: The use of statistical methods depends on the investigation subject and design, the journal and the year of the publication. The decrease of the statistical accessibility recommends to identify the profile of the standard reader in Spain, to adjust his knowledge to the current biomedical literature demand.

Habits↗

PubMed2000

Different patterns of allelic loss (loss of heterozygosity) in recurrent human pituitary tumors provide evidence for multiclonal origins.

Sporadic human pituitary tumors are benign adenomas of monoclonal origin. This implies that they arise from de novo somatic mutation(s) within a single pituitary cell. The availability of original and recurrent/regrown tumors from the same patient allowed testing of the prediction that recurrent/regrown tumors have identical genetic abnormalities as the original tumor sample. We used PCR amplification, from archival slide-extracted DNA, to allelotype microsatellite polymorphisms as an indication of clonality and confirmed this by X chromosome inactivation analysis in samples from women. Tumors from 33 of 49 (67%) patients with two or more specimens showed loss of heterozygosity (LOH) of at least one marker in at least one of their samples. Two patterns of LOH were observed. In pattern A in 14 of 33 (42%) of patients, the LOH pattern of the first tumor was preserved in the second recurrent sample, with some recurrent tumors also showing additional LOH. In these patients, the original and second tumors are presumed to arise from the same original clone with or without progressive accumulation of LOH. In pattern B [19 of 33 (58%) patients], LOH seen in the first tumor was not preserved in the second or subsequent tumors, as evidenced by retention of heterozygosity compared with the first tumor. The simplest explanation is that the second tumor, although still monoclonal, arises from another independently abnormal clone. This was confirmed by X chromosome inactivation analysis in all 11 women where this was informative. These results show that initial and recurrent tumors, of a benign tumor type, are frequently derived from separate independent clones. This suggests that either: (a) more than one abnormal clone is present from the outset though only one dominates; or (b) several clones arise independently at different times. In both scenarios, the initiating event(s) that predisposes to transformation might result in multiclonal hyperplasia, possibly as a consequence of exogenous stimulation.

Adolescent↗

PubMed1975

Origin of leukemic cells in mouse leukemia induced by N-butylnitrosourea.

Administration of N-butylnitrosourea (BNU) induces leukemia in thymectomized C57BL/6J and C3Hf/Bi mice with almost the same high frequency as in non-thymectomized mice. Thymectomized and BNU-treated (C3Hf/Bi times CBA/H-T6T6)F1 mice receiving neonatal thymus tissues from C3Hf donors developed leukemias with or without marked enlargement of the grafts. The origin of leukemic cells was analysed by T6 marker chromosome and thymus allo-antigen theta in this hybrid system. Cells from leukemia with enlarged thymus grafts possessed the sigma-antigen detected by cytotoxicity tests. Cells from leukemia without thymus involvement had no sigma antigen. The leukemic cells arising at the site of thymus grafts were derived from the graft itself (C3Hf) or from the host (C3Hf times CBA/H-T6T6)F1 cells, most probably bone marrow cells which are repopulating into the graft. When the mice were treated with BNU after the lymphoid elements in the grafted thymus had been replaced by host cells, leukemia mainly composed of host-origin cells developed. Leukemia in which neoplastic cells in the thymus grafts were of donor origin and those in other hematopoietic tissues were of host origin was found not infrequently. The present results mean that the target cells in BNU leukemogenesis are distributed within and outside the thymus and that some leukemias are of multifocal tissue origin.

Animals↗

PubMed2001

[Penetrating intraocular injuries caused by foreign bodies of organic origin] ].

OBJECTIVE: To demonstrate two eyes of two patients with a penetrating injury by an organic intraocular foreign body (CNT), to outline the course of treatment and to evaluate anatomical and functional results. MATERIAL AND METHODS: During the period between May and July 1999 the authors treated at their department an 11-year-old girl and a 17-year old boy with a penetrating CNT injury of organic origin. In the girl they extracted a CNT which pierced the sclera and protruded into the vitreous body. The foreign body was extracted by means of a forceps, the site of perforation was treated by a cryosurgical procedure with a radial Silastic filling. The man was shot into the OL by a grain of pepper from an air-gun. The organic body in the vitreous body caused a violent inflammatory reaction in the vitreous body and retina. Early extraction of the CNT could not be made because of an adverse corneal finding which made surgery impossible. The progressing proliferative vitreoretinopathy (PVR) led to repeated formation of epiretinal, subretinal and cyclitic membranes which caused relapsing detachment of the retina (OS). The foreign body was extracted during pars plana vitrectomy (PPV) by the transvitreal route using a forceps. Definite adherence of the retina was achieved during the third PPV, membranectomy and implantation of silicone oil (SO). Final functional success was achieved by eliminating SO and by partial perforating keratoplasty. RESULTS: The CNT in the girl was histologically and parasitologically identified as a fibre of animal origin (animal hair or human eyelash). The follow up period is six months, VOP-5/5 nat., NOT 17 torr, bulbus undisturbed. In the second patient the cultivation finding from the vitreous body was negative. Extensive PVR developed as a result of breakdown products of the organic CNT and led to relapsing OS. Three months after the last operation the bulbus is at rest, the corneal disc clear, the retina attached, VOL-3/60 s + 8.0 D steop., NOT 12 torr. CONCLUSIONS: The final results of treatment of severe devastating penetrating injuries by a CNT is determined by the preoperative condition of the ocular tissues. CNT of organic origin damage intraocular tissues by their breakdown products as well as by more frequent contamination with pathological microorganisms. Our experience provided evidence that penetrating injuries by non-infected CNT of organic origin have a favourable prognosis. But even relapsing and prolonged OS after extraction of the CNT of organic origin and endophthalmitis need not lead to loss of the eye or its function.

Adolescent↗

PubMedDate not supplied

Congenital coronary anomalies of origin and distribution in adults: a coronary arteriographic study.

BACKGROUND: Coronary anomalies should be recognized to avoid problems during coronary intervention and cardiac surgery. METHODS AND RESULTS: We retrospectively reviewed 7400 coronary angiograms to find out the pattern and incidence of coronary anomalies of origin and distribution. We excluded patients with congenital heart diseases, coronary artery fistulae and patients with separate origin of the conus artery. and found 34 cases (0.46%) (22 males), mean age 50.7 +/- 12 years with coronary anomalies. Six cases underwent angiography prior to valve replacement and the rest were part of the evaluation for atherosclerotic coronary artery disease. The most common anomaly was separate origins of the left anterior descending coronary artery and left circumflex coronary artery [n=12 (35.3%)]. The next most common anomalies were origins of the right coronary artery from the left coronary sinus [n=7 (20.6%)] and left circumflex artery from the right sinus [n=6 (20%)]. A single coronary artery was seen in 3 cases (8.8%) which included one case of postmyocardial infarction ventricular septal rupture with triple-vessel disease, and another with two small coronary fistulae. One case each of the following coronary anomalies was found: (i) double right coronary artery, (ii) left anterior descending coronary artery from the right coronary sinus, (iii) all three coronary arteries originating separately from the right sinus, and (iv) left main coronary artery from the right sinus. Of these 34 patients, 11 (32.4%) had significant atherosclerotic disease in the anomalous vessel. CONCLUSIONS: The incidence of primary coronary anomaly seems to be less than that in earlier reports, but the pattern of anomalies appears to be similar.

Adult↗

PubMed2003

Aneurysms at a temporopolar artery origin from the internal carotid artery: report of two cases.

OBJECTIVE AND IMPORTANCE: Origination of the temporopolar artery (TPA) from the supraclinoid internal carotid artery (ICA) represents a rare anatomic variation, and the presence of aneurysms at this uncommon site has never before been reported. CLINICAL PRESENTATION: Two patients presented with a sudden onset of headaches and meningism. Computed tomography demonstrated diffuse subarachnoid hemorrhage in both cases. Cerebral angiography revealed ruptured aneurysms originating at a TPA origin from the ICA. INTERVENTION: The patients were surgically treated, and the aneurysms were successfully clipped. For technical reasons, the TPA was sacrificed in both cases. CONCLUSION: These are the first reported cases of aneurysms originating at the TPA origin from the ICA. Awareness of the existence of this variation is necessary, particularly for the management of superior wall aneurysms of the ICA.

Adult↗

PubMed1976

Comparative morphological remarks on the origin of the posterior femoral cutaneous nerve.

The origin and course of the posterior femoral cutaneous nerve were observed macroscopically in 38 Japanese adult cadavers which were dissected in the University of Hokkaido, Faculty of Medicine during the years 1971/72 and the results obtained were compared with those from some other mammals (rat, rabbit, dog and cat) and a number of bibliographical findings on the other animals. On the basis of the archetype of the pudendal plexus, the site of origin of the posterior femoral cutaneous nerve was divided into seven portions as follows: the sciatic nerve or inferior gluteal nerve (I) and its originating roots (RI), the bigeminal nerve (B) and its originating roots (RB), the part of junction of I and B (CIB), the pudendal nerve (P) and its originating roots (RP). According to the arising mode, the posterior femoral cutaneous nerve was calssified into seven types: Type A (the sciatic nerve type); the nerve arises from I and RI (horse, rat, bird, frog and salamander). Type B (the sciatic transitional type); the nerve arises from I, RI, CIB, RB and B (MAN AND MONKEY). Type C (the bigeminal nerve type); the nerve arises from CIB, RB and B (gorilla, chimpanzee, orangutan, cat and sphenodon). Type D (the pudendal transitional type); the nerve arises from CIB, RB, B, RP and P (dog). Type E (the pudendal nerve type); the nerve arises from RP and P (pig, cattle and rabbit). Type F (the mixed type); a mixture of A to E types. These various patterns in the posterior femoral cutaneous nerve may be explained by the comparative anatomical explanation on the limb medial rotation given in Braus' text-book of Anatomy (Bd. I, S. 273). From these descriptions it is reasonable to presume that the main trunk of the posterior femoral cutaneous nerve of the tetrapod below the Aves arises from the sciatic nerve and is analogous to the gluteal branches of mammals, with its main stem still retained in the pudendal nerve. If the cutaneous area supplied by the posterior femoral cutaneous nerve expands to the lateral border of the buttock in company with the lower limb medial rotation, the part between this area and that supplied by the pudendal nerve is enlarged. At first, these expanded areas are probably supplied by the branches of the pudendal nerve, which gradually become independent to become the main stem of the posterior femoral cutaneous nerve in mammals. This nerve seems, therefore, to be primarily a division of the pedendal nerve, and so in man has various types of arising patterns, A to E, in accordance with the scheme in the phylogeny. Those hypothetical changes are observed in the human sacral plexus, from which the cutaneous nerve arises with a fan-shaped overlapping.

Animals↗

PubMed1992

The simian virus 40 T antigen double hexamer assembles around the DNA at the replication origin.

An initial step in the replication of simian virus (SV40) DNA is the ATP-dependent formation of a double hexamer of the SV40 large tumor (T) antigen at the SV40 DNA replication origin. In the absence of DNA, T antigen assembled into hexamers in the presence of magnesium and ATP. Hexameric T antigen was stable and could be isolated by glycerol gradient centrifugation. The ATPase activities of hexameric and monomeric T antigen isolated from parallel glycerol gradients were identical. However, while monomeric T antigen was active in the ATP-dependent binding, untwisting, unwinding, and replication of SV40 origin-containing DNA, hexameric T antigen was inactive in these reactions. Isolated hexamers incubated at 37 degrees C in the presence of ATP remained intact, but dissociated into monomers when incubated at 37 degrees C in the absence of ATP. This dissociation restored the activity of these preparations in the DNA replication reaction, indicating that hexameric T antigen is not permanently inactivated but merely assembled into a nonproductive structure. We propose that the two hexamers of T antigen at the SV40 origin assemble around the DNA from monomer T antigen in solution. This complex untwists the DNA at the origin, melting specific DNA sequences. The resulting single-stranded regions may be utilized by the T antigen helicase activity to initiate DNA unwinding bidirectionally from the origin.

Adenosine Triphosphate↗